The present work related to apply hot-melt ink-jet process for imaging at offset lithographic printing form, to utilise a reusable surface for many times and particularly related to validating thermal and ultrasonic erasing processes. This dissertation investigated systematically the role of certain factors towards affecting erasing image area process on print surfaces. Thermal erasing process approved to melt and suck the image area from the surface, the results were adopted by using contact angle measurements and scanning electron microscope. Ultrasonic erasing process permitted to solve the image area by choosing erasing chemistries, influence of selected erasing chemistries on printing surface, and evaluation the process, the results were tested by UV/Vis spectrometer, contact angle, profileometery and visual microscope. / Der Fortschritt im Bereich von Charakterisierung und Verständnis für Hot-melt Ink Jet Prozesse zur Bebilderung von Offsetdruckform-Zylindern ist ein Ergebnis dieser Forschung. Die Systematik dieser Arbeit basiert auf einem theoretischen Teil, um einen geeigneten Löschprozess auszuwählen. Der Löschprozess hängt von den Eigenschaften des Hot-melt Ink Jet Materials und der genutzten Aluminiumdruckoberfläche ab. Diese werden systematisch im Labormaßstab experimentell untersucht. Der thermische Prozess wurde einerseits durch Benetzbarkeitsprüfungen und anderseites durch Rasterelektronmikroskopaufnahmen bewertet.Der Ultraschallprozess ist ein nasser Löschprozess. Die Untersuchungen wurden in vier Stufen systematisch durchgeführt - Auswahl vom geeigneten Lösungsmitteln - Einflüsse von ausgewählten Lösungsmitteln auf nicht beschichtete und beschichtete Aluminium platten - Evaluation eines Ultraschalllöschprozesses - Validation eines Löschprozesses; zur Bewertung des Löschprozesses wurden mehrere Druckplattenproben bebildert und gelöscht Die Ergebnisse wurden durch UV/Vis Spektrometer, Kontaktwinkel, Profiliometrie und Visuelle Mikroskopie getestet.

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal

La molécule de méthane possède la liaison C-H la plus forte parmi les hydrocarbures (BDE = 104 kcal mol-1) : son oxydation en conditions douces représente un challenge d'importance. La Méthane Monoxygénase particulaire (pMMO) est une enzyme à cuivre qui catalyse l'oxydation du méthane (CH4) en méthanol (CH3OH). Le site actif de l'enzyme est composé d'atomes de cuivre séparés par 2.6 Å. Des recherches récentes suggèrent qu'un cluster Cu2 III,II/O2 à valence mixte soit un intermédiaire-clé du cycle catalytique. L'objectif de ce travail vise à la synthèse et caractérisation de nouveaux complexes dinucléaires à valence mixte de type bis(µ-oxo)Cu2 III,II ou (µ-OH, µ-O)Cu2 III,II. Deux familles de motifs coordinants ont été mises en oeuvre, polypyridyle ou polyamide ; les deux sites sont assemblés par des ponts courts et rigides, phenoxo, naphthyridine ou alkoxo. De nouveaux complexes ont été caractérisés par électrochimie, spectroscopies UV-visible et RPE, et par des calculs théoriques. Un dispositif original de cryo-spectroélectrochimie UV-vis-NIR a été développé en parallèle de cette étude : il permet l'identification spectroscopique d'intermédiaires transitoires, réputés très instables à température ambiante. De nouveaux composés à valence mixte, Cu2 III,II(μ-OH, μ-O) et Cu2 III,IIbis(μ-OH) ont été identifiés. Ces résultats élargissent le champ des données de cette famille d'intermédiaires instables limitée jusqu'ici à un seul exemple. / Methane has the strongest C-H bond of any hydrocarbon (BDE = 104 kcal mol-1); its oxidation under mild conditions remains a great challenge. The particulate Methane Monooxygenase (pMMO) is a copper enzyme that oxides methane (CH4) to methanol (CH3OH). In the active site of the enzyme, two copper ions are located at a short distance (2.6 Å). Recent researches have suggested a mixed-valent Cu2III,II/O2 cluster as a key intermediate in the catalytic cycle. The main objective of this work was the synthesis and characterization of new mixed-valent CuIIICuII bis(μ-oxo) and (μ-OH, μ-O) dinuclear complexes. For this purpose we designed promising symmetrical and unsymmetrical complexes based on specific and distinct scaffolds for each side of the structure. Two families of coordination pattern have been used, polypyridyle or polyamide; the two sites are shortly and rigidly bridged by phenoxo, alkoxo or naphthyridine linkers. New complexes have been characterized by electrochemistry, UV-vis and EPR spectroscopies, and by theoretical calculations. A new cryo-UV-Vis-NIR spectroelectrochemical set up, developed in parallel during this work, has allowed the spectroscopic identification of these transient intermediate species, known to be unstable at room temperature. New mixed-valence Cu2 III,II(μ-OH, μ-O) and Cu2 III,IIbis(μ-OH) complexes have been characterized. These results expand the recent knowledge on the only mixed valent CuIII(μ-OH)CuII species described so far.

Submitted by Janine Contro null (janinecontro@yahoo.com.br) on 2016-04-07T18:56:18Z No. of bitstreams: 1 DISSERTAÇÃO - JANINE.pdf: 7764303 bytes, checksum: a8fc2422ef9a7fc1ce8eef29ce54e487 (MD5) / Approved for entry into archive by Felipe Augusto Arakaki (arakaki@reitoria.unesp.br) on 2016-04-08T12:32:48Z (GMT) No. of bitstreams: 1 contro_j_me_sjrp.pdf: 7764303 bytes, checksum: a8fc2422ef9a7fc1ce8eef29ce54e487 (MD5) / Made available in DSpace on 2016-04-08T12:32:48Z (GMT). No. of bitstreams: 1 contro_j_me_sjrp.pdf: 7764303 bytes, checksum: a8fc2422ef9a7fc1ce8eef29ce54e487 (MD5) Previous issue date: 2016-03-11 / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Foram sintetizados neste trabalho novos vanadosilicatos, para suas sínteses foram utilizadas moléculas orgânicas derivadas de 3,5-dimetilpiperidina (SDAs 1 – 4) e 2,6-dimetilpiperidina (SDAs 5 – 8) em sua mistura reacional. Os vanadosilicatos foram nomeados seguindo a numeração dos SDAs utilizados em suas sínteses (VN1 a VN8). As caracterizações físico-químicas dos vanadosilicatos foram realizadas utilizando-se técnicas como difração de raios-X (DRX), microscopia eletrônica de varredura (MEV), espectroscopia no infravermelho (FT-IR), espectroscopia Raman, espectroscopia no UV – Visível e ressonância magnética nuclear com rotação em torno do ângulo mágico (RMN-MAS) no estado sólido para os núcleos de 13C, 29Si e 51V. Os resultados experimentais indicam que as moléculas orgânicas podem atuar como agentes direcionadores de estrutura (SDAs). Os SDAs 1, 3, 4 e 5 direcionaram a formação dos vanadosilicatos VN1, VN3, VN4 e VN5 isomorfos ao titaniosilicato ETS-10 e ao vanadosilicato do tipo AM-6, enquanto os SDAs 2, 6, 7 e 8 direcionam a estrutura de novos vanadosilicatos (VN2, VN6, VN7 e VN8). Evidências experimentais da incorporação de vanádio na estrutura cristalina dos materiais foram obtidas por FT-IR, UV – Visível, 29Si RMN-MAS. Na espectroscopia no infravermelho (FT-IR) o sinal localizado na frequência 870 cm-1 é proveniente da vibração da ligação V-O e o sinal centrado na frequência 1030 cm-1 é proveniente da vibração dos grupos vanadila. Na espectroscopia no UV – Visível o comprimento de onda 600 nm representa os grupos vanadila e os comprimentos onda 450 e 545 nm indicam a presença de vanádios em coordenação octaédrica distorcida (VN2) e ordenada (VN1, VN3 e VN4), respectivamente. E no caso do RMN de 29Si o sinal centralizado em -93 ppm é proveniente de núcleos de silício da forma Si(3Si, 1V), estes dados comprovam a incorporação do vanádio na rede cristalográfica do material microporoso. A espectroscopia no UV – Visível juntamente com a ressonância magnética nuclear de 29Si sugerem que os vanadosilicatos isomorfos ao titaniosilicato VN1, VN3, VN4 e VN5 apresentam uma rede cristalográfica mais ordenada que os vanadosilicatos VN2, VN6, VN7 e VN8. Visto que a espectroscopia no UV – Visível indica que os octaedros VO6 dos vanadosilicatos isomorfos ao ETS-10 são mais regulares que os octaedros de vanádio dos novos vanadosilicatos, e os resultados experimentais de RMN-MAS de 29Si revelam que os vanadosilicatos isomorfos ao ETS-10 apresentam somente o sinal centralizado em -93 ppm, proveniente de núcleos de silício da forma Si(3Si, 1V), enquanto os novos vanadosilicatos apresentam, além do sinal centralizado em -93 ppm, um novo sinal centralizado em -110 ppm, proveniente de núcleos de silício da forma Si(4Si, 0V). / New vanadosilicates were synthesized in this work. They have been synthesized using organic molecules derivatives of 3,5-dimethylpiperidine (SDAs 1 – 4) and 2,6-dimethylpiperidine (SDAs 5 – 8) in their reactional mixture. The vanadosilicates were named using the same numbers of the SDA used in their synthesis (VN1 to VN8). Physicochemical characterization of the new vanadosilicates was carried out by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), Raman spectroscopy, UV – Visible spectroscopy (UV – Vis), solid state 13C, 29Si and 51V magic angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy. The experimental results suggest that the organic molecules can act as structure directing agents (SDAs). The SDAs 1, 3, 4 and 5 directed the synthesis to the formation of vanadosilicates VN1, VN3, VN4 and VN5 isomorphs to titanosilicate ETS-10 and vanadosilicate AM-6; on the other hand the SDAs 2, 6, 7 and 8 show selectivity to the formation of new vanadosilicates (VN2, VN6, VN7 and VN8). Experimental evidences of the vanadium incorporation into the vanadosilicate framework were obtained by FT-IR, UV – Vis and 29Si MAS NMR. The infrared spectroscopy has a signal at the frequency of 870 cm-1 designed to the vibration of V-O bond and the signal at the frequency of 1030 cm-1 designed to the vibration of vanadyl groups. The UV – Vis spectroscopy reveals the presence of vanadyl groups at 600 nm and the wavelengths 450 and 545 nm indicate the presence of distorted (VN2) and ordely (VN1, VN3 and VN4) octahedrally coordinated vanadium, respectively. And the 29Si MAS NMR shows a chemical shift centred at -93 ppm assigned to the Si(3Si, 1V) neighbourhood. UV – Vis spectroscopy and 29Si MAS NMR evidence that the vanadosilicates VN1, VN3, VN4 and VN5, isomorphs to ETS-10, show their framework more crystalline than the new vanadosilicates framework (VN2, VN6, VN7 and VN8). This affirmative is supported by both UV – Vis and 29Si MAS NMR data. UV – Vis data indicates that VO6 octahedra in vanadosilicates isomorphs to ETS- 10 are more regular than the VO6 octahedra in the new vanadosilicates. 29Si MAS NMR experimental data shows that vanadosilicates isomorphs to ETS-10 have only one chemical shift centred at -93 ppm, assigned to the Si(3Si, 1V) neighbourhood, while the new vanadosilicates have two chemical shifts that one centred at -93 ppm and other centred at -110 ppm assigned to Si(4Si, 0V) neighbourhood.

Le domaine de la bioénérgétique traîte de la circulation et de la transformation de l’énergie dans et entre des organismes et leur environnement. Dans ce manuscrit de thèse, la respiration cellulaire et plus particulièrement la première enzyme de la chaîne respiratoire, la NADH:ubiquinone oxidoreductase (Complexe I) ont été étudiées, dans l’objectif de clarifier sa fonction et son implication dans certaines maladies. Dans une première partie, la création d’une sonde impliquant l’enzyme immobilisée de façon biomimétique est décrite. La caractérisation de ce système est effectuée via spectroscopie infrarouge par exaltation de surface (SEIRAS) couplée à de l’électrochimie. Sa réponse à l’ajout de substrats et d’inhibiteurs est ensuite présentée. Dans une seconde partie, l’interaction du Complexe I avec des lipides et des inhibiteurs (Zn2+ et NADH-OH) ainsi que le rôle d’une Tyrosine située au site de fixation du NADH ont été étudiés par spectroscopies IR et UV-Vis différentielles induites par électrochimie. L’exploration des résultats obtenus sous un angle structural a finalement permis de proposer un modèle pour le mécanisme de couplage entre la réduction d’ubiquinone et le pompage de protons par le Complexe I. / The field of bioenergetics deals with the flow and transformation of energy within and between living organisms and their environment. The work presented in this thesis report focuses on cellular respiration and more specifically on the first enzyme of the respiratory chain, NADH:ubiquinone oxidoreductase (Complex I). This was done to clarify details about its function and its implication in disease. First, the creation of a sensor involving the biomimetically immobilized enzyme is presented and probed through a combination of surface enhanced infrared absorption spectroscopy (SEIRAS) and electrochemistry. This sensor is then tested against different substrates and inhibitors. In a second part, the interaction of Complex I with lipids, inhibitors (Zn2+ and NADH-OH) and the role of a Tyrosine residue situated in the NADH binding pocket are investigated through electrochemically induced UV-Vis and FTIR difference spectroscopies. The results gathered through these experiments are then explored under a structural perspective and a coupling mechanism between quinone reduction and proton translocation by Complex I is proposed.

Fundação de Apoio a Pesquisa e à Inovação Tecnológica do Estado de Sergipe - FAPITEC/SE / In this work, we analyze the structural, optical and electrical properties of thin films of ZnO - doped with aluminum (Al) and chromium (Cr), with concentrations of 3%, grown by non - reactive magnetron sputtering. The samples were grown using glass as substrates. For the production of the capacitors used in the electric characterization an Al layer was grown on the substrate which was used as the lower electrode. The films studied here were obtained by varying the thickness and temperature of the substrate, between ambient temperature and 400 ° C. The films obtained were characterized by X-ray diffraction (XRD), X-ray reflectometry (XRR), optical spectroscopy in the UV-Vis region, and IxV voltage current plotes. The results showed that the films produced have a large preferential orientation with planes (002) of the ZnO wurtzite hexagonal phase perpendicular to the surface of the substrate. By means of the XRR measurements, the experimental thicknesses were obtained as well as the roughness and mass density of the films. From the UV-Vis measurements, it was observed that the films have a high transmittance (above 80%) with a slight reduction with increasing thickness. The measurements of the IxV curves showed that the films have an ohmic behavior with a low resistance and resistivity, therefore possessing compatible properties to be used with conductive oxides and transparent for both dopants. The bandgap values for all films are close to 3.3 eV without significant variation with the parameters used. / Neste trabalho, são apresentadas discussões sobre as propriedades estruturais, óticas e elétricas de filmes finos de ZnO — dopado com alumínio (Al) e cromo (Cr), com concentrações de 3%, crescidos por pulverização catódica não reativa. As amostras foram crescidas utilizando vidro como substratos. Para a produção dos capacitores utilizados na caracterização elétrica foi crescido uma camada de Al sobre o substrato que foi utilizado como eletrodo inferior. Os filmes aqui estudados foram obtidos variando a espessura e a temperatura do substrato, entre temperatura ambiente e 400 °C. Os filmes obtidos foram caracterizados pelas técnicas de difração de raios X (DRX), reflectometria de raios X (XRR), espectroscopia óptica na região do UV-Vis e curvas de corrente por tensão IxV. Os resultados mostraram que os filmes produzidos possuem uma grande orientação preferencial com planos (002) da fase hexagonal wurtzita do ZnO perpendicular à superfície do substrato. Por meio das medidas de XRR, foram obtidas as espessuras experimentais assim como a rugosidade e densidade de massa dos filmes. A partir das medidas de UV-Vis, foi observado que os filmes possuem uma alta transmitância (acima de 80%) com uma leve redução com o aumento da espessura. As medidas das curvas IxV mostraram que os filmes apresentam um comportamento ôhmico com uma baixa resistência e resistividade, possuindo, portanto, propriedades compatíveis para serem utilizados como óxido condutore e transparente para ambos os dopantes. Os valores do bandgap para todos os filmes são próximos de 3,3 eV sem variação significativa com os parâmetros utilizados. / São Cristóvão, SE

Fundação de Apoio a Pesquisa e à Inovação Tecnológica do Estado de Sergipe - FAPITEC/SE / Rice is one of the most important crops in the world. The waters near the areas of this crop has a raised risk of contamination, once the cultivation of rice requires large quantities of pesticides. Due to their high toxicity, uncontrolled use and high solubility in water, pesticides are considered one of the main pollutants of aquatic ecosystems. This present work aims to develop an efficient method based on solid phase extraction (SPE) techniques and high performance liquid chromatography with spectrophotometric detector in the ultraviolet and visible region with diode array (HPLC UV-Vis/DAD) for determination pesticides deltamethrin, epoxiconazole, pyraclostrobin, pyriproxyfen, tebuconazole and thiamethoxan in irrigated rice water, using biochar of aguapé as an alternative adsorbent for SPE. For that, tests were carried out to optimize the chromatographic conditions and the extraction method. In the extraction stage of the pesticides, the method was optimized using the adsorbents C-18 and bio-carbon produced from aguapé. When the C-18 adsorbent was used, the best results were obtained using 10 mL of acidified acetone at pH 5,0 with formic acid solution, 69 ± 0,5 - 100 ± 5,9%. However, when the biochar was tested as an adsorbent for SPE extraction, it presented satisfactory recovery results between 70 ± 0,7% and 122 ± 10,7% for the concentration levels 0,3 to 1,0 μg mL -1. The methods developed were suitable for the determination of pesticide residues in water samples. Thus, the method of extraction using the bio-pot of water was chosen to be validated, because besides being efficient in the extraction of pesticides, it is also a sustainable option. The parameters evaluated for the validation of the method were: linearity and sensitivity, showing good linear response with determination coefficients above 0,9832 in the range of 0,025 to 10 μg mL-1; selectivity, through matrix effect studies; and limits of detection and quantification in the range of 0,01-0,08 μg mL -1, 0,04-0,3 μg mL -1, respectively. / O arroz é uma das culturas mais importantes no mundo, e as águas próximas das áreas desta cultura possuem elevado risco de contaminação, já que o cultivo de arroz requer a utilização de grandes quantidades de agrotóxicos. Devido à sua alta toxicidade, seu uso descontrolado e sua alta solubilidade em água, os agrotóxicos são considerados um dos principais poluentes dos ecossistemas aquáticos. O presente trabalho tem como objetivo desenvolver um método eficiente baseado nas técnicas de extração em fase sólida (SPE) e cromatografia líquida de alta eficiência com detector espectrofotométrico na região do ultravioleta e visível com arranjo de diodos (HPLC UV-Vis/DAD) para a determinação dos agrotóxicos deltametrina, epoxiconazol, piraclostrobina, piriproxifeno, tebuconazol e tiametoxan em água de cultivo de arroz irrigado. Para tanto, foram realizados testes para otimização das condições cromatográficas e do método de extração. Na etapa de extração dos agrotóxicos, o método foi otimizado utilizando adsorventes comerciais e alternativos. Quando se fez uso do adsorvente C-18, os melhores resultados foram obtidos utilizando 10 mL de acetona acidificado a pH 5,0 com solução de ácido fórmico, 69 ± 0,5 – 100 ± 5,9 %. Já quando o biocarvão produzido a partir de aguapé foi testado como adsorvente para a extração por SPE, apresentou resultados satisfatórios de recuperação entre 70 ± 0,7% – 122 ± 10,7% para os níveis de concentração 0,3 a 1,0 μg mL-1. Os métodos desenvolvidos se mostraram adequados para determinação de resíduos de agrotóxicos em amostras de água. Assim, o método de extração utilizando o biocarvão de aguapé foi escolhido para ser validado, pois além de ser eficiente na extração dos agrotóxicos trata-se também de uma opção sustentável. Os parâmetros avaliados para a validação do método foram: linearidade e sensibilidade, mostrando-se boa resposta linear com coeficientes de determinação superiores a 0,9832 no intervalo de 0,025 a 10 μg mL-1; seletividade, através de estudos de efeito matriz; e limites de detecção e quantificação no intervalo de 0,01 - 0,08 μg mL-1, 0,04 - 0,3 μg mL-1, respectivamente. / São Cristóvão, SE

Sistemas de análises químicas em fluxo com multi-impulsão empregam bombas solenoide como unidade propulsora de fluidos, as quais proporcionam fluxos pulsados. Estes provêm um eficiente transporte radial de massas, o que garante boa homogeneização das soluções envolvidas, mesmo em situações de dispersão limitada. O objetivo principal deste trabalho foi então comparar o desempenho de metodologias envolvendo reagentes imobilizados em sistemas de análises em fluxo com fluxos constantes ou pulsados. Para isto, foram selecionadas as determinações espectrofotométricas de ácido ascórbico em produtos farmacêuticos, utilizando reator tubular de polietileno (50 cm) com MnO2(s) imobilizado, e reação com formaldoxima (0,25 mol L-1); e de carbaril em águas naturais, explorando extração líquido-líquido com xileno imobilizado em membrana de PVDF, e solução de NaOH a 0,1 mol L-1 como fluxo aceptor. Adicionalmente, compararam-se os dois tipos de fluxo em uma nova titulação em fluxo, a titulação monitorada por traçador; a determinação de acidez total em vinagres foi selecionada e utilizaram-se as titulações por injeção em fluxo e programada em triângulo, ambas empregando solução de NaOH a 0,01 mol L-1 como titulante e fenolftaleína como indicador ácido-base, com monitoramento por traçador empregando azul brilhante FCF (ca. 6 mg L-1). Na determinação de ácido ascórbico, o desempenho do sistema com fluxos pulsados foi superior àquele com fluxos constantes quanto ao limite de detecção: 0,33 contra 0,60 mg L-1 (critério 3,3 ?), e à repetibilidade: d.p.r. estimado como 2,5 contra 5,6% (n = 20); quanto à exatidão, não foi encontrada diferença estatisticamente significativa entre o método proposto e o da Farmacopeia Britânica ao nível de confiança de 95%. Na determinação de carbaril, o uso de fluxos pulsados favoreceu a extração do analito, obtendo-se uma sensibilidade 9,3% maior relativamente ao emprego de fluxos constantes, além de uma melhor linearidade da curva analítica; entretanto, o método mostrou-se susceptível a interferência de outros metilcarbamatos, o que comprometeu sua aplicação à análise de águas naturais. Na determinação de acidez total, a exploração de fluxos pulsados proporcionou menores variações da razão dos valores de absorbância relativos ao monitoramento do traçador e do indicador; não foi encontrada diferença estatística entre as titulações em fluxo propostas e o método titulométrico de referência ao nível de confiança de 95% / Multi-pumping flow systems use solenoid pumps as fluid propelling devices, which deliver pulsed flows. These flows provide an efficient radial mass transport, thus good mixing conditions even in limited sample dispersion situations. The main objective of this work was then to compare the performance of methodologies involving immobilized reagents in flow systems with constant or pulsed flows. To this end, the spectrophotometric determinations of ascorbic acid in pharmaceutical products using a 50-cm polyethylene tubular reactor with immobilized MnO2(s) with further colour-forming reaction with 0.25 mol L-1 formaldoxime; and carbaryl in natural waters exploiting liquid-liquid extraction with xylene immobilized in a PVDF membrane and a 0.1 mol L-1 ¬¬NaOH solution as acceptor stream, were selected. Moreover, constant and pulsed flows were compared in relation to a novel strategy for flow titration, named tracer-monitored titration; the determination of total acidity in vinegars was selected and flow injection and triangle-programmed titrations were applied, both using a 0.01 mol L-1 NaOH solution as titrant, phenolphtalein as acid-base indicator and ca. 6 mg L-1 brilliant blue FCF as tracer. Regarding ascorbic acid determination, the pulsed flow system was superior in relation to the constant flow system for detection limit: 0.33 against 0.60 mg L-1 (3.3 ? criterion), and for repeatability: r.s.d. estimated as 2.5 against 5.6% (n = 20); in relation to accuracy, no significant differences between the proposed method and that of the British Pharmacopoeia were found at the 95% confidence level. Regarding carbaryl determination, use of pulsed flows favored the analyte extraction, leading to a 9.3% sensitivity improvement in relation to use of constant flows; besides the attainment of better linearity of the analytical curve. The method was however susceptible to interference of other methylcarbamates, thus the application to natural water analyses was impaired. Regarding total acidity determination, pulsed flows exploitation provided lower variations in the ratio of absorbance values related to the monitoring of tracer and indicator; no significant differences between the proposed titrations and the reference method were found at the 95% confidence level

Kohlenstoffnanoröhren (engl. carbon nanotubes, CNT)-Polymer-Komposite haben ein großes Potential im Bereich sensorischer Anwendungen. Dabei spielen die elektrischen Eigenschaften des Komposits und deren Änderungen unter mechanischer Belastung eine entscheidende Rolle. Einen maßgeblichen Einfluss nimmt dabei das Aspektverhältnis der CNT-Agglomerate sowie der CNTs selbst ein, welches jeweils vom CNT-Desagglomerationsprozess bestimmt wird. Die Dispergierung beeinflusst folglich auch die elektrische Leitfähigkeit und Reproduzierbarkeit des Komposits sowohl im mechanisch unbelasteten als auch belasteten Zustand. Dies wurde anhand von (teil-)analytischen Modellen gezeigt. Die Dispersionsqualität wird dabei von vielen Faktoren beeinflusst, wobei die Prozessparameter beim Ultraschalldispergieren derzeit nach der Trial-and-Error-Methode bestimmt werden. Im Rahmen der Arbeit wurde eine Dispergiergleichung für zylindrische Partikel, die CNTs näherungsweise sind, erstmals für die Dispergierung von CNTs in Lösungsmitteln entwickelt, angewendet sowie verifiziert. Die Gültigkeit der Gleichung für CNTs wurde durch Variation der Ultraschallparameter Zeit sowie Energie und deren Einfluss auf den Dispergiergrad gezeigt. Die mittels UV-VIS-Spektroskopie gemessene Extinktion diente dabei als indirekte Messgröße des Dispergiergrads. Nach Vorversuchen zur geeigneten Materialauswahl wurden alle relevanten Einflussparameter berechnet oder experimentell bestimmt. Die experimentelle Verifikation erfolgte an CNT-N-Methyl-2-pyrrolidon-Dispersionen, die mittels Ultraschallsonotrode kontrolliert dispergiert wurden. Im Ergebnis wurde gezeigt, dass die Bestimmung der optimalen Ultraschallparameter möglich ist und die bis dahin übliche Praxis der experimentellen Bestimmung der Dispergierparameter für CNTs ablösen kann. Mithin wurde die Grundlage für die Herstellung elektrisch reproduzierbarer CNT-Polymer-Komposit-basierter Sensoren gelegt. Darüber hinaus wurde das Anwendungspotential dieses Sensorkonzepts für Einzelsensoren zur punktuellen Druckmessung über eine Druckverteilungsmessung als Sensormatrix bis hin zur Anwendung als Einlegesohle im Schuh zur Überwachung des Drucks gezeigt. / Carbon nanotubes (CNT) polymer composites in the field of sensory applications have considerable potential. However, their electrical properties and their changes under mechanical stress play a decisive role. The deagglomeration process of the CNTs also has a great influence on the aspect ratio of the CNT agglomerates as well as the CNTs themselves and thus the electrical conductivity and reproducibility of the composite in both the mechanically unloaded and loaded state.This is shown by means of (partially) analytical models. The dispersion quality is influenced by many factors. The process parameters during ultrasound dispersion are currently being determined by a trial-and-error method. Within the scope of the work, a dispersing equation for cylindrical particles, which are approximate to CNTs, was first developed, applied and verified for the dispersion of CNTs in solvents. The validity of the equation for CNTs was shown by the variation of the ultrasonic parameters time as well as energy and their influence on the degree of dispersion. The absorbance measured by means of UV-VIS spectroscopy serves as an indirect measure of the degree of dispersion. After pre-testing for suitable material selection, all relevant influencing parameters were calculated or determined experimentally. Experimental verification was carried out on CNT-N-methyl-2-pyrrolidone dispersions, which were dispersed in a controlled manner by means of an ultrasonic sonotrode. As a result, it is illustrated that the determination of the optimal ultrasonic parameters is possible and can replace the conventional practice of the experimental determination of the dispersing parameters for CNTs. Accordingly, the basis for the production of electrically reproducible CNT polymer composite-based sensors has been established. In addition, the application potential of this sensor concept ranging from individual sensors for selective pressure measurement over pressure distribution measurement as a sensor matrix to the application as a shoe insole for pressure monitoring was shown.