National Library of Energy BETA

Sample records for vortex stabilizer pneumatic

  1. -STABILITY AND VORTEX MOTION IN TYPE II SUPERCONDUCTORS

    E-Print Network [OSTI]

    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

  2. Vortex stabilized electron beam compressed fusion grade plasma

    SciTech Connect (OSTI)

    Hershcovitch, Ady

    2014-03-19

    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.

  3. Stabilization of three-wave vortex beams in the waveguide

    E-Print Network [OSTI]

    Gammal, Arnaldo

    2015-01-01

    We consider two-dimensional (2D) localized vortical modes in the three-wave system with the quadratic ($\\chi ^{(2)}$) nonlinearity, alias nondegenerate second-harmonic-generating system, guided by the isotropic harmonic-oscillator (HO) (alias parabolic) confining potential. In addition to the straightforward realization in optics, the system models mixed atomic-molecular Bose-Einstein condensates (BECs). The main issue is stability of the vortex modes, which is investigated through computation of instability growth rates for eigenmodes of small perturbations, and by means of direct simulations. The threshold of parametric instability for single-color beams, represented solely by the second harmonic (SH) with zero vorticity, is found in an analytical form with the help of the variational approximation (VA). Trapped states with vorticities $\\left( +1,-1,0\\right) $ in the two fundamental-frequency (FF) components and the SH one [the so-called \\textit{hidden-vorticity} (HV) modes] are completely unstable. Also un...

  4. Super Stability of Laminar Vortex Flow in Superfluid 3He-B

    E-Print Network [OSTI]

    V. B. Eltsov; R. de Graaf; P. J. Heikkinen; J. J. Hosio; R. Hanninen; M. Krusius; V. S. L'vov

    2010-05-04

    Vortex flow remains laminar up to large Reynolds numbers (Re~1000) in a cylinder filled with 3He-B. This is inferred from NMR measurements and numerical vortex filament calculations where we study the spin up and spin down responses of the superfluid component, after a sudden change in rotation velocity. In normal fluids and in superfluid 4He these responses are turbulent. In 3He-B the vortex core radius is much larger which reduces both surface pinning and vortex reconnections, the phenomena, which enhance vortex bending and the creation of turbulent tangles. Thus the origin for the greater stability of vortex flow in 3He-B is a quantum phenomenon. Only large flow perturbations are found to make the responses turbulent, such as the walls of a cubic container or the presence of invasive measuring probes inside the container.

  5. Rotary pneumatic valve

    DOE Patents [OSTI]

    Hardee, Harry C. (Albuquerque, NM)

    1991-01-01

    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.

  6. Pneumatic battery : a chemical alternative to pneumatic energy storage

    E-Print Network [OSTI]

    Kojimoto, Nigel (Nigel C.)

    2012-01-01

    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 ...

  7. Pneumatic soil removal tool

    DOE Patents [OSTI]

    Neuhaus, John E. (Newport News, VA)

    1992-01-01

    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.

  8. Pneumatic soil removal tool

    DOE Patents [OSTI]

    Neuhaus, J.E.

    1992-10-13

    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.

  9. Pneumatic clutch apparatus

    SciTech Connect (OSTI)

    Kamio, T.

    1987-03-03

    A pneumatic clutch apparatus is described comprising: a pneumatic clutch disposed at the rear of a transmission and including a pneumatic actuator for engaging and disengaging the clutch, a rotary passage adapted to rotate together with the clutch and connected to the actuator; a stationary passage stationary with respect to the clutch and connected to a pneumatic pressure control mechanism disposed outside the clutch; and a rotary joint including a connecting passage for connecting the rotary passage and the stationary passage together; the rotary joint having a rotary portion to which the rotary passage is fixed and a stationary portion to which the stationary passage is fixed, and the stationary portion being fixed to a housing of the transmission and rotatably supporting the rotary portion. A cylindrical intermediate member is disposed between the rotary portion and the stationary portion of the rotary joint. Air passages in the stationary portion and the rotary portion are connected together through an air passage in the intermediate member. The intermediate member is rotatably fitted to the rotary portion and the stationary portion through seals which seal the air passage. A connecting mechanism is operable to connect the intermediate member to the rotary portion when the intermediate member and the rotary portion occupy a predetermined relative angular position.

  10. Continued Development and Improvement of Pneumatic Heavy Vehicles

    SciTech Connect (OSTI)

    Robert J. Englar

    2005-07-15

    The objective of this applied research effort led by Georgia Tech Research Institute is the application of pneumatic aerodynamic technology previously developed and patented by us to the design of an appropriate Heavy Vehicle (HV) tractor-trailer configuration, and experimental confirmation of this pneumatic configuration's improved aerodynamic characteristics. In Phases I to IV of our previous DOE program (Reference 1), GTRI has developed, patented, wind-tunnel tested and road-tested blown aerodynamic devices for Pneumatic Heavy Vehicles (PHVs) and Pneumatic Sports Utility Vehicles (PSUVs). To further advance these pneumatic technologies towards HV and SUV applications, additional Phase V tasks were included in the first year of a continuing DOE program (Reference 2). Based on the results of the Phase IV full-scale test programs, these Phase V tasks extended the application of pneumatic aerodynamics to include: further economy and performance improvements; increased aerodynamic stability and control; and safety of operation of Pneumatic HVs. Continued development of a Pneumatic SUV was also conducted during the Phase V program. Phase V was completed in July, 2003; its positive results towards development and confirmation of this pneumatic technology are reported in References 3 and 4. The current Phase VI of this program was incrementally funded by DOE in order to continue this technology development towards a second fuel economy test on the Pneumatic Heavy Vehicle. The objectives of this current Phase VI research and development effort (Ref. 5) fall into two categories: (1) develop improved pneumatic aerodynamic technology and configurations on smaller-scale models of the advanced Pneumatic Heavy Vehicle (PHV); and based on these findings, (2) redesign, modify, and re-test the modified full-scale PHV test vehicle. This second objective includes conduct of an on-road preliminary road test of this configuration to prepare it for a second series of SAE Type-U fuel economy evaluations, as described in Ref. 5. Both objectives are based on the pneumatic technology already developed and confirmed for DOE OHVT/OAAT in Phases I-V. This new Phase VI effort was initiated by contract amendment to the Phase V effort using carryover FY02 funds. This were conducted under a new and distinct project number, GTRI Project A-6935, separate from the Phase I-IV program. However, the two programs are closely integrated, and thus Phase VI continues with the previous program and goals.

  11. American Institute of Aeronautics and Astronautics An Experimental Study of the Stability of a Four-Vortex

    E-Print Network [OSTI]

    Nelson, Robert C.

    . Helium bubbles were introduced into the core region of individual vortices to visualize these wake. These results suggest that the use of helium bubbles is a suitable method for visualizing wake vortices programs can be divided into two categories, vortex detection and vortex alleviation. The vortex detection

  12. Pneumatic conveyance apparatus and process

    DOE Patents [OSTI]

    Heckendorn, Frank M.; Matzolf, Athneal D.; Hera, Kevin R.

    2010-05-04

    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.

  13. Pneumatic gap sensor and method

    DOE Patents [OSTI]

    Bagdal, Karl T. (Middletown, OH); King, Edward L. (Trenton, OH); Follstaedt, Donald W. (Middletown, OH)

    1992-01-01

    An apparatus and method for monitoring and maintaining a predetermined width in the gap between a casting nozzle and a casting wheel, wherein the gap is monitored by means of at least one pneumatic gap sensor. The pneumatic gap sensor is mounted on the casting nozzle in proximity to the casting surface and is connected by means of a tube to a regulator and a transducer. The regulator provides a flow of gas through a restictor to the pneumatic gap sensor, and the transducer translates the changes in the gas pressure caused by the proximity of the casting wheel to the pneumatic gap sensor outlet into a signal intelligible to a control device. The relative positions of the casting nozzle and casting wheel can thereby be selectively adjusted to continually maintain a predetermined distance between their adjacent surfaces. The apparatus and method enables accurate monitoring of the actual casting gap in a simple and reliable manner resistant to the extreme temperatures and otherwise hostile casting environment.

  14. Pneumatic gap sensor and method

    DOE Patents [OSTI]

    Bagdal, K.T.; King, E.L.; Follstaedt, D.W.

    1992-03-03

    An apparatus and method for monitoring and maintaining a predetermined width in the gap between a casting nozzle and a casting wheel, wherein the gap is monitored by means of at least one pneumatic gap sensor. The pneumatic gap sensor is mounted on the casting nozzle in proximity to the casting surface and is connected by means of a tube to a regulator and a transducer. The regulator provides a flow of gas through a restictor to the pneumatic gap sensor, and the transducer translates the changes in the gas pressure caused by the proximity of the casting wheel to the pneumatic gap sensor outlet into a signal intelligible to a control device. The relative positions of the casting nozzle and casting wheel can thereby be selectively adjusted to continually maintain a predetermined distance between their adjacent surfaces. The apparatus and method enables accurate monitoring of the actual casting gap in a simple and reliable manner resistant to the extreme temperatures and otherwise hostile casting environment. 6 figs.

  15. Sliding pressure control valve for pneumatic hammer drill

    DOE Patents [OSTI]

    Polsky, Yarom (Albuquerque, NM)

    2011-08-30

    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.

  16. Pneumatic pumping in centrifugal microfluidic platforms

    E-Print Network [OSTI]

    Gorkin, Robert; Clime, Liviu; Madou, Marc; Kido, Horacio

    2010-01-01

    T, Madou M (2009) Serial siphon valving for centrifugale J (2007) Integrated siphon-based metering and sedimen-pneumatic pumping to siphon priming. Keywords Centrifugal Á

  17. Pneumatic pumping in centrifugal microfluidic platforms

    E-Print Network [OSTI]

    Gorkin, Robert; Clime, Liviu; Madou, Marc; Kido, Horacio

    2010-01-01

    Reciprocating ?ow-based centrifugal micro?uidics mixer. RevSerial siphon valving for centrifugal micro?uidic platforms.PAPER Pneumatic pumping in centrifugal micro?uidic platforms

  18. Smart Pneumatic Artificial Muscle Actuator with Embedded Microfluidic Sensing

    E-Print Network [OSTI]

    Park, Yong-Lae

    Smart Pneumatic Artificial Muscle Actuator with Embedded Microfluidic Sensing Yong-Lae Park1 materials cannot be employed for large strains. In this paper, we propose a smart artificial pneumatic

  19. NUMERICAL SIMULATION OF VORTEX BREAKDOWN

    E-Print Network [OSTI]

    Prete, Vincenza Del

    2011-01-01

    irrotational vortex. NRC Con. Aero Rep. LR-378. Hald, O. &vortex breakdown" phenomenon. Aero Dept. , Imperial ColI.

  20. Pneumatic direct cylinder fuel injection system

    SciTech Connect (OSTI)

    Reinke, P.E.

    1988-09-20

    This patent describes a pneumatic direct cylinder fuel injection system for use in an internal combustion engine of the type having an engine block means with an air induction means for supplying induction air to cylinders in the engine block means, with each cylinder having a piston reciprocable therein so as to define a combustion chamber which includes a stratified charge chamber as a portion thereof, the system including a plurality of pneumatic injectors, with the pneumatic injector being supported by the engine block means in position to discharge an air/fuel mixture into an associate stratified charge chamber, each of the pneumatic injectors including a body means terminating at one end thereof in a nozzle body, a bore means through the body means and the nozzle body, a valve seat encircling the bore means at the outboard free end of the nozzle body, the opposite end of the bore means being connectable to a source of air at a predetermined pressure, a poppet valve operatively positioned in the bore means. The poppet value includes a head movable between an open position and closed position relative to the valve seat and a stem extending from the head and defining with the bore means an air passage, control means operatively associated with the poppet valve to normally maintain the poppet valve in the closed position and being operative to permit movement of the poppet valve to the open position and, an electromagnetic fuel injector operatively positioned in the body means for injecting pressurized fuel into the air passage upstream of the head of the poppet valve in terms of the direction of air flow through the air passage during a compression stroke of the piston in the associate cylinder, the arrangement being such that when the compression pressure reaches a predetermined pressure the poppet valve will be moved to the valve closed position.

  1. Distinct magnetic signatures of fractional vortex configurations in multiband superconductors

    SciTech Connect (OSTI)

    Silva, R. M. da; Domínguez, D.; Aguiar, J. Albino

    2014-12-08

    Vortices carrying fractions of a flux quantum are predicted to exist in multiband superconductors, where vortex core can split between multiple band-specific components of the superconducting condensate. Using the two-component Ginzburg-Landau model, we examine such vortex configurations in a two-band superconducting slab in parallel magnetic field. The fractional vortices appear due to the band-selective vortex penetration caused by different thresholds for vortex entry within each band-condensate, and stabilize near the edges of the sample. We show that the resulting fractional vortex configurations leave distinct fingerprints in the static measurements of the magnetization, as well as in ac dynamic measurements of the magnetic susceptibility, both of which can be readily used for the detection of these fascinating vortex states in several existing multiband superconductors.

  2. SELFSIMILAR SOLUTIONS OF THE BINORMAL FLOW AND THEIR STABILITY

    E-Print Network [OSTI]

    Banica, Manuela Valeria

    [DaR] as a model which describes the flow of a vortex filament. That is to a say a vortex tube, Spain Abstract We review some recent results concerning the evolution of a vortex filament and its to their stability are studied. Keywords: vortex filaments, selfsimilarity, non-linear Schr¨odinger. Contents 1

  3. Development of dense-phase pneumatic transport of coal

    SciTech Connect (OSTI)

    Horisaka, S.; Ikemiya, H.; Kajiwara, T. [Sumitomo Metal Industries, Ltd., Kashima, Ibaraki (Japan)

    1996-12-31

    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).

  4. Control of a Pneumatic Orthosis for Upper Extremity Stroke Rehabilitation

    E-Print Network [OSTI]

    Bobrow, James E.

    Control of a Pneumatic Orthosis for Upper Extremity Stroke Rehabilitation Eric T. Wolbrecht, John Leavitt, David J. Reinkensmeyer, and James E. Bobrow Abstract-- A key challenge in rehabilitation robotics rehabilitation of the arm. Pneumatic actuators can potentially help meet this challenge because of their high

  5. A finite element analysis of pneumatic-tire/sand interactions

    E-Print Network [OSTI]

    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

  6. MODELING OF HYDRO-PNEUMATIC ENERGY STORAGE USING PUMP TURBINES

    E-Print Network [OSTI]

    Paris-Sud XI, Université 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

  7. NUMERICAL SIMULATION OF VORTEX BREAKDOWN

    E-Print Network [OSTI]

    Prete, Vincenza Del

    2011-01-01

    axis of the tube and is called the vortex core. The basicthe tube plus a perturbation caused by the vortex breakdown.of the tube. Thus the occurrence of the vortex breakdown

  8. Development of Pneumatic Aerodynamic Devices to Improve the Performance, Economics, and Safety of Heavy Vehicles

    SciTech Connect (OSTI)

    Robert J. Englar

    2000-06-19

    Under contract to the DOE Office of Heavy Vehicle Technologies, the Georgia Tech Research Institute (GTRI) is developing and evaluating pneumatic (blown) aerodynamic devices to improve the performance, economics, stability and safety of operation of Heavy Vehicles. The objective of this program is to apply the pneumatic aerodynamic aircraft technology previously developed and flight-tested by GTRI personnel to the design of an efficient blown tractor-trailer configuration. Recent experimental results obtained by GTRI using blowing have shown drag reductions of 35% on a streamlined automobile wind-tunnel model. Also measured were lift or down-load increases of 100-150% and the ability to control aerodynamic moments about all 3 axes without any moving control surfaces. Similar drag reductions yielded by blowing on bluff afterbody trailers in current US trucking fleet operations are anticipated to reduce yearly fuel consumption by more than 1.2 billion gallons, while even further reduction is possible using pneumatic lift to reduce tire rolling resistance. Conversely, increased drag and down force generated instantaneously by blowing can greatly increase braking characteristics and control in wet/icy weather due to effective ''weight'' increases on the tires. Safety is also enhanced by controlling side loads and moments caused on these Heavy Vehicles by winds, gusts and other vehicles passing. This may also help to eliminate the jack-knifing problem if caused by extreme wind side loads on the trailer. Lastly, reduction of the turbulent wake behind the trailer can reduce splash and spray patterns and rough air being experienced by following vehicles. To be presented by GTRI in this paper will be results developed during the early portion of this effort, including a preliminary systems study, CFD prediction of the blown flowfields, and design of the baseline conventional tractor-trailer model and the pneumatic wind-tunnel model.

  9. MHK Technologies/Pneumatically Stabilized Platform PSP | Open Energy

    Open Energy Info (EERE)

    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 on Google Bookmark EERE: Alternative Fuels Data Center Home Page on QA:QA J-E-1 SECTION J APPENDIXsource HistoryScenarios Towards 2050Enermar <OMI CombinedOsprey <Information

  10. Improved vortex reactor system

    DOE Patents [OSTI]

    Diebold, James P. (Lakewood, CO); Scahill, John W. (Evergreen, CO)

    1995-01-01

    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.

  11. Vortex diode jet

    DOE Patents [OSTI]

    Houck, Edward D. (Idaho Falls, ID)

    1994-01-01

    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.

  12. On the use of the double floating probe method to infer the difference between the electron and the heavy particles temperatures in an atmospheric pressure, vortex-stabilized nitrogen plasma jet

    SciTech Connect (OSTI)

    Prevosto, L. Mancinelli, B. R.; Kelly, H.; Instituto de Física del Plasma , Departamento de Física, Facultad de Ciencias Exactas y Naturales Ciudad Universitaria Pab. I, 1428 Buenos Aires

    2014-05-15

    Sweeping double probe measurements in an atmospheric pressure direct current vortex-stabilized plasma jet are reported (plasma conditions: 100 A discharge current, N{sub 2} gas flow rate of 25 Nl/min, thoriated tungsten rod-type cathode, copper anode with 5 mm inner diameter). The interpretation of the double probe characteristic was based on a generalization of the standard double floating probe formulae for non-uniform plasmas coupled to a non-equilibrium plasma composition model. Perturbations caused by the current to the probe together with collisional and thermal processes inside the probe perturbed region were taken into account. Radial values of the average electron and heavy particle temperatures as well as the electron density were obtained. The calculation of the temperature values did not require any specific assumption about a temperature relationship between different particle species. An electron temperature of 10?900 ± 900 K, a heavy particle temperature of 9300 ± 900 K, and an electron density of about 3.5 × 10{sup 22} m{sup ?3} were found at the jet centre at 3.5 mm downstream from the torch exit. Large deviations from kinetic equilibrium were found toward the outer border of the plasma jet. These results showed good agreement with those previously reported by the authors by using a single probe technique. The calculations have shown that this method is particularly useful for studying spraying-type plasma torches operated at power levels of about 15 kW.

  13. Inline evenflow material distributor for pneumatic material feed systems

    DOE Patents [OSTI]

    Thiry, Michael J. (Oakdale, CA)

    2007-02-20

    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.

  14. The Holographic Superconductor Vortex

    E-Print Network [OSTI]

    Marc Montull; Alex Pomarol; Pedro J. Silva

    2009-09-02

    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.

  15. Improved vortex reactor system

    DOE Patents [OSTI]

    Diebold, J.P.; Scahill, J.W.

    1995-05-09

    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.

  16. Pneumatic solids feeder for coal gasification reactor

    SciTech Connect (OSTI)

    Notestein, J.E.; Halow, J.S.

    1991-12-31

    This invention is comprised of a pneumatic feeder system for a coal gasification reactor which includes one or more feeder tubes entering the reactor above the level of the particle bed inside the reactor. The tubes are inclined downward at their outer ends so that coal particles introduced into the tubes through an aperture at the top of the tubes slides downward away from the reactor and does not fall directly into the reactor. Pressurized gas introduced into, or resulting from ignition of recycled combustible gas in a chamber adjacent to the tube ends, propels the coal from the tube into the reactor volume and onto the particle bed. Leveling of the top of the bed is carried out by a bladed rotor mounted on the reactor stirring shaft. Coal is introduced into the tubes from containers above the tubes by means of rotary valves placed across supply conduits. This system avoids placement of feeder hardware in the plenum above the particle bed and keeps the coal from being excessively heated prior to reaching the particle bed.

  17. Vortex-Based Aero- and Hydrodynamic Estimation

    E-Print Network [OSTI]

    Hemati, Maziar Sam

    2013-01-01

    Vortex-Based Aero- and Hydrodynamic Estimation . . . . . .2 Aero- andbenefit from vortex-based aero- and hydrodynamic estimation.

  18. Classification and volumetric analysis of temporal bone pneumatization using cone beam computed tomography

    E-Print Network [OSTI]

    Terasaki, Mark

    Classification and volumetric analysis of temporal bone pneumatization using cone beam computed Objective. This study performed volumetric analysis and classified different repeated patterns of temporal. Volumetric analysis of the pneumatization was performed using a window thresholding procedure on multiplanar

  19. A Pneumatic Actuated Microfluidic Beads-Trapping Device

    SciTech Connect (OSTI)

    Shao, Guocheng; Cai, Ziliang; Wang, Jun; Wang, Wanjun; Lin, Yuehe

    2011-08-20

    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.

  20. A real time neural energy management strategy for a hybrid pneumatic engine

    E-Print Network [OSTI]

    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

  1. Design of a Free Piston Pneumatic Compressor as a Mobile Robot Power Supply

    E-Print Network [OSTI]

    Barth, Eric J.

    technology is intended to provide a compact pneumatic power supply source appropriate for human-scale robotsDesign 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

  2. Passive Tele-operation of Pneumatic Powered Robotic Rescue Crawler Proc. of 6th

    E-Print Network [OSTI]

    Li, Perry Y.

    Passive Tele-operation of Pneumatic Powered Robotic Rescue Crawler ________________________________________________________________________________________________________________________ Proc. of 6th FPNI-PhD Symp. West Lafayette 2010, pp. 451-466 451 PASSIVE TELE-OPERATION OF PNEUMATIC, a passive bilateral tele-operation of a pneumatic powered robotic crawler is presented. The crawler

  3. Variations on stability

    E-Print Network [OSTI]

    Ruben Minasian; Alessandro Tomasiello

    2002-05-07

    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.

  4. Variations on stability

    E-Print Network [OSTI]

    Minasian, R; Minasian, Ruben; Tomasiello, Alessandro

    2001-01-01

    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.

  5. Programmable active droplet generation enabled by integrated pneumatic micropumps

    E-Print Network [OSTI]

    Zeng, Yong; Shin, Mimi; Wang, Tanyu

    2013-01-01

    Cite this: Lab Chip, 2013, 13, 267 Programmable active droplet generation enabled by integrated pneumatic micropumps Received 8th August 2012, Accepted 19th October 2012 DOI: 10.1039/c2lc40906b www.rsc.org/loc Yong Zeng,*abc Mimi Shinab and Tanyu... susceptibility to the physical properties of samples and devices (e.g. capacitance and dielectric strength).38 Pneumatic valves fabricated by soft lithography have been demonstrated to be a promising technique for controlled droplet forma- a...

  6. Prognostics for Ground Support Systems: Case Study on Pneumatic Valves

    E-Print Network [OSTI]

    Daigle, Matthew

    are used to control the flow of propellant, so failures may have a significant impact on launch to control the flow of propellant, failures may have a significant impact on launch availability. HencePrognostics for Ground Support Systems: Case Study on Pneumatic Valves Matthew Daigle University

  7. Vortex-Based Aero- and Hydrodynamic Estimation

    E-Print Network [OSTI]

    Hemati, Maziar Sam

    2013-01-01

    1. The strength of a vortex tube is uniform along the tube.3. The strength of a vortex tube is invariant in time. Theof Vortex Ring Formation at the Edge of a Circular Tube. ”

  8. GREEN'S FUNCTIONS OF VORTEX OPERATORS

    E-Print Network [OSTI]

    Polchinski, Joseph

    2013-01-01

    8 g Olesen vortex • , somewhere in space. The tube between cvortex operators have surface clustering, as this implies that magnetic flux is forming into tubes.

  9. Vortex Molecular Crystal and Vortex Plastic Crystal States in Honeycomb and Kagome Pinning Arrays

    E-Print Network [OSTI]

    C. Reichhardt; C. J. Olson Reichhardt

    2007-07-26

    Using numerical simulations, we investigate vortex configurations and pinning in superconductors with honeycomb and kagome pinning arrays. We find that a variety of novel vortex crystal states can be stabilized at integer and fractional matching field densities. The honeycomb and kagome pinning arrays produce considerably more pronounced commensuration peaks in the critical depinning force than triangular pinning arrays, and also cause additional peaks at noninteger matching fields where a portion of the vortices are located in the large interstitial regions of the pinning lattices. For the honeycomb pinning array, we find matching effects of equal strength at most fillings B/B_\\phi=n/2 for n>2, where n is an integer, in agreement with recent experiments. For kagome pinning arrays, pronounced matching effects generally occur at B/B_\\phi=n/3 for n>3, while for triangular pinning arrays pronounced matching effects are observed only at integer fillings B/B_\\phi=n. At the noninteger matching field peaks in the honeycomb and kagome pinning arrays, the interstitial vortices are arranged in dimer, trimer, and higher order n-mer states that have an overall orientational order. We call these n-mer states "vortex molecular crystals" and "vortex plastic crystals" since they are similar to the states recently observed in colloidal molecular crystal systems. We argue that the vortex molecular crystals have properties in common with certain spin systems such as Ising and n-state Potts models. We show that kagome and honeycomb pinning arrays can be useful for increasing the critical current above that of purely triangular pinning arrays.

  10. Low NOx Advanced Vortex Combustor

    SciTech Connect (OSTI)

    Edmonds, R.G. (Ramgen Power Systems, Inc., Bellevue, WA); Williams, J.T. (Ramgen Power Systems, Inc., Bellevue, WA); Steele, R.C. (EPRI); Straub, D.L.; Casleton, K.H.; Bining, Avtar (California Energy Commission, Sacramento, CA)

    2008-05-01

    A 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 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/unburned hydrocarbon (UHC) emissions of 4/4/0 ppmv (all emissions corrected to 15% O2 dry). The design also achieved less than 3 ppmv NOx with combustion efficiencies in excess of 99.5%. The design demonstrated marked 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, the measured 1.75% pressure drop is significantly lower than conventional gas turbine combustors, which could translate into an overall gas turbine cycle efficiency improvement. The relatively high velocities and low pressure drop achievable with this technology make the AVC approach an attractive alternative for syngas fuel applications.

  11. Motion of a helical vortex

    E-Print Network [OSTI]

    Fuentes, Oscar Velasco

    2015-01-01

    We study the motion of a single helical vortex in an unbounded, inviscid, incompressible fluid. The vortex is an infinite tube whose centerline is a helix and whose cross section is a circle of small radius (compared to the radius of curvature) where the vorticity is uniform and parallel to the centerline. Ever since Joukowsky (1912) deduced that this vortex translates and rotates steadily without change of form, numerous attempts have been made to compute these self-induced velocities. Here we use Hardin's (1982) solution for the velocity field to find new expressions for the vortex's linear and angular velocities. Our results, verified by numerically computing the Helmholtz integral and the Rosenhead-Moore approximation to the Biot-Savart law, are more accurate than previous results over the whole range of values of the vortex pitch and cross-section. We then use the new formulas to study the advection of passive particles near the vortex; we find that the vortex's motion and capacity to transport fluid dep...

  12. Elementary Vortex Processes in Thermal Superfluid Turbulence

    E-Print Network [OSTI]

    Kivotides, Demosthenes; Wilkin, S. Louise

    2009-01-01

    a complex system of vortex tubes has only (a vigorouslyIn this context, the vortex tube model (VTM) of Kivotidesstraight normal ?uid vortex tube, suggested an explicit

  13. Large vortex state in ferromagnetic disks

    E-Print Network [OSTI]

    Metlov, Konstantin L

    2013-01-01

    Magnetic vortices in soft ferromagnetic nano-disks have been extensively studied for at least several decades both for their fundamental (as a "live" macroscopic realization of a field theory model of an elementary particle) as well as applied value for high-speed high-density power-independent information storage. Here it is shown that there is another vortex state in nano-scale ferromagnetic disks of several exchange lengths in size. The energy of this large vortex state is computed numerically (within the framework of Magnetism@home distributed computing project) and its stability is studied analytically, which allows to plot it on magnetic phase diagram. It is the ground state of cylinders of certain sizes and is metastable in a wider set of geometries. Large vortices exist on par with classical ones, while being separated by an energy barrier, controllable by tuning the geometry and material of ferromagnetic disk. This state can be an excellent candidate for magnetic information storage not only because ...

  14. Gravity waves from vortex dipoles and jets 

    E-Print Network [OSTI]

    Wang, Shuguang

    2009-05-15

    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...

  15. CFD-DEM modelling of two-phase pneumatic conveying with experimental validation. 

    E-Print Network [OSTI]

    Ebrahimi, Mohammadreza

    2014-11-27

    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 ...

  16. Soft pneumatic artificial muscles with low threshold pressures for a cardiac compression device

    E-Print Network [OSTI]

    Obiajulu, Steven (Steven C.)

    2013-01-01

    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 ...

  17. Design of a pneumatically assisted shifting system for Formula SAE® racing applications

    E-Print Network [OSTI]

    Kennett, Andrew J. (Andrew John)

    2008-01-01

    An improved shifting system for use with the MIT Formula SAE race car was designed in order to provide drivers with a faster and easier means of shifting. The result of this design was a pneumatic shifting system weighing ...

  18. The determination of design data for the pneumatic conveying of sorghum seed 

    E-Print Network [OSTI]

    Person, Nat K

    1959-01-01

    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...

  19. An investigation of pneumatic control on immiscible contaminant migration in confined aquifers 

    E-Print Network [OSTI]

    Watts, John David

    1991-01-01

    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...

  20. Microtargeted gene silencing and ectopic expression in live embryos using biolistic delivery with a pneumatic capillary gun

    E-Print Network [OSTI]

    Shefi, Orit; Simonnet, Claire; Baker, Michael W; Glass, James R; Macagno, Eduardo R; Groisman, Alex

    2006-01-01

    a Pneumatic Capillary Gun Orit Shefi, 1 Claire Simonnet, 2medicinalis; netrin; gene gun Introduction Modulating geneby the current design of “gene guns” used for particle

  1. Hierarchical Colloidal Vortex Rings in a Constant Electric Field Yilong Han and David G. Grier

    E-Print Network [OSTI]

    Grier, David

    in the bulk of charge­stabilized colloidal suspensions when electrohydrodynamic forces due to constant appliedHierarchical Colloidal Vortex Rings in a Constant Electric Field Yilong Han and David G. Grier used [1, 2] to study interfacial col­ loidal electrokinetic phenomena. An aqueous suspension

  2. Hierarchical Colloidal Vortex Rings in a Constant Electric Field Yilong Han and David G. Grier

    E-Print Network [OSTI]

    Grier, David

    in the bulk of charge-stabilized colloidal suspensions when electrohydrodynamic forces due to constant appliedHierarchical Colloidal Vortex Rings in a Constant Electric Field Yilong Han and David G. Grier used [1, 2] to study interfacial col- loidal electrokinetic phenomena. An aqueous suspension

  3. Localized Induction Equation for Stretched Vortex Filament

    E-Print Network [OSTI]

    Kimiaki Konno; Hiroshi Kakuhata

    2006-03-02

    We study numerically the motion of the stretched vortex filaments by using the localized induction equation with the stretch and that without the stretch.

  4. Light propagation around a relativistic vortex flow of dielectric medium

    E-Print Network [OSTI]

    B. Linet

    2000-11-06

    We determine the path of the light around a dielectric vortex described by the relativistic vortex flow of a perfect fluid.

  5. Vortex Hydro Energy Develops Transformational Technology to Harness...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Vortex Hydro Energy Develops Transformational Technology to Harness Energy from Water Currents Vortex Hydro Energy Develops Transformational Technology to Harness Energy from Water...

  6. Controllable pneumatic generator based on the catalytic decomposition of hydrogen peroxide

    SciTech Connect (OSTI)

    Kim, Kyung-Rok; Kim, Kyung-Soo Kim, Soohyun

    2014-07-15

    This paper presents a novel compact and controllable pneumatic generator that uses hydrogen peroxide decomposition. A fuel micro-injector using a piston-pump mechanism is devised and tested to control the chemical decomposition rate. By controlling the injection rate, the feedback controller maintains the pressure of the gas reservoir at a desired pressure level. Thermodynamic analysis and experiments are performed to demonstrate the feasibility of the proposed pneumatic generator. Using a prototype of the pneumatic generator, it takes 6 s to reach 3.5 bars with a reservoir volume of 200 ml at the room temperature, which is sufficiently rapid and effective to maintain the repetitive lifting of a 1 kg mass.

  7. Automated system for removal and pneumatic transport of fly ash from electric precipitator hoppers

    SciTech Connect (OSTI)

    V.K. Konovalov; O.V. Yashkin; V.V. Ermakov

    2008-03-15

    A system for removal and pneumatic transport of fly ash is examined, in which air pulses act on batches (pistons) of ash formed in a duct. Studies are made of the effect of several physical parameters on the force required to displace a piston of ash and these serve as a basis for choosing a system for removal and pneumatic transport of ash simultaneously from several hoppers of an electric precipitator. This makes it possible to separate the ash particles according to size without introducing additional components. Formulas are given for calculating the structural and dynamic parameters of this system and measurements of indirect dynamic parameters are used to calculate the input-output characteristics of the system. In order to optimize the system, configurations for summing several ducts into a single transport duct for pneumatic ash transport are proposed. Some variants of dry ash utilization and the advantages of producing of size-separated particles are considered.

  8. The idea of vortex energy

    E-Print Network [OSTI]

    V. E. Shapiro

    2011-09-22

    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.

  9. Vortex Tubes of Turbulent Solar Convection

    E-Print Network [OSTI]

    Kitiashvili, I N; Mansour, N N; Lele, S K; Wray, A A

    2011-01-01

    Investigation of turbulent properties of solar convection is extremely important for understanding of the multi-scale dynamics observed on the solar surface. In particular, recent high-resolution observations revealed ubiquitous vortical structures, and numerical simulations demonstrated links between the vortex tube dynamics and magnetic field organization, and also importance of vortex tube interactions in the mechanism of acoustic wave excitation on the Sun. In this paper we investigate mechanisms of formation of vortex tubes in highly-turbulent convective flows near the solar surface by using realistic radiative hydrodynamic LES simulations. Analysis of data, obtained by the simulations, indicates two basic processes of the vortex tube formation: 1) development of small-scale convective instability inside convective granules, and 2) a Kelvin-Helmholtz type instability of shearing flows in intergranular lanes. Our analysis shows that vortex stretching during these processes is a primary source of generatio...

  10. EXISTENCE OF KNOTTED VORTEX TUBES IN STEADY EULER FLOWS

    E-Print Network [OSTI]

    Enciso, Alberto

    EXISTENCE OF KNOTTED VORTEX TUBES IN STEADY EULER FLOWS ALBERTO ENCISO AND DANIEL PERALTA-SALAS Abstract. We prove the existence of knotted and linked thin vortex tubes for steady solutions of vortex tubes of a Beltrami field that tends to zero at infinity. The structure of the vortex lines

  11. Vortex pinning by inhomogeneities in type-II superconductors

    E-Print Network [OSTI]

    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

  12. Under consideration for publication in J. Fluid Mech. 1 Some steady axisymmetric vortex ows past

    E-Print Network [OSTI]

    Fornberg, Bengt

    include vortex rings, bounded vortices attached to the sphere and in nite vortex tubes. Four families to be considered: vortex rings, bounded vortices attached to the sphere, and vortex tubes" extending to in nity. Fornberg and K. Miller = 0: attached vortex vortex ring > 0: vortex tube Figure 1. Examples

  13. PASSIVE BILATERAL TELE-OPERATION AND HUMAN POWER AMPLIFICATION WITH PNEUMATIC ACTUATORS

    E-Print Network [OSTI]

    Li, Perry Y.

    PASSIVE BILATERAL TELE-OPERATION AND HUMAN POWER AMPLIFICATION WITH PNEUMATIC ACTUATORS Venkat the human power input. From sys- tems theory [1], it is known that closed loop interaction between a passive Durbha Center for Compact and Efficient Fluid Power Department of Mechanical Engineering University

  14. A Soft Wearable Robotic Device for Active Knee Motions using Flat Pneumatic Artificial Muscles

    E-Print Network [OSTI]

    Park, Yong-Lae

    A 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 elastomer muscles were employed for assisted knee extension and flexion. The robotic device was tested

  15. Modeling the pneumatic subsystem of a S-cam air brake system 

    E-Print Network [OSTI]

    Coimbatore Subramanian, Shankar

    2004-09-30

    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...

  16. SLIDING MODE CONTROL OF PIEZOELECTRIC VALVE REGULATED PNEUMATIC ACTUATOR FOR MRI-COMPATIBLE ROBOTIC INTERVENTION

    E-Print Network [OSTI]

    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

  17. Vortex Lattices and Crystalline Geometries

    E-Print Network [OSTI]

    Ning Bao; Sarah Harrison; Shamit Kachru; Subir Sachdev

    2013-04-16

    We consider $AdS_2 \\times R^2$ solutions supported by a magnetic field, such as those which arise in the near-horizon limit of magnetically charged $AdS_4$ Reissner-Nordstrom black branes. In the presence of an electrically charged scalar field, such magnetic solutions can be unstable to spontaneous formation of a vortex lattice. We solve the coupled partial differential equations which govern the charged scalar, gauge field, and metric degrees of freedom to lowest non-trivial order in an expansion around the critical point, and discuss the corrections to the free energy and thermodynamic functions arising from the formation of the lattice. We describe how such solutions can also be interpreted, via S-duality, as characterizing infrared crystalline phases of conformal field theories doped by a chemical potential, but in zero magnetic field; the doped conformal field theories are dual to geometries that exhibit dynamical scaling and hyperscaling violation.

  18. Airfoil Vortex Induced Vibration suppression devices

    E-Print Network [OSTI]

    Lee, Evan J. (Evan Joseph)

    2007-01-01

    Vortex Induced Vibrations (VIV) is a major concern of the offshore oil industry. This problem leads to fatigue failure in the marine risers and causes costly replacement of the risers. Appendages such as helical strakes ...

  19. Identification and control of a pneumatic robot Emanuel Todorov1, Chunyan Hu1, Alex Simpkins1 and Javier Movellan2

    E-Print Network [OSTI]

    Simpkins, Alex

    introduce a low-pass filter between command signals and forces, with similar time-constants for muscles are actuated by pneumatic cylinders, with separate pressure sensors and valves for each chamber. Due

  20. Improving Building Comfort and Energy Savings of the McKenzie Airport Terminal by Maintaining and Improving Pneumatic Control Systems 

    E-Print Network [OSTI]

    Liu, C.; Bruner, H. L.; Deng, S.; Brundidge, T.; Turner, W. D.; Claridge, D. E.

    2004-01-01

    , 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...

  1. Topological analysis of paraxially scattered electron vortex beams

    E-Print Network [OSTI]

    Axel Lubk; Laura Clark; Giulio Guzzinati; Jo Verbeeck

    2014-10-10

    We investigate topological aspects of sub-nm electron vortex beams upon elastic propagation through atomic scattering potentials. Two main aspects can be distinguished: (i) Significantly reduced delocalization compared to a similar non-vortex beam if the beam centers on an atomic column and (ii) site symmetry dependent splitting of higher-order vortex beams. Furthermore, the results provide insight into the complex vortex line fabric within the elastically scattered wave containing characteristic vortex loops predominantly attached to atomic columns and characteristic twists of vortex lines around atomic columns.

  2. Hydrodynamic injection with pneumatic valving for microchip electrophoresis with total analyte utilization

    SciTech Connect (OSTI)

    Sun, Xuefei; Kelly, Ryan T.; Danielson, William F.; Agrawal, Nitin; Tang, Keqi; Smith, Richard D.

    2011-04-26

    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.

  3. Magnetic Vortex Core Reversal by Low-Field Excitations

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    Magnetic Vortex Core Reversal by Low-Field Excitations Magnetic Vortex Core Reversal by Low-Field Excitations Print Wednesday, 28 March 2007 00:00 In micrometer-sized magnetic thin...

  4. Geometric phases for corotating elliptical vortex patches B. N. Shashikantha)

    E-Print Network [OSTI]

    Shashikanth, Banavara N.

    of an infinitely long rectilinear vortex tube of area A whose vorticity distribution is invariant along the lengthGeometric phases for corotating elliptical vortex patches B. N. Shashikantha) Control and Dynamical September 2000 We describe a geometric phase that arises when two elliptical vortex patches co- rotate

  5. Quasi-two Dimensional Hydrodynamics and Interaction of Vortex Tubes

    E-Print Network [OSTI]

    Zakharov, Vladimir

    Quasi-two Dimensional Hydrodynamics and Interaction of Vortex Tubes Vladimir Zakharov 1 but a careful study of the dynamics of the vortex tubes or their systems in a real 3-dimentional nonstationary for description of this type of flow looks very timely. Another motivation is the vortex dynamics

  6. Rogue Waves on a Vortex Filament St Anne's College

    E-Print Network [OSTI]

    Tarrès, Pierre

    Rogue Waves on a Vortex Filament Rehan Shah St Anne's College University of Oxford A dissertation;Abstract The presence of a standing soliton on a vortex filament has been demonstrated theoretically of the local induction approximation (LIA) governing the motion of a thin vortex filament to those of nonlinear

  7. Inelastic electron-vortex-beam scattering

    E-Print Network [OSTI]

    Ruben Van Boxem; Bart Partoens; Jo Verbeeck

    2015-03-16

    Recent theoretical and experimental developments in the field of electron vortex beam physics have raised questions on what exactly this novelty in the field of electron microscopy (and other fields, such as particle physics) really provides. An important part in the answer to those questions lies in scattering theory. The present investigation explores various aspects of inelastic quantum scattering theory for cylindrically symmetric beams with orbital angular momentum. The model system of Coulomb scattering on a hydrogen atom provides the setting to address various open questions: How is momentum transferred? Do vortex beams selectively excite atoms, and how can one employ vortex beams to detect magnetic transitions? The analytical approach presented here provides answers to these questions. OAM transfer is possible, but not through selective excitation; rather, by pre- and post-selection one can filter out the relevant contributions to a specific signal.

  8. Chiral specific electron vortex beam spectroscopy

    E-Print Network [OSTI]

    J. Yuan; S. M. Lloyd; M. Babiker

    2013-07-29

    Electron vortex beams carry well-defined orbital angular momentum (OAM) about the propagation axis. Such beams are thus characterised by chirality features which make them potentially useful as probes of magnetic and other chiral materials. An analysis of the inelastic processes in which electron vortex beams interact with atoms and which involve OAM exchange is outlined, leading to the multipolar selection rules governing this chiral specific electron vortex beam spectroscopy. Our results show clearly that the selection rules are dependent on the dynamical state and location of the atoms involved. In the most favorable scenario, this form of electron spectroscopy can induce magnetic sublevel transitions which are commonly probed using circularly polarized photon beams.

  9. Optical vortex array in spatially varying lattice

    E-Print Network [OSTI]

    Kapoor, Amit; Senthilkumaran, P; Joseph, Joby

    2015-01-01

    We present an experimental method based on a modified multiple beam interference approach to generate an optical vortex array arranged in a spatially varying lattice. This method involves two steps which are: numerical synthesis of a consistent phase mask by using two-dimensional integrated phase gradient calculations and experimental implementation of produced phase mask by utilizing a phase only spatial light modulator in an optical 4f Fourier filtering setup. This method enables an independent variation of the orientation and period of the vortex lattice. As working examples, we provide the experimental demonstration of various spatially variant optical vortex lattices. We further confirm the existence of optical vortices by formation of fork fringes. Such lattices may find applications in size dependent trapping, sorting, manipulation and photonic crystals.

  10. Convectively driven vortex flows in the Sun

    E-Print Network [OSTI]

    J. A. Bonet; I. Marquez; J. Sanchez Almeida; I. Cabello; V. Domingo

    2008-09-23

    We have discovered small whirlpools in the Sun, with a size similar to the terrestrial hurricanes (<~0.5 Mm). The theory of solar convection predicts them, but they had remained elusive so far. The vortex flows are created at the downdrafts where the plasma returns to the solar interior after cooling down, and we detect them because some magnetic bright points (BPs) follow a logarithmic spiral in their way to be engulfed by a downdraft. Our disk center observations show 0.009 vortexes per Mm^2, with a lifetime of the order of 5 min, and with no preferred sense of rotation. They are not evenly spread out over the surface, but they seem to trace the supergranulation and the mesogranulation. These observed properties are strongly biased by our type of measurement, unable to detect vortexes except when they are engulfing magnetic BPs.

  11. Crystalline Geometries from Fermionic Vortex Lattice

    E-Print Network [OSTI]

    M. Reza Mohammadi Mozaffar; Ali Mollabashi

    2013-08-08

    We study charged Dirac fermions on an AdS$_2\\times R^2$ background with a non-zero magnetic field. Under certain boundary conditions, we show that the charged fermion can make the background unstable, resulting in spontaneously formation of a vortex lattice. We observe that an electric field emerges in the back-reacted solution due to the vortex lattice constructed from spin polarized fermions. This electric field may be extended to the UV boundary which leads to a finite charge density. We also discuss corrections to the thermodynamic functions due to the lattice formation.

  12. Existence of knotted vortex tubes in steady Euler flows

    E-Print Network [OSTI]

    Alberto Enciso; Daniel Peralta-Salas

    2014-10-23

    We prove the existence of knotted and linked thin vortex tubes for steady solutions to the incompressible Euler equation in R^3. More precisely, given a finite collection of (possibly linked and knotted) disjoint thin tubes in R^3, we show that they can be transformed with a C^m-small diffeomorphism into a set of vortex tubes of a Beltrami field that tends to zero at infinity. The structure of the vortex lines in the tubes is extremely rich, presenting a positive-measure set of invariant tori and infinitely many periodic vortex lines. The problem of the existence of steady knotted vortex tubes can be traced back to Lord Kelvin.

  13. Neutron Scattering Studies of Vortex Matter in Type-II Superconductors

    SciTech Connect (OSTI)

    Xinsheng Ling

    2012-02-02

    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.

  14. On the evolution of vortex rings with swirl

    SciTech Connect (OSTI)

    Naitoh, Takashi, E-mail: naitoh.takashi@nitech.ac.jp [Department of Engineering Physics, Electronics and Mechanics, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Okura, Nobuyuki, E-mail: ohkura@meijo-u.ac.jp [Department of Vehicle and Mechanical Engineering, Meijo University, 1-501 Shiogamaguchi Tempaku-ku, Nagoya 468-8502 (Japan); Gotoh, Toshiyuki, E-mail: gotoh.toshiyuki@nitech.ac.jp [Department of Scientific and Engineering Simulation, Graduate School of Engineering, Nagoya Institute of Technology, Gokiso-cho, Showa-ku, Nagoya 466-8555 (Japan); Kato, Yusuke [Controller Business Unit Engineering Division 1, Engineering Department 3, Denso Wave Incorporated, 1 Yoshiike Kusagi Agui-cho, Chita-gun Aichi 470-2297 (Japan)

    2014-06-15

    A laminar vortex ring with swirl, which has the meridional velocity component inside the vortex core, was experimentally generated by the brief fluid ejection from a rotating outlet. The evolution of the vortex ring was investigated with flow visualizations and particle image velocimetry measurements in order to find the influence of swirling flow in particular upon the transition to turbulence. Immediately after the formation of a vortex ring with swirl, a columnar strong vortex along the symmetric axis is observed in all cases of the present experiment. Then the characteristic fluid discharging from a vortex ring with swirl referred to as “peeling off” appears. The amount of discharging fluid due to the “peeling off” increases with the angular velocity of the rotating outlet. We conjectured that the mechanism generating the “peeling off” is related to the columnar strong vortex by close observations of the spatio-temporal development of the vorticity distribution and the cutting 3D images constructed from the successive cross sections of a vortex ring. While a laminar vortex ring without swirl may develop azimuthal waves around its circumference at some later time and the ring structure subsequently breaks, the swirling flow in a vortex ring core reduces the amplification rate of the azimuthal wavy deformation and preserved its ring structure. Then the traveling distance of a vortex ring can be extended using the swirl flow under certain conditions.

  15. Vortex dynamics in 4 Banavara N. Shashikanth

    E-Print Network [OSTI]

    Shashikanth, Banavara N.

    of oblique vortex shedding behind a heated circular cylinder in laminar wake regime Phys. Fluids 24, 011701 dynamics of Euler's equations for a constant density fluid flow in R4 is studied. Most of the paper focuses of such work are in Refs. 31, 24, 12, 14, and 11. It is fair to say that, in general, classical fluid flows

  16. Quenching Processes in Flame-Vortex Interactions

    E-Print Network [OSTI]

    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

  17. Variable gearing in a biologically inspired pneumatic actuator array This article has been downloaded from IOPscience. Please scroll down to see the full text article.

    E-Print Network [OSTI]

    Azizi, Manny

    Variable gearing in a biologically inspired pneumatic actuator array This article has been) 026002 (8pp) doi:10.1088/1748-3182/8/2/026002 Variable gearing in a biologically inspired pneumatic. The velocity advantage resulting from dynamic changes in pennation angle can be characterized as a gear ratio

  18. Development of the prototype pneumatic transfer system for ITER neutron activation system

    SciTech Connect (OSTI)

    Cheon, M. S.; Seon, C. R.; Pak, S.; Lee, H. G.; Bertalot, L.

    2012-10-15

    The neutron activation system (NAS) measures neutron fluence at the first wall and the total neutron flux from the ITER plasma, providing evaluation of the fusion power for all operational phases. The pneumatic transfer system (PTS) is one of the key components of the NAS for the proper operation of the system, playing a role of transferring encapsulated samples between the capsule loading machine, irradiation stations, counting stations, and disposal bin. For the validation and the optimization of the design, a prototype of the PTS was developed and capsule transfer tests were performed with the developed system.

  19. Water gate array for current flow or tidal movement pneumatic harnessing system

    DOE Patents [OSTI]

    Gorlov, Alexander M. (Brookline, MA)

    1991-01-01

    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.

  20. Fabrication, assembly, bench and drilling tests of two prototype downhole pneumatic turbine motors: Final technical report

    SciTech Connect (OSTI)

    Bookwalter, R.; Duettra, P.D.; Johnson, P.; Lyons, W.C.; Miska, S.

    1987-04-01

    The first and second prototype downhole pneumatic turbine motors have been fabricated, assembled and tested. All bench tests showed that the motor will produce horsepower and bit speeds approximating the predicted values. Specifically, the downhole pneumatic turbine motor produced approximately 50 horsepower at 100 rpm, while being supplied with about 3600 SCFM of compressed air. The first prototype was used in a drilling test from a depth of 389 feet to a depth of 789 feet in the Kirtland formation. This first prototype motor drilled at a rate exceeding 180 ft/hr, utilizing only 3000 SCFM of compressed air. High temperature tests (at approximately 460/sup 0/F) were carried out on the thrust assembly and the gearboxes for the two prototypes. These components operated successfully at these temperatures. Although the bench and drilling tests were successful, the tests revealed design changes that should be made before drilling tests are carried out in geothermal boreholes at the Geysers area, near Santa Rosa, California.

  1. Strings, vortex rings, and modes of instability

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gubser, Steven S.; Nayar, Revant; Parikh, Sarthak

    2015-03-01

    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

  2. Origin and dynamics of vortex rings in drop splashing

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Lee, Ji San; Park, Su Ji; Lee, Jun Ho; Weon, Byung Mook; Fezzaa, Kamel; Je, Jung Ho

    2015-09-04

    A vortex is a flow phenomenon that is very commonly observed in nature. More than a century, a vortex ring that forms during drop splashing has caught the attention of many scientists due to its importance in understanding fluid mixing and mass transport processes. However, the origin of the vortices and their dynamics remain unclear, mostly due to the lack of appropriate visualization methods. Here, with ultrafast X-ray phase-contrast imaging, we show that the formation of vortex rings originates from the energy transfer by capillary waves generated at the moment of the drop impact. Interestingly, we find a row ofmore »vortex rings along the drop wall, as demonstrated by a phase diagram established here, with different power-law dependencies of the angular velocities on the Reynolds number. These results provide important insight that allows understanding and modelling any type of vortex rings in nature, beyond just vortex rings during drop splashing.« less

  3. Vortex Bubble Formation in Pair Plasmas

    E-Print Network [OSTI]

    Berezhiani, V I; Mahajan, S M; Aleksi?, B N

    2013-01-01

    It is shown that delocalized vortex solitons in relativistic pair plasmas with small temperature asymmetries can be unstable for intermediate intensities of the background electromagnetic field. Instability leads to the generation of ever-expanding cavitating bubbles in which the electromagnetic fields are zero. The existence of such electromagnetic bubbles is demonstrated by qualitative arguments based on a hydrodynamic analogy, and by numerical solutions of the appropriate Nonlinear Schr\\"odinger equation with a saturating nonlinearity.

  4. Liquid Vortex Shielding for Fusion Energy Applications

    SciTech Connect (OSTI)

    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)

    2005-05-15

    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.

  5. STORAGE FUNCTION FOR PASSIVITY ANALYSIS OF PNEUMATIC ACTUATORS WITH FINITE HEAT TRANSFER IN HUMAN-INTERACTIVE SYSTEMS

    E-Print Network [OSTI]

    Li, Perry Y.

    crawler [2], and potentially as human power amplifiers [3], [4]. There is also on going research to passive operation of hydraulic human power ampli- fier was reported. These ideas were extended to a pneumatic human power amplifier in [3], [11]. Energetic passivity analysis requires a model of the system

  6. Fault diagnosis of pneumatic systems with artificial neural network algorithms M. Demetgul a,*, I.N. Tansel b

    E-Print Network [OSTI]

    Rucci, Michele

    the pneumatic system worked perfectly and had some faults including empty magazine, zero vacuum, inappropriate, not vacuuming the material and low air pressure. The signals of eight sensors were collected during the entire, 2008), automobile engines, bearings, hydraulic servo-valves, servomotors, check-valves (Seong et al

  7. Simple Passive Valves for Addressable Pneumatic Actuation Nils Napp, Brandon Araki+, Michael T. Tolley, Radhika Nagpal, Robert J. Wood

    E-Print Network [OSTI]

    Napp, Nils

    Simple Passive Valves for Addressable Pneumatic Actuation Nils Napp, Brandon Araki+, Michael T simple passive devices that behave like leaky check valves. We present the theory of operation and design, and demonstrate the approach by building prototype valves and using them to control serially connected soft

  8. Electron vortex orbits and merger T. B. Mitchella)

    E-Print Network [OSTI]

    California at San Diego, University of

    of the spatially extended vortices are calculated by the point vortex approximation, and simple rules are used resulted in predictions for tim

  9. Dual vortex theory of strongly interacting electrons: A non-Fermi...

    Office of Scientific and Technical Information (OSTI)

    Dual vortex theory of strongly interacting electrons: A non-Fermi liquid with a twist Citation Details In-Document Search Title: Dual vortex theory of strongly interacting...

  10. Magnetorotational instability, current relaxation, and current-vortex sheet

    SciTech Connect (OSTI)

    Silveira, F. E. M. [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adélia, 166, CEP 09210-170, Bairro Bangu, Santo André, SP (Brazil)] [Centro de Ciências Naturais e Humanas, Universidade Federal do ABC, Rua Santa Adélia, 166, CEP 09210-170, Bairro Bangu, Santo André, SP (Brazil); Galvão, R. M. O. [Instituto de Física, Universidade de São Paulo, Rua do Matão, Travessa R, 187, CEP 05508-090, Cidade Universitária, São Paulo, SP (Brazil)] [Instituto de Física, Universidade de São Paulo, Rua do Matão, Travessa R, 187, CEP 05508-090, Cidade Universitária, São Paulo, SP (Brazil)

    2013-08-15

    The conjugate effect of current relaxation and of current-vortex sheet formation on the magnetorotational instability is explored in a conducting fluid. It is found that the relative amplification of the magnetic viscosity from marginal stability to the instability determined by the maximum growth rate is around 924% when resistive effects dominate, while the corresponding quantity is around 220% in the ideal limit. This shows that the conjugate influence is much more efficient to amplify the magnetic viscosity than just the effect due to the standard magnetic tension. It is also found that the magnitude of the magnetic viscosity is effectively enhanced by the conjugate influence. The results presented here may contribute to the understanding of the various processes that play a significant role in the mechanism of anomalous viscosity observed in Keplerian disks. It is argued that the new effect shall be relevant in thin accretion disks. It is also mentioned that the proposed formulation may be of interest for some theories of magnetic reconnection. Possible extensions of this work are suggested.

  11. Vibrating Cantilever Transducer Incorporated in Dual Diaphragms Structure for Sensing Differential Pneumatic Pressure

    E-Print Network [OSTI]

    Cellatoglu, Akin; 10.5121/ijsc.2011.2409

    2012-01-01

    Pneumatic pressure cells with thin metallic spherical diaphragm of shallow spherical shell configuration linked with vibrating wire pickup or vibrating cantilever pickup were reported in the past. In order to enhance the sensitivity of the pressure cell this work considers dual diaphragm structure fitted with cantilever pickup. The design and development of the pressure cell with this dual diaphragm structure having cantilever pickup is presented here. The geometrical design is optimally made as to sense either mono pressure or differential pressure resources. The cantilevers of the two diaphragms are excited to produce vibrations and the frequencies of vibrations are determined by picking up signals from orthogonally arranged opto-coupler links. With the computed frequency a lookup table is referred to obtain the pressure acting on the concerned diaphragm. In the external circuits, the average pressure and the differential pressure acting on two diaphragms are computed. Furthermore transmitting circuits taki...

  12. Finite-Element Modeling of Electrostatic Sensors for the Flow Measurement of Particles in Pneumatic Pipelines

    SciTech Connect (OSTI)

    Krabicka, J.; Yan, Y.

    2009-08-15

    Electrostatic sensors are used in certain industries for the flow measurement of pneumatically conveyed solids. However, despite various advances that have been made in recent years, relatively little information is known about the exact nature of the electrostatic charge induced onto the sensor electrode due to moving particles, which is dependent on electrode geometry, particle distribution, and particle velocity. This paper presents a novel approach to the study of the charge induced onto electrostatic sensors based on fitting a Lorentzian curve to the results of a finite-element model of the electrostatic sensor and pipeline. The modeling method is validated by comparing the modeling results of a nonintrusive circular electrode with an established analytical solution. The modeling results are used for in-depth analysis and informed design of a particular sensor configuration.

  13. Almost Optimal Convergence of the Point Vortex Method for Vortex Sheets using Numerical Filtering

    E-Print Network [OSTI]

    Ferguson, Thomas S.

    vortices, numerical filtering, discrete Cauchy­Kowalewski theorem. AMS subject classifications: primary 65M subsequent modes will be dominated by roundoff error. Since these highest modes are amplified the fastest, singularity formation appears to be generic, even for vortex sheets initially near equilibrium [13, 6, 19

  14. One-vortex moduli space and Ricci flow

    E-Print Network [OSTI]

    Nicholas S. Manton

    2008-05-02

    The metric on the moduli space of one abelian Higgs vortex on a surface has a natural geometrical evolution as the Bradlow parameter, which determines the vortex size, varies. It is shown by various arguments, and by calculations in special cases, that this geometrical flow has many similarities to Ricci flow.

  15. High-Resolution Simulations of Parallel BladeVortex Interactions

    E-Print Network [OSTI]

    Alonso, Juan J.

    to that encountered in the simulation of realistic helicopter blade­vortex interaction, but the computational costs aeroacoustics rotor tests [2,3]. These tests were performed on a Mach-scaled Bo-105 rotor and the blade loadsHigh-Resolution Simulations of Parallel Blade­Vortex Interactions Alasdair Thom University

  16. Finned Tube With Vortex Generators For A Heat Exchanger.

    DOE Patents [OSTI]

    Sohal, Manohar S. (Idaho Falls, ID); O'Brien, James E. (Idaho Falls, ID)

    2005-12-20

    A system for and method of manufacturing a finned tube for a heat exchanger is disclosed herein. A continuous fin strip is provided with at one pair of vortex generators. A tube is rotated and linearly displaced while the continuous fin strip with vortex generators is spirally wrapped around the tube.

  17. Finned Tube With Vortex Generators For A Heat Exchanger.

    DOE Patents [OSTI]

    Sohal, Monohar S. (Idaho Falls, ID); O'Brien, James E. (Idaho Falls, ID)

    2004-09-14

    A system for and method of manufacturing a finned tube for a heat exchanger is disclosed herein. A continuous fin strip is provided with at least one pair of vortex generators. A tube is rotated and linearly displaced while the continuous fin strip with vortex generators is spirally wrapped around the tube.

  18. Disordering transitions in vortex matter: peak effect and phase diagram

    E-Print Network [OSTI]

    Scalettar, Richard T.

    Disordering transitions in vortex matter: peak effect and phase diagram C.J. Olson a,*, C- order nature of this transition. In YBCO a rapid increase in Jc as a function of magnetic field vortex phase diagram as a function of magnetic field and temperature. For increasing field or temperature

  19. Vortex Lattice Modelling of Winglets on Wind Turbine Blades

    E-Print Network [OSTI]

    Vortex Lattice Modelling of Winglets on Wind Turbine Blades Mads Døssing Risø-R-1621(EN) Risø 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

  20. Conveying Cycle-Time Analysis in Pneumatic Conveying: A Study of Relationship between Batching & Convey Cycles in Powder & Bulk Handling Systems

    E-Print Network [OSTI]

    Aghdaie, Bahman

    2008-12-19

    The purpose of this project is to develop methods for calculating the instantaneous convey rates for pneumatic conveying systems. Process and systems engineers are often faced with the question of calculating or verifying the required conveying...

  1. Vortex lattice for a holographic superconductor

    E-Print Network [OSTI]

    Kengo Maeda; Makoto Natsuume; Takashi Okamura

    2009-12-17

    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.

  2. Electron vortex beams in a magnetic field and spin filter

    E-Print Network [OSTI]

    Debashree Chowdhury; Banasri Basu; Pratul Bandyopadhyay

    2015-02-25

    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.

  3. Dynamics of Magnetized Vortex Tubes in the Solar Chromosphere

    E-Print Network [OSTI]

    Kitiashvili, I N; Mansour, N N; Wray, A A

    2012-01-01

    We use 3D radiative MHD simulations to investigate the formation and dynamics of small-scale (less than 0.5 Mm in diameter) vortex tubes spontaneously generated by turbulent convection in quiet-Sun regions with initially weak mean magnetic fields. The results show that the vortex tubes penetrate into the chromosphere and substantially affect the structure and dynamics of the solar atmosphere. The vortex tubes are mostly concentrated in intergranular lanes and are characterized by strong (near sonic) downflows and swirling motions that capture and twist magnetic field lines, forming magnetic flux tubes that expand with height and which attain magnetic field strengths ranging from 200 G in the chromosphere to more than 1 kG in the photosphere. We investigate in detail the physical properties of these vortex tubes, including thermodynamic properties, flow dynamics, and kinetic and current helicities, and conclude that magnetized vortex tubes provide an important path for energy and momentum transfer from the con...

  4. Multistage interaction of a shock wave and a strong vortex Shuhai Zhanga

    E-Print Network [OSTI]

    Zhang, Yong-Tao

    tube, it traveled back toward the vortex and the interaction between the shock and the vortex tookMultistage interaction of a shock wave and a strong vortex Shuhai Zhanga China Aerodynamics; published online 8 November 2005 The interaction between a shock wave and a strong vortex is simulated

  5. The effect of stoichiometry on vortex flame interactions

    SciTech Connect (OSTI)

    Bell, John B.; Brown, Nancy J.; Day, Marcus S.; Frenklach, Michael; Grcar, Joseph F.; Tonse, Shaheen R.

    1999-12-01

    The interaction of a vortex pair with a premixed flame serves as an important prototype for premixed turbulent combustion. In this study, the authors investigate the interaction of a counter-rotating vortex pair with an initially flat premixed methane flame. The authors focus on characterizing the mechanical nature of the flame-vortex interaction and on the features of the interaction strongly affected by fuel equivalence ratio. The authors compare computational solutions obtained using a time-dependent, two-dimensional adaptive low Mach number combustion algorithm that incorporates GRI-Mech 1.2 for the chemistry, thermodynamics and transport of the chemical species. The authors find that the circulation around the vortex scours gas from the preheat zone in front of the flame, making the interaction extremely sensitive to equivalence ratio. For nearly stoichiometric cases, the peak mole fraction of CH across the flame is relatively insensitive to the vortex whereas for richer flames they observe a substantial and rapid decline in the peak CH mole fraction, commencing early in the flame-vortex interaction. The peak concentration of HCO is found to correlate, in both space and time, with the peak heat release across a broad range of equivalence ratios. The model also predicts a measurable increase in C{sub 2}H{sub 2} as a result of interaction with the vortex, and a marked increase in the low temperature chemistry activity.

  6. Ferroelectric nanostructure having switchable multi-stable vortex states

    DOE Patents [OSTI]

    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)

    2009-09-22

    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.

  7. Crystalline Scaling Geometries from Vortex Lattices

    E-Print Network [OSTI]

    Ning Bao; Sarah Harrison

    2013-06-25

    We study magnetic geometries with Lifshitz and/or hyperscaling violation exponents (both with a hard wall cutoff in the IR and a smooth black brane horizon) which have a complex scalar field which couples to the magnetic field. The complex scalar is unstable to the production of a vortex lattice in the IR. The lattice is a normalizable mode which is relevant (i.e. grows into the IR.) When one considers linearized backreaction of the lattice on the metric and gauge field, the metric forms a crystalline structure. We analyze the scaling of the free energy, thermodynamic entropy, and entanglement in the lattice phase and find that in the smeared limit, the leading order correction to thermodynamic properties due to the lattice has the scaling behavior of a theory with a hyperscaling violation exponent between 0 and 1, indicating a flow to an effectively lower-dimensional theory in the deep IR.

  8. Fuel injection of coal slurry using vortex nozzles and valves

    DOE Patents [OSTI]

    Holmes, Allen B. (Rockville, MD)

    1989-01-01

    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.

  9. Riemannian geometrical constraints on magnetic vortex filaments in plasmas

    E-Print Network [OSTI]

    L. C. Garcia de Andrade

    2005-10-16

    Two theorems on the Riemannian geometrical constraints on vortex magnetic filaments acting as dynamos in (MHD) flows are presented. The use of Gauss-Mainard-Codazzi equations allows us to investigate in detail the influence of curvature and torsion of vortex filaments in the MHD dynamos. This application follows closely previous applications to Heisenberg spin equation to the investigations in magnetohydrostatics given by Schief (Plasma Physics J. 10, 7, 2677 (2003)). The Lorentz force on vortex filaments are computed and the ratio between the forces along different directions are obtained in terms of the ratio between the corresponding magnetic fields which equals also the ratio between the Frenet torsion and vortex line curvature. A similar relation between Lorentz forces, magnetic fields and twist, which is proportional to total torsion integral has been obtained by Ricca (Fluid Dyn. Res. 36,319 (2005)) in the case of inflexional desiquilibrium of magnetic flux-tubes. This is due to the fact that the magnetic vortex lines are a limit case of the magnetic flux-tubes when the lenght of the tube is much greater than the radius of the tube. Magnetic helicity equation of the filament allows us again to determine the magnetic fields ratio from Frenet curvature and torsion of the vortex lines.

  10. Alleviation of fuselage form drag using vortex flows: Final report

    SciTech Connect (OSTI)

    Wortman, A.

    1987-09-15

    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.

  11. Vortex precession frequency and its amplitude-dependent shift in cylindrical nanomagnets

    SciTech Connect (OSTI)

    Metlov, Konstantin L.

    2013-12-14

    Frequency of free magnetic vortex precession in circular soft ferromagnetic nano-cylinders (magnetic dots) of various sizes is an important parameter, used in design of spintronic devices (such as spin-torque microwave nano-oscillators) and characterization of magnetic nanostructures. Here, using a recently developed collective-variable approach to non-linear dynamics of magnetic textures in planar nano-magnets, this frequency and its amplitude-dependent shift are computed analytically and plotted for the full range of cylinder geometries. The frequency shift is positive in large planar dots, but becomes negative in smaller and more elongated ones. At certain dot dimensions, a zero frequency shift is realized, which can be important for enhancing frequency stability of magnetic nano-oscillators.

  12. Vortex in a relativistic perfect isentropic fluid and Nambu Goto dynamics

    E-Print Network [OSTI]

    B. Boisseau

    1999-11-26

    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

  13. Vortex life cycles in two-and three-layer quasi-geostrophic models 

    E-Print Network [OSTI]

    Fox, Amanda Katherine

    2000-01-01

    regimes with jets has occurred. This research attempted to first determine the typical lifetime of a vortex, with considerations of its birth, evolution, and cessation. A vortex census was also performed in an attempt to describe the life cycle...

  14. Wave–vortex interactions in the nonlinear Schrödinger equation

    SciTech Connect (OSTI)

    Guo, Yuan Bühler, Oliver

    2014-02-15

    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.

  15. Membrane stabilizer

    DOE Patents [OSTI]

    Mingenbach, W.A.

    1988-02-09

    A device is provided for stabilizing a flexible membrane secured within a frame, wherein a plurality of elongated arms are disposed radially from a central hub which penetrates the membrane, said arms imposing alternately against opposite sides of the membrane, thus warping and tensioning the membrane into a condition of improved stability. The membrane may be an opaque or translucent sheet or other material. 10 figs.

  16. The Effects of Wind Tunnel Walls on the Near-field Behavior of a Wingtip Vortex

    E-Print Network [OSTI]

    Hu, Hui

    /vortex interaction on helicopter blades can impact performance and cause undesirable noise and vibration. Vortex completely. This method was applied to investigate the effects of the angle of attack of the test wing vortex structures on dynamics of towed vehicles, tail buffeting, and icing arrays. Blade

  17. Vortex Rings in Bio-inspired and Biological Jet Propulsion Paul S. Krueger1, a

    E-Print Network [OSTI]

    Horth, Lisa

    of the latter, vortex rings are generated by the transient ejection of a jet from a tube or orifice, which leadsVortex Rings in Bio-inspired and Biological Jet Propulsion Paul S. Krueger1, a , Ali A. Moslemi1,b@odu.edu, e wstewart@uci.edu Keywords: Vortex rings, pulsed jets, propulsion, thrust, propulsive efficiency

  18. Vortex pinning in super-conductivity as a rate-independent process

    E-Print Network [OSTI]

    Mielke, Alexander

    : R the magnetic field perpendicular to the plane. The vortex tube density : R is related to ~H via for this case. The modeling assumption in [Cha00] is now that the vortex tubes will not move if the modulus the conservation of the vortex-tube density which is driven by the current J. The second line contains

  19. PHYSICAL REVIEW E 78, 036304 2008 Variational principle in dynamics of a vortex ...lament

    E-Print Network [OSTI]

    Berdichevsky, Victor

    A vortex ...lament is a thin tube such that vorticity is negligible in a vicinity of this tube while insidePHYSICAL REVIEW E 78, 036304 2008 Variational principle in dynamics of a vortex ...lament Victor L in dynamics of vortex ...lament Victor L. Berdichevsky Mechanical Engineering, Wayne State University, Detroit

  20. COLLISIONS OF VORTEX FILAMENT PAIRS VALERIA BANICA, ERWAN FAOU, AND EVELYNE MIOT

    E-Print Network [OSTI]

    Faou, Erwan

    COLLISIONS OF VORTEX FILAMENT PAIRS VALERIA BANICA, ERWAN FAOU, AND EVELYNE MIOT Abstract. We consider the problem of collisions of vortex filaments for a model introduced by Klein, Majda and Damodaran [KMD95] and Zakharov [Z88, Z99] to describe the interaction of almost parallel vortex filaments

  1. Ubiquitous Solar Eruptions Driven by Magnetized Vortex Tubes

    E-Print Network [OSTI]

    Kitiashvili, I N; Lele, S K; Mansour, N N; Wray, A A

    2013-01-01

    The solar surface is covered by high-speed jets transporting mass and energy into the solar corona and feeding the solar wind. The most prominent of these jets have been known as spicules. However, the mechanism initiating these eruptions events is still unknown. Using realistic numerical simulations we find that small-scale eruptions are produced by ubiquitous magnetized vortex tubes generated by the Sun's turbulent convection in subsurface layers. The swirling vortex tubes (resembling tornadoes) penetrate into the solar atmosphere, capture and stretch background magnetic field, and push surrounding material up, generating quasiperiodic shocks. Our simulations reveal a complicated high-speed flow patterns, and thermodynamic and magnetic structure in the erupting vortex tubes. We found that the eruptions are initiated in the subsurface layers and are driven by the high-pressure gradients in the subphotosphere and photosphere, and by the Lorentz force in the higher atmosphere layers.

  2. Optical vortex driven charge current loop and optomagnetism in fullerenes

    E-Print Network [OSTI]

    Wätzel, Jonas; Schäffer, Alexander; Berakdar, Jamal

    2016-01-01

    Endohedral molecular magnets, e.g. as realized in fullerenes containing $\\rm DySc_{2}N$, are promising candidates for molecular electronics and quantum information processing. For their functionalization an ultrafast local magnetization control is essential. Using full ab-initio quantum chemistry calculations we predict the emergence of charge current loops in fullerenes with an associated orbital magnetic moment upon irradiation with weak light vortex pulses that transfer orbital angular momentum. The generated current is controllable by the frequency, the vortex topological charge, and the intensity of the light. Numerical and analytical results show that an ultraviolet vortex femtosecond pulse with an intensity $\\sim10^{13}$ W/cm$^2$ generates non-invasively nA unidirectional surface current with an associated magnetic field of hundreds $\\mu$T at the center of the fullerene.

  3. Low Head, Vortex Induced Vibrations River Energy Converter

    SciTech Connect (OSTI)

    Bernitsas, Michael B.; Dritz, Tad

    2006-06-30

    Vortex Induced Vibrations Aquatic Clean Energy (VIVACE) is a novel, demonstrated approach to extracting energy from water currents. This invention is based on a phenomenon called Vortex Induced Vibrations (VIV), which was first observed by Leonardo da Vinci in 1504AD. He called it ‘Aeolian Tones.’ For decades, engineers have attempted to prevent this type of vibration from damaging structures, such as offshore platforms, nuclear fuel rods, cables, buildings, and bridges. The underlying concept of the VIVACE Converter is the following: Strengthen rather than spoil vortex shedding; enhance rather than suppress VIV; harness rather than mitigate VIV energy. By maximizing and utilizing this unique phenomenon, VIVACE takes this “problem” and successfully transforms it into a valuable resource for mankind.

  4. Small Winding-Number Expansion: Vortex Solutions at Critical Coupling

    E-Print Network [OSTI]

    Keisuke Ohashi

    2015-07-22

    We study an axially symmetric solution of a vortex in the Abelian-Higgs model at critical coupling in detail. Here we propose a new idea for a perturbative expansion of a solution, where the winding number of a vortex is naturally extended to be a real number and the solution is expanded with respect to it around its origin. We test this idea on three typical constants contained in the solution and confirm that this expansion works well with the help of the Pad\\'e approximation. For instance, we analytically reproduce the value of the scalar charge of the vortex with an error of $O(10^{-6})$. This expansion is also powerful even for large winding numbers.

  5. Small Winding-Number Expansion: Vortex Solutions at Critical Coupling

    E-Print Network [OSTI]

    Keisuke Ohashi

    2015-09-01

    We study an axially symmetric solution of a vortex in the Abelian-Higgs model at critical coupling in detail. Here we propose a new idea for a perturbative expansion of a solution, where the winding number of a vortex is naturally extended to be a real number and the solution is expanded with respect to it around its origin. We test this idea on three typical constants contained in the solution and confirm that this expansion works well with the help of the Pad\\'e approximation. For instance, we analytically reproduce the value of the scalar charge of the vortex with an error of $O(10^{-6})$. This expansion is also powerful even for large winding numbers.

  6. Small Winding-Number Expansion: Vortex Solutions at Critical Coupling

    E-Print Network [OSTI]

    Ohashi, Keisuke

    2015-01-01

    We study an axially symmetric solution of a vortex in the Abelian-Higgs model at critical coupling in detail. Here we propose a new idea for a perturbative expansion of a solution, where the winding number of a vortex is naturally extended to be a real number and the solution is expanded with respect to it around its origin. We test this idea on three typical constants contained in the solution and confirm that this expansion works well with the help of the Pad\\'e approximation. For instance, we analytically reproduce the value of the scalar charge of the vortex with an error of $O(10^{-6})$. This expansion is also powerful even for large winding numbers.

  7. Exploiting lens aberrations to create electron vortex beams

    E-Print Network [OSTI]

    L. Clark; A. Béché; G. Guzzinati; A. Lubk; M. Mazilu; R. Van Boxem; J. Verbeeck

    2013-07-18

    A model for a new electron vortex beam production method is proposed and experimentally demonstrated. The technique calls on the controlled manipulation of the degrees of freedom of the lens aberrations to achieve a helical phase front. These degrees of freedom are accessible by using the corrector lenses of a transmission electron microscope. The vortex beam is produced through a particular alignment of these lenses into a specifically designed astigmatic state and applying an annular aperture in the condensor plane. Experimental results are found to be in good agreement with simulations.

  8. A Non-Abelian Vortex Lattice in Strongly Coupled Systems

    E-Print Network [OSTI]

    Kenny Wong

    2013-10-09

    The AdS/CFT correspondence predicts that background non-abelian magnetic fields induce instabilities in strongly-coupled systems with non-abelian global symmetries. These instabilities lead to the formation of vortex lattices in which the non-abelian currents "antiscreen" the applied magnetic field. From the bulk perspective, this behaviour can be traced to a well-known instability of Yang-Mills theory. We analyse the phase structure of the instability and comment on aspects of the vortex lattice.

  9. Laboratory Analysis of Vortex Dynamics For Shallow Tidal Inlets 

    E-Print Network [OSTI]

    Whilden, Kerri Ann

    2010-10-12

    OF VORTEX DYNAMICS FOR SHALLOW TIDAL INLETS A Thesis by KERRI ANN WHILDEN Submitted to the O ce of Graduate Studies of Texas A&M University in partial ful llment of the requirements for the degree of MASTER OF SCIENCE August 2009 Major Subject: Ocean... Engineering LABORATORY ANALYSIS OF VORTEX DYNAMICS FOR SHALLOW TIDAL INLETS A Thesis by KERRI ANN WHILDEN Submitted to the O ce of Graduate Studies of Texas A&M University in partial ful llment of the requirements for the degree of MASTER OF SCIENCE Approved...

  10. Experimental investigation of magnetic anisotropy in spin vortex discs

    SciTech Connect (OSTI)

    Garraud, N. Arnold, D. P.

    2014-05-07

    We present experimental 2D vector vibrating sample magnetometer measurements to demonstrate the shape anisotropy effects occurring in micrometer-diameter supermalloy spin vortex discs. Measurements made for different disc sizes and orientations confirm the out-of-plane susceptibility is several orders of magnitude smaller than the in-plane susceptibility. These results validate with a high certitude that spin vortices with high diameter to thickness ratio retain in-plane-only magnetization, even when subjected to fields in the out-of-plane direction. These results contribute to further computational simulations of the dynamics of spin vortex structures in colloidal suspensions where external fields may be applied in any arbitrary direction.

  11. Effect of boundary conditions on axial flow in a concentrated vortex core Richard K. Cohn and Manoochehr M. Koochesfahani

    E-Print Network [OSTI]

    Koochesfahani, Manoochehr M.

    of confined flows such as vortex chambers, and swirl separators (e.g., hydrocyclones). More recently

  12. Laser Stabilization

    SciTech Connect (OSTI)

    Hall, John L.; Taubman, Matthew S.; Ye, Jun

    2010-01-01

    This book chapter covers the basics of the field of stabilizing lasers to optical frequency references such as optical cavities and molecular transitions via the application of servo control systems. These discussions are given with reference to the real-life frequency metrology experienced in Hall-Labs (now Ye-Labs), JILA, University of Colorado. The subjects covered include: the basics of control system stability, a discussion of both the theoretical and experimental limitations, an outline of optical cavity susceptibility to environmental noise, and a brief introduction to the use and limitations of molecular transitions as frequency references.

  13. Gap formation and stability in non-isothermal protoplanetary discs

    E-Print Network [OSTI]

    Les, Robert

    2015-01-01

    Several observations of transition discs show lopsided dust-distributions. A potential explanation is the formation of a large-scale vortex acting as a dust-trap at the edge of a gap opened by a giant planet. Numerical models of gap-edge vortices have thus far employed locally isothermal discs, but the theory of this vortex-forming or `Rossby wave' instability was originally developed for adiabatic discs. We generalise the study of planetary gap stability to non-isothermal discs using customised numerical simulations of disc-planet systems where the planet opens an unstable gap. We include in the energy equation a simple cooling function with cooling timescale $t_c=\\beta\\Omega_k^{-1}$, where $\\Omega_k$ is the Keplerian frequency, and examine the effect of $\\beta$ on the stability of gap edges and vortex lifetimes. We find increasing $\\beta$ lowers the growth rate of non-axisymmetric perturbations, and the dominant azimuthal wavenumber $m$ decreases. We find a quasi-steady state consisting of one large-scale, ...

  14. Investigation of Vortex Structures in Gas-Discharge Nonneutral Electron Plasma: IV. Pulse Ejection of Electrons at the mutual interaction of Vortex Structures

    E-Print Network [OSTI]

    Kervalishvili, N A

    2015-01-01

    The results of experimental investigations of the ejection of electrons from gas-discharge nonneutral electron plasma at interaction of vortex structures have been given. The periodical approach of vortex structures causes the ejection of electrons both from the vortex structures themselves and from the adjacent regions of electron sheath to the end cathodes of discharge device. The ejection takes place in the form of short and long pulses following each other. The nature of these pulses and the dynamics of interaction of vortex structures at their approach were studied.

  15. Elliptic vortex patches: coasts and chaos Andrew Crosby

    E-Print Network [OSTI]

    Lebovitz, Norman

    are important for the transport of heat/salt across the Atlantic and, due to their relatively long life-times (O of such ocean vortices as point vortices and analysing their paths around islands or past coastal gaps presented by Ted were that of motion around a pair of islands (see Figure 2a) where the vortex patch might

  16. Vortex Rings in a Stratified Fluid M. M. Scase

    E-Print Network [OSTI]

    Dalziel, Stuart

    in a stratified fluid, are developed. These models include both buoyancy forces and the drag due to the generation to investigate the waves generated by the propagation of the vortex ring, the ring is modelled as a sphere, based for describing these wavefronts is given. The drag due to the generated internal wave field is calculated

  17. WAVE-VORTEX INTERACTIONS IN THE ATMOSPHERE, AND CLIMATE

    E-Print Network [OSTI]

    Al Hanbali, Ahmad

    WAVE-VORTEX INTERACTIONS IN THE ATMOSPHERE, AND CLIMATE PREDICTION Onno Bokhove Numerical Analysis, The Netherlands o.bokhove@math.utwente.nl Abstract Can we construct an accurate atmospheric climate model parcel dynamics, linear modes, balan- ced models, gravity waves, weather and climate prediction

  18. Modified Black Hole with Polar Jet and Vortex

    E-Print Network [OSTI]

    T. Tmmalm

    2001-12-06

    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.

  19. MOI OF PATTERN FORMATION IN THE VORTEX LANDSCAPE

    E-Print Network [OSTI]

    Wijngaarden, Rinke J.

    1081, 1081 HV Amsterdam, The Netherlands RW@NAT.VU.NL Abstract Due to the occurence of punctuations front were reported by Surdeanu et al.[1]. To local vortex density in the type-II YBa2Cu3O7

  20. Numerical Approximation of Vortex Density Evolution in a Superconductor.

    E-Print Network [OSTI]

    Styles, Vanessa

    Numerical Approximation of Vortex Density Evolution in a Superconductor. C.M. Elliott & V. Styles Abstract A #12;nite volume/element approximation of a mean #12;eld model of superconducting vortices in one approximations of a two-dimensional version of the mean #12;eld model of superconducting vortices considered

  1. Planet Embryos in Vortex Wombs Joseph A. Barranco

    E-Print Network [OSTI]

    Marcus, Philip S.

    Planet Embryos in Vortex Wombs Joseph A. Barranco and Philip S. Marcus Dept. of Astronomy gravitating planetesimals, the "build- ing blocks" of planets. One theory is that the dust grains settle into the mid-plane of the protoplane- tary disk (thin, cool disk of gas and dust in orbit around a newly

  2. Biomedical Engineering Correlation Between Vortex Ring Formation and Mitral

    E-Print Network [OSTI]

    Kheradvar, Arash

    was generated during fluid propulsion and that it is maximal for an annulus diameter close to the normal adult typically develop from a jet or slug of fluid ejected from a nozzle. In fluid mechanics, mitral inflow fluid phenomena observed in the left ventricle during diastole is the presence of vortex rings

  3. VORTEX: Design and Implementation of an Interactive Volumetric Display

    E-Print Network [OSTI]

    Subramanian, Sriram

    VORTEX: Design and Implementation of an Interactive Volumetric Display Abstract True 3D display systems like volumetric displays allow generation of autostereoscopic, multi-view 3D content that has real custom volumetric display from easily available components. By building a touch-enabled volumetric

  4. Pressurized water nuclear reactor system with hot leg vortex mitigator

    DOE Patents [OSTI]

    Lau, Louis K. S. (Monroeville, PA)

    1990-01-01

    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.

  5. Magneto-Vortex Dynamo Model in Solar convection zone

    E-Print Network [OSTI]

    Sergey V. Ershkov

    2011-01-06

    Here is presented a new magneto-vortex dynamo model for modeling & predicting of a processes in Solar plasma convection zone. Solar convection zone is located above the level r > 0,6-0,7 R, where R is a Solar radius. A key feature of such a model is that equation of Solar plasma motion as well as equation of magnetic fields evolution - are reduced to Helmholtz's vortex equation, which is up-graded in according with alpha-effect (Coriolis force forms an additional vorticity field or magnetic field due to Sun's differential rotation). Such an additional vorticity or magnetic field are proved to be concentrated at the proper belt in Solar convection zone under the influence of Coriolis force (at the middle latitudes of the Sun in respect to equator). Besides, such an an additional vorticity & magnetic fields are to be the basic sources of well-known phenomena "Maunder's butterfly" diagram.

  6. Highly efficient electron vortex beams generated by nanofabricated phase holograms

    SciTech Connect (OSTI)

    Grillo, Vincenzo; Mafakheri, Erfan; Frabboni, Stefano

    2014-01-27

    We propose an improved type of holographic-plate suitable for the shaping of electron beams. The plate is fabricated by a focused ion beam on a silicon nitride membrane and introduces a controllable phase shift to the electron wavefunction. We adopted the optimal blazed-profile design for the phase hologram, which results in the generation of highly efficient (25%) electron vortex beams. This approach paves the route towards applications in nano-scale imaging and materials science.

  7. Vortex energy and 360 Neel walls in thinfilm

    E-Print Network [OSTI]

    .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

  8. Vortex energy and 360 Neel wall in thinfilm

    E-Print Network [OSTI]

    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

  9. RECTILINEAR VORTEX SHEETS OF INVISCID LIQUID-GAS TWO-PHASE FLOW: LINEAR STABILITY

    E-Print Network [OSTI]

    Wang, Dehua

    sediment transport, geysers, volcanic eruptions, clouds, rain in natural and climate system; mixture of oil and natural gas in extraction tubes of oil exploitation, oil transportation, steam generators, cooling systems- ology in chemical engineering, medical and genetic engineering, bioengineering, and so on. Multi

  10. Langmuir probe diagnostics of an atmospheric pressure, vortex-stabilized nitrogen plasma jet

    SciTech Connect (OSTI)

    Prevosto, L.; Mancinelli, B. R.; Kelly, H.

    2012-09-15

    Langmuir probe measurements in an atmospheric pressure direct current (dc) plasma jet are reported. Sweeping probes were used. The experiment was carried out using a dc non-transferred arc torch with a rod-type cathode and an anode of 5 mm diameter. The torch was operated at a nominal power level of 15 kW with a nitrogen flow rate of 25 Nl min{sup -1}. A flat ion saturation region was found in the current-voltage curve of the probe. The ion saturation current to a cylindrical probe in a high-pressure non local thermal equilibrium (LTE) plasma was modeled. Thermal effects and ionization/recombination processes inside the probe perturbed region were taken into account. Averaged radial profiles of the electron and heavy particle temperatures as well as the electron density were obtained. An electron temperature around 11 000 K, a heavy particle temperature around 9500 K and an electron density of about 4 Multiplication-Sign 10{sup 22} m{sup -3}, were found at the jet centre at 3.5 mm downstream from the torch exit. Large deviations from kinetic equilibrium were found throughout the plasma jet. The electron and heavy particle temperature profiles showed good agreement with those reported in the literature by using spectroscopic techniques. It was also found that the temperature radial profile based on LTE was very close to that of the electrons. The calculations have shown that this method is particularly useful for studying spraying-type plasma jets characterized by electron temperatures in the range 9000-14 000 K.

  11. X-Ray Imaging of the Dynamic Magnetic Vortex Core Deformation

    Broader source: All U.S. Department of Energy (DOE) Office Webpages (Extended Search)

    alloy) revealed a way to easily switch the vortex polarization with a small alternating electrical current, but how the switching actually occurred has remained speculative in...

  12. Equilibrium vortex motion in two- and three-dimensional suprconductors studied with a dc SQUID

    E-Print Network [OSTI]

    Shaw, Timothy J.

    2010-01-01

    is determined by thermal activation between pinning sites.is determined by thermal activation, it is important tothe SQUID washer. Thermal activation of the vortex between

  13. Hummingbirds generate bilateral vortex loops during hovering: evidence from flow visualization

    E-Print Network [OSTI]

    Pournazeri, Sam; Segre, Paolo; Princevac, Marko; Altshuler, Douglas

    2012-01-01

    energetic cost of flight (Rayner and Gordon 1998; Hedenstro¨generates one vortex ring per stroke (Rayner 1979; Ellington1984; Pennycuick 1988; Rayner and Gordon 1998), which would

  14. Stability of a jet in crossflow

    E-Print Network [OSTI]

    Ilak, Miloš; Bagheri, Shervin; Chevalier, Mattias; Henningson, Dan S

    2010-01-01

    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.

  15. Vortex-induced vibration of a circular cylinder with combined in-line and cross-flow motion

    E-Print Network [OSTI]

    Dahl, Jason (Jason Michael)

    2008-01-01

    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 ...

  16. The role of vortex wake dynamics in the flow-induced vibration of tube arrays

    E-Print Network [OSTI]

    Kevlahan, Nicholas

    The role of vortex wake dynamics in the flow-induced vibration of tube arrays N.K.-R. Kevlahan Keywords: Fluid­structure interaction Vortex-induced vibration Tube arrays Potential flow a b s t r a c in the non-resonant flow-induced vibration of periodic tube arrays. This dual approach untangles the effects

  17. Determination of magnetic vortex chirality using lateral spin-valve and Y. Otani

    E-Print Network [OSTI]

    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

  18. Laminar Flow of a Sheared Vortex Crystal: Scars in Flat Geometry M.-Carmen Miguel,1

    E-Print Network [OSTI]

    Miguel-Lopez, Carmen

    Laminar Flow of a Sheared Vortex Crystal: Scars in Flat Geometry M.-Carmen Miguel,1 Adil Mughal,2 November 2010; published 15 June 2011) We consider the laminar flow of a vortex crystal in the Corbino disk geometry. Laminar flow can be induced by thermal fluctuations melting the crystal, but also by shear stress

  19. Resuspension onset and crater erosion by a vortex ring interacting with a particle layer

    E-Print Network [OSTI]

    Dalziel, Stuart

    Resuspension onset and crater erosion by a vortex ring interacting with a particle layer N. Bethke. Fluids 24, 055106 (2012) Conveyor belt effect in the flow through a tube of a viscous fluid with spinning and crater erosion by a vortex ring interacting with a particle layer N. Bethkea) and S. B. Dalziel

  20. Impact of vortex core structure on equftion of motion V.A.Budarin

    E-Print Network [OSTI]

    1 Impact of vortex core structure on equftion of motion V.A.Budarin National Polytechnical-solid hollow and continuous vortex core wall has been examined in this paper. Two other exact solutions derived of thick-walled cylinders and task about the tube rotation. Comparison of the results obtained has been

  1. Mixing characteristics of compressible vortex rings interacting with normal shock waves

    SciTech Connect (OSTI)

    Cetegen, B.M. . Mechanical Engineering Dept.); Hermanson, J.C. )

    1995-01-01

    Current interest in the interaction between compressible vortical flows and shock waves is largely motivated by the need to promote rapid, loss-effective mixing and combustion of hydrogen and hydrocarbon fuels for supersonic combustor applications. The instability mechanisms and mixing enhancement arising from the interaction of a compressible vortex ring with a normal shock wave were studied in a colinear, dual-shock tube. This flow geometry simulates features of the interaction of a shock wave with a jet containing streamwise vorticity, a configuration of significant interest for supersonic combustion applications. Flow visualization and quantitative concentration measurements were performed by planar laser Rayleigh scattering. For a given primary shock strength, interfacial instability is more evident in a weak vortex ring than in a strong vortex ring. In all cases, the identity of the vortex ring is lost after a sufficiently long time of interaction. The probability density function of the mixed fluid changes rapidly from a bimodal distribution to a single peak upon processing by a shock wave. The most probable concentration decreases with time, indicating a rapid increase in mixing and dilution of the vortex fluid. The mixing enhancement is most rapid for the case of a strong vortex ring interacting with a strong shock wave, somewhat slower for a weak vortex ring and a strong shock wave, and significantly slower for the case of a strong vortex ring and a weaker shock wave. These observations are consistent with the earlier numerical predictions.

  2. Comparison of optical vortex detection methods for use with a Shack-Hartmann

    E-Print Network [OSTI]

    Dainty, Chris

    Comparison of optical vortex detection methods for use with a Shack-Hartmann wavefront sensor Kevin of de- tecting optical vortices from Shack-Hartmann wavefront sensor (SHWFS) data, the vortex potential of Shack-Hartmann wavefront sensing," J. Refract. Surg. 17, S573­S577 (2001). 13. J. Notaras and C

  3. A Model of Compressor Blade Row Interaction with Shock Induced Vortex Shedding

    E-Print Network [OSTI]

    Cincinnati, University of

    A Model of Compressor Blade Row Interaction with Shock Induced Vortex Shedding Mark G. Turner". The mid and far spacings represent typical axial gaps found in operational fans and compressors. However behind a stator are modeled. The model is based on a Burger vortex core model for shed vortices

  4. Numerical Simulation of Vortex Pyrolysis Reactors for Condensable Tar Production from Biomass

    E-Print Network [OSTI]

    Miller, Richard S.

    Numerical Simulation of Vortex Pyrolysis Reactors for Condensable Tar Production from Biomass R. S is performed in order to evaluate the performance and optimal operating conditions of vortex pyrolysis reactors particle pyrolysis is coupled with a compressible Reynolds stress transport model for the turbulent reactor

  5. Nanogenerator as an active sensor for vortex capture and ambient wind-velocity detection

    E-Print Network [OSTI]

    Wang, Zhong L.

    efficiently convert the vortex motion in the atmosphere into electricity. Based on the Karman vortex street in wireless environmental monitoring networks. 1. Introduction Self-powered nanosystem is a promising concept for the realization of environmental wireless sensor networks. Due to the enormous demands of distributed nodes

  6. The critical velocity for vortex existence in a two dimensional rotating Bose-Einstein condensate

    E-Print Network [OSTI]

    Ignat, Radu

    The critical velocity for vortex existence in a two dimensional rotating Bose-Einstein condensate-Einstein condensate. It consists in minimizing a Gross-Pitaevskii functional defined in R2 under the unit mass constraint. We estimate the critical rotational speed 1 for vortex existence in the bulk of the condensate

  7. Generalized London free energy for high-Tc vortex lattices Ian Affleck

    E-Print Network [OSTI]

    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

  8. A model for universal time scale of vortex ring formation Kamran Mohseni

    E-Print Network [OSTI]

    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

  9. Modeling bubble-vortex interactions Modeling and simulation of multiple bubble entrainment and interactions with two

    E-Print Network [OSTI]

    Apte, Sourabh V.

    Modeling bubble-vortex interactions Modeling and simulation of multiple bubble entrainment entrainment and interactions with two dimensional vorti- cal flows are preformed using a Discrete Element microbubbles entrained in a traveling vortex tube is studied in detail. The test case resembles the experiments

  10. Electronic states near a quantum fluctuating point vortex in a d-wave superconductor: Dirac fermion theory

    E-Print Network [OSTI]

    -point motion in a d-wave superconductor. The vortex is treated as a point flux tube, carrying fluxElectronic states near a quantum fluctuating point vortex in a d-wave superconductor: Dirac fermion model of the low-energy electronic states in the vicinity of a vortex undergoing quantum zero

  11. Slowing of vortex rings by development of Kelvin waves Robert E. Hershberger, Diogo Bolster, and Russell J. Donnelly*

    E-Print Network [OSTI]

    Bolster, Diogo

    , at least for a straight vortex tube case, results from subjection to a straining field in a planeSlowing of vortex rings by development of Kelvin waves Robert E. Hershberger, Diogo Bolster the slowing of viscous vortex rings. In particular we do so using the concept of drag coefficient, which

  12. Bluff Body Flow Simulation Using a Vortex Element Method

    SciTech Connect (OSTI)

    Anthony Leonard; Phillippe Chatelain; Michael Rebel

    2004-09-30

    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.

  13. Gradient catastrophe and flutter in vortex filament dynamics

    E-Print Network [OSTI]

    B. G. Konopelchenko; G. Ortenzi

    2011-06-02

    Gradient catastrophe and flutter instability in the motion of vortex filament within the localized induction approximation are analyzed. It is shown that the origin if this phenomenon is in the gradient catastrophe for the dispersionless Da Rios system which describes motion of filament with slow varying curvature and torsion. Geometrically this catastrophe manifests as a rapid oscillation of a filament curve in a point that resembles the flutter of airfoils. Analytically it is the elliptic umbilic singularity in the terminology of the catastrophe theory. It is demonstrated that its double scaling regularization is governed by the Painlev\\'e-I equation.

  14. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousandReport) |Administration SavannahMagnetic Vortex Core

  15. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousandReport) |Administration SavannahMagnetic Vortex CoreMagnetic

  16. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousandReport) |Administration SavannahMagnetic Vortex

  17. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousandReport) |Administration SavannahMagnetic VortexMagnetic

  18. 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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration would likeUniverseIMPACTThousandReport) |Administration SavannahMagneticMagnetic Vortex Core

  19. Vortex nozzle for segmenting and transporting metal chips from turning operations

    DOE Patents [OSTI]

    Bieg, L.F.

    1993-04-20

    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.

  20. Flame-vortex interaction driven combustion dynamics in a backward-facing step combustor

    SciTech Connect (OSTI)

    Altay, H. Murat; Speth, Raymond L.; Hudgins, Duane E.; Ghoniem, Ahmed F.

    2009-05-15

    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)

  1. The Relation Between Dry Vortex Merger and Tropical Cyclone Genesis over the Atlantic Ocean

    SciTech Connect (OSTI)

    Chen, Shu-Hua; Liu, Yi-Chin

    2014-10-27

    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.

  2. Venturi/vortex technology for controlling chromium electroplating emissions

    SciTech Connect (OSTI)

    Hay, K.J.; Northrup, J. [Army Construction Engineering Research Labs., Champaign, IL (United States); Heck, S.R. [MSE-HKM, Inc., Butte, MT (United States)

    1997-12-31

    A new technology has been developed to control air emissions from hexavalent chromium electroplating tanks. The venturi/vortex scrubber uses a patented drain assembly to pull plating solution, air with toxic particulates above the solution, and unpopped bubbles of generated gases down with a gravity generated vortex effect. The recirculated plating solution acts as the scrubbing liquid and air agitation is eliminated. Separated gases are passed through a condenser/filter to remove any remaining fumes. The device is almost entirely constructed of CPVC. This device offers several advantages over conventional end-of-pipe systems including significantly lower cost, no wastewater, no extensive ventilation system, and emissions are recycled. The system can be is easily retrofitted to existing tanks, however, a loose fitting tank lid is recommended. A pilot demonstration has been performed at Benet Laboratory, Watervliet, NY (US Army) with a 1,500 gallon chromic acid electroplating tank and 1,500 Amps of applied current. Overall chromium emissions results were 0.00002 mg/Amp-hr, surpassing the stringent California State requirement of 0.006 mg/Amp-hr. Emission prevention by capturing unpopped bubbles is the method in which this system reduces the most emissions. The system met current ambient worker safety standards. Two major improvements are recommended: an increase in gas flow rate through the system and a solution to the system`s sensitivity to the plating solution level.

  3. Decay of helical Kelvin waves on a quantum vortex filament

    SciTech Connect (OSTI)

    Van Gorder, Robert A.

    2014-07-15

    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.

  4. Vortex flow in the technology of radiation wave cracking (RWC)

    E-Print Network [OSTI]

    L. A. Tsoy; V. N. Kolushov; A. G. Komarov; A. N. Tsoy

    2012-09-16

    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.

  5. Energy harvesting using vortex-induced vibrations of tensioned cables

    E-Print Network [OSTI]

    Grouthier, Clement; de Langre, Emmanuel

    2012-01-01

    The development of energy harvesting systems based on fluid/structure interactions is part of the global search for innovative tools to produce renewable energy. In this paper, the possibility to harvest energy from a flow using vortex-induced vibrations (VIV) of a tensioned flexible cable is analyzed. The fluid loading on the vibrating solid and resulting dynamics are computed using an appropriate wake-oscillator model, allowing one to perform a systematic parametric study of the efficiency. The generic case of an elastically-mounted rigid cylinder is first investigated, before considering an infinite cable with two different types of energy harvesting : a uniformly spanwise distributed harvesting and then a periodic distribution of discrete harvesting devices. The maximum harvesting efficiency is of the same order for each configuration and is always reached when the solid body and its wake are in a frequency lock-in state.

  6. Fast chirality reversal of the magnetic vortex by electric current

    SciTech Connect (OSTI)

    Lim, W. L. Liu, R. H.; Urazhdin, S.; Tyliszczak, T.; Erokhin, S. G.; Berkov, D.

    2014-12-01

    The possibility of high-density information encoding in magnetic materials by topologically stable inhomogeneous magnetization configurations such as domain walls, skyrmions, and vortices has motivated intense research into mechanisms enabling their control and detection. While the uniform magnetization states can be efficiently controlled by electric current using magnetic multilayer structures, this approach has proven much more difficult to implement for inhomogeneous states. Here, we report direct observation of fast reversal of magnetic vortex by electric current in a simple planar structure based on a bilayer of spin Hall material Pt with a single microscopic ferromagnetic disk contacted by asymmetric electrodes. The reversal is enabled by a combination of the chiral Oersted field and spin current generated by the nonuniform current distribution in Pt. Our results provide a route for the efficient control of inhomogeneous magnetization configurations by electric current.

  7. Gas turbine engine combustor can with trapped vortex cavity

    DOE Patents [OSTI]

    Burrus, David Louis; Joshi, Narendra Digamber; Haynes, Joel Meier; Feitelberg, Alan S.

    2005-10-04

    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.

  8. Vortex Induced Vibrations of cylinders : experiments in reducing drag force and amplitude of motion

    E-Print Network [OSTI]

    Farrell, David Emmanuel

    2007-01-01

    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 ...

  9. Numerically-based ducted propeller design using vortex lattice lifting line theory

    E-Print Network [OSTI]

    Stubblefield, John M

    2008-01-01

    This thesis used vortex lattice lifting line theory to model an axisymmetrical-ducted propeller with no gap between the duct and the propeller. The theory required to model the duct and its interaction with the propeller ...

  10. Effects of trailing edge flap dynamic deployment on blade-vortex interactions 

    E-Print Network [OSTI]

    Nelson, Carter T.

    1997-01-01

    A theoretical and experimental investigation is undertaken to determine the effects of an actively deployable trailing edge flap on the disturbances created during blade-vortex interactions (BVI). The theoretical model consists of an unsteady panel...

  11. An adaptive mesh method for the simulation of Blade Vortex Interaction 

    E-Print Network [OSTI]

    Kim, Kyu-Sup

    1998-01-01

    An adaptive mesh method for the simulation of parallel ics. Blade Vortex Interaction (BV1) with an active Trailing Edge Flap (TEF) is presented. The two-dimensional 1111-steady problem is solved by a higher order upwind Euler method...

  12. Variability of the polar stratospheric vortex and its impact on surface climate patterns

    E-Print Network [OSTI]

    Sheshadri, Aditi

    2015-01-01

    This thesis investigates various aspects of the variability of the stratospheric polar vortex and the effect of this variability on tropospheric weather and climate patterns on various timescales. In the first part of this ...

  13. Reduced gravity rankine cycle design and optimization with passive vortex phase separation 

    E-Print Network [OSTI]

    Supak, Kevin Robert

    2009-05-15

    turbo machinery, require kilowatts of power and are untested for high vapor flow conditions. The Interphase Transport Phenomena (ITP) laboratory has developed a low-power, passive microgravity vortex phase separator (MVS) which has already proven...

  14. Effect of traveling waves on Vortex-Induced Vibration of long flexible cylinders

    E-Print Network [OSTI]

    Jaiswal, Vivek, Ph. D. Massachusetts Institute of Technology

    2009-01-01

    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 ...

  15. Vortex-induced vibration of flexible cylinders in time-varying flows

    E-Print Network [OSTI]

    Resvanis, Themistocles L

    2014-01-01

    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 ...

  16. Enhancement of vortex induced forces and motion through surface roughness control

    DOE Patents [OSTI]

    Bernitsas, Michael M. (Saline, MI); Raghavan, Kamaldev (Houston, TX)

    2011-11-01

    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).

  17. Lagrangian analysis of fluid transport in empirical vortex ring flows Shawn C. Shadden

    E-Print Network [OSTI]

    Marsden, Jerrold

    Lagrangian analysis of fluid transport in empirical vortex ring flows Shawn C. Shadden Control and Dynamical Systems, California Institute of Technology, Pasadena, California 91125 John O. Dabiri Graduate Aeronautical Laboratories and Bioengineering, California Institute of Technology, Pasadena, California 91125

  18. Explicit mean-field radius for nearly parallel vortex filaments in statistical equilibrium

    E-Print Network [OSTI]

    Timothy D. Andersen; Chjan C. Lim

    2006-11-19

    Geophysical research has focused on flows, such as ocean currents, as two dimensional. Two dimensional point or blob vortex models have the advantage of having a Hamiltonian, whereas 3D vortex filament or tube systems do not necessarily have one, although they do have action functionals. On the other hand, certain classes of 3D vortex models called nearly parallel vortex filament models do have a Hamiltonian and are more accurate descriptions of geophysical and atmospheric flows than purely 2D models, especially at smaller scales. In these ``quasi-2D'' models we replace 2D point vortices with vortex filaments that are very straight and nearly parallel but have Brownian variations along their lengths due to local self-induction. When very straight, quasi-2D filaments are expected to have virtually the same planar density distributions as 2D models. An open problem is when quasi-2D model statistics behave differently than those of the related 2D system and how this difference is manifested. In this paper we study the nearly parallel vortex filament model of Klein, Majda, Damodaran in statistical equilibrium. We are able to obtain a free-energy functional for the system in a non-extensive thermodynamic limit that is a function of the mean square vortex position $R^2$ and solve \\emph{explicitly} for $R^2$. Such an explicit formula has never been obtained for a non-2D model. We compare the results of our formula to a 2-D formula of \\cite{Lim:2005} and show qualitatively different behavior even when we disallow vortex braiding. We further confirm our results using Path Integral Monte Carlo (Ceperley (1995)) \\emph{without} permutations and that the Klein, Majda, Damodaran model's asymptotic assumptions \\emph{are valid} for parameters where these deviations occur.

  19. Vortex in a weakly relativistic Bose gas at zero temperature and relativistic fluid approximation

    E-Print Network [OSTI]

    B. Boisseau

    2004-09-14

    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.

  20. Investigation of Vortex Structures in Gas-Discharge Nonneutral Electron Plasma: III. Pulse Ejection of Electrons at the Formation and Radial Oscillations of Vortex Structure

    E-Print Network [OSTI]

    Kervalishvili, N A

    2015-01-01

    The results of experimental investigations of electron ejection from gas-discharge nonneutral electron plasma at the formation and radial oscillations of vortex structure have been presented. The electrons are injected from the vortex structure and the adjacent region of electron sheath in the form of pulses the duration and periodicity of which are determined by the processes of evolution and dynamics of this structure. The possible mechanisms of pulse ejection of electrons are considered. The influence of electron ejection on other processes in discharge electron sheath is analyzed.

  1. The internal structure of a vortex in a two-dimensional superfluid with long healing length and its implications

    SciTech Connect (OSTI)

    Klein, Avraham; Aleiner, Igor L.; Agam, Oded

    2014-07-15

    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.

  2. Effects of Combustion-Induced Vortex Breakdown on Flashback Limits of Syngas-Fueled Gas Turbine Combustors

    SciTech Connect (OSTI)

    Ahsan Choudhuri

    2011-03-31

    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.

  3. Casimir force between vortex matter in anisotropic and layered superconductors 

    E-Print Network [OSTI]

    Katzgraber, Helmut G.; Buchler, HP; Blatter, G.

    1999-01-01

    Squeeze film dampers (SFDs) provide viscous damping to attenuate excessive vibrations and enhance system stability in turbomachinery. SFDs are of special importance in aircraft engines which use rolling element support ...

  4. RCRA facility stabilization initiative

    SciTech Connect (OSTI)

    Not Available

    1995-02-01

    The RCRA Facility Stabilization Initiative was developed as a means of implementing the Corrective Action Program`s management goals recommended by the RIS for stabilizing actual or imminent releases from solid waste management units that threaten human health and the environment. The overall goal of stabilization is to, as situations warrant, control or abate threats to human health and/or the environment from releases at RCRA facilities, and/or to prevent or minimize the further spread of contamination while long-term remedies are pursued. The Stabilization initiative is a management philosophy and should not be confused with stabilization technologies.

  5. Feedback stabilization initiative

    SciTech Connect (OSTI)

    NONE

    1997-06-01

    Much progress has been made in attaining high confinement regimes in magnetic confinement devices. These operating modes tend to be transient, however, due to the onset of MHD instabilities, and their stabilization is critical for improved performance at steady state. This report describes the Feedback Stabilization Initiative (FSI), a broad-based, multi-institutional effort to develop and implement methods for raising the achievable plasma betas through active MHD feedback stabilization. A key element in this proposed effort is the Feedback Stabilization Experiment (FSX), a medium-sized, national facility that would be specifically dedicated to demonstrating beta improvement in reactor relevant plasmas by using a variety of MHD feedback stabilization schemes.

  6. Dynamics of a relativistic Rankine vortex for a two-constituent superfluid in a weak perturbation of cylindrical symmetry

    E-Print Network [OSTI]

    B. Boisseau

    1999-01-18

    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.

  7. MICROMAGNETIC STUDIES OF THE TRANSITION BETWEEN VORTEX AND SINGLE-DOMAIN STATES IN SUB-100 NM NANODOTS 

    E-Print Network [OSTI]

    King, Andrew

    2012-04-26

    20 40 60 80 100 120 140 To ta l E ne rg y (e V ) Vortex-­?Core Posi2on (nm) Total Energy vs. Vortex-­?Core Posi2on 65 nm Diameter Iron Dot 0 kOe 0.5 kOe 17... B ar ri er (e V ) Applied Field (kOe) Energy Barriers vs. Applied Field 40 nm Diameter Iron Dot Vortex Annihila:on Vortex Nuclea:on 21 FIG. 8. Energy barriers plotted versus applied...

  8. Ferromagnetic and antiferromagnetic order in bacterial vortex lattices

    E-Print Network [OSTI]

    Hugo Wioland; Francis G. Woodhouse; Jörn Dunkel; Raymond E. Goldstein

    2015-11-16

    Despite their inherent non-equilibrium nature, living systems can self-organize in highly ordered collective states that share striking similarities with the thermodynamic equilibrium phases of conventional condensed matter and fluid systems. Examples range from the liquid-crystal-like arrangements of bacterial colonies, microbial suspensions and tissues to the coherent macro-scale dynamics in schools of fish and flocks of birds. Yet, the generic mathematical principles that govern the emergence of structure in such artificial and biological systems are elusive. It is not clear when, or even whether, well-established theoretical concepts describing universal thermostatistics of equilibrium systems can capture and classify ordered states of living matter. Here, we connect these two previously disparate regimes: Through microfluidic experiments and mathematical modelling, we demonstrate that lattices of hydrodynamically coupled bacterial vortices can spontaneously organize into distinct phases of ferro- and antiferromagnetic order. The preferred phase can be controlled by tuning the vortex coupling through changes of the inter-cavity gap widths. The emergence of opposing order regimes is tightly linked to the existence of geometry-induced edge currents, reminiscent of those in quantum systems. Our experimental observations can be rationalized in terms of a generic lattice field theory, suggesting that bacterial spin networks belong to the same universality class as a wide range of equilibrium systems.

  9. Vortex generation in protoplanetary disks with an embedded giant planet

    E-Print Network [OSTI]

    M. de Val-Borro; P. Artymowicz; G. D'Angelo; A. Peplinski

    2007-06-21

    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 $\

  10. A Robust Numerical Method for Integration of Point-Vortex Trajectories in Two Dimensions

    E-Print Network [OSTI]

    Spencer A. Smith; Bruce M. Boghosian

    2010-11-19

    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.

  11. Transition between vortex rings and MAP solutions for electrically charged magnetic solutions

    SciTech Connect (OSTI)

    Wong, Khai-Ming; Soltanian, Amin; Teh, Rosy

    2014-03-05

    We consider the bifurcation and transition of axially symmetric monopole-antimonopole pair (MAP) and vortex ring solutions in the presence of electric charge for the SU(2) Yang-Mills-Higgs field theory. Here we investigate the properties of MAP/vortex ring solutions with n = 3,? = 0.65, for different Higgs field strength ?. For ? < 4.93, there is only one fundamental branch of vortex ring solution, but at the critical value of ?{sub b} = 4.93, branching happens and 2 sets of new solutions appeared. The new branch with less energy is a full MAP solution while the branch with higher energy contains MAP at the beginning and separation between poles of MAP on the z-axis reduces gradually and at another critical value of ?{sub t} = 14.852, they merge together at z = 0. Beyond this point the solutions change to the vortex ring solutions and a transitions between MAP and vortex ring solutions happens at this branch.

  12. Bow-wave-like hydraulic jump and horseshoe vortex around an obstacle in a supercritical open channel flow

    E-Print Network [OSTI]

    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

  13. A vortex level set method for the two-way coupling of an incompressible fluid with colliding rigid bodies

    E-Print Network [OSTI]

    Cottet, Georges-Henri

    in a non laminar flow. Here we consider a different approach. The fluid­ solid system is considered rights reserved. Keywords: Incompressible flow; Fluid­solid interaction; Vortex method; Level set methodA vortex level set method for the two-way coupling of an incompressible fluid with colliding rigid

  14. Effect of tube spacing on the vortex shedding characteristics of laminar flow past an inline tube array: A numerical study

    E-Print Network [OSTI]

    Luo, Xiaoyu

    Effect of tube spacing on the vortex shedding characteristics of laminar flow past an inline tube the tubes. Complex flow dynamic phenomena such as reattachment of shear layers, in- duced separation, vortex Accepted 27 October 2008 Available online 14 November 2008 a b s t r a c t The effect of tube spacing

  15. Two-dimensional model problem to explain counter-rotating vortex pair formation in a transverse jet

    E-Print Network [OSTI]

    Mahesh, Krishnan

    Two-dimensional model problem to explain counter-rotating vortex pair formation in a transverse jet A two-dimensional model problem is used to study the evolution of the cross section of a transverse jet and the counter-rotating vortex pair CVP . The solution to the model problem shows deformation of the jet similar

  16. Electron trapping by a current vortex F. Bentosela, a;b P. Exner, c;d and V.A. Zagrebnov a;b

    E-Print Network [OSTI]

    simpler example involves a Pauli electron interacting with a flux tube modelling a vortex magnetic fieldElectron trapping by a current vortex F. Bentosela, a;b P. Exner, c;d and V.A. Zagrebnov a;b a with the magnetic field due to an electric current forming a localized rotationally symmetric vortex. We show

  17. arXiv:cond-mat/0606001v222Jul2006 Electronic states near a quantum fluctuating point vortex in a d-wave superconductor

    E-Print Network [OSTI]

    -wave superconductor. The vortex is treated as a point flux tube, carrying flux of an auxiliary U(1) gauge fieldarXiv:cond-mat/0606001v222Jul2006 Electronic states near a quantum fluctuating point vortex in a d energy electronic states in the vicinity of a vortex under- going quantum zero-point motion in a d

  18. Role of the Vortex-Core Energy on the Berezinskii-Kosterlitz-Thouless Transition in Thin Films of NbN

    E-Print Network [OSTI]

    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

  19. Magnetic monopole versus vortex as gauge-invariant topological objects for quark confinement

    E-Print Network [OSTI]

    Kondo, Kei-Ichi; Shinohara, Toru; Shibata, Akihiro; Kato, Seikou

    2015-01-01

    First, we give a gauge-independent definition of chromomagnetic monopoles in $SU(N)$ Yang-Mills theory which is derived through a non-Abelian Stokes theorem for the Wilson loop operator. Then we discuss how such magnetic monopoles can give a nontrivial contribution to the Wilson loop operator for understanding the area law of the Wilson loop average. Next, we discuss how the magnetic monopole condensation picture are compatible with the vortex condensation picture as another promising scenario for quark confinement. We analyze the profile function of the magnetic flux tube as the non-Abelian vortex solution of $U(N)$ gauge-Higgs model, which is to be compared with numerical simulations of the $SU(N)$ Yang-Mills theory on a lattice. This analysis gives an estimate of the string tension based on the vortex condensation picture, and possible interactions between two non-Abelian vortices.

  20. Spectro-Polarimetric Properties of Small-Scale Plasma Eruptions Driven by Magnetic Vortex Tubes

    E-Print Network [OSTI]

    Kitiashvili, Irina N

    2014-01-01

    Highly turbulent nature of convection on the Sun causes strong multi-scale interaction of subsurface layers with the photosphere and chromosphere. According to realistic 3D radiative MHD numerical simulations ubiquitous small-scale vortex tubes are generated by turbulent flows below the visible surface and concentrated in the intergranular lanes. The vortex tubes can capture and amplify magnetic field, penetrate into chromospheric layers and initiate quasi-periodic flow eruptions that generates Alfv\\'enic waves, transport mass and energy into the solar atmosphere. The simulations revealed high-speed flow patterns, and complicated thermodynamic and magnetic structures in the erupting vortex tubes. The spontaneous eruptions are initiated and driven by strong pressure gradients in the near-surface layers, and accelerated by the Lorentz force in the low chromosphere. In this paper, the simulation data are used to further investigate the dynamics of the eruptions, their spectro-polarimetric characteristics for the...

  1. Magnetic monopole versus vortex as gauge-invariant topological objects for quark confinement

    E-Print Network [OSTI]

    Kei-Ichi Kondo; Takaaki Sasago; Toru Shinohara; Akihiro Shibata; Seikou Kato

    2015-08-08

    First, we give a gauge-independent definition of chromomagnetic monopoles in $SU(N)$ Yang-Mills theory which is derived through a non-Abelian Stokes theorem for the Wilson loop operator. Then we discuss how such magnetic monopoles can give a nontrivial contribution to the Wilson loop operator for understanding the area law of the Wilson loop average. Next, we discuss how the magnetic monopole condensation picture are compatible with the vortex condensation picture as another promising scenario for quark confinement. We analyze the profile function of the magnetic flux tube as the non-Abelian vortex solution of $U(N)$ gauge-Higgs model, which is to be compared with numerical simulations of the $SU(N)$ Yang-Mills theory on a lattice. This analysis gives an estimate of the string tension based on the vortex condensation picture, and possible interactions between two non-Abelian vortices.

  2. Vortex combustor for low NOx emissions when burning lean premixed high hydrogen content fuel

    DOE Patents [OSTI]

    Steele, Robert C. (Woodinville, WA); Edmonds, Ryan G. (Renton, WA); Williams, Joseph T. (Kirkland, WA); Baldwin, Stephen P. (Winchester, MA)

    2009-10-20

    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.

  3. Shear Banding and Spatiotemporal Oscillations in Vortex Matter in Nanostructured Superconductors

    E-Print Network [OSTI]

    C. Reichhardt; C. J. Olson Reichhardt

    2009-12-16

    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.

  4. Reduction of vortex induced forces and motion through surface roughness control

    DOE Patents [OSTI]

    Bernitsas, Michael M; Raghavan, Kamaldev

    2014-04-01

    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.

  5. Random Vortex-Street Model for a Self-Similar Plane Turbulent Jet

    E-Print Network [OSTI]

    Victor L'vov; Anna Pomyalov; Itamar Procaccia; Rama Govindarajan

    2008-03-18

    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.

  6. Vortex combustor for low NOX emissions when burning lean premixed high hydrogen content fuel

    DOE Patents [OSTI]

    Steele, Robert C; Edmonds, Ryan G; Williams, Joseph T; Baldwin, Stephen P

    2012-11-20

    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.

  7. Single-vortex pinning and penetration depth in superconducting NdFeAsO1-xFx

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Zhang, Jessie T.; Kim, Jeehoon; Huefner, Magdalena; Ye, Cun; Kim, Stella; Canfield, Paul C.; Prozorov, Ruslan; Auslaender, Ophir M.; Hoffman, Jennifer E.

    2015-10-12

    We use a magnetic force microscope (MFM) to investigate single vortex pinning and penetration depth in NdFeAsO1-xFx, one of the highest-Tc iron-based superconductors. In fields up to 20 Gauss, we observe a disordered vortex arrangement, implying that the pinning forces are stronger than the vortex-vortex interactions. We measure the typical force to depin a single vortex, Fdepin ? 4.5 pN, corresponding to a critical current up to Jc ? 7×105 A/cm2. As a result, our MFM measurements allow the first local and absolute determination of the superconducting in-plane penetration depth in NdFeAsO1-xFx, ?ab = 320 ± 60 nm, which ismore »larger than previous bulk measurements.« less

  8. Stabilized radio frequency quadrupole

    DOE Patents [OSTI]

    Lancaster, Henry D. (Orinda, CA); Fugitt, Jock A. (Berkeley, CA); Howard, Donald R. (Danville, CA)

    1984-01-01

    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.

  9. Relativistic Electron Vortex Beams: Angular Momentum and Spin-Orbit Interaction

    E-Print Network [OSTI]

    Konstantin Y. Bliokh; Mark R. Dennis; Franco Nori

    2011-09-11

    Motivated by the recent discovery of electron vortex beams carrying orbital angular momentum (AM), we construct exact Bessel-beam solutions of the Dirac equation. They describe relativistic and nonparaxial corrections to the scalar electron beams. We describe the spin and orbital AM of the electron with Berry-phase corrections and predict the intrinsic spin-orbit coupling in free space. This can be observed as a spin-dependent probability distribution of the focused electron vortex beams. Moreover, the magnetic moment is calculated, which shows different $g$-factors for spin and orbital AM and also contains the Berry-phase correction.

  10. VORTEX CREEP AGAINST TOROIDAL FLUX LINES, CRUSTAL ENTRAINMENT, AND PULSAR GLITCHES

    SciTech Connect (OSTI)

    Gügercino?lu, Erbil; Alpar, M. Ali E-mail: alpar@sabanciuniv.edu

    2014-06-10

    A region of toroidally oriented quantized flux lines must exist in the proton superconductor in the core of the neutron star. This region will be a site of vortex pinning and creep. Entrainment of the neutron superfluid with the crustal lattice leads to a requirement of superfluid moment of inertia associated with vortex creep in excess of the available crustal moment of inertia. This will bring about constraints on the equation of state. The toroidal flux region provides the moment of inertia necessary to complement the crust superfluid with postglitch relaxation behavior fitting the observations.

  11. Deep sub-nanosecond reversal of vortex cores confined in a spin-wave potential well

    SciTech Connect (OSTI)

    Dong, Xinwei; Wang, Zhenyu; Wang, Ruifang, E-mail: wangrf@xmu.edu.cn [Department of Physics and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen 361005 (China)

    2014-03-17

    A spin-wave potential well is created in a permalloy nanodisk by setting up a cylindrical cavity in the center of the sample. We then apply a single-harmonic external magnetic field perpendicular to the disk plane to switch the vortex polarity of the sample. Our micromagnetic numerical studies establish that the effective spin-wave confinement by the potential well leads to much stronger magnetization oscillation in the sample. Therefore, the vortex core can be reversed well below 200 ps and over a wide range of field frequency. Our findings present an additional efficient means for ultrafast switching of magnetic vortices.

  12. Vortex reconnections in atomic condensates at finite temperature A. J. Allen1

    E-Print Network [OSTI]

    Zuccher, Simone

    superfluid turbu- lence, a phenomenon recently also reported in trapped atomic Bose­Einstein condensates, vortex dynamics, quantum turbulence, Bose-Einstein condensates, Superfluid He In classical hydrodynamics 3 He and atomic Bose­Einstein condensates (BECs) is currently debated. For example, one would like

  13. Detection of vortex tubes in solar granulation from observations with Sunrise

    E-Print Network [OSTI]

    Steiner, O; Gonzalez, N Bello; Nutto, Ch; Rezaei, R; Pillet, V Martinez; Navarro, J A Bonet; Iniesta, J C del Toro; Domingo, V; Solanki, S K; Knolker, M; Schmidt, W; Barthol, P; Gandorfer, A

    2010-01-01

    We have investigated a time series of continuum intensity maps and corresponding Dopplergrams of granulation in a very quiet solar region at the disk center, recorded with the Imaging Magnetograph eXperiment (IMaX) on board the balloon-borne solar observatory Sunrise. We find that granules frequently show substructure in the form of lanes composed of a leading bright rim and a trailing dark edge, which move together from the boundary of a granule into the granule itself. We find strikingly similar events in synthesized intensity maps from an ab initio numerical simulation of solar surface convection. From cross sections through the computational domain of the simulation, we conclude that these `granular lanes' are the visible signature of (horizontally oriented) vortex tubes. The characteristic optical appearance of vortex tubes at the solar surface is explained. We propose that the observed vortex tubes may represent only the large-scale end of a hierarchy of vortex tubes existing near the solar surface.

  14. The tangential velocity profile and momentum transfer within a microgravity, vortex separator 

    E-Print Network [OSTI]

    Ellis, Michael Clay

    2009-05-15

    &M University (TAMU) have developed a microgravity vortex separator (MVS) capable of handling both a wide range of inlet conditions and changes in these conditions. To optimize the MVS design, the effects of nozzle area, separator geometry, and inlet flow rate...

  15. RESEARCH ARTICLE Drag and lift reduction of a 3D bluff-body using active vortex

    E-Print Network [OSTI]

    Wesfreid, José Eduardo

    apparatus (chemical industry, energy production). From the academic point of view, it is an exciting-up with motorized vortex generators is proposed. Thanks to this active device. The optimal configurations depending academic and industrial research. From the indus- trial point of view, flow control is a way to increase

  16. Model of coarsening and vortex formation in vibrated granular rods Igor S. Aranson

    E-Print Network [OSTI]

    Tsimring, Lev S.

    Model of coarsening and vortex formation in vibrated granular rods Igor S. Aranson Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439 Lev S. Tsimring Institute for Nonlinear Science spontaneous formation of the long-range orientational order and large- scale vortices in a system of vibrated

  17. 2094 OPTICS LETTERS / Vol. 28, No. 21 / November 1, 2003 Fundamental and vortex solitons in a

    E-Print Network [OSTI]

    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

  18. "Development of a Free Vortex Wake Method Code for Offshore Floating Wind Turbines"

    E-Print Network [OSTI]

    Mountziaris, T. J.

    "Development of a Free Vortex Wake Method Code for Offshore Floating Wind Turbines" Andrew Sciotti Professor Matthew Lackner Shujian Liu Offshore floating wind turbines (OFWTs) require a unique aerodynamic in refining current mathematical models of offshore wind turbines while also allowing efficient simulations

  19. Sediment resuspension and erosion by vortex rings R. J. Munro,1,a

    E-Print Network [OSTI]

    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

  20. Vortex Ring Interaction with a Particle Layer: Implications for Sediment Transport

    E-Print Network [OSTI]

    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

  1. Microoptomechanical pumps assembled and driven by holographic optical vortex Kosta Ladavac

    E-Print Network [OSTI]

    Grier, David

    Microoptomechanical pumps assembled and driven by holographic optical vortex arrays Kosta Ladavac into dynamically reconfigurable microoptomechanical pumps assembled by optical gradient forces and actuated systems has created a need for new meth­ ods to pump and steer fluids through micrometer­scale channels

  2. Microoptomechanical pumps assembled and driven by holographic optical vortex Kosta Ladavac

    E-Print Network [OSTI]

    Grier, David

    Microoptomechanical pumps assembled and driven by holographic optical vortex arrays Kosta Ladavac into dynamically reconfigurable microoptomechanical pumps assembled by optical gradient forces and actuated systems has created a need for new meth- ods to pump and steer fluids through micrometer-scale channels

  3. Self-consistent anisotropic oscillator with cranked angular and vortex velocities

    E-Print Network [OSTI]

    G. Rosensteel

    1992-11-05

    The Kelvin circulation is the kinematical Hermitian observable that measures the true character of nuclear rotation. For the anisotropic oscillator, mean field solutions with fixed angular momentum and Kelvin circulation are derived in analytic form. The cranking Lagrange multipliers corresponding to the two constraints are the angular and vortex velocities. Self-consistent solutions are reported with a constraint to constant volume.

  4. Vortex-Pair Dynamics in Anisotropic Bistable Media: A Kinematic Approach Aric Hagberg1

    E-Print Network [OSTI]

    Meron, Ehud

    Alamos, New Mexico 87545, USA 2 Department of Solar Energy and Environmental Physics, BIDR, Ben Gurion type upon rotation by =2. We study vortex-pair dynamics by deriving kinematic equations for a front with contour lines that form a closed loop. Equations of this kind, but for isotropic systems and infinite

  5. A Lagrangian approach to identifying vortex pinch-off Clara O'Farrell1

    E-Print Network [OSTI]

    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

  6. Vortex dynamics in three-dimensional continuous myocardium with fiber rotation: Filament instability and fibrillationa...

    E-Print Network [OSTI]

    Mascia, Corrado

    Vortex dynamics in three-dimensional continuous myocardium with fiber rotation: Filament, or filament. This twist can then significantly alter the dynamics of the filament. This paper explores transmural filament and cause a transition to a wave turbulent state characterized by a high density

  7. Under consideration for publication in J. Fluid Mech. 1 Drop impact into a deep pool: vortex

    E-Print Network [OSTI]

    Deegan, Robert

    Under consideration for publication in J. Fluid Mech. 1 Drop impact into a deep pool: vortex of Michigan, Ann Arbor, Michigan 48109, USA 2 Division of Physical Sciences and Engineering & Clean Combustion Arabia 3 Physics of Fluids Group, Faculty of Science and Technology, Mesa+ Institute, University

  8. Instabilities due a vortex at a density interface: gravitational and centrifugal effects

    E-Print Network [OSTI]

    Dixit, Harish

    Instabilities due a vortex at a density interface: gravitational and centrifugal effects Harish N showed recently that the flow is subject to centrifugal Rayleigh-Taylor and spiral Kelvin for example [5]). In the absence of gravity, centrifugal forces are predominant, and we showed recently [4

  9. Aging memory and glassiness of a driven vortex , Guohong Li1

    E-Print Network [OSTI]

    Andrei, Eva Y.

    1 Aging memory and glassiness of a driven vortex system. Xu Du1 , Guohong Li1 , Eva Y. Andrei1 , M memory, aging and nonlinear-dynamics. Glasses[1-11], interfaces[12] and fractures are some examples[13 the deviation from equilibrium. After removing the force, the system ages with time and its subsequent response

  10. Spin waves in circular soft magnetic dots at the crossover between vortex and single domain state

    E-Print Network [OSTI]

    Metlushko, Vitali

    Facility, Cornell University, Ithaca, New York, 14853 USA 6Departamento de Fisica de Materiales We report on linear spin dynamics in the vortex state of Permalloy cylindrical dots subjected In many physical systems such as liquids, plasma, super- conductors, ferromagnets, etc., the topological

  11. Stabilizing a solution of the 2D Navier-Stokes system in the exterior of a bounded domain by means of a control on the boundary

    SciTech Connect (OSTI)

    Gorshkov, Aleksei V [M. V. Lomonosov Moscow State University, Faculty of Mechanics and Mathematics, Moscow (Russian Federation)

    2012-09-30

    The problem of stabilizing a solution of the 2D Navier-Stokes system defined in the exterior of a bounded domain with smooth boundary is investigated. For a given initial velocity field a control on the boundary of the domain must be constructed such that the solution stabilizes to a prescribed vortex solution or trivial solution at the rate of 1/t{sup k}. On the way, related questions are investigated, concerning the behaviour of the spectrum of an operator under a relatively compact perturbation and the existence of attracting invariant manifolds. Bibliography: 21 titles.

  12. PUBLISHED ONLINE: 18 JANUARY 2009 DOI: 10.1038/NPHYS1177 Evidence for an oscillating soliton/vortex ring by

    E-Print Network [OSTI]

    Loss, Daniel

    soliton/vortex ring by density engineering of a Bose­Einstein condensate I. Shomroni, E. Lahoud, S. Levy and J. Steinhauer* When two Bose­Einstein condensates collide with high collisional energy

  13. A scatter diagram approach to the selection of design currents for prediction of marine riser vortex-induced vibration

    E-Print Network [OSTI]

    Donnelly, Jessica Mary

    2004-01-01

    This paper describes a scatter diagram approach for the classification of large numbers of current profiles for use in the prediction of riser fatigue damage due to vortex-induced vibration. Scatter diagrams have long been ...

  14. arXiv:1206.2498v2[cond-mat.other]19Nov2012 Quantum vortex reconnections

    E-Print Network [OSTI]

    Caliari, Marco

    (Dated: 21 November 2012) We study reconnections of quantum vortices by numerically solving the governing . They are the key to understanding quantum turbulence8 , a disordered state of vortex lines which is easily created

  15. Contributions of the wall boundary layer to the formation of the counter-rotating vortex pair in transverse jets

    E-Print Network [OSTI]

    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 ...

  16. Charged Vacuum Bubble Stability

    E-Print Network [OSTI]

    J. R. Morris

    1998-10-20

    A type of scenario is considered where electrically charged vacuum bubbles, formed from degenerate or nearly degenerate vacuua separated by a thin domain wall, are cosmologically produced due to the breaking of a discrete symmetry, with the bubble charge arising from fermions residing within the domain wall. Stability issues associated with wall tension, fermion gas, and Coulombic effects for such configurations are examined. The stability of a bubble depends upon parameters such as the symmetry breaking scale and the fermion coupling. A dominance of either the Fermi gas or the Coulomb contribution may be realized under certain conditions, depending upon parameter values.

  17. Stability of dendritic arrays

    SciTech Connect (OSTI)

    Warren, J.A. ); Langer, J.S. )

    1990-09-15

    We propose an approximate method for studying steady-state properties and linear stability of the dendritic arrays that are formed in directional solidification of alloys. Our analysis is valid at high growth rates where the primary spacing between dendrites is larger than the velocity-dependent solutal diffusion length. We compute a neutral stability boundary and find that, in the situations where we expect our results to be valid, the experimental data of Somboonsuk, Mason, and Trivedi (Metall. Trans. A 15A, 967 (1984)) lie in the stable region, well away from the boundary.

  18. Thermodynamic Stability of Nanobubbles

    E-Print Network [OSTI]

    Phil Attard

    2015-03-15

    The observed stability of nanobubbles contradicts the well-known result in classical nucleation theory, that the critical radius is both microscopic and thermodynamically unstable. Here nanoscopic stability is shown to be the combined result of two non-classical mechanisms. It is shown that the surface tension decreases with increasing supersaturation, and that this gives a nanoscopic critical radius. Whilst neither a free spherical bubble nor a hemispherical bubble mobile on an hydrophobic surface are stable, it is shown that an immobilized hemispherical bubble with a pinned contact rim is stable and that the total entropy is a maximum at the critical radius.

  19. Stabilized PV system

    DOE Patents [OSTI]

    Dinwoodie, Thomas L. (Piedmont, CA)

    2002-12-17

    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.

  20. General rotating quantum vortex filaments in the low-temperature Svistunov model of the local induction approximation

    SciTech Connect (OSTI)

    Van Gorder, Robert A.

    2014-06-15

    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.

  1. Nanostructures for enzyme stabilization

    SciTech Connect (OSTI)

    Kim, Jungbae; Grate, Jay W.; Wang, Ping

    2006-02-02

    The last decade has witnessed notable breakthroughs in nanotechnology with development of various nanostructured materials such as mesoporous materials and nanoparticles. These nanostructures have been used as a host for enzyme immobilization via various approaches, such as enzyme adsorption, covalent attachment, enzyme encapsulation, and sophisticated combinations of methods. This review discusses the stabilization mechanisms behind these diverse approaches; such as confinement, pore size and volume, charge interaction, hydrophobic interaction, and multipoint attachment. In addition, we will introduce recent rigorous approaches to improve the enzyme stability in these nanostructures or develop new nanostructures for the enzyme stabilization. Especially, we will introduce our recent invention of a nanostructure, called single enzyme nanoparticles (SENs). In the form of SENs, each enzyme molecule is surrounded with a nanometer scale network, resulting in stabilization of enzyme activity without any serious limitation for the substrate transfer from solution to the active site. SENs can be further immobilized into mesoporous silica with a large surface area, providing a hierarchical approach for stable, immobilized enzyme systems for various applications, such as bioconversion, bioremediation, and biosensors.

  2. Stabilized chromium oxide film

    DOE Patents [OSTI]

    Garwin, Edward L. (Los Altos, CA); Nyaiesh, Ali R. (Palo Alto, CA)

    1988-01-01

    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.

  3. Stabilized chromium oxide film

    DOE Patents [OSTI]

    Nyaiesh, A.R.; Garwin, E.L.

    1986-08-04

    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.

  4. Large amplitude spin torque vortex oscillations at zero external field using a perpendicular spin polarizer

    SciTech Connect (OSTI)

    Dussaux, A.; Rache Salles, B.; Jenkins, A. S.; Bortolotti, P.; Grollier, J.; Cros, V.; Fert, A.; Khvalkovskiy, A. V.; Kubota, H.; Fukushima, A.; Yakushiji, K.; Yuasa, S.

    2014-07-14

    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.

  5. A new reversal mode in exchange coupled antiferromagnetic/ferromagnetic disks: distorted viscous vortex

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Gilbert, Dustin A.; Ye, Li; Varea, Aïda; Agramunt-Puig, Sebastià; del Valle, Nuria; Navau, Carles; López-Barbera, José Francisco; Buchanan, Kristen S.; Hoffmann, Axel; Sánchez, Alvar; et al

    2015-04-28

    Magnetic vortices have generated intense interest in recent years due to their unique reversal mechanisms, fascinating topological properties, and exciting potential applications. In addition, the exchange coupling of magnetic vortices to antiferromagnets has also been shown to lead to a range of novel phenomena and functionalities. Here we report a new magnetization reversal mode of magnetic vortices in exchange coupled Ir20Mn80/Fe20Ni80 microdots: distorted viscous vortex reversal. In contrast to the previously known or proposed reversal modes, the vortex is distorted close to the interface and viscously dragged due to the uncompensated spins of a thin antiferromagnet, which leads to unexpectedmore »asymmetries in the annihilation and nucleation fields. These results provide a deeper understanding of the physics of exchange coupled vortices and may also have important implications for applications involving exchange coupled nanostructures.« less

  6. Observation of the Larmor and Gouy Rotations with Electron Vortex Beams

    E-Print Network [OSTI]

    Giulio Guzzinati; Peter Schattschneider; Konstantin Bliokh; Franco Nori; Jo Verbeeck

    2013-02-25

    Electron vortex beams carrying intrinsic orbital angular momentum (OAM) are produced in electron microscopes where they are controlled and focused using magnetic lenses. We observe various rotational phenomena arising from the interaction between the OAM and magnetic lenses. First, the Zeeman coupling, proportional to the OAM and magnetic field strength, produces an OAM-independent Larmor rotation of a mode superposition inside the lens. Second, hen passing through the focal plane, the electron beam acquires an additional Gouy phase dependent on the absolute value of the OAM. This brings about the Gouy rotation of the superposition image proportional to the sign of the OAM. A combination of the Larmor and Gouy effects can result in the addition (or subtraction) of rotations, depending on the OAM sign. This behaviour is unique to electron vortex beams and has no optical counterpart, as Larmor rotation occurs only for charged particles. Our experimental results are in agreement with recent theoretical predictions.

  7. Vortex Formation and Evolution in Planet Harboring Disks under Thermal Relaxation

    E-Print Network [OSTI]

    Gomes, A Lobo; Uribe, A L; Pinilla, P; Surville, C

    2015-01-01

    We study the evolution of planet-induced vortices in radially stratified disks, with initial conditions allowing for radial buoyancy. For this purpose we run global two dimensional hydrodynamical simulations, using the PLUTO code. Planet-induced vortices are a product of the Rossby wave instability (RWI) triggered in the edges of a planetary gap. In this work we assess the influence of radial buoyancy for the development of the vortices. We found that radial buoyancy leads to smoother planetary gaps, which generates weaker vortices. This effect is less pronounced for locally isothermal and quasi-isothermal (very small cooling rate) disks. We observed the formation of two generations of vortices. The first generation of vortices is formed in the outer wall of the planetary gap. The merged primary vortex induces accretion, depleting the mass on its orbit. This process creates a surface density enhancement beyond the primary vortex position. The second generation of vortices arise in this surface density enhance...

  8. Quasi-classical approximation in vortex filament dynamics. Integrable systems, gradient catastrophe and flutter

    E-Print Network [OSTI]

    B. G. Konopelchenko; G. Ortenzi

    2012-06-13

    Quasiclassical approximation in the intrinsic description of the vortex filament dynamics is discussed. Within this approximation the governing equations are given by elliptic system of quasi-linear PDEs of the first order. Dispersionless Da Rios system and dispersionless Hirota equation are among them. They describe motion of vortex filament with slow varying curvature and torsion without or with axial flow. Gradient catastrophe for governing equations is studied. It is shown that geometrically this catastrophe manifests as a fast oscillation of a filament curve around the rectifying plane which resembles the flutter of airfoils. Analytically it is the elliptic umbilic singularity in the terminology of the catastrophe theory. It is demonstrated that its double scaling regularization is governed by the Painleve' I equation.

  9. Weakening of the Stratospheric Polar Vortex by Arctic Sea-Ice Loss

    SciTech Connect (OSTI)

    Kim, Baek-Min; Son, Seok-Woo; Min, Seung-Ki; Jeong, Jee-Hoon; Kim, Seong-Joong; Zhang, Xiangdong; Shim, Taehyoun; Yoon, Jin-Ho

    2014-09-02

    Successive cold winters of severely low temperatures in recent years have had critical social and economic impacts on the mid-latitude continents in the Northern Hemisphere. Although these cold winters are thought to be partly driven by dramatic losses of Arctic sea ice, the mechanism that links sea ice loss to cold winters remains a subject of debate. Here, by conducting observational analyses and model experiments, we show how Arctic sea ice loss and cold winters in extra-polar regions are dynamically connected through the polar stratosphere. We find that decreased sea ice cover during early winter months (November-December), especially over the Barents-Kara seas, enhance the upward propagation of planetary-scale waves with wavenumbers of 1 and 2, subsequently weakening the stratospheric polar vortex in mid-winter (January- February). The weakened polar vortex preferentially induces a negative phase of Arctic Oscillation at the surface, resulting in low temperatures in mid-latitudes.

  10. Magnetic vortex crystal formation in the antidot complement of square artificial spin ice

    SciTech Connect (OSTI)

    Araujo, C. I. L. de Silva, R. C.; Ribeiro, I. R. B.; Nascimento, F. S.; Felix, J. F.; Ferreira, S. O.; Moura-Melo, W. A.; Pereira, A. R.; Mól, L. A. S.

    2014-03-03

    We have studied ferromagnetic nickel thin films patterned with square lattices of elongated antidots that are negative analogues of square artificial spin ice. Micromagnetic simulations and direct current magnetic moment measurements reveal in-plane anisotropy of the magnetic hysteresis loops, and the formation of a dense array of magnetic vortices with random polarization and chirality. These multiply-connected antidot arrays could be superior to lattices of disconnected nanodisks for investigations of vortex switching by applied electric current.

  11. Surface-stabilized gold nanocatalysts

    DOE Patents [OSTI]

    Dai, Sheng (Knoxville, TN) [Knoxville, TN; Yan, Wenfu (Oak Ridge, TN) [Oak Ridge, TN

    2009-12-08

    A surface-stabilized gold nanocatalyst includes a solid support having stabilizing surfaces for supporting gold nanoparticles, and a plurality of gold nanoparticles having an average particle size of less than 8 nm disposed on the stabilizing surfaces. The surface-stabilized gold nanocatalyst provides enhanced stability, such as at high temperature under oxygen containing environments. In one embodiment, the solid support is a multi-layer support comprising at least a first layer having a second layer providing the stabilizing surfaces disposed thereon, the first and second layer being chemically distinct.

  12. Comment on “General rotating quantum vortex filaments in the low-temperature Svistunov model of the local induction approximation” [Phys. Fluids 26, 065105 (2014)

    SciTech Connect (OSTI)

    Hietala, Niklas Hänninen, Risto

    2014-11-15

    Van Gorder considers a formulation of the local induction approximation, which allows the vortex to move in the direction of the reference axis [“General rotating quantum vortex filaments in the low-temperature Svistunov model of the local induction approximation,” Phys. Fluids 26, 065105 (2014)]. However, in his analytical and numerical study he does not use it. A mistake in the torsion of a helical vortex is also corrected.

  13. The stability of enrofloxacin 

    E-Print Network [OSTI]

    Dodge, Meagan A

    2013-02-22

    Scholarships Texas ABcM University in partial fulfillment of the requirements for 1997-1998 UNIVERSITY UNDERGRADUATE RESEARCH FELLOWS PROGRAM Approved as to style and content by: Dawn Boothe Department of Veterinary Clinical Pharmacology Susanna Finnell..., Executive Director Honors Programs and Academic Scholarships Fellows Group: Biology ABSTRACT The Stability of Enrofloxacin Meagan Dodge, (Dr. Dawn Boothe) University Undergraduate Fellow, 1997-1998, Texas ARM University, Department of Veterinary...

  14. Chassis stabilization system

    DOE Patents [OSTI]

    Claxton, Gerald L. (Fresno, CA)

    1999-01-01

    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.

  15. Two-step liquid-solid vortex transition with the field along the ab planes in YBa2Cu3O7 crystals

    E-Print Network [OSTI]

    Grigera, Santiago

    , in the mixed state of clean and twinned YBa2Cu3O7 single crystals, support the existence of a vortex and Instituto Balseiro, Comisio´n Nacional de Energi´a Ato´mica, 8400 San Carlos de Bariloche, Argentina-smectic phase when the vortices interact with an attractive periodic potential. The transition from the vortex

  16. A vortex tube is a device of a simple structure with no moving parts that can be used to separate a compressed gas into a hot stream and a cold stream. Many studies have been

    E-Print Network [OSTI]

    A vortex tube is a device of a simple structure with no moving parts that can be used to separate of the energy separation in the vortex tube. Recent rapid development in computational fluid dynamics is providing a powerful tool to investigate the complex flow in the vortex tube. However various issues

  17. Molding the flow of light on the nanoscale: from vortex nanogears to phase-operated plasmonic machinery

    E-Print Network [OSTI]

    Boriskina, Svetlana V; 10.1039/C1NR11406A

    2011-01-01

    Efficient delivery of light into nanoscale volumes by converting free photons into localized charge-density oscillations (surface plasmons) enables technological innovation in various fields from biosensing to photovoltaics and quantum computing. Conventional plasmonic nanostructures are designed as nanoscale analogs of radioantennas and waveguides. Here, we discuss an alternative approach for plasmonic nanocircuit engineering that is based on molding the optical powerflow through 'vortex nanogears' around a landscape of local phase singularities 'pinned' to plasmonic nanostructures. We show that coupling of several vortex nanogears into transmission-like structures results in dramatic optical effects, which can be explained by invoking a hydrodynamic analogy of the 'photon fluid'. The new concept of vortex nanogear transmissions (VNTs) provides new design principles for the development of complex multi-functional phase-operated photonics machinery and, therefore, generates unique opportunities for light gene...

  18. Molding the flow of light on the nanoscale: from vortex nanogears to phase-operated plasmonic machinery

    E-Print Network [OSTI]

    Svetlana V. Boriskina; Bjoern M. Reinhard

    2011-12-07

    Efficient delivery of light into nanoscale volumes by converting free photons into localized charge-density oscillations (surface plasmons) enables technological innovation in various fields from biosensing to photovoltaics and quantum computing. Conventional plasmonic nanostructures are designed as nanoscale analogs of radioantennas and waveguides. Here, we discuss an alternative approach for plasmonic nanocircuit engineering that is based on molding the optical powerflow through 'vortex nanogears' around a landscape of local phase singularities 'pinned' to plasmonic nanostructures. We show that coupling of several vortex nanogears into transmission-like structures results in dramatic optical effects, which can be explained by invoking a hydrodynamic analogy of the 'photon fluid'. The new concept of vortex nanogear transmissions (VNTs) provides new design principles for the development of complex multi-functional phase-operated photonics machinery and, therefore, generates unique opportunities for light generation, harvesting and processing on the nanoscale.

  19. Scattering of electromagnetic waves by vortex density structures associated with interchange instability: Analytical and large scale plasma simulation results

    SciTech Connect (OSTI)

    Sotnikov, V.; Kim, T.; Lundberg, J.; Paraschiv, I.; Mehlhorn, T. A.

    2014-05-15

    The presence of plasma turbulence can strongly influence propagation properties of electromagnetic signals used for surveillance and communication. In particular, we are interested in the generation of low frequency plasma density irregularities in the form of coherent vortex structures. Interchange or flute type density irregularities in magnetized plasma are associated with Rayleigh-Taylor type instability. These types of density irregularities play an important role in refraction and scattering of high frequency electromagnetic signals propagating in the earth ionosphere, in high energy density physics, and in many other applications. We will discuss scattering of high frequency electromagnetic waves on low frequency density irregularities due to the presence of vortex density structures associated with interchange instability. We will also present particle-in-cell simulation results of electromagnetic scattering on vortex type density structures using the large scale plasma code LSP and compare them with analytical results.

  20. Meissner Effect and Vortex Dynamics in Quark Stars -- A Model for Soft Gamma-Ray Repeaters

    E-Print Network [OSTI]

    R. Ouyed; O. Elgaroy; H. Dahle; P. Keranen

    2004-03-24

    We present a new model for soft gamma-ray repeaters based on a quark star born with temperatures above the critical value (T_c) for the onset of the colour-flavor locked superconductivity. The quark star then quickly cools below T_c, expelling a fraction of the surface magnetic field via the Meissner effect. We show that if a small fraction (\\leq 10%) of the surface magnetic field (10^{14} - 10^{15} {\\rm G}) is expelled, it quickly decays via magnetic reconnection and heats up the quark star surface to temperatures > 10^9 {\\rm K}. Created (e^{+},e^{-}) pairs annihilate into gamma rays emitted in a giant burst (the first burst in our model), with a luminosity of \\sim 10^{45} {\\rm ergs} {\\rm s}^{-1}. Subsequent bursts result from the restructuring of the surface magnetic field following the formation and relaxation of a vortex lattice which confines the internal magnetic field. During this phase, energy is sporadically released as a consequence of magnetic reconnection events in the entangled surface magnetic field as it evolves into a smooth, more stable, configuration. The star eventually enters a quiescent phase in which energy is continuously supplied by vortex annihilation at the surface. As the star spins down, the outermost vortex lines will be pushed to the surface where they annihilate and release their confined magnetic field. We show that the corresponding luminosity is L_v \\sim 10^{36} {\\rm ergs} {\\rm s}^{-1} for a typical soft gamma-ray repeater spinning with a period of 8 {\\rm s} and a surface magnetic field not exceeding 10^{15} {\\rm G}. Our model can be applied to any situation where a T>T_{\\rm c} quark star is generated. We discuss the connection between anomalous X-ray pulsars and soft gamma-ray repeaters in the context of our model.

  1. Ultrasound scattering and the study of vortex correlations in disordered flows

    E-Print Network [OSTI]

    Denis Boyer; Fernando Lund

    1999-12-14

    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.

  2. Extraordinary optical transmission and vortex excitation by periodic arrays of Fresnel zone plates

    E-Print Network [OSTI]

    Roszkiewicz, A

    2013-01-01

    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.

  3. 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.

    2011-08-01

    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.

  4. Laser controlled flame stabilization

    DOE Patents [OSTI]

    Early, James W. (Los Alamos, NM); Thomas, Matthew E. (Huntsville, AL)

    2001-01-01

    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.

  5. Venturi/vortex scrubber technology for controlling/recycling chromium electroplating emissions. Final report

    SciTech Connect (OSTI)

    Hay, K.J.; Qi, S.; Holden, B.; Helgeson, N.; Fraser, M.E.

    1999-03-01

    Chromium electroplating is an essential DOD process. Chromium has a combination of qualities that are very difficult to substitute, however, the process itself is inefficient, resulting in the production of byproduct gases that rise and create a mist of chromic acid (strongly regulated as an air pollutant) above the plating tank. Venturi/Vortex Scrubber Technology (VVST) was designed to control chromium electroplating emissions by collecting the gas bubbles before they burst at the solution`s surface. This project demonstrated the Venturi/Vortex Scrubber Technology at the Marine Corps Logistics Base (MCLB) in Albany, GA. This study concluded that the PLRS was able to reduce the flow rate of the current conventional ventilation system at the one tank chromium electroplating facility at MCLB Albany by 63 percent. If new ventilation and control equipment were to be installed at MCLB Albany, this system would offer a 25 percent reduction in capital costs and a 48 percent reduction in annual costs, representing 36 percent in life-cycle cost savings. This study also presented a strong case for the use of Spark-Induced Breakdown Spectroscopy for monitoring real-time chromium emissions above a chromium electroplating tank.

  6. MAP, MAC, and Vortex-rings Configurations in the Weinberg-Salam Model

    E-Print Network [OSTI]

    Rosy Teh; Ban-Loong Ng; Khai-Ming Wong

    2015-03-20

    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 $\\theta_W=\\frac{\\pi}{4}$.

  7. Vortex and structural dynamics of a flexible cylinder in cross-flow

    SciTech Connect (OSTI)

    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)

    2014-05-15

    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.

  8. Direct femtosecond laser ablation of copper with an optical vortex beam

    SciTech Connect (OSTI)

    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)

    2014-09-21

    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 (21000) 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.

  9. A finite element method with mesh adaptivity for computing vortex states in fastrotating BoseEinstein condensates

    E-Print Network [OSTI]

    Recanati, Catherine

    A finite element method with mesh adaptivity for computing vortex states in fast­rotating Bose­Einstein Abstract Numerical computations of stationary states of fast­rotating Bose­Einstein condensates require rotation rates). Key words: Gross--Pitaevskii equation, finite element method, mesh adaptivity, Bose­Einstein

  10. 1242 JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 20, NO. 8, AUGUST 2002 Performances of the Data Vortex Switch Architecture

    E-Print Network [OSTI]

    Bergman, Keren

    the efficient scalability of the architecture under uniform and random traffic conditions while maintaining high1242 JOURNAL OF LIGHTWAVE TECHNOLOGY, VOL. 20, NO. 8, AUGUST 2002 Performances of the Data Vortex Switch Architecture Under Nonuniform and Bursty Traffic Qimin Yang, Member, IEEE, and Keren Bergman

  11. First-Order Transition in the Magnetic Vortex Matter in Superconducting MgB2 Tuned by Disorder

    E-Print Network [OSTI]

    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

  12. Vortex Nucleation in a Stirred Bose-Einstein Condensate Dissipation and turbulence in superfluid flow often involves the creation and

    E-Print Network [OSTI]

    . This observation confirms the role of discrete surface modes in vortex formation. However, when we used a tightly. The nucleation process has been a subject of much theoretical interest [1]. Experiments with Bose. These resonances were close to the frequencies of excitation for surface modes of different multipolarity

  13. Nonequilibrium dynamic phases and plastic flow of driven vortex lattices in superconductors with periodic arrays of pinning sites

    E-Print Network [OSTI]

    Nori, Franco

    of lattices as a driving force is increased. For superconducting systems, experimental work in neutron conductivity. By monitoring the moving vortex lattice, we show that these features coincide with pronounced by elastic theories. Different system parameters produce other phases, including an ordered channel flow

  14. Effect of time-dependent piston velocity program on vortex ring formation in a piston/cylinder arrangement

    E-Print Network [OSTI]

    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

  15. To appear in the ACM SIGGRAPH conference proceedings Filament-based smoke with vortex shedding and variational reconnection

    E-Print Network [OSTI]

    Weissmann, Steffen

    To appear in the ACM SIGGRAPH conference proceedings Filament-based smoke with vortex shedding filaments is highly attractive for the creation of special effects because it gives artists full control filaments over time. Because filaments offer a very compact description of fluid flow, real time

  16. arXiv:nlin.SI/0612065v129Dec2006 FINITE-GAP SOLUTIONS OF THE VORTEX FILAMENT EQUATION

    E-Print Network [OSTI]

    Calini, Annalisa

    arXiv:nlin.SI/0612065v129Dec2006 FINITE-GAP SOLUTIONS OF THE VORTEX FILAMENT EQUATION: ISOPERIODIC filament equation in a neighborhood of multiply covered circles. We construct these solutions by means that matches the deformation data with the knot type of the resulting filament. 1. Introduction In this sequel

  17. Stationary Vortex Loops Induced by Filament Interaction and Local Pinning in a Chemical Reaction-Diffusion System

    E-Print Network [OSTI]

    Steinbock, Oliver

    Stationary Vortex Loops Induced by Filament Interaction and Local Pinning in a Chemical Reaction rings are three-dimensional excitation waves rotating around one-dimensional filament loops but curved filaments. The absence of filament motion can be explained by repulsive interaction

  18. Paper No. 2004-JSC-396 Srivilairit Identification and Analysis of Vortex-Induced Vibrations of a Drilling Riser

    E-Print Network [OSTI]

    Manuel, Lance

    of a deepwater drilling riser. We examine such data from the monitoring of riser accelerations and vortex a deepwater drilling riser. The site has a water depth of 1,000 meters. These riser acceleration data consist of a Drilling Riser using Empirical and Spectral Procedures Tanapat Srivilairit and Lance Manuel Department

  19. Phase stabilities at a glance: Stability diagrams of nickel dipnictides

    SciTech Connect (OSTI)

    Bachhuber, F.; School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland ; Rothballer, J.; Weihrich, R.; Söhnel, T.; Centre for Theoretical Chemistry and Physics, The New Zealand Institute for Advanced Study, Massey University Auckland, Auckland

    2013-12-07

    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.

  20. Ferrocyanide tank waste stability

    SciTech Connect (OSTI)

    Fowler, K.D.

    1993-01-01

    Ferrocyanide wastes were generated at the Hanford Site during the mid to late 1950s as a result of efforts to create more tank space for the storage of high-level nuclear waste. The ferrocyanide process was developed to remove [sup 137]CS from existing waste and newly generated waste that resulted from the recovery of valuable uranium in Hanford Site waste tanks. During the course of research associated with the ferrocyanide process, it was recognized that ferrocyanide materials, when mixed with sodium nitrate and/or sodium nitrite, were capable of violent exothermic reaction. This chemical reactivity became an issue in the 1980s, when safety issues associated with the storage of ferrocyanide wastes in Hanford Site tanks became prominent. These safety issues heightened in the late 1980s and led to the current scrutiny of the safety issues associated with these wastes, as well as current research and waste management programs. Testing to provide information on the nature of possible tank reactions is ongoing. This document supplements the information presented in Summary of Single-Shell Tank Waste Stability, WHC-EP-0347, March 1991 (Borsheim and Kirch 1991), which evaluated several issues. This supplement only considers information particular to ferrocyanide wastes.

  1. Strong vortex core pinning and Barkhausen-free magnetization response in thin Permalloy disks induced by implantation of 1 × 10{sup 4} Ga{sup +} ions

    SciTech Connect (OSTI)

    Fani Sani, F., E-mail: fanisani@ualberta.ca, E-mail: mark.freeman@ualberta.ca; Losby, J. E.; Diao, Z.; Parsons, L. C.; Burgess, J. A. J.; Hiebert, W. K.; Freeman, M. R., E-mail: fanisani@ualberta.ca, E-mail: mark.freeman@ualberta.ca [Department of Physics, University of Alberta, Edmonton, Alberta T6G 2G7 (Canada); National Institute for Nanotechnology (NINT), Edmonton, Alberta T6G 2M9 (Canada); Vick, D. [National Institute for Nanotechnology (NINT), Edmonton, Alberta T6G 2M9 (Canada)

    2014-05-07

    Artificial vortex core pinning sites are induced in thin Permalloy disks by point exposure to as few as 10?000 ions from a focused Ga{sup +} beam. These pinning sites yield a first-order change in the magnetization response of the disk. A single site can keep the vortex core pinned over an applied field range comparable to the vortex annihilation field of the unaltered disk. Several widely separated sites can work together to keep the core pinned in one place, while the Barkhausen effect is eliminated from the magnetization curve over a range approaching the saturation moment of the disk.

  2. Development of venturi/vortex scrubber technology for controlling chromium electroplating hazardous air emissions. Final report

    SciTech Connect (OSTI)

    Hay, K.J.; Qi, S.; Northrup, J.I.; Heck, S.R.

    1998-07-01

    Chromium has a combination of qualities that give chromium electroplating an important role in coating military hardware and armament. However, chromium electroplating and chromium anodizing operations create hazardous air pollutants in the form of hexavalent chromium. Conventional technologies for controlling this pollutant are expensive, noisy, and use a lot of energy and water. Consequently, an air pollution problem is turned into a water pollution problem that also requires treatment. There is a need for an economical control option that pollutes less than conventional technologies. This project developed control technologies to effectively and economically control hazardous air emissions from Army chromium electroplating and anodizing operations, primarily focusing on the development of the Venturi/Vortex Scrubber technology (VVST).

  3. Non-Diffracting Electron Vortex Beams Balancing Their Electron-Electron Interactions

    E-Print Network [OSTI]

    Maor Mutzafi; Ido Kaminer; Gal Harari; Mordechai Segev

    2015-10-10

    By introducing concepts of beam shaping into quantum mechanics, we show how interference effects of the quantum wavefunction describing multiple electrons can exactly balance the repulsion among the electrons. With proper shaping of the fermionic wavefunction, we propose non-diffracting quantum wavepackets of multiple electrons that can also carry orbital angular momentum, in the form of multi-electron non-diffracting vortex beams. The wavefunction is designed to compensate for both the repulsion between electrons and for the diffraction-broadening. This wavefunction shaping facilitates the use of electron beams of higher current in numerous applications, thereby improving the signal-to-noise-ratio in electron microscopy and related systems without compromising on the spatial resolution. Our scheme potentially applies for any beams of charged particles, such as protons, muons and ion beams.

  4. Vortex Zero Modes, Large Flux Limit and Ambjørn-Nielsen-Olesen Magnetic Instabilities

    E-Print Network [OSTI]

    Stefano Bolognesi; Chandrasekhar Chatterjee; Sven Bjarke Gudnason; Kenichi Konishi

    2014-09-23

    In the large flux limit vortices become flux tubes with almost constant magnetic field in the interior region. This occurs in the case of non-Abelian vortices as well, and the study of such configurations allows us to reveal a close relationship between vortex zero modes and the gyromagnetic instabilities of vector bosons in a strong background magnetic field discovered by Nielsen, Olesen and Ambj{\\o}rn. The BPS vortices are exactly at the onset of this instability, and the dimension of their moduli space is precisely reproduced in this way. We present a unifying picture in which, through the study of the linear spectrum of scalars, fermions and W bosons in the magnetic field background, the expected number of translational, orientational, fermionic as well as semilocal zero modes is correctly reproduced in all cases.

  5. Analytic treatment of vortex states in cylindrical superconductors in applied axial magnetic field

    SciTech Connect (OSTI)

    Ludu, A.; Van Deun, J.; Cuyt, A.; Milosevic, M. V.; Peeters, F. M.

    2010-08-15

    We solve the linear Ginzburg-Landau (GL) equation in the presence of a uniform magnetic field with cylindrical symmetry and we find analytic expressions for the eigenfunctions in terms of the confluent hypergeometric functions. The discrete spectrum results from an implicit equation associated to the boundary conditions and it is resolved in analytic form using the continued fractions formalism. We study the dependence of the spectrum and the eigenfunctions on the sample size and the surface conditions for solid and hollow cylindrical superconductors. Finally, the solutions of the nonlinear GL formalism are constructed as expansions in the linear GL eigenfunction basis and selected by minimization of the free energy. We present examples of vortex states and their energies for different samples in enhancing/suppressing superconductivity surroundings.

  6. Optimization of vortex pinning by nanoparticles using simulations of time-dependent Ginzburg-Landau model

    E-Print Network [OSTI]

    A. E. Koshelev; I. A. Sadovskyy; C. L. Phillips; A. Glatz

    2015-10-01

    Introducing nanoparticles into superconducting materials has emerged as an efficient route to enhance their current-carrying capability. We address the problem of optimizing vortex pinning landscape for randomly distributed metallic spherical inclusions using large-scale numerical simulations of time-dependent Ginzburg-Landau equations. We found the size and density of particles for which the highest critical current is realized in a fixed magnetic field. For each particle size and magnetic field, the critical current reaches a maximum value at a certain particle density, which typically corresponds to 15-23% of the total volume being replaced by nonsuperconducting material. For fixed diameter, this optimal particle density increases with the magnetic field. Moreover, we found that the optimal particle diameter slowly decreases with the magnetic field from 4.5 to 2.5 coherence lengths at a given temperature. This result shows that pinning landscapes have to be designed for specific applications taking into account relevant magnetic field scales.

  7. Optimized focal and pupil plane masks for vortex coronagraphs on telescopes with obstructed apertures

    E-Print Network [OSTI]

    Ruane, Garreth J; Huby, Elsa; Mawet, Dimitri; Delacroix, Christian; Carlomagno, Brunella; Piron, Pierre; Swartzlander, Grover A

    2015-01-01

    We present methods for optimizing pupil and focal plane optical elements that improve the performance of vortex coronagraphs on telescopes with obstructed or segmented apertures. Phase-only and complex masks are designed for the entrance pupil, focal plane, and the plane of the Lyot stop. Optimal masks are obtained using both analytical and numerical methods. The latter makes use of an iterative error reduction algorithm to calculate "correcting" optics that mitigate unwanted diffraction from aperture obstructions. We analyze the achieved performance in terms of starlight suppression, contrast, off-axis image quality, and chromatic dependence. Manufacturing considerations and sensitivity to aberrations are also discussed. This work provides a path to joint optimization of multiple coronagraph planes to maximize sensitivity to exoplanets and other faint companions.

  8. 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

    2012-02-01

    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

  9. Ultra-fast magnetic vortex core reversal by a local field pulse

    SciTech Connect (OSTI)

    Rückriem, R.; Albrecht, M., E-mail: manfred.albrecht@physik.uni-augsburg.de [Institute of Physics, Chemnitz University of Technology, 09107 Chemnitz (Germany); Schrefl, T. [St. Pölten University of Applied Science, 3100 St. Pölten (Austria)

    2014-02-03

    Magnetic vortex core reversal of a 20-nm-thick permalloy disk with a diameter of 100?nm was studied by micromagnetic simulations. By applying a global out-of-plane magnetic field pulse, it turned out that the final core polarity is very sensitive to pulse width and amplitude, which makes it hard to control. The reason for this phenomenon is the excitation of radial spin waves, which dominate the reversal process. The excitation of spin waves can be strongly suppressed by applying a local field pulse within a small area at the core center. With this approach, ultra-short reversal times of about 15 ps were achieved, which are ten times faster compared to a global pulse.

  10. Bounds on topological Abelian string-vortex and string-cigar from information-entropic measure

    E-Print Network [OSTI]

    Correa, R A C; Almeida, C A S; da Rocha, Roldao

    2016-01-01

    In this work we obtain bounds on topological Abelian string-vortex in six dimensions using a new measure of configurational complexity known as configurational entropy. In this way, the information-theoretical measure of six dimensional braneworlds scenarios are capable to probe situations where the parameters responsible for the thickness are arbitrary. The so-called Configurational Entropy (CE) selects the best value of the parameter in the model. This is accomplished by minimizing the CE, namely, by selecting the most appropriate parameters in the model that correspond to the most organized system, based upon Shannon information theory. This information-theoretical measure of complexity provides a complementary perspective to situations where strictly energy-based arguments are inconclusive. We show that the higher the energy the higher the configurational entropy, what shows an important correlation between the energy of the a localized field configuration and its associated entropic measure.

  11. Analytical description of high-aperture STED resolution with 0-2$\\pi$ vortex phase modulation

    E-Print Network [OSTI]

    Xie, Hao; Jin, Dayong; Xi, Peng

    2013-01-01

    Stimulated emission depletion (STED) can achieve optical super-resolution, with the optical diffraction limit broken by the suppression on the periphery of the fluorescent focal spot. Previously, it is generally experimentally accepted that there exists an inverse square root relationship with the STED power and the resolution, yet without strict analytical description. In this paper, we have analytically verified the relationship between the STED power and the achievable resolution from vector optical theory for the widely used 0-2$\\pi$ vortex phase modulation. Electromagnetic fields of the focal region of a high numerical aperture objective are calculated and approximated into polynomials, and analytical expression of resolution as a function of the STED intensity has been derived. As a result, the resolution can be estimated directly from the measurement of the saturation power of the dye and the STED power applied.

  12. Method for the detection of a magnetic field utilizing a magnetic vortex

    DOE Patents [OSTI]

    Novosad, Valentyn (Chicago, IL); Buchanan, Kristen (Batavia, IL)

    2010-04-13

    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.

  13. Necessary conditions for stabilization agreements

    E-Print Network [OSTI]

    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 ...

  14. Stabilization and Global Climate Policy

    E-Print Network [OSTI]

    Sarofim, Marcus C.

    Academic and political debates over long-run climate policy often invoke “stabilization” of atmospheric concentrations of greenhouse gases (GHGs), but only rarely are non-CO2 greenhouse gases addressed explicitly. Even ...

  15. Quantum stabilizer codes and beyond 

    E-Print Network [OSTI]

    Sarvepalli, Pradeep Kiran

    2008-10-10

    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... Committee Members, Donald K. Friesen Jennifer L. Welch Scott L. Miller Head of Department, Valerie E. Taylor August 2008 Major Subject: Computer Science iii ABSTRACT Quantum Stabilizer Codes and Beyond. (August 2008) Pradeep Kiran Sarvepalli, B.Tech., Indian...

  16. Interaction of a Shock with a Longitudinal Vortex 1 Gordon Erlebacher 2 , M.Y. Hussaini 3 and ChiWang Shu 4

    E-Print Network [OSTI]

    Erlebacher, Gordon

    vortex shed from a canard of a supersonic fighter plane intersects the shock that lies over the wing are appropriate), resulting in destabilizing forces on the airplane (D'elery et al: 1984). Thus, a theoretical

  17. U31: Vehicle Stability and Dynamics: Electronic Stability Control

    SciTech Connect (OSTI)

    Petrolino, Joseph; Spezia, Tony; Arant, Michael; Delorenzis, Damon; LaClair, Tim J; Lim, Alvin; Pape, Doug

    2011-01-01

    A team led by NTRCI is working to improve the roll and yaw stability of heavy duty combination trucks through developing stability algorithms, assembling demonstration hardware, and investigating robust wireless communication. Modern electronic stability control (ESC) products automatically slow a vehicle rounding a corner too quickly or apply individual brakes when necessary to improve the steering characteristics of a vehicle. Air brake systems in North America provide no electronic communication between a tractor and semitrailer, limiting the degree to which control systems can be optimized. Prior research has demonstrated stability improvements where dynamic measurements and control commands are communicated between units of a vehicle. Three related activities were undertaken: (1) Develop an algorithm for the optimum yaw and roll control of a combination vehicle. Vehicle state parameters needed to control the vehicle and the proper brake response were determined. An integrated stability control for the tractor and semitrailer requires communication between the two units. Dynamic models were used to assess the algorithm. (2) Implement the ESC algorithm in the laboratory. Hardware components suitable for the harsh environment for measurement, sensor-to-controller communication, and semitrailer-to-tractor communication and brake actuation were specified and assembled as a working system. The goal was to collect the needed vehicle state information, transmit the information to the ESC system, and then actuate the brakes in response to controller commands. (3) Develop a wireless network with the data rate and reliability necessary to communicate dynamic signals for a vehicle stability control system. Adaptive connectivity-aware, multi-hop routing was selected because it can perform in the harsh environment where packet collisions and fading often will exist. The protocol is to give high priority to urgent messages.

  18. Material Stabilization Project Management Plan

    SciTech Connect (OSTI)

    SPEER, D.R.

    1999-09-01

    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.

  19. Vortex Diode Analysis and Testing for Fluoride Salt-Cooled High-Temperature Reactors

    SciTech Connect (OSTI)

    Yoder Jr, Graydon L [ORNL; Elkassabgi, Yousri M. [Texas A& M University, Kingsville; De Leon, Gerardo I. [Texas A& M University, Kingsville; Fetterly, Caitlin N. [Texas A& M University, Kingsville; Ramos, Jorge A. [Texas A& M University, Kingsville; Cunningham, Richard Burns [University of Tennessee, Knoxville (UTK)

    2012-02-01

    Fluidic diodes are presently being considered for use in several fluoride salt-cooled high-temperature reactor designs. A fluidic diode is a passive device that acts as a leaky check valve. These devices are installed in emergency heat removal systems that are designed to passively remove reactor decay heat using natural circulation. The direct reactor auxiliary cooling system (DRACS) uses DRACS salt-to-salt heat exchangers (DHXs) that operate in a path parallel to the core flow. Because of this geometry, under normal operating conditions some flow bypasses the core and flows through the DHX. A flow diode, operating in reverse direction, is-used to minimize this flow when the primary coolant pumps are in operation, while allowing forward flow through the DHX under natural circulation conditions. The DRACSs reject the core decay heat to the environment under loss-of-flow accident conditions and as such are a reactor safety feature. Fluidic diodes have not previously been used in an operating reactor system, and therefore their characteristics must be quantified to ensure successful operation. This report parametrically examines multiple design parameters of a vortex-type fluidic diode to determine the size of diode needed to reject a particular amount of decay heat. Additional calculations were performed to size a scaled diode that could be tested in the Oak Ridge National Laboratory Liquid Salt Flow Loop. These parametric studies have shown that a 152.4 mm diode could be used as a test article in that facility. A design for this diode is developed, and changes to the loop that will be necessary to test the diode are discussed. Initial testing of a scaled flow diode has been carried out in a water loop. The 150 mm diode design discussed above was modified to improve performance, and the final design tested was a 171.45 mm diameter vortex diode. The results of this testing indicate that diodicities of about 20 can be obtained for diodes of this size. Experimental results show similar trends as the computational fluid dynamics (CFD) results presented in this report; however, some differences exist that will need to be assessed in future studies. The results of this testing will be used to improve the diode design to be tested in the liquid salt loop system.

  20. Stability of charged thin shells

    SciTech Connect (OSTI)

    Eiroa, Ernesto F.; Simeone, Claudio

    2011-05-15

    In this article we study the mechanical stability of spherically symmetric thin shells with charge, in Einstein-Maxwell and Einstein-Born-Infeld theories. We analyze linearized perturbations preserving the symmetry, for shells around vacuum and shells surrounding noncharged black holes.

  1. STABILITY OF WASTE CONTAINMENT FACILITIES

    E-Print Network [OSTI]

    placement or regrading, (v) typical landfilling, and (vi) final closure. After identifying the potential containment facilities. These failures include landfill liner and cover systems and involve both natural recirculation, lateral and vertical expansions, and interim or temporary slopes on the stability of landfills

  2. 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:...

  3. Stability of Molten Core Materials

    SciTech Connect (OSTI)

    Layne Pincock; Wendell Hintze

    2013-01-01

    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.

  4. Material stabilization characterization management plan

    SciTech Connect (OSTI)

    GIBSON, M.W.

    1999-08-31

    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.

  5. Basis Document for Sludge Stabilization

    SciTech Connect (OSTI)

    WILKINS, N.E.

    2000-04-03

    Vault personnel have begun a program of radiographing plutonium metal cans. Metal that appears to be corroded will be processed through the furnaces in Glovebox HC-21C. The fire suppression system activation temperature will be deleted because it is not maintained by PFP Stabilization.

  6. Topological relics of symmetry breaking: Winding numbers and scaling tilts from random vortex-antivortex pairs

    E-Print Network [OSTI]

    Wojciech H. Zurek

    2014-10-01

    I show that random distributions of vortex-antivortex pairs (rather than of individual vortices) lead to scaling of typical winding numbers W trapped inside a loop of circumference C with the square root of C when the expected winding numbers are large. Such scaling is consistent with the Kibble-Zurek mechanism (KZM). By contrast, distribution of individual vortices with randomly assigned topological charges would result in the dispersion of W scaling with the square root of the area inside C. Scaling of the dispersion of W and of the probability of detection of non-zero W with C can be also studied for loops so small that non-zero windings are rare. In this case I show a doubling of the scaling of dispersion with C when compared to the scaling of dispersion in the large W regime. Moreover, probability of trapping of a non-zero W becomes, in this case, proportional to the area subtended by C (hence, to the square of circumference). This quadruples, as compared with large winding numbers regime, the exponent in the power law dependence of the frequency of trapping of W=+1 or W=-1 on C. Such change of the power law exponent by a FACTOR OF FOUR implies quadrupling of the scaling of the frequency of winding number trapping with the quench rate, and is of key importance for experimental tests of KZM.

  7. Temporal evolution characteristics of an annular-mode gliding arc discharge in a vortex flow

    SciTech Connect (OSTI)

    Zhao, Tian-Liang; Liu, Jing-Lin; Li, Xiao-Song; Liu, Jin-Bao; Song, Yuan-Hong; Xu, Yong; Zhu, Ai-Min

    2014-05-15

    An annular-mode gliding arc discharge powered by a 50?Hz alternating current (ac) supply was studied in a vortex flow of dry and humid air. Its temporal evolution characteristics were investigated by electrical measurement, temporally resolved imaging, and temporally resolved optical emission spectroscopic measurements. Three discharge stages of arc-ignition, arc-gliding, and arc-extinction were clearly observed in each half-cycle of the discharge. During the arc-gliding stage, the intensity of light emission from the arc root at the cathode was remarkably higher than that at other areas. The spectral intensity of N{sub 2}(C{sup 3}?{sub u}?B{sup 3}?{sub g}) during the arc-ignition stage was much higher than that during the arc-gliding stage, which was contrary to the temporal evolutions of spectral intensities for N{sub 2}{sup +}(B{sup 2}?{sub u}{sup +}?X{sup 2}?{sub g}{sup +}) and OH(A{sup 2}?{sup +}?X{sup 2}?{sub i}). Temporally resolved vibrational and rotational temperatures of N{sub 2} were also presented and decreased with increasing the water vapor content.

  8. Hingeless flow control over delta wing planforms 

    E-Print Network [OSTI]

    Moeller, Edward Brian

    1999-01-01

    was evaluated as a possible replacement to conventional moving or hinged control surfaces. Testing was conducted with a 60-degree delta wing model incorporating Pneumatic Vortex Control (PVC) actuators. These actuators delivered high pressure jets of varying...

  9. Plasma stability in a dipole magnetic field

    E-Print Network [OSTI]

    Simakov, Andrei N., 1974-

    2001-01-01

    The MHD and kinetic stability of an axially symmetric plasma, confined by a poloidal magnetic field with closed lines, is considered. In such a system the stabilizing effects of plasma compression and magnetic field ...

  10. Characterization of Instrumental Phase Stability

    E-Print Network [OSTI]

    D. Y. Kubo; T. R. Hunter; R. D. Christensen; P. I. Yamaguchi

    2007-04-17

    Atmospheric water vapor causes significant undesired phase fluctuations for the Submillimeter Array (SMA) interferometer, particularly in its highest frequency observing band of 690 GHz. One proposed solution to this atmospheric effect is to observe simultaneously at two separate frequency bands of 230 and 690 GHz. Although the phase fluctuations have a smaller magnitude at the lower frequency, they can be measured more accurately and on shorter timescales due to the greater sensitivity of the array to celestial point source calibrators at this frequency. In theory, we can measure the atmospheric phase fluctuations in the 230 GHz band, scale them appropriately with frequency, and apply them to the data in 690 band during the post-observation calibration process. The ultimate limit to this atmospheric phase calibration scheme will be set by the instrumental phase stability of the IF and LO systems. We describe the methodology and initial results of the phase stability characterization of the IF and LO systems.

  11. Geometric conditions for robust stability 

    E-Print Network [OSTI]

    Chapellat, Herve?

    1987-01-01

    ) Michael T. Lo gnecker (Member) Jo W. Howze (Head of Department) December 1987 ABSTRACT Ceometric Conditions for Robust Stability (Decenrber 1987) Herve Chapellat, B. S. , E. N. S. T. (Paris) Chair of Advisory Committee: Dr. S. P. Bhsttacharyya.... Georghiades and M. T. Longnecker for their comments and for taking time in reviewing this thesis. Finally, I wish to express deep gratitude to my former school in Paris, the Ecole ?ationale Supericure des Telecornrnurdcations (E. lV. S. T. ), that allosved...

  12. Radial stability in stratified stars

    E-Print Network [OSTI]

    Pereira, Jonas P

    2015-01-01

    We formulate within a generalized distributional approach the treatment of the stability against radial perturbations for both neutral and charged stratified stars in Newtonian and Einstein's gravity. We obtain from this approach the boundary conditions connecting two any phases within a star and underline its relevance for realistic models of compact stars with phase transitions, owing to the modification of the star's set of eigenmodes with respect to the continuous case.

  13. Radial stability in stratified stars

    E-Print Network [OSTI]

    Jonas P. Pereira; Jorge A. Rueda

    2015-01-12

    We formulate within a generalized distributional approach the treatment of the stability against radial perturbations for both neutral and charged stratified stars in Newtonian and Einstein's gravity. We obtain from this approach the boundary conditions connecting two any phases within a star and underline its relevance for realistic models of compact stars with phase transitions, owing to the modification of the star's set of eigenmodes with respect to the continuous case.

  14. A Stability of LCLS Linac Modulators

    SciTech Connect (OSTI)

    Decker, F.-J.; Krasnykh, A.; Morris, B.; Nguyen, M.; /SLAC

    2012-06-13

    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.

  15. Stabilization

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power AdministrationRobust,Field-effect Photovoltaics -7541C.3 SpecialSponsor GuidelinesPlasma Physics and Error

  16. Investigation of vortex generators for augmentation of wind turbine power performance

    SciTech Connect (OSTI)

    Griffin, D.A. [Lynette (R.) and Associates, Seattle, WA (United States)

    1996-12-01

    This study focuses on the use of vortex generators (VGs) for performance augmentation of the stall-regulated AWT-26 wind turbine. The goal was to design a VG array which would increase annual energy production (AEP) by increasing power output at moderate wind speeds, without adversely affecting the loads or stall-regulation performance of the turbine. Wind tunnel experiments were conducted at the University of Washington to evaluate the effect of VGs on the AWT-26 blade, which is lofted from National Renewable Energy Laboratory (NREL) S-series airfoils. Based on wind-tunnel results and analysis, a VG array was designed and then tested on the AWT-26 prototype, designated P1. Performance and loads data were measured for P1, both with and without VGs installed. the turbine performance with VGs met most of the design requirements; power output was increased at moderate wind speeds with a negligible effect on peak power. However, VG drag penalties caused a loss in power output for low wind speeds, such that performance with VGs resulted in a net decrease in AEP for sites having annual average wind speeds up to 8.5 m/s. While the present work did not lead to improved AEP for the AWT-2 turbine, it does provide insight into performance augmentation of wind turbines with VGs. The safe design of a VG array for a stall-regulated turbine has been demonstrated, and several issues involving optimal performance with VGs have been identified and addressed. 15 refs., 34 figs., 10 tabs.

  17. L1 Stability for scalar balance laws. L1 Stability for scalar balance laws.

    E-Print Network [OSTI]

    Mercier, Magali

    L1 Stability for scalar balance laws. L1 Stability for scalar balance laws. Control 2010 Magali Mercier (Institut Camille Jordan, Lyon) L1 Stability for scalar balance laws. Parma, 15th February 2010 1 / 30 #12;L1 Stability for scalar balance laws. Introduction. Introduction Scalar balance

  18. Comment on “Motion of a helical vortex filament in superfluid {sup 4}He under the extrinsic form of the local induction approximation” [Phys. Fluids 25, 085101 (2013)

    SciTech Connect (OSTI)

    Hietala, Niklas Hänninen, Risto

    2014-01-15

    We comment on the paper by Van Gorder [“Motion of a helical vortex filament in superfluid {sup 4}He under the extrinsic form of the local induction approximation,” Phys. Fluids 25, 085101 (2013)]. We point out that the flow of the normal fluid component parallel to the vortex will often lead into the Donnelly–Glaberson instability, which will cause the amplification of the Kelvin wave. We explain why the comparison to local nonlinear equation is unreasonable, and remark that neglecting the motion in the x-direction is not reasonable for a Kelvin wave with an arbitrary wavelength and amplitude. The correct equations in the general case are also derived.

  19. Code constructions and code families for nonbinary quantum stabilizer code 

    E-Print Network [OSTI]

    Ketkar, Avanti Ulhas

    2005-11-01

    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...

  20. High-Compression-Ratio; Atkinson-Cycle Engine Using Low-Pressure Direct Injection and Pneumatic-Electronic Valve Actuation Enabled by Ionization Current and Foward-Backward Mass Air Flow Sensor Feedback

    SciTech Connect (OSTI)

    Harold Schock; Farhad Jaberi; Ahmed Naguib; Guoming Zhu; David Hung

    2007-12-31

    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.

  1. Tritium systems test assembly stabilization

    SciTech Connect (OSTI)

    Jasen, W. G. (William G.); Michelotti, R. A. (Roy A.); Anast, K. R. (Kurt R.); Tesch, Charles

    2004-01-01

    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.

  2. From the Newton's laws to motions of the fluid and superfluid vacuum: vortex tubes, rings, and others

    E-Print Network [OSTI]

    Sbitnev, Valeriy I

    2014-01-01

    Owing to three conditions (namely: (a) the velocity is represented by sum of irrotational and solenoidal components; (b) the fluid is barotropic; (c) a bath with the fluid undergoes vertical vibrations) the Navier-Stokes equation admits reduction to the modified Hamilton-Jacobi equation. The modification term is the Bohmian(quantum) potential. This reduction opens possibility to define a complex-valued function, named the wave function, which is a solution of the Schr\\"{o}dinger equation. The solenoidal component being added to the momentum operator poses itself as a vector potential by analogy with the magnetic vector potential. The vector potential is represented by the solenoidal velocity multiplied by mass of the fluid element. Vortex tubes, rings, and balls along with the wave function guiding these objects are solutions of this equation. Motion of the vortex balls along the Bohmian trajectories gives a model of droplets moving on the fluid surface. A peculiar fluid is the superfluid physical vacuum. It ...

  3. Vacuum Stability of Standard Model^{++}

    E-Print Network [OSTI]

    Anchordoqui, Luis A; Goldberg, Haim; Huang, Xing; Lust, Dieter; Taylor, Tomasz R; Vlcek, Brian

    2013-01-01

    The latest results of the ATLAS and CMS experiments point to a preferred narrow Higgs mass range (m_h \\simeq 124 - 126 GeV) in which the effective potential of the Standard Model (SM) develops a vacuum instability at a scale 10^{9} -10^{11} GeV, with the precise scale depending on the precise value of the top quark mass and the strong coupling constant. Motivated by this experimental situation, we present here a detailed investigation about the stability of the SM^{++} vacuum, which is characterized by a simple extension of the SM obtained by adding to the scalar sector a complex SU(2) singlet that has the quantum numbers of the right-handed neutrino, H", and to the gauge sector an U(1) that is broken by the vacuum expectation value of H". We derive the complete set of renormalization group equations at one loop. We then pursue a numerical study of the system to determine the triviality and vacuum stability bounds, using a scan of 10^4 random set of points to fix the initial conditions. We show that, if there...

  4. Highly efficient electron vortex beams generated by nanofabricated phase holograms Vincenzo Grillo, Gian Carlo Gazzadi, Ebrahim Karimi, Erfan Mafakheri, Robert W. Boyd, and Stefano Frabboni

    E-Print Network [OSTI]

    Boyd, Robert W.

    Highly efficient electron vortex beams generated by nanofabricated phase holograms Vincenzo Grillo membranes using electron-beam lithography J. Vac. Sci. Technol. B 31, 06F402 (2013); 10.1063/1.4810917 Ion and electron beam nanofabrication of the which-way double-slit experiment in a transmission

  5. Coreless vortex formation in a spinor Bose-Einstein condensate Topological defects vary between superfluid systems described by scalar and vector

    E-Print Network [OSTI]

    Coreless vortex formation in a spinor Bose-Einstein condensate Topological defects vary between-polarized condensates, line defects such as vortices have cores where the density of condensed particles is necessarily zero to keep the order parameter single-valued. However, in condensates with an internal, spin degree

  6. Topological vortex formation in a Bose-Einstein condensate Following the theoretical suggestion [1], we have demonstrated a new method to

    E-Print Network [OSTI]

    Topological vortex formation in a Bose-Einstein condensate Following the theoretical suggestion [1], we have demonstrated a new method to create vortices in Bose-Einstein condensates. Vortices were imprinted into the condensate wavefunction using topological phases. Sodium condensates held in an Ioffe

  7. Response to “Comment on ‘General rotating quantum vortex filaments in the low-temperature Svistunov model of the local induction approximation’” [Phys. Fluids 26, 119101 (2014)

    SciTech Connect (OSTI)

    Van Gorder, Robert A.

    2014-11-15

    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.

  8. Optimization Online - Quantitative Stability Analysis of Stochastic ...

    E-Print Network [OSTI]

    Jie Zhang

    2015-06-03

    Jun 3, 2015 ... Quantitative Stability Analysis of Stochastic Quasi-Variational Inequality Problems and Applications. Jie Zhang(zhangjie04212001 ***at*** ...

  9. Nonlinear stability of ideal fluid equilibria

    SciTech Connect (OSTI)

    Holm, D.D.

    1988-01-01

    The Lyapunov method for establishing stability is related to well- known energy principles for nondissipative dynamical systems. A development of the Lyapunov method for Hamiltonian systems due to Arnold establishes sufficient conditions for Lyapunov stability by using the energy plus other conserved quantities, together with second variations and convexity estimates. When treating the stability of ideal fluid dynamics within the Hamiltonian framework, a useful class of these conserved quantities consists of the Casimir functionals, which Poisson-commute with all functionals of the dynamical fluid variables. Such conserved quantities, when added to the energy, help to provide convexity estimates that bound the growth of perturbations. These convexity estimates, in turn, provide norms necessary for establishing Lyapunov stability under the nonlinear evolution. In contrast, the commonly used second variation or spectral stability arguments only prove linearized stability. As ideal fluid examples, in these lectures we discuss planar barotropic compressible fluid dynamics, the three-dimensional hydrostatic Boussinesq model, and a new set of shallow water equations with nonlinear dispersion due to Basdenkov, Morosov, and Pogutse(1985). Remarkably, all three of these samples have the same Hamiltonian structure and, thus, possess the same Casimir functionals upon which their stability analyses are based. We also treat stability of modified quasigeostrophic flow, a problem whose Hamiltonian structure and Casimirs closely resemble Arnold's original example. Finally, we discuss some aspects of conditional stability and the applicability of Arnold's development of the Lyapunov technique. 100 refs.

  10. Nonlinear symmetric stability of planetary atmospheres

    SciTech Connect (OSTI)

    Bowman, J.C.; Shepherd, T.G.

    1994-11-01

    The energy-Casimir method is applied to the problem of symmetric stability in the context of a compressible, hydrostatic planetary atmosphere with a general equation of state. Linear stability criteria for symmetric disturbances to a zonally symmetric baroclinic flow are obtained. In the special case of a perfect gas the results of Stevens (1983) are recovered. Nonlinear stability conditions are also obtained that, in addition to implying linear stability, provide an upper bound on a certain positive-definite measure of disturbance amplitude.

  11. Stabilization of polyaniline solutions through additives

    DOE Patents [OSTI]

    Wrobleski, Debra A. (Los Alamos, NM); Benicewicz, Brian C. (Los Alamos, NM)

    1996-01-01

    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.

  12. Stabilization of polyaniline solutions through additives

    DOE Patents [OSTI]

    Wrobleski, D.A.; Benicewicz, B.C.

    1996-12-10

    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.

  13. Quench propagation velocity for highly stabilized conductors

    SciTech Connect (OSTI)

    Mints, R.G. |; Ogitsu, T. |; Devred, A.

    1995-05-01

    Quench propagation velocity in conductors having a large amount of stabilizer outside the multifilamentary area is considered. It is shown that the current redistribution process between the multifilamentary area and the stabilizer can strongly effect the quench propagation. A criterion is derived determining the conditions under which the current redistribution process becomes significant, and a model of effective stabilizer area is suggested to describe its influence on the quench propagation velocity. As an illustration, the model is applied to calculate the adiabatic quench propagation velocity for a conductor geometry with a multifilamentary area embedded inside the stabilizer.

  14. Adaptive Stabilization of Nonlinear Stochastic Systems

    SciTech Connect (OSTI)

    Florchinger, P. [URA CNRS No. 399, Departement de Mathematiques, UFR MIM, Universite de Metz, Ile du Saulcy, F 57045 Metz Cedex (France)

    1998-07-15

    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.

  15. Rocky Flats ash test procedure (sludge stabilization)

    SciTech Connect (OSTI)

    Winstead, M.L.

    1995-09-14

    Rocky Flats Ash items have been identified as the next set of materials to be stabilized. This test is being run to determine charge sizes and soak times to completely stabilize the Rocky Flats Ash items. The information gathered will be used to generate the heating rampup cycle for stabilization. This test will also gain information on the effects of the glovebox atmosphere (moisture) on the stabilized material. This document provides instructions for testing Rocky Flats Ash in the HC-21C muffle furnace process.

  16. Chemically stabilized ionomers containing inorganic fillers

    DOE Patents [OSTI]

    Roelofs, Mark Gerrit

    2013-12-31

    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.

  17. The limits of filopodium stability

    E-Print Network [OSTI]

    Sander Pronk; Phillip L. Geissler; Daniel A. Fletcher

    2008-03-03

    Filopodia are long, finger-like membrane tubes supported by cytoskeletal filaments. Their shape is determined by the stiffness of the actin filament bundles found inside them and by the interplay between the surface tension and bending rigidity of the membrane. Although one might expect the Euler buckling instability to limit the length of filopodia, we show through simple energetic considerations that this is in general not the case. By further analyzing the statics of filaments inside membrane tubes, and through computer simulations that capture membrane and filament fluctuations, we show under which conditions filopodia of arbitrary lengths are stable. We discuss several in vitro experiments where this kind of stability has already been observed. Furthermore, we predict that the filaments in long, stable filopodia adopt a helical shape.

  18. Surface rheology and interface stability.

    SciTech Connect (OSTI)

    Yaklin, Melissa A.; Cote, Raymond O.; Moffat, Harry K.; Grillet, Anne Mary; Walker, Lynn; Koehler, Timothy P.; Reichert, Matthew D.; Castaneda, Jaime N.; Mondy, Lisa Ann; Brooks, Carlton, F.

    2010-11-01

    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.

  19. UNDERSTANDING FORCES THAT CONTRIBUTE TO PROTEIN STABILITY: APPLICATION FOR INCREASING PROTEIN STABILITY 

    E-Print Network [OSTI]

    Fu, Hailong

    2010-07-14

    The aim of this study is to further our understanding of the forces that contribute to protein stability and to investigate how site-directed mutagenesis might be used for increasing protein stability. Eleven proteins ...

  20. Analyzing the Stability ofAnalyzing the Stability of --Carotene and PVCarotene and PV--1919

    E-Print Network [OSTI]

    Petta, Jason

    Analyzing the Stability ofAnalyzing the Stability of --Carotene and PVCarotene and PV--1919 nanoparticles #12;Goals of Second ProjectGoals of Second Project Study of PVStudy of PV--1919 --Determine

  1. Modification of vortex dynamics and transport properties of transitional axisymmetric jets using zero-net-mass-flux actuation

    SciTech Connect (OSTI)

    Önder, Asim; Meyers, Johan

    2014-07-15

    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.

  2. Seoul, South Korea -classification deteriorating slope stability -Robert Hack 1 SLOPE STABILITY CLASSIFICATION

    E-Print Network [OSTI]

    Hack, Robert

    Seoul, South Korea - classification deteriorating slope stability - Robert Hack 1 SLOPE STABILITY CLASSIFICATION OF TIME DEPENDENT DETERIORATING SLOPES Seoul, Korea, 29 February 2008 Robert Hack Engineering) The Netherlands #12;Seoul, South Korea - classification deteriorating slope stability - Robert Hack 2 Jan van

  3. Aalborg Universitet Modeling, Stability Analysis and Active Stabilization of Multiple DC-Microgrids Clusters

    E-Print Network [OSTI]

    Vasquez, Juan Carlos

    Aalborg Universitet Modeling, Stability Analysis and Active Stabilization of Multiple DC-Microgrids and Active Stabilization of Multiple DC-Microgrids Clusters. In Proceedings of the 2014 IEEE International of Multiple DC-Microgrid Clusters," in Proc. IEEE International Energy Conference (EnergyCon'14), 2014

  4. Stability and scalability of piezoelectric flags

    E-Print Network [OSTI]

    Wang, Xiaolin; Li, Chenyang; Young, Yin Lu

    2015-01-01

    We investigate the effect of piezoelectric (PZT) material on the flutter speed, vibration mode and frequency, and energy harvesting power and efficiency of a flexible flag in various fluids. We develop a fully coupled fluid-solid-electric model by combining the inviscid vortex sheet model with a linear electro-mechanical coupling model. A resistance only circuit and a resonant resistance-inductance (RL) circuit are considered. For a purely resistive circuit, an increased electro-mechanical coupling factor results in an increased flutter speed, vibration frequency, averaged electric power and efficiency. A consistent optimal resistance is found that maximizes the flutter speed and the energy harvesting power. For a resonant RL circuit, by tuning the inductance to match the circuit frequency to the flag's vibration frequency, the flutter speed can be greatly decreased, and a larger averaged power and efficiency are obtained. We also consider a model scale set-up with several commonly used commercial materials f...

  5. Nanoparticle halos: A new colloid stabilization mechanism

    E-Print Network [OSTI]

    Braun, Paul

    Nanoparticle halos: A new colloid stabilization mechanism Valeria Tohver*, James E. Smay*, Alan, 2001 (received for review February 7, 2001) A new mechanism for regulating the stability of colloidal for tailoring the behavior of com- plex fluids. Colloidal suspensions enjoy widespread use in applications

  6. On the Jacobi-Metric Stability Criterion

    E-Print Network [OSTI]

    M. A. Gonzalez Leon; J. L. Hernandez Pastora

    2007-05-30

    We investigate the exact relation existing between the stability equation for the solutions of a mechanical system and the geodesic deviation equation of the associated geodesic problem in the Jacobi metric constructed via the Maupertuis-Jacobi Principle. We conclude that the dynamical and geometrical approaches to the stability/instability problem are not equivalent.

  7. A New Stabilized Nodal Integration Approach

    SciTech Connect (OSTI)

    Puso, M; Zywicz, E; Chen, J S

    2006-02-08

    A new stabilized nodal integration scheme is proposed and implemented. In this work, focus is on the natural neighbor meshless interpolation schemes. The approach is a modification of the stabilized conforming nodal integration (SCNI) scheme and is shown to perform well in several benchmark problems.

  8. The influence of current collectors on Tayler instability and electro-vortex flows in liquid metal batteries

    E-Print Network [OSTI]

    Weber, N; Priede, J; Stefani, F; Weier, T

    2014-01-01

    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.

  9. Negative specific heat for quasi-2D vortex structures in electron plasmas: an explicit, closed-form derivation

    E-Print Network [OSTI]

    T. D. Andersen; C. C. Lim

    2008-02-29

    Negative specific heat is a dramatic phenomenon where processes decrease in temperature when adding energy. It has been observed in gravo-thermal collapse of globular clusters. We now report finding this phenomenon in bundles of nearly parallel, periodic, single-sign generalized vortex filaments in the electron magnetohydrodynamic (EMH) model for the unbounded plane under strong magnetic confinement. We derive the specific heat using a steepest descent method and a mean field property. Our derivations show that as temperature increases, the overall size of the system increases exponentially and the energy drops. The implication of negative specific heat is a runaway reaction, resulting in a collapsing inner core surrounded by an expanding halo of filaments.

  10. Spatially resolved penetration depth measurements and vortex manipulation in the ferromagnetic superconductor ErNi2B2C

    DOE Public Access Gateway for Energy & Science Beta (PAGES Beta)

    Wulferding, Dirk; Yang, Ilkyu; Yang, Jinho; Lee, Minkyung; Choi, Hee Cheul; Bud'ko, Sergey L.; Canfield, Paul C.; Yeom, Han Woong; Kim, Jeehoon

    2015-07-31

    We present a local probe study of the magnetic superconductor ErNi2B2C, using magnetic force microscopy at sub-Kelvin temperatures. ErNi2B2C is an ideal system to explore the effects of concomitant superconductivity and ferromagnetism. At 500 mK, far below the transition to a weakly ferromagnetic state, we directly observe a structured magnetic background on the micrometer scale. We determine spatially resolved absolute values of the magnetic penetration depth ? and study its temperature dependence as the system undergoes magnetic phase transitions from paramagnetic to antiferromagnetic, and to weak ferromagnetic, all within the superconducting regime. We estimate the absolute pinning force of Abrikosovmore »vortices, which shows a position dependence and temperature dependence as well, and discuss the possibility of the purported spontaneous vortex formation.« less

  11. Laser stabilization using spectral hole burning

    E-Print Network [OSTI]

    L. Rippe; B. Julsgaard; A. Walther; S. Kröll

    2006-11-05

    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.

  12. RF-Photonic Frequency Stability Gear Box

    E-Print Network [OSTI]

    Matsko, Andrey B; Ilchenko, Vladimir S; Seidel, David; Maleki, Lute

    2011-01-01

    An optical technique based on stability transfer among modes of a monolithic optical microresonator is proposed for long therm frequency stabilization of a radiofrequency (RF) oscillator. We show that locking two resonator modes, characterized with dissimilar sensitivity in responding to an applied forcing function, to a master RF oscillator allows enhancing the long term stability of a slave RF oscillator locked to two resonator modes having nearly identical sensitivity. For instance, the stability of a 10 MHz master oscillator characterized with Allan deviation of 10^-7 at 10^4s can be increased and transferred to a slave oscillator with identical stability performance, so that the resultant Allan deviation of the slave oscillator becomes equal to 10-13 at 10^4s. The method does not require absolute frequency references to achieve such a performance.

  13. Can the correlated stability conjecture be saved?

    E-Print Network [OSTI]

    Alex Buchel; Alexander Patrushev

    2011-06-10

    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.

  14. Model for characterization of a vortex pair formed by shock passage over a light-gas inhomogeneity

    SciTech Connect (OSTI)

    Yang, J.; Kubota, T.; Zukoski, E.E.

    1994-01-01

    This work investigates the two-dimensional flow of a shock wave over a circular light-gas inhomogeneity in a channel with finite width. The pressure gradient from the shock wave interacts with the density gradient at the edge of the inhomogeneity to deposit vorticity around the perimeter, and the structure rolls up into a pair of counter-rotating vortices. The aim of this study is to develop an understanding of the scaling laws for the flow field produced by this interaction at times long after the passage of the shock across the inhomogeneity. Numerical simulations are performed for various initial conditions and the results are used to guide the development of relatively simple algebraic models that characterize the dynamics of the vortex pair, and that allow extrapolation of the numerical results to conditions more nearly of interest in practical situations. The models are not derived directly from the equations of motion but depend on these equations and on intuition guided by the numerical results. Agreement between simulations and models is generally good except for a vortex-spacing model which is less satisfactory. A practical application of this shock-induced vortical flow is rapid and efficient mixing of fuel and oxidizer in a SCRAMJET combustion chamber. One possible injector design uses the interaction of an oblique shock wave with a jet of light fuel to generate vorticity which stirs and mixes the two fluids and lifts the burning jet away from the combustor wall. Marble proposed an analogy between this three-dimensional steady flow and the two-dimensional unsteady problem of the present investigation. Comparison is made between closely corresponding three-dimensional steady and two-dimensional unsteady flows, and a mathematical description of Marble`s analogy is proposed. 17 refs.

  15. Pipe crawler with stabilizing midsection

    DOE Patents [OSTI]

    Zollinger, W.T.; Treanor, R.C.

    1994-12-27

    A pipe crawler is described having a midsection that provides the stability and flexibility to allow the pipe crawler to negotiate curved and uneven segments of piping while traveling through piping systems. The pipe crawler comprises a front leg assembly, a rear leg assembly, a midsection with a gimbal at each end for connecting the midsection to the front and rear leg assemblies in a flexible manner, and an air cylinder for changing the distance between the front and rear leg assemblies. The pipe crawler moves in ''inch worm'' fashion with the front and rear leg assemblies alternating between an extended and a retracted position as the air cylinder moves the retracted leg assembly forward. The midsection has a plurality of legs extending radially for holding the midsection within a maximum displacement from the piping axis so that the gimbals are not pivoted to extreme angles where they might lock up or seize. When the midsection is displaced sufficiently, its legs with wheels on each end engage the interior surface of the piping and prevent further displacement. Using two gimbals divides the angle between the planes defined by the front and rear leg assemblies which also helps to prevent excessive gimbal pivoting. 5 figures.

  16. Thermal Stability Of Formohydroxamic Acid

    SciTech Connect (OSTI)

    Fondeur, F. F.; Rudisill, T. S.

    2011-10-21

    The thermal stability of formohydroxamic acid (FHA) was evaluated to address the potential for exothermic decomposition during storage and its use in the uranium extraction process. Accelerating rate calorimetry showed rapid decomposition at a temperature above 65 {degree}?C; although, the rate of pressure rise was greater than two orders of magnitude less than the lower bound for materials which have no explosive properties with respect to transportation. FHA solutions in water and nitric acid did not reach runaway conditions until 150 {degree}?C. Analysis by differential scanning calorimetry showed that FHA melted at 67 {degree}?C and thermally decomposed at 90 {degree}?C with an enthalpy of -1924 J/g. The energics of the FHA thermal decomposition are comparable to those measured for aqueous solutions of hydroxylamine nitrate. Solid FHA should be stored in a location where the temperature does not exceed 20-25 {degree}?C. As a best practice, the solid material should be stored in a climate-controlled environment such as a refrigerator or freezer. FHA solutions in water are not susceptible to degradation by acid hydrolysis and are the preferred way to handle FHA prior to use.

  17. Process for stabilization of coal liquid fractions

    DOE Patents [OSTI]

    Davies, Geoffrey (Boston, MA); El-Toukhy, Ahmed (Alexandria, EG)

    1987-01-01

    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.

  18. Jacobi stability analysis of the Lorenz system

    E-Print Network [OSTI]

    Tiberiu Harko; Chor Yin Ho; Chun Sing Leung; Stan Yip

    2015-04-11

    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.

  19. FORMATION OF COLLOIDAL CRYSTALS FROM NANOPARTICLE STABILIZED COLLOIDAL SUSPENSIONS

    E-Print Network [OSTI]

    Braun, Paul

    FORMATION OF COLLOIDAL CRYSTALS FROM NANOPARTICLE STABILIZED COLLOIDAL SUSPENSIONS BY WENDY WOONYEE.....................................................................8 2.2 Colloid Stability in Suspension .......................................................................................9 2.3 Nanoparticle-Stabilized Colloidal Suspensions...............................................13

  20. Long life lithium batteries with stabilized electrodes

    DOE Patents [OSTI]

    Amine, Khalil (Downers Grove, IL); Liu, Jun (Naperville, IL); Vissers, Donald R. (Naperville, IL); Lu, Wenquan (Darien, IL)

    2009-03-24

    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.

  1. Formation and Stability of Impurity "Snakes" in Tokamak Plasmas...

    Office of Scientific and Technical Information (OSTI)

    Formation and Stability of Impurity "Snakes" in Tokamak Plasmas Citation Details In-Document Search Title: Formation and Stability of Impurity "Snakes" in Tokamak Plasmas Authors:...

  2. Stabilizing Topological Phases in Graphene via Random Adsorption...

    Office of Scientific and Technical Information (OSTI)

    Stabilizing Topological Phases in Graphene via Random Adsorption Prev Next Title: Stabilizing Topological Phases in Graphene via Random Adsorption Authors: Jiang, Hua ; Qiao,...

  3. Design and control of a passively stabilized multimodal hopping robot

    E-Print Network [OSTI]

    Pantel, Erica

    2010-01-01

    Stabilized Multimodal Hopping Robot A Thesis submitted inStabilized Multimodal Hopping Robot by Erica Pantel Masterfor a multimodal hopping robot. The robot harnesses passive

  4. Quality, Stability, Performance, and Emission Impacts of Biodiesel...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Stability, Performance, and Emission Impacts of Biodiesel Blends Quality, Stability, Performance, and Emission Impacts of Biodiesel Blends Presentation from the U.S. DOE Office of...

  5. Probative Investigation of the Thermal Stability of Wastes Involved...

    Office of Environmental Management (EM)

    the Thermal Stability of Wastes Involved in February 2014 Waste Isolation Pilot Plant (WIPP) Waste Drum Breach Event Probative Investigation of the Thermal Stability of Wastes...

  6. 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...

  7. Pyrolysis of Yttria Stabilized Zirconia and its Characterization

    E-Print Network [OSTI]

    FARSHIHAGHRO, EBRAHIM

    2013-01-01

    to produce Yttrium stabilized Zirconia is introduced and theused methods for synthesizing zirconia nanoparticles areyttrium stabilized zirconia is analyzed. Generally, there

  8. Scale-Up of Magnesium Production by Fully Stabilized Zirconia...

    Office of Energy Efficiency and Renewable Energy (EERE) Indexed Site

    Up of Magnesium Production by Fully Stabilized Zirconia Electrolysis Scale-Up of Magnesium Production by Fully Stabilized Zirconia Electrolysis 2012 DOE Hydrogen and Fuel Cells...

  9. 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,...

  10. ORIGINAL ARTICLE Pneumatic Energy Sources for Autonomous

    E-Print Network [OSTI]

    Wood, Robert

    inspired by structures found in nature.1­5 As comple- mentary technologies to traditional robotics, mobile- matic energy sources and scaling laws for their use in mobile applications. If one simply selects sources and review their relative merits. We evaluate commercially available battery

  11. Pneumatic vibratory cleaner conveyor for sugarcane 

    E-Print Network [OSTI]

    Oliveira, Roberto Costa de

    1983-01-01

    physical positions, each of which demand a particular set of equations of motion. Those billet physical positions are: 1. Friction with the conveyor bed. 2. Impact on the flap. 3. F iction with the flap without influence of air jet. 4. Free flight. 5... the system of the three equations [31], [32] and [33] for the three unknowns yields: ()* = [rP + 2(s-x)] I 3r [34] z* = s ? rP* [36] y* = sy [36] With these results, the no slip assumption can be tested: F . . = ~F x n~ & uF n friction where F...

  12. Pneumatic starter for internal combustion engine

    SciTech Connect (OSTI)

    Kristof, J.J.; Elwer, M.

    1989-07-11

    A starter arrangement for an engine is described which consists of: a fluid actuated rotary vane motor which is adapted to engage an associated engine, the rotary motor having a hub and at least one blade which is slidably mounted in the hub and is made from a fiber reinforced plastic material to reduce friction, and wherein at least one blade has a wear surface made of the same material; a housing including a sleeve in which the rotary motor is positioned, the sleeve having on its inner surface a hard metallic coating to reduce friction, wherein the sleeve inner surface coating comprises a chromium electrocuting having a hardness which measures at least 70 on the Rockwell C hardness scale and a microfinish of less than 10 micro-inches R.M.S.; and, a relay valve means for selectively providing a pressurized operating fluid to the rotary motor, wherein the blade material and the sleeve inner surface coating cooperate to enable the motor to rotate in the sleeve with a minimum of friction thereby obviating the need for a lubricating system for the starter arrangement.

  13. Pneumatic starter for internal combustion engine

    SciTech Connect (OSTI)

    Kristoff, J.J.; Elwer, M.

    1992-05-12

    This patent describes a starter arrangement for an engine. It comprises a fluid actuated rotary vane motor which is adapted to engage an associated engine, the rotary motor having a hub and at least one blade which is slidably mounted in the hub and is made from a fiber reinforced plastic material to reduce friction, and wherein the at least one blade has a wear surface made of the same material; a housing including a sleeve in which the rotary motor is positioned, (a relay valve means for selectively providing a pressurized operating fluid to the rotary motor,) wherein the blade material and the sleeve inner surface coating cooperate to enable the motor to rotate in the sleeve with a minimum of friction thereby obviating the need for a lubricating system for the starter arrangement.

  14. Pneumatic wall-locking geophone system

    DOE Patents [OSTI]

    Kuhlman, Harland L. (Minneapolis, MN); Cumerlato, Calvin L. (Minneapolis, MN); Tweeton, Daryl R. (Apple Valley, MN)

    1991-01-01

    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.

  15. Pneumatic Conveyance Device - Energy Innovation Portal

    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: Alternative Fuels Data Center Homesum_a_epg0_fpd_mmcf_m.xls" ,"Available from WebQuantityBonneville Power Administration wouldMass mapSpeeding access| DepartmentPeerFederalPlatinumtake the 2011|

  16. What does stabilizing greenhouse gas concentrations mean?

    E-Print Network [OSTI]

    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 ...

  17. Experimental characterization of foam drainage and stability 

    E-Print Network [OSTI]

    Sheth, Vikas Rameshchandra

    1993-01-01

    A novel experimental procedure to characterize the stability of foams is established. The procedure involves the unsteady state drainage of liquid from a stationary foam due to an applied pressure difference (forced drainage)- Unlike other bulk...

  18. 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...

  19. Singlet-Stabilized Minimal Gauge Mediation

    E-Print Network [OSTI]

    David Curtin; Yuhsin Tsai

    2011-04-27

    We propose Singlet Stabilized Minimal Gauge Mediation as a simple ISS-based model of Direct Gauge Mediation which avoids both light gauginos and Landau poles. The hidden sector is a massive s-confining SQCD that is distinguished by a minimal SU(5) flavor group. The uplifted vacuum is stabilized by coupling the meson to an additional singlet sector with its own U(1) gauge symmetry via non-renormalizable interactions suppressed by a higher scale Lambda_UV in the electric theory. This generates a nonzero VEV for the singlet meson via the inverted hierarchy mechanism, but requires tuning to a precision ~ (Lambda/Lambda_UV)^2, which is ~ 10^{-4}. In the course of this analysis we also outline some simple model-building rules for stabilizing uplifted ISS models, which lead us to conclude that meson deformations are required (or at least heavily favored) to stabilize the adjoint component of the magnetic meson.

  20. Singlet-Stabilized Minimal Gauge Mediation

    E-Print Network [OSTI]

    Curtin, David

    2010-01-01

    We propose Singlet Stabilized Minimal Gauge Mediation as a simple ISS-based model of Direct Gauge Mediation which avoids both light gauginos and Landau poles. The hidden sector is a massive s-confining SQCD that is distinguished by a minimal SU(5) flavor group. The uplifted vacuum is stabilized by coupling the meson to an additional singlet sector with its own U(1) gauge symmetry via non-renormalizable interactions suppressed by a higher scale Lambda_UV in the electric theory. This generates a nonzero VEV for the singlet meson via the inverted hierarchy mechanism, but requires tuning to a precision ~ (Lambda/Lambda_UV)^2, which is ~ 10^{-4}. In the course of this analysis we also outline some simple model-building rules for stabilizing uplifted ISS models, which lead us to conclude that meson deformations are required (or at least heavily favored) to stabilize the adjoint component of the magnetic meson.

  1. Influence of Motion Cueing on Helicopter Stabilization

    E-Print Network [OSTI]

    Influence of Motion Cueing on Helicopter Stabilization Daniel R. Berger, Cengiz Terzibas, and Heinrich H. Bülthoff Max Planck Institute for Biological Cybernetics, Tübingen, Germany Helicopters vestibular and somatosensory cues. To test this hypothesis, we measured helicopter hovering performance

  2. Discontinuous Lyapunov Functions for Nonasymptotic Stability Analysis

    E-Print Network [OSTI]

    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

  3. Rocky Flats Ash test procedure (sludge stabilization)

    SciTech Connect (OSTI)

    Funston, G.A.

    1995-06-14

    Rocky Flats Ash items have been identified as the next set of materials to be stabilized. This test is being run to determine charge sizes and soak times to completely stabilize the Rocky Flats Ash items. The information gathered will be used to generate the heating rampup cycle for stabilization. The test will provide information to determine charge sizes, soak times and mesh screen sizes (if available at time of test) for stabilization of Rocky Flats Ash items to be processed in the HC-21C Muffle Furnace Process. Once the charge size and soak times have been established, a program for the temperature controller of the HC-21C Muffle Furnace process will be generated for processing Rocky Flats Ash.

  4. Automatic Stability Checking for Large Analog Circuits 

    E-Print Network [OSTI]

    Mukherjee, Parijat 1985-

    2010-12-06

    Small signal stability has always been an important concern for analog designers. Recent advances such as the Loop Finder algorithm allows designers to detect and identify local, potentially unstable return loops without ...

  5. Sulfate induced heave in lime stabilized soil 

    E-Print Network [OSTI]

    Bredenkamp, Sanet

    1994-01-01

    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 ...

  6. Classical and thermodynamic stability of black holes

    E-Print Network [OSTI]

    Ricardo Monteiro

    2010-06-28

    We consider the stability of black holes within both classical general relativity and the semiclassical thermodynamic description. In particular, we study linearised perturbations and their contribution to the gravitational partition function, addressing technical issues for charged (Reissner-Nordstrom) and rotating (Kerr-AdS) black holes. Exploring the connection between classical and thermodynamic stability, we find classical instabilities of Myers-Perry black holes and bifurcations to new black hole families.

  7. Engineering report (conceptual design) PFP solution stabilization

    SciTech Connect (OSTI)

    Witt, J.B.

    1997-07-17

    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.

  8. Stabilized fuel with silica support structure

    SciTech Connect (OSTI)

    Poco, J.F.; Hrubesh, L.W.

    1991-12-31

    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.

  9. A model study of articulated mat stability 

    E-Print Network [OSTI]

    Sasaki, Tetsu

    1990-01-01

    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...

  10. Further Results on Finite-Time Partial Stability and Stabilization. Applications to Nonlinear Control Systems

    SciTech Connect (OSTI)

    Jammazi, Chaker [Faculte des Sciences de Bizerte Departement de Mathematiques Laboratoire LIM Ecole Polytechnique de Tunisie (Tunisia)

    2009-03-05

    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.

  11. Physics Issues Worshop Summary (energetic beams, flow, stability)

    E-Print Network [OSTI]

    Washington at Seattle, University of

    Physics Issues Worshop Summary (energetic beams, flow, stability) FRC stability Global stability remains the leading issue affecting the future of FRC research. It must be resolved before the fusion community will embrace FRC as not just an entertaining toy, but a bona fide fusion concept. The stability

  12. On the applicability of local asymptotic stability criteria to stellarator stability

    E-Print Network [OSTI]

    Tatsuno, Tomoya

    On the applicability of local asymptotic stability criteria to stellarator stability B. A. Carreras, Kyoto, Japan T. Tatsuno Tokyo University, Tokyo, Japan Received 22 November 2000; accepted 12 December be the existence of local flattening of the pressure profile at the resonant surfaces. This local flattening

  13. Process for stabilizing the viscosity characteristics of coal derived materials and the stabilized materials obtained thereby

    DOE Patents [OSTI]

    Bronfenbrenner, James C. (Allentown, PA); Foster, Edward P. (Allentown, PA); Tewari, Krishna (Allentown, PA)

    1985-01-01

    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.

  14. The (In)Stability of Planetary Systems

    E-Print Network [OSTI]

    Rory Barnes; Thomas Quinn

    2004-01-09

    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.

  15. Stability Study of the RERTR Fuel Microstructure

    SciTech Connect (OSTI)

    Jian Gan; Dennis Keiser; Brandon Miller; Daniel Wachs

    2014-04-01

    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.

  16. Stability and dynamics of magnetocapillary interactions

    E-Print Network [OSTI]

    Rujeko Chinomona; Janelle Lajeunesse; William H. Mitchell; Yao Yao; Saverio E. Spagnolie

    2014-12-16

    Recent experiments have shown that floating ferromagnetic beads, under the influence of an oscillating background magnetic field, can move along a liquid-air interface in a sustained periodic locomotion [Lumay et al., Soft Matter, 2013, 9, 2420]. Dynamic activity arises from a periodically induced dipole-dipole repulsion between the beads acting in concert with capillary attraction. We investigate analytically and numerically the stability and dynamics of this magnetocapillary swimming, and explore other related topics including the steady and periodic equilibrium configurations of two and three beads, and bead collisions. The swimming speed and system stability depend on a dimensionless measure of the relative repulsive and attractive forces which we term the magnetocapillary number. An oscillatory magnetic field may stabilize an otherwise unstable collinear configuration, and striking behaviors are observed in fast transitions to and from locomotory states, offering insight into the behavior and self-assembly of interface-bound micro-particles.

  17. Wind Power Plant Voltage Stability Evaluation: Preprint

    SciTech Connect (OSTI)

    Muljadi, E.; Zhang, Y. C.

    2014-09-01

    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.

  18. Image Registration for Stability Testing of MEMS

    E-Print Network [OSTI]

    Memarsadeghi, Nargess; Blake, Peter N; Morey, Peter A; Landsman, Wayne B; Chambers, Victor J; Moseley, Samuel H; 10.1117/12.872076

    2013-01-01

    Image registration, or alignment of two or more images covering the same scenes or objects, is of great interest in many disciplines such as remote sensing, medical imaging, astronomy, and computer vision. In this paper, we introduce a new application of image registration algorithms. We demonstrate how through a wavelet based image registration algorithm, engineers can evaluate stability of Micro-Electro-Mechanical Systems (MEMS). In particular, we applied image registration algorithms to assess alignment stability of the MicroShutters Subsystem (MSS) of the Near Infrared Spectrograph (NIRSpec) instrument of the James Webb Space Telescope (JWST). This work introduces a new methodology for evaluating stability of MEMS devices to engineers as well as a new application of image registration algorithms to computer scientists.

  19. Renewable source controls for grid stability.

    SciTech Connect (OSTI)

    Byrne, Raymond Harry; Elliott, Ryan Thomas; Neely, Jason C.; Silva Monroy, Cesar Augusto; Schoenwald, David Alan; Grant, Lisa

    2012-12-01

    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.

  20. Fluid sphere: stability problem and dimensional constraint

    E-Print Network [OSTI]

    Farook Rahaman; Anirudh Pradhan; Nasr Ahmed; Saibal Ray; Bijan Saha; Mosiur Rahaman

    2015-04-14

    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.

  1. Reducing Greenhouse Gas Emissions for Climate Stabilization

    E-Print Network [OSTI]

    Thomas, David D.

    Reducing Greenhouse Gas Emissions for Climate Stabilization: Framing Regional Options L A U R A S C reduction of global greenhouse gas (GHG) emissions by as much as 80% by 2050. Subnational efforts to cut The call to cut global greenhouse gas (GHG) emissions by up to 80% below 2000 levels, which researchers

  2. of Flow on Morphological Stability Directional Solidification

    E-Print Network [OSTI]

    Schulze, Tim

    Effects During of Flow on Morphological Stability Directional Solidification S.H. DAVIS and T.P. SCHULZE Research involving the interaction of flow with morphological instability during directional solidifi- cation of binary alloys is reviewed. In general, flow may arise during the solidification process

  3. Stability of discrete breathers in magnetic metamaterials

    E-Print Network [OSTI]

    Pelinovsky, Dmitry

    Stability of discrete breathers in magnetic metamaterials Dmitry Pelinovsky1 and Vassilis Rothos2 1 describing magnetic metamaterials which consist of periodic arrays of split- ring resonators [4, 7]: ¨qn + V criterion to the multi-site breathers in magnetic metamaterials. 2 Formalism In what follows, we shall use

  4. GEOPHYSICS FOR SLOPE STABILITY ROBERT HACK

    E-Print Network [OSTI]

    Hack, Robert

    GEOPHYSICS FOR SLOPE STABILITY ROBERT HACK Section Engineering Geology, Centre for Technical-mail: hack@itc.nl (Received 2 June, 2000; Accepted 4 September, 2000) Abstract. A pre-requisite in slope Publishers. Printed in the Netherlands. #12;424 ROBERT HACK the slope material with, for example, manganese

  5. Stability and folds in an elastocapillary system

    E-Print Network [OSTI]

    Amir Akbari; Reghan J. Hill; Theo G. M. van de Ven

    2015-05-27

    We examine the equilibrium and stability of an elastocapillary system to model drying-induced structural failures. The model comprises a circular elastic membrane with a hole at the center that is deformed by the capillary pressure of simply connected and doubly connected menisci. Using variational and spectral methods, stability is related to the slope of equilibrium branches in the liquid content versus pressure diagram for the constrained and unconstrained problems. The second-variation spectra are separately determined for the membrane and meniscus, showing that the membrane out-of-plane spectrum and the in-plane spectrum at large elatocapillary numbers are both positive, so that only meniscus perturbations can cause instability. At small elastocapillary numbers, the in-plane spectrum has a negative eigenvalue, inducing wrinkling instabilities in thin membranes. In contrast, the smallest eigenvalue of the meniscus spectrum always changes sign at a pressure turning point where stability exchange occurs in the unconstrained problem. We also examine configurations in which the meniscus and membrane are individually stable, while the elastocapillary system as a whole is not; this emphasizes the connection between stability and the coupling of elastic and capillary forces.

  6. Hydrothermal stability of high silica zeolites 

    E-Print Network [OSTI]

    Young, David

    1988-01-01

    This thesis concerns the hydrothermal stability of two zeolite molecular sieves with the MFI structure, ZSM-5 and its 'aluminium free' form silicalite. Silicalite was synthesised from low pH alkali metal free aqueous gels at 95°C and characterised...

  7. Amphiphiles for protein solubilization and stabilization

    DOE Patents [OSTI]

    Gellman, Samuel Helmer; Chae, Pil Seok; Laible, Phillip D; Wander, Marc J

    2014-11-04

    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.

  8. Stability of AdS black strings

    E-Print Network [OSTI]

    T. Delsate

    2008-08-14

    We review the recent developements in the stability problem and phase diagram for asymptotically locally $AdS$ black strings. First, we quickly review the case of locally flat black string before turning to the case of locally $AdS$ spacetimes.

  9. Enhancing Power Grid Stability through Analytics

    E-Print Network [OSTI]

    Lakoba, Taras I.

    Enhancing Power Grid Stability through Analytics: Information is Power, and Power is Information no dummies). · But... many challenges in the North American power grid revolve around coordinating? Power is Information · Refrain in many quarters of the power grid today says that we must "extract

  10. White Oak Dam stability analysis. Volume I

    SciTech Connect (OSTI)

    Ahmed, S.B.

    1994-01-01

    A parametric study was conducted to evaluate the stability of the White Oak Dam (WOD) embankment and foundation. Slope stability analyses were performed for the upper and lower bound soil properties at three sections of the dam using the PCSTABL4 computer program. Minimum safety factors were calculated for the applicable seismic and static loading conditions. Liquefaction potential of the dam embankment and foundation solid during the seismic event was assessed by using simplified procedures. The WOD is classified as a low hazard facility and the Evaluation Basis Earthquake (EBE) is defined as an earthquake with a magnitude of m{sub b} = 5.6 and a Peak Ground Accelerator (PGA) of 0.13 g. This event is approximately equivalent to a Modified Mercalli Intensity of VI-VIII. The EBE is used to perform the seismic evaluation for slope stability and liquefaction potential. Results of the stability analyses and the liquefaction assessment lead to the conclusion that the White Oak Dam is safe and stable for the static and the seismic events defined in this study. Ogden Environmental, at the request of MMES, has checked and verified the calculations for the critical loading conditions and performed a peer review of this report. Ogden has determined that the WOD is stable under the defined static and seismic loading conditions and the embankment materials are in general not susceptible to liquefaction.

  11. Melt dumping in string stabilized ribbon growth

    DOE Patents [OSTI]

    Sachs, Emanuel M. (42 Old Middlesex Rd., Belmont, MA 02178)

    1986-12-09

    A method and apparatus for stabilizing the edge positions of a ribbon drawn from a melt includes the use of wettable strings drawn in parallel up through the melt surface, the ribbon being grown between the strings. A furnace and various features of the crucible used therein permit continuous automatic growth of flat ribbons without close temperature control or the need for visual inspection.

  12. http://www.pppl.gov Stabilization

    E-Print Network [OSTI]

    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

  13. Amphiphiles for protein solubilization and stabilization

    DOE Patents [OSTI]

    Gellman, Samuel Helmer; Chae, Pil Seok; Laible, Philip D.; Wander, Marc J.

    2012-09-11

    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.

  14. Improving Vortex Generators to Enhance the Performance of Air-Cooled Condensers in a Geothermal Power Plant

    SciTech Connect (OSTI)

    Manohar S. Sohal

    2005-09-01

    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.

  15. Foams Stabilized by Tricationic Amphiphilic Surfactants

    E-Print Network [OSTI]

    Seth Heerschap; John N. Marafino; Kristin McKenna; Kevin L. Caran; Klebert Feitosa

    2015-09-11

    The unique surface properties of amphiphilic molecules have made them widely used in applications where foaming, emulsifying or coating processes are needed. Novel surfactant architectures with multi-cephalic and multi-tailed molecules have reportedly enhanced their anti-bacterial activity in connection with tail length and the nature of the head group, but their ability to produce and stabilize foam is mostly unknown. Here we report on experiments with tris-cationic, triple-headed, double- and single-tailed amphiphiles and their foamability and foam stability with respect to head group, tail number and tail length. The amphiphiles are composed of an aromatic mesitylene core and three benzylic amonium bromide groups, with alkyl chains attached to one or two of the head groups. Whereas shorter (14 carbons in length) double-tailed molecules are found to produce very stable foams, foams made with single tail molecules of the same length show poor foamability and stability, and foams with longer (16 carbons in length) double-tail molecules do not foam with the methods used. By contrast, the structure of the non-tail-bearing head group (trimethylammonium vs. pyridinium) has no impact on foamability. Furthermore, observations of the coarsening rate at nearly constant liquid content indicate that the enhanced foam stability is a result of lower gas permeability through the surfactant monolayer. Finally, the critical aggregation concentration (CAC) of the surfactants demonstrates to be a good predictor of foamability and foam stability for these small molecule surfactants. This results inform how surfactant architecture can be tailored to produce stable foams.

  16. Safety evaluation of interim stabilization of non-stabilized single-shell watch list tanks

    SciTech Connect (OSTI)

    Stahl, S.M.

    1994-12-30

    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.

  17. A survey of ideal fluid propeller theories and a study of the effects of aerodynamic propeller loading on trailing vortex induced velocity and thrust 

    E-Print Network [OSTI]

    Kelley, Edward Madison

    1969-01-01

    A SURVEY OF IDEAL FLUID PRO~ THEORIES AND A STUIE OP THE EFFECTS OF AERODYNAMIC PRO~ LOADING ON TRAILING VORTEX INDUCED VELOCITY AND THRUST A Thesis EDWARD MADISON ~ Suhmitted to the Graduate College of Texas A&M University in Partial... VELOCITY AND THRUST A Thesis by EDWARD MADISON HELLEY Approsed as to sty1e and content 'by: Head of epartment i%. mbe August 1969 111 ABSTRACT A Survey of Ideal Fluid Propeller Theories and a Study of the Ei'fects of Aerodynamic Propeller...

  18. Fourier-Mukai transforms and stability conditions on abelian threefolds 

    E-Print Network [OSTI]

    Piyaratne, Hathurusinghege Dulip Bandara

    2014-11-27

    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 ...

  19. Stability analysis for class of switched nonlinear systems

    E-Print Network [OSTI]

    Shaker, Hamid Reza

    Stability analysis for a class of switched nonlinear systems is addressed in this paper. Two linear matrix inequality (LMI) based sufficient conditions for asymptotic stability are proposed for switched nonlinear systems. ...

  20. Stability of Biodiesel and Biodiesel Blends: Interim Report

    SciTech Connect (OSTI)

    McCormick, R. L.; Alleman, T. L.; Waynick, J. A.; Westbrook, S. R.; Porter, S.

    2006-04-01

    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.

  1. Relation between viscosity and stability for heavy oil emulsions 

    E-Print Network [OSTI]

    Ye, Sherry Qianwen

    1998-01-01

    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, ...

  2. Upper bounds on minimum distance of nonbinary quantum stabilizer codes 

    E-Print Network [OSTI]

    Kumar, Santosh

    2005-11-01

    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...

  3. Sufficient Conditions for Uniform Stability of Regularization Algorithms

    E-Print Network [OSTI]

    Poggio, Tomaso

    2009-12-01

    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: ...

  4. Exploiting Elements of Transcriptional Machinery to Enhance Protein Stability

    E-Print Network [OSTI]

    Love, John J.

    Exploiting Elements of Transcriptional Machinery to Enhance Protein Stability Nora H. Barakat Ltd. All rights reserved. *Corresponding author Keywords: protein design; protein stability of protein design aspires to engineer proteins of specific function. Function is correlated directly

  5. Thermodynamic stability of actinide pyrochlore minerals in deep...

    Office of Scientific and Technical Information (OSTI)

    SCIENCE; HIGH-LEVEL RADIOACTIVE WASTES; PLUTONIUM; PYROCHLORE; STABILITY; THERMODYNAMICS; WASTE FORMS; RADIOACTIVE WASTE DISPOSAL; BACKFILLING; RADIOACTIVE WASTE...

  6. Lyapunov stability of flowing magnetohydrodynamic plasmas surrounded by resistive walls

    SciTech Connect (OSTI)

    Tasso, H. [Max-Planck-Institut fuer Plasmaphysik, Euratom Association, 85748 Garching (Germany); Throumoulopoulos, G. N. [Association Euratom-Hellenic Republic, Department of Physics, University of Ioannina, GR 451 10 Ioannina (Greece)

    2011-07-15

    A general stability condition for plasma-vacuum systems with resistive walls is derived by using the Frieman Rotenberg Lagrangian stability formulation [Rev. Mod. Phys. 32, 898 (1960)]. It is shown that the Lyapunov stability limit for external modes does not depend upon the gyroscopic term but upon the sign of the perturbed potential energy only. In the absence of dissipation in the plasma such as viscosity, it is expected that the flow cannot stabilize the system.

  7. System Design Description PFP Thermal Stabilization

    SciTech Connect (OSTI)

    RISENMAY, H.R.

    2000-04-25

    The purpose of this document is to provide a system design description (SDD) and design basis for the Plutonium Finishing Plant (PFP) Thermal Stabilization project. The chief objective of the SDD is to document the Structures, Systems, and Components (SSCs) that establish and maintain the facility Safety Envelope necessary for normal safe operation of the facility; as identified in the FSAR, the OSRs, and Safety Assessment Documents (SADs). This safety equipment documentation should satisfy guidelines for the SDD given in WHC-SD-CP-TI-18 1, Criteria for Identification and Control of Equipment Necessary for Preservation of the Safety Envelope and Safe Operation of PFP. The basis for operational, alarm response, maintenance, and surveillance procedures are also identified and justified in this document. This document and its appendices address the following elements of the PFP Thermal Stabilization project: Functional and design requirements; Design description; Safety Envelope Analysis; Safety Equipment Class; and Operational, maintenance and surveillance procedures.

  8. Switching Quantum Dynamics for Fast Stabilization

    E-Print Network [OSTI]

    Pierre Scaramuzza; Francesco Ticozzi

    2015-04-16

    Control strategies for dissipative preparation of target quantum states, both pure and mixed, and subspaces are obtained by switching between a set of available semigroup generators. We show that the class of problems of interest can be recast, from a control--theoretic perspective, into a switched-stabilization problem for linear dynamics. This is attained by a suitable affine transformation of the coherence-vector representation. In particular, we propose and compare stabilizing time-based and state-based switching rules for entangled state preparation, showing that the latter not only ensure faster convergence with respect to non-switching methods, but can designed so that they retain robustness with respect to initialization, as long as the target is a pure state or a subspace.

  9. Theory and modelling of nanocarbon phase stability.

    SciTech Connect (OSTI)

    Barnard, A. S.

    2006-01-01

    The transformation of nanodiamonds into carbon-onions (and vice versa) has been observed experimentally and has been modeled computationally at various levels of sophistication. Also, several analytical theories have been derived to describe the size, temperature and pressure dependence of this phase transition. However, in most cases a pure carbon-onion or nanodiamond is not the final product. More often than not an intermediary is formed, known as a bucky-diamond, with a diamond-like core encased in an onion-like shell. This has prompted a number of studies investigating the relative stability of nanodiamonds, bucky-diamonds, carbon-onions and fullerenes, in various size regimes. Presented here is a review outlining results of numerous theoretical studies examining the phase diagrams and phase stability of carbon nanoparticles, to clarify the complicated relationship between fullerenic and diamond structures at the nanoscale.

  10. Plutonium stabilization and handling (PuSH)

    SciTech Connect (OSTI)

    Weiss, E.V.

    1997-01-23

    This Functional Design Criteria (FDC) addresses construction of a Stabilization and Packaging System (SPS) to oxidize and package for long term storage remaining plutonium-bearing special nuclear materials currently in inventory at the Plutonium Finishing Plant (PFP), and modification of vault equipment to allow storage of resulting packages of stabilized SNM for up to fifty years. The major sections of the project are: site preparation; SPS Procurement, Installation, and Testing; storage vault modification; and characterization equipment additions. The SPS will be procured as part of a Department of Energy nationwide common procurement. Specific design crit1460eria for the SPS have been extracted from that contract and are contained in an appendix to this document.

  11. Moduli stabilization with Fayet-Iliopoulos uplift

    E-Print Network [OSTI]

    E. Dudas; Y. Mambrini; S. Pokorski; A. Romagnoni

    2007-11-30

    In the recent years, phenomenological models of moduli stabilization were proposed, where the dynamics of the stabilization is essentially supersymmetric, whereas an O'Rafearthaigh supersymmetry breaking sector is responsible for the "uplift" of the cosmological constant to zero. We investigate the case where the uplift is provided by a Fayet-Iliopoulos sector. We find that in this case the modulus contribution to supersymmetry breaking is larger than in the previous models. A first consequence of this class of constructions is for gauginos, which are heavier compared to previous models. In some of our explicit examples, due to a non-standard gauge-mediation type negative contribution to scalars masses, the whole superpartner spectrum can be efficiently compressed at low-energy. This provides an original phenomenology testable at the LHC, in particular sleptons are generically heavier than the squarks.

  12. On Stabilization of Nonautonomous Nonlinear Systems

    SciTech Connect (OSTI)

    Bogdanov, A. Yu. [Faculty of Mathematics and IT, Ulyanovsk State University, 42 Leo Tolstoy str., Ulyanovsk, 432970 (Russian Federation)

    2008-10-30

    The procedures to obtain the sufficient conditions of asymptotic stability for nonlinear nonstationary continuous-time systems are discussed. We consider different types of the following general controlled system: x = X(t,x,u) = F(t,x)+B(t,x)u, x(t{sub 0}) = x{sub 0}. (*) The basis of investigation is limiting equations, limiting Lyapunov functions, etc. The improved concept of observability of the pair of functional matrices is presented. By these results the problem of synthesis of asymptotically stable control nonlinear nonautonomous systems (with linear parts) involving the quadratic time-dependent Lyapunov functions is solved as well as stabilizing a given unstable system with nonlinear control law.

  13. Stabilization of Colloidal Silica Using Small Polyols

    SciTech Connect (OSTI)

    GULLEY, GERALD L.; MARTIN, JAMES E.

    1999-09-07

    We have discovered that small polyols are reasonably effective at stabilizing colloidal silica against aggregation, even under the conditions of high pH and salt concentration. Both quasielastic and elastic light scattering were used to show that these polyols dramatically decrease the aggregation rate of the suspension, changing the growth kinetics from diffusion-limited cluster-cluster aggregation to reaction-limited cluster-cluster aggregation. These polyols maybe useful in the treatment of tank wastes at the Hanford site.

  14. Stability of local quantum dissipative systems

    E-Print Network [OSTI]

    Cubitt, Toby S.; Lucia, Angelo; Michalakis, Spyridon; Perez-Garcia, David

    2015-04-07

    in the engineered Liouvillian itself. Once again, stability against local perturbations – this time for many-body Liouvillians rather than Hamiltonians – is of crucial importance. Indeed, in [53] the authors consider depolarizing noise acting on top of a dissipative... the canonical basis for Hx. Scalar product in Hx will be denoted by ??|??, and rank-one linear maps by |????|. For each finite subset ? ? ? , the associated Hilbert space is given by H? = ? x?? Hx, (1) and the algebra of observables supported on ? is defined...

  15. The Dark Energy Star and Stability analysis

    E-Print Network [OSTI]

    Piyali Bhar; Farook Rahaman

    2015-01-12

    We have proposed a new model of dark energy star consisting of five zones namely, solid core of constant energy density, the thin shell between core and interior, an inhomogeneous interior region with anisotropic pressures, thin shell and the exterior vacuum region. We have discussed various physical properties. The model satisfies all the physical requirements. The stability condition under small linear perturbation has also been discussed.

  16. APCS2009, Nagoya STABILITY OF TENSEGRITY STRUCTURES WITH

    E-Print Network [OSTI]

    Guest, Simon

    APCS2009, Nagoya STABILITY OF TENSEGRITY STRUCTURES WITH DIHEDRAL SYMMETRY Jingyao Zhang1) , Makoto that using symmetry can be of great benefit in an investigation of the stability of tensegrity structures: we are able to find the general super stability condition for a class of structures with the same type

  17. HARETU AND THE STABILITY OF THE SOLAR SYSTEM1

    E-Print Network [OSTI]

    Diacu, Florin

    HARETU AND THE STABILITY OF THE SOLAR SYSTEM1 Florin Diacu2 Pacific Institute for the Mathematical the contributions of Spiru Haretu to the problem of the solar system's stability and show their importance relative and the consequences of Haretu's results. Keywords: stability, solar system, n-body problem. #12;Is the solar system

  18. April 23, 2003 Statistical Learning : CVloo stability is sufficient for

    E-Print Network [OSTI]

    Poggio, Tomaso

    @ai.mit.edu #12;Abstract Solutions of learning problems by Empirical Risk Minimization (ERM) ­ and almost-ERM when- ror. Our second observation is that for bounded loss classes, CVloo stability of ERM is necessary and sufficient for consistency of ERM. We conclude that CVloo stability is the weakest form of stability which

  19. Electrostatic Stabilization of Colloids in Carbon Dioxide: Electrophoresis and Dielectrophoresis

    E-Print Network [OSTI]

    Electrostatic Stabilization of Colloids in Carbon Dioxide: Electrophoresis and Dielectrophoresis in supercritical fluid carbon dioxide (scCO2). Herein we demonstrate that colloids may also be stabilized in CO2 the behavior of steric stabilization in compressed supercritical fluids1-3 including carbon dioxide,4

  20. Generalized Lyapunov Function for Stability Analysis of Interconnected Power Systems

    E-Print Network [OSTI]

    Pota, Himanshu Roy

    Generalized Lyapunov Function for Stability Analysis of Interconnected Power Systems M. A. Mahmud of Lyapunov function is necessary to analyze the stability of a system. This paper presents an idea for formulating generalized Lyapunov function for the stability analysis of interconnected power systems. Lyapunov

  1. Review article Progress on yttria-stabilized zirconia sensors for

    E-Print Network [OSTI]

    Benning, Liane G.

    Review article Progress on yttria-stabilized zirconia sensors for hydrothermal pH measurements S.N., Ulyanov, S.M., 2003. Yttria-Stabilized Zirconia Membrane Electrode, US Patent #6, S17, 694] flow-through, yttria- stabilized zirconia (YSZ) pH sensor has been further tested. The Nernstian behavior and precision

  2. On stability of standing waves of nonlinear Dirac equations

    E-Print Network [OSTI]

    Nabile Boussaid; Scipio Cuccagna

    2012-02-28

    We consider the stability problem for standing waves of nonlinear Dirac models. Under a suitable definition of linear stability, and under some restriction on the spectrum, we prove at the same time orbital and asymptotic stability. We are not able to get the full result proved by Cuccagna for the nonlinear Schr\\"odinger equation, because of the strong indefiniteness of the energy.

  3. RELAP-7 Numerical Stabilization: Entropy Viscosity Method

    SciTech Connect (OSTI)

    R. A. Berry; M. O. Delchini; J. Ragusa

    2014-06-01

    The RELAP-7 code is the next generation nuclear reactor system safety analysis code being developed at the Idaho National Laboratory (INL). The code is based on the INL's modern scientific software development framework, MOOSE (Multi-Physics Object Oriented Simulation Environment). The overall design goal of RELAP-7 is to take advantage of the previous thirty years of advancements in computer architecture, software design, numerical integration methods, and physical models. The end result will be a reactor systems analysis capability that retains and improves upon RELAP5's capability and extends the analysis capability for all reactor system simulation scenarios. RELAP-7 utilizes a single phase and a novel seven-equation two-phase flow models as described in the RELAP-7 Theory Manual (INL/EXT-14-31366). The basic equation systems are hyperbolic, which generally require some type of stabilization (or artificial viscosity) to capture nonlinear discontinuities and to suppress advection-caused oscillations. This report documents one of the available options for this stabilization in RELAP-7 -- a new and novel approach known as the entropy viscosity method. Because the code is an ongoing development effort in which the physical sub models, numerics, and coding are evolving, so too must the specific details of the entropy viscosity stabilization method. Here the fundamentals of the method in their current state are presented.

  4. 308 Building zone I stabilization and confinement

    SciTech Connect (OSTI)

    Metcalf, I.L.; Schwartz, K.E.; Rich, J.W.; Benecke, M.W.; Lanham, G.W.

    1994-08-01

    The 308 Building located on the Hanford Site near Richland, Washington, is currently in transition to shutdown status. After this transition is complete, the facility will be maintained/surveilled and given to the U.S. Department of Energy Office of Facility Transition and Management (EM-60) for utilization, remedial action, or decontamination and decommissioning (D&D). This may require that the facility be maintained in the shutdown status for as long as 30 yrs. To date, all of the special nuclear material (SNM) has been removed, potential fuel supply equipment preserved, surplus materials and equipment excessed, and enclosure cleanup and stabilization completed. A major activity in support of the 308 Building shutdown was the cleanup and stabilization of the enclosures and surface contamination areas. This document discusses the specific designs, processes, and methods used to stabilize and confine the radiological material within the enclosure and exhaust ducts to allow the shutdown of the active support systems. The process and designs employed were effective, yet simple, and maximized the use of current technologies and commercial products.

  5. 308 Building Zone I stabilization and confinement

    SciTech Connect (OSTI)

    Metcalf, I.L.; Schwartz, K.E.; Rich, J.W.; Benecke, M.W.; Rasmussen, D.E.

    1993-10-01

    The 308 Building (Fast Flux Test Facility [FFTF] fuel supply) at the Hanford Site, located in Richland, Washington, is currently in transition to shutdown status. After shutdown, the facility will be maintained/surveilled and turned over to the U.S. Department of Energy (DOE) Office of Facility Transition and Management (EM-60) for utilization, remedial action, or decontamination and decommissioning (D&D). This may require that the facility be maintained in the shutdown mode for up to 30 years. To date, all of the special nuclear material (SNM) has been removed from the facility, potential fuel supply equipment has been preserved, surplus materials and equipment have been excessed, and enclosure cleanup and stabilization has begun. Shutdown planning has been completed, which outlines the major tasks, scope, methodology, and timing for the shutdown activities. A major activity in support of the 308 Building shutdown is the cleanup and stabilization of the enclosures and surface contamination areas. This document identifies the specific designs, processes, and methods to stabilize and confine the radiological material within the enclosures and exhaust ducts to allow shutdown of the active support systems. The designs and steps planned will be effective, are simple, and make maximum use of current technologies and commercial items.

  6. Absence of second stability in ATF

    SciTech Connect (OSTI)

    Dominguez, N.; Lynch, V.E.

    1995-07-01

    Ideal Mercier and ballooning modes for three-dimensional (3-D) equilibria of the Advanced Toroidal Facility (ATF) are studied in detail. These modes are found to introduce instability limits at modest beta values for pressure profiles for which previous results, based on a two-dimensional (2-D) equilibrium approximation, predicted the existence of a second stability region. This absence of second stability is in agreement with an analysis by Cooper et al. who used a simplified model for the ATF plasma boundary. The increased instability is found to result from the 3-D feature of the Pfirsch-Schlueter current. Furthermore, a strong quadrupole field is found to decrease the beta limit of these modes, contrary to the results obtained using the 2-D equilibria. Although direct comparison with measured beta values is not possible owing to the absence of profile data for ATF plasmas, pressure profiles used previously to model ATF data as well as in the 2-D analysis are used to obtain the results. The details of the pressure profiles and the plasma configurations strongly influence the stability limits on average beta which remains below 3%.

  7. Shedding of Vortex Rings from an Oscillating Sphere in Superfluid He-4 below 0.5 K - The Origin of the Turbulent Drag Force

    E-Print Network [OSTI]

    Schoepe, W

    2013-01-01

    The onset of turbulent flow around an oscillating sphere is known to occur at a critical velocity vc ~ sqrt(kappa omega) where kappa is the circulation quantum and omega is the oscillation frequency. However, in a small interval of driving force amplitudes F (or corresponding velocity amplitudes of few percent above vc) the turbulent flow is found to be unstable. The flow pattern switches intermittently between potential flow and turbulence. The lifetimes of the turbulent phases have an exponential distribution and the mean lifetimes tau grow very rapidly with increasing driving force, namely as tau(F) ~ exp [(F/F1)^2]. In this work this experimental result is analyzed in more detail than before, in particular the force F1 is identified. As a result, the turbulent drag force F(v) ~ (v^2 - vc^2) can be ascribed quantitatively to the shedding of vortex rings having the size of the sphere. Moreover, we can infer the average number of vortex rings that are shed per half-period at any given velocity v on the turbu...

  8. Spatially evolving vortex-gas turbulent free shear layers: Part 1. Effect of velocity ratio, and upstream and downstream conditions on spread-rate

    E-Print Network [OSTI]

    Suryanarayanan, Saikishan

    2015-01-01

    The relevance of the vortex-gas model to the large scale dynamics of temporally evolving turbulent free shear layers in an inviscid incompressible fluid has recently been established by extensive numerical simulations (Suryanarayanan et al, Phys. Rev. E 89, 013009, 2014). Here, the effects of the velocity ratio across a spatially evolving 2D free shear layer are investigated by vortex-gas simulations, using a computational model based on Basu et al (1992, 1995), but with a crucial improvement that ensures conservation of global circulation. These are carried out for a range of values of the velocity ratio parameter $\\lambda= (U_1-U_2)/(U_1+U_2)$, where $U_1$ and $U_2$ ($< U_1$) are respective velocities across the layer. The simulations show that the conditions imposed at the beginning of the free shear layer and at the exit to the domain can affect the flow evolution in their respective neighborhoods, the latter being particularly strong as $\\lambda \\rightarrow 1$. In between the two neighborhoods is a re...

  9. VOLUME 83, NUMBER 8 P H Y S I C A L R E V I E W L E T T E R S 23 AUGUST 1999 Flow Induced Organization and Memory of a Vortex Lattice

    E-Print Network [OSTI]

    Andrei, Eva Y.

    in response to a driving current in 2H-NbSe2 crystals. By using fast transport measurements we find exhibits a long-term memory: if the current is turned off the vortices freeze in place remembering) [15] and transport measurements [5], it is inversely proportional to the size of an ordered vortex

  10. Criterion of stability of the superconducting state

    E-Print Network [OSTI]

    Iogann Tolbatov

    2009-10-23

    In this paper, we propose to draw attention to the stability criterion of the superconductor current state. We use for this purpose the rough systems mathematical apparatus allowing us to relate the desired criterion with the dielectric permittivity of the matter and to identify the type of all possible phonons trajectories in its superconducting state. The state of superconductivity in the matter can be explained only by the phonons behavior peculiarity. And on the basis of the above-mentioned assumption, the corresponding mathematical model is constructed.

  11. Linear Stability Analysis of Dynamical Quadratic Gravity

    E-Print Network [OSTI]

    Dimitry Ayzenberg; Kent Yagi; Nicolas Yunes

    2014-03-18

    We perform a linear stability analysis of dynamical, quadratic gravity in the high-frequency, geometric optics approximation. This analysis is based on a study of gravitational and scalar modes propagating on spherically-symmetric and axially-symmetric, vacuum solutions of the theory. We find dispersion relations that do no lead to exponential growth of the propagating modes, suggesting the theory is linearly stable on these backgrounds. The modes are found to propagate at subluminal and superluminal speeds, depending on the propagating modes' direction relative to the background geometry, just as in dynamical Chern-Simons gravity.

  12. Thermal stability of radiant black holes

    E-Print Network [OSTI]

    Parthasarathi Majumdar

    2006-04-06

    Beginning with a brief sketch of the derivation of Hawking's theorem of horizon area increase, based on the Raychaudhuri equation, we go on to discuss the issue as to whether generic black holes, undergoing Hawking radiation, can ever remain in stable thermal equilibrium with that radiation. We derive a universal criterion for such a stability, which relates the black hole mass and microcanonical entropy, both of which are well-defined within the context of the Isolated Horizon, and in principle calculable within Loop Quantum Gravity. The criterion is argued to hold even when thermal fluctuations of electric charge are considered, within a {\\it grand} canonical ensemble.

  13. Oxygen stabilized zirconium-vanadium-iron alloy

    DOE Patents [OSTI]

    Mendelsohn, Marshall H. (Woodridge, IL); Gruen, Dieter M. (Downers Grove, IL)

    1982-01-01

    An oxygen stabilized intermetallic compound having the formula (Zr.sub.1-x Ti.sub.x).sub.2-u (V.sub.1-y Fe.sub.y)O.sub.z where x=0.0 to 0.9, y=0.01 to 0.9, z=0.25 to 0.5 and u=0 to 1. The compound is capable of reversibly sorbing hydrogen at temperatures from -196.degree. C. to 200.degree. C. at pressures down to 10.sup.-6 torr. The compound is suitable for use as a hydrogen getter in low pressure, high temperature applications such as magnetic confinement fusion devices.

  14. Radiation stability of graphene under extreme conditions

    SciTech Connect (OSTI)

    Kumar, Sunil, E-mail: kumar.sunil092@gmail.com; Tripathi, Ambuj; Khan, Saif A.; Pannu, Compesh; Avasthi, Devesh K. [Materials Science Group, Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India)

    2014-09-29

    In this letter, we report radiation stability of graphene under extreme condition of high energy density generated by 150?MeV Au ion irradiation. The experiment reveals that graphene is radiation resistant for irradiation at 10{sup 14?}ions/cm{sup 2} of 150?MeV Au ions. It is significant to note that annealing effects are observed at lower fluences whereas defect production occurs at higher fluences but significant crystallinity is retained. Our results demonstrate applicability of graphene based devices in radiation environment and space applications.

  15. Ceramic membranes with enhanced thermal stability

    DOE Patents [OSTI]

    Anderson, Marc A. (Madison, WI); Xu, Qunyin (Plainsboro, NJ); Bischoff, Brian L. (Madison, WI)

    1993-01-01

    A method of creating a ceramic membrane with enhanced thermal stability is disclosed. The method involves combining quantities of a first metal alkoxide with a second metal, the quantities selected to give a preselected metal ratio in the resultant membrane. A limited amount of water and acid is added to the combination and stirred until a colloidal suspension is formed. The colloid is dried to a gel, and the gel is fired at a temperature greater than approximately 400.degree. C. The porosity and surface area of ceramic membranes formed by this method are not adversely affected by this high temperature firing.

  16. Shear thickening in Electrically Stabilized Colloidal Suspensions

    E-Print Network [OSTI]

    Joachim Kaldasch; Bernhard Senge; Jozua Laven

    2011-07-25

    A theory is presented for the onset of shear thickening in colloidal suspensions of particles, stabilized by an electrostatic repulsion. Based on an activation model a critical shear stress can be derived for the onset of shear thickening in dense suspensions for a constant potential and a constant charge approach of the spheres. Unlike previous models the total interaction potential is taken into account (sum of attraction and repulsion). The critical shear stress is related to the maximum of the total interaction potential scaled by the free volume per particle. A comparison with experimental investigations shows the applicability of the theory.

  17. Shear Thickening in Polymer Stabilized Colloidal Suspensions

    E-Print Network [OSTI]

    Joachim Kaldasch; Bernhard Senge

    2012-07-11

    This paper adopts a previously developed activation model of shear thickening, published by the authors, to sterically stabilized colloidal suspensions. When particles arranged along the compression axis of a sheared suspension, they may overcome the repulsive interaction and form hydroclusters associated with shear thickening. Taking advantage of the total interaction potential of polymeric brush coating and van der Waals attraction, the applicability of the activation model is shown within the validity range of a continuum theory. For the comparison with an extensive experimental investigation, where some parameters are not available, the onset of shear thickening can be predicted with realistic assumptions of the model parameters.

  18. Stability of Two-Dimensional Soft Quasicrystals

    E-Print Network [OSTI]

    Kai Jiang; Jiajun Tong; Pingwen Zhang; An-Chang Shi

    2015-05-26

    The relative stability of two-dimensional soft quasicrystals is examined using a recently developed projection method which provides a unified numerical framework to compute the free energy of periodic crystal and quasicrystals. Accurate free energies of numerous ordered phases, including dodecagonal, decagonal and octagonal quasicrystals, are obtained for a simple model, i.e. the Lifshitz-Petrich free energy functional, of soft quasicrystals with two length-scales. The availability of the free energy allows us to construct phase diagrams of the system, demonstrating that, for the Lifshitz-Petrich model, the dodecagonal and decagonal quasicrystals can become stable phases, whereas the octagonal quasicrystal stays as a metastable phase.

  19. Sensitivity approximation for robust stability and tracking 

    E-Print Network [OSTI]

    McLean, Chris Steven

    1984-01-01

    ) Norman W. Na gle (Member) Don R. Halverson (Member) William B. Jones (Head of Department) May 1984 1n Abstract Sensitivity Approximation for Robust Stability and Tracking. (May 1984) Chris Steven McLean, B. S, , Louisiana Tech University... indispensable to the completion of this thesis. I would like to thank Dr. S. P. Bhattacharyya for introducing me to the wonders of automatic control. I also would like to thank Dr. D. R. Halverson and Dr. N. W. Naugle for serving on my committee, Dr. John...

  20. Stellar stability in brane-worlds revisited

    E-Print Network [OSTI]

    Miguel A. García-Aspeitia; L. Arturo Ureña-López

    2014-12-28

    We consider here the general conditions for the stability of brane stars that obey a so called a "minimal setup": the nonlocal anisotropic stress and energy flux are everywhere absent, and the only permitted Weyl correction is the interior solution of the nonlocal energy density. Along with a series of simple conditions, we show that the Germani-Maartens solution with a constant density sets up the upper bound for the compactness of that particular class of brane stars. The general demonstration is based upon the properties of the interior solutions of the stars, although we also show that the minimal setup implies a Schwarzschild exterior.