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Portland State University

REU Final Reports

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Articles 1 - 10 of 10

Full-Text Articles in Physical Sciences and Mathematics

Simulating Dislocation Densities With Finite Element Analysis, Ja'nya Breeden, Dow Drake, Saurabh Puri Aug 2021

Simulating Dislocation Densities With Finite Element Analysis, Ja'nya Breeden, Dow Drake, Saurabh Puri

REU Final Reports

A one-dimensional set of nonlinear time-dependent partial differential equations developed by Acharya (2010) is studied to observe how differing levels of applied strain affect dislocation walls. The framework of this model consists of a convective and diffusive term which is used to develop a linear system of equations to test two methods of the finite element method. The linear system of partial differential equations is used to determine whether the standard or Discontinuous Galerkin method will be used. The Discontinuous Galerkin method is implemented to discretize the continuum model and the results of simulations involving zero and non-zero applied strain …


Spatial Analysis Of Landscape Characteristics, Anthropogenic Factors, And Seasonality Effects On Water Quality In Portland, Oregon, Katherine Gelsey, Daniel Ramirez Aug 2021

Spatial Analysis Of Landscape Characteristics, Anthropogenic Factors, And Seasonality Effects On Water Quality In Portland, Oregon, Katherine Gelsey, Daniel Ramirez

REU Final Reports

Urban areas often struggle with deteriorated water quality as a result of complex interactions between landscape factors such as land cover, use, and management as well as climatic variables such as weather, precipitation, and atmospheric conditions. Green stormwater infrastructure (GSI) has been introduced as a strategy to reintroduce pre-development hydrological conditions in cities, but questions remain as to how GSI interacts with other landscape factors to affect water quality. We conducted a statistical analysis of six relevant water quality indicators in 131 water quality stations in four watersheds around Portland, Oregon using data from 2015 to 2021. Indiscriminate of station …


Digitally Reporting Trail Obstructions In Forest Park, Colton S. Maybee Aug 2021

Digitally Reporting Trail Obstructions In Forest Park, Colton S. Maybee

REU Final Reports

The inclusion of technology on the trail can lead to better experiences for everyone involved in the hobby. Hikers can play a more prominent role in the maintenance of the trails by being able to provide better reports of obstructions while directly on the trail. This paper goes into the project of revamping the obstruction report system applied at Forest Park in Portland, Oregon. Most of my contributions to the project focus on mobile app development with some research into path planning algorithms related to the continuations of this project.


Forest Park Trail Monitoring, Adan Robles, Colton S. Maybee, Erin Dougherty Aug 2021

Forest Park Trail Monitoring, Adan Robles, Colton S. Maybee, Erin Dougherty

REU Final Reports

Forest Park, one of the largest public parks in the United States with over 40 trails to pick from when planning a hiking trip. One of the main problems this park has is that there are too many trails, and a lot of the trails extend over 3 miles. Due to these circumstances’ trails are not checked frequently and hikers are forced to hike trails in the area with no warnings of potential hazards they can encounter. In this paper I researched how Forest Park currently monitors its trails and then set up a goal to solve the problem. We …


Modeling The Defects That Exists In Crystalline Structures, Kiet A. Tran Aug 2019

Modeling The Defects That Exists In Crystalline Structures, Kiet A. Tran

REU Final Reports

This paper focuses on modeling defects in crystalline materials in one-dimension using field dislocation mechanics (FDM). Predicting plastic deformation in crystalline materials on a microscopic scale allows for the understanding of the mechanical behavior of micron-sized components. Following Das et al (2013), a one dimensional reduction of the FDM model is implemented using Discontinuous Galerkin method and the results are compared with those obtained from the finite difference implementation. Test cases with different initial conditions on the position and distribution of screw dislocations are considered.


Discretization Of The Hellinger-Reissner Variational Form Of Linear Elasticity Equations, Kevin A. Sweet Aug 2019

Discretization Of The Hellinger-Reissner Variational Form Of Linear Elasticity Equations, Kevin A. Sweet

REU Final Reports

This paper addresses the derivation of the Hellinger-Reissner Variational Form from the strong form of a system of linear elasticity equations that are used in relation to geological phenomena. The problem is discretized using finite element discretization. This allowed the creation of a program that was used to run tests on various domains. The resultant displacement vectors for tested domains are shown at the end of the paper.


A Resource Constrained Shortest Paths Approach To Reducing Personal Pollution Exposure, Elling Payne Jun 2019

A Resource Constrained Shortest Paths Approach To Reducing Personal Pollution Exposure, Elling Payne

REU Final Reports

As wildfires surge in frequency and impact in the Pacific Northwest, in tandem with increasingly traffic-choked roads, personal exposure to harmful airborne pollutants is a rising concern. Particularly at risk are school-age children, especially those living in disadvantaged communities near major motorways and industrial centers. Many of these children must walk to school, and the choice of route can effect exposure. Route-planning applications and frameworks utilizing computational shortest paths methods have been proposed which consider personal exposure with reasonable success, but few have focused on pollution exposure, and all have been limited in scalability or geographic scope. This paper addresses …


Derivation Of The Hellinger-Reissner Variational Form Of The Linear Elasticity Equations, And A Finite Element Discretization, Bram Fouts Jan 2018

Derivation Of The Hellinger-Reissner Variational Form Of The Linear Elasticity Equations, And A Finite Element Discretization, Bram Fouts

REU Final Reports

In this paper we are going to derive the linear elasticity equations in the Strong Form to the Hellinger Reissner Form. We find a suitable solution to solve our stress tensor. Then we will use finite element discretization from. We will run tests on a unit cube and multiple other shapes, which are described at the end. We view the different magnitudes of the displacement vector of each shape.


Day Laborers & Extreme Heat: Recommendations For Reducing Heat Stress, Sandra Mena Jan 2018

Day Laborers & Extreme Heat: Recommendations For Reducing Heat Stress, Sandra Mena

REU Final Reports

The Intergovernmental Panel on Climate Change (IPCC) has various Global Climate Models (GCM). One of them, models three greenhouse gases. The increasing amount of greenhouse gases are just a fraction of factors that fuel global climate change. According to the IPCC 2014, climate related extremes such as heatwaves are likely to occur more regularly and are likely to increase in duration. Since 1979, there has been over 9000 deaths that occurred from heat-related incidents in the United States (U.S. Environmental Protection Agency, 2016). Which brings attention to population groups who are exposed to hot temperatures on a frequent basis due …


Effects Of Land Development And Season On Heavy Metal Concentrations In Urban Streams, Helen Daigle Jan 2018

Effects Of Land Development And Season On Heavy Metal Concentrations In Urban Streams, Helen Daigle

REU Final Reports

Although it is generally understood that urban development can impact the quality of urban streams, there are many factors that affect the concentrations of pollutants being transferred from the built environment to a given output. This study examines the impact of land use surrounding urban streams, specifically, the degree of development and presence or absence of green infrastructure (GI) in these areas on heavy metal (HM) concentrations in Portland, Oregon. After collecting 1021 water quality samples from 2010-2018, we examined the difference in concentrations of HM pollutants across different combinations of land use and season. Increased levels of calcium, magnesium, …