Physical Sciences and Mathematics Commons^™

"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

The McDermitt Caldera, spanning from southeastern Oregon into northern Nevada, is believed to hold the largest lithium deposit in the United States. Actions have been swift to begin extraction in Nevada’s section of the Caldera. The construction of the Thacker Pass open-pit mine began in the spring of 2023, despite legal opposition from pan Indigenous groups, ranchers, and environmental groups. Across the border in Oregon, mining claims are scattered throughout the Caldera and exploratory drilling has begun. Given the early stage and rapid progression of these mining activities, there is a small but growing body of research regarding lithium mining …

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 …

Pt-Symmetry-Enabled Stable Modes In A Multicore Fiber, Tamara Gratcheva, Yogesh N. Joglekar, Jay Gopalakrishnan

Mathematics and Statistics Faculty Publications and Presentations

Open systems with balanced gain and loss, described by parity-time (PT -symmetric) Hamiltonians have been deeply explored over the past decade. Most explorations are limited to finite discrete models (in real or reciprocal spaces) or continuum problems in one dimension. As a result, these models do not leverage the complexity and variability of two-dimensional continuum problems on a compact support. Here, we investigate eigenvalues of the Schrödinger equation on a disk with zero boundary condition, in the presence of constant, PT -symmetric, gain-loss potential that is confined to two mirror-symmetric disks. We find a rich variety of exceptional points, re-entrant …

True Contraction Decomposition And Almost Eth-Tight Bipartization For Unit-Disk Graphs, Sayan Bandyapadhyay, William Lochet, Daniel Lokshtanov, Saket Saurabh, Jie Xue

Computer Science Faculty Publications and Presentations

We prove a structural theorem for unit-disk graphs, which (roughly) states that given a set D of n unit disks inducing a unit-disk graph ...

A Comparison Of Structure, Bonding And Non-Covalent Interactions Of Aryl Halide And Diarylhalonium Halogen-Bond Donors, Nicole Javaly, Theresa M. Mccormick, David R. Stuart

Chemistry Faculty Publications and Presentations

Halogen bonding permeates many areas of chemistry. A wide range of halogen-bond donors including neutral, cationic, monovalent, and hypervalent have been developed and studied. In this work we used density functional theory (DFT), natural bond orbital (NBO) theory, and quantum theory of atoms in molecules (QTAIM) to analyze aryl halogen-bond donors that are neutral, cationic, monovalent and hypervalent and in each series we include the halogens Cl, Br, I, and At. Within this diverse set of halogen-bond donors, we have found trends that relate halogen bond length with the van der Waals radii of the halogen and the non-covalent or …

Generalized Optimal Transport And Mean Field Control Problems For Reaction-Diffusion Systems With High-Order Finite Element Computation, Guosheng Fu, Stanley Osher, Will Pazner, Wuchen Li

Mathematics and Statistics Faculty Publications and Presentations

We design and compute a class of optimal control problems for reaction-diffusion systems. They form mean field control problems related to multi-density reaction-diffusion systems. To solve proposed optimal control problems numerically, we first apply high-order finite element methods to discretize the space-time domain and then solve the optimal control problem using augmented Lagrangian methods (ALG2). Numerical examples, including generalized optimal transport and mean field control problems between Gaussian distributions and image densities, demonstrate the effectiveness of the proposed modeling and computational methods for mean field control problems involving reaction-diffusion equations/systems.

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. …

Preperiodic Points Of Polynomial Dynamical Systems Over Finite Fields, Aaron Andersen, Derek Garton

Mathematics and Statistics Faculty Publications and Presentations

For a prime p, positive integers r,n, and a polynomial f with coefficients in Fpr, let Wp,r,n(f) = fn(Fpr) ∖ fn+1(Fpr). As n varies, the Wp,r,n(f) partition the set of strictly preperiodic points of the dynamical system induced by the action of f on Fpr. In this paper we compute statistics of strictly preperiodic points of dynamical systems induced by unicritical polynomials over finite fields by obtaining effective upper bounds for the proportion of Fpr lying in a given Wp,r,n(f). Moreover, when we generalize our definition of Wp,r,n(f), we obtain both upper and lower bounds for the resulting averages.

Mechanistic Rationale For Ketene Formation During Dabbing And Vaping, Kaelas R. Munger, Killian M. Anreise, Robert P. Jensen, David H. Peyton, Robert M. Strongin

Chemistry Faculty Publications and Presentations

Ketene is one of the most toxic vaping emissions identified to date. However, its high reactivity renders it relatively challenging to identify. In addition, certain theoretical studies have shown that realistic vaping temperature settings may betoo low to produce ketene. Each of these issues is addressed herein. First, an isotopically labeled acetate precursor is used for the identification of ketene with enhanced rigor in vaped aerosols. Second, discrepancies between theoretical and experimental findings are explained by accounting for the effects of aerobic (experimental) versus anaerobic (simulated and theoretical) pyrolysis conditions. This finding is also relevant to explaining the relatively low-temperature …

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 …

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' …

Examining The Interaction Between Calcium Supplement Use, Demographics, And Lifestyle Factors On Bone Health In Women, Vix Talbot

University Honors Theses

Osteoporosis is a condition which poses a significant health threat, particularly among women during the menopause transition, where accelerated bone loss increases fracture risk. Calcium supplementation has been shown to be an important intervention to mitigate bone mineral density (BMD) decline during this and other periods of life. However, the efficacy of calcium supplementation is influenced by various individual factors, including demographics and lifestyle habits. This study investigates the interaction between calcium supplement use, and several interaction terms on bone health in women. Multiple linear regression analysis is employed to assess the impact of these factors on BMD. Data from …

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 …

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.

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 …

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 …

Piloting A Drain Gauge As A Method Of Measuring Runoff From Ecoroofs In Portland, Trinity Perrin

University Honors Theses

The following paper will be exploring a pilot methodology of a drain gauge system I built that’s used to calculate stormwater runoff from ecoroofs in Portland, Oregon. The drain gauge is a less studied technique for measuring ecoroof runoff, but holds high potential for developing better monitoring and management of ecoroofs within the city of Portland. What separates this stormwater runoff capturing device apart from other stormwater runoff calculation techniques is its adaptable design and simple installation. The drain weir can be placed in any roof drain that an ecoroof has been installed simply by placing it into a roof …

Cards With Class: Formalizing A Simplified Collectible Card Game, Dan Ha

University Honors Theses

Collectible card games (CCGs) have been a wildly popular game genre since the release of Wizards of the Coast's Magic: The Gathering. These games revolve around their thousands of cards and the hundreds of thousands of interactions they can create with their many effects. For designers, it is an incredibly demanding task to ensure that every single card works properly and that each card's text unambiguously conveys its intended behavior in all cases. The task only grows more difficult over time as the number of cards in the game grows and card effects become more complex or experimental. If the …

Scale-Dependent Effects Of Urban Canopy Cover, Canopy Volume, And Impervious Surfaces On Near Surface Air Temperature In Portland, Or, Carson Ralls

Geography Masters Research Papers

Cities are significantly warmer than their surrounding rural environments. Known as the ‘urban heat island effect’, it can affect the health of urban residents and lead to increased energy use. Although this effect is extensively researched, less is known about how landscape characteristics within cities affect local temperature variation. With a warming climate and the need for heat mitigation strategies becoming more urgent, having a finer detailed understanding of the effects on temperature is critical to guide proper management policies. This study examined how tree canopy cover, canopy volume, and impervious surface cover affect daytime near surface air temperature, and …

The Institutional Challenges Of A Quantified Self Study: An Attempt To Ascertain How Data Collected From A Mobile Device Can Be An Indicator Of Personal Mental Health Over Time, Julian Lazaras

University Honors Theses

The adoption of an application of new technology always comes with a bias, this is never more true for the case of human behavioral analytics within higher education. While movements such as the quantified self movement make strides to reinterpret the realm of data analytics, psychology, and computer science, there are inevitably limitations to the adoption and application of such approaches within the standard realm of research. Herein is presented a case where an effort to evaluate the prospect of use of mobile phone data as secondary indicators of personal mental health through the lens of data analysis was put …

Mapping Mental Models Through An Improved Method For Identifying Causal Structures In Qualitative Data, Erin S. Kenzie, Wayne Wakeland, Antonie Jetter, Kristen Hassmiller Lich, Mellodie Seater, Melinda M. Davis

Complex Systems Faculty Publications and Presentations

Qualitative data are commonly used in the development of system dynamicsmodels, but methods for systematically identifying causal structures in qualita-tive data have not been widely established. This article presents a modifiedprocess for identifying causal structures (e.g., feedback loops) that are commu-nicated implicitly or explicitly and utilizes software to make coding, tracking,and model rendering more efficient. This approach draws from existingmethods, system dynamics best practice, and qualitative data analysis tech-niques. Steps of this method are presented along with a description of causalstructures for an audience new to system dynamics. The method is applied to aset of interviews describing mental models of …

Complete Genome Sequence Of Strain Jm503a, A Genetically Tractable Dental Abscess Clinical Isolate, Dustin L. Higashi, Anh Nguyen, Hua Qin, Christina Borland, Elizabeth A. Palmer, Nicolas Biais, Jens Kreth, Justin Merritt

Chemistry Faculty Publications and Presentations

Parvimonas micra is a pathobiont of humans that is often found in abundance at sites of mucosal inflammation as well as within malignant tumors. Here, we report the complete genome sequence of P. micra strain JM503A, which is a genetically tractable clinical isolate derived from a human odontogenic abscess specimen.

Embodied Urban Political Ecology Of Oil: Social Reproduction In Oil ‎Geographies Case Study: Ahwaz, Khuzestan, Iran, Maryam Amiri

Dissertations and Theses

This dissertation examines the transformative impact of the oil industry on social ‎reproduction ‎‎within the urban and ecological landscapes of Khuzestan Province, Iran, and ‎its center, the city ‎of Ahwaz. Specifically, the study sought to understand the effects of ‎the oil industry on social ‎reproduction in three key areas: gender relations, race/ethnic ‎relations, and daily life ‎amidst ‎environmental pollution caused by the oil industry.

‎This is explored through three sub-questions: 1) How are hierarchical socio-‎spatial ‎relationships perpetuated through practices of ‎everyday life? 2) How are gender ‎relationships redefined and ‎reproduced in the oil city? 3) How ‎are ethnic relationships ‎redefined …

Resource-Constrained 2d Scene Recovery With Single-Photon Cameras, Daphne Ariadne Kurzenhauser

Dissertations and Theses

The modern world is built of images. However, in our goal to photograph and replicate what the human eye is capable of seeing, we are throttled by the restrictions of conventional imaging sensors in high- and low-illumination environments. Single-photon cameras (SPCs) have recently emerged as a promising alternative to conventional camera sensors for capturing images in challenging conditions such as high-dynamic range and fast scene motion. Compared to traditional CMOS cameras, SPCs exploit the arrival of individual photons rather than using an aggregate photon count to compute the brightness of pixels. However, SPCs are extremely resource-intensive, making them inconvenient for …

Artificial Intelligence As The Next Front In The Class War, Christopher Hill

Dissertations and Theses

For many years, artificial intelligence has been confined to the realm of science fiction, and while the technology has been in development, predicting the effects AI will have on our society has been a challenging endeavor. The release of ChatGPT in 2022, the subsequent mass adoption of the AI chatbot, and the response by other private firms in the field announced AI's permanent entrance into the public sphere. These recent strides made in the field of artificial intelligence reveal that the pace of technological development has outstripped the rate at which we are able to politically examine and understand these …

Yang-Baxter Equations, David Lovitz

Dissertations and Theses

Multiple equations in math, physics, quantum information, and elsewhere are referred to as "the" Yang-Baxter equation, in spite of being a broad family of equations. Most of the equations are nonlinear matrix equations, where the unknown variable is a matrix. This is the case for the so called braided, algebraic, and generalized forms of "the" equation, which are the primary focus of this dissertation. Finding solutions to the various forms of these equations has been the subject of much research. The equations in all their forms are largely considered intractable in high dimensions, and only in dimension 2 have the …

Dft Based Modeling Of The Heavy Atom Effect In Triplet Photosensitizers: From Fundamental Mechanics To Rational Design, Bret Andrew Steinkamp

Dissertations and Theses

Photochemistry is the study of how light interacts with molecules and includes both the absorption and release of light. This document focuses on triplet photosensitizers -- molecules that utilize the excited triplet state -- for a variety of applications including photodynamic therapy and photocatalysis. There are many factors that influence the design of triplet photosensitizers; in this work, we have developed and used a methodology for the rational design of triplet photosensitizers based on an approximation of the heavy atom effect (HAE) from density functional theory calculations and the experimentally measured singlet oxygen quantum yield (Ф_Δ).

As excited …

Matching The Scales Of Planning And Environmental Risk: An Evaluation Of Community Wildfire Protection Plans In The Western Us, Matthew Hamilton, Cody Evers, Max Nielsen-Pincus, Alan A. Ager

Environmental Science and Management Faculty Publications and Presentations

Theory predicts that effective environmental governance requires that the scales of management account for the scales of environmental processes. A good example is community wildfire protection planning. Plan boundaries that are too narrowly defined may miss sources of wildfire risk originating at larger geographic scales whereas boundaries that are too broadly defined dilute resources. Although the concept of scale (mis)matches is widely discussed in literature on risk mitigation as well as environmental governance more generally, rarely has the concept been rigorously quantified. We introduce methods to address this limitation, and we apply our approach to assess scale matching among Community …

An Index Of Biotic Integrity For Macroinvertebrate Stream Bioassessment Conducted By Community Scientists, Patrick M. Edwards, Daniel Bedell, Shannon Hubler, Chad A. Larson, Kate H. Macneale, Elisa Mickelson, Chris Prescott, Elinore Webb, Jo Wilhelm

Environmental Science and Management Faculty Publications and Presentations

Community science bioassessment has great potential to inform comprehensive stream management plans, but regional analytical tools are needed to evaluate macroinvertebrate data collected through community science programs. To this end, we modified a pre-existing professional index of biotic integrity (IBI) to create a community science IBI (CS-IBI), designed for stream macroinvertebrate data collected by community scientists with minimal training. We used data collected by both professional and community scientists to develop, calibrate, and validate the CS-IBI at 76 streamsites in the Puget Lowland andWillamette Valley ecoregions of the PacificNorthwest in theUnited States. Community science data were taxonomically coarser andmore variable …

Virtual Field Environments Capstone Software Review, Ashton Sawyer

University Honors Theses

This is a review of the Virtual Field Environments computer science capstone project, sponsored by geology professor Rick Hugo. The tool aims to create and render VFEs, interactable 360° environments hosted on the web that are used as virtual field trips for K-12 students. This essay discusses the development process, including understanding requirements, tool and technology selection, problem-solving, and decision-making strategies. It also highlights the differences between the capstone and the other core computer science courses, and how those differences help to prepare students for the workforce. The project was completed over the course of twenty weeks by a team …