A digital logic circuit tends to become slower if the voltage (VDD) level drops below the normal VDD level. Because of this, the required data will not have settled before the arrival of the clock edge. This results in an incorrect sampling of the data leading to a functional failure of the chip. This thesis proposes a clock controller circuit which solves this issue. It consists of a voltage monitoring circuit to track the variations in the VDD level, a frequency multiplier and divider, and a selector logic circuit that outputs a particular frequency depending upon the VDD range in which the chip is operating. / text

The implementation of high-speed passenger trains (HST) within existing highway right-of-way (ROW) offers a solution for regions with a demand for the capacity and service offered by HST but lacking the support for sharing freight rail ROW or acquiring new ROW corridors. The states of Florida, Colorado, California and Nevada propose to use highway ROW for their HST projects to increase the capacity of the corridor, prevent or minimize impacts and prevent disruption of freight rail operations. Despite the constraints of using existing highway ROW, such as speed-limiting degrees of curvature and safety concerns, solutions and mitigation measures exist. The purpose of this thesis is to present the HST projects in the United States proposing use of highway ROW, the potential benefits and engineering issues to consider and the feasibility of using the existing I-35 ROW in Texas for HST. / text

Oxide interfaces have attracted considerable attention in recent years due to emerging novel properties that do not exist in the corresponding parent compounds. Furthermore, modern atomic-scale growth and probe techniques enable the formation and study of new artificial interface states distinct from the bulk state. A central issue in controlling the novel behavior in oxide heterostructures is to understand how various physical variables (spin, charge, lattice and/or orbital hybridization) interact with each other. In particular, density function theory (DFT) has provided significant insight into underlying physics of materials at the atomic level, giving quantitative results consistent with experiment. In this dissertation using density functional theory methods, we explore the electronic, magnetic and structural properties developed near the interface in SrTiO3/LaAlO3, EuO/LaAlO3, Fe/PbTiO3/Pt, Fe//BaTiO3/Pt and Cs/SrTiO3 heterostructures. We study the interplay between physical interactions, and quantify parameters that determine physical properties of hetetrostructures. These theoretical studies help understanding how physical variables couple with each other and how they determine new properties at oxide interfaces. / text

This comparative research looks at intermedia agenda-setting effects between Internet bulletin boards and traditional news media, such as daily newspapers and broadcasting, in both the United States and Korea. By examining this intermedia relationship and the flow of influence by Internet bulletin boards on traditional media during presidential campaigns in the two countries, this dissertation study attempts to extend our knowledge of intermedia agenda-setting research. In addition, it also investigates, in reverse, the effects of daily newspapers and broadcasting on Internet bulletin boards. Finally, attention is given to different types of discussion cultures in the two countries. Results of this dissertation research indicated that there are intermedia relationships between Internet bulletin boards and traditional news media, such as newspapers and broadcasting, at the first and second levels of agenda setting using cross-lagged correlation comparisons. More specifically, at the first level of agenda setting in the United States, the results explained only the influence of newspapers on Netizen opinions posted on Internet bulletin boards. In summary, the results concerning issue agenda in the United States indicate that the U.S. Netizen concentrates more on the issue agenda of newspapers than of broadcasting. In the second level of agenda setting in the United States, cross-lagged correlation comparisons not only indicated the influence of both newspapers and broadcasting on opinions posted on Internet bulletin boards, but they also clarified it in this research. Formerly, there was no attempt to examine attributes of the intermedia agenda-setting functions of the U.S. media. This research now provides an explanation of the apparent relationship between traditional media and the Internet. At the first level of agenda setting in Korea, the result of the cross-lagged correlation suggested that Korean newspaper and broadcasting issue agenda influenced Netizen opinions on Internet bulletin boards. As the result of second-level agenda setting in Korea showed earlier, cross-lagged correlation comparisons presented intermedia agenda-setting functions between both newspapers and broadcasting, and Internet bulletin boards with each other. These findings contrast with results in the United States. / text

The performance of a horizontal axis marine current turbine is predicted by three numerical methods, vortex lattice method MPUF-3A, boundary element method PROPCAV and a commercial RANS solver FLUENT. The predictions are compared with the experimental measurements for the same turbine model. A fully unsteady wake alignment is utilized in order to model the realistic wake geometry of the turbine. A lifting line theory based method is developed to produce the optimum circulation distribution for turbines and propellers and a lifting line theory based database searching method is used to achieve the optimum circulation distribution for tidal turbines. A nonlinear optimization method (CAVOPT-3D) and another database-searching design method (CAVOPT-BASE) are utilized to design the blades of marine current turbines and marine propellers. A design procedure for the tidal turbine is proposed by using the developed methods successively. Finally, an interactive viscous/potential flow method is utilized to analyze the effect of nonuniform inflow on the performance of tidal turbines. / text

Can symmetry be utilized as a design principle to constrain evolutionary search, making it more effective? This dissertation aims to show that this is indeed the case, in two ways. First, an approach called ENSO is developed to evolve modular neural network controllers for simulated multilegged robots. Inspired by how symmetric organisms have evolved in nature, ENSO utilizes group theory to break symmetry systematically, constraining evolution to explore promising regions of the search space. As a result, it evolves effective controllers even when the appropriate symmetry constraints are difficult to design by hand. The controllers perform equally well when transferred from simulation to a physical robot. Second, the same principle is used to evolve minimal-size sorting networks. In this different domain, a different instantiation of the same principle is effective: building the desired symmetry step-by-step. This approach is more scalable than previous methods and finds smaller networks, thereby demonstrating that the principle is general. Thus, evolutionary search that utilizes symmetry constraints is shown to be effective in a range of challenging applications. / text

The presence of pharmacologically active and persistent compounds in drinking water sources is an environmental and public health concern. Sources of pharmaceuticals in the aquatic environment include wastewater treatment plant effluents and veterinary use. Antibiotics are of special concern because of their role in the spread of bacterial resistance. Conventional drinking water treatment processes are often ineffective for removing trace organic contaminants. Ozonation processes have demonstrated the ability to remove pharmaceutical compounds from drinking water supplies. During the ozonation of drinking water, the primary oxidants are ozone and hydroxyl radicals formed during the decomposition of ozone. Both oxidants contribute to the removal of pharmaceutical compounds; however, the relative rates of destruction by these two oxidants depends on the treatment operating conditions, the background water chemistry and the structure and reactivity of the target compound. This study investigated the relative impact of natural water characteristics, such as pH, the carbonate system, and natural organic matter, on the removal of the fluoroquinolone antibiotic ciprofloxacin by ozonation processes. Rate constants for k"O3, Cip obtained at pH 7 were approximately one order of magnitude higher than at pH 5 because ciprofloxacin changes from a positively charged cation to a neutral species over this pH range. The results showed that there was very little variation of the rate constants for ciprofloxacin oxidation by O₃ or hydroxyl radicals regardless of the carbonate concentration or the presence of the two organic matters studied in this research. Typical values for k"O3, Cip and k"HO°, Cip obtained at pH 7 ranged between 1.49x10⁴ and 1.64x10⁴ M⁻¹s⁻¹ and 1.29x10¹⁰ to 1.80x10¹⁰ M⁻¹s⁻¹, respectively. However, the presence of carbonate and other hydroxyl radical scavengers did have an impact on O₃ and hydroxyl radical exposure. The relative impact of these two oxidants changed depending on the pH of the system and the presence of carbonate and natural organic matter. / text

Since 2004, table-top laser-plasma accelerators (LPAs) driven by ˜30fs terwatt laser pulses have produced colimated, nearly mono-energetic eletron bunches with energy up to 1 GeV in laboratories around the world. Large-scale computer simulations show that LPAs can scale to higher energy while retaining high beam quality, but will require laser pulses of higher energy and longer duration than current LPAs. The group of Prof. Mike Downer, in collaboration with the Texas Petawatt (TPW) laser team headed by Prof. Todd Ditmire, is setting up an experiment that uses the TPW laser (1.1 PW, 150 fs) to drive the world’s first multi-GeV LPA. This thesis provides a general overview of the TPW-LPA project, including several diagnostic systems for the beam, plasma and laser pulse. Special attention is given to three of the diagnostic systems: (1)A transverse interferometry diagnostic of the plasma density profile created by the TPW laser pulse; (2)A Thomson scattering diagnostic of the self-guided path of the TPW laser pulse through the plasma; (3)An optical transition radiation diagnostic of the accelerated electron bunch exiting the plasma. In each case, basic principles, theoretical background, calculation and simulation results, and preliminary experimental results will be presented. / text

This thesis seeks to examine the Kurdish novel, The Flower of Shoran (1998) by Iranian Kurdish author, ‘Atā Nahāyi in the context of Kurdish identity search and nationalism and struggle to build a nation state. Considering that the setting of the novel is between the two World Wars which is arguably the most critical phase of Kurdish nationalism, the present study tries to give a brief overview of the historical events that shaped and oriented Kurdish nationalism. Subsequently, Nahāyi’s perspective on the question of Kurdish identity and nationalism in Iran which are the underlying themes of the novel is discussed. Also a detailed summary has been provided along with the translation of the first two chapters of the novel to illustrate how a fairly successful Kurdish novel such as The Flower of Shoran has dealt with the Kurdish question of identity and nationalism in the context of Kurds' struggle for autonomy and recognition as a distinct nation. / text

Estimation of static and dynamic petrophysical properties of multi-layer hydrocarbon reservoirs is crucial for the assessment of storage and flow capacities, compartmentalization, and for best primary or enhanced recovery practices. Interactive numerical simulation to reproduce field logs and core data is a reliable procedure to estimate static and dynamic petrophysical properties of complex rock formations. Previously, Voss et al. (2009) introduced the concept of Common Stratigraphic Framework (CSF) to construct and cross-validate multi-layer static/dynamic petrophysical models by invoking the interactive, numerical simulation of well logs both before and after invasion. This thesis documents the successful implementation of the CSF concept to examine and quantify the effects of mud-filtrate invasion on apparent resistivity, nuclear, and magnetic resonance logs acquired in San Martin, Cashiriari and Pagoreni gas fields in Camisea, Peru. Conventional petrophysical interpretation methods yield abnormally high estimates of water saturation in some of the reservoir units that produce gas with null water influx. This anomalous behavior is due to relatively low values of deep apparent electrical resistivity, and has otherwise been attributed to the presence of clay-coating grains and/or electrically conductive grain minerals. On the other hand, electrical resistivity logs exhibit substantial invasion effects as evidenced by the separation of apparent resistivity logs (both LWD and wireline) with multiple radial lengths of investigation. In extreme cases, apparent resistivity logs “stack” because of very deep invasion. We diagnose and quantify invasion effects on resistivity and nuclear logs with interactive numerical modeling before and after invasion. The assimilation of such effects in the interpretation consistently decreases previous estimates of water saturation to those of irreducible water saturation inferred from core data. It is shown that capillary pressure effects are responsible for the difference in separation of resistivity curves in some of the reservoir units. The final multi-layer CSF is in agreement with gas production measurements and permits reliable flow predictions to assist in reservoir engineering and production studies. / text