Digital Commons Network^™

Factors Driving The Concentration Of Ephemeral Flow, Gretchen Anne Guyer

Dissertations and Theses

In spite of decades of related research, stream channel initiation is still not well understood. Current theories of channel initiation are grounded in research conducted by Montgomery and Dietrich, largely in the transport limited, temperate, humid climate of the Pacific Northwest, USA. This field data driven work concluded that the drainage area required for channel initiation is directly correlated to the slope of the contributing area. However, there are a host of related variables that have yet to be examined in the field. This study revisits the slope-area relationship focusing on ephemeral overland flow in headwaters of both the Pacific …

Origin And Use Of Pedagogical Content Knowledge: A Case Study Of Three Math Teachers And Their Students, Christopher Neal Wood

Dissertations and Theses

Teachers must have specific knowledge of a subject and how to teach it to promote learning in their students (also known as pedagogical content knowledge). Research has shown that project-based curriculum can be an effective way for teachers to leverage this knowledge into deeper student understanding and application readiness, but observations about when and how this happens in the classroom have not been adequately documented. In this study we will explore teaching and learning in a middle-school boat-building curriculum focused on real-world application of math concepts. The boat-building program took place over one week, included seven students, and was taught …

Relationships That Extend Beyond The Fence-Line: Private Landowner Attitudes And Interest In Conservation Easements, Ashley Lyn Vizek

Dissertations and Theses

Private land conservation provides an opportunity to address problems of habitat fragmentation and biodiversity loss caused by an increase in the development and parcelization of private land. Conservation easements (CEs) are an innovative tool used by land trusts to protect significant natural qualities of private land in perpetuity, while also allowing the land to remain in private ownership. Traditionally, property represents an individualistic relationship, however, CEs redefine this relationship by seeking to maximize the overlap in private and public goods in property. In this study, I explore the relationship between the common good and private property through an analysis of …

Event Detection Using Correlation Within Arrays Of Streaming Pmu Data, Jordan Landford

Dissertations and Theses

This thesis provides a synchrophasor data analysis methodology that leverages both statistical correlation techniques and a statistical distribution in order to identify data inconsistencies, as well as power system contingencies. This research utilizes archived Phasor Measurement Unit (PMU) data obtained from the Bonneville Power Administration in order to show that this methodology is not only feasible, but extremely useful for power systems monitoring, decision support, and planning purposes.

By analyzing positive sequence voltage angles between a pair of PMUs at two different substation locations, an historic record of correlation is established. From this record, a Rayleigh distribution of correlation coefficients …

The Intermediate Value Theorem As A Starting Point For Inquiry-Oriented Advanced Calculus, Stephen Raymond Strand Ii

Dissertations and Theses

Making the transition from calculus to advanced calculus/real analysis can be challenging for undergraduate students. Part of this challenge lies in the shift in the focus of student activity, from a focus on algorithms and computational techniques to activities focused around definitions, theorems, and proofs. The goal of Realistic Mathematics Education (RME) is to support students in making this transition by building on and formalizing their informal knowledge. There are a growing number of projects in this vein at the undergraduate level, in the areas of abstract algebra (TAAFU: Larsen, 2013; Larsen & Lockwood, 2013), differential equations (IO-DE: Rasmussen & …

The Effects Of Phosphonic Acids In Dye-Sensitized Solar Cells, Keith Edward James

Dissertations and Theses

Novel methods for the construction of dye-sensitized solar cells (DSSCs) were developed. A thin dense underlayer of TiO₂ was applied on fluorine-doped tin oxide (FTO) glass using as a precursor Tyzor AA-105. Subsequently a mesoporous film of P-25 TiO₂ was applied by spreading a suspension uniformly over the surface of the underlayer and allowing the plate to slowly dry while resting on a level surface. After sintering at 500° C slides were treated with TCPP as a sensitizing dye and assembled into DSSCs. A novel method was used to seal the cells; strips of Parafilm® were used as …

Green Roofs And Urban Biodiversity: Their Role As Invertebrate Habitat And The Effect Of Design On Beetle Community, Sydney Marie Gonsalves

Dissertations and Theses

With over half the world's population now living in cities, urban areas represent one of earth's few ecosystems that are increasing in extent, and are sites of altered biogeochemical cycles, habitat fragmentation, and changes in biodiversity. However, urban green spaces, including green roofs, can also provide important pools of biodiversity and contribute to regional gamma diversity, while novel species assemblages can enhance some ecosystem services. Green roofs may also mitigate species loss in urban areas and have been shown to support a surprising diversity of invertebrates, including rare and endangered species. In the first part of this study I reviewed …

Developing A Hierarchical Decision Model To Evaluate Nuclear Power Plant Alternative Siting Technologies, Marwan Mossa Lingga

Dissertations and Theses

A strong trend of returning to nuclear power is evident in different places in the world. Forty-five countries are planning to add nuclear power to their grids and more than 66 nuclear power plants are under construction.

Nuclear power plants that generate electricity and steam need to improve safety to become more acceptable to governments and the public. One novel practical solution to increase nuclear power plants' safety factor is to build them away from urban areas, such as offshore or underground. To date, Land-Based siting is the dominant option for siting all commercial operational nuclear power plants. However, the …

An Investigation Of Invasion: Boater Knowledge Concerning Aquatic Invasive Species And The Influence Of The New Zealand Mud Snail On Benthic Food Webs, Samuel Anthony Cimino

Dissertations and Theses

Invasive species are second only to habitat loss as a leading cause of native species displacement and the management of invasive species costs hundreds of billions annually. Invasion is often conceptualized as a series of stages (Transport, Introduction, Establishment, and Spread), which encourages ecologists to isolate factors that might enable a species to pass from one stage to another and therefore guide prevention or impact management. This thesis addresses each stage of invasion and attempts to determine where management might succeed in preventing invasion or minimizing impacts. The transport and introduction of aquatic invasive species (AIS) was analyzed by conducting …

Accuracy Of Wave Speeds Computed From The Dpg And Hdg Methods For Electromagnetic And Acoustic Waves, Nicole Michelle Olivares

Dissertations and Theses

We study two finite element methods for solving time-harmonic electromagnetic and acoustic problems: the discontinuous Petrov-Galerkin (DPG) method and the hybrid discontinuous Galerkin (HDG) method.

The DPG method for the Helmholtz equation is studied using a test space normed by a modified graph norm. The modification scales one of the terms in the graph norm by an arbitrary positive scaling parameter. We find that, as the parameter approaches zero, better results are obtained, under some circumstances. A dispersion analysis on the multiple interacting stencils that form the DPG method shows that the discrete wavenumbers of the method are complex, explaining …

Physics-Based Imaging Methods For Terahertz Nondestructive Evaluation Applications, Gabriel Paul Kniffin

Dissertations and Theses

Lying between the microwave and far infrared (IR) regions, the "terahertz gap" is a relatively unexplored frequency band in the electromagnetic spectrum that exhibits a unique combination of properties from its neighbors. Like in IR, many materials have characteristic absorption spectra in the terahertz (THz) band, facilitating the spectroscopic "fingerprinting" of compounds such as drugs and explosives. In addition, non-polar dielectric materials such as clothing, paper, and plastic are transparent to THz, just as they are to microwaves and millimeter waves. These factors, combined with sub-millimeter wavelengths and non-ionizing energy levels, makes sensing in the THz band uniquely suited for …

Evaluating An Assessment Instrument For The Oregon Environmental Literacy Plan, Susan Mae Duncan

Dissertations and Theses

This mixed methods study evaluated the validity, and reliability of an instrument designed to assess a middle school student's proficiency in systems thinking as described in the 2010 Oregon Environmental Literacy Plan. In Stage 1, a forum of middle school students, formal, and non-formal educators used the Delphi technique to reach consensus regarding which skills were important to include in a scoring guide for systems thinking. In Stage 2, the scoring guide was field tested by formal and non-formal educators using a sample of students' work. The two groups' scores were compared using Cohen's kappa to make inferences regarding inter-rater …

Interview With Judith Ramaley, Judith A. Ramaley, Clarence Hein

Portland State University Oral Histories

Dr. Ramaley discusses her career and accomplishments as President of Portland State University (PSU) from 1990-1997, with emphasis on the development of PSU's general education program, productive collaboration between students, faculty, and the urban community, and growing Portland State as Oregon's urban university.

A transcript of this interview is available for download.

Tidal River Dynamics: Implications For Deltas, Ton Hoitink, David A. Jay

Civil and Environmental Engineering Faculty Publications and Presentations

Tidal rivers are a vital and little studied nexus between physical oceanography and hydrology. It is only in the last few decades that substantial research efforts have been focused on the interactions of river discharge with tidal waves and storm surges into regions beyond the limit of salinity intrusion, a realm that can extend inland hundreds of kilometers. One key phenomenon resulting from this interaction is the emergence of large fortnightly tides, which are forced long waves with amplitudes that may increase beyond the point where astronomical tides have become extinct. These can be larger than the linear tide itself …

Investigations Of An "Objectness" Measure For Object Localization, Lewis Richard James Coates

Dissertations and Theses

Object localization is the task of locating objects in an image, typically by finding bounding boxes that isolate those objects. Identifying objects in images that have not had regions of interest labeled by humans often requires object localization to be performed first. The sliding window method is a common naïve approach, wherein the image is covered with bounding boxes of different sizes that form windows in the image. An object classifier is then run on each of these windows to determine if each given window contains a given object. However, because object classification algorithms tend to be computationally expensive, it …

On The Variability Of Pacific Ocean Tides At Seasonal To Decadal Time Scales: Observed Vs Modelled, Adam Thomas Devlin

Dissertations and Theses

Ocean tides worldwide have exhibited secular changes in the past century, simultaneous with a global secular rise in mean sea level (MSL). The combination of these two factors contributes to higher water levels, and may increase threats to coastal regions and populations over the next century. Equally as important as these long-term changes are the short-term fluctuations in sea levels and tidal properties. These fluctuations may interact to yield locally extreme water level events, especially when combined with storm surge. This study, presented in three parts, examines the relationships between tidal anomalies and MSL anomalies on yearly and monthly timescales, …

Tree Graphs And Orthogonal Spanning Tree Decompositions, James Raymond Mahoney

Dissertations and Theses

Given a graph G, we construct T(G), called the tree graph of G. The vertices of T(G) are the spanning trees of G, with edges between vertices when their respective spanning trees differ only by a single edge. In this paper we detail many new results concerning tree graphs, involving topics such as clique decomposition, planarity, and automorphism groups. We also investigate and present a number of new results on orthogonal tree decompositions of complete graphs.

Introducing Complex Systems Analysis In High School Mathematics Using System Dynamics Modeling: A Potential Game-Changer For Mathematics Instruction, Diana Marie Fisher

Dissertations and Theses

Complex systems abound on this planet, in the composition of the human body, in ecosystems, in social interaction, in political decision-making, and more. Analytical methods allowing us to better understand how these systems operate and, consequently, to have a chance to intervene and change the undesirable behavior of some of the more pernicious systems have developed and continue to be enhanced via quickly changing technology. Some of these analytical methods are accessible by pre-college students, but have not been widely used at that level of education. Jay Forrester, the founder of one of the methodologies, System Dynamics (SD), used to …

Accommodation Space In A High-Wave-Energy Inner-Shelf During The Holocene Marine Transgression: Correlation Of Onshore And Offshore Inner-Shelf Deposits (0–12 Ka) In The Columbia River Littoral Cell System, Washington And Oregon, Usa, Curt D. Peterson, Dave C. Twichell, Michael C. Roberts, Sandy Vanderburgh, Steve W. Hostetler

Geology Faculty Publications and Presentations

The Columbia River Littoral Cell (CRLC), a high-wave-energy littoral system, extends 160 km alongshore, generally north of the large Columbia River, and 10–15 km in across-shelf distance from paleo-beach backshores to about 50 m present water depths. Onshore drill holes (19 in number and 5–35 m in subsurface depth) and offshore vibracores (33 in number and 1–5 m in subsurface depth) constrain inner-shelf sand grain sizes (sample means 0.13–0.25 mm) and heavy mineral source indicators (> 90% Holocene Columbia River sand) of the inner-shelf facies (≥ 90% fine sand). Stratigraphic correlation of the transgressive ravinement surface in onshore drill holes …

The Foundations Of Network Dynamics In An Rna Recombinase System, Jessica Anne Mellor Yeates

Dissertations and Theses

How life originated from physical and chemical processes is one of the great questions still unanswered today. Studies towards this effort have transitioned from the notion of a single self-replicating entity to the idea that a network of interacting molecules made this initial biological leap. In order to understand the chemical kinetic and thermodynamic mechanisms that could engender pre-life type networks we present an empirical characterization of a network of RNA recombinase molecules. We begin with 1-, 2-, and 3-molecular ensembles and provide a game theoretic analysis to describe the frequency dependent dynamics of competing and cooperating RNA genotypes. This …

Discrete Stability Of Dpg Methods, Ammar Harb

Dissertations and Theses

This dissertation presents a duality theorem of the Aubin-Nitsche type for discontinuous Petrov Galerkin (DPG) methods. This explains the numerically observed higher convergence rates in weaker norms. Considering the specific example of the mild-weak (or primal) DPG method for the Laplace equation, two further results are obtained. First, for triangular meshes, the DPG method continues to be solvable even when the test space degree is reduced, provided it is odd. Second, a non-conforming method of analysis is developed to explain the numerically observed convergence rates for a test space of reduced degree. Finally, for rectangular meshes, the test space is …

Thiophene Based Molecular Sensors Towards Mercury Detection, Austin K. Shigemoto, Carolyn N. Virca, Sam Underwood, Lauren Shetterly, Theresa M. Mccormick

Student Research Symposium

Toxic heavy metals such as mercury have increased in concentration in the environment due to pollution. Inorganic mercury in the environment can be later converted to a more toxic form: methylmercury. Regular consumption of fish containing methylmercury can lead to several cognitive and motor disorders as well as Minamata disease. The current methods used to detect both methylmercury and inorganic mercury in sea life and drinking water involve long sample preparation and cost. In order to more efficiently track this toxic metal in the environment and identify contaminated food and water sources, a cheaper and faster method of detection is …

Math And Sudoku: Exploring Sudoku Boards Through Graph Theory, Group Theory, And Combinatorics, Kyle Oddson

Student Research Symposium

Encoding Sudoku puzzles as partially colored graphs, we state and prove Akman’s theorem [1] regarding the associated partial chromatic polynomial [5]; we count the 4x4 sudoku boards, in total and fundamentally distinct; we count the diagonally distinct 4x4 sudoku boards; and we classify and enumerate the different structure types of 4x4 boards.

Listening To Lasers: Photoacoustic Gas Sensing, Michael Hopkins

Student Research Symposium

Herein lies the makings of a sensor for gaseous materials due to the technique known as photo-acoustic spectroscopy. Whereby a gas filled metallic tube of known resonance has an impingement to its open aspect a beam of photons of known colour and at a specified rate such that the rate of incoming light corpuscles matches the natural standing wave frequency for the column of gas within said tube, to wit resonance. Through foresight of the molecular orbital theory and historic datums on the subject of infrared spectroscopy one naturally comes to the employment of absorbance transfiguring energy to kinetic motions …

Aquifer Vulnerability Modeling In New Jersey Through The Use Of Modified Drastic Methodology, Clement Uduk, Tanja Hopmans

Student Research Symposium

Due to the global average increase in temperature over the last 50 years, sea levels have been rising and making coastal aquifers more susceptible to saltwater intrusion. The average rate of sea level rise has increased from 2 mm/year to 3.5 mm/year during the twentieth century. The state of New Jersey is not only densely populated but the development along coastlines makes inundation a potential serious threat. New Jersey is diverse in aquifer types, in addition to the types of water bodies surrounding New Jersey, and makes for an interesting case study for groundwater vulnerability. The EPA has a universal …

The Dc Algorithm & The Constrained Fermat-Torricelli Problem, Nathan Peron Lawrence, George Blikas

Student Research Symposium

The theory of functions expressible as the Difference of Convex (DC) functions has led to the development of a rich field in applied mathematics known as DC Programming.We survey the work of Pham Dinh Tao and Le Thi Hoai An in order to understand the DC Algorithm (DCA) and its use in solving clustering problems. Further, we present several other methods that generalize the DCA for any norm. These powerful tools enable researchers to reformulate objective functions, not necessarily convex, into DC Programs.

The Fermat-Torricelli problem is visited in light of convex analysis and various norms. Pierre de Fermat proposed …

Then And Now: Vegetative Change Detection On Mount St. Helens 2000-2015, Douglas S. Thalacker, Andrés Holz

Student Research Symposium

The 1980 eruption of Mount St. Helens (MSH) proved a dramatic event with many important socio-economic consequences. In addition, this eruption resulted in an array of ecological consequences with subsequent studies and profound theoretical ramifications. The eruption created a complex gradient in disturbance severity on the northern aspect of MSH3, promoting successional processes from varying starting points and change rates. This study uses a landscape-scale approach to quantify spatio-temporal trends in vegetative responses to the eruption from 2000-2015, relying on Landsat TM and ETM+ imagery focusing on the primary and (i.e. no biological legacies) secondary (i.e. with biological legacies) succession …

How Calculus Students At Successful Programs Talk About Their Instructors, Annie Bergman, Dana Kirin, Ben Wallek

Student Research Symposium

Over the past decade, numerous reports point to the need for national efforts to increase the number of students pursuing and professionals with degrees in science, technology, engineering, and mathematics (STEM) fields (see for example NSB, 2007; PCAST, 2012; Thomasian, 2011). According to the PCAST report (2012) increasing the retention rate of the students who enter college intending to major in a STEM field has the potential to significantly decrease the gap between the number of STEM degrees produced and the projected number of STEM degrees needed to sustain the United States position in the global market. While there are …

Analytic Thinking Predicts Vaccine Endorsement: Cognitive Style As An Antecedent Of Vaccine Attitudes, Daniel A. Anderson

Student Research Symposium

Relationships between cognitive style (CS) and affective orientation toward childhood vaccines (AO) were tested in a sample of US adults, controlling for known covariates. Findings suggest an analytic cognitive style predicts greater likelihood of endorsing childhood vaccination (higher AO). Results highlight relationships between individual cognition and cultural influences upon vaccine-beliefs.

How 5-Day Weather Patterns And Buoyancy Regulation Impact Algal Community Assemblage, Roberta Brunkalla

Student Research Symposium

The purpose of this study is to model how 5-day weather patterns and algal buoyancy regulation influence the competition between two bloom forming cyanobacteria species in Upper Klamath Lake, Oregon. Sudden changes in weather patterns can quickly impact lake thermal structure, which can rapidly influence the competition between buoyancy regulating cyanobacteria. By modeling competition, I hope to address how altered climate would shift the competitive advantage to toxin forming cyanobacteria. I plan on accomplishing this by coupling a one-dimensional hydrodynamic and algal competition model, with lake specific physiological parameters. A sensitivity test of the model could reveal dramatic shifts in …