Bulletin of the American Physical Society
Far West Section Fall 2021 Meeting
Volume 66, Number 12
Friday–Saturday, October 29–30, 2021; Virtual
Session G01: Poster Session I (3:00-3:45pm) |
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G01.00001: Studying the Accretion History of the Milky Way William Huang, Sofiya Belovich, Pujita Tangirala, Iona Xia, Paulo Villafana, Miranda Apfel, Constance Rockosi, Puragra Guhathakurta An important goal of cosmology is to determine the Milky Way's accretion history, the history of dwarf galaxies accreting to form the stellar halo. Each individual accretion event forms a unique structure in the halo, and these features, known as substructure, explain the galaxy's accretion history. To examine substructure, we compare data of the HALO7D survey fields from the Gaia space observatory to the Besan\c{c}on model of the Milky Way, which notably has no substructure. A comparison between galactic latitude and number of stars illustrates that both the Besan\c{c}on model and Gaia data show an increase in stars near low latitudes, but little variation due to substructure. Similar trends were found between proper motion and color, with larger ranges of proper motion corresponding with increasing color while magnitude is constant. Due to the large error in Gaia parallax, the inverse relationship between distance and proper motion present in the Besan\c{c}on model was absent in Gaia data. We determined that proxies such as proper motion versus color demonstrate a similarity between the Milky Way and Besan\c{c}on model, but do not yield substructural information. Future work includes comparison of LOS velocity from Keck DEIMOS spectra of stars in these fields. [Preview Abstract] |
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G01.00002: Heisenberg uncertainty principle disproved Chirag rai 1. Imagine there are 2 subatomic particle 2. Measure their mass stick them together 3. Let them spring apart 4. What happens? 5. Their positions and velocities are related But…… The uncertainty principle says, If we measure the position of one…then we cannot measure its velocity. But we can still measure the velocity of the 2nd particle and since they are mathematically related we can then determine we can determine the velocity of the first particle so we’d know both its position and velocity without measuring them both. 6. suppose you have to measure the position and velocity of an object which does not exist at a time but you can't, because the uncertainty principle says you can't measure the position and velocity at a time, how I am going to tell: you have to measure the position of the imaginary object and imagine there the same mass object which is mathematically connected let's suppose there are 2 objects A and B first measure the position of the A object and then measure the velocity of object B. After you measure the position and velocity you will simultaneously get the position and velocity of A as well as B because they have equal mass and they are connected mathematically. [Preview Abstract] |
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G01.00003: Molecular Dynamics Simulations of F1-ATPase Using GPU Supercomputer Matthew Anderson, Sándor Volkán-Kacsó Single-molecule imaging has produced many videos of biomolecular events, including the binding and release of ADP and inorganic phosphate (Pi) from ATPase. However, the poor video quality of single-molecule imaging makes it inadequate for robust research. Recently, molecular dynamics simulations have become able to access the microsecond timescales associated with the release of ADP and Pi. Using MD simulations, we have developed a method of describing large domain motion of F1-ATPase subunits with large trajectory files. These large trajectories obtained from unbiased MD simulations contain the collective coordinates associated with the bending and torsional motion of subunits. These all-atom simulations produced three distinct trajectories using an X-ray crystallography structure with all three active subunits occupied by nucleotides. Our hypothesis suggested that, under these conditions, an ADP should be released within a few microseconds. Early simulations showed that one trajectory resulted in the release of an Pi. However, it was not found that the ADP was released in this during the microsecond time frame. This project optimized our simulations to capture the release of Pi and ADP. Biased techniques such as steered MD and metadynamics may be used to improve sampling later. [Preview Abstract] |
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G01.00004: Towards a better determination of Big G Emily Ord, Muchuan Hua, Rutuj Gavankar, Marvin Quenten, Stephan Balmer, W.M. Snow, C.D. Hoyle, R.S. Decca The Newtonian gravitational constant, G, is a fundamental constant in nature not linked by any complete theories to other forces of nature. Compared to all other fundamental constants, G is known with the least precision. Over the last 200 years, its value has been repeatedly measured, and leading experiments have produced values which are incompatible with one another. Compared to the most precise experiment, some measured values differ by up to 50 times the experimental uncertainty. Recently, two experiments have measured consistent results at the 12 ppm level. After examination of the methodology used in previous measurements, the research group at IUPUI, in collaboration with Humboldt State University and Syracuse University, will use multiple approaches to determine G within a singular torsion pendulum apparatus. We expect to obtain a measurement at the 2 ppm level using these new methods. By continuing the use of a torsion pendulum apparatus, we also hope to better understand the current discrepancies among previous experimental results. This poster will focus on the implementations made to help obtain a more precise measurement of G. [Preview Abstract] |
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G01.00005: Study on Nanoparticles in the Photoactive Layer in Photovoltaic Cells Using Chemical and Computational Analysis Kyumin Kim The current research on organic solar cells has discovered that there are many advantages regarding the use of these solar cells. Organic, polymer-based solar cells, also commonly referred as OSCs, have been found to be a new and better alternatives to inorganic cells in several ways. In this paper, Density Functional Theory (DFT) and calculations were used to study electronic properties of the nanoparticles in the photoactive layer in a solar cell. Various fullerene derivatives including P3HT:PCBM complex were modeled using a molecular editing program to define the efficiencies of the nanoparticle compounds. Three factors, such as thermodynamic stability, dipole moment, and electrostatic potential map, were considered. Relative angular orientation between the two molecules was also considered in finding the stability and the total energy of the P3HT:PCBM complex. The DFT calculations and quantum physical method were used to characterize the electronic properties of those configurations. Fullerene complexes that were optimized in a relatively short period of time were also predicted to be more thermodynamically stable, as short optimization times generally equate to spontaneous converging. [Preview Abstract] |
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G01.00006: Simulations of Alpha Accompanied Ternary Fission Jonathan Fuzaro Alencar Alpha accompanied ternary fission is the process by which the nucleus of an atom breaks apart into three charged fragments including an alpha particle. The Neutron Induced Fission Fragment Tracking Experiment (NIFFTE) uses a nuclear fission time projection chamber (TPC) to construct three-dimensional ionization profiles of fission fragments. To compare data analysis done by NIFFTE on a U258(n,f)/U235(n,f) cross-section, dynamic simulations of alpha accompanied ternary fission were reproduced using Monte Carlo methods to generate initial conditions at the nuclear scission point. Ionization profiles within the TPC were then emulated by numerical integration of the Bethe-Bloch formula. The current status of the simulation’s fidelity and agreement with experimental results will be presented. [Preview Abstract] |
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