According to a study of the European Commission, approximately one million hips are replaced by prostheses worldwide every year. The interaction of the human body with foreign materials that are subjected to alternating mechanical load in a highly corrosive environment still provides challenges. The main factors affecting prosthesis failure are stress shielding effect and poor osseointegration. In this thesis the problem of prosthesis failure has been approached from the material and from the osseointegration point of view trying to give a global solution to the problem. Niobium and hafnium, which are demonstrated to be totally biocompatible, were used to design a Ti-based alloy. The effect of the alloying elements regarding microstructure and elastic modulus was studied and the best composition was deeply characterized in terms of microstructure, elastic modulus, corrosion resistance and superficial energy. Recombinant fragments of fibronectin were synthesised spanning the cell attachment site and the heparin binding domain which are important for cell viability. These motifs were used to functionalise the surface of the TiNbHf alloy. Two tethering methods were studied: physisorption and silanisation. Silanisation was not used before to immobilise fibronectin recombinant fragments onto metallic substrates and in this thesis, its good performance was demonstrated. In vitro studies were made with each fragment and with different combinations of the fragments, which showed the importance of the heparin binding domain to obtain a cell response equivalent to that of fibronectin in terms of cell adhesion, proliferation and differentiation. / De acuerdo con un estudio de la Comisión Europea, aproximadamente un millón de caderas son remplazadas por prótesis en el mundo anualmente. La interacción del cuerpo humano con materiales externos sujetos a una carga mecánica alternante en un medio altamente corrosivo todavía presenta ciertos desafíos. Los factores que contribuyen principalmente al fallo de una prótesis son el apantallamiento de cargas y la pobre osteointegracion. En la presente tesis el problema de la fallida de prótesis ha sido abordado desde el punto de vista del material y de la osteointegracion en un intento de dar una solución global al problema. El niobio y el hafnio, cuya total biocompatibilidad ha sido demostrada, se han utilizado para diseñar una aleación de titanio. El efecto de dichos aleantes respecto a la microestructura y el módulo elástico ha sido estudiado y la mejor composición ha sido profundamente caracterizada en términos de microestructura, módulo elástico, resistencia a la corrosión y energía superficial. Fragmentos recombinados de fibronectina han sido sintetizados abarcando la zona de adhesión celular y la unión de heparina, las cuales son esenciales para la viabilidad celular. Dichos motivos han sido utilizados para funcionalizar la superficie de la aleación TiNbHf. Dos métodos de unión diferentes han sido estudiados: fisisorción y silanización. La silanización es un método que no se ha utilizado hasta el momento para inmovilizar fragmentos de fibronectina sobre superficies metálicas y en la presente tesis su idoneidad ha sido demostrada. Finalmente, estudios celulares in vitro se han llevado a cabo con cada fragmento y con diferentes combinaciones de ambos, lo cual ha mostrado la importancia de la zona de unión de heparina para obtener una respuesta celular equivalente a la obtenida con la molécula de fibronectina en cuanto a adhesión celular, proliferación y diferenciación.

Leather is a natural material that can be used in different environments and often under aggressive environmental conditions that may cause premature ageing. Since upholstery leather is considered a very high-tech product, a long service life is expected by the costumer. According to different studies carried out on historical/ancient leathers by leather conservation centers and museums, leather also is strongly affected by these three main environmental parameters: temperature, relative humidity, and UV radiation. The aim of this work is to study the effect of the environment exposure, to identify the most important variables affecting this weathering process and to check for interactions among the three factors on the degradation and leather ageing on wet-blue and wet-white upholstery leather, applying the leather to natural weathering, tropical environmental exposure and finally a combination of the three critical factors. The tests were carried out on Spanish pickled cattle hides. Two types of tanned leather were tested: on the one hand, chrome tanned leather and on the other hand, wet-white tanned leather using tetrakishydroxymethylphosphonium sulphate (THPS) and silicate-phenolic synthetic and retanned with protein-amide polymer. Both types of leathers were finished using common industrial formulation. Firstly, the work was undertaken to better understand the effect of degradation of chrome tanned leather and wet-white leather and the physical and chemical processes occurring during long-term exposure to outdoor conditions. The samples were tested before and after 20, 40, 80, 120 and 180 days of exposure. Increasing the levels of the three critical weathering variables, the leathers were exposed to tropical environment using a climatic chamber at 70ºC and 95% relative humidity during 7, 14 and 21 days. Additionally half of the leathers were exposed to UV radiation for 4 days. Finally, the leathers were exposed to accelerating ageing test using a multilevel centralized factorial experimental design and an analysis of variance (ANOVA) with 3 variables and 2 levels (23). The evaluation of the leathers was carried out with physical, fastness, chemical and organoleptic properties of the leathers. With the natural weathering studies, wet-white leather and chrome-tanned leather show a different behavior to leather ageing. The loss in properties in chrome-tanned leather increases steadily until 40 days exposure, and after this point the leather stabilizes and no longer degrades. In wet-white leather, however, there is a progressive loss in properties but stabilization does not occur until a period of exposure of 80-120 days. Tropical environmental exposure causes physical and chemical degradation of both types of tanned leather. In chrome-tanned leather, the loss of all properties occurs progressively over time, in wet-white leather it occurs only after 7 days exposure, and is followed by carbonization of the leathers after 14 days exposure. Additionally, when wet-white samples are exposed for long periods at high relative humidity are attacked by fungi. Resistance and dimensional stability of wet-white leather both in accelerated ageing tests and natural weathering exposure is higher than that of chrome-tanned leather. However, these leathers have the disadvantage of not resisting simultaneous exposure to high temperatures and high relative humidity, that's to say, tropical environmental conditions. Results from experimental designs prove again that chrome-tanned leather and wet-white leather have a different ageing behavior. Whereas chrome-tanned leathers are strongly affected by UV radiation, wet-white leathers are strongly affected by relative humidity. Additionally, no correlation has been found between ageing caused by natural weathering and that caused under controlled conditions in the laboratory. / La pell és un material natural que pot ser utilitzat en diferents ambients i molt sovint pot ser sotmès a condicions ambientals agressives provocant el seu envelliment prematur. Segons diferents estudis portats a terme en pells històriques procedents de centres de conservació de la pell i museus, la pell es veu afectada pels tres paràmetres ambientals principals: temperatura, humitat relativa i radiació UV. L’objectiu d’aquest treball és estudiar l’efecte de l’exposició ambiental, identificar les variables més importants que afecten al procés d’envelliment i buscar les interaccions entre els tres factors, en la degradació i envelliment de la pell adobada al crom i pell adobada wet-white per tapisseria, sotmetent la pell a exposició directa a la intempèrie, exposició a ambient tropical artificial i finalment a una combinació dels tres factors crítics. Els assajos es porten a terme amb pell vacuna piquelada, es preparen dos tipus de pell: pell adobada al crom, i pell adobada wer-white utilitzant sulfat de tetrakishidroximetilfosfoni (THPS) i sintètic silicat-fenòlic readobat amb polímer de proteína-amida. Les pells s’acaben utilitzant una formulació industrial estàndard. Inicialment el treball pretén entendre millor l’efecte de la degradació de la pell adobada al crom i pell adobada wet-white, i els processos físics i químics que ocorren durant una exposició prolongada a les condicions ambientals exteriors. Les mostres s’analitzen abans i després de 20, 40, 80, 120 i 180 dies d’exposició. Incrementant els nivells de les tres variables crítiques d’envelliment, les pells s’exposen a un ambient tropical utilitzant una cambra climàtica a 70ºC i 95% d’humitat relativa durant 7, 14 i 21 dies d’exposició. Addicionalment la meitat de les pells s’exposen a radiació UV durant 4 dies. Finalment, les pells s’exposen a un test d’envelliment accelerat utilitzant un disseny experimental factorial centralitzat, com a eina estadística per estimar els efectes dels paràmetres es treballa amb un anàlisis de variància (ANOVA) amb 3 variables i 2 nivells cadascun. L’avaluació de les pell es porta a terme a través de l’anàlisi de propietats físiques, químiques i organolèptiques de les pells. En els estudis d’exposició natural les pells adobades al crom i les pells adobades wet-white mostren un comportament diferent a l’envelliment. Mentre que per la pell adobada al crom la pèrdua de propietats físiques es produeix als 40 dies d’exposició i després d’aquest punt la pell s’estabilitza i no es degrada més, en el cas de la pell adobada wet-white es produeix una pèrdua progressiva de les propietats però l’estabilització no es produeix fins als 80-120 dies. L’exposició a un ambient tropical artificial causa una degradació física i química en els dos tipus de pells. En la pell adobada al crom, la pèrdua de propietats ocorre progressivament en el temps, mentre que en la pell adobada wet-white això només succeeix després de 7 dies d’exposició, seguit d’una carbonització després de 14 dies d’exposició. A més, quan la pell adobada wet-white s’exposa a períodes llargs d’humitat relativa alta és atacada per fongs. La resistència i l’estabilitat dimensional de la pell adobada wet-white, tant en l’assaig d’envelliment accelerat com en l’exposició ambiental natural, és molt superior a la de la pell adobada al crom. Tanmateix, aquesta pell té la desavantatge de no resistir simultàniament l’exposició a elevada temperatura i elevada humitat relativa, condicions de l’ambient tropical. Els resultats dels dissenys experimentals demostren una altra vegada que la pell adobada al crom i la pell adobada wet-white tenen un comportament a l’envelliment molt diferent. Mentre que la pell adobada al crom es veu molt afectada per la radiació UV, la pell adobada wet-white està afecta per la humitat relativa. Addicionalment, no es troba cap correlació entre l’envelliment causat per exposició ambiental natural i el causat sota condicions controlades al laboratori.

Historical decorated glass and glazed ceramics are studied with the object to determine the technology of production and to relate it with the optical properties (colour, shine, opacity). Four different case of study are investigated: production technology and replication of lead antimonate yellow glass from New Kingdom Egypt and the Roman Empire, technology of production of polychrome lustre, analyses of Syrian lustre pottery (12th–14th centuries AD) and study of color and dichroism of silver stained glasses. These different coloured glazes or glasses have in common to be produced by the presence of micro or nanoparticles embedded into the glaze which give their special optical effect. Chemical and microstructural analyses are performed using a selection of complementary Microscopic and Spectroscopic techniques that are the most adequate for the analyses of each decoration. Physical optical properties are also modeled and measured by means of UV-Vis spectroscopy. The composition and structure of the different phases formed during the processing of the decorations in historical times is obtained with the object to learn about their stability and processing conditions and to relate them to their optical properties

Today we are experiencing an "eco friendly boom"; which includes the developing of ecological processes that have a smaller impact in the environment. This is the reason that prompted me to carrying out this thesis; the aim is to use a vegetable extract as a sustainable product for the pre-tanning processes. This study considers the use of the fruit of the Tara tree as a raw material source of tannins with low carbon footprint and proposes alternatives to avoid or reduce the use of commercial vegetable extracts, synthetic products and mineral salts that require non sustainable processes. Various experimental designs have been developed as to obtain new tailored Tara tannins by both chemical and physical modification, in order to obtain a higher percentage of tannins, and therefore improve its tanning capability, also reducing the astringency and improving the penetration of the tannin molecules through the leather structure. In chemical modifications, several aqueous extractions at different temperatures and combined with some chemicals, have been developed and optimized in order to increase the tannin content and reduce the astringency. The degree of hydrolysis has controlled by measuring the Gallic acid content by means of HPLC (High performance liquid Chromatography). In the physical modification part, the Tara has been milled and sieved, at several particle sizes, with the aim of obtaining a smaller molecular size. Both chemical and physical modifications were tested in hides, in a wet-white pre-tanning process, combining them with the fewest possible commercial vegetable extracts and syntans. The formulations have been optimized by experimental design. All the resulting leather products and final baths have been analyzed with physical and chemical tests respectively, to determine if they comply with the parameters established by the IULTCS (International Union of Leather Technologists and Chemists Societies). Finally, a life cycle assessment has been developed, in order to determine the environmental improvement of the new modified product, obtained in this thesis. This thesis is also supported with articles published in magazines specialized in the Leather sector. There are two articles published in the Journal of the American Leather Chemists Association (JALCA), named: *Low carbon products for the design of innovative leather processes. Part I: determination of the optimal chemical modification of tara. . (JALCA, Vol. 108, pag. 386-391, 2013) *Low carbon products for the design of innovative leather processes. Part II: determination of the optimal physical modification of tara. (JALCA, Vol. 109, pag. 25-31, 2014) One article pending to be published in the Journal of AQEIC (Spanish Leather Chemists Association) Application of Sustainable tannins with Low carbon footprint,And presented in the 62nd Congress of AQEIC, Lorca (Murcia), May 10th and 11th, 2013 Presentation: "Aplicación de taninos sostenibles con baja huella de carbono"

Polymers are becoming preferred materials in biomedical applications because of their vast diversity of properties, functionalities and applications. Properties as mechanical strength, stability against degradation, biocompatibility and biodegradability, among others, have been attractive for different medical applications. One of the most interesting applications of these materials is drug delivery systems. Biodegradable polymers and copolymers are the preferred materials for the manufacture of a variety of devices for temporal applications in medicine and pharmacology; these biodegradable polymers can be chemically synthesized or biologically produced. Biotechnological polymers have attracted much attention because two main advantages; first, they are produced from renewable resources; and second, as they are biologically produced they are biocompatible, biodegradable and bioresorbable materials. Thus, modification of biotechnological polymers to obtain specific properties or functionalities is a good strategy for the development of promising biomedical materials. In this Thesis the water soluble biotechnological polymer poly(ß,L-malic acid) (PMLA) was modified to change its hydrophilic character to produce non water-soluble polymers capable of forming particulate systems for drug encapsulation and controlled release. PMLA is a polyester-3 with a pendant carboxylic group; it is biocompatible, biodegradable and bioresorbable. The carboxylic side group can be substituted in order to modify the properties of the polymer. The polymer as polyelectrolyte, is also water-soluble. Different strategies were used for polymer derivatization: direct esterification and amidation through the activation of the carboxylic side groups with carbodiimides; ionic complex formation with a cationic drug (Doxorubicin); and esterification with aliphatic long chains by a two step method employing thiol-ene click reactions. Obtained PMLA derivatives resulted in hydrophobic or amphiphilic polymers, which were appropriated for nanoparticle formation, either by emulsion solvent evaporation or by precipitation dialysis techniques. Derivatives physicochemical characterization was made by 1H and 13C nuclear magnetic resonance (NMR) spectroscopy, gel permeation chromatography (GPC) and differential scanning calorimetry. Hydrolytic degradation was followed by GPC and 1H NMR, while particles were observed by scanning electron microscopy and their size and surface charge characterized by dynamic light scattering and ζ-potential measurement. Assays of drug encapsulation and release were also performed and cytotoxicity tests were done on cancer cell lines. Nanoparticles (100-300 nm aprox.) were obtained from all PMLA derivatives, except for the ionic complex which formed microparticles. Nanoparticles showed potential as drug delivery systems since they were able to encapsulate the anticancer drugs Temozolomide and Doxorubicin, as well as the model drugs Theophylline and Carbamazepine. Drug release was assessed under physiological conditions; the release rate was found to depend on encapsulation method, drug and polymer derivative. Hydrolytic degradation assays showed that free malic acid and the organic compound derived from the reagent used for modification were the last products of aqueous degradation of PMLA derivatives. Cytotoxicity tests demonstrated the low toxicity of the synthesized derivatives. Results generated in this Thesis suggest that the biotechnological polymer PMLA is a material of interest as a platform for the design and development of biodegradable drug delivery systems with potential in the therapy of diseases considered today challenging for pharmacologic treatment.

Section 26 of the Labour Relations Act 95 of 1996 makes provision for the introduction of closed shop agreements at the workplace between majority unions and employers. All employees covered by such agreements are required to be members of such unions or otherwise face the possibility of dismissal. "Conscientious objector" employees are an exception to this rule. The purpose of this submission is to investigate the constitutional validity of s26 in the light of the fundamental right to freedom of association in the Constitution of the Republic of South Africa, 1 996 whilst investigating the position of "conscientious objectors" in certain foreign jurisdictions. / Thesis (LL.M. (Labour Law))--North-West University, Potchefstroom Campus, 2006.

La recerca de nous catalitzadors sòlids bàsics de tipus Brønsted ha estat en el punt de mira de nombrosos estudis recents, degut al seu gran potencial per a dur a terme reaccions de condensació ald-olica. Aquests materials sòlids eviten l'ús industrial de solucions aquoses de tipus KOH i NaOH, reduint significativament els problemes de generació de residus, corrosió o no reutilització dels catalitzadors. En els darrers anys, ha crescut l'interès en l'estudi dels hidròxids dobles laminars (layered double hydroxides, HDL) o compostos de tipus hidrotalcita, com a catalitzadors de nombroses reaccions, o bé, en altres aplicacions.Per tal de generar catalitzadors sòlids bàsics de tipus Brønsted, un HDL de Mg-Al, tractat tèrmicament, pot ser reconstruït degut al seu conegut efecte memòria. La reconstrucció es realitza per contacte del sòlid amb vapor d'aigua (fase gas) o per immersió en aigua liquida (fase liquida), ambdues en atmosfera inert. Un aspecte en discussió es la relació entre el procediment de rehidratació aplicat i l'activitat catalítica dels HDL de Mg-Al reconstruïts. En aquest treball s'han estudiat detingudament els processos de rehidratació en fase gas o en fase liquida. Donat que el procés de rehidratació porta a la formació d'un material de tipus meixnerita, el qual presenta centres bàsics de Brønsted en l'espai interlaminar, es mostra que l'accessibilitat cap a aquests centres bàsics es un factor determinant de l'activitat d'aquests catalitzadors en reaccions de condensació aldòlica. Per altra banda, s'ha estudiat també la sensibilitat dels catalitzadors HDL de Mg-Al reconstruïts en fase gas, a l'addició de promotors alcalins, per tal d'assegurar la seva influencia en l'activitat catalítica.La recerca descrita en aquest treball de tesi s'ha centrat en l'estudi dels procediments d'activació/rehidratació, i en conseqüència, en la morfologia dels catalitzadors de tipus hidrotalcita. Les propietats bàsiques s'han caracteritzat mitjançant diferents tècniques, com la desorció a temperatura programada de diferents molècules sonda, i mitjançant reaccions model del tipus condensació aldòlica entre citral-cetones. Una altra alternativa interessant és l'ús de líquids iònics, amb una amplia aplicació com a solvents, degut a les seves propietats físiques i químiques. L'ús dels líquids iònics amb propietats bàsiques, pot proporcionar catalitzadors eficients en moltes reaccions de condensació aldòlica. En aquest sentit, s'analitzen diferents aspectes com l'ús d'un líquid iònic suportat (l'hidròxid de colina), la seva activitat catalítica en diverses reaccions de condensació aldòlica i la caracterització de les propietats bàsiques. / The research about the use of new solid Brønsted-type basic catalysts has been the focus of many recent studies because of their potential for aldol condensation reactions. Besides, these solid materials avoid the industrially use of KOH and NaOH reducing several problems such as waste production, corrosion and not recovery of the catalysts. In recent years, there has been a growing interest in layered double hydroxides (LDH) or hydrotalcite-like compounds to perform numerous catalytic reactions and other applications. In order to provide solid Brønstedtype basic catalysts, a thermally treated Mg-Al LDH can be reconstructed due to its known memory effect, by rehydration in contact with water vapour or immersed in liquid water under decarbonated atmosphere. The catalytic performance of a reconstructed Mg-Al LDH in relation to the rehydration procedure applied is not well understood. In this work, careful studies of rehydration procedures (gas or liquid phase) over decomposed Mg-Al LDH have been performed. Since the rehydration process leads to a meixnerite-like material, having Brønsted basic sites in the interlayer space, it is shown that accessibility towards these basic sites is a key factor determining the performance of the catalysts in aldol condensation reactions. The sensitivity of gas-phase reconstructed Mg-Al LDH to the addition of alkaline promoters has been also studied to assess their influence on the catalytic performance. The research described in this thesis has focussed on getting more insight in the activation/rehydration procedure and consequently, in the final morphology of hydrotalcite-like compounds. The basic properties have been characterised by several techniques such as temperature programmed des orption of different probe molecules and by illustrative test reactions suchas the liquid-phase aldol condensation between citral-ketones. Another interesting alternative is the use of ionic liquids, which have attracted a large attention as solvents in recent years, due to their physical and chemical properties. Besides, the use of ionic liquids with basic properties could provide efficient catalysts for several condensation reactions. In this area, we also report the use of a supported ionic liquid (choline hydroxide), its catalytic performance in aldol condensation reactions and the characterisation of basic properties.

Metal nanoparticles catalysts considered in this work included systems consistingessentially of a single metal component (Ag) and bimetallic system. Bimetallic systemsof miscible (Au-Cu and Au-Ag) and immiscible components (Ir-Au) have beeninvestigated. The study of these materials with chemical probes including chemisorptionand selected catalytic reaction, in conjunction with physical and chemical methods suchas electron microscopy, X-ray diffraction (XRD), temperature programmed reduction(TPR), UV-vis, photoelectron spectroscopy (XPS) has been performed to contribute theknowledge of their structures. The fact that surface composition can differ substantiallyfrom bulk composition was also studied. High resolution electron microscopy (HRTEM)provided independent evidence of the highly dispersed nature of the metal clusters.Concepts concerning the effect of additives on the structure and physicochemical andcatalytic properties of oxide catalysts in selective oxidation reactions were considered.This work was also carried out in an attempt to study the different oxygen species formedon silver. Of particular interest is to understand the role and nature of the elusivesubsurface O species in the function of silver as an oxidant catalyst. The effect ofadditives on acid-base and redox properties and on their bearing on catalytic performancewas discussed, with particular emphasis on alkaline metal additives such as cesium andsodium. The phenomena occurring in monophasic and supported mixed oxide containingthe additives, including modification of structure, segregation, defect formation and spilloverof the reactants was also described.The nature of the surface of the bimetallic systems was the question of interest. Will theindividual clusters be monometallic or will they contain atoms of both metals andtherefore be bimetallic? It is interesting to consider how the state of dispersion the metalcatalysts affects the relationship between chemisorption capacity or catalytic activity andcatalyst composition. The bimetallic clusters discussed thus far have been combination ofa Group VIII and a Group IB metal. In spite of the great importance in petrochemistry,skeletal hydrocarbon reactions, such as hydrogenolysis of methylcyclopentane, offers aninteresting fingerprint of the dependence of specific rate on catalyst structure. The firstreported case of a reaction with large dependence on catalyst structure was performed forneopentane on platinum. This result led Boudart to classify reactions on metals as: (i)"facile" or "structure-insensitive" reactions, for which the specific rate does not dependupon the size of the metal particle, and (ii) "demanding" or "structure sensitive"reactions, for which the specific rate is highly dependent on the metal dispersion. Therate per surface metal atom is the fundamental interest. Thus, the metal dispersion isextremely important parameter to be determined. An experimental scheme based onselective H2 chemisorption was developed to investigate the surface composition ofbimetallic system. With this capability, the activity of such a catalyst was referred to theamount of metal in the surface rather than to the metal content of the catalyst as a whole.The interaction between catalytically active metal oxide particles and oxide carriersgreatly influences their structure and size. Vanadia catalysts constitute also a relevantexample of the influence of this interaction. Accordingly, it was decided to study theeffect of the support (TiO2 and MCM-41) with the aim of understanding theinterrelations on the catalytic properties of V2O5 as a way to improve its performance forthe selective oxidation of ethanol.Finally, the catalytic role of the different basic sites in hydrotalcite interlayer wasenvisaged through the study of the styrene epoxidation in liquid phase. Hydrotalcite-likecompounds are not only interesting for their industrial applications, but are also beautifulexamples of the scientific preparation of catalysts. All the stages of the preparation of acatalyst based on hydrotalcite-like precursor need precise chemical foundations in orderto avoid inhomogeneties and/or chemical segregations, which would be detrimental tothe properties of the final compounds. Layered double hydroxides (LDHs), also knownas hydrotalcites or anionic clays, are a class of ionic lamellar compounds made ofpositive-charged hydroxide layers with charge balancing anions and water moleculessandwiched between layers. Exfoliated Mg-Al layered double hydroxide in water wasinvestigated in the styrene epoxidation. The change in the basic properties during therehydration process of the calcined samples as well the influence on catalytic activitywas studied. Hydrotalcites are very attractive for this type of oxidation reaction becausetheir ability to give Lewis type acid-base bifunctional catalysts or basic catalysts withBrönsted type sites, proceeding from the mixed oxide and the meixnerite-like structures,respectively. / En este trabajo se han sintetizado y estudiado diferentes catalizadores a base denanopartículas metálicas con diferentes tamaños y morfologías. Se han estudiado tantosistemas monometálicos como bimetálicos con componentes de diferentes miscibilidad (porejemplo sistemas Au-Cu y Au-Ag de total miscibilidad, así como Ir-Au de prácticamentetotal inmiscibilidad) con la finalidad de estudiar el cambio que producen tanto en el tamañocomo en la morfología de las nanopartículas obtenidas.Los nanomateriales obtenidos han sido estudiados mediante el empleo de diferentestécnicas de caracterización como pueden ser, fisisorción, quimisorción microscopiaelectrónica (SEM-TEM), difracción de rayos X (XRD), reducción a temperaturaprogramada (TPR), espectroscopia ultravioleta-visible (UV-vis), espectroscopiafotoelectrónica (XPS), etc., así como mediante diferentes ensayos catalíticos modelo con lafinalidad de correlacionar las propiedades físico-químicas de dichos materiales con losmétodos de síntesis de éstos.Se ha hecho especial énfasis en el estudio de las diferentes especies de oxígeno quepresentan estos nanomateriales en superficie, así como su correlación con la actividadcatalítica que presentan en diferentes reacciones de oxidación selectiva de olefinas. Por otraparte, la modificación de las propiedades ácido-base de dichos materiales y su carácterredox cuando se adiciona metales alcalinos del tipo sodio y cesio, también ha sidoexhaustivamente estudiado.La formación de sistemas bimetálicos y su homogeneidad, así como el efecto de dispersióny el cambio en sus propiedades físico-químicas que hace un metal sobre el otro, ha sidotambién objeto de estudio en este trabajo. Este hecho se ha puesto en evidencia en elestudio de reacciones de hidrogenolisis del metilciclopentano que permite una buenacomprensión de la actividad catalítica, así como de la dependencia de la estructura en laactividad catalítica previamente ya descrita por Boudart.La interacción entre las especies metálicas cataliticamente activas y los soportes empleadostambién pueden ejercer una notable influencia en la estructura y tamaño de la especieactiva, y por consiguiente en el comportamiento catalítico. En este contexto, se hanestudiado la interacción de óxido de vanadio en diferentes soportes como TiO2 y MCM-4,para comprender el comportamiento catalítico del V2O5 en otra reacción test como es la deoxidación selectiva del etanol.Finalmente, el papel del los diferentes sitios básicos de materiales tipo hidrotalcita, elestudio de la exfoliación de dichos materiales y el cambio en sus propiedades básicasdespués de diferentes protocolos de rehidratación han sido estudiados en otra reacción testcomo es la reacción de epoxidación del estireno en fase liquida.

En los últimos años, existe un creciente interés en la sustitución de viejas tecnologías por alternativas catalíticas más limpias para el desarrollo de procesos respetuosos con el medio ambiente para la industria química. De esta manera, es un desafío continuo encontrar nuevos catalizadores básicos capaces de realizar, con alta actividad y selectividad, las reacciones para la síntesis de productos de alto valor añadido tanto químicos como farmacéuticos. La investigación descrita en esta Tesis se ha centrado en el estudio de nuevos protocolos de síntesis para catalizadores básicos. Nuevos materiales con basicidad controlada, tipo hidrotalcita, se han sintetizado a lo largo de esta Tesis. Por otra parte, se ha desarrollado un nuevo protocolo de síntesis para líquidos iónicos alifáticos de cadena corta. Además, se presenta un amplio estudio de las propiedades físico-químicas de los líquidos iónicos sintetizados. Las propiedades básicas de los catalizadores desarrollados se han caracterizado por diversas técnicas y así como mediante el empleo de reacciones modelo. Por consiguiente, el trabajo realizado en esta Tesis permite avanzar en el diseño de nuevos sistemas catalíticos más activos y eficientes para su utilización en procesos de química fina. / In the last years, there is an increasing interest in substituting old technologies by cleaner catalytic alternatives to afford more environmental friendly processes in the chemical industry. In this way, it is a continuous challenge to find new base catalysts able to perform, with high activity and selectivity, reactions for the synthesis of pharmaceutical and fine chemicals.The research described in this thesis has focused on the study of new synthesis protocols for base catalysts. New types of hydrotalcite-like materials with controlled basicity were obtained. Also, a new synthesis protocol for short aliphatic chain ionic liquids and an extensive study of their physico-chemical properties is presented. Their basic properties have been characterized by several techniques and by illustrative test reactions. The work done in this thesis can be regarded as a progress in the design of new catalytic systems, more active and efficient for use in fine chemical processes.

Air pollution is a serious issue that affects human health, the environment and the climate at levels from local to global scales. The main processes that affect air pollution levels are: emissions, chemistry, transport and deposition. Air quality models (AQMs) are mathematical tools that describe relevant physicochemical processes and quantify concentrations of air pollutants. Therefore, AQMs can be used to develop and detail measures taken to reduce air quality problems. Several AQMs are currently used and they have undergone a rapid evolution in recent years. Computer capacity has increased during the last decade enabling us to use higher spatial resolutions and more complex parameterizations schemes that resolve more complex atmospheric processes. Moreover, previous research has shown that the feedbacks between meteorology and chemistry are important in the context of many research applications. Therefore, this increase in computing power allows accurately simulate those feedbacks (online modelling). Online models are becoming more used in the atmospheric community. The NMMB/BSC Chemical Transport Model (NMMB/BSC-CTM) is being developed through an ongoing team effort at the Earth Sciences Department of the Barcelona Supercomputing Center (BSC). The main motivation for this thesis is to contribute in the development of a unified fully coupled chemical weather prediction system able to solve gas-aerosol-meteorology interactions within a wide range of scales on local to global domains that can be used in both operational and research applications. In this sense, the focus in this Ph.D. has been on the development and evaluation of the tropospheric gas-phase chemistry within the online Global / Regional atmospheric model NMMB/BSC-CTM. With the meteorological core NMMB as the starting point, different parameterizations of several atmospheric chemistry processes such as dry deposition, photolysis, wet deposition, gas-phase chemistry, and stratospheric ozone handling have been reviewed, implemented and evaluated during this Ph.D. thesis. A complete spatial, temporal and vertical model evaluation of the relevant chemical species using different observational data has been performed in this Ph.D. thesis. Observational data has included ground-monitoring stations, ozonesondes, satellite data, climatologies and, aircraft campaigns. This is the first time that the gas-phase chemistry of the NMMB/BSC-CTM has been evaluated on a regional and global scales over a full year. Concerning the model evaluation in the regional scale, we had the opportunity to participate in the Air Quality Model Evaluation International Initiative (AQMEII) Phase2 which aims to intercompare online coupled regional-scale models over North America and Europe. In this sense, we were participating in this initiative in the European runs with NMMB/BSC-CTM model. The model evaluations have shown a good agreement with observations. Overall, the model performance corresponds to state-of-the-art regional and global AQMs. / La contaminació de l’aire és un problema greu que afecta la salut humana i el medi ambient, tant a escala local com global. Els principals processos que concerneixen els nivells de contaminació de l’aire són les emissions, la química, el transport i la deposició. Els Models de Qualitat de l’Aire (AQMS) són eines matemàtiques que descriuen aquests processos fisicoquímics i quantifiquen les concentracions de contaminants de l’aire. Per tant, els AQMS es poden utilitzar per desenvolupar i detallar les mesures preses per reduir la mala qualitat de l’aire. Actualment, es fan servir diversos AQMS i aquests darrers anys han evolucionat molt ràpidament. La capacitat de la computació ha augmentat durant l’última dècada, i això ha fet possible una resolució espacial més bona i uns esquemes de parametritzacions més complexos que resolen més processos atmosfèrics. D’una altra banda, la investigació ha demostrat que els feedbacks entre la meteorologia i la química són certament importants en moltes aplicacions de recerca. Per tant, l’augment de la potència de càlcul permet simular acuradament aquests feedbacks (modelizació online). Els models online són cada vegada més utilitzats en la comunitat atmosfèrica. El NMMB/BSC Chemical Transport Model (NMMB/BSC-CTM) es desenvolupa gràcies a un esforç d’equip al Departament de Ciències de la Terra del Barcelona Supercomputing Center (BSC). La principal motivació d’aquesta tesi és contribuir al desenvolupament i a l’avaluació d’un sistema de predicció unificat que sigui capaç de resoldre les interaccions gas-aerosolmeteorologia dins un ampli rang d’escales, des de dominis locals a globals, i que pugui ser utilitzat tant en aplicacions operatives com d’investigació. En aquest sentit, el principal objectiu d’aquesta tesi doctoral és el desenvolupament i l’avaluació de la química troposfèrica en fase gasosa del model online global/regional NMMB/BSC-CTM. Utilitzant el nucli meteorològic NMMB com a punt de partida, diverses parametritzacions de processos químics atmosfèrics com ara la deposició seca, la fotòlisi, la química dels núvol, la química en fase gasosa i l’intercanvi d’ozó entre estratosfera i troposfera han estat revisats, implementats i avaluats durant aquesta tesi doctoral. S’ha dut a terme una avaluació completa a nivell espacial, temporal i vertical de les espècies químiques més rellevants mitjançant diverses observacions a escala global i regional. Aquestes observacions inclouen estacions a nivell de superfície, ozonosondes, dades de satèl.lit, climatologies i campanyes d’aeronaus. És la primera vegada que la química en fase gasosa de l’NMMB/BSC-CTM s’avalua a escala global i regional durant un any complet. Respecte l’evaluació del model a nivell regional, vam tenir l’oportunitat de participar en el projecte de l’Air Quality Model Evaluation International Initiative (AQMEII) Phase2. L’objectiu principal d’aquest projecte és la intercomparació de models online a escala regional sobre l’Amèrica del Nord i Europa. El nostre grup va participar en aquesta iniciativa sobre el domini europeu utilitzant el model NMMB/BSC-CTM. L’avaluació del model mostra una bona avinença amb les observacions. En general, els resultats del model es corresponen amb l’estat de l’art dels AQMS a escala regional i global.