Digital Commons Network^™

Effects Of Irrigation And Nitrogen Management On Yield And Leaching Risk In Organic And Conventional Broccoli Fields, Shane Egerstrom

Master's Theses

Under regulatory pressures to reduce groundwater contamination by nitrate from fertilizer, such as those posed by the Central Coast Regional Water Quality Control Board’s Agricultural Order 4.0, a need exists to better understand interactions between irrigation and nitrogen (N) management. To increase N use efficiency (NUE), growers are encouraged to account for additional sources of N in their management plans, such as irrigation water N and preplant soil N. The availability of these N sources for plant uptake and how it is affected by other management conditions is not yet well documented. We conducted 6 field trials, 3 organic and …

An Evaluation Of Road Network Structure As A Predictor Of Traffic Volume, Colin M. Mcdonald

Master's Theses

This thesis evaluates the relationships between various graph theory metrics and taxi traffic volume for the cities of San Francisco, California and Porto, Portugal. We also evaluate a modified betweenness centrality metric which incorporates the count of distinct origin-destination pairs from the taxi data as the weight function. This thesis extends a paper by Pengyao Ye, Bo Wu, and Wenbo Fan by reducing circularity through a temporal train-test split and by comparing both line-graph and primal-graph formulations of betweenness centrality.

We found that past traffic volume is almost perfectly correlated with future traffic volume and that the modified betweenness centrality …

Sustainable Management Of Soilborne Pathogens In Strawberry Production Through Host Resistance And Sanitation Practices, Maria G. Alvarez Arredondo

Master's Theses

Strawberry production in California is significantly impacted by soilborne pathogens that reduce plant productivity and increase management costs. This research addressed management of these pathogens through two independent approaches: evaluation of host resistance in strawberry cultivars and assessment of sanitation practices for reducing pathogen movement between fields.

Macrophomina root rot, caused by Macrophomina phaseolina, was evaluated over two growing seasons (2024–2025 and 2025–2026) using field trials at California Polytechnic State University, San Luis Obispo. In Year 1, disease incidence varied widely among genotypes, with mortality ranging from 1.3% to 88.8% and an average mortality of 26.4%. Area under the …

Evaluation Of Alternative Solvents For Electrospinning Occluded Scaffolds To Model Intracranial Atherosclerotic Disease In Blood Vessel Mimics, Olivia D. Rankin

Master's Theses

Intracranial atherosclerotic disease (ICAD) is characterized by a buildup of fatty plaque within the walls of arteries supplying the brain, resulting in vessel narrowing, restricted blood flow, and increased risk of ischemic stroke. While various treatments exist for ICAD, most are accompanied by high recurrent stroke rates and other adverse events, highlighting the need for further investigation and models for pre-clinical testing. Tissue engineered Blood Vessel Mimics (BVMs), consisting of a polymer scaffold sodded with human vascular cells, serve as physiologically relevant in vitro models for vascular device testing. This thesis focused on the application of alternative solvents to a …

Electrically Evoked Emg Decomposition Using The Perturbative Generalized Series Expansion, William R. Walker

Master's Theses

Electrically evoked electromyography records the muscle's response to nerve stimulation and has been used for clinical assessment of neuromuscular function, as well as treatments such as functional electrical stimulation or stroke rehabilitation. In every muscular contraction, an electrical signal is generated. These signals come from the summation of simultaneously recruited motor units, enabling decomposition techniques to reveal information about motor unit recruitment.  By improving the ability to decompose and analyze these signals, clinical treatments involving neuromuscular electrical stimulation can be optimized and better understood. Much of the research on EMG analysis focuses on voluntary EMG, leaving a gap in the …

Pcb Design For Place Cells Vlsi Chip, Gavin Reaksecker, Alex Krier, Joshua Lin

Electrical Engineering

This project presents the design and implementation of a 2 layer test-bench printed circuit board (PCB) for evaluating the functionality of a custom 40-pin VLSI integrated circuit. The objective is to create a reliable and portable platform capable of supplying configurable bias voltages, generating variable input signals, and monitoring both analog and digital outputs. The board integrates adjustable bias networks using potentiometers, digital and analog buffering stages, and optional battery supply operation. The VLSI device under test is mounted in dual-in-line (DIP) sockets to enable rapid replacement and repeated characterization. Dedicated test points are incorporated throughout the PCB to facilitate …

Chemical And Sensory Consequences Of Oxidative And Reductive Handling Of White Wines, Amelia Pargellis

Master's Theses

In the 2024 and 2025 vintage four experiments were performed each with a different varietal, namely Albariño, Grenache blanc, Loureiro, and Vermentino. These experiments investigated the effects of hyperoxygenation, reductive winemaking techniques, while monitoring the oxidation-reduction potential.

Albariño grapes were made following two juice protocols, control/reductive (Reductive Control) and oxidative (HyOx). Reductive Control received antioxidants (50 ppm SO₂, 160 mg/L ascorbic acid) and CO₂ blanketing, and HyOx underwent hyperoxygenation at approximately 700 mL/L/h of air for two hours through a stainless-steel sparging stone with 10-µm pores. Juice was cold-settled and racked. Reductive Control juice was split into …

Thermosiphon Lab Experiment, Ella C. Perry, Zach Barry, Madison K. Felton, Lane A. Hunter

Mechanical Engineering

The Cal Poly Mechanical Engineering Department aims to develop a new lab centered on a thermosiphon solar system. This lab will introduce the operating principles of thermosiphons while integrating concepts from heat transfer, fluid dynamics, and thermodynamics. A thermosiphon functions by heating water using thermal energy. The lab will examine the efficiency of this energy transfer. The final lab will be tailored to enhance student learning while ensuring ease of use for the Mechanical Engineering Department.

Hydropower Collegiate Competition 2026, Andres R. Arreola, Sammy D. Taporco, Kathryn E. Tinney, Ahmer S. Dhillon

Mechanical Engineering

The Hydropower Collegiate Competition (HCC) is sponsored by the Department of Energy’s (DOE) Water Power Technologies Office (WPTO) and is meant to offer university students an opportunity to solve complex hydropower challenges, build industry connections, explore career connections, and obtain a greater knowledge of hydropower’s potential in the United States. For this year’s competition, our team investigated a potential in-conduit hydropower site in California. Our work included creating a design package for a crossflow turbine related to our selected site and completing the community connections challenge. We also completed a siting and design report, community connections report, design and siting …

A Polygon Approach For Satellite Coverage Computation Problems, Caleb I. Arbreton

Master's Theses

During celestial body observation mission planning, predicted sensor coverage is a key analysis tool used by designers to inform concept of operations. It enables trade studies by applying a metric to assess how well different sensor, satellite, and constellation configurations can observe a mission's region of interest. The effectiveness of the studied components is then paramount in determining whether they are justified in the system architecture. Coverage computation becomes more difficult as sensor types and regions of interest (RoIs) deviate from simple shapes, and as problem formulations seek higher-fidelity results. These simplifications include: conical camera sensors, RoIs represented as simple, …

Object Detection And Classification For Man-Made Structures To Aid In Search And Rescue (Sar), Mio A. Nakagawa

Master's Theses

This project explores the use of various object detection and classification models to identify permanent man-made structures, specifically cell towers, water towers, watch towers as well as its corresponding shadows (attributes), from aerial imagery. The goal is to evaluate those models and test the feasibility of current models to detect man-made structures in aerial images, in an effort to support search and rescue operations as well as update network infrastructure databases. Multiple object detection models, as well as classification models, including YOLOv8 and VGG19 are implemented and trained on annotated aerial images to determine the presence or absence of man-made …

Empirical Comparsion Of Traveling Salesperson Approximation Algorithms, Shayan Daijavad

Master's Theses

The traveling salesperson problem deals with optimizing the route a traveling sales- person might take to visit a set of places exactly once and return back to their starting point. The problem is NP-hard, and it is hard to approximate in general, but special cases have many approximation algorithms, which come with tradeoffs. In this thesis we compare the runtime, approximation ratio, and overall implementation complexity of two approximation algorithms for the Euclidean version of the problem, a classical 2-approximation algorithm and the multifragment heuristic. We run both algorithms on randomly generated point sets and real world data from TSPLIB. …

Assessing Nitrogen Leaching Risk In Organic Vegetable Production, Megan Widle

Master's Theses

Nitrogen (N) leaching is the primary driver of groundwater contamination in agricultural regions. On California’s Central Coast, Agricultural Order 4.0 regulates this risk by constraining field-level N balances (N applied minus N removed). However, the assumption that unrecovered N is lost via leaching may not hold in organic and regenerative systems that promote soil organic matter accumulation. This study evaluated whether measured N leaching aligns with estimates derived from partial N budgets in organic systems, and whether management practices (intercrops, cover crops, and reduced tillage) can mitigate leaching risk. Four field trials were conducted to investigate N dynamics in organic …

Evaluating The Commercial Aquaculture Potential Of The Native Pacific Littleneck Clam (Leukoma Staminea) As A Climate Resilient Alternative To The Non-Native Manila Littleneck Clam (Ruditapes Philippinarum)., Skylar M. Wuelfing

Master's Theses

The California shellfish industry’s near-exclusive reliance on the non-native Manila littleneck clam (Ruditapes philippinarum) creates an economic vulnerability to climate-driven disturbances, which can cause mortality events that eradicate up to 80% of stocks. This singular reliance on an introduced species highlights a need for the evaluation of native alternatives like the Pacific littleneck clam (Leukoma staminea). Our goal was to assess the feasibility of using the native Pacific littleneck in commercial aquaculture by comparing their performance to the non-native Manila littlenecks across the following conditions: 1) a five-month field outplant trial at high and low intertidal …

Synthesis And Characterization Of A Graphene Oxide-Zif-8 Composite For Enhanced Post-Combustion Carbon Capture, Sydney Cooper

Master's Theses

Carbon dioxide (CO₂) emissions from fossil fuel combustion are a major contributor to climate change and its associated environmental impacts. The current standard technology for post-combustion carbon capture, aqueous amine scrubbing, is effective but requires significant regeneration energy and has high operational costs. As a result, solid sorbents have been investigated as lower-energy alternatives. Metal-organic frameworks (MOFs) are a promising class of porous nanomaterials due to their high surface area, tunable pore structures, and adjustable surface chemistry. Among them, zeolitic imidazolate framework-8 (ZIF-8) has high thermal and chemical stability, hydrophobicity, and favorable adsorption properties. However, conventional synthesis methods often rely …

Xenaforms: Reinforcing Kinematic Stability Through Rigid Connections, Katherine G. Thies

Architectural Engineering

XenaForms combine rigid planes and straight lines with the fluidity of structural origami to create beautiful, organic folded plate structures. Unlike many conventional structures, folded plate systems derive their stability from the interaction between connected panels, creating the appearance of a single continuous sheet of material. The XenaForm uses structural origami and triangulation to create stable points at the apex of two non-colinear triangles. While it is mathematically true that no moment needs to be transferred across the seam between panels in order to have a stable structure, allowing some moment capacity greatly helps during construction. Specifically, these stiff connections …

Microbial Literacy, Equity, And Sustainability At Cal Poly: A Policy Framework With University Housing As A Pilot Case, Joseph B. Fewel

Biological Sciences

Microorganisms play a fundamental role in human health, environmental systems, and the functioning of built environments, yet they remain largely absent from sustainability and public policy discussions. This project proposes a framework for integrating microbial literacy, equity, and health into institutional decision-making, using California Polytechnic State University (Cal Poly) as a case study and university housing as a pilot site for implementation. Drawing on interdisciplinary literature in microbiology, public health, environmental justice, and sustainability, as well as policy analysis and stakeholder interviews, this project examines how campus systems, including housing, ventilation, sanitation, food systems, and waste management, shape microbial exposure …

Elastic Actuator For Robotic Leg, Bruce Berg, Allan Pham, Madeline Slater, Sofie Zalatimo

Mechanical Engineering

The Cal Poly Legged Robots Group (CPLRG) is developing a 12 degree of freedom robot with the goal of eventually performing highly dynamic movements such as jumps and flips. During such movements, large impact forces will be experienced by the leg, potentially resulting in damage to physical components such as the motors. The scope of this project is to integrate elastic elements into the quadruped legs to reduce shock loads on the motors and improve the efficiency of the legs through energy storage. The key stakeholders for this project are Professor Charlie Refvem and Dr. Simon Xing. Other stakeholders include …

Computational Modeling To Evaluate Bipolar Flexible Electrode Designs For Use In Sciatic Nerve Stimulation, Krystyna S. Allman

Master's Theses

Peripheral nerve stimulation is clinically used to manage pain, rehabilitate motor function, and promote nerve regeneration. The sciatic nerve is often studied for stimulation due to its accessibility and clinical relevance. A conventional nerve cuff electrode is the least invasive method for nerve stimulation, but the mismatch of mechanical properties of the electrode with the nerve tissue can cause damage to the nerve and the electrode itself. This study investigated a novel bipolar, gold nanowire-based cuff electrode design and its ability to selectively activate fibers in the rat sciatic nerve at varying interelectrode spacings. In COMSOL, A finite element model …

Skip The Grid: Bringing Solar Energy To The Navajo Nation, Makaela L. Zavala

Construction Management

Skip the Grid is an interdisciplinary service project in which California Polytechnic State University (Cal Poly) students partner with Heart of America and SOLV Energy to install off-grid solar systems for families in the Navajo Nation and Hopi Reservation. The project aims to address energy inequity by providing reliable electricity for lighting, refrigeration, and essential daily needs. This paper focuses on the communications and logistics planning required to support a large-scale service project involving over twenty students and multiple partner organizations. The methodology included coordinating travel, organizing team assignments, managing documentation, and maintaining communication throughout the trip. The project resulted …

Design And Characterization Of A Pulsed Electric Field Chamber For Microalgae Lysis, Connor Strutin

Electrical Engineering

Microalgae are a promising renewable source of biofuel due to their high lipid content and rapid growth rates; however, algae cells must be electroporated (lysed) to release these lipids. The system developed in this project applies short (40 μs–10 ms), high-intensity (up to 33 kV/cm) pulsed electric fields (PEF) across cell membranes to enable electroporation.

Our lab-scale PEF chamber generates uniform, high-intensity electric fields using parallel-plate electrodes with sub-millimeter spacing. The system is designed to efficiently lyse microalgae cells for lipid extraction and biofuel production.

Contributor Bios, Editorial Board

Intertidal

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Rooted, Amelia Flint

Intertidal

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Test Bench Pcb Design For A Vlsi Grid Cell Chip, Nicholas Bruk, Jason Alexandar

Electrical Engineering

This report presents the design, implementation, and validation of a custom printed circuit board (PCB) test bench for a VLSI grid cell emulation chip. The final board provides two independently adjustable 5V supplies using LM317 linear regulators, eleven potentiometer-controlled bias voltages, high-impedance buffering of analog outputs via an MCP6022 dual operational amplifier, and buffering of digital outputs using a 74HC244 buffer IC. The design includes a 40-pin DIP socket for the VLSI chip, extensive test-point headers for probing, and a 9V battery input for portable operation. Five fully functional boards were fabricated using ExpressPCB and assembled with through-hole components. An …

Design And Parametric Testing Of A Transimpedance Amplifier For Low-Power Biomedical Applications, Stanlon Tan, William Chung, Brandon Wu

Electrical Engineering

This project developed and evaluated an optical sensing system for detecting changes associated with glucose concentration. The system combined a laser-diode, cuvette sample holder, photodiode, resistive-feedback transimpedance amplifier, high-resolution analog-to-digital converter, and microcontroller. Parametric testing evaluated the effects of input current and feedback resistance on transimpedance gain, output range, and linearity. Firmware was developed to configure the ADC, average repeated conversions, monitor measurement variation, convert raw digital counts into voltage using a source-meter calibration equation, and compare sample measurements with a water reference. A cuvette enclosure maintained alignment between the laser-diode, sample, and photodiode while reducing external optical interference. Testing …

Simulation Of Silicon Neurons With Memristive Synapses For Ai Accelerators, Marcus Ivey, Kelvin Shi

Electrical Engineering

This project seeks to design and simulate a neuromorphic spiking neural network (SNN) that implements the logical AND and logical OR operation through the interaction of a Leaky Integrate-and-Fire (LIF) output neuron and memristive synapses modeled using the Biolek formulation. Two pulsed inputs are transmitted through memristive devices whose conductance serves as the synaptic weights. A supervised Hebbian training strategy, implemented in MATLAB, is employed to adjust the synaptic conductance according to the Hebbian delta rule. The proposed framework demonstrates how elementary logical computation may arise from biologically motivated learning processes embedded in hardware-realistic neuromorphic circuits. The study provides a …

Ugv-Based Vertebrate Pest Deterrence In Vineyards: Vision-Guided Row Patrol And Navigation, Candace Qualls, Karina Wilson, Ben Badhorn

Electrical Engineering

An increase in agricultural demands and the need to sustainably protect crops has created a need for autonomous navigation through a vineyard with a verified pest detection and deterrence system. Developing this solution revealed several challenges. First, the robot must reliably navigate through structured, repetitive vineyard rows. Second, pests must be detected accurately under changing environmental conditions. Lastly, the system must respond with a chosen deterrent within an appropriate time window, all while minimizing false triggers. To address these challenges, this project uses a Husky A200 unmanned ground vehicle equipped with a 2D LiDAR sensor, an Intel RealSense RGB camera, …

Portable Food Pasteurization Using Pulsed Electric Fields (Pef), Thomas E. Mcmillan Iii

Electrical Engineering

Foodborne illnesses remain a significant public health concern, motivating continued development of alternative food pasteurization technologies. Pulsed electric field (PEF) treatment is a non-thermal pasteurization method that inactivates microorganisms through electroporation while minimizing thermal degradation of food products. The long-term objective of this project was development of a portable PEF food pasteurization system.

An iterative design approach was used to investigate generation of the high-voltage pulses required for PEF treatment. Multiple pulse forming network topologies were evaluated through simulation, leading to selection of a solid-state Marx generator architecture. A low-voltage five-stage prototype was designed, constructed, and tested to validate the …

Vlsi Spike Encoder For Spiking Neural Networks With 4-Bit Sar Adc, Jack Marshall, Wyatt Tack, Cameron Young, Ryken Thompson

Electrical Engineering

A spike encoder forms the interface between sampled data, such as image data or a sensor signal, and a spiking neural network by converting numerical input samples into discrete spike events. Unlike conventional artificial neural networks, spiking neural networks use spare, even-driven computation instead of continuous-valued activations. This makes them attractive for low-power embedded systems, biomedical electronics, and other edge applications where energy consumption, physical area, and thermal limits are important design constraints.

This project develops a modular spike encoder architecture for spiking neural networks with selectable support for temporal, rate, multi-spike, and delta encoding. Prior work has shown that …

Stakblocks, Micah Satoshi Inoshita, Ava Rose Doerschlag, Cody J. Ellis, Zach M. Lawton, Fernando M. Nalin, Nicholas Humphrey, Aiden Reed Anderson, Sara Maya Suratkal

Mechanical Engineering

Researchers developing sustainable building materials from agricultural waste need a faster way to prototype and evaluate small-scale samples under controlled temperature and pressure before scaling to production. Sponsored by Professor Pete Schwartz of Cal Poly San Luis Obispo, whose work focuses on sustainable technology for developing communities, this project aims to create a prototype testing device for researchers studying agricultural-waste bricks, with the University of Malawi as a potential future testing partner. The final product is intended to inform improved future designs rather than serve as a production-ready device, ultimately supporting the development of affordable, sustainable building materials for communities …