No description available.

The goal of this thesis is the development of scalable, low cost synthesis of metal oxide nanostructures based electrodes and to correlate the chemical modifications with their energy conversion performance. Methods in energy conversion in this thesis have focused on two aspects; a potentiometric chemical sensor was used to determine the analytical concentration of some components of the analyte solution such as dopamine, glucose and glutamate molecules. The second aspect is to fabricate a photo-electrochemical (PEC) cell. The biocompatibility, excellent electro-catalytic activities and fast electron transfer kinetics accompanied with a high surface area to volume ratio; are properties of some metal oxide nanostructures that of a potential for their use in energy conversion. Furthermore, metal oxide nanostructures based electrode can effectively be improved by the physical or a chemical modification of electrode surface. Among these metal oxide nanostructures are cobalt oxide (Co3O4), zinc oxide (ZnO), and bismuth-zincvanadate (BiZn2VO6) have all been studied in this thesis. Metal oxide nanostructures based electrodes are fabricated on gold-coated glass substrate by low temperature (< 100 0C) wet chemicalapproach. X-ray diffraction, x-ray photoelectron spectroscopy and scanning electron microscopy were used to characterize the electrodes while ultraviolet-visible absorption and photoluminescence were used to investigate the optical properties of the nanostructures. The resultant modified electrodes were tested for their performance as chemical sensors and for their efficiency in PEC activities. Efficient chemically modified electrodes were demonstrated through doping with organic additives like anionic, nonionic or cationic surfactants. The organic additives are showing a crucial role in the growth process of metal oxide nanocrystals and hence can beused to control the morphology. These organic additives act also as impurities that would significantly change the conductivity of the electrodes. However, no organic compounds dependence was observed to modify the crystallographic structure. The findings in this thesis indicate the importance of the use of controlled nanostructures morphology for developing efficient functional materials.

Glyphosate (N-(phosphonomethyl)glycine, PMG, H3L) is a widely used organophosphorous herbicide. It interacts with metal ions and mineral surfaces, which may affect its mobility, degradation and bioavailability in the environment. However, these interactions are far from fully understood. This thesis is a summary of five papers discussing the complexation of PMG with metal ions in aqueous solution and the adsorption of PMG and/or Cd(II) on different mineral surfaces. The complexation of PMG with the metals Cd(II) or Al(III) in aqueous solution was investigated with macroscopic and molecular scale techniques. Potentiometric titration data were combined with EXAFS, ATR-FTIR and NMR spectroscopic data to generate solution equilibrium models. In the PMG-Cd(II) system, only mononuclear complexes were formed, while both mono and binuclear complexes were observed in the PMG-Al(III) system. EXAFS, ATR-FTIR, and XPS measurements showed that PMG adsorbs to the surfaces of goethite (α-FeOOH), aged γ-alumina (γ-Al2O3) and manganite (γ-MnOOH) through one oxygen of its phosphonate group to singly-coordinated surface sites. Surface complexation models consistent with these spectroscopic results were fit to adsorption data using the 1pK reaction formalism. Electrostatic effects were accounted using either the Extended Constant Capacitance Model (ECCM) or the Basic Stern Model (BSM), and the charge of the surface complexes was distributed over the different planes. The formation of the surface complexes was described according to the following reactions: ≡MeOH(0.5-) + H3L <=> ≡MeHL(1.5-) + H2O + H+ ≡MeOH(0.5-) + H3L <=> ≡MeL(2.5-) + H2O + 2H+ The coadsorption of PMG and Cd(II) on the surfaces of goethite and manganite results in the formation of ternary mineral-PMG-Cd(II) surface complexes, as suggested from EXAFS results. Previous EXAFS measurements have also established the coordination geometries for the binary goethite-Cd(II) and manganite-Cd(II) surface complexes. In addition to the surface reactions in the binary mineral-Cd(II) and mineral-PMG systems, a single ternary complex with the stoichiometry ≡MeLCd(OH)(1.5-) was sufficient to explain coadsorption data: ≡MeOH(0.5-) + H3L + Cd2+ <=> ≡MeLCd(OH)(1.5-) + 3H+ It was concluded that the affinity of PMG for the three mineral systems decreases within the series: goethite > aged γ-Al2O3 > manganite. The formation of the ternary surface complex is more significant on goethite surfaces than on manganite surfaces.

La0.6Ca0.4Mn0.8Ni0.2O3-, La0.6Ca0.4Mn0.8Fe0.2O3- und La0.75Ca0.25Mn0.5Fe0.5O3-Volumenmaterialien wurden im potentiometrischen Messaufbau bereits erfolgreich auf ihre NO-Sensitivität getestet. Keramischen Nanomaterialien werden generell eine Reihe neuer oder verbesserter Eigenschaften (verbessertes Sinterverhalten, erhöhte NOx-Sensitivität, höhere Leitfähigkeit) zugesprochen. La0.6Ca0.4Mn0.8Ni0.2O3, La0.6Ca0.4Mn0.8Fe0.2O3 und La0.75Ca0.25Mn0.5Fe0.5O3 wurden mittels PVA/Sucrose-Methode, Aktivkohlemethode und Fällungssynthese als Nanomaterialien sowie mit Festkörperreaktion als Volumenmaterialien dargestellt und mit typischen Charakterisierungsmethoden untersucht. Die Materialien wurden in verschiedenen Schichtdicken auf YSZ-Substrate aufgetragen und potentiometrisch sowie impedanzspektroskopisch auf ihre NO-Sensitivität und die Querempfindlichkeit gegenüber NO2 und Propylen geprüft. Potentiometrische Messungen im NO-Gasstrom ergeben eine Abhängigkeit der NO-Sensitivität von der Partikelgröße, der Schichtdicke und der Beschichtungsmethode. Impedanzspektroskopische Messungen an beidseitig beschichteten YSZ-Substraten zeigen ebenfalls eine Abhängigkeit des Zellwiderstands von der NO-Konzentration und der Partikelgröße. Die Nanomaterialien zeigen bei unterschiedlichen Sauerstoffpartialdrücken im untersuchten Temperaturbereich (300°C bis 850°C) höhere Leitfähigkeiten als die Volumenmaterialien gleicher Zusammensetzung. Dieses Verhalten wird mit dem höheren Sauerstoffaustausch der Nanomaterialien in Verbindung gebracht, der zur Erzeugung zusätzlicher Defekte in der Kristallstruktur führt. Die Nanostruktur und somit eine entsprechend hohe Leitfähigkeit bleiben bei hohen Sintertemperaturen (T > 1000°C), die der Herstellung gasdichter Presslinge dienen, erhalten. XANES- und Photoelektronenspektroskopie wurden verwendet, um die Punktdefekte zu definieren.

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico / A Ãrea deste estudo de hidrogeologia abrange a Bacia do BanabuiÃ, trecho entre Quixeramobim e BanabuiÃ, e està localizada Ãs margens dos rios Quixeramobim e BanabuiÃ. à necessÃrio para os usuÃrios e gestores conhecer os aspectos qualitativos e quantitativos das Ãguas usadas e a interaÃÃo entre as Ãguas dos rios Quixeramobim e Banabuià com os aquÃferos aluvionares. O objetivo deste estudo foi aprofundar os conhecimentos sobre a hidrogeologia dos aluviÃes em relaÃÃo Ãs reservas, qualidade e hidrodinÃmica das Ãguas. Para isto, realizou-se o cadastro de poÃos, monitoramento das variaÃÃes dos nÃveis estÃticos, levantamento planialtimÃtrico, levantamento geofÃsico por resistividade, medidas de parÃmetros fÃsico-quÃmicos, biolÃgicos, metais pesados, anÃlises isotÃpicas (18O e D) nas Ãguas da chuva, dos poÃos, dos rios Banabuià e Quixeramobim, e do aÃude BanabuiÃ. A estimativa das reservas dos aquÃferos aluvionares tambÃm foi realizada. No tratamento e interpretaÃÃo dos dados usou-se o diagrama de Piper, diagrama USSL, Ato e Resist, para interpretaÃÃo das SEVs, programa Surfer 8.0 para simulaÃÃo do fluxo subterrÃneo, e padrÃes de potabilidade da portaria N 2914/2011 do MinistÃrio da SaÃde. Verificou-se que o fluxo subterrÃneo dirige-se na mesma direÃÃo dos rios Quixeramobim e BanabuiÃ, ou seja, em direÃÃo ao Leste. O aquÃfero aluvionar apresenta uma espessura mÃdia da ordem de 7,08 m. A recarga dos aluviÃes no trecho entre Quixeramobim e Banabuià foi de 6,09x106 m3/ano e a reserva permanente à de aproximadamente 34,8x106 m3. Os principais problemas para o consumo humano das Ãguas (superficiais e subterrÃneas) sÃo os coliformes totais, o elemento ferro, a elevada salinidade, o nitrato, o manganÃs e o alumÃnio, estes se encontram com valores acima do permitido pela Portaria n 2914 do MinistÃrio da SaÃde. Portanto, estas Ãguas sà podem ser consumidas apÃs o devido tratamento. Para o uso na irrigaÃÃo, as Ãguas superficiais e dos aluviÃes podem ser utilizadas sem muitos problemas, jà a Ãgua do domÃnio hidrogeolÃgico cristalino, requer uma prÃtica de irrigaÃÃo controlada. A reta meteÃrica local dos isÃtopos estÃveis para o perÃodo estudado foi muito semelhante à GMWL. Os aquÃferos aluvionares recebem alimentaÃÃo pelos rios Quixeramobim e BanabuiÃ. As Ãguas dos poÃos do domÃnio hidrogeolÃgico cristalino sofreram recarga apenas por Ãguas meteÃricas. As Ãguas dos poÃos do aquÃfero aluvionar sugerem que sofreram evaporaÃÃo durante a recarga. Finalmente, ocorre uma estratificaÃÃo (tÃrmica e quÃmica) no perÃodo chuvoso e uma desestratificaÃÃo no perÃodo de estiagem. / The area of this hydrogeological study covers the Banabuià Basin, in the stretch between Quixeramobim and BanabuiÃ, and is located on the banks of rivers Quixeramobim and BanabuiÃ. It is necessary for users and water managers to be aware of the qualitative and quantitative aspects of the water and the interaction between the rivers Quixeramobim and Banabuià and the alluvial aquifers. For these reasons, we sought to deepen the knowledge about the hydrogeology of the alluvial deposits with respect to reserves, hydrodynamics and water quality. Methods included a data bank of wells, monitoring of changes in static levels, a planialtimetric survey, a geophysical survey by electric resistivity, measurements of physico-chemical and biological parameters, heavy metals, stable isotope analyses (18O and D) in rain, waters from wells, rivers Banabuià and Quixeramobim, and Banabuià dam. An estimation of reserves of alluvial aquifers was also made. In the treatment and interpretation of the data Piper and USSL diagrams were used as well as, Ato and Resist for interpretation of VES, program Surfer 8.0 for simulation of groundwater flow; potability standards of Portaria NÂ. 2914/2011 of the Ministry of Health were used to judge water quality. Results indicate that the groundwater flow has in the same direction of rivers Quixeramobim and BanabuiÃ, ie eastward. The alluvial aquifer has an average thickness of approximately 7.1 m. The recharge to the alluvium in the stretch between Quixeramobim and Banabuià was of 6.09 x106 m3/year and permanent reserve is of approximately 34.8 x106 m3. The main problems for human consumption of the waters (surface and groundwater) are total coliforms, the element iron, high salinity, nitrate, manganese and aluminum; these present values higher than permitted by Portaria N 2914. Therefore, these waters can only be consumed after proper treatment. In irrigation, surface water and alluvium can be used without many problems; however, waters from the crystalline domain require a practice of controlled irrigation. The stable isotope local meteoric water line for the period studied showed a slope very similar to the GMWL. The alluvial aquifers receive recharge from rivers Quixeramobim and BanabuiÃ. Wells in the crystalline bedrock receive recharge by rainwater. The waters of the alluvial aquifer wells suggest that they suffered evaporation while recharging. Finally, there is a slight stratification in Banabuià dam (thermal and chemical) in the rainy season that disappears in the dry season.

Submitted by Fabio Sobreira Campos da Costa (fabio.sobreira@ufpe.br) on 2017-05-30T13:01:39Z No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) TESE DILMO MARQUES_2016.pdf: 3410115 bytes, checksum: ef2c4a31a389b0d7af33d59ec444fa24 (MD5) / Made available in DSpace on 2017-05-30T13:01:39Z (GMT). No. of bitstreams: 2 license_rdf: 811 bytes, checksum: e39d27027a6cc9cb039ad269a5db8e34 (MD5) TESE DILMO MARQUES_2016.pdf: 3410115 bytes, checksum: ef2c4a31a389b0d7af33d59ec444fa24 (MD5) Previous issue date: 2016-03-21 / CNPQ / Neste trabalho foram desenvolvidos métodos analíticos, baseados no conceito de multicomutação, para análise de espécies químicas em alimentos. Para isto, foram sintetizados dois materiais: um composto de coordenação usado como fase sólida na determinação de açúcares redutores e uma rede de sílica utilizada como resina de pré-concentração de percloratos. O composto de coordenação cobre (II) - 4,4 '- bipiridina foi usado no desenvolvimento do método para a determinação de açúcares redutores em água de coco e sucos empregando sistema em fluxo multicomutado com detecção espectrofotométrica. A metodologia de análise baseou-se na reação de oxi-redução em meio alcalino entre o reagente sólido e os açúcares redutores. A reação entre a fase sólida (de coloração azul) com (glicose + frutose) resulta em produto de cor amarelada, monitorada em 420 nm. A fase sólida foi fixada em 50 mg e temperatura de 90ºC. Com volume de zona de amostragem de 160 L, que corresponde a 20 ciclos, obtendo resposta linear entre 1,0 e 20,0 g L-1 de AR com RSD de 4,47% (n = 7 ), limite de detecção de 0,2250 g L-1, limite de quantificação de 0,7496 g L-1, freqüência analítica de 75 determinções por hora e geração de efluentes de 320 μL por determinação. Os teores de açúcar redutor encontrados em sucos e água de coco variaram de 38,35 a 98,50 g L-1 e 61,80 a 68,70 g L-1 respectivamente. A rede de sílica, 2,5,8,11,14-pentaoxa-1-silaciclotetradecano, foi empregada num sistema multicomutado como coluna de pré-concentração de perclorato. O sistema foi acoplado a um detector potenciométrico para determinar percloratos em vegetais. Usou-se um eletrodo tubular com membrana constituída por 1% (m/m) de BNIP 4,4 Dapm LC1 solubilizado em 68% (m/m) de 2-nitrodifeniléter, como solvente mediador e 31% (m/m) de poli (cloreto de vinila). Obteve-se limite de detecção de 2,8x10-7 mol L-1, resposta linear no intervalo de 1,0x10-9 a 1,0x10-1 mol L-1, coeficiente de correlação linear de 0,9998 e a coluna apresentou uma capacidade de retenção de 2,86x10-3 mol de perclorato. O sistema foi aplicado às amostras de diferentes vegetais e foram encontradas concentrações de percloratos de 1,30 a 5,08 µg L-1 o teste recuperação variou de 96,5 a 110,8 %. / Two new multicommutation-based analytical methods were developed aiming to the quantification of chemical species in food. The first method is intended to the determination of reducing sugars in coconut water and fruit juices, while the second one is a potentiometric determination of perchlorates in horticultural products. The method eveloped for the determination of reducing sugars uses a multicommuted flow system with spectrophotometric detection employing a (copper (II) - 4,4’ – bipyridyl) coordination compound as the solid-phase reagent. The reaction of the solid blue phase with glucose/fructose resulted in a yellowish solution, which was monitored at 420 nm; 50 mg of the solid phase was used and the temperature was set at 90ºC. The volume of the sample zone was, 160 L, corresponding to 20 cycles, with a linear response of 1.0 e 20.0 g L-1 to the RA and RSD of 4.47% (n = 7), detection limit of 0.2250 g L-1, the limit of quantification was 0.7496 g L-1, analytical frequency of 75 determination per hour and effluent generation of 320 L per determination. The potentiometric method used to determine perchlorates used a tubular electrode formed by a polymeric membrane which showed the best features consisted of 1% (w/w) BNIP Dapm LC1 solubilized in 68% (w/w) of 2-nitrodiphenyl ether as a mediator solvent and 31% (w/w) poly(vinyl chloride) as the polymeric matrix. A limit of detection of 2.8x10-7 mol L-1 was obtained with a linear response in the range of 1.0x10-9 at 1.0x10-1 mol L-1, linear correlation coefficient of 0.9998 and the column retention capacity 2.86x10-3 mol perchlorate. Was applied to samples of different vegetables found perchlorates 1.30 to 5.08 µg L-1 and recovery between 96.5 and 110.8%.

Le présent travail porte sur l’étude de deux protéines de la famille des oxydases à hème-fer par des techniques de spectroscopie et d’électrochimie. Le premier chapitre décrit l’étude du cytochrome bo3 oxydase issue d’E. coli. Nous nous sommes intéressés à l’étude des interactions enzyme-quinone par l’utilisation de quinones avec des longueurs chaines isoprenyl différentes. Notre but est de mieux comprendre le rôle de la longueur de la chaine des quinones sur l’activité catalytique de l’enzyme et sur les propriétés redox des cofacteurs à hème. Dans l’étape suivante, on a étudié les résidus impliqués dans le site de liaison des quinones (haute affinité, QH). Plusieurs mutations de ces résidus sont étudiées pour mieux comprendre l’importance de chacun des résidus dans cette liaison. Dans la dernière partie de ce premier chapitre, la spectroscopie SEIRAS «spectroscopie d’absorption infrarouge exaltée de surface» est introduite comme une technique alternative pour l’étude des protéines membranaires. Dans le second chapitre, la protéine membranaire cNOR issue de P. denitrificans est étudiée. Nous nous sommes focalisés sur l’effet de différents environnements (pH, présence de protéo-liposomes) sur la stabilité de la cNOR. Pour ce faire, trois valeurs de pH (6.5, 7.5 et 8.5) sont choisies et quelques échantillons de cNOR sont reconstitués dans des protéo-liposomes. Enfin, le donneur de proton terminal (au centre binucléaire) dans la protéine cNOR était étudié. De plus, nous avons étudié les ligands des ions Ca2+ puisqu’il est proposé que le donneur de proton est situé proche de cette région. / This thesis is focused on the study of two members of the heme-copper oxidase family by using spectroscopic and electrochemical techniques. In the first chapter cytochrome bo3 oxidase from E. coli was studied. We focused on the quinone-enzyme interactions by using quinones with different isoprenyl chains. Our aim was to better understand the role of isoprenyl chain on the catalytic activity of the enzyme and the redox properties of the heme cofactors. In the next step we studied the residues that are suggested to be in the high-affinity (QH) quinone binding site. Several site-directed mutants of these residues were investigated in order to better understand the position of QH binding site and the importance of each residue. In the last part of this chapter surface-enhanced infrared absorption spectroscopy (SEIRAS) was introduced as an alternative technique to study the membrane proteins. In the second chapter cytochrome c dependent nitric oxide reducates (cNOR) from P. denitrificans was studied. We focused on the effect of different environment (pH, proteoliposomes) on the stability of cNOR. For that purpose three pH values (6.5, 7.5 and 8.5) was selected and some of the cNOR samples were reconstituted in liposomes. Finally, the terminal proton donor (to the binuclear center) in cNOR was investigated. We studied the ligands of the Ca2+ site in cNOR since it was suggested that the proton donor may be close to this area.

Afin de contrôler l’émission totale des NOx dans l’échappement automobile, un capteur potentiométrique à base de zircone stabilisée à l’yttrium a été développé par la technique de sérigraphie. Il est montré que l’utilisation d’un filtre catalytique, déposé directement sur l’élément sensible, permet d’éliminer les interférences venant d’autres gaz réducteurs dans l’échappement, en particulier monoxyde de carbone (CO), hydrogène (H2), hydrocarbures (CxHy) et ammoniac (NH3). En plus, il est possible de fixer avec le filtre catalytique le rapport NO/NO2 correspondant à l’équilibre thermodynamique. Par conséquent la réponse du capteur n’est plus dépendante du rapport NO/NO2, mais seulement de la température. De plus, la sensibilité et la sélectivité du capteur à NO2 peut considérablement être améliorée en appliquant un courant de polarisation. / In order to monitor the total NOx emission in car exhausts, a potentiometric gas sensor based on yttria-stabilized zirconia (YSZ) has been developed by screen-printing technology. It is shown that the use of a catalytic filter directly deposited on the sensing element can successfully eliminate the interferences coming from other reducing gas species in the automotive exhaust such as carbon monoxide (CO), hydrogen (H2), hydrocarbons (CxHy) and ammoniac (NH3). Furthermore, another advantage of the catalytic filter is its capacity to fix the NO/NO2 ratio according to the thermodynamic equilibrium. In that way, the sensor response is no longer dependent on the NO/NO2 ratio in the exhaust, but only dependent on the temperature. Finally, the application of a polarisation current can enhance considerably the selectivity and sensitivity of the sensor towards NO2.

The presented dissertation focuses on non-covalent interactions of hyaluronan of different molecular weights (9–1540 kDa) with basic (oligo)-amino acids (especially arginine) and the antimicrobial peptide cecropin B. High-resolution ultrasonic spectroscopy (HR-US), isothermal titration calorimetry (ITC) and potentiometric titration techniques were chosen to investigate the interactions. The thesis focuses on the characterization of interactions, especially with respect to the used molecular weight of interacting polymers and the ionic strength of the environment. Whether interactions occur or not was determined primarily by the length of the arginine oligomer chain. For monomeric amino acids, the interactions were investigated mainly by potentiometric titrations. Interactions were observable from arginine oligomers with eight monomer units. The molecular weight of hyaluronan mainly affected the intensity of the interactions. The transition between the individual conformations of hyaluronan (rod and random coil) was especially significant. Investigation of interactions was performed in water, in solutions with different concentrations of sodium chloride and in PBS. The sufficiently high ionic strength of the solution was able to suppress the interactions in water between the oligomers of arginine and hyaluronan. The basic antimicrobial peptide cecropin B has been shown to interact with hyaluronan in water but not in PBS. Based on these results, it was possible to conclude that the hyaluronan-cecropin B system would be particularly suitable for topical applications.

Indiana University-Purdue University Indianapolis (IUPUI) / This study investigates the hydrological functioning of a riparian zone in central Indiana in a glaciated valley with concave topography (16% slope gradient) and ground water seeps on the valley walls. Unlike sites found in most riparian zone studies with lateral ground water inputs (Clement et al., 2003; Jordan et al., 1993; Blicher-Mathiesen and Hoffman, 1999; Hoffman et al., 2000), the site in this study is connected to thin, permeable upland sediments (≈2 m). The objectives of this research include: 1) understanding the influence of the hydrogeomorphic (HGM) setting on riparian hydrology (including determining the sources of water to the site), 2) determining how the HGM setting influences riparian zone water quality functioning, and 3) comparing the results from this site with conceptual models of riparian zone hydrologic functioning. Water chemistry and hydrometric data were collected over a 16-month period. Three factors influence riparian zone hydrological functioning at the site: 1) the nature of water contributions from upland sources, 2) riparian zone soil texture, and 3) the location of a preWisconsinan till unit. When the uplands are contributing water to the riparian zone a shallow water table is found near the hillslope and ground water flows from the hillslope to the stream. Conversely, when upland contributions cease a large water table drop occurs and ground water flows in a downvalley direction. Fine textured soils near the hillslope result in shallow water tables and small ground water fluxes. Hydrometric data, water chemistry, and statistical analyses suggest water from an intertill layer adjacent to the site is the primary source of water to the site. NO3- concentrations decreased in ground water flow in the riparian zone suggesting the site is removing nutrients. A preWisconsinan glacial till deposit at shallow depths in the riparian zone limits ground water flow to horizontal flow paths. Overall, the hydrologic functioning of the site agrees well with riparian zone conceptual models (Vidon and Hill, 2004a; Vidon and Hill, 2004b; Devito et al., 1996; Hill, 2000; Baker et al., 2001; Burt et al., 2002). The results of this study are important additions towards conceptualizing riparian zone hydrologic functioning.