Baigiamajame magistro darbe nagrinėjamos plazminio purškimo Ni ir Co pagrindo dangų ant aliuminio substrato savybės. Atlikta terminio purškimo dangų, jų technologijų apžvalga ir analizė bei pateikta dangų tyrimo metodika. Atlikti šių dangų mikrostruktūros, porėtumo, adhezijos, mikrokietumo ir dangos tamprumo modulio tyrimai. Baigiamajame darbe sudaryta purkštinės dangos skaitinio modeliavimo metodika ir gauti rezultatai pateikti grafiškai. Išnagrinėjus praktinius ir skaitinius terminio purškimo dangų rezultatus, pateikiamos baigiamojo darbo išvados. Darbą sudaro 4 dalys: įvadas, literatūros šaltinių apžvalga ir analizė, Ni ir Co pagrindo plazminio purškimo dangų savybių ir mikrostruktūros eksperimentiniai tyrimai, purkštinės dangos skaitinio modeliavimo tyrimas, tyrimo rezultatai ir jų aptarimas, išvados, literatūros sąrašas. / In the final master thesis the plasma spraying of Ni and Co base coatings on aluminum substrate properties are analyzed. The review of thermal spray coatings technology and research methods are described. The research of microstructure, porosity, adhesion, microhardness and modulus of elasticity of the coatings were carried out. In the final master work numerical simulation of thermal spray coatings are described and results are presented graphically. The experimental and numerical results of thermal spray coatings were analysed and conclusions were given. Structure: introduction, literature review and analysis, experimental research of Ni and Co based plasma spray coating properties and microstructure, numerical simulation of thermal spray coating, results of the studies, conclusions, references.

Submitted by Automa??o e Estat?stica (sst@bczm.ufrn.br) on 2016-02-29T21:50:23Z No. of bitstreams: 1 JoseAntonioBarrosLealReisAlves_TESE.pdf: 5550413 bytes, checksum: 4c1d98761f0c020539c60eca7d324bf6 (MD5) / Approved for entry into archive by Arlan Eloi Leite Silva (eloihistoriador@yahoo.com.br) on 2016-03-01T21:55:58Z (GMT) No. of bitstreams: 1 JoseAntonioBarrosLealReisAlves_TESE.pdf: 5550413 bytes, checksum: 4c1d98761f0c020539c60eca7d324bf6 (MD5) / Made available in DSpace on 2016-03-01T21:55:58Z (GMT). No. of bitstreams: 1 JoseAntonioBarrosLealReisAlves_TESE.pdf: 5550413 bytes, checksum: 4c1d98761f0c020539c60eca7d324bf6 (MD5) Previous issue date: 2014-06-09 / O aumento da demanda energ?tica est? sendo atendida em grande parte por reservas de combust?veis f?sseis, que emitem CO2, SOx e v?rios outros gases poluentes. Cresce tamb?m a busca por combust?veis que emitam menos poluentes e que possuam a mesma efici?ncia energ?tica. Neste contexto, o hidrog?nio (H2) vem sendo cada vez mais reconhecido como um potencial carreador de energia para um futuro pr?ximo. Isso ocorre porque o H2 pode ser obtido por diversas rotas e tem uma vasta ?rea de aplica??o, al?m de possuir queima limpa, gerando apenas H2O como produto da queima, e a maior densidade de energia por unidade de massa. O processo de reforma com recircula??o qu?mica (RRQ) vem sendo bastante investigado nos ?ltimos anos, pois ? poss?vel regenerar o carreador de oxig?nio por meio da aplica??o de ciclos de redu??o e oxida??o. Este trabalho tem como objetivo geral desenvolver carreadores de oxig?nio a base de n?quel e cobalto para estudar a reatividade em processo de reforma com recircula??o qu?mica. Os carreadores de oxig?nio foram preparados por tr?s m?todos diferentes: combust?o assistida por microondas, impregna??o por via ?mida e coprecipita??o. Todos os materiais sintetizados possuem a mesma quantidade em massa das fases ativas (60%m/m). Os 40%m/m restantes s?o de La2O3 (8%m/m), Al2O3 (30%m/m) e MgO (2%). Os carreadores de oxig?nio foram nomeados da seguinte forma: N ou C, n?quel ou cobalto, seguido do n?mero 3 ou 6, que significa 30 ou 60% de fase ativa na forma de ?xido e C, CI ou CP, que significa combust?o assistida por micro-ondas, combust?o assistida por micro-ondas seguida de impregna??o por via ?mida e co-precipita??o. Os carreadores de oxig?nio foram ent?o caracterizados atrav?s das t?cnicas de difra??o de raios X (DRX), ?rea espec?fica (BET), redu??o ? temperatura programada (RTP) e microscopia eletr?nica de varredura (MEV). Os resultados de caracteriza??o mostraram que os diferentes m?todos de s?ntese levaram ? obten??o de diferentes estruturas e morfologias. Os testes de redu??o/oxida??o utilizando CH4 como redutor e ar sint?tico como oxidante foram realizados com os carreadores de oxig?nio N6C e C6C, N6CI e C6CI e N6CP e C6CP. Os testes revelaram diferentes comportamentos e que estes dependem do tipo de fase ativa bem como do tipo de s?ntese. O carreador de oxig?nio N6C foi o que produziu mais H2, ao passo que o carreador de oxig?nio C6CI foi o que produziu mais CO2 e H2O, sem ocorr?ncia da forma??o de coque. / Increasing energy demand is being met largely by fossil fuel reserves, which emit CO2, SOx gases and various other pollutants. So does the search for fuels that emit fewer pollutants and have the same energy efficiency. In this context, hydrogen (H2) has been increasingly recognized as a potential carrier of energy for the near future. This is because the H2 can be obtained by different routes and has a wide application area , in addition to having clean burning, generating only H2O as a product of combustion , and higher energy density per unit mass . The Chemical Looping Reforming process (CLR) has been extensively investigated in recent years, it is possible to regenerate the catalyst by applying cycles of reduction and oxidation. This work has as main objective to develop catalysts based on nickel and cobalt to study the reactivity of reform with chemical recycling process. The catalysts were prepared by three different methods: combustion assisted by microwave, wet impregnation and co-precipitation. All catalysts synthesized have the same amount by weight of the active phases (60% w / w). The other 40 % m/m consists in La2O3 (8% w / w), Al2O3 (30% w / w) and MgO (2%). Oxygen carriers have been named as follows: N or C, nickel or cobalt, followed by the number 3 or 6, meaning 30 to 60% of active phase in the oxide form and C, CI or CP, which means self-combustion assisted by microwave, self-combustion assisted by microwave followed by wet impregnation and co-precipitation. The oxygen carriers were then characterized by the techniques of X-ray diffraction (XRD), surface area (BET), temperature programmed reduction (TPR) and scanning electron microscopy (SEM). The characterization results showed that the different synthesis methods have led to obtaining different morphologies and structures. Redox tests using CH4 as reducing agent and sintetic air as oxidant agent was done with N6C and C6C, N6CI and C6CI and N6CP and C6CP oxygen carriers. The tests revealed different behaviors, depending on active phase and on synthesis procedure. N6C oxygen carrier produced high levels of H2. The C6CI oxygen carrier produced CO2 and H2O without carbon deposits.

Ce travail est consacré à la conception, à la synthèse et à l’étude de catalyseurs d’oxydation à base de métaux 3d en association avec des ligands non-innocents. Tout d’abord, le développement de complexes dérivés de deux ligands rédox-actifs tétra-azotés originaux (motifs o-phénylènediamine, aniline et dipyrrine) a été étudié. Plusieurs espèces dans différents états d’oxydation ont été préparées. L’élucidation de leurs structures électroniques a été réalisée par des techniques complémentaires (diffraction des rayons X, électrochimie, spectroscopies UV-Vis-NIR, EPR et Mössbauer). Un complexe de fer biradicalaire basé sur le ligand bis(2-aminophényl)-o-phénylènediamine a été synthétisé. Parallèlement, une architecture innovante bis(2-aminophényl)dipyrrine a été développée. En réaction avec du nickel, du cuivre et du cobalt, elle a conduit à trois complexes isostructuraux présentant un caractère radicalaire anilinyle-dipyrrinyle jamais mis en évidence auparavant. La complexation de cette dipyrrine au manganèse a formé un singulier complexe dinucléaire radicalaire avec une valence mixte inhabituellement localisée sur le ligand.Dans un second temps, les complexes de fer, de cuivre et de manganèse ont été évalués dans des applications d’oxydation. L’étude de la réactivité du biradicalaire de fer a entraîné l’observation d’une espèce à haute valence en spectroscopie Mössbauer. D’autre part, le complexe de cuivre a montré une activité en oxydation d’un alcool. Enfin, une activité en catalyse d’oxygénation aérobie a été identifiée avec le complexe dinucléaire radicalaire de manganèse. / This work is devoted to the design, the synthesis and the study of oxidation catalysts, based on 3d metals and non-innocent ligands. First, the development of complexes derived from two unprecedented tetra-nitrogenated redox-active ligands (o-phenylenediamine, aniline and dipyrrin motifs) has been investigated. A number of species at various oxidation states has been prepared. The elucidation of their electronic structures was performed by complementary techniques (X-Ray diffraction, electrochemistry, UV-Vis-NIR, EPR and Mössbauer spectroscopy). A biradical iron complex based on the bis(2-aminophenyl)-o-phenylenediamine ligand was synthesized. In parallel, an innovative bis(2-aminophenyl)dipyrrin architecture was developed. Its reactions with nickel, copper and cobalt led to three isostructural complexes, showing an unprecedented anilinyl-dipyrrinyl radical character. The complexation of the dipyrrin to manganese afforded a unique dinuclear radical complex with a rare ligand-based mixed valence.In a second phase, iron, copper and manganese complexes were assessed in oxidation applications. The reactivity study of the biradical iron resulted in the observation of a high-valent species thanks to Mössbauer spectroscopy. On the other hand, the copper complex has shown an activity in the oxidation of an alcohol. Finally, a catalytic aerobic activity in oxygenation catalysis was identified with the dinuclear manganese radical complex.

<p style="text-align: justify; ">Reactions of 3,5-dimethylpyrazole-1-carboxamidinium&nbsp;nitrate (dpca∙HNO3) and 4-acetyl-3-amino-5-methylpyrazole (aamp) with transition metals under different reaction conditions are presented. The template reaction of aamp with triethyl orthoformate (teof) in the presence of metal ion is described. Besides, condensation of aamp with thiosemicarbazide (tsc) and the coordination of its product to copper(II) ion is also described. Twelve new complex compounds are synthesized and fully characterized. The characterization of two other, already known complexes is significantly enriched. The influence of HSAB interactions between the metal ions and ligators on the structures of obtained compounds is studied. The influence of the reaction conditions on the composition, structure and quality of crystals obtained in the reactions is investigated. Compounds are characterized by structural&nbsp;analysis, elemental analysis, molar conductivity data, infrared spectrometry and thermal analysis. Some selected complexes are characterized by UV-Vis spectra, magnetic measurements and biological activity tests, too.</p> / <p> Reactions of 3,5-dimethylpyrazole-1-carboxamidinium&nbsp;nitrate (dpca∙HNO3) and 4-acetyl-3-amino-5-methylpyrazole (aamp) with transition metals under different reaction conditions are presented. The template reaction of aamp with triethyl orthoformate (teof) in the presence of metal ion is described. Besides, condensation of aamp with thiosemicarbazide (tsc) and the coordination of its product to copper(II) ion is also described. Twelve new complex compounds are synthesized and fully characterized. The characterization of two other, already known complexes is significantly enriched. The influence of HSAB interactions between the metal ions and ligators on the structures of obtained compounds is studied. The influence of the reaction conditions on the composition, structure and quality of crystals obtained in the reactions is investigated. Compounds are characterized by structural<br /> analysis, elemental analysis, molar conductivity data, infrared spectrometry and thermal analysis. Some selected complexes are characterized by UV-Vis spectra, magnetic measurements and biological activity tests, too</p>

In der vorliegenden Arbeit werden zwei Enzymsysteme – Ni-haltige Kohlenmonoxid-Dehydrogenase (CODH) und [NiFe]-haltige Hydrogenase – strukturell untersucht. Im 1. Teil werden die Untersuchungen des ACDS-Komplexes aus A. fulgidus mittels Transmissionselektronenmikroskopie (Negativkontrastierung und der Kryo-Einbettung) geschildert. Die 3D-Rekonstruktion mit einer Auflösung von 29 Å wird de novo ermittelt und drei mögliche Positionen für die CODH-Untereinheit vorgeschlagen. Im 2. Teil wird die Röntgenkristallstrukturanalyse der CODH-Untereinheit des ACDS Komplexes aus A. fulgidus geschildert. Das Protein besteht aus α- und ε-Untereinheiten, die zusammen eine α2ε2-Stöchiometrie bilden (Afα2ε). Während die Gesamtstruktur von Afα2ε2 jener von M. barkeri (Mbα2ε2) ähnelt, führt der Austausch der koordinierenden Cys zu Asp und Glu zu einer Deletion des verbrückenden FeS-Zentrums. Die Rolle der ε-Untereinheit wird durch kinetische Studien untersucht. Die CO-abhängige FAD-Reduktionsaktivität von Afα2ε2 folgt einer Michaelis-Menten Kinetik. Die Mbα2ε2 hat ein ähnliches Kinetikverhalten. Im Gegensatz dazu weist die CODH-II von C. hydrogenoformans, die keine ε-Untereinheit hat, eine lineare Abhängigkeit der CO-abhängigen FAD-Reduktionsaktivität von Flavin auf. Diese Beobachtungen sind im Einklang mit der Annahme, dass die ε-Untereinheit ein Gerüst für die Flavinbindung bereitstellt. Der 3. Teil ist der F420-reduzierenden Hydrogenase aus M. barkeri (MbFRH) gewidmet. Die Struktur von MbFRH wird mittels Röntgenkristallographie bestimmt und ergibt eine dodekamerische Anordnung von ca. 1.2 MDa. Zusammen mit der etablierten Elektronenübertragungskette, beobachtet in FRH aus M. marburgensis, wird in MbFRH auch ein [2Fe2S]-Cluster und eine Fe-Stelle detektiert. Schließlich führen die schwingungsspektroskopischen Analysen zusammen mit der Röntgenkristallographie zu dem Schluss, dass MbFRH in einem bisher strukturell nicht charakterisierten, katalytisch aktiven Nia-S Zustand isoliert wird. / In this work, we structurally characterize two metal-based enzyme systems from archaea: Ni-containing CO dehydrogenase (CODH) and [NiFe] containing hydrogenase. In the first chapter we investigate, using transmission electron microscopy, the ACDS complex from A. fulgidus (AfACDS). The purified ACDS complex can be visualized as an intact globular protein particle by negative stain and vitrification techniques. The 3D reconstruction is determined de novo to 29 Å-resolution by single-particle analysis. We suggest three possible positions for the CODH subunit within ACDS by rigid-body fitting. In the second chapter we determine the X-ray crystal structure of the CODH subunit. The 220 kDa protein is composed of α- and ε-subunits that form a heterodimer with (α2ε2) stoichiometry (Afα2ε2). While the overall structure of Afα2ε2 resembles the previously reported structure of the α2ε2-subunit from M. barkeri (Mbα2ε2), the naturally-occurring exchange of the Cys to Asp and Glu results in a depletion of the bridging iron-sulfur cluster. The role of the ε-subunit is investigated by kinetics studies. CO-dependent FAD reduction activity of Afα2ε2 exhibits Michaelis-Menten type kinetics. The same kinetic type is demonstrated for the Mbα2ε2-subunit. In contrast, the ε-subunit lacking CODH-II from C. hydrogenoformans shows linear dependency between CO-dependent FAD reduction activity and flavin concentration. The data suggests that the ε-subunit provides a scaffold for the flavin binding. In the third chapter we study the F420-reducing hydrogenase from M. barkeri (MbFRH). Its structure is solved by X-ray crystallography, revealing a dodecameric arrangement of 1.2 MDa. Along with the established ET chain observed in FRH from M. marburgensis, one solvent-exposed [2Fe2S] cluster and an additional Fe metal site are detected. The combined approach of X-ray crystallography and vibrational spectroscopy reveals that MbFRH is isolated in the previously structurally uncharacterized Nia-S state.