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Ratiometric Fluorescent Sensors Based On Non-Covalent Crosslinked Molecular Imprinted Polymers, Yuan Chen

Doctoral Dissertations

This thesis describes a series of optical chemosensors based on FRET between fluorophores on the polymer and the substrate. It involved the preparation of the polymer and nanoparticles for the chemosensor, and the sensing behavior based on the preparation methods.A photophysically inert sensor matrix was prepared by a robust and simple emulsion method. Stannic oxide encapsulated silica nanoparticles with diameters between 25 and 70 nm have been prepared by one-pot reverse-phase emulsion methodology. The constituents and core/shell morphology of the nanoparticles were demonstrated by electron microscopic technology, energy-dispersive X-ray spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS). X-ray diffraction (XRD) was …

Exploring The Mechanistic Effects Of Surface Characteristics On Uv254 And Bl405 Disinfection Efficacy, Castine Annastasia Bernardy

Doctoral Dissertations

The COVID-19 pandemic highlighted the need for more robust surface disinfection technologies. Photoinactivation efficacy for microbial pathogens and many surrogates has been well studied for water disinfection. However, there is a limited body of knowledge from research on surface disinfection applications of these technologies. The onset of the global pandemic resulted in a dramatic increase in surface disinfection devices being marketed to consumers, yet regulations for such devices have not been developed. This doctoral research studies the inactivation efficacy of two wavelengths, UV254 and BL405. The objective of this doctoral dissertation was to expand the body of knowledge required to …

Learning Trajectories From Human Demonstration Via Time Invariant Dynamical Systems, Paul Gesel

Doctoral Dissertations

Learning from Demonstration (LfD) is a powerful approach that enables users to program robots by simply demonstrating how to perform tasks. Rather than just mimicking the task, the robot should capture key characteristics of the task to adapt and generalize in various situations. Given that there is no explicit objective for each demonstrated task, optimal control methods cannot be directly applied. Two primary paradigms have emerged to overcome the limitation: 1) inverse learning and 2) imitation learning. In this dissertation, I formulate several time-invariant and stable dynamic system-based LfD models that leverage both inverse learning and imitation learning in the …

Exploring Protein Function And Stability: Case Studies On Cryoprotection And Thermal Stability Of Antifreeze Proteins, Enzyme Inhibition Of Sars-Cov-2 Main Protease, And B. Subtilis Protein Stability, Katarina Jovic

Doctoral Dissertations

In this work, I have explored basic questions related to protein structure, function, and stability, which are critical for understanding the fundamental mechanisms of biology. The dissertation is divided into four chapters, which are different topics I have worked on. In Chapters 1 and 2, I will discuss my work on two different antifreeze proteins, in Chapter 3 my work on the main protease from SARS-CoV-2 is presented, while Chapter 4 details the characterization of protein stability of four B. subtilis proteins. While the projects are distinct from one another, they all contribute to deciphering the molecular basis of life …

Understanding The Role Of Impounded Water Bodies In River Network Nutrient Exports In A Dynamic Landscape, Christopher Thomas Whitney

Doctoral Dissertations

Impounded water bodies are a significant component of aquatic networks and various forms have been studied extensively. However, knowledge gaps exist in the research on human-made dams and their reservoirs as well as beaver ponds as both uniquely affect water quality and nutrient exports in different ways. This study fills those knowledge gaps by investigating fluxes of all forms of dissolved nitrogen from small, human-made reservoirs at seasonal timescales. This study found that small reservoirs have a significant effect on nitrogen concentrations but this effect is seasonal and fluxes transported downstream are highly dependent on discharge. Removal of small dams …

Investigation Of Robust And Adaptive Control Methods For Systems With Uncertain Equilibrium States, Muhammad Hamad Zaheer

Doctoral Dissertations

Equilibrium states represent the natural resting point of dynamic systems in their state-space and provide vital information for the design of stabilizing feedback controllers for these systems. Stabilizing a system at an equilibrium state is desirable as it requires a zero steady-state control signal, resulting in lower energy consumption by the actuator. Mathematical models of real systems usually contain uncertainties that make it difficult to determine the exact values of these equilibrium states. Therefore, control methods requiring precise knowledge of the equilibrium state are ineffective in controlling systems when uncertainties make determining the exact value of the equilibrium state challenging …

A Global Gene Expression Approach To Exploring Rock Colonization By Blastococcus Saxobsidens, Ryan Patrick Wilmot

Doctoral Dissertations

Introduction: Blastococcus saxobsidens is an endolithic bacterium associated with biodegradation of stone monuments across the Mediterranean basin. Recently, strains of the bacterium have been isolated from high altitude deserts in Chile, volcanic glass in Iceland, and from masonry of several cultural heritage sites across Europe and the Americas. Blastococcus saxobsidens global dispersion has been linked to patterns of wind distributed dust particles. The physiology that this bacterium uses to colonize a wide range of rock types in such distinct locations has not been previously explored however. This project has established that B. saxobsidens colonizes and respires a variety of chemically …

Displaying Phenylalanine Ammonia Lyases On Bacillus Subtilis Spore Surface For The Treatment Of Phenylketonuria Through Oral Administration, Guo Wu

Doctoral Dissertations

Bacillus subtilis spores are formed in response to adverse conditions as a survival mechanism. These spores are in a dormant state and do not require any nutrients. Their DNA is wrapped with self-assembled multilayers of protective proteins. These spores are highly resistant to various harsh conditions. B. subtilis spores serve as a well-characterized model for studying endospore formation and have been developed as a platform system for displaying heterologous proteins of various functions. It has been demonstrated that proteins displayed on the spore surface can enhance their robustness and extend their shelf-life, including enzymes as robust biocatalysts and antigens as …

Engineering Studies Of An Experimental Open Ocean Seaweed Farm Design, Zachary Moscicki

Doctoral Dissertations

An experimental seaweed cultivation system was designed for offshore and exposed locations. Novel features were incorporated to address major barriers to the expansion of seaweed, including limited nearshore and sheltered marine locations and risk of marine animal entanglement. A novel modular mooring geometry was developed to improve stability, reliability, and spatial efficiency to achieve an economical and robust structure viable in high wave energy environments. Stiff composite (e.g. fiberglass) rods were used to replace components typically made of rope, including mooring lines and seaweed growth substrate (cultivation lines), as a means to mitigate risk of marine animal entanglement.

This dissertation …

Potential Vorticity Dynamics Driving Variability In Mean Tidal Currents Flowing Through Bounded Estuarine Channels, Katherine Anne Kirk

Doctoral Dissertations

Tidally induced pressure gradients in sea level drive mean estuarine tidal currents that can have horizontal spatial variability across a bounded channel or inlet. Strong cross-channel gradients in along-channel mean velocity set up extremums in the background potential vorticity that can support instabilities of tidal currents flowing through narrow, bounded estuarine channels and tidal inlets. In addition, conservation of potential vorticity including frictional terms, results in intensification of along-channel tidal currents over shallow lateral shelves. In the first part of this dissertation (Chapter 2), the dispersion equation of barotropic instabilities of tidal currents is analytically solved for simple bathymetry defined …

Financial Decision-Making Among Community College Leaders, Misty Dubois Slayter

Doctoral Dissertations

The purpose of this qualitative study was to learn about financial decision-making practices of community college chancellors. This study employed an instrumental case study with three embedded cases guided by organizational decision-making theory and distributive leadership perspective. Participants were community college chancellors within the same college system. Primary data for this study included questionnaire responses, semi-structured interviews, and document analysis using constant comparative method. Chancellors deemed budget shortfalls, programs, and self-generated revenue as major decisions. Chancellors in the study used financial reports to make decisions about programs, to design organizational structure and practice, and to construct college budgets—all of which …

Modeling And Analysis Of The Selective Lightning Strike Phenomenon At Locations In A Chemical Manufacturing Plant, Terver Maor

Doctoral Dissertations

This research was motivated by the overly simplified claims, from a previous study, that attempted to explain the cause of the reportedly repeated lightning strikes at certain locations in the chemical manufacturing plant. The findings, without any model, claimed that the electronic monitoring and control devices’ fire damage occurred, due to the raised electrical ground potential during lightning strikes. It proceeded that the raised electrical ground potential caused a power flow reversal, which exceeded the ratings of the affected electronic control modules, damaging them. This claim is inconsistent with published research work in the failure mechanisms of industrial control systems, …

Atomistic-Informed And Machine Learning-Assisted Crystal Plasticity Modeling For Materials Interface, Ibrahim Altarabsheh

Doctoral Dissertations

This dissertation presents a comprehensive study that addresses two critical challenges in the field of computational materials science and engineering from nano- to mesoscale. First, to overcome the well-acknowledged length scale limitation associated with atomistic simulations, a novel two-step approach is introduced for a probabilistic prediction of stress-strain curves in terms of material volume. The method combines Molecular Dynamics (MD) simulations and a multioutput Gaussian process (MOGP) with Bayesian analysis to model stress-strain behavior and predict stress and strain values. The model effectively captures the intricate three-stage curve shape exhibited in stress-strain plots, discerning key points such as yielding, hardening, …

Conditionally Automated Vehicles As A Safe And Productive Workspace, Nabil Al Nahin Ch

Doctoral Dissertations

Future automated vehicles will allow drivers to reclaim some of their driving time and perform personal or work-related activities while the car is in automated driving mode. However, traditional automotive user interfaces (UIs) are not designed to support such activities. For a vehicle to be considered a safe and productive workspace, we will have to explore how drivers can interact with emerging UIs in a car to engage in complex non-driving related tasks (NDRTs) and safely resume driving when needed. In the second chapter of this thesis, we present a user-elicitation study where we investigate how drivers would want to …

Acoustic Waveform Optimization For Three-Dimensional Object Geometries, Justin Ng

Doctoral Dissertations

In recent years, deep learning (DL) has become an increasingly important tool for many different types of classification, identification, and related problems including inverse radar and sonar applications. This thesis studies the degree to which radar and sonar systems may be optimized for DL algorithms in a theoretical setting. Most of the current existing literature found on using DL involve solving a full inverse scattering problem (ISP), that is to determine the properties and/or geometry of the scatter from nearly complete measurements of the scattered field. Methods suitable for use in two-dimensional space have been proposed and demonstrated with varying …

Non-Equilibrium Multiphase Particle Morphologies: Synthesis, Functionalization & Modeling, Yung-Chun Lin

Doctoral Dissertations

Waterborne technology highlights the advantage of using water as the dispersed media to replace the need for organic solvents. Emulsion polymerization is one of the most important techniques to produce functional polymer colloids of industrial importance. Besides the choice of monomers in the reaction, composite particle morphology significantly influences the mechanical properties of the materials in the applications of architectural coatings, adhesives, printing inks, and impact resistant plastics. Generally, emulsion polymerization produces spherical particles in the presence of water due to surface tension forces. In seeded emulsion polymerization, composite particles containing two incompatible phases can lead to various anomalous structures …

Resiliency And Sustainability Of Drinking Water Systems Under Long Term And Emergency Contamination, Taler S. Bixler

Doctoral Dissertations

This PhD dissertation is dedicated to the understanding and enhancement of the sustainability of public drinking water systems, addressing both emerging contaminants and emergency contamination events. A key focus is placed on comprehending the tradeoffs encompassing public health, economic, and environmental aspects associated with different actions aimed at improving system resiliency. By providing drinking water authorities with the tools and methodologies to evaluate available options, this research aims to empower decision-makers in their efforts to strengthen their drinking water systems against a myriad of threats.

This dissertation commences by investigating the tradeoffs related to the treatment of PFAS-contaminated water. The …

Black Phosphorus/Carbon Nitride Heterojunctions For Solar Fuel Generation, Nicholas Pollak

Doctoral Dissertations

Solar fuel generation has garnered attention in recent years as a renewable source for syngas (hydrogen and carbon monoxide) evolution. Difficulty in designing one-pot systems that can generate tunable ratios of hydrogen and carbon monoxide gases has persisted. In this thesis, a photocatalytic system for the generation of syngas under simulated solar irradiance is described that satisfies these challenges using black phosphorus (BP) and carbon nitride loaded with Co2+ active sites (Co@C3N4) to form a heterojunction. This thesis will present the ability to tune the syngas ratio by controlling the %wt of BP in the heterojunction. The oxidative power of …

Affecting Martensitic Transformation And Residual Stress Development Through Stress Superposition And Incremental Forming, Elizabeth Marie Mamros

Doctoral Dissertations

Stress superposition is defined as the incorporation of additional stresses into an existing manufacturing process during a single operation. In this thesis, experiments, simulations, and modeling of stress superposition in sheet metal deformation were investigated. Stress superposition can be used in manufacturing to reduce forming forces, increase material formability, and tailor the final part properties of products according to their intended applications, creating so-called functionally graded materials. Austenitic stainless steels (SS) were the focus due to their susceptibility to strain-induced phase transformation from austenite to martensite based on the stress state applied. In the first chapter, a novel cruciform specimen …

Robust Behavior Cloning For Multi-Step Sequential Task Learning By Robots, Mostafa Abdallah Mohamed Hussein

Doctoral Dissertations

This research is about learning high-level policies of multi-step sequential (MSS) tasks – such as activities of daily living – from demonstrations in a sample efficient manner. This research does not assume access to a simulator or an expert to provide more demonstrations. Learning a task policy in such a setting using state-of-the-art end-to-end approaches is sample inefficient due to a reliance on deep learning frameworks, which are known to require a large amount of data. Besides that, most imitation learning frameworks in robotics assume that a domain expert’s demonstration always contains a correct way of doing the task. Despite …

Physiological And Biochemical Analysis Of The Nitrogen Metabolism And Lead Treatment In Hybrid Poplar Clone Nm6 (Populus Nigra L. X P. Maximowiczii A. Henry), Medini Weerasinghe

Doctoral Dissertations

ABSTRACTThe first objective of my Ph.D. research was focused on understanding the reasoning for changes observed in the physiology and metabolism of the poplar plants in response to foliar application of nitrogen. Increased use of nitrogen in the soil in agriculture, in the form of nitrogen fertilizers, has helped to promote high-yield agriculture over the past decades. However, a large fraction of nitrogen applied to croplands in the form of fertilizer and manure ends up entering the freshwater system causing degradation of the water quality and eutrophication of groundwater, rivers, lakes, and coastal and marine ecosystems. Chemical fertilization is also …

An Analysis Of Fine-Scale Structure Within Ion Upwelling Processes, Niharika Godbole

Doctoral Dissertations

This dissertation showcases the projects that I have been involved with since I joined the Magnetosphere-Ionosphere Research Laboratory (MIRL) at the University of New Hampshire (UNH) in August 2017, under the guidance of my research advisor, Marc Lessard. Chapters 1, 2, and 3 of this dissertation are intended to provide the science background necessary to discuss the research projects presented in Chapters 4, 5, and 6 respectively.

The system that this dissertation addresses is complex and interconnected. In the most general sense, the Sun interacts with the Earth through the highly conductive, magnetized plasma that it emits, which directly shapes …

Building An Open Source Toolkit For Integrating Multiple Datasets For Seafloor Characterization And Habitat Mapping, Massimo Di Stefano

Doctoral Dissertations

Characterizing and mapping the seafloor and its features requires collecting and analyzing datasets of varied types and scales. Remotely-sensed data can increase our understanding of seafloor processes by providing insight into seabed geomorphology, substrate characteristics, etc., over large areas. Collecting direct observations or physical samples of the seafloor, also known as ground-truth data, holds the key to interpreting and validating remote sensing data. In this thesis, the case is made that by concurrently analyzing some or all of these datasets, knowledge about seafloor processes is gained more efficiently and I develop tools for seafloor habitat mapping.

In Paper I, I …

Securing Approximate Computing Systems, Pruthvy Yellu

Doctoral Dissertations

Approximate Computing (AC) techniques have been leveraged to improve computing performance and energy efficiency with minor degradation in accuracy. Different than conventional computing, AC allows the computation to deviate from the reference or deterministic execution behavior. Thus, AC has emerged as a new paradigm of computing systems, especially for the applications such as image processing, audio recognition, and artificial intelligence. The majority of research efforts on approximate computing focus on new approximation mechanism design and implementation, rather than examining the security vulnerabilities of AC systems. To fill this gap, we first analyze the potential security threats induced by the AC …

Non-Covalent Anchoring Strategies For Hybrid Electrocatalytic Systems, Peiyuan Zhao

Doctoral Dissertations

Global climate change, induced by increasing anthropogenic emission of heat trapping gases, has drawn great attention from scientists in recent decades. Reducing carbon emissions by decreasing the usage of fossil fuels and applying low/no carbon energy sources is a promising solution for a sustainable future. Electrocatalytic proton reduction to form hydrogen, using green electricity is a practical starting point.

Recent examples of heterogenized molecular catalysts have shown promise but stable anchoring to electrode surfaces is still a challenge. Heterogeneous electrocatalysis shows much more stability, but these systems lack the selectivity provided by a molecular system when more challenging reactions are …

Nonlinear System Identification And Motion Control System Design For Uncrewed Underwater Vehicles, Oguzhan Oruc

Doctoral Dissertations

Modeling and control of marine robotics have become a conspicuous research topic in the controlengineering community in the last decade. Remotely operated underwater vehicles (ROVs) are deployed and used in commercial, military, and scientific areas for many different purposes such as inspection and maintenance of submerged infrastructure, underwater surveillance/maritime, security, and ocean floor mapping most of which cannot be achieved effectively by human operators. However, to be able to operate these vehicles, an effective controller must be obtained, and an accurate dynamic mathematical model of the vehicle from which to design the controller is necessary. Although conventional modeling approaches are …

Threads, Buckets, And Impact: A Framework For Tool Accelerated Machine Learning Courses, Jonathan Adam Niemirowski

Doctoral Dissertations

Artificial intelligence and machine learning (ML) have exploded in use, accessibility, and awareness in the past few years, particularly with the release of ChatGPT in late 2022. Advances in end-user ML tools are accelerating the development of ML applications, lowering the technical barrier of entry for users outside of the computer science (CS) community. Access to ML education within STEM is mostly limited to upper-level computer science courses that have deep pre-requisite requirements or to introductory workshops that yield limited ML skills. Despite the critical need for ML education, there is a lack of guidance in instructional design for applied …

Alleviating Mathematics Anxiety For Middle School Students Using A Combined Intervention Approach Versus Only Using The Cognitive Intervention Approach For Increasing Mathematical Achievement: A Comparative Study, Patricia Anna Garcia

Doctoral Dissertations

Current research has found evidence of effective interventions for mathematics anxiety, both motivational and cognitive interventions can affect learning through instructional design and increased student engagement. Thus, this study investigated whether a combined (cognitive and motivation) intervention approach was more effective than only using a cognitive intervention approach for alleviating mathematics anxiety in middle-school students in order to develop a positive mathematical self-concept. The design used in this study was a comparison pretest-posttest study using the modified Abbreviated Math Anxiety Scale (mAMAS) to measure the participants’ level of mathematics anxiety and the STAR Mathematics diagnostic assessment to measure gradual mathematics …

A Case Study Of A School-Supported Extracurricular Activity's Influence On Stem Identity And Interest For Females, Letta Meyer

Doctoral Dissertations

Even though there has been a narrowing of the gender gap in STEM, there is still a pronounced gap in the physical sciences, engineering, and computer science. Females who persist in these fields have a strong STEM identity, including developing specific STEM interests. Females can develop STEM identity through long-term, active involvement in extracurricular STEM programs. Extracurricular STEM programs significantly impact the persistence of females in the STEM pipeline. This case study examined the effect of Science Olympiad, an extracurricular STEM program, on current high school students and alumnae’s perceptions of their STEM identity and personal specific STEM interest. Potential …

Alternative Approach For Assessment Of Hydraulic Design Basis For Pressure Pipe Liners, John Jacob Kraft Iv

Doctoral Dissertations

New product development requires stringent testing to ensure that strength and safety standards are met by the innovative materials. When developing a new pipe material, several factors have to be tested for. In addition to normal material characteristics such as elastic modulus of pipe materials, long-term hydrostatic strength (LTHS) and hydrostatic design basis (HDB) are needed. Tests for typical material characteristics are commonplace and can certainly be conducted in most lab facilities. In contrast, LTHS and HDB as described in ASTM D2992 are two tests that can prove very challenging to conduct. The current method requires a minimum of 18 …