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This thesis examines the relative importance of the inertial and geometric nonlinearities in modelling the dynamics of a flexible aircraft. Inertial nonlinearities are derived by employing an exact definition of the velocity distribution and lead to coupling between the rigid body and elastic motions. The geometric nonlinearities are obtained by applying nonlinear theory of elasticity to the deformations. Peters' finite state unsteady aerodynamic model is used to evaluate the aerodynamic forces. Three approximate models obtained by excluding certain combinations of nonlinear terms are compared with that of the complete dynamics equations to obtain an indication of which terms are required for an accurate representation of the flexible aircraft behavior. A generic business jet model is used for the analysis. The results indicate that the nonlinear terms have a significant effect for more flexible aircraft, especially the geometric nonlinearities which leads to increased damping in the dynamics.

This thesis examines the relative importance of the inertial and geometric nonlinearities in modelling the dynamics of a flexible aircraft. Inertial nonlinearities are derived by employing an exact definition of the velocity distribution and lead to coupling between the rigid body and elastic motions. The geometric nonlinearities are obtained by applying nonlinear theory of elasticity to the deformations. Peters' finite state unsteady aerodynamic model is used to evaluate the aerodynamic forces. Three approximate models obtained by excluding certain combinations of nonlinear terms are compared with that of the complete dynamics equations to obtain an indication of which terms are required for an accurate representation of the flexible aircraft behavior. A generic business jet model is used for the analysis. The results indicate that the nonlinear terms have a significant effect for more flexible aircraft, especially the geometric nonlinearities which leads to increased damping in the dynamics.

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Focusing on the city of Atlanta from 1972 to 2012, Halting White Flight explores the neighborhood-based movement to halt white flight from the city’s public schools. While the current historiography traces the origins of modern conservatism to white families’ abandonment of the public schools and the city following court-ordered desegregation, this dissertation presents a different narrative of white flight. As thousands of white families fled the city for the suburbs and private schools, a small, core group of white mothers, who were southerners returning from college or more often migrants to the South, founded three organizations in the late seventies: the Northside Atlanta Parents for Public Schools, the Council of Intown Neighborhoods and Schools, and Atlanta Parents and Public Linked for Education. By linking their commitment to integration and vision of public education to the future economic growth and revitalization of the city’s neighborhoods, these mothers organized campaigns that transformed three generations’ understanding of race and community and developed an entirely new type of community activism.

The United States Air Force has specified a need for the next generation, High Altitude, Long Endurance aircraft capable of carrying advanced sensor arrays over very large distances and at extreme altitudes. These extensive set of requirements has required a radical shift away from the conventional wing & tube configurations with a new focus placed on extremely light weight and unconventional structural and aerodynamic configurations. One such example is the Boeing Joined wing SensorCraft Concept. The Joined wing concept has potential structural and sensor carrying benefits, but along with these potential benefits come several challenges. One of the primary concerns is the aeroelastic response of the aft wing, with potential adverse behaviours such as flutter and highly nonlinear structural behaviour of the aft wing under gust conditions. While nonlinear computation models have been developed to predict these responses, there exists a lack of experimental ground and flight test data for this unique joined wing configuration with which to benchmark the analytical predictions. The goal of this work is to develop a 5m, scaled version of the Boeing Joined Wing configuration and collect data, through a series of ground and flight based tests, which will allow designers to better understand the unique structural response of the configuration. A computational framework was developed that is capable of linearly scaling the aeroelastic response of the full scale aircraft and optimize a reduced scale aircraft to exhibit equivalent scaled behaviour. A series of reduced complexity models was developed to further investigate the flying characteristics of the configuration, test avionics and instrumentation systems and the develop flight control laws to adequately control the marginally stable aircraft. Lessons learned were then applied the 5m flight test article that was designed and constructed by the author. In the final stage of the project, the decision was made to relax the aeroelastically scaled constraint in order to allow additional softening of the structure to further investigate the nonlinear behaviour of the aircraft. Due to the added risk and complexity of flying this highly flexible aircraft the decision was made to produce the final aeroelastically scaled article at the 1.85m scale. This model was designed, developed and ground tested in the lead up to a follow on project which will see additional flight testing performed in conjunction with Boeing Inc. / Graduate

The photodissociation of ozone by ultraviolet light has a great impact on the photochemistry of the atmosphere. The relative quantum yield for the production of the singlet atomic fragment O(¹D) has been determined in the wavelength region 306 to 327 nm for four temperatures between 227 K and 300 K. The technique of resonance enhanced multi photon ionisation (REMPI) was used to probe directly the O(¹D) photolysis product. These relative measurements have been placed onto an absolute scale by the selection of a calibration point whose value has been agreed by the scientific community. The yields obtained are in good agreement with others reported during the time of the research reported in this thesis and clearly show that three mechanisms contribute to the final quantum yield. Below 310 nm, O(¹D) is produced by a spin-allowed channel, above 320 nm the primary channel is a spin- forbidden one and at intermediate wavelengths photolysis of vibrationally excited ozone contributes to the O(¹D) yield. Elements of the quantum yield data presented in this thesis are being included in a new recommendation for the temperature dependent O(¹D) quantum yield. Details of the dissociation kinetics, including further evidence confirming the spin-forbidden channel, is presented in time-of-flight studies of the O(¹D) product. Time-of-flight profiles taken between 317 and 321 nm show evidence that, at room temperature, the O(¹D) quantum yield is anti-correlated with the ozone absorption cross section. Excitation of the O₂(a¹Δ_g) co-fragment has been observed at wavelengths below 296 nm by monitoring the energies of the O(¹D) formed. As the channel for the production of O₂(a¹Δ_g,andnbsp;vandnbsp;=andnbsp;1) opens, it is found that energy is preferentially partitioned into rotation of the O₂ fragment rather than into translation. Initial studies on the O(¹D) fragment have shown that the fragment is orbitally aligned and that the choice of REMPI transition can have a significant effect on the time-of-flight profiles and therefore on the measurements that are made from the profiles. The time-of-flight profiles obtained by probing the O₂(a¹Δ_g) photofragment have shown that the O₂(a¹Δ_g) has an angular momentum polarisation that is J dependent, with the even J being strongly polarised and the odd J depolarised. This results in the shape of the time-of-flight profiles being a function of the REMPI laser polarisation; and the study of this behaviour has been used to confirm the assignments in highly perturbed REMPI spectra.