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<p dir="ltr">LeadGlow (<b>LG</b>) was reported in 2009 for its ability to both sensitively and selectively detect Pb²⁺ in aqueous solutions. Utilizing the synthetic approach of <b>LG</b>, it is possible to generate a class of novel fluorophores. A derivative of first-generation <b>LG </b>was synthesized and reported here for the first time, intuitively named <b>LG2</b>. Both compounds contain interesting photophysical properties that have not been extensively researched prior to this work. Because of this, photophysical properties of both <b>LG</b> and <b>LG2</b> are unveiled here for the first time. These properties were investigated by determinations of quantum yield (QY), average fluorescence lifetime, and DFT calculations. <b>LG</b> was found to have a higher QY (0.057) than <b>LG2</b> (0.011); however, <b>LG2</b> displays an average fluorescence lifetime (3.186 ns) 5x greater than that of <b>LG</b>. Both <b>LG </b>and <b>LG2</b> are synthesized via Hg²⁺-facilitated desulfurization of their respective thiocarbonyls, resulting in a turn-on fluorescence feature. The thiocarbonyl-containing fluorophores (<b>SLG </b>and <b>SLG2</b>) display quenched fluorescence compared to their oxo-derivatives (<b>LG </b>and <b>LG2</b>), this work attempts to investigate the mechanism(s) responsible.<b> </b>A whole class of LeadGlow compounds can be synthesized and could be potentially used as fluorescence-based sensors.</p>

The objective of this research is to provide an in-depth analysis of the contact patch behavior of a specific passenger car tire. A Michelin P205/60R15 tire was used for this study. Understanding the way the tire interacts with the road at various loads, inflation pressures and driving conditions is essential to optimizing tire and vehicle performance. The footprint shape and stress distribution pattern are very important factors that go into assessing the tire's rate of wear, the vehicle's fuel economy and has a major effect on the vehicle stability and control, especially under severe maneuvers. In order to study the contact patch phenomena and analyze these stresses more closely, a finite element (FE) tire model which includes detailed tread pattern geometry has been developed, using a novel reverse engineering process. In order to validate this model, an experimental process has been developed to obtain the footprint shape and contact pressure distribution. The differences between the experimental and the simulation results are discussed and compared. The validated finite element model is then used for predicting the 3D stress distribution fields at the contact patch. The predictive capabilities of the finite element tire model are also explored in order to predict the handling characteristics of the test tire under different maneuvers such as pure cornering and pure braking. / Master of Science

Intrinsic quantum Thermodynamics (IQT) is a theory that unifies thermodynamics and quantum mechanics into a single theory. Its mathematical framework, steepest-entropy-ascent quantum thermodynamics (SEAQT), can be used to model and describe the non-equilibrium phenomenon of diffusion based on the principle of steepest-entropy ascent. The research presented in this dissertation demonstrates the capability of this framework to model and describe diffusion at atomistic levels and is used here to develop a non-equilibrium-based model for an isolated system in which He3 diffuses in He4. The model developed is able to predict the non-equilibrium and equilibrium characteristics of diffusion as well as capture the differences in behavior of fermions (He3) and bosons (He4). The SEAQT framework is also used to develop the transient and steady-state model for an open system in which oxygen diffuses through a tin anode. The two forms of the SEAQT equation of motion are used. The first, which only involves a dissipation term, is applied to the state evolution of the isolated system as its state relaxes from some initial non-equilibrium state to stable equilibrium. The second form, the so-called extended SEAQT equation of motion, is applied to the transient state evolution of an open system undergoing a dissipative process as well mass-interactions with two mass reservoirs. In this case, the state of the system relaxes from some initial transient state to steady state. Model predictions show that the non-equilibrium thermodynamic path that the isolated system takes significantly alters the diffusion data from that of the equilibrium-based models for isolated atomistic-level systems found in literature. Nonetheless, the SEAQT equilibrium predications for He3 and He4 capture the same trends as those found in the literature providing a point of validation for the SEAQT framework. As to the SEAQT results for the open system, there is no data in the literature with which to compare since the results presented here are completely original to this work. / Ph. D.

Several cascading outages that have occurred in the past have shown the importance of performing appropriate and coordinated transmission system planning between the different Planning Coordinators and Transmission Planners in a power system. In very large, interconnected systems, this coordinated planning is necessary due to the inherent complexity that characterizes non-lineal electric power systems. A major task in transmission system planning is to conduct contingency studies that would determine the consequences in the system when single or multiple of its elements trip due to failure or are disconnected during scheduled maintenance outages. This work develops general programs aimed at facilitating the performance of such contingency studies based on the latest Transmission System Planning Performance Requirement standard issued by NERC, TPL-001-4. The focus of this work is on the requirements for the steady state analysis described in the standard, which includes specific steady state performance planning events. The developed programs have been tested in a few base cases and have demonstrated their ability to facilitate contingency studies with any system regardless of its size. / Master of Science

The switching noise in a hard-switched point-of-load (POL) converter may result in false turn on, electromagnetic interference issues, or even device breakdown. A resonant cross-commutated buck (rccBuck) converter operates with low noise since all MOSFETs are turned on with zero voltage within a wide load range. A state-space model was developed to calculate the voltage gain, voltage stresses, and current stresses. Design guidelines for the rccBuck converter operating at continuous voltage mode or discontinuous voltage mode are provided. The design methodology of a one-turn inductor with significant ac and dc fluxes is given. Four fabricated one-turn inductors achieved 2.1% higher efficiency and 50% smaller total magnetic volume than the commercial inductors in the same rccBuck converter. The Omni-coupled inductors (OCI), composed of a twisted E-E core and PCB windings, further improve power density and efficiency. The core loss and inductances were modeled from a complex reluctance network. According to the loss-volume Pareto fronts, the total inductor loss was minimized within a smaller volume than that of discrete inductors. The expectations were validated by an OCI-based rccBuck converter switched at 2 MHz with 12 V input, 3.3 V at 20 A output, and peak efficiency of 96.2%. The small-signal model with a good accuracy up to half switching frequency was developed based on the averaged equivalent circuit. The transient performance of an rccBuck regulator is comparable to that of a second-order buck regulator with the same switching frequency, output capacitance, and closed-loop bandwidth. / Ph. D. / The switching noise in a hard-switched point-of-load (POL) converter may result in false turn on, electromagnetic interference issues, or even device breakdown. A resonant cross-commutated buck (rccBuck) converter operates with low noise since all MOSFETs are turned on with zero voltage within a wide load range. A state-space model was developed to calculate the voltage gain, voltage stresses, and current stresses. Design guidelines for the rccBuck converter operating at continuous voltage mode or discontinuous voltage mode are provided. The design methodology of a one-turn inductor with significant ac and dc fluxes is given. Four fabricated one-turn inductors achieved 2.1% higher efficiency and 50% smaller total magnetic volume than the commercial inductors in the same rccBuck converter. The Omni-coupled inductors (OCI), composed of a twisted E-E core and PCB windings, further improve power density and efficiency. The core loss and inductances were modeled from a complex reluctance network. According to the loss-volume Pareto fronts, the total inductor loss was minimized within a smaller volume than that of discrete inductors. The expectations were validated by an OCI-based rccBuck converter switched at 2 MHz with 12 V input, 3.3 V at 20 A output, and peak efficiency of 96.2%. The small-signal model with a good accuracy up to half switching frequency was developed based on the averaged equivalent circuit. The transient performance of an rccBuck regulator is comparable to that of a second-order buck regulator with the same switching frequency, output capacitance, and closed-loop bandwidth.

The United States Air Force is in the process of developing a more electric aircraft. The development of an aircraft Integrated Power Unit and an Internal Starter/Generator will be instrumental in producing sufficient electrical power to run all non propulsive systems. Iron-cobalt alloys, such as Hiperco&#61650; alloy 50HS, are high temperature, high strength magnetic materials ideal for these power applications. Design requirements and previous studies indicate that these materials need to survive in temperatures up to 1000&#61616;F (810K), rotation speeds of about 55,000 rpm, and have strengths in excess of 80 ksi. Research conducted by Fingers provided the material and creep properties used in the analysis presented in this report. The finite element method was used to analyze a spinning rotor mounted to a circular shaft via an interference fit subjected to various operating environments. The power law creep model defined by Fingers was used to analyze three distinct rotor configurations. The first configuration was a constant temperature single lamina, mounted to a shaft of equal thickness, subject to temperatures between 727K and 780K, rotation speeds between 35,000 rpm and 60,000 rpm, and two different interference fits: 0.0015 inches and 0.003 inches. The results yield conservative predictions that indicate that these models could not survive the required operating conditions. The second configuration was a linear radial variation in temperature single lamina, mounted to a shaft of equal thickness, subjected to three temperature ranges, rotation speeds between 30,000 rpm and 55,000 rpm, and two different interference fits; 0.0015 inches and 0.003 inches. These results represent a more realistic model, which indicate that the "cooler" inner portions of the rotor restrict the creep deformations of the "hotter" outer portions resulting in higher possible operating temperatures and rotation speeds very near the required operating conditions. The third configuration was a lamina stack comprised of two rotor lamina, with a Coulomb friction surface interaction, and held together by a compressive axial force. These models represent a first step towards understanding the behavior of the entire rotor stack. / Master of Science