To calculate the load capacity of gear stages within complex drivetrains under varying external loads, multi-body-systems (MBS) are used to simulate the vibrational behaviour of integral systems. In order to model a flexible hypoid gear stage, methods like the modal reduction of FEM-models were already introduced. However, the modelling of such systems is complex, challenging and sensitive to its discretisation. The co-simulation within a multi-body-system simulation offers the possibility to outsource the calculation of the tooth contact and therefore the reaction forces under consideration of friction. This leads to a simplification and an improvement of the modelling of gear stages in multi-body-systems. The further developed co-simulation module offers a compromise between computational speeds and exact solutions. To improve the quality of the results and reduce the calculation time the load distribution calculation is investigated specifically. The article describes a method to reduce fluctuations of computed reaction forces and moments during gear movement. The aim is to keep the level of fluctuations of a high contact zone discretisation with a significant smaller contact point count. / Um die Belastbarkeit von Getriebestufen innerhalb komplexer Antriebsstränge unter variierenden äußeren Lasten zu berechnen, werden Mehrkörpersysteme (MKS) zur Simulation des Schwingungsverhaltens von integralen Systemen eingesetzt. Um eine flexible Getriebestufe mit Kegel- oder Hypoidradsätzen zu modellieren, wurden bereits Methoden wie die modale Reduktion von FEM-Modellen eingeführt. Die Modellierung solcher Systeme ist jedoch komplex, anspruchsvoll und empfindlich gegenüber ihrer Diskretisierung. Die Co-Simulation innerhalb einer Mehrkörpersystem-Simulation bietet die Möglichkeit, die Berechnung des Zahnkontakts und damit der Reaktionskräfte unter Berücksichtigung der Reibung auszulagern. Dies führt zu einer Vereinfachung und Verbesserung der Modellierung von Getriebestufen in Mehrkörpersystemen. Das weiterentwickelte Co-Simulations-Modul bietet einen Kompromiss zwischen Berechnungsgeschwindigkeit und exakten Lösungen. Um die Qualität der Ergebnisse zu verbessern und die Berechnungsgeschwindigkeit zu erhöhen, wurde die Berechnung der Lastverteilung untersucht. Der Artikel beschreibt eine Methode zur Reduzierung von Schwankungen der berechneten Kräfte und Momente über der Eingriffsstrecke. Ziel ist es, die Schwankungen auf dem Level einer hohen Kontaktzonendiskretisierung mit einer deutlich geringeren Kontaktpunktanzahl zu halten.

Physics / M. Sc. (Physics)

A two-dimensional integrodi erential equation resulting from the use of potential harmonics expansion in the many-body Schr odinger equation is used to study ground-state properties of selected few-body nuclear systems. The equation takes into account twobody correlations in the system and is applicable to few- and many-body systems. The formulation of the equation involves the use of the Jacobi coordinates to de ne relevant global coordinates as well as the elimination of center-of-mass dependence. The form of the equation does not depend on the size of the system. Therefore, only the interaction potential is required as input. Di erent nucleon-nucleon potentials and hyperon-nucleon potentials are employed to construct the Hamiltonian of the systems. The results obtained are in good agreement with those obtained using other methods. / Physics

No description available.

Este projeto está intimamente ligado à criação artística do ator, suas abordagens, reflexões e métodos. Ele está no âmbito da pesquisa do corpo cênico, de seus movimentos e de sua continua (re)significação perante quem o assiste e, por sua vez, da sua própria (re)organização. Para isso, cartografei meu próprio processo de aprendizagem e criação através dos diálogos entre o método de educação do movimento, Body Mind Centering®, inicialmente desenvolvido pela americana Bonnie Bainbridge Cohen, das formas de extração e codificação de matrizes corporais mapeadas por Renato Ferracini, e dos princípios da performance estudados por Renato Cohen. Assim, o desafio desta pesquisa foi a utilização do material perceptivo, proveniente da prática corporal, para a elaboração cênica. Ou seja, transcrever as sensações em matrizes codificadas, visando uma apresentação final em que este procedimento fosse (in)visível. / The present project is closely linked to the artistic creation of the actor, his approaches, thoughts and methods. The project is located in the realm of the research of the scenic body , its movements and its continuous (re)meaning in the face of the spectator and, on its turn, facing its own (re)organization. To achieve my goal I mapped our own learning and creation process through the dialog between the method of educating the movement, called Body Mind Centering ®, firstly developed by Bonnie Bainbridge, through the method of extracting and encoding the body matrixes mapped by Renato Ferracini, and through the performances studied by Renato Cohen. Therefore, the challenge of the present research was the use of perceptive material, deriving from the body practice used to build the scene. That means, translate the sensations into coded matrixes, aiming a final presentation where the said procedure would be (in)visible.

Este projeto está intimamente ligado à criação artística do ator, suas abordagens, reflexões e métodos. Ele está no âmbito da pesquisa do corpo cênico, de seus movimentos e de sua continua (re)significação perante quem o assiste e, por sua vez, da sua própria (re)organização. Para isso, cartografei meu próprio processo de aprendizagem e criação através dos diálogos entre o método de educação do movimento, Body Mind Centering®, inicialmente desenvolvido pela americana Bonnie Bainbridge Cohen, das formas de extração e codificação de matrizes corporais mapeadas por Renato Ferracini, e dos princípios da performance estudados por Renato Cohen. Assim, o desafio desta pesquisa foi a utilização do material perceptivo, proveniente da prática corporal, para a elaboração cênica. Ou seja, transcrever as sensações em matrizes codificadas, visando uma apresentação final em que este procedimento fosse (in)visível. / The present project is closely linked to the artistic creation of the actor, his approaches, thoughts and methods. The project is located in the realm of the research of the scenic body , its movements and its continuous (re)meaning in the face of the spectator and, on its turn, facing its own (re)organization. To achieve my goal I mapped our own learning and creation process through the dialog between the method of educating the movement, called Body Mind Centering ®, firstly developed by Bonnie Bainbridge, through the method of extracting and encoding the body matrixes mapped by Renato Ferracini, and through the performances studied by Renato Cohen. Therefore, the challenge of the present research was the use of perceptive material, deriving from the body practice used to build the scene. That means, translate the sensations into coded matrixes, aiming a final presentation where the said procedure would be (in)visible.

<p>Active vibration control to reduce vibrations and structure borne noise is considered using a powerful multi-disciplinary virtual design environment which enables control system design to be considered as an integral part of the overall vehicle design.</p><p>The main application studied is active automotive engine vibration isolation where, first, the potential of large frequency band multi-input multi-output H₂ feedback control is considered. Facilitated by the virtual environment, it is found necessary to take non-linear characteristics into account to achieve closed-loop stability.</p><p>A physical explanation to why receiver structure flexibility insignificantly affect the open and closed-loop characteristics in case of total force feedback in contrast to acceleration feedback is then given. In this context, the inherent differences between model order reduction by modal and by balanced truncation are being stressed.</p><p>Next, applying state-of-the-art algorithms for recursive parameter estimation, time-domain adaptive filtering is shown to lack sufficient tracking performance to deal with multiple spectral components of transient engine excitations corresponding to rapid car accelerations.</p><p>Finally, plant non-linearity as well as transient excitation are successfully handled using narrow band control based on feedback of disturbance states estimates. To deal with the non-linear characteristics, an approach to generate linear parameter varying descriptions of non-linear systems is proposed. Parameter dependent quadratic stability is assessed using a derived affine closed-loop system representation.</p><p>This thesis also considers actuator saturation induced limit cycles for observer-based state feedback control systems encountered when dealing with the active isolation application. It is stressed that the fundamental observer-based anti-windup technique could imply severely deteriorated closed-loop characteristics and even sustained oscillations. That is in the case when the observer is fed by the saturated control signal in contrast to the computed one. Based on piecewise affine system descriptions, analytical tools to conclude about limit cycles and exponential closed-loop stability are provided for the two observer implementations.</p>

Active vibration control to reduce vibrations and structure borne noise is considered using a powerful multi-disciplinary virtual design environment which enables control system design to be considered as an integral part of the overall vehicle design. The main application studied is active automotive engine vibration isolation where, first, the potential of large frequency band multi-input multi-output H2 feedback control is considered. Facilitated by the virtual environment, it is found necessary to take non-linear characteristics into account to achieve closed-loop stability. A physical explanation to why receiver structure flexibility insignificantly affect the open and closed-loop characteristics in case of total force feedback in contrast to acceleration feedback is then given. In this context, the inherent differences between model order reduction by modal and by balanced truncation are being stressed. Next, applying state-of-the-art algorithms for recursive parameter estimation, time-domain adaptive filtering is shown to lack sufficient tracking performance to deal with multiple spectral components of transient engine excitations corresponding to rapid car accelerations. Finally, plant non-linearity as well as transient excitation are successfully handled using narrow band control based on feedback of disturbance states estimates. To deal with the non-linear characteristics, an approach to generate linear parameter varying descriptions of non-linear systems is proposed. Parameter dependent quadratic stability is assessed using a derived affine closed-loop system representation. This thesis also considers actuator saturation induced limit cycles for observer-based state feedback control systems encountered when dealing with the active isolation application. It is stressed that the fundamental observer-based anti-windup technique could imply severely deteriorated closed-loop characteristics and even sustained oscillations. That is in the case when the observer is fed by the saturated control signal in contrast to the computed one. Based on piecewise affine system descriptions, analytical tools to conclude about limit cycles and exponential closed-loop stability are provided for the two observer implementations.

Ultra-cold atoms in optical lattices provide a versatile and robust platform to study fundamental condensed-matter physics problems and have applications in quantum optics as well as quantum information processing. For many of these applications, Rydberg atoms (atoms excited to large principal quantum numbers) are ideal due to its long coherence times and strong interactions. However, one of the pre-requisite for such applications is identical confinement of ground state atoms with Rydberg atoms. This is challenging for conventionally used alkali atoms. In this thesis, I discuss the potential of using alkaline-earth Rydberg atoms for many-body physics by implementing simultaneous trapping for the relevant internal states. In particular, I consider a scheme for generating multi-particle entanglement and explore charge transport in a one dimensional atomic lattice.

Cette thèse est consacrée à l'étude mathématique de deux systèmes quantiques décrits par des modèles non linéaires : le polaron anisotrope et les électrons d'un cristal périodique. Après avoir prouvé l'existence de minimiseurs, nous nous intéressons à la question de l'unicité pour chacun des deux modèles. Dans une première partie, nous montrons l'unicité du minimiseur et sa non-dégénérescence pour le polaron décrit par l'équation de Choquard--Pekar anisotrope, sous la condition que la matrice diélectrique du milieu est presque isotrope. Dans le cas d'une forte anisotropie, nous laissons la question de l'unicité en suspens mais caractérisons précisément les symétries pouvant être dégénérées. Dans une seconde partie, nous étudions les électrons d'un cristal dans le modèle de Thomas--Fermi--Dirac--Von~Weizsäcker périodique, en faisant varier le paramètre devant le terme de Dirac. Nous montrons l'unicité et la non-dégénérescence du minimiseur lorsque ce paramètre est suffisamment petit et mettons en évidence une brisure de symétrie lorsque celui-ci est grand. / This thesis is devoted to the mathematical study of two quantum systems described by nonlinear models: the anisotropic polaron and the electrons in a periodic crystal. We first prove the existence of minimizers, and then discuss the question of uniqueness for both problems. In the first part, we show the uniqueness and nondegeneracy of the minimizer for the polaron, described by the Choquard--Pekar anisotropic equation, assuming that the dielectric matrix of the medium is almost isotropic. In the strong anisotropic setting, we leave the question of uniqueness open but identify the symmetry that can possibly be degenerate. In the second part, we study the electrons of a crystal in the periodic Thomas--Fermi--Dirac--Von~Weizsäcker model, varying the parameter in front of the Dirac term. We show uniqueness and nondegeneracy of the minimizer when this parameter is small enough et prove the occurrence of symmetry breaking when it is large.