Physical Sciences and Mathematics Commons^™

Visible Opacities Of S-Type Stars: The D³Φ–A³Δ Band System Of Zro, Peter F. Bernath, Manish Bhusal, Jacques Liévin

Chemistry & Biochemistry Faculty Publications

ZrO is a well-studied metal monoxide because of its astrophysical importance in characterizing S stars. The bands of the d³Φ–a³Δ system (γ system) with v′≤4 and v" ≤ 5 are rotationally analyzed using the PGOPHER program to provide spectroscopic constants. The high-resolution ZrO emission spectrum was recorded with a Fourier transform spectrometer using a high-temperature carbon furnace source. New ab initio calculations of the transition dipole moment were carried out in order to determine the vibronic band strengths. The spectroscopic constants, along with the band strengths, are used to calculate a line list for the γ system. This line list …

The Impact Of Biochar's Physicochemical Properties On Sorption Of Perfluorooctanoic Acid (Pfoa), Karen Ane Skjennum, Katinka M. Krahn, Erlend Sørmo, Raoul Wolf, Aleksandar I. Goranov, Patrick G. Hatcher, Thomas Hartnik, Hans Peter H. Arp, Andrew R. Zimmerman, Yaxin Zhang, Gerard Cornelissen

Chemistry & Biochemistry Faculty Publications

To better characterize properties governing the sorption of per- and polyfluoroalkyl substances (PFAS) to biochar, twenty-three diverse biochars were characterized and evaluated as sorbents for perfluorooctanoic acid (PFOA). Biochars were produced at various temperatures, using two different technologies, and made from sewage sludge, food waste reject, wood wastes, and one reference substrate (wood pellets). The biochars were characterized in terms of surface area, pore volume and pore size distributions, elemental composition, leachable elements, ash content, pH, zeta potential, condensed aromatic carbon (ConAC) content (determined by benzenepolycarboxylic acid (BPCA) markers), and their -OH functional group content (infrared spectroscopy). PFOA sorption isotherms …

Sea Level Rise Driven Groundwater Inundation: Effects Of Island Hydrogeology On Freshwater Lens Dynamics, Lauren K. Mancewicz

Dissertations, Master's Theses and Master's Reports

Groundwater inundation due to sea level rise poses a threat to fresh groundwater availability in coastal areas, and small islands are particularly vulnerable. On an island, when sea level rises, the freshwater lens also rises due to the difference in density between the salt and fresh groundwater. As the water table rises above the land surface it forms a lake and the water is exposed to additional evaporative losses, reducing the amount of fresh water available. This work aims to improve our understanding of groundwater inundation due to sea level rise and the impact of different hydrogeologic settings and phenomena …

Applications Of Independent And Identically Distributed (Iid) Random Processes In Polarimetry And Climatology, Dan Kestner

Dissertations, Master's Theses and Master's Reports

The unifying theme of this thesis is the characterization of “perfect randomness,” i.e., independent and identically distributed (IID) stochastic processes as these are applied in physical science. Two specific and mathematically distinct applications are chosen: (i) Radar and optical polarimetry; (ii) Analysis of time series in meteorology. In (i), IID process of a special kind, namely, with a distribution defined by symmetry, is used to link its multivariate Gaussian density to uniformity on the Poincaré sphere. This “statistical ellipsometry” approach is then used to relate polarimetric mismatches or imbalances to ellipsometric variables and suitably chosen cross-correlation measures. In (ii), recently …

Data Driven And Machine Learning Based Modeling And Predictive Control Of Combustion At Reactivity Controlled Compression Ignition Engines, Behrouz Khoshbakht Irdmousa

Dissertations, Master's Theses and Master's Reports

Reactivity Controlled Compression Ignition (RCCI) engines operates has capacity to provide higher thermal efficiency, lower particular matter (PM), and lower oxides of nitrogen (NOx) emissions compared to conventional diesel combustion (CDC) operation. Achieving these benefits is difficult since real-time optimal control of RCCI engines is challenging during transient operation. To overcome these challenges, data-driven machine learning based control-oriented models are developed in this study. These models are developed based on Linear Parameter-Varying (LPV) modeling approach and input-output based Kernelized Canonical Correlation Analysis (KCCA) approach. The developed dynamic models are used to predict combustion timing (CA50), indicated mean effective pressure (IMEP), …

Dependence Of Energy Transfer On Curvature Similarity In Collisions Involving Curved Shock Fronts, Justin Cassell

Dissertations, Master's Theses and Master's Reports

In high-speed collisions of projectiles, pressure exerted by a resulting shock wave is so high that even solids begin to flow and hydrodynamics becomes relevant. Jetting results from hydrodynamic instability driving the evolution of an interface following shock loading. Our emphasis in this dissertation is mitigation of instabilities via several shocks and, specifically, the transfer of energy from a shock wave to another object. To that end, in 2022 and 2023 while on-site, we adapted Lawrence Livermore National Laboratory (LLNL) to explore the effects of shock front geometry on the transfer of energy during shock collisions via numerous computer simulations. …

The Integration Of Neuromorphic Computing In Autonomous Robotic Systems, Md Abu Bakr Siddique

Dissertations, Master's Theses and Master's Reports

Deep Neural Networks (DNNs) have come a long way in many cognitive tasks by training on large, labeled datasets. However, this method has problems in places with limited data and energy, like when planetary robots are used or when edge computing is used [1]. In contrast to this data-heavy approach, animals demonstrate an innate ability to learn by communicating with their environment and forming associative memories among events and entities, a process known as associative learning [2-4]. For instance, rats in a T-maze learn to associate different stimuli with outcomes through exploration without needing labeled data [5]. This learning paradigm …

Integrating Arcgis And Redux Using Middleware, Vishnu Vardhan Reddy Rapuru

Dissertations, Master's Theses and Master's Reports

The integration of ArcGIS with Redux through middleware presents a novel approach to managing state in geospatial applications. This report outlines the process and benefits of combining ArcGIS’s robust mapping and analytics capabilities with Redux’s predictable state container for JavaScript apps. It begins with an introduction to both technologies, followed by a detailed discussion on the architecture design, focusing on the role of middleware as the linchpin in this integration[1]. The paper highlights the benefits, such as improved state management and application performance, and addresses the challenges encountered during the integration process. Implementation details are provided, including the setup of …

Discontinuous Galerkin Methods For Compressible Miscible Displacements And Applications In Reservoir Simulation, Yue Kang

Dissertations, Master's Theses and Master's Reports

This dissertation contains research on discontinuous Galerkin (DG) methods applied to the system of compressible miscible displacements, which is widely adopted to model surfactant flooding in enhanced oil recovery (EOR) techniques. In most scenarios, DG methods can effectively simulate problems in miscible displacements.
However, if the problem setting is complex, the oscillations in the numerical results can be detrimental, with severe overshoots leading to nonphysical numerical approximations. The first way to address this issue is to apply the bound-preserving
technique. Therefore, we adopt a bound-preserving Discontinuous Galerkin method
with a Second-order Implicit Pressure Explicit Concentration (SIPEC) time marching
method to …

Optimizing Php Api Calls With Pagination And Caching, Parsharam Reddy Sudda

Dissertations, Master's Theses and Master's Reports

The Keweenaw Time Traveler (KeTT) project is devoted to mapping the historical and social landscapes of the Keweenaw Peninsula. During the project, it was discovered that the server-side performance needed improvement. To address this issue, the "Optimizing PHP API Calls with Pagination and Caching" initiative was launched. This initiative focused on refining API calls, implementing server caching and pagination, and fortifying security against common vulnerabilities. The project successfully mitigated risks associated with SQL Injection and XSS through meticulous code enhancements while improving error handling. Additionally, the introduction of Scroll-Induced Pagination optimized data delivery, significantly reducing response times, and elevating the …

Study Of Particle Accelerators In The Universe With The Hawc Observatory, Rishi Babu

Dissertations, Master's Theses and Master's Reports

HESS J1809-193 is an unidentified TeV source discovered in 2007 by the High Energy Stereoscopic System(H.E.S.S.) Collaboration. The emission originates in a region that is rich in cosmic-ray accelerators, including several supernova remnants and pulsars, including SNR G11.1+0.1, SNR G11.0-0.0, and the young radio pulsar PSR J1809-1917. Originally classified as a pulsar wind nebula candidate, recent studies show the peak of the TeV region overlapping with a system of molecular clouds and revising the original classification for other scenarios, including a pure hadronic scenario. This dissertation presents the morphological and spectral study of HESS J1809-193 using 2139 days of data …

Chemical Synthesis Of Sensitive Dna, Komal Chillar

Dissertations, Master's Theses and Master's Reports

Over the past decades, researchers have tried various chemical methods to synthesize modified oligodeoxynucleotides (ODNs, i.e. short segments of DNAs). Traditional ODN synthesis methods require strong basic, and nucleophilic conditions for the deprotection and cleavage of the ODN from the solid support. However, the sensitive ODNs containing labile functionalities are vulnerable to such harsh conditions. Sensitive ODNs have a wide range of applications in research and pharmaceuticals. To synthesize sensitive ODNs, researchers devised different strategies but no practical methods have been developed. To overcome these challenges, we developed alkyl Dim alkyl Dmoc technology. This innovative technology uses weakly basic and …

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

Dissertations, Master's Theses and Master's Reports

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

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

Dissertations, Master's Theses and Master's Reports

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

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

Dissertations, Master's Theses and Master's Reports

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

Establishing A Two-Color Fluorescence Probe Assay For The Simultaneous Screening Of Glut5 And Glut2 Fructose Transporters In Live Cells, Oluwanifesimi Mary Afolabi

Dissertations, Master's Theses and Master's Reports

The mammalian facilitative glucose transporter (GLUT) family comprises 14 members that mediate the transport of hexoses across cell membranes. GLUT5 is the only member specific to fructose, and together with GLUT2, which transports fructose in addition to glucose, they make up the primary fructose transporters in humans. This study introduces a novel two-color fluorescence assay designed to simultaneously monitor the activity of GLUT5 and GLUT2 in live cells. 2,5-anhydro-D-mannitol (2,5-AM) a GLUT5 targeting compound has facilitated the development of various fructose-mimicking probes with a wide range of properties, such as radioactive imaging, fluorescent, photoactive, and drug delivery capabilities. Effective and …

Programming By Voice, Sadia Nowrin

Dissertations, Master's Theses and Master's Reports

Programmers typically rely on a keyboard and mouse for input, which poses significant challenges for individuals with motor impairments, limiting their ability
to effectively input programs. Voice-based programming offers a promising alternative,
enabling a more inclusive and accessible programming environment. Insights from interviews with motor-impaired programmers revealed that memorizing unnatural commands in existing voice-based programming systems led to frustration. In this work, we explore how programmers naturally speak a single line of code and present a comprehensive methodology for a voice programming system aimed at making programming more accessible for diverse users. To achieve this, we adopted a two-step pipeline. …

A Virtual Time Driven Simulator For Devs Models, Ronald R. Stempien

Dissertations, Master's Theses and Master's Reports

When simulating a system that includes some software component, simulation authors are faced with the problem of how to appropriately model the software within the simulation. While many formal methods for modeling software exist, in some contexts these may not be appropriate or viable for a given simulation. Instead, simulation authors may model a computer within the simulation, and run the software in question “as is” on the modeled machine. In this work, we introduce a theoretical framework to allow for the use of hardware virtualization technologies as a hardware accelerator for CPU models in Discrete Event System Specification (DEVS) …

Dynamic Memory Management For Key-Value Store, Yuchen Wang

Dissertations, Master's Theses and Master's Reports

To minimize the latency of accessing back-end servers, modern web services often use in-memory key-value (k-v) stores at the front end to cache frequently accessed objects. Due to the limited memory capacity, these stores must be configured with a fixed amount of memory. Consequently, cache replacement is required when the footprint of the accessed objects exceeds the cache size.

This thesis presents a comprehensive exploration of advanced dynamic memory management techniques for k-v stores. The first study conducts a detailed analysis of K-LRU, a random sampling-based replacement policy, proposing a dynamic K configuration scheme to exploit the potential miss ratio …

Model Guided Memory Optimization For Key-Value Caches, Daniel Byrne

Dissertations, Master's Theses and Master's Reports

Modern web services deploy key-value caches to store popular requests to backend systems. As such, how the cache stores data impacts both the cache miss ratio and throughput. Therefore, in this thesis, we introduce and apply cache modeling techniques to optimize the memory organization of a key-value cache to improve overall cache performance.

Specifically, we begin with a single-level key-value cache and use miss ratio curves to adjust the memory assigned to the residing applications dynamically. This leads to an improvement in miss ratio up to 25% over state-of-the-art techniques and an 8.8% improvement in cache throughput. We then consider …

Response Of Open Volcanic Systems To Static Stress Changes, Aimee Zimmerman

Dissertations, Master's Theses and Master's Reports

Large earthquakes of magnitude 7.0 or greater can alter volcanic emissions and even trigger eruptions at nearby volcanoes. The stress changes imparted by large earthquakes can cause otherwise stable conditions within the magmatic system to be disturbed, potentially inducing volcanic activity. The extent of the triggering potential is still unknown due to insufficient understanding of the mechanisms involved. We model static stress changes for 174 earthquake-volcano pairs from 2000-2023 at volcanoes within 500 km, computing changes in both the normal stress perpendicular to the direction of horizontal maximum stress and dilatational strain. We then use thermal satellite data to measure …

Hydrologic Pathways Of A Northern Hardwood Catchment In The Great Lakes Basin Using End Member Mixing Analysis, Cory C. Burkwald

Dissertations, Master's Theses and Master's Reports

This study investigated the seasonality of hydrologic pathways, the role of wetlands in streamflow generation, and how hydrologic pathways affect the export of nutrients by streamflow in the Sturgeon River using endmember mixing analysis. The results indicated that streamflow consists of three main components: shallow subsurface water from wetland soils, shallow groundwater, and surface runoff from precipitation. Snowmelt plays a dominating role in regulating stream water chemistry (~80% volume at peak) during the snowmelt season and likely also after that. Wetland soils store snowmelt, together with rainwater though the fraction is unknown, and then gradually release through summer in the …

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

Dissertations, Master's Theses and Master's Reports

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

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

Dissertations, Master's Theses and Master's Reports

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

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

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

Dissertations, Master's Theses and Master's Reports

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

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

Dissertations, Master's Theses and Master's Reports

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

Synthesis Of Long Oligodeoxynucleotides, Yipeng Yin

Dissertations, Master's Theses and Master's Reports

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

Nitrogen Uptake Rates And Phytoplankton Composition Across Contrasting North Atlantic Ocean Coastal Regimes North And South Of Cape Hatteras, Yifan Zhu, Margaret R. Mulholland, Peter W. Bernhardt, Aimee Renee Neeley, Brittany Widner, Alfonso Macías Tapia, Michael E. Echevarria

OES Faculty Publications

Understanding nitrogen (N) uptake rates respect to nutrient availability and the biogeography of phytoplankton communities is crucial for untangling the complexities of marine ecosystems and the physical, biological, and chemical forces shaping them. In the summer of 2016, we conducted measurements of bulk microbial uptake rates for six ¹⁵N-labeled substrates: nitrate, nitrite, ammonium, urea, cyanate, and dissolve free amino acids across distinct marine provinces, including the continental shelf of the Mid-and South Atlantic Bights (MAB and SAB), the Slope Sea, and the Gulf Stream, marking the first instance of simultaneously measuring six different N uptake rates in this dynamic region. …

Ice-Marginal Lava Delta In Iceland Found On A Nondescript Shallow Slope: An Unexpected Record Of Ice Thickness Late In Deglacian, Audrey Putnam, Kirsten Siebach, Candice Bedford, Sarah Simpson, Elizabeth Rampe, Joseph Tamborski, Michael Thorpe

OES Faculty Publications

Volcanism increases when glaciers melt because isostatic rebound during deglaciation decreases the pressure on the mantle, which enhances decompression melting. Anthropogenic climate change is now causing ice sheets and valley glaciers to melt around the world and this deglaciation could stimulate volcanic activity and associated hazards in Iceland, Antarctica, Alaska, and Patagonia. However, current model predictions for volcanic activity associated with anthropogenic deglaciation in Iceland are poorly constrained, in part due to uncertainties in past volcanic output over time compared to ice sheet arrangements. Further work specifically characterizing glaciovolcanic and ice-marginal volcanoes in Iceland is needed to reconstruct volcanic output …

Interpreting An Archaean Paleoenvironment Through 3d Imagery Of Microbialites, Cecilia M. Howard, Nathan D. Sheldon, Selena Y. Smith, Nora Noffke

OES Faculty Publications

While stromatolites, and to a lesser extent thrombolites, have been extensively studied in order to unravel Precambrian (>539 Ma) biological evolution, studies of clastic-dominated microbially induced sedimentary structures (MISS) are relatively scarce. The lack of a consolidated record of clastic microbialites creates questions about how much (and what) information on depositional and taphonomic settings can be gleaned from these fossils. We used μCT scanning, a non-destructive X-ray-based 3D imaging method, to reconstruct morphologies of ancient MISS and mat textures in two previously described coastal Archaean samples from the ~3.48 Ga Dresser Formation, Pilbara, Western Australia. The aim of this …