http://hdl.handle.net/10150/129649 2026-04-12T23:04:12Z 2026-04-12T23:04:12Z Uppnor, Sumedha http://hdl.handle.net/10150/679932 2026-04-05T01:10:26Z 2025-01-01T00:00:00Z

OPTOMECHANICAL DESIGN SOLUTIONS FOR FIREBALL-2 SPECTROGRAPH ALIGNMENT VERIFICATION AND CONTROLLED-ENVIRONMENT TRANSPORT OF ASPERA UV FLIGHT OPTICS Uppnor, Sumedha Optomechanical design integrates the precision of optical science with the practicality of mechanical realization, ensuring that theoretical designs perform reliably under real-world conditions. It governs alignment, stability, and environmental resilience, factors that directly define the success of complex instruments used in space missions and laboratory research. This thesis presents two representative optomechanical systems developed for ultraviolet (UV) astronomical instrumentation. The first, the FIREBall-2 (FB-2) telescope simulator, is a portable analog of the balloon-borne UV telescope. Roughly ten times smaller than the 1-m primary and 1.2-m siderostat mirror system, it reproduces their optical behavior and provides arcsecond-level tip-tilt control for alignment verification of the UV spectrograph. The system’s optomechanical layout, degrees of freedom, and alignment campaigns at the University of Arizona and the California Institute of Technology are discussed. The second project concerns nitrogen-purged shipping containers for the Aspera SmallSat mission UV coated flight optics. To protect hygroscopic Al+eLiF coatings prior to MgF$_2$ encapsulation, custom containers and preparation procedures were developed to maintain relative humidity below 5\%. The design limited reflectance degradation to less than 1.1\% after encapsulation, as observed on calibration coupons, validating the controlled-environment approach. Together, these projects demonstrate how carefully engineered optomechanical solutions, are essential to achieving and preserving optical performance throughout the project lifecycle.

2025-01-01T00:00:00Z Ochoa, Tina http://hdl.handle.net/10150/679931 2026-04-05T01:10:17Z 2026-01-01T00:00:00Z

ABSOLUTE RADIOMETRIC CALIBRATION SENSITIVITY ANALYSIS OF VANTOR’S SURFACE REFLECTANCE PRODUCT Ochoa, Tina This thesis evaluates the accuracy and sensitivity of Vantor’s Atmospheric COMPensation (ACOMP) surface reflectance product, a key component in enabling consistent, analysis-ready Earth observation data. Vantor performs absolute radiometric calibration using the vicarious method at its site at Colorado Air and Space Port (CASP) in Watkins, CO over specialized reflectance targets. The radiometric performance of ACOMP-derived surface reflectance is assessed using in-situ reflectance measurements collected at a farmed vegetative field at CASP, along with RadCalNet (RadCalNet) observations of the stable natural target Railroad Valley (RVUS). The analysis quantifies how well these products reproduce ground-measured reflectance under varying atmospheric and viewing conditions.A central focus of this work is the influence of absolute radiometric calibration coefficients on surface reflectance outputs. To characterize this relationship, a Monte Carlo sensitivity analysis was conducted that systematically perturbs calibration coefficients across a range of plausible uncertainty thresholds. This approach isolates the extent to which calibration uncertainty propagates into downstream reflectance products and identifies spectral regions and product types most affected by radiometric variability. The results provide an empirical basis for understanding the robustness of ACOMP’s atmospheric correction framework and highlight the critical role of accurate vicarious calibration in ensuring radiometric fidelity. These findings support ongoing efforts to refine calibration strategies and improve the consistency of Vantor’s reflectance products across sensors and acquisition conditions.

2026-01-01T00:00:00Z Restrepo Marulanda, Jose Andres http://hdl.handle.net/10150/679930 2026-04-05T01:10:10Z 2025-01-01T00:00:00Z

Evaluating Catch Bench Effectiveness and Rockfall Retention Strategies Using Field-Calibrated Rockfall Models Restrepo Marulanda, Jose Andres Rockfall hazards represent one of the most persistent safety concerns in open-pit mining, threatening personnel, equipment, and production efficiency. This thesis evaluates the effectiveness of catch benches and flexible barrier systems using field-calibrated numerical modeling. The research integrates experimental rockfall data collected at Bald Mountain Mine, Nevada, through the National Institute for Occupational Safety and Health (NIOSH) project Highwall Safety: Rockfall Catchment Design and Slope Performance Monitoring. The first study focuses on the calibration of a two-dimensional rockfall model in RocFall2 by matching field test results from controlled drop experiments, establishing restitution and friction parameters representative of actual slope conditions. Beyond evaluating the performance of the first catch bench, this study also examines the proportion of blocks retained on the subsequent benches, providing a broader understanding of cumulative catch efficiency across the slope. The calibrated model determined that 90 % of 6-inch synthetic blocks were retained within 10.9 m of the bench toe, defining a benchmark for performance evaluation. This framework was then applied to assess how variations in bench geometry, barrier height, and barrier placement affect rockfall containment. Twenty-four simulations combining different bench and barrier configurations revealed that specific bench–barrier combinations can maintain containment levels close to the 90 % benchmark, even under geometrically constrained conditions. The findings demonstrate that barriers can compensate for reduced bench width, providing a practical approach for achieving safety goals while supporting steeper slope designs and improved ore recovery. Overall, this research highlights the value of field calibration in enhancing model reliability and bridging empirical design criteria with numerical analysis. The results contribute to the development of performance-based methodologies for rockfall hazard mitigation, supporting safer and more efficient slope-design practices in modern open-pit mining.

2025-01-01T00:00:00Z Charpentier, Phoebe http://hdl.handle.net/10150/679929 2026-04-05T01:10:03Z 2026-01-01T00:00:00Z

The Canon of Contemporary Native American Women Artists: An Examination of Exhibition History and Social Contexts Charpentier, Phoebe The canon of contemporary Native American women artists formed differently than the traditional, Western art historical canon. This canon has been deliberately constructed through strategic interventions by artists, curators, and scholars—many of them Native women themselves—who recognized that existing art historical frameworks were fundamentally inadequate for understanding their work. Unlike the Western canon, which developed over centuries through gradual critical consensus, the canon of contemporary Native women artists can be traced through its exhibition history which reveals curatorial practices/interventions that broke from the art historical mechanisms traditionally utilized in fine arts contexts. Drawing on three interconnected theoretical frameworks developed by Indigenous scholars—visual sovereignty (Jolene Rickard), Indigenous feminisms (Nancy Marie Mithlo), and place-thought (Vanessa Watts)—this thesis traces the history of five landmark exhibitions over a 34 year period, from 1985-2019. Through comparative analysis of these exhibitions—Women of Sweetgrass, Cedar, and Sage (1985), Watchful Eyes (1994), Legacies (1995), Nourishing Hearts, Creative Hands (1998), and Hearts of Our People (2019)—this thesis identifies eight paradigmatic artists whose repeated inclusion across exhibitions constitutes canonical recognition: Kay WalkingStick, Jaune Quick-to-See Smith, Carm Little Turtle, Ramona Sakiestewa, Emmi Whitehorse, Jolene Rickard, Roxanne Swentzell, and Shelley Niro. Organized thematically around body and identity, land and place, memory and materials, and curation and exhibition space, this analysis demonstrates that the canon these artists represent differs fundamentally from its Western counterpart—constituting not a hierarchy of individual genius but a network of relational practices grounded in Indigenous knowledge systems and the ongoing assertion of cultural sovereignty.

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