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Thèse de doctorat--Signal et images--Paris--ENST, 2007. / Bibliogr. p. 205-209. Résumés en anglais et en français.

The study being undertaken was to ascertain the effect or effects of different firing conditions and colorants on glazes composed of wood ash from two trees indigenous to Texas. The problem was divided into two parts: first, to identify the best mixtures using the selected vegetable ash; second, to alter successful glazes with set percentages of colorants. The main objective of the study was to evaluate findings resulting from the variation of elements, firing conditions, and colorants used and to select successful glazes.

Color is a visual characteristic which imparts the ability to categorize different objects. When light strikes an object, there are three possibilities as to what can happen. The light may be reflected, refracted or scattered. Human perception of color is due to a combination of these. Plastics are polymeric materials. Polymers are generally colorless and need colorants in order to have some color. One or more pigments in certain ratios can be used to give a specific color to plastics. Slight variations in the proportions of either of the used pigments, or their dispersion, may result in a color that is different from the desired one. There can also be many other reasons for color mismatch such as processing or degradation effects. This study utilized the historical data records of SABIC IP to look at effects of changing Grade on color (i.e. when the same color is produced from resin blends which may have different amounts of resins, pigments or additives). These records were also used to study effects of change in screw diameter and configuration on color (i.e. when the same grade of a color is produced on two different production lines, different screw diameters and configurations). The effects of the processing parameters on the colors were also investigated by carrying out experiments using a twin screw extruder at SABIC IP’s plant in Cobourg. Resins, pigments and additives were dry blended and extruded while being subjected to different processing conditions. Three processing parameters, namely temperature, rpm and feed-rate, were chosen for the study. A three level factorial design of experiments was used. An analysis of variance (ANOVA) has been utilized to find the effects of individual parameters on color and the interaction between two parameters and their cumulative effect on color. / UOIT

Reproduction de : Thèse de doctorat : Sciences des agroressource : Toulouse, INPT : 2005. / Titre provenant de l'écran-titre. Bibliogr. 122 réf.

En el presente trabajo se han diseñado, construido y evaluado dos fluorosensores miniaturizados y portátiles, que pueden representar una alternativa a la instrumentación analítica clásica de elevado coste, gran tamaño y elevado consumo de reactivos, que necesita de mantenimiento y de personal especializado para su utilización. El empleo de fluorescencia representa intrínsecamente una ventaja en términos de sensibilidad y minimización de interferencias, ya que existen muy pocas moléculas que sean fluorescentes, y menos aún en la zona vis-NIR del espectro electromagnético. Asimismo, los dos dispositivos desarrollados presentan una gran versatilidad para su posible uso en la detección de diversos analitos en función del optodo seleccionado. Los optodos empleados en los dispositivos desarrollados incluyen cromo(fluoro)ionóforos que han sido diseñados, sintetizados y caracterizados en el presente trabajo para operar con la instrumentación miniaturizada y de bajo coste disponible. Se han diseñado, sintetizado y caracterizado nuevos colorantes cianina (croconinas, cetocianinas y (nor)cianinas-anilinas) para su utilización como cromo(fluoro)ionóforos en optodos, tanto en medidas basadas en absorbancia como en fluorescencia.El primer dispositivo opera integrado como detector en un sistema de análisis por inyección de flujo continuo (FIA), y tanto con un optodo selectivo a potasio, como con uno selectivo a plomo, ha mostrado unas apropiadas características analíticas. Su utilización en la determinación de potasio en muestras dopadas de agua potable de red y de plomo en extractos de suelos contaminados ha demostrado su aplicabilidad en muestras reales. El segundo dispositivo consiste en una sonda más portátil y manejable y en la que la intercambiabilidad de la membrana es más fácil, para realizar medidas in-situ y en discontinuo. Ésta se ha activado químicamente con un optodo selectivo a plomo y ha mostrado adecuadas propiedades analíticas de respuesta. Finalmente, se ha aplicado a la determinación de plomo en muestras naturales, verificándose su buen funcionamiento. / In this study two miniaturized and portable fluorosensors were designed, constructed and evaluated. These sensors represent an alternative to classical analytical instrumentation which can be expensive, bulky and reagent dependent, not to mention the need for specialized technicians for its use and maintenance. The use of fluorescence represents an intrinsic advantage with regard to sensibility and interference minimization, since few fluorescent molecules exist in the vis-NIR region of the electromagnetic spectrum. These devices are also versatile; depending on the selected optode they can be used in the detection of diverse analytes. The optodes employed in these devices include chromo(fluoro)iononophores and were designed, synthesized and characterized in this study to operate with miniaturized and low-cost instrumentation. New cyanine dyes (croconines, ketocyanines and (nor)cyanine-anilines) were designed, synthesized and characterized for use as chromo(fluoro)iononophores in optodes for absorbance-based measurements as well as for fluorescence-based measurements. The first device operates as an integrated detector in a continuous flow injection analysis (FIA) system and showed excellent analytical performance with a potassium-selective optode, as well as with a lead-selective one. Its use in the determination of potassium in doped potable water samples, and of lead in contaminated soil extracts, demonstrates its applicability to natural samples. The second device consists of a more portable and user-friendly dip-probe which facilitates the interchangeability of the membrane when in-situ and continuous measurements are carried out. The dip-probe device was chemically activated with a lead-selective optode and also demonstrated good analytical response properties.Finally, this second device was applied to lead determination in natural samples, resulting in positive verifiable performance.

The study being undertaken was to ascertain the effect or effects of different firing conditions and colorants on glazes composed of wood ash from two trees indigenous to Texas.

L’utilisation de colorants synthétiques se développe depuis de nombreuses années dans des différentes industries. Les procèdes les plus couramment utilises pour le traitement des eaux usées colorées sont les traitements biologiques mais ils ont leurs limites. Les techniques d’oxydation chimique traditionnelle quant a elles conduisent à la coupure de la molécule au niveau du chromophore ne peuvent pas minéraliser totalement des colorants alors que la dépollution complète de ces effluents l’exigerait. Le procède photo-fenton homogène est une technique de traitement qui peut dégrader les effluents colores efficacement. Mais il y a quelques inconvénients majeurs qui limitent l’application industrielle de cette technologie. L’objectif de ce travail de recherche était d’étudier la décoloration et la dégradation des solutions des colorants: acide orange 7 acide orange 8 acide rouge i4 acide rouge 73 et acide bleu 74 par le procède d’oxydation avancée: photo-Fenton heterogene. Dans ce procède la zeolite fe-zsm5 a été utilisée comme un catalyseur heterogene. L’application de ce système nous a permis d une part de diminuer la quantité de boue formée au cours du traitement ainsi que la consommation d’énergie électrique engendrée par l’utilisation d’UV estimée à l aide de la méthode figures-of-merit et d’autre par d’étendre l’application du procède type photo-fenton aux ph plus élevés. La modélisation des procèdes étudies a été faite par deux méthodes à la méthodologie de surface de réponse (RSM) et les réseaux neuronaux artificiels (ANNS) - afin d optimiser la performance de système et également d'évaluer les effets simples et combines des différentes variables sur l’efficacité du traitement. / Large amounts of dyes are annually produced and applied in different industries. The biological methods are widely used for treatment of coloured ef fluents, but they have some limitations. Traditional chemical oxidations that destroy the chromophore of the molecule could not also result the complete mineralisation of the dyes. Homogeneous photo-fenton is a promising technique for treatment of the effluents but there are still some drawbacks that limit the industrial applications of this method. The aim of this work was to study the decolourisation and the degradation of coloured solution containing acid orange 7 acid orange 8 acid red I4 acid red 73 or acid blue 74 by an advanced oxidation process: heterogeneous Photo-fenton. In this study zeolite fe-zsm5 was used as a heterogeneous catalyst. Application of this system not only allowed us to diminish the quantity of sludge formed during the process but also reduced the consummation of electrical energy process keeps its high efficiency even at neutral phs. The modelling of the process was done by two methods - response surface methodology (RSM) and artificial Neural networks (ANNS) in order to optimise the performance of the system and to evaluate the simple and the combined effects of different variables on the process efficiency.

Thèse de doctorat : Procédés biotechnologiques et alimentaires : INPL : 2009. / Titre provenant de l'écran-titre.

L’objectif de cette thèse a consisté à développer des systèmes moléculaires capables de convertir l’énergie solaire en des formes directement utilisables par l’Homme : l’énergie chimique et l’énergie électrique. Les deux premiers chapitres décrivent la conception et la synthèse de systèmes moléculaires artificiels en vue de reproduire la fonction de photoaccumulation de charges de l’appareil photosynthétique naturel. Pour accomplir cela, notre stratégie, inspirée de celle de la Nature, a consisté en la synthèse d’un édifice moléculaire de structure étoilée, composé de plusieurs antennes moléculaires (photosensibilisateurs) liés de façon covalente à un accepteur d’électrons organique capable d’accueillir deux charges négatives sous illumination. A cet accepteur a ensuite été substitué un catalyseur de réduction des protons en hydrogène, dans le but de générer une production d’hydrogène sous un flux lumineux, à l’instar du complexe d’oxydation de l’eau de l’appareil photosynthétique naturel. Les deux derniers chapitres présentent le développement d’une méthode de stabilisation des systèmes moléculaires à la surface des semi-conducteurs, dans la cadre de la conception de cellules photovoltaïques hybrides à colorant. En vue d’améliorer les performances de celles-ci, ces travaux ont consisté en la synthèse de colorants fonctionnalisés faisant l’objet d’un procédé de réticulation après chimisorption sur un semi-conducteur, offrant ainsi de nouvelles perspectives en termes de stabilité et de durée de vie des cellules. / The aim of this thesis concerns the development of new photomolecular systems to convert solar energy into chemical and electrical energy. The first two chapters involve the synthesis of new molecular materials to mimic the charge photoaccumulation function of oxygenic photosynthesis. Our strategy consists in the synthesis of a star-shaped molecular architecture, composed of several molecular antenna (photosensitizers) covalently bound to an organic electron acceptor, which is able to host two negative charges upon illumination. To this acceptor has been substituted a proton reduction catalyst in order to generate a hydrogen production under a light irradiation, as the oxygen-evolving complex in the natural photosynthetic. The last two chapters describe the development of a stabilization approach of molecular systems at a semiconductor surface, in the context of the conception of dye-sensitized solar cells. In order to improve their performances, this work has consisted in the synthesis of functionalized dyes which were subjected to a reticulation process after chemisorption onto a semiconductor, providing new perspectives in terms of interface stability and solar cells lifetime.