Physics Commons^™

Investigating The Effects Of Pressure On Fe And Co Intercalated 2h-Tas2 Through First-Principle Calculations, Ronald E. Putnam Jr.

UNF Graduate Theses and Dissertations

Using first-principles methods, we investigate the effects of applied isotropic pressure on the electronic and magnetic properties of intercalated Fe1/3TaS2 and Co1/3TaS2. Fe1/3TaS2 has been shown to be a ferromagnet that undergoes structural and magnetic phase transitions under applied pressure. The magnetic phase transitions are observed to be linked to the structural shift, and a mixture of magnetic phase states is present between 3 GPa and 6 GPa. Co1/3TaS2 was found to be antiferromagnetic, as confirmed by experimental work. One- and two-unit-cell systems of Co1/3TaS2 are analyzed, both showing band splitting that disappears under pressure. The application of pressure forces …

Real-Time Immersive Wildfire Simulation: A Game Engine Approach, Jake Bova

Graduate Student Theses, Dissertations, & Professional Papers

Wildfires are growing in frequency, size, and severity, placing escalating demands on firefighting resources and putting lives, property, and ecosystems at risk. Accurate prediction of fire behavior is critical to suppression planning, evacuation decisions, and firefighter training, yet the operational models that fire managers rely upon face a persistent tradeoff. High-fidelity physics-based models capture fire–atmosphere interactions faithfully but are computationally expensive, often running far slower than real time on CPU hardware, while faster empirical models sacrifice the dynamic coupling between a fire and the wind field it generates. Furthermore, most existing tools produce abstract, two-dimensional outputs that offer limited visual …

Temperature-Dependent Dielectric Function Of Solids From Coupled Oscillators With Radiation Reaction: Application To Atom–Surface Interactions, Tuhin Kanti Das

Doctoral Dissertations

In this dissertation, we propose a uniform functional form of the dielectric function of solids that is applicable over a wide range of frequencies. We apply our model to describe the dielectric function of two technologically important materials: silicon and calcium fluoride. The temperature dependence of their dielectric functions is also described using simple analytic forms. We found that a generalized Sellmeier-type model with complex denominators (“damped oscillators”) does not lead to a satisfactory fit of experimental data for the dielectric function. In contrast, our model, which is analytically only slightly more involved (“complex oscillator strengths”, complex numerators), allows us …

Characterizing A Delay-Programmable Two-Color Femtosecond Light Source For Coherent Control Of Atomic Multi-Photon Ionization Processes, Mason Tanner Toombs

Masters Theses

"In this work a delay-programmable two-color femtosecond laser based on a chirped-seed noncollinear optical parametric amplifier was characterized. This design utilizes a titanium-sapphire crystal oscillator to generate broadband pulses of light spanning approximately 600-1200 nm, with a pulse duration of ~5 fs, repetition rate of 80 MHz, and pulse energy of ~2.5 nJ. An infrared portion of the light, spanning approximately 1020-1060 nm, is split off from the pulse and used to generate a pump beam. By dispersing the remaining seed beam and controlling the relative timing delay between the seed and the pump, tunable frequencies within the seed can …

Investigating A Nanoparticle-Assisted Approach For Localized Strain Engineering In Two-Dimensional Materials, Skye Martichuski

Honors Theses and Capstones

This work investigated a fabrication strategy for inducing localized nanoscale deformation and strain in transferred MoS2 flakes using gold nanoparticle-coated substrates as a potential platform for strain engineering in two-dimensional materials. Substrate type, nanoparticle concentration, drying conditions, cleaning procedures, and flake transfer methods were investigated using optical microscopy and atomic force microscopy (AFM). Au-coated SiO2 substrates produced improved nanoparticle coverage compared to bare SiO2, while passive air drying yielded the most favorable nanoparticle distributions. Salt crystals introduced during passive drying were successfully removed with a gentle deionized water rinse, and a 50% diluted gold nanoparticle suspension provided improved particle spacing …

Mtl_Tx: A Multi-Task Transformer Model For Improved Radiation Time-Series Estimation, Hongfang Zhang, Adam Stavola, Hal Ferguson, Bence Budavari, Hongyi Wu, Chiman Kwan, Jiang Li

Electrical & Computer Engineering Faculty Publications

Controlling radiation doses at potential radioactive facilities is critical to ensuring the safety of both personnel and the public. At the Thomas Jefferson National Accelerator Facility (JLab), multiple sensors are deployed around the three experimental halls to monitor key parameters, including single-beam current, energy levels, current leakage, and radiation values during accelerator operations. In this study, we developed a Multi-task Transformer model, MTL_TX, to accurately estimate radiation doses at sensor locations based on historical data, with the aim of enhancing safety in accelerator facilities and surrounding public areas. To improve estimation accuracy, we integrated two innovative components into the proposed …

Physics-Based Multi-Hazard Fragility Modeling Of Low-Rise Wood-Frame Buildings Under Hurricane-Induced Wind And Surge, Mumtasirun Nahar, Abdullah M. Braik, Mohammad Syed, Maria Koliou, Petros Sideris

Civil & Environmental Engineering Faculty Publications

Coastal buildings are exposed to concurrent hurricane-induced wind and storm surge, yet their vulnerability is commonly assessed using separate single-hazard models that neglect hazard interaction. This study developed a physics-based finite element framework to evaluate the performance of a low-rise light wood-frame building under simultaneous wind and surge-wave loading. A detailed three-dimensional model was constructed using a sub-assembly strategy that explicitly represented framing members, sheathing systems, and critical connections. Structural response was evaluated across a hazard space defined by wind speed, still-water depth, and flow velocity, and component- and system-level fragility functions were derived using Monte Carlo simulation and generalized …

Development Of Thermal Joints For Conduction-Cooling Applications, J. Lewis, G. Ciovati

Mechanical & Aerospace Engineering Faculty Publications

In support of the development of conduction-cooled superconducting radiofrequency (SRF) niobium cavities for use in continuous-wave linear accelerators, an experimental study of thermal contact resistance was performed on bolted joints using high-purity niobium, aluminium, and copper along with Apiezon N grease and indium foil as interfacial materials. The geometry of each joint investigated aims at replicating the design adopted in conduction-cooled SRF cavities currently under development at Jefferson Lab. The materials' thermal conductivity and the joints' thermal resistance were measured in the temperature range of 3.5 - 10 K. The results showed that the low thermal contact resistance of 2-4 …

Predicting Oil Contamination In Water Using Machine Learning On Microbial Compositions, Tong Gao, Isaac Bigcraft, Stephen Techtmann, Issei Nakamura

Michigan Tech Publications

We present a compact and generative machine-learning framework that predicts oil contamination based on microbial community compositions from experimental samples. Our method combines dimensionality reduction with data augmentation and generative modeling to address high-dimensional, non-linear, and sparse microbial data. To reduce the 503-dimensional bacterial composition dataset, we compared three dimensionality reduction techniques: feature importance from random forest, principal component analysis (PCA), and t-distributed stochastic neighbor embedding (t-SNE). Feature importance outperformed PCA and t-SNE, improving predictive performance and identifying microbial species most strongly correlated with oil contamination. To mitigate data scarcity, we augmented the training data using an augmented data neural …

Rydberg Atom Arrays For Electric Field Sensing, James P. Hamilton

Honors College Theses

Rydberg atoms, hydrogen-like atoms that can be excited to states of high principal quantum number that carry correspondingly large electric dipole moments, have become leading candidates for precision electric field sensing. Arrays of such atoms, each trapped in a focused laser beam called an “optical tweezer,” are a particularly promising platform, since the strong dipole-dipole interactions between neighboring atoms provide a resource unavailable in a single-atom sensor. This thesis develops a theoretical and numerical framework for electric field measurement in small Rydberg atom arrays. We begin with a two-level model of a single atom, derive the Hamiltonian and equations of …

An Application Of Molecular Dynamics To Hed Plasma Physics: Point And Group Defect Diffusion In Coulomb Crystals, Levi Webb

Theses and Dissertations

Molecular dynamics (MD) simulations are used to explore the microscopic behaviors of complex systems that cannot be easily studied experimentally. In particular, the microphysics of high energy density (HED) astrophysical plasma environments remain inaccessible by modern experiment---even in laser facilities, these plasmas exist only on short timescales that do not lend easily to investigation. The diffusion of point and group defects through crystallized plasmas in the cores of white dwarfs and neutron star crusts, called Coulomb crystals, has potentially macroscopic implications for the evolution of these bodies. Thus, I employ the widely-used MD code LAMMPS to simulate small Coulomb crystal …

First-Principles And Thermodynamic Modeling Of Hydrogen Storage In Mxenes, Yi Zhi Chu

Dissertations, Master's Theses and Master's Reports

Hydrogen storage is a critical component of the emerging hydrogen economy, playing a central role in enabling the global transition from fossil fuels to a sustainable, green energy system. With advances in materials research, increasing attention has been directed toward the development of promising hydrogen storage materials. Due to their diverse and advantageous physicochemical properties, MXenes have attracted significant interest in this regard. A fundamental understanding of the hydrogen interactions with the MXenes structure is crucial for explaining and predicting their hydrogen storage performance. In this work, first-principles density functional theory (DFT) combined with a revised thermodynamic model is employed …

An Investigation On Downwind Impacts Of The Keweenaw Peninsula On Lake-Effect Snow Events, Thomas M. Pavell

Dissertations, Master's Theses and Master's Reports

Lake-effect snow (LES) produces copious amounts of snow across the Great Lakes region. While mechanisms and impacts are well-understood, they remain difficult to observe and study over Lake Superior and the Upper Peninsula of Michigan due to a large gap in radar coverage and sparse in-situ measurements. The goal of this project aimed to characterize variables present across Lake Superior and counties on and downstream of the Keweenaw Peninsula that contribute to the formation and evolution of lake-effect snowbands. Nine different lake-effect snow events were analyzed in this project, identifying structures and features resulting from upstream passage over the Keweenaw …

First-Principles Investigation Of Quasi-One-Dimensional Van Der Waals Magnets For Advancing Low-Dimensional Spintronics, Alyssa Horne

Dissertations, Master's Theses and Master's Reports

Van der Waals (vdW) magnets have been of great interest for advancing low- dimensional spintronics. A notable example is the quasi-one-dimensional (Q1D) vdW CrSbSe₃, as it is composed of individual one-dimensional units that are held together by the vdW forces. Finding other Q1D vdW magnets that exhibit non-metallic behavior together with long range ferromagnetic ordering is critical in developing next generation spintronics. Here in, using first-principles density functional theory (DFT), we investigate the compositional effects on electronic and magnetic behavior of Cr_1–xMn_xSbSe₃ (x = 0, 0.5, 1). When 50% of Cr is replaced …

Analytical Study Of Transient Mixed Convective Radiative Jeffrey Fluid Flow With Diffusion–Thermo And Chemical Reaction, V. Sathiya, R. Vijayaragavan, B. Rushi Kumar

Mansoura Engineering Journal

This research examines the behavior of unsteady mixed convective radiative Jeffrey fluid flow over a permeable moving plate with a diffusion thermo effect. The study incorporates multiple factors, including aligned magnetic fields, heat generation, radiation, and chemical reactions. The behavior of Jeffrey fluid under these combined conditions is particularly relevant to the design of efficient heat exchangers, MHD generators, and cooling systems for electronic components. A regular perturbation technique was employed to solve the governing equations, yielding distributions for velocity, temperature, and species concentration. These solutions enabled the derivation of expressions for skin friction, Nusselt number, and Sherwood number. Through …

1-D And 2-D Hadamard Transformations For Protein Sequence Analysis, Esraa A. Ahmed, Abed M. Nasr, Marwa A. Abd Elwahaab

Mansoura Engineering Journal

Similarity/dissimilarity studies follow alignment-based or alignment-free methods. Many alignment-free methods involve selecting physicochemical properties. Most previous articles don’t explain their criteria for choosing the properties used. These heuristic approaches have, by definition, undeterministic and unreliable performance. Hence, there is a need for a powerful proxy for similarity/dissimilarity by a deterministic, reliable approach.

In this study, a physicochemical property is selected by a multi-criteria sequential selection process. The amino acids composing any protein sequence are replaced with their values of the chosen property to produce a discrete signal in the time domain.  The one-dimensional discrete Hadamard transforms our signal from the …

Analysis Of Students' Problem-Solving Skills In Work And Energy Based On Gender, Miftahuljannah Muslimin

Jurnal Pendidikan Sains

This study analyzes students’ problem-solving skills on Work and Energy using a quantitative descriptive design, profiling performance across five indicators without causal claims. Participants were 85 students from SMA Negeri 1 Barru, South Sulawesi (30 males, 55 females) who answered five essay items scored on useful description, physics approach, specific application, mathematical procedure, and logical progression. Overall means were 57.73 (females) and 60.73 (males); an independent t-test showed p = .333 > .05 with Cohen’s d = 0.22 (small), indicating no meaningful overall difference. By indicator, ANOVA showed no gender differences (α > .05) except for logical progression (p = .029). …

Information Processing In Quantum Thermodynamic Systems, Shou-I Tang

Graduate Masters Theses

This thesis extends the classical autonomous Hamiltonian framework of information thermodynamics to the quantum regime. In this formulation, a composite system consisting of a principal system, a heat bath, a memory, and a work source is described by fully quantum, time-independent Hamiltonian dynamics. By introducing the quantum speed limit (QSL) for the system and memory subsystems, referred to as the Quantum Thermodynamic Speed Limit (QTSL), I establish a connection between the QTSL and Landauer’s principle. This relationship reveals the fundamental constraints on quantum information processing in terms of dynamics and energy costs during the evolution. Furthermore, I present an interpretation …

Integration Of Islamic Values In Mathematics Learning, Ai Mulya, Surya Faradiba

Jurnal Pendidikan Sains

This study aims to identify the integration of Islamic values in mathematics learning and its contribution to student character development. The method used is a systematic literature study by reviewing relevant accredited scientific articles. The results of the study indicate that the integration of Islamic values is carried out through the preparation of Islamic-context-based mathematics problems, linking concepts to verses of the Qur'an and hadith, the application of ethnomathematics with Islamic cultural nuances, and the introduction of Islamic economic concepts. The dominant values that emerge include honesty, responsibility, discipline, justice, and piety. These findings indicate that the integration of Islamic …

Effect Of Real Quest Outdoor Learning On High School Students Climate Literacy, Siti Aisah, Abdul Hakim, Puardmi Damayanti

Jurnal Pendidikan Sains

This study investigates the influence of the Real Quest Outdoor Learning (ReQOL) model, which encompasses knowledge, attitudes, and behavior, on the climate literacy of high school students. A quasi-experimental design was performed with a non-equivalent control group; thus, a sample consisting of an experimental class (n = 34) and a control class (n = 32) was used. A one-way ANOVA test was used to test the differences between pretest and post-test scores at a 0.05 significance level. The basic knowledge on climate in the experimental group increased significantly (sig < 0.001), while the change in attitudes and behaviors was insignificant (sig = 0.339 and sig = 0.447, respectively). The fact that attitude and behavior did not improve significantly during the experiment can be justified by the existing Adiwiyata programme in schools. These findings indicate that the ReQOL model is a good way to help students understand climate issues better. Adding discovery-based outdoor learning to science classes has the potential to make students more aware of environmental issues and lay the groundwork for the development of responsible behavior. This underscores the scientific contribution and educational importance of the development of climate literacy within the curriculum.

Development Of A High-Doppler Shift Optical Simulator To Test Femtosecond-Level Optical Time-Frequency Transfer, Matthew S. Bigelow, Kyle W. Martin, Nolan Matthews, Benjamin K. Stuhl, Richard Gonzales, Alexandre De Pinho E Braga, John Elgin, Kimberly A. Frey

Space Dynamics Laboratory Publications

We have developed an optical simulator to test real-time optical two-way time–frequency transfer at the femtosecond level capable of simulating relative motion between two linked optical clock nodes up to Mach 1.8 with no moving parts. The technique is enabled by artificially Doppler shifting femtosecond pulses from auxiliary stabilized optical frequency combs. These pulses are exchanged between the nodes to simulate the Doppler shifts observed from a changing optical path length. We can continuously scan the simulated velocity from 14 to 620 m s⁻¹ while simultaneously measuring velocity-dependent clock shifts at much higher velocities than previously recorded. This system …

Geochemical Fingerprinting Of Tanzanian Uranium Deposits: The Insights Of Ree Ratios (La/Ce, Nd/Ce, And Sm/Nd) As A Provenance Tool, Lazaro H. Meza, John W. Kondoro, Iyabo T. Usman, Najat K. Mohammed, Titus A. Msagati, Mwingereza John Kumwenda, Mohamed S. Mazunga

Tanzania Journal of Science

Accurate uranium provenance determination is crucial for nuclear non-proliferation and environmental protection, yet a forensic-level geochemical framework for Tanzanian uranium deposits has been lacking. This study establishes a robust analytical method using forty-five samples from three major deposits (Mkuju, Manyoni, and Bahi), analyzing elemental compositions, particularly Rare Earth Elements (REEs), via ICP-MS, and validating results using Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA). Despite their proximity, the deposits exhibit distinct geochemical signatures as revealed by key REE ratios and anomalies. Mkuju (mean La/Ce 1.17, Nd/Ce 0.62, Sm/Nd 0.56) is characterized by a positive Europium (Eu) anomaly and heavy …

Comparing The Effectiveness Of Eggshell Spectra From Laser-Induced Break-Down Spectroscopy And Near-Infrared Spectroscopy Using Principal Compo-Nent Analysis To Determine The Authenticity Of Organic Eggs, Ahmad Qusthalani, Rara Mitaphonna, Muliadi Ramli, Rajibussalim Rajibussalim, Kurnia Lahna, Nasrullah Zaini, Nasrullah Idris

Makara Journal of Science

This study aimed to explore the potential of modern spectroscopy in the authentication of organic and non-organic chicken eggs using near-infrared spectroscopy (NIRS) and laser-induced breakdown spectroscopy (LIBS) spectra. A total of 175 eggs were analyzed, which were grouped into seven categories based on the source of feed given: 100% organic, 100% non-organic, 75% organic, 75% non-organic, 50% organic, free-range chickens, and eggs obtained from the local traditional market. Each group consisted of 25 eggs. NIRS spectra were recorded in the wavelength range of 350–2500 nm, whereas LIBS spectra were recorded in the range of 200–900 nm. A total of …

(R2164) The Nature Of The Big Bang Singularity In Inhomogeneous Szekeres Cosmological Frameworks, Ahmed M. Al-Haysah, Abdul-Majeed Al-Izeri

Applications and Applied Mathematics: An International Journal (AAM)

Without killing vector fields, the Szekeres metric is an explicit example of an anisotropic and inhomogeneous solution to the Einstein equations. The inhomogeneous Szekeres cosmological models (ISCM) within the Big Bang singularity (BBS) are obtained. This indicates that the Szekeres solution represents a more general class of exact solutions. It is known to exhibit axial symmetry. We investigate a Big Bang theory of the cosmos, which unexpectedly predicts that the universe started at the so-called BBS a finite length of time ago. A growing number of astrophysical researchers are using inhomogeneous extensions of the Friedmann-Lemaitre-Robertson-Walker (FLRW) solution and, by extension, …

Satellite-Mediated Quantum Clock Synchronization: Towards Precise Timing At A Global Scale, Sage B. Ducoing

LSU Doctoral Dissertations

Accurate timekeeping is essential for scientific and technological advancements, particularly in areas of communication, networking, navigation, and high precision measurements. While many methods of time resolution are already established using classical resources, they fail to combine high precision outcomes with large-scale implementations. Additionally, numerous quantum networking architectures using satellite-assisted methods have demonstrated quantum communication on scales exceeding ground-based methods. For these reasons, we propose the use of a time synchronization method by which pairs of highly time-correlated photons are exchanged between clocks on satellites and clocks on Earth, al- lowing users to reconstruct the time offsets between their clocks. This …

Enzyme Active Bath Affects Protein Condensation, Kevin Ching

Dissertations - ALL

The idea that the activity of an active bath can act as an effective temperature and alter system behavior has been theorized and demonstrated for micron-scale systems, but it has not yet been shown for nanoscale systems. Previous studies have suggested that, although passive and active systems can be combined at the nanoscale, activity from the active system typically disrupts and destroys the passive system. In this work, I attempt to create an enzyme-driven active bath to control the liquid–liquid phase separation (LLPS) and condensation of a protein. I find that enzymatic activity enhances phase separation, effectively driving the LLPS …

Machine-Learning Classification Of Gamma-Producing Neutral Current Interactions In Liquid Argon From A Supernova Neutrino Burst, Sierra Thomas

Dissertations - ALL

With five core-collapse supernova candidates within 1 kiloparsec from Earth, extracting information from the neutrino flux will be important to understanding the explosion mechanism of the star (and its composition). The Deep Underground Neutrino Experiment, (DUNE), will be capable of detecting neutrinos from supernovae, primarily from charged-current interactions due to the electron neutrino flavor. However, considering neutrino oscillations in the presence of matter (MSW effects), the muon neutrinos and tau neutrinos will be undetectable if not for the neutral current channel. About 5% of the neutral current interactions will cause the argon nucleus to excite and release a gamma ray …

Developing Best Practice Fabrication For Niobium Superconducting Devices, Jadrien Timothy-Henke Paustian

Dissertations - ALL

Superconducting qubits are a leading platform for scalable quantum computation. This platform offers high gate speeds and can make use of readily scalable complementary metal-oxide semiconductor (CMOS) fabrication techniques. However, superconducting qubits are susceptible to a variety of losses that arise in systems with superconductors, such as due to ubiquitous two-level systems, quasiparticles, and more. Designing fabrication processes to mitigate and manage these loss sources is critical to achieving scalable quantum computation. However, many of these loss sources are set during fabrication processing, of which there can be many different steps, each with its own parameter space. Exploring this space …

Computationally Efficient Methods For Calculation Of Light-Matter Interaction In Large Semiconductor Quantum Dots, Chandler Martin

Dissertations - ALL

Quantum dots are a class of materials in the nanometer scale that have unique optical and electronic properties due to the quantum confinement effect. Traditional electronic structure computational techniques used for calculating these properties fall to scalability issues as the size of the quantum dot increases, or introduce significant errors into the final result. This makes using computational methods to predict new materials, or verify properties of existing materials, challenging to use for experimental applications of quantum dots. This gap between experiment and computation is due to large basis sets, expensive integrals, and storage and manipulation of tensors that grow …

Implementation Of A Carbon-Neutral Pv+Bess System - A Case Study Of Knauf Gypsum Tanzania, Santos Kihwele

Tanzania Journal of Science

This study presents a decarbonization pathway for Tanzania’s industrial sector by integrating a 2.966 MWp solar photovoltaic (PV) system with a 2 MW/8 MWh battery energy storage system (BESS) at KNAUF Gypsum Tanzania. A comprehensive techno- economic analysis was conducted using PVSyst simulations software. The simulation integrated site-specific meteorological data, component specifications and the factory’s electricity load profile to model annual generation patterns, system losses and battery charging and discharging cycles. The model accounted for system degradation to ensure realistic long-term performance projections. The PV+BESS solution reduces the energy-related carbon footprint to 64% and cuts annual energy costs by 65%, …