Made available in DSpace on 2014-06-11T19:27:25Z (GMT). No. of bitstreams: 0 Previous issue date: 2004-04-26Bitstream added on 2014-06-13T18:56:11Z : No. of bitstreams: 1 campos_a_me_rcla.pdf: 4152569 bytes, checksum: 41a529d2c0be5a0a79eb44e0ec1448ea (MD5) / Os plasticos constituem um dos materiais mais utilizados em nosso cotidiano. Assim, os residuos plasticos tem aumentado bastante e hoje representam 20% do total do volume de residuos, em lixoes municipais. O PVC (policloreto de vinila) e um polimero sintetico, instavel em relacao ao calor e luz, que degrada a temperatura relativamente baixa (aproximadamente 130oC), e libera HCl. A desidrocloracao gera novas especies na cadeia polimerica, ou seja, sequencias de polienos que podem ser verificadas atraves da espectroscopia de absorcao na faixa do UV-Visivel. A reciclagem do PVC apresenta algumas dificuldades intrinsecas ao comportamento do polimero, durante o processo tecnologico e, alem disso, sua biodegradacao e dificil. O PCL (poli α-caprolactona), um poliester sintetico, e sensivel a acao de enzimas microbianas, e pode sofrer hidrolise e degradacao. A mistura desses polimeros, isto e, a blenda de PVC e PCL pode constituir um meio para facilitar o ataque microbiano ao PVC, alem de melhorar ou manter as propriedades mecanicas da blenda. Processos termo e fotodegradativos podem facilitar o ataque microbiano a matriz polimerica do PVC. O presente trabalho pretende investigar a termo, foto e biotransformacao de filmes de blendas de PVC/PCL 1:1 e 3:1 com fungos de solo (Phanerochaete chrysosporium e Aspergillus fumigatus). As mudancas estruturais foram analisadas atraves da espectroscopia de absorcao no infravermelho (FTIR) e no UV-Visivel e as mudancas morfologicas, atraves de Microscopia Eletronica de Varredura (MEV) / The plastics are one of used the most materials daily. Thus, the plastics wastes have increased considerably and today represent 20% of the waste total volume in the municipal landfills. PVC (poly vinyl chloride) is a synthetic polymer, unstable in the presence of heat and light, that degrades on relative low temperature (approximately 130ºC), and releases HCl. The dehydrochlorination produces new species on polymeric chain, thus, polyenes sequences, that can be checked by the UV-Visible absorption spectroscopy. The recycling of PVC presents some difficulties due its behaviour during the technological processing and its biodegradation is difficult. PCL (polycaprolactone), a synthetic polyester is susceptible to enzymes action, and undergo hydrolysis and degradation. The blend of PVC and PCL can be one way to facilitate the microorganisms attack to the PVC polymer and to improve the mechanical properties of the blend. Thermal and photodegradation process can to facilite the microorganisms attack on PVC polymeric chain. The present work intends to investigate the thermal, photo and biotransformation of polymer films and blends of PVC/PCL 1:1 and 3:1 blends, with soil fungi (Phanerochaete chrysosporium and Aspergillus fumigatus). The structural changes were analysed by infrared absorption spectroscopy (FTIR) and the UV-Visible. The morphologics changes were investigated by scanning electron microscopy (SEM)

Made available in DSpace on 2014-06-12T16:29:46Z (GMT). No. of bitstreams: 2 arquivo2743_1.pdf: 2012890 bytes, checksum: 990d95aa03c535d23d043c7880f92539 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2011 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / A espectrofotometria no ultravioleta-visível (UV/Vis) e a cromatografia líquida de alta eficiência (CLAE) destacam-se dentre os métodos analíticos empregados para quantificação de flavonóides em drogas vegetais. Entretanto, questionamentos sobre a especificidade e equiparação de seus resultados vem sendo suscitados diante das características e limitações de cada técnica. Dessa forma, o objetivo principal deste trabalho foi avaliar comparativamente a CLAE e metodologias espectrofotométricas para quantificação de flavonóides em folhas de Bauhinia forficata Link (pata de vaca), com o intuito de estabelecer especificações analíticas que permitam que as técnicas possam ser empregadas alternativamente. Buscou-se também estabelecer especificações para o controle de qualidade da espécie escolhida, por meio de amostras do material vegetal, obtidas de duas regiões do Brasil, que foram submetidas à caracterização fitoquímica e físicoquímica (granulometria, perda por dessecação, teor de cinzas e teor de extrativos). Para a avaliação dos métodos analíticos, foram desenvolvidas e validadas, segundo o ICH e RE nº 899/03 (ANVISA), técnicas espectrofotométricas para quantificação de flavonóides totais, uma por diluição direta e outra por hidrólise ácida, e uma metodologia por CLAE para quantificação do marcador canferitrina. As respostas encontradas para três níveis de concentração foram avaliadas estatisticamente. Observou-se para as duas amostras um perfil fitoquímico similar, apresentando: flavonóides, proantocianidinas, leucoantocianidinas, triterpenos e esteróides. Constatou-se que o tamanho de partícula e a umidade residual mostraram-se divergentes em virtude da origem e do processamento adotados pelos fornecedores. Sendo que os valores do teor de cinzas mostraram-se dentro das especificações e não foi observada diferença significativa para o teor de extrativos. As metodologias desenvolvidas mostraram-se específicas, sensíveis, precisas, exatas e robustas, sendo adequadas para as análises realizadas. As amostras de B. forficata mostraram resultados similares para os dois procedimentos espectrofotométricos, porém apenas uma delas apresentou canferitrina. Por isso, questiona-se a adoção desse constituinte como marcador apropriado para a espécie, haja vista que pode comprometer o emprego de CLAE como ferramenta analítica. Por outro lado, considerando que a canferitrina apresenta as propriedades físico-químicas de seu grupo de metabólitos, sua ausência em uma das amostras não invalida a avaliação do desempenho dos métodos, pois a observação de desempenho similar para o método seletivo (CLAE) e o método para quantificação de grupos, pode conferir maior confiabilidade a técnica geral e sugere comportamento similar para compostos estruturalmente semelhantes. Portanto, o estudo comparativo foi conduzido apenas com a amostra contendo canferitrina e permitiu estabelecer correlação positiva e ausência de erros sistemáticos significativos entre todos os procedimentos, indicando que os mesmos podem ser utilizados alternativamente sem que haja prejuízo de suas respostas. Dessa forma, considerando ainda a simplicidade, baixo custo de execução e variabilidade intrínseca da matriz em questão, a adoção das técnicas espectrofotométricas permanecem como alternativas válidas para análise de flavonóides em folhas de B. Forficata. Por fim, os resultados obtidos neste trabalho contribuíram no processo de identificação e padronização de parâmetros de qualidade para a planta supracitada

Made available in DSpace on 2014-06-12T23:13:19Z (GMT). No. of bitstreams: 2 arquivo2643_1.pdf: 948572 bytes, checksum: fdfaa21b513d1dab3602059ce3b208f5 (MD5) license.txt: 1748 bytes, checksum: 8a4605be74aa9ea9d79846c1fba20a33 (MD5) Previous issue date: 2009 / Conselho Nacional de Desenvolvimento Científico e Tecnológico / Filmes coloridos à base de poli(metacrilato de metila) (PMMA) foram preparados com a finalidade de obtenção de dosímetros plásticos para atender as necessidades do mercado nacional. Neste projeto, os corantes azul de bromotimol (AB) e vermelho fenol (VF), em diferentes concentrações, foram utilizados na formulação dos sistemas poliméricos dosimétricos PMMA/AB e PMMA/VF, respectivamente. Estes sistemas têm características dosimétricas com aplicações industriais em áreas de radioesterilização de artefatos médicos e alimentos. A resposta dosimétrica (absorbância) dos sistemas mostrou boa correlação linear (R2 > 0,95) no intervalo de doses de 5 100 kGy (sistema PMMA/AB, λ = 403nm) e 2 25 kGy (sistema PMMA/VF, λ = 406nm). Foram investigadas também a dependência da resposta com a taxa de dose dos sistemas nas taxas de 8,148 kGy/h e 4,074 kGy/h, assim como a estabilidade da resposta com o tempo de armazenamento em diferentes condições de temperatura e exposição à luz fluorescente. Os resultados mostram que ambos os sistemas, PMMA/AB e PMMA/VF, apresentam boa estabilidade quando os filmes são armazenados à temperatura de ~10°C, protegidos da luz fluorescente antes e após a irradiação durante 60 dias (sistema PMMA/AB) e 80 dias (sistema PMMA/VF). Entretanto, estes sistemas apresentam dependência com a taxa de dose, sendo necessária a utilização de curvas de calibração únicas para cada taxa de dose

Pesticide testing is of practical interest in various areas of today’s world due to their prevalence and toxicity. These areas include agriculture, environmental, chemical plants, and many others. Herbicides, like Roundup, contain secondary amines such as glyphosate. The ability to detect secondary amines could offer a method for glyphosate detection in agricultural and environmental samples. Secondary amines can interact with metal complexes through electron charge transfer. Such interactions can cause a change in the metal’s electron configuration and energy state and can be seen in the UV-Vis spectrum. Metal phthalocyanines (MPc’s) and other organometallic complexes have been of interest for these reasons and may be applicable to glyphosate detection without extensive laboratory tests. UV-Vis absorption can further provide quantitative measurements. An evaluation of FeTSPc’s ability to aid in remediation via adsorption supports was also examined.

Synthetische anorganische Knochenersatzmaterialien auf Calcium-Phosphat- und Magnesium-Phosphat-Basis wurden in der hier vorliegenden Dissertation mit verschiedenen handelsüblichen Antibiotika versetzt und deren Freisetzungsverhalten charakterisiert. Zudem wurde der Einfluss des Antibiotikazusatzes auf bestimmte materialcharakteristische Eigenschaften untersucht, hierbei fanden die Quecksilberporosimetrie, die Röntgendiffraktometrie und die Rasterelektronenmikroskopie ihre Anwendung. Insbesondere für die Knochenersatzmaterialien auf Calcium-Phosphat-Basis sollte eine klinisch praktikable und demnach möglichst einfache Methode etabliert werden, um die Kombination mit einem Antibiotikum durchzuführen. Die Detektion der Antibiotika erfolgte mit Hilfe eines UV/VIS-Spektrophotometers. Zudem wurde für einige ausgewählte Kombinationen aus Antibiotikum und Knochenersatzmaterial durch einen Agardiffusionstest die antibakterielle Wirkung nach der Freisetzung aus dem jeweiligen Trägermaterial bestätigt. / Synthetic inorganic bone substitute materials based on calcium phosphate and magnesium phosphate were mixed with various commercially available antibiotics and their release behavior was characterized in the present dissertation. In addition, the influence of the antibiotic addition on certain material characteristic properties was investigated using mercury porosimetry, X-ray diffractometry and scanning electron microscopy. For the calcium-phosphate-based bone substitutes in particular, the aim was to establish a clinically practicable and therefore as simple as possible method for carrying out the combination with an antibiotic. Antibiotics were detected using a UV/VIS spectrophotometer. In addition, for some selected combinations of antibiotic and bone substitute material, an agar diffusion test was used to confirm the antibacterial effect after release from the respective carrier material.

This publication is dedicated to investigate strong light-matter coupling with excitons in 2D materials. This work starts with an introduction to the fundamentals of excitons in 2D materials, microcavities and strong coupling in chapter 2. The experimental methods used in this work are explained in detail in chapter 3. Chapter 4 covers basic investigations that help to select appropriate materials and cavities for the following experiments. In chapter 5, results on the formation of exciton-polaritons in various materials and cavity designs are presented. Chapter 6 covers studies on the spin-valley properties of exciton-polaritons including effects such as valley polarization, valley coherence and valley-dependent polariton propagation. Finally, the formation of hybrid-polaritons and their condensation are presented in chapter 7. / Diese Veröffentlichung beschäftigt sich mit starker Licht-Materie Kopplung mit Exzitonen in 2D Materialien. Dies Arbeit beginnt mit einer Einführung in Exzitonen in 2D Materialien, in Mikrokavitäten und starke Licht-Materie Kopplung (Kapitel 1). Die verwendeten, experimentellen Methoden werden in Kapitel 3 beschrieben. Kapitel 4 deckt Voruntersuchungen ab, die helfen die richtigen Materialien und Mikrokavitäten für die folgenden Experimente auszuwählen. In Kapitel 5 werden die Ergebnisse zur Erzeugung von Exziton-Polaritonen in verschiednen Materialen und Kavitäten gezeigt. Kapitel 6 beschäftigt sich mit Untersuchungen der Spin-Tal Eigenschaften der Exziton-Polaritonen, inkl. Effekte wie Tal Polarisation und Koherenz. Abschließend wird in Kapitel 7 die Erzeugung von Hybrid-Polaritonen und deren Kondensation dargestellt.

The continuously increasing demand for innovation in the miniaturization of microelectronics has driven the need for ever more precise fabrication strategies for device packaging, especially for printed circuit boards (PCBs). Subtractive copper etching is a fundamental step in the fabrication process, requiring very precise control of etch rate and etch factor. Changes in the etching chemical equilibrium have significant effects on etching behavior, and CuCl2 / HCl etching baths are typically monitored with several parameters including oxidation-reduction potential, conductivity, and specific gravity. However, the etch rate and etch factor can be difficult to control even under strict engineering controls of those monitoring parameters. The mechanism of acidic cupric chloride etching, regeneration and recovery is complex, and the current monitoring strategies can have difficulty controlling the interlocking chemical equilibria. A complimentary tool, thin-film UV-Vis spectroscopy, can be utilized to improve the current monitoring strategies, as UV-Vis is capable of identifying and predicting etching behavior that the current standard methodologies have difficulty predicting. Furthermore, as a chemically-sensitive probe, UV-Vis can investigate the complex changes to the chemical equilibrium and speciation of the etch bath, and can contribute overall to significant improvements in the control of the copper etching system in order to meet the demands of next-level design strategies.

Magnetite, an iron oxide, is a possible candidate for in situ remediation of contaminated groundwater systems due to its oxidation/reduction potential for reduction of contaminants such as carbon tetrachloride. Little characterization and analysis has been done to describe the kinetics of magnetite transformation during oxidation. This work focuses on monitoring the concentrations of magnetite and one of its oxidation transformation products, maghemite, by the use of UV-Vis-NIR spectroscopy. As oxidation proceeded at a constant specific temperature, the concentration of magnetite decreases, which was indicated by a decrease in absorption in the NIR-region of the spectrum. As magnetite concentrations decreased, the concentration of maghemite increased, which was indicated by an increase in absorption in the UV-region. The temperature at which the suspensions of magnetite and maghemite were measured was of great importance for complete understanding of the magnetite transformation as seen by UV-Vis-NIR spectroscopy analysis. Higher measurement temperatures produced higher absorptivities of FeII-FeIII electron hopping transitions, while decreasing the absorptivity of FeIII-FeIII in the NIR and UV-regions respectively. Lower temperatures produced the opposite effects on the iron oxides' transitions. Higher temperature increased the rate of oxidation. / Master of Science

2-Nitrobenzanthron (2-NBA) and 3-nitrobenzanthron (3-NBA) are pollutants widely occurring in the environment. The main sources of benzanthrones are combustion products (i.e. diesel exhausts, wood and cigarette smoke ...). 3-NBA is proven strong mutagen and carcinogen for bacteria and mammals and it is probably mutagenic also to humans, while 2- NBA shows genotoxic properties lower by 3-4 orders of magnitude. Here we consider the possibility that large difference in the solubility, and consequently also the difference in bioavailability of these isomers could be the factor partially explaining this phenomenon. One goal was to determine solubility of 2-NBA in water and compare it with 3-NBA and also with other carcinogens studied in our laboratory (Sudan I, ellipticin). Another objective was to evaluate the effect of model proteins (bovine serum albumin, lysozyme) on solubility of Sudan I and ellipticine. The last aim was to determine extinction coefficients of these compounds in water and in methanol. Two different methods were employed to determine the solubility of the model compounds. The first method was based on spectrophotometric verification of the Lambert- Beer law. The results were than compared with other method measuring concentration of a compound in saturated solution (In Czech) Key...

2-Nitrobenzanthron (2-NBA) and 3-nitrobenzanthron (3-NBA) are pollutants widely occurring in the environment. The main sources of benzanthrones are combustion products (i.e. diesel exhausts, wood and cigarette smoke ...). 3-NBA is proven strong mutagen and carcinogen for bacteria and mammals and it is probably mutagenic also to humans, while 2- NBA shows genotoxic properties lower by 3-4 orders of magnitude. Here we consider the possibility that large difference in the solubility, and consequently also the difference in bioavailability of these isomers could be the factor partially explaining this phenomenon. One of our goals was to determine the solubility of 2-NBA in water and compare it with 3-NBA and also with other carcinogens studied in our laboratory (Sudan I, ellipticin). The second aim was to determine extinction coefficients of these compounds in water and in methanol. Two different methods were employed to determine the solubility of the model compounds. The first method was based on spectrophotometric verification of the Lambert- Beer law. The results were than compared with other method utilizing determination of concentration of a compound in equilibrium with solid phase. (In Czech) Key words: solubility, UV-VIS spectroscopy, 3-nitrobenzanthrone, 2-nitrobenzanthrone, ellipticine, Sudan I