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Stability Insights from Modeling Chronic Myelogenous Leukemia
Get PDFThis thesis centers around a model for chronic myelogenous leukemia (CML) as it behaves under imatinib treatment, a common medication for CML patients, and the anti-leukemia immune response. The dynamics are represented with a system of nonlinear delay-differential equations first constructed by Kim et al. in 2008, capturing population changes of T-cells and various CML growth stages. We investigate stability in both the clinical and mathematical sense. Through numerical simulations, we computationally incorporate a supplementary treatment plan to determine its effectiveness in aiding immune response and medication in achieving remission and full elimination. The primary goal is to conduct a stability analysis of the system. We derive two steady states, one for a cancer-free environment and one for CML persistence in the presence of T-cells. Through linearizing the system with Jacobian matrices with respect to non-delayed and delayed state variables, we seek parameter restrictions toward negative eigenvalues (or those with negative real part), and hence asymptotic stability
The Impact of Brand Ownership Structure on Favorability and Authenticity Perception of Surf Athlete Sponsorships
Get PDFThis study investigates whether the ownership form of a surf brand, i.e., public or private, affects consumer authenticity and brand favorability impressions when partnered with surf athletes. Following Aaker\u27s Brand Equity Model and relevant literature on influencer marketing and subcultural branding, the study employs a mixed-methods approach with a structured questionnaire survey (n = 526) alongside qualitative analysis of open-ended responses. Quantitative results indicate minimal variation in mean brand favorability for public compared to private brands, while privately owned brands had more consistent perceptions of authenticity across combinations of athlete partnerships. Qualitative outcomes support the assumption that privately owned brands were perceived as part of community activities, culturally aligned, and not mass commercialized. Public brands may, however, be perceived as a larger part of surfing culture but less connected to core surf values. These results suggest that authenticity and alignment with surf culture remain central drivers for sponsorship success, with private ownership at least theoretically offering advantages in terms of subcultural credibility
Using Hydrologic and Hydraulic Simulations to Predict Near-term Effects of Beaver Habitat Restoration on Flood Flows
Get PDFThere is a growing need to predict the complex hydrologic and hydraulic effects of beaver-maintained wetlands. This study uses relatively simple inputs and a replicable methodology to predict flood flow impacts of beaver habitat restoration at the site design scale using the engineering industry’s customary hydrology and hydraulic modeling approach. This study focuses on Toro Creek, the primary drainage for a 15.2 square mile watershed on the California Central Coast.
A hydrologic model of Toro Creek watershed was developed in HEC-HMS to approximate saturated soil conditions typical of late-spring flooding events observed in the region. The hydrologic model was calibrated to an observed runoff event on February 19th, 2024, using stage, flow, and rainfall data collected during the 2023-2024 water year and PRISM 1991-2020 annual normal precipitation data to estimate rainfall distribution patterns throughout the watershed. Two-dimensional hydraulic models of baseline conditions and a near-term beaver habitat restoration scenario were developed in HEC-RAS. These models were used to simulate observed, historical, and synthetic storm events. The historical storm events – January 9th and March 10th, 2023 – had estimated peak flows of 4722 cfs and 4738 cfs, respectively. The 100-year and 500-year estimated return interval storms were based on NOAA Atlas 14 rainfall estimates and had estimated peak flows of 7125 cfs and 9299 cfs, respectively.
Modeled beaver habitat with 8 dams over a 2.2km reach showed a small but significant peak flow attenuation (\u3c 1%) and increase in lag time (7 minutes on average) relative to baseline conditions for storms smaller than an approximately 25-year event with effects diminishing for larger storms. The scale of modeled attenuation does not suggest that beaver reintroduction alone would be an effective flood control measure for Toro Creek. The scale of attenuation from modeling physical obstructions was similar to the scale of effects expected from flow through dam faces, hyporheic flow, and geomorphologic changes, suggesting that these factors will be necessary considerations to develop this modeling approach into a practicable methodology in industry
Balance Assessment of Disc Golf Players by a Smartphone
Get PDFDisc golf is an underrepresented sport in biomechanics research, even though it could have effects on gait and balance. Forward and side lunges performed while throwing discs can improve static and dynamic balance. The purpose of this study was to explore the effects of playing disc golf on various static and dynamic balance metrics. Static and dynamic balance experiments were done on 20 disc golf players and 20 control participants to record their RMS of acceleration during the double leg, tandem, and single leg static poses, as well as their gait speed, cadence, stride length, right step length, left step length, and step width during gait. Static data were collected using the acceleration of a handheld smartphone using the MATLAB app, and dynamic data were collected with the smartphone in the participant’s pocket using the OneStep app. The results of the disc golf players were compared against those of the control group using t-tests and regression analyses. It was found that (1) the disc golf players had improved gait speed, stride length, right step length, and left step length, and (2) after accounting for age, it was found that older age was correlated with worse tandem balance. The findings showed that playing disc golf can improve dynamic balance, but not necessarily static balance
Torsional Vibration Kit Simulator (TKS)
Get PDFThe goal of this project was to create torsional vibration on a shaft while limiting axial and radial vibration. To do this an eddy current brake was used to slow down a rotating shaft. The electromagnets used to create the eddy currents are able to be turned on and off at a frequency produced by a function generator. This power cycling of the electromagnets creates an alternating braking force thereby inducing torsional vibration while limiting the other two vibration type
Brush Seal Cycling Test Rig
Get PDFTo prevent backflow from the high pressure compressor stages of their gas turbines to lower pressure regions, Solar Turbines utilizes brush seals along their driveshafts. Due to manufacturing limitations, no shaft is perfectly symmetric about its rotating axis, leading to orbiting that creates asymmetric friction on the shaft through rubbing. With this biased application of friction comes a hotspot on one side of the shaft, causing bowing of the shaft and cascading into an amplified vibrational response. Our goal is to gather data on this phenomenon and offer a potential solution
Air to Water Capture in Support of UN Sustainable Development Goals
Get PDFThis senior project explored the use of thermoelectric cooling for atmospheric water capture. The system was designed to cool aluminum condensing surfaces below the dew point using Peltier modules, with forced convection heat sinks on the hot side. The purpose of this system was to gather reliable amounts of water for various water-scarce areas around the world to help meet the UN\u27s sixth Sustainable Development Goal.
The final design of this project consisted of a 1.5 x 1.5 x 2 foot frame made of acrylic panels and insulation. Within the frame, the thermoelectric system was constructed using Peltier modules with heat sinks on one side to dissipate the heat produced in the system and condensing arrays on the other side for water to condense on. Fans were also installed in the system to cool the hot side of the Peltier devices and to bring air into the system. The system runs on grid power.
While early designs prioritized large cold-side fin arrays for surface area, thermal analysis revealed that excessive thermal mass prevented surfaces from cooling quickly enough for condensation. A detailed energy model, supported by experimental testing, showed that most of the Peltier devices\u27 cooling capacity was spent lowering the block temperature, not extracting moisture. On the hot side, fan-driven convection was evaluated using Reynolds and Nusselt-based modeling. Although theoretically adequate, real-world inefficiencies limited performance. The project provides key design insights for improving thermoelectric water capture systems
Custom Low-Profile Vacuum Valve
Get PDFIn Autometrix’s proprietary gantry style cutting table, a vacuum pulled through a channel array creates suction to hold soft materials firmly in place. To provide modularity for their customers a unique valve must be designed to segment the transverse channels in two or more sections. The solution must use minimal fasteners, maximize longevity, prove affordable, and be easily manufacturable
Sorting Recycling with Neural Networks
No full textRecycling has many significant environmental, social, and economic benefits. The goal of this project is to identify different classes of materials for recycling, such as Cardboard, Glass, Metal, Paper, Plastic, and Trash. Three different deep learning models are used, including a 4-layer CNN (Convolutional Neural Network), VGG (Visual Geometry Group) 16, and YOLO (You Only Look Once) v11. Computer simulation results show that YOLO v11 performs the best, with an accuracy of 93.2% on trashnet database