High-resolution molecular spectroscopy has been used to study acetylene line parameters and emission spectra of hydrogen cyanide. All acetylene spectra were recorded in our laboratory at the University of Lethbridge using a 3-channel tuneable diode laser spectrometer. N2-broadened line widths and N2-pressure induced line shifts have been measured for transitions in the v1+v3 band of acetylene at seven temperatures in the range 213–333K to obtain the temperature dependences of broadening and shift coefficients. The Voigt and hard-collision line profile models were used to retrieve the line parameters. The line-broadening and line-shift coefficients as well as their temperature-dependent parameters have been also evaluated theoretically, in the frame work of a semi-classical approach based on an exponential representation of the scattering operator, an intermolecular potential composed of electrostatic quadrupole–quadrupole and pairwise atom–atom interactions as well as on exact trajectories driven by an effective isotropic potential. The experimental results for both N2-broadening and shifting show good agreement with the theoretical results. We have studied the line intensities of the 1νl20←0νl20 band system from the HCN emission spectrum. The infrared emission spectrum of H12C14N was measured at the Justus-Liebig University, Giessen, Germany. The emission spectrum was analyzed with the spectrum analysis software Symath running using Mathematica as a platform. This approach allowed us to retrieve information on band intensity parameters. / viii, 112 leaves : ill. ; 29 cm

L’hydrogénation sélective de l’acétylène est un processus fondamental pour l’industrie pétrochimique qui permet la purification de l’éthylène utilisé dans les réactions de polymérisation. Ce processus est promu par des catalyseurs au palladium, qui présentent une bonne sélectivité en éthylène par rapport au produit d’hydrogénation totale, c’est-à-dire l’éthane. Les catalyseurs de palladium pur sont malheureusement désactivés par des oligomères qui se forment comme sous-produits de la réaction d’hydrogénation. Les catalyseurs d’usage industriel sont, pour cette raison, plutôt des alliages de palladium avec d’autres métaux, comme par exemple, l’argent. Ces alliages réduisent la production des oligomères, sans pour autant les supprimer complètement. Ce travail de thèse a été focalisé sur la compréhension à l’échelle moléculaire de la formation de ce mélange d’oligomères, souvent appelée « huile verte ». Pour commencer, une approche de champ moyen a été développée pour déterminer rapidement l’état de la surface catalytique de l’alliage Pd-Ag en condition de réaction. Ce modèle a montré que l’acétylène est capable de réorganiser la couche de la surface et de générer des îles de palladium. Pour confirmer cette prédiction, nous avons effectué des simulations Monte Carlo en utilisant un Hamiltonien modèle. Ces calculs ont produits des résultats similaires au modèle analytique simple. Ayant attribué la formation des oligomères aux domaines de palladium ainsi obtenus, les étapes de d’oligomérisation ont été étudies et comparés à celles qui décrivent l’hydrogénation de l’acétylène. Les calculs, réalisé avec l’approximation de la théorie de la fonctionnelle de la densité (DFT), ont montré que la formation des oligomères est compétitive avec l’hydrogénation. En plus, les oligomères sont plus faciles à hydrogéner que l’acétylene et pourraient, donc, impacter négativement sur l’hydrogénation sélective de l’acétylène. Le rôle exact des îles de palladium sous conditions réalistes est encore à clarifier, sachant que le palladium est recouvert d’une grande variété d’espèces chimiques. Les techniques d’intelligence artificielle peuvent aider à atteindre ce but : nous avons ainsi démontré qu’il est possible d’interpoler les résultats des calculs DFT d’une façon automatique et de décrire l’énergie du système en série de coefficients « cluster ». Ceci permet de prendre en compte les interactions latérales entre espèces chimiques à la surface du palladium. / Selective hydrogenation of acetylene in ethylene-rich flows is a fundamental process in the petrochemical industry since it allows the purification of ethylene for polymer applications. The reaction is catalyzed by Pd, which features acceptable selectivity towards ethylene compared to the total hydrogenation product, ethane. Pure Pd is, however, deactivated by oligomeric byproducts, known as ”green oil” in the literature. Therefore, most industrial catalysts are Pd-Ag alloys, where Ag helps to suppress the secondary reactions. This work addresses the formation of initial oligomers on Pd and Ag-Pd catalysts. A mean field based theoretical model was built to efficiently screen the topology of the topper most layer of the alloy catalyst under relevant conditions. This model gave evidence for strongly favored Pd island formation. To confirm this result, the system was then re-investigated by means of Monte Carlo simulations including the effect of segregation. Emergence of large domains of Pd were confirmed over large ratios of Ag to Pd. Green oil is expected to form on these catalytically active islands. To obtain a detailed view on the oligomerization process, activation energies were computed both for hydrogenation and oligomerization steps by periodic density functional theory on Pd(111). Oligomerization was found to be competitive with hydrogenation, with the hydrogenation of the oligomers being among the fastest processes. The role of Pd domains to green oil formation is still to be clarified under realistic conditions, where the surface is covered by many different species. A step forward to this goal was taken by developing a machine-learning tool which automatically interpolates model Hamiltonians on graphical lattices based on DFT computations, accounting for lateral interactions and distorted adsorption modes on crowded surfaces.

Quantum optimal control theory is applied to find optimal pulses for controlling the motion of an ion and a molecule for two different applications. Those optimal pulses enable the control of the dynamics of the system by driving the atom or the molecule from an initial state to desired states.The evolution equations obtained by means of the quantum optimal control theory are resolved iteratively using a monotonic convergent algorithm. A number of simulation parameters are varied in order to get the optimal pulses including the duration of the pulses, the time step of the time grid, a penalty factor that limits the maximal intensity of the fields, and a guess pulse which is used to start the optimal control.The optimal pulses obtained for each application are analyzed by Fourier transform, and also by looking at the time evolution of the populations that they generate in the system.The first application is the preparation of specific vibrational states of acetylene that are usually not reachable from the ground state, and that would remain unpopulated by usual spectroscopy. Relevant state energies and transition dipole moments are extracted from the experimental literature and especially from the global acetylene Hamiltonian conferring an uncommon precision to the control simulation. The control starts from the ground state. The target states belongs to the polyad Ns=1, Nr=5 of acetylene which includes two vibrational dark states and one vibrational bright state. First, the simulation is performed with the Schrödinger equation and in a second step, with the Liouville--von Neumann equation, as mixed states are prepared. Indeed, the control starts from a Boltzmann distribution of population in the rotational levels of the vibrational ground state chosen in order to simulate an experimental condition. But the distribution is truncated to limit the computational effort. One of the dark states appears to be a potential target for a realistic experimental investigation because the average population of the Rabi oscillation remains high and decoherence is expected to be weak. The optimal pulses obtained have a high fidelity, have a spectrum with well-resolved peak frequencies, and their experimental feasibility seems achievable within the current abilities of experimental laboratories.The second application is to propose an experimental realization of a microscopic physical device able to simulate quantum dynamics. The idea is to use the motional states of a Cd^+ ion trapped in an anharmonic potential to realize a quantum dynamics simulator of a single-particle Schrödinger equation. In this way, the motional states store the information and the optimal pulse manipulates this information to realize operations. In the present case, the simulated dynamics was the propagation of a wave packet in a harmonic potential. Starting from an initial quantum state, the pulse acts on the system to modify the motional states of the ion in such a way that the final superposition of motional states corresponds to the results of the dynamics. This simulation is performed with the Liouville--von Neumann equation and also with the Lindblad equation as dissipation is included to test the robustness of the pulse against perturbations of the potential. The optimal pulses that are obtained have a high fidelity which shows that the ion trap system has correctly realized the quantum dynamics simulation. The optimal pulses are valid for any initial condition if the potential of the simulation or the mass of the propagated wave packet is unchanged. / La théorie du contrôle optimal quantique est utilisée pour trouver des impulsions optimales permettant de contrôler la dynamique d'un atome et d'une molécule les menant d'un état initial à un état final. Les équations d'évolution obtenues grâce au contrôle optimal limitent l'intensité maximale de l'impulsion et sont résolues itérativement grâce à l'algorithme de Zhu--Rabitz. Le contrôle optimal est utilisé pour réaliser deux objectifs. Le premier est la préparation d'états vibrationnels de l'acétylène qui sont généralement inaccessibles par transition au départ de l'état vibrationnel fondamental. Ces états, appelés états sombres, sont les états cibles de la simulation. Ils appartiennent à la polyade Ns=1, Nr=5 de l'acétylène qui en contient deux ainsi qu'un état, dit brillant, qui lui est accessible depuis l'état fondamental. Les énergies des états du système et les moments de transitions dipolaires sont déterminés à partir d'un Hamiltonien très précis qui confère une précision inhabituelle à la simulation. Un des états sombres apparaît être un candidat potentiel pour une réalisation expérimentale car la population moyenne de cet état reste élevée après l'application de l'impulsion.Les niveaux rotationnels des états vibrationnels sont également pris en compte.Les impulsions optimales obtenues ont une fidélité élevée et leur spectre en fréquence présente des pics résolus.Le deuxième objectif est de proposer la réalisation expérimentale d'un dispositif microscopique capable de simuler une dynamique quantique. Ce travail montre qu'on peut utiliser les états de mouvement d'un ion de Cd^+ piégé dans un potentiel anharmonique pour réaliser la propagation d'un paquet d'onde dans un potentiel harmonique. Ce dispositif stocke l'information de la dynamique simulée grâce aux états de mouvements et l'impulsion optimale manipule l'information pour réaliser les propagations. En effet, démarrant d'un état quantique initial, l'impulsion agit sur le système en modifiant les états de mouvements de l'ion de telle sorte que la superposition finale des états de mouvements corresponde aux résultats de la dynamique. De la dissipation est incluse pour tester la robustesse de l'impulsion face à des perturbations du potentiel anharmonique. Les impulsions optimales obtenues ont une fidélité élevée ce qui montre que le système a correctement réalisé la simulation de dynamique quantique. / Doctorat en Sciences / info:eu-repo/semantics/nonPublished

Les travaux présentés dans ce mémoire concernent la caractérisation par infrarouge à transformée de Fourier (FTIR) et par spectroscopie d’émission optique (SEO) des réactions chimiques entre post-décharges et précurseurs organosiliciés, avec comme exemple le cas du 3-aminopropyltriéthoxysilane (APTES). Le but est d’obtenir la rétention la plus élevée possible de fonctions amine -NH2 dans les revêtements ou dans les nanoparticules synthétisées. Tout d’abord, un état de l’art des post-décharges Ar-N2 et Ar-O2 et leurs applications est présenté ainsi que la cinétique d’interaction de l’APTES dans ces post-décharges, mettant en évidence le rôle des mélanges plasmagènes sur la décomposition du précurseur et sur la nature des films déposés. Ensuite l’étude de la décomposition de l’APTES dans une post-décharge Ar-N2 est réalisée. Les analyses par SEO et par FTIR in situ montrent le rôle des atomes d’azote N dans la formation des différents sous-produits, à savoir HCN, CO et C=O. Les nanoparticules synthétisées contiennent peu d’amine primaire, et présentent une concentration non négligeable d’azote sous forme d’amide secondaire. Dans le cas de l’étude de la décomposition de l’APTES dans la post-décharge Ar-O2 en mode pulsé, une tendance se dessine : les nanoparticules synthétisées en phase gazeuse lorsque les rapports cycliques augmentent ont une composition qui s’appauvrit en azote et en carbone mais s’enrichit en oxygène. Les groupements NH2 initiaux sont fortement convertis en groupement amide. Les nanoparticules synthétisées avec des rapports cycliques élevés ont des compositions différentes de celles des films minces déposés sur les parois, plus proches de la silice et ce en raison de la gravure par l’oxygène atomique qui les affecte davantage. Le comportement spécifique des atomes d’oxygène et d’azote en post-décharge rend difficile la rétention des amines dans les polymères plasmas. Enfin nous avons terminé par une étude de l’hydrodynamique dans le cas de l’interaction entre l’acétylène et une post-décharge Ar-O2 et établi l’importance de l’écoulement sur toute approche visant à faire des mesures FTIR résolues temporellement / The present work deals with the characterization by Fourier transform infrared spectroscopy (FTIR) and by optical emission spectroscopy of chemical reactions between a post-discharge and an organosilicon precursor: the 3-aminopropyltriethoxysilane (APTES). The aim is to keep the highest retention of amine functions -NH2 in coatings or in the synthesized nanoparticles. First, a state of the art of Ar-N2 and Ar-O2 post-discharges and their applications is presented as well as the kinetics of the interaction of APTES in these post-discharges, highlighting the role plasma gases on the decomposition of the precursor and the nature of the deposited films. Then, the study of the decomposition of APTES in an Ar-N2 post-discharge is carried out. Analysis by optical emission spectroscopy (OES) and in situ FTIR show the role of the nitrogen atoms N in the formation of various main by-products, namely HCN, CO and C=O. The synthesized nanoparticles contain few primary amines, and have a significant concentration of nitrogen in the form of secondary amide. In the case of interaction APTES with pulsed Ar-O2 afterglow, there is one main trend: the nanoparticles synthesized in the gas phase when the duty cycle increases have a composition that decreases in nitrogen and carbon but increases in oxygen. The -NH2 groups are efficiently converted into amide groups. The nanoparticles synthesized with high duty cycle exhibit compositions that are different from those of thin films deposited on the walls, the latter being close to silica because of the etching by atomic oxygen, which affects them more. The specific behavior of oxygen and nitrogen atoms in post-discharge makes difficult the retention of a high level of amines in plasma polymers. Finally, we finished with a study of the hydrodynamics in the case of the interaction of acetylene with an Ar-O2 post-discharge and proved the key role of the flow for any approach aiming at getting time-resolved FTIR measurements

The design and performance evaluation of in-duct, isokinetic samplers capable of testing flat sheet, nuclear-grade High Efficiency Particulate Air (HEPA) filters simultaneously with a radial filter testing system is discussed in this study. Evaluations within this study utilize challenge aerosols of varying particle diameters and masses such as hydrated alumina, Arizona test dust, and flame-generated acetylene soot. Accumulated mass and pressure drop for each in-duct sampler is correlated to the full-scale radial filter accumulated mass from initial to 10 in w. c. of loading. SEM imaging of samples at 25%, 50%, 75% and 100% loading verifies particle sizes with instrumentation used, revealing filter clogging resulting from particle impaction and interception. The U.S Department of Energy requires prototype nuclear-grade HEPA filters to be qualified under ASME AG-1 standards. The data obtained can be used to determine baseline performance characteristics on pleated radial filter medium for increased loading integrity and lifecycle endurance.

Indiana University-Purdue University Indianapolis (IUPUI) / Polyacetylenic natural products, compounds containing multiple carbon-carbon triple bonds, have been found in a large collection of organisms. Radiochemical tracer studies have indicated that these bioactive metabolites are synthesized from fatty acid precursors through a series of uncharacterized desaturation and acetylenation steps. To date, there are three main pathways believed to be involved in acetylenic natural product biosynthesis. However, it is apparent that the crepenynic acid pathway is the origin of a vast majority of the known plant and fungal acetylenic products. This investigation provides concrete evidence that the polyacetylenic natural products found in the fungus Fistulina hepatica and the medicinal plant species Echinacea purpurea are biosynthesized from crepenynic acid. Through heterologous expression in Yarrowia lipolytica, two acetylenases capable of producing crepenynic acid were identified from E. purpurea. Furthermore, heterologous expression of two diverged desaturases isolated from F. hepatica, uncovered a ∆12-acetylenase and the first multifunctional enzyme capable of ∆14-/∆16- desaturation and ∆14-acetylenation.

The identification and quantification of atoms, molecules, or ions concentrations in gaseous samples are in great demand for medical, environmental, industrial, law enforcement and national security applications. These applications require in situ, high-resolution, non-destructive, sensitive, miniature, inexpensive, rapid detection, remotely accessed, real time and continuously operating chemical sensing devices. The aim of this work is to design a miniature optical sensing device that is capable of detecting and measuring chemical species, compatible with being integrated into a large variety of monitoring systems, and durable enough to be used under extreme conditions. The miniature optical sensor has been realized by employing technologies from the optical communication industry and spectroscopic methods and techniques. Fused silica capillary tubing along with standard communication optical fibers have been utilized to make miniature gas sensor based on near-infrared spectroscopy for acetylene gas detection. In this work, the basic principles of infrared spectroscopy are reviewed. Also, the principle of operation, fabrication, testing, and analysis of the proposed sensor are discussed in details. / Master of Science

Red alder (Alnus rubra Bong.) is the only tree in British Columbia and the Northwest US to engage in actinorhizal symbiosis to fix atmospheric nitrogen. This study was conducted to explore the plasticity in growth and physiology among 58 17-year-old red alder families in response to variation in climate in two common garden plots, one at Bowser, BC and one at Terrace, BC. Physiological assessments included height and diameter growth, bud flush, water use efficiency as measured by δ13C, cold hardiness as measured by controlled freezing and electrolyte leakage, autumn leaf senescence, and instantaneous and seasonally integrated rates of nitrogen fixation as measured by acetylene reduction and natural abundance δ15N isotope analysis, respectively. Significant differences were identified among families for growth (height and diameter), bud burst stage, leaf senescence, cold hardiness, and bud nitrogen content. No significant differences among families were identified for water use efficiency as measured by δ13C, or for rates of nitrogen fixation as measured by either acetylene reduction or natural abundance δ15N. This study identified possible adaptive differences among red alder genotypes, especially in traits such as bud flush timing, cold hardiness, or nitrogen fixation and their respective contributions to growth. These differences often reflected a tradeoff between growth and the ability to tolerate an extreme environment. Cold hardiness results indicate that red alder families are well adapted to their climate of origin, and may not be able to acclimate sufficiently to a northward assisted migration of genotypes. Nitrogen fixation results demonstrated gaps in our current knowledge of Frankia distribution and impact on the actinorhizal symbiosis in British Columbia. / Graduate

In this dissertation, different approaches have been employed to address the quest of understanding the formation and growth mechanisms of carbon-containing molecular ions with relevance to astrochemistry. Ion mobility mass spectrometry and DFT computations were used to investigate how a second nitrogen in the pyrimidine ring will affect the formation of a covalent bond between the benzene radical cation and the neutral pyrimidine molecule, after it was shown that a stable covalent adduct can be formed between benzene radical cation and the neutral pyridine. Evidence for the formation of a more stable covalent adduct between the benzene radical cation and the pyrimidine is reported here. The effect of substituents on substituted-benzene cations on their solvation by an HCN solvent was also investigated using ion mobility mass spectrometry and DFT computations were also investigated. We looked at the effect of the presence of electron-withdrawing substituents in fluorobenzene, 1,4 di- fluorobenzene, and benzonitrile on their solvation by up to four HCN ligands, and compared it to previous work done to determine the solvation chemistry of benzene and phenylacetylene by HCN. We report here the observed increase in the binding of the HCN molecule to the aromatic ring as the electronegativity of the substituent increased. We also show in this dissertation, DFT calculations that reveal the formation of both hydrogen-bonded and electrostatic isomers, of similar energies for each addition to the ions respectively. The catalytic activity of the 1st and 2nd row TM ions towards the polymerization of acetylene done using the reflectron time of flight mass spectrometry and DFT calculations is also reported in this dissertation. We explain the variation in the observed trend in C-H/C-C activity of these ions. We also report the formation of carbide complexes by Zr+, Nb+, and Mo+, with the acetylene ligands, and show the thermodynamic considerations that influence the formation of these dehydrogenated ion-ligand complexes. Finally, we show in this dissertation, a novel ionization technique that we employed to generate ions that could be relevant to the interstellar and circumstellar media using the reflectron time of flight mass spectrometry.

Um importante diferencial competitivo das empresas distribuidoras de energia elétrica é a gestão da utilização dos seus ativos elétricos. Dentre eles destaca-se o transformador de potência em função de sua importância estratégica no fornecimento de energia aos grandes centros de carga. Para minimizar os impactos operacionais e sociais associados às interrupções constantemente monitoradas para que haja controle efetivo e garantia de funcionamento adequado e otimizado. O monitoramento das suas principais características é um ponto crítico que deve ser constantemente aprimorado, pela indiscutível importância destes ativos elétricos na continuidade do fornecimento de energia elétrica. Este trabalho apresenta proposta para avaliação em tempo real de falhas em transformadores de potência, para que sejam monitorados remotamente pela distribuidora, através do seu respectivo centro de operação do sistema elétrico, propiciando assertividade e rápida tomada de decisão gerencial em ocorrências de falhas internas, reduzindo os custos associados à interrupção do fornecimento de energia elétrica, diminuindo significativamente os tempos de restabelecimento do fornecimento e consequentemente minimizando impactos nos principais Indicadores de qualidade operacional da distribuidora. / An important competitive edge of electric power distribution companies is their electric assets utilization management. Among them stands outs the power transformers because of its strategic importance in the energy supply to high demand areas. To minimize operational and social impacts associated to the electric energy supply interruptions these equipments must to have their main characteristics constantly monitored to have effective control and optimizer functioning warranty. The main characteristics monitoring is a critical point which must be constantly improved, for the unquestionable importance of these electric assets in the electric energy supply continuity. This work shows a proposal to the real time power transformer failure, to remote monitoring by the utilities thru its respective electric system operation center, enabling assertively and fast management decision making in internal failure occurrences, reducing costs associated with electric energy supply interruption, decreasing the supply reestablishing times and consequently minimizing the impacts on the main distribution operational quality indicators.