Digital Commons Network^™

On The Feasibility Of Ultrasonic Full Waveform Evaluation With Changing Testing Conditions For The Quality Control Of Manufacturing Parts, Simon Schmid, Thomas Schumacher, Christian U. Grosse

Civil and Environmental Engineering Faculty Publications and Presentations

Fast volumetric non-destructive testing methods are needed, especially for quality control in manufacturing lines. Ultrasonic testing with full waveform evaluation is a promising method for this. However, changes in coupling conditions or environmental factors can significantly alter the ultrasound signal, sometimes more than actual defects. This study investigates the effect of various factors on the ultrasound signal based on a Monte Carlo study with wavefield simulations. The test specimens comprise aluminium plates with holes of varying sizes and positions. Using both experimental as well as simulated data, the performance of two commonly used comparison metrics, namely the R2 score and …

Implementation Of A Realistic Artificial Data Generator For Crash Data Generation, Lauren Hoover, Md. Istiak Jahan, Tanmoy Bhowmik, Sudipta Dey Tirtha, Karthik C. Konduri, John Ivan, Kai Wang, Shanshan Zhao, Joshua Auld, Naveen Eluru

Civil and Environmental Engineering Faculty Publications and Presentations

In this paper, a framework is outlined to generate realistic artificial data (RAD) as a tool for comparing different models developed for safety analysis. The primary focus of transportation safety analysis is on identifying and quantifying the influence of factors contributing to traffic crash occurrence and its consequences. The current framework of comparing model structures using only observed data has limitations. With observed data, it is not possible to know how well the models mimic the true relationship between the dependent and independent variables. Further, real datasets do not allow researchers to evaluate the model performance for different levels of …

Faculty Senate Monthly Packet April 2024, Portland State University Faculty Senate

Faculty Senate Monthly Packets

The April 1, 2024 monthly packet includes the April agenda, appendices, and the Faculty Senate minutes and attachments from the meeting held April 1, 2024.

Bridging Barriers To Digital Accessibility: An Opportunity For Technical Editors, Julian Luck

Book Publishing Final Research Papers

Digital content is overwhelmingly inaccessible across the web, and web accessibility is a particularly wicked problem. Technical editors with accessibility specializations serve as a part of the solution, however, the market for these professionals is emerging and poorly understood. The purpose of this research is to explore this emerging market and determine the strengths, weaknesses, opportunities, and threats for these editors. Considering the limited body of knowledge surrounding this market, I utilize a variety of diverse web resources including peerreviewed journal publications, blogs, forums, and trusted web accessibility resources and organizations. The findings, contextualized by my identity as a disabled …

First-Principles Calculations Of Lattice Thermal Conductivity In Tl,3Vse4: Uncertainties From Different Approaches Of Force Constants, Zhi Li, Yi Xia, Chris Wolverton

Mechanical and Materials Engineering Faculty Publications and Presentations

Accurate and reliable first-principles simulations of lattice thermal conductivity (κL) of highly anharmonic crystals have long been challenging in condensed matter and materials physics. With recent theoretical advances, the calculation of κL has evolved into a sophisticated process requiring the consideration of higher levels of refinements, such as high-order phonon-phonon scattering, anharmonic phonon renormalization, and heat transport beyond the phonon gas picture. Interatomic force constants (IFCs), however, as a shared pillar of the above concepts, are sometimes ambiguously implemented in this process, resulting in non-negligible uncertainties among different studies. Here, we revisit the ultralow κL of Tl3VSe4 and make a …

An Introduction To Nanomaterials For Nanopackaging, James E. Morris

Electrical and Computer Engineering Faculty Publications and Presentations

The multiple purposes of an electronics “package” include the provision of mechanical support to the silicon chip, for example, and protection from the environment, the delivery of power in and the facilitation of heat out, and the reliable input and output of information signals, whether electrical or optical. In the age of heterogeneous integration, this includes the internal conversion of signal modes between multiple technologies within the package, while maintaining the traditional requirement of reliable information transmission between packages, e.g., on a traditional circuit board. This article presents some selected examples of nanopackaging, i.e., the application of nanotechnologies, (nanoparticles, carbon …

The Complexities Of Irrigation Efficiency: Groundwater Data, Agro-Hydrology, And Water Decision-Making In Central Oregon, Rebecca Anderson, Alida Cantor

Geography Faculty Publications and Presentations

Irrigation efficiency projects aim to conserve water for in-stream flow and agricultural use by reducing water losses throughout the system. Piping irrigation canals is a common irrigation efficiency method that results in trade-offs: while it increases efficiency of irrigation water conveyance, it reduces incidental groundwater recharge. This paper focuses on the data and decision-making of canal piping, focusing primarily on understanding the potential impacts of reduced canal leakage on shallow wells. By conducting a spatial analysis of shallow wells in the basin at risk of being impacted by canal piping, and combining this with interviews with water managers in central …

Modeling Injury Severity Of Truck-Involved Crashes Under Covid-19 Regulatory Changes, William Mckenzie

Civil and Environmental Engineering Master's Project Reports

At the start of the pandemic the Federal Motor Carrier Safety Administration issued declaration No. 2020-002 which included a long list of goods given temporary emergency relief (deregulation) from national statutes 49 CFR Parts 390-399 of the Federal Motor Carrier Safety Regulations that oversee trucking. In particular, this granted emergency relief from Title 49 CFR § 395.3: maximum driving time for motor carriers or their drivers, regarded as hours-of-service (HOS), and subsequently further expanded to include short-haul trips, adverse driving conditions, break requirements, and sleeper berths. Regulations which play a crucial role in establishing the safe operation and management of …

A Memoir Of My Reading, Bennett B. Gilbert

History Faculty Publications and Presentations

Surveying nearly seven decades of habitual and obsessive reading, I consider how my character and psychology used reading to shape philosophical questions that move me into forms in which I could pursue them by reading. This became both the method and the substance of my philosophical work. It preserved some core emotional issues but also gave me the way to integrate them into scholarship and into my life.

Beavers, Hydrology, And Wapato: A Baseline For Monitoring Franz Lake National Wildlife Refuge, Justine Casebolt

Environmental Science and Management Professional Master's Project Reports

Located in the lower Columbia River floodplain, Franz Lake National Wildlife Refuge is a unique landscape with a complex land use history. For thousands of years, Indigenous tribes lived on this land. In the early 1990s, U.S. Fish and Wildlife Service acquired the land, after it was identified as a mitigation site following the construction of the Bonneville Lock and Dam. Franz Lake Refuge was once known for its prevalent Wapato (Sagittaria latifolia) population, an emergent plant with edible tubers and an important food source for Indigenous people. With specific growth requirements and hydrologic conditions for germination and …

Accommodating Spatio-Temporal Dependency In Airline Demand Modeling, Sudipta Dey Tirtha, Tanmoy Bhowmik, Naveen Eluru

Civil and Environmental Engineering Faculty Publications and Presentations

The objective of the current study is to examine monthly air passenger departures at the airport level considering spatial interactions between airports. In this study, we develop a novel spatial grouped generalized ordered probit (SGGOP) model system of monthly air passenger departures at the airport level. Specifically, we estimate two variants of spatial models including spatial lag model and spatial error model. In the presence of repeated demand measures for the airports, we also consider temporal variations of spatial correlation effects among proximally located airports by employing space and time-based weight matrix. The proposed model is estimated using monthly air …

Fluorescence Microscopy With Deep Uv, Near Uv, And Visible Excitation For In Situ Detection Of Microorganisms, Noel Case, Nikki Johnston, Jay Nadeau

Physics Faculty Publications and Presentations

We report a simple, inexpensive design of a fluorescence microscope with light-emitting diode (LED) excitation for detection of labeled and unlabeled microorganisms in mineral substrates. The use of deep UV (DUV) excitation with visible emission requires no specialized optics or slides and can be implemented easily and inexpensively using an oblique illumination geometry. DUV excitation (<280 >nm) is preferable to near UV (365 nm) for avoidance of mineral autofluorescence. When excited with DUV, unpigmented bacteria show two emission peaks: one in the near UV ∼320 nm, corresponding to proteins, and another peak in the blue to green range, corresponding to …

Inertial Particle Clustering Due To Turbulence In An Air Jet, Bianca Viggiano, Kris Gish, Stephen Solovitz, Raul Bayoan Cal

Mechanical and Materials Engineering Faculty Publications and Presentations

Explosive volcanic eruptions create turbulent plumes of fine ash particles. When these particles collide in the presence of moisture and electrostatic fields they combine into larger aggregates, which can significantly change the atmospheric residence time of the airborne cloud. Previous studies have suggested that turbulence may lead to preferential concentration—also known as clustering—of particles within the flow, increasing the likelihood of collisions and aggregation. Few experimental studies have quantified these processes for volcanic plumes. This behavior was investigated using a particle-laden air jet. By systematically varying the exit speed and the size, density, and concentration of particles, flows were produced …

Comparison Of Emissions Across Tobacco Products: A Slippery Slope In Tobacco Control, Ahmad El-Hellani, Ayomipo Adeniji, Hanno C. Erythropel, Thomas Lamb, Qixin Wang, Vladimir Mikheev, Robert Strongin, Multiple Additional Authors

Chemistry Faculty Publications and Presentations

In this narrative review, we highlight the challenges of comparing emissions from different tobacco products under controlled laboratory settings (using smoking/ vaping machines). We focus on tobacco products that generate inhalable smoke or aerosol, such as cigarettes, cigars, hookah, electronic cigarettes, and heated tobacco products. We discuss challenges associated with sample generation including variability of smoking/vaping machines, lack of standardized adaptors that connect smoking/vaping machines to different tobacco products, puffing protocols that are not representative of actual use, and sample generation session length (minutes or number of puffs) that depends on product characteristics. We also discuss the challenges of physically …

On Fire And Water: The Intersection Of Wetlands And Burning Strategies In Managing The Anthropogenic Plant Communities Of Yosemite National Park, Douglas Deur, Rochelle Bloom

Anthropology Faculty Publications and Presentations

The existing literature confirms that Native American tribes historically enhanced culturally preferred plant communities through periodic burning in what is today Yosemite National Park; in turn, beginning with nineteenth-century park development, fire suppression contributed to conifer and shrub encroachment on anthropogenic meadows and other culturally significant habitats. However, we contend that traditional burning practices cannot be understood without considering the pronounced cultural role of wetland habitats and species, and the intersection between burning practices and wetland plant communities among tribes of the Sierra Nevada Range. Our ethnographic investigations revealed that a majority of culturally important plants identified by tribal members …

Dynamic Fibrillar Assembly Of Αb-Crystallin Induced By Perturbation Of The Conserved Nt-Ixi Motif Resolved By Cryo-Em, Russell Mcfarland, Steve Reichow

Chemistry Faculty Publications and Presentations

αB-crystallin is an archetypical member of the small heat-shock proteins (sHSPs) vital for cellular proteostasis and mitigating protein misfolding diseases. Gaining insights into the principles defining their molecular organization and chaperone function have been hindered by intrinsic dynamic properties and limited high-resolution structural analysis. To disentangle the mechanistic underpinnings of these dynamical properties, we mutated a conserved IXI-motif located within the N-terminal (NT) domain of human αB-crystallin. This resulted in a profound structural transformation, from highly polydispersed caged-like native assemblies into a comparatively well-ordered helical fibril state amenable to high-resolution cryo-EM analysis. The reversible nature of the induced fibrils facilitated …

Spectroscopic End Point Detection With An Electron Beam Evaporator, Ryan Mcgraw

University Honors Theses

Spectroscopic end point detection is a common tool used for measuring slope changes in wavelength intensity. Using algorithms able to apply this concept, coatings will be able to be dynamically measured in real time and stopped at the appropriate level to ensure process uniformity. It is currently applied to reductive processes such as etching, where the surface will start to be eaten away, creating a plasma. When the entire amount of a material on a substrate has been eaten away, the plasma will change color as it is beginning to etch a different material. Using a spectrometer, this point where …

Intersectionalities Of Systematic Barriers Set Upon Underrepresented Students In Stem: Capturing The Potential Benefits Of Online Modality, Raiyasha Aiyanna Paris

University Honors Theses

The prevalence of racism and microaggressions in STEM disciplines within colleges presents significant hurdles to the academic success and well-being of underrepresented students. Microaggressions, encompassing subtle biases and stereotyping, have a cumulative impact, inducing heightened stress, diminished motivation, and reduced self-efficacy among minority students, thereby impeding cognitive functioning and hindering academic progress (Ogunyemi et al., 2020). The existence of these negative emotional responses creates a less conducive learning environment for academic achievement. Additionally, structural inequalities within STEM institutions contribute to disparities in resource access, limited mentorship opportunities, and support networks crucial for success in STEM fields (Atkins et al., 2020). …

Floodplain Restoration And Its Effects On Summer Water Temperature And Macroinvertebrates In Whychus Creek, Oregon (Usa), Wesley N. Noone, Patrick M. Edwards, Yangdong Pan, Colin R. Thorne

Environmental Science and Management Faculty Publications and Presentations

Stream restoration is a proposed climate adaptation tool; however, outcomes of floodplain restoration on stream temperature have been debated. Despite a growing number of studies that investigated water temperature in restored streams, few have quantified temperature variations in new habitat types created by restored hydrogeomorphic processes to explore the effects on aquatic macroinvertebrates. We evaluated the hypotheses: (1) restoration increases habitat diversity, (2) habitat diversity increases water temperature variability, and (3) restoration increases the diversity of macroinvertebrate assemblage and temperature associations. In August 2021, we collected environmental data to describe the aquatic habitats, water temperature and quality (continuous and discrete), …

Numerical Study Of Cone Penetration In Calcareous Sands: Investigating Cone Tip Resistance Correction Factors For Crushable Soils, Stephanie Michelle Hyder

Dissertations and Theses

The cone penetration test (CPT) is used to characterize the behavior and properties of soils, including the susceptibility to earthquake liquefaction triggering. The cone tip resistance relates to liquefaction susceptibility through relative density, where relative density is closely related to both cone tip resistance and liquefaction susceptibility. Currently, published methods of estimating liquefaction potential (i.e., cyclic resistance ratio) are based on silica sands and do not properly characterize calcareous sands. The measured cone tip resistance in calcareous sands is lower than in silica sands at the same relative density; this difference is generally attributed to the higher compressibility of calcareous …

Norse Inspired Tales: Four Changes Of Fate, Pete Wille

University Honors Theses

Norse Inspired Tales: Four Changes of Fate is a collection of four original short stories meant to act as an introduction to a broader literary world where Norse myth meets late eighteen hundred's, San Francisco. The introduction gives background on my literary journey and explains some of the choices made within these stories. Each following story reveals the characters and the world they currently inhabit.

Webinar: Assessing Cool Corridor Heat Resilience Strategies For Human-Scale Transportation, Ladd Keith, Kristina Currans

TREC Webinar Series

Heat is the number one weather-related killer in the United States, and the implications of heat impacts range from individual transportation users, to emergency management services, and entire transportation networks and systems. In this presentation, we'll cover key concepts for urban planning and heat resilience, including heat mitigation and management strategies. Additionally, we will discuss the original NITC-sponsored data collection evaluating one such cool corridor strategy--PlusTI cool pavement rejuvenator--and the associated challenges of researching impacts of strategies on human-comfort in natural and built environments.

Corporatizing Violence: Targeted Repression Of Indigenous Dissent In Democratic States, Laikaika Layne Rivera

Dissertations and Theses

This thesis explores state repression of disruptive protests against private development projects in democracies. Using a mixed methods approach, including logistic regression and case studies, the research identifies key factors influencing repression. Indigenous leadership, fragmented public opposition, and private elite influence increase the likelihood of violent repression. The findings suggest that when public resistance is insufficient against powerful private interests, coercive institutions resort to violent strategies to quell disruptions and signal increased costs for future dissent. State repression is more likely when the protest movement is comprised of Indigenous groups than compared to those of the general public. The study …

Faculty Mentors' Influence On Latino/A/X Stem Undergraduates' Stem Identity Development, Sandy Cerda-Lezama

Dissertations and Theses

Despite Latino/a/x college student attendance rising substantially over the past decades, their graduation rates do not match the increased admission rates. In addition, Latino/a/x students are considerably under-represented in STEM. However, research suggests that when these students are encouraged by social partners to have meaningful participation and given resources such as mentoring, this eases the barriers they experience. The current study utilized interviews with 11 Latino/a/x STEM undergraduates (aged 18-29) to understand how faculty mentors influence their STEM identity development. Students shared answers about how faculty promoted and inhibited their STEM identity development through conversations about their sense of competence, …

A Survey Of North American Electric Bicycle Owners, Cameron Steven Bennett

Dissertations and Theses

Rapid recent growth in the popularity of electric bicycles (e-bikes) has captured the attention of transportation researchers and policymakers seeking safe, sustainable, and active alternatives to conventional transportation modes. This thesis presents an investigation of e-bike owners in North America, complementing previous efforts in 2013 and 2017, and suggests implications for North American transportation planning.

An online survey was distributed to e-bike owners in the United States and Canada through email outreach, purchase incentive programs, and social media. The survey included questions on the respondents’ demographics, e-bikes, purchase decisions, travel behavior, perceptions of e-bikes, crash experience, maintenance needs, and receipt …

Comparison Of Conventional And Adaptive Acoustic Beamforming Algorithms Using A Tetrahedral Microphone Array In Noisy Environments, Megan Brittany Ewers

Dissertations and Theses

In situ acoustic measurements are often plagued by interfering sound sources that occur within the measurement environment. Both adaptive and conventional beamforming algorithms, when applied to the outputs of a microphone array arranged in a tetrahedral geometry, are able to capture sound sources in desired directions and reject sound from unwanted directions. Adaptive algorithms may be able to measure a desired sound source with greater spatial precision, but require more calculations and, therefore, computational power. A conventional frequency-domain phase-shift algorithm and a modified adaptive frequency-domain Minimum Variance Distortionless Response (MVDR) algorithm were applied to simulated and recorded signals from a …

Tryon Creek Culvert Replacement: Bringing Salmon Back, Amy Chomowicz

Urban Ecosystem Research Consortium of Portland/Vancouver

The overarching goal of the Tryon Creek Culvert Replacement Project is simple: to restore native and wild salmonids and lamprey in the lower Willamette River. The existing Tryon Creek Highway 43 culvert is one-quarter mile upstream from the confluence of Tryon Creek and the Willamette River, and it bars access to vital spawning, rearing, and migratory habitat for all salmon, steelhead, and Pacific Lamprey using the Willamette. The City of Portland and project partner, the United States Army Corps of Engineers, will construct a new, much wider, open bottom culvert that will allow the stream to flow more naturally. The …

Why Is The Oaks Bottom Reservoir So Dead And Brown? A Success Story Of Purple Loosestrife Control, Laura Guderyahn

Urban Ecosystem Research Consortium of Portland/Vancouver

Ever since the early 1990’s, when a water control structure was used to flood the 60acre ponded wetland at Oaks Bottom to increase waterfowl overwintering habitat, Purple Loosestrife (Lythrum salicaria) has thrived. Starting in 2008, Portland Parks and Recreation (PPR) and the Bureau of Environmental Services (BES) partnered with the Oregon Department of Agriculture (ODA) to annually release thousands of three different species of biocontrol beetles throughout the wetland. However, the unnatural flooding regime due to the water control structure and a greatly undersized culvert connecting the refuge to the Willamette River, resulted in annual reproductive and overwintering …

Proceedings Of The 22nd Annual Urban Ecology & Conservation Symposium (2024), Lori Hennings

Urban Ecosystem Research Consortium of Portland/Vancouver

These proceedings document the agenda and abstracts for presentations and posters from the 22nd annual conference (2024) organized by the Urban Ecosystem Research Consortium of Portland/Vancouver (UERC). The UERC is a consortium of people from various universities and colleges, state and federal agencies, local governments, non-profit organizations and independent professionals interested in supporting urban ecosystem research and creating an information-sharing network of people that collect and use ecological data in the Portland/Vancouver area. The annual conference has an open call for abstracts. The UERC organizing committee selects the final oral and poster presentations, along with 2 invited keynote presentations

Teaching In A Kenyan Refugee Camp: A Critical Ethnography Of The Impact Of Teacher Preparation And Cultural Experience On Pedagogy, James Adiok Mayik

Dissertations and Theses

This research involved an investigation of the classroom experiences of formally unprepared refugee teachers in Kakuma Refugee camp. The purpose was to understand how refugee teachers with no preservice preparation in accordance with the standards of Kenya Teacher Service Commission (TSC) perceive and interact with pedagogical content knowledge (PCK) and cultural relevancy in their daily classroom experiences with students in a refugee camp-based school in Kenya. What informed this study was the view that refugee teachers bring with them their respective and diverse cultural knowledge--ontology, epistemology, and axiology. To gain better understanding of the experiences and perspectives of these educators, …