<p>The role of the dimensionality and strain state of metallic lattices on the phase behavior of dissolved hydrogen was explored. Metallic superlattices with well defined hydrogen absorption potential on the nm scale, were utilized as test systems. The solubility isotherms of hydrogen in Fe/V(001), MoV/V(001), and Nb/W(110) superlattices were measured by a resistometric method, and the hydrogen-induced changes of the structures were measured by <i>in-situ</i> X-ray diffraction. In the V based superlattices, the long-ranged ordered bulk V hydride phase β-V₂H is absent, which is attributed to the finite-size of V lattice. The intrinsic strain-state of the hydrogen dissolving layers was found to have a strong effect on the interaction between metal and hydrogen as well as on the hydrogen-hydrogen (H-H) interaction. For low hydrogen content in the V layers, the compressive strain resulted in a strong enhancement of the H-H interaction, while a tensile strain appeared to diminish the H-H interaction. This is due to different site occupancy of hydrogen for different strain states, which depending on the relation between the symmetries of hydrogen induced global and local strain fields, gives rise to different elastic H-H interaction. Moderately strained V layers exhibited a strong attractive H-H interaction over a broad concentration range. In the concentration ranges where attractive H-H interaction was established, the hydrogen atoms appeared to be strongly correlated on a microscopic length scale. In the Nb based superlattices, the critical temperature for the α–α’ transition was found to be suppressed as a result of the clamping of the film plane by the film-substrate coupling. An exception from this could be noticed when the intrinsic compressive strain were reduced.</p>

The role of the dimensionality and strain state of metallic lattices on the phase behavior of dissolved hydrogen was explored. Metallic superlattices with well defined hydrogen absorption potential on the nm scale, were utilized as test systems. The solubility isotherms of hydrogen in Fe/V(001), MoV/V(001), and Nb/W(110) superlattices were measured by a resistometric method, and the hydrogen-induced changes of the structures were measured by in-situ X-ray diffraction. In the V based superlattices, the long-ranged ordered bulk V hydride phase β-V2H is absent, which is attributed to the finite-size of V lattice. The intrinsic strain-state of the hydrogen dissolving layers was found to have a strong effect on the interaction between metal and hydrogen as well as on the hydrogen-hydrogen (H-H) interaction. For low hydrogen content in the V layers, the compressive strain resulted in a strong enhancement of the H-H interaction, while a tensile strain appeared to diminish the H-H interaction. This is due to different site occupancy of hydrogen for different strain states, which depending on the relation between the symmetries of hydrogen induced global and local strain fields, gives rise to different elastic H-H interaction. Moderately strained V layers exhibited a strong attractive H-H interaction over a broad concentration range. In the concentration ranges where attractive H-H interaction was established, the hydrogen atoms appeared to be strongly correlated on a microscopic length scale. In the Nb based superlattices, the critical temperature for the α–α’ transition was found to be suppressed as a result of the clamping of the film plane by the film-substrate coupling. An exception from this could be noticed when the intrinsic compressive strain were reduced.

<p>An elastic interaction theory, taking both slip and uplift effects into account, is presented for a composite beam with a solid concrete slab connected to a steel beam. The results of this theory , which involves the solution of a sixth order differential equation, are compared with the results of Newmark's theory which only considers interfacial slip effects and involves the solution of a second order differential equation.</p> <p>An experimental study of a full scale composite beam incorporating a cellular deck under a two point load and simple support conditions is also reported. In addition, the experimental results are compared with the computed results obtained from an existing finite difference formulation.</p> / Master of Engineering (ME)

Le Modèle Standard de la physique des particules décrit les interactions des particules sub-atomiques à travers les interactions fortes, faibles et électromagnétiques.Toutefois, il est clair que cette théorie ne constitue pas une description complète de la Nature. Mais le fait expérimental que les neutrinos changent de saveur au cours de leur propagation(oscillation des neutrinos) implique qu'ils ont une masse non nulle. Le travail de cette thèse se concentre sur l'expérience d'oscillation T2K : une expérience à longue ligne de base installée au Japon. % qui est détaillés dans le Chapitre 2. Pour la première fois T2K a pu observer l'apparition de neutrinos de saveur électronique dans le faisceau principalement composé de neutrinos muoniques etobtenir les premières contraintes sur la violation de la symétrie Charge-Parité. Il permet également de mesurer précisément les paramètres d'oscillations θ₁₃ , θ₂ ₃ et Δm²₂ ₃ .Cela nécessite une excellente compréhension du détecteur et des modèles d'interactions des neutrinos. Cette thèse se concentre sur ces deux objectifs : réduire les systématiques liées audétecteur et approfondir nos connaissances sur l'interaction des neutrinos avec la matière.Le groupe CEA, dans lequel je suis impliqué, est responsable de la maintenance et de l'opération des Chambres à Projections Temporelles (TPC) du détecteur proche (ND280).Elles permettent l'identification des particules chargées produites par l'interaction des neutrinos dans le detecteur et la mesure de leur impulsion.Une partie de mon travail a consisté en l'étude des TPCs et en particulier de l'alignement des modules MicroMegas installés sur les plans de lecture. En effet tout défaut d'alignement entre différents modules peut causer un biais sur la mesure del'impulsion des particules traversant la TPC. Les neutrinos sont étudiés grâce à l'observation de l'état final de leur interaction avec la matière. Les modèles d'interactions doivent alors être parfaitement bien compris,car les expériences d'oscillation présentes et futures approchent d'une phase où notre connnaissance des interactionsdes neutrinos devient un facteur limitant pour la détermination des paramètres d'oscillations. L'interaction quasi élastique par courant chargé (CCQE) est le processus dominant pour T2K. Ce manuscrit décrit la mesure durapport des sections efficaces d'interaction des neutrinos sur les noyaux de Carbone et d'Oxygène. Cette mesure contribue à la réduction des incertitudes pour l'analyse d'oscillation, liéesà l'utilisation d'une différente cible pour le détecteur proche et le détecteur lointain. / The Standard Model of particle physics describes the interactions of subatomic particles through the strong, weak and electromagneticinteractions. However, it is known that this theory is not a complete description of the nature. Indeed the observation that neutrinos can change their flavor alongtheir propagation path (neutrino oscillation) proves that they actually have a mass. The work of this thesis has been performed in the T2K oscillation experiment: a long baseline experiment located in Japan. % detailed in Chapter ref{sec_t2k_res}.Using the data collected so far, T2K has been able to observe for the first time the $nu_{mu} rightarrow nu_e$ appearance and to give first results on the Charge-Paritysimmetry in neutrino oscillation. It provides also precise measurements of the oscillation parameters θ₁₃ , θ₂ ₃, Δm²₂ ₃.The precise measurement of oscillation parameters requires a good understanding of the detector and of the neutrino interaction model. This thesis is thus focused on boththese aspects: reduce the detector uncertainties and improve our knowledge of neutrino interactions with matter.The CEA Saclay group where I am involved, is in charge of the maintenance and operation of the Time Projection Chambers (TPCs) of the T2K near detector (ND280)which are used to identify and measure the kinematics of the charged particles produced in neutrino interactions.Part of my work was focused on the study of the TPC and in particular on the alignment of the MicroMegas modules instrumenting their readout planes.Indeed, misalignments between modules may cause a bias on the momentum measurement of the particles crossing the TPC.Neutrinos are studied through the observation of the final state of their interactions with matter. Therefore, the interactionmodels need to be extremely well understood to infer the neutrino properties correctly.Indeed current and next future oscillation experiments are approaching the phase of precise measurements of the mixing parameters becominglimited by our knowledge of neutrino interactions.The charged current quasi-elastic (CCQE) interaction is the most relevant process at T2K.This manuscript describes the measurement of CCQE cross-section ratio between oxygen and carbon nuclei. It can contribute to reduce the uncertainties on the oscillation analysis arisingfrom the different target between the near and far detector.