Sample records for wave power density

  1. Effect of electron density profile on power absorption of high frequency electromagnetic waves in plasma

    SciTech Connect (OSTI)

    Xi Yanbin; Liu Yue [MOE Key Laboratory of Materials Modification by Laser, Electron, and Ion Beams, School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2012-07-15T23:59:59.000Z

    Considering different typical electron density profiles, a multi slab approximation model is built up to study the power absorption of broadband (0.75-30 GHz) electromagnetic waves in a partially ionized nonuniform magnetized plasma layer. Based on the model, the power absorption spectra for six cases are numerically calculated and analyzed. It is shown that the absorption strongly depends on the electron density fluctuant profile, the background electron number density, and the collision frequency. A potential optimum profile is also analyzed and studied with some particular parameters.

  2. Bayesian semiparametric power spectral density estimation in gravitational wave data analysis

    E-Print Network [OSTI]

    Edwards, Matthew C; Christensen, Nelson

    2015-01-01T23:59:59.000Z

    The standard noise model in gravitational wave (GW) data analysis assumes detector noise is stationary and Gaussian distributed, with a known power spectral density (PSD) that is usually estimated using clean off-source data. Real GW data often depart from these assumptions, and misspecified parametric models of the PSD could result in misleading inferences. We propose a Bayesian semiparametric approach to improve this. We use a nonparametric Bernstein polynomial prior on the PSD, with weights attained via a Dirichlet process distribution, and update this using the Whittle likelihood. Posterior samples are obtained using a Metropolis-within-Gibbs sampler. We simultaneously estimate the reconstruction parameters of a rotating core collapse supernova GW burst that has been embedded in simulated Advanced LIGO noise. We also discuss an approach to deal with non-stationary data by breaking longer data streams into smaller and locally stationary components.

  3. Shear-horizontal surface acoustic wave phononic device with high density filling material for ultra-low power sensing applications

    SciTech Connect (OSTI)

    Richardson, M.; Bhethanabotla, V. R., E-mail: bhethana@usf.edu [Department of Chemical and Biomedical Engineering, University of South Florida, Tampa, Florida 33620 (United States); Sankaranarayanan, S. K. R. S. [Center for Nanoscale Materials, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

    2014-06-23T23:59:59.000Z

    Finite element simulations of a phononic shear-horizontal surface acoustic wave (SAW) sensor based on ST 90°-X Quartz reveal a dramatic reduction in power consumption. The phononic sensor is realized by artificially structuring the delay path to form an acoustic meta-material comprised of a periodic microcavity array incorporating high-density materials such as tantalum or tungsten. Constructive interference of the scattered and secondary reflected waves at every microcavity interface leads to acoustic energy confinement in the high-density regions translating into reduced power loss. Tantalum filled cavities show the best performance while tungsten inclusions create a phononic bandgap. Based on our simulation results, SAW devices with tantalum filled microcavities were fabricated and shown to significantly decrease insertion loss. Our findings offer encouraging prospects for designing low power, highly sensitive portable biosensors.

  4. Minimization of Fractional Power Densities

    E-Print Network [OSTI]

    Minimization of Fractional Power Densities. Robert Hardt, Rice University. Abstract: A k dimensional rectifiable current is given by an oriented k dimensional

  5. Inverse diffusion from knowledge of power densities

    E-Print Network [OSTI]

    Bal, Guillaume; Monard, Francois; Triki, Faouzi

    2011-01-01T23:59:59.000Z

    This paper concerns the reconstruction of a diffusion coefficient in an elliptic equation from knowledge of several power densities. The power density is the product of the diffusion coefficient with the square of the modulus of the gradient of the elliptic solution. The derivation of such internal functionals comes from perturbing the medium of interest by acoustic (plane) waves, which results in small changes in the diffusion coefficient. After appropriate asymptotic expansions and (Fourier) transformation, this allow us to construct the power density of the equation point-wise inside the domain. Such a setting finds applications in ultrasound modulated electrical impedance tomography and ultrasound modulated optical tomography. We show that the diffusion coefficient can be uniquely and stably reconstructed from knowledge of a sufficient large number of power densities. Explicit expressions for the reconstruction of the diffusion coefficient are also provided. Such results hold for a large class of boundary...

  6. Secondary dust density waves excited by nonlinear dust acoustic waves

    SciTech Connect (OSTI)

    Heinrich, J. R.; Kim, S.-H.; Meyer, J. K.; Merlino, R. L. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States); Rosenberg, M. [Department of Electrical and Computer Engineering, University of California, San Diego, California 92093 (United States)

    2012-08-15T23:59:59.000Z

    Secondary dust density waves were observed in conjunction with high amplitude (n{sub d}/n{sub d0}>2) dust acoustic waves (DAW) that were spontaneously excited in a dc glow discharge dusty plasma in the moderately coupled, {Gamma}{approx}1, state. The high amplitude dust acoustic waves produced large dust particle oscillations, displacements, and trapping. Secondary dust density waves were excited in the wave troughs of the high amplitude DAWs. The waveforms, amplitudes, wavelengths, and wave speeds of the primary DAWs and the secondary waves were measured. A dust-dust streaming instability is discussed as a possible mechanism for the production of the secondary waves.

  7. Global coherence of dust density waves

    SciTech Connect (OSTI)

    Killer, Carsten; Melzer, André [Institut für Physik, Ernst-Moritz-Arndt-Universität Greifswald, 17489 Greifswald (Germany)

    2014-06-15T23:59:59.000Z

    The coherence of self-excited three-dimensional dust density waves has been experimentally investigated by comparing global and local wave properties. For that purpose, three-dimensional dust clouds have been confined in a radio frequency plasma with thermophoretic levitation. Global wave properties have been measured from the line-of-sight integrated dust density obtained from homogenous light extinction measurements. Local wave properties have been obtained from thin, two-dimensional illuminated laser slices of the cloud. By correlating the simultaneous global and local wave properties, the spatial coherence of the waves has been determined. We find that linear waves with small amplitudes tend to be fragmented, featuring an incoherent wave field. Strongly non-linear waves with large amplitudes, however, feature a strong spatial coherence throughout the dust cloud, indicating a high level of synchronization.

  8. Using Radio Waves to Control Fusion Plasma Density

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

    Using Radio Waves to Control Fusion Plasma Density Using Radio Waves to Control Fusion Plasma Density Simulations Run at NERSC Support Fusion Experiments at MIT, General Atomics...

  9. Oblique interactions of dust density waves

    SciTech Connect (OSTI)

    Wang, Zhelchui [Los Alamos National Laboratory; Li, Yang - Fang [MAX-PLANCK INSTITUTE; Hou, Lujing [MAX-PLANCK INSTITUTE; Jiang, Ke [MAX-PLANCK INSTITUTE; Wu, De - Jin [CHINA; Thomas, Hubertus M [MAX-PLANCK INSTITUTE; Morfill, Gregor E [MAX-PLANCK INSTITUTE

    2010-01-01T23:59:59.000Z

    Self-excited dust density waves (DDWs) are studied in a striped electrode device. In addition to the usual perpendicularly (with respect to the electrode) propagating DDWs, which have been frequently observed in dusty plasma experiments on the ground, a low-frequency oblique mode is also observed. This low-frequency oblique DDW has a frequency much lower than the dust plasma frequency and its spontaneous excitation is observed even with a very low dust density. It is found that the low-frequency oblique mode can exist either separately or together with the usual perpendicular mode. In the latter case, a new mode arises as a result of the interactions between the perpendicular and the oblique modes. The experiments show that these three modes satisfy the wave coupling conditions in both the frequencies and the wave-vectors.

  10. Density waves in the Calogero model - revisited

    SciTech Connect (OSTI)

    Bardek, V. [Rudjer Boskovic Institute, Bijenicka c.54, HR-10002 Zagreb (Croatia)], E-mail: bardek@irb.hr; Feinberg, J. [Department of Physics, University of Haifa at Oranim, Tivon 36006 (Israel); Department of Physics, Technion-Israel Inst. of Technology, Haifa 32000 (Israel); KITP, University of California, Santa Barbara, CA 93106-4030 (United States)], E-mail: joshua@physics.technion.ac.il; Meljanac, S. [Rudjer Boskovic Institute, Bijenicka c.54, HR-10002 Zagreb (Croatia)], E-mail: meljanac@irb.hr

    2010-03-15T23:59:59.000Z

    The Calogero model bears, in the continuum limit, collective excitations in the form of density waves and solitary modulations of the density of particles. This sector of the spectrum of the model was investigated, mostly within the framework of collective-field theory, by several authors, over the past 15 years or so. In this work we shall concentrate on periodic solutions of the collective BPS-equation (also known as 'finite amplitude density waves'), as well as on periodic solutions of the full static variational equations which vanish periodically (also known as 'large amplitude density waves'). While these solutions are not new, we feel that our analysis and presentation add to the existing literature, as we explain in the text. In addition, we show that these solutions also occur in a certain two-family generalization of the Calogero model, at special points in parameter space. A compendium of useful identities associated with Hilbert transforms, including our own proofs of these identities, appears in Appendix A. In Appendix B we also elucidate in the present paper some fine points having to do with manipulating Hilbert-transforms, which appear ubiquitously in the collective field formalism. Finally, in order to make this paper self-contained, we briefly summarize in Appendix C basic facts about the collective field formulation of the Calogero model.

  11. Tracing spiral density waves in M81

    E-Print Network [OSTI]

    S. Kendall; R. C. Kennicutt; C. Clarke; M. D. Thornley

    2008-04-15T23:59:59.000Z

    We use SPITZER IRAC 3.6 and 4.5micron near infrared data from the Spitzer Infrared Nearby Galaxies Survey (SINGS), optical B, V and I and 2MASS Ks band data to produce mass surface density maps of M81. The IRAC 3.6 and 4.5micron data, whilst dominated by emission from old stellar populations, is corrected for small-scale contamination by young stars and PAH emission. The I band data are used to produce a mass surface density map by a B-V colour-correction, following the method of Bell and de Jong. We fit a bulge and exponential disc to each mass map, and subtract these components to reveal the non-axisymmetric mass surface density. From the residual mass maps we are able to extract the amplitude and phase of the density wave, using azimuthal profiles. The response of the gas is observed via dust emission in the 8micron IRAC band, allowing a comparison between the phase of the stellar density wave and gas shock. The relationship between this angular offset and radius suggests that the spiral structure is reasonably long lived and allows the position of corotation to be determined.

  12. Energy-momentum Density of Gravitational Waves

    E-Print Network [OSTI]

    Amir M. Abbassi; Saeed Mirshekari

    2014-11-29T23:59:59.000Z

    In this paper, we elaborate the problem of energy-momentum in general relativity by energy-momentum prescriptions theory. Our aim is to calculate energy and momentum densities for the general form of gravitational waves. In this connection, we have extended the previous works by using the prescriptions of Bergmann and Tolman. It is shown that they are finite and reasonable. In addition, using Tolman prescription, exactly, leads to same results that have been obtained by Einstein and Papapetrou prescriptions.

  13. Power recycling for an interferometric gravitational wave

    E-Print Network [OSTI]

    Ejiri, Shinji

    THESIS Power recycling for an interferometric gravitational wave detector Masaki Ando Department . . . . . . . . . . . . . . 48 3.3 Power recycling . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 3.3.1 Principle of power recycling . . . . . . . . . . . . . . . . . 50 3.3.2 Recycling cavity

  14. Considering Air Density in Wind Power Production

    E-Print Network [OSTI]

    Zénó Farkas

    2011-03-11T23:59:59.000Z

    In the wind power production calculations the air density is usually considered as constant in time. Using the CIPM-2007 equation for the density of moist air as a function of air temperature, air pressure and relative humidity, we show that it is worth taking the variation of the air density into account, because higher accuracy can be obtained in the calculation of the power production for little effort.

  15. Considering Air Density in Wind Power Production

    E-Print Network [OSTI]

    Farkas, Zénó

    2011-01-01T23:59:59.000Z

    In the wind power production calculations the air density is usually considered as constant in time. Using the CIPM-2007 equation for the density of moist air as a function of air temperature, air pressure and relative humidity, we show that it is worth taking the variation of the air density into account, because higher accuracy can be obtained in the calculation of the power production for little effort.

  16. Wave Power Demonstration Project at Reedsport, Oregon

    SciTech Connect (OSTI)

    Mekhiche, Mike [Principal Investigator] [Principal Investigator; Downie, Bruce [Project Manager] [Project Manager

    2013-10-21T23:59:59.000Z

    Ocean wave power can be a significant source of large?scale, renewable energy for the US electrical grid. The Electrical Power Research Institute (EPRI) conservatively estimated that 20% of all US electricity could be generated by wave energy. Ocean Power Technologies, Inc. (OPT), with funding from private sources and the US Navy, developed the PowerBuoy? to generate renewable energy from the readily available power in ocean waves. OPT's PowerBuoy converts the energy in ocean waves to electricity using the rise and fall of waves to move the buoy up and down (mechanical stroking) which drives an electric generator. This electricity is then conditioned and transmitted ashore as high?voltage power via underwater cable. OPT's wave power generation system includes sophisticated techniques to automatically tune the system for efficient conversion of random wave energy into low cost green electricity, for disconnecting the system in large waves for hardware safety and protection, and for automatically restoring operation when wave conditions normalize. As the first utility scale wave power project in the US, the Wave Power Demonstration Project at Reedsport, OR, will consist of 10 PowerBuoys located 2.5 miles off the coast. This U.S. Department of Energy Grant funding along with funding from PNGC Power, an Oregon?based electric power cooperative, was utilized for the design completion, fabrication, assembly and factory testing of the first PowerBuoy for the Reedsport project. At this time, the design and fabrication of this first PowerBuoy and factory testing of the power take?off subsystem are complete; additionally the power take?off subsystem has been successfully integrated into the spar.

  17. Nonlocal theory of electromagnetic wave decay into two electromagnetic waves in a rippled density plasma channel

    SciTech Connect (OSTI)

    Sati, Priti; Tripathi, V. K. [Indian Institute of Technology, Hauz Khas, Delhi 110054 (India)

    2012-12-15T23:59:59.000Z

    Parametric decay of a large amplitude electromagnetic wave into two electromagnetic modes in a rippled density plasma channel is investigated. The channel is taken to possess step density profile besides a density ripple of axial wave vector. The density ripple accounts for the momentum mismatch between the interacting waves and facilitates nonlinear coupling. For a given pump wave frequency, the requisite ripple wave number varies only a little w.r.t. the frequency of the low frequency decay wave. The radial localization of electromagnetic wave reduces the growth rate of the parametric instability. The growth rate decreases with the frequency of low frequency electromagnetic wave.

  18. Competition between superconductivity and spin density wave

    E-Print Network [OSTI]

    Tian De Cao

    2012-08-25T23:59:59.000Z

    The Hubbard model has been investigated widely by many authors, while this work may be new in two aspects. One, we focus on the possible effects of the positions of the gaps associated with the pairing and the spin density wave. Two, we suggest that the models with different parameters are appropriate for different materials (or a material in different doped regions). This will lead to some new insights into the high temperature superconductors. It is shown that the SDW can appear at some temperature region when the on-site Coulomb interaction is larger, while the SC requires a decreased U at a lower temperature. This can qualitatively explain the relationship between superconducting and pseudogap states of Cu-based superconductors in underdoped and optimally doped regions. The superinsulator is also discussed.

  19. A restoration model of distorted electron density in wave-cutoff probe measurement

    SciTech Connect (OSTI)

    Jun, Hyun-Su, E-mail: mtsconst@kaist.ac.kr; Lee, Yun-Seong [Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of)] [Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon 305-701 (Korea, Republic of)

    2014-02-15T23:59:59.000Z

    This study investigates the problem of electron density distortion and how the density can be restored in a wave-cutoff probe. Despite recent plasma diagnostics research using a wave-cutoff probe, the problem of electron density distortion caused by plasma conditions has not been resolved. Experimental results indicate that electron density measured using the wave-cutoff method is highly susceptible to variations in the probe tip gap. This electron density distortion is caused by the bulk plasma disturbance between probe tips, and it must be removed for calculating the absolute electron density. To do this, a detailed analytic model was developed using the power balance equation near probe tips. This model demonstrates the characteristics of plasma distortion in wave-cutoff probe measurement and successfully restored the absolute value of electron density with varying probe tip gaps.

  20. Ducted kinetic Alfven waves in plasma with steep density gradients

    SciTech Connect (OSTI)

    Houshmandyar, Saeid [Solar Observatory Department, Prairie View A and M University, Prairie View, Texas 77446 (United States); Department of Physics, West Virginia University, Morgantown, West Virginia 26506-6315 (United States); Scime, Earl E. [Department of Physics, West Virginia University, Morgantown, West Virginia 26506-6315 (United States)

    2011-11-15T23:59:59.000Z

    Given their high plasma density (n {approx} 10{sup 13} cm{sup -3}), it is theoretically possible to excite Alfven waves in a conventional, moderate length (L {approx} 2 m) helicon plasma source. However, helicon plasmas are decidedly inhomogeneous, having a steep radial density gradient, and typically have a significant background neutral pressure. The inhomogeneity introduces regions of kinetic and inertial Alfven wave propagation. Ion-neutral and electron-neutral collisions alter the Alfven wave dispersion characteristics. Here, we present the measurements of propagating kinetic Alfven waves in helium helicon plasma. The measured wave dispersion is well fit with a kinetic model that includes the effects of ion-neutral damping and that assumes the high density plasma core defines the radial extent of the wave propagation region. The measured wave amplitude versus plasma radius is consistent with the pile up of wave magnetic energy at the boundary between the kinetic and inertial regime regions.

  1. High power density supercapacitors using locally aligned carbon nanotube electrodes

    E-Print Network [OSTI]

    Du, C S; Yeh, J; Pan, Ning

    2005-01-01T23:59:59.000Z

    4484/16/4/003 High power density supercapacitors usingproduced very high speci?c power density of about 30 kW kg ?manufacturing of high power density supercapacitors and

  2. High-power-density spot cooling using bulk thermoelectrics

    E-Print Network [OSTI]

    Zhang, Y; Shakouri, A; Zeng, G H

    2004-01-01T23:59:59.000Z

    model, the cooling power densities of the devices can alsothe cooling power densities 2–24 times. Experimentally, the14 4 OCTOBER 2004 High-power-density spot cooling using bulk

  3. High power density solid oxide fuel cells

    SciTech Connect (OSTI)

    Pham, Ai Quoc; Glass, Robert S.

    2004-10-12T23:59:59.000Z

    A method for producing ultra-high power density solid oxide fuel cells (SOFCs). The method involves the formation of a multilayer structure cells wherein a buffer layer of doped-ceria is deposited intermediate a zirconia electrolyte and a cobalt iron based electrode using a colloidal spray deposition (CSD) technique. For example, a cobalt iron based cathode composed of (La,Sr)(Co,Fe)O (LSCF) may be deposited on a zirconia electrolyte via a buffer layer of doped-ceria deposited by the CSD technique. The thus formed SOFC have a power density of 1400 mW/cm.sup.2 at 600.degree. C. and 900 mW/cm.sup.2 at 700.degree. C. which constitutes a 2-3 times increased in power density over conventionally produced SOFCs.

  4. High power density supercapacitors using locally aligned carbon nanotube electrodes

    E-Print Network [OSTI]

    Du, C S; Yeh, J; Pan, Ning

    2005-01-01T23:59:59.000Z

    High power density supercapacitors using locally alignedof high power density supercapacitors and other similarcells [6], and for supercapacitors [7–18]. As unique energy

  5. Methods to enhance blanket power density

    SciTech Connect (OSTI)

    Hsu, P.Y.; Miller, L.G.; Bohn, T.S.; Deis, G.A.; Longhurst, G.R.; Masson, L.S.; Wessol, D.E.; Abdou, M.A.

    1982-06-01T23:59:59.000Z

    The overall objective of this task is to investigate the extent to which the power density in the FED/INTOR breeder blanket test modules can be enhanced by artificial means. Assuming a viable approach can be developed, it will allow advanced reactor blanket modules to be tested on FED/INTOR under representative conditions.

  6. High power density thermophotovoltaic energy conversion

    SciTech Connect (OSTI)

    Noreen, D.L. [R& D Technologies, Inc., Hoboken, New Jersey 07030 (United States); Du, H. [Department of Materials Science and Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030 (United States)

    1995-01-05T23:59:59.000Z

    R&D Technologies is developing thermophotovoltaic (TPV) technology based on the use of porous/fibrous ceramic broadband-type emitter designs that utilize recuperative or regenerative techniques to improve thermal efficiency and power density. This paper describes preliminary estimates of what will be required to accomplish sufficient power density to develop a practical, commercially-viable TPV generator. It addresses the needs for improved, thermal shock-resistant, long-life porous/fibrous ceramic emitters and provides information on the photocell technology required to achieve acceptable power density in broadband-type (with selective filter) TPV systems. TPV combustors/systems operating at a temperature of 1500 {degree}C with a broadband-type emitter is proposed as a viable starting point for cost-effective TPV conversion. Based on current projections for photocell cost, system power densities of 7.5--10 watts per square centimeter of emitter area will be required for TPV to become a commercially viable technology. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

  7. Kinematic Density Waves in Accretion Disks

    E-Print Network [OSTI]

    Svetlin Tassev; Edmund Bertschinger

    2008-10-14T23:59:59.000Z

    When thin accretion disks around black holes are perturbed, the main restoring force is gravity. If gas pressure, magnetic stresses, and radiation pressure are neglected, the disk remains thin as long as orbits do not intersect. Intersections would result in pressure forces which limit the growth of perturbations. We find that a discrete set of perturbations is possible for which orbits remain non-intersecting for arbitrarily long times. These modes define a discrete set of frequencies. We classify all long-lived perturbations for arbitrary potentials and show how their mode frequencies are related to pattern speeds computed from the azimuthal and epicyclic frequencies. We show that modes are concentrated near radii where the pattern speed has vanishing radial derivative. We explore these modes around Kerr black holes as a possible explanation for the high-frequency quasi-periodic oscillations of black hole binaries such as GRO J1655-40. The long-lived modes are shown to coincide with diskoseismic waves in the limit of small sound speed. While the waves have long lifetime, they have the wrong frequencies to explain the pairs of high-frequency quasi-periodic oscillations observed in black hole binaries.

  8. Innovative fuel designs for high power density pressurized water reactor

    E-Print Network [OSTI]

    Feng, Dandong, Ph. D. Massachusetts Institute of Technology

    2006-01-01T23:59:59.000Z

    One of the ways to lower the cost of nuclear energy is to increase the power density of the reactor core. Features of fuel design that enhance the potential for high power density are derived based on characteristics of ...

  9. Design of annular fuel for high power density BWRs

    E-Print Network [OSTI]

    Morra, Paolo

    2005-01-01T23:59:59.000Z

    Enabling high power density in the core of Boiling Water Reactors (BWRs) is economically profitable for existing or new reactors. In this work, we examine the potential for increasing the power density in BWR plants by ...

  10. Density waves in the shearing sheet III. Disc heating

    E-Print Network [OSTI]

    B. Fuchs

    2001-04-25T23:59:59.000Z

    The problem of dynamical heating of galactic discs by spiral density waves is discussed using the shearing sheet model. The secular evolution of the disc is described quantitatively by a diffusion equation for the distribution function of stars in the space spanned by integrals of motion of the stars, in particular the radial action integral and an integral related to the angular momentum. Specifically, disc heating by a succession of transient, `swing amplified' density waves is studied. It is shown that such density waves lead predominantly to diffusion of stars in radial action space. The stochastical changes of angular momenta of the stars and the corresponding stochastic changes of the guiding centre radii of the stellar orbits induced by this process are much smaller.

  11. Density matrix renormalization group and wave function factorization for nuclei

    E-Print Network [OSTI]

    T. Papenbrock; D. J. Dean

    2005-07-15T23:59:59.000Z

    We employ the density matrix renormalization group (DMRG) and the wave function factorization method for the numerical solution of large scale nuclear structure problems. The DMRG exhibits an improved convergence for problems with realistic interactions due to the implementation of the finite algorithm. The wave function factorization of fpg-shell nuclei yields rapidly converging approximations that are at the present frontier for large-scale shell model calculations.

  12. Inverse diffusion from knowledge of power densities Guillaume Bal

    E-Print Network [OSTI]

    Bal, Guillaume

    asymptotic expansions and (Fourier) transformation, this allow us to construct the power density) provides access to the power density H(x) = (x)|u|2 (x) for all x inside the domain of interestInverse diffusion from knowledge of power densities Guillaume Bal , Eric Bonnetier , Fran

  13. Metal-insulator Transition by Holographic Charge Density Waves

    E-Print Network [OSTI]

    Yi Ling; Chao Niu; Jianpin Wu; Zhuoyu Xian; Hongbao Zhang

    2014-08-06T23:59:59.000Z

    We construct a gravity dual for charge density waves (CDW) in which the translational symmetry along one spatial direction is spontaneously broken. Our linear perturbation calculation on the gravity side produces the frequency dependence of the optical conductivity, which exhibits the two familiar features of charge density waves, namely the pinned collective mode and gapped single-particle excitation. These two features indicate that our gravity dual also provides a new mechanism to implement the metal to insulator phase transition by CDW, which is further supported by the fact that d.c. conductivity decreases with the decreased temperature below the critical temperature.

  14. Revamped Simulation Tool to Power Up Wave Energy Development...

    Energy Savers [EERE]

    Revamped Simulation Tool to Power Up Wave Energy Development Revamped Simulation Tool to Power Up Wave Energy Development May 21, 2015 - 2:40pm Addthis Revamped Simulation Tool to...

  15. Columbia Power Technologies, Inc. Deploys its Direct Drive Wave...

    Office of Environmental Management (EM)

    Columbia Power Technologies, Inc. Deploys its Direct Drive Wave Energy Buoy Columbia Power Technologies, Inc. Deploys its Direct Drive Wave Energy Buoy April 9, 2013 - 12:00am...

  16. Highly Resolved Self-Excited Density Waves in a Complex Plasma

    SciTech Connect (OSTI)

    Schwabe, M.; Rubin-Zuzic, M.; Zhdanov, S.; Thomas, H. M.; Morfill, G. E. [Max-Planck-Institut fuer extraterrestrische Physik, D-85740 Garching (Germany)

    2007-08-31T23:59:59.000Z

    Experimental results on self-excited density waves in a complex plasma are presented. An argon plasma is produced in a capacitively coupled rf discharge at a low power and gas pressure. A cloud of microparticles is subjected to effective gravity in the range of 1-4 g by thermophoresis. The cloud is stretched horizontally (width/height {approx_equal}45 mm/8 mm). The critical pressure for the onset of the waves increases with the temperature gradient. The waves are propagating in the direction of the ion drift. The wave frequency, phase velocity, and wavelength are measured, and particle migrations affected by the waves are analyzed at a time scale of 1 ms/frame and a subpixel space resolution.

  17. Density inhomogeneity driven electrostatic shock waves in planetary rings

    SciTech Connect (OSTI)

    Masood, W.; Siddiq, M. [Theoretical Plasma Physics Division (TPPD), PINSTECH, P. O. Nilore, Islamabad 44000 (Pakistan); National Center for Physics (NCP), Islamabad 44000 (Pakistan); Rizvi, H.; Haque, Q. [Theoretical Plasma Physics Division (TPPD), PINSTECH, P. O. Nilore, Islamabad 44000 (Pakistan); Hasnain, H. [NILOP, P. O. Nilore, Islamabad 44000 (Pakistan); PIEAS, P. O. Nilore, Islamabad 44000 (Pakistan)

    2011-05-15T23:59:59.000Z

    Dust inertia and background density driven dust drift shock waves are theoretically studied in a rotating planetary environment and are subsequently applied to the planetary rings where the collisional effects are pronounced. It has been found that the system under consideration admits significant shock formation if the collision frequency is of the order of or less than the rotational frequency of the Saturn's rings.

  18. PSD computations using Welch's method. [Power Spectral Density (PSD)

    SciTech Connect (OSTI)

    Solomon, Jr, O M

    1991-12-01T23:59:59.000Z

    This report describes Welch's method for computing Power Spectral Densities (PSDs). We first describe the bandpass filter method which uses filtering, squaring, and averaging operations to estimate a PSD. Second, we delineate the relationship of Welch's method to the bandpass filter method. Third, the frequency domain signal-to-noise ratio for a sine wave in white noise is derived. This derivation includes the computation of the noise floor due to quantization noise. The signal-to-noise ratio and noise flood depend on the FFT length and window. Fourth, the variance the Welch's PSD is discussed via chi-square random variables and degrees of freedom. This report contains many examples, figures and tables to illustrate the concepts. 26 refs.

  19. Density waves in the shearing sheet I. Swing amplification

    E-Print Network [OSTI]

    B. Fuchs

    2001-03-02T23:59:59.000Z

    The shearing sheet model of a galactic disk is studied anew. The theoretical description of its dynamics is based on three building blocks: Stellar orbits, which are described here in epicyclic approximation, the collisionless Boltzmann equation determining the distribution function of stars in phase space, and the Poisson equation in order to take account of the self-gravity of the disk. Using these tools I develop a new formalism to describe perturbations of the shearing sheet. Applying this to the unbounded shearing sheet model I demonstrate again how the disturbances of the disk evolve always into `swing amplified' density waves, i.e. spiral-arm like, shearing density enhancements, which grow and decay while the wave crests swing by from leading to trailing orientation. Several examples are given how such `swing amplification' events are incited in the shearing sheet.

  20. Penetration and scattering of lower hybrid waves by density fluctuations

    SciTech Connect (OSTI)

    Horton, W. [Institute for Fusion Studies, University of Texas at Austin (United States); Goniche, M.; Peysson, Y.; Decker, J.; Ekedahl, A.; Litaudon, X. [CEA, IRFM, F-13108 St-Paul-Lez-Durance (France)

    2014-02-12T23:59:59.000Z

    Lower Hybrid [LH] ray propagation in toroidal plasma is controlled by a combination of the azimuthal spectrum launched from the antenna, the poloidal variation of the magnetic field, and the scattering of the waves by the density fluctuations. The width of the poloidal and radial RF wave spectrum increases rapidly as the rays penetrate into higher density and scatter from the turbulence. The electron temperature gradient [ETG] spectrum is particularly effective in scattering the LH waves due to its comparable wavelengths and parallel phase velocities. ETG turbulence is also driven by the radial gradient of the electron current density giving rise to an anomalous viscosity spreading the LH-driven plasma currents. The scattered LH spectrum is derived from a Fokker-Planck equation for the distribution of the ray trajectories with a diffusivity proportional to the fluctuations. The LH ray diffusivity is large giving transport in the poloidal and radial wavenumber spectrum in one - or a few passes - of the rays through the core plasma.

  1. Langlee Wave Power AS | Open Energy Information

    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 onYou are now leaving Energy.gov You are now leaving Energy.gov YouKizildere I Geothermal Pwer Plant Jump to:Landowners and Wind Energy Development Jump to:Wave Power AS Jump to:

  2. Disk heating by more than one spiral density wave

    E-Print Network [OSTI]

    I. Minchev; A. C. Quillen

    2005-11-01T23:59:59.000Z

    We consider a differentially rotating, 2D stellar disk perturbed by two steady state spiral density waves moving at different patterns speeds. Our investigation is based on direct numerical integration of initially circular test-particle orbits. We examine a range of spiral strengths and spiral speeds and show that stars in this time dependent gravitational field can be heated (their random motions increased).This is particularly noticeable in the simultaneous propagation of a 2-armed spiral density wave near the corotation resonance (CR), and a weak 4-armed one near the inner and outer 4:1 Lindblad resonances. In simulations with 2 spiral waves moving at different pattern speeds we find: (1) the variance of the radial velocity, sigma_R^2, exceeds the sum of the variances measured from simulations with each individual pattern; (2) sigma_R^2 can grow with time throughout the entire simulation; (3) sigma_R^2 is increased over a wider range of radii compared to that seen with one spiral pattern; (4) particles diffuse radially in real space whereas they don't when only one spiral density wave is present. Near the CR with the stronger, 2-armed pattern, test particles are observed to migrate radially. These effects take place at or near resonances of both spirals so we interpret them as the result of stochastic motions. This provides a possible new mechanism for increasing the stellar velocity dispersion in galactic disks. If multiple spiral patterns are present in the Galaxy we predict that there should be large variations in the stellar velocity dispersion as a function of radius.

  3. Radial disk heating by more than one spiral density wave

    E-Print Network [OSTI]

    I. Minchev; A. C. Quillen

    2005-10-28T23:59:59.000Z

    We consider a differentially rotating, 2D stellar disk perturbed by two steady state spiral density waves moving at different patterns speeds. Our investigation is based on direct numerical integration of initially circular test-particle orbits. We examine a range of spiral strengths and spiral speeds and show that stars in this time dependent gravitational field can be heated (their random motions increased). This is particularly noticeable in the simultaneous propagation of a 2-armed spiral density wave near the corotation resonance (CR), and a weak 4-armed one near the inner and outer 4:1 Lindblad resonances. In simulations with 2 spiral waves moving at different pattern speeds we find: (1) the variance of the radial velocity, sigma_R^2, exceeds the sum of the variances measured from simulations with each individual pattern; (2) sigma_R^2 can grow with time throughout the entire simulation; (3) sigma_R^2 is increased over a wider range of radii compared to that seen with one spiral pattern; (4) particles diffuse radially in real space whereas they don't when only one spiral density wave is present. Near the CR with the stronger, 2-armed pattern, test particles are observed to migrate radially. These effects take place at or near resonances of both spirals so we interpret them as the result of stochastic motions. This provides a possible new mechanism for increasing the stellar velocity dispersion in galactic disks. If multiple spiral patterns are present in the Galaxy we predict that there should be large variations in the stellar velocity dispersion as a function of radius.

  4. NO FLARES FROM GAMMA-RAY BURST AFTERGLOW BLAST WAVES ENCOUNTERING SUDDEN CIRCUMBURST DENSITY CHANGE

    SciTech Connect (OSTI)

    Gat, Ilana; Van Eerten, Hendrik; MacFadyen, Andrew [Center for Cosmology and Particle Physics, Physics Department, New York University, New York, NY 10003 (United States)

    2013-08-10T23:59:59.000Z

    Afterglows of gamma-ray bursts are observed to produce light curves with the flux following power-law evolution in time. However, recent observations reveal bright flares at times on the order of minutes to days. One proposed explanation for these flares is the interaction of a relativistic blast wave with a circumburst density transition. In this paper, we model this type of interaction computationally in one and two dimensions, using a relativistic hydrodynamics code with adaptive mesh refinement called RAM, and analytically in one dimension. We simulate a blast wave traveling in a stellar wind environment that encounters a sudden change in density, followed by a homogeneous medium, and compute the observed radiation using a synchrotron model. We show that flares are not observable for an encounter with a sudden density increase, such as a wind termination shock, nor for an encounter with a sudden density decrease. Furthermore, by extending our analysis to two dimensions, we are able to resolve the spreading, collimation, and edge effects of the blast wave as it encounters the change in circumburst medium. In all cases considered in this paper, we find that a flare will not be observed for any of the density changes studied.

  5. Pelamis Wave Power Ocean Power Delivery Ltd | Open Energy Information

    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 onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnual SiteofEvaluatingGroup |JilinLuOpenNorthOlympiaAnalysis)Pearl River Valley ElPelamis Wave Power

  6. High-Efficiency and High-Power CMOS Power Amplifiers for Millimeter-Wave Applications /

    E-Print Network [OSTI]

    Agah, Amir

    2013-01-01T23:59:59.000Z

    large output powers at the millimeter-wave regime has been mainly focused on power combining techniques, using Wilkinson combiners and transformer-

  7. Spiral density waves in the outer galactic gaseous discs

    E-Print Network [OSTI]

    Khoperskov, S A

    2015-01-01T23:59:59.000Z

    Deep HI observations of the outer parts of disc galaxies demonstrate the frequent presence of extended, well-developed spiral arms far beyond the optical radius. To understand the nature and the origin of such outer spiral structure, we investigate the propagation in the outer gaseous disc of large-scale spiral waves excited in the bright optical disc. Using hydrodynamical simulations, we show that non-axisymmetric density waves, penetrating in the gas through the outer Lindblad resonance, can exhibit relatively regular spiral structures outside the bright optical stellar disc. For low-amplitude structures, the results of numerical simulations match the predictions of a simple WKB linear theory. The amplitude of spiral structure increases rapidly with radius. Beyond $\\approx 2$ optical radii, spirals become nonlinear (the linear theory becomes quantitatively and qualitatively inadequate) and unstable to Kelvin-Helmholtz instability. In numerical simulations, in models for which gas is available very far out, ...

  8. Sandia National Laboratories: convert wave power into electricity

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

    wave power into electricity WEC-Sim Code Development Meeting at the National Renewable Energy Laboratory On April 29, 2014, in Computational Modeling & Simulation, Energy, News,...

  9. Wave Power: Destroyer of Rocks; Creator of Clean Energy

    Broader source: Energy.gov [DOE]

    Presentation covers the topic of wave power at the Federal Utility Partnership Working Group (FUPWG) meeting, held on November 18-19, 2009.

  10. STANDING WAVE PROBES FOR DIMENSIONAL METROLOGY OF LOW DENSITY FOAMS

    SciTech Connect (OSTI)

    Seugling, R M; Woody, S C; Bauza, M B

    2010-03-23T23:59:59.000Z

    Typically, parts and geometries of interest to LLNL are made from a combination of complex geometries and a wide array of different materials ranging from metals and ceramics to low density foams and plastic foils. These parts are combined to develop physics experiments for studying material properties, equation of state (EOS) and radiation transport. Understanding the dimensional uncertainty of the parts contained within an experiment is critical to the physical understanding of the phenomena being observed and represents the motivation for developing probe metrology capability that can address LLNL's unique problems. Standing wave probes were developed for measuring high aspect ratio, micrometer scaled features with nanometer resolution. Originally conceived of for the use in the automotive industry for characterizing fuel injector bores and similar geometries, this concept was investigated and improved for use on geometries and materials important to LLNL needs within target fabrication. As part of the original project, detailed understanding of the probe dynamics and interactions with the surface of the sample was investigated. In addition, the upgraded system was utilized for measuring fuel injector bores and micro-lenses as a means of demonstrating capability. This report discusses the use of the standing wave probe for measuring features in low density foams, 55 mg/cc SiO{sub 2} and 982 mg/cc (%6 relative density) copper foam respectively. These two foam materials represent a difficult metrology challenge because of their material properties and surface topography. Traditional non-contact metrology systems such as normal incident interferometry and/or confocal microscopy have difficulty obtaining a signal from the relatively absorptive characteristics of these materials. In addition to the foam samples, a solid copper and plastic (Rexolite{trademark}) sample of similar geometry was measured with the standing wave probe as a reference for both conductive and dielectric materials.

  11. Spatiotemporal evolution of dielectric driven cogenerated dust density waves

    SciTech Connect (OSTI)

    Sarkar, Sanjib; Bose, M. [Department of Physics, Jadavpur University, Kolkata 700032 (India)] [Department of Physics, Jadavpur University, Kolkata 700032 (India); Mukherjee, S. [FCIPT, Institute for Plasma Research, Gandhinagar 382428 (India)] [FCIPT, Institute for Plasma Research, Gandhinagar 382428 (India); Pramanik, J. [Kharagpur College, Kharagpur 721305, West Bengal (India)] [Kharagpur College, Kharagpur 721305, West Bengal (India)

    2013-06-15T23:59:59.000Z

    An experimental observation of spatiotemporal evolution of dust density waves (DDWs) in cogenerated dusty plasma in the presence of modified field induced by glass plate is reported. Various DDWs, such as vertical, oblique, and stationary, were detected simultaneously for the first time. Evolution of spatiotemporal complexity like bifurcation in propagating wavefronts is also observed. As dust concentration reaches extremely high value, the DDW collapses. Also, the oblique and nonpropagating mode vanishes when we increase the number of glass plates, while dust particles were trapped above each glass plates showing only vertical DDWs.

  12. Reaction force control implementation of a linear generator in irregular waves for a wave power system 

    E-Print Network [OSTI]

    Li, Bin

    2012-11-29T23:59:59.000Z

    Most designs for wave energy converters include a hydraulic (or pneumatic) interface between the wave device and the generator to smooth electricity production, but a direct drive power take-off system is a possible way ...

  13. Liquid Walls Innovative High Power Density Concepts

    E-Print Network [OSTI]

    California at Los Angeles, University of

    Surface Heat Flux > 2 MW/m2 2. High Power Conversion Efficiency (> 40%) 3. High Availability -Lower rrr ×= V r J r PV r B r 1P 2P g r + - V r #12;V(initial momentum) g rFluidIn FluidOutBackingWall 2Dsurfaceturbulence · Poloidal Pumping + - J r - flowpoloidal direction - Enhancesurfaceheat transferwith2D turbulence

  14. Wave Power Resources off the Hawaiian Islands luisvega@hawaii.edu Wave Resources for Representative Sites Around the Hawaiian Islands

    E-Print Network [OSTI]

    Wave Power Resources off the Hawaiian Islands luisvega@hawaii.edu 1 Wave Resources for Representative Sites Around the Hawaiian Islands Table of Contents Summary p2 Background: Wave Power Conversion p3 Licensing and Permitting p3 Challenges and Barriers p4 Wave Power Resources: Previous Work p5 Wave

  15. WAVE-ENERGY DENSITY AND WAVE-MOMENTUM DENSITY OF EACH SPECIES OF A COLLISION-LESS PLASMA

    E-Print Network [OSTI]

    Cary, John R.

    2012-01-01T23:59:59.000Z

    case, the electrons have negative wave energy for 2w ne w wave energy for 2w .w > 0 nl Hence, unstable waves with negative phase velocity,

  16. The design of high power density annular fuel for LWRs

    E-Print Network [OSTI]

    Yuan, Yi, 1975-

    2004-01-01T23:59:59.000Z

    Fuel performance models have been developed to assess the performance of internally and externally cooled LWR annular fuel. Such fuel may be operated at 30-50% higher core power density than the current operating LWRs, and ...

  17. An evolutionary fuel assembly design for high power density BWRs

    E-Print Network [OSTI]

    Karahan, Aydin

    2007-01-01T23:59:59.000Z

    An evolutionary BWR fuel assembly design was studied as a means to increase the power density of current and future BWR cores. The new assembly concept is based on replacing four traditional assemblies and large water gap ...

  18. Thin liquid lithium targets for high power density

    E-Print Network [OSTI]

    McDonald, Kirk

    High charge state High velocity flow ~60 m/s High heat capacity of Li Absorbs power depositedThin liquid lithium targets for high power density applications: heavy ion beam strippers and beta Hilton Malmö City #12;Outline Liquid Lithium Stripper idea for FRIB Brief theory of film stability

  19. Density Power Spectrum of Compressible Hydrodynamic Turbulent Flows

    E-Print Network [OSTI]

    Jongsoo Kim; Dongsu Ryu

    2005-07-26T23:59:59.000Z

    Turbulent flows are ubiquitous in astrophysical environments, and understanding density structures and their statistics in turbulent media is of great importance in astrophysics. In this paper, we study the density power spectra, $P_{\\rho}$, of transonic and supersonic turbulent flows through one and three-dimensional simulations of driven, isothermal hydrodynamic turbulence with root-mean-square Mach number in the range of $1 \\la M_{\\rm rms} \\la 10$. From one-dimensional experiments we find that the slope of the density power spectra becomes gradually shallower as the rms Mach number increases. It is because the density distribution transforms from the profile with {\\it discontinuities} having $P_{\\rho} \\propto k^{-2}$ for $M_{\\rm rms} \\sim 1$ to the profile with {\\it peaks} having $P_{\\rho} \\propto k^0$ for $M_{\\rm rms} \\gg 1$. We also find that the same trend is carried to three-dimension; that is, the density power spectrum flattens as the Mach number increases. But the density power spectrum of the flow with $M_{\\rm rms} \\sim 1$ has the Kolmogorov slope. The flattening is the consequence of the dominant density structures of {\\it filaments} and {\\it sheets}. Observations have claimed different slopes of density power spectra for electron density and cold H I gas in the interstellar medium. We argue that while the Kolmogorov spectrum for electron density reflects the {\\it transonic} turbulence of $M_{\\rm rms} \\sim 1$ in the warm ionized medium, the shallower spectrum of cold H I gas reflects the {\\it supersonic} turbulence of $M_{\\rm rms} \\sim$ a few in the cold neutral medium.

  20. Evidence against a charge density wave on Bi(111)

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

    Kim, T.; Wells, J.; Kirkegaard, C.; Li, Z.; Hoffmann, S.; Gayone, J.; Fernandez-Torrente, I.; Haberle, P.; Pascual, J.; Moore, K.; Schwartz, A.; He, H.; Spence, J.; Downing, K.; Lazar, S.; Tichelaar, F.; Borisenko, S.; Knupfer, M.; Hofmann, Ph.

    2005-08-01T23:59:59.000Z

    The Bi(111) surface was studied by scanning tunneling microscopy (STM), transmission electron microscopy (TEM) and angle-resolved photoemission (ARPES) in order to verify the existence of a recently proposed surface charge density wave (CDW) [Ch. R. Ast and H. H¨ochst Phys. Rev. Lett. 90, 016403 (2003)]. The STM and TEM results to not support a CDW scenario at low temperatures. Furthermore, the quasiparticle interference pattern observed in STM confirms the spin-orbit split character of the surface states which prevents the formation of a CDW, even in the case of good nesting. The dispersion of the electronic states observed with ARPES agrees well with earlier findings. In particular, the Fermi contour of the electron pocket at the centre of the surface Brillouin zone is found to have a hexagonal shape. However, no gap opening or other signatures of a CDW phase transition can be found in the temperature-dependent data.

  1. On the Power Spectrum Density of Gamma Ray Bursts

    E-Print Network [OSTI]

    Motoko Suzuki; Masahiro Morikawa; Izumi Joichi

    2001-04-13T23:59:59.000Z

    Gamma ray bursts (GRBs) are known to have short-time variability and power-law behavior with the index -1.67 in the power spectrum density. Reanalyzing the expanded data, we have found a) the power-law comes from the global profile of the burst and not from the self-similar shots nor rapid fluctuations in the luminosity profile. b) The power indices vary from burst to burst and the value -1.67 is given simply as the mean value of the distribution; there is no systematic correlation among GRBs to yield the power law.

  2. No evidence for the blue-tilted power spectrum of relic gravitational waves

    E-Print Network [OSTI]

    Huang, Qing-Guo

    2015-01-01T23:59:59.000Z

    In this paper, we constrain the tilt of the power spectrum of relic gravitational waves by combining the data from BICEP2/Keck array and Planck (BKP) and the Laser Interferometer Gravitational-Waves Observatory (LIGO). From the data of BKP B-modes, the constraint on the tensor tilt is $n_t=0.66^{+1.83}_{-1.44}$ at the $68%$ confidence level. By further adding the LIGO upper limit on the energy density of gravitational waves, the constraint becomes $n_t=-0.76^{+1.37}_{-0.52}$ at the $68%$ confidence level. We conclude that there is no evidence for a blue-tilted power spectrum of relic gravitational waves and either sign of the index of tensor power spectrum is compatible with the data.

  3. No evidence for the blue-tilted power spectrum of relic gravitational waves

    E-Print Network [OSTI]

    Qing-Guo Huang; Sai Wang

    2015-02-09T23:59:59.000Z

    In this paper, we constrain the tilt of the power spectrum of relic gravitational waves by combining the data from BICEP2/Keck array and Planck (BKP) and the Laser Interferometer Gravitational-Waves Observatory (LIGO). From the data of BKP B-modes, the constraint on the tensor tilt is $n_t=0.66^{+1.83}_{-1.44}$ at the $68%$ confidence level. By further adding the LIGO upper limit on the energy density of gravitational waves, the constraint becomes $n_t=-0.76^{+1.37}_{-0.52}$ at the $68%$ confidence level. We conclude that there is no evidence for a blue-tilted power spectrum of relic gravitational waves and either sign of the index of tensor power spectrum is compatible with the data.

  4. Power Maximization in Wave-Energy Converters Using Sampled -Data Extremum Seeking /

    E-Print Network [OSTI]

    Chen, Tianjia

    2013-01-01T23:59:59.000Z

    Power Maximization in Wave-Energy Converters Using Sampled-design optimization of wave energy converters con- sistingN. Sahinkaya. A review of wave energy converter technology.

  5. WAVE-ENERGY DENSITY AND WAVE-MOMENTUM DENSITY OF EACH SPECIES OF A COLLISION-LESS PLASMA

    E-Print Network [OSTI]

    Cary, John R.

    2012-01-01T23:59:59.000Z

    case, the electrons have negative wave energy for 2w ne w wave energy for 2w . > w > 0 nlw/k to the negative wave energy of the electrons. positive

  6. Unraveling the origin of the pseudogap in a charge density wave...

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

    charge density waves has also been associated with phenomena in materials that can superconduct, or conduct electricity perfectly without any loss at extremely low temperatures,...

  7. Thermal Properties of Graphene and Applications for Thermal Management of High-Power Density Electronics

    E-Print Network [OSTI]

    Yan, Zhong

    2013-01-01T23:59:59.000Z

    the development of high-power density semiconductor devices.Management of High-Power Density Electronics A DissertationManagement of High-Power Density Electronics by Zhong Yan

  8. Limits to the power density of very large wind farms

    E-Print Network [OSTI]

    Nishino, Takafumi

    2013-01-01T23:59:59.000Z

    A simple analysis is presented concerning an upper limit of the power density (power per unit land area) of a very large wind farm located at the bottom of a fully developed boundary layer. The analysis suggests that the limit of the power density is about 0.38 times $\\tau_{w0}U_{F0}$, where $\\tau_{w0}$ is the natural shear stress on the ground (that is observed before constructing the wind farm) and $U_{F0}$ is the natural or undisturbed wind speed averaged across the height of the farm to be constructed. Importantly, this implies that the maximum extractable power from such a very large wind farm will not be proportional to the cubic of the wind speed at the farm height, or even the farm height itself, but be proportional to $U_{F0}$.

  9. Protective, Modular Wave Power Generation System

    SciTech Connect (OSTI)

    Vvedensky, Jane M.; Park, Robert Y.

    2012-11-27T23:59:59.000Z

    The concept of small wave energy conversion modules that can be built into large, scalable arrays, in the same vein as solar panels, has been developed. This innovation lends itself to an organic business and development model, and enables the use of large-run manufacturing technology to reduce system costs. The first prototype module has been built to full-scale, and tested in a laboratory wave channel. The device has been shown to generate electricity and dissipate wave energy. Improvements need to be made to the electrical generator and a demonstration of an array of modules should be made in natural conditions.

  10. Turbulent structure of high-density suspensions formed under waves Michael P. Lamb

    E-Print Network [OSTI]

    ; KEYWORDS: wave boundary layer, oscillatory, high-density suspension, fluid mud, turbulent kinetic energy on the interactions between turbulent wave boundary layers and a predominantly silt-sized sediment bed. Under a wide, and sediment concentration revealed that the wave boundary layer, while typically >1 cm thick in sediment

  11. IMAGING WITH DIFFUSE PHOTON DENSITY WAVES Maureen A. O'Leary

    E-Print Network [OSTI]

    IMAGING WITH DIFFUSE PHOTON DENSITY WAVES Maureen A. O'Leary A DISSERTATION in PHYSICS Presented Chairperson #12;COPYRIGHT Maureen Ann O'Leary 1996 #12;DEDICATION This work is dedicated to Mom, Dad, Terry v without David's support. #12;ABSTRACT IMAGING WITH DIFFUSE PHOTON DENSITY WAVES Maureen A. O'Leary

  12. Constraints on power spectrum of density fluctuations from PBH evaporations

    E-Print Network [OSTI]

    Edgar Bugaev; Peter Klimai

    2006-12-21T23:59:59.000Z

    We calculate neutrino and photon energy spectra in extragalactic space from evaporation of primordial black holes, assuming that the power spectrum of primordial density fluctuations has a strong bump in the region of small scales. The constraints on the parameters of this bump based on neutrino and photon cosmic background data are obtained.

  13. Power Density Spectra of Gamma-Ray Bursts

    E-Print Network [OSTI]

    Andrei M. Beloborodov

    1999-11-08T23:59:59.000Z

    Power density spectra (PDSs) of long gamma-ray bursts provide useful information on GRBs, indicating their self-similar temporal structure. The best power-law PDSs are displayed by the longest bursts (T_90 > 100 s) in which the range of self-similar time scales covers more than 2 decades. Shorter bursts have apparent PDS slopes more strongly affected by statistical fluctuations. The underlying power law can then be reproduced with high accuracy by averaging the PDSs for a large sample of bursts. This power-law has a slope alpha\\approx -5/3 and a sharp break at 1 Hz. The power-law PDS provides a new sensitive tool for studies of gamma-ray bursts. In particular, we calculate the PDSs of bright bursts in separate energy channels. The PDS flattens in the hard channel (h\

  14. Inferring Magnetospheric Heavy Ion Density using EMIC Waves

    SciTech Connect (OSTI)

    Kim, Eun-Hwa; Johnson, Jay R.; Kim, Hyomin; Lee, Dong-Hun

    2014-05-01T23:59:59.000Z

    We present a method to infer heavy ion concentration ratios from EMIC wave observations that result from ionion hybrid (IIH) resonance. A key feature of the ion-ion hybrid resonance is the concentration of wave energy in a field-aligned resonant mode that exhibits linear polarization. This mode converted wave is localized at the location where the frequency of a compressional wave driver matches the IIH resonance condition, which depends sensitively on the heavy ion concentration. This dependence makes it possible to estimate the heavy ion concentration ratio. In this letter, we evaluate the absorption coefficients at the IIH resonance at Earth's geosynchronous orbit for variable concentrations of He+ and field-aligned wave numbers using a dipole magnetic field. Although wave absorption occurs for a wide range of heavy ion concentrations, it only occurs for a limited range of field-aligned wave numbers such that the IIH resonance frequency is close to, but not exactly the same as the crossover frequency. Using the wave absorption and observed EMIC waves from GOES-12 satellite, we demonstrate how this technique can be used to estimate that the He+ concentration is around 4% near L = 6.6.

  15. 1998 Tutorial on Micro Mechatronics and Micro Robotics Powering 3 Dimensional Microrobots: Power Density Limitations \\Lambda

    E-Print Network [OSTI]

    Fearing, Ron

    is the effective power density of the actuator. As inertia and gravitional forces become less significant for small at the micro­scale. One scaling law that is helpful for micro­actuators is the increased break down field

  16. Temperature Power Law of Equilibrium Heavy Particle Density

    E-Print Network [OSTI]

    Sh. Matsumoto; M. Yoshimura

    1999-10-19T23:59:59.000Z

    A standard calculation of the energy density of heavy stable particles that may pair-annihilate into light particles making up thermal medium is performed to second order of coupling, using the technique of thermal field theory. At very low temperatures a power law of temperature is derived for the energy density of the heavy particle. This is in sharp contrast to the exponentially suppressed contribution estimated from the ideal gas distribution function. The result supports a previous dynamical calculation based on the Hartree approximation, and implies that the relic abundance of dark matter particles is enhanced compared to that based on the Boltzmann equation.

  17. Density waves in the shearing sheet IV. Interaction with a live dark halo

    E-Print Network [OSTI]

    B. Fuchs

    2004-03-01T23:59:59.000Z

    It is shown that if the self-gravitating shearing sheet, a model of a patch of a galactic disk, is embedded in a live dark halo, this has a strong effect on the dynamics of density waves in the sheet. I describe how the density waves and the halo interact via halo particles either on orbits in resonance with the wave or on non-resonant orbits. Contrary to expectation the presence of the halo leads to a very considerable enhancement of the amplitudes of the density waves in the shearing sheet. This effect appears to be the equivalent of the recently reported enhanced growth of bars in numerically simulated stellar disks embedded in live dark halos. Finally I discuss the transfer of linear momentum from a density wave in the sheet to the halo and show that it is mediated only by halo particles on resonant orbits.

  18. Method of measuring reactive acoustic power density in a fluid

    DOE Patents [OSTI]

    Wheatley, J.C.; Swift, G.W.; Migliori, A.

    1985-09-03T23:59:59.000Z

    A method for determining reactive acoustic power density level and its direction in a fluid using a single sensor is disclosed. In the preferred embodiment, an apparatus for conducting the method, which is termed a thermoacoustic couple, consists of a stack of thin, spaced apart polymeric plates, selected ones of which include multiple bimetallic thermocouple junctions positioned along opposite end edges thereof. The thermocouple junctions are connected in series in the nature of a thermopile, and are arranged so as to be responsive to small temperature differences between the opposite edges of the plates. The magnitude of the temperature difference, as represented by the magnitude of the electrical potential difference generated by the thermopile, is found to be directly related to the level of acoustic power density in the gas. 5 figs.

  19. Method of measuring reactive acoustic power density in a fluid

    DOE Patents [OSTI]

    Wheatley, John C. (Los Alamos, NM); Swift, Gregory W. (Los Alamos, NM); Migliori, Albert (Santa Fe, NM)

    1985-01-01T23:59:59.000Z

    A method for determining reactive acoustic power density level and its direction in a fluid using a single sensor is disclosed. In the preferred embodiment, an apparatus for conducting the method, which is termed a thermoacoustic couple, consists of a stack of thin, spaced apart polymeric plates, selected ones of which include multiple bimetallic thermocouple junctions positioned along opposite end edges thereof. The thermocouple junctions are connected in series in the nature of a thermopile, and are arranged so as to be responsive to small temperature differences between the opposite edges of the plates. The magnitude of the temperature difference, as represented by the magnitude of the electrical potential difference generated by the thermopile, is found to be directly related to the level of acoustic power density in the gas.

  20. Power and polarization monitor development for high power millimeter-wave

    SciTech Connect (OSTI)

    Makino, R., E-mail: makino.ryohhei@ms.nifs.ac.jp; Kobayashi, K. [Department of Energy Engineering and Science, Nagoya University, Nagoya 464-8603 (Japan); Kubo, S. [Department of Energy Engineering and Science, Nagoya University, Nagoya 464-8603 (Japan); National Institute for Fusion Science, Toki 509-5292 (Japan); Kobayashi, S.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Takahashi, H.; Mutoh, T. [National Institute for Fusion Science, Toki 509-5292 (Japan)

    2014-11-15T23:59:59.000Z

    A new type monitor of power and polarization states of millimeter-waves has been developed to be installed at a miter-bend, which is a part of transmission lines of millimeter-waves, for electron cyclotron resonance heating on the Large Helical Device. The monitor measures amplitudes and phase difference of the electric field of the two orthogonal polarizations which are needed for calculation of the power and polarization states of waves. The power and phase differences of two orthogonal polarizations were successfully detected simultaneously.

  1. GyPSuM: A Detailed Tomographic Model of Mantle Density and Seismic Wave Speeds

    SciTech Connect (OSTI)

    Simmons, N A; Forte, A M; Boschi, L; Grand, S P

    2010-03-30T23:59:59.000Z

    GyPSuM is a tomographic model fo mantle seismic shear wave (S) speeds, compressional wave (P) speeds and detailed density anomalies that drive mantle flow. the model is developed through simultaneous inversion of seismic body wave travel times (P and S) and geodynamic observations while considering realistic mineral physics parameters linking the relative behavior of mantle properties (wave speeds and density). Geodynamic observations include the (up to degree 16) global free-air gravity field, divergence of the tectonic plates, dynamic topography of the free surface, and the flow-induced excess ellipticity of the core-mantle boundary. GyPSuM is built with the philosophy that heterogeneity that most closely resembles thermal variations is the simplest possible solution. Models of the density field from Earth's free oscillations have provided great insight into the density configuration of the mantle; but are limited to very long-wavelength solutions. Alternatively, simply scaling higher resolution seismic images to density anomalies generates density fields that do not satisfy geodynamic observations. The current study provides detailed density structures in the mantle while directly satisfying geodynamic observations through a joint seismic-geodynamic inversion process. Notable density field observations include high-density piles at the base of the superplume structures, supporting the fundamental results of past normal mode studies. However, these features are more localized and lower amplitude than past studies would suggest. When we consider all seismic anomalies in GyPSuM, we find that P and S-wave speeds are strongly correlated throughout the mantle. However, correlations between the high-velocity S zones in the deep mantle ({approx} 2000 km depth) and corresponding P-wave anomalies are very low suggesting a systematic divergence from simplified thermal effects in ancient subducted slab anomalies. Nevertheless, they argue that temperature variations are the primary cause of P-wave, S-wave, and density anomalies in the mantle.

  2. The number density of quasars as a probe of initial power spectrum on small scale

    E-Print Network [OSTI]

    B. Novosyadlyj; Yu. Chornij

    1998-12-15T23:59:59.000Z

    The dependence of the number density of the bright QSOs at different redshifts ($n_{QSO}(z)$) on initial power spectrum is studied. It is assumed that QSO phenomenon is an early short term stage of evolution of massive galaxies with $M\\geq 2\\times 10^{11}h^{-1}M_{\\odot}$. The duration of such QSO stage which is passed through by fraction $\\alpha$ of galaxies is determined by means of minimization of the divergence of the theoretical number density of QSOs at different redshifts for specified initial spectrum from observable one \\cite{sc91}. It is shown that the nearest number densities of QSOs at $0.7\\le z\\le 3.5$ to observable ones are obtained for the tilted CDM model ($\\Omega_{b}=0.1$, $n=0.7$). The QSO stage lasts $\\sim 7\\times 10^{7}/\\alpha$ years and begins soon after the moment of rise of the first counterflow in collisionless component and shock wave in gas. The possibility of the reconstruction of initial power spectrum on small scale on the base of the observable data on number density of QSOs at different $z$ is considered too. Such reconstructed spectrum in comparison with standard CDM has steep reducing of power at $k\\ge 0.5 h Mpc^{-1}$.

  3. Gravitational wave generation in power-law inflationary models

    E-Print Network [OSTI]

    Paulo M. Sá; Alfredo B. Henriques

    2008-06-06T23:59:59.000Z

    We investigate the generation of gravitational waves in power-law inflationary models. The energy spectrum of the gravitational waves is calculated using the method of continuous Bogoliubov coefficients. We show that, by looking at the interval of frequencies between 10^(-5) and 10^5 Hz and also at the GHz range, important information can be obtained, both about the inflationary period itself and about the thermalization regime between the end of inflation and the beginning of the radiation-dominated era. We thus deem the development of gravitational wave detectors, covering the MHz/GHz range of frequencies, to be an important task for the future.

  4. Distributed delay model for density wave dynamics in gas lifted wells Laure Sin`egre, Nicolas Petit

    E-Print Network [OSTI]

    Distributed delay model for density wave dynamics in gas lifted wells Laure Sin`egre, Nicolas Petit in the tubing D. dynamical choking is used to stabilise the density wave instability. In this paper, we propose instabilities cause production losses. One of these instabilities, referred to as the "density-wave

  5. Advanced, High Power, Next Scale, Wave Energy Conversion Device

    SciTech Connect (OSTI)

    Mekhiche, Mike [Principal Investigator] [Principal Investigator; Dufera, Hiz [Project Manager] [Project Manager; Montagna, Deb [Business Point of Contact] [Business Point of Contact

    2012-10-29T23:59:59.000Z

    The project conducted under DOE contract DE?EE0002649 is defined as the Advanced, High Power, Next Scale, Wave Energy Converter. The overall project is split into a seven?stage, gated development program. The work conducted under the DOE contract is OPT Stage Gate III work and a portion of Stage Gate IV work of the seven stage product development process. The project effort includes Full Concept Design & Prototype Assembly Testing building on our existing PowerBuoy? technology to deliver a device with much increased power delivery. Scaling?up from 150kW to 500kW power generating capacity required changes in the PowerBuoy design that addressed cost reduction and mass manufacturing by implementing a Design for Manufacturing (DFM) approach. The design changes also focused on reducing PowerBuoy Installation, Operation and Maintenance (IO&M) costs which are essential to reducing the overall cost of energy. In this design, changes to the core PowerBuoy technology were implemented to increase capability and reduce both CAPEX and OPEX costs. OPT conceptually envisaged moving from a floating structure to a seabed structure. The design change from a floating structure to seabed structure would provide the implementation of stroke? unlimited Power Take?Off (PTO) which has a potential to provide significant power delivery improvement and transform the wave energy industry if proven feasible.

  6. Interaction of waves in a two-layer density stratified fluid

    E-Print Network [OSTI]

    Alam, Mohammad-Reza

    2008-01-01T23:59:59.000Z

    In the first part of this thesis, the mechanisms of nonlinear resonant interaction of surface-interfacial waves with a rippled bottom in a two-layer density stratified fluid in two dimensions is investigated via perturbation ...

  7. Protostellar fragmentation in a power-law density distribution

    E-Print Network [OSTI]

    A. Burkert; M. Bate; P. Bodenheimer

    1997-06-10T23:59:59.000Z

    Hydrodynamical calculations in three space dimensions of the collapse of an isothermal, rotating 1 M\\sol protostellar cloud are presented. The initial density stratification is a power law with density $\\rho \\propto r^{-p}$, with $p=1$. The case of the singular isothermal sphere ($p=2$) is not considered; however $p=1$ has been shown observationally to be a good representation of the density distribution in molecular cloud cores just before the beginning of collapse. The collapse is studied with two independent numerical methods, an SPH code with 200,000 particles, and a finite-difference code with nested grids which give high spatial resolution in the inner regions. Although previous numerical studies have indicated that such a power-law distribution would not result in fragmentation into a binary system, both codes show, in contrast, that multiple fragmentation does occur in the central regions of the protostar. Thus the process of binary formation by fragmentation is shown to be consistent with the fact that a large fraction of young stars are observed to be in binary or multiple systems.

  8. A Comprehensive Study of Fracture Patterns and Densities in The Geysers Geothermal Reservoir Using Microearthquake Shear-Wave Splitting Tomography

    SciTech Connect (OSTI)

    Peter E. Malin; Eylon Shalev; Min Lou; Silas M. Simiyu; Anastasia Stroujkova; Windy McCausland

    2004-02-24T23:59:59.000Z

    In this project we developed a method for using seismic S-wave data to map the patterns and densities of sub-surface fractures in the NW Geysers Geothermal Field/ (1) This project adds to both the general methods needed to characterize the geothermal production fractures that supply steam for power generation and to the specific knowledge of these in the Geysers area. (2)By locating zones of high fracture density it will be possible to reduce the cost of geothermal power development with the targeting of high production geothermal wells. (3) The results of the project having been transferred to both US based and international geothermal research and exploration agencies and concerns by several published papers and meeting presentations, and through the distribution of the data handling and other software codes we developed.

  9. Modeling the propagation of whistler-mode waves in the presence of field-aligned density irregularities

    E-Print Network [OSTI]

    California at Los Angles, University of

    Modeling the propagation of whistler-mode waves in the presence of field-aligned density of VLF whistler-mode waves in a laboratory plasma. Our goal is to understand whistler propagation) whistler in a density enhancement. Results from a numerical simulation of whistler wave propagation

  10. A powerful reflector in relativistic backward wave oscillator

    SciTech Connect (OSTI)

    Cao, Yibing, E-mail: caoyibing@nint.ac.cn; Sun, Jun; Teng, Yan; Zhang, Yuchuan; Zhang, Lijun; Shi, Yanchao; Ye, Hu; Chen, Changhua [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024 (China)

    2014-09-15T23:59:59.000Z

    An improved TM{sub 021} resonant reflector is put forward. Similarly with most of the slow wave structures used in relativistic backward wave oscillator, the section plane of the proposed reflector is designed to be trapezoidal. Compared with the rectangular TM{sub 021} resonant reflector, such a structure can depress RF breakdown more effectively by weakening the localized field convergence and realizing good electrostatic insulation. As shown in the high power microwave (HPM) generation experiments, with almost the same output power obtained by the previous structure, the improved structure can increase the pulse width from 25?ns to over 27?ns and no obvious surface damage is observed even if the generated HPM pulses exceed 1000 shots.

  11. Constraining the gravitational wave energy density of the Universe using Earth's ring

    E-Print Network [OSTI]

    Michael Coughlin; Jan Harms

    2014-06-04T23:59:59.000Z

    The search for gravitational waves is one of today's major scientific endeavors. A gravitational wave can interact with matter by exciting vibrations of elastic bodies. Earth itself is a large elastic body whose so-called normal-mode oscillations ring up when a gravitational wave passes. Therefore, precise measurement of vibration amplitudes can be used to search for the elusive gravitational-wave signals. Earth's free oscillations that can be observed after high-magnitude earthquakes have been studied extensively with gravimeters and low-frequency seismometers over many decades leading to invaluable insight into Earth's structure. Making use of our detailed understanding of Earth's normal modes, numerical models are employed for the first time to accurately calculate Earth's gravitational-wave response, and thereby turn a network of sensors that so far has served to improve our understanding of Earth, into an astrophysical observatory exploring our Universe. In this article, we constrain the energy density of gravitational waves to values in the range 0.035 - 0.15 normalized by the critical energy density of the Universe at frequencies between 0.3mHz and 5mHz, using 10 years of data from the gravimeter network of the Global Geodynamics Project that continuously monitors Earth's oscillations. This work is the first step towards a systematic investigation of the sensitivity of gravimeter networks to gravitational waves. Further advance in gravimeter technology could improve sensitivity of these networks and possibly lead to gravitational-wave detection.

  12. Constraining the gravitational wave energy density of the Universe using Earth's ring

    E-Print Network [OSTI]

    Coughlin, Michael

    2014-01-01T23:59:59.000Z

    The search for gravitational waves is one of today's major scientific endeavors. A gravitational wave can interact with matter by exciting vibrations of elastic bodies. Earth itself is a large elastic body whose so-called normal-mode oscillations ring up when a gravitational wave passes. Therefore, precise measurement of vibration amplitudes can be used to search for the elusive gravitational-wave signals. Earth's free oscillations that can be observed after high-magnitude earthquakes have been studied extensively with gravimeters and low-frequency seismometers over many decades leading to invaluable insight into Earth's structure. Making use of our detailed understanding of Earth's normal modes, numerical models are employed for the first time to accurately calculate Earth's gravitational-wave response, and thereby turn a network of sensors that so far has served to improve our understanding of Earth, into an astrophysical observatory exploring our Universe. In this article, we constrain the energy density o...

  13. Brain Tissue Depth (mm) LightPowerDensity(mW/mm2

    E-Print Network [OSTI]

    Schnitzer, Mark

    Brain Tissue Depth (mm) LightPowerDensity(mW/mm2 ) Power Meter Tissue block Bare Fiber = 12° = 6 with the beveled cannula over CeA. d) Chart indicating estimated light power density seen at various distances from the fiber tip in mouse brain tissue when the light power density seen at the fiber tip was 7 mW (~99 mW/mm2

  14. Power-law tails in probability density functions of molecular cloud column density

    E-Print Network [OSTI]

    Brunt, Chris

    2015-01-01T23:59:59.000Z

    Power-law tails are often seen in probability density functions (PDFs) of molecular cloud column densities, and have been attributed to the effect of gravity. We show that extinction PDFs of a sample of five molecular clouds obtained at a few tenths of a parsec resolution, probing extinctions up to A$_{{\\mathrm{V}}}$ $\\sim$ 10 magnitudes, are very well described by lognormal functions provided that the field selection is tightly constrained to the cold, molecular zone and that noise and foreground contamination are appropriately accounted for. In general, field selections that incorporate warm, diffuse material in addition to the cold, molecular material will display apparent core+tail PDFs. The apparent tail, however, is best understood as the high extinction part of a lognormal PDF arising from the cold, molecular part of the cloud. We also describe the effects of noise and foreground/background contamination on the PDF structure, and show that these can, if not appropriately accounted for, induce spurious ...

  15. The Column Density Distribution of the Lyman-Alpha Forest: A Measure of Small Scale Power

    E-Print Network [OSTI]

    Lam Hui; Nickolay Y. Gnedin; Yu Zhang

    1997-02-19T23:59:59.000Z

    Absorption lines in the Lyman-alpha forest can be thought of as peaks in neutral hydrogen density along lines of sight. The column density distribution (the number density of absorption lines as a function of column density) is then a statistic of density peaks, which contains information about the underlying power spectrum. In particular, we show that the slope of the distribution provides a measure of power on scales smaller than those probed by studies of present-day large scale structure.

  16. Interplay of superconductivity, magnetism, and density waves in rare-earth tritellurides and iron-based superconducting materials

    E-Print Network [OSTI]

    Zocco, Diego Andrés

    2011-01-01T23:59:59.000Z

    3. Magnetism in Metals . . . . . . . . . . . . . . . . .IV Superconductivity and Magnetism in Iron-PnictideIII Superconductivity, Magnetism and Charge-Density Waves in

  17. Predictive Power Control of Doubly-Fed Induction Generator for Wave Energy Converters

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Predictive Power Control of Doubly-Fed Induction Generator for Wave Energy Converters M.S. Lagoun1. There are several wave energy converters to harness this energy. Some of them, as in tidal applications, use of a DFIG-based Wave Energy Converter (WEC). In the proposed control approach, the predicted output power

  18. Edinburgh University aka Wave Power Group | Open Energy Information

    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 onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand JumpConceptual Model,DOEHazel Crest, Illinois:Edinburgh University aka Wave Power Group Jump to:

  19. A Predictive power control of Doubly Fed Induction Generator for Wave Energy Converter

    E-Print Network [OSTI]

    Brest, Université de

    A Predictive power control of Doubly Fed Induction Generator for Wave Energy Converter in Irregular there are several wave energy converters to harness this energy. Some of them, as in tidal applications, use based Wave Energy Converter under irregular wave climate which is modeled as time series elevation from

  20. Shock waves in a Z-pinch and the formation of high energy density plasma

    SciTech Connect (OSTI)

    Rahman, H. U. [Magneto-Inertial Fusion Technologies Inc. (MIFTI), Irvine, California 92612 (United States) and Department of Physics, University of California Irvine, Irvine, California 92697 (United States); Wessel, F. J. [Department of Physics, University of California Irvine, Irvine California 92697 (United States); Ney, P. [Mount San Jacinto College, Menifee, California 92584 (United States); Presura, R. [University of Nevada, Reno, 1664 N. Virginia St., Reno, Nevada 89557-0208 (United States); Ellahi, Rahmat [Department of Mathematics and Statistics, FBAS, IIU, Islamabad (Pakistan) and Department of Mechanical Engineering, University of California Riverside, Riverside, California 92521 (United States); Shukla, P. K. [Department of Mechanical and Aerospace Engineering and Center for Energy Research, University of California San Diego, La Jolla, California 92093 (United States)

    2012-12-15T23:59:59.000Z

    A Z-pinch liner, imploding onto a target plasma, evolves in a step-wise manner, producing a stable, magneto-inertial, high-energy-density plasma compression. The typical configuration is a cylindrical, high-atomic-number liner imploding onto a low-atomic-number target. The parameters for a terawatt-class machine (e.g., Zebra at the University of Nevada, Reno, Nevada Terawatt Facility) have been simulated. The 2-1/2 D MHD code, MACH2, was used to study this configuration. The requirements are for an initial radius of a few mm for stable implosion; the material densities properly distributed, so that the target is effectively heated initially by shock heating and finally by adiabatic compression; and the liner's thickness adjusted to promote radial current transport and subsequent current amplification in the target. Since the shock velocity is smaller in the liner, than in the target, a stable-shock forms at the interface, allowing the central load to accelerate magnetically and inertially, producing a magneto-inertial implosion and high-energy density plasma. Comparing the implosion dynamics of a low-Z target with those of a high-Z target demonstrates the role of shock waves in terms of compression and heating. In the case of a high-Z target, the shock wave does not play a significant heating role. The shock waves carry current and transport the magnetic field, producing a high density on-axis, at relatively low temperature. Whereas, in the case of a low-Z target, the fast moving shock wave preheats the target during the initial implosion phase, and the later adiabatic compression further heats the target to very high energy density. As a result, the compression ratio required for heating the low-Z plasma to very high energy densities is greatly reduced.

  1. The inverse conductivity problem with power densities in dimension n2

    E-Print Network [OSTI]

    François Monard, Guillaume Bal

    2012-06-19T23:59:59.000Z

    Jun 19, 2012 ... The inverse conductivity problem with power densities in dimension n ? 2. François Monard Guillaume Bal. Dept. of Applied Physics and ...

  2. Loops and Power Counting in the High Density Effective Field Theory

    E-Print Network [OSTI]

    Thomas Schaefer

    2003-10-15T23:59:59.000Z

    We introduce the high density effective theory of QCD. We discuss, in particular, the problem of developing a consistent power counting scheme.

  3. Bragg scattering and wave-power extraction by an array of small buoys

    E-Print Network [OSTI]

    Boyer, Edmond

    Bragg scattering and wave-power extraction by an array of small buoys By Xavier Garnaud & Chiang C to power-takeoff devices. The spacing between buoys is assumed to be comparable to the incident wavelength to the potential of power extraction from sea waves by an isolated unit such as a buoy, a raft or an oscillating

  4. High-density thermoelectric power generation and nanoscale thermal metrology

    E-Print Network [OSTI]

    Mayer, Peter (Peter Matthew), 1978-

    2007-01-01T23:59:59.000Z

    Thermoelectric power generation has been around for over 50 years but has seen very little large scale implementation due to the inherently low efficiencies and powers available from known materials. Recent material advances ...

  5. A High Power Density DC-DC Converter for Distributed PV Architectures

    SciTech Connect (OSTI)

    Mohammed S. Agamy; Song Chi; Ahmed Elasser; Maja Harfman-Todorovic; Yan Jiang; Frank Mueller; Fengfeng Tao

    2012-06-01T23:59:59.000Z

    In order to maximize solar energy harvesting capabilities, power converters have to be designed for high efficiency and good MPPT and voltage/current performance. When many converters are used in distributed systems, power density also becomes an important factor as it allows for simpler system integration. In this paper a high power density string dc-dc converter suitable for distributed medium to large scale PV installation is presented. A simple partial power processing topology, implemented with all silicon carbide devices provides high efficiency as well as high power density. A 3.5kW, 100kHz converter is designed and tested to verify the proposed methods.

  6. HII regions in spiral galaxies: Size distribution, luminosity function, and new isochrone diagnostics of density wave kinematics

    E-Print Network [OSTI]

    M. S. Oey; J. S. Parker; V. J. Mikles; X. Zhang

    2003-07-10T23:59:59.000Z

    We investigate the relationship of the HII region luminosity function (HII LF) to the HII region size distribution and density wave triggering in grand-design spiral galaxies. We suggest that the differential nebular size distribution is described by a power law of slope ~ -4, with flattening at radii below ~ 130 pc. This contrasts with the conventional exponential description, but it is physically and quantitatively consistent with the typical observed value of -2 for the HII LF slope. We have developed an interactive code that computes spatial isochrones for the evolving loci of spiral density waves in disk galaxies. This allows comparison of the nebular spatial distribution with the spatial isochrones for simple rotation curve parameters. Our comparisons for four grand-design galaxies suggest that the corotation radius r_co coincides with the outer ends of the star-forming arms. This value for r_co yields the best spatial correspondence between the HII regions and the isochrones, and also appears to yield a coincidence between the Inner Lindblad Resonance with the radial onset of star formation in the arms. Thus, we suggest that isochrones offer a new, simple, and effective technique for determining r_co, and thus the spiral pattern speed. However, application of the isochrones also demonstrates that evolution of the nebular population is difficult to spatially isolate in these galaxies.

  7. Effect of a nonlinear power take off on a wave energy converter 

    E-Print Network [OSTI]

    Bailey, Helen Louise

    2011-11-22T23:59:59.000Z

    This thesis is titled The influence of a nonlinear Power Take Off on a Wave Energy Converter. It looks at the effect that having a nonlinear Power Take Off (PTO) has on an inertial referenced, slack moored, point absorber, ...

  8. Enhanced surfaces lead to increased heat transfer and power density.

    E-Print Network [OSTI]

    electric vehicles (HEVs) and electric vehicles (EVs) to con- vert DC battery power into a form that can IHTC-14, Washington, DC, USA. Moreno, G., 2010,"Characterization and Development of Advanced Heat

  9. Development of a high power density motor for aircraft propulsion

    E-Print Network [OSTI]

    Dibua, Imoukhuede Tim Odion

    2007-04-25T23:59:59.000Z

    are currently powered by heavy gas turbine engines that require fueling. The development of electric motors to replace gas turbines would be a big step towards accomplishing more efficient aircraft propulsion. The primary objective of this research extends...

  10. High-power parametric conversion from near-infrared to short-wave infrared

    E-Print Network [OSTI]

    Dalang, Robert C.

    High-power parametric conversion from near-infrared to short-wave infrared Adrien Billat,1,* Steevy.billat@epfl.ch Abstract: We report the design of an all-fiber continuous wave Short-Wave Infrared source capable to output.4370) Nonlinear optics, fibers; (140.3070) Infrared and far-infrared lasers. References and links 1. M. N

  11. A Framework to Determine the Probability Density Function for the Output Power of Wind Farms

    E-Print Network [OSTI]

    Liberzon, Daniel

    A Framework to Determine the Probability Density Function for the Output Power of Wind Farms Sairaj to the power output of a wind farm while factoring in the availability of the wind turbines in the farm availability model for the wind turbines, we propose a method to determine the wind-farm power output pdf

  12. Spatial profiles of electron and metastable atom densities in positive polarity fast ionization waves sustained in helium

    SciTech Connect (OSTI)

    Weatherford, Brandon R., E-mail: brweathe@gmail.com, E-mail: zax@esi-group.com, E-mail: evbarna@sandia.gov, E-mail: mjkush@umich.edu; Barnat, E. V., E-mail: brweathe@gmail.com, E-mail: zax@esi-group.com, E-mail: evbarna@sandia.gov, E-mail: mjkush@umich.edu [Sandia National Laboratories, Albuquerque, New Mexico 87185-1423 (United States); Xiong, Zhongmin, E-mail: brweathe@gmail.com, E-mail: zax@esi-group.com, E-mail: evbarna@sandia.gov, E-mail: mjkush@umich.edu; Kushner, Mark J., E-mail: brweathe@gmail.com, E-mail: zax@esi-group.com, E-mail: evbarna@sandia.gov, E-mail: mjkush@umich.edu [Department of Electrical Engineering and Computer Science, University of Michigan, Ann Arbor, Michigan 48109-2122, USA. (United States)

    2014-09-14T23:59:59.000Z

    Fast ionization waves (FIWs), often generated with high voltage pulses over nanosecond timescales, are able to produce large volumes of ions and excited states at moderate pressures. The mechanisms of FIW propagation were experimentally and computationally investigated to provide insights into the manner in which these large volumes are excited. The two-dimensional structure of electron and metastable densities produced by short-pulse FIWs sustained in helium were measured using laser-induced fluorescence and laser collision-induced fluorescence diagnostics for times of 100–120?ns after the pulse, as the pressure was varied from 1 to 20?Torr. A trend of center-peaked to volume-filling to wall-peaked electron density profiles was observed as the pressure was increased. Instantaneous FIW velocities, obtained from plasma-induced emission, ranged from 0.1 to 3?×?10{sup 9?}cm s{sup ?1}, depending on distance from the high voltage electrode and pressure. Predictions from two-dimensional modeling of the propagation of a single FIW correlated well with the experimental trends in electron density profiles and wave velocity. Results from the model show that the maximum ionization rate occurs in the wavefront, and the discharge continues to propagate forward after the removal of high voltage from the powered electrode due to the potential energy stored in the space charge. As the pressure is varied, the radial distribution of the ionization rate is shaped by changes in the electron mean free path, and subsequent localized electric field enhancement at the walls or on the centerline of the discharge.

  13. Power density spectrum of NGC 5548 and the nature of its variability

    E-Print Network [OSTI]

    B. Czerny; A. Schwarzenberg-Czerny; Z. Loska

    1998-10-14T23:59:59.000Z

    We derive power density spectra in the optical and X-ray band in the timescale range from several years down to $\\sim $ a day. We suggest that the optical power density spectrum consists of two separate components: long timescale variations and short timescale variations, with the dividing timescale around 100 days. The shape of the short timescale component is similar to X-ray power density spectrum which is consistent with the interpretation of short timescale optical variations being caused by X-ray reprocessing. We show that the observed optical long timescale variability is consistent with thermal pulsations of the accretion disc.

  14. High-Power Density Target Design and Analyses for Accelerator

    E-Print Network [OSTI]

    McDonald, Kirk

    management ­ Lithium · Excellent conductivity, but low heat capacity compared to other coolants ­ Sodium · Better heat capacity than lithium ­ Mercury · Power generation in coolant limits applicability ­ Lithiumcooled Tungsten Plate Liquid Target Concepts ­ Lead Bismuth Eutectic Workshop on Applications of High

  15. Stable formation of ultrahigh power-density 248 nm channels in Xe cluster targets

    SciTech Connect (OSTI)

    Borisov, Alex B.; Racz, Ervin; Khan, Shahab F.; Poopalasingam, Sankar; McCorkindale, John C.; Boguta, John; Longworth, James W.; Rhodes, Charles K. [Laboratory for X-ray Microimaging and Bioinformatics, Department of Physics, University of Illinois at Chicago, Chicago, IL 60607-7059 (United States); KFKI Research Institute for Particle and Nuclear Physics, EURATOM Association, P.O. Box 49, 1525 Budapest (Hungary)

    2012-07-11T23:59:59.000Z

    The optimization of relativistic and ponderomotive self-channeling of ultra-powerful 248 nm laser pulses launched in underdense plasmas with an appropriate longitudinal gradient in the electron density profile located at the initial stage of the self-channeling leads to (1) stable channel formation and (2) highly efficient power compression producing power densities in the 10{sup 19}-10{sup 20} W/cm{sup 3} range. The comparison of theoretical studies with experimental results involving the correlation of (a) Thomson images of the electron density with (b) x-ray images of the channel morphology demonstrates that more than 90% of the incident 248 nm power can be trapped in stable channels and that this stable propagation can be extended to power levels significantly exceeding the critical power of the self-channeling process.

  16. Charge Density Waves in Exfoliated Films of van der Waals Materials: Evolution of Raman Spectrum in TiSe2

    E-Print Network [OSTI]

    Charge Density Waves in Exfoliated Films of van der Waals Materials: Evolution of Raman Spectrum graphene-like mechanical exfoliation of TiSe2 crystals to prepare a set of films with different thicknesses

  17. Electromagnetic Potentials Basis for Energy Density and Power Flux

    E-Print Network [OSTI]

    H. E. Puthoff

    2010-09-26T23:59:59.000Z

    It is well understood that various alternatives are available within EM theory for the definitions of energy density, momentum transfer, EM stress-energy tensor, and so forth. Although the various options are all compatible with the basic equations of electrodynamics (e.g., Maxwell's equations, Lorentz force law, gauge invariance), nonetheless certain alternative formulations lend themselves to being seen as preferable to others with regard to the transparency of their application to physical problems of interest. Here we argue for the transparency of an option based on use of the EM potentials alone.

  18. Development of High Power Density Driveline for Vehicles | Department of

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

    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 DataDepartment of Energy Your Density Isn't Your Destiny:Revised Finding of No53197E T A * S H IMaterials Development of

  19. Development of High Power Density Driveline for Vehicles | Department of

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

    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 DataDepartment of Energy Your Density Isn't Your Destiny:Revised Finding of No53197E T A * S H IMaterials Development ofEnergy 1 DOE

  20. High Power Density Integrated Traction Machine Drive | Department of Energy

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

    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 DataDepartment of Energy Your Density Isn't YourTransport(Fact Sheet), GeothermalGridHYDROGEN TOTechnologyHighLouisianaDepartment of HIGH1

  1. High Power Density Integrated Traction Machine Drive | Department of Energy

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

    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 DataDepartment of Energy Your Density Isn't YourTransport(Fact Sheet), GeothermalGridHYDROGEN TOTechnologyHighLouisianaDepartment of HIGH10

  2. Wind: wind power density GIS data at 50m above ground and 1km...

    Open Energy Info (EERE)

    GIS ... Dataset Activity Stream Wind: wind power density GIS data at 50m above ground and 1km resolution for Ghana from NREL (Abstract):  Raster GIS data, exported as BIL...

  3. Constraining the Power Spectrum Using the Column Density Distribution: a Status Report

    E-Print Network [OSTI]

    Lam Hui

    1997-12-04T23:59:59.000Z

    We review the arguments for how the slope of the column density distribution of the Lyman-alpha forest should depend on the matter power spectrum. The latest progress, presented by various groups in this conference and elsewhere, is summarized.

  4. Development of optimized core design and analysis methods for high power density BWRs

    E-Print Network [OSTI]

    Shirvan, Koroush

    2013-01-01T23:59:59.000Z

    Increasing the economic competitiveness of nuclear energy is vital to its future. Improving the economics of BWRs is the main goal of this work, focusing on designing cores with higher power density, to reduce the BWR ...

  5. Assessment of helical-cruciform fuel rods for high power density LWRs

    E-Print Network [OSTI]

    Conboy, Thomas M

    2010-01-01T23:59:59.000Z

    In order to significantly increase the power density of Light Water Reactors (LWRs), the helical-cruciform (HC) fuel rod assembly has been proposed as an alternative to traditional fuel geometry. The HC assembly is a ...

  6. NEUTRONIC AND THERMAL HYDRAULIC DESIGNS OF ANNULAR FUEL FOR HIGH POWER DENSITY BWRS

    E-Print Network [OSTI]

    Morra, P.

    As a promising new fuel for high power density light water reactors, the feasibility of using annular fuel for BWR services is explored from both thermal hydraulic and neutronic points of view. Keeping the bundle size ...

  7. Wind: wind power density GIS data at 50m above ground and 1km...

    Open Energy Info (EERE)

    file, 50 m wind power density for eastern China. (Purpose): To provide information on the wind resource potential in eastern China. Values range from 0 to 3079 Wm2. (Supplemental...

  8. Evaluation of high power density annular fuel application in the Korean OPR-1000 reactor

    E-Print Network [OSTI]

    Zhang, Liang, Ph. D.. Massachusetts Institute of Technology

    2009-01-01T23:59:59.000Z

    Compared to the traditional solid fuel geometry for PWRs, the internally and externally cooled annular fuel offers the potential to increase the core power density while maintaining or increasing safety margins. It is ...

  9. A High Power-Density Mediator-Free Microfluidic Biophotovoltaic Device for Cyanobacterial Cells

    E-Print Network [OSTI]

    Bombelli, Paolo; Mueller, Thomas; Herling, Therese W.; Howe, Christopher J.; Knowles, Tuomas P. J.

    2014-09-16T23:59:59.000Z

    A High Power-Density Mediator-Free Microfluidic Biophotovoltaic Device for Cyanobacterial Cells Paolo Bombelli,1, a) Thomas Mu¨ller,2, a) Therese W. Herling,2 Christopher J. Howe,1, b) and Tuomas P. J. Knowles2, c) 1)Department of Biochemistry... that achievable through synthetic materials. Here, we devise a platform to harness the large power densities afforded by miniaturised geometries. To this effect, we have developed a soft-lithography approach for the fabrication of microfluidic biophotovoltaic...

  10. The Kinematic Wave Equation (KWE) In Tuesday's interrupted lecture we derived the Kinematic Wave Equation (KWE) for a density

    E-Print Network [OSTI]

    Gibbon, J. D.

    The Kinematic Wave Equation (KWE) In Tuesday's interrupted lecture we derived the Kinematic Wave refer to partial derivatives. Kinematic waves occur when we take Q = Q(), in which case t + c()x = 0 (2) where the propagation velocity is c() = dQ/d. (2) is called the Kinematic Wave Equation (KWE). We wish

  11. The Influence of Isotopic Mass, Edge Magnetic Shear and Input Power on High Density ELMy H-modes in JET

    E-Print Network [OSTI]

    The Influence of Isotopic Mass, Edge Magnetic Shear and Input Power on High Density ELMy H-modes in JET

  12. ICRF Power-Deposition Profiles, Heating and Confinement of Monster-Sawtooth and Peaked-Density Profile Discharges in JET

    E-Print Network [OSTI]

    ICRF Power-Deposition Profiles, Heating and Confinement of Monster-Sawtooth and Peaked-Density Profile Discharges in JET

  13. LOW POWER SCANNER FOR HIGH-DENSITY ELECTRODE ARRAY NEURAL RECORDING

    E-Print Network [OSTI]

    Mahmoodi, Hamid

    of this research is to design a low power integrated system that can be used in vivo for scanning the electrode. A model created in Python provides input vectors and output comparison for the verification processLOW POWER SCANNER FOR HIGH-DENSITY ELECTRODE ARRAY NEURAL RECORDING A Thesis work submitted

  14. Electron Trapping in Shear Alfven Waves that Power the Aurora

    SciTech Connect (OSTI)

    Watt, Clare E. J.; Rankin, Robert [University of Alberta, Edmonton, Alberta (Canada)

    2009-01-30T23:59:59.000Z

    Results from 1D Vlasov drift-kinetic plasma simulations reveal how and where auroral electrons are accelerated along Earth's geomagnetic field. In the warm plasma sheet, electrons become trapped in shear Alfven waves, preventing immediate wave damping. As waves move to regions with larger v{sub Te}/v{sub A}, their parallel electric field decreases, and the trapped electrons escape their influence. The resulting electron distribution functions compare favorably with in situ observations, demonstrating for the first time a self-consistent link between Alfven waves and electrons that form aurora.

  15. The Power Spectrum of Galaxy Density Fluctuations: Current Results and Improved Techniques

    E-Print Network [OSTI]

    Michael S. Vogeley

    1995-08-17T23:59:59.000Z

    The power spectrum of density fluctuations measured from galaxy redshift surveys provides important constraints on models for the formation of large-scale structure. I review current results for the 3-D power spectrum and examine the limitations of current measurements and estimation techniques. To span the decade of wavelength between the scales probed by galaxy surveys and COBE, measure the detailed shape of the power spectrum, and accurately examine the dependence of clustering on galaxy species, we require deeper samples with carefully controlled selection criteria and improved techniques for power spectrum estimation. I describe a new method for estimating the power spectrum that optimally treats survey data with arbitrary geometry and sampling.

  16. Design of Millimeter-Wave Power Ampliers in Silicon /

    E-Print Network [OSTI]

    Kalantari, Nader

    2013-01-01T23:59:59.000Z

    K. Han, “W-Band, 5W Solid-State Power Amplifier/Combiner,”Ended Switching Power Amplifiers,” Solid-State Circuits,Class-E Power Am- plifier in SiGe,” Solid-State Circuits

  17. A comparison of parametric decay of oblique Langmuir wave in high and low density magneto-plasmas

    SciTech Connect (OSTI)

    Shahid, M.; Hussain, A. [Salam Chair in Physics, Government College University, Lahore-54000 (Pakistan) [Salam Chair in Physics, Government College University, Lahore-54000 (Pakistan); Department of Physics, Government College University, Lahore-54000 (Pakistan); Murtaza, G. [Salam Chair in Physics, Government College University, Lahore-54000 (Pakistan)] [Salam Chair in Physics, Government College University, Lahore-54000 (Pakistan)

    2013-09-15T23:59:59.000Z

    The parametric decay instability of an obliquely propagating Langmuir wave into the low-frequency electromagnetic shear Alfven wave and the Left-Handed Circularly Polarized wave has been investigated in an electron-ion plasma, immersed in a uniform external magnetic field. Quantum magneto-hydrodynamic model has been used to find the linear and non-linear response of a high density quantum magneto-plasma. Going to the classical limit (??0) retrieves the results for low density classical plasma. Nonlinear dispersion relations and growth rates are derived with analytically and numerically. It is observed that growth rate in the high density degenerate magneto-plasma increases exponentially, while in the low density classical case it increases logarithmically.

  18. High energy density capacitors for power electronic applications using nano-structure multilayer technology

    SciTech Connect (OSTI)

    Barbee, T.W. Jr.; Johnson, G.W.

    1995-09-01T23:59:59.000Z

    Power electronics applications are currently limited by capacitor size and performance. Only incremental improvements are anticipated in existing capacitor technologies, while significant performance advances are required in energy density and overall performance to meet the technical needs of the applications which are important for U.S. economic competitiveness. One application, the Power Electronic Building Block (PEBB), promises a second electronics revolution in power electronic design. High energy density capacitors with excellent electrical thermal and mechanical performance represent an enabling technology in the PEBB concept. We propose a continuing program to research and develop LLNL`s nano-structure multilayer technologies for making high voltage, high energy density capacitors. Our controlled deposition techniques are capable of synthesizing extraordinarily smooth sub-micron thick layers of dielectric and conductor materials. We have demonstrated that, with this technology, high voltage capacitors with an order of magnitude improvement in energy density are achievable.

  19. Method and apparatus for measuring the momentum, energy, power, and power density profile of intense particle beams

    DOE Patents [OSTI]

    Gammel, George M. (Merrick, NY); Kugel, Henry W. (Somerset, NJ)

    1992-10-06T23:59:59.000Z

    A method and apparatus for determining the power, momentum, energy, and power density profile of high momentum mass flow. Small probe projectiles of appropriate size, shape and composition are propelled through an intense particle beam at equal intervals along an axis perpendicular to the beam direction. Probe projectiles are deflected by collisions with beam particles. The net beam-induced deflection of each projectile is measured after it passes through the intense particle beam into an array of suitable detectors.

  20. High thermal power density heat transfer apparatus providing electrical isolation at high temperature using heat pipes

    SciTech Connect (OSTI)

    Morris, J. F.

    1985-03-19T23:59:59.000Z

    This invention is directed to transferring heat from an extremely high temperature source to an electrically isolated lower temperature receiver. The invention is particularly concerned with supplying thermal power to a thermionic converter from a nuclear reactor with electric isolation. Heat from a high temperature heat pipe is transferred through a vacuum or a gap filled with electrically nonconducting gas to a cooler heat pipe. The heat pipe is used to cool the nuclear reactor while the heat pipe is connected thermally and electrically to a thermionic converter. If the receiver requires greater thermal power density, geometries are used with larger heat pipe areas for transmitting and receiving energy than the area for conducting the heat to the thermionic converter. In this way the heat pipe capability for increasing thermal power densities compensates for the comparatively low thermal power densities through the electrically nonconducting gap between the two heat pipes.

  1. E?H mode transition density and power in two types of inductively coupled plasma configuration

    SciTech Connect (OSTI)

    Wang, Jian; Du, Yin-chang; Zhang, Xiao; Zheng, Zhe; Liu, Yu; Xu, Liang; Wang, Pi; Cao, Jin-xiang, E-mail: jxcao@ustc.edu.cn [Department of Modern Physics, University of Science and Technology of China, Hefei, Anhui 230026 (China)

    2014-07-15T23:59:59.000Z

    E???H transition power and density were investigated at various argon pressures in inductively coupled plasma (ICP) in a cylindrical interlaid chamber. The transition power versus the pressure shows a minimum transition power at 4?Pa (?/?=1) for argon. Then the transition density hardly changes at low pressures (?/??1), but it increases clearly when argon pressure exceeds an appropriate value. In addition, both the transition power and transition density are lower in the re-entrant configuration of ICP compared with that in the cylindrical configuration of ICP. The result may be caused from the decrease of stochastic heating in the re-entrant configuration of ICP. This work is useful to understand E???H mode transition and control the transition points in real plasma processes.

  2. Dynamics and afterglow light curves of gamma-ray burst blast waves encountering a density bump or void

    SciTech Connect (OSTI)

    Uhm, Z. Lucas; Zhang, Bing, E-mail: uhm@pku.edu.cn, E-mail: zhang@physics.unlv.edu [Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China)

    2014-07-01T23:59:59.000Z

    We investigate the dynamics and afterglow light curves of gamma-ray burst blast waves that encounter various density structures (such as bumps, voids, or steps) in the surrounding ambient medium. We present and explain the characteristic response features that each type of density structure in the medium leaves on the forward shock (FS) and reverse shock (RS) dynamics for blast waves with either a long-lived or short-lived RS. We show that when the ambient medium density drops, the blast waves exhibit in some cases a period of an actual acceleration (even during their deceleration stage) due to adiabatic cooling of blast waves. Comparing numerical examples that have different shapes of bumps or voids, we propose a number of consistency tests that must be satisfied by correct modeling of blast waves. Our model results successfully pass these tests. Employing a Lagrangian description of blast waves, we perform a sophisticated calculation of afterglow emission. We show that as a response to density structures in the ambient medium, the RS light curves produce more significant variations than the FS light curves. Some observed features (such as rebrightenings, dips, or slow wiggles) can be more easily explained within the RS model. We also discuss the origin of these different features imprinted on the FS and RS light curves.

  3. Wave-plate structures, power selective optical filter devices, and optical systems using same

    DOE Patents [OSTI]

    Koplow, Jeffrey P. (San Ramon, CA)

    2012-07-03T23:59:59.000Z

    In an embodiment, an optical filter device includes an input polarizer for selectively transmitting an input signal. The device includes a wave-plate structure positioned to receive the input signal, which includes first and second substantially zero-order, zero-wave plates arranged in series with and oriented at an angle relative to each other. The first and second zero-wave plates are configured to alter a polarization state of the input signal passing in a manner that depends on the power of the input signal. Each zero-wave plate includes an entry and exit wave plate each having a fast axis, with the fast axes oriented substantially perpendicular to each other. Each entry wave plate is oriented relative to a transmission axis of the input polarizer at a respective angle. An output polarizer is positioned to receive a signal output from the wave-plate structure and selectively transmits the signal based on the polarization state.

  4. The Space Density of Galaxy Peaks and the Linear Matter Power Spectrum

    E-Print Network [OSTI]

    Rupert A. C. Croft; Enrique Gaztanaga

    1997-01-22T23:59:59.000Z

    One way of recovering information about the initial conditions of the Universe is by measuring features of the cosmological density field which are preserved during gravitational evolution and galaxy formation. In this paper we study the total number density of peaks in a (galaxy) point distribution smoothed with a filter, evaluating its usefulness as a means of inferring the shape of the initial (matter) power spectrum. We find that in numerical simulations which start from Gaussian initial conditions, the peak density follows well that predicted by the theory of Gaussian density fields, even on scales where the clustering is mildly non-linear. For smaller filter scales, $r \\simlt 4-6 \\hmpc$, we see evidence of merging as the peak density decreases with time. On larger scales, the peak density is independent of time. One might also expect it to be fairly robust with respect to variations in biasing, i.e. the way galaxies trace mass fluctuations. We find that this is the case when we apply various biasing prescriptions to the matter distribution in simulations. If the initial conditions are Gaussian, it is possible to use the peak density measured from the evolved field to reconstruct the shape of the initial power spectrum. We describe a stable method for doing this and apply it to several biased and unbiased non-linear simulations. We are able to recover the slope of the linear matter power spectrum on scales $k \\simlt 0.4 \\hmpc^{-1}$. The reconstruction has the advantage of being independent of the cosmological parameters ($\\Omega$, $\\Lambda$, $H_0$) and of the clustering normalisation ($\\sigma_8$). The peak density and reconstructed power spectrum slope therefore promise to be powerful discriminators between popular cosmological scenarios.

  5. Helical spin-density wave in Fe/Cr trilayers with perfect interfaces

    SciTech Connect (OSTI)

    Fishman, R.S.

    1998-07-01T23:59:59.000Z

    Despite the presence of only collinear, commensurate (C) and incommensurate (I) spin-density waves (SDW`s) in bulk Cr, the interfacial steps in Fe/Cr multilayers are now believed to stabilize a helical (H) SDW within the Cr spacer. Yet H SDW`s were first predicted in an Fe/Cr trilayer with perfect interfaces when the orientation of the Fe moments does not favor C ordering: if the number of Cr monolayers is even (odd) and the Fe moments are pointing in the same (opposite) direction, then a C SDW does not gain any coupling energy. Under these circumstances, a simple model verifies that H ordering is indeed favored over 1 ordering provided that the Fermi surface mismatch is sufficiently small or the temperature sufficiently high.

  6. Fast plane wave density functional theory molecular dynamics calculations on multi-GPU machines

    SciTech Connect (OSTI)

    Jia, Weile, E-mail: jiawl@sccas.cn [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China) [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing (China); Fu, Jiyun, E-mail: fujy@sccas.cn [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China) [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China); University of Chinese Academy of Sciences, Beijing (China); Cao, Zongyan, E-mail: zycao@sccas.cn [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China)] [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China); Wang, Long, E-mail: wangl@sccas.cn [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China)] [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China); Chi, Xuebin, E-mail: chi@sccas.cn [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China)] [Supercomputing Center, Computer Network Information Center, Chinese Academy of Sciences, No. 4 South 4th Street, ZhongGuanCun, Beijing 100190 (China); Gao, Weiguo, E-mail: wggao@fudan.edu.cn [School of Mathematical Sciences, Fudan University, 220 Handan Road, Shanghai 200433 (China) [School of Mathematical Sciences, Fudan University, 220 Handan Road, Shanghai 200433 (China); MOE Key Laboratory of Computational Physical Sciences, Fudan University, Shanghai (China); Wang, Lin-Wang, E-mail: lwwang@lbl.gov [Material Science Division, Lawrence Berkeley National Laboratory, One Cyclotron Road Mail Stop 50F Berkeley, CA 94720 (United States)] [Material Science Division, Lawrence Berkeley National Laboratory, One Cyclotron Road Mail Stop 50F Berkeley, CA 94720 (United States)

    2013-10-15T23:59:59.000Z

    Plane wave pseudopotential (PWP) density functional theory (DFT) calculation is the most widely used method for material simulations, but its absolute speed stagnated due to the inability to use large scale CPU based computers. By a drastic redesign of the algorithm, and moving all the major computation parts into GPU, we have reached a speed of 12 s per molecular dynamics (MD) step for a 512 atom system using 256 GPU cards. This is about 20 times faster than the CPU version of the code regardless of the number of CPU cores used. Our tests and analysis on different GPU platforms and configurations shed lights on the optimal GPU deployments for PWP-DFT calculations. An 1800 step MD simulation is used to study the liquid phase properties of GaInP.

  7. Photoemission study of the electronic structure and charge density waves of Na?Ti?Sb?O

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

    Tan, S. Y.; Jiang, J.; Ye, Z. R.; Niu, X. H.; Song, Y.; Zhang, C. L.; Dai, P. C.; Xie, B. P.; Lai, X. C.; Feng, D. L.

    2015-04-30T23:59:59.000Z

    The electronic structure of Na?Ti?Sb?O single crystal is studied by photon energy and polarization dependent angle-resolved photoemission spectroscopy (ARPES). The obtained band structure and Fermi surface agree well with the band structure calculation of Na?Ti?Sb?O in the non-magnetic state, which indicates that there is no magnetic order in Na?Ti?Sb?O and the electronic correlation is weak. Polarization dependent ARPES results suggest the multi-band and multi-orbital nature of Na?Ti?Sb?O. Photon energy dependent ARPES results suggest that the electronic structure of Na?Ti?Sb?O is rather two-dimensional. Moreover, we find a density wave energy gap forms below the transition temperature and reaches 65 meV atmore »7 K, indicating that Na?Ti?Sb?O is likely a weakly correlated CDW material in the strong electron-phonon interaction regime. (author)« less

  8. Coordinated control and network integration of wave power farms 

    E-Print Network [OSTI]

    Nambiar, Anup Jayaprakash

    2012-11-29T23:59:59.000Z

    Significant progress has been made in the development of wave energy converters (WECs) during recent years, with prototypes and farms of WECs being installed in different parts of the world. With increasing sizes of ...

  9. Theoretical modelling of two wave-power devices

    E-Print Network [OSTI]

    Lovas, Stéphanie

    2010-01-01T23:59:59.000Z

    Many wave energy devices are currently studied. In this thesis we focus on two specific devices: the Oscillating Water Column (OWC), and the buoys. In the first part of this thesis we examine the effects of coastline ...

  10. Method of Fabrication of High Power Density Solid Oxide Fuel Cells

    DOE Patents [OSTI]

    Pham, Ai Quoc (San Jose, CA); Glass, Robert S. (Livermore, CA)

    2008-09-09T23:59:59.000Z

    A method for producing ultra-high power density solid oxide fuel cells (SOFCs). The method involves the formation of a multilayer structure cells wherein a buffer layer of doped-ceria is deposited intermediate a zirconia electrolyte and a cobalt iron based electrode using a colloidal spray deposition (CSD) technique. For example, a cobalt iron based cathode composed of (La,Sr)(Co,Fe)O(LSCF) may be deposited on a zirconia electrolyte via a buffer layer of doped-ceria deposited by the CSD technique. The thus formed SOFC have a power density of 1400 mW/cm.sup.2 at 600.degree. C. and 900 mW/cm.sup.2 at 700.degree. C. which constitutes a 2-3 times increased in power density over conventionally produced SOFCs.

  11. 1998 Tutorial on Micro Mechatronics and Micro Robotics Powering 3 Dimensional Microrobots: Power Density Limitations

    E-Print Network [OSTI]

    Fearing, Ron

    density of the actuator. As inertia and gravitional forces become less significant for small robots at the micro-scale. One scaling law that is helpful for micro-actuators is the increased break down field

  12. Power spectrum of electron number density perturbations at cosmological recombination epoch

    E-Print Network [OSTI]

    B. Venhlovska; B. Novosyadlyj

    2009-02-19T23:59:59.000Z

    The power spectrum of number density perturbations of free electrons is obtained for the epoch of cosmological recombination of hydrogen. It is shown that amplitude of the electron perturbations power spectrum of scales larger than acoustic horizon exceeds by factor of 17 the amplitude of baryon matter density ones (atoms and ions of hydrogen and helium). In the range of the first and second acoustic peaks such relation is 18, in the range of the third one 16. The dependence of such relations on cosmological parameters is analysed too.

  13. Exact Near-Onset Analysis of the Spin-Density-Wave Instability in Ferromagnetic Superconductors - the Linearly Polarized State

    E-Print Network [OSTI]

    Hu, Chia-Ren.

    1984-01-01T23:59:59.000Z

    PHYSICAL REVIEW 8 VOLUME 30, NUMBER 5 1 SEPTEMBER 1984 Exact near-onset analysis of the spin-density-wave instability in ferromagnetic superconductors: The linearly polarized state Chia-Ren Hu Department ofPhysics, Texas Ad'cM Uniuersity..., College Station, Texas 77843 (Received 29 August 1983) Using an approach similar to Abvikosov's theory of the vortex state near H, 2, we have performed an exact, near-onset analysis of a spin-density-wave instability leading to the "linearly polarized...

  14. A Case Study of Wave Power Integration into the Ucluelet Area Electrical Grid Louise Anne St.Germain

    E-Print Network [OSTI]

    Victoria, University of

    as a renewable energy resource on Vancouver Island, specifically in the Tofino/Ucluelet area. A model of a waveA Case Study of Wave Power Integration into the Ucluelet Area Electrical Grid by Louise Anne St of wave power projects on Vancouver Island. Supervisors: Dr. Andrew Rowe, (Department of Mechanical

  15. Power Densities Using Different Cathode Catalysts (Pt and CoTMPP)

    E-Print Network [OSTI]

    that the maximum power achieved using ferricyanide ion as oxidant in the cathode chamber was 50-80% greater than and PTFE) in Single Chamber Microbial Fuel Cells S H A O A N C H E N G , H O N G L I U , A N D B R U C E catalysts and binders were examined for their effect on power densities in single chamber, air

  16. Development of frequency modulated continuous wave reflectometer for electron density profile measurement on the HL-2A tokamak

    SciTech Connect (OSTI)

    Zhong, W. L., E-mail: zhongwl@swip.ac.cn; Shi, Z. B.; Liu, Z. T.; Chen, W.; Jiang, M.; Li, J.; Cui, Z. Y.; Song, X. M.; Chen, L. Y.; Ding, X. T.; Liu, Yi; Yan, L. W.; Yang, Q. W.; Duan, X. R. [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China)] [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China); Huang, X. L. [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China) [Southwestern Institute of Physics, P.O. Box 432, Chengdu 610041 (China); Department of Fusion Science, Graduate University for Advanced Studies, Toki 509-5292 (Japan); Zou, X. L. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)] [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France)

    2014-01-15T23:59:59.000Z

    The frequency modulated continuous wave reflectometer was developed for the first time on the HL-2A tokamak. The system utilizes a voltage controlled oscillator and an active multiplier for broadband coverage and detects as heterodyne mode. Three reflectometers have been installed and operated in extraordinary mode polarization on HL-2A to measure density profiles at low field side, covering the Q-band (33–50 GHz), V-band (50–75 GHz), and W-band (75–110 GHz). For density profile reconstruction from the phase shift of the probing wave, a corrected phase unwrapping method is introduced in this article. The effectiveness of the method is demonstrated. The density profile behavior of a fast plasma event is presented and it demonstrates the capability of the reflectometer. These diagnostics will be contributed to the routine density profile measurements and the plasma physics study on HL-2A.

  17. High Power Superconducting Continuous Wave Linacs for Protons...

    Office of Science (SC) Website

    research, national security, therapeutic isotopes and transmutation of spent nuclear fuel Argonne National Laboratory has been working on research and development of high power...

  18. High-Efficiency and High-Power CMOS Power Amplifiers for Millimeter-Wave Applications /

    E-Print Network [OSTI]

    Agah, Amir

    2013-01-01T23:59:59.000Z

    K. Han, “W-band, 5W Solid-State Power Amplifier/Combiner,”materials have made high-power solid-state power amplifiersCMOS RF power amplifier for GSM-EDGE,” IEEE J. Solid-State

  19. High Performance Circuits for Power Management and Millimeter Wave Applications

    E-Print Network [OSTI]

    Amer, Ahmed 1979-

    2012-01-23T23:59:59.000Z

    to achieve the required goals in terms of small silicon area and power consumption while at the same time achieve high performance. Four key building blocks in power management and a switchable harmonic mixer with pre-amplifier and poly-phase generator as a...

  20. 2012 Jonathan G. Lange IMPROVING LITHIUM-ION BATTERY POWER AND ENERGY DENSITIES USING

    E-Print Network [OSTI]

    Braun, Paul

    1 ©2012 Jonathan G. Lange #12;1 IMPROVING LITHIUM-ION BATTERY POWER AND ENERGY DENSITIES USING ABSTRACT Lithium-ion batteries are commonly used as energy storage devices in a variety of applications. The cathode architectures and materials have a large influence on the performance of lithium-ion batteries

  1. Ultralow-power local laser control of the dimer density in alkali-metal vapors

    E-Print Network [OSTI]

    Jha, Pankaj K; Yi, Zhenhuan; Yuan, Luqi; Sautenkov, Vladimir A; Rostovtsev, Yuri V; Welch, George R; Zheltikov, Aleksei M; Scully, Marlan O

    2011-01-01T23:59:59.000Z

    Ultralow-power diode-laser radiation is employed to induce photodesorption of cesium from a partially transparent thin-film cesium adsorbate on a solid surface. Using resonant Raman spectroscopy, we demonstrate that this photodesorption process enables an accurate local optical control of the density of dimer molecules in alkali-metal vapors.

  2. Vacuum behaviors around rarefaction waves to 1D compressible Navier-Stokes equations with density-dependent viscosity

    E-Print Network [OSTI]

    Quansen Jiu; Yi Wang; Zhouping Xin

    2011-09-05T23:59:59.000Z

    In this paper, we study the large time asymptotic behavior toward rarefaction waves for solutions to the 1-dimensional compressible Navier-Stokes equations with density-dependent viscosities for general initial data whose far fields are connected by a rarefaction wave to the corresponding Euler equations with one end state being vacuum. First, a global-in-time weak solution around the rarefaction wave is constructed by approximating the system and regularizing the initial data with general perturbations, and some a priori uniform-in-time estimates for the energy and entropy are obtained. Then it is shown that the density of any weak solution satisfying the natural energy and entropy estimates will converge to the rarefaction wave connected to vacuum with arbitrary strength in super-norm time-asymptotically. Our results imply, in particular, that the initial vacuum at far fields will remain for all the time which are in contrast to the case of non-vacuum rarefaction waves studied in \\cite{JWX} where all the possible vacuum states will vanish in finite time. Finally, it is proved that the weak solution becomes regular away from the vacuum region of the rarefaction wave.

  3. Tunneling density of states of high Tc superconductors d-wave BCS model vs. SU(2) slave boson model

    E-Print Network [OSTI]

    Wen, Xiao-Gang

    Tunneling density of states of high Tc superconductors d-wave BCS model vs. SU(2) slave boson model conductance curves in the superconducting state at zero temperature. Comparing the two results obtained via Tunneling spectroscopy has been one of the funda- mental tools in studying the superconducting state

  4. On the breaking of a plasma wave in a thermal plasma. I. The structure of the density singularity

    SciTech Connect (OSTI)

    Bulanov, Sergei V.; Esirkepov, Timur Zh.; Kando, Masaki; Koga, James K.; Pirozhkov, Alexander S.; Nakamura, Tatsufumi [QuBS, Japan Atomic Energy Agency, 1-8-7 Umemidai, Kizugawa, Kyoto 619-0215 (Japan); Bulanov, Stepan S. [University of California, Berkeley, California 94720 (United States); Schroeder, Carl B.; Esarey, Eric [Lawrence Berkeley National Laboratory, Berkeley, California 94720 (United States); Califano, Francesco; Pegoraro, Francesco [Physics Department, University of Pisa, Pisa 56127 (Italy)

    2012-11-15T23:59:59.000Z

    The structure of the singularity that is formed in a relativistically large amplitude plasma wave close to the wave breaking limit is found by using a simple waterbag electron distribution function. The electron density distribution in the breaking wave has a typical 'peakon' form. The maximum value of the electric field in a thermal breaking plasma is obtained and compared to the cold plasma limit. The results of computer simulations for different initial electron distribution functions are in agreement with the theoretical conclusions. The after-wavebreak regime is then examined, and a semi-analytical model of the density evolution is constructed. Finally the results of two dimensional particle in cell simulations for different initial electron distribution functions are compared, and the role of thermal effects in enhancing particle injection is noted.

  5. Estimation of Heavy Ion Densities From Linearly Polarized EMIC Waves At Earth

    SciTech Connect (OSTI)

    Kim, Eun-Hwa; Johnson, Jay R.; Lee, Dong-Hun

    2014-02-24T23:59:59.000Z

    Linearly polarized EMIC waves are expected to concentrate at the location where their wave frequency satisfies the ion-ion hybrid (IIH) resonance condition as the result of a mode conversion process. In this letter, we evaluate absorption coefficients at the IIH resonance in the Earth geosynchronous orbit for variable concentrations of helium and azimuthal and field-aligned wave numbers in dipole magnetic field. Although wave absorption occurs for a wide range of heavy ion concentration, it only occurs for a limited range of azimuthal and field-aligned wave numbers such that the IIH resonance frequency is close to, but not exactly the same as the crossover frequency. Our results suggest that, at L = 6.6, linearly polarized EMIC waves can be generated via mode conversion from the compressional waves near the crossover frequency. Consequently, the heavy ion concentration ratio can be estimated from observations of externally generated EMIC waves that have polarization.

  6. High power water load for microwave and millimeter-wave radio frequency sources

    DOE Patents [OSTI]

    Ives, R. Lawrence (Saratoga, CA); Mizuhara, Yosuke M. (Palo Alto, CA); Schumacher, Richard V. (Sunnyvale, CA); Pendleton, Rand P. (Saratoga, CA)

    1999-01-01T23:59:59.000Z

    A high power water load for microwave and millimeter wave radio frequency sources has a front wall including an input port for the application of RF power, a cylindrical dissipation cavity lined with a dissipating material having a thickness which varies with depth, and a rear wall including a rotating reflector for the reflection of wave energy inside the cylindrical cavity. The dissipation cavity includes a water jacket for removal of heat generated by the absorptive material coating the dissipation cavity, and this absorptive material has a thickness which is greater near the front wall than near the rear wall. Waves entering the cavity reflect from the rotating reflector, impinging and reflecting multiple times on the absorptive coating of the dissipation cavity, dissipating equal amounts of power on each internal reflection.

  7. Two-dimensional AXUV-based radiated power density diagnostics on NSTX-U

    SciTech Connect (OSTI)

    Faust, I.; Parker, R. R. [MIT - Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Delgado-Aparicio, L.; Bell, R. E.; Diallo, A.; Gerhardt, S. P.; LeBlanc, B.; Kozub, T. A. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States); Tritz, K. [The Johns Hopkins University, Baltimore, Maryland 21209 (United States); Stratton, B. C. [MIT - Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States)

    2014-11-15T23:59:59.000Z

    A new set of radiated-power-density diagnostics for the National Spherical Torus Experiment Upgrade (NSTX-U) tokamak have been designed to measure the two-dimensional poloidal structure of the total photon emissivity profile in order to perform power balance, impurity transport, and magnetohydrodynamic studies. Multiple AXUV-diode based pinhole cameras will be installed in the same toroidal angle at various poloidal locations. The local emissivity will be obtained from several types of tomographic reconstructions. The layout and response expected for the new radially viewing poloidal arrays will be shown for different impurity concentrations to characterize the diagnostic sensitivity. The radiated power profile inverted from the array data will also be used for estimates of power losses during transitions from various divertor configurations in NSTX-U. The effect of in-out and top/bottom asymmetries in the core radiation from high-Z impurities will be addressed.

  8. Journal of Power Sources 153 (2006) 6875 Numerical study of a flat-tube high power density solid oxide fuel cell

    E-Print Network [OSTI]

    2006-01-01T23:59:59.000Z

    power density (HPD) solid oxide fuel cell (SOFC) is a geometry based on a tubular type SOFC: Flat-tube; High power density (HPD); Solid oxide fuel cell (SOFC); Simulation; Performance; Optimization 1. Introduction A solid oxide fuel cell (SOFC), like any other fuel cell, produces electrical

  9. High excitation power photoluminescence studies of ultra-low density GaAs quantum dots

    SciTech Connect (OSTI)

    Sonnenberg, D.; Graf, A.; Paulava, V.; Heyn, Ch.; Hansen, W. [Institut für Angewandte Physik und Zentrum für Mikrostrukturforschung, Universität Hamburg, Jungiusstr. 11, 20355 Hamburg (Germany)

    2013-12-04T23:59:59.000Z

    We fabricate GaAs epitaxial quantum dots (QDs) by filling of self-organized nanoholes in AlGaAs. The QDs are fabricated under optimized process conditions and have ultra-low density in the 10{sup 6} cm{sup ?2} regime. At low excitation power the optical emission of single QDs exhibit sharp excitonic lines, which are attributed to the recombination of excitonic and biexcitonic states. High excitation power measurements reveal surprisingly broad emission lines from at least six QD shell states.

  10. Wave-actuated power take-off device for electricity generation

    SciTech Connect (OSTI)

    Chertok, Allan

    2013-01-31T23:59:59.000Z

    Since 2008, Resolute Marine Energy, Inc. (RME) has been engaged in the development of a rigidly moored shallow-water point absorber wave energy converter, the "3D-WEC". RME anticipated that the 3D-WEC configuration with a fully buoyant point absorber buoy coupled to three power take off (PTO) units by a tripod array of tethers would achieve higher power capture than a more conventional 1-D configuration with a single tether and PTO. The investigation conducted under this program and documented herein addressed the following principal research question regarding RME'Â?Â?s power take off (PTO) concept for its 3D-WEC: Is RME's winch-driven generator PTO concept, previously implemented at sub-scale and tested at the Ohmsett wave tank facility, scalable in a cost-effective manner to significant power levels Â?Â?e.g., 10 to 100kW?

  11. A High Power-Density Mediator-Free Microfluidic Biophotovoltaic Device for Cyanobacterial Cells

    E-Print Network [OSTI]

    Bombelli, Paolo; Herling, Therese W; Howe, Christopher J; Knowles, Tuomas P J

    2014-01-01T23:59:59.000Z

    Biophotovoltaics has emerged as a promising technology for generating renewable energy since it relies on living organisms as inexpensive, self-repairing and readily available catalysts to produce electricity from an abundant resource - sunlight. The efficiency of biophotovoltaic cells, however, has remained significantly lower than that achievable through synthetic materials. Here, we devise a platform to harness the large power densities afforded by miniaturised geometries. To this effect, we have developed a soft-lithography approach for the fabrication of microfluidic biophotovoltaic devices that do not require membranes or mediators. Synechocystis sp. PCC 6803 cells were injected and allowed to settle on the anode, permitting the physical proximity between cells and electrode required for mediator-free operation. We demonstrate power densities of above 100 mW/m2 for a chlorophyll concentration of 100 {\\mu}M under white light, a high value for biophotovoltaic devices without extrinsic supply of additional...

  12. Performance Optimization of Battery-Super Capacitor Hybrid System Electrochemical capacitors (ultracapacitors) offer high power density when compared to battery

    E-Print Network [OSTI]

    Popov, Branko N.

    Performance Optimization of Battery-Super Capacitor Hybrid System Electrochemical capacitors a decreased value of power and energy densities for the hybrid system. Figure 1shows the fractional capacity (ultracapacitors) offer high power density when compared to battery systems and also have a relatively large energy

  13. Decommissioning nuclear power plants - the wave of the future

    SciTech Connect (OSTI)

    Griggs, F.S. Jr. [Raytheon Engineers and Contractors, Cumberland City, TN (United States)

    1994-12-31T23:59:59.000Z

    The paper discusses the project controls developed in the decommissioning of a nuclear power plant. Considerations are given to the contaminated piping and equipment that have to be removed and the spent and used fuel that has to be disposed of. The storage issue is of primary concern here. The cost control aspects and the dynamics of decommissioning are discussed. The effects of decommissioning laws on the construction and engineering firms are mentioned. 5 refs.

  14. An innovative demonstration of high power density in a compact MHD (magnetohydrodynamic) generator

    SciTech Connect (OSTI)

    Schmidt, H.J.; Lineberry, J.T.; Chapman, J.N.

    1990-06-01T23:59:59.000Z

    The present program was conducted by the University of Tennessee Space Institute (UTSI). It was by its nature a high risk experimental program to demonstrate the feasibility of high power density operation in a laboratory scale combustion driven MHD generator. Maximization of specific energy was not a consideration for the present program, but the results have implications in this regard by virtue of high energy fuel used. The power density is the ratio of the electrical energy output to the internal volume of the generator channel. The MHD process is a volumetric process and the power density is therefore a direct measure of the compactness of the system. Specific energy, is the ratio of the electrical energy output to consumable energy used for its production. The two parameters are conceptually interrelated. To achieve high power density and implied commensurate low system volume and weight, it was necessary to use an energetic fuel. The high energy fuel of choice was a mixture of powdered aluminum and carbon seeded with potassium carbonate and burned with gaseous oxygen. The solid fuel was burned in a hybrid combustion scheme wherein the fuel was cast within a cylindrical combustor in analogy with a solid propellant rocket motor. Experimental data is limited to gross channel output current and voltage, magnetic field strength, fuel and oxidizer flow rates, flow train external temperatures and combustor pressure. Similarly, while instantaneous oxidizer flow rates were measured, only average fuel consumption based on pre and post test component weights and dimensions was possible. 4 refs., 60 figs., 9 tabs.

  15. Inflation that runs naturally: Gravitational waves and suppression of power at large and small scales

    E-Print Network [OSTI]

    Quinn E. Minor; Manoj Kaplinghat

    2015-03-08T23:59:59.000Z

    We point out three correlated predictions of the axion monodromy inflation model: large amplitude of gravitational waves, suppression of power on horizon scales and on scales relevant for the formation of dwarf galaxies. While these predictions are likely generic to models with oscillations in the inflaton potential, the axion monodromy model naturally accommodates the required running spectral index through Planck-scale corrections to the inflaton potential. Applying this model to a combined data set of Planck, ACT, SPT, and WMAP low-$\\ell$ polarization cosmic microwave background (CMB) data, we find a best-fit tensor-to-scalar ratio $r_{0.05} = 0.07^{+0.05}_{-0.04}$ due to gravitational waves, which may have been observed by the BICEP2 experiment. Despite the contribution of gravitational waves, the total power on large scales (CMB power spectrum at low multipoles) is lower than the standard $\\Lambda$CDM cosmology with a power-law spectrum of initial perturbations and no gravitational waves, thus mitigating some of the tension on large scales. There is also a reduction in the matter power spectrum of 20-30\\% at scales corresponding to $k = 10~{\\rm Mpc}^{-1}$, which are relevant for dwarf galaxy formation. This will alleviate some of the unsolved small-scale structure problems in the standard $\\Lambda$CDM cosmology. The inferred matter power spectrum is also found to be consistent with recent Lyman-$\\alpha$ forest data, which is in tension with the Planck-favored $\\Lambda$CDM model with power-law primordial power spectrum.

  16. New Wave Power Project In Oregon | Department of Energy

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

    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 DataDepartment of Energy Your Density Isn'tOrigin of Contamination in Many DevilsForumEngines |New Technology forDepartment ofNew Voices

  17. Abstract This article will begin by presenting two power take-off (PTO) technologies for the SEAREV wave energy

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    for the SEAREV wave energy converter (WEC) followed by the design methodology applied to electromagnetic with the SEAREV WEC before discussing the two conversion technologies intended to transform wave energy, including one featuring power leveling. Index Terms ­ wave energy conversion - electromagnetic generator

  18. Long-range propagation of ocean waves

    E-Print Network [OSTI]

    Young, William R.

    hours. Friday, February 22, 2013 #12;OceanPowerTechnologies A 103 foot long, 260ton buoy being tested #12;Wave Power? PelamisWavePower With T=10sec and a = 1 meter, the energy flux is 40kW/meter. An average 40kW/meter of wave power is typical of good sites. Energy Flux = cg × Energy Density = g2 Ta2 8

  19. Particle-Number Restoration within the Energy Density Functional formalism: Nonviability of terms depending on noninteger powers of the density matrices

    E-Print Network [OSTI]

    T. Duguet; M. Bender; K. Bennaceur; D. Lacroix; T. Lesinski

    2009-03-04T23:59:59.000Z

    We discuss the origin of pathological behaviors that have been recently identified in particle-number-restoration calculations performed within the nuclear energy density functional framework. A regularization method that removes the problematic terms from the multi-reference energy density functional and which applies (i) to any symmetry restoration- and/or generator-coordinate-method-based configuration mixing calculation and (ii) to energy density functionals depending only on integer powers of the density matrices, was proposed in [D. Lacroix, T. Duguet, M. Bender, arXiv:0809.2041] and implemented for particle-number restoration calculations in [M. Bender, T. Duguet, D. Lacroix, arXiv:0809.2045]. In the present paper, we address the viability of non-integer powers of the density matrices in the nuclear energy density functional. Our discussion builds upon the analysis already carried out in [J. Dobaczewski \\emph{et al.}, Phys. Rev. C \\textbf{76}, 054315 (2007)]. First, we propose to reduce the pathological nature of terms depending on a non-integer power of the density matrices by regularizing the fraction that relates to the integer part of the exponent using the method proposed in [D. Lacroix, T. Duguet, M. Bender, arXiv:0809.2041]. Then, we discuss the spurious features brought about by the remaining fractional power. Finally, we conclude that non-integer powers of the density matrices are not viable and should be avoided in the first place when constructing nuclear energy density functionals that are eventually meant to be used in multi-reference calculations.

  20. Calling All Coders: Help Advance America's Wave Power Industry | Department

    Energy Savers [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 onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directed off Energy.gov. Are you sure you want toworldPower 2010 1AAcquisition »Department link to

  1. Experimental Investigation of Non-Thermal Electric Fields and Plasma Waves in Pulsed-Power Plasmas

    E-Print Network [OSTI]

    -field-plasma interaction, particle accelera- tion, growth of instabilities and plasma waves. As yet, to the hest of our and the properties of plasmas under high-power pulses at the nanosecond time scale. The method is based on resonant in a coaxial-pulsed-plasma configura- tion. The plasma is doped with a laser-produced lithium heam, fol- lowed

  2. High-resolution Tangential AXUV Arrays for Radiated Power Density Measurements on NSTX-U

    SciTech Connect (OSTI)

    Delgado-Aparicio, L [PPPL; Bell, R E [PPPL; Faust, I [MIT; Tritz, K [The Johns Hopkins University, Baltimore, MD, 21209, USA; Diallo, A [PPPL; Gerhardt, S P [PPPL; Kozub, T A [PPPL; LeBlanc, B P [PPPL; Stratton, B C [PPPL

    2014-07-01T23:59:59.000Z

    Precise measurements of the local radiated power density and total radiated power are a matter of the uttermost importance for understanding the onset of impurity-induced instabilities and the study of particle and heat transport. Accounting of power balance is also needed for the understanding the physics of various divertor con#12;gurations for present and future high-power fusion devices. Poloidal asymmetries in the impurity density can result from high Mach numbers and can impact the assessment of their flux-surface-average and hence vary the estimates of P[sub]rad (r, t) and (Z[sub]eff); the latter is used in the calculation of the neoclassical conductivity and the interpretation of non-inductive and inductive current fractions. To this end, the bolometric diagnostic in NSTX-U will be upgraded, enhancing the midplane coverage and radial resolution with two tangential views, and adding a new set of poloidally-viewing arrays to measure the 2D radiation distribution. These systems are designed to contribute to the near- and long-term highest priority research goals for NSTX-U which will integrate non-inductive operation at reduced collisionality, with high-pressure, long energy-confinement-times and a divertor solution with metal walls.

  3. Off-center HII regions in power-law density distributions

    E-Print Network [OSTI]

    S. J. Arthur

    2007-05-05T23:59:59.000Z

    The expansion of ionization fronts in uniform and spherically symmetric power-law density distributions is a well-studied topic. However, in many situations, such as a star formed at the edge of a molecular cloud core, an offset power-law density distribution would be more appropriate. In this paper a few of the main issues of the formation and expansion of HII regions in such media are outlined and results are presented for the particular cases where the underlying power laws are 1/r^2 and 1/r^3. A simple criterion is developed for determining whether the initial photoionized region will be unbounded, which depends on the power-law exponent and the ratio of the equivalent Stroemgren radius produced by the star in a uniform medium to the stellar offset distance. In the expansion stage, the ionized volumes will eventually become unbounded unless pressure balance with the external medium is reached before the ionization front velocity becomes supersonic with respect to the ionized gas.

  4. Quasiparticle interference, quasiparticle interactions, and the origin of the charge density wave in 2H-NbSe?

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

    Arguello, C. J.; Valla, T.; Rosenthal, E. P.; Andrade, E. F.; Jin, W.; Yeh, P. C.; Zaki, N.; Jia, S.; Cava, R. J.; Fernandes, R. M.; et al

    2015-01-01T23:59:59.000Z

    We show that a small number of intentionally introduced defects can be used as a spectroscopic tool to amplify quasiparticle interference in 2H-NbSe?, that we measure by scanning tunneling spectroscopic imaging. We show from the momentum and energy dependence of the quasiparticle interference that Fermi surface nesting is inconsequential to charge density wave formation in 2H-NbSe?. We demonstrate that by combining quasiparticle interference data with additional knowledge of the quasiparticle band structure from angle resolved photoemission measurements, one can extract the wavevector and energy dependence of the important electronic scattering processes thereby obtaining direct information both about the fermiology andmore »the interactions. In 2H-NbSe?, we use this combination to show that the important near-Fermi-surface electronic physics is dominated by the coupling of the quasiparticles to soft mode phonons at a wave vector different from the CDW ordering wave vector.« less

  5. Quasiparticle interference, quasiparticle interactions, and the origin of the charge density wave in 2H-NbSe?

    SciTech Connect (OSTI)

    Arguello, C. J. [Columbia Univ., New York, NY (United States); Valla, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Rosenthal, E. P. [Columbia Univ., New York, NY (United States); Andrade, E. F. [Columbia Univ., New York, NY (United States); Jin, W. [Columbia Univ., New York, NY (United States); Yeh, P. C. [Columbia Univ., New York, NY (United States); Zaki, N. [Columbia Univ., New York, NY (United States); Jia, S. [Princeton Univ., NJ (United States); Cava, R. J. [Princeton Univ., NJ (United States); Fernandes, R. M. [Univ., of Minnesota, Minneapolis, MN (United States); Millis, A. J. [Columbia Univ., New York, NY (United States); Osgood, Jr., R. M. [Columbia Univ., New York, NY (United States); Princeton Univ., Princeton, NJ (United States); Pasupathy, A. N. [Columbia Univ., New York, NY (United States)

    2015-01-01T23:59:59.000Z

    We show that a small number of intentionally introduced defects can be used as a spectroscopic tool to amplify quasiparticle interference in 2H-NbSe?, that we measure by scanning tunneling spectroscopic imaging. We show from the momentum and energy dependence of the quasiparticle interference that Fermi surface nesting is inconsequential to charge density wave formation in 2H-NbSe?. We demonstrate that by combining quasiparticle interference data with additional knowledge of the quasiparticle band structure from angle resolved photoemission measurements, one can extract the wavevector and energy dependence of the important electronic scattering processes thereby obtaining direct information both about the fermiology and the interactions. In 2H-NbSe?, we use this combination to show that the important near-Fermi-surface electronic physics is dominated by the coupling of the quasiparticles to soft mode phonons at a wave vector different from the CDW ordering wave vector.

  6. Quasiparticle interference, quasiparticle interactions, and the origin of the charge density wave in 2H-NbSe?

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

    Arguello, C. J. [Columbia Univ., New York, NY (United States); Valla, T. [Brookhaven National Lab. (BNL), Upton, NY (United States); Rosenthal, E. P. [Columbia Univ., New York, NY (United States); Andrade, E. F. [Columbia Univ., New York, NY (United States); Jin, W. [Columbia Univ., New York, NY (United States); Yeh, P. C. [Columbia Univ., New York, NY (United States); Zaki, N. [Columbia Univ., New York, NY (United States); Jia, S. [Princeton Univ., NJ (United States); Cava, R. J. [Princeton Univ., NJ (United States); Fernandes, R. M. [Univ., of Minnesota, Minneapolis, MN (United States); Millis, A. J. [Columbia Univ., New York, NY (United States); Osgood, Jr., R. M. [Columbia Univ., New York, NY (United States); Princeton Univ., Princeton, NJ (United States); Pasupathy, A. N. [Columbia Univ., New York, NY (United States)

    2015-01-01T23:59:59.000Z

    We show that a small number of intentionally introduced defects can be used as a spectroscopic tool to amplify quasiparticle interference in 2H-NbSe?, that we measure by scanning tunneling spectroscopic imaging. We show from the momentum and energy dependence of the quasiparticle interference that Fermi surface nesting is inconsequential to charge density wave formation in 2H-NbSe?. We demonstrate that by combining quasiparticle interference data with additional knowledge of the quasiparticle band structure from angle resolved photoemission measurements, one can extract the wavevector and energy dependence of the important electronic scattering processes thereby obtaining direct information both about the fermiology and the interactions. In 2H-NbSe?, we use this combination to show that the important near-Fermi-surface electronic physics is dominated by the coupling of the quasiparticles to soft mode phonons at a wave vector different from the CDW ordering wave vector.

  7. Investigation of an improved relativistic backward wave oscillator in efficiency and power capacity

    SciTech Connect (OSTI)

    Song, W.; Chen, C. H.; Sun, J.; Zhang, X. W.; Shao, H.; Song, Z. M.; Huo, S. F.; Shi, Y. C.; Li, X. Z. [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an, Shaanxi 710024 (China)

    2012-10-15T23:59:59.000Z

    Investigation of relativistic backward wave oscillator with high efficiency and power capacity is presented in this paper. To obtain high power and high efficiency, a TM{sub 021} mode resonant reflector is used to reduce the pulse shortening and increase power capacity to about 1.7 times. Meanwhile, an extraction cavity at the end of slow wave structure is employed to improve the efficiency from less than 30% to over 40%, through the beam-wave interaction intensification and better energy conversion from modulated electron beam to the electromagnetic field. Consistent with the numerical results, microwave with a power of 3.2 GW, a frequency of 9.75 GHz, and a pulse width of 27 ns was obtained in the high power microwave generation experiment, where the electron beam energy was configured to be {approx}910 kV and its current to be {approx}8.6 kA. The efficiency of the RBWO exceeds 40% at a voltage range of 870 kV-1000 kV.

  8. Experimental Investigation of the Power Generation Performance of Floating-Point Absorber Wave Energy Systems: Preprint

    SciTech Connect (OSTI)

    Li, Y.; Yu, Y.; Epler, J.; Previsic, M.

    2012-04-01T23:59:59.000Z

    The extraction of energy from ocean waves has gained interest in recent years. The floating-point absorber (FPA) is one of the most promising devices among a wide variety of wave energy conversion technologies. Early theoretical studies mainly focused on understanding the hydrodynamics of the system and on predicting the maximum power that could be extracted by a heaving body. These studies evolve from the investigation of floating-body interactions in offshore engineering and naval architecture disciplines. To our best knowledge, no systematic study has been reported about the investigation of the power generation performance of an FPA with a close-to-commercial design. A series of experimental tests was conducted to investigate the power extraction performance of an FPA system.

  9. Generation of potential/surface density pairs in flat disks Power law distributions

    E-Print Network [OSTI]

    J. -M. Hure; D. Pelat; A. Pierens

    2007-06-25T23:59:59.000Z

    We report a simple method to generate potential/surface density pairs in flat axially symmetric finite size disks. Potential/surface density pairs consist of a ``homogeneous'' pair (a closed form expression) corresponding to a uniform disk, and a ``residual'' pair. This residual component is converted into an infinite series of integrals over the radial extent of the disk. For a certain class of surface density distributions (like power laws of the radius), this series is fully analytical. The extraction of the homogeneous pair is equivalent to a convergence acceleration technique, in a matematical sense. In the case of power law distributions, the convergence rate of the residual series is shown to be cubic inside the source. As a consequence, very accurate potential values are obtained by low order truncation of the series. At zero order, relative errors on potential values do not exceed a few percent typically, and scale with the order N of truncation as 1/N**3. This method is superior to the classical multipole expansion whose very slow convergence is often critical for most practical applications.

  10. Charge-density-wave origin of cuprate checkerboard visualized by scanning tunnelling microscopy

    E-Print Network [OSTI]

    Wise, W. D.

    One of the main challenges in understanding high-Tc superconductivity is to disentangle the rich variety of states of matter that may coexist, cooperate or compete with d-wave superconductivity. At centre stage is the ...

  11. Possible Zero-Flux Transport induced by Density Waves in a Tube filled with Solid Helium

    E-Print Network [OSTI]

    Kwang-Hua W. Chu

    2006-11-07T23:59:59.000Z

    Macroscopic derivation of the entrainment in a supersolid cylinder induced by a surface elastic wave (of small amplitude) propagating along the flexible interface is conducted by considering the nonlinear coupling between the interface and the rarefaction effect. We obtain the critical bounds for zero-volume-flow-rate states corresponding to specific rarefaction measure and wave number which is relevant to the rather small critical velocity or disappearance of supersolid flows reported by Rittner and Reppy.

  12. Power densities for two-step gamma-ray transitions from isomeric states

    E-Print Network [OSTI]

    Silviu Olariu; Agata Olariu

    1999-08-19T23:59:59.000Z

    We have calculated the incident photon power density P_2 for which the two-step induced emission rate from an isomeric nucleus becomes equal to the natural isomeric decay rate. We have analyzed two-step transitions for isomeric nuclei with a half-life greater than 10 min, for which there is an intermediate state of known energy, spin and half-life, for which the intermediate state is connected by a known gamma-ray transition to the isomeric state and to at least another intermediate state, and for which the relative intensities of the transitions to lower states are known. For the isomeric nucleus 166m-Ho, which has a 1200 y isomeric state at 5.98 keV, we have found a value of P_2=6.3 x 10^7 W cm^{-2}, the intermediate state being the 263.8 keV level. We have found power densities P_2 of the order of 10^{10} W cm^{-2} for several other isomeric nuclei.

  13. Power Smoothing and Limitation Control of a PMSG-Based Marine Current Turbine under Swell Waves

    E-Print Network [OSTI]

    Boyer, Edmond

    Power Smoothing and Limitation Control of a PMSG-Based Marine Current Turbine under Swell Waves la puissance maximale (MPPT) nécessiterait d'accélérer ou de décélérer fréquemment la turbine à par une turbine marine associée à un générateur synchrone à aimants permanents (GSAP). Un algorithme

  14. Experimental determination of radiated internal wave power without pressure field data

    SciTech Connect (OSTI)

    Lee, Frank M.; Morrison, P. J. [Physics Department and Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712–1192 (United States)] [Physics Department and Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712–1192 (United States); Paoletti, M. S.; Swinney, Harry L. [Physics Department, The University of Texas at Austin, Austin, Texas 78712–1192 (United States)] [Physics Department, The University of Texas at Austin, Austin, Texas 78712–1192 (United States)

    2014-04-15T23:59:59.000Z

    We present a method to determine, using only velocity field data, the time-averaged energy flux (J) and total radiated power P for two-dimensional internal gravity waves. Both (J) and P are determined from expressions involving only a scalar function, the stream function ?. We test the method using data from a direct numerical simulation for tidal flow of a stratified fluid past a knife edge. The results for the radiated internal wave power given by the stream function method agree to within 0.5% with results obtained using pressure and velocity data from the numerical simulation. The results for the radiated power computed from the stream function agree well with power computed from the velocity and pressure if the starting point for the stream function computation is on a solid boundary, but if a boundary point is not available, care must be taken to choose an appropriate starting point. We also test the stream function method by applying it to laboratory data for tidal flow past a knife edge, and the results are found to agree with the direct numerical simulation. The supplementary material includes a Matlab code with a graphical user interface that can be used to compute the energy flux and power from two-dimensional velocity field data.

  15. Power Density Spectra of Gamma-Ray Burst Light Curves: Implications on Theory and Observation

    E-Print Network [OSTI]

    Heon-Young Chang; Insu Yi

    2001-01-02T23:59:59.000Z

    We study the power density spectrum (PDS) of artificial light curves of observed gamma-ray bursts (GRBs). We investigate statistical properties of GRB light curves by comparing the reported characteristics in the PDSs of the observed GRBs with those that we model, and discuss implications on interpretations of the PDS analysis results. Results of PDS analysis of observed GRBs suggest that the averaged PDS of GRBs follows a power law over about two decades of frequency with the power law index, -5/3, and the distribution of individual power follows an exponential distribution. Though an attempt to identify the most sensitive physical parameter has been made on the basis of the internal shock model, we demonstrate that conclusions of this kind of approach should be derived with due care. It is indicative that the physical information extracted from the slope can be misleading. We show that the reported slope and the distribution can be reproduced by adjusting the sampling interval in the time domain for a given decaying timescale of individual pulse in a specific form of GRB light curves. In particular, given that the temporal feature is modeled by a two-sided exponential function, the power law behavior with the index of -5/3 and the exponential distribution of the observed PDS is recovered at the 64 ms trigger time scale when the decaying timescale of individual pulse is $\\sim 1$ second, provided that the pulse sharply rises. Another way of using the PDS analysis is an application of the same method to individual long bursts in order to examine a possible evolution of the decaying timescale in a single burst.

  16. A thermally self-sustained micro solid-oxide fuel-cell stack with high power density

    E-Print Network [OSTI]

    Haile, Sossina M.

    A thermally self-sustained micro solid-oxide fuel-cell stack with high power density Zongping Shao1 design challenges and cannot operate with hydrocarbon fuels of higher energy density. Solid-oxide fuel cells (SOFCs) enable direct use of higher hydrocarbons4­6 , but have not been seriously con- sidered

  17. Instability of low density supersonic waves of a viscous isentropic gas flow through a nozzle

    E-Print Network [OSTI]

    Liu, Weishi

    of isentropic compressible fluid through a narrow nozzle with variable cross-section area (see [1, 2, 3, 10, 11 flows through a nozzle with varying cross-section areas. The main result in this paper is, for small-section area a(x) is sufficiently small. T. P. Liu then focused on transonic waves of gas flow in a nozzle

  18. Progress at the interface of wave-function and density-functional theories

    SciTech Connect (OSTI)

    Gidopoulos, Nikitas I. [ISIS, Rutherford Appleton Laboratory, STFC, Didcot, OX11 0QX, Oxon (United Kingdom)

    2011-04-15T23:59:59.000Z

    The Kohn-Sham (KS) potential of density-functional theory (DFT) emerges as the minimizing effective potential in a variational scheme that does not involve fixing the unknown single-electron density. Using Rayleigh Schroedinger (RS) perturbation theory (PT), we construct ab initio approximations for the energy difference, the minimization of which determines the KS potential directly - thereby bypassing DFT's traditional algorithm to search for the density that minimizes the total energy. From second-order RS PT, we obtain variationally stable energy differences to be minimized, solving the severe problem of variational collapse of orbital-dependent exchange-correlation functionals based on second-order RS PT.

  19. Non-intrusive beam power monitor for high power pulsed or continuous wave lasers

    DOE Patents [OSTI]

    Hawsey, Robert A. (Oak Ridge, TN); Scudiere, Matthew B. (Oak Ridge, TN)

    1993-01-01T23:59:59.000Z

    A system and method for monitoring the output of a laser is provided in which the output of a photodiode disposed in the cavity of the laser is used to provide a correlated indication of the laser power. The photodiode is disposed out of the laser beam to view the extraneous light generated in the laser cavity whose intensity has been found to be a direct correlation of the laser beam output power level. Further, the system provides means for monitoring the phase of the laser output beam relative to a modulated control signal through the photodiode monitor.

  20. Ferroelectricity Induced by Acentric Spin-Density Waves in YMn{sub 2}O{sub 5}

    SciTech Connect (OSTI)

    Chapon, L.C. [ISIS Facility, Rutherford Appleton Laboratory-CCLRC, Chilton, Didcot, Oxfordshire, OX11 0QX (United Kingdom); Radaelli, P.G. [ISIS Facility, Rutherford Appleton Laboratory-CCLRC, Chilton, Didcot, Oxfordshire, OX11 0QX (United Kingdom); Department of Physics and Astronomy, University College London, Gower Street, London WC1E 6BT (United Kingdom); Blake, G.R. [ISIS Facility, Rutherford Appleton Laboratory-CCLRC, Chilton, Didcot, Oxfordshire, OX11 0QX (United Kingdom); Materials Science Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Park, S.; Cheong, S.-W. [Department of Physics and Astronomy, Rutgers University, Piscataway, New Jersey 08854 (United States)

    2006-03-10T23:59:59.000Z

    The commensurate and incommensurate magnetic structures of the magnetoelectric system YMn{sub 2}O{sub 5}, as determined from neutron diffraction, were found to be spin-density waves lacking a global center of symmetry. We propose a model, based on a simple magnetoelastic coupling to the lattice, which enables us to predict the polarization based entirely on the observed magnetic structure. Our data accurately reproduce the temperature dependence of the spontaneous polarization, particularly its sign reversal at the commensurate-incommensurate transition.

  1. Durability of Low Platinum Fuel Cells Operating at High Power Density

    SciTech Connect (OSTI)

    Polevaya, Olga [Nuvera Fuel Cells Inc.] [Nuvera Fuel Cells Inc.; Blanchet, Scott [Nuvera Fuel Cells Inc.] [Nuvera Fuel Cells Inc.; Ahluwalia, Rajesh [Argonne National Lab] [Argonne National Lab; Borup, Rod [Los-Alamos National Lab] [Los-Alamos National Lab; Mukundan, Rangachary [Los-Alamos National Lab] [Los-Alamos National Lab

    2014-03-19T23:59:59.000Z

    Understanding and improving the durability of cost-competitive fuel cell stacks is imperative to successful deployment of the technology. Stacks will need to operate well beyond today’s state-of-the-art rated power density with very low platinum loading in order to achieve the cost targets set forth by DOE ($15/kW) and ultimately be competitive with incumbent technologies. An accelerated cost-reduction path presented by Nuvera focused on substantially increasing power density to address non-PGM material costs as well as platinum. The study developed a practical understanding of the degradation mechanisms impacting durability of fuel cells with low platinum loading (?0.2mg/cm2) operating at high power density (?1.0W/cm2) and worked out approaches for improving the durability of low-loaded, high-power stack designs. Of specific interest is the impact of combining low platinum loading with high power density operation, as this offers the best chance of achieving long-term cost targets. A design-of-experiments approach was utilized to reveal and quantify the sensitivity of durability-critical material properties to high current density at two levels of platinum loading (the more conventional 0.45 mgPt.cm–1 and the much lower 0.2 mgPt.cm–2) across several cell architectures. We studied the relevance of selected component accelerated stress tests (AST) to fuel cell operation in power producing mode. New stress tests (NST) were designed to investigate the sensitivity to the addition of electrical current on the ASTs, along with combined humidity and load cycles and, eventually, relate to the combined city/highway drive cycle. Changes in the cathode electrochemical surface area (ECSA) and average oxygen partial pressure on the catalyst layer with aging under AST and NST protocols were compared based on the number of completed cycles. Studies showed elevated sensitivity of Pt growth to the potential limits and the initial particle size distribution. The ECSA loss was correlated with the upper potential limit in the cycle tests, although the performance degradation was found to be a strong function of initial Pt loading. A large fraction of the voltage degradation was found due to increased mass transfer overpotentials, especially in the lower Pt loading cells. Increased mass transfer overpotentials were responsible for a large fraction of the voltage degradation at high current densities. Analysis of the impedance and polarization data indicated O2 diffusion in the aged electrode ionomer to be the main source of the increased mass transfer overpotentials. Results from the experimental parametric studies were used to inform and calibrate newly developed durability model, simulating lifetime performance of the fuel cell under variety of load-cycle protocols, electrode loadings and throughout wide range of operating conditions, including elevated-to-3.0A/cm2 current densities. Complete durability model included several sub-models: platinum dissolution-and-growth as well as reaction-diffusion model of cathode electrode, applied sequentially to study the lifetime predictions of ECSA and polarization performance in the ASTs and NSTs. These models establish relations between changes in overpotentials, ECSA and oxygen mass transport in fuel cell cathodes. The model was calibrated using single cells with land-channel and open flowfield architectures. The model was validated against Nuvera Orion® (open flowfield) short stack data in the load cycle durability tests. The reaction-diffusion model was used to correlate the effective mass transfer coefficients for O2 diffusion in cathode ionomer and separately in gas pores with the operating conditions (pressure, temperature, gas velocity in flow field and current density), Pt loading, and ageing related growth in Pt particles and thinning of the electrode. Achievements of both modeling and experimental objectives were demonstrated in a full format, subscale stacks operating in a simulated but fully realistic ambient environment, using system-compatible operating protocols.

  2. Under consideration for publication in J. Fluid Mech. 1 Wave-power extraction by a compact array

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Under consideration for publication in J. Fluid Mech. 1 Wave-power extraction by a compact array of buoys X A V I E R G A R N A U D1 AND C H I A N G C. M E I2 1 Department of Aeronautics and Astronautics) The majority of existing single-unit devices for extracting power from sea-waves relies on resonance

  3. Gamma-ray burst prompt emission light curves and power density spectra in the ICMART model

    SciTech Connect (OSTI)

    Zhang, Bo [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Zhang, Bing, E-mail: bozhang@physics.unlv.edu, E-mail: zhang@physics.unlv.edu [Department of Physics and Astronomy, University of Nevada Las Vegas, Las Vegas, NV 89154 (United States)

    2014-02-20T23:59:59.000Z

    In this paper, we simulate the prompt emission light curves of gamma-ray bursts (GRBs) within the framework of the Internal-Collision-induced MAgnetic Reconnection and Turbulence (ICMART) model. This model applies to GRBs with a moderately high magnetization parameter ? in the emission region. We show that this model can produce highly variable light curves with both fast and slow components. The rapid variability is caused by many locally Doppler-boosted mini-emitters due to turbulent magnetic reconnection in a moderately high ? flow. The runaway growth and subsequent depletion of these mini-emitters as a function of time define a broad slow component for each ICMART event. A GRB light curve is usually composed of multiple ICMART events that are fundamentally driven by the erratic GRB central engine activity. Allowing variations of the model parameters, one is able to reproduce a variety of light curves and the power density spectra as observed.

  4. Gamma-Ray Burst Prompt Emission Light Curves and Power Density Spectra in the ICMART Model

    E-Print Network [OSTI]

    Zhang, Bo

    2013-01-01T23:59:59.000Z

    In this paper, we simulate the prompt emission light curves of gamma-ray bursts (GRBs) within the framework of the Internal-Collision-induced MAgnetic Reconnection and Turbulence (ICMART) model. This model applies to GRBs with a moderately-high magnetization parameter $\\sigma$ in the emission region. We show that this model can produce highly variable light curves with both fast and slow components. The rapid variability is caused by many locally Doppler-boosted mini-emitters due to turbulent magnetic reconnection in a moderately-high-$\\sigma$ flow. The run-away growth and subsequent depletion of these mini-emitters as a function time define a broad slow component for each ICMART event. A GRB light curve is usually composed of multiple ICMART events that are fundamentally driven by the erratic GRB central engine activity. Allowing variations of the model parameters, one is able to reproduce a variety of light curves and the power density spectra as observed.

  5. On-chip Sensing and Actuation Methods for Integrated Self-healing mm-Wave CMOS Power Amplifier

    E-Print Network [OSTI]

    Hajimiri, Ali

    GHz. The RF power sensors are designed to measure true input and output power in the presence of load and healing of a mm-Wave power amplifier. We demonstrate low insertion loss (0.4dB) RF sensors which measure true input and output power in presence of load variations and very low- headroom (10-30mV) DC sensors

  6. LOW-TEMPERATURE, ANODE-SUPPORTED HIGH POWER DENSITY SOLID OXIDE FUEL CELLS WITH NANOSTRUCTURED ELECTRODES

    SciTech Connect (OSTI)

    Anil V. Virkar

    2001-06-21T23:59:59.000Z

    A simple, approximate analysis of the effect of differing cathode and anode areas on the measurement of cell performance on anode-supported solid oxide fuel cells, wherein the cathode area is smaller than the anode area, is presented. It is shown that the effect of cathode area on cathode polarization, on electrolyte contribution, and on anode resistance, as normalized on the basis of the cathode area, is negligible. There is a small but measurable effect on anode polarization, which results from concentration polarization. Effectively, it is the result of a greater amount of fuel transported to the anode/electrolyte interface in cases wherein the anode area is larger than the cathode area. Experiments were performed on cells made with differing cathode areas and geometries. Cathodic and anodic overpotentials measured using reference electrodes, and the measured ohmic area specific resistances by current interruption, were in good agreement with expectations based on the analysis presented. At 800 C, the maximum power density measured with a cathode area of {approx}1.1 cm{sup 2} was {approx}1.65 W/cm{sup 2} compared to {approx}1.45 W/cm{sup 2} for cathode area of {approx}2 cm{sup 2}, for anode thickness of {approx}1.3 mm, with hydrogen as the fuel and air as the oxidant. At 750 C, the measured maximum power densities were {approx}1.3 W/cm{sup 2} for the cell with cathode area {approx}1.1 cm{sup 2}, and {approx}1.25 W/cm{sup 2} for the cell with cathode area {approx}2 cm{sup 2}.

  7. Minimizing lighting power density in office rooms equipped with Anidolic Daylighting Systems

    SciTech Connect (OSTI)

    Linhart, Friedrich; Scartezzini, Jean-Louis [Solar Energy and Building Physics Laboratory (LESO-PB), Ecole Polytechnique Federale de Lausanne (EPFL), 1015 Lausanne (Switzerland)

    2010-04-15T23:59:59.000Z

    Electric lighting is responsible for up to one third of an office building's electricity needs. Making daylight more available in office buildings can not only contribute to significant energy savings but also enhance the occupants' performance and wellbeing. Anidolic Daylighting Systems (ADS) are one type of very effective facade-integrated daylighting systems. All south-facing office rooms within the LESO solar experimental building in Lausanne (Switzerland) are equipped with a given type of ADS. A recent study has shown that these offices' occupants are highly satisfied with their lighting environment. The most energy-efficient south-facing offices have a lighting power density of less than 5W/m{sup 2}. The lighting situation within these ''best practice''-offices has been assessed using the lighting simulation software RELUX Vision. Because this lighting situation is very much appreciated by the occupants, it was used as a starting point for developing even more energy-efficient office lighting designs. Two new lighting designs, leading to lighting power densities of 3.9W/m{sup 2} and 3W/m{sup 2}, respectively, have been suggested and simulated with RELUX Vision. Simulation results have shown that the expected performances of these new systems are comparable to that of the current lighting installation within the ''best practice''-offices or even better. These simulation results have been confirmed during experiments on 20 human subjects in a test office room recently set up within the LESO building. This article gives engineers, architects and light planers valuable information and ideas on how to design energy-efficient and comfortable electric lighting systems in office rooms with abundant access to daylight. (author)

  8. Quantum Statistical Mechanics. I. Decoherence, Wave Function Collapse, and the von Neumann Density Matrix

    E-Print Network [OSTI]

    Phil Attard

    2013-11-25T23:59:59.000Z

    The probability operator is derived from first principles for an equilibrium quantum system. It is also shown that the superposition states collapse into a mixture of states giving the conventional von Neumann trace form for the quantum average. The mechanism for the collapse is found to be quite general: it results from the conservation law for a conserved, exchangeable variable (such as energy) and the entanglement of the total system wave function that necessarily follows. The relevance of the present results to the einselection mechanism for decoherence, to the quantum measurement problem, and to the classical nature of the macroscopic world are discussed.

  9. Tools for incorporating a D-wave contribution in Skyrme energy density functionals

    E-Print Network [OSTI]

    P. Becker; D. Davesne; J. Meyer; A. Pastore; J. Navarro

    2014-06-02T23:59:59.000Z

    The possibility of adding a D-wave term to the standard Skyrme effective interaction has been widely considered in the past. Such a term has been shown to appear in the next-to-next-to-leading order of the Skyrme pseudo-potential. The aim of the present article is to provide the necessary tools to incorporate this term in a fitting procedure: first, a mean-field equation written in spherical symmetry in order to describe spherical nuclei and second, the response function to detect unphysical instabilities. With these tools it will be possible to build a new fitting procedure to determine the coupling constants of the new functional.

  10. APEX and ALPS, high power density technology programs in the U.S.

    SciTech Connect (OSTI)

    Wong, C. [General Atomics, San Diego, CA (United States). Fusion Group; Berk, S. [Dept. of Energy, Washington, DC (United States). Office of Fusion Energy Sciences; Abdou, M. [Univ. of California, Los Angeles, CA (United States). School of Engineering and Applied Science; Mattas, R. [Argonne National Lab., IL (United States). Fusion Power Program

    1999-02-01T23:59:59.000Z

    In fiscal year (FY) 1998 two new fusion technology programs were initiated in the US, with the goal of making marked progress in the scientific understanding of technologies and materials required to withstand high plasma heat flux and neutron wall loads. APEX is exploring new and revolutionary concepts that can provide the capability to extract heat efficiently from a system with high neutron and surface heat loads while satisfying all the fusion power technology requirements and achieving maximum reliability, maintainability, safety, and environmental acceptability. ALPS program is evaluating advanced concepts including liquid surface limiters and divertors on the basis of such factors as their compatibility with fusion plasma, high power density handling capabilities, engineering feasibility, lifetime, safety and R and D requirements. The APEX and ALPS are three-year programs to specify requirements and evaluate criteria for revolutionary approaches in first wall, blanket and high heat flux component applications. Conceptual design and analysis of candidate concepts are being performed with the goal of selecting the most promising first wall, blanket and high heat flux component designs that will provide the technical basis for the initiation of a significant R and D effort beginning in FY2001. These programs are also considering opportunities for international collaborations.

  11. Enhanced modified faraday cup for determination of power density distribution of electron beams

    DOE Patents [OSTI]

    Elmer, John W. (Danville, CA); Teruya, Alan T. (Livermore, CA)

    2001-01-01T23:59:59.000Z

    An improved tomographic technique for determining the power distribution of an electron or ion beam using electron beam profile data acquired by an enhanced modified Faraday cup to create an image of the current density in high and low power ion or electron beams. A refractory metal disk with a number of radially extending slits, one slit being about twice the width of the other slits, is placed above a Faraday cup. The electron or ion beam is swept in a circular pattern so that its path crosses each slit in a perpendicular manner, thus acquiring all the data needed for a reconstruction in one circular sweep. The enlarged slit enables orientation of the beam profile with respect to the coordinates of the welding chamber. A second disk having slits therein is positioned below the first slit disk and inside of the Faraday cup and provides a shield to eliminate the majority of secondary electrons and ions from leaving the Faraday cup. Also, a ring is located below the second slit disk to help minimize the amount of secondary electrons and ions from being produced. In addition, a beam trap is located in the Faraday cup to provide even more containment of the electron or ion beam when full beam current is being examined through the center hole of the modified Faraday cup.

  12. Crosscheck of different techniques for two dimensional power spectral density measurements of x-ray optics

    SciTech Connect (OSTI)

    Yashchuk, Valeriy V.; Irick, Steve C.; Gullikson, Eric M.; Howells, Malcolm R.; MacDowell, Alastair A.; McKinney, Wayne R.; Salmassi, Farhad; Warwick, Tony

    2005-07-12T23:59:59.000Z

    The consistency of different instruments and methods for measuring two-dimensional (2D) power spectral density (PSD) distributions are investigated. The instruments are an interferometric microscope, an atomic force microscope (AFM) and the X-ray Reflectivity and Scattering experimental facility, all available at Lawrence Berkeley National Laboratory. The measurements were performed with a gold-coated mirror with a highly polished stainless steel substrate. It was shown that these three techniques provide essentially consistent results. For the stainless steel mirror, an envelope over all measured PSD distributions can be described with an inverse power-law PSD function. It is also shown that the measurements can be corrected for the specific spatial frequency dependent systematic errors of the instruments. The AFM and the X-ray scattering measurements were used to determine the modulation transfer function of the interferometric microscope. The corresponding correction procedure is discussed in detail. Lower frequency investigation of the 2D PSD distribution was also performed with a long trace profiler and a ZYGO GPI interferometer. These measurements are in some contradiction, suggesting that the reliability of the measurements has to be confirmed with additional investigation. Based on the crosscheck of the performance of all used methods, we discuss the ways for improving the 2D PSD characterization of X-ray optics.

  13. Composite Cathode for High-Power Density Solid Oxide Fuel Cells

    SciTech Connect (OSTI)

    Ilwon Kim; Scott Barnett; Yi Jiang; Manoj Pillai; Nikkia McDonald; Dan Gostovic; Zhongryang Zhan; Jiang Liu

    2004-01-31T23:59:59.000Z

    Reduction of solid oxide fuel cell (SOFC) operating temperature will play a key role in reducing the stack cost by allowing the use of low-cost metallic interconnects and new approaches to sealing, while making applications such as transportation more feasible. Reported results for anode-supported SOFCs show that cathode polarization resistance is the primary barrier to achieving high power densities at operating temperatures of 700 C and lower. This project aims to identify and develop composite cathodes that could reduce SOFC operating temperatures below 700 C. This effort focuses on study and use of (La,Sr)(Co,Fe)O{sub 3} (LSCF) based composite cathodes, which have arguably the best potential to substantially improve on the currently-used, (La,Sr)MnO{sub 3}-Yttria-stabilized Zirconia. During this Phase I, it was successfully demonstrated that high performances can be achieved with LSCF/Gadolinium-Doped Ceria composite cathodes on Ni-based anode supported cells operating at 700 C or lower. We studied electrochemical reactions at LSCF/Yttria-stabilized Zirconia (YSZ) interfaces, and observed chemical reactions between LSCF and YSZ. By using ceria electrolytes or YSZ electrolytes with ceria diffusion barrier layers, the chemical reactions between LSCF and electrolytes were prevented under cathode firing conditions necessary for the optimal adhesion of the cathodes. The protection provided by ceria layer is expected to be adequate for stable long-term cathode performances, but more testing is needed to verify this. Using ceria-based barrier layers, high performance Ni-YSZ anode supported cells have been demonstrated with maximum power densities of 0.8W/cm2 at 700 C and 1.6W/cm{sup 2} at 800 C. Ni-SDC anode supported cells with SDC electrolytes yielded >1W/cm{sup 2} at 600 C. We speculate that the power output of Ni-YSZ anode supported cell at 700 C and lower, was limited by the quality of the Ceria and Ceria YSZ interface. Improvements in the low-temperature performances are expected based on further development of barrier layer fabrication processes and optimization of cathode microstructure.

  14. Coexistence of the spini-density-wave and superconductivity in the Ba1-xKxFe2As2

    SciTech Connect (OSTI)

    Bao, Wei [Los Alamos National Laboratory; Chen, H [HEFEI NAT. LAB; Ren, Y [ANL; Qiu, Y [NIST CENTER FOR NEUTRON; Liu, R [HEFEI NAT. LAB.; Wu, G H [HEFEI NAT. LAB; Wu, T [HEFEI NAT. LAB.; Xie, Y L [HEFEI NAT. LAB; Wang, F [HEFEI NAT. LAB.; Huang, Q [NIST CENTER FOR NEUTRON; Chen, X H [HEFEI NAT. LAB

    2008-01-01T23:59:59.000Z

    The relation between the spin-density-wave (SDW) and superconducting order is a central topic in current research on the FeAs-based high T{sub c} superconductors. Conflicting results exist in the LaFeAs(O,F)-class of materials, for which whether the SDW and superconductivity are mutually exclusive or they can coexist has not been settled. Here we show that for the (Ba,K)Fe{sub 2}As{sub 2} system, the SDW and superconductivity can coexist in an extended range of compositions. The availability of single crystalline samples and high value of the energy gaps would make the materials a model system to investigate the high T{sub c} ferropnictide superconductivity.

  15. Effect of Chemical Pressure on the Charge Density Wave Transition in

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField Campaign:INEA :Work4/11ComputationalEdNERSC: DeliveringEdwinover

  16. Waves

    E-Print Network [OSTI]

    LaCure, Mari Mae

    2010-04-29T23:59:59.000Z

    Waves is the supporting document to the Master of Fine Arts thesis exhibition of the same title. Exhibited March 7-12 2010 in the Art and Design Gallery at the University of Kansas, Waves was comprised of a series of mixed media drawings...

  17. Journal of Power Sources 140 (2005) 331339 Numerical study of a flat-tube high power density solid oxide fuel cell

    E-Print Network [OSTI]

    2005-01-01T23:59:59.000Z

    ) solid oxide fuel cell (SOFC) is a new design developed by Siemens Westinghouse, based on their formerly.V. All rights reserved. Keywords: Flat-tube; High power density; Solid oxide fuel cell; Simulation; Heat oxide fuel cell Part I. Heat/mass transfer and fluid flow Yixin Lu1, Laura Schaefer, Peiwen Li2

  18. Observation and modeling of mixing-layer development in high-energy-density, blast-wave-driven shear flow

    SciTech Connect (OSTI)

    Di Stefano, C. A., E-mail: carlosds@umich.edu; Kuranz, C. C.; Klein, S. R.; Drake, R. P. [Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States)] [Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Malamud, G. [Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States) [Department of Atmospheric, Oceanic, and Space Sciences, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Physics, Nuclear Research Center-Negev, Beer-Sheva (Israel); Henry de Frahan, M. T.; Johnsen, E. [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States)] [Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan 48109 (United States); Shimony, A.; Shvarts, D. [Department of Physics, Nuclear Research Center-Negev, Beer-Sheva (Israel) [Department of Physics, Nuclear Research Center-Negev, Beer-Sheva (Israel); Department of Physics, Ben-Gurion University, Beer-Sheva (Israel); Smalyuk, V. A.; Martinez, D. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)] [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)

    2014-05-15T23:59:59.000Z

    In this work, we examine the hydrodynamics of high-energy-density (HED) shear flows. Experiments, consisting of two materials of differing density, use the OMEGA-60 laser to drive a blast wave at a pressure of ?50 Mbar into one of the media, creating a shear flow in the resulting shocked system. The interface between the two materials is Kelvin-Helmholtz unstable, and a mixing layer of growing width develops due to the shear. To theoretically analyze the instability's behavior, we rely on two sources of information. First, the interface spectrum is well-characterized, which allows us to identify how the shock front and the subsequent shear in the post-shock flow interact with the interface. These observations provide direct evidence that vortex merger dominates the evolution of the interface structure. Second, simulations calibrated to the experiment allow us to estimate the time-dependent evolution of the deposition of vorticity at the interface. The overall result is that we are able to choose a hydrodynamic model for the system, and consequently examine how well the flow in this HED system corresponds to a classical hydrodynamic description.

  19. Femtosecond x-rays link melting of charge density wave correlations and light-enhanced coherent transport in YBa?Cu?O?.?

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

    Forst, M. [Max-Planck Inst. for the Structure and Dynamics of Matter, Hamburg (Germany); Hill, J. P. [Brookhaven National Lab. (BNL), Upton, NY (United States); Frano, A. [Max-Planck Inst. for Solid State Research, Stuttgart (Germany); Helmholtz-Zentrum Berlin Fur Materialien und Energie, Berlin (Germany); Kaiser, S. [Max-Planck Inst. for the Structure and Dynamics of Matter, Hamburg (Germany); Mankowsky, R. [Max-Planck Inst. for the Structure and Dynamics of Matter, Hamburg (Germany); Hunt, C. R. [Max-Planck Inst. for the Structure and Dynamics of Matter, Hamburg (Germany); Univ. of Illinois at Urbana-Champaign, Urbana, IL (United States); Turner, J. J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Dakovski, G. L. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Minitti, M. P. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Robinson, J. [SLAC National Accelerator Lab., Menlo Park, CA (United States); Loew, T. [Max-Planck Inst. for Solid State Research, Stuttgart (Germany); Le Tacon, M. [Max-Planck Inst. for Solid State Research, Stuttgart (Germany); Keimer, B. [Max-Planck Inst. for Solid State Research, Stuttgart (Germany); Cavalleri, A. [Max-Planck Inst. for the Structure and Dynamics of Matter, Hamburg (Germany); Univ. of Oxford (United Kingdom); Dhesi, S. S. [Diamond Light Source, Chilton, Didcot (United Kingdom)

    2014-11-01T23:59:59.000Z

    We use femtosecond resonant soft x-ray diffraction to measure the optically stimulated ultrafast changes of charge density wave correlations in underdoped YBa?Cu?O?.?. We find that when coherent interlayer transport is enhanced by optical excitation of the apical oxygen distortions, at least 50% of the in-plane charge density wave order is melted. These results indicate that charge ordering and superconductivity may be competing up to the charge ordering transition temperature, with the latter becoming a hidden phase that is accessible only by nonlinear phonon excitation.

  20. The need for high density energy storage for wind turbine and solar power has proven to be a

    E-Print Network [OSTI]

    Botea, Adi

    1 The need for high density energy storage for wind turbine and solar power has proven applications where under-hood temperatures may exceed the 85 °C normal rating, where the Y5V and Y5R capacitors (currently ~0.22 F) is also considerable. The resultant devices are anticipated to be the new generation

  1. Ultralow-power local laser control of the dimer density in alkali-metal vapors through photodesorption

    E-Print Network [OSTI]

    Pankaj K. Jha; Konstantin E. Dorfman; Zhenhuan Yi; Luqi Yuan; Vladimir A. Sautenkov; Yuri V. Rostovtsev; George R. Welch; Aleksei M. Zheltikov; Marlan O. Scully

    2012-10-08T23:59:59.000Z

    Ultralow-power diode-laser radiation is employed to induce photodesorption of cesium from a partially transparent thin-film cesium adsorbate on a solid surface. Using resonant Raman spectroscopy, we demonstrate that this photodesorption process enables an accurate local optical control of the density of dimer molecules in alkali-metal vapors.

  2. Potential order-of-magnitude enhancement of wind farm power density via counter-rotating vertical-axis wind

    E-Print Network [OSTI]

    Dabiri, John O.

    Potential order-of-magnitude enhancement of wind farm power density via counter-rotating vertical an alternative approach to wind farming that has the potential to concurrently reduce the cost, size-axis wind turbine arrays John O. Dabiria) Graduate Aeronautical Laboratories and Bioengineering, California

  3. Active core profile and transport modification by application of Ion Bernstein Wave power in PBX-M

    SciTech Connect (OSTI)

    LeBlanc, B.; Bell, R. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Batha, S. [Fusion Physics and Technology, Torrance, CA (United States)] [and others

    1995-01-01T23:59:59.000Z

    Application of Ion Bernstein Wave Heating (IBWH) into the Princeton Beta Experiment-Modification (PBX-M) tokamak stabilizes sawtooth oscillations and generates peaked density profiles. A transport barrier, spatially correlated with the IBWH power deposition profile, is observed in the core of IBWH assisted neutral beam injection (NBI) discharges. A precursor to the fully developed barrier is seen in the soft x-ray data during edge localized mode (ELM) activity. Sustained IBWH operation is conducive to a regime where the barrier supports large {triangledown}n{sub e}, {triangledown}T{sub e}, {triangledown}v{sub phi}, and {triangledown}T{sub i}, delimiting the confinement zone. This regime is reminiscent of the H(high)-mode but with a confinement zone moved inwards. The core region has better than H-mode confinement while the peripheral region is L(low)-mode-like. The peaked profile enhanced NBI core deposition and increases nuclear reactivity. An increase in central T{sub i} results from {chi}{sub i} reduction (compared to H-mode) and better beam penetration. Bootstrap current fractions of up to 0.32--0.35 locally and 0.28 overall were obtained when an additional NBI burst is applied to this plasma.

  4. Fast-wave Power Flow Along SOL Field Lines In NSTX nd The Associated Power Deposition Profile Across The SOL In Front Of The Antenna

    SciTech Connect (OSTI)

    Perkins, Roy

    2013-06-21T23:59:59.000Z

    Fast-wave heating and current drive efficiencies can be reduced by a number of processes in the vicinity of the antenna and in the scrape off layer (SOL). On NSTX from around 25% to more than 60% of the high-harmonic fast-wave power can be lost to the SOL regions, and a large part of this lost power flows along SOL magnetic field lines and is deposited in bright spirals on the divertor floor and ceiling. We show that field-line mapping matches the location of heat deposition on the lower divertor, albeit with a portion of the heat outside of the predictions. The field-line mapping can then be used to partially reconstruct the profile of lost fast-wave power at the midplane in front of the antenna, and the losses peak close to the last closed flux surface (LCFS) as well as the antenna. This profile suggests a radial standing-wave pattern formed by fast-wave propagation in the SOL, and this hypothesis will be tested on NSTX-U. Advanced RF codes must reproduce these results so that such codes can be used to understand this edge loss and to minimize RF heat deposition and erosion in the divertor region on ITER.

  5. Proof of the the Riemann hypothesis from the strong density hypothesis via a power sum method

    E-Print Network [OSTI]

    Yuanyou Cheng; S. Albeverio

    2014-08-13T23:59:59.000Z

    The Riemann hypothesis is equivalent to the $\\varpi$-form of the prime number theorem as $\\varpi(x) =O(x\\sp{1/2} \\log\\sp{2} x)$, where $\\varpi(x) =\\sum\\sb{n\\le x}\\ \\bigl(\\Lambda(n) -1\\big)$ with the sum running through the set of all natural integers. Let ${\\mathsf Z}(s) = -\\tfrac{\\zeta\\sp{\\prime}(s)}{\\zeta(s)} -\\zeta(s)$. We use the classical integral formula for the Heaviside function in the form of ${\\mathsf H}(x) =\\int\\sb{m -i\\infty} \\sp{m +i\\infty} \\tfrac{x\\sp{s}}{s} \\dd s$ where $m >0$, and ${\\mathsf H}(x)$ is 0 when $\\tfrac{1}{2} 1$. However, we diverge from the literature by applying Cauchy's residue theorem to the function ${\\mathsf Z}(s) \\cdot \\tfrac{x\\sp{s}} {s}$, rather than $-\\tfrac{\\zeta\\sp{\\prime}(s)} {\\zeta(s)} \\cdot \\tfrac{x\\sp{s}}{s}$, so that we may utilize the formula for $\\tfrac{1}{2}1$ of ${\\mathsf Z}(s)$, we use induction to reduce the size of the exponent $\\theta$ in $\\varpi(x) =O(x\\sp{\\theta} \\log\\sp{2} x)$, while we also use induction on $x$ when $\\theta$ is fixed. We prove that the Riemann hypothesis is valid under the assumptions of the explicit strong density hypothesis and the Lindel\\"of hypothesis recently proven, via a result of the implication on the zero free regions from the remainder terms of the prime number theorem by the power sum method of Tur\\'an.

  6. LOW-TEMPERATURE, ANODE-SUPPORTED HIGH POWER DENSITY SOLID OXIDE FUEL CELLS WITH NANOSTRUCTURED ELECTRODES

    SciTech Connect (OSTI)

    Anil V. Virkar

    2002-03-26T23:59:59.000Z

    Anode-supported cells comprising Ni + yttria-stabilized zirconia (YSZ) anode, thin ({approx}10 {micro}m) YSZ electrolyte, and composite cathodes containing a mixture of La{sub 0.8}Sr{sub 0.2}MnO{sub (3-{delta})} (LSM) and La{sub 0.9}Sr{sub 0.1}Ga{sub 0.8}Mg{sub 0.2}O{sub (3-{lambda})} (LSGM) were fabricated. The relative proportions of LSGM and LSM were varied between 30 wt.% LSGM + 70 wt.% LSM and 70 wt.% LSGM + 30 wt.% LSM, while the firing temperature was varied between 1000 and 1200 C. The cathode interlayer composition had a profound effect on cathode performance at 800 C with overpotentials ranging between 60 and 425 mV at 1.0 A/cm{sup 2} and exhibiting a minimum for 50 wt.% LSGM + 50 wt.% LSM. The cathodic overpotential decreased with increasing firing temperature of the composite interlayer in the range 1000 {le} T {le} 1150 C, and then increased dramatically for the interlayer fired at 1200 C. The cell with the optimized cathode interlayer of 50 wt.% LSM + 50 wt.% LSGM fired at 1150 C exhibited an area specific cell resistance of 0.18 {Omega}cm{sup 2} and a maximum power density of 1.4 W/cm{sup 2} at 800 C. Chemical analysis revealed that LSGM reacts with YSZ above 1000 C to form the pyrochlore phase, La{sub 2}Zr{sub 2}O{sub 7}. The formation of the pyrochlore phase at the interface between the LSGM/LSM composite cathode and the YSZ electrolyte limits the firing time and temperature of the cathode interlayer.

  7. Power Maximization in Wave-Energy Converters Using Sampled -Data Extremum Seeking /

    E-Print Network [OSTI]

    Chen, Tianjia

    2013-01-01T23:59:59.000Z

    design optimization of wave energy converters con- sistingN. Sahinkaya. A review of wave energy converter technology.2009. [6] A.F.O. Falc˜ao. Wave energy utilization: A review

  8. Wind: wind power density maps at 50m above ground and 1km resolution...

    Open Energy Info (EERE)

    density for Ghana. (Purpose):HTMLREMOVEDHTMLREMOVEDTo provide information on the wind resource potential in Ghana. Data and Resources Download MapsZIP Download Maps More...

  9. Wind: wind power density GIS data at 50m above ground and 400m...

    Open Energy Info (EERE)

    density for Sri Lanka (Purpose):HTMLREMOVEDHTMLREMOVEDTo provide information on the wind resource potential within Sri Lanka and selected offshore areas (Supplemental...

  10. Wind: wind power density maps at 50 m above ground and 1km resolution...

    Open Energy Info (EERE)

    density for Cuba. (Purpose):HTMLREMOVEDHTMLREMOVEDTo provide information on the wind resource potential in Cuba. Data and Resources Download MapsZIP Download Maps More...

  11. The constraints on power spectrum of relic gravitational waves from current observations of large-scale structure of the Universe

    E-Print Network [OSTI]

    B. Novosyadlyj; S. Apunevych

    2004-12-02T23:59:59.000Z

    We carry out the determination of the amplitude of relic gravitational waves power spectrum. Indirect best-fit technique was applied to compare observational data and theory predictions. As observations we have used data on large-scale structure (LSS) of the Universe and anisotropy of cosmic microwave background (CMB) temperature. The conventional inflationary model with 11 parameters has been investigated, all of them evaluated jointly. This approach gave us a possibility to find parameters of power spectrum of gravitational waves along with statistical errors. The main result consists in following: WMAP data on power spectrum of CMB temperature fluctuations along with LSS data prefer model with small amplitude of tensor mode power spectrum, close to zero. The upper limit for its amplitude at quadupole harmonics T/S=0.6 at 95% C.L.

  12. Photoemission study of the electronic structure and charge density waves of Na2Ti2Sb2O

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

    Tan, S. Y.; Jiang, J.; Ye, Z. R.; Niu, X. H.; Song, Y.; Zhang, C. L.; Dai, P. C.; Xie, B. P.; Lai, X. C.; Feng, D. L.

    2015-04-30T23:59:59.000Z

    The electronic structure of Na2Ti2Sb2O single crystal is studied by photon energy and polarization dependent angle-resolved photoemission spectroscopy (ARPES). The obtained band structure and Fermi surface agree well with the band structure calculation of Na2Ti2Sb2O in the non-magnetic state, which indicates that there is no magnetic order in Na2Ti2Sb2O and the electronic correlation is weak. Polarization dependent ARPES results suggest the multi-band and multi-orbital nature of Na2Ti2Sb2O. Photon energy dependent ARPES results suggest that the electronic structure of Na2Ti2Sb2O is rather two-dimensional. Moreover, we find a density wave energy gap forms below the transition temperature and reaches 65 meV at 7 K, indicating that Na2Ti2Sb2O is likely a weakly correlated CDW material in the strong electron-phonon interaction regime. (author)

  13. High-resolution tangential absolute extreme ultraviolet arrays for radiated power density measurements on NSTX-U

    SciTech Connect (OSTI)

    Delgado-Aparicio, L.; Bell, R. E.; Diallo, A.; Gerhardt, S. P.; Kozub, T. A.; LeBlanc, B. P.; Stratton, B. C. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08540 (United States); Faust, I. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Tritz, K. [The Johns Hopkins University, Baltimore, Maryland 21209 (United States)

    2014-11-15T23:59:59.000Z

    The radiated-power-density diagnostic on the equatorial midplane for the NSTX-U tokamak will be upgraded to measure the radial structure of the photon emissivity profile with an improved radial resolution. This diagnostic will enhance the characterization and studies of power balance, impurity transport, and MHD. The layout and response expected of the new system is shown for different plasma conditions and impurity concentrations. The effect of toroidal rotation driving poloidal asymmetries in the core radiation from high-Z impurities is also addressed.

  14. Nano-structure multilayer technology fabrication of high energy density capacitors for the power electronic building book

    SciTech Connect (OSTI)

    Barbee, T.W.; Johnson, G.W.; Wagner, A.V.

    1997-10-21T23:59:59.000Z

    Commercially available capacitors do not meet the specifications of the Power Electronic Building Block (PEBB) concept. We have applied our propriety nanostructure multilayer materials technology to the fabrication of high density capacitors designed to remove this impediment to PEBB progress. Our nanostructure multilayer capacitors will also be enabling technology in many industrial and military applications. Examples include transient suppression (snubber capacitors), resonant circuits, and DC filtering in PEBB modules. Additionally, weapon applications require compact energy storage for detonators and pulsed-power systems. Commercial applications run the gamut from computers to lighting to communications. Steady progress over the last five years has brought us to the threshold of commercial manufacturability. We have demonstrated a working dielectric energy density of > 11 J/cm3 in 20 nF devices designed for 1 kV operation.

  15. Nuclear Instruments and Methods in Physics Research A 547 (2005) 663678 Determining axial fuel-rod power-density profiles from in-core

    E-Print Network [OSTI]

    Shultis, J. Kenneth

    is proposed for determining power-density profiles in nuclear reactor fuel rods from neutron flux measurementsNuclear Instruments and Methods in Physics Research A 547 (2005) 663­678 Determining axial fuel-rod power-density profiles from in-core neutron flux measurements J. Kenneth Shultis� Department

  16. Cooling Power Density of SiGe/Si Superlattice Micro Refrigerators Gehong Zeng, Xiaofeng Fan, Chris LaBounty, Edward Croke2

    E-Print Network [OSTI]

    Bowers, John

    Cooling Power Density of SiGe/Si Superlattice Micro Refrigerators Gehong Zeng, Xiaofeng Fan, Chris Experiments were carried out to determine the cooling power density of SiGe/Si superlattice microcoolers by integrating thin film metal resistor heaters on the cooling surface. By evaluating the maximum cooling

  17. The wind power probability density forecast problem can be formulated as: forecast the wind power pdf at time step t for each look-ahead time step t+k of a given time-horizon

    E-Print Network [OSTI]

    Kemner, Ken

    The wind power probability density forecast problem can be formulated as: forecast the wind power ahead) knowing a set of explanatory variables (e.g. numerical weather predictions (NWPs), wind power measured values). Translating this sentence to an equation, we have: where pt+k is the wind power

  18. Charge Density Wave Compounds

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office511041clothAdvanced Materials Advanced. C o w l i t z CPlasma of the Rotating Wall Machine by David

  19. The Density Perturbation Power Spectrum to Second-Order Corrections in the Slow-Roll Expansion

    E-Print Network [OSTI]

    Ewan D. Stewart; Jin-Ook Gong

    2001-02-17T23:59:59.000Z

    We set up a formalism that can be used to calculate the power spectrum of the curvature perturbations produced during inflation up to arbitrary order in the slow-roll expansion, and explicitly calculate the power spectrum and spectral index up to second-order corrections.

  20. LOW-TEMPERATURE, ANODE-SUPPORTED HIGH POWER DENSITY SOLID OXIDE FUEL CELLS WITH NANOSTRUCTURED ELECTRODES

    SciTech Connect (OSTI)

    Professor Anil V. Virkar

    2003-05-23T23:59:59.000Z

    This report summarizes the work done during the entire project period, between October 1, 1999 and March 31, 2003, which includes a six-month no-cost extension. During the project, eight research papers have, either been, published, accepted for publication, or submitted for publication. In addition, several presentations have been made in technical meetings and workshops. The project also has provided support for four graduate students working towards advanced degrees. The principal technical objective of the project was to analyze the role of electrode microstructure on solid oxide fuel cell performance. Prior theoretical work conducted in our laboratory demonstrated that the particle size of composite electrodes has a profound effect on cell performance; the finer the particle size, the lower the activation polarization, the better the performance. The composite cathodes examined consisted of electronically conducting perovskites such as Sr-doped LaMnO{sub 3} (LSM) or Sr-doped LaCoO{sub 3} (LSC), which is also a mixed conductor, as the electrocatalyst, and yttria-stabilized zirconia (YSZ) or rare earth oxide doped CeO{sub 2} as the ionic conductor. The composite anodes examined were mixtures of Ni and YSZ. A procedure was developed for the synthesis of nanosize YSZ by molecular decomposition, in which unwanted species were removed by leaching, leaving behind nanosize YSZ. Anode-supported cells were made using the as-synthesized powders, or using commercially acquired powders. The electrolyte was usually a thin ({approx}10 microns), dense layer of YSZ, supported on a thick ({approx}1 mm), porous Ni + YSZ anode. The cathode was a porous mixture of electrocatalyst and an ionic conductor. Most of the cell testing was done at 800 C with hydrogen as fuel and air as the oxidant. Maximum power densities as high as 1.8 W/cm{sup 2} were demonstrated. Polarization behavior of the cells was theoretically analyzed. A limited amount of cell testing was done using liquid hydrocarbon fuels where reforming was achieved internally. Significant polarization losses also occur at the anode, especially at high fuel utilizations. An analysis of polarization losses requires that various contributions are isolated, and their dependence on pertinent parameters is quantitatively described. An investigation of fuel composition on gas transport through porous anodes was investigated and the role of fuel diluents was explored. This work showed that the molecular weight of the diluent has a significant effect on anode concentration polarization. This further showed that the presence of some molecular hydrogen is necessary to minimize polarization losses. Theoretical analysis has shown that the electrode microstructure has a profound effect on cell performance. In a series of experiments, cathode microstructural parameters were varied, without altering other parameters. Cathode microstructural parameters, especially three phase boundary (TPB) length, were estimated using techniques in quantitative stereology. Cell performance was quantitatively correlated with the relevant microstructural parameters, and charge transfer resistivity was explicitly evaluated. This is the first time that a fundamental parameter, which governs the activation polarization, has been quantitatively determined. An important parameter, which governs the cathodic activation polarization, and thus cell performance, is the ionic conductivity of the composite cathode. The traditional composite cathode is a mixture of LSM and YSZ. It is well known that Sr and Mg-doped LaGaO{sub 3} (LSGM), exhibits higher oxygen ion conductivity compared to YSZ. Cells were fabricated with composite cathodes comprising a mixture of LSM and LSGM. Studies demonstrated that LSGM-based composite cathodes exhibit excellent behavior. Studies have shown that Ni + YSZ is an excellent anode. In fact, in most cells, the principal polarization losses, at least at low fuel utilizations, are associated with the cathode. Theoretical analysis conducted in our group has also shown that anode-supported cells exhibi

  1. Microwave power spectral density and its effects on exciting electrodeless high intensity discharge lamps

    SciTech Connect (OSTI)

    Butler, S.J.; Goss, H.H.; Lapatovich, W.P. [Osram Sylvania Inc., Salem, MA (United States)

    1995-12-31T23:59:59.000Z

    The effects of a microwave source generating a spectrally dense power spectrum on the operation of an electrodeless high intensity discharge lamp were measured. Spectrally pure sources operating within ISM bands at 915 MHz and 2.45 GHz produce stable capacitively coupled discharges useful for producing flicker-free light for numerous applications. The internal plasma temperature distribution and lamp geometry define acoustic resonance modes within the lamp which can be excited with power sidebands. The operation of lamps with commercially available power sources and custom built generators are discussed. Estimates of the spectral purity required for stable operation are provided.

  2. Density-potential pairs for spherical stellar systems with Sersic light-profiles and (optional) power-law cores

    E-Print Network [OSTI]

    Balsa Terzic; Alister W. Graham

    2005-06-10T23:59:59.000Z

    Popular models for describing the luminosity-density profiles of dynamically hot stellar systems (e.g., Jaffe, Hernquist, Dehnen) were constructed with the desire to match the deprojected form of an R^{1/4} light-profile. Real galaxies, however, are now known to have a range of different light-profile shapes that scale with mass. Consequently, although highly useful, the above models have implicit limitations, and this is illustrated here through their application to a number of real galaxy density profiles. On the other hand, the analytical density profile given by Prugniel & Simien (1997) closely matches the deprojected form of Sersic R^{1/n} light-profiles - including deprojected exponential light-profiles. It is thus applicable for describing bulges in spiral galaxies, dwarf elliptical galaxies, and both ordinary and giant elliptical galaxies. Here we provide simple equations, in terms of elementary and special functions, for the gravitational potential and force associated with this density profile. Furthermore, to match galaxies with partially depleted cores, and better explore the supermassive black hole / galaxy connection, we have added a power-law core to this density profile and derived similar expressions for the potential and force of this hybrid profile. Expressions for the mass and velocity dispersion, assuming isotropy, are also given. These models may also prove appropriate for describing the dark matter distribution in halos formed from LCDM cosmological simulations.

  3. Thermal Properties of Graphene and Applications for Thermal Management of High-Power Density Electronics

    E-Print Network [OSTI]

    Yan, Zhong

    2013-01-01T23:59:59.000Z

    Turin and A. A. Balandin, Electronics Letters 40, 81 (2004).REFERENCES G. E. Moore, Electronics 38 (1965). E. Pop, Nanofor High-power Electronics” PCSI-38:38th Conference on the

  4. Doped LiFePO? cathodes for high power density lithium ion batteries

    E-Print Network [OSTI]

    Bloking, Jason T. (Jason Thompson), 1979-

    2003-01-01T23:59:59.000Z

    Olivine LiFePO4 has received much attention recently as a promising storage compound for cathodes in lithium ion batteries. It has an energy density similar to that of LiCoO 2, the current industry standard for cathode ...

  5. Copper nanocrystal modified activated carbon for supercapacitors with enhanced volumetric energy and power density

    E-Print Network [OSTI]

    Cao, Guozhong

    capacitors (EDLCs) have evoked wide interest in recent years due to their ability to supply high power of EDLCs is based on the quick formation of a double layer of surface charges and counter materials for EDLCs should have large surface area to accumulate a large amount of charges, and a size

  6. Title: Crack Diagnostics via Fourier Transform: Real and Imaginary Components vs. Power Spectral Density

    E-Print Network [OSTI]

    Giurgiutiu, Victor

    Title: Crack Diagnostics via Fourier Transform: Real and Imaginary Components vs. Power Spectral simultaneously the real and imaginary components of the Fourier transforms as diagnostics features approach consists of using new features based on the real and imaginary parts of the Fourier transform

  7. Pulse-Density Modulation for RF Applications: The Radio-Frequency Power Amplifier (RF PA)

    E-Print Network [OSTI]

    Sanders, Seth

    . This enables complex digital processing and control of RF switching waveforms. Trends in processing speed demonstrates, techniques previously used for audio amplifiers, motor control, and power conversion may now generations of CMOS technology. We implement digital control of the carrier amplitude using pulse

  8. Development of floating-type system for uranium extraction from seawater using sea current and wave power

    SciTech Connect (OSTI)

    Nobukawa, Hisashi; Kitamura, Mitsuru [Hiroshima Univ., Higashi-Hiroshima (Japan); Swilem, S.A.M. [Univ. of Alexandria (Egypt); Ishibashi, Kozo [Marine Technology Inst. Co., Ltd., Imari (Japan)

    1994-12-31T23:59:59.000Z

    The concept of a system for extracting uranium from seawater utilizing sea current and wave power is presented in this paper. The uranium absorption tests using model bed units whose size is 1/4 of the real absorbent system were carried out based on the concept design of the system. The model units are towed in the seawater with the velocity of about 2 knots for 30 hours. After the towing, the units were moored for 36 days in Imari Bay. Another absorption test, hanging the model bed units from a mooring ship in an open sea, was performed for 40 hours for assessing the effect of wave power in the uranium absorption. Based on the data obtained from the above tests, the production cost of uranium extraction was also calculated. It becomes about 34,000 yen/kg-uranium for extraction period of 60 days.

  9. Topographic power spectral density study of the effect of surface treatment processes on niobium for superconducting radio frequency accelerator cavities

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

    Xu, Chen; Tian, Hui; Reece, Charles E.; Kelley, Michael J.

    2012-04-01T23:59:59.000Z

    Microroughness is viewed as a critical issue for attaining optimum performance of superconducting radio frequency accelerator cavities. The principal surface smoothing methods are buffered chemical polish (BCP) and electropolish (EP). The resulting topography is characterized by atomic force microscopy (AFM). The power spectral density (PSD) of AFM data provides a more thorough description of the topography than a single-value roughness measurement. In this work, one dimensional average PSD functions derived from topography of BCP and EP with different controlled starting conditions and durations have been fitted with a combination of power law, K correlation, and shifted Gaussian models to extract characteristic parameters at different spatial harmonic scales. While the simplest characterizations of these data are not new, the systematic tracking of scale-specific roughness as a function of processing is new and offers feedback for tighter process prescriptions more knowledgably targeted at beneficial niobium topography for superconducting radio frequency applications.

  10. Power Maximization in Wave-Energy Converters Using Sampled -Data Extremum Seeking /

    E-Print Network [OSTI]

    Chen, Tianjia

    2013-01-01T23:59:59.000Z

    irregular waves. Ocean engineering, 26(7):625–651, 1999. [Engineering University of California, San Diego, 2013 Professor Sonia Martinez, Chair Ocean

  11. Nonlinear effects resulting from the interaction of a large-scale Alfven wave with a density filament

    E-Print Network [OSTI]

    California at Los Angles, University of

    through the plasma-sheet boundary layer in the earth's magnetosphere at altitudes of 4­6 Earth radii-scale wave are large enough to produce oscillatory velocities comparable to the electron thermal velocity

  12. Power Maximization in Wave-Energy Converters Using Sampled -Data Extremum Seeking /

    E-Print Network [OSTI]

    Chen, Tianjia

    2013-01-01T23:59:59.000Z

    power maximization problem while ensuring the system stability.of power extraction and ensures the stability of the system.power maximization problem while ensuring the stability of the system.

  13. Durability of Low Pt Fuel Cells Operating at High Power Density |

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

    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 DataDepartment of Energy Your Density Isn't Your Destiny:Revised Finding of No53197E TDrew Bittner About Us DrewDualLight-Duty2

  14. Riding the Clean Energy Wave: New Projects Aim to Improve Water Power Devices

    Office of Energy Efficiency and Renewable Energy (EERE)

    The Energy Department announces two projects as part of a larger effort to deploy innovative technologies for clean, domestic power generation from water power resources.

  15. MEMS Fuel Cells--Low Temp--High Power Density - 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: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville PowerCherries 82981-1cnHigh SchoolIn12electron 9November 6, In this3,Office of Science

  16. Physical interpretation of fractional diffusion-wave equation via lossy media obeying frequency power law

    E-Print Network [OSTI]

    Physical interpretation of fractional diffusion-wave equation via lossy media obeying frequency not been clearly explained in this regard. Here the attempt is made to interpret the FDWE via a new time, for example, in medical ultrasonic and seismic wave propagations ( )z eEE - = 0 7-9 . Here E represents

  17. Early structure formation from primordial density fluctuations with a blue-tilted power spectrum

    E-Print Network [OSTI]

    Hirano, Shingo; Yoshida, Naoki; Spergel, David; Yorke, Harold W

    2015-01-01T23:59:59.000Z

    While observations of large-scale structure and the cosmic microwave background (CMB) provide strong constraints on the amplitude of the primordial power spectrum (PPS) on scales larger than 10 Mpc, the amplitude of the power spectrum on sub-galactic length scales is much more poorly constrained. We study early structure formation in a cosmological model with a blue-tilted PPS. We assume that the standard scale-invariant PPS is modified at small length scales as $P(k) \\sim k^{m_{\\rm s}}$ with $m_{\\rm s} > 1$. We run a series of cosmological hydrodynamic simulations to examine the dependence of the formation epoch and the characteristic mass of primordial stars on the tilt of the PPS. In models with $m_{\\rm s} > 1$, star-forming gas clouds are formed at $z > 100$, when formation of hydrogen molecules is inefficient because the intense CMB radiation destroys chemical intermediates. Without efficient coolant, the gas clouds gravitationally contract while keeping a high temperature. The protostars formed in such ...

  18. Improving the AGR Fuel Testing Power Density Profile Versus Irradiation-Time in the Advanced Test Reactor

    SciTech Connect (OSTI)

    Gray S. Chang; David A. Petti; John T. Maki; Misti A. Lillo

    2009-05-01T23:59:59.000Z

    The Very High Temperature gas-cooled Reactor (VHTR), which is currently being developed, achieves simplification of safety through reliance on ceramic-coated fuel particles. Each TRISO-coated fuel particle has its own containment which serves as the principal barrier against radionuclide release under normal operating and accident conditions. These fuel particles, in the form of graphite fuel compacts, are currently undergoing a series of irradiation tests in the Advanced Test Reactor (ATR) at the Idaho National Laboratory (INL) to support the Advanced Gas-Cooled Reactor (AGR) fuel qualification program. A representive coated fuel particle with an 235U enrichment of 19.8 wt% was used in this analysis. The fuel burnup analysis tool used to perform the neutronics study reported herein, couples the Monte Carlo transport code MCNP, with the radioactive decay and burnup code ORIGEN2. The fuel burnup methodology known as Monte-Carlo with ORIGEN2 (MCWO) was used to evaluate the AGR experiment assembly and demonstrate compliance with ATR safety requirements. For the AGR graphite fuel compacts, the MCWO-calculated fission power density (FPD) due to neutron fission in 235U is an important design parameter. One of the more important AGR fuel testing requirements is to maintain the peak fuel compact temperature close to 1250°C throughout the proposed irradiation campaign of 550 effective full power days (EFPDs). Based on the MCWO-calculated FPD, a fixed gas gap size was designed to allow regulation of the fuel compact temperatures throughout the entire fuel irradiation campaign by filling the gap with a mixture of helium and neon gases. The chosen fixed gas gap can only regulate the peak fuel compact temperature in the desired range during the irradiation test if the ratio of the peak power density to the time-dependent low power density (P/T) at 550 EFPDs is less than 2.5. However, given the near constant neutron flux within the ATR driver core and the depletion of 235U in the graphite fuel compacts versus EFPD, the P/T ratio was calculated to be 5.3, which is unacceptable given the fuel compact temperature control requirement. To flatten the FPD profile versus EFPDs, two proposed options are – (a) add fertile (232Th) particles to the fuel compact and (b) add burnable absorber (B4C) to the graphite holder. The effectiveness of these two proposed options to flatten the FPD profile versus EFPDs were investigated and the results are compared in this study.

  19. Generation of primordial cosmological density inhomogeneities with scale invariant power spectrum during the standard radiation dominated expansion of the universe

    E-Print Network [OSTI]

    Oaknin, David H

    2007-01-01T23:59:59.000Z

    The expansion/contraction of a bubble of gas of radius $R_0(t)$ immersed in an incompressible fluid that fills the infinite 3D space around it, $r \\ge R_0(t)$, generates a radial flow, ${\\vec v}(r,t) = \\frac{R^2_0(t)}{r^2}\\ \\dot{R}_0(t) {\\hat r}$, which is set by the velocity of the bubble surface, $\\dot{R}_0(t)$. The kinetic energy that the expanding/contracting bubble pumps, at the expense of its own internal energy, into each unit volume of the flowing incompressible fluid is ${\\it e}(r,t) = \\frac{\\rho_0}{2} |{\\vec v}(r,t)|^2 = \\frac{\\rho_0}{2} \\dot{R}^2_0(t) R^4_0(t) r^{-4}$, where $\\rho_0$ is the mass density of the fluid. This incompressible flow generates equal time energy density (anti)correlations over infinitely long distances. They are imposed by global conservation laws and, therefore, do not violate causality. We notice that energy density inhomogeneities that are (anti)correlated as $f(r) \\sim - r^{-4}$ as $r \\to \\infty$ have scale invariant power spectrum in the range of very small wavenumbers,...

  20. Plasma physics and related challenges of millimeter-wave-to-terahertz and high power microwave generationa...

    E-Print Network [OSTI]

    Smith, James E.

    confronting "classic" high power microwave HPM generators including long-life bright electron beam sources, high power mmw-to-THz sources are compared and contrasted to those of HPM generation, and future assume long pulse or average power, with exceptions be- tween 1 and 10 GHz for high power microwave HPM

  1. CONSTRAINTS ON THE HIGH-l POWER SPECTRUM OF MILLIMETER-WAVE ANISOTROPIES FROM APEX-SZ

    SciTech Connect (OSTI)

    Reichardt, C. L.; Zahn, O.; Ferrusca, D.; Holzapfel, W. L.; Johnson, B. R.; Lee, A. T.; Lueker, M. [Department of Physics, University of California, Berkeley, CA 94720 (United States); Ade, P. A. R.; Lanting, T. [School of Physics and Astronomy, Cardiff University, CF24 3YB (United Kingdom); Basu, K.; Chon, G.; Kneissl, R. [Max Planck Institute for Radioastronomy, 53121 Bonn (Germany); Bender, A. N.; Halverson, N. W. [Center for Astrophysics and Space Astronomy, Department of Astrophysical and Planetary Sciences, University of Colorado, Boulder, CO 80309 (United States); Bertoldi, F. [Argelander Institute for Astronomy, Bonn University, Bonn (Germany); Cho, H.-M. [National Institute of Standards and Technology, Boulder, CO 80305 (United States); Dobbs, M.; Kennedy, J. [Department of Physics, McGill University, Montreal, H3A 2T8 (Canada); Horellou, C.; Johansson, D. [Onsala Space Observatory, Chalmers University of Technology, SE-439 92 Onsala (Sweden)] (and others)

    2009-08-20T23:59:59.000Z

    We present measurements of the angular power spectrum of millimeter wave anisotropies with the APEX-SZ instrument. APEX-SZ has mapped 0.8 deg{sup 2} of sky at a frequency of 150 GHz with an angular resolution of 1'. These new measurements significantly improve the constraints on anisotropy power at 150 GHz over the range of angular multipoles 3000 < l < 10, 000, limiting the total astronomical signal in a flat band power to be less than 105 {mu}K{sup 2} at 95% CL. We expect both submillimeter-bright, dusty galaxies and to a lesser extent secondary cosmic microwave background anisotropies from the Sunyaev-Zel'dovich effect (SZE) to significantly contribute to the observed power. Subtracting the SZE power spectrum expected for {sigma}{sub 8} = 0.8 and masking bright sources, the best-fit value for the remaining power is C {sub l} = 1.1{sup +0.9} {sub -0.8} x 10{sup -5} {mu}K{sup 2} (1.7{sup +1.4} {sub -1.3} Jy{sup 2} sr{sup -1}). This agrees well with model predictions for power due to submillimeter-bright, dusty galaxies. Comparing this power to the power detected by BLAST at 600 GHz, we find the frequency dependence of the source fluxes to be S{sub {nu}}{proportional_to}{nu}{sup 2.6+0.4}{sub -0.2}} if both experiments measure the same population of sources. Simultaneously fitting for the amplitude of the SZE power spectrum and a Poisson-distributed point source population, we place an upper limit on the matter fluctuation amplitude of {sigma}{sub 8} < 1.18 at 95% confidence.

  2. Increasing the power density when using inert matrix fuels to reduce production of transuranics

    SciTech Connect (OSTI)

    Recktenwald, G.D.; Deinert, M.R. [University of Texas, 1 University Station C2200, Austin TX 78715-0162 (United States)

    2013-07-01T23:59:59.000Z

    Reducing the production of transuranics is a goal of most advanced nuclear fuel cycles. One way to do this is to recycle the transuranics into the same reactors that are currently producing them using an inert matrix fuel. In previous work we have modeled such a reactor where 72%, of the core is comprised of standard enriched uranium fuel pins, with the remaining 28% fuel made from Yttria stabilized zirconium, in which transuranics are loaded. A key feature of this core is that all of the transuranics produced by the uranium fuel assemblies are later burned in inert matrix fuel assemblies. It has been shown that this system can achieve reductions in transuranic waste of more than 86%. The disadvantage of such a system is that the core power rating must be significantly lower than a standard pressurized water reactor. One reason for the lower power is that high burnup of the uranium fuel precludes a critical level of reactivity at the end of the campaign. Increasing the uranium enrichment and changing the pin pitch are two ways to increase burnup while maintaining criticality. In this paper we use MCNPX and a linear reactivity model to quantify the effect of these two parameters on the end of campaign reactivity. Importantly, we show that in the region of our proposed reactor, enrichment increases core reactivity by 0.02 per percent uranium 235 and pin pitch increases reactivity by 0.02 per mm. Reactivity is lost at a rate of 0.005 per MWd/kgIHM uranium burnup. (authors)

  3. Order-of-magnitude enhancement of wind farm power density via counter-rotating vertical-axis wind turbine arrays

    E-Print Network [OSTI]

    Dabiri, John O

    2010-01-01T23:59:59.000Z

    Modern wind farms require significant land resources to separate each wind turbine from the adjacent turbine wakes. These aerodynamic constraints limit the amount of power that can be extracted from a given wind farm footprint. We conducted full-scale field tests of vertical-axis wind turbines in counter-rotating configurations under natural wind conditions. Whereas wind farms consisting of propeller-style turbines produce 2 to 3 watts of power per square meter of land area, these field tests indicate that power densities approaching 100 W m^-2 can be achieved by arranging vertical-axis wind turbines in layouts that enable them to extract energy from adjacent wakes. In addition, we calculated that the global wind resource available to 10-m tall turbines based on the present approach is approximately 225 trillion watts (TW), which significantly exceeds the global wind resource available to 80-m tall, propeller-style wind turbines, approximately 75 TW. This improvement is due to the closer spacing that can be a...

  4. High Current Density, Long Life Cathodes for High Power RF Sources

    SciTech Connect (OSTI)

    Ives, Robert Lawrence [Calabazas Creek Research,, Inc.; Collins, George [Calabazas Creek Research, Inc.; Falce, Lou [Consultant; Schwartzkopf, Steve [Ron Witherspoon, Inc.; Busbaher, Daniel [Semicon Associates

    2014-01-22T23:59:59.000Z

    This program was tasked with improving the quality and expanding applications for Controlled Porosity Reservoir (CPR) cathodes. Calabazas Creek Research, Inc. (CCR) initially developed CPR cathodes on a DOE-funded SBIR program to improve cathodes for magnetron injection guns. Subsequent funding was received from the Defense Advanced Research Projects Agency. The program developed design requirements for implementation of the technology into high current density cathodes for high frequency applications. During Phase I of this program, CCR was awarded the prestigious 2011 R&D100 award for this technology. Subsequently, the technology was presented at numerous technical conferences. A patent was issued for the technology in 2009. These cathodes are now marketed by Semicon Associates, Inc. in Lexington, KY. They are the world’s largest producer of cathodes for vacuum electron devices. During this program, CCR teamed with Semicon Associates, Inc. and Ron Witherspoon, Inc. to improve the fabrication processes and expand applications for the cathodes. Specific fabrications issues included the quality of the wire winding that provides the basic structure and the sintering to bond the wires into a robust, cohesive structure. The program also developed improved techniques for integrating the resulting material into cathodes for electron guns.

  5. MHK Projects/Wave Powered Pumping of Seawater for On Shore Use...

    Open Energy Info (EERE)

    s Cove Burin Peninsula, Newfoundland Project Country Canada Project Resource Click here Wave Coordinates 46.53, -55.4 Project Phase Phase 3 Project Details Although SARAHS Pump...

  6. Integration of Wave and Tidal Power into the Haida Gwaii Electrical Grid

    E-Print Network [OSTI]

    Victoria, University of

    , Canada that relies heavily on diesel fuel for energy generation. An investigation is done into the potential for electricity generation using both tidal stream and wave energy in Haida Gwaii. A mixed integer

  7. Electronic Instability in a Zero-Gap Semiconductor: The Charge-Density Wave in (TaSe4)2I

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

    Tournier-Colletta, C.; Moreschini, L.; Autès, G.; Moser, S.; Crepaldi, A.; Berger, H.; Walter, A. L.; Kim, K. S.; Bostwick, A.; Monceau, P.; Rotenberg, E.; Yazyev, O. V.; Grioni, M.

    2013-06-01T23:59:59.000Z

    We report a comprehensive study of the paradigmatic quasi-1D compound (TaSe4)2I performed by means of angle-resolved photoemission spectroscopy (ARPES) and first-principles electronic structure calculations. We find it to be a zero-gap semiconductor in the nondistorted structure, with non-negligible interchain coupling. Theory and experiment support a Peierls-like scenario for the charge-density wave formation below TCDW=263??K, where the incommensurability is a direct consequence of the finite interchain coupling. The formation of small polarons, strongly suggested by the ARPES data, explains the puzzling semiconductor-to-semiconductor transition observed in transport at TCDW.

  8. CONTROL OF POPULATION DENSITIES SURROUNDING NUCLEAR POWER PLANTS. VOLUME 5 OF THE FINAL REPORT ON HEALTH AND SAFETY IMPACTS OF NUCLEAR, GEOTHERMAL, AND FOSSIL-FUEL ELECTRIC GENERATION IN CALIFORNIA

    E-Print Network [OSTI]

    Nero, jA.V.

    2010-01-01T23:59:59.000Z

    Related Standards for Nuclear Power Plants," by A.V. NeroResponse Planning for Nuclear Power Plants in California,"Densities Surrounding Nuclear Power Plants," by A.V. Nero,

  9. 1204 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 34, NO. 9, SEPTEMBER 1999 Breakdown in Millimeter-Wave Power InP

    E-Print Network [OSTI]

    del Alamo, Jesús A.

    1204 IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 34, NO. 9, SEPTEMBER 1999 Breakdown in Millimeter-Wave Power InP HEMT's: A Comparison with GaAs PHEMT's J. A. del Alamo and M. H. Somerville Abstract's) deliver lower output power than GaAs pseudomorphic HEMT's (PHEMT's) throughout most of the millimeter

  10. Generation of Alfven waves by high power pulse at the electron plasma frequency

    E-Print Network [OSTI]

    California at Los Angles, University of

    to a pulse of field aligned superthermal electrons. This electron current pulse then launches an Alfve´n wave with w wci. In space plasmas, there are many instances where pulses of field aligned superthermal-plasma interaction is the means of generating the electron pulse. Superthermal electron pulses, with duration

  11. IEEE MICROWAVE AND GUIDED WAVE LETTERS, VOL. 9, NO. 7, JULY 1999 277 18-GHz GaN-Based Power Amplifier

    E-Print Network [OSTI]

    York, Robert A.

    IEEE MICROWAVE AND GUIDED WAVE LETTERS, VOL. 9, NO. 7, JULY 1999 277 1­8-GHz GaN-Based Power, Senior Member, IEEE Abstract-- We report the first gallium nitride (GaN)-based broad-band power amplifier. The circuit was fabricated on an AlN substrate using AlGaN/GaN power high-electron mobil- ity transistors

  12. Near-Millimeter Wave Issues for a Space Power Grid Narayanan Komerath, Vigneshwar Venkat, Jason Fernandez

    E-Print Network [OSTI]

    to the commissioning of renewable power plants, thus reducing lag between investment and revenue generation. 4@gatech.edu Abstract This paper reports continuing work on an evolutionary revenue-generating approach to Space Solar reports continuing work on an evolutionary revenue-generating approach to Space Solar Power. The concept

  13. Experimental determination of radiated internal wave power without pressure field Frank M. Lee,1

    E-Print Network [OSTI]

    Morrison, Philip J.,

    = S d2 x pv · ^n , (1) where J = pv is the baroclinic energy flux, p is the perturbed pressure field, v to determine, using only velocity field data, the time-averaged energy flux J and total radiated power P) that can be used to compute the energy flux and power from any two-dimensional velocity field data. PACS

  14. Gravitational waves from a curvaton model with blue spectrum

    SciTech Connect (OSTI)

    Kawasaki, Masahiro; Kitajima, Naoya; Yokoyama, Shuichiro, E-mail: kawasaki@icrr.u-tokyo.ac.jp, E-mail: nk610@icrr.u-tokyo.ac.jp, E-mail: shu@icrr.u-tokyo.ac.jp [Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba 277-8582 (Japan)

    2013-08-01T23:59:59.000Z

    We investigate the gravitational wave background induced by the first order scalar perturbations in the curvaton models. We consider the quadratic and axion-like curvaton potential which can generate the blue-tilted power spectrum of curvature perturbations on small scales and derive the maximal amount of gravitational wave background today. We find the power spectrum of the induced gravitational wave background has a characteristic peak at the frequency corresponding to the scale reentering the horizon at the curvaton decay, in the case where the curvaton does not dominate the energy density of the Universe. We also find the enhancement of the amount of the gravitational waves in the case where the curvaton dominates the energy density of the Universe. Such induced gravitational waves would be detectable by the future space-based gravitational wave detectors or pulsar timing observations.

  15. High-power and wavelength-tunable traveling-wave semiconductor ring laser

    E-Print Network [OSTI]

    Peng, En Titus

    1991-01-01T23:59:59.000Z

    purely electromagnetic effect, in contrast to traditional mechanically based instruments typified by the spinning-wheel gyroscope. Recent work on semiconductor ring lasers and erbium fiber ring lasers are largely directed towards achieving narrow..., "Narrow spectral linewidth semiconductor optical-fiber ring laser, " Appl. Phys. Lett?voL 49, pp. 1328-1330, 1986. [4] P, R, Morkel, G. J. Cowle, and D. N. Payne, "Travelling-wave erbium fibre ring laser with 60 kHz linewidth, " Electron. Lett. , vol...

  16. AIP/123-QED Experimental determination of radiated internal wave power without pressure field

    E-Print Network [OSTI]

    Texas at Austin. University of

    S is given by, P = S d2 x J · ^n = S d2 x pv · ^n , (1) where J = pv is the baroclinic energy flux, p, using only velocity field data, the time-averaged energy flux J and total radiated power P for two the energy flux and power from any two-dimensional velocity field data. PACS numbers: Valid PACS appear here

  17. Ion beam driven ion-acoustic waves in a plasma cylinder with negatively charged dust grains

    SciTech Connect (OSTI)

    Sharma, Suresh C.; Walia, Ritu [Department of Physics, Maharaja Agrasen Institute of Technology, PSP Area Plot No.-1, Sector-22, Rohini, Delhi 110 086 (India); Sharma, Kavita [Department of Physics, Bhagwan Parshuram Institute of Technology, Sector-17, Rohini, New Delhi 110 089 (India)

    2012-07-15T23:59:59.000Z

    An ion beam propagating through a magnetized potassium plasma cylinder having negatively charged dust grains drives electrostatic ion-acoustic waves to instability via Cerenkov interaction. The phase velocity of sound wave increases with the relative density of negatively charged dust grains. The unstable wave frequencies and the growth rate increase, with the relative density of negatively charged dust grains. The growth rate of the unstable mode scales as one-third power of the beam density. The real part of frequency of the unstable mode increases with the beam energy and scales as almost the one-half power of the beam energy.

  18. High Cooling Power Density of SiGe/Si Superlattice Microcoolers Gehong Zeng, Xiaofeng Fan, Chris LaBounty, John E. Bowers, Edward Croke1

    E-Print Network [OSTI]

    High Cooling Power Density of SiGe/Si Superlattice Microcoolers Gehong Zeng, Xiaofeng Fan, Chris La, University of California, Santa Cruz, CA 95064 ABSTRACT Fabrication and characterization of SiGe for their potential monolithic integration with Si microelectronics. SiGe is a good thermoelectric material especially

  19. Power combiner

    DOE Patents [OSTI]

    Arnold, Mobius; Ives, Robert Lawrence

    2006-09-05T23:59:59.000Z

    A power combiner for the combining of symmetric and asymmetric traveling wave energy comprises a feed waveguide having an input port and a launching port, a reflector for reflecting launched wave energy, and a final waveguide for the collection and transport of launched wave energy. The power combiner has a launching port for symmetrical waves which comprises a cylindrical section coaxial to the feed waveguide, and a launching port for asymmetric waves which comprises a sawtooth rotated about a central axis.

  20. Probing the plasma near high power wave launchers in fusion devices for static and dynamic electric fields (invited)

    SciTech Connect (OSTI)

    Klepper, C. C., E-mail: kleppercc@ornl.gov; Isler, R. C.; Biewer, T. M.; Caughman, J. B.; Green, D. L.; Harris, J. H.; Hillis, D. L. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6169 (United States); Martin, E. H. [Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831-6169 (United States); North Carolina State University, Raleigh, North Carolina 27607 (United States); Colas, L.; Goniche, M.; Hillairet, J.; Panayotis, S.; Pegourié, B.; Jacquot, J.; Lotte, Ph.; Colledani, G.; Ekedahl, A.; Litaudon, X. [CEA, IRFM, F-13108 Saint Paul-lez-Durance (France); Shannon, S. C. [North Carolina State University, Raleigh, North Carolina 27607 (United States)

    2014-11-15T23:59:59.000Z

    An exploratory study was carried out in the long-pulse tokamak Tore Supra, to determine if electric fields in the plasma around high-power, RF wave launchers could be measured with non-intrusive, passive, optical emission spectroscopy. The focus was in particular on the use of the external electric field Stark effect. The feasibility was found to be strongly dependent on the spatial extent of the electric fields and overlap between regions of strong (>?1 kV/cm) electric fields and regions of plasma particle recycling and plasma-induced, spectral line emission. Most amenable to the measurement was the RF electric field in edge plasma, in front of a lower hybrid heating and current drive launcher. Electric field strengths and direction, derived from fitting the acquired spectra to a model including time-dependent Stark effect and the tokamak-range magnetic field Zeeman-effect, were found to be in good agreement with full-wave modeling of the observed launcher.

  1. Probing the plasma near high power wave launchers in fusion devices for static and dynamic electric fields

    SciTech Connect (OSTI)

    Klepper, C Christopher [ORNL; Martin, Elijah H [ORNL; Isler, Ralph C [ORNL; Colas, L. [French Atomic Energy Commission (CEA), Cadarache, St. Paul lez Durance; Goniche, M. [French Atomic Energy Commission (CEA), Cadarache, St. Paul lez Durance; Hillairet, J. [French Atomic Energy Commission (CEA), Institute for Magnetic Fusion Research (IRFM); Panayotis, Stephanie [French Atomic Energy Commission (CEA), Institute for Magnetic Fusion Research (IRFM); Jacquot, Jonathan [French Atomic Energy Commission (CEA), Institute for Magnetic Fusion Research (IRFM); Lotte, Ph. [French Atomic Energy Commission (CEA), Cadarache, St. Paul lez Durance; Colledani, G. [French Atomic Energy Commission (CEA), Institute for Magnetic Fusion Research (IRFM); Biewer, Theodore M [ORNL; Caughman, J. B. O. [Oak Ridge National Laboratory (ORNL); Ekedahl, A. [French Atomic Energy Commission (CEA), Institute for Magnetic Fusion Research (IRFM); Green, David L [ORNL; Harris, Jeffrey H [ORNL; Hillis, Donald Lee [ORNL; Shannon, Prof. Steven [North Carolina State University; Litaudon, X [French Atomic Energy Commission (CEA)

    2014-01-01T23:59:59.000Z

    An exploratory study was carried out in the long-pulse tokamak Tore Supra, to determine if electric fields in the plasma around high-power, RF wave launchers could be measured with non-intrusive, passive, optical emission spectroscopy. The focus was in particular on the use of the external electric field Stark effect. The feasibility was found to be strongly dependent on the spatial extent of the electric fields and overlap between regions of strong (> 1 kV/cm) electric fields and regions of plasma particle recycling and plasma-induced, spectral line emission. Most amenable to the measurement was the RF electric field in edge plasma, in front of a lower hybrid heating and current drive launcher. Electric field strengths and direction, derived from fitting the acquired spectra to a model including time-dependent Stark effect and the tokamak-range magnetic field Zeeman-effect, were found to be in good agreement with full-wave modeling of the observed launcher.

  2. Observation of low magnetic field density peaks in helicon plasma

    SciTech Connect (OSTI)

    Barada, Kshitish K.; Chattopadhyay, P. K.; Ghosh, J.; Kumar, Sunil; Saxena, Y. C. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)

    2013-04-15T23:59:59.000Z

    Single density peak has been commonly observed in low magnetic field (<100 G) helicon discharges. In this paper, we report the observations of multiple density peaks in low magnetic field (<100 G) helicon discharges produced in the linear helicon plasma device [Barada et al., Rev. Sci. Instrum. 83, 063501 (2012)]. Experiments are carried out using argon gas with m = +1 right helical antenna operating at 13.56 MHz by varying the magnetic field from 0 G to 100 G. The plasma density varies with varying the magnetic field at constant input power and gas pressure and reaches to its peak value at a magnetic field value of {approx}25 G. Another peak of smaller magnitude in density has been observed near 50 G. Measurement of amplitude and phase of the axial component of the wave using magnetic probes for two magnetic field values corresponding to the observed density peaks indicated the existence of radial modes. Measured parallel wave number together with the estimated perpendicular wave number suggests oblique mode propagation of helicon waves along the resonance cone boundary for these magnetic field values. Further, the observations of larger floating potential fluctuations measured with Langmuir probes at those magnetic field values indicate that near resonance cone boundary; these electrostatic fluctuations take energy from helicon wave and dump power to the plasma causing density peaks.

  3. Experimental observation of standing wave effect in low-pressure very-high-frequency capacitive discharges

    SciTech Connect (OSTI)

    Liu, Yong-Xin; Gao, Fei; Liu, Jia; Wang, You-Nian, E-mail: ynwang@dlut.edu.cn [Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Physics and Optoelectronic Technology, Dalian University of Technology, Dalian 116024 (China)

    2014-07-28T23:59:59.000Z

    Radial uniformity measurements of plasma density were carried out by using a floating double probe in a cylindrical (21?cm in electrode diameter) capacitive discharge reactor driven over a wide range of frequencies (27–220 MHz). At low rf power, a multiple-node structure of standing wave effect was observed at 130?MHz. The secondary density peak caused by the standing wave effect became pronounced and shifts toward the axis as the driving frequency further to increase, indicative of a much more shortened standing-wave wavelength. With increasing rf power, the secondary density peak shift toward the radial edge, namely, the standing-wave wavelength was increased, in good qualitative agreement with the previous theory and simulation results. At higher pressures and high frequencies, the rf power was primarily deposited at the periphery of the electrode, due to the fact that the waves were strongly damped as they propagated from the discharge edge into the center.

  4. Innovative Deepwater Platform Aims to Harness Offshore Wind and Wave Power

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

    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 DataDepartment of Energy Your Density Isn't YourTransport(Fact Sheet),EnergyImprovementINDIANManagement1, 2010|InnovativeEnergyin|

  5. Compact, Low-Profile Power Converters: Highly-Laminated, High-Saturation-Flux-Density, Magnetic Cores for On-Chip Inductors in Power Converter Applications

    SciTech Connect (OSTI)

    None

    2010-09-01T23:59:59.000Z

    ADEPT Project: Georgia Tech is creating compact, low-profile power adapters and power bricks using materials and tools adapted from other industries and from grid-scale power applications. Adapters and bricks convert electrical energy into useable power for many types of electronic devices, including laptop computers and mobile phones. These converters are often called wall warts because they are big, bulky, and sometimes cover up an adjacent wall socket that could be used to power another electronic device. The magnetic components traditionally used to make adapters and bricks have reached their limits; they can't be made any smaller without sacrificing performance. Georgia Tech is taking a cue from grid-scale power converters that use iron alloys as magnetic cores. These low-cost alloys can handle more power than other materials, but the iron must be stacked in insulated plates to maximize energy efficiency. In order to create compact, low-profile power adapters and bricks, these stacked iron plates must be extremely thin-only hundreds of nanometers in thickness, in fact. To make plates this thin, Georgia Tech is using manufacturing tools used in microelectromechanics and other small-scale industries.

  6. In Situ Evaluation of Density, Viscosity and Thickness of Adsorbed Soft Layers by Combined Surface Acoustic Wave and Surface Plasmon Resonance

    E-Print Network [OSTI]

    L. Francis; J. -M. Friedt; C. Zhou; P. Bertrand

    2006-04-28T23:59:59.000Z

    We show the theoretical and experimental combination of acoustic and optical methods for the in situ quantitative evaluation of the density, the viscosity and the thickness of soft layers adsorbed on chemically tailored metal surfaces. For the highest sensitivity and an operation in liquids, a Love mode surface acoustic wave (SAW) sensor with a hydrophobized gold coated sensing area is the acoustic method, while surface plasmon resonance (SPR) on the same gold surface as the optical method is monitored simultaneously in a single set-up for the real-time and label-free measurement of the parameters of adsorbed soft layers, which means for layers with a predominant viscous behavior. A general mathematical modeling in equivalent viscoelastic transmission lines is presented to determine the correlation between experimental SAW signal shifts and the waveguide structure including the presence of the adsorbed layer and the supporting liquid from which it segregates. A methodology is presented to identify from SAW and SPR simulations the parameters representatives of the soft layer. During the absorption of a soft layer, thickness or viscosity changes are observed in the experimental ratio of the SAW signal attenuation to the SAW signal phase and are correlated with the theoretical model. As application example, the simulation method is applied to study the thermal behavior of physisorbed PNIPAAm, a polymer whose conformation is sensitive to temperature, under a cycling variation of temperature between 20 and 40 oC. Under the assumption of the bulk density and the bulk refractive index of PNIPAAm, thickness and viscosity of the film are obtained from simulations; the viscosity is correlated to the solvent content of the physisorbed layer.

  7. Status of High Power Tests of Normal Conducting Single-Cell Standing Wave Structures

    SciTech Connect (OSTI)

    Dolgashev, Valery; /SLAC; Tantawi, Sami; /SLAC; Yeremian, Anahid; /SLAC; Higashi, Yasuo; /KEK, Tsukuba; Spataro, Bruno; /INFN, Rome

    2012-06-25T23:59:59.000Z

    Our experiments are directed toward the understanding of the physics of rf breakdown in systems that can be used to accelerate electron beams at {approx}11.4 GHz. The structure geometries have apertures, stored energy per cell, and rf pulse duration close to that of the NLC or CLIC. The breakdown rate is the main parameter that we use to compare rf breakdown behavior for different structures at a given set of rf pulse parameters (pulse shape and peak power) at 60 Hz repetition rate. In our experiments, the typical range of the breakdown rate is from one per few hours to {approx}100 per hour. To date we have tested 29 structures. We consistently found that after the initial conditioning, the behavior of the breakdown rate is reproducible for structures of the same geometry and material, and the breakdown rate dependence on peak magnetic fields is stronger than on peak surface electric fields for structures of different geometries. Below we report the main results from tests of seven structures made from hard copper, soft copper alloys and hard-copper alloys. Additional details on these and other structures will be discussed in future publications.

  8. Low power low-density parity-checking (ldpc) codes decoder design using dynamic voltage and frequency scaling

    E-Print Network [OSTI]

    Wang, Weihuang

    2009-05-15T23:59:59.000Z

    This thesis presents a low-power LDPC decoder design based on speculative scheduling of energy necessary to decode dynamically varying data frame in both block-fading channels and general AWGN channels. A model of a memory-efficient low-power high...

  9. Performance Assessment of the Wave Dragon Wave Energy Converter

    E-Print Network [OSTI]

    Hansen, René Rydhof

    Performance Assessment of the Wave Dragon Wave Energy Converter Based on the EquiMar Methodology S of the wave energy sector, device developers are called to provide reliable estimates on power performanceMar, Nissum Bredning, Hanstholm, North Sea, Ekofisk, Wave-to-wire, Wave energy. I. INTRODUCTION The wave

  10. Kinetic Alfvén wave turbulence and formation of localized structures

    SciTech Connect (OSTI)

    Sharma, R. P. [Centre for Energy Studies, Indian Institute of Technology Delhi, Delhi 110016 (India)] [Centre for Energy Studies, Indian Institute of Technology Delhi, Delhi 110016 (India); Modi, K. V. [Centre for Energy Studies, Indian Institute of Technology Delhi, Delhi 110016 (India) [Centre for Energy Studies, Indian Institute of Technology Delhi, Delhi 110016 (India); Mechanical Engineering Department, Government Engineering College Valsad, Gujarat 396001 (India)

    2013-08-15T23:59:59.000Z

    This work presents non-linear interaction of magnetosonic wave with kinetic Alfvén wave for intermediate ?-plasma (m{sub e}/m{sub i}???1). A set of dimensionless equations have been developed for analysis by considering ponderomotive force due to pump kinetic Alfvén wave in the dynamics of magnetosonic wave. Stability analysis has been done to study modulational instability or linear growth rate. Further, numerical simulation has been carried out to study the nonlinear stage of instability and resulting power spectrum applicable to solar wind around 1 AU. Due to the nonlinearity, background density of magnetosonic wave gets modified which results in localization of kinetic Alfvén wave. From the obtained results, we observed that spectral index follows k{sup ?3.0}, consistent with observation received by Cluster spacecraft for the solar wind around 1 AU. The result shows the steepening of power spectrum which may be responsible for heating and acceleration of plasma particles in solar wind.

  11. Laboratory experiments on Alfven waves caused by rapidly expanding plasmas and their relationship to space phenomena

    E-Print Network [OSTI]

    California at Los Angles, University of

    arrive at the Earth they can induce currents in power lines and transformers, which, in turn, can disrupt. The Large Plasma Device (LAPD) at UCLA is a machine in which Alfve´n wave propagation in homogeneous in the production of intense shear and compressional Alfve´n waves, as well as large density perturbations

  12. Wind Wave Float

    Broader source: Energy.gov (indexed) [DOE]

    Water Power Peer Review WindWaveFloat Alla Weinstein Principle Power, Inc. aweinstein@principlepowerinc.com November 1, 2011 2 | Wind and Water Power Program eere.energy.gov...

  13. Internal Wave Interferometry

    E-Print Network [OSTI]

    Mathur, Manikandan S.

    Internal waves are a ubiquitous and significant means of momentum and energy transport in the oceans, atmosphere, and astrophysical bodies. Here, we show that internal wave propagation in nonuniform density stratifications, ...

  14. Designing materials for energy storage with high power and energy density : LiFePO? cathode material

    E-Print Network [OSTI]

    Kang, Byoungwoo

    2010-01-01T23:59:59.000Z

    LiFePO? has drawn a lot of attention as a cathode material in lithium rechargeable batteries because its structural and thermal stability, its inexpensive cost, and environmental friendliness meet the requirements of power ...

  15. THE 1998 NOVEMBER 14 OCCULTATION OF GSC 0622-00345 BY SATURN. II. STRATOSPHERIC THERMAL PROFILE, POWER SPECTRUM, AND GRAVITY WAVES

    SciTech Connect (OSTI)

    Harrington, Joseph [Planetary Sciences Group, Department of Physics, University of Central Florida, Orlando, FL 32816-2385 (United States); French, Richard G. [Astronomy Department, Wellesley College, Wellesley, MA 02481 (United States); Matcheva, Katia, E-mail: jh@physics.ucf.ed, E-mail: rfrench@wellesley.ed, E-mail: katia@phys.ufl.ed [Department of Physics, University of Florida, P.O. Box 118440, Gainesville, FL 32611 (United States)

    2010-06-10T23:59:59.000Z

    On 1998 November 14, Saturn and its rings occulted the star GSC 0622-00345. The occultation latitude was 55.{sup 0}5 S. This paper analyzes the 2.3 {mu}m light curve derived by Harrington and French. A fixed-baseline isothermal fit to the light curve has a temperature of 140 {+-} 3 K, assuming a mean molecular mass of 2.35 AMU. The thermal profile obtained by numerical inversion is valid between 1 and 60 {mu}bar. The vertical temperature gradient is > 0.2 K km{sup -1} more stable than the adiabatic lapse rate, but it still shows the alternating-rounded-spiked features seen in many temperature gradient profiles from other atmospheric occultations and usually attributed to breaking gravity (buoyancy) waves. We conduct a wavelet analysis of the thermal profile, and show that, even with our low level of noise, scintillation due to turbulence in Earth's atmosphere can produce large temperature swings in light-curve inversions. Spurious periodic features in the 'reliable' region of a wavelet amplitude spectrum can exceed 0.3 K in our data. We also show that gravity-wave model fits to noisy isothermal light curves can lead to convincing wave 'detections'. We provide new significance tests for localized wavelet amplitudes, wave model fits, and global power spectra of inverted occultation light curves by assessing the effects of pre- and post-occultation noise on these parameters. Based on these tests, we detect several significant ridges and isolated peaks in wavelet amplitude, to which we fit a gravity wave model. We also strongly detect the global power spectrum of thermal fluctuations in Saturn's atmosphere, which resembles the 'universal' (modified Desaubies) curve associated with saturated spectra of propagating gravity waves on Earth and Jupiter.

  16. System using a megawatt class millimeter wave source and a high-power rectenna to beam power to a suspended platform

    DOE Patents [OSTI]

    Caplan, Malcolm; Friedman, Herbert W.

    2005-07-19T23:59:59.000Z

    A system for beaming power to a high altitude platform is based upon a high power millimeter gyrotron source, optical transmission components, and a high-power receiving antenna (i.e., a rectenna) capable of rectifying received millimeter energy and converting such energy into useable electrical power.

  17. Poster presented at the OCEANS'11 Conference, September, 2011 Seeking Optimal Geometry of a Heaving Body for Improved Wave Power

    E-Print Network [OSTI]

    , standard of living, and dependency on technology indicate a future increase in energy demand (Fujita, 2002). This increase in energy demand coupled with recent concern for climate change and rising oil prices has the radiated wave amplitude at negative infinity (-) The plastic floater models have the same width as the wave

  18. Critical Parameters for Turbulent Transport in the SOL: Mechanism for the L-H Transition and its impact on the H-mode Power Threshold and Density Limit in ITER

    E-Print Network [OSTI]

    Critical Parameters for Turbulent Transport in the SOL: Mechanism for the L-H Transition and its impact on the H-mode Power Threshold and Density Limit in ITER

  19. EARLY AFTERGLOWS OF GAMMA-RAY BURSTS IN A STRATIFIED MEDIUM WITH A POWER-LAW DENSITY DISTRIBUTION

    SciTech Connect (OSTI)

    Yi, Shuang-Xi; Dai, Zi-Gao [School of Astronomy and Space Science, Nanjing University, Nanjing 210093 (China); Wu, Xue-Feng, E-mail: dzg@nju.edu.cn [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2013-10-20T23:59:59.000Z

    A long-duration gamma-ray burst (GRB) has been widely thought to arise from the collapse of a massive star, and it has been suggested that its ambient medium is a homogenous interstellar medium (ISM) or a stellar wind. There are two shocks when an ultra-relativistic fireball that has been ejected during the prompt gamma-ray emission phase sweeps up the circumburst medium: a reverse shock that propagates into the fireball, and a forward shock that propagates into the ambient medium. In this paper, we investigate the temporal evolution of the dynamics and emission of these two shocks in an environment with a general density distribution of n?R {sup –k} (where R is the radius) by considering thick-shell and thin-shell cases. A GRB afterglow with one smooth onset peak at early times is understood to result from such external shocks. Thus, we can determine the medium density distribution by fitting the onset peak appearing in the light curve of an early optical afterglow. We apply our model to 19 GRBs and find that their k values are in the range of 0.4-1.4, with a typical value of k ? 1, implying that this environment is neither a homogenous ISM with k = 0 nor a typical stellar wind with k = 2. This shows that the progenitors of these GRBs might have undergone a new mass-loss evolution.

  20. Mapping and Assessment of the United States Ocean Wave Energy Resource

    SciTech Connect (OSTI)

    Paul T. Jacobson; George Hagerman; George Scott

    2011-12-01T23:59:59.000Z

    This project estimates the naturally available and technically recoverable U.S. wave energy resources, using a 51-month Wavewatch III hindcast database developed especially for this study by National Oceanographic and Atmospheric Administration�¢����s (NOAA�¢����s) National Centers for Environmental Prediction. For total resource estimation, wave power density in terms of kilowatts per meter is aggregated across a unit diameter circle. This approach is fully consistent with accepted global practice and includes the resource made available by the lateral transfer of wave energy along wave crests, which enables wave diffraction to substantially reestablish wave power densities within a few kilometers of a linear array, even for fixed terminator devices. The total available wave energy resource along the U.S. continental shelf edge, based on accumulating unit circle wave power densities, is estimated to be 2,640 TWh/yr, broken down as follows: 590 TWh/yr for the West Coast, 240 TWh/yr for the East Coast, 80 TWh/yr for the Gulf of Mexico, 1570 TWh/yr for Alaska, 130 TWh/yr for Hawaii, and 30 TWh/yr for Puerto Rico. The total recoverable wave energy resource, as constrained by an array capacity packing density of 15 megawatts per kilometer of coastline, with a 100-fold operating range between threshold and maximum operating conditions in terms of input wave power density available to such arrays, yields a total recoverable resource along the U.S. continental shelf edge of 1,170 TWh/yr, broken down as follows: 250 TWh/yr for the West Coast, 160 TWh/yr for the East Coast, 60 TWh/yr for the Gulf of Mexico, 620 TWh/yr for Alaska, 80 TWh/yr for Hawaii, and 20 TWh/yr for Puerto Rico.

  1. Electron Beam Welding of a Depleted Uranium Alloy to Niobium Using a Calibrated Electron Beam Power Density Distribution

    SciTech Connect (OSTI)

    Elmer, J.W.; Teruya, A.T.; Terrill, P.E.

    2000-08-21T23:59:59.000Z

    Electron beam test welds were made joining flat plates of commercially pure niobium to a uranium-6wt%Nb (binary) alloy. The welding parameters and joint design were specifically developed to minimize mixing of the niobium with the U-6%Nb alloy. A Modified Faraday Cup (MFC) technique using computer-assisted tomography was employed to determine the precise power distribution of the electron beam so that the welding parameters could be directly transferred to other welding machines and/or to other facilities.

  2. Numerical simulations of acoustically generated gravitational waves at a first order phase transition

    E-Print Network [OSTI]

    Mark Hindmarsh; Stephan J. Huber; Kari Rummukainen; David J. Weir

    2015-04-13T23:59:59.000Z

    We present details of numerical simulations of the gravitational radiation produced by a first order {thermal} phase transition in the early universe. We confirm that the dominant source of gravitational waves is sound waves generated by the expanding bubbles of the low-temperature phase. We demonstrate that the sound waves have a power spectrum with power-law form between the scales set by the average bubble separation (which sets the length scale of the fluid flow $L_\\text{f}$) and the bubble wall width. The sound waves generate gravitational waves whose power spectrum also has a power-law form, at a rate proportional to $L_\\text{f}$ and the square of the fluid kinetic energy density. We identify a dimensionless parameter $\\tilde\\Omega_\\text{GW}$ characterising the efficiency of this "acoustic" gravitational wave production whose value is $8\\pi\\tilde\\Omega_\\text{GW} \\simeq 0.8 \\pm 0.1$ across all our simulations. We compare the acoustic gravitational waves with the standard prediction from the envelope approximation. Not only is the power spectrum steeper (apart from an initial transient) but the gravitational wave energy density is generically two orders of magnitude or more larger.

  3. MHK Technologies/New Knowledge Wind and Wave Renewable Mobile...

    Open Energy Info (EERE)

    Wave Renewable Mobile Wind and Wave Power Plant Platform < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage New Knowledge Wind and Wave Renewable...

  4. Aspects of Wave Turbulence in Preheating

    E-Print Network [OSTI]

    José A. Crespo; H. P. de Oliveira

    2014-06-04T23:59:59.000Z

    In this work we have studied the nonlinear preheating dynamics of the $\\frac{1}{4} \\lambda \\phi^4$ inflationary model. It is well established that after a linear stage of preheating characterized by the parametric resonance, the nonlinear dynamics becomes relevant driving the system towards turbulence. Wave turbulence is the appropriated description of this phase since matter distributions are fields instead of usual fluids. Therefore, turbulence develops due to the nonlinear interations of waves, here represented by the small inhomogeneities of the inflaton field. We present relevant aspects of wave turbulence such as the Kolmogorov-Zakharov spectrum in frequency and wave number domains that indicates that there are a transfer of energy through scales. From the power spectrum of the matter energy density we were able to estimate the temperature of the thermalized system.

  5. Ion acoustic waves in the plasma with the power-law q-distribution in nonextensive statistics

    E-Print Network [OSTI]

    Liyan, Liu

    2008-01-01T23:59:59.000Z

    We investigate the dispersion relation and Landau damping of ion acoustic waves in the collisionless magnetic-field-free plasma if it is described by the nonextensive q-distributions of Tsallis statistics. We show that the increased numbers of superthermal particles and low velocity particles can explain the strengthened and weakened modes of Landau damping, respectively, with the q-distribution. When the ion temperature is equal to the electron temperature, the weakly damped waves are found to be the distributions with small values of q.

  6. Bragg grating rogue wave

    E-Print Network [OSTI]

    Degasperis, Antonio; Aceves, Alejandro B

    2015-01-01T23:59:59.000Z

    We derive the rogue wave solution of the classical massive Thirring model, that describes nonlinear optical pulse propagation in Bragg gratings. Combining electromagnetically induced transparency with Bragg scattering four-wave mixing, may lead to extreme waves at extremely low powers.

  7. A deeper X-ray study of the core of the Perseus galaxy cluster: the power of sound waves and the distribution of metals and cosmic rays

    E-Print Network [OSTI]

    J. S. Sanders; A. C. Fabian

    2007-08-15T23:59:59.000Z

    We make a further study of the very deep Chandra observation of the X-ray brightest galaxy cluster, A426 in Perseus. We examine the radial distribution of energy flux inferred by the quasi-concentric ripples in surface brightness, assuming they are due to sound waves, and show that it is a significant fraction of the energy lost by radiative cooling within the inner 75-100 kpc, where the cooling time is 4-5 Gyr, respectively. The wave flux decreases outward with radius, consistent with energy being dissipated. Some newly discovered large ripples beyond 100 kpc, and a possible intact bubble at 170 kpc radius, may indicate a larger level of activity by the nucleus a few 100 Myr ago. The distribution of metals in the intracluster gas peaks at a radius of about 40 kpc and is significantly clumpy on scales of 5 kpc. The temperature distribution of the soft X-ray filaments and the hard X-ray emission component found within the inner 50 kpc are analysed in detail. The pressure due to the nonthermal electrons, responsible for a spectral component interpreted as inverse Compton emission, is high within 40 kpc of the centre and boosts the power in sound waves there; it drops steeply beyond 40 kpc. We find no thermal emission from the radio bubbles; in order for any thermal gas to have a filling factor within the bubbles exceeding 50 per cent, the temperature of that gas has to exceed 50 keV.

  8. The X-ray Power Density Spectrum of the Seyfert 2 Galaxy NGC 4945: Analysis and Application of the Method of Light Curve Simulations

    SciTech Connect (OSTI)

    Mueller, Martin; /SLAC

    2010-12-16T23:59:59.000Z

    The study of the power density spectrum (PDS) of fluctuations in the X-ray flux from active galactic nuclei (AGN) complements spectral studies in giving us a view into the processes operating in accreting compact objects. An important line of investigation is the comparison of the PDS from AGN with those from galactic black hole binaries; a related area of focus is the scaling relation between time scales for the variability and the black hole mass. The PDS of AGN is traditionally modeled using segments of power laws joined together at so-called break frequencies; associations of the break time scales, i.e., the inverses of the break frequencies, with time scales of physical processes thought to operate in these sources are then sought. I analyze the Method of Light Curve Simulations that is commonly used to characterize the PDS in AGN with a view to making the method as sensitive as possible to the shape of the PDS. I identify several weaknesses in the current implementation of the method and propose alternatives that can substitute for some of the key steps in the method. I focus on the complications introduced by uneven sampling in the light curve, the development of a fit statistic that is better matched to the distributions of power in the PDS, and the statistical evaluation of the fit between the observed data and the model for the PDS. Using archival data on one AGN, NGC 3516, I validate my changes against previously reported results. I also report new results on the PDS in NGC 4945, a Seyfert 2 galaxy with a well-determined black hole mass. This source provides an opportunity to investigate whether the PDS of Seyfert 1 and Seyfert 2 galaxies differ. It is also an attractive object for placement on the black hole mass-break time scale relation. Unfortunately, with the available data on NGC 4945, significant uncertainties on the break frequency in its PDS remain.

  9. Near-Region Modification of Total Pressure Fluctuations by a Normal Shock Wave in a Low-Density Hypersonic Wind Tunnel

    E-Print Network [OSTI]

    Mai, Chi Luong Nhat

    2014-05-01T23:59:59.000Z

    -density hypersonic wind tunnel. Measurements were obtained with a fast-response Pitot pressure probe traversing in the freestream direction. The tunnel freestream noise level was characterized and served as the inflow/upstream condition to the interaction...

  10. Scattering of radio frequency waves by blobs in tokamak plasmas

    SciTech Connect (OSTI)

    Ram, Abhay K. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)] [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Hizanidis, Kyriakos; Kominis, Yannis [School of Electrical and Computer Engineering, National Technical University of Athens, Association EURATOM-Hellenic Republic, Athens, GR-15773 (Greece)] [School of Electrical and Computer Engineering, National Technical University of Athens, Association EURATOM-Hellenic Republic, Athens, GR-15773 (Greece)

    2013-05-15T23:59:59.000Z

    The density fluctuations and blobs present in the edge region of magnetic fusion devices can scatter radio frequency (RF) waves through refraction, reflection, diffraction, and coupling to other plasma waves. This, in turn, affects the spectrum of the RF waves and the electromagnetic power that reaches the core of the plasma. The usual geometric optics analysis of RF scattering by density blobs accounts for only refractive effects. It is valid when the amplitude of the fluctuations is small, of the order of 10%, compared to the background density. In experiments, density fluctuations with much larger amplitudes are routinely observed, so that a more general treatment of the scattering process is needed. In this paper, a full-wave model for the scattering of RF waves by a blob is developed. The full-wave approach extends the range of validity well beyond that of geometric optics; however, it is theoretically and computationally much more challenging. The theoretical procedure, although similar to that followed for the Mie solution of Maxwell's equations, is generalized to plasmas in a magnetic field. Besides diffraction and reflection, the model includes coupling to a different plasma wave than the one imposed by the external antenna structure. In the model, it is assumed that the RF waves interact with a spherical blob. The plasma inside and around the blob is cold, homogeneous, and imbedded in a uniform magnetic field. After formulating the complete analytical theory, the effect of the blob on short wavelength electron cyclotron waves and longer wavelength lower hybrid waves is studied numerically.

  11. Design, characterization, and modeling of GaN based HFETs for millimeter wave and microwave power amplifier applications

    E-Print Network [OSTI]

    Conway, Adam M.

    2006-01-01T23:59:59.000Z

    power GaN electronics thermally resistive substrates,” IEEE400um SiC (Si, GaN, Sapphire, Diamond) substrate 5um Au 50umfree standing GaN or SiC substrates). At room temperature,

  12. Cycloidal Wave Energy Converter

    SciTech Connect (OSTI)

    Stefan G. Siegel, Ph.D.

    2012-11-30T23:59:59.000Z

    This program allowed further advancing the development of a novel type of wave energy converter, a Cycloidal Wave Energy Converter or CycWEC. A CycWEC consists of one or more hydrofoils rotating around a central shaft, and operates fully submerged beneath the water surface. It operates under feedback control sensing the incoming waves, and converts wave power to shaft power directly without any intermediate power take off system. Previous research consisting of numerical simulations and two dimensional small 1:300 scale wave flume experiments had indicated wave cancellation efficiencies beyond 95%. The present work was centered on construction and testing of a 1:10 scale model and conducting two testing campaigns in a three dimensional wave basin. These experiments allowed for the first time for direct measurement of electrical power generated as well as the interaction of the CycWEC in a three dimensional environment. The Atargis team successfully conducted two testing campaigns at the Texas A&M Offshore Technology Research Center and was able to demonstrate electricity generation. In addition, three dimensional wave diffraction results show the ability to achieve wave focusing, thus increasing the amount of wave power that can be extracted beyond what was expected from earlier two dimensional investigations. Numerical results showed wave cancellation efficiencies for irregular waves to be on par with results for regular waves over a wide range of wave lengths. Using the results from previous simulations and experiments a full scale prototype was designed and its performance in a North Atlantic wave climate of average 30kW/m of wave crest was estimated. A full scale WEC with a blade span of 150m will deliver a design power of 5MW at an estimated levelized cost of energy (LCOE) in the range of 10-17 US cents per kWh. Based on the new results achieved in the 1:10 scale experiments these estimates appear conservative and the likely performance at full scale will exceed this initial performance estimates. In advancing the Technology Readiness Level (TRL) of this type of wave energy converter from 3 to 4, we find the CycWEC to exceed our initial estimates in terms of hydrodynamic performance. Once fully developed and optimized, it has the potential to not just outperform all other WEC technologies, but to also deliver power at a lower LCOE than competing conventional renewables like wind and solar. Given the large wave power resource both domestically and internationally, this technology has the potential to lead to a large improvement in our ability to produce clean electricity at affordable cost.

  13. Power Electronics and Electrical Drives Prof. Dr.-Ing. Joachim Bcker

    E-Print Network [OSTI]

    Hellebrand, Sybille

    High power and torque densities High power and torque densities Research Topics PMSM / IPMSM Modeling

  14. Constraining the gravitational wave energy density of the Universe in the Range 0.1 Hz to 1 Hz using the Apollo Seismic Array

    E-Print Network [OSTI]

    Coughlin, Michael

    2014-01-01T23:59:59.000Z

    In this paper, we describe an analysis of Apollo era lunar seismic data that places an upper limit on an isotropic stochastic gravitational-wave background integrated over a year in the frequency range 0.1\\,Hz -- 1\\,Hz. We find that because the Moon's ambient noise background is much quieter than that of the Earth, significant improvements over an Earth based analysis were made. We find an upper limit of $\\Omega_{\\rm GW}<1.2\\times 10^{5}$, which is three orders of magnitude smaller than a similar analysis of a global network of broadband seismometers on Earth and the best limits in this band to date. We also discuss the benefits of a potential Earth-Moon correlation search and compute the time-dependent overlap reduction function required for such an analysis. For this search, we find an upper limit an order of magnitude larger than the Moon-Moon search.

  15. Constraining the gravitational wave energy density of the Universe in the Range 0.1 Hz to 1 Hz using the Apollo Seismic Array

    E-Print Network [OSTI]

    Michael Coughlin; Jan Harms

    2014-10-11T23:59:59.000Z

    In this paper, we describe an analysis of Apollo era lunar seismic data that places an upper limit on an isotropic stochastic gravitational-wave background integrated over a year in the frequency range 0.1\\,Hz -- 1\\,Hz. We find that because the Moon's ambient noise background is much quieter than that of the Earth, significant improvements over an Earth based analysis were made. We find an upper limit of $\\Omega_{\\rm GW}<1.2\\times 10^{5}$, which is three orders of magnitude smaller than a similar analysis of a global network of broadband seismometers on Earth and the best limits in this band to date. We also discuss the benefits of a potential Earth-Moon correlation search and compute the time-dependent overlap reduction function required for such an analysis. For this search, we find an upper limit an order of magnitude larger than the Moon-Moon search.

  16. Nonlinear Electron Heat Conduction Equation and Self similar method for 1-D Thermal Waves in Laser Heating of Solid Density DT Fuel

    E-Print Network [OSTI]

    A. Mohammadian Pourtalari; M. A. Jafarizadeh; M. Ghoranneviss

    2011-11-23T23:59:59.000Z

    Electron heat conduction is one of the ways that energy transports in laser heating of fusible target material. The aim of Inertial Confinement Fusion (ICF) is to show that the thermal conductivity is strongly dependent on temperature and the equation of electron heat conduction is a nonlinear equation. In this article, we solve the one-dimensional (1-D) nonlinear electron heat conduction equation with a self-similar method (SSM). This solution has been used to investigate the propagation of 1-D thermal wave from a deuterium-tritium (DT) plane source which occurs when a giant laser pulse impinges onto a DT solid target. It corresponds to the physical problem of rapid heating of a boundary layer of material in which the energy of laser pulse is released in a finite initial thickness.

  17. Energy Transfer via Solar Wind Driven Ultra Low Frequency Waves in the Earth's Magnetosphere

    E-Print Network [OSTI]

    Hartinger, Michael David

    2012-01-01T23:59:59.000Z

    spectral density comparison Wave polarization and energyEnergy transfer via MHD waves . . . . . . . . . . . . .magnetosphere (where wave energy can exit the magnetosphere

  18. Sonolytic destruction of methyl tert-butyl ether by ultrasonic irradiation: The role of O{sub 3}, H{sub 2}O{sub 2}, frequency, and power density

    SciTech Connect (OSTI)

    Kang, J.W.; Hung, H.M.; Lin, A.; Hoffmann, M.R. [California Inst. of Tech., Pasadena, CA (United States). W.M. Keck Labs.] [California Inst. of Tech., Pasadena, CA (United States). W.M. Keck Labs.

    1999-09-15T23:59:59.000Z

    The kinetics of degradation of methyl tert-butyl ether (MTBE) by ultrasonic irradiation in the presence of ozone as functions of applied frequencies and applied power are investigated. Experiments are performed over the frequency range of 205--1,078 kHz. The higher overall reaction rates are observed at 358 and 618 kHz and then at 205 and 1,078 kHz. The observed pseudo-first-order rate constant, k{sub 0}, for MTBE degradation increases with increasing power density up to 250 W L{sup {minus}1}. A linear dependence of the first-order rate constant, k{sub O{sub 3}}, for the simultaneous degradation of O{sub 3} on power density is also observed. Naturally occurring organic matter (NOM) is shown to have a negligible effect on observed reaction rates.

  19. Gravity Waves Gravity Waves

    E-Print Network [OSTI]

    Weijgaert, Rien van de

    ;14/03/2014 6 H L H L L Phase & Group Velocity #12;14/03/2014 7 Doppler Effect #12;14/03/2014 8 Shock Waves #12;14/03/2014 14 Supernova Remnant Cassiopeia A Supernova blast waves #12;14/03/2014 15 Tycho's Remnant (SN 1572AD A SNR flythrough Theory of Supernova Blast Waves Supernovae: Type Ia Subsonic deflagration wave turning

  20. Excitation of dust acoustic waves by an ion beam in a plasma cylinder with negatively charged dust grains

    SciTech Connect (OSTI)

    Sharma, Suresh C. [Department of Applied Physics, Delhi Technological University (DTU), Shahbad Daulatpur, Bawana Road, Delhi-42 (India); Kaur, Daljeet [Department of Physics, Guru Teg Bahadur Institute of Technology, Rajouri Garden, New Delhi (India); Gahlot, Ajay [Department of Physics, Maharaja Surajmal Institute of Technology, Janakpuri, New Delhi (India); Sharma, Jyotsna [Department of Physics, KIIT College of Engineering, Bhondsi Gurgaon 122102 (India)

    2014-10-15T23:59:59.000Z

    An ion beam propagating through a plasma cylinder having negatively charged dust grains drives a low frequency electrostatic dust acoustic wave (DAW) to instability via Cerenkov interaction. The unstable wave frequencies and the growth rate increase with the relative density of negatively charged dust grains. The growth rate of the unstable mode scales to the one-third power of the beam density. The real part of the frequency of the unstable mode increases with the beam energy and scales to almost one-half power of the beam energy. The phase velocity, frequency, and wavelength results of the unstable mode are in compliance with the experimental observations.

  1. One-dimensional full wave simulation on XB mode conversion in electron cyclotron heating

    SciTech Connect (OSTI)

    Kim, S. H., E-mail: shkim95@kaeri.re.kr [Korea Atomic Energy Research Institute, Daejeon 305-353 (Korea, Republic of); Lee, H. Y.; Jo, J. G.; Hwang, Y. S. [Seoul National University, Seoul 151-742 (Korea, Republic of)

    2014-06-15T23:59:59.000Z

    The XB mode conversion in electron cyclotron resonance frequency heating has been studied in detail through 1D full wave simulation. The field pattern depends on the density scale length, and the wave absorption near upper hybrid resonance is maximized beyond the R(X) mode cutoff density for optimized density scale length. The simulated mode conversion efficiency has been compared with that of an analytic formula, showing good agreements except for the phase dependent term of the X wave. The mode conversion efficiency is calculated for oblique injections as well, and it is found that the efficiency decreases as the injection angles increases. Short magnetic field scale length is confirmed to relax the short density scale length condition maximizing the XB mode conversion efficiency. Finally, the simulation code is used to analyze the mode conversion and power absorption of a pre-ionization plasma in versatile experiment spherical torus.

  2. The Wirewalker: A Vertically Profiling Instrument Carrier Powered by Ocean Waves R. PINKEL, M. A. GOLDIN, J. A. SMITH, O. M. SUN, A. A. AJA, M. N. BUI, AND T. HUGHEN

    E-Print Network [OSTI]

    Smith, Jerome A.

    The Wirewalker: A Vertically Profiling Instrument Carrier Powered by Ocean Waves R. PINKEL, M. A­time record. The elements of the WW system in- clude a surface buoy, a wire suspended from the buoy, a weight at the end of the wire, and the profiler itself. The wire and weight follow the surface motion of the buoy

  3. Detection of lower hybrid waves in the scrape-off layer of tokamak plasmas with microwave backscattering

    SciTech Connect (OSTI)

    Baek, S. G., E-mail: sgbaek@mit.edu; Shiraiwa, S.; Parker, R. R.; Bonoli, P. T.; Marmar, E. S.; Wallace, G. M.; Lau, C. [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States)] [MIT Plasma Science and Fusion Center, Cambridge, Massachusetts 02139 (United States); Dominguez, A.; Kramer, G. J. [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)] [Princeton Plasma Physics Laboratory, Princeton, New Jersey 08543 (United States)

    2014-01-15T23:59:59.000Z

    Microwave backscattering experiments have been performed on the Alcator C-Mod tokamak in order to investigate the propagation of lower hybrid (LH) waves in reactor-relevant, high-density plasmas. When the line-averaged density is raised above 1?×?10{sup 20} m{sup –3}, lower hybrid current drive efficiency is found to be lower than expected [Wallace et al., Phys. Plasmas 19, 062505 (2012)] and LH power is thought to be dissipated at the plasma edge. Using a single channel (60 GHz) ordinary-mode (O-mode) reflectometer system, we demonstrate radially localized LH wave measurements in the scrape-off layer of high density plasmas (n{sup ¯}{sub e}???0.9×10{sup 20}?m{sup ?3}). Measured backscattered O-mode power varies depending on the magnetic field line mapping, suggesting the resonance cone propagation of LH waves. Backscattered power is also sensitive to variations in plasma density and the launched parallel refractive index of the LH waves. LH ray-tracing simulations have been carried out to interpret the observed variations. To understand the measured LH waves in regions not magnetically connected to the launcher, two hypotheses are examined. One is the weak single pass absorption and the other is scattering of LH waves by non-linear effects.

  4. The Second Peak: The Dark-Energy Density and the Cosmic Microwave Background

    E-Print Network [OSTI]

    Marc Kamionkowski; Ari Buchalter

    2000-01-05T23:59:59.000Z

    Supernova evidence for a negative-pressure dark energy (e.g., cosmological constant or quintessence) that contributes a fraction $\\Omega_\\Lambda\\simeq0.7$ of closure density has been bolstered by the discrepancy between the total density, $\\Omega_{\\rm tot}\\simeq1$, suggested by the location of the first peak in the cosmic microwave background (CMB) power spectrum and the nonrelativistic-matter density $\\Omega_m\\simeq0.3$ obtained from dynamical measurements. Here we show that the impending identification of the location of the {\\it second} peak in the CMB power spectrum will provide an immediate and independent probe of the dark-energy density. As an aside, we show how the measured height of the first peak probably already points toward a low matter density and places upper limits to the reionization optical depth and gravitational-wave amplitude.

  5. Binding Energy of dº Transition Metals to Alkenes By Wave...

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

    Energy of dº Transition Metals to Alkenes By Wave Function Theory and Density Functional Theory. Binding Energy of dº Transition Metals to Alkenes By Wave Function Theory...

  6. Electron Bernstein Wave Studies in MST

    SciTech Connect (OSTI)

    Seltzman, Andrew H.; Anderson, Jay K.; Nonn, Paul D.; Kauffold, Jason X.; Forest, Cary B. [University of Wisconsin-Madison, Dept. Of Physics, 1150 University Ave., Madison, WI 53706 (United States); Diem, Stephanie J. [Oak Ridge National Laboratory, 1 Bethel Valley Road, Oak Ridge, TN 37831 (United States)

    2011-12-23T23:59:59.000Z

    The overdense plasma in an RFP prevents electromagnetic waves from propagating past the edge, however use of the electron Bernstein wave (EBW) has the potential to heat and drive current in the plasma. MHD simulations have demonstrated that resistive tearing mode stability is very sensitive to gradients in the edge current density profile allowing EBW to potentially be a stabilizing influence. A new MW level experiment is being commissioned on MST to evaluate the potential use of the EBW for current profile control on the RFP. The development of new equipment includes a 5.5 GHz klystron driven by a novel switchmode power supply. A quartz window has been constructed and coupling with a cylindrical molybdenum wave guide antenna has been studied. Due to the steep edge density gradient in the RFP, it is possible to efficiently couple to the EBW with O or X mode launch. The EBW is strongly damped at the electron cyclotron resonance where it couples to the electron gyromotion and alters the electron distribution. Either Fisch-Boozer or Ohkawa current drive mechanisms can be activated to drive off axis current in the plasma. Preliminary experiments have been performed to verify high power coupling and understand heating via observed x-ray emission when compared to Fokker-Plank modeling in CQL3D.

  7. Numerical simulations of acoustically generated gravitational waves at a first order phase transition

    E-Print Network [OSTI]

    Hindmarsh, Mark; Rummukainen, Kari; Weir, David J

    2015-01-01T23:59:59.000Z

    We present details of numerical simulations of the gravitational radiation produced by a first order {thermal} phase transition in the early universe. We confirm that the dominant source of gravitational waves is sound waves generated by the expanding bubbles of the low-temperature phase. We demonstrate that the sound waves have a power spectrum with power-law form between the scales set by the average bubble separation (which sets the length scale of the fluid flow $L_\\text{f}$) and the bubble wall width. The sound waves generate gravitational waves whose power spectrum also has a power-law form, at a rate proportional to $L_\\text{f}$ and the square of the fluid kinetic energy density. We identify a dimensionless parameter $\\tilde\\Omega_\\text{GW}$ characterising the efficiency of this "acoustic" gravitational wave production whose value is $8\\pi\\tilde\\Omega_\\text{GW} \\simeq 0.8 \\pm 0.1$ across all our simulations. We compare the acoustic gravitational waves with the standard prediction from the envelope appr...

  8. Green Power Purchasing

    Broader source: Energy.gov [DOE]

    Eligible resources include tidal and wave power, fuel cells using renewable fuels, hydropower facilities less than 60 megawatts (MW), solar thermal-electric systems, photovoltaics (PV), wind,...

  9. Propagating Waves in a Monolayer of Gas-Fluidized Rods

    E-Print Network [OSTI]

    L. J. Daniels; D. J. Durian

    2010-11-12T23:59:59.000Z

    We report on an observation of propagating compression waves in a quasi-two-dimensional monolayer of apolar granular rods fluidized by an upflow of air. The collective wave speed is an order of magnitude faster than the speed of the particles. This gives rise to anomalously large number fluctuations dN ~ $N^{0.72 \\pm 0.04}$, which are greater than ordinary number fluctuations of N^{1/2}. We characterize the waves by calculating the spatiotemporal power spectrum of the density. The position of observed peaks, as a function of frequency w and wavevector k, yields a linear dispersion relationship in the long-time, long-wavelength limit and a wavespeed c = w/k. Repeating this analysis for systems at different densities and air speeds, we observe a linear increase in the wavespeed with increasing packing fraction with no dependence on the airflow. Although air-fluidized rods self-propel individually or in dilute collections, the parallel and perpendicular root-mean-square speeds of the rods indicate that they no longer self-propel when propagating waves are present. Based on this mutual exclusivity, we map out the phase behavior for the existence of waves vs self-propulsion as a function of density and fluidizing airflow.

  10. Green Power Purchase Plan

    Broader source: Energy.gov [DOE]

    Class I renewable energy resources include solar, wind, new sustainable biomass, landfill gas, fuel cells (using renewable or non-renewable fuels), ocean thermal power, wave or tidal power, low...

  11. The Centre for Power Transmission

    E-Print Network [OSTI]

    Burton, Geoffrey R.

    The Centre for Power Transmission and Motion Control Centre for PTMC Department of Mechanical) 1225 38-6371 Email: ptmc@bath.ac.uk Web: http://www.bath.ac.uk/ptmc/ Consultancy Project WAVE POWER SYSTEM SIMULATIONS Power take-off systems Wave power take-off systems are an exciting new development

  12. DISCOVERY OF SMALL-SCALE SPIRAL STRUCTURES IN THE DISK OF SAO 206462 (HD 135344B): IMPLICATIONS FOR THE PHYSICAL STATE OF THE DISK FROM SPIRAL DENSITY WAVE THEORY

    SciTech Connect (OSTI)

    Muto, T.; Takeuchi, T. [Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro, Tokyo 152-8551 (Japan); Grady, C. A. [Eureka Scientific, 2452 Delmer, Suite 100, Oakland CA 96002 (United States); Hashimoto, J. [National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Fukagawa, M. [Department of Earth and Space Science, Graduate School of Science, Osaka University, 1-1, Machikaneyama, Toyonaka, Osaka 560-0043 (Japan); Hornbeck, J. B. [Department of Physics and Astronomy, University of Louisville, Louisville, KY 40292 (United States); Sitko, M. [Space Science Institute, 4750 Walnut St., Suite 205, Boulder, CO 80301 (United States); Russell, R. [The Aerospace Corporation, Los Angeles, CA 90009 (United States); Werren, C. [Department of Physics, University of Cincinnati, Cincinnati, OH 45221-0011 (United States); Cure, M. [Departamento de Fisica y Astronomia, Universidad de Valparaiso, Avda. Gran Bretana 1111, Casilla 5030, Valparaiso (Chile); Currie, T. [ExoPlanets and Stellar Astrophysics Laboratory, Code 667, Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Ohashi, N. [Institute of Astronomy and Astrophysics, Academia Sinica, P.O. Box 23-141, Taipei 106, Taiwan (China); Okamoto, Y.; Momose, M. [College of Science, Ibaraki University, 2-1-1 Bunkyo, Mito, Ibaraki 310-8512 (Japan); Honda, M. [Department of Information Science, Kanagawa University, 2946 Tsuchiya, Hiratsuka, Kanagawa 259-1293 (Japan); Inutsuka, S. [Department of Physics, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8602 (Japan); Dong, R.; Brandt, T. [Department of Astrophysical Sciences, Princeton University, NJ08544 (United States); Abe, L. [Laboratoire Lagrange, UMR7293, Universite de Nice-Sophia Antipolis, CNRS, Observatoire de la Cote d'Azur, 06300 Nice (France); Brandner, W., E-mail: muto@geo.titech.ac.jp [Max Planck Institute for Astronomy, Heidelberg (Germany); and others

    2012-04-01T23:59:59.000Z

    We present high-resolution, H-band imaging observations, collected with Subaru/HiCIAO, of the scattered light from the transitional disk around SAO 206462 (HD 135344B). Although previous sub-mm imagery suggested the existence of a dust-depleted cavity at r {<=} 46 AU, our observations reveal the presence of scattered light components as close as 0.''2 ({approx} 28 AU) from the star. Moreover, we have discovered two small-scale spiral structures lying within 0.''5 ({approx} 70 AU). We present models for the spiral structures using the spiral density wave theory, and derive a disk aspect ratio of h {approx} 0.1, which is consistent with previous sub-mm observations. This model can potentially give estimates of the temperature and rotation profiles of the disk based on dynamical processes, independently from sub-mm observations. It also predicts the evolution of the spiral structures, which can be observable on timescales of 10-20 years, providing conclusive tests of the model. While we cannot uniquely identify the origin of these spirals, planets embedded in the disk may be capable of exciting the observed morphology. Assuming that this is the case, we can make predictions on the locations and, possibly, the masses of the unseen planets. Such planets may be detected by future multi-wavelength observations.

  13. Comparison between Gaussian-type orbitals and plane wave ab initio density functional theory modeling of layer silicates: Talc [Mg{sub 3}Si{sub 4}O{sub 10}(OH){sub 2}] as model system

    SciTech Connect (OSTI)

    Ulian, Gianfranco; Valdrè, Giovanni, E-mail: giovanni.valdre@unibo.it [Dipartimento di Scienze Biologiche e Geologico-Ambientali, Centro di Ricerca Interdisciplinare di Biomineralogia, Cristallografia e Biomateriali, Università di Bologna “Alma Mater Studiorum” Piazza di Porta San Donato 1, 40126 Bologna (Italy)] [Dipartimento di Scienze Biologiche e Geologico-Ambientali, Centro di Ricerca Interdisciplinare di Biomineralogia, Cristallografia e Biomateriali, Università di Bologna “Alma Mater Studiorum” Piazza di Porta San Donato 1, 40126 Bologna (Italy); Tosoni, Sergio [Departament de Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, C/ Martí i Franquès 1, E-08028 Barcelona (Spain)] [Departament de Química Física and Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, C/ Martí i Franquès 1, E-08028 Barcelona (Spain)

    2013-11-28T23:59:59.000Z

    The quantum chemical characterization of solid state systems is conducted with many different approaches, among which the adoption of periodic boundary conditions to deal with three-dimensional infinite condensed systems. This method, coupled to the Density Functional Theory (DFT), has been proved successful in simulating a huge variety of solids. Only in relatively recent years this ab initio quantum-mechanic approach has been used for the investigation of layer silicate structures and minerals. In the present work, a systematic comparison of different DFT functionals (GGA-PBEsol and hybrid B3LYP) and basis sets (plane waves and all-electron Gaussian-type orbitals) on the geometry, energy, and phonon properties of a model layer silicate, talc [Mg{sub 3}Si{sub 4}O{sub 10}(OH){sub 2}], is presented. Long range dispersion is taken into account by DFT+D method. Results are in agreement with experimental data reported in literature, with minimal deviation given by the GTO/B3LYP-D* method regarding both axial lattice parameters and interaction energy and by PW/PBE-D for the unit-cell volume and angular values. All the considered methods adequately describe the experimental talc infrared spectrum.

  14. 3rd International Symposium on Advanced Fluid/Solid Science and Technology in Experimental Mechanics, 7-10 December. 2008, Tainan, Taiwan Detection of wave propagation by a nonstationary cross-spectral density technique

    E-Print Network [OSTI]

    Texas at Arlington, University of

    Mechanics, 7-10 December. 2008, Tainan, Taiwan Detection of wave propagation by a nonstationary cross for the propagation time, and was applied to a shock and a detonation wave. The results show that by including prone to error than the cross-correlation technique. Key words Wave propagation, Cross-spectrum, Time

  15. Thompson/Ocean 420/Winter 2005 Surface Gravity Wave Surface Gravity Wave Generation

    E-Print Network [OSTI]

    Thompson, LuAnne

    the wavelength. Wind energy in Waves Wave energy out (breaking) #12;Thompson/Ocean 420/Winter 2005 Surface waves with different periods and phases. The spectrum of energy is usually plotted as energy density, (unit of energy/unit frequency interval, Hz). The energy density is given by the amount of energy

  16. Gravitational wave radiometry: Mapping a stochastic gravitational wave background

    SciTech Connect (OSTI)

    Mitra, Sanjit [Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411007 (India); Observatoire de la Cote d'Azur, BP 4229, 06304 Nice Cedex 4 (France); Dhurandhar, Sanjeev; Souradeep, Tarun [Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411007 (India); Lazzarini, Albert; Mandic, Vuk; Ballmer, Stefan [LIGO Laboratory, California Institute of Technology, MS 18-34, Pasadena, California 91125 (United States); Bose, Sukanta [Department of Physics, Washington State University, Pullman, Washington 99164-2814 (United States)

    2008-02-15T23:59:59.000Z

    The problem of the detection and mapping of a stochastic gravitational wave background (SGWB), either cosmological or astrophysical, bears a strong semblance to the analysis of the cosmic microwave background (CMB) anisotropy and polarization, which too is a stochastic field, statistically described in terms of its correlation properties. An astrophysical gravitational wave background (AGWB) will likely arise from an incoherent superposition of unmodelled and/or unresolved sources and cosmological gravitational wave backgrounds (CGWB) are also predicted in certain scenarios. The basic statistic we use is the cross correlation between the data from a pair of detectors. In order to ''point'' the pair of detectors at different locations one must suitably delay the signal by the amount it takes for the gravitational waves (GW) to travel to both detectors corresponding to a source direction. Then the raw (observed) sky map of the SGWB is the signal convolved with a beam response function that varies with location in the sky. We first present a thorough analytic understanding of the structure of the beam response function using an analytic approach employing the stationary phase approximation. The true sky map is obtained by numerically deconvolving the beam function in the integral (convolution) equation. We adopt the maximum likelihood framework to estimate the true sky map using the conjugate gradient method that has been successfully used in the broadly similar, well-studied CMB map-making problem. We numerically implement and demonstrate the method on signal generated by simulated (unpolarized) SGWB for the GW radiometer consisting of the LIGO pair of detectors at Hanford and Livingston. We include 'realistic' additive Gaussian noise in each data stream based on the LIGO-I noise power spectral density. The extension of the method to multiple baselines and polarized GWB is outlined. In the near future the network of GW detectors, including the Advanced LIGO and Virgo detectors that will be sensitive to sources within a thousand times larger spatial volume, could provide promising data sets for GW radiometry.

  17. Quantum coherent switch utilizing commensurate nanoelectrode and charge density periodicities

    DOE Patents [OSTI]

    Harrison; Neil (Santa Fe, NM), Singleton; John (Los Alamos, NM), Migliori; Albert (Santa Fe, NM)

    2008-08-05T23:59:59.000Z

    A quantum coherent switch having a substrate formed from a density wave (DW) material capable of having a periodic electron density modulation or spin density modulation, a dielectric layer formed onto a surface of the substrate that is orthogonal to an intrinsic wave vector of the DW material; and structure for applying an external spatially periodic electrostatic potential over the dielectric layer.

  18. Density modification by two superposing TE{sub 10} modes in a plasma filled rectangular waveguide

    SciTech Connect (OSTI)

    Tomar, Sanjay K.; Malik, Hitendra K. [Plasma Waves and Particle Acceleration Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110 016 (India)] [Plasma Waves and Particle Acceleration Laboratory, Department of Physics, Indian Institute of Technology Delhi, New Delhi 110 016 (India)

    2013-07-15T23:59:59.000Z

    Microwave and plasma interaction is examined via two fundamental TE{sub 10} modes propagating in a plasma filled rectangular waveguide after superposing at a smaller angle. The propagation of the resultant mode realized from these two modes is governed by a wave equation obtained using the Maxwell's equations. This equation is solved numerically using fourth order Runge-Kutta method for the field amplitude of the microwave in the waveguide considering the waveguide to be made up of a perfect conductor and filled with different types of initial plasma density distributions, viz. homogeneous density, linear density with gradient in the propagation direction, and the density with Gaussian profile along the waveguide width. A phenomenon similar to the duct formation by high power microwaves is found to take place, where the plasma density attains interesting profiles. These profiles can be controlled by the angle of superposition, phase difference between the fields of the two modes, microwave frequency and microwave field amplitude.

  19. Sandia Energy - Advanced Controls of Wave Energy Converters May...

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

    WEC designs efficiently produce power only within a narrow wave frequency range. Advanced control of the power-conversion chain can alter this paradigm. Models have shown...

  20. Nonlinear dust acoustic waves and shocks

    SciTech Connect (OSTI)

    Merlino, R. L.; Heinrich, J. R.; Hyun, S.-H.; Meyer, J. K. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52242 (United States)

    2012-05-15T23:59:59.000Z

    We describe experiments on (1) nonlinear dust acoustic waves and (2) dust acoustic shocks performed in a direct current (DC) glow discharge dusty plasma. First, we describe experiments showing nonlinear dust acoustic waves characterized by waveforms of the dust density that are typically sharper in the wave crests and flatter in the wave troughs (compared to sinusoidal waves), indicating the development of wave harmonics. We discuss this behavior in terms of a second-order fluid theory for dust acoustic waves. Second, experimental observations of the propagation and steepening of large-amplitude dust acoustic waves into dust acoustic shock waves are presented. The observed shock wave evolution is compared with numerical calculations based on the Riemann solution of the fully nonlinear fluid equations for dust acoustic waves.

  1. Pauling bond strength, bond length and electron density distribution...

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

    Pauling bond strength, bond length and electron density distribution. Pauling bond strength, bond length and electron density distribution. Abstract: A power law regression...

  2. A Comprehensive Study Of Fracture Patterns And Densities In The...

    Open Energy Info (EERE)

    Patterns And Densities In The Geysers Geothermal Reservoir Using Microearthquake Shear-Wave Splitting Tomography Jump to: navigation, search OpenEI Reference LibraryAdd to library...

  3. Spectral broadening measurement of the lower hybrid waves during long pulse operation in Tore Supra

    SciTech Connect (OSTI)

    Berger-By, G.; Decampy, J.; Goniche, M.; Ekedahl, A.; Delpech, L.; Leroux, F. [CEA, IRFM, F-13108 Saint-Paul-lez-Durance (France); Antar, G. Y. [American University of Beirut, Riad el-Solh, Beirut 1107-2020 (Lebanon); Collaboration: Tore Supra Team

    2014-02-12T23:59:59.000Z

    On many tokamaks (C-Mod, EAST, FTU, JET, HT-7, TS), a decrease in current drive efficiency of the Lower Hybrid (LH) waves is observed in high electron density plasmas. The cause of this behaviour is believed to be: Parametric Instabilities (PI) and Scattering from Density Fluctuations (SDF). For the ITER LH system, our knowledge must be improved to avoid such effects and to maintain the LH current drive efficiency at high density. The ITPA IOS group coordinates this effort [1] and all experimental data are essential to validate the numerical codes in progress. Usually the broadening of the LH wave frequency spectrum is measured by a probe located in the plasma edge. For this study, the frequency spectrum of a reflected power signal from the LH antenna was used. In addition, the spectrum measurements are compared with the density fluctuations observed on RF probes located at the antenna mouth. Several plasma currents (0.6 to 1.4 MA) and densities up to 5.2 × 10{sup 19} m?3 have been realised on Tore Supra (TS) long pulses and with high injected RF power, up to 5.4 MW-30s. This allowed using a spectrum analyser to make several measurements during the plasma pulse. The side lobe amplitude, shifted by 20-30MHz with respect to the main peak, grows with increasing density. Furthermore, for an increase of plasma current at the same density, the spectra broaden and become asymmetric. Some parametric dependencies are shown in this paper.

  4. Wave Energy Resources Representative Sites Around the Hawaiian Islands

    E-Print Network [OSTI]

    Flux p14 Appendix A ­ SWAN Numerical Model Calibration with NOAA/NDBO Buoys p21 #12;Wave Power. Vega Ph.D October 11, 2010 #12;Wave Power Resources off the Hawaiian Islands October 11, 2010 1 of Contents Summary p2 Background: Wave Power Conversion p3 Licensing and Permitting p3 Challenges

  5. Sandia National Laboratories: wave energy converter

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

    release. This model has ... Sandia Funded to Model Power Pods for Utility-Scale Wave-Energy Converter On September 16, 2014, in Computational Modeling & Simulation, Energy,...

  6. Energy in density gradient

    E-Print Network [OSTI]

    Vranjes, J

    2015-01-01T23:59:59.000Z

    Inhomogeneous plasmas and fluids contain energy stored in inhomogeneity and they naturally tend to relax into lower energy states by developing instabilities or by diffusion. But the actual amount of energy in such inhomogeneities has remained unknown. In the present work the amount of energy stored in a density gradient is calculated for several specific density profiles in a cylindric configuration. This is of practical importance for drift wave instability in various plasmas, and in particular in its application in models dealing with the heating of solar corona because the instability is accompanied with stochastic heating, so the energy contained in inhomogeneity is effectively transformed into heat. It is shown that even for a rather moderate increase of the density at the axis in magnetic structures in the corona by a factor 1.5 or 3, the amount of excess energy per unit volume stored in such a density gradient becomes several orders of magnitude greater than the amount of total energy losses per unit ...

  7. Tunable Laser Plasma Accelerator based on Longitudinal Density Tailoring

    SciTech Connect (OSTI)

    Gonsalves, Anthony; Nakamura, Kei; Lin, Chen; Panasenko, Dmitriy; Shiraishi, Satomi; Sokollik, Thomas; Benedetti, Carlo; Schroeder, Carl; Geddes, Cameron; Tilborg, Jeroen van; Osterhoff, Jens; Esarey, Eric; Toth, Csaba; Leemans, Wim

    2011-07-15T23:59:59.000Z

    Laser plasma accelerators have produced high-quality electron beams with GeV energies from cm-scale devices and are being investigated as hyperspectral fs light sources producing THz to {gamma}-ray radiation and as drivers for future high-energy colliders. These applications require a high degree of stability, beam quality and tunability. Here we report on a technique to inject electrons into the accelerating field of a laser-driven plasma wave and coupling of this injector to a lower-density, separately tunable plasma for further acceleration. The technique relies on a single laser pulse powering a plasma structure with a tailored longitudinal density profile, to produce beams that can be tuned in the range of 100-400 MeV with percent-level stability, using laser pulses of less than 40 TW. The resulting device is a simple stand-alone accelerator or the front end for a multistage higher-energy accelerator.

  8. Using a Bore-Soliton-Splash to understand Rogue Waves, Tsunamis & Wave Energy

    E-Print Network [OSTI]

    Wirosoetisno, Djoko

    )compression] use wave focussing in a convergence [3]. · IPS wave buoy has a linear dynamo below sea level. · Designed & built new RogueWavEnergy device: it works, a LED is blinking & we measured the power output. 8

  9. The Loudest Gravitational Wave Events

    E-Print Network [OSTI]

    Hsin-Yu Chen; Daniel E. Holz

    2014-09-04T23:59:59.000Z

    As first emphasized by Bernard Schutz, there exists a universal distribution of signal-to-noise ratios for gravitational wave detection. Because gravitational waves (GWs) are almost impossible to obscure via dust absorption or other astrophysical processes, the strength of the detected signal is dictated solely by the emission strength and the distance to the source. Assuming that the space density of an arbitrary population of GW sources does not evolve, we show explicitly that the distribution of detected signal-to-noise (SNR) values depends solely on the detection threshold; it is independent of the detector network (interferometer or pulsar timing array), the individual detector noise curves (initial or Advanced LIGO), the nature of the GW sources (compact binary coalescence, supernova, or some other discrete source), and the distributions of source variables (only non-spinning neutron stars of mass exactly $1.4\\,M_\\odot$ or a complicated distribution of masses and spins). We derive the SNR distribution for each individual detector within a network as a function of the relative detector orientations and sensitivities. While most detections will have SNR near the detection threshold, there will be a tail of events to higher SNR. We derive the SNR distribution of the loudest (highest SNR) events in any given sample of detections. We find that the median SNR of the loudest out of the first four events should have an $\\mbox{SNR}=22$ (for a threshold of 12, appropriate for the Advanced LIGO/Virgo network), increasing to a median value for the loudest SNR of 47 for 40 detections. We expect these loudest events to provide particularly powerful constraints on their source parameters, and they will play an important role in extracting astrophysics from gravitational wave sources. These distributions also offer an important internal calibration of the response of the GW detector networks.

  10. Application of wave generator theory to the development of a Wave Energy Converter

    E-Print Network [OSTI]

    Wood, Stephen L.

    of the second buoy's curved face. Upon deployment, the WEC successfully logged the power output of the system a wave energy converter (WEC) capable of providing at least a quarter-Watt of power to a small aquatic and basic wave generation technology to improving the power capture design of a basic direct drive WEC

  11. 314 IEEE MICROWAVE AND GUIDED WAVE LETTERS, VOL. 9, NO. 8, AUGUST 1999 39-GHz GaN-Based Microwave Power

    E-Print Network [OSTI]

    York, Robert A.

    314 IEEE MICROWAVE AND GUIDED WAVE LETTERS, VOL. 9, NO. 8, AUGUST 1999 3­9-GHz GaN-Based Microwave. P. Keller, and U. K. Mishra, Fellow, IEEE Abstract--We present an initial demonstration of GaN-band network. Using 0.7-m gate-length GaN high-electron-mobility transistors (HEMT's) with current

  12. Traveling-wave photodetector

    DOE Patents [OSTI]

    Hietala, V.M.; Vawter, G.A.

    1993-12-14T23:59:59.000Z

    The traveling-wave photodetector of the present invention combines an absorptive optical waveguide and an electrical transmission line, in which optical absorption in the waveguide results in a photocurrent at the electrodes of the electrical transmission line. The optical waveguide and electrical transmission line of the electrically distributed traveling-wave photodetector are designed to achieve matched velocities between the light in the optical waveguide and electrical signal generated on the transmission line. This velocity synchronization provides the traveling-wave photodetector with a large electrical bandwidth and a high quantum efficiency, because of the effective extended volume for optical absorption. The traveling-wave photodetector also provides large power dissipation, because of its large physical size. 4 figures.

  13. PowerPoint Presentation

    Broader source: Energy.gov (indexed) [DOE]

    Research Center Blvd. Fayetteville, AR 72701 Phone: (479)-443-5759 Email: marcelo@apei.net Website: www.apei.net High Temperature and High Power Density SiC Power Electronic...

  14. PowerPoint Presentation

    Broader source: Energy.gov (indexed) [DOE]

    Research Center Blvd. Fayetteville, AR 72701 Phone: (479)-443-5759 Email: mschupb@apei.net Website: www.apei.net High Power Density Silicon Carbide Power Electronic Converters...

  15. Generation of Gaussian Density Fields

    E-Print Network [OSTI]

    Hugo Martel

    2005-07-15T23:59:59.000Z

    This document describes analytical and numerical techniques for the generation of Gaussian density fields, which represent cosmological density perturbations. The mathematical techniques involved in the generation of density harmonics in k-space, the filtering of the density fields, and the normalization of the power spectrum to the measured temperature fluctuations of the Cosmic Microwave Background, are presented in details. These techniques are well-known amongst experts, but the current literature lacks a formal description. I hope that this technical report will prove useful to new researchers moving into this field, sparing them the task of reinventing the wheel.

  16. Production of highly unidirectional lower-hybrid waves

    SciTech Connect (OSTI)

    McWilliams, R.; Okubo, M.; Platt, R.C.; Sheehan, D.P.

    1985-01-01T23:59:59.000Z

    The development of a highly unidirectional lower-hybrid wave source would improve the electron current drive efficiency in tokamaks. Lower-hybrid waves launched from a phased wave array are shown to be reflected from a grid placed in a cold, low-density plasma. The antenna--grid combination results in highly unidirectional lower-hybrid waves.

  17. Ultra high vacuum broad band high power microwave window

    DOE Patents [OSTI]

    Nguyen-Tuong, Viet (Seaford, VA); Dylla, III, Henry Frederick (Yorktown, VA)

    1997-01-01T23:59:59.000Z

    An improved high vacuum microwave window has been developed that utilizes high density polyethylene coated on two sides with SiOx, SiNx, or a combination of the two. The resultant low dielectric and low loss tangent window creates a low outgassing, low permeation seal through which broad band, high power microwave energy may be passed. No matching device is necessary and the sealing technique is simple. The features of the window are broad band transmission, ultra-high vacuum compatibility with a simple sealing technique, low voltage standing wave ratio, high power transmission and low cost.

  18. Ultra high vacuum broad band high power microwave window

    DOE Patents [OSTI]

    Nguyen-Tuong, V.; Dylla, H.F. III

    1997-11-04T23:59:59.000Z

    An improved high vacuum microwave window has been developed that utilizes high density polyethylene coated on two sides with SiOx, SiNx, or a combination of the two. The resultant low dielectric and low loss tangent window creates a low outgassing, low permeation seal through which broad band, high power microwave energy may be passed. No matching device is necessary and the sealing technique is simple. The features of the window are broad band transmission, ultra-high vacuum compatibility with a simple sealing technique, low voltage standing wave ratio, high power transmission and low cost. 5 figs.

  19. Traveling wave device for combining or splitting symmetric and asymmetric waves

    DOE Patents [OSTI]

    Möbius, Arnold (Eggenstein, DE); Ives, Robert Lawrence (Saratoga, CA)

    2005-07-19T23:59:59.000Z

    A traveling wave device for the combining or splitting of symmetric and asymmetric traveling wave energy includes a feed waveguide for traveling wave energy, the feed waveguide having an input port and a launching port, a reflector for coupling wave energy between the feed waveguide and a final waveguide for the collection and transport of wave energy to or from the reflector. The power combiner has a launching port for symmetrical waves which includes a cylindrical section coaxial to the feed waveguide, and a launching port for asymmetric waves which includes a sawtooth rotated about a central axis.

  20. Low density metal hydride foams

    DOE Patents [OSTI]

    Maienschein, Jon L. (Oakland, CA); Barry, Patrick E. (Pleasant Hill, CA)

    1991-01-01T23:59:59.000Z

    Disclosed is a low density foam having a porosity of from 0 to 98% and a density less than about 0.67 gm/cc, prepared by heating a mixture of powered lithium hydride and beryllium hydride in an inert atmosphere at a temperature ranging from about 455 to about 490 K for a period of time sufficient to cause foaming of said mixture, and cooling the foam thus produced. Also disclosed is the process of making the foam.

  1. High Energy Density Capacitors

    SciTech Connect (OSTI)

    None

    2010-07-01T23:59:59.000Z

    BEEST Project: Recapping is developing a capacitor that could rival the energy storage potential and price of today’s best EV batteries. When power is needed, the capacitor rapidly releases its stored energy, similar to lightning being discharged from a cloud. Capacitors are an ideal substitute for batteries if their energy storage capacity can be improved. Recapping is addressing storage capacity by experimenting with the material that separates the positive and negative electrodes of its capacitors. These separators could significantly improve the energy density of electrochemical devices.

  2. Theory of heating of hot magnetized plasma by Alfven waves. Application for solar corona

    E-Print Network [OSTI]

    T. M. Mishonov; M. V. Stoev; Y. G. Maneva

    2007-02-13T23:59:59.000Z

    The heating of magnetized plasma by propagation of Alfven waves is calculated as a function of the magnetic field spectral density. The results can be applied to evaluate the heating power of the solar corona at known data from satellites' magnetometers. This heating rate can be incorporated in global models for heating of the solar corona and creation of the solar wind. The final formula for the heating power is illustrated with a model spectral density of the magnetic field obtained by analysis of the Voyager 1 mission results. The influence of high frequency dissipative modes is also taken into account and it is concluded that for evaluation of the total coronal heating it is necessary to know the spectral density of the fluctuating component of the magnetic field up to the frequency of electron-proton collisions.

  3. Plasma control by modification of helicon wave propagation in low magnetic fields

    SciTech Connect (OSTI)

    Lafleur, T.; Charles, C.; Boswell, R. W. [Space Plasma, Power and Propulsion Group, Research School of Physics and Engineering, Australian National University, Canberra, Australian Capital Territory 0200 (Australia)

    2010-07-15T23:59:59.000Z

    By making use of nonuniform magnetic fields, it is shown experimentally that control of helicon wave propagation can be achieved in a low pressure (0.08 Pa) expanding plasma. The m=1 helicon waves are formed during a direct capacitive to wave mode transition that occurs in a low diverging magnetic field (B{sub 0}<3 mT). In this initial configuration, waves are prevented from reaching the downstream region, but slight modifications to the magnetic field allows the axial distance over which waves can propagate to be controlled. By changing the effective propagation distance in this way, significant modification of the density and plasma potential profiles can be achieved, showing that the rf power deposition can be spatially controlled as well. Critical to the modification of the wave propagation behavior is the magnetic field strength (and geometry) near the exit of the plasma source region, which gives electron cyclotron frequencies close to the wave frequency of 13.56 MHz.

  4. Ocean Wave Converters: State of the Art and Current Status

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    and benefits have been identified in the area of ocean wave energy extraction, i.e., harnessing the wave [3]. To harness the power energy in waves present a different set of technical challenges and a wide, this paper presents ocean wave energy fundamentals and then reviews the fundamental concepts and the main

  5. CONTROL OF POPULATION DENSITIES SURROUNDING NUCLEAR POWER PLANTS. VOLUME 5 OF THE FINAL REPORT ON HEALTH AND SAFETY IMPACTS OF NUCLEAR, GEOTHERMAL, AND FOSSIL-FUEL ELECTRIC GENERATION IN CALIFORNIA

    E-Print Network [OSTI]

    Nero, jA.V.

    2010-01-01T23:59:59.000Z

    Standards for Nuclear Power Plants," by A.V. Nero and Y.C.Planning for Nuclear Power Plants in California," by W.W.S.Surrounding Nuclear Power Plants," by A.V. Nero, C.H.

  6. Power Factor Reactive Power

    E-Print Network [OSTI]

    motor power: 117.7 V x 5.1 A = 600 W? = 0.6 kW? NOT the power measured by meter #12;Page 9 PSERC: displacement power factor: angle between voltage and current = 0 degrees pf = cos(0 degrees) = 1.0 true powerPage 1 PSERC Power Factor and Reactive Power Ward Jewell Wichita State University Power Systems

  7. Vacuum Waves

    E-Print Network [OSTI]

    Paul S. Wesson

    2012-12-11T23:59:59.000Z

    As an example of the unification of gravitation and particle physics, an exact solution of the five-dimensional field equations is studied which describes waves in the classical Einstein vacuum. While the solution is essentially 5D in nature, the waves exist in ordinary 3D space, and may provide a way to test for an extra dimension.

  8. Texas Tech Effort Overview Collaborative Research on Novel High Power

    E-Print Network [OSTI]

    Anlage, Steven

    N) · Nonlinear Transmission lines · High Power Microwave source development · High reprate rf sources · HPM wave Power Microwave breakdown · Vacuum UV Spectroscopy in atmospheric gases · Explosively driven HPM

  9. Matter Wave Radiation Leading to Matter Teleportation

    E-Print Network [OSTI]

    Yong-Yi Huang

    2015-02-12T23:59:59.000Z

    The concept of matter wave radiation is put forward, and its equation is established for the first time. The formalism solution shows that the probability density is a function of displacement and time. A free particle and a two-level system are reinvestigated considering the effect of matter wave radiation. Three feasible experimental designs, especially a modified Stern-Gerlach setup, are proposed to verify the existence of matter wave radiation. Matter wave radiation effect in relativity has been formulated in only a raw formulae, which offers another explanation of Lamb shift. A possible mechanics of matter teleportation is predicted due to the effect of matter wave radiation.

  10. On the origin of solar wind. Alfven waves induced jump of coronal temperature

    E-Print Network [OSTI]

    T. M. Mishonov; M. V. Stoev; Y. G. Maneva

    2007-06-06T23:59:59.000Z

    Absorbtion of Alfven waves is considered to be the main mechanism of heating in the solar corona. It is concluded that the sharp increase of the plasma temperature by two orders of magnitude is related to a self-induced opacity with respect to Alfven waves. The maximal frequency for propagation of Alfven waves is determined by the strongly temperature dependent kinematic viscosity. In such a way the temperature jump is due to absorption of high frequency Alfven waves in a narrow layer above the solar surface. It is calculated that the power per unit area dissipated in this layer due to damping of Alfven waves blows up the plasma and gives birth to the solar wind. A model short wave-length (WKB) evaluation takes into account the 1/f^2 frequency dependance of the transversal magnetic field and velocity spectral densities. Such spectral densities agree with old magnetometric data taken by Voyager 1 and recent theoretical calculations in the framework of Langevin-Burgers MHD. The present theory predicts existence of intensive high frequency MHD Alfven waves in the cold layer beneath the corona. It is briefly discussed how this statement can be checked experimentally. It is demonstrated that the magnitude of the Alfven waves generating random noise and the solar wind velocity can be expressed only in terms of satellite experimental data. It is advocated that investigation of properties of the solar surface as a random driver by optical methods is an important task for future solar physics. Jets of accretion disks are speculated as a special case of the wind from magnetized turbulent plasma.

  11. Development of PTO-Sim: A Power Performance Module for the Open-Source Wave Energy Converter Code WEC-Sim

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOEThe Bonneville Power AdministrationField Campaign: Potential Application toDevelopingandDevelopment ofNovel

  12. Nonlinear interaction of proton whistler with kinetic Alfvén wave to study solar wind turbulence

    SciTech Connect (OSTI)

    Goyal, R.; Sharma, R. P. [Centre for Energy Studies, Indian Institute of Technology, Delhi-110016 (India)] [Centre for Energy Studies, Indian Institute of Technology, Delhi-110016 (India); Goldstein, M. L. [NASA Goddard Space Flight Centre, Code 673, Greenbelt, Maryland 20771 (United States)] [NASA Goddard Space Flight Centre, Code 673, Greenbelt, Maryland 20771 (United States); Dwivedi, N. K. [Austrian Academy of Sciences, Space Research Institute, Schmiedlstrasse 6, 8042 Graz (Austria)] [Austrian Academy of Sciences, Space Research Institute, Schmiedlstrasse 6, 8042 Graz (Austria)

    2013-12-15T23:59:59.000Z

    This paper presents the nonlinear interaction between small but finite amplitude kinetic Alfvén wave (KAW) and proton whistler wave using two-fluid model in intermediate beta plasma, applicable to solar wind. The nonlinearity is introduced by modification in the background density. This change in density is attributed to the nonlinear ponderomotive force due to KAW. The solutions of the model equations, governing the nonlinear interaction (and its effect on the formation of localized structures), have been obtained using semi-analytical method in solar wind at 1AU. It is concluded that the KAW properties significantly affect the threshold field required for the filament formation and their critical size (for proton whistler). The magnetic and electric field power spectra have been obtained and their relevance with the recent observations of solar wind turbulence by Cluster spacecraft has been pointed out.

  13. Riding the Clean Energy Wave: New Projects Aim to Improve Water...

    Broader source: Energy.gov (indexed) [DOE]

    Riding the Clean Energy Wave: New Projects Aim to Improve Water Power Devices Riding the Clean Energy Wave: New Projects Aim to Improve Water Power Devices April 16, 2014 - 1:56pm...

  14. Irregular wave induced velocities in shallow water

    E-Print Network [OSTI]

    Sultan, Nels John

    1991-01-01T23:59:59.000Z

    probabil- ity density function. This thesis applies this expanded distribution to fluid particle velocities instead of wave elevations. Ochi (1982) presents a review of recent ad- vances in the stochastic analysis of random seas. He notes that the first..., (Longuet-Higgins 1963), that purely linear waves will have a Gaussian distribu- tion. Therefore, any deviation from a Gaussian distribution must be attributed to wave nonlinearities. Ochi (1982) discusses a series of experiments by Honda and Mitsuyasu...

  15. Nonlinear inertial Alfven wave in dusty plasmas

    SciTech Connect (OSTI)

    Mahmood, S. [Theoretical Plasma Physics Division, P.O. Nilore Islamabad 44000 (Pakistan); National Center for Physics, Shadra Valley, Quaid-i-Azam University Islamabad 44000 (Pakistan); Saleem, H. [National Center for Physics, Shadra Valley, Quaid-i-Azam University Islamabad 44000 (Pakistan)

    2011-11-29T23:59:59.000Z

    Solitary inertial Alfven wave in the presence of positively and negatively charged dust particles is studied. It is found that electron density dips are formed in the super Alfvenic region and wave amplitude is increased for the case of negatively charged dust particles in comparison with positively charged dust particles in electron-ion plasmas.

  16. On the Energy of Rotating Gravitational Waves

    E-Print Network [OSTI]

    Bahram Mashhoon; James C. McClune; Enrique Chavez; Hernando Quevedo

    1996-09-06T23:59:59.000Z

    A class of solutions of the gravitational field equations describing vacuum spacetimes outside rotating cylindrical sources is presented. A subclass of these solutions corresponds to the exterior gravitational fields of rotating cylindrical systems that emit gravitational radiation. The properties of these rotating gravitational wave spacetimes are investigated. In particular, we discuss the energy density of these waves using the gravitational stress-energy tensor.

  17. PPPL-3195 -Preprint: May 1996, UC-426, 427 INVESTIGATION OF LOWER HYBRID WAVE DAMPING

    E-Print Network [OSTI]

    of the spatial distribution of the superthermal electrons, which can be used to monitor the wave power deposition

  18. PPPL3195 Preprint: May 1996, UC426, 427 INVESTIGATION OF LOWER HYBRID WAVE DAMPING

    E-Print Network [OSTI]

    of the spatial distribution of the superthermal electrons, which can be used to monitor the wave power deposition

  19. Sandia National Laboratories: WEC power conversion chain

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

    Computational Modeling & Simulation, Energy, News, News & Events, Partnership, Renewable Energy, Water Power Although ocean waves represent an enormous energy resource, most...

  20. Tweedie Family Densities: Methods of Evaluation

    E-Print Network [OSTI]

    Smyth, Gordon K.

    of Queensland, St Lucia, Q 4072, Australia. 2 University of Southern Queensland, Toowoomba, Q 4350, Australia. Tweedie family densities are characterised by power variance functions of the form V[µ] = µp , where p

  1. Wave represents displacement Wave represents pressure Source -Sound Waves

    E-Print Network [OSTI]

    Colorado at Boulder, University of

    Wave represents displacement Wave represents pressure Source - Sound Waves Distance between crests is wavelength Number of crests passing a point in 1 second is frequency Wave represents pressure Target - Radio Waves Distance between crests is wavelength Number of crests passing a point in 1 second is frequency

  2. Sandia Energy - Sandia, NREL Release Wave Energy Converter Modeling...

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

    Sandia, NREL Release Wave Energy Converter Modeling and Simulation Code: WEC-Sim Home Renewable Energy Energy Water Power Partnership News News & Events Computational Modeling &...

  3. DOE Announces Webinars on the Wave Energy Converter Prize, the...

    Broader source: Energy.gov (indexed) [DOE]

    24: Live Webinar on the Administration of the Wave Energy Converter Prize Funding Opportunity Announcement Webinar Sponsor: EERE Water Power Program The Energy Department will...

  4. Electron Bernstein Wave Heating and Emission in the TCV Tokamak

    E-Print Network [OSTI]

    Petitpierre, Claude

    1 Electron Bernstein Wave Heating and Emission in the TCV Tokamak A. Mueck 1 , Y. Camenen 1 , S density tokamak plasmas is limited due to reflections of the waves at so-called wave cut-offs. Electron for the first time via the O-X- B mode conversion process in a standard aspect-ratio tokamak. The results

  5. Structural vibration damping using lightweight, low-wave-speed media

    E-Print Network [OSTI]

    Verdirame, Justin Matthew, 1978-

    2007-01-01T23:59:59.000Z

    Incorporation of a low-density, low-wave-speed medium (LWSM) into a structure yields significant damping if the speed of wave propagation in the medium is low enough for standing waves to arise in it. In this thesis, we ...

  6. E-Print Network 3.0 - alpha-u charge density Sample Search Results

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

    University of Florida Collection: Physics 31 Conducting Polymer Nanotubes toward Supercapacitor Ran Liu and Sang Bok Lee* Summary: density, power density values of the...

  7. Spin waves in the (

    SciTech Connect (OSTI)

    Lipscombe, O. J. [University of Tennessee, Knoxville (UTK); Chen, G. F. [The Institute of Physics, Chinese Academy of Sciences; Fang, Chen [Purdue University; Perring, T. G. [ISIS Facility, Rutherford Appleton Laboratory; Abernathy, Douglas L [ORNL; Christianson, Andrew D [ORNL; Egami, Takeshi [ORNL; Wang, Nanlin [The Institute of Physics, Chinese Academy of Sciences; Hu, Jiangping [Purdue University and Chinese Academy of Sciences; Dai, Pengcheng [University of Tennessee, Knoxville (UTK)

    2011-01-01T23:59:59.000Z

    We use neutron scattering to show that spin waves in the iron chalcogenide Fe{sub 1.05}Te display novel dispersion clearly different from both the first principles density functional calculations and recent observations in the related iron pnictide CaFe{sub 2}As{sub 2}. By fitting to a Heisenberg Hamiltonian, we find that although the nearest-neighbor exchange couplings in the two systems are quite different, their next-nearest-neighbor (NNN) couplings are similar. This suggests that superconductivity in the pnictides and chalcogenides share a common magnetic origin that is intimately associated with the NNN magnetic coupling between the irons.

  8. The Wave Function and Quantum Reality

    E-Print Network [OSTI]

    Shan Gao

    2011-08-04T23:59:59.000Z

    We investigate the meaning of the wave function by analyzing the mass and charge density distribution of a quantum system. According to protective measurement, a charged quantum system has mass and charge density proportional to the modulus square of its wave function. It is shown that the mass and charge density is not real but effective, and it is formed by the ergodic motion of a localized particle with the total mass and charge of the system. Moreover, it is argued that the ergodic motion is not continuous but discontinuous and random. This result suggests a new interpretation of the wave function, according to which the wave function is a description of random discontinuous motion of particles, and the modulus square of the wave function gives the probability density of the particles being in certain locations. It is shown that the suggested interpretation of the wave function disfavors the de Broglie-Bohm theory and the many-worlds interpretation but favors the dynamical collapse theories, and the random discontinuous motion of particles may provide an appropriate random source to collapse the wave function.

  9. Engineering Density of States of Earth Abundant Semiconductors...

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

    of States of Earth Abundant Semiconductors for Enhanced Thermoelectric Power Factor Engineering Density of States of Earth Abundant Semiconductors for Enhanced Thermoelectric...

  10. Radiative precursors driven by converging blast waves in noble gases

    SciTech Connect (OSTI)

    Burdiak, G. C.; Lebedev, S. V.; Harvey-Thompson, A. J.; Swadling, G. F.; Suzuki-Vidal, F.; Hall, G. N.; Khoory, E.; Pickworth, L.; Bland, S. N.; Grouchy, P. de; Skidmore, J.; Suttle, L.; Bennett, M.; Niasse, N. P. L. [Blackett Laboratory, Imperial College London SW7 2BW (United Kingdom)] [Blackett Laboratory, Imperial College London SW7 2BW (United Kingdom); Williams, R. J. R. [Atomic Weapons Establishment, Aldermaston RG7 4PR (United Kingdom)] [Atomic Weapons Establishment, Aldermaston RG7 4PR (United Kingdom); Blesener, K.; Atoyan, L.; Cahill, A.; Hoyt, C.; Potter, W. [Laboratory of Plasma Studies, Cornell University, Ithaca, New York 14853 (United States)] [Laboratory of Plasma Studies, Cornell University, Ithaca, New York 14853 (United States); and others

    2014-03-15T23:59:59.000Z

    A detailed study of the radiative precursor that develops ahead of converging blast waves in gas-filled cylindrical liner z-pinch experiments is presented. The experiment is capable of magnetically driving 20?km s{sup ?1} blast waves through gases of densities of the order 10{sup ?5} g cm{sup ?3} (see Burdiak et al. [High Energy Density Phys. 9(1), 52–62 (2013)] for a thorough description). Data were collected for Ne, Ar, and Xe gas-fills. The geometry of the setup allows a determination of the plasma parameters both in the precursor and across the shock, along a nominally uniform line of sight that is perpendicular to the propagation of the shock waves. Radiation from the shock was able to excite NeI, ArII, and XeII/XeIII precursor spectral features. It is shown that the combination of interferometry and optical spectroscopy data is inconsistent with upstream plasmas being in LTE. Specifically, electron density gradients do not correspond to any apparent temperature change in the emission spectra. Experimental data are compared to 1D radiation hydrodynamics HELIOS-CR simulations and to PrismSPECT atomic physics calculations to assist in a physical interpretation of the observations. We show that upstream plasma is likely in the process of being radiatively heated and that the emission from a small percentage of ionised atoms within a cool background plasma dominates the emission spectra. Experiments were carried out on the MAGPIE and COBRA pulsed-power facilities at Imperial College London and Cornell University, respectively.

  11. The parametric decay of Alfven waves into shear Alfven waves and dust lower hybrid waves

    SciTech Connect (OSTI)

    Jamil, M. [Department of Physics, Government College University, Lahore 54000 (Pakistan); Department of Physics, Crescent Model School Shadman, Lahore 54000 (Pakistan); Shah, H. A.; Zubia, K.; Zeba, I.; Uzma, Ch. [Department of Physics, Government College University, Lahore 54000 (Pakistan); Salimullah, M. [Department of Physics, Government College University, Lahore 54000 (Pakistan); Department of Physics, Jahangirnagar University, Savar, Dhaka 1342 (Bangladesh)

    2010-07-15T23:59:59.000Z

    The parametric decay instability of Alfven wave into low-frequency electrostatic dust-lower-hybrid and electromagnetic shear Alfven waves has been investigated in detail in a dusty plasma in the presence of external/ambient uniform magnetic field. Magnetohydrodynamic fluid equations of plasmas have been employed to find the linear and nonlinear response of the plasma particles for this three-wave nonlinear coupling in a dusty magnetoplasma. Here, relatively high frequency electromagnetic Alfven wave has been taken as the pump wave. It couples with other two low-frequency internal possible modes of the dusty magnetoplasma, viz., the dust-lower-hybrid and shear Alfven waves. The nonlinear dispersion relation of the dust-lower-hybrid wave has been solved to obtain the growth rate of the parametric decay instability. The growth rate is maximum for small value of external magnetic field B{sub s}. It is noticed that the growth rate is proportional to the unperturbed electron number density n{sub oe}.

  12. Power Plant Power Plant

    E-Print Network [OSTI]

    Tingley, Joseph V.

    Basin Center for Geothermal Energy at University of Nevada, Reno (UNR) 2 Nevada Geodetic LaboratoryStillwater Power Plant Wabuska Power Plant Casa Diablo Power Plant Glass Mountain Geothermal Area Lassen Geothermal Area Coso Hot Springs Power Plants Lake City Geothermal Area Thermo Geothermal Area

  13. Freak waves in white dwarfs and magnetars

    SciTech Connect (OSTI)

    Sabry, R. [Theoretical Physics Group, Physics Department, Faculty of Science, Damietta University, New Damietta 34517 (Egypt); Department of Physics, College of Science and Humanitarian Studies, Salman bin Abdulaziz University, Alkharj (Saudi Arabia); International Centre for Advanced Studies in Physical Sciences, Faculty of Physics and Astronomy, Ruhr University Bochum, D-44780 Bochum (Germany); Moslem, W. M. [International Centre for Advanced Studies in Physical Sciences, Faculty of Physics and Astronomy, Ruhr University Bochum, D-44780 Bochum (Germany); Department of Physics, Faculty of Science, Port Said University, Port Said (Egypt); Centre for Theoretical Physics, The British University in Egypt (BUE), El-Shorouk City, Cairo (Egypt); Shukla, P. K. [International Centre for Advanced Studies in Physical Sciences, Faculty of Physics and Astronomy, Ruhr University Bochum, D-44780 Bochum (Germany); Department of Mechanical and Aerospace Engineering and Center for Energy Research, University of California, San Diego, La Jolla, California 92093 (United States)

    2012-12-15T23:59:59.000Z

    We report properties of ion acoustic freak waves that propagate in a plasma composed of warm ions and ultrarelativistic electrons and positrons. The dynamics of the nonlinear freak waves is governed by the nonlinear Schroedinger equation. The possible region for the freak waves to exist is defined precisely for typical parameters of white dwarfs and magnetars corona. It is found that for low wave number, the nonlinear ion-acoustic wave packets are structurally stable in magnetars corona than in white dwarfs. However, for large wave numbers the situation is opposite. The critical wave number threshold (k{sub c}), which indicates where the modulational instability sets in, is defined for both applications. It is seen that near to k{sub c} the freak wave amplitude becomes high, but it decreases whenever we stepped away from k{sub c}. For the wave numbers close to k{sub c}, the increase of the unperturbed density ratio of positrons-to-electrons ({beta}) would lead to increase the freak wave amplitude, but for larger wave numbers the amplitude decreases with the increase of {beta}.

  14. Wave energy attenuation and shoreline alteration characteristics of submerged breakwaters

    E-Print Network [OSTI]

    Krafft, Katherine Margaret

    1993-01-01T23:59:59.000Z

    - frequency X ? distance from original shoreline, (assuming a constant slope of 1: 15) Xt - centered and padded time series data CHAPTER I INTRODUCTION 1. 1 General The dynamic behavior of waves on a shore in conjunction with inadequate littoral drift... periodogram, the asymptotically unbiased estimate of the spectral density function, the centered and padded data, time, wave frequency, The relationship between the incident wave spectrum, S;(m), and the transmitted wave spectrum, St(w), can...

  15. A KINETIC MODEL OF SOLAR WIND GENERATION BY OBLIQUE ION-CYCLOTRON WAVES

    SciTech Connect (OSTI)

    Isenberg, Philip A.; Vasquez, Bernard J. [Institute for the Study of Earth, Oceans and Space and Department of Physics, University of New Hampshire, Durham, NH 03824 (United States)

    2011-04-20T23:59:59.000Z

    The fast solar wind is generated by extended perpendicular ion heating in coronal holes, but the kinetic mechanism responsible for this heating has not been determined. One long-standing possibility is the resonant-cyclotron dissipation of ion-cyclotron waves, replenished from a turbulent cascade of interacting counter-propagating Alfven waves. We present results of a kinetic model for proton heating by the quasilinear resonant-cyclotron wave-particle interaction in a coronal hole. The resonant wave spectrum is taken as a power law in wavenumber, uniformly distributed in propagation direction between 0 deg. and 60 deg. with respect to the large-scale radial magnetic field. We obtain the steady-state solution of the kinetic guiding-center equation for the proton distribution in an expanding coronal hole, including the effects of large-scale forces of gravity, charge-separation electric field, Alfven wave ponderomotive force, and mirror force, along with the small-scale scattering from the wave dissipation. We find that plausible wave intensities can yield reasonable flow speeds and temperatures in the heliocentric radial range between 2 and 6 solar radii. We address the claim in earlier work that dissipation of parallel-propagating ion-cyclotron waves cannot provide enough acceleration and show that claim to be incorrect. We find that the combined action of the large-scale forces and the resonant-cyclotron scattering produces proton distribution functions with a characteristic structure: compressed in the sunward half of velocity space with a high-density shell separate from the origin, and relatively expanded in the anti-sunward half of velocity space. We suggest that qualitatively similar proton distributions would result from the kinetic evolution of any sufficiently effective perpendicular heating mechanism operating in an expanding coronal hole.

  16. Ultra-Micro Wave Rotor Investigations Florin Iancu, Janusz Piechna*

    E-Print Network [OSTI]

    Müller, Norbert

    Nowowiejska Str., 00-665 Warsaw, Poland Abstract Ultra Micro Gas Turbines (UµGT) are expected to be a next of incorporating a wave rotor to an ultra-micro gas turbine and the advantages of wave rotors, topping gas turbines at about 70%. Keywords: PowerMEMS, wave rotor, ultra micro gas turbine, pressure exchanger, efficiency 1

  17. Nonlinear coupling of left and right handed circularly polarized dispersive Alfvén wave

    SciTech Connect (OSTI)

    Sharma, R. P., E-mail: rpsharma@ces.iitd.ac.in; Sharma, Swati, E-mail: swati.sharma704@gmail.com; Gaur, Nidhi, E-mail: nidhiphysics@gmail.com [Centre for Energy Studies, Indian Institute of Technology Delhi, New Delhi 110016 (India)

    2014-07-15T23:59:59.000Z

    The nonlinear phenomena are of prominent interests in understanding the particle acceleration and transportation in the interplanetary space. The ponderomotive nonlinearity causing the filamentation of the parallel propagating circularly polarized dispersive Alfvén wave having a finite frequency may be one of the mechanisms that contribute to the heating of the plasmas. The contribution will be different of the left (L) handed mode, the right (R) handed mode, and the mix mode. The contribution also depends upon the finite frequency of the circularly polarized waves. In the present paper, we have investigated the effect of the nonlinear coupling of the L and R circularly polarized dispersive Alfvén wave on the localized structures formation and the respective power spectra. The dynamical equations are derived in the presence of the ponderomotive nonlinearity of the L and R pumps and then studied semi-analytically as well as numerically. The ponderomotive nonlinearity accounts for the nonlinear coupling between both the modes. In the presence of the adiabatic response of the density fluctuations, the nonlinear dynamical equations satisfy the modified nonlinear Schrödinger equation. The equations thus obtained are solved in solar wind regime to study the coupling effect on localization and the power spectra. The effect of coupling is also studied on Faraday rotation and ellipticity of the wave caused due to the difference in the localization of the left and the right modes with the distance of propagation.

  18. MHD Wave Propagation in the Neighbourhood of Two Null Points

    E-Print Network [OSTI]

    J. A. McLaughlin; A. W. Hood

    2007-12-11T23:59:59.000Z

    The nature of fast magnetoacoustic and Alfv\\'en waves is investigated in a zero $\\beta$ plasma in the neighbourhood of a pair of two-dimensional null points. This gives an indication of wave propagation in the low $\\beta$ solar corona, for a more complicated magnetic configuration than that looked at by McLaughlin & Hood (2004). It is found that the fast wave is attracted to the null points and that the front of the wave slows down as it approaches the null point pair, with the wave splitting and part of the wave accumulating at one null and the rest at the other. Current density will then accumulate at these points and ohmic dissipation will then extract the energy in the wave at these points. This suggests locations where wave heating will occur in the corona. The Alfv\\'en wave behaves in a different manner in that the wave accumulates along the separatrices. Hence, the current density will accumulate at this part of the topology and this is where wave heating will occur. However, the phenomenon of wave accumulation at a specific place is a feature of both wave types, and illustrates the importance of studying the topology of the corona when considering MHD wave propagation.

  19. Structural power flow measurement

    SciTech Connect (OSTI)

    Falter, K.J.; Keltie, R.F.

    1988-12-01T23:59:59.000Z

    Previous investigations of structural power flow through beam-like structures resulted in some unexplained anomalies in the calculated data. In order to develop structural power flow measurement as a viable technique for machine tool design, the causes of these anomalies needed to be found. Once found, techniques for eliminating the errors could be developed. Error sources were found in the experimental apparatus itself as well as in the instrumentation. Although flexural waves are the carriers of power in the experimental apparatus, at some frequencies longitudinal waves were excited which were picked up by the accelerometers and altered power measurements. Errors were found in the phase and gain response of the sensors and amplifiers used for measurement. A transfer function correction technique was employed to compensate for these instrumentation errors.

  20. Zero Energy of Plane-Waves for ELKOs

    E-Print Network [OSTI]

    Luca Fabbri

    2011-02-23T23:59:59.000Z

    We consider the ELKO field in interaction through contorsion with its own spin density, and we investigate the form of the consequent autointeractions; to do so we take into account the high-density limit and find plane wave solutions: such plane waves give rise to contorsional autointeractions for which the Ricci metric curvature vanishes and therefore the energy density is equal to zero identically. Consequences are discussed.

  1. WindWaveFloat Final Report

    SciTech Connect (OSTI)

    Alla Weinstein, Dominique Roddier, Kevin Banister

    2012-03-30T23:59:59.000Z

    Principle Power Inc. and National Renewable Energy Lab (NREL) have completed a contract to assess the technical and economic feasibility of integrating wave energy converters into the WindFloat, resulting in a new concept called the WindWaveFloat (WWF). The concentration of several devices on one platform could offer a potential for both economic and operational advantages. Wind and wave energy converters can share the electrical cable and power transfer equipment to transport the electricity to shore. Access to multiple generation devices could be simplified, resulting in cost saving at the operational level. Overall capital costs may also be reduced, provided that the design of the foundation can be adapted to multiple devices with minimum modifications. Finally, the WindWaveFloat confers the ability to increase energy production from individual floating support structures, potentially leading to a reduction in levelized energy costs, an increase in the overall capacity factor, and greater stability of the electrical power delivered to the grid. The research conducted under this grant investigated the integration of several wave energy device types into the WindFloat platform. Several of the resulting system designs demonstrated technical feasibility, but the size and design constraints of the wave energy converters (technical and economic) make the WindWaveFloat concept economically unfeasible at this time. Not enough additional generation could be produced to make the additional expense associated with wave energy conversion integration into the WindFloat worthwhile.

  2. Radio frequency wave experiments on the MST reversed field pinch

    SciTech Connect (OSTI)

    Forest, C.B.; Chattopadhyay, P.K.; Nornberg, M.D.; Prager, S.C.; Thomas, M.A. [Univ. of Wisconsin, Madison, WI (United States). Physics Dept.; Uchimoto, E. [Univ. of Montana, Missoula, MT (United States). Dept. of Physics and Astronomy; Smirnov, A.P. [Moscow State Univ. (Russian Federation); Harvey, R.W. [CompX, Del Mar, CA (United States); Ram, A.K. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Plasma Fusion Center

    1999-04-01T23:59:59.000Z

    Experiments, simulations, and theory all indicate that the magnetic fluctuations responsible for the poor confinement in the reversed field pinch (RFP) can be controlled by altering the radial profile of the current density. The magnetic fluctuations in the RFP are due to resistive MHD instabilities caused by current profile peaking; thus confinement in the RFP is ultimately the result of a misalignment between inductively driven current profiles and the stable current profiles characteristic of the Taylor state. If a technique such as rf current drive can be developed to non-inductively sustain a Taylor state (a current profile linearly stable to all tearing modes), the confinement of the RFP and its potential as a reactor concept are likely to increase. Whether there is a self-consistent path from poor confinement to greatly improved confinement through current profile modification is an issue for future experiments to address if and only if near term experiments can demonstrate: (1) coupling to and the propagation of rf waves in RFP plasmas, (2) efficient current drive, and (3) control of the power deposition which will make it possible to control the current profile. In this paper, modeling results and experimental plans are presented for two rf experiments which have the potential of satisfying these three goals: high-n{sub {parallel}} lower hybrid (LH) waves and electron Bernstein waves (EBWs).

  3. 2D modeling of electromagnetic waves in cold plasmas

    SciTech Connect (OSTI)

    Crombé, K. [Laboratory for Plasma Physics, Association EURATOM - Belgian State Trilateral Euregio Cluster, Renaissancelaan 30 Avenue de la Renaissance, B-1000 Brussels, Belgium and Department of Applied Physics, Ghent University, Sint-Pietersnieuwstraat 41 B4, B (Belgium); Van Eester, D.; Koch, R.; Kyrytsya, V. [Laboratory for Plasma Physics, Association EURATOM - Belgian State Trilateral Euregio Cluster, Renaissancelaan 30 Avenue de la Renaissance, B-1000 Brussels (Belgium)

    2014-02-12T23:59:59.000Z

    The consequences of sheath (rectified) electric fields, resulting from the different mobility of electrons and ions as a response to radio frequency (RF) fields, are a concern for RF antenna design as it can cause damage to antenna parts, limiters and other in-vessel components. As a first step to a more complete description, the usual cold plasma dielectric description has been adopted, and the density profile was assumed to be known as input. Ultimately, the relevant equations describing the wave-particle interaction both on the fast and slow timescale will need to be tackled but prior to doing so was felt as a necessity to get a feeling of the wave dynamics involved. Maxwell's equations are solved for a cold plasma in a 2D antenna box with strongly varying density profiles crossing also lower hybrid and ion-ion hybrid resonance layers. Numerical modelling quickly becomes demanding on computer power, since a fine grid spacing is required to capture the small wavelengths effects of strongly evanescent modes.

  4. Fast wave current drive: Experimental status and reactor prospects

    SciTech Connect (OSTI)

    Ehst, D.A.

    1988-03-01T23:59:59.000Z

    The fast wave is one of the two possible wave polarizations which propagate according to the basic theory of cold plasmas. It is distinguished from the other (slow wave) branch by having an electric field vector which is mainly orthogonal to the confining magnetic field of the plasma. The plasma and fast wave qualitatively assume different behavior depending on the frequency range of the launched wave. The high frequency fast wave (HFFW), with a frequency (..omega..2..pi.. )approximately) GHz) much higher than the ion cyclotron frequency (..cap omega../sub i/), suffers electron Landau damping and drives current by supplying parallel momentum to superthermal electrons in a fashion similar to lower hybrid (slow wave) current drive. In the simple theory the HFFW should be superior to the slow wave and can propagate to very high density and temperature without impediment. Experiments, however, have not conclusively shown that HFFW current drive can be achieved at densities above the slow wave current drive limit, possibly due to conversion of the launched fast waves into slow waves by density fluctuations. Alternatively, the low frequency fast wave (LFFW), with frequencies ()approxreverse arrowlt) 100 MHz) only a few times the ion cyclotron frequency, is damped by electron Landau damping and, in a hot plasma ()approxreverse arrowgt) 10 keV), by electron transit time magnetic pumping; current drive is achieved by pushing superthermal electrons, and efficiency is prediocted to be slightly better than for lower hybrid current drive. Most significantly, the slow wave does not propagate in high density plasma when ..omega.. )approximately) ..cap omega../sub i/, so parasitic coupling to the slow wave can be avoided, and no density and temperture limitations are foreseen. Experiments with fast wve current drive invariably find current drive efficiency as good as obtained in lower hybrid experiments at comparable, low temperatures. 45 refs., 4 figs., 1 tab

  5. Three-dimensional particle-in-cell simulation of electron acceleration by Langmuir waves in an inhomogeneous plasma

    SciTech Connect (OSTI)

    Pechhacker, R.; Tsiklauri, D. [School of Physics and Astronomy, Queen Mary University of London, London E1 4NS (United Kingdom)] [School of Physics and Astronomy, Queen Mary University of London, London E1 4NS (United Kingdom)

    2014-01-15T23:59:59.000Z

    A possible solution to the unexplained high intensity hard x-ray emission observable during solar flares was investigated via 3D fully relativistic, electromagnetic particle-in-cell simulations with realistic ion to electron mass ratio. A beam of accelerated electrons was injected into a magnetised, Maxwellian, homogeneous, and inhomogeneous background plasma. The electron distribution function was unstable to the beam-plasma instability and was shown to generate Langmuir waves, while relaxing to plateau formation. In order to estimate the role of the background density gradient on an unbound (infinite spatial extent) beam, three different scenarios were investigated: (a) a uniform density background; (b) a weak density gradient, n{sub e,R}/n{sub e,L}?=?3; (c) a strong gradient case, n{sub e,R}/n{sub e,L}?=?10, where n{sub e,R} and n{sub e,L} denote background electron densities on the left and right edges of the simulation box, respectively. The strong gradient case produced the largest fraction of electrons beyond 15v{sub th}. Furthermore, two cases (uniform and strong gradient background) with spatially localized beam injections were performed aiming to show drifts of the generated Langmuir wave wavenumbers, as suggested in previous studies. For the strong gradient case, the Langmuir wave power is shown to drift to smaller wavenumbers, as found in previous quasi-linear simulations.

  6. On Plane and Spherical Waves in Horns with Nonuniform Flare I. Theory of Radiation, Resonance Frequencies,

    E-Print Network [OSTI]

    Allen, Jont

    ), Stockholm 70, Sweden Summary The relation between axially symmetric plane waves in a cylindrical duct-wave is of all-pass nature, but there are high-pass cut-off frequencies for p-waves etc. A modified "Webster of higher order, assuming the wave fronts to be curved with area 8(z) while gas density and bulk modulus

  7. Whistler mode waves and the electron heat flux in the solar wind: Cluster observations

    E-Print Network [OSTI]

    Lacombe, Catherine; Matteini, Lorenzo; Santolik, Ondrej; Cornilleau-Wehrlin, Nicole; Mangeney, Andre; de Conchy, Yvonne; Maksimovic, Milan

    2014-01-01T23:59:59.000Z

    The nature of the magnetic field fluctuations in the solar wind between the ion and electron scales is still under debate. Using the Cluster/STAFF instrument, we make a survey of the power spectral density and of the polarization of these fluctuations at frequencies $f\\in[1,400]$ Hz, during five years (2001-2005), when Cluster was in the free solar wind. In $\\sim 10\\%$ of the selected data, we observe narrow-band, right-handed, circularly polarized fluctuations, with wave vectors quasi-parallel to the mean magnetic field, superimposed on the spectrum of the permanent background turbulence. We interpret these coherent fluctuations as whistler mode waves. The life time of these waves varies between a few seconds and several hours. Here we present, for the first time, an analysis of long-lived whistler waves, i.e. lasting more than five minutes. We find several necessary (but not sufficient) conditions for the observation of whistler waves, mainly a low level of the background turbulence, a slow wind, a relative...

  8. Excitation of non-radial stellar oscillations by gravitational waves: a first model

    E-Print Network [OSTI]

    D. M. Siegel; M. Roth

    2010-10-17T23:59:59.000Z

    The excitation of solar and solar-like g modes in non-relativistic stars by arbitrary external gravitational wave fields is studied starting from the full field equations of general relativity. We develop a formalism that yields the mean-square amplitudes and surface velocities of global normal modes excited in such a way. The isotropic elastic sphere model of a star is adopted to demonstrate this formalism and for calculative simplicity. It is shown that gravitational waves solely couple to quadrupolar spheroidal eigenmodes and that normal modes are only sensitive to the spherical component of the gravitational waves having the same azimuthal order. The mean-square amplitudes in case of stationary external gravitational waves are given by a simple expression, a product of a factor depending on the resonant properties of the star and the power spectral density of the gravitational waves' spherical accelerations. Both mean-square amplitudes and surface velocities show a characteristic R^8-dependence (effective R^2-dependence) on the radius of the star. This finding increases the relevance of this excitation mechanism in case of stars larger than the Sun.

  9. Effect of Impurities Scattering Potential on NMR relaxation rate in impure d-wave superconductors

    E-Print Network [OSTI]

    P. Udomsamuthirun; K. Meemon

    2009-07-20T23:59:59.000Z

    The purpose of our research is to study the nuclear spin lattice relaxation rate of impure d-wave superconductors. We use the Green function method to derive the approximation equation of density of states including the impurity scattering potential. We can get the analytic equation of the nuclear spin lattice relaxation rate that contained the impurity scattering potential in case of weak scattering potential and strong scattering potential in the simple form as the power series of order parameter and temperature . The numerical calculations show that there is coherence peak in the weak impurity scattering potential but there is no peak in the strong impurity scattering potential.

  10. Coda wave interferometry 1 Coda wave interferometry

    E-Print Network [OSTI]

    Snieder, Roel

    Coda wave interferometry 1 Coda wave interferometry An interferometer is an instrument that is sensitive to the interference of two or more waves (optical or acoustic). For example, an optical interferometer uses two interfering light beams to measure small length changes. Coda wave interferometry

  11. Refrigeration system having standing wave compressor

    DOE Patents [OSTI]

    Lucas, Timothy S. (Glen Allen, VA)

    1992-01-01T23:59:59.000Z

    A compression-evaporation refrigeration system, wherein gaseous compression of the refrigerant is provided by a standing wave compressor. The standing wave compressor is modified so as to provide a separate subcooling system for the refrigerant, so that efficiency losses due to flashing are reduced. Subcooling occurs when heat exchange is provided between the refrigerant and a heat pumping surface, which is exposed to the standing acoustic wave within the standing wave compressor. A variable capacity and variable discharge pressure for the standing wave compressor is provided. A control circuit simultaneously varies the capacity and discharge pressure in response to changing operating conditions, thereby maintaining the minimum discharge pressure needed for condensation to occur at any time. Thus, the power consumption of the standing wave compressor is reduced and system efficiency is improved.

  12. Wave Power Plant Inc | Open Energy Information

    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 onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand Jump to:Ezfeedflag JumpID-fTri GlobalJump to: navigation,Goff, 2002) | OpenEnergy AS Jump

  13. Kinetic Wave Power | Open Energy Information

    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 onYou are now leaving Energy.gov You are now leaving Energy.gov You are beingZealand Jump to: navigation, searchOf Kilauea Volcano, Hawaii |Island,KasVinod Privatea metamorphic

  14. Pair densities in density functional theory

    E-Print Network [OSTI]

    Chen, Huajie

    2015-01-01T23:59:59.000Z

    The exact interaction energy of a many-electron system is determined by the electron pair density, which is not well-approximated in standard Kohn-Sham density functional models. Here we study the (complicated but well-defined) exact universal map from density to pair density. We show that many common functionals, including the most basic version of the LDA (Dirac exchange with no correlation contribution), arise from particular approximations of this map. We develop an algorithm to compute the map numerically, and apply it to one-parameter families {a*rho(a*x)} of one-dimensional homogeneous and inhomogeneous single-particle densities. We observe that the pair density develops remarkable multiscale patterns which strongly depend on both the particle number and the "width" 1/a of the single-particle density. The simulation results are confirmed by rigorous asymptotic results in the limiting regimes a>>1 and a<<1. For one-dimensional homogeneous systems, we show that the whole spectrum of patterns is rep...

  15. Some characteristics on nonbreaking waves passing a submerged longshore bar

    E-Print Network [OSTI]

    Chandler, Pierce Leon

    1971-01-01T23:59:59.000Z

    Figure 3. Typical wave records Figure 4. The envelope of transformation ~Pa e 15 17 Figure 5. Nave forms produced in constant depth by a periodic wave generator - after Galvin (3) 18 Figure 6. Relative energy transformed to higher frequencies. . 22.... Power spectra run 4 (T = 1. 2 sec, Figure 13. Power spectra run 5 (T = 2. 0 sec, Figure 14. Power spectra run 6 (T = 2. 0 sec, Figure 15. Power spectra run 7 (T = 1. 2 sec, Figure 16. Power spectra run 8 (T = 1. 4 sec, Figure 17. Power spectra run 9...

  16. Innovative Wave Power Device Starts Producing Clean Power in Hawaii |

    Office of Environmental Management (EM)

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645 3,625 1,006 492 742 33 111 1,613 122Commercial602 1,39732on Armed

  17. Shock wave propagation in vibrofluidized granular materials

    E-Print Network [OSTI]

    Kai Huang; Guoqing Miao; Peng Zhang; Yi Yun; Rongjue Wei

    2005-11-29T23:59:59.000Z

    Shock wave formation and propagation in two-dimensional granular materials under vertical vibration are studied by digital high speed photography. The steepen density and temperature wave fronts form near the plate as granular layer collides with vibrating plate and propagate upward through the layer. The temperature front is always in the transition region between the upward and downward granular flows. The effects of driving parameters and particle number on the shock are also explored.

  18. Shock-activated electrochemical power supplies

    DOE Patents [OSTI]

    Benedick, W.B.; Graham, R.A.; Morosin, B.

    1988-11-08T23:59:59.000Z

    A shock-activated electrochemical power supply is provided which is initiated extremely rapidly and which has a long shelf life. Electrochemical power supplies of this invention are initiated much faster than conventional thermal batteries. Power supplies of this invention comprise an inactive electrolyte and means for generating a high-pressure shock wave such that the shock wave is propagated through the electrolytes rendering the electrolyte electrochemically active. 2 figs.

  19. Shock-activated electrochemical power supplies

    DOE Patents [OSTI]

    Benedick, W.B.; Graham, R.A.; Morosin, B.

    1987-04-20T23:59:59.000Z

    A shock-activated electrochemical power supply is provided which is initiated extremely rapidly and which has a long shelf life. Electrochemical power supplies of this invention are initiated much faster than conventional thermal batteries. Power supplies of this invention comprise an inactive electrolyte and means for generating a high-pressure shock wave such that the shock wave is propagated through the electrolyte rendering the electrolyte electrochemically active. 2 figs.

  20. Equation for liquid density

    SciTech Connect (OSTI)

    Yaws, C.L.; Yang, H.C.; Hopper, J.R.; Cawley, W.A. (Lamar Univ., Beaumont, TX (US))

    1991-01-01T23:59:59.000Z

    Saturated liquid densities for organic chemicals are given as functions of temperature using a modified Rackett equation.

  1. Plasma relaxation mechanics of pulsed high power microwave surface flashover

    SciTech Connect (OSTI)

    Beeson, S.; Dickens, J.; Neuber, A. [Center for Pulsed Power and Power Electronics, Department of Electrical and Computer Engineering and Department of Physics, Texas Tech University, Lubbock, Texas 79409 (United States)] [Center for Pulsed Power and Power Electronics, Department of Electrical and Computer Engineering and Department of Physics, Texas Tech University, Lubbock, Texas 79409 (United States)

    2013-09-15T23:59:59.000Z

    Microwave transmission and reflection characteristics of pulsed radio frequency field generated plasmas are elucidated for air, N{sub 2}, and He environments under pressure conditions ranging from 10 to 600 torr. The pulsed, low temperature plasma is generated along the atmospheric side of the dielectric boundary between the source (under vacuum) and the radiating environment with a thickness on the order of 5 mm and a cross sectional area just smaller than that of the waveguide. Utilizing custom multi-standard waveguide couplers and a continuous low power probing source, the scattering parameters were measured before, during, and after the high power microwave pulse with emphasis on the latter. From these scattering parameters, temporal electron density estimations (specifically the longitudinal integral of the density) were calculated using a 1D plane wave-excited model for analysis of the relaxation processes associated. These relaxation characteristics ultimately determine the maximum repetition rate for many pulsed electric field applications and thus are applicable to a much larger scope in the plasma community than just those related to high power microwaves. This manuscript discusses the diagnostic setup for acquiring the power measurements along with a detailed description of the kinematic and chemical behavior of the plasma as it decays down to its undisturbed state under various gas type and pressure conditions.

  2. Error Analysis in Nuclear Density Functional Theory

    E-Print Network [OSTI]

    Nicolas Schunck; Jordan D. McDonnell; Jason Sarich; Stefan M. Wild; Dave Higdon

    2014-07-11T23:59:59.000Z

    Nuclear density functional theory (DFT) is the only microscopic, global approach to the structure of atomic nuclei. It is used in numerous applications, from determining the limits of stability to gaining a deep understanding of the formation of elements in the universe or the mechanisms that power stars and reactors. The predictive power of the theory depends on the amount of physics embedded in the energy density functional as well as on efficient ways to determine a small number of free parameters and solve the DFT equations. In this article, we discuss the various sources of uncertainties and errors encountered in DFT and possible methods to quantify these uncertainties in a rigorous manner.

  3. Phases of holographic d-wave superconductor

    E-Print Network [OSTI]

    Krikun, Alexander

    2015-01-01T23:59:59.000Z

    We study different phases in the holographic model of d-wave superconductor. These are described by solutions to the classical equations of motion found in different ansatze. Apart from the known homogeneous d-wave superconducting phase we find three new solutions. Two of them represent two distinct families of the spatially modulated solutions, which realize the charge density wave phases in the dual theory. The third one is the new homogeneous phase with nonzero anapole moment. These phases are relevant to the physics of cuprate high-Tc superconductor in pseudogap region. While the d-wave phase preserves translation, parity and time reversal symmetry, the striped phases break translations spontaneously. Parity and time-reversal are preserved when combined with discrete half-periodic shift of the wave. In anapole phase translation symmetry is preserved, but parity and time reversal are spontaneously broken. All of the considered solutions brake the global $U(1)$. Thermodynamical treatment shows that in the s...

  4. Ion acoustic shock waves in degenerate plasmas

    SciTech Connect (OSTI)

    Akhtar, N. [Theoretical Plasma Physics Division, PINSTECH, Nilore, Islamabad 44000 Pakistan (Pakistan); Hussain, S. [Theoretical Plasma Physics Division, PINSTECH, Nilore, Islamabad 44000 Pakistan (Pakistan); Department of Physics and Applied Mathematics, PIEAS, Nilore, Islamabad 44000 Pakistan (Pakistan)

    2011-07-15T23:59:59.000Z

    Korteweg de Vries Burgers equation for negative ion degenerate dissipative plasma has been derived using reductive perturbation technique. The quantum hydrodynamic model is used to study the quantum ion acoustic shock waves. The effects of different parameters on quantum ion acoustic shock waves are studied. It is found that quantum parameter, electrons Fermi temperature, temperature of positive and negative ions, mass ratio of positive to negative ions, viscosity, and density ratio have significant impact on the shock wave structure in negative ion degenerate plasma.

  5. Counting energy packets in the electromagnetic wave

    E-Print Network [OSTI]

    Stefan Popescu; Bernhard Rothenstein

    2007-05-18T23:59:59.000Z

    We discuss the concept of energy packets in respect to the energy transported by electromagnetic waves and we demonstrate that this physical quantity can be used in physical problems involving relativistic effects. This refined concept provides results compatible to those obtained by simpler definition of energy density when relativistic effects apply to the free electromagnetic waves. We found this concept further compatible to quantum theory perceptions and we show how it could be used to conciliate between different physical approaches including the classical electromagnetic wave theory, the special relativity and the quantum theories.

  6. Scattering of internal gravity waves

    E-Print Network [OSTI]

    Leaman Nye, Abigail

    2011-04-19T23:59:59.000Z

    of the perturbed buoy- ancy field throughout a period of the motion. Curves represent cross-sections taken from the incident beam (cyan); a beam after reflection from a solid horizontal bound- ary (dark blue) and a beam after interaction with the sponge formation... wavenumber components and (b) plots power spectra calculated with Fourier and maximum entropy methods. k˜ is a nondimensional wavenumber representing the number of waves in an across-beam section of length Rc. . . . . . . 114 4.7 Two-dimensional power spectra...

  7. Advances in High-harmonic Fast Wave Physics in the National Spherical Torus Experiment

    SciTech Connect (OSTI)

    Taylor, G; Hosea, J C; LeBlanc, B P; Phillips, C K; Podesta, M; Valeo, E J; Wilson, J R; Ahn, J -W; Chen, G; Green, D L; Jaeger, E F; Maingi, R; Ryan, P M; Wilgen, J B; Heidbrink, W W; Liu, D; Bonoli, P T; Brecht, T; Choi, M

    2009-12-01T23:59:59.000Z

    Improved core high-harmonic fast wave (HHFW) heating at longer wavelengths and during start-up and plasma current ramp-up, has now been obtained by lowering the edge density with lithium wall conditioning, thereby moving the critical density for perpendicular fast-wave propagation away from the vessel wall. Lithium conditioning allowed significant HHFW core electron heating of deuterium neutral beam injection (NBI) fuelled H-mode plasmas to be observed for the first time. Large edge localized modes were observed immediately after the termination of rf power. Visible and infrared camera images show that fast wave interactions can deposit considerable rf energy on the outboard divertor. HHFW-generated parametric decay instabilities were observed to heat ions in the plasma edge and may be the cause for a measured drag on edge toroidal rotation during HHFW heating. A significant enhancement in neutron rate and fast-ion profile were measured in NBI-fuelled plasmas when HHFW heating was applied. __________________________________________________

  8. Quantification of the influence of directional sea state parameters over the performances of wave energy converters 

    E-Print Network [OSTI]

    Pascal, Remy Claude Rene

    2012-11-29T23:59:59.000Z

    Accurate predictions of the annual energy yield from wave energy converters are essential to the development of the wave industry. The current method based on power matrices uses only a small part of the data available ...

  9. Assessment of Projected Life-Cycle Costs for Wave, Tidal, Ocean...

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

    Assessment of Projected Life-Cycle Costs for Wave, Tidal, Ocean Current, and In-Stream Hydrokinetic Power Assessment of Projected Life-Cycle Costs for Wave, Tidal, Ocean Current,...

  10. 39th AIAA Fluid Dynamics Conference & Exhibit, 2225 June 2009, San Antonio, Texas Detection of Wave Propagation by Nonstationary

    E-Print Network [OSTI]

    Texas at Arlington, University of

    of Wave Propagation by Nonstationary Cross-Correlation and Cross-Spectral Density Phase A. Albert Ortiz of the propagation time of sharp disconti- nuities such as steps or spikes that model shock or detonation waves-correlation function Sxy One-sided frequency-time cross-spectral density TOF Time-of-flight ¯u Average wave propagation

  11. Experimental characterization and modeling of non-linear coupling of the LHCD power on Tore Supra

    SciTech Connect (OSTI)

    Preynas, M. [Max Planck Institut für Plasmaphysik, EURATOM Association, D-17491 Greifswald (Germany); Goniche, M.; Hillairet, J.; Litaudon, X.; Ekedahl, A. [CEA, IRFM, F-13108 Saint Paul lez Durance (France)

    2014-02-12T23:59:59.000Z

    To achieve steady state operation on future tokamaks, in particular on ITER, the unique capability of a LHCD system to efficiently drive off-axis non-inductive current is needed. In this context, it is of prime importance to study and master the coupling of LH wave to the core plasma at high power density (tens of MW/m{sup 2}). In some specific conditions, deleterious effects on the LHCD coupling are sometimes observed on Tore Supra. At high power the waves may modify the edge parameters that change the wave coupling properties in a non-linear manner. In this way, dedicated LHCD experiments have been performed using the LHCD system of Tore Supra, composed of two different conceptual designs of launcher: the Fully Active Multijunction (FAM) and the new Passive Active Multijunction (PAM) antennas. A nonlinear interaction between the electron density and the electric field has been characterized in a thin plasma layer in front of the two LHCD antennas. The resulting dependence of the power reflection coefficient with the LHCD power, leading occasionally to trips in the output power, is not predicted by the standard linear theory of the LH wave coupling. Therefore, it is important to investigate and understand the possible origin of such non-linear effects in order to avoid their possible deleterious consequences. The PICCOLO-2D code, which self-consistently treats the wave propagation in the antenna vicinity and its interaction with the local edge plasma density, is used to simulate Tore Supra discharges. The simulation reproduces very well the occurrence of a non-linear behavior in the coupling observed in the LHCD experiments. The important differences and trends between the FAM and the PAM antennas, especially a larger increase in RC for the FAM, are also reproduced by the PICCOLO-2D simulation. The working hypothesis of the contribution of the ponderomotive effect in the non-linear observations of LHCD coupling is therefore validated through this comprehensive modeling for the first time on the FAM and PAM antennas on Tore Supra.

  12. Neutral depletion and the helicon density limit

    SciTech Connect (OSTI)

    Magee, R. M.; Galante, M. E.; Carr, J. Jr.; Lusk, G.; McCarren, D. W.; Scime, E. E. [West Virginia University, Morgantown, West Virginia 26506 (United States)] [West Virginia University, Morgantown, West Virginia 26506 (United States)

    2013-12-15T23:59:59.000Z

    It is straightforward to create fully ionized plasmas with modest rf power in a helicon. It is difficult, however, to create plasmas with density >10{sup 20} m{sup ?3}, because neutral depletion leads to a lack of fuel. In order to address this density limit, we present fast (1 MHz), time-resolved measurements of the neutral density at and downstream from the rf antenna in krypton helicon plasmas. At the start of the discharge, the neutral density underneath the antenna is reduced to 1% of its initial value in 15 ?s. The ionization rate inferred from these data implies that the electron temperature near the antenna is much higher than the electron temperature measured downstream. Neutral density measurements made downstream from the antenna show much slower depletion, requiring 14 ms to decrease by a factor of 1/e. Furthermore, the downstream depletion appears to be due to neutral pumping rather than ionization.

  13. A planar-type surface-wave plasma source with a subwavelength diffraction grating inclusion for large-area plasma applications

    SciTech Connect (OSTI)

    Chen Zhaoquan; Liu Minghai; Tang Liang; Hu Peng; Hu Xiwei [College of Electrical and Electronic Engineering, HuaZhong University of Science and Technology, WuHan, HuBei 430074 (China)

    2009-07-01T23:59:59.000Z

    The electromagnetic wave through the subwavelength diffraction grating can be largely absorbed by surface-wave plasmas (SWPs). A SWP source is built with two slot-array antennas element. Due to the dissipation of surface waves in overdense plasmas, this source can provide remarkable discharge efficiency of 4.4 cm{sup 2}/W experimentally and 96% of incident power numerically. When the applied power as low as 200 W is supplied to the SWP source, a homogeneous plasma with the uniform area up to 14x36 cm{sup 2} and the plasma density up to 1.04x10{sup 18} m{sup -3} is generated under the quartz slab. By varying the incident power and gas pressure, the parameter of plasmas can be easily controlled without density jumping. Moreover, the characters of bi-Maxwellian electron energy distribution prove that our SWP source yield plasmas by surface heating actually. These excellent performances make the proposed source meet the requirements in large-area plasma processing and also give its advices for plasmas heating in next meter-size SWP sources.

  14. Using Radio Waves to Control Fusion Plasma Density

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

    AFDC Printable Version Share this resource Send a link to EERE: Alternative Fuels Data Center Home Page to someone by E-mail Share EERE: Alternative Fuels Data Center Home Page on Facebook Tweet about EERE: Alternative Fuels Data Center Home Page on Twitter Bookmark EERE: Alternative1 First Use of Energy for All Purposes (Fuel and Nonfuel), 2002; Level: National5Sales for4,645U.S. DOE Office of ScienceandMesa del SolStrengthening aTurbulence mayUndergraduateAboutUserHadoop

  15. Photon wave functions, wave-packet quantization of light, and coherence theory

    E-Print Network [OSTI]

    Brian J. Smith; M. G. Raymer

    2007-12-09T23:59:59.000Z

    The monochromatic Dirac and polychromatic Titulaer-Glauber quantized field theories (QFTs) of electromagnetism are derived from a photon-energy wave function in much the same way that one derives QFT for electrons, that is, by quantization of a single-particle wave function. The photon wave function and its equation of motion are established from the Einstein energy-momentum-mass relation, assuming a local energy density. This yields a theory of photon wave mechanics (PWM). The proper Lorentz-invariant single-photon scalar product is found to be non-local in coordinate space, and is shown to correspond to orthogonalization of the Titulaer-Glauber wave-packet modes. The wave functions of PWM and mode functions of QFT are shown to be equivalent, evolving via identical equations of motion, and completely describe photonic states. We generalize PWM to two or more photons, and show how to switch between the PWM and QFT viewpoints. The second-order coherence tensors of classical coherence theory and the two-photon wave functions are shown to propagate equivalently. We give examples of beam-like states, which can be used as photon wave functions in PWM, or modes in QFT. We propose a practical mode converter based on spectral filtering to convert between wave packets and their corresponding biorthogonal dual wave packets.

  16. Geometrical vs wave optics under gravitational waves

    E-Print Network [OSTI]

    Raymond Angélil; Prasenjit Saha

    2015-05-20T23:59:59.000Z

    We present some new derivations of the effect of a plane gravitational wave on a light ray. A simple interpretation of the results is that a gravitational wave causes a phase modulation of electromagnetic waves. We arrive at this picture from two contrasting directions, namely null geodesics and Maxwell's equations, or, geometric and wave optics. Under geometric optics, we express the geodesic equations in Hamiltonian form and solve perturbatively for the effect of gravitational waves. We find that the well-known time-delay formula for light generalizes trivially to massive particles. We also recover, by way of a Hamilton-Jacobi equation, the phase modulation obtained under wave optics. Turning then to wave optics - rather than solving Maxwell's equations directly for the fields, as in most previous approaches - we derive a perturbed wave equation (perturbed by the gravitational wave) for the electromagnetic four-potential. From this wave equation it follows that the four-potential and the electric and magnetic fields all experience the same phase modulation. Applying such a phase modulation to a superposition of plane waves corresponding to a Gaussian wave packet leads to time delays.

  17. Understanding ion cyclotron harmonic fast wave heating losses in the scrape off layer of tokamak plasmas

    SciTech Connect (OSTI)

    Bertelli, N [PPPL; Jaeger, E F; Hosea, J C; Phillips, C K; Berry, L; Bonoli, P T; Gerhardt, S P [PPPL; Green, D; LeBlanc, B [PPPL; Perkins, R J; Ryan, P M; Taylor, G; Valeo, E J; Wilso, J R; Wright, J C

    2014-07-01T23:59:59.000Z

    Fast waves at harmonics of the ion cyclotron frequency, which have been used successfully on National Spherical Torus Experiment (NSTX), will also play an important role in ITER and are a promising candidate for the Fusion Nuclear Science Facility (FNSF) designs based on spherical torus (ST). Experimental studies of high harmonic fast waves (HHFW) heating on the NSTX have demonstrated that substantial HHFW power loss occurs along the open field lines in the scrape-off layer (SOL), but the mechanism behind the loss is not yet understood. The full wave RF code AORSA, in which the edge plasma beyond the last closed flux surface (LCFS) is included in the solution domain, is applied to specific NSTX discharges in order to predict the effects and possible causes of this power loss. In the studies discussed here, a collisional damping parameter has been implemented in AORSA as a proxy to represent the real, and most likely nonlinear, damping processes. A prediction for the NSTX Upgrade (NSTX-U) experiment, that will begin operation next year, is also presented, indicating a favorable condition for the experiment due to a wider evanescent region in edge density.*Research supported by the U.S. DOE under Contract No. DE-AC02-09CH11466 with Princeton University.

  18. acoustic wave detector: Topics by E-print Network

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

    coupling of interferometer test-masses to fluctuations of atmospheric density due to the propagation of sound waves in a semispace occupied by an ideal fluid delimited by an...

  19. acoustic waves generated: Topics by E-print Network

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

    coupling of interferometer test-masses to fluctuations of atmospheric density due to the propagation of sound waves in a semispace occupied by an ideal fluid delimited by an...

  20. Internal wave energy radiated from a turbulent mixed layer

    SciTech Connect (OSTI)

    Munroe, James R., E-mail: jmunroe@mun.ca [Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X7 (Canada); Sutherland, Bruce R., E-mail: bsuther@ualberta.ca [Departments of Physics and Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2R3 (Canada)

    2014-09-15T23:59:59.000Z

    We examine mixed-layer deepening and the generation of internal waves in stratified fluid resulting from turbulence that develops in response to an applied surface stress. In laboratory experiments the stress is applied over the breadth of a finite-length tank by a moving roughened conveyor belt. The turbulence in the shear layer is characterized using particle image velocimetry to measure the kinetic energy density. The internal waves are measured using synthetic schlieren to determine their amplitudes, frequencies, and energy density. We also perform fully nonlinear numerical simulations restricted to two dimensions but in a horizontally periodic domain. These clearly demonstrate that internal waves are generated by transient eddies at the integral length scale of turbulence and which translate with the background shear along the base of the mixed layer. In both experiments and simulations we find that the energy density of the generated waves is 1%–3% of the turbulent kinetic energy density of the turbulent layer.

  1. Upper-hybrid wave-driven Alfvenic turbulence in magnetized dusty plasmas

    SciTech Connect (OSTI)

    Misra, A. P. [Department of Physics, Umeaa University, SE-901 87 Umeaa (Sweden); Banerjee, S. [Department of Mathematics, Politecnico di Torino, 10129 Torino (Italy)

    2011-03-15T23:59:59.000Z

    The nonlinear dynamics of coupled electrostatic upper-hybrid (UH) and Alfven waves (AWs) is revisited in a magnetized electron-ion plasma with charged dust impurities. A pair of nonlinear equations that describe the interaction of UH wave envelopes (including the relativistic electron mass increase) and the density as well as the compressional magnetic field perturbations associated with the AWs are solved numerically to show that many coherent solitary patterns can be excited and saturated due to modulational instability of unstable UH waves. The evolution of these solitary patterns is also shown to appear in the states of spatiotemporal coherence, temporal as well as spatiotemporal chaos, due to collision and fusion among the patterns in stochastic motion. Furthermore, these spatiotemporal features are demonstrated by the analysis of wavelet power spectra. It is found that a redistribution of wave energy takes place to higher harmonic modes with small wavelengths, which, in turn, results in the onset of Alfvenic turbulence in dusty magnetoplasmas. Such a scenario can occur in the vicinity of Saturn's magnetosphere as many electrostatic solitary structures have been observed there by the Cassini spacecraft.

  2. Excitation of fast waves near the mean gyrofrequency

    SciTech Connect (OSTI)

    Platt, R.C.; McWilliams, R.

    1986-11-03T23:59:59.000Z

    Fast waves with frequencies near the mean gyrofrequency (..omega..--(..omega../sub c//sub i/..omega../sub ce/)/sup 1/2/) were excited in a toroidal, magnetized plasma. Experimental measurements were made of wavelengths and phase velocities perpendicular to the toroidal magnetic field, and wave energy trajectories in the plasma, varying wave frequency, plasma density, and magnetic field values. Experimental results agree with predictions from the cold-plasma dispersion relation.

  3. Magnetohydrodynamics wave propagation in the neighbourhood of two dipoles

    E-Print Network [OSTI]

    J. A. McLaughlin; A. W. Hood

    2007-12-11T23:59:59.000Z

    This paper is the third in a series of investigations by the authors. The nature of fast magnetoacoustic and Alfv\\'en waves is investigated in a 2D $\\beta=0$ plasma in the neighbourhood of two dipoles. We use both numerical simulations (two-step Lax-Wendroff scheme) and analytical techniques (WKB approximation). It is found that the propagation of the linear fast wave is dictated by the Alfv\\'en speed profile and that close to the null, the wave is attracted to the neutral point. However, it is also found that in this magnetic configuration some of the wave can escape the refraction effect; this had not been seen in previous investigations by the authors. The wave split occurs near the regions of very high Alfv\\'en speed (found near the loci of the two dipoles). Also, for the set-up investigated it was found that 40% of the wave energy accumulates at the null. Ohmic dissipation will then extract the wave energy at this point. The Alfv\\'en wave behaves in a different manner in that part of the wave accumulates along the separatrices and part escapes. Hence, the current density will accumulate at this part of the topology and this is where wave heating will occur. The phenomenon of wave accumulation at a specific place is a feature of both wave types, as is the result that a fraction of the wave can now escape the numerical box when propagating in this magnetic configuration.

  4. Effects of a random spatial variation of the plasma density on the mode conversion in cold, unmagnetized, and stratified plasmas

    SciTech Connect (OSTI)

    Jung Yu, Dae [School of Space Research, Kyung Hee University, Yongin 446-701 (Korea, Republic of)] [School of Space Research, Kyung Hee University, Yongin 446-701 (Korea, Republic of); Kim, Kihong [Department of Energy Systems Research, Ajou University, Suwon 443-749 (Korea, Republic of)] [Department of Energy Systems Research, Ajou University, Suwon 443-749 (Korea, Republic of)

    2013-12-15T23:59:59.000Z

    We study the effects of a random spatial variation of the plasma density on the mode conversion of electromagnetic waves into electrostatic oscillations in cold, unmagnetized, and stratified plasmas. Using the invariant imbedding method, we calculate precisely the electromagnetic field distribution and the mode conversion coefficient, which is defined to be the fraction of the incident wave power converted into electrostatic oscillations, for the configuration where a numerically generated random density variation is added to the background linear density profile. We repeat similar calculations for a large number of random configurations and take an average of the results. We obtain a peculiar nonmonotonic dependence of the mode conversion coefficient on the strength of randomness. As the disorder increases from zero, the maximum value of the mode conversion coefficient decreases initially, then increases to a maximum, and finally decreases towards zero. The range of the incident angle in which mode conversion occurs increases monotonically as the disorder increases. We present numerical results suggesting that the decrease of mode conversion mainly results from the increased reflection due to the Anderson localization effect originating from disorder, whereas the increase of mode conversion of the intermediate disorder regime comes from the appearance of many resonance points and the enhanced tunneling between the resonance points and the cutoff point. We also find a very large local enhancement of the magnetic field intensity for particular random configurations. In order to obtain high mode conversion efficiency, it is desirable to restrict the randomness close to the resonance region.

  5. Generation of uniform large-area very high frequency plasmas by launching two specific standing waves simultaneously

    SciTech Connect (OSTI)

    Chen, Hsin-Liang, E-mail: hlchen@iner.gov.tw; Tu, Yen-Cheng; Hsieh, Cheng-Chang; Lin, Deng-Lain [Physics Division, Institute of Nuclear Energy Research (INER), Longtan, Taoyuan County 32546, Taiwan (China); Leou, Keh-Chyang [Department of Engineering and System Science, National Tsing Hua University, 101, Section 2, Kuang-Fu Road, Hsinchu 30013, Taiwan (China)

    2014-09-14T23:59:59.000Z

    With the characteristics of higher electron density and lower ion bombardment energy, large-area VHF (very high frequency) plasma enhanced chemical vapor deposition has become an essential manufacturing equipment to improve the production throughput and efficiency of thin film silicon solar cell. However, the combination of high frequency and large electrodes leads to the so-called standing wave effect causing a serious problem for the deposition uniformity of silicon thin film. In order to address this issue, a technique based on the idea of simultaneously launching two standing waves that possess similar amplitudes and are out of phase by 90° in time and space is proposed in this study. A linear plasma reactor with discharge length of 54 cm is tested with two different frequencies including 60 and 80 MHz. The experimental results show that the proposed technique could effectively improve the non-uniformity of VHF plasmas from >±60% when only one standing wave is applied to <±10% once two specific standing waves are launched at the same time. Moreover, in terms of the reactor configuration adopted in this study, in which the standing wave effect along the much shorter dimension can be ignored, the proposed technique is applicable to different frequencies without the need to alter the number and arrangement of power feeding points.

  6. Relic gravitational waves and the generalized second law

    E-Print Network [OSTI]

    German Izquierdo; Diego Pavon

    2005-01-12T23:59:59.000Z

    The generalized second law of gravitational thermodynamics is applied to the present era of accelerated expansion of the Universe. In spite of the fact that the entropy of matter and relic gravitational waves inside the event horizon diminish, the mentioned law is fulfilled provided that the expression for the entropy density of the gravitational waves satisfies a certain condition.

  7. Linear mode conversion of Langmuir/z-mode waves to radiation: Scalings of conversion efficiencies and propagation angles with temperature and magnetic field orientation

    SciTech Connect (OSTI)

    Schleyer, F.; Cairns, Iver H. [School of Physics, University of Sydney, NSW 2006 (Australia); Kim, E.-H. [Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08543 (United States)

    2013-03-15T23:59:59.000Z

    Linear mode conversion (LMC) is the linear transfer of energy from one wave mode to another in an inhomogeneous plasma. It is relevant to laboratory plasmas and multiple solar system radio emissions, such as continuum radiation from planetary magnetospheres and type II and III radio bursts from the solar corona and solar wind. This paper simulates LMC of waves defined by warm, magnetized fluid theory, specifically the conversion of Langmuir/z-mode waves to electromagnetic (EM) radiation. The primary focus is the calculation of the energy and power conversion efficiencies for LMC as functions of the angle of incidence {theta} of the Langmuir/z-mode wave, temperature {beta}=T{sub e}/m{sub e}c{sup 2}, adiabatic index {gamma}, and orientation angle {phi} between the ambient density gradient {nabla}N{sub 0} and ambient magnetic field B{sub 0} in a warm, unmagnetized plasma. The ratio of these efficiencies is found to agree well as a function of {theta}, {gamma}, and {beta} with an analytical relation that depends on the group speeds of the Langmuir/z and EM wave modes. The results demonstrate that the energy conversion efficiency {epsilon} is strongly dependent on {gamma}{beta}, {phi} and {theta}, with {epsilon}{proportional_to}({gamma}{beta}){sup 1/2} and {theta}{proportional_to}({gamma}{beta}){sup 1/2}. The power conversion efficiency {epsilon}{sub p}, on the other hand, is independent of {gamma}{beta} but does vary significantly with {theta} and {phi}. The efficiencies are shown to be maximum for approximately perpendicular density gradients ({phi} Almost-Equal-To 90 Degree-Sign ) and minimal for parallel orientation ({phi}=0 Degree-Sign ) and both the energy and power conversion efficiencies peak at the same {theta}.

  8. Deflection microwave and millimeter-wave amplifiers

    SciTech Connect (OSTI)

    Tang., C.M. [Naval Research Lab., Washington, DC (United States)] [Naval Research Lab., Washington, DC (United States); Lau, Y.Y. [Univ. of Michigan, Ann Arbor, MI (United States)] [Univ. of Michigan, Ann Arbor, MI (United States); Swyden, T.A. [FM Technologies, Inc., Fairfax, VA (United States)] [FM Technologies, Inc., Fairfax, VA (United States)

    1994-03-01T23:59:59.000Z

    A new class of microwave and millimeter-wave amplifiers, called deflectron amplifiers, which are based on the deflection of low voltage electron beams in a microstructure were analyzed. This concept may be applied in two ways: as microelectronic amplifiers or as bunched beam cathodes to power conventional amplifier configurations such as klystrodes and traveling wave tubes. Estimates for gain and efficiency are obtained from a circuit analysis. Particle codes are used to test the viability of the concept. Frequencies of operation are projected up to a few tens of GHz for microelectronic amplifiers and up to {approx}80 GHz for power amplifiers 29 refs., 5 figs.

  9. Density-dependent covariant energy density functionals

    SciTech Connect (OSTI)

    Lalazissis, G. A. [Physics Department, Aristotle University of Thessaloniki, GR-54124 (Greece)

    2012-10-20T23:59:59.000Z

    Relativistic nuclear energy density functionals are applied to the description of a variety of nuclear structure phenomena at and away fromstability line. Isoscalar monopole, isovector dipole and isoscalar quadrupole giant resonances are calculated using fully self-consistent relativistic quasiparticle randomphase approximation, based on the relativistic Hartree-Bogoliubovmodel. The impact of pairing correlations on the fission barriers in heavy and superheavy nuclei is examined. The role of pion in constructing desnity functionals is also investigated.

  10. Tokamak power system studies at ANL

    SciTech Connect (OSTI)

    Baker, C.C.; Ehst, D.A.; Brooks, J.N.; Evans, K. Jr.

    1986-06-01T23:59:59.000Z

    The following features, in particular, have been examined: (a) large aspect ratio (A approx. = 6), which may ease maintenance; (b) high beta (..beta.. greater than or equal to 0.20) without indentation, which brings the maximum toroidal field down to about 6 to 7 T; (c) low toroidal current (I approx. = 4MA), which reduces the cost of the current drive and equilibrium field system; and (d) steady state operation with current density control via fast and slow wave current drive. The key to high beta operation with low toroidal current lies in utilizing second stability regime equilibria with the required current distributions produced by an appropriate selection of wave driver frequencies and power spectra. The ray tracing and current drive calculation is self-consistent with the actual magnetic fields they produce in the plasma. The impurity control activities in TPSS have emphasized the self-pumping concept as applied to using the entire first wall or ''slot'' limiters. The blanket design effort has emphasized liquid metal and Flibe concepts. The reference concept is a liquid lithium/vanadium, self-cooled configuration. Overall, there exists a number of major design improvements which will substantially improve the attractiveness of tokamak reactors.

  11. Water Waves Roger Grimshaw

    E-Print Network [OSTI]

    ,2) provide a kinematic description of water waves, which to this point means that the conditionsWater Waves Roger Grimshaw May 7, 2003 Abstract A short review of the theory of weakly nonlinear water waves, prepared for the forthcoming Encyclopedia of Nonlinear Science 1 Introduction Water waves

  12. Can New Nuclear Power Plants be Project Financed?

    E-Print Network [OSTI]

    Taylor, Simon

    This paper considers the prospects for financing a wave of new nuclear power plants (NPP) using project financing, which is used widely in large capital intensive infrastructure investments, including the power and gas sectors, but has...

  13. Propagation of electromagnetic waves in a structured ionosphere

    SciTech Connect (OSTI)

    Murphy, T.

    1996-06-01T23:59:59.000Z

    The ionosphere is a birefringent medium which strongly affects the transmission of very high frequency (vhf) radio signals. These effects must be understood in detail if one wishes to look at the propagation of wide bandwidth coherent signals through the ionosphere. We develop a general perturbative solution of Maxwell`s equations for vhf signals propagating in the ionosphere, subject only to mild restrictions on the ionospheric structure. This solution can be extended to give the propagating field to any desired degree of precision. The case of a laminar ionosphere with harmonic waves is developed in greater detail, and we show how to calculate the ray path in this case. This solution is used to elucidate the effects of refraction on the phase of the signal, and we calculate the spatial- and frequency-coherence functions. The electric field for a laminar ionosphere without waves is analyzed to clarify the physical origins of the terms modifying the signal phase. We then calculate the solution in this case for the Appleton-Hartree model of the ionospheric dielectric function and express the result as a series in inverse powers of frequency. We conclude by calculating the ray path for a model ionosphere using the Appleton-Hartree dielectric function and a parabolic layer for the electron density.

  14. Multiscale modeling of oscillations and spiral waves in Dictyostelium populations

    E-Print Network [OSTI]

    Javad Noorbakhsh; David Schwab; Allyson Sgro; Thomas Gregor; Pankaj Mehta

    2014-09-12T23:59:59.000Z

    Unicellular organisms exhibit elaborate collective behaviors in response to environmental cues. These behaviors are controlled by complex biochemical networks within individual cells and coordinated through cell-to-cell communication. Describing these behaviors requires new mathematical models that can bridge scales -- from biochemical networks within individual cells to spatially structured cellular populations. Here, we present a family of multiscale models for the emergence of spiral waves in the social amoeba Dictyostelium discoideum. Our models exploit new experimental advances that allow for the direct measurement and manipulation of the small signaling molecule cAMP used by Dictyostelium cells to coordinate behavior in cellular populations. Inspired by recent experiments, we model the Dictyostelium signaling network as an excitable system coupled to various pre-processing modules. We use this family of models to study spatially unstructured populations by constructing phase diagrams that relate the properties of population-level oscillations to parameters in the underlying biochemical network. We then extend our models to include spatial structure and show how they naturally give rise to spiral waves. Our models exhibit a wide range of novel phenomena including a density dependent frequency change, bistability, and dynamic death due to slow cAMP dynamics. Our modeling approach provides a powerful tool for bridging scales in modeling of Dictyostelium populations.

  15. Power Spectra in V-band and Halpha of Nine Irregular Galaxies

    E-Print Network [OSTI]

    Kyle W. Willett; Bruce G. Elmegreen; Deidre A. Hunter

    2005-03-14T23:59:59.000Z

    Fourier transform power spectra of major axis cuts in V and Halpha images were made for a sample of 9 irregular galaxies. These power spectra reveal structure over a wide range of scales. For 6 of the galaxies the power spectrum slopes at intermediate scales (1-400 pc) in the V-band images range from -1.3 to -1.5. The similarity of slopes suggests that the same processes are structuring these systems. These slopes are slightly shallower than what is observed in other galaxies in HI, molecular emission, dust extinction, and optical light. Three of the galaxies have flat power spectra like noise from the sky; these three galaxies are relatively indistinct in the direct images. The power spectrum slope for Halpha steepens with increasing star formation rate, ranging from a shallow value comparable to the noise at low rates to a steep value with a slope of -1.5 at high rates. This change reflects the increasing areal filling factor of Halpha emission with increasing star formation rate, and an apparently universal slope inside the Halpha regions that is comparable to that for Kolmogorov turbulence. The power spectrum of HI in one galaxy has a steeper power law, with a slope of -2.9. The fact that the power laws of star formation are about the same for dwarf galaxies and giant spiral galaxies suggests the microscopic processes are the same, independent of spiral density waves and galaxy size.

  16. MHK Projects/US Navy Wave Energy Technology WET Program at Marine...

    Open Energy Info (EERE)

    assessment was completed with an objective of demonstrating the applicability of wave power for use at US Navy bases worldwide. Project Installed Capacity (MW) 1 Device Nameplate...

  17. Electron scattering and nonlinear trapping by oblique whistler waves: The critical wave intensity for nonlinear effects

    SciTech Connect (OSTI)

    Artemyev, A. V., E-mail: ante0226@gmail.com; Vasiliev, A. A. [Space Research Institute, RAS, Moscow (Russian Federation); Mourenas, D.; Krasnoselskikh, V. V. [LPC2E/CNRS—University of Orleans, Orleans (France); Agapitov, O. V. [Space Sciences Laboratory, University of California, Berkeley, California 94720 (United States)

    2014-10-15T23:59:59.000Z

    In this paper, we consider high-energy electron scattering and nonlinear trapping by oblique whistler waves via the Landau resonance. We use recent spacecraft observations in the radiation belts to construct the whistler wave model. The main purpose of the paper is to provide an estimate of the critical wave amplitude for which the nonlinear wave-particle resonant interaction becomes more important than particle scattering. To this aim, we derive an analytical expression describing the particle scattering by large amplitude whistler waves and compare the corresponding effect with the nonlinear particle acceleration due to trapping. The latter is much more rare but the corresponding change of energy is substantially larger than energy jumps due to scattering. We show that for reasonable wave amplitudes ?10–100?mV/m of strong whistlers, the nonlinear effects are more important than the linear and nonlinear scattering for electrons with energies ?10–50?keV. We test the dependencies of the critical wave amplitude on system parameters (background plasma density, wave frequency, etc.). We discuss the role of obtained results for the theoretical description of the nonlinear wave amplification in radiation belts.

  18. On the wave energy potential of Western Black Sea shelf

    E-Print Network [OSTI]

    Galabov, Vasko

    2013-01-01T23:59:59.000Z

    In the present study we evaluate the approaches to estimate the wave energy potential of the western Black Sea shelf with numerical models. For the purpose of our evaluation and due to the lack of long time series of measurements in the selected area of the Black Sea, we compare the modeled mean wave power flux output from the SWAN wave model with the only available long term measurements from the buoy of Gelendzhik for the period 1997-2003 (with gaps). The forcing meteorological data for the numerical wave models for the selected years is extracted from the ERA Interim reanalysis of ECMWF (European Centre for Medium range Forecasts). For the year 2003 we also compare the estimated wave power with the modeled by SWAN, using ALADIN regional atmospheric model winds. We try to identify the shortcomings and limitations of the numerical modeling approach to the evaluation of the wave energy potential in Black Sea.

  19. PowerPoint Presentation

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

    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 DataDepartment of Energy Your Density Isn'tOrigin of Contamination in235-1Department of60Power Purchase Agreements PowerPowerCentsDC

  20. Evaluation of weld porosity in laser beam seam welds: optimizing continuous wave and square wave modulated processes.

    SciTech Connect (OSTI)

    Ellison, Chad M. (Honeywell FM& T, Kansas City, MO); Perricone, Matthew; Faraone, Kevin M. (Honeywell FM& T, Kansas City, MO); Roach, Robert Allen; Norris, Jerome T.

    2007-02-01T23:59:59.000Z

    Nd:YAG laser joining is a high energy density (HED) process that can produce high-speed, low-heat input welds with a high depth-to-width aspect ratio. This is optimized by formation of a ''keyhole'' in the weld pool resulting from high vapor pressures associated with laser interaction with the metallic substrate. It is generally accepted that pores form in HED welds due to the instability and frequent collapse of the keyhole. In order to maintain an open keyhole, weld pool forces must be balanced such that vapor pressure and weld pool inertia forces are in equilibrium. Travel speed and laser beam power largely control the way these forces are balanced, as well as welding mode (Continuous Wave or Square Wave) and shielding gas type. A study into the phenomenon of weld pool porosity in 304L stainless steel was conducted to better understand and predict how welding parameters impact the weld pool dynamics that lead to pore formation. This work is intended to aid in development and verification of a finite element computer model of weld pool fluid flow dynamics being developed in parallel efforts and assist in weld development activities for the W76 and future RRW programs.

  1. the wave model A traveling wave is an organized disturbance

    E-Print Network [OSTI]

    Winokur, Michael

    1 waves the wave model A traveling wave is an organized disturbance propagating at a well-defined wave speed v. · In transverse waves the particles of the medium move perpendicular to the direction of wave propagation. · In longitudinal waves the particles of the medium move parallel to the direction

  2. Stable operating regime for traveling wave devices

    DOE Patents [OSTI]

    Carlsten, Bruce E. (Los Alamos, NM)

    2000-01-01T23:59:59.000Z

    Autophase stability is provided for a traveling wave device (TWD) electron beam for amplifying an RF electromagnetic wave in walls defining a waveguide for said electromagnetic wave. An off-axis electron beam is generated at a selected energy and has an energy noise inherently arising from electron gun. The off-axis electron beam is introduced into the waveguide. The off-axis electron beam is introduced into the waveguide at a second radius. The waveguide structure is designed to obtain a selected detuning of the electron beam. The off-axis electron beam has a velocity and the second radius to place the electron beam at a selected distance from the walls defining the waveguide, wherein changes in a density of the electron beam due to the RF electromagnetic wave are independent of the energy of the electron beam to provide a concomitant stable operating regime relative to the energy noise.

  3. Fast waves and electron current drive in the Irvine Torus

    SciTech Connect (OSTI)

    Platt, R.C.

    1987-01-01T23:59:59.000Z

    This work reports the results of experimental studies of the fast wave with frequencies near the mean gyro-frequency in magnetized, toroidal plasmas with comparison to theory. Experiment investigating fast-wave dispersion and damping, and the use of unidirectional fast waves to drive steady-state electron currents were performed on the Irvine Torus. The wave was excited in the plasmas by a phased array antenna which allowed launching of uni- or bi-directional fast waves around the torus. Probe measurements of the angle of propagation of wave energy, radial wavelengths, and the direction and magnitude of radial wave phase velocities were found to be in good agreement with predictions from cold plasma theory. Measurements of fast-wave damping showed the observed damping lengths to be anomalously short when compared to predictions for electron Landau damping, transit-time magnetic pumping, and collisional damping, but may be explained by effects due to fast-wave scattering from drift-wave density fluctuations. Steady-state electron currents were driven by unidirectional fast waves. Up to 14% of the wave energy was converted to poloidal magnetic field energy. The maximum current observed was found to be in rough agreement with a prediction from quasi-linear theory.

  4. Cyclotron waves in a non-neutral plasma column

    SciTech Connect (OSTI)

    Dubin, Daniel H. E. [Department of Physics, University of California at San Diego, La Jolla, California 92093 (United States)

    2013-04-15T23:59:59.000Z

    A kinetic theory of linear electrostatic plasma waves with frequencies near the cyclotron frequency {Omega}{sub c{sub s}} of a given plasma species s is developed for a multispecies non-neutral plasma column with general radial density and electric field profiles. Terms in the perturbed distribution function up to O(1/{Omega}{sub c{sub s}{sup 2}}) are kept, as are the effects of finite cyclotron radius r{sub c} up to O(r{sub c}{sup 2}). At this order, the equilibrium distribution is not Maxwellian if the plasma temperature or rotation frequency is not uniform. For r{sub c}{yields}0, the theory reproduces cold-fluid theory and predicts surface cyclotron waves propagating azimuthally. For finite r{sub c}, the wave equation predicts that the surface wave couples to radially and azimuthally propagating Bernstein waves, at locations where the wave frequency equals the local upper hybrid frequency. The equation also predicts a second set of Bernstein waves that do not couple to the surface wave, and therefore have no effect on the external potential. The wave equation is solved both numerically and analytically in the WKB approximation, and analytic dispersion relations for the waves are obtained. The theory predicts that both types of Bernstein wave are damped at resonances, which are locations where the Doppler-shifted wave frequency matches the local cyclotron frequency as seen in the rotating frame.

  5. Power conditioning system for energy sources

    DOE Patents [OSTI]

    Mazumder, Sudip K. (Chicago, IL); Burra, Rajni K. (Chicago, IL); Acharya, Kaustuva (Chicago, IL)

    2008-05-13T23:59:59.000Z

    Apparatus for conditioning power generated by an energy source includes an inverter for converting a DC input voltage from the energy source to a square wave AC output voltage, and a converter for converting the AC output voltage from the inverter to a sine wave AC output voltage.

  6. Nonlinear, stationary electrostatic ion cyclotron waves: Exact solutions for solitons, periodic waves, and wedge shaped waveforms

    SciTech Connect (OSTI)

    McKenzie, J. F. [Department of Mathematics, Statistics and Physics, Durban University of Technology, Steve Biko Campus, Durban 4001 (South Africa); School of Mathematical Sciences, University of KwaZulu-Natal, Private Bag: X54001, Durban 4001 (South Africa); Doyle, T. B. [Materials Research Division, iThemba LABS, P.O.Box 722, Somerset West, 7129, South Africa and School of Chemistry and Physics, University of KwaZulu-Natal, Private Bag: X54001, Durban 4001 (South Africa); Rajah, S. S. [Department of Mathematics, Statistics and Physics, Durban University of Technology, Steve Biko Campus, Durban 4001 (South Africa)

    2012-11-15T23:59:59.000Z

    The theory of fully nonlinear stationary electrostatic ion cyclotron waves is further developed. The existence of two fundamental constants of motion; namely, momentum flux density parallel to the background magnetic field and energy density, facilitates the reduction of the wave structure equation to a first order differential equation. For subsonic waves propagating sufficiently obliquely to the magnetic field, soliton solutions can be constructed. Importantly, analytic expressions for the amplitude of the soliton show that it increases with decreasing wave Mach number and with increasing obliquity to the magnetic field. In the subsonic, quasi-parallel case, periodic waves exist whose compressive and rarefactive amplitudes are asymmetric about the 'initial' point. A critical 'driver' field exists that gives rise to a soliton-like structure which corresponds to infinite wavelength. If the wave speed is supersonic, periodic waves may also be constructed. The aforementioned asymmetry in the waveform arises from the flow being driven towards the local sonic point in the compressive phase and away from it in the rarefactive phase. As the initial driver field approaches the critical value, the end point of the compressive phase becomes sonic and the waveform develops a wedge shape. This feature and the amplitudes of the compressive and rarefactive portions of the periodic waves are illustrated through new analytic expressions that follow from the equilibrium points of a wave structure equation which includes a driver field. These expressions are illustrated with figures that illuminate the nature of the solitons. The presently described wedge-shaped waveforms also occur in water waves, for similar 'transonic' reasons, when a Coriolis force is included.

  7. Physica D 191 (2004) 121136 Wave equation for sound in fluids with vorticity

    E-Print Network [OSTI]

    Visser, Matt

    Physica D 191 (2004) 121­136 Wave equation for sound in fluids with vorticity Santiago Esteban illustrate our formalism by applying it to waves propagating in a uniformly rotating fluid where the sound and on the local fluid density and speed of sound. The curved space-time interpretation of the wave equation

  8. Non-Reflecting Internal Wave Beam Propagation in the Deep Ocean Roger Grimshaw1)

    E-Print Network [OSTI]

    ). Here we analyze theoretically the penetration of internal waves in an ocean with continuousNon-Reflecting Internal Wave Beam Propagation in the Deep Ocean Roger Grimshaw1) , Efim Pelinovsky1 2008 Using linear internal wave theory for an ocean stratified by both density and current, we identify

  9. 1. INTRODUCTION The investigation of whistler waves excitation and propagation in Earth

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    disturbance near antenna was about Bmax/B0~5%. #12;High frequency probe whistler waves (f0=80-200 MHz) were magnetic field disturbance the whistler wave (frequency f0=160 MHz is close to local electron cyclotron and parametric whistler wave interaction with plasma density and magnetic field variations. Amplitude-frequency

  10. Density Functional Theory with Dissipation: Transport through Single Molecules

    SciTech Connect (OSTI)

    Kieron Burke

    2012-04-30T23:59:59.000Z

    A huge amount of fundamental research was performed on this grant. Most of it focussed on fundamental issues of electronic structure calculations of transport through single molecules, using density functional theory. Achievements were: (1) First density functional theory with dissipation; (2) Pseudopotential plane wave calculations with master equation; (3) Weak bias limit; (4) Long-chain conductance; and (5) Self-interaction effects in tunneling.

  11. Simulation of anisotropic wave propagation in Vertical Seismic Profiles

    E-Print Network [OSTI]

    Durussel, Vincent Bernard

    2004-09-30T23:59:59.000Z

    they are powerful tools to simulate seismic wave propagation in three-dimensional anisotropic subsurface models. The code is currently under development using a C++ object oriented programming approach because it provides high flexibility in the design of new...

  12. Sandia National Laboratories: resonant wave-energy converter...

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

    resonant wave-energy converter devices Inter-Agency Agreement Signed between DOE's Wind and Water Power Program and Carderock On December 3, 2014, in Energy, News, News & Events,...

  13. MATHEMATICAL ANALYSIS OF A WAVE ENERGY CONVERTER ARNAUD ROUGIREL

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    for buoy-type ocean wave energy converter. The simplest model for this scheme is a non autonomous piecewise): see [OOS10]. Basically, a WEC is a floating body with a power takeoff system. It uses the vertical

  14. Self-similar solutions for the emergence of energy varying shock waves from plane-parallel atmospheres

    E-Print Network [OSTI]

    Akihiro Suzuki; Toshikazu Shigeyama

    2007-02-09T23:59:59.000Z

    We present a self-similar solution to describe the propagation of a shock wave whose energy is deposited or lost at the front. Both of the propagation of the shock wave in a medium having a power-law density profile and the expansion of the medium to a vacuum after the shock breakout are described with a Lagrangian coordinate. The Chapman-Jouguet detonation is found to accelerate the medium most effectively. The results are compared with some numerical simulations in the literature. We derive the fractions of the deposited/lost energy at the shock front in some specific cases, which will be useful when applying this solution to actual phenomena.

  15. Fast wave stabilization/destabilization of drift waves in a plasma

    SciTech Connect (OSTI)

    Kumar, Pawan; Tripathi, V. K. [Department of Physics, IIT Delhi, New Delhi-110016 (India)

    2013-03-15T23:59:59.000Z

    Four wave-nonlinear coupling of a large amplitude whistler with low frequency drift wave and whistler wave sidebands is examined. The pump and whistler sidebands exert a low frequency ponderomotive force on electrons introducing a frequency shift in the drift wave. For whistler pump propagating along the ambient magnetic field B{sub s}z-caret with wave number k(vector sign){sub 0}, drift waves of wave number k(vector sign)=k(vector sign){sub Up-Tack }+k{sub ||}z-caret see an upward frequency shift when k{sub Up-Tack }{sup 2}/k{sub 0}{sup 2}>4k{sub ||}/k{sub 0} and are stabilized once the whistler power exceeds a threshold value. The drift waves of low transverse wavelength tend to be destabilized by the nonlinear coupling. Oblique propagating whistler pump with transverse wave vector parallel to k(vector sign){sub Up-Tack} is also effective but with reduced effectiveness.

  16. Periodic subsystem density-functional theory

    SciTech Connect (OSTI)

    Genova, Alessandro; Pavanello, Michele, E-mail: m.pavanello@rutgers.edu [Department of Chemistry, Rutgers University, Newark, New Jersey 07102 (United States); Ceresoli, Davide [Department of Chemistry, Rutgers University, Newark, New Jersey 07102 (United States); CNR-ISTM, Institute of Molecular Sciences and Technologies, Milano (Italy)

    2014-11-07T23:59:59.000Z

    By partitioning the electron density into subsystem contributions, the Frozen Density Embedding (FDE) formulation of subsystem Density Functional Theory (DFT) has recently emerged as a powerful tool for reducing the computational scaling of Kohn–Sham DFT. To date, however, FDE has been employed to molecular systems only. Periodic systems, such as metals, semiconductors, and other crystalline solids have been outside the applicability of FDE, mostly because of the lack of a periodic FDE implementation. To fill this gap, in this work we aim at extending FDE to treat subsystems of molecular and periodic character. This goal is achieved by a dual approach. On one side, the development of a theoretical framework for periodic subsystem DFT. On the other, the realization of the method into a parallel computer code. We find that periodic FDE is capable of reproducing total electron densities and (to a lesser extent) also interaction energies of molecular systems weakly interacting with metallic surfaces. In the pilot calculations considered, we find that FDE fails in those cases where there is appreciable density overlap between the subsystems. Conversely, we find FDE to be in semiquantitative agreement with Kohn–Sham DFT when the inter-subsystem density overlap is low. We also conclude that to make FDE a suitable method for describing molecular adsorption at surfaces, kinetic energy density functionals that go beyond the GGA level must be employed.

  17. Photon wave function

    E-Print Network [OSTI]

    Iwo Bialynicki-Birula

    2005-08-26T23:59:59.000Z

    Photon wave function is a controversial concept. Controversies stem from the fact that photon wave functions can not have all the properties of the Schroedinger wave functions of nonrelativistic wave mechanics. Insistence on those properties that, owing to peculiarities of photon dynamics, cannot be rendered, led some physicists to the extreme opinion that the photon wave function does not exist. I reject such a fundamentalist point of view in favor of a more pragmatic approach. In my view, the photon wave function exists as long as it can be precisely defined and made useful.

  18. Oxides having high energy densities

    DOE Patents [OSTI]

    Ceder, Gerbrand; Kang, Kisuk

    2013-09-10T23:59:59.000Z

    Certain disclosed embodiments generally relate to oxide materials having relatively high energy and/or power densities. Various aspects of the embodiments are directed to oxide materials having a structure B.sub.i(M.sub.jY.sub.k)O.sub.2, for example, a structure Li.sub.j(Ni.sub.jY.sub.k)O.sub.2 such as Li(Ni.sub.0.5Mn.sub.0.5)O.sub.2. In this structure, Y represents one or more atoms, each independently selected from the group consisting of alkaline earth metals, transition metals, Group 14 elements, Group 15, or Group 16 elements. In some embodiments, such an oxide material may have an O3 crystal structure, and/or a layered structure such that the oxide comprises a plurality of first, repeating atomic planes comprising Li, and a plurality of second, repeating atomic planes comprising Ni and/or Y.

  19. Low-frequency fluid waves in fractures and pipes

    SciTech Connect (OSTI)

    Korneev, Valeri

    2010-09-01T23:59:59.000Z

    Low-frequency analytical solutions have been obtained for phase velocities of symmetrical fluid waves within both an infinite fracture and a pipe filled with a viscous fluid. Three different fluid wave regimes can exist in such objects, depending on the various combinations of parameters, such as fluid density, fluid viscosity, walls shear modulus, channel thickness, and frequency. Equations for velocities of all these regimes have explicit forms and are verified by comparisons with the exact solutions. The dominant role of fractures in rock permeability at field scales and the strong amplitude and frequency effects of Stoneley guided waves suggest the importance of including these wave effects into poroelastic theories.

  20. On Heating of Cluster Cooling Flows by Sound Waves

    E-Print Network [OSTI]

    Yutaka Fujita; Takeru Ken Suzuki

    2005-08-10T23:59:59.000Z

    We investigate heating of the cool core of a galaxy cluster through the dissipation of sound waves excited by the activities of the central active galactic nucleus (AGN). Using a weak shock theory, we show that this heating mechanism alone cannot reproduce observed temperature and density profiles of a cluster, because the dissipation length of the waves is much smaller than the size of the core and thus the wave energy is not distributed to the whole core. However, we find that if it is combined with thermal conduction from the hot outer layer of the cluster, the wave heating can reproduce the observational results.

  1. MAKING WAVES AT FAU FLORIDA ATLANTIC UNIVERSITY

    E-Print Network [OSTI]

    Fernandez, Eduardo

    to generate energy by harnessing the power of Florida's ocean currents. FAU has been named to Military TimesMAKING WAVES AT FAU FLORIDA ATLANTIC UNIVERSITY QUICK FACTS #12;About FAu 1 PeoPle 7 AcAdemics 12 Marine Renewable Energy Center, a federally funded research facility that is developing technology

  2. Rogue Wave Modes for the Long Wave-Short Wave Resonance Kwok Wing CHOW*(1)

    E-Print Network [OSTI]

    1 Rogue Wave Modes for the Long Wave-Short Wave Resonance Model Kwok Wing CHOW*(1) , Hiu Ning CHAN.45.Yv; 47.35.Fg ABSTRACT The long wave-short wave resonance model arises physically when the phase velocity of a long wave matches the group velocity of a short wave. It is a system of nonlinear evolution

  3. Double Kelvin Wave Cascade in Superfluid Helium

    E-Print Network [OSTI]

    G. Boffetta; A. Celani; D. Dezzani; J. Laurie; S. Nazarenko

    2008-10-20T23:59:59.000Z

    We study the double cascade of energy and wave action in a local model of superfluid vortex filaments. The model is obtained from a truncated expansion of the 2D Local Induction Approximation and it is shown to support six-wave interactions. We argue that, because of the uncertainty in the vortex core profile, this model has the same status of validity as the traditionally used Biot-Savart model with cutoff, but it has advantage of being much simpler. Our minimal model leads to a wave kinetic equation for which we predict existence of two distinct power-law scaling in the spectrum, corresponding to a direct cascade of energy and an inverse one of wave action. Direct numerical simulations confirm the theoretical predictions in the weak turbulence regime.

  4. THE RESPONSE OF A THREE-DIMENSIONAL SOLAR ATMOSPHERE TO WAVE-DRIVEN JETS

    SciTech Connect (OSTI)

    Scullion, E. [Institute of Theoretical Astrophysics, University of Oslo (Norway); Erdelyi, R.; Fedun, V. [Solar Physics and Space Plasma Research Centre (SP2RC), Department of Applied Mathematics, University of Sheffield, Sheffield S3 7RH (United Kingdom); Doyle, J. G., E-mail: eamonms@astro.uio.no, E-mail: robertus@sheffield.ac.uk, E-mail: v.fedun@sheffield.ac.uk, E-mail: jgd@arm.ac.uk [Armagh Observatory, College Hill, Armagh BT61 9DG (United Kingdom)

    2011-12-10T23:59:59.000Z

    Global oscillations from the solar interior are, mainly, pressure-driven (p-modes) oscillations with a peak power of a five-minute period. These oscillations are considered to manifest in many phenomena in the lower solar atmosphere, most notably, in spicules. These small-scale jets may provide the key to understanding the powering mechanisms of the transition region (TR) and lower corona. Here, we simulate the formation of wave-driven (type-I) spicule phenomena in three dimensions and the transmission of acoustic waves from the lower chromosphere and into the corona. The outer atmosphere oscillates in response to the jet formation, and in turn, we reveal the formation of a circular seismic surface wave, which we name as a Transition Region Quake (TRQ). The TRQ forms as a consequence of an upward propelling spicular wave train that repeatedly punctures and energizes the TR. The steep density gradient enables the TRQ to develop and radially fan outward from the location where the spicular plasma column impinges the TR. We suggest the TRQ formation as a formidable mechanism in continuously sustaining part of the energy budget of the TR. We present a supporting numerical model which allow us to determine the level of energy dumping at the TR by upward-propagating p-modes. Upon applying a wavelet analysis on our simulations we identify the presence of a chromospheric cavity which resonates with the jet propagation and leaves behind an oscillatory wake with a distinctive periodicity. Through our numerical analysis we also discover type-I spicule turbulence leading to a convection-based motion in the low corona.

  5. Experimental observation of the behaviour of cogenerated dusty plasma using a bipolar pulsed direct current power supply

    SciTech Connect (OSTI)

    Sarkar, Sanjib; Bose, M. [Department of Physics, Jadavpur University, Kolkata 700032 (India); Pramanik, J. [Kharagpur College, Kharagpur 721305, West Bengal (India); Mukherjee, S. [FCIPT, Institute for Plasma Research, Gandhinagar 382428 (India)

    2013-02-15T23:59:59.000Z

    We have experimentally observed the behaviour of cogenerated dusts in unmagnetized plasma produced using a bipolar pulsed dc power supply. In this experiment, the dust particles have been generated through sputtering of graphite cathode and were stratified between two electrodes. This stratification of dust clouds has obtained at a typical range of plasma parameters, namely, 650 V (peak-to-peak) with 0.2 mbar pressure. In above condition, we detected the Taylor-like instability at the interface of two dusty clouds with different densities. A very less dust density (void like) region inside the lesser dust density portion is also noted. Again, it has been observed that a self excited dust density wave propagates towards the higher density dust fluid inside the system as well as a stationary band structure of thin multiple layers of dust particles when we apply a higher voltage (750 V peak-to-peak). The wavelength, phase velocity, and frequency of the excited wave have also been estimated.

  6. Power-Aware Task Motion for Enhancing Dynamic Range

    E-Print Network [OSTI]

    Chou, Pai H.

    . They are being built today to draw energy from solar power, wind power, or even ocean waves. They represent is that many of these new energy sources are far from being ideal power supplies. For example, the output for fixed budgets. For example, a system with an XScale draws approximately 1W of power, but when the solar

  7. Coded modulation with Low Density Parity Check codes

    E-Print Network [OSTI]

    Narayanaswami, Ravi

    2001-01-01T23:59:59.000Z

    This thesis proposes the design of Low Density Parity Check (LDPC) codes for cases where coded modulation is used. We design these codes by extending the idea of Density Evolution (DE) that has been introduced as a powerful tool to analyze LDPC...

  8. New wave generation

    E-Print Network [OSTI]

    Mercier, Matthieu J.

    We present the results of a combined experimental and numerical study of the generation of internal waves using the novel internal wave generator design of Gostiaux et al. (Exp. Fluids, vol. 42, 2007, pp. 123–130). This ...

  9. Noninvasive method for determining the liquid level and density inside of a container

    DOE Patents [OSTI]

    Sinha, Dipen N. (Los Alamos, NM)

    2000-01-01T23:59:59.000Z

    Noninvasive method for determining the liquid level and density inside of a container having arbitrary dimension and shape. By generating a flexural acoustic wave in the container shell and measuring the phase difference of the detected flexural wave from that of the originally generated wave a small distance from the generated wave, while moving the generation and detection means through the liquid/vapor interface, this interface can be detected. Both the wave generation and wave detection may be achieved by transducers on the surface of the container. A change in the phase difference over the outer surface of the vessel signifies that a liquid/vapor interface has been crossed, while the magnitude of the phase difference can be related to fluid density immediately opposite the measurement position on the surface of the vessel.

  10. High density matter

    E-Print Network [OSTI]

    J. R. Stone

    2013-02-11T23:59:59.000Z

    The microscopic composition and properties of matter at super-saturation densities have been the subject of intense investigation for decades. The scarcity of experimental and observational data has lead to the necessary reliance on theoretical models. However, there remains great uncertainty in these models, which, of necessity, have to go beyond the over-simple assumption that high density matter consists only of nucleons and leptons. Heavy strange baryons, mesons and quark matter in different forms and phases have to be included to fulfil basic requirements of fundamental laws of physics. In this review the latest developments in construction of the Equation of State (EoS) of high-density matter at zero and finite temperature assuming different composition of the matter are surveyed. Critical comparison of model EoS with available observational data on neutron stars, including gravitational masses, radii and cooling patterns is presented. The effect of changing rotational frequency on the composition of neutron stars during their lifetime is demonstrated. Compatibility of EoS of high-density, low temperature compact objects and low density, high temperature matter created in heavy-ion collisions is discussed.

  11. Theoretical Examination of Transfer Cavities in a Standing-wave Free-electron Laser Two-beam Accelerator

    E-Print Network [OSTI]

    Govil, R.

    2008-01-01T23:59:59.000Z

    Standing-Wave Free-Electron Laser Two-Beam Accelerator",the Standing-Wave Free-Electron Laser Two-Beam Accelerator",A.M. Sessler, "The Free-Electron Laser as a Power Source for

  12. Wave | OpenEI Community

    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 onYou are now leaving Energy.gov You are now leaving Energy.gov You are being directedAnnualProperty Edit withTianlin BaxinUmweltVillageGraph HomeWaranaWater Power ForumGeothermalWave

  13. Density Matrix Topological Insulators

    E-Print Network [OSTI]

    A. Rivas; O. Viyuela; M. A. Martin-Delgado

    2013-10-31T23:59:59.000Z

    Thermal noise can destroy topological insulators (TI). However we demonstrate how TIs can be made stable in dissipative systems. To that aim, we introduce the notion of band Liouvillian as the dissipative counterpart of band Hamiltonian, and show a method to evaluate the topological order of its steady state. This is based on a generalization of the Chern number valid for general mixed states (referred to as density matrix Chern value), which witnesses topological order in a system coupled to external noise. Additionally, we study its relation with the electrical conductivity at finite temperature, which is not a topological property. Nonetheless, the density matrix Chern value represents the part of the conductivity which is topological due to the presence of quantum mixed edge states at finite temperature. To make our formalism concrete, we apply these concepts to the two-dimensional Haldane model in the presence of thermal dissipation, but our results hold for arbitrary dimensions and density matrices.

  14. Internal wave instability: Wave-wave versus wave-induced mean flow interactions

    E-Print Network [OSTI]

    Sutherland, Bruce

    , known as parametric sub- harmonic instability, results generally when a disturbance of one frequency imparts energy to disturbances of half that frequency.13,14 Generally, a plane periodic internal wave, energy from primary waves is transferred, for example, to waves with half frequency. Self

  15. Development of Silica Aerogel with Any Density

    E-Print Network [OSTI]

    M. Tabata; I. Adachi; T. Fukushima; H. Kawai; H. Kishimoto; A. Kuratani; H. Nakayama; S. Nishida; T. Noguchi; K. Okudaira; Y. Tajima; H. Yano; H. Yokogawa; H. Yoshida

    Abstract–New production methods of silica aerogel with high and low refractive indices have been developed. A very slow shrinkage of alcogel at room temperature has made possible producing aerogel with high refractive indices of up to 1.265 without cracks. Even higher refractive indices than 1.08, the transmission length of the aerogel obtained from this technique has been measured to be about 10 to 20 mm at 400 nm wave length. A mold made of alcogel which endures shrinkage in the supercritical drying process has provided aerogel with the extremely low density of 0.009g/cm 3, which corresponds to the refractive index of 1.002. We have succeeded producing aerogel with a wide range of densities. I.

  16. Recent Fast Wave Coupling and Heating Studies on NSTX, with Possible Implications for ITER

    SciTech Connect (OSTI)

    J.C. Hosea, R.E. Bell, E. Feibush, R.W. Harvey, E.F. Jaeger, B.P LeBlanc, R. Maingi, C.K. Phillips, L. Roquemore, P.M. Ryan, G. Taylor, K. Tritz, E.J. Valeo, J. Wilgen, J.R. Wilson, and the NSTX Team

    2009-07-21T23:59:59.000Z

    The goal of the high harmonic fast wave (HHFW) research on NSTX is to maximize the coupling of RF power to the core of the plasma by minimizing the coupling of RF power to edge loss processes. HHFW core plasma heating efficiency in helium and deuterium L-mode discharges is found to improve markedly on NSTX when the density 2 cm in front of the antenna is reduced below that for the onset of perpendicular wave propagation (nonset ? B*k|| 2/?). In NSTX, the observed RF power losses in the plasma edge are driven in the vicinity of the antenna as opposed to resulting from multi-pass edge damping. PDI surface losses through ion-electron collisions are estimated to be significant. Recent spectroscopic measurements suggest that additional PDI losses could be caused by the loss of energetic edge ions on direct loss orbits and perhaps result in the observed clamping of the edge rotation. Initial deuterium H-mode heating studies reveal that core heating is degraded at lower k? (- 8 m-1 relative to 13 m-1) as for the Lmode case at elevated edge density. Fast visible camera images clearly indicate that a major edge loss process is occurring from the plasma scrape off layer (SOL) in the vicinity of the antenna and along the magnetic field lines to the lower outer divertor plate. Large type I ELMs, which are observed at both k? values, appear after antenna arcs caused by precursor blobs, low level ELMs, or dust. For large ELMs without arcs, the source reflection coefficients rise on a 0.1 ms time scale, which indicates that the time derivative of the reflection coefficient can be used to discriminate between arcs and ELMs.

  17. Dust-Acoustic Waves: Visible Sound Waves Robert L. Merlino

    E-Print Network [OSTI]

    Merlino, Robert L.

    Dust-Acoustic Waves: Visible Sound Waves Robert L. Merlino Department of Physics and Astronomy with their announcement that: "We find that a new type of sound wave, namely, the dust-acoustic waves, can appear" [1 and experimental work on dust acoustic waves is given. The basic physics of the dust acoustic wave and some

  18. Author's personal copy Wave energy resources along the Hawaiian Island chain

    E-Print Network [OSTI]

    model Wave atlas Wave energy Wave power a b s t r a c t Hawaii's access to the ocean and remoteness from heights show good agreement with data from satellites and buoys. Bi-monthly median and percentile plots Elsevier Ltd. All rights reserved. 1. Introduction The Earth's changing climate, the increasing cost of oil

  19. Low Mach number simulation of a loaded standing-wave thermoacoustic engine

    E-Print Network [OSTI]

    Paris-Sud XI, Université de

    Low Mach number simulation of a loaded standing-wave thermoacoustic engine L. Maa , C. I. Weismana standing-wave thermoacoustic engine are performed using a low Mach number model. This work uses- wave thermoacoustic engine, the acoustic power developed is calculated and the efficiency is estimated

  20. Wave Energy Resource Assessment | Department of Energy

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

    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 DataDepartment of Energy Your DensityEnergy U.S.-China Electric Vehicle and03/02ReportWaste-to-Energy andAprilWater andWatershedWaveWave