2006 MU theses - Freely available online
Permanent URI for this collection
The items in this collection are theses that are available to the general public. Click on one of the browse buttons above for a complete listing of the works.
Browse
Recent Submissions
Item Coercive estimates for the Laplace-Beltrami operator(University of Missouri--Columbia, 2006) Quinn, Erin; Mitrea, Dorina"The layout of the thesis is as follows. In Chapter 1 we review some notation and basic definitions which are relevant to our work, and we prove a partition of unity result. Chapter 2 deals with the theory of integration on surfaces. Here we also show how to define a unit normal TV to a surface which is locally given by graphs of C^k functions, k > 2. For such surfaces we also have a local description of the unit normal 7 to the boundary of a surface. In Chapter 3, we discuss first-order tangential differential operators. Here we also prove that tangential operators annihilate functions which are constant on a surface. We begin Chapter 4 by proving the existence of a distinguished extension to a neighborhood of the surface of the unit normal to a surface. We then introduce the Gauss curvature for a surface and prove that it is actually the divergence of our extension of the unit normal. We finish the chapter by proving some useful properties of a particular family of tangential operators and defining the n x n matrix-valued function R which appears in the identities on surfaces we prove later in the thesis. Chapter 5 focuses on two integration by parts results. In Chapter 6 we prove identity (1.17). This is done using the formalism and properties of a particular family of operators (Dj)^nj = 1 defined here as well as the work done in previous chapters. We finish with Chapter 7 in which we prove Sobolev norm estimates on surfaces for solutions to the Poisson problem for the Laplace-Beltrami operator on surfaces with homogeneous Dirichlet, Neumann, and mixed boundary conditions."--Page 7.Item The evolution of a beat: a case study of changes in environmental reporting from the 1970's to today as evident in coverage of three disastrous oil spills(University of Missouri--Columbia, 2006) Jones, Tamsyn; Wilkins, LeeThe field of environmental journalism has significantly advanced since environmental issues emerged as topics of social and journalistic importance in the 1970's. Environmental reporters have become essential investigators of the human-environment relationship at a time when global environmental problems have become acutely complex. Yet, despite noticeable improvements, environmental reporters continue to wrestle with some of the same reporting challenges afflicting the beat since the beginning - especially in the area of environmental disaster reporting. Society is now approaching a critical juncture when the decisions and actions of people on the planet today will determine the quality of life for generations to come. Conveying the importance of these problems requires highly competent reporting capable of dealing with the unique issue complexities. To assess how environmental reporters have adapted to the changing rigors of environmental news, this thesis analyzes how environmental reporting has changed over three decades. Three disastrous oil spills throughout the beat's history are qualitatively analyzed via comprehensive textual analysis in two quality newspapers, the Seattle Times and the UK Guardian. The chosen spills include: the 1978 Amoco Cadiz; the 1989 Exxon Valdez; and the 2002 Prestige. Oil spills are inherently complex, and thus are ideal as models of how environmental reporters dealt with a complex problem. Results indicate a significant improvement in quality of coverage between 1978 and 1989 in both newspapers, including a shift to focusing on systemic causes and local perspectives. Easy journalistic templates were abandoned in favor of probing independent reporting. Fostering of regional identities emerged as related to higher quality reporting. Quality reporting persisted through 2002, including additional efforts to improve, suggesting that papers can improve dramatically if attentive to reporting practices.Item A comparison of Nebo Hill and Sedalia points(University of Missouri--Columbia, 2006) Parks, LuElla Marie; O'Brien, Michael J. (Michael John), 1950-Classification of Nebo Hill and Sedalia points as separate types has been the subject of debate among archaeologists. Some argue that identification of two point types is erroneous and there is only one type with a wide range of measurable variation; whereas, others propose differences that can be verified by measurements. Differences between the two groups previously have been attributed to isolation and drift. Current research supports earlier studies that proposed measurable differences between the two point classes based on maximum width and geographical distribution. However, additional emphasis on other traits together with observations on reworking of the proximal portion of these points provides supplementary explanations for the differences, as well as the similarities. The relationship between the distribution of Phragmites australis, or common reed, and Nebo Hill points offers an explanation for the change in form founded on a possible intensification in the occurrence of socket hafting.Item Relation of Missouri river flows to sandbar morphology with implications for selected biota(University of Missouri--Columbia, 2006) Tracy-Smith, Emily; Galat, David L.Channel modification and flow regulation in historically braided large rivers, have reduced sandbars and associated highly productive habitats for riverine biota. Sandbars are an important interface between aquatic and terrestrial environments, i.e. an aquatic-terrestrial zone (ATTZ), within the main channel of the lower Missouri River. Predictive models of sandbar morphometry (area, wetted perimeter, elevation, and water-surface slope) were developed to determine how changes in discharge affect the quantity of submergent-sandbar ATTZ (depth) and emergent-sandbar ATTZ (elevation) for point and wing-dike sandbars within a segment of the lower Missouri River. Point sandbars were as much as 22 times greater in mean area than wing-dike sandbars for submergent and emergent ATTZ, whereas wing-dike sandbars were more abundant, composing 85% of all sandbars in the Grand River to Osage River segment of the lower Missouri River. Reduced summer flows associated with alternatives GP1528 and GP2021 increased available wetted perimeter in July and August for post breeding wading birds and during the beginning of autumn shorebird migration while also creating more emergent sandbar habitat during softshell turtle nesting. Flows under the current flow regime and selected management alternatives provided greater area of submergent-sandbar ATTZ during the initial months of age-0 riverine fish nursery than historical flow conditions under ROR.Item Modern control design for a variable displacement hydraulic pump(University of Missouri--Columbia, 2006) Dean, Patrick T., 1982-; Fales, RogerIn this work modern control methods are used to design and analyze control methods for a variable-displacement hydraulic pump. More accurate uncertainty descriptions are derived by using a structured uncertainty model as opposed to an unstructured uncertainty model. The system studied includes one variable-displacement swash-plate hydraulic pump with a constant engine speed model. The input to the system is the current actuating the control valve position, while the system output is the discharge pressure of the pump. The established PID controller design lacked robustness, encouraging design of a two degrees-of-freedom control scheme. Frequency domain tests show robustness improvement over the classical PID control scheme. Time domain results show similar performance from both the PID controlled system and the two degrees-of-freedom controlled system. Time domain tests also show improved robustness to parametric variation from the modern control method, while system responses to large disturbances are similar among both the classical and modern control schemes.