"The problem investigated in this thesis is that of determining the impact of the disestablishment of Camp Edward Gary on the economy of the city of San Marcos, Texas...it is anticipated that this study may contribute two additional outcomes of value: the first is a test of certain ideas in economic theory pertaining to recessions; and the second is an evaluation of the data pertaining to the economy of small communities...the data presented in Chapter II and the summarization of that information in Chapter III lead to the inevitable conclusion that the deactivation of Camp Edward Gary caused a recession in the City of San Marcos, Texas, which was shared in varying degree by virtually every element of the economy...it is further concluded that the impact of the loss of the military community was modified to some degree by the beneficial effects of the growth in its educational institutions and the fact that the loss was shared, although in a lesser degree, by other communities in the general area." --leaves 4, 5, 79

Diese Dissertation besteht aus vier Aufsätzen, die einen Beitrag zur Literatur über die empirische Analyse von lokalen Arbeitsmärkten leisten. Der erste Aufsatz nutzt den Abzug eines Großteils der US-Stationierungsstreitkräfte in Deutschland seit 1990 als ein natürliches Experiment, das die Identifikation von kausalen Effekten von Nachfrageschocks in lokalen Arbeitsmärkten ermöglicht. Als Datengrundlage dient ein neu aufbereiteter Datensatz zu den regionalen Veränderungen der Personalstärke der U.S. Stützpunkte. Die empirischen Ergebnisse belegen, dass der Abzug zu einem signifikanten Rückgang der Beschäftigung in der lokalen Privatwirtschaft und einem nachfolgenden Anstieg in der lokalen Arbeitslosenrate führte. Im Gegensatz dazu weisen die Ergebnisse keine Evidenz für signifikante Anpassungen in den lokalen Löhnen oder Wanderungssalden auf. Der zweite Aufsatz vertieft die Frage der lokalen Lohnrigiditäten angesichts des Nachfrageschocks. Der Einfluss von zwei Institutionen wird als mögliche Quelle von heterogenen Lohnanpassungen in lokalen Arbeitsmärkten identifiziert. Die empirischen Ergebnisse zeigen, dass der Einfluss der beiden Institutionen isoliert mit keinen heterogenen Lohnanpassungen verbunden ist, aber das Zusammenwirken beider Dimensionen verbunden ist mit differenziellen Lohnreduktionen. Der dritte Aufsatz erweitert die Analyse der Folgen des amerikanischen Truppenabzugs um die Frage nach der Entwicklung der lokalen Kriminalitätsrate. Die Ergebnisse zeigen, dass der Truppenabzug mit einem Rückgang der Kriminalität insbesondere von Drogen- und Sexualstraftaten verbunden ist. Der vierte Aufsatz untersucht die langfristige Entwicklung der Zeitarbeit in den regionalen Arbeitsmärkten in Deutschland seit 1979. Dabei zeigt sich, dass die anfängliche Verteilung der Beschäftigungsanteile für manuelle Nicht-Routine- und Routine-Tätigkeiten eine starke Vorhersagekraft für das unterschiedliche regionale Beschäftigungswachstum von Zeitarbeit in Deutschland besitzt. / This thesis consists of four essays that contribute to the empirical analysis of local labor markets. The first essay exploits the massive withdrawal of U.S. Armed Forces in the aftermath of the German Reunification as a natural experiment that enables the identification of the causal impact of local labor demand shocks. It introduces a novel dataset that details the evolution of the U.S. manpower levels at the disaggregated regional level and thereby enables the measurement how U.S. base closures affected the demand for local non-tradable goods and services. The results from the empirical analyses suggest that the drop in local labor demand caused a significant loss of private sector employment and generated a subsequent rise in local unemployment rates. In contrast, wages and migration patterns do not exhibit any significant responses. The second essay further explores the rigidity of wages in local labor markets in response to the U.S. base closures. The presence of two types of institutions (i.e. works councils and the German Trade and Crafts Code) and their interplay are characterized as potential sources of wage heterogeneities. While in isolation these two institutions do not seem to alter the pattern of insignificant wage adjustments, their interaction is found to introduce a channel for small downward wage adjustments. The third essay is concerned with the change in local crime rates in response to the U.S. presence and withdrawal. The empirical findings suggest that the drawdown of the U.S. military presence can be related to large and significant drops in the local rate of drug and sex offenses. The fourth essay provides an empirical analysis of the diverging patterns of employment in temporary help services across labor markets in Germany over the last 30 years. The differential growth pattern both at the level of occupations and across regional labor markets are found to be related to the initial intensity of routine and non-routine manual tasks.

The history of the mining industry indicates a lack of understanding among the decision-makers of the impact the closure of mines has on the industry and the associated effects on the society and surrounding environment. The policies of the mining industry do make provision for a planned mine closure, but not for an unexpected closure. This detrimental aspect of closures in the mining industry is highlighted in the present study. The present study investigates how mineworkers’ dependency on their employment at a mine affects their ability to sustain their livelihoods. Vulnerable livelihoods leave the community at a greater risk to be affected by a disaster, than the livelihoods of a community that is resilient and has sustainable resources. Even though mineworkers are not considered as poor at the time of their employment, a mine closure could render them into a status called ‘transitional poverty’. This study also highlights that mineworkers who are skilled for mining operations only do not overcome the status of ‘transitional poverty’ and hence enter a phase called ‘chronic poverty’. This stage constitutes their inability to negotiate livelihood strategies and livelihood outcomes that could sustain a household. Thus humanitarian assistance would be needed from outside sources. Planning for unexpected mine closures should also be on the agenda of the mining industry due to the extreme consequences such an event holds for the mining community experiencing the event. In the case under investigation, the unexpected mine closures occurred in the Grootvlei mine in Springs and the Orkney mine owned by the Aurora Empowerment Systems Ltd. at the time of this study. These closures left the surrounding communities in need of food, shelter and clean water. The inhabitants gradually lost their livelihood assets. A contingency planning model is proposed at the end of this study to address the short-term and long-term consequences of an unexpected mine closure. / M Development and Management, North-West University, Potchefstroom Campus, 2014

No description available.

Nous présentons une approche alternative aux diagonalisations exactes de calculs en modèles en couches pour l'étude microscopique de la structure nucléaire. Nous avons tout d'abord minimisé l'énergie totale du système par la résolution des équations Hartree-Fock dans la base définie par l'espace de valence du modèle en couches. Nous avons finalisé la mise au point de ce programme par comparaison des résultats avec les solutions de problèmes solubles analytiquement comme ceux d'un hamiltonien SU(3) ou par comparaison avec des diagonalisations exactes du modèle en couches. Ensuite, nous avons mis au point des procédures pour l'obtention de ces mêmes calculs avec contraintes pour une description complète de la surface d'énergie potentielle d'un noyau donné en fonction des degrés de liberté Q20 et Q22. La restauration du moment angulaire par méthode de projections a permis d'obtenir les spectres des noyaux rotationnels dans le cas axial et dans le cas triaxial. Enfin, la méthode des coordonnées génératrices a permis le mélange de ces déterminants de Slater non orthogonaux. Parmi les différentes applications, nous avons pu décrire les noyaux déformés le long de la ligne N=Z autour du80Zr ou un nouvel îlot d'inversion à N=50. / We present an alternative approach to shell diagonalizations for microscopic description of nuclear structure. First we minimized the total system energy solving the Hartree-Fock equations within the shell model valence space. The results are compared with exact shell model diagonalization and an exact soluble SU(3) hamiltonian. Then, we developed procedures to obtain the same of type calculations with constrained conditions on the quadrupole degrees of freedom to obtain the full potential energy surfaces. The angular momentum restauration was obtained through projection method to generate rotionnal spectra of nuclei in both axial and triaxial cases. Finally the generate coordinate method was applied to mix several of these non-orthogonal Slater determinants. Among several applications we managed to describe deformed nuclei along the N=Z line around 80Zr or a new island of deformation at N=50. Finally, a first application in the superheavy region predicts a spherical gap for the Z=114, N=184 isotope

This thesis analyses major U.S. military bases closed by the Base Realignment and Closure (BRAC) Commission since 1988. The study focuses on geographic patterns of pre-existing versus BRAC bases, statistical attributes, environmental restoration, and reuse of bases. Comparative case studies supplement the analysis, highlighting rural versus urban location, success versus failure, politics, conflict, and local versus national goals. Thesis findings are that: 92 bases closed versus 97 commonly published; a fairly even national closure pattern occurred, indicating Commission efforts to achieve equity, except for three closure clusters indicating efforts to consolidate functions in some regions and leave others; base reuse, while commonly perceived negatively, has been positive in most cases; the BRAC process is becoming more efficient, such that allowed years between BRAC closure decisions and base closures should be reduced from six to three years to benefit both communities and the Defense Department.

De nos jours, la simulation des écoulements diphasiques a de plus en plus d’importance dans les chambres de combustion aéronautiques en tant qu’un des éléments requis pour analyser et maîtriser le processus complet de combustion, afin d’améliorer la performance du moteur et de mieux prédire les émissions polluantes. Dans les applications industrielles, la modélisation du combustible liquide trouvé en aval de l’injecteur sous forme de brouillard de gouttes polydisperse, appelé spray, est de préférence faite à l’aide de méthodes Eulériennes. Ce choix s’explique par les avantages qu’offrent ces méthodes par rapport aux méthodes Lagrangiennes, notamment la convergence statistique intrinsèque, le couplage aisé avec la phase gazeuse ainsi que l’efficacité pour le calcul haute performance. Dans la présente thèse, on utilise une approche Eulérienne basée sur une fermeture au niveau cinétique de type distribution Gaussienne Anisotrope (AG). L’AG résout des moments de vitesse jusqu’au deuxième ordre et permet de capter les croisements des trajectoires (PTC) à petite échelle de manière statistique. Le système d’équations obtenu est hyperbolique, le problème est bien-posé et satisfait les conditions de réalisabilité. L’AG est comparé au modèle monocinétique (MK) d’ordre 1 en vitesse. Il est approprié pour la description des particules faiblement inertielles. Il mène à un système faiblement hyperbolique qui peut générer des singularités. Plusieurs schémas numériques, utilisés pour résoudre les systèmes hyperboliques et faible- ment hyperboliques, sont évalués. Ces schémas sont classifiés selon leur capacité à traiter les singularités naturellement présentes dans les modèles Eulériens, sans perdre l’ordre global de la méthode ni rompre les conditions de réalisabilité. L’AG est testé sur un champ turbulent 3D chargé de particules dans des simulations numériques directes. Le code ASPHODELE est utilisé pour la phase gazeuse et l’AG est implémenté dans le code MUSES3D pour le spray. Les résultats sont comparés aux de simulations Lagrangiennes de référence et aux modèle MK. L’AG est validé pour des gouttes modérément inertielles à travers des résultats qualitatifs et quantitatifs. Il s’avère prometteur pour les applications complexes comprenant des PTC à petite échelle. Finalement, l’AG est étendu à la simulation aux grandes échelles nécessaire dans les cas réels turbulents dans le domaine industriel en se basant sur un filtrage au niveau cinétique. Cette stratégie aide à garantir les conditions de réalisabilités. Des résultats préliminaires sont évalués en 2D pour tester la sensibilité des résultats LES sur les paramètres des modèles de fermetures de sous mailles. / In aeronautical combustion chambers, the ability to simulate two-phase flows gains increasing importance nowadays since it is one of the elements needed for the full understanding and prediction of the combustion process. This matter is motivated by the objective of improving the engine performance and better predicting the pollutant emissions. On the industrial scale, the description of the fuel spray found downstream of the injector is preferably done through Eulerian methods. This is due to the intrinsic statistical convergence of these methods, their natural coupling to the gas phase and their efficiency in terms of High Performance Computing compared to Lagrangian methods. In this thesis, the use of Kinetic-Based Moment Method with an Anisotropic Gaussian (AG) closure is investigated. By solving all velocity moments up to second order, this model reproduces statistically the main features of small scale Particles Trajectories Crossing (PTC). The resulting hyperbolic system of equations is mathematically well-posed and satisfies the realizability properties. This model is compared to the first order model in the KBMM hierarchy, the monokinetic model MK which is suitable of low inertia particles. The latter leads to a weakly hyperbolic system that can generate δ-shocks. Several schemes are compared for the resolution of the hyperbolic and weakly hyperbolic system of equations. These methods are assessed based on their ability to handle the naturally en- countered singularities due to the moment closures, especially without globally degenerating to lower order or violating the realizability constraints. The AG is evaluated for the Direct Numerical Simulation of 3D turbulent particle-laden flows by using ASPHODELE solver for the gas phase, and MUSES3D solver for the Eulerian spray in which the new model is implemented. The results are compared to the reference Lagrangian simulation as well as the MK results. Through the qualitative and quantitative results, the AG is found to be a predictive method for the description of moderately inertial particles and is a good candidate for complex simulations in realistic configurations where small scale PTC occurs. Finally, within the framework of industrial turbulence simulations a fully kinetic Large Eddy Simulation formalism is derived based on the AG model. This strategy of directly applying the filter on the kinetic level is helpful to devise realizability conditions. Preliminary results for the AG-LES model are evaluated in 2D, in order to investigate the sensitivity of the LES result on the subgrid closures.

Tato práce představuje nové metody pro verifikaci programů pracujících s neomezenými celočíslenými proměnnými, konkrétně metody pro analýzu dosažitelnosti a~konečnosti. Většina těchto metod je založena na akceleračních technikách, které počítají tranzitivní uzávěry cyklů programu. V práci je nejprve představen algoritmus pro akceleraci několika tříd celočíselných relací. Tento algoritmus je až o čtyři řády rychlejší než existující techniky. Z teoretického hlediska práce dokazuje, že uvažované třídy relací jsou periodické a~poskytuje tudíž jednotné řešení prolému akcelerace. Práce dále představuje semi-algoritmus pro analýzu dosažitelnosti celočíselných programů, který sleduje relace mezi proměnnými programu a~aplikuje akcelerační techniky za účelem modulárního výpočtu souhrnů procedur. Dále je v práci navržen alternativní algoritmus pro analýzu dosažitelnosti, který integruje predikátovou abstrakci s accelerací s cílem zvýšit pravděpodobnost konvergence výpočtu. Provedené experimenty ukazují, že oba algoritmy lze úspěšně aplikovat k verifikaci programů, na kterých předchozí metody selhávaly. Práce se rovněž zabývá problémem konečnosti běhu programů a~dokazuje, že tento problém je rozhodnutelný pro několik tříd celočíselných relací. Pro některé z těchto tříd relací je v práci navržen algoritmus, který v polynomiálním čase vypočítá množinu všech konfigurací programu, z nichž existuje nekonečný běh. Tento algoritmus je integrován do metody, která analyzuje konečnost běhů celočíselných programů. Efektivnost této metody je demonstrována na několika netriviálních celočíselných programech.

This thesis presents elliptical rolling contact joints as an alternative to circular rolling contact and conventional revolute joints where high quality force transmission "low friction and backlash" with variable output are desired. Parameters specific to the joint and its position are developed in terms of relative link angles and elliptical surface geometry. These parameters are used to generate the basic forward kinematics for elliptical rolling link toggle mechanisms with oscillatory motion and high mechanical advantage. As large compressive loads are characteristic of such mechanisms, stress conditions are identified and principles for joint stability with variable, precision outputs are discussed. Finally, application is made to self-adjusting passive force closures with a case study of the MUSCLE Brake (Multi-toggle Self-adjusting Connecting-Linked Electromechanical) disc brake caliper. Elliptical rolling contact joints are shown to offer several benefits over circular rolling contact, including: reduced Hertz contact stresses and flexure bending stresses, variable output velocity, maximum use of contact interface by distributing small rotations across surfaces of small curvature, reduced forces on stabilizing members, increased mechanical advantage due to eccentricity, and no-slip pure rolling provided exclusively by connecting links (or flexures) without the need for gear teeth or friction.

<p dir="ltr">New system-level codes are being developed for advanced reactors for safety analysis and licensing purposes. Thermal-hydraulics of advanced reactors is a challenging problem due to complex flow scenarios assisted by free jets and stratified flows that lead to turbulent mixing. For these reasons, the 0D or 1D models used for reactor plena in traditional safety analysis codes like RELAP cannot capture the physics accurately and introduce a large degree of modeling uncertainty. System-level calculation codes based on the advection-diffusion equation neglect turbulent fluctuations. These fluctuations are extremely important as they introduce higher-order moments, which are responsible for vortex stretching and the passage of energy to smaller scales. Alternatively, extremely detailed simulations with velocity coupling from the Navier-Stokes equations are able to capture turbulence effects accurately using DNS. These solutions are accurate because they resolve the flow into the smallest possible length and time scales (Kolmogorov scale) important to the flow, which makes DNS computationally expensive for simple geometries and impossible at the system level.</p><p dir="ltr">The flow field can be described through a reduced-order model using the principles of statistical mechanics. Statistical mechanics-based methods provide a method for extracting statistics from data and modeling that data using easily represented differential equations. The Kramers-Moyal (KM) expansion method can be used as a subgrid-scale (SGS) closure for solving the momentum equation. The stochastic Burgers equation is solved using DNS, and the DNS solutions are used to calculate the KM coefficients, which are then implemented as an SGS closure model. The KM method outperforms traditional methods in capturing the multi-scale behavior of Burgers turbulence. The functional dependencies of the KM coefficients are also uniform for several boundary conditions, meaning the closure model can be extended to multiple flow scenarios. </p><p dir="ltr">For the case of the Navier-Stokes equations, each particle trajectory tends to follow some scaling law. Kolmogorov hypothesized that the flow velocity field follows a -5/3 scaling in the inertial region where Markovian characteristics can be invoked to model the interaction between eddies of adjacent sizes. This law holds true in the inertial region where the flow is Markovian. For scalar turbulence, the scaling laws are affected by thermal diffusion. If a fluid has a Prandtl number close to one, the thermal behavior is dominated by momentum, so the spectra for velocity and temperature are similar. For small Prandtl number fluids, such as liquid metals, the thermal diffusion dominates the lower scales and the slope of the spectrum shifts from the -5/3 slope to a -3 slope, also called the Batchelor region. System-level thermal hydraulics codes need to be able to capture these behaviors for a range of Prandtl number fluids. The KM-based model can also be used as a surrogate for velocity or temperature fluctuations in scalar turbulence. Using DNS solutions for turbulent channel flow, the KM model is used to provide a surrogate for temperature and velocity signals at different wall locations in the channel for Pr = 0.004, Pr = 0.025, and Pr = 0.71. The KM surrogate matches well for all wall locations, but is not able to capture the viscous dissipation in the velocity signal, or the thermal dissipation in the low Prandtl number cases. The dissipation can be captured by implementing a Gaussian filter.</p><p dir="ltr">Statistical mechanics-based methods are not limited to modeling turbulence in a reactor. Renewable power generation, such as wind, can be modeled using the Ornstein-Uhlenbeck (OU) method, which allows the long-term trends and short-term fluctuations of wind power to be decoupled. This allows for large fluctuations in wind power to be scaled down to a level that a reactor can accommodate safely. </p><p dir="ltr">Since statistical mechanics methods are based in physics, the calculated coefficients provide some information about the inputted signal. In a high-temperature gas-cooled reactor, strong heating can cause flow that is expected to be turbulent to show laminar characteristics. This laminarization results in reduced heat removal. The KM coefficients can be used to classify the laminarization from probed velocity signals more effectively than traditional statistical analyses.</p>