Physical Sciences and Mathematics Commons^™

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 …

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 …

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 …

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.

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 …

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 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 …

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 …

Collecting Image Cropping Dataset: A Hybrid System Of Machine And Human Intelligence, Uyen T. Mai, Feng Liu

Student Research Symposium

Image cropping is a common tool that exists in almost any image editor, yet automatic cropping is still a difficult problem in Computer Vision. Since images nowadays can be easily collected through the web, machine learning is a promising approach to solve this problem. However, an image cropping dataset is not yet available and gathering such a large-scale dataset is a non-trivial task. Although a crowdsourcing website such as Mechanical Turk seems to be a solution to this task, image cropping is a sophisticated task that is vulnerable to unreliable annotation; furthermore, collecting a large-scale high-quality dataset through crowdsourcing is …

Identifying Relationships Between Scientific Datasets, Abdussalam Alawini

Dissertations and Theses

Scientific datasets associated with a research project can proliferate over time as a result of activities such as sharing datasets among collaborators, extending existing datasets with new measurements, and extracting subsets of data for analysis. As such datasets begin to accumulate, it becomes increasingly difficult for a scientist to keep track of their derivation history, which complicates data sharing, provenance tracking, and scientific reproducibility. Understanding what relationships exist between datasets can help scientists recall their original derivation history. For instance, if dataset A is contained in dataset B, then the connection between A and B could be that A was …

Understanding The Optical Properties Of Ambient Sub-And Supermicron Particulate Matter: Results From The Cares 2010 Field Study In Northern California, Christopher D. Cappa, Katheryn R. Kolesar, Xiaolu Zhang, Dean B. Atkinson, Mikhail S. Pekour, Rahul A. Zaveri, Alla Zelenyuk, Qi Zhang

Chemistry Faculty Publications and Presentations

Measurements of the optical properties (absorption, scattering and extinction) of PM1, PM2.5 and PM10 made at two sites around Sacramento, CA, during the June 2010 Carbonaceous Aerosols and Radiative Effects Study (CARES) are reported. These observations are used to establish relationships between various intensive optical properties and to derive information about the dependence of the optical properties on photochemical aging and sources. Supermicron particles contributed substantially to the total light scattering at both sites, about 50 % on average. A strong, linear relationship is observed between the scattering Ångström exponent for PM10 and the fraction of the scattering that is …

The Value Of Long-Term Stream Invertebrate Data Collected By Citizen Scientists, Patrick M. Edwards

Environmental Science and Management Faculty Publications and Presentations

The purpose of this investigation was to systematically examine the variability associated with temporally-oriented invertebrate data collected by citizen scientists and consider the value of such data for use in stream management. Variability in invertebrate data was estimated for three sources of variation: sampling, within-reach spatial and long-term temporal. Long-term temporal data were also evaluated using ordinations and an Index of Biotic Integrity (IBI). Through two separate investigations over an 11-year study period, participants collected more than 400 within-reach samples during 44 sampling events at three streams in the western United States. Within-reach invertebrate abundance coefficient of variation (CV) ranged …

Geogenic Cadmium Pollution And Potential Health Risks, With Emphasis On Black Shale, Yizhang Liu, Tangfu Xiao, Robert Perkins, Jianming Zhu, Zhengjie Zhu, Yan Xiong, Zengping Ning

Geology Faculty Publications and Presentations

Cadmium (Cd) is a non-essential trace element that is toxic to humans. Previous studies of Cd in the environment have primarily focused on pollution resulted from anthropogenic sources, but little is known on naturally occurring sources of Cd. This paper aims to review the geochemical distribution of geogenic Cd and associated environmental risk. The source, accumulation, mobility, transportation, and health risk of Cd are discussed in a geo-environmental perspective, with an emphasis on black shale soils. Cadmium generally occurs in sulfides in black shale, and is easily released when exposed to oxygen and water. Leaching of these rocks tends to …

Spatial And Temporal Variability Of Contaminants Within Estuarine Sediments And Native Olympia Oysters: A Contrast Between A Developed And An Undeveloped Estuary, Elise F. Granek, Kathleen E. Conn, Elena B. Nilsen, Lori Pillsbury, Angela L. Strecker, Steven S. Rumrill, William Fish

Environmental Science and Management Faculty Publications and Presentations

Chemical contaminants can be introduced into estuarine and marine ecosystems from a variety of sources including wastewater, agriculture and forestry practices, point and non-point discharges, runoff from industrial, municipal, and urban lands, accidental spills, and atmospheric deposition. The diversity of potential sources contributes to the likelihood of contaminated marine waters and sediments and increases the probability of uptake by marine organisms. Despite widespread recognition of direct and indirect pathways for contaminant deposition and organismal exposure in coastal systems, spatial and temporal variability in contaminant composition, deposition, and uptake patterns are still poorly known. We investigated these patterns for a suite …

Temporal Variations Of Citizens’ Demands On Flood Damage Mitigation, Streamflow Quantity And Quality In The Korean Urban Watershed, Change-Yu Hong, Eun-Sung Chung

Urban Studies and Planning Faculty Publications and Presentations

Sustainable watershed management (SWM) can be achieved through recognition and reflection upon the values of citizens. Collaborative governance consisting of citizens is crucial for successful SWM. Collaborative governance definitely requires an active participatory decision-making process that reflects citizens’ preferences. Citizen preference also tends to substantially change with life pattern and life quality. These shifts can be caused by slight variations in both social priorities and personal preferences for SWM. Therefore, collaborative water governance must be frequently renewed in response to citizens’ values through the participatory framework. The An’yang Stream in South Korea is generally regarded as a representative urban stream …

A Chemistry Neutral Flow Battery Performance Model Development, Validation, And Application, Alasdair James Crawford

Dissertations and Theses

A physical model for redox flow batteries is developed to estimate performance for any chemistry using parameters such as electrolyte conductivity and kinetic rate constants. The model returns the performance as a function of flow rate, current density, and state of charge. Two different models are developed to estimate the current density distribution throughout the electrode in order to evaluate physical performance of the battery. This is done using electrochemical parameters such as conductivity and kinetic rate constant. The models are analytical in order to produce a computationally cheap algorithm that can be used in optimization routines. This allows for …

How Landscape Ecology Informs Global Land-Change Science And Policy, Audrey L. Mayer, Brian Buma, Amélie Davis, Sara A. Gagné, E. Louise Loudermilk, Robert M. Scheller, Fiona K.A. Schmiegelow, Fiona Majorin, Yolanda F. Wiersma, Janet Franklin

Environmental Science and Management Faculty Publications and Presentations

Landscape ecology is a discipline that explicitly considers the influence of time and space on the environmental patterns we observe and the processes that create them. Although many of the topics studied in landscape ecology have public policy implications, three are of particular concern: climate change; land use–land cover change (LULCC); and a particular type of LULCC, urbanization. These processes are interrelated, because LULCC is driven by both human activities (e.g., agricultural expansion and urban sprawl) and climate change (e.g., desertification). Climate change, in turn, will affect the way humans use landscapes. Interactions among these drivers of ecosystem change can …

A Behavior-Based Framework For Assessing Barrier Effects To Wildlife From Vehicle Traffic Volume, Sandra L. Jacobson, Leslie L. Bliss-Ketchum, Catherine E. De Rivera, Winston P. Smith

Environmental Science and Management Faculty Publications and Presentations

Roads, while central to the function of human society, create barriers to animal movement through collisions and habitat fragmentation. Barriers to animal movement affect the evolution and trajectory of populations. Investigators have attempted to use traffic volume, the number of vehicles passing a point on a road segment, to predict effects to wildlife populations approximately linearly and along taxonomic lines; however, taxonomic groupings cannot provide sound predictions because closely related species often respond differently. We assess the role of wildlife behavioral responses to traffic volume as a tool to predict barrier effects from vehicle-caused mortality and avoidance, to provide an …

The Biological Sediment Tolerance Index: Assessing Fine Sediments Conditions In Oregon Streams Using Macroinvertebrates, Shannon Hubler, David Huff, Patrick M. Edwards, Yangdong Pan

Environmental Science and Management Faculty Publications and Presentations

Fine sediments in excess of natural background conditions are one of most globally common causes of stream degradation, with well documented impacts on aquatic communities. The lack of agreement on methods for monitoring fine sediments makes it difficult to share data, limiting assessments of stream conditions across jurisdictions. We present a model that circumvents these limitations by inferring fine sediments in Oregon streams through sampling of macroinvertebrates. Tolerances to fine sediments (

Bridge Over Troubled Waters: A Synthesis Session To Connect Scientific And Decision Making Sectors, Kaitlin Goldsmith, Elise F. Granek, Amy Lubitow, Michael Papenfus

Environmental Science and Management Faculty Publications and Presentations

Lack of access to relevant scientific data has limited decision makers from incorporating scientific information into their management and policy schemes. Yet, there is increasing interest among decision makers and scientists to integrate coastal and marine science into the policy and management process. Strategies designed to build communication between decision makers and scientists can be an effective means to disseminate and/or generate policy relevant scientific information. Here researchers develop, test, and present a workshop model designed to bridge the gap between coastal and marine decision makers and scientists. Researchers identify successful components of such a workshop as well as areas …

More Investigations In Capillary Fluidics Using A Drop Tower, Andrew Paul Wollman, Mark M. Weislogel, Brentley M. Wiles, Donald Pettit, Trevor Snyder

Mechanical and Materials Engineering Faculty Publications and Presentations

A variety of contemplative demonstrations concerning intermediate-to-large length scale capillary fluidic phenomena were made possible by the brief weightless environment of a drop tower (Wollman and Weislogel in Exp Fluids 54(4):1, 2013). In that work, capillarity-driven flows leading to unique spontaneous droplet ejections, bubble ingestions, and multiphase flows were introduced and discussed. Such efforts are continued herein. The spontaneous droplet ejection phenomena (auto-ejection) is reviewed and demonstrated on earth as well as aboard the International Space Station. This technique is then applied to novel low-g droplet combustion where soot tube structures are created in the wakes of burning drops. …

Arsenic Mobilization From Silicic Volcanic Rocks In The Southern Willamette Valley, Gabriela Ribeiro De Sena Ferreira

Dissertations and Theses

Volcanic tuffs and tuffaceous sediments are frequently associated with elevated As groundwater concentrations even though their bulk As contents (~ 5 mg kg^-1; Savoie, 2013) are only marginally greater than the average crustal abundance of 4.8 mg g^-1 (Rudnick & Gao, 2003). Thus, As mobilization must be facilitated by conditions particular to these rocks. Alkaline desorption, anionic competition, reactive glass dissolution, and reductive dissolution of iron oxides are proposed processes of As release from volcanic rocks. Geogenic As contamination of groundwater in the southern Willamette Valley in western Oregon has been well-documented since the early 1960s, and …

The Differing Biogeochemical And Microbial Signatures Of Glaciers And Rock Glaciers, Timothy S. Fegel, Jill S. Baron, Andrew G. Fountain, Gunnar F. Johnson, Ed K. Hall

Geology Faculty Publications and Presentations

Glaciers and rock glaciers supply water and bioavailable nutrients to headwater mountain lakes and streams across all regions of the American West. Here we present a comparative study of the metal, nutrient, and microbial characteristics of glacial and rock glacial influence on headwater ecosystems in three mountain ranges of the contiguous U.S.: the Cascade Mountains, Rocky Mountains, and Sierra Nevada. Several meltwater characteristics (water temperature, conductivity, pH, metals, nutrients, complexity of dissolved organic matter (DOM), and bacterial richness and diversity) differed significantly between glacier and rock glacier meltwaters, while other characteristics (Ca²+, Fe³+, SiO₂ concentrations, …

A Novel Methodology For Spatial Damage Detection And Imaging Using A Distributed Carbon Nanotube-Based Composite Sensor Combined With Electrical Impedance Tomography, Hongbo Dai, Gerard J. Gallo, Thomas Schumacher, Erik T. Thostenson

Civil and Environmental Engineering Faculty Publications and Presentations

This paper describes a novel non-destructive evaluation methodology for imaging of damage in composite materials using the electrical impedance tomography (EIT) technique applied to a distributed carbon nanotube-based sensor. The sensor consists of a nonwoven aramid fabric, which was first coated with nanotubes using a solution casting approach and then infused with epoxy resin through the vacuum assisted resin transfer molding technique. Finally, this composite sensor is cured to become a mechanically-robust, electromechanically-sensitive, and highly customizable distributed two-dimensional sensor which can be adhered to virtually any substrate. By assuming that damage on the sensor directly affects its conductivity, a difference …

The Biomolecule Sequencer Project: Nanopore Sequencing As A Dual-Use Technology For Crew Health And Astrobiology Investigations, K. K. John, D. S. Botkin, A. S. Burton, S. L. Castro-Wallace, J. D. Chaput, J. P. Dworkin, Niles Lehman, M. L. Lupisella, C. E. Mason, D. J. Smith, S. Stahl, C. Switzer

Chemistry Faculty Publications and Presentations

Human missions to Mars will fundamentally transform how the planet is explored, enabling new scientific discoveries through more sophisticated sample acquisition and processing than can currently be implemented in robotic exploration. The presence of humans also poses new challenges, including ensuring astronaut safety and health and monitoring contamination. Because the capability to transfer materials to Earth will be extremely limited, there is a strong need for in situ diagnostic capabilities. Nucleotide sequencing is a particularly powerful tool because it can be used to: (1) mitigate microbial risks to crew by allowing identification of microbes in water, in air, and on …