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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
111

Mélange d'un scalaire dans un jet turbulent : influence d'un obstacle. / Scalar mixing in turbulent jets : influence of an obstacle

Ducasse, Marie laure 12 December 2012 (has links)
Cette étude s'intéresse aux risques associés à la formation d'une ATmosphère EXplosive (ATEX) née d'une fuite d'hydrogène et de sa dispersion dans l'air ambiant. La fuite a été modélisée par un jet turbulent à densité variable libre, impactant sur une sphère de diamètre 20mm ou sur une plaque plane. Dans un premier temps, les champs de vitesses et de concentration ont été obtenus expérimentalement en proche sortie grâce à des mesures de Vélocimétrie par Images de Particules (PIV) et de Fluorescence Induite par Plan Laser sur l'acétone (PLIF). La turbulence et le mélange ont été caractérisés pour le cas d'un jet libre ou en présence d'un obstacle. A partir de ces mesures, la structure générale de l'écoulement a été étudiée à partir des champs moyens et fluctuants par comparaison avec les données de la bibliographie. Puis, les données issues des fluctuations ont été analysées statistiquement par l'étude des fonctions de densité de probabilité du scalaire. Ces travaux se sont poursuivis avec la mise en relation des résultats expérimentaux avec ceux obtenues par des simulations numériques DNS (Direct Numerical Simulation) utilisant la méthode Boltzmann sur Réseau (LBM) d'un scalaire passif dans un jet d'air. Cette étude a permis de recueillir et d'analyser des données supplémentaires sur le mélange d'un jet à masse volumique variable libre ou impactant. Ces données sont directement applicables à la maitrise des risques liés aux fuites d'hydrogène. / This study examines the risks associated with the formation of an explosive atmosphere from a hydrogen leak and its dispersion into the air. We considered the leak as a turbulent jet with density variable, free and impinging a $20,mm$ diameter sphere or a flat plate. Firstly, velocity and scalar fields have been measured experimentally in the near field through Particle Image Velocimetry (PIV) and acetone Planar Laser Induced Fluorescence (LIF). Turbulence and mixing have been defined in the case of free jet and impinging jet. From this measurements, the flow structure has been presented from the mean and fluctuating flow measurements by comparison with literature data. Next, the fluctuation scalar fields are studied with the probability density function method. Finally, a comparison has been conducted between the experiments and direct numerical simulation (DNS) of turbulence based on the lattice Boltzmann method (LBM) for passive scalar in air jet. This study is gathering and analyzing data on the mixing of jet with density variable, free and impinging jet. Such data is directly useful to identify and control risks incurred due to hydrogen leak.
112

Biogas valorization for chemical industries via catalytic process / Valorisation de biogaz pour industrie chimie par voie catalytique

Taimoor, Aqeel Ahmad 15 November 2010 (has links)
La production de l'hydrogène à partir de biomasse est actuellement à l'étude mais la méthode de valorisation du biogaz (mélange H2/CO2) par réactions catalytiques, autres que la simple combustion, n'a pas encore été retenue. Par conséquent, le principal objectif de ce travail est d'explorer les autres voies. L'effet du CO2 sur le système catalytique est mal connu et seulement un effet négatif sur la dissociation de l'hydrogène a été mentionné. L'hydrogénation du toluène sur un catalyseur Pt a d'abord été étudiée sans CO2 pour suivre son comportement et éventuellement sa perte d'activité. En présence de CO2, l'inactivité complète du catalyseur pour l'hydrogénation du toluène a été mis en évidence. La modification de la surface du catalyseur par le CO2 est quantifiée par DRIFT et un mécanisme à deux sites a été montré. La réaction de Reverse Water Gas Shift produisant du CO se trouve être la principale cause de la désactivation de la surface de catalyseur avec le CO2. Donc la compétition d'adsorption entre le CO et des acides carboxyliques a été mise à profit pour favoriser sélectivement la conversion des acides. Pour l'alumine, elle est polluée par des carbonates complexes venant du CO2. La silice étant aussi connue pour promouvoir la décomposition, ces supports ont été rejetés. L'oxyde de titane a été utilisé pour catalyser une autre gamme de produits. Sur ce catalyseur, le changement de sélectivité entre le RWGS et la conversion de l'acide a été observé. Quant à l'oxyde de fer (catalyseur moins actif), il n’est pas capable de produire du CO à partir du CO2. La chimie de surface de l'oxyde de fer joue un rôle important sur la sélectivité du produit parmi les cétones et les aldéhydes. Un mécanisme à deux sites peut réutiliser pour l'oxyde de fer, montrant qu'un fonctionnement stable peut être trouvé si la réduction par l'hydrogène est continue. Si l'oxyde de fer est totalement oxydé par le CO2, produit de réaction, la production des cétones cesse. Énergiquement, le procédé de production d'acétone peut être autosuffisant et l'acétone peut être utilisée comme une molécule de stockage d'énergie. Le procédé va aussi compenser le nouveau procédé de production de phénol qui ne produit pas l'acétone / Hydrogen potential from biomass is currently being studied but ways of valorization of such biogas (H2/CO2 mix) via catalytic reaction, other than simply burning has not yet been considered. Thus the main objective of this work is the exploration of such methods. Effect of CO2 over catalytic system was not well known and only hydrogen dissociation inhibition is reported. Toluene hydrogenation over Pt catalyst is studied and activity loss transition behavior is observed with no CO2 where as complete catalyst inactivity for toluene hydrogenation is found in presence of CO2. Catalyst surface change by CO2 is quantified by DRIFT analysis and two-site mechanism is found to prevail. Reverse water gas shift reaction producing CO is found to be the main cause behind such catalyst surface response to CO2. Adsorption competition between CO and carboxylic acids is exploited for selectivity shift in favor of acids conversion. Alumina support is fouled by carbonates complexes with CO2 while silica is reported to promote decomposition, thus both were rejected and titanium oxide is used instead with a range of products produced. The required selectivity shift between reverse water gas shift and acid conversion is thus observed. Less active iron oxide catalyst further suppresses CO2 conversion. Iron oxide surface chemistry plays an important role over product selectivity among ketones and aldehydes. Two sites mechanism still prevails over iron and stable continuous operation requires simultaneous iron reduction via hydrogen, if totally oxidized by CO2–a reaction product, will cease to produce ketones. Energetically the process devised for acetone production is self sufficient and acetone not only act as an energy storage molecule but can also compensate new phenol production process producing no acetone
113

Vaporization and Combustion Processes of Alcohols and Acetone-Butanol-Ethanol (ABE) blended in n-Dodecane for High Pressure-High Temperature Conditions : Application to Compression Ignition Engine / Procédés de Vaporisation et Combustion des Alcools et de l'Acétone-Butanol-Ethanol (ABE) Mélangés au n-dodécane dans des Conditions de Haute-Pression et Haute-Température : Application au Moteur à allumage par compression

Nilaphai, Ob 18 October 2018 (has links)
La préoccupation de plus en plus importante ces dernières décennies, liée à l’épuisement des ressources pétrolières et au réchauffement climatique par les gaz à effet de serre a accentué l’intérêt du butanol comme carburant alternatif dans le secteur des transports grâce à ses propriétés adaptées pour le moteur à allumage par compression. Cependant, le faible rendement des procédés de production et de séparation empêche encore sa commercialisation en tant que carburant. C’est pourquoi le mélange de fermentation intermédiaire de la production de butanol, Acétone-Butanol-Ethanol(ABE), est de plus en plus considéré comme un carburant alternatif potentiel en raison de ses propriétés similaires au butanol et de ses avantages quant à son cout énergétique pour sa fabrication.Dans ce cadre, ce travail a pour objectif d’étudier l’impact des propriétés de différents mélanges d’ABE et n-dodécane en comparaison avec des mélanges d’alcools (éthanol et butanol) sur le processus de pulvérisation et de combustion et ce,pour différentes proportions en volume allant de 20% à 50%. Pour cela, une nouvelle chambre de combustion appelée"New One Shot Engine ", a été réalisée et utilisée car les conditions haute pression et haute température de "Spray-A" (60bars, 800-900 K et 22,8 kg/m³) définies par le réseau Engine Combustion network (ECN) peuvent être atteintes. Autant les phases liquides et vapeur que de combustion ont été caractérisées grâce à l’utilisation des plusieurs techniques optiques (extinction, Schlieren, chimiluminescence d’OH*) dans des conditions non réactives (Azote pur) et réactives (avec15% d'oxygène). Ces résultats expérimentaux ont non seulement permis d’étudier l’impact en oxygène moléculaire et de fournir une nouvelle base de données fiables, mais aussi d’affirmer la possibilité d’utiliser jusque 20% d’ABE en volume dans des moteurs à allumage par compression, grâce à ses caractéristiques de pulvérisation et de combustion similaires au carburant Diesel conventionnel. / The growing concern in recent decades, linked to the depletion of oil resources and global warming by greenhouse gases has increased the interest of butanol as an alternative fuel in the transport sector. However, the low yield of production and separation processes still prevents its commercialization as a fuel. Therefore, the intermediate fermentation mixture of butanol production, Acetone-Butanol-Ethanol (ABE), is increasingly considered as a potential alternative fuel because of its similar properties to butanol and its advantages in terms of the energy and cost in the separation process.The context of this work aims to study the impact of fuel properties on the spray and combustion processes of ABE mixture and alcohol fuels, blended with the diesel surrogate fuel, n-dodecane, in different volume ratio from 20% to 50%. A new combustion chamber called "New One Shot Engine," was designed and developed to reach the high-pressure and high temperatureconditions of "Spray-A" (60 bar, 800-900 K and 22.8 kg/m³) defined by the Engine Combustion Network (ECN).The macroscopic spray and combustion parameters were characterized by using the several optical techniques (extinction,Schlieren, chemiluminescence of OH*) under non-reactive (pure Nitrogen) and reactive (15% of oxygen) conditions. These experimental results not only made it possible to study the molecular oxygen impact and provide a new accurate database,but also to affirm the possibility of using ABE up to 20% by volume in compression-ignition engines, as its spray and combustion characteristics similar to conventional diesel fuel.
114

[en] COMPUTER CALCULATION OF METASTABLE GAS EQUILIBRIUM FOR THE ACETONE SYNTHESIS FROM ETHANOL AND EVALUATION OF THE CHEMICAL ACTIVITY OF CARBON ON THE METHANATION OF CO2 / [pt] CÁLCULO COMPUTACIONAL DO EQUILÍBRIO METAESTÁVEL DE GASES PARA A FORMAÇÃO DE ACETONA A PARTIR DE ETANOL E ESTUDO DA ATIVIDADE QUÍMICA DO CARBONO NA METANAÇÃO DE CO2

PABLO ESTEBAN SALINAS SOLIS 07 January 2019 (has links)
[pt] Esta tese tem como objetivo estudar a viabilidade termodinâmica da reação de acetona a partir de etanol e água realizando cálculos utilizando o programa Thermo-Calc e a base de dados SSUB3 para equilíbrios de gases metaestáveis. Para a validação do método utilizado inicialmente foi calculado o equilíbrio para a reação da metanação de CO2 com H2, esse cálculo ocorreu sem grandes problemas e ainda foi adicionado o estudo da atividade química do carbono para evitar deposição de carbono sólido nos catalisadores. Para os cálculos da acetona foi considerado um equilíbrio metaestável pois ele não foi calculado utilizando todas as espécies químicas possíveis, isso foi feito para simular o efeito de catalisadores, que inibem a formação de algumas dessas espécies, já que se o cálculo fosse feito sem levar isso em conta se notou que a reação que ocorre é a de reforma do etanol pela água. A conversão de etanol e a seletividade das espécies químicas presentes em maior quantidade foram determinadas em função da temperatura e da razão de etanol e água, e os resultados obtidos foram comparados com dados experimentais obtidos com catalisadores diversos. / [en] The mean goal of this thesis is to study the thermodynamic viability of the acetone formation reaction from ethanol and water by performing calculations using the program Thermo-Calc and the SSUB3 database for metastable gas equilibrium. As a validation of the method used the equilibrium was calculated for the methanation reaction of CO2 with H2. This calculation occurred without problems so the study of the chemical activity of the carbon was also added to avoid the deposition of solid carbon on the catalysts. For the acetone calculation, it was considered a metastable equilibrium because it was not possible to calculate using all possible chemical species. This was done to simulate the effects of catalysts, which inhibit the formation of some of these species. If the calculation was made with all chemical species, it was noted that the net reaction is the reform of ethanol by water.The conversion of ethanol and the selectivity of the chemical species present in greater quantities were determined as a function of temperature and ethanol and water ratio, and the results obtained were compared with experimental data obtained with different catalysts.
115

[en] PROMOTION OF MONOCLINIC ZIRCONIA REDOX PROPERTIES BY DOPING WITH ZINC FOR THE ACETONE SYNTHESIS FROM ETHANOL / [pt] PROMOÇÃO DAS PROPRIEDADES ÓXIDO-REDUTORAS DA ZIRCÔNIA MONOCLÍNICA DOPADA COM ZINCO NA SÍNTESE DE ACETONA A PARTIR DO ETANOL

16 July 2020 (has links)
[pt] Esta tese descreve a síntese de um óxido misto de Zn e Zr (ZnxZr1-xOy), mediante uma técnica ainda não reportada e a utilização deste material na síntese de acetona a partir de etanol. O objetivo foi desenhar um catalisador com propriedades óxido-redutoras e capacidade de se autorregenerar após cada ciclo. A zircônia monoclínica (m-ZrO2) é um óxido já usado em catálise devido às suas propriedades ácido-básicas, mas com fracas propriedades óxido-redutoras. Estas últimas poderiam ser promovidas mediante dopagem substitucional deste material. A inserção de pequeníssimas quantidades de Zn na rede da m-ZrO2, mostraram um incremento apreciável na sua redutibilidade. O material obtido foi caracterizado por diversas técnicas e testado na obtenção de acetona a partir de etanol. O resultado indicou que a dopagem permitiu a formação de vacâncias de oxigênio, as quais promoveram a mobilidade do oxigênio até a superfície e, com isso, aumentaram redutibilidade do material. A seletividade da reação de conversão de etanol teve como produto maioritário a acetona. Foi demostrado que a regeneração do catalisador se deve a espécies oxidantes provenientes da dissociação da água presente no médio reacional; esta dissociação ocorreu nas vacâncias superficiais. Assim, demonstrou-se que a técnica desenvolvida no presente estudo, além de simples, resultou efetiva na síntese do óxido misto de Zn e Zr, um catalisador de composição simples, capaz de conduzir os diferentes passos do mecanismo na síntese de acetona. Considera-se que esta é a primeira etapa na sua viabilização comercial. / [en] This thesis describes the synthesis process of a mixed oxide with Zn and Zr (ZnxZr1-xOy), through a not yet published technique, as well as the utilization of this material in the acetone synthesis from ethanol. The mean goal was to design a catalyst with enhanced oxy-reduction properties and capability for selfregeneration after each cycle. Monoclinic zirconia (m-ZrO2) is already used in catalysis due to its acidic-basic properties, although its oxy-reduction properties are negligible. The enhancement of the oxy-reduction properties can be reached by substitutional doping of this material with a lower oxidation state metal. The insertion of very small quantities of Zn in the m-ZrO2 lattice, showed a high increment of its reducibility. The mixed oxides obtained were characterized by several techniques and catalytically tested in the acetone synthesis from ethanol. The results showed that doping allows the formation of oxygen vacancies, which allow oxygen mobility and therefore, the enhancement of reducibility. The reaction selectivity had acetone as majority product. It was shown that water is also produced and that it is dissociated in the oxygen vacancies generating oxidant species. The catalysts regeneration occurs due to those oxidant species. Therefore, it was demonstrated that the technique developed in this study was easy and effective in the synthesis of the mixed oxide with Zn and Zr, a catalyst with simple composition able to conduct every step of the acetone synthesis. This is considered the first step in the commercial feasibility of this material.
116

Состояние поверхности и магнитные свойства аморфного сплава на основе кобальта : магистерская диссертация / Surface condition and magnetic properties of an amorphous Co-based alloy

Некрасов, Е. С., Nekrasov, E. S. January 2022 (has links)
В работе представлены результаты исследования влияния состояния поверхности ленты на распределение намагниченности и магнитную проницаемость аморфного магнитомягкого сплава Co–Ni–Fe–Cr–Mn–Si–B, а также неоднородности магнитных характеристик в исходном (закаленном) состоянии, Такие исследования имеют важное значение для оптимизации магнитных характеристик и способствуют повышению качества изделий из этого сплава. Состояние поверхности ленты изменяли при помощи термообработок на воздухе в интервале температур 90–380 оС, обработкой водой и ацетоном, формированием полимерного покрытия. Исследования показали, что ленты аморфного сплава Co–Ni–Fe–Cr–Mn–Si–B в закаленном состоянии обладают существенной неоднородностью магнитных характеристик, которая носит закономерный характер и может быть связана с технологией изготовления ленты. Обработка водой приводит к окислению и гидрированию поверхности ленты и ее влияние зависит от знака константы магнитострикции (λs). В состоянии с λs<0 способствует увеличению объема доменов с ортогональной намагниченностью и остроты магнитной текстуры в плоскости ленты, определяемой отношением объемов доменов с планарной намагниченностью, ориентированной вдоль и поперек оси ленты. В состоянии с λs>0 вызывает уменьшение объема доменов с ортогональной намагниченностью и остроты магнитной текстуры. Обработка ацетоном вследствие его окисления и гидрирования содержащимися в поверхности ионами водорода и кислорода оказывает влияние на распределение намагниченности в ленте противоположное воздействию воды, которое также зависит от знака константы магнитострикции. Увеличение длительности обработки ацетоном приводит к усилению ее влияния на изменение объема доменов с ортогональной намагниченностью и ослаблению влияния на перераспределение намагниченности в плоскости ленты. Низкотемпературный отжиг в интервале температур 90 –130оС не способствует изменению максимальной магнитной проницаемости, объема доменов с ортогональной намагниченностью и знака λs, но способствует перераспределению намагниченности в плоскости ленты в результате в результате взаимодействия с атмосферным паром. Наблюдаемое сильное уменьшение максимальной магнитной проницаемости при температурах выше 180 оС связано с ростом объема доменов с ортогональной намагниченностью и снижением остроты магнитной текстуры в плоскости ленты. При 250оС обнаружено формирование поперечной магнитной анизотропии. Полимерное покрытие, формируемое на ленте в закаленном состоянии при 90 –130оС, способствует повышению максимальной магнитной проницаемости и уменьшению объема доменов с ортогональной намагниченностью во всем интервале температур. Полученные результаты находят объяснение в рамках влияния анизотропных напряжений, индуцируемых в ленте в результате взаимодействия ее поверхности с химически активными средами, магнитоактивным полимерным покрытием и анизотропной поверхностной кристаллизацией. / The paper presents the results of the influence of the ribbon surface state on the magnetization distribution and magnetic permeability of amorphous magnetically soft Co-Ni-Fe-Cr-Mn-Si-B alloy, as well as heterogeneity of magnetic characteristics in the initial (as-quenched) state. The state of the ribbon surface was changed by heat treatment in the air in the temperature range 90-380oC, treatment with water and acetone, formation of a polymer coating. The studies showed that the Co-Ni-Fe-Cr-Mn-Si-B amorphous alloy ribbons in the as-quenched state have a significant heterogeneity of magnetic characteristics, which has a natural character and can be associated with the tape manufacturing technology. The water treatment leads to oxidation and hydrogenation of the strip surface and its influence depends on the sign of the magnetostriction constant (λs). In the state with λs<0 the volume of domains with orthogonal magnetization and the sharpness of the magnetic texture in the tape plane, determined by the ratio of the volumes of domains with planar magnetization oriented along and across the tape axis, are increased. In the condition with λs>0 the volume of domains with orthogonal magnetization and the sharpness of the magnetic texture decrease. Treatment with acetone due to its oxidation and hydrogenation by hydrogen and oxygen ions contained in the surface affects the magnetization distribution in the tape opposite to that of water, which also depends on the sign of the magnetostriction constant. Increasing the duration of treatment with acetone leads to increasing its effect on the change in the volume of domains with orthogonal magnetization and to a weaker effect on the redistribution of magnetization in the tape plane. Low-temperature annealing in the temperature range 90 - 130oC does not contribute to changes in the maximum magnetic permeability, the volume of domains with orthogonal magnetization and the sign of λs but contributes to the redistribution of magnetization in the tape plane because of interaction with atmospheric vapor. The observed strong decrease in the maximum magnetic permeability at temperatures above 180oC is associated with an increase in the volume of domains with orthogonal magnetization and a decrease in the sharpness of the magnetic texture in the tape plane. The formation of transverse magnetic anisotropy was detected at 250oC. The polymer coating formed on the tape in the quenched state at 90 - 130oC increases the maximum magnetic permeability and reduces the volume of domains with orthogonal magnetization throughout the temperature range. The obtained results find an explanation in the influence of anisotropic stresses induced in the tape because of interaction of its surface with chemically active media, magnetically active polymer coating and anisotropic surface crystallization.
117

Fumaric Acid Fermentation by Rhizopus oryzae with Integrated Separation Technologies

Zhang, Kun 20 December 2012 (has links)
No description available.
118

Herstellung und Charakterisierung von Antikörpern gegen Triacetontriperoxid (TATP)

Walter, M. Astrid 07 February 2014 (has links)
Die vorliegende Arbeit beschreibt die Herstellung und Charakterisierung der ersten Antikörper gegen Triacetontriperoxid (TATP), einem hoch empfindlichen und unkonventionellen (nicht-kommerziellen) Initialsprengstoff. Entscheidend dafür war die Synthese eines TATP-imitierenden Haptens, welches die typische nonagonale Struktur des TATP mit seinen drei Peroxid- und sechs Methylgruppen nahezu perfekt nachbildet, aber den Vorzug einer zusätzlichen Carboxygruppe zur kovalenten Kopplung an Proteine aufweist. Dadurch konnte das TATP-Hapten an Rinderserumalbumin (BSA) gebunden werden, um ein immunogenes Konjugat zu erzeugen, welches die erfolgreiche Immunisierung zweier Säugetierarten, Maus und Kaninchen, ermöglichte. Der Verlauf der In vivo-Immunisierungen wurde durch die Analyse der Tierseren in regelmäßigen Abständen mittels enzymgekoppeltem Immunoassay (ELISA) verfolgt. Die polyklonalen Antikörper beider Spezies waren ungewöhnlich selektiv gegenüber TATP. Jedoch unterschied sich die Affinität der Antikörper der zwei Spezies um das 5000-fache, wobei die Kaninchenseren den Mausseren überlegen waren. Entsprechend war auch die mit Kaninchenserum erreichbare TATP-Nachweisgrenze von 0.01 µg/L deutlich besser im Vergleich zu 50 µg/L, die mit Mausserum erzielt wurden. Der Messbereich des TATP-ELISA mit Kaninchenserum deckte zudem mehr als vier Zehnerpotenzen ab, wie mittels Präzisionsprofil bestimmt wurde. Die erhaltenen TATP-Antikörper aus Kaninchen stehen damit Anwendungen in Nachweissystemen für die sehr empfindliche Detektion von TATP zur Verfügung, die u. a. in sicherheitsrelevanten Bereichen zum Einsatz kommen könnten. Als erste Anwendung wurde ein TATP-ELISA realisiert, der im Rahmen dieser Arbeit ausführlich optimiert wurde. Außerdem wurden erste Schritte zur Entwicklung eines TATP-Schnelltests (LFA) unternommen. Weitere Biosensoren auf Grundlage der neu entwickelten TATP-Antikörper sind denkbar. / The present work decribes the production and characterization of the first antibodies against triacetone triperoxide (TATP), a highly sensitive and improvised (non-commercial) primary explosive. Crucial to this work was the synthesis of a TATP-related hapten that mimics almost perfectly the typical nonagonal structure of TATP with its three peroxide and six methyl groups. Advantageously, it has an additional carboxylic acid group, which provides a conjugation site for covalent attachment to proteins. Thus, the TATP hapten could be linked to bovine serum albumin (BSA) to produce an immunogenic conjugate, allowing the successful immunization of two different mammalian species, mouse and rabbit. The in vivo immunization progress was followed by periodically analyzing the animals’ sera using enzyme-linked immunosorbent assay (ELISA). The polyclonal antibodies of both species were remarkably selective to TATP. The affinity of these TATP-antibodies was, however, different between the two species, with the rabbit sera showing an affinity about 5000-fold superior than the murine one. Consequently, the TATP detection limit of 0.01 µg/L was considerably better using the sera from rabbit in contrast to 50 µg/L when mouse serum was used. The working range of the TATP-ELISA with rabbit sera covers more than four decades, calculated from a precision profile. The obtained TATP antibodies from rabbit are now available for applications in highly sensitive detection systems for TATP, which could be employed, among others, in security-relevant areas. The first application was the realization of a TATP-ELISA, which was extensively optimized within the course of this work. Furthermore, the first steps towards the development of a lateral flow assay (LFA) targeting TATP were taken, making conceivable further biosensor platforms based on the newly developed TATP antibodies.
119

Enhanced Butanol Production by Free and Immobilized Clostridium sp. Cells Using Butyric Acid as Co-Substrate

Gholizadeh, Laili January 2010 (has links)
Butanol production by four different Clostridium sp. strains was investigated using glucoseP2-medium supplemented with increasing concentrations of butyric acid, added as cosubstrate.Batch fermentations were carried out in serum bottles (freely-suspended cellcultures) and fibrous-bed bioreactor (FBB) with medium recirculation (immobilized cells).Butyric acid clearly revealed to inhibit cellular growth with all specific growth rates decliningupon the increase of butyrate concentrations. However, the presence of low and moderatelevels in the medium can readily enhance the ABE-fermentation and increase butanolproduction through a shift induction towards the solventogenic phase controlled by themedium pH. In all cases it was found that 4.0 g⋅l-1 is the optimal concentration of butyratethat maximizes the yields for all ABE-solvents and butanol productivities. The non-mutant C.acetobutylicum ATCC 824 was singled out as the most efficient butanol productive strainamong all bacteria tested (10.3 g⋅l-1 butanol versus 0.72 g⋅l-1 with and without 4.0 g⋅l-1butyrate, respectively) showing a productivity augment in the order of 0.078 g⋅l-1⋅h-1 (78.5%)and yields of 0.3 g⋅g-1 from substrate and 7.6 g⋅g-1 from biomass versus 0.072 g⋅g-1 and 0.41g⋅g-1 with and without the optimal butyrate concentration, respectively. This strain alsorevealed the best overall tolerance over increasing butyrate concentrations up to ∼6.0 g⋅l-1 andthe highest glucose uptake (65.5%) among all bacteria. Furthermore, the beneficial effects ofbutyric acid were also observed through the use of a fibrous bed-bioreactor when the mutatedstrains of C. beijerinckii ATCC 55025 and BA 101 were tested. The use of this immobilizedcell system effectively improved butanol production over the free system with butanol titersin the fermentation broth around 11.5 g⋅l-1 and 9.4 g⋅l-1 for the two bacteria, respectively,roughly doubling the values attained with the corresponding suspended cell cultures when themedia were supplemented with 4.0 g⋅l-1 of butyrate. All these results confirm theenhancement of butanol formation using either free or immobilized cell culturessupplemented with butyric acid concentrations up to 4.0 g⋅l-1 in the media.
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Processus photophysiques de molécules organiques fluorescentes et du kérosène applications aux foyers de combustion : applications aux foyers de combustion / Photophysical processes of organic fluorescent molecules and kerosene : applications to combustion engines

Rossow, Björn 27 September 2011 (has links)
La métrologie laser basée sur l’analyse de la fluorescence de traceurs moléculaires est devenue l’un des outils clefs pour l’étude expérimentale de la dynamique des fluides réactifs. Une étude spectroscopique des propriétés photophysiques de fluorescence dans le domaine spectral UV-visible de plusieurs molécules fluorescentes appartenant aux cétones aliphatiques et aux aromatiques mono- et bicycliques a permis d’approfondir la compréhension de l’influence de la température, de la pression et de la concentration d’oxygène sur leur fluorescence. Les résultats expérimentaux obtenus ont ensuite permis le développement d’un modèle de simulation du rendement de fluorescence pour les espèces aromatiques (naphtalène et toluène), qui fournit des résultats très proches de ceux mesurés.De ces résultats, le développement de la technique d’imagerie de fluorescence (PLIF) sur la phase vapeur d’un carburant multi-composant a conduit à étendre cette analyse spectrale de fluorescence au cas du kérosène (Jet A-1). La comparaison entre les propriétés de fluorescence du kérosène et des traceurs aromatiques étudiés a notamment permis d’établir une stratégie de mesure de la concentration de la phase vapeur du kérosène dans des environnements où la teneur en oxygène est variable. Les signaux de fluorescence provenant des espèces mono- et di-aromatiques contenues dans le kérosène soulignent des évolutions différentes avec les conditions de température et teneur en oxygène. L’utilisation de filtres optiques appropriés associés à deux caméras ICCD permet alors une mesure bidimensionnelle de la température et de la concentration de kérosène en phase vapeur. La thèse débouche finalement sur l’application de cette technique PLIF-kérosène en combinaison avec la technique PLIF du radical OH en sortie d’un système d’injection industriel multi-point de nouvelle génération intégré dans une chambre de combustion haute pression. / Planar laser-induced fluorescence (PLIF) diagnostic based on the optical excitation of fluorescence tracers has become a key tool for the experimental study of fluid dynamics in reactive flows. A spectroscopic fluorescence study of several organic molecules from aliphatic ketones and mono- and bi-cyclic aromatics in gas-phase was performed in a high-pressure high temperature optical cell. The experimental measurements allowed the understanding of the influence of temperature, pressure and oxygen concentration on the photophysics of these molecules in the UV/visible domain. These results were then used to successfully develop a model of fluorescence yield of the naphthalene and toluene aromatic molecules permitting the simulation of the fluorescence signals with temperature, pressure and species composition in large domains of temperature and pressure.This study has been extended to the case of a multi-component aeronautical fuel (kerosene – jet A1) containing natural aromatics. The comparison of the spectroscopic data recorded in the optical cell to those of the aromatic tracers initially probed has then permitted the definition of a kerosene-PLIF excitation/detection strategy for kerosene vapour concentration measurements in reactive gaseous flowfield containing variable oxygen concentration. Fluorescence signals from mono- and di-aromatic species in kerosene highlight significant differences in evolution with temperature and oxygen concentration. With appropriate optical filters applied to two ICCD cameras, the two-dimensional instantaneous distribution of temperature and concentration of kerosene vapour is then possible to measure in reactive flows. Finally, the kerosene-PLIF diagnostic has been applied at the exit of an innovative multi-point aeronautical injection system integrated to high-pressure kerosene/air combustor test rig. The kerosene-PLIF, combined with the radical OH-PLIF confirmed their implementation in realistic high-pressure flowfields and delivered experimental fruitful experimental information on the effect of the fuel/air mixing on the flame structure in the combustion chamber.

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