Engineering Commons^™

Moisture-Induced Degradation And Mechanical Durability Of Mineral-Filled Polylactide (Pla) Composites, Barbara Szaraniec, Aleksandra Ptaszkowska, Alicja Rapacz-Kmita

Journal of Sustainable Construction Materials and Technologies

This study investigates the influence of mineral fillers on the hydrolytic stability and mechanical durability of polylactide (PLA) composites under accelerated aqueous ageing conditions. Composites containing halloysite nanotubes (HNT) and bentonite-based fillers (BM, BS, BSP) at 2 wt.% were prepared using a powder-coating and injection moulding approach. Accelerated hydrolytic degradation was conducted at 50 °C for up to six weeks. The degradation behaviour was evaluated through mass variation, water absorption, incubation medium analysis (pH and electrical conductivity), mechanical testing, surface observations, and contact angle measurements. The results revealed a clear filler-dependent response. Bentonite-filled composites exhibited increased water absorption and accelerated …

Ai In Precision Medicine: Redefining Blindness Treatment Via Retinal Stem Cell Differentiation, Calissa Leong, Tiffany Nguyen

Interdisciplinary Design Senior Theses

Age Macular Degeneration (AMD) is currently the leading cause of blindness, driven by the degradation of Retinal Pigment Epithelial (RPE) cells. Stem-cell based therapies, particularly those involving induced pluripotent stem cells (iPSCs), typically consists of differentiating stem cells into RPE cells in vitro and transplanting them into the subretinal space. Our goal is to improve the accuracy of differentiation into RPE cells to better promote retinal regeneration. Traditional methods to alleviate symptoms of AMD is through therapeutic medications to slow disease progression, though stem cell therapy has emerged as a promising alternative. However, despite its potential, stem cell therapy presents …

Investigation Of Electrochemical Transport, Gate Leakage, And Transconductance Behavior In Pedot:Pss Organic Electrochemical Transistors, Vinay Bhudhraja, Bilal Khan, Abijeet Mehta

Health & Biomedical Sciences Faculty Publications

Organic Electrochemical Transistors (OECTs) are promising candidates for low-voltage bioelectronic systems due to their high transconductance, mixed ionic–electronic transport, and compatibility with flexible substrates. In this work, we investigate the electrochemical transport, gate leakage, and transconductance behavior of screen-printed PEDOT:PSS OECTs, with emphasis on the relationship between ionic coupling and output characteristics. Key electrical and electrochemical parameters—including drain current modulation, transconductance evolution, gate current behavior, and capacitance–voltage response—were systematically analyzed to elucidate the mechanisms governing device operation. The results reveal clear trade-offs between parasitic resistance, volumetric electrochemical capacitance, and effective gate control, which in turn influence signal integrity and amplification …

Comparative Analysis Of Leaflet Materials, Stent Materials, And Stent Cell Density For Bileaflet Transcatheter Mitral Valve Design, Joseph Chibuike Nwokeafor, Joshua D. Hofmeister, Breandan B. Yeats, Lakshmi Prasad Dasi, Charanjit S. Rihal, Juan A. Crestanello, Leigh Griffiths, Mohamad A. Alkhouli, Hoda Hatoum

Michigan Tech Publications

Background: The biomechanical performance of bileaflet transcatheter mitral valves (TMVs) depends on complex interactions between leaflet material behavior and stent design. However, the contributions of leaflet materials and constitutive models, stent materials, and stent geometry to valve function and durability remain poorly understood. Methods: A parametric finite element study was conducted using a CAD model of a bileaflet TMV subjected to physiological pressure loading. Five leaflet material models were evaluated: 3 glutaraldehyde-fixed tissues—bovine pericardium (BP; FBP1, FBP2) and porcine pericardium (PP; FPP)—and 2 unfixed tissues—bovine (UBP) and porcine pericardium (UPP). BP was modeled as a linear elastic (FBP1) and Ogden …

Applications Of Geosynthetics In Tunnels Construction: A Sustainable Approach To Carbon Footprint Reduction, Ibraheem Rais, Abdullah H. Alsabhan, Md. Rehan Sadique, Shamshad Alam

Journal of Sustainable Construction Materials and Technologies

The use of geosynthetics has transformed tunnelling practices by enhancing structural integrity, durability, and environmental sustainability. This review adopts a systematic literature review design, covering publications from 2000 to 2025 sourced from Scopus, Web of Science, ScienceDirect, and Google Scholar. The selected studies were screened based on relevance, quality, and focus on tunnelling applications, then thematically analyzed into four domains: geosynthetic types, applications, sustainability, and performance evaluation. This review focuses on the applications of various geosynthetics, including geotextiles, geogrids, geocomposites, geocells, and geomembranes, in tunnelling projects. These materials play crucial roles in reinforcing tunnel walls and slopes, improving load distribution, …

Evaluating Chest-Worn Light Logger Adherence: Development And Application Of A Wear/Non-Wear Model, Carlyn Patterson Gentile, Adah Thomas, Ryan Shah, Blanca Marquez De Prado, Nichelle Raj, Christina Szperka, Geoffrey Aguirre

Student Papers, Posters & Projects

Light exposure plays an important role in overall health because it entrains circadian rhythms. Recent technological advances in wearable light loggers allow measurement daily light exposure habits. Using a chest-worn light logger, our goal was to (1) develop methodology for differentiating adherent versus non-adherent use, and (2) define differences in lighting intensity in indoor and outdoor environments, to improve data reliability in future clinical studies using this technology. Four testers used a 10-channel chest worn light logging device under different conditions of wear and non-wear (experiment 1), and another tester made measurements with the light logger across a variety of …

Operation Bite Block, Jennifer Aline Robles, Laura Marie Strobbe, William Pearce Graham, Annabelle Katherine Thalken

Mechanical Engineering

Current dental bite blocks, or mouth props, are typically manufactured in fixed sizes, and often result in patient discomfort, reduced procedural efficiency, and the need for dental offices to maintain multiple product sizes. This project sought to design, prototype, and validate an adjustable dental bite block capable of accommodating a wide range of patient mouth openings while maintaining comfort, structural integrity, sterilizability, and operator usability. Working in collaboration with Dr. Alan Latta, a practicing dentist in San Luis Obispo, the design process incorporated stakeholder feedback, patent and market research, engineering analysis, and iterative prototyping to develop a solution that addresses …

Bowl-O-Matic, Nathan Lin, Luis Torres, Jill Worthington, Aiden Foote

Mechanical Engineering

Adaptive physical education presents the unique challenge of accommodating individuals with diverse physical and cognitive abilities. Instructors and program designers must often integrate specialized equipment, fixtures, or features to ensure activities remain safe, inclusive, and user-friendly. Beyond accessibility, adaptive physical education highlights the importance of empowerment— enabling every participant to experience personal growth, confidence, and connection through movement. Friday Club, a local San Luis Obispo program supported by Cal Poly’s Kinesiology Department, embodies these values by providing adaptive physical activities that promote health and well-being for individuals with varying abilities. One of the most popular and regularly held activities is …

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 …

Emerging Biomaterials For Next-Generation Wound Healing: From Infection Control To Tissue Regeneration, Unqa Mustafa, Aiman Kaleem, Syeda Zunaira Bukhari, Hamna Riaz, Maryam Iftikhar, Muhammad Usman Munir, Xianghao Xiao, Mingwu Shen, Xiangyang Shi, Mostafa Yazdi, Ayesha Ihsan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Wound healing is a multifactorial biological process that regenerates damaged tissues through a series of molecular and cellular events in a coordinated manner. An interruption in this cascade can lead to impaired healing, especially in diabetic complications, where effective treatment is crucial for controlling infections and promoting tissue regeneration. Recent advances in bioengineering and digital health have catalyzed the development of next-generation wound therapies capable of actively modulating the wound microenvironment, promoting regeneration, and enabling real-time clinical assessment. This review summarizes the fundamentals of physiological wound healing and highlights the significant developments in biomaterial dressings and scaffolds, 3D bioprinting, as …

Pet Mobility Project, John Shelby, Lily-Rose Jolie Bacon, Andrea Yasmine Reyes

Biomedical Engineering

The Pet Mobility Project, sponsored by Terri Smith and Jasper Jackson, is an initiative aimed at providing a custom mobility aid to a pet in the San Luis Obispo community. Amber Rappozo’s young German Shepherd, LeDoux, was selected as the project’s recipient. LeDoux suffers from hindleg weakness and, as a result, has limited mobility. This document provides a comprehensive overview of the Pet Mobility Project, detailing the motivation, background, and design approach behind the development of a LeDoux’s custom mobility aid.

Cardiac Twitch Force Measurement System, Tara Hoffman, Sebastian Carrascal Gómez, Julian Macdonald

Biomedical Engineering

The goal of this project is to develop a low-cost and accurate force measurement system and method of measurement to be used in the testing of grown cardiac tissue samples. The primary stakeholder in this project is Dr. Luke Perreault, a biomedical engineering professor at California Polytechnic State University San Luis Obispo who is studying grown cardiac tissue rings, and any of his student lab personnel. Other stakeholders include other researchers in the tissue engineering field who require a similar form of testing to the methods developed in this project.

This document will introduce the identified problem and background as …

The Effects Of Carbon-Fiber Plates And Peba-Based Midsole Foam In Running Shoes On Lower-Limb Joint Kinetics And Kinematics In Recreational Female Runners, Jordan M. Allen

Master's Theses

The recent increase in long-distance running participation and the rapid advancement in footwear technology have created a need for research on injury prevention in this growing population of recreational runners. When “super shoes” were first introduced to the running scene, they caught the attention of runners worldwide with the rapid improvement in marathon performance [1]. Today, every major running brand offers its own version of a super shoe, each incorporating a carbon-fiber plate and PEBA-based midsole foam. While previous studies have shown the performance benefits of these shoes, a gap remains in the literature regarding how they impact knee, hip, …

Evaluation Of Laser Doppler Flowmetry And Transillumination Laser Speckle Contrast Imaging To Measure Blood Flow Change In Ischemia Mouse Hindlimb Models, Simon Park

Master's Theses

Peripheral Artery Disease (PAD), caused by plaque buildup and narrowing of the arteries, reduces blood flow to the extremities. Promoting collateral arteriogenesis can help redirect blood flow. However, simple growth of collaterals may not be enough to reverse PAD. Instead, the ability for the collaterals to vasodilate and control blood flow is important, meaning assessing collateral function is important for the arteriogenesis assesment. Although microscopy techniques can measure vasodilation, contrast limitations in larger vessels such as collaterals make blood flow measurements difficult. Techniques such as ultrasound or magnetic resonance imaging (MRI) can measure blood flow but have limitations with cost …

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 …

Effects Of Overcorrection On Mitigating Uncontrolled Tipping During Incisor Retraction Using Clear Aligners: Finite Element Analysis And In Vitro Experiment, Jianing Wang, Niko Burger, Bo Wang, Linxia Gu, Pengfei Dong

Biomedical Engineering Faculty Research and Publications

Uncontrolled tipping during incisor retraction with clear aligners continues to limit orthodontic treatment. Different countermeasures have been proposed to improve the predictability of aligners, such as power ridges and attachments, while their efficacy requires further investigation. This work investigated the biomechanics of the overcorrection in reducing the tipping angle and moment during incisor retraction with a clear aligner, through in vitro experiments and finite element analysis (FEA). Specifically, the influence of overcorrection angle (1 deg), retraction distance (0.15 mm), and the combination of both were assessed through in vitro experiments and the finite element simulation. Further computational simulations were conducted …

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.

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 …

Cathy’S Catcher, Marlee Scott, Regen Worsley, Alessandra Valenzano, Aviv Ben Zeev

Mechanical Engineering

Deep-sea fishing presents significant challenges for individuals with upper-limb differences, particularly when using prosthetic devices that are not designed for recreational fishing activities. This project developed a custom prosthetic fishing rod attachment for a user who had lost her forearm and desired a safe, comfortable, and independent method of fishing. Through interviews with the sponsor and an iterative design process, a lightweight aluminum attachment was created to interface directly with the user's existing prosthetic quick-connect system.

The design process included concept generation, CAD modeling, rapid prototyping with 3D-printed models, manufacturing, and user-centered refinement. The final design consists of a welded …

Restoreband: An Electromyography Band For Tracking Forearm Muscle Action And Activation In Post-Stroke Adults, Mairin T. Mullen, Melody Nwagwu, Kosuke Nishimura, Benjamin Miramon

Biomedical Engineering

This study involves the design of a non-invasive surface electromyography (EMG) band to estimate hand posture for individuals recovering from stroke and other neuromuscular disorders. The device is meant to measure forearm muscle activation to provide objective recovery data that can supplement traditional rehabilitation. Current EMG systems are often expensive, cumbersome, and difficult to use. The goal of this study is to develop an affordable, accurate, and easy to use solution that improves access to EMG motor monitoring.

The key stakeholders include stroke survivors, clinicians, and the project sponsor, Dr. Espinoza-Wade. This report includes project introduction, background, objectives, and project …

The Effects Of Adipose Tissue Trauma On Vascular Function After Collateral Arteriogenesis, Nathan Tran

Biomedical Engineering

Peripheral artery disease (PAD) affects an estimated 200 million people worldwide and is characterized by arterial narrowing that reduces perfusion to the limbs. Collateral arterioles can naturally restore blood flow through a remodeling process called arteriogenesis, making it a promising therapeutic target. However, the femoral artery ligation (FAL) model used to study arteriogenesis requires surgical access deep to the inguinal fat pad, and approaches for handling the fat pad vary widely across surgeons and protocols. Since adipose tissue harbors a large population of macrophages, the immune cells that govern arteriogenesis, fat pad manipulation may introduce confounding inflammatory stimuli that disrupt …

Development Of A Video-Based Tool To Measure Motor Asymmetry In Infants At Risk For Hemiparesis, Roha Ali

Master's Theses

Congenital hemiparesis is a unilateral motor impairment stemming from brain injury in utero or early postnatally. Hemiparesis can be difficult to detect in early infancy with current clinical tools. Yet, early identification of motor asymmetry could play a key role in the design of effective early intervention and rehabilitation strategies. This thesis presents the development and validation of a video-based tool designed to extract infant limb movement data using DeepLabCut’s (DLC) machine learning network. The pipeline was developed using videos of typically developing (TD) infants and infants with Asymmetric Perinatal Brain Injury (APBI), all at or under 3 months corrected …

A Security Framework For Pacemaker Lead Failure: Anomaly Detection System And Failsafe Policy Considerations, Ethan Wagner

Master's Theses

Embedded system security in implantable medical devices (IMDs) remains an underexplored challenge due to the unique constraints of these systems. Specifically, pacemakers are optimized for ultra-low power consumption to maximize device lifespan, are highly resource constrained, and demand reliable and correct operation to prevent severe health consequences. These systems rely on sensing electrodes, called leads, to detect cardiac activity and stimulate the patient’s heart when appropriate. Therefore, pacemaker lead integrity is a critical issue, as malfunction or compromise can result in device failure jeopardizing patient safety.

The security framework presented in this thesis integrates several works to proactively detect and …

Characteristic Stress And Strain Optimization Of Cardiovascular Catheters With Laser-Cut Hypotubes Using Finite Element Analysis, Kyle E. Hirth

Master's Theses

Cardiovascular catheter systems rely on laser-cut hypotubes to balance flexibility and structural integrity required for minimally invasive surgical procedures.  Optimizing these mechanical characteristics remains a significant challenge.  This study aims to investigate the influence of key laser-cut geometric parameters on the mechanical performance of hypotubes through finite element analysis.

Commercially representative laser-cut hypotubes were modeled and a finite element model was developed.   Geometric design parameters were varied across a design space consisting of pitch values ranging from 0.006 in. to 0.018 in. and cuts per revolution (CPR) ranging from 2.5 – 4.5.  For each pitch and CPR combination, loading stiffness …

Vergence Task-Based Neural Pathways With Binocularly Normal Vision And Comorbid Persistent Post-Concussive Symptoms -Convergence Insufficiency, Ayushi Sangoi

Dissertations

Binocular dysfunctions are more prevalent in the persistent post-concussive symptoms (PPCS) population than in the general population. The most prevalent binocular disorder is convergence insufficiency (CI), affecting 3-17% of the general population and up to 10 times as many people with PPCS. CI makes it difficult to fuse or maintain fusion on targets at near, and its symptoms include double or blurry vision and headaches when performing close-range tasks such as reading, which can exacerbate PPCS symptoms. Given controversy over the subjectivity and effectiveness of diagnostic tools and symptom surveys for both PPCS and CI, understanding why CI has high …

Membrane-Engineered Nanotherapeutic Platforms For Drug Delivery: Hollow Fiber Membrane Synthesis Of Lipid Nanoparticles, Biomimetic Nanocarriers, And Nanobubbles, Zhixiang Liu

Dissertations

Lipid-based nanocarriers have emerged as a cornerstone technology for RNA therapeutics, enabling effective intracellular delivery for applications ranging from vaccination to gene regulation. However, current manufacturing approaches, particularly microfluidic-based platforms, face inherent limitations in scalability, throughput, and structural tunability due to their reliance on confined channel geometries and restricted mixing architectures. Addressing these challenges requires fundamentally new strategies that decouple nanoparticle formation from traditional microscale flow constraints while maintaining precise control over physicochemical properties.

This dissertation presents a comprehensive framework for the design, engineering, and application of advanced lipid-based nanocarriers, centered on a hollow fiber membrane (HFM)—assisted nanopore-mediated assembly platform. …

Transcranial Ac Modulation Of Cerebellar Nuclear Activity In Awake Animals, Nuran Kavakli

Dissertations

Entrainment of cerebellar nuclear (CN) cells via cerebellar transcranial alternating current stimulation (ctACS) has been reported in animals under ketamine/xylazine anesthesia. Our main objective was to demonstrate modulation of CN activity in unanesthetized, freely moving animals using ctACS. Multi-channel carbon-fiber electrodes were implanted into the interpositus nucleus for recording multi-unit (MU) activity, and thin-film electrodes were implanted subcutaneously over the posterior cerebellum for stimulation. A frequency-domain-based metric was developed to quantify modulation from MU signals. The results demonstrated modulation in a wide range of frequencies (4 Hz-300 Hz) as in anesthetized animals. In contrast, the amplitude of the peak in …

Evaluation Of Medical Instrument Reliability For The Heath And Maddox Components Of The Accommodative-Vergence System, Jacob Chabuel

Theses

Binocular vision relies on the coordination of near response triad composed in part by the vergence and accommodative systems. Binocular dysfunctions linked to these systems impact the quality of life of those affected by complicating day-to-day tasks and leading to further health concerns. Clinical evaluations that diagnose dysfunctions and tailor therapies rely on subjective methods, creating a need for a reliable, quantitative, measurement tool. This is achieved using a haploscope, a tool that quantitatively measures and observes binocular vision to identify deficiencies within the eye. Modernization of a haploscope system, measurement of the Heath and Maddox components of the visual …

Robustness Of Ai-Driven Histopathology Under Real-World Adversarial Examples, Ruchik N. Yajnik

Theses

This robustness of histopathology classification models under adversarial and real-world perturbations resembling clinical artifacts is being investigated.

Using whole-slide images from the CAMELYON17 cohort, four representative architectures—ResNet-18, ResNet-50, HIPT-2MLP, and ViT-B/16 —are benchmarked across controlled pixel-level distortions and artifact-like transformations. Adversarial methods include iterative Fast Gradient Sign, Projected Gradient Descent, Salt-and-Pepper noise, and the Adversarial Watermark—Stain Shift (AWSS). Three defense strategies—Randomized Smoothing, Adversarial Training, and an Artifact Detector—are evaluated for their ability to preserve diagnostic accuracy and model reliability. Structured perturbations consistently degrade performance, with transformer-based models showing the greatest sensitivity. The benchmark developed here offers a reproducible framework for …