Alors qu’il existe de nombreux calculs microscopiques de barrières de fission pour des noyaux composés pair-pairs, il n’y a cependant que relativement peu de tels calculs pour des noyaux de masse impaire. Ceci est dû aux complications induites par la brisure de la symétric de reversement du sens du temps au niveau du champ moyen qui est engendrée par la présence d’un nucleon non apparié. Pour éviter cette difficulté, des calculs existants pour des noyaux de masse impaire ont tout simplement négligé ces effets de brisure de la symétrie de reversement du sens du temps.Dans ce travail, on se donne pour but d’améliorer la description des barrières de fission, aussi bien que des propriétés spectroscopiques du niveau fondamental et de l’état isomérique de fission,pour quelques isotopes de masse impaire dans la région des actinides en prenant en compte de tels effets. Ceci a été réalisé dans le cadre du formalisme de Skyrme–Hartree–Fock plus BCS avec blocking en adaptant ce formalisme à la brisure de la symétrie considérée. L’interaction résiduelle d’appariement a été approchée par une force de séniorité dont les paramètres ont été ajustés pour reproduire les différences de masse pair-impair de quelques noyaux de la région des actinides.Les énergies des têtes de bande rotationnelle de basse énergie ont été calculées dans le cadre du modèle unifié de Bohr-Mottelson pour quatre noyaux bien déformés (235U, 239Pu, 237Np, 241Am)produisant un bon accord qualitatif avec les données pour les noyaux impairs en neutrons. L’accord significativement moins bon obtenu pour les noyaux impairs en protons pourrait résulter de l’usage de l’approximation de Slater pour l’interaction d’échange de Coulomb. Les énergies de déformation de deux noyaux impairs en neutrons (235U, 239Pu) ont été calculées pour quelques configurations de particule individuelle, jusqu’après la barrières de fission externe. La symétrie axiale a été imposée tandis que la brisure de la symétrie droite-gauche (ou de parité intrinsèque) a été permise dans la région de la seconde barrière. Les hauteurs des barrières de fission pour ces noyaux impairs dépendent significativement des configurations de particule individuelle. Un accord qualitatif avec les données disponibles pour les hauteurs de barrières des noyaux impairs considérés et leurs voisins pair-pairs a été généralement obtenu. / While there have been numerous microscopic calculations on fission barriers of even-even compoundnuclei, there are however, relatively few such work dedicated to odd-mass nuclei. This is dueto the complications posed by the breaking of the time-reversal symmetry at the mean-field leveldue to the presence of an unpaired nucleon. In order to circumvent this difficulty, previous fission barriercalculations of odd-mass nuclei have been performed by neglecting the effect of time-reversalsymmetry breaking. This work aims to improve on the description of fission barriers as well asthe spectroscopic properties of ground and fission-isomeric state, of some odd-mass actinide nucleiby taking the effect of time-reversal symmetry breaking into account. This has been perfomedwithin a Skyrme-Hartree-Fock-plus-BCS framework with blocking, where the BCS formalism hasbeen adapted to accomodate this symmetry breaking. The Skyrme nucleon-nucleon effective forcehas been used with various sets of parameters (SIII, SkM*, SLy5*). The residual pairing interactionhas been approximated by seniority forces whose neutron and proton parameters have beenfitted to reproduce the odd-even mass differences of some actinide nuclei. The low-lying rotationalband-head energies evaluated within the Bohr-Mottelson unified model have been determined forfour well-deformed odd-nuclei (235U, 239Pu, 237Np, 241Am) yielding a good qualitative agreementto the data for odd-neutron nuclei. The agreement was significantly less good for the odd-protonnuclei, possibly due to the use of the Slater approximation for the exchange Coulomb interaction.The deformation energies of two odd-neutron nuclei (235U and 239Pu) have been calculated forsome single-particle configurations up to a point beyond the outer fission-barrier. Axial symmetrynuclear shape has been assumed while a breaking of the left-right (or intrinsic parity) symmetryhas been allowed around the outer fission-barrier. The fission-barrier heights of such odd-neutronnuclei depend significantly on the particle configurations. A special attention has been paid tothe very important rotational correction to deformation energies. In particular, the correction ofthe moment of inertia calculated from the usual Belyaev expression was considered. Overall, aqualitative agreement with available data on fission-barrier heights for the considered odd-neutronnuclei and their even neighbours has been obtained.

Les erreurs récurrentes et systématiques dans les processus de décision stratégique sont fréquentes ; et les théories actuelles des organisations sont insuffisantes pour les expliquer. La « Behavioral Strategy » suggère de lier ces erreurs à la psychologie des décideurs, et notamment à leurs biais cognitifs. Toutefois, cette vision suppose de connecter le niveau d’analyse de l’individu et celui de l’organisation. Nous proposons pour ce faire un niveau « méso », la routine de choix stratégique (RCS), où interagissent la psychologie des décideurs et les décisions stratégiques. Après avoir distingué trois types de RCS, nous formulons des hypothèses d’intervention sur celles-ci visant à prévenir les erreurs stratégiques. Nous illustrons ces hypothèses par six cas pratiques, en testons certaines par une étude quantitative, et analysons les préférences qui conduisent les dirigeants à les adopter ou non. Nous concluons en discutant les implications théoriques et pratiques de notre démarche. / Many types of strategic decisions result in recurring, systematic errors. Extant theories of organizations are insufficient to account for this phenomenon. Behavioral Strategy suggests that an explanation may be found in the psychology of decision makers, and particularly in their cognitive biases. This, however, calls for a link between individual-level cognition and affects, and organization-level choices. We propose “Strategic Choice Routines” as a middle level of analysis to bridge this gap, and identify three broad types of Strategic Choice Routines.This leads us to formulate hypotheses on how Strategic Choice Routines can be modified to minimize strategic errors. We illustrate these hypotheses through case studies; test some of them quantitatively; and analyze preferences that drive their adoption by executives. Finally, we discuss theoretical and managerial implications.

Particle suspensions occur in many situations in nature and industry. In this master’s thesis, the motion of a single rigid spheroidal particle immersed in Stokes flow is studied numerically using a boundary integral method and a new specialized quadrature method known as quadrature by expansion (QBX). This method allows the spheroid to be massless or inertial, and placed in any kind of underlying Stokesian flow.   A parameter study of the QBX method is presented, together with validation cases for spheroids in linear shear flow and quadratic flow. The QBX method is able to compute the force and torque on the spheroid as well as the resulting rigid body motion with small errors in a short time, typically less than one second per time step on a regular desktop computer. Novel results are presented for the motion of an inertial spheroid in quadratic flow, where in contrast to linear shear flow the shear rate is not constant. It is found that particle inertia induces a translational drift towards regions in the fluid with higher shear rate. / Partikelsuspensioner förekommer i många sammanhang i naturen och industrin. I denna masteruppsats studeras rörelsen hos en enstaka stel sfäroidisk partikel i Stokesflöde numeriskt med hjälp av en randintegralmetod och en ny specialiserad kvadraturmetod som kallas quadrature by expansion (QBX). Metoden fungerar för masslösa eller tröga sfäroider, som kan placeras i ett godtyckligt underliggande Stokesflöde.   En parameterstudie av QBX-metoden presenteras, tillsammans med valideringsfall för sfäroider i linjärt skjuvflöde och kvadratiskt flöde. QBX-metoden kan beräkna kraften och momentet på sfäroiden samt den resulterande stelkroppsrörelsen med små fel på kort tid, typiskt mindre än en sekund per tidssteg på en vanlig persondator. Nya resultat presenteras för rörelsen hos en trög sfäroid i kvadratiskt flöde, där skjuvningen till skillnad från linjärt skjuvflöde inte är konstant. Det visar sig att partikeltröghet medför en drift i sidled mot områden i fluiden med högre skjuvning.

This MSc Thesis focuses on the collision detection between scene objects and consequent resolution of such collisions on the basis of physical model. The implementation of all the applications and algorithms is achieved in Win32 environment in Visual Studio using the programming language C++; it also employs the graphical library Open Inventor based on OpenGL. The work also includes additional application for the calculation of physical values. The demo applications involve algorithms for detection and resolution of explosive collision by the use of a simple and physical reflection on the basis of physical formulas and relationships. The main demo application called "tunnel transit" incorporates a simple game engine. The thesis also includes a discussion over the aroused problems with collision solving and some suggestions how to overcome them.

This thesis presents a novel analytical solution strategy for the zero-inertia (ZI) equations of free surface flow. These equations are utilized herein for routing flood flow in open channels and for simulating excess rainfall runoff on overland planes. The novel solution approach is shown to be both accurate and robust, especially under the complicated and intricate conditions of infiltrating flow on initially dry river beds or soils, e.g., as present in arid and semiarid areas. This is underlain by comparing modeling results of the novel analytical procedure with those of validated numerical solutions. Furthermore, it is shown that the analytical ZI model can deliver a process-oriented portrayal of runoff concentration in the flood-generating parts of the catchment. Subsequently, the novel analytical ZI model is applied for a real-world water management problem in the Sultanate of Oman, Arabian Peninsula. Within an integrated flash flood routing model—which is also presented in this thesis—the novel analytical routing approach helps in accurately matching the dynamics of advancing and infiltrating ephemeral river flow, established as a consequence of release from a groundwater recharge dam. The integrated modeling system houses the aforementioned analytical downstream model and tailor-made, state-of-the-art modeling components to portray the upstream flow processes, dam operation (including evaporation), and spillway release flow. The proposed modeling system can aid in rendering a realistic image of transient transmission losses and dependent flow dynamics. This is of extremely high importance for water resources assessment, as well as for optimizing recharge dam operation strategies in order to maximize downstream transmission losses and, thus, groundwater recharge.:List of Figures List of Tables List of Algorithms List of Symbols and Acronyms 1 Introduction 1.1 The Role of Ephemeral River Flow for Groundwater Recharge 1.2 Methods for Estimating Groundwater Recharge 1.3 Groundwater Augmentation Techniques and the Involved Processes 1.4 The Role of Overland Flow for Flash Flood Formation 1.5 Objectives of the Thesis 1.6 Structure of the Work 2 Literature Review 2.1 Surface-Water Based Studies on the Estimation of Indirect Recharge 2.2 Review of Literature on Process-Oriented Overland Flow Modeling 2.3 Summary 3 Principles of Physically-Based Modeling of Infiltrating Free Surface Flows 3.1 Hydraulic Phases of an Infiltrating Flow Event 3.2 Hydrodynamic Models 3.2.1 The Saint-Venant Equations 3.2.2 Zero-Inertia Approximation 3.2.3 Kinematic Wave Approximation 3.2.4 Other Simplifications of the Full Hydrodynamic Model 3.3 Initial and Boundary Conditions 3.4 Relating Friction and Flow Properties 3.5 Accounting for Losses or Gains 3.6 Including Arbitrary Cross-Sectional Geometries 3.7 Discussion of the Reviewed Flow Models 3.7.1 Discussion of Modeling Approaches for Ephemeral River Routing 3.7.2 A Suitable Hydrodynamic Model for Overland Flow 3.7.3 On the Portrayal of Shocks with the Kinematic Wave Model 3.8 Summary 4 Solution Procedures for the Reviewed Flow Models 4.1 Method of Characteristics 4.2 Numerical Solution Procedures 4.2.1 Introduction to Finite Difference Methods 4.2.2 Mathematical Principles of Finite Difference Methods 4.3 Analytical Solution Procedures 4.4 Discussion of the Reviewed Solution Procedures 4.5 Summary and Conclusions 5 Novel Analytical Solution Approaches for the Zero-Inertia Equations 5.1 Novel Analytical Solution Approach for Zero-Inertia Open Channel Flow 5.1.1 Governing Equations 5.1.2 Including Nonprismatic Channel Geometries 5.1.3 Boundary and Initial Conditions 5.1.4 Analytical Solution of the Momentum Equation 5.1.5 Analytical Solution of the Continuity Equation 5.1.6 Algorithm for the Iterative Solution of the Nonlinear Problem 5.1.7 Coupling Surface Flow and Infiltration 5.1.8 Additional Remarks 5.2 Novel Analytical Solution Approach for Zero-Inertia Overland Flow 5.2.1 Governing Equations 5.2.2 Boundary and Initial Conditions 5.2.3 Analytical Solution 5.2.4 Algorithm for the Iterative Solution of the Nonlinear Problem 5.3 Summary 6 Comparative Studies with Generally Accepted Approaches 6.1 Open Channel Flow in Prismatic and Nonprismatic Permeable Open Channels 6.1.1 Test Setup 6.1.2 Comparison of Flow Dynamics 6.1.3 Analysis of the Geometry Parameter Sensitivity 6.1.4 Evaluating the Stability of the Analytical ZI Model 6.1.5 Summary 6.2 Overland Flow on a Plane 6.2.1 Test Setup 6.2.2 Comparison of Modeling Results 6.2.3 Summary 7 Flash Flood Routing under Transmission Losses and Dam Operation 7.1 Outline of the Structure of a Novel Integrated Modeling System 7.1.1 Wadi Flow Routing Models 7.1.2 Dam Simulation Model with Evaporation Component 7.2 Real-World Application of the Modeling System for an Arid Region 7.2.1 Study Area and Available Data 7.2.2 Parameter Sensitivity Analysis 7.2.3 Optimization-Based Process Parameter Estimation 7.2.4 Model Application for Wadi Ma\\\\\\\'awil 7.3 Summary 8 Summary and Conclusions 9 Outlook 9.1 The Modeling System for Improving Water Resources Assessment 9.2 The Modeling System for Optimizing Groundwater Recharge Bibliography A Mathematical Supplements A.1 Explicit First-Order Finite Difference Scheme for the Kinematic Wave Model A.2 Explicit Second-Order Finite Difference Scheme for the Kinematic Wave Model A.3 Implicit Finite Difference Scheme with Interior Point (Preissmann Scheme) A.4 Analytical Solution of the Kinematic Wave Model A.5 Details on the Derivation of the Iterative Procedure (5.47);(5.48) A.6 Details on the Evaluation of Equation (5.60) B Selected Publications of the Author B.1 Analytical Model of Surge Flow in Nonprismatic Permeable Channels B.2 Analytical Model of Surface Flow on Hillslopes B.3 Integrated Modeling System for Flash Flood Routing in Ephemeral Rivers / Diese Dissertation präsentiert einen neuartigen analytischen Lösungsansatz für das beschleunigungsfreie Wellenmodell (bzw. „Zero-Inertia-Modell“, „ZI-Modell“, oder „diffusives Wellenmodell“). Im Rahmen der Arbeit wird das hergeleitete hydrodynamische Modell sowohl zur Simulation von Freispiegelabflüssen in nichtprismatischen und durchlässigen Gerinnen, als auch für die Beschreibung von auf der Landoberfläche abfließendem Infiltrationsüberschuss eingesetzt. Es wird gezeigt, dass der neuartige analytische Ansatz — im Hinblick auf Massenerhaltung und die exakte Abbildung der Abflussdynamik — akkurate Ergebnisse liefert und gleichzeitig unter komplexen und verwickelten Prozessbedingungen anwendbar ist. So belegt eine vergleichende Analyse mit validierten numerischen Lösungsansätzen die Robustheit des analytischen ZI-Modells. Insbesondere die im Sinne der numerischen Mathematik stabile und genaue Modellierung der gekoppelten Abfluss- und Infiltrationsvorgänge in anfänglich trockenen Gerinnen ist dabei ein Novum. Weiterhin wird die Eignung und Anwendbarkeit des neuartigen Modellansatzes zur Beschreibung der Abflusskonzentrationsprozesse gezeigt. Der neuartige Lösungsansatz wird im Folgenden für ein reales Wassermanagementproblem im Sultanat Oman, Arabische Halbinsel eingesetzt. Als Bestandteil eines integrierten Modellsystems, welches ebenfalls im Rahmen der Dissertation vorgestellt wird, dient das analytische ZI-Modell zur Simulation von infiltrierendem Wadiabfluss, welcher unterstrom von Grundwasseranreicherungsdämmen starke Verluste von Masse und Impuls erfährt. Zusammen mit maßgeschneiderten und dem Stand der Technik entsprechenden Komponenten für die Betriebssimulation des Anreicherungsdammes (inklusive Verdunstung von der freien Seefläche) sowie für die Abbildung der oberstromigen hydrodynamischen Prozesse (ebenfalls inklusive Infiltration) wird der neuartige analytische Ansatz in einem Modellsystem zusammengefasst. Das Modellsystem ist in der Lage ein realistisches Bild der raumzeitlichen Dynamik des Abflusses sowie der Grundwasserneubildung aus infiltrierendem Wadiabfluss zu liefern. Damit stellt das Modellsystem ein wertvolles Werkzeug sowohl zur Wasserdargebotsermittlung, als auch für die Optimierung des Betriebes von Grundwasseranreicherungsdämmen dar.:List of Figures List of Tables List of Algorithms List of Symbols and Acronyms 1 Introduction 1.1 The Role of Ephemeral River Flow for Groundwater Recharge 1.2 Methods for Estimating Groundwater Recharge 1.3 Groundwater Augmentation Techniques and the Involved Processes 1.4 The Role of Overland Flow for Flash Flood Formation 1.5 Objectives of the Thesis 1.6 Structure of the Work 2 Literature Review 2.1 Surface-Water Based Studies on the Estimation of Indirect Recharge 2.2 Review of Literature on Process-Oriented Overland Flow Modeling 2.3 Summary 3 Principles of Physically-Based Modeling of Infiltrating Free Surface Flows 3.1 Hydraulic Phases of an Infiltrating Flow Event 3.2 Hydrodynamic Models 3.2.1 The Saint-Venant Equations 3.2.2 Zero-Inertia Approximation 3.2.3 Kinematic Wave Approximation 3.2.4 Other Simplifications of the Full Hydrodynamic Model 3.3 Initial and Boundary Conditions 3.4 Relating Friction and Flow Properties 3.5 Accounting for Losses or Gains 3.6 Including Arbitrary Cross-Sectional Geometries 3.7 Discussion of the Reviewed Flow Models 3.7.1 Discussion of Modeling Approaches for Ephemeral River Routing 3.7.2 A Suitable Hydrodynamic Model for Overland Flow 3.7.3 On the Portrayal of Shocks with the Kinematic Wave Model 3.8 Summary 4 Solution Procedures for the Reviewed Flow Models 4.1 Method of Characteristics 4.2 Numerical Solution Procedures 4.2.1 Introduction to Finite Difference Methods 4.2.2 Mathematical Principles of Finite Difference Methods 4.3 Analytical Solution Procedures 4.4 Discussion of the Reviewed Solution Procedures 4.5 Summary and Conclusions 5 Novel Analytical Solution Approaches for the Zero-Inertia Equations 5.1 Novel Analytical Solution Approach for Zero-Inertia Open Channel Flow 5.1.1 Governing Equations 5.1.2 Including Nonprismatic Channel Geometries 5.1.3 Boundary and Initial Conditions 5.1.4 Analytical Solution of the Momentum Equation 5.1.5 Analytical Solution of the Continuity Equation 5.1.6 Algorithm for the Iterative Solution of the Nonlinear Problem 5.1.7 Coupling Surface Flow and Infiltration 5.1.8 Additional Remarks 5.2 Novel Analytical Solution Approach for Zero-Inertia Overland Flow 5.2.1 Governing Equations 5.2.2 Boundary and Initial Conditions 5.2.3 Analytical Solution 5.2.4 Algorithm for the Iterative Solution of the Nonlinear Problem 5.3 Summary 6 Comparative Studies with Generally Accepted Approaches 6.1 Open Channel Flow in Prismatic and Nonprismatic Permeable Open Channels 6.1.1 Test Setup 6.1.2 Comparison of Flow Dynamics 6.1.3 Analysis of the Geometry Parameter Sensitivity 6.1.4 Evaluating the Stability of the Analytical ZI Model 6.1.5 Summary 6.2 Overland Flow on a Plane 6.2.1 Test Setup 6.2.2 Comparison of Modeling Results 6.2.3 Summary 7 Flash Flood Routing under Transmission Losses and Dam Operation 7.1 Outline of the Structure of a Novel Integrated Modeling System 7.1.1 Wadi Flow Routing Models 7.1.2 Dam Simulation Model with Evaporation Component 7.2 Real-World Application of the Modeling System for an Arid Region 7.2.1 Study Area and Available Data 7.2.2 Parameter Sensitivity Analysis 7.2.3 Optimization-Based Process Parameter Estimation 7.2.4 Model Application for Wadi Ma\\\\\\\'awil 7.3 Summary 8 Summary and Conclusions 9 Outlook 9.1 The Modeling System for Improving Water Resources Assessment 9.2 The Modeling System for Optimizing Groundwater Recharge Bibliography A Mathematical Supplements A.1 Explicit First-Order Finite Difference Scheme for the Kinematic Wave Model A.2 Explicit Second-Order Finite Difference Scheme for the Kinematic Wave Model A.3 Implicit Finite Difference Scheme with Interior Point (Preissmann Scheme) A.4 Analytical Solution of the Kinematic Wave Model A.5 Details on the Derivation of the Iterative Procedure (5.47);(5.48) A.6 Details on the Evaluation of Equation (5.60) B Selected Publications of the Author B.1 Analytical Model of Surge Flow in Nonprismatic Permeable Channels B.2 Analytical Model of Surface Flow on Hillslopes B.3 Integrated Modeling System for Flash Flood Routing in Ephemeral Rivers

The new EU omnibus directive mandates that companies must now show the lowest previous price of a product. In a behavioral experiment, we investigate whether this affects consumers’ willingness to buy. We also test for gender differences in consumers’ willingness to buy when being exposed to the lowest previous price. Today gender-stereotypical norms like Girl math are present on social media. Hence, it is highly relevant to understand if these gender differences in consumer behavior exist and why. In the experiment, we also observe whether the effect of previous lowest price differ depending whether the good in question is hedonic or utilitarian and on the consumer’s level of information ignorance. The experiment was conducted online, where participants made a series of purchasing decisions. The participants were assigned to be either in a control or a treatment group, where the treatment group was exposed to the lowest previous price. Results from t-tests and OLS regressions indicate a negative effect on willingness to buy when consumers are exposed to the lowest previous price, with no difference between men and women. However, general willingness to buy in the experiment differed between genders regardless of the lowest previous price, suggesting that differences in shopping behavior are mainly due to varying attitudes towards purchasing decisions. Hedonic goods are less affected by the lowest previous price compared to utilitarian goods and the effect on willingness to buy when exposed to the lowest previous price is decreasing with increasing financial ignorance, which may be due to individuals ignoring information rather than being affected by decision inertia. / Den skärpa Prisinformationslagen innebär att företag nu måste ange tidigare lägsta pris på en vara. I ett beteendeexperiment undersöker vi om detta påverkar konsumenters köpbenägenhet. Vi testar även om det finns könsskillnader i köpbenägenhet vid exponering av tidigare lägsta pris. Idag finns det könsstereotypiska normer som växer fram på sociala medier, därför är det ytterst relevant att förstå om dessa könsskillnader i köpbeteenden finns och varför. I experimentet observerar vi även om effekten av tidigare lägsta pris på köpbenägenhet skiljer sig åt beroende på om varan i fråga är för nytta eller nöjes skull samt konsumentens nivå av informationsignorans. Experimentet genomfördes online där deltagarna skulle göra en rad av köpbeslut. Deltagarna blev antingen indelade i en kontroll- eller behandlingsgrupp, där deltagarna i behandlingsgruppen blev exponerade för tidigare lägsta pris. Resultaten från t-tester och OLS-regressioner indikerar på att det finns en negativ effekt på köpbenägenheten när en konsument exponeras för tidigare lägsta pris. Denna effekt skiljer sig inte mellan män och kvinnor. Däremot skiljer sig den allmänna köpbenägenheten i experimentet mellan män och kvinnor, oberoende av tidigare lägsta pris, vilket tyder på att skillnaderna i köpbeteende huvudsakligen beror på olika attityder vid shopping och köpbeslut. Hedoniska varor påverkas mindre än utilitariska varor av tidigare lägsta pris, samtidigt som ökad finansiell ignorans leder till en lägre påverkan på köpbenägenhet vid exponering av tidigare lägsta pris vilket kan kopplas till att individer ignorerar information snarare än drabbas av beslutströghet.

This report travels through multiple disciplines to seek innovative and sustainable energy solutions for wastewater treatment plants. The first subject is a report about increased global temperatures and an over-exploitation of natural resources that threatens ecosystems worldwide. The situation is urgent where the current trend is a 2°C increase of global temperatures already in 2040. Furthermore, the energy-land nexus becomes increasingly apparent where the world is going from a dependence on easily accessible fossil resources to renewables limited by land allocation. A direction of the required transition is suggested where all actors of the society must contribute to quickly construct a new carbon-neutral resource and energy system. Wastewater treatment is as required today as it is in the future, but it may move towards a more emphasized role where resource management and energy recovery will be increasingly important. This report is a master’s thesis in energy engineering with an ambition to provide some clues, with a focus on energy, to how wastewater treatment plants can be successfully integrated within the future society. A background check is conducted in the cross section between science, society, politics and wastewater treatment. Above this, a layer of technological insights is applied, from where accessible energy pathways can be identified and evaluated. A not so distant step for wastewater treatment plants would be to absorb surplus renewable electricity and store it in chemical storage mediums, since biogas is already commonly produced and many times also refined to vehicle fuel. Such extra steps could be excellent ways of improving the integration of wastewater treatment plants into the society. New and innovative electric grid-connected energy storage technologies are required when large synchronous electric generators are being replaced by ‘smaller’ wind turbines and solar cells which are intermittent (variable) by nature. A transition of the society requires energy storages, balancing of electric grids, waste-resource utilization, energy efficiency measures etcetera… This interdisciplinary approach aims to identify relevant energy technologies for wastewater treatment plants that could represent decisive steps towards sustainability.

La chute chez les seniors constitue un problème de santé publique. Citée comme la seconde cause de décès accidentel dans le monde, elle concerne un tiers des Français de plus de 65 ans. Les séquelles physiques et fonctionnelles qui en résultent, les conséquences psychosociales nuisibles pour la qualité de la vie, la perte d’autonomie et son coût de prise en charge justifient l’attention qui lui est actuellement portée. Du point de vue du chercheur, les interprétations sous-jacentes à la surexposition des personnes âgées au risque de chute restent controversées, notamment parce que la compréhension de la coordination dynamique corporelle et de l’implication corticale lors du contrôle de l’équilibre est encore limitée. L’étude de la chute et des mécanismes qui y conduisent présente donc un double intérêt, fondamental et sociétal. Une chute survient si deux conditions sont réunies. La première est la perte initiale de l’équilibre, un ‘pré-requis’ qui peut toucher la population entière dans son quotidien. La seconde est un échec des mécanismes de rééquilibration, c’est à dire de la stratégie de réponse mise en œuvre pour compenser la déstabilisation : comment s’opère la sélection d’une stratégie de rattrapage, à partir de quelle appréciation du contexte et des informations sensorielles disponibles est-elle choisie ? qu’est ce qui assure son opérationnalité et garantit le rattrapage ou signe au contraire son échec ?...Pour répondre à ces questions, nous nous sommes donc intéressés à ce moment critique où il est encore possible de modifier l’issue finale par des ajustements posturaux et des actions motrices rapides et adéquats chez une population de jeunes adultes. La première étude est une analyse globale de la phase précoce d’une chute -abrégée par un harnais- (soit quelques centaines de millisecondes après la perturbation), afin d’évaluer la capacité du sujet à réagir à une perturbation imprévue et de développer des stratégies garantissant une protection efficace. Cette première étape se propose d’identifier les indicateurs discriminants et prédictifs d’une chute et d’un rattrapage au niveau neurophysiologique et biomécanique. Cette étude a également permis de mettre en évidence la présence d’un délai temporel incompressible appelé « phase passive », source de contraintes spatio-temporelles à l’expression complète d’une réponse posturale adaptée. Dans la seconde étude, de modélisation, nous avons élaboré un modèle mécanique personnalisé, construit à partir de radiographies tridimensionnelles non invasives du corps entier. Cette modélisation nous a permis d’analyser la contribution relative de propriétés biomécaniques passives et des synergies musculaires actives en jeu pendant les perturbations récupérables de l’équilibre ou non en comparant les résultats expérimentaux (‘réels’) obtenus à l’aide d’un dispositif asservi pour provoquer des chutes de plain-pied et la réponse théorique prédite (‘simulée’) à l’aide du modèle. Les résultats obtenus permettent de confirmer que le comportement du corps est en phase précoce-dicté par ses propriétés mécaniques, et peut être assimilé à un modèle simplifié. Après avoir mis en évidence l’existence d’une phase inertielle d’une durée équivalente à la moitié du temps disponible avant l’impact, notre questionnement s’est orienté vers le traitement de l’information en-cours lors de cette phase afin d’évaluer la contribution corticale alors que la réponse posturale évolue. La troisième étude consiste principalement à appréhender la charge cognitive impliquée dans le contrôle sensori-moteur, en particulier lors d’une chute, à l’aide du paradigme de double-tâche. En conclusion, à travers une approche pluridisciplinaire, les résultats obtenus dans cette thèse permettent d’émettre des recommandations intéressantes pour une prévention et une rééducation adaptée dans le but de contribuer à l’amélioration de la qualité de vie des personnes âgées. / A better understanding of what happens during an unintentional fall is relevant in preventing their occurrence. A fall is due to a failure of compensatory reactions to recover from postural perturbations during the descent phase which starts at the subject loss of balance point and lasts no more than 700-1000milliseconds [Hsiao, 1998]. The aim of the first study was to compare the biomechanical and muscular behavior during the pre-impact phase during non-recoverable falls and successful recovery trials. The experimental study aimed to evaluate the subject’s ability to distinguish in the first 500 milliseconds following the onset of perturbation a low-threatening perturbation from a high challenging one and can then predict the scenario that will more likely lead to a fall using specific motor strategies. In such a challenging task, we hypothesized that the constraints imposed by the biomechanical properties ultimately determine the ability to trigger efficient muscle activities. Full body 3D kinematics and associated muscle activities were collected in 30 young healthy subjects during fast and slow unpredictable multidirectional support-surface translations. 40 cm support-surface translations were used to evoke the balancing reactions (0,35 vs 0,9 m/s during resp. 1000 vs 500 millisecond The perturbation velocities were selected so that successful recovery should occur in milder trials whereas fast trials were sufficiently challenging to trigger non-recoverable falls. Analyses focused on the spatial and temporal characteristics of the Centre of Mass, angle variations, recovery step characteristics, and EMG activities (onset latencies and amplitudes) across each trial and muscle. Moreover, a 17-segment numerical and personalized model was created, based on stereoradiographic head to feet X-ray images followed by 3D-reconstruction methods to assess subject-specific geometry and inertial parameters. The outputs resulting from simulated falls allowed us to discard the contributions of the passive (inertia-induced) versus the active mechanisms (feedback-controlled and time-delayed neuromuscular components) of the response. The first outcome of that study was that the fall could be divided in distinct phases. For about 200 milliseconds following the onset of platform translation, the head remained stable in space. Similarly, the comparison with the simulated data supported that the CoM displacement matched the subject-dependant mechanical model. During a second phase of the fall, despite the fact that automated muscle postural synergies started at 80 milliseconds after perturbation onset, the trajectory of the body appeared to be exclusively dictated by its biomechanical properties. Later, muscle activities influenced the body trajectories, which consequently differed on a trial-to-trial basis. The simulation was in good agreement with the experimental results. The specificity of the postural response resulting in a strategy chosen to avoid a fall thus appeared in a late-phase, which can be explained because during a fall, the subjects had to prepare to the impact on the basis of sensory information that were not redundant but available in a sequential order: proprioceptive information appearing first while vestibular and visual information continued to signal a stabilized head in space. The sole proprioceptive information would be insufficient to trigger rapid and appropriate postural response. Moreover, in accordance with our results suggesting the importance of the late-phase and on-line controlled responses, a long inertial passive phase in the fast trials does not allow a large spatiotemporal window for compensatory reactions to occur. These could not only depend on the previously described automated postural synergies because the time constraints imposed by biomechanics permit in principle volitional motricity to play an important role very early in the fall. (...)

The diploma thesis deals with descriptions of vehicle - track dynamic interface. There are described basic analytical models of railway track. The numerical models are created by using finite element methods with moving load simulated axle of rail vehicle. The aim of thesis is to create the model which most accurately describes the dynamic phenomena in the track. The results from models are compared with data obtained by measuring in the track. Next aim of thesis is to determine dependency of rail cross-sectional characteristics on equivalent rail head wear and then on rail deflection.

<p dir="ltr">Positive displacement machines are used in various industries spanning the power spectrum, from industrial robotics to heavy construction equipment to aviation. These machines should be highly efficient, compact, and reliable. It is very advantageous for designers to use virtual simulations to design and improve the performance of these units as they significantly reduce cost and downtime. The recent trends of electrification and the goal to increase power density force these units to work at higher pressures and higher rotational speeds while maintaining their efficiencies and reliability. This push means that the simulation models need to advance to account for various aspects during the operation of these machines. </p><p dir="ltr">These machines typically have several bodies in relative motion with each other. Quantifying these motions and solving for their effect on the fluid enclosed are vital as they influence the machine's performance. The push towards higher rotational speeds introduces unwanted cavitation and aeration in these units. To model these effects, keeping the design evaluation time low is key for a designer. The lumped parameter approach offers the benefit of computational speed, but a major drawback that comes along with it is that it typically assumes fluid inertia to be negligible. These effects cannot be ignored, as quantifying and making design considerations to negate these effects can be beneficial. Therefore, this thesis addresses these key challenges of cavitation dynamics, body dynamics, and accounting for fluid inertia effects using a lumped parameter formulation.</p><p dir="ltr">To account for dynamics features related to cavitation, this thesis proposes a novel approach combining the two types of cavitation, i.e., gaseous and vaporous, by considering that both vapor and undissolved gas co-occupy a spherical bubble. The size of the spherical bubble is solved using the Rayleigh-Plesset equation, and the transfer of gas through the bubble interface is solved using Henry's Law and diffusion of the dissolved gas in the liquid. These equations are coupled with a novel pressure derivative equation. To account for body dynamics, this thesis introduces a novel approach for solving the positions of the bodies of a hydraulic machine while introducing new methods to solve contact dynamics and the application of Elasto Hydrodynamic Lubrication (EHL) friction at those contact locations. This thesis also proposes strategies to account for fluid inertia effects in a lumped parameter-based approach, taking as a reference an External Gear Machine. This thesis proposes a method to study the effects of fluid inertia on the pressurization and depressurization of the tooth space volumes of these units. The approach is based on considering the fluid inertia in the pressurization grooves and inside the control volumes with a peculiar sub-division. Further, frequency-dependent friction is also modeled to provide realistic damping of the fluid inside these channels.</p><p dir="ltr">To show the validity of the proposed dynamic cavitation model, the instantaneous pressure of a closed fluid volume undergoing expansion/compression is compared with multiple experimental sources, showing an improvement in accuracy compared to existing models. This modeling is then further applied to a gerotor machine and validated with experiments. Integrating this modeling technique with current displacement chamber simulation can further improve the understanding of cavitation in hydraulic systems. Formulations for body dynamics are tested on a prototype Gerotor and Vane unit. For both gerotor and vane units, comparisons of simulation results to experimental results for various dynamic quantities, such as pressure ripple, volumetric, and hydromechanical efficiency for multiple operating conditions, have been done. Extensive validation is performed for the case of gerotors where shaft torque ripple and the motion of the outer gear is experimentally validated. The thesis also comments on the distribution of the different torque loss contributions. The model for fluid inertia effects has been validated by comparing the lumped parameter model with a full three-dimensional Navier Stokes solver. The quantities compared, such as tooth space volume pressures and outlet volumetric flow rate, show a good match between the two approaches for varying operating speeds. A comparison with the experiments supports the modeling approach as well. The thesis also discusses which operating conditions and geometries play a significant role that governs the necessity to model such fluid inertia effects in the first place.</p>