Digital Commons Network^™

Assessing Tropical Mammal Diversity And Distribution Using Noninvasive Methods, Tiff L. Degroot

Dissertations, Master's Theses and Master's Reports

Central African tropical forests are rich in biodiversity and home to some of Earth’s most threatened mammals. However, mammals in the region are under increasing threat from habitat loss and degradation, coupled with an increased demand for wild meat. To conserve mammals, wildlife managers and community-led conservation efforts must understand the distribution and diversity of mammal communities. However, funding and logistical challenges make contemporary survey methods, e.g. ground surveys, difficult and expensive. Noninvasive methods allow efficient mammal diversity surveys with minimal field effort. Here, we use camera trapping and invertebrate-derived environmental DNA (“iDNA”) to assess mammal diversity and distribution in …

Understanding The Controls Of Seasonal Stream Temperature And Hydrological Monitoring Of Forested Watersheds In The Western Upper Peninsula Of Michigan, Eli A. Paulen

Dissertations, Master's Theses and Master's Reports

Accurately predicting stream temperature is vital to protect the environment and its most sensitive aquatic species. Tools for forecasting stream temperature rely on in situ data that affect thermal response of natural water systems. Stream and meteorological data were analyzed from the western Upper Peninsula of Michigan for the 2016-2023 water years to determine which factors affected stream temperatures. Through the application of multivariable linear regression models, our analysis identified air temperature as the primary determinant of stream temperature. However, the air-stream temperature relationship varied significantly over temporal scales, improving with increasing in time averaging. The air-stream temperature relationship was …

Novel Analytical Approaches For The Study Of Energy And Nutrient Flow In Streams, Michelle Catherine Kelly

Dissertations, Master's Theses and Master's Reports

This dissertation applied novel modeling, experimental and statistical approaches to overcome the challenges of measuring and analyzing energy and nutrient cycling in streams through 3 studies: (1) determining the predictors of respiration and denitrification in streams across the United States, (2) simultaneous estimation of denitrification and nitrogen (N) fixation rates, and (3) the impact of C lability metrics on the interpretation of C degradation in DOM incubation experiments. In the first study, I used predictive modeling approaches to show that respiration and denitrification were positively correlated across the landscape but were predicted by factors at different spatial scales. Denitrification rates …

Modeling Of Inverter-Based Resources For Hardware In The Loop Testing Of Protection And Control Schemes, Md Aamir Rahmani

Dissertations, Master's Theses and Master's Reports

High penetration of inverter-based resources (IBR) may cause the misoperation of protective relays due to the dynamic nature of fault currents fed by the IBR during short-circuit faults. Misoperation may cause damage to power system equipment and affect the reliability of the power system. This dissertation presents an in-depth investigation into the modeling of IBR in the context of transmission line fault scenarios to understand and analyze the characteristics of fault currents fed by the IBR. The research objectives encompass the development of reliable IBR models capable of accurately replicating fault current behaviors, designing IBR operation control schemes, and implementing …

Recovering Access Control Via Disk Forensics On Low-Level Flash Memory, Caleb J. Rother

Dissertations, Master's Theses and Master's Reports

In the history of access control, nearly every system designed has relied on the operating system (OS) to enforce the access control protocols. However, if the OS (and specifically root access) is compromised, there are few if any solutions that can get users back into their system efficiently. In this work, we have proposed a novel approach that allows secure and efficient rollback of file access control after an adversary compromises the OS and corrupts the access control metadata. Our key observation is that the underlying flash memory typically performs out-of-place updates. Taking advantage of this unique feature, we can …

Four Lessons To Build Upon: A Study Of Postsecondary Composition Classroom Curriculum, Tucker D. Nielsen

Dissertations, Master's Theses and Master's Reports

Soft skills in technical professions may be valued by employers, but post-secondary students engage with a dichotomy arguing against the blend of soft and hard skills. This study utilized activities with LEGO® bricks to determine how plausible kinesthetic learning methods are within university composition classes. Four in-class activities based on the class’s four core assignments were spread across the Spring 2024 semester at Michigan Technological university. Through written reflections, lists, posters, and photos of students’ builds, students practiced and demonstrated engagement with identified composition and critical thinking skills.

Two criteria (Audience Expectations and Genre Expectations, were not demonstrated as clearly …

Performance Characterization And Optimization Of A Point-Cloud-Based Path Planner In Off-Road Terrains, Casey D. Majhor

Dissertations, Master's Theses and Master's Reports

In this dissertation, I present a multifaceted study on the generation of artificial terrains using a multifractal method, and their use in autonomous ground vehicle (AGV) planning and navigation performance characterization in high-fidelity simulations, and automated parameter optimization.

My first contribution is a multifractal artificial terrain generation method leveraging the 3D Weierstrass-Mandelbrot function to control terrain roughness. We generate 60 unique off-road terrains while varying the fractal dimension and test the impact on vehicle traversal difficulty. Results show that increasing the fractal dimension decreases low-roughness areas, increases semi-rough and high-roughness areas, and decreases vehicle success rates while increasing vertical accelerations, …

Analysis Of Factors Affecting Engine Knock In Modern Spark Ignition Gasoline Engines To Improve Engine Efficiency, Siddharth Gopujkar

Dissertations, Master's Theses and Master's Reports

Spark ignition engine knock is an issue that has persisted for over a century. Knock prevents the spark in an SI engine to be deployed at the most optimum time in the engine cycle, which leads to a decrease in the efficiency of the engine. A reduction in the efficiency directly translates to increased emissions and fuel costs. This research looks at experimental works to analyze the impact of three separate factors on knock in an effort to minimize it and improve engine efficiency.

The first factor is fuel chemistry – how Research Octane Number (RON) and Motor Octane Number …

Continuous, Platform Purification Of Viral Products Using Aqueous Two-Phase Extraction, Natalie M. Nold

Dissertations, Master's Theses and Master's Reports

Cell and gene therapies, a ground-breaking class of drugs that can heal genetic diseases and cure cancer, often have treatment costs over $1 million. Most cell and gene therapies are delivered using virus-based delivery vectors, which are incredibly expensive to manufacture. Liquid chromatography is the favored method of viral vector purification since it is easily scalable and can be functionalized to purify by biospecificity, charge, hydrophobicity, or size. However, chromatography-based purification processes are highly expensive and usually only recover 20-50% of the viral vectors. There is currently no platform purification strategy for viral vectors due to differences in their surface …

Sustainable Materials For Environment − Multifunctional Material Made From Dead Leaves And Nanostructured Materials For Antibiotic Degradation, Siyuan Fang

Dissertations, Master's Theses and Master's Reports

As environmental pollution from industrial processes and human activities continues to rise, finding efficient approaches to recycle waste materials and degrade persistent contaminants becomes increasingly critical. Dead leaves, an abundant but underutilized biomass, present an opportunity for creating value-added materials if their biocomponents can be preserved and transformed. Simultaneously, antibiotics such as tetracycline are widely found in water bodies but pose serious ecological and health risks, necessitating effective degradation methods. This dissertation addresses these challenges by leveraging natural and nanostructured materials to develop multifunctional products and advanced photocatalytic processes.

Chapter 3 of this dissertation addresses the challenge of converting waste …

Multi-Functional Gelatin-Dithiolane Hydrogels For Tissue Engineering, Saad Asim

Dissertations, Master's Theses and Master's Reports

Biomaterials that integrate multiple functionalities, mimic the extracellular matrix (ECM) microenvironment to support cellular growth, and adhere robustly to damaged tissues are highly needed to advance tissue engineering. Protein-based biomaterials are promising due to their inherent biocompatibility, biomimicry, biodegradation, and cell-supportive properties. Herein, by leveraging the unique ability of dithiolanes to generate on-demand in-situ thiols, we developed a new class of dithiolane-modified, protein-based biomaterial that combines unique, seemingly opposing functions for tissue engineering. Dithiolane-modified gelatin, a model protein used herein, enabled photoinitiator-free photo-crosslinking to form multi-functional gelatin-dithiolane (GelDT) hydrogels, which displayed exceptional long-term stability in cell culture media (>28 …

V2i-Based Adaptive Collision Avoidance For Safety And Traffic Efficiency, Vaishnavi Balambeed

Dissertations, Master's Theses and Master's Reports

To leverage the growing communication and connectivity among modern vehicles, Vehicle-to-Vehicle (V2V) and Vehicle-to-Infrastructure (V2I) systems are increasingly being used to implement active safety applications. However, current research often overlooks the impact of algorithms such as collision avoidance on traffic flow efficiency. This work investigates the adaptation of a collision avoidance algorithm implemented in V2I to incorporate a variable time headway and spacing control strategy. The proposed approach aims to maintain higher average speeds among vehicles, lower individual vehicle’s waiting, and travel times in the vicinity of the infrastructural unit while simultaneously avoiding collisions; thereby enhancing both safety and traffic …

2d Direct Numerical Simulation Of Low-Prandtl Number Rayleigh-Bénard Convection, Reed Downs

Dissertations, Master's Theses and Master's Reports

A two-dimensional (2D) direct numerical simulation (DNS) of Rayleigh-Benard convection (RBC) was performed at Rayleigh number (Ra) = 10^6 and Prandtl number (Pr) = 0.021. The simulation was run using the Boussinesq approximation on a square grid of 5184 spectral elements using Nek5000. The simulation was started from a conductive state, with non-permeable, isothermal horizontal walls and non-permeable, adiabatic vertical walls. After reaching a steady state, where the Nusselt number (Nu) converged to 6.2, the simulation was run for 60 freefall-averaged dimensionless time units. Time-averaged thermal boundary layers on the top and bottom plates were found to consist of ejection, …

A Multimolecular Perspective On The Success Of Wolf Recovery And Relocation, Samuel D. Hervey

Dissertations, Master's Theses and Master's Reports

With global biodiversity in decline and many species isolated in fragmented habitats, conservation efforts increasingly rely on natural recolonization and translocation to restore ecosystems. These strategies face challenges such as genetic erosion and habitat limitations, highlighting the need for effective monitoring practices. This research assesses the success of wolf recovery initiatives by examining long-term genetic and genomic health using both traditional and advanced molecular methods. First, we investigated the genetic health of 19 gray wolves (Canis lupus) relocated to Isle Royale National Park to restore ecosystem balance. Initial genetic assessments with microsatellites found that these wolves had genetic diversity metrics …

Contribution Of Gaze Behavior In Reactive Balance Due To Decreased Environmental Lighting, Lily K. Hart

Dissertations, Master's Theses and Master's Reports

Introduction: Darkened environments pose an increased risk of falling. While considerable research has explored the role of gaze behavior in quiet standing and walking, less attention has been given to its contribution in reactive balance scenarios. The purpose of this thesis was to investigate the effect of dark environments on gaze behavior during reactive balance responses. Methods: Thirty young adults (mean age 25 ± 4.4 years) completed forward lean-and-release perturbations in two lighting conditions: 1) Light (~800 Lux) and Dark (0 Lux). Gaze behavior prior to perturbation was quantified using eye-tracking glasses to analyze potential differences between fixation duration, count, …

Data To Physics: Bridging Modeling Frameworks For Metastructures, Hrishikesh Suhas Gosavi

Dissertations, Master's Theses and Master's Reports

The effective attenuation of wave propagation in specific frequency ranges, known as bandgaps, makes metastructures valuable in various engineering applications. Traditionally, bandgap estimation has relied on physics-based models, which present challenges for complex metastructures where accurate material properties and geometric complexities make precise modeling difficult. This work introduces data-driven techniques for bandgap estimation, leveraging the dynamic behavior, particularly the Frequency Response Functions (FRFs) of unit cells, to calculate dispersion relations and couple unit cells through dynamic substructuring. This approach addresses the limitations of traditional methods by directly utilizing experimental data to characterize both longitudinal and flexural bandgaps.

To evaluate data-driven …

Analytical And Machine Learning Modeling Of Direct Carbonation Of Natural Silicate Minerals, William Hanson

Dissertations, Master's Theses and Master's Reports

The climate-altering effects of atmospheric CO₂ make it necessary to develop innovative technologies that can remove it from the atmosphere. Mineral carbonation is a scalable technology to sequestrate and store CO2 in a stable carbonate mineral form. The efficiency of the mineral carbonation process depends on both feed mineralogy and process parameters. Comprehensive modeling and prediction of mineral carbonation efficiency for different CO₂ – reactive rocks has not been achieved in the past. In this thesis work, analytical and machine learning models are developed to predict the carbonation efficiency of dunite reactions. It is found that random forest …

Investigating Microphysical Variability And Entrainment In Clouds Using Airborne Digital Holography, Machine Learning, And Large Eddy Simulations, Nithin Allwayin

Dissertations, Master's Theses and Master's Reports

Advancing our understanding of cloud microphysics—the processes governing cloud particles' formation, growth, and interactions—is essential for accurate weather and climate modeling. In this work, we investigate how droplet size distributions vary in a cloud and explore how microphysical properties such as droplet size and number concentration respond to entrainment and mixing.

In the first part of the work, a novel algorithm is developed combining hypothesis testing with density-based clustering to identify characteristic cloud droplet size distribution types in marine stratocumulus clouds. Applied to data from the airborne Holographic Detector for Clouds (HOLODEC), the algorithm successfully identifies a relatively small set …

Molecular Modeling Of Phenolic Resin For Carbon-Carbon Composites, Ivan Gallegos

Dissertations, Master's Theses and Master's Reports

One of the most difficult challenges associated with space exploration is terrestrial atmospheric reentry due to the high thermal loads generated. Carbon carbon (C/C) composites have been used as heat shielding materials due to their high strengthto- weight ratio and thermal properties and their applications include heat shielding for various high temperature environments. C/C composites are manufactured by polymer-infiltration pyrolysis (PIP) via cycles of curing and pyrolysis of a prepreg which can be costly and take up to several days. Thus, C/C composites ideal candidates for computationally-driven optimization techniques, such as a multiscale Integrated Computational Materials Engineering (ICME) approach, by …

Chemical Synthesis And Biological Application Of Sensitive Rna, Alexander T. Apostle

Dissertations, Master's Theses and Master's Reports

In the field of epigenetics - the dynamic collection of chemical modifications that overlay DNA/RNA - there is increasing interest in the potential for therapeutic and research-based utilization of the epitranscriptomics: those epigenetic modifications specific to RNA. Epitranscriptomics can give us a new approach to understanding and treating RNA viruses, like SARS-CoV-2. Given viruses are often found modified by human epitranscriptomic machinery, understanding how these modifications can modulate virulence is of high interest. We have shown that the N1-methyladensoine modification causes RNA synthesis termination in the SARS-CoV-2 replication complex, and thus may explain the differences in symptoms observed in individuals. …

Assessment Of Surface Waviness In A Wire Arc Additive Manufacturing Process, Shammas Mahmood Shafi

Dissertations, Master's Theses and Master's Reports

Wire Arc Additive Manufacturing (WAAM) is increasingly recognized for its ability to produce metal components with high deposition rates and efficiency, particularly in the aerospace and automotive sectors. However, one significant challenge that WAAM faces is achieving surface quality that complies with industry standards, as well as creating geometries that closely resemble the initial design. A crucial factor contributing to this challenge is surface waviness, which is an inherent characteristic of the WAAM process. This waviness arises from the geometry of the weld beads and the overlap distance between them. It can adversely affect the fusion quality of successive layers, …

Electrification Of A Heavy-Duty Off-Road Material Handler: Energy Savings And Emission Reductions, Bryant Goodenough

Dissertations, Master's Theses and Master's Reports

Federal regulations are driving the adoption of electrification technologies to reduce carbon dioxide equivalent (CO₂e) emissions, a metric that quantifies the global warming potential of various greenhouse gases in terms of carbon dioxide (CO₂). Although no specific CO₂ regulations exist for heavy-duty off-road machines, future reductions are likely, given stricter emissions standards for on-road vehicles. The heavy-duty off-road sector offers significant fuel-saving potential, as its focus has traditionally been on reliability and performance rather than fuel efficiency. This dissertation examines fuel and CO₂e savings opportunities on a heavy-duty off-road material handler, the Pettibone …

Synthesis Of Long Oligodeoxynucleotides, Yipeng Yin

Dissertations, Master's Theses and Master's Reports

Synthetic long oligodeoxynucleotides (ODNs) have found wide applications in diverse fields such as chemical biology, synthetic biology, and genes and genomes synthesis. Those applications leading to a significant demand for their production. However, traditional methods for purifying synthetic ODNs present notable drawbacks, particularly their inability to purify long ODNs, rendering long ODN synthesis challenging. To address these issues, chemical synthesis techniques for long ODNs coupled with non-chromatographic purification methods have been developed. This technology makes the purification of long synthetic ODNs feasible and offers a viable pathway for producing genes and genomes with extensive repeats or stable secondary structures, which …

The Impact Of Eye-Tracking On Mixed Reality Typing, Cecilia Schmitz

Dissertations, Master's Theses and Master's Reports

Accuracy and speed are pivotal when typing. We hypothesized that the lack of tactile feedback on midair mixed reality keyboards may adversely impact typing performance, especially when ten fingers are used to type. We examined the differences in performance when participants typed on a virtual keyboard using just their index fingers versus all ten fingers. The keyboard was deterministic (without auto-correct), relied only on the headset's egocentric cameras for sensing, and included symbol keys. We used a novel eye-tracking technique to mitigate accidental key presses. The technique was successful at reducing error rates, though participants still typed faster using their …

Implementing Associative Learning Using Neuromorphic Robot, Vinay Kumar Pillalamarri

Dissertations, Master's Theses and Master's Reports

Associative learning, a key cognitive process seen across the animal kingdom, enables organisms to form connections between stimuli and adapt their behaviors based on past experiences. A particularly powerful example is fear conditioning, where animals learn to associate a neutral stimulus with an aversive one, allowing them to predict and avoid potential threats. Inspired by this mechanism, this project implements associative learning on an unmanned ground vehicle (UGV) to develop adaptive behavior through neuromorphic principles. Utilizing Nengo for neural modeling, the UGV learns to associate visual (red color) and tactile (vibration) stimuli through Hebbian learning, a biologically inspired synaptic adaptation …

Computational Analysis Of Vascular Aneurysms, Seyedmostafa Rezaeitaleshmahalleh

Dissertations, Master's Theses and Master's Reports

Vascular aneurysms, such as intracranial aneurysms (IAs) and abdominal aortic aneurysms (AAAs), pose significant health risks, particularly upon rupture. Disturbed hemodynamics, characterized by swirling flow patterns, can lead to cellular and structural changes that disrupt normal physiological processes and contribute to destructive vascular remodeling. Integrating hemodynamic analysis into clinical assessments of aneurysms has become crucial, especially through patient-specific computational fluid dynamics (CFD) simulations based on medical imaging. However, the complexity of CFD tools presents challenges in model creation and post-simulation analysis, limiting their accessibility to clinicians.
This project aimed to advance aneurysm management by exploring the role of intraluminal thrombus …

Wet-Carbonation Of Rcas For Improved Carbonation Efficiency And Mechanical Properties Of Rca And Recycled Concrete, Zhao. Xiang

Dissertations, Master's Theses and Master's Reports

RCA typically exhibits weak interfacial transition zones (ITZ), high porosity, and micro-cracks due to residual mortar layers, resulting in suboptimal performance when reused in structural applications. To address these challenges, this study developed a wet carbonation process using glycine acid as an inducer. Glycine acid, containing carboxyl and amino functional groups, forms stable complexes with Ca²⁺ ions in RCA, increasing calcium ion solubility and thereby accelerating carbonation. RCA samples underwent carbonation in a glycine acid solution, followed by characterization using X-ray diffraction and scanning electron microscopy to evaluate mineralogical transformations and microstructural enhancements. The carbonation process promoted the formation of …

Advanced Mass Spectrometry Method Development And Applications For Assessment Of Traumatic Brain Injury And Legionella Pneumophila Dissinfection With Copper, Austin Chase Sigler

Doctoral Dissertations

"Pathological processes often involve complex biochemical changes which can be assessed using advanced mass spectrometry. In this present dissertation, two fields were studied: traumatic brain injury (TBI), and water contamination by L. pneumophilia. TBI is a pressing public health concern for which current clinical tools remain inadequate. We present newly developed mass spectrometric methods to access metabolites associated with blast induced TBI. We applied these methods to the biofluids of soldiers conducting explosives training. Significant changes in several metabolites were observed between pre- and post-blast specimens, including changes that increased with repeated exposure. These changes point to the possibility of …

Applications Of Computational Intelligence And Data Fusion Techniques For Biomedical Images, Anand Krishnadas Nambisan

Doctoral Dissertations

"The realm of melanoma diagnosis has been significantly advanced by deep learning (DL) techniques, yet the current approaches are not without limitations, including missed diagnoses and the challenge of interpreting these "black box" models. The research is comprised of three studies, each contributing uniquely towards advancing melanoma detection accuracy and interpretability. The first study focuses on improving the detection of specific dermoscopic structures through a deep learning-based segmentation approach, while the second study builds upon this by employing a fusion technique that combines traditional image features with advanced deep learning models. This method significantly improves melanoma detection, particularly in recall …

Development And Testing Of High Strength Scalable High Entropy Alloys, Hans Jakob Pommerenke

Doctoral Dissertations

"High entropy alloys have shown promise through their ability to be tailored to specific scenarios. From highly corrosive environments to precipitation strengthened alloys to radiation environments high entropy alloys allow tailor made alloys for every solution. New compositions are developed and tested but little work focuses on the processing effect choosing rather than using processing as a steppingstone to achieve properties without investigating the processing effects. This work focuses on single phase face-centered cubic alloys strengthened by processing and precipitation strengthening. In conjunction with the development of these alloys, the ability to scale production will be investigated and characterized to …