Digital Commons Network^™

Designing Particle Tracking Software For A Theoretical Understanding Of Magnetic Janus Particle Aggregation, Thomas W. Long

Dissertations and Theses

Magnetic Janus particles are spherical colloids covered with a thin magnetic cap on one half of their surface. The asymmetric magnetic material gives the particles a magnetic dipole shifted away from the center of mass of the particle. The magnetic dipole either points perpendicular (axially-shifted FexOy caps) or parallel (radially-shifted (Co/Pd)x multilayered particles) to the shift vector. When a magnetic field is applied to a system of magnetic Janus particles, the particles aggregate into chains aligned with the magnetic field. The rate of aggregation is of theoretical and practical interest and the focus of the thesis.

Optically studying samples of …

Towards Improving Accuracy And Interpretability Of Deep Learning Based On Satellite Image Classification, Yamile Patino Vargas

Dissertations and Theses

ABSTRACT

The study of satellite images provides a way to monitor changes in the surface of the Earth and the atmosphere. Convolutional Neural Networks (CNN) have shown accurate results in solving practical problems in multiple fields. Some of the more recognized fields using CNNs are satellite imagery processing, medicine, communication, transportation, and computer vision. Despite the success of CNNs, there remains a need to explain the network predictions further and understand what the network is determining as valuable information.

There are several frameworks and methodologies developed to explain how CNNs predict outputs and what their internal representations are [1, 4, …

A Dynamic Risk Management Framework For Water And Environmental Sustainability, Arun Ravindranath

Dissertations and Theses

The risks and vulnerabilities facing reservoir systems in river basins shift dynamically over time and space. These risks involve regime changes and shifts, throughout which one observes the transition of water availability from prolonged dry periods to prolonged wet periods. Ensuring reliability of water supply under these hydrological regime shifts involves understanding how these regime shifts can be identified, characterized, and quantified. This dissertation describes a dynamic risk management (DRM) framework for water management at the basin level whose main features are (1) a system of updating risk assessments and policy recommendations on a yearly basis, where the risk assessments …

Development Of Electromagnetic Friction Dampers For Improving Seismic Performance Of Civil Structures, Mohsen Amjadian

Dissertations and Theses

Energy dissipation is critical to limiting damage to civil structures subjected to extreme natural events such as earthquakes. Friction is one of the most reliable mechanisms of energy dissipation that has been utilized extensively in friction dampers to improve seismic performance of civil structures. Friction dampers are well-known for having a highly nonlinear hysteretic behavior caused by stick-slip motion at low velocities, a phenomenon that is inherent in friction and increases the acceleration response of the structure under control unfavorably, in spite of the fact that the displacement is generally reduced because of the energy dissipation. This increase in acceleration …

Revolution, Reform, And Class Conflict In Rebecca Harding Davis’S Life In The Iron-Mills, Thomas Collins

Dissertations and Theses

Life in the Iron-Mills (1861) by Rebecca Harding Davis is a very early example of American fiction that depicts the living and working conditions in a mill town. Although the novella advocates for workers, it does not accurately depict contemporaneous working-class culture. Davis depicts workers as isolated and helpless in the face of the forces that oppress them rather than giving voice to the workers’ movement of her time. Although Davis depicts workers in a debased state, the text’s narrator holds out hope of the “Dawn,” suggesting a revolutionary movement. Because the narrator offers no interpretation regarding how the working …

Affordances On Facebook, Stress, And Emotional Support, Caitlin Rose Rethwish

Dissertations and Theses

This study discusses Facebook as a social network site and a social media application. It compares perceived emotional support, general life stress, and media affordance-based stress from two participant samples - one that reported using the Facebook desktop site most frequently to reach out for emotional support, and one that reported using the mobile application.

The media affordance measure asked participants if perceiving a media affordance was more likely to increase or decrease their stress. In both samples, persistence was more likely to decrease stress, and personalization was more likely to increase stress. On the Facebook Desktop site, searchability was …

Small Rna Mgrr Regulates Sensitivity Of Escherichia Fergusonii To Oxidative Stress, Austin Paul Wright

Dissertations and Theses

Non-coding small RNAs (sRNAs) are integral to post-transcriptional gene regulation in bacteria. The function of an sRNA is dependent on both secondary structure and the sequence of its unstructured seed region. The sRNA seed region typically base-pairs with target mRNAs to down-regulate the expression of target genes by blocking the ribosome-binding site or by promoting RNase-mediated degradation of the sRNA-mRNA complex. sRNAs have also been shown to increase expression of target genes by releasing RNA secondary structures that block ribosome-binding sites. Selective pressure to maintain sRNA function conserves the sequence of the sRNA seed region, but mutations in mRNA sequences …

Consciousness Against Commodifcation: The Potential For A Radical Housing Movement In The Cully Neighborhood, Cameron Hart Herrington

Dissertations and Theses

A right to housing is a central iteration of the broader demand for a democratic right to the city. The perpetual housing crisis for lower-income people results from a commodified system in which access to housing is based on the exchange value interests of property owners, rather than a universal right to a decent, affordable home. This system is a pillar of neoliberal urban governance and justified by a hegemonic ideology that equates speculative homeownership with the American Dream. Achieving a right to housing, even at the local scale, requires a radical movement that cultivates individual and collective consciousness, discredits …

The Effect Of Styrene-Maleic Acid (Sma) Copolymers On Solubilizing Lipid Bilayers And Forming Nanodiscs, Ghada Alramadan

Dissertations and Theses

Cell membranes, or plasma membranes, play an essential role in the structure and the function of living cells. In 1972, the fluid mosaic membrane model was the first unifying paradigm of membrane structure. It is no longer considered adequate because evidence of many non-homogeneous lipid structures in both natural and model membranes have been discovered over the past thirty years. The field of membrane biophysics now uses updated versions of the mosaic model, which consists of the complex mixture of different lipid species. The lipid species found in natural membranes produce a range of dynamic, laterally segregated, non-homogeneous domains, which …

Long-Term Variation Of Summer Phytoplankton Communities In An Urban Lake In Relation To Lake Management And Climate Conditions, Yuan Xiao Grund

Dissertations and Theses

Eutrophication is one of the primary factors causing harmful cyanobacteria blooms in freshwater lakes; climate change such as warmer temperature can potentially further increase both frequency and intensity of blooms. This study investigated the long-term changes in water quality and summer phytoplankton assemblages in Oswego Lake, OR, in relation to lake management practices (e.g., hypolimnetic aeration and alum treatments), as well as climatic and regional meteorological conditions. Both water quality and phytoplankton assemblages were sampled biweekly during summer seasons between 2001 and 2013. The concentrations of total phosphorus (TP), soluble reactive phosphorus (SRP) and total nitrogen (TN) decreased 66%, 93% …

From Probabilistic Socio-Economic Vulnerability To An Integrated Framework For Flash Flood Prediction, Sepideh Khajehei

Dissertations and Theses

Flash flood is among the most hazardous natural disasters, and it can cause severe damages to the environment and human life. Flash floods are mainly caused by intense rainfall and due to their rapid onset (within six hours of rainfall), very limited opportunity can be left for effective response. Understanding the socio-economic characteristics involving natural hazards potential, vulnerability, and resilience is necessary to address the damages to economy and casualties from extreme natural hazards. The vulnerability to flash floods is dependent on both biophysical and socio-economic factors. This study provides a comprehensive assessment of socio-economic vulnerability to flash flood alongside …

Accumulation And Transmission Dynamics Of A Naturally-Occurring Mtdna Deletion In Caenorhabditis Briggsae, Jennifer Anne Sullins

Dissertations and Theses

Maintaining mitochondrial genome sequence integrity is essential for preserving normal mitochondrial function. Several human diseases have been associated with heteroplasmic mitochondrial genome mutations, but few genetic systems can simultaneously represent pathogenic mitochondrial genome evolution and inheritance. The nematode Caenorhabditis briggsae is one such model. Natural C. briggsae isolates are globally-distributed and phylogenetically grouped into three distinct clades, with isolates exhibiting varying levels of a large-scale mtDNA deletion, nad5∆. Furthermore, a small subset of clade II isolates exhibits putative compensatory mutations that may reduce the risk of deletion formation and accumulation in those populations. In this thesis, the author characterizes the …

The Interplay Between Early Childhood Education And Mental Health: How Students In An In-Service Early Childhood Teacher Education Program Experience Children With Mental Health And Behavioral Challenges In The Classroom, Katie Statman-Weil

Dissertations and Theses

All early childhood educators who work with children between birth and six years of age are likely to encounter young children who experience behavioral and mental health challenges throughout their careers. Research demonstrates that educators can play a vital role in children's mental health and behavioral development. However, often early childhood educators do not believe they have the knowledge or tools to accurately identify and successfully handle the unique challenges that arise when working with children with behavioral and mental health issues.

Using an Anti-Oppressive Framework, this research study explores, through a qualitative case study design, how students in an …

Characterizing Temperature Variability States Across Southern South America And Associated Synoptic-Scale Meteorological Patterns, Judah Adam Detzer

Dissertations and Theses

The aim of this thesis is to understand spatiotemporal temperature variability in southern South America by identifying overarching temperature variability states and their associated synoptic-scale meteorological patterns. Further, the temporal frequency of occurrence of those temperature variability states is investigated as is the role of recurrent low-frequency modes of climate variability (El Niño Southern Oscillation and the Southern Annular Mode) on temperature variability. K-means cluster analysis is used to group all months during the period 1980-2015 into four primary categories for summer and winter separately. Monthly maps of temperature anomalies are provided as input to the k-means algorithm and the …

Lone Wolves And Copycats: Assessing Policy And Infrastructure For Flood Hazard And Floodplain Management, Samantha L. Hamlin

Dissertations and Theses

To mitigate flood hazard, which affects millions of people every year, increasing numbers of communities are developing green infrastructure policies to not only mitigate the hazard, but to meet other community policy objectives, as green infrastructure is often cited for the multiple benefits it confers. To support the implementation of policies that help communities meet their policy objectives, however, it is imperative to understand how policy is innovated and adopted. To do so, I applied the internal determinants and regional diffusion models, what I refer to as the lone wolf and copycat models. In policy, a lone wolf innovates a …

Representations Of Immigrants In Young Adult Literature, Frances Augusta Ramos Verbruggen

Dissertations and Theses

This study was conducted to determine how immigrants and the immigration experience are represented in current young adult (YA) literature. In the study, I asked the following questions: Who are the immigrant characters in recent YA books? Why do they come? How do they experience immigration? How are they perceived or treated by others? A content analysis methodology was used to examine, from a critical literacy viewpoint, recent young adult novels with immigration themes. Data were analyzed by identifying and interpreting patterns in themes across 22 YA novels with immigrant protagonists or other important characters, published between 2013 and 2017. …

Thermally (Un-) Stratified Wind Plants: Stochastic And Data-Driven Reduced Order Descriptions/Modeling, Naseem Kamil Ali

Dissertations and Theses

Wind energy is one of the significant sources of renewable energy, yet a number of challenges preclude optimal operation of wind plants. Research is warranted in order to minimize the power losses and improve the productivity of wind plants. Here, a framework combining turbulence theory and data mining techniques is built to elucidate physics and mechanisms driving the energy extraction of the wind plants under a number of atmospheric/operating conditions. The performance of wind turbines is subjected to adverse effects caused by wake interactions. Therefore, it is crucial to understand wake-to-wake interactions as well as wake-to-atmospheric boundary layer interactions. Experimental …

Age-Based Differences In The Usefulness Of Resources: A Multi-Study Investigation Of Work And Well-Being Outcomes, Lale Muazzez Yaldiz

Dissertations and Theses

The labor force is aging globally. It is projected that the number of older workers will increase in the workforce in the near future. At the same time, it is estimated that workplaces will grow more age-diverse, where younger and older workers will work side-by-side more often than they used to. These demographic shifts in the workforce necessitate a further understanding of the differences between the values, needs and motivation, and work outcomes of employees of different ages. To this end, few studies to date have investigated whether job-related resources are differentially useful for the work and non-work outcomes of …

A Case Study Of Student And Staff Perceptions Of The School Breakfast Program: Food For Thought From A College Preparatory High School For Underserved Students, Jennifer Lucas Young

Dissertations and Theses

Research suggests that participation in the School Breakfast Program positively impacts academic success by improving student behavior, cognitive functioning, and attendance. Additionally, the School Breakfast Program appears to improve food insecurity, overall health and weight-related issues. However, compared to the National School Lunch Program, participation in the School Breakfast Program has been historically low, especially at the high school level. Using an integrated composite framework, a combination of social cognitive theory and ecological systems theory, as the conceptual model, this qualitative case study explored factors influencing student breakfast eating and participation in the school's breakfast program within a college-preparatory high …

The Role Of The Academic Analyst In Shared Governance, Rebecca Ann Mathern

Dissertations and Theses

This research explores the roles of academic professionals in higher education, specific to how they engage in decision-making processes. Academic professionals provide important functions in higher education work but there is little in the literature about these actors and their contributions to leadership and governance. A literature review triangulated role theory, organization theory, and the shared-governance field of study to bring together actors within higher education and compare their involvement based on the shared-governance model in operation at different institutions. The researcher introduced the hypothesis that when registrars are not involved in curriculum management, there may be negative effects on …

Investigating Time During Residential Program Until Transition For Adjudicated Youth: A Mixed Methods Study Using Event History Analysis With Follow-Up Interviews, Emily Carol Lott

Dissertations and Theses

Residential placement is considered the most severe sanction for adjudicated youth, yet there is little consensus on best practices and interventions in residential settings. Demographic trends in the juvenile justice system further exacerbate challenges in studying residential placements. Disparities among minority youth, diverging state definitions of juvenile sex offenses, discrepancies in recidivism measures, and variations in local and state juvenile courts have contributed to a convoluted system that has struggled to identify the meaning of "success" in residential settings.

Building on theories of engagement in residential care and program theory of change, this mixed methods study explores how various components …

Early Detection Of Corrosion Via Hydrogel-Based Spectroelectrochemical Sensors, Capri Ann Price

Dissertations and Theses

The backbone of the industrialized world is comprised of refined, zerovalent metal, a material which thermodynamically favors an oxidative return to more chemically stable states. There are many methods used to slow or delay this process, such as protective coatings, sacrificial anodes, and alloys, but no method can entirely prevent corrosion. This body of work instead proposes detecting the earliest chemical markers of corrosion: that is, metal ions as they solubilize from a metal surface. Such information would allow maintenance personnel to make informed decisions about the necessity or lack thereof of preventive maintenance, and intervene before advanced damage has …

Shear-Force Acoustic Near-Field Microscopy And Its Implementation In The Study Of Confined Mesoscopic Fluids, Theodore Alex Brockman

Dissertations and Theses

The recently developed Shear-Force Acoustic Near-Field Microscope (SANM) is used to investigate the viscoelastic properties of a mesoscopic fluid layer confined between two trapping boundaries, one being a stationary substrate and the other the apex of a laterally oscillating tapered probe. Hardware improvements and evaluation of the SANM-probe robustness will be a major focus of this thesis. The investigation first discusses characterization and recent developments made to the microscope, including: modifications to the sensor head, conditioning of the Nano positioners electrical drive signal, and the assessment of the probe against eventual plastic deformation or compliance against interactions with samples (the …

Carbon-Supported Transition Metal Nanoparticles For Catalytic And Electromagnetic Applications, Kavita Meduri

Dissertations and Theses

Recently, there has been growing interest in using transition metals (TM) for catalytic and electromagnetic applications, due to the ability of TMs to form stable compounds in multiple oxidation states. In this research, the focus has been on the synthesis and characterization of carbon-supported TM nanoparticles (NPs), specifically palladium (Pd) and gold (Au) NPs, for catalytic applications, and transition metal oxides (TMO) NPs, specifically Fe₃O₄ NPs for electromagnetic applications. Carbon supports have several advantages, such as enabling even distribution of particles, offering large specific surface area with excellent electron conductivity, and relative chemical inertness.

In this dissertation, …

Studying The Effects Of Motivated Reasoning On Appraisals Of Message Strength, Aric Christopher Powell

Dissertations and Theses

This study was designed to investigate decision-making as it relates to message appraisal, and determine what effect, if any, identification with the message source has on those appraisals. For the purpose of study, message appraisal was operationalized as message strength ratings. Furthermore, the study investigated how the political ideology of message receivers and the perceived partisanship of message senders might influence identification, and message appraisal by extension. The study used the theory of motivated reasoning to explain the role of identification in the process of message appraisal. The results indicate that there is a relationship between identification and message strength …

Judgments Of Lethal Risk: A Comparison Of Visual And Narrative Stimuli, Derek Anthony Bonniksen

Dissertations and Theses

The nature of how we make judgments has received a great deal of attention in the last few decades. Risk communication research has indicated that risk-related messages can elicit affective responses in audiences, which can then have a significant impact on how such audiences judge risk in general. Using a 2 x 2 between-subjects factorial design, this study found that, contrary to Johnson and Tversky's (1983) findings, presenting narratives about lethal risk does not influence readers' judgments about the frequency that risks occur, nor do such narratives influence participant worry levels about the lethal risks, more generally. Additionally, the inclusion …

Annotation-Enabled Interpretation And Analysis Of Time-Series Data, Niveditha Venugopal

Dissertations and Theses

As we continue to produce large amounts of time-series data, the need for data analysis is growing rapidly to help gain insights from this data. These insights form the foundation of data-driven decisions in various aspects of life. Data annotations are information about the data such as comments, errors and provenance, which provide context to the underlying data and aid in meaningful data analysis in domains such as scientific research, genomics and ECG analysis. Storing such annotations in the database along with the data makes them available to help with analysis of the data. In this thesis, I propose a …

Ensemble Data Assimilation For Flood Forecasting In Operational Settings: From Noah-Mp To Wrf-Hydro And The National Water Model, Mahkameh Zarekarizi

Dissertations and Theses

The National Water Center (NWC) started using the National Water Model (NWM) in 2016. The NWM delivers state-of-the-science hydrologic forecasts in the nation. The NWM aims at operationally forecasting streamflow in more than 2,000,000 river reaches while currently river forecasts are issued for 4,000. The NWM is a specific configuration of the community WRF-Hydro Land Surface Model (LSM) which has recently been introduced to the hydrologic community. The WRF-Hydro model, itself, uses another newly-developed LSM called Noah-MP as the core hydrologic model. In WRF-Hydro, Noah-MP results (such as soil moisture and runoff) are passed to routing modules. Riverine water level …

Measuring And Modeling Evolution Of Cryoconite Holes In The Mcmurdo Dry Valleys, Antarctica, Felix Jacob Zamora

Dissertations and Theses

Cryoconite holes are vertical columns of meltwater within the shallow subsurface of glaciers. In the McMurdo Dry Valleys (MDV) of Antarctica cryoconite holes are a source of meltwater and harbor microbial communities in an otherwise arid environment with low biologic activity. The holes form as sediments on the ice surface, which are darker than the surrounding ice, are preferentially heated by solar radiation. The warm sediments melt the underlying ice and migrate downwards. An ice lid forms, isolating them from the below-freezing atmosphere enabling them to remain thawed. In this study, field observations, laboratory experiments, and numerical modeling are used …

Ozone-Surface Exchange And Transport And Transformation Near Ventilation Air Supply, Pradeep Ramasubramanian

Dissertations and Theses

Ozone in indoor environments can pose a health risk to human occupants; around half of exposure to this pollutant occurs inside buildings. One approach to reducing indoor O₃ levels is to mitigate O₃ as it enters a building via outdoor air ventilation supply. Often, mechanical systems that introduce outdoor air into buildings are placed on building rooftops. At the urban scale, greenery has been shown to reduce levels of some harmful pollutants, including ozone and cities like Portland, OR, are mandating green roofs be built on large commercial buildings to increase urban green surfaces. We investigate if rooftop …