LOUIS University of Alabama in Huntsville
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Establishment and validation of a gas chromatography-mass spectrometry analytical method for targeted metabolomics: towards comprehensive profiling of metabolic signatures
Get PDFThis research aims to establish advanced analytical methods for targeted metabolomics using Gas-Chromatography-Mass Spectrometry (GC-MS). The focus is on quantifying key metabolites involved in specific metabolic pathways, optimizing sample preparation, and ensuring rigorous validation of method development parameters. By targeting thirteen specific metabolites, the research seeks to enhance metabolite extraction efficiency and analytical sensitivity. Analytical parameters such as selectivity, specificity, range, limit of detection, and limit of quantification were evaluated. This study\u27s findings will contribute to a more precise understanding of metabolic alterations in disease states and improve the robustness of GC-MS-based metabolomics
Constructing other worlds: an intertextual analysis of Cow Eye Press, Adrian Jones Pearson and the works of A.J. Perry
Get PDFCow Eye Press, A.J. Perry, and the pseudonymous Adrian Jones Pearson have largely been ignored by academics. Between 2001 and 2021, Perry composed a collection of texts which this study calls the Cow Eye Project. The project received brief attention when critics and journalists began comparing Pearson to Thomas Pynchon. However, the online spectacle overshadowed engagement with the texts themselves. This thesis exists to document the project and foreground Perry’s works on their own merits to examine their value and position within contemporary American literature. Previous scholars have treated the texts individually. This thesis argues that the central texts of the project, Twelve Stories of Russia, Cow Country, and The Old People, should be interpreted collectively—as a sequence of texts, or literary triptych—with which Perry challenges biography, authorship, structure, and form by blurring subject/object, fiction/nonfiction, and modernity/postmodernity through metatextual, intertextual and parafictional practices
Analyzing qualitative data collection methods in systems engineering
Get PDFThe goal of this thesis is to expand the research on human decision-making in engineering systems by exploring qualitative data collection methods utilized in systems engineering. Analyses are performed to identify differences in qualitative data collection method use across the life cycle and throughout technical processes. 495 sources were evaluated for qualitative data collection method use identified from systems engineering literature and analyzed using statistical analyses. Of these, 93 sources utilized data collection methods of documentary analysis, narratives, focus groups, observations, and interviews which traced across every life cycle phase and most technical processes. The findings show there are significant relationships between qualitative data collection method and both life cycle phase and technical process. By exploring the contemporary use of qualitative research methods in systems engineering contexts, researchers and practitioners gain a better understanding for expanding that use to enable a more human-centered design approach to complex systems
3D co-culture of human B lymphocytes with CD40L-expressing fibroblasts using an ultra-hydrophilic surface for in-vitro mimicry of secondary lymphoid organs
Get PDFB cells are critical components of the adaptive immune system that proliferate and differentiate within the secondary lymphoid organs. Traditional two-dimensional (2D) cell cultures fall short of replicating the intricate structures and dynamic evolution of 3D tissue environments, prompting more physiologically pertinent in vitro models. Our approach employs ultra-hydrophilic surfaces engineered from methacrylated N-hexanoyl glycol chitosan to cultivate a three-dimensional (3D) co-culture of CD40L-expressing MS5 stromal cells and naive B cells derived from the peripheral blood mononuclear cells (PBMCs) of healthy human donors. This novel system aims to mirror the structural and cellular intricacies of germinal centers within the secondary lymphoid organs. A comparative analysis was performed to evaluate the effects of 2D and 3D co-culture systems by examining B cell proliferation, differentiation, isotype class switching, and the creation of germinal center (GC) like structures. Our results indicate that the 3D co-culture model markedly improves the physiological accuracy of simulated germinal centers by enabling enhanced isotype class switching and differentiation into effector phenotypes. Notably, the 3D spheroids developed into dynamically evolving spatial organization akin to the dark and light zones found in natural germinal centers. There is tremendous potential to fine-tune the efficacy of this model by adjusting the dosage of CD40L and combinatorial variations of the soluble factors. Thus, this 3D model offers more authentic representations of B cell biology within the secondary lymphoid organs, which is potentially useful for advancing immunology research and the development of new immunotherapeutic strategies
Analysis of a magnetically enhanced microwave powered split-ring resonator plasma source for micropropulsion
Get PDFThis work focuses on better understanding split-ring resonators (SRRs) as plasma devices and exploring their use as a plasma source in a two-stage Hall thruster. This is done by first studying the effect of a single versus a coupled SRR on plasma production. Through the use of simulations in ANSYS HFSS and Langmuir probe measurements, it is found that coupled SRRs result in a more uniform plasma at higher pressures due to the introduction of a secondary ionization point, and the electromagnetic coupling resulting in a slightly stronger electric field being produced at the primary gap. Experiments were also done on the effect of operating at the first versus second mode. Simulations in ANSYS HFSS showed a better reflection coefficient response for SRRs operating at the second mode. This also resulted in a higher peak electric field between the gap of the SRRs. Langmuir probe measurements were taken in argon at 95 mTorr to quantify the effect of this on the plasma properties. Four cases were studied including SRRs that had their outer rings as the powered rings that were operating at the first and second modes and SRRs that had the inner ring powered and operating at the first and second modes. It was found that operating at the second mode resulted in higher peak densities, but the overall average density of the system was largely unaffected. Then, magnetic field cusps were added to the system in order to observe if the magnetic cusps could increase electron density by reducing diffusion. Laser collisional induced fluorescence was used to measure the electron density and electron temperature. It was shown that the electrons did become magnetized, but the magnetic field resulted in a reduction of the electron density which was believed to be caused by the magnetic field affecting the electromagnetic resonance of the system. Finally, the SRR was placed in a Hall thruster and plume measurements were taken with a Faraday probe and a retarding potential analyzer. The thruster was found to produce thrusts up to 87 μN and Isp up to 45 s
Mazda Toyota Manufacturing Laser Gauge Measurement Tools and Analysis
Get PDFhttps://louis.uah.edu/research-horizons/1366/thumbnail.jp
Development of a continuum damage constitutive model and simulation for brittle materials in space infrastructure application
Get PDFThe purpose of this work is to develop a continuum damage constitutive material model and apply it to structural response characterization of brittle materials for in-situ construction of space infrastructure. This research improves and expands the utility of the physics-based dominant crack algorithm (DCA) model in order to account for very low-strain rate phenomena in plain concrete structures. The DCA model is strain-rate dependent and has been effectively utilized for highly dynamic phenomena. The model has a strong basis in micromechanics and is able to capture the strain-softening response of brittle materials. The newly developed constitutive model can be easily implemented into a finite element analysis (FEA) platform to predict structural response. Simulation results show good correlation to plain concrete experimental data throughout the material response, including the full softening phase at quasi-static load conditions, and demonstrate the applicability of the model for the intended use. Plain concrete represents a comparable terrestrial construction material and serves as a good proxy to examine the validity of the model. Current research will benefit a growing research field of space habitat construction techniques with in-situ materials through additive manufacturing. The full characterization of material behavior is of vital importance for the structural integrity assessment of habitats and infrastructure that will assure human survival under very challenging environments, isolated in space and time from Earth
