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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.
1

Detection of Pre-ignition Events using Deep Neural Networks

Kuzhagaliyeva, Nursulu 08 1900 (has links)
Abstract: Engine downsizing and boosting have been some of the most widely used strategies for improving engine efficiency in recent years. Several studies have offered significant departures from on-road pre-ignition to steady-state engine laboratory studies, necessitating more robust data-driven diagnostic tools that can identify pre-ignition events in real world environments. The goal of this study is to apply deep neural networks for pre-ignition (PI) detection, based on scientific data obtained from less expensive sensors (like lambda and low-resolution exhaust back pressure (EBP) data), as a replacement for high resolution in-cylinder pressure measurements. Two deep neural network (DNN) models are proposed and applied for classification of 221,728 combustion cycles from 18 experiments with varying EBP. DNNs combined convolutional neural networks (CNNs) for detection of repetitive patterns in array-structured data, and recurrent neural networks (RNNs) for modelling in a temporal domain. The first model was fed data from the principal component analysis (PCA); the second model eliminated this step and was focused on time series input. As a performance metric, the area under the curve (AUC) of the receiving operating curve (ROC) was used for comparison of the two models. The model’s accuracy was tested on 44,305 cycles. Based on the AUC-ROC metric, the former model was better able to differentiate between pre-ignition and normal combustion cycles.
2

Analyse thermique avancée pour l’étude et la caractérisation de produits pétroliers complexes tels que les bitumes / Advanced thermal analysis for the sudy and characterization of complex petroleum products

Moncel, Matthieu 19 December 2014 (has links)
Au cours de cette thèse, de nouvelles méthodes d’analyse thermique et de traitement des données applicables à l’étude et la caractérisation de produits pétroliers complexes, ont été proposées, afin de mieux caractériser les bitumes. Le bitume, sous-produit de l’industrie pétrolière, est un matériau complexe dont les propriétés et la composition changent au gré des cocktails de pétroles bruts ou des procédés de raffinage. Une connaissance approfondie des propriétés de chaque bitume est donc nécessaire. Les tests mécaniques normés utilisés aujourd’hui pour caractériser le bitume sont insuffisants. Afin de pallier ce problème les techniques de DSC avancées ont été exploitées. Ce travail a porté principalement sur l’étude des trois phénomènes pouvant être observés au cours du chauffage des bitumes: la transition vitreuse, la cristallisation et la fusion. La première partie de ce travail a été consacrée à l’étude de ces trois phénomènes sur des molécules modèles, la diéthanolamine et la triéthanolamine. L’intérêt de la perturbation stochastique de température (TOPEM®) réside notamment dans la possibilité de séparer certains phénomènes se produisant sur un même domaine de températures. La méthodologie développée a ensuite été appliquée aux bitumes afin de mettre en évidence des corrélations entre données DSC (fraction cristallisable, température de transition vitreuse, température et enthalpie de fusion) et données mécaniques. Il a été montré également que la calorimétrie ultra-rapide permet de séparer certains phénomènes grâce à une approche différente mais complémentaire à la perturbation stochastique de température TOPEM®. / This thesis tackled new methods of thermal analysis and data treatment applicable to the study and characterization of complex petroleum products. The objective was to better characterize bitumen, which, as a by-product of petroleum industry, is a complex material. Its properties and composition are not set and change according to the cocktails of crude oils or to the refining processes. Thorough knowledge of the properties of asphalt is thus necessary to be able to use them in the best conditions. The standardized mechanical tests used today to characterize the asphalt are insufficient. To compensate for this problem, the techniques of advanced DSC were exploited. This work concerned mainly the study of three phenomena which can be observed during the heating of asphalts: glass transition, crystallization, and melting. The first part of this work was dedicated to the study of these three phenomena on model molecules _ the diethanolamine and the triethanolamine _ as they were presenting thermal events in a range of temperatures similar to the one of bitumen. The interest of the stochastic temperature perturbation (TOPEM®) lies in particular in the possibility of separating some phenomena occurring on the same range of temperatures. Thus, thanks to this method, glass transition can be analyzed independently of the enthalpic relaxation or of the crystallization. The developed methodology was then applied to bitumen so as to highlight correlations between DSC data and mechanical data . It was also shown that the ultra-fast calorimetry enables to separate some phenomena thanks to a different but complementary approach of stochastic temperature perturbation TOPEM®.
3

Biodegradation of Methyl Tert-Butyl Ether and Tert-Butyl Alcohol Using Bioaugmentation with BiOWiSH® Aqua

Villanueva, Elizabeth 01 December 2022 (has links) (PDF)
Aqua, a commercial product manufactured by BiOWiSH® Technologies, was utilized in this research to study its effectiveness to biodegrade methyl tert-butyl ether (MTBE) and tert-butyl alcohol (TBA). Microcosms containing varying concentrations of MTBE and TBA as well as a growth media and mineral salt solution were examined. Analytical instrumentation used in this study included the use of a gas chromatograph-mass spectrometer (GC/MS) to determine concentrations of MTBE and TBA and a spectrophotometer to extrapolate approximate active biomass concentrations in each experiment. Four different environmental conditions were tested for both MTBE and TBA. The environmental conditions tested for each contaminant included: biodegradation under aerobic conditions, biodegradation under anaerobic conditions, biodegradation under denitrifying conditions, and biodegradation under aerobic conditions with glucose present. This study concluded that there is potential for degradation of MTBE and TBA using Aqua under the conditions tested. Maximum MTBE biodegradation was observed under aerobic conditions which yielded a first order rate constant of 0.019/hour and a 99.8 percent decrease in MTBE over 14 days. Maximum TBA biodegradation was observed under aerobic conditions with glucose present which yielded a first rate order constant of 0.009/hour and a 95.03 percent decrease in TBA concentrations over 14 days. It is presumed that under both conditions a monooxygenase enzymatic reaction involving Cytochrome P-450 aids in breaking down both MTBE and TBA. However, the results presented are indicative of biodegradation under lab conditions with little to no interference. Further research is needed to determine the effectiveness of Aqua utilizing groundwater or soil samples from MTBE or TBA contaminated sites in order to truly analyze Aqua’s potential to be used as a bioaugmentation product in real world applications.
4

Adsorption Removal of Tertiary Butyl Alcohol from Wastewater by Zeolite

Butland, Tricia Dorothy 29 April 2008 (has links)
Tertiary butyl alcohol (TBA) is used as a fuel oxygenate and is the main breakdown component of methyl tert butyl ether (MTBE). As such, TBA is found in water systems through storage leaks and spills, presence of MTBE in the water, and as an impure byproduct of MTBE-blended fuels. It presents several health hazards and is a suspected carcinogen. Studies involving aquatic life, mice and rats indicate that TBA is a concern at low concentrations. Wastewater removal of tert butyl alcohol (TBA) has been limited to methodology used by MTBE or by anaerobic or aerobic methods. Neither set of techniques is applicable to TBA due to its long biological degradation period, its very specific conditions for anerobic or aerobic treatment, and its low Henry's law constant, low transformation rate, and its high mobility. The main goal of this project was to determine the adsorption capabilities of different zeolites for TBA. A comparison to previous work done with powdered zeolites and MTBE is shown in the following Chapters. Batch systems of TBA and several different zeolites were examined to determine the best zeolites for TBA adsorption. As shown in Chapter 3, the best zeolites for TBA adsorption over an equilibrium time of 48 hours were silicalite and HiSiv 3000 pellets. Using the two chosen zeolites, silicalite and HiSiv 3000, adsorption isotherms were created and compared against MTBE data using the same data. The final portion of this project included a continuous system consisting of a zeolite column and a steady flow rate of TBA. The zeolite columns consisted of sole silicalite, sole HiSiv 3000, and different proportions of the two zeolites in the same column. All column experiments were run at similar conditions with variation in the adsorbent bed lengths for easy comparison between the resulting breakthrough curves. At the 3-cm bed length, the zeolite columns outperformed the activated carbon column; however, there was no distinct difference between the zeolite columns. In the 6-cm bed length experiments, there were apparent differences between the two zeolite breakthrough curves. The 9-cm column did not differentiate between the zeolites.
5

Tillämpad Beteendeanalys - eller varför slåss Kalle?

Dahlgren, Maria January 2006 (has links)
Syftet med uppsatsen var att beskriva och bedöma om TBA var en bra metod för att arbeta med beteendeproblem hos barn inom barnomsorg och skola.Studien gav kunskap om beteendeterapi och behavioristerna genom historik, fakta om tillämpad beteendeanalys samt TBA, som var den metod jag använde mig av. Studien byggde på deltagande observationer. Tre utvalda elever med olika beteendeproblem observerades och analyserades enligt TBA.Sammanfattningsvis pekade resultatet av studien på att TBA var en väl fungerande analysmetod för fastställande av beteendeproblemets typ och art. Som arbetsmetod för beteendeproblem var TBA väl fungerande vid enklare beteendeproblem, men behövde komplitteras vid svårare beteendeproblem med flera bakomliggande faktorer. / The purpose with the essay was to describe and judge if ABA was as good method for working with behaviourproblems in children within childcare and school.The study gave knowledge about behaviourtheraphy and the behaviourists through history, facts about ABA, that was the method I used. The study was based on participational observations. Three choosen pupils with diffrent behaviourproblems was observed and analysed according to ABA.To sum up the result of the study pointed at ABA to be a well-functioned analysing method to determine the typ and sort of the behaviorproblem. As a workingmethod for behaviourproblems ABA was well-funvtioned in simpler behaviorproblems, but needs to be completed in more difficult behaviorproblems with more underlying factors.
6

The contribution of N-terminally modified amyloid beta to the etiology of Alzheimer's disease

Wittnam, Jessica L. 21 May 2012 (has links)
No description available.
7

Contribution à l'utilisation des polymères à mémoire de forme pour les structures à amortissement contrôlé / Contribution to using shape memory polymers for the control of structural damping

Butaud, Pauline 01 December 2015 (has links)
Ces travaux de thèse proposent utiliser les polymères à mémoire de forme comme moyen de contrôle desvibrations des structures. Outre hystérésis de mémoire qui est classiquement mis en avant, ces matériauxpossèdent des propriétés amortissantes intrinsèques qui sont d'autant plus intéressantes lorsque l’effetmémoire de forme est important. Dans un premier temps une caractérisation des propriétés mécaniques dutBA/PEGDMA, polymère à mémoire de forme de l'étude, est effectuée par analyse dynamique mécanique.Un modèle rhéologique basé sur lʹéquivalence temps-température, le 2S2P1D, est utilisé pour rendre comptedu comportement viscoélastique du polymère. Dans un deuxième temps, une campagne expérimentale estmenée, sur une large bande de fréquences et de températures, grâce à divers moyens expérimentaux(statiques, modaux, nano-indentations, ultrasons, dynamiques hautes fréquences, microscopie acoustique)afin de définir le domaine de validité, fréquentiel et thermique, du modèle rhéologique. Dans un troisièmetemps, le polymère à mémoire de forme est intégré à une structure composite de type sandwich pour mettreen évidence le pouvoir amortissant impressionnant du matériau. Enfin, une méthodologie de contrôle delʹamortissement par la température est proposée. En effet, la dissipation d’énergie dans le sandwich sʹavèrecontrôlable, la température permettant d’ajuster la rigidité et le facteur de perte du tBA/PEGDMA pour unamortissement optimal sur une large bande de fréquences. / This work proposes to use shape memory polymers to control structural vibrations. These materials exhibit amemory hysteresis which is practically associated with intrinsic damping properties which are very highwhen the memory effect is strong. First, a thermomechanical characterization of the shape memory polymerof interest (tBA/PEGDMA) is performed by dynamic mechanical analysis. A rheological model based on timetemperaturesuperposition is used to represent the viscoelastic behavior of the polymer. Secondly, anexperimental campaign is performed over a wide frequency and temperature range, through variousexperimental techniques (static, modal, nanoindentation, ultrasounds, high frequency dynamic analysis,acoustic microscopy) to define the area of validity, in frequency and temperature, of the rheological model.Third, the shape memory polymer is integrated into a composite sandwich structure to highlight the awesomedamping capabilities of the material. Finally, a damping tuning methodology by temperature control isproposed. Indeed, the power dissipation in the sandwich is related to physical properties of the tBA/PEGDMA core which are temperature-controlled to optimize the damping over a given frequency range.
8

DEVELOPMENT AND APPLICATION OF EFFECTIVE FRAGMENT POTENTIALS FOR (BIO)MOLECULAR SYSTEMS

Yongbin Kim (9187811) 31 July 2020 (has links)
<div> <div> <div> <p>The Effective Fragment Potential (EFP) is a quantum-mechanical based model potential for accurate calculations of non-covalent interactions between molecules. It can be coupled with ab initio methods in so-called QM/EFP models to explore the electronic properties of extended molecular systems by providing rigorous description of surrounding environments. The current EFP formulation is, however, not well suited for large-scale simulations due to its inherent limitation of representing effective fragments as rigid structures. The process of utilizing EFP method for the molecular systems with flexible degrees of freedom entails multiple sets of parameter calculations requiring intensive computational resources. This work presents development of the EFP method for describing flexible molecular systems, so-called Flexible EFP. To validate the applicability of the Flexible EFP method, extensive benchmark studies on the amino acid interactions, binding energies, and electronic properties of flavin chromophore of the cryptochrome protein have been demonstrated. In addition to methodological developments, excitonic properties of the Fenna-Matthews-Olson (FMO) photosynthetic pigment-protein complex are explored. In biological systems where intermolecular interactions span a broad range from non-polar to polar and ionic forces, EFP is superior to the classical force fields. In the present study, we demonstrate excellent performance of the QM/EFP model for predicting excitonic interactions and spectral characteristics of the FMO wildtype complex. We characterize the key factors for accurate modeling of electronic properties of bacteriochlrophyll a (BChl a) photosynthetic pigments and suggest a robust computational protocol that can be applied for modeling other photosynthetic systems. Developed computational procedures were also successfully utilized to elucidate photostability and triplet dynamics in the FMO complex and spectroscopic effects of single-point mutagenesis in FMO. A combination of polarizable EFP molecular dynamics and QM/EFP vibrational frequency calculations were also applied to understanding and interpreting structures and Raman spectroscopy of tert-butyl alcohol solutions. </p> </div> </div> </div>
9

Processos de transfronteirização na Bacia do Prata : a tríplice fronteira Brasil – Argentina - Paraguai

Carneiro Filho, Camilo Pereira January 2013 (has links)
Cette recherche est une approche sur les processus transfrontaliers dans la Triple FrontièreBrésil-Argentine-Paraguay. Initialement nous avons cherché à identifier les acteurs et les nouveaux usages du territoire, ainsi que le rôle des régions transfrontalières au sein des blocs commerciaux régionaux en Amérique du Sud et en Europe. Afin de utiliser l'expérience européenne dans les politiques pour les régions frontalières, on a analysés les initiatives d'intégration dans l’Union européenne et un travail de terrain dans la Grande Région a été réalisé, dont les résultats ont été utilisés pour la composition d'un chapitre de la recherche. Au cours du present étude l'importance de l'infrastructure routière, l'énergie et les télécommunications, le rôle du tourisme, les diverses initiatives de coopération et d'interaction dans le Triple Frontière, ainsi que les effets négatifs desprocessus transfrontaliersont été également analysé. Dans la recherche, les acteurs et les processus transfrontaliers ont été signalées par des coremas et des cartes. Les éléments énumérés ont servi à soutenir l'idée que actuellement une régiontransfrontalière se dessine au coeur du bassin de La Plata. / A presente pesquisa constitui uma abordagem acerca dos processos de transfronteirização na Tríplice Fronteira Brasil-Argentina-Paraguai. Inicialmente buscou-se identificar os atores e os novos usos do território, bem como o papel das regiões transfronteiriças dentro dos blocos regionais de comércio na América do Sul e na Europa. Com o intuito de aproveitar a experiência europeia no âmbito das políticas para regiões transfronteiriças, foram analisadas as iniciativas de integração e foi realizado um trabalho de campo na Grande Région, cujos resultados serviram para a composição de um capítulo da pesquisa. No decorrer da pesquisa também foram analisados a importância das infraestruturas viárias, energéticas e de telecomunicações, o papel do turismo, as diferentes iniciativas de cooperação e interação na Tríplice Fronteira, bem como os efeitos negativos da transfronteirização. Os atores e os processos de transfronteirização foram relatados através de coremas e mapas elaborados para a pesquisa. Os elementos elencados serviram para embasar a ideia de que está surgindo uma região transfronteiriça no coração da Bacia do Prata. / This research is an approach to cross-border processes in the Tri-Border Area, between Brazil, Argentina and Paraguay. Initially we sought to identify the actors, the new land uses and the role of cross-border regions within regional trading blocs in South America and Europe. To take advantage of the European experience in policies for border regions, we analyzed the integration initiatives in the European Union and a fieldwork in the Grande Région was conducted. The results of the fieldwork were used to compose a chapter of the research. In the present study the importance of road infrastructure, energy and telecommunications, the role of tourism, initiatives of cooperation and interaction in Tri-Border Area, as well as the negative effects of cross-border processes were also analyzed. In the present research, actors and border processes have been reported by graphic schemes and maps. The items listed were used to support the idea that, presently, a cross-border region is emerging in the heart of La Plata Basin.
10

Processos de transfronteirização na Bacia do Prata : a tríplice fronteira Brasil – Argentina - Paraguai

Carneiro Filho, Camilo Pereira January 2013 (has links)
Cette recherche est une approche sur les processus transfrontaliers dans la Triple FrontièreBrésil-Argentine-Paraguay. Initialement nous avons cherché à identifier les acteurs et les nouveaux usages du territoire, ainsi que le rôle des régions transfrontalières au sein des blocs commerciaux régionaux en Amérique du Sud et en Europe. Afin de utiliser l'expérience européenne dans les politiques pour les régions frontalières, on a analysés les initiatives d'intégration dans l’Union européenne et un travail de terrain dans la Grande Région a été réalisé, dont les résultats ont été utilisés pour la composition d'un chapitre de la recherche. Au cours du present étude l'importance de l'infrastructure routière, l'énergie et les télécommunications, le rôle du tourisme, les diverses initiatives de coopération et d'interaction dans le Triple Frontière, ainsi que les effets négatifs desprocessus transfrontaliersont été également analysé. Dans la recherche, les acteurs et les processus transfrontaliers ont été signalées par des coremas et des cartes. Les éléments énumérés ont servi à soutenir l'idée que actuellement une régiontransfrontalière se dessine au coeur du bassin de La Plata. / A presente pesquisa constitui uma abordagem acerca dos processos de transfronteirização na Tríplice Fronteira Brasil-Argentina-Paraguai. Inicialmente buscou-se identificar os atores e os novos usos do território, bem como o papel das regiões transfronteiriças dentro dos blocos regionais de comércio na América do Sul e na Europa. Com o intuito de aproveitar a experiência europeia no âmbito das políticas para regiões transfronteiriças, foram analisadas as iniciativas de integração e foi realizado um trabalho de campo na Grande Région, cujos resultados serviram para a composição de um capítulo da pesquisa. No decorrer da pesquisa também foram analisados a importância das infraestruturas viárias, energéticas e de telecomunicações, o papel do turismo, as diferentes iniciativas de cooperação e interação na Tríplice Fronteira, bem como os efeitos negativos da transfronteirização. Os atores e os processos de transfronteirização foram relatados através de coremas e mapas elaborados para a pesquisa. Os elementos elencados serviram para embasar a ideia de que está surgindo uma região transfronteiriça no coração da Bacia do Prata. / This research is an approach to cross-border processes in the Tri-Border Area, between Brazil, Argentina and Paraguay. Initially we sought to identify the actors, the new land uses and the role of cross-border regions within regional trading blocs in South America and Europe. To take advantage of the European experience in policies for border regions, we analyzed the integration initiatives in the European Union and a fieldwork in the Grande Région was conducted. The results of the fieldwork were used to compose a chapter of the research. In the present study the importance of road infrastructure, energy and telecommunications, the role of tourism, initiatives of cooperation and interaction in Tri-Border Area, as well as the negative effects of cross-border processes were also analyzed. In the present research, actors and border processes have been reported by graphic schemes and maps. The items listed were used to support the idea that, presently, a cross-border region is emerging in the heart of La Plata Basin.

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