Digital Commons Network^™

Investigation Of Combustion Properties Of Renewable Biofuel Blends Using A Hot Surface Ignition Assistant Device, Matthew Voigt

Graduate Thesis and Dissertation post-2024

With global warming, fuel supply, rising fuel prices, and energy security becoming major concerns for countries around the globe, many countries have been researching methods to reduce carbon emissions. One option being considered is using Bio-derived fuels as a possible alternative to modern jet fuels due to their ability to produce less emissions. However, while they do produce less emissions, they are also characterized by their low cetane numbers resulting in low reactivity requiring more energy to ignite, lower total heat release values, and longer ignition delays leading to engine problems such as knocking and power loss. Ignition assistant devices …

Towards Safe And Reliable Ai Models, Zihang Zou

Graduate Thesis and Dissertation post-2024

With the rapid advancement of artificial intelligence, its applications have become indispensable in our daily lives. Emerging advanced AI models, from general-purpose Large Language Models (LLMs) such as ChatGPT and Deepseek to domain-specific systems such as autopilot for autonomous vehicles, are changing the way we work and live by increasing efficiency and fostering innovation. However, these advancements also bring significant risks, as they may compromise data ownership or yield unreliable outcomes. In response, we focus on two critical areas: data safety and model reliability. To ensure data safety and promote lawful data processing, we investigate anti-neural watermarking techniques designed to …

Shock Tube Investigation And Chemical Kinetic Modeling Of Green Propellants For Space Missions, Marley Albright

Graduate Thesis and Dissertation post-2024

Hydrazine thrusters have been used for decades to land spacecraft on other planets. While its use is common, handling hydrazine is difficult due to its toxicity; this poses a risk to humans during testing and loading the propellant onto a spacecraft. Occupational Safety and Health Administration has limited human exposure to 1 part per million (ppm) of hydrazine per eight-hour workday. Green propellants are promising alternatives because they have lower toxicity but do not sacrifice performance. Green propellant technology has been demonstrated in space and future missions are planned, such as NASA’s Green-Propulson Dual-Mode technology demonstration. At the University of …

Structure-Property Relationship For Silver-Incorporated Cerium Oxide Nanoparticles, Shanza Nusrat

Graduate Thesis and Dissertation post-2024

Cerium oxide nanoparticles are known for their applications across several domains due to their biocompatibility, high oxygen storage capacity, redox behavior, and stability. However, their intrinsic electrical conductivity is relatively low, which can limit their performance in energy storage applications. Doping cerium oxide with transition metals has proved to enhance conductive properties and, hence, their performance in related applications. This research investigates the doping of cerium oxide with silver (Ag) and its correlation with the properties of the material. Silver-doped cerium oxide nanoparticles were synthesized by wet-chemical synthesis at room temperature by a facile procedure. Cerium oxide was doped with …

Computation-Efficient And Scalable Robotic Motion Planning Techniques To Address Dynamic Environmental Constraints, Apan Dastider

Graduate Thesis and Dissertation post-2024

In modern robotics, effectively computing optimal robotic control policies under dynamically varying environmental constraints poses substantial challenges and remains a unique research endeavor. To compute efficient and safe robotic motion planning while achieving collective objectives, robotic agents have to satisfy two criteria. First, the working robotic entity must be capable of handling a non-stationary working environment with dynamic obstacles and system constraints. Second, to ensure the real-time response, the robotic agent has to compute an effective control policy that meets a real-time learning performance. Despite significant advancements in motion planning with the appearance of extensive computing resources and advanced deep …

Assessing Driving Performance And Safety In Managed Lanes: A Human Factors Study On The Effects Of Buffer Separation Treatments With Delineators, Sharfuddin Ahmed

Graduate Thesis and Dissertation post-2024

Buffer separation with delineators is one of the commonly used separation treatments across US highways to distinguish managed lanes (ML) from general purpose lanes (GPLs). As MLs continue to be integrated into US highway system for improving traffic flow and reducing congestion, this separation method has become more popular due to its flexibility and cost efficiency over more robust physical separations. While past studies have explored the effectiveness and safety of buffer separations with delineators compared to other treatments, none have examined how specific changes within the buffer design—like separation width and delineator height—impact driver behavior. It is particularly important …

Evaluating Pedestrian Behavior In Response To Innovative Detection Messages And Wait-Time Indicators At Signalized Intersections: A Virtual Reality Study, Nada K. Ahmed

Graduate Thesis and Dissertation post-2024

Pedestrian safety at signalized intersections remains a growing concern in urban environments, necessitating effective communication between pedestrians and traffic control devices. Traditional approaches often prove inadequate in addressing these challenges. This study utilized virtual reality simulation to examine how innovative detection systems and wait-time indicators affect pedestrian behavior under varying environmental conditions. Ninety participants evenly distributed across three age groups experienced 18 crossing scenarios that differed by detection type, wait indication, crossing time, crossing distance, visibility, traffic density, and time of day. Key behavioral measures including start-up lost time, crossing speed, and total crossing duration were analyzed using linear mixed-effects …

Development Of A Laser Spectroscopic Device For Measurements Of Temperature And Speciation In Detonation Environments, Andrew M. Derusha

Graduate Thesis and Dissertation post-2024

Characterizing novel detonation-based combustion systems is critical to assessing new designs and improving the understanding of their unique operations. Due to the harsh nature of a detonation environment, industry-standard sensing and diagnostic tools can fail to provide adequate methods for in-situ quantitative measurements of key thermodynamic properties. Diagnostic equipment must adapt to meet the needs of new combustion systems. Laser absorption spectroscopy (LAS) is a technique commonly utilized in combustion research to provide such measurements in laboratory settings due to its precision, minimally invasive properties, and high data acquisition rates. To prepare such a sensor for use in a challenging …

Strengthening Community Resilience Towards Infrastructure Disruptions Due To Hurricanes, Tasnuba Binte Jamal

Graduate Thesis and Dissertation post-2024

Extreme events such as hurricanes can significantly disrupt infrastructures, leading to negative impacts on productivity, economy, and social wellbeing. Understanding community resilience against infrastructure disruptions in response to such events is crucial for effective preparedness, mitigation, and recovery efforts. The overarching problem addressed in this dissertation centers around enhancing community resilience against infrastructure disruptions due to hurricanes. Community resilience is defined as the ability of a community to return to normalcy following a disaster. One way to enhance community resilience is to strengthen its critical lifelines and infrastructure services (e.g., power, water, transportation, internet) and capital—to reduce the likelihood of …

Additively Manufactured Engineered Transparent Ceramics For Laser Gain Media, Ross Osborne

Graduate Thesis and Dissertation post-2024

Transparent ceramics (TCs) offer a key advantage over single crystals as solid-state laser materials, in that their composition can be spatially varied to improve laser performance. In this work, additive manufacturing (AM) techniques were applied to TC fabrication to produce laser gain media with engineered gain and index profiles. We have used direct ink write (DIW) to fabricate laser rods and channel waveguides and introduced ink-spraying, a new technique, to realize multilayer planar waveguides. Modifications to the DIW process, including the use of sacrificial drying layers to promote uniform drying, the optimization of the drying, burnout and calcination steps all …

Fundamental Mechanisms For Flame Acceleration And Detonation Phenomena, Rachel Hytovick

Graduate Thesis and Dissertation post-2024

Hypersonic propulsion via scramjets and detonation engines is enabled through the acute understanding of deflagrations, detonations, and multiphase interactions. Deflagrations are explored to understand the compressible flame regime for scramjet unstart and detonation transition in reacting systems. Compressible flames are experimentally classified with a comprehensive diagnostic suite combining particle image velocimetry (PIV), chemiluminescence, schlieren, and pressure measurements in a turbulent shock tube. Several gaseous fuels are explored to identify the universal mechanism responsible for flame compressibility and acceleration. The ability to compress deflagrations and accelerate the system to a detonation directly relies in the successful conversion of energy available to …

Optimizing Emissions And Sustainability Of Alternative Fuel Buses Using Machine Learning And Life-Cycle Modeling, Md Rezwan Hossain

Graduate Thesis and Dissertation post-2024

Public transportation is undergoing a critical transition as agencies seek to balance environmental responsibility, operational efficiency, and economic viability. Alternative fuel buses (AFBs), including electric, compressed natural gas (CNG), propane, and biodiesel, offer opportunities to reduce emissions and advance sustainability, yet their adoption raises complex trade-offs. High upfront costs, infrastructure constraints, range limitations, and variable real-world performance complicate decisions for fleet managers and policymakers. This dissertation addresses these challenges by integrating real-world operational data, life-cycle modeling, and machine learning within a multi-objective optimization framework to evaluate and optimize AFB deployment. Using detailed telematics and GPS datasets from Central Florida's transit …

Smart Urban Air Pollution Management Using Crowdsourced Big Data, Low-Cost Sensor Network And Aerial Remote Sensing, Md Hasibul Hasan

Graduate Thesis and Dissertation post-2024

Air pollution remains one of the most pressing environmental and public health challenges, especially in urban areas with dense populations and concentrated emission sources. Effective air quality management requires accurate information on emissions to guide control strategies and reliable exposure estimates to evaluate health impacts. This dissertation examines multiple sources of uncertainty in both emission and exposure assessments. Two major emission sectors were investigated: on-road motor vehicles and landfills. For on-road sources, detailed traffic information inferred from crowdsourced big data were leveraged to improve the estimation of traffic-related emissions. For landfills, the application of low-cost sensor and aerial remote sensing …

Addressing Vulnerabilities And Defesne Mechanisms In Transformer-Based Language Models, Mansour Al Ghanim

Graduate Thesis and Dissertation post-2024

Transformer-based Large Language Models (LLMs) have achieved remarkable success across Natural Language Processing (NLP) tasks, yet their increasing adoption has exposed critical vulnerabilities across input, model, and output layers. This dissertation systematically investigates these vulnerabilities and develops corresponding defenses, offering an end-to-end view of LLM security. First, we study model-level vulnerabilities through backdoor injection attacks that implant hidden malicious behaviors via hardware perturbations. We propose TrojBits, a hardware-aware attack that uses minimal bit-flips to insert trojans into models. Its three-stage design—Vulnerable Parameter Ranking, Hardware-Aware Attack Optimization, and Vulnerable Bit Pruning—success- fully compromises BERT and XLNet using only 64 parameters and …

Performance Analysis Of A Turbofan Intergrated With An Entropy-Minimized Heat Exchanger For Ammonia-Powered Aviation, Lucas K. Cavalcante

Graduate Thesis and Dissertation post-2024

Ammonia has emerged as a promising aviation fuel due to its carbon-free emissions, well-established production methods, and transportation infrastructure. However, challenges with its slow chemical kinetics and low flame speed necessitate the partial cracking of Ammonia to introduce hydrogen as a combustion promoter. This study addresses these challenges by designing and optimizing a tube bank heat exchanger to transfer heat from the Cooled Cooling Air (CCA) of the High-Pressure Compressor (HPC) to the Ammonia stream, facilitating the necessary cracking. Preliminary heat transfer calculations indicate insufficient heat in the CCA to achieve cracking temperatures, prompting an alternative approach: splitting the Ammonia …

Investigating Algal Toxin Occurrence And Water Quality Correlations In A Freshwater–Estuarine System, Sunday Sam Egon

Graduate Thesis and Dissertation post-2024

Cyanobacterial toxins, particularly microcystin-LR (MC-LR), present persistent risks in freshwater and estuarine environments, especially under flow-regulated system where hydrodynamics and biology interact complexly. This study investigates the occurrence of MC-LR across a lake–estuary water matrixes, sampling 13 sites from Lake Okeechobee through Caloosahatchee canal, river, and estuarine zones from March to September. Water quality parameters including conductivity, temperature, dissolved oxygen, chlorophyll-a, and phycocyanin were measured in situ. The concentration of MC-LR, and nutrients (ammonium, orthophosphate, and nitrite concentrations) were measured in the laboratory. Multivariate correlation, principal component analysis, and multiple regression were employed to determine dominant drivers of toxin occurrence. …

Mems-Based Airflow Sensor For Apnea Detection Using Time-Of-Flight Technique, Parvin Akhkandi

Graduate Thesis and Dissertation post-2024

Sleep is essential for overall human health, influencing cognitive, emotional, and physical well-being. Respiratory-related sleep disorders, particularly obstructive sleep apnea (OSA), require early detection and effective treatment to prevent serious health complications. This dissertation explores innovative advancements in respiratory monitoring sensor development techniques, aiming to improve the diagnosis and management of sleep disorders. The sensor in this work incorporates a pair of Thin-film Piezoelectric on Substrate (TPoS) MEMS resonators operating at ~25 MHz, embedded in two oscillator circuits where frequency variations reflect changes in temperature and humidity caused by respiratory airflow. By precisely measuring airflow travel time between the resonators, …

Autoignition Delay Times For Reformate Gas Mixtures From Methane Gas Engines, Matthew Fraze

Graduate Thesis and Dissertation post-2024

Methane slip is a prominent issue in natural gas reciprocating engines that are used in transportation and marine applications. The incomplete combustion that results in methane slip can be resolved with the introduction of hydrogen within the combustion mixture to improve methane oxidation and further enable combustion within the engine crevices where methane has previously remained unreacted. Steam Methane Reforming (SMR) is a common method used to produce hydrogen and can be used to design an onboard device to reduce methane slip from reciprocating engines. The development of this reformer device requires the validation of high-fidelity chemical kinetic mechanisms at …

Integrated Performance-Based Framework For Evaluating Alternative Containment Systems In Subtitle D Landfills Managing Coal Combustion Products, Poyu Zhang

Graduate Thesis and Dissertation post-2024

Designing landfill containment systems that remain effective over decades to centuries poses significant challenges in geoenvironmental engineering, especially for landfills managing coal combustion products (CCPs) with complex hydraulic and chemical behaviors. This dissertation aims to develop an integrated, performance-based framework for evaluating landfill barrier systems by combining numerical modeling, experimental leaching tests, and machine learning prediction. The first component assesses the equivalency of the Florida double liner system relative to the Subtitle D composite liner mandated by the U.S. Environmental Protection Agency (US EPA). Using field leakage observations and COMSOL Multiphysics-based numerical simulations, results demonstrate that the Florida system, when …

Characterization Of Turbulent Flames In Confined Combustors, Max Fortin

Graduate Thesis and Dissertation post-2024

As industry transitions to a net-zero carbon future, turbulent premixed combustion will remain an integral process for power generating gas turbines and are also desired for aviation engines due to their ability to minimize pollutant emissions. However, accurately predicting the behavior of a turbulent reacting flow field remains a challenge. To better understand the dynamics of premixed reacting flows, this study experimentally investigates the evolution of turbulence in a high-speed bluff-body combustor. The combustor operates across a range of equivalence ratios from 0.7-1 to quantify the role of heat release and flame scales on the evolution of turbulence as the …

Towards An Intelligent Speculative Software-Defined Networking, Ahmad Hariri

Graduate Thesis and Dissertation post-2024

Software-Defined Networking (SDN) separates the control and data planes, enabling better programmability of the control plane to predict, route, and schedule traffic at the data plane. Reactive SDN dynamically installs flow rules when a new flow arrives, making it adaptable to application dynamics. This design is well-suited for emerging low-latency applications like online gaming and AR/VR, which require millisecond-level response times for an acceptable quality of experience. However, Reactive SDN faces limitations, as each new flow triggers a miss, sending a Packet-in message from the switch to the SDN controller, increasing latency. To reduce delay, it's crucial to predict flow …

Characterizing Muscle Control As An Emg Visual Matrix, Peter W. Makary

Graduate Thesis and Dissertation post-2024

Evaluating electrical muscle activity patterns using surface electromyography (EMG) is a widely used technique to assess movement in research settings, but its use has not been translated to clinical settings. This study aims to investigate the potential of evaluating muscle activity control through a visual matrix display. EMG data from older and younger adults collected in a previous seated locomotor perturbation study was used to generate visual matrices representing their lower-limb ankle muscle activity. Visual matrices from each condition consist of 20x20 grids, where each axis represents activity from an individual muscle of muscle pairs, such as the tibialis anterior …

Aluminum Alloys For Laser Powder Bed Fusion Additive Manufacturing And Process Optimization By Machine Learning, Kevin Graydon

Graduate Thesis and Dissertation post-2024

Laser powder bed fusion (LPBF) additive manufacturing is a promising manufacturing technology enabling enhanced design freedom through layer-by-layer production. However, traditional, wrought aluminum (Al) alloys suffer from solidification cracking during LPBF processing and the initial printer parameter optimization process required for every novel or untested material is time and resource intensive. There exists a need to formulate Al alloys for LPBF and a method to reduce the resources consumed during initial printer parameter optimization studies. Al-9.5Ce-xMo (x = 0.2, 0.6, 1.0 wt. %) alloys have been designed specifically for LPBF utilizing the CALPHAD approach. Additionally, a neural network model was …

Modeling Data Metrics And Distributions For Representation And Efficient Transfer Learning, Li Ren

Graduate Thesis and Dissertation post-2024

Representation Learning and Transfer Learning are fundamental challenges in deep learning, particularly for downstream computer vision tasks. While existing research predominantly focuses on loss functions and network architectures, this dissertation explores how modeling distance metrics and data distributions can enhance representation and transfer learning efficiency in computer vision applications, specifically focusing on image captioning and retrieval tasks.

We make contributions primarily in three subareas. First, we develop an image captioning system that leverages geometric relationships among objects using a novel object graph structure, enhancing global visual representations for more accurate caption generation. We further incorporate adversarial learning to model data …

Haptics Based Grasping Of Novel Objects Using Robotic Manipulator, Nicolas C. Leocadio

Graduate Thesis and Dissertation post-2024

This work is focused on extending and demonstrating the generalizability of previous interactive perception-based work done on a model-free, non-neural algorithm for robotic gripper envelopment of objects using haptic feedback. Using a 6-axis force and torque sensor placed behind the wrist of a robotic arm's manipulator, appropriate motions are generated in order to achieve contact with, align the manipulator with, and place the manipulator around some desired object in a position where grasp is possible by simply closing the manipulator. The algorithm relies on generating restoring (reactive) and frictional forces by rapid multidirectional oscillation of gripper fingers about an initial …

Enhancing The Hardness Of The Multispectral Zns Transparent Ceramics Through Ga2s3 Incorporation: A Comparative Study Of Vapor Transport Deposition And Solid-Solid Reaction Methods, Hayat Soufiani

Graduate Thesis and Dissertation post-2024

Multispectral zinc sulfide (MS-ZnS) is an important optical ceramic widely used in broadband imaging systems due to its wide transmission range and relatively low cost. However, its modest mechanical properties limit its durability in harsh environments. This dissertation investigates two solute strengthening methods, vapor transport deposition (VTD) and diffusion coupling (DC), to enhance the hardness of MS-ZnS windows through Ga2S3 incorporation while maintaining optical transparency. The VTD process successfully incorporated gallium in the subsurface, resulting in up to 120 % increase in microhardness compared to untreated samples, but with slight discrepancies in lateral gallium distribution. The DC technique demonstrated superior …

Dordt University 2025-26 Catalog, Dordt University. Registrar's Office

Academic Catalogs

Academic Catalog for 2025-26

Front Matter

Dickinson Law Review (2017-Present)

No abstract provided.

The Method Is The Message: Movement Law And The Social Change Commons, Raymond H. Brescia

Dickinson Law Review (2017-Present)

Legal scholars have long sought to understand the relationship between social movements and the law. A new group of such scholars has argued that to better understand this relationship, and to advance social change that is effective, sustainable, equitable, and just, they must engage in dialogue with such movements to generate ideas that will catalyze that change. For those interested in generating ideas that can spark meaningful and lasting social change, such developments in legal scholarship represent an exciting evolution in the relationship between legal scholarship, legal scholars, and social movements: a relationship that appears to be growing stronger, deeper, …

Internet Search Engines’ Privacy Violations And The Lack Of Federal Regulation To Protect Consumers Rights, Elsa M. G. Rodriguez Ogando

Dickinson Law Review (2017-Present)

The United States’ current legal framework regarding internet search engines is disadvantageous to consumers. Federal privacy laws (although not encompassing search engines) grant businesses a strong legal basis in privacy claims and alibies for arbitrary behavior; these laws favor businesses over consumers. Moreover, state privacy laws empower nonspecific agencies to oversee privacy matters and enforce consumers’ rights. Thus, the U.S. privacy legal framework is in need of a new federal law that establishes consumers’ rights, as well as a federal agency dedicated solely to privacy matters. This Article proposes a federal law recommendation based on the standards of the California …