Cette étude concerne la physique des écoulements convectifs résultant d’une instabilité d’évaporation de fluides binaires. Ce problème a de nombreuses applications, l’enrobage par centrifugation, le dépôt de films, les caloducs, etc, pour lesquels le changement de phase et la convection jouent un rôle prépondérant dans la conception et la qualité des procédés. Le système physique étudié est un mélange liquide sous sa propre vapeur, confiné par deux plaques conductrices de chaleur et des bords latéraux isolants. Les plaques sont utilisées pour appliquer un gradient thermique. Aucun gradient de concentration n’est imposé au système. Ces gradients sont induits par les différentes vitesses d’évaporation des composés. Dans ce système, il est important de comprendre comment la dynamique des fluides et les transferts de masse et de chaleur entrent en compétition pour la formation de structures. Le principal objectif de ce travail est d’identifier les conditions pour que le système évolue d’un état conductif vers un état de convection lorsque le gradient vertical de température dépasse une certaine valeur critique.Dans le système, la convection s’installe par trois mécanismes distincts : évaporation, gradients de densité et gradients de tension interfaciale. Trois forces convectives s’opposent aux effets de diffusion qui tendent à garder le système en état conductif. Le seuil d’apparition de la convection dépend de quelques variables, comme les dimensions du contenant, les propriétés thermophysiques des phases liquide et vapeur, la fraction massique, et les caractéristiques de perturbations. L’effet de chacune de ces variables sur le seuil est étudié en présence ou non de gravité.Pour représenter la physique, un modèle mathématique non linéaire complet est développé, basé sur les conservations de quantité de mouvement, d’énergie et de masse dans chaque phase avec les conditions aux limites appropriées. Le fluide binaire est composé de deux alcools légers comme l’éthanol et le sec-butanol. Dans les équations du modèle, la masse volumique ainsi que la tension interfaciale sont fonctions à le fois de la température et de la concentration. Pour la recherche du seuil de transition, les équations sont linéarisées autour d’un état de base connu. Dans notre cas, il s’agit de l’état conductif. Le système d’équations linéaires résultant est résolu par une méthode de collocation spectrale Chebyshev.Nous obtenons quatre résultats principaux. Premièrement, dans un système multi-composants sans gravitation, une instabilité n’apparaît que lorsque le système est chauffé du côté de la phase vapeur contrairement à un système mono-composant. Cela implique que, si on souhaite éviter les instabilités, il vaut mieux un apport de chaleur par la phase liquide en cas de processus d’évaporation en couches minces ou en micro-gravité.Deuxièmement, en présence de gravité, un système multi-composants peut devenir instable quelle que soit la direction du chauffage. Si la convection thermique est négligeable, alors nous montrons que le chauffage par la phase vapeur est la configuration la plus instable. Sinon, les deux modes de chauffage sont à même de produire une instabilité. Ce résultat implique que le gradient thermique appliqué doit être inférieur à une valeur seuil pour éviter les instabilités quelle que soit la direction du chauffage.Troisièmement, lorsque l’instabilité apparaît en absence de gravité, des structures n’apparaitront pas dans le cas de fluide pur mais apparaitront dans le cas d’un fluide multi-composants. De même, des structures apparaitront en présence de gravité en fonction du facteur d’aspect du confinement. Les facteurs d’aspect peuvent être choisis pour éviter des structures multi-cellulaires même en cas d’apparition d’instabilités durant l’évaporation.Enfin, des structures oscillantes ne sont pas prédites de façon générale malgré les effets opposés des convections solutale et thermique dans le problème d’évaporation. / This study focuses on understanding the physics of the convective flow resulting from evaporative instability in binary mixtures. This problem has wide applications in spin coating, film deposition, heat pipes, etc. where phase change and convection play a very important role in the design process and also final quality of the product. The physical system of interest consists of a liquid mixture underlying its own vapor sandwiched between two conducting plates with insulated sidewalls in a closed container. The conducting plates are used to apply a vertical temperature gradient while there is no applied concentration gradient in the system. Concentration gradients are induced by the different evaporation rate of the components. In this system it is important to understand how the fluid dynamics and the heat and mass transfer interact competitively to form patterns. The main goal of this work is to identify the conditions for the system going from the conductive no-flow state to a convection state when the applied vertical temperature gradient exceeds a certain value called the critical value.In the system convection arises due to three distinct phenomena; evaporation, density gradients, and interfacial tension gradients. These convective forces are opposed by the diffusion effects that try to keep the system in the conductive no-flow state. The onset point depends upon several variables such as the dimensions of the container, thermo-physical properties of both liquid and vapor phases, mass fraction, and the characteristic of the disturbance given to the system. The effects of each of these variables on the onset point are investigated both in the presence and in the absence of gravity. To represent the physics a complete non-linear mathematical model is developed including momentum, energy, and mass balances in both phases with appropriate boundary conditions. The binary mixture is assumed to be made up of two low weight alcohols such as ethanol and sec-butanol. In the modeling equations the density and the interfacial tension are taken to be function of both temperature and concentration. To identify the onset point the non-linear equations are linearized around a known base state. In this case the base state is the conductive no-flow state. The resulting set of linear equations is solved using a spectral Chebyshev collocation method. Four major results arise from this work. First, in a multi-component system in the absence of gravity, an instability arises only when the system is heated from the vapor side as opposed to evaporation in a single-component. The implication is that evaporative processes in thin layers or in micro-gravity are best conducted with heat from the liquid side if instabilities are to be avoided.Second, in the presence of gravity, a multi-component system may become unstable no matter the direction of heating. If thermal buoyancy is negligible then it is shown in this study that heating from the vapor side is the unstable arrangement. Otherwise either heating style can produce an instability. This result means that the applied temperature difference must be kept below a threshold in order to avoid flow instabilities no matter the heating direction.Third, whenever instability occurs in the absence of gravity, patterns will not result in the case of a pure component but may result in the case of multi-components. Likewise, patterns will result when gravity is taken into account provided the aspect ratio of the container lies in a suitable range. As a result, aspect ratios can be chosen to avoid multi-cellular patterns even if convective flow instabilities arise during evaporation.Lastly, oscillations are not ordinarily predicted despite opposing effects of solutaland thermal convection in the evaporation problem.

A reação de Morita-Baylis-Hillman (MBH) consiste em uma poderosa transformação química, podendo levar à formação de importantes blocos de construção em síntese orgânica. No entanto, a reação de MBH apresenta sérias limitações, principalmente no que diz respeito ao tempo reacional, ao uso de aceptores de Michael β-substituídos e à necessidade de eletrófilos secundários extremamente elétron-deficientes. Dentro desta temática, o presente trabalho investiga uma metodologia tricomponente do tipo Michael-aldol mediada por organocalcogenolatos metálicos, dando origem a adutos de MBH β-organocalcogeno funcionalizados como produto. Nestes estudos foram avaliados diferentes organocalcogenolatos metálicos (S, Se e Te), bem como diferentes aceptores de Michael (eletrófilo primário) e aldeídos (eletrófilo secundário) frente à metodologia. Tal estudo tornou possível a obtenção da (±)-Acaterina, um produto natural biologicamente ativo, em uma única etapa reacional, sendo a síntese mais curta e de maior rendimento até então relatada. Além disso, a metodologia tricomponente foi adaptada à adição de um terceiro eletrófilo no meio reacional, tornando possível a obtenção de derivados de adutos de MBH (ésteres, éteres de silício e carbonatos) também de maneira one-pot (reação tetra-componente do tipo Michael-aldol-O-funcionalização/eliminação de selenóxido). Investigando possíveis novas aplicações dos derivados de MBH produzidos, foi estudada a enolização de ésteres derivados de adutos de MBH onde se observou comportamento nucleofílico do LDA bem como de outras bases fortes. Utilizando cálculos computacionais baseados em DFT, uma coordenada de reação foi calculada para um dos sistemas nos quais LDA foi empregado e, o resultado teórico obtido está de acordo com os resultados obtidos experimentalmente. / The Morita-Baylis-Hillman reaction consists on a powerfull chemical transformation, leading to important building blocks in organic synthesis. However, the MBH presents some serious drawbacks, specially in respect to reactional time, the use of β- substituted Michael acceptors and the need for highly electron-deficient secondary electrophiles. Within this issue, the present work aims the investigation of a tricomponent Michael-aldol reaction mediated by metallic organochalcogenolates, leading to β-organochalcogen functionalized MBH adducts as products. In these studies the behavior of different metallic organochalcogenolates as well as different Michael acceptors (primary electrophile) and aldehydes (secondary electrophiles) were evaluated towards the methodology. Within this study it was possible to synthesize (±)-Acaterin, a natural bioactive compound, in a single reactional step, consisting in the shortest and higher yielding protocol related so far. Moreover, the tricomponent methodology was adapted to the addition of a third electrophile into the reactional media, allowing the preparation of MBH derivatives (esters, silicon ethers and carbonates) also in an one-pot manner (Michael-aldol-O-functionalization/selenoxide elimination four-component reaction). Investigating possible new applications of the produced MBH derivatives, the enolization of MBH esters was studied and a nucleophilic behavior was observed for LDA and for other strong bases. By means of DFT-based computational calculations, a reaction coordinate was calculated for a LDA-based enolization system and the obtained theoretical results are in agreement with the experimentally obtained results.

A reação de Morita-Baylis-Hillman (MBH) consiste em uma poderosa transformação química, podendo levar à formação de importantes blocos de construção em síntese orgânica. No entanto, a reação de MBH apresenta sérias limitações, principalmente no que diz respeito ao tempo reacional, ao uso de aceptores de Michael β-substituídos e à necessidade de eletrófilos secundários extremamente elétron-deficientes. Dentro desta temática, o presente trabalho investiga uma metodologia tricomponente do tipo Michael-aldol mediada por organocalcogenolatos metálicos, dando origem a adutos de MBH β-organocalcogeno funcionalizados como produto. Nestes estudos foram avaliados diferentes organocalcogenolatos metálicos (S, Se e Te), bem como diferentes aceptores de Michael (eletrófilo primário) e aldeídos (eletrófilo secundário) frente à metodologia. Tal estudo tornou possível a obtenção da (±)-Acaterina, um produto natural biologicamente ativo, em uma única etapa reacional, sendo a síntese mais curta e de maior rendimento até então relatada. Além disso, a metodologia tricomponente foi adaptada à adição de um terceiro eletrófilo no meio reacional, tornando possível a obtenção de derivados de adutos de MBH (ésteres, éteres de silício e carbonatos) também de maneira one-pot (reação tetra-componente do tipo Michael-aldol-O-funcionalização/eliminação de selenóxido). Investigando possíveis novas aplicações dos derivados de MBH produzidos, foi estudada a enolização de ésteres derivados de adutos de MBH onde se observou comportamento nucleofílico do LDA bem como de outras bases fortes. Utilizando cálculos computacionais baseados em DFT, uma coordenada de reação foi calculada para um dos sistemas nos quais LDA foi empregado e, o resultado teórico obtido está de acordo com os resultados obtidos experimentalmente. / The Morita-Baylis-Hillman reaction consists on a powerfull chemical transformation, leading to important building blocks in organic synthesis. However, the MBH presents some serious drawbacks, specially in respect to reactional time, the use of β- substituted Michael acceptors and the need for highly electron-deficient secondary electrophiles. Within this issue, the present work aims the investigation of a tricomponent Michael-aldol reaction mediated by metallic organochalcogenolates, leading to β-organochalcogen functionalized MBH adducts as products. In these studies the behavior of different metallic organochalcogenolates as well as different Michael acceptors (primary electrophile) and aldehydes (secondary electrophiles) were evaluated towards the methodology. Within this study it was possible to synthesize (±)-Acaterin, a natural bioactive compound, in a single reactional step, consisting in the shortest and higher yielding protocol related so far. Moreover, the tricomponent methodology was adapted to the addition of a third electrophile into the reactional media, allowing the preparation of MBH derivatives (esters, silicon ethers and carbonates) also in an one-pot manner (Michael-aldol-O-functionalization/selenoxide elimination four-component reaction). Investigating possible new applications of the produced MBH derivatives, the enolization of MBH esters was studied and a nucleophilic behavior was observed for LDA and for other strong bases. By means of DFT-based computational calculations, a reaction coordinate was calculated for a LDA-based enolization system and the obtained theoretical results are in agreement with the experimentally obtained results.

There are many applications of small organic compounds, e.g. as drugs or as tools to study biological systems. Once a compound with interesting biological activity has been found, medicinal chemists typically synthesize small libraries of compounds with systematic differences to the initial “hit” compound. By screening the new ensemble of compounds for their ability to perturb the biological system, insights about the system can be gained. In the work presented here, various ways to synthesize small libraries of ring-fused 2‑pyridones have been developed. Members of this class of peptidomimetic compounds have previously been found to have a variety of biological activities, e.g. as antibacterial agents targeting virulence, and as inhibitors of the aggregation of Alzheimer b‑peptides. The focus in this work has been to alter the core skeleton, the central fragment, of the previously discovered biologically active 2‑pyridones and evaluate the biological effects of these changes. Several new classes of compounds have been constructed and their preparations have included the development of multi-component reactions and a method inspired by diversity-oriented synthesis. Some of the new compounds have been evaluated for their effect on the fibrillation of different amyloid proteins. Both the Parkinson-associated amyloid protein a-synuclein and the bacterial protein CsgA that is involved in bacterial biofilm formation are affected by subtle changes of the compounds’ central fragments. This is an example of the usefulness of central-fragment alterations as a strategy to probe structure-activity relationships, and the derived compounds may be used as tools in further study of the aggregation of amyloid proteins.

L'objectif de cette thèse est de développer un ensemble de modèles numériques afin de simuler les processus physico-chimiques dans la chambre de combustion ainsi que dans le système de post-traitement des gaz d'échappement des moteurs à combustion interne. Dans la première partie de cette thèse, deux nouveaux modèles d'évaporation de gouttelettes et de film liquide multi-composants sont proposés. Dans le modèle d'évaporation des gouttelettes, une nouvelle expression du débit d'évaporation a été proposée. Il a été montré que la prise en compte du flux de chaleur dû à la diffusion d'enthalpie des espèces est primordiale dans le bilan d'énergie à l'interface de la goutte. De plus, les investigations numériques ont montré l'importance de la prise en compte d'une équation d'état de gaz réel dans les conditions de hautes pressions et / ou de basses températures ambiantes. Un modèle d'évaporation multi-composant de film liquide a ensuite été développé sur la base du modèle d'évaporation de film mono-composant déjà mis en oeuvre dans le code industriel IFP-C3D. En particulier, les lois de paroi ont été généralisées pour l'évaporation du film multi-composant de manière similaire au modèle de l'évaporation des gouttelettes. Il a été montré l'importance de la température de la paroi dans le processus d'évaporation d'un film liquide. Contrairement à l'évaporation des gouttes, les investigations numériques effectuées ont montré que l'utilisation d'une équation d'état de gaz parfait conduit à des résultats proches de ceux qui sont obtenus en utilisant une équation d'état de gaz réel. Ceci se traduit par un gain en temps de calculs important. La deuxième partie de la thèse utilise les modèles d'évaporation, développés dans la première partie de la thèse, avec un nouveau modèle de thermolyse développé afin de produire de l'ammoniac nécessaire pour le système SCR. Dans la présente étude, l'ammoniac est produit à partir de la solution aqueuse d'urée injectée dans la ligne de tuyau d'échappement. L'eau s'évapore et l'urée se décompose en ammoniac nécessaire pour le système SCR. L'évaporation de l'eau est modélisée avec les modèles d'évaporation proposés dans la première partie de cette thèse, avec quelques modifications afin de prendre en compte l'influence de l'urée sur l'évaporation de l'eau. Un nouveau modèle de thermolyse multi-étape pour l'urée a été ensuite implanté dans IFP- 3D afin de simuler la distribution de l'ammoniac gazeux à l'entrée de système de dépollution SCR. Ce modèle est également capable de simuler la formation de sous- roduits (dépôt solide) de la thermolyse d'urée. Les résultats numériques des modèles développés ont permis de montrer le potentiel des développements réalisés au cours de ce travail dans le cadre d'applications industrielles. / The aim of the present thesis is to develop a set of numerical models in order to simulate the physical and chemical processes in combustion chamber as well as in exhaust gas after-treatment system of internal combustion engines. In the first part of the thesis, two new multi- omponent evaporation models for droplet and liquid film are proposed. In the droplet evaporation model, a new expression of the evaporation rate has been proposed. It has been shown that taking into account the heat flux due to the enthalpy diffusion of species is of primary significance in the energy balance at the droplet surface. In addition, numerical investigations have shown the importance of considering a real gas equation of state in the high pressure and/or low temperature conditions. A multi-component liquid film evaporation model has then been developed based on the single-component film evaporation model already implemented in IFP-C3D code. Particularly, the wall laws have been generalized for the multi-component film evaporation taking into account the mentioned features applied to the droplet evaporation model. The importance of surface temperature in the evaporation of liquid film has also been shown. Contrary to the droplet evaporation, the numerical investigations on film evaporation have shown that using an ideal mixture equation of state leads to results similar to those obtained using a real gas equation of state. The second part of the thesis uses the evaporation models, developed in the first part of the thesis, along with a new developed thermolysis model in order to produce the ammonia needed for the SCR system. In the present study, ammonia is produced from the urea-water solution injected into the exhaust pipe line. Water evaporates and urea decomposes to ammonia needed for SCR system. The evaporation of water is modeled with the proposed evaporation models in the first part of the present thesis with some modifications in order to take into account the influence of urea on the water evaporation. New multi-step thermolysis model for urea is then implemented in the IFP-C3D code in order to simulate the distribution of gaseous ammonia at the entrance of SCR system. The present model is also able to simulate the formation of solid by-products from urea thermolysis. The numerical results of the developed models allow us to assess the contribution of the developments made during this work in the context of industrial applications.

This master‘s thesis deals with the solution of the production of the given part "APZ13". The structural analysis of the component is followed by the choice of the available manufacturing technology. The following is a theoretical description of the chosen technology and injection mold. Its solution is practically described in the following chapter and then the creation of TPV documentation of the whole project. The conclusion of this master’s thesis is a technical-economic evaluation of the chosen technology and discussion.

Multi-component coatings and high entropy alloys have in recent years attracted great interest for research, since they have shown to exhibit properties greater than the com- ponents of their parts. Today’s climate challenges requires transitioning from fossil fuels to renewable energy sources which demands use of new technology and new innovations. The hydrogen fuel cell is a technology which produces no carbon emissions, and the drive for innovation has led researchers to apply multi-component (high entropy alloys) coatings to invent the next generation hydrogen fuel cells and help the transition to renewable energy sources. This thesis has investigated the process-structure-property relationships of four deposi- tion growth parameters: target current (Itarget), argon pressure (PAr). substrate bias (Vsubstrate) and deposition time (tdeposition) on TiNbZrTa-coatings, grown by magnetron sputtering using an industrial deposition system. The range of the parameters have been: Itarget from 2.5 to 6 A, PAr from 1 to 17 mTorr, Vsubstrate from 30 to 200 V and tdeposition from 3.6 to 12 minutes (depending on Itarget). Coatings have been grown on Si (001) and stainless steel 304 and 316L substrates. The coating microstructure was analyzed by X-ray diffraction and electron microscopy. The results have yielded that all coatings are equimolar and that the coatings exhibit three different morphologies, two different topologies and two different corresponding structures. The different morphologies are wave, coarse columnar and fine columnar morphology. The two topologies are nodular and dune surface topology. The two different structures are a solid solution BCC (110) phase and an amorphous or nanocrystalline phase. The results indicate that parameters affecting the temperature of the substrate (Tsubstrate) is the prime decider for the final morphology of the coatings. High Itarget and Vsubstrate, low PAr and long tdeposition all increases Tsubstrate and results in a coating which exhibits a fine columnar morphology, dune topology and a solid solution BCC phase. These types of coatings have also proven to have improved corrosion resistance compared to the other type of coatings seen in this thesis. The other kind of coating is grown with low Itarget and Vsubstrate, high PAr and short tdeposition, which causes minimal increase of Tsubstrate. These growth parameters result in a coating with coarse columnar morphology, nodular topology and amorphous or nanocrystalline phase, with less corrosion resistance. / FunMat II

Nowadays, earthquakes are one of the most catastrophic natural events that have a significant human, socio-economic and environmental impact. Besides, based on both observations of damage following recent major/moderate seismic events and numerical/experimental studies, it clearly emerges that critical non-structural components (NSCs) that are ubiquitous to most industrial facilities are particularly and even disproportionately vulnerable to those events. Nonetheless and despite their great importance, seismic provisions for industrial facilities and their process equipment are still based on the classical load-and-resistance factor design (LRFD) approach; a performance-based earthquake engineering (PBEE) approach should, instead, be preferred. Along this vein, in recent years, much research has been devoted to setting computational fragility frameworks for special-risk industrial components and structures. However, within a PBEE perspective, studies have clearly remarked: i) a lack of definition of performance objectives for NSCs; ii) the need for fully comprehensive testing campaigns data on coupling effects between main structures and NSCs. In this respect, this doctorate thesis introduces a computational framework for an efficient and accurate seismic state-dependent fragility analysis; it is based on a combination of data acquired from an extensive experimental shake table test campaign on a full-scale prototype industrial steel frame structure and the most recent surrogate-based UQ forward analysis advancements. Specifically, the framework is applied to a real-world application consisting of seismic shake table tests of a representative industrial multi-storey frame structure equipped with complex process components, carried out at the EUCENTRE facility in Italy, within the European SPIF project: Seismic Performance of Multi-Component Systems in Special Risk Industrial Facilities. The results of this experimental research campaign also aspire to improve the understanding of these complex systems and improve the knowledge of FE modelling techniques. The main goals aim to reduce the huge computational burden and to assess, as well, when the importance of coupling effects between NSCs and the main structure comes into play. Insights provided by innovative monitoring systems were then deployed to develop and validate numerical and analytical models. At the same time, the adoption of Der Kiureghian's stochastic site-based ground motion model (GMM) was deemed necessary to severely excite the process equipment and supplement the scarcity of real records with a specific frequency content capable of enhancing coupling effects. Finally, to assess the seismic risk of NSCs of those special facilities, this thesis introduces state-dependent fragility curves that consider the accumulation of damage effects due to sequential seismic events. To this end, the computational burden was alleviated by adopting polynomial chaos expansion (PCE) surrogate models. More precisely, the dimensionality of a seismic input random vector has been reduced by performing the principal component analysis (PCA) on the experimental realizations. Successively, by bootstrapping on the experimental design, separate PCE coefficients have been determined, yielding a full response sample at each point. Eventually, empirical state-dependent fragility curves were derived.

Six new multi-component crystals between 4-phenylpyridine and substituted benzoic acids (3-nitrobenzoic acid, 3,5-dinitrobenzoic acid, gallic acid, 4-aminobenozic acid, salicylic acid and 2-aminobenzoic acid) were created and characterized crystallographically to investigate the influence of chemical and structural factors on the hydrogen location between the two components. While the expected intermolecular interactions are formed between the acid and pyridine group in most cases, the gallic acid structure is anomalous forming an unexpected salt with pyridine to hydroxyl interactions. Calculations of the hydrogen bonding motifs indicate that the level of proton transfer (e.g. salt versus co-crystal formation) is not solely a function of the dimer geometry but influenced by the local crystallographic environment. Analysis of the crystal structures indicates the strength of the hydrogen bonding into this motif alters the expected protonation state from chemical considerations.

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