Digital Commons Network^™

Tunable Few- To Many-Cycle Source For High-Order Harmonic Generation And Time-Resolved Spectroscopy, John Beetar

Electronic Theses and Dissertations, 2020-2023

The temporal confinement of laser light pulses to durations approaching the optical period, and the subsequent conversion of these pulses into extreme ultraviolet and x-ray wavelengths through the process of high-order harmonic generation (HHG), has enabled measurement and control of ultrafast processes spanning picosecond to attosecond timescales. Typically achieved by nonlinear compression of multi-cycle pulses in gas-filled hollow-core fibers, compression to single-and even sub-cycle durations is now becoming routine due to the availability of state-of-the-art Ti:sapphire laser amplifiers outputting millijoule level pulses with pulse durations below ten cycles. Even so, reliance on mJ-level Ti:sapphire lasers has in most cases limited …

Space Weathering Simulation Trends On Carbonaceous Chondrites, Andrew Malfavon

Electronic Theses and Dissertations, 2020-2023

Space weathering on primitive asteroids is an ongoing area of research. Primitive asteroids have low geometric albedo (= 0.15) and mostly featureless visible spectra (~0.5 - 0.9 µm) (Campins et al. 2018). Higher albedo S-type asteroids and their corresponding meteorites, ordinary chondrites, have well-characterized space weathering effects. The generally lower albedo primitive asteroids and their less common corresponding meteorites, carbonaceous chondrites, have shown various, sometimes disagreeing results in laboratory simulations. Experiments simulating solar wind exposure on carbonaceous chondrites by Lantz et al. (2017) and Nakamura et al. 2019 showed complex trends on different types of meteorite samples. Thompson et al. …

High-Fidelity Mini-Led And Micro-Led Displays, Yuge Huang

Electronic Theses and Dissertations, 2020-2023

Mini-LED and micro-LED are emerging disruptive display technologies, because they can work as local dimmable backlight to significantly enhance the dynamic range of conventional LCDs, or as sunlight readable emissive displays. However, there are still unresolved issues impairing their display fidelity: 1) motion blur on high-resolution, large-size and high-luminance devices, 2) limited contrast ratio on mini-LED backlit LCD (mLED-LCD), 3) relatively high power consumption, and 4) compromised ambient contrast ratio. This dissertation tackles with each of these issues for achieving high display fidelity. Motion blur is caused by slow liquid crystal response time and image update delays. Low-duty ratio operation …

Multi-Parameter Optical Metrology: Quantum And Classical, Walker Larson

Electronic Theses and Dissertations, 2020-2023

The insights offered by quantum mechanics to the field of optical metrology are many-fold, with non-classical states of light themselves used to make sensors that surpass the sensitivity of sensors using classical states of light. Unfortunately, this advantage, referred to often as "super-sensitivity" is notoriously fragile, and even the slightest experimental imperfections may greatly reduce the efficacy of the non-classical sensors, sometimes completely obviating their advantage. In my thesis I have shown that the performance of an otherwise ideal two-photon interferometer, which exploits entanglement between photons to make super-sensitive measurements of phase, is crippled by the slightest introduction of decoherence …

Midwave Vs Longwave Infrared Search And Track And Aerosol Scattering Target Acquisition Performance, Steven Butrimas

Electronic Theses and Dissertations, 2020-2023

The decision on whether to use a mid wave infrared (MWIR) or long wave infrared (LWIR) sensor for a given task can be a formidable verdict. The scope entails facts about the observable source, the atmospheric interactions, and the sensor parameters within the hardware device. Even when all the individual metrics are known, the combination ultimately determines whether a MWIR or LWIR sensor is more appropriate. Despite the vast number of variables at play, the reduction of inputs through focused studies can provide essential insight into MWIR and LWIR comparisons. This dissertation focuses on the roles of point source target …

Generating Velocity-Dependent Potential In All Partial Waves, Ashwini Kumar Behera, Ujjwal Laha, Jhasaketan Bhoi

Turkish Journal of Physics

Velocity/energy-dependent potential to a parent nonlocal interaction is constructed for all partial waves by Taylor series expansion method and the related s and p-wave phase shifts for N-N and α-N systems are computed by application of modified phase equation. Our phase shifts are in good agreement with standard data.

Tunneling Radiation And Quantum Entropy Of A Massive Gravity Black Hole, Gu Qiang Li, Yi Wen Zhuang

Turkish Journal of Physics

By using the Parikh-Wilczek (PW) quantum tunneling method, the Hawking radiation of black holes in massive gravity is investigated, the emission rate of particles and the black hole entropy are calculated. It is shown that the emission spectrum is not purely thermal, depends on the increment of the black hole entropy, consists with an accurate unitary theory and supports the standpoint of information conservation. Unlike other modified gravities, the entropy of the massive gravity black hole unexpectedly conforms to the area law just as that of Einstein gravity black hole.

Three-Dimensional Measurement Of Electron Temperature And Density In A Split Ring Resonator Microplasma, Neil Laya

Summer Community of Scholars Posters (RCEU and HCR Combined Programs)

No abstract provided.

Newtonian Fractional-Dimension Gravity And Mond, Gabriele U. Varieschi

Physics Faculty Works

This paper introduces a possible alternative model of gravity based on the theory of fractional-dimension spaces and its applications to Newtonian gravity. In particular, Gauss’s law for gravity as well as other fundamental classical laws are extended to a D-dimensional metric space, where D can be a non-integer dimension. We show a possible connection between this Newtonian Fractional-Dimension Gravity (NFDG) and Modified Newtonian Dynamics (MOND), a leading alternative gravity model which accounts for the observed properties of galaxies and other astrophysical structures without requiring the dark matter hypothesis. The MOND acceleration constant $${a_{0}} \simeq 1.2 \times 10^{-10} \text {m}\, \text{s}^{-2}$$can …

Characterization Of A Novel Terahertz Chemical Sensor, Daniel J. Tyree

Browse all Theses and Dissertations

A recently constructed novel analytical tabletop terahertz (THz) chemical sensor capable of detecting a wide range of gases with high sensitivity and specificity was characterized to assess its performance over a range of operational parameters. The sensor was designed with an objective of quantifying composition of exhaled human breath, where target concentrations span part per trillion (ppt) to part per billion (ppb) level of dilutions. The sensor utilizes terahertz rotational spectroscopy of sampled gases for quantification of dilutions. The sensor occupies a volume of ~ 2 ft3 and incorporates a coiled absorption cell, thermal desorption tubes, and all necessary electronic …

Digital Holography Experiments With Degraded Temporal Coherence, Douglas E. Thornton, Davin Mao, Mark F. Spencer, Christopher A. Rice, Glen P. Perram

Faculty Publications

To simulate the effects of multiple-longitudinal modes and rapid fluctuations in center frequency, we use sinusoidal phase modulation and linewidth broadening, respectively. These effects allow us to degrade the temporal coherence of our master-oscillator laser, which we then use to conduct digital holography experiments. In turn, our results show that the coherence efficiency decreases quadratically with fringe visibility and that our measurements agree with our models to within 1.8% for sinusoidal phase modulation and 6.9% for linewidth broadening.

Interpretations Of Bicoherence In Space & Lab Plasma Dynamics, Gregory Allen Riggs

Graduate Theses, Dissertations, and Problem Reports (ETD)

The application of bicoherence analysis to plasma research, particularly in non-linear, coupled-wave regimes, has thus far been significantly belied by poor resolution in time, and/or outright destruction of frequency information. Though the typical power spectrum cloaks the phase-coherency between frequencies, Fourier transforms of higher-order convolutions provide an n-dimensional spectrum which is adept at elucidating n-wave phase coherence. As such, this investigation focuses on the utility of the normalized bispectrum for detection of wave-wave coupling in general, with emphasis on distinct implications within the scope of non-linear plasma physics. Interpretations of bicoherent features are given for time series from …

Characterizing Solar Cells, Katheryn R. Kornegay

Pomona Senior Theses

Perovskite solar cells and organic photovoltaics are both attractive because of their potential flexibility, tunable material properties, and low cost. Though perovskite solar cells have reached efficiencies comparable to conventional silicon solar cells, these have only occurred with lab-scale devices. Organic photovoltaics have much lower operating efficiencies than both perovskite and silicon solar cells, often due to non-uniformities and defects. In this thesis, we use two different techniques to better characterize these two types of solar cells. For perovskite solar cells, we use a drift-diffusion model, to characterize the transition between different doped states in its hole-transport layer, Spiro-OMeTAD, and …

Resource Efficient Design Of Quantum Circuits For Cryptanalysis And Scientific Computing Applications, Edgard Munoz-Coreas

Theses and Dissertations--Electrical and Computer Engineering

Quantum computers offer the potential to extend our abilities to tackle computational problems in fields such as number theory, encryption, search and scientific computation. Up to a superpolynomial speedup has been reported for quantum algorithms in these areas. Motivated by the promise of faster computations, the development of quantum machines has caught the attention of both academics and industry researchers. Quantum machines are now at sizes where implementations of quantum algorithms or their components are now becoming possible. In order to implement quantum algorithms on quantum machines, resource efficient circuits and functional blocks must be designed. In this work, we …

Sparsity And Weak Supervision In Quantum Machine Learning, Seyran Saeedi

Theses and Dissertations

Quantum computing is an interdisciplinary field at the intersection of computer science, mathematics, and physics that studies information processing tasks on a quantum computer. A quantum computer is a device whose operations are governed by the laws of quantum mechanics. As building quantum computers is nearing the era of commercialization and quantum supremacy, it is essential to think of potential applications that we might benefit from. Among many applications of quantum computation, one of the emerging fields is quantum machine learning. We focus on predictive models for binary classification and variants of Support Vector Machines that we expect to be …

Verification Of The Vertical Bubble Flow Experiments, Reginald Jones Ii

Theses and Dissertations

Detailed experimental design to support basic pedagogy of flow regimes – single phase liquid, bubbly, slug, annular, dispersed droplet, and single phase vapor – occurring in flow channels of nuclear reactors has been developed for EGMN 203 - Nuclear Engineering Practicum offering at Virginia Commonwealth University’s Department of Mechanical and Nuclear Engineering. The laboratory instruction will be used to help students forming ideas and understanding flow regimes occurring in nuclear engineering applications. We designed and constructed four water columns to act as surrogates for water channels in a nuclear reactor. Each column was used for a different experiment: salted versus …

Microbial Degradability Of Terrigenous, Marsh-Exported, And Estuarine Colored Dissolved Organic Matter In Long Island Sound, John R. Supino

Dissertations and Theses

The Long Island Sound is one of the world's most urbanized estuaries, polluted from excess nutrients which impact the quality of water through increased biological productivity. Dissolved organic matter (DOM) is a sensitive indicator of anthropogenic pollution and nutrient enrichment in coastal waters as well as an important part of the carbon cycle and serves as a primary food source for aquatic food webs. Additionally, the colored portion of DOM (CDOM) impacts coastal optical properties, ocean color, and light attenuation. High levels of CDOM have been shown to inhibit the growth of phytoplankton and limit photosynthesis, damaging the food chain …

Application Of Optical Trapping To Obtain Single-Source Str Profiles From Forensically Relevant Body Fluid Mixtures With Modified Dna Analysis Workflow, Benjamin J. O'Brien

Master of Science in Forensic Science Directed Research Projects

Current methods of mixture separation in forensic DNA laboratories typically deconvolute the mixture after analysis using statistical analysis or probabilistic genotyping. To save time and effort of labs already backlogged, a method to separate mixtures on a cellular level before analysis needs to be developed. Optical trapping is a method that uses a focused 1064 nm laser to manipulate cells. Previous research has shown that approximately 50 spermatozoa or 15 leukocytes from a liquid sample are required to produce a full STR DNA profile. It was found that the number of spermatozoa required remains constant when the method of sample …

Fabrication And Characterization Of Triple-Cation Perovskite Solar Cells, Passakorn Phiromruk

Chulalongkorn University Theses and Dissertations (Chula ETD)

Presently, triple-cation perovskite solar cells have been appealing due to the outstanding power conversion efficiency (PCE). In this work, the Cs0.03(FAxMA1-x)0.97Pb(IyBr1-y)3 triple-cation perovskite solar cells fabricated by two-step deposition method were studied by varying the content of halide ions (Br and I) and the cation ratios of FA and MA. The results showed that the insertion of Br improved open-circuit voltage due to broader band gap. In case of MAPbI3-based devices, the PCE was also increased with the addition of Br. However, the FAPbI3-based devices were inferior to MAPbI3-based devices resulting from poor quality perovskite layer and the non-photoactive structure …

Characterization Of A Plasma Source Simulating Solar Wind Plasma In A Vacuum Chamber, Blake Anthony Folta

Masters Theses

"The United States has set an aggressive time line to not only return to the Moon, but also to establish a sustained human presence. In the Apollo missions dust was a significant factor, but the duration of those missions was short so dust and surface charging were problems, but they did not pose an immediate threat. For a long-term mission, these problems instead become incredibly detrimental. Because of this, research needs to be conducted to investigate these phenomena so that mitigation techniques can be developed and tested. To this end, this thesis serves to demonstrate the Gas and Plasma Dynamics …

A Search For Resonant And Non-Resonant Di-Higgs Production In The Γγbb Channel Using The Atlas Detector, Tyler James Burch

Graduate Research Theses & Dissertations

This dissertation presents a search for resonant and non-resonant di-Higgs production in the γγb ̄b final state using data from the ATLAS detector at the Large Hadron Collider (LHC). The search is performed on 36.1 fb−1 of data from proton-proton collisions at a center-of-mass energy of √s= 13 TeV collected in 2015 and 2016.

No significant excesses are observed in this search. The non-resonant analysis sets limits on the HH→γγb ̄b cross-section times branching ratio, with an upper observed (expected) limit of 0.73 (0.93) pb. The observed (expected) limits on the Higgs boson trilinear coupling at 95% Confidence Level (CL) …

On The Self-Force Problem Of Point-Like Charged Particles In Classical Electrodynamics, Kevin J. Hamilton

Graduate Research Theses & Dissertations

The problem of a point-like charged particle’s self-interaction force has been along-standing problem in the field of classical electrodynamics. For over a century,physicists have unsuccessfully developed a satisfactory solution until recently. Weexpand on the work done by Gralla et. al. [1] in order to establish a smooth andrelativistically correct formulation of point-like charged particles in motion and shedlight on related problems and applications, particularly the motion of elementary par-ticles with magnetic dipoles through non-uniform static magnetic fields. We conductnumerical simulations in order to quantify the magnitude of the perturbations fromthis self-force due to the new equations of motion relative to …

Development Of An Electron-Beam Halo Diagnostics, Christopher James Marshall

Graduate Research Theses & Dissertations

Electron beam halos defined as the peripheral fraction of the beam that does not contribute to the front end application. Particles located in the halo can cause damage to the particle accelerator and lower the power and quality of the beam. Being able to measure the beam halo could provide insight on the halo-formation mechanism and ultimately will improve the overall performance and quality of the beam. A halo diagnostic was designed, and a prototype built and commissioned. The diagnostics relies on detecting optical radiation by the electron beam and masking its core to enhance the detection of the halo. …

Nonlinear Integrable Optics Beam Dynamics Experimentand Diagnostics, Sebastian Szustkowski

Graduate Research Theses & Dissertations

All present circular particle accelerators are built around linear focusing optics. Unavoidable nonlinear elements appear in accelerators, such as magnetic aberrations and space-charge effects, which are typically corrected using nonlinear magnets. However, these added nonlinearities degrade particle beam stability, and in most cases, the system becomes non-integrable. The Integrable Optics Test Accelerator (IOTA), at Fermi National Accelerator Laboratory (Fermilab), is a test bed to study beam dynamics in integrable lattices for both electron and proton beams, independently.This work presents experimental results of the nonlinear electron beam dynamics behavior in IOTA using an elliptical nonlinear magnet. The elliptical nonlinear magnet allows …

Evaluation Of The Activity Of Zn-65 Isotope And Radiation Dose Delivered To Drosophila Melanogaster, Wasiu Ajani Erinoso

All Graduate Theses, Dissertations, and Other Capstone Projects

Radioactivity is a natural part of our environment. Ionizing radiation from radioactive materials can affect the life cycle of organisms; sometimes increase the rate of transition between cycle leading to the proliferation of cells as seen in some cancer cells or delay the rate of transition between cell cycle. A NaI detector is essential to determine the activity of a radioactive material. To determine the resolution of NaI detector and the efficiency of the geometry used for this experiment, quality control was done for NaI detector using 22Na reference source. The efficiency of the detector was used to verify the …

Quantitative Analysis Of Human Blood Serum Using Vibrational Spectroscopy., Hugh Byrne, Franck Bonnier, Jennifer Mcintyre, Drishya Rajan Parachalil

Articles

Analysis of bodily fluids using vibrational spectroscopy has attracted increasing attention in recent years. In particular, infrared spectroscopic screening of blood products, particularly blood serum, for disease diagnostics has been advanced considerably, attracting commercial interests. However, analyses requiring quantification of endogenous constituents or exogenous agents in blood are less well advanced. Recent advances towards this end are reviewed, focussing on infrared and Raman spectroscopic analyses of human blood serum. The importance of spectroscopic analysis in the native aqueous environment is highlighted, and the relative merits of infrared absorption versus Raman spectroscopy are considered, in this context. It is argued that …

Independent And Simultaneous Control Of Electromagnetic Wave Properties In Self-Collimating Photonic Crystals Using Spatial Variance, Jesus Javier Gutierrez

Open Access Theses & Dissertations

Photonic crystals are engineered periodic structures that provide great control over electromagnetic waves. One of these mechanisms is self-collimation, in which the electromagnetic wave travels through the photonic crystal along an axis of the lattice without diffracting or spreading. This mechanism of self-collimation is a dispersion phenomenon, which is dependent on the unit cell's physical and geometrical characteristics. An algorithm for generating spatially variant lattices (SVL) was developed that can change geometrical properties in photonic crystals as a function of position, like unit cell orientation, fill fraction, symmetry, and others in a manner that is smooth, continuous, and virtually free …

Some Fermi-Lowdin Orbital Self-Interaction Correction Studies On Atomic Systems, Christopher Alexis Ibarra

Open Access Theses & Dissertations

Density Function Theory (DFT) is a popular quantum chemistry calculation method with many appeals but also deficiencies. Many modification and additions to the method have been made over the years, such as self-interaction corrections and new density functional approximations. We review here the theoretical background needed for a basic understanding of quantum chemistry calculations. In addition, we present the quantum chemistry calculation method used in this paper called Fermi-Lowdin Self-Interaction Correction (FLOSIC), including the base code it was implemented on, the Naval Research Laboratory Molecular Orbital Library (NRLMOL) Code, and the resulting modified code simply called FLOSIC. Furthermore, we explore …

Development And Assesment Of Local Scaled Self-Interaction Corrected Density Functional Method With Simple Scaling Factor, Selim Romero

Open Access Theses & Dissertations

The Hohenberg-Kohn-Sham (HKS) density functional theory (DFT) is widely used to compute electronic structures of atoms, molecules, and solids. It is an exact theory in which ground state electron density plays the role of basic variable, same as the wavefunction does in quantum mechanics. The total ground state energy is a functional of electron density. The practical application of HKS DFT require approximation to the exchange-correlation energy functional. Many density functional approximations (DFAs) with various degree of sophistication and complexities have been developed. Depending on the complexity, these functionals include electron density, density gradients, density Laplacian, kinetic energy densities, Hartree-Fock …

Quantum Phases And Phase Transitions In Designer Spin Models, Nisheeta Desai

Theses and Dissertations--Physics and Astronomy

This work focuses on numerical studies of quantum spin systems. These simple models are known to exhibit a variety of phases, some of which have no classical counterpart. Phase transitions between them are driven by quantum fluctuations and the unconventional nature of some such transitions make them a fascinating avenue of study.

Quantum Monte Carlo (QMC) is an indispensable tool in the study of these phases and phase transitions in two and higher dimensions. Nevertheless, we are limited by our inability to simulate models that suffer from the infamous sign problem. While the case of S=1/2 has been studied …