Made available in DSpace on 2014-10-09T12:41:41Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:15Z (GMT). No. of bitstreams: 0 / A instalação de implantes odontológicos requer a presença de substrato ósseo adequado para garantir estabilidade e equilíbrio biomecânico. A deficiência óssea requer procedimentos de enxertia para adequar o volume para a instalação de implantes, porém a utilização de enxertos autógenos causa aumento de morbidade ao paciente e o uso de material homógeno e xenógeno apresenta dúvidas quanto à reação autoimune, transmissão de doenças e ao grau de reabsorção do enxerto. Com o grande desenvolvimento científico e tecnológico dos biomateriais, os materiais cerâmicos, tornaram-se alternativas promissoras para a recomposição da estrutura óssea perdida. As cerâmicas à base de fosfato de cálcio como a hidroxiapatita (HA) e o beta- fosfato tricálcido (beta-TCP), são materiais que apresentam qualidades desejáveis no processo de neoformação óssea como, por exemplo, a biocompatibilidade, bioatividade e osteocondutividade. A proposta deste trabalho é desenvolver e estudar corpos de prova na forma de cúpula oca de hidroxiapatita preenchidos por coágulo, beta- TCP e composto vitamínico, para estudar a osteogênese supracortical, a partir do potencial osteocondutor da cúpula de HA. As cúpulas foram obtidas por prensagem isostática a 200 MPa e sinterização ao ar a 1100°C por 60 minutos. As caracterizações físico-químicas das matérias-primas e da cúpula de HA foram realizadas por difração de raios X, microscopia eletrônica de varredura e determinação da densidade. Na caracterização biológica, foram realizados o teste de citotoxicidade in vitro e ensaio in vivo. Foram designados 9 coelhos (raça Nova Zelândia), sendo instaladas 18 cúpulas, divididas em três grupos, de acordo com o preenchimento: controle, composto vitamínico e β-TCP em forma de pó. O período de reparação tecidual foi de 8 semanas, no qual foram aplicados marcadores de fluorescência. Após o período de cicatrização e eutanásia, as amostras foram incluídas em resina para a obtenção das lâminas e observadas em microscópio de fluorescência, para avaliar a quantidade de tecido ósseo neoformado, em microscópio de campo claro, para verificar as células presentes no tecido formado e por Espectroscopia de Energia Dispersiva, para análise química, da formação no interior das cúpulas. Como resultados, a cúpula de hidroxiapatita apresenta bom desempenho como arcabouço para neoformação óssea acima da cortical da tíbia de coelhos, pois manteve-se íntegra, com boa estabilidade e boa integração ao tecido ósseo, e principalmente pela neoformação óssea, demonstrando seu potencial osteocondutor. Em relação aos materiais de preenchimento, o beta-TCP apresenta maior valor de área de osso neoformado, em comparação com o coágulo. Nas cúpulas com preenchimento de composto vitamínico, não há formação de tecido ósseo pela não reabsorção do material. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Made available in DSpace on 2014-10-09T12:45:47Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:17Z (GMT). No. of bitstreams: 1 07149.pdf: 7899411 bytes, checksum: 6ba368602f98f29e9401ef54276cdb45 (MD5) / Tese (Doutoramento) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN/CNEN-SP

Submitted by Claudinei Pracidelli (cpracide@ipen.br) on 2015-06-09T18:22:48Z No. of bitstreams: 0 / Made available in DSpace on 2015-06-09T18:22:49Z (GMT). No. of bitstreams: 0 / O presente trabalho teve como objetivo utilizar a técnica nuclear de Correlação Angular γ-γ Perturbada (CAP) para a medida de interações hiperfinas em filmes finos e amostras em pó de óxidos semicondutores SnO2 e TiO2 puros e dopados com metais de transição para uma investigação sistemática de defeitos estruturais e do magnetismo sob o ponto de vista atômico tendo como principal motivação a candidatura à aplicação desses óxidos em spintrônica. O trabalho também teve como foco a preparação e caracterização das amostras por meio de técnicas convencionais, como difração de raios X, microscopia eletrônica de varredura, espectroscopia de energia dispersiva e medidas de magnetização. Amostras puras dos filmes foram medidas mediante a variação sistemática da temperatura de tratamento térmico e do campo magnético aplicado. Tais medidas foram realizadas no HISKP, na Universidade de Bonn (Rheinische Friedrich-Wilhelms-Universität Bonn), através de implantação de íons de 111In(111Cd) ou 181Hf(181Ta); no IPEN, por sua vez, essas medidas foram realizadas após a difusão dos mesmos núcleos de prova. Outra parte das medidas CAP foram feitas através de implantação de íons de 111mCd(111Cd) e 117Cd(117In) no Isotope Mass Separator On-Line (ISOLDE) do Centre Européen Recherche Nucléaire (CERN). As medidas foram realizadas nos intervalos de temperatura de 8 K a 1173 K. Para análise de ferromagnetismo, medidas foram feitas à temperatura ambiente com e sem aplicação de campo magnético externo. Após a comparação dos resultados das medidas macroscópicas e atômicas das amostras, foi possível concluir que há uma correlação entre os defeitos, o magnetismo e a mobilidade dos portadores de carga nos semicondutores aqui estudados. Um passo adiante na busca de semicondutores, cujo ordenamento magnético possibilite o seu uso na eletrônica baseada em spin. Alguns resultados já foram publicados, incluindo resultados obtidos na Universidade de Bonn durante o período de doutorado sanduíche [1-7]. / Tese (Doutorado em Tecnologia Nuclear) / IPEN/T / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

>Magister Scientiae - MSc / In this study PbSe quantum dots (QDs) were successfully synthesized via the organometallic and aqueous routes. Optical characterization was carried out using photoluminescence (PL) spectroscopy, structural and morphological characterization were carried out using X-ray diffraction (XRD) and transmission electron microscopy (TEM). Energy-dispersive X-ray spectroscopy (EDS) was used to determine the composition of the QDs. All the synthesized QDs were found to have emissions within the near-infrared region of the spectrum (≥1000 nm) with most of them being less than 5 nm in size. The aqueous synthesized QDs had a perfect Gaussian emission spectrum with a FWHM of ~23 nm indicating pure band gap emission and narrow size distribution respectively. The QDs were determined to have a cubic rock-salt crystal structure consistent with bulk PbSe. The aqueous synthesized QDs were however not stable in solution with the QDs precipitating after approximately 48 h. The organometallic synthesized QDs were transferred into the aqueous phase by exchanging the surface oleic acid ligands with 11-mercaptoundecanoic acid ligands. The ligand exchanged QDs were however stable in solution for over two weeks. The effects of reaction parameters on the optical and structural properties of the organometallic synthesized QDs were investigated by varying the reaction time, temperature, ligand purity, lead and selenium sources. It was observed that larger QDs were formed with longer reaction times, with reactions proceeding faster at higher reaction temperatures than at lower temperatures. Varying the ligand purity was found to have minimal effects on the properties of the synthesized QDs. The lead and selenium sources contributed largely to the properties of the QDs with lead oxide producing spherical QDs which were smaller compared to the cubic QDs produced from lead acetate. TBPSe was seen to produce smaller QDs as compared to TOPSe. The cytotoxity of the synthesized QDs was determined following the WST-1 cell viability assay with the QDs being found to be non-toxic at all the tested concentrations

This thesis concerns my theoretical calculations and simulations in comparison with experimental measurements acquired by means of surface science techniques on bare surfaces and molecules adsorbed on surfaces. In the beginning of the thesis I briefly describe the density functional theory (DFT) method, which is used for calculations of geometric and electronic structure of surfaces and absorbed molecules. It is followed by a quick overview of the scanning probe microscopy (SPM) and X-ray spectroscopy techniques that provided experimental context for my calculations. In the later part of my thesis I introduce publications on which I participated. In these works, direct results of my DFT calculations or simulations based on DFT outputs helped to reveal geometric and electronic structure of acetophenone adsorbed on Si(111) surface, on-surface oligomerized organic molecules and boron atoms used for substitational doping of graphene. The simulations also enable us to probe a laser initiated CO hydrogenation in real time. A big part of my work was the development of some simulation methods for SPM imaging of molecules on surfaces with flexible tip apexes. These simulation methods helped to create a comprehensive overview of SPM techniques performed with flexible tip apexes. 1

According to the 2019 Canadian infrastructure report card, a concerning amount of municipal infrastructure is in poor or very poor condition. The infrastructure in this condition requires immediate action for rehabilitation or replacement. For concrete infrastructure, an effective repair can extend its service life and ensure that the services it provides continue to meet the community expectations. However, unfavorable environmental factors such as repeated/cyclic loads and freezing and thawing cycles adversely affect the bond between substrate concrete and repair materials, which lowers the structural capacity of repaired structures. So far, researchers have found that bond strength of repair can be affected by surface roughness, surface moisture, chemical adhesion or cohesion, curing regime, properties of substrate and repair materials, use of bond agent, and curing regimes. These findings are mostly based on the studies that focused on cold-jointed cylinders or beams, but in real-life repair situations, repairs of beams or slabs are located at either tension or compression side of the structure. Currently, there is no comprehensive study that investigates the bond of concrete repair under a combination of freezing and thawing and repeated/cyclic loading conditions. In addition, it is challenging to provide a rapid and non-destructive evaluation of the bond deterioration of repair materials. To address these issues systematically, this dissertation breaks the task into four phases. Phase (I) focuses on the development of an engineered “crack-free” repair mix that contains polypropylene (PP) fiber. A novel method is used to surface treat the PP fibers with supplementary cementitious materials. The effectiveness of surface-treating fibers for improved bond strength and reduced cracking is investigated. The compressive, tensile, and flexural strength of this engineered repair mix are determined and compared with two commercially available repair materials. The results from Phase I show that by adding 0.2% (by weight) Metakaolin-treated fibers into concrete mix, the compressive strength improves by up to 15.7% compared to mixes with untreated fibers. This study achieved a strength increase of 13.5% as compared to the reported 3.3% in other studies that use 25 times the amount of metakaolin used in this study. The experimental results confirm that at 0.2% dosage level, the use of novel surface treating technique is a cost-effective way to improve the strength of repair materials. Phase (II) focuses on characterizing the bond strength of various repair systems after freezing-thawing (FT) damage using both non-destructive and destructive methods. Two innovative sounding methods, which overcome the subjectivity of the traditional chain drag method, are used to evaluate FT damage non-destructively. In the experimental study, beams with a U-shaped cut are made to simulate conditions experienced by a concrete structure during a typical repair project. Three types of repair materials are used including cementitious repair concrete, cementitious repair mortar, and polymer-modified cementitious mortar. After up to 300 cycles of freeze-thaw exposure, resonant frequency and bond flexural strength of the prismatic specimens are determined. The empirical equations relating Non-destructive test (NDT) measurements and flexural bond strength of the repaired structures after freeze-thaw (FT) exposure are proposed. The results from Phase II show that the change in dynamic modulus of elasticity determined from NDTs agrees well with the change in other measurements including flexural bond strength, interfacial crack width, and mass loss after freeze-thaw exposure. In this study, linear relationships are established between dynamic modulus of elasticity and flexural bond strength for both cementitious and polymer-modified cementitious repair mortar with a coefficient of determination ranging between 0.87 and 0.95. The proposed empirical models can be used to predict bond flexural strength of repaired structures based on NDT measurement. Also, it was found that the samples repaired with polymer-modified cementitious mortar (Mix P) have superior FT resistance compared to other repaired samples. Phase (III) focuses on investigating the structural capacity and bond performance of repaired beams after cyclic/repeated loading. To accelerate the test process, a novel modified loading regime consisting of cycle groups of increasing cyclic/repeated stress amplitude is proposed. The models proposed by literature and current codes and standards are used to validate the results. Phase (IV) focuses on the development of the damage models for both individual and combined FT and cyclic loading exposure on repaired concrete structures. The results in phase III show the feasibility of using the Palmgren-Miner rule and Goodman linear model to estimate the fatigue life of repaired structures. This was confirmed within the context of this study. This study established the usefulness of using groups of increasing cyclic stress amplitude to accelerate the fatigue test process. The two-million cycle fatigue endurance limit estimated using cycle groups of Mix S (70.8%) was very similar to what was reported in the literature (71%) using the traditional time-consuming cyclic loading method. This study found that the formulas proposed by CSA 23.3 can effectively predict the moment resistance of both intact (control) and repaired RC beams. The ratio of experimental moment resistance values to its predictions ranges from 0.91 to 1.04. Based on the experimental results of previous three phases, an empirical model that predicted the fatigue service life of FT-damaged concrete structures is proposed. Future research requires a more comprehensive study on the FT performance of various polymer-modified cementitious mortars of different mix designs in repairing concrete structures. By increasing the number of tested specimens, a better relationship could be established between destructive and NDT methods. Future research is also required to explore the combined effect of FT and cyclic loading on repaired RC structures experimentally. / Graduate / 2023-03-22

No description available.

The discovery of superconductivity in iron-based pnictides in 2008 gave rise to a high advance in the research of high-temperature superconductors. But up to now there is no generally admitted theory of the non-BCS mechanism of these superconductors. The electron and hole doped Ba122 (BaFe2As2) compounds investigated in this thesis are supposed to be suitable model systems for studying the electronic behavior in order to shed light on the superconducting mechanisms. The 3d-transiton metal doped Ba122 compounds are investigated using the X-ray photoelectron spectroscopy (XPS), X-ray absorption spectroscopy (XAS), X-ray emission spectroscopy (XES) and X-ray magnetic circular dichroism (XMCD), while the completely hole doped K122 is observed using XPS. The experimental measurements are complemented by theoretical calculations. A further new class of superconductors is represented by the electride 12CaO*7Al2O3: Here superconductivity can be realized by electrons accommodated in the crystallographic sub-nanometer-sized cavities, while the mother compound is a wide band gap insulator. Electronic structure investigations, represented by XPS, XAS and resonant X-ray photoelectron spectroscopy (ResPES), carried out in this work, should help to illuminate this unconventional superconductivity and resolve a debate of competing models for explaining the existence of superconductivity in this compound.

[ES] El propósito primordial de esta Tesis Doctoral se fundamenta en poner en valor y difundir el legado de la producción artística y la biografía del pintor alzireño, Teodoro Juan Andreu Sentamans (Alzira, 1870 - Valencia, 1935), con la finalidad de cubrir las lagunas historiográficas existentes hasta la actualidad y aportar datos documentales inéditos de su trayectoria artística. El reconocimiento del artista hasta la fecha ha estado subyugado a haber sido discípulo del gran Joaquín Sorolla y Bastida, sin que se haya contemplado y haber tenido en cuenta su importante actividad artística y docente, sus comisariados en exposiciones, particulares y de otros artistas; su participación asidua en exposiciones nacionales e internacionales, siendo galardonado en varias de ellas; ni el logro de proyectos importantes atribuidos a otras figuras, o simplemente olvidados. Dos circunstancias han confluido para propiciar la inmerecida desatención a la obra de Andreu: ser coetáneo a su maestro, Sorolla, y ser fiel a su estilo costumbrista, negándose a evolucionar hacia una pintura más avanzada. En consecuencia, y fruto del vacío historiográfico, surge la necesidad de realizar este profundo trabajo de investigación, mediante el cual se quiere reivindicar su actividad artística desarrollada entre finales del siglo XIX y principios del XX. Para ello se ha confeccionado un inventario general de gran parte de su producción artística clasificado según la etapa cronológica, y un catálogo razonado de sus obras más relevantes mediante la elaboración de unas fichas técnicas. Debido a la estrecha relación existente entre Sorolla y Andreu se ha llevado a cabo un estudio analítico de una parte representativa de su producción artística, dilucidando, mediante la obtención de resultados y comparativas con la obra seleccionada de Joaquín Sorolla, si el pintor Teodoro Andreu siguió los pasos de su maestro, o utilizó su propia metodología en el uso de la teoría del color y sus pigmentos. Por lo tanto, en este trabajo también se ha elaborado un estudio de los pigmentos utilizados por Andreu en una parte de su obra: análisis realizados por espectrometría de fluorescencia de Rayos X dispersiva en energía (EDXRF), cuyos resultados aportan datos y conclusiones inéditas y determinantes en la obra de Andreu. Uno de los resultados propiciados en esta investigación ha sido que un alto porcentaje de su obra se encuentra localizada en colecciones privadas. En base a esta realidad se ha confeccionado, mediante un programa informático, un museo virtual donde se recoge parte importante de la obra "escondida", a través de una plataforma digital exprofeso, aportando un repertorio de contenidos digitales sustentado con la documentación aportada en este trabajo de investigación, ofreciendo la posibilidad de realizar un recorrido museográfico virtual donde el visitante puede disfrutar de la obra sita en colecciones particulares / [CA] El propòsit primordial d'aquesta Tesi Doctoral es fonamenta a posar en valor i difondre el llegat de la producció artística i la biografia del pintor alzireny, Teodoro Juan Andreu Sentamans (Alzira, 1870 - València, 1935), amb la finalitat de cobrir les llacunes historiogràfiques existents fins a l'actualitat i aportar dades documentals inèdites de la seua trajectòria artística. El reconeixement de l'artista fins hui ha estat subjugat a haver sigut deixeble del gran Joaquín Sorolla i Bastida, sense que s'haja contemplat i haver tingut en compte la seua important activitat artística i docent, els seus comissariats en exposicions, particulars i d'altres artistes; la seua participació assídua en exposicions nacionals i internacionals, sent guardonat en diverses d'elles; ni l'assoliment de projectes importants atribuïts a altres figures, o simplement oblidats. Dues circumstàncies han confluït per a propiciar la immerescuda desatenció a l'obra d'Andreu: ser coetani al seu mestre, Sorolla, i ser fidel al seu estil costumista, negant-se a evolucionar cap a una pintura més avançada. En conseqüència, i fruit del buit historiogràfic, sorgeix la necessitat de realitzar aquest profund treball de recerca, mitjançant el qual es vol reivindicar la seua activitat artística desenvolupada entre finals del segle XIX i principis del XX. Per a això s'ha confeccionat un inventari general de gran part la seua producció artística classificat segons l'etapa cronològica, i un catàleg raonat de les seues obres més rellevants mitjançant l'elaboració d'unes fitxes tècniques. A causa de l'estreta relació existent entre Sorolla i Andreu s'ha dut a terme un estudi analític d'una part representativa de la seua producció artística, dilucidant, mitjançant l'obtenció de resultats i comparatives amb l'obra seleccionada de Joaquín Sorolla, si el pintor Teodoro Andreu va seguir els passos del seu mestre, o va utilitzar la seua pròpia metodologia en l'ús de la teoria del color i els seus pigments. Per tant, en aquest treball també s'ha elaborat un estudi dels pigments utilitzats per Andreu en una part de la seua obra: anàlisis realitzades per espectrometria de fluorescència de Raigs X dispersiva en energia (EDXRF), els resultats dels quals aporten dades i conclusions inèdites i determinants en l'obra d'Andreu. Un dels resultats propiciats en aquesta investigació ha sigut que un alt percentatge de la seua obra es troba localitzada en col·leccions privades. Sobre la base d'aquesta realitat s'ha confeccionat, mitjançant un programa informàtic, un museu virtual on es recull una part important de l'obra "amagada", mitjançant una plataforma digital exprofeso, aportant un repertori de continguts digitals sustentat amb la documentació aportada en aquest treball de recerca, oferint la possibilitat de realitzar un recorregut museogràfic virtual on el visitant pot gaudir de l'obra situada en col·leccions particulars. / [EN] The main purpose of this Doctoral Thesis is based on valuing and expanding the legacy of the artistic production and the biography of the painter from Alzira, Teodoro Juan Andreu Sentamans (Alzira, 1870 - Valencia, 1935) in order to cover the existing historiographical gaps up to the present day and provide unpublished documentary data on his artistic career. Up to the present moment, the recognition of the artist has been subjugated to having been a disciple of the great Joaquín Sorolla y Bastida, without having contemplated and taken into account his important artistic and teaching activity, his curatorships in exhibitions, individuals and other artists; his regular participation in national and international exhibitions, being awarded in several of them; nor the achievement of important projects attributed to other artists, or simply forgotten. Two circumstances have come together to promote undeserved neglect of Andreu's work: being a contemporary of his teacher, Sorolla, and being faithful to his traditional style, refusing to evolve towards a more advanced painting. Consequently, as a result of the historiographical gap, the need of carrying out this deep research arises now. Through it, I want to vindicate Andreu's artistic activity developed between the end of the 19th century and the beginning of the 20th century. For this, a general inventory of all his work has been made, artistic production classified according to the chronological stage, and a reasoned catalog of his most relevant works through the preparation of technical sheets. Due to the close relationship between Sorolla and Andreu, an analytical study of a representative part of his artistic production has been carried out, elucidating, by obtaining results and comparisons with the selected work of Joaquín Sorolla, whether the painter Teodoro Andreu followed the footsteps of his teacher, or used his own methodology in the use of colour theory and its pigments. Therefore, this work has also carried out a study of the pigments used by Andreu in part of his work; analysis carried out by energy dispersive X-ray fluorescence spectometry (EDXRF), whose conclusions in Andreu's work. One of the results fostered in this investigation has been that a high percentage of his work is located in private collections, base don this reality, a virtual museum has been created through a computer programme where all the "hidden" work is collected. Through a digital platform expressly made, it provides a repertoire of digital content supported by the documentation provided in this research work, offering the possibility of taking a virtual museum tour where the visitor can enjoy the work located in private collections. / Ibáñez Bartolomé, M. (2023). Teodoro Andreu Sentamans (1870-1935): Catalogación y estudio analítico de su producción artística [Tesis doctoral]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/195349

This thesis deals with the analysis of nano-structured layers deposited by high-frequency magnetron sputtering on the monocrystalline silicon surface. The content of the work focuses on the magnetron sputtering application as an alternative method for passivation and antireflection layers deposition of silicon solar cells. The procedure of pre-deposite silicon surface cleaning by plasma etching in the Ar/H2 gas mixture atmosphere is suggested. In the next step the silicon nitride and aluminum nitride layers with hydrogen content in Ar/N2/H2 gas mixture by magnetron sputtering are deposited. One part of the thesis describes an experimental pseudo-carbide films deposition from a silicon target in the atmosphere of acetylene (C2H2). An emphasis is placed on the research of sputtered layers properties and on the conditions on the silicon-layer interface with the help of the standard as well as special measurement methods. Sputtered layers structure is analyzed by modern X-ray spectroscopy (XPS) and by Fourier infrared spectroscopy (FTIR). Optical ellipsometry and spectrophotometry is used for the diagnostic of the layers optical properties depending upon the wavelength of incident light. A special method of determining the surface lay-out of the charge´s carrier life in the volume and on the surface of silicon is employed to investigate the passivating effects of the sputtered layers.