Physical Sciences and Mathematics Commons^™

Stakeholder Participation And Influence At State Public Utility Commissions, Genevieve Theresa Kruse

Dissertations and Theses

Despite the international consensus that climate change is a problem, few substantive policies are being pushed forward at the national level to meet international greenhouse gas reduction commitments under the Paris Agreement. The most significant climate change policies are emerging at state public utility commissions (PUCs). While PUCs were traditionally structured to regulate utilities, state PUCs are now finding themselves at the hub for renewable energy, clean energy, and distributed energy policies. Despite the increase in renewable and clean energy policies at state PUCs, there is a noticeably small environmental and clean energy stakeholder presence at those PUC proceedings. A …

Spatial And Temporal Variations Of Microplastic Concentrations In Portland's Freshwater Ecosystems, Rebecca Talbot, Elise F. Granek, Heejun Chang, Rosemary Wood, Susanne Brander

Geography Faculty Publications and Presentations

While microplastics are a pollutant of growing concern in various environmental compartments, less is known regarding the sources and delivery pathways of microplastics in urban rivers. We investigated the relationship between microplastic concentrations and various spatiotemporal factors (e.g., land use, arterial road length, water velocity, precipitation) in two watersheds along an urban-rural gradient in the Portland metropolitan area. Samples were collected in August, September, and February and were analyzed for total microplastic count and type. Nonparametric statistics were used to evaluate potential relationships with the explanatory variables, derived at both the subwatershed and near stream scales. In August, microplastic concentrations …

Environmental Decision Support Systems As A Service: Demonstration On Ce-Qual-W2 Model, Yoav Bornstein, Ben Dayan, Amir Cahn, Scott A. Wells

Civil and Environmental Engineering Faculty Publications and Presentations

An environmental decision support system (EDSS) can be used as an important tool for the rehabilitation and preservation of ecosystems. Nonetheless, high assimilation costs (both money and time) are one of the main reasons these tools are not widely adopted in practice. This work presents a low-cost paradigm of “EDSS as a Service.” This paradigm is demonstrated for developing a water quality EDSS as a service that utilizes the well-known CE-QUAL-W2 model as a kernel for deriving optimized decisions. The paradigm is leveraging new open-source technologies in software development (e.g., Docker, Kubernetes, and Helm) with cloud computing to significantly reduce …

The Trace Of T2 Takes No Repeated Values, Liubomir Chiriac, Andrei Jorza

Mathematics and Statistics Faculty Publications and Presentations

We prove that the trace of the Hecke operator T₂" role="presentation" style="box-sizing: border-box; margin: 0px; padding: 0px; display: inline-block; line-height: normal; font-size: 16.2px; word-spacing: normal; overflow-wrap: normal; white-space: nowrap; float: none; direction: ltr; max-width: none; max-height: none; min-width: 0px; min-height: 0px; border: 0px; position: relative;">T2 acting on the vector space of cusp forms of level one takes no repeated values, except for 0, which only occurs when the space is trivial.

Gps-Derived Interseismic Fault Locking Along The Jalisco–Colima Segment Of The Mexico Subduction Zone, Beatriz Cosenza-Muralles, Charles Demets, B. Márquez-Azúa, O. Sánchez, J. Stock, Enrique Cabral-Cano, Robert Mccaffrey

Geology Faculty Publications and Presentations

Northeastward subduction of the oceanic Rivera and Cocos plates in western Mexico poses a poorly understood seismic hazard to the overlying areas of the North America plate. We estimate the magnitude and distribution of interseismic locking along the northern ∼500 km of the Mexico subduction zone, with a series of elastic half-space inversions that optimize the fits to the velocities of 57 GPS stations in western Mexico. All velocities were corrected for the co-seismic, afterslip and viscoelastic rebound effects of the 1995 Colima–Jalisco and 2003 Tecomán earthquakes. We explore the robustness of interseismic locking estimates to a variety of mantle …

Extreme Winds Alter Influence Of Fuels And Topography On Megafire Burn Severity In Seasonal Temperate Rainforests Under Record Fuel Aridity, Cody Evers, Andres Holz, Sebastian Upton Busby, Max Nielsen-Pincus

Environmental Science and Management Faculty Publications and Presentations

Nearly 0.8 million hectares of land were burned in the North American Pacific Northwest (PNW) over two weeks under record-breaking fuel aridity and winds during the extraordinary 2020 fire season, representing a rare example of megafires in forests west of the Cascade Mountains. We quantified the relative influence of weather, vegetation, and topography on patterns of high burn severity (>75% tree mortality) among five synchronous megafires in the western Cascade Mountains. Despite the conventional wisdom in climate-limited fire regimes that regional drivers (e.g., extreme aridity, and synoptic winds) overwhelm local controls on vegetation mortality patterns (e.g., vegetation structure and …

Mass Capacity Analysis Of Stormwater Control Measures Using Synthetic Stormwater With Silica, Organic And Hydrocarbon Constituents, Craig Michael Fairbaugh

Dissertations and Theses

Stormwater control measure (SCM) performance is well studied regarding solids removal; however, analysis of mass loading capacity, long-term performance, and maintenance demands are challenging due to the variability and multiple constituents inherent in urban stormwater. This research examines the long-term water quality performance and sediment mass capacity of two common SCMs: high rate biofiltration (HRBF) and conventional bioretention (BRT). Pollutant removal trials were conducted in a laboratory setting per the New Jersey Department of Environmental Protection (NJDEP) filtration protocol in two phases: the first using inorganic sediment per the NJDEP protocol, the second phase with the addition of organic sediment …

Characterization Of High Mobility Channels For Use In Quantum Computing Devices, Payam Amin

Dissertations and Theses

Quantum computing promises computation that is fundamentally beyond the reach of classical computers. For the realization of a full-scale quantum computer, millions of quantum bits need to be fabricated on an integrated circuit and operated at cryogenic temperatures. Silicon and silicon-germanium based electron spin quantum bits have the advantage of leveraging decades of semiconductor industry knowledge for high volume manufacturability.

During the process development of any semiconductor device, material characterization is essential to understand and improve the process. Transmission electron microscopy is the only technique that could offer localized high spatial resolution characterization. In this work we have introduced two …

An Aggregation-Based Nonlinear Multigrid Solver For Two-Phase Flow And Transport In Porous Media, Chak Shing Lee, Francois Hamon, Nicola Castelletto, Panayot S. Vassilevski, Joshua A. White

Mathematics and Statistics Faculty Publications and Presentations

A nonlinear multigrid solver for two-phase flow and transport in a mixed fractional-flow velocity-pressure-saturation formulation is proposed. The solver, which is under the framework of the full approximation scheme (FAS), extends our previous work on nonlinear multigrid for heterogeneous diffusion problems. The coarse spaces in the multigrid hierarchy are constructed by first aggregating degrees of freedom, and then solving some local flow problems. The mixed formulation and the choice of coarse spaces allow us to assemble the coarse problems without visiting finer levels during the solving phase, which is crucial for the scalability of multigrid methods. Specifically, a …

Dependence Comparisons Of Order Statistics In The Proportional Hazards Model, Subhash C. Kochar

Mathematics and Statistics Faculty Publications and Presentations

Let X₁,…,X_n be mutually independent exponential random variables with distinct hazard rates λ₁,…,λ_n > 0 and let Y₁,…,Y_n be a random sample from the exponential distribution with hazard rate $\bar \lmd = \sum_{i=1}^n \lmd_i/n$. Also let X_1:n < ⋯ < X_n:n and Y_1:n < ⋯ < Y_n:n be their associated order statistics. It is shown that for 1 ≤ i < j ≤ n, the generalized spacing X_j:n - X _i:n is more dispersed than Y_j:n− Y_i:n according to dispersive ordering. This result is used to solve a long standing open problem …

Effects Of Pore-Forming Peptides (Melittin And Magainin 2) On The Phospholipid Bilayer Interior, Elmukhtar Ehmed Alhatmi

Dissertations and Theses

Antimicrobial peptides (AMPs) are one of the most promising solutions to drug-resistant bacteria. Melittin and magainin 2 are two of the most representative and extensively studied AMPs. In this research, I investigated the interaction of these two AMPs with three models of cell membranes: 80% POPC 20% POPG, 40%POPC 40% POPE and 20% POPG, and 80%POPC 20%POPG plus 30% mole fraction of cholesterol. Time-resolved fluorescence emission and fluorescence anisotropy decays of the fluorescent probe 1,6-diphenyl-1,3,5-hexatriene (DPH) were analyzed to determine the effects of AMPs on the bilayer headgroup packing and changes in the interior of the phospholipid bilayer during the …

Fenchel-Rockafellar Theorem In Infinite Dimensions Via Generalized Relative Interiors, Dang Van Cuong, Mau Nam Nguyen, B. S. Mordukhovich, G. Sandine

Mathematics and Statistics Faculty Publications and Presentations

In this paper we provide further studies of the Fenchel duality theory in the general framework of locally convex topological vector (LCTV) spaces. We prove the validity of the Fenchel strong duality under some qualification conditions via generalized relative interiors imposed on the epigraphs and the domains of the functions involved. Our results directly generalize the classical Fenchel-Rockafellar theorem on strong duality from finite dimensions to LCTV spaces.

Using Intrinsically-Typed Definitional Interpreters To Verify Compiler Optimizations In A Monadic Intermediate Language, Dani Barrack

Dissertations and Theses

Compiler optimizations are critical to the efficiency of modern functional programs. At the same time, optimizations that unintentionally change the semantics of programs can systematically introduce errors into programs that pass through them. The question of how to best verify that optimizations and other program transformations preserve semantics is an important one, given the potential for error introduction. Dependent types allow us to prove that properties about our programs are correct, as well as to design data types and interpreters in such a way that they are correct-by-construction. In this thesis, we explore the use of dependent types and intrinsically-typed …

Coming To Know The Local Environment: Children's Experiences In Rautamai Gaunpalika, Nepal, Elsie Nicole Love

Dissertations and Theses

This qualitative research, conducted over three months from late monsoon season into early fall of 2018 with twenty-six children and thirteen adults, explores how children in the hills of Rautamai Gaunpalika, Province 1, Nepal come to know their local environment. Semi-structured interviews with children, their family members, and teachers, and participant observation with children as they worked and played in forests, fields, and streams, suggest that outside of school, children come to know their local environment in the following ways: through participation in and application of knowledge to subsistence practices; through collaborative learning and teaching in mixed-age groups; through relationships …

Cetacean Strandings In The Us Pacific Northwest 2000–2019 Reveal Potential Linkages To Oceanographic Variability, Amanda J. Warlick, Jessica L. Huggins, Dyanna M. Lambourn, Deborah A. Duffield, Dalin Nichole D'Alessandro, James M. Rice, John Calambokidis, M. Bradley Hanson, Joseph K. Gaydos, Multiple Additional Authors

Biology Faculty Publications and Presentations

Studying patterns in marine mammal stranding cases can provide insight into changes in population health, abundance, and distribution. Cetaceans along the United States West coast strand for a wide variety of reasons, including disease, injury, and poor nutritional status, all of which may be caused by both natural and anthropogenic factors. Examining the potential drivers of these stranding cases can reveal how populations respond to changes in their habitat, notably oceanographic variability and anthropogenic activities. In this study, we aim to synthesize recent patterns in 1,819 cetacean strandings across 26 species in the Pacific Northwest from 2000 to 2019 to …

An Introduction To Number Theory, J. J. P. Veerman

PDXOpen: Open Educational Resources

These notes are intended for a graduate course in Number Theory. No prior familiarity with number theory is assumed.

Chapters 1-14 represent almost 3 trimesters of the course. Eventually we intend to publish a full year (3 trimesters) course on number theory. The current content represents courses the author taught in the academic years 2020-2021 and 2021-2022.

It is a work in progress. If you have questions or comments, please contact Peter Veerman (veerman@pdx.edu).

Continuum Dynamics And Statistical Correction Of Compositional Heterogeneity In Multivalent Idp Oligomers Resolved By Single-Particle Em, Barmak Mostofian, Russell Mcfarland, Aiden Estelle, Jesse Howe, Elisar J. Barbar, Steve L. Reichow, Daniel M. Zuckerman

Chemistry Faculty Publications and Presentations

Multivalent intrinsically disordered protein (IDP) complexes are prevalent in biology and act in regulation of diverse processes, including transcription, signaling events, and the assembly and disassembly of complex macromolecular architectures. These systems pose significant challenges to structural investigation, due to continuum dynamics imparted by the IDP and compositional heterogeneity resulting from characteristic low-affinity interactions. Here, we developed a modular pipeline for automated single-particle electron microscopy (EM) distribution analysis of common but relatively understudied semi-ordered systems: 'beads-on-a-string' assemblies, composed of IDPs bound at multivalent sites to the ubiquitous ∼20kDacross-linking hub protein LC8. This approach quantifies conformational geometries and compositional heterogeneity on …

Co-Seismic And Post-Seismic Deformation For The 1995 Colima–Jalisco And 2003 Tecoman Thrust Earthquakes, Mexico Subduction Zone, ́ From Modelling Of Gps Data, Beatriz Cosenza-Muralles, Charles Demets, O. Sanchez, Enrique Cabral-Cano, J. Stock, B. Márquez-Azúa, Robert Mccaffrey

Geology Faculty Publications and Presentations

We invert ∼25 yr of campaign and continuous Global Positioning System daily positions at 62 sites in southwestern Mexico to estimate co-seismic and post-seismic afterslip solutions for the 1995 M_w = 8.0 Colima–Jalisco and the 2003 M_w = 7.5 Tecomán earthquakes, and the long-term velocity of each GPS site. Estimates of the viscoelastic effects of both earthquakes from a 3-D model with an elastic crust and subducting slab, and linear Maxwell viscoelastic mantle are used to correct the GPS position time-series prior to our time-dependent inversions. The preferred model, which optimizes the fit to data from several years …

An Algorithm For Identifying Eigenvectors Exhibiting Strong Spatial Localization, Jeffrey S. Ovall, Robyn Reid

Mathematics and Statistics Faculty Publications and Presentations

We introduce an approach for exploring eigenvector localization phenomena for a class of (unbounded) selfadjoint operators. More specifically, given a target region and a tolerance, the algorithm identifies candidate eigenpairs for which the eigenvector is expected to be localized in the target region to within that tolerance. Theoretical results, together with detailed numerical illustrations of them, are provided that support our algorithm. A partial realization of the algorithm is described and tested, providing a proof of concept for the approach.

Does Restoration Of Urban Riparian Zones Impact Stream Water Quality In Portland, Oregon, Ash Ivanov

University Honors Theses

Riparian zones influence urban stream quality through factors such as shading the stream, adding nutrients through leaf litter, stabilizing the stream banks to reduce turbidity, and filtering toxins out of the water. Riparian restoration often involves changing plant assemblage to be more diverse and include primarily native species instead of non-native, improving connection to the stream through changing stream morphology, improving species habitat, and reducing pollution. The goal of this study was to determine if urban riparian restoration projects in the region were successful, and if not, why that may be the case. The study was performed in the Portland, …

Classifying Dead Code In Software Development, Arman Alavizadeh

University Honors Theses

Dead code pervades as an issue in the world of software development as a source of many famous software disasters such as the ARIANE 5 rocket failure and chemical bank withdrawal error. Defining dead code on narrow levels of granularity has not been fully explored, yet is crucial to better our understanding of dead code. Here we will be starting a discussion on how to approach classifying dead code via comparing dead code research specific to an industry segment. Research will be compared primarily by methodology and limitations. Dead code subtype classifications are gleaned from research comparisons and can serve …

Minimality Of Integer Bar Visibility Graphs, Emily Dehoff

University Honors Theses

A visibility representation is an association between the set of vertices in a graph and a set of objects in the plane such that two objects have an unobstructed, positive-width line of sight between them if and only if their two associated vertices are adjacent. In this paper, we focus on integer bar visibility graphs (IBVGs), which use horizontal line segments with integer endpoints to represent the vertices of a given graph. We present results on the exact widths of IBVGs of paths, cycles, and stars, and lower bounds on trees and general graphs. In our main results, we find …

Efficient Capture Of Co2 And Its Selective Reduction To Formic Acid Using Tin-Based Nanomaterials, Emmanuel Oluwaseun Abdul

Dissertations and Theses

CO₂ emissions from the combustion of fossil fuels and other anthropogenic sources have become the main contributing factors to global warming. Chemical methods of absorbing/capturing CO₂ from combustion flue gases have made it a sought-after approach in engineering emission solutions because of its simplistic and convenient operation and high absorption efficiency. The conversion of CO₂ into renewable fuels and high energy density chemicals by clean and economic processes has drawn scientists' attention over the decades. The electrocatalytic conversion of CO₂ using Sn-based materials has been demonstrated to be a promising method for producing formate, an important …

Stratigraphic And Geochemical Evaluation Of Distal Flows Of The Columbia River Flood Basalts In The Greater Vale Area, Southeastern Oregon, Lena Marie Fox

Dissertations and Theses

Exposures of Columbia River Basalt Group (CRBG) in southeastern Oregon are dominated by the four main phase CRBG units: Steens Basalt, Imnaha Basalt, Grande Ronde Basalt (GRB), and Picture Gorge Basalt (PGB). These units are best seen in stratigraphic sequence along the Malheur Gorge corridor of southeastern Oregon, between the towns of Vale and Juntura, with flows of Steens Basalt from the south overlain by flows of Imnaha and GRB from the north. Recently, PGB flows were found to be part of the eastern Malheur Gorge stratigraphy as well.

In Malheur Gorge, local units of Birch and Hunter Creek Basalt …

Visualizing Connectivity For Wildlife In A World Without Roads, Catherine De Rivera, Leslie Bliss-Ketchum, Martin Lafrenz, A. V. Hanson, L. E. Mckinney-Wise, A. H. Rodriguez, J. Schultz, Alana Simmons, D. Taylor Rodriguez, Multiple Additional Authors

Environmental Science and Management Faculty Publications and Presentations

Roads are not the only determining factor for wildlife movement across the landscape, but due to the extensive distribution of the road network their impact can be dramatic. Although it has been well documented that roads decrease habitat connectivity for wildlife due to animal-vehicle collisions, habitat fragmentation, and avoidance behavior, approaches for identifying connectivity across the landscape often do not fully examine the barrier effect of roads. Here, we explored the extent of the impact of roadways on wildlife connectivity by using Omniscape to model connectivity including and without the barrier effect of roads, then evaluating the difference between these …

Maximum Entropy And Constraints In Composite Systems, John D. Ramshaw

Physics Faculty Publications and Presentations

The principle of maximum entropy (PME), as expounded by Jaynes, is based on the maximization of the Boltzmann-Gibbs-Shannon (BGS) entropy subject to linear constraints. The resulting probability distributions are of canonical (exponential) form. However, the rationale for linear constraints is nebulous, and probability distributions are not always canonical. Here we show that the correct noncanonical distribution for a system in equilibrium with a finite heat bath is implied by the unconstrained maximization of the total BGS entropy of the system and bath together. This procedure is shown to be equivalent to maximizing the BGS entropy of the system alone subject …

Variability Of Potential Soil Nitrogen Cycling Rates In Stormwater Bioretention Facilities, Erin N. Rivers, Jennifer L. Morse

Environmental Science and Management Faculty Publications and Presentations

Low-impact development (LID) is a common management practice used to infiltrate and filter stormwater through vegetated soil systems. The pollutant reduction potential of these systems is often characterized by a single pollutant removal rate; however, the biophysical properties of soils that regulate the removal of pollutants can be highly variable depending on environmental conditions. The goal of this study was to characterize the variability of soil properties and nitrogen (N) cycling rates in bioretention facilities (BRFs). Soil properties and potential N cycling processes were measured in nine curbside bioretention facilities (BRFs) in Portland, OR during summer and winter seasons, and …

Speciation Of Diaryliodonium Salts In Solution And Their Reactivity Towards N-Nucleophiles (Phthalimide And Amines) And O-Nucleophiles (Phenols And Phenoxide), Souradeep Basu

Dissertations and Theses

Benzenoid rings are prevalent in pharmaceutical drug molecules, agrochemical molecules and even in some polymers used in electronic device. Aryl rings are often installed using metal catalysis, however, metal free arylations are known but limited. Diaryliodonium salts are novel electrophilic arylating agents. Herein, metal free N-arylation of phthalimide and diarylether formation using aryl(TMP)iodonium salts is described.

The structure of diaryliodonium salts has been primarily studied in either the solid state or in-silico. The structure and speciation of diaryliodonium salts in solution is not well explored. In this work evidence of dimer formation of aryl(Mes)iodonium salts in chloroform using …

The Castle Rock And Ironside Mountain Calderas, Eastern Oregon, Usa: Adjacent Venting Sites Of Two Dinner Creek Tuff Units—The Most Widespread Tuffs Associated With Columbia River Flood Basalt Volcanism, Matthew Cruz, Martin J. Streck

Geology Faculty Publications and Presentations

The Dinner Creek Tuff is an important unit of mid-Miocene rhyolite volcanism contemporaneous to flood basalts of the Columbia River magmatic province. Field mapping along with analytical data of tuff samples identify two calderas, the Castle Rock and Ironside Mountain calderas, as the venting sites of two widespread ignimbrites of the Dinner Creek Tuff. Both calderas lie within the area of the proposed general storage sites of main-phase Columbia River Basalt magmas. The Castle Rock caldera formed during the eruption of the 16.16 Ma Dinner Creek Tuff unit 1. The northwestern boundary of the caldera is roughly defined by the …

Development And Evaluation Of A Survey To Measure Student Engagement At The Activity Level In General Chemistry, Nicole Naibert, Jack Barbera

Chemistry Faculty Publications and Presentations

Student engagement is an important consideration when incorporating active learning activities into a classroom. To facilitate the large-scale assessment of students’ engagement in activities, a survey measure must first be developed and evaluated. Therefore, the goal of this study was to create a self-report measure of student engagement for use with active learning activities in general chemistry classes. The Activity Engagement Survey (AcES) was modified from an existing survey of engagement of middle and high school science students that contained behavioral, cognitive, emotional, and social engagement items. Multiple rounds of response process interviews and factor analyses were used to modify …