Dissertations / Theses on the topic 'Titanium hydride'

Aluminum foam is a porous form of solid aluminum. One method of producing aluminum foam is the powder metallurgy process. Aluminum powder is mixed with a foaming agent, generally titanium hydride (TiH2), and pressed to form a compact. In the foaming process, the compact is heated and hydrogen gas is released from the agent to form bubbles within the surrounding aluminum. However, there is a significant gap between the onset of the decomposition temperature of the TiH2 (400°C) and the melting point of aluminum (660°C). The hydrogen gas evolution begins while the aluminum is still solid, creating an accumulation of gas pressure which eventually causes microfissures inside the matrix. As a result, the final structure has interconnected pores and inferior properties.
This problem may be overcome by delaying the temperature of hydrogen evolution so that it coincides with the melting point of aluminum. Coating the titanium hydride with copper or nickel can create a kinetic barrier that retards the flow of hydrogen into the surrounding matrix.
Electroless plating is a process that can be used to deposit metallic coatings on non-conductive materials. Metallic ions in solution are reduced by a suitable agent, creating a metal deposit on the substrate. The process is autocatalytic and continues until all the metallic ions are consumed.
The objective of this work was to investigate the effect of the copper and nickel coatings on the hydrogen evolution of titanium hydride powders. It was found that the metal coatings do tend to delay the temperature of gas release and that this could potentially be used to improve the foaming process.

La nucléation et la formation d'hydrures jouent un rôle important sur la durée de vie des alliages de Ti. Dans ce travail, la transformation d’hydrure en fonction de l’orientation cristalline dans le titane commercial pur est étudiée expérimentalement et théoriquement. Les deux relations d'orientation dominantes (OR) de la transformation des hydrures obtenus par une méthode de chargement électrolytique de l'hydrogène sont {0001} // {001} <12̅10> // <110> avec le plan d’interface (OR1) et {0001} // {11̅1} <12̅10> // <110> avec le plan d’interface de {101̅3} // {11̅0} (OR2). Les orientations des grains avec des plans d'interface {101̅0} ou {101̅3} parallèles à la surface de diffusion sont les plus favorables à la formation des hydrures ayant les OR1 et OR2, respectivement. Les variants d'hydrure avec un plan d'interface parallèle à la surface de diffusion sont choisis préférentiellement en raison de leur plus grande capacité d'adaptation à la déformation. L'axe c ou l'axe a parallèle à la direction de diffusion sont des orientations défavorables, en raison des interactions complexes entre les différents variants des hydrures. Les microstructures de la couche d'hydrure ont été caractérisées afin d'étudier les mécanismes d’accommodation lors de la transformation des hydrures. Des mécanismes d’accommodation plastique sont nécessaires à l'intérieur de la couche d'hydrure. Des macles d'extension {101̅2} et de contraction {112̅2} sont induits à l’interface des platelets d’hydrure OR2. Le variant de macle sélectionnée a la plus grande capacité d'accommodation de la distorsion locale lors de la nucléation des hydrures. Les macles {101̅2} sont transformées en macles {101̅1} afin de poursuivre la croissance des platelets d'hydrure. La microstructure des hydrures dans la section transversale de la couche d'hydrure a été observée. Les interactions des différentes variants d'hydrure relaxent la déformation anisotrope à l'intérieur de la couche. La paire d'hydrures intergranulaires est un autre comportement d'accommodation pendant l'hydrogénation. Ce mécanisme se forme sur des joints à faible désorientation (< 30o) et à forte désorientation (75o< θc < 85o). Les propriétés mécaniques de la surface du titane modifiée par le chargement en hydrogène a été étudiée par nanoindentation et en traction. Après l'hydrogénation, la dureté augmente tandis que le module élastique diminue en raison de la formation d'hydrures. La dureté dépendant de l'orientation de l'hydrure δ- formé après 168 h de charge est moins sensible que celle de α-Ti. La valeur HIT moyenne de l'hydrure δ est de 3.8 ± 0.3 GPa, ce qui est supérieur à la matrice de titane (2.8 ± 0.3 GPa). L’hydrure est plus dur que la matrice. En traction, la couche d'hydrure est peu déformable. Des interactions entre les dislocations et les macles se produisent pour les platelets OR2. On observe que du glissement prismatique traverse les hydrures et que les hydrures limitent la croissance et l’élargissement des macles de tension {101̅2}
Nucleation and formation of hydride precipitates are important factors on limiting the lifetime of Ti alloys. In this work, the hydride phase transformation in commercial pure titanium is thoroughly investigated by experimental and theoretically crystallographic method. The two dominant orientation relationships (ORs) of hydride transformation by the method of electrolytic hydrogen charging are {0001} //{001} <12̅10>//<110> with interface plane of {101̅0}//{11̅0} (OR1) and {0001}//{11̅1} <12̅10>//<110> with interface plane of {101̅3}//{11̅0} (OR2). The grain orientations of {101̅0} or {101̅3} interface planes parallel to the diffusion surface are most favorable for OR1 and OR2 hydride transition, respectively. The hydride variants with interface plane parallel to the diffusion surface is preferentially selected because of the highest capacity for strain accommodation. The c-axis or a-axis parallel to the diffusion direction are unfavorable orientations, due to the complicated interactions between different hydride variants. The multi-dimensional microstructures of hydride layer were characterized to investigate the accommodation mechanisms for hydride transformation. Plastic accommodation behaviors are necessary inside hydride layer. Both {101̅2} extension and {112̅2} contraction twins are induced at the interface of OR2 hydride platelets. The selected twin variant has the highest accommodation capacity for local distortion of hydride nucleation. The {101̅2} twins are transformed into {101̅1} twins in order to the further growth of hydride platelet. Hydride microstructure on the cross section of hydride layer were observed for the first time, the interactions of different hydride variants relax the anisotropic misfit strain inside hydride layer. The intergranular hydride pair is another accommodation behavior during hydrogenation, which prefer to be formed at the grain boundary with both low angle (< 30o) and high angle (75o< θc < 85o) boundaries. The mechanical property of titanium surface changed by hydrogen charging was investigated by nanoindentation tests and tensile deformation tests. After hydrogenation, the nanohardness increases while elastic modulus decreases due to the formation of hydride precipitation. The orientation dependent hardness of δ-hydride formed after 168 h charging is less sensitive than that of α-Ti. The average HIT value of δ-hydride is 3.8 ± 0.3 GPa, which is higher than titanium matrix (2.8 ± 0.3 GPa) showing the hard nature of hydride phase. During tensile deformation, hydride layer shows a poor deformability, but the interactions between dislocations and twins occur for OR2 hydride platelets: the transmissions of prismatic slips into hydride precipitations and the hindering of hydrides on the growth and thickening of {101̅2} tension twins

Thesis (Ph. D.)--University of Maryland, College Park, 2006.
Thesis research directed by: Chemistry. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.

L’utilisation constante des hydrocarbures, les émissions de dioxyde de carbone et le réchauffement climatique font l’objet d’un débat mondial sur l’énergie. L’établissement d’une économie basée sur l’hydrogène se présente comme une solution alternative efficace. Différents problèmes technologiques sont à résoudre pour parvenir à un tel système énergétique mondial tel que la production de l’hydrogène, sa livraison et son stockage. Diverses méthodes de stockage de l’hydrogène sont disponibles. Parmi celles-ci, le stockage sous forme d’hydrures métalliques représente un moyen prometteur et pratique. Dans ce contexte, les techniques de déformation mécanique appliquées aux matériaux de stockage de l’hydrogène ont connu une utilisation accrue ces dernières années. Elles permettent l’amélioration des performances de stockage de l’hydrogène de divers types d’hydrures métalliques. Le présent travail se concentre sur l’effet de la déformation mécanique induite par la technique du laminage à froid sur les propriétés d’absorption de l’hydrogène du titane de pureté commerciale Ti50A. Pour ce faire, deux principaux paramètres de traitement ont été variés et étudiés lors du laminage à froid à savoir le taux de réduction et la vitesse de laminage. Dans un premier temps, une analyse et une compréhension des microstructures de déformation induites par la technique du laminage à froid sur le titane pur avant hydrogénation a été réalisée pour les différentes conditions de traitement mécanique. Ensuite, l’étude de l’effet du laminage à froid sur la première absorption de l’hydrogène du titane a été effectuée. Les échantillons hydrogénés ont été également examinés et l’hydrure de titane formé après hydrogénation complète a été caractérisé. Les résultats obtenus ont montré une amélioration significative de la cinétique de la première absorption de l’hydrogène pour les échantillons laminés à froid comparés à l’échantillon de titane pur non traité. L’étude paramétrique effectuée sur le titane Ti50A a montré que les paramètres de traitement par laminage à froid affectent grandement la cinétique de la première hydrogénation tout en conservant la capacité maximale d’absorption de l’hydrogène. L’augmentation du taux de réduction lors du laminage à froid permet l’amélioration de la cinétique d’hydrogénation, associée à une activation de la déformation par maclage pour les faibles taux de réductions et une diminution de la taille des grains de titane après laminage. De plus, il a été montré qu’une faible vitesse de laminage assure une meilleure cinétique d’absorption d’hydrogène, tout en présentant des microstructures caractérisées par une fraction importante des joints de faibles désorientations. Finalement, le mécanisme d’absorption de l’hydrogène par le titane Ti50A a été étudié à travers la détermination de l’étape limitante de la vitesse de la réaction d’absorption. Il s’est avéré que tous les échantillons laminés dans les différentes conditions suivent le mécanisme d’absorption régi par le modèle du volume contractant. Un échantillon de titane laminé a été sélectionné pour l’étude détaillée de la transformation de phase du titane vers l’hydrure de titane suite à l’absorption complète de l’hydrogène par le Ti50A. Cette étude a été effectuée en analysant et examinant des échantillons partiellement hydrogénés
The constant use of hydrocarbons, carbon dioxide emissions and global warming are the subject of a global energy debate. Establishing a hydrogen economy is considered as an effective alternative solution. Various technological problems have to be solved to achieve such a global energy system such as hydrogen production, delivery and storage. Various methods of storing hydrogen are available. Among these, storage in the form of metal hydrides represents a promising and practical means. In this context, mechanical deformation techniques applied to hydrogen storage materials have seen increased use these recent years. These techniques enable the improvement of the hydrogen storage performance of various types of metal hydrides. The present work focuses on the effect of mechanical deformation induced by the cold rolling technique on the hydrogen absorption properties of the commercial pure titanium Ti50A. To do this, two main processing parameters were varied and studied during cold rolling, namely the reduction rate and the rolling speed. First, an analysis and an understanding of the deformation microstructures induced by the cold rolling technique on pure titanium before hydrogenation was carried out for the different mechanical processing conditions. Then, the study of the effect of cold rolling on the first hydrogen absorption of titanium was carried out. The hydrogenated samples were also examined and the titanium hydride formed after complete hydrogenation was characterized. The obtained results showed a significant improvement in the kinetics of the first hydrogen absorption for the cold-rolled samples compared to the unrolled pure titanium sample. The parametric study performed on titanium Ti50A showed that the cold rolling processing parameters greatly affect the kinetics of the first hydrogenation while maintaining the maximum hydrogen absorption capacity. The increase in the reduction rate during cold rolling allows the improvement of the hydrogenation kinetics, associated with an activation of the twinning deformation for low reduction rates and a decrease in the size of the titanium grains after rolling. On the other hand, it has been shown that a low rolling speed ensures better kinetics of hydrogen absorption, while exhibiting microstructures characterized by a large fraction of low angle boundaries. Finally, the mechanism of hydrogen absorption by titanium was investigated through the determination of the rate limiting-step of the absorption reaction. It was revealed that all rolled samples under the different conditions follow the absorption mechanism governed by the contracting volume model. In addition, a sample of rolled titanium was selected for detailed study of the phase transformation of titanium to titanium hydride following complete uptake of hydrogen by Ti50A. This study was performed by analyzing and examining partially hydrogenated samples

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Titanium is one of the most used biomateriais in manufacturing dental implants, especially titanium grade 4. However, titanium is a bioinert material, i.e. the interface between titaiiiun-i and host bone is a simple interlocking bonding, which can iead to the loosening ofthe implant and the eventual failure of the implantation. Bone neoformation and long terrn stability can be achieved by using bioactive materiais. Tricalcium phosphate (TCP) is one of the best options among bioactive materiais, due to its chernical and crystallographic structure being similar to that of bone mineral. However, one ofits primary restrictions on clinical use as a ioad-bearing implant is its poor mechanical properties. A good combination of the bioactivity of TCP and the mechanical properties of titanium is considered to be a promising approach to fabricating more suitable biornedical materiais for load-bearing àpplications. Therefore, the aim of this study was to ~eve1op bioactive composites by powder metallurgy using titanium hydride and tricalciuin phosphate to enhance the biocompatibility and the osseointegratjon of dental irnplants. Titanium based composites were prepared from titanium hydride (TiH2) with 2.5, 5, 7.5 and 10% in volume of β-TCP. The TiH2 was provided by Centro Técnico Aeroespacial (CTA) with a mean particle sige of l5μm. The β-TCP was provided by Cerarnic Group from UDESC with particle size below 180 nm. The mixtures were prepared with alcohol and zirconia baus in a high energy mili for five hours, foilowed by drying in a rotating evaporator. The mixtures were then pressed at 15OMPa and sintered at 1200°C for 2 hours in either vacuum or argon atinosphere. The materiais were characterized by scanning eiectron microscopy, transmission electron microscopy, X-ray diffraction and thermal analysis. The decomposition of β-TCP occuned at approximately 1100°C leading to the formation of Ti, CaTiO3, TiO2 and TixPy phases for the composites sintered in argon. For the composites sintered in vacuum it was found the sarne phases, except rutile. The composites sintered in vacuurn were better sintered exhibiting higher densificatjon than those sintered in argon. A main crystal phase of calcium titanate with a needie-like morphology was observed in the porosity of the composites. This phase was found in higher amount in the composite sintered in argon because this material presented higher porosity. This morphology is related to the presence of pores, which allow the growth of calcium titanate on a free surface.
O titânio é um dos biomateriais mais utilizados na confecção de implantes dentários. Dentre os tipos de titânio comercialmente puro (Ti cp), o mais utilizado em implantologia é o da classe quatro. Porém, o titânio é um material bioinerte, ou seja, a fixação óssea sobre a sua superficie acontece por aderência biomecânica. Em materiais bioativos, a fixação ocorre por ligação físico- química. O TCP-13 é um politipo de fosfato de cálcio que desperta muito interesse na utilização em medicina e odontologia por causa da neoformação óssea, porém, as suas propriedades mecânicas são muito baixas, inviabilizando a sua utilização na forma pura. Muitos trabalhos têm sido relatados em que a junção do titânio e fosfatos tem contribuído no desenvolvimento de biomateriais compósitos com características bioativas. O presente trabalho teve por objetivo desenvolver compósitos bioativos ~por metalurgia do pó, utilizando hidreto de titânio / fosfato tricálcico, para melhorar a biocompatibilidade e a osseointegração de implantes dentários. Foram elaborados os compósitos a base de hidreto de titânio (TiH2) com 2,5; 5; 7,5 e 10% em volume de TCP-β. O TiH2 foi doado pelo Centro Tecnológico Aeroespacial (CTA), e apresentava granulometria média de 15 μm. O TCP-β foi fornecido pelo grupo de biomateriais cerâmicos da UDESC com tamanho de partícula inferior a 180 nm. As misturas foram elaboradas com álcool e esferas dé zircônia em moinho atritor de alta energia durante cinco horas, seguidas de secagem em evaporador rotativo. Em seguida as misturas foram compactadas uniaxialmente a frio em matriz cilíndrica e retangular sob pressão de 150 MPa. Os compactados foram sinterizados em atmosfera de argônio e a vácuo nas condições de 1200 °C, durante duas horas. Os materiais foram caracterizados por microscopia eletrônica de varredura, microscopia eletrônica de transmissão, difração de raios-X, e análise térmica pelos métodos de calorimetria diferencial e dilatometria. A decomposição do TCP-β ocorreu a aproximadamente 1100 °C resultando na formação de titanato de cálcio e fosfetos de titânio. As fases resultantes da sinterização em atmosfera de argônio foram Ti, CaTiO3, TiO2 e TixPy. As fases identificadas nos compósitos sinterizados a vácuo foram as mesmas com exceção do rutilo. O compósito sinterizado a vácuo apresentou urna densificação melhor que o sinterizado em argônio. A porosidade e o aparecimento de titanato de cálcio na forma de agulhas foram maiores nos compósitos sinterizados em atmosfera de argônio por causa da maior porosidade.

This Thesis describes the synthesis and characterisation of titanium hydrazido(2-) complexes and their reactivity towards unsaturated molecules. Exploration of the bonding in titanium hydrazido(2-) complexes is performed through structural and computational studies. Chapter 1 introduces current Group 4 hydrazido chemistry and describes its relevance with comparison to Group 4 imido and mid/late metal hydrazido examples. Chapter 2 describes the synthesis and characterisation of new titanium hydrazido(2-) half-sandwich complexes. A general route to new titanium hydrazido(2-) chemistry is described and suppression of dimerisation pathways common to Group 4 alkyl hydrazido(2-) chemistry is investigated. Chapter 3 describes the synthesis, bonding and preliminary reaction chemistry of a new titanium hydrazido(2-) sandwich complex. Through structural and computational techniques, the bonding in the sandwich complex Cp₂Ti(NNPh₂)(py) (14) is explored and the implications to the reactivity of this complex considered. Chapter 4 describes the synthesis of new titanium hydrazido(2-) synthons which is extended to the synthesis of new titanium hydrazido(2-) complexes with diamide-amine type ligands. The bonding of the hydrazido(2-) ligand is explored through structural and computational study of these complexes. Chapter 5 describes the novel reaction chemistry of a diamide-pyridyl titanium hydrazido(2-) complex Ti(N₂N^py)(NNPh₂)(py) (23). Novel reactivity of both the Ti=N_α and N_α-N_β bonds is presented with the mechanisms of some of these transformations probed by density functional theory (DFT) calculations. Chapter 6 presents full experimental procedures and characterising data for the new complexes reported. CD Appendix contains .cif files for all new crystallographically characterised complexes described.

>Magister Scientiae - MSc
Hydrogen has been regarded as an ideal energy carrier for future, it can be stored as a liquid in cryogenic tanks, a gas in high pressure cylinders and as solid in metal hydrides. Hydrogen storage in metal hydrides is of research interest because hydrides often have high energy density than gas or liquid hydrogen and are relatively safe. Ti and Ti alloys are promising hydrogen storage material because they have high affinity for hydrogen, light in weight and react reversibly with hydrogen. This work aims to investigate the hydrogen storage capacity of CP- Ti and Ti6Al4V alloy and Pd/Ti6Al4V alloy, where Pd was deposited on Ti6Al4V alloy. Samples were hydrogenated from room temperature to 650 °C at atmospheric pressure in the vacuum furnace under the 15%H/Ar atmosphere. Hydrogenation was carried out for a period of 3 hours for all samples. Sample composition and layer thickness were determined using Rutherford backscattering spectrometry. The microstructure and phase transformation were investigated using optical microscopy and X-ray diffraction technique. Hydrogen storage capacity was determined using elastic recoil detection analysis and gravimetric method. It was found that hydrogenation temperature has an effect on hydrogen absorption, microstructure and phase transformation. Maximum hydrogen concentration was obtained at hydrogenation temperatures of 550 °C for all materials with 45.57 at.% in CP-Ti, 34.77 at.% in Ti6Al4V alloy and 39 at.% H in Pd/Ti6Al4V coated system. In CP-Ti it was found that hydrogen absorption begins at 550 °C and decreases at hydrogenation temperature of 650 °C and that hydrogenation at both temperatures leads to formation of titanium hydrides and needlelike microstructure. At temperatures below 550 °C no hydrides were formed. For Ti6Al4V alloy ERDA results showed that no significant hydrogen absorption occurred at temperatures below 550 °C and at hydrogenation temperature of 650 °C, hydrogen absorption decreased drastically. The δ- titanium hydride was detected in the sample hydrogenated at 550 °C. Fine needle like microstructure was observed in the sample hydrogenated at 550 °C, and at higher temperature (650 °C ) coarse needles were formed. Pd coatings on Ti6Al4V alloy was found to increase the absorption of hydrogen, and allowing hydrogen to be absorbed at low temperatures.
National Research Foundation (NRF)

This Thesis reports the synthesis and reactions of new hydrazide, alkoxyimide and benzimidamide complexes (L)Ti=NX (X = NAr2, NOtBu or C(Ar)NO^tBu; L = dianionic supporting ligand or ligand set). The work is supported by DFT calculations which are used to rationalise the reaction outcomes observed and, in one case, the bonding in alkoxyimide complexes. Chapter One provides a background to hydrazide complexes, starting with their relevance to nitrogen fixation. In addition, Group 4 imide, alkylidene hydrazide and alkoxyimide complexes are also reviewed. The Chapter focuses in particular on the synthesis, structure, and stoichiometric and catalytic reactions of these complexes with unsaturated substrates. Chapter Two describes the development of the virtually unexplored 1,2-diamination reaction. The substrate scope and isolation of the vinylamine products are discussed. The protonation of the vinylimide complex Ti(N2N^Me){NC(Ph)C(Me)NPh2}(py) and the overall diamination reaction itself is then explored through an in-depth experimental and computational study. Chapter Three details the synthesis of cyclopentadienyl-amidinate supported alkoxyimide complexes. The first detailed reactivity study, supported by structural and computational studies, of any alkoxyimide complex is reported. Novel reactivity at Ti=Nα and, in one instance, Nα–Oβ reductive bond cleavage is observed. Chapter Four describes the reactivity of the benzimidamide complex Cp*Ti{PhC(NⁱPr)2}{NC(Ar^F5)NO^tBu} with a range of substrates including heterocumulenes, aldehydes, isonitriles and B(Ar^F5)3. Novel reactivity at Ti=Nα, and 3-component coupling is presented, and the experimental results supported by structural and computational studies. Chapter Five presents full experimental procedures and characterising data for the new complexes reported.

AbstractLes polluants émergents que sont les résidus de produits pharmaceutiques sont devenus une problématique majeure de par leur persistance et leur accumulation continue dans les différents compartiments de l’environnement. Leur élimination est un des challenges majeurs de ce siècle. Les procédés électrochimiques d’oxydation avancée (PEOA) tel que l’oxydation anodique (AO) et l’électro-Fenton (EF) ont démontré leur efficacité pour la dégradation et la minéralisation complète de cette classe de polluant. Un oxyde de titane sous-stœchiométrique déposé par plasma sur un alliage de titane a été étudié comme anode alternative peu coûteuse, stable et efficace au cours des procédés d’OA et d’EF pour la dégradation et la minéralisation de deux pharmaceutiques, l’amoxicilline (AMX) et le propanolol (PPN). Une excellente minéralisation de ces deux composés a été atteinte avec l’anode Ti4O7 comparé à l’utilisation d’une anode dimensionnellement stable (ADS) et d’une anode de platine (Pt) avec des conditions expérimentales similaires, mais une plus faible efficacité a été observé par comparaison à une anode de diamant dopé au bore (DDB) au cours du procédé d’OA. Une quasi-total minéralisation (96%) du PPN a été atteinte avec l’anode Ti4O7 au cours du procédé EF après 8 h d’électrolyse à 120 mA. Plusieurs intermédiaires aromatiques, bicycliques et autres ont été identifiés et quantifiés au cours du traitement électrochimique des deux composés pharmaceutiques, ainsi que des acides carboxyliques à chaîne courte et des ions inorganique comme produits finaux de dégradation. Des voies plausibles de dégradation ont été proposées à partir des intermédiaires identifiés, des ions inorganiques libérés ainsi que des données obtenues sur les acides carboxyliques et le COT. La solution initiale d’AMX a mené à une relativement forte inhibition de la bactérie V. fisheri, qui a ensuite augmenté au cours des premiers stades de l’électro-oxydation de par la formation d’intermédiaires cycliques plus toxiques que la molécule mère, avant de diminuer nettement au cours des étapes suivantes de l’électrolyse. Puisque le Ti4O7 est produit principalement à partir du TiO2, un matériau bon marché et abondant, ce matériau d’anode pourrait être une alternative intéressante pour le traitement des eaux usées industrielles par oxydation électrochimique. Par ailleurs, une cathode de feutre de carbone modifiée par des composés hydroxydes à double couche CoFe (CoFe-LDH/CF) et synthétisée par un procédé solvothermique a été étudiée come catalyseur/électrode pour la dégradation du polluant organique Acide Orange II (AO7) par le procédé EF sur une gamme large de pH. Une excellente minéralisation de ce colorant a été atteinte pour des pH allant de 2 à 7.1, avec une élimination du COT largement supérieure à celle atteinte en utilisant le procédé EF avec une cathode de feutre de carbone brut, quel que soit le pH étudié. La cathode préparée a montré une bonne capacité de réutilisation et peut constituer une alternative pour le traitement des eaux usées à des valeurs de pH naturel
Pharmaceuticals residues as emerging pollutants have become a major concern due to their persistence and continuous accumulation in various environmental compartments and their removal is one the major challenges of this century. Electrochemical advanced oxidation processes (EAOPs) such as anodic oxidation (AO) and electro-Fenton (EF) have shown to be efficient techniques for complete degradation and mineralization of this class of pollutants. A substoichiometric titanium oxide (Ti4O7) deposited on titanium alloy by plasma elaboration was investigated as an alternative stable and efficient low cost anode materials for application in AO and EF for degradation of pharmaceuticals amoxicillin (AMX) and propranolol (PPN) and mineralization of their aqueous solutions. Excellent mineralization of both pharmaceuticals was achieved with Ti4O7 anode compared to dimensional stable anode (DSA) and platinum (Pt) anodes at similar experimental conditions, but less efficient when compared with boron doped diamond (BDD) anode during AO treatment. Almost complete mineralization (96%) was attained with Ti4O7 anode in EF degradation of PPN at 120 mA after 8 h of electrolysis. Several aromatic, bicyclic and other intermediate byproducts were identified and quantified during the electrochemical treatment of both pharmaceuticals, with the final end products in the treated solutions being short-chain carboxylic acids and inorganic ions. Plausible mineralization pathways for both pharmaceuticals were proposed based on the identified intermediates, released inorganic ions and carboxylic acids as well as TOC data. Initial AMX solution shows relatively high inhibition to V. fischeri bacteria, which further increased at the early stage of electrooxidation due to formation of cyclic intermediates more toxic than mother molecules but sharply decreased at the later stage of electrolysis. Since the Ti4O7 is produced mainly from TiO2 which is very cheap and highly abundant material, this anode material could be an interesting alternative electrode in industrial wastewater treatment by electrochemical oxidation. On the other hand, CoFe-layer double hydroxide modified carbon-felt (CoFe-LDH/CF) cathode synthesized by solvothermal process was studied as a heterogeneous catalyst/electrode for degradation of organic pollutant Acid Orange II (AO7) over a wide pH range. Excellent mineralization of this azo dye solution was achieved in pH range 2 – 7.1, with TOC removal much higher than corresponding homogeneous EF with raw carbon-felt (CF) at all pH studied. The prepared cathode exhibited good reusability and can constitute an alternative for the treatment wastewater effluents at neutral pH values

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Neste trabalho investigou-se a obtenção do composto TiFe a partir da moagem de alta energia de misturas de pós de TiH2 e Fe, seguida de aquecimento sob vácuo para a reação de síntese. No lugar do Ti, o TiH2 foi escolhido como precursor em razão de sua fragilidade, benéfica para a diminuição da aderência dos pós ao ferramental de moagem. Foram preparados dois lotes de misturas obedecendo-se a relação Ti:Fe de 50:50 e 56:44. Ambos foram processados em um moinho do tipo planetário por tempos que variaram de 5 até 40 horas, sob atmosfera de argônio de elevada pureza. Em todos os experimentos foram mantidos constantes a velocidade de rotação do prato do moinho, a quantidade de amostra, o diâmetro e o número de bolas. As amostras moídas foram caracterizadas por calorimetria exploratória diferencial (DSC), termogravimetria (TG), microscopia eletrônica de varredura (MEV), difração de raios X (DRX) e fluorescência de raios X por dispersão de energia (EDXRF). Apenas TiH2 e Fe foram observados nas amostras moídas, com um grau crescente de mistura em função do tempo de moagem. O composto TiFe nanoestruturado (12,5 a 21,4nm) foi obtido de forma majoritária em todas as amostras após a reação de síntese promovida pelo tratamento térmico a 600ºC (873K). As amostras reagidas foram caracterizadas por microscopia eletrônica de transmissão (MET) e DRX. Um equipamento do tipo Sievert, operando sob um fluxo constante (modo dinâmico), foi utilizado para levantar as curvas termodinâmicas de absorção e dessorção de hidrogênio. Todas as amostras absorveram hidrogênio à temperatura ambiente (~298K) sem a necessidade de ciclos térmicos de ativação. Os melhores resultados foram obtidos com as amostras moídas por 25 e 40 horas, de composição não estequiométrica 56:44. Tais amostras absorveram e dessorveram hidrogênio à temperatura ambiente, sob os platôs de aproximadamente 6,4 e 2,2bar (~0,6 e 0,2MPa), respectivamente. A capacidade máxima de armazenamento foi de 1,06% em massa de hidrogênio (H:M~0,546), sob pressão de até 11bar (1,1MPa), com reversão de até 1,085% em massa de hidrogênio (H:M~0,559), sob pressão de até 1bar (0,1MPa). Estas amostras também apresentaram maior cinética de absorção e dessorção de hidrogênio com fluxos de 1,23 (25h) e 2,86cm3/g.min. (40h). Tais resultados são atribuídos à variação composicional da fase TiFe e à maior quantidade de TiH2 livre.
Tese (Doutorado em Tecnologia Nuclear )
IPEN/D
Instituto de Pesquisas Energéticas e Nucleares - IPEN-CNEN/SP

Arsenic (As) contamination is a worldwide problem, and millions of people are suffering from it. There are two major inorganic forms of As in waters: arsenate(V) and arsenite(III), and adsorption to a sorbent material may be an efficient method to handle them. In this study, we focused on As(III), the more toxic form, which predominates under reducing conditions. The As(III) removal properties of four sorbent materials: hydrotalcite, Mg−Al layered double hydroxide, amorphous aluminium hydroxide and amorphous titanium oxide, are examined from the following viewpoints: As(III) adsorption, the effects of pH, the effects of adsorbent concentration, adsorption as a function of dissolved As(III), and the effect of co-existing anions (HCO3− and PO43−). The maximum adsorption of As(III) to HT (0.1 mmol As(III)/g adsorbent), Mg-Al LDH (0.1 mmol As(III)/g adsorbent), am-Al(OH)3 (0.22 mmol As(III)/g adsorbent), and am-TiO2 (0.21 mmol As(III)/g adsorbent) occurred at pH 7.5, 7, 7, 8, respectively. At this pH, approximately 20%, 62%, 35%, and 98.3%, respectively, of the added As(III) was adsorbed. When the As(III) to sorbent ratio was increased, the adsorption was instead around 7% to am-Al(OH)3 (2.2 mmol As(III)/g adsorbent), and 46.3% to am-TiO2 (2.1 mmol As(III)/g adsorbent). These figures show that am-TiO2is the most efficient sorbent for As(III) adsorption of the four materials tested, Mg-Al LDH is second best, while HT and am-Al(OH)3 are not suitable for As(III) removal. The adsorption of As(III) to Mg-Al LDH as a function of dissolved As(III) could be adequately described by a linear equation, suggesting that As(III) adsorption to Mg-Al LDH was governed by anion exchange. As a result, the co-existing anions (HCO3- and PO43-) showed a significant influence on As(III) adsorption to Mg-Al LDH. Considering the interfering effects of co-existing anions on am-TiO2, HCO3− did not influence As(III) adsorption, while PO43- caused a slight but clear competition effect. Overall, am-TiO2 would be the best choice of these four materials in contact with As-contaminated groundwater due to its superior As(III) removal properties and the limited competition from co-existing anions on As(III) adsorption.
Alltför höga halter av arsenik (As) i vatten är ett världsomspännande problem som orsakar hälsoproblem för miljontals människor. Det finns två huvudsakliga oorganiska former av As i vatten: arsenat(V) och arsenit(III), och adsorption till ett material (s.k. ”sorbent”) kan vara eneffektiv metod för att avlägsna dem från vatten. I denna studie fokuserade vi på arsenit(III), den mer giftiga formen, vilken dominerar under reducerande förhållanden. Vi undersökte adsorptionsegenskaperna för arsenit(III) för fyra sorbentmaterial som kan vara tänkbara när det gäller arsenikrening av förorenade vatten: hydrotalkit, s.k. Mg-Al LDH (Mg-Al-skiktad dubbelhydroxid), am-Al(OH)3 (amorf aluminiumhydroxid), och am-TiO2 (amorf titandioxid). Dessa material undersöktes när det gäller följande: adsorption av arsenit(III) som funktion av pH,betydelsen av sorbentkoncentration, adsorption som funktion av löst arsenit(III) (”isoterm”), och konkurrens från samexisterande anjoner (HCO3− och PO43−). Den maximala adsorptionen av As (III) till HT (0,1 mmol As(III)/g sorbent), Mg-Al LDH (0,1 mmol As(III)/g sorbent), am-Al(OH)3 (0,22 mmol As(III)/g sorbent) och am-TiO2(0,21 mmol As(III)/g sorbent) inträffade vid pH 7,5, 7, 7, respektive 8. Vid dessa pH-värden adsorberades ungefär 20%, 62%, 35% respektive 98,3% tillsatt As(III). När kvoten mellan As(III) till sorbent ökades blev adsorptionen istället cirka 7% till am-Al(OH)3 (2,2 mmol As(III)/g sorbent) och 46,3% till am-Ti02(2,1mmol As(III)/g sorbent). Dock var adsorptionsmängden per viktsenhetsorbenthögre över hela pH-området. Dessa siffror visar att am-TiO2 är det mest effektiva av de fyra testade materialen för As(III)-adsorption, Mg-Al LDH det näst bästa, medan HT och am-Al(OH)3 är olämpliga för detta ändamål. Adsorptionen av As(III) till Mg-Al LDH som funktion av löst As(III) kunde beskrivas väl med en linjär ekvation, vilket antyder att adsorptionen av As(III) till Mg-Al LDH styrdes av anjonbyte. I konsekvens med detta hade de samexisterande anjonerna (HCO3- och PO43-) ett betydande inflytande på As(III)-adsorptionen till Mg-Al LDH. För am-TiO2 påverkade HCO3− inte As(III)-adsorptionen, medan PO43- orsakade en liten men tydlig konkurrenseffekt. Sammantaget är am-TiO2 det bästa valet av dessa fyra material i kontakt med As- kontaminerat grundvatten på grund av dess betydligt bättre förmåga att avskilja arsenit(III) och den förhållandevis blygsamma konkurrensen från andra anjoner.

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Mechanical alloying is a powder processing technique involving cold welding, fracturing mechanisms and rewelding of powder particles in a ball mill. The present work applied this technique with the purpose of processing titanium, niobium and tin alloys, through planetary ball mill and attritor mill. The atomic percentages of these elements were varied in six differents ways. The niobium hydrate was used on production of some alloys in study, with the purpose to observe the effects during the milling and on the alloys obtained after sintering. Differences between processing in planetary ball mill and attritor mill, as well the cold welding influences on the kinetic parameters of milling process were approached. The use of niobium hydrate result in a decrease of powders average crystallite size, and an increase of micro hardness of sintered alloys. This work obtained beta titanium alloys and alpha-beta titanium alloys in namometric sizes. The average crystallite size, for milled powders, was 7,6 nm.
Mecano-síntese é uma técnica de processamento em pó que envolve a soldagem a frio, mecanismos de fratura e a resoldagem das partículas de pós, em moinhos de bolas. O presente trabalho utilizou esta técnica com o propósito de processar ligas de titânio, nióbio e estanho, através de moinhos de bolas planetário e de atrito. As porcentagens atômicas destes elementos foram variadas de seis maneiras diferentes. O hidreto de nióbio foi utilizado na produção de algumas ligas em estudo, com o propósito de se observar os efeitos durante a moagem e na liga obtida após a sinterização. Diferenças entre o processamento em moinho de bolas planetário e o moinho de atrito, assim como as influências da soldagem a frio nos parâmetros cinéticos do processo de moagem, foram abordadas. O uso do hidreto de nióbio resultou na diminuição do tamanho médio de cristalito dos pós, e em um acréscimo na microdureza das ligas sinterizadas. Neste trabalho foram obtidas ligas de titânio beta e de titânio alfa-beta, em tamanhos nanométricos. O tamanho médio do cristalito, para os pós moídos, foi de 7,6 nm.

Application de l'electrochimie a haute temperature et sous pression illustree par trois cas de corrosion: 1) corrosion du titane et de ses alliages en milieu sulfurique 2) corrosion d'un acier a 13% de chrome en milieu carbonique; 3) corrosion d'aciers austeno-ferritique en milikeu carbonique contenant de l'hydrogene sulfure. Identification de differents facteurs permettant l'amelioration de la resistance a la corrosion de ces differents materiaux

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In this work, the effect of sodium hydroxide as a glass foaming agent using glass waste in the foam formulation was performed. During the synthesis process, the variation of temperature, heating rate and sintering time was investigated. Sample density and average pore sizes were estimated using mercury porosimetry. The morphology of the glass foams were evaluated using scanning electron microscopy, phase formation was studied using X-ray diffraction, and chemical composition was estimated using X-ray fluorescence. As a result, glass foam with hierarchical density.
Neste trabalho foi realizado um estudo sobre a ação do hidróxido de sódio como agente formador de espuma vítrea usando resíduos de vidro em sua composição. Para a síntese, investigou-se a variação da temperatura, da taxa de aquecimento e do tempo de sinterização. Utilizando-se a técnica de porosimetria de mercúrio, para estimar a densidade e o tamanho médio de poros. A morfologia das espumas vítreas foi avaliada através da microscopia eletrônica de varredura de alta resolução (FEG) e as fases das espumas vítreas foram caracterizadas pelas técnicas de difração de raios X e a composição química estimada usando fluorescência de raios X.

The main focus areas of this master thesis include the writing of a literature review, which contains an overview and segregation of pigments which are used in the preparation of cosmetic products. The thesis is focused on the properties and characterization of pigments for use in cosmetology. The following focus is on legislation, more specifically on pigments that the cosmetic industry allows, limits and does not allow. The main part of this thesis is an overview of methods for the characterization of pigments. The practical part deals with the characterization of particles of selected cosmetic pigments by applying methods for determination of color, elemental and phase composition, particle size and morphology. The thesis is concluded by evaluation of the achieved results.

Les objectifs de cette étude sont de comprendre les mécanismes de pénétration de l’hydrogène dans le titane sous polarisation cathodique en milieu marin et d’en évaluer les risques afin de donner un certain nombre de recommandations pour l’ingénieur. Les alliages T40 monophasé α et TA6V ELI biphasé α/β ont été choisis afin d’interroger l’influence de chacune des phases (α et β) et de leur distribution sur les phénomènes de fragilisation par l’hydrogène. Pour différents potentiels cathodiques, les cinétiques d’absorption de l’hydrogène dans différents milieux et particulièrement en eau de mer artificielle ont été étudiées. Elles sont très comparables entre les deux types d’alliages bien que les mécanismes mis en jeu et les concentrations en hydrogène atteintes pour chacun soient différents. La localisation des hydrures influencée par la structure métallographique des alliages est questionnée. Celle-ci conditionne les évolutions des propriétés mécaniques étudiées au travers d’essais de traction pour différentes orientations de sollicitation, teneurs en hydrogène et rayons d’entaille. La modélisation par éléments finis de chacun des essais permet d’accéder à des critères locaux d’endommagement et de rupture (contrainte hydrostatique versus déformation plastique équivalente). L’ensemble des travaux nous a permis de proposer des abaques reliant les évolutions des propriétés mécaniques à la concentration en hydrogène. D’autre part, une comparaison des résultats des expériences en laboratoire avec ceux des essais par couplage galvanique avec des anodes sacrificielles en eau de mer naturelle nous a permis de valider un seuil de potentiel de couplage galvanique maximal utilisable de -1,1 V/ECS en eau de mer, dans le cadre des conditions d’étude
This study aims at understanding the hydrogen absorption mechanisms in titanium under cathodic polarization in seawater and then to provide risk assessments for engineers. The single-phase T40 and the two-phase TA6V ELI alloys were employed to study the influence of α and β phases as well as their distribution on the hydrogen embrittlement mechanisms. Hydrogen absorption kinetics were studied for several cathodic potentials in artificial seawater, while other electrolytes were used to validate some hypothesis. These kinetics are observed to be similar between the two alloys despite the differences in the absorption mechanisms and the hydrogen concentration at saturation. Then, this work investigates the role of the metallographic structure on the localisation of hydrides. The evolutions of the mechanical properties were studied by tensile tests on various orientations of solicitation, hydrogen concentrations and notches. As a result, these properties are observed to depend on the hydrogen concentration and the hydrides location. Models by finite elements were also used to determine local mechanical criterions of internal damage and fracture in term of hydrostatic stress and equivalent plastic strain. It allowed us to establish an abacus linking the evolutions of the mechanical properties to the hydrogen concentration. Moreover, this work also results in the determination of a maximum threshold of the cathodic potential at -1,1 V/SCE by comparing the laboratory results with those of on-site galvanic coupling by sacrificial anodes in natural seawater

碩士
臺北醫學大學
口腔科學研究所
94
Titanium-based alloys with excellent biocompatibility have been investigated by many researches. It is due to its passive oxide film. The surface characteristics of titanium implant, such as pore sizes/roughness, oxide thickness are related to initial cell behaviors and osseointegration. It seems to be helpful to osseointegration if can effectively keep the oxidation in nanoporous and increase oxide thickness. Based on this study, in order to get the thick oxidation and the minimum pore size, the titanium hydride is the main factor in forming thick nanoporous titanium oxide structure. The present electrochemiscal process was performed as surface treatment of titanium-based implant. Titanium hydride (TiH2) was formed on titanium implant surface after cathodic treatment. Nanoporous titanium oxide structure was formed by anodic surface treatment. As the mention above, physical properties, chemical properties as well as biocompatibility of titanium implant with and without electrochemical treatments were analyzed clearly. Furthermore, mechanism of bone healing on nanoporous implant surface and interaction were also discussed clearly.

Titanium is well known for its excellent properties, such as high strength-to-weight ratio and outstanding corrosion resistance. However the high cost of this metal has confined its applications to those mostly within the aerospace and military industries. The high purchase price of titanium is primarily driven by the need for intricate metal extraction processes, as well as the sensitivity towards conventional metal working operations. Among the potential solutions, powder metallurgy (P/M) technology provides an economical approach to bring down the price of finished titanium products. However, there are still many problems, such as the residual porosity in the sintered body, that need to be overcome. In this thesis, a fundamental study was carried out focusing on the P/M press-and-sinter technique, using commercially pure titanium (CP Ti) as well as two binary titanium alloys, namely Ti-Ni and Ti-Sn. The influence of several processing parameters including compaction pressure, lubricant type/concentration, sintering time/temperature were performed on both the CP and binary systems. The principal tools utilized for mechanical characterization were hardness and tensile testing, whereas optical microscopy, x-ray diffraction (XRD), and scanning electron microscopy were employed to identify the microstructural features present. Press-and-sinter P/M strategies were successfully developed for all of the blends studied. For CP-Ti, a maximum tensile strength >750MPa and near full theoretical density (~99%) were achieved. Transitions in the size and the size distribution of pores and ?-Ti grains were also observed and quantified. It was found these transitions, as well as the powder impurities present (i.e. oxygen and carbon), greatly influenced the final mechanical properties. In the case of the binary alloys, it was shown that liquid phase sintering (LPS) significantly improved the sintered density for the Ti-10%Ni composition, when sintered at l100°C. A eutectic microstructure (CP-Ti + Ti2Ni), coupled with grains of CP-Ti, were identified as the principal phases present. On the other hand, the Ti-Sn alloys only showed a modest increase in sintered density compared to the CP-Ti, owing to the high solubility of Sn in Ti. In terms of crystal structure, XRD highlighted that the Sn containing samples were fully CP-Ti.

碩士
國立成功大學
機械工程學系
104
Nowadays, the great majority believe that there is great potentiality in hydrogen storage alloy storing hydrogen by physical and chemical absorption. MgH2 has high capacity and unexpansive. However, its operation temperature is high and owns poor kinetics. Currently, scientists find that adding transition elements can improve the properties of hydrogen storage alloy. In this research, outstanding improvements of kinetic and thermal properties are given by addition of Palladium and Titanium hydride to Magnesium-based alloy. The research involves experiment and quantum-mechanical calculation. In experiment, magnesium-based alloy is used as main material, into which TiH2/Pd are added separately. TGA/DSC and PCT measure the capacity, spending time and temperature of abs/des-orption, additionally, SEM and XRD analyze the structures and components of material. The quantum mechanical calculation is based on Density Function Theory and the First Principle. The changes of DOS and stability are observed after doping. The results of the real experiment clearly demonstrate following points. (1) Because Pd owns highly affinity to hydrogen and Mg6Pd was found from the XRD, it is clearly shown that Pd is beneficial of dehydrogenation. 2MgH2-0.1Pd has the highest capacity of all the alloys listed, approximately 5.5 wt.%. (2) From XRD analysis, it could not find any new Ti-related compound. Thus, TiH2, considered as the catalyst, leads to the condition of 2MgH2-TiH2 and 2MgH2-TiH2-0.1Pd efficiently absorbing hydrogen in low temperature. (3) Due to the synergistic effects between Pd and TiH2 (PdTi2 and Pd2Ti are produced by mechanical alloying), 2MgH2-TiH2-0.1Pd owns the lowest dehydrogenation temperature. (4) The higher temperature is; the stronger kinetic energy molecule has. Generally, the time spending on absorption would decrease as the temperature raise. However, too high temperature is unbeneficial to reaction since the absorption reaction is exothermic. (5) Activation plays an important role in the abs/des-orption. It shortens the abs/des-orption time because of the surface area increasing. From SEM, it is clear that the size and surface become smaller and rougher. (6) Even though PdTi2 and Pd3Ti decrease the limited dehydrogenation temperature, they need more pressure to react. Therefore, the plateau of 2MgH2-TiH2-0.1Pd is slightly higher than others. (7) According to the PCT curves of 2MgH2-TiH2-0.1Pd at the different temperature, Van’t Hoff related plot can be described. 2MgH2-TiH2-0.1Pd’s enthalpy (83 KJ‧mol-1) and entropy (135.8 J‧mol-1 ) are given by Van’t Hoff related plot. Furthermore, in simulation part, there are also some points: (1) adding Pd/Ti would increase distance of Mg-H. (2) From MgH2’s T/PDOSs, there is an gap between the valence band and conduction band, roughly 4.0eV. (3) From MgH2-Pd’s T/PDOSs, there is a spd hybridization between Pd, Mg and H atom at +0.2eV. It moved the bottom of the conduction band below Fermi energy. (4) Because the peak of MgH2-Ti’s PDOSs’ do not alter much but slightly move, Ti is believed as the catalyst. (5) Energy Gap is vanished by the electrons provided by Ti-d. It means the temperature and energy of dehydrogenation decreasing. (6) The dehydrogenation energy decreases while doping catalytic elements and temperature falls simultaneously.

Aluminium foams have high specific strength and higher stiffness than other contemporary packaging materials. They have important application as packaging material for critical applications that needs highest safety standards. Commercially, established processes for manufacturing of metal foam include Hydro/Alcan Process, Alporas Process, Gasar/Lotus process, Alulight/Foaminal process, Formgrip Process, ALUHAB and Powder Metallurgy route. In the above methods, control of the shape and size of pores is difficult. In these techniques significant changes in the chemistry of the melt is carried out to foam the metals. The Gap area of the above commercial processes is minimised by “Hollow sphere technique”. This process overcomes the limitations in achieving the cell wall thickness, shape of the pores, non-uniformity of pore size and its distribution in comparison to existing commercial established process. Moreover, it is easy to fabricate foams, with desired/tunable mechanical properties. This thesis discusses, the fabrication technique of hollow spheres using a special die by successive pressing of hollow tube through a series of ten die cavities. The fabricated hollow spheres are cured in the required shape using suitable bonding material (resin based or metal binder). The advantage of this process being, any asymmetrical shape is easier to fabricate and mechanical properties can be controlled by using spheres with different diameters and varying wall thickness. This process does not require any additional alloy nor does it require huge experimental facilities for fabrication. This mechanical processing method of hollow sphere technique can fabricate different diameter spheres with varying wall thickness. By arranging spheres in desired pattern, “graded foams” which is a new concept exhibiting peculiar properties is introduced. This work includes assessment of mechanical properties and its comparison with respect to commercially available foams. The main properties under consideration were yield strength, Young’s modulus, plateau stress, densification strain and energy absorption evaluation. This thesis also, discusses practical application of developed product in the field of engineering as base isolators, which is novel. The thesis concludes by highlighting advantages of this technique over the other existing commercially established fabrication routes: • Desired/tunable Mechanical properties can be achieved on case-to-case basis with ease and can be supported by impact simulations using finite element analysis. • It is the fastest and easiest way for production of High purity aluminium foam and in achieving any asymmetrical shapes. • Relative Densities of the order of 10%, 20%, 30%, 40%, 50 % and higher can be achieved by varying only the hollow sphere diameter or wall thickness of the sphere. • Cost effective and Environment/Eco-friendly and Recyclable This route of hollow spheres fabrication and the final product is different from the prevalent commercially established routes of metal foam fabrication using hollow sphere technique.

Obecnie coraz popularniejsze w leczeniu człowieka staje się podejście zwane medycyną spersonalizowaną. Jej główne założenie polega na tym, że sposób leczenia dobiera się do konkretnego pacjenta, a nie danej choroby. Natomiast w przypadku implantologii związane jest to z projektowaniem wszczepów o określonym kształcie i właściwościach. Zgodnie z tą zasadą poszukuje się nowych, wielofunkcyjnych materiałów implantologicznych, które można byłoby dostosować do potrzeb różnych osób. W kontekście badań nad implantami kostnymi ważną rolę odgrywa zarówno topografia, jak i chemia powierzchni, które mogą być odpowiedzialne za efektywną osteointegrację, a także oddziaływanie z cząsteczkami leków. Najczęściej wszczepy są wykonane z tytanu lub jego stopów, ale mimo swoich licznych zalet nie zapewniają szybkiej adhezji komórek, co może prowadzić do odrzutu implantu. Dlatego też jednym ze sposobów modyfikacji biomateriałów jest pokrycie ich nanoporowatą warstwą tlenku tytanu(IV) (TiO2) otrzymaną w procesie anodyzacji. Dodatkowo w celu dalszej poprawy biokompatybilności ich powierzchnia może zostać sfunkcjonalizowana. Z tego powodu głównym celem badań było zmodyfikowanie nanoporowatych warstw tlenku tytanu(IV) o różnej strukturze krystalicznej: (i) wodorotlenkiem sodu (NaOH) oraz (ii) pochodnymi silanu różniącymi się grupami funkcyjnymi ((3-aminopropylo)trietoksy-silanem (APTES), (3-glicydyloksypropylo)trimetoksysilanem (GPTMS) i (3-merkapto-propylo)trimetoksysilanem (MPTMS)). Zbadano również wpływ modyfikacji na proces uwalniania leków oraz na interakcję z komórkami osteoblastopodobnymi, a także określono bioaktywność takich podłoży. Dodatkowo anodowe warstwy tlenku tytanu(IV) zostały pokryte kompozytem hydroksyapatytu i chitozanu w procesie osadzania elektroforetycznego. Funkcjonalizacja powierzchni prób TiO2 wymienionymi związkami została potwierdzona różnymi technikami, które pozwoliły na kompleksową charakterystykę oraz określenie ich najważniejszych właściwości. Na podstawie uzyskanych wyników można stwierdzić, że zarówno struktura krystaliczna tlenku tytanu(IV), stężenia użytych roztworów, jak i czas prowadzenia procesu wpływały na efektywność modyfikacji. Co więcej, funkcjonalizacja podłoży oraz obróbka termiczna powodowały wzrost hydrofilowości próbek. Wprowadzone modyfikacje miały na celu między innymi spowolnienie uwalniania modelowych leków (ibuprofenu i gentamycyny). Na podstawie parametrów modelu desorpcji-desorpcji-dyfuzji (DDD) stwierdzono, iż zmiana struktury krystalicznej oraz chemii powierzchni powodowała spowolnienie procesu uwalniania ibuprofenu, natomiast nie wpływała na profil dostarczania gentamycyny. Nowym badanym rozwiązaniem było jednoczesne wprowadzenie leków do nośnika oraz analiza kinetyki ich wspólnego dostarczania. Uzyskane wyniki dowiodły, że morfologia oraz faza krystaliczna TiO2, a także procedura impregnacji wpływały na opóźnienie uwalniania tylko gentamycyny. Z kolei badania komórkowe na testowanych podłożach pokazały, iż komórki obu linii (SAOS-2 i MG-63) wykazywały lepszą przeżywalność, adhezję i proliferację na modyfikowanych warstwach tlenku tytanu(IV). Co więcej, próbki o strukturze anatazu lub anatazu/rutylu charakteryzowały się lepszą bioaktywnością. Podsumowując, można stwierdzić, że zaproponowane funkcjonalizacje anodowego TiO2 pozwoliły na poprawę odpowiedzi komórkowej oraz wpłynęły na zmianę kinetyki uwalniania leków.
Nowadays, personalized medicine is becoming more and more popular. This approach assumes that the method of treatment is selected rather for a particular patient than for a given disease. In the case of implantology, it is associated with a custom-designed implants having a specific shape and properties. According to this principle, new multifunctional implantable materials, that could be adapted to the needs of different people, are sought. In case of bone implants, both topography and surface chemistry play an important role, and may be also responsible for effective osseointegration and interaction with drug molecules. Most often used implants are made of titanium or its alloys. However, despite many advantages, they do not provide rapid cell adhesion, which can lead to the recoil of the implant. Therefore, one of the proposed modifications of such biomaterials is to form nanoporous titanium dioxide (TiO2) layers on metal surfaces by using anodization process. Additionally, in order to further improve biocompatibility, their surface can be functionalized with different molecules. For this reason, the main aim of this research was to modify nanoporous titanium dioxide layers having different crystalline structure with: (i) sodium hydroxide (NaOH) and (ii) silane derivatives with different functional groups (i.e., (3-aminopropyl)triethoxysilane (APTES), (3-glycidyloxypropyl)trimethoxysilane (GPTMS) and (3-mercapto-propyl)trimethoxysilane (MPTMS)). Their impact on the drug release process and the interaction between the osteoblast-like cells and the biomaterial was investigated. Moreover, the bioactivity of the samples was also determined. In addition, anodic samples were coated with the hydroxyapatite and chitosan composite by using the electrophoretic deposition technique. Functionalization of the TiO2 surfaces was confirmed using various techniques that allowed for their comprehensive characterization and determination of the most important properties. The results showed that the crystalline structure of titanium dioxide, the concentration of solutions, and the process duration influenced effectiveness of the modifications. What is more, both the substrate functionalization and thermal treatment increased the hydrophilicity of the samples. The above modifications aimed at slowing down the release of model drugs (i.e., ibuprofen and gentamicin). Based on the desorption-desorption-diffusion model (DDD) parameters, it was found that the change in the crystal structure and surface chemistry slowed down the release kinetics of ibuprofen, but did not affect the delivery profile of gentamicin. Moreover, the simultaneous loading of the model drugs into the nanopores, as well as the the study of the kinetics of their delivery was successfully proposed for the first time. The obtained results showed that the morphology and crystalline structure of TiO2, as well as the drug loading procedure, had impact only on the release of gentamicin, causing its delay. Finally, cellular tests showed that cells of both lines (SAOS-2 and MG-63) exhibited better survival, adhesion, and proliferation on modified titanium dioxide layers. Moreover, samples with anatase or anatase/rutile structure were characterized by better bioactivity. To sum up, it can be concluded that the proposed functionalizations of anodic TiO2 led to the improvement in both cellular response and drug release kinetics.

5 Abstract Tobacco mature pollen rehydrates in vivo on a stigma tissue, and develops into the rapidly-growing pollen tube. This rehydration process is accompanied by the de-repression of stored mRNA transcripts, resulting in the synthesis of novel proteins. Furthermore, such metabolic switch is also likely to be regulated on the level of post-translational modifications of the already-present proteins, namely via phosphorylation, since it was shown to play a significant regulatory role in numerous cellular processes. Since only a minor part of proteins is phosphorylated in a cell at a time, the employment of various enrichment techniques is usually of key importance. In this diploma project, metal oxide/hydroxide affinity chromatography (MOAC) with aluminium hydroxide matrix was applied in order to enrich phosphoproteins from the mature pollen and the 30-minute in vitro activated pollen crude protein extracts. The enriched fraction was separated by both 2D-GE and gel-free liquid chromatography (LC) approaches with subsequent mass spectrometric analyses. Collectively, 139 phosphoprotein candidates were identified. Additionally, to broaden the number of phosphorylation sites identified, titanium dioxide phosphopeptide enrichment of trypsin-digested mature pollen crude extract was performed. Thanks to the...