Physical Sciences and Mathematics Commons^™

Growing Reservoir Networks Using The Genetic Algorithm Deep Hyperneat, Nancy L. Mackenzie

Student Research Symposium

Typical Artificial Neural Networks (ANNs) have static architectures. The number of nodes and their organization must be chosen and tuned for each task. Choosing these values, or hyperparameters, is a bit of a guessing game, and optimizing must be repeated for each task. If the model is larger than necessary, this leads to more training time and computational cost. The goal of this project is to evolve networks that grow according to the task at hand. By gradually increasing the size and complexity of the network to the extent that the task requires, we will build networks that are more …

Using Digital Holographic Microscopy To Characterize Vibrio's Chemotaxis, Jacqueline Acres, Eric Valentino

Student Research Symposium

Vibrio alginolyticus is a marine bacterium that displays distinctive chemotactic behavior. Chemotaxis is the ability to move in response to a concentration gradient, either in the direction of nutrients or away from repellants. Vibrio's single, polar flagellum allows it to form a tight cloud in the presence of a chemoattractant. In this work, we experimentally characterize cloud sizes after both normal culture conditions and simulated microgravity using digital holographic microscopy or DHM. DHM allows visualization of volumetric samples by recording x,y,z and t information in holograms. Plane-by-plane reconstruction retrieves the z-plane information which can then by stitched together into hyperstacks …

Simple Arenes As Aryne Synthetic Equivalents Via Sulfonium Salt Intermediates, Riley A. Roberts

Student Research Symposium

Arynes are ephemeral molecules that are yet to be fully exploited in synthetic strategy because they are often challenging to access. These reactive intermediates participate in a myriad of reactions that conventional chemistry is incapable of, making them extremely useful for the synthesis of important molecules like pharmaceuticals and agrochemicals. While classical approaches for synthesizing arynes employ cheap starting material, extremely harsh reagents are necessary to generate the aryne. In contrast, methods that do not require harsh reaction conditions do require starting material that is exceedingly difficult to synthesize. To access arynes quickly and efficiently, the work described herein aims …

Mapping Ecosystem Service Flows Of Estuary Restoration Projects On The Oregon Coast To Identify Impacted Stakeholders, Shersten Finley

Student Research Symposium

Restoration of largely depleted estuarine systems is increasingly recognized as key to solving a variety of problems coastal communities face currently. Many of these issues will become more acute with climate change and sea level rise. Historic losses of estuary area, and recognition of the ecosystem services provided by functioning estuary ecosystems have resulted in current impetus to pursue estuary restoration. By mapping the flows of ecosystem services using three ecosystem service ‘scorecard’ categories pertaining to coastal resource management: recreation, aesthetics, and cultural/historical/spiritual, we gain a better understanding of the populations impacted by the changes in flows of ecosystem service …

Surface Plasmon Characterization In Ag Nanotriangles For Evaluation Of Fano Resonance Conditions, Nabila Islam

Student Research Symposium

Surface plasmon polariton (SPP) is a collective oscillation of electrons and light at the metal -dielectric interface excited by the incident radiation on metal surface through the momentum matching conditions. The properties of SPPs and the resonance conditions are highly dependent on the confining materials and geometry of the confining nanostructure. The sensitivity of the surface plasmon resonance to the property of the confining materials made Surface plasmon resonance (SPR) sensors a central tool for biosensing. However, the frequency resolution of SPR sensors is typically limited by the broad resonance of the SPR mode. The resolution can be enhanced through …

Stakeholder Perceptions Of Microplastics Management In Oregon, Maya A. Hurst-Mayr

Student Research Symposium

There is currently no federal policy in the United States that specifically addresses microplastics (MPs) pollution. However, states are beginning to act on this issue; California’s SB 1422 initiates measurement of MPs in drinking water resources and Senate Bill 1263 requires the state to adopt a strategy to reduce the ecological impact of MPs in marine ecosystems. Other West Coast states like Oregon and Washington are expected to follow California’s example. It is important to know what the actors who are a part of shaping MPs policy in Oregon would see as barriers and opportunities to doing so. We conducted …

Computational Investigation Of The Mechanism Of An Octahedral Ni(Ii) Proton Reduction Catalyst And Importance Of Intramolecular Hydrogen Bonding, Avik Bhattacharjee, Dayalis S.V. Brown, Carolyn N. Virca, Trent E. Ethridge, Oreana Mendez Galue, Uyen T. Pham, Theresa M. Mccormick

Student Research Symposium

Water-splitting to make hydrogen gas is of extreme importance in the field of alternative energy research. Transition-metal complexes are capable of catalyzing the conversion of water to hydrogen at higher pH, with low overpotential. Our research focuses on the importance of intramolecular hydrogen bonding (H-bonding) on the pKa and thermodynamic stability of the catalytic intermediates of a well-known proton-reduction catalyst, nickel (II) tris-pyridinethiolate. Density Functional Theory (DFT) calculations on the parent catalyst and eleven derivatives demonstrate geometric isomer formation after the protonation step of catalysis. These isomers differ in the relative thermodynamic stabilities and pKa values, which can be attributed …

Analysis Of Aftershock Parameters For The Alaskan Subduction Zone Tectonic Region, Gabrielle M. Paris (They/Them), Richard C. Hugo, Andrew J. Michael

Student Research Symposium

On 29 July 2021, a magnitude 8.2 earthquake was felt by over 200 people near Perryville, Alaska. The early aftershock forecasts issued by the USGS use default parameters based on expected productivity within a given tectonic region. These forecasts predicted a slower decrease in aftershock activity than what was observed. Even after the USGS adjusted the aftershock forecast parameters, the forecasts did not improve in the long term. Accurate aftershock predictions are important for maintaining public confidence in disaster alert systems. The question I want to explore is: are the generic parameters used in aftershock forecasting accurately describing the observed …

Cluster Chondrite Accretion Temperatures Determined With Electron Backscatter Diffraction, Secana Goudy, Alexander Ruzicka

Student Research Symposium

We studied ordinary chondrites with cluster chondrite lithologies using electron backscatter diffraction to measure the temperatures of their olivine grains during deformation. Samples analyzed with the technique are shock classified as S1 and are type 3, so the deformation analyzed is inferred to represent the temperatures of the chondrules during accretional deformation. It was found that the studied samples are of a mixture of chondrules at mostly hot temperatures (>850°C) and some at cold.

Predictive Validity Of A New Self-Report Measure Of Individual Skin Type Through Characterization Of Skin Melanin Using Reflectance Photospectroscopy, Mark Sanchez, Lisa Marriott, Teala Alvord, R. Samatham, S. Chang

Student Research Symposium

In the realm of research and dermatology, the Fitzpatrick Skin Type scale (FST) has been the gold standard of measurement to classify sun sensitivity for human’s skin. This scale is based on an individual’s dermal reaction to ultraviolet exposure (Parrish, et al., 1974; Fitzpatrick, 1975; Pathak, et al., 1976; Fitzpatrick, 1988). It was assumed in science as well as popular culture that individuals with darker skin were less susceptible to issues related to UV damage of their skin. More recent research (Eilers, et al., 2013) suggests that while melanin affords some skin protection, damage can still occur that may result …

Glacial Meltwater Modeling To Simulate Streamflow And Lake Levels In Taylor Valley, Antarctica, Julian M. Cross, Andrew G. Fountain

Student Research Symposium

The McMurdo Dry Valleys (MDV) are the largest ice-free region (4,500 km²) in Antarctica. The MDV are a polar desert with an average annual temperature of -18˚C and minimal precipitation, < 50 mm w.e. a^-1. In Taylor Valley (77°35’ S, 163°00’ E), a closed-basin, perennially ice-covered lakes occupy the valley floor. Ephemeral streams transfer glacier meltwater for ~10 weeks each summer. Glacial meltwater accounts for nearly the total inflow to these streams and lakes, groundwater is essentially non-existent. A microbially-dominated ecosystem in Taylor Valley depends on glacier runoff and thus is highly sensitive to changes to the hydroclimatic regime. A model …

Exploring And Expanding The One-Pixel Attack, Umairullah Khan, Walt Woods, Christof Teuscher

Student Research Symposium

In machine learning research, adversarial examples are normal inputs to a classifier that have been specifically perturbed to cause the model to misclassify the input. These perturbations rarely affect the human readability of an input, even though the model’s output is drastically different. Recent work has demonstrated that image-classifying deep neural networks (DNNs) can be reliably fooled with the modification of a single pixel in the input image, without knowledge of a DNN’s internal parameters. This “one-pixel attack” utilizes an iterative evolutionary optimizer known as differential evolution (DE) to find the most effective pixel to perturb, via the evaluation of …

Development Of A Design Guideline For Pile Foundations Subjected To Liquefaction-Induced Lateral Spreading, Milad Souri, Arash Khosravifar

Student Research Symposium

Past earthquakes confirmed that seismically induced kinematic loads from soil lateral spreading and inertial loads from structure can cause severe damages to pile foundations. The research questions are:

• How to combine inertial and kinematic loads in design of pile foundations in liquefied soil?
• How the combination of inertia and kinematics changes with depth?
• How this combination is affected by long-duration earthquakes?
• How this combination affects inelastic demands in piles?

Arbuscular Mycorrhizal Fungi Associations Across Multiple Saltmarsh Plant Species Mitigating The Impacts Of Sea-Level Rise, Rayna Koberstein, Catherine E. De Rivera

Student Research Symposium

Sea level rise caused by climate change will detrimentally impact saltmarsh habitats by increasing the elevation and rate of terrestrial salt water inundation, thereby reducing effective functionality of ecosystem services provided by saltmarshes. Facilitation is key to community structuring and function in habitats characterized by abiotic stress, such as salt marshes. Halophytic plants within salt marshes can benefit from symbiotic arbuscular mycorrhizal fungi (AMF) facilitations through increased inundation tolerance, greater nutrient availability and uptake, alleviation from drought stress and relief from saline stress.

Through this research, land managers developing sea-level rise mitigation plans will have data supporting which plants will …

Are We Providing The Preferred Floral Resources For Bees In Our Neighborhoods? Relationships Between Small Scale Vegetation Metrics And Pollinator Visitation In Se Portland, Hailey Wallace, Marion Dresner

Student Research Symposium

Due to the threat of losing our pollinators, there are many conservation actions such as "pollinator friendly" areas being constructed in cities around the globe, because of this there is a need for a greater understanding of the relationship between bees, and floral resources at a local landscape level. I assessed the relationship between blossom density, inflorescence type, cover, frequency, density and numbers of bees observed at three different "pollinator friendly" areas in South East Portland. This project utilized community science members to gather observational monitoring data at Johnson Creek Commons Rain Garden, SE Yukon Bioswales and Beyer Court Rain …

Effects Of Wavelength Variation On Localized Photoemission In Triangular Gold Antennas, Christopher M. Scheffler, Robert Campbell Word, Rolf Könenkamp

Student Research Symposium

Exposing metal-dielectric structures to light can result in surface plasmon excitation and propagation along the transition interface, creating a surface plasmon polariton (SPP) response. Photoemission electron microscopy (PEEM) has been used to image nanometer scale plasmonic responses in micron-sized plasmonic devices. With PEEM, optical responses can be characterized in detail, aiding in the development of new types of plasmonic structures and their applications. In thin, triangular gold platelets SPPs can be excited and concentrated within specific regions of the material. In this regard, the platelets act as receiver antennas by converting the incident light into localized excitations in specific regions …

Assessment Of Observed Increases In Extreme Warm Exceedances In Locations With Short Warm Side Tails, Jacob S. Hunter, Paul C. Loikith, J. David Neelin

Student Research Symposium

Regions of shorter-than-Gaussian temperature distribution tails have been shown to occur in spatially coherent patterns in the current climate using reanalysis. Under such conditions, future changes in extremes due to global warming may manifest in more complex ways than if the underlying distribution were closer to Gaussian. For instance, under a uniform warm shift, the simplest prototype for future warming, a location with a short warm side tail would experience a greater increase in exceedances than if the distribution were Gaussian. This carries meaningful societal and environmental implications including but not limited to negative impacts on human and ecosystem health, …

Diagnostic Platform For Current Health Status Monitoring, Albert S. Benight, Megan M. Koslen, Matthew W. Eskew

Student Research Symposium

Our approach is based on physical measurements of blood plasma and exploits the plethora of information contained in the human plasma proteome, as a reporter of human health status. The assay involves collection and analysis ofthermograms of plasma from human blood measured by differential scanning calorimetry (DSC).

Plasma thermograms arise from the temperature-induced denaturation profile of proteins within blood plasma measured by DSC. This insightful measurement thereby provides a snapshot of the current state of the human plasma proteome which directly informs on overall systemic health. Such measurements have been shown to be highly accurate and sensitive indicators of health …

Metallodithiolate Ligands For Reversing Metal Ion Induced Aggregation Of Beta Amyloid, Eleanor K. Adams, Marilyn Rampersad Mackiewicz

Student Research Symposium

Alzheimer’s Disease (AD) is the sixth leading cause of death in the United States with no known methods to cure, reverse or halt disease progression. The “metal hypothesis” states that Fe^II, Cu^II, Zn^II, and Al^II bind to truncated Aβ peptides and form soluble oligomers which deposit as senile plaques. These plaques play a crucial role in AD pathogenesis. For example, metallated-Aβ aggregates are hypothesized to disrupt membranes or generate a reactive oxygen species (ROS) through redox cycling in the presence of Cu^I/II or Fe^III/II and a reducing agent. ROS can lead …

Estimating Sand Loss: Using Eolian Sand Ramps As A Proxy For Estimating Past Erosion Within The Lincoln City Dune Sheet; Lincoln City, Oregon, Kara E. P. Kingen, John Bershaw, Curt D. Peterson

Student Research Symposium

Eolian sand ramps are features that are sculpted from beach sand blowing up against sea cliffs or bluffs. In some coastal areas, sand ramp deposits only appear as the erosional remnants of pre-existing ramps that have been truncated at eroded shorelines, separating them from their previous sediment supply. Although sand ramp features have been observed in other areas on the western coast of the United States , they had not been studied or documented within the Lincoln City Dune Sheet (LINC) prior to this study – which documents the existence of truncated eolian sand ramps in LINC and uses them …

Opportunities In Physics Education: Low-Cost Position Tracking For Use In Kinematics Labs, Paul R. Destefano, Cora Siebert, Roberto Perez-Franco, Thomas Allen, Gabriel Mukobi, Ralf Widenhorn

Student Research Symposium

Traditional introductory physics kinematics laboratories utilized a few different instruments for locating objects in motion, all of which have shortcomings. Some provide only timing data, which heavily restricts trajectories and data collection. Some instruments provide more measurements but restrict object shapes, orientations, and textures. Still others require extensive pre-processing. None of these traditional instruments provide two- or three-dimensional position data. New, low-cost, local positioning technology, based on radio frequency wireless communications, is available that enables novel redesigns of physics laboratories. This technology provides two- and three-dimensional position measurements, continuously, at data rates of 10 Hz or faster, from any object …

Clustering And Multifacility Location With Constraints Via Distance Function Penalty Methods And Dc Programming, Tuyen Tran, Samuel Reynolds, Thai An Nguyen, Mau Nam Nguyen

Student Research Symposium

This is a continuation of our effort in using mathematical optimization involving DC programming in clustering and multifacility location. We study a penalty method based on distance functions and apply it particularly to a number of problems in clustering and multi- facility location in which the centers to be found must lie in some given set constraints. We also provide numerical examples to test our method.

Using Reservoir Computing To Build A Robust Interface With Dna Circuits In Determining Genetic Similarities Between Pathogens, Christopher Neighbor, Christof Teuscher

Student Research Symposium

As computational power increases, the field of neural networks has advanced exponentially. In particular recurrent neural networks (RNNs) are being utilized to simulate dynamic systems and to learn to predict time series data. Reservoir computing is an architecture which has the potential to increase training speed while reducing computational costs. Reservoir computing consists of a RNN with a fixed connections “reservoir” while only the output layer is trained. The purpose of this research is to explore the effective use of reservoir computing networks with the eventual application towards use in a DNA based molecular computing reservoir for use in pathogen …

Find, Build, And Export Information For 3d Printing Of Your Favorite Molecules And Crystal Structures At Two Dedicated Websites, Paul R. Destefano, Peter Moeck

Student Research Symposium

As 3D printers require instructions, the Nano-Crystallography Group at Portland State University is creating two websites (http://nanocrystallography.org/3dconvert/ and http://nanocrystallography.research.pdx.edu/3d-print-files/convert/) where such instructions are created, interactively, for the atomic arrangements of virtually all known molecules and crystals.

We will prepare a "pipeline" into which crystallographic information enters from two curated open access crystallographic databases, is manipulated to create the desired 3D models, and then is exported in either STL format (the standard for monochrome 3D printing) or VRML/X3D (the ISO successor to STL). The two aforementioned databases are the North-American mirror of the Crystallography Open Database (http://nanocrystallography.org) …

Bayesian Optimization For Refining Object Proposals, With An Application To Pedestrian Detection, Anthony D. Rhodes

Student Research Symposium

We devise an algorithm using a Bayesian optimization framework in conjunction with contextual visual data for the efficient localization of objects in still images. Recent research has demonstrated substantial progress in object localization and related tasks for computer vision. However, many current state-of-the-art object localization procedures still suffer from inaccuracy and inefficiency, in addition to failing to successfully leverage contextual data. We address these issues with the current research.

Our method encompasses an active search procedure that uses contextual data to generate initial bounding-box proposals for a target object. We train a convolutional neural network to approximate an offset distance …

Non-Native Mangroves Of Moloka'i, Hawai'i: A Socio-Ecological Analysis, Casey Lewis

Student Research Symposium

Invasive species are recognized as a leading threat to ecosystems and their management is expensive, time consuming, and labor intensive. Therefore, it is important to review both benefits and detriments of the species to inform appropriate management decisions. Red mangrove was introduced to Moloka'i, Hawaii in 1902 to mitigate the effects of soil erosion and has since spread along the coast and to adjacent islands creating novel habitat. This study assessed both biological services and social attitudes towards Moloka'i's non-native mangroves to provide a comprehensive evaluation of the species. Zooplankton community structure was examined in mangrove and non-mangrove sites and …

Quasi-Optical Measurement For Low Loss Material Characterization In Submillimeter Wave Range, Ha Khiem Tran, Thanh Ngoc Dan Le, Branimir Pejcinovic

Student Research Symposium

An accurate knowledge of dielectric constant of materials is required in many sub-millimeter wave applications. Free-space measurement of materials has always been one of the first choices due to their non-destructive nature and relatively simple sample preparation. However, free-space measurement systems at sub-millimeter frequency range suffer from two main problems: high loss because of divergent beam pattern and diffraction when the beam waist of the radiated beam is relatively large compared to the size of the sample under tests. In order to mitigate these issues, we set up a quasi-optical system using off-axis parabolic mirrors, which enhance the dynamic range …

The Importance Of Urban Habitat Connectivity And Influence On Native Avian Species And Community Science, Kristen S. Gulick

Student Research Symposium

In what ways do small-scale urban backyards contribute to local bird abundance and biodiversity? In what ways might these yards serve as an ‘extension’ of neighboring native forest areas? This project investigates the contribution that a group of backyards, certified through the Backyard Habitat Certification Program, have in the suburb of Hillsdale, Oregon, which is adjacent to the natural area of Keller Woodland. Backyard owners functioning as citizen or community scientists assisted with conducting residential bird point-counts once a week in each backyard and the natural area. Counts were done for a total of 8 weeks during nesting season to …

Performance Analysis Of Droughthpc, Yasodhadevi Nachimuthu

Student Research Symposium

We present our performance analysis of DroughtHPC, a software application being developed by an interdisciplinary effort lead by Dr.Moradkhani in the Civil Engineering department, Dr. Daescu in the Math Department, and Dr. Karavanic in the Computer Science Department.

The DroughtHPC application is used to predict drought conditions for a target geographical area. The data used in the prediction are soil conditions, vegetation layers, canopy cover, snow accumulation information from satellites, and meteorological data. DroughtHPC is written in Python and uses two hydrologic models, PRMS [1] and VIC [2], to simulate soil moisture levels. A larger geographical area such as the …

Finite Element Method Analysis Of Resonant Cavity For Whispering Gallery Acoustic Sensing Microscopy, Thanh N.D. Le, Ha Tran, Andres H. La Rosa

Student Research Symposium

Whispering Gallery Acoustic Sensing (WGAS) has been studied by Department of Physics at Portland State University as a mean of controlling sample to probe distance in tuning-folk-based scanning probe microscopy (TF-SPM). WGAS uses the microscope frame as a resonance acoustic cavity. The setup shows high potential because of high-quality factor nature of acoustic cavity as well as using mechanical motions of the TF itself instead of electrical signals. However, the analytic solution of the eigenfrequencies of the current microscope frame is very complex due to the asymmetric geometry. The purpose of this study is to use finite element method to …