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Les aventures sonores : d’une éthique à une esthétique, par les gestes et concepts des labyrinthes de l’imaginationSablich, Mirko 08 1900 (has links)
La version intégrale de ce mémoire est disponible uniquement pour consultation individuelle à la Bibliothèque de musique de l’Université de Montréal (http://www.bib.umontreal.ca/MU). / Ce mémoire présente les composantes et les résultats des applications d’une démarche de composition musicale basée sur deux approches à la fois complémentaires et indépendantes. L’une concerne une éthique de travail compositionnel qui conduit à de possibles esthétiques sonores, à travers les expérimentations, les questionnements et les observations et recherches des origines d’une pièce. L'autre se rapporte à l'esprit et à l'imagination, à des domaines connexes ou stimuli et à des gestes et concepts proprement musicaux. Les composantes des approches se présentent récursivement et simultanément et tissent un réseau de relations imprévues, chaotiques et ambiguës. Tout au long du processus, l’intuition, contemplative et modératrice, façonne une essence sonore. Deux pièces analysées font preuve des résultats de ces approches. / This thesis presents an approach to music composition based on two processes, which are both complementary and independent of each other, and their application to a musical work. The first process is based on a creative work ethic that involves observation, research of the origins of a piece of music, questioning and experimentation, which ultimately lends itself to create a certain aesthetic. The second process is based on the mind, the imagination, related domains or stimuli, and on musical gestures and concepts. The elements of these two processes can exist simultaneously, and can occur recursively creating a chaotic and ambiguous network of relationships. In this approach, intuition, contemplative and moderate, plays a primordial role in molding the essence of a musical work. Two musical pieces illustrate the validity of such an approach.
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Between Meaning and Essence - Explaining Necessary TruthSchieder-Hestermann, Jakob 16 May 2019 (has links)
Eine Erklärung, warum manche Wahrheiten notwendigerweise wahr sind, sollte verständlich machen, warum es für diese eine Wahrheitsgarantie gibt. Einen interessanten Ansatz für eine solche Erklärung liefert Kants Definition analytischer Wahrheiten als solche, die bereits in einem Begriff enthalten sind. Die notwendige Wahrheit analytischer Sätze kann hier über das Verhältnis ihrer Bestandteile erklärt werden. Diese Erklärung kann jedoch nur der Anfang einer generellen Erklärung von Notwendigkeit sein, denn einerseits sind nicht nur analytische Urteile notwendig, sondern auch andere, andererseits basiert die Erklärung auf einer umstrittenen Theorie von Begriffen. Die Dissertation untersucht nun, ob und wie die Strategie, Notwendigkeit über das Verhältnis zwischen den Bestandteilen von Repräsentationen zu erklären dennoch ausgeweitet und verteidigt werden kann, um zum Beispiel auch a posteriori Notwendigkeiten und essentialistische Urteile zu erfassen. Indem auf die die Referenz-Relation konstituierenden Fakten Bezug genommen wird, wird gezeigt, dass eine solche Erklärung tatsächlich möglich ist. Notwendige Wahrheit ist demnach eine Eigenschaft von wahrheitsfähigen Repräsentationen, die diese aufgrund des Verhältnisses zwischen den für die Wahrheit der Repräsentation nötigen Fakten und den Fakten, die die Referenz der Bestandteile der Repräsentation bestimmen, hat. Stehen diese in einem bestimmten Verhältnis, wird die Wahrheit der Repräsentation garantiert. Nachdem dieser Ansatz auf eine Reihe von Beispielen angewendet wird, zeigen sich interessante Parallelen zu essentialistischen Theorien von Notwendigkeit und es lässt sich zeigen, dass der Ansatz das Verhältnis zwischen Essenzen und Notwendigkeit richtig darstellt und es sogar erlaubt, ein besseres Verständnis davon zu entwickeln, was Essenzen sind. / An explanation of why some truths are necessarily true needs to make intelligible how it is that a truth is guaranteed to be true. The thesis argues that a promising starting point for an explanation of necessity can be found in Kant’s containment-account of analyticity, for it explains how the truth of a judgment is guaranteed by its structure and the relationship between its constituents. This, however, can merely be a starting point for a general explanation of necessary truth, for it is both too narrow, and presupposes a contentious view of concepts. The thesis thus explores how the general strategy, explaining necessary truth by certain relationships between the constituents of representations, can be expanded to cover further necessary truths, for example a posteriori necessities and essentialist claims. It is argued that the explanation can be generalized by focussing on what it is that constitutes reference between representations and the objects they represent as well as how these representations come together to form truth-evaluable representations. Necessary truth, on this account, is a property of truth-evaluable representations which a representation has in virtue of the appropriate relationship between what is required for its truth, and the way in which the reference of its constituents is determined. The appropriate relationship guarantees the truth of the representation. After applying the theory to a range of examples, interesting parallels to essentialist accounts of necessity emerge and it is argued that the proposed explanation gets the relationship between essence and necessity right and may even be used to elucidate what essences are.
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Contribution des composés organiques volatils (COVs) provenant des émissions des véhicules aux aérosols organiques secondaires (AOS) et à la pollution urbaine / Contribution of volatile organic compounds (VOCs) from vehicle emissions to secondary organic aerosol (SOA) and urban pollutionMartinez, Alvaro 29 March 2019 (has links)
Le secteur des transports est fondamental pour le développement économique d'un pays et pour assurer la communication et une bonne qualité de vie. Cependant, le transport routier conduit à une grave dégradation de la qualité de l'air et contribue au réchauffement de la planète. Parmi tous les polluants, les particules fines et ultrafines, émises par les véhicules mais également formées dans l'atmosphère sont considérées toxiques. De nombreuses études montrent que l’exposition chronique aux particules fines favorise le développement de pathologies respiratoires et cardiovasculaires. Les précurseurs gazeux, les principaux mécanismes réactionnels ainsi que les transformations physiques que les Aérosol Organiques Secondaires (AOS) subit dans l'atmosphère restent encore incertains. La présente étude porte principalement sur la caractérisation des polluants primaires émis par les échappements automobiles et les transformations photochimiques des COV / COVI. Les émissions des voitures ont été évaluées à l’aide d’un banc à rouleau au laboratoire de l’IFSTTAR. Les mesures du nombre de particules ont été effectuées directement au niveau de l’échappement. Pour les véhicules GDI, PN0.23 (<23 nm) représentait en moyenne 20- 30% du nombre total de particules émises, alors que pour les voitures diesel, cette fraction était bien inférieure (≈10-15%). Lors des régimes à grande vitesse (autoroutier Artemis) des véhicules diesel, une régénération passive de Filtre à Particules (FAP) a été observée. Les particules émises étaient principalement constituées de suie, de bisulfate et de matière organique. Les particules émises par les voitures essence à injection directe étaient principalement composées de Black Carbon (BC) et de gouttelettes organiques contenant des éléments. Pendant le démarrage à froid, les voitures GDI émettent des concentrations importantes de BC et de matière organique. Les émissions d'hydrocarbures ont également été étudiées. Les véhicules GDI ont émis des concentrations importantes de THC lors du démarrage à froid. Parmi les composés aliphatiques, des composés jusqu’à la C15 ont été identifiés, confirmant l’émission d'hydrocarbures plus lourds par les voitures diesel. La deuxième partie de ce travail consistait à étudier la transformation atmosphérique de certains COV (toluène, naphtalène, cyclohexane, nonane) émis par les véhicules Euro 5 et Euro 6 et à déterminer le potentiel de formation d’AOS de ces composés. Les composés choisis ont été photo-oxydés (seuls et en mélange) dans un réacteur à tube à flux d'aérosol afin de simuler leur vieillissement atmosphérique. Les résultats majeurs suggèrent: (1) des composés aromatiques et des HAP représentent les composés avec le plus fort potentiel de formation d'AOS ; (2) la température a un impact important sur la formation et le rendement d'AOS ; (3) la présence de particules préexistantes a un effet positif sur la formation d'AOS; (4) il a été constaté que la présence des NOx affectaient négativement la formation d'AOS ; (5) la formation d'AOS de mélanges de COV est fortement influencée par la fraction de composé aromatique. Certains des produits identifiés dans la phase particulaire n’ont jamais été signalés auparavant. La dégradation des composés aromatiques en régime de NOx moyen a produit des composés nitro-aromatiques identifiés à la fois en phase gazeuse et en phase particulaire. Cette thèse contribue à enrichir la base de données d’émissions des voitures, encore limitée aux véhicules Euro 5 et Euro 6. La spéciation des composés non réglementés aidera à mieux comprendre le budget atmosphérique d’AOS et les impacts des voitures sur la qualité de l’air. Enfin, l’étude de photoxydation de COV primaires (seuls, mélange et émissions complètes) conduira à une meilleure compréhension de la formation d’AOS / The transport sector is fundamental to the economic development of a country and to ensure communication and a good quality of life. However, road transport contributes significantly to global warming and leads to serious degradation of the air quality. Among all pollutants, fine and ultrafine particles, emitted by vehicles but also formed in the atmosphere are considered as potentially toxic. Many studies show that chronic exposure to fine particles promotes the development of respiratory and cardiovascular diseases. The main gaseous precursors, the atmospheric chemical pathways as well as the chemical composition and the physical transformations that secondary organic aerosol (SOA) undergo in the atmosphere, remain poorly understood. The main aim of this work was on one side to improve the knowledge about primary pollutants emitted from Euro 5 and Euro 6 diesel and gasoline passenger cars and on the other side to investigate the photochemical transformations of the VOCs/IVOCs emitted from these cars. Passenger car emissions have been evaluated on a chassis dynamometer test bench at the IFSTTAR laboratory. Particle number measurements were carried out directly at the tailpipe. For GDI vehicles PN0.23 (< 23 nm) represented on average 20 -30 % of total particle number emitted, while for diesel cars, this fraction was considerably lower (≈10-15%). During high speed regimes (Artemis motorway) of diesel passenger cars Diesel Particulate Filter (DPF) passive regeneration was observed. These periods were characterized by a high particle number concentration; their composition was mainly soot, bisulfate and some organic material. PM emitted from gasoline DI passenger cars was mainly composed by BC and some organic droplets containing traces of other elements. During cold start GDI cars do emit important concentrations of BC and organic material. Emission of hydrocarbons has also been investigated. Gasoline DI emitted important concentration of THCs during cold start. Among the aliphatic compounds, families until C15 have been identified, confirming emission of heavier HCs from diesel cars. The second aim of this work was the study of atmospheric degradation of selected VOCs (toluene, naphthalene, cyclohexane, nonane) emitted from Euro 5 and Euro 6 vehicles and to determine the SOA formation potential of these compounds under different environmental conditions. The chosen compounds have been photoxidized (alone and in mixture) in an Aerosol Flow Tube (AFT) reactor in order to simulate VOCs atmospheric aging. The results suggest: (1) aromatic and PAHs compounds, own highest potential to form SOA; (2) the temperature has an important impact on SOA formation and yield; (3) the presence of pre-existing seed particles has, in general, a positive effect on SOA formation and (4) NOx has been found to negatively affect SOA formation; (5) SOA potential formation of VOC mixtures is highly influenced by the fraction of aromatics. Some of the products identified in the particle phase have never been previously reported. Degradation of aromatic compounds under medium NOx regime produced nitro-aromatic compounds identified both in the gas and particle phase. This PhD contributes to enrich vehicle emissions database, still limited for Euro 5 and Euro 6 cars. Speciation of non-regulated compound will help to better understand atmospheric SOA budget and car emissions air quality impacts. By last, the photoxidation study of primary VOCs (alone, mixture and full emissions) will lead to a better comprehension of SOA formation from vehicles
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Os engastes das sabedorias. A metafísica do real em Ibn\'Arabi / The mounting of wisdom. The metaphysics of reality in Ibn\'ArabiCastro, Ana Carolina Pinheiro e 14 November 2014 (has links)
A obra de Ibn Arab (1165 d.C. /560 H.) é bastante extensa, compreendendo cerca de 400 títulos, dos quais Kitb fu½½ al-¬ikam (O livro dos engastes das sabedorias) destaca-se como um dos principais escritos no qual o autor apresenta sua concepção metafísica, de forma mais sistematizada, como sua teoria dos nomes divinos através dos quais a essência do real procede, manifestando todos os existentes, assim como trata, de maneira aprofundada, do significado dos profetas e das sabedorias por eles transmitidas, propondo uma conotação totalmente metafísica para o profético. A profecia assume, nessa obra, uma importância fundamental, ela é apresentada como a condição de possibilidade da existência determinada, assim como também a condição de possibilidade do conhecimento da essência do real, ou seja, a condição de possibilidade de conhecer a realidade primeira. É interessante notar ainda a riqueza e a complexidade discursiva, na qual vida e obra encontram-se implicadas nesse processo de existenciação, de modo que tanto o autor quanto sua obra recebem estatutos muito significativos e particulares referentes ao sistema metafísico apresentado. Servindo-se da filosofia, da teologia e da mística arabo-islâmicas, oferecendo, com isso, um pensamento, embora complexo, de alcance universal que reconhece todos os profetas do ciclo histórico e as diversas tradições reveladas, a hermenêutica de Ibn Arab evidencia-se em muito original, promovendo um diálogo criativo e conciliador entre diversas culturas, permanecendo, até os dias de hoje, profundamente rico, inovador e inspirador para as mais diversas culturas e domínios do pensamento. / The work of Ibn \'Arab (1165 AD / H. 560) is quite extensive, comprising about 400 titles, of which Kitb fu½½ al-¬ikam (The Book of the bezels of wisdom) stands out as one of the major writings in which the author presents his metaphysical conception in a more systematic way as his theory of divine names, by which the essence of real conceives, showing all as he deeply addresses, the meaning of the prophets and the wisdom transmitted by them, proposing an entirely metaphysical connotation for the prophetic. On this work, the prophecy itself assumes a fundamental importance. It is presented as the condition of possibility of determined existence, as well as the condition of possibility of knowledge of the essence of real, i.e.: the condition of possibility of knowing the first reality. It is quite interesting to notice the richness and discursive complexity, in which life and the paper are implied in this existence process, so that both the author and his work receive very significant and specific status relating to the metaphysical system presented. Making use of philosophy, theology and the Arab-Islamic mysticism, offering thereby a thought, though complex, universal reach that recognizes all the prophets of the historical cycle and several revealed traditions, the hermeneutic of Ibn \'Arab evidences itself as being very original, promoting a creative and conciliatory dialogue among several cultures and remaining until this day, deeply rich, innovative and inspiring for several cultures and thought domains.
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Sistema microencapsulado contendo óleo essencial de citrus e processo de obtenção. / Microencapsulated system containing citrus essencial oil and obtaining process.BANDEIRA, Silmara Tavares. 01 June 2018 (has links)
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Previous issue date: 2017-06-01 / Os óleos essenciais são misturas naturais, complexas de substâncias voláteis que
possuem aroma intenso, são líquidos de aspecto oleoso a temperatura ambiente, mas se
volatilizam em exposição ao ar em temperaturas específicas. Considerados como os agentes antimicrobianos mais importantes presentes nas plantas, os óleos essenciais possuem também propriedades antioxidante, anti-inflamatória, inseticida, entre outras. O óleo essencial de laranja constitui-se de compostos aromatizantes quimicamente instáveis. Estes se degradam facilmente na presença de luz, ar e umidade. Pensando nisso, este trabalho estudou a microencapsulação do óleo essencial de laranja doce (Citrus sinensis v. dulcis) utilizando maltodextrina e gelatina como encapsulantes de baixo custo, como alternativa para aumento da estabilidade, além de incentivar a agregação de valor às cascas, rejeito do qual o óleo essencial é obtido, com vistas
à preservação ambiental. O estudo foi conduzido no Laboratório de Nutrição Animal, Centro de Saúde e Tecnologia Rural (CSTR), Universidade Federal de Campina Grande – UFCG, Campus de Patos – PB. Três formulações microencapsuladas foram desenvolvidas, em que os sistemas microencapsulados foram preparados com teor fixo de óleo essencial de laranja (10% m/m), variando-se a proporção de encapsulantes das formulações, em que a primeira incluiu apenas maltodextrina e as demais englobaram proporção de maltrodextrina e gelatina de 2:1 e 1:1, respectivamente. As formulações foram obtidas por emulsificação/liofilização. O estudo resultou em um pedido de patente (BR 10 2017 004722 9), depositado junto ao Instituto Nacional de Propriedade Industrial. O produto final obtido possui forte caráter de inovação tecnológica, além de maior segurança no manuseio, maior vida de prateleira e, portanto, o máximo de manutenção de integridade, somando-se, ainda, a possibilidade de inserção de um produto de alto valor agregado no mercado nacional, em que, dentre inúmeros setores, um dos
grandes favorecidos é a indústria alimentícia, incluindo, ainda, o fortalecimento da interação entre Universidade e Indústria e também a preservação do meio ambiente. / Essential oils are natural, complex mixtures of volatile substances that have intense aroma; they are liquids of oily appearance at room temperature, but they volatilize in
exposure to air at specific temperatures. Considered as the most important antimicrobial agents present in plants, essential oils also have antioxidant, anti-inflammatory, insecticidal properties, among others. Orange essential oil consists of chemically unstable flavoring compounds, which easily degrade in the presence of light, air and moisture. With this in mind, this work studied the microencapsulation of sweet orange essential oil (Citrus sinensis v. dulcis) using maltodextrin and gelatin as low cost encapsulants, as an alternative to increase stability, as well as to encourage the aggregation of value to the peels, from which the essential oil is obtained, aiming at environmental preservation. The study was conducted at the Animal Nutrition Laboratory, Center for Health and Rural Technology (CSTR), Federal University of Campina Grande - UFCG, Campus Patos - PB. Three microencapsulated formulations were developed in which the microencapsulated systems were prepared with fixed content of orange essential oil (10% m/m), varying the ratio of encapsulants of the formulations, in which the former included only maltodextrin and the others included proportion of maltodextrin and gelatin of 2: 1 and 1: 1, respectively. The formulations were obtained by emulsification / lyophilization. The study resulted in a patent application (BR 10 2017 004722 9), deposited with the National Institute of Industrial Property. The final product obtained has strong potential for technological
innovation, as well as greater handling safety, longer shelf life and, therefore, the maximum
integrity maintenance, also adding the possibility of insertion of a high - value product in the national market, where, among many sectors, one of the big beneficiaries is the food industry, including the strengthening of the interaction between University and Industry and also the preservation of the environment.
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O entardecer de uma era: t?cnica, poesia e pensamento em HeideggerLopes, Alan Marinho 15 April 2010 (has links)
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Previous issue date: 2010-04-15 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / The thinking dialog between Heidegger s philosophy and the poetry of H?lderlin and
Rilke must be dealt in language s domains. The difficulty to establish this dialog
comes from the man in itself, unable to think out of the understructure of science and
the modern technique. The poetic language was forgotten or ignored, turning itself
obsolete in front of improvements and resources of the technique. Heidegger
searches the essences to the poetry so may it be comprehended in its plenitude for
the man. Technique, poetry and existence must be pronounced and investigated so
the being shows itself again. To Heidegger, the man lives in a period of uncertainty
due finding himself at the sunset of age. The uncertainty generates the poverty and
the night of world represents the absence of god and original truth. Only with the
fundamental comprehension of poetry, the man of today can project himself to the
future not anymore as technique product, but with freedom to choose. The message
of poetry of H?lderlin and Rilke, according to Heidegger s interpretation, transmits an
alert to the contemporary man against the coming danger in his maintained relation
with nature. The purpose of the following work is to build this thinking dialog, without
disfigure the poetry, but taking approach over its essence, so from there to remove
its true existential value. / O di?logo pensante entre a filosofia de Heidegger e a poesia de H?lderlin e Rilke
deve ser travado nos dom?nios da linguagem. A dificuldade em estabelecer esse
di?logo vem do pr?prio homem, incapaz de pensar fora do arcabou?o da ci?ncia e
da t?cnica moderna. A linguagem po?tica foi esquecida ou ignorada, tornando-se
obsoleta diante das facilidades e recursos da t?cnica. Heidegger busca as ess?ncias
para que a poesia possa ser compreendida em sua plenitude pelo homem. T?cnica,
poesia e exist?ncia devem ser pronunciadas e investigadas para que o ser se
apresente novamente. Para Heidegger, o homem vive em um per?odo de incertezas
por se encontrar no entardecer de uma era (Sunset of Age). A incerteza gera a
pen?ria e a noite do mundo representa a aus?ncia de Deus e das verdades
origin?rias. Apenas com a compreens?o fundamental da poesia, o homem de hoje
pode se projetar ao futuro n?o mais como produto da t?cnica, mas com liberdade
para escolher. A mensagem da poesia de H?lderlin e Rilke, segundo a interpreta??o
de Heidegger, transmite um alerta ao homem contempor?neo acerca do perigo
vigente na rela??o que ele mant?m com a natureza. O objetivo do seguinte trabalho
? construir esse di?logo pensante, sem desfigurar a poesia, mas indo de encontro ?
sua ess?ncia, para de l? retirar seu verdadeiro valor existencial.
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Os engastes das sabedorias. A metafísica do real em Ibn\'Arabi / The mounting of wisdom. The metaphysics of reality in Ibn\'ArabiAna Carolina Pinheiro e Castro 14 November 2014 (has links)
A obra de Ibn Arab (1165 d.C. /560 H.) é bastante extensa, compreendendo cerca de 400 títulos, dos quais Kitb fu½½ al-¬ikam (O livro dos engastes das sabedorias) destaca-se como um dos principais escritos no qual o autor apresenta sua concepção metafísica, de forma mais sistematizada, como sua teoria dos nomes divinos através dos quais a essência do real procede, manifestando todos os existentes, assim como trata, de maneira aprofundada, do significado dos profetas e das sabedorias por eles transmitidas, propondo uma conotação totalmente metafísica para o profético. A profecia assume, nessa obra, uma importância fundamental, ela é apresentada como a condição de possibilidade da existência determinada, assim como também a condição de possibilidade do conhecimento da essência do real, ou seja, a condição de possibilidade de conhecer a realidade primeira. É interessante notar ainda a riqueza e a complexidade discursiva, na qual vida e obra encontram-se implicadas nesse processo de existenciação, de modo que tanto o autor quanto sua obra recebem estatutos muito significativos e particulares referentes ao sistema metafísico apresentado. Servindo-se da filosofia, da teologia e da mística arabo-islâmicas, oferecendo, com isso, um pensamento, embora complexo, de alcance universal que reconhece todos os profetas do ciclo histórico e as diversas tradições reveladas, a hermenêutica de Ibn Arab evidencia-se em muito original, promovendo um diálogo criativo e conciliador entre diversas culturas, permanecendo, até os dias de hoje, profundamente rico, inovador e inspirador para as mais diversas culturas e domínios do pensamento. / The work of Ibn \'Arab (1165 AD / H. 560) is quite extensive, comprising about 400 titles, of which Kitb fu½½ al-¬ikam (The Book of the bezels of wisdom) stands out as one of the major writings in which the author presents his metaphysical conception in a more systematic way as his theory of divine names, by which the essence of real conceives, showing all as he deeply addresses, the meaning of the prophets and the wisdom transmitted by them, proposing an entirely metaphysical connotation for the prophetic. On this work, the prophecy itself assumes a fundamental importance. It is presented as the condition of possibility of determined existence, as well as the condition of possibility of knowledge of the essence of real, i.e.: the condition of possibility of knowing the first reality. It is quite interesting to notice the richness and discursive complexity, in which life and the paper are implied in this existence process, so that both the author and his work receive very significant and specific status relating to the metaphysical system presented. Making use of philosophy, theology and the Arab-Islamic mysticism, offering thereby a thought, though complex, universal reach that recognizes all the prophets of the historical cycle and several revealed traditions, the hermeneutic of Ibn \'Arab evidences itself as being very original, promoting a creative and conciliatory dialogue among several cultures and remaining until this day, deeply rich, innovative and inspiring for several cultures and thought domains.
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Catalyseurs électrochimiques pour le stockage et la réduction des oxydes d'azote (NOx) / Electrochemical catalysts for nitrogen oxides storage/reductionHadjar, Abdelkader 22 July 2009 (has links)
L’objectif de ce travail était de démontrer la possibilité de coupler sur un même catalyseur, la fonction de stockage et réduction des NOx (sur le baryum) avec un effet électrochimique reposant sur un système micropile. Ce système micropile est composé de nanoparticules catalytiques (Pt et Rh) déposés sur conducteur ionique par les ions O2- (YSZ) en contact avec un support conducteur électronique (SiC dopé) de façon à pouvoir générer, sous mélanges réactionnels, une force électromotrice capable de réduire électrochimiquement une partie des NOx sur le Pt et d’oxyder le CO, les hydrocarbures imbrûlés et H2 sur le Rh. L’effet micropile a été observé sur un catalyseur Pt/Ba (matériau de stockage)/YSZ/Rh enduit dans les canaux d’un filtre à particule en carbure de silicium dopé, en condition essence pauvre à 400°C et en condition Diesel à plus basse température (300°C). Une augmentation de la conversion des NOx d’environ 10% a été observé sur les catalyseurs micropile. L’effet électrochimique a été détecté par une surproduction de CO2, en milieu riche (très peu ou pas de O2) provenant de la réaction d’oxydation électrochimique du CO (produit par vaporeformage) en réagissant avec les ions O2- provenant de YSZ. De plus, des tests catalytiques ont montré que YSZ peut être utilisée comme matériau de stockage des NOx. En effet, un traitement réducteur préalable augmente fortement sa capacité de stockage des NOx / The main objective of this study was to demonstrate the coupling between NOx storage/reduction process on barium, with an electrochemical reduction of NOx (micro fuel cell effect) on the same catalyst. The micro fuel cell effect is ensured by a an electromotive force (potential) which is created between catalytic nanoparticules (Pt and Rh) in contact with an ionic conductor (YSZ) and an electronic conductor (doped SiC). The micro fuel cell effect was observed, during the regeneration phase of the catalysts (rich period), on a Pt/Ba/doped α-SiC-YSZ/Rh monolithic system under lean-burn gasoline conditions at 400°C with an enhancement of about 10 % of the NOx conversion over a complete cycle lean/rich. This electrochemical effect was characterized by the electrochemical oxidation of CO (produced by steam reforming) into CO2 by using O2- ions coming from YSZ. Under Diesel conditions, the micro fuel cell system was found to work at low temperature especially at 300°C. In the second part of the work, a new generation of NOx Storage and reduction catalyst was developed consisting only of noble metals (Pt and/or Rh) deposited on YSZ support (Ba free catalyst). The catalytic measurements revealed that YSZ can be used as a NOx storage material in lean burn conditions (Gasoline and Diesel) especially when it was previously reduced under hydrogen. The storage mechanism would take place on the oxygen vacancies created by the removal of O-2 ions from the YSZ structure
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Etude par PIV par fluorescence de l’interaction d’un spray avec un écoulement gazeux en aérodynamique contrôlée : application à l’injection directe essence / Study by means of PIV by fluorescence of the interaction between a spray and a gaseous flow in a controlled aerodynamic : application to the gasoline direct injectionLemetayer, Julien 07 December 2016 (has links)
De nombreux procédés actuels mettent en jeu des écoulements diphasiques (sprays agricoles, pharmaceutiques, peinture...). Néanmoins, la connaissance des mécanismes régissant les interactions entre les phases (entraînement, modification des trajectoires des particules, transfert d'énergie...) est encore incomplète, notamment lors de l'injection directe essence, qui représente le cadre de cette étude. Dans cette étude expérimentale, les dynamiques instantanées des deux phases sont étudiées dans un plan pour mettre en évidence les interactions aérodynamiques entre les phases. Pour ce faire, un diagnostic de FPIV diphasique, utilisant un colorant fluorescent pour chaque phase, est développé afin d'acquérir simultanément des images séparées de chaque phase sur deux caméras indépendantes. Ainsi, les vitesses instantanées et simultanées des deux phases sont mesurées sans recourir à un prétraitement des images. Dans un premier temps, ce diagnostic optique est appliqué à la caractérisation d'une injection dans un gaz au repos. L'injection du spray met en mouvement le gaz par le biais d'un transfert de quantité de mouvement du spray vers le gaz. La dispersion des gouttes du spray et le mélange des deux phases qui résultent de ces transferts d'énergie cinétique dépendent du type de spray et également de la pression d'injection. Dans un second temps, ces interactions sont étudiées dans un moteur monocylindre transparent. La comparaison entre les fonctionnements avec et sans injection indique un impact notable de la présence du spray sur l'aérodynamique interne par le développement de nouvelles structures et la modification des caractéristiques du tumble. L'aérodynamique interne du moteur modifie également le développement du spray en comparaison de l'injection dans un gaz au repos. / Two-phase flows are involved in numerous actual industrial processes (agriculture, pharmacy, painting...). However, the complex interactions between phases (entrainment, particle trajectory modification, energy transfer...) are not well understood, especially for the gasoline direct injection, which represents the context of this study. For this experimental study, instantaneous dynamics of both phases are studied in a plan to highlight the aerodynamic interactions between phases. To achieve that, a two-phase FPIV diagnostic, based on using a fluorescent dye for each phase, is developed to simultaneously acquire separated images of each phase on two independent cameras. Instantaneous and simultaneous velocities of both phases are measured without any image pre-processing. Firstly, this optical diagnostic is applied to the characterisation of a spray injection in a gas at rest. The spray drags the gas by a momentum transfer from spray to gas. The spray droplet dispersion and the mixture between the two phases, which result from this kinetic energy transfer, depend on the spray topology and the injection pressure. Then, these interactions are studied in a transparent monocylinder engine. The comparison between cycles with and without injection reveals a significant impact of the spray presence on the internal aerodynamic through the development of new structures and the modification of tumble characteristics. The internal aerodynamic also modifies the spray development in comparison to the injection in a gas at rest.
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Isolation of Pelargonium alchemilliodes L L'Her active compounds and their effects on bacterial growth and keratinocytes in vitroMakanyane, Madikoloho Daniel 07 1900 (has links)
M. Tech. (Department of Chemistry and Biotechnology, Faculty of Applied and Computer Sciences), Vaal University of Technology. / Context: Pelargonium alchemilliodes L L' Her is an evergreen shrub, cultivated principally for the medicinal essence and decoction in Southern Africa for the treatment of skin problems, and wounds. Objective: the aim of the study was to optimize the extraction of phenolics and flavonoids from P. graveolens by response surface methodology with particular attention on the proliferative and cytotoxic effects on human keratinocytes, as well as the antioxidant and antibacterial activities and also to isolate active compounds. Materials and Methods: The optimization was achieved by Box-Behnken design. Extract, metabolite yields, and minimal inhibitory concentrations (MIC) were determined by gravimetric, spectrophotometric, and microdilution methods, respectively. The antiradical potentials were evaluated using the phosphomolybdate. 2,2-diphenyl-1-picrylhydrazyl, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), and lipid peroxidation assays, the diterpenoids were isolated and purified using open column chromatography, PTLC, and characterized with FTIR, NMR. The kinetics of the lipid protective activity was studied and fitted into models. The proliferative and cytotoxic effects were evaluated using the CellTiter® Blue cell viability and lactate dehydrogenase assay. Results: The regression coefficient r2 ≥ 0.9775 indicated a close correlation between actual and predicted values of the responses. The ideal parameter for the extraction of phenolics and flavonoids by macerations was determined as an extraction time: 9.63-12.01 h, material mass: 2.62-3.00 g, agitation speed: 143.11-197.11 rpm, and solvent volume: 68.06-69.87 mL. The optimal extractable acetone and methanol crude, flavonoids, and phenolic are (28.87±2.15%, 24.11±1.15%), (7.11±1.03 mg QE/g, 5.98±0.87 mg QE/g) and (58.08±0.88 mg GAE/g, 55.91±1.15 mg GAE/g), respectively. The detected different chemical groups of polyphenolic compounds such as alkaloids, saponins , sterols, terpenoids, flavonoids, tannins, phenols and cardiac glycosides from methanol and acetone extracts were in correlation with optimized yields. Two triterpenoids compounds 1-hydroxy-30-norlanosta-6, 8-diene and 1 2,3,4a,8,9,10,10a-octahydro-2-(2-hydroxypent-4-enyl)-4a-vinyl-1H-benzo[c]chromen-6(10bH)-one were isolated form methanol extracts. The main components of essential oils were citronellal (5.99%), citranellol (26.2%), geraniol (8.56%), citronellyl butyrate (20.3%), trans-farnesol (9.53%) and they were characterized by high amounts of oxygenated hydrocarbons (67.6%), followed by sesquterpene hydrocarbons and oxygenated sesquiterpene (9.32%) and the least being mornoterpene hydrocarbons (5.20%). Total antioxidant capacity and reducing power were comparable to standard gallic acid, while the antiradical activity has IC50 value of 0.18±0.03-8.98±0.15 mg/mL. Further, the lipid protective revealed a dose-dependent activity fitting into a pseudo-second-order kinetic model. MIC value of 1.56 mg/mL for extracts was registered against Staphylococcus aureus and salmonella typhi comparable to chloramphenicol. There was a significant (P < 0.05) increase in cell proliferation and viability when the extract was administered at concentrations of ≤50 μg/mL. However, at ≥100 μg/mL concentrations at ≤ 1000 μg/mL for essential oil exhibited a significnt cytotoxicity in comparison to the untreated cell. Conclusion: These biological activities are confirmation of the phytomedicinal application and possible source of pharmaceutical compounds. However, administration of the decoction should take into cognizance the antiproliferative effect at doses ≥100 μg/mL as well as the potential to induce and maintain keratinocyte proliferation at low concentration with an eye on the antiproliferative effect at concentrations ≥100 μg/mL, except the P. Alchemilliodes essential oils at ≤ 1000 μg/mL.
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