<p>A molecular system capable of photoinduced water splitting is an attractive approach to solar energy conversion. This thesis deals with the functional characterization of molecular building blocks for the three principal functions of such a molecular system: Photoinduced accumulative charge separation, catalytic water oxidation, and catalytic proton reduction. </p><p>Systems combining a ruthenium-trisbipyridine photosensitizer with multi-electron donors in form of dinuclear ruthenium or manganese complexes were investigated in view of the rate constants of electron transfer and excited state quenching. The kinetics were studied in the different oxidation states of the donor unit by combination of electrochemistry and time resolved spectroscopy. The rapid excited state quenching by the multi-electron donors points to the importance of redox intermediates for efficient accumulative photooxidation of the terminal donor.</p><p>The redox behavior of manganese complexes as mimics of the water oxidizing catalyst in the natural photosynthetic reaction center was studied by electrochemical and spectroscopic methods. For a dinuclear manganese complex ligand exchange reactions were studied in view of their importance for the accumulative oxidation of the complex and its reactivity towards water. With the binding of substrate water, multiple oxidation in a narrow potential range and concomitant deprotonation of the bound water it was demonstrated that the manganese complex is capable of mimicking multiple aspects of photosynthetic water oxidation.</p><p>A dinuclear iron complex was investigated as biomimetic proton reduction catalyst. The complex structurally mimics the active site of the iron-only hydrogenase enzyme and was designed to hold a proton on the bridging ligand and a hydride on the iron centers. Thermodynamics and kinetics of the protonation reactions and the electrochemical behavior of the different protonation states were studied in view of their potential catalytic performance.</p>

A molecular system capable of photoinduced water splitting is an attractive approach to solar energy conversion. This thesis deals with the functional characterization of molecular building blocks for the three principal functions of such a molecular system: Photoinduced accumulative charge separation, catalytic water oxidation, and catalytic proton reduction. Systems combining a ruthenium-trisbipyridine photosensitizer with multi-electron donors in form of dinuclear ruthenium or manganese complexes were investigated in view of the rate constants of electron transfer and excited state quenching. The kinetics were studied in the different oxidation states of the donor unit by combination of electrochemistry and time resolved spectroscopy. The rapid excited state quenching by the multi-electron donors points to the importance of redox intermediates for efficient accumulative photooxidation of the terminal donor. The redox behavior of manganese complexes as mimics of the water oxidizing catalyst in the natural photosynthetic reaction center was studied by electrochemical and spectroscopic methods. For a dinuclear manganese complex ligand exchange reactions were studied in view of their importance for the accumulative oxidation of the complex and its reactivity towards water. With the binding of substrate water, multiple oxidation in a narrow potential range and concomitant deprotonation of the bound water it was demonstrated that the manganese complex is capable of mimicking multiple aspects of photosynthetic water oxidation. A dinuclear iron complex was investigated as biomimetic proton reduction catalyst. The complex structurally mimics the active site of the iron-only hydrogenase enzyme and was designed to hold a proton on the bridging ligand and a hydride on the iron centers. Thermodynamics and kinetics of the protonation reactions and the electrochemical behavior of the different protonation states were studied in view of their potential catalytic performance.

The bulk metallic glasses (BMGs) are potential metallic materials due to their interesting properties, such as the high strength, high elastic strain limit, and high wear/corrosion resistance. Over the past four decades, a variety of studies have been done on the characteristics of the mechanical, thermodynamic properties of such category of metallic materials, but there still remain many questions about basic deformation mechanisms and their microstructures so far. Molecular dynamics (MD) simulation can provide significant insight into material properties under the atomic level and see a detailed picture of the model under available investigation in explaining the connection of macroscopic properties to atomic scale. MD simulation is applied to study the material properties and the deformation mechanisms in various binary metallic glasses and intended to examine the feasibility of MD simulation to compare the experimental results obtained in our laboratory over the past few years. The gradual vitrification evolution of atom mixing and local atomic pairing structure of the binary Zr-Ni, Zr-Ti alloys and pure Zr element during severe deformation at room temperature is traced numerically by molecular dynamic simulation. It is found that the icosahedra clusters will gradually develop with the increasing of disorder environment of alloys in the Zr-Ni, Zr-Ti systems, forming amorphous atomic packing. Other compound-like transition structures were also observed in transient in the Zr-Ni couple during the solid-state amorphization process under severe plastic deformation. The crystalline pure Zr can be vitrified in the simulation provided that the rolling speed is high enough and the rolling temperature is maintained at around 300 K. On the other hand, the effective medium theory (EMT) inter-atomic potential is employed in the molecular dynamics (MD) simulation to challenge the study of the diffusion properties in the Mg-Cu thin films. The transition of local structures of Mg-Cu thin films is traced at annealing temperatures of 300, 413, and 500 K. Furthermore, the simulation results are compared with the experimental results obtained from the transmission electron microscopy and X-ray diffraction. The gradual evolution of the local atomic pairing and cluster structure is discussed in light of the Mg and Cu atomic characteristics. Lately, the progress of the cyclic-fatigue damage in a binary Zr-Cu metallic glass in small size scale is investigated using classical molecular-dynamics (MD) simulations. The three-dimensional Zr-Cu fully amorphous structure is produced by quenching at a cooling rate 5 K/ps (ps = 10-12 s-1) from a high liquid temperature. The Nose-Hoover chain method is used to control the temperature and pressure to maintain a reasonable thermodynamic state during the MD-simulation process, as well as to bring the imposed cyclic stress on the subsequent simulation process. Both the stress- and strain-control cyclic loadings are applied to investigate the structural response and free-volume evolution. The overall structure would consistently maintain the amorphous state during cyclic loading. The plastic deformation in simulated samples proceeds via the network-like development of individual shear transition zones (STZs) by the reversible and irreversible structure-relaxations during cyclic loading, dislike the contribution of shear band in large-scale specimens. Dynamic recovery and reversible/irreversible structure rearrangements occur in the current model, along with annihilation of excessive free volumes. This behavior might be able to retard the damage growth of metallic glass and enhance their fatigue life.

Photoinduced electron transfer is involved in a number of photochemical and photobiological processes. One example of this is photosynthesis, where the absorption of sunlight leads to the formation of charge-separated states by electron transfer. The redox equivalents built up by successive photoabsorption and electron transfer is further used for the oxidation of water and reduction of carbon dioxide to sugars. The work presented in this thesis is part of an interdisciplinary effort aiming at a functional mimic of photosynthesis. The goal of this project is to utilize sunlight to produce renewable fuels from sun and water. Specifically, this thesis concerns photoinduced electron transfer in donor(D)-photosensitizer(P)-acceptor(A) systems, in mimic of the primary events of photosynthesis. The absorption of a photon typically leads to transfer of a single electron, i.e., charge separation to produce a single electron-hole pair. This fundamental process was studied in several molecular systems. The purpose of these studies was optimization of single electron transfer as to obtain charge separation in high yields, with minimum losses to competing photoreactions such as energy transfer.Also, the lifetime of the charge separated state and the confinement of the electron and hole in three-dimensional space are important in practical applications. This led us to explore molecular motifs for linear arrays based on Ru(II)bis-tridentate and Ru(II)tris-bidentate complexes. The target multi-electron catalytic reactions of water-splitting and fuel production require a build-up of redox equivalents upon successive photoexcitation and electron transfer events. The possibilities and challenges associated with such processes in molecular systems were investigated. One of the studied systems was shown to accumulate two electrons and two holes upon two successive excitations, without sacrificial redox agents and with minimum yield losses. From these studies, we have gained better understanding of the obstacles associated with step-wise photoaccumulation of charge and how to overcome them.

The Thesis analyzes one of the spheres of alternative energy supply – the solar energy. The main objective of the Thesis is to determine the energy rates of the solar collector and its accumulative capacity. The Paper introduces a stand on the solar collector research which consists of a flat solar collector, heat accumulator and auxiliary equipment. The research object of the Thesis is a laboratory flat solar collector and its system. The Thesis analyses the constructions of the solar collector which is meant for water heating. For this purpose theoretical research has been made, and experimental tests have been performed in a confined room by using a simulator of solar radiation and blowing the solar collector at an average wind speed of 2 m/s. Tests on the energy characteristics of the solar collector have been performed by using transparent poly-carbon covering and the glass covering; without using transparent covering and changing the debit of the heat-carrier. The author has made the reliance of the solar collector and accumulative capacity on the in-flowing and out-flowing heat-carrier and differences of the environment temperatures by using different coverings and debits of the heat-carrier. The relation between the accumulative capacity of the solar collector and the dimension of the solar collector has been established.

Ein Verbundwerkstoff aus Titan und Aluminium kann mittels akkumulativem Walzplattieren hergestellt werden. Dabei wird die Dehngrenze angehoben, wenn die Titanlagen nicht abschnüren, sondern laminar bleiben. Die Herstellung eines laminaren Ti/Al-Verbundwerkstoffes ist neu gegenüber den bisherigen Studien. Diese Dissertation beschreibt die Hindernisse und Lösungen, die aus metallphysikalischer Überlegung entstanden und praktisch umgesetzt worden sind. Bei der starken Umformung je ARB-Zyklus neigt das Titan bereits beim zweiten Walzen zur Bildung von Einschnürungen. Das kann durch eine Verringerung der Dickenreduktion je Zyklus sowie durch eine Erhöhung der Verfestigungsrate unterdrückt oder verzögert werden. Walzen mit unterschiedlich großen Ober- und Unterwalzen führt im Vergleich zum symmetrischen Walzen bei gleicher Dickenreduktion zu verstärktem Einschnüren der Titanlagen. Da der Prozess jedoch eine Verringerung der Dickenreduktion erlaubt, ermöglicht er die Zahl der Einschnürungen bei gegenüber dem Quartowalzen gleicher Geschwindigkeit zu verringern. Die spezifische Festigkeit erreicht hierbei einen Wert von auf dem Niveau hochfester Stähle.

This paper aims to propose a discussion about the core elements of bureaucratic- authoritarian state theory of the argentine political scientist Guillermo O'Donnell. Analyzing the economic and political interpretations that permeate their way of thinking and the resulting implications in power relations caused by the economic structuring approach. The historical cases traversed by this kind of rule will be examined, overall, through the concepts and correlations, which allow the direction for the bureaucratic - authoritative forms, likewise the post- strokes standards to allow consideration the dynamic power compared to such types. In particular, comparing disaggregated the standards set in the experiences Brazil and Chile. The nodal axis of this research seeks to reframe the political, economic and institutional trajectory explained the theory of bureaucratic- authoritarian state reflecting on the types of conflicts arising in this type of domination as well as discussing fundamentally the place of common development derived from the economic structure accumulative proposed by the author . / O presente trabalho procura propor uma discussão acerca dos elementos centrais da teoria de Estado burocrático-autoritário do cientista político argentino Guillermo O´Donnell. Analisando as interpretações econômicas e políticas que permeiam sua linha de pensamento e as decorrentes implicâncias nas relações de poder causadas pelo enfoque de estruturação econômica. Os casos históricos atravessados por esta espécie de dominação serão examinados, no global, através dos conceitos e correlações que permitem a direção para as formas burocrático-autoritárias, do mesmo modo, os padrões pós-golpes, que permitem ponderar a dinâmica de poder comparada de tais tipos. Em particular, comparando de forma desagregada os padrões estabelecidos nas experiências de Chile e do Brasil. O eixo nodal da presente pesquisa procura re-significar a trajetória política, econômica e institucional explicitada na teoria do Estado burocrático-autoritário refletindo sobre os tipos de conflitos suscitados neste tipo de dominação assim como discutir, fundamentalmente, o lugar de desenvolvimento comum derivado da estruturação econômica acumulativa proposta pelo autor.

O presente trabalho teve como objetivo a caracterização mecânica, microestrutural e inspeção fratográfica do compósito de matriz de alumínio Al-1100 reforçado com partículas de carbeto de silício-SiC (40 &#956;m) fabricados por meio de laminação acumulativa (ARB- do inglês Accumulative Roll Bonding), assim como, para efeito comparativo, foram estudados o Al-1100 processado por ARB sem adição de partículas e Al-1100 como recebido. Ensaio de desgaste microadesivo com esfera fixa e ensaio de tração unidirecional quase estático que foram realizados em amostras sem entalhes e em amostras contendo diferentes geometrias de entalhe. Microscopia óptica, microscopia eletrônica de varredura nos modos: elétrons secundários, elétrons retroespalhados, espectroscopia de energia dispersiva por raios-X e difração de elétrons retroespalhados, difração de raios-X e microtomografia computadorizada foram utilizados para caracterizar as amostras. Os resultados obtidos mostraram êxito da incorporação de partículas de SiC na matriz de Alumínio por meio do processo ARB. Houve ganhos relevantes na resistência máxima à tração, na rigidez e na deformação máxima no momento da ruptura, devido à incorporação de SiCp. Essas propriedades foram bastante influenciadas na presença de concentradores de tensão (entalhes). A resistência ao desgaste do compósito foi excepcionalmente incrementada comparativamente aos demais materiais. Todos os resultados foram corroborados pelas análises microetrutural e fratográficas. / The present study aims to characterize mechanical, microstructural and through fractographic inspection laminates Al-1100 aluminum matrix composite reinforced with silicon carbide particles, SiCp (40 &#956;m), manufactured by accumulative roll bonding (ARB), as well as, for comparative effect, were studied Al-1100 processed by ARB without the addition of particles and Al-1100 received. Micro-adhesive wear test with fixed ball and test almost static unidirectional traction were performed on samples without scoring, and in samples containing different geometries notches. Optical microscopy, scanning electron microscopy modes: secondary electrons, backscattered electrons, energy dispersive X-ray and electron backscatter diffraction, X-ray diffraction and computed microtomography, these were used to characterize the samples. The results indicated successful incorporation of SiC particles in the aluminum matrix by ARB process. There have been significant gains in maximum tensile strength, stiffness and maximum deformation at the time of rupture, due to incorporation of SiCp. These properties were strongly influenced in the presence of stress concentrators (notches). The resistance of the composite wear was exceptionally increased compared to Al-1100 ARB. All results were corroborated by microstructural and fractographics analysis.

Submitted by Isaac Francisco de Souza Dias (isaac.souzadias@ufpe.br) on 2016-03-02T19:08:33Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese José Ferraz.pdf: 2743054 bytes, checksum: 9154337dac4a587934aab71697b77a90 (MD5) / Made available in DSpace on 2016-03-02T19:08:33Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Tese José Ferraz.pdf: 2743054 bytes, checksum: 9154337dac4a587934aab71697b77a90 (MD5) Previous issue date: 2008-05-29 / CNPQ / Neste trabalho, utilizamos as técnicas de controle temporal coerente e de manipulação da fase óptica do campo óptico para investigar e controlar os diferentes caminhos quânticos induzidos em transições de dipolo elétrico envolvendo a absorção de dois fótons no átomo de rubídio. As transições foram excitadas por pares de pulsos de separação temporal variável e analisamos a resposta do meio atômico em função dessa separação. Três situações experimentais são analisadas envolvendo transições com diferentes características. No primeiro experimento, utilizamos luz incoerente de um laser de corante com duração temporal de nanosegundos, mas com tempo de coerência de picosegundos, para excitar a transição de dois fótons, envolvendo níveis altamente excitados, níveis de Rydberg. A resposta do sistema é analisada através de um processo de mistura de quatro ondas, resolvida no tempo, e a seleção dos diferentes caminhos quânticos envolvidos no processo é feita a partir do controle da polarização dos campos do laser incidente. Interferências na freqüência central do laser, interferências "ópticas", e no dobro dessa freqüência, interferências quânticas, são observadas. Nos outros dois estudos, a transição de dois fótons é excitada por pulsos com duração temporal da ordemde 100 fentosegundos. No primeiro caso, investigamos uma transição de dois fótons pura, entre os níveis 5S e 7S do rubídio, onde uma fase externa, dependente da freqüência, é adicionada em um dos pulsos, enquanto o outro tem seu atraso temporal controlado. A fluorescência detectada é uma medida direta da população do estado excitado. Novamente, um sinal interferométrico é observado, cujo controle coerente é efetuado por uma combinação da fase externa e do atraso temporal. O último experimento envolve uma transição seqüencial, cuja ressonância de um fóton leva a efeitos de propagação observados no sinal de interesse. Outro aspecto importante é que a taxa de repetição do laser era maior que as taxas de relaxação dos níveis envolvidos, de forma que efeitos de acumulação na população e na coerência também estão presentes. A resposta do sistema é analisada através do processo de mistura paramétrica de quatro ondas, resolvido no tempo. O sinal interferométrico, com controle de polarização e da freqüência de detecção, permite uma demonstração clara da origem quântica nas interferências "ópticas". / In this work, we use the techniques of temporal coherent control and phase manipulation of the optical field to investigate and control different quantum pathways in the two-photon absorption in rubidium atoms. Three experimental situations are studied involving transitions with different characteristics. In all of them, the medium response is analyzed as a function of the temporal delay between the pulse pairs responsible for the two-photon transition. In the first experiment, we use incoherent light from a dye laser with pulse duration in the nanosecond scale, but with coherence time in the picosecond scale, to excite the two-photon transition, which involves highly excited levels, Rydberg states. The system response is analyzed through a time-resolved four-wave mixing process, and the quantum pathway selection is realized by polarization control of the incident laser fileds. Interferences in the central laser frequency - "optical" interferences - and at twice this frequency - quantum interferences - are observed. In the subsequent two studies, the two-photon transition is excited with 100 fs pulses. In the first case, we investigate a pure two-photon transition, the 5S - 7S rubidium transition, where an external frequency depedent phase is added in one pulse, while the temporal delay of a second pulse is controlled. We observe an interferometric signal, in which coherent control is achieved with external phase and temporal delay combination. The last experiment involves a sequential transition, which has a one-photon resonance that leads to propagation effects observed in the signal. The laser repetition rate is greater than the atomic system relaxation rates, leading to accumulation effects in the population and coherence, which leads to important effects. A time-resolved parametric four-wave mixing is used to investigate the system response. The interferometric signal, with polarization and detection frequency control, allows us to clearly demonstrate the quantum origin of the "optical" interferences.

This thesis deals with object tracking in video sequence. It focuses on studying of one object´s motion in static background. Motion is defined by its direction and its speed. It was created 3 operators in RapidMiner to determine it. The operator called AccumulativeDifferenceImage searches a trajectory of motion by technique of accumulative difference image. Operator called OpticalFlow is created to describe type of motion and to find size of location´s transition. The operator called SpeedMeasuing is used for determining of speed, it calculates speed of object by using input´s binary masks in meters by second. In theoretical part of thesis are described the types of segmentation´s methods, basic types of block matching algorithms, attributes of video sequences and problem of recording of motions. In practical part are described implementations of every operator, the testing video sequences and showed results of tests for every operator.