Bulletin of the American Physical Society
Joint Fall 2017 Meeting of the Texas Section of the APS, Texas Section of the AAPT, and Zone 13 of the Society of Physics Students
Volume 62, Number 16
Friday–Saturday, October 20–21, 2017; The University of Texas at Dallas, Richardson, Texas
Session F1: Poster Session I |
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Chair: Jason Slinker, University of Texas at Dallas Room: DGAC Texas Instruments Inspiration Hall |
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F1.00001: Study on the Neurochemicals Affecting Psychological Chemical Imbalance Yoonah Lee, Peter S. Lee In recent years, treatment for depression, anxiety, and mental disorders impacted by chemical imbalances in neurotransmitters has been analyzed through advanced computational biomedical technology. To determine the relationship between chemical imbalances and psychological disorders, it is critical to establish the functionality of each neurotransmitters that carry the information between neurons and their target cells through the synaptic cleft. Using the computational biomedical technology, chemical analysis of different amino acid sup-plements such as glutamine, tyrosine, phenylalanine, and methionine potentially leads to an op-timal solution in balancing neurotransmitters and mood regulations. To analyze the potential relationship between neurotransmitters and amino acid supplements, this research models selected neurotransmitter and amino acid supplement molecules using chemical softwares designed to build virtual molecules and calculate optimized geometry using the density functional theory. The optimization of modeled structures is measured using their theoretical values and the molecule’s atomic properties. The efficiency of these molecules is determined by assessing their thermodynamic stability. [Preview Abstract] |
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F1.00002: Comparing the Dynamics of Fake News and Real News on Social Media Parker Haggerty, Dr. Hana Dobrovolny The widespread adaptation of social media has had a profound impact on how news spreads, regardless of its veracity. We use a nonlinear mathematical model to compare the dynamics of real news stories and fake news stories on twitter. We adapt the concept of the Basic Reproductive Number- a measure of how infectious a virus is- as the primary means for this comparison. In order to collect data we use python to search twitter for hashtags relating to a specific news story, and then count the amount of tweets per day to use that hashtag. We fit this data to our model to calculate the Basic Reproductive Number, and then analyze and discuss our results. [Preview Abstract] |
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F1.00003: Passive Tracking of a Solar Panel with Shape Memory Alloys Dillon Wester, Keeley Johnson, Angela Douglass This experiment seeks to achieve passive tracking of a solar panel through the use of unique metals called shape memory alloys (SMAs). SMAs were configured to rotate a solar panel without the consumption of energy from the solar system because of their ability to change shape when heated above their transformation temperature. The SMA can be activated by sunlight focused from a Fresnel lens. The advantages of SMA over other tracking methods include no maintenance, longevity, and two-way shape memory. The solar panel size, support stand, and electronics were optimized with the ultimate goal of powering an 11 W street light. Experiments were conducted to determine the pulling force and travel of various sizes of SMAs to determine optimal rotor design. [Preview Abstract] |
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F1.00004: Confirming an Accelerating Universe through Cosmological~Constraints Lindsey Rayborn In the early twentieth century, Edwin Hubble confirmed~that the universe was not stationary, but expanding since its origin. More recently, scientists found that the universe is accelerating in its expansion.~To explore the possibility of an accelerating universe, cosmologists use the Friedmann--Lema\^{\i}tre--Robertson--Walker (FLRW) metric to model the geometry of the universe determined by its matter~and energy~density. The~model~assumes that the universe is homogeneous and isotropic at a large scale and that the universe is either expanding or contracting as a function of time. Furthermore,~the~standard model of cosmology (Lambda-CDM)~provides explanations for the existence of cosmic microwave background, distributions of large-scale structures in the universe, presence of light elements from H to Li, and the acceleration of the expansion of the universe. Cosmologists also use the FLRW metric to obtain exact solutions to the field equations~developed by Einstein. The resultant Friedmann equations~show that the expansion of space varies with time and with the geometry of the universe. Three possible solutions result from the combination of values that describe the energy density and pressure of matter in the universe in addition to parameters describing the geometry. It is possible to confirm the acceleration of the universe's expansion by constraining and examining several parameters pertaining to the behavior and characteristics of the universe from comparison to various cosmological observations. [Preview Abstract] |
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F1.00005: Atomic Structure and the Periodic Table Shannon Perry, James Espinosa, Noah Pinto The current periodic table seen in physics and chemistry textbooks are direct descendants of the original scheme proposed by Mendeleev in the nineteenth century. With the advent of quantum mechanics, a better understanding of atomic structure was attained, allowing chemists in the 1930's to propose a better periodic table that allows students to see the chemical and physical periodicities of atoms. This new organization was called the 32 column atomic structure periodic table. In the 1960's, Linnett proposed a modification of the Lewis-Langmuir octet rule which allowed him to create molecular models that greatly reduced the use of the resonance. Luder quickly followed this development with a clear presentation of what a static picture of each element would look like, building on the cubical atom of Lewis. We have used VisualPython to create an interactive 32 column periodic table that allows students to see the Newtonian pictures of the chemical elements. [Preview Abstract] |
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F1.00006: Simulating the Precession of Mercury Nathan Redmon, Lincoln Bhattarai, Pradeep Ojha, Krista Chanaritthichai, James Espinosa The orbit of Mercury precesses at a total rate of 575 arc seconds per century. The gravitational forces from the other 7 planets produce a rate of 535$^{\mathrm{\mbox{'}\mbox{'}}}$, leaving a 43 arc seconds unaccounted. Albert Einstein's General Theory of Relativity can account for the missing discrepancy of Newton's law of gravity. It is not generally known that Oppenheim in 1895 showed a modified Newton's law would produce the missing amount, a full 20 years before Einstein. In 1908, Walter Ritz used this modification in his theory of electromagnetism. We will use his theory to simulate the precession of Mercury and demonstrate that his theory gives the correct amount. [Preview Abstract] |
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F1.00007: Investigating the Nature of Dwarf Spiral Galaxies Sachithra Weerasooriya, Jacqueline Dunn Several studies have proposed that dwarf elliptical / spheroidal galaxies form through the transformation of dwarf irregular galaxies. Early and late type dwarfs resemble each other in terms of their observed colors and light distributions (each can often be represented by exponential disks), providing reason to propose an evolutionary link between the two types. The existence of dwarf spirals has been largely debated. However, more and more recent studies are using the designation of dwarf spiral to describe their targets of interest. This project seeks to explore where dwarf spirals fit into the above mentioned evolutionary sequence, if at all. Optical colors will be compared between a sample of dwarf irregular, dwarf elliptical, and dwarf spiral galaxies. The dwarf irregular and dwarf elliptical samples have previously been found to overlap in both color and surface brightness profiles shape when limiting the samples to their fainter members. A preliminary comparison including the dwarf spiral sample will be presented here. Initial results indicate a potential evolutionary link that merits further investigation. Additionally, dwarf galaxies will be explored through the use of N-body simulations. The formation and stability of spiral structure present in dwarf disk galaxies will be explored using models built with GalactICS and evolved using Gadget 2. [Preview Abstract] |
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F1.00008: Anomalies of the 2017 Solar Eclipse David Winski, Alexandria Mendoza, Tyler Sanchez, Timothy Renfro, Wayne Keith, Matthew Huddleston Data about light intensity and temperature was collected from Dearborn, MO and Nashville, TN during the Solar Eclipse that occurred on August 21, 2017. Both of these cities were located in the path of totality. Dearborn experienced 2 min. 29 sec. of totality and is about 21 miles from maximum totality while Nashville experienced 1 min. 55 sec. of totality and is about 19 miles from maximum totality. Much of the data had to be discarded due to cloud coverage. However, several anomalies, such as frequent dips in the light intensity graphs, do match up in both sets of data right before the point of totality. These anomalies suggest a pattern that will be discussed in the presentation.~ [Preview Abstract] |
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F1.00009: Solar Wind Properties During High Speed Streams Mikayla Streetman, Taylor Crist, Lauren Daniels, Jocelin John, Hector Carranza, Ramon Lopez Solar wind is the continuous flow of particles from the sun. High speed streams are formed by higher speed solar wind originating from low density solar regions called coronal holes. High speed streams are of interest because they can produce a strong southward z-component (Bz) of the interplanetary magnetic field (IMF), the solar magnetic field dragged out by the solar wind. A strong southward Bz or long duration thereof drives magnetic storms. We are determining the properties of high speed streams by analyzing solar wind data from OMNIWeb; a database of various satellites that uses algorithms to propagate solar wind data to Earth's predicted bow shock. We will be presenting a collection of high speed streams and their corresponding solar wind properties; in particular, proton density and Bz fluctuations from the baseline average. [Preview Abstract] |
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F1.00010: An Overview of Magnetopause Location's Dependence on Upstream Solar Wind Conditions Using Observational THEMIS Data Chris Sherrill, Chelsi Nelson, Torin Rose, James Zapp, Richard Bonde, Ramon Lopez Solar wind is the continuous flow of charged particles from the Sun. As it travels outward, it carries the Sun's magnetic field along with it forming the interplanetary magnetic field, or IMF. The boundary between the IMF and Earth's magnetic field is called the magnetopause, and its location depends on the upstream solar wind conditions. NASA'S Time History of Events and Macroscale Interactions during Substorms, or THEMIS, is a series of probes in which their highly elliptical orbit puts them in a position to cross over the magnetopause. We cataloged a series of THEMIS crossings in order to determine the location of the magnetopause. Upstream solar wind conditions were analyzed using OMNIWeb; a database of various satellites that uses algorithms to propagate solar wind data to Earth's predicted bow shock. We present an overview of THEMIS crossings and the solar wind conditions that affect the movement of the magnetopause. [Preview Abstract] |
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F1.00011: Thermal Treatment Technique on Structural and Optical Properties of LaF3:Yb,Er Alan Perez, Yuanbing Mao, Madhab Pokhrel Due to their interesting surface and structural properties, recent years have seen the emergence of nanoparticle (NP) phosphors for use in numerous applications including defense and industry. Erbium (Er3$+)$ and Ytterbium (Yb3$+)$ doped Lanthanum fluoride (LaF3) NPs were synthesized via molten-salt synthesis (MSS) and systematically annealed to optimize crystal structure optical properties. Chemical analysis of the NPs includes X-ray diffraction (XRD) with Rietveld analysis, scanning electron microscopy (SEM), Raman, X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) spectroscopy, and quantum yield (QY) measurements. The study found an increase in efficiency for near-infrared (NIR) and mid-infrared (MIR) emissions, as well as for the visible spectra in the NPs. The point of oxidation producing Lanthanum oxyfluoride (LaOF), which dampens NIR and MIR emissions due to multi-phonon relaxations (MPR), is also discussed. To further elaborate the technology in photovoltaics, scintillators, and biomedical applications, optimization of emissions by LaF3:Yb,Er will help understand the highly disputed energy mechanism of Erbium; and by extension, the optical mechanisms of other rare-earth (RE) phosphors. [Preview Abstract] |
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F1.00012: An Attempt to Understand the Nonequilibrium Statistical Physics of Microbes Michael Olaya, Nick Utley, Preet Sharma Our attempt is to study the behaviour of microbes through the framework of nonequilibrium statistical physics. Microbes can be understood through their activity. Sometimes they are more active sompared to other times. This behaviour can be attributed to their surroundings and how they change. We can also understand the dynamics of a microbe through its interactions with the surroundings. A typical way in which a microbe is understood to behave is a random motion which can be explained by Brownian motion. Since the surroundings affect this behaviour, we have attempted to study as to how the perturbations in the surroundings would affect the microbes. Our attempt is also towards explaining this behaviour of microbes through the Fokker-Planck equation and its perturbations. [Preview Abstract] |
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F1.00013: Ultrasensitive Detection of Neurotransmitters by Surface Enhanced Raman Spectroscopy for Biosensing Applications Katia Ochoa, Kevin Bennet, Jonathan Tomshine, Seth Hara, Malcolm McIntosh, John Ciubuc, Emma Sundin, Chao Qiu, William Durrer, Michael Eastman, Felicia Manciu In this study, fabrication of silver nanoparticles (Ag NPs) as surface-enhanced Raman spectroscopy (SERS) active platforms enabled detection of serotonin, adenosine, and dopamine at concentrations as low as 10$^{\mathrm{-11}}$ molar. Besides demonstrating the potential value of this high sensitivity Raman recording of these very important analytes in the diagnosis of numerous neurological diseases, we observed variations in the intensities of characteristic Raman signatures that indicate changes in the molecular orientations of the neurotransmitters in the proximity of the silver surface, as well as potential chemical interactions. We also found that the particular Raman cross sections of neurotransmitter molecules and their densities close to the surface of Ag NPs play a significant role in preferential SERS enhancement. This study not only provides direct evidence that, using Raman spectroscopy, label-free detection of trace amounts of neurotransmitters is achievable, but it further advances knowledge of their interactions at the interface with metal nanoparticles. [Preview Abstract] |
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F1.00014: Tunable Surface Interactions in Adsorbing Polymer Solutions Sorour Hosseini, Marian Manciu Grafted polymers typically enhance the stability of colloidal dispersions, via the long ranged sterical repulsion due to the overlap of their polymer brushes, which can be thicker that the typical range of the DLVO interactions. However, if the polymers are adsorbing on the colloidal surfaces, there is the possibility of bridge formation between particles and therefore long-range attractions are induced (a procedure commonly used for the flocculation of colloidal suspensions). The two effects are competing, and might result in attractive interactions at larger distances and repulsive interactions at shorter distances. These distances, as well as the magnitude of the interactions, depend on the system parameters, such as the grafted density in the brush, the length of the polymer, the adsorption energy between monomers and surfaces, the quality of the solvent or the polymer charge (for polyelectrolytes). We will show that a simple model, which suggests that the configuration of a polymer chain grafted on the interface can be described in terms of short configurations (loops, trains and tails), for which the probability of occurrence are calculated via a constrained minimization, can be employed to determine the interactions between polymer grafted colloidal particles. By tuning the system parameters, the attractive or repulsive interaction can be tailored at any desired distance. [Preview Abstract] |
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F1.00015: Comparing Infection Parameters for Respiratory Syncytial Virus in Different Aged Cotton Rats Shaheer Khan, Hana Dobrovolny Viral infections pose a significant threat to individuals. Viral models can assist health professionals in developing more effective treatments while also lessening the costs in researching and developing new treatments. Of particular interest are the similarities and differences for a viral infection across different age groups. In both rats and humans, the immune system develops over time, leading to different immune responses at different ages. In this study, experimental data of respiratory syncytial virus (RSV) viral count in different aged cotton rats were fit to a mathematical model in order to obtain parameter values. Six parameter values were determined and used to calculate the eclipse phase length, infection phase length, basic reproductive number, and infecting time. These values were compared by age and collection site. The resulting comparison offers insight regarding the viral kinetics of RSV across different age groups. [Preview Abstract] |
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F1.00016: Characterizing the efficacy of anticancer drug treatment using mathematical models Hope Murphy, Elizabeth Sizemore, Anton Naumov, Hana Dobrovolny \newcommand{\ic}{\ensuremath{\mathrm{IC}_{50}}\xspace} \newcommand{\emax}{\ensuremath{\epsilon_\mathrm{max}}\xspace} In order to determine correct dosage of chemotherapy drugs, the effect of the drug must be properly quantified. There are two important values that characterize the effect of the drug: \emax is the maximum possible effect from a drug, and \ic is the drug concentration where the effect diminishes by half. Currently, the technique used to measure these quantities gives estimates of the values that depend on the time at which the measurement is made. We use mathematical modeling to test a new method for measuring \emax and \ic that gives estimates independent of measurement time. We fit treatment data from the literature to determine values for \emax and \ic using mathematical models under two assumptions: that the drug reduces growth rate, or maximum number of cells. Our method produced \ic estimates similar to estimates derived using current techniques. This work is intended to characterize the efficacy of anticancer drug treatments and determine the correct doses before trying those in patients to get the most effective therapeutic treatment. [Preview Abstract] |
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F1.00017: Viral transport mechanisms in the respiratory tract and their role in infection dynamics Hana Dobrovolny, Gilberto Gonzalez-Parra Some respiratory viruses can lead to serious lower respiratory infection (LRI). LRI can cause longer infections, lingering respiratory problems, and higher incidence of hospitalization. We develop a mathematical model of viral dynamics to study the role of transport mechanisms in the occurrence of LRI. Our model uses two compartments to simulate the upper respiratory tract (URT) and the lower respiratory tract (LRT) and assumes two distinct types of viral transfer between the two compartments: diffusion and advection. We find that a range of diffusion and advection values lead to long-lasting infections in the LRT, elucidating a possible mechanism for the severe LRI infections observed in humans. [Preview Abstract] |
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F1.00018: Computing osmotic permeabilities of aquaporins AQP4, AQP5, and GlpF from near-equilibrium simulations Thierry Wambo, Roberto Rodriguez, Liao Chen Measuring or computing the single-channel permeability of aquaporins/aquaglyceroporins (AQPs) has long been a challenge. We report large scale simulations of osmotic current under sub M gradient through three AQPs (water channels AQP4 and AQP5 and glycerol-water channel GlpF. These simulations were implemented with hybrid periodic boundary conditions devised to avoid the artifactitious mixing across the membrane in a regular PME simulation. The computed single-channel permeabilities at 5~\textdegree C and 25~\textdegree C are in agreement with recently refined experiments on GlpF. The Arrhenius activation energies extracted from our simulations for all the three AQPs agree with the \textit{in vitro} measurements. We observe that AQP4, that is particularly rich in the central nervous system, is more efficient in water conduction and more temperature-sensitive than other water-only channels (excluding glycerol channels that also conduct water when not inhibited by glycerol). [Preview Abstract] |
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F1.00019: Multigene Delivery and Gene-selective Imaging with Single-walled Carbon Nanotubes Md Tanvir Hasan, Elizabeth Sizemore, Lynn Kirkpatrick, Anton Naumov Single Wall Carbon Nanotubes (SWCNT) have a great potential in biological applications since they possess quasi-one-dimensional structure ading internalization and exhibit fluorescence in near-IR with reduced biological autofluorescence background. In this work, we use SWCNTs for \textit{in-vitro} multi-drug delivery and imaging: each gene or drug is non-covalently bound to SWCNTs of a specific chirality and can be tracked and assessed separately. Single chirality SWCNTs are separated by a modified Aqueous Two-Phase Extraction (ATPE) method with a purity of up to 40{\%} with only (1-5) {\%} contributions from other chiralities. This allows observing microscopically the fluorescence mainly from the target chirality. Separation surfactants are removed by repeated centrifugal washing/ ablation procedure and replaced by siRNA. Finally, chirality-sorted SWCNTs are applied as multidrug delivery vehicles carrying non-covalently complexed siRNA gene therapeutics into liver cancer cells. Internalization of SWCNTs of each specific chirality is observed via near-IR hyperspectral fluorescence microscopy allowing to record wavelength-resolved images within emission bands of each individual chirality, and therefore assess each gene's delivery separately. The results of this work indicate that SWCNT can serve as efficient multidrug/gene delivery carriers for imaging and therapeutics mapping out internalization pathways and effects of each drug/gene separately. [Preview Abstract] |
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F1.00020: Exploring the Use of Graphene Oxide as Imaging/Sensing/Delivery Platform Elizabeth Sizemore, M.T. Hasan, G. Akkaraju, A.V. Naumov Graphene oxide (GO) is a functional derivative of graphene that possesses a number of exceptional properties beneficial for molecular drug delivery/imaging/sensing applications. Those include pH-dependent fluorescence emission, water solubility and large platform for functionalization with drug molecules. In our work, we utilize these properties to yield a multifunctional transport/imaging/sensing platform for the delivery and analysis of cancer treatment within cells. GO serves as an imaging agent due to its intrinsic fluorescence in the visible, and as a pH-sensor due to its pH-dependent emission. In order to provide the ideal conditions for cellular imaging and sensing fluorescence of individual GO flakes was assessed for a variety of pH levels, and the sizes of GO flakes were adjusted for optimal internalization. In-vitro fluorescence microscopy with healthy (HEK-293) and cancer (HeLa and MCF-7) cells shows successful internalization of GO into cytoplasm and characteristic pH-dependent response of GO emission in the acidic environments of cancer cells. The results of this work suggest GO as an innovative multifunctional delivery/imaging/cancer sensing platform for cancer therapeutics. [Preview Abstract] |
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F1.00021: The inverse and direct Hofmeister series of Hen egg lysozyme at pH below isoelectric point (pI) as seen by SAXS Pawan Koirala, Jose L. Banuelos Protein interaction and aggregation processes are important in understanding many physiological processes in living organisms. Diseases such as Alzheimer's, Kreutzfeld-Jakob and Parkinson's are associated with protein or peptide aggregation phenomena whereas the short-range order of crystalline proteins contributes to eye lens transparency benefitting our visual system. We are focused on determining the shape, size, and nature of interactions between the protein molecules (lysozyme) in solution at low and high salt concentration of various sodium salts at certain pH by using Small-angle X-ray scattering (SAXS). For example, data fits using an ellipsoidal form factor yield an average polar radius of 38.5 {\AA} and equatorial radius 15.5 {\AA} for 0.1M ionic strength solutions with 60mg/ml protein concentration. [Preview Abstract] |
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F1.00022: Effects of Membrane Protein nAChR on Phase-Separated Model Membranes Jigesh Patel In this study, the effects of adding 2 mol{\%} of membrane protein nAChRs to DOPC/DSPC/cholesterol lipid bilayers containing coexisting phases are investigated. Previously, no 4-component phase diagram, with nAChRs protein as one of the components, has been studied. This work is the first study of this kind that investigates the effect of ion-transmitter nACHRs on L$_{\mathrm{o}}+$L$_{\mathrm{d}}$ phase boundaries. The modification of phase boundary by nAChRs is determined using fluorescence microscopy on giant unilamellar vesicles (GUVs). After phase boundaries are determined, thermodynamic tie-lines and protein's partition coefficients will be measured. Those data will allow us to precisely determine the exact concentrations of nAChRs in various cell membrane domains. Accurate measurement of the perturbations of the phase boundaries by the protein could serve as a means to quantitatively understand the universal behavior of a range of membrane proteins. [Preview Abstract] |
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F1.00023: A Study of the Physical and Chemical Stabilization of the DNA Molecule Due to the DNA Mutation Michelle Paik Kwon, Richard Kyung A spontaneous DNA mutation observed in chemical or biological transformation can lower the energy of the system, at least locally. The enthalpy or potential energy of the product after the most of the chemical reactions becomes smaller than that of the reactant. But in case of any endothermic reaction, in which heat energy becomes chemical potential energy, the reactions higher the chemical potential energy of their products. Study on the thermodynamic enthalpy and the kinetics of DNA is complicated not only since the system is made of a large number of elements such as nitrogenous bases, sugar, and phosphate group, but also DNA doesn't exist in isolation. In this research, the deamination of cytosine, which is frequent spontaneous mutation, is computationally and thermodynamically tested for the local double helical structure of the DNA molecule to assess its stereo-chemical effects. To determine whether the DNA molecule is locally destabilized by a spontaneous mutation, the research uses physical and chemical softwares to further display the optimized geometry energy levels and calculate each compound model’s theoretical values. [Preview Abstract] |
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F1.00024: Biophysical and Material Analysis of the Anesthetic Needles to Reduce Nerve Tissue Damage Yongjae Ryu, Yeonghyeon Lee, Jae Suk Park Needle penetration of a nerve leads to a short or long-term dysesthesia such as paresthesia or permanent damage if it is not properly administered. Since the anesthetic needle cannula is long slender and thin-walled column, it is vulnerable to bending or fracture of the needle. Also plastic hypodermic needles, which are easy to adjust the ratio of synthetic polymers to increase the strength of material properties, found to be cost effective in manufacturing. This paper presents the study of the material properties and buckling behaviors of the needles using stability or safety analysis of needles fabricated by polymeric plastic materials and metals which enables doctors to carry out micro-injection. We considered penetration forces for diverse variables such as needle gauge size and needle penetration angles. Also, since the needle cannula is thin-walled column, such as 0.8 mm outer diameter with a 0.2 mm wall thickness, the material property and buckling behavior of the needles are analyzed by numerical and computational simulations. Also the mechanical property factors such as elastic modulus and brittleness of the needle are considered to determine how much pressure is required to barb each needle. [Preview Abstract] |
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F1.00025: Corrections imposed by the Schwarzschild spacetime on the parameter space and bound debris of tidal disruption events Juan Servin, Michael Kesden Stars on orbits with pericenters sufficiently close to the supermassive black hole at the center of their host galaxy can be ripped apart by tidal stresses, with the resulting bound debris producing what is known as a tidal disruption event(TDE). We provide a self-consistent, unified treatment of TDEs by non-spinning black holes, investigating several effects of general relativity on the parameter space of the disruptions. We provide a new mapping procedure that translates TDEs between Newtonian gravity and general relativity, allowing us to better compare predictions in both gravitational theories. For deep encounters leading to full disruption in both theories, the stronger tidal forces in relativity imply that the star is disrupted further from the black hole and that the debris is therefore less tightly bound, leading to a smaller peak fallback accretion rate and thus fainter TDEs. We also present preliminary results from our new model for predicting the evolution of the bound stellar debris. The TDE literature often chooses to homogenize the debris, tracing only the most bound orbit to describe this evolution. We distinguish debris elements based on their binding energies and incorporate relativistic effects, comparing our results with those of the TDE literature. [Preview Abstract] |
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F1.00026: Statistical Analysis for Finding the Shape of a Glowing Object Zakary Noel, Suzanne Wheeler, Gabbrianna Escamilla, Daniel Dove, Cristian Bahrim Preliminary experiments indicated that we can differentiate between a glowing object of polygonal shape with n sides based on the interpretation of polarimetric measurements, but no quantitative analysis had been done. We now expand upon this proof of concept with a deeper and more meaningful statistical interpretation of data which allows us to create a well-calibrated experiment and therefore better find the actual shape of a glowing object. We have improved the data acquisition process using a computer based approach where we uniformly rotate a polarizer in front of a glowing object with an electric motor, and we use an improved optical setup to focus the contour of the glowing object on the aperture bracket of the light sensor. This alignment greatly reduces the uncertainty in data acquisition and in the error bar in data processing of the light information. From this result we can better extract the shape of the object as a ratio of the luminosity of the glowing signal on the light sensor with respect to a control signal. This experimental method can be used for more accurate astronomical measurements from finding the shape of stellar objects as well in metallurgy. [Preview Abstract] |
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F1.00027: 2-D Hybrid Model to Study Flow Curvature Effect on Low Frequency Plasma Turbulence S Sen, D Lin, W Scales, M Goldstein In this study of flow curvature effects, a two-dimensional hybrid model is used to simulate the Kelvin-Helmholtz instability (KHI). The hybrid model treats the ions as particles, and electrons as massless fluid. Pressure and resistivity are assumed as isotropic. A classical configuration for the study of KHI is investigated, i.e. transverse shear flow to uniform background magnetic field. This is thought as the most unstable situation in magnetohydrodynamic (MHD) theory. There are 50 super particles per cell in the current simulations, which number could be increased to as much as 200 in the future. The boundary is periodic along the flow direction and reflective in the perpendicular direction. The code was originally developed by the Los Alamos National Laboratory and has been successfully applied to the study of Kelvin-Helmholtz instability on the Earth's magnetopause. In this study, the code has been running on the Advanced Research Computing (ARC) platforms of Virginia Tech. Four distinct shear profiles are simulated to investigate the effects of flow curvature on the growth of the KH instability: uniform flow, linear shear without curvature, quadratic profile with positive curvature, and quadratic profile with negative curvature. [Preview Abstract] |
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F1.00028: Use of Propyl Sulfonic Acid Functionalized Silica to diminish the dehydration of CsH2PO4 at superprotonic transitions phase temperatures Israel Martinez, Cristian Botez, Juan Leal, Alex Price, Andrea Montgomery, Sonam Lhamo Cesium Dihydrogen Phosphate (CDP) exhibits a sudden, 1000-fold increase in protonic conductivity at when heated up to 235C from room temperature. However, CDP undergoes a chemical decomposition into a nonconductive oxide (cesium pyrophosphate) at these temperatures. Propyl Sulfonic Acid Functionalized Silica (PSAFS) is a well-known strong cation exchanger for polymers. A mechanical mixture based on a mole fraction of 0.7 CDP to 0.3 PSAFS was prepared for Electrochemical Impedance Spectroscopy (EIS) under ambient and humid conditions. EIS measurements were taken from 200C to 260C with a heating ramp of 2.5 C/min every 10 degrees and the sample was held at 260C for 20 hours. While at isotherm, impedance data was collected every hour. Conductivity values for the composite at hour 20 were 1.2 x10$^{\mathrm{-04}}$ Scm$^{\mathrm{-1}}$ in ambient conditions, and 2.1 x10$^{\mathrm{-03}}$ Scm$^{\mathrm{-1\thinspace }}$under humid conditions. Neat CDP produced values of 7.1 x10$^{\mathrm{-07}}$ Scm$^{\mathrm{-1}}$ and 5.9 x10$^{\mathrm{-06}}$ Scm$^{\mathrm{-1}}$ in ambient and humid conditions respectively. The composite out performed neat CDP with respect to time in both ambient and humid conditions [Preview Abstract] |
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F1.00029: Scalable single step perovskite deposition technique for optoelectronic device fabrication Mehedhi Hasan, Swaminathan Venkatesan, Junyoung Kim, Nader Rady, Sandeep Sohal, Eric Neier, Yan Yao, Alex Zakhidov Perovskites have recently emerged as competitive semiconductor for optoelectronic devices. Perovskites are typically represented by ABX$_{\mathrm{3}}$, obtained from the reaction between organic salt (AX) and lead salt (BX$_{\mathrm{2}})$. Spin coated films are rough due to rapid reaction kinetics. Solution of this issue, using chemical adducts or sequential coating are shown to be effective, yet unsuitable for scalability. We report a methylammonium-acetate based one step spin coating technique, suitable for scalable device fabrication. Lead iodide (PbI$_{\mathrm{2}})$, methylammonium-acetate (MAAc) and methylammonium-iodide (MAI) mixed in different ratios were used as starting precursors for perovskite deposition. The films derived from different ratio exhibited crystallization of perovskite phase during spinning. The technique is optimized for benchmark perovskites CH$_{\mathrm{3}}$NH$_{\mathrm{3}}$PbI$_{\mathrm{3\thinspace }}$and CH$_{\mathrm{3}}$NH$_{\mathrm{3}}$PbBr$_{\mathrm{3\thinspace }}$and expected to be useful for other members of perovskite family. Morphological, structural and optical study of deposited film reveal the superiority of the film synthesized using 1:1:1 ratio of PbI$_{\mathrm{2}}$: MAAc: MAX. Further, the technique is utilized for solar cell and LED fabrication. Evidently, MAAc precursor based solar cells exhibit superior performance than reported performances of the cells used different concurrent deposition technique of perovskite with similar architecture of our devices. Likewise, LED fabricated from 1:1:1 ratio of precursors achieved 0.34{\%} EQE which is a big jump compared with other ratios. [Preview Abstract] |
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F1.00030: Conductivity of CsH2PO4 and SiO2 composites under ambient and humid conditions over time Sonam Lhamo, Andrea Montgomery, Israel Martinez, Juan Leal, Alex Price, Cristian Botez Cesium Dihydrogen Phosphate (CDP) is a well-studied solid state protonic conductor for hydrogen fuel cell electrolyte applications at intermediate temperatures (235C). However, at the temperature that CDP begins to exhibit high protonic conductivity, it begins to chemically decompose in the absence of humidity. Silicon dioxide (SiO$_{\mathrm{2}})$ is known for its hygroscopic properties and has been used in several applications where adsorption of water is desired. CDP was prepared and characterized with powder x-ray diffraction. Composites of 0.8CsH$_{\mathrm{2}}$PO$_{\mathrm{4}}$/0.2SiO$_{\mathrm{2}}$ were synthesized by mechanically dry mixing CDP with silica nano-powder. Electrochemical impedance spectroscopy was carried out over the span of 10 hours at isotherm (260C) under both dry and humid conditions for all pellet samples. After 10 hours, conductivity values of pure CDP measured at 6.18x10$^{\mathrm{-5\thinspace }}$S cm$^{\mathrm{-1}}$ in dry conditions and 8.37x10$^{\mathrm{-4}}$ S cm$^{\mathrm{-1}}$ in humidity. The composite demonstrated conductivity at 1.768x10$^{\mathrm{-3}}$ S cm$^{\mathrm{-1}}$ and 2.69x10$^{\mathrm{-3\thinspace }}$S cm$^{\mathrm{-1}}$ in dry and humidity conditions, respectively. [Preview Abstract] |
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F1.00031: Neutrosophic Duplet Structures Florentin Smarandache Let $U$ be a universe of discourse, and a set $A$ included in $U$, endowed with a law \begin{figure}[htbp] \centerline{\includegraphics[width=0.09in,height=0.22in]{230620171.eps}} \label{fig1} \end{figure} $_{\mathrm{\ast }}$ that is well-defined. We say that \textit{\textless a, neut(a)\textgreater }, where \textit{a, neut(a) }$\in A$ is a \textbf{Neutrosophic Duplet }if: 1) \textit{neut(a)} is different from the unitary element of$ A$ with respect to the law $*$ (if any); 2) \textit{a*neut(a) }$=$\textit{ neut(a)*a }$= a$; 3) there is no \textit{anti(a)} $\in A$ such that \textit{a*anti(a) }$=$\textit{ anti(a)*a }$=$\textit{ neut(a). } \textbf{Neutrosophic Duplet Structures} are structures defined on the sets of neutrosophic duplets. Their applications in the physical world are investigated. [Preview Abstract] |
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