Physical Sciences and Mathematics Commons^™

Observations And Light Curve Analysis Of Transiting Extra-Solar Planets, Clark M. Holcomb

Electronic Theses and Dissertations

The purpose of this research was to perform the procedures to study transiting exoplanets in their entirety, from the data collection process to determining physical characteristics and orbital properties. The research was conducted with two telescopes of different sizes (16” and 12”) at multiple sites in order to refine the detection process. Both Maxim DL and Mira Pro x64 software were used to process the resulting images. The PHOEBE program was used to model the data to determine the properties of the exoplanets, which were then compared to the results obtained by other astronomers. The data collection process as well …

Single Particle Tracking: Analysis Techniques For Live Cell Nanoscopy., Peter K. Relich

Physics & Astronomy ETDs

Single molecule experiments are a set of experiments designed specifically to study the properties of individual molecules. It has only been in the last three decades where single molecule experiments have been applied to the life sciences; where they have been successfully implemented in systems biology for probing the behaviors of sub-cellular mechanisms. The advent and growth of super-resolution techniques in single molecule experiments has made the fundamental behaviors of light and the associated nano-probes a necessary concern among life scientists wishing to advance the state of human knowledge in biology. This dissertation disseminates some of the practices learned in …

How Shape Of Simulated Graphene Sheets Affects Debye Scattering Patterns, Lindsay Lesh

Honors Projects

This research is about understanding the structure of a subset of graphitic stardust found in primitive meteorites (e.g. the Murchison meteorite). The carbon grains of interest exhibit a core-rim structure, where the core – with a density less than that of the graphitic rim – comprises the majority of the grain. Previous studies have shown that the cores are comprised primarily of unlayered graphene, and it has been hypothesized that the cores are the result of the rapid freezing (quenching) of a liquid carbon droplet. Electron diffraction is sensitive to small differences in crystal structure and simulated electron diffraction powder …

Calculating And Analyzing Night Sky Brightness For The Commerce/Greenville, Texas Area, Rebecca Bosmans

Honors Theses

No abstract provided.

Memory Effects In Brownian Motion, Random Walks Under Confining Potentials, And Relaxation Of Quantum Systems, Matthew Chase

Physics & Astronomy ETDs

This dissertation is a report on a number of distinct topics in the field of non-equilibrium statistical mechanics including the evolution of classical as well as quantum systems.

The evolution of an object that is described by the Ornstein-Uhlenbeck process generalized through a time-nonlocal attraction is considered. The time-nonlocality is taken to be represented in the Langevin description through the presence of memory. Analysis of the Langevin equation is performed for algebraic and delay-type memories. An equivalent \emph{bona-fide} Fokker-Planck equation is constructed.

A random walker subjected to a non-standard confining potential, taken to be a piece-wise linear function, is analyzed. …

Elasticity Of Cylindrical Black Holes, Conrad Pearson

Physics

Black holes are regions of strong gravity, and are often regarded as behaving like drops of fluid. When this line of thought is applied to cylindrical black holes (black cylinders), a mapping can be made between known instabilities for black cylinders and ordinary fluid cylinders. However, this known correlation is increasingly less accurate for lower spatial dimensions, and I seek to correct this discrepancy in this thesis. By considering soft solids instead of pure fluids, elastic energy can be included, which brings us closer to a direct comparison. In improving this mapping, it becomes possible to better understand the behavior …

Effects Of Mars Regolith Analogs, Uvc Radiation, Temperature, Pressure, And Ph On The Growth And Survivability Of Methanogenic Archaea And Stable Carbon Isotope Fractionation: Implications For Surface And Subsurface Life On Mars, Navita Sinha

Graduate Theses and Dissertations

Mars is one of the suitable bodies in our solar system that can accommodate extraterrestrial life. The detection of plumes of methane in the Martian atmosphere, geochemical evidence, indication of flow of intermittent liquid water on the Martian surface, and geomorphologies of Mars have bolstered the plausibility of finding extant or evidence of extinct life on its surface and/or subsurface. However, contemporary Mars has been considered as an inhospitable planet for several reasons, such as low atmospheric surface pressure, low surface temperature, and intense DNA damaging radiation. Despite the hostile conditions of Mars, a few strains of methanogenic archaea have …

Development Of A Pluto Chamber For Surface Simulations, Zachary Michael Mcmahon

Graduate Theses and Dissertations

In light of the exciting new discoveries being made by the New Horizons team, more data on Pluto is available than ever before. However, with the increase in recovered data, there is now a need for laboratory data to interpret it. Laboratory simulation of these conditions and subsequent testing of materials and samples therein is now possible and necessary to understand what has been observed. To do these simulations, a vessel that can achieve low temperatures and high vacuum is required. The scope of this work presented here was to design, build, and test a chamber that could perform these …

Growth Of Methanogens In The Presence Of Perchlorate Salts: A Study For Possible Life On Mars, John Cale

Biological Sciences Undergraduate Honors Theses

The Phoenix Lander collected soil samples from Mars, and it detected perchlorate salts in its analysis [1]. As oxidizing agents, perchlorates pose a threat to the hypothesis that there may be microbial life on Mars. Since Mars is very dry, perchlorate may continue to accumulate in the soil. If anaerobic methanogens inhabit Mars, then they must be able to grow in the presence of perchlorate salts. There were four species of methanogens tested in this project. The methanogens were first exposed to small concentrations of calcium perchlorate, and then they were gradually tested at higher concentrations. Growth was measured by …

Cryogenic Viscous Liquids On Icy Moons, Danielle Neighbour

Civil Engineering Undergraduate Honors Theses

The study of cryogenically viscous liquids such as methane and ethane offers critical insight into the behavior of fluids on icy moons such as Saturn’s moon Titan. Shrouded by a hazy hydrocarbon shield, Titan’s significant nitrogen atmosphere of 1.5 bar, methane-driven hydrological cycle, and lakes and rivers are vaguely similar to our Earthly home. The European-created Huygens probe, carried by the Cassini spacecraft, arrived on Titan’s surface in January 2005 [1]. Upon landing, Huygens photographed its landing site, as seen in Figure 1. The photo depicts rock like objects, thought to be comprised of water ice sitting in a dry …

Extending The Reach Of Directional Dark Matter Experiments Through Novel Detector Technologies, Nguyen S. Phan

Physics & Astronomy ETDs

Dark matter is believed to comprise over 80% of the matter in the Universe. Its composition could be in the form of weakly interacting massive particles (WIMPs), which are predicted by extensions of the Standard Model, namely supersymmetric theories. Even though hints of its existence were detected in astronomical observations over eighty years ago, its detection through means other than the gravitational influence on observable luminous matter still eludes us.

Currently, there are many ongoing direct detection experiments, that aim to measure the signals left by the elastic scattering of WIMPs with nuclei in the detector target material. The detection …

The Cosmic Web, And The Role Of Environment In Galaxy Evolution, Ryan Cybulski

Doctoral Dissertations

The Universe, on extra-galactic scales, is composed of a vast network of structures dubbed the “cosmic web”. One of the most fundamental discoveries about the evolution of galaxies is that their properties have a dependence on their location relative to this cosmic web (i.e., their environment). However, detailed studies of the environmental dependence on galaxy evolution have been extremely challenging due to the inherent complexity of the structures on the largest scales, a plethora of techniques being used to try to map the cosmic web, and other confounding factors, such as the masses of galaxies, that also affect their evolution. …

Probing Dark Matter-Neutrino Connection Via Indirect Detection Experiments, Bradley Knockel

Physics & Astronomy ETDs

Various evidence reveals that dark matter is a primary component of this universe. The amount of dark matter is known, but its identity is a mystery. To determine its properties, efforts to detect and produce dark matter are underway. Dark matter annihilations throughout the galaxy may produce photons, neutrinos, and cosmic rays. Neutrino and photon detectors may then indirectly detect dark matter by detecting these annihilation products. The annihilation rate, dark matter mass, and dark matter scattering rate off of matter affect the signals received at Earth. These signals can therefore probe the identity of dark matter, especially if dark …

High Power Optically Pumped Semiconductor Lasers For Sodium Guidestar Applications, Shawn W. Hackett

Optical Science and Engineering ETDs

Optically pumped semiconductor lasers (OPSLs) are shown to provide a much more compact and less expensive source for illumination of the sodium layer of the mesosphere for use as a sodium laser guidestar via single and two photon excitation schemes. This represents a revolution in laser guidestar technology as the cost, size, and power requirements for a laser guidestar system are shown to have been decreased by an order of magnitude with guidestar performance shown to be similar to previous sources. Sodium laser guidestar sources for broadband simultaneous illumination of multiple lines are developed and simulated. Simulations are then compared …

The Geometry And Density Of B-Emission Star Disks From Statistical Analysis And Numerical Simulations, Isabelle H. Cyr

Electronic Thesis and Dissertation Repository

This thesis is divided into 3 investigations. First we present a novel method to estimate the opening angles of Be star disks from interferometric axis ratio measurements, using Bayesian statistics and Monte Carlo techniques. A large set of theoretical axis ratios generated from disk models were compared to observational samples to determine which distribution best reproduces the observations. We find that the observed axis ratio distributions in the K-, H-, and N-band can best be explained by the presence of thin disks while measurements over the H$\alpha$ line point toward slightly thicker disks. Second, using a smoothed particle hydrodynamics (SPH) …

The Circumstellar Environments Of B-Emission Stars By Optical Interferometry, Bethany Grzenia

Electronic Thesis and Dissertation Repository

A series of B-emission (Be) stars was observed interferometrically and numerically modelled to be consistent with the observations. Uniform geometrical disks were used to make first-order inferences about the configuration of the disk systems’ extended structures and their extent on the sky. Later, the Bedisk-Beray-2dDFTpipeline was used to make sophisticated non-local thermodynamic equilibrium (LTE) calculations of the conditions within the disks. In the first instance, sixteen stars were observed in the near-infrared (K-band, 2.2 micron) with the Palomar Testbed Interferometer (PTI). The Bedisk portion of the pipeline was used to model disk temperature and density structures for B0, B2, B5 …

Fundamental Parameters Of The Lowest Mass Stars To The Highest Mass Planets, Joseph C. Filippazzo

Dissertations, Theses, and Capstone Projects

The physical and atmospheric properties of ultracool dwarfs are deeply entangled due to the degenerate effects of mass, age, metallicity, clouds and dust, activity, rotation, and possibly formation mechanism on their observed properties. Accurate fundamental parameters for a wide range of substellar objects are crucial to testing stellar and planetary formation theories. To determine these quantities, we construct flux-calibrated spectral energy distributions (SEDs) for 234 M, L, T, and Y dwarfs and calculate bolometric luminosity (L_bol), effective temperature (T_eff), mass, surface gravity, radius, spectral indexes, synthetic photometry, and bolometric corrections (BCs) for each object. We use …

Comprehensive Mass Balance Isotope Schematics For Determining The Provenance Of The Moon Forming Impactor., John C. Wolbeck

Dissertations, Theses, and Capstone Projects

The goal of this research was to identify areas where deviations from the canonic Moon forming impact scenario (an impactor approximately 12% of the mass of the Earth merging with 100% accretion efficiency with a proto-Earth each of which has a differentiated homologous anatomy of 30% iron and 70% silicates) may greatly reduce the efficacy of the impact mass balance analytics used to determine the provenance of the impactor based on isotope data from terrestrial and lunar samples and physical data from high resolution SPH computer simulations.

Modeling the giant Moon forming impact is complicated by a lack of knowledge …

Formation And Past Evolution Of The Meteoroid Complex Of Comet 96p/Machholz, Abedin Yusein Abedin

Electronic Thesis and Dissertation Repository

The past dynamical evolution of the meteoroid streams associated with comet 96P/Machholz is investigated. The goal is to obtain a coherent picture of the past capture of this large comet into a short period orbit, and its subsequent breakup hierarchy. In particular, the aim is to constrain the earliest epoch that this large first precursor started to supply meteoroids into the interplanetary space. The fragments and meteoroid streams of that past cometary decay constitute a wide multiplex of interplanetary bodies, knows as the 96P/Machholz complex. The largest presently surviving fragment is comet 96P/Machholz, followed by a large amount of debris …

Emplacement Of The Foy, Hess And Pele Offset Dykes At The Sudbury Impact Structure, Canada, Eric A. Pilles

Electronic Thesis and Dissertation Repository

The 1.85 Ga Sudbury impact structure is the remnant of what is generally considered to have been an ~150–200 km diameter impact basin in central Ontario, Canada. The so-called Offset Dykes are impact melt dykes that are found concentrically around – and extending radially outward from – the Sudbury Igneous Complex (SIC), a ~3 km thick differentiated impact melt sheet. The dykes are typically composed of two main phases of granodiorite: an inclusion- and sulfide-rich granodiorite in the centre of the dyke, and an inclusion- and sulfide-poor granodiorite along the margins of the dyke. This study uses a combination of …

Dicke’S Superradiance In Astrophysics, Fereshteh Rajabi

Electronic Thesis and Dissertation Repository

It is generally assumed that in the interstellar medium much of the emission emanating from atomic and molecular transitions within a radiating gas happen independently for each atom or molecule, but as was pointed out by R. H. Dicke in a seminal paper several decades ago this assumption does not apply in all conditions. As will be discussed in this thesis, and following Dicke’s original analysis, closely packed atoms/molecules can interact with their common electromagnetic field and radiate coherently through an effect he named superradiance. Superradiance is a cooperative quantum mechanical phenomenon characterized by high intensity, spatially compact, burst-like features …

Energy Quantity Estimation In Radiated Acoustic Fields, Eric B. Whiting

Theses and Dissertations

Energy quantities, which are calculated from pressure and particle velocity, yield a great deal of information about acoustic fields. Errors in pressure or particle velocity estimation lead to bias errors the estimation of energy quantities. The bias errors arise from different probe configurations and processing methods. Two processing methods are examined: the traditional method and the recently developed Phase and Amplitude Gradient Estimation (PAGE) method. These two methods are compared to investigate how each estimates pressure and particle velocity and the subsequent bias errors in a plane wave, standing wave, and spherical spreading wave field. Analytical expressions are derived for …

Increasing The Computational Efficiency Of Combinatoric Searches, Wiley Spencer Morgan

Theses and Dissertations

A new algorithm for the enumeration of derivative superstructures of a crystal is presented. The algorithm will help increase the efficiency of computational material design methods such as cluster expansion by increasing the size and diversity of the types of systems that can be modeled. Modeling potential alloys requires the exploration of all possible configurations of atoms. Additionally, modeling the thermal properties of materials requires knowledge of the possible ways of displacing the atoms. One solution to finding all symmetrically unique configurations and displacements is to generate the complete list of possible configurations and remove those that are symmetrically equivalent. …

Resting-State Connectivity Dynamics In The Human Brain Using High-Speed Fmri, Kishore Vakamudi

Physics & Astronomy ETDs

Resting-state fMRI using seed-based connectivity analysis (SCA) typically involves regression of the confounding signals resulting from movement and physiological noise sources. This not only adds additional complexity to the analysis but may also introduce possible regression bias. We recently introduced a computationally efficient real-time SCA approach without confound regression, which employs sliding-window correlation analysis with running mean and standard deviation (meta-statistics). The present study characterizes the confound tolerance of this windowed seed-based connectivity analysis (wSCA), which combines efficient decorrelation of confounding signal events with high-pass filter characteristics that reduce sensitivity to drifts. The confound suppression and the strength of resting-state …

Similarity, Adequacy, And Purpose: Understanding The Success Of Scientific Models, Melissa Jacquart

Electronic Thesis and Dissertation Repository

A central component to scientific practice is the construction and use of scientific models. Scientists believe that the success of a model justifies making claims that go beyond the model itself. However, philosophical analysis of models suggests that drawing inferences about the world from successful models is more complex. In this dissertation I develop a framework that can help disentangle the related strands of evaluation of model success, model extendibility, and the ability to draw ampliative inferences about the world from models.

I present and critically assess two leading accounts of model assessment, arguing that neither is sufficient to provide …

The Spectral Variability Of Astronomical Pahs, Matthew Shannon

Electronic Thesis and Dissertation Repository

Polycyclic aromatic hydrocarbons (PAHs) are highly abundant molecules found throughout the universe. Illuminated by ultraviolet photons, they can emit up to 10% of the total power output of star-forming galaxies and are involved in many important physical and chemical processes (e.g., gas heating). They produce prominent emission bands between 3-20 μm which vary strongly in intensity and spectral profile. The origins of these variations are not fully understood, which limits the use of PAHs as (ubiquitous) diagnostic tracers of physical conditions. To characterize their variability, we studied the relative intensities and profiles of the 10-20 μm PAH bands in a …

What Governs Star Formation In Galaxies? A Modern Statistical Approach, Sahar Rahmani

Electronic Thesis and Dissertation Repository

Understanding the process of star formation is one of the key steps in understanding the formation and evolution of galaxies. In this thesis, I address the empirical star formation laws, and study the properties of galaxies that can affect the star formation rate.

The Andromeda galaxy (M31) is the nearest large spiral galaxy, and Therefore, high resolution images of this galaxy are available. These images provide data from various regions with different physical properties. Star formation rate and gas mass surface densities of M31have been measured using three different methods, and have been used to compare different star formation laws …

Modeling The Mass Function Of Stellar Clusters Using The Modified Lognormal Power-Law Probability Distribution Function, Deepakshi Madaan

Electronic Thesis and Dissertation Repository

We use the Modified Lognormal Power-law (MLP) probability distribution function to model the behaviour of the mass function (MF) of young and populous stellar populations in different environments. We begin by modeling the MF of NGC1711, a simple stellar population (SSP) in the Large Magellanic Cloud as a pilot case. We then use model selection criterion to differentiate between candidate models. Using the MLP we find that the stellar catalogue of NGC1711 follows a pure power-law behaviour below the completeness limit with the slope α = 2.75 for dN/dlnm ∝ m^(−α+1) in the mass range 0.89 M⊙ to 7.75 M⊙. …

Flickering Analysis Of Ch Cygni Using Kepler Data, Thomas Holden Dingus

Undergraduate Honors Theses

Utilizing data from the Kepler Mission, we analyze a flickering phenomenon in the symbiotic variable star CH Cygni. We perform a spline interpolation of an averaged lightcurve and subtract the spline to acquire residual data. This allows us to analyze the deviations that are not caused by the Red Giant’s semi-regular periodic variations. We then histogram the residuals and perform moment calculations for variance, skewness, and kurtosis for the purpose of determining the nature of the flickering. Our analysis has shown that we see a much smaller scale flickering than observed in the previous literature. Our flickering scale is on …

Surface Plasmon Modes In Toroidal Nanostructures And Applications, Marouane Salhi

Doctoral Dissertations

A special interest in Plasmon mode resonance in toroidal nano-particles where a full and comprehensive analytical investigation is presented for different toroidal nano-structure within the quasi-static approximation. Then the optical response of gold nanorings and the associated near-field mapping when exposed to a broadband electromagnetic wave were obtained by the implementation of numerical methods to solve for the transient response. The numerical and analytical investigation lead to the design of an optical nano-trapping system and the identification of strong coupling interaction between toroidal plasmons and J-aggregate dye molecules a promising component in the design of novel optoelectronic material.