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A Computational Investigation Of Wood Selection For Acoustic Guitar, Jonah Osterhus 2024 Liberty University

A Computational Investigation Of Wood Selection For Acoustic Guitar, Jonah Osterhus

Senior Honors Theses

The acoustic guitar is a stringed instrument, often made of wood, that transduces vibrational energy of steel strings into coupled vibrations of the wood and acoustic pressure waves in the air. Variations in wood selection and instrument geometry have been shown to affect the timbre of the acoustic guitar. Computational methods were utilized to investigate the impact of material properties on acoustic performance. Sitka spruce was deemed the most suitable wood for guitar soundboards due to its acoustic characteristics, strength, and uniform aesthetic. Mahogany was deemed to be the best wood for the back and sides of the guitar body …


Effects Of Post-Deposition Annealing On Room Temperature Deposited Zinc Oxide, Ishan Rayen 2024 Macalester College

Effects Of Post-Deposition Annealing On Room Temperature Deposited Zinc Oxide, Ishan Rayen

Macalester Journal of Physics and Astronomy

This study focuses on thin film deposition of ZnO onto a glass slide using magnetron sputtering. The focus of the study is to understand the effects of post-deposition annealing temperatures. The goal is to optimize crystal quality, conductivity, and transparency. The results attempt to answer the effects of room temperature deposition and changes in film properties once annealed. Annealing temperatures ranged from 100°C to 400°C with an annealing time of 30 minutes. This found an ideal temperature of 250°C for post-deposition annealing, resulting in approximately 3.86 times more conductivity with little to no decrease in transparency. However crystal quality did …


Time Resolved X-Ray Spectroscopy Of Highly Charged Ar, Nd, And Pr, Timothy Burke 2024 Clemson University

Time Resolved X-Ray Spectroscopy Of Highly Charged Ar, Nd, And Pr, Timothy Burke

All Dissertations

Highly Charged Ions (HCIs) may be considered ideal mini-laboratory in which one can study the physics of matter and light in an environment of high internal electric field that can not be recreated with standard lab equipment. The remaining electron(s) exist in the extremely large electric field of the nucleus and therefore measurements of electronic transitions in these systems provide stringent tests of our understanding of physics in extreme conditions. Quantum electrodynamics (QED) despite being a powerful theory exhibits large discrepancies for systems under extreme conditions. The work here investigates the atomic properties within non-Maxwellian plasmas. The HCI plasmas studied …


Experimental Analyses Of Emission Lines In The Uv/Vis/Nir Range For Astrophysically-Important Elements: From The Iron Group To R-Process Elements, Brynna Neff 2024 Clemson University

Experimental Analyses Of Emission Lines In The Uv/Vis/Nir Range For Astrophysically-Important Elements: From The Iron Group To R-Process Elements, Brynna Neff

All Dissertations

Analysis of astrophysical phenomena requires an understanding of the electronic

structure and transition probabilities of the elements present in that environment,

yet there are still many charge states of heavy elements whose electronic

structures and spectroscopic properties are not yet well understood. To address this,

we investigated the spectroscopic properties of three different elements through an

analysis of spectra collected from three different experimental apparatuses.

In order to better understand the spectroscopic properties of Ni I and II, we

analyzed spectra collected from the Compact Toroidal Hybrid (CTH) apparatus at

Auburn University. In this experiment, a nickel sample was inserted …


Understanding The Impact Of Divertor And Main Chamber Ion Fluxes On Divertor Closure In The Diii-D Tokamak, Kirtan M. Davda 2024 University of Tennessee, Knoxville

Understanding The Impact Of Divertor And Main Chamber Ion Fluxes On Divertor Closure In The Diii-D Tokamak, Kirtan M. Davda

Doctoral Dissertations

The diverted tokamak redirects extreme heat and particles to targets, a plasma-facing component designed for such loads. Here, the local fluxes produce strong particle recycling and sputtering. Recycled neutrals can “leak” into the region between the core and wall, the scrape-off-layer (SOL), impacting plasma performance. Increasing divertor closure can reduce leakage by containing neutrals within the divertor. However, there exists a need to quantify divertor baffle restrictions and understand closure directly from empirical data as opposed to indirectly through modeling.

Our study introduces the Geometric Restriction Parameter (GRP) based on simplifying neutral transport to ballistic pathways. Specifically, it considers the …


An Evaluation Of Spectroscopic Databases: Content, Structure, Toolsets, Usability, And Documentation, Joseph William Braker 2024 University of Tennessee, Knoxville

An Evaluation Of Spectroscopic Databases: Content, Structure, Toolsets, Usability, And Documentation, Joseph William Braker

Masters Theses

Spectroscopic databases provide a critical service in the greater field of spectroscopy. Many subdisciplines of spectroscopists use the data contained within, whether calculating theoretical models, evaluating the atmosphere of a planet in the furthest reaches of the galaxy, or monitoring the emission levels of a chemical process. The intention of this research is to seek a deeper level of understanding of spectroscopy and the resources available while providing a comparison of the databases, the content within, and their peripheral tools and features. An experimental effort was derived to utilize existing experimental data from multiple sources and determine which data source …


Implementation Of Python Based High Voltage Tests For Gem Detectors, John Paul Hernandez 2024 Florida Institute of Technology

Implementation Of Python Based High Voltage Tests For Gem Detectors, John Paul Hernandez

Aerospace, Physics, and Space Science Student Publications

The Compact Muon Solenoid, CMS, and other detectors at LHC are in the process of being upgraded for the HL-LHC (High-Luminosity Large Hadron Collider) which will produce more than 5 times the particle interactions than of the current LHC. One upgrade to CMS is the introduction of new GEM detectors (Gaseous Electron Multiplier), GE2/1 and ME0 shown at right are new detectors to CMS and therefore must be tested thoroughly prior to being installed.


Float Like A Butterfly, Sting Like A Bee!, Kobe D. Rome 2024 Fort Hays State

Float Like A Butterfly, Sting Like A Bee!, Kobe D. Rome

SACAD: John Heinrichs Scholarly and Creative Activity Days

By injecting an electron into the empty pie* molecular orbital (LUMO) of Amino Acids in gas phase, we measure the Vertical Attachment Energies (VAEs) for the formation of short-lived anion states of these species using electron transmission spectroscopy (ETS). Our ETS study, a first of its kind to measure the VAE for the simplest of proteins, Glycine-Glycine (Gly-Gly), is currently in progress. Based on our previous measurements for several Amino Acids including Glycine, we expect a common range of attachment energy (1.50 – 2.00 eV) for Gly-Gly.


All-Optical Probes Of Particle-Like Charge Migration Dynamics, Kyle A. Hamer 2024 Louisiana State University

All-Optical Probes Of Particle-Like Charge Migration Dynamics, Kyle A. Hamer

LSU Doctoral Dissertations

Particle-like charge migration (CM) is the coherent, back-and-forth motion of a positively-charged electron hole along the backbone of a molecule following a sudden ionization. CM in small molecules generally occurs on an Angstrom (10-10 m) spatial scale and an attosecond (10-18 s) timescale. I use time-dependent density-functional theory (TDDFT) to simulate CM modes in organic molecules, and to explore all-optical probes of this attosecond electron dynamics using high-harmonic spectroscopy (HHS). By leveraging my results from previous studies of two-center interferences in carbon dichalcogens, in which I separated the harmonic signal into contributions from individual Kohn-Sham orbitals, I first …


Modeling And Numerical Analysis Of The Cholesteric Landau-De Gennes Model, Andrew L. Hicks 2024 Louisiana State University and Agricultural and Mechanical College

Modeling And Numerical Analysis Of The Cholesteric Landau-De Gennes Model, Andrew L. Hicks

LSU Doctoral Dissertations

This thesis gives an analysis of modeling and numerical issues in the Landau-de Gennes (LdG) model of nematic liquid crystals (LCs) with cholesteric effects. We derive various time-step restrictions for a (weighted) $L^2$ gradient flow scheme to be energy decreasing. Furthermore, we prove a mesh size restriction, for finite element discretizations, that is critical to avoid spurious numerical artifacts in discrete minimizers that is not well-known in the LC literature, particularly when simulating cholesteric LCs that exhibit ``twist''. Furthermore, we perform a computational exploration of the model and present several numerical simulations in 3-D, on both slab geometries and spherical …


Advancements In Characterization Of Ancient Potteries From Southeast Asia: A Review Of Analytical Techniques, Chitnarong Sirisathitkul 2024 Division of Physics, School of Science, Walailak University, Nakhon Si Thammarat 80160, Thailand

Advancements In Characterization Of Ancient Potteries From Southeast Asia: A Review Of Analytical Techniques, Chitnarong Sirisathitkul

Makara Journal of Science

Ancient potteries offer valuable information regarding technological advancements, life dynamics, cultural diversity, and trade routes in the past. Earthenware, stoneware, and porcelain from Southeast Asia have been characterized using several analytical techniques, as reviewed in this article. Fluorescent and diffracted X-rays give rise to elemental and phase compositions, respectively. Examination of molecular bonds requires vibrational spectroscopy, which is useful for the identification of organic materials in ancient potteries. With the advent of portable X-ray fluorescence and Raman spectrometry, on-site analysis of archeological ceramics is now possible. For in-depth analysis, synchrotron light sources can provide new insights into artifacts through X-ray …


Size Limits And Fission Channels Of Doubly Charged Noble Gas Clusters, Ianessa Stromberg, Stefan Bergmeister, Lisa Ganner, Fabio Zappa, Paul Scheier, Olof Echt, Elisabeth Gruber 2024 University of Innsbruck

Size Limits And Fission Channels Of Doubly Charged Noble Gas Clusters, Ianessa Stromberg, Stefan Bergmeister, Lisa Ganner, Fabio Zappa, Paul Scheier, Olof Echt, Elisabeth Gruber

Faculty Publications

Small, highly charged liquid droplets are unstable with respect to spontaneous charge separation when their size drops below the Rayleigh limit or, in other words, their fissility parameter X exceeds the value 1. The absence of small doubly charged atomic cluster ions in mass spectra below an element-specific appearance size na has sometimes been attributed to the onset of barrierless fission at X = 1. However, more realistic models suggest that na marks the size below which the rate of fission surpasses that of competing dissociative channels, and the Rayleigh limit of doubly charged van der Waals clusters …


Spectroscopic End Point Detection With An Electron Beam Evaporator, Ryan McGraw 2024 Portland State University

Spectroscopic End Point Detection With An Electron Beam Evaporator, Ryan Mcgraw

University Honors Theses

Spectroscopic end point detection is a common tool used for measuring slope changes in wavelength intensity. Using algorithms able to apply this concept, coatings will be able to be dynamically measured in real time and stopped at the appropriate level to ensure process uniformity. It is currently applied to reductive processes such as etching, where the surface will start to be eaten away, creating a plasma. When the entire amount of a material on a substrate has been eaten away, the plasma will change color as it is beginning to etch a different material. Using a spectrometer, this point where …


Doubly Charged Dimers And Trimers Of Heavy Noble Gases, Gabriel Schöpfer, Stefan Bergmeister, Milan Ončák, Ianessa Stromberg, Masoomeh Mahmoodi-Darian, Paul Scheier, Olof Echt, Elisabeth Gruber 2024 University of Innsbruck

Doubly Charged Dimers And Trimers Of Heavy Noble Gases, Gabriel Schöpfer, Stefan Bergmeister, Milan Ončák, Ianessa Stromberg, Masoomeh Mahmoodi-Darian, Paul Scheier, Olof Echt, Elisabeth Gruber

Faculty Publications

Many doubly charged heteronuclear dimers are metastable or even thermodynamically stable with respect to charge separation. Homonuclear dicationic dimers, however, are more difficult to form. He22+ was the first noble gas dimer predicted to be metastable and, decades later, observed. Ne22+ is the only other dicationic noble gas dimer that has been detected so far. Here, we present a novel approach to form fragile dicationic species, by post-ionization of singly charged ions that are embedded in helium nanodroplets (HNDs). Bare ions are then extracted by colliding the HNDs with helium gas. We detect homonuclear doubly charged …


On The Exact Helium Wave Function Expansion, Ii, An Exponential Modulated Form, Carl W. David 2024 University of Connecticut

On The Exact Helium Wave Function Expansion, Ii, An Exponential Modulated Form, Carl W. David

Chemistry Education Materials

A 11S wave function’s expansion for 2 electron atoms and ions is proposed employing an appropriate exponential factor and Fock’s logarithmic terms. The leading coefficient’s are presented.


Light That Appears To Come From A Source That Does Not Exist, Itamar Stern, Yakov Bloch, Einav Grynszpan, Merav Kahn, Yakir Aharonov, Justin Dressel, Eliahu Cohen, John C. Howell 2024 The Hebrew University of Jerusalem

Light That Appears To Come From A Source That Does Not Exist, Itamar Stern, Yakov Bloch, Einav Grynszpan, Merav Kahn, Yakir Aharonov, Justin Dressel, Eliahu Cohen, John C. Howell

Mathematics, Physics, and Computer Science Faculty Articles and Research

Superoscillatory, band-limited functions oscillate faster than their fastest Fourier component. Superoscillations have been intensively explored recently as they give rise to many out-of-the-spectrum phenomena entailing both fundamental and applied significance. We experimentally demonstrate a form of superoscillations which is manifested by light apparently coming from a source located far away from the actual one. These superoscillations are sensed through sharp transverse shifts in the local wave vector at the minima of a pinhole diffraction pattern. We call this phenomenon “optical ventriloquism.”


Questioning Reality: The Progressive Development Of Modern Physics, Joshua Lancman 2024 Golda Och Academy

Questioning Reality: The Progressive Development Of Modern Physics, Joshua Lancman

STEM for Success Showcase

Humanity has a tendency to divide time. The past is distinct from the present which is entirely separate from the future. In supposedly 20-20 vision history is neatly divided into different sections, distinct eras with sharp lines between them. What is present and in the future is always modern. What is past is something else with another name.

Yet time is not divided so neatly. We know this living through it: years and decades blend into one another in a non-uniform progression. To divide human history into separate eras is a necessary simplification, as it helps to ascribe order onto …


Single-Stage Few-Cycle Pulse Amplification, Sagnik Ghosh, Nathan G. Drouillard, TJ Hammond 2024 Manipal Institute of Technology, Manipal University

Single-Stage Few-Cycle Pulse Amplification, Sagnik Ghosh, Nathan G. Drouillard, Tj Hammond

Physics Publications

Kerr instability can be exploited to amplify visible, near-infrared, and midinfrared ultrashort pulses. We use the results of Kerr instability amplification theory to inform our simulations amplifying few-cycle pulses. We show that the amplification angle dependence is simplified to the phase-matching condition of four-wave mixing when the intense pump is considered. Seeding with few-cycle pulses near the pump leads to broadband amplification without spatial chirp, while longer pulses undergo compression through amplification. Pumping in the midinfrared leads to multioctave spanning amplified pulses with single-cycle duration not previously predicted. We discuss limitations of the amplification process and optimizing pump and seed …


Compton Scattering Of Mammographic Soft X-Ray Beams By Alkali And Transition Metal Salt Filters Produce X-Ray Interference Zones That May Have Treatment Potential For Localized Cancer Lesions, Subhendra N. Sarkar, Eric Lobel, Sabina Rakhmatova, Derbie Desir, Somdat Kissoon, Daler Djuraev, Katie Tam 2024 CUNY New York City College of Technology

Compton Scattering Of Mammographic Soft X-Ray Beams By Alkali And Transition Metal Salt Filters Produce X-Ray Interference Zones That May Have Treatment Potential For Localized Cancer Lesions, Subhendra N. Sarkar, Eric Lobel, Sabina Rakhmatova, Derbie Desir, Somdat Kissoon, Daler Djuraev, Katie Tam

Publications and Research

In breast x-ray imaging scattered radiation adds 50% of harmful radiation dose from anisotropic Compton scattering mechanism. We have been working with double layered inorganic salt materials that can induce Compton scattering to the incident mammographic x ray beams (in 20-30 kVp range) with adequate isotropy (angular control). Typically metal nitrates and alkali halide salt layers are shown here to cause low energy radiation interference zones with high and low photon intensities and local flux heterogeneity in terms of flux covariance. Spatial variation of low energy photon flux creates concentrated and sparse radiation zones that may be used to induce …


Charged Excitons And Trions In The Semiconductor Quantum Dot: Electronic Structure And Effect Of External Fields, Jayden Leonard 2024 Marshall University

Charged Excitons And Trions In The Semiconductor Quantum Dot: Electronic Structure And Effect Of External Fields, Jayden Leonard

Theses, Dissertations and Capstones

In this thesis, we are studying the electronic structures and optical properties of charged excitons and trions (i.e., the exciton-associated quasi-particles in semiconductor materials) in quantum dots which have a three-dimensional confinement configuration. We also consider the effects of an external electric and magnetic field on the charged excitons. Initially theorized in 1958, charged excitons are a fairly new phenomenon in physics in which an exciton (i.e., an electron coupled with an electron hole) is coupled with either another electron or another hole (giving either a ‘negative exciton’ or ‘positive exciton’ accordingly). In the completely confined configuration like the quantum …


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