2023 UMKC Theses - Freely Available Online
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Item Environment affects performance, fruit yields, and fruit chemistry of diverse american elderberry genotypes(University of Missouri--Columbia, 2024) Moore, Sydney Dru; Thomas, Andrew L.The production and consumption of American elderberry (Sambucus nigra subsp. canadensis) is increasing rapidly due to its health benefits and diverse array of value- added products. While production continues to increase, American Elderberry as a crop remains in the early stages of development. Identification of genotypes suitable for a range of hardiness zones is called for. The outcomes of this research will allow growers to plant genotypes that will have a high likelihood to perform at a high level in their geographic area. A genotype by environment study, that included 12 American elderberry genotypes originating from eight states, was established in the Spring of 2022. The study spans five environments located in Poteau, Oklahoma; Mt. Vernon, Missouri; New Franklin, Missouri; Champaign, Illinois; and Spring Green, Wisconsin. The dependent variables included plant growth, nutrient tissue testing, disease and pest incidence, phenology, fruit yield, and fruit quality. Significant differences were observed in most horticultural variables. Suitability analyses were completed to identify healthy, high yielding, and high anthocyanin genotypes at the differing locations. The most suitable genotypes for fruit production were identifies as 'Pocahontas', 'Cherokee', 'Ranch', and 'Hamilton'. The information gained from this study will help inform growers' planting decisions depending on their environment. The identified edaphoclimatic differences between environments can help distinguish if characteristics are genetically or environmentally controlled, which will aid in furthering breeding efforts. Tissue nutrient sufficiency status designation levels were developed with the tissue nutrient tests. These designation levels will aid producers in interpreting American elderberry foliar analysis results and to determine subsequent fertilization needs.Item Application of electromagnetic scattering reduction techniques for small unmanned aerial vehicles(2023) Chance, Alec Benjamin; Fields, TravisThis thesis focuses on the development and application of electromagnetic scattering reduction techniques, designs, and materials to small, relatively low-cost Unmanned Aerial Vehicles (UAVs). The application of electromagnetic scattering reduction methodologies to small UAVs poses a unique challenge over aircraft not designed for this purpose due to the size, cost, and weight constraints associated with these types of UAV systems. In order to develop operational UAVs with desirable electromagnetic scattering reduction qualities, an understanding of how an UAV interacts with electromagnetic waves that originate from a radio-frequency (RF) source is necessary. Armed with this knowledge, correlations can be drawn between the RF source and the electromagnetic scattering produced by the components commonly used inside of the UAV system in question. To best execute upon this goal, an electromagnetic scattering measurement setup must be assembled to collect the relevant information from the UAV of interest. This experimental measurement setup consists of a Vector Network Analyzer (VNA) to produce, transmit and receive an electromagnetic wave of a predefined frequency, a computer-controlled turntable and support structure. When this equipment is used in conjunction, the electromagnetic scattering response of a particular UAV can be measured at multiple incident angles, studied, and reduction techniques may be applied to reduce the baseline measurement. Once the electromagnetic scattering data has been collected from the UAV of choice, the results are broken down and the components that produce the largest magnitude of electromagnetic scattering returns are identified. In addition, the effects of different shapes on the electromagnetic scattering response are simulated to rapidly iterate upon novel designs. Each of the modified airframes are compared to the baseline measurements to evaluate the effectiveness of the electromagnetic scattering reduction techniques. The work described in this thesis advances the understanding of what electromagnetic scattering reduction modifications can be done to small UAVs without substantially undermining the performance or mission of the aircraft. Additionally, this document provides an insight on how to design a custom UAV to manage its own electromagnetic scattering signature without the utilization of exotic and expensive materials. The remainder of this thesis will be submitted to the Defense Technical Information Center (DTIC)Item An experimental study on the performance of existing and custom quiet propeller designs for unmanned aircraft systems(2023) Seagraves, Seth A.; Fields, TravisUnmanned Aircraft Systems (UAS), or drones, are being employed in a myriad of civilian and military applications including: aerial photographs of houses for real estate photography, videos of car chases, or package delivery. Package delivery provides unique challenges as the vehicle must be capable of carrying and delivering a payload in an (often) urban environment near non-participating bystanders. These larger UAS can produce significant acoustic signatures, which can deter operations in populated areas. The UAS propulsion system is the dominate acoustic source, and there is a need to reduce the acoustic signature of the propeller-motor system without dramatically reducing propulsion system performance. Several propeller design techniques were considered including: reducing the thickness of the propeller blade, increasing the sweep angle, and increasing the number of blades on the propeller. Further modification to the propeller design such as a boundary layer trip on the leading edge top surface or serrations to the trailing edge has been shown to reduce the sound radiated by the propeller. In total, 37 quiet propeller designs were created and simulated using SolidWorks Flow Simulation. From the simulation results, the three best performing designs were chosen to move on to manufacturing. Bringing these designs to life, a manufacturing process was devised and outlined which results in a carbon fiber composite prototype propeller. A custom semi-anechoic chamber testing environment was constructed which allowed for adequate airflow reducing the performance reducing effects of local pressure regions from the inlet and exhaust of the propeller while absorbing almost all sound radiated by the propulsion system. Custom propeller design, modification, manufacturing, and testing was done ultimately reducing the acoustic signature of a UAV propulsion system by up to 50% at a constant thrust and a minimum increase in consumed power by only 8.5%. The full version of this thesis will be uploaded onto the Defense Technical Information Center (DTIC). For more information please contact Dr. Travis Fields at fieldstd@umkc.edu.Item "Nobody Can Say It Wasn’t": Language of Power and the Bosnian Genocide, 1992–1995(2023) Van Cleave, Emily Elizabeth; Grieco, Viviana L., 1969-Between 1992 and 1995, Bosnian Serb nationalists, with aid from the Republic of Serbia, committed genocide against Bosnian Muslims in an effort to secure territory for a larger Serbian state. General debates over the definition and process of genocide frame specific studies of why and how Europe’s second genocide within fifty years occurred. This thesis argues that, during the Bosnian genocide, the rhetoric of genocide became a language of power that destroyed lines of communication between Bosnian Muslims and Bosnian Serbs, within the Bosnian Muslim community, and between American politicians and activists. In oral histories, interviews, public speeches, and court testimonies, Bosnian Muslims, Bosnian Serb nationalists, and Americans spoke about how the mass atrocity alienated them from each other. In the years since the genocide, a lack of a common understanding of the events has inhibited inter-ethnic healing within current-day Bosnia and Herzegovina. Curtailing nationalist sentiments is necessary to prevent the country’s rising tensions from reigniting the conflict. Preserving survivors’ experiences, especially through oral history, is key to proving that the genocide did occur and to helping individuals and communities heal.Item Bearing witness: essays, stories, and a novel in progress(2023) Zanders, Miriam A.; Pritchett, Michael, 1961-Storytelling is like the air that we breathe. We need the stories to thrive, to be enriched, and to grow like the plants and animals around us. Stories are the places where we are rooted. And to tell a story is to bear witness. It is also to testify to the spirits here and past. Seeing the telling and hearing the rhythms played out in the living and the dead silenced marks a place to begin anew. The only black and white is on the page. They are words, but also notes to a song that can be rearranged for another tune. You can sing it in celebration. It can be a dirge, crying the blues and shames. Much of what is told is out in plain sight, on the ground, in the sky, on all the life scratching and clawing out a living. Some of story is the silence rumbling beneath the surface of the noise. It’s an ache for the liberation of humanity from the cruelty of humans. These essays, stories and the novel in progress are an arrangement of the struggles, joys, the surviving and living through and past the pain. It is the telling of how marginalized people always rise above the oppressions even in death. Story keeps them alive. All the living is included in the symphony, the loving, hating, religion, history, herstory, shouting the chorus of existence seeking harmony with all the living on the earth and beyond.