Physical Sciences and Mathematics Commons^™

Numerical Techniques And Simulations For Studying Various High Power Optical Fiber Amplifiers, Particularly For Ytterbium (Yb+3), And Thulium (Tm+3) Doped Fibers, Tathagata Goswami

Dissertations and Theses

In this dissertation we present a simplified scalar numerical model, derived from Maxwell's field equations, for the fiber laser amplifier simulations. Maxwell's equations are reduced using a technique called Coupled Mode Theory (CMT).

The reduced model is made more efficient through a new scale model, referred to as an equivalent short fiber, which captures some of the essential characteristics of a longer fiber. The equivalent short fiber can be viewed as a fiber made using artificial (nonphysical) material properties that in some sense compensates for its reduced length. The computations can be accelerated by a factor approximately equal to the …

A Method For Comparative Analysis Of Trusted Execution Environments, Stephano Cetola

Dissertations and Theses

The problem of secure remote computation has become a serious concern of hardware manufacturers and software developers alike. Trusted Execution Environments (TEEs) are a solution to the problem of secure remote computation in applications ranging from "chip and pin" financial transactions to intellectual property protection in modern gaming systems. While extensive literature has been published about many of these technologies, there exists no current model for comparing TEEs. This thesis provides hardware architects and designers with a set of tools for comparing TEEs. I do so by examining several properties of a TEE and comparing their implementations in several technologies. …

A Community Of Fear: Emotion And The Hydro-Social Cycle In East Porterville, Michael Egge

Geography Masters Research Papers

Broader governance challenges driving water insecurity globally are well documented in the literature, however the power-laden relationships and emotions that shape water access at the household and community levels are yet to be fully investigated, especially in the context of water consolidation projects. In this article, we examine the role of emotions in mediating access to water and in the production of resource struggles among marginalized communities existing outside of conventional regulatory frameworks. We bring together two relational approaches – the hydro-social cycle and emotional political ecology – to examine water insecurity and how it manifests in the historically disadvantaged …

Tellurorhodamine Photocatalysts In Aerobic Oxidation Reactions: Development Of Synthetic Methods And Reaction Mechanisms, Irving D. Rettig

Dissertations and Theses

Aerobic oxidation photocatalysis involves the use of oxygen as an oxidant species, coupled to a light driven catalyst to achieve useful chemical transformations. Catalytic aerobic oxidation reactions can be defined as either oxidase-like, in which O₂ acts as an electron donor/acceptor but is not incorporated into the reaction products, or oxygenase-like where O₂ acts as an electron donor/acceptor and is incorporated into the reaction products. A multitude of inorganic catalysts have been developed that can achieve a wide scope of oxidase-like or oxygenase-like reactivity, however, it is rare for a catalyst to be capable of both. We report …

Investigations Into Size And Surface Control Of Silicon Nanocrystals For Improved Optical Properties, James Donald Barnes

Dissertations and Theses

The discovery of visible photoluminescence (PL) from nanocrystalline porous silicon in 1990 led to extensive research into the mechanisms of the emergent properties, and optimization of these properties, for use in applications. The widespread use of silicon nanoparticles (Si NPs) in commercial applications is currently limited by three main factors: 1) poor radiative recombination efficiency of the interband transition, 2) instability of the interband photoluminescence, and 3) a lack of scalable methods for producing Si NPs that are both highly crystalline and size monodisperse.

To address these limitations, this dissertation correlates changes in the photoluminescence properties of hydrogen passivated silicon …

Understory Species Increase Project: Investigating The Revegetation Of Native Herbaceous Species From Seed In Urban Forest Fragments, Erin Mcelroy

Environmental Science and Management Professional Master's Project Reports

Management of urban forest fragments often aims to reduce invasive species and promote native species abundance and diversity. Often, these environments lack natural establishment of native forest species, including herbaceous species that are especially sensitive to site conditions. While herbaceous understory species may represent a small proportion of forest biomass, they perform important functions within forest environments, including nutrient cycling, erosion and runoff control, and providing habitat for wildlife, as well as hosting the greatest biodiversity among other forest strata. However, many restoration projects focus primarily on the revegetation of dominant woody forest species, such as hardwood trees and shrubs. …

The Spatial And Temporal Evolution Of The Portland And Tualatin Forearc Basins, Oregon, Usa, Darby P. Scanlon, John Bershaw, Ray E. Wells, Ashley R. Streig

Geology Faculty Publications and Presentations

The Portland and Tualatin basins are part of the Salish-Puget-Willamette Lowland, a 900-km-long, forearc depression lying between the volcanic arc and the Coast Ranges of the Cascadia convergent margin. Such inland seaways are characteristic of warm, young slab subduction. We analyzed the basins to better understand their evolution and relation to Coast Range history and to provide an improved tectonic framework for the Portland metropolitan area. We model three key horizons in the basins: (1) the top of the Columbia River Basalt Group (CRBG), (2) the bottom of the CRBG, and (3) the top of Eocene basement. Isochore maps constrain …

Multilevel Hierarchical Decomposition Of Finite Element White Noise With Application To Multilevel Markov Chain Monte Carlo, Hillary R. Fairbanks, Umberto E. Villa, Panayot S. Vassilevski

Mathematics and Statistics Faculty Publications and Presentations

In this work we develop a new hierarchical multilevel approach to generate Gaussian random field realizations in an algorithmically scalable manner that is well suited to incorporating into multilevel Markov chain Monte Carlo (MCMC) algorithms. This approach builds off of other partial differential equation (PDE) approaches for generating Gaussian random field realizations; in particular, a single field realization may be formed by solving a reaction-diffusion PDE with a spatial white noise source function as the right-hand side. While these approaches have been explored to accelerate forward uncertainty quantification tasks, e.g., multilevel Monte Carlo, the previous constructions are not directly applicable …

Economic Valuation Of Ecosystem Services Provided By Forest Ecosystems In Sri Lanka: A Study Based On 2010 Forest Cover Classification And The Teeb Database, Isuru Jayantha Alawaththa Kankanamge

Environmental Science and Management Professional Master's Project Reports

Ecosystem service valuation is becoming popular among the economists, ecologists, scientists and policy makers. As a result, various research, publications and programs have arisen and content of literature is developed rapidly. Even though this field of study is developing rapidly, Sri Lankan ecosystems have not yet been valued or evaluated yet in terms of economic returns. Hence, the main purpose of this study is to calculate and define economic value for each forest polygon of 2010 forest cover data base by using the value transferring approach. This data base will be an effective tool to have a fair cost-benefits analyses …

Influence Of Climate Change On Forest Fire Occurrence And Distribution Of Sri Lanka And Modeling Of Forest Fire, Mohan Heenatigala

Environmental Science and Management Professional Master's Project Reports

Forest fire is one of the main causes for forest degradation and deforestation which affect ecosystem services provided by the given landscapes. Weather variables like temperature, wind speed and direction, rainfall, and relative humidity also govern the forest fire regime and vulnerability. On the other hand, forest fuel characteristics, human impacts, population density, forest canopy density, slope, elevation, road density, closeness to the human settlement areas are other factors that determine the forest fire impact and potential of damage. Annually, 100 to 2500 hectares of forest resources are damaged due to forest fires in Sri Lanka. From the past few …

Current Stormwater Practices And Future Implementation At Portland State University With The Uncertainty Of Climate Change, Evan Suemori, Alexandra Vargas Quiñones

Environmental Science and Management Professional Master's Project Reports

Stormwater runoff is one of the most critical environmental issues in urban areas and is only expected to worsen as climate change persists (EPA, 2016). When precipitation events occur, stormwater travels across impervious surfaces collecting soils and pollutants which can negatively impact water quality in receiving waters. Additionally, stormwater has human health impacts, specifically through flooding and the contamination of drinking water. According to the Intergovernmental Panel on Climate Change (IPCC), it has been determined that climate change will increase the frequency, intensity, and/or number of precipitation events in some regions, including the Pacific Northwest, and decrease in others (IPCC, …

Agency, Sense Of Place, And Knowledge On The Zumwalt Prairie: A Social Study Of Place-Based Conservation And Resilience, Dana Elyse Hellman

Dissertations and Theses

Shifting and often diminishing environmental conditions, due to climate change, resource loss, and ecosystem degradation, pose a significant concern to both social and ecological systems. The field of conservation science has attempted to address environmental threats through varying approaches, transitioning from fortress conservation and complete human exclusion to community-based and co-managed models which incorporate human actors and social dimensions in the conservation process. The latest iteration of conservation scholarship, place-based conservation, is deeply rooted in interdisciplinary, social scientific thinking, and calls for significant practitioner engagement with local knowledge, practices, social constructions, and place meanings. It is an approach which emphasizes …

Photoemission Electron Microscopy For Direct Observation Of Photonic And Plasmonic Phenomena, Theodore Stenmark

Dissertations and Theses

Photoemission electron microscopy (PEEM) is a high-resolution microscopy technique that collects photoemitted electrons from the sample surface to form an image. PEEM offers a non-scanning imaging method with a spatial resolution in the range of 5-100nm by combining the advantages of light excitation and electron imaging. Our work looks at PEEM as an analysis tool for photonic and plasmonic phenomena. Photonic wave guiding structures exhibiting a strong dispersion relation have attracted considerable attention for applications in integrated optics, communications and sensing devices. Line defects in a photonic crystal (PC) slab offer a highly efficient way to create light with group …

Urban Lakes: Ecosystem Services And Management, Laura Costadone

Dissertations and Theses

Lakes provide a variety of ecosystem services and benefits that greatly contribute to urban sustainability. Despite the growing interest in integrating freshwater systems into management and policy decisions, urban lakes are often overlooked in land-use planning. Nutrient and pollutant runoff from the surrounding urbanized watershed result in water quality deterioration that negatively impact the lake ecological functions and related ecosystem services. The vulnerability and degradation of these urban ecosystems should be a matter of concern, especially considering that, in rapidly growing metropolitan areas, the demand for aesthetic and recreational services provided by urban lakes is increasing. The overall goal of …

Steady-State Transmembrane Water Exchange In Proliferating Cultures Of Saccharomyces Cerevisiae, Joseph O'Malley Armstrong

Dissertations and Theses

Cellular water exchange is often considered in terms of a change in volume, where a net flux of water moves across the cell membrane due to a change in osmotic pressure. Osmotic pressure can cause a cell to shrink or swell, however, rapid water exchange persists across the membrane even when the volume of the cell is constant. Steady-state transmembrane water exchange describes the exchange of water across the cell membranes which results in no net change in cell volume. This exchange is astonishingly rapid; the entire pool of intracellular water of a Saccharomyces cerevisiae cell may exchange 2-5 times …

Chemical Characterization Of Toxicologically Relevant Molecules In Cannabis Concentrates And Vaporizer Aerosols, Jiries Meehan-Atrash

Dissertations and Theses

Consumption of cannabis concentrates using the relatively novel non-combustion methods dabbing and vaping has steadily grown in popularity as cannabis legalization in North America has allowed increased access to sophisticated cannabis products and technology. In order to assess the safety of these products, it is necessary to gain a chemical understanding of the decomposition reactions that occur when the active ingredients are heated in the conditions seen when dabbing or vaping. This dissertation contains a manuscript that details efforts to structurally characterize a toxic cannabis concentrate adulterant, and three manuscripts that studied the chemical decomposition of the two primary cannabis …

Supporting Biomedical Research Training For Historically Underrepresented Undergraduates Using Interprofessional, Nonformal Education Structures, Lisa K. Marriott, Aaron Raz Link, Roberto P. Anitori, Ernest A. Blackwell, Andrea Blas, Jennifer Brock, Tracey K. Burke, Julia A. Burrows, Alexis P. Cabrera, Derek Helsham, Lorna B. Liban, Marilyn R. Mackiewicz, Mika Maruyama, Kathryn C.A. Milligan-Myhre, Perry J.C. Panelinan, Margaret Hattori-Uchima, Russell Reed, Ben E. Simon, Beylul Solomon, Alma M.O. Trinidad, Letisha R. Wyatt, Alonso Delgado Covarrubias, Adrienne Zell, Thomas E. Keller, Cynthia Morris, Carlos J. Crespo

Chemistry Faculty Publications and Presentations

Research experience provides critical training for new biomedical research scientists. Students from underrepresented populations studying science, technology, engineering, and mathematics (STEM) are increasingly recruited into research pathways to diversify STEM fields. However, support structures outside of research settings designed to help these students navigate biomedical research pathways are not always available; nor are program support components outside the context of laboratory technical skills training and formal mentorship well understood. This study leveraged a multi-institutional research training program, Enhancing Cross-Disciplinary Infrastructure and Training at Oregon (EXITO), to explore how nine institutions designed a new curricular structure (Enrichment) to meet a common …

Storing Intermediate Results In Space And Time: Sql Graphs And Block Referencing, Basem Ibrahim Elazzabi

Dissertations and Theses

With the advancement of data-collection technology and with more data being available for data analysts for data-intensive decision making, many data analysts use client-based data-analysis environments to analyze that data. Client-based environments where only a personal computer or a laptop is used to perform data analysis tasks are common. In such client-based environments, multiple tools and systems are typically needed to accomplish data-analysis tasks. Stand-alone systems such as spreadsheets, R, Matlab, and Tableau are usually easy to use, and they are designed for the typical, non-technical data analyst. However, these systems are limited in their data-analysis capabilities. More complex data …

Anti-Inflammatory And Immunomodulatory Properties Of Fermsented Plant Food, Roghayeh Shahbazi, Farzaneh Sharifzad, Rana Bagheri, Nawal Alsadi, Hamed Yasavoli-Sharahi, Chantal Matar

Chemistry Faculty Publications and Presentations

Fermented plant foods are gaining wide interest worldwide as healthy foods due to their unique sensory features and their health-promoting potentials, such as antiobesity, antidiabetic, antihypertensive, and anticarcinogenic activities. Many fermented foods are a rich source of nutrients, phytochemicals, bioactive compounds, and probiotic microbes. The excellent biological activities of these functional foods, such as anti-inflammatory and immunomodulatory functions, are widely attributable to their high antioxidant content and lactic acid-producing bacteria (LAB). LAB contribute to the maintenance of a healthy gut microbiota composition and improvement of local and systemic immunity. Besides, antioxidant compounds are involved in several functional properties of fermented …

A Golden Age For Computing Frontiers, A Dark Age For Computing Education?, Christof Teuscher

Electrical and Computer Engineering Faculty Publications and Presentations

There is no doubt that the body of knowledge spanned by the computing disciplines has gone through an unprecedented expansion, both in depth and breadth, over the last century. In this position paper, we argue that this expansion has led to a crisis in computing education: quite literally the vast majority of the topics of interest of this conference are not taught at the undergraduate level and most graduate courses will only scratch the surface of a few selected topics. But alas, industry is increasingly expecting students to be familiar with emerging topics, such as neuromorphic, probabilistic, and quantum computing, …

From Molecules To Mountains: A Multi-Proxy Investigation Into Ancient Climate And Topography Of The Pacific Northwest, Usa, Alex Mclean

Dissertations and Theses

The modern Cascades are a north-south striking mountain range that intercepts Pacific Ocean-derived moisture resulting in orographic precipitation on the western flank and a relatively arid rain shadow in the lee. Because of the strong coupling between topography and climate and consistent moisture source (Pacific Ocean) throughout the year, the region is ideally situated for paleoclimate studies that utilize the isotopic composition (δ¹⁸O and δD) of meteoric water to determine when uplifts occurred. Here, I synthesize the spatial and temporal evolution of stable isotopes in paleowater proxies across the Pacific Northwest during the Cenozoic. New volcanic glass (δD) …

Using Information Theory To Extract Patterns From Categorical Raster Data, David Percy

Systems Science Faculty Publications and Presentations

Information theory -- Reconstructability Analysis (RA) implemented in the Occam software -- was used to extract patterns from National Land Cover Data. The aim was to predict temporal change in evergreen forests from time-lagged and spatially adjacent states. The NLCD satellite data were preprocessed with Python and submitted to Occam for analysis, and Occam output was also explored with R-studio. The effectiveness of RA methodology for the analysis of this type of categorical space-time grid data was demonstrated.

The Use Of Mayflies, Stoneflies And Caddisflies As Indicators Of Fine Sediment Pollution In Salmon-Bearing Streams Of The Pacific Northwest, Cory Michael Mccaffrey

Dissertations and Theses

Fine sediment (particles < 2 mm in diameter) deposition is a natural component of streams but in excess amounts it is harmful to aquatic biota. Fine sediment is the main cause of impairment in streams and rivers of the Pacific Northwest and it can lead to unsuitable spawning and rearing habitat for Endangered Species Act (ESA) listed Salmon and steelhead. From a regulatory perspective, fine sediment presents a challenge because it is difficult to measure in situ and to establish criteria that would indicate stream impairment. Consequently, there is considerable effort to develop biocriteria using stream macroinvertebrates that would help regulators determine if a stream is impaired by excessive fine sediment.

Stream macroinvertebrates are widely used to monitor and assess stream degradation because they are affected by the physical, chemical and biological conditions in a stream. In particular, the stream insects known as mayflies (Ephemeroptera, E), stoneflies (Plecoptera, P) and caddisflies (Trichoptera, T) are commonly used as a metric referred to as EPT richness. EPT taxa are well known as pollutant intolerant …

Climatic Controls On The Kinematics Of The Hooskanaden Landslide, Curry County, Oregon, Kara Kingen

Dissertations and Theses

Slow-moving earthflows represent major sources of sediment transport and erosion and are problematic for the management of critical infrastructure. The Hooskanaden Landslide -- a slow-moving earthflow on the southwest coast of Oregon -- crosses US Highway 101 and has been a site of continued interest to the Oregon Department of Transportation (ODOT) due to the weak lithology, erosive environment, and recurrent surge behavior (every ~15 years). Past surges, including the most recent (2019), have occurred during the winter, suggesting that velocity changes are predominantly controlled by climatic inputs. To examine the response of the Hooskanaden Landslide to seasonal and other …

Fluorogenic Probes For Thioredoxin Reductase Activity, Tendai J. Mafireyi, Jorge O. Escobedo, Robert Strongin

Chemistry Faculty Publications and Presentations

The thioredoxin system is vital in maintaining the cellular redox state and is implicated in various cancers and other diseases. It comprises of thioredoxin reductase, thioredoxin and NADPH. Various methods have been developed for the detection and quantification of the thioredoxin reductase enzyme. Most of these methods suffer the shortfall of poor specificity, hence there is need to develop more robust and specific techniques. Recently, there has been an increased interest in fluorescent probes that can target thioredoxin reductase. This review highlights the progress in the synthesis and application of the different fluorescent probes that have been employed for this …

The Amungme And The Environment: Environmental Justice History And Consumerism, Kole A. Dawson

Phi Alpha Theta Pacific Northwest Regional Conference

The Amungme are one of hundreds of Papuan people groups who lived in the Indonesian province in New Guinea for thousands of years. This group subsisted in their environment by hunting, cultivation of small crops, and practicing pig husbandry. In the late 1960s, seeking foreign capital to boost the nation’s economy, the president of Indonesia signed a contract with Freeport McMoRan Copper and Gold. Freeport began mining in the early 1970s, eventually opening one of the world’s largest gold mines. Excavating sacred Amungme sites, Freeport’s massive pollution to the land and water destroyed the indigenous people’s environment both spiritually and …

Glaciers Of The Olympic Mountains, Washington - The Past And Future 100 Years, Andrew G. Fountain, Christina Gray, Bryce Allen Glenn, Brian Menounos, Justin Pflug, Jon L. Riedel

Geology Faculty Publications and Presentations

In 2015, the Olympic Mountains contain 255 glaciers and perennial snowfields totaling 25.34 ± 0.27 km², half of the area in 1900, and about 0.75 ± 0.19 km³ of ice. Since 1980, glaciers shrank at a rate of -0.59 km² yr^-1 during which 35 glaciers and 16 perennial snowfields disappeared. Area changes of Blue Glacier, the largest glacier in the study region, was a good proxy for glacier change of the entire region. A simple mass balance model of the glacier, based on monthly air temperature and precipitation, correlates with glacier area change. The mass …

Networking Frameworks: A Method For Analyzing The Complexities Of Classroom Cultures Focusing On Justifying, Eva Thanheiser, Kathleen Melhuish, Amanda Sugimoto, Brenda Rosencrans, Ruth Heaton

Mathematics and Statistics Faculty Publications and Presentations

In this paper, we network five frameworks (cognitive demand, lesson cohesion, cognitive engagement, collective argumentation, and student contribution) for an analytic approach that allows us to present a more holistic picture of classrooms which engage students in justifying. We network these frameworks around the edges of the instructional triangle as a means to coordinate them to illustrate the observable relationships among teacher, students(s), and content. We illustrate the potential of integrating these frameworks via analysis of two lessons that, while sharing surface level similarities, are profoundly different when considering the complexities of a classroom focused on justifying. We found that …

Posterior Predictive Critique Of A Psychometric Bayesian Model For Assessing Aphasia, Ashlynn Crisp

Mathematics and Statistics Dissertations, Theses, and Final Project Papers

For persons with aphasia, naming tests are useful for assessing the severity of the disease and observing progress toward recovery. The Philadelphia Naming Test (PNT) is a leading naming test composed of 175 items. The items are common nouns which are one to four syllables in length and with low, medium, and high frequency. Since the target word is known to the administrator, the response from the patient can be classified as correct or an error. If the patient commits an error, the PNT provides procedures for classifying the type of error in the response. Item response theory can be …

Community Engagement In Oregon Water Governance: Evaluating A State Water Policy And A Collaborative Q Methodology Research Project, Clare T. Mcclellan

Environmental Science and Management Professional Master's Project Reports

This work was primarily conducted by the Oregon Water Stories Project, an interdisciplinary research group at Portland State University, in collaboration with the Willamette Partnership, an environmental non-profit in Portland, and with additional involvement from community partner organizations across the state. The overarching goal of this paper is to explore the challenges and opportunities present at the intersections of water management, stakeholder engagement, community-engaged research, and environmental justice. This study investigates this nexus first through an evaluation of Oregon’s 100 Year Water Vision that points to areas for increased integration of environmental justice principles in water policymaking. In the second …