Dissertations / Theses on the topic 'Ethanol formation'

Les mélanges GtL/EMHC/éthanol ont un potentiel important comme carburant alternatif pour moteur Diesel.Néanmoins, l'utilisation de ce type de biocarburant en moteur Diesel nécessite une connaissance précise de la cinétiqued'oxydation de ses différents constituants.Une étude bibliographique approfondie a permis de sélectionner quatre espèces modèles représentatives des mélangesGtL/EMHC/éthanol : le n-décane, l'iso-octane, l'octanoate de méthyle et l'éthanol. L'oxydation de mélanges de cesespèces modèles a ensuite été étudiée en réacteur auto-agité à haute pression (10 atm), pour trois richesses (0,5 ; 1 et 2) etsur un large domaine de température (550-1150 K). L'analyse des échantillons par chromatographie en phase gazeuse apermis de quantifier les principaux produits issus de l'oxydation des mélanges étudiés. Un mécanisme cinétique détaillécapable de reproduire l'oxydation des mélanges n-décane/iso-octane/octanoate de méthyle/éthanol a ensuite été mis aupoint. Les prédictions du modèle reproduisent de manière satisfaisante les résultats expérimentaux sur toute la gamme derichesse et de température testée en réacteur auto-agité. L'analyse du modèle a également permis de déterminer les voiesréactionnelles prépondérantes en fonction de la composition des mélanges.Enfin, la combustion de mélanges GtL/EMAG/éthanol a été étudiée en moteur monocylindre Diesel. Cette phased'essais, incluant une analyse approfondie des émissions non réglementées, a permis d'observer l'influence de laformulation des carburants sur l'initiation de la combustion et sur la composition des gaz d'échappements.

A syngas compositional database with focus on trace impurities was established. For this work, ammonia (NH3) and benzene (C6H6) effects on cell growth, enzymatic activities of hydrogenase and alcohol dehydrogenase (ADH), and product formation were studied. NH3, after entering media, will be converted rapidly to NH4+, which will raise the total osmolarity of the media. NH3, as a common nutrient for the cell growth, is not the real culprit for cell growth inhibition. In essence, it is the high osmolarity resulting from the accumulation of NH4+ in the media which disrupts the normal regulation of the cells. It was concluded that at NH4+ concentration above 250 mM, the cell growth was substantially inhibited. However, P11 cells used in this study can likely adapt to an elevated osmolarity (up to 500 mM) although the mechanism is unknown. It was also found that higher osmolarity will eventually lead to higher ethanol per cell density. In conclusion, NH3 needs to be cleaned out of syngas feeding system. The realistic C6H6 concentration in the media coming from a gasifier was simulated in bioreactors and was measured by a GC/MS. The most realistic C6H6 concentration in the media was around 0.41 mM (upper limit 0.83 mM). However, five elevated concentrations of 0.64, 1.18, 1.72, 2.33, and 3.44 mM were doped into the media. It was found that at 3.44 mM cell growth and ethanol production were significantly affected. However, there was only negligible adverse effect on cell growth and ethanol production at 0.41 mM, which is the expected concentration in bioreactors exposed to syngas. Therefore, it is unnecessary to remove C6H6 from the gas feeding stream. A kinetic model for hydrogenase activity that included inhibition effects of NH4+ and C6H6 was developed. Experimental results showed that NH4+ is a non-competitive inhibitor for hydrogenase activity with KNH4+ of (649 ± 35) mM and KH2 of (0.19 ± 0.1) mM. This KH2 value is consistent with those reported in literature. C6H6 is also a non-competitive inhibitor but a more potent one compared to NH4+ (KC6H6=11.4 ± 1.32 mM). A KH2 value of (0.196 ± 0.022) mM is also comparable with literature and also with the NH4+ study. At a realistic C6H6 concentration of 0.41 mM expected in bioreactors exposed to syngas, hydrogenase activity is expected to be reduced by less than 5%. Forward ADH activity was not adversely affected up to 200 mM [NH4+].From the current work, NH3 should be targeted for removal but it is not necessary to remove C6H6 when designing an efficient gas cleanup system.

The study in formation and evolution of sprays is essential for developing more detailed physical models and new injection strategies for direct injection internal combustion engines. In the present work, the sprays from a multi-hole injector are evaluated in an effort to characterize the effects of the spray development in a constant surrounding air flow. These interactions are studied in terms of the air turbulence characteristics, the inlet air mass flow and the fuel injection pressure. Ethanol sprays are injected in a constant-flow chamber. The apparatus purpose is to isolate the experiment from the fluid flow properties intrinsic to engine operations, such as instabilities and moving walls. The factors that affects the air-spray interactions were assessed with the air velocity fields in the presence of the ethanol spray. The two-phase particle image velocimetry technique was enhanced to allow measuring in the required experimental conditions. In all conditions, the interaction is based in a pressure gradient formed between the inner and outer regions of the spray. The results indicates a different mechanism when compared to quiescent conditions. The recirculation vortex at the spray border is present only in the initial injection stages. However, the end of injection transient, an instability initiated with the injector needle closing, is still present for these conditions. The interaction mechanism accelerates the velocity distributions towards the spray main boundary. The experiments indicate that the increase of the air mass flow modifies the air penetration velocity but without altering the interaction mechanism characteristics. Higher injection pressures suggests a lower degree of air interaction at the initial instants of the spray development. Turbulent intensity distributions are calculated for the air flow during the injection event. The distributions indicate that the sprays attenuate the turbulent intensity in all conditions, consistent with the observations of the velocity fields. To assess the effects of air turbulence, sets of interchangeable perforated plates are used to limit the integral scales of turbulence. The spectrogram analyses indicate turbulence is reduced not only in the integral scales, but also in all the measured frequency scales. The inlet turbulence integral scales of the air flow have little influence in the spray development. In the turbulence field, the power levels at the end of injection were similar regardless of the inlet turbulence integral scales.
O estudo da formação e evolução dos sprays é essencial para o desenvolvimento de modelos físicos mais detalhados e novas estratégias de injeção para motores de combustão interna de injeção direta. No presente trabalho, os sprays de um injetor multi-furos são avaliados em um esforço para caracterizar os efeitos do desenvolvimento do spray em fluxo de ar constante. Estas interações são estudadas em termos de características de turbulência do ar,do fluxo mássico de ar e da pressão de injeção de combustível. Sprays de etanol são injetados em uma câmara de fluxo constante. O objetivo do aparato é isolar o experimento de propriedades do escoamento intrínsecas ao funcionamento de motores de combustão interna, tais como instabilidades e geometrias móveis. Os fatores que afetam as interações de arspray foram avaliados com os campos de velocidade do ar obtidos na presença de spray. A técnica de velocimetria por imagem de partículas de duas fases foi aprimorada para permitir a medição nas condições experimentais. Em todas as condições, a interação é baseada em um diferencial de pressão formado entre as regiões interna e externa do spray. Os resultados indicam um mecanismo diferente quando comparado com condições quiescentes. O vortex formado na fronteira do spray é observado apenas nos estágios iniciais de injeção. No entanto, o transiente de fim de injeção ainda está presente para essas condições. O mecanismo de interação acelera as distribuições de velocidade em direção à fronteira do jato. Os experimentos indicam que o aumento do fluxo de massa de ar modifica a velocidade de penetração do ar, mas sem alterar as características do mecanismo de interação. Distribuições de intensidade turbulenta são calculadas para o fluxo de ar durante o evento de injeção. As distribuições indicam que os sprays atenuam a intensidade turbulenta em todas as condições, consistente com as observações dos campos de velocidade. Para avaliar os efeitos da turbulência do ar, conjuntos de placas perfuradas intercambiáveis são utilizadas para limitar as escalas integrais de turbulência. As análises do espectrograma indicam que a turbulência é reduzida não apenas nas escalas integrais, mas também em todas as escalas de freqüência medidas. Estas escalas integrais de turbulência do fluxo de ar de entrada têm pouca influência no desenvolvimento do spray. No campo de turbulência, os níveis de potência ao final da injeção foram semelhantes, independentemente das escalas integrais de turbulência de entrada.

O propósito do presente estudo é investigar a formação de preços do etanol hidratado no mercado de combustíveis do país. Esta pesquisa busca identificar como se forma o preço do etanol hidratado no mercado interno. A concepção teórica parte da compreensão da formação de preços abrangendo custos, economia de escala, fatores mercadológicos, econômicos e sociais na formação de preços. Em seguida, é realizada a contextualização do combustível etanol no mercado interno, como se caracteriza sua demanda e oferta, suas tecnologias e seus principais propulsores na difusão do mercado de combustíveis. Complementa-se com a caracterização do mercado internacional do combustível etanol e com os regulamentos ambientais existentes. Integrando-se as abordagens teóricas com a investigação realizada no setor de combustível etanol. O trabalho prossegue com a metodologia investigativa de atributos interno e externo para formar preços, o que motivou a escolha de uma metodologia baseada em estudos qualitativos e quantitativos, nos quais um complementa o outro em sua análise. Apresentando-se uma metodologia do tipo descritiva, exploratória e explicativa, a pesquisa proporciona reflexões e compreensão do mercado de etanol, que por meio de variáveis qualitativas preditivas, possibilita com o método quantitativo, explicar quais variáveis são significativas na formação dos preços praticados na revenda por meio do modelo de regressão linear múltiplo. Nesta etapa evidencia-se a contribuição em inferir quais variáveis explicam a formação de preços. De maneira secundária, a ferramenta estatística de Análise da Variância (Anova), possibilita identificar a vantagem do preço do etanol hidratado em relação à gasolina C no mercado interno. Pela regressão linear múltipla os resultados mostraram que os preços são formados significativamente pelos preços pagos ao produtor, distribuidora e custos de produção. Pela Anova, os resultados comprovaram também que a região Centro-Oeste foi a única que consolidou a vantagem do uso do etanol hidratado. Para ambos os resultados há reflexões explicativas que norteiam as razões e induzem predições acerca da formação de preços. Nesse sentido, uma reflexão estendida dos resultados permitiu analisar que a vantagem do uso do etanol hidratado na região Centro-Oeste, decorre das variáveis frota, bases de distribuição, tributos, produção e número de usinas produtoras. Com relação aos preços pagos ao produtor, distribuidora e custos de produção como principais variáveis explicativas na formação de preços, há evidências relativas por outras variáveis, que por mais que tenha sido apresentado coeficiente linear baixo, estes possuem relação causal, se complementados com a análise qualitativa, os quais, oferta, demanda, tributos e sazonalidade são, por exemplo, fatores que norteiam e dão complexidade à formação do preço
The purpose of the current study is to investigate the formation of the hydrated ethanol prices in the combustible market of the country. This research seeks to indentify how it is formed the price of the hydrated ethanol in the internal market. The theoretical conception comes from the comprehension of the prices formation involving costs, scale economy, market, economic and social factors in the price formation. Following, it is done the contextualization of the ethanol combustible in the internal market, as it is characterized its demand and offer, its technologies and its main propellers in the diffusion of the combustible market. It is complemented with the characterization of the international market of the ethanol combustible and with environment regulations existent. Integrating itself to the theoretical approach with the investigation done in the ethanol combustible sector. The work follows with the methodology investigated from internal and external attributes to the formation of the prices, what motivated the choice of a methodology based in qualifying and measurable studies, in which one complements the other in its analysis. Presenting a methodology of the descriptive, exploratory and explicative type, the research provides reflection and comprehension of the ethanol market, which by means of predictable qualitative variables, makes possible the quantitative method, explain which variable are significant in the formation of the prices practiced in the reselling by means of pattern of multiple linear regression. In this stage it is evidenced the contribution in inferring which variable explain the prices formation. In a secondary way, the statistic tool of Analysis of Variance (Anova), makes possible identify the advantage of the hydrated ethanol price in relation to the gasoline C in the internal market. By the multiple linear regression the results showed that the prices are formed significantly by the prices paid to the producer, distributor and production costs. By the Anova, the results prove also that the Center-West region was the only one that consolidated the advantage of the hydrated ethanol usage. For both the results there are explainable reflections that guide the reasons and induct predictions about the prices formation. In this way, an extended reflection of the results permitted to analyze that the advantage of the hydrated ethanol usage in the Center-West region, occurs from variable fleet, distribution basis, tributes, production and number of producer mill. In relation to the prices paid to the producer, distributor and production costs as main explainable variable in the prices formation, there are evidences related by other variables, which for more that have been presented low linear coefficient, there ones have casual relation, if complemented with the qualitative analysis, the ones which, offer, demand, tributes and seasonality are, as examples, factors that guide and give the complexity to the price formation

Os processos de conversão de energia tendem a considerar cada vez mais restrições econômicas e ambientais, tornando-se necessário o entendimento da interação entre combustão e turbulência. Esta tese tem como objetivo o desenvolvimento de soluções numéricas para chamas difusivas de metanol e etanol, sob forma de um jato turbulento considerando a formação de NO. Como resultado, obteve-se um mecanismo reduzido de 16 passos para combustão de metanol e outro de 21 passos para etanol, mediante aplicação de análise de sensibilidade para o mecanismo detalhado de Marinov (1999). Estes mecanismos reduzidos foram empregados na simulação, e os resultados foram satisfatórios quando comparados com valores encontrados na literatura. Para determinação da geração de NO na chama, empregou-se o mecanismo de Zel’dovich. Devido a cinética de formação de NO por este mecanismo ser consideravelmente mais lenta do que a taxa de oxidação do combustível principal, foi possível tratar os dois mecanismos separadamente. Os resultados obtidos para formação de NO comparam favoravelmente com dados da literatura.
The energy conversion processes increasingly tend to consider the economical and environmental constraints, making it necessary to understand the interaction between combustion and turbulence. This thesis aims the development of numerical solutions for diffusion flames of methanol and ethanol in the form of a turbulent jet, considering the formation of NO. As a result, a reduced mechanism of 16 steps for methanol combustion and another of 21 steps for etanol combustion was obtained by applying a sensitivity analysis to the detailed mechanism of Marinov (1999). These reduced mechanisms were used in the simulation, and the results were satisfactory when compared with data found in the literature. In order to determine the NO generation in the flame, the Zel’dovich mechanism was applied. Because the NO kinetics formation by this mechanism is considerably slower than the oxidation rate of the main fuel, it was possible to treat the two mechanisms separately. The results obtained for NO formation compare favorably with literature data.

Les conditions physiques et chimiques des premières étapes de la formation stellaire sont propices à la formation de molécules complexes organiques à base de carbone, oxygène et azote qui pourraient être les précurseurs des espèces prébiotiques découvertes dans les météorites. Des études suggèrent que cette complexité démarre avec des réactions chimiques sur les grains interstellaires et l'évaporation des espèces formées dans la région chaude de l'étoile en formation. Par ailleurs le lancement de l'Observatoire Spatial Herschel (HSO) et la mise en route de l'interféromètre ALMA (Atacama Large Millimeter Array), permettent des études inédites à haute résolution spectrale et/ou spatiale dans les domaines submillimétriques et du térahertz. Ainsi de nombreuses molécules peuvent être étudiées avec une sensibilité inégalée sur une large gamme spectrale. Cependant, les données spectroscopiques précises permettant d'identifier les molécules complexes qui nous intéressent sont parfois manquantes principalement à cause des difficultés liées à la mesure et à l'analyse de leurs spectres de laboratoire. Durant cette thèse je me suis intéressée plus particulièrement aux isotopologues des molécules complexes, aussi bien d'un point de vue spectroscopique qu'astrophysique. L'étude des abondances de ces isotopologues (deutérés, 13C. . . ) dans le milieu interstellaire peut fournir des informations visant à comprendre les chemins réactionnels qui conduisent à la complexité moléculaire et ainsi contribuer à contraindre leur formation afin de déterminer si elle a lieu en phase gazeuse ou sur les grains. Dans une première partie, je présenterai les notions essentielles à la compréhension et la cohésion des deux composantes (spectroscopie de laboratoire et observations astrophysiques) ainsi que les différents outils utilisés lors de ces études; j'introduirai alors les différents types d'observations en radioastronomie. Dans une seconde partie, je développerai les études menées sur les isotopologues de deux molécules complexes organiques (l'éthanol 13C et le glycolaldéhyde deutéré) ayant un intérêt astrophysique. Ces études ont débuté d'un point de vue spectroscopique, avec (i) les mesures du spectre en laboratoire, et (ii) la détermination des paramètres caractéristiques des différents isotopologues. Ces travaux ont mené à la réalisation d'un spectre synthétique, ayant pour but de réaliser une identification dans le milieu interstellaire (MIS). Ces études ont continué d'un point de vue astrophysique avec la recherche des molécules étudiées en laboratoire dans des régions de formation stellaire. J'ai, dans un premier temps, effectué des tentatives de détection à partir des relevés spectraux existants: ceux-ci ont permis d'établir des limites de détection de nos molécules et ont mis en évidence quelques raies qui pourraient correspondre aux espèces recherchées. Puis j'ai réalisé mes propres observations afin de tenter de confirmer la détection et de montrer de possibles différences d'abondance entre les isotopomères. Je terminerai en ouvrant sur les perspectives pour des observations futures et pour des développements ultérieurs, basés sur ce travail
The physical and chemical conditions of the first stages of star formation are favourable for the formation of complex organic molecules containing carbon, oxygen, and nitrogen which could be the precursors of the prebiotic species discovered in meteorites. Studies suggest that this complexity begins with chemical reactions on interstellar grains and the subsequent evaporation of the species formed on these grains in the warm core region of the forming star. Recently, the Herschel Space Observatory (HSO) and the ALMA interferometer have begun to make available new sensitive high spectral and/or high spatial resolution studies in the submillimetre and terahertz domains. Thus many molecules can now be studied with unequalled sensitivity over a wide spectral range. However, accurate spectroscopic data necessary to identify some of the complex molecules which interest us are missing because of the difficulties in measuring and especially in analysing their laboratory spectra. During my thesis I have been particularly interested in the 13C and deuterated isotopologues of complex molecules, both from a spectroscopic and from an astrophysical point of view. The study of the abundances of these isotopologues in the interstellar medium could supply information to help us to understand reactions pathways which lead to molecular complexity and determine which reaction take place in the gas phase and which on grains. First of all, I will present the notions useful to understand this work linking molecular spectroscopy and radioastronomy as well as the tools used; also I will introduce the different instruments available for observations. Secondly, I will detail the work carried out on 13C-substituted ethanol and deuterated glycolaldehyde, two complex organic molecules of astrophysical interest. The work involved laboratory measurements and analysis leading to a set of molecular parameters used to subsequently produce predictions of astrophysical spectra for the studied species, under the physical conditions of the astrophysical objects of interest. These synthetic spectra were compared with existing spectral surveys of star-forming regions thus identifying several candidate lines that were unfortunately too limited to prove detection; they also allowed the estimation of maximum abundances for all species. Then I will describe our own observations taken with the aim of confirming the detections and showing possible abundance differences between different isotopomers of each isotopologue. Finally I will give perspectives for future observations and further developments based on this work

L'épuisement des réserves pétrolières et l'augmentation de la concentration du gaz à effet de serre CO2 sont les deux principaux problèmes connus liés à l'utilisation des carburants fossiles. Les biocarburants apparaissent comme un des moyens permettant à la fois une diminution de la dépendance au pétrole et une réduction de l'impact néfaste des moteurs automobiles sur l'environnement. Les biocarburants sont en effet considérés comme une source d'énergie renouvelable. L'objectif de cette thèse était de développer et valider les modèles cinétiques de combustion des composés oxygénés de biocarburants : l'éthanol, les biocarburants de deuxième-génération des familles du furane (furane, 2-méthylfurane, 2,5-diméthylfurane), du tétrahydrofurane (tétrahydrofurane, 2-méthyltétrahydrofurane) et le tétrahydropyrane, en utilisant les nouvelles données obtenues en flamme laminaire pré-mélangée à basse pression. De 20 à 60 produits ont été quantifiés par chromatographie en phase gazeuse et identifiés par couplage avec la spectrométrie de masse. Les résultats obtenus ont ensuite été utilisés pour analyser les voies de consommation des réactifs et de formation des produits, surtout pour les polluants, dans le but de mieux comprendre la chimie de la combustion de ces biocarburants. Ce rapport comprend 5 chapitres et une conclusion. Le premier chapitre présente une revue bibliographique des travaux antérieurs sur l'oxydation de l'éthanol et des éthers cycliques. Dans le second chapitre, le dispositif expérimental est décrit, en détaillant en particulier les nouveaux développements. Enfin les chapitres 3, 4, 5 présentent les résultats de l'étude de la combustion des composés étudiés
The decrease of petroleum reserves and the increase of concentration of greenhouse gas CO2 are the two major known problems related to the use of fossil fuels. Bio-fuels appear as a means allowing a decrease of the dependence on fossil fuels and a reduction of the harmful impact of engine on the environment. Bio fuels are considered as a source of renewable energy. The aim of this thesis was to develop and validate experimentally the high temperature kinetic models for the combustion of oxygenated compounds of bio-fuels: ethanol, second-generation bio-fuels of families of furan (furan, 2-methylfuran, 2,5-dimethylfuran), of tetrahydrofuran (tetrahydrofuran, 2 methyltetrahydrofuran), and tetrahydropyran, using new data obtained in laminar premixed low-pressure flame. About 20-60 products were quantified by gas chromatography and identified using mass spectrometry. The results obtained were then used to analyze the consumption pathways of fuels and the formation pathways of products, especially for pollutants, in order to better understand the combustion chemistry of these bio-fuels. This thesis report includes 5 chapters and a conclusion. The first chapter presents a review of the major works already published in the literature for the oxidation of ethanol and cyclic ethers. In the second chapter, the experimental setup of laminar premixed flame with the analytical techniques is described, detailing in particular new developments. Eventually, chapters 3, 4, 5 present the experimental and modeling results of the study of the combustion chemistry of the compounds studied

L'incorporation d'ingrédients bioactifs dans les produits alimentaires est en plein essor. Il a été démontré que ces ingrédients possèdents des propriétés biologiques importantes permettant l'amélioration de la santé et la prévention des maladies dites de civilisations. Toutefois, l'ajout de ces molécules bioactives est dans la plupart des cas impossible ou insuffisant, du fait que ces composés ne sont que peu solubles dans les systèmes aqueux et présentent i) une stabilité limitée contre les dégradations chimique ou physique, ii) une libération non contrôlée ou une faible biodisponibilité. Face à ces contraintes, les recherches actuelles visent à élaborer des systèmes d'encapsulation efficaces pour résoudre ces problèmes de formulation. Dans notre étude, deux représentants d'ingrédients alimentaires ont été choisi : le sesquiterpène nérolidol (Ner) et le flavonoïde quercétine (Quer) présentant diverses activités biologiques mais des propriétés physicochimiques problématiques. Ainsi, l'objectif de notre travail a été d'encapsuler ces composés actifs dans les cyclodextrines (CDs), les liposomes conventionnels (LCs) et le système mixte cyclodextrine-liposomes (DCLs) afin de développer des systèmes naturels et éco-compatibles ayant des applications potentielles dans les domaines alimentaires.Trois axes ont été abordés. Le premier axe a porté sur la préparation et la caractérisation des complexes d'inclusion CD/invité en solution et à l'état solide. Les techniques de spectroscopie UV-visible, Chromatographie Liquide à Haute Performance (CLHP), Carbone Organique Total (TOC), ¹H Résonance magnétique nucléaire (RMN), 2D ROESY RMN et de la modélisation moléculaire ont été utilisées comme outils pour la caractérisation des complexes obtenus. Des études de phase de solubilité ont également été réalisées. Le deuxième axe a porté sur la préparation des LCs et DCLs par la méthode d'injection éthanolique et leur caractérisation. Les préparations des LCs encapsulant la quercétine a été réalisée à partir de phospholides naturels de jaune d'oeuf (Lipoid E80) et de soja insaturés (Lipoid S100) ou saturés (Phospholipon 90H) afin d'étudier l'effet de la composition lipidique que les caractéristiques des liposomes. La formulation optimale a été par la suite appliquée pour préparer des LCs encapsulant le nérolidol et des DCLs encapsulant les deux molécules. Ce dernier est produit par l'incorporation des complexes d'inclusion HP-β-CD/Ner (à différents rapport moléculaire CD:Ner) et SBE-β-CD/Quer dans la cavité aqueuse des liposomes. Le dernier axe a été orienté vers l'évaluation de l'effet de l'encapsulation sur les propriétés physicochimiques du nérolidol et de la quercétine (libération in vitro, photostabilité, stabilité dans les milieux gastro-intestinales, stabilité de stockage) et leur activité antioxydante. Les résultats ont montré que les CSs ont été capables d'encapsuler les composés actifs étudiés, d'augmenter leur solubilité, leur photostabilité ainsi que leur activité antioxydante. En outre, les liposomes à base de Lipoid E80 ont été trouvés majoritairement de taille nanométrique et ont conféré aux molécules une efficacité d'encapsulation (EE) élevée ainsi qu'une meilleure stabilité par rapport aux deux autres types de liposomes. De plus, la taille des DCLs ains que leur EE ont été prouvées dépendante du rapport moléculaire CD:invité. Par rapport aux LCs, les DCLs ont assuré une libération prolongée du nérolidol, ont augmenté la photostabilité des composés et la stabilité de la quercétine dans les milieux biologiques. Les résultats de cette étude suggèrent que ces systèmes peuvent être considérés comme outils prometteurs pour l'optimisation des formulations alimentaires incorporant le nérolidol et/ou la quercétine
Phytochemicals are widely distributed secondary metabolites, divided into three major classes : terpenoids, flavonoids and alkaloids. They are shown to possess important biological properties such as anti-cancer, anti-inflammatory and anti-microbial properties. Therefore, increasing the use of these bioactive molecules in food products may reduce the risk of widespread diseases referred to as "diseases of civilization". However, their low solubility, susceptibility to degradation and their rapid release reduce their bioavailability in the human body and thus their biological effect. To solve the aforementioned physicochemical drawbacks, encapsulation systems were developed to allow the incorporation of phytochemicals in food. In this study, two food ingredients : the sesquiterpene nerolidol and the flavonol quercetin were selected du to their potent biological activities but their problematic physicochemical properties.Therfore, the aim of this work was to encapsulate these molecules into cyclodextrins (CDs), conventional liposomes (CLs) and the double systeme drug-in-cyclodextrin-in-liposomes (DCLs), in order to develop nztural and biocompatible formulations that may find applications in food fields. This project was built around three main research axes. The first part dealt with the preparation and the characterization of CD/guest inclusion complexes both in solution and in solid state. Characterizations were performed with UV-visible spectroscopy, High Performance Liquid Chromatography (HPLC), Total Oragnic Carbon (TOC), ¹H NMR, 2D ROESY NMR, and molecular modeling. These investigations were complemented with phase solubility studies.The second axis addressed the preparation of CLs ans DCLs by ethanol injection method and characterization of the vesicles. CLs encapsulating quercetin were prepared from three different types of phospholipids (Lipoid E80, Lipoid S100, Phospholipon 90H) in order to study the effect of lipid composition on the characteristics of liposomes. The optimal formulation was then selected to prepare nerolidol loaded-CLs and DCLs encapsulating the two compounds. HP-β-CD/Ner (at different CD:Ner molar ratios) and SBE-β-CD/Quer inclusion complexes were used as the aqueous phase in the DCL system. The last part focused on the effect of encapsulation on the physicochemical properties of nerolidol and quercetin (in vitro release, photostability, stability in gastro-intestinal fluids, storage stability) and their antioxidant activities. Results demonstrated that CDs could successfully encapsulate bioactive compounds, enhance their solubility , photostability and antioxidant activity. Furthermore, Lipoid E80-liposomes were nanometric in size, exhibited a high entrapment efficiency and higher stability in comparison to the other formulations. Moreover, CD:guest molar ratio influenced the size of DCLs and their encapsulation efficiency. When compared to CLs, DCLs extended the release of neridol, enhanced the photostability of both compounds ans increased the stability of quercetin in biological fluids. These results could be considered as a promising tool to achieve an optimized and efficient formulation incorporating nerolidol and quercetin in food industry

Au Brésil, la canne à sucre sert de matière première à la fabrication de sucre, de carburant, et d’électricité. Ce modèle industriel a permis au pays d’ériger en avantage compétitif sa productivité en biomasse. Il a été promu en Afrique mais la majorité des projets d’agroénergies y a été un échec. Ce constat pose la question de l’intérêt du modèle au Brésil et du rôle des agroénergies dans une stratégie de développement. Notre analyse pose le « modèle brésilien » comme Système d’Innovation Technologique - le SIT de la canne - dont nous analysons la trajectoire de long terme afin d’en saisir les déterminants de succès et d’échec ainsi que le rôle socio-économique historique. Il se structure depuis la fin du XIXème et sert une stratégie de diversification des marchés de la canne à sucre par l’importation, l’adaptation et la diffusion des technologies nécessaires à l’essor de ces nouveaux marchés. La filière biocarburant a en particulier nécessité de créer un système technologique alternatif. Le soutien public a été déterminant dans l’évolution du SIT de la canne, façonnée par les crises sociales et économiques du pays. Par le SIT de la canne, le Brésil a pu former son capital humain à la valorisation du capital naturel, cela lui permet aujourd’hui d’expérimenter une conversion agroécologique du mode de culture, afin de régénérer le capital naturel sol.Notre analyse du modèle brésilien nous permet de préciser la fonction des agroénergies dans une stratégie de développement : elles sont avant tout un outil de soutien à l’économie agricole. Au regard de cela nous analysons les facteurs d’échecs des projets africains de jatropha-énergie et formulons une proposition pour la structuration d’un SIT des agroénergies adapté aux enjeux de développement de l’Afrique de l’Ouest, que nous proposons d’adosser à la filière oléagineuse
In Brazil, sugar cane is used as a raw material for the production of sugar, fuel, and electricity. This industrial model has enabled the country to build a competitive advantage on the biomass productivity of its soils. It has been promoted in Africa but the majority of African bioenergy projects have been a failure. This raises the question of the interest of the model in Brazil, of the role of bioenergy in a development strategy.The Brazilian model is a Technological Innovation System, the sugar cane TIS, which we analyze in the long term. Since the end of the 19th century, it has been structured to import, adapt and spread technologies in order to diversify sugar cane markets. The biofuel sector required the creation of an alternative technological system, financed by the State through the Proalcool Program (1975 to 1985); Created to absorb the surpluses of the sugar sector and for the energy security of the country. Public support was key in the evolution of the TIS, forged in the wake of the country's social and economic crises. The sugar cane TIS has enabled Brazil to train its human capital in the valorization of natural capital, which enables it today to experiment a new change : the agroecological conversion of the cane cultivation model, that would allow regenerating the Natural Capital soil. Based on our analysis of the Brazilian model we formulate an analysis of the factors of failure of the African jatropha biofuel projects and make a proposal for the structuring of a biofuel TIS adapted to West Africa stakes of development, which we suggest to back up to the oilseed chain
No Brasil, a cana-de-açúcar é utilizado como matéria-prima na fabricação de açúcar, combustível e eletricidade. Este modelo de negócio tem permitido ao país para transformar a produtividade de biomassa de seu solo em uma vantagem competitiva. Ele foi promovido na África, mas a maioria dos projetos de agroenergia africanos houve uma falha. Isso levanta a questão do interesse do modelo no Brasil, bem como o papel da bioenergia em uma estratégia de desenvolvimento. O modelo brasileiro é um Sistema de Inovação Tecnológica, o SIT da cana, que analisamos a longo prazo. Ele é estruturado desde o final do século XIX para importação, adaptação e difusão de tecnologias afim de diversificar os mercados de cana. O setor do etanol combustível tem necessidade de um sistema tecnologia alternativa, financiado pelo governo através do Programa Proálcool (1975-1985); ele foi criado para absorver os excedentes do sector do açúcar e para a segurança energética do país. O apoio público tem sido fundamental para a evolução do SIT, foi forjada pelas crises sociais e económicas do país. Hoje o SIT da cana-de-açúcar experimenta um modelo de produção agroecológica para o cultivo da cana, ele deveria ser capaz de regenerar o capital natural. Nossa análise do modelo brasileiro nos permite fazer uma análise dos fatores de não-sucesso dos projetos africanos de produção de biocombustível de jatropha. Nós formular uma proposta de estruturação de um SIT da agroenergia Oeste Africano adaptado às questões de desenvolvimento locais, propomos a ser associado ao setor oleaginosa

The alkylation of benzene with ethane was studied at 370 oC over two Pt-containing ZSM-5 catalysts with SiO2/Al2O3 ratios of 30 and 80. While the benzene and ethane conversion decreased with time-on-stream for the PtH-ZSM-5(30) catalyst, the PtH-ZSM-5(80) catalyst demonstrated a stable performance. The deactivation of the PtH-ZSM-5(30) catalyst was found to be more significant, when compared to the PtH-ZSM-5(80) catalyst as a result of differences in the formation of coke. Results from gas sorption and x-ray diffraction experiments showed that coke is preferentially formed within the channel segments of the PtH-ZSM-5(30) catalyst as opposed to coke deposition on the outside surface of the PtH-ZSM-5(80) crystallites, subsequently blocking entrance to the zeolite channels.
The location of the coke deposition was found to affect the product selectivity of the two PtH-ZSM-5 catalysts. The accessibility functions, derived from nitrogen and argon sorption data, suggested that, with prolonged time-on-stream, the coke molecules build up from the middle of the zeolite crystallites outwards towards the surface, as the reaction was carried out over the PtH-ZSM-5(30) catalyst. Partial blockage of the internal pore structure of the PtH-ZSM-5(30) catalyst decreased the diffusion length within the crystallites. In contrast to the typical effect of coking, where the selectivity of para- isomers would be enhanced with coke deposition, the effect of the reduction in the diffusion length of the PtH-ZSM-5(30) crystallites is consistent with the decreasing para-selectivity of the diethylbenzene (DEB) isomers with time-on-stream.
n investigation of the causes of coke locations was conducted, and the results suggested that, the spatial distribution of Pt metal was responsible for the different locations of coke observed. Surface reactions initiated coking in the intercrystalline region of the PtH-ZSM-5(80) catalyst, as the Pt particles on the surface of the PtH-ZSM-5(80) crystallites increased the difficulty of access for reactants to the interior of the crystallites. Within the PtH-ZSM-5(30) catalyst, ethane dehydrogenation and benzene alkylation took place in the micropore network as a result of preferential intracrystalline deposition of Pt metal. Further conversions on the active sites within the PtH-ZSM-5(30) crystallites thus lead intracrystalline coking.

The theory of the abyssal abiotic petroleum origin considers oil and natural gas to begenerated in the Earth’s upper mantle. Hydrocarbons migrate further through the deep faults into the Earth’s crust, where they can form oil and gas deposits in any kind of rock in any kind of structural position. Until recently one of the main obstacles for further development of this theory has been the lack of the data covering processes of generation and transformations of hydrocarbons. Experimental data, presented in this thesis, confirms the possibility of hydrocarbons formation from mantle inorganic compounds (water, Fe, CaCO3 or graphite) at temperature and pressure of the upper mantle (1500 K and 5 GPa). Experiments were carried out in CONAC high pressure device and multianvil apparatus BARS. Compositions of received gas mixtures were similar to natural gas. Quantity of hydrocarbons depended on the cooling regime of reaction mixture under pressure. Slow cooling favored higher quantity. We found that donor of carbon (CaCO3 or graphite) determines formation of “dry” (methane-rich) gas or “wet” (light hydrocarbons-rich) gas. Experiments in laser-heated diamond anvil cells showed that methane and ethane partially react under upper mantle thermobaric conditions (2-5 GPa, 1000-1500 K) to form mixture of hydrocarbons: methane, ethane, propane and n-butane – main compounds of natural gas. Similarity of final product mixture obtained from methane and ethane means thermodynamic stability of hydrocarbons in the thermobaric conditions of the upper mantle and equilibrium character of the observed processes.
QC 20101203

碩士
元智大學
化學工程與材料科學學系
104
In this study, the prepared catalysts for the ethanol dehydration in a fixed bed reactor was obtain more active acidic catalyst under the reaction conditions at lower temperatures. This study explored the experimental conditions, including different type catalysts (ZSM-5 zeolite catalyst by using the impregnation method modified with phosphorous and lanthanum, active aluminum oxide (γ-Al2O3)). With examined the weight hourly space velocity, water content of ethanol, and reaction temperatures. Characterization of the catalyst was carried out with BET, NH3-TPD, SEM, TGA, XPS and XRD. The experimental results show that when the concentration of ethanol is 95%, the yield and selectivity of ethylene can be achieved 98.5% and 100%, respectively, using ZSM-5 zeolite catalyst by dealuminization at 220 °C. When the concentration of ethanol is 20%, the yield and selectivity of ethylene can be achieved 94.3% and 94.4%, respectively, using ZSM-5 zeolite catalyst by phosphorous-modified at 240 °C. Both of these catalysts are the best among all prepared catalysts.

碩士
元智大學
化學工程與材料科學學系
96
This study employed the sol-gel method to evaluate film formation feasibility of the TEOS/ethanol/water tri-component system. The pH of water was adjusted by HCl or NH4OH. After the precursor (TEOS) was hydrolyzed and condensed to a certain extent, the formulation was applied onto glass substrate. The feasibility of film formation under acid and base condition with different water/silicon ratio was investigated. After the applied coating was dried, SEM was used to observe the morphology of surface of the glass substrate before and after curing. Besides, FTIR was used to observe the microscopic change of each liquid formulation for a period of time. The result showed that the recipe was applicable under low pH value with the ratio of water/silicon ranging from 1 to 4. At high ratio of water/silicon, the formulation cannot spread out on the substrate. At high ratio of water/silicon, the recipe can not be applied. The FTIR results confirmed that different concentration of catalyst and water/silicon ratio resulted in different condensation product. Different condensation products affects the feasibility of film formation for each recipe. Under condition of pH2 and r=1, FTIR result indicated the existence of linear and cyclic species. Linear species were diminished due to their gradual cyclization into cyclic species with time. At high pH value, increasing water/silicon ratio, r, resulted in particle-based films. Finally, at intermediate pH value ranging from 4 to 7, FTIR results showed similar spectra, while the SEM result also showed similar film surface morphology.

No
To gain a better understanding of how ethanol affects biological membranes, we have performed a series of atomic-scale molecular dynamics simulations of phospholipid membranes in aqueous solution with ethanol, whose concentration was varied from 2.5 to 30 mol % (lipid-free basis). At concentrations below the threshold value of ~12 mol % (30.5 v/v %) ethanol induces expansion of the membrane, accompanied by a drop in the membrane thickness as well as disordering and enhanced interdigitation of lipid acyl chains. These changes become more pronounced with increase in ethanol concentration, but the bilayer structure of the membrane is maintained. Above the threshold concentration the appearance of multiple transient defects in the lipid/water interface eventually gives rise to desorption and assembly of some of the lipids into non-bilayer structures within the membrane interior. These structures, being small and irregular, resemble inverted micelles and have a long-lived character. Furthermore, formation of the non-bilayer structures is accompanied by mixing of lipids that belong to the opposite membrane leaflets, thereby leading to irreversible changes in the membrane structure. Remarkably, this observation of the formation of non-bilayer structures within the membrane interior, being in good agreement with experimental data, is found to be robust with respect to both the simulation conditions (the system size and the presence of salt) and the type of lipids (phosphatidylcholine and phosphatidylethanolamine). We discuss the significance of these non-bilayer structures in relation with the well-known ability of ethanol to promote membrane hemifusion as well as with the possible role of the micelle-like structures as a delivery system for polar solutes and ions. The ethanol-induced "damage" to the bilayer structure also suggests that strong alcoholic beverages (~40 v/v %) might be potentially hazardous to the epithelial tissues of the human body (such as lips, mouth, throat, gullet, and stomach) that come in direct contact with high-concentrations of ethanol.

Thesis (Ph.D.)--University of Alberta, 2010.
Title from PDF file main screen (viewed on July 29, 2010). A thesis submitted to the Faculty of Graduate Studies and Research in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Bioresource and Food Engineering, Department of Agricultural, Food and Nutritional Science, University of Alberta. Includes bibliographical references.

Stable isotope of natural gas hydrates provides useful information of their gas sources. We investigated the isotopic fractionation of gas molecules during the formation of synthetic gas hydrates composed of methane and ethane. The gas hydrate samples were experimentally prepared in a pressure cell and isotopic compositions (δ13C and δD) of both residual and hydratebound gases were measured. δD of hydrate-bound molecules of methane and ethane hydrates was several per mil lower than that of residual gas molecules in the formation processes, while there was no difference in the case of δ13C. Effect of temperature on the isotopic fractionation was also investigated and it was found that the fractionation was effective at low temperature.

碩士
國立屏東科技大學
食品科學系所
97
Maillard reaction（sugar-amine reaction）provides the color and flavor characteristics to foods during heating processes. However, a lot of mutagens or carcinogens also produced in the reaction. Maillard reaction is quite complicated. This study mimics the marinades of meat with the wine. The creatinine/glucose/threonine ethanolic model solution was used to investigate the formation of carcinogenic IQ and IQx compounds during the Maillard reaction. The experimental results showed that the pH value increases with the concentration of ethanol increasing in the model solution. After heating, the pH value of ethanol solution did not have obvious change. However, the pH values of aqueous solution changed significantly after heating. The browning rate increases with the concentration of ethanol and glucose (R2=0.994) in the model solutions. The browning rate is as follows: five carbon sugar> six carbon sugars, aldoses> ketones in the ethanolic solutions. The results also showed that the formation of carcinogenic IQ and IQx compounds demonstrated a lowest yield in 5% ethanol solution after heating. The formation of the carcinogens increases with the rate of browning in the model solutions.