TECHNOLOGY OF MATERIALS

Author: LISTE CARMUEJA SARA.
Year: 2003.
University: VIGO [More theses of this university] [www.uvigo.es].
Place of defense: ESCUELA TÉCNICA SUPERIOR DE INGENIEROS INDUSTRIALES.
Place of preparation: ESCUELA TÉCNICA SUPERIOR DE INGENIEROS INDUSTRIALES.

Summary: This research paper focuses on the study of bioactive glasses based on a matrix of silica, with potential biomedical applications, both denatales as orthopedic, and obtaining coatings using the technique of laser ablation (PLD). This study has been made sparalelos of the structure, morphology and composition of the glass volúmicos and its related coatings using dee various techniques caracterización.Además have conducted tests bioactivity through immersion in simulated body fluid (SBF) and biocompatibility by cultured cell. With regard to studies in glasses volúmicos identified different bandasasociadas the functional groups Si-O-Si both enlazantes as not enlazants, being able to differentiate between groups with a (1NBO) or two oxígenos not enlazantes (2NBO) tetraedro.Particularmente it was demonstrated that the presence of groups 2NBO play a very important role in the rate of dissolution through the formation of groups silanol on the surface of glass and the incorporation of water. As for the process itself laser ablation was carried out a systematic study to determine the optimum processing parameters, namely energy laser, substrate temperature and atmosphere utilizada.Así also made a minucioiso comparative study of carcteristicas compositional and structural between white and layer obtained from the same. The in vitro tests conducted volúmicos have demonstrated the existence of a relationship between the quantity and type of functional groups and the growth of the different layers that arise how consequence of the process bioactivo.En As for the coatings, these same tests revealed a critical thickness at which the process bioactivo develops in a similar fashion regardless of the substrate used. Finally biocompatibility studies performed by cultured cells show that in terms of citoxicidad both glasses volúmicos as coatings obtained by PLD does not affect the activity celular.Con regard to the cellular activity is emphasized that the behavior of glass bioactivo used these trials are almost the same as that presented by the reference materials.

Author: PEREIRO LÓPEZ GABRIEL.
Year: 2004.
University: SANTIAGO DE COMPOSTELA [More theses of this university] [www.usc.es].
Place of defense: ESCUELA UNIVERSITARIA DE ÓPTICA Y OPTOMETRÍA.
Place of preparation: INSTITUTO DE CERÁMICA DE GALICIA.

Summary: In this paper, new ceramic materials are manufactured "unconventional" field focused on constructive (materials that provide a good thermal insulation, which solves problems fitting acoustic building, etc.) They have used various techniques such as casting processing barbotinas and pressed with small amounts of various aglomerantes (silicates, cements inorganic resins.) Furthermore, as a second goal, it raised the possibility of leaving, for the manufacture of these products, waste abundant in the autonomous region of Galicia and mixed origins (Waste Industries Conserveras, Waste Carpinterías Metallic, Forest Waste, Waste Industries Agroalimentarias, etc.), thereby reutilizaban materials (mostly waste) increasing its value añadido.En cases where it was not possible from a residue (either because the product characteristics sought so advised) using the raw material of mineral origin (vermiculitas, kaolin, ..) most appropriate in each case. Specifically, in response to "criteria functionality," OBTAINING AND CONSTRUCTION OF NEW MATERIALS FOR CONSTRUCTION IS CENTER IN THREE AREAS:-Insulation Materials with certain thermal properties and / or acoustic, focusing primarily to the acquisition of barriers térmicas.Destacan septa light vermiculite boards microsílice and expanded clay, as well as panels of mussel shells. - Absorbent Acústicos providing new solutions for packaging acústico.Se included in this chapter: sponge-porous ceramics open (with a high sound absorption and fire-retardant properties) and a range of absorbent acoustic consisted of a dispersed phase of vegetable fibers or shell nuts. - Active Materials: Where, left a mineral (expanded vermiculite) and waste metal (aluminum chips), was obtained insulating material that is suitable for use as electrical sensor on pillars, and so on. Moreover, in response to the "Nature of raw materials employed," has worked on two major groups of materials:-Mineral Materials Source: Based on mussel shells of silica fume, and minerals as such as kaolin and, clay or vermiculitas expanded. - Materials Plant Origin: Using fiber obtained from oropendolas, ferns, straw, pine needles ... and, shells of sunflower seeds and peanuts: We collected, therefore, new products, alternative to the existing ones on the market or substitutes therefor; detalléndose in memory of this thesis describing how they obtained each and every one of these new materials and their possible use.

Author: DAVÓ GUTIÉRREZ M. BELÉN.
Year: 2004.
University: COMPLUTENSE DE MADRID [More theses of this university] [www.ucm.es].
Place of defense: FACULTAD DE CIENCIAS QUÍMICAS.
Place of preparation: CENTRO NACIONAL DE INVESTIGACIONES METALÚRGICAS (CENIM/CSIC).

Summary: One of the challenges with more emphasis pursued over the past years, the aerospace industry is the development of structural materials that ligeren weight of the aircraft and, in turn, have high mechanical strength and corrosion face. Alloys Al-Li, which include alloy commercial 8090, achieve a significant reduction in the weight of the structures of high resistance of the series 7xxx. Since these structural materials will work in aggressive atmospheres, not only must meet mechanical requirements, but must submit high resistance to corrosion (intragranular, peeling, etc.). Under stress and corrosion. Still, it is essential to protect the aluminum alloys using effective methods to prolong the condition of the structures without representing a safety hazard. For several decades, the aviation industry applies surface treatments that are based on the ability inhibodira of chromates. Since these substances are highly toxic, for several years their use is very limited. For this reason, have intensified investigations that are trying to find alternatives "free of chromium," efficacy comparable to the cromtaos but environmentally acceptable. In this contexo focuses on the present report which has been characterized for the first time and from the point of view of corrosion, a new light alloy d Al-Cu-Li reaching the mechanical properties of alloys high resistance the series 7xxx. This has been studied using electrochemical techniques in different ways of aggressiveness in order to define the mechanisms governing the process of corrosion. It has put special attention to corrosion phenomenon under tension, of great importance in the aviation industry, leading to the conclusion that its resistance to this phenomenon is superior to other alloys conventional (7075) or the same family (8090). Finally, it has studied the use of cerium and lanthanum salts as corrosion inhibitors environmentally acceptable and possible substitutes for chromates. The results found are encouraging and open up new avenues for application of the salts lantánidas.

Author: BAILE PUIG MARIA TERESA.
Year: 2004.
University: POLITÉCNICA DE CATALUÑA [More theses of this university] [www.upc.edu].
Place of defense: Aula Màster. E.P.S. d'Eng. de Vilanova.
Place of preparation: ETSEIB, PAVELLÓ E Campus SUD.

Summary: We review the background and the state of art in the formation of aluminum alloys in semisolid state. It describes the various processes, their advantages and disadvantages and its industrial interest according to available information. It raises the theoretical aspects of conformation in semisolid state-related: rheological properties tixotrópicas and of the materials, the mechanisms of formation of sludge; structure of the ingots, and the effects of warming and the heat treatments. By techniques Thixocasting were manufactured with alloy A357 and A356, different pieces: ingot, semicomponente and components for car and motorcycle. These materials are studying the effect of heat treatment on the microstructure, mechanical properties and fracture mechanisms. The experiments conducted to determine the effect of temperature on the rate and mechanism of growth of silicon, the evolution of the phase and intermetallic compounds, and the more or less heterogeneous distribution of magnesium. Likewise, the production of semicomponentes in different conditions, through a comprehensive control of manufacturing conditions, has allowed optimize production parameters through statistical procedures. We are studying the mechanisms of corrosion in saline solutions in different materials, through tests in salt spray chamber, and measures impedance techniques polarization. Finally is a comparative study of the results obtained with components manufactured by Thixocasting by other processes of state formation in semisolid (New Rheocasting and U Liquidus Casting) and by conventional methods, stressing the advantages and disadvantages of new technologies.

Author: PEREZ COLL DOMINGO.
Year: 2005.
University: LA LAGUNA [More theses of this university] [www.ull.es].
Place of defense: FACULTAD DE FARMACIA.
Place of preparation: FACULTAD DE FARMACIA.

Summary: The main objective of this research work has been the study of materials based on ceria, especially as it relates to electrochemical characterization of the same, its potential for application in fuel cells solid oxide (SOFC). We analyzed the effect produced by the various doped with trivalent cation (Ln3 +) in the crystalline network of CeO2, leading to the solid solution Ce1-xLnxO2-x / 2, with x = 0, 0.05, 0.1, 0.2, 0.3 and Ln = Y, Gd, Sm. The. Ions aliovalentes with the lower oxidation state of Ce4 + generate oxygen vacancies, which occur as a result of an increase in the concentration of "carriers" of the ionic load. The materials have been prepared to study mainly by the method of "freeze-drying", which is based on obtaining a precursor amorphous from dehydration by sublimation dissolution of a frozen metal salts. The crystalline phases are obtained after precalcinación of these precursors to temperatures as low as 375Â ° C, thereby materials with grain nanometric. In some cases, they have used materials business (Rhodia), and other preparations as precursor obtained by the method acetil-acetona, with the goal of being able to compare the effects of the type of preparatory. To facilitate the sintering have added small amounts of Co as an additive on the material in powder form. Samples were without Co. sinterizaron to 1500-1600Â ° C, while the samples with Co were synthesized at 1000, 1150 and 1500Â ° C. The effect of Co in the process of densification depend heavily on the temperature sintering. The degree of desnificación of samples with sintered Co. to the lowest temperatures was similar to the show without Co.. The study of the properties of ion transport in conditions of normal pressure (pO2 = 0.11 atm) is done via spectroscopy complex impedances, and may discriminate between the different contributions that affect the process of driving the total. Three contributions were appreciated and fundamental: one associated with the process of driving inside the grain (bulk), another associated with the process of driving limit of grain, and other associated with the transfer of ca rga between the material and the electrode. The temperature and time tuning and the use of various doping (Ln3 +) and additives (Co, SiO2), produce noticeable changes in the microstructural properties, which are related to the macroscopic effects and specific processes driving. It analyzes the effect is produced by varying the amount of trivalent dopante driving on the properties of the grain boundary and grain. The process of driving associated with the interior of the grain is highly dependent on the interaction between oxygen vacancies and the grain boundary. The process of driving associated with the interior of the grain is highly dependent on the interaction between oxygen vacancies and trivalent dopante own. An increase in the initial concentration of dopante produces a clear increase in the interaction of defects, which has resulted in a clear reduction in grain conductivity at low temperatures. Moreover, the process of driving the limit grain depends heavily on the amount of dopante that segregue in the same adjust their behavior so well suited to the "Model Layer charges Space." Unlike in the case of grain, an increase of the amount of dopante resulted in a decline in effect blocking associated with the grain boundary, due to the potential cargo space decreases considerably. Also, the type of dopante used decisively influences on the properties of ion transport of cargo. The introduction of different cations has allowed us to study the effect of radio inónico in such properties. The relaxation of tensions caused by the introduction in the network of fluorite crystal, cation "older" that the original cation results in a to 8 umento d 1c32 and transport properties. It analyzes the relationship between ionic radius and the interaction of defects, which have a decisive influence on the grain conductivity of the material. Also relacionaremos the process of grain boundary with the effect produced by different cationic rays in the space of potential charges. The effect of Co in the driving properties are studied carefully, taking special account of the properties associated with the grain boundary. The drop in temperature sintering in the samples with Co produces major changes in the microstructure which affect the macroscopic effects d driving. In turn, that temperature sintering is manifested crucial in retaining sufficient additive in the grain boundary, thus varying the effect both in the sintering and in the transport processes. Samples with sufficient Co. on the edge of grain sufrewn a clear decrease in resistivity associated with that process. It questioned the possible effect of removal on the impurities of SiO2, often in the scientific literature is attributed to the addition and Co., and ynos prefer for a lowering effect of the potential of space charge layer. The extrinsic and controlled introduction of impurities of SiO2 has enabled us to analyze the effect that they produce in the process of driving associated with the grain boundary, both macroscopic and specific level. By co-adición Co on these samples "contaminated" study the possible cleaning the impurities in obtaining better conductivity of grain boundary. It examines the process of polarization of the electrodes. Samples with a limit of grain more resistive present values of polarization higher, which reduces significantly with the addition of Co. The decrease in the sintering temperature of the samples with Co., produces a clear decrease in polarization, which allows us to correlate the efficiency of the process of transferring the burden with the amount of C present in the vicinity of the grain boundary. The materials under study are subject to stringent conditions for the reduction and explores the loss of estequiometría of them. The number and radius of cationic dopante relate to the effect of reduction occurred. The tensions produced in the structures, as well as the balance between vacancies and the partial pressure of oxygen is essential in the analysis process. The reduction process produces an increase in the concentration of electronic carriers, which leads therefore to an increase in electronic conductivity. We have studied the effect of the amount and type of doping trivalent in the electronic transport properties, the results of which relate to the values obtained from reducibilidad. This allows us to identify the importance of cation radius and the initial concentration of dopante in conductivity. It deducted the values of mobility that we confirm electronic transport type "hopping". It was also revealed that the process of electronic transport is strongly influenced by the degree of reduction materials and not by the mobility of carriers. Samples with a higher degree of reduction will be the presenting some higher values of electronic conductivity. Adding Co. have a critical bearing on the process of transporting mail when materials are subjected to reductive conditions. It produces a different effect depending on the type of dopante used, which may indicate an interaction with the additive dopante Co.. The temperature sintering is manifested crucial in determining the effect produced by Co, revealing the importance of the amount of Co in the grain boundary, the effect that occurs in the electronic conductivity. These considerations suggest that we limit grain participates actively in the process of transporting mail. The electronic properties are analyzed in terms of the characteristic parameters involved in operating conditions in a SOFC. It is reviewing cases in which fuel is hydrogen and methane. The use of each will produce different degrees of conversion along the surface of the anode material. As a result, the material presents different levels of electronic conductivity, which can produce significant thermal variations along the same. The oxygen permeability in moderately oxidizing conditions allows us to study the electronic conductivity type P. As in the electronic conductivity type No, the amount and type of dopante added influence on the results of permeability obtained. A higher concentration of oxygen vacancies initial favors the process for driving holes, which resulted in a strong increase in conductiviad type pa average concentration dopante increases. In turn, the samples dopadas with Sm have a p type conductivity higher than that of samples with Gd. In this aspect, the interaction defects can be critical to explain this kind of behavior. It looks, too, the effect of the addition of Co on the driving type p, whose results depend on the type of dopante and quantity of the same, which suggests an interaction between the latter with the additive Co.. Because of this, everything seems to indicate that the limit grain contributes significantly to the electronic conductivity type P. The addition of Co on samples of ceria dopadas produces opposite effects on the electronic kind conductividades ny type P. Finally, the combination of various techniques electroquímias has enabled us to obtain an estimate of the ionic conductivity in reductive terms. Knowledge of the total conductivity and the electronic component depending on the partial pressure of oxygen, we can deduce the ionic conductivity in a wide range of oxygen partial pressure. The results, we suggest the possibility of an increase in the same conditions to move towards reductive. Confirmation of these results could change the current optical materials based on ceria Doped, because the number of ion transport is much higher than generally assumed in reductive terms.

Author: PÉREZ MARIANO JORDI.
Year: 2005.
University: RAMÓN LLULL [More theses of this university] [www.url.edu].
Place of defense: ESCUELA TÉCNICA SUPERIOR IQS.
Place of preparation: ESCUELA TÉCNICA SUPERIOR IQS.

Summary: It has studied the deposition of several metallic and ceramic coatings on steel by the chemical vapor phase deposition reactor fluidised bed (FBR-CVD). Coatings have been obtained by diffusion of Si and Cr in beds of metallic particles through the on-site generation of precursors by reaction with HCI. The diffusion of Si and nitriding (siliconitruración) has been made in reactors double bed: a fixed bed of metal particles and a fluidised bed of alumina particles. There were two types of coatings deposited ceramic, silicon nitride (SiNx) and titanium nitride, by the reaction of the precursor (SiCl4 and TiCl4) with NH3 in beds of inert particles. It has developed techniques FBR-CVD for the deposition of TiN coatings based on advanced, higher hardness and better resistance to oxidation that TiN coatings. On the one hand, multilayers in which layers of TiN have alternated with layers of TaNx or SiNx have been deposited with frequencies in the range nanmétrico. Moreover, the codeposición of TiN and SiNx has been optimized to obtain coatings composed of composite materials at the nano-scale. Besides experiments FBR-CVD, has conducted a study of CVD: the synthesis of nanowires of silicon on various substrates with another through growth vapor-líquido-sólido.

Author: CORBELLA ROCA CARLES.
Year: 2005.
University: BARCELONA [More theses of this university] [www.ub.es].
Place of defense: FACULTAD DE FÍSICA.
Place of preparation: FACULTAD DE FÍSICA.

Summary: This thesis presents a study of the synthesis and characterization of amorphous carbon (DLC) type diamond thin film prepared. This material is notable for displaying a high hardness, low friction and good wear resistance. Thanks to their excellent mechanical and tribological properties, the DLC has numerous applications such as protective coatings and solid lubricant. As examples, we can mention the coating of cutting tools, computer hard discs and orthopedic appliances. The most common techniques for the deposition of DLC are the chemical vapor phase deposition activated plasma (PECVD), cathodic arc, and cathodic spraying. A major disadvantage by the layers of DLC in his effort high compressive residual factor limiting the thickness of the layers to a few tens of nanometers. Overcoming this thickness causes instabilities in the material which lead to problems including accession to the tion of the layer. The literature suggests several solutions to reduce internal tensions of the DLC and thus lower mechanical this effort, such as the deposition of layers of metal anchor and repetitive structures in the nano multilayer period. The aim of this thesis has been to prepare different structures DLC and modify their properties by changing the technological parameters of deposit. Analysis of the results of characterization of the samples have provided us with its structure, morphology, chemical, optical, electrical and surface. Part of this work focuses on the growth of the DLC techniques PECVD through a source pulsasda-DC canned power that fuels a plasma methane. This technology offers several advantages, such as reducing the intrinsic effort of the DLC and increasing the speed of deposit, all made using a facility cheaper than traditional radio. We have studied the parameters situ plasma pressed (electronic temperature, ionic densities and electronics, and power plasma) by a Langmuir probe into resolution mode season. Thus, it has appreciated dependence of the properties of the layers on the fundamentals of the deposit. On the other hand, it has also been considered incorporating metal atoms (Mo, Nb, Ti, W) on the network using the technique of carbon deposit spray with reactive magnetron. Layers DLC with metal content, which presents a nanoestructura and crystallinity determined by the metal abundance and added, have a lesser effort thanks to a more relaxed without suffer greatly hardness. The tribological properties are also favored by showing very low values (0.03) coefficient of friction.

Author: DOSTA PARRAS SERGI.
Year: 2005.
University: BARCELONA [More theses of this university] [www.ub.es].
Place of defense: FACULTAD DE FÍSICA Y QUÍMICA (UNIVERSIDAD DE BARCELONA).
Place of preparation: FACULTAD DE QUÍMICA (UNIVERSIDAD DE BARCELONA).

Summary: The ultimate goal of this dissertation is to improve the properties obtained for coatings WC-Co without an excessive increase in the cost of production through the introduction in the process of new types of dust micro-nanoestructurados. To that end, the objectives set prior to the realization of this thesis were: * The search and retrieval on the market of new nanostructured powders viable for the thermal projection. * The complete structural characterization of powders micro-nanoestructurados obtained. * Optimizing conditions projection by monitoring of particles in the air to reduce the sharp decay suffered by this new type of dust during the process of projection. * The characterization of new estructuras-propiedades obtained coatings micro-nanoestructurados well as its comparison with a reference system microestructurado. * The evaluation of the improvement in the technological properties of the coatings thermal projection from these new powders heading micro-nanoestructurados.

Author: GAMEZ PEREZ JOSE.
Year: 2005.
University: POLITÉCNICA DE CATALUÑA [More theses of this university] [www.upc.edu].
Place of defense: sala de conferències de l'ETSEIAT.
Place of preparation: ETSEIB, PAVELLÓ E Campus SUD.

Summary: This thesis analyzes the structure and induced morphology of sheet and thin plaques obtained by different transformation processes. The sheets and plaques were prepared in different thickness using four polypropylene â based materials: an isopolypropylene homopolymer and three ethylene-propylene block copolymers (EPBC) with different ethylene content. The transformation processes used to prepare the sheets and plaques were the following: injection moulding (thicknes of 1, 2 and 3 mm), extrusion â calendering (thickness of 0.5 and 1 mm) and compression molding (thickness of 1 and 2 mm). Some injected plaques and extruded sheets were also submitted to and additional annealing step in order to cause morphological changes and a more homogeneus structure. The structural and morpholigical charachteristics were evaluated by polarized light microscopy (MLP), differential scanning calorimetry (DSC) and wide angle x-ray scattering (WAXS). The mechanical properties of the sheets and plaques were determined with normalized tensile tests, performed parallel to the melt flow and transverse directions (MD and TD, respectively). The fracture properties were evaluated using the post-yielding fracture mechanics, which best describes the fracture behaviour of plastic film and thin sheets, with the essential work of fracture (EWF) technique. The fractured surfaces were observed with scanning electron microscopy (SEM). The discussion of the experimental results is focused in investigating the structure â properties relationships in both testing directions (MD and TD), as a function of the following variables: transformation process, material (ethylene content), annealing treatment and thickness. It is concluded that those variables affect to four processing parameters (cooling rate, shear stress, rheological behaviour and crystallization) which are responsible for the processing induced morphologies and, therefore, for the final mechanical and fracture properties. Additionally, different multilayered systems (composed of two or three layers) combining the above mentioned materials were prepared by plane coextrusion, being the total thickness of the system equal to 0.5 mm. The structure of such systems was analyzed using MLP and WAXS. The tensile properties were evaluated, standing out the applicability of the EWF method to evaluate the fracture behaviour in some systems. It is proposed some prerequisites that the multilayered systems should fulfil so the EWF method can be applied to describe properly the fracture properties

Author: BOU SOLSONA ENCARNACIÓN.
Year: 2005.
University: JAUME I DE CASTELLON [More theses of this university] [www.uji.es].
Place of defense: INSTITUTO DE TECNOLOGIA CERAMICA.
Place of preparation: ESCUELA SUPERIOR DE TECNOLOGÍA Y CIENCIAS EXPERIMENTALES.

Summary: The supply of zircon sand is creating a situation of uncertainty in the industrial sector manufacturing ceramic tile, due to its progressive and costly production inadequate. In this paper we study the possibility of reducing or eliminating the use of zircon in compositions slipped and fried, which is used as raw material because it provides whiteness and opacity, slipped layers and glazes obtained from frits. It has been determined that the use of alumina as feedstock in engobes reduces their content in zircon. In the case of chips, the addition of phosphorus pentoxide to its composition makes it possible to reduce the amount of zircon used in its preparation. Finally, it has obtained fried, zirconium, based on the system SiO2-CaO-TiO2. In all three cases it has conducted a micro-structural study in order to determine which are the causes that allow the reduction or elimination of zircon without producing a deterioration of whiteness and opacity of layers slipped and the glazed .

Author: MARRERO LÓPEZ DAVID.
Year: 2005.
University: LA LAGUNA [More theses of this university] [www.ull.es].
Place of defense: FACULTAD DE FARMACIA.
Place of preparation: LA LAGUNA.

Summary: This thesis has focused on the characterization of materials belonging to the family of drivers ion oxide LAMOX (series of compounds derived from La2Mo2O9). The main aim has been to study the feasibility of such materials as potential electrolytes in batteries solid oxide fuel, which has paid special attention to the synthesis of materials, structure, microstructure, stable reductive conditions, and finally, the properties of transport. Different doping have been introduced in the structure, La2-xAXMo2-yByO9 (A = Ca2 +, Sr2 +, Ba2 +, K + and rare earths, B = W6 +, Nb5 +, Cr6 +), in order to stabilize the polimorfo- high temperature, which require a detailed analysis of the effect of these substituents on the structure, the transition phase and the transport properties. All these materials were characterized by X-ray diffraction to determine the structure and solubility limit of different doping; by electron diffraction and high-resolution images, to investigate the microstructure and solubility limit of different doping; by electron diffraction and high-resolution images, to investigate the microstructure, and by other techniques, such as scanning electron microscopy, thermal analysis (TG / DTA, DSC, MRI) and spectroscopy fotoelectrónica X-ray. The electrical characterization has been carried out with a wide variety of techniques such as spectroscopy impedances, ion-blocking, electromotive force, permeability, etc.. With regard to the synthesis of materials, have used different methods, most of them based precursors, in order to optimize the microstructure and properties of transport methods of sol-gel citrate, acetlacetonato, coprecipitación lyophilization amended, in addition to the conventional ceramic method. One of the most promising substituents in these materials is the W6 +. The replacement of Mo6 + by W6 + is possible up to 75% while retaining the train and no significant changes in the conductivity of the total, with values between 0.04 and 0.08 S.cm-1 to 973 K higher than values rather parala zirconia Doped Y3 + to the same temperature and comparable to those of ceria and galato lanthanum doped. The main advantage provided by W in the structure La2Mo2O9 is the increase in the range of stability in reductive terms, avoiding even the depreciation of the material. Finally, it has developed a new method based on sol-gel and combined with the use of polymeric spheres as molds for the preparation of materials with uniform porosity, which has been applied first to obtain thin films of La2Mo2O9 microporosas and Secondly for the preparation of different electrode materials. The materials obtained in this way have been characterized by surface techniques (Adsorption gas porosimetría mercury, etc..). La alta porosidad de estos materiales y alta superficie específica BET, les puede hacer potencialmente útiles en aplicaciones que requieran la difusión de reactivos, como por ejemplo; aplicaciones catalíticas o electrodos para pilas de combustible SOFCs.

Author: GUILLEN GRIMA MARIA DEL CARMEN.
Year: 2005.
University: PÚBLICA DE NAVARRA [More theses of this university] [www.unavarra.es].
Place of preparation: UNIVERSIDAD PÚBLICA DE NAVARRA.

Summary: Through a random sampling cluster or clusters were selected 1048 students from Navarre and 903 in the region. The questionnaire consists of six blocks of background questions, current health status and past physical activity, dietary habits and social sexuality. The questionnaire was developed and validated by Aguinaga (1993) with students from Navarre and Murcia. In Navarre used three versions in Spanish, Basque and bilingà ¼ e. We calculated the Quetelet index, consumption of pure alcohol in grams per day. From questions about physical exercise, calculated the index of physical activity (IAF) in Kilocalorías a week and METs-minute consumed in a week time. A 29.3% of students have bajopeso, while a 10.3% are overweight. Overweight is more common in men than in women 21.3% vs. 3.5%. By contrast the bajopeso is more common in women than in men with a 41.7% and 9.3% respectively. There are differences between Navarre and Murcia in the degree of adherence to the Mediterranean diet, being higher in Navarre with an average of 45.1% in Murcia with a 43.9%. There are no differences between males and females in the degree of adherence to the Mediterranean diet. The students' diet is characterized by a high consumption of cakes, candies and sausages, as well as a low consumption of vegetables, salads and fruits. A 32% of students consumed cakes, biscuits and sweets every day, a 30% sausages consumed daily. Only 20.3% of students consumed three or more servings of fruit a day, the proportion of students who consume 3 or more daily servings of vegetables and salads is further reduced by 5.2%. Between 1993 and 1998 there has been an increase in the consumption of marijuana while at the Public University of Navarra, as in Murcia. The proportion of students who have used marijuana sometime in their lives at the Public University of Navarra has risen from a 41.8% to 51.9% in 10998, while in Murcia has risen from 25.8% to 34.8%. It has also increased consumption sporadic, the daily, and on weekends in both places.

Author: PÉREZ BRAVO MARÍA DEL CARMEN.
Year: 2005.
University: PAÍS VASCO [More theses of this university] [www.ehu.es].
Place of defense: FACULTAD DE CIENCIA Y TECNOLOGÍA.
Place of preparation: FACULTAD DE CIENCIA Y TECNOLOGIA.

Summary: The main objective of this work is to study and microstructural optimization of a new family of alloys: aluminuros titanium, with the ultimate purpose of its possible application in the aviation sector. These materials have a big advantage for use in aeronautics and is its low density, about half the show that the alloys used in the production of components for engines of the aircraft. Moreover, its good mechanical properties at temperatures cans, make them prime candidates to replace the type of alloys used at present in this area. However, considered this remarkable advantage, aluminuros titanium have a major drawback, low ductility at room temperature, which makes it very difficult to manufacture, handling and assembly of components. In this type of material, the mechanical properties are very sensitive to the type of microstructure, so modify their properties to get an adequate design microstructural. Achieving this objective through simple trial is also a challenge in the face of possible industrialization of the same. In this work we have therefore developed a number of fine grained microstructures, very promising in terms of improving the properties covered by the application of heat treatments only in two stages. About these new microstructures has made a deep study of genetic transformation mechanisms involved in their formation, leading to propose new training sequences, leading to propose new training sequences, which they explain all of the new structural features found.

Author: SANTOFIMIA NAVARRO MARÍA JESÚS.
Year: 2005.
University: COMPLUTENSE DE MADRID [More theses of this university] [www.ucm.es].
Place of defense: FACULTAD DE CIENCIAS FÍSICAS.
Place of preparation: CENTRO NACIONAL DE INVESTIGACIONES METALÚRGICAS (CENIM CSIC) MADRID.

Summary: Among all of phase transformations that can take place in a steel processing bainítica has emerged as one of the most interesting and controversial. For in-depth knowledge and understanding of this transformation, in Chapter 1 has been developed as a comprehensive introduction of phase transformations in solid form in steel, and in particular the characteristics of the transformation bainítica. Their interest is not purely scientific, but also industry. Indeed, the addition of alloy elements such as silicon, I could give rise to microstructures bainíticas without formation of carbides, and precise knowledge of the influence of other different alloy, will get in this new type of steel with a combination of resistance properties tenacity and very attractive. The optimization of thermal treatments more appropriate for obtaining such microstructures requires an exhaustive study of the kinetics of the transformation bainítica. This study is carried out in Chapter II, which also proposes a new model to predict the kinetics of the transformation bainítica. In this model distinguishes between bainita formed through nucelación and subunits directly in edge of austenitic grain and from subunits previously formed. Certainly, this model represents one of the most interesting scientific contributions in this thesis for its direct contribution to the understanding of the transformation bainítica. All the knowledge acquired in Chapters I and II are employed in Chapter III for the design of new steels bainíticos rich in silicon with high resistance properties and tenacity. In this paper, thesis has developed the theoretical background necessary to be able to deal successfully with the design of new steels abiníticos free carbides, with a wide variety of diferntes possibilities alloy can achieve transformation kinetics and microstructural characteristics similar and be prosecuted through treatments termomecánicos large industrial application. The procedure covers design, in this way, both the choice of the most suitable chemical compositions as treatments termomecánicos more appropriate for obtaining the desired microstructures. After presenting in Chapter IV material obtained after processing industry and explain the experimental procedure to develop, Chapter V is the caracterizaicón of steels designed. This characterization, both microstructural and mechanical properties, reveals that steels designed far outweigh the expectations placed in them. In Chapter VI is conducting a study of the kinetics of isothermal three steels designed. This study was used in this chapter, together with other experimental results found in the literature, for the validation of the new model proposed in Chapter II for the kinetics of the transformation bainítica. It is found that this model predicts an excellent approximation of the volume fraction of bainita formed in all the steels studied.

Author: Gonzalo Ruiz Javier.
Year: 2006.
University: AUTÓNOMA DE BARCELONA [More theses of this university] [www.uab.es].
Place of defense: Institut de Microelectrònica.
Place of preparation: Institut de Microelectrònica de Barcelona.

Summary: The Spanish food industry has reached a high level of maturity and modernization adapting to the changing environment and consumption patterns. This has come to become the first industry in the country and a highly strategic component of the Spanish industry. The innovation and development of the food industry move from generic form of two main routes: the safety and quality of food. The increasing complexity of the food chain requires, on the other hand, the development of effective traceability systems to ensure the soundness of every link. The biosensor technology has experienced remarkable progress in recent years, due largely to the development of devices applied to the area of biomedicine. These technologies in advanced stages of maturity have been gradually transferred horizontally to other sectors such as the environment, and more to emerging food products. The most notable features of these devices that make them highly attractive options to compete in the agri-food market with other technologies is its specificity, high sensitivity, his short-time analysis, capacity for inclusion in integrated systems, ease of automation, its ability to work in real time, his versatility that allows the design of devices to the letter, and its low cost, among others. In the construction of integrated systems paid special relevance techniques fotolitográficas ( "thin film") and serigraph (thick film). Example, the work presented here includes among its objectives with the design, production and characterization of miniaturized transducers , which will draw on these technologies microfabrication devices that provide small, uniform and well defined geometrically, which ensures reproducibility of the partially built sensors. use of microelectronic technology is widely used in the development of new sensors . Chapter IV describes the manufacturing processes of different chips, whose configuration is based on various provisions of three electrodes, labor, counter electrode and reference, as well as electrochemical characterization of the same. Thanks to the best benefits of substrates silicon and the low cost of its production, becoming more microsystems incorporates a wide variety of products and industrial processes. While technology serigráfica based on the deposition of conductive ink on an inert carrier, does not permit the manufacture of transducers so small size as its predecessors, does not require special manufacturing conditions as rigorously controlled, which makes it more accessible. manufacture of devices based on configurations similar to those described earlier in the course of chapter V, as well as its characterization. Special attention in these stages of manufacture deserves the reference electrode. Whereas in the models serigráficos this electrode is defined by the deposition of a layer of Ag / AgCl, the fotolitográficos integration is not so trivial. example, in chapter VI presents different alternatives for the development of this electrode, including a design that combines the two technologies. once described the stage of manufacture of sensors, the following chapters focus on its use in the manufacture of highly selective biosensors of various analytes interest in the food industry, even in complex samples. protocol construction of different biosensors are common stages that are further subdivided in others, depending on the type of transducer and / or type of application. immobilization of biological component the first of these steps common, and possibly the strongest impact on the operation of the biosensor. below 8 n, p 88f one will show its worth through studies reproducibility, repeatability, time for life detection limit , and so on. in the conditions of experimental variables that influence the electrochemical response, optimized through the methodology of designing experiments. While the development and characterization of an analytical method is important in itself, its interest would if it were not limited capable of being applied to solving any real problem. Eventually, the viability of the methods set up shall be verified by their application in samples of musts or wine, depending on the availability of the same. Chapter VII it is proposed the construction of biosensors for the determination of glucose in synthetic samples as musts. This inmovilizan enzymes Horse radish peroxidase and glucose oxidase on a chip platinum in a polymer matrix. Similarly, the chapter incorporates implementation of a biosensor bienzimático, combining alcohol oxidase enzymes and Horse radish peroxidase, for the analysis of synthetic samples and alcohol in wine. Certainly, the screen printing becomes more important in the manufacture of disposable devices, which are those that finally presented in chapter IX. Once immobilized enzymes Horse radish peroxidase and glucose oxidase through intersecting with gluteraldehido and characterized biosensors are applied to the quantification of glucose musts.

Author: GIMENO FABRA LLUIS.
Year: 2006.
University: POLITÉCNICA DE CATALUÑA [More theses of this university] [www.upc.edu].
Place of defense: AULA 28.8 DE ETSEIB.
Place of preparation: ETSEIB, PAVELLÓ E Campus SUD.

Author: SERGIO CICERO GONZALEZ.
Year: 2006.
University: CANTABRIA [More theses of this university] [www.unican.es].
Place of defense: E.T.S. DE INGENIEROS DE C.C.P..
Place of preparation: ESCUELA TECNICA SUPERIOR DE INGENIEROS DE CAMINOS, CANALES Y PUERTOS.

Summary: The thesis discusses the various sources of loss of containment at the level of application of the load, determines the relationship between them and poses a metdología assessment situations where there are combinations thereof simultaneously. This makes it possible to reduce the conservatism of the analysis and make predictions of the mechanisms of cleavage realistic physics. Make an experimental validation of model types of defects combined with state of the material (from 'Upper Shellf' up 'Lower Shelf', demonstrating the validity and security of the results obtained.

Author: NIETO HIERRO JUAN.
Year: 2006.
University: COMPLUTENSE DE MADRID [More theses of this university] [www.ucm.es].
Place of defense: FACULTAD DE CIENCIAS QUÍMICAS.
Place of preparation: FACULTAD DE CIENCIAS QUÍMICAS.

Summary: It has conducted a study of systems of waste incineration and corrosion processes occurring in such systems. Specifically corrosion of metallic materials, which are used in incineration plants, in the presence of molten salt. Such processes corrosion has been monitored by the technique of electrochemical impedance spectroscopy. To carry out this monitoring has developed an electrochemical system that simulates the process of corrosion in molten salts of an incineration plant. Moreover surface coatings have been applied to various materials by chemical deposition technique vapor in fluidized bed reactor (CVD-FBR) in order to validate such coatings in the incineration systems.

Author: COLINA BRITO MÓNICA.
Year: 2006.
University: BARCELONA [More theses of this university] [www.ub.es].
Place of defense: UNIVERSIDAD DE BARCELONA.
Place of preparation: UNIVERSIDAD DE BARCELONA.

Summary: The laser-induced transfer (LIFT) is a technique of writing directly initially developed for depositing inorganic materials from thin layers solid. The material transfer is predepositado in the form of a thin layer on a support level transparent to laser radiation. The laser pulse is focused in the intercara between this material and its medium. The interaction of pulse with the material produces its vaporization. The steam travels to the substrate where recondenses receiver. The substrate is placed parallel to the layer of material to transfer to a distance of the order of tens of microns. The use of this technique was extended to the transfer of materials in a liquid state. In this case the transfer occurs without significant phase shift of the deposited material. Because of the versatility of LIFT, it began to be used for the transfer of biomolécular solution with the aim of developing miniaturized biosensors. This thesis was developed with the following aims: first, to study the process of transferring liquids through LIFT, and the second type of biosensor or develop fully functional microarray. The equipment was designed and employee transfer developed in the framework of the realization of this thesis. To carry out the transfer of liquids joined an absorbent (thin layer of titanium) between support and the transparent liquid film to be transferred. The study of the transfer was found that the volume of fluid transferred from a laser pulse has a linear dependence with the energy pulse. Exite a minimum power from which there is no transfer of liquid. In analyzing traces produced for the laser on the layer titatio during the transfer process, it was found that it was not necessary for the pulse ablacione completely coating of titanium to produce transfer. Those conditions where the footprints are cracks on the awareness (without a defined area of ablation) are precisely those that give rise to the smaller droplets and morphologically best to manufacture arrays. There is also an energy density threshold (F0), which is responsible for generating a disturbance in the liquid layer, which determines the volume of liquid eyectado per share of the laser pulse, and therefore limits the spatial resolution of the transfer process. To demonstrate the feasibility of LIFT applied to the deposit of biomolecules conducted a trial transfer of the enzyme alkaline phosphatase on a nitrocellulose membrane. We conducted a test cromogénico on enzyme transferred and the outcome was very positive indication of the conservation of enzymatic activity after the transfer process. A second test conducted to refine the results earlier, was to transfer an antigen 17kDa of the bacterium Treponema Pallidum on a substrate Nylon. The test innmuno-detección practiced on the antigen transferred indicated that it was properly placed and restrained, while retaining its immunological activity after the transfer process. Finally, it was used to develop microarrays LIFT two cDNAs different, which were hibridados with complementary sequences (labeled with a different fluorescent agent) for each cDNA transferred. The images obtained by scanning fluorescence revealed that the microarrays developed satisfactorily hybridization occurred where the cDNA was deposited. Moreover, the presence of a different color for each sequence and the lack of fluorescence in the negative control revealed selectivity in the discrimination of cDNAs of microarrays produced. The results presented in this thesis demonstrates the feasibility of LIFT for conducting microarrays of biomolecules, with a scope of the technical equivalent to the conventional techniques of printing, allowing a larger or 8 vel n 1d7 ivel of miniaturization in devices and greater versatility.

Author: MELERO LEAL MONTSERRAT.
Year: 2006.
University: CÓRDOBA [More theses of this university] [www.uco.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: FACULTAD DE CIENCIAS.

Summary: The aim of the thesis is to obtain cathode materials deposited on thin films, which are used in batteries Lithium high voltage. From a espínela which has been synthesized through ceramic and sol-gel method, type LiMn204, in which part of Mn has been replaced by transition metals in different proportions: 0.2-0.5. It was noted that the espíneal who possessed the best qualities to be used as material in lithium batteries cathode ray high voltage was LiNi0.5Mn1.504. Once our material cathode ray were performed various measures electrochemical: voltametría cyclical measures galvanostáticas and potenciostáticas, in a range of voltage 3.5-5.0V, where there have been optimized results, getting close to or even equal to the expected capabilities for such compounds. Following the espíneal was deposited by different methods, EPD, SC and SP. The purpose of depositing thin layers in the form of a deposit is to get through a process of low cost and fast.