Physical Sciences and Mathematics Commons^™

Porous Silicon Photonics For Label-Free Interferometric Biosensing And Flat Optics, Tahmid Hassan Talukdar

All Dissertations

This dissertation uses porous silicon as a material platform to explore novel optical effects in three domains: (i) It studies dispersion engineering in integrated waveguides to achieve high performance group index sensing. With proper design parameters, the sensor waveguides can theoretically achieve 6 times larger group index shift compared to the actual bulk effective refractive index shift. We demonstrate the guided mode confinement factor to be a key parameter in design and implementation of these waveguides. (ii) It explores multicolor laser illumination to experimentally demonstrate perceptually enhanced colorimetric sensing, overcoming the limitations faced by many contemporary colorimetric sensors. Our technique …

Screening Of Near-Ir Surface-Enhanced Raman Scattering (Sers) Dyes Using Quick Freezing-Induced Aunp Aggregates (Qfiaas)., Carleigh A. Cimmerer

Forensic Science Master's Projects

Near-IR (NIR) surface-enhanced Raman scattering (SERS) is an emerging bioimaging technique that can be a safe alternative with a resolution better than current bioimaging techniques, such as MRI, CT, and PET. These can be hazardous with long-term exposure due to powerful magnetic fields or ionizing radiation. The success of NIR SERS bioimaging lies partially in the selection of highly sensitive NIR Raman reporters, which is essential to achieve highly resolved bioimaging of the body system. NIR Raman dyes must satisfy three important conditions: strong absorption in the NIR region, strong binding to the surfaces of gold nanoparticles (AuNPs), and excellent …

Mission Possible, Shashank Shah, Vijaya Sunder M

Asian Management Insights

Overcoming challenges to bring clean water to rural India.

The Executive’S Guide To Getting Ai Wrong, Jerrold Soh

Asian Management Insights

This article explores how we see AI and argues that we mostly get it wrong. In the process, it explains the reasons backed by social science research on why we tend to get AI wrong and illustrates the dangers of doing so from a managerial and law-making perspective. Some readers may also find the article useful as a guide on how and when to manipulate portrayals of AI in your favour.

Role Of E168d In M. Tuberculosis Igps Catalysis, Hedda Booter

Theses, Dissertations and Culminating Projects

Mycobacterium tuberculosis is a bacterium that affects the lungs and causes tuberculosis, infecting over 10 million people worldwide each year. Owing to the organism’s evolving drug resistance, existing antibiotics no longer combat the disease. The need to discover new drug targets has never been greater. Previous findings suggest that the protein IGPS (indole-3-glycerol phosphate synthase) in M. tuberculosis (MtIGPS) may be a target in the treatment of the disease. MtIGPS catalyzes the fourth step in the tryptophan biosynthetic process. The ability to create their own tryptophan is a major advantage that many bacteria have. The role of E168, in the …

The Growth Of Polarization Domains In Ultrathin Ferroelectric Films Seeded By The Tip Of An Atomic Force Microscope, Mohammad Zamani-Alavijeh, Timothy A. Morgan, Adrian V. Kuchuk, Gregory J. Salamo

Physics Faculty Publications and Presentations

Piezoresponse force microscopy is used to study the velocity of the polarization domain wall in ultrathin ferroelectric barium titanate (BTO) films grown on strontium titanate (STO) substrates by molecular beam epitaxy. The electric field due to the cone of the atomic force microscope tip is demonstrated as the dominant electric field for domain expansion in thin films at lateral distances greater than about one tip diameter away from the tip. The velocity of the domain wall under the applied electric field by the tip in BTO for thin films (less than 40 nm) followed an expanding process given by Merz's …

Understanding The Public Perception Of Available Scientific Resources In Coastal Southern Maine, James Gallagher

Senior Honors Projects

I have focused my education as an undergrad towards the effective communication of scientific fact to non-scientific groups. This area of study has recently been dubbed Science Communication and it encompasses the effective articulation, communication, and education of scientific topics to people who haven’t dedicated their lives to scientific study. A major component of effective Scientific Communication is understanding your audience and what kind of communication strategies are best for a chosen demographic.

I grew up in Ocean Park Maine, a small town on the coast of Southern Maine which drove my interest in Marine Science. With my experience in …

A Step Toward Reconstructing Climate Variability Druing The Last Ice Age Cycle In The Northeast Pacific Region, Blaine Lynch-Gadaleta

Senior Honors Projects

This study is designed as a step toward reconstructing the climate variability in the Northeast Pacific during the last ice age cycle, including the glacial and deglacial transitions. Reconstruction may also contribute to the regional picture of climate change and potentially provide new insights into the pattern of variability in the Northeast Pacific. Deep-sea sediment core AT26-19 09PC was collected west of the Juan de Fuca Ridge in the Northeast Pacific Ocean. Samples were analyzed in 1 cm intervals, representing approximately 300-year resolution. The abundance of mineral grains, planktonic foraminifera, and the polar foraminifera N.pachyderma was quantified using split aliquots …

Friedel-Crafts Alkylation Of Benzene With A Superacid Catalyst, Josh T. Cutright

Undergraduate Honors Theses

Long-chain alkylbenzenes are industrially synthesized precursors to commercial surfactants such as laundry detergent. The currently used catalysts in the processes of their synthesis are corrosive and harmful to the environment. These problems can be avoided utilizing heterogeneous highly acidic catalysts. Solid catalysts do not corrode equipment and are relatively simple to remove from the post-reaction mixture. Phosphotungstic acid (PTA) supported on silica gel could be a possible catalyst due to its high acidity with an estimated pKa ≈ -13. The catalyst PTA-SiO₂ was prepared via the sol-gel method to covalently embed it in a silica support. The catalyst was …

Development Of A Prototype Electron Detector For Use In Ucna+, Richard Mcdonald

Undergraduate Honors Theses

The UCNA Experiment at the Los Alamos Neutron Science Center (LANSCE) uses an electron spectrometer to observe angular correlations between the neutron spin and the momenta of β particles emitted during the process of β decay. These angular correlations give rise to an asymmetry determined by the ratio of two coupling constants, gA and gV . Combined with neutron lifetime measurements, these observations probe physics beyond the standard model through unitarity tests of the Cabbibo-Kobayashi-Maskawa Matrix. UCNA’s current spectrometer uses a multi-wire proportional chamber and a plastic scintillator coupled to four photomultiplier tubes (PMTs) by 2 meters of light guides …

Detecting The Intensity Of Denial-Of-Service Cyber Attacks Using Supervised Machine Learning, Abigail Hubbard

Undergraduate Honors Theses

Denial-of-Service (DoS) attacks are aimed at shutting a machine or network down to block users from accessing it. These attacks can be difficult to detect and can cost millions in damages or lost earnings. Since the first DoS attack occurred in 1999, the way DoS attacks have been launched has become more complicated, making them more elusive and harder to detect. The first step to detect and mitigate a DoS attack is for a system to identify the malicious traffic.

In this experiment, we aim to identify the malicious traffic within ten seconds. To do this the project was divided …

Extraction And Partial Purification Of An Antibiotic-Like Compound From The Soil Bacterium Rhodococcus Strain Kchxc3, Elizabeth Bond

Undergraduate Honors Theses

Rhodococcus bacteria have many secondary metabolic pathways that may produce novel natural products. The bacterium Rhodococcus strain KCHXC3 was isolated from a soil sample collected near Kingsport, Tennessee and was found to produce an inhibitory compound active against a broad array of bacterial species, including the Gram negative pathogen Shigella sonnei. The aim of this research is to extract and purify the compound for future structure elucidation. A mixture of compounds from 3 month old agar plates inoculated with strain KCHXC3 was extracted using ethyl acetate. The crude extract was then partially purified utilizing a Sephadex LH-20 column, followed …

Development Of Classroom Tools For A Risc-V Embedded System, Lucas Phillips

Undergraduate Honors Theses

RISC-V is an open-source instruction set that has been gaining popularity in recent years, and, with support from large chip manufacturers like Intel and the benefits of its open-source nature, RISC-V devices are likely to continue gaining momentum. Many courses in a computer science program involve development on an embedded device. Usually, this device is of the ARM architecture, like a Raspberry Pi. With the increasing use of RISC-V, it may be beneficial to use a RISC-V embedded device in one of these classroom environments. This research intends to assist development on the SiFive HiFive1 RevB, which is a RISC-V …

Pliocene Wood From The Gray Fossil Site, Owen Madsen

Undergraduate Honors Theses

The Gray Fossil Site in northeastern Tennessee preserves materials from a 5-million-year-old ecosystem, including wood from nearby trees. This study consists of three parts: conservation of wood remains, identification of taxonomic groups represented by the fossil wood, and measuring the organic content of fossil wood from the Gray Fossil Site. When excavated, wood specimens from the site are saturated due to a high local water table. After testing seven different techniques to dry wood specimens, wrapping a specimen in string and allowing it to dry slowly was the method least likely to cause warping and cracking. Microscopic examination of wood …

Intraday Algorithmic Trading Using Momentum And Long Short-Term Memory Network Strategies, Andrew R. Whitinger Ii

Undergraduate Honors Theses

Intraday stock trading is an infamously difficult and risky strategy. Momentum and reversal strategies and long short-term memory (LSTM) neural networks have been shown to be effective for selecting stocks to buy and sell over time periods of multiple days. To explore whether these strategies can be effective for intraday trading, their implementations were simulated using intraday price data for stocks in the S&P 500 index, collected at 1-second intervals between February 11, 2021 and March 9, 2021 inclusive. The study tested 160 variations of momentum and reversal strategies for profitability in long, short, and market-neutral portfolios, totaling 480 portfolios. …

Stumbling Into Virtual Worlds. How Resolution Affects Users’ Immersion In Virtual Reality And Implications For Virtual Reality In Therapeutic Applications, Brianna Martinson

Undergraduate Honors Theses

Studies of how users experience Virtual Reality (VR) have thus far failed to address the extent to which rendering resolution and rendering frame rate affect users’ sense of immersion in VR, including applications of VR involving simulators, treatments for psychological and mental disorders, explorations of new and nonexistent structures, and ways to better understand the human body in medical applications.

This study investigated if rendering resolution affected users’ sense of immersion in VR. This was conducted by comparing the responses of two groups, relative to two measures of participant immersion: (a) participant’s sense of presence and (b) participant’s sense of …

Understanding Biogeochemical And Physical Controls On Methane Air-Sea Exchange Fluxes In The Pacific Ocean, Sarah Raney

Master's Theses

Methane and trace element samples were collected on GEOTRACES GP15 Pacific Meridional Transect (PMT) cruise conducted between the Aleutian Islands (57 °N) and Tahiti (20 °S) from September to November 2018. Uncertainty in methane air-sea exchange fluxes was determined using a propagation of errors approach. Fluxes ranged from -0.88 to 4.9 µmol CH₄ m^-2 d^-1. Average CH₄ flux along the Alaskan margin was 2.2 ± 2.9 µmol CH₄ m^-2 d^-1. Methane fluxes decreased moving southward and increased to their open ocean maximum around 20 °N before declining in equatorial waters. Near …

Defining The Collapse Point In Colloidal Unimolecular Polymer (Cup) Formation, Ashish Zore, Peng Geng, Yuwei Zhang, Michael R. Van De Mark

Chemistry Faculty Research & Creative Works

Colloidal unimolecular polymer (CUP) particles were made using polymers with different ratios of hydrophobic and hydrophilic monomers via a self-organization process known as water reduction. The water-reduction process and the collapse of the polymer chain to form a CUP were tracked using viscosity measurements as a function of composition. A vibration viscometer, which allowed for viscosity measurement as the water was being added during the water-reduction process, was utilized. The protocol was optimized and tested for factors such as temperature control, loss of material, measurement stability while stirring, and changes in the solution volume with the addition of water. The …

Hydrogen Technologies, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Fact sheet about hydrogen technology and the Energy & Environmental Research Center’s (EERC's) National Center for Hydrogen Technology. Includes information about hydrogen as an energy and fuel source and past EERC hydrogen projects.

Core-Cm Williston Basin Carbon Ore, Rare Earth, And Critical Minerals, University Of North Dakota. Energy And Environmental Research Center

EERC Brochures and Fact Sheets

Fact sheet on the Carbon Ore, Rare Earth and Critical Minerals (CORE-CM) Initiative, an Energy & Environmental Research Center and U.S. Department of Energy project. Includes information on the importance of critical minerals and utilizing lignite from the Williston Basin. [This item is an outdated or superseded version and retained for historical purposes only. It may no longer reflect current information, policies, or practices.]

Studying Suspended Sediment Concentrations In The South Chickamauga Creek Of Chattanooga, Tn Using Satellite Imagery, Digital Image Processing, And Numeric Modeling, Abigail Faxon

Honors Theses

In recent years, Hamilton County, TN has experienced extensive urban growth. According to US Census data, Hamilton County welcomed more than 33,000 new residents in the last decade. There is increased concern about the environmental sustainability of Chattanooga’s urban growth because significant impervious surface development has taken place along the South Chickamauga Creek. This leaves the creek subject to increased urban runoff, which often carries sediments with different municipal pollutants. Thus, monitoring turbidity in the stream water is important to determine the sustainability of urban development in Chattanooga, TN. In this research, we have compared the viability of using different …

The Effects Of Dissolved And Suspended Solids On Freshwater Meiofauna, Jessica Cline

Honors Theses

Meiofauna include small-sized animals (< 1mm) distributed in all aquatic ecosystems on Earth, where they play fundamental trophic and ecological roles. The biodiversity of marine meiofauna and its links with anthropogenic activities is routinely investigated, however, freshwater communities are less known. This is particularly true for the Southeastern United States, which is greatly investigated and elected a hotspot of biodiversity for larger species but very little is known about the meiofauna. The purpose of this research is to reveal the biodiversity of meiofauna from the Tennessee River and test for potential correlations with anthropogenic activities. As a proxy for pollution, dissolved and suspended solids were considered in this study. The research hypothesis is that meiofaunal biodiversity would be affected by possible changes of dissolved and suspended solids in the water column. Possible mechanisms causing biodiversity shifts could be ascribed to osmotic stresses of animals to cope with variation in dissolved solids or, more indirectly, because different sunlight penetration caused by suspended solids would affect primary production. To test the hypothesis, water samples were collected from nine stations located along the Tennessee River in Hamilton County. Each station was visited three times, and, during each visit, environmental parameters (including dissolved and suspended solids) were measured. Meiofauna biodiversity (estimated as richness, community composition, and phylogenetic diversity) was revealed using a metagenomic approach. Statistical analyses were applied to test for possible correlations between the biodiversity estimates and the measured environmental parameters. Results show a high biodiversity of meiofauna with more than 200 amplicon-sequence variants distributed across 10 metazoan phyla. Environmental conditions are highly variable among stations and statistical analyses show that while both dissolved solids (TDS) and turbidity (suspended solids, NTU) did not significantly affect meiofauna biodiversity in the collected samples, various other water, and sediment metrics were found to be significant predictors of meiofauna biodiversity. In conclusion, the results of this project not only reveal for the first time the meiofauna biodiversity from the Tennessee River, but also suggest that meiofauna could be used as bioindicators for several anthropogenic activities in freshwater ecosystems.

Synthesis And Characterization Of Organometallic Complexes For Biological Imaging, Emily Stumbo

Honors Theses

Luminescent transition metal complexes are of interest for biological imaging applications due to their unique photophysical properties including large Stokes shift, long fluorescence lifetimes, and tunable emission. Altering ligand structure is a useful way to manipulate the charge transfer (CT) and mixed character states that give these complexes their photophysical properties. A series of organometallic complexes containing ligands with externally facing nitrogens has been prepared and synthesized. Complexes of the form Pt (II)(tbbpy)(C2-py), Re(CO)3(N^N), Ir(C^N)2(N^N), and Ir(C^N)2(N^O) have been studied for their potential application as biological imaging agents. The goal of this project is to compare the properties of these …

The Impact Of Water Infrastructure Inequality On Marginalized Communities, Indra Khalsa

Honors Theses

America’s current system of water infrastructure poses a threat not only to the environment but also to public health. The water crisis reveals the stark inequalities that exist from both an environmental justice and a social justice perspective. There is a growing concern that without adequate investment from federal resources, the problems related to this issue will only worsen the longer they are neglected. There is little information about how specific environmental and social factors combine with water infrastructure to create long-term infrastructure inequalities. However, this thesis explores the disparities in water infrastructure affordability, vulnerability patterns, and environmental hazards. It …

Using Nasa's Tess Mission To Search For Extremely Low Mass White Dwarf Stars, Corinna Peña

Undergraduate Honors Thesis Collection

Extremely low-mass white dwarf stars (ELM) are white dwarf stars with a mass lower than 0.45 solar masses that could not have evolved through normal processes within the lifetime of our universe. Therefore, these objects can only be created through a common envelope phase or a stable Roche lobe overflow while in a binary. These objects have periods between a few minutes to a few hours, so they are very short lived which makes them very rare. My goal for this project was to find these ELM stars by using NASA's Transiting Exoplanet Survey Satellite (TESS) data. I analyzed this …

Independent Dominating Sets In Unicyclic Graphs, Rachel Lopez

Theses, Dissertations and Culminating Projects

Wilf found the maximum number of independent dominating sets of a tree using algebraic methods, while Sagan gave an elementary proof. In this thesis, we maximize the number of independent dominating sets of unicyclic graphs, giving a new proof of a result of Jou and Chang. In our proof, we are able to reduce the problem to finding independent dominating sets of single-legged caterpillar graphs. We also study the number of single-legged caterpillar graphs, both oriented and unoriented, which are related to the Fibonacci Sequence. Finally, this thesis also examines the domination ratio in unicyclic graphs. The domination ratio is …

New Accurate, Explainable, And Unbiased Machine Learning Models For Recommendation With Implicit Feedback., Khalil Damak

Electronic Theses and Dissertations

Recommender systems have become ubiquitous Artificial Intelligence (AI) tools that play an important role in filtering online information in our daily lives. Whether we are shopping, browsing movies, or listening to music online, AI recommender systems are working behind the scene to provide us with curated and personalized content, that has been predicted to be relevant to our interest. The increasing prevalence of recommender systems has challenged researchers to develop powerful algorithms that can deliver recommendations with increasing accuracy. In addition to the predictive accuracy of recommender systems, recent research has also started paying attention to their fairness, in particular …

Modeling Functions Into An Angular Displacement Of An Elastic Pendulum, Brenda Lee Garcia

Theses and Dissertations

In this thesis we study the relation between analytic signals and a variety of pendulum systems. The representation of a signal as a pair of time varying amplitude and phase has been well studied and often related to linear mass spring systems. The differential equations describing pendulum systems are nonlinear and we provide analytical and numerical results regarding interpretation about the amplitude and the phase of signals in different pendulum settings. We report an explicit solution of the Elastic Pendulum problem in the case of linear phase. We develop an experimental procedure to piece-wise approximate bounded functions on a partition …

Synthesis Of Gpr119 Interacting Drugs For Treatment Of Type Ii Diabetes, Tien M. Tran

Theses and Dissertations

Type II Diabetes is one of the leading causes of death in the United States and is categorized by high blood glucose levels, insulin deficiencies, and inhibition. Located in the pancreas and intestine, the G-Protein Receptor 119 (GPR119) was noted to have an important effect on insulin secretion. Previous studies found that when the receptor is activated, insulin secretion was upregulated which is vital for type II diabetes treatment. Compounds AR437735 and AR437948 are the proposed agonist and inverse agonist pair that will be synthesized and tested for bioactivity to the receptor. It is theorized that the different double-bonded atoms …

Wayne E. Sabbe Arkansas Soil Fertility Studies 2021, Nathan A. Slaton

Arkansas Agricultural Experiment Station Research Series

Rapid technological changes in crop management and production require that the research efforts be presented in an expeditious manner. The contributions of soil fertility and fertilizers are major production factors in all Arkansas crops. The studies described within will allow producers to compare their practices with the university’s research efforts. Additionally, soil-test data and fertilizer sales are presented to allow comparisons among years, crops, and other areas within Arkansas.