<p>The chief aim of this project is to investigate the groundwater flow dynamics of the various fractured-rock aquifers (deep and shallow) associated with Karoo dolerite ring complexes in the Qoqodala area (northeast of Queenstown in the Eastern Cape Province).</p>

On the Blue Nile in Sudan, near the Ethiopian border, there is a measurement station named El Deim. The discharge assessments carried out at this station are crucial for the water resource management in Sudan. Due to changed conditions, caused by a heightening of the downstream-located Roseires dam, new methods for discharge assessment are needed. The objective of the present study was to examine possibilities and methodologies to assess the discharge at this station. The flow dynamics was examined through steady state as well as dynamic hydraulic modeling by use of the Mike 11 modeling software package. By simulating possible future scenarios, in the aspect of discharge variations in the Blue Nile and water level variations in the reservoir, the effects from the raised dam on El Deim could be studied. The model was based on bathymetrical data in form of cross sections. As boundary conditions for the simulation, measured and synthetic data series of discharge and water levels were used. The known measured water levels at El Deim were compared with the simulated water levels at El Deim for the same discharge scenarios. The modeled value corresponds well to the measured values. The existing discrepancies between the simulated and measured values are likely caused by insufficient bathymetrical data.   Simulation results show that the flow dynamics at El Deim are highly dependent on the water level of the reservoir and the discharge’s rate of variation. Accordingly, rating curves were created for a range of water levels at the reservoir. With the use of these curves, and tables/equations based on them, the discharge can be rated by knowing the water level at the Roseires dam and El Deim. However, the results from this study are more a description of the principles of how the discharge ratings could be performed. If the methodology and rating tools from this study are planned to be implemented the model must be improved with more bathymetrical data. The improvements are needed to create more accurate curves, tables and equations for discharge rating. Discharge ratings can then be produced and enable better operation of Roseires dam and a more efficient use of the valuable water resources in Sudan. In order to test the applicability of the created model and produced rating tools they should be compared with new measurement data from El Deim with the heightened Roseires dam fully implemented.   It is possible to assess the discharge at El Deim even when backwater effects affect the station. The methodology developed in this thesis would be applicable for similar studies at other locations.

<p>The chief aim of this project is to investigate the groundwater flow dynamics of the various fractured-rock aquifers (deep and shallow) associated with Karoo dolerite ring complexes in the Qoqodala area (northeast of Queenstown in the Eastern Cape Province).</p>

Thesis (Ph. D.)--University of Canterbury, 2009. / Typescript (photocopy). Includes bibliographical references (p. 172-183). Also available via the World Wide Web.

There are a lot more roads being built periodically in most of the countries with the advancement of modern society. In order to promote the overall traffic flow quality within different cities, city traffic management has been playing a more and more essential role during the last few decades. In recent years, a significantly increasing attention has been paid to the management of traffic flow in major cities all over the world. In this thesis, we develop a stochastic dynamic model for urban traffic along with physical constraints characteristic of intersections equipped with traffic light. We assume that the incoming traffic to each stream in an intersection is amenable to the Poisson random process with variable intensity (mean). We introduce expressions for traffic throughput, congestion as well as operator's waiting time for the typical intersection in a city and hereafter define an appropriate objective functional. Afterwards, we formulate an optimization problem and propose the sequential (or recursive) algorithm based on the principle of optimality (dynamic programming) due to Bellman. The solution if implemented is expected to improve throughput, reduce congestion, and promote driver's satisfaction. Because the dynamic programming method is computationally quite intensive, we consider the scenario that one unit traffic stream stands for a specific number of vehicles which actually depends on the volume of traffic flow through the intersection. The system is simulated with inputs described by several distinct nonhomogeneous Poisson processes. For example, we apply the typical traffic arrival rate in Canada with morning peak hour at around 7:30 AM and afternoon peak hour at around 4:30 PM whilst it is also applied with morning rush hour at about 8:00 AM and afternoon rush hour at about 6:00 PM like in China. In the meanwhile, we also present a group of numerical results for the traffic arrival rates that have shorter morning peak-hour period but longer afternoon rush hour period. This may occasionally happen when there are some social activities or big events in the afternoon. In addition, another series of experiments are carried out to illustrate the feasibility of the proposed dynamic model based on the traffic arrival rates with only one peak-hour throughout the whole day. The system is simulated with a series of experiments and the optimization problem is solved by dynamic programming based on the proposed algorithm which gives us the optimal feedback control law. More specifically, the results show that both the optimal traffic light timing allocated for each stream and the congestion broadcast level (CBL) of each road segment during each time segment are found. Accordingly, the corresponding optimal cost can be found for any given initial condition. It is reasonably believed that this stochastic dynamic model would be potentially applicable for real time adaptive traffic control system.

Magister Scientiae - MSc / The chief aim of this project is to investigate the groundwater flow dynamics of the various fractured-rock aquifers (deep and shallow) associated with Karoo dolerite ring complexes in the Qoqodala area (northeast of Queenstown in the Eastern Cape Province). / South Africa

Polaritons are lightweight bosonic quasiparticles that result from the strong coupling of light with an exciton transition inside a microcavity. A sufficiently dense cloud of polaritons condenses into a polariton condensate, a state of matter showing macroscopic coherence and superfluid properties, whose dynamics are influenced by the cycle of constant pumping and decay of polaritons. This thesis begins with an introduction on the particle and wave properties of the polariton condensate, followed by a theoretical description of two-dimensional Bose-Einstein condensation (BEC) and a section on simulation of polariton condensates. The optical setup and the microcavity sample are presented thereafter, including holographic laser shaping with a spatial light modulator (SLM), which allows exciting the microcavity with arbitrarily shaped pump geometries. Experimental results comprise optical control of polariton condensates, and dipolaritons. First, optical blueshift trapping and energy synchronisation (phase locking) of condensates are introduced. The transition from phase-locked condensates to an optically trapped condensate is investigated for a configuration of N pump spots arranged on a circle of varying diameter. Differences between these two condensate types are highlighted in the discussion section. Next, two parallel pump laser lines with small separation are investigated, which create a one-dimensional waveguide with strong uniform gain. Optically guided polaritons are investigated in this configuration with respect to coherence, flow speed, temperature and chemical potential. Observations hint that coherence arises below the condensation threshold simply from the chosen geometry of the system. The final chapter is dedicated to dipolaritons (polaritons with a static dipole moment) which form when polaritons strongly couple to indirect excitons in coupled quantum wells. In this system quantum tunnelling of electrons can be controlled with bias voltage. This allows tuning the dipolariton properties optically and electrically, with exciting prospects for future experiments. A conclusion and outlook section rounds off this work.

The question of how ions interact with each other and with the potential energy barrier in thin lipid bilayer membranes has interested investigators for several years. The application of electrodiffusion theory to the study of this question is the central theme of this work. We have calculated current-voltage curves for barriers of various shapes and heights, in each case by means of numerically integrating the exact electrodiffusion equation as well as this same equation in the constant field approximation. We have also calculated the total charge in the membrane for the same conditions under which we have calculated the current-voltage curves.

Cardiovascular diseases, including heart failure, are a global health concern, necessitating advancements in non-invasive diagnostic tools and treatments. Computational modeling offers an invaluable approach to simulate and understand the intricacies of cardiac flow dynamics. This study aims to identify critical blood flow properties in the left atrium, a crucial component of the heart responsible for receiving oxygenated blood from the lungs and pumping it into the left ventricle. Building on previous work, this project implemented an idealized model of the left atrium using Finite Element Method (FEM) and simulated various properties related to its geometry, revealing crucial aspects of fluid dynamics. Specifically, analysis revealed a U-shaped inflow profile, pressure variations due to flow jets and presence of vortices, asymmetrical outflow due to differences in pulmonary vein geometry, and the presence of longitudinal vortex structures within the atrium. These properties can provide valuable insights about the blood flow in a healthy heart. This research presents a foundation for future work aiming to integrate models of the left ventricle and left atrium, offering a more comprehensive understanding of the left heart's functionality and potential pathologies. Further studies should focus on in-depth analysis, extension and validation of these properties using real patient data to enhance their diagnostic potential.

Turbulent swirling flows are important in many applications including gas turbines, furnaces and cyclone dust separators among others. Although the mean flow fields have been relatively well studied, a complete understanding of the flow field including its dynamics has not been achieved. The work contained in this dissertation attempts to shed further light on the behavior of turbulent swirling flows, especially focused on the dynamic behavior of a turbulent swirling flow encountering a sudden expansion. Experiments were performed in a new isothermal turbulent swirling flow test facility. Two geometrical nozzle configurations were studied. The \cb\ nozzle configuration exhibits a cylindrical \cb\ in the center of the nozzle. The free vortex nozzle configuration is obtained when the cylindrical \cb\ is removed. Detailed laser velocimeter measurements were performed to map out the flow field near the sudden expansion of the 2.9" (ID) nozzle leading to the 7.4" (ID) downstream section. In addition to presenting detailed flow profiles for both nozzle and downstream flow fields, representative frequency spectra of the flow dynamics are presented. Along with the flow time histories and histograms, the wide variety of dynamic behavior was thus described in great detail. The dynamics observed in the experiment can be classified into three main categories: coherent and large scale motion, intermittent motion and coherent periodic motion. Free vortex geometry flows, in the parameter space of the experiments (Swirl number = 0 - 0.21), exhibited mostly coherent and large scale motion. The spectra in these cases were broadband with very light concentration of spectral energy observed in some specific cases. Center--body geometry flows exhibited all three categories of flows as swirl strength was increased from zero. Flows with little or no swirl exhibited broad--band spectra similar to those for the free vortex geometry. Intermediate swirl levels resulted in a large amount of low frequency energy which, with the aid of the time histories, was identified as a large scale intermittence associated with radial movement of the annular jet as it enters the sudden expansion. Large swirl levels resulted in high magnitude coherent oscillations concentrated largely just downstream of the sudden expansion. Linear stability analysis was used to help in the interpretation of the observed dynamics. Although, as implemented here (using the parallel flow assumption), the analysis was not successful in quantitatively matching the experimentally observed dynamics, significant insight into the physical mechanisms of the observed dynamics was obtained from the analysis. Specifically, the coherent oscillations observed for larger swirl levels were able to be described in terms of the interaction between the inner and outer shear layers of the flow field. / Ph. D.