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Fotocatálise heterogênea no polimento de efluentes sintéticos de curtume: alternativa para minimizar impactos ambientaisPascoal, Salomão de Andrade 23 February 2006 (has links)
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Previous issue date: 2006-02-23 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / The industry is a section of the contemporary society with great pollutant potential of the
environment, especially of the aquatic ecosystems. The tanning industries are big producing of
dejections with significant amounts of organic matter and of chrome. The conventional processes
of treatment applied those dejections, not always they possess good effectiveness. Actuality, the
Advanced Oxidation Processes represent an excellent alternative of tertiary treatment. In the
present study, the application of the heterogeneous photocatalysis was evaluated, being used a
photocatalyst (TiO2) immobilized, in the tertiary treatment of synthetic liquid effluents
representative of tanning industries. It was aimed at to remove Cr(VI) and organic matter. The
photocatalytic reactor was of the type Fixed Bed of Fine Film, built with a plate of glass arrayed
for the fixation of TiO2. It was adopted as radiation sources, the sun and lamps issuing of UV
radiation (λ= 250 nm). The smallest values of removal effectiveness for Cr(VI) they were of 62%
and 51% and of DOC they were from 60% and 53% to the experiments done with radiation UV
originating from of the sun and of lamps, respectively. The results of the parameters related to the
reduction phases and oxidation of the heterogeneous photocatalysis, they showed that the
exhibition in the sun, he/she has effectiveness of larger relative removal than the exhibition to
UV lamps. The data of relative removal of Cr(VI) and of DOC and the constants kinetics of these
parameters, they indicated that the adopted experimental configurations optimized the phase of
reduction of the heterogeneous photocatalysis. / A indústria é um setor da sociedade contemporânea com grande potencial poluidor do meio
ambiente, especialmente dos ecossistemas aquáticos. As indústrias de curtume são grandes
produtoras de dejetos com significativas quantidades de material orgânico e de cromo. Os
processos convencionais de tratamento aplicados a esses dejetos, nem sempre possuem boa
eficácia. Atualmente, os Processos Oxidativos Avançados representam uma excelente alternativa
de tratamento terciário. No presente estudo, avaliou-se a aplicação da fotocatálise heterogênea,
usando-se um fotocatalisador (TiO2) imobilizado, no tratamento final de efluentes líquidos
sintéticos representativos de indústrias de curtume. Objetivou-se remover Cr(VI) e matéria
orgânica. O fotorreator foi do tipo Leito Fixo de Filme Fino, construído com uma placa de vidro
jateado para a fixação do TiO2. Adotou-se como fontes de radiação, o sol e lâmpadas germicidas
emissoras de radiação UV (λ= 250 nm). Os menores valores de eficácia de remoção para Cr(VI)
foram de 62% e 51% e de DQO foram de 60% e 53% para os experimentos feitos com radiação
UV oriundas do sol e de lâmpadas, respectivamente. Os resultados dos parâmetros relacionados
às fases de redução e oxidação da fotocatálise heterogênea, mostraram que a exposição ao sol,
tem eficácia de remoção relativa maior do que a exposição à lâmpadas UV. Os dados de remoção
relativa de Cr(VI) e de DQO e as constantes cinéticas destes parâmetros, indicaram que as
configurações experimentais adotadas otimizaram a fase de redução da fotocatálise heterogênea.
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L?vi-Strauss Mitol?gicas: Mito e m?sica entre o largo e o prest?ssimoMelo, Bet?nia Maria Franklin de 20 December 2012 (has links)
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Previous issue date: 2012-12-20 / This study was elaborated based on our research of the work Mithologiques by the anthropologist Claude L?vi-Strauss (1908-2009), which affirms that languages, indigenous myths and music are related. He proposes that the understanding of myths occurs in a similar manner as with an orchestral score. In the course of his tetralogy we investigated the musical terms used in the analysis and in the division of the chapters, especially in the first volume of his work. Several compositional procedures and forms are named. Composers in pairs are categorized: Sebastian Bach for the code, Ludwig van Beethoven for the message, and Richard Wagner for the myths. In this deduction, we structured in parts: theme and variations, sonata and fugue with the aforementioned composers. Within the greatness of anthropological study, from among over 800 myths, we selected the first five of the indigenous tribe Bororo to discuss within the Theme and Variation segment. In the Sonata part there are two myths with the same theme: The wife of the jaguar which relates to the compositional structure, and four myths about The origin of women. Finally, in the segment related to the Fugue, we collected four myths that address The shortness of life. Honoring the many terms expressed in opposition, contrast, or symmetry under consideration in Levi-Strauss work, we entitled this thesis emphasizing the migration between the tempos Largo and Prest?ssimo as these are oppositional presentations in music. Fifteen musical myths accompany the work supported by selected narratives. In light of this we questioned, we questioned: how are incest, murder and other events part of a society that elevates nature as an extension of life itself? And how did L?vi-Strauss think that anthropology harmonized with music? In the preparation of this study, philosophers like Peter Sloterdijk discuss the circular territory of Mythology / Este estudo foi elaborado com base em nossas pesquisas na obra Mitol?gicas do antrop?logo Claude L?vi-Strauss (1908-2009), na qual afirma que linguagens, mitos ind?genas e m?sica est?o relacionados. Ele prop?e que a compreens?o dos mitos ocorre de maneira similar com a partitura orquestral. No decorrer da sua tetralogia, investigamos termos da m?sica usados na an?lise e na divis?o dos cap?tulos, principalmente do primeiro volume da obra. V?rios procedimentos de composi??o e formas est?o nomeados. Compositores em pares s?o categorizados: Sebastian Bach para o c?digo, Ludwig van Beethoven para a mensagem e Richard Wagner para os mitos. Nesta dedu??o, estruturamos em partes: tema e varia??es, sonata e fuga com os compositores citados. Na grandeza do estudo antropol?gico, entre mais de 800 mitos, selecionamos os cinco primeiros da tribo ind?gena Bororo para discutir na parte Tema e Varia??o. Na parte Sonata h?: dois mitos com mesmo tema, A esposa do jaguar, para relacionar ? estrutura composicional e quatro mitos sobre A origem das mulheres. Por ?ltimo, na Fuga recolhemos quatro mitos que abordam A vida breve. Diante dos termos dados em oposi??o, contrastes ou simetria presentes na obra, demos o t?tulo a este trabalho migrando os andamentos largo e prest?ssimo por se apresentarem na m?sica tamb?m em opostos. Quinze mitos musicais acompanham o trabalho apoiados nas narrativas selecionadas. Para tanto, questionamos como incesto, assassinato e outros acontecimentos fazem parte da sociedade ind?gena que eleva a natureza como extens?o da pr?pria vida? E como L?vi- Strauss pensou a antropologia harmonizada ? m?sica? Na elabora??o deste estudo, pensadores como Peter Sloterdijk dialogam o territ?rio redondo da Mitologia
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Etude cinétique d'extraction de l'uranium(VI) et du plutonium(IV) par des extractants monoamides / Kinetics extraction of uranium(VI) and plutonium(IV) using N,N-dialkylamidesBerlemont, Romain 28 September 2015 (has links)
Ces travaux de thèse, effectués dans le cadre des études sur le retraitement des combustibles nucléaires usés par extraction-liquide-liquide, concernent l’étude cinétique d’extraction de l’uranium(VI) et du plutonium(IV) en milieu acide nitrique par un mélange d’extractants de type monoamide. Trois techniques ont été utilisées pour étudier les cinétiques d’extraction et identifier les régimes de transfert : la méthode de la goutte unique, la cellule d’extraction de Nitsch et la cellule à membrane tournante (RMC). Les résultats obtenus avec la goutte unique indiquent que les cinétiques de transfert d’U(VI) et Pu(IV) sont proches. Une étude hydrodynamique des gouttes et la modélisation du transfert de l’U(VI) ont montré que la présence d’une circulation interne à la goutte diminue les résistances diffusionnelles pour des tailles de goutte croissantes. L’influence de la concentration d’U(VI) dans le solvant sur la cinétique d’extraction a montré que le transfert d’U(VI) et Pu(IV) ralentit lorsque la concentration d’U(VI) en phase organique et la viscosité augmentent. L’ensemble de ces résultats couplé à l’étude du transfert de l’U(VI) par la cellule de Nitsch conduisent à supposer une cinétique gouvernée par la diffusion principalement localisée dans la phase organique. Les études réalisées avec la RMC ont permis de déterminer la constante chimique d’extraction de l’U(VI), du même ordre de grandeur que les cinétiques obtenues par la goutte unique et de confirmer la présence d’une réaction chimique interfaciale. Enfin, le transfert d’U(VI) et Pu(IV) s’avère 3 fois plus lent que celui par le TBP mais reste adapté pour un procédé d’extraction à l’échelle industrielle. / This thesis was conducted in the framework of the reprocessing of spent nuclear fuels. The kinetics extraction of uranium(VI) and plutonium(IV) by N,N-dialkylamides or monoamides in an aliphatic diluent were studied from an aqueous nitric solution using 3 different techniques: “single drop technique”, Nitsch cell and Rotating Membrane Cell (RMC). All these experiments were useful to attempt the identification of the transfer process between the phases which can be controlled by kinetic or diffusional regime. The kinetics of extraction of U(VI) by monoamides solvent seems to be similar to that of the Pu(IV). In general, molecular diffusion in organic phase slows down the extraction process and the limiting thickness of organic phase increases with solvent viscosity. The process in “single drop technique” seems to be controlled not only by diffusion but also by the chemical reaction. Then the extraction kinetics of U(VI) has been carried out by Nitsch cell and the RMC. Diffusionnal regime is the limiting step in Nitsch cell and the results confirm that molecular diffusion in organic phase should mainly control the kinetics transfer. Then experiments performed by the RMC indicate that the kinetics is in the same order as transfer coefficient obtained by “single drop” and the chemical reaction occurs at the interface. Finally, these results were compared with data obtained with a TBP solvent (tributyl phosphate) currently used in the PUREX process in order to estimate the interest of such a new solvent. The kinetics of extraction of U(VI) by this monoamide-based solvent is three times lower that of the TBP 30 % but remains fast and suitable for a future industrial process.
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Utilização de escamas do peixe corvina para adsorção de Cr(VI) em meio aquoso - cinética e termodinâmica por calorimetria isotérmica contínuaMoura, Karine Oliveira 18 February 2011 (has links)
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / Adsorption has become a key process for the removal of very low amounts of undesirable components from waters and wastewaters and in the sense for being environmental friendly as well. This work has as aim
the study of some properties of scales of Corvina fish (Micropogonias furnieiri) as a new adsorbent to remove Cr(VI) from aqueous solutions. The Corvina scales were characterized by thermogravimetry, Fourier transformed infrared spectroscopy, scanning electron microscopy with energydispersive electron probe X-ray analysis, X-ray diffraction and pH of point of zero charge. The characterization results have suggested that the Corvina
scales present two main structural phases, one being rich in type I collagen and one rich in apatites. Sorption studies of Cr(VI) using the batch methodology have indicated that Cr(VI) sorption increased when both initial Cr(VI) concentration in solution and temperature increase. Calorimetric measurements of scales water wetting have pointed out slightly exothermic results and degrees of wetting from 30.8 to 45.3 %. The kinetic data of Cr(VI) sorption were best fitted to the Avrami
exponential model. The equilibrium data of Cr(VI) sorption were best fitted to both the Langmuir-Freundlich and the Sips models. Indirect thermodynamic determinations have indicated that the sorption of Cr(VI)
is endothermic (ΔH = 31,21 kJ mol-1), spontaneous (ΔG < 0), with positive entropies (ΔS = 0,14 kJ mol-1 K-1). Calorimetric measurements have suggested that the interactions of Cr (VI) with the surface sorption sites of Corvina scales are exothermic in nature. It also was found that the presence of an anionic surfactant can increase Cr(VI) sorption on Corvina scales due to a dynamic equilibrium between monomers and micelles. The initial analysis of Cr(VI) desorption from Corvina scales has shown the release of about 30% of sorbed chromium in alkaline medium. It has been noted that the scales of Corvina fish present important characteristics to
be used as a new adsorbent for removal of Cr(VI) from aqueous solutions. / A sorção tem se tornado um método muito atrativo, pois permite extrair compostos tóxicos em níveis muito baixos e não gerar subprodutos tóxicos em efluentes aquosos. O presente trabalho avaliou a utilização de
escamas de peixe Corvina (Micropogonias furnieri) como um novo adsorvente para remoção do Cr(VI) de soluções aquosas. As escamas foram caracterizadas por termogravimetria, espectroscopia na região do infravermelho, microscopia eletrônica de varredura com medidas de energia dispersiva, difratometria de raios-X e determinação do pH do ponto de carga zero. Os resultados indicaram que as escamas são formadas, predominantemente, de uma fase orgânica rica em colágeno tipo I e outra rica em apatitas. Testes calorimétricos de molhação das escamas apontaram energias de molhação exotérmicas e graus de molhação entre 30,8-45,3%. Estudos cinéticos mostraram aumento da capacidade de remoção das escamas com o aumento da concentração inicial de Cr(VI) em solução e da temperatura. Estudos de cinética de sorção de Cr(VI) por batelada e por calorimetria em solução apontaram melhores ajustes matemáticos utilizando-se o modelo exponencial de Avrami. Estudos de sorção no equilíbrio indicaram melhor ajustes aos modelos de Langmuir-Freundlich e Sips. Determinações termodinâmicas indiretas indicaram que os processos de sorção são endotérmicos (ΔH = 31,21 kJ mol-1), espontâneos (ΔG < 0), e com aumento de entropia após os processos de sorção (ΔS = 0,14 kJ mol-1 K-1). Medidas calorimétricas
em solução indicaram que as interações de Cr(VI) com os sítios de sorção mais externos são processos exotérmicos. A presença de surfactante aniônico na solução de Cr(VI) pode aumentar a sorção de Cr(VI) pelas
escamas devido a um equilíbrio dinâmico entre monômeros e micelas. Testes iniciais de dessorção de Cr(VI) indicaram liberação de cerca de 30% do crômio sorvido, em meio básico. Observou-se que as escamas de
Corvina apresentam excelentes perspectivas como um novo material para remoção de Cr(VI) de soluções aquosas.
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Comportamento de corrosão de camadas isentas de cromo hexavalente e sem enxágue aplicadas sobre superfícies eletrozincadas produzidas em linhas contínuas. / Corrosion behavior of layers free hexavalent chromium no rinse applied on eletrozincs surfaces produced in lines continuing.Victor Ernesto Pérez Hernández 15 December 2014 (has links)
A preocupação com o desenvolvimento sustentável tem levado a indústria e os órgãos controladores do meio ambiente a reavaliarem o emprego em larga escala de procedimentos industriais que, embora eficientes, são prejudiciais à saúde humana e ao meio ambiente. Em concordância com estas novas tendências, as indústrias de tratamento de superfícies de metais e instituições de pesquisa têm empregado grandes esforços no sentido de encontrar substitutos eficientes para procedimentos de proteção contra a corrosão que contenham íons de cromo hexavalente, os quais são muito eficientes, mas apresentam o inconveniente de não serem ambientalmente corretos devido ao caráter cancerígeno e poluente do íon Cr(VI) já reconhecido por diversas agências de proteção ambiental. Com a finalidade de aumentar a proteção contra a corrosão, em linhas industriais contínuas de eletrogalvanização por eletrodeposição, as peças produzidas são protegidas por uma camada de passivação obtida em banho de conversão contendo sais de Cr(VI) e, na maioria dos casos, não passa pelo processo de enxágue após sua produção. Neste trabalho o comportamento de corrosão do aço eletrogalvanizado protegido com camadas de passivação obtidas a partir de banhos de conversão contendo sais de Cr(III) e Co(II) ou uma emulsão de um copolímero de etileno, sem enxágue, foi avaliado por técnicas eletroquímicas, especificamente, acompanhamento do potencial de circuito aberto, curvas de polarização potenciodinâmica anódicas e catódicas, e espectroscopia de impedância eletroquímica (EIS), em soluções com diferentes concentrações de NaCl. Adicionalmente foi avaliado o comportamento de corrosão por ensaios em câmara de névoa salina, realizados de acordo com a norma ASTM B117-11. Como referência, os resultados foram comparados com aqueles apresentados por amostras protegidas por camada de passivação produzida a partir de banho contendo íons de Cr(VI). Para melhor compreender a influência da microestrutura sobre o mecanismo de corrosão, as amostras foram caracterizadas por microscopia eletrônica de varredura antes e após imersão nos diferentes eletrólitos. A análise microestrutural foi complementada por ensaios de difração de raios-X. 7 Os resultados dos ensaios eletroquímicos realizados após tempos curtos de imersão mostraram melhor desempenho para as amostras protegidas com a camada de passivação produzida a partir de banho contendo íons Cr(VI). Entretanto os ensaios de EIS após tempos mais longos de imersão nos diferentes eletrólitos ensaio, bem como os ensaios de névoa, evidenciaram que as amostras protegidas com a camada passiva obtida a partir do banho contendo íons de Cr(III) e Co(II) podem apresentar desempenho semelhante àquelas protegidas com camada de conversão de Cr(VI). Para esta condição, a análise microestrutural e o ajuste dos diagramas de EIS com circuitos equivalentes indicaram um papel importante dos produtos de corrosão no comportamento anticorrosivo das amostras protegidas com a camada de passivação de Cr(III) e Co(II). Em nenhuma das condições estudadas as amostras protegidas com o copolímero de etileno apresentaram desempenhos comparáveis aos das outras duas camadas de passivação estudadas. / Recent concerns with sustainable development have led industries and environment regulatory agencies to reassess the use at large scale of industrial procedures that, although efficient, are harmful to human health and the environment. In accordance with these new tendencies, surface treatment industries and research institutes have expended great efforts to find efficient substitutes for corrosion protection procedures that employ hexavalent chromium ions (Cr(VI)). They are very effective but have the drawback of not being environmentally friendly due to the carcinogenic and pollutant properties of Cr(VI) ions, already recognized by several environmental protection agencies. Aiming to increase the corrosion protection, in industrial continuous lines of galvanizing by electroplating, the parts produced are protected with a passivation layer obtained from a conversion bath containing Cr(VI). These parts are not rinsed after the final production step. In this work the corrosion behavior of electroplated galvanized steel protected with passivation layers from conversion baths containing Cr(III) and Co(II) ions or an ethylene copolymer emulsion was evaluated by means of electrochemical techniques, specifically, open circuit potential measurements, anodic and cathodic potentiodynamic polarization curves and electrochemical impedance spectroscopy (EIS). The tests were performed in sodium chloride solutions of different concentrations. Additionally, the corrosion behavior was evaluated by salt spray tests performed according the ASTM B117-11 standard. For reference, the results were compared with those presented by samples protected by passivation layers produced from conversion baths containing Cr (VI) ions. Aiming to better understand the influence of microstructure on the corrosion mechanism, the samples were characterized by scanning electron microscopy before and after immersion in the different electrolytes. Microstructure analysis was complemented by X-ray diffraction. The results of electrochemical tests performed after short immersion times showed better corrosion performance for samples protected with the passivation layer produced from conversion baths containing Cr(VI) ions. However, the EIS tests performed after longer immersion times in the different electrolytes, as well as the 9 salt spray tests, showed that samples protected with the passive layer obtained from the bath containing Cr (III) and Co (II) ions may present similar performance to those protected with the Cr (VI) conversion layer. The microstructural analysis and fitting of the EIS diagrams with equivalent circuits indicated an important role of corrosion products in the anti-corrosive performance of the samples protected with the passivation layer of Cr (III) and Co (II). In the studied conditions, the samples protected with the ethylene copolymer did not showed comparable performance to the other two passivation layers investigated in the present study.
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Type VI secretion system effectorsLe, Thi Thu Hang 22 February 2017 (has links)
Mon travail a porté sur la caractérisation des effecteurs toxiques et protéines d’immunité du T6SS Sci-1 d’Escherichia coli Entero-agrégatif, éléments de la lutte inter-bactérienne. Nous avons identifié en outre Tle1, un effecteur de toxine codé par ce groupe et montré que Tle1 possède des activités de phospholipase A1 et A2 requises pour détruire la cellule proie dans la compétition interbactérienne. L'auto-protection de la cellule attaquante est assurée par une lipoprotéine de membrane externe, Tli1, qui lie Tle1 dans un rapport stoechiométrique 1: 1 avec une affinité nanomolaire et inhibe son activité phospholipase. Il a été prédit que la protéine 435 provenant à partir d'un groupe de gènes T6SS1 de l'agent pathogène AIEC LF82 est une phospholipase de la famille d'effecteurs Tle3 avec une activité PLA1. Sa toxicité peut être neutralisée par la protéine d'immunité cognate 434 qui est un Tli3 putatif, en formant le complexe de protéine Tle3 - Tli3. Les deux protéines séparées et leur complexe ont ensuite été appelées protéines complexes Tle3AIEC, Tli3AIEC et Tle3AIEC - Tli3AIEC, respectivement. Afin d'étudier plus en détail le mécanisme de Tle3-AIEC et de Tli3-AIEC, nous avons réalisé l'expression, la purification, la caractérisation, la cristallisation des deux protéines et des études cristallographiques de rayons X préliminaires du complexe Tle3-AIEC/Tli3-AIEC afin de comprendre comment la protéine Tle3-AIEC reconnaît et se lie à son effecteur apparenté Tli3-AIEC et inhibe son activité. Les données préliminaires de diffraction des rayons X ont été recueillies à partir de cristaux Tle3AIEC-SeMet/Tli3AIEC à une résolution de 3,8 Å. / Here, we analyzed the Entero-aggregative Escherichia coli Sci-1 T6SS toxin effectors. We identified Tle1, a toxin effector encoded by this cluster and show that Tle1 possesses phospholipase A1 and A2 activities required for the inter-bacterial competition. Self-protection of the attacker cell is secured by an outer membrane lipoprotein, Tli1, which binds Tle1 in a 1:1 stoichiometric ratio with nanomolar affinity, and inhibits its phospholipase activity.The protein 435 from the pathogen AIEC LF82 has been predicted to be a phospholipase of the Tle3 effector family with PLA1 activity from a T6SS1 gene cluster. Its toxicity can be neutralized by the cognate immunity protein 434 that is a putative Tli3, by forming Tle3 - Tli3 protein complex. The two separated proteins and their complex were then called Tle3AIEC, Tli3AIEC and Tle3AIEC - Tli3AIEC complex proteins, respectively. In order to further investigate the related mechanism of Tle3AIEC and Tli3AIEC, we performed expression, purification, characterization, crystallization of the two proteins and preliminary X-ray crystallographic studies of the Tle3AIEC - Tli3AIEC complex in order to understand how Tle3AIEC protein recognizes and binds to its cognate Tli3AIEC effector and inhibits its activity. X-ray diffraction data were collected from selenomethionine-derivatize Tle3AIEC SeMet - Tli3AIEC crystals to a resolution of 3.8 Å.
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Unga vuxna som varken arbetar eller studerar : Inifrånperspektiv om vägar till sysselsättning / Young adults who neither work nor study : Inside perspective on pathways to employmentFernström, David, Carlsson, Julia January 2020 (has links)
The purpose of this study has been to explore and provide the social work field with testimonies about experienced factors of success using interviews with people who previously were not in education, employment or training (NEET). NEETs were classified into five categories to identify themes in their experienced factors of success. This process was made through thematic analysis. The experienced factors of success were thematized into major themes. The expressed themes followed the person to whom it belonged into their respective NEET-category. Categories and themes were analyzed with Bronfenbrenner’s ecological systems theory. Through this analysis we found indications that different NEET-categories have different needs. This could be an indication that categorization can shed some clarity in the NEET phenomena. Viewing NEET as categories with specific needs provides homogeneity which could accelerate the social services process of identifying and providing appropriate help. Though specific needs of individual NEET-categories need further investigation to become effective. / VI-projektet
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Vatikán a Československo v roce 1968 / Vatican and Czechoslovakia in 1968Nedvěd, René January 2021 (has links)
The thesis deals with the Czechoslovakia - Vatican relationships in the 1960's with an emphasis on the 1968 Prague Spring time. It summarises the importance of the 2nd Ecumenical Council of the Vatican and demonstrates the transformation of the papacy starting with early 1960's. The core of the thesis is an analysis of the political relations between Czechoslovakia and Vatican in 1968, and the attitude of Pope Saint Paul VI. (1963-1978) to the events in Czechoslovakia, with added emphasis on the personalities of Czech and Slovak bishops, negotiations between the Church and the state, as well as the metamorphoses of the Czechoslovakia-Vatican diplomatic contacts. The diplomatic negotiations present an interesting bonus primarily from the Radio Vaticana archive, which is available, in a digital version, at the Institute for the Study of Totalitarian Regimes website. Keywords Communism; Vatican II - Second Ecumenical Council of the Vatican; Pope St. Paul VI.; Catholic Church; Vatican.
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Entwicklung und Validierung mathematischer Methoden zur Auswertung spektroskopischer Daten der Uranyl(VI)-HydrolyseDrobot, Björn 18 August 2016 (has links)
Die Verfügbarkeit von Metallen in der Geo- und Biosphäre wird durch deren chemische Form, die Speziation, bestimmt. Zur Analyse der Speziation gibt es eine Vielzahl von Techniken. Für spektroskopische Methoden sind untersuchbare Konzentrationsbereiche unter anderem durch entsprechende Detektionsgrenzen eingeschränkt. Vor allem für niedrige Konzentrationen (< 10 µM), wie sie für viele natürliche Systeme von Bedeutung sind, ist die Lumineszenzspektroskopie ein geeignetes Werkzeug.
Die Zerlegung spektroskopischer Daten von komplexen Systemen stellt eine zusätzliche Herausforderung dar. Zur Extraktion spektraler Informationen individueller chemischer Spezies werden moderne mathematische Verfahren verwendet. Die so erhaltene spektroskopische Charakterisierung kann zur strukturellen und thermodynamischen Interpretation genutzt werden.
In dieser Arbeit wurde die parallele Faktoranalyse (PARAFAC) zur Auswertung spektroskopischer Datensätze genutzt. Diese Technik wurde hier erstmals auf Uranyl(VI)-Systeme angewendet, wodurch eine umfassende lumineszenzspektroskopische Charakterisierung der Uranyl(VI)-Hydrolyse generiert wurde.
Zusätzlich wurde der bestehende PARAFAC-Algorithmus (N-way Toolbox) erweitert. Damit wird die Zerlegung auf chemisch interpretierbare Ergebnisse beschränkt und eine direkte Extraktion thermodynamischer Daten ermöglicht. Für die mononuklearen Hydrolysespezies konnten korrigierte Komplexstabilitätskonstanten vorgeschlagen werden, wodurch entsprechende Speziationsrechnungen belastbarer werden.
Die extrahierten spektralen Eigenschaften einzelner Spezies wurden anschließend sorgfältig analysiert. Dazu wurden quantenmechanische sowie semiempirische Ansätze genutzt. Neben einerValidierung der angenommenen Speziesbezeichnung wurde dadurch erstmals eine fundierte lumineszenzspektroskopische Signal-Struktur-Beziehung für die Uranyl(VI)-Hydrolyse generiert.
Die entwickelten Algorithmen wurden im Rahmen der Arbeit auf komplexere Systeme des Uranyl(VI) und Europium(III) übertragen und deren Gültigkeit nachgewiesen. So konnten neue Erkenntnisse zur Lumineszenzlöschung des Uranyl(VI)-Ions und der Europium(III)-Hydrolyse gewonnen werden. Zudem wurde eine Strategie zur einfachen und akkuraten Bestimmung der Anzahl von Bindungsstellen am Beispiel des Proteins Calmodulin vorgestellt. Der aufgezeigte breite Anwendungsbereich wird zusätzlich durch die erfolgreiche Übertragung der SpecConst-Erweiterung auf andere spektroskopische Techniken (am Beispiel der UV-vis Spektroskopie) erweitert. Die vorgestellten Werkzeuge verbessern die Auswertung spektroskopischer Daten und erweitern das damit verbundene Verständnis komplexer umweltrelevanter Systeme.:Danksagung I
Abkürzungen IV
1 Motivation 1
2 Einleitung und Hintergrund 4
2.1 Speziation 4
2.1.1 Hydrolyse 6
2.2 Uran 7
2.2.1 Uranyl(VI) 13
2.3 Optische Spektroskopie 14
2.3.1 Absorptionsspektroskopie 15
2.3.2 Lumineszenz 16
2.3.3 Uranyl(VI)-Lumineszenz 18
3 Material und Methoden 24
3.1 Chemikalien 24
3.2 Komplexbezeichnung 25
3.3 Probenvorbereitung 26
3.4 Absorptionsspektroskopie 27
3.5 Lumineszenzspektroskopie 27
3.5.1 Continuous Wave Spektroskopie 27
3.5.2 Zeitaufgelöste laserinduzierte Fluoreszenzspektroskopie 30
3.6 Datenauswertung - PARAFAC 34
3.7 Extrapolation auf Standardbedingungen 38
4 Ergebnisse und Diskussion 40
4.1 Methodenentwicklung 40
4.1.1 Exponentielle Einschränkung für PARAFAC - ’ExpConst’ 40
4.1.2 Speziationseinschränkung für PARAFAC - ’SpecConst’ 42
4.1.3 Spektrenzerlegung 45
4.2 Validierung der Methoden am Beispiel der Uranyl(VI)-Hydrolyse 51
4.2.1 Hydrolyse von 10−5 M Uranyl(VI) 51
4.2.2 Hydrolyse von 10−8 M Uranyl(VI) 62
4.2.3 Absorptionsspektroskopie der Uranyl(VI)-Hydrolyse 72
4.3 Übertragung der Methoden auf komplexere Uranyl(VI)-Systeme 75
4.3.1 Das Uranyl(VI)-Carbonat-System 75
4.3.2 Das Uranyl(VI)-Halogenid-System 79
4.4 Übertragung der Methoden auf Europium(III)-Systeme 86
4.4.1 Die Europium(III)-Hydrolyse 86
4.4.2 Interaktion von Europium(III) mit Calmodulin 94
5 Zusammenfassung 103
Literaturverzeichnis 106
Abbildungsverzeichnis 131
Tabellenverzeichnis 134
Publikationen im Rahmen dieser Arbeit i
Konferenzbeiträge iii
Eidesstattliche Erklärung iv
Versicherung v
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Étude de nanostructures de semiconducteurs II-VI par sonde atomique tomographique / Study of II-VI semiconductors nanostrures by atom probe tomographyBenallali, Hammouda 08 April 2015 (has links)
Les nanostructures de semiconducteurs II-VI ont de nombreuses applications en microélectronique, optoélectronique et photonique. Notamment, les boites quantiques II-V peuvent servir de source de photons uniques. Dans cette étude, nous nous sommes intéressés à la caractérisation chimique et structurale des nanostructures de semiconducteurs II-VI (boites quantiques (BQs) auto-organisées, nanofils II-VI et III-V …) par sonde atomique tomographique (SAT). Dans un premier temps, nous avons optimisé les conditions d’analyse des semiconducteurs III-V et II-VI par SAT. Ensuite, nous avons étudié les compositions chimiques des interfaces II-VI/III-V en montrant la formation d’un composé Ga2.7Se3 à l’interface ZnSe/GaAs et un mélange de cations (Ga, Zn) à l’interface ZnTe/InAs. Les mesures de compositions chimiques et des tailles des boites quantiques en trois dimensions par SAT ont permis de faire une corrélation avec les mesures optiques. Nous nous sommes aussi intéressés à l’étude des mécanismes de croissance des nanofils GaAs et ZnTe ainsi que des BQs (CdTe) insérés dans des nanofils ZnTe en analysant la composition chimique des catalyseurs, les BQs dans les nanofils aussi que la base des nanofils. Ces mesures montrent que les boites quantiques sont formées d’un fort mélange CdxZn1-xTe. Un scénario basé sur la diffusion de surface a été proposé pour expliquer la croissance ainsi que le mélange entre Zn/Cd pour les BQs insérées dans les nanofils. / Nanostructures of II-VI nanostructure have many applications in microelectronics, optoelectronics and photonics. For example, II -V quantum dots have shown the ability to be a source of single photons. In this work, we performed in the chemical and structural characterization of nanostructures of II-VI semiconductors (self- organized quantum dots (QDs), nanowires II-VI and III- V ...) by atom probe tomography (APT). Firstly, the analysis conditions of III-V and II- VI semiconductors by APT were optimized. Then, we studied the chemical composition of II-VI/III-V interfaces and showed the formation of a Ga2.7Se3 compound at the ZnSe/GaAs interface and the (Ga, Zn) cations mixing at the ZnTe/InAs interface. The measurements of the chemical composition and the sizes of quantum dots in three dimensions by APT allowed making a correlation with optical measurements. We studied also growth mechanisms of GaAs, ZnTe nanowire and the CdTe QDs inserted in ZnTe nanowires by analyzing the chemical composition of the catalysts QDs and nanowires basis. These measurements show that the quantum dots are formed of a strong mixing of CdxZn1-xTe. A scenario based on surface diffusion has been proposed to explain the growth and the mixing between Zn/Cd for the QDs.
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