2007 MU theses - Access restricted to MU
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Item Blast resistant design for roof systems(University of Missouri--Columbia, 2007) McClendon, Mark Andrew; Salim, Hani A., 1966-[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] The design of structures to resist explosive loads has become more of a concern to the engineering community. This research focuses on the design techniques for the loading on roof structures and the resistance of open web steel joists. A procedure has been developed to devise a uniform dynamic load on a roof that matches the response from blast loads. This research uses finite element analysis to evaluate the responses from numerically calculated blast loads and compares them to the equivalent loading response and the response of experimentally measured roof blast pressures. While the responses from finite element modeling matched the experimental responses, the equivalent loading procedure did not adequately predict the initial peak deflection or the maximum deflection. The response of several structural members used in roof construction, such as hot-rolled steel beams and reinforced concrete slabs, are well documented and understood. Open web steel joists (OWSJ) are other types of common roof components. Their responses under loading are not clearly defined, and current methods extrapolate techniques used in the design and analysis of hot-rolled steel beams and reinforced concrete. It is believed that the failure mechanisms of OWSJ significantly are not accurately being taken into account. The resistance function is computed from three tests and compared to current methodologies. It is recommended that an analytical resistance function for OWSJ be clearly defined, which includes all failure limit states.Item Improving performance for adaptive filtering with voice applications(University of Missouri--Columbia, 2007) Oddiraju, Swetha, 1981-; Ho, Dominic K. C.[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Adaptive filtering is a common solution to many signal processing applications in which the environments are time varying. Its performance is limited by the misadjustment. A method to reduce the misadjustment when the additive noise in the desired signal is correlated is investigated in this work. The proposed method consists of two adaptive components: a modeling filter and a noise whitening filter. The proposed method performs better than the conventional LMS and RLS algorithms both in convergence speed and misadjustment factor. The performance of the adaptive filter when updated using LMS is observed. The improvement factor is proportional to the ratio of the noise power to white innovation power in the desired signal. The reduction in gradient noise allows larger step size, thus increasing the overall performance of the system. Both theoretical and simulation results proved that the proposed method gives a smaller misadjustment and better tracking capability than existing methods.Item Activation of astrocytes: involvement of NADPH oxidase and cytosolic phospholipase A2(University of Missouri--Columbia, 2007) Hu, Chunhua; Sun, Grace Y.[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Reactive oxygen species (ROS) are produced in cells by enzymic and non-enzymic mechanisms and play important roles in the pathogenesis of neurodegenerative diseases. However, mechanisms for the increase in ROS and their effects leading to altered cell metabolism have not been studied in detail in the central nervous system. In the first series of studies, we examined ROS production in primary rat astrocytes and their downstream effects on changes in signaling cascades and morphology using menadione. ROS production induced by menadione was completely inhibited by NADPH oxidase inhibitors including apocynin and gp91ds-tat. Menadione also stimulated phosphorylation of p38 and ERK, and caused actin polymerization and which can be inhibited by inhibitors for NAPDH oxidase and MAPK. In the second part, we tested the role of cytosolic phospholipase A2 in astrocytes in response to oxidative stress. Menadione increased the immunoreactivity of phospho-cPLA2 and caused plasma membranes to become more gel-like, which were abrogated by down regulating cPLA2 with siRNA. In summary, our study demonstrated the important role of NAPDH oxidase in production of ROS and their link to activation of MAPK pathways and cPLA2 in astrocytes. We further demonstrated that excess production of ROS, such as that mediated by menadione, can alter cell membrane properties, morphology, and cytoskeletal arrangement and in turn cell death mechanism.--From public.pdfItem Distance and disparity: social disadvantage and the distribution of hazardous waste in America(University of Missouri--Columbia, 2007) Vlahiotis, Anna; Hermsen, Joan M.[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] Since the original studies of environmental discrimination were completed in the early 1980s, many scholars have measured disproportionate proximity to hazardous waste by poor and minority communities. The majority of this research has found evidence to support claims of environmental injustice, yet no research to date has examined the role of residential segregation in producing or proliferating environmental inequities. This research has addressed this limitation by systematically testing racial residential segregation as part of a more rigorous measurement of the theoretical constructs of environmental inequality, and by measuring each of the theoretical constructs in counties where hazardous waste facilities are owned or operated by the federal government. The results of multivariate analyses suggest that proximity to hazardous waste emissions inequitably burdens racial minorities and segregated residents, even when controlling for urbanization and local industry. Evidence of inequalities in counties with federal facilities was inconclusive.Item Regional variation in protopalatial Crete?: a comparison of Minoan domestic and funerary architecture in Eastern and Central Crete(University of Missouri--Columbia, 2007) Livingston, Kathryn Jane; Langdon, Susan Helen, 1952-[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT AUTHOR'S REQUEST.] This study investigates the existence and extent of regional variation in Crete in the Protopalatial period (Middle Minoan IB-II) as reflected in the material record besides pottery. It examines funerary and domestic architecture, as well as burial practice in eastern and central Crete. Examining both domestic and funerary architecture along with mortuary ritual and burial practice leads to a more thorough understanding of the extent of regional variation in Protopalatial Crete than an examination of any of these aspects alone. This study describes the excavated and published remains of two settlements in each region, considering the floor plan and number of storeys of the houses themselves as well as their arrangement within the settlement and the influence of the landscape on the layout of the settlements in order to establish the basic characteristics of the settlements in that region. This study also makes use of the typology of Minoan houses developed by John McEnroe in his 1979 Ph.D. dissertation and an article published in 1982. This study describes one cemetery in each region to act as a representative of cemeteries in that region. The survey includes the main type of tombs, and evidence of burial practice as shown by grave goods, number of burials per tomb, treatment of the area around the door of the tomb, and other aspects of burial practice. The same aspects of this cemetery are then briefly compared to those of others in the region in order to help further establish the characteristics of the region.