Digital Commons Network^™

Correlations Between Social Media, Body Image Perceptions, And Disordered Eating Prevalence In Postpartum Women: A Pilot Cross-Sectional Study, Hannah Smith

Master's Theses

Postpartum women are a high-risk population for body dissatisfaction and disordered eating behavior due in part to the plethora of hormonal and physiological changes. Despite this, research examining this issue among postpartum women remains limited.

This pilot cross-sectional study investigated the relationship between social media use, body dissatisfaction, and disordered eating behavior among women up to 13 months postpartum. For this study, the following research questions were asked: Is high social media usage associated with higher levels of disordered eating among women up to 13 months postpartum? Is the association between social media usage and disordered eating mediated by a …

Subalpine And Alpine Plant Community Turnover In Yosemite National Park Following 30 Years Of Climate Warming, Rachel Friesen

Master's Theses

Subalpine and alpine regions in California are warming more rapidly than lower elevations. In response, high-elevation plants may acclimate or adapt to the new climate, move to higher elevations or latitudes, persist in refugia, or go extinct. While models predict substantial declines in subalpine and alpine plant communities due to discontinuous population distributions and lack of upslope area, actual responses may vary due to lags in dispersal, establishment, and extinction. Although shifts in high-elevation plant communities have been documented in other regions of the world, such changes have not yet been studied in Yosemite National Park. To assess high-elevation plant …

Assessment Of The Imx7ulp Heterogeneous Soc For Use In A Next Generation Student Cubesat Obc, Lorenzo A. Pedroza

Master's Theses

CubeSats represent a rapidly evolving platform for space research, industry, and education, demanding increasingly sophisticated onboard computing solutions that balance performance, fault tolerance, size, weight, and power constraints. Although the design of the Cal Poly's CubeSat Lab's (PolySat) current On-Board Computer (OBC) keeps up with many of these factors, the demands of modern workloads like fine attitude determination will start to outpace available compute. While the selection of a more capable processor to address this would have traditionally resulted in increased energy usage, modern system-on-chip (SoC) architectures offer novel ways to trade available compute for power savings on-the-fly. With this …

Development Of A Novel Bio-Mimetic Ornithopter With Variable Flapping Angle, Geourg Kivijian

Master's Theses

From the beginnings of flight, flapping-winged flight has been a goal of many engineers to mimic and replicate. With gains in aerodynamic efficiency of flight and certain other favorable characteristics such as reduced noise, higher maneuverability, and surveillance opportunities in urban environments, flapping-wing aerial vehicle(FWAV) designs are consistently pursued in many corners of academia and industry. This thesis goes into the development of a flapping wing aerial vehicle with a Bio-mimetic novel drive mechanism that is cable-driven and can produce variable amplitude and frequency flapping stroke. Employing a Field-Oriented Control (FOC) Brushless Direct Current (BLDC) motor, paired with a bio-mimetic …

A Fault-Tolerant, Multi-Heap Dynamic Memory Allocator For Freertos, Garrett E. O'Neill

Master's Theses

The use of dynamic memory allocation presents a significant challenge for embedded systems, particularly in applications that require high reliability. The software controlling these systems needs to perform critical operations within strict timing constraints, and memory management plays a critical role in a system’s ability to meet these constraints. Dynamic memory allocation is inherently non-deterministic: if a task requests memory, it is impossible to predict how long it will take for the memory to be allocated. If a critical task were to rely on dynamically allocated memory, its execution could become stalled leading to a missed deadline and system failure. …

Leveraging Machine-Learning Algorithms In Two Car Crash Detection Systems On A Custom Dataset, Addison Jacob Sandvik

Master's Theses

Traffic accidents pose a significant threat to public safety, causing millions of deaths and injuries worldwide each year. While efforts to reduce accidents have seen limited progress in recent years, improving emergency response times through automated detection systems is a promising avenue for saving lives. This thesis describes the development of machine learning-based traffic accident detection systems, exploring both video classification and image detection models. The models are trained on a new dataset deemed the Cal Poly Traffic Accident Dataset, an extension of the existing Car Accident Detection and Prediction (CADP) dataset with a precise collision annotations. Two systems were …

Design, Fabrication, And Testing Of A Dual-Rate Spring System For Mountain Bike Frames, Lucas P. Grizzle

Master's Theses

The design of full-suspension mountain bikes is a careful balance of suspension kinematics, structural dynamics, and manufacturing optimization for the expected use case. A bike designed to excel in one area will likely exhibit reduced performance in others. This optimization problem is addressed by designing, integrating, and testing a dual-rate spring system within a fully custom frame. The dual-rate spring is fully decoupled from the rest of the suspension kinematics, providing designers with an additional parameter to achieve ideal suspension behavior. This is accomplished by placing a thermoplastic polyurethane (TPU) bushing in series with the rear shock. The influence of …

Statistical Time-History Response Of Mid-Story Isolated Structures In Linearized Elastic Conditions, Min Thit Khant

Master's Theses

This study presents a statistical analysis of the seismic demand of mid-story isolated structures in linearized elastic conditions. The assumed earthquake database consists of 228 ground motions recorded in California from earthquakes with magnitudes greater than 6. A three-degree-of-freedom modeling approach is adopted, and the seismic demands of the substructure, superstructure, and isolation system are determined for varying isolated mass and stiffness ratios. The seismic demand of mid-story isolated structures at the isolation level is expressed in terms of the response of an idealized isolated superstructure supposed to be on the ground, while the demands on the substructure and superstructure …

Evaluating Nanobubble-Enriched Water Treatments For Cleaning Stainless Steel Winery Tanks At The Gallo Winery Research Station In Livingston, California, Edgar Godoy-Garcia

Master's Theses

ABSTRACT

Evaluating nanobubble-enriched water treatments for cleaning stainless steel winery tanks at the Gallo winery research station in Livingston, California.

Edgar A. Godoy-Garcia

Sanitation of stainless steel wine storage tanks is a critical component of quality control in commercial winemaking operations. Ineffective cleaning can lead to microbial contamination, product spoilage, and safety concerns. Traditionally, wineries rely on manual scrubbing, chemical cleaning agents, and extensive water rinsing cycles to maintain sanitary tank conditions. However, these methods are resource-intensive and may pose risks to both workers and the environment due to chemical exposure and wastewater generation. In response to growing industry interest …

Model-Based Design Of Compressed Lithium-Metal Pouch Cell Battery Modules For Evtol Applications, Scott J. Stirling

Master's Theses

Batteries with higher specific energy and power are essential for extending the range and performance of electric vertical takeoff and landing aircraft (eVTOLs). Anode-free lithium-metal pouch cells offer strong potential at the cell-level but require high compressive pressures to enhance cycle life and discharge performance. These pressures necessitate heavier structural components, reducing packaging efficiency at the module level.

To evaluate this tradeoff, a full-factorial enumeration model was developed to explore viable module designs within a constrained packaging volume. The model scales subsystem masses, enforces design rules and material limits, and accounts for large (~20%) cell thickness changes during cycling.

Results …

Thermal Modeling Techniques For Additively Manufactured Porous Metals, Lucas D. Rambo

Master's Theses

Advances in additive manufacturing have enabled the creation of metallic components with tailored porosity, offering design flexibility for thermal, structural, and fluid transport applications. This thesis investigates the effective thermal conductivity (ETC) of porous Inconel 625 (IN625) and Inconel-ceramic composites (IN625-RAM2) fabricated by Laser Powder Bed Fusion (LPBF) using Elementum 3D’s PermiAM technology. Experimental measurements of thermal conductivity using the laser flash method are compared to numerical models built from micro-computed tomography data. Simulations were performed using both finite element (FE) and finite volume (FV) methods to evaluate thermal transport in real microstructures. The study investigates the effects of micro- …

The Impact Of Accessibility Features On Player Experience In Video Games, Christine M. Widden

Master's Theses

While video game accessibility is a growing research topic, few studies investigate how players perceive the presence versus the absence of accessibility features, or how non-disabled players react to the option of accessibility features. This study explores these research gaps, investigating how access to accessibility features affects the experience of both disabled and non-disabled players. For the purposes of this study, a small platformer game was developed with as many accessibility features as feasible for the scope of the project. An A vs.\ B study was conducted in the game, with anonymous participants randomly assigned to version A, with all …

Nonlinear Integral Control Schemes For A Cadence-Heartrate Process: A Matlab Exploration, Alexander G. Elliott

Master's Theses

Keeping one’s heart-rate within a specific range during a cardiovascular workout can be difficult due to many factors including variations in the exercise environment and changes in energy level. One’s heart-rate can be controlled by tuning the intensity level of the activity over time. This study focuses on the relationship between a runner’s cadence and their heart-rate and explores ways to control the heart-rate by adjusting the cadence. Previous work in this area modeled the cadence-heartrate plant as a first-order linear system, but this has been shown to be insufficient. This work improves upon previous research in this area by …

Development Of A Reaction Wheel System For Cal Poly’S Spacecraft Attitude Dynamics Simulator, Caleb Nalley

Master's Theses

The Cal Poly Spacecraft Attitude Dynamics Simulator (SADS) is an ongoing project to develop a system capable of simulating the attitude dynamics and kinematics of a rigid body in space. Actuations on the SADS are performed by reaction wheels, however the current reaction wheels have various issues that decrease system performance and are not independent of the SADS. The reaction wheel developed as part of this thesis will be designed to improve performance and set out design specifications tailored to the SADS, serve as an independent assembly that can be transferred to other systems, and provide a general outline for …

Density-Dependent Habitat Selection And Home Range Sizes In A Recovering Population Of Island Foxes (Urocyon Littoralis) On Santa Rosa Island, California, Kathleen B. Elder

Master's Theses

Understanding factors that affect how animals select their home ranges is critical for proper species management, especially for threatened and endemic species. Density-dependent factors can be particularly difficult to understand because studying them requires large fluctuations in population size. The island fox (Urocyon littoralis), endemic to the California Channel Islands, has experienced dramatic fluctuations in population size making it an excellent candidate for studying the effects of density on home range size and habitat selection. In 2009, researchers on Santa Rosa Island took advantage of this “natural experiment” to document fox home ranges and habitat selection at a …

The Extraordinary In The Ordinary: Nineteenth Century Female Teachers And Their Professionalization Of An Occupation, Samantha G. Santana

Master's Theses

Women’s occupation as teachers has remained uncritically relegated to the sphere of women’s work. In reality however, early nineteenth century female teachers made clear articulations how they understood their occupations as teachers. Through their publications, autobiographies, and biographies written by former pupils, they left behind for current educators their estimations of the integral job they performed. As educators, these women maintained the paramount role of educating the nation’s next generation of citizens. This was of particular importance in the aftermath of the American Revolution when America’s children were subjected to lacking, colonial education experiments. Before and during the ensuing common …

Study On The Application Of Smart Electric Meters For Secondary Voltage Protection, Jayaditya Sisodia

Master's Theses

The purpose of our research is to utilize PG&E’s Smart Meters installed across California to protect the Secondary Voltage delivered to the meter. This means detecting electrical faults between the utility’s distribution transformer and the installed Smart Meter. Our goal is to propose and implement various solutions through additional devices and protocols to detect and prevent these faults, communicate them with the meter, and forward fault information to the utility. A device will be designed to be installed on the transformer, detect faults, shut off power transmission, and communicate to the meter via fiber optic cable. Research will then be …

From Conflict To Clarity: Resolving Differences In Habitat Assessments To Inform Conservation Priorities For The Giant Kangaroo Rat, Caroline Mackenzie

Master's Theses

From Conflict to Clarity: Resolving Data Differences in Habitat Assessments to Inform Conservation Priorities for the Giant Kangaroo Rat

Caroline MacKenzie

Conservation strategies frequently rely on habitat suitability models, habitat assessments and species occurrence data to identify areas for protection. However, these methods often produce conflicting inference on species presence and habitat quality, complicating management decisions. This study builds on prior work which used three distinct methods to guide conservation planning for the endangered Giant Kangaroo Rat (Dipodomys ingens): habitat suitability modeling based on abiotic predictors, aerial imagery to assess habitat quality through visible burrow mounds and live-trapping …

Multimodal Self-Folding Of Shape Memory Polymer Using Laser Induced Graphene, Liam Harrison Drew

Master's Theses

Shape memory polymers (SMPs) can undergo programmed shape transformations when heated above their glass transition temperature (T_g), enabling actuation through stimuli such as infrared (IR) radiation and Joule heating. These materials are promising for deployable systems and soft robotics due to their lightweight structure and elimination of traditional mechanical components. While IR-based actuation is simple and low-cost, it lacks precision in uncontrolled environments. Joule heating offers improved control but is often limited by conductive ink properties such as thickness, stiffness, or poor adhesion. This work introduces a novel method for multimodal SMP actuation using laser-induced graphene (LIG) transferred …

Effect Of Household Oil Contamination And Agricultural Soil Contamination On Phyllosilicate Nanocatalyst Performance During Pyrolysis Of Polyolefins, Joey Velasquez

Master's Theses

The effect of household oil and agricultural soil contamination on catalyst performance during polyolefin pyrolysis was simulated on mixed virgin plastic pellets by evaluating contamination influence on mixed plastic degradation temperatures. Three phyllosilicate nanocatalysts including Fulcat435, Fulcat22F and Y-Zeolite were evaluated in this work based on a literature review of catalyzed plastic pyrolysis and these catalysts’ ability to lower plastic decomposition temperature by 50 °C – 100 °C. These findings were confirmed in this research through thermogravimetric analysis of a polyolefin mixture and further developed in furnace experiments containing household oil and agricultural contamination. Household oil contamination deactivated each of …

Comparing Machine Learning Paired Optimization Strategies For Single-Component Waterborne Direct-To-Metal Coatings, Harvir S. Kalkat

Master's Theses

As R&D attempts to fine tune properties before production, the redesign and testing process can become highly iterative. The repetitive nature of formulating can be difficult to escape when relying on chemical intuition alone. To provide some guidance in this process, machine learning (ML) can leverage data from previous trials¹ to design suggestions for subsequent trials. Although ML capabilities have vastly expanded in the last few years, integration of ML into chemistry R&D and education has been slow. Unraveling the mystique of ML can help change what has been a slow embrace in the coatings industry. It is important …

Multibeam Communication With Digital Sparse Arrays, Tavita Dayton

Master's Theses

The thesis presents a novel approach to maximizing spectral efficiency by utilizing spatial spectrum sharing in digital sparse arrays through non-uniform element configurations. A genetic algorithm approach is developed to optimally place the array elements to achieve maximum beam orthogonality and isolation. The proposed method is compared against three different configurations, namely purely random, random with jitter, and the Van Der Corput sequence (a low-discrepancy sampling approach). Simulated results demonstrate that the genetic algorithm and jitter methods successfully meet design specifications for beam orthogonality, average interelement spacing, and computational time. At the same time, the random and Van Der Corput …

Open Source Asic Design Curriculum, Francisco Wilken

Master's Theses

The ever-growing importance of Application-Specific Integrated Circuits (ASICs) in a high-compute world necessitates that college graduates entering the workforce are well prepared to design them. This thesis details the design of novel ASIC curriculum, using open source tools to teach at the undergraduate level. By moving to a higher level of abstraction than classical transistor-focused coursework, chip design material can be made accessible earlier in an undergraduate degree. Additionally, open source tools provide a powerful, free, and portable platform for students to create their own designs, solving assignments focused on industry readiness. Finally, this thesis studies the results and challenges …

The Effect Of Dietary Strawberry Supplementation On Glycemic Control Factors In Overweight And Obese Postmenopausal Women With At-Risk Diabetes Mellitus Pathogenesis, Jennifer Herrera

Master's Theses

Glycemic control is directly related to type II diabetes mellitus (T2DM). As of 2023, 30.5 million Americans have T2DM, and this number only continues to increase exponentially across the world (“Facts & Figures,” n.d.). T2DM is only a precursor to fatal conditions including cardiovascular disease, the number one cause of death in the United States. Extensive research has revealed that strawberries, a high polyphenolic food, may pose positive effects on glycemic control biomarkers. This study aimed to investigate the effect of three servings of strawberries in the form of 39-g of freeze-dried strawberry powder (FDSP) for six weeks on glycemic …

Remote Monitoring And Control Of Protection Relays Via Programmable Logic Controller, Rio Mcgown-Kauffman

Master's Theses

The purpose of this study is to explore the ability of a programmable logic controller (PLC) to wirelessly monitor and control power protection relays. The technologies surrounding power protection and industrial automation are ever evolving and have developed significantly in recent history. Industrial power applications call for consistent condition monitoring and status updates for various high-importance components. The high-importance components have power protection schemes that are managed by digital relays to trip circuit breakers in fault or unsafe operating conditions. The smart relays have a wide range of capabilities, including communications. Cal Poly assembled a collection of relays from Schweitzer …

Birch With Tidyclust In R, Jacob Perez

Master's Theses

This thesis introduces a new implementation of the BIRCH clustering algorithm within the tidyclust framework in R. Traditional hierarchical clustering methods face scalability limitations with large datasets, due to their computational complexity. BIRCH offers a scalable alternative by summarizing data into microclusters using a CF-tree. This work shows the integration of the phases of the BIRCH algorithm into tidyclust, which enables a streamlined workflow for model specification, evaluation, and prediction. Through this implementation, scalable hierarchical clustering has been brought to R users within the tidyclust interface, enhacing the ability to better analyze large datasets.

Modeling Battery Energy Storage Systems To Study The Effects Of Battery Chemistry And Operation On Power Quality, Lin E. Knudsen

Master's Theses

This thesis studies the impacts of battery chemistry (specifically lithium-iron phosphate, sodium-ion, and solid-state), AC voltage, battery size, charging mode, state of charge (SOC), active power draw, and power factor on the power quality of a Battery Energy Storage System (BESS). For harmonic evaluation, the metrics provided by the IEEE Standard 519 are used as a guideline to quantify voltage and current harmonics. A comprehensive MATLAB Simulink using Simscape Electrical is used to develop and simulate the models for the battery, DC-DC converter, AC-DC converter, and the grid. A total of 57 simulation cases varying the BESS factors are performed, …

Hands-Free Balance Protocol And Development Of An Iphone App For Self-Assessment, Jacob Matties

Master's Theses

For many clinical populations, the measurement of balance is a critical task. Previous studies have agreed that smartphone IMUs provide a valid measure of balance that can be significantly correlated with force plate measurements and is sensitive enough to distinguish between various balance poses, but many balance assessment protocols require uncommon equipment or the use of hands during assessment. These limit accessibility of balance assessment. To eliminate the need for hands or any additional equipment, this study assessed the use of a smartphone recording the root mean square of 3D acceleration magnitude. The goal of the study was to determine …

Modeling And Efficiency Analysis Of Hybrid Ac/Dc And Conventional Ac House Electrical Systems For Net-Zero Energy Homes, Tyler Bury

Master's Theses

This thesis presents the design, simulation, and comparative efficiency analysis of hybrid AC/DC residential homes versus conventional AC homes for Net Zero Energy Homes (NZEH). Motivated by the increasing prevalence of DC-native technologies such as solar photovoltaics, battery storage, and DC-powered electronics, this work evaluates whether hybrid AC/DC distribution can offer measurable efficiency benefits over traditional systems. Twelve detailed house models were developed—six employing a hybrid AC/DC architecture and six based on conventional AC systems, each supplying a combination of AC and DC residential loads. Simulations were conducted using MATLAB/Simulink to model steady-state efficiency under various loading conditions. Grid configurations …

Determinants Of Integration: Migration Difficulty, Mental Health, And Social Connections Among Eritrean Immigrants, Shewit Woldemichael

Master's Theses

This thesis explores how the experience of migration hardship affects integration outcomes of Eritrean migrants in the U.S. and the Netherlands. Using original survey data and the Immigration Policy Lab’s Integration Index (IPL-24), this paper investigated the intersection of economic, psychological, and social interactions that facilitate integration outcomes. This research finds that migration hardship doesn’t just make people’s lives more difficult; it breaks down the social ties and mental well-being that are essential for economic success measured by integration.