Digital Commons Network^™

Effect Of Degree Of Saturation On The Liquefaction Resistance Of Non-Plastic And Low-Plastic Soils, Kayla Rae Sorenson

Dissertations and Theses

Liquefaction and cyclic softening of fine-grained soils pose a significant hazard during earthquakes, yet the cyclic behavior of transitional soils such as silts remains poorly understood. Existing empirical liquefaction evaluation frameworks and ground improvement techniques are largely developed for sands and are not directly applicable to silts, particularly beneath existing infrastructure where conventional mitigation methods are often impractical or cost prohibitive. This knowledge gap is critical in regions such as the Pacific Northwest, where young, loosely deposited silts are prevalent and susceptible to seismic loading.

Microbially induced desaturation (MID) has emerged in recent years as a promising, minimally invasive ground …

Adolescent Math Anxiety: Teachers' Grouping Approach At The Intersection Of Multiple Student Identities, Dara Shifrer, Hannah Sean Ellefritz, David Hernandez-Saca, Allison Roda, Karla Santana Martinez

Sociology Faculty Publications and Presentations

Math anxiety represents a substantial barrier to many students’ math learning. In this paper, we apply interdisciplinary perspectives to data on over 13,200 ninth graders and their math teachers from the High School Longitudinal Study. Results suggest that being perceived as dis/abled relates to heightened math anxiety regardless of adolescents’ gender, or race and ethnicity. Our intersectional approach reveals that adolescents’ expressions of math anxiety do not always correspond with gender, racial, and ethnic stereotypes, with Black girls, Black boys, and Latine boys expressing relatively low levels of math anxiety. Finally, consistent with the principles of inclusion and universal design, …

Characterizing Indoor Surface Voc Contamination After The 2025 Los Angeles Fires, Brett W. Stinson, Emily Lei, Elliott T. Gall

Mechanical and Materials Engineering Faculty Publications and Presentations

We quantify volatile organic compound (VOC) emissions from indoor surface swabs and portable air cleaner (PAC) filters collected in a home 30 days after the 2025 Los Angeles wildland-urban interface (WUI) fires. We calculate emissions for 17 fire-relevant compounds. Surface emissions exceeded those of clean controls, and emissions from a windowsill in a room without a PAC were ∼15× and ∼2× higher for benzene and toluene, respectively, than rates reported in the literature for comparable materials unaffected by smoke/soot. Particle filters installed in PACs at the start of the fire emitted aromatics at rates comparable to those reported in a …

Post-Wildfire Water Quality And Aquatic Ecosystem Response In The U.S. Pacific Northwest: Science And Monitoring Gaps, Sara Wall, Jana E Compton, Ashley A. Coble, Beth M. Haley, Jiajia Lin, Allison Myers-Pigg, Justin Reale, Katie Wampler, Kevin D. Bladon, Kurt Carpenter, Heejun Chang, Multiple Additional Authors

Geography Faculty Publications and Presentations

An increase in the occurrence of large, high severity wildfires in the western Pacific Northwest (PNW), USA, has created an urgent need for science to better inform forest management and policy decisions to maintain source water quality in the region. The western PNW faces similar challenges to other regions with shifting wildfire regimes and large population centers reliant on surface water from forested catchments. However, the uniquely wet and highly seasonal climate of the western PNW suggests that findings from other, more frequently burned regions may not be directly applicable. To identify science, monitoring, and management gaps and opportunities in …

A Comprehensive Review Of Food Waste Management In Attaining Sdg 12.3 Goals: Insights From Asian Countries, Ping Hu, Lotifa Tamanna Toma, Ashraful Alam, Md. Tanvir Ahmmed, Md. Jahidul Islam, Kazi Farhana, Marjia Sultana, Miraj Ahmed Bhuiyan

Civil and Environmental Engineering Faculty Publications and Presentations

Food waste is one of the most important world-wide challenges whose environmental, economic and social impacts have far-reaching effects that include contributing to greenhouse gas emissions, resources depletion as well as the rising levels of food insecurity. These problems are further intensified in Asia due to high rate of urbanization, population growth, changing dietary habits, and lack of waste management facilities. These conditions complicate the fact that countries are increasingly struggling to achieve the United Nations Sustainable Development Goal (SDG) 12.3, which is to ensure that by 2030, half of the world has dropped per-capita food waste, and food losses …

Implementation Of Soil Improvement Techniques In The Dhaka Mass Rapid Transit Project A Comprehensive Case Study, Shoma Hore, Mosharof Al Alim, Maliha Farjana, Monir Hossain, Ripon Hore

Civil and Environmental Engineering Faculty Publications and Presentations

This paper evaluates Sand Compaction Pile (SCP) and Dynamic Compaction (DC) methods for enhancing soft soil in the Dhaka Mass Rapid Transit (MRT) project. Targeted interventions were required for the stratified soil profile, consisting of liquefiable sand (3–5 m thick) over soft clay (SPT ∼5): dynamic compaction for densifying the sand layer and soil-cement piles for stabilizing the underlying clay. Post-treatment Standard Penetration Test (SPT) values indicated that DC significantly improved the sand layer (SPT rose to 15–25) while SCP effectively strengthened the clay (SPT increased to 8–12). The Tongi-to-Uttara section (CP01) simultaneously addressed liquefaction concerns and settlement issues through …

Characterizing The Effect Of Plasticity Index On Monotonic And Cyclic Shear Behavior Of Natural Low-Plastic Silt Mixtures, Amir Barati-Nia

Dissertations and Theses

Low-plasticity silts are "transitional" soils prevalent in many seismically active regions, including the Pacific Northwest. Most research in the literature has historically focused on sand materials or clay materials, while low plastic silt does not fit either traditional "sand-like" or "clay-like" frameworks, resulting in a knowledge gap regarding this type of soil. Knowing the behavior of this type of soil is more important because it is susceptible to liquefaction or cyclic softening. Existing research on low-plastic silts is mostly based on either intact soil, where some parameters, such as the overconsolidation ratio (OCR) and plasticity index (PI), cannot be accurately …

Artificial Intelligence, Society 5.0 And Smart City Adaptation Initiatives For Businesses: An Integrated Approach, Ines A. M. Gila, Fernando A. F. Ferreira, Neuza C. M. Q. F. Ferreira, Florentin Smarandache, Momtaj Khanam, Tugrul Unsal Daim

Engineering and Technology Management Faculty Publications and Presentations

The mass migration of human populations to urban areas has resulted in unprecedented challenges for city services. To address and find solutions for these emerging issues, decision-makers must embrace the smart city and Society 5.0 paradigms, which comprehensively tackle various dimensions of the problem and ensure adaptability to evolving citizen needs. Central to the success of these paradigms is technology, particularly artificial intelligence (AI). AI’s transformative capabilities enable the expansion of services, automation of tasks, efficient operationalization and processing vast amounts of data to address urban challenges, aligning with several sustainable development goals (SDGs) such as sustainable cities and communities …

High-Throughput Computational Framework For High-Order Anharmonic Thermal Transport In Cubic And Tetragonal Crystals, Zhi Li, Huiju Lee, Chris Wolverton, Yi Xia

Mechanical and Materials Engineering Faculty Publications and Presentations

Accurate first-principles prediction of lattice thermal conductivity (κ L) remains challenging in identifying materials with extreme thermal behavior. While the harmonic approximation with three-phonon scattering (HA + 3ph) is now routine, reliable κ L prediction often requires higher-order anharmonic effects, including self-consistent phonon renormalization, three- and four-phonon scattering, and off-diagonal heat flux (SCPH + 3, 4ph + OD). We present a state-of-the-art high-throughput workflow that unifies these effects and apply it to 773 cubic and tetragonal crystals spanning diverse chemistries and structures. From 562 dynamically stable compounds, we assess the hierarchical impacts of higher-order anharmonicity. For around 60% of materials, …

Three-Dimensional Topographical Effects On The Generation Of Internal Lee Waves, Haosen H.A. Xu, Xiaowei Zhu, Kaiwen Zheng

Mechanical and Materials Engineering Faculty Publications and Presentations

Internal lee waves generated by the interaction between geostrophic flows and ocean-floor topography are recognized as an important pathway for transferring energy from large-scale circulation to small-scale mixing in the deep ocean; however, energy fluxes inferred from field observations often fall well below estimates based on classical linear theory. Here, we use direct numerical simulations to examine how three-dimensional (3D) topographic structure alters the generation and energy pathways of internal lee waves. We simulated idealized stratified flows impinging on twodimensional (2D) and 3D sinusoidal topography in a radiating regime. We used Reynolds decomposition based on spatial averaging to isolate wave-induced …

The Risc-V Fpga (Rvfpga) Teaching Package, Daniel Chaver, Sarah Harris, Luis Pinuel, Olof Kindgren, Zubair Kakakhel, Chris Owen, Roy Kravitz, Jose I. Gomez-Perez, Fernando Castro, Katzalin Olcoz, Multiple Additional Authors

Electrical and Computer Engineering Faculty Publications and Presentations

RISC-V is a free and open-standard ISA based on RISC principles, allowing anyone to design, manufacture, and sell RISC-V chips and software. Its flexibility and growing ecosystem have made it popular in research, education, and industry, increasing the need for educational materials. This paper provides an in-depth description of the RVfpga course, which offers a solid introduction to computer architecture using the RISC-V instruction set and FPGA technology. It focuses on providing hands-on experience with real-world RISC-V cores, the VeeR EH1 and EL2 cores, developed by Western Digital and hosted by ChipsAlliance. The course targets students and educators in computing-related …

Clustering Of Temporal And Visual Data: Recent Advancements, Priyanka Mudgal

Computer Science Faculty Publications and Presentations

Clustering plays a central role in uncovering latent structure within both temporal and visual data. It enables critical insights in various domains including healthcare, finance, surveillance, autonomous systems, and many more. With the growing volume and complexity of time-series and image-based datasets, there is an increasing demand for robust, flexible, and scalable clustering algorithms. Although these modalities differ—time-series being inherently sequential and vision data being spatial—they exhibit common challenges such as high dimensionality, noise, variability in alignment and scale, and the need for interpretable groupings. This survey presents a comprehensive review of recent advancements in clustering methods that are adaptable …

Evaluating The Fate And Variability Of Soil Organic Carbon And Nitrogen Species Under Conservation Practices In The Raccoon River Watershed, Zhonglong Zhang, May Wu

Civil and Environmental Engineering Faculty Publications and Presentations

This study evaluates the fate and variability of soil organic carbon (SOC) stocks and nitrogen species using the latest version of the Soil and Water Assessment Tool– Carbon (SWAT-C) and assesses how conservation practices influence their dynamics in the Raccoon River Watershed (RRW). Dominated by intensive agricultural pro- duction, the RRW is a significant contributor of sediment and nutrient loads to local rivers and the Mississippi River. This SWAT-C model simulates the export of SOC and nitrogen species and evaluates their responses under varying management scenarios. Model calibration was performed for streamflow, sediment, nitrate, total nitrogen, and organic carbon with …

Research Progress On Generating Perfect Vortex Beams Based On Metasurfaces, Xiujuan Liu, Manna Gu, Ying Tian, Mingfeng Zheng, Bo Fang, Zhi Hong, Chee Leong Tan, Xufeng Jing

Electrical and Computer Engineering Faculty Publications and Presentations

This article reviews the latest advances in the generation and control of perfect vector beams using metasurfaces. In recent years, metasurfaces have garnered increasing interest due to their simple fabrication and easy integration. Perfect vortex beams (PVBs), as a type of vector beams, exhibit complex polarization states that require the superposition of multiple phases for their generation. The use of metasurfaces provides a compact platform for the generation of perfect vortex beams and enables more complex vortex beam control tasks, which are quite challenging for traditional optics. This paper begins by introducing the principle of perfect vortex beam generation using …

Solving The Middle School Math Problem To Increase Achievement, Andre Goodlow

Educational Leadership Professional Doctorate Dissertations

This study used improvement science to address persistent and disproportionate low mathematics achievement among middle school students, particularly Black/African American and Hispanic students, in an urban school district in the Pacific Northwest. Local data indicated significant deficiencies in math proficiency, with the target district exhibiting achievement disparities exceeding state averages. The project investigated root causes of low math achievement, prioritizing the enhancement of foundational math skills and the implementation of evidence-based interventions. The improvement theory centered on deploying an evidence-based core math curriculum and intervention program for incoming middle school students, tested through cycles during a four-week summer school program. …

Political Elections In The New Wave Of Media: The Celebrification Of The Presidency, Camille B. Moore

Anthós

This article examines the impact of social media on journalism leading up to the 2024 United States presidential election and how expectations of candidates have changed. By exploring the degradation of discourse in news and how polarization and cognitive biases have intensified with the widespread adoption of social media, previous candidate conventions have begun to crumble. This has, and will continue to have, a large impact on voting and democracy in America, as scholars have noted since the beginning of the 2000’s, in examining a shift in news preferences as pop culture gains influence. This work further examines recent scholarship …

Chatbot Therapy - Help Or Hindrance, Kadi Rae Smith

Anthós

Introduction

Generative artificial intelligence (Gen-AI) chatbots are complex computer programs designed to mimic human conversations using programming that incorporates large language models (LLM) and natural language models (NLM) to simulate human interactions that are being rapidly integrated into everyday life across an increasing amount of online platforms. This article explores the applications and efficacy of chatbots for mental healthcare, from self-directed chatbot interactions to clinician-supervised implementation of chatbot-based therapeutic tools, weighing the benefits and limitations of this ever-expanding technology.

Methodology/Taxonomy

A literature review was conducted primarily using Web of Science, accessed through Portland State University, and Google Scholar, with specifications …

Into Me See: Visibility, Recognition, And The Need To Be Seen In Kazuo Ishiguro’S Never Let Me Go, Vicki L. Wine Carney

Anthós

While critical scholarship on Kazuo Ishiguro’s Never Let Me Go often emphasizes bioethics, transhumanism, and the commodification of life, this lens overlooks the novel’s profound engagement with the psychological necessity of visibility. This paper argues that the tragedy of the clones is fundamentally a crisis of recognition, where invisibility is not incidental but structurally produced to facilitate exploitation. Drawing on Caroline Levine’s concept of the "Form of Utility" and Axel Honneth’s Theory of Recognition, this study examines how systemic indoctrination and objectification deny the clones their innate humanity to soothe the conscience of the "normals." Furthermore, it analyzes the characters’ …

Numerics: A .Net Library For Numerical Computing, Statistical Analysis, And Risk Assessment, C. Haden Smith, Woodrow L. Fields, Julian Gonzalez, Sadie Niblett, Brennan Beam, Brian Skahill

Mathematics and Statistics Faculty Publications and Presentations

Numerics is a free and open-source numerical computing library for .NET, developed by the U.S. Army Corps of Engineers Risk Management Center (USACE-RMC). The library provides 43 univariate probability distributions with L-moment and maximum likelihood parameter estimation, eight Markov Chain Monte Carlo (MCMC) samplers for Bayesian inference, bootstrap uncertainty quantification, bivariate copulas, optimization algorithms, and numerical methods for integration, differentiation, root finding, and linear algebra. Numerics targets engineers, scientists, and analysts working in infrastructure risk assessment, flood frequency analysis, and Monte Carlo simulation within .NET-based enterprise systems. The library supports .NET 8.0 through 10.0 and .NET Framework 4.8.1 and is …

Scalar Source Localization Using Multi-Sensor Domains Of Dependence In Turbulent Channel Fow, Zejian You, Xiaowei Zhu, Qi Wang

Mechanical and Materials Engineering Faculty Publications and Presentations

Tracking hazardous events such as wildfire smoke, coastal oil spills, or chemical releases in natural environments is complicated by turbulent dispersion and molecular diffusion. This study presents a method to localize pollutant sources rapidly and accurately using infinite time-averaged measurements from a multi-sensor network, leveraging the duality between mean forward and adjoint scalar fields. The forward-adjoint duality states that measurements at the sensor (forward feld) are equal to the adjoint field at the source, providing crucial spatial information about the source. Consequently, the adjoint scalar fields can be interpreted as the domain of dependence for the sensor observations [1, 2]. …

Data And Code For: Combined Effects Of Forest Fire And Climate Warming On Seasonal Snow In The Western Oregon Cascades, Joseph D. Vigil

Environmental Science and Management Datasets

This dataset supports a study examining the combined effects of forest fire and climate warming on seasonal snow in the Breitenbush watershed of the western Oregon Cascades. The archive includes daily SnowModel snow water equivalent outputs for forested, current post-fire, mid-century, and end-century climate scenarios; field meteorological and manual snow observations; station metadata; modified SnowModel code used to represent post-fire snow-albedo decay; and R code used to calculate snow metrics and statistical comparisons reported in the associated manuscript. Derived results and documentation are included to support reproduction of the primary analyses.

Heat Misers, Snow Misers, And Cognitive Misers: The 'Nukewarm' Perceptions Of Nuclear Power, Tyler Williams

Dissertations and Theses

Rising energy demand in the United States necessitates alternatives to fossil fuels, yet renewable energy sources alone are insufficient to meet this demand. Nuclear power presents a promising option but faces persistent public hesitancy. This study examines how heuristic-based biases relate to American's risk-benefit perceptions towards nuclear power. Guided by the heuristic-systematic model. Results indicate that competence and affect are related to risk-benefit perceptions, and naturalness shows no relationship with risk perceptions but does correlate with benefit perceptions. Implications highlight the importance of affect-driven communication strategies for nuclear communicators, while also underscoring the need for participatory approaches that foster trust …

Aquatic Invasive Species Survey And Treatment On Lake Umatilla And Lake Celilo 2024-2025 Report, Jacob Rose, Gabriel E. Campbell

Center for Lakes and Reservoirs Publications and Presentations

Flowering Rush (Butomus umbellatus) is an invasive aquatic plant in the Pacific Northwest that threatens salmon habitat. The Center for Lakes and Reservoirs staff surveyed for this and other aquatic species from 2024 and 2025 in the Columbia River in Lake Umatilla and Lake Celilo. This document summarizes their survey efforts including their protocols, data, and small-scale removal efforts.

Estimating Sediment Properties Using A New Source Level Function For Wind-Driven Underwater Sound Derived From Long-Term Archival Data, S Bruce Martin, Martin Siderius

Electrical and Computer Engineering Faculty Publications and Presentations

Wind-driven breaking waves generate the background sound throughout the ocean. An accurate source level for wind-driven breaking waves is needed for estimating the ambient sound levels needed for sound exposure modeling, environmental assessments, and assessing the detection performance of sonars. Previous models applied a constant roll-off of sound levels at -16 dB/decade at all wind speeds, and these models' source levels were flat at frequencies below ∼1000 Hz due to a lack of measurements. Here, we analyzed 16 long-term archival datasets with limited anthropogenic sound sources to estimate the wind-driven source level down to 100 Hz. We estimated the site-specific …

Coolies Of Shimla: Modern Slavery As Relic Of The British Raj, Priya Kapoor

Politics and Global Affairs Faculty Publications and Presentations

Coolie labor needs to be understood as a contemporary transnational practice rooted in local practices of feudal kings and the British Empire. When the British Raj established Shimla as its summer capital in 1864, they did not eliminate archaic labor practices; instead, they cleverly modified them to serve the Empire’s infrastructural needs. Under the guise of reform, the British introduced nominal pay to bypass anti-slavery laws, effectively rebranding the forced laborer as the "coolie"—a racialized linguistic construct that signified a state of permanent subalternity. This labor force was the veritable backbone of the Raj, manually carving the treacherous Hindustan-Tibet Road …

Applications Of Artificial Intelligence In Dental Malocclusion: A Scoping Review Of Recent Advances (2020-2025), Man Hung, Owen Cohen, Nicholas Beasley, Cairo Ziebarth, Connor Schwartz, Alicia Parry, Martin S. Lipsky

Institute on Aging Publications

Introduction:

Dental malocclusion affects more than half of the global population, causing significant functional and esthetic consequences. The integration of artificial intelligence (AI) into orthodontic care for malocclusion has the potential to enhance diagnostic accuracy, treatment planning, and clinical efficiency. However, existing research remains fragmented, and recent advances have not been comprehensively synthesized. This scoping review aimed to map the current landscape of AI applications in dental malocclusion from 2020 to 2025. Methods: The review followed the Joanna Briggs Institute methodology and the PRISMA-ScR guidelines. The authors conducted a systematic search across four databases (PubMed, Scopus, Web of Science, and …

Mechanical Improvements And Control Implementation On A Biomimetic Quadruped Model, Matthew Jack Lutz

Dissertations and Theses

Robotic development started billions of years after earth first began biological prototyping. While the evolutionary process in animals is quite different from robotic prototyping, it still remains no surprise that animals remain more agile, more efficient, and more adaptable than even the most advanced engineered robots to date, simply due to the sheer length of their improvement process. While bridging this improvement gap between deficits in robots and the abilities of animals is difficult, a specific subfield of robotics engineering has attempted to do so using biomimetic robotics. At Portland State, the Agile and Adaptive Robotics Lab (AARL) studies these …

An Integrated Multivariate Econometric Modeling Framework For Risky Driving Behavior Related Crashes: Evaluating Crash Risk And Severity Across Zones, Pabitra Kumar Roy

Dissertations and Theses

Rapid advancements in crash modeling have yet to fully integrate multiple behavior-driven crash types and their severity outcomes within a single, scalable framework, specially in a way that captures the sequential nature of these behaviors where one risky action may amplify another. This study proposed an integrated multivariate econometric framework to jointly model crash frequency and severity outcomes for three major behaviorally driven crash types: alcohol-related, distraction-related, and aggressive-driving-related crashes. Specifically, using Oregon's 2022 census block group-level crash data, we propose an Integrated Multivariate Negative Binomial – Generalized Ordered Probit Fractional Split (IMNB–GOPFS) model to analyze these dimensions simultaneously while …

Leveraging High-Performance Cloud Computing To Model Underwater Acoustic Propagation And Scattering From Time-Evolving Rough Sea-Surfaces Using The Finite-Difference Time-Domain Method, James Alexander Higgins

Dissertations and Theses

This dissertation presents a two-dimensional (2D) Finite-difference Time-domain (FDTD) model for simulating underwater acoustic propagation and scattering from a one-dimensional (1D) time-evolving rough sea-surface. The techniques discussed are extendable to three spatial dimensions. Traditional acoustic modeling techniques often rely on a "frozen" sea-surface assumption, which proves inadequate for long-duration signals interacting with the time-evolving boundary at many different wave height displacements during its transit. To address this, a new FDTD update equation incorporating a variable subgrid is developed, significantly enhancing spatial accuracy at the boundary without increasing computational cost or compromising stability.

The model's accuracy is rigorously validated against established …

Lattice Thermal Transport Beyond The Quasiparticle Approximation: Nontrivial Spectral Competition Between Three- And Four-Phonon Interactions, Yi Xia

Mechanical and Materials Engineering Faculty Publications and Presentations

The breakdown of the quasiparticle approximation (QPA) for phonons in strongly anharmonic materials necessitates advanced first-principles frameworks for accurate lattice dynamics and thermal transport predictions. We develop a comprehensive beyond-quasiparticle approximation (BQPA) approach incorporating both three- (3ph) and four-phonon (4ph) interactions and apply it to investigate lattice thermal conductivity (κL) in MgO, PbTe, and AgCl – materials that span a broad spectrum of anharmonicity, from weak to severe anharmonic regimes with overdamped phonons. We reveal that while BQPA consistently increases κL relative to QPA due to phonon softening when considering only 3ph interactions, the inclusion of additional 4ph interactions hardens …