Poster abstracts
Search for states in 23Na above the proton threshold
Diana Carrasco Rojas, Dr. Philip Adsley, Dr. Jorge Lopez, Dr. Matthew Williams
Globular clusters are dense groups of stars which exist near the galactic plane, understanding them sheds light on the history and evolution of galaxies. The presently observed stars contain elements resulting from unknown polluting sites. Identifying those sites requires improved knowledge of nuclear reaction rates. One important rate is the 22Ne(p, ɣ) reaction. There are several unmeasured resonances lying just above the proton threshold for this reaction, and although many studies have been conducted, resonances at Ecm = 68 and 100 keV have not yet been confirmed. For this experiment, a new high-resolution study was performed where a magnetic spectrograph was used to search for states above the proton threshold in 23Na via the 23Na(p,p’)23Na reaction.
Comparing Efficiencies of Isotope 48Calcium Reduction and Recovery Methods
Masiel Velarde, Robert Scott, Jake McLain
The neutron abundant 48Ca isotope has a very low natural occurrence (0.187%). Highly enriched starting material for the production of nuclei in particle accelerators including the Argonne Tandem Linac Accelerator System (ATLAS) is exceptionally valued. We aim to recover enriched 48Ca metal from a mixed CaCO3+Zr sample with unknown quantity of 48Ca. The goal is to carry out two chemical reactions within a standard ECR ion source resistively heated oven. A sample of natural CaC03+Zr with a ratio 1:2 of Ca:Zr by mass was prepared. An oven temperature calibration with power input set values was performed prior to baking the sample, expelling CO2 in a gaseous state and yielding CaO which is then reduced at a slightly higher temperature via reduction with Zr metal to form Ca metal and ZrO2. The Ca metal is evaporated to a small area of a pre-weighed tantalum deposition plate while the ZrO2 remains in the oven crucible. The process was repeated using a resistively heated vapor deposition system to record and compare both Ca metal production efficiencies with a goal of finding a process for use with the enriched 48Ca material. In the vapor deposition system, a CaCO3 and Zr mixture with the same ratio is pressed and placed in a tantalum pinhole boat, which creates a directional vapor of Ca metal under high temperature. The Ca is deposited onto a pre-weighed glass substrate and reweighed after deposition to determine the Ca mass. Calcium metal recovery efficiencies will be reported.
Detection of Faint Donors in Ultracompact Accreting White Dwarf Binaries
Shelby Courreges, Thomas Kupfer
AM CVn systems are mass-transferring compact binaries consisting of a helium-rich white dwarf accretor and a degenerate/semi-degenerate donor having an orbital period of approximately 5-65 min (Solheim 2010). They allow us to study phenomena including stellar evolution and accretion disk physics and they are strong gravitational wave sources (Kupfer et al. 2020). Observationally, the optical data of these sources is dominated by the accreting white dwarf or the accretion disc (e.g., Carter et al. 2013). The donor star has never been observed directly. Due to the donor star’s expected cool temperatures, most of the emission is expected in the far-infrared bands. In this project, we first combined multi-wavelength data from different resources covering the ultraviolet to far infrared searching for an infrared excess from the donor star. Using the photometric data, distance, and reddening, we measured the temperature and radius of the accretor and the donor. To achieve this, a double blackbody was fitted with the first containing wavelengths below 20,000 angstroms to model the accreting white dwarf and the second containing wavelengths above 20,000 angstroms to model the donor star. We discovered a confident infrared excess for 10 systems marking the first detections of the donor star in AM CVn systems. We find a stable temperature and radius for the donor star but a decrease in temperature and radius for an increase in period for the accreting white dwarf. We compare our results with theoretical models as well.
The role of growth models in oncolytic virus therapy
Manya Sharma and Hana M. Dobrovolny
Mathematically programmed cancer cell models can be used by researchers to study the use of oncolytic viruses to treat tumors. With these models, we are able to help predict the viral characteristics needed in order for a virus to effectively kill a tumor. Our approach uses non cancerous cells in relationship to the tumor to determine the speed at which the cells replicate, however there are several models used to describe cancer growth, including the Exponential, Mendelsohn, Logistic, Linear, Surface, Gompertz, and Bertalanffy. We study how the choice of a particular model affects the predicted outcome of treatment.
A Density Dependent Model of Influenza Infection Rate
Hope Sage, Hana M. Dobrovolny
The most common immunological models for analyzing viral infections assume even spatial distribution between virus particles and healthy target cells. However, throughout an infection, the spatial distribution of virus and cells changes. Initially, virus and infected cells are localized so that a target cell in an area with lower virus presence will be less likely to be infected than a cell close to a location of viral production. A density-dependent rate has the potential to improve models that treat cellular infection probability as constant. A Beddington-DeAngelis model was used to understand how density dependent parameters could impact the severity of an influenza infection. Parameter values were varied to understand implications of density constraints. For low density dependence, a steeper increase in number of virus and greater viral peak was predicted. Higher density dependence predicted a longer time to viral load maximum and a greater infection duration. Initial localization of infected cells likely slows the progression of infection. The model demonstrates that accounting for density dependence when analyzing influenza infection severity can result in an altered expectation for viral progression. A density-dependent infection rate may provide a more complete view of the interaction between infected and healthy cells.
How Good are the OMNI Data?
Rushikesh Patil, Pavani Rambachan, Dustin Frost, Espen Fredrick, Pauline Deredger, Dr. Fatemah Bhagheri, Dr. Ramon Lopez
Numerous satellites are used to collect solar wind data, such as THEMIS, ACE, and WIND. These satellites are located at different distances between the Earth and the Sun, and hence these data lag with respect to each other. To investigate the consistency between the THEMIS B and OMNI data, we look for the time when the position of the THEMIS B satellite is very close to the Earth-Sun line. 70 12-hour events from the years 2013-2018 were selected when the THEMIS B satellite was close to the Earth-Sun line. A comprehensive study quantifying the probability of correlation between the two sets of data was carried out using the Z-component of the solar wind interplanetary magnetic field. Preliminary analysis before data gap removal suggests a correlation coefficient above 0.6 occuring only 57.75% of the time, indicating that OMNI data is oftentimes unreliable. A further breakdown of events by OMNI spacecraft ACE and WIND is provided to investigate correlation for each satellite.
A Bohmian Analysis of Energy and Momentum in 1-D Scattering of Relativistic Particles
Abigail Perryman, Kabir Nayaranan
We lay the groundwork for a formal justification of the plane wave assumptions underlying Arthur Compton’s scattering calculation. Using a recent relativistic formulation of Bohmian mechanics, we start by examining the behavior of a single free photon and a single free electron. We offer significant evidence that the electron wave function becomes asymptotically plane wave-like, meaning the particle’s momentum and energy approach fixed values as assumed in Compton’s calculations. We examine the effects the wave function’s initial parameters have on the behavior of particle trajectories, and we explore different ways to visualize trajectories and this asymptotic behavior prior to interaction.
Investigating Student Engagement with a University Telescope Loaner Program
Kendra Hamilton, Dr. Rebekah Purvis
This study involved the development of a pilot telescope loaner program through UNT Astronomy. Through this program, local secondary school teachers can borrow a ten-inch Dobsonian telescope to use in science classes. The potential for continuation of this program and its effect on student engagement was determined through class observations, teacher interviews, and student surveys. Prior research was limited to the use of a remote observatory, which did not produce the desired effects on student engagement. Three teachers used the telescopes in their lessons and reported an increase in engagement as compared to previous years. One of these teachers has requested to borrow the telescope again this spring, meaning the loaner program will continue beyond the completion of this research. Access to high-quality astronomy equipment is uncommon in secondary education, and as such this program has the potential to renew students’ interest in science and increase the number of students choosing to pursue science in higher education.
Syncytia Formation Rate in Variants of SARS-CoV-2
Ava Amidei, Hana Dobrovolny
COVID-19, also known as SARS-Cov-2, has caused a worldwide crisis. SARS-CoV-2 is able to form syncytia cells, which are large multi-nucleated cells. Syncytia formation allows the virus to propagate without leaving the host cell. Currently, not much is known about syncytia cells, including the rate at which they form. Data from a study by Rajah et al. (2021) was used to estimate the rate of synctia formation for each variant of SARS-CoV-2. This includes the Alpha, Beta, D61G, and Wuhan Variants. The rates of syncytia formation were found by using mathematical modeling. This information can better our understanding of syncytia formation.
Spectroscopy Data Found from Carbon Stars VX AND
Cheyenne Valles, Tiffany Jensen
Using data collected from the ISO Spectra as well as from the website SIMBAD, we can form a projected graph of what the data should look like for the carbon star VX AND. The program DUSTY is used to stimulate different variables such as star temperature, dust temperature, chemical composition of dust, size of the dust shell, optical depth into the star dust, etc. This program can be used to output data given certain variables, and the data can be graphed and compared to the ISO and SIMBAD data. Utilizing this data allows us to understand the nature of Star Dust. This data is used to form a deeper understanding of interstellar bodies and how they are created and what they are created from.
Examining the motion of the cool filaments in the center of the Centaurus cluster
Mirielle Caradonna, Shalini Ganguly, Yuan Li
Currently, the source of turbulence in galaxy clusters is undetermined. It is suspected that X-ray bubbles created by black hole feedback pumps energy into the ICM, creating this turbulence. We use data from MUSE to study the structure of cool Hα filaments in the galaxy NGC 4696 (z~ 0.0114), the brightest galaxy in the Centaurus cluster. We study the kinematics of the filaments by examining their velocity structure function (VSF). The VSF on small scales follows a power-law relation, suggesting that the motion of the filaments is turbulent. We also find that the driving scales inferred from the VSF are consistent with the sizes of the X-ray bubbles, suggesting that the turbulent motion is mainly driven by the activities of the supermassive black holes. We also compute the flux correlation functions to gain insights on the ionization mechanism of the filaments.
Formation of Filaments and Nested Surfaces in Microgravity Dusty Plasma
Emerson Gehr, Evdokiya Kostadinova, Marlene Rosenberg, Peter Hartmann, Jorge Carmona-Reyes, Lorin Matthews, Truell Hyde
This research examines the structure and spacing of particles within microgravity dusty plasma clouds using video data from the PlasmaKristall-4 (PK-4) apparatus onboard the International Space Station. The analysis focuses on experiments where gas pressure and current were varied to achieve different plasma conditions, which in turn affect the structural properties of the dust clouds. We analyze videos from a central region of the cloud as well as 3D-scans of the entire cloud. Positions of the particles in each video frame are obtained using particle tracking software, and then used to calculate pair correlation functions that show the probability of finding a particle a certain distance away from another particle. The obtained pair correlations reveal differences in the mean interparticle separation as a function of location in the cloud, gas pressure, and discharge current. We find that particles tend to organize in filamentary structures at the small scales, while forming nested spheroid shells at large scales. While particles within filaments are strongly coupled, suggesting crystalline order, the interaction of particles across filaments is liquid-like. These results provide evidence that the structures observed in the PK-4 have unique liquid crystalline properties. The authors gratefully acknowledge support for this work from the US Department of Energy, Office of Science, Office of Fusion Energy Sciences award number DE-SC-0021334, NSF grant number 1903450, and NVIDIA Corporation’s Applied Research Accelerator Program.
Mathematical Modeling of Oncolytic Virus Therapy
Ela Guo, Hana Dobrovolny
Oncolytic adenoviruses (OAds) present a promising path for cancer treatment, due to their selectivity in infecting and lysing tumor cells and their ability to stimulate immune response%, OAds have potential as a less destructive treatment option. In this study, we use an ordinary differential equation (ODE) model of tumor growth inhibited by oncolytic virus activity to parameterize previous research on the effect of genetically re-engineered OAds in A549 lung cancer tumors in murine models. We find that the data is best fit by a model that accounts for an immune response, and the parameter estimates for the most effective OAds share characteristics, most notably a high infection rate and low viral clearance rate, which may be potential reasons for these viruses’ efficacy in delaying tumor growth. Further studies observing E1A and P19 recombineered viruses in different tumor environments may further illuminate the extent of the effects of these genetic modifications.
High Radio Frequency Pulsar Search of the Galactic Center
Karina Kimani-Stewart, Dr. Maura McLaughlin, William Fiore
We conducted a centrally concentrated search of the Galactic Center for new pulsars at high radio frequencies with data collected from the 100-m Green Bank Telescope. This search accumulated a total of 11 hours of observation time at a central frequency of 9200 MHz. The purpose of using high radio frequencies was to minimize the propagation effects of the interstellar medium. We conducted fourteen pointings to search multiple positions in the Galactic Center, which should have a high density of pulsars, particularly those residing in exotic binary systems. This analysis was done by creating a range of dispersion measure values that would be sensitive to these sources, conducting periodicity searches and single-pulse searches at each specified dispersion measure, then creating diagnostic plots for the periodicity and single-pulse candidates. These diagnostic plots were then evaluated for characteristics resembling those of a pulsar to determine if the candidate could be classified as such. In this search, we also inspected dispersion measure ranges at sufficiently high values that would be sensitive to distant fast radio burst detections.
Analysis and Experiment of air drag on a Sphere.
Nadira Amadou Mahamane, William Slaton
Air drag is a concept that can be analyzed as many small collisions with particles of air. The air drag coefficient is a function of the shape, size, and orientation of the body, as well as the density and viscosity of the air. Theoretical calculation of the drag coefficient of a hemispherical object using basic physics principles is done and the results are compared to experimental calculation in a small vertical wind tunnel. The difference between the real weight of the object and the apparent weight due to air drag allows for experimental determination of the drag coefficient for comparison to theory.
PID Temperature Controller for Microwave Electronics used in Superconducting Quantum Circuits
Hebah Goderya, Theodore Shaw, Shyam Shankar
In circuit quantum electrodynamics, quantum circuits are controlled and probed by generating and reading arbitrary signals, typically at microwave frequencies. Rather than using expensive microwave-frequency digital-analog converters, mixers are used to upconvert signals from low-frequency electronics to microwave frequencies and downconvert signals emitted from the quantum circuit. These analog components are sensitive to temperature fluctuations which affect the optimal performance of the calibrated devices. In this work we build and tune a PID (proportional-integral-derivative) controller to monitor and stabilize the temperature of these room temperature electronics.
Resistivity Anisotropy and Epitaxial Strain of Rare-Earth Nickelates on STO using Pulsed Laser Deposition
Holland Frieling, Angel Martinez, Andrew Yang, Gregorio Ponti1, and John T. Markert
Using x-ray diffraction, electrical resistivity, and atomic force microscopy measurements on uniform thin-film NdNiO3 specimens we intend to probe the effect of varying film thickness on transport properties. In particular, we aim to explore the strain-induced conductivity of epitaxial ultrathin films of NdNiO3 as a future means to make contact to the bottom of a thicker film, and thus access anisotropic resistivity measurements. The samples are prepared by annealing SrTiO3 (STO) substrates (950°C for ~2 hours) and depositing NdNiO3 at 650°C using pulsed laser deposition (PLD) with a KrF excimer laser (λ = 245 nm, pulse duration = 25 ns) and a phase-mixed but stoichiometric target. To optimize oxygen content, a partial pressure of O2 (about 150 mTorr) is introduced to the PLD chamber during deposition.
Wrangling a BOBcat: Building a Brand New Database for Binary Black Holes
Ryan Nowicki, Jessica Sydnor, Sarah Burke-Spolaor
At the center of most every galaxy exists a supermassive black hole (SMBH). As galaxies merge, we expect these black holes to orbit each other before coalescing. However, observing these binaries is difficult, so while there exist many SMBH binary candidates, none have been confirmed. To better organize the extensive data on these candidates, we are building BOBcat — the Black holes Orbiting Black holes Catalog. This catalog will be a fully-referenced, comprehensive database of candidate SMBH binaries. My research has contributed to the core functionality of BOBcat, from populating BOBcat with candidates from the literature to coding critical calculations in order to standardize these candidates before their inclusion in a public database. In the next decade we are entering a golden era of science using gravity detectors like Pulsar Timing Arrays (PTA) and the Laser Interferometer Space Array (LISA), which will rely on BOBcat for electromagnetic information about candidates. As such, we are building BOBcat to interface with these instruments; for instance, data from the NANOGrav PTA are used to create sky sensitivity maps of BOBcat candidates. This functionality will allow the community to select the best candidates for targeted gravitational-wave searches.
Investigation of Material Parameters for Fabrication of ITO-based Dye-Sensitized-Solar Cells
Keslyn Stonum, Toni Sauncy
Much research has been done find alternatives to the use of non-renewable fossil fuels for energy production. Researchers have worked for decades to develop innovative ways to harness the power of the sun, which delivers over 1400 W/m2 on average to the surface of the earth daily, but solar cells currently produce only 2.8% of the share of total U.S. electricity generation. Most commercial solar cell technology is built on the silicon-based microelectronics infrastructure. Silicon based solar cells exhibit a maximum solar to electric power conversion of only 15% and involve the use of toxic chemicals that are pervasive in the microelectronics industry. Dye sensitized solar cells (DSSCs)have the potential to develop alternative, non-toxic, and relatively low-cost solar cell devices. These devices make use of naturally occurring compounds that interact effectively with sunlight, including anthocyanin- a chemical found in berry juices and chlorophyl. In this work, multi-layer DSSCs are fabricated using non-toxic components and characterized to determine optimization for various parameters, including layer thickness, variations in process parameters (temperature, time), and deposition techniques. Several successful DSSC samples were produced, but none which exhibited efficiencies nearing that of the commercial solar cell used for comparison. Details of materials, process, and results will be discussed.
Measurements of Qatar-9b & GSC 2087-1126 b
Mariah Houser, Richard P. Olenick, Arthur Sweeney
Significant physical parameters are known about the exoplanet Qatar-9b: mass m = 1.19 Jupiter masses, period P = 1.540731 days, and semi-major axis a = 0.0234 AU for its orbit around the spectral type K5V star. For the exoplanet, Candidate 1 (catalogue # GSC 2087-1126 b), period P = 0.7933 and semi-major axis a= 0.017 AU. We discuss photometric data taken in 2022 in the R-band with a 16-in remote telescope at the Dark Skies Observatory Collaborative in West Texas. The data are reduced and modeled to extract measurements and to deduce transit parameters. We discuss the use of a remote observatory and the analysis of data.
Multiple Paths to One Final Black Hole
Galina Bouyer, Oriol Ricart, Miguel Gracia-Linares, Pablo Laguna, Jacob Lange
The vast majority of gravitational wave events detected by LIGO and VIRGO have been the result of binary black hole mergers. The essential parameters to predict the result of these mergers are the spins and masses of the two initial black holes, and several pre-existing formulas solve for the final black hole from these initial conditions. Here we use one such formula and LIGO data to work in reverse to find several possible initial binary conditions for 16 confirmed gravitational wave sources. We obtained anywhere between 1 and 33 initial binary possibilities for each LIGO-observed black hole merger event and were able to better identify the parameter space that these possible binaries occupy. One future goal of this project includes testing the sensitivity of gravitational wave signals to shifts in these initial conditions by generating corresponding waveforms using PyCBC software.
Parallelizing Calculations of Type II-P Supernova Bolometric Lightcurves
Jeremy Lusk, Hypatia Meraviglia, Erik Stinnett
Models of supernova explosions can be checked against real-world supernovae by calculating the amount of nickel-56 generated as the remnant cools. The amount of Ni-56 is a function of the decay in total amount of light emitted by the supernova over time. To calculate the total light across all wavelengths emitted by the supernova in a single instant (the bolometric flux), we must integrate beneath the fluxes observed at specific wavelengths (monochromatic fluxes) and add the light not observed in the IR and UV. One method for calculating the observed flux (quasi-bolometric flux) is to fit monochromatic fluxes with a cubic spline and integrate beneath the piecewise function. To estimate the unobserved IR light, we fit a blackbody curve to our observed fluxes and integrate. Observed monochromatic fluxes carry error, and this error is propagated into bolometric flux. Small changes in the monochromatic flux points can affect the cubic spline fit or the blackbody fit dramatically. To estimate propagated error, we implement a method described by Martinez et al. (2021) of wiggling monochromatic fluxes, calculating the bolometric flux many times, and producing an average and standard deviation for the set. Structurally, this process consists of many independent calculations collated in a final step – well fit for parallelization. We compare message-passing interface (MPI) parallelization to linear computation on the flux wiggling problem, and discuss applications for more efficient, computationally neat code.
Dynamic Control of Energy Transfer in AuNR-PANI Hybrids through pH Change
Annette Jones, Emily K. Searles, Martin Mayer, Marisa Hoffman, Andreas Fery, Stephan Link, Christy F. Landes
Plasmonic nanoparticles support a localized surface plasmon resonance and large cross-section, allowing unmatched light absorption into confined areas; however, the ultrafast lifetime of the plasmon’s decay presents challenges in harnessing the energy before it dissipates into heat. Hybridization of plasmonic nanomaterials with energy transfer acceptors such as semiconductors would enable subsequent reactions to harness the energy offered from plasmonic nanomaterials. While fully inorganic hybrids have been well-studied, hybridization of plasmons with polymer acceptors has had limited investigation. Plasmon damping is observed in the scattering of individual gold nanorods upon the addition of a polyaniline shell and is a measure of energy transfer into the polymer. In this study, gold nanorod-polyaniline (AuNR-PANI) hybrids are investigated in different pH conditions to determine optimal conditions for the efficient transfer of energy from the plasmon to the PANI shell. Polyaniline is sensitive to pH changes, transitioning from emeraldine salt to pernigraniline base as pH increases. By monitoring the modulation in the single particle resonance energy and linewidth resulting from changes in the refractive index and plasmon dynamics, respectively, we investigate the plasmon dynamics of single hybrids. Using a microfluidic cell on an inverted hyperspectral dark-field microscope, we collected correlated single particle scattering spectra in acidic, neutral, and basic conditions. As the pH varies, the PANI absorption spectra shift resultant from the change in protonation state. Broader line widths, indicating a faster plasmon decay time due to energy transfer, were seen in more acidic conditions due to a larger spectral overlap between the AuNR core resonance and PANI shell absorption.
Observing Exoplanets by Photometric Transit Method.
Kiara Perez, Rudy Morales
We report WASP-163b and WASP-92b observations from CTMO. In addition, McDonald Observatory and CTMO Observatory observed KEPLER-44b. Observations and detection were made utilizing the Photometric Transit Method and a data reduction technique that eliminates picture flaws that might cause data processing inaccuracies. Software Astro-ImageJ is used to perform photometry on calibrated photos to determine the exoplanets’ radius and volume. WASP-163b orbits its 1.12 stellar radius host star with a radius of 13.57 (Earth) and a mass of 594. (Earth). WASP-92b orbits its F7 host star in 2.174 days and has an Earth-like mass and radius (Earth). Both WASP exoplanets are Super Jupiter-like because of their masses and radii. KEPLER-44b (alternate name KOI-204 b) orbits a G-type star in 3.2 days and is a gas giant, like Jupiter. KEPLER- 44b also has a mass of 1 Jupiter We used data from WASP-163b, WASP-92b, and KEPLER-44b to help understand exoplanet light curves for further confirmation and research on exoplanet databases.
Analysis of the Proximity Effect on Niobium Superconducting Resonators
Navya Chunduru
The Proximity Effect is a phenomenon of superconductivity that allows superconductivity to penetrate a non-superconducting material. In this study, we analyzed the superconductivity of superconductor-normal metal bilayer films (S/N) on highly superconductive Niobium resonators. We manipulated four different variables to measure analyze the superconductivity: temperature, magnetic field strength, transference, and thickness of the films.
Examining the Microstructures of the Carbon-Neodymium Binary System
Sabiha Younus, Steven Cavazos, Dr Elizabeth Sooby
Tristructural Isotropic (TRISO) fuel particles have been proposed as an innovative alternative fuel structure to monolithic fuel forms, such as the benchmark uranium dioxide fuel pellet, for nuclear energy generation. TRISO-coated fuel particles typically consist of a uranium-compound fuel kernel coated with carbon layers and a silicon carbide layer for fission product retention. TRISO fuel forms are candidates for high temperature gas-cooled reactors, light water reactors, and molten salt-cooled reactors. However, TRISO structural failure occurs through the degradation of silicon carbide by fission products. Among the thermophysical mechanisms driving the diffusion process, there is insufficient literature focusing on the metallic fission products in a binary carbide stoichiometry. This project involves characterization of three lab-synthesized carbide samples of an identified fission product, neodymium, Nd, utilizing scanning electron microscopy (SEM) and energy dispersive X-Ray spectroscopy (EDS). Overall, the structural behavior of the compounds seem to exhibit a more brittle state as carbon content increases.