Digital Commons Network^™

Developing And Testing Low-Cost Air Cleaners For Safer Spaces During Wildfires, Brett W. Stinson, Elliott T. Gall

Mechanical and Materials Engineering Faculty Publications and Presentations

Air cleaning reduces indoor exposure to fine particulate matter (PM2.5) during wildfire smoke events. However, resource and cost constraints may limit access to air cleaning during such an event, as both commercial devices and the higher-rated MERV filters that do-it-yourself (DIY) assemblies typically rely upon tend to be expensive and in short supply. With these constraints in mind, we developed and evaluated several configurations of a novel, DIY air cleaner that uses common household fabrics as filtration media. Clean air delivery rates (CADRs) of the devices were experimentally evaluated in two ways: first, with independent measurements of flowrates and single …

Predation Of Appendicularians On Prochlorococcus, Carey Sweeney

Dissertations and Theses

Prochlorococcus is the most abundant photosynthetic cell on Earth. This picocyanobacterium is critical to primary productivity and biogeochemical cycles of the open ocean. While abiotic environmental factors that influence Prochlorococcus are relatively well-understood, biotic controls are less well known. Appendicularians are ubiquitous gelatinous zooplankton that feed on marine microorganisms including Prochlorococcus. However, the details of this feeding interaction are extremely understudied relative to its potential importance. In this study, I characterized the relationship between appendicularians and Prochlorococcus with laboratory experiments. I showed that feeding on Prochlorococcus changes with the life stage of the appendicularians and concentration of prey. I …

Framework And Methodology For Risk-Based Bridge And Tunnel Asset Management: Objective Risk Assessment And Network Level Evaluation, David Y. Yang, Arash Khosravifar, Diane Moug, Avinash Unnikrishnan

Civil and Environmental Engineering Faculty Publications and Presentations

This report presents the results of the project on establishing a general framework and methodology for risk-based bridge and tunnel asset management. The research was carried out at Portland State University in collaboration with engineers and officials at Oregon Department of Transportation (ODOT) and Federal Highway Administration (FHWA). The primary goal of the research is to achieve risk-based transportation asset management based on (a) objective and consistent risk assessment and (b) effective prioritization and optimization of intervention strategies. Volume I of this report presents methods and findings in the base phase (Phase I) of the project, which is focused on …

When Overextended Surface Allocation Turns To Groundwater: A Q Methodology Of Well Users In Oregon’S High Desert, Melissa Haeffner, Janet Cowal, Brandy Walker, Clare Mcclellan

Environmental Science and Management Faculty Publications and Presentations

As legal battles over surface water allocation in Klamath County, Oregon, USA have gained national attention, earning the name “Water Wars,” authorities have been increasingly turning to groundwater to compensate for water shortfalls. This case study aims to identify the nuanced perspectives of household groundwater well users who are affected by groundwater extraction. Using Q methodology, we uncover groundwater well users’ perceptions and to what extent they think water problems are dealt with fairly. We identify four water perspectives that differ in the degree to which respondents prioritize clean water accessibility, industry accountability, individual responsibility for water management, and trust …

Lithium And Water: Hydrosocial Impacts Across The Life Cycle Of Energy Storage, James J. A. Blair, Noel Vineyard, Dustin Mulvaney, Alida Cantor, Ali Sharbat, Kate Berry, Elizabeth Bartholomew, Ariana Firebaugh Ornelas

Geography Faculty Publications and Presentations

As a key ingredient of batteries for electric vehicles (EVs), lithium plays a significant role in climate change mitigation, but lithium has considerable impacts on water and society across its life cycle. Upstream extraction methods—including open-pit mining, brine evaporation, and novel direct lithium extraction (DLE)—and downstream processes present different impacts on both the quantity and quality of water resources, leading to water depletion and contamination. Regarding upstream extraction, it is critical for a comprehensive assessment of lithium's life cycle to include cumulative impacts related not only to freshwater, but also mineralized or saline groundwater, also known as brine. Legal frameworks …

Fem-Based Conductive Heat Transfer Analytical Description Of Solidification Rate And Temperature Gradient During Lateral Laser Beam Oscillation Welding Of Aluminum Alloy, Jason Cheon, Cheolhee Kim, Sanghoon Kang, Minjung Kang

Mechanical and Materials Engineering Faculty Publications and Presentations

This study investigates the feasibility of utilizing the finite element method (FEM)-based conductive heat transfer (CHT) analysis simulation to determine temperature gradients and solidification rates at the solid–liquid interface during laser beam oscillation welding. By comparing experimental observations with FEM-based CHT analysis, the underlying microstructural evolution and grain formation during welding were examined. FEM-based CHT enables the calculation of temperature gradients (G) and solidification rates (R), offering insights into the formation of equiaxed structures, which are crucial for suppressing hot cracking. Columnar-to-equiaxed structure transition thresholds, such as G/R and G³/R, accurately predict …

Large Length Scale Droplet Capillary Phenomena: Generation, Jump, And Capture, Karl Jeffrey Theodore Cardin

Dissertations and Theses

Understanding the life cycle of droplets, from generation to capture, for example, is critical to understanding environments from the air-sea interface to the indoor environment of the International Space Station. Investigations have been performed in this work to provide insight into three droplet phenomena, each ubiquitous in both terrestrial and microgravity settings, through a lens of capillary flow. Each investigation attempts to disentangle the effects of gravity from the effects of surface tension. A drop tower test campaign is performed for each of the three investigations. Models are developed and simulations are performed to rationalize the observations. Each investigation is …

"We're Going To Tear Up The Caldera So We Can Have An Electric Car": Competing Perceptions And Spatial Dimensions Of Open-Pit Lithium Mining In The Mcdermitt Caldera, Oregon, Elizabeth Bartholomew

Dissertations and Theses

As the world attempts to pivot away from fossil fuels and other greenhouse gas-emitting activities that fuel climate change, the proposed technological solutions all require raw materials, resources, and land; each of which have their own logistical and political dimensions. Lithium, a federally recognized critical mineral that is considered a crucial element in modern battery production, plays a vital role in decarbonizing efforts. Under the banners of national security, resource independence, and carbon mitigation goals, the United States has incentivized domestic lithium extraction, expediting exploration throughout the American West. The McDermitt Caldera, spanning from southeastern Oregon into northern Nevada, is …

Synoptic Drivers Of Extreme Precipitation In The Upper Yuba Watershed Of California, Emma Nichole Russell

Dissertations and Theses

The United States state of California is vulnerable to both droughts and extreme precipitation events due to the timing and processes of precipitation in the region. California's annual precipitation is dependent on a few strong storms and in addition to its Mediterranean climate, leads to great variability in precipitation both within and across years. While efforts to reduce the impacts of extreme precipitation events have been implemented, forecasting for these events remains a challenge in regions with complex terrain and dynamic meteorological drivers. In order to improve forecasting and preparedness for such events, it is important to understand the range …

Exploring The Social Processes Influencing The Well-Being And Social Integration Of Systemically Marginalized Students In Higher Education: A Mixed-Methods Approach, Zeinab Abbas Hachem

Dissertations and Theses

Comprising two manuscripts, this dissertation employs a mixed-methods approach to comprehensively examine the intrapersonal and interpersonal processes influencing the socioemotional well-being and social integration of systemically marginalized students. The first manuscript quantitatively explored the relationship between ethnic identity commitment and indices of well-being, the mediating role of social relationships, and the moderating roles of gender and immigrant generation status among Latinx college students (N = 707). Results suggested that ethnic identity commitment was positively associated with socioemotional well-being. Although both types of relationships were significant mediators on their own, maternal (vs. peer) relationship quality was the stronger mediational influence. Furthermore, …

Concolic Testing For Scripting Languages, Zhe Li

Dissertations and Theses

Scripting languages, such as JavaScript and Lua, are becoming more and more popular. They are typically easy to learn and use, making them accessible to a wide range of developers, even those with limited programming experience. Lua, for instance, is a lightweight, efficient, and versatile scripting language. It is designed to be easy to integrate into other systems and is often used as an embedded scripting language in larger applications such as NMap, which is a network scanning tool.

As another example, web front-end development with JavaScript (JS) is a popular choice for developers due to its ability to add …

Wind Plant Wake Losses: Disconnect Between Turbine Actuation And Control Of Plant Wakes With Engineering Wake Models, Ryan Scott, Nicholas Hamilton, Raul Bayoan Cal, Patrick Moriarty

Mechanical and Materials Engineering Faculty Publications and Presentations

Wake losses from neighboring plants may become a major factor in wind plant design and control as additional plants are constructed in areas with high wind resource availability. Because plant wakes span a large range of physical scales, from turbine rotor diameter to tens of kilometers, it is unclear whether conventional wake models or turbine control strategies are effective at the plant scale. Wake steering and axial induction control are evaluated in the current work as means of reducing the impact of neighboring wind plants on power and levelized cost of electricity. FLOw Redirection and Induction in Steady State (FLORIS) …

Modelling Postfire Recovery Of Snow Albedo And Forest Structure To Understand Drivers Of Decades Of Reduced Snow Water Storage And Advanced Snowmelt Timing, A. Surunis, K. E. Gleason

Environmental Science and Management Faculty Publications and Presentations

Forest fires darken snow albedo and degrade forest structure, ultimately reducing peak snow–water storage, and advancing snowmelt timing for up to 15 years following fire. To date, no volumetric estimates of watershed-scale postfire effects on snow–water storage and snowmelt timing have been quantified over decades of postfire recovery. Using postfire parameterizations in a spatially-distributed snow mass and energy balance model, SnowModel, we estimated postfire recovery of forest fire effects on snow–water equivalent (SWE) and snowmelt timing over decades following fire. Using this model, we quantified volumetric recovery of forest fire effects on snow hydrology across a chronosequence of eight sub-alpine …

Tribal Lands Population Projections: Celilo Village & Grande Ronde, Neal Marquez, Ethan Sharygin, Huda Alkitkat, Suniva Thangaraj, Gilbert Montcho, David Swanson, Joshua Wilde

Oregon Population Forecast Program

To achieve more affordable, fair, and equitable outcomes in the housing planning process, the Oregon Department of Land Conservation and Development and Oregon Housing and Community Services developed a plan to address past and ongoing obstacles to access to affordable housing. This plan incorporated population projections with detail by age, race/ethnicity, and disability status, and for American Indian tribal lands with which to make a more detailed assessment of housing access and future housing needs. This report, prepared by the Portland State University Population Research Center, includes updates to previously published forecasts for the Grand Ronde Community and Celilo Village.

The Conflict Between The United States And Iran And Its Effect On Iraq, Sarah Alsalih

Dissertations and Theses

This thesis examines the dynamic interplay between the United States and Iran and its repercussions on Iraq in the post-9/11 era. Against a backdrop of historical adversities, the research delves into the evolving relationship between the U.S. and Iran, elucidating its multifaceted dimensions and the consequential effects on Iraq. The central inquiry driving this investigation is: "Against the adversarial historical backdrop of U.S.-Iran relations, how has the relation between the two countries changed and impacted Iraq throughout the post 9/11 era?"

Drawing upon a comprehensive analysis through the lens of diplomatic interactions, military interventions, and regional dynamics, this study seeks …

Monitoring Water Meniscus Formation At Nanocontacts With Shear-Force Acousto Near-Field Microscopy, Xiaohua Wang, Rodolfo Fernandez, Theodore Brockman, Kacharat Supichayanggoon, Andres H. La Rosa

Physics Faculty Publications and Presentations

Shear-force acoustic near-field microscopy (SANM) is employed to monitor stochastic formation and post dynamic response of a water meniscus that bridges a tapered gold probe (undergoing lateral oscillations of a few nanometers amplitude at constant frequency) and a flat (gold or silicon oxide) substrate. As the probe further approaches the substrate, its amplitude decreases. Shear forces (of yet unknown precise origin) are typically invoked to explain the apparently pure damping effects affecting the probe's motion. Herein, SANM measurements underscore instead the role of near-field acoustic emission from the water meniscus as an elastic energy dissipation channel involved in shear interactions. …

“I Was Determined To Fulfill This Image Of Myself That I Wanted Of A ‘Good Asian Student’”: A Photovoice Study Of Asian American College Student Mental Health, Lalaine Sevillano, Joanna C. La Torre, Taylor A. Geyton

School of Social Work Faculty Publications and Presentations

Asian American (AsA) youth and emerging adults are growing at a faster rate than all other racial and ethnic populations in the United States. Burgeoning empirical evidence shows that they are experiencing increased adverse mental health outcomes since the start of the COVID-19 pandemic. Additionally, trends in AsA youth and emerging adults’ utilization and help-seeking behaviors remain low. Health equity scholars posit that the model minority stereotype continues to obscure and minimize these mental health disparities. The current study aims to contribute to this vital research through a Photovoice study with AsA emerging adults. Fourteen AsA undergraduate students (M age …

The Reddit Cannabis Subjective Highness Rating Scale: Applying Computational Social Science To Explore Psychological And Environmental Correlates Of Naturalistic Cannabis Use, Meredith C. Meacham, Alicia L. Nobles, Carlton ‘Cb’ Bone, Michael Gilbert, Johannes Thrul

Anthropology Faculty Publications and Presentations

Social media data provide unprecedented access to discussions of active, naturalistic, and often real-time cannabis use in an era of cannabis policy liberalization. The aim of this study was to explore psychological and environmental correlates of cannabis effects by applying computational social science approaches to a large dataset of unprompted reports of naturalistic cannabis use with corresponding self-reported numerical ratings of subjective highness. Post title text was extracted via the Pushshift dataset from N = 328,865 posts to the r/trees Reddit community, where posters self-assess and disclose how high they feel on a scale from 1 to 10 (M = …

Culture Or Power: The Eruption Of The Anglophone Crisis In Cameroon, Danielle Tagakou Talla

Dissertations and Theses

Located in Central West Africa, Cameroon has been the stage of a protracted conflict since 2016. The conflict called the "Anglophone crisis" is rooted in Cameroon colonial history. This is reflected in the composition of its population with a large majority of Francophones and only 20 percent of Anglophones. The subsequent thesis aims to examine the crisis between 2016 and 2022 and understand the shift in focus that happened in the early years of the conflict. Using a qualitative methodology, journal articles, books and recorded interviews will provide substantial sources to decipher the change from cultural focus to one of …

Assessing The Climate Resilience Of Quercus Garryana In The Portland Metro Region, Jess Rose Nettle Shamek

Dissertations and Theses

In the context of rapid global climate change, understanding the resilience of local tree species is essential for fostering effective environmental stewardship and community hopefulness. Oregon white oak (Quercus garryana), an emblematic species in the Pacific Northwest, has faced significant habitat loss and degradation since settler colonization. However, it also exhibits a predicted resilience to climate change, potentially leading to a range shift and expansion. Species resilience refers to the capacity of a species to persist and adapt in the face of rapid global climate change. Beyond vulnerability assessments and niche models, we know little about this species' …

Impacts Of Stream Habitat Restoration On Macroinvertebrate Assemblages: A Systematic Literature Review, Morgan E. Seitzer

University Honors Theses

Globally, river restoration has become a popular tool for improving the health of a watershed and restoring ecosystem services, but still has significant knowledge gaps. In certain areas and scientific communities, special attention has been given to the response of macroinvertebrates as a measure of restoration success. This systematic literature review aims to highlight and discuss the patterns in studies that have comparable before-and-after restoration data on macroinvertebrates after reconnecting stream channels to their floodplains. Macroinvertebrate sampling is a simple if not time-consuming task that can reveal important data about habitat quality. Because they serve as an important food source …

Isolation Of Gametophytic Selection And Selective Embryo Abortion In Mimulus Guttatus, Desmond C. Willson

University Honors Theses

A lack of genomic studies examining gametophytic selection (GS) and selective embryo abortion (SEA)--which occur during the reproduction of angiosperms--leaves questions regarding the adaptive and evolutionary effects of these processes. Analyzing deviations from Mendelian segregation offers an avenue for identifying loci targeted by GS and SEA, and their contributions to purging of genetic load. However, other selective processes such as meiotic drive and cytonuclear interactions, as well as pollen and ovule abortion, can cause distortion. To distinguish the effects of GS and SEA from other causes of distortion, we will perform reciprocal crosses between highly homozygous and highly heterozygous individuals …

Evaluation Of Inner Products Of Implicitly Defined Finite Element Functions On Multiply Connected Planar Mesh Cells, Jeffrey S. Ovall, Samuel E. Reynolds

Mathematics and Statistics Faculty Publications and Presentations

In recent years, there has been significant interest in the development of finite element methods defined on meshes that include rather general polytopes and curvilinear polygons. In the present work, we provide tools necessary to employ multiply connected mesh cells in planar domains, i.e., cells with holes, in finite element computations. Our focus is efficient evaluation of the ��1��1 semi-inner product and ��2��2 inner product of implicitly defined finite element functions of the types arising in boundary element based finite element methods and virtual element methods. Such functions are defined as solutions of Poisson problems having a polynomial source term …

Exhibiting The Museum: Interrogating Spaces Of Institutional Knowledge Production Through Interactive Print Design, Malcolm Church

University Honors Theses

This thesis explores the role of museums as active agents in the production of cultural and historical knowledge, focusing on the ethical implications of exhibition design and institutional practices. By examining the history of museums from ancient Greece to the modern era, with a focus on the Modern era, the research highlights how these institutions have perpetuated Eurocentric narratives and colonial ideologies through the collection and display of artifacts. Through interviews, participant observations, and historical analysis, this study uncovers the often-hidden decisions behind exhibition design and their impact on public perception. The culmination of this research is an interactive print …

Henna Chatbot Capstone Review, Kobe Norcross

University Honors Theses

This thesis reviews the development of the Henna Chatbot, an AI-powered DEI consultant designed to provide personalized feedback to organizations. Sponsored by DEI consultant Arsh Haque, the project aims to address gaps in current DEI software, which often lacks team-specific feedback. The Henna Chatbot leverages GPT-3.5 Turbo to create an affordable SaaS platform where organizations can train Henna with their DEI values, and Henna will help organizations stay aligned with those values. The project spanned twenty weeks and was completed by a team of eight computer science students at Portland State University. The development process followed Agile methodologies, emphasizing effective …

Capstone Review: Filament Unit Multiplexing Engine, Gal Cohen

University Honors Theses

The Filament Unit Multiplexing Engine (FUME) is a Mechanical Engineering capstone project sponsored by Portland State University's Electronic Prototyping Lab (EPL). The project addresses the need for an automated system to manage 3D printing operations. The current manual process of selecting and routing a spool of filament to one of the available 3D printers is labor-intensive and limits the efficiency of the lab's 3D printing farm. FUME aims to create a custom solution tailored for a multi-user, multi-spool, and multi-printer environment. The designed system includes key components: a spool holder, an engine, a track and shuttle system, and a funnel. …

How Different Modes Of Photosynthesis Impact Stormwater Runoff And Weed Growth On Ecoroof Trays During Early Establishment?, Michelle Hesek

University Honors Theses

Ecoroofs remove of stormwater runoff from the combined sewer system in Portland, Oregon. Reducing runoff is essential in cities considering how impervious surfaces promote flooding. A limited number of studies focus on comparing stormwater retention of ecoroof plants during their establishment period within Portland's climate. Different photosynthetic pathways in plants may impact stormwater runoff based on their water use efficiency. This study undertook a one-year study to determine the effect of plant establishment on water retention for a C4 and CAM species in six ecoroof trays. Weeds were investigated as a factor in water retention, and whether plant type within …

Climate Justice Issues, Urban Heat Island Effect, And Trees As The Solution In Portland, Oregon, Cleo Needham

University Honors Theses

Portland, Oregon, is experiencing rising temperatures caused by climate change and urban heat island effect. High heat disproportionately impacts vulnerable communities in Portland, causing harm to physical and mental health. Trees are a solution that reduces temperatures in urban environments. A strategy called 3-30-300 helps create a structure for where to place trees to help people receive the benefits. There are challenges with trees, such as the space required, the significant cost, and the time it takes to mature. Using trees as a solution can support and protect vulnerable communities in Portland, Oregon.

Modern Trail Of Tears: The Commodification Of First Foods And Medicines In Relation To Food Apartheid And Genocide Of Indigenous Peoples, Darius Mani Yaw

University Honors Theses

I am asking you to share in a cultural conversation with me. I will use different fonts in order to express my autobiographical and ethnographic Indigenous story separate from traditional academic writing This will not be a traditional thesis by any means of academic writing; this will also be a living document in a format of a cited reflection in order to continue the conversation not only through my Indigenous Research but also through community, and ideally will create everlasting solutions. However, this will be an introduction into my Indigenous writing and Indigenous voice.

I will be discussing the next …

Microplastic Pollution In Stormwater: Preliminary Findings From The Oregon Coast, Jazmine Compton

University Honors Theses

Microplastics have become ubiquitous in marine environments and pose a risk to ecosystem, organismal, and human health. Stormwater runoff has been suggested to be a major contributor to marine microplastic pollution. This project aims to quantify the average concentration of microplastics in stormwater in a community on the Oregon Coast. To accomplish this, stormwater samples were collected from five sites in Cannon Beach, Oregon, and one sample was analyzed using a dissection microscope. Using this technique, the number, size, and composition of the microplastic particles were determined. The calculated concentration of microplastics in the stormwater sample was 12.21 MPs/L, and …