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Articles 1 - 30 of 30873

Full-Text Articles in Physical Sciences and Mathematics

Substitutional And Interstitial Doping In Laco5 System For The Development Of Hard Magnetic Properties: A First Principles Study, Huseyin Ucar, Renu Choudhary, Durga Paudyal Sep 2020

Substitutional And Interstitial Doping In Laco5 System For The Development Of Hard Magnetic Properties: A First Principles Study, Huseyin Ucar, Renu Choudhary, Durga Paudyal

Ames Laboratory Accepted Manuscripts

We investigate here the changes in the electronic structure at the transition metal sites of the RE-TM5 structure (RE = Rare Earth, TM = Transition Metal) while doping the interstitial sites with nitrogen. LaCo5 compound is taken as the baseline compound owing to its critically needed intrinsic magnetic properties such as magneto-crystalline anisotropy energy (MAE) of ≈5 meV/fu [1] due to the contributions from the cobalt network. In addition, because of the lack of 4f electrons in lanthanum, complications originating from the treatment of the 4f localized electrons are absent in this compound; making it an ideal reference material to all ...


At The Interface Of Algebra And Statistics, Tai-Danae Bradley Jun 2020

At The Interface Of Algebra And Statistics, Tai-Danae Bradley

All Dissertations, Theses, and Capstone Projects

This thesis takes inspiration from quantum physics to investigate mathematical structure that lies at the interface of algebra and statistics. The starting point is a passage from classical probability theory to quantum probability theory. The quantum version of a probability distribution is a density operator, the quantum version of marginalizing is an operation called the partial trace, and the quantum version of a marginal probability distribution is a reduced density operator. Every joint probability distribution on a finite set can be modeled as a rank one density operator. By applying the partial trace, we obtain reduced density operators whose diagonals ...


Generalized Four-Dimensional Effective Hadronic Supersymmetry Based On Quantum Chromodynamics (Qcd), Enxi Yu Jun 2020

Generalized Four-Dimensional Effective Hadronic Supersymmetry Based On Quantum Chromodynamics (Qcd), Enxi Yu

All Dissertations, Theses, and Capstone Projects

New discovery in multiple laboratories around the globe has shown a supersymmetry between hadrons—baryons and mesons. In order to generalize the phenomenological hadronic supersymmetry, the spin-flavor SU(6) symmetry need an extension. This thesis present how we can extend SU(6) symmetry so that hadronic supersymmetry can be included. In the future, this extension can be also applied to pentaquark and tetraquark bags, for which there is an ongoing research in laboratories.


Proton Pumping Mechanism In Cytochrome C Oxidase, Xiuhong Cai Jun 2020

Proton Pumping Mechanism In Cytochrome C Oxidase, Xiuhong Cai

All Dissertations, Theses, and Capstone Projects

Cytochrome c Oxidase (CcO), is the terminal electron acceptor in the membrane bound aerobic respiratory chain. It reduces O2 to water. The energy released by this reaction is stored by pumping protons from the high pH, N-side of the membrane to the low pH, P-side. The generated proton gradient provides the motive force for synthesis of ATP by the ATP synthase.

Building a proton gradient across the membrane requires that proton transport must occur along controllable proton pathways to prevent proton leakage to the N-side. It has been suggested that CcO function requires proton transfer channels in both the ...


Small-X Qcd Calculations With A Biased Ensemble, Gary Kapilevich Jun 2020

Small-X Qcd Calculations With A Biased Ensemble, Gary Kapilevich

All Dissertations, Theses, and Capstone Projects

In this dissertation, I will argue that we can study functional fluctuations in unintegrated gluon distributions, in the MV model as well as JIMWLK, using reweighting techniques, which will allow me to calculate QCD observables with "biased ensembles". This technique will enable me to study rare functional configurations of the gluon distributions, that might have been selected for in, for example, the centrality criteria used by the ATLAS and ALICE collaborations. After a review of these techniques, as well as a review of QCD physics at high energy in general, I will use biased ensembles to compute observables in two ...


Generating Entanglement With The Dynamical Lamb Effect, Mirko Amico Jun 2020

Generating Entanglement With The Dynamical Lamb Effect, Mirko Amico

All Dissertations, Theses, and Capstone Projects

According to quantum field theory, the vacuum is filled with virtual particles which can be turned into real ones under the influence of external perturbations. Phenomena of this kind are commonly referred to as quantum vacuum phenomena. Several quantum vacuum phenomena related to the peculiar nature of the quantum vacuum have been predicted, some of which, such as the Lamb shift and the Casimir effect, have been experimentally found. Other examples of quantum vacuum phenomena include the Unruh effect, the dynamical Casimir effect and the dynamical Lamb effect. The dynamical Lamb effect was first predicted by considering the situation of ...


Waiting-Time Paradox In 1922, Naoki Masuda, Takayuki Hiraoka May 2020

Waiting-Time Paradox In 1922, Naoki Masuda, Takayuki Hiraoka

Northeast Journal of Complex Systems (NEJCS)

We present an English translation and discussion of an essay that a Japanese physicist, Torahiko Terada, wrote in 1922. In the essay, he described the waiting-time paradox, also called the bus paradox, which is a known mathematical phenomenon in queuing theory, stochastic processes, and modern temporal network analysis. He also observed and analyzed data on Tokyo City trams to verify the relevance of the waiting-time paradox to busy passengers in Tokyo at the time. This essay seems to be one of the earliest documentations of the waiting-time paradox in a sufficiently scientific manner.


Biological Physics Student Edition 2020: Chapter 1, Philip C. Nelson May 2020

Biological Physics Student Edition 2020: Chapter 1, Philip C. Nelson

Department of Physics Papers

Chapter 1: What the Ancients Knew


Biological Physics Student Edition 2020: Contents And Prefaces, Philip C. Nelson May 2020

Biological Physics Student Edition 2020: Contents And Prefaces, Philip C. Nelson

Department of Physics Papers

Brief Contents; Detailed Contents; To the Student; To the Instructor


Table Of Contents May 2020

Table Of Contents

Journal of the South Carolina Academy of Science

No abstract provided.


Non-Equilibrium Growth Of Metal Clusters On A Layered Material: Cu On Mos2, Dapeng Jing, Ann Lii-Rosales, King C. Lai, Qiang Li, Jaeyoun Kim, Michael C. Tringides, James W. Evans, Patricia A. Thiel May 2020

Non-Equilibrium Growth Of Metal Clusters On A Layered Material: Cu On Mos2, Dapeng Jing, Ann Lii-Rosales, King C. Lai, Qiang Li, Jaeyoun Kim, Michael C. Tringides, James W. Evans, Patricia A. Thiel

Chemistry Publications

We use a variety of experimental techniques to characterize Cu clusters on bulk MoS2 formed via physical vapor deposition of Cu in ultrahigh vacuum, at temperatures ranging from 300 K to 900 K. We find that large facetted clusters grow at elevated temperatures, using high Cu exposures. The cluster size distribution is bimodal, and under some conditions, large clusters are surrounded by a denuded zone. We propose that defect-mediated nucleation, and coarsening during deposition, are both operative in this system. At 780 K, a surprising type of facetted cluster emerges, and at 900 K this type predominates: pyramidal clusters with ...


D-Orbital Occupancy Of Transition Metal Oxides By X-Ray Absorption Near Edge Structure (Xanes), Eric Kurywczak May 2020

D-Orbital Occupancy Of Transition Metal Oxides By X-Ray Absorption Near Edge Structure (Xanes), Eric Kurywczak

Seton Hall University Dissertations and Theses (ETDs)

XANES L2 and L3-edge X-Ray Absorption Near Edge Spectra (XANES) for 4d and 5d row transition metals (TM) oxides are assumed to be directly reflecting unoccupied d orbitals influenced by the local symmetry of the metal ion. XANES L2- and L3-edge data analysis through non-linear curve fitting allows for a unique, efficient look at the structural eccentricities of transition metal oxides. In this way it is possible to determine the oxidation state of a material as well as its site symmetry. We have used non-linear least-squares fitting across the near-edge region of ...


Parameter Identifiability And Estimation In A 1d Cardiovascular Fluid Dynamics Model, Mitchel J. Colebank May 2020

Parameter Identifiability And Estimation In A 1d Cardiovascular Fluid Dynamics Model, Mitchel J. Colebank

Biology and Medicine Through Mathematics Conference

No abstract provided.


Emergence, Mechanics, And Development: How Behavior And Geometry Underlie Cowrie Seashell Form, Michael G. Levy, Michael R. Deweese May 2020

Emergence, Mechanics, And Development: How Behavior And Geometry Underlie Cowrie Seashell Form, Michael G. Levy, Michael R. Deweese

Biology and Medicine Through Mathematics Conference

No abstract provided.


Parameter Estimation For Tear Film Thinning, Rayanne Luke May 2020

Parameter Estimation For Tear Film Thinning, Rayanne Luke

Biology and Medicine Through Mathematics Conference

No abstract provided.


Pressure Tuning Of Structural And Magnetic Transitions In Euag4as2, Sergey L. Bud’Ko, Li Xiang, Chaowei Hu, Bing Shen, Ni Ni, Paul C. Canfield May 2020

Pressure Tuning Of Structural And Magnetic Transitions In Euag4as2, Sergey L. Bud’Ko, Li Xiang, Chaowei Hu, Bing Shen, Ni Ni, Paul C. Canfield

Ames Laboratory Accepted Manuscripts

We report temperature-dependent measurements of ambient-pressure specific heat, magnetic susceptibility, anisotropic resistivity, and thermal expansion as well as in-plane resistivity under pressure up to 20.8 kbar on single crystals of EuAg4As2. Based on thermal expansion and in-plane electrical transport measurements at ambient pressure this compound has two, first-order, structural transitions in the 80–120 K temperature range. Ambient-pressure specific heat, magnetization, and thermal expansion measurements show a cascade of up to seven transitions between 8 and 16 K associated with the ordering of the Eu2+ moments. In-plane electrical transport is able to detect the more prominent of these transitions ...


Supercdms: Energy Calibration Of A Ge Hv Particle Detector, Salamong Xiong, Vuk Mandic, Matthew Fritts, Nicholas Mast, Jacob Nelson May 2020

Supercdms: Energy Calibration Of A Ge Hv Particle Detector, Salamong Xiong, Vuk Mandic, Matthew Fritts, Nicholas Mast, Jacob Nelson

Macalester Journal of Physics and Astronomy

The goal of the SuperCDMS collaboration is to directly detect dark matter. Weakly Interacting Massive Particles (WIMPs) are potential candidates. To detect WIMPs, it is important to be able to predict how a Ge/Si particle detector will respond to a dark matter signal. In particular, it is necessary to calibrate the recoil energy measured by these detectors. This paper presents evidence for dark matter, a description of the detector operation, and procedures used to analyze measured data from a SuperCDMS-HV Ge particle detector using Am-241 and a PuBe neutron source. Due to high event rate, criteria were developed to ...


Calculating Centrality Variables And Geometric Quantities Associated With High Energy Pb+Pb And Au+Au Collisions Using A Monte Carlo Glauber Model, Anya Wolterman May 2020

Calculating Centrality Variables And Geometric Quantities Associated With High Energy Pb+Pb And Au+Au Collisions Using A Monte Carlo Glauber Model, Anya Wolterman

Macalester Journal of Physics and Astronomy

The Glauber model provides insight into the initial state of nuclear collisions by treating them in terms of the interactions between their constituent nucleons, in accordance with theories about the scattering of composite particles. These phenomenological techniques are commonly used to determine various geometric quantities associated with such complex, femtoscopic many-body systems. The Monte Carlo Glauber approach uses a random impact parameter and measured nuclear densities to investigate quantifiable properties like particle multiplicity and average geometric eccentricity for heavy ion collisions. The former involves incorporating a particle production model to plot the total transverse energy or the number of particles ...


Fabrication Of Nanoscale Columnar Diodes By Glancing Angle Deposition, Jacob D. Weightman May 2020

Fabrication Of Nanoscale Columnar Diodes By Glancing Angle Deposition, Jacob D. Weightman

Macalester Journal of Physics and Astronomy

Glancing angle deposition (GLAD) is a process in which thin films are deposited onto a substrate with obliquely incident vapor together with precisely controlled azimuthal substrate rotation. Ballistic shadowing effects due to the oblique incidence produce nanoscale structures, and a variety of feature shapes, including tilted columns, helices, and vertical columns can be achieved by varying the azimuthal rotation during the deposition process. Due to this control of morphology and the compatibility of the process with a wide variety of materials, GLAD films have found applications in a variety of fields including sensing, photonics, photovoltaics, and catalysis, where they are ...


The Leoncino Dwarf: A Neutral Hydrogen Analysis Of Agc 198691 And Its Extremely Metal-Poor Environment, Tylyn Page May 2020

The Leoncino Dwarf: A Neutral Hydrogen Analysis Of Agc 198691 And Its Extremely Metal-Poor Environment, Tylyn Page

Macalester Journal of Physics and Astronomy

Studies of low-mass galaxies are important for populating the low-mass ends of funda- mental physical relations. Extremely metal-poor (XMP) galaxies are low-mass galaxies with gas-phase oxygen abundances of 12+log(O/H) ≤ 7.35 ( 1/20 Z⊙), and are especially interesting as proxies for studying the distant past, as their chemical makeup resembles those of galaxies in the early universe. AGC 198691, referred to as the Leoncino Dwarf, was discovered through the Arecibo Legacy Fast ALFA (ALFALFA) survey and found to have an oxygen abundance of less than 3% Z⊙. Presented here are the results of recent Karl G. Jansky ...


Large Scale Grid Integration Of Wind And Solar Power With Storage, Nicholas Moore May 2020

Large Scale Grid Integration Of Wind And Solar Power With Storage, Nicholas Moore

Macalester Journal of Physics and Astronomy

The current energy grid in the United States is dominated by carbon intense energy generation methods that are based on production when and where it is required. However, solar and wind power have proved themselves as the most promising carbon free energy generation sources. Due to the unpredictable and uncontrollable nature of energy production from solar and wind, large scale integration of these resources into the electric grid will require robust storage capacity. In this project, we model the energy grid of the Midcontinent Independent System Operator (MISO) energy region with high concentrations of solar and wind power to analyze ...


Deposition Of Tin For Battery And Supercapacitor Electrodes For Energy Storage, Kieran M. Liming May 2020

Deposition Of Tin For Battery And Supercapacitor Electrodes For Energy Storage, Kieran M. Liming

Macalester Journal of Physics and Astronomy

Titanium Nitride (TiN) can be sputtered into a thin film, and is a promising component for battery and supercapacitor electrodes. This research explored the relationship between Nitride partial pressure and film characteristics. We sputtered TiN into thin films in a low vacuum environment at tempuratures of approximately 70o C. Most films were deposited over the course of one hour including a five minute presputtering period where the substrate was covered. We found that film thickness, system voltage, and film restivitiy to be a function of N2 partial pressure.


Searching For Doublet Vectorlike Leptons Using The Atlas Particle Detector, Brynn Keller May 2020

Searching For Doublet Vectorlike Leptons Using The Atlas Particle Detector, Brynn Keller

Macalester Journal of Physics and Astronomy

Vectorlike leptons are a simple extension of the standard model, akin to a fourth family of leptons. This paper describes aspects of the preparation for a search for VLLs at an ATLAS particle collider. During this research, signal and control regions were determined with use of a Monte Carlo simulation in order to best estimate where to measure different kinds of background and where to search for a potential signal. These signal and control regions were optimized with respect to MET, LT, and number of light and heavy leptons with a goal of a 95\% confidence limit.


A Search For Pulsars Towards The Galactic Center, Jacob W. Hetrick, Kunal Mooley, Preshanth Jagannathan May 2020

A Search For Pulsars Towards The Galactic Center, Jacob W. Hetrick, Kunal Mooley, Preshanth Jagannathan

Macalester Journal of Physics and Astronomy

We present observations from two separate methods for observing the Galactic Center in an attempt to characterize its pulsar and neutron star populations. A persistent puzzle of the past 20 years has been the lack of pulsar detections towards the Galactic Center, specifically within a few parsecs of the central supermassive black hole Sgr A*. This object is bright in the total intensity of its polarized emission, but is very weakly linearly polarized. We take advantage of these circumstances in an experimental search technique where we utilize the Faraday effect in an attempt to detect high rotation measure (RM) point ...


Modeling Scavenging For A Hydraulic Free-Piston Engine, Nathan Davies May 2020

Modeling Scavenging For A Hydraulic Free-Piston Engine, Nathan Davies

Macalester Journal of Physics and Astronomy

The hydraulic free-piston engine at the University of Minnesota offers a solution to improve the hydraulic efficiency and reduce emission output of off-road vehicles. We developed a MATLAB Simulink model to track the pressure, temperature, and mass profile of the fuel within the cylinder during operation. By varying different initial conditions of our model, we found that a higher intake manifold pressure and larger bottom dead center location results in higher scavenging efficiency. These results can be used to improve the controller of this engine and better maintain stable operation.


Alfalfa Harvest: Hi Imaging And 3d Modeling Of Candidate Local Group Dwarf Galaxies, Lilly Bralts-Kelly, Susie Paine, Elizabeth A. K. Adams, John M. Cannon May 2020

Alfalfa Harvest: Hi Imaging And 3d Modeling Of Candidate Local Group Dwarf Galaxies, Lilly Bralts-Kelly, Susie Paine, Elizabeth A. K. Adams, John M. Cannon

Macalester Journal of Physics and Astronomy

Isolated neutral hydrogen (HI) clouds, or "ultra-compact high-velocity clouds" (UCHVCs), form a small subset of detections by the Arecibo Legacy Fast ALFA (ALFALFA) blind extragalactic survey. These systems, if located within ~1 Mpc, would populate the lowest-mass end of the HI mass function. Subsequent optical imaging has revealed that some of these UCHVCs harbor associated (thought sparse) stellar populations, suggesting that they may be some of the most extreme galaxies known in the Local Volume, with properties akin to ultra-faint dwarf galaxies but with significant neutral gas reservoirs. In this work, we investigate the neutral hydrogen properties of six UCHVC ...


Leoncino And Ugc 5186, Josh Bartz May 2020

Leoncino And Ugc 5186, Josh Bartz

Macalester Journal of Physics and Astronomy

AGC 198691 is commonly known as the Leoncino Dwarf and is one of the most metal poor galax- ies known. An Arecibo observation in 2011 first suggested that Leoncino could be gravitationally interacting with its neighbor UGC 5186. In this paper new VLA data is used to examine the H I com- ponent of both galaxies to determine their gravitational relationship. Although the VLA could not confirm intragalactic gas seen by Aricebo, the H I density and velocity components are strong indirect evidence of gravitational interaction. UGC 5186 has a large gaseous arm reaching in the direction of Leoncino. Additionally ...


Coherent Captain Mills: The Search For Sterile Neutrinos, Ashley Elliott, Jeramy Gordon, Jonah Greenwood, Rachel Lake, Ryder Moreno, Emily Strawn, Kate Walker May 2020

Coherent Captain Mills: The Search For Sterile Neutrinos, Ashley Elliott, Jeramy Gordon, Jonah Greenwood, Rachel Lake, Ryder Moreno, Emily Strawn, Kate Walker

Discovery Day - Prescott

The observation of neutrino oscillations confirms that the active neutrinos (νe, νμ, ντ) are comprised of three mass eigenstates with Δm2 values between 10-3 to 10-5 eV2 . However, a persistent phenomenon has been observed at LSND, MiniBooNE and other shortbaseline experiments (SBE) where Δm2 ~ 1eV2 and is not compatible with the current mixing between mass eigenstates. However, a 4th neutrino, a sterile neutrino (νs) that doesn’t participate in weak interactions could explain the phenomena observed as SBE’s. An experiment has been constructed at TA-53 at Los Alamos National Laboratory to investigate this large Δm2 ~ 1eV2 and determine conclusively ...


Heel Down And Toe-Off Time Measured With Ultrasonic Doppler System And Force Plate Sensor, Sabin Timsina May 2020

Heel Down And Toe-Off Time Measured With Ultrasonic Doppler System And Force Plate Sensor, Sabin Timsina

Honors Theses

Collie Box is a medical device that measures the gait parameters of the person walk- ing in front of it. This device uses the Ultrasonic Doppler system to extract the heel-contact and toe-off times of a person walking within the range of 2-10 meters. These times are used to determine the leg’s swing phase and double stance times. The ultrasonic transducer of 10mm diameter is driven at 40kHz. At the time of the heel-contact and toe-off, foot velocity is zero while the torso part of the human body is still in motion. The wide directivity of 10mm diameter ultrasonic ...


Investigatin Actin-Myosin Mechanics To Model Heart Disease Using Fluorescence Microscopy And Optical Trapping, Justin Edward Reynolds May 2020

Investigatin Actin-Myosin Mechanics To Model Heart Disease Using Fluorescence Microscopy And Optical Trapping, Justin Edward Reynolds

Honors Theses

Hypertrophic cardiomyopathy (HCM) is a hereditary disease in which the myocardium becomes hypertrophied, making it more difficult for the heart to pump blood. HCM is commonly caused by a mutation in the β-cardiac myosin II heavy chain. Myosin is a motor protein that facilitates muscle contraction by converting chemical energy from ATP hydrolysis into mechanical work and concomitantly moving along actin filaments. Optical tweezers have been used previously to analyze single myosin biophysical properties; however, myosin does not work as a single unit within the heart. Multiple myosin interacts to displace actin filaments and do not have the same properties ...