Cette thèse étudie les régions d'irrégularité marquée dans les spectres électroniques des dimères alcalins. Ces perturbations, qui rendent difficile voire impossible l’attribution habituelle et sans ambiguïté des nombres quantiques moléculaires, sont produites par de forts couplages spin-orbite. Des méthodes numériques nous permettent de résoudre l'équation de Schrödinger radiale pour de tels systèmes. Nous avons élaboré des stratégies permettant d’utiliser des formes analytiques pour les courbes d’énergie potentielle moléculaire et pour les fonctions de couplage spin-orbite. Nous prenons en compte les perturbations d’origine spin-orbite, et les effets de couplage spin-rotation dans des calculs d’états couplés, en utilisant des techniques numériques de différences finies et les méthodes de collocation, avec hamiltoniens moléculaires appropriés. La méthode a été testée avec succès sur des données publiées sur NaK, et également sur des données expérimentales obtenues pour des paires d’états électroniques excités fortement couplés (A 1Σ+(u) et b 3Π(u) pour Rb2 et pour NaCs), suite à des expériences de fluorescence induite par laser analysée par spectrométrie de Fourier. En optimisant les paramètres des potentiels moléculaires et des fonctions spin-orbite par le biais d’ajustements itératifs par moindres carrés non-linéaires, les modèles permettent d'atteindre la précision expérimentale (limite Doppler) actuelle. Les résultats sont controlés par étude des effets de substitution isotopique et des intensités observées. Un schéma pour refroidissement optique de NaCs a été proposé à partir des probabilités de transition calculées. / This thesis investigates regions of marked irregularity in the electronic spectra of alkali dimers. These perturbations, which make it difficult (if not impossible) to give the usual unambiguous assignment of molecular quantum numbers, are caused by strong spin-orbit coupling between close-lying electronic states. Numerical methods allow us to solve the radial Schrödinger equation for such systems. We have developed strategies to use analytical forms for molecular energy potentials and spin-orbit coupling functions in order to represent such situations, using Hund’s case (a) basis sets. Calculations are then performed using finite difference and collocation methods, with appropriate coupled-channel molecular Hamiltonians that take into account spin-orbit and spin-rotation interactions. Our analytical mapping procedure, based on a reduced variable representation of the radial coordinate, improves the computational efficiency for uniform finite-difference grid solutions of the coupled channel equations. The method has been successfully tested on published data for NaK (D 1Πd 3Πstates), and also on experimental data obtained by laser induced fluorescence and Fourier transform spectrometry for pairs of strongly coupled excited electronic states of heavier alkali species, Rb2 and NaCs (A 1Σ+(u) and b 3Π(u) states). Optimising the parameters of molecular potentials and spin-orbit functions through iterative non-linear least squares fits, the models achieve the current (Doppler limited) experimental level of precision. The validity of the results is confirmed by investigating the effects of isotopic substitution and intensity patterns. Results have been used to predict transition probabilities for a two-step optical cooling cycle for the NaCs molecule. / Данная диссертационная работа посвящена изучению возмущений в электронно-колебательно-вращательных спектрах димеров щелочных металлов. Нерегулярности вколебательно-вращательной структуре, вызванные сильным спин-орбитальнымвзаимодействием близко лежащих электронных состояний осложняют, а иногда и делаютневозможным, однозначное отнесение линий в молекулярных спектрах. В данной работе, врамках метода связанных колебательных каналов, разработана модель неадиабатическогоописания энергетических и радиационных свойств синглет-триплетных комплексоввозмущенных состояний, подчиняющихся промежуточным a-b-c случаям связи по Гунду взависимости от величины вращательного квантового числа и межъядерного расстояния.Ключевыми параметрами этой модели являются потенциальные кривые рассматриваемыхсостояний и функции спин-орбитального взаимодействия. Аналитическая замена радиальнойкоординаты в сочетании с аналитическим представлением варьируемых функций позволилиповысить эффективность решения системы уравнений Шредингера для рассматриваемыхсистем, а также улучшить экстраполяционные свойства неэмпирических функцийпотенциальной энергии. Предложенный подход использован для анализа (представленных влитературе) ровибронных энергий молекулы NaK (D1Π , d3Π состояния), а такжеоригинальных экспериментальных данных, полученных в данной работе методом лазерно-индуцированной флуоресценции для сильно возмущенных электронных состояний Rb2 иNaCs ( A1Σ(u)+ и b3Π(u) состояния). Проверка адекватности полученных структурныхпараметров выполнена путем предсказания и сопоставления с экспериментом (1)энергетических свойств для различных изотопомеров; (2) распределения относительныхинтенсивностей в спектрах лазерно-индуцированной флуоресценции с локальновозмущенных уровней комплексов в основное электронное состояние. Результаты,полученные для молекул NaCs, были использованы для расчета оптимальных путейдвухступенчатой оптической конверсии неустойчивых электронно-возбужденных молекул,образующихся в результате столкновений холодных атомов, на низший по энергиировибронный уровень основного электронного состояния.

On s’intéresse dans cette thèse à des systèmes couplés de type champ moyen en étudiant l’existence de l’état de synchronisation qui se caractérise par une distance uniformément bornée dans le temps entre chaque paire de composantes d’une solution. L’étude se base sur une méthode perturbative. Néanmoins les résultats obtenus ne sont pas évidents dans le cas non-perturbé. En outre dans le cas où le système couplé est périodique et grâce au Théorème du point fixe on montre l’existence d’une solution périodique sur le tore. L’étude de stabilité et de stabilité exponentielle est établie dans le cas linéaire et appliquée à ce type de systèmes couplés / We study in this thesis a class of a perturbed interconnected mean-field system, also known as a coupled systems. Under some assumptions we prove the existence of an invariant open set by the flow of the perturbed system ; in other word, we prove that the distance between the components of an orbit is uniformly bounded, this property is also called synchronization. We use the perturbation method to obtain the result. However the result is not trivial for the not perturbed system. We use the fixed point theorem to prove the existence of a periodic orbit in the torus. We study in addition the stability and the exponential stability of such systems by studying the stability of a linear systems.

Les sources d’énergies renouvelables représentent un gisement intéressant mais l’intermittence de leur production impose une meilleure anticipation des besoins et la mise en place d’un système de stockage d’énergie. Le stockage thermochimique par adsorption dans un système intégrant le couple zéolithe 13X/eau semble être une solution adaptée à un stockage de l’énergie à basse température pour une application aux bâtiments. Notre objectif consiste à reproduire le comportement de ce type de problèmes thermiques non-linéaires. En effet, une simulation précise et rapide du comportement du système sélectionné permettrait une régulation lors de son utilisation. Un modèle bidimensionnel de stockage d’énergie dans un adsorbeur cylindrique a été développé. La résolution numérique de ce modèle, dit d’ordre élevé, implique l’intégration d’un système de quelques centaines à quelques milliers d’équations fortement non-linéaires et couplés. Les coûts de calculs générés pouvant être prohibitifs, l’application d’une méthode de réduction a ainsi été envisagée afin de conserver les caractéristiques, le couplage des transferts de chaleur et de masse ainsi que les non-linéarités de ce modèle tout en limitant le temps de calculs. La projection de Galerkin des équations de ce dernier sur la base, obtenue grâce à une décomposition orthogonale aux valeurs propres, permet de construire un système dynamique d’ordre faible. Sa résolution est moins coûteuse que celle du modèle d’ordre élevé et reproduit correctement la dynamique de l’adsorbeur. / Renewable energy sources will play a key role in meeting future energy demand. One major criticism of those sources stands in their intermittency requiring both a more effective management of demand and efficient storage systems. We focus on thermo-chemical storage by adsorption-desorption mechanism. Eco friendly, economically viable and suitable with solar energy temperature range made the zeolite 13X - water pair ideal for buildings applications. We built an energy storage model in a cylindrical adsorber which contains the mentioned zeolite13X - water pair. Energy storage has been modeled to present coupled heat and mass transfers thanks to a bi-dimensional model. The numerical simulations lead to the time-space evolution of the heating fluid and adsorbent temperatures and pressure. These knowledge models include typically a great amount of coupled differential equations to solve and strong non linearities. The originality of this study is to build a knowledge model of coupled heat and mass transfer in an adsorber and use the Proper Orthogonal Decomposition (POD) and Galerkin projection to build a minimal model of lower dimension without significant loose of accuracy.

L’évolution actuelle des exigences en termes de performance énergétique des bâtiments a fait apparaître de nouveaux enjeux et problématiques scientifiques, dont ceux liés à l’humidité. Cette étude s’appuie sur une cellule expérimentale construite sur la technologie des maisons à ossature bois et soumise aux conditions climatiques réelles de Grenoble. L’instrumentation de ce bâtiment et le suivi de l’évolution en température et en humidité dans les différentes couches de l’enveloppe permettent de définir des séquences nécessaires à la validation de modèles numériques. Dans cet objectif, un modèle existant nommé HAM-Tools a été utilisé pour simuler les transferts couplés de chaleur, d’air et d’humidité à l’échelle du bâtiment. La démarche de validation a été décomposée en plusieurs étapes, de manière à cibler des transferts spécifiques et d’en améliorer la modélisation. Ces études localisées concernent les transferts couplés de chaleur et de masse à travers les parois solides, la modélisation des transferts de chaleur à travers une lame d’air ventilée et enfin la modélisation du renouvellement de l’air intérieur en conditions naturelles. Pour estimer la précision globale du modèle, c'est-à-dire à l’échelle du bâtiment, une séquence expérimentale a été simulée en prenant en compte l’ensemble des transferts couplés simultanément. Les performances du modèle sont discutées à partir des mesures locales, c'est-à-dire dans les parois, puis globales. La bonne concordance entre mesures et résultats de simulation permet de conclure sur la validité et la généricité de la démarche mise en œuvre et les hypothèses de simulation. Plus particulièrement, il est apparu que l’outil de modélisation permet de prédire correctement le comportement moyen des parois en humidité et en température. Il est donc envisageable de l’utiliser pour simuler et estimer l’impact des constituants des parois en termes de durabilité, de performances énergétiques et de confort de l’occupant. / As energy saving is so important in buildings nowadays, envelopes performances have to be more efficient and have to deal with more obligations, such as moisture accumulation and mould growth. This study relies on an experimental wooden frame house exposed to the natural conditions of Grenoble, France. It has been widely instrumented so the wall’s temperature and humidity is monitored at different depths. As a consequence, complete dataset are available and can be used to validate numerical model. In this work, an existing numerical model named HAM-Tolls has been used to simulate the heat, air and moisture coupled transfers at the building scale. The method developed here consists in validating the numerical model step by step, with studying specific transfers separately. The first step deals with heat and mass transfers across the walls. Then, the heat transfers across a ventilated air gap and the air change rate under natural conditions have been studied much in detail. The final step of this works consists in simulating simultaneously every transfer at the building scale. This latest simulation’s results were compared both on a local and on a global point of view with the measurements. As they were found to be in good agreement, this allows concluding on the methodology efficiency, the validity of the modelling assumption and gives good hope with extending this methodology to other studies. Specifically, the simulation tool is able to predict correctly the average temperature and humidity content within the walls. Therefore, it should be suitable with estimating the wall components influence on the wall durability, its energy efficiency and its impact on the occupant’s thermal comfort.

Cette thèse est composée de deux parties dans lesquelles nous étudions d'une part des estimations d'erreurs pour des schémas numériques associés à des équations de Hamilton-Jacobi du premier ordre. D'autre part, nous nous intéressons a l'étude de la stabilité et de la contrôlabilité exacte frontière indirecte des équations d'onde couplées.Dans un premier temps, en utilisant la technique de Crandall-Lions, nous établissons une estimation d'erreur d'un schéma numérique monotone aux différences finies pour des conditions de jonction dites a flux limité, pour une équation de Hamilton-Jacobi du premier ordre. Ensuite, nous montrons que ce schéma numérique peut être généralisé à des conditions de jonction générales. Nous établissons alors la convergence de la solution discrétisée vers la solution de viscosité du problème continu. Enfin, nous proposons une nouvelle approche, à la Crandall-Lions, pour améliorer les estimations d'erreur déjà obtenues, pour une classe des Hamiltoniens bien choisis. Cette approche repose sur l'interprétation du type contrôle optimal de l'équation de Hamilton-Jacobi considérée.Dans un second temps, nous étudions la stabilisation et la contrôlabilité exacte frontière indirecte d'un système monodimensionnel d’équations d'ondes couplées. D'abord, nous considérons le cas d'un couplage avec termes de vitesses, et par une méthode spectrale, nous montrons que le système est exactement contrôlable moyennant un seul contrôle à la frontière. Les résultats dépendent de la nature arithmétique du quotient des vitesses de propagation et de la nature algébrique du terme de couplage. De plus, ils sont optimaux. Ensuite, nous considérons le cas d'un couplage d'ordre zéro et nous établissons un taux polynômial optimal de la décroissance de l'énergie. Enfin, nous montrons que le système est exactement contrôlable moyennant un seul contrôle à la frontière / The aim of this work is mainly to study on the one hand a numerical approximation of a first order Hamilton-Jacobi equation posed on a junction. On the other hand, we are concerned with the stability and the exact indirect boundary controllability of coupled wave equations in a one-dimensional setting.Firstly, using the Crandall-Lions technique, we establish an error estimate of a finite difference scheme for flux-limited junction conditions, associated to a first order Hamilton-Jacobi equation. We prove afterwards that the scheme can generally be extended to general junction conditions. We prove then the convergence of the numerical solution towards the viscosity solution of the continuous problem. We adopt afterwards a new approach, using the Crandall-Lions technique, in order to improve the error estimates for the finite difference scheme already introduced, for a class of well chosen Hamiltonians. This approach relies on the optimal control interpretation of the Hamilton-Jacobi equation under consideration.Secondly, we study the stabilization and the indirect exact boundary controllability of a system of weakly coupled wave equations in a one-dimensional setting. First, we consider the case of coupling by terms of velocities, and by a spectral method, we show that the system is exactly controllable through one single boundary control. The results depend on the arithmetic property of the ratio of the propagating speeds and on the algebraic property of the coupling parameter. Furthermore, we consider the case of zero coupling parameter and we establish an optimal polynomial energy decay rate. Finally, we prove that the system is exactly controllable through one single boundary control

The structure of exotic nuclei is one of the main interests in current nuclear physics. Exotic nuclei present unusual properties, such as a low breakup energy, a short lifetime and/or a halo structure. Because of their short lifetimes, they can not be studied by usual spectroscopic techniques. Indeed, targets of such nuclei are impossible to build. But since the availability of radioactive beams, nuclear reactions have provided possibilities of exploring nuclei far from stability.<p><p>The investigation of exotic nuclei has been recently reactivated by the development of intense radioactive nuclear beams. As firstly observed for the deuteron, and then for other exotic projectiles such as $^6$He and $^{11}$Be, the internal structures of the interacting nuclei can have a significant effect on the elastic cross sections. Due to their low binding energy, the projectile dissociation process, leaving the target in its ground state, highly affects elastic cross sections but also other measurements such as transfer and fusion reactions. Accurate reaction theories are therefore needed. The coupled discretized-continuum channel (CDCC) method is one of those theories and assumes a projectile made of N clusters (usually N=2 or 3) impinging on a target which is structureless. The N+1-body Schrödinger equation is approximately solved by expanding the total wave function over the bound and continuum states of the projectile. These latter take into account the dissociation events and are approximately described by a truncated set of square-integrable wave functions. There are two available methods for discretizing the continuum, the pseudostate method where the projectile Hamiltonian is diagonalized within a finite basis of square-integrable functions, or the bin method where exact scattering wave functions of the projectile are averaged over bins in a finite region of space. In both cases, the N+1-body Schrödinger equation is replaced by a set of coupled-channel differential equations, which provides the physical quantities such as the collision matrix. In principle, the CDCC method can be very close to the exact N+1-body wave function and is adapted to low as well as to high energy reactions. However, its main interest consists in the low-energy domain.<p><p>In the present work, we propose a new approach to solve the CDCC equations. This method is based on the R-matrix theory associated with a Lagrange mesh basis. We will show that the combination of both approaches provides a fast and accurate technique to solve the CDCC equations, even for large systems, where traditional methods meet convergence problems. Before investigating collisions with exotic projectiles, we restrict ourselves to the simplest nucleus, the deuteron. Then we make a step towards a more complicated system, the $^6$Li which is a well known stable nucleus. We apply the CDCC method to the d + $^{58}$Ni and $^6$Li + $^{40}$Ca elastic scattering and breakup. These systems are considered in the literature as test cases. They have been investigated by several authors who showed the importance of the breakup channels in the elastic cross sections.<p><p>After having validated the present version of the CDCC method, we focus on $^{11}$Be, a typical example of a halo nucleus, with low binding energy and large quadrupole moment. Elastic, inelastic and breakup cross sections are computed in the CDCC formalism, at energies near the Coulomb barrier, where continuum effects in the scattering of exotic nuclei, and more specifically on the $^{11}$Be + $^{64}$Zn scattering, are observed. We show that converged cross sections need high angular momenta as well as large excitation energies in the wave functions of the projectile.<p><p>A Borromean nucleus is made of three constituents which are weakly linked together, but where each pair of those three constituents does not form a bound system. The name "Borromean" comes from the Borromean rings where, if any one of three rings is removed, the remaining two become unbound. Collisions with $^6$He and $^9$Be Borromean projectiles are studied in the present work. Again we compare our method with the $^6$He + $^{208}$Pb and $^6$He + $^{12}$C benchmark calculations. Afterwards, the convergence against the parameters of the description of the $^9$Be projectile is tested for the elastic cross section. The sensitivity to the technique employed to remove the forbidden states and also the sensitivity to the collision energy are investigated. / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

The overall objective is to improve the one-dimensional numerical prediction of the fine and non-cohesive bed material load in alluvial rivers, especially during high intensity episodes during which sediment beds are strongly remobilized. For this reason, we attempt to reduce the major inaccuracy sources coming from the alluvial resistance and bed material load relations needed to close the mathematical system. Through a shared parameter called the control factor m, the interactions occurring in alluvial rivers are incorporated more deeply into the mathematical model and more particularly into the closure laws: bed material load (SVRD, Suction-Vortex Resuspension Dynamics) and the energy slope (Verbanck et al. 2007). The control factor m is assumedly related to the Rossiter resonance modes of the separated flow downstream the bed form crest. <p><p>To further improve the representation of the flow-sediment-morphology interactions, a fully coupled model approach has been naturally chosen. In this work the terminology fully coupled means that the three equations forming the system are solved synchronously and that the terms often neglected by more traditional decoupled models are kept. <p><p>The feasibility of the new closure methodology has been drawn up by reproducing numerically the silt-flushing experiment conducted by the Yellow River Conservancy Commission (Y.R.C.C.) in the Lower Yellow River (LYR) in Northern China. The objective of the silt flushing experiment is to reverse the aggradation trend of the Lower Yellow River which, in the last decades, has become a perched river. The numerical simulation specifically reproduces the silt-flush effects in a reach of LYR located in the meandering part of the river. This reach (around 100 km) is delimited by Aishan and Luokou hydrometric stations.<p><p>Since the SVRD formulation has been developed from flume observations, the law has first been confronted to river datasets. The confrontation has revealed that the SVRD law becomes less suitable for fine sediment fluxes (ratio of water depth over median particle size > 5000). Therefore, a modified equation SVRD-2 has been built to enlarge the validity range.<p><p>The suitability of the SVRD-2 equation to predict fine sediment fluxes has been tested on data available from several hydrometric stations located in the meandering reach of the LYR: historical observations and measures collected during the flushes. The SVRD-2 has also been compared with relations specifically calibrated for this configuration. The comparison has pointed out that the performance of the two formulas is similar, which is encouraging for the SVRD-2 approach as it has not been calibrated on those data. <p><p>The closed equation system has been written on its quasi-linear form and is solved by a Finite Volume Method combined with a linearized Riemann algorithm. The numerical model has been checked up on two test cases: deposition upstream of a dam and the aggradation experiment conducted by Soni 1975. <p><p>As it is not yet possible to predict dynamically the value of the control factor m, a possible solution would be to extract its value from the measured data at the inlet cross section. Unfortunately, the necessary data are not measured locally. Moreover, a uniform value of the control factor m may not suffice to reproduce the flow along the whole reach. Therefore, it has been proposed to work temporarily in the reverse way. <p><p>From the comparison between the numerical results and the experimental data, a time evolution of the control factor m has effectively been extracted and it has been shown that it varies along the reach. At Aishan, the evolution of the control factor m corresponds to the evolution expected from the data analysis previously conducted on other data sets: the value of the control factor m decreases during the flush as it tries to reach the optimal value m=1. The time evolution at Luokou behaves differently to the one at Aishan, but remains in agreement with m evolution patterns observed historically for the river section flowing round Jinan City walls. For Luokou, the highlighted differences may come from three dimensional effects coming from the meander bend upstream the station.<p><p>Generally, the results obtained for the hydraulics, the sediment transport and bed adaptation are encouraging but still need improvements and additional feeding from the experimental data. The results for the concentration and therefore the bed elevation are very sensitive to the value of the control factor m as it influences most of the terms of the bed material load equation (SVRD-2). <p><p>The major remaining difficulties are, firstly, to deal with the rapid transients for which the model is less suitable and, secondly, to improve the prediction of the value of control factor m. Before paying more attention into the transients, enhancements concerning the flow along the reach (initial condition and discharge rates during the first days of the flush) must be conducted in priority. Indeed as the prediction of the bed or the cross section evolutions depend directly on the quality of the prediction of the sediment concentration and the hydraulics, one should first improve these aspects. To perform this study, more information about the water levels or sediment concentrations is necessary at some intermediate stations. One solution is to lengthen the studied reach, upstream to Sunkou and downstream to Lijin, totaling a river length of 456 Km.<p><p>A more entire signal of the energy slopes and the associated bed configurations at different stations would enlighten how the control factor m evolves along the reach during the silt-flush events. <p><p> / Doctorat en Sciences de l'ingénieur / info:eu-repo/semantics/nonPublished

Les récepteurs couplés aux protéines G constituent la plus grande famille de protéines membranaires et interviennent dans de nombreux processus physiologiques. La compréhension de l’interaction ligand-récepteur d’un point de vue mécanistique mais également thérapeutique est cruciale. Appartenant à la famille des récepteurs couplés aux protéines G, les récepteurs de la vasopressine et de l’ocytocine ont été choisis comme modèle d’étude. Ces hormones jouent un rôle important dans la modulation de l’attachement et de l’affect chez les mammifères. Afin d’accélérer la découverte de ligands ocytocinergiques et d’explorer les mécanismes fondamentaux de leurs interactions, nous avons conçu les premiers ligands fluorescents non peptidiques des récepteurs de la vasopressine V1a et de l’ocytocine. Ces ligands ont été utilisés pour développer des tests de liaisons par TR-FRET et démontrer la dimérisation des récepteurs de la vasopressine V1a et V2 sur cellules. Des études autour de petites plates-formes dérivées d’aza-dicétopipérazine ont permis d’accéder à un nouvel antagoniste non peptidique du récepteur de l’ocytocine. L’optimisation de dérivés benzodiazépines ocytocinergiques par des études de relations structure-activité a permis d’identifier les meilleurs agonistes non peptidiques du récepteur de l’ocytocine à ce jour. Une étude in vivo chez la souris et chez le singe est amorcée pour apporter dans un futur, une solution thérapeutique aux problèmes d’interaction sociale en général et d’autisme en particulier. / G protein coupled receptors are the largest membrane protein family and play an important role in a large number ofphysiological processes. The comprehension of the ligand-receptor interaction from a mechanistic point of view but alsofor therapeutic use is crucial. Belonging to the G protein coupled receptors, the oxytocin and vasopressin receptors havebeen used as a model system. These two hormones play an important role in the modulation of attachment and affectin mammals. To accelerate the discovery of new ligands for oxytocin and vasopressin receptors and to explore thefundamental role of their interactions, we designed the first non-peptide fluorescent ligands for oxytocin and vasopressin V1a receptors. These ligands have been used to develop new binding tests based on TR-FRET technology and to prove the V1a and V2 receptor dimerisation. In parallel, we developed a new non-peptide oxytocin antagonist around an aza-diketopiperazine platform. . Optimization of benzodiazepine derivatives enables us to identify the best non peptideoxytocin agonists to date. In vivo studies in mice and monkeys are initiated to bring in the future a therapeuticsolution to social interaction problems in general and autism in particular

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / This research is inserted in the Biomathematics Research Group of the Programa de Pós-Graduação em Matemática of the Universidade Federal de Santa Maria-RS. It consists in the study of a discrete model for a prey-predator-insecticide system based on the Coupled Map Lattice as basic tool for its formulation. Due to the serious problems that crop pests represent to agriculture, we aproached the Integrated Pest Management (IPM), which is a pest control system that seeks to preserve and enhance the natural mortality factors of pests by integrated use of control methods selected based on technical, economic, ecological and sociological parameters. The objective of this work is to build a model as simple as possible to study the effects of different pests management strategies. These strategies are divided into different treatments which take into account the number of measurements of pest population, establishing control levels (CL) and different control measures (pesticide and biological control). For comparison and to point where the treatment is more efficient to compute the total density of the pest population without any control measure and when each treatment is applied over a certain period of time. The difference between these values is converted into a decreasing percentage of the population of pests. The same is done to obtain the percentage decrease in the number of treated sites. It was found that the sooner you apply the insecticide in the system, the more effective the treatment. Furthermore, it was observed that the presence of predators (biological control) decreases the amount of treated sites and, in some instances, is less effective in controlling pest. / Esta pesquisa está inserida na Linha de Pesquisa Biomatemática, do Programa de Pós-Graduação em Matemática da Universidade Federal de Santa Maria-RS. Configura-se como um estudo sobre um modelo discreto para um sistema praga-predador-inseticida tendo como ferramenta básica para sua formulação a Rede de Mapas Acoplados. Devido aos sérios problemas que pragas de lavoura representam para agricultura, abordou-se o Manejo Integrado de Pragas (MIP), que é um sistema de controle de pragas que busca preservar e aumentar os fatores de mortalidade natural de pragas pelo uso integrado de métodos de controle selecionados com base em parâmetros técnicos, econômicos, ecológicos e sociológicos. O objetivo deste trabalho é construir um modelo tão simples quanto possível, para estudar as consequências de diferentes estratégias de manejos de pragas. Essas estratégias são divididas em tratamentos diferentes nos quais leva-se em consideração o número de medições da população de pragas, estabelecimento de níveis de controle (NC) e diferentes medidas de controle aplicadas (inseticida e controle biológico). Para comparar e apontar qual dos tratamentos é mais eficiente, computou-se a densidade total da população de pragas sem nenhuma medida de controle e quando cada um dos tratamentos é aplicado ao longo de um determinado período de tempo. A diferença entre esses valores é convertida em um percentual de decrescimento da população de pragas. O mesmo é feito para se obter o percentual de decrescimento do número de sítios tratados. Foi possível constatar que quanto mais cedo se aplica o inseticida no sistema, mais efetivo é o tratamento. Além disso, observou-se que a presença dos predadores (controle biológico) diminui a quantidade de sítios tratados e, em alguns momentos, é menos eficiente no controle da praga.

Cette thèse traite des convertisseurs multiniveaux destinés aux applications moteurs rapides, utilisés notamment dans le domaine de l'Oil \& Gas. L'objectif est l'étude d'une structure qui permette de réduire les pertes par commutation, en comparaison avec la topologie conventionnelle NPC (Neutral Point Clamped) 3 niveaux, actuellement utilisée. De plus, la structure de convertisseur doit permettre de fournir des grandeurs d'entrée au moteur ayant un faible taux de distorsion harmonique, de manière à ne pas créer des échauffements supplémentaires dans le moteur.Après avoir effectué une étude des différentes structures existantes, la structure NPP (Neutral Point Piloted) 3 niveaux est finalement retenue au vu de ses différentes qualités. En effet, grâce à la mise en série de composants semi-conducteurs, les pertes par commutation de ces derniers sont divisées par deux par rapport aux composants homologues de la topologie NPC. Après avoir comparé les topologies NPC et NPP en termes de forme d'onde et de répartition des pertes dans les composants, l'auteur s'intéresse à la validation expérimentale de cette structure. Les performances atteintes par le convertisseur NPP sont intéressantes puisqu'elles permettent de commuter à des fréquences deux fois plus élevées que la topologie NPC pour un courant donné ou de commuter un courant plus important pour une fréquence de commutation donnée.Les schémas de commutation des différents composants du bras NPP sont étudiés afin de comprendre le gain non négligeable obtenu sur cette structure.Malgré le fait que la structure NPP permette de commuter à des fréquences deux fois plus élevées que la structure NPC, on ne peut pas s'affranchir du filtre sinus en sortie de l'onduleur de manière à respecter les contraintes harmoniques au niveau du moteur. Ainsi, une topologie de filtre sinus à inductances couplées a été introduite / This PhD thesis deals with multilevel inverters dedicated to high speed motors applications, used in Oil \& Gas applications. The main objective is to study a topology which enables reducing switching losses, in comparison with the conventional 3-level NPC (Neutral Point Clamped) topology. Moreover, the inverter has to provide motor input signals with a low harmonic distortion level, not to create undesired additional heating in the motor. After a study of the existing topologies, the 3-level NPP (Neutral Point Piloted) topology is chosen regarding all its benefits. Indeed, thanks to series connection of semi-conductor components, switching losses can be divided by two compared to homologous components on the NPC topology. After having compared NPC and NPP topologies in terms of waveforms and losses distribution in components, the author interest is the experimental validation of this topology. The performances reached by the NPP inverter are interesting because it enables to switch two times faster than for a NPC topology for a given current or to switch a higher current for a given switching frequency. The switching schemes of the NPP leg are studied to understand the gain obtained on this topology. In spite of the fact that switching frequency can be doubled on the NPP topology, the sinus filter can not be avoided in order to respect harmonic specification on the motor. A sinus filter with coupled inductances is introduced so that to responds the different sizing criteria