-STABILITY AND VORTEX MOTION IN TYPE II SUPERCONDUCTORS
Spirn, Daniel
-STABILITY AND VORTEX MOTION IN TYPE II SUPERCONDUCTORS MATTHIAS KURZKE AND DANIEL SPIRN Abstract. 1. Introduction 1.1. Physical background. The evolution of a superconducting material is usu- ally of the magnetic field and the electric field potential for a superconducting sample R2 . The parameter
Vortex stabilized electron beam compressed fusion grade plasma
Hershcovitch, Ady [Brookhaven National Lab. (BNL), Upton, NY (United States). Collider-Accelerator Dept.
2014-03-19T23:59:59.000Z
Most inertial confinement fusion schemes are comprised of highly compressed dense plasmas. Those schemes involve short, extremely high power, short pulses of beams (lasers, particles) applied to lower density plasmas or solid pellets. An alternative approach could be to shoot an intense electron beam through very dense, atmospheric pressure, vortex stabilized plasma.
Spectral Techniques for Solving PDE Stability Model of Vortex Rope
Bistrian, Diana Alina
2012-01-01T23:59:59.000Z
In this paper spectral methods are applied to investigate the hydrodynamic instability of swirling flow with application to Francis hydraulic turbine. Spectral methods imply representing the problem solution as truncated series of smooth global functions. An L2 - projection and the collocation methods are developed assessing both analytically methodology and computational techniques using symbolic and numerical conversions. Remarks concerning the efficiency and the accuracy of each method in this case are presented. The model of the trailing vortex is used to validate the numerical algorithms with existing results in the literature. All the results are compared to existing ones and they prove to agree quite well. The advantages of using this methods in flow control problems are pointed out.
Hardee, Harry C. (Albuquerque, NM)
1991-01-01T23:59:59.000Z
A rotary pneumatic valve which is thrust balanced and the pneumatic pressure developed produces only radial loads on the valve cylinder producing negligible resistance and thus minimal torque on the bearings of the valve. The valve is multiplexed such that at least two complete switching cycles occur for each revolution of the cylinder spindle.
Pneumatic battery : a chemical alternative to pneumatic energy storage
Kojimoto, Nigel (Nigel C.)
2012-01-01T23:59:59.000Z
Pneumatic power is traditionally provided by compressed air contained in a pressurized vessel. This method of energy storage is analogous to an electrical capacitor. This study sought to create an alternative pneumatic ...
Neuhaus, J.E.
1992-10-13T23:59:59.000Z
A soil removal tool is provided for removing radioactive soil, rock and other debris from the bottom of an excavation, while permitting the operator to be located outside of a containment for that excavation. The tool includes a fixed jaw, secured to one end of an elongate pipe, which cooperates with a movable jaw pivotably mounted on the pipe. Movement of the movable jaw is controlled by a pneumatic cylinder mounted on the pipe. The actuator rod of the pneumatic cylinder is connected to a collar which is slidably mounted on the pipe and forms part of the pivotable mounting assembly for the movable jaw. Air is supplied to the pneumatic cylinder through a handle connected to the pipe, under the control of an actuator valve mounted on the handle, to provide movement of the movable jaw. 3 figs.
Neuhaus, John E. (Newport News, VA)
1992-01-01T23:59:59.000Z
A soil removal tool is provided for removing radioactive soil, rock and other debris from the bottom of an excavation, while permitting the operator to be located outside of a containment for that excavation. The tool includes a fixed jaw, secured to one end of an elongate pipe, which cooperates with a movable jaw pivotably mounted on the pipe. Movement of the movable jaw is controlled by a pneumatic cylinder mounted on the pipe. The actuator rod of the pneumatic cylinder is connected to a collar which is slidably mounted on the pipe and forms part of the pivotable mounting assembly for the movable jaw. Air is supplied to the pneumatic cylinder through a handle connected to the pipe, under the control of an actuator valve mounted on the handle, to provide movement of the movable jaw.
Pneumatic conveyance apparatus and process
Heckendorn, Frank M.; Matzolf, Athneal D.; Hera, Kevin R.
2010-05-04T23:59:59.000Z
A pneumatic nozzle capable of removing dry solid debris, liquids, and mixtures of solid and liquid waste is provided. The pneumatic nozzle uses a pressurized gas stream to push materials through the nozzle. The force of a pressurized gas stream provides a partial vacuum to allow material to be introduced into an opening of a nozzle via a slight suction force. Thereafter, individual particles and materials introduced into the pneumatic nozzle are pushed by a stream of pressurized gas through the nozzle.
All-optical discrete vortex switch
Desyatnikov, Anton S. [Nonlinear Physics Center, Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200 (Australia); Dennis, Mark R. [H. H. Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom); Ferrando, Albert [Interdisciplinary Modeling Group, InterTech and Departament d'Optica, Universitat de Valencia, E-46100 Burjassot (Spain)
2011-06-15T23:59:59.000Z
We introduce discrete vortex solitons and vortex breathers in circular arrays of nonlinear waveguides. The simplest vortex breather in a four-waveguide coupler is a nonlinear dynamic state changing its topological charge between +1 and -1 periodically during propagation. We find the stability domain for this solution and suggest an all-optical vortex switching scheme.
Sliding pressure control valve for pneumatic hammer drill
Polsky, Yarom (Albuquerque, NM)
2011-08-30T23:59:59.000Z
A pneumatic device control apparatus and method comprising a ported valve slidably fitted over a feed tube of the pneumatic device, and using a compliant biasing device to constrain motion of the valve to provide asymmetric timing for extended pressurization of a power chamber and reduced pressurization of a return chamber of the pneumatic device. The pneumatic device can be a pneumatic hammer drill.
Vortex methods and vortex statistics
Chorin, A.J.
1993-05-01T23:59:59.000Z
Vortex methods originated from the observation that in incompressible, inviscid, isentropic flow vorticity (or, more accurately, circulation) is a conserved quantity, as can be readily deduced from the absence of tangential stresses. Thus if the vorticity is known at time t = 0, one can deduce the flow at a later time by simply following it around. In this narrow context, a vortex method is a numerical method that makes use of this observation. Even more generally, the analysis of vortex methods leads, to problems that are closely related to problems in quantum physics and field theory, as well as in harmonic analysis. A broad enough definition of vortex methods ends up by encompassing much of science. Even the purely computational aspects of vortex methods encompass a range of ideas for which vorticity may not be the best unifying theme. The author restricts himself in these lectures to a special class of numerical vortex methods, those that are based on a Lagrangian transport of vorticity in hydrodynamics by smoothed particles (``blobs``) and those whose understanding contributes to the understanding of blob methods. Vortex methods for inviscid flow lead to systems of ordinary differential equations that can be readily clothed in Hamiltonian form, both in three and two space dimensions, and they can preserve exactly a number of invariants of the Euler equations, including topological invariants. Their viscous versions resemble Langevin equations. As a result, they provide a very useful cartoon of statistical hydrodynamics, i.e., of turbulence, one that can to some extent be analyzed analytically and more importantly, explored numerically, with important implications also for superfluids, superconductors, and even polymers. In the authors view, vortex ``blob`` methods provide the most promising path to the understanding of these phenomena.
Chorin, A.J. [California Univ., Berkeley, CA (United States). Dept. of Mathematics]|[Lawrence Berkeley Lab., CA (United States)
1993-06-01T23:59:59.000Z
Vortex methods originated from the observation that in incompressible inviscid flow vorticity (or, more accurately, circulation) is a conserved quantity, as can be readily deduced from the absence of tangential stresses. Thus, if the vorticity is known at time t=0, one can find the flow at a later time by simply following the vorticity. In this narrow context, a vortex method is a numerical method that follows vorticity. The author restricts himself in these lectures to a special class of numerical vortex methods, those that are based on a Lagrangian transport of vorticity in hydrodynamics by smoothed particles (blobs) and those whose analysis contributes to the understanding of blob methods. Blob methods started in the 1930`s.
Tomoya Isoshima; Kazushige Machida
1999-02-27T23:59:59.000Z
The instability condition of the non-vortex state toward vortex formation is exa mined within the Bogoliubov theory when a Bose-Einstein condensate is under exte rnally forced rotation. The obtained critical angular velocity combined with the previous stability cond itions for a votex yields a detailed phase diagram in the critical velocity vs t he system parameter. This facilitates vortex formation experiments for alkali atom gases confined in a harmonic potential.
MODELING OF HYDRO-PNEUMATIC ENERGY STORAGE USING PUMP TURBINES
Paris-Sud XI, UniversitÃ© de
MODELING OF HYDRO-PNEUMATIC ENERGY STORAGE USING PUMP TURBINES E. Ortego, A. Dazin, G. Caignaert, F. Colas, O. Coutier-Delgosha Abstract: Modelling of a hydro-pneumatic energy storage system is the main demand response strategy. 1 Introduction Energy storage is one of the most exciting solutions considered
Neural Network Control of a Pneumatic Robot Ted Hesselroth
Duckett, Tom
Neural Network Control of a Pneumatic Robot Arm Ted Hesselroth , Kakali Sarkar , P. Patrick van der been employed to control a five-joint pneu- matic robot arm and gripper through feedback from two video cameras. The pneumatically driven robot arm (SoftArm) employed in this inves- tigation shares essential
Development of dense-phase pneumatic transport of coal
Horisaka, S.; Ikemiya, H.; Kajiwara, T. [Sumitomo Metal Industries, Ltd., Kashima, Ibaraki (Japan)
1996-12-31T23:59:59.000Z
Dense phase pneumatic transport system has been developed to reduce entrained particles as is seen in the belt conveyor system. High mass flow rate and dense phase (Loading ratio = 50--100kg-coal/kg-N{sub 2}) transport has been achieved by applying this plug flow system to pneumatic conveying of coal (Average particle diameter = 2.5 mm).
A finite element analysis of pneumatic-tire/sand interactions
Grujicic, Mica
A finite element analysis of pneumatic-tire/sand interactions during off-road vehicle travel M pneumatic tire and sand during off-road vehicle travel. Keywords Finite element analysis, Road vehicles and for other tire/sand combinations. Since the finite element analysis of the tire/sand interaction enables
MHK Technologies/Pneumatically Stabilized Platform PSP | Open Energy
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand Jump to: navigation, searchOfRose Bend < MHK ProjectsFlagshipNAREC <AirOyster
Inline evenflow material distributor for pneumatic material feed systems
Thiry, Michael J. (Oakdale, CA)
2007-02-20T23:59:59.000Z
An apparatus for reducing clogs in a pneumatic material feed line, such as employed in abrasive waterjet machining systems, by providing an evenflow feed of material therethrough. The apparatus preferably includes a hollow housing defining a housing volume and having an inlet capable of connecting to an upstream portion of the pneumatic material feed line, an outlet capable of connecting to a downstream portion of the pneumatic material feed line, and an air vent located between the inlet and outlet for venting excess air pressure out from the housing volume. A diverter, i.e. an impingement object, is located at the inlet and in a path of incoming material from the upstream portion of the pneumatic material feed line, to break up clumps of ambient moisture-ridden material impinging on the diverter. And one or more filter screens is also preferably located in the housing volume to further break up clumps and provide filtering.
Improved vortex reactor system
Diebold, James P. (Lakewood, CO); Scahill, John W. (Evergreen, CO)
1995-01-01T23:59:59.000Z
An improved vortex reactor system for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor.
Houck, Edward D. (Idaho Falls, ID)
1994-01-01T23:59:59.000Z
A fluid transfer system that combines a vortex diode with a jet ejector to transfer liquid from one tank to a second tank by a gas pressurization method having no moving mechanical parts in the fluid system. The vortex diode is a device that has a high resistance to flow in one direction and a low resistance to flow in the other.
COMPARISON OF PNEUMATIC AND HYDRAULIC FRACTURING FOR EMPLACEMENT OF TREATMENT MATERIALS IN LOW
Mark Strong; Craig Sprinkle; Denis Ewing
, Georgia to evaluate the performance of pneumatic and hydraulic frac-turing for emplacement of in situ
A Pneumatic Actuated Microfluidic Beads-Trapping Device
Shao, Guocheng; Cai, Ziliang; Wang, Jun; Wang, Wanjun; Lin, Yuehe
2011-08-20T23:59:59.000Z
The development of a polydimethylsiloxane (PDMS) microfluidic microbeads trapping device is reported in this paper. Besides fluid channels, the proposed device includes a pneumatic control chamber and a beads-trapping chamber with a filter array structure. The pneumatic flow control chamber and the beads-trapping chamber are vertically stacked and separated by a thin membrane. By adjusting the pressure in the pneumatic control chamber, the membrane can either be pushed against the filter array to set the device in trapping mode or be released to set the device in releasing mode. In this paper, a computational fluid dynamics simulation was conducted to optimize the geometry design of the filter array structure; the device fabrication was also carried out. The prototype device was tested and the preliminary experimental results showed that it can be used as a beads-trapping unit for various biochemistry and analytical chemistry applications, especially for flow injection analysis systems.
A real time neural energy management strategy for a hybrid pneumatic engine
Paris-Sud XI, Université de
A real time neural energy management strategy for a hybrid pneumatic engine Guillaume Colin G.bloch@esstin.uhp-nancy.fr} Abstract: Various energy management strategies for a hybrid pneumatic engine are reviewed and a real time Recognition. Keywords: energy management strategy, fuel saving, hybrid vehicle, hybrid pneumatic engine
Mechanical Compliance Control System for A Pneumatic Robot Arm Kouichi Watanabe1
Tachi, Susumu
- 2789 - Mechanical Compliance Control System for A Pneumatic Robot Arm Kouichi Watanabe1 , Hisashi position and posture of the arm. Keywords: Pneumatic actuator, Humanoid robot arm, Compliance control 1 actuators have started gaining attention as robot actuators. We focused on the robot arm using a pneumatic
Improved vortex reactor system
Diebold, J.P.; Scahill, J.W.
1995-05-09T23:59:59.000Z
An improved vortex reactor system is described for affecting fast pyrolysis of biomass and Refuse Derived Fuel (RDF) feed materials comprising: a vortex reactor having its axis vertically disposed in relation to a jet of a horizontally disposed steam ejector that impels feed materials from a feeder and solids from a recycle loop along with a motive gas into a top part of said reactor. 12 figs.
The Holographic Superconductor Vortex
Marc Montull; Alex Pomarol; Pedro J. Silva
2009-09-02T23:59:59.000Z
A gravity dual of a superconductor at finite temperature has been recently proposed. We present the vortex configuration of this model and study its properties. In particular, we calculate the free energy as a function of an external magnetic field, the magnetization and the superconducting density. We also find the two critical magnetic fields that define the region in which the vortex configurations are energetically favorable.
On the Observability of Pressure in a Pneumatic Servo Actuator
Barth, Eric J.
On the Observability of Pressure in a Pneumatic Servo Actuator Jianhui Wu, Michael Goldfarb pressure and, as such, are well suited to the use of nonlinear control methods re- quiring measurement of the full state, such as sliding mode con- trol. This paper investigates the possibility of eliminating
Zero-Energy Flows and Vortex Patterns in Quantum Mechanics
Tsunehiro Kobayashi
2003-02-20T23:59:59.000Z
We show that zero-energy flows appear in many particle systems as same as in single particle cases in 2-dimensions. Vortex patterns constructed from the zero-energy flows can be investigated in terms of the eigenstates in conjugate spaces of Gel'fand triplets. Stable patterns are written by the superposition of zero-energy eigenstates. On the other hand vortex creations and annihilations are described by the insertions of unstable eigenstates with complex-energy eigenvalues into the stable patterns. Some concrete examples are presented in the 2-dimensional parabolic potential barrier case. %, i.e., $-m \\gamma^2 (x^2+y^2)/2$. We point out three interesting properties of the zero-energy flows; (i) the absolute economy as for the energy consumption, (ii) the infinite variety of the vortex patterns, and (iii) the absolute stability of the vortex patterns .
Desingularization of periodic vortex sheet roll-up
Krasny, R.
1986-08-01T23:59:59.000Z
The equations governing periodic vortex sheet roll-up from analytic initial data are desingularized. Linear stability analysis shows that this diminishes the vortex sheet model's short wavelength instability, yielding a numerically more tractable set of equations. Computational evidence is presented which indicates that this approximation converges, beyond the critical time of singularity formation in the vortex sheet, if the mesh is refined and the smoothing parameter is reduced in the proper order. The results suggest that the vortex sheet rolls up into a double branched spiral past the critical time. It is demonstrated that either higher machine precision or a spectra filter can be used to maintain computational accuracy as the smoothing parameter is decreased. Some conjectures on the model's long time asymptotic state are given.
Ruben Minasian; Alessandro Tomasiello
2002-05-07T23:59:59.000Z
We explore the effects of non-abelian dynamics of D-branes on their stability and introduce Hitchin-like modifications to previously-known stability conditions. The relation to brane-antibrane systems is used in order to rewrite the equations in terms of superconnections and arrive at deformed vortex equations.
Minasian, R; Minasian, Ruben; Tomasiello, Alessandro
2001-01-01T23:59:59.000Z
We explore the effects of non-abelian dynamics of D-branes on their stability and introduce Hitchin-like modifications to previously-known stability conditions. The relation to brane-antibrane systems is used in order to rewrite the equations in terms of superconnections and arrive at deformed vortex equations.
Feasibility of a vortex transistor
Nevirkovets, I.P.; Rudenko, E.M.
1985-08-01T23:59:59.000Z
An experimental test is reported of the feasibility of developing a vortex transistor using tunnel junctions made from tin. (AIP)
Pneumatic brake control for precision stopping of heavy-duty vehicles
Bu, Fanping; Tan, Han-Shue
2007-01-01T23:59:59.000Z
desirable that the automatic brake control system uses thesystems,” IEEE Transactions on Automatic Control, vol. 41,enables automatic control of the pneumatic brake system and
Vortex-Based Aero- and Hydrodynamic Estimation
Hemati, Maziar Sam
2013-01-01T23:59:59.000Z
2001. [Kra91] R. Krasny. “Vortex Sheet Computations: Roll-NK94] M. Nitsche and R. Krasny. “A Numerical Study of Vortex
Design of a Free Piston Pneumatic Compressor as a Mobile Robot Power Supply
Barth, Eric J.
Design of a Free Piston Pneumatic Compressor as a Mobile Robot Power Supply Jose A. Riofrio.j.barth@vanderbilt.edu Abstract The design of a free piston compressor (FPC) intended as a pneumatic power supply is achieved by matching the dynamic load of the compressor to the ideal adiabatic expansion of the hot gas
Modeling the pneumatic relay valve of an s-cam air brake
Vilayannur Natarajan, Shankar
2005-08-29T23:59:59.000Z
by the driver, when there are no faults or defects in the brake system. This thesis is aimed at modeling and experimentally corroborating a subsystem of an air brake system, namely the pneumatic relay valve. The pneumatic relay valve takes a input signal from...
Terasaki, Mark
bone pneumatization in adults using cone beam computed tomography (CBCT) scans. Study Design. A total Oral Pathol Oral Radiol 2014;117:376-384) The advances in cone beam computed tomography (CBCT) overClassification and volumetric analysis of temporal bone pneumatization using cone beam computed
VORTEX BREAKDOWN INCIPIENCE: THEORETICAL CONSIDERATIONS
Erlebacher, Gordon
dimensional boundary layer (Hall 2;3 , Mager 4 ); (ii) vortex breakdown is a consequence of hydrodynamic instabilityVORTEX BREAKDOWN INCIPIENCE: THEORETICAL CONSIDERATIONS S. A. Berger Department of Mechanical in Science and Engineering NASA Langley Research Center Hampton, VA 236810001 ABSTRACT The sensitivity
Variable residence time vortex combustor
Melconian, Jerry O. (76 Beaver Rd., Reading, MA 01867)
1987-01-01T23:59:59.000Z
A variable residence time vortex combustor including a primary combustion chamber for containing a combustion vortex, and a plurality of louvres peripherally disposed about the primary combustion chamber and longitudinally distributed along its primary axis. The louvres are inclined to impel air about the primary combustion chamber to cool its interior surfaces and to impel air inwardly to assist in driving the combustion vortex in a first rotational direction and to feed combustion in the primary combustion chamber. The vortex combustor also includes a second combustion chamber having a secondary zone and a narrowed waist region in the primary combustion chamber interconnecting the output of the primary combustion chamber with the secondary zone for passing only lower density particles and trapping higher density particles in the combustion vortex in the primary combustion chamber for substantial combustion.
Vortex topology and the continuum limit of lattice gauge theories
G. Burgio
2007-10-02T23:59:59.000Z
We study the stability of Z_2 topological vortex excitations in d+1 dimensional SU(2) Yang-Mills theory on the lattice at T=0. This is found to depend on d and on the coupling considered. We discuss the connection with lattice artifacts causing bulk transitions in the beta_A-beta_F plane and draw some conclusions regarding the continuum limit of the theory.
PneUI: Pneumatically Actuated Soft Composite Materials for Shape Changing Interfaces
Yao, Lining
This paper presents PneUI, an enabling technology to build shape-changing interfaces through pneumatically-actuated soft composite materials. The composite materials integrate the capabilities of both input sensing and ...
CFD-DEM modelling of two-phase pneumatic conveying with experimental validation.
Ebrahimi, Mohammadreza
2014-11-27T23:59:59.000Z
A wide range of industrial processes involve multiphase granular flows. These include catalytic reactions in fluidized beds, the pneumatic conveying of raw materials and gas-particle separators. Due to the complex nature ...
Soft pneumatic artificial muscles with low threshold pressures for a cardiac compression device
Obiajulu, Steven (Steven C.)
2013-01-01T23:59:59.000Z
In this paper, I present the design, fabrication and characterization of fully soft pneumatic artificial muscles (PAMs) with low threshold pressures that are intended for direct cardiac compression (DCC). McKibben type ...
An investigation of pneumatic control on immiscible contaminant migration in confined aquifers
Watts, John David
1991-01-01T23:59:59.000Z
AN INVESTIGATION OF PNEUMATIC CONTROL ON IMMISCIBLE CONTAMINANT MIGRATION IN CONFINED AQUIFERS A Thesis by JOHN DAVID WATTS Submitted to the Office of Graduate Studies of Texas AkM University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE May 1991 Major Subject: Civil Engineering AN INVESTIGATION OF PNEUMATIC CONTROL ON IMMISCIBLE CONTAMINANT MIGRATION IN CONFINED AQUIFERS A Thesis by JOHN DAVID %VATTS Approved as to style and content by: W e . mes...
The determination of design data for the pneumatic conveying of sorghum seed
Person, Nat K
1959-01-01T23:59:59.000Z
of grain, more efficient and economical mechanical con- veying equipment is needed. Since the pneumatic conveyor has several advantages over other conveyors it is being used to psrt- iallv s:eet this need. A few of these advantages are as follows: 1.... The pneumatic conveyor is completely self-cleaning which eliminates the labor and the time ordinarily required to hand clean conveying equipment. In other types of conveyors this cleaning operation is necess- ary between each crop or variety. In instances...
Gravity waves from vortex dipoles and jets
Wang, Shuguang
2009-05-15T23:59:59.000Z
The dissertation first investigates gravity wave generation and propagation from jets within idealized vortex dipoles using a nonhydrostatic mesoscale model. Several initially balanced and localized jets induced by vortex dipoles are examined here...
Repeating pneumatic pipe-gun for plasma fueling
Viniar, I. [State Technical University, Saint Petersburg 195251 (Russia)] [State Technical University, Saint Petersburg 195251 (Russia); Sudo, S. [National Institute for Fusion Science, Nagoya 464-01 (Japan)] [National Institute for Fusion Science, Nagoya 464-01 (Japan)
1997-03-01T23:59:59.000Z
A pellet injector of the repeating pneumatic pipe-gun type has been designed for plasma fueling applications. Its use reduces the time for pellet formation by an {ital in situ} technique from 2 to 3 min to 2{endash}10 s. The basic idea of the proposed approach to pellet formation is to melt prefrozen solid fuel and to admit it through a porous unit into a barrel for refreezing. The injector provides for a continuous injection of an unlimited number of pellets. Over 250 hydrogen and deuterium pellets of 3 mm diameter and 3{endash}10 mm in length were accelerated to 1.2 km/s at a rate of 1 pellet per 10{endash}34 s by manually controlled injector operation. An automatically controlled multishot pellet injector ({gt}10 barrels) is capable of providing a continuous and reliable fueling of large fusion devices such as the large helical device and the International Thermonuclear Experimental Reactor (ITER). {copyright} {ital 1997 American Institute of Physics.}
Energy Spectrum of Vortex Tangle
Tsunehiko Araki; Makoto Tsubota; Sergey K. Nemirovskii
2001-06-29T23:59:59.000Z
The energy spectrum of superfluid turbulence in the absence of the normal fluid is studied numerically. In order to discuss the statistical properties, we calculated the energy spectra of the 3D velocity field induced by dilute and dense vortex tangles respectively, whose dynamics is calculated by the Biot-Savart law. In the case of a dense tangle, the slope of the energy spectrum is changed at $k=2\\pi/l$, where $l$ is the intervortex spacing. For $k>2\\pi/l$, the energy spectrum has $k^{-1}$ behavior in the same manner as the dilute vortex tangle, while otherwise the slope of the energy spectrum deviates from $k^{-1}$ behavior. We compare the behavior for $k<2\\pi/l$ with the Kolmogorov law.
Divergence of optical vortex beams
Reddy, Salla Gangi; Prabhakar, Shashi; Anwar, Ali; Banerji, J; Singh, R P
2015-01-01T23:59:59.000Z
We show, both theoretically and experimentally, that the propagation of optical vortices in free space can be analysed by using the width ($w(z)$) of the host Gaussian beam and the inner and outer radii of the vortex beam at the source plane ($z=0$) as defined in \\textit{Optics Letters \\textbf{39,} 4364-4367 (2014)}. We also studied the divergence of vortex beams, considered as the rate of change of inner or outer radius with the propagation distance, and found that it varies with the order in the same way as that of the inner and outer radii at zero propagation distance. These results may be useful in designing optical fibers for orbital angular momentum modes that play a crucial role in quantum communication.
Camesano, Terri
@wpi.edu ABSTRACT This paper presents the design of a magnetic resonance imaging (MRI) compatible pneumatic actuator@wpi.edu Gregory S. Fischer Mechanical Engineering Worcester Polytechnic Institute Worcester, MA 01609 gfischer provides high-fidelity soft tissue contrast and high spatial resolution. However, the high- field magnetic
A Soft Wearable Robotic Device for Active Knee Motions using Flat Pneumatic Artificial Muscles
Park, Yong-Lae
elastomer muscles were employed for assisted knee extension and flexion. The robotic device was testedA Soft Wearable Robotic Device for Active Knee Motions using Flat Pneumatic Artificial Muscles Yong present the design of a soft wearable robotic device composed of elastomeric artificial muscle actuators
OPTICAL DESIGN OF A NOVEL 2-STAGE SOLAR TROUGH CONCENTRATOR BASED ON PNEUMATIC POLYMERIC
-length 7.9 m-width sun-tracking prototype system. Theoretical maximum solar concentration ratio is 151 sunsOPTICAL DESIGN OF A NOVEL 2-STAGE SOLAR TROUGH CONCENTRATOR BASED ON PNEUMATIC POLYMERIC STRUCTURES Croce 1, 6710 Biasca, Switzerland 3 Solar Technology Laboratory, Paul Scherrer Institute, 5232 Villigen
The Role of Pressure Sensors in the Servo Control of Pneumatic Actuators
Barth, Eric J.
The Role of Pressure Sensors in the Servo Control of Pneumatic Actuators Jianhui Wu, Michael suited to the use of nonlinear control methods requiring measurement of the full state, such as sliding mode control. The requirement of pressure measurement, however, is particularly burdensome, due
On the Observability of Pressure in a Pneumatic Servo Actuator Michael Goldfarb
, such as sliding mode control. This paper investigates the possibility of eliminating the pressure measurementOn the Observability of Pressure in a Pneumatic Servo Actuator Jianhui Wu Michael Goldfarb Eric actuators are characterized by highly nonlinear dynamics from spool valve command to cylinder pressure
15-17 2546 Design and Construction of Rubber Pneumatic Artificial Muscles
Laksanacharoen, Sathaporn
17 15-17 2546 Design and Construction of Rubber Pneumatic Artificial Muscles 1 2 1 1518 Abstract The purpose of this research work is to design and construct the rubber artificial muscles and lateral displacement of the rubber artificial muscle. This research work is divided into two sections
Modeling the pneumatic subsystem of a S-cam air brake system
Coimbatore Subramanian, Shankar
2004-09-30T23:59:59.000Z
The air brake system is one of the critical components in ensuring the safe operation of any commercial vehicle. This work is directed towards the development of a fault-free model of the pneumatic subsystem of the air brake system. This model can...
Coulomb and viscous friction fault detection with application to a pneumatic actuator
Dunbar, William
Coulomb and viscous friction fault detection with application to a pneumatic actuator W.B. Dunbar of friction (fault) presented in this paper could facilitate the compensation of dry friction in high precision position- ing mechanisms. Moreover, a fault detection technique for monitoring dry friction would
Model-based Trajectory Control of Robots with Pneumatic Actuator Dynamics
Tedrake, Russ
movements despite being equipped with actuators (human muscles) that have band- width limitations similar. Motion planning has been successfully applied to a number of dynamic legged robots [13Model-based Trajectory Control of Robots with Pneumatic Actuator Dynamics Ryuma Niiyama Abstract
Computing Vortex Sheet Motion Robert Krasny
Krasny, Robert
Computing Vortex Sheet Motion Robert Krasny Department of Mathematics, University of Michigan, Ann;1574 Robert Krasny with respect to the time variable and obtained results consistent with Moore
Superconducting vortex pinning with artificially prepared nanostructures
Rosen, Yaniv Jacob
K. Schuller, “Enhanced superconducting vortex pinning withat T/Tc = 0.99 of a superconducting Nb thin film on aof the triangles. The superconducting critical temperature
Punkkinen, Henna, E-mail: henna.punkkinen@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, P.O. Box 1000, FI-02044 VTT (Finland); Merta, Elina, E-mail: elina.merta@vtt.fi [VTT Technical Research Centre of Finland, Biologinkuja 7, P.O. Box 1000, FI-02044 VTT (Finland); Teerioja, Nea, E-mail: nea.teerioja@helsinki.fi [University of Helsinki, Department of Economics and Management, Latokartanonkaari 9, P.O. Box 27, FI-00014 HY (Finland); Moliis, Katja, E-mail: katja.moliis@helsinki.fi [University of Helsinki, Department of Economics and Management, Latokartanonkaari 9, P.O. Box 27, FI-00014 HY (Finland); Kuvaja, Eveliina, E-mail: eveliina.kuvaja@helsinki.fi [University of Helsinki, Department of Economics and Management, Latokartanonkaari 9, P.O. Box 27, FI-00014 HY (Finland)
2012-10-15T23:59:59.000Z
Highlights: Black-Right-Pointing-Pointer We compare the environmental sustainability of two MSW collection systems. Black-Right-Pointing-Pointer We evaluate pneumatic and door-to-door collection systems. Black-Right-Pointing-Pointer The greenhouse gas emissions of pneumatic collection are around three times higher. Black-Right-Pointing-Pointer System components are decisive but assumptions on electricity use are also important. Black-Right-Pointing-Pointer Pneumatic collection could provide other benefits over door-to-door system. - Abstract: Waste collection is one of the life cycle phases that influence the environmental sustainability of waste management. Pneumatic waste collection systems represent a new way of arranging waste collection in densely populated urban areas. However, limited information is available on the environmental impacts of this system. In this study, we compare the environmental sustainability of conventional door-to-door waste collection with its hypothetical pneumatic alternative. Furthermore, we analyse whether the size of the hypothetical pneumatic system, or the number of waste fractions included, have an impact on the results. Environmental loads are calculated for a hypothetical pneumatic waste collection system modelled on an existing dense urban area in Helsinki, Finland, and the results are compared to those of the prevailing, container-based, door-to-door waste collection system. The evaluation method used is the life-cycle inventory (LCI). In this study, we report the atmospheric emissions of greenhouse gases (GHG), SO{sub 2} and NO{sub x}. The results indicate that replacing the prevailing system with stationary pneumatic waste collection in an existing urban infrastructure would increase total air emissions. Locally, in the waste collection area, emissions would nonetheless diminish, as collection traffic decreases. While the electricity consumption of the hypothetical pneumatic system and the origin of electricity have a significant bearing on the results, emissions due to manufacturing the system's components prove decisive.
aircraft vortex spacing: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
calculations and find that nontopological vortex solutions exist as well as Q-ball type solutions, but topological vortex solutions are not admitted. Inyong Cho; Youngone...
Vortex Hydro Energy Develops Transformational Technology to Harness...
Vortex Hydro Energy Develops Transformational Technology to Harness Energy from Water Currents Vortex Hydro Energy Develops Transformational Technology to Harness Energy from Water...
Light propagation around a relativistic vortex flow of dielectric medium
B. Linet
2000-11-06T23:59:59.000Z
We determine the path of the light around a dielectric vortex described by the relativistic vortex flow of a perfect fluid.
advanced vortex element: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
method with mesh adaptivity for computing vortex states in fastrotating BoseEinstein condensates Computer Technologies and Information Sciences Websites Summary: ) vortices, vortex...
accelerated vortex ring: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
rings and systems for controlled studies of vortex interactions in Bose-Einstein condensates HEP - Theory (arXiv) Summary: We study controlled methods of preparing vortex...
Ultra-Low NOx Advanced Vortex Combustor
Edmonds, R.G. (Ramgen Power Systems, Inc., Bellevue, WA); Steele, R.C. (Ramgen Power Systems, Inc., Bellevue, WA); Williams, J.T. (Ramgen Power Systems, Inc., Bellevue, WA); Straub, D.L.; Casleton, K.H.; Bining, Avtar (California Energy Commission, Sacramento, CA)
2006-05-01T23:59:59.000Z
An ultra lean-premixed Advanced Vortex Combustor (AVC) has been developed and tested. The natural gas fueled AVC was tested at the U.S. Department of Energy’s National Energy Technology Laboratory (USDOE NETL) test facility in Morgantown (WV). All testing was performed at elevated pressures and inlet temperatures and at lean fuel-air ratios representative of industrial gas turbines. The improved AVC design exhibited simultaneous NOx/CO/UHC emissions of 4/4/0 ppmv (all emissions are at 15% O2 dry). The design also achieved less than 3 ppmv NOx with combustion efficiencies in excess of 99.5%. The design demonstrated tremendous acoustic dynamic stability over a wide range of operating conditions which potentially makes this approach significantly more attractive than other lean premixed combustion approaches. In addition, a pressure drop of 1.75% was measured which is significantly lower than conventional gas turbine combustors. Potentially, this lower pressure drop characteristic of the AVC concept translates into overall gas turbine cycle efficiency improvements of up to one full percentage point. The relatively high velocities and low pressure drops achievable with this technology make the AVC approach an attractive alternative for syngas fuel applications.
ULTRA-LOW NOX ADVANCED VORTEX COMBUSTOR
Ryan G. Edmonds; Robert C. Steele; Joseph T. Williams; Douglas L. Straub; Kent H. Casleton; Avtar Bining
2006-05-01T23:59:59.000Z
An ultra lean-premixed Advanced Vortex Combustor (AVC) has been developed and tested. The natural gas fueled AVC was tested at the U.S. Department of Energy’s National Energy Technology Laboratory (USDOE NETL) test facility in Morgantown (WV). All testing was performed at elevated pressures and inlet temperatures and at lean fuel-air ratios representative of industrial gas turbines. The improved AVC design exhibited simultaneous NOx/CO/UHC emissions of 4/4/0 ppmv (all emissions are at 15% O2 dry). The design also achieved less than 3 ppmv NOx with combustion efficiencies in excess of 99.5%. The design demonstrated tremendous acoustic dynamic stability over a wide range of operating conditions which potentially makes this approach significantly more attractive than other lean premixed combustion approaches. In addition, a pressure drop of 1.75% was measured which is significantly lower than conventional gas turbine combustors. Potentially, this lower pressure drop characteristic of the AVC concept translates into overall gas turbine cycle efficiency improvements of up to one full percentage point. The relatively high velocities and low pressure drops achievable with this technology make the AVC approach an attractive alternative for syngas fuel applications.
Vortex dynamics in 4 Banavara N. Shashikanth
Shashikanth, Banavara N.
Vortex dynamics in 4 Banavara N. Shashikanth Citation: J. Math. Phys. 53, 013103 (2012); doi: 10 OF MATHEMATICAL PHYSICS 53, 013103 (2012) Vortex dynamics in R4 Banavara N. Shashikantha) Mechanical and Aerospace dynamics of Euler's equations for a constant density fluid flow in R4 is studied. Most of the paper focuses
An investigation of the vortex method
Pryor, D.W. Jr.
1994-05-01T23:59:59.000Z
The vortex method is a numerical scheme for solving the vorticity transport equation. Chorin introduced modern vortex methods. The vortex method is a Lagrangian, grid free method which has less intrinsic diffusion than many grid schemes. It is adaptive in the sense that elements are needed only where the vorticity is non-zero. Our description of vortex methods begins with the point vortex method of Rosenhead for two dimensional inviscid flow, and builds upon it to eventually cover the case of three dimensional slightly viscous flow with boundaries. This section gives an introduction to the fundamentals of the vortex method. This is done in order to give a basic impression of the previous work and its line of development, as well as develop some notation and concepts which will be used later. The purpose here is not to give a full review of vortex methods or the contributions made by all the researchers in the field. Please refer to the excellent review papers in Sethian and Gustafson, chapters 1 Sethian, 2 Hald, 3 Sethian, 8 Chorin provide a solid introduction to vortex methods, including convergence theory, application in two dimensions and connection to statistical mechanics and polymers. Much of the information in this review is taken from those chapters, Chorin and Marsden and Batchelor, the chapters are also useful for their extensive bibliographies.
Vortex rings impinging on permeable boundaries
Mujal-Colilles, Anna; Dalziel, Stuart B.; Bateman, Allen
2015-01-17T23:59:59.000Z
, and the existence of a rebound of the core parallel to the formation of a secondary 47 vortex with opposite sign [14]. 48 More recently, attention has turned to the possibility of resuspension due to a vortex ring 49 impacting a bed of particles (e.g. [1], [15...
Ergoregion instability: The hydrodynamic vortex
Leandro A. Oliveira; Vitor Cardoso; Luís C. B. Crispino
2014-05-16T23:59:59.000Z
Four-dimensional, asymptotically flat spacetimes with an ergoregion but no horizon have been shown to be linearly unstable against a superradiant-triggered mechanism. This result has wide implications in the search for astrophysically viable alternatives to black holes, but also in the understanding of black holes and Hawking evaporation. Here we investigate this instability in detail for a particular setup which can be realized in the laboratory: the {\\it hydrodynamic vortex}, an effective geometry for sound waves, with ergoregion and without an event horizon.
V. E. Shapiro
2011-09-22T23:59:59.000Z
This work formulates and gives grounds for general principles and theorems that question the energy function doctrine and its quantum version as a genuine law of nature without borders of adequacy. The emphasis is on the domain where the energy of systems is conserved -- I argue that only in its tiny part the energy is in the kinetic, potential and thermal forms describable by a generalized thermodynamic potential, whereas otherwise the conserved energy constitutes a whole linked to vortex forces, and can be a factor of things like persistent currents and dark matter.
Vortex Energy | Open Energy Information
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative Fuels Data Center Home Page onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnualProperty Edit withTianlin BaxinUmweltVillageGraph Home Wzeng'sVortex Energy Jump to:
Liu, C.; Bruner, H. L.; Deng, S.; Brundidge, T.; Turner, W. D.; Claridge, D. E.
2004-01-01T23:59:59.000Z
, had some form of deteriorated controls, components, and operational function. For example, most of pneumatic controls were failed due to bad components, wrong settings, and disconnection before the Continuous CommissioningR (CCSM). This caused humid...
Book Review Delft Pneumatic Bipeds by Martijn Wisse and Richard Q. van der Linde, Springer Tracts in
Poulakakis, Ioannis
1 Book Review Delft Pneumatic Bipeds by Martijn Wisse and Richard Q. van der Linde, Springer Tracts and van der Linde constructed at Delft, The Netherlands, a series of five bipeds, starting with a Mc
Vortex pinning by inhomogeneities in type-II superconductors
Chapman, Jon
Vortex pinning by inhomogeneities in type-II superconductors S.J. Chapman #3;y G. Richardson zx of a curvilinear vortex in an inhomogeneous type-II superconducting material in the limit as the vortex core radius of the superconducting electrons acts as a pinning potential for the vortex, so that vortices will be attracted
The prevention of oil spreading on water by pneumatic bubble barrier
McClenan, Cecil Michael
1971-01-01T23:59:59.000Z
the channel center line. Flexible tubing connected the pitot tube to a 36 manometer which was located on an adjustable stand attached to the carriage. A carpenter's level and rule set the manometer slope at 1:5 to produce a more pro- nounced reading... patience and help in the preparation of this thesis. TABLE OF CONTENTS Section INTRODUCTION LITERATURE SURVEY Gravity Waves Page 5 5 Pneumatically Generated Surface Currents . . . 15 THEORETICAL CONSIDERATIONS 19 Dimensional Analysis . Control...
Sun, Xuefei; Kelly, Ryan T.; Danielson, William F.; Agrawal, Nitin; Tang, Keqi; Smith, Richard D.
2011-04-26T23:59:59.000Z
A novel hydrodynamic injector that is directly controlled by a pneumatic valve has been developed for reproducible microchip capillary electrophoresis (CE) separations. The poly(dimethylsiloxane) (PDMS) devices used for evaluation comprise a separation channel, a side channel for sample introduction, and a pneumatic valve aligned at the intersection of the channels. A low pressure (? 3 psi) applied to the sample reservoir is sufficient to drive sample into the separation channel. The rapidly actuated pneumatic valve enables injection of discrete sample plugs as small as ~100 pL for CE separation. The injection volume can be easily controlled by adjusting the intersection geometry, the solution back pressure and the valve actuation time. Sample injection could be reliably operated at different frequencies (< 0.1 Hz to >2 Hz) with good reproducibility (peak height relative standard deviation ? 3.6%) and no sampling biases associated with the conventional electrokinetic injections. The separation channel was dynamically coated with a cationic polymer, and FITC-labeled amino acids were employed to evaluate the CE separation. Highly efficient (? 7.0 × 103 theoretical plates for the ~2.4 cm long channel) and reproducible CE separations were obtained. The demonstrated method has numerous advantages compared with the conventional techniques, including repeatable and unbiased injections, no sample waste, high duty cycle, controllable injected sample volume, and fewer electrodes with no need for voltage switching. The prospects of implementing this injection method for coupling multidimensional separations, for multiplexing CE separations and for sample-limited bioanalyses are discussed.
Spatiotemporal characterization of ultrashort optical vortex pulses
Miranda, Miguel; Rudawski, Piotr; Guo, Chen; Harth, Anne; L'Huillier, Anne; Arnold, Cord L
2015-01-01T23:59:59.000Z
Generation of few-cycle optical vortex pulses is challenging due to the large spectral bandwidths, as most vortex generation techniques are designed for monochromatic light. In this work, we use a spiral phase plate to generate few-cycle optical vortices from an ultrafast titanium:sapphire oscillator, and characterize them in the spatiotemporal domain using a recently introduced technique based on spatially resolved Fourier transform spectrometry. The performance of this simple approach to the generation of optical vortices is analyzed from a wavelength dependent perspective, as well as in the spatiotemporal domain, allowing us to completely characterize ultrashort vortex pulses in space, frequency, and time.
Kleckner, Dustin; Irvine, William T M
2013-01-01T23:59:59.000Z
The idea that the knottedness (hydrodynamic Helicity) of a fluid flow is conserved has a long history in fluid mechanics. The quintessential example of a knotted flow is a knotted vortex filament, however, owing to experimental difficulties, it has not been possible until recently to directly generate knotted vortices in real fluids. Using 3D printed hydrofoils and high-speed laser scanning tomography, we generate vortex knots and links and measure their subsequent evolution. In both cases, we find that the vortices deform and stretch until a series of vortex reconnections occurs, eventually resulting several disjoint vortex rings. This article accompanies a fluid dynamics video entered into the Gallery of Fluid Motion at the 66th Annual Meeting of the APS Division of Fluid Dynamics.
Josephson vortex lattice in layered superconductors
Koshelev, A. E., E-mail: koshelev@anl.gov [Argonne National Laboratory, Materials Science Division (United States); Dodgson, M. J. W. [Cavendish Laboratory, Theory of Condensed Matter Group (United Kingdom)] [Cavendish Laboratory, Theory of Condensed Matter Group (United Kingdom)
2013-09-15T23:59:59.000Z
Many superconducting materials are composed of weakly coupled conducting layers. Such a layered structure has a very strong influence on the properties of vortex matter in a magnetic field. This review focuses on the properties of the Josephson vortex lattice generated by the magnetic field applied in the direction of the layers. The theoretical description is based on the Lawrence-Doniach model in the London limit, which takes only the phase degree of freedom of the superconducting order parameter into account. In spite of its simplicity, this model leads to an amazingly rich set of phenomena. We review in detail the structure of an isolated vortex line and various properties of the vortex lattice, in both dilute and dense limits. In particular, we extensively discuss the influence of the layered structure and thermal fluctuations on the selection of lattice configurations at different magnetic fields.
The multiple vortex nature of tropical cyclogenesis
Sippel, Jason Allen
2005-02-17T23:59:59.000Z
cells and vortices are the respective source of PV production and building blocks for the meso-?-scale vortices. Finally, this thesis discusses issues related to the multiple vortex nature of tropical cyclone formation. For instance, the tracking...
Direct Imaging of Antiferromagnetic Vortex States
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
H.W. Zhao, J. Bokor, and Z.Q. Qiu, "Direct observation of imprinted antiferromagnetic vortex states in CoOFeAg(001) discs," Nat. Phys. 7, 303 (2011). ALS Science Highlight 235...
Direct Imaging of Antiferromagnetic Vortex States
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
and Z.Q. Qiu, "Direct observation of imprinted antiferromagnetic vortex states in CoOFeAg(001) discs," Nat. Phys. 7, 303 (2011). ALS Science Highlight 235 ALSNews Vol. 324...
Phases of Atom-Molecule Vortex Matter
Woo, S. J.; Bigelow, N. P. [Department of Physics and Astronomy, University of Rochester, Rochester, New York (United States); Park, Q-Han [Department of Physics, Korea University, Seoul (Korea, Republic of)
2008-03-28T23:59:59.000Z
We study ground state vortex configurations in a rotating atom-molecule Bose-Einstein condensate. It is found that the coherent coupling between the atomic and molecular condensates can render a pairing of atomic and molecular vortices into a composite structure that resembles a carbon dioxide molecule. Structural phase transitions of vortex lattices are also explored through different physical parameters including the rotational frequency of the system.
Reconnection of vortex filaments and Kolmogorov spectrum
Sergey K. Nemirovskii
2014-04-19T23:59:59.000Z
The energy spectrum of the 3D velocity field, induced by collapsing vortex filaments is studied. One of the aims of this work is to clarify the appearance of the Kolmogorov type energy spectrum $E(k)\\varpropto k^{-5/3}$, observed in many numerical works on discrete vortex tubes (quantized vortex filaments in quantum fluids). Usually, explaining classical turbulent properties of quantum turbulence, the model of vortex bundles, is used. This model is necessary to mimic the vortex stretching, which is responsible for the energy transfer in classical turbulence. In our consideration we do not appeal to the possible "bundle arrangement" but explore alternative idea that the turbulent spectra appear from singular solution, which describe the collapsing line at moments of reconnection. One more aim is related to an important and intensively discussed topic - a role of hydrodynamic collapse in the formation of turbulent spectra. We demonstrated that the specific vortex filament configuration generated the spectrum $E(k)$ close to the Kolmogorov dependence and discussed the reason for this as well as the reason for deviation. We also discuss the obtained results from point of view of the both classical and quantum turbulence.
Vortex Hydro Energy (TRL 5 6 System) - Advanced Integration of...
Broader source: Energy.gov (indexed) [DOE]
Vortex Hydro Energy (TRL 5 6 System) - Advanced Integration of Power Take-Off in VIVACE Vortex Hydro Energy (TRL 5 6 System) - Advanced Integration of Power Take-Off in VIVACE...
Fractal powers in Serrin's swirling vortex solutions
Pavel B?lík; Douglas P. Dokken; Kurt Scholz; Mikhail M. Shvartsman
2014-04-28T23:59:59.000Z
We consider a modification of the fluid flow model for a tornado-like swirling vortex developed by J. Serrin, where velocity decreases as the reciprocal of the distance from the vortex axis. Recent studies, based on radar data of selected severe weather events, indicate that the angular momentum in a tornado may not be constant with the radius, and thus suggest a different scaling of the velocity/radial distance dependence. Motivated by this suggestion, we consider Serrin's approach with the assumption that the velocity decreases as the reciprocal of the distance from the vortex axis to the power $b$ with a general $b>0$. This leads to a boundary-value problem for a system of nonlinear differential equations. We analyze this problem for particular cases, both with nonzero and zero viscosity, discuss the question of existence of solutions, and use numerical techniques to describe those solutions that we cannot obtain analytically.
Removing the concavity of the thick center vortex potentials by fluctuating the vortex profile
Sedigheh Deldar; Shahnoosh Rafibakhsh
2010-03-14T23:59:59.000Z
The thick center vortex model reproduces important aspects of the potentials between static quark sources as seen in lattice Yang-Mills calculations: Both the intermediate distance behavior, governed by Casimir scaling, as well as the long distance behavior, governed by N-ality, are obtained. However, when a fixed vortex profile is used, these two distance regimes do not connect naturally to each other. The transition in general violates concavity constraints on the potential, especially for higher representations of the gauge group. We demonstrate how this issue can be alleviated when the vortex profile is allowed to fluctuate within this simple model.
Water gate array for current flow or tidal movement pneumatic harnessing system
Gorlov, Alexander M. (Brookline, MA)
1991-01-01T23:59:59.000Z
The invention, which provides a system for harnessing power from current flow or tidal movement in a body of water, comprises first and second hydro-pneumatic chambers each having ingress and egress below the water surface near the river or ocean floor and water gates operative to open or seal the ports to the passage of water. In an exemplary embodiment, the gates are sychronized by shafts so that the ingress ports of each chamber are connected to the egress ports of each other chamber. Thus, one set of gates is closed, while the other is open, thereby allowing water to flow into one chamber and build air pressure therein and allowing water to flow out of the other chamber and create a partial vacuum therein. A pipe connects the chambers, and an air turbine harnesses the air movement within the pipe. When water levels are equilibrated, the open set of gates is closed by a counterweight, and the other set is allowed to open by natural force of the water differential. The water gates may be comprised of a plurality of louvers which are ganged for simultaneous opening and closing. The system is designed to operate with air turbines or other pneumatic devices. Its design minimizes construction cost and environmental impact, yet provides a clean renewable energy source.
Acoustics of finite-aperture vortex beams
Mitri, F G
2014-01-01T23:59:59.000Z
A method based on the Rayleigh-Sommerfeld surface integral is provided, which makes it feasible to rigorously model, evaluate and compute the acoustic scattering and other mechanical effects of finite-aperture vortex beams such as the acoustic radiation force and torque on a viscoelastic sphere in various applications in acoustic tweezers and microfluidics, particle entrapment, manipulation and rotation. Partial-wave series expansions are derived for the incident field of acoustic spiraling (vortex) beams, comprising high-order Bessel and Bessel-Gauss beams.
Invariants for Tendex and Vortex Fields
Kenneth A. Dennison; Thomas W. Baumgarte
2012-08-06T23:59:59.000Z
Tendex and vortex fields, defined by the eigenvectors and eigenvalues of the electric and magnetic parts of the Weyl curvature tensor, form the basis of a recently developed approach to visualizing spacetime curvature. In analogy to electric and magnetic fields, these fields are coordinate-dependent. However, in a further analogy, we can form invariants from the tendex and vortex fields that are invariant under coordinate transformations, just as certain combinations of the electric and magnetic fields are invariant under coordinate transformations. We derive these invariants, and provide a simple, analytical demonstration for non-spherically symmetric slices of a Schwarzschild spacetime.
Neutron Scattering Studies of Vortex Matter in Type-II Superconductors
Xinsheng Ling
2012-02-02T23:59:59.000Z
The proposed program is an experimental study of the fundamental properties of Abrikosov vortex matter in type-II superconductors. Most superconducting materials used in applications such as MRI are type II and their transport properties are determined by the interplay between random pinning, interaction and thermal fluctuation effects in the vortex state. Given the technological importance of these materials, a fundamental understanding of the vortex matter is necessary. The vortex lines in type-II superconductors also form a useful model system for fundamental studies of a number of important issues in condensed matter physics, such as the presence of a symmetry-breaking phase transition in the presence of random pinning. Recent advances in neutron scattering facilities such as the major upgrade of the NIST cold source and the Spallation Neutron Source are providing unprecedented opportunities in addressing some of the longstanding issues in vortex physics. The core component of the proposed program is to use small angle neutron scattering and Bitter decoration experiments to provide the most stringent test of the Bragg glass theory by measuring the structure factor in both the real and reciprocal spaces. The proposed experiments include a neutron reflectometry experiment to measure the precise Q-dependence of the structure factor of the vortex lattice in the Bragg glass state. A second set of SANS experiments will be on a shear-strained Nb single crystal for testing a recently proposed theory of the stability of Bragg glass. The objective is to artificially create a set of parallel grain boundaries into a Nb single crystal and use SANS to measure the vortex matter diffraction pattern as a function of the changing angle between the applied magnetic field to the grain boundaries. The intrinsic merits of the proposed work are a new fundamental understanding of type-II superconductors on which superconducting technology is based, and a firm understanding of phases and phase transitions in condensed matter systems with random pinning. The broader impact of the program includes the training of future generation of neutron scientists, and further development of neutron scattering and complementary techniques for studies of superconducting materials. The graduate and undergraduate students participating in this project will learn the state-of-the-art neutron scattering techniques, acquire a wide range of materials research experiences, and participate in the frontier research of superconductivity. This should best prepare the students for future careers in academia, industry, or government.
Claeys, Philippe
Evaluation of pneumatic nebulization and ns-laser ablation ICP-MS for bulk elemental analysis and 2 nebulization and ns-laser ablation ICP-MS for bulk elemental analysis and 2-dimensional element mapping of iron 20XX DOI: 10.1039/b000000x The capabilities and limitations of nanosecond laser ablation ICP mass
Barth, Eric J.
of pressure whose value is to be estimated. In the second method, sliding-mode pressure observer design-based control techniques such as sliding mode and adaptive control. These controllers require full state knowledge of the system, viz. pressure, position, and velocity. For measuring two of the states, pneumatic
Barth, Eric J.
presents the development of a robust observer based controller to eliminate costly pressure sensors the effectiveness of this pressure observer based controller. I. INTRODUCTION HE use of pneumatic systems for task robotic uses. Pandian et al. [1] presented a sliding mode controller for position control that showed good
Yao, Bin
rotation angle is normally not measured and controlled when these types of manipulator are used in practice controller for the pneumatic muscles driven redundant parallel manipulator. I. INTRODUCTION neumatic muscle and controlled to save cost when using these types of parallel manipulators in practice, leading to a DOF
Convergenceof Vortex Methods for Weak Solutionsto the
Liu, Jian-Guo
, Krasny applied such a method in his calculations of the evolution of vortex sheetseven past the time when numerical simulations;see Krasny, [16] and [17], and Baker and Shelley, [l]. It is thus important to analyze by Krasny (see [16] and [17]). Our analysis is closely related to that of [9], [lo], and [18], and based
Quenching Processes in Flame-Vortex Interactions
Zingale, Michael
for Astrophysical Thermonuclear Flashes 1 , Chicago, IL 60637 y Department of Astronomy and Astrophysics, University-vortex interactions in order to understand quenching of thermonuclear ames. The key question is|can a ther- monuclear. If a ame encounters a 1) The Center for Astrophysical Thermonuclear Flashes is supported by the Department
Bifurcation to vortex solutions in superconducting lms
Chapman, Jon
Bifurcation to vortex solutions in superconducting #12;lms T. Boeck #3; S.J. Chapman y Mathematical state to a superconducting state in a decreasing magnetic #12;eld is studied for a slab geometry of these behaviours will occur in practice. 1 Introduction If a superconducting body is placed in a suÃ?ciently strong
Integration of pneumatic fracturing and in situ vitrification in the soil subsurface
Luey, J.; Seiler, D.K. [Pacific Northwest Lab., Richland, WA (United States); Schuring, J.R.
1995-02-01T23:59:59.000Z
Pacific Northwest Laboratory is evaluating ways to increase the applicability of the in situ vitrification (ISV) process at hazardous and radioactive waste sites. One innovation is the placement of a conductive material that will facilitate initiating the ISV process at a target depth. A series of laboratory tests performed at the New Jersey Institute of Technology (NJIT) assessed the feasibility of pneumatic fracturing (PF) in the highly permeable soils of the Hanford Site. The NJIT tests included an analysis of Hanford soils, a series of PF injection tests, and a parametric analysis to determine how soil properties affect the PF process. Results suggest that the PF process can be applied to Hanford soils and that dry medium (e.g., conductive material such as graphite flake) can be injected into the fracture. This paper describes the laboratory testing performed at NJIT, its results, and the application of those results to plans for a field demonstration at Hanford.
Bose-Einstein Condensation in an electro-pneumatically transformed quadrupole-Ioffe magnetic trap
Sunil Kumar; Sumit Sarkar; Gunjan Verma; Chetan Vishwakarma; Md. Noaman; Umakant Rapol
2014-08-20T23:59:59.000Z
We report a novel approach for preparing a Bose-Einstein condensate (BEC) of $^{87}$Rb atoms using electro-pneumatically driven transfer of atoms into a Quadrupole-Ioffe magnetic trap (QUIC Trap). More than 5$\\times$$10^{8}$ atoms from a Magneto-optical trap are loaded into a spherical quadrupole trap and then these atoms are transferred into an Ioffe trap by moving the Ioffe coil towards the center of the quadrupole coil, thereby, changing the distance between quadrupole trap center and the Ioffe coil. The transfer efficiency is more than 80 \\%. This approach is different from a conventional approach of loading the atoms into a QUIC trap wherein the spherical quadrupole trap is transformed into a QUIC trap by changing the currents in the quadrupole and the Ioffe coils. The phase space density is then increased by forced rf evaporative cooling to achieve the Bose-Einstein condensation having more than $10^{5}$ atoms.
Barth, Eric J.
Motivation for Impedance Control of a Pneumatic Actuator Problem Industrial robots are good industrial robot actuators (hydraulic and motor/gearhead systems) are highly stiff system and are better
Strings, vortex rings, and modes of instability
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Gubser, Steven S.; Nayar, Revant; Parikh, Sarthak
2015-03-01T23:59:59.000Z
We treat string propagation and interaction in the presence of a background Neveu–Schwarz three-form field strength, suitable for describing vortex rings in a superfluid or low-viscosity normal fluid. A circular vortex ring exhibits instabilities which have been recognized for many years, but whose precise boundaries we determine for the first time analytically in the small core limit. Two circular vortices colliding head-on exhibit stronger instabilities which cause splitting into many small vortices at late times. We provide an approximate analytic treatment of these instabilities and show that the most unstable wavelength is parametrically larger than a dynamically generated length scalemore »which in many hydrodynamic systems is close to the cutoff. We also summarize how the string construction we discuss can be derived from the Gross–Pitaevskii Lagrangian, and also how it compares to the action for giant gravitons.« less
Deterministic Josephson Vortex Ratchet with a load
M. Knufinke; K. Ilin; M. Siegel; D. Koelle; R. Kleiner; E. Goldobin
2011-09-29T23:59:59.000Z
We investigate experimentally a deterministic underdamped Josephson vortex ratchet -- a fluxon-particle moving along a Josephson junction in an asymmetric periodic potential. By applying a sinusoidal driving current one can compel the vortex to move in a certain direction, producing average dc voltage across the junction. Being in such a rectification regime we also load the ratchet, i.e., apply an additional dc bias current I_dc (counterforce) which tilts the potential so that the fluxon climbs uphill due to the ratchet effect. The value of the bias current at which the fluxon stops climbing up defines the strength of the ratchet effect and is determined experimentally. This allows us to estimate the loading capability of the ratchet, the output power and efficiency. For the quasi-static regime we present a simple model which delivers simple analytic expressions for the above mentioned figures of merit.
Vortex state in a doped Mott insulator M. Franz and Z. Tesanovic
Tesanovic, Zlatko
predicts two types of singly quantized vortices: an insulating ``holon'' vortex in the underdoped and a metallic ``spinon'' vortex in the overdoped region of the phase diagram. We argue that the holon vortex
Multiple precision, multiple processor vortex sheet roll-up computation
Bailey, D.H. [NASA Ames Research Center, Moffett Field, CA (United States); Krasny, R. [Univ. of Michigan, Ann Arbor, MI (United States); Pelz, R. [Rutgers Univ., Piscataway, NJ (United States)
1993-12-31T23:59:59.000Z
A vortex sheet in incompressible flow is a surface across which the tangential fluid velocity has a jump discontinuity. A basic idea in fluid dynamics going back to Prandtl is that the vortex sheet can be obtained as the zero viscosity limit of a sequence of smooth solutions to the Navier-Stokes equations. Thus, the investigation of vortex sheet motion may yield insight into the structure of high Reynolds number flow.
Optical vortex interaction and generation via nonlinear wave mixing
Lenzini, F. [INLN, Universite de Nice-Sophia Antipolis, CNRS, 1361 route des Lucioles, FR-06560 Valbonne (France); Dipartimento di Fisica, Universita di Firenze, via Sansone 1, IT-50019 Sesto Fiorentino (Italy); Residori, S.; Bortolozzo, U. [INLN, Universite de Nice-Sophia Antipolis, CNRS, 1361 route des Lucioles, FR-06560 Valbonne (France); Arecchi, F. T. [Dipartimento di Fisica, Universita di Firenze, via Sansone 1, IT-50019 Sesto Fiorentino (Italy)
2011-12-15T23:59:59.000Z
Optical vortex beams are made to interact via degenerate two-wave mixing in a Kerr-like nonlinear medium. Vortex mixing is shown to occur inside the medium, leading to exchange of topological charge and cascaded generation of vortex beams. A mean-field model is developed and is shown to account for the selection rules of the topological charges observed after the wave-mixing process. Fractional charges are demonstrated to follow the same rules as for integer charges.
Laboratory Analysis of Vortex Dynamics For Shallow Tidal Inlets
Whilden, Kerri Ann
2010-10-12T23:59:59.000Z
of the secondary structures into the vortex system are shown as well as variations in characteristics such as trajectory, size, vorticity, and circulation for the vortices as they move downstream. iv To the loved ones who have encouraged me along the way. v.... : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 30 13 Non-Dimensional Vorticity at the Swirl Strength Peak for the Pri- mary Vortex Within the Vortex System Versus Non-Dimensional Horizontal Location of the Centroid. : : : : : : : : : : : : : : : : : : 31 14 Non-Dimensional Circulation...
Liquid Vortex Shielding for Fusion Energy Applications
Bardet, Philippe M. [University of California, Berkeley (United States); Supiot, Boris F. [University of California, Berkeley (United States); Peterson, Per F. [University of California, Berkeley (United States); Savas, Oemer [University of California, Berkeley (United States)
2005-05-15T23:59:59.000Z
Swirling liquid vortices can be used in fusion chambers to protect their first walls and critical elements from the harmful conditions resulting from fusion reactions. The beam tube structures in heavy ion fusion (HIF) must be shielded from high energy particles, such as neutrons, x-rays and vaporized coolant, that will cause damage. Here an annular wall jet, or vortex tube, is proposed for shielding and is generated by injecting liquid tangent to the inner surface of the tube both azimuthally and axially. Its effectiveness is closely related to the vortex tube flow properties. 3-D particle image velocimetry (PIV) is being conducted to precisely characterize its turbulent structure. The concept of annular vortex flow can be extended to a larger scale to serve as a liquid blanket for other inertial fusion and even magnetic fusion systems. For this purpose a periodic arrangement of injection and suction holes around the chamber circumference are used, generating the layer. Because it is important to match the index of refraction of the fluid with the tube material for optical measurement like PIV, a low viscosity mineral oil was identified and used that can also be employed to do scaled experiments of molten salts at high temperature.
active vortex generators: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
how an initial dusturbing cyclonic vortex is created by collision between two linear wind jets under certain conditions, which under favorable conditions, may mature into a...
Combs, S.K.; Foust, C.R.; Milora, S.L. (Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831 (United States))
1995-03-01T23:59:59.000Z
Repeating pneumatic pellet injectors developed at the Oak Ridge National Laboratory (ORNL) were used for plasma fueling experiments on the Tokamak Fusion Test Reactor (TFTR) and the Joint European Torus (JET). For plasma fueling on the DIII--D tokamak, a small-bore (1.8-mm) injector has been developed and tested in the laboratory at pellet rates of up to 10 Hz and speeds of [le]1 km/s (for pulse lengths of up to 15 s). This performance represents the smallest pellet size and highest repetition rate demonstrated with an ORNL repeating pneumatic pellet injector. The design has been incorporated in the three-barrel injector that was previously used on JET; the injection system, equipped with nominal pellet sizes of 1.8-, 2.7-, and 4.0-mm diameter, has been installed on DIII--D and will be used in future plasma fueling experiments.
Center Manifold Analysis of a PointVortex Model of Vortex Shedding with Control
Protas, Bartosz
of the point vortex FÂ¨oppl system with linear feedback control. The FÂ¨oppl system was used in an earlier system. Key words: point vortices, flow control, dynamical systems, wake flows PACS: 47.15.Hg, 47.27.Rc, 47.27.Vf 1 Introduction Integration of rigorous methods of Modern Control Theory with Computational
Center Vortex vs. Abelian models of the QCD vacuum
Höllwieser, Roman
2015-01-01T23:59:59.000Z
We present evidence that the center vortex model of confinement is more consistent with lattice results than other currently available models. In particular we show that Abelian field distributions predicted by monopole plasma, caloron gas or dual superconductor models cannot reproduce the area-law falloff of double winding Wilson loops in full $SU(2)$ and center vortex only gauge fields.
Vortex Lattice Modelling of Winglets on Wind Turbine Blades
Vortex Lattice Modelling of Winglets on Wind Turbine Blades Mads DÃ¸ssing RisÃ¸-R-1621(EN) RisÃ¸ Title: Vortex Lattice Modelling of Winglets on Wind Turbine Blades Departments: Wind Energy Department turbines can be increased by the use of winglets without increasing the swept area. This makes them
Geometrical statistics and vortex structures in helical and nonhelical turbulences
Li, Yi
, United Kingdom Received 4 August 2009; accepted 20 January 2010; published online 9 March 2010 explained in terms of the self-induced motions of local vortex structures, which tend to wind up the vortexÂ11,13Â15 the effects of helicity on energy cascade,16 the interaction between helicity and energy dissipation,17
Zaltash, A.
1987-01-01T23:59:59.000Z
Application of thermodynamic analogy to pneumatic transport in 0.0266 m and 0.0504 m systems held at various angles of inclination was investigated. Particles used in these systems included glass particles of 67 ..mu..m, 450 ..mu..m, and 900 ..mu..m weight mean diameter as well as iron ore of 400 ..mu..m weight mean diameter. An equation of state similar to the van der Waals has been suggested for these systems. Measurements in these experimental set-ups included pressure drops, particle velocities, and solids mass flow rates in both the upper and lower halves of the pipe. These measurements were used to describe the phase behavior of the systems studied. It was found that the van der Waals analog is capable of describing the phase behavior of these systems. A method has been proposed to estimate the parameters of the van der Waals analog equation. The incorporation of dimensionless pressure drop into the analysis has been attempted by the use of energy functions in thermodynamics. The effect of inclination angle, pipe diameter, and particle characteristics on basic flow parameters were studied. The ratio of solids flow in the top half to that of the bottom half of the pipe showed that the concentration gradient is influenced by particle characteristics, and by the pipe diameter and orientation. Glass test section was used in these systems for visual observations of the flow patterns. 53 refs., 176 figs., 52 tabs.
Electron vortex beams in a magnetic field and spin filter
Debashree Chowdhury; Banasri Basu; Pratul Bandyopadhyay
2015-02-25T23:59:59.000Z
We investigate the propagation of electron vortex beams in a magnetic field. It is pointed out that when electron vortex beams carrying orbital angular momentum propagate in a magnetic field, the Berry curvature associated with the scalar electron moving in a cyclic path around the vortex line is modified from that in free space. This alters the spin-orbit interaction, which affects the propagation of nonparaxial beams. The electron vortex beams with tilted vortex lead to spin Hall effect in free space. In presence of a magnetic field in time space we have spin filtering such that either positive or negative spin states emerge in spin Hall currents with clustering of spin $\\frac{1}{2}$ states.
Vortex and Droplet Engineering in Holographic Superconductors
Tameem Albash; Clifford V. Johnson
2009-08-22T23:59:59.000Z
We give a detailed account of the construction of non--trivial localized solutions in a 2+1 dimensional model of superconductors using a 3+1 dimensional gravitational dual theory of a black hole coupled to a scalar field. The solutions are found in the presence of a background magnetic field. We use numerical and analytic techniques to solve the full Maxwell--scalar equations of motion in the background geometry, finding condensate droplet solutions, and vortex solutions possessing a conserved winding number. These solutions and their properties, which we uncover, help shed light on key features of the (B,T) phase diagram.
Vortex lattice for a holographic superconductor
Kengo Maeda; Makoto Natsuume; Takashi Okamura
2009-12-17T23:59:59.000Z
We investigate the vortex lattice solution in a (2+1)-dimensional holographic model of superconductors constructed from a charged scalar condensate. The solution is obtained perturbatively near the second-order phase transition and is a holographic realization of the Abrikosov lattice. Below a critical value of magnetic field, the solution has a lower free energy than the normal state. Both the free energy density and the superconducting current are expressed by nonlocal functions, but they reduce to the expressions in the Ginzburg-Landau (GL) theory at long wavelength. As a result, a triangular lattice becomes the most favorable solution thermodynamically as in the GL theory of type II superconductors.
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Rohde, Axel
and 1000 diameters, alternate vortex shedding begins, and a von Karman vortex street develops in the wake of Vortex Instability in a 2-D Compressible Flow over a Cylinder Axel Rohde Department of Aerospace start and reveals the evolution of vortex instability. After the cylinder has traveled between 100
Non-Riemannian geometry of vortex acoustics
Garcia de Andrade, L.C. [Departamento de Fisica Teorica, Instituto de Fisica, Universidade Estadual do Rio de Janeiro, Rua Sao Francisco Xavier 524, Maracana, 20550, Rio de Janeiro, RJ (Brazil)
2004-09-15T23:59:59.000Z
The concept of acoustic torsion is introduced by making use of the scalar wave equation in Riemann-Cartan spacetime. Acoustic torsion extends the acoustic metric previously given by Unruh (PRL-1981). The wave equation describes irrotational perturbations in rotational nonrelativistic fluids. This physical motivation allows us to show that the acoustic line element can be conformally mapped to the line element of a stationary torsion loop in non-Riemannian gravity. Two examples of such sonic analogues are given. The first is the stationary torsion loop in teleparallel gravity. In the far from the vortex approximation, the Cartan torsion vector is shown to be proportional to the quantum vortex number of the superfluid. The torsion vector is also shown to be proportional to the superfluid vorticity in the presence of vortices. The formation of superfluid vortices is shown not to be favored by torsion loops in Riemann-Cartan spacetime, as long as this model is concerned. It is suggested that the teleparallel model may help to find a model for superfluid neutron stars vortices based on non-Riemannian gravity.
Ferroelectric nanostructure having switchable multi-stable vortex states
Naumov, Ivan I. (Fayetteville, AR); Bellaiche, Laurent M. (Fayetteville, AR); Prosandeev, Sergey A. (Fayetteville, AR); Ponomareva, Inna V. (Fayetteville, AR); Kornev, Igor A. (Fayetteville, AR)
2009-09-22T23:59:59.000Z
A ferroelectric nanostructure formed as a low dimensional nano-scale ferroelectric material having at least one vortex ring of polarization generating an ordered toroid moment switchable between multi-stable states. A stress-free ferroelectric nanodot under open-circuit-like electrical boundary conditions maintains such a vortex structure for their local dipoles when subject to a transverse inhomogeneous static electric field controlling the direction of the macroscopic toroidal moment. Stress is also capable of controlling the vortex's chirality, because of the electromechanical coupling that exists in ferroelectric nanodots.
Sound Wave in Vortex with Sink
Soumen Basak
2003-11-17T23:59:59.000Z
Using Komar's definition, we give expressions for the mass and angular momentum of a rotating acoustic black hole. We show that the mass and angular momentum so defined, obey the equilibrium version of the first law of Black Hole thermodynamics. We also show that when a phonon passes by a vortex with a sink, its trajectory is bent. The angle of bending of the sound wave to leading order is quadratic in $A/cb$ and $B/cb$, where $b$ is the impact parameter and $A$ and $B$ are the parameters in the velocity of the fluid flow. The time delay in the propagation of sound wave which to first order depends only on $B/c^2$ and is independent of $A$.
Fuel injection of coal slurry using vortex nozzles and valves
Holmes, Allen B. (Rockville, MD)
1989-01-01T23:59:59.000Z
Injection of atomized coal slurry fuel into an engine combustion chamber is achieved at relatively low pressures by means of a vortex swirl nozzle. The outlet opening of the vortex nozzle is considerably larger than conventional nozzle outlets, thereby eliminating major sources of failure due to clogging by contaminants in the fuel. Control fluid, such as air, may be used to impart vorticity to the slurry and/or purge the nozzle of contaminants during the times between measured slurry charges. The measured slurry charges may be produced by a diaphragm pump or by vortex valves controlled by a separate control fluid. Fluidic circuitry, employing vortex valves to alternatively block and pass cool slurry fuel flow, is disclosed.
axisymmetric vortex breakdown: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Fluid Motion at the 66th Annual Meeting of the APS Division of Fluid Dynamics. Kleckner, Dustin; Irvine, William T M 2013-01-01 325 The Taylor-vortex dynamo Christophe Gissinger...
Vortex-induced vibration of slender structures in unsteady flow
Liao, Jung-Chi, 1971-
2002-01-01T23:59:59.000Z
Vortex-induced vibration (VIV) results in fatigue damage of offshore oil exploration and production structures. In recent years, the offshore industry has begun to employ curved slender structures such as steel catenary ...
Drag amplification and fatigue damage in vortex-induced vibrations
Jhingran, Vikas Gopal
2008-01-01T23:59:59.000Z
Fatigue damage and drag force amplification due to Vortex-Induced-Vibrations (VIV) continue to cause significant problems in the design of structures which operate in ocean current environments. These problems are magnified ...
Vortex hair on AdS black holes
Gregory, Ruth; Kubiznak, David; Mann, Robert B; Wills, Danielle
2014-01-01T23:59:59.000Z
We analyse vortex hair for charged rotating asymptotically AdS black holes in the abelian Higgs model. We give analytical and numerical arguments to show how the vortex interacts with the horizon of the black hole, and how the solution extends to the boundary. The solution is very close to the corresponding asymptotically flat vortex, once one transforms to a frame that is non-rotating at the boundary. We show that there is a Meissner effect for extremal black holes, with the vortex flux being expelled from sufficiently small black holes. The phase transition is shown to be first order in the presence of rotation, but second order without rotation. We comment on applications to holography.
Nonclassicality of vortex Airy beams in the Wigner representation
Chen Ruipin [School of Sciences, Zhejiang A and F University, Lin'an, Zhejiang Province 311300 (China); Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia); Ooi, C. H. Raymond [Department of Physics, University of Malaya, 50603 Kuala Lumpur (Malaysia)
2011-10-15T23:59:59.000Z
The Wigner distribution function (WDF) of a vortex Airy beam is calculated analytically. The WDF provides intuitive pictures of the intriguing features of vorticity in phase space. The nonclassical property of the vortex Airy beam and the Airy beam is analyzed through the negative parts of the WDF. The study shows that destructive interference of certain classical waves can mimic nonclassical lights such as those due to quantum effects.
Dissipative dynamics of a vortex state in a trapped Bose-condensed gas
P. O. Fedichev; G. V. Shlyapnikov
1999-06-15T23:59:59.000Z
We discuss dissipative dynamics of a vortex state in a trapped Bose-condensed gas at finite temperature and draw a scenario of decay of this state in a static trap. The interaction of the vortex with the thermal cloud transfers energy from the vortex to the cloud and induces the motion of the vortex core to the border of the condensate. Once the vortex reaches the border, it immediately decays through the creation of excitations. We calculate the characteristic life-time of a vortex state and address the question of how the dissipative dynamics of vortices can be studied experimentally.
Aghdaie, Bahman
2008-12-19T23:59:59.000Z
Engineering Management Field Project Conveying Cycle-Time Analysis in Pneumatic Conveying: A Study of Relationship between Batching & Convey Cycles in Powder & Bulk Handling Systems By Bahman Aghdaie Fall Semester, 2008...:_________________ Bahman Aghdaie EMGT-835 Field Project 2 Table of Contents Page Acknowledgements 4 Executive Summary 5 Chapter 1 - Introduction 7 Chapter 2 - Literature Review 9 Chapter 3 – Research Procedure 12...
AlAA 96-4505 RESULTS FROM INITIAL OPERATION OF A CONTINUOUS-FLOW,
Texas at Arlington, University of
Development Center. Descriptions of the arc heater, nozzle, test section, diffuser and vacuum tank; together, diffuser and vacuum tank; and the supporting DC power supply, cooling water system, pneumatic system employs a 2.0 MW, vortex-stabilized DC electric arc heater obtained from the Air Force Arnold Engineering
Vortex arrays and meso-scale turbulence of self-propelled particles
Robert Grossmann; Pawel Romanczuk; Markus Bär; Lutz Schimansky-Geier
2014-05-30T23:59:59.000Z
Inspired by the Turing mechanism for pattern formation, we propose a simple self-propelled particle model with short-ranged alignment and anti-alignment at larger distances. It is able to produce orientationally ordered states, periodic vortex patterns as well as meso-scale turbulence. The latter phase resembles observations in dense bacterial suspensions. The model allows a systematic derivation and analysis of a kinetic theory as well as hydrodynamic equations for density and momentum fields. A phase diagram with regions of such pattern formation as well as spatially homogeneous orientational order and disorder is obtained from a linear stability analysis of these continuum equations. Microscopic Langevin simulations of the self-propelled particle system are in agreement with these findings.
Alleviation of fuselage form drag using vortex flows: Final report
Wortman, A.
1987-09-15T23:59:59.000Z
The concept of using vortex generators to reduce the fuselage form drag of transport aircraft combines the outflow from the plane of symmetry which is induced by the rotational component of the vortex flow with the energization of the boundary layer to reduce the momentum thickness and to delay or eliminate flow separation. This idea was first advanced by the author in 1981. Under a DOE grant, the concept was validated in wind tunnel tests of approximately 1:17 scale models of fuselages of Boeing 747 and Lockheed C-5 aircraft. The search for the minimum drag involved three vortex generator configurations with three sizes of each in six locations clustered in the aft regions of the fuselages at the beginning of the tail upsweep. The local Reynolds number, which is referred to the length of boundary layer run from the nose, was approximately 10{sup 7} so that a fully developed turbulent boundary layer was present. Vortex generator planforms ranged from swept tapered, through swept straight, to swept reverse tapered wings whose semi-spans ranged from 50% to 125% of the local boundary layer thickness. Pitch angles of the vortex generators were varied by inboard actuators under the control of an external proportional digital radio controller. It was found that certain combinations of vortex generator parameters increased drag. However, with certain configurations, locations, and pitch angles of vortex generators, the highest drag reductions were 3% for the 747 and about 6% for the C-5, thus confirming the arguments that effectiveness increases with the rate of upsweep of the tail. Greatest gains in performance are therefore expected on aft loading military transports. 10 refs., 11 figs., 1 tab.
A PARAMETER STUDY FOR BAROCLINIC VORTEX AMPLIFICATION
Raettig, Natalie; Klahr, Hubert [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Lyra, Wladimir, E-mail: raettig@mpia.de, E-mail: klahr@mpia.de, E-mail: Wladimir.Lyra@jpl.nasa.gov [Department of Astrophysics, American Museum of Natural History, 79th Street at Central Park West, New York, NY 10024 (United States)
2013-03-10T23:59:59.000Z
Recent studies have shown that baroclinic vortex amplification is strongly dependent on certain factors, namely, the global entropy gradient, the efficiency of thermal diffusion and/or relaxation as well as numerical resolution. We conduct a comprehensive study of a broad range and combination of various entropy gradients, thermal diffusion and thermal relaxation timescales via local shearing sheet simulations covering the parameter space relevant for protoplanetary disks. We measure the Reynolds stresses as a function of our control parameters and see that there is angular momentum transport even for entropy gradients as low as {beta} = -dln s/dln r = 1/2. Values we expect in protoplanetary disks are between {beta} = 0.5-2.0 The amplification-rate of the perturbations, {Gamma}, appears to be proportional to {beta}{sup 2} and thus proportional to the square of the Brunt-Vaeisaelae frequency ({Gamma}{proportional_to}{beta}{sup 2}{proportional_to}N {sup 2}). The saturation level of Reynolds stresses, on the other hand, seems to be proportional to {beta}{sup 1/2}. This highlights the importance of baroclinic effects even for the low entropy gradients expected in protoplanetary disks.
Visualization of Intricate Flow Structures for Vortex Breakdown Analysis Xavier Tricoche
Utah, University of
Visualization of Intricate Flow Structures for Vortex Breakdown Analysis Xavier Tricoche University, synthetic depictions that permit new insight into the structural properties of vortex breakdowns. CR And Modeling-- Simulation Output Analysis J.2 [Physical Sciences and Engineer- ing]: Engineering--. Keywords
Experimental Investigations of Vortex Induced Vibration of A Flat Plate in Pitch Oscillation
Yang, Yi
2012-02-14T23:59:59.000Z
A bluff structure placed in a flowing fluid, may be subjected to vortex-induced vibrations (VIV). For a flat plate with only rotational degree of freedom, the VIV is rotational oscillation. Based on the experimental investigation, vortex...
X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation Print Magnetic thin-film nanostructures can exhibit a magnetic vortex state in which the magnetization vectors lie in...
Vortex in a relativistic perfect isentropic fluid and Nambu Goto dynamics
B. Boisseau
1999-11-26T23:59:59.000Z
By a weak deformation of the cylindrical symmetry of the potential vortex in a relativistic perfect isentropic fluid, we study the possible dynamics of the central line of this vortex. In "stiff" material the Nanbu-Goto equations are obtained
Mountziaris, T. J.
Vortex Shedding from Superhydrophobic Cylinders Nangelie Ferrer, Robert Daniello and Jonathan Rothstein University of Massachusetts Amherst Abstract Superhydrophobic surfaces are ideal for applications to characterize the vortex shedding phenomenon observed within the wake region of the superhydrophobic cylinder
Wave–vortex interactions in the nonlinear Schrödinger equation
Guo, Yuan, E-mail: yuanguo@cims.nyu.edu; Bühler, Oliver [Courant Institute of Mathematical Sciences, New York University, New York, New York 10012 (United States)] [Courant Institute of Mathematical Sciences, New York University, New York, New York 10012 (United States)
2014-02-15T23:59:59.000Z
This is a theoretical study of wave–vortex interaction effects in the two-dimensional nonlinear Schrödinger equation, which is a useful conceptual model for the limiting dynamics of superfluid quantum condensates at zero temperature. The particular wave–vortex interaction effects are associated with the scattering and refraction of small-scale linear waves by the straining flows induced by quantized point vortices and, crucially, with the concomitant nonlinear back-reaction, the remote recoil, that these scattered waves exert on the vortices. Our detailed model is a narrow, slowly varying wavetrain of small-amplitude waves refracted by one or two vortices. Weak interactions are studied using a suitable perturbation method in which the nonlinear recoil force on the vortex then arises at second order in wave amplitude, and is computed in terms of a Magnus-type force expression for both finite and infinite wavetrains. In the case of an infinite wavetrain, an explicit asymptotic formula for the scattering angle is also derived and cross-checked against numerical ray tracing. Finally, under suitable conditions a wavetrain can be so strongly refracted that it collapses all the way onto a zero-size point vortex. This is a strong wave–vortex interaction by definition. The conditions for such a collapse are derived and the validity of ray tracing theory during the singular collapse is investigated.
Passivity-Based Impact and Force Control of a Pneumatic Actuator
Barth, Eric J.
and coexistence of robots and humans not only on the shop floor, but also for applications at home the behavior of a simple impedance, then the stability of the system is preserved when it is coupled to the environment and/or a human operator. A system is said to be passive if the energy absorbed over any period
Vortex Interactions and Barotropic Aspects of Concentric Eyewall Formation HUNG-CHI KUO
Schubert, Wayne H.
of a tropical cyclone core with nearby weaker vorticity of various spatial scales. This paper considers, separation distance, companion vortex size, and core vortex skirt parameter. A vorticity skirt on the core6 times as strong as the larger companion vortex. An additional requirement is that the separation
Nonexistence of Lyapunov Functions and the Instability of the von Karman Vortex Streets
Lim, Chjan C.
Nonexistence of Lyapunov Functions and the Instability of the von Karman Vortex Streets Chjan Lim of the von Karman vortex streets and the existence of a global Lyapunov function at the special aspect ratio the equilibrium Karman streets are unlikely theoretical candidates for observed vortex trails. On the other hand
Hu, Hui
of the reverse von Karman vortex street behind the flapping wing. However, it is challenging to fully understandExperimental and Numerical Investigations on the Asymmetric Wake Vortex Structures around of the vortex pair becomes more apparent, which is considered to be a vital element to form the asymmetric wake
The effect of surface tension on the Moore singularity of vortex sheet dynamics
Fontelos, Marco
The effect of surface tension on the Moore singularity of vortex sheet dynamics F. de la Hoz , M's singularities by surface tension in the evolution of vortex sheets and its dependence on Weber number (which is inversely proportional to surface tension coefficient). The curvature of the vortex sheet, instead
Traveling Waves from the Arclength Parameterization: Vortex Sheets with Surface Tension
Wright, J. Douglas
Traveling Waves from the Arclength Parameterization: Vortex Sheets with Surface Tension Benjamin for the vortex sheet with surface tension. We use the angle- arclength description of the interface rather than prove that there exist traveling vortex sheets with surface tension bifurcating from equilibrium. We
Hydrodynamic loads on flexible marine structures due to vortex shedding
Every, M.J.; King, R.
1982-12-01T23:59:59.000Z
This paper makes a comparison of experimental measurements and a recently developed methodology for the prediction of the increase in the steady drag of a cylinder undergoing vortex-induced vibrations. The experimental results were obtained during the development of a means to reduce the flow-induced vibration of a cable-suspended pile of the COGNAC platform installation and agree well with the predictions made in this paper. Next, a brief consideration is made of some of the authors' experience of methods used to reduce vortex-induced vibrations, and hence stress levels. Finally, a reduction method which used an air-blowing manifold is described and results presented.
Wesfreid, José Eduardo
, concentrated vorticity can appear as a result of instabilities such as the BCnard-Von Karman vortex street vortex P. PETITJEANS `*, J. H. ROBRES a, J. E. WESFREID a, N. KEVLAHAN b ABSTRACT. - Experimental vortex (which is a non-confined stretched vortex model) are observed and analyzed, 0 Elsevier, Paris 1
Kervalishvili, N A
2015-01-01T23:59:59.000Z
The results of experimental investigations of inhomogeneities of gas-discharge nonneutral electron plasma obtained by using the nonperturbing experimental methods [N.A. Kervalishvili, arXiv:1502.02516 [physics.plasm-ph] (2015)] have been presented. Inhomogeneities are the dense solitary vortex structures stretched along the magnetic field, the lifetime of which is much greater than the time of electron-neutral collisions. The processes of formation, evolution and dynamics of vortex structures were studied. The periodic sequence of these processes is described for different geometries of discharge device.
Vortex phase-jitter in acoustically excited bluff body flames
Lieuwen, Timothy C.
Vortex phase-jitter in acoustically excited bluff body flames Santosh J. Shanbhogue, Michael disturbances. Phase locked particle image velocimetry was carried out over a range of conditions", manifested as cycle-to-cycle variation in flame and vorticity field at the same excitation phase. Phase
Onset of superradiant instabilities in the hydrodynamic vortex model
Shahar Hod
2014-07-30T23:59:59.000Z
The hydrodynamic vortex, an effective spacetime geometry for propagating sound waves, is studied analytically. In contrast with the familiar Kerr black-hole spacetime, the hydrodynamic vortex model is described by an effective acoustic geometry which has no horizons. However, this acoustic spacetime possesses an ergoregion, a property which it shares with the rotating Kerr spacetime. It has recently been shown numerically that this physical system is linearly unstable due to the superradiant scattering of sound waves in the ergoregion of the effective spacetime. In the present study we use analytical tools in order to explore the onset of these superradiant instabilities which characterize the effective spacetime geometry. In particular, we derive a simple analytical formula which describes the physical properties of the hydrodynamic vortex system in its critical (marginally-stable) state, the state which marks the boundary between stable and unstable fluid configurations. The analytically derived formula is shown to agree with the recently published numerical data for the hydrodynamic vortex system.
AXISYMMETRIC VORTEX BREAKDOWN IN AN ENCLOSED CYLINDER FLOW.
Lopez, John M.
into the interior flow from the Ekman boundary layer on the rotating endwall is observed, as is the formation,. The boundary conditions are also defined precisely since the flow is confined in a fixed volume. As Re and and the flow remains oscillatory. This oscillatory behavior is mostly confined to the central vortex region. 2
Modified Black Hole with Polar Jet and Vortex
T. Tmmalm
2001-12-06T23:59:59.000Z
There are many models relating an accretion disk of Black Hole to jet outflow. The herein heuristic model describes the continuation of an external accretion disk to an internal accretion disk for less than Black Hole horizon, and subsequent polar jet outflow along polar axis out of polar vortex wherein the event horizon is no longer descriptive.
Creation and pinning of vortex-antivortex pairs
Kim, Sangbum; Hu, Chia-Ren; Andrews, Malcolm J.
2006-01-01T23:59:59.000Z
Computer modeling is reported about the creation and pinning of a magnetic vortex-antivortex (V-AV) pair in a superconducting thin film, due to the magnetic field of a vertical magnetic dipole above the film, and two antidot pins inside the film...
LINEAR DISPERSIVE DECAY ESTIMATES FOR VORTEX SHEETS WITH SURFACE TENSION
Spirn, Daniel
governing irrotational vortex sheets and water waves with surface tension. Using oscillatory integral order, well- posedness theory poses difficulties; however, local-in-time existence for water waves by the kinematic condition in that the interface does not break. This implies the component of the velocity field
Vortex Shedding on Hydrofoils Its dark and lonely down there...
Vortex Shedding on Hydrofoils Its dark and lonely down there... Improving marine vehicle an underwater vehicle moves, it displaces water, genera6ng a unique velocity that it can u6lize rather than fight those flows, saving energy and improving
Inhomogeneous Vortex Patterns in Rotating Bose-Einstein Condensates
Correggi, Michele
2012-01-01T23:59:59.000Z
We consider a 2D rotating Bose gas described by the Gross-Pitaevskii (GP) theory and investigate the properties of the ground state of the theory for rotational speeds close to the critical speed for vortex nucleation. While one could expect that the vortex distribution should be homogeneous within the condensate we prove by means of an asymptotic analysis in the strongly interacting (Thomas-Fermi) regime that it is not. More precisely we rigorously derive a formula due to Sheehy and Radzihovsky [Phys. Rev. A 70, 063620(R) (2004)] for the vortex distribution, a consequence of which is that the vortex distribution is strongly inhomogeneous close to the critical speed and gradually homogeneizes when the rotation speed is increased. From the mathematical point of view, a novelty of our approach is that we do not use any compactness argument in the proof, but instead provide explicit estimates on the difference between the vorticity measure of the GP ground state and the minimizer of a certain renormalized energy...
Inhomogeneous Vortex Patterns in Rotating Bose-Einstein Condensates
Paris-Sud XI, UniversitÃ© de
be homogeneous within the condensate we prove by means of an asymptotic analysis in the strongly interactingInhomogeneous Vortex Patterns in Rotating Bose-Einstein Condensates M. Correggia , N. Rougerieb, France. May 10, 2012 Abstract We consider a 2D rotating Bose gas described by the Gross-Pitaevskii (GP
Inhomogeneous Vortex Patterns in Rotating Bose-Einstein Condensates
Paris-Sud XI, UniversitÃ© de
should be homogeneous within the condensate we prove by means of an asymptotic analysis in the stronglyInhomogeneous Vortex Patterns in Rotating Bose-Einstein Condensates M. Correggia , N. Rougerieb, France. September 19, 2012 Abstract We consider a 2D rotating Bose gas described by the Gross
Spacetime Defects: von Kármán vortex street like configurations
Patricio S. Letelier
2001-07-05T23:59:59.000Z
A special arrangement of spinning strings with dislocations similar to a von K\\'arm\\'an vortex street is studied. We numerically solve the geodesic equations for the special case of a test particle moving along twoinfinite rows of pure dislocations and also discuss the case of pure spinning defects.
R. M. W. van Bijnen; A. J. Dow; D. H. J. O'Dell; N. G. Parker; A. M. Martin
2009-05-10T23:59:59.000Z
We present a theoretical analysis of dilute gas Bose-Einstein condensates with dipolar atomic interactions under rotation in elliptical traps. Working in the Thomas-Fermi limit, we employ the classical hydrodynamic equations to first derive the rotating condensate solutions and then consider their response to perturbations. We thereby map out the regimes of stability and instability for rotating dipolar Bose-Einstein condensates and in the latter case, discuss the possibility of vortex lattice formation. We employ our results to propose several novel routes to induce vortex lattice formation in a dipolar condensate.
Pressurized water nuclear reactor system with hot leg vortex mitigator
Lau, Louis K. S. (Monroeville, PA)
1990-01-01T23:59:59.000Z
A pressurized water nuclear reactor system includes a vortex mitigator in the form of a cylindrical conduit between the hot leg conduit and a first section of residual heat removal conduit, which conduit leads to a pump and a second section of residual heat removal conduit leading back to the reactor pressure vessel. The cylindrical conduit is of such a size that where the hot leg has an inner diameter D.sub.1, the first section has an inner diameter D.sub.2, and the cylindrical conduit or step nozzle has a length L and an inner diameter of D.sub.3 ; D.sub.3 /D.sub.1 is at least 0.55, D.sub.2 is at least 1.9, and L/D.sub.3 is at least 1.44, whereby cavitation of the pump by a vortex formed in the hot leg is prevented.
Vortex energy and 360 Neel walls in thinfilm
.Ignat@math.u-psud.fr) Courant Institute, New York University, New York, NY 10012, USA (e-mail: knuepfer@cims.nyu.edu) 1 #12Vortex energy and 360 N´eel walls in thinfilm micromagnetics Radu Ignat , Hans Kn¨upfer October-section. The model is based on the following energy functional: E2d (m) = Z B2 |m|2 dx + | ln | 2 Z R2 ||-1
Reduction of the planar 4-vortex system at zero momentum
Patrick, George
in the plane the nth vortex has location zn = xn + iyn Ppl (C2 )N . The Hamiltonian and symplectic form- nally on each factor C of Ppl by (ei , a) Â· z ei z + a. A momentum mapping is Jpl - N n=1 n 1 2 |zn|2]. To calculate the quotient Âµe : (Jpl )-1 (Âµe) (Ppl )Âµe (Jpl )-1 (Âµe)/SE(2), one may first translate
Vortex energy and 360 Neel wall in thinfilm
Ignat, Radu
.Ignat@math.u-psud.fr) Courant Institute, New York University, New York, NY 10012, USA (e-mail: knuepfer@cims.nyu.edu) 1 #12Vortex energy and 360 N´eel wall in thinfilm micromagnetics Radu Ignat , Hans Kn¨upfer October-section. The model is based on the following energy functional: E2d (m) = Z B2 |m|2 dx + | ln | 2 Z R2 ||-1
High-precision calculations of vortex sheet motion
Ely, J.S. (Lewis and Clark College, Portland, OR (United States)); Baker, G.R. (Ohio State Univ., Columbus, OH (United States))
1994-04-01T23:59:59.000Z
The motion of a vortex sheet undergoing Kelvin-Helmholtz instability is known to be ill-posed, causing deterioration in numerical calculations from the rapid growth of round-off errors. In particular, it is the smallest scales (introduced by round-off) that grow the fastest. Krasny introduced a spectral filter to suppress the growth of round-off errors of the smallest scales. He was then able to detect evidence supporting asymptotic studies that indicate the formation of a curvature singularity in finite time. We use high precision interval arithmetic, coded in C + +, to re-examine the evolution of a vortex sheet from initial conditions used previously by several researchers. Most importantly, our results are free from the influence of round-off errors. We show excellent agreement between results obtained through high precision interval arithmetic and through the use of Krasny's spectral filter. In particular, our results support the formation of a curvature singularity in finite time. After the time of singularity formation, the markers move in peculiar patterns. We rule out any possibility of this motion resulting from round-off errors, but it does depend on the level of resolution. We find no consistent behavior in the motion of the markers as we improve the resolution of the vortex sheet. Also, we find some disagreement between the results obtained through high precision interval arithmetic and through the use of the spectral filter. 29 refs., 5 figs.
Corwin, Emily; Jagt, Katie; Neary, Leigh
2007-01-01T23:59:59.000Z
curves for Wildcat Creek. Evaluating the effects of vortexmap of Penitencia Creek………………………………………………………………10 Figure 6.Penitencia Creek site location………………………………………………………………….10
Corwin, Emily; Jagt, Katie; Neary, Leigh
2007-01-01T23:59:59.000Z
W. (2000). Urban Stream Restoration: An Initial Assessment.An increasing number of stream restoration projects include4 Introduction A common stream restoration practice involves
Stability of spiral wave vortex filaments with phase twists Keeyeol Nam,* Edward Ott,
Rubloff, Gary W.
. Guzdar, and Michael Gabbay Institute for Plasma Research, University of Maryland, College Park, Maryland
The time evolution of a vortex-flame interaction observed via planar imaging of CH and OH
Nguyen, Quang-Viet; Paul, P.H.
1996-05-01T23:59:59.000Z
Planar laser-induced fluorescence imaging diagnostics of OH and CH are used to examine a premixed laminar flame subjected to a strong line-vortex pair. Results are reported for a fuel-rcih lamiar CH{sub 4}-air-N{sub 2} rod-stabilized flame. The flow studied was highly reproducible, which enabled the use of phase-sampled imaging to provide time-resolved image sequences. Image sequences are shown for a condition sufficient to produce localized extinction of the primary flame. Results indicate that a breakage in the CH front is not preceded by any distinct change in the OH front. The structure of the CH and OH profiles during the transient leading up to, and through the breakage of the CH front do not appear to be consistent with the concept of a strained laminar flame.
Stability of a jet in crossflow
Ilak, Miloš; Bagheri, Shervin; Chevalier, Mattias; Henningson, Dan S
2010-01-01T23:59:59.000Z
We have produced a fluid dynamics video with data from Direct Numerical Simulation (DNS) of a jet in crossflow at several low values of the velocity inflow ratio R. We show that, as the velocity ratio R increases, the flow evolves from simple periodic vortex shedding (a limit cycle) to more complicated quasi-periodic behavior, before finally exhibiting asymmetric chaotic motion. We also perform a stability analysis just above the first bifurcation, where R is the bifurcation parameter. Using the overlap of the direct and the adjoint eigenmodes, we confirm that the first instability arises in the shear layer downstream of the jet orifice on the boundary of the backflow region just behind the jet.
Flayac, H.; Solnyshkov, D. D.; Malpuech, G.; Shelykh, I. A. [LASMEA, Clermont Universite-Universite Blaise Pascal, BP10448, 63000 Clermont-Ferrand (France); and LASMEA, CNRS, UMR 6602, 63177 Aubiere (France); Science Institute, University of Iceland, Dunhagi-3, IS-107 Reykjavik, Iceland and International Institute for Physics, Universidade Federal do Rio Grande do Norte (UFRN), Campus Universitario Lagoa Nova, CEP 59078-970 Natal, RN (Brazil)
2010-09-15T23:59:59.000Z
In a recent work [H. Flayac, I. A. Shelykh, D. D. Solnyshkov, and G. Malpuech, Phys. Rev. B 81, 045318 (2010)], we have analyzed the effect of the TE-TM splitting on the stability of the exciton-polariton vortex states. We considered classical vortex solutions having cylindrical symmetry and we found that the so-called half-vortex states [Yu. G. Rubo, Phys. Rev. Lett. 99, 106401 (2007)] are not solutions of the stationary Gross-Pitaevskii equation. In their Comment [Phys. Rev. B 82, 127301 (2010)], Toledo Solano and Rubo claim that this conclusion is misleading and claim to demonstrate the existence of static half-vortices in an exciton-polariton condensate in the presence of TE-TM splitting. In this Reply we explain why this assertion is not demonstrated satisfactorily.
Vortex-induced vibration of a circular cylinder with combined in-line and cross-flow motion
Dahl, Jason (Jason Michael)
2008-01-01T23:59:59.000Z
Deep water, string-like, marine risers subject to strong ocean currents, suffer from vortex-induced vibrations (VIV), where vortex shedding interacts with the structural properties of the riser, resulting in large amplitude ...
A model for universal time scale of vortex ring formation Kamran Mohseni
Mohseni, Kamran
and Applied Science, 104-44, California Institute of Technology, Pasadena, California 91125 Morteza Gharib Graduate Aeronautical Laboratory, California Institute of Technology, Pasadena, California 91125 Received of the fluid out of the cylinder and the approximation of the vortex at the pinch off moment by a vortex
Combustion in Meso-scale Vortex Chambers Ming-hsun Wu*
Yang, Vigor
1 Combustion in Meso-scale Vortex Chambers Ming-hsun Wu* , Yanxing Wang, Vigor Yang and Richard A) #12;2 COMBUSTION IN MESO-SCALE VORTEX CHAMBERS Ming-hsun Wu, Yanxing Wang, Vigor Yang and Richard A with the chemical energy varying from 25 to 174W. For the largest combustion volume, hydrogen and hydrocarbons
The geometric phase and the geometrodynamics of relativistic electron vortex beams
Pratul Bandyopadhyay; Banasri Basu; Debashree Chowdhury
2013-11-28T23:59:59.000Z
We have studied here the geometrodynamics of relativistic electron vortex beams from the perspective of the geometric phase associated with the scalar electron encircling the vortex line. It is pointed out that the electron vortex beam carrying orbital angular momentum is a natural consequence of the skyrmion model of a fermion. This follows from the quantization procedure of a fermion in the framework of Nelson's stochastic mechanics when a direction vector (vortex line) is introduced to depict the spin degrees of freedom. In this formalism a fermion is depicted as a scalar particle encircling a vortex line. It is here shown that when the Berry phase acquired by the scalar electron encircling the vortex line involves quantized Dirac monopole we have paraxial (non-paraxial) beam when the vortex line is parallel (orthogonal) to the wavefront propagation direction. Non-paraxial beams incorporate spin-orbit interaction. When the vortex line is tilted with respect to the propagation direction the Berry phase involves non-quantized monopole. The temporal variation of the direction of the tilted vortices is studied here taking into account the renormalization group flow of the monopole charge and it is predicted that this gives rise to spin Hall effect.
Determination of magnetic vortex chirality using lateral spin-valve and Y. Otani
Otani, Yoshichika
Determination of magnetic vortex chirality using lateral spin-valve geometry T. Kimuraa and Y October 2005 We demonstrate the determination of the vortex chirality using a nonlocal spin-valve measurement technique in a lateral spin valve consisting of a Permalloy Py disk 1 m in diameter and a Py wire
PHYSICAL REVIEW B 84, 144511 (2011) Rectification of vortex motion in a circular ratchet channel
Plourde, Britton L. T.
2011-01-01T23:59:59.000Z
PHYSICAL REVIEW B 84, 144511 (2011) Rectification of vortex motion in a circular ratchet channel N and induces a net vortex flow without any unbiased external drive, i.e., the ratchet effect. We show containing a single weak-pinning circular ratchet channel in a Corbino geometry and observed a substantial
Generalized London free energy for high-Tc vortex lattices Ian Affleck
Franz, Marcel
Generalized London free energy for high-Tc vortex lattices Ian Affleck Department of Physics-1829 97 50402-4 The London free energy provides a very simple way of studying the vortex lattice that this effect can arise from additional quartic derivative terms in the Ginzburg-Landau GL free energy47 or
FABRICATION ET TUDE D'UN MONOCRISTAL DE VORTEX DANS LE NIOBIUM SUPRACONDUCTEUR
Paris-Sud XI, Université de
447 FABRICATION ET ÉTUDE D'UN MONOCRISTAL DE VORTEX DANS LE NIOBIUM SUPRACONDUCTEUR P. THOREL. 2014 Nous étudions expérimentalement par diffraction de neutrons le réseau de vortex dans le niobium ce V-cristal est liée à celle des axes cristallins du niobium, étant donné la forte anisotropie des
GPU accelerated simulations of bluff body flows using vortex particle methods
Cottet, Georges-Henri
GPU accelerated simulations of bluff body flows using vortex particle methods Diego Rossinelli in press as: D. Rossinelli et al., GPU accelerated simulations of bluff body flows using vortex particle Penalization Bluff body flows a b s t r a c t We present a GPU accelerated solver for simulations of bluff body
Wei, John Y.T.
Lateral imaging of the superconducting vortex lattice using Doppler-modulated scanning tunneling on the quasiparticle tunneling spectrum, we have laterally imaged the vortex lattice in superconducting 2H-NbSe2 that circulates along the sample edge. Above the lower critical field, field can penetrate into the superconductor
Zero modes in vortex-fermion system with compact extra space
A. Nakamula; K. Shiraishi
2014-10-28T23:59:59.000Z
The existence of fermionic zero modes is shown in the presence of vortex configuration of pure $SU(2)$ gauge field on the manifold $M_4 \\times S^2$. From the perspective of four-dimensional effective theory, these zero modes are almost the same as the Jackiw-Rossi type zero modes of the vortex-fermion system.
Efficiently computing vortex lattices in fast rotating Bose-Einstein condensates Yanzhi Zhang1,2
Bao, Weizhu
Efficiently computing vortex lattices in fast rotating Bose-Einstein condensates Yanzhi Zhang1-Einstein condensates (BECs) with strongly repulsive interactions. The key ingredients of the method is to discretize method in time. Different vortex lattice structures of condensate ground state in two-dimensional (2D
Progress in year 2001 1. Observation of Vortex Lattices in Bose-Einstein Condensates
1 Progress in year 2001 1. Observation of Vortex Lattices in Bose-Einstein Condensates Quantized in rotating gaseous Bose-Einstein condensates (BEC) [2, 3]. We have observed the formation of highly-ordered vortex lattices in a rotating Bose- condensed gas [4]. They were produced by rotating the condensate
Influence of slip on vortex-induced motion of a superhydrophobic cylinder
Rothstein, Jonathan
Influence of slip on vortex-induced motion of a superhydrophobic cylinder Robert Daniello, Pranesh: Superhydrophobic Ultrahydrophobic Superhydrophobicity Slip Partial slip Drag reduction Vortex Cylinder a b s t r a c t The partial slip boundary condition produced by a superhydrophobic surface in the Cassie state
Elliptical-inertial instability of rotating Karman vortex streets A. Stegnera
Stegner Alexandre
Elliptical-inertial instability of rotating Karman vortex streets A. Stegnera Laboratoire de. Unlike the classical bidimensional Karman street, these observed vortex streets are affected by the earth Karman streets. A series of experiments were performed to study the wake of a cylinder in a rotating deep
Vortex ratchet effects in films with a periodic array of antidots Clcio C. de Souza Silva,1,
Moshchalkov, Victor V.
Vortex ratchet effects in films with a periodic array of antidots Clécio C. de Souza Silva,1, * J The vortex ratchet effect has been studied in Al films patterned with square arrays of submicron antidots. We. In addition, the experiments reveal interesting collective phenomena in the vortex ratchet effect. At fields
Hu, Hui
flapping motion is due to the reverse von Karman vortex street. Recently, Bohl and Koochesfahani1 haveAmerican Institute of Aeronautics and Astronautics 1 A Numerical Study of Vortex-Dominated Flow at the Reynolds (Re) number of 12600. The effects of the reduced frequency and Strouhal number on the wake vortex
Bluff Body Flow Simulation Using a Vortex Element Method
Anthony Leonard; Phillippe Chatelain; Michael Rebel
2004-09-30T23:59:59.000Z
Heavy ground vehicles, especially those involved in long-haul freight transportation, consume a significant part of our nation's energy supply. it is therefore of utmost importance to improve their efficiency, both to reduce emissions and to decrease reliance on imported oil. At highway speeds, more than half of the power consumed by a typical semi truck goes into overcoming aerodynamic drag, a fraction which increases with speed and crosswind. Thanks to better tools and increased awareness, recent years have seen substantial aerodynamic improvements by the truck industry, such as tractor/trailer height matching, radiator area reduction, and swept fairings. However, there remains substantial room for improvement as understanding of turbulent fluid dynamics grows. The group's research effort focused on vortex particle methods, a novel approach for computational fluid dynamics (CFD). Where common CFD methods solve or model the Navier-Stokes equations on a grid which stretches from the truck surface outward, vortex particle methods solve the vorticity equation on a Lagrangian basis of smooth particles and do not require a grid. They worked to advance the state of the art in vortex particle methods, improving their ability to handle the complicated, high Reynolds number flow around heavy vehicles. Specific challenges that they have addressed include finding strategies to accurate capture vorticity generation and resultant forces at the truck wall, handling the aerodynamics of spinning bodies such as tires, application of the method to the GTS model, computation time reduction through improved integration methods, a closest point transform for particle method in complex geometrics, and work on large eddy simulation (LES) turbulence modeling.
Vortex nozzle for segmenting and transporting metal chips from turning operations
Bieg, L.F.
1993-04-20T23:59:59.000Z
Apparatus for collecting, segmenting and conveying metal chips from machining operations utilizes a compressed gas driven vortex nozzle for receiving the chip and twisting it to cause the chip to segment through the application of torsional forces to the chip. The vortex nozzle is open ended and generally tubular in shape with a converging inlet end, a constant diameter throat section and a diverging exhaust end. Compressed gas is discharged through angled vortex ports in the nozzle throat section to create vortex flow in the nozzle and through an annular inlet at the entrance to the converging inlet end to create suction at the nozzle inlet and cause ambient air to enter the nozzle. The vortex flow in the nozzle causes the metal chip to segment and the segments thus formed to pass out of the discharge end of the nozzle where they are collected, cleaned and compacted as needed.
Flame-vortex interaction driven combustion dynamics in a backward-facing step combustor
Altay, H. Murat; Speth, Raymond L.; Hudgins, Duane E.; Ghoniem, Ahmed F. [Massachusetts Institute of Technology, Department of Mechanical Engineering, Cambridge, MA 02139 (United States)
2009-05-15T23:59:59.000Z
The combustion dynamics of propane-hydrogen mixtures are investigated in an atmospheric pressure, lean, premixed backward-facing step combustor. We systematically vary the equivalence ratio, inlet temperature and fuel composition to determine the stability map of the combustor. Simultaneous pressure, velocity, heat release rate and equivalence ratio measurements and high-speed video from the experiments are used to identify and characterize several distinct operating modes. When fuel is injected far upstream from the step, the equivalence ratio entering the flame is temporally and spatially uniform, and the combustion dynamics are governed only by flame-vortex interactions. Four distinct dynamic regimes are observed depending on the operating parameters. At high but lean equivalence ratios, the flame is unstable and oscillates strongly as it is wrapped around the large unsteady wake vortex. At intermediate equivalence ratios, weakly oscillating quasi-stable flames are observed. Near the lean blowout limit, long stable flames extending from the corner of the step are formed. At atmospheric inlet temperature, the unstable mode resonates at the 1/4 wavemode of the combustor. As the inlet temperature is increased, the 5/4 wavemode of the combustor is excited at high but lean equivalence ratios, forming the high-frequency unstable flames. Higher hydrogen concentration in the fuel and higher inlet temperatures reduce the equivalence ratios at which the transitions between regimes are observed. We plot combustion dynamics maps or the response curves, that is the overall sound pressure level as a function of the equivalence ratio, for different operating conditions. We demonstrate that numerical results of strained premixed flames can be used to collapse the response curves describing the transitions among the dynamic modes onto a function of the heat release rate parameter alone, rather than a function dependent on the equivalence ratio, inlet temperature and fuel composition separately. We formulate a theory for predicting the critical values of the heat release parameter at which quasi-stable to unstable and unstable to high-frequency unstable modes take place. (author)
Magnetic Vortex Core Reversal by Low-Field Excitations
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9November 6, InaprilU .Magnetic Vortex Core
Magnetic Vortex Core Reversal by Low-Field Excitations
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9November 6, InaprilU .Magnetic Vortex CoreMagnetic
Magnetic Vortex Core Reversal by Low-Field Excitations
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9November 6, InaprilU .Magnetic Vortex
Magnetic Vortex Core Reversal by Low-Field Excitations
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9November 6, InaprilU .Magnetic VortexMagnetic
Magnetic Vortex Core Reversal by Low-Field Excitations
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9November 6, InaprilU .MagneticMagnetic Vortex Core
Magnetic Vortex Core Reversal by Low-Field Excitations
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of Science (SC)Integrated Codes |IsLove Your Home and It'll Love YouTokamak| NationalMagnetic Vortex
Wiese, E. C.
1998-12-11T23:59:59.000Z
The Building 200/205 Pneumatic Transfer Tube D&D Project was directed toward the following goals: Remove any radioactive and hazardous materials associated with the transfer tube; Survey the transfer tube to identify any external contamination; Remove the transfer tube and package for disposal; Survey the soil and sand surrounding the transfer tube for any contamination; and Backfill the trench in which the tube sat and restore the area to its original condition. These goals had been set in order to eliminate the radiological and hazardous safety concerns inherent in the buried transfer tube and to allow, upon completion of the project, the removal of this project from the ANL-E action item list. The physical condition of the transfer tube and possible nuclear fuel samples lost in the tube were the primary areas of concern, while the exact location of the transfer tube was of secondary concern. ANL-E health physics technicians collected characterization data from the ends of the Building 200/205 pneumatic transfer tube in January 1998. The characterization surveys identified contamination to a level of 67,000 dpm (1,117 Bq) ({beta}/{gamma}) and 20,000 dpm (333 Bq) {alpha} smearable at the opening.
The Relation Between Dry Vortex Merger and Tropical Cyclone Genesis over the Atlantic Ocean
Chen, Shu-Hua; Liu, Yi-Chin
2014-10-27T23:59:59.000Z
A strong, convective African tropical disturbance has a greater chance to develop into a Tropical 23 Depression (TD) if it merges with a shallow, dry vortex (D-vortex) from the north of the African 24 easterly jet (AEJ) after leaving the western coast. Using 11-year reanalysis data we found that the 25 western tip of a vortex strip at northwestern Africa can serve as dry vortices for the D-vortex 26 merger if it shifts southward. Another source of D-vortices is the westward propagating lows 27 along the southern edge of the Saharan air. The D-vortex merger process occurred for 63.5% of 28 tropical cyclones (TCs) or developing systems over the main development region of the Atlantic 29 Ocean, while it occurred for 54% of non-developing systems. TC genesis could be largely 30 controlled by the large-scale environment, but the differences in characteristics of vortices 31 associated with the D-vortex merger between developing and non-developing systems could 32 potentially help determine their destinies; in general, developing systems were dominated by a 33 more intense and moist south vortex, while non-developing systems were dominated by a north 34 vortex which was more intense, drier, and larger in size. Analysis also shows that 74% of intense 35 developing systems were involved with the D-vortex merger process. More attention needs to be 36 paid to the D-vortex merger and the characteristics of those vortices as they can play significant 37 roles or have a strong indication in Atlantic TC genesis.
Magnetic response of holographic Lifshitz superconductors:Vortex and Droplet solutions
Arindam Lala
2014-07-04T23:59:59.000Z
In this paper a holographic model of $s$-wave superconductor with anisotropic Lifshitz scaling has been considered. In the presence of an external magnetic field our holographic model exhibits both vortex and droplet solutions. Based on analytic methods we have shown that the anisotropy has no effect on the vortex and droplet solutions whereas it may affect the condensation. Our vortex solution closely resembles the Ginzburg-Landau theory and a relation between the upper critical magnetic field and superconducting coherence length has been speculated from this comparison. Using Sturm-Liouville method, the effect of anisotropy on the critical parameters in insulator/superconductor phase transitions has been analyzed.
Decay of helical Kelvin waves on a quantum vortex filament
Van Gorder, Robert A., E-mail: rav@knights.ucf.edu [Department of Mathematics, University of Central Florida, Orlando, Florida 32816-1364 (United States)
2014-07-15T23:59:59.000Z
We study the dynamics of helical Kelvin waves moving along a quantum vortex filament driven by a normal fluid flow. We employ the vector form of the quantum local induction approximation (LIA) due to Schwarz. For an isolated filament, this is an adequate approximation to the full Hall-Vinen-Bekarevich-Khalatnikov dynamics. The motion of such Kelvin waves is both translational (along the quantum vortex filament) and rotational (in the plane orthogonal to the reference axis). We first present an exact closed form solution for the motion of these Kelvin waves in the case of a constant amplitude helix. Such solutions exist for a critical wave number and correspond exactly to the Donnelly-Glaberson instability, so perturbations of such solutions either decay to line filaments or blow-up. This leads us to consider helical Kelvin waves which decay to line filaments. Unlike in the case of constant amplitude helical solutions, the dynamics are much more complicated for the decaying helical waves, owing to the fact that the rate of decay of the helical perturbations along the vortex filament is not constant in time. We give an analytical and numerical description of the motion of decaying helical Kelvin waves, from which we are able to ascertain the influence of the physical parameters on the decay, translational motion along the filament, and rotational motion, of these waves (all of which depend nonlinearly on time). One interesting finding is that the helical Kelvin waves do not decay uniformly. Rather, such waves decay slowly for small time scales, and more rapidly for large time scales. The rotational and translational velocity of the Kelvin waves depend strongly on this rate of decay, and we find that the speed of propagation of a helical Kelvin wave along a quantum filament is large for small time while the wave asymptotically slows as it decays. The rotational velocity of such Kelvin waves along the filament will increase over time, asymptotically reaching a finite value. These decaying Kelvin waves correspond to wave number below the critical value for the Donnelly-Glaberson instability, and hence our results on the Schwarz quantum LIA correspond exactly to what one would expect from prior work on the Donnelly-Glaberson instability.
Gas turbine engine combustor can with trapped vortex cavity
Burrus, David Louis; Joshi, Narendra Digamber; Haynes, Joel Meier; Feitelberg, Alan S.
2005-10-04T23:59:59.000Z
A gas turbine engine combustor can downstream of a pre-mixer has a pre-mixer flowpath therein and circumferentially spaced apart swirling vanes disposed across the pre-mixer flowpath. A primary fuel injector is positioned for injecting fuel into the pre-mixer flowpath. A combustion chamber surrounded by an annular combustor liner disposed in supply flow communication with the pre-mixer. An annular trapped dual vortex cavity located at an upstream end of the combustor liner is defined between an annular aft wall, an annular forward wall, and a circular radially outer wall formed therebetween. A cavity opening at a radially inner end of the cavity is spaced apart from the radially outer wall. Air injection first holes are disposed through the forward wall and air injection second holes are disposed through the aft wall. Fuel injection holes are disposed through at least one of the forward and aft walls.
Vortex flow in the technology of radiation wave cracking (RWC)
L. A. Tsoy; V. N. Kolushov; A. G. Komarov; A. N. Tsoy
2012-09-16T23:59:59.000Z
This article examines the theory of vortex flows in relation to the processes occurring in the radiation-wave cracking of crude oil, when the crude oil is sprayed into the gas stream in the form of a mist and then is fed into the reactor, where it is treated by the accelerated electrons and the UHF radiation. The output of this process are the products with the specified parameters (high-octane petroleum products). This process operates at the ambient pressure and temperature, which makes the process safer for industrial purposes. Besides the process itself, the authors described the equipment used in this process, as well as the parameters of the optimal process.
Exact moduli space metrics for hyperbolic vortex polygons
Krusch, S. [School of Mathematics, Statistics and Actuarial Science, University of Kent, Canterbury CT2 7NF (United Kingdom); Speight, J. M. [Department of Pure Mathematics, University of Leeds, Leeds LS2 9JT (United Kingdom)
2010-02-15T23:59:59.000Z
Exact metrics on some totally geodesic submanifolds of the moduli space of static hyperbolic N-vortices are derived. These submanifolds, denoted as {sigma}{sub n,m}, are spaces of C{sub n}-invariant vortex configurations with n single vortices at the vertices of a regular polygon and m=N-n coincident vortices at the polygon's center. The geometric properties of {sigma}{sub n,m} are investigated, and it is found that {sigma}{sub n,n-1} is isometric to the hyperbolic plane of curvature -(3{pi}n){sup -1}. The geodesic flow on {sigma}{sub n,m} and a geometrically natural variant of geodesic flow recently proposed by Collie and Tong ['The dynamics of Chern-Simons vortices', Phys. Rev. D Part. Fields Gravit. Cosmol. 78, 065013 (2008);e-print arXiv:hep-th/0805.0602] are analyzed in detail.
Vortex and gap generation in gauge models of graphene
O. Oliveira; C. E. Cordeiro; A. Delfino; W. de Paula; T. Frederico
2011-04-22T23:59:59.000Z
Effective quantum field theoretical continuum models for graphene are investigated. The models include a complex scalar field and a vector gauge field. Different gauge theories are considered and their gap patterns for the scalar, vector, and fermion excitations are investigated. Different gauge groups lead to different relations between the gaps, which can be used to experimentally distinguish the gauge theories. In this class of models the fermionic gap is a dynamic quantity. The finite-energy vortex solutions of the gauge models have the flux of the "magnetic field" quantized, making the Bohm-Aharonov effect active even when external electromagnetic fields are absent. The flux comes proportional to the scalar field angular momentum quantum number. The zero modes of the Dirac equation show that the gauge models considered here are compatible with fractionalization.
Vortex life cycles in two-and three-layer quasi-geostrophic models
Fox, Amanda Katherine
2000-01-01T23:59:59.000Z
Coherent vortices and their properties were studied in two- and three-layer quasi-geostrophic beta-plane turbulence. Much research has discussed vortex characteristics in a number of applications, but no significant study of vortices in turbulent...
On the vortex parameter estimation using wide band signals in active acoustic system
Paris-Sud XI, Université de
is an important operation in a large number of applications such as turbine monitoring, de- tection of a vortex in a closed hydraulic test loop. The objective of the work is to emphasize the effect
Falling, flapping, flying, swimming,... : high-Re fluid-solid interactions with vortex shedding
Michelin, Sébastien Honoré Roland
2009-01-01T23:59:59.000Z
Meckh. , 1, 79–86. Krasny, R. , 1986a: Desingularisation ofJ. Comp. Phys. , 65, 292–313. Krasny, R. , 1986b: A study ofvortex sheet equation (Krasny, 1986a,b). The vortex sheet
Under consideration for publication in J. Fluid Mech. 1 Mixing in a vortex breakdown flow
Paris-Sud XI, Université de
& Kohlman 1971; Hall 1972; Lowson & Riley 1995) where it creates a sudden drop of the lift and an increase the core of the vortex. Artificial tornadoes within a chimney have been proposed as a way of converting
The vortex merger rate in freely decaying, two-dimensional turbulence J. H. LaCascea
LaCasce, Joseph H.
vortex models in which energy-conserving mergers were allowed. Trizac19 used a molecular dynamics in laboratory experiments in which vortices were generated by electromagnetic excitation in an electrolyte.10
A Model of Compressor Blade Row Interaction with Shock Induced Vortex Shedding
Cincinnati, University of
A Model of Compressor Blade Row Interaction with Shock Induced Vortex Shedding Mark G. Turner = circulation = trailing edge thickness = shock angle = density I. Introduction ransonic compressor stages AIAA. Research Scientist, Compressor Aerodynamic Research Laboratory, Associate Fellow AIAA
Hierarchical Colloidal Vortex Rings in a Constant Electric Field Yilong Han and David G. Grier
Grier, David
15 1050 15 (b) (c) (d) (e) packed close- core vortex ring (d) (e)(b) (c) (a) (f) corona t [sec] Rg) tracking its radius of gyration Rg over time. spheres is surrounded by a diffuse circulating corona
Hierarchical Colloidal Vortex Rings in a Constant Electric Field Yilong Han and David G. Grier
Grier, David
15 10 5 0 15 (b) (c) (d) (e) packed close- core vortex ring (d) (e) (b) (c) (a) (f) corona t [sec] Rg corona that extends outward for tens of micrometers. Although these clusters somewhat resemble
Kim, S.; Hu, Chia-Ren; Andrews, MJ.
2004-01-01T23:59:59.000Z
that the system passes through nearly metastable intermediate configurations while seeking the final minimum-energy steady state consistent with the square symmetry of the sample. An efficient scheme to determine the equilibrium vortex configuration in a...
Effect of traveling waves on Vortex-Induced Vibration of long flexible cylinders
Jaiswal, Vivek, Ph. D. Massachusetts Institute of Technology
2009-01-01T23:59:59.000Z
Offshore marine risers and pipelines, exposed to ocean currents, are susceptible to Vortex-Induced Vibration (VIV). Accurate prediction of VIV is necessary for estimating the fatigue life as well as for taking corrective ...
Interaction between magnetic vortex cores in a pair of nonidentical nanodisks
Sinnecker, J. P.; Vigo-Cotrina, H.; Garcia, F.; Novais, E. R. P.; Guimarães, A. P., E-mail: apguima@cbpf.br [Centro Brasileiro de Pesquisas Físicas, 22290-180, Rio de Janeiro, Rio de Janeiro (Brazil)
2014-05-28T23:59:59.000Z
The coupling of two nonidentical magnetic nanodisks, i.e., with different vortex gyrotropic frequencies, is studied. From the analytical approach, the interactions between the nanodisks along x and y directions (the coupling integrals) were obtained as a function of distance. From the numerical solution of Thiele's equation, we derived the eigenfrequencies of the vortex cores as a function of distance. The motion of the two vortex cores and, consequently, the time dependence of the total magnetization M(t) were derived both using Thiele's equation and by micromagnetic simulation. From M(t), a recently developed method, the magnetic vortex echoes, analogous to the Nuclear Magnetic Resonance spin echoes, was used to compute the distance dependence of the magnetic coupling strength. The results of the two approaches differ by approximately 10%; using one single term, a dependence with distance found is broadly in agreement with studies employing other techniques.
Interacting vortex pairs in inviscid and viscous planar flows Thierry Gallay
Gallay, Thierry
Interacting vortex pairs in inviscid and viscous planar flows Thierry Gallay Universitâ??e de Grenoble I Institut Fourier, UMR CNRS 5582 B.P. 74 FÂ38402 SaintÂMartinÂd'Hâ??eres, France Thierry.Gallay
Interacting vortex pairs in inviscid and viscous planar flows Thierry Gallay
Gallay, Thierry
Interacting vortex pairs in inviscid and viscous planar flows Thierry Gallay UniversitÂ´e de Grenoble I Institut Fourier, UMR CNRS 5582 B.P. 74 F-38402 Saint-Martin-d'H`eres, France Thierry.Gallay
Mukundan, Harish
2008-01-01T23:59:59.000Z
Vortex-induced vibration (VIV) of long flexible cylindrical structures enduring ocean currents is ubiquitous in the offshore industry. Though significant effort has gone into understanding this complicated fluid-structure ...
Vortex-induced vibration of flexible cylinders in time-varying flows
Resvanis, Themistocles L
2014-01-01T23:59:59.000Z
This thesis investigates two aspects of Vortex-Induced Vibrations (VIV) on long flexible cylinders. The work is split into a minor and major part. The minor part addresses the effect of Reynolds number on flexible cylinder ...
Vortex Induced Vibrations of cylinders : experiments in reducing drag force and amplitude of motion
Farrell, David Emmanuel
2007-01-01T23:59:59.000Z
Reducing the deleterious effect of Vortex Induced Vibrations (VIV) in marine risers is an important task for ocean engineers; and many competing factors exist in the design of VIV suppression devices. This thesis explores ...
Vortex-induced vibrations of a long flexible cylinder in shear flow
Triantafyllou, Michael S.
We investigate the in-line and cross-flow vortex-induced vibrations of a long cylindrical tensioned beam, with length to diameter ratio L/D = 200, placed within a linearly sheared oncoming flow, using three-dimensional ...
Enhancement of vortex induced forces and motion through surface roughness control
Bernitsas, Michael M. (Saline, MI); Raghavan, Kamaldev (Houston, TX)
2011-11-01T23:59:59.000Z
Roughness is added to the surface of a bluff body in a relative motion with respect to a fluid. The amount, size, and distribution of roughness on the body surface is controlled passively or actively to modify the flow around the body and subsequently the Vortex Induced Forces and Motion (VIFM). The added roughness, when designed and implemented appropriately, affects in a predetermined way the boundary layer, the separation of the boundary layer, the level of turbulence, the wake, the drag and lift forces, and consequently the Vortex Induced Motion (VIM), and the fluid-structure interaction. The goal of surface roughness control is to increase Vortex Induced Forces and Motion. Enhancement is needed in such applications as harnessing of clean and renewable energy from ocean/river currents using the ocean energy converter VIVACE (Vortex Induced Vibration for Aquatic Clean Energy).
Vortex in a weakly relativistic Bose gas at zero temperature and relativistic fluid approximation
B. Boisseau
2004-09-14T23:59:59.000Z
The Bogoliubov procedure in quantum field theory is used to describe a relativistic almost ideal Bose gas at zero temperature. Special attention is given to the study of a vortex. The radius of the vortex in the field description is compared to that obtained in the relativistic fluid approximation. The Kelvin waves are studied and, for long wavelengths, the dispersion relation is obtained by an asymptotic matching method and compared with the non relativistic result.
The universal criterion for switching a magnetic vortex core in soft magnetic nanodots
Lee, K.-S.; Kim, S.-K.; Yu, Y.-S.; Choi, Y.-S.; Guslienko, K. Y.; Jung, H.; Fischer, P.
2008-10-01T23:59:59.000Z
The universal criterion for ultrafast vortex core switching between core-up and -down vortex bi-states in soft magnetic nanodots was empirically investigated by micromagnetic simulations and combined with an analytical approach. Vortex-core switching occurs whenever the velocity of vortex core motion reaches a critical value, which is {nu}{sub c} = 330 {+-} 37 m/s for Permalloy, as estimated from numerical simulations. This critical velocity was found to be {nu}{sub c} = {eta}{sub c}{gamma} {radical}A{sub ex} with A{sub ex} the exchange stiffness, {gamma} the gyromagnetic ratio, and an estimated proportional constant {eta}{sub c} = 1.66 {+-} 0.18. This criterion does neither depend on driving force parameters nor on the dimension or geometry of the magnetic specimen. The phase diagrams for the vortex core switching criterion and its switching time with respect to both the strength and angular frequency of circular rotating magnetic fields were derived, which offer practical guidance for implementing vortex core switching into future solid state information storage devices.
Liu Zhao; Guo Hongli; Fan Heng [Institute of Physics, Chinese Academy of Sciences, Beijing 100190 (China); Vedral, Vlatko [Clarendon Laboratory, University of Oxford, Parks Road, Oxford OX1 3PU (United Kingdom); Centre for Quantum Technologies, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore); Department of Physics, National University of Singapore, 2 Science Drive 3, Singapore 117542 (Singapore)
2011-01-15T23:59:59.000Z
We use entanglement to investigate the transition from vortex-liquid phase to vortex-lattice phase in a weakly interacting rotating Bose-Einstein condensate. For the torus geometry, the ground-state entanglement spectrum is analyzed to distinguish these two phases. The low-lying part of the ground-state entanglement spectrum, as well as the behavior of its lowest level, changes clearly when the transition occurs. For the sphere geometry, the entanglement gap in the conformal limit is also studied. We also show that the decrease in entanglement between particles can be regarded as a signal of the transition.
Klein, Avraham [The Racah Institute of Physics, The Hebrew University of Jerusalem, 91904 (Israel); Aleiner, Igor L., E-mail: aleiner@phys.columbia.edu [Physics Department, Columbia University, New York, NY 10027 (United States); Agam, Oded [The Racah Institute of Physics, The Hebrew University of Jerusalem, 91904 (Israel); Physics Department, Columbia University, New York, NY 10027 (United States)
2014-07-15T23:59:59.000Z
We analyze the motion of quantum vortices in a two-dimensional spinless superfluid within Popov’s hydrodynamic description. In the long healing length limit (where a large number of particles are inside the vortex core) the superfluid dynamics is determined by saddle points of Popov’s action, which, in particular, allows for weak solutions of the Gross–Pitaevskii equation. We solve the resulting equations of motion for a vortex moving with respect to the superfluid and find the reconstruction of the vortex core to be a non-analytic function of the force applied on the vortex. This response produces an anomalously large dipole moment of the vortex and, as a result, the spectrum associated with the vortex motion exhibits narrow resonances lying within the phonon part of the spectrum, contrary to traditional view.
Ahsan Choudhuri
2011-03-31T23:59:59.000Z
Turbine combustors of advanced power systems have goals to achieve very low pollutants emissions, fuel variability, and fuel flexibility. Future generation gas turbine combustors should tolerate fuel compositions ranging from natural gas to a broad range of syngas without sacrificing operational advantages and low emission characteristics. Additionally, current designs of advanced turbine combustors use various degrees of swirl and lean premixing for stabilizing flames and controlling high temperature NOx formation zones. However, issues of fuel variability and NOx control through premixing also bring a number of concerns, especially combustor flashback and flame blowout. Flashback is a combustion condition at which the flame propagates upstream against the gas stream into the burner tube. Flashback is a critical issue for premixed combustor designs, because it not only causes serious hardware damages but also increases pollutant emissions. In swirl stabilized lean premixed turbine combustors onset of flashback may occur due to (i) boundary layer flame propagation (critical velocity gradient), (ii) turbulent flame propagation in core flow, (iii) combustion instabilities, and (iv) upstream flame propagation induced by combustion induced vortex breakdown (CIVB). Flashback due to first two foregoing mechanisms is a topic of classical interest and has been studied extensively. Generally, analytical theories and experimental determinations of laminar and turbulent burning velocities model these mechanisms with sufficient precision for design usages. However, the swirling flow complicates the flashback processes in premixed combustions and the first two mechanisms inadequately describe the flashback propensity of most practical combustor designs. The presence of hydrogen in syngas significantly increases the potential for flashback. Due to high laminar burning velocity and low lean flammability limit, hydrogen tends to shift the combustor operating conditions towards flashback regime. Even a small amount of hydrogen in a fuel blend triggers the onset of flashback by altering the kinetics and thermophysical characteristics of the mixture. Additionally, the presence of hydrogen in the fuel mixture modifies the response of the flame to the global effects of stretch and preferential diffusion. Despite its immense importance in fuel flexible combustor design, little is known about the magnitude of fuel effects on CIVB induced flashback mechanism. Hence, this project investigates the effects of syngas compositions on flashback resulting from combustion induced vortex breakdown. The project uses controlled experiments and parametric modeling to understand the velocity field and flame interaction leading to CIVB driven flashback.
Vortex loops: Are they always doomed to die
Ben-Ya'acov, U. (International Solvay Institutes for Physics and Chemistry, Campus Plaine-CP231, Universite Libre de Bruxelles, Boulevard du Triomphe, B-1050 Brussels (Belgium))
1995-03-15T23:59:59.000Z
The effective equations of motion of relativistic strings in material media are derived and applied to moving rings with a time-dependent radius. The equations contain the Magnus force, due to the motion of the ring relative to the medium, whose eventual effect is the possible stabilization of the ring against shrinking. A constant solution is identified, and small fluctuations around it are bound, demonstrating the stability of the solution. If the string loops created in the cosmological cosmic string scenario interact via this mechanism with a formed-up Higgs particle condensate, then the stabilizing velocities are [similar to][delta][sub loop]/[ital R][sub loop], and the overall effect of this phenomenon is to stabilize large loops and reduce the general disappearance rate of the string loops.
Longitudinal Stability Calculations
Blaskiewicz,M.
2009-01-02T23:59:59.000Z
Coupled bunch longitudinal stability in the presence of high frequency impedances is considered. A frequency domain technique is developed and compared with simulations. The frequency domain technique allows for absolute stability tests and is applied to the problem of longitudinal stability in RHIC with the new 56 MHz RF system.
B. Boisseau
1999-01-18T23:59:59.000Z
From a recent study of a stationary cylindrical solution for a relativistic two-constituent superfluid at low temperature limit, we propose to specify this solution under the form of a relativistic generalisation of a Rankine vortex (Potential vortex whose the core has a solid body rotation).Then we establish the dynamics of the central line of this vortex by supposing that the deviation from the cylindrical configuration is weak in the neighbourhood of the core of the vortex. In "stiff" material the Nambu-Goto equations are obtained.
The London theory of the crossing-vortex lattice in highly anisotropic layered superconductors
S. E. Savel'ev; J. Mirkovic; K. Kadowaki
2001-05-18T23:59:59.000Z
A novel description of Josephson vortices (JVs) crossed by the pancake vortices (PVs) is proposed on the basis of the anisotropic London theory. The field distribution of a JV and its energy have been calculated for both dense ($a\\lambda_J$) PV lattices with distance $a$ between PVs, and the nonlinear JV core size $\\lambda_J$. It is shown that the ``shifted'' PV lattice (PVs displaced mainly along JVs in the crossing vortex lattice structure), formed in high out-of-plane magnetic fields transforms into the PV lattice ``trapped'' by the JV sublattice at a certain field, lower than $\\Phi_0/\\gamma^2s^2$, where $\\Phi_0$ is the flux quantum, $\\gamma$ is the anisotropy parameter and $s$ is the distance between CuO$_2$ planes. With further decreasing $B_z$, the free energy of the crossing vortex lattice structure (PV and JV sublattices coexist separately) can exceed the free energy of the tilted lattice (common PV-JV vortex structure) in the case of $\\gamma s<\\lambda_{ab}$ with the in-plane penetration depth $\\lambda_{ab}$ if the low ($B_x<\\gamma\\Phi_0/\\lambda_{ab}^2$) or high ($B_x\\gtrsim \\Phi_0/\\gamma s^2$) in-plane magnetic field is applied. It means that the crossing vortex structure is realized in the intermediate field orientations, while the tilted vortex lattice can exist if the magnetic field is aligned near the $c$-axis and the $ab$-plane as well. In the intermediate in-plane fields $\\gamma\\Phi_0/\\lambda_{ab}^2\\lesssim B_x \\lesssim \\Phi_0/\\gamma s^2$, the crossing vortex structure with the ``trapped'' PV sublattice seems to settle in until the lock-in transition occurs since this structure has the lower energy with respect to the tilted vortex structure in the magnetic field ${\\vec H}$ oriented near the $ab$-plane.
Vortex generation in protoplanetary disks with an embedded giant planet
M. de Val-Borro; P. Artymowicz; G. D'Angelo; A. Peplinski
2007-06-21T23:59:59.000Z
Vortices in protoplanetary disks can capture solid particles and form planetary cores within shorter timescales than those involved in the standard core-accretion model. We investigate vortex generation in thin unmagnetized protoplanetary disks with an embedded giant planet with planet to star mass ratio $10^{-4}$ and $10^{-3}$. Two-dimensional hydrodynamical simulations of a protoplanetary disk with a planet are performed using two different numerical methods. The results of the non-linear simulations are compared with a time-resolved modal analysis of the azimuthally averaged surface density profiles using linear perturbation theory. Finite-difference methods implemented in polar coordinates generate vortices moving along the gap created by Neptune-mass to Jupiter-mass planets. The modal analysis shows that unstable modes are generated with growth rate of order $0.3 \\Omega_K$ for azimuthal numbers m=4,5,6, where $\\Omega_K$ is the local Keplerian frequency. Shock-capturing Cartesian-grid codes do not generate very much vorticity around a giant planet in a standard protoplanetary disk. Modal calculations confirm that the obtained radial profiles of density are less susceptible to the growth of linear modes on timescales of several hundreds of orbital periods. Navier-Stokes viscosity of the order $\
Topological superconductivity, topological confinement, and the vortex quantum Hall effect
Diamantini, M. Cristina; Trugenberger, Carlo A. [INFN and Dipartimento di Fisica, University of Perugia, via A. Pascoli, I-06100 Perugia (Italy); SwissScientific, chemin Diodati 10, CH-1223 Cologny (Switzerland)
2011-09-01T23:59:59.000Z
Topological matter is characterized by the presence of a topological BF term in its long-distance effective action. Topological defects due to the compactness of the U(1) gauge fields induce quantum phase transitions between topological insulators, topological superconductors, and topological confinement. In conventional superconductivity, because of spontaneous symmetry breaking, the photon acquires a mass due to the Anderson-Higgs mechanism. In this paper we derive the corresponding effective actions for the electromagnetic field in topological superconductors and topological confinement phases. In topological superconductors magnetic flux is confined and the photon acquires a topological mass through the BF mechanism: no symmetry breaking is involved, the ground state has topological order, and the transition is induced by quantum fluctuations. In topological confinement, instead, electric charge is linearly confined and the photon becomes a massive antisymmetric tensor via the Stueckelberg mechanism. Oblique confinement phases arise when the string condensate carries both magnetic and electric flux (dyonic strings). Such phases are characterized by a vortex quantum Hall effect potentially relevant for the dissipationless transport of information stored on vortices.
OTEC cold water pipe design for problems caused by vortex-excited oscillations
Griffin, O. M.
1980-03-14T23:59:59.000Z
Vortex-excited oscillations of marine structures result in reduced fatigue life, large hydrodynamic forces and induced stresses, and sometimes lead to structural damage and to diestructive failures. The cold water pipe of an OTEC plant is nominally a bluff, flexible cylinder with a large aspect ratio (L/D = length/diameter), and is likely to be susceptible to resonant vortex-excited oscillations. The objective of this report is to survey recent results pertaining to the vortex-excited oscillations of structures in general and to consider the application of these findings to the design of the OTEC cold water pipe. Practical design calculations are given as examples throughout the various sections of the report. This report is limited in scope to the problems of vortex shedding from bluff, flexible structures in steady currents and the resulting vortex-excited oscillations. The effects of flow non-uniformities, surface roughness of the cylinder, and inclination to the incident flow are considered in addition to the case of a smooth cyliner in a uniform stream. Emphasis is placed upon design procedures, hydrodynamic coefficients applicable in practice, and the specification of structural response parameters relevant to the OTEC cold water pipe. There are important problems associated with in shedding of vortices from cylinders in waves and from the combined action of waves and currents, but these complex fluid/structure interactions are not considered in this report.
A Robust Numerical Method for Integration of Point-Vortex Trajectories in Two Dimensions
Spencer A. Smith; Bruce M. Boghosian
2010-11-19T23:59:59.000Z
The venerable 2D point-vortex model plays an important role as a simplified version of many disparate physical systems, including superfluids, Bose-Einstein condensates, certain plasma configurations, and inviscid turbulence. This system is also a veritable mathematical playground, touching upon many different disciplines from topology to dynamic systems theory. Point-vortex dynamics are described by a relatively simple system of nonlinear ODEs which can easily be integrated numerically using an appropriate adaptive time stepping method. As the separation between a pair of vortices relative to all other inter-vortex length scales decreases, however, the computational time required diverges. Accuracy is usually the most discouraging casualty when trying to account for such vortex motion, though the varying energy of this ostensibly Hamiltonian system is a potentially more serious problem. We solve these problems by a series of coordinate transformations: We first transform to action-angle coordinates, which, to lowest order, treat the close pair as a single vortex amongst all others with an internal degree of freedom. We next, and most importantly, apply Lie transform perturbation theory to remove the higher-order correction terms in succession. The overall transformation drastically increases the numerical efficiency and ensures that the total energy remains constant to high accuracy.
Numerical study of Kelvin-Helmholtz instability by the point vortex method
Krasny, R.
1983-01-01T23:59:59.000Z
Rosenhead's classical point vortex numerical method for studying the evolution of a vortex sheet from analytic initial data (Kelvin-Helmholtz instability) is examined using the discrete Fourier analysis techniques of Sulem, Sulem and Frisch. One cause for the chaotic motion previously observed in computations using a large number of vortices is that short wavelength perturbations are introduced spuriously by finite precision arithmetic and become amplified by the model's dynamics. Methods for controlling this source of error are given, and the results confirm the formation of a singularity in a finite time which was previously found by Moore and Meiron, Baker and Orszag using different techniques of analysis. A cusp forms in the vortex sheet strength at the critical time, explaining the onset of erratic particle motion in applications of the numerical methods of Van de Vooren and Fink and Soh to this problem. Unlike those methods, the point vortex approximation remains consistent at the critical time and results of a long time calculation are presented. The singularity is interpreted physically as a discontinuity in the strain rate along the vortex sheet and also as the start of roll up on a small scale. The author numerically studies some aspects of the dependence of the solution on the initial condition and finds agreement with Moore's asymptotic relation between the initial amplitude and the critial time.
van Hemmen, J. Leo
that pass a fish later- ally [19] as well as vortex rings that are part of a von Ka´rma´n vortex street [20 by the lateral-line sensors so as to enable fish to follow a vortex street. DOI: 10.1103/PhysRevLett.103Wake Tracking and the Detection of Vortex Rings by the Canal Lateral Line of Fish Jan-Moritz P
Paris-Sud XI, Université de
Femtosecond laser fabrication of micro and nano-disks in single layer graphene using vortex Bessel deposition graphene on glass substrate using femtosecond laser ablation with vortex Bessel beams. The fabricated graphene disks with diameters ranging from 650 nm to 4 µm were characterized by spatially resolved
Joule heating induced by vortex motion in a type-II superconductor Z. L. Xiao and E. Y. Andrei
Andrei, Eva Y.
Joule heating induced by vortex motion in a type-II superconductor Z. L. Xiao and E. Y. Andrei-II superconductor due to Joule heating induced by vortex motion. The effect of Joule heating is detected s duration, where the Joule heating is negligible and saturates, respectively. The thermometry is based
Boyer, Edmond
Bow-wave-like hydraulic jump and horseshoe vortex around an obstacle in a supercritical open the obstacle, two main flow structures are observed: i a hydraulic jump in the near-surface region and ii turbulent regime , the detachment length of the hydraulic jump exceeds the one of the horseshoe vortex
Vortex dipoles by PIV method Click here to see the images and the short movies from this lab
deYoung, Brad
Introduction A vortex dipole is a jet flow with a system of two vortices of opposite sign at its front. Vortex of density stratification. The simplest case of stratification is a two-layer system. A Plexiglas tank a two-layer system without mixing the fluids, one can float a sheet of paper on top of the salt water
Dunin-Borkowski, Rafal E.
transformations.7 Recent experimental reports confirm these predictions of domain wall movement8Quantitative determination of vortex core dimensions in head-to-head domain walls using off-dimensional characterization of vortex core spin structures, which is important for future magnetic data storage based
Raychaudhuri, Pratap
Role of the Vortex-Core Energy on the Berezinskii-Kosterlitz-Thouless Transition in Thin Films-Kosterlitz-Thouless (BKT) transition in thin films of NbN at various film thickness, by probing the effect of vortex played by the vortex-core energy in determining the characteristic signatures of the BKT physics, and we
Mohseni, Kamran
field around a fish's body in the presence of a Karman vortex street. Karman and reverse Karman streets LLTC model could explain how a fish identifies the characteristics of a Karman vortex street shed that the main characteristics of a vortex street including the magnitude of vortices, their translational speed
Reduction of vortex induced forces and motion through surface roughness control
Bernitsas, Michael M; Raghavan, Kamaldev
2014-04-01T23:59:59.000Z
Roughness is added to the surface of a bluff body in a relative motion with respect to a fluid. The amount, size, and distribution of roughness on the body surface is controlled passively or actively to modify the flow around the body and subsequently the Vortex Induced Forces and Motion (VIFM). The added roughness, when designed and implemented appropriately, affects in a predetermined way the boundary layer, the separation of the boundary layer, the level of turbulence, the wake, the drag and lift forces, and consequently the Vortex Induced Motion (VIM), and the fluid-structure interaction. The goal of surface roughness control is to decrease/suppress Vortex Induced Forces and Motion. Suppression is required when fluid-structure interaction becomes destructive as in VIM of flexible cylinders or rigid cylinders on elastic support, such as underwater pipelines, marine risers, tubes in heat exchangers, nuclear fuel rods, cooling towers, SPAR offshore platforms.
Vortex combustor for low NOX emissions when burning lean premixed high hydrogen content fuel
Steele, Robert C; Edmonds, Ryan G; Williams, Joseph T; Baldwin, Stephen P
2012-11-20T23:59:59.000Z
A trapped vortex combustor. The trapped vortex combustor is configured for receiving a lean premixed gaseous fuel and oxidant stream, where the fuel includes hydrogen gas. The trapped vortex combustor is configured to receive the lean premixed fuel and oxidant stream at a velocity which significantly exceeds combustion flame speed in a selected lean premixed fuel and oxidant mixture. The combustor is configured to operate at relatively high bulk fluid velocities while maintaining stable combustion, and low NOx emissions. The combustor is useful in gas turbines in a process of burning synfuels, as it offers the opportunity to avoid use of diluent gas to reduce combustion temperatures. The combustor also offers the possibility of avoiding the use of selected catalytic reaction units for removal of oxides of nitrogen from combustion gases exiting a gas turbine.
Random Vortex-Street Model for a Self-Similar Plane Turbulent Jet
Victor L'vov; Anna Pomyalov; Itamar Procaccia; Rama Govindarajan
2008-03-18T23:59:59.000Z
We ask what determines the (small) angle of turbulent jets. To answer this question we first construct a deterministic vortex-street model representing the large scale structure in a self-similar plane turbulent jet. Without adjustable parameters the model reproduces the mean velocity profiles and the transverse positions of the large scale structures, including their mean sweeping velocities, in a quantitative agreement with experiments. Nevertheless the exact self similar arrangement of the vortices (or any other deterministic model) necessarily leads to a collapse of the jet angle. The observed (small) angle results from a competition between vortex sweeping tending to strongly collapse the jet and randomness in the vortex structure, with the latter resulting in a weak spreading of the jet.
Shear Banding and Spatiotemporal Oscillations in Vortex Matter in Nanostructured Superconductors
C. Reichhardt; C. J. Olson Reichhardt
2009-12-16T23:59:59.000Z
We propose a simple nanostructured pinning array geometry where a rich variety of complex vortex shear banding phenomena can be realized. A single row of pinning sites is removed from a square pinning array. Shear banding effects arise when vortex motion in the pin-free channel nucleates motion of vortices in the surrounding pinned regions, creating discrete steps in the vortex velocity profile away from the channel. Near the global depinning transition, the width of the band of moving vortices undergoes oscillations or fluctuations that can span the entire system. We use simulations to show that these effects should be observable in the transport properties of the system. Similar large oscillations and shear banding effects are known to occur for sheared complex fluids in which different dynamical phases coexist.
Vortex combustor for low NOx emissions when burning lean premixed high hydrogen content fuel
Steele, Robert C. (Woodinville, WA); Edmonds, Ryan G. (Renton, WA); Williams, Joseph T. (Kirkland, WA); Baldwin, Stephen P. (Winchester, MA)
2009-10-20T23:59:59.000Z
A trapped vortex combustor. The trapped vortex combustor is configured for receiving a lean premixed gaseous fuel and oxidant stream, where the fuel includes hydrogen gas. The trapped vortex combustor is configured to receive the lean premixed fuel and oxidant stream at a velocity which significantly exceeds combustion flame speed in a selected lean premixed fuel and oxidant mixture. The combustor is configured to operate at relatively high bulk fluid velocities while maintaining stable combustion, and low NOx emissions. The combustor is useful in gas turbines in a process of burning synfuels, as it offers the opportunity to avoid use of diluent gas to reduce combustion temperatures. The combustor also offers the possibility of avoiding the use of selected catalytic reaction units for removal of oxides of nitrogen from combustion gases exiting a gas turbine.
Crain, J.S.; Kiely, J.T.
1995-08-01T23:59:59.000Z
Dilute nitric acid blanks and solutions containing Ni, Cd, Pb, and U (including two laboratory waste samples) were analyzed eighteen times over a two-month period using inductively coupled plasma-mass spectrometry (ICP-MS). Two different sample introduction techniques were employed: flow injection-direct injection nebulization (FI-DIN) and continuous pneumatic nebulization (CPN). Using comparable instrumental measurement procedures, FI-DIN analyses were 33% faster and generated 52% less waste than CPN analyses. Instrumental limits of detection obtained with FI-DIN and CPN were comparable but not equivalent (except in the case of Pb) because of nebulizer-related differences in sensitivity (i.e., signal per unit analyte concentration) and background. Substantial and statistically significant differences were found between FI-DIN and CPN Ni determinations, and in the case of the laboratory waste samples, there were also small but statistically significant differences between Cd determinations. These small (2 to 3%) differences were not related to polyatomic ion interference (e.g., {sup 95}Mo{sup 16}O{sup +}), but in light of the time savings and waste reduction to be realized, they should not preclude the use of FI-DIN in place of CPN for determination of Cd, Pb, U and chemically.
Estimating dispersion from a tornado vortex and mesocyclone
Weber, A.H.; Hunter, C.H.
1996-06-01T23:59:59.000Z
Atmospheric dispersion modeling is required to ensure that a postulated breach in radionuclide storage containers at the Savannah River Site (SRS) from a tornado strike of Fujita-scale intensity F2 or higher will not result in an unacceptable dose to individuals. Fujita-scale tornado descriptions are included in Appendix A of this report. Dispersion models previously used at SRS for estimating dispersion following a tornado strike were developed by D.W. Pepper in 1975 (DP-1387, Dispersion of Small Particles) and H.R. Haynes and D.W. Taylor in 1983 (DPST-82-982, Estimating Doses from Tornado Winds). Research conducted in 1983 on the formation and evolution of tornadic thunderstorms has lead to a more complete understanding of the tornado vortex and associated persistent updraft and downdraft regions within the parent thunderstorm. To ensure that appropriate, contemporary methods are used for safety analysis, the Pepper model and the Haynes and Taylor model were evaluated with respect to current knowledge of circulations within tornadic thunderstorms. Pepper`s model is complex numerically but contains most of the desired physical parameterizations. Haynes and Taylor`s model is used with the Puff-Plume model (an emergency response model on the Weather INformation and Display System at SRS) and has provisions for radionuclide deposition and rainout. Haynes and Taylor assumed heavy rain following the tornado for a period of ten minutes, followed by a lighter rain for another ten minutes, then no rain for the period when the material is transported to 100 km downwind. However, neither model incorporates the effects of a nearby thunderstorm downdraft.
Formation of multi-solitons and vortex bright solitons in Bose-condensed alkali-metal atoms
Luca Salasnich
2003-09-02T23:59:59.000Z
Formation of multi-solitons and vortex bright solitons in Bose-condensed alkali-metal atoms is analyzed by using the nonpolynomial Schordinger equation. A train of bright solitons is obtained from an axially homogeneous Bose-Einstein condensate by a sudden change of the scattering length from repulsive to attractive. We derive an analytical expression for the number of bright solitons generated by using this mechanism. The formula generalizes a previous formula obtained with the 1D Gross-Pitaevskii equation. In the second part we consider vortex bright solitons, namely cigar-shaped bright solitons with a nonzero angular quantum number $k$ along the axial direction. By using a variational approach we determine the shape of vortex bright solitons, showing that the critical number of atoms for the collapse of the vortex soliton increases with a larger $k$. Finally we calculate monopole and quadrupole collective oscillations of these vortex bright solitons.
Numerical study of Kelvin-Helmholtz instability by the point vortex method
Krasny, R.
1983-12-01T23:59:59.000Z
Rosenhead's classical point vortex numerical method for studying the evolution of a vortex sheet from analytic initial data (Kelvin-Helmholtz instability) is examined using the discrete Fourier analysis techniques of Sulem, Sulem and Frisch. One cause for the chaotic motion previously observed in computations using a large number of vortices is that short wavelength perturbations are introduced spuriously by finite precision arithmetic and become amplified by the model's dynamics. Methods for controlling this source of error are given and the results confirm the formation of a singularity in a finite time which was previously found by Moore and Meiron, Baker and Orszag using different techniques of analysis. A cusp forms in the vortex sheet strength at the critical time, explaining the onset of erratic particle motion in applications of the numerical methods of Van de Vooren and Fink and Soh to this problem. Unlike those methods, the point vortex approximation remains consistent at the critical time and we present the results of a long time calculation. The singularity is interpreted physically as a discontinuity in the strain rate along the vortex sheet and also as the start of roll up on a small scale. We numerically study some aspects of the dependence of the solution on the initial condition and find agreement with Moore's asymptotic relation between the initial amplitude and the critical time. For large initial amplitudes, two cusps form in the sheet strength, corresponding to double roll up. We explain why the Poincare recurrenc theorem does not imply that the sheet will eventually unroll. Our results suggest that beyond the critical time, the vortex sheet becomes a spiral with infinite arclength although we have doubts about the approximation's accuracy in that regime. 36 references, 30 figures, 3 tables.
The effects of a jet on vortex breakdown over a sharp leading-edge delta wing
Maynard, Ian Kenneth
1985-01-01T23:59:59.000Z
THE EFFECTS OF A JET ON VORTEX BREAKDOWN OVER A SHARP LEADING-EDGE DELTA WING A Thesis Submitted to the Graduate College of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE December 1985... Major Subject: Aerospace Engineering THE EFFECTS OF A JET ON VORTEX BREAKDOWN OVER A SHARP LEADING-EDGE DELTA WING A Thesis by IAN KENNETH MAYNARD Approved as to style and content by: Cyrus Ostowar (Chairman of Committee) Stan J Miley (M er...
Streamline topology and dilute particle dynamics in a Karman vortex street flow
Wu, Z B
2003-01-01T23:59:59.000Z
Three types of streamline topology in a Karman vortex street flow are shown under the variation of spatial parameters. For the motion of dilute particles in the K\\'arm\\'an vortex street flow, there exist a route of bifurcation to a chaotic orbit and more attractors in a bifurcation diagram for the proportion of particle density to fluid density. Along with the increase of spatial parameters in the flow filed, the bifurcation process is suspended, as well as more and more attractors emerge. In the motion of dilute particles, a drag term and gravity term dominate and result in the bifurcation phenomenon.
Anderson, Jonas T., E-mail: jonastyleranderson@gmail.com
2013-03-15T23:59:59.000Z
In this paper we define homological stabilizer codes on qubits which encompass codes such as Kitaev's toric code and the topological color codes. These codes are defined solely by the graphs they reside on. This feature allows us to use properties of topological graph theory to determine the graphs which are suitable as homological stabilizer codes. We then show that all toric codes are equivalent to homological stabilizer codes on 4-valent graphs. We show that the topological color codes and toric codes correspond to two distinct classes of graphs. We define the notion of label set equivalencies and show that under a small set of constraints the only homological stabilizer codes without local logical operators are equivalent to Kitaev's toric code or to the topological color codes. - Highlights: Black-Right-Pointing-Pointer We show that Kitaev's toric codes are equivalent to homological stabilizer codes on 4-valent graphs. Black-Right-Pointing-Pointer We show that toric codes and color codes correspond to homological stabilizer codes on distinct graphs. Black-Right-Pointing-Pointer We find and classify all 2D homological stabilizer codes. Black-Right-Pointing-Pointer We find optimal codes among the homological stabilizer codes.
Stabilized radio frequency quadrupole
Lancaster, Henry D. (Orinda, CA); Fugitt, Jock A. (Berkeley, CA); Howard, Donald R. (Danville, CA)
1984-01-01T23:59:59.000Z
A long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator.
Effect of asymmetric axial strain on the behavior of the juncture vortex system
Trosper, Jeffrey Randall
1994-01-01T23:59:59.000Z
The objective of this research was to investigate the behavior of the vortex formed in a wing-body juncture in a water tunnel flow. The wing-body juncture was created by mounting a symmetrical airfoil with an elliptical leading edge normal to a flat...
A Lagrangian approach to identifying vortex pinch-off Clara O'Farrell1
Dabiri, John O.
A Lagrangian approach to identifying vortex pinch-off Clara O'Farrell1 and John O. Dabiri2 1 Control and Dynamical Systems, California Institute of Technology, Pasadena, California 91125, USA 2 Graduate Aeronautical Laboratories and Bioengineering, California Institute of Technology, Pasadena
Crown copyright Met Office Hurricane dynamics: on the role of Vortex Rossby Waves (VRWs).
© Crown copyright Met Office Hurricane dynamics: on the role of Vortex Rossby Waves (VRWs). Gilbert of numerical weather prediction: hurricanes, typhoons and tropical cyclones · Hurricane intensity · Conclusion #12;© Crown copyright Met Office Hurricane Juan, 28 September 2003, Halifax 75°N 110°W 10°E5°N
Indirect Combustion Noise: Experimental Investigation of the Vortex Sound Generation in a Choked
Paris-Sud XI, Université de
Indirect Combustion Noise: Experimental Investigation of the Vortex Sound Generation in a Choked-27 April 2012, Nantes, France 2315 #12;Combustion noise in gas turbines consists of direct noise related to the unsteady combustion process itself and indirect noise. As known, indirect noise is produced when entropy
Observations of wave-generated vortex ripples on the North Carolina continental shelf
Kirby, James T.
October 2002. [1] Sand ripples with wavelengths between 0.5 and 3 m were observed on the bottom across, 1882; Forel, 1883; Dingler, 1974; Vincent and Osborne, 1993; Gallagher et al., 1998; Traykovski et al ripples'' by Bagnold [1946], exert a much larger drag on the flow than friction on sand grains. Vortex
Simulation of vortex sheet roll-up: chaos, azimuthal waves, ring merger
Krasny, Robert
Simulation of vortex sheet roll-up: chaos, azimuthal waves, ring merger Robert KRASNY1 , Keith-1109 USA krasny@umich.edu National Center for Atmospheric Research, Climate andGlobal Dynamics Boulder, axisymmetric, and three- dimensional flow Krasny &Nitsche 2001; Lindsay & Krasny 2001. Vor- tex sheet
On the bifurcation structure of axisyrnmetric vortex breakdown in a constricted pipe
Lopez, John M.
On the bifurcation structure of axisyrnmetric vortex breakdown in a constricted pipe J. M. Lopez Department of Mathematics and Earth SystemScienceCenter;The PennsylvaniaState University, Universiv Park, Pennsylvania 16802 (Received 5 April 1994; accepted 20 July 1994) The bifurcation structure is presented
Complex Langevin simulation of quantum vortex nucleation in the Bose-Einstein condensate
Tomoya Hayata; Arata Yamamoto
2014-11-19T23:59:59.000Z
The ab-initio simulation of quantum vortex nucleation in the Bose-Einstein condensate is performed by adopting the complex Langevin techniques. We simulate the two-component boson field theory at a finite chemical potential under rotation. In the superfluid phase, vortices are generated above a critical angular velocity and the circulation is clearly quantized even in the presence of quantum fluctuations.
Rakowski, Cynthia L.; Richmond, Marshall C.; Serkowski, John A.
2006-12-01T23:59:59.000Z
A computational fluid dynamics (CFD) model was used in an investigation into the suppression of a surface vortex that forms and the south-most spilling bay at The Dalles Project. The CFD work complemented work at the prototype and the reduced-scale physical models. The CFD model was based on a model developed for other work in the forebay but had additional resolution added near the spillway. Vortex suppression devices (VSDs) were to placed between pier noses and/or in the bulkhead slot of the spillway bays. The simulations in this study showed that placing VSD structures or a combination of structures to suppress the vortex would still result in near-surface flows to be entrained in a vortex near the downstream spillwall. These results were supported by physical model and prototype studies. However, there was a consensus of the fish biologists at the physical model that the fish would most likely move north and if the fish went under the VSD it would immediately exit the forebay through the tainter gate and not get trapped between VSDs or the VSDs and the tainter gate if the VSDs were deep enough.
Wavelet analysis of vortex breakdown Jori E. Ruppert-Felsot1
École Normale Supérieure
Wavelet analysis of vortex breakdown Jori E. Ruppert-Felsot1 , Marie Farge1 , and Philippe the experimentally mea- sured flow field using orthogonal wavelets to observe the time evolution of the bursting. The discrete wavelet transform is used to separate the flow field into a coherent component, capturing
2094 OPTICS LETTERS / Vol. 28, No. 21 / November 1, 2003 Fundamental and vortex solitons in a
Yang, Jianke
2094 OPTICS LETTERS / Vol. 28, No. 21 / November 1, 2003 Fundamental and vortex solitons in a two-dimensional optical lattice Jianke Yang Department of Mathematics and Statistics, University of Vermont, Burlington-dimensional optically induced waveguide array are reported. In the strong localization regime the fundamental soliton
Vortex Ring Interaction with a Particle Layer: Implications for Sediment Transport
Dalziel, Stuart
resuspension has been studied much less. This is an important mechanism, however, as it represents an integral conducted to study particle resuspension by vortex rings colliding with a particle bed. The dynamics at the resuspension onset are investigated, showing that the deformable particle bed resembles a free slip boundary
Reduced gravity rankine cycle design and optimization with passive vortex phase separation
Supak, Kevin Robert
2009-05-15T23:59:59.000Z
Interphase Transport Phenomena kW(e) Kilowatts-Electric MVS Microgravity Vortex Separator ORNL Oak Ridge National Laboratory SNAP Systems For Nuclear Auxiliary Power MPRE Medium Power Reactor Experiment RFMD Rotary Fluid Management Device RPM...............................................................................................3 History of Space Rankine Cycle Development .....................................6 ORNL Rankine Cycle Design..............................................................10 Space Rankine Cycle Components...
Supak, Kevin Robert
2008-10-10T23:59:59.000Z
Interphase Transport Phenomena kW(e) Kilowatts-Electric MVS Microgravity Vortex Separator ORNL Oak Ridge National Laboratory SNAP Systems For Nuclear Auxiliary Power MPRE Medium Power Reactor Experiment RFMD Rotary Fluid Management Device RPM...............................................................................................3 History of Space Rankine Cycle Development .....................................6 ORNL Rankine Cycle Design..............................................................10 Space Rankine Cycle Components...
Vortex Liquid Crystals in Anisotropic Type II Superconductors E.W. Carlson,1,2
Carlson, Erica
Vortex Liquid Crystals in Anisotropic Type II Superconductors E.W. Carlson,1,2 A. H. Castro Neto,1 September 2002; published 25 February 2003) In an isotropic type II superconductor in a moderate magnetic been much interest in high tem- perature superconductors in a magnetic field. Various ex- periments
Two regimes of vortex penetration into platelet-shaped type-II superconductors
Brandt, E. H. [Max-Planck-Institut fuer Metallforschung (Germany)] [Max-Planck-Institut fuer Metallforschung (Germany); Mikitik, G. P., E-mail: mikitik@ilt.kharkov.ua [Ukrainian Academy of Sciences, Verkin Institute for Low Temperature Physics and Engineering (Ukraine); Zeldov, E. [Weizmann Institute of Science, Department of Condensed Matter Physics (Israel)] [Weizmann Institute of Science, Department of Condensed Matter Physics (Israel)
2013-09-15T23:59:59.000Z
Vortex penetration into a thin superconducting strip of a rectangular cross section is considered at an increasing applied magnetic field H{sub a}, taking an interplay between the Bean-Livingston and the geometric barriers in the sample into account. We calculate the magnetic field H{sub p} at which the penetration begins and show that two regimes of vortex penetration are possible. In the first regime, vortices appearing at the corners of the strip at H{sub a} = H{sub p} immediately move to its center, where a vortex dome starts to develop. In the second regime, the penetration occurs in two stages. In the first stage, at H{sub a} < H{sub p}, tilted vortices penetrate into the edge regions of the strip, where novel domes are shown to be formed at the top, bottom, and lateral surfaces. In the second stage, at H{sub a} = H{sub p}, the vortex propagation to the center becomes possible. The difference between the regimes manifests itself in slightly different dependences of the magnetic moment of the strip on H{sub a}.
Origin of Reversed Vortex Ratchet Motion W. Gillijns, A. V. Silhanek, and V. V. Moshchalkov
Moshchalkov, Victor V.
Origin of Reversed Vortex Ratchet Motion W. Gillijns, A. V. Silhanek, and V. V. Moshchalkov INPAC. This rectified motion of particles, known as a rocked ratchet, is basically the result of the broken spatial that the particles (flux lines) cannot be regarded as independent entities leads to a far richer ratchet motion
Evolution of an initially columnar vortex terminating normal to a no-slip wall
Lopez, John M.
Èdewadt-type spatially oscillatory boundary layer within the core region and a potential-like vortex boundary layer at large radii. The toroidal structure results from the interaction between these two boundary layers's theo- retical study only applied to the boundary layer formed away from the core, as have most other
BAROCLINIC VORTICITY PRODUCTION IN PROTOPLANETARY DISKS. II. VORTEX GROWTH AND LONGEVITY
Julien, Keith
BAROCLINIC VORTICITY PRODUCTION IN PROTOPLANETARY DISKS. II. VORTEX GROWTH AND LONGEVITY Mark R -- instabilities -- methods: numerical -- solar system: formation -- turbulence Online material: color figures 1 the surface. Thus, the potential energy of the tilted isopycnals is converted into the kinetic energy
Vortex avalanches with robust statistics observed in superconducting niobium E. Altshuler,1,2
Zeldov, Eli
Vortex avalanches with robust statistics observed in superconducting niobium E. Altshuler,1,2 T. H topography of superconducting niobium samples as the external field is slowly increased. The avalanche size in Ref. 11, was quite limited, being based on only a few hundred events. Nowak et al.12 studied niobium
Vortex-Pair Dynamics in Anisotropic Bistable Media: A Kinematic Approach Aric Hagberg1
Hagberg, Aric
Vortex-Pair Dynamics in Anisotropic Bistable Media: A Kinematic Approach Aric Hagberg1 and Ehud typically evolves into rotating spiral waves. In an anisotropic system, instead of spiral waves, the vortices can form wave fragments that propagate with a constant speed in a given direction determined
Particle resuspension by an impacting vortex ring RICK J. MUNRO & STUART B. DALZIEL
Dalziel, Stuart
Particle resuspension by an impacting vortex ring RICK J. MUNRO & STUART B. DALZIEL Department results from a set of visualization experiments conducted to analyse the hydrodynamic resuspension of particles from a thick horizontal sediment layer. The mechanism employed to produce the resuspension
Resuspension onset and crater erosion by a vortex ring interacting with a particle layer
Dalziel, Stuart
Resuspension onset and crater erosion by a vortex ring interacting with a particle layer N. Bethke://pof.aip.org/features/most_downloaded Information for Authors: http://pof.aip.org/authors #12;PHYSICS OF FLUIDS 24, 063301 (2012) Resuspension onset layer. The flow dynamics during the onset of particle resuspension are analysed using particle image
Sediment resuspension and erosion by vortex rings R. J. Munro,1,a
Dalziel, Stuart
Sediment resuspension and erosion by vortex rings R. J. Munro,1,a N. Bethke,2 and S. B. Dalziel2 1; accepted 26 January 2009; published online 8 April 2009 Particle resuspension and erosion induced-ring propagation speed. The critical conditions for resuspension whereby particles are only just resuspended were
Fluid Dynamics Research 33 (2003) 333356 Leapfrogging vortex rings: Hamiltonian structure, geometric
Shashikanth, Banavara N.
2003-01-01T23:59:59.000Z
Fluid Dynamics Research 33 (2003) 333356 Leapfrogging vortex rings: Hamiltonian structure that if the rings are modeled as coaxial circular ÿlaments, their dynamics and Hamil- tonian structure is derivable of Mechanical Engineering, New Mexico State University, Las Cruces, NM 88003, USA b Control and Dynamical
Vortex-peak interaction and lattice shape in rotating two-component Bose-Einstein condensates
Wei, Jun-cheng
Vortex-peak interaction and lattice shape in rotating two-component Bose-Einstein condensates: November 28, 2011) When a two component Bose-Einstein condensate is placed into rotation, a lattice component condensate is set into rotation, topological defects of both order parameters are created, which
Formation and Decay of Vortex Lattices in Bose-Einstein Condensates at Finite Temperatures
Formation and Decay of Vortex Lattices in Bose-Einstein Condensates at Finite Temperatures Gaseous Bose-Einstein condensates (BEC) are a testbed for many-body theory. Recently, rotating condensates was observed non-destructively by monitoring the centrifugal distortions of the rotating condensate
ccsd00003161, Vortex patterns in a fast rotating Bose-Einstein condensate
. Furthermore we restrict our analysis to the case of a two-dimensional gas in the xy plane, assumingccsdÂ00003161, version 1 Â 26 Oct 2004 Vortex patterns in a fast rotating Bose-Einstein condensate, France (Dated: October 26, 2004) For a fast rotating condensate in a harmonic trap, we investigate
Spacetime Defects von K\\'arm\\'an vortex street like configurations
Letelier, P S
2001-01-01T23:59:59.000Z
A special arrangement of spinning strings with dislocations similar to a von K\\'arm\\'an vortex street is studied. We numerically solve the geodesic equations for the special case of a test particle moving along twoinfinite rows of pure dislocations and also discuss the case of pure spinning defects.
Theory of vortex crystal formation in two-dimensional turbulence* Dezhe Z. Jin
California at San Diego, University of
Theory of vortex crystal formation in two-dimensional turbulence* Dezhe Z. Jin and Daniel H. E are symmetric arrays of strong vortices within a background of weaker vorticity. This paper presents a theory, a theory is advanced that allows us to predict from the initial conditions the approximate number
Thermal Stabilization Blend Plan
RISENMAY, H.R.
2000-05-02T23:59:59.000Z
This Blend Plan documents the feed material items that are stored in 2736-2 vaults, the 2736-ZB 638 cage, the 192C vault, and the 225 vault that will be processed through the thermal stabilization furnaces. The purpose of thermal stabilization is to heat the material to 1000 degrees Celsius to drive off all water and leave the plutonium and/or uranium as oxides. The stabilized material will be sampled to determine the Loss On Ignition (LOI) or percent water. The stabilized material must meet water content or LOI of less than 0.5% to be acceptable for storage under DOE-STD-3013-99 specifications. Out of specification material will be recycled through the furnaces until the water or LOI limits are met.
Schlegel, Fabrice
Using high-resolution 3-D vortex simulations, this study seeks a mechanistic understanding of vorticity dynamics in transverse jets at a finite Reynolds number. A full no-slip boundary condition, rigorously formulated in ...
Miyamoto, K., E-mail: k-miyamoto@faculty.chiba-u.jp [Graduate School of Advanced Integration Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); Suizu, K.; Akiba, T. [Department of Electrical, Electronics and Computer Engineering, Chiba Institute of Technology, 2-17-1 Tsudanuma, Narashino, Chiba 275-0016 (Japan); Omatsu, T. [Graduate School of Advanced Integration Science, Chiba University, 1-33 Yayoi-cho, Inage-ku, Chiba 263-8522 (Japan); CREST Japan Science and Technology Agency, Sanbancho, Chiyoda-ku, Tokyo 102-0075 (Japan)
2014-06-30T23:59:59.000Z
A terahertz (THz) spiral phase plate with high transmission (>90% after Fresnel correction) and low dispersion has been developed based on the Tsurupica olefin polymer. Direct observations of the topological charge (both magnitude and sign) of a THz vortex beam are performed by using a THz camera with tilted lens focusing and radial defect introduction. The vortex outputs with a topological charge of ±1 (or ±2) are obtained at a frequency of 2 (or 4) THz.
Hibbs, R.; Chen, Y.; Nikitopoulos, D. [Louisiana State Univ., Baton Rouge, LA (United States)] [and others
1995-10-01T23:59:59.000Z
The effect of vortex generators on the mass (heat) transfer from the ribbed passage of a two pass turbine blade coolant channel is investigated with the intent of optimizing the vortex generator geometry so that significant enhancements in mass/heat transfer can be achieved. In the experimental configuration considered, ribs are mounted on two opposite walls; all four walls along each pass are active and have mass transfer from their surfaces but the ribs are non-participating. Mass transfer measurements, in the form of Sherwood number ratios, are made along the centerline and in selected inter-rib modules. Results are presented for Reynolds number in the range of 5,000 to 40,000, pitch to rib height ratios of 10.5 and 21, and vortex generator-rib spacing to rib height ratios of 0.55, and 1.5. Centerline and spanwise averaged Sherwood number ratios are presented along with contours of the Sherwood number ratios. Results indicate that the vortex generators induce substantial increases in the local mass transfer rates, particularly along the side walls, and modest increases in the average mass transfer rates. The vortex generators have the effect of making the inter-rib profiles along the ribbed walls more uniform. Along the side walls, horse-shoe vortices that characterize the vortex generator wake are associated with significant mass transfer enhancements. The wake effects and the levels of enhancement decrease somewhat with increasing Reynolds number and decreasing pitch.
Hibbs, R.; Acharya, S.; Chen, Y. [Louisiana State Univ., Baton Rouge, LA (United States)] [and others
1995-12-31T23:59:59.000Z
The effect of vortex generators on the mass (heat) transfer from the ribbed passage of a two pass turbine blade coolant channel is investigated with the intent of optimizing the vortex generator geometry so that significant enhancements in mass/heat transfer can be achieved. In the experimental configuration considered, ribs are mounted on two opposite walls; all four walls along each pass are active and have mass transfer from their surfaces but the ribs are non-participating. Mass transfer measurements, in the form of Sherwood number ratios, are made along the centerline and in selected inter-rib modules. Results are presented for Reynolds number in the range of 5,000 to 40,000, pitch to rib height ratios of 10.5 and 21, and vortex generator-rib spacing to rib height ratios of 0.55, and 1.5. Centerline and spanwise averaged Sherwood number ratios are presented along with contours of the Sherwood number ratios. Results indicate that the vortex generators induce substantial increases in the local mass transfer rates, particularly along the side walls, and modest increases in the average mass transfer rates. The vortex generators have the effect of making the inter-rib profiles along the ribbed walls more uniform. Along the side walls, horse-shoe vortices that characterize the vortex generator wake are associated with significant mass transfer enhancements. The wake effects and the levels of enhancement decrease somewhat with increasing Reynolds number and decreasing pitch.
Hibbs, R.G.; Acharya, S.; Chen, Y.; Nikitopoulos, D.E.; Myrum, T.A. [Louisiana State Univ., Baton Rouge, LA (United States). Mechanical Engineering Dept.
1998-07-01T23:59:59.000Z
The effect of vortex generators on the mass (heat) transfer from the ribbed passage of a two-pass turbine blade coolant channel is investigated with the intent of optimizing the vortex generator geometry so that significant enhancements in mass/heat transfer can be achieved. In the experimental configuration considered, ribs are mounted on two opposite walls; all four walls along each pass are active and have mass transfer from their surfaces but the ribs are nonparticipating. Mass transfer measurements, in the form of Sherwood number ratios, are made along the centerline and in selected interrib modules. Results are presented for Reynolds number in the range of 5000 to 40,000 pitch to rib height ratios of 10.5 and 21, and vortex generator-rib spacing to rib height ratios of 0.55 and 1.5. Centerline and spanwise-averaged Sherwood number ratios are presented along with contours of the Sherwood number ratios. Results indicate that the vortex generators lead to substantial increases in the local mass transfer rates, particularly along the side walls, and modest increases in the average mass transfer rates. The vortex generators have the effect of making the interrib profiles along the ribbed walls more uniform. Along the side walls, vortices that characterize the vortex generator wake are associated with significant mass transfer enhancements. The wake effects and the levels of enhancement decrease somewhat with increasing Reynolds number and decreasing pitch.
Van Gorder, Robert A., E-mail: rav@knights.ucf.edu [Department of Mathematics, University of Central Florida, Orlando, Florida 32816-1364 (United States)
2014-06-15T23:59:59.000Z
In his study of superfluid turbulence in the low-temperature limit, Svistunov [“Superfluid turbulence in the low-temperature limit,” Phys. Rev. B 52, 3647 (1995)] derived a Hamiltonian equation for the self-induced motion of a vortex filament. Under the local induction approximation (LIA), the Svistunov formulation is equivalent to a nonlinear dispersive partial differential equation. In this paper, we consider a family of rotating vortex filament solutions for the LIA reduction of the Svistunov formulation, which we refer to as the 2D LIA (since it permits a potential formulation in terms of two of the three Cartesian coordinates). This class of solutions holds the well-known Hasimoto-type planar vortex filament [H. Hasimoto, “Motion of a vortex filament and its relation to elastica,” J. Phys. Soc. Jpn. 31, 293 (1971)] as one reduction and helical solutions as another. More generally, we obtain solutions which are periodic in the space variable. A systematic analytical study of the behavior of such solutions is carried out. In the case where vortex filaments have small deviations from the axis of rotation, closed analytical forms of the filament solutions are given. A variety of numerical simulations are provided to demonstrate the wide range of rotating filament behaviors possible. Doing so, we are able to determine a number of vortex filament structures not previously studied. We find that the solution structure progresses from planar to helical, and then to more intricate and complex filament structures, possibly indicating the onset of superfluid turbulence.
Dinwoodie, Thomas L. (Piedmont, CA)
2002-12-17T23:59:59.000Z
A stabilized PV system comprises an array of photovoltaic (PV) assemblies mounted to a support surface. Each PV assembly comprises a PV module and a support assembly securing the PV module to a position overlying the support surface. The array of modules is circumscribed by a continuous, belt-like perimeter assembly. Cross strapping, extending above, below or through the array, or some combination of above, below and through the array, secures a first position along the perimeter assembly to at least a second position along the perimeter assembly thereby stabilizing the array against wind uplift forces. The first and second positions may be on opposite sides on the array.
Dussaux, A.; Rache Salles, B.; Jenkins, A. S.; Bortolotti, P.; Grollier, J.; Cros, V.; Fert, A. [Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Ave. A. Fresnel, 91767 Palaiseau (France); Grimaldi, E., E-mail: eva.grimaldi@thalesgroup.com [Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Ave. A. Fresnel, 91767 Palaiseau (France); CNES, 1 Avenue Edouard Belin, 31400 Toulouse (France); Khvalkovskiy, A. V. [Unité Mixte de Physique CNRS/Thales and Université Paris Sud 11, 1 Ave. A. Fresnel, 91767 Palaiseau (France); A.M. Prokhorov General Physics Institute of RAS, Vavilova Str. 38, 119991 Moscow (Russian Federation); Kubota, H.; Fukushima, A.; Yakushiji, K.; Yuasa, S. [National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba (Japan)
2014-07-14T23:59:59.000Z
We investigate the microwave response of a spin transfer vortex based oscillator in a magnetic tunnel junction with an in-plane reference layer combined with a spin valve with an out-of-plane magnetization spin polarizing layer. The main advantage of this perpendicular spin polarizer is to induce a large spin transfer force even at zero magnetic field, thus leading to a record emitted power (up to 0.6??W) associated to a very narrow spectral linewidth of a few hundreds of kHz. The characteristics of this hybrid vortex based spin transfer nano-oscillator obtained at zero field and room temperature are of great importance for applications based on rf spintronic devices as integrated and tunable microwave source and/or microwave detector.
Von K\\'arm\\'an Vortex Street within an Impacting Drop
Thoraval, Marie-Jean; Etoh, Takeharu Goji; Popinet, Stephane; Ray, Pascal; Josserand, Christophe; Zaleski, Stephane; Thoroddsen, Sigurdur
2012-01-01T23:59:59.000Z
The splashing of a drop impacting onto a liquid pool produces a range of different sized micro-droplets. At high impact velocities, the most significant source of these droplets is a thin liquid jet emerging at the start of the impact from the neck that connects the drop to the pool. We use ultra-high-speed video imaging in combination with high-resolution numerical simulations to show how the ejecta gives way to irregular splashing. At higher Reynolds number, its base becomes unstable, shedding vortex rings into the liquid from the free surface in an axisymmetric von K\\'arm\\'an vortex street, thus breaking the ejecta sheet as it forms.
Analytical Tendex and Vortex Fields for Perturbative Black Hole Initial Data
Kenneth A. Dennison; Thomas W. Baumgarte
2012-07-10T23:59:59.000Z
Tendex and vortex fields, defined by the eigenvectors and eigenvalues of the electric and magnetic parts of the Weyl curvature tensor, form the basis of a recently developed approach to visualizing spacetime curvature. In particular, this method has been proposed as a tool for interpreting results from numerical binary black hole simulations, providing a deeper insight into the physical processes governing the merger of black holes and the emission of gravitational radiation. Here we apply this approach to approximate but analytical initial data for both single boosted and binary black holes. These perturbative data become exact in the limit of small boost or large binary separation. We hope that these calculations will provide additional insight into the properties of tendex and vortex fields, and will form a useful test for future numerical calculations.
Tripolar vortex formation in dense quantum plasma with ion-temperature-gradients
Qamar, Anisa; Ata-ur-Rahman [Institute of Physics and Electronics, University of Peshawar, Khyber Pakhtoon Khwa 25000 (Pakistan); National Center for Physics Shahdrah Valley Road, Islamabad 44000 (Pakistan); Mirza, Arshad M. [Theoretical Plasma Physics Group, Physics Department, Quaid-i-Azam University, Islamabad 45320 (Pakistan)
2012-05-15T23:59:59.000Z
We have derived system of nonlinear equations governing the dynamics of low-frequency electrostatic toroidal ion-temperature-gradient mode for dense quantum magnetoplasma. For some specific profiles of the equilibrium density, temperature, and ion velocity gradients, the nonlinear equations admit a stationary solution in the form of a tripolar vortex. These results are relevant to understand nonlinear structure formation in dense quantum plasmas in the presence of equilibrium ion-temperature and density gradients.
Hierarchical Colloidal Vortex Rings in a Constant Electric Field Yilong Han and David G. Grier
Grier, David
often, the dense ring of 30 25 20 15 10 5 0 15 (b) (c) (d) (e) packed close- core vortex ring (d) (e) (b) (c) (a) (f) corona t [sec] Rg (t) [µm] +V h H 20 µm glass slide cluster electrode R g 20 µm FIG. 1 is surrounded by a di#11;use circulating corona that extends outward for tens of micrometers. Although
Under consideration for publication in J. Fluid Mech. 1 Three-dimensional vortex dynamics in
Pawlak, Geno
, the boundary layer can become centrifugally unstable (Honji 1981), leading to well-developed G¨ortler vortices dissipation and boundary layer dynamics. It is widely accepted that vortex shedding is a dominant pr in oscillatory flow separation M I G U E L C A N A L S AND G E N O P A W L A K Department of Ocean and Resources
Vortex free energy and deconfinement in center-blind discretizations of Yang-Mills theories
Burgio, G; Kerler, W; Müller-Preussker, M
2006-01-01T23:59:59.000Z
Maximal 't Hooft loops are studied in SO(3) lattice gauge theory at finite temperature T. Tunneling barriers among twist sectors causing loss of ergodicity for local update algorithms are overcome through parallel tempering, enabling us to measure the vortex free energy F and to identify a deconfinement transition at some $\\beta_A^{crit}$. The behavior of F below $\\beta_A^{crit}$ shows however striking differences with what is expected from discretizations in the fundamental representation.
Landweber, Laura
and complexity of a commu- nity of interacting plants and animals, following the food web as a clue. Contrary in power. Stability and Complexity in Model Ecosystems played a key role in introducing nonlinear thinking, and current threats to biodiversity have made questions about the role of ecosystem complexity
Stabilized chromium oxide film
Garwin, Edward L. (Los Altos, CA); Nyaiesh, Ali R. (Palo Alto, CA)
1988-01-01T23:59:59.000Z
Stabilized air-oxidized chromium films deposited on high-power klystron ceramic windows and sleeves having a thickness between 20 and 150.ANG. are useful in lowering secondary electron emission yield and in avoiding multipactoring and window failure due to overheating. The ceramic substrate for the film is chosen from alumina, sapphire or beryllium oxide.
Stabilized chromium oxide film
Nyaiesh, A.R.; Garwin, E.L.
1986-08-04T23:59:59.000Z
Stabilized air-oxidized chromium films deposited on high-power klystron ceramic windows and sleeves having a thickness between 20 and 150A are useful in lowering secondary electron emission yield and in avoiding multipactoring and window failure due to overheating. The ceramic substrate for the film is chosen from alumina, sapphire or beryllium oxide.
Tetraphenylborate Solids Stability Tests
Walker, D.D. [Westinghouse Savannah River Company, AIKEN, SC (United States); Edwards, T.B.
1997-12-19T23:59:59.000Z
Tetraphenylborate solids provide a potentially large source of benzene in the slurries produced in the In-Tank Precipitation process. The stability of the solids is an important consideration in the safety analysis of the process and we desire an understanding of the factors that influence the rate of conversion of the solids to benzene.
Llordes, Anna [ICMAB, Barcelona, Spain; Palau, A. [ICMAB, Barcelona, Spain; Gazquez, J. [Oak Ridge National Laboratory (ORNL); Coll, M. [ICMAB, Barcelona, Spain; Vlad, R. [ICMAB, Barcelona, Spain; Pomar, A. [ICMAB, Barcelona, Spain; Arbiol, Jordi [ICMAB, Barcelona, Spain; Guzman, Roger [ICMAB, Barcelona, Spain; Ye, S. [ICMAB, Barcelona, Spain; Rouco, V [ICMAB, Barcelona, Spain; Sandiumenge, Felip [ICMAB, Barcelona, Spain; Ricart, Susagna [ICMAB, Barcelona, Spain; Puig, Teresa [ICMAB, Barcelona, Spain; Varela del Arco, Maria [ORNL; Chataigner, D. [CRISMAT, Caen, France; Vanacken, J. [INPAC-Institute for Nanoscale Physics and Chemistry, Leuven, Belgium; Gutierrez, J. [INPAC-Institute for Nanoscale Physics and Chemistry, Leuven, Belgium; Moschalkov, V. [INPAC-Institute for Nanoscale Physics and Chemistry, Leuven, Belgium; Deutscher, G. [Tel Aviv University; Magen Dominguez, Cesar [ORNL; Obradors, Xavier [ICMAB, Barcelona, Spain
2012-01-01T23:59:59.000Z
Boosting large-scale superconductor applications require nanostructured conductors with artificial pinning centres immobilizing quantized vortices at high temperature and magnetic fields. Here we demonstrate a highly effective mechanism of artificial pinning centers in solution-derived high-temperature superconductor nanocomposites through generation of nanostrained regions where Cooper pair formation is suppressed. The nanostrained regions identified from transmission electron microscopy devise a very high concentration of partial dislocations associated with intergrowths generated between the randomly oriented nanodots and the epitaxial YBa{sub 2}Cu{sub 3}O{sub 7} matrix. Consequently, an outstanding vortex-pinning enhancement correlated to the nanostrain is demonstrated for four types of randomly oriented nanodot, and a unique evolution towards an isotropic vortex-pinning behaviour, even in the effective anisotropy, is achieved as the nanostrain turns isotropic. We suggest a new vortex-pinning mechanism based on the bond-contraction pairing model, where pair formation is quenched under tensile strain, forming new and effective core-pinning regions.
Stability of Coupling Algorithms
Akkasale, Abhineeth
2012-07-16T23:59:59.000Z
of Committee, K. B. Nakshatrala Committee Members, Steve Suh J. N. Reddy Head of Department, Dennis O?Neal May 2011 Major Subject: Mechanical Engineering iii ABSTRACT Stability of Coupling Algorithms. (May 2011) Abhineeth Akkasale, B.E., Bangalore... step. iv To Amma and Anna v ACKNOWLEDGMENTS First and foremost, I thank Dr. Kalyana B. Nakshatrala for being an incredible advisor and for his time and patience in constantly guiding me through my research. I am indebted to him for his guidance...
Simplex stability Dhruv Mubayi
Mubayi, Dhruv
Simplex stability Dhruv Mubayi Reshma Ramadurai November 5, 2008 Abstract A d-simplex that contains no d-simplex. We prove that if |G| (1 - o(1)) n-1 k-1 , then there is a vertex x of G such that the Ai's form a d-simplex, and A contains an element of j=iAj for each i. This generalizes, in asymptotic
Codeword Stabilized Quantum Codes
Andrew Cross; Graeme Smith; John A. Smolin; Bei Zeng
2007-09-27T23:59:59.000Z
We present a unifying approach to quantum error correcting code design that encompasses additive (stabilizer) codes, as well as all known examples of nonadditive codes with good parameters. We use this framework to generate new codes with superior parameters to any previously known. In particular, we find ((10,18,3)) and ((10,20,3)) codes. We also show how to construct encoding circuits for all codes within our framework.
Evgeny A. Ryzhov; K. V. Koshel
2012-09-27T23:59:59.000Z
In the frame of a three-layer quasi-geostrophic analytical model of a $f$-plane geophysical flow, Lagrangian advection being induced by the interaction of a monopole vortex with an isolated topographic feature is addressed. Two different cases when the monopole locates either within the upper or the middle layer are of our interest. In the bottom layer, there is a delta function topographic feature, which generates a closed recirculation region in its vicinity due to the background flow. This recirculation region extends to the middle and upper layers, and it plays the role of a topographic vortex. The interaction between the monopole and the topographic vortex causes complex, including chaotic, advection of fluid particles. We show that the model's parameters, namely, the monopole and topographic vortices' strengths and initial positions, the layers' depths and densities are responsible for the diverse advection patterns. While the patterns are rather complicated, however, one can single out two major processes, which mostly govern fluid particle advection. The first one is the variation in time of the system's phase space structure, so that within the closed region of the topographic vortex, there appear periodically unclosed particle pathways by which the particles leave the topographic vortex. The second one is chaotic advection that arises from the nonstationarity of the monopole-topography interaction.
Otani, Yoshichika
Controlled propagation of locally excited vortex dynamics in linear nanomagnet arrays This article. Here, we present a controlled propagation of locally excited magnetic vortex dynamics through a linear. Phys. D: Appl. Phys. 43 (2010) 335001 (7pp) doi:10.1088/0022-3727/43/33/335001 Controlled propagation
Protas, Bartosz
. Following a comprehensive review of earlier approaches, we discuss how methods of modern control and optimization theory can be employed to solve control problems for vortex system. In addition, we also address vortex systems, in the second part of the paper we also introduce a novel approach to the control
Claxton, Gerald L. (Fresno, CA)
1999-01-01T23:59:59.000Z
A stabilizing suspension system is provided for vehicles carrying telescopic booms or aerial work platforms having a fixed axle and a oscillating axle. Hydraulic cylinders are connected to each end of the oscillating axle, each cylinder being capable of extending and retracting. An off level sensor senses the angle of tilt of the chassis in both left and right directions and, when a predetermined threshold of tilt has been detected, the hydraulic cylinder on the downhill side of the chassis is locked against retracting, but is free to move in the downhill direction to allow the downhill wheel to remain in contact with the ground.
Ultrasound scattering and the study of vortex correlations in disordered flows
Denis Boyer; Fernando Lund
1999-12-14T23:59:59.000Z
In an idealized way, some turbulent flows can be pictured by assemblies of many vortices characterized by a set of particle distribution functions. Ultrasound provide an useful, nonintrusive, tool to study the spatial structure of vorticity in flows. This is analogous to the use of elastic neutron scattering to determine liquid structure. We express the dispersion relation, as well as the scattering cross section, of sound waves propagating in a ``liquid'' of identical vortices as a function of vortex pair correlation functions. In two dimensions, formal analogies with ionic liquids are pointed out.
Geometry and scaling of tangled vortex lines in three-dimensional random wave fields
Alexander J. Taylor; Mark R. Dennis
2015-01-20T23:59:59.000Z
The short- and long-scale behaviour of tangled wave vortices (nodal lines) in random three-dimensional wave fields is studied via computer experiment. The zero lines are tracked in numerical simulations of periodic superpositions of three-dimensional complex plane waves. The probability distribution of local geometric quantities such as curvature and torsion are compared to previous analytical and new Monte Carlo results from the isotropic Gaussian random wave model. We further examine the scaling and self-similarity of tangled wave vortex lines individually and in the bulk, drawing comparisons with other physical systems of tangled filaments.
Extraordinary optical transmission and vortex excitation by periodic arrays of Fresnel zone plates
Roszkiewicz, A
2013-01-01T23:59:59.000Z
Extraordinary optical transmission and good focusing properties of a two-dimensional scattering structure is presented. The structure is made of Fresnel zone plates periodically arranged along two orthogonal directions. Each plate consists of two ring-shaped waveguides supporting modes that match the symmetry of a circularly polarized incident plane wave. High field concentration at the focal plane is obtained with short transverse and long longitudinal foci diameters. Optical vortex excitation in a paraxial region of the transmitted field is also observed and analysed in terms of cross-polarisation coupling. The structure presented may appear useful in visualization, trapping and precise manipulations of nanoparticles.
Critical current density and mechanism of vortex pinning in KxFe2-ySe? doped with S
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Lei, Hechang; Petrovic, C.
2011-08-01T23:59:59.000Z
We report the critical current density Jc in KxFe2-ySe2-zSz crystals. The Jc can be enhanced significantly with optimal S doping (z=0.99). For K0.70(7)Fe1.55(7)Se1.01(2)S0.99(2), the weak fishtail effect is found for H II c. The normalized vortex pinning forces follow the scaling law with a maximum position at 0.41 of the reduced magnetic field. These results demonstrate that the small size normal point defects dominate the vortex pinning mechanism.
MAP, MAC, and Vortex-rings Configurations in the Weinberg-Salam Model
Rosy Teh; Ban-Loong Ng; Khai-Ming Wong
2015-03-20T23:59:59.000Z
We report on the presence of new axially symmetric monopoles, antimonopoles and vortex-rings solutions of the SU(2)$\\times$U(1) Weinberg-Salam model of electromagnetic and weak interactions. When the $\\phi$-winding number $n=1$, and 2, the configurations are monopole-antimonopole pair (MAP) and monopole-antimonopole chain (MAC) with poles of alternating sign magnetic charge arranged along the $z$-axis. Vortex-rings start to appear from the MAP and MAC configurations when the winding number $n=3$. The MAP configurations possess zero net magnetic charge whereas the MAC configurations possess net magnetic charge of $4\\pi n/e$. In the MAP configurations, the monopole-antimonopole pair is bounded by the ${\\cal Z}^0$ field flux string and there is an electromagnetic current loop encircling it. The monopole and antimonopole possess magnetic charges $\\pm\\frac{4\\pi n}{e}\\sin^2\\theta_W$ respectively. In the MAC configurations there is no string connecting the monopole and the adjacent antimonopole and they possess magnetic charges $\\pm\\frac{4\\pi n}{e}$ respectively. The MAC configurations possess infinite total energy and zero magnetic dipole moment whereas the MAP configurations which are actually sphalerons possess finite total energy and magnetic dipole moment. The configurations were investigated for varying values of Higgs self-coupling constant $0\\leq \\lambda\\leq 40$ at Weinberg angle $\\theta_W=\\frac{\\pi}{4}$.
Filamentary structures in dense plasma focus: Current filaments or vortex filaments?
Soto, Leopoldo, E-mail: lsoto@cchen.cl; Pavez, Cristian; Moreno, José [Comisión Chilena de Energía Nuclear, CCHEN, Casilla 188-D, Santiago (Chile); Center for Research and Applications in Plasma Physics and Pulsed Power, P4, Departamento de Ciencias Físicas, Facultad de Ciencias Exactas, Universidad Andrés Bello, República 220, Santiago (Chile); Castillo, Fermin [Universidad Nacional Autónoma de México, Cuernavaca, México (Mexico); Veloso, Felipe [Instituto de Física, Pontificia Universidad Católica de Chile, 7820436 Santiago (Chile); Auluck, S. K. H. [Bhabha Atomic Research Center, Mumbai 400 085 (India)
2014-07-15T23:59:59.000Z
Recent observations of an azimuthally distributed array of sub-millimeter size sources of fusion protons and correlation between extreme ultraviolet (XUV) images of filaments with neutron yield in PF-1000 plasma focus have re-kindled interest in their significance. These filaments have been described variously in literature as current filaments and vortex filaments, with very little experimental evidence in support of either nomenclature. This paper provides, for the first time, experimental observations of filaments on a table-top plasma focus device using three techniques: framing photography of visible self-luminosity from the plasma, schlieren photography, and interferometry. Quantitative evaluation of density profile of filaments from interferometry reveals that their radius closely agrees with the collision-less ion skin depth. This is a signature of relaxed state of a Hall fluid, which has significant mass flow with equipartition between kinetic and magnetic energy, supporting the “vortex filament” description. This interpretation is consistent with empirical evidence of an efficient energy concentration mechanism inferred from nuclear reaction yields.
Direct femtosecond laser ablation of copper with an optical vortex beam
Anoop, K. K.; Rubano, A.; Marrucci, L.; Bruzzese, R.; Amoruso, S., E-mail: amoruso@na.infn.it [Dipartimento di Fisica, Università di Napoli Federico II, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); CNR-SPIN, UOS Napoli, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy); Fittipaldi, R.; Vecchione, A. [CNR-SPIN, UOS Salerno, Via Giovanni Paolo II 132, I-84084 Fisciano (Italy); Wang, X.; Paparo, D. [CNR-SPIN, UOS Napoli, Complesso Universitario di Monte S. Angelo, Via Cintia, I-80126 Napoli (Italy)
2014-09-21T23:59:59.000Z
Laser surface structuring of copper is induced by laser ablation with a femtosecond optical vortex beam generated via spin-to-orbital conversion of the angular momentum of light by using a q-plate. The variation of the produced surface structures is studied as a function of the number of pulses, N, and laser fluence, F. After the first laser pulse (N?=?1), the irradiated surface presents an annular region characterized by a corrugated morphology made by a rather complex network of nanometer-scale ridges, wrinkles, pores, and cavities. Increasing the number of pulses (2??1000) and a deep crater is formed. The nanostructure variation with the laser fluence, F, also evidences an interesting dependence, with a coarsening of the structure morphology as F increases. Our experimental findings demonstrate that direct femtosecond laser ablation with optical vortex beams produces interesting patterns not achievable by the more standard beams with a Gaussian intensity profile. They also suggest that appropriate tuning of the experimental conditions (F, N) can allow generating micro- and/or nano-structured surface for any specific application.
Vortex and structural dynamics of a flexible cylinder in cross-flow
Shang, Jessica K., E-mail: jshang@princeton.edu; Stone, Howard A. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States); Smits, Alexander J. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, New Jersey 08544 (United States); Monash University, VIC 3800 (Australia)
2014-05-15T23:59:59.000Z
A low-density, flexible cantilevered cylinder was permitted to vibrate freely under the influence of vortex shedding in the laminar flow regime. We find that the vortex-induced vibrations (VIV) of a flexible cantilever depart from those of a flexible cylinder that is fixed at both ends. In particular, we find discontinuous regions of VIV behavior – here called states – as a function of the reduced velocity U{sup *}. These states are demarcated by discrete changes in the dominant eigenmodes of the structural response as the cylinder vibrates in progressively higher structural modes with increasing U{sup *}. The contribution of structural modes can be identified readily by a modal projection of the cylinder oscillation onto known cantilever beam modes. Oscillation frequencies do not monotonically increase with U{sup *}. The wake response between different states is also found to have distinct characteristics; of particular note is the occurrence of a P+S wake over one of these regions, which is associated with a high-amplitude vibration of the cylinder that is due to the constructive interference of contributing eigenmodes.
IMPROVED ROOF STABILIZATION TECHNOLOGIES
M.A. Ebadian, Ph.D.
1999-01-01T23:59:59.000Z
Many U.S. Department of Energy (DOE) remediation sites have performed roof repair and roof replacement to stabilize facilities prior to performing deactivation and decommissioning (D&D) activities. This project will review the decision criteria used by these DOE sites, along with the type of repair system used for each different roof type. Based on this information, along with that compiled from roofing experts, a decision-making tool will be generated to aid in selecting the proper roof repair systems. Where appropriate, innovative technologies will be reviewed and applied to the decision-making tool to determine their applicability. Based on the results, applied research and development will be conducted to develop a method to repair these existing roofing systems, while providing protection for the D and D worker in a cost-efficient manner.
Laser controlled flame stabilization
Early, James W. (Los Alamos, NM); Thomas, Matthew E. (Huntsville, AL)
2001-01-01T23:59:59.000Z
A method and apparatus is provided for initiating and stabilizing fuel combustion in applications such as gas turbine electrical power generating engines and jet turbine engines where it is desired to burn lean fuel/air mixtures which produce lower amounts of NO.sub.x. A laser induced spark is propagated at a distance from the fuel nozzle with the laser ignitor being remotely located from the high temperature environment of the combustion chamber. A laser initiating spark generated by focusing high peak power laser light to a sufficiently tight laser spot within the fuel to cause the ionization of air and fuel into a plasma is unobtrusive to the flow dynamics of the combustion chamber of a fuel injector, thereby facilitating whatever advantage can be taken of flow dynamics in the design of the fuel injector.
Dabiri, John O.
Graduate Aeronautical Laboratories and Bioengineering, California Institute of Technology, Pasadena velocity fixed. It turned out that the pinch-off was always observed to occur at a stroke ratio L time scale for the pinch-off process formation number was tested by generating vortex rings
http://rcc.its.psu.edu/hpc Optimization of a Vortex Finder in a Cyclone Separator using
Bjørnstad, Ottar Nordal
http://rcc.its.psu.edu/hpc Optimization of a Vortex Finder in a Cyclone Separator using Particle of fluidized bed power plants is the cyclone separator. The cyclone separator is used to remove smaller particles, those not large enough for heat transfer, and retain large particles. The cyclone separator
Zero-energy states bound to a magnetic pi-flux vortex in a two-dimensional topological insulator
Andrej Mesaros; Robert-Jan Slager; Jan Zaanen; Vladimir Juricic
2012-10-22T23:59:59.000Z
We show that the existence of a pair of zero-energy modes bound to a vortex carrying a pi-flux is a generic feature of the topologically non-trivial phase of the M-B model, which was introduced to describe the topological band insulator in HgTe quantum wells. We explicitly find the form of the zero-energy states of the corresponding Dirac equation, which contains a novel momentum-dependent mass term and describes a generic topological transition in a band insulator. The obtained modes are exponentially localized in the vortex-core, with the dependence of characteristic length on the parameters of the model matching the dependence extracted from a lattice version of the model. We consider in full generality the short-distance regularization of the vector potential of the vortex, and show that a particular choice yields the modes localized and simultaneously regular at the origin. Finally, we also discuss a realization of two-dimensional spin-charge separation through the vortex zero-modes.
Metlushko, Vitali
Direct observation of superconducting vortex clusters pinned by a periodic array of magnetic dots in ferromagnetic/superconducting hybrid structures T. Shapoval,1,* V. Metlushko,2 M. Wolf,1 B. Holzapfel,1 V. Neu,1, Illinois 60612, USA Received 13 November 2009; published 11 March 2010 Strong pinning of superconducting
Boyer, Edmond
-Einstein condensates Ionut Danaila,a,b , FrÂ´edÂ´eric Hechta,b aUPMC Univ Paris 06, UMR 7598, Laboratoire Jacques Abstract Numerical computations of stationary states of fast-rotating Bose-Einstein condensates require-Einstein condensate, vortex, Sobolev gradient, descent method. 1. Introduction Recent research efforts in the field
Recanati, Catherine
ÂEinstein condensates Ionut Danaila #,a,b , Frâ??edâ??eric Hecht a,b a UPMC Univ Paris 06, UMR 7598, Laboratoire Jacques Abstract Numerical computations of stationary states of fastÂrotating BoseÂEinstein condensates requireÂEinstein condensate, vortex, Sobolev gradient, descent method. 1. Introduction Recent research e#orts in the field
ccsd-00003161,version1-26Oct2004 Vortex patterns in a fast rotating Bose-Einstein condensate
of the rotating gas increases and tends to infinity, and the number of vortices in the condensate diverges [5, 6. Furthermore we restrict our analysis to the case of a two- dimensional gas in the xy plane, assumingccsd-00003161,version1-26Oct2004 Vortex patterns in a fast rotating Bose-Einstein condensate
Godoy-Diana, Ramiro; Aider, Jean-Luc; Wesfreid, José Eduardo
2008-01-01T23:59:59.000Z
The vortex streets produced by a flapping foil of span-to-chord aspect ratio of 4:1 are studied in a hydrodynamic tunnel experiment. In particular, the mechanisms giving rise to the symmetry breaking of the reverse B\\'enard-von K\\'arm\\'an vortex street that characterizes fish-like swimming and forward flapping flight are examined. Two-dimensional particle image velocimetry measurements in the mid-plane perpendicular to the span axis of the foil are used to characterize the different flow regimes. The deflection angle of the mean jet flow with respect to the horizontal observed in the average velocity field is used as a measure of the asymmetry of the vortex street. Time series of the vorticity field are used to calculate the advection velocity of the vortices with respect to the free-stream, defined as the phase velocity $U_{phase}$, as well as the circulation $\\Gamma$ of each vortex and the spacing $\\xi$ between consecutive vortices in the near wake. The observation that the symmetry breaking results from th...
First-Order Transition in the Magnetic Vortex Matter in Superconducting MgB2 Tuned by Disorder
Boyer, Edmond
First-Order Transition in the Magnetic Vortex Matter in Superconducting MgB2 Tuned by Disorder T such as Wigner crystals, charge density waves, magnetic bubble arrays, or vortices in type-II superconductors posi- tional correlations. Vortices in superconductors rapidly became the system of choice
Stabilized radio-frequency quadrupole
Lancaster, H.D.; Fugitt, J.A.; Howard, D.R.
1982-09-29T23:59:59.000Z
A long-vane stabilized radio frequency resonator for accelerating charged particles and including means defining a radio frequency resonator cavity, a plurality of long vanes mounted in the defining means for dividing the cavity into sections, and means interconnecting opposing ones of the plurality of vanes for stabilizing the resonator.
Project Management Plan Solution Stabilization
SATO, P.K.
1999-08-31T23:59:59.000Z
This plan presents the overall objectives, description, justification and planning for the Plutonium Finishing Plant (PFP) Solutions Stabilization subproject. The intent of this plan is to describe how this project will be managed and integrated with other facility stabilization and deactivation activities. This plan supplements the overall integrated plan presented in the Integrated Project Management Plan (IPMP) for the Plutonium Finishing Plant Stabilization and Deactivation Project, HNF-3617. This project plan is the top-level definitive project management document for the PFP Solution Stabilization subproject. It specifies the technical, schedule, requirements and the cost baselines to manage the execution of the Solution Stabilization subproject. Any deviations to the document must be authorized through the appropriate change control process.
Phase stabilities at a glance: Stability diagrams of nickel dipnictides
Bachhuber, F. [University of Regensburg, Institute of Inorganic Chemistry, Universitätsstr. 31, 93040 Regensburg (Germany) [University of Regensburg, Institute of Inorganic Chemistry, Universitätsstr. 31, 93040 Regensburg (Germany); School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland (New Zealand); Rothballer, J.; Weihrich, R., E-mail: richard.weihrich@chemie.uni-r.de [University of Regensburg, Institute of Inorganic Chemistry, Universitätsstr. 31, 93040 Regensburg (Germany); Söhnel, T. [School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland (New Zealand) [School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland (New Zealand); Centre for Theoretical Chemistry and Physics, The New Zealand Institute for Advanced Study, Massey University Auckland, Auckland (New Zealand)
2013-12-07T23:59:59.000Z
In the course of the recent advances in chemical structure prediction, a straightforward type of diagram to evaluate phase stabilities is presented based on an expedient example. Crystal structures and energetic stabilities of dipnictides NiPn{sub 2} (Pn = N, P, As, Sb, Bi) are systematically investigated by first principles calculations within the framework of density functional theory using the generalized gradient approximation to treat exchange and correlation. These dipnictides show remarkable polymorphism that is not yet understood systematically and offers room for the discovery of new phases. Relationships between the concerned structures including the marcasite, the pyrite, the arsenopyrite/CoSb{sub 2}, and the NiAs{sub 2} types are highlighted by means of common structural fragments. Electronic stabilities of experimentally known and related AB{sub 2} structure types are presented graphically in so-called stability diagrams. Additionally, competing binary phases are taken into consideration in the diagrams to evaluate the stabilities of the title compounds with respect to decomposition. The main purpose of the stability diagrams is the introduction of an image that enables the estimation of phase stabilities at a single glance. Beyond that, some of the energetically favored structure types can be identified as potential new phases.
Octonions and vacuum stability
Mikhail V. Gorbatenko
2005-09-22T23:59:59.000Z
The paper addresses one of nontrivial octonion related facts. According to paper gr-qc/0409095, the most stable space-time state is the one described by real Dirac matrices in 11-dimensional space of signature 1(-)&10(+). The internal subspace is 7-dimensional, and its stability is due to a high ``zero'' energy packing density when using an oblique-angled basis from fundamental vectors of lattice E_8 for the spinor degrees of freedom. The nontrivial fact consists in the following: Dirac symbols with octonion matrix elements can be used to describe states of the space of internal degrees of freedom if and only if the space corresponds either to stable vacuum states or states close to the just mentioned ones. The coincidence of the internal space dimension and signature for absolutely different and independent approaches to the consideration of this issue seems to predetermine the internal space vacuum properties and the apparatus, which is able to constitute the basis of the unified interaction theory.
Geometry of Weak Stability Boundaries
Edward Belbruno; Marian Gidea; Francesco Topputo
2012-04-06T23:59:59.000Z
The notion of a weak stability boundary has been successfully used to design low energy trajectories from the Earth to the Moon. The structure of this boundary has been investigated in a number of studies, where partial results have been obtained. We propose a generalization of the weak stability boundary. We prove analytically that, in the context of the planar circular restricted three-body problem, under certain conditions on the mass ratio of the primaries and on the energy, the weak stability boundary about the heavier primary coincides with a branch of the global stable manifold of the Lyapunov orbit about one of the Lagrange points.
Plutonium stabilization and packaging system
NONE
1996-05-01T23:59:59.000Z
This document describes the functional design of the Plutonium Stabilization and Packaging System (Pu SPS). The objective of this system is to stabilize and package plutonium metals and oxides of greater than 50% wt, as well as other selected isotopes, in accordance with the requirements of the DOE standard for safe storage of these materials for 50 years. This system will support completion of stabilization and packaging campaigns of the inventory at a number of affected sites before the year 2002. The package will be standard for all sites and will provide a minimum of two uncontaminated, organics free confinement barriers for the packaged material.
Vortex Lattice Studies in CeCoIn? with H?c
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Das, P.; White, J. S.; Holmes, A. T.; Gerber, S.; Forgan, E. M.; Bianchi, A. D.; Kenzelmann, M.; Zolliker, M.; Gavilano, J. L.; Bauer, E. D.; Sarrao, J. L.; Petrovic, C.; Eskildsen, M. R.
2012-02-01T23:59:59.000Z
We present small angle neutron scattering studies of the vortex lattice (VL) in CeCoIn? with magnetic fields applied parallel (H) to the antinodal [100] and nodal [110] directions. For H II 100], a single VL orientation is observed, while a 90° reorientation transition is found for H II [110]. For both field orientations and VL configurations we find a distorted hexagonal VL with an anisotropy, ?=2.0±0.05. The VL form factor shows strong Pauli paramagnetic effects similar to what have previously been reported for H II [001]. At high fields, above which the upper critical field (Hc2) becomes a first-order transition, an increased disordering of the VL is observed.
Vortex Lattice Studies in CeCoIn? with H?c
DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)
Das, P.; White, J. S.; Holmes, A. T.; Gerber, S.; Forgan, E. M.; Bianchi, A. D.; Kenzelmann, M.; Zolliker, M.; Gavilano, J. L.; Bauer, E. D.; et al
2012-02-01T23:59:59.000Z
We present small angle neutron scattering studies of the vortex lattice (VL) in CeCoIn? with magnetic fields applied parallel (H) to the antinodal [100] and nodal [110] directions. For H II 100], a single VL orientation is observed, while a 90° reorientation transition is found for H II [110]. For both field orientations and VL configurations we find a distorted hexagonal VL with an anisotropy, ?=2.0±0.05. The VL form factor shows strong Pauli paramagnetic effects similar to what have previously been reported for H II [001]. At high fields, above which the upper critical field (Hc2) becomes a first-order transition,more »an increased disordering of the VL is observed.« less
Method for the detection of a magnetic field utilizing a magnetic vortex
Novosad, Valentyn (Chicago, IL); Buchanan, Kristen (Batavia, IL)
2010-04-13T23:59:59.000Z
The determination of the strength of an in-plane magnetic field utilizing one or more magnetically-soft, ferromagnetic member, having a shape, size and material whereas a single magnetic vortex is formed at remanence in each ferromagnetic member. The preferred shape is a thin circle, or dot. Multiple ferromagnetic members can also be stacked on-top of each other and separated by a non-magnetic spacer. The resulting sensor is hysteresis free. The sensor's sensitivity, and magnetic saturation characteristics may be easily tuned by simply altering the material, size, shape, or a combination thereof to match the desired sensitivity and saturation characteristics. The sensor is self-resetting at remanence and therefore does not require any pinning techniques.
Egor Babaev; Boris Svistunov
2014-03-03T23:59:59.000Z
The analysis of nonclassical rotational response of superfluids and superconductors was performed by Onsager (in 1949) \\cite{Onsager} and London (in 1950) \\cite{London} and crucially advanced by Feynman (in 1955) \\cite{Feynman}. It was established that, in thermodynamic limit, neutral superfluids rotate by forming---without any threshold---a vortex lattice. In contrast, the rotation of superconductors at angular frequency ${\\bf \\Omega}$---supported by uniform magnetic field ${\\bf B}_L\\propto {\\bf \\Omega}$ due to surface currents---is of the rigid-body type (London Law). Here we show that, neglecting the centrifugal effects, the behavior of a rotating superconductor is identical to that of a superconductor placed in a uniform fictitious external magnetic filed $\\tilde{\\bf H}=- {\\bf B}_L$. In particular, the isomorphism immediately implies the existence of two critical rotational frequencies in type-2 superconductors.
Peng Ye; Zheng-Cheng Gu
2014-11-20T23:59:59.000Z
Bosonic topological insulators (BTI) in three spatial dimensions are symmetry protected topological (SPT) phases with U(1)$\\rtimes$Z$^T_2$ symmetry, where U(1) is boson particle number conservation, and Z$^T_2$ is time-reversal symmetry with $\\mathcal{T}^2=1$. BTI were first proposed based on the group cohomology theory which suggests two distinct root states, each carrying a $\\mathbb{Z}_2$ index. Soon after, surface anomalous topological orders were proposed to identify different root states of BTI, leading to a new BTI root state beyond the group cohomology classification. Nevertheless, it is still unclear what is the universal physical mechanism for BTI phases and what kinds of microscopic Hamiltonians can realize them. In this paper, we answer the first question by proposing a universal physical mechanism via vortex-line condensation in a superfluid, which can potentially be realized in realistic systems, e.g., helium-4 or cold atoms in optical lattices. Using such a simple physical picture, we find three root phases, of which two of them are classified by group cohomology theory while the other is beyond group cohomology classification. The physical picture also leads to a "natural" bulk dynamic topological quantum field theory (TQFT) description for BTI phases and gives rise to a possible physical pathway towards experimental realizations. Finally, we generalize the vortex-line condensation picture to other symmetries and find that in three dimensions, even for a unitary Z$_2$ symmetry, there could be a nontrivial Z$_2$ SPT phase beyond the group cohomology classification.
Irradiation Stability of Carbon Nanotubes
Aitkaliyeva, Assel
2010-01-14T23:59:59.000Z
Ion irradiation of carbon nanotubes is a tool that can be used to achieve modification of the structure. Irradiation stability of carbon nanotubes was studied by ion and electron bombardment of the samples. Different ion ...
Necessary conditions for stabilization agreements
Yang, Zili.; Jacoby, Henry D.
The Climate Convention calls for stabilization of atmospheric concentrations of greenhouse gases. This paper considers the issues that must be faced in formulating a plan to meet any such target, using a proposed CO2 level ...
Quantum stabilizer codes and beyond
Sarvepalli, Pradeep Kiran
2008-10-10T23:59:59.000Z
QUANTUM STABILIZER CODES AND BEYOND A Dissertation by PRADEEP KIRAN SARVEPALLI Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY August 2008 Major... Subject: Computer Science QUANTUM STABILIZER CODES AND BEYOND A Dissertation by PRADEEP KIRAN SARVEPALLI Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of DOCTOR OF PHILOSOPHY...
Structure, stability and evolution of 3D Rossby vortices in protoplanetary disks
Richard, Samuel; Dizes, Stephane Le
2013-01-01T23:59:59.000Z
Large-scale persistent vortices are known to form easily in 2D disks via the Rossby wave or the baroclinic instability. In 3D, however, their formation and stability is a complex issue and still a matter of debate. We study the formation of vortices by the Rossby wave instability in a stratified inviscid disk and describe their three dimensional structure, stability and long term evolution. Numerical simulations are performed using a fully compressible hydrodynamical code based on a second order finite volume method. We assume a perfect gas law and a non-homentropic adiabatic flow.The Rossby wave instability is found to proceed in 3D in a similar way as in 2D. Vortices produced by the instability look like columns of vorticity in the whole disk thickness; the small vertical motions are related to a weak inclination of the vortex axis appearing during the development of the RWI. Vortices with aspect ratios larger than 6 are unaffected by the elliptical instability. They relax to a quasi-steady columnar structu...
Material Stabilization Project Management Plan
SPEER, D.R.
1999-09-01T23:59:59.000Z
This plan presents the overall objectives, description, justification and planning for the plutonium Finishing Plant (PFP) Materials Stabilization project. The intent of this plan is to describe how this project will be managed and integrated with other facility stabilization and deactivation activities. This plan supplements the overall integrated plan presented in the Plutonium Finishing Plant Integrated Project Management Plan (IPMP), HNF-3617, Rev. 0. This is the top-level definitive project management document that specifies the technical (work scope), schedule, and cost baselines to manager the execution of this project. It describes the organizational approach and roles/responsibilities to be implemented to execute the project. This plan is under configuration management and any deviations must be authorized by appropriate change control action. Materials stabilization is designated the responsibility to open and stabilize containers of plutonium metal, oxides, alloys, compounds, and sources. Each of these items is at least 30 weight percent plutonium/uranium. The output of this project will be containers of materials in a safe and stable form suitable for storage pending final packaging and/or transportation offsite. The corrosion products along with oxides and compounds will be stabilized via muffle furnaces to reduce the materials to high fired oxides.
Sergey K. Nemirovskii
2005-05-18T23:59:59.000Z
Kinetics of merging and breaking down vortex loops is the important part of the whole vortex tangle dynamics. Another part is the motion of individual lines, which obeys the Biot-Savart law in presence of friction force and of applied external velocity fields if any. In the present work we evaluate the coefficients of the reconnection rates $A(l_{1},l_{2},l)$ and $B(l,l_{1},l_{2})$. Quantity $A$ is a number (per unit of time and per unit of volume) of events, when two loops with lengths $l_{1}$and $l_{2}$ collide and form the single loop of length $ l=l_{1}+l_{2}$. Quantity $% B(l,l_{1},l_{2}) $ describes the rate of events, when the single loop of the length $l$ breaks down into two the daughter loops of lengths $ l_{1}$ and $l_{2}$. These quantities ave evaluated as the averaged numbers of zeroes of vector $\\mathbf{S}%_{s}(\\xi_{2},\\xi_{1},t)$ connecting two points on the loops of $\\xi_{2}$ and $ \\xi_{1}$ at moment of time $t$. Statistics of the individual loops is taken from the Gaussian model of vortex tangle. PACS-number 67.40
Harold Schock; Farhad Jaberi; Ahmed Naguib; Guoming Zhu; David Hung
2007-12-31T23:59:59.000Z
This report describes the work completed over a two and one half year effort sponsored by the US Department of Energy. The goal was to demonstrate the technology needed to produce a highly efficient engine enabled by several technologies which were to be developed in the course of the work. The technologies included: (1) A low-pressure direct injection system; (2) A mass air flow sensor which would measure the net airflow into the engine on a per cycle basis; (3) A feedback control system enabled by measuring ionization current signals from the spark plug gap; and (4) An infinitely variable cam actuation system based on a pneumatic-hydraulic valve actuation These developments were supplemented by the use of advanced large eddy simulations as well as evaluations of fuel air mixing using the KIVA and WAVE models. The simulations were accompanied by experimental verification when possible. In this effort a solid base has been established for continued development of the advanced engine concepts originally proposed. Due to problems with the valve actuation system a complete demonstration of the engine concept originally proposed was not possible. Some of the highlights that were accomplished during this effort are: (1) A forward-backward mass air flow sensor has been developed and a patent application for the device has been submitted. We are optimistic that this technology will have a particular application in variable valve timing direct injection systems for IC engines. (2) The biggest effort on this project has involved the development of the pneumatic-hydraulic valve actuation system. This system was originally purchased from Cargine, a Swedish supplier and is in the development stage. To date we have not been able to use the actuators to control the exhaust valves, although the actuators have been successfully employed to control the intake valves. The reason for this is the additional complication associated with variable back pressure on the exhaust valves when they are opened. As a result of this effort, we have devised a new design and have filed for a patent on a method of control which is believed to overcome this problem. The engine we have been working with originally had a single camshaft which controlled both the intake and exhaust valves. Single cycle lift and timing control was demonstrated with this system. (3) Large eddy simulations and KIVA based simulations were used in conjunction with flow visualizations in an optical engine to study fuel air mixing. During this effort we have devised a metric for quantifying fuel distribution and it is described in several of our papers. (4) A control system has been developed to enable us to test the benefits of the various technologies. This system used is based on Opal-RT hardware and is being used in a current DOE sponsored program.
Fu, Hailong
2010-07-14T23:59:59.000Z
for increasing protein stability. Finally, using a combination of eight previously identified stabilizing mutations; we successfully designed two RNase Sa variants (7S, 8S) that have both much higher Tms and conformational stabilities than wild-type protein over...
The effect of disorder on the critical points in the vortex phase diagram of YBCO
Crabtree, G. W.; Kwok, W. K.; Paulius, L. M.; Petrean, A. M.; Olsson, R. J.; Karapetrov, G.; Tobos, V.; Moulton, W. G.
2000-01-19T23:59:59.000Z
The effect of line disorder induced by heavy ion irradiation and of point disorder induced by proton and electron irradiation on the upper and lower critical points in the vortex phase diagram of YBCO is presented. The authors find that dilute line disorder induces a Bose glass transition at low fields which is replaced at the lower critical point by first order melting at higher fields. Strong pinning point defects raise the lower critical point, while weak pinning point defects have little or no effect on the lower critical point. The upper critical point is lowered by point disorder, but raised by line disorder. First order melting is suppressed by point disorder in two ways, by lowering of the upper critical point only for weak point pins, or by merging of the upper and lower critical points for strong point pins. The differing responses of the upper and lower critical points to line and point disorder can be understood in a picture of transverse and longitudinal spatial fluctuations.
Fu, T.T. [Naval Civil Engineering Lab., Port Hueneme, CA (United States); Nieh, S. [Catholic Univ. of America, Washington, DC (United States). Combustion and Multiphase Flows Lab.
1990-11-01T23:59:59.000Z
This is the final report for Interagency Agreement DE-AI22-87PC79660 on ``Combustion Test`` for vortex combustor (VC) development for commercial applications. The work culminated in the successful demonstration of a 2 MB/H proof-of-concept (POC) model firing coal-water fuel (CWF). This development is concerned with a new concept in combustion, and was a general lack of relevant information. The work therefore began (in addition to the companion cold flow modeling study) with the design and test of two subscale models (0.15 and 0.3 MB/H) and one full scale model (3 MB/H) to obtain the needed information. With the experience gained, the 2 MB/H POC model was then designed and demonstrated. Although, these models were designed somewhat differently from one another, they all performed well and demonstrated the superiority of the concept. In summary, test results have shown that VC can be fired on several coal fuels (CWF, dry ultrafine coal, utility grind pulverized coal) at high combustion efficiency (>99%), high firing intensity (up to 0.44 MB/H-ft{sup 3}), and at temperatures sufficiently low or dry ash removal. The combustion process is completed totally inside the combustor. Conventional combustion enhancement techniques such as: preheating (air and/or fuel), pre-combustion, and post combustion are not needed.
Development of a vortex combustor (VC) for space/water heating applications (combustion tests)
Fu, T.T. (Naval Civil Engineering Lab., Port Hueneme, CA (United States)); Nieh, S. (Catholic Univ. of America, Washington, DC (United States). Combustion and Multiphase Flows Lab.)
1990-11-01T23:59:59.000Z
This is the final report for Interagency Agreement DE-AI22-87PC79660 on Combustion Test'' for vortex combustor (VC) development for commercial applications. The work culminated in the successful demonstration of a 2 MB/H proof-of-concept (POC) model firing coal-water fuel (CWF). This development is concerned with a new concept in combustion, and was a general lack of relevant information. The work therefore began (in addition to the companion cold flow modeling study) with the design and test of two subscale models (0.15 and 0.3 MB/H) and one full scale model (3 MB/H) to obtain the needed information. With the experience gained, the 2 MB/H POC model was then designed and demonstrated. Although, these models were designed somewhat differently from one another, they all performed well and demonstrated the superiority of the concept. In summary, test results have shown that VC can be fired on several coal fuels (CWF, dry ultrafine coal, utility grind pulverized coal) at high combustion efficiency (>99%), high firing intensity (up to 0.44 MB/H-ft[sup 3]), and at temperatures sufficiently low or dry ash removal. The combustion process is completed totally inside the combustor. Conventional combustion enhancement techniques such as: preheating (air and/or fuel), pre-combustion, and post combustion are not needed.
Twisted toroidal vortex-solitons in inhomogeneous media with repulsive nonlinearity
Y. V. Kartashov; B. A. Malomed; Y. Shnir; L. Torner
2014-12-05T23:59:59.000Z
Toroidal modes in the form of so-called Hopfions, with two independent winding numbers, a hidden one (twist, s), which characterizes a circular vortex thread embedded into a three-dimensional soliton, and the vorticity around the vertical axis m, appear in many fields, including the field theory, ferromagnetics, and semi- and superconductors. Such topological states are normally generated in multi-component systems, or as trapped quasi-linear modes in toroidal potentials. We uncover that stable solitons with this structure can be created, without any linear potential, in the single-component setting with the strength of repulsive nonlinearity growing fast enough from the center to the periphery, for both steep and smooth modulation profiles. Toroidal modes with s=1 and vorticity m=0,1,2 are produced. They are stable for m1. An approximate analytical solution is obtained for the twisted ring with s=1, m=0. Under the application of an external torque, it rotates like a solid ring. The setting can be implemented in BEC, by means of the Feshbach resonance controlled by inhomogene-ous magnetic fields.
Quantum stabilizer codes and beyond
Pradeep Kiran Sarvepalli
2008-10-14T23:59:59.000Z
The importance of quantum error correction in paving the way to build a practical quantum computer is no longer in doubt. This dissertation makes a threefold contribution to the mathematical theory of quantum error-correcting codes. Firstly, it extends the framework of an important class of quantum codes -- nonbinary stabilizer codes. It clarifies the connections of stabilizer codes to classical codes over quadratic extension fields, provides many new constructions of quantum codes, and develops further the theory of optimal quantum codes and punctured quantum codes. Secondly, it contributes to the theory of operator quantum error correcting codes also called as subsystem codes. These codes are expected to have efficient error recovery schemes than stabilizer codes. This dissertation develops a framework for study and analysis of subsystem codes using character theoretic methods. In particular, this work establishes a close link between subsystem codes and classical codes showing that the subsystem codes can be constructed from arbitrary classical codes. Thirdly, it seeks to exploit the knowledge of noise to design efficient quantum codes and considers more realistic channels than the commonly studied depolarizing channel. It gives systematic constructions of asymmetric quantum stabilizer codes that exploit the asymmetry of errors in certain quantum channels.
Stabilization of Layered Metal Oxides
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
stabilizing cations and anions (NH 4 ) 3 AlF 6 ; NH 4 PF 6 ; NH 4 BF 4 in water, methanol, etc molarity of solutions 2.5 x 10 -3 M pH 6.0 - 6.5 Composition used:...
Stability of Molten Core Materials
Layne Pincock; Wendell Hintze
2013-01-01T23:59:59.000Z
The purpose of this report is to document a literature and data search for data and information pertaining to the stability of nuclear reactor molten core materials. This includes data and analysis from TMI-2 fuel and INL’s LOFT (Loss of Fluid Test) reactor project and other sources.
Material stabilization characterization management plan
GIBSON, M.W.
1999-08-31T23:59:59.000Z
This document presents overall direction for characterization needs during stabilization of SNM at the Plutonium Finishing Plant (PFP). Technical issues for needed data and equipment are identified. Information on material categories and links to vulnerabilities are given. Comparison data on the material categories is discussed to assist in assessing the relative risks and desired processing priority.
Stability of Gas-Fluidized Beds
Mandich, Kevin Matthew
R. The mechanics of fluidised beds: Part I: The stability ofR. The mechanics of fluidised beds: Part I: The stability ofof an Inclined Fluidised Bed. Kagaku Kogaku Ronbunshu, 15 (
Factors influencing antioxidant phytochemical stability of teas
Kim, Youngmok
2009-05-15T23:59:59.000Z
polyphenolic profile of teas. To present fundamental information of phytochemical stability during tea storage, studies to determine the impacts of tea processing, different packaging materials, and various storage conditions on the phytochemical stability were...
TILT STABILITY, UNIFORM QUADRATIC GROWTH, AND STRONG ...
2012-05-08T23:59:59.000Z
Tilt stability, variational analysis, subdifferentials, quadratic growth, strong metric .... Some convex analysis. ..... Example 3.5 (Failure of subdifferential continuity).
Stabilization of Platinum Nanoparticle Electrocatalysts for Oxygen...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Platinum Nanoparticle Electrocatalysts for Oxygen Reduction Using Poly(diallyldimethylammonium chloride). Stabilization of Platinum Nanoparticle Electrocatalysts for Oxygen...
A Stability of LCLS Linac Modulators
Decker, F.-J.; Krasnykh, A.; Morris, B.; Nguyen, M.; /SLAC
2012-06-13T23:59:59.000Z
Information concerning to a stability of LCLS RF linac modulators is allocated in this paper. In general a 'pulse-to-pulse' modulator stability (and RF phase as well) is acceptable for the LCLS commission and FEL programs. Further modulator stability improvements are possible and approaches are discussed based on our experimental results.
Trading Away Financial Stability in Colombia
Tufts University
Trading Away Financial Stability in Colombia: Capital Controls and the US-Colombia Trade Agreement@bu.edu #12;Trading Away Financial Stability in Colombia: Capital Controls and the US-Colombia Trade Agreement SerieBrief # 66 | Abril 2011 Trading Away Financial Stability in Colombia: Capital Controls and the US-Colombia
STABILITY CONDITIONS IN PIECEWISE SMOOTH DYNAMICAL SYSTEMS
Herrmann, Samuel
-fold singularities. More specifically, we are interested in discussing stability problems of such systems around of those of Asymptotic and Lya- punov stability respectively. For technical reasons they will be presented in Subsection 2.6. Our main results exhibit conditions for the A- and L- stability of a two-fold singularity
Stability diagram of colliding beams
Buffat, X; Mounet, N; Pieloni, T
2014-01-01T23:59:59.000Z
The effect of the beam-beam interactions on the stability of impedance mode is discussed. The detuning is evaluated by the means of single particle tracking in arbitrarily complex collision configurations, including lattice non-linearities, and used to numerically evaluate the dispersion integral. This approach also allows the effect of non-Gaussian distributions to be considered. Distributions modified by the action of external noise are discussed.
O'Brien, James Edward; Sohal, Manohar Singh; Huff, George Albert
2002-08-01T23:59:59.000Z
A combined experimental and numerical investigation is under way to investigate heat transfer enhancement techniques that may be applicable to large-scale air-cooled condensers such as those used in geothermal power applications. The research is focused on whether air-side heat transfer can be improved through the use of finsurface vortex generators (winglets,) while maintaining low heat exchanger pressure drop. A transient heat transfer visualization and measurement technique has been employed in order to obtain detailed distributions of local heat transfer coefficients on model fin surfaces. Pressure drop measurements have also been acquired in a separate multiple-tube row apparatus. In addition, numerical modeling techniques have been developed to allow prediction of local and average heat transfer for these low-Reynolds-number flows with and without winglets. Representative experimental and numerical results presented in this paper reveal quantitative details of local fin-surface heat transfer in the vicinity of a circular tube with a single delta winglet pair downstream of the cylinder. The winglets were triangular (delta) with a 1:2 height/length aspect ratio and a height equal to 90% of the channel height. Overall mean fin-surface Nusselt-number results indicate a significant level of heat transfer enhancement (average enhancement ratio 35%) associated with the deployment of the winglets with oval tubes. Pressure drop measurements have also been obtained for a variety of tube and winglet configurations using a single-channel flow apparatus that includes four tube rows in a staggered array. Comparisons of heat transfer and pressure drop results for the elliptical tube versus a circular tube with and without winglets are provided. Heat transfer and pressure-drop results have been obtained for flow Reynolds numbers based on channel height and mean flow velocity ranging from 700 to 6500.
Stability-Constrained Optimal Power Flow and Its Application to Pricing Power System Stabilizers
Cañizares, Claudio A.
1 Stability-Constrained Optimal Power Flow and Its Application to Pricing Power System Stabilizers locational marginal prices. A power system stabilizer (PSS) is then introduced in the test system Terms-- Angle stability, power system oscillations, elec- tricity markets, optimal power flow
Nonbinary Codeword Stabilized Quantum Codes
Xie Chen; Bei Zeng; Isaac L. Chuang
2008-08-22T23:59:59.000Z
The codeword stabilized (CWS) quantum codes formalism presents a unifying approach to both additive and nonadditive quantum error-correcting codes (arXiv:0708.1021 [quant-ph]), but only for binary states. Here we generalize the CWS framework to the nonbinary case (of both prime and nonprime dimension) and map the search for nonbinary quantum codes to a corresponding search problem for classical nonbinary codes with specific error patterns. We show that while the additivity properties of nonbinary CWS codes are similar to the binary case, the structural properties of the nonbinary codes differ substantially from the binary case, even for prime dimensions. In particular, we identify specific structure patterns of stabilizer groups, based on which efficient constructions might be possible for codes that encode more dimensions than any stabilizer codes of the same length and distance; similar methods cannot be applied in the binary case. Understanding of these structural properties can help prune the search space and facilitate the identification of good nonbinary CWS codes.
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What'sis Taking Over Our Instagram Secretary900 Special Report:Spotlight: Bryantis here April and Error
Bounds on Effective Hamiltonians for Stabilizer Codes
Stephen S. Bullock; Dianne P. O'Leary
2008-02-05T23:59:59.000Z
This manuscript introduces various notions of k-locality of stabilizer codes inherited from the associated stabilizer groups. A choice of generators for the group leads to a Hamiltonian with the code in its groundspace, while a Hamiltonian holding the code in its groundspace might be called effective if its locality is less than that of a natural choice of generators (or any choice). This paper establishes some conditions under which effective Hamiltonians for stabilizer codes do not exist. Our results simplify in the cases of Calderbank-Shor-Steane stabilizer codes and topologically-ordered stabilizer codes arising from surface cellulations.
Van Dusen, Maurice Verne
1970-01-01T23:59:59.000Z
. S. McCulley, Dr. V. P. Jones, Dr. B. M. Rao and Dr. J. L. Rand for their patience and guidance, without which the completion of this thesis would not have been possible. A special thanks is offered to Mr. T. J. Meiller for his assistance 'n.... Commercial Aircraft, " Aviation Week 4~9. I~hl, 91 92 N 10 M* 9 19&0 p 121 Tab1e 1 Geometry of vortex generators. GENERATOR NUMBER b (inches) (degrees) 10 20 10 20 21 Table 2 Experimentally determined vortex centers. I Z 0 TEST SECTION ORIGIN...
Code constructions and code families for nonbinary quantum stabilizer code
Ketkar, Avanti Ulhas
2005-11-01T23:59:59.000Z
Stabilizer codes form a special class of quantum error correcting codes. Nonbinary quantum stabilizer codes are studied in this thesis. A lot of work on binary quantum stabilizer codes has been done. Nonbinary stabilizer codes have received much...
Tritium systems test assembly stabilization
Jasen, W. G. (William G.); Michelotti, R. A. (Roy A.); Anast, K. R. (Kurt R.); Tesch, Charles
2004-01-01T23:59:59.000Z
The Tritium Systems Test Assembly (TSTA) was a facility dedicated to tritium technology Research and Development (R&D) primarily for future fusion power reactors. The facility was conceived in mid 1970's, operations commenced in early 1980's, stabilization and deactivation began in 2000 and were completed in 2003. The facility will remain in a Surveillance and Maintenance (S&M) mode until the Department of Energy (DOE) funds demolition of the facility, tentatively in 2009. A safe and stable end state was achieved by the TSTA Facility Stabilization Project (TFSP) in anticipation of long term S&M. At the start of the stabilization project, with an inventory of approximately 140 grams of tritium, the facility was designated a Hazard Category (HC) 2 Non-Reactor Nuclear facility as defined by US Department of Energy standard DOE-STD-1027-92 (1997). The TSTA facility comprises a laboratory area, supporting rooms, offices and associated laboratory space that included more than 20 major tritium handling systems. The project's focus was to reduce the tritium inventory by removing bulk tritium, tritiated water wastes, and tritium-contaminated high-inventory components. Any equipment that remained in the facility was stabilized in place. All of the gloveboxes and piping were rendered inoperative and vented to atmosphere. All equipment, and inventoried tritium contamination, remaining in the facility was left in a safe-and-stable state. The project used the End Points process as defined by the DOE Office of Environmental Management (web page http://www.em.doe.- gov/deact/epman.htmtlo) document and define the end state required for the stabilization of TSTA Facility. The End Points process added structure that was beneficial through virtually all phases of the project. At completion of the facility stabilization project the residual tritium inventory was approximately 3,000 curies, considerably less than the 1.6-gram threshold for a HC 3 facility. TSTA is now designated as a Radiological Facility. Innovative approaches were employed for characterization and removal of legacy wastes and high inventory components. Major accomplishments included: (1) Reduction of tritium inventory, elimination of chemical hazards, and identification and posting of remaining hazards. (2) Removal of legacy wastes. (3) Transferred equipment for reuse in other DOE projects, including some at other DOE facilities. (4) Transferred facility in a safe and stable condition to the S&M organization. The project successfully completed all project goals and the TSTA facility was transferred into S&M on August 1,2003. This project demonstrates the benefit of radiological inventory reduction and the removal of legacy wastes to achieve a safe and stable end state that protects workers and the environment pending eventual demolition of the facility.
Paul, A.; Mandal, G.; Amin, M. R. [Department of Electronics and Communications Engineering, East West University, Aftabnagar, Dhaka 1212 (Bangladesh)] [Department of Electronics and Communications Engineering, East West University, Aftabnagar, Dhaka 1212 (Bangladesh); Mamun, A. A. [Department of Physics, Jahangirnagar University, Savar, Dhaka 1342 (Bangladesh)] [Department of Physics, Jahangirnagar University, Savar, Dhaka 1342 (Bangladesh)
2013-10-15T23:59:59.000Z
The nonlinear propagation of dust-acoustic (DA) waves in an unmagnetized dusty plasma consisting of nonthermal electrons, vortex-like (trapped) distributed ions and mobile negative dust have been investigated by employing the reductive perturbation technique. The effects of nonthermal electrons and trapped ions are found to modify the properties of the DA solitary waves.
Moshchalkov, Victor V.
Dipole-Induced Vortex Ratchets in Superconducting Films with Arrays of Micromagnets C. C. de Souza. By carrying out transport measurements with ac drive, we observed experimentally a recently predicted ratchet on the phenomenon known as ratchet effect [8]. As recently proposed by Carneiro [9], a different way to create
Van Gorder, Robert A., E-mail: rav@knights.ucf.edu [Department of Mathematics, University of Central Florida, Orlando, Florida 32816-1364 (United States)
2014-11-15T23:59:59.000Z
In R. A. Van Gorder, “General rotating quantum vortex filaments in the low-temperature Svistunov model of the local induction approximation,” Phys. Fluids 26, 065105 (2014) I discussed properties of generalized vortex filaments exhibiting purely rotational motion under the low-temperature Svistunov model of the local induction approximation. Such solutions are stationary in terms of translational motion. In the Comment [N. Hietala, “Comment on ‘General rotating quantum vortex filaments in the low-temperature Svistunov model of the local induction approximation’ [Phys. Fluids 26, 065105 (2014)],” Phys. Fluids 26, 119101 (2014)], the author criticizes my paper for not including translational motion (although it was clearly stated that the filament motion was assumed rotational). As it turns out, if one is interested in studying the geometric structure of solutions (which was the point of my paper), one obtains the needed qualitative results on the structure of such solutions by studying the purely rotational case. Nevertheless, in this Response I shall discuss the vortex filaments that have both rotational and translational motions. I then briefly discuss why one might want to study such generalized rotating filament solutions, in contrast to simple the standard helical or planar examples (which are really special cases). I also discuss how one can study the time evolution of filaments which exhibit more complicated dynamics than pure translation and rotation. Doing this, one can study non-stationary solutions which initially appear purely rotational and gradually display other dynamics as the filaments evolve.
Boyer, Edmond
the dissipation of energy in the von K´arm´an street behind the blades so that the per- formances of the fan Vortex Designed axial-flow fan C. Sarrafa , H. Nouria , F. Raveleta, , F. Bakira aArts et Metiers Paris
Codeword stabilized quantum codes on subsystems
Jeonghwan Shin; Jun Heo; Todd A. Brun
2012-08-29T23:59:59.000Z
Codeword stabilized quantum codes provide a unified approach to constructing quantum error-correcting codes, including both additive and non-additive quantum codes. Standard codeword stabilized quantum codes encode quantum information into subspaces. The more general notion of encoding quantum information into a subsystem is known as an operator (or subsystem) quantum error correcting code. Most operator codes studied to date are based in the usual stabilizer formalism. We introduce operator quantum codes based on the codeword stabilized quantum code framework. Based on the necessary and sufficient conditions for operator quantum error correction, we derive a error correction condition for operator codeword stabilized quantum codes. Based on this condition, the word operators of a operator codeword stabilized quantum code are constructed from a set of classical binary errors induced by generators of the gauge group. We use this scheme to construct examples of both additive and non-additive codes that encode quantum information into a subsystem.
Singular Limits in Polymer Stabilized Liquid Crystals
1910-31-00T23:59:59.000Z
We investigate equilibrium configurations for a polymer stabilized liquid crys- tal material ... eling the cross section of the liquid crystal-polymer fiber composite.
Stabilization of Electrocatalytic Metal Nanoparticles at Metal...
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Electrocatalytic Metal Nanoparticles at Metal-Metal Oxide-Graphene Triple Junction Points. Stabilization of Electrocatalytic Metal Nanoparticles at Metal-Metal Oxide-Graphene...
HOLOMORPHIC MOTIONS AND STRUCTURAL STABILITY FOR ...
1910-70-80T23:59:59.000Z
namics in one variable, we prove the structural stability of hyperbolic polynomial automor- phisms in ..... This extension is characterized by a harmonic Beltrami.
Optimization Online - Quantitative Stability Analysis of Stochastic ...
Jie Zhang
2015-06-03T23:59:59.000Z
Jun 3, 2015 ... Quantitative Stability Analysis of Stochastic Quasi-Variational Inequality Problems and Applications. Jie Zhang(zhangjie04212001 ***at*** ...
Stabilization of polyaniline solutions through additives
Wrobleski, D.A.; Benicewicz, B.C.
1996-12-10T23:59:59.000Z
A stabilized non-conductive polyaniline solution comprising from about 1 to about 10 percent by weight polyaniline or a polyaniline derivative, from about 90 to about 99 percent by weight N-methylpyrrolidone, and from about 0.5 percent by weight to about 15 percent by weight of a solution stabilizing additive selected from the group consisting of hindered amine light stabilizers, polymeric amines, and dialkylamines, percent by weight of additive based on the total weight of polyaniline or polyaniline derivative is provided together with a method for stabilizing a polyaniline solution. 4 figs.
Stabilization of polyaniline solutions through additives
Wrobleski, Debra A. (Los Alamos, NM); Benicewicz, Brian C. (Los Alamos, NM)
1996-01-01T23:59:59.000Z
A stabilized non-conductive polyaniline solution comprising from about 1 to bout 10 percent by weight polyaniline or a polyaniline derivative, from about 90 to about 99 percent by weight N-methylpyrrolidone, and from about 0.5 percent by weight to about 15 percent by weight of a solution stabilizing additive selected from the group consisting of hindered amine light stabilizers, polymeric amines, and dialkylamines, percent by weight of additive based on the total weight of polyaniline or polyaniline derivative is provided together with a method for stabilizing a polyaniline solution.
Chemically stabilized ionomers containing inorganic fillers
Roelofs, Mark Gerrit
2013-12-31T23:59:59.000Z
Ionomeric polymers that are chemically stabilized and contain inorganic fillers are prepared, and show reduced degradation. The ionomers care useful in membranes and electrochemical cells.
Adaptive Stabilization of Nonlinear Stochastic Systems
Florchinger, P. [URA CNRS No. 399, Departement de Mathematiques, UFR MIM, Universite de Metz, Ile du Saulcy, F 57045 Metz Cedex (France)
1998-07-15T23:59:59.000Z
The purpose of this paper is to study the problem of asymptotic stabilization in probability of nonlinear stochastic differential systems with unknown parameters. With this aim, we introduce the concept of an adaptive control Lyapunov function for stochastic systems and we use the stochastic version of Artstein's theorem to design an adaptive stabilizer. In this framework the problem of adaptive stabilization of a nonlinear stochastic system is reduced to the problem of asymptotic stabilization in probability of a modified system. The design of an adaptive control Lyapunov function is illustrated by the example of adaptively quadratically stabilizable in probability stochastic differential systems.
Pneumatic vibratory cleaner conveyor for sugarcane
Oliveira, Roberto Costa de
1983-01-01T23:59:59.000Z
RESULTS page 14 59 5. AIR VELOCITY (M/5) ALONG THE EVEN SLOTS FOR FAN SPEED OF 200 RPM 137 6. AIR VELOCITY (M/S) ALONG THE EVEN SLOTS FOR FAN SPEED QF 400 RPM 138 7. AIR VELOCITY (M/5) ALONG THE EVEN SLOTS FOR FAN SPEED OF 600 RPM 139 8. AIR... in the cane is extremely detzimental to the sugar recovery: Azcenaux and Davidson (1944) estimated that tne sugar recovery is lessened in the order of 1 pound of sugar for every 30 pounds of leaves pez ton of cane. At this rate, 6% leaves accompany' ng...
ORIGINAL ARTICLE Pneumatic Energy Sources for Autonomous
Wood, Robert
research projects using combustion (methane and butane) and monopropellant decomposition (hydrogen per extensive system-level development. Hydrogen peroxide decomposition requires not only few additional parts mobile robotics grows, the most common energy source remains a tether to a sta- tionary compressor. While
Pneumatic vibratory cleaner conveyor for sugarcane
Oliveira, Roberto Costa de
1983-01-01T23:59:59.000Z
along the x axis will be: Z F = F cosp ? Wsinf = mx x 2 mx ? CAp [v +( s-x) cosP-ysinP] A cosp/2 + Wsing = 0 [21] l, ikewise, the summation of all forces along y axis will be: Z F = F sing - Wcosg = my y A 2 my ? CAp[v (s-x)cosg-ysinP] sind/2... (y/x) The aerodynamic drag force will be: F = CApv /2 = CAp(x +y )/2 2 '2 '2 D As done in the previous sections, the summation of forces and moments will be: Z F ~ ? F cos6 - Wein/ = mx x D mx + CAp(x +y )cos[arctan(y/x)]/2 + Wein/ = 0 2 2 [2Z...
NEURAL NETWORKS FOR PNEUMATIC ACTUATOR FAULT DETECTION
Drummond, Tom
signals can improve safety and efficiency and can help to re duce downtime and plant maintenance require of Engineering Science, UK \\Lambda\\Lambda University of the Witwatersrand, Department of Electrical Engineering, South Africa \\Lambda\\Lambda\\Lambda Berkley University, Electrical Engineering and Computer Science
Analysis of Transient Thickness of Pneumatic Foams
Pilon, Laurent; Fedorov, Andrei G.; Viskanta, Raymond
2002-01-01T23:59:59.000Z
Engineering of Chemical Hrma, P. (1990). Model for a steadyWasan, 1985). According to Hrma (1990), the lifetime of aDjabbarah and Wasan, 1985; Hrma, 1990): T The lifetime r c T
Pneumatic wall-locking geophone system
Kuhlman, Harland L. (Minneapolis, MN); Cumerlato, Calvin L. (Minneapolis, MN); Tweeton, Daryl R. (Apple Valley, MN)
1991-01-01T23:59:59.000Z
A seismic signal receiving system is provided for use in boreholes to receive seismic waves in carrying out geophysical investigations. The system includes three pairs of opposed plates, each of the pairs of plates including oppositely facing outer surfaces for engagement with opposite sides of a borehole. A seismic receiver is mounted on the inner surface of each of the plates for receiving seismic signals. A double-acting, fluid-operated actuator selectively causes relative movement of the plates of the pairs of plates away from each other to provide expansion thereof so as to enable the plates to engage the walls of a borehole and selectively causes relative movement of the plates of the pairs of plates toward each other to provide retraction thereof so as to enable the system to be removed from a borehole. The pairs of plates each comprise a relatively long plate and a relatively short plate. An expandable linkage interconnects the long plates at the distal ends thereof. The plates are mechanically biassed into the retracted state so that the plates return to this state in the event of a system failure.
Pneumatic Conveyance Device - Energy Innovation Portal
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AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level:Energy: Grid Integration Redefining What's Possible for RenewableSpeedingBiomassPPPOPetroleum38 (1996)representative ofPlant
Önder, Asim; Meyers, Johan, E-mail: johan.meyers@mech.kuleuven.be [Department of Mechanical Engineering, KU Leuven, Celestijnenlaan 300A, B3001 Leuven (Belgium)
2014-07-15T23:59:59.000Z
We study the near field of a zero-net-mass-flux (ZNMF) actuated round jet using direct numerical simulations. The Reynolds number of the jet Re{sub D} = 2000 and three ZNMF actuators are used, evenly distributed over a circle, and directed towards the main jet. The actuators are triggered in phase, and have a relatively low momentum coefficient of C{sub ?} = 0.0049 each. We study four different control frequencies with Strouhal numbers ranging from St{sub D} = 0.165 to St{sub D} = 1.32; next to that, also two uncontrolled baseline cases are included in the study. We find that this type of ZNMF actuation leads to strong deformations of the near-field jet region that are very similar to those observed for non-circular jets. At the end of the jet's potential core (x/D = 5), the jet-column cross section is deformed into a hexagram-like geometry that results from strong modifications of the vortex structures. Two mechanisms lead to these modifications, i.e., (i) self-deformation of the jet's primary vortex rings started by distortions in their azimuthal curvature by the actuation, and (ii) production of side jets by the development and subsequent detachment of secondary streamwise vortex pairs. Further downstream (x/D = 10), the jet transforms into a triangular pattern, as the sharp corner regions of the hexagram entrain fluid and spread. We further investigate the global characteristics of the actuated jets. In particular when using the jet preferred frequency, i.e., St{sub D} = 0.33, parameters such as entrainment, centerline decay rate, and mean turbulent kinetic energy are significantly increased. Furthermore, high frequency actuation, i.e., St{sub D} = 1.32, is found to suppress the mechanisms leading to large scale structure growth and turbulent kinetic energy production. The simulations further include a passive scalar equation, and passive scalar mixing is also quantified and visualized.
Surface rheology and interface stability.
Yaklin, Melissa A.; Cote, Raymond O.; Moffat, Harry K.; Grillet, Anne Mary; Walker, Lynn; Koehler, Timothy P.; Reichert, Matthew D. (Carnegie Mellon University, Pittsburgh, PA); Castaneda, Jaime N.; Mondy, Lisa Ann; Brooks, Carlton, F.
2010-11-01T23:59:59.000Z
We have developed a mature laboratory at Sandia to measure interfacial rheology, using a combination of home-built, commercially available, and customized commercial tools. An Interfacial Shear Rheometer (KSV ISR-400) was modified and the software improved to increase sensitivity and reliability. Another shear rheometer, a TA Instruments AR-G2, was equipped with a du Nouey ring, bicone geometry, and a double wall ring. These interfacial attachments were compared to each other and to the ISR. The best results with the AR-G2 were obtained with the du Nouey ring. A Micro-Interfacial Rheometer (MIR) was developed in house to obtain the much higher sensitivity given by a smaller probe. However, it was found to be difficult to apply this technique for highly elastic surfaces. Interfaces also exhibit dilatational rheology when the interface changes area, such as occurs when bubbles grow or shrink. To measure this rheological response we developed a Surface Dilatational Rheometer (SDR), in which changes in surface tension with surface area are measured during the oscillation of the volume of a pendant drop or bubble. All instruments were tested with various surfactant solutions to determine the limitations of each. In addition, foaming capability and foam stability were tested and compared with the rheology data. It was found that there was no clear correlation of surface rheology with foaming/defoaming with different types of surfactants, but, within a family of surfactants, rheology could predict the foam stability. Diffusion of surfactants to the interface and the behavior of polyelectrolytes were two subjects studied with the new equipment. Finally, surface rheological terms were added to a finite element Navier-Stokes solver and preliminary testing of the code completed. Recommendations for improved implementation were given. When completed we plan to use the computations to better interpret the experimental data and account for the effects of the underlying bulk fluid.
Coarse-grained simulations of vortex dynamics and transition in complex high-Re flows
Grinstein, Fernando F [Los Alamos National Laboratory
2011-01-21T23:59:59.000Z
Turbulent flow complexity in applications in engineering, geophysics and astrophysics typically requires achieving accurate and dependable large scale predictions of highly nonlinear processes with under-resolved computer simulation models. Laboratory observations typically demonstrate the end outcome of complex non-linear three-dimensional physical processes with many unexplained details and mechanisms. Carefully controlled computational experiments based on the numerical solution of the conservation equations for mass, momentum, and energy, provide insights into the underlying flow dynamics. Relevant computational fluid dynamics issues to be addressed relate to the modeling of the unresolved tlow conditions at the subgrid scale (SGS) level - within a computational cell, and at the supergrid (SPG) scale - at initialization and beyond computational boundaries. SGS and SPG information must be prescribed for closure of the equations solved numerically. SGS models appear explicitly or implicitly as additional source tenns in the modified flow equations solved by the numerical solutions being calculated, while SPG models provide the necessary set of initial and boundary conditions that must be prescribed to ensure unique well-posed solutions. From this perspective, it is clear that the simulation process is inherently determined by the SGS and SPG information prescription process. On the other hand, observables in laboratory experiments are always characterized by the finite scales of the instrumental resolution of measuring/visualizing devices, and subject as well to SPG issues. It is thus important to recognize the inherently intrusive nature of observations based on numerical or laboratory experiments. Ultimately, verification and validation (V & V) frameworks and appropriate metrics for the specific problems at hand are needed to establish predictability of the simulation model. Direct numerical simulation (DNS) - resolving all relevant space/time scales, is prohibitively expensive in the foreseeable future for most practical flows of interest at moderate-to-high Reynolds number (Re). On the other end of the simulation spectrum are the Reynolds-Averaged Navier-Stokes (RANS) approaches - which model the turbulent effects. In the coarsegrained large eddy simulation (LES) strategies, the large energy containing structures are resolved, the smaller structures are filtered out, and unresolved SGS effects are modeled. By necessity - rather than choice, LES effectively becomes the intermediate approach between DNS and RANS. Extensive work has demonstrated that predictive simulations of turbulent velocity fields are possible using a particular LES denoted implicit LES (ILES), using the class of nonoscillatory finite-volume (NFV) numerical algorithms. Use of the modified equation as framework for theoretical analysis, demonstrates that leading truncation tenns associated with NFV methods provide implicit SGS models of mixed anisotropic type and regularized motion of discrete observables. Tests in fundamental applications ranging from canonical to very complex flows indicate that ILES is competitive with conventional LES in the LES realm proper - flows driven by large scale features. High-Re flows are vortex dominated and governed by short convective timescales compared to those of diffusion, and kinematically characterized at the smallest scales by slender worm vortices with insignificant internal structure. This motivates nominally inviscid ILES methods capable of capturing the high-Re dissipation dynamics and of handling vortices as shocks in shock capturing schemes. Depending on flow regimes, initial conditions, and resolution, additional modeling may be needed to emulate SGS driven physics, such as backscatter, chemical reaction, material mixing, and near-wall flow-dynamics - where typically-intertwined SGS/SPG issues need to be addressed. A major research focus is recognizing when additional explicit models and/or numerical treatments are needed and ensuring that mixed explicit and implicit SGS models can effectively act in
Weber, N; Priede, J; Stefani, F; Weier, T
2014-01-01T23:59:59.000Z
The Tayler instability is a kink-type flow instability which occurs when the electrical current through a conducting fluid exceeds a certain critical value. Originally studied in the astrophysical context, the instability was recently shown to be also a limiting factor for the upward scalability of liquid metal batteries. In this paper, we continue our efforts to simulate this instability for liquid metals within the framework of an integro-differential equation approach. The original solver is enhanced by multi-domain support with Dirichlet-Neumann partitioning for the static boundaries. Particular focus is laid on the detailed influence of the axial electrical boundary conditions on the characteristic features of the Tayler instability, and, secondly, on the occurrence of electro-vortex flows and their relevance for liquid metal batteries.
M. N. Chernodub; R. Feldmann; E. -M. Ilgenfritz; A. Schiller
2005-02-17T23:59:59.000Z
The confining and topological properties of the compact Abelian Higgs model with doubly-charged Higgs field in three space-time dimensions are studied. We consider the London limit of the model. We show that the monopoles are forming chain-like structures (kept together by ANO vortices) the presence of which is essential for getting simultaneously permanent confinement of singly-charged particles and breaking of the string spanned between doubly-charged particles. In the confinement phase the chains are forming percolating clusters while in the deconfinement (Higgs) phase the chains are of finite size. The described picture is in close analogy with the synthesis of the Abelian monopole and the center vortex pictures in confining non--Abelian gauge models. The screening properties of the vacuum are studied by means of the photon propagator in the Landau gauge.
Stability of flows in fluidized beds
Rajagopal, C.
1992-01-01T23:59:59.000Z
In this paper we carry out a systematic linearized stability analysis of the state of uniform fluidization for a fluid infused with granular particles. We carry out an interesting optimization procedure which leads to bounds for certain parameters, within which the state of uniform fluidization is stable. We find that this stability depends critically on the structure of the pressure-like term. (VC)
Stabilization of Mechanical Systems Using Controlled Lagrangians
Leonard, Naomi
of an inverted pendulum on a cart and for the problem of stabilization of rotation of a rigid spacecraft about grant DMS--91--57556, AFOSR grant F49620961 0100, a GuggenheimFellowship and the Inst. for Advanced. cally provide a Lyapunov function for choosing control gains and proving closedloop stability. Further
Flow stabilization with active hydrodynamic cloaks
Urzhumov, Yaroslav A; 10.1103/PhysRevE.86.056313
2012-01-01T23:59:59.000Z
We demonstrate that fluid flow cloaking solutions based on active hydrodynamic metamaterials exist for two-dimensional flows past a cylinder in a wide range of Reynolds numbers, up to approximately 200. Within the framework of the classical Brinkman equation for homogenized porous flow, we demonstrate using two different methods that such cloaked flows can be dynamically stable for $Re$ in the range 5-119. The first, highly efficient, method is based on a linearization of the Brinkman-Navier-Stokes equation and finding the eigenfrequencies of the least stable eigen-perturbations; the second method is a direct, numerical integration in the time domain. We show that, by suppressing the Karman vortex street in the weekly turbulent wake, porous flow cloaks can raise the critical Reynolds number up to about 120, or five times greater than for a bare, uncloaked cylinder.
Entanglement-assisted codeword stabilized quantum codes
Shin, Jeonghwan; Heo, Jun; Brun, Todd A. [School of Electrical Engineering, Korea University, Seoul (Korea, Republic of); Communication Sciences Institute, University of Southern California, Los Angeles, California 90089 (United States)
2011-12-15T23:59:59.000Z
Entangled qubits can increase the capacity of quantum error-correcting codes based on stabilizer codes. In addition, by using entanglement quantum stabilizer codes can be construct from classical linear codes that do not satisfy the dual-containing constraint. We show that it is possible to construct both additive and nonadditive quantum codes using the codeword stabilized quantum code framework. Nonadditive codes may offer improved performance over the more common stabilizer codes. Like other entanglement-assisted codes, the encoding procedure acts only on the qubits on Alice's side, and only these qubits are assumed to pass through the channel. However, errors in the codeword stabilized quantum code framework give rise to effective Z errors on Bob's side. We use this scheme to construct entanglement-assisted nonadditive quantum codes, in particular, ((5,16,2;1)) and ((7,4,5;4)) codes.
Laser stabilization using spectral hole burning
L. Rippe; B. Julsgaard; A. Walther; S. Kröll
2006-11-05T23:59:59.000Z
We have frequency stabilized a Coherent CR699-21 dye laser to a transient spectral hole on the 606 nm transition in Pr^{+3}:Y_2SiO_5. A frequency stability of 1 kHz has been obtained on the 10 microsecond timescale together with a long-term frequency drift below 1 kHz/s. RF magnetic fields are used to repopulate the hyperfine levels allowing us to control the dynamics of the spectral hole. A detailed theory of the atomic response to laser frequency errors has been developed which allows us to design and optimize the laser stabilization feedback loop, and specifically we give a stability criterion that must be fulfilled in order to obtain very low drift rates. The laser stability is sufficient for performing quantum gate experiments in Pr^{+3}:Y_2SiO_5.
Can the correlated stability conjecture be saved?
Alex Buchel; Alexander Patrushev
2011-06-10T23:59:59.000Z
Correlated stability conjecture (CSC) proposed by Gubser and Mitra [1,2] linked the thermodynamic and classical (in)stabilities of black branes. In [3] it was shown that the thermodynamic instabilities, specifically the negative specific heat, indeed result in the instabilities in the hydrodynamic spectrum of holographically dual plasma excitations. Counter-examples of CSC were presented in the context of black branes with scalar hair undergoing a second-order phase transition [4,5]. The latter translationary invariant horizons have scalar hair, raising the question whether the asymptotic parameters of the scalar hair can be appropriately interpreted as additional charges leading to a generalization of the thermodynamic stability criterion. In this paper we show that the generalization of the thermodynamic stability criterion of this type can not save CSC. We further present a simple statistical model which makes it clear that thermodynamic and dynamical (in)stabilities generically are not correlated.
Structural stability of cooling flows
Henrik Omma; James Binney
2003-12-31T23:59:59.000Z
Three-dimensional hydrodynamical simulations are used to investigate the structural stability of cooling flows that are episodically heated by jets from a central AGN. The radial profile of energy deposition is controlled by (a) the power of the jets, and (b) the pre-outburst density profile. A delay in the ignition of the jets causes more powerful jets to impact on a more centrally concentrated medium. The net effect is a sufficient increase in the central concentration of energy deposition to cause the post-outburst density profile to be less centrally concentrated than that of an identical cluster in which the outburst happened earlier and was weaker. These results suggest that the density profiles of cooling flows oscillate around an attracting profile, thus explaining why cooling flows are observed to have similar density profiles. The possibility is raised that powerful FR II systems are ones in which this feedback mechanism has broken down and a runaway growth of the source parameters has occurred.
Process for stabilization of coal liquid fractions
Davies, Geoffrey (Boston, MA); El-Toukhy, Ahmed (Alexandria, EG)
1987-01-01T23:59:59.000Z
Coal liquid fractions to be used as fuels are stabilized against gum formation and viscosity increases during storage, permitting the fuel to be burned as is, without further expensive treatments to remove gums or gum-forming materials. Stabilization is accomplished by addition of cyclohexanol or other simple inexpensive secondary and tertiary alcohols, secondary and tertiary amines, and ketones to such coal liquids at levels of 5-25% by weight with respect to the coal liquid being treated. Cyclohexanol is a particularly effective and cost-efficient stabilizer. Other stabilizers are isopropanol, diphenylmethanol, tertiary butanol, dipropylamine, triethylamine, diphenylamine, ethylmethylketone, cyclohexanone, methylphenylketone, and benzophenone. Experimental data indicate that stabilization is achieved by breaking hydrogen bonds between phenols in the coal liquid, thereby preventing or retarding oxidative coupling. In addition, it has been found that coal liquid fractions stabilized according to the invention can be mixed with petroleum-derived liquid fuels to produce mixtures in which gum deposition is prevented or reduced relative to similar mixtures not containing stabilizer.
Jacobi stability analysis of the Lorenz system
Tiberiu Harko; Chor Yin Ho; Chun Sing Leung; Stan Yip
2015-04-11T23:59:59.000Z
We perform the study of the stability of the Lorenz system by using the Jacobi stability analysis, or the Kosambi-Cartan-Chern (KCC) theory. The Lorenz model plays an important role for understanding hydrodynamic instabilities and the nature of the turbulence, also representing a non-trivial testing object for studying non-linear effects. The KCC theory represents a powerful mathematical method for the analysis of dynamical systems. In this approach we describe the evolution of the Lorenz system in geometric terms, by considering it as a geodesic in a Finsler space. By associating a non-linear connection and a Berwald type connection, five geometrical invariants are obtained, with the second invariant giving the Jacobi stability of the system. The Jacobi (in)stability is a natural generalization of the (in)stability of the geodesic flow on a differentiable manifold endowed with a metric (Riemannian or Finslerian) to the non-metric setting. In order to apply the KCC theory we reformulate the Lorenz system as a set of two second order non-linear differential equations. The geometric invariants associated to this system (nonlinear and Berwald connections), and the deviation curvature tensor, as well as its eigenvalues, are explicitly obtained. The Jacobi stability of the equilibrium points of the Lorenz system is studied, and the condition of the stability of the equilibrium points is obtained. Finally, we consider the time evolution of the components of the deviation vector near the equilibrium points.
Long life lithium batteries with stabilized electrodes
Amine, Khalil (Downers Grove, IL); Liu, Jun (Naperville, IL); Vissers, Donald R. (Naperville, IL); Lu, Wenquan (Darien, IL)
2009-03-24T23:59:59.000Z
The present invention relates to non-aqueous electrolytes having electrode stabilizing additives, stabilized electrodes, and electrochemical devices containing the same. Thus the present invention provides electrolytes containing an alkali metal salt, a polar aprotic solvent, and an electrode stabilizing additive. In some embodiments the additives include a substituted or unsubstituted cyclic or spirocyclic hydrocarbon containing at least one oxygen atom and at least one alkenyl or alkynyl group. When used in electrochemical devices with, e.g., lithium manganese oxide spinel electrodes or olivine or carbon-coated olivine electrodes, the new electrolytes provide batteries with improved calendar and cycle life.
Towards Understanding the Poor Thermal Stability of V5+ Electrolyte...
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the Poor Thermal Stability of V5+ Electrolyte Solution in Vanadium Redox Flow Batteries. Towards Understanding the Poor Thermal Stability of V5+ Electrolyte Solution in...
attitude stability system: Topics by E-print Network
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
such as Gravity Gradient stabilization, (more) Rawashdeh, Samir Ahmed 2010-01-01 3 Design of Attitude Stability System for Prolate Dual-spin Satellite in Its Inclined...
Enhanced Activity and Stability of Pt catalysts on Functionalized...
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Enhanced Activity and Stability of Pt catalysts on Functionalized Graphene Sheets for Electrocatalytic Oxygen Reduction . Enhanced Activity and Stability of Pt catalysts on...
Electrochemical Performance and Stability of the Cathode for...
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Performance and Stability of the Cathode for Solid Oxide Fuel Cells. I. Cross Validation of Polarization Electrochemical Performance and Stability of the Cathode for Solid Oxide...
Novel Compounds for Enhancing Electrolyte Stability and Safety...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
Compounds for Enhancing Electrolyte Stability and Safety of Lithium-ion Cells Novel Compounds for Enhancing Electrolyte Stability and Safety of Lithium-ion Cells 2010 DOE Vehicle...
Molecular Structure and Stability of Dissolved Lithium Polysulfide...
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Stability of Dissolved Lithium Polysulfide Species. Molecular Structure and Stability of Dissolved Lithium Polysulfide Species. Abstract: Ability to predict the solubility and...
Surface and Structural Stabilities of Carbon Additives in High...
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Structural Stabilities of Carbon Additives in High Voltage Lithium Ion Batteries. Surface and Structural Stabilities of Carbon Additives in High Voltage Lithium Ion Batteries....
Advanced Oxidation & Stabilization of PAN-Based Carbon Precursor...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
More Documents & Publications Advanced Oxidation & Stabilization of PAN-Based Carbon Precursor Fibers Advanced Oxidation & Stabilization of PAN-Based Carbon Precursor...
Composition, stability, and measurement of reduced uranium phases...
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Composition, stability, and measurement of reduced uranium phases for groundwater bioremediation at Old Rifle, CO. Composition, stability, and measurement of reduced uranium phases...
Theoretical Study of the Structure, Stability and Oxygen Reduction...
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Study of the Structure, Stability and Oxygen Reduction Activity ofUltrathin Platinum Nanowires. Theoretical Study of the Structure, Stability and Oxygen Reduction Activity...
Density Functional Study of the Structure, Stability and Oxygen...
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Study of the Structure, Stability and Oxygen Reduction Activity of Ultrathin Platinum Nanowires. Density Functional Study of the Structure, Stability and Oxygen Reduction Activity...
Grain growth and phase stability of nanocrystalline cubic zirconia...
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of nanocrystalline cubic zirconia under ion irradiation. Abstract: Grain growth, oxygen stoichiometry and phase stability of nanostructurally-stabilized zirconia (NSZ) in...
Improved Stability Of Amorphous Zinc Tin Oxide Thin Film Transistors...
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Stability Of Amorphous Zinc Tin Oxide Thin Film Transistors Using Molecular Passivation. Improved Stability Of Amorphous Zinc Tin Oxide Thin Film Transistors Using Molecular...
Stability Of Nanoclusters In 14YWT Oxide Dispersion Strengthened...
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Stability Of Nanoclusters In 14YWT Oxide Dispersion Strengthened Steel Under Heavy Ion-irradiation By Atom Probe Tomography. Stability Of Nanoclusters In 14YWT Oxide Dispersion...
Quality, Stability, Performance, and Emission Impacts of Biodiesel...
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Quality, Stability, Performance, and Emission Impacts of Biodiesel Blends Quality, Stability, Performance, and Emission Impacts of Biodiesel Blends Presentation from the U.S. DOE...
Adaptive Stack with Subdivided Cells for Improved Stability,...
Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site
with Subdivided Cells for Improved Stability, Reliability, and Durability under Automotive Load Cycle Adaptive Stack with Subdivided Cells for Improved Stability, Reliability,...
Mica Surfaces Stabilize Pentavalent Uranium. | EMSL
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Ilton ES, A Haiduc, CL Cahill, and AR Felmy.2005."Mica Surfaces Stabilize Pentavalent Uranium."Inorganic Chemistry 44(9):2986-2988. Authors: ES Ilton A Haiduc CL Cahill AR...
Stability Index of Interaction forms Joseph Abdou
Paris-Sud XI, UniversitÃ© de
Stability Index of Interaction forms Joseph Abdou December 15, 2008 Abstract An interaction form, 106-112 boulevard de l'H^opital 75647 Paris Cedex 13 - France; email: abdou@univ-paris1.fr 1 halshs
LED Color Stability: 10 Important Questions
Broader source: Energy.gov [DOE]
This April 15, 2014 webinar examined the causes of color shift, and took a look at existing metrics used to describe color shift/color stability in LED lighting. The lumen maintenance lifetime of...
Entanglement-assisted codeword stabilized quantum codes
Jeonghwan Shin; Jun Heo; Todd A. Brun
2011-09-15T23:59:59.000Z
Entangled qubit can increase the capacity of quantum error correcting codes based on stabilizer codes. In addition, by using entanglement quantum stabilizer codes can be construct from classical linear codes that do not satisfy the dual-containing constraint. We show that it is possible to construct both additive and non-additive quantum codes using the codeword stabilized quantum code framework. Nonadditive codes may offer improved performance over the more common sta- bilizer codes. Like other entanglement-assisted codes, the encoding procedure acts only the qubits on Alice's side, and only these qubits are assumed to pass through the channel. However, errors the codeword stabilized quantum code framework gives rise to effective Z errors on Bob side. We use this scheme to construct new entanglement-assisted non-additive quantum codes, in particular, ((5,16,2;1)) and ((7,4,5;4)) codes.
What does stabilizing greenhouse gas concentrations mean?
Jacoby, Henry D.; Schmalensee, Richard.; Reiner, David M.
The MIT Emissions Prediction and Policy Analysis (EPPA) model is applied to an exploration of the national emissions obligations that would be required to stabilize atmospheric CO2 concentrations at levels now under active ...
Stabilizer Formalism for Operator Quantum Error Correction
Poulin, D
2005-01-01T23:59:59.000Z
Operator quantum error correction is a recently developed theory that provides a generalized framework for active error correction and passive error avoiding schemes. In this paper, we describe these codes in the language of the stabilizer formalism of standard quantum error correction theory. This is achieved by adding a "gauge" group to the standard stabilizer definition of a code. Gauge transformations leave the encoded information unchanged; their effect is absorbed by virtual gauge qubits that do not carry useful information. We illustrate the construction by identifying a gauge symmetry in Shor's 9-qubit code that allows us to remove 3 of its 8 stabilizer generators, leading to a simpler decoding procedure without affecting its essential properties. This opens the path to possible improvement of the error threshold of fault tolerant quantum computing. We also derive a modified Hamming bound that applies to all stabilizer codes, including degenerate ones.
Static Stability of Tension Leg Platforms
Xu, Ning
2010-07-14T23:59:59.000Z
The static stability of a Tension Leg Platform (TLP) with an intact tendon system is principally provided by its tendons and hence quite different from those of a conventional ship or even a floating structure positioned by its mooring system...
Discontinuous Lyapunov Functions for Nonasymptotic Stability Analysis
Paris-Sud XI, Université de
Discontinuous Lyapunov Functions for Nonasymptotic Stability Analysis A. Polyakov Inria Lille of discontinuous control systems using discontinuous Lyapunov functions. Elements of Filippov theory of generalized derivatives and non-smooth Lyapunov functions are considered. The generalized Lyapunov theorems
Soil stabilization properties of flexible intruders
Luginbuhl, Katharine
2012-01-01T23:59:59.000Z
In many locations, soil is held in place by the roots of plants. When these plants are removed or die, the soil loses its cohesive strength and erodes away. We seek to create artificial soil stabilizers that use the same ...
A model study of articulated mat stability
Sasaki, Tetsu
1990-01-01T23:59:59.000Z
characteristics of. model articulated mat revetrrient svith respect to different revetmert slope con- ditions. In this experirrent three diFierent slope permeabilities were investigated by layering geotextile filter on the revetment frame. The stability... EXPERIMENTAL PROCEDURE 12 18 A. Geotextile filter B. Stability experiment V WAVE RUNUP 18 21 33 VI VII VIII WAVE RUNDOWN UPLIFTING FORCE SLIDE-UP FORCE 44 IX SLIDE-DOWN FORCE 77 SUMMARY AND CONCLUSION REFERENCES . APPENDIX A EXPERIMENTAL...
Electrostatic wire stabilizing a charged particle beam
Prono, D.S.; Caporaso, G.J.; Briggs, R.J.
1983-03-21T23:59:59.000Z
In combination with a charged particle beam generator and accelerator, apparatus and method are provided for stabilizing a beam of electrically charged particles. A guiding means, disposed within the particle beam, has an electric charge induced upon it by the charged particle beam. Because the sign of the electric charge on the guiding means and the sign of the particle beam are opposite, the particles are attracted toward and cluster around the guiding means to thereby stabilize the particle beam as it travels.
Stabilizing windings for tilting and shifting modes
Jardin, Stephen C. (Princeton, NJ); Christensen, Uffe R. (Princeton, NJ)
1984-01-01T23:59:59.000Z
This invention relates to passive conducting loops for stabilizing a plasma ring against unstable tilting and/or shifting modes. To this end, for example, plasma ring in a spheromak is stabilized by a set of four figure-8 shaped loops having one pair on one side of the plasma and one pair on the other side with each pair comprising two loops whose axes are transverse to each other.
Engineering report (conceptual design) PFP solution stabilization
Witt, J.B.
1997-07-17T23:59:59.000Z
This Engineering Report (Conceptual Design) addresses remediation of the plutonium-bearing solutions currently in inventory at the Plutonium Finishing Plant (PFP). The recommendation from the Environmental Impact Statement (EIS) is that the solutions be treated thermally and stabilized as a solid for long term storage. For solutions which are not discardable, the baseline plan is to utilize a denitration process to stabilize the solutions prior to packaging for storage.
Stabilized fuel with silica support structure
Poco, J.F.; Hrubesh, L.W.
1991-12-31T23:59:59.000Z
This report describes a stabilized fuel which is supported by a silica support structure. The silica support structure provides a low density, high porosity vehicle for safely carrying hydrocarbon fuels. The silica support structure for hydrocarbon fuel does not produce toxic material residues on combustion which would pose environmentally sensitive disposal problems. The silica stabilized fuel composition is useful as a low temperature, continuous burning fire starter for wood or charcoal.
Vortex structures and zero-energy states in the BCS-to-BEC evolution of p-wave resonant Fermi gases
Mizushima, T.; Machida, K. [Department of Physics, Okayama University, Okayama 700-8530 (Japan)
2010-05-15T23:59:59.000Z
Multiply quantized vortices in the BCS-to-BEC (Bose-Einstein condensation) evolution of p-wave resonant Fermi gases are investigated theoretically. The vortex structure and the low-energy quasiparticle states are discussed, based on the self-consistent calculations of the Bogoliubov-de Gennes and gap equations. We reveal the direct relation between the macroscopic structure of vortices, such as particle densities, and the low-lying quasiparticle state. In addition, the net angular momentum for multiply quantized vortices with a vorticity {kappa} is found to be expressed by a simple equation, which reflects the chirality of the Cooper pairing. Hence, the observation of the particle density depletion and the measurement of the angular momentum will provide the information on the core-bound state and p-wave superfluidity. Moreover, the details on the zero energy Majorana state are discussed in the vicinity of the BCS-to-BEC evolution. It is demonstrated numerically that the zero energy Majorana state appears in the weak coupling BCS limit only when the vortex winding number is odd. The {kappa} branches of the core-bound states for a vortex state with vorticity {kappa} exist; however, only one of them can be the zero energy. This zero energy state vanishes at the BCS-BEC topological phase transition because of interference between the core-bound and edge-bound states.
Jammazi, Chaker [Faculte des Sciences de Bizerte Departement de Mathematiques Laboratoire LIM Ecole Polytechnique de Tunisie (Tunisia)
2009-03-05T23:59:59.000Z
The paper gives Lyapunov type sufficient conditions for partial finite-time and asymptotic stability in which some state variables converge to zero while the rest converge to constant values that possibly depend on the initial conditions. The paper then presents partially asymptotically stabilizing controllers for many nonlinear control systems for which continuous asymptotically stabilizing (in the usual sense) controllers are known not to exist.
Sundman Stability of Natural Planet Satellites
Lukyanov, L G
2012-01-01T23:59:59.000Z
The stability of the motion of the planet satellites is considered in the model of the general three-body problem (Sun-planet-satellite). "Sundman surfaces" are constructed, by means of which the concept "Sundman stability" is formulated. The comparison of the Sundman stability with the results of Golubev's c2h method and with the Hill's classical stability in the restricted three-body problem is performed. The constructed Sundman stability regions in the plane of the parameters "energy - moment of momentum" coincide with the analogous regions obtained by Golubev's method, with the value (c2h)cr. The construction of the Sundman surfaces in the three-dimensional space of the specially selected coordinates xyR is carried out by means of the exact Sundman inequality in the general three-body problem. The determination of the singular points of surfaces, the regions of the possible motion and Sundman stability analysis are implemented. It is shown that the singular points of the Sundman surfaces in the coordinate...
MERCURY STABILITY IN THE ENVIRONMENT
John H. Pavlish
1999-07-01T23:59:59.000Z
The 1990 Clean Air Act Amendments (CAAAs) require the U.S. Environmental Protection Agency (EPA) to determine whether the presence of mercury and 188 other trace substances, referred to as air toxics or hazardous air pollutants (HAPs), in the stack emissions from fossil fuel-fired electric utility power plants poses an unacceptable public health risk (1). The EPA's conclusions and recommendations were presented in two reports: Mercury Study Report to Congress and Study of Hazardous Air Pollutant Emissions from Electric Utility Steam Generating Units-Final Report to Congress. The first congressional report addressed both human health and the environmental effects of anthropogenic mercury emissions, while the second report addressed the risk to public health posed by emissions of HAPs from steam electricity-generating units. The National Institute of Environmental Health Sciences is also required by the CAAAs to investigate mercury and determine a safe threshold level of exposure. Recently the National Academy of Sciences has also been commissioned by Congress to complete a report, based the available scientific evidence, regarding safe threshold levels of mercury exposure. Although the EPA reports did not state that mercury controls on coal-fired electric power stations should be required given the current state of the art, they did indicate that EPA views mercury as a potential threat to human health. It is likely that major sources of mercury emissions, including fossil-fired combustion systems, will be controlled at some point. In fact, municipal waste combustion units are already regulated. In anticipation of additional control measures, much research has been done (and continues) regarding the development of control technologies for mercury emitted from stationary sources to the atmosphere. Most approaches taken to date involve sorbent injection technologies or improve upon removal of mercury using existing technologies such as flue gas desulfurization scrubbers, fabric filters, and electrostatic precipitators. Depending on the fly ash chemistry and the form of mercury present in the flue gas, some of these existing technologies can be effective at capturing vapor-phase mercury from the flue gas stream. Although much research has been done on enhancing the removal of mercury from flue gas streams, little research has focused on what happens to the mercury when it is captured and converted and/or transferred to a solid or aqueous solution. The stability (or mobility) of mercury in this final process is critical and leads to the questions, What impact will the increased concentration of mercury have on utilization, disposal, and reuse? and Is the mercury removed from the flue gas really removed from the environment or rereleased at a later point? To help answer these questions, the Energy & Environmental Research Center (EERC) as part of the U.S. Department of Energy (DOE) Base Cooperative Agreement did a series of experiments using thermal desorption and leaching techniques. This report presents the results from these tests.
Explosive magnetic reconnection caused by an X-shaped current-vortex layer in a collisionless plasma
Hirota, Makoto; Morrison, Philip J
2015-01-01T23:59:59.000Z
A mechanism for explosive magnetic reconnection is investigated by analyzing the nonlinear evolution of a collisionless tearing mode in a two-fluid model that includes the effects of electron inertia and temperature. These effects cooperatively enable a fast reconnection by forming an X-shaped current-vortex layer centered at the reconnection point. A high-resolution simulation of this model for an unprecedentedly small electron skin depth $d_e$ and ion-sound gyroradius $\\rho_s$, satisfying $d_e=\\rho_s$, shows an explosive tendency for nonlinear growth of the tearing mode, where it is newly found that the explosive widening of the X-shaped layer occurs locally around the reconnection point with the length of the X shape being shorter than the domain length and the wavelength of the linear tearing mode. The reason for the onset of this locally enhanced reconnection is explained theoretically by developing a novel nonlinear and nonequilibrium inner solution that models the local X-shaped layer, and then matchin...
Stability and feasibility of state-constrained linear MPC without stabilizing terminal constraints
Knobloch,JÃ¼rgen
, an optimal control problem. In this paper we study stability and recursive feasibility of linear MPC schemes] stability and recursive feasibility is shown for controllable linear quadratic systems with mixed linear and control constraints. Stabilizable linear systems are also considered in [18] but in an uncon- strained
Bronfenbrenner, James C. (Allentown, PA); Foster, Edward P. (Allentown, PA); Tewari, Krishna (Allentown, PA)
1985-01-01T23:59:59.000Z
A process is disclosed for stabilizing the viscosity of coal derived materials such as an SRC product by adding up to 5.0% by weight of a light volatile phenolic viscosity repressor. The viscosity will remain stabilized for a period of time of up to 4 months.
The (In)Stability of Planetary Systems
Rory Barnes; Thomas Quinn
2004-01-09T23:59:59.000Z
We present results of numerical simulations which examine the dynamical stability of known planetary systems, a star with two or more planets. First we vary the initial conditions of each system based on observational data. We then determine regions of phase space which produce stable planetary configurations. For each system we perform 1000 ~1 million year integrations. We examine upsilon And, HD83443, GJ876, HD82943, 47UMa, HD168443, and the solar system (SS). We find that the resonant systems, 2 planets in a first order mean motion resonance, (HD82943 and GJ876) have very narrow zones of stability. The interacting systems, not in first order resonance, but able to perturb each other (upsilon And, 47UMa, and SS) have broad regions of stability. The separated systems, 2 planets beyond 10:1 resonance, (we only examine HD83443 and HD168443) are fully stable. Furthermore we find that the best fits to the interacting and resonant systems place them very close to unstable regions. The boundary in phase space between stability and instability depends strongly on the eccentricities, and (if applicable) the proximity of the system to perfect resonance. In addition to million year integrations, we also examined stability on ~100 million year timescales. For each system we ran ~10 long term simulations, and find that the Keplerian fits to these systems all contain configurations which may be regular on this timescale.
Stability Study of the RERTR Fuel Microstructure
Jian Gan; Dennis Keiser; Brandon Miller; Daniel Wachs
2014-04-01T23:59:59.000Z
The irradiation stability of the interaction phases at the interface of fuel and Al alloy matrix as well as the stability of the fission gas bubble superlattice is believed to be very important to the U-Mo fuel performance. In this paper the recent result from TEM characterization of Kr ion irradiated U-10Mo-5Zr alloy will be discussed. The focus will be on the phase stability of Mo2-Zr, a dominated second phase developed at the interface of U-10Mo and the Zr barrier in a monolithic fuel plate from fuel fabrication. The Kr ion irradiations were conducted at a temperature of 200 degrees C to an ion fluence of 2.0E+16 ions/cm2. To investigate the thermal stability of the fission gas bubble superlattice, a key microstructural feature in both irradiated dispersion U-7Mo fuel and monolithic U-10Mo fuel, a FIB-TEM sample of the irradiated U-10Mo fuel (3.53E+21 fission/cm3) was used for a TEM in-situ heating experiment. The preliminary result showed extraordinary thermal stability of the fission gas bubble superlattice. The implication of the TEM observation from these two experiments on the fuel microstructural evolution under irradiation will be discussed.
Vacuum (meta)stability beyond the MSSM
Blum, Kfir; Delaunay, Cedric; Hochberg, Yonit [Department of Particle Physics, Weizmann Institute of Science, Rehovot 76100 (Israel)
2009-10-01T23:59:59.000Z
We study the stability of the Higgs potential in the framework of the effective Lagrangian beyond the minimal supersymmetric standard model (MSSM). While the leading nonrenormalizable operators can shift the Higgs boson mass above the experimental bound, they also tend to render the scalar potential unbounded from below. The destabilization is correlated with the Higgs mass increase, so that if quantum corrections are small the problem is severe. We show that a supersymmetric subleading correction stabilizes the potential within the domain of validity of the effective theory. Constraints on MSSM parameters as well as on higher dimensional operators are derived, ensuring that our vacuum has a lifetime longer than the present age of the Universe. In addition we show that when effective operators are responsible for evading the LEP bound, stability constraints imply an upper bound on the scale of new physics in the few TeV range.
Sensitivity approximation for robust stability and tracking
McLean, Chris Steven
1984-01-01T23:59:59.000Z
(s) such that the Bezout identity is satisfied a(s) s(s) + d(s) &(s) = 1. In the single loop control configuration of Figure 1, the set of all proper stabilizing compensators is of the form &( ) + a(s)k(s) C(s) = z(s) ? b(s) k(s) ' where k(s) is any stable, proper... whether or not a stable proper k(s) exists such that the following is an equality, Ss(s) = a(s)jz(s) ? b(s)k(s)j. (i4) Obviously the properties of causality and stability that k(s) must satisfy to ensure internal stability translate into constraints...
Wind Power Plant Voltage Stability Evaluation: Preprint
Muljadi, E.; Zhang, Y. C.
2014-09-01T23:59:59.000Z
Voltage stability refers to the ability of a power system to maintain steady voltages at all buses in the system after being subjected to a disturbance from a given initial operating condition. Voltage stability depends on a power system's ability to maintain and/or restore equilibrium between load demand and supply. Instability that may result occurs in the form of a progressive fall or rise of voltages of some buses. Possible outcomes of voltage instability are the loss of load in an area or tripped transmission lines and other elements by their protective systems, which may lead to cascading outages. The loss of synchronism of some generators may result from these outages or from operating conditions that violate a synchronous generator's field current limit, or in the case of variable speed wind turbine generator, the current limits of power switches. This paper investigates the impact of wind power plants on power system voltage stability by using synchrophasor measurements.
Stabilizer Formalism for Operator Quantum Error Correction
David Poulin
2006-06-14T23:59:59.000Z
Operator quantum error correction is a recently developed theory that provides a generalized framework for active error correction and passive error avoiding schemes. In this paper, we describe these codes in the stabilizer formalism of standard quantum error correction theory. This is achieved by adding a "gauge" group to the standard stabilizer definition of a code that defines an equivalence class between encoded states. Gauge transformations leave the encoded information unchanged; their effect is absorbed by virtual gauge qubits that do not carry useful information. We illustrate the construction by identifying a gauge symmetry in Shor's 9-qubit code that allows us to remove 4 of its 8 stabilizer generators, leading to a simpler decoding procedure and a wider class of logical operations without affecting its essential properties. This opens the path to possible improvements of the error threshold of fault-tolerant quantum computing.
Quantum Stabilizer Codes Embedding Qubits Into Qudits
Carlo Cafaro; Federico Maiolini; Stefano Mancini
2012-07-30T23:59:59.000Z
We study, by means of the stabilizer formalism, a quantum error correcting code which is alternative to the standard block codes since it embeds a qubit into a qudit. The code exploits the non-commutative geometry of discrete phase space to protect the qubit against both amplitude and phase errors. The performance of such code is evaluated on Weyl channels by means of the entanglement fidelity as function of the error probability. A comparison with standard block codes, like five and seven qubit stabilizer codes, shows its superiority.
Stability of the Trotter-Suzuki decomposition
Ish Dhand; Barry C. Sanders
2014-07-09T23:59:59.000Z
The Trotter-Suzuki decomposition is an important tool for the simulation and control of physical systems. We provide evidence for the stability of the Trotter-Suzuki decomposition. We model the error in the decomposition and determine sufficiency conditions that guarantee the stability of this decomposition under this model. We relate these sufficiency conditions to precision limitations of computing and control in both classical and quantum cases. Furthermore we show that bounded-error Trotter-Suzuki decomposition can be achieved by a suitable choice of machine precision.
Mercury stabilization in chemically bonded phosphate ceramics
Wagh, A. S.; Singh, D.; Jeong, S. Y.
2000-04-04T23:59:59.000Z
Mercury stabilization and solidification is a significant challenge for conventional stabilization technologies. This is because of the stringent regulatory limits on leaching of its stabilized products. In a conventional cement stabilization process, Hg is converted at high pH to its hydroxide, which is not a very insoluble compound; hence the preferred route for Hg sulfidation to convert it into insoluble cinnabar (HgS). Unfortunately, efficient formation of this compound is pH-dependent. At a high pH, one obtains a more soluble Hg sulfate, in a very low pH range, insufficient immobilization occurs because of the escape of hydrogen sulfide, while efficient formation of HgS occurs only in a moderately acidic region. Thus, the pH range of 4 to 8 is where stabilization with Chemically Bonded Phosphate Ceramics (CBPC) is carried out. This paper discusses the authors experience on bench-scale stabilization of various US Department of Energy (DOE) waste streams containing Hg in the CBPC process. This process was developed to treat DOE's mixed waste streams. It is a room-temperature-setting process based on an acid-base reaction between magnesium oxide and monopotassium phosphate solution that forms a dense ceramic within hours. For Hg stabilization, addition of a small amount (< 1 wt.%) of Na{sub 2}S or K{sub 2}S is sufficient in the binder composition. Here the Toxicity Characteristic Leaching Procedure (TCLP) results on CBPC waste forms of surrogate waste streams representing secondary Hg containing wastes such as combustion residues and Delphi DETOX{trademark} residues are presented. The results show that although the current limit on leaching of Hg is 0.2 mg/L, the results from the CBPC waste forms are at least one order lower than this stringent limit. Encouraged by these results on surrogate wastes, they treated actual low-level Hg-containing mixed waste from their facility at Idaho. TCLP results on this waste are presented here. The efficient stabilization in all these cases is attributed to chemical immobilization as both a sulfide (cinnabar) and a phosphate, followed by its physical encapsulation in a dense matrix of the ceramic.
Fluid sphere: stability problem and dimensional constraint
Farook Rahaman; Anirudh Pradhan; Nasr Ahmed; Saibal Ray; Bijan Saha; Mosiur Rahaman
2015-04-14T23:59:59.000Z
We study different dimensional fluids inspired by noncommutative geometry which admit conformal Killing vectors. The solutions of the Einstein field equations examined specifically for five different set of spacetime. We calculate the active gravitational mass and impose stability conditions of the fluid sphere. The analysis thus carried out immediately indicates that at $4$-dimension only one can get a stable configuration for any spherically symmetric stellar system and any other dimensions, lower or higher, becomes untenable as far as the stability of a system is concerned.
Renewable source controls for grid stability.
Byrne, Raymond Harry; Elliott, Ryan Thomas; Neely, Jason C.; Silva Monroy, Cesar Augusto; Schoenwald, David Alan; Grant, Lisa
2012-12-01T23:59:59.000Z
The goal of this study was to evaluate the small signal and transient stability of the Western Electric- ity Coordinating Council (WECC) under high penetrations of renewable energy, and to identify control technologies that would improve the system performance. The WECC is the regional entity responsible for coordinating and promoting bulk electric system reliability in the Western Interconnection. Transient stability is the ability of the power system to maintain synchronism after a large disturbance while small signal stability is the ability of the power system to maintain synchronism after a small disturbance. Tran- sient stability analysis usually focuses on the relative rotor angle between synchronous machines compared to some stability margin. For this study we employed generator speed relative to system speed as a metric for assessing transient stability. In addition, we evaluated the system transient response using the system frequency nadir, which provides an assessment of the adequacy of the primary frequency control reserves. Small signal stability analysis typically identi es the eigenvalues or modes of the system in response to a disturbance. For this study we developed mode shape maps for the di erent scenarios. Prony analysis was applied to generator speed after a 1.4 GW, 0.5 second, brake insertion at various locations. Six di erent WECC base cases were analyzed, including the 2022 light spring case which meets the renewable portfolio standards. Because of the di culty in identifying the cause and e ect relationship in large power system models with di erent scenarios, several simulations were run on a 7-bus, 5-generator system to isolate the e ects of di erent con gurations. Based on the results of the study, for a large power system like the WECC, incorporating frequency droop into wind/solar systems provides a larger bene t to system transient response than replacing the lost inertia with synthetic inertia. From a small signal stability perspective, the increase in renewable penetration results in subtle changes to the system modes. In gen- eral, mode frequencies increase slightly, and mode shapes remain similar. The system frequency nadir for the 2022 light spring case was slightly lower than the other cases, largely because of the reduced system inertia. However, the nadir is still well above the minimum load shedding frequency of 59.5 Hz. Finally, several discrepancies were identi ed between actual and reported wind penetration, and additional work on wind/solar modeling is required to increase the delity of the WECC models.
Turbine Objective Francis turbines working in off design operating conditions may experience the formation the stability of the machine operation, since it is a major source of pressure fluctuation in the hydraulic of the draft tube on a reduce scale model of a Francis turbine operating at full load. In particular
Large-Scale Synthesis of Lipid-Polymer Hybrid Nanoparticles Using a Multi-Inlet Vortex Reactor
Zhang, Liangfang
polymeric core for the efficient loading of poorly water-soluble drugs; a lipid monolayer surrounding the core that enhances the particle's stability in salt solutions and helps to reduce outward diffusion of drug; and a lipid-PEG outer corona that protects the particle from the immune system in vivo
Manohar S. Sohal
2005-09-01T23:59:59.000Z
This report summarizes work at the Idaho National Laboratory to develop strategies to enhance air-side heat transfer in geothermal air-cooled condensers such that it should not significantly increase pressure drop and parasitic fan pumping power. The work was sponsored by the U.S. Department of Energy, NEDO (New Energy and Industrial Technology Development Organization) of Japan, Yokohama National University, and the Indian Institute of Technology, Kanpur, India. A combined experimental and numerical investigation was performed to investigate heat transfer enhancement techniques that may be applicable to largescale air-cooled condensers such as those used in geothermal power applications. A transient heat transfer visualization and measurement technique was employed in order to obtain detailed distributions of local heat transfer coefficients on model fin surfaces. Pressure drop measurements were obtained for a variety of tube and winglet configurations using a single-channel flow apparatus that included four tube rows in a staggered array. Heat transfer and pressure drop measurements were also acquired in a separate multiple-tube row apparatus in the Single Blow Test Facility. In addition, a numerical modeling technique was developed to predict local and average heat transfer for these low-Reynolds number flows, with and without winglets. Representative experimental and numerical results were obtained that reveal quantitative details of local finsurface heat transfer in the vicinity of a circular tube with a single delta winglet pair downstream of the cylinder. Heat transfer and pressure-drop results were obtained for flow Reynolds numbers based on channel height and mean flow velocity ranging from 700 to 6500. The winglets were of triangular (delta) shape with a 1:2 or 1:3 height/length aspect ratio and a height equal to 90% of the channel height. Overall mean fin-surface heat transfer results indicate a significant level of heat transfer enhancement (in terms of Colburn j-factor) associated with deployment of the winglets with circular as well as oval tubes. In general, toe-in (common flow up) type winglets appear to have better performance than the toe-out (common flow down) type winglets. Comparisons of heat transfer and pressure drop results for the elliptical tube versus a circular tube with and without winglets are provided. During the course of their independent research, all of the researchers have established that about 10 to 30% enhancement in Colburn j-factor is expected. However, actual increase in heat transfer rate from a heat exchanger employing finned tubes with winglets may be smaller, perhaps on the order of 2 to 5%. It is also concluded that for any specific application, more full-size experimentation is needed to optimize the winglet design for a specific heat exchanger application. If in place of a circular tube, an oval tube can be economically used in a bundle, it is expected that the pressure drop across the tube bundle with the application of vortex generators (winglets) will be similar to that in a conventional circular tube bundle. It is hoped that the results of this research will demonstrate the benefits of applying vortex generators (winglets) on the fins to improve the heat transfer from the air-side of the tube bundle.
Compass Financial Stability and Savings Program
Fraden, Seth
Compass Financial Stability and Savings Program Pilot Evaluation: Second Year Report April 2013 Prepared for Compass Working Capital Boston, MA Prepared by Delia Kimbrel, Research Associate Institute, MA #12;Compass Working Capital Compass Working Capital ("Compass") provides incentive-based financial
Compass Financial Stability and Savings Program
Fraden, Seth
Compass Financial Stability and Savings Program Pilot Evaluation: Final Report 1 April 2014 Prepared for Compass Working Capital Boston, MA Prepared by Delia Kimbrel, Research Associate Sandra Venner Brandeis University, Waltham, MA #12;2 Compass Working Capital ("Compass") provides incentive
A Stability Index for Local Effectivity Functions
Paris-Sud XI, UniversitÃ© de
A Stability Index for Local Effectivity Functions Joseph Abdou October 9, 2009 Abstract We study - France; email: abdou@univ-paris1.fr 1 halshs-00389003,version1-14Oct2009 Author manuscript, published setting (see Abdou and Keiding (2003) for the general notion of effectiv- ity structure), we shall focus
A DOUBLY STABILIZED BUNDLE METHOD FOR NONSMOOTH ...
2013-04-13T23:59:59.000Z
Apr 13, 2013 ... As is widely accepted, the most efficient optimization techniques ... (ii) a stability center xk (some previous iterate, usually the “best” point generated by the iterative .... unit-commitment problem in the energy sector, two-stage stochastic linear programming, and ..... data, the case analyzed in Section 4 below.
Power Systems Stability Control : Reinforcement Learning Framework
Wehenkel, Louis
1 Power Systems Stability Control : Reinforcement Learning Framework Damien Ernst, Member, IEEE systems. We describe some challenges in power system control and discuss how some of those challenges with the real power system and the off-line mode in which the interaction occurs with a simulation model
The effect of convection on pulsational stability
G. Houdek
2008-10-29T23:59:59.000Z
A review on the current state of mode physics in classical pulsators is presented. Two, currently in use, time-dependent convection models are compared and their applications on mode stability are discussed with particular emphasis on the location of the Delta Scuti instability strip.
Threedimensional stability of Burgers vortices Thierry Gallay
Gallay, Thierry
ThreeÂdimensional stability of Burgers vortices Thierry Gallay Institut Fourier Universitâ??e de Grenoble I BP 74 38402 SaintÂMartinÂd'Hâ??eres, France Thierry.Gallay@ujfÂgrenoble.fr Yasunori Maekawa and then in the general case by Gallay and Wayne [9], see also [2, 12, 13]. Moreover, a lot is known about the spectrum
Metal Nanowires: Quantum Transport, Cohesion, and Stability
Stafford, Charles
nature's ultimate limit of conductors down to a single atom in thickness. In the past eight years. In this article, we discuss our generalization of the free-electron model to describe nanoscale conductors [15 to surface tension [23], but we find that electron-shell effects can stabilize arbitrarily long nanowires [22
PID Controller Synthesis with Specified Stability Requirement
Gundes, A. N.
PID Controller Synthesis with Specified Stability Requirement for Some Classes of MIMO Systems T. S+Integral+Derivative (PID) con- trollers, where the closed-loop poles can be assigned to the left of an axis shifted PID-controllers with this property of small negative real-part assignability of closed-loop poles
Amphiphiles for protein solubilization and stabilization
Gellman, Samuel Helmer; Chae, Pil Seok; Laible, Philip D.; Wander, Marc J.
2012-09-11T23:59:59.000Z
The invention provides amphiphiles for manipulating membrane proteins. The amphiphiles can feature carbohydrate-derived hydrophilic groups and branchpoints in the hydrophilic moiety and/or in a lipophilic moiety. Such amphiphiles are useful as detergents for solubilization and stabilization of membrane proteins, including photosynthetic protein superassemblies obtained from bacterial membranes.
http://www.pppl.gov Stabilization
Zakharov, Leonid E.
MHD. 2. Flow pattern of magnetic propulsion. 3. Theory of stabilization. 4. Flow locked mode. 5 of magnetic propulsion (cont.) Magnetic propulsion makes MHD of intense lithium streams compatible 8 #12; 2 Flow pattern of magnetic propulsion (cont.) Driving pressure pwall j outlet > 1 atm; p wall
Agent Based Power System Transient Stability Enhancement
Pota, Himanshu Roy
Agent Based Power System Transient Stability Enhancement M. S. Rahman, Student Member, IEEE, M. J. Hossain and H. R. Pota Abstract--This paper describes an intelligent agent approach to power system fault electric power system is most capital investive and vast complex network with increasing interconnections
Stabilization of Mechanical Systems Using Controlled Lagrangians
Marsden, Jerrold
for the problem of sta- bilization of an inverted pendulum on a cart and for the problem of stabilization9157556, AFOSR grant F49620-96-1- 0100, a Guggenheim Fellowship and the Inst. for Advanced Study. 2 can make use of energy methods which automati- cally provide a Lyapunov function for choosing control
Stability, Energetics, and Turbulent Transport in
Torquato, Salvatore
fields" Department of Astrophysical Sciences Spring Colloquium Steve Cowley (UK Atomic Energy Authority of solar-wind turbulence" Chris Chen (UC Berkeley) 2:40pm "Energy spectra in MHD turbulenceStability, Energetics, and Turbulent Transport in Astrophysical, Fusion, and Solar Plasmas 8
Sulfate induced heave in lime stabilized soil
Bredenkamp, Sanet
1994-01-01T23:59:59.000Z
The addition of hydrated lime to clay soils is one of the most common methods of soil stabilization. However, when sulfates are present in the soil, the calcium in the lime reacts with the sulfates to form ettringite, an expandable mineral...
PLUTONIUM FINISHING PLANT (PFP) STABILIZATION & PACKAGING PROJECT
GERBER, M.S.
2004-01-14T23:59:59.000Z
Fluor Hanford is pleased to submit the Plutonium Finishing Plant (PFP) Stabilization and Packaging Project (SPP) for consideration by the Project Management Institute as Project of the Year for 2004. The SPP thermally stabilized and/or packaged nearly 18 metric tons (MT) of plutonium and plutonium-bearing materials left in PFP facilities from 40 years of nuclear weapons production and experimentation. The stabilization of the plutonium-bearing materials substantially reduced the radiological risk to the environment and security concerns regarding the potential for terrorists to acquire the non-stabilized plutonium products for nefarious purposes. The work was done In older facilities which were never designed for the long-term storage of plutonium, and required working with materials that were extremely radioactive, hazardous, pyrophoric, and In some cases completely unique. I n some Instances, one-of-a-kind processes and equipment were designed, installed, and started up. The SPP was completed ahead of schedule, substantially beating all Interim progress milestone dates set by the Defense Nuclear Facilities Safety Board (DNFSB) and in the Hanford Site's Federal Facility Agreement and Consent Order (Tri-Party Agreement or TPA), and finished $1-million under budget.
Lateral stability of long precast concrete beams
Burgoyne, Chris
buckling L length of beam vx lateral de¯ection measured in the minor- axis direction (which rotates with yLateral stability of long precast concrete beams T. J. Stratford, BA, BEng, and C. J. Burgoyne, BA, making them more susceptible to buckling failure. This paper shows that once the beam is positioned
ROCTECtm STABILIZATION TREATMENT OF WERF ASH
Paul A. Lessing; William J. Quapp; Gary Renlund; Bob Clark; Colin Hundley; James Cornwell; Dave Schlier; John Bulko; Gene Pollack
1998-10-01T23:59:59.000Z
The objective of this project is to demonstrate a process to stabilize mixed waste flyash generated by the combustion of mixed waste at the Idaho National Engineering & Environmental Laboratory's (INEEL's) Waste Experimental Reduction Facility (WERF) incinerator such that it will meet Resource Conservation and Recovery Act (RCRA) Land Disposal Restrictions (LDRs) Universal Treatment Standards.
Safety evaluation of interim stabilization of non-stabilized single-shell watch list tanks
Stahl, S.M.
1994-12-30T23:59:59.000Z
The report provides a summation of the status of safety issues associated with interim stabilization of Watch List SSTs (organic, ferrocyanide, and flammable gas), as extracted from recent safety analyses, including the Tank Farms Accelerated Safety Analysis efforts.
Sufficient Conditions for Uniform Stability of Regularization Algorithms
Poggio, Tomaso
2009-12-01T23:59:59.000Z
In this paper, we study the stability and generalization properties of penalized empirical-risk minimization algorithms. We propose a set of properties of the penalty term that is sufficient to ensure uniform ?-stability: ...
Relation between viscosity and stability for heavy oil emulsions
Ye, Sherry Qianwen
1998-01-01T23:59:59.000Z
The relation between viscosity and stability has been hics. found by investigating the effect of surfactant concentration on emulsion stability. Based on the Bingham plastic model for viscosity as a function of shear rate, two parameters were found...
Title of dissertation: MAGNETOHYDRODYNAMIC EQUILIBRIUM AND STABILITY OF
Anlage, Steven
ABSTRACT Title of dissertation: MAGNETOHYDRODYNAMIC EQUILIBRIUM AND STABILITY OF CENTRIFUGALLY CONFINED PLASMAS Yi-Min Huang, Doctor of Philosophy, 2004 Dissertation directed by: Professor Adil B. This dissertation addresses the equilib- rium and stability of this configuration within the framework
Electronic Structure and Stability of Semiconducting Graphene Nanoribbons
Hod, Oded
Electronic Structure and Stability of Semiconducting Graphene Nanoribbons Vero´nica Barone, Oded stability of semiconducting graphene nanoribbons. We consider ribbons with different edge nature including band structure of graphene (a single infinite sheet of graphite). Depending on their chirality
Upper bounds on minimum distance of nonbinary quantum stabilizer codes
Kumar, Santosh
2005-11-01T23:59:59.000Z
The most popular class of quantum error correcting codes is stabilizer codes. Binary quantum stabilizer codes have been well studied, and Calderbank, Rains, Shor and Sloane (July 1998) have constructed a table of upper bounds on the minimum distance...
Effects of additives on the stability of electrolytes for all...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Effects of additives on the stability of electrolytes for all-vanadium redox flow batteries. Effects of additives on the stability of electrolytes for all-vanadium redox flow...
The Stability of Organic Solvents and Carbon Electrode in Nonaqueous...
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
The Stability of Organic Solvents and Carbon Electrode in Nonaqueous Li-O2 Batteries. The Stability of Organic Solvents and Carbon Electrode in Nonaqueous Li-O2 Batteries....
Stability of Biomass-derived Black Carbon in Soils . | EMSL
Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)
Stability of Biomass-derived Black Carbon in Soils . Stability of Biomass-derived Black Carbon in Soils . Abstract: Black carbon (BC) may play an important role in the global C...
Fourier-Mukai transforms and stability conditions on abelian threefolds
Piyaratne, Hathurusinghege Dulip Bandara
2014-11-27T23:59:59.000Z
Construction of Bridgeland stability conditions on a given Calabi-Yau threefold is an important problem and this thesis realizes the rst known examples of such stability conditions. More precisely, we construct a dense ...
Stability of Biodiesel and Biodiesel Blends: Interim Report
McCormick, R. L.; Alleman, T. L.; Waynick, J. A.; Westbrook, S. R.; Porter, S.
2006-04-01T23:59:59.000Z
This is an interim report for a study of biodiesel oxidative stability. It describes characterization and accelerated stability test results for 19 B100 samples and six diesel fuels.
Stabilized finite element methods with fast iterative solution ...
2003-04-11T23:59:59.000Z
Computer methods in applied mechanics and engineering. Stabilized finite ... Department of Mathemutics, Purdue Universi@, 1395 Mathematical Science ...