Digital Commons Network^™

Risk-Based Decision-Making Modeling For Wastewater Pipes, Sai Nethra Betgeri

Doctoral Dissertations

The dissertation research work described here has three primary objectives under risk-based decision making. (1) The development of a comprehensive sewer pipe condition rating model that incorporates many environmental, structural, and hydraulic parameters. (2) The development of a sewer pipe deterioration model used to predict future overall condition states of the pipe, as well as determining the probability of failure at any given age of the pipe. (3) The development of a comprehensive consequence of failure model that assesses the consequence of sewer pipe failure using economic, social, and environmental cost factors.

The Pipeline Assessment and Certification Program (PACP) was …

Silicon Nitride And Metalized Halloysite Nanotube For Enhanced Bacteriostatic Activity, Wound Healing, And Tissue Regeneration, Femi Alakija

Doctoral Dissertations

Metals such as titanium have been used in implants, but there are often cases of infection and rejection of the implant from the body. In the past decade, the use of metal nanoparticles has seen increasing demand as an alternative treatment for reducing microbial infections, leading to progress in orthopedic surgery and wound healing. Recent investigations have developed new biomaterial bone substitutes with novel structural, biological, and mechanical properties. Advanced ceramic materials, such as Si3N4, may fulfill all the requirements above and represent a promising alternative to metals or polymers. However, the above mentioned materials have limitations because they are …

Assessment Of Human Performance In Industry 5.0 Research Via Eye-Tracking And Cognitive Biases, Dana Isam Hamarsheh

Doctoral Dissertations

Manufacturing assembly is combining previously made components or subassemblies into a final finished product. The assembly process can be manual, hybrid, or fully automated. Human operators who are involved in assembly use their judgment to perform the process. They collaborate with the other work agents such as assembly machines, robots, smart technologies, and computer interfaces. The recent Industrial revolution, Industry 5.0, exploits human expertise in collaboration with efficient and accurate machines. Manufacturing facilities that feature Industry 5.0 work settings require higher expectations, higher accuracy, sustainability solutions, mass customization of products, more human involvement, and digital technologies in smart workstations. Given …

Peptide Carriers To Improve Uptake And Functionality And To Cross Bbb To Arrest Secondary Injury Post Tbi, Yashwanthi Yanamadala

Doctoral Dissertations

Cell-penetrating peptides (CPP) possess the ability to transport different cargos efficiently across the cell membrane. In this study, the ability of a CPP to cross the blood-brain barrier (BBB) and stably carry therapeutic components across the plasma membrane was assessed. The therapeutic efficacies were determined by the ability of the KAFAK conjugated anti-inflammatory peptide drug to inhibit the progression of secondary neuronal damage in a traumatic brain injury (TBI) model at 7-day post-injury (DPI) by inhibiting the production of inflammatory cytokines. A related study with minocycline and PgP-rolipram was conducted to improve the outcome in TBI models at 14 DPI. …

Research On Rubik's Snake And Quasi-Surfaces, Yu Chen

Doctoral Dissertations

In this dissertation, we have two topics in applied math. For the first one, we studied the Rubik’s snake by mathematical methods.

The Rubik’s snake is a toy invented by Professor Erno Rubik in 1981. It consists of right isosceles triangular prisms. Since the shape of a snake depends only on how we twist it, we can get a unique sequence from every snake. Those sequences record the way we twist snakes. In this dissertation, we will study the relations between some structures of the snake and the sequences.

For a snake with a specific structure, we will find out …

Chitosan-Based Composite For Wound Healing & Biomedical Applications, Abdul-Razak Masoud

Doctoral Dissertations

Polymer composites have witnessed increased research interest in the last decades, and the applications of these materials include drug delivery, tissue engineering, and wound bandages and dressings. Numerous polymers have been studied to fabricate the ideal wound dressing. Making these polymer composites biocompatible, porous, and bioactive with high absorption capabilities is critical to guide cell growth and differentiation and limit their detrimental effects on incorporated therapeutic molecules. This research work aims to address shortcomings of available wound dressings by fabricating a biocompatible, porous, bioactive, and antimicrobial dressing using chitosan (CTS) and carboxymethyl cellulose (CMC) polymers incorporated with zinc-doped halloysites (ZnHNT). …

Assessment Of Human Performance In Industry 5.0 Research Via Eye-Tracking And Cognitive Biases, Dana Isam Hamarsheh

Doctoral Dissertations

Manufacturing assembly is combining previously made components or subassemblies into a final finished product. The assembly process can be manual, hybrid, or fully automated. Human operators who are involved in assembly use their judgment to perform the process. They collaborate with the other work agents such as assembly machines, robots, smart technologies, and computer interfaces. The recent Industrial revolution, Industry 5.0, exploits human expertise in collaboration with efficient and accurate machines. Manufacturing facilities that feature Industry 5.0 work settings require higher expectations, higher accuracy, sustainability solutions, mass customization of products, more human involvement, and digital technologies in smart workstations. Given …

Clay Nanotube Drug Carrier With Enhanced Membrane/Skin Permeability, Mahdi Saleh

Doctoral Dissertations

Halloysite nanoclay is a natural material which is interesting for biomedical applications. Its unique physiochemical structure that forms the tubular shape originates from rolled sheets of aluminosilicate 15-20 times, such that alumina is inside and silica on the outside of the nanotubes, thus defining inner positive and outer negative charges. The dimensions of these tubules vary from 500-1,000 nm in length, external diameter 50-60nm, and inner lumen 12-15nm. Halloysites are biocompatible, cheap, and available in large quantities which suggests that these tubules can be used as effective nanocarriers. In this work, we exploited halloysite as a “nano-torpedo” for targeted drug …

Air Coupled Impact Echo Testing Of Buried Concrete Pipes, Yash Kumar Dhabi

Doctoral Dissertations

Concrete pipes constitute an integral part of the buried infrastructure, and non-destructive testing (NDT) plays an important role in their maintenance effort. Impact echo (IE) is a well-established NDT technique that is widely used for the investigation of concrete structures. In this technique, the thickness (or resonant) frequency is first measured by inducing (compression) P-wave into the structure using an impact source and recording the elastic wave generated using an accelerometer. From the knowledge of P-wave velocity of the medium, the unknown thickness and subsurface defects are then established. To effectively apply this technique, the transducer should be properly coupled …

Institutional And Leadership Factors Associated With Generating Funding For Research, Courtney A. Jarrell

Doctoral Dissertations

The strategic goal of increasing funding for research at a university is a complex objective dependent on various institutional and leadership factors. The purpose of this study was to develop an instrument to assist institutional leaders in assessing institutional and leadership factors for generating research funding at research-intensive universities. The research design included a modified Delphi panel to gain consensus on the comprehensive set of institutional and leadership factors and survey items associated with research productivity. The panel participants were experts in research administration from various institutions. Through a literature review and feedback from panel participants, the current researcher identified …

An Integrative Approach To Assess The Behavioral Impacts Of Noise Stimuli On The Australian Black Field Cricket, Teleogryllus Commodus, Jessica Briggs

Doctoral Dissertations

For acoustically oriented species, elevated levels of ambient sound can interfere with an organism’s ability to detect and assess acoustic signals and cues needed for making important decisions. Ambient noise, defined as any unwanted or non-focal acoustic signal, can impact behavior and decision-making by disrupting auditory sensory perception. As a result, noise in the context of this dissertation can be further delineated as excess sound that hinders a receiver's ability to detect and distinguish acoustic signals. Noise consists of either airborne or substrate-borne modalities or both. While many studies focus on the impact of airborne noise, many species have evolved …

Numerical Modeling Of Flexible Structures In Open Ocean Environment, Alexander Knysh

Doctoral Dissertations

The dissertation presents advancements in numerical modeling of offshore aquaculture and harbor protection structures in the open ocean environment. The advancements were implemented in the finite element software Hydro-FE that expands the Morison equation approach previously incorporated in Aqua-FE software developed at the University of New Hampshire.

The concept of equivalent dropper was introduced and validated on the example of a typical mussel longline design. Parametric studies for mussel dropper drag coefficients and bending stiffness contributions were performed for different environmental conditions.

To model kelp aggregates in macroalgae aquaculture, a corresponding numerical technique was developed. The technique proposes a modified …

Gelatin-Based Microporous Injectable Hydrogels For In Situ Stem Cell Encapsulation, Seth David Edwards

Doctoral Dissertations

In this dissertation, I developed and investigated gelatin-based microporous injectable hydrogels for the encapsulation of stem cells for multiple applications in cell delivery. Utilizing microgels composed from a mixture of gelatin and modified gelatin, I demonstrated the utility of a dual crosslinking mechanism, which enabled rapid gelation and tissue adhesion with improved cytocompatibility. Mesenchymal stem cells (MSCs) encapsulated in this hydrogel proliferated at a more rapid rate than in a nonporous counterpart, and showed increased immunomodulatory potential. Then, I investigated gelatin microporous hydrogel for the encapsulation of MSCs for bone tissue regeneration. Encapsulated cells more readily differentiated into osteoblasts (i.e. …

The Warriors' Views: Mid-Level Officers On American Interventions, Foreign Policy, And The Road To 9/11, 1993-2001, Michael Anthony Anderson

Doctoral Dissertations

When President William Jefferson Clinton took office, the United States had entered into a new era, though it was heavily influenced by almost a half-century of Cold War. Foreign policy staples had been embedded into United States foreign policy habits, influencing American decisions even as it tried to transition to a new global environment. The Cold War had left America, but America had a hard time leaving the Cold War. The nation had difficulty transitioning away from applying containment, relying on mutually assured destruction in preventing weapons of mass destruction attacks, and focusing on major conventional warfare when small-scale contingencies …

Highly Dispersed Metal Sites On Semiconductor Surface For Small Molecule Activation, Ehab Shaaban

Doctoral Dissertations

Heterogeneous catalysts have been extensively used in various chemical transformations that have important ecological and economical relevance. The rational design of such catalysts, however, is still not effectively implemented due to the ambiguity that encircles their structure-activity correlations. The origin of synergetic effects which make the binary system (metal/metal oxide) distinct from the individual components continues to elude researchers. In this work, binding and structural properties that emerge from metal/metal oxide interaction were investigated using in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and X-ray absorption spectroscopy (XAS). Different catalytic structures, including highly dispersed Cu sites on TiO2, were …

Low Current Electrospray Ionization Mass Spectrometry For Environmental Contaminants And Proteins, Taoqing Wang

Doctoral Dissertations

The introduction of electrospray ionization (ESI) in the 1980s has had a significant impact on the field of liquid chromatography-mass spectrometry (LC-MS), enabling the qualitative and quantitative analysis of small molecules in complex biological and environmental samples. NanoESI, developed in 1993, further improved sensitivity and reduced sample consumption. However, the detection limits for some environmental contaminants, such as perfluorooctanoate sulfonate (PFOS), require ppt-level detection, which necessitates preconcentration. Solid-phase microextraction (SPME) is a commonly used technique, and liquid-liquid extraction has shown promising results for water samples. Recently, the Li group has discovered femtoampere and picoampere ionization modes of ESI, which have …

Scanning Probe Microscopy Studies Of Petroleum Chemistry: Substrate-Dependent Catalytic Properties Of Mos2 And Automating Scanning Probe Microscopy With Machine Learning, Steven Arias

Doctoral Dissertations

With the growth of the population, society’s energy demands are mostly reliant on petroleum products that come from the refining of crude oil. Most of these refining reactions have been developed through averaging spectroscopic techniques, but scientists do not know exactly what is happening in these processes at the nano and atomic levels. This information is crucial when designing an efficient refining process that produces petroleum products that emit fewer harmful gases when combusting. Scanning probe microscopy techniques have become a powerful tool to look into the chemical structures found in petroleum products, to understand catalytic reactions in refining processes, …

Embedding Explicit Metacognitive Instruction Into The General Chemistry Curriculum: Equipping Community College Students With 21st Century Stem Competencies, Sonja Gamby

Doctoral Dissertations

This work describes the development, implementation, and assessment of a curriculum- embedded metacognition instruction model. The Talking About Learning is Key (TALK) module, a 10-week, discussion-based instruction module was initially integrated into a general chemistry course at a community college in Spring 2020. This case study was assessed qualitatively using a thematic analysis to characterize student posts and replies to the Learning Management System discussion board. Course outcomes between Spring 2020 – Fall 2021 were analyzed to determine what effect participation had on course completion and final grade.Finally, the generalizability of the module was investigated using a focused case comparison …

Synthesis, Modification, And Characterization Of Semiconductor Photocatalysts For Environmental Remediation, Norbert Okechukwu Okolie

Doctoral Dissertations

Semiconductor photocatalysis is a viable solution to tackle the increasing global demand for energy and the need for the recovery of wastewater in situ, without the need for fossil fuel dependence. Semiconductor materials active in the visible or near visible regions of light have been explored as suitable candidates for photocatalytic environmental remediation. Magnesium tantalates (MgTa2O6-xNx) were initially explored as promising candidates because their bandgaps can be brought well into the visible region by the introduction of nitrogen atoms as dopants. The synthesis of a highly ordered mesoporous nitrogen doped magnesium tantalate was achieved and the bandgap of magnesium tantalate …

Seismic Soil-Structure Interaction And Foundation Rocking In Unsaturated Ground, Matthew Michael Turner

Doctoral Dissertations

Strong earthquake motions often cause severe damage to buildings and foundation systems, during which the interaction between the soil, foundation, and structure may dominate the seismic response. Most shallow foundations are located on, or embedded in, unsaturated and partially saturated soil deposits. Unsaturated soil layers are particularly common in zones above the water table where water can rise through different mechanisms like capillary action. Additionally, the degree of saturation throughout a soil deposit can vary both seasonally and yearly due to groundwater table fluctuation related to infiltration and evaporation. Properties of soil layers below foundations impact the seismic response of …

Influences Of Students’ Use Of Calculus 1 Signs/Symbols On Students’ Assessment Scores, Phuong Wilk

Doctoral Dissertations

Mathematical notations not only contribute to but also confound the development of the understanding of mathematical concepts (Leinhardt, Zaslavsky & Stein,1990). Inaccurate use of calculus notations is likely to have a significant influence on student conceptual understanding and student assessment scores in the Calculus 1 course. This dissertation study aimed to examine whether or not the relationship between student’s ability to correctly write signs/symbols, interpret signs/symbols and interpret concepts using signs/symbols (students’ use of signs/symbols) and student assessment scores is statistically significant. The relationship between students’ use of sign/symbol and students’ grade performance was also examined under the effects of …

A Mixed Methods Approach To Social License To Operate For Aquaculture: Understanding How Broad Public Perceptions And Local Company Actions Influence Community Acceptance, Emily H. Whitmore

Doctoral Dissertations

With aquaculture development becoming increasingly important in meeting global food needs, understanding social dynamics of development is essential. Social license to operate (SLO), a concept that describes community acceptance and approval of incoming industry, offers a lens into these dynamics and possible strategies for successful development. Using a mixed-methods approach, this project aimed to investigate how broad public perceptions and local company actions influence social license to operate in aquaculture. First, a systematic literature review of SLO studies identified perceptions that would likely condition a community’s willingness to issue social license, independent of company actions. These predictors included environmental values, …

Deep Learning Based Predictive Models For Performance Enhancement In Bio Medical Applications, Sajila Dimagi Wickramaratne

Doctoral Dissertations

The medical field produces large quantities of multidimensional, complex, and often unstructured data. The timely interpretation of medical data is crucial for medical diagnostics. Machine learning applications are increasingly becoming popular with the ever-increasing computational ability and data availability. Machine learning methods can potentially find complicated relationships that may not be apparent in traditional clinical decision rule systems used in medical applications. Models deployed in medical applications need to be reliable, time efficient, and easy to interpret, thus making working with biosignals challenging in some cases.

The first part of the dissertation focuses on building predictive systems using existing data …

Modernism On The Edge Of The Anthropocene: The Ecological Imagination Of Forster, West, Warner, Woolf, And Eliot, Leanna Jean Lostoski-Ho

Doctoral Dissertations

By reading modernist literature on the edge of the Anthropocene, I argue in this dissertation that modernist authors, through the experimental aesthetics of their works, are able to articulate the beginnings of anthropogenic climate change in the early-twentieth century. The early-twentieth century, and particularly the interwar period, in which British modernist authors such as E. M. Forster, Rebecca West, Sylvia Townsend Warner, Virginia Woolf, and T. S. Eliot were writing coincides with the early-twentieth-century ramp up period of human activity rising to the level of a geological force before the beginning of the Anthropocene. While this dissertation does not argue …

A Comparison Of The Spectroscopically Determined Complex Refractive Indices Across Uv/Vis Wavelengths For Vanillic Acid From Two Aerosol Generation Methods, Vahid Hosseinpour Hashemi

Doctoral Dissertations

Aerosols are important because of their direct and indirect impact on the energy budget of Earth. Characterizing and understanding the physical, chemical, and optical properties of aerosols is beneficial to decrease uncertainties on the Earth’s energy budget estimations and improve climate models. Field studies characterize the real conditions and cases; however, controlling all variables, including the weather, is impossible, so only a snapshot can be obtained. Laboratory work can be a great support for field studies because controlling experimental conditions on a smaller scale is easier and targets can be achieved. Laboratory optical property studies of aerosol, even single chemical …

Type 3 Adenylyl Cyclase, Neuronal Primary Cilia, And Hippocampus-Dependent Memory Formation, Yuxin Zhou

Doctoral Dissertations

Primary cilia are microtubule-based cellular antennae present in most vertebrate cells including neurons. Neuronal primary cilia have abundant expression of G-protein coupled receptors (GPCRs) and downstream cAMP signaling components such as type 3 adenylyl cyclase (AC3). The deflects of neuronal cilia is associated with many memory-related disorders, such as intellectual disability. Thus far, little is known about how neuronal primary cilia regulate neuronal activity and affect hippocampal memory formation. Episodic memory is thought to be encoded by sparsely distributed memory-eligible neurons in the hippocampus and neocortex. However, it is not clear how memory-eligible neurons interact with one another to form …

Cyclodextrin Impedimetric Biosensors For The Detection Of Hydrophobic Metabolites, Zahra Panahi

Doctoral Dissertations

Sepsis is a complicated medical emergency and critically ill patients suffering from infectious diseases are at a high risk for developing and dying from sepsis. According to a recent (2019) cohort study from six United States hospitals, suboptimal care (e.g., delay in antibiotics, inappropriate antibiotic therapy) is responsible for 22.7 % of in-hospital sepsis-associated deaths. In September 2020, the World Health Organization called on the scientific community to develop rapid, effective, and affordable tools to improve diagnosis, surveillance, and treatment of sepsis. Our long-term goal throughout this project is to develop a cyclodextrin (CD) impedimetric tongue that can provide early …

New Porous Nanomaterials For Battery And Supercapacitor, Yixian Pei

Doctoral Dissertations

Lithium-Sulfur batteries have a high energy storage capacity while their sulfur cathode suffers large volume change, polysulfides dissolution and shuttle effect, and capacity fading during long-term cycling. To help lock sulfur and mitigate these problems, we introduced halloysite, a natural clay material with a nanotube format, to disperse and confine sulfur nanoparticles as well as to suppress the dissolution and migration of polysulfides. Halloysite was made conductive by covering it with a glucose-derived carbon skin. Sulfur nanoparticles were then trapped in both the lumen and outside surface of individual nanotubes with a loading dosage up to 80 %. In this …

A Primal Treatise Of Constant-Force Compliant Segment And Mechanism Design With Applications, Vamsi Lodagala

Doctoral Dissertations

"The evolution of compliant mechanisms propelled the development of constant-force mechanisms (CFMs) for various applications because of their unique characteristics. Many research endeavors have presented different techniques that often involve some optimization to design the CFMs. However, the mechanics of the generation of constant force at the elemental level is not well understood. This research effort theorizes and validates that simple, compliant segment with different boundary conditions, subjected to axial loading, produce near-constant force without the need for design optimization. Analytical models are developed based on the pseudo-rigid-body model (PRBM) concept to predict their force-displacement behavior, and to establish that …

Cfd Analysis For Beyond Bubbly Gas-Liquid Two-Phase Flows In A Large Diameter Pipe, Sungje Hong

Doctoral Dissertations

"Due to the complexity of multiphase flow phenomena, numerical analysis for multiphase turbulent flow is not as reliable as single-phase computational fluid dynamics (CFD). A literature review has revealed that the current efforts on multiphase flow simulation have focused on small diameter channels under very restricted flow conditions and have been conducted without identifying some important procedures. To expand CFD applications to a wide range of two-phase flow conditions in large diameter channels, this study aims to validate the current CFD models for vertical concurrent air-water two-phase flow simulations beyond bubbly flows. First, a numerical model developed to describe dynamical …