Low Mach Number Fluctuating Hydrodynamics Of Diffusively Mixing Fluids,
2014
New York University
Low Mach Number Fluctuating Hydrodynamics Of Diffusively Mixing Fluids, Aleksandar Donev, Andy J. Nonaka, Yifei Sun, Thomas Fai, Alejandro Garcia, John B. Bell
Faculty Publications
We formulate low Mach number fluctuating hydrodynamic equations appropriate for modeling diffusive mixing in isothermal mixtures of fluids with different density and transport coefficients. These equations eliminate the fast isentropic fluctuations in pressure associated with the propagation of sound waves by replacing the equation of state with a local thermodynamic constraint. We demonstrate that the low Mach number model preserves the spatio-temporal spectrum of the slower diffusive fluctuations. We develop a strictly conservative finite-volume spatial discretization of the low Mach number fluctuating equations in both two and three dimensions. We construct several explicit Runge-Kutta temporal integrators that strictly maintain the …
Radiographic Image Quality Enhancement By The Use Of Copper Filters,
2014
Sandia National Laboratory
Radiographic Image Quality Enhancement By The Use Of Copper Filters, Timothy T. Sakogawa, Bernice Mills
STAR Program Research Presentations
In x-radiography, filters are often used in order to improve the overall image quality. Filters achieve this by making the x-ray beam have less energy spread, resulting in a cleaner image. Step wedges of different materials were used to compare radiographic density with and without a copper filter to identify the effect of the copper filter at different energies and exposure times. The step wedges used were CRS 1018 (cold rolled steel), Stainless Steel 304L, Al 1100, Al 6061 T6, titanium, copper, PTFE (polytetrafluoroethylene or Teflon), brass, carbon, magnesium, phenolic, tungsten, and tantalum. Out of the 14 step wedges tested, …
Investigation Of The Structure Of The Few Body Kaonic Nuclei Using The Method Of Hyperspherical Functions In Momentum Space,
2014
CUNY New York City College of Technology
Investigation Of The Structure Of The Few Body Kaonic Nuclei Using The Method Of Hyperspherical Functions In Momentum Space, Roman Ya. Kezerashvili, Shalva M. Tsiklauri
Publications and Research
The kaonic clusters KNN and KNNN are studied within the method of hyperspherical functions in the momentum representation. Binding energies and widths of three- and four-body nuclear quasibound states are calculated by employing realistic NN potentials and the energy dependent chiral KN interaction, as well as a phenomenological KN potential. The comparison of the results of calculations obtained in the framework of the variational method, Faddeev, Faddeev-Yakubovsky equations, and method of hyperspherical functions in configuration space are discussed.
Normal Modes Of A Small Gamelan Gong,
2014
Massey University
Normal Modes Of A Small Gamelan Gong, Robert Perrin, Daniel Elford, Luke Chambers, Gerry M. Swallowe, Thomas R. Moore, Sinin Hamdan, Benjamin J. Halkon
Faculty Publications
Studies have been made of the normal modes of a 20.7 cm diameter steel gamelan gong. A finite-element model has been constructed and its predictions for normal modes compared with experimental results obtained using electronic speckle pattern interferometry. Agreement was reasonable in view of the lack of precision in the manufacture of the instrument. The results agree with expectations for an axially symmetric system subject to small symmetry breaking. The extent to which the results obey Chladni's law is discussed. Comparison with vibrational and acoustical spectra enabled the identification of the small number of modes responsible for the sound output …
Chirally Sensitive Electron-Induced Molecular Breakup And The Vester-Ulbricht Hypothesis,
2014
University of Nebraska-Lincoln
Chirally Sensitive Electron-Induced Molecular Breakup And The Vester-Ulbricht Hypothesis, J. M. Dreiling, Timothy J. Gay
Timothy J. Gay Publications
We have studied dissociative electron attachment in sub-eV collisions between longitudinally polarized electrons and chiral bromocamphor molecules. For a given target enantiomer, the dissociative Br anion production depends on the helicity of the incident electrons, with an asymmetry that depends on the electron energy and is of order 3 × 10−4. The existence of chiral sensitivity in a well-defined molecular breakup reaction demonstrates the viability of the Vester-Ulbrict hypothesis, namely, that the longitudinal polarization of cosmic beta radiation was responsible for the origins of biological homochirality.
Spin Density Waves In Periodically Strained
Graphene Nanoribbons,
2014
University of Nebraska at Omaha
Spin Density Waves In Periodically Strained Graphene Nanoribbons, Nabil M. Al-Aqtash, Renat F. Sabirianov
Nebraska Center for Materials and Nanoscience: Faculty Publications
Zigzag graphene nanoribbons (ZGNRs) are antiferromagnetic in the ground state with zero net magnetization due to the compensation of contributions from opposite edges. Uniform deformations (both shear and axial) do not produce magnetization due to symmetry restrictions. However, we report the results of first-principles calculations that predict the induction of spin density waves (SDWs) in ZGNRs under non-uniform periodic strain. Using the density functional theory (DFT) method, we show that a sinusoidal magnetization variation along the axis of the ribbon occurs under a sinusoidal transversal shear strain. SDWs appear due to the presence of a strain gradient that induced asymmetry …
Momentum And Spin In Entropic Quantum Dynamics,
2014
University at Albany, State University of New York
Momentum And Spin In Entropic Quantum Dynamics, Shahid Nawaz
Legacy Theses & Dissertations (2009 - 2024)
We study quantum theory as an example of entropic inference. Our goal is to remove conceptual difficulties that arise in quantum mechanics. Since probability is a common feature of quantum theory and of any inference problem, we briefly introduce probability theory and the entropic methods to update probabilities when new information becomes available. Nelson's stochastic mechanics and Caticha's derivation of quantum theory are discussed in the subsequent chapters. Our first goal is to understand momentum and angular momentum within an entropic dynamics framework and to derive the corresponding uncertainty relations. In this framework momentum is an epistemic concept -- it …
“Spaghetti” Design For Gravitational Wave Superconducting Antenna,
2014
Chapman University
“Spaghetti” Design For Gravitational Wave Superconducting Antenna, Armen Gulian, J Foreman, Vahan Nikoghosyan, Shmuel Nussinov, Louis Sica, Jeff Tollaksen
Mathematics, Physics, and Computer Science Faculty Articles and Research
A new concept for detectors of gravitational wave radiation is discussed. Estimates suggest that strain sensitivity essentially better than that of the existing devices can be achieved in the wide frequency range. Such sensitivity could be obtained with devices about one meter long. Suggested device consists of multi-billion bimetallic superconducting wires ("spaghettis") and requires cryogenic operational temperatures (~0.3K in the case considered).
Comparison Of The Sharpness Of Tungsten Field Emission Tips From Traditional Electrical Characterization To Tip Geometries Imaged By Scanning Electron Microscopy,
2014
Hamline University
Comparison Of The Sharpness Of Tungsten Field Emission Tips From Traditional Electrical Characterization To Tip Geometries Imaged By Scanning Electron Microscopy, Emma C. Reeves
Departmental Honors Projects
Using field emission data obtained from 11 etched Tungsten successful field emission tips of radius about 20 to 100 nanometers, FN type linear models were compared. The emission tip radii were determined using an iteration method derived from the modified FN linear equation. In addition, Scanning Electron Microscopy images of 5 successful emitters were obtained. These images were fit to a circular model to estimate the actual radius and compared to empirically predicted radius values. A hyperbolic model was further fit to the images and the circle of similar apex curvature was derived. A method for calculating the electric field …
Quantum Non-Locality Vs. Quasi-Local Measurement In The Conditions Of The Aharonov-Bohm Effect,
2014
Chapman University
Quantum Non-Locality Vs. Quasi-Local Measurement In The Conditions Of The Aharonov-Bohm Effect, Armen Gulian
Mathematics, Physics, and Computer Science Faculty Articles and Research
Theoretical explanation of the Meissner effect involves proportionality between current density and vector potential, which has many deep consequences. As noticed by de Gennes, superconductors in a magnetic field "find an equilibrium state where the sum of kinetic and magnetic energies is minimum" and this state "corresponds to the expulsion of the magnetic field". This statement still leaves an open question: from which source is the superconducting current acquiring its kinetic energy? A naïve answer, perhaps, is from the energy of the magnetic field. However, one can consider situations (Aharonov-Bohm effect), where the classical magnetic field is locally absent in …
The Spin State Of A Molecular Adsorbate Driven By
The Ferroelectric Substrate Polarization†,
2014
University of Nebraska-Lincoln
The Spin State Of A Molecular Adsorbate Driven By The Ferroelectric Substrate Polarization†, Xin Zhang, Tatiana Palamarciuc, Jean-François Létard, Patrick Rosa, Eduardo Vega Lozada, Fernand Torres, Luis G. Rosa, Bernard Doudin, Peter A. Dowben
Peter Dowben Publications
The spin state of [Fe(H2B(pz)2)2(bipy)] thin films is mediated by changes in the electric field at the interface of organic ferroelectric polyvinylidene fluoride with trifluoroethylene (PVDF–TrFE). Signatures of the molecular crossover transition are evident in changes in the unoccupied states and the related shift from diamagnetic to paramagnetic characteristics. This may point the way to the molecular magneto-electric effect on devices.
Positive Exchange Bias In Epitaxial Permalloy/Mgo Integrated
With Si (100),
2014
Army Research Office, North Carolina State University
Positive Exchange Bias In Epitaxial Permalloy/Mgo Integrated With Si (100), S. S. Rao, J. T. Prater, Fan Wu, S. Nori, D. Kumar, Lanping Yue, Sy_Hwang Liou, Jagdish Narayan
Sy-Hwang Liou Publications
In magnetic random access memory (MRAM) devices, soft magnetic thin film elements such as permalloy (Py) are used as unit cells of information. The epitaxial integration of these elements with the technologically important substrate Si (100) and a thorough understanding of their magnetic properties are critical for CMOS-based magnetic devices. We report on the epitaxial growth of Ni82.5Fe17.5 (permalloy, Py) on Si (100) using a TiN/MgO buffer layer. Initial stages of growth are characterized by the formation of discrete islands that gradually merge into a continuous film as deposition times are extended. Interestingly, we find that the …
An Investigation Of Nurbs-Based Deformable Image Registration,
2014
Virginia Commonwealth University
An Investigation Of Nurbs-Based Deformable Image Registration, Travis J. Jacobson
Theses and Dissertations
Deformable image registration (DIR) is an essential tool in medical image processing. It provides a means to combine image datasets, allowing for intra-subject, inter-subject, multi-modality, and multi-instance analysis, as well as motion detection and compensation. One of the most popular DIR algorithms models the displacement vector field (DVF) as B-splines, a sum of piecewise polynomials with coefficients that enable local shape control. B-splines have many advantageous properties in the context of DIR, but they often struggle to adequately model steep local gradients and discontinuities. This dissertation addresses that limitation by proposing the replacement of conventional B-splines with a generalized formulation …
Finite Density Qed At Strong Magnetic Field,
2014
University of Texas at El Paso
Finite Density Qed At Strong Magnetic Field, Paul Lee Springsteen
Open Access Theses & Dissertations
In this Thesis we study the effect of a dense medium on the quantum properties of a relativistic electron-positron plasma under a magnetic field. From the calculation of the photon polarization operator depending on temperature, chemical potential, and the magnetic field; we study how the electric susceptibility of the strongly magnetized plasma is charged with temperature and density. In the same manner we study the dependence of the Debye mass with density. Then we investigated the phenomenon of magnetic catalysis of chiral symmetry breaking for a dense medium. We found that there exist a critical value of the chemical potential …
Three‐Dimensional Brain Mri For Dbs Patients Within Ultra‐Low Radiofrequency Power Limits,
2014
CUNY New York City College of Technology
Three‐Dimensional Brain Mri For Dbs Patients Within Ultra‐Low Radiofrequency Power Limits, Subhendra N. Sarkar, Efstathios Papavassiliou, David Hackney, David Alsop, Ananth Madhuranthakam, Ludy Shih, Reed Busse, Susan Laruche, Rafeeque Bhadelia
Publications and Research
Background: For patients with deep brain stimulators (DBS), local absorbed radiofrequency (RF) power is unknown and is much higher than what the system estimates. We developed a comprehensive, highquality brain magnetic resonance imaging (MRI) protocol for DBS patients utilizing three-dimensional (3D) magnetic resonance sequences at very low RF power. Methods: Six patients with DBS were imaged (10 sessions) using a transmit/receive head coil at 1.5 Tesla with modified 3D sequences within ultra-low specific absorption rate (SAR) limits (0.1 W/kg) using T2, fast fluid-attenuated inversion recovery (FLAIR) and T1- weighted image contrast. Tissue signal and tissue contrast from the low-SAR images …
Quantum Harmonic Oscillator With Superoscillating Initial Datum,
2014
Chapman University
Quantum Harmonic Oscillator With Superoscillating Initial Datum, Roman V. Buniy, Fabrizio Colombo, Irene Sabadini, Daniele C. Struppa
Mathematics, Physics, and Computer Science Faculty Articles and Research
In this paper, we study the evolution of superoscillating initial data for the quantum driven harmonic oscillator. Our main result shows that superoscillations are amplified by the harmonic potential and that the analytic solution develops a singularity in finite time. We also show that for a large class of solutions of the Schrodinger equation, superoscillating behavior at any given time implies superoscillating behavior at any other time.
Observation Of A Quantum Cheshire Cat In A Matter-Wave Interferometer Experiment,
2014
Vienna University of Technology
Observation Of A Quantum Cheshire Cat In A Matter-Wave Interferometer Experiment, Tobias Denkmayr, Hermann Geppert, Stephan Sponar, Hartmut Lemmel, Alexandre Matzkin, Jeff Tollaksen, Yuji Hasegawa
Mathematics, Physics, and Computer Science Faculty Articles and Research
From its very beginning, quantum theory has been revealing extraordinary and counter-intuitive phenomena, such as wave-particle duality, Schrodinger cats and quantum non-locality. Another paradoxical phenomenon found within the framework of quantum mechanics is the 'quantum Cheshire Cat': if a quantum system is subject to a certain pre- and postselection, it can behave as if a particle and its property are spatially separated. It has been suggested to employ weak measurements in order to explore the Cheshire Cat's nature. Here we report an experiment in which we send neutrons through a perfect silicon crystal interferometer and perform weak measurements to probe …
The Underlying Physiology Of Arterial Pulse Wave Morphology In Spatial Domain,
2013
University of Port Harcourt
The Underlying Physiology Of Arterial Pulse Wave Morphology In Spatial Domain, Nzerem F. Egenti, Alozie H. Nkechi
Applications and Applied Mathematics: An International Journal (AAM)
Cardio-vascular events are among the world’s leading causes of morbidity and mortality. Most postulates suppose that culinary delights can be implicated in incidences of cardio-vascular diseases. This school of thought holds well in many respects. Much as the truistic value of the said school is acknowledged, we conceived of physiological disposition as an endogenous dominant factor in the events being considered, whereas culinary measures constitute an exogenous contributory factor. In this work we aimed at studying the effects of distance (stature) on pulse waveforms. Certain elements of our study showed that pulse wavelength was dominant in prescribing cardio-vascular physiology.
Viscosity Dependence Of Faraday Wave Formation Thresholds,
2013
California Polytechnic State University - San Luis Obispo
Viscosity Dependence Of Faraday Wave Formation Thresholds, Lisa Michelle Slaughter
Physics
This experiment uses an electromagnetic shaker to produce standing wave patterns on the surface of a vertically oscillating sample of silicon liquid. These surface waves, known as Faraday waves, form shapes such as squares, lines, and hexagons. They are known to be dependent upon the frequency and amplitude of the forcing as well as on the viscosity and depth of the liquid in the dish. At a depth of 4mm and for various silicon liquids having kinematic viscosities of 10, 20, and 38 cSt, we determined the acceleration at which patterns form for frequencies between 10 and 60 Hz. For …
Dispersion Of A Solute In Hartmann Two-Fluid Flow Between Two Parallel Plates,
2013
Gulbarga University
Dispersion Of A Solute In Hartmann Two-Fluid Flow Between Two Parallel Plates, J. P. Kumar, J. C. Umavathi
Applications and Applied Mathematics: An International Journal (AAM)
The paper presents an analytical solution for the dispersion of a solute in a conducting immiscible fluid flowing between two parallel plates in the presence of a transverse magnetic field. The fluids in both the regions are incompressible, electrically conducting and the transport properties are assumed to be constant. The channel walls are assumed to be electrically insulating. Separate solutions for each fluid are obtained and these solutions are matched at the interface using suitable matching conditions. The results are tabulated for various values of viscosity ratio, pressure gradient and Hartman number on the effective Taylor dispersion coefficient and volumetric …
