Engineering Commons^™

Addressing System Strength And Reliability Concerns In Renewable Energy-Based Weak Grids Using Synchronous Condensers Determined By Hybrid Gru-Classical Optimization Method, Md Ohirul Qays, Iftekhar Ahmad, Daryoush Habibi, Mohammad A.S. Masoum, Thair Mahmoud

Research outputs 2022 to 2026

Owing to the higher-integration of renewable energy generators (REGs), conventional coal-based synchronous generators are being decommissioned from generation fleets, resulting in system strength and reliability concerns. Along with the increasing load demand, deficiency of system strength can be a huge risk to system stability and can eventually lead to blackouts by disconnecting REGs from grid systems. In the literature, researchers and power engineers have proposed to deploy synchronous condensers (SynCons) as a mitigation strategy to address the system strength and reliability challenges. SynCons are, however, expensive and require investigation for higher reliability results before installation. To address the concerns, SynCons’ …

Autonomous Vehicle Adoption Behavior And Safety Concern: A Study Of Public Perception, Fatemeh Nazari, Mohamadhossein Noruzoliaee, Abolfazl (Kouros) Mohammadian

Civil Engineering Faculty Publications

Realizing the economic and societal benefits of autonomous vehicles (AVs) hinges on widespread public acceptance. However, existing research offers limited insights into two key behavioral factors shaping AV acceptance, namely, perceived AV safety concern and travel behavior, the latter reflecting how heterogenous mobility patterns influence the AV acceptance. These factors are often treated as exogenous, limiting insight into their true behavioral interdependencies with AV acceptance and their distinct behavioral roots. This study addresses these gaps by introducing a recursive trivariate econometric model that jointly estimates AV acceptance, perceived safety concern, and current travel behavior (proxied by annual vehicle-miles traveled or …

Evaluating The Impact Of Aggregate Size And Reinforcement On Alkali-Silica Reaction In Concrete Through Nondestructive Testing Techniques, Li Ai, David Bianco, Vafa Soltangharaei, Rafal Anay, Mahmoud Bayat, Paul Ziehl

Civil Engineering Faculty Publications

This research investigates different nondestructive evaluation (NDE) methods to assess concrete under alkali-silica reaction (ASR) development. Four methods including acoustic emission (AE), ultrasonic pulse velocity (UPV), crack width measurement, and strain measurement were applied to reactive and control specimens under accelerated ASR conditioning. The innovation lies in using NDE methods to monitor concrete with varying aggregate sizes, quantifying method sensitivity through measured indices, and highlighting the effectiveness of each method to capture ASR development. The results indicate that the unconfined reactive fine-aggregate sample exhibited isotropic expansion, while coarse-aggregate specimens showed around 50 % greater longitudinal expansion and AE cumulative signal …

Explainable Machine Learning And Life Cycle Assessment For Sustainable Design Of Fiber-Reinforced Asphalt Concrete, Xiao Tan, Jianglei Xing, Soroush Mahjoubi, Pengwei Guo, Ziyao Wei, Yuan Wang, Jie Ren, Li Ai, Weina Meng, Yi Bao

Civil Engineering Faculty Publications

Conventional asphalt concrete has a limited lifespan due to cracking, deformation, and environmental degradation, driving the development of fiber-reinforced asphalt concrete (FRAC). However, key gaps remain in current data-driven FRAC studies due to small and homogeneous datasets, “black-box” machine learning models, and trade-offs between mechanical-sustainable performance, failing to provide a transparent understanding of features governing FRAC behaviors. This paper proposes a framework integrating explainable artificial intelligence and life cycle assessment (LCA) to advance mechanical and sustainable design of FRAC. A dataset of 2490 laboratory samples covers 15 input features and 3 mechanical outputs. Eight machine learning models, along with a …

Tourniquet Tester, Tyler Offerman, Thuy Nguyen, Ryan Ly, Cody Hoeptner

Biomedical Engineering

The Tourniquet Tester is a device intended to be used as a standardized testing device for tourniquets. Due to the lack of a standard testing device for testing tourniquets that can produce accurate and reproducible results, it is difficult to test the efficacy of tourniquets currently being sold on the market. A standard testing device that can produce consistent and reproducible results would allow tourniquet manufacturing companies to properly test the efficacy of their product and develop proper guidelines and directions for users of the product. Medical professionals and military personnel who may use tourniquets in their line of work …

Babycheck, Ayla V. Campbell, Eleanor M. Tweedy

Biomedical Engineering

The BabyCheck project was created to design and test a device that can collect a small blood sample from the fetal scalp during labor. The goal is to reduce uncertainty when fetal heart rate tracings are unclear, especially in Category II cases where it can be difficult for clinicians to decide the safest next step. Current monitoring methods either rely on interpreting heart rate patterns or use more invasive procedures to gather biochemical information. BabyCheck was designed to provide a simpler and more controlled way to collect a small blood sample that could help guide these decisions.

The final prototype …

Jaundease Phototherapy Vest Test Plan, Sujay Panthulu, Jasdev Banwait, Gwynn Moss, Solomon M. Fernandez

Biomedical Engineering

Neonatal hyperbilirubinemia is a common condition affecting more than 60% of newborns, caused by an excess buildup of bilirubin in the blood due to the liver’s limited ability to process it efficiently [1]. The standard treatment involves hospital-based phototherapy, where infants are placed in incubators under blue light to break down bilirubin in the skin. Although effective, this approach requires infants to remain under the lights for 12–18 hours per day, often with eye protection, and separated from their parents—disrupting early bonding and potentially contributing to toxic stress that can impact neurological and emotional development [2]. While at-home phototherapy solutions …

Improving Cellular Retention And Distribution To Promote Arteriogenesis In A Mouse Model Of Chronic Arterial Occlusion, Nancy Huang

Biomedical Engineering

Peripheral Arterial Occlusive Disease (PAOD) affects millions of people in the United States, creating pain, discomfort, and limited mobility due to restricted blood flow from obstructed arteries. While current treatments include lifestyle changes and revascularization procedures, these options are often insufficient or inaccessible because of procedural pain and socioeconomic barriers. In some cases, this can lead to critical limb ischemia and amputation as a last resort. Increasing blood flow to the extremities by enhancing collateral vessel growth, a biological process called arteriogenesis, with cell-based therapies can redirect blood flow around obstructions and has potential to mitigate and treat the effects …

Iud Insertion Pain Management, Sandhya Sridhar, Olivia Armas, Lucy Campochiaro

Biomedical Engineering

This project focuses on developing an atraumatic cervical stabilization device that serves as a modern alternative to the traditional tenaculum used during IUD insertion procedures. Current devices rely on sharp metal prongs that pierce the cervix and often cause significant pain and bleeding. The goal of this project is to design a device that provides the same stability and control for clinicians while eliminating the need to puncture cervical tissue. The device is intended to be used by gynecologists, nurse practitioners, physician assistants, primary care physicians, or any medical professional performing an IUD insertion. The device is intended to be …

Cpap Belly Prevent, Alek Corpuz, Emma Hoffman, Danielle Tran

Biomedical Engineering

Neonates with low gestation periods often face complications such as respiratory distress syndrome, or RDS, which increases risk for complications such as necrotizing enterocolitis. Use of bCPAP helps facilitate regular breathing, but can also force air into the stomach and consequently cause abdominal distention. Clinicians currently use an already inserted feeding tube to vent the accumulated air, however this interrupts the feeding process.

The PreVent device was developed to allow for simultaneous feeding and venting. The dual function minimizes interruptions to NICU nurse workflow and improves capability to relieve abdominal distention before the onset of adverse complications.

Newborn Spinal Needle, Allison Inouye, Kyle Morton, Evan Russell

Biomedical Engineering

Spinal punctures, or lumbar punctures, are important diagnostic procedures used to collect cerebrospinal fluid (CSF) to diagnose issues in the central nervous system (CNS) such as meningitis. While these procedures are routinely performed on adult and neonatal patients, the current tools are not optimized for use on newborns. Existing spinal needles are often modified versions of adult devices, leading to challenges in fluid collection efficiency, user ergonomics, and patient safety when used in neonatal care.

The Newborn Spinal Needle Project aims to design and develop a spinal needle specifically optimized for neonatal anatomy and clinical workflow. The goal is to …

Orthopedic Bone Drill, Logan G. Schmid, Matthew T. Wold, May Geng

Biomedical Engineering

This project aims to design a bone drill for orthopedic procedures which alleviates the heat generated in the bone during drilling.

Joint Capacity Allocation And Job Assignment Under Uncertainty, Peng Wang, Yun Fong Lim, Gar Goei Loke

Research Collection Lee Kong Chian School Of Business

We study a multi-period joint capacity allocation and job assignment problem. The goal is to simultaneously allocate resources across J different supply nodes and assign jobs from I different demand origins to these J supply nodes, so as to maximize the reward for matching or minimize the cost of failure to match. We consider three features: (i) supply is replenishable after some random time, (ii) demand is random, and (iii) demand can wait and needs not be fully fulfilled immediately. Such problems emerge in many service management settings such as fleet re-positioning for car-sharing, and patient management in healthcare. We …

Development Of A Framework For Identifying Asphalt Pavement Cracking Distresses Using Machine Learning, Dingxin Cheng

Mineta Transportation Institute

Asphalt pavement cracking is one of the most critical distresses affecting pavement performance and service life. When pavement deteriorates, it can lead to safety hazards, higher vehicle maintenance costs, and expensive repairs for cities and states—making early detection essential for everyone who relies on the roadway system. To address this challenge, the research team developed a prototype cracking identification system that integrates a customized machine learning model with computer vision algorithms. High-resolution images collected from drones or ground-based cameras are processed within the system to automatically detect and classify major cracking types. The core of the framework utilizes the You …

A Knowledge Transfer-Based Membrane Evolutionary Algorithm For Solving Large-Scale Sorted Waste Collection Problem With Timeliness, Wenxue Zhang, Boquan Gao, Aldy Gunawan, Yunyun Niu, Jianhua Xiao

Research Collection School Of Computing and Information Systems

The sorted collection of municipal solid waste has emerged as an effective waste management strategy due to varying timeliness requirements across different waste types, giving rise to the critical research challenge of timeliness-based waste collection. While existing algorithms primarily focus on small-scale versions of this problem, solving large-scale timeliness-based waste collection problems remains particularly challenging. To tackle this issue, this paper proposes a knowledge transfer-based membrane evolutionary algorithm. Specifically, the original problem and simplified problem are constructed in different membranes respectively, and the knowledge transfer learning mechanism is incorporated into the membrane evolutionary algorithm, enabling effective information exchange between the …

Design And Development Of A 12-Degree-Of-Freedom Quadruped Robot, Kai De La Cruz

Master's Theses

This thesis presents the design, analysis, and experimental validation of a 12-degree-of-freedom (DOF) quadruped robot developed as a research platform for legged locomotion and control. The system builds upon the Cal Poly Legged Robotics Group’s prior 8-DOF quadruped, addressing key limitations in manipulability, load distribution, and mechanical robustness by introducing a 3-DOF leg architecture.

The mechanical design emphasizes lightweight construction, structural integrity, and modularity to support future research extensions. Static and dynamic loading models were developed to inform component sizing and material selection. A carbon-fiber chassis and redesigned leg assemblies were fabricated and validated through finite element analysis and physical …

Sea Level Trends Near Critical Levees In The Sacramento-San Joaquin Delta, Reyna Sanchez Gomez

Master's Theses

The Sacramento-San Joaquin Delta (Delta) levee system faces threats from rising sea levels, land subsidence, and deteriorating levees, all of which pose risks to California’s primary surface water supply. The purpose of this thesis is to assess relative sea level rise (RSLR) and estimate the spatially varying factors that influence water levels in the Delta. This thesis extends the work of Baranes et al. (2023) to the period 1975-2022 by appending recently acquired water-level records (1975-1982) to modern datasets (1982-2022) from 10 water-level stations. These water level datasets were digitized, quality-assured, and referenced to a common geodetic datum, as described …

Demystifying Hardware Formal Verification For Undergraduate Education: A Risc-V Processor Case Study With Coursework Implementation, Riley A. Peters

Master's Theses

Hardware verification engineers apply formal methods to prove that a digital device always behaves according to its specification. This differs from traditional functional verification, in which engineers establish correctness by repeatedly sending test inputs to the device and comparing the outputs against a reference model. With the growing complexity of integrated circuits, the demand for digital verification engineers with formal methods experience has continued to increase. However, California Polytechnic State University: San Luis Obispo's current curriculum lacks dedicated material to prepare students for these roles.

This thesis seeks to address the lack of formal methods material through two efforts. First, …

Ƒ(Cell): Software For Reproducible Analysis Of Optoretinograms, Robert F. Cooper, Mina Gaffney, Brea D. Brennan, Niko Rios

Biomedical Engineering Faculty Research and Publications

Purpose: There has been a marked increase in use of a noninvasive functional imaging technique called optoretinography (ORG). As more groups use ORGs, it is crucial to have a consistent methodology, and understand what analysis parameters influence repeatability. In this work, we present an open-source software library called ƒ(Cell) designed to facilitate reproducible and repeatable analyses of ORG data.

Methods: We designed ƒ(Cell) as a Python software library that can co-register and analyze ORG datasets, while also enabling process auditing. To validate the software, we used our previously obtained normative optoretinography datasets as well as datasets from six …

Fixel-Based Analysis Of Pretreatment Mri Identifies White Matter Abnormalities In Pediatric Anti-Nmdar Encephalitis, Daniel Ackom, Janine Taitt-Tap, Scott A. Beardsley, Ricardo Vega, Alyssa Jobe, Andrew J. D. Crow, Brian Schmit, Lileth Mondok, Pradeep Javarayee

Biomedical Engineering Faculty Research and Publications

Anti-N-methyl-D-aspartate receptor (anti-NMDAR) encephalitis is an autoimmune disorder in which conventional MRI often appears normal, leading to clinical–radiologic dissociation and hindering early diagnosis and monitoring. We retrospectively studied five pediatric patients with anti-NMDAR encephalitis and compared their pretreatment diffusion MRI to age- and sex-matched controls. Using fixel-based analysis (FBA), we quantified tract-specific white matter abnormalities at the individual level. All patients showed significantly reduced fiber density and cross-section, with patterns ranging from focal to widespread involvement. In two patients, FBA abnormalities corresponded to seizure lateralization on EEG despite normal MRI, emphasizing FBA's added value in detecting seizure-concordant injury. One patient, …

Improving Interlimb Coordination And Paretic Limb Use After Stroke Using A Novel Robotic Split-Crank Pedaling Device: A Cross-Sectional Study, Tom S. Ruopp, Brian Schmit, Sheila Schindler-Ivens

Biomedical Engineering Faculty Research and Publications

Background. Many stroke survivors cannot walk effectively, even after rehabilitation. Causes include impaired muscle activation, poor interlimb coordination, and limited restorative interventions. To address this, we developed CUped (pronounced “cupid”), a motorized split-crank pedaling device designed to compel use of the paretic limb and retrain interlimb coordination. We examined its within-session effects, comparing three proportional control schemes—assist (A), resist (R), and assist plus resist (A + R)—to identify which best promotes recovery-related movement.

Methods. Nineteen individuals with stroke and eleven controls pedaled in 5-min bouts, one per control scheme. Each bout included pre-test, exposure, and post-test periods. Participants were instructed …

Orthogonal Time Frequency Space Modulation For Underwater Acoustic Communication Systems: A Review, Bevek Subba, Quoc Viet Phung, Stefan Lachowicz, Walid K. Hasan, Muhammad Haziq, Daryoush Habibi, Iftekhar Ahmad

Research outputs 2022 to 2026

Underwater Acoustic Communication (UAC) has garnered significant attention due to its applications in marine science, defence, and exploration. With the vast majority of the Earth's surface covered by water, there is a growing demand for reliable and effective communication techniques in underwater environments. However, the underwater acoustic channel is the most challenging channel due to its harsh characteristics, which significantly hinder the reliability and performance of UAC systems. Orthogonal Time Frequency Space (OTFS) modulation has emerged as a promising solution for next-generation UAC systems to address high Doppler and high mobility scenarios. It has demonstrated tolerance to fast time-varying channel …

Magnetically Driven Engineering Of Magnetic Hydroxyapatite/Ca Ro Membranes: Enhancing Surface Physicochemical Properties For High-Performance Water Desalination, Fariba Oulad, Ali Akbar Zinatizadeh, Sirus Zinadini, Amir Razmjou, Sara Eavani

Research outputs 2022 to 2026

This research focuses on the development of innovative hydrophilic reverse osmosis (RO) hydroxyapatite/cellulose acetate (HAP/CA) and magnetic-hydroxyapatite (M-HAP)/CA membranes, utilizing a phase-inversion technique with varying nanoparticles (NPs) concentration. The positioning of magneto-responsive M-HAP NPs within the advanced M-HAP/CA membranes was adeptly controlled using magnetic guidance during immersion- precipitation process in a coagulation bath. This precise control enabled a densely organized arrangement of M-HAP NPs, shifting from the membrane's core to its upper separation layer. Consequently, the barrier properties, mechanical integrity, and surface characteristics of the advanced M-HAP/CA membranes saw significant enhancement due to the uniform distribution of hydrophilic porous NPs …

Numerical Investigation On Enhancing The Performance Of A Parabolic Trough Collector Using A Threaded Absorber Tube, Shayan Pourhemmati, Abdellah M. Shafieian, Hussein A. Mohammed, Barun Kumar Das, Majid Tolouei-Rad

Research outputs 2022 to 2026

The growing global demand for energy and heightened environmental concerns have elevated the importance of solar energy harvesting in recent years. Parabolic trough collectors (PTCs) are widely utilized for capturing direct solar radiation; however, conventional PTC efficiency is limited by low convection heat transfer rate in the absorber section, which is then delivered to heat transfer fluid (HTF). This study numerically investigates the use of a threaded tube as a fluid flow disruption technique to enhance heat transfer rate within the absorber, with Reynolds numbers ranging from 4000 to 10,000. Three key geometric parameters of the thread: pitch (300, 150 …

State Of Charge Estimation Of Ev Secondary Battery Pack Using Hybrid Hedge Feedforward Feedback-Based Gated Recurrent Unit To Extend Lifespan, Md Ohirul Qays, Iftekhar Ahmad, Daryoush Habibi, Mohammad A.S. Masoum, Paul Moses

Research outputs 2022 to 2026

Accurate estimation of state of charge (SoC) and maintaining balanced charge levels across secondary battery cells are crucial in battery management systems (BMSs) to extend battery life while improving the performance and thermal stability of Li-ion batteries (LIBs) in electric vehicles (EVs). However, there are still underexplored challenges associated with circulating currents in electrochemical cells during continuous operation which can overheat battery packs, reducing their life span or result in dangerous thermal runaways. This paper investigates SoC estimation using various real-world charging and discharging profiles, along with charge-balancing strategies to enhance the longevity of parallel-connected Li-ion battery cells. A newly …

Evaluation Of Sanafoam Vaporooter Ii Stress On Activated Sludge Performance For Carbonaceous Removal And Nitrification, Ensiyeh Taheri, Ali Fatehizadeh, John Nazimek, Mustafa Nabi, Wayne Bagg, Amir Razmjou, Paul Nolan, Ratish Permala, Mehdi Khiadani

Research outputs 2022 to 2026

Root intrusion control in sewer pipelines often relies on chemical herbicides, yet their unintended impacts on downstream biological treatment remain underexplored. This study investigated the effects of Sanafoam Vaporooter II (SVII) on carbon removal and nitrification in activated sludge reactors (ASRs) under long-term operation. Two parallel bench-scale ASRs were installed and operated at Subiaco municipal wastewater treatment plant in Perth, Western Australia: one was exposed to incremental SVII concentrations (1–3000 mg/L), while the other served as an unamended control. Stoichiometric analysis revealed stable organic matter removal across all SVII doses. In contrast, nitrification decreased progressively at concentrations exceeding 128 mg/L. …

Green And Charge-Tuned Β-Cyclodextrin Polymers For Efficient Removal Of Pfas And Anionic Dyes From Water, Samira Sadeghi, Ahmad Najafidoust, Mark Mullett, Shayan Karimi, Masoumeh Zargar

Research outputs 2022 to 2026

Water contamination by per- and polyfluoroalkyl substances (PFAS) poses a major environmental challenge due to their persistence. This study evaluates positively charged, green-synthesized β-cyclodextrin polymers (β-CDP⁺) for the removal of perfluorobutanoic acid (PFBA) and perfluorooctanoic acid (PFOA) as short- and long-chain PFAS, respectively, from water. Methyl orange (MO) and acid red 1 (AR1), as anionic dyes, were used as proxies to optimize PFAS adsorption conditions. β-CDP⁺ exhibited high removal efficiencies (>90%) for all pollutants within 15–50 mg/L, reaching equilibrium within 30 min. Maximum adsorption capacities (Qm) were achieved for MO (335 mg/g), AR1 (384 mg/g), PFOA …

Design, Testing, And Safety Performance Of Movable Guardrail Systems: A Prisma-Based Systematic Review, Navid Hashemi Taba, Ahdieh Sadat Khatavakhotan, Majid Tolouei-Rad

Research outputs 2022 to 2026

Movable guardrail systems are increasingly used in work zones, reversible lanes, and temporary traffic operations; however, evidence on their crashworthiness, material performance, and operational reliability remains dispersed across multiple design typologies and regulatory frameworks. This PRISMA-compliant systematic review synthesizes 78 studies involving full-scale crash tests, validated finite-element simulations, field performance evaluations, and compliance evaluations under MASH, EN 1317, NCHRP 350, and AS/NZS 3845.1. The findings indicate that modular rigid barriers reliably achieve TL-3/TL-4 performance when joint alignment and foundation conditions are properly controlled; semi-rigid steel systems provide a practical balance between containment capacity and redeployability, but remain sensitive to post …

Shear Stability Enhancement In Fracture Plugging Zones: Unveiling Failure Mechanisms And Adhesive Benefits Through Photoelastic Analysis, Haoran Jing, Yili Kang, Chengyuan Xu, Lei Liu, Xiaopeng Yan, Zhenjiang You

Research outputs 2022 to 2026

Addressing lost circulation during drilling operations typically involves the utilization of lost circulation materials (LCMs) to create a fracture plugging zone (FPZ), which effectively decouples the wellbore fluid column pressure (Pw) from the formation pressure (Pf). This FPZ, comprised of aggregated granular LCM particles, frequently succumbs to shear stress, with shear failure being the predominant mode of structural failure, leading to ongoing fluid losses. To illuminate the failure mechanisms of the FPZ under conditions of escalating drilling differential pressure (Pw - Pf), we utilized photoelastic experiments to capture and visualize the evolving mesoscopic mechanical structure of the FPZ. Photoelastic images …

Machine Learning-Based Upscaling Of Rock Permeability From Pore Scale To Core Scale: Effect Of Training Dataset Size And Sub-Core Volumes, Yaotian Guo, Fei Jiang, Takeshi Tsuji, Yoshitake Kato, Mai Shimokawara, Lionel Esteban, Mojtaba Seyyedi, Marina Pervukhina, Maxim Lebedev, Ryuta Kitamura

Research outputs 2022 to 2026

Permeability characterizes the capacity of porous formations to conduct fluids, thereby governing the performance of carbon capture, utilization, and storage (CCUS), hydrocarbon extraction, and subsurface energy storage. A reliable assessment of rock permeability is therefore essential for these applications. Direct estimation of permeability from low-resolution CT images of large rock samples offers a rapid approach to obtain permeability data. However, the limited resolution fails to capture detailed pore-scale structural features, resulting in low prediction accuracy. To address this limitation, we propose a convolutional neural network (CNN)-based upscaling method that integrates high-precision pore-scale permeability information into core-scale, low-resolution CT images. In …