2015 MU dissertations - Access restricted to MU
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Item From ionic liquid to deep eutectic solvent : greener than greener(University of Missouri--Columbia, 2015) Wang, Jing; Baker, SheilaOver the last decades, ionic liquids (ILs), molten salts with melting point below 100 [degrees] C, have attracted great attention due to their properties like negligible vapor pressure, high viscosity, high thermal conductivity, ionic conductivity and designable properties by varying the cations and anions, which enable them for abundant of applications as a new generation of green solvent. With further study, some problems of ILs start to expose, which mainly focus on the high cost, purity and toxicity. In the year of 2003, Abbott and coworkers reported a new kind of solvent with much lower freezing point formed with two solid components, choline chloride and urea, and they called it deep eutectic solvents (DES), which was considered to be a sub-category of ILs. Besides similar solvent properties with ILs, DES exhibits better biocompatibility and suitability for large scale applications. In replacement of conventional toxic organic solvent, ILs have been successfully utilized for various applications with the tag of greener solvent, and DESs are currently regarded as an option to ILs for similar applications but greener than ILs. This dissertation covers functional material applications, from ILs based to DESs based, from solvents to polymers, from greener to greener.Item Differences in processing of interactive infographics on different screen sizes and interface types(University of Missouri--Columbia, 2015) Myers, Rachel Lara; Thorson, EstherThis study investigated how the use of interactive media, specifically infographics, on touch screen devices of varying size affects the user's cognition. Such research fills a gap in research on both interactive graphics and touch screen interfaces. Two experiments were executed. In the first, a 3 (screen size) by 2 (interactivity), and the second, a 2 (interface type) by 2 (interactivity) experimental design with screen size and interface type tested between subjects and interactivity tested within subjects. Guided by Lang's (2000, 2006) Limited Capacity Model of Motivated Mediated Message Processing, cognition was measured based on the participant's encoding and storage of the information presented in the graphic. Multiple choice and openended questions related to information presented in the information graphic were used to measure encoding and storage. Psychophysiological measures of heart rate and skin conductance were recorded to measure participant's levels of attention and arousal throughout exposure to the infographics. Additionally, self-report questions were used to determine the participant's perception of the graphic, its content, and the site hosting the graphic, as well as how "interactive" they judged the graphic was. The results of these studies provide valuable insight into how individuals react to interactive media displayed on mobile devices. With the drastic increase in use of touch-based tablets and phones seen since the introduction of these products, the results from this project are a valuable resource in considering how to go about designing media that incorporate capabilities inherent in the touch screen interfaces of these devices.Item Robust and efficient process for acceptance testing of radiation therapy machines(University of Missouri--Columbia, 2015) Yaddanapudi, Sridhar; Mutic, Sasa; Loyalka, Sudarshan K.The current (legacy) paradigm for acceptance testing (AT), commissioning, and ongoing quality assurance (QA) and quality control (QC) of linac and treatment planning systems (TPS) is extremely inefficient requiring substantial labor efforts and significant expense for the testing equipment and software. Despite these efforts and capabilities of modern radiation therapy devices the AT, commissioning and ongoing QA/QC frequently result in errors leading to large variability in implementation of these systems. This dissertation intended to develop and validate a robust, efficient process for acceptance testing of radiation therapy machines using the electronic portal imaging device (EPID). The project aimed to 1) show that the variability in EPID response can be normalized and that EPID can be used for correlating beam energy changes, 2) show that AT of a linac can be automated and can be performed using EPID as the measurement tool, and 3) compare the current paradigm of AT to the new EPID-based AT approach by performing a failure mode effects analysis (FMEA). The presented work shows that EPID would serve as an excellent tool for monitoring changes in beam energy and for performing AT of a radiation therapy machine. The FMEA results showed a significant decrease in failure pathways for the EPID-based AT approach compared to the current paradigm. The EPID-based method of QA requires minimal time and the automation that is afforded through automatic machine setup greatly reduces chances of error associated with human driven processes. The work also showed that standardizing the process could reduce the variability in implementation and also reduce the dependency on 3rd party vendor tools.Item No people like #showpeople : Broadway performers' ethnographic social media(University of Missouri--Columbia, 2015) Spitulnik, Jennifer; Lawless, ElaineThe occupational folk group of Broadway musical theater performers uses folklore in public spaces as a kind of representational strategy for the group as a whole. This strategy is significant in representing the group’s identity to itself as well as to outsiders who are invested in knowing more about them, such as Broadway enthusiasts. That is, the group can and does tell the story of itself, representing itself ethnographically, by way of its individual members. Social media technologies provide a platform for Broadway performers to present these native ethnographies both to the public and to other members of the folk group. I argue that these native, self-conscious ethnographic works by musical theater performers are both concerned with representing themselves as individuals, and with representing the cultural group of musical theater performers as a whole. Exploring the folklore and folk identities performed by members of this group in online social media suggests new ways of understanding the politics and practices of ethnography, particularly on social network sites in our postmodern global economy of attention. In this project, the first in any field to consider musical theater performers as a cultural or folk group, I investigate actors’ recognition of and group use of vernacular creative expressions—folklore—as a representational strategy. Through this work, I explore the ways in which self-representation on the part of the ethnographic participants claims voice and authority for the group, while simultaneously performing group membership and identity for multiple audiences.Item Chief executive officers' courage(University of Missouri--Columbia, 2015) Rodriguez, Caroline; Johnston, JosephThe purpose of this study was to construct Chief Executive Officers' (CEOs) meanings of CEOs' courage. The focus was to understand courage from CEOs through their unique perspectives; therefore, the study was a constructivist study. Through qualitative semistructured interviews, the study noted the Personal Construct Theory (PCT) to establish what courage is, and is not, to the interviewees. For this study, a CEO was defined as “the highest-ranking executive in a company or organization, responsible for carrying out the policies of the board of directors on a day-to-day basis” (Pickett, 2006). Participants were 18 years of age and older, both male and female. Kelly's (1955) Repertory Grid Technique and Qualitative Content Analysis was used for data analysis. Six common themes emerged: Eye of the Tiger Spirit, Believe in Belief, Clarity and Acceptance of Self, Big Picture Perspective, Malleability of Hardiness, and Train Engine. The CEOs' elicited responses described CEOs' courage as having the attributes: ability to be resilient, conviction in their intentions, self-awareness, insightful, desire to improve/grow, and positive leadership. Trustworthiness of the Study was demonstrated by authenticity's criteria of fairness, ontological authenticity, educative authenticity, catalytic authenticity, and tactical authenticity.