Model Predictive Control of Aerospace Systems

The primary objective of this thesis is to explore the fault tolerance capabilities of a state space formulation of MPC. Subsequent to a simulated control surface failure on the F-18 High Alpha Research Vehicle (HARV), the MPC controller will attempt to maintain stability and nominal performance while tracking a setpoint. Secondary objectives include studying the effect of data sample rate and MPC horizon lengths on system performance. These objectives will be accomplished using Matlab to develop the MPC controller and Simulink to demonstrate its effectiveness through simulation

Soil Temperature Mediated Seedling Emergence and Field Establishment in Bentgrass Species and Cultivars During Spring in the Northeastern United States

Reestablishment of damaged golf greens and fairways planted to creeping bentgrass (Agrostis stolonifera), colonial bentgrass (A. capillaris), and velvet bentgrass (A. canina) is a common practice following winter injuries. Identifying bentgrass species (Agrostis sp.) and cultivars with the potential to establish under low soil temperatures would be beneficial to achieving more mature stands earlier in the spring. Twelve bentgrass cultivars, including seven cultivars of creeping bentgrass (007, 13-M, Declaration, L-93, Memorial, Penncross, and T-1), two colonial bentgrass cultivars (Capri and Tiger II), and three velvet bentgrass cultivars (Greenwich, SR-7200, and Villa), along with \u27Barbeta\u27 perennial ryegrass (Lolium perenne) were evaluated for grass cover in the field during early spring. Bentgrass species and cultivars were seeded in the field at the same seed count per unit area. Soil temperatures were monitored in unneeded check plots from initial planting date on 8 Apr. to termination on 29 May 2013. Soil temperatures increased linearly during the 52-day experimental period from 4.7 to 23.5 degrees C. All species and cultivars emerged at approximate to 10 degrees C soil temperature. Bentgrass species and cultivars varied only 2 to 3 days in their initial seedling emergence, while days varied among bentgrasses from 5.5 days (to 10% cover) to 8.6 days (to 90% cover). All velvet bentgrass cultivars required higher soil temperatures (13.6 degrees C) and more time (26 days) following initial seedling emergence to establish to 90% cover in the early spring. Creeping bentgrass cultivars 007, 13-M, and Memorial, along with colonial bentgrass cultivars Capri and Tiger II, were statistically equal to \u27Barbeta\u27 perennial ryegrass in their capacity after seedling emergence to achieve faster cover at lower soil temperatures. Heavier (larger) bentgrass seed was associated with faster cover during the early stages of establishment, but seed size was uncorrelated with establishment during later stages from 50% to 90% cover

Multi-level Governance Processes - Citizens & Local Budgeting: Comparing Brazil, China, & the United States

Modifications to policy-making processes and actors are crucial when transitioning to multi-level governance. Civic engagement in budgeting processes, where crucial policy decisions are determined, is an important component of shared governance. Understanding the new roles for citizens in the budget process, then, can extend our knowledge of multi-level governance. This research explores the ways in which the budget process incorporates citizen participation to foster an ideal of civil society in the United States, Brazil, and China. The comparative case analysis probes the extent to which institutional changes have occurred, why they have occurred, and the degree to which municipal budget processes are characterized by multi-level governance

Storm Response of Fluvial Sedimentary Microplastics

Up to 80% of the plastics in the oceans are believed to have been transferred from river networks. Microplastic contamination of river sediments has been found to be pervasive at the global scale and responsive to periods of flooding. However, the physical controls governing the storage, remobilization and pathways of transfer in fluvial sediments are unknown. This means it is not currently possible to determine the risks posed by microplastics retained within the world’s river systems. This problem will be further exacerbated in the future given projected changes to global flood risk and an increased likelihood of fluvial flooding. Using controlled flume experiments we show that the evolution of the sediment bed surface and the flood wave characteristics controls the transition from rivers being ‘sinks’ to ‘sources’ of microplastics under flood conditions. By linking bed surface evolution with microplastic transport characteristics we show that similarities exist between granular transport phenomena and the behavior, and hence predictability, of microplastic entrainment during floods. Our findings are significant as they suggest that microplastic release from sediment beds can be managed by altering the timing and magnitude of releases in flow managed systems. As such it may be possible to remediate or remove legacy microplastics in future

Beyond the Property Tax: Local Government Revenue Diversification

Local governments in the U.S. rely less on the property tax than they have historically. This long-term trend has been accompanied by important shifts in the composition of local revenues. While the property tax still serves as one primary source of local government revenue, increasingly other sources are used to pay for local government. This paper first examines that trend, the forces behind it, and its regional impact. We then explore trends in three central states- Iowa, Nebraska, and Arkansas -- that have experienced substantial revenue shifts in recent years. A concluding section discusses the options for the future