Physical Sciences and Mathematics Commons^™

Investigation Of The Acoustic Response Of A Confined Mesoscopic Water Film Utilizing A Combined Atomic Force Microscope And Shear Force Microscope Technique, Monte Allen Kozell

Dissertations and Theses

An atomic force microscopy beam-like cantilever is combined with an electrical tuning fork to form a shear force probe that is capable of generating an acoustic response from the mesoscopic water layer under ambient conditions while simultaneously monitoring force applied in the normal direction and the electrical response of the tuning fork shear force probe. Two shear force probes were designed and fabricated. A gallium ion beam was used to deposit carbon as a probe material. The carbon probe material was characterized using energy dispersive x-ray spectroscopy and scanning transmission electron microscopy. The probes were experimentally validated by demonstrating the …

Epa-Rimm-V: Efficient Rootkit Detection For Virtualized Environments, Tejaswini Ajay Vibhute

Dissertations and Theses

The use of virtualized environments continues to grow for efficient utilization of the available compute resources. Hypervisors virtualize the underlying hardware resources and allow multiple Operating Systems to run simultaneously on the same infrastructure. Since the hypervisor is installed at a higher privilege level than the Operating Systems in the software stack it is vulnerable to rootkits that can modify the environment to gain control, crash the system and even steal sensitive information. Thus, runtime integrity measurement of the hypervisor is essential. The currently proposed solutions achieve the goal by relying either partially or entirely on the features of the …

Moving Beyond Alpha: A Primer On Alternative Sources Of Single-Administration Reliability Evidence For Quantitative Chemistry Education Research, Regis Komperda, Thomas C. Pentecost, Jack Barbera

Chemistry Faculty Publications and Presentations

This methodological paper examines current conceptions of reliability in chemistry education research (CER) and provides recommendations for moving beyond the current reliance on reporting coefficient alpha (α) as reliability evidence without regard to its appropriateness for the research context. To help foster a better understanding of reliability and the assumptions that underlie reliability coefficients, reliability is first described from a conceptual framework, drawing on examples from measurement in the physical sciences; then classical test theory is used to frame a discussion of how reliability evidence for psychometric measurements is commonly examined in CER, primarily in the form of single-administration reliability …

Volcanic Glass As A Paleoenvironmental Proxy: Comparing Preparation Methods On Ashes From The Lee Of The Cascade Range In Oregon, Usa, Tessa Boe Carlson

Dissertations and Theses

Deuterium ratios (δD) of hydrated volcanic glass have been used to reconstruct paleoenvironments, although the reliability and proper sample preparation protocol have been debated. In this study, hydrated volcanic ash samples from the lee of the Cascades were prepared using two separate methods. Method 1 involves sonicating and rinsing samples with hydrochloric acid (HCl) followed by hand-selection of glass shards (125-212µm). Method 2 requires hydrochloric acid (HCl) and hydrofluoric acid (HF) abrasion as well as heavy liquid separation of shards (70-150µm). Method 2 produced more consistent results with decreased intra-replicate variability in both water content (-0.92 wt. %) and deuterium …

Mooring Impacts On Zostera Marina Meadows And Associated Epifauna In Nantucket Harbor, Massachusetts, Usa, Andrew Wright Mccandless

Dissertations and Theses

Seagrass ecosystems are some of the most productive in the world and provide a variety of ecosystem services but are facing global decline chiefly due to anthropogenic disturbance. Mechanical disturbances to seagrass meadows from anchoring, propeller scars, and mooring scars result in losses or damage to both shoots and the underlying rhizome. I conducted a literature synthesis on the extent of, recovery from, and ecological impacts of these mechanical disturbances to seagrass meadows. The literature suggests that anchoring damage tends to be worst in deeper water where larger vessels anchor and can cause large (>100m²) loss per …

Electro-Drop Bouncing In Low-Gravity, Erin Stivers Schmidt

Dissertations and Theses

We investigate the dynamics of spontaneous jumps of water drops from electrically charged superhydrophobic dielectric substrates during a sudden step reduction in gravity level. In the brief free-fall environment of a drop tower, with a non-homogeneous external electric field arising due to dielectric surface charges (with surface potentials 0.4-1.8 kV), body forces acting on the jumped drops are primarily supplied by polarization stress and Coulombic attraction instead of gravity. This electric body force leads to a drop bouncing behavior similar to well-known phenomena in 1-g₀, though occurring for much larger drops (~0.5 mL). We show a simple …

Effects Of Substrate Depth And Precipitation Characteristics On Stormwater Retention By Two Green Roofs In Portland Or, Isaac Schultz, David Sailor, Olyssa Starry

University Honors College Faculty Publication and Presentations

Study Region: This study took place in Portland Oregon, a city of over 600,000 residents located in the Willamette Valley in the state of Oregon in the Pacific Northwest region of the United States. Portland experiences a temperate climate with Mediterranean features. Study Focus: Runoff patterns from two extensive green roofs with substrate depths of 75 and 125 mm, situated on a 5000 square meter retail store, were compared over a one year period. Precipitation, irrigation, and storm water discharge were continuously monitored and the performance of the green roofs for storm water control was investigated in detail. New Hydrological …

Steady States And Transport Processes In Urban Ozone Balances, M. A. K. Khalil

Physics Faculty Publications and Presentations

Core chemical theory is combined with transport processes and local emissions to study the validity of commonly made assumptions regarding steady states to interpret urban and regional ozone data. It is shown that photo-stationary states of NO and NO2 cannot exist in urban areas or polluted regions in addition to the lack of such a state for ozone. Calculations in published papers, which make the assumption of a photo-stationary state for NO and NO2, or ozone, are likely to be inaccurate by unacceptable amounts. The Leighton Ratio is re-interpreted to show how it incorporates both the peroxy radical and transport …

Enhanced Terahertz Emission From Quantum Dot By Graphene-Coated Nanoparticle, Edin Sijercic, P. T. Leung

Physics Faculty Publications and Presentations

The terahertz (THz) emission from quantum dots in close proximity to graphene-coated nanoparticles is studied via phenomenological modeling with particular interest in the possibility of enhancement for such emission via the excitation of the graphene plasmons. It is shown that depending on various factors such as the damping factor and the Fermi level of the graphene, as well as the size and core material of the coated particle, such plasmonic-enhanced THz emission is indeed possible. This thus opens up a new pathway to provide intense THz sources for future applications.

Water Flow And Biofilm Cover Influence Environmental Dna Detection In Recirculating Streams, Arial Shogren, Jennifer L. Tank, Scott P. Egan, Olivia August, Emma J. Rosi, Brittany R. Hanrahan, Mark A. Renshaw, Crysta A. Gantz, Diogo Bolster

Environmental Science and Management Faculty Publications and Presentations

The increasing use of environmental DNA (eDNA) for determination of species presence in aquatic ecosystems is an invaluable technique for both ecology as a field and for the management of aquatic ecosystems. We examined the degradation dynamics of fish eDNA using an experimental array of recirculating streams, also using a “nested” primer assay to estimate degradation among eDNA fragment sizes. We introduced eDNA into streams with a range of water velocities (0.1–0.8 m s–1) and substrate biofilm coverage (0–100%) and monitored eDNA concentrations over time (∼10 d) to assess how biophysical conditions influence eDNA persistence. We found that the presence …

Reconsidering The Foundations Of Thermodynamics From An Engineering Perspective, Terry Bristol

Mathematics and Statistics Faculty Publications and Presentations

Currently, there are two approaches to the foundations of thermodynamics. One, associated with the mechanistical Clausius-Boltzmann tradition, is favored by the physics community. The other, associated with the post-mechanical Carnot tradition, is favored by the engineering community. The bold hypothesis is that the conceptual foundation of engineering thermodynamics is the more comprehensive. Therefore, contrary to the dominant consensus, engineering thermodynamics (ET) represents the true foundation of thermodynamics. The foundational issue is crucial to a number of unresolved current and historical issues in thermodynamic theory and practice. ET formally explains the limited successes of the ‘rational mechanical’ approaches as idealizing special …

Waste Stream And Green Purchasing Analysis At Bonneville Lock And Dam, Alexander Bienko

Environmental Science and Management Professional Master's Project Reports

The United States Army Corps of Engineers (USACE), Portland District, has jurisdiction on three locks and four dams in the Columbia River basin. These sites "contribute to a water resource management system that provides flood risk management, power generation, water quality improvement, fish and wildlife habitat and recreation on the Columbia River and some of its tributaries". The Bonneville Lock and Dam (Bonneville Project) site lies on the Columbia River approximately 40 miles east from Portland, Oregon. Portions of the site have been declared a National Historic Landmark, from its origins in President Franklin D. Roosevelt's New Deal program from …

Nadaka 2023 Management Plan, Andrea Hurzeler

Environmental Science and Management Professional Master's Project Reports

Nadaka 2023 is a management plan written for Nadaka Nature Park that aims to assess current conditions, define desired future conditions, and make recommendations to achieve those desired future conditions. Nadaka Nature Park is a publically owned nature area and park space located in the Wilkes East Neighborhood and bordering the Rockwood Neighborhood of Gresham, Oregon. Originally owned by the Camp Fire Organization, Nadaka was purchased in 1995 by the City of Gresham and opened to the public in 2001. Making up Nadaka is a 10 acre nature area and a 2 acre park space. The nature area consists of …

Triacetin Enhances Levels Of Acrolein, Formaldehyde Hemiacetals, And Acetaldehyde In Electronic Cigarette Aerosols, Shawna Vreeke, David H. Peyton, Robert Strongin

Chemistry Faculty Publications and Presentations

The health effects of inhaled electronic cigarette (ecigarette) flavoring compounds are largely unknown. Earlier reports of their chemical reactivity have been conflicting, with some claiming, for example, that the degradation of flavoring chemicals in e-cigarettes to aldehydes is statistically insignificant. It is thus important to understand how these molecules react to afford enhanced aerosol products. The purpose of the current study was to investigate the origin of formaldehyde, acrolein, and acetaldehyde in e-cigarettes that contain the popular additive, triacetin (TA). By using 13C labeling and a combination of 1H NMR and 13C NMR, we were able to identify that ester …

Using Transboundary Wildfire Exposure Assessments To Improve Fire Management Programs: A Case Study In Greece, Palaiologos Palaiologou, Alan A. Ager, Max Nielsen-Pincus, Cody Evers, Kostas Kalabokidis

Environmental Science and Management Faculty Publications and Presentations

Numerous catastrophic wildfires in Greece have demonstrated that relying on fire suppression as the primary risk-management strategy is inadequate and that existing wildfire-risk governance needs to be re-examined. In this research, we used simulation modelling to assess the spatial scale of wildfire exposure to communities and cultural monuments in Chalkidiki, Greece. The study area typifies many areas in Greece in terms of fire regimes, ownership patterns and fire-risk mitigation. Fire-transmission networks were built to quantify connectivity among land tenures and populated places. We found that agricultural and unmanaged wildlands are key land categories that transmit fire exposure to other land …

Preliminary Results Of Bayesian Networks And Reconstructability Analysis Applied To The Electric Grid, Marcus Harris, Martin Zwick

Systems Science Faculty Publications and Presentations

Reconstructability Analysis (RA) is an analytical approach developed in the systems community that combines graph theory and information theory. Graph theory provides the structure of relations (model of the data) between variables and information theory characterizes the strength and the nature of the relations. RA has three primary approaches to model data: variable based (VB) models without loops (acyclic graphs), VB models with loops (cyclic graphs) and state-based models (nearly always cyclic, individual states specifying model constraints). These models can either be directed or neutral. Directed models focus on a single response variable whereas neutral models focus on all relations …

Reconstructability & Dynamics Of Elementary Cellular Automata, Martin Zwick

Systems Science Faculty Publications and Presentations

Reconstructability analysis (RA) is a method to determine whether a multivariate relation, defined set- or information-theoretically, is decomposable with or without loss into lower ordinality relations. Set-theoretic RA (SRA) is used to characterize the mappings of elementary cellular automata. The decomposition possible for each mapping w/o loss is a better predictor than the λ parameter (Walker & Ashby, Langton) of chaos, & non-decomposable mappings tend to produce chaos. SRA yields not only the simplest lossless structure but also a vector of losses for all structures, indexed by parameter τ. These losses are analogous to transmissions in information-theoretic RA (IRA). IRA …

Introduction To Reconstructability Analysis, Martin Zwick

Systems Science Faculty Publications and Presentations

This talk will introduce Reconstructability Analysis (RA), a data modeling methodology deriving from the 1960s work of Ross Ashby and developed in the systems community in the 1980s and afterwards. RA, based on information theory and graph theory, is a member of the family of methods known as ‘graphical models,’ which also include Bayesian networks and log-linear techniques. It is designed for exploratory modeling, although it can also be used for confirmatory hypothesis testing. RA can discover high ordinality and nonlinear interactions that are not hypothesized in advance. Its conceptual framework illuminates the relationships between wholes and parts, a subject …

Reorganizing School Lunch For A More Just And Sustainable Food System In The Us, Jennifer Gaddis, Amy K. Coplen

Urban Studies and Planning Faculty Publications and Presentations

Public school lunch programs in the United States are contested political terrains shaped by government agencies, civil society activists, and agri-food companies. The particular organization of these programs has consequences for public health, social justice, and ecological sustainability. This contribution draws on political economy, critical food studies, and feminist economics to analyze the US National School Lunch Program, one of the world's oldest and largest government-sponsored school lunch programs. It makes visible the social and environmental costs of the "heat-and-serve" economy, where widely used metrics consider only the speed and volume of service as productive work. This study demonstrates that …

Beyond Spatial Autocorrelation: A Novel Approach Using Reconstructability Analysis, David Percy, Martin Zwick

Systems Science Faculty Publications and Presentations

Raster data are digital representations of spatial phenomena that are organized into rows and columns that typically have the same dimensions in each direction. They are used to represent image data at any scale. Common raster data are medical images, satellite data, and photos generated by modern smartphones.
Satellites capture reflectance data in specific bands of wavelength that correspond to red, green, blue, and often some infrared and thermal bands. These composite vectors can then be classified into actual land use categories such as forest or water using automated techniques. These classifications are verified on the ground using hand-held sensors. …

The Silencing Power Of Algorithms: How The Facebook News Feed Algorithm Manipulates Users' Perceptions Of Opinion Climates, Callie Jessica Morgan

University Honors Theses

This extended literature review investigates how the architecture and features of the Facebook Newsfeed algorithm, EdgeRank, can inhibit and facilitate the expression of political opinions. This paper will investigate how Elisabeth Noelle-Neumann's theory on public opinion, Spiral of Silence, can be used to assess the Facebook news feed as a political opinion source that actively shapes users' perceptions of minority and majority opinion climates. The feedback loops created by the algorithm's criteria influences users' decisions to self-censor or express their political opinions with interpersonal connections and unfamiliar connections on the site.

A Cyber-Physical System Framework For Early Detection Of Paroxysmal Diseases, Zuxing Gu, Yu Jiang, Min Zhou, Xiaoyu Song, Lui Sha

Computer Science Faculty Publications and Presentations

Paroxysmal diseases of inpatients are globally recognized as one of the top challenges in medicine. Poor clinical outcomes are primarily caused by delayed recognition, especially due to diverse clinical diagnostic criteria with complex manifestations, irregular episodes, and already overloaded clinical activities. With the proliferation of measuring devices and increased computational capabilities, cyber-physical characterization plays an increasingly important role in many domains to provide enabling technologies. This paper presents a cyber-physical system (CPS) framework to assist physicians in making earlier diagnoses of paroxysmal sympathetic hyperactivity based on existing medical knowledge. We propose a configurable diagnostic knowledge model to characterize clinical criteria …

Controls On Deuterium Excess Across Asia, John Bershaw

Geology Faculty Publications and Presentations

Deuterium excess (d-excess) is a second-order stable isotope parameter measured in meteoric water to understand both the source of precipitation and the evolution of moisture during transport. However, the interpretation of d-excess patterns in precipitation is often ambiguous, as changes in moisture source and processes during vapor transport both affect d-excess in non-unique ways. This is particularly true in Asia where continental moisture travels a long distance across diverse environments from unique moisture sources before falling as precipitation. Here, I analyzed published d-excess records from meteoric water throughout Asia to better characterize what influences d-excess values. I conclude that, (1) …

Contrasting Governance Learning Processes Of Climate-Leading And -Lagging Cities: Portland, Oregon, And Phoenix, Arizona, Usa, Jonathan H. Fink

Geology Faculty Publications and Presentations

The contrasting histories and political ecologies of two U.S. cities—Portland Oregon and Phoenix Arizona—shed light on their ability to learn from and influence the climate governance of their peers. Portland's populace, political leadership, and business sectors are motivated by environmental and social values, resulting in a collective sense of responsibility for fixing global problems like climate change. The city's pioneering land-use policies, green infrastructure, and multimodal transportation systems solidify its place at the climate action forefront. In contrast, libertarian Phoenix prioritizes real estate, efficient government, tourism, and protection of individual rights—the antithesis of Portland's altruism. However, because Phoenix's economic success …

Forest Collaborative Meeting Agenda, Gothenburg, Sweden, Environment For Development (Efd) Initiative

Forest Collaborative Research

Third Biannual Meeting of the Environment for Development (EfD) Forest Collaborative on June 25, 2018 at the School of Business, Economics and Law (SBEL) University of Gothenburg, Sweden.

Assessment Of Observational Uncertainty In Extreme Precipitation Over The Continental United States, Emily Anne Slinskey

Dissertations and Theses

An extreme precipitation categorization scheme, developed to temporally and spatially visualize and track the multi-scale variability of extreme precipitation climatology, is introduced over the continental United States and used as the basis for an observational dataset intercomparison. The categorization scheme groups three-day precipitation totals exceeding 100 mm into five precipitation categories, or "P-Cats". To assess observational uncertainty across a range of precipitation measurement approaches, we compare in situ station data from the Global Historical Climatology Network-Daily (GHCN-D), satellite derived data from the Tropical Rainfall Measuring Mission (TRMM), gridded station data from the Parameter-elevation Regression on Independent Slopes Model (PRISM), global …

Development Of A Direct Aqueous Synthetic Route For The Production Of Elemental Bismuth Nanoparticles, Colin Jon Hiatt

Dissertations and Theses

Bismuth nanoparticles (Bi NPs) for use as an X-ray contrast material have gained significant traction in recent years due to the high atomic number and generally accepted biological tolerance of bismuth. However, to be considered a viable candidate for use in this application, water solubility is a necessity, which poses a challenge, since bismuth tends to readily oxidize. For this reason, research into the direct aqueous synthesis of Bi NPs is still in its infancy and can be very difficult, as described in Chapter 1. The remaining chapters of the thesis describe the direct aqueous synthesis of Bi NPs starting …

An Exploration Of Linear Classifiers For Unsupervised Spiking Neural Networks With Event-Driven Data, Wesley Chavez

Dissertations and Theses

Object recognition in video has seen giant strides in accuracy improvements in the last few years, a testament to the computational capacity of deep convolutional neural networks. However, this computational capacity of software-based neural networks coincides with high power consumption compared to that of some spiking neural networks (SNNs), up to 300,000 times more energy per synaptic event in IBM's TrueNorth chip, for example. SNNs are also well-suited to exploit the precise timing of event-driven image sensors, which transmit asynchronous "events" only when the luminance of a pixel changes above or below a threshold value. The combination of event-based imagers …

Bounding Box Improvement With Reinforcement Learning, Andrew Lewis Cleland

Dissertations and Theses

In this thesis, I explore a reinforcement learning technique for improving bounding box localizations of objects in images. The model takes as input a bounding box already known to overlap an object and aims to improve the fit of the box through a series of transformations that shift the location of the box by translation, or change its size or aspect ratio. Over the course of these actions, the model adapts to new information extracted from the image. This active localization approach contrasts with existing bounding-box regression methods, which extract information from the image only once. I implement, train, and …

Dark Current Rts-Noise In Silicon Image Sensors, Benjamin William Hendrickson

Dissertations and Theses

Random Telegraph Signal (RTS) noise is a random noise source defined by discrete and metastable changes in the magnitude of a signal. Though observed in a variety of physical processes, RTS is of particular interest to image sensor fabrication where progress in the suppression of other noise sources has elevated its noise contribution to the point of approaching the limiting noise source in scientific applications.

There have been two basic physical sources of RTS noise reported in image sensors. The first involves a charge trap in the oxide layer of the source follower in a CMOS image sensor. The capture …