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tBEARR - Tardigrade Bio-ExplorAtion Reproduction Research Satellite
No full textThe mission aims to launch four separate cultures of tardigrades aboard a 3U CubeSat to Low Earth Orbit to study the effects of UV and cosmic radiation on their genetics and cell composition, which may, in turn, affect their reproduction cycle.
• tBEARR is a 3U CubeSat mission under development by the Embry-Riddle Orbital Research Association (ERORA), an undergraduate research club at Embry-Riddle Aeronautical University in Daytona Beach, FL.
• Critical life support systems will be developed to maintain tardigrade viability as orbital experiments are being conducted.
• Tardigrades, in their cryptobiotic state, will be exposed to space radiation and later rehydrated in orbit to assess their reproductive viability post-exposure
Application of Particle Swarm Optimization for Tuning PI Controllers in CMG-Driven PMSM Systems
No full textThis work presents the application of an automated PI controller tuning method based on Particle Swarm Optimization (PSO) for Control Moment Gyroscope (CMG) systems. CMGs are critical components in aerospace systems, offering high-torque amplification and precise attitude control capabilities. Their superior performance compared to Reaction Wheels (RWs) makes them ideal for demanding applications such as spacecraft orientation and agile maneuvering. At the core of CMG operation are Permanent Magnet Synchronous Motors (PMSMs), which are typically controlled using Field-Oriented Control (FOC) for accurate response. FOC relies heavily on the performance of PI controllers within the current and speed control loops. Achieving optimal performance with conventional PI tuning methods such as Ziegler-Nichols, manual tweaking, or heuristic approaches has become increasingly challenging. Factors such as sensor noise, system nonlinearities, and hardware inconsistencies hinder their effectiveness and limit generalizability. These challenges often lead to suboptimal performance and production delays, as manual fine tuning remains a time-consuming process when high system efficiency is required
Development of a CubeSat-Sized Hybrid Chemical Propulsion System for In-Orbit Demonstration
No full textLetara Ltd. is a company based in Hokkaido, Japan, specializing in in-space hybrid chemical propulsion systems. Letara has been actively researching CubeSat-sized hybrid chemical thrusters with a focus on fuel optimization and improved scalability for small satellite applications.
The first project is based on a 2U-sized thruster with the aim to demonstrate a safe, sustainable, and scalable miniaturized hybrid propulsion system in orbit. The technology demonstration is scheduled for 2026
Hardware in the Loop Simulation for Commercial Off the Shelf Sensor Qualification in Small Satellite Rendezvous and Proximity Operations
No full textThis paper presents a hardware-in-the-loop (HIL) simulation framework designed for the rapid evaluation and qualification of commercial off-the-shelf (COTS) sensors in small satellite Rendezvous and Proximity Operations (RPO). The proposed system supports 2U to 6U CubeSat platforms and enables subsystem-level testing by integrating a real-time mechanical simulator with a software-defined dynamic environment. The setup replicates target satellite motion using a custom 3-DOF rig driven by stepper motors and supports configurable sensor parameters, motion profiles, and automated parameter sweeps. A Microsoft Kinect v2 sensor captures RGB, IR, and depth data, enabling multi-spectral evaluation under varied illumination and material reflectivity conditions. Preliminary results demonstrate successful closed-loop estimation of satellite attitude using edge-based pose tracking. Compared to traditional RPO testbeds such as air-bearing platforms, this low-cost, modular framework reduces development time, eliminates the need for high-fidelity digital twins, and supports rapid testing of vision-based navigation algorithms. The architecture also enables scalable training data generation for machine learning-based systems and supports future enhancements, including automated center-of-gravity adjustments and dynamic sensor positioning
Optimal Distributed Energy Resource Control and Scheduling in a Microgrid Framework
No full textAs we use more renewable energy, such as solar power, and add new devices, such as electric vehicle chargers and battery storage, to our buildings, the management of electricity becomes more complex. These local energy sources and devices can form small microgrids that need careful coordination to work efficiently with the main power grid. The system figures out the best times to use, store or charge different devices (such as batteries and EVs) to avoid costly, high electricity demand spikes and help stabilize the main power grid, especially when asked by the utility company. A major part of this work involved creating better ways to control building heating and cooling (HVAC) systems, which are big energy users. Two methods were developed: one learns from past energy use data to predict how temperature settings affect energy consumption, and another uses simplified physics models to understand how heat moves in a building. By intelligently scheduling all of these devices together, our aim is to make our energy use cheaper, more reliable, and better integrated with renewable resources
Evaluating Uplift at the Leading Edge of the Yellowstone Hotspot - A Study of the Shoshone River Drainage
No full textThe stationary mantle plume (or hotspot) underlying the Yellowstone region has caused parts of the surrounding landscape to rise as the continental plate migrates over it. However, scientists do not fully agree on the spatial pattern of this uplift and few measurements of the landscape have been made to provide estimates of uplift rates. To better understand uplift patterns and rates, this study examines the Shoshone River, which flows across the predicted zone of highest uplift at the northeastern, leading edge of the hotspot. Digital-terrain analysis is used to measure channel steepness and field and imagery approaches are used to study the position of river terraces – planar landforms underlain by river deposits indicating the river and valley-bottom position in the past. Numerical dating of the terrace deposits enables calculation of how fast the river has cut down into the landscape over the last 350 thousand years, and this incision is assumed to reflect the pattern of uplift. Incision rates in the study area appear to be increasing over the past ~350,000 years, and the zone of fastest uplift does not coincide with the high terrain near Yellowstone; instead it occurs at the western edge of the Bighorn Basin where the continental plate is just starting to move over the hotspot. This study provides the first ages of these terraces and clear evidence that the fastest uplift associated with the Yellowstone hotspot is happening farther east than some workers previously thought
An Embodied Social Demography for Trans and Nonbinary Workers
No full textRecently, the separation of “sex” and “gender” has seen intense debate in public discourse, stemming from skepticism about the social sciences and the measurement and study of gender specifically. Meanwhile, the United States population is becoming more gender diverse, with roughly 1 in 200 people now identifying as trans gender or gender nonbinary (that is, as a gender that is different from that person’s sex assigned-at-birth or outside of the sex-gender binary). This growing population experiences numerous disadvantages across social life, including obstacles in one particularly important aspect of the American Dream: the right to have and hold a job.
I use this dissertation to study how the norms and practices that undergird a rigid sex-gender binary affect the employment of trans and nonbinary people. To do so, I use statistical tests from a large survey and a close reading of workplace narratives from about 1000 trans and nonbinary people. Drawing on these data, I make three points.
First, I illustrate how detailed measures of gender identity and expression help us understand the employment outcomes for large and diverse groups of people. That is, viewing the population as a collection of “males” and “females” is not enough to understand real trends given that social treatment is highly dependent upon how masculinity and feminity are actually expressed. Second, I show why social scientists should study workplaces to understand inequality thoroughly because these organizations circulate income, status, and other resources according to the detailed expression of individuals’ social identity. Third, I publicize how several kinds of friction related to employment are associated with harm to trans and nonbinary people’s health. Together, this dissertation illustrates how ideas about sex and gender create an environment that is extremely taxing and difficult for trans and nonbinary people to navigate, a takeaway relevant to numerous kinds of social oppression as well as access to other institutions, such as education, medical care, and more. I discuss ways of reducing workplace friction both from inside and outside of organizations, making the case to pay more attention to fined-grained aspects of gender and other social identities, not less
An Investigation Into the Principle of Symmetric Criticality
No full textIn physics, symmetries help us understand complex systems by revealing conserved quantities and simplifying equations. In the context of general relativity, where spacetime is curved and dynamic, these symmetries become especially important when trying to reduce or solve the equations that govern gravitational and matter fields.
This dissertation investigates a mathematical principle known as the Principle of Symmetric Criticality (PSC), which helps determine when symmetries can be used to simplify physical theories without losing essential information. While often assumed to be valid, PSC does not always hold, and understanding when it does is critical for the reliable use of symmetry in theoretical physics.
The first part of this work identifies all possible spacetime symmetries that allow such simplification for gravitational fields, specifically within Einstein’s theory. The second part introduces a new method for choosing coordinate conditions, or “gauge fixing,” when working with simplified versions of the equations. An important step for both theoretical understanding and computational modeling. Finally, the third part extends these ideas to spinor fields, which describe particles like electrons and are essential in quantum field theory. This extension uses a two-component spinor formalism adapted to curved spacetime, showing that the same symmetry criteria used for gravitational fields also apply to spinor fields.
To support these results, custom computer code was written to automate the complex symbolic calculations involved. Together, the findings offer new tools and insights for researchers studying symmetry, gravity, and the mathematical foundations of field theory
Enabling Sustainability Transitions for Great Salt Lake: Framing of Public Opinion, Boundary Work, And Policy
No full textThis dissertation explores how people think about, talk about, and take action to save Great Salt Lake, which reached historic low levels in 2021. Using surveys, public records, and legislative documents primarily from 2022 to 2024, the research examines public opinions, collaborative efforts, and policy changes related to the lake. The first chapter looks at what people value about the lake and what actions they want to see taken. It finds that people are very concerned and want significant efforts to stop the lake\u27s decline. The second chapter investigates how different groups work together publicly to negotiate new understandings, create unified messages, and drive change toward a more sustainable future for the lake. It identifies key activities and objects that help bridge diverse perspectives. The third chapter analyzes legislation and public comments to understand how different values and ways of thinking have influenced policy decisions regarding Great Salt Lake. The findings show that expanding the diversity of perspectives has helped create conditions for legislative support. This research provides valuable insights into how communities can come together to protect vital natural resources. By examining the interplay between public opinion, collaborative boundary work, and legislative actions, this dissertation highlights the importance of integrated approaches to fostering sustainability transitions and offers practical recommendations for other regions facing similar environmental challenges
Cutting Propagation and Out-Planting of White-Margined Beardtongue (\u3ci\u3ePenstemon albomarginatus\u3c/i\u3e M.E. Jones), A Vulnerable Herbaceous Perennial of the Mojave Desert)
Get PDFPlant biodiversity is crucial for the proper functioning of ecosystems, with many species needed to maintain the variety of functions provided, especially with increasing environmental change. However, plant biodiversity is threatened in many different ecosystems, primarily through habitat loss. Species can be conserved by protecting their original habitat and mitigating for threats such as invasive species or altered disturbance regimes (plant conservation); however, with declining population numbers and continued habitat loss and/or disturbance, it may be necessary to actively move plants (plant restoration). Plant restoration is dependent on developing the capacity to a) reliably propagate plants in a nursery and b) effectively establish these plants on the landscape to either create new populations in suitable habitat or supplement existing populations. To inform management efforts, we researched different propagation and out- planting methods for a vulnerable species in the Mojave Desert, USA: white-margined beardtongue (Penstemon albomarginatus M. E. Jones). We successfully propagated the species using stem cuttings and refined this process. We characterized habitat across the species’ range of P. albomarginatusand found that mature plants were more associated with interspaces and strongly avoided shrub canopy cover. We conducted the two following out-planting trials for the species: 1) determined a lower level of watering (1.9 L/plant every two weeks for eight weeks) that supported plant establishment and 2) tested planting into different landscape microsites to see if microhabitat affected plant establishment. Data from the first growing season of the latter out-planting trial suggest that interspace gaps between perennial plants are the best out-planting microsites for this species, although long-term monitoring is still needed. In both of our planting trials, we achieved relatively high establishment in suitable habitat outside of the species’ current range, which holds promise for potential management efforts to create new populations in suitable areas. Our findings are helpful guidelines that can be referenced by restoration practitioners developing restoration plans for P. albomarginatus