Digital Commons Network^™

Assessment Of High-Performance Steels Through Additive Manufacturing And Ultrasonic Impact Peening, Md Touhidul Islam Rimon

Theses and Dissertations

This abstract focuses on the treatment of three distinct materials: 17-4 PH stainless steel, a nickelbased super alloy, and AISI 4140 stainless steel. The treatment process involves a combination of laser deposition and ultrasonic impact peening.

The study explores the effects of this treatment on the mechanical and microstructural properties of the mentioned materials. Laser deposition is utilized to enhance surface characteristics, such as hardness, wear resistance, and corrosion resistance. Nickel-based super alloys are known for their exceptional high-temperature strength and corrosion resistance, making them suitable for demanding applications in aerospace and power generation industries. AISI 4140 stainless steel is …

Applying Systems Engineering Principles To The Design Of Multi-Channel Functional Electrical Stimulator, Yasser Ayeva

Theses and Dissertations

Paralyzed patients due to spinal cord injuries or other injuries can produce functional movements with the help of functional electrical stimulation (FES). Electrical discharges are applied to the patient's muscles to help with specific movements like walking, standing, and holding and grasping objects (Cleveland Clinic,2023). FES is not a novel technology, in fact, the term FES was not used until 1967 when Moe and Post created it. (Moe & Post, 1962). This technology has been around, and a wide range of devices utilizing it are currently on the market to support patients' treatment and rehabilitation all over the world. As …

Black Lives Matter: Protesting As A Form Of Communication, Tiffany Tara Sonterre

Theses and Dissertations

On May 25, 2020 in Minneapolis, Minnesota, Officer Derek Chauvin knelt on the neck of George Floyd for 9 minutes and 29 seconds, resulting in Floyd’s death; protests and riots broke out not only in Minnesota, but around the United States (Taylor, 2021). This was just the most recent event in the repeated police brutality against people of color. This dissertation is a case study examining protesting as a form of communication in regards to the Black Lives Matter movement. The deaths of 15 Black people which generated notable media attention are examined via a variety of news sources, starting …

Vehicle Crashes In Minnesota: Spatial And Temporal Patterns And Contributing Factors To Crash Severity, Bastien Koralalage Pavithra Navodi Rodrigo

Theses and Dissertations

Vehicle crashes represent a critical global issue, resulting in numerous fatalities, injuries, and significant economic and societal impacts. In response, government officials worldwide are developing strategies and policies to enhance road safety and promote sustainable transportation systems, aiming for zero fatalities and injuries. Understanding the causes of crashes is essential for these efforts. This study focuses on identifying spatial and temporal patterns and contributing factors for the crash severity of vehicle crashes in Minnesota. Spatial distribution of crash hotspots is identified and visualized using spatial autocorrelation (global Moran I), hotspot analysis (Getis–Ord Gi*), and kernel density estimation in ArcGIS Pro. …

Restoring The Occupational Therapy Spirit In Hand Therapy Practice, Karrianna Iseminger

Theses and Dissertations

The dominant role psychosocial factors play in physical healing and disability perceptions of individuals with upper extremity (UE) conditions has been documented repeatedly in the literature for over 40 years. This population is at particular risk given the number of occupations requiring the functional use of one or both UEs for successful performance. However, occupational therapy practitioners (OTPs) specializing in hand therapy do not appear to have a shared practice or understanding of evaluation and intervention for psychosocial factors as they tend to focus mostly on the physical limitations of occupational performance. Therefore, the purpose of this three-article dissertation project …

Preparing Teachers To Differentiate Instruction: A Systematic Review, Betsy Ahearn

Theses and Dissertations

Differentiated Instruction is the term used to describe a variety of strategies for successfully addressing student diversity in the classroom. It relies on the attitudes of teachers who aim to maximize learning for all students and is based on the use of assessment data to respond to student readiness, interest, and learning profile. Although implementation has been found to have positive results in improving student performance many barriers have stood in the way of teachers utilizing these techniques. This systematic review of literature provides an extensive overview of information related to differentiated instruction guided by research questions. The methods utilized …

The Effects Of Disconfirming Feedback On Multiple Tests Of A Witness's Memory, Kaden Alan Bollinger

Theses and Dissertations

Testing a witness’s memory more than once has been shown to decrease accuracy in subsequent tests, and providing a witness with disconfirming feedback has also been shown to reduce confidence levels and reduce accuracy after they have made a decision from a lineup. The current study aims to examine how disconfirming feedback affects a witness’s accuracy throughout multiple lineups, as well as looking to examine the reflector variables of reaction time and the “Remember, Know, Guess” (e.g. RKG) questionnaire. Participants who incorrectly chose a suspect from an initial target-absent lineup were given disconfirming feedback and randomly assigned to either a …

Advancing Bridge Hydraulic Assessment With Hec-Ras 2d And Bathymetry Modeling In Arcgis Pro Using Hycat Asv Data, Daniel Iancu

Theses and Dissertations

This research centers on verifying an accurate and reliable method in deriving river bathymetry near bridge sites, which leads to critical enhancement of bridge scour analysis. The structural integrity of bridges is paramount, and accurate scour analysis is a cornerstone in civil engineering and public safety. Existing methods, though reliable and very well cemented in practice, may be improved with more precise water velocity estimates, which is essential for thorough bridge scour evaluations. Bridge assessments utilize bathymetry measurements in significant spots and or map out the continuous surface at the bottom of the river. This study seeks to validate if …

Nir-Spectroscopy With Data-Driven Application For Inspection And Prediction Of Combined Fouling And Moisture Contamination In Railroad Ballast., Eberechi Orie Ichi

Theses and Dissertations

Ballast contamination is a significant and growing challenge that causes railway track deterioration, poor drainage functionality, and early failure of railroad components. Traditional, human, destructive, field sampling, and most nondestructive evaluation (NDE) inspection methods are ineffective. They are plagued by drawbacks, such as inefficiency, subjective inspection outcome, alteration of existing structures, undermining the stability of the railroad substructure, traffic disruptions, and safety concerns, or providing limited information about the condition of the ballast. Therefore, a reliable noncontact technique is needed to evaluate, characterize, monitor, and predict the presence of contamination in railroad ballast. The conventional contamination indices only account for …

A Hybrid Framework To Secure Iot Sensor Networks Based On Blockchain And Machine Learning, Shereen Ismail

Theses and Dissertations

With the advances in sensor network technologies, more and more networked things, or smart objects, are being evolved in cyber-physical-based systems including Internet of Things. In recent years, Internet of Things Sensor Networks is a significant subject to a variety of internal and external cyber-attacks, necessitating the development of robust countermeasures tailored to their unique characteristics and limitations. Various prevention and detection techniques have been proposed to mitigate these attacks. Classical security techniques, such as spread spectrum, cryptography, and key management, may not efficiently detect attacks, and can demand sophisticated software and hardware changes, rendering these solutions insufficient to address …

Impacts Of Variations Of Temperature And Moisture Content In A Capping Feature On Thunderstorm Downdrafts, Andrew George Kramer

Theses and Dissertations

Thunderstorm downdrafts have been determined to be important factors in the near-surface dynamics of tornadogenesis. Tornadogenesis could be assisted by a downdraft and outflow that is cold enough to either tilt existing horizontal vortex lines or baroclinically generate vorticity at the surface. However, the downdraft should not be so cold that it would cut off the updraft of a thunderstorm with overly negatively buoyant air or by limiting the stretching of the updraft. The presence of a capping feature, or a layer of decreased lapse rate, can influence downdrafts by preventing transport of air from aloft, with associated properties, to …

Exploring Ambiguous Asteroid Taxonomic Classification, Tyler Linder

Theses and Dissertations

The Sloan Digital Sky Survey (SDSS) Moving Object Catalog (MOC) shows color variations between asteroid observations, which were observed multiple times. This is a surprising result that was not identified in the literature. Therefore, a data processing pipeline was built to extract the asteroid observations to analyze new data collected with the SMARTS 1.0m and 4m Blanco with DECam. The results appear to confirm the color variations on short timescales. However, there is still a long series of steps required before such a result can be proven, such as ensuring the level of photometric accuracy in the processing is smaller …

Examining The Shared Knowledge And Collaboration When Working With Students With Sensory Disabilities, Lacey Jo Long

Theses and Dissertations

The purpose of this study was to explore the shared knowledge and collaboration between special education and itinerant teachers working with students with sensory disabilities (i.e., teachers of students with visual impairments, teachers of the deaf/hard of hearing, and teachers of students who are deafblind). This study addressed the following research questions: What do special education and itinerant teachers need to know about sensory disabilities? How does this shared knowledge affect the collaboration of special education and itinerant teachers? The study was conducted using an anonymous online survey of special education and itinerant teachers serving students with sensory disabilities, including …

Lstm Application To Mobile Robotics For Stuck Detection, Wilson Lysford

Theses and Dissertations

This paper presents a solution for determining if a wheeled robot is stuck that is operating without high fidelity localization sensors or operating in a sensor denied environment. Expensive sensors are often left off of consumer grade robotics in order to make them more widely available to consumers. This leaves the robot without effective means of perception. Research has shown that LSTM neural networks can provide insight that would normally only be available to a robot fitted with expensive sensor packages such as RTK GPS or LIDAR systems. Specifically, IMU data paired with controller data and wheel odometry data. By …

Advances In Smoke Retrievals Using Lidar: Techniques And Applications, Natalie Midzak

Theses and Dissertations

Smoke aerosols arise from a variety of regional sources and fuel types dependent on the properties of the fire, leading to spatial variability in smoke composition and optical properties. After emission, these aerosols age and mix in the atmosphere with other aerosol species, such as sulfates, altering the optical and microphysical properties of the smoke aerosols over time. Further, smoke particles originating from biomass burning events are typically assumed to be spherical, yet non-spherical smoke particles are also reported from in situ observations. Thus, lidar ratio (extinction to backscatter ratio) and depolarization ratio exhibit spatiotemporal variability for smoke. In this …

Physical Wellness Of The Collegiate Athlete, Richard Michael Morgan

Theses and Dissertations

Wellness among athletes has been studied, but it is still unclear what dimensions make up wellness and where the clinician should focus their efforts. It is known that wellness is a multifaceted definition and has many dimensions. This dissertation will look at the dimension of physical wellness of an athlete pertaining to prevention, return to sport/rehabilitation, and enhancing performance. The purpose of the study is to understand how a clinician may have a direct effect on the physical wellness of the athlete through prevention, intervention or rehabilitation, and performance training. This paper will discuss three different sub-dimensions of physical wellness, …

Contributing Factors To Low Airspeed On Climbout Events As A Precursor To Loss Of Control Within The National General Aviation Flight Information Database, Owen Dae Poborsky

Theses and Dissertations

The nature of aviation is not without inherent risk. Conducting flight training operations increases the overall risks due to inexperience of the student pilot and the challenges of the learning environment. Flight data seeks to reduce these risks; as seen in its success for commercial airlines. These successes are slowly coming to general aviation through programs like the National General Aviation Flight Information Database (NGAFID). This study seeks to determine if the type of takeoff performed by the flight crew led to a lower indicated airspeed (IAS) during a low airspeed on climbout event. Using 262 individual low airspeed on …

Continuous Improvement In North Dakota Schools: Impact Of Mtss Essential Tier 1 Components In Red River Valley Education Cooperative Schools Identified For Targeted Or Comprehensive Support And Improvement, Amy Elizabeth Rohlk

Theses and Dissertations

The goal of the continuous improvement process in North Dakota K-12 education is to review and adjust practice to best support student learning. This study considered the continuous improvement services and supports provided by North Dakota Department of Public Instruction (NDDPI), such as providing training and support through regional education cooperatives, adopting the North Dakota multi-tier system of supports (NDMTSS), identifying criteria for low-performing schools under the targeted or comprehensive support and improvement (TSI or CSI) initiative, as well as partnering with Cognia for program improvement tools and school accreditation reviews.The sample population of this study was limited to member …

Pipecolic Acid And Novel Insights Into Cerebral Malaria, Akua E. Mensah

Theses and Dissertations

Cerebral malaria (CM), a severe manifestation of Plasmodium infection, prompts our investigation into the nuanced role of pipecolic acid in its pathophysiology. To unravel the molecular intricacies, we conducted in vitro lysine labeling techniques of mice infected with P. berghei ANKA parasites, and human P. falciparum grown in vitro, aiming to discern the impact of Plasmodium on pipecolic acid production. Previous observations indicated an elevation in pipecolic acid levels correlating with neurological decline in children with CM. In our study, confirming elevated pipecolic acid presence in the plasma and brain tissues of CM patients and the animal model of CM, …

The Effect Of Extended Saltwater Absorption And Uv Cure On The Compressive Properties Of Msla 3d-Printed Photopolymer Resin Samples With Printing Variations, Suzanne Dixon

Theses and Dissertations

Liquid Crystal Display (LCD) 3D printers, also known as Masked Stereolithography Apparatus (MSLA), is a type of vat polymerization printing technique that cures liquid resin into a solid object. This technique is relatively new. Consequently, there is a shortage of detailed research on the impact of long-term environmental exposure on the MSLA-printed materials. The research within this document informs engineers and scientists of resin compressive properties after extended exposure to saltwater and ultraviolet (UV) light. Saltwater absorption of the material was analyzed at atmospheric pressure, 30-psi, 60-psi, and 90-psi; the samples reached saturation in saltwater after 56 days. The variation …

The Icarus Paradox: Examining The Gender Bias In Leader Transgression, Pratibha Deepak

Theses and Dissertations

Despite the growing interest in leader transgressions due to their profound impact on organizations and their members, the boundary conditions influencing them remain unexplored. Consequently, this dissertation investigates the differential evaluation of leader transgressions based on such boundary conditions, focusing on the interaction between transgression type (integrity vs. competence), leader gender (female vs. male), and hierarchical status (supervisor vs. senior leader). Utilizing theoretical foundations from causal attribution theory, shifting standards, expectancy violation theory, and social identity theory, it is hypothesized that the impact of transgressions on organizational outcomes at multiple levels—including individual (perceived leader effectiveness), organizational (employee turnover intention), and …

Fabrication And Performance Demonstration Of Compact Adsorption Heat Pump, Faraz Ege

Theses and Dissertations

Addressing global environmental concerns requires a shift to eco-friendly energy sources, particularly in cooling applications where traditional vapor-compression systems rely on harmful refrigerants and electricity. Thermally-driven cooling systems, like adsorption heat pumps, offer promise with their environmentally friendly refrigerants such as water and use of low-temperature heat sources, including solar energy or waste industrial heat. This dissertation undertakes a comprehensive investigation into the development and optimization of compact adsorption heat pumps, aiming to address the efficiency and environmental challenges inherent in conventional cooling systems.

This research begins by introducing a novel insertion coating technique for fabricating MIL-101 (Cr) adsorbent layers …

Investigating The Impact Of Human-Centered Interface Design On The User Experience Of Mobile Device Users, Ruchir Gupta

Theses and Dissertations

In order to investigate the intricate interaction between interface design, user technological proficiency, and other components of the user experience, this research study used a mixed-method approach. The beginner user group—those with little experience or expertise with technology - were the main target audience. The important discovery emphasizes the substantial influence that careful design can have on improving the effectiveness and usability of interfaces for non-tech-savvy individuals. When using the suggested Interface B instead of the current Interface A, beginner participants' task completion times significantly improved, according to the user study. This underlines the significance of creating with the needs …

Evaluation Of Beach-Fx — Beach Nourishment Planning Model – Miami Beach Case Study, Brennan Chase Banks

Theses and Dissertations

Miami Beach, located on the Southeast coast of Florida, is a concerning location for coastal erosion because of the increasing intensity and frequency of tropical storms, nuisance flooding, and accelerated sea-level rise due to climate change. Miami Beach is famous for its beautiful beaches, making it a location of high interest for tourists, citizens, and investors. It is vital for coastal practitioners to accurately model coastal processes, beach evolution, and storm damage during the planning stage of coastal protection projects. The U.S. Army Corps of Engineers developed the Beach-fx model as a tool for engineers, planners, and economists to …

Development Of Chiral Lewis Base Catalysts For Chlorosilane-Mediated Asymmetric C-C Bond Formations, Changgong Xu

Theses and Dissertations

The chiral hydrazine is a crucial structural motif that serves as pivotal structural elements in numerous natural products and biologically significant molecules. We are particularly interested in the catalytic asymmetric reduction of hydrazones, as well as the catalytic asymmetric propargylation and allenylation of hydrazones, because they provide direct pathways to these enantio-enriched chiral building blocks. In this work, we will explore the potential of two different categories of chiral Lewis base catalysts in the said transformations.

Developed by another student in our group, axial-chiral 3,3’-triazolyl biisoquinoline N,N’-dioxides derived catalysts are tested and demonstrated its capability in activating various hydrazone …

System Identification For Motion Control Of Unmanned Aerial Vehicles Platform, Raj Ramesh Agarwal

Theses and Dissertations

Comprehensive research on Unmanned Aerial Vehicles (UAV) system identification for motion control parameters is presented in this thesis, with a focus on the necessity of precise control and improved performance. Using Pseudorandom Binary Sequence (PRBS) and Normally Distributed Random Numbers, it presents a unique technique for excitation of UAV dynamic systems. It also shows how effective random signals are in time-domain identification for precise control in a range of flying circumstances. The piece of research includes a thorough analysis and implementation of various approaches and its further improvements, highlighting the benefits and drawbacks of each. These approaches include the free …

4-Channel Spatially Multiplexed Communication System In Single-Core Optical Fibers, Ce Su

Theses and Dissertations

This dissertation delves into exploring and advancing spatial domain / space division multiplexing (SDM) technologies within single-core optical fibers, a frontier in optical fiber communications poised to meet the burgeoning global demand for data transmission. At the heart of this research is the pursuit to significantly enhance the capacity and efficiency of optical fiber communication systems without necessitating additional fiber infrastructure. This work unveils a new paradigm in optical fiber communications characterized by a pioneering 4-channel SDM system through a meticulous process encompassing theoretical modeling, computational simulations, design innovations, and rigorous experimental validations. Theoretical contributions include the development of refined …

Representation Learning For Generative Models With Applications To Healthcare, Astronautics, And Aviation, Van Minh Nguyen

Theses and Dissertations

This dissertation explores applications of representation learning and generative models to challenges in healthcare, astronautics, and aviation.

The first part investigates the use of Generative Adversarial Networks (GANs) to synthesize realistic electronic health record (EHR) data. An initial attempt at training a GAN on the MIMIC-IV dataset encountered stability and convergence issues, motivating a deeper study of 1-Lipschitz regularization techniques for Auxiliary Classifier GANs (AC-GANs). An extensive ablation study on the CIFAR-10 dataset found that Spectral Normalization is key for AC-GAN stability and performance, while Weight Clipping fails to converge without Spectral Normalization. Analysis of the training dynamics provided further …

Photo-Carbon Monoxide Releasing Molecules For Antibacterial Benefits In Vascular Grafts, Beste Caner

Theses and Dissertations

Globally, the annual hemodialysis procedures surpass 1.5 million, emphasizing the vital role of reliable vascular access methods. However, common challenges like access infections and clot-induced blood flow reduction necessitate innovative solutions. This study delved into the potential therapeutic role of carbon monoxide (CO) and its effects on both endothelialization and non-pathogenic bacteria causing infections. The primary focus was evaluating the impact of loading different concentrations of carbon monoxide-releasing molecules (CORMs), specifically CORM diketone 4 (DK4), within 2D spin-coated films on cultured E. coli and endothelial cells. Initial assessments of CO release kinetics from DK4-loaded films demonstrated that the 10% condition …

Unraveling The Physics Of Quasar Jets Using Hst Polarimetry, Devon Clautice

Theses and Dissertations

We present a multiwavelength study of three high-power FR II (quasar) jets -- 3C 273, PKS 0637-752, and 1150+497 -- with an emphasis on new high-quality Hubble Space Telescope (HST) optical polarimetry and Chandra X-ray Observatory imaging. Relativistic jets from active galactic nuclei transport energy and mass from the supermassive black hole’s accretion region out to Megaparsec-scale lobes, with effects that feedback into galaxy formation and cluster energetics. We build on recent work which has called into question our fundamental understanding of FR II jet physics, and suggest that highly-efficient particle acceleration must be taking place in situ …