Dissertations / Theses: 'Rotating Electrode'

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Hansen, James Christopher. "Rotating Electrode Pulse Gas Metal Arc Welding for Improved Aluminum Shipbuilding Quality." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1606991932450895.

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2

Zhang, Fen. "Applications of Rotating Ring-Disc Electrode in CO2 Electrochemical Reduction in Aqueous Media." The Ohio State University, 2020. http://rave.ohiolink.edu/etdc/view?acc_num=osu1577812269219211.

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3

Tran, Van Nhat Anh. "MONITORING OF SULFUR - CONTAING ADDITIVES IN COPPER ELECTRODEPOSITION BY ROTATING RING - DISK ELECTRODE AND COPPER ELECTRODEPOSITION FOR HYBRID BONDING." Doctoral thesis, Kyoto University, 2021. http://hdl.handle.net/2433/264677.

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京都大学
新制・課程博士
博士(エネルギー科学)
甲第23396号
エネ博第423号
新制||エネ||80(附属図書館)
京都大学大学院エネルギー科学研究科エネルギー応用科学専攻
(主査)教授平藤哲司, 教授土井俊哉, 准教授三宅正男
学位規則第4条第1項該当
Doctor of Energy Science
Kyoto University
DGAM

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4

Lukus, Peter Alan. "Electrochemical investigations of dopamine using rotating disk electrode voltammetry| Study of release and reuptake kinetics and inhibition of the neuronal dopamine transporter." Thesis, Washington State University, 2014. http://pqdtopen.proquest.com/#viewpdf?dispub=3611281.

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The dopamine transporter (DAT) is the neuronal transporter for the neurotransmitter dopamine (DA). The use of rotating disk electrode voltammetry (RDEV) is a technique used to study transport of DA by DAT. This can be done in normal tissue, as well as tissue samples that have received pharmacological manipulation, such as the addition of the DAT uptake inhibitors cocaine and methamphetamine (METH). In Chapter Two, the rates of exogenous uptake of DA via DAT in rat striatal tissue is studied. Studies are conducted in whole striatal samples, as well as in anterior and posterior sections of striatal tissue to assess variability in DAT function as a function of DA concentration. It is found that the kinetic rates of transport in exogenous tissue vary between anterior and posterior sections, as does the rate of reuptake after stimulation of DA release via KCl addition. Release and reuptake rates of anterior and posterior striatum vary, suggesting that DAT is not kinetically regulated by available local DA concentrations.

Chapter Three details studies on the differences of release and subsequent reuptake of DA via DAT in response to METH and amphetamine (AMPH) stimulation. A comparison of the amount of DA released, as well as release and reuptake rates, is presented. Findings suggest that AMPH stimulation causes a similar concentration of DA to be released in comparison to METH, while METH caused greater reduction of DA uptake. AMPH salts such as Ritalin are common medications for children with ADHD, and alternative therapeutic measures for ADHD management are discussed.

Chapter Four presents analysis of DAT function in hooded rats afflicted with Parkinson's symptoms. Transport rates of exogenous DA uptake, as well as stimulated DA release and subsequent reuptake, are measured. DAT kinetic function is shown to be retained in Parkinson's rats, suggesting that the transporter is unaffected by the disease in the striatal tissue.

Chapter Five presents a brief overview of the work discussed, along with conclusions and future work.

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5

Liao, Anna. "Part A. Development, evaluation and application of a rotating mercury pool electrode based on the electrochemical centrifugal analyzer ; Part B. Development and application of a microcarbon fiber electrode... ; Part C. Development and application... /." The Ohio State University, 1985. http://rave.ohiolink.edu/etdc/view?acc_num=osu148725825402032.

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6

Morana, Roberto. "The influence of particle type and process conditions on electrodeposited composite coatings." Thesis, Loughborough University, 2006. https://dspace.lboro.ac.uk/2134/8045.

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Composite materials are usually multi-phase materials, made up from two or more phases, which are combined to provide properties that the individual constituents cannot. This technology represents an economical way to improve product performances avoiding the use of expensive materials. Composite materials can be obtained as films by means of the electrolysis of electroplating solutions in which micrometre- or submicrometre-size particles are suspended: variable amounts of these particles become incorporated in the electrochemically produced solid phase, to which they impart enhanced properties. The main aims of the present work contributing to this thesis are the study of different parameters influencing the electroco-deposition process in order to promote and improve the applicability of such a technology in the high speed electroplating industry. Following a comprehensive review on the electroco-deposition of composite coatings, the phenomena have been analysed moving from a microscopic point of view i. e. the role of the metal ions present in the electrolyte and adsorption on the inert particles and their interactions with the growing metal layer, to a macroscopic point of view i. e. the electrolyte agitation, its influence on particle motion and all the issues related to the presence of particles in an electrolyte during electroplating. In particular the inert particle influence in terms of geometry, dimension and chemical nature (spherical polystyrene particles vs. irregular alumina particles with different dimensions), the metal matrix influence (nickel, copper and zinc), the influence of electrolyte agitation (using a Rotating Cylinder Electrode cell system) and the influence of the coating thickness on particle content in the final coating, using different deposition times, have been examined. The importance of the particle shape has been highlighted showing how incorporating irregular geometries gave higher particle incorporation densities than regular geometries. The influence of the substrate finishing in terms of imperfections has been related to the particle incorporation rate showing how small surface imperfections enhanced the incorporation of particles. Different hydrodynamic regimes have been analysed resulting three different regimes being discerned: laminar, transitional and turbulent. The consequence, in terms of particle incorporation levels, has been found showing how the amount of particles in the coating changed from one regime to another. Different rate-determining steps were related to the hydrodynamics: when the regime is laminar, particles were incorporated as agglomerates and the process was under particle transfer control, whilst in the turbulent zone, the rate determining step was the velocity of reduction of the ions adsorbed on the particle surface.

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Zeszut, Ronald Anthony Jr. "Effects of Transport and Additives on Electroless Copper Plating." Case Western Reserve University School of Graduate Studies / OhioLINK, 2017. http://rave.ohiolink.edu/etdc/view?acc_num=case1497271315649528.

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8

Schlögl, Katrin [Verfasser], Matthias [Akademischer Betreuer] Arenz, Ulrich K. [Akademischer Betreuer] Heiz, and Kai-Olaf [Akademischer Betreuer] Hinrichsen. "Identical location transmission electron microscopy in combination with rotating disc electrode measurements : the activity of fuel cell catalysts and their degradation / Katrin Schlögl. Gutachter: Matthias Arenz ; Ulrich K. Heiz ; Kai-Olaf Hinrichsen. Betreuer: Matthias Arenz." München : Universitätsbibliothek der TU München, 2011. http://d-nb.info/1014330203/34.

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9

Lima, Thaís Guimarães de. "Eletrodeposição de revestimentos funcionais compósitos Cu/partículas de óxidos de alumínio." Universidade do Estado do Rio de Janeiro, 2013. http://www.bdtd.uerj.br/tde_busca/arquivo.php?codArquivo=9523.

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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Revestimentos funcionais compósitos são um atrativo tecnológico crescente, pois possibilitam a combinação de materiais metálicos, poliméricos ou cerâmicos, resultando em propriedades superiores as dos materiais individuais, sendo por este motivo, largamente aplicados na engenharia de materiais. Na presente dissertação, foram produzidos revestimentos compósitos por eletrodeposição através da codeposição de uma matriz metálica de cobre e de partículas de óxidos de alumínio incorporadas (g - Al2O3 ou AlO(OH)), sobre substratos de aço carbono, a partir de diferentes banhos eletrolíticos. Três etapas foram efetuadas, na primeira realizou-se o estudo da influência do modo de agitação e da presença ou não de ligantes (citrato de sódio 1,00 mol/L) nos teores de cobre e alumina nos revestimentos produzidos. Em seguida foi avaliada a ação de complexantes (citrato de sódio 1,00 mol/L e pirofosfato de potássio 0,90 mol/L) usando polarização potenciodinâmica e voltametria cíclica, em conjunto com microbalança eletroquímica de cristal de quartzo (EQCM) e a posterior produção de revestimentos compósitos a partir de banhos contendo CuSO4 0,02 mol/L + pirofosfato de potássio 0,90 mol/L + 20 g/L de alumina, variando a densidade de corrente aplicada (I), a velocidade de agitação do eletrodo rotatório (A) e o do tempo de agitação prévia (t). Por fim, na terceira etapa, fez-se a substituição de alumina por Boehmita e a produção dos revestimentos a partir de banhos contendo CuSO4 0,02 mol/L + pirofosfato de potássio 0,90 mol/L + 20 g/L de Boehmita, empregando um planejamento composto central, em que os parâmetros citados também foram variados. Os resultados mostraram que a presença de um ligante e a agitação prévia e continuada do eletrólito durante o experimento foram fundamentais para a produção dos revestimentos compósitos. Ensaios de EQCM mostraram que o citrato se adsorveu na superfície do eletrodo de ouro, diferentemente do pirofosfato. Os teores de Boehmita e cobre nos revestimentos produzidos, assim como a morfologia, resistência de polarização e densidade de corrente de corrosão dos revestimentos foram influenciados pelos parâmetros avaliados.
Functional coatings composites are an increasing technologic attractive, as they allow the combination of metallic, polymeric or ceramic materials resulting in properties superior than those of the individual materials. They are, therefore, widely used in engineering materials. In this dissertation, composite coatings were produced by electrodeposition through co-deposition of a copper metal matrix and particulate aluminum oxides embedded (g - Al2O3 or AlO (OH)) on carbon steel substrates from different electrolytic baths. Three steps were taken: first the influence of the stirring mode and the presence or absence of ligands (sodium citrate 1.00 mol/L) in the amount of copper and alumina in the produced coatings were studied. After it, was evaluated the action of complexing agents (Sodium citrate 1.00 mol/L and potassium pyrophosphate 0.90 mol/L) using potentiodynamic polarization and cyclic voltammetry together with electrochemical microbalance quartz crystal (EQCM), and further producing composite coatings from baths containing CuSO4 0.02 mol/L potassium pyrophosphate + 0.90 mol/L + 20 g/L of alumina, varying the applied current density (I), the stirring speed of the rotating electrode (A) and the stirring time prior to electrodeposition (t). Finally in the last step was performed the substitution of alumina by bohemite and production of coatings from baths containing CuSO4 0.02 mol/L potassium pyrophosphate + 0.90 mol/L + 20 g/L bohemite, employing a central composite design, in which these parameters were also varied. The results showed that the presence of a ligand and the electrolyte stirring prior and during the experiment were critical to the production of composite coatings. EQCM tests showed that the citrate is adsorbed on the surface of the gold electrode, unlike pyrophosphate. The results showed that the contents of boehmite and copper in the coatings produced, as well as the morphology, polarization resistance and corrosion current density of the coatings were influenced by the evaluated parameters

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10

Benzekri, Najoua. "Contribution au developpement de l'electrode disque-anneau en courant alternatif : applications aux mecanismes de dissolution et passivation anodique." Paris 6, 1988. http://www.theses.fr/1988PA066069.

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Developpement de la methode de l'electrode tournante a disque anneau en regime de perturbation sinusoidale du disque. Etude theorique de la cinetique des reactions electrodes. Faisabilite de la technique pour differents processus: corrosion dissolution active, passivation en milieu acide

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11

Mohammed, Nor Azmi. "The Effect of Turbulent Flow on Corrosion of Mild Steel in High Partial CO₂ Environments." Ohio University / OhioLINK, 2013. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1363706400.

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12

Ryabova, Anna. "Électrocatalyse de la réduction de l'oxygène et du peroxyde d'hydrogène sur les oxydes de manganèse." Thesis, Strasbourg, 2018. http://www.theses.fr/2018STRAF011/document.

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Les oxydes de manganèse présentent un grand intérêt en raison de leur activité catalytique pour l'ORR (la réaction de réduction de l’oxygène) en milieu alcalin et peuvent être utilisés comme matériaux sans métaux nobles pour la cathode dans les piles à combustible. La présente thèse est consacrée à l’étude de l’activité d'oxydes de manganèse pour l’ORR. Il a été montré que Mn2O3 avec structure bixbyite a une meilleure activité catalytique vers l'ORR en milieu alcalin que les autres oxydes de manganèse étudiés. L'activité spécifique de Mn2O3 est seulement 4 fois inférieure à celle de Pt à une surtension de 0.3 V (ERH). Le lien entre la structure des oxydes de Mn et l'activité ORR est identifié: l'activité spécifique augmente exponentiellement avec le potentiel du couple redox Mn(III)/Mn(IV) de surface. Pour assurer l'activité électrocatalytique élevée de Mn2O3, il est nécessaire d'ajouter du carbone à la composition d'électrode, ainsi que de garder un potentiel supérieur à 0.7 V (ERH)
Manganese oxides are of great interest due to their catalytic activity towards the ORR (the oxygen reduction reaction) in alkaline media and can be used as noble metal-free materials for the cathode in liquid and polymer electrolyte alkaline fuel cells. The present thesis is devoted to the investigation of the ORR activity of manganese oxides. It was shown that Mn2O3 with bixbyite structure has a better catalytic activity toward the ORR in alkaline media than other investigated manganese oxide, the surface activity of Mn2O3 is only 4 times lower than that of Pt at an overvoltage of 0.3 V (RHE). The link between the structure of Mn oxides and the ORR activity is found: the specific ORR activity exponentially increases with the potential of the surface Mn(III)/Mn(IV) red-ox couple. To ensure the high electrocatalytic activity of Mn2O3, it is necessary to add carbon to the electrode composition, as well as to keep potential above 0.7 V (RHE)

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13

Campos, Othon Souto. "Estudo MecanÃstico da EletrodeposiÃÃo de CÃdmio em Meio de Sulfato Ãcido." Universidade Federal do CearÃ, 2011. http://www.teses.ufc.br/tde_busca/arquivo.php?codArquivo=6260.

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Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
Este trabalho descreve uma proposiÃÃo mecanÃstica para a deposiÃÃo de cÃdmio em meio de sulfato Ãcido sobre substrato de platina utilizando tÃcnicas eletroquÃmicas. Os estudos de eletrodeposiÃÃo de cÃdmio foram feitas em meio de sulfato de sÃdio 1 mol Lâ1 contendo 10â2 mol Lâ1 de sulfato de cÃdmio, em que o pH das soluÃÃes foi ajustado com Ãcido sulfÃrico PA. O intervalo de pH das soluÃÃes de trabalho foi variado entre 1 e 3. Em todos os meios estudados, as curvas de polarizaÃÃo potenciostÃtica mostraram a formaÃÃo de um patamar difusional que obedece a equaÃÃo de Levich. Os estudos de pH local revelaram a influÃncia do equilÃbrio Ãcidoâbase do Ãon bissulfato com formaÃÃo de compostos de coordenaÃÃo Cd(HSO4)+ no eletrodo de platina. PropÃe-se que o Ãon cÃdmio, associado ao equilÃbrio Ãcidoâbase do Ãon bissulfato, deposita como bissulfato de cÃdmio numa etapa irreversÃvel, e seguida pela deposiÃÃo de cÃdmio metÃlico reversÃvel com a saÃda do Ãon bissulfato, sendo esta Ãltima etapa mais lenta que a primeira. Desse modo, foi calculado um modelo matemÃtico para o mecanismo proposto, sendo realizados estudos qualitativos em relaÃÃo ao comportamento da curva de polarizaÃÃo e do espectro de impedÃncia eletroquÃmica
This work describes a mechanistical proposition for cadmium electrodeposition in acid sulfate medium on platinum substrate using electrochemical techniques. The cadmium electrodeposition studies were carried in sodium sulfate 1 mol Lâ1 medium containing cadmium sulfate 10â2 mol Lâ1, which the pH of the solutions were adjusted with analytical grade sulfuric acid. The pH interval of the work solutions were ranged between 1 and 3. In all studied medium, the potentiostatic polarization curves showed a diffusional plateau which obeys the Levich equation. The interfacial pH studies showed the influence of acidâbase equilibrium of bisulfate ion with the formation of a coordination compound Cd(HSO4)+ in platinum electrode. It is proposed that the cadmium ion associated in acidâbase equilibrium of bisulfate ion, deposits as cadmium bisulfate at an irreversible step, and followed by a reversible metallic deposition of cadmium with the leaving of bisulfate ion, and this step is slower than the first one. Then, a mathematical model was calculated for the mechanism proposed, and qualitative studies were carried regarding to the polarization curve and electrochemical impedance spectroscopy behavior

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14

Samuila, Adrian-Paun. "Charge et trajectoires des particules dans les séparateurs électrostatiques." Université Joseph Fourier (Grenoble), 1997. http://www.theses.fr/1997GRE10090.

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L'objectif de ce travail a ete d'ameliorer la comprehension des phenomenes physiques mis en jeu dans les separateurs electrostatiques a electrode cylindrique tournante. Les etudes ont porte essentiellement sur les mecanismes de charge des particules et sur les facteurs qui influencent les trajectoires de celles-ci dans le champ electrique de ces installations. Une methode originale, basee sur l'analyse numerique du champ electrique, est proposee pour le calcul de la charge acquise en champ ionise par des particules isolantes de forme et de dimensions variees posees sur une electrode ou a proximite de celle-ci. Les predictions theoriques sont confirmees par des mesures effectuees sur une installation experimentale qui modelise les conditions de charge specifiques aux separateurs electrostatiques et qui permet une evaluation de l'efficacite de divers types d'electrodes ionisantes. Des experiences realisees avec un autre dispositif montrent que cette efficacite est liee a l'intensite du courant genere par l'electrode et a l'uniformite de sa distribution a la surface de l'electrode collectrice. La these ameliore aussi le modele numerique utilise pour l'etude du comportement des particules conductrices en champ harmonique ou ionise et pour le calcul de leurs trajectoires dans les separateurs electrostatiques a electrode cylindrique tournante. Le modele a ete valide par des experiences realisees dans diverses configurations d'electrodes. Les resultats de ces etudes contribuent au developpement de quelques applications industrielles. La these montre la possibilite d'utiliser un separateur electrostatique a zone etendue de champ ionise pour la recuperation du laiton des dechets industriels. Diverses solutions sont analysees pour recycler les materiaux isolants et les metaux provenant des dechets de cables electriques. Enfin, une technologie nouvelle est proposee pour la purification des concentres de mica.

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15

Campos, Othon Souto. "Estudo Mecanístico da Eletrodeposição de Cádmio em Meio de Sulfato Ácido." reponame:Repositório Institucional da UFC, 2011. http://www.repositorio.ufc.br/handle/riufc/15608.

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CAMPOS, O. S. Estudo Mecanístico da Eletrodeposição de Cádmio em Meio de Sulfato Ácido. 2011. 45 f. Dissertação (Mestrado em Química) - Centro de Ciências, Universidade Federal do Ceará, Fortaleza, 2011.
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This work describes a mechanistical proposition for cadmium electrodeposition in acid sulfate medium on platinum substrate using electrochemical techniques. The cadmium electrodeposition studies were carried in sodium sulfate 1 mol L–1 medium containing cadmium sulfate 10–2 mol L–1, which the pH of the solutions were adjusted with analytical grade sulfuric acid. The pH interval of the work solutions were ranged between 1 and 3. In all studied medium, the potentiostatic polarization curves showed a diffusional plateau which obeys the Levich equation. The interfacial pH studies showed the influence of acid–base equilibrium of bisulfate ion with the formation of a coordination compound Cd(HSO4)+ in platinum electrode. It is proposed that the cadmium ion associated in acid–base equilibrium of bisulfate ion, deposits as cadmium bisulfate at an irreversible step, and followed by a reversible metallic deposition of cadmium with the leaving of bisulfate ion, and this step is slower than the first one. Then, a mathematical model was calculated for the mechanism proposed, and qualitative studies were carried regarding to the polarization curve and electrochemical impedance spectroscopy behavior
Este trabalho descreve uma proposição mecanística para a deposição de cádmio em meio de sulfato ácido sobre substrato de platina utilizando técnicas eletroquímicas. Os estudos de eletrodeposição de cádmio foram feitas em meio de sulfato de sódio 1 mol L–1 contendo 10–2 mol L–1 de sulfato de cádmio, em que o pH das soluções foi ajustado com ácido sulfúrico PA. O intervalo de pH das soluções de trabalho foi variado entre 1 e 3. Em todos os meios estudados, as curvas de polarização potenciostática mostraram a formação de um patamar difusional que obedece a equação de Levich. Os estudos de pH local revelaram a influência do equilíbrio ácido–base do íon bissulfato com formação de compostos de coordenação Cd(HSO4)+ no eletrodo de platina. Propõe-se que o íon cádmio, associado ao equilíbrio ácido–base do íon bissulfato, deposita como bissulfato de cádmio numa etapa irreversível, e seguida pela deposição de cádmio metálico reversível com a saída do íon bissulfato, sendo esta última etapa mais lenta que a primeira. Desse modo, foi calculado um modelo matemático para o mecanismo proposto, sendo realizados estudos qualitativos em relação ao comportamento da curva de polarização e do espectro de impedância eletroquímica

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Krarti, Mohamed Ali. "Contribution a l'etude de la passivite du fer et de sa rupture sur electrodes a disque et disque-anneau : facteurs electrochimiques et hydrodynamiques." Paris 7, 1988. http://www.theses.fr/1988PA077087.

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Influence du regime hydrodynamique de la solution corrosive sur la surface d'un metal passif (fer) sensible a la corrosion par piqure. Etude a l'aide de techniques d'electrodes tournantes (electrode disque, electrode disque-anneau)

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17

Copham, Piers Martin. "Rotating electrodes in molten salt electrowinning." Thesis, University of Cambridge, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.330202.

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Prieto, Yespica Wolfgang José. "Etude comparative du comportement électrochimique des alliages d'aluminium 2024 T351 et 7075 T7351 en milieu neutre de sulfate de sodium." Thesis, Toulouse, INPT, 2012. http://www.theses.fr/2012INPT0054/document.

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Ce travail concerne l'étude du comportement vis-à-vis de la corrosion de deux alliage d'aluminium : l'alliage 2024 (AA 2024 T351) et l'alliage 7075 (AA7075 T7351) et de l'aluminium pur, utilisé comme référence, dans une solution de Na2SO4 0,1 M à l'aide de mesures électrochimiques (courbes de polarisation, courbes de Levich et spectroscopie d'impédance) avec des électrodes à disque tournant. Comparativement aux travaux de la littérature, des données quantitatives sur les processus anodique et cathodique qui se produisent sur les deux alliages ont été obtenues. La première partie de la thèse est consacrée à la caractérisation microstructurale des deux alliages : taille, composition chimique des précipités et fraction surfacique occupée par les différentes phases. La seconde partie présente les résultats d'impédance obtenus au potentiel de corrosion pour différents temps d'immersion et différentes vitesses de rotation. A ce potentiel, le comportement des matériaux est essentiellement contrôlé par le film passif. Les diagrammes d'impédance présentent une dispersion en fréquence, exprimée en termes de « constant phase element (CPE) ». Ce comportement a été analysé à l'aide d'un modèle physique qui permet de montrer une distribution de résistivité dans l'épaisseur des films d'oxyde. Dans la dernière partie, une attention particulière a été portée à l'analyse de la réaction cathodique à la surface des deux alliages qui est à l'origine de leur dégradation importante. La réduction de l'oxygène se produit principalement sur les particules intermétalliques. De façon surprenante, la densité de courant cathodique est nettement plus faible pour l'alliage 7075 qui présente une plus grande surface couverte par les particules. Il a été montré que pour l'alliage 2024, la réaction cathodique est contrôlée par le transport de matière par diffusion convective sur de petites électrodes alors que pour l'alliage AA 7075, la majeure partie des particules, de très petite taille, se comporte comme des microélectrodes pour lesquelles le courant est fixé par la diffusion sphérique, indépendante de la convection
This work concerns the study of behavior the corrosion of two aluminum alloy: the alloy 2024 (AA 2024 T351) and 7075 (AA7075 T7351) and pure aluminum, used as reference, in a solution of 0.1 M Na2SO4 using electrochemical measurements (polarization curves, curves Levich and impedance spectroscopy) with rotating disk electrodes. Compared to published studies, quantitative data on the anodic and cathodic processes occurring on the two alloys were obtained. The first part of the thesis is devoted to the microstructural characterization of two alloys: size, chemical composition of precipitates and surface fraction occupied by the different phases. The second part presents the results of impedance obtained at the corrosion potential for different immersion times and different speeds. At this potential, the behavior of materials is mainly controlled by the passive film. The impedance diagrams exhibit a frequency dispersion, expressed in terms of "constant stage element (CPE)." This behavior was analyzed using a physical model which allows to show a distribution of resistivity in the thickness of oxide films. In the last part, special attention was paid to the analysis of the cathodic reaction on the surface of the two alloys that is causing their degradation. The oxygen reduction occurs mainly on the intermetallic particles. Surprisingly, the cathode current density is significantly lower for the alloy 7075 which has a greater surface area covered by the particles. It was shown that for 2024 alloy, the cathodic reaction is controlled by material transport by convective diffusion of small electrodes, while for the alloy AA 7075, most of the particles, very small, behaves as microelectrodes for which the current is set by the spherical diffusion, independent of the convection

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Guymon, Clint Gordon. "MPSA Effects on Copper Electrodeposition: Understanding Molecular Behavior at the Electrochemical Interface." BYU ScholarsArchive, 2005. https://scholarsarchive.byu.edu/etd/333.

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In this work the structure of the electrochemical metal-liquid interface is determined through use of quantum mechanics, molecular simulation, and experiment. Herein are profiled the molecular dynamics details and results of solid-liquid interfaces at flat non-specific solid surfaces and copper metal electrodes. Ab initio quantum-mechanical calculations are reported and define the interatomic potentials in the simulations. Some of the quantum-mechanical calculations involve small copper clusters interacting with 3-mercaptopropanesulfonic acid (MPSA), sodium, chloride, bisulfate and cuprous ions. In connection with these I develop the electrode charge dynamics (ECD) routine to treat the charge mobility in a metal. ECD bridges the gap between small-scale metal-cluster ab initio calculations and large-scale simulations of metal surfaces of arbitrary geometry. As water is the most abundant surface species in aqueous systems, water determines much of the interfacial dynamics. In contrast to prior simulation work, simulations in this work show the presence of a dense 2D ice-like rhombus structure of water on the surface that is relatively impervious to perturbation by typical electrode charges. I also find that chloride ions are adsorbed at both positive and negative electrode potentials, in agreement with experimental findings. Including internal modes of vibration in the water model enhances the ion contact adsorption at the solid surface. In superconformal filling of copper chip interconnects, organic additives are used to bottom-up fill high-aspect ratio trenches or vias. I use molecular dynamics and rotating-disk-electrode experiments to provide insight into the function of MPSA, one such additive. It is concluded that the thiol head group of MPSA inhibits copper deposition by preferentially occupying the active surface sites. The sulfonate head group participates in binding the copper ions and facilitating their transfer to the surface. Chloride ions reduce the work function of the copper electrode, reduce the binding energy of MPSA to the copper surface, and attenuate the binding of copper ions to the sulfonate head group of MPSA.

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Tinani, Suraj P. "Techniques to Analyze Underdeposit Corrosion." Case Western Reserve University School of Graduate Studies / OhioLINK, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=case1272643724.

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21

Turkson, Abraham K. "Electro-ultrafiltration with rotating dynamic membranes." Thesis, McGill University, 1985. http://digitool.Library.McGill.CA:80/R/?func=dbin-jump-full&object_id=72036.

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In axial electrofiltration, a DC electric field is imposed between a rotating inner cylinder and a stationary outer cylinder giving rise to four mechanisms which act to minimize solute accumulation at the filter surface: turbulence, centrifugal force, electrophoresis and shear stress which removes solute aggregates.
Four dynamic membranes, Zr(IV) oxide, calcium oleate, poly-2-vinylpyridine and cadmium sulfide, were used to filter bovine serum albumin (BSA) in a disodium phosphate solution at pH = 8 and Prussian blue in distilled water. Prussian blue is a particle of 0.01(mu)m diameter with a zeta potential of -41mV while BSA is a macromolecule of 69,000 molecular weight, a Stokes-Einstein radius of 0.0038(mu)m and a zeta potential of -23.3mV at pH = 8. For BSA, the flux declined with time while the rejection increased. Filtrate fluxes increased with rotation rate and electric field and declined with concentration for both feeds. The flux declined beyond N = 2000rpm and was constant above C(,0) = 5.0wt%. For Prussian blue, the rejection was greater than 90% at all levels of E, N and C(,0). For BSA, the rejection increased with rotation rate and declined with concentration. The BSA rejection declined above N = 2000rpm and was constant beyond C(,0) = 0.5wt%.
A mathematical model was derived to predict the time variation of filtrate flux and a rejection model was used to predict the effect of surface concentration on BSA rejection.

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22

Gonzalez-Pena, Omar Israel. "Mass Transport Enhancement in Copper Electrodeposition due to Gas Co-Evolution." Case Western Reserve University School of Graduate Studies / OhioLINK, 2015. http://rave.ohiolink.edu/etdc/view?acc_num=case1439826379.

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23

Reade, Gavin W. "Mass transport to rotating reticulated vitreous carbon cylinder electrodes." Thesis, University of Portsmouth, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.339237.

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24

James, J. S. "Investigations of aqueous erosion-corrosion using rotating cylinder electrodes." Thesis, University of Manchester, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.504877.

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The use of rotating cylinder electrodes for the investigation of aqueous erosion-corrosion has determined that they are suited to the task with some minor modifications. The requirements that need to be met to ensure that true turbulence is produced within a cell to allow reproducible investigation of a range of erosion corrosion parameters have been elucidated. The cell must operate above Taylor numbers of 15000 and as such large annular gaps and higher temperatures are beneficial. Careful consideration of the conditions required needs to be made before designing a rotating cylinder for the study of erosion corrosion. The use of outer cylinder static electrodes has been determined, through mass transfer tests to be valid for a small annular gap of 5mm, allowing experiments to be set up in autoclaves that reproduce hostile process plant parameters. Fixed potential studies of the erosion corrosion of mild and chromium steel in deaerated 1M NaOH have determined that over the majority of the potential range studied there was no synergistic effect between corrosion and erosion. The erosion-corrosion rate was just the sum of the corrosion rate during erosion and the erosion rate in the absence of corrosion. Over a small potential range in the transpassive corrosion region of the chromium steel a negative synergistic effect was determined. In this region, the transpassive corrosion of chromium from the steel inhibits the erosion of the metal by impacting particles. The effect of particle size on total erosion-corrosion, and its separate erosion and corrosion components has revealed that for the same addition of particles by weight, the corrosion rate under erosion is independent of the particle size. However, the erosion produced is heavily dependent on the particle size, being approximately constant for large sizes and decreasing rapidly below 100jm. These findings have been corroborated by microscopy of the sample surfaces.

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Laidani, Abdelkader. "Influence des conditions hydrodynamiques sur la corrosion localisee (piqures et crevasses) de l'aluminium en milieu hydro-organique : effet des ions nitrate." Paris 6, 1988. http://www.theses.fr/1988PA066340.

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Etude sur disque tournant (en regime d'ecoulement laminaire) et en boucle de circulation (en regime d'ecoulement turbulent). Determination des parametres de transport et de frottement aux parois de la cellule de section rectangulaire utilisee dans le circuit de la boucle de circulation dans un ecoulement turbulent non etabli. Application des concepts hydrodynamiques a la corrosion de l'aluminium dans la solution hydroorganique de ph 7,6

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26

Low, C. T. John. "Rotating electrodes : the electrodeposition of tin and tin-copper alloys." Thesis, University of Southampton, 2007. https://eprints.soton.ac.uk/195955/.

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27

Poux, Tiphaine. "Study of the oxygen reduction on perovskite-type oxides in alkaline media." Thesis, Strasbourg, 2014. http://www.theses.fr/2014STRAF001/document.

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La cinétique lente de la réduction de l’oxygène (ORR) est en grande partie responsable de la perte d’énergie de nombreux systèmes de conversion tels que les piles à combustible. Parmi les possibles catalyseurs de l’ORR, les oxydes de type pérovskite sont des candidats prometteurs en milieu alcalin. La présente thèse est consacrée à l’étude de l’activité, du mécanisme et de la stabilité de pérovskites à base de Co et Mn pour l’ORR. Grâce aux techniques d’électrode tournante à disque et disque-anneau (R(R)DE), les études de l’ORR et des transformations d’HO2- sur les couches minces de pérovskite/carbone dans une solution de NaOH ont montré qu’O2 est réduit en OH- via un mécanisme « en série » avec formation d’HO2- intermédiaire. Pour des quantités d’oxyde suffisantes, HO2- est ensuite réduit, ce qui résulte en un mécanisme apparent de 4 électrons. Dans ces électrodes, le carbone joue un double rôle. Il augmente l’activité électrocatalytique en améliorant le contact électrique et il est impliqué dans le mécanisme de l’ORR en catalysant la réduction d’O2 en HO2-, surtout pour les pérovskites à base de cobalt qui sont considérablement moins actives que celles à base de Mn. Néanmoins, l’électrocatalyse de l’ORR semble dégrader les sites actifs des pérovskites
The sluggish kinetics of the oxygen reduction reaction (ORR) is largely responsible for the energy losses in energy conversion systems such as fuel cells. Among possible inexpensive catalysts for the ORR, perovskite oxides are promising electrocatalysts in alkaline media. The present thesis is devoted to the investigation of the ORR activity, mechanism and stability of some Co and Mn-based perovskites. The rotating (ring) disk electrode (R(R)DE) studies of the ORR and the HO2- transformations on perovskite/carbon thin layers in NaOH electrolyte prove that O2 is reduced to OH- via a “series” pathway with the HO2- intermediate. For high oxide loadings, the formed HO2- species are further reduced to give a global 4 electron pathway. In these electrodes, carbon plays a dual role. It increases the electrocatalytic activity by improving the electrical contact and it is involved in the ORR mechanism by catalyzing the reduction of O2 into HO2-, especially for Co-based perovskites which display lower reaction rates than Mn-based perovskites

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Blauch, David N. Anson Fred C. Anson Fred C. "Part I. Improvements in the rotation-rate step experiment for the evaluation of diffusion coefficients at rotating disk electrodes. : Part II. Ion-pairing and electric field effects on electron hopping in the Nafion-tris(2,2'-bipyridine)osmium(3+/2+) system /." Diss., Pasadena, Calif. : California Institute of Technology, 1991. http://resolver.caltech.edu/CaltechETD:etd-06152007-081035.

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29

Foley, Edward L. "A Rotating Aperture Mask for Small Telescopes." DigitalCommons@CalPoly, 2019. https://digitalcommons.calpoly.edu/theses/2105.

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Observing the dynamic interaction between stars and their close stellar neighbors is key to establishing the stars’ orbits, masses, and other properties. Our ability to visually discriminate nearby stars is limited by the power of our telescopes, posing a challenge to astronomers at small observatories that contribute to binary star surveys. Masks placed at the telescope aperture promise to augment the resolving power of telescopes of all sizes, but many of these masks must be manually and repetitively reoriented about the optical axis to achieve their full benefits. This paper introduces a design concept for a mask rotation mechanism that can be adapted to telescopes of different types and proportions, focusing on an implementation for a Celestron C11 Schmidt–Cassegrain optical tube assembly. Mask concepts were first evaluated using diffraction simulation programs, later manufactured, and finally tested on close double stars using a C11. An electronic rotation mechanism was designed, produced, and evaluated. Results show that applying a properly shaped and oriented mask to a C11 enhances contrast in images of double star systems relative to images captured with the unmasked telescope, and they show that the rotation mechanism accurately and repeatably places masks at target orientations with minimal manual effort. Detail drawings of the mask rotation mechanism and code for the software interface are included.

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Asp, Elina. "Drift-Type Waves in Rotating Tokamak Plasma." Doctoral thesis, Uppsala University, Department of Astronomy and Space Physics, 2003. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-3400.

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The concept of energy production through the fusion of two light nuclei has been studied since the 1950’s. One of the major problems that fusion scientists have encountered is the confinement of the hot ionised gas, i.e. the plasma, in which the fusion process takes place. The most common way to contain the plasma is by using at magnetic field configuration, in which the plasma takes a doughnut-like shape. Experimental devices of this kind are referred to as tokamaks. For the fusion process to proceed at an adequate rate, the temperature of the plasma must exceed 100,000,000C. Such a high temperature forces the plasma out of thermodynamical equilibrium which plasma tries to regain by exciting a number of turbulent processes. After successfully quenching the lager scale magnetohydrodynamic turbulence that may instantly disrupt the plasma, a smaller scale turbulence revealed itself. As this smaller scale turbulence behaved contrary to the common theory at the time, it was referred to as anomalous. This kind of turbulence does not directly threaten existents of the plasma, but it allows for a leakage of heat and particles which inhibits the fusion reactions. It is thus essential to understand the origin of anomalous turbulence, the transport it generates and most importantly, how to reduce it. Today it is believed that anomalous transport is due to drift-type waves driven by temperature and density inhomogeneities and the theoretical treatment of these waves is the topic of this thesis.

The first part of the thesis contains a rigorous analytical two-fluid treatment of drift waves driven solely by density inhomogeneities. Effects of the toroidal magnetic field configuration, the Landau resonance, a peaked diamagnetic frequency and a sheared rotation of the plasma have been taken into account. These effects either stabilise or destabilise the drift waves and to determine the net result on the drift waves requires careful analysis. To this end, dispersion relations have been obtained in various limits to determine when to expect the different effects to be dominant. The main result of this part is that with a large enough rotational shear, the drift waves will be quenched.

In the second part we focus on temperature effects and thus treat reactive drift waves, specifically ion temperature gradient and trapped electron modes. In fusion plasmas the α-particles, created as a by-product of the fusion process, transfer the better part of their energy to the electrons and hence the electron temperature is expected to exceed the ion temperature. In most experiments until today, the ion temperature is greater than the electron temperature and this have been proven to improve the plasma confinement. To predict the performance of future fusion plasmas, where the fusion process is ongoing, a comprehensive study of hot-electron plasmas and external heating effects have been carried out. Especially the stiffness (heat flux vs. inverse temperature length scale) of the plasma has been examined. This work was performed by simulations done with the JETTO code utilising the Weiland model. The outcome of these simulations shows that the plasma response to strong heating is very stiff and that the plasma energy confinement time seems to vary little in the hot-electron mode.

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Yun, Yifeng. "Characterization of crystalline materials by rotation electron diffraction : Phase identification and structure determination." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-108930.

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Electron crystallography is powerful for determination of complex structures. The newly-developed 3D electron diffraction (ED) methods make structure determination from nano- and micron-sized crystals much easier than using other methods, for example X-ray diffraction. Almost complete 3D ED data can be collected easily and fast from crystals at any arbitrary orientations. Dynamical effects are largely reduced compared to zonal ED patterns. 3D ED is powerful for phase identification and structure solution from individual nano- and micron-sized crystals, while powder X-ray diffraction (PXRD) provides information from all phases present in the samples. 3D ED methods and PXRD are complementary and their combinations are promising for studying multiphasic samples and complicated crystal structures. In this thesis, the feasibility and capability of 3D ED methods, specifically rotation electron diffraction (RED), in phase identification and structure determination of different kinds of crystalline materials with nano- or submicrometer-sized crystals are investigated. Experimental conditions for RED data collection and data processing in relation to data quality, as well as the challenges in the applications of RED are discussed. RED was combined with PXRD to identify phases from as-synthesized samples and to characterize atomic structures of eleven crystalline compounds. It was shown to be possible to identify as many as four distinct compounds within one sample containing submicron-sized crystals in a Ni-Se-O-Cl system. RED was also used to determine unit cell and symmetry of isoreticular metal-organic frameworks (SUMOF-7) and solve five zeolite structures with new frameworks, ITQ-51, ITQ-53, ITQ-54, EMM-23 and EMM-25 and that of a metal-organic framework (MOF), SUMOF-7I. The structure of an open-framework germanate SU-77 was solved by combining RED with PXRD. The structures of the zeolites and SU-77 were confirmed by Rietveld refinement against PXRD. High-resolution transmission electron microscopy was used to confirm the structure models of ITQ-51, EMM-25 and SUMOF-7I.

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Submitted. Paper 4: Accepted. Paper 6: Manuscript. Paper 7: Epub ahead of print. Paper 9: Manuscript. Paper 11: Manuscript.

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32

BEZERRA, CAVALCANTI ELIANE. "Transfert de matiere aux electrodes d'une cellule combinant ecoulement force et rotation." Rennes 1, 1997. http://www.theses.fr/1997REN10126.

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La these se rapporte a l'etude experimentale du transfert de matiere entre un liquide et les surfaces d'une paire de disques paralleles. L'un des disques peut etre mis en rotation, l'autre restant fixe ; l'ecoulement du liquide peut etre force, et la paire de disques peut appartenir a un ensemble de paires identiques disposees en serie dans un conteneur cylindrique. La connaissance des performances en transfert de matiere de telles geometries aurait son utilite dans la conception de reacteurs electrochimiques. L'etude comporte quatre etapes qui se rapportent, respectivement, a une situation hydrodynamique differente et chaque fois un peu plus complexe. C'est ainsi que l'on etudie l'influence, sur le transfert de matiere, de la rotation de l'un des disques dans un espace cylindrique ferme, de l'ecoulement radial force divergent ou convergent entre deux disques fixes paralleles, de l'ecoulement radial force, successivement divergent et convergent, dans un ensemble vertical de paires identiques de disques et d'anneaux alternes, et placees dans un conteneur cylindrique, et enfin de la combinaison de l'ecoulement force et de la rotation conjointe de l'ensemble des disques. Dans chaque etape, on fait varier les parametres experimentaux, dont les parametres geometriques, de maniere a faire apparaitre leur influence sur le transfert de matiere entre le liquide et la surface consideree sur le disque ou sur l'anneau. Si la majorite des mesures sont de type global, quelques etudes locales ont aussi ete effectuees, d'une part pour atteindre le frottement local au niveau du disque fixe de l'espace cylindrique ferme, d'autre part pour avoir des distributions de coefficients locaux de transfert de matiere au niveau des deux disques du systeme qui met en jeu un ecoulement force entre disques fixes paralleles. Les coefficients de transfert de matiere sont mesures par une methode electrochimique. Les resultats sont presentes et discutes sous la forme de correlations empiriques entre nombres adimensionnels. La comparaison graphique avec d'autres resultats de la litterature souligne le caractere clarificateur et complementaire des resultats obtenus dans la these.

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33

Briega-Martos, Valentín. "Unraveling the oxygen reduction reaction mechanism: occurrence of a bifurcation point before hydrogen peroxide formation." Doctoral thesis, Universidad de Alicante, 2019. http://hdl.handle.net/10045/102311.

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En la presente tesis doctoral se realiza un estudio detallado sobre el mecanismo de la reacción de reducción de oxígeno (ORR) en electrodos monocristalinos de platino. Para ello, se han realizado medidas electroquímicas usando la configuración de electrodo rotatorio de menisco colgante (HMRDE) con superficies con distinta estructura superficial y variando condiciones de la disolución de trabajo como el pH, fuerza iónica o la ausencia o presencia de bromuros. La conclusión principal que se extra de estos experimentos es la posibilidad de la existencia de un punto de bifurcación en el mecanismo, implicando el intermedio OOH, antes de la formación de peróxido de hidrógeno. Además, también se estudia la ORR y la reacción de oxidación de ácido fórmico en electrodos monocristalinos de Pt en presencia de acetonitrilo, como estudio previo al estudio de estas reacciones en disolventes orgánicos con pequeñas cantidades de agua. Por último, se estudia la ORR en un Aza-CMP, lo cual permite obtener información fundamental que se puede aplicar en estudios sobre el mecanismo de la ORR en los sitios activos de materiales de carbón funcionalizados con nitrógeno.

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34

Sun, Xiaojing. "Study of the oxygen reduction reaction on platinum with scanning electrochemical microscopy and rotating disk voltammetry." Master's thesis, Mississippi State : Mississippi State University, 2007. http://library.msstate.edu/etd/show.asp?etd=etd-09242007-102717.

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35

Casadei, Matteo. "Muon Spin Rotation (uSR) investigation of electron-doped iron-oxypnictide superconductors." Master's thesis, Alma Mater Studiorum - Università di Bologna, 2021.

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In the last ten years, the Fe-based superconductors have been extensively investigated both from the experimental and theoretical point of view, and many studies have been devoted to investigate the intimate interplay between the magnetic and superconducting phases. However, many aspects of their phenomenology are still unclear. In this thesis work we focused onto a specific material family, namely the LaFeAsO1−xFx (1111), to perform a systematic experimental investigation of the superconducting and magnetic microscopic properties as a function of the Fluorine doping. We considered the doping range 0.04 < x < 0.15, namely from the emergence of superconductivity to the so-called overdoped regime. We used Muon Spin Rotation (µSR) spectroscopy, which is a very powerful local probe to study the microscopic superconducting and magnetic properties of materials. In particular, we systematically studied the doping dependence of i) the superconducting gap and the London penetration depth, related to the superconducting density ns, via the analysis of the muon depolarization rate, and of ii) the local magnetic susceptibility, through the local field probed at the muon site. The results suggest a possible change from s-wave to d-wave character when the superconducting critical temperature Tc is reduced. The normalized Tc as a function of the superfluid density for different Ln-1111 families collapses onto a single phenomenological universal curve that indicates a crossover from the so called-Uemura (Tc∝ns) to the BCS (Tc∿const) regime. This is a phenomenological original outcome of this work. Another important result of this thesis is the observation of a rehentrant paramagnetic behavior in all the samples, more evident for compositions with high Tc. We argued that it may arise from residual magnetic correlations which survive up the to optimally doped regime and beyond. The interplay between this anomalous rehentrant behavior and superconductivity deserves further investigation.

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Macpherson, M. J. D. "Measurement of PNC optical rotation at 876 nm in atomic bismuth." Thesis, University of Oxford, 1988. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382667.

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Nemra, Ghinwa. "Comportement electrochimique de nouveaux complexes a liaison pd-pd et pt-pd stabilises par des ligands bidentates ph : :(2)pch::(2)pph::(2)." Strasbourg 1, 1986. http://www.theses.fr/1986STR13055.

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L'etude des proprietes redox d'une vingtaine de complexes mono-, di-, tri- et tetranucleaires du palladium et du platine a ete effectuee par des methodes electrochimiques (electrode a disque tournant, voltamperometrie cyclique et coulometrie) associees a des methodes spectroscopiques (spectrophotometrie d'absorption electronique, rpe et rmn). Les differents mecanismes des reactions redox ont ete etablis en fonction de la nature des metaux et des ligands dans le complexe. On montre qu'on peut modifier de maniere controlee les potentiels d'oxydoreduction et la reversibilite des transferts de charge par un choix convenable de parametres: metaux, ligands (phosphine, co) et milieu d'etude. Les resultats obtenus contribuent a l'etude de la reactivite electrochimique de la liaison metal-metal dans les complexes des metaux de transition

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Coche, Liliane. "Préparation et étude électrochimique d'électrodes modifiées par des films de polymères rédox : application à la catalyse électrochimique rédox." Grenoble 1, 1987. http://www.theses.fr/1987GRE10046.

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Preparation d'electrodes de platine, palladium et rhodium modifiees par des films de polypyrrole et de poly (pyrrole-crologene). Application a la reduction electrochimique en milieu acetonitrile du dibromo-1,2 diphenyl-1,2 ethane

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39

Peng, Fei. "Structure determination of beam sensitive crystals by rotation electron diffraction : the impact of sample cooling." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-145636.

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Electron crystallography is complementary to X-ray crystallography. Single crystal X-ray diffraction requires the size of a crystal to be larger than about 5 × 5 × 5 μm3 while a TEM allows a million times smaller crystals being studied. This advantage of electron crystallography has been used to solve new structures of small crystals. One method which has been used to collect electron diffraction data is rotation electron diffraction (RED) developed at Stockholm University. The RED method combines the goniometer tilt and beam tilt in a TEM to achieve 3D electron diffraction data. Using a high angle tilt sample holder, RED data can be collected to cover a tilt range of up to 140o. Here the crystal structures of several different compounds have been determined using RED. The structure of needle-like crystals on the surface of NiMH particles was solved as La(OH)2. A structure model of metal-organic layers has been built based on RED data. A 3D MOF structure was solved from RED data. Two halide perovskite structures and two newly synthesized aluminophosphate structures were solved. For those beam sensitive crystals characterized here, sample cooling down to -170oC was used to reduce the beam damage. The low temperature not only reduces electron beam damage, but also keeps the structure more stable in the high vacuum in a TEM and improves the quality of the diffraction data. It is shown that cooling can improve the resolution of diffraction data for MOFs and zeolites, for samples undergoing phase changes at low temperature, the data quality could be worse by cooling. In summary, cooling can improve the ED data quality as long as the low temperature does not trigger structural changes.

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 1: Manuscript. Paper 3: Submitted.

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Yokoyama, Koji. "Muon probes of spin-polarized electrons in GaAs." Diss., UC access only, 2009. http://proquest.umi.com/pqdweb?index=104&did=1907186881&SrchMode=1&sid=1&Fmt=7&retrieveGroup=0&VType=PQD&VInst=PROD&RQT=309&VName=PQD&TS=1270484411&clientId=48051.

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Thesis (Ph. D.)--University of California, Riverside, 2009.
Includes abstract. Includes bibliographical references (leaves 121-123). Issued in print and online. Available via ProQuest Digital Dissertations.

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Kersell, Heath Ryan. "Investigations on the Complex Rotations of Molecular Nanomachines." Ohio University / OhioLINK, 2011. http://rave.ohiolink.edu/etdc/view?acc_num=ohiou1307126123.

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Wang, Yunchen. "3D Electron Diffraction : Application and Development towards High-quality Structure Determination." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-147732.

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Electron crystallography has been proven to be effective for structure determination of nano- and micron-sized crystals. In the past few years, 3D electron diffraction (3DED) techniques were used for the structure solution of various types of complex structures such as zeolites, metal-organic frameworks (MOF) and pharmaceutical compounds. However, unlike X-ray crystallography, electron diffraction has not yet become an independent technique for a complete structure determination due to relatively poorer diffraction intensities and often powder X-ray diffraction data are used for structure validation and refinement. Electron beam damage to the structures that are sensitive to high energy electrons and dynamical scattering are important factors to lead to the deviation of electron diffraction intensities from the squared amplitudes of the structure factors. In this thesis, we investigate various aspects around the 3D electron diffraction data quality and strategies for obtaining better data and structure models. We combined 3D electron diffraction methods and powder X-ray diffraction to determine the structure of an open-framework material and discussed the difficulties and limitations of electron diffraction for beam sensitive materials. Next, we illustrated the structure determination of a pharmaceutical compound, bismuth subgallate, using 3D electron diffraction. While severe beam damage and diffuse scattering were observed in the dataset collected with the conventional rotation electron diffraction (RED) method, the continuous rotation electron diffraction (cRED) method coupled with sample cooling significantly improved the data quality and made the structure solution possible. In order to better understand the potentials and limitations of the continuous rotation method, we collected multiple datasets from different crystals of a known structure and studied the data quality by evaluating the accuracy of the refined structure models. To tackle dynamical scattering in electron diffraction data, we explored a routine for structure refinement with dynamical intensity calculation using RED data from a known structure and discussed its potentials and limitations.

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.

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Stoschus, Henning [Verfasser], Ulrich [Akademischer Betreuer] Samm, and Georg [Akademischer Betreuer] Pretzler. "Electron Transport in the Plasma Edge with Rotating Resonant Magnetic Perturbations at the TEXTOR Tokamak / Henning Stoschus. Gutachter: Ulrich Samm ; Georg Pretzler." Düsseldorf : Universitäts- und Landesbibliothek der Heinrich-Heine-Universität Düsseldorf, 2011. http://d-nb.info/1015458858/34.

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Giri, Rakshyakar. "Electron and nuclear spin dynamics in GaAs microcavities." Thesis, Montpellier 2, 2013. http://www.theses.fr/2013MON20037/document.

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Nous avons obtenu des angles de rotation Faraday (RF) allant jusqu'à 19° par orientation optique d'un gaz d'électrons dans GaAs de type n inclus dans une microcavité (Q=19000), sans champ magnétique. Cette forte rotation est obtenue en raison des multiples allers-retours de la lumière dans la cavité. Nous avons également démontré la commutation optique rapide de la RF à l'échelle sub-microseconde en échantillonnant le signal de RF sous excitation impulsionnelle mono-coup. De la dépolarisation de la RF en champ magnétique transverse, nous avons déduit un temps de relaxation de spin de 160 ns. Le concept de section efficace de RF, coefficient de proportionnalité entre l'angle RF, la densité de spin électronique, et le chemin parcouru, a été introduit. La section efficace de RF, qui définit l'efficacité du gaz d'électrons à produire une RF, a été estimée quantitativement, et comparée avec la théorie. Nous avons également démontré la possibilité de mesurer de manière non destructive l'aimantation nucléaire dans GaAs-n, via la RF amplifiée par la cavité. Contrairement aux méthodes existantes, cette détection ne nécessite pas la présence d'électrons hors équilibre. Par cette technique nous avons étudié la dynamique de spin nucléaire dans GaAs-n avec différents dopages. Contrairement à ce qu'on pourrait attendre, le déclin de la RF nucléaire est complexe et consiste en deux composantes ayant des temps de relaxation très différents. Deux effets à l'origine de la RF nucléaire sont identifiés: le splitting de spin de la bande de conduction, et la polarisation en spin des électrons localisés, tous deux induits par le champ Overhauser. Le premier effet domine la RF nucléaire dans les deux échantillons étudiés, tandis que la RF induite par les électrons localisés n'a été observée que dans l'échantillon métallique
We obtained Faraday rotation (FR) up to 19° by using optical orientation of electron gas in n-doped bulk GaAs confined in a microcavity (Q=19000), in the absence of magnetic field. This strong rotation is achieved because the light makes multiple round trips in the microcavity. We also demonstrated fast optical switching of FR in sub-microsecond time scale by sampling the FR in a one-shot experiment under pulsed excitation. From the depolarization of FR by a transverse magnetic field, we deduce electron spin relaxation time of about 160 ns. A concept of FR cross-section as a proportionality coefficient between FR angle, electron spin density and optical path is introduced. This FR cross-section which defines the efficiency of spin polarized electrons in producing FR was estimated quantitatively and compared with theory. We also demonstrated non-destructive measurement of nuclear magnetization in n-GaAs via cavity enhanced FR. In contrast with the existing optical methods, this detection scheme does not require the presence of detrimental out-of-equilibrium electrons. Using this technique, we studied nuclear spin dynamics in n-GaAs with different doping concentrations. Contrary to simple expectation, the nuclear FR is found to be complex, and consists of two components with vastly different time constants. Two effects at the origin of FR have been identified: the conduction band spin splitting and the localized electron spin polairzation both induced by the Overhauser field. The first effect dominates the FR in both studied samples, while the FR induced by the localized electrons has been observed only in the metallic sample

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45

Conti, Alfredo. "Tecniche della manifattura additiva - applicazioni in ambito aeronautico e aerospaziale." Bachelor's thesis, Alma Mater Studiorum - Università di Bologna, 2017. http://amslaurea.unibo.it/13306/.

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Il potenziale delle nuove tecnologie digitali applicate al settore industriale ha consentito di ridurre enormemente la durata dei cicli produttivi grazie alla rapida gestione di quantità di dati sempre più considerevoli attraverso l’introduzione delle Macchine a Controllo Numerico (Computer Numerical Control – CNC). Nel corso delle ultime tre decadi, l’industria manifatturiera ha subito notevoli e sostanziali cambiamenti grazie ad una sempre più forte connessione con il mondo dell’informatica. La più grande rivoluzione in tale ambito è stata segnata dall’avvento della Manifattura Additiva (Additive Manufacturing - AM), conosciuta sotto diversi nomi, tra i quali Prototipazione Rapida (Rapid Prototyping), Manifattura Rapida (Rapid Manufacturing) o Libera Fabbricazione di Forme (Free Form Fabrication). Materia di ricerca e sviluppo sin dalla fine degli anni ’80, la Manifattura Additiva consente la creazione di elementi fisici tridimensionali partendo da modelli CAD attraverso la sovrapposizione successiva di materiale strato per strato (layer by layer), offrendo i benefici di una elevata flessibilità geometrica degli elaborati, altrimenti irraggiungibile attraverso le tradizionali tecniche di Manifattura Sottrattiva operanti per asportazione di materiale. In seguito ad intensive ricerche, progressi significativi sono stati fatti nello sviluppo e nella commercializzazione di nuovi ed innovativi processi AM.

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Simard, Guy. "La modélisation de la combustion dans un four de calcination de coke de pétrole /." Thèse, Chicoutimi : Université du Québec à Chicoutimi, 1992. http://theses.uqac.ca.

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Láska, Samuel. "Segmentace struktur mikroskopických dat mozku." Master's thesis, Vysoké učení technické v Brně. Fakulta elektrotechniky a komunikačních technologií, 2013. http://www.nusl.cz/ntk/nusl-220342.

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This thesis is involved in image processing of medical data and its implementation using Java programming language. The main contribution of this thesis is creation of algorithms for feature extraction from 3D data and subsequent verification of the results for the issue of imagining 3D brain data, and creation of image filters and their implementation in the program RapidMiner. Consequently, the segmentation process is created at the 2D and 3D level, and output of 3D level segmentation are segmented brain structures. Furthermore, segmentation algorithms were compared on the basis of the final form of segmented structures and this approach was compared with other works.

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Rattananakin, Pornpun. "Ab initio study of the rotation around the carbon-carbon double bond in push-pull systems." Diss., Mississippi State : Mississippi State University, 2006. http://sun.library.msstate.edu/ETD-db/ETD-browse/browse.

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石田, 幸男, Yukio ISHIDA, 剛志井上, and Tsuyoshi INOUE. "動吸振器を用いた非線形回転軸系の制振." 日本機械学会, 2002. http://hdl.handle.net/2237/9050.

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Guo, Peng. "Structure Determination and Prediction of Zeolites : A Combined Study by Electron Diffraction, Powder X-Ray Diffraction and Database Mining." Doctoral thesis, Stockholms universitet, Institutionen för material- och miljökemi (MMK), 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-127750.

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Zeolites are crystalline microporous aluminosilicates with well-defined cavities or channels of molecular dimensions. They are widely used for applications such as gas adsorption, gas storage, ion exchange and catalysis. The size of the pore opening allows zeolites to be categorized into small, medium, large and extra-large pore zeolites. A typical zeolite is the small pore silicoaluminophosphate SAPO-34, which is an important catalyst in the MTO (methanol-to-olefin) process. The properties of zeolite catalysts are determined mainly by their structures, and it is therefore important to know the structures of these materials in order to understand their properties and explore new applications. Single crystal X-ray diffraction has been the main technique used to determine the structures of unknown crystalline materials such as zeolites. This technique, however, can be used only if crystals larger than several micrometres are available. Powder X-ray diffraction (PXRD) is an alternative technique to determine the structures if only small crystals are available. However, peak overlap, poor crystallinity and the presence of impurities hinder the solution of structures from PXRD data. Electron crystallography can overcome these problems. We have developed a new method, which we have called “rotation electron diffraction” (RED), for the automated collection and processing of three-dimensional electron diffraction data. This thesis describes how the RED method has been applied to determine the structures of several zeolites and zeolite-related materials. These include two interlayer expanded silicates (COE-3 and COE-4), a new layered zeolitic fluoroaluminophosphate (EMM-9), a new borosilicate (EMM-26), and an aluminosilicate (ZSM-25). We have developed a new approach based on strong reflections, and used it to determine the structure of ZSM-25, and to predict the structures of a series of complex zeolites in the RHO family. We propose a new structural principle that describes a series of structurally related zeolites known as “embedded isoreticular zeolite structures”, which have expanding unit cells. The thesis also summarizes several common structural features of zeolites in the Database of Zeolite Structures.

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 2: Manuscript. Paper 3: Manuscript.

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Dissertations / Theses on the topic 'Rotating Electrode'

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