Physical Sciences and Mathematics Commons^™

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.

A Search For Pulsars And An Exploration Of Dispersion Measure Within The Milky Way Galaxy, Emily Ware

Physics Undergraduate Honors Theses

A pulsar is a rapidly rotating neutron star which emits electromagnetic radiation from its magnetic poles. Upon detection from Earth, these signals have been dispersed in phase due to electron interactions in transit. The extent of this dispersion indicates information about both the distance to and the location of the pulsar, with respect to Earth and the Galactic plane. This project makes use of radio data from the 100m Robert C. Byrd Green Bank Telescope (GBT), presented in the form of prepfold plots assembled by the Pulsar Science Collaboratory (PSC). 1,007 of these plots were analyzed in order to determine …

Biomass Estimation Of Mature Mangrove Trees In The Uae Using Spaceborne Remote Sensing Techniques, Yasmine Ashraf Heikal

Theses

Mangrove forest ecosystems play an essential role in diminishing the effects of climate change caused by the increase in carbon dioxide in the atmosphere. Estimating mangrove forest aboveground biomass (AGB) and hence aboveground carbon (AGC) can assist in decision-making for conservation, sustainable use, and protection of these forests. The goal of this research project was to map the AGB of mangrove forests along the coasts of the United Arab Emirates (UAE) with the aid of Landsat-8-9 satellite imagery data acquired in September 2023. 12 AGB estimation models were developed based on the combination of in situ measurements and Landsat-8-9 derived …

Tilt Instability Of Retrograde Disk Around One Component Of A Binary, Madeline Overton

UNLV Theses, Dissertations, Professional Papers, and Capstones

Be/X-ray binaries are systems containing a massive Be main sequence star and a compact object companion. The Be star contains a disc of material that flows from the Be star, and may interact with the companion. In this work we consider a neutron star companion. With hydrodynamic simulations, we show that a coplanar disc around one component of a binary can be unstable to global tilting when the disc orbits in a retrograde direction relative to the binary. The disc experiences the largest inclination growth relative to the binary orbit in the outermost radii of the disc, closest to the …

Local Map Of The Interstellar Fuv Field, David Lomeli

Open Access Theses & Dissertations

The strength of the far-ultraviolet field is an important parameter in determining the chemistry that takes place in star-forming regions. FUV radiation is produced by bright stars in the galaxy and absorbed by interstellar dust. By using newly available maps of the dust distribution, in conjunction with catalogs of stellar positions and spectra, we created a local map of the FUV field ranging from 6-13.6 eV. We find a value of 6.57*10^-14 erg/cm^3 at the location of the Sun. This value, alongside its spectra, follow previous measurements and estimates of the FUV field at the Sun. We further study the …

Modeling The Spatiotemporal Variations Of The Magnetic Field In Active Regions On The Sun Using Deep Neural Networks, Godwill Asare Mensah Mensah

Open Access Theses & Dissertations

Solar active regions are areas on the Sun's surface that have especially strong magnetic fields. Active regions are usually linked to a number of phenomena that can have serious detrimental consequences on technology and, in turn, human life. Examples of these phenomena include solar flares and coronal mass ejections, or CMEs. The precise predictionof solar flares and coronal mass ejections is still an open problem since the fundamental processes underpinning the formation and development of active regions are still not well understood. One key area of research at the intersection of solar physics and artificial intelligence is deriving insights from …

Survival Of Methanogens Desiccated On Mars Soil Simulants: Implications For Life On Mars, Lanee Knight

Biological Sciences Undergraduate Honors Theses

Because of Mars’s chemical features, it can be studied in the search for life and is a significant figure in the study of astrobiology (McKay, 2010). Dr. Kral’s laboratory studies methanogens, microorganisms in the domain Archaea, as possible life forms on Mars. Since some methanogens can withstand harsh environmental conditions and emit methane as a waste product, the growth of these microorganisms can be used as an indicator of potential life in the Mars subsurface (Kral et al., 1998). In this research, four methanogens, Methanothermobacter wolfeii, Methanobacterium formicicum, Methanosarcina barkeri, and Methanococcus maripaludi were desiccated in the …

Rapid Parameter Estimation Of Compact Binary Coalescences With Gravitational Waves, Caitlin Rose

Theses and Dissertations

In the age of multi-messenger astrophysics, fast, reliable information about gravitational-wave candidates is crucial for electromagnetic follow-up observations. While sky localization tells astronomers where to observe an event, source classification estimates the probability that the event might have an electromagnetic counterpart. Furthermore, astronomers need to have enough time to point their telescopes towards the fading light. Rapid PE is a low-latency parameter estimation scheme which parallelizes Bayesian inference by fixing the intrinsic parameters to a grid, and marginalizing over the extrinsic parameters at each grid point via Monte Carlo sampling. The gravitational-wave search pipelines identify the highest signal-to-noise ratio (SNR) …

The Gravitational Wave Peep: Improved Modeling Of Highly Eccentric Emris For Lisa Signal Confusion Noise, Daniel J. Oliver

Graduate Theses and Dissertations

Scattering events around a massive black hole will occasionally toss a stellar-mass compact object into an orbit around the massive black hole, beginning an extreme mass ratio inspiral. The early stages of such a highly eccentric orbit will not produce detectable gravitational waves as the source will only be in a suitable frequency band briefly when it is close to periapsis during each long-period orbit. This burst of emission, firmly in the millihertz band, is the gravitational wave peep. While a single peep is not likely to be detectable, if we consider an ensemble of such subthreshold sources, spread across …

Unraveling The Physics Of Quasar Jets Using Hst Polarimetry, Devon Clautice

Theses and Dissertations

We present a multiwavelength study of three high-power FR II (quasar) jets -- 3C 273, PKS 0637-752, and 1150+497 -- with an emphasis on new high-quality Hubble Space Telescope (HST) optical polarimetry and Chandra X-ray Observatory imaging. Relativistic jets from active galactic nuclei transport energy and mass from the supermassive black hole’s accretion region out to Megaparsec-scale lobes, with effects that feedback into galaxy formation and cluster energetics. We build on recent work which has called into question our fundamental understanding of FR II jet physics, and suggest that highly-efficient particle acceleration must be taking place in situ …

Better Light Than Never: A New Radiative Mechanism For Observing Binary Black Holes, Paul Rioles

Graduate Masters Theses

Black holes are notoriously elusive, they are impossible to observe directly, and cur- rent methods of extracting information from behind their cosmic camouflage are both limited in number and experimentally difficult. The scope of this investigation is to ex- plore a proposed novel radiative mechanism for active similar mass binary black holes, affording new observational methods to investigate frequency inspirals of BH mergers. The explored mechanism is a result of each BH’s accretion of the surrounding plasma, creating voids that orbit throughout the plasma. The significant results described in this thesis include expressions for the frequency, power radiated per unit …

Dynamical Studies Of Misaligned Circumbinary Disks, Ian C. Rabago

UNLV Theses, Dissertations, Professional Papers, and Capstones

Binary stars are common outcomes of the star formation process, with nearly half of Sun-like stars forming as part of a binary pair. The presence of a second star adds additional complexity and dynamical effects to the planet formation process in the surrounding circumbinary disk. In this work, I investigate the behavior of a circumbinary disk using hydrodynamic modeling, specifically in the case where the disk is misaligned to the binary orbital plane. Around eccentric binaries, highly inclined disks can align themselves perpendicular to the binary orbital plane. These "polar disks'' can produce vortices and spiral arms when the disk …

Understanding Disk Substructures With 3d Self-Consistent Thermodynamics, Shangjia Zhang

UNLV Theses, Dissertations, Professional Papers, and Capstones

Protoplanetary disks are birthplaces of planets. The past decade witnessed a great advance- ment in disk observations by Atacama Large Millimeter Array (ALMA) and extreme adaptive optics (ExAOs). Hundreds of disks have been observed at high angular resolutions and revealed rich substructures (e.g., gaps/rings) at midplane and atmosphere, at least part of which are per- turbed by planets. Deep understanding of disk physics has a great potential to unveil more young planets from substructures and distinguish those that are not caused by planets. I worked on con- straining young planet populations using planet-disk interaction simulations and substructures and self-consistent treatment …

Remnant Polarization And Structural Arrangement In P(Vdf-Trfe) Electrospun Fiber Meshes Affect Osteogenic Differentiation Of Human Mesenchymal Stromal Cells, Bahareh Azimi, Massimiliano Labardi, Mohammad Sajad Sorayani Bafqi, Teresa Macchi, Claudio Ricci, Veronica Carnicelli, Lorenzo Scarpelli, Istiak Hussain, Francesca Matino, Mohammed Uddin

Physics and Astronomy Faculty Publications and Presentations

Highlights

• The type of solvent had noticeable effects on morphology and piezoelectric properties of P(VDF-TrFE) electrospun fibers.

• Using MEK as a solvent and specific environmental conditions led to the obtainment of surface nanopores.

• Uniaxially aligned fibers exhibited higher β phase and mechanical properties than random ones.

• Randomly oriented fibers had higher remnant piezoelectric properties (Vout, d31 piezoelectric coefficient) than aligned ones.

• Human mesenchymal stem cells cultured on randomly oriented fibers showed an accelerated osteogenic differentiation.

Abstract

Many tissues and cells are influenced by mechano-electric stimulation, thus the application of piezoelectric materials has recently received considerable attention in tissue engineering. …

Models Of Low Mass Stars As Physical Labratories, Emily M. Boudreaux

Dartmouth College Ph.D Dissertations

Low mass stars account for approximately 70 percent of the stellar populations (Conroy & Van Dokkum, 2012); yet, due to their small sizes and cool temperatures they account for only a small fraction of the galaxies luminosity function (Laughlin et al., 1997). Moreover, due to the lack of laboratory conditions available to astronomy and astrophysics low mass stars can provide a rare controlled environment for calibrations of numerical models. Consequently, across multiple domains there has been significant interest in these key astronomical objects. In this thesis I present three projects which have further revealed properties of low mass stars and …

Modeling An Extra Planet's Effects On Earth, Emily Simpson

Aerospace, Physics, and Space Science Student Publications

Orbital dynamics play a crucial role in determining the habitability of exoplanets, and many models have been developed to study the dynamical evolution of broader planetary system structure. To further investigate the implications this has regarding planetary habitability, this project simulated the evolution of the Solar System with an additional planet orbiting in place of the Asteroid Belt using the Gravitational Rigid-body InTegrator (GRIT) package. 21 total simulations were run for 100,000 years with varying values for the extra planet’s mass (from 0.01 to 10 Earth masses) and orbital parameters (based on the 4 most massive asteroids in the Asteroid …

A New Effective Gravitational Lensing Approach To Constrain Dark Matter, Birendra Dhanasingham

Physics & Astronomy ETDs

Galaxy-scale strong gravitational lenses offer a unique window into understanding the nature and distribution of dark matter at sub-galactic scales. Beyond the main-lens subhalos, the inclusion of line-of-sight dark matter halos has become essential in lens studies due to their substantial role in perturbing lensed images, making multi-plane lensing a crucial aspect of any lens study. We highlight that these line-of-sight halos appear extended tangentially along the lensing critical line in the effective convergence maps due to the nonlinear nature of multiplane lensing, resulting in a characteristic anisotropic signature in the deflection field. Leveraging tools from large-scale structure analyses, this …

The Black-To-White Hole Transition, Farshid Soltani

Electronic Thesis and Dissertation Repository

Classically, an isolated black hole is a stable gravitational object. If however semiclassical effects are taken into account, an isolated black hole can be shown to slowly radiate its mass away in a process called evaporation. At the end of the evaporation process, when the size of the horizon becomes Planckian, the quantum nature of the gravitational field can no longer be neglected and the dynamics of the horizon is governed by quantum gravity. The main objective of this thesis is the systematic investigation of a tentative scenario for the “end of the life” of a black hole: the black-to-white …

Quantum Computation Using Large Spin Qudits, Sivaprasad Thattupurackal Omanakuttan

Physics & Astronomy ETDs

This dissertation explores quantum computation using qudits encoded into large spins, emphasizing the concept of quantum co-design to harness the unique capabilities of physical platforms for enhanced quantum information processing. First, we delve into the generation of high-fidelity universal gate sets for quantum computation with qudits. Leveraging principles from quantum optimal control, Rydberg physics, and the atomic structure of alkaline-earth atoms, we propose protocols for high-fidelity universal gate sets in the ground state of ⁸⁷Sr with reasonable experimental parameters. Next, we analyze schemes to encode a qubit in the large spin qudits for fault-tolerant quantum computation (FTQC). By comprehending …

Simulating Continuous Gravitational Waves, Ivan Mihael Villalba Moran

SACAD: John Heinrichs Scholarly and Creative Activity Days

Using a table-top Michelson Interferometer to replicate Laser Interferometer Gravitational-Wave Observatory (LIGO) arrangement, we use sound waves to simulate Continuous Gravitational Waves (CWs). Using the NumPy package in Python programming, we recover the frequency of the injected sinusoidal signal using the mathematics of the Fourier Transform. Currently, we are trying to implement the Hidden Markov Model along with the Viterbi Algorithm as a method to detect Wandering Continuous Gravitational Waves.

The Jesuit Tradition Of Astronomy At Holy Cross, Sarah Campbell M.A., M.S.I.S.

Staff publications

This paper summarizes the study of astronomy and related fields as part of the curriculum at the College of the Holy Cross. It briefly profiles four Jesuit priests who were associated with Holy Cross and made significant contributions to the study of astronomy, solar physics and other scientific disciplines. The history of a campus observatory is briefly described as well.

This paper was presented an event sponsored by the Holy Cross Libraries to commemmorate the solar exclipse which occurred April 8. 2024.

A Search For Intermediate-Mass Black Holes In Compact Stellar Systems Through Optical Emissions From Tidal Disruption Events, Richard T. Pomeroy, Mark A. Norris

Physics and Astronomy Faculty Publications and Presentations

Intermediate-mass black holes (IMBH) are expected to exist in globular clusters (GCs) and compact stellar systems (CSS) in general, but none have been conclusively detected. Tidal disruption events (TDEs), where a star is tidally disrupted by the gravitational field of a black hole, have been observed to occur around the supermassive black holes (SMBH) found at the centres of galaxies, and should also arise around IMBHs, especially in the dense stellar cores of CSS's. However, to date none have been observed in such environments. Using data from the Zwicky Transient Facility (ZTF) we search for TDEs associated with CSS, but …

Search For Extreme Mass Ratio Inspirals Using Particle Swarm Optimization And Reduced Dimensionality Likelihoods, Xiao-Bo Zou, Soumya Mohanty, Hong-Gang Luo, Yu-Xiao Liu

Physics and Astronomy Faculty Publications and Presentations

Extreme-mass-ratio inspirals (EMRIs) are significant observational targets for spaceborne gravitational wave detectors, namely, LISA, Taiji, and Tianqin, which involve the inspiral of stellar-mass compact objects into massive black holes (MBHs) with a mass range of approximately 104 ∼107𝑀⊙ . EMRIs are estimated to produce long-lived gravitational wave signals with more than 105 cycles before plunge, making them an ideal laboratory for exploring the strong-gravity properties of the spacetimes around the MBHs, stellar dynamics in galactic nuclei, and properties of the MBHs itself. However, the complexity of the waveform model, which involves the superposition of multiple harmonics, as well as the …

Reflectance Spectroscopy Datasets For The Validation Of Tanager, Kristiana Lapo, Kathleen Hoza, Sammy Theuer, Melissa S. Rice

Geology Faculty Publications

The Three-Axis N-sample Automated Goniometer for Evaluating Reflectance (TANAGER) is a custom goniometer designed to rapidly acquire spectra of natural rock surfaces across the full scattering hemisphere. TANAGER interfaces with a Malvern Panalytical ASD Fieldspec 4 Hi-Res reflectance spectrometer to collect data from 350-2500 nm at a range of incidence, emission and azimuth angles. To validate the accuracy and repeatability of data collected with TANAGER - and to characterize any instrument noise, artifacts or sample heating effects - we collected spectra from three categories of targets: (1) powdered calcium sulfate (anhydrite), (2) naturally weathered basalt surfaces, and (3) color calibration …

Phys 401/801

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 812

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 142

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 211h

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 918

Department of Physics and Astronomy: Syllabi

No abstract provided.

Phys 926

Department of Physics and Astronomy: Syllabi

No abstract provided.