National Library of Energy BETA

Sample records for tidal wave current

  1. Assessment of Projected Life-Cycle Costs for Wave, Tidal, Ocean Current,

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    and In-Stream Hydrokinetic Power | Department of Energy 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, and In-Stream Hydrokinetic Power Assessment of Projected Life-Cycle Costs for Wave, Tidal, Ocean Current, and In-Stream Hydrokinetic Power 16_life_revision_previsic_update.ppt (2.64 MB) More Documents & Publications 2014 Water Power Program Peer Review

  2. 12th Annual Wave & Tidal 2015

    Energy.gov [DOE]

    The UK is currently the undisputed global leader in marine energy, with more wave and tidal stream devices installed than the rest of the world combined. This leading position is built on an...

  3. Energy Department Announces $8 Million to Develop Advanced Components for Wave, Tidal, and Current Energy Systems

    Energy.gov [DOE]

    The Energy Department today announced $8 million in available funding to spur innovation in next-generation marine and hydrokinetic control and component technologies. In the United States, waves, tides, and ocean currents represent a largely untapped renewable energy resource that could provide clean, affordable energy to homes and businesses across the country's coastal regions.

  4. 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, ...

  5. Energy Department Awards More Than $20 Million for Wave and Tidal...

    Office of Environmental Management (EM)

    (MHK) energy systems, which generate electricity from ocean waves and tidal currents. ... To learn more about how MHK devices capture energy from waves, tides and currents, view ...

  6. European Wave and Tidal Energy Conference

    Energy.gov [DOE]

    The European Wave and Tidal Energy Conference (EWTEC) series are international, technical and scientific conferences, focussed on ocean renewable energy and widely respected for their commitment to...

  7. MHK Technologies/Uldolmok Pilot Tidal Current Power Plant | Open...

    OpenEI (Open Energy Information) [EERE & EIA]

    Uldolmok Pilot Tidal Current Power Plant < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Uldolmok Pilot Tidal Current Power Plant.jpg...

  8. Tapping into Wave and Tidal Ocean Power: 15% Water Power by 2030 |

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Department of Energy into Wave and Tidal Ocean Power: 15% Water Power by 2030 Tapping into Wave and Tidal Ocean Power: 15% Water Power by 2030 January 27, 2012 - 11:30am Addthis A map generated by Georgia Tech's tidal energy resource database shows mean current speed of tidal streams. The East Coast, as shown above, has strong tides that could be tapped to produce energy. | Photo courtesy of Georgia Institute of Technology A map generated by Georgia Tech's tidal energy resource database

  9. Hydropower, Wave and Tidal Technologies - Energy Innovation Portal

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Storage Geothermal Hydrogen and Fuel Cell Hydropower, Wave and Tidal Marketing Summaries (13) Industrial Technologies Solar Photovoltaic Solar Thermal Startup America Vehicles ...

  10. Energy Department Invests $16 Million to Harness Wave and Tidal Energy |

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Department of Energy 6 Million to Harness Wave and Tidal Energy Energy Department Invests $16 Million to Harness Wave and Tidal Energy August 29, 2013 - 2:35pm Addthis News Media Contact (202) 586-4940 WASHINGTON - As part of the Obama Administration's all-of-the-above strategy to deploy every available source of American energy, the Energy Department today announced $16 million for seventeen projects to help sustainably and efficiently capture energy from waves, tides and currents.

  11. Status of Wave and Tidal Power Technologies for the United States

    SciTech Connect

    Musial, W.

    2008-08-01

    This paper presents the status of marine applications for renewable energy as of 2008 from a U.S. perspective. Technologies examined include wave, tidal, and ocean current energy extraction devices.

  12. Hydropower, Wave and Tidal Technologies Available for Licensing - Energy

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Innovation Portal Hydropower, Wave and Tidal Site Map Printable Version Share this resource About Search Categories (15) Advanced Materials Biomass and Biofuels Building Energy Efficiency Electricity Transmission Energy Analysis Energy Storage Geothermal Hydrogen and Fuel Cell Hydropower, Wave and Tidal Marketing Summaries (13) Industrial Technologies Solar Photovoltaic Solar Thermal Startup America Vehicles and Fuels Wind Energy Partners (27) Visual Patent Search Success Stories Browse

  13. The environmental interactions of tidal and wave energy generation devices

    SciTech Connect

    Frid, Chris; Andonegi, Eider; Judd, Adrian; Rihan, Dominic; Rogers, Stuart I.; Kenchington, Ellen

    2012-01-15

    Global energy demand continues to grow and tidal and wave energy generation devices can provide a significant source of renewable energy. Technological developments in offshore engineering and the rising cost of traditional energy means that offshore energy resources will be economic in the next few years. While there is now a growing body of data on the ecological impacts of offshore wind farms, the scientific basis on which to make informed decisions about the environmental effects of other offshore energy developments is lacking. Tidal barrages have the potential to cause significant ecological impacts particularly on bird feeding areas when they are constructed at coastal estuaries or bays. Offshore tidal stream energy and wave energy collectors offer the scope for developments at varying scales. They also have the potential to alter habitats. A diversity of designs exist, including floating, mid-water column and seabed mounted devices, with a variety of moving-part configurations resulting in a unique complex of potential environmental effects for each device type, which are discussed to the extent possible. - Highlights: Black-Right-Pointing-Pointer We review the environmental impacts of tidal barrages and fences, tidal stream farms and wave energy capture devices. Black-Right-Pointing-Pointer Impacts on habitats, species and the water column, and effects of noise and electromagnetic fields are considered. Black-Right-Pointing-Pointer Tidal barrages can cause significant impacts on bird feeding areas when constructed at coastal estuaries or bays. Black-Right-Pointing-Pointer Wave energy collectors can alter water column and sea bed habitats locally and over large distances.

  14. Energy Department Awards More Than $20 Million for Wave and Tidal Energy Projects

    Energy.gov [DOE]

    The Energy Department today announced 10 organizations selected to receive more than $20 million in funding for new research, development, and demonstration projects that advance and monitor marine and hydrokinetic (MHK) energy systems, which generate electricity from ocean waves and tidal currents.

  15. Energy Department Announces Funding for Demonstration and Testing of Advanced Wave and Tidal Energy Technologies

    Energy.gov [DOE]

    The Energy Department today announced $10 million to strengthen the U.S. marine and hydrokinetic (MHK) energy industry, including wave and tidal energy sources.

  16. Ocean current wave interaction study

    SciTech Connect

    Hayes, J.G.

    1980-09-20

    A numerical model has been developed to incorporate refraction of ocean surface gravity waves by major ocean currents. The model is initialized with directional wave spectra and verified with aircraft synthetic aperture radar X band spectra, laser profilometer spectra, and pitch and roll buoy data. Data collected during the Marineland test experiment are used as surface truth observations for the wave-current study. Evidence of Gulf Stream refraction and trapping of surface waves as well as caustics in the current is shown and modeled assuming a nonuniform Gulf Stream distribution. Frequency and directional resolution of the wave spectral distribution and the current refraction patterns illustrates the need for further study of ocean current-wave interaction in wave refraction studies.

  17. Tidal | OpenEI Community

    OpenEI (Open Energy Information) [EERE & EIA]

    Submitted by Ocop(5) Member 15 July, 2014 - 07:07 MHK LCOE Reporting Guidance Draft Cost Current DOE LCOE numerical modeling Performance Tidal Wave To normalize competing...

  18. High-resolution velocimetry in energetic tidal currents using a convergent-beam acoustic Doppler profiler

    SciTech Connect

    Sellar, Brian; Harding, Samuel F.; Richmond, Marshall C.

    2015-07-16

    An array of convergent acoustic Doppler velocimeters has been developed and tested for the high resolution measurement of three-dimensional tidal flow velocities in an energetic tidal site. This configuration has been developed to increase spatial resolution of velocity measurements in comparison to conventional acoustic Doppler profilers (ADPs) which characteristically use diverging acoustic beams emanating from a single instrument. This is achieved using converging acoustic beams with a sample volume at the focal point of 0.03 m3. The array is also able to simultaneously measure three-dimensional velocity components in a profile throughout the water column, and as such is referred to herein as a converging-beam acoustic Doppler profiler (CADP). Mid-depth profiling is achieved through integration of the sensor platform with the operational Alstom 1MW DeepGen-IV Tidal Turbine. This proof-of-concept paper outlines system configuration and comparison to measurements provided by co-installed reference instrumentation. Comparison of CADP to standard ADP velocity measurements reveals a mean difference of 8 mm/s, standard deviation of 18 mm/s, and order-of-magnitude reduction in realizable length-scale. CADP focal point measurements compared to a proximal single-beam reference show peak cross-correlation coefficient of 0.96 over 4.0 s averaging period and a 47% reduction in Doppler noise. The dual functionality of the CADP as a profiling instrument with a high resolution focal point make this configuration a unique and valuable advancement in underwater velocimetry enabling improved turbulence, resource and structural loading quantification and validation of numerical simulations. Alternative modes of operation have been implemented including noise-reducing bi-static sampling. Since waves are simultaneously measured it is expected that derivatives of this system will be a powerful tool in wave-current interaction studies.

  19. Gravitational waves from the collision of tidally disrupted stars with massive black holes

    SciTech Connect

    East, William E.

    2014-11-10

    We use simulations of hydrodynamics coupled with full general relativity to investigate the gravitational waves produced by a star colliding with a massive black hole when the star's tidal disruption radius lies far outside of the black hole horizon. We consider both main-sequence and white-dwarf compaction stars, and nonspinning black holes, as well as those with near-extremal spin. We study the regime in between where the star can be accurately modeled by a point particle, and where tidal effects completely suppress the gravitational wave signal. We find that nonnegligible gravitational waves can be produced even when the star is strongly affected by tidal forces, as well as when it collides with large angular momentum. We discuss the implications that these results have for the potential observation of gravitational waves from these sources with future detectors.

  20. Reference Model #1 - Tidal Energy: Resource Dr. Brian Polagye

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    1 is a tidal turbine operating in a narrow, tidal channel. ... Meteorological currents include wave- and wind-induced ... This also reduces ensemble Doppler noise (n ensemble ) by a ...

  1. Feasibility of Tidal and Ocean Current Energy in False Pass,...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    and heat to meet long-term fossil fuel use reduction goals, ... Using the current price of 3.53 and the average ... are high, the low load forecast scenario increases ...

  2. Feasibility of Tidal and Ocean Current Energy in False Pass, Aleutian Islands, Alaska final report

    SciTech Connect

    Wright, Bruce Albert

    2014-05-07

    The Aleutian Pribilof Islands Association was awarded a U.S. Department of Energy Tribal Energy Program grant (DE-EE0005624) for the Feasibility of Tidal and Ocean Current Energy in False Pass, Aleutian Islands, Alaska (Project). The goal of the Project was to perform a feasibility study to determine if a tidal energy project would be a viable means to generate electricity and heat to meet long-term fossil fuel use reduction goals, specifically to produce at least 30% of the electrical and heating needs of the tribally-owned buildings in False Pass. The Project Team included the Aleut Region organizations comprised of the Aleutian Pribilof Island Association (APIA), and Aleutian Pribilof Island Community Development Association (APICDA); the University of Alaska Anchorage, ORPC Alaska a wholly-owned subsidiary of Ocean Renewable Power Company (ORPC), City of False Pass, Benthic GeoScience, and the National Renewable Energy Laboratory (NREL). The following Project objectives were completed: collected existing bathymetric, tidal, and ocean current data to develop a basic model of current circulation at False Pass, measured current velocities at two sites for a full lunar cycle to establish the viability of the current resource, collected data on transmission infrastructure, electrical loads, and electrical generation at False Pass, performed economic analysis based on current costs of energy and amount of energy anticipated from and costs associated with the tidal energy project conceptual design and scoped environmental issues. Utilizing circulation modeling, the Project Team identified two target sites with strong potential for robust tidal energy resources in Isanotski Strait and another nearer the City of False Pass. In addition, the Project Team completed a survey of the electrical infrastructure, which identified likely sites of interconnection and clarified required transmission distances from the tidal energy resources. Based on resource and electrical data

  3. Structural Design of a Horizontal-Axis Tidal Current Turbine Composite Blade

    SciTech Connect

    Bir, G. S.; Lawson, M. J.; Li, Y.

    2011-10-01

    This paper describes the structural design of a tidal composite blade. The structural design is preceded by two steps: hydrodynamic design and determination of extreme loads. The hydrodynamic design provides the chord and twist distributions along the blade length that result in optimal performance of the tidal turbine over its lifetime. The extreme loads, i.e. the extreme flap and edgewise loads that the blade would likely encounter over its lifetime, are associated with extreme tidal flow conditions and are obtained using a computational fluid dynamics (CFD) software. Given the blade external shape and the extreme loads, we use a laminate-theory-based structural design to determine the optimal layout of composite laminas such that the ultimate-strength and buckling-resistance criteria are satisfied at all points in the blade. The structural design approach allows for arbitrary specification of the chord, twist, and airfoil geometry along the blade and an arbitrary number of shear webs. In addition, certain fabrication criteria are imposed, for example, each composite laminate must be an integral multiple of its constituent ply thickness. In the present effort, the structural design uses only static extreme loads; dynamic-loads-based fatigue design will be addressed in the future. Following the blade design, we compute the distributed structural properties, i.e. flap stiffness, edgewise stiffness, torsion stiffness, mass, moments of inertia, elastic-axis offset, and center-of-mass offset along the blade. Such properties are required by hydro-elastic codes to model the tidal current turbine and to perform modal, stability, loads, and response analyses.

  4. Three-dimensional Numerical Analysis on Blade Response of Vertical Axis Tidal Current Turbine Under Operational Condition

    SciTech Connect

    Li, Ye; Karri, Naveen K.; Wang, Qi

    2014-04-30

    Tidal power as a large-scale renewable source of energy has been receiving significant attention recently because of its advantages over the wind and other renewal energy sources. The technology used to harvest energy from tidal current is called a tidal current turbine. Though some of the principles of wind turbine design are applicable to tidal current turbines, the design of latter ones need additional considerations like cavitation damage, corrosion etc. for the long-term reliability of such turbines. Depending up on the orientation of axis, tidal current turbines can be classified as vertical axis turbines or horizontal axis turbines. Existing studies on the vertical axis tidal current turbine focus more on the hydrodynamic aspects of the turbine rather than the structural aspects. This paper summarizes our recent efforts to study the integrated hydrodynamic and structural aspects of the vertical axis tidal current turbines. After reviewing existing methods in modeling tidal current turbines, we developed a hybrid approach that combines discrete vortex method -finite element method that can simulate the integrated hydrodynamic and structural response of a vertical axis turbine. This hybrid method was initially employed to analyze a typical three-blade vertical axis turbine. The power coefficient was used to evaluate the hydrodynamic performance, and critical deflection was considered to evaluate the structural reliability. A sensitivity analysis was also conducted with various turbine height-to-radius ratios. The results indicate that both the power output and failure probability increase with the turbine height, suggesting a necessity for optimal design. An attempt to optimize a 3-blade vertical axis turbine design with hybrid method yielded a ratio of turbine height to radius (H/R) about 3.0 for reliable maximum power output.

  5. Wave | OpenEI Community

    OpenEI (Open Energy Information) [EERE & EIA]

    Submitted by Ocop(5) Member 15 July, 2014 - 07:07 MHK LCOE Reporting Guidance Draft Cost Current DOE LCOE numerical modeling Performance Tidal Wave To normalize competing...

  6. Current | OpenEI Community

    OpenEI (Open Energy Information) [EERE & EIA]

    Submitted by Ocop(5) Member 15 July, 2014 - 07:07 MHK LCOE Reporting Guidance Draft Cost Current DOE LCOE numerical modeling Performance Tidal Wave To normalize competing...

  7. Fast wave current drive in DEMO

    SciTech Connect

    Lerche, E.; Van Eestera, D.; Messiaen, A.; Collaboration: EFDA-PPPT Contributors

    2014-02-12

    The ability to non-inductively drive a large fraction of the toroidal plasma current in magnetically confined plasmas is an essential requirement for steady state fusion reactors such as DEMO. Besides neutral beam injection (NBI), electron-cyclotron resonance heating (ECRH) and lower hybrid wave heating (LH), ion-cyclotron resonance heating (ICRH) is a promising candidate to drive current, in particular at the high temperatures expected in fusion plasmas. In this paper, the current drive (CD) efficiencies calculated with coupled ICRF wave / CD numerical codes for the DEMO-1 design case (R{sub 0}=9m, B{sub 0}=6.8T, a{sub p}=2.25m) [1] are presented. It will be shown that although promising CD efficiencies can be obtained in the usual ICRF frequency domain (20-100MHz) by shifting the dominant ion-cyclotron absorption layers to the high-field side, operation at higher frequencies (100-300MHz) has a stronger CD potential, provided the parasitic RF power absorption of the alpha particles can be minimized.

  8. Field Measurements at River and Tidal Current Sites for Hydrokinetic Energy Development: Best Practices Manual

    SciTech Connect

    Neary, Vincent S; Gunawan, Budi

    2011-09-01

    In this report, existing data collection techniques and protocols for characterizing open channel flows are reviewed and refined to further address the needs of the MHK industry. The report provides an overview of the hydrodynamics of river and tidal channels, and the working principles of modern acoustic instrumentation, including best practices in remote sensing methods that can be applied to hydrokinetic energy site characterization. Emphasis is placed upon acoustic Doppler velocimeter (ADV) and acoustic-Doppler current profiler (ADCP) instruments, as these represent the most practical and economical tools for use in the MHK industry. Incorporating the best practices as found in the literature, including the parameters to be measured, the instruments to be deployed, the instrument deployment strategy, and data post-processing techniques. The data collected from this procedure aims to inform the hydro-mechanical design of MHK systems with respect to energy generation and structural loading, as well as provide reference hydrodynamics for environmental impact studies. The standard metrics and protocols defined herein can be utilized to guide field experiments with MHK systems.

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

    DOEpatents

    Gorlov, Alexander M.

    1991-01-01

    The invention, which provides a system for harnessing power from current flow or tidal movement in a body of water, comprises first and second hydro-pneumatic chambers each having ingress and egress below the water surface near the river or ocean floor and water gates operative to open or seal the ports to the passage of water. In an exemplary embodiment, the gates are sychronized by shafts so that the ingress ports of each chamber are connected to the egress ports of each other chamber. Thus, one set of gates is closed, while the other is open, thereby allowing water to flow into one chamber and build air pressure therein and allowing water to flow out of the other chamber and create a partial vacuum therein. A pipe connects the chambers, and an air turbine harnesses the air movement within the pipe. When water levels are equilibrated, the open set of gates is closed by a counterweight, and the other set is allowed to open by natural force of the water differential. The water gates may be comprised of a plurality of louvers which are ganged for simultaneous opening and closing. The system is designed to operate with air turbines or other pneumatic devices. Its design minimizes construction cost and environmental impact, yet provides a clean renewable energy source.

  10. Renewables in Alaska Native Villages: Feasibility of Tidal and Ocean Current Energy in False Pass, Aleutian Islands, Alaska

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Funding: Feasibility of Tidal and Ocean Current Energy in False Pass, Aleutian Islands, AK Bruce Wright, APIA Monty Worthington, ORPC Wright, B. A., J. W. Short, T. J. Weingartner and P. J. Anderson. 2000. The Gulf of Alaska.. Pp 373-384 in Sheppard, C. R. C., ed., Seas at the Millennium: An Environmental, Evaluation Volume I Regional Chapters: Europe, The Americas and Wes Africa. Pergammon Press, Elsevier, Amsterdam. Aleutian Pribilof Islands Regional Energy Summit April 24-25, 2010 Anchorage,

  11. Penetration of lower hybrid current drive waves in tokamaks

    SciTech Connect

    Horton, W.; Aix-Marseille University, 58, Bd Charles Livon, 13284 Marseille ; Goniche, M.; Peysson, Y.; Decker, J.; Ekedahl, A.; Litaudon, X.

    2013-11-15

    Lower hybrid (LH) ray propagation in toroidal plasma is shown to be controlled by combination of the azimuthal spectrum launched by the antenna, the poloidal variation of the magnetic field, and the scattering of the waves by the drift wave fluctuations. The width of the poloidal and radial radio frequency wave spectrum increases rapidly as the rays penetrate into higher density and scatter from the drift waves. The electron temperature gradient (ETG) spectrum is particularly effective in scattering the LH waves due to its comparable wavelengths and phase velocities. ETG turbulence is also driven by the radial gradient of the electron current profile giving rise to an anomalous viscosity spreading the LH driven plasma currents. The LH wave scattering is derived from a Fokker-Planck equation for the distribution of the ray trajectories with diffusivities derived from the drift wave fluctuations. The condition for chaotic diffusion for the rays is derived. The evolution of the poloidal and radial mode number spectrum of the lower hybrid waves are both on the antenna spectrum and the spectrum of the drift waves. Antennas launching higher poloidal mode number spectra drive off-axis current density profiles producing negative central shear [RS] plasmas with improved thermal confinement from ETG transport. Core plasma current drive requires antennas with low azimuthal mode spectra peaked at m = 0 azimuthal mode numbers.

  12. HEATING AND CURRENT DRIVE IN NSTX WITH ELECTRON BERNSTEIN WAVES AND HIGH HARMONIC FAST WAVES

    SciTech Connect

    Ram, Abhay K

    2010-06-14

    A suitable theoretical and computational framework for studying heating and current drive by electron Bernstein waves in the National Spherical Torus Experiment has been developed. This framework can also be used to study heating and current drive by electron Bernstein waves in spherical tori and other magnetic confinement devices. It is also useful in studying the propagation and damping of electron cyclotron waves in the International Thermonuclear Experimental Reactor

  13. Development and Verification of a Computational Fluid Dynamics Model of a Horizontal-Axis Tidal Current Turbine

    SciTech Connect

    Lawson, M. J.; Li, Y.; Sale, D. C.

    2011-10-01

    This paper describes the development of a computational fluid dynamics (CFD) methodology to simulate the hydrodynamics of horizontal-axis tidal current turbines. Qualitative measures of the CFD solutions were independent of the grid resolution. Conversely, quantitative comparisons of the results indicated that the use of coarse computational grids results in an under prediction of the hydrodynamic forces on the turbine blade in comparison to the forces predicted using more resolved grids. For the turbine operating conditions considered in this study, the effect of the computational timestep on the CFD solution was found to be minimal, and the results from steady and transient simulations were in good agreement. Additionally, the CFD results were compared to corresponding blade element momentum method calculations and reasonable agreement was shown. Nevertheless, we expect that for other turbine operating conditions, where the flow over the blade is separated, transient simulations will be required.

  14. Three-dimensional structures of equatorial waves and the resulting super-rotation in the atmosphere of a tidally locked hot Jupiter

    SciTech Connect

    Tsai, Shang-Min; Gu, Pin-Gao; Dobbs-Dixon, Ian

    2014-10-01

    Three-dimensional (3D) equatorial trapped waves excited by stellar isolation and the resulting equatorial super-rotating jet in a vertical stratified atmosphere of a tidally locked hot Jupiter are investigated. Taking the hot Jupiter HD 189733b as a fiducial example, we analytically solve linear equations subject to stationary stellar heating with a uniform zonal-mean flow included. We also extract wave information in the final equilibrium state of the atmosphere from our radiative hydrodynamical simulation for HD 189733b. Our analytic wave solutions are able to qualitatively explain the 3D simulation results. Apart from previous wave studies, investigating the vertical structure of waves allows us to explore new wave features such as the wavefronts tilts related to the Rossby-wave resonance as well as dispersive equatorial waves. We also attempt to apply our linear wave analysis to explain some numerical features associated with the equatorial jet development seen in the general circulation model by Showman and Polvani. During the spin-up phase of the equatorial jet, the acceleration of the jet can be in principle boosted by the Rossby-wave resonance. However, we also find that as the jet speed increases, the Rossby-wave structure shifts eastward, while the Kelvin-wave structure remains approximately stationary, leading to the decline of the acceleration rate. Our analytic model of jet evolution implies that there exists only one stable equilibrium state of the atmosphere, possibly implying that the final state of the atmosphere is independent of initial conditions in the linear regime. Limitations of our linear model and future improvements are also discussed.

  15. Development and Verification of a Computational Fluid Dynamics Model of a Horizontal-Axis Tidal Current Turbine

    SciTech Connect

    Lawson, Mi. J.; Li, Y.; Sale, D. C.

    2011-01-01

    This paper describes the development of a computational fluid dynamics (CFD) methodology to simulate the hydrodynamics of horizontal-axis tidal current turbines (HATTs). First, an HATT blade was designed using the blade element momentum method in conjunction with a genetic optimization algorithm. Several unstructured computational grids were generated using this blade geometry and steady CFD simulations were used to perform a grid resolution study. Transient simulations were then performed to determine the effect of time-dependent flow phenomena and the size of the computational timestep on the numerical solution. Qualitative measures of the CFD solutions were independent of the grid resolution. Conversely, quantitative comparisons of the results indicated that the use of coarse computational grids results in an under prediction of the hydrodynamic forces on the turbine blade in comparison to the forces predicted using more resolved grids. For the turbine operating conditions considered in this study, the effect of the computational timestep on the CFD solution was found to be minimal, and the results from steady and transient simulations were in good agreement. Additionally, the CFD results were compared to corresponding blade element momentum method calculations and reasonable agreement was shown. Nevertheless, we expect that for other turbine operating conditions, where the flow over the blade is separated, transient simulations will be required.

  16. Wave Energy Converter (WEC) Array Effects on Wave Current and Sediment Circulation: Monterey Bay CA.

    SciTech Connect

    Roberts, Jesse D.; Jones, Craig; Magalen, Jason

    2014-09-01

    The goal s of this study were to develop tools to quantitatively characterize environments where wave energy converter ( WEC ) devices may be installed and to assess e ffects on hydrodynamics and lo cal sediment transport. A large hypothetical WEC array was investigated using wave, hydrodynamic, and sediment transport models and site - specific average and storm conditions as input. The results indicated that there were significant changes in sediment s izes adjacent to and in the lee of the WEC array due to reduced wave energy. The circulation in the lee of the array was also altered; more intense onshore currents were generated in the lee of the WECs . In general, the storm case and the average case show ed the same qualitative patterns suggesting that these trends would be maintained throughout the year. The framework developed here can be used to design more efficient arrays while minimizing impacts on nearshore environmen ts.

  17. tidal turbines

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    tidal turbines - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us ... Stationary Power Energy Conversion Efficiency Solar Energy Wind Energy Water Power ...

  18. Large-Eddy Simulation Study of Wake Propagation and Power Production in an Array of Tidal-Current Turbines: Preprint

    SciTech Connect

    Churchfield, M. J.; Li, Y.; Moriarty, P. J.

    2012-07-01

    This paper presents our initial work in performing large-eddy simulations of tidal turbine array flows. First, a horizontally-periodic precursor simulation is performed to create turbulent flow data. Then that data is used as inflow into a tidal turbine array two rows deep and infinitely wide. The turbines are modeled using rotating actuator lines, and the finite-volume method is used to solve the governing equations. In studying the wakes created by the turbines, we observed that the vertical shear of the inflow combined with wake rotation causes lateral wake asymmetry. Also, various turbine configurations are simulated, and the total power production relative to isolated turbines is examined. Staggering consecutive rows of turbines in the simulated configurations allows the greatest efficiency using the least downstream row spacing. Counter-rotating consecutive downstream turbines in a non-staggered array shows a small benefit. This work has identified areas for improvement, such as the use of a larger precursor domain to better capture elongated turbulent structures, the inclusion of salinity and temperature equations to account for density stratification and its effect on turbulence, improved wall shear stress modelling, and the examination of more array configurations.

  19. List of Tidal Energy Incentives | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Coal with CCS Concentrating Solar Power Energy Storage Fuel Cells Geothermal Electric Natural Gas Nuclear Tidal Energy Wave Energy Wind energy BiomassBiogas Hydroelectric...

  20. Modeling of high harmonic fast wave current drive on EAST tokamak

    SciTech Connect

    Li, J. C.; Gong, X. Y. Li, F. Y.; Dong, J. Q.; Gao, Q. D.; Zhang, N.

    2015-10-15

    High harmonic fast waves (HHFW) are among the candidates for non-inductive current drive (CD), which is essential for long-pulse or steady-state operation of tokamaks. Current driven with HHFW in EAST tokamak plasmas is numerically studied. The HHFW CD efficiency is found to increase non-monotonically with the wave frequency, and this phenomenon is attributed to the multi-pass absorption of HHFW. The sensitivity of CD efficiency to the value of the parallel refraction index of the launched wave is confirmed. The quasilinear effects, assessed as significant in HHFW current drive with the GENRAY/CQL3D package, cause a significant increase in CD efficiency as RF power is increased, which is very different from helicon current drive. Simulations for a range of toroidal dc electric fields, in combination with a range of fast wave powers, are also presented and indicate that the presence of the DC field can also enhance the CD efficiency.

  1. Dependence of synergy current driven by lower hybrid wave and electron cyclotron wave on the frequency and parallel refractive index of electron cyclotron wave for Tokamaks

    SciTech Connect

    Huang, J.; Chen, S. Y. Tang, C. J.; Key Laboratory of High Energy Density Physics and Technology of Ministry of Education, Sichuan University, Chengdu 610064

    2014-01-15

    The physical mechanism of the synergy current driven by lower hybrid wave (LHW) and electron cyclotron wave (ECW) in tokamaks is investigated using theoretical analysis and simulation methods in the present paper. Research shows that the synergy relationship between the two waves in velocity space strongly depends on the frequency ω and parallel refractive index N{sub //} of ECW. For a given spectrum of LHW, the parameter range of ECW, in which the synergy current exists, can be predicted by theoretical analysis, and these results are consistent with the simulation results. It is shown that the synergy effect is mainly caused by the electrons accelerated by both ECW and LHW, and the acceleration of these electrons requires that there is overlap of the resonance regions of the two waves in velocity space.

  2. Dynamic control of spin wave spectra using spin-polarized currents

    SciTech Connect

    Wang, Qi; Zhang, Huaiwu Tang, Xiaoli; Bai, Feiming; Zhong, Zhiyong; Fangohr, Hans

    2014-09-15

    We describe a method of controlling the spin wave spectra dynamically in a uniform nanostripe waveguide through spin-polarized currents. A stable periodic magnetization structure is observed when the current flows vertically through the center of nanostripe waveguide. After being excited, the spin wave is transmitted at the sides of the waveguide. Numerical simulations of spin-wave transmission and dispersion curves reveal a single, pronounced band gap. Moreover, the periodic magnetization structure can be turned on and off by the spin-polarized current. The switching process from full rejection to full transmission takes place within less than 3?ns. Thus, this type magnonic waveguide can be utilized for low-dissipation spin wave based filters.

  3. DOE Science Showcase - Tidal Energy | OSTI, US Dept of Energy Office of

    Office of Scientific and Technical Information (OSTI)

    Scientific and Technical Information DOE Science Showcase - Tidal Energy Point absorbers generate electricity by converting the energy in waves using a float that rides the waves and is attached to a moored conversion device. The Department of Energy's Water Power Program Tapping into Wave and Tidal Ocean Power: 15% Water Power by 2030, Energy.gov News Assessment of Energy Production Potential from Tidal Streams in the United States, Energy Citations Database Georgia Tech's Tidal Energy

  4. Co-counter asymmetry in fast wave heating and current drive and profile control in NSTX

    SciTech Connect

    Jaeger, E.F.; Carter, M.D.; Berry, L.A.; Batchelor, D.B.; Ryan, P.M.; Forest, C.B.; Weitzner, H.; Majeski, R.

    1997-08-01

    In this paper, full-wave ICRF coupling models are applied to understand the difference in plasma response when antenna arrays are phased to drive currents co and counter to the plasma current. The source of this difference lies in the natural up-down asymmetry of the antenna`s radiated power spectrum caused by Hall currents. When a poloidal field is applied, this up-down asymmetry acquires a toroidal component. The result is that plasma absorption (i.e., antenna loading) is shifted or skewed toward the co-current drive direction, independent of the direction of the magnetic field. When waves are launched to drive current counter to the plasma current, electron heating and current profiles are more peaked on axis, and this peaking becomes more pronounced at lower toroidal magnetic fields.

  5. Near-surface current meter array measurements of internal gravity waves

    SciTech Connect

    Jones, H.B.E.

    1994-11-15

    We have developed various processing algorithms used to estimate the wave forms produced by hydrodynamic Internal Waves. Furthermore, the estimated Internal Waves are used to calculate the Modulation Transfer Function (MTF) which relates the current and strain rate subsurface fields to surface scattering phenomenon imaged by radar. Following a brief discussion of LLNL`s measurement platform (a 10 sensor current meter array) we described the generation of representative current and strain rate space-time images from measured or simulated data. Then, we present how our simulation capability highlighted limitations in estimating strain rate. These limitations spurred the application of beamforming techniques to enhance our estimates, albeit at the expense of collapsing our space-time images to 1-D estimates. Finally, we discuss progress with regard to processing the current meter array data captured during the recent Loch Linnhe field trials.

  6. DOE Science Showcase - Tidal Energy | OSTI, US Dept of Energy...

    Office of Scientific and Technical Information (OSTI)

    DOE Science Showcase - Tidal Energy Point absorbers generate electricity by converting the energy in waves using a float that rides the waves and is attached to a moored conversion ...

  7. New Interactive Map Reveals U.S. Tidal Energy Resources | Department of

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Energy Interactive Map Reveals U.S. Tidal Energy Resources New Interactive Map Reveals U.S. Tidal Energy Resources July 7, 2011 - 10:50am Addthis A map generated by Georgia Tech's tidal energy resource database shows mean current speed of tidal streams | Source: Georgia Institute of Technology A map generated by Georgia Tech's tidal energy resource database shows mean current speed of tidal streams | Source: Georgia Institute of Technology Michael Reed Michael Reed Director, Technical and

  8. Wave–current interaction in the presence of a three-dimensional bathymetry: Deep water wave focusing in opposing current conditions

    SciTech Connect

    Rey, V. Charland, J. Touboul, J.

    2014-09-15

    Large scale experiments were carried out in the Ocean Engineering Basin FIRST, France. A tri-dimensional bathymetry consisting of two symmetrical submerged mounds was displayed on the flat bed on both sides of the basin. Regular waves of frequency corresponding to deep water conditions above the bathymetry were generated in opposing current conditions. A strong tri-dimensional behaviour is observed for the wave amplitude, leading to a strong focusing (up to twice the incident amplitude) of the wave energy towards the central deeper zone. This amplification cannot be ascribed to the increase of the current intensity in the main wave direction, nor to a current gradient normally to the wave direction. A wave phase gradient, normal to its main direction, is observed up-wave (or downstream) the mounds. This phase lag depends on the wave amplitude, it is the higher for the moderate amplitude case. The experimental data are compared with calculations of a refraction-diffraction model assuming a depth-averaged current. If the model qualitatively predicts the wave amplification in the centerline of the basin, discrepancies are observed in the vicinity of the depth changes. The observed mean current vertical profile shape is then supposed to play a significant role in the wave focusing, especially near the steep slopes down-stream the mounds. In addition, the waves are found to modify substantially both horizontal and vertical current fields.

  9. Tidal Electric | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Tidal Electric Place: London, Greater London, United Kingdom Zip: SW19 8UY Product: Developed a technology named 'tidal lagoons' to build tidal electric projects. Coordinates:...

  10. Numerical studies of electron cyclotron wave current drive on HL-2A tokamak

    SciTech Connect

    Li, J. C.; Gong, X. Y.; Dong, J. Q.; Song, S. D.; Gao, Q. D.; Zheng, P. W.; Du, D.

    2015-06-15

    The electron cyclotron wave (ECW) current drive (CD) for the HL-2A tokamak is investigated numerically with a new ray-tracing and Fokker-Planck code. The code is benchmarked with other well-tested linear and quasilinear codes and is then used to study the electron cyclotron current drive on the HL-2A tokamak. The wave propagation, power deposition, and driven-current profiles are presented. The effect of electron trapping is also assessed. It is found that quasilinear effects are negligible at the present ECW power levels and that when both waves are injected at an angle of 20° on the plasma equatorial plane, the CD efficiency for the HL-2A saturates at ∼0.029 × 10{sup 20 }A/W/m{sup 2} and ∼0.020 × 10{sup 20 }A/W/m{sup 2} for the 0.5 MW/68 GHz first harmonic ordinary (O1) and 1 MW/140 GHz second harmonic extraordinary (X2) modes, respectively. The effects of the plasma density, temperature, and wave-launching position on the driven current are also investigated analytically and numerically.

  11. Filamentation instability of current-driven dust ion-acoustic waves in a collisional dusty plasma

    SciTech Connect

    Niknam, A. R. [Laser and Plasma Research Institute, Shahid Beheshti University, G.C., Tehran 19839-63113 (Iran, Islamic Republic of); Haghtalab, T.; Khorashadizadeh, S. M. [Physics Department, Birjand University, Birjand 97179-63384 (Iran, Islamic Republic of)

    2011-11-15

    A theoretical investigation has been made of the dust ion-acoustic filamentation instability in an unmagnetized current-driven dusty plasma by using the Lorentz transformation formulas. The effect of collision between the charged particles with neutrals and their thermal motion on this instability is considered. Developing the filamentation instability of the current-driven dust ion-acoustic wave allows us to determine the period and the establishment time of the filamentation structure and threshold for instability development.

  12. Whistlers, helicons, and lower hybrid waves: The physics of radio frequency wave propagation and absorption for current drive via Landau damping

    SciTech Connect

    Pinsker, R. I.

    2015-09-15

    This introductory-level tutorial article describes the application of plasma waves in the lower hybrid range of frequencies (LHRF) for current drive in tokamaks. Wave damping mechanisms in a nearly collisionless hot magnetized plasma are briefly described, and the connections between the properties of the damping mechanisms and the optimal choices of wave properties (mode, frequency, wavelength) are explored. The two wave modes available for current drive in the LHRF are described and compared. The terms applied to these waves in different applications of plasma physics are elucidated. The character of the ray paths of these waves in the LHRF is illustrated in slab and toroidal geometries. Applications of these ideas to experiments in the DIII-D tokamak are discussed.

  13. MHK Technologies/KESC Tidal Generator | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Technology Resource Click here CurrentTidal Technology Type Click here Axial Flow Turbine Technology Readiness Level Click here TRL 1-3: Discovery Concept Definition Early...

  14. MHK Projects/Clarence Strait Tidal Energy Project | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Project Country Australia Project Resource Click here Current Tidal Project Nearest Body of Water Clarence Strait Coordinates -12.083533792616, 131.04972839355 Project...

  15. Clarence Strait Tidal Energy Project, Tenax Energy Tropical Tidal...

    OpenEI (Open Energy Information) [EERE & EIA]

    Clarence Strait Tidal Energy Project, Tenax Energy Tropical Tidal Test Centre, Jump to: navigation, search 1 Retrieved from "http:en.openei.orgwindex.php?titleClarenceStrai...

  16. Electron Bernstein wave-bootstrap current synergy in the National Spherical Torus Experiment

    SciTech Connect

    Harvey, R.W.; Taylor, G.

    2005-05-15

    Current driven by electron Bernstein waves (EBW) and by the electron bootstrap effect are calculated separately and concurrently with a kinetic code to determine the degree of synergy between them. A target {beta}=40% NSTX [M. Ono, S. Kaye, M. Peng et al., Proceedings of the 17th IAEA Fusion Energy Conference, edited by M. Spak (IAEA, Vienna, Austria, 1999), Vol. 3, p. 1135] plasma is examined. A simple bootstrap model in the collisional-quasilinear CQL3D Fokker-Planck code (National Technical Information Service document No. DE93002962) is used in these studies: the transiting electron distributions are connected in velocity space at the trapped-passing boundary to trapped-electron distributions that are displaced radially by a half-banana-width outwards/inwards for the co-passing/counter-passing regions. This model agrees well with standard bootstrap current calculations over the outer 60% of the plasma radius. Relatively small synergy net bootstrap current is obtained for EBW power up to 4 MW. Locally, bootstrap current density increases in proportion to increased plasma pressure, and this effect can significantly affect the radial profile of driven current.

  17. WaveDyn: A Design Tool for Performance & Operational Loads Modeling...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    ...Core Expertise: Dedicated Software * Waves: Resource assessment and site data ... Tidal Bladed WaveFarmer TidalFarmer Waves Tides O2M O2C GH SCADA Developer's ...

  18. Spectral analysis of the efficiency of vertical mixing in the deep ocean due to interaction of tidal currents with a ridge running down a continental slope

    SciTech Connect

    Ibragimov, Ranis N.; Tartakovsky, Alexandre M.

    2014-10-29

    Efficiency of mixing, resulting from the reflection of an internal wave field imposed on the oscillatory background flow with a three-dimensional bottom topography, is investigated using a linear approximation. The radiating wave field is associated with the spectrum of the linear model, which consists of those mode numbers n and slope values α, for which the solution represents the internal waves of frequencies ω = nω0 radiating upwrad of the topography, where ω0 is the fundamental frequency at which internal waves are generated at the topography. The effects of the bottom topography and the earth’s rotation on the spectrum is analyzed analytically and numerically in the vicinity of the critical slope, which is a slope with the same angle to the horizontal as the internal wave characteristic. In this notation, θ is latitude, f is the Coriolis parameter and N is the buoyancy frequency, which is assumed to be a constant, which corresponds to the uniform stratification.

  19. Collaborative research: Dynamics of electrostatic solitary waves and their effects on current layers

    SciTech Connect

    Chen, Li-Jen

    2014-04-18

    The project has accomplished the following achievements including the goals outlined in the original proposal. Generation and measurements of Debye-scale electron holes in laboratory: We have generated by beam injections electron solitary waves in the LAPD experiments. The measurements were made possible by the fabrication of the state-of-the-art microprobes at UCLA to measure Debye-scale electric fields [Chiang et al., 2011]. We obtained a result that challenged the state of knowledge about electron hole generation. We found that the electron holes were not due to two-stream instability, but generated by a current-driven instability that also generated whistler-mode waves [Lefebvre et al., 2011, 2010b]. Most of the grant supported a young research scientist Bertrand Lefebvre who led the dissemination of the laboratory experimental results. In addition to two publications, our work relevant to the laboratory experiments on electron holes has resulted in 7 invited talks [Chen, 2007, 2009; Pickett et al., 2009a; Lefebvre et al., 2010a; Pickett et al., 2010; Chen et al., 2011c, b] (including those given by the co-I Jolene Pickett) and 2 contributed talks [Lefebvre et al., 2009b, a]. Discovery of elecctron phase-space-hole structure in the reconnection electron layer: Our theoretical analyses and simulations under this project led to the discovery of an inversion electric field layer whose phase-space signature is an electron hole within the electron diffusion layer in 2D anti-parallel reconnection [Chen et al., 2011a]. We carried out particle tracing studies to understand the electron orbits that result in the phase-space hole structure. Most importantly, we showed that the current density in the electron layer is limited in collisionless reconnection with negligible guide field by the cyclotron turning of meandering electrons. Comparison of electrostatic solitary waves in current layers observed by Cluster and in LAPD: We compared the ESWs observed in a supersubstorm

  20. Microsoft Word - RM1_Tidal Turbine_NREL Bir, Lawson, Li_2011...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    OMAE2011-50063 STRUCTURAL DESIGN OF A HORIZONTAL-AXIS TIDAL CURRENT TURBINE COMPOSITE BLADE ABSTRACT This paper describes the structural design of a tidal turbine composite blade. ...

  1. Wave

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    1 Summer 2001 Heat Wave This summer has proved to be downright hot in the Southern Great ... Not only is a summer heat wave uncomfortable, but it can also be ARM Facilities Newsletter ...

  2. Tidal Flow Turbulence Measurements

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    and it is a metric in the wind energy industry. For acoustic Dop surements, a noise-corrected expression of ... used to simulate tidal turbine perform quire speci cation ...

  3. The record of sea level rise by tidal sand bodies of the English Channel

    SciTech Connect

    Berne, S; Lericolais, G. (Ifremer, Plouzane, (France)); Lafont, F. (Universite d'Orsay (France))

    1990-05-01

    Improvements of very high resolution seismic reflection provide new information about internal structures of modern sand bodies. This allows us to reconstruct their recent history, which is related to the Holocene sea level rise. A major distinction is found between inner shelf sand bodies, dominated by autocyclic processes, and outer shelf sand bodies, where allocyclic processes are invoked to explain the apparent contradiction between internal structures and present-day dynamics. On the inner shelf, evidence of the migration of tidal dunes (sand waves) has been obtained by repeated surveys using accurate positioning systems. Major bounding surfaces are thought to result from the action of tidal current and/or from episodic storms. A rough estimation of the age of these sand bodies can be proposed. On the outer shelf, some dunes of the English Channel exhibit cross-beds indicative of a past net bed-load transport at the opposite of present days dynamics, inherited from different tidal conditions when sea level was between 20 and 40 m lower. Some large tidal sand banks (e.g., the Sark Bank near the Channel Islands) display a more complicated pattern. The upper part of the sand bank is the result of the migration of very large dunes climbing at positive angles, whereas the lower part shows major erosional surfaces, attributed to the action of storms during lower sea levels.

  4. Method for estimation of ocean current velocity from satellite images

    SciTech Connect

    Mollo-Christensen, E.; Cornillon, P.; Da S. Mascarenhas, A. Jr.

    1981-05-08

    Barotropic instability waves on a shear interface propagate at the average speed of the water on the two sides. Assuming the instability to be excited by tidal oscillations, the phase speed is the wavelength divided by the tidal period. If the water is at rest on one side of the shear layer the current speed on the other side can be calculated. This method, applied to the Gulf Stream beyond Cape Hatteras as seen in satellite images, gives estimates of current speed in general agreement with in situ observations.

  5. Tidal energy site resource assessment in the East River tidal strait, near Roosevelt Island, New York, New York

    SciTech Connect

    Gunawan, Budi; Neary, Vincent S.; Colby, Jonathan

    2014-06-22

    This study demonstrates a site resource assessment to examine the temporal variation of the mean current, turbulence intensities, and power densities for a tidal energy site in the East River tidal strait. These variables were derived from two-months of acoustic Doppler velocimeter (ADV) measurements at the design hub height of the Verdant Power Gen5 hydrokinetic turbine. The study site is a tidal strait that exhibits semi-diurnal tidal current characteristics, with a mean horizontal current speed of 1.4 m s-1, and turbulence intensity of 15% at a reference mean current of 2 m s-1. Flood and ebb flow directions are nearly bi-directional, with higher current magnitude during flood tide, which skews the power production towards the flood tide period. The tidal hydrodynamics at the site are highly regular, as indicated by the tidal current time series that resembles a sinusoidal function. This study also shows that the theoretical force and power densities derived from the current measurements can significantly be influenced by the length of the time window used for averaging the current data. Furthermore, the theoretical power density at the site, derived from the current measurements, is one order of magnitude greater than that reported in the U.S. national resource assessment. As a result, this discrepancy highlights the importance of conducting site resource assessments based on measurements at the tidal energy converter device scale.

  6. Tidal energy site resource assessment in the East River tidal strait, near Roosevelt Island, New York, New York

    DOE PAGES [OSTI]

    Gunawan, Budi; Neary, Vincent S.; Colby, Jonathan

    2014-06-22

    This study demonstrates a site resource assessment to examine the temporal variation of the mean current, turbulence intensities, and power densities for a tidal energy site in the East River tidal strait. These variables were derived from two-months of acoustic Doppler velocimeter (ADV) measurements at the design hub height of the Verdant Power Gen5 hydrokinetic turbine. The study site is a tidal strait that exhibits semi-diurnal tidal current characteristics, with a mean horizontal current speed of 1.4 m s-1, and turbulence intensity of 15% at a reference mean current of 2 m s-1. Flood and ebb flow directions are nearlymore » bi-directional, with higher current magnitude during flood tide, which skews the power production towards the flood tide period. The tidal hydrodynamics at the site are highly regular, as indicated by the tidal current time series that resembles a sinusoidal function. This study also shows that the theoretical force and power densities derived from the current measurements can significantly be influenced by the length of the time window used for averaging the current data. Furthermore, the theoretical power density at the site, derived from the current measurements, is one order of magnitude greater than that reported in the U.S. national resource assessment. As a result, this discrepancy highlights the importance of conducting site resource assessments based on measurements at the tidal energy converter device scale.« less

  7. TIDAL TURBULENCE SPECTRA FROM A COMPLIANT MOORING

    SciTech Connect

    Thomson, Jim; Kilcher, Levi; Richmond, Marshall C.; Talbert, Joe; deKlerk, Alex; Polagye, Brian; Guerra, Maricarmen; Cienfuegos, Rodrigo

    2013-06-13

    A compliant mooring to collect high frequency turbulence data at a tidal energy site is evaluated in a series of short demon- stration deployments. The Tidal Turbulence Mooring (TTM) improves upon recent bottom-mounted approaches by suspend- ing Acoustic Doppler Velocimeters (ADVs) at mid-water depths (which are more relevant to tidal turbines). The ADV turbulence data are superior to Acoustic Doppler Current Profiler (ADCP) data, but are subject to motion contamination when suspended on a mooring in strong currents. In this demonstration, passive stabilization is shown to be sufficient for acquiring bulk statistics of the turbulence, without motion correction. With motion cor- rection (post-processing), data quality is further improved; the relative merits of direct and spectral motion correction are dis- cussed.

  8. Surface acoustic wave amplification by direct current-voltage supplied to graphene film

    SciTech Connect

    Insepov, Z.; Emelin, E.; Kononenko, O.; Roshchupkin, D. V.; Tnyshtykbayev, K. B.; Baigarin, K. A.

    2015-01-12

    Using a high-resolution X-Ray diffraction measurement method, the surface acoustic wave (SAW) propagation in a graphene film on the surface of a Ca{sub 3}TaGa{sub 3}Si{sub 2}O{sub 14} (CTGS) piezoelectric crystal was investigated, where an external current was driven across the graphene film. Here, we show that the application of the DC field leads to a significant enhancement of the SAW magnitude and, as a result, to amplification of the diffraction satellites. Amplification of 33.2 dB/cm for the satellite +1, and of 13.8 dB/cm for the satellite +2, at 471 MHz has been observed where the external DC voltage of +10 V was applied. Amplification of SAW occurs above a DC field much smaller than that of a system using bulk semiconductor. Theoretical estimates are in reasonable agreement with our measurements and analysis of experimental data for other materials.

  9. MHK Projects/Tidal Energy Device Evaluation Center TIDEC | Open...

    OpenEI (Open Energy Information) [EERE & EIA]

    StateProvince Maine Project Country United States Project Resource Click here Current Tidal Coordinates 44.3879, -68.7998 Project Phase Phase 1 Device Nameplate Capacity (MW)...

  10. MHK Projects/Lubec Narrows Tidal | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Resource Click here Current Tidal Project Nearest Body of Water Lubec Narrows and Johnson Bay Coordinates 44.8652, -66.9828 Project Phase Phase 1 PermitLicense Buildout...

  11. MHK Technologies/Sabella subsea tidal turbine | Open Energy Informatio...

    OpenEI (Open Energy Information) [EERE & EIA]

    surface. These turbines are stabilised by gravity andor are anchored according to the nature of the seafloor. They are pre-orientated in the direction of the tidal currents, and...

  12. MHK Technologies/MORILD 2 Floating Tidal Power System | Open...

    OpenEI (Open Energy Information) [EERE & EIA]

    based on the same principle as horizontal axis wind turbines. The plant has 4 two-blade underwater turbines and can utilize the energy potential in tidal and ocean currents....

  13. MHK Projects/Central Cook Inlet Tidal Energy Project | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Province Alaska Project Country United States Project Resource Click here Current Tidal Coordinates 59.9669, -152.226 Project Phase Phase 1 Main Overseeing Organization...

  14. MHK Projects/Half Moon Cove Tidal Project | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Country United States Project Resource Click here Current Tidal Project Nearest Body of Water Passamaquoddy Bay Coordinates 44.9062, -66.99 Project Phase Phase 1 Project...

  15. Microsoft Word - RM1_Tidal Turbine_NREL Lawson, Li Y, Sale_2011...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    The Netherlands OMAE2011-49863 DEVELOPMENT AND VERIFICATION OF A COMPUTATIONAL FLUID DYNAMICS MODEL OF A HORIZONTAL-AXIS TIDAL CURRENT TURBINE ABSTRACT This paper describes the ...

  16. Tidal & Current Modeling Development and Validation

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    and Application Center for Hydrogen Energy Research Programs ARPA-E Basic Energy Sciences ... Sea State Contour) Code Online Abstracts and Reports Water Power Personnel ...

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

    SciTech Connect

    Nobukawa, Hisashi; Kitamura, Mitsuru; Swilem, S.A.M.; Ishibashi, Kozo

    1994-12-31

    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.

  18. Tidal Energy Research

    SciTech Connect

    Stelzenmuller, Nickolas; Aliseda, Alberto; Palodichuk, Michael; Polagye, Brian; Thomson, James; Chime, Arshiya; Malte, Philip

    2014-03-31

    This technical report contains results on the following topics: 1) Testing and analysis of sub-scale hydro-kinetic turbines in a flume, including the design and fabrication of the instrumented turbines. 2) Field measurements and analysis of the tidal energy resource and at a site in northern Puget Sound, that is being examined for turbine installation. 3) Conceptual design and performance analysis of hydro-kinetic turbines operating at high blockage ratio, for use for power generation and flow control in open channel flows.

  19. TidalStream | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    TidalStream Jump to: navigation, search Name: TidalStream Place: Southam, United Kingdom Zip: CV47 0HF Product: UK-based developer of platforms for tidal turbines. Coordinates:...

  20. Alternating current photovoltaic building block - Energy Innovation Portal

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    1103 Site Map Printable Version Share this resource About Search Categories (15) Advanced Materials Biomass and Biofuels Building Energy Efficiency Electricity Transmission Energy Analysis Energy Storage Geothermal Hydrogen and Fuel Cell Hydropower, Wave and Tidal Industrial Technologies Solar Photovoltaic Solar Thermal Startup America Vehicles and Fuels Wind Energy Partners (27) Visual Patent Search Success Stories Return to Search Alternating current photovoltaic building block United States

  1. Aternating current photovoltaic building block - Energy Innovation Portal

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    0,391 Site Map Printable Version Share this resource About Search Categories (15) Advanced Materials Biomass and Biofuels Building Energy Efficiency Electricity Transmission Energy Analysis Energy Storage Geothermal Hydrogen and Fuel Cell Hydropower, Wave and Tidal Industrial Technologies Solar Photovoltaic Solar Thermal Startup America Vehicles and Fuels Wind Energy Partners (27) Visual Patent Search Success Stories Find More Like This Return to Search Aternating current photovoltaic building

  2. Tidal Energy Limited | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Limited Jump to: navigation, search Name: Tidal Energy Limited (TEL) Place: Cardiff, Wales, United Kingdom Zip: CF23 8RS Product: Tidal stream device developer. Coordinates:...

  3. Tocardo Tidal Energy Ltd | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Tocardo Tidal Energy Ltd Jump to: navigation, search Name: Tocardo Tidal Energy Ltd Address: De Weel 20 Place: Zijdewind Zip: 1736KB Region: Netherlands Sector: Marine and...

  4. Making Wave Power Efficient and Affordable | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    ARPA-E Technology Showcase: Project Spotlight Energy Department Awards 7.4 Million to Develop Advanced Components for Wave and Tidal Energy Systems Project Overview Positive ...

  5. Advancing Technology Readiness: Wave Energy Testing and Demonstration...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    EERE is leading the effort to prove functionality, evaluate technical and economic viability, and generate cost, performance, and reliability data for a variety of wave, tidal, and ...

  6. List of Wave Energy Incentives | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Coal with CCS Concentrating Solar Power Energy Storage Fuel Cells Geothermal Electric Natural Gas Nuclear Tidal Energy Wave Energy Wind energy BiomassBiogas Hydroelectric...

  7. NATIONAL GEODATABASE OF TIDAL STREAM POWER RESOURCE IN USA

    SciTech Connect

    Smith, Brennan T; Neary, Vincent S; Stewart, Kevin M

    2012-01-01

    A geodatabase of tidal constituents is developed to present the regional assessment of tidal stream power resource in the USA. Tidal currents are numerically modeled with the Regional Ocean Modeling System (ROMS) and calibrated with the available measurements of tidal current speeds and water level surfaces. The performance of the numerical model in predicting the tidal currents and water levels is assessed by an independent validation. The geodatabase is published on a public domain via a spatial database engine with interactive tools to select, query and download the data. Regions with the maximum average kinetic power density exceeding 500 W/m2 (corresponding to a current speed of ~1 m/s), total surface area larger than 0.5 km2 and depth greater than 5 m are defined as hotspots and documented. The regional assessment indicates that the state of Alaska (AK) has the largest number of locations with considerably high kinetic power density, followed by, Maine (ME), Washington (WA), Oregon (OR), California (CA), New Hampshire (NH), Massachusetts (MA), New York (NY), New Jersey (NJ), North and South Carolina (NC, SC), Georgia (GA), and Florida (FL).

  8. Ecological safety of tidal-power projects

    SciTech Connect

    Fedorov, M. P.; Shilin, M. B.

    2010-07-15

    The operating regime of tidal power plants requires ecological monitoring of their associated water area.

  9. Tidal Stream | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Stream Jump to: navigation, search Name: Tidal Stream Address: 76 Dukes Ave Place: London Zip: W4 2 AK Region: United Kingdom Sector: Marine and Hydrokinetic Phone Number: 01926...

  10. Tidal evolution of the spin-orbit angle in exoplanetary systems

    SciTech Connect

    Xue, Yuxin; Suto, Yasushi; Taruya, Atsushi; Hirano, Teruyuki; Fujii, Yuka; Masuda, Kento

    2014-03-20

    The angle between the stellar spin and the planetary orbit axes (the spin-orbit angle) is supposed to carry valuable information concerning the initial condition of planetary formation and subsequent migration history. Indeed, current observations of the Rossiter-McLaughlin effect have revealed a wide range of spin-orbit misalignments for transiting exoplanets. We examine in detail the tidal evolution of a simple system comprising a Sun-like star and a hot Jupiter adopting the equilibrium tide and the inertial wave dissipation effects simultaneously. We find that the combined tidal model works as a very efficient realignment mechanism; it predicts three distinct states of the spin-orbit angle (i.e., parallel, polar, and antiparallel orbits) for a while, but the latter two states eventually approach the parallel spin-orbit configuration. The intermediate spin-orbit angles as measured in recent observations are difficult to obtain. Therefore the current model cannot reproduce the observed broad distribution of the spin-orbit angles, at least in its simple form. This indicates that the observed diversity of the spin-orbit angles may emerge from more complicated interactions with outer planets and/or may be the consequence of the primordial misalignment between the protoplanetary disk and the stellar spin, which requires future detailed studies.

  11. A 200-A, 500-Hz, triangle current-wave modulator and magnet used for particle beam rastering

    SciTech Connect

    Rose, C.R.; Shafer, R.E.

    1997-10-01

    This paper describes a simple 2D beam-rastering system to uniformly spread a 100-mA 6.7-MeV cw proton beam over a 50-cm by 50-cm beam stop. The basic circuit uses a 20-mF capacitor bank, a IGBT (insulated gate bipolar transistor) full-wave inverter, and a 1-mH ferrite dipole magnet to produce a {+-} 500-Gauss peak triangular-waveform deflection field at 500 Hz. A dc input voltage of 200 volts at 2.6 amps (520 watts) produces a 160-ampere peak-to-peak triangular current waveform in the ferrite magnet at 500 Hz. For dual-axis rastering, two ferrite dipoles are used, one at 500 Hz, and the other at 575 Hz, to produce a uniform 2D beam distribution at the beam stop. The paper will discuss the IGBT modulator and ferrite deflector in detail, including current and voltage waveforms, and the ferrite magnet B-dot (dB/dt) signal.

  12. Category:Earth Tidal Analysis | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Earth Tidal Analysis Jump to: navigation, search Geothermalpower.jpg Looking for the Earth Tidal Analysis page? For detailed information on Earth Tidal Analysis, click here....

  13. MHK Technologies/Deep Gen Tidal Turbines | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Gen Tidal Turbines < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Deep Gen Tidal Turbines.jpg Technology Profile Primary Organization Tidal...

  14. Microsoft Word - RM1_Tidal Turbine_UW Tidal Resource-Abstract...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    turbine operating in a narrow, tidal channel. The site is a generalized version of Tacoma Narrows, Puget Sound, Washington. The resource is a mixed, mainly semidiurnal tidal...

  15. Tidal Generation Ltd | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Generation Ltd EMEC This company is involved in the following MHK Technologies: Deep Gen Tidal Turbines This article is a stub. You can help OpenEI by expanding it. Tidal...

  16. Experimental Wave Tank Test for Reference Model 3 Floating-Point Absorber Wave Energy Converter Project

    SciTech Connect

    Yu, Y. H.; Lawson, M.; Li, Y.; Previsic, M.; Epler, J.; Lou, J.

    2015-01-01

    The U.S. Department of Energy established a reference model project to benchmark a set of marine and hydrokinetic technologies including current (tidal, open-ocean, and river) turbines and wave energy converters. The objectives of the project were to first evaluate the status of these technologies and their readiness for commercial applications. Second, to evaluate the potential cost of energy and identify cost-reduction pathways and areas where additional research could be best applied to accelerate technology development to market readiness.

  17. ENHANCED OFF-CENTER STELLAR TIDAL DISRUPTIONS BY SUPERMASSIVE BLACK HOLES IN MERGING GALAXIES

    SciTech Connect

    Liu, F. K.; Chen, Xian E-mail: chenxian@pku.edu.cn

    2013-04-10

    Off-center stellar tidal disruption flares have been suggested to be a powerful probe of recoiling supermassive black holes (SMBHs) out of galactic centers due to anisotropic gravitational wave radiations. However, off-center tidal flares can also be produced by SMBHs in merging galaxies. In this paper, we computed the tidal flare rates by dual SMBHs in two merging galaxies before the SMBHs become self-gravitationally bounded. We employ an analytical model to calculate the tidal loss-cone feeding rates for both SMBHs, taking into account two-body relaxation of stars, tidal perturbations by the companion galaxy, and chaotic stellar orbits in triaxial gravitational potential. We show that for typical SMBHs with masses 10{sup 7} M{sub Sun }, the loss-cone feeding rates are enhanced by mergers up to {Gamma} {approx} 10{sup -2} yr{sup -1}, about two orders of magnitude higher than those by single SMBHs in isolated galaxies and about four orders of magnitude higher than those by recoiling SMBHs. The enhancements are mainly due to tidal perturbations by the companion galaxy. We suggest that off-center tidal flares are overwhelmed by those from merging galaxies, making the identification of recoiling SMBHs challenging. Based on the calculated rates, we estimate the relative contributions of tidal flare events by single, binary, and dual SMBH systems during cosmic time. Our calculations show that the off-center tidal disruption flares by un-bound SMBHs in merging galaxies contribute a fraction comparable to that by single SMBHs in isolated galaxies. We conclude that off-center tidal disruptions are powerful tracers of the merging history of galaxies and SMBHs.

  18. Ocean current resource assessment | Department of Energy

    Energy.gov [DOE] (indexed site)

    Tidal Energy Resource Assessment Free Flow Energy (TRL 1 2 3 Component) - Design and Development of a Cross-Platform Submersible Generator Optimized for the Conditions of Current ...

  19. Natural Currents Energy Services | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Wiscasset Tidal Energy Plant This company is involved in the following MHK Technologies: RED HAWK Retrieved from "http:en.openei.orgwindex.php?titleNaturalCurrentsEnergySer...

  20. Current generation by helicons and LH waves in modern tokamaks and reactors FNSF-AT, ITER and DEMO. Scenarios, modeling and antennae

    SciTech Connect

    Vdovin, V.

    2014-02-12

    The Innovative concept and 3D full wave code modeling Off-axis current drive by RF waves in large scale tokamaks, reactors FNSF-AT, ITER and DEMO for steady state operation with high efficiency was proposed [1] to overcome problems well known for LH method [2]. The scheme uses the helicons radiation (fast magnetosonic waves at high (20–40) IC frequency harmonics) at frequencies of 500–1000 MHz, propagating in the outer regions of the plasmas with a rotational transform. It is expected that the current generated by Helicons will help to have regimes with negative magnetic shear and internal transport barrier to ensure stability at high normalized plasma pressure β{sub N} > 3 (the so-called Advanced scenarios) of interest for FNSF and the commercial reactor. Modeling with full wave three-dimensional codes PSTELION and STELEC2 showed flexible control of the current profile in the reactor plasmas of ITER, FNSF-AT and DEMO [2,3], using multiple frequencies, the positions of the antennae and toroidal waves slow down. Also presented are the results of simulations of current generation by helicons in tokamaks DIII-D, T-15MD and JT-60SA [3]. In DEMO and Power Plant antenna is strongly simplified, being some analoge of mirrors based ECRF launcher, as will be shown. For spherical tokamaks the Helicons excitation scheme does not provide efficient Off-axis CD profile flexibility due to strong coupling of helicons with O-mode, also through the boundary conditions in low aspect machines, and intrinsic large amount of trapped electrons, as is shown by STELION modeling for the NSTX tokamak. Brief history of Helicons experimental and modeling exploration in straight plasmas, tokamaks and tokamak based fusion Reactors projects is given, including planned joint DIII-D – Kurchatov Institute experiment on helicons CD [1].

  1. MHK ISDB/Instruments/ACM-WAVE-PLUS | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Velocity Planar Measurement (Current), 3D Velocity Volumetric Measurement (Current), Density (Ice), Direction (Ice), Speed (Ice), Thickness (Ice), Pressure (Tidal), Sea Surface...

  2. MHK ISDB/Sensors/Vented Wave Sensor | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Velocity Planar Measurement (Current), 3D Velocity Volumetric Measurement (Current), Density (Ice), Direction (Ice), Speed (Ice), Thickness (Ice), Pressure (Tidal), Sea Surface...

  3. Maine Tidal Power Initiative: Environmental Impact Protocols For Tidal Power

    SciTech Connect

    Peterson, Michael Leroy; Zydlewski, Gayle Barbin; Xue, Huijie; Johnson, Teresa R.

    2014-02-02

    The Maine Tidal Power Initiative (MTPI), an interdisciplinary group of engineers, biologists, oceanographers, and social scientists, has been conducting research to evaluate tidal energy resources and better understand the potential effects and impacts of marine hydro-kinetic (MHK) development on the environment and local community. Project efforts include: 1) resource assessment, 2) development of initial device design parameters using scale model tests, 3) baseline environmental studies and monitoring, and 4) human and community responses. This work included in-situ measurement of the environmental and social response to the pre-commercial Turbine Generator Unit (TGU®) developed by Ocean Renewable Power Company (ORPC) as well as considering the path forward for smaller community scale projects.

  4. MHK Technologies/Current Catcher | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Primary Organization Offshore Islands Ltd Technology Resource Click here CurrentTidal Technology Type Click here Axial Flow Turbine Technology Description The Current...

  5. MHK ISDB/Instruments/Nortek Aquadopp Current Meter | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Velocity Planar Measurement (Current), 3D Velocity Volumetric Measurement (Current), Density (Ice), Direction (Ice), Speed (Ice), Thickness (Ice), Pressure (Tidal), Sea Surface...

  6. Tidal Residual Eddies and their Effect on Water Exchange in Puget Sound

    SciTech Connect

    Yang, Zhaoqing; Wang, Taiping

    2013-08-30

    Tidal residual eddies are one of the important hydrodynamic features in tidally dominant estuaries and coastal bays, and they could have significant effects on water exchange in a tidal system. This paper presents a modeling study of tides and tidal residual eddies in Puget Sound, a tidally dominant fjord-like estuary in the Pacific Northwest coast, using a three-dimensional finite-volume coastal ocean model. Mechanisms of vorticity generation and asymmetric distribution patterns around an island/headland were analyzed using the dynamic vorticity transfer approach and numerical experiments. Model results of Puget Sound show that a number of large twin tidal residual eddies exist in the Admiralty Inlet because of the presence of major headlands in the inlet. Simulated residual vorticities near the major headlands indicate that the clockwise tidal residual eddy (negative vorticity) is generally stronger than the anticlockwise eddy (positive vorticity) because of the effect of Coriolis force. The effect of tidal residual eddies on water exchange in Puget Sound and its sub-basins were evaluated by simulations of dye transport. It was found that the strong transverse variability of residual currents in the Admiralty Inlet results in a dominant seaward transport along the eastern shore and a dominant landward transport along the western shore of the Inlet. A similar transport pattern in Hood Canal is caused by the presence of tidal residual eddies near the entrance of the canal. Model results show that tidal residual currents in Whidbey Basin are small in comparison to other sub-basins. A large clockwise residual circulation is formed around Vashon Island near entrance of South Sound, which can potentially constrain the water exchange between the Central Basin and South Sound.

  7. Tidally-Induced Thermonuclear Supernovae

    SciTech Connect

    Rosswog, S.; Ramirez-Ruiz, E.; Hix, William Raphael

    2009-01-01

    We discuss the results of 3D simulations of tidal disruptions of white dwarfs by moderate-mass black holes as they may exist in the cores of globular clusters or dwarf galaxies. Our simulations follow self-consistently the hydrodynamic and nuclear evolution from the initial parabolic orbit over the disruption to the build-up of an accretion disk around the black hole. For strong enough encounters (pericentre distances smaller than about 1/3 of the tidal radius) the tidal compression is reversed by a shock and finally results in a thermonuclear explosion. These explosions are not restricted to progenitor masses close to the Chandrasekhar limit, we find exploding examples throughout the whole white dwarf mass range. There is, however, a restriction on the masses of the involved black holes: black holes more massive than 2x105M{circle_dot} swallow a typical 0.6M{circle_dot} white dwarf before their tidal forces can overwhelm the star's selfgravity. Therefore, this mechanism is characteristic for black holes of moderate masses. The material that remains bound to the black hole settles into an accretion disk and produces an Xray flare close to the Eddington limit of L{sub Edd} {approx} 10{sup 41}erg/s (Mbh/1000M{circle_dot}), typically lasting for a few months. The combination of a peculiar thermonuclear supernova together with an X-ray flare thus whistle-blows the existence of such moderate-mass black holes. The next generation of wide field space-based instruments should be able to detect such events.

  8. ARRAY OPTIMIZATION FOR TIDAL ENERGY EXTRACTION IN A TIDAL CHANNEL A NUMERICAL MODELING ANALYSIS

    SciTech Connect

    Yang, Zhaoqing; Wang, Taiping; Copping, Andrea

    2014-04-18

    This paper presents an application of a hydrodynamic model to simulate tidal energy extraction in a tidal dominated estuary in the Pacific Northwest coast. A series of numerical experiments were carried out to simulate tidal energy extraction with different turbine array configurations, including location, spacing and array size. Preliminary model results suggest that array optimization for tidal energy extraction in a real-world site is a very complex process that requires consideration of multiple factors. Numerical models can be used effectively to assist turbine siting and array arrangement in a tidal turbine farm for tidal energy extraction.

  9. Tidal Sails AS | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Sails AS Jump to: navigation, search Name: Tidal Sails AS Address: Standgaten 130 Place: Haugesund Zip: 5531 Region: Norway Sector: Marine and Hydrokinetic Phone Number: +32 474 98...

  10. Tidal Hydraulic Generators Ltd | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Hydraulic Generators Ltd Jump to: navigation, search Name: Tidal Hydraulic Generators Ltd Address: 14 Thislesboon Drive Place: Mumbles Zip: SA3 4HY Region: United Kingdom Sector:...

  11. Pennamaquan Tidal Power LLC | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    LLC Jump to: navigation, search Name: Pennamaquan Tidal Power LLC Address: 45 Memorial Circle PO Box 1058 Place: Augusta Zip: 4332 Region: United States Sector: Marine and...

  12. Acoustic Effects of Hydrokinetic Tidal Turbines

    SciTech Connect

    Polagye, Brian

    2011-11-01

    This presentation from the Water Peer Review highlights one of the program's marine and hyrokinetics environmental projects to determine the likely acoustic effects from a tidal energy device.

  13. Earth Tidal Analysis | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    of earth tide response of three deep, confined aquifers Earth Tidal Analysis At Raft River Geothermal Area (1980) Raft River Geothermal Area 1980 1980 Reservoir response to...

  14. Tidal Energy Basics | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Renewable Energy » Ocean » Tidal Energy Basics Tidal Energy Basics August 16, 2013 - 4:26pm Addthis Photo of the ocean rising along the beach. Some of the oldest ocean energy technologies use tidal power. All coastal areas experience two high tides and two low tides over a period of slightly more than 24 hours. For those tidal differences to be harnessed into electricity, the difference between high and low tides must be more than 16 feet (or at least 5 meters). However, there are only about

  15. Tidal Energy Test Platform | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Test Platform Jump to: navigation, search Basic Specifications Facility Name Tidal Energy Test Platform Overseeing Organization University of New Hampshire Hydrodynamics...

  16. First Commercial, Grid-Connected, Hydrokinetic Tidal Energy Project...

    Office of Science (SC)

    ORPC's TidGen(tm) turbine generator unit. R&D Opportunity Advanced water power technologies include devices capable of extracting electrical power from waves, water currents, and ...

  17. Effects of the radial dependence of the fast electron diffusion coefficient on the current driven by lower-hybrid waves in tokamak

    SciTech Connect

    Zhang Xianmei; Wang Yanhui; Yu Limin; Shen Xin; Wang Jianbin

    2012-07-15

    The lower hybrid current drive (LHCD) is one of the promising methods not only for driving the non-inductive current required for steady-state tokamak operation, but also for controlling the plasma current profile to improve confinement in tokamak experiments. A direct consequence of experimental imperfection is difficult to obtain reliable estimate of the radial diffusion coefficient (D{sub st}) of the lower hybrid driven current. In this paper, the radial profile of D{sub st} is estimated to investigate its effect on the current driven by lower hybrid wave (LHW) in Experimental Advanced Superconducting Tokamak. Compared with the case of the constant radial diffusion coefficient, the efficiency of LHW driven current with the radial dependent diffusion coefficient D{sub st} ({rho}) becomes either higher or lower with respect to the plasma parameters, such as the density and the magnetic fluctuation. It is also found that the profiles of the LHW driven current are different. Therefore, it is necessary to consider the radial dependence of D{sub st} in order to get an accurate and reliable result in the numerical simulation of LHCD.

  18. Wave Energy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Wave Energy Jump to: navigation, search Contents 1 Description 2 History 3 Technology 4 Current and Possible Wave Farms 5 Pros and Cons Description Wave energy (or wave power) is...

  19. Hydra Tidal Energy Technology AS | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Tidal Energy Technology AS Jump to: navigation, search Name: Hydra Tidal Energy Technology AS Address: PO Box 399 Place: Harstad Zip: 9484 Region: Norway Sector: Marine and...

  20. Verdant-Roosevelt Island Tidal Energy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Verdant-Roosevelt Island Tidal Energy Jump to: navigation, search Retrieved from "http:en.openei.orgwindex.php?titleVerdant-RooseveltIslandTidalEnergy&oldid680702" ...

  1. MHK Technologies/Sihwa tidal barrage power plant | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Sihwa tidal barrage power plant < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Sihwa tidal barrage power plant.jpg Technology Profile...

  2. MHK Technologies/Tidal Delay | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Tidal Delay < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Tidal Delay.png Technology Profile Primary Organization Woodshed Technologies Ltd...

  3. Severn Tidal Power Group STpg | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Severn Tidal Power Group STpg Jump to: navigation, search Name: Severn Tidal Power Group STpg Region: United Kingdom Sector: Marine and Hydrokinetic Website: http: This company is...

  4. MHK Technologies/Jiangxia Tidal Power Station | Open Energy Informatio...

    OpenEI (Open Energy Information) [EERE & EIA]

    Jiangxia Tidal Power Station < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Jiangxia Tidal Power Station.jpg Technology Profile Primary...

  5. High Fidelity Evaluation of Tidal Turbine Performance for Industry...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Fidelity Evaluation of Tidal Turbine Performance for Industry Partner - Sandia Energy ... High Fidelity Evaluation of Tidal Turbine Performance for Industry Partner Home...

  6. MHK Technologies/Scotrenewables Tidal Turbine SRTT | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Tidal Turbine SRTT < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Scotrenewables Tidal Turbine SRTT.jpg Technology Profile Primary...

  7. MHK Technologies/Rotech Tidal Turbine RTT | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Rotech Tidal Turbine RTT < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Rotech Tidal Turbine RTT.jpg Technology Profile Primary Organization...

  8. MHK Projects/Tidal Generation Ltd EMEC | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Overseeing Organization Tidal Generation Ltd Project Technology *MHK TechnologiesDeep Gen Tidal Turbines Project Licensing Environmental Monitoring and Mitigation Efforts See...

  9. The Wash Tidal Barrier Corporation | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Jump to: navigation, search Name: The Wash Tidal Barrier Corporation Place: Cambridge, England, United Kingdom Zip: CB24 8RX Product: Company building a tidal barrier...

  10. Tidal dissipation in a homogeneous spherical body. I. Methods

    SciTech Connect

    Efroimsky, Michael; Makarov, Valeri V. E-mail: vvm@usno.navy.mil

    2014-11-01

    A formula for the tidal dissipation rate in a spherical body is derived from first principles to correct some mathematical inaccuracies found in the literature. The development is combined with the Darwin-Kaula formalism for tides. Our intermediate results are compared with those by Zschau and Platzman. When restricted to the special case of an incompressible spherical planet spinning synchronously without libration, our final formula can be compared with the commonly used expression from Peale and Cassen. However, the two turn out to differ, as in our expression the contributions from all Fourier modes are positive-definite, which is not the case with the formula from Peale and Cassen. Examples of the application of our expression for the tidal damping rate are provided in the work by Makarov and Efroimsky (Paper II) published back to back with the current paper.

  11. Feasibility of Tital and Ocean Current Energy in False Pass,...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    - Alaska Feasibility of Tidal and Ocean Current Energy in False Pass, Aleutian Islands, ... to seven sites to assess hazards to successful ADCP deployment and retrieval. ...

  12. Measurements of Turbulence at Two Tidal Energy Sites in Puget Sound, WA

    SciTech Connect

    Thomson, Jim; Polagye, Brian; Durgesh, Vibhav; Richmond, Marshall C.

    2012-06-05

    Field measurements of turbulence are pre- sented from two sites in Puget Sound, WA (USA) that are proposed for electrical power generation using tidal current turbines. Rapidly sampled data from multiple acoustic Doppler instruments are analyzed to obtain statistical mea- sures of fluctuations in both the magnitude and direction of the tidal currents. The resulting turbulence intensities (i.e., the turbulent velocity fluctuations normalized by the harmonic tidal currents) are typically 10% at the hub- heights (i.e., the relevant depth bin) of the proposed turbines. Length and time scales of the turbulence are also analyzed. Large-scale, anisotropic eddies dominate the energy spectra, which may be the result of proximity to headlands at each site. At small scales, an isotropic turbulent cascade is observed and used to estimate the dissipation rate of turbulent kinetic energy. Data quality and sampling parameters are discussed, with an emphasis on the removal of Doppler noise from turbulence statistics.

  13. Microsoft Word - RM1_Tidal Turbine_UW Tidal Resource-Abstract...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Brian Polagye Northwest National Marine Renewable Energy Center University of Washington, Seattle, WA Introduction Reference Model 1 is a tidal turbine operating in a narrow, ...

  14. Half Moon Cove Tidal Project. Feasibility report

    SciTech Connect

    Not Available

    1980-11-01

    The proposed Half Moon Cove Tidal Power Project would be located in a small cove in the northern part of Cobscook Bay in the vicinity of Eastport, Maine. The project would be the first tidal electric power generating plant in the United States of America. The basin impounded by the barrier when full will approximate 1.2 square miles. The average tidal range at Eastport is 18.2 feet. The maximum spring tidal range will be 26.2 feet and the neap tidal range 12.8 feet. The project will be of the single pool-type single effect in which generation takes place on the ebb tide only. Utilizing an average mean tidal range of 18.2 feet the mode of operation enables generation for approximately ten and one-half (10-1/2) hours per day or slightly in excess of five (5) hours per tide. The installed capacity will be 12 MW utilizing 2 to 6 MW units. An axial flow, or Bulb type of turbine was selected for this study.

  15. About Cost Breakdown Structure for Tidal Current Device Created...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    ... 1.5.10 Bearings and Linear Guides 5.1533786848072562 1.3723654285407809 ... Environmental Monitoring and Regulatory Compliance 24.567754110451993 ...

  16. OPTICAL TRANSIENTS FROM THE UNBOUND DEBRIS OF TIDAL DISRUPTION

    SciTech Connect

    Kasen, Daniel; Ramirez-Ruiz, Enrico

    2010-05-01

    In the tidal disruption of a star by a black hole, roughly half of the stellar mass becomes bound and falls into the black hole, while the other half is ejected at high velocity. Several previous studies have considered the emission resulting from the accretion of bound material; we consider the possibility that the unbound debris may also radiate once it has expanded and become transparent. We show that the gradual energy input from hydrogen recombination compensates for adiabatic losses over significant expansion factors. The opacity also drops dramatically with recombination, and the internal energy can be radiated by means of a cooling-transparency wave propagating from the surface layers inward. The result is a brief optical transient occurring {approx} 1 week after disruption and lasting 3-5 days with peak luminosities of 10{sup 40}-10{sup 42} ergs s{sup -1}, depending on the mass of the disrupted star. These recombination powered transients should accompany the X-ray/ultraviolet flare from the accretion of bound material, and so may be a useful signature for discriminating tidal disruption events, especially for lower and intermediate mass black holes.

  17. Dispersion mechanisms of a tidal river junction in the Sacramento–San Joaquin Delta, California

    SciTech Connect

    Gleichauf, Karla T.; Wolfram, Philip J.; Monsen, Nancy E.; Fringer, Oliver B.; Monismith, Stephen G.

    2014-12-17

    In branching channel networks, such as in the Sacramento–San Joaquin River Delta, junction flow dynamics contribute to dispersion of ecologically important entities such as fish, pollutants, nutrients, salt, sediment, and phytoplankton. Flow transport through a junction largely arises from velocity phasing in the form of divergent flow between junction channels for a portion of the tidal cycle. Field observations in the Georgiana Slough junction, which is composed of the North and South Mokelumne rivers, Georgiana Slough, and the Mokelumne River, show that flow phasing differences between these rivers arise from operational, riverine, and tidal forcing. A combination of Acoustic Doppler Current Profile (ADCP) boat transecting and moored ADCPs over a spring–neap tidal cycle (May to June 2012) monitored the variability of spatial and temporal velocity, respectively. Two complementary drifter studies enabled assessment of local transport through the junction to identify small-scale intrajunction dynamics. We supplemented field results with numerical simulations using the SUNTANS model to demonstrate the importance of phasing offsets for junction transport and dispersion. Different phasing of inflows to the junction resulted in scalar patchiness that is characteristic of MacVean and Stacey’s (2011) advective tidal trapping. Furthermore, we observed small-scale junction flow features including a recirculation zone and shear layer, which play an important role in intra-junction mixing over time scales shorter than the tidal cycle (i.e., super-tidal time scales). Thus, the study period spanned open- and closed-gate operations at the Delta Cross Channel. Synthesis of field observations and modeling efforts suggest that management operations related to the Delta Cross Channel can strongly affect transport in the Delta by modifying the relative contributions of tidal and riverine flows, thereby changing the junction flow phasing.

  18. Dispersion mechanisms of a tidal river junction in the Sacramento–San Joaquin Delta, California

    DOE PAGES [OSTI]

    Gleichauf, Karla T.; Wolfram, Philip J.; Monsen, Nancy E.; Fringer, Oliver B.; Monismith, Stephen G.

    2014-12-17

    In branching channel networks, such as in the Sacramento–San Joaquin River Delta, junction flow dynamics contribute to dispersion of ecologically important entities such as fish, pollutants, nutrients, salt, sediment, and phytoplankton. Flow transport through a junction largely arises from velocity phasing in the form of divergent flow between junction channels for a portion of the tidal cycle. Field observations in the Georgiana Slough junction, which is composed of the North and South Mokelumne rivers, Georgiana Slough, and the Mokelumne River, show that flow phasing differences between these rivers arise from operational, riverine, and tidal forcing. A combination of Acoustic Dopplermore » Current Profile (ADCP) boat transecting and moored ADCPs over a spring–neap tidal cycle (May to June 2012) monitored the variability of spatial and temporal velocity, respectively. Two complementary drifter studies enabled assessment of local transport through the junction to identify small-scale intrajunction dynamics. We supplemented field results with numerical simulations using the SUNTANS model to demonstrate the importance of phasing offsets for junction transport and dispersion. Different phasing of inflows to the junction resulted in scalar patchiness that is characteristic of MacVean and Stacey’s (2011) advective tidal trapping. Furthermore, we observed small-scale junction flow features including a recirculation zone and shear layer, which play an important role in intra-junction mixing over time scales shorter than the tidal cycle (i.e., super-tidal time scales). Thus, the study period spanned open- and closed-gate operations at the Delta Cross Channel. Synthesis of field observations and modeling efforts suggest that management operations related to the Delta Cross Channel can strongly affect transport in the Delta by modifying the relative contributions of tidal and riverine flows, thereby changing the junction flow phasing.« less

  19. MHK Technologies/Tidal Sails | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    to wires strung across the tidal stream at an angle The sails are driven back and forth by the tidal flow between two stations at one of which the generator is installed...

  20. Mapping the Potential of U.S. Ocean Energy | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    available in the nation's waves, tidal and river currents, and ocean thermal gradients. ... and global wave, tidal, ocean thermal, and continental U.S. river hydrokinetic resources. ...

  1. Tidal heating in multilayered terrestrial exoplanets

    SciTech Connect

    Henning, Wade G.; Hurford, Terry

    2014-07-01

    The internal pattern and overall magnitude of tidal heating for spin-synchronous terrestrial exoplanets from 1 to 2.5 R{sub E} is investigated using a propagator matrix method for a variety of layer structures. Particular attention is paid to ice-silicate hybrid super-Earths, where a significant ice mantle is modeled to rest atop an iron-silicate core, and may or may not contain a liquid water ocean. We find multilayer modeling often increases tidal dissipation relative to a homogeneous model, across multiple orbital periods, due to the ability to include smaller volume low viscosity regions, and the added flexure allowed by liquid layers. Gradations in parameters with depth are explored, such as allowed by the Preliminary Earth Reference Model. For ice-silicate hybrid worlds, dramatically greater dissipation is possible beyond the case of a silicate mantle only, allowing non-negligible tidal activity to extend to greater orbital periods than previously predicted. Surface patterns of tidal heating are found to potentially be useful for distinguishing internal structure. The influence of ice mantle depth and water ocean size and position are shown for a range of forcing frequencies. Rates of orbital circularization are found to be 10-100 times faster than standard predictions for Earth-analog planets when interiors are moderately warmer than the modern Earth, as well as for a diverse range of ice-silicate hybrid super-Earths. Circularization rates are shown to be significantly longer for planets with layers equivalent to an ocean-free modern Earth, as well as for planets with high fractions of either ice or silicate melting.

  2. Tidal constituent database. West Coast of the United States and Eastern North pacific ocean. Technical note

    SciTech Connect

    1995-01-01

    This technical note describes a database of tidal elevation boundary condition information generated in support of the `Long-Term Fate of Dredged Material Disposed in Open Water` research of the Dredging Research Program (DRP), being conducted at the U.S. Army Engineer Waterways Experiment Station. The database, described in detail by Hench and others (1994), allows the user to manually generate time series of tidal elevations or to use a program to access the full database to generate time series of both tidal elevations and currents for any location along the West Coast of the United States and Eastern North Pacific Ocean, extending from Seal Cape on Unimak Island, Alaska, in the North to Punta Parada, Peru, in the South. The land boundary includes the Pacific shorelines of Alaska, Canada, mainland United States, Mexico, Guatemala, El Salvador, Nicaragua, Costa Rica, Panama, Columbia, and Northern Peru. Although the capability to generate these time series was developed to provide input to the Long-Term Fate and Stability Model (LTFATE), the generated time series can be used for any application requiring tidal forcing data.

  3. Study of the Acoustic Effects of Hydrokinetic Tidal Turbines in Admiralty Inlet, Puget Sound

    SciTech Connect

    Brian Polagye; Jim Thomson; Chris Bassett; Jason Wood; Dom Tollit; Robert Cavagnaro; Andrea Copping

    2012-03-30

    Hydrokinetic turbines will be a source of noise in the marine environment - both during operation and during installation/removal. High intensity sound can cause injury or behavioral changes in marine mammals and may also affect fish and invertebrates. These noise effects are, however, highly dependent on the individual marine animals; the intensity, frequency, and duration of the sound; and context in which the sound is received. In other words, production of sound is a necessary, but not sufficient, condition for an environmental impact. At a workshop on the environmental effects of tidal energy development, experts identified sound produced by turbines as an area of potentially significant impact, but also high uncertainty. The overall objectives of this project are to improve our understanding of the potential acoustic effects of tidal turbines by: (1) Characterizing sources of existing underwater noise; (2) Assessing the effectiveness of monitoring technologies to characterize underwater noise and marine mammal responsiveness to noise; (3) Evaluating the sound profile of an operating tidal turbine; and (4) Studying the effect of turbine sound on surrogate species in a laboratory environment. This study focuses on a specific case study for tidal energy development in Admiralty Inlet, Puget Sound, Washington (USA), but the methodologies and results are applicable to other turbine technologies and geographic locations. The project succeeded in achieving the above objectives and, in doing so, substantially contributed to the body of knowledge around the acoustic effects of tidal energy development in several ways: (1) Through collection of data from Admiralty Inlet, established the sources of sound generated by strong currents (mobilizations of sediment and gravel) and determined that low-frequency sound recorded during periods of strong currents is non-propagating pseudo-sound. This helped to advance the debate within the marine and hydrokinetics acoustic

  4. MHK Projects/Astoria Tidal Energy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Astoria Tidal Energy < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type":"ROADMA...

  5. MHK Projects/Cape Islands Tidal Energy Project | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Islands Tidal Energy Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type"...

  6. MHK Projects/Town of Wiscasset Tidal Resources | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Town of Wiscasset Tidal Resources < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","...

  7. MHK Projects/Indian River Tidal Hydrokinetic Energy Project ...

    OpenEI (Open Energy Information) [EERE & EIA]

    Tidal Hydrokinetic Energy Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","...

  8. MHK Projects/Angoon Tidal Energy Plant | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Angoon Tidal Energy Plant < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type":"R...

  9. MHK Projects/Kendall Head Tidal Energy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Kendall Head Tidal Energy < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type":"R...

  10. MHK Projects/Kingsbridge Tidal Energy Project | Open Energy Informatio...

    OpenEI (Open Energy Information) [EERE & EIA]

    Kingsbridge Tidal Energy Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","t...

  11. MHK Projects/Roosevelt Island Tidal Energy RITE | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Roosevelt Island Tidal Energy RITE < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3",...

  12. MHK Projects/Kachemak Bay Tidal Energy Project | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Kachemak Bay Tidal Energy Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","...

  13. MHK Projects/Pennamaquan Tidal Power Plant | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Phase Phase ? PermitLicense Buildout (MW) 21 Main Overseeing Organization Pennamaquan Tidal Power LLC Project Licensing FERC License Docket Number P-13884 Environmental...

  14. MHK Projects/Central Cook Inlet Alaska Tidal Energy Project ...

    OpenEI (Open Energy Information) [EERE & EIA]

    Tidal Energy Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type":"ROADMA...

  15. MHK Projects/Portsmouth Area Tidal Energy Project | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Portsmouth Area Tidal Energy Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3...

  16. MHK Projects/Deception Pass Tidal Energy Hydroelectric Project...

    OpenEI (Open Energy Information) [EERE & EIA]

    Deception Pass Tidal Energy Hydroelectric Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice"...

  17. MHK Projects/Edgar Town Nantucket Tidal Energy | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Town Nantucket Tidal Energy < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type":...

  18. MHK Projects/Housatonic Tidal Energy Plant | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Housatonic Tidal Energy Plant < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type...

  19. MHK Projects/East Foreland Tidal Energy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    East Foreland Tidal Energy < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type":"...

  20. MHK Projects/Turnagain Arm Tidal | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Turnagain Arm Tidal < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP...

  1. MHK Projects/Cuttyhunk Tidal Energy Plant | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Cuttyhunk Tidal Energy Plant < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type"...

  2. MHK Projects/Spieden Channel Tidal Energy Project | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Spieden Channel Tidal Energy Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3...

  3. MHK Projects/Muskeget Channel Tidal Energy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Muskeget Channel Tidal Energy < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type...

  4. MHK Projects/Nantucket Tidal Energy Plant | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Nantucket Tidal Energy Plant < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type"...

  5. MHK Projects/Avalon Tidal | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Avalon Tidal < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP","zoom...

  6. MHK Projects/Piscataqua Tidal Hydrokinetic Energy Project | Open...

    OpenEI (Open Energy Information) [EERE & EIA]

    Piscataqua Tidal Hydrokinetic Energy Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"goo...

  7. MHK Projects/Highlands Tidal Energy Project | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Tidal Energy Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type":"ROADMA...

  8. MHK Projects/Penobscot Tidal Energy Project | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Penobscot Tidal Energy Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","typ...

  9. MHK Projects/Treat Island Tidal | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Treat Island Tidal < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type":"ROADMAP"...

  10. MHK Projects/Cook Inlet Tidal Energy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Cook Inlet Tidal Energy < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type":"ROA...

  11. MHK Projects/Paimpol Brehat tidal farm | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Paimpol Brehat tidal farm < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type":"R...

  12. MHK Projects/Guemes Channel Tidal Energy Project | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Guemes Channel Tidal Energy Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3"...

  13. MHK Technologies/Tidal Barrage | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Tidal Barrage.jpg Technology Profile Technology Type Click here Cross Flow Turbine...

  14. MHK Projects/Tacoma Narrows Tidal Energy Project | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Tacoma Narrows Tidal Energy Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3"...

  15. MHK Technologies/TidalStar | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    search << Return to the MHK database homepage TidalStar.jpg Technology Profile Primary Organization Bourne Energy Technology Type Click here Axial Flow Turbine...

  16. MHK Technologies/Tidal Turbine | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Turbine < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Tidal Turbine.jpg Technology Profile Primary Organization Aquascientific Project(s)...

  17. MHK Technologies/Tidal Stream Turbine | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Turbine < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Tidal Stream Turbine.jpg Technology Profile Primary Organization StatoilHydro co owned...

  18. Earth Tidal Analysis At Raft River Geothermal Area (1984) | Open...

    OpenEI (Open Energy Information) [EERE & EIA]

    search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Earth Tidal Analysis At Raft River Geothermal Area (1984) Exploration Activity Details Location Raft River...

  19. Earth Tidal Analysis At Raft River Geothermal Area (1982) | Open...

    OpenEI (Open Energy Information) [EERE & EIA]

    search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Earth Tidal Analysis At Raft River Geothermal Area (1982) Exploration Activity Details Location Raft River...

  20. Earth Tidal Analysis At Raft River Geothermal Area (1980) | Open...

    OpenEI (Open Energy Information) [EERE & EIA]

    search GEOTHERMAL ENERGYGeothermal Home Exploration Activity: Earth Tidal Analysis At Raft River Geothermal Area (1980) Exploration Activity Details Location Raft River...

  1. MHK Technologies/Tidal Stream | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Click here TRL 1-3: Discovery Concept Definition Early Stage Development & Design & Engineering Technology Description The TidalStream SST (Semi-Submersible Turbine) is...

  2. MHK Projects/Tidal Energy Project Portugal | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Organization Tidal Energy Pty Ltd Project Technology *MHK TechnologiesDavidson Hill Venturi DHV Turbine Project Licensing Environmental Monitoring and Mitigation Efforts See...

  3. MHK Projects/Seaflow Tidal Energy System | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    been operating the Seaflow Tidal Energy System project since May 2003. This was an experimental test rig - the successor, SeaGen is intended for commercial applications Project...

  4. OPTICAL DISCOVERY OF PROBABLE STELLAR TIDAL DISRUPTION FLARES

    SciTech Connect

    Van Velzen, Sjoert; Farrar, Glennys R.; Gezari, Suvi; Morrell, Nidia; Zaritsky, Dennis; Oestman, Linda; Smith, Mathew; Gelfand, Joseph; Drake, Andrew J.

    2011-11-10

    Using archival Sloan Digital Sky Survey (SDSS) multi-epoch imaging data (Stripe 82), we have searched for the tidal disruption of stars by supermassive black holes in non-active galaxies. Two candidate tidal disruption events (TDEs) are identified. The TDE flares have optical blackbody temperatures of 2 Multiplication-Sign 10{sup 4} K and observed peak luminosities of M{sub g} = -18.3 and -20.4 ({nu}L{sub {nu}} = 5 Multiplication-Sign 10{sup 42}, 4 Multiplication-Sign 10{sup 43} erg s{sup -1}, in the rest frame); their cooling rates are very low, qualitatively consistent with expectations for tidal disruption flares. The properties of the TDE candidates are examined using (1) SDSS imaging to compare them to other flares observed in the search, (2) UV emission measured by GALEX, and (3) spectra of the hosts and of one of the flares. Our pipeline excludes optically identifiable AGN hosts, and our variability monitoring over nine years provides strong evidence that these are not flares in hidden AGNs. The spectra and color evolution of the flares are unlike any SN observed to date, their strong late-time UV emission is particularly distinctive, and they are nuclear at high resolution arguing against these being first cases of a previously unobserved class of SNe or more extreme examples of known SN types. Taken together, the observed properties are difficult to reconcile with an SN or an AGN-flare explanation, although an entirely new process specific to the inner few hundred parsecs of non-active galaxies cannot be excluded. Based on our observed rate, we infer that hundreds or thousands of TDEs will be present in current and next-generation optical synoptic surveys. Using the approach outlined here, a TDE candidate sample with O(1) purity can be selected using geometric resolution and host and flare color alone, demonstrating that a campaign to create a large sample of TDEs, with immediate and detailed multi-wavelength follow-up, is feasible. A by-product of this

  5. Active Flow Control on Bidirectional Rotors for Tidal MHK Applications

    SciTech Connect

    Shiu, Henry; van Dam, Cornelis P.

    2013-08-22

    A marine and hydrokinetic (MHK) tidal turbine extracts energy from tidal currents, providing clean, sustainable electricity generation. In general, all MHK conversion technologies are confronted with significant operational hurdles, resulting in both increased capital and operations and maintenance (O&M) costs. To counter these high costs while maintaining reliability, MHK turbine designs can be simplified. Prior study found that a tidal turbine could be cost-effectively simplified by removing blade pitch and rotor/nacelle yaw. Its rotor would run in one direction during ebb and then reverse direction when the current switched to flood. We dubbed such a turbine a bidirectional rotor tidal turbine (BRTT). The bidirectional hydrofoils of a BRTT are less efficient than conventional hydrofoils and capture less energy, but the elimination of the pitch and yaw systems were estimated to reduce levelized cost of energy by 7.8%-9.6%. In this study, we investigated two mechanisms for recapturing some of the performance shortfall of the BRTT. First, we developed a novel set of hydrofoils, designated the yy series, for BRTT application. Second, we investigated the use of active flow control via microtabs. Microtabs are small deployable/retractable tabs, typically located near the leading or trailing edge of an air/hydrofoil with height on the order of the boundary layer thickness (1% - 2% of chord). They deploy approximately perpendicularly to the foil surface and, like gurney flaps and plain flaps, globally affect the aerodynamics of the airfoil. By strategically placing microtabs and selectively deploying them based on the direction of the inflow, performance of a BRTT rotor can be improved while retaining bidirectional operation. The yy foils were computationally designed and analyzed. They exhibited better performance than the baseline bidirectional foil, the ellipse. For example, the yyb07cn-180 had 14.7% higher (l/d)max than an ellipse of equal thickness. The yyb07cn

  6. Microsoft Word - Wave Erosion Lesson1.doc

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Wave Erosion Lesson Target Grade Level: 4th Objective: To determine the effects of waves ... Stones carried with a river's current scour and abrade the banks and beds. Ocean waves and ...

  7. EA-1916: Ocean Renewable Power Company Maine, LLC Cobscook Bay Tidal Energy Pilot Project, Cobscook in Washington County, Maine

    Energy.gov [DOE]

    Draft Environmental AssessmentThis EA evaluates the environmental impacts of a project that would use the tidal currents of Cobscook Bay to generate electricity via cross-flow Kinetic System turbine generator units (TGU) mounted on the seafloor. The TGUs would capture energy from the flow in both ebb and flood directions.

  8. Acoustic Monitoring of Beluga Whale Interactions with Cook Inlet Tidal Energy Project

    SciTech Connect

    Worthington, Monty

    2014-02-05

    Cook Inlet, Alaska is home to some of the greatest tidal energy resources in the U.S., as well as an endangered population of beluga whales (Delphinapterus leucas). Successfully permitting and operating a tidal power project in Cook Inlet requires a biological assessment of the potential and realized effects of the physical presence and sound footprint of tidal turbines on the distribution, relative abundance, and behavior of Cook Inlet beluga whales. ORPC Alaska, working with the Project Team—LGL Alaska Research Associates, University of Alaska Anchorage, TerraSond, and Greeneridge Science—undertook the following U.S. Department of Energy (DOE) study to characterize beluga whales in Cook Inlet – Acoustic Monitoring of Beluga Whale Interactions with the Cook Inlet Tidal Energy Project (Project). ORPC Alaska, LLC, is a wholly-owned subsidiary of Ocean Renewable Power Company, LLC, (collectively, ORPC). ORPC is a global leader in the development of hydrokinetic power systems and eco-conscious projects that harness the power of ocean and river currents to create clean, predictable renewable energy. ORPC is developing a tidal energy demonstration project in Cook Inlet at East Foreland where ORPC has a Federal Energy Regulatory Commission (FERC) preliminary permit (P-13821). The Project collected baseline data to characterize pre-deployment patterns of marine mammal distribution, relative abundance, and behavior in ORPC’s proposed deployment area at East Foreland. ORPC also completed work near Fire Island where ORPC held a FERC preliminary permit (P-12679) until March 6, 2013. Passive hydroacoustic devices (previously utilized with bowhead whales in the Beaufort Sea) were adapted for study of beluga whales to determine the relative abundance of beluga whale vocalizations within the proposed deployment areas. Hydroacoustic data collected during the Project were used to characterize the ambient acoustic environment of the project site pre-deployment to inform the

  9. Admiralty Inlet Pilot Tidal Project Final Technical Report

    SciTech Connect

    Collar, Craig

    2015-09-14

    This document represents the final report for the Admiralty Inlet Pilot Tidal Project, located in Puget Sound, Washington, United States. The Project purpose was to license, permit, and install a grid-connected deep-water tidal turbine array (two turbines) to be used as a platform to gather operational and environmental data on tidal energy generation. The data could then be used to better inform the viability of commercial tidal energy generation from technical, economic, social, and environmental standpoints. This data would serve as a critical step towards the responsible advancement of commercial scale tidal energy in the United States and around the world. In late 2014, Project activities were discontinued due to escalating costs, and the DOE award was terminated in early 2015. Permitting, licensing, and engineering design activities were completed under this award. Final design, deployment, operation, and monitoring were not completed. This report discusses the results and accomplishments achieved under the subject award.

  10. SQUARE WAVE AMPLIFIER

    DOEpatents

    Leavitt, M.A.; Lutz, I.C.

    1958-08-01

    An amplifier circuit is described for amplifying sigmals having an alternating current component superimposed upon a direct current component, without loss of any segnnent of the alternating current component. The general circuit arrangement includes a vibrator, two square wave amplifiers, and recombination means. The amplifier input is connected to the vibrating element of the vibrator and is thereby alternately applied to the input of each square wave amplifier. The detailed circuitry of the recombination means constitutes the novelty of the annplifier and consists of a separate, dual triode amplifier coupled to the output of each square wave amplifier with a recombination connection from the plate of one amplifier section to a grid of one section of the other amplifier. The recombination circuit has provisions for correcting distortion caused by overlapping of the two square wave voltages from the square wave amplifiers.

  11. CONSTRAINING TIDAL DISSIPATION IN STARS FROM THE DESTRUCTION RATES OF EXOPLANETS

    SciTech Connect

    Penev, Kaloyan; Jackson, Brian; Spada, Federico; Thom, Nicole

    2012-06-01

    We use the distribution of extrasolar planets in circular orbits around stars with surface convective zones detected by ground-based transit searches to constrain how efficiently tides raised by the planet are dissipated on the parent star. We parameterize this efficiency as a tidal quality factor (Q{sub *}). We conclude that the population of currently known planets is inconsistent with Q{sub *} < 10{sup 7} at the 99% level. Previous studies show that values of Q{sub *} between 10{sup 5} and 10{sup 7} are required in order to explain the orbital circularization of main-sequence low-mass binary stars in clusters, suggesting that different dissipation mechanisms might be acting in the two cases, most likely due to the very different tidal forcing frequencies relative to the stellar rotation frequency occurring for star-star versus planet-star systems.

  12. TIDALLY DRIVEN DYNAMOS IN A ROTATING SPHERE

    SciTech Connect

    Cébron, D.; Hollerbach, R. E-mail: r.hollerbach@leeds.ac.uk

    2014-07-01

    Large-scale planetary or stellar magnetic fields generated by a dynamo effect are mostly attributed to flows forced by buoyancy forces in electrically conducting fluid layers. However, these large-scale fields may also be controlled by tides, as previously suggested for the star τ-boo, Mars, or the early Moon. By simulating a small local patch of a rotating fluid, Barker and Lithwick have recently shown that tides can drive small-scale dynamos by exciting a hydrodynamic instability, the so-called elliptical (or tidal) instability. By performing global magnetohydrodynamic simulations of a rotating spherical fluid body, we investigate if this instability can also drive the observed large-scale magnetic fields. We are thus interested in the dynamo threshold and the generated magnetic field in order to test if such a mechanism is relevant for planets and stars. Rather than solving the problem in a geometry deformed by tides, we consider a spherical fluid body and add a body force to mimic the tidal deformation in the bulk of the fluid. This allows us to use an efficient spectral code to solve the magnetohydrodynamic problem. We first compare the hydrodynamic results with theoretical asymptotic results and numerical results obtained in a truly deformed ellipsoid, which confirms the presence of elliptical instability. We then perform magnetohydrodynamic simulations and investigate the dynamo capability of the flow. Kinematic and self-consistent dynamos are finally simulated, showing that the elliptical instability is capable of generating a dipole-dominated large-scale magnetic field in global simulations of a fluid rotating sphere.

  13. ocean waves

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    waves - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator ... SunShot Grand Challenge: Regional Test Centers ocean waves HomeTag:ocean waves Sandia's ...

  14. Tidal salt marshes of the southeast Atlantic Coast: A community profile

    SciTech Connect

    Wiegert, R.G.; Freeman, B.J.

    1990-09-01

    This report is part of a series of community profiles on the ecology of wetland and marine communities. This particular profile considers tidal marshes of the southeastern Atlantic coast, from North Carolina south to northern Florida. Alone among the earth's ecosystems, coastal communities are subjected to a bidirectional flooding sometimes occurring twice each day; this flooding affects successional development, species composition, stability, and productivity. In the tidally influenced salt marsh, salinity ranges from less than 1 ppt to that of seawater. Dominant plant species include cordgrasses (Spartina alterniflora and S. cynosuroides), black needlerush (Juncus romerianus), and salt marsh bulrush (Scirpus robustus). Both terrestrail and aquatic animals occur in salt marshes and include herons, egrets ospreys (Pandion haliaetus), bald eagles (Haliaeetus leucocephalus), alligators (Alligator Mississippiensis), manatees (Trichecus manatus), oysters, mussels, and fiddler crabs. Currently, the only significant direct commercial use of the tidal salt marshes is by crabbers seeking the blue crab Callinectes sapidus, but the marshes are quite important recreationally, aesthetically, and educationally. 151 refs., 45 figs., 6 tabs.

  15. Pulse Tidal formerly Pulse Generation | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    formerly Pulse Generation Jump to: navigation, search Name: Pulse Tidal (formerly Pulse Generation) Place: Hull, England, United Kingdom Zip: HU5 3LP Product: UK-based developer of...

  16. Assessment of Energy Production Potential from Tidal Streams...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    The project documented in this report created a national database of tidal stream energy potential, as well as a GIS tool usable by industry in order to accelerate the market for ...

  17. Assessment of Energy Production Potential from Tidal Streams...

    Energy.gov [DOE] (indexed site)

    Assessment of Energy Production Potential from Tidal Streams in the United States Final ... Award Number: DE-FG36-08GO18174 Project Title: Assessment of Energy Production Potential ...

  18. Tidal Energy Resource Assessment | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Ocean current resource assessment Free Flow Energy (TRL 1 2 3 Component) - Design and Development of a Cross-Platform Submersible Generator Optimized for the Conditions of Current ...

  19. Application to Export Electric Energy OE Docket No. EA-422 Tidal Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Marketing Inc. | Department of Energy 2 Tidal Energy Marketing Inc. Application to Export Electric Energy OE Docket No. EA-422 Tidal Energy Marketing Inc. Application from Tidal to export electric energy to Canada. EA-422 Tidal Energy Mktg. (CN).pdf (282.23 KB) More Documents & Publications Application to Export Electric Energy OE Docket No. EA-422 Tidal Energy Marketing Inc.: Federal Register Notice, Volume 81, No. 133 - July 12, 2016 Application to Export Electric Energy OE Docket No.

  20. Current-wave spectra coupling project. Volume IV. Part A. Formulation of the three-dimensional structure of storm-generated currents. Part B. Summaries of Volumes I, II and III

    SciTech Connect

    Venezian, G.; Bretschneider, C.L.

    1980-09-01

    An attempt is made to formulate the technical approach to the problem of three dimensional wind driven currents under hurricane conditions. Reference is given to the splendid piece of research on the subject by Forristall (1974) Three-dimensional structure of storm-generated currents, J. Geophys. Res. 79, 2721-2727. The present approach, although not entirely satisfactory, seems to be an improvement on the work by Forristall, but this remains to be verified with future work, including the use of measured data. An improvement could be made if there were some better way of representing the shear stress as a function of the wind velocity (wind speed and direction). It seems that the wind velocity relative to the water motion is what matters, but in turbulent flow the surface value is not well defined. This difficulty leaves one with an unbalanced vortex stretching which accounts for the spin-up of the fluid, but the details of that are lacking. Essentially, it appears that it is feasible to modify Forristall's approach to obtain a more realistic representation of the structure of the boundary layer to take into account the turbulent nature of the flow.

  1. DeFrees Small Wave Basin | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Current Velocity Range(ms) 0.0 Programmable Wavemaking Yes Wavemaking Description Computer controlled hydraulic paddle, arbitrary wave shape possible Wave Direction...

  2. TIDAL DISRUPTION FLARES: THE ACCRETION DISK PHASE

    SciTech Connect

    Montesinos Armijo, Matias; De Freitas Pacheco, Jose A. [Observatoire de la Cote d'Azur, Laboratoire Cassiopee, Universite de Nice Sophia-Antipolis Bd de l'Observatoire, BP 4229, 06304 Nice Cedex 4 (France)

    2011-08-01

    The evolution of an accretion disk, formed as a consequence of the disruption of a star by a black hole, is followed by solving numerically hydrodynamic equations. The present investigation aims to study the dependence of resulting light curves on dynamical and physical properties of such a transient disk during its existence. One of the main results derived from our simulations is that blackbody fits of X-ray data tend to overestimate the true mean disk temperature. In fact, the temperature derived from blackbody fits should be identified with the color X-ray temperature rather than the average value derived from the true temperature distribution along the disk. The time interval between the beginning of the circularization of the bound debris and the beginning of the accretion process by the black hole is determined by the viscous (or accretion) timescale, which also fixes the rising part of the resulting light curve. The luminosity peak coincides with the beginning of matter accretion by the black hole and the late evolution of the light curve depends on the evolution of the debris fallback rate. Peak bolometric luminosities are in the range 10{sup 45}-10{sup 46} erg s{sup -1}, whereas peak luminosities in soft X-rays (0.2-2.0 keV) are typically one order of magnitude lower. The typical timescale derived from our preferred models for the flare luminosity to decay by two orders of magnitude is about 3-4 yr. Predicted soft X-ray light curves reproduce quite well data on galaxies in which a variable X-ray emission possibly related to a tidal event was detected. In the cases of NGC 3599 and IC 3599, data are reproduced well by models defined by a black hole with mass {approx}10{sup 7} M{sub sun} and a disrupted star of about 1 solar mass. The X-ray variation observed in XMMSL1 is consistent with a model defined by a black hole with mass {approx}3 x 10{sup 6} M{sub sun} and a disrupted star of 1 solar mass, while that observed in the galaxy situated in the cluster A

  3. Discovery of a tidal dwarf galaxy in the Leo Triplet

    SciTech Connect

    Nikiel-Wroczy?ski, B.; Soida, M.; Urbanik, M.; Bomans, D. J. E-mail: soida@oa.uj.edu.pl E-mail: bomans@astro.rub.de

    2014-05-10

    We report the discovery of a dwarf galaxy in the Leo Triplet. Analysis of the neutral hydrogen distribution shows that it rotates independently of the tidal tail of NGC 3628, with a radial velocity gradient of 35-40 km s{sup 1} over approximately 13 kpc. The galaxy has an extremely high neutral gas content, accounting for a large amount of its total dynamic mass and suggesting a low amount of dark matter. It is located at the tip of the gaseous tail, which strongly suggests a tidal origin. If this is the case, it would be one of the most confident and nearest (to the Milky Way) detections of a tidal dwarf galaxy and, at the same time, the object most detached from its parent galaxy (?140 kpc) of this type.

  4. Energy Department Awards $10.5 Million for Next-Generation Marine...

    Office of Environmental Management (EM)

    the largely untapped renewable energy in waves, tidal, ocean, and river currents that ... sits on the ocean floor and harnesses energy from the pressure waves beneath ocean waves. ...

  5. Proceedings of the Hydrokinetic and Wave Energy Technologies Technical and Environmental Issues Workshop

    SciTech Connect

    2006-03-01

    Renewable energy technologies offer the promise of non-polluting alternatives to fossil and nuclear-fueled power plants to meet growing demand for electrical energy. Two emerging categories of renewable energy technologies, hydrokinetic and wave energy conversion devices, offer ways to tap the energy of moving water without impoundment (dams) or diversion required by many conventional hydroelectric facilities. These technologies include devices designed for deployment in natural streams, tidal estuaries, ocean currents, and constructed waterways, as well as devices designed to capture the energy of ocean waves. On October 26-28, 2005, 54 representatives from government, non-governmental organizations, and private business met to (1) identify the varieties of hydrokinetic energy and wave technology devices, their stages of development, and the projected cost to bring each to market; (2) identify where these technologies can best operate; (3) identify the potential environmental issues associated with these technologies and possible mitigation measures; (4) develop a list of research needs and/or practical solutions to address unresolved environmental issues. These workshop proceedings include detailed summaries of the 24 presentations made and the discussions that followed.

  6. Assessment of Energy Production Potential from Tidal Streams in the United States

    SciTech Connect

    Haas, Kevin A.; Fritz, Hermann M.; French, Steven P.; Smith, Brennan T.; Neary, Vincent

    2011-06-29

    The project documented in this report created a national database of tidal stream energy potential, as well as a GIS tool usable by industry in order to accelerate the market for tidal energy conversion technology.

  7. Assessment of Energy Production Potential from Tidal Streams in the United States

    Office of Energy Efficiency and Renewable Energy (EERE)

    The project documented in this report created a national database of tidal stream energy potential, as well as a GIS tool usable by industry in order to accelerate the market for tidal energy conversion technology.

  8. Ionization tube simmer current circuit

    DOEpatents

    Steinkraus, R.F. Jr.

    1994-12-13

    A highly efficient flash lamp simmer current circuit utilizes a fifty percent duty cycle square wave pulse generator to pass a current over a current limiting inductor to a full wave rectifier. The DC output of the rectifier is then passed over a voltage smoothing capacitor through a reverse current blocking diode to a flash lamp tube to sustain ionization in the tube between discharges via a small simmer current. An alternate embodiment of the circuit combines the pulse generator and inductor in the form of an FET off line square wave generator with an impedance limited step up output transformer which is then applied to the full wave rectifier as before to yield a similar simmer current. 6 figures.

  9. Ionization tube simmer current circuit

    DOEpatents

    Steinkraus, Jr., Robert F.

    1994-01-01

    A highly efficient flash lamp simmer current circuit utilizes a fifty percent duty cycle square wave pulse generator to pass a current over a current limiting inductor to a full wave rectifier. The DC output of the rectifier is then passed over a voltage smoothing capacitor through a reverse current blocking diode to a flash lamp tube to sustain ionization in the tube between discharges via a small simmer current. An alternate embodiment of the circuit combines the pulse generator and inductor in the form of an FET off line square wave generator with an impedance limited step up output transformer which is then applied to the full wave rectifier as before to yield a similar simmer current.

  10. Application to Export Electric Energy OE Docket No. EA-422 Tidal Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Marketing Inc.: Federal Register Notice, Volume 81, No. 133 - July 12, 2016 | Department of Energy 2 Tidal Energy Marketing Inc.: Federal Register Notice, Volume 81, No. 133 - July 12, 2016 Application to Export Electric Energy OE Docket No. EA-422 Tidal Energy Marketing Inc.: Federal Register Notice, Volume 81, No. 133 - July 12, 2016 Application from Tidal to export electric energy. Federal Register Notice. EA-422 Tidal Energy Mktg. CN.pdf (170.02 KB) More Documents & Publications

  11. wave tank

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    ... the Motion of the Ocean EC, News, Renewable Energy, Water Power Sandia National Laboratories Uses Its Wave Energy Converter (WEC) to Harness the Motion of the Ocean In ...

  12. ON THE EFFICIENCY OF THE TIDAL STIRRING MECHANISM FOR THE ORIGIN OF DWARF SPHEROIDALS: DEPENDENCE ON THE ORBITAL AND STRUCTURAL PARAMETERS OF THE PROGENITOR DISKY DWARFS

    SciTech Connect

    Kazantzidis, Stelios; Lokas, Ewa L.; Callegari, Simone; Mayer, Lucio; Moustakas, Leonidas A. E-mail: lokas@camk.edu.pl E-mail: lucio@phys.ethz.ch

    2011-01-10

    The tidal stirring model posits the formation of dwarf spheroidal galaxies (dSphs) via the tidal interactions between late-type, rotationally supported dwarfs and Milky-Way-sized host galaxies. Using a comprehensive set of collisionless N-body simulations, we investigate the efficiency of the tidal stirring mechanism for the origin of dSphs. In particular, we examine the degree to which the tidal field of the primary galaxy affects the sizes, masses, shapes, and kinematics of the disky dwarfs for a range of dwarf orbital and structural parameters. Our study is the first to employ self-consistent, equilibrium models for the progenitor dwarf galaxies constructed from a composite distribution function and consisting of exponential stellar disks embedded in massive, cosmologically motivated dark matter halos. Exploring a wide variety of dwarf orbital configurations and initial structures, we demonstrate that in the majority of cases the disky dwarfs experience significant mass loss and their stellar distributions undergo a dramatic morphological, as well as dynamical, transformation. Specifically, the stellar components evolve from disks to bars and finally to pressure-supported, spheroidal systems with kinematic and structural properties akin to those of the classic dSphs in the Local Group (LG) and similar environments. The self-consistency of the adopted dwarf models is crucial for confirming this complex transformation process via tidally induced dynamical instabilities and impulsive tidal heating of the stellar distribution. Our results suggest that such tidal transformations should be common occurrences within the currently favored cosmological paradigm and highlight the key factor responsible for an effective metamorphosis to be the strength of the tidal shocks at the pericenters of the orbit. We also demonstrate that the combination of short orbital times and small pericentric distances, characteristic of dwarfs being accreted by their hosts at high redshift

  13. Environmental Effects of Sediment Transport Alteration and Impacts on Protected Species: Edgartown Tidal Energy Project

    SciTech Connect

    Barrett, Stephen B; Schlezinger, David, Ph.D; Cowles, Geoff, Ph.D; Hughes, Patricia; Samimy,; Roland, I; and Terray, E, Ph.D.

    2012-12-29

    The Islands of Martha's Vineyard and Nantucket are separated from the Massachusetts mainland by Vineyard and Nantucket Sounds; water between the two islands flows through Muskeget Channel. The towns of Edgartown (on Martha's Vineyard) and Nantucket recognize that they are vulnerable to power supply interruptions due to their position at the end of the power grid, and due to sea level rise and other consequences of climate change. The tidal energy flowing through Muskeget Channel has been identified by the Electric Power Research Institute as the strongest tidal resource in Massachusetts waters. The Town of Edgartown proposes to develop an initial 5 MW (nameplate) tidal energy project in Muskeget Channel. The project will consist of 14 tidal turbines with 13 providing electricity to Edgartown and one operated by the University of Massachusetts at Dartmouth for research and development. Each turbine will be 90 feet long and 50 feet high. The electricity will be brought to shore by a submarine cable buried 8 feet below the seabed surface which will landfall in Edgartown either on Chappaquiddack or at Katama. Muskeget Channel is located between Martha's Vineyard and Nantucket. Its depth ranges between 40 and 160 feet in the deepest portion. It has strong currents where water is transferred between Nantucket Sound and the Atlantic Ocean continental shelf to the south. This makes it a treacherous passage for navigation. Current users of the channel are commercial and recreational fishing, and cruising boats. The US Coast Guard has indicated that the largest vessel passing through the channel is a commercial scallop dragger with a draft of about 10 feet. The tidal resource in the channel has been measured by the University of Massachusetts-Dartmouth and the peak velocity flow is approximately 5 knots. The technology proposed is the helical Gorlov-type turbine positioned with a horizontal axis that is positively buoyant in the water column and held down by anchors. This is

  14. Modeling In-stream Tidal Energy Extraction and Its Potential Environmental Impacts

    SciTech Connect

    Yang, Zhaoqing; Wang, Taiping; Copping, Andrea; Geerlofs, Simon H.

    2014-09-30

    In recent years, there has been growing interest in harnessing in-stream tidal energy in response to concerns of increasing energy demand and to mitigate climate change impacts. While many studies have been conducted to assess and map tidal energy resources, efforts for quantifying the associated potential environmental impacts have been limited. This paper presents the development of a tidal turbine module within a three-dimensional unstructured-grid coastal ocean model and its application for assessing the potential environmental impacts associated with tidal energy extraction. The model is used to investigate in-stream tidal energy extraction and associated impacts on estuarine hydrodynamic and biological processes in a tidally dominant estuary. A series of numerical experiments with varying numbers and configurations of turbines installed in an idealized estuary were carried out to assess the changes in the hydrodynamics and biological processes due to tidal energy extraction. Model results indicated that a large number of turbines are required to extract the maximum tidal energy and cause significant reduction of the volume flux. Preliminary model results also indicate that extraction of tidal energy increases vertical mixing and decreases flushing rate in a stratified estuary. The tidal turbine model was applied to simulate tidal energy extraction in Puget Sound, a large fjord-like estuary in the Pacific Northwest coast.

  15. New Job Opening in Water Power Program | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    the advancement of innovative wave, tidal, ocean, and river current energy conversion technologies. ... development, demonstration, and deployment of innovative technologies. ...

  16. Ultrasonic probe deployment device for increased wave transmission and

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    rapid area scan inspections - Energy Innovation Portal 087,298 Site Map Printable Version Share this resource About Search Categories (15) Advanced Materials Biomass and Biofuels Building Energy Efficiency Electricity Transmission Energy Analysis Energy Storage Geothermal Hydrogen and Fuel Cell Hydropower, Wave and Tidal Industrial Technologies Solar Photovoltaic Solar Thermal Startup America Vehicles and Fuels Wind Energy Partners (27) Visual Patent Search Success Stories Find More Like

  17. Ultrasonic probe deployment device for increased wave transmission and

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    rapid area scan inspections - Energy Innovation Portal 71,173 Site Map Printable Version Share this resource About Search Categories (15) Advanced Materials Biomass and Biofuels Building Energy Efficiency Electricity Transmission Energy Analysis Energy Storage Geothermal Hydrogen and Fuel Cell Hydropower, Wave and Tidal Industrial Technologies Solar Photovoltaic Solar Thermal Startup America Vehicles and Fuels Wind Energy Partners (27) Visual Patent Search Success Stories Find More Like This

  18. POSSIBLE ORIGIN OF THE G2 CLOUD FROM THE TIDAL DISRUPTION OF A KNOWN GIANT STAR BY SGR A*

    SciTech Connect

    Guillochon, James; Loeb, Abraham; MacLeod, Morgan; Ramirez-Ruiz, Enrico

    2014-05-10

    The discovery of the gas cloud G2 on a near-radial orbit about SgrA* has prompted much speculation on its origin. In this Letter, we propose that G2 formed out of the debris stream produced by the removal of mass from the outer envelope of a nearby giant star. We perform hydrodynamical simulations of the returning tidal debris stream with cooling and find that the stream condenses into clumps that fall periodically onto SgrA*. We propose that one of these clumps is the observed G2 cloud, with the rest of the stream being detectable at lower Br? emissivity along a trajectory that would trace from G2 to the star that was partially disrupted. By simultaneously fitting the orbits of S2, G2, and ?2000 candidate stars, and by fixing the orbital plane of each candidate star to G2 (as is expected for a tidal disruption), we find that several stars have orbits that are compatible with the notion that one of them was tidally disrupted to produce G2. If one of these stars were indeed disrupted, it last encountered SgrA* hundreds of years ago and has likely encountered SgrA* repeatedly. However, while these stars are compatible with the giant disruption scenario given their measured positions and proper motions, their radial velocities are currently unknown. If one of these stars' radial velocity is measured to be compatible with a disruptive orbit, it would strongly suggest that its disruption produced G2.

  19. RBS 1032: A TIDAL DISRUPTION EVENT IN ANOTHER DWARF GALAXY?

    SciTech Connect

    Maksym, W. Peter; Lin, Dacheng; Irwin, Jimmy A.

    2014-09-10

    RBS 1032 is a supersoft (? ? 5), luminous (?10{sup 43} erg s{sup 1}) ROSAT PSPC source which has been associated with an inactive dwarf galaxy at z = 0.026, SDSS J114726.69+494257.8. We have analyzed an XMM-Newton observation that confirms that RBS 1032 is indeed associated with the dwarf galaxy. Moreover, RBS 1032 has undergone a factor of ?100-300 decay since 1990 November. This variability suggests that RBS 1032 may not be a steadily accreting intermediate-mass black hole, but rather an accretion flare from the tidal disruption of a star by the central black hole (which may or may not be intermediate-mass). We suggest that additional tidal disruption events may remain unidentified in archival ROSAT data, such that disruption rate estimates based upon ROSAT All-Sky Survey data may need reconsideration.

  20. EA-1949: Admiralty Inlet Pilot Tidal Project, Puget Sound, WA

    Energy.gov [DOE]

    This EA analyzes the potential environmental effects of a proposal by the Public Utility District No. 1 of Snohomish County, Washington to construct and operate the Admiralty Inlet Tidal Project. The proposed 680-kilowatt project would be located on the east side of Admiralty Inlet in Puget Sound, Washington, about 1 kilometer west of Whidbey Island, entirely within Island County, Washington. The Federal Energy Regulatory Commission (FERC) is the lead agency. The DOE NEPA process for this project has been canceled.

  1. Mirror force induced wave dispersion in Alfvn waves

    SciTech Connect

    Damiano, P. A.; Johnson, J. R.

    2013-06-15

    Recent hybrid MHD-kinetic electron simulations of global scale standing shear Alfvn waves along the Earth's closed dipolar magnetic field lines show that the upward parallel current region within these waves saturates and broadens perpendicular to the ambient magnetic field and that this broadening increases with the electron temperature. Using resistive MHD simulations, with a parallel Ohm's law derived from the linear Knight relation (which expresses the current-voltage relationship along an auroral field line), we explore the nature of this broadening in the context of the increased perpendicular Poynting flux resulting from the increased parallel electric field associated with mirror force effects. This increased Poynting flux facilitates wave energy dispersion across field lines which in-turn allows for electron acceleration to carry the field aligned current on adjacent field lines. This mirror force driven dispersion can dominate over that associated with electron inertial effects for global scale waves.

  2. Collisional disruption of gravitational aggregates in the tidal environment

    SciTech Connect

    Hyodo, Ryuki; Ohtsuki, Keiji

    2014-05-20

    The degree of disruption in collisions in free space is determined by specific impact energy, and the mass fraction of the largest remnant is a monotonically decreasing function of impact energy. However, it has not been shown whether such a relationship is applicable to collisions under the influence of a planet's tidal force, which is important in ring dynamics and satellite accretion. Here we examine the collisional disruption of gravitational aggregates in the tidal environment by using local N-body simulations. We find that outcomes of such a collision largely depend on the impact velocity, the direction of impact, and the radial distance from the planet. In the case of a strong tidal field corresponding to Saturn's F ring, collisions in the azimuthal direction are much more destructive than those in the radial direction. Numerical results of collisions sensitively depend on the impact velocity, and a complete disruption of aggregates can occur even in impacts with velocity much lower than their escape velocity. In such low-velocity collisions, the deformation of colliding aggregates plays an essential role in determining collision outcomes, because the physical size of the aggregate is comparable to its Hill radius. On the other hand, the dependence of collision outcomes on impact velocity becomes similar to the case in free space when the distance from the planet is sufficiently large. Our results are consistent with Cassini observations of the F ring, which suggest ongoing creation and disruption of aggregates within the ring.

  3. Marine Current Turbines Ltd | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    United Kingdom Zip: BS34 8PD Sector: Marine and Hydrokinetic Product: Developer of tidal stream turbine technology for exploiting flowing water in general and tidal streams in...

  4. On the Natural Frequency of Tidal Current Power Systems - A Discussion...

    Office of Scientific and Technical Information (OSTI)

    DOE Contract Number: AC05-76RL01830 Resource Type: Journal Article Resource Relation: Journal Name: Applied Physics Letters, 105(2):Article No. 023902 Research Org: Pacific ...

  5. Maine Deploys First U.S. Commercial, Grid-Connected Tidal Energy Project |

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Department of Energy Maine Deploys First U.S. Commercial, Grid-Connected Tidal Energy Project Maine Deploys First U.S. Commercial, Grid-Connected Tidal Energy Project July 24, 2012 - 1:12pm Addthis NEWS MEDIA CONTACT (202) 586-4940 WASHINGTON -- Today, Energy Secretary Steven Chu recognized the nation's first commercial, grid-connected tidal energy project off the coast of Eastport, Maine. Leveraging a $10 million investment from the Energy Department, Ocean Renewable Power Company (ORPC)

  6. MHK Projects/Long Island Sound Tidal Energy Project | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Long Island Sound Tidal Energy Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemap...

  7. MHK Projects/San Juan Channel Tidal Energy Project | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Juan Channel Tidal Energy Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","...

  8. MHK Projects/San Francisco Bay Tidal Energy Project | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Francisco Bay Tidal Energy Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3",...

  9. MHK Projects/Icy Passage Tidal Energy Project | Open Energy Informatio...

    OpenEI (Open Energy Information) [EERE & EIA]

    Icy Passage Tidal Energy Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","t...

  10. MHK Projects/Ward s Island Tidal Power Project | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    s Island Tidal Power Project < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","type"...

  11. MHK Projects/Hammerfest Strom UK Tidal Stream | Open Energy Informatio...

    OpenEI (Open Energy Information) [EERE & EIA]

    Hammerfest Strom UK Tidal Stream < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","t...

  12. Assessment of Strike of Adult Killer Whales by an OpenHydro Tidal Turbine Blade

    SciTech Connect

    Carlson, Thomas J.; Elster, Jennifer L.; Jones, Mark E.; Watson, Bruce E.; Copping, Andrea E.; Watkins, Michael L.; Jepsen, Richard A.; Metzinger, Kurt

    2012-02-01

    Report to DOE on an analysis to determine the effects of a potential impact to an endangered whale from tidal turbines proposed for deployment in Puget Sound.

  13. EERE Success Story-Measuring the Impact of Tidal Power Installations on

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Endangered Beluga Whales | Department of Energy Measuring the Impact of Tidal Power Installations on Endangered Beluga Whales EERE Success Story-Measuring the Impact of Tidal Power Installations on Endangered Beluga Whales April 9, 2013 - 12:00am Addthis With EERE support, Ocean Renewable Power Company (ORPC) is conducting a two-year study on the effects of tidal turbines on endangered beluga whales in Cook Inlet, Alaska-home to some of the greatest tidal energy potential in the United

  14. MHK Projects/Homeowner Tidal Power Elec Gen | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Homeowner Tidal Power Elec Gen < MHK Projects Jump to: navigation, search << Return to the MHK database homepage Loading map... "minzoom":false,"mappingservice":"googlemaps3","typ...

  15. All Eyes on Eastport: Tidal Energy Project Brings Change, Opportunity to Local Community

    Energy.gov [DOE]

    As progress on a Maine-based tidal energy project moves forward, local community member Gerald Morrison reflects on its impact.

  16. Calming the Waters: The Impact of Turbulence on Tidal Energy Systems

    Office of Energy Efficiency and Renewable Energy (EERE)

    New research is helping the emerging tidal energy industry learn from their counterparts in the wind industry. By considering the effects of atmospheric turbulence when developing turbine designs,...

  17. Current sensor

    DOEpatents

    Yakymyshyn, Christopher Paul; Brubaker, Michael Allen; Yakymyshyn, Pamela Jane

    2007-01-16

    A current sensor is described that uses a plurality of magnetic field sensors positioned around a current carrying conductor. The sensor can be hinged to allow clamping to a conductor. The current sensor provides high measurement accuracy for both DC and AC currents, and is substantially immune to the effects of temperature, conductor position, nearby current carrying conductors and aging.

  18. Mathematical modeling of stormwater pollution in a tidal embayment

    SciTech Connect

    Najjar, K.F.

    1989-01-01

    It has been recognized for many years that stormwater runoff provides a transport mechanism for non-point pollutants into the nation's waterways. As more watershed areas continue to urbanize, greater increases in pollutant loadings will continue to impact the water quality of the receiving water bodies. In many instances, the pollutant impact exceeds the assimilative capacity of the receiving water. To estimate the potential impacts of stormwater pollution, mathematical models are constructed. In this dissertation, mathematical models have been constructed to estimate the non-point pollutant loadings from an urbanizing area as well as to model the assimilative capacity of the receiving tidal embayment system. The models are capable of simulating the hydrologic aspects as well as the water quality cycles of the system as a function of urbanization. In determining the response of the receiving water system to stormwater loadings, the change in receiving water quality is modeled spatially as well as temporally. The overall model is composed of three subsystem models: a stormwater model, a hydrodynamic tidal model, and a receiving water quality model. Construction of the stormwater model is based on STORM (Storage, Treatment, Overflow, Runoff Model) by the US Army Corps of Engineers. A ground water component to the model has been added to adjust the model for application to the study area, Lakes Bay, New Jersey. The tidal model is developed from a pseudo two-dimensional approach. The methodology utilizes the link-node concept to simulate the embayment system. Solutions to equations of motion and continuity are solved using a finite difference method. The receiving water quality model is a two-dimensional time variable water quality model which is based in a finite segment approach.

  19. Enhancing critical current density of cuprate superconductors

    DOEpatents

    Chaudhari, Praveen

    2015-06-16

    The present invention concerns the enhancement of critical current densities in cuprate superconductors. Such enhancement of critical current densities include using wave function symmetry and restricting movement of Abrikosov (A) vortices, Josephson (J) vortices, or Abrikosov-Josephson (A-J) vortices by using the half integer vortices associated with d-wave symmetry present in the grain boundary.

  20. Wave-driven

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    is found to generate internal waves with a characteristic m 2 zonal wave number. ... It is found that a hydrodynamic instability leads to traveling internal waves, their ...

  1. MHK technology developments include...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    for example, hydrokinetic turbines that extract power from water currents (riverine, tidal, and ocean) and wave energy conversion (WEC) devices that extract power from wave motion. ...

  2. Sandia National Laboratories' MHK...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    for example, hydrokinetic turbines that extract power from water currents (riverine, tidal, and ocean) and wave energy conversion (WEC) devices that extract power from wave motion. ...

  3. RED CLUMP STARS IN THE SAGITTARIUS TIDAL STREAMS

    SciTech Connect

    Carrell, Kenneth; Chen Yuqin; Wilhelm, Ronald

    2012-07-15

    We have probed a section (l {approx} 150, b {approx} -60) of the trailing tidal arm of the Sagittarius dwarf spheroidal galaxy by identifying a sample of Red Clump (RC) stream stars. RC stars are not generally found in the halo field, but are found in significant numbers in both the Sagittarius galaxy and its tidal streams, making them excellent probes of stream characteristics. Our target sample was selected using photometric data from the Sloan Digital Sky Survey, Data Release 6, which was constrained in color to match the Sagittarius RC stars. Spectroscopic observations of the target stars were conducted at Kitt Peak National Observatory using the WIYN telescope. The resulting spectroscopic sample is magnitude limited and contains both main-sequence disk stars and evolved RC stars. We have developed a method to systematically separate these two stellar classes using kinematic information and a Bayesian approach for surface gravity determination. The resulting RC sample allows us to determine an absolute stellar density of {rho} = 2.7 {+-} 0.5 RC stars kpc{sup -3} at this location in the stream. Future measurements of stellar densities for a variety of populations and at various locations along the streams will lead to a much improved understanding of the original nature of the Sagittarius galaxy and the physical processes controlling its disruption and subsequent stream generation.

  4. Deflagration Wave Profiles

    SciTech Connect

    Menikoff, Ralph

    2012-04-03

    Shock initiation in a plastic-bonded explosives (PBX) is due to hot spots. Current reactive burn models are based, at least heuristically, on the ignition and growth concept. The ignition phase occurs when a small localized region of high temperature (or hot spot) burns on a fast time scale. This is followed by a growth phase in which a reactive front spreads out from the hot spot. Propagating reactive fronts are deflagration waves. A key question is the deflagration speed in a PBX compressed and heated by a shock wave that generated the hot spot. Here, the ODEs for a steady deflagration wave profile in a compressible fluid are derived, along with the needed thermodynamic quantities of realistic equations of state corresponding to the reactants and products of a PBX. The properties of the wave profile equations are analyzed and an algorithm is derived for computing the deflagration speed. As an illustrative example, the algorithm is applied to compute the deflagration speed in shock compressed PBX 9501 as a function of shock pressure. The calculated deflagration speed, even at the CJ pressure, is low compared to the detonation speed. The implication of this are briefly discussed.

  5. Super massive black hole in galactic nuclei with tidal disruption of stars

    SciTech Connect

    Zhong, Shiyan; Berczik, Peter; Spurzem, Rainer

    2014-09-10

    Tidal disruption of stars by super massive central black holes from dense star clusters is modeled by high-accuracy direct N-body simulation. The time evolution of the stellar tidal disruption rate, the effect of tidal disruption on the stellar density profile, and, for the first time, the detailed origin of tidally disrupted stars are carefully examined and compared with classic papers in the field. Up to 128k particles are used in simulation to model the star cluster around a super massive black hole, and we use the particle number and the tidal radius of the black hole as free parameters for a scaling analysis. The transition from full to empty loss-cone is analyzed in our data, and the tidal disruption rate scales with the particle number, N, in the expected way for both cases. For the first time in numerical simulations (under certain conditions) we can support the concept of a critical radius of Frank and Rees, which claims that most stars are tidally accreted on highly eccentric orbits originating from regions far outside the tidal radius. Due to the consumption of stars moving on radial orbits, a velocity anisotropy is found inside the cluster. Finally we estimate the real galactic center based on our simulation results and the scaling analysis.

  6. Tidal Energy System for On-Shore Power Generation

    SciTech Connect

    Bruce, Allan J

    2012-06-26

    Addressing the urgent need to develop LCOE competitive renewable energy solutions for US energy security and to replace fossil-fuel generation with the associated benefits to environment impacts including a reduction in CO2 emissions, this Project focused on the advantages of using hydraulic energy transfer (HET) in large-scale Marine Hydrokinetic (MHK) systems for harvesting off-shore tidal energy in US waters. A recent DOE resource assessment, identifies water power resources have a potential to meet 15% of the US electric supply by 2030, with MHK technologies being a major component. The work covered a TRL-4 laboratory proof-in-concept demonstration plus modeling of a 15MW full scale system based on an approach patented by NASA-JPL, in which submerged high-ratio gearboxes and electrical generators in conventional MHK turbine systems are replaced by a submerged hydraulic radial pump coupled to on-shore hydraulic motors driving a generator. The advantages are; first, the mean-time-between-failure (MTBF), or maintenance, can be extended from approximately 1 to 5 years and second, the range of tidal flow speeds which can be efficiently harvested can be extended beyond that of a conventional submerged generator. The approach uses scalable, commercial-off-the-shelf (COTS) components, facilitating scale-up and commercialization. All the objectives of the Project have been successfully met (1) A TRL4 system was designed, constructed and tested. It simulates a tidal energy turbine, with a 2-m diameter blade in up to a 2.9 m/sec flow. The system consists of a drive motor assembly providing appropriate torque and RPM, attached to a radial piston pump. The pump circulates pressurized, environmentally-friendly, HEES hydraulic fluid in a closed loop to an axial piston motor which drives an electrical generator, with a resistive load. The performance of the components, subsystems and system were evaluated during simulated tidal cycles. The pump is contained in a tank for

  7. DeFrees Large Wave Basin | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Current Velocity Range(ms) 0.0 Programmable Wavemaking Yes Wavemaking Description Computer controlled 4m hydraulic wave paddle stroke allows a series of solitary waves to be...

  8. EERE Success Story-Making Wave Power Efficient and Affordable |

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Department of Energy Making Wave Power Efficient and Affordable EERE Success Story-Making Wave Power Efficient and Affordable April 10, 2013 - 12:00am Addthis Partnering with Colorado Springs' Atargis Energy, EERE is supporting efforts to design and test wave energy conver-sion devices that can survive significant storms and deliver cost-competitive electricity-two issues that face wave energy conversion devices under development. Atargis is currently testing its Cycloidal Wave Energy

  9. TIDAL HEATING IN A MAGMA OCEAN WITHIN JUPITER’S MOON Io

    SciTech Connect

    Tyler, Robert H.; Henning, Wade G.; Hamilton, Christopher W.

    2015-06-22

    Active volcanism observed on Io is thought to be driven by the temporally periodic, spatially differential projection of Jupiter's gravitational field over the moon. Previous theoretical estimates of the tidal heat have all treated Io as essentially a solid, with fluids addressed only through adjustment of rheological parameters rather than through appropriate extension of the dynamics. These previous estimates of the tidal response and associated heat generation on Io are therefore incomplete and possibly erroneous because dynamical aspects of the fluid behavior are not permitted in the modeling approach. Here we address this by modeling the partial-melt asthenosphere as a global layer of fluid governed by the Laplace Tidal Equations. Solutions for the tidal response are then compared with solutions obtained following the traditional solid-material approach. It is found that the tidal heat in the solid can match that of the average observed heat flux (nominally 2.25 W m{sup −2}), though only over a very restricted range of plausible parameters, and that the distribution of the solid tidal heat flux cannot readily explain a longitudinal shift in the observed (inferred) low-latitude heat fluxes. The tidal heat in the fluid reaches that observed over a wider range of plausible parameters, and can also readily provide the longitudinal offset. Finally, expected feedbacks and coupling between the solid/fluid tides are discussed. Most broadly, the results suggest that both solid and fluid tidal-response estimates must be considered in exoplanet studies, particularly where orbital migration under tidal dissipation is addressed.

  10. Spin Wave Genie

    Energy Science and Technology Software Center

    2015-02-16

    The four-dimensional scattering function S(Q,w) obtained by inelastic neutron scattering measurements provides unique "dynamical fingerprints" of the spin state and interactions present in complex magnetic materials. Extracting this information however is currently a slow and complex process that may take an expert -depending on the complexity of the system- up to several weeks of painstaking work to complete. Spin Wave Genie was created to abstract and automate this process. It strives to both reduce themore » time to complete this analysis and make these calculations more accessible to a broader group of scientists and engineers.« less

  11. Multiscale heterogeneity characterization of tidal channel, tidal delta and foreshore facies, Almond Formation outcrops, Rock Springs uplift, Wyoming

    SciTech Connect

    Schatzinger, R.A.; Tomutsa, L.

    1997-08-01

    In order to accurately predict fluid flow within a reservoir, variability in the rock properties at all scales relevant to the specific depositional environment needs to be taken into account. The present work describes rock variability at scales from hundreds of meters (facies level) to millimeters (laminae) based on outcrop studies of the Almond Formation. Tidal channel, tidal delta and foreshore facies were sampled on the eastern flank of the Rock Springs uplift, southeast of Rock Springs, Wyoming. The Almond Fm. was deposited as part of a mesotidal Upper Cretaceous transgressive systems tract within the greater Green River Basin. Bedding style, lithology, lateral extent of beds of bedsets, bed thickness, amount and distribution of depositional clay matrix, bioturbation and grain sorting provide controls on sandstone properties that may vary more than an order of magnitude within and between depositional facies in outcrops of the Almond Formation. These features can be mapped on the scale of an outcrop. The products of diagenesis such as the relative timing of carbonate cement, scale of cemented zones, continuity of cemented zones, selectively leached framework grains, lateral variability of compaction of sedimentary rock fragments, and the resultant pore structure play an equally important, although less predictable role in determining rock property heterogeneity. A knowledge of the spatial distribution of the products of diagenesis such as calcite cement or compaction is critical to modeling variation even within a single facies in the Almond Fin. because diagenesis can enhance or reduce primary (depositional) rock property heterogeneity. Application of outcrop heterogeneity models to the subsurface is greatly hindered by differences in diagenesis between the two settings. The measurements upon which this study is based were performed both on drilled outcrop plugs and on blocks.

  12. Snohomish PUD No 1 (TRL 7 8 System) - Puget Sound Pilot Tidal Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Project | Department of Energy Snohomish PUD No 1 (TRL 7 8 System) - Puget Sound Pilot Tidal Energy Project Snohomish PUD No 1 (TRL 7 8 System) - Puget Sound Pilot Tidal Energy Project Snohomish PUD No 1 (TRL 7 8 System) - Puget Sound Pilot Tidal Energy Project 01_puget_snopud_presentation.pptx (4.28 MB) More Documents & Publications Ocean Renewable Power Co (ORPC) (TRL 7 8 System) - TidGen (TM) Power System Commercialization Project Vortex Hydro Energy (TRL 5 6 System) - Advanced

  13. Plane wave method for elastic wave scattering by a heterogeneous...

    Office of Scientific and Technical Information (OSTI)

    Plane wave method for elastic wave scattering by a heterogeneous fracture Citation Details In-Document Search Title: Plane wave method for elastic wave scattering by a ...

  14. Unforced, Forced and Resonance-Forced Waves in a Spherical Atmosphere

    SciTech Connect

    Covey, Curt

    2015-10-27

    This technical report discusses a longstanding issue of atmospheric tides in weather-prediction and general circulation models (GCMs). Tidal signatures consistent with observations have appeared in the surface pressure output of GCMs since their inception (Hardy 1968, Hunt and Manabe 1968). Such models, however, are sufficiently complicated that the possibility of “getting the right answer for the wrong reasons” arises. Lindzen et al. (1968, hereafter LBK) showed that wave reflection at the upper boundary of a GCM can artificially enhance the tides. Covey et al. (2011, 2014) found that tidal output from a number of modern GCMs is surprisingly independent of their forcing. This finding is consistent with earlier suggestions that a compensating effect occurs in some models: lowering the model top reduces the forcing (solar heating of the ozone layer) but also enhances spurious wave reflection (Zwiers and Hamilton 1986, Hamilton et al. 2008).

  15. Ecology of Juvenile Salmonids in Shallow Tidal Freshwater Habitats in the Vicinity of the Sandy River Delta, Lower Columbia River, 2007 Annual Report.

    SciTech Connect

    Sobocinski, Kathryn; Johnson, Gary; Sather, Nichole

    2008-03-17

    community characteristics, including species composition, abundance, and temporal and spatial distributions. (1c) Estimate the stock of origin for the yearling and subyearling Chinook salmon captured at the sampling sites using genetic analysis. (1d) Statistically assess the relationship between salmonid abundance and habitat parameters, including ancillary variables such as temperature and river stage. (2) Acoustic Telemetry Monitoring-Assess feasibility of applying Juvenile Salmon Acoustic Telemetry System (JSATS) technology to determine migration characteristics from upriver of Bonneville Dam through the study area (vicinity of the Sandy River delta/Washougal River confluence). (2a) Determine species composition, release locations, and distributions of JSATS-tagged fish. (2b) Estimate run timing, residence times, and migration pathways for these fish. Additionally, both objectives serve the purpose of baseline research for a potential tidal rechannelization project on the Sandy River. The U.S. Forest Service, in partnership with the Bonneville Power Administration and the U.S. Army Corps of Engineers, is currently pursuing reconnection of the east (relict) Sandy River channel with the current channel to improve fish and wildlife habitat in the Sandy River delta. Our study design and the location of sampling sites in this reach provide baseline data to evaluate the potential restoration.

  16. Direct-current-like Phase Space Manipulation Using Chirped Alternating Current Fields

    SciTech Connect

    P.F. Schmit and N.J. Fisch

    2010-02-01

    Waves in plasmas can accelerate particles that are resonant with the wave. A dc electric field also accelerates particles, but without a resonance discrimination, which makes the acceleration mechanism profoundly different. Whereas wave-particle acceleration mechanisms have been widely discussed in the literature, this work discusses the direct analogy between wave acceleration and dc field acceleration in a particular parameter regime explored in previous works. Apart from the academic interest of this correspondence, there may be practical advantages in using waves to mimic dc electric fields, for example, in driving plasma current with high efficiency.

  17. Measurement of the rate of stellar tidal disruption flares

    SciTech Connect

    Van Velzen, Sjoert

    2014-09-01

    We report an observational estimate of the rate of stellar tidal disruption flares (TDFs) in inactive galaxies based on a successful search for these events among transients in galaxies using archival Sloan Digital Sky Survey (SDSS) multi-epoch imaging data (Stripe 82). This search yielded 186 nuclear flares in galaxies, 2 of which are excellent TDF candidates. Because of the systematic nature of the search, the very large number of galaxies, the long time of observation, and the fact that non-TDFs were excluded without resorting to assumptions about TDF characteristics, this study provides an unparalleled opportunity to measure the TDF rate. To compute the rate of optical stellar tidal disruption events, we simulate our entire pipeline to obtain the efficiency of detection. The rate depends on the light curves of TDFs, which are presently still poorly constrained. Using only the observed part of the SDSS light curves gives a model-independent upper limit to the optical TDF rate, N-dot <210{sup ?4} yr{sup ?1} galaxy{sup ?1} (90% CL), under the assumption that the SDSS TDFs are representative examples. We develop three empirical models of the light curves based on the two SDSS light curves and two more recent and better-sampled Pan-STARRS TDF light curves, leading to our best estimate of the rate: N-dot {sub TDF}=(1.5--2.0){sub ?1.3}{sup +2.7}10{sup ?5} yr{sup ?1} galaxy{sup ?1}. We explore the modeling uncertainties by considering two theoretically motivated light curve models, as well as two different relationships between black hole mass and galaxy luminosity, and two different treatments of the cutoff in the visibility of TDFs at large M {sub BH}. From this we conclude that these sources of uncertainty are not significantly larger than the statistical ones. Our results are applicable for galaxies hosting black holes with mass in the range of a few 10{sup 6}-10{sup 8} M {sub ?}, and translates to a volumetric TDF rate of (4-8) 10{sup 80.4} yr{sup 1} Mpc

  18. Snohomish PUD No 1 (TRL 7 8 System) - Puget Sound Pilot Tidal...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Ocean Renewable Power Co (ORPC) (TRL 7 8 System) - TidGen (TM) Power System Commercialization Project Sunlight Photonics (TRL 4 System) - Tidal Energy System for On-shore Power ...

  19. Maine Project Takes Historic Step Forward in U.S. Tidal Energy Deployment

    Energy.gov [DOE]

    A pilot project that will generate electricity from Maine’s ocean tides could be a game-changer for America’s tidal energy industry at-large.

  20. EVIDENCE FOR A MILKY WAY TIDAL STREAM REACHING BEYOND 100 kpc

    SciTech Connect

    Drake, A. J.; Djorgovski, S. G.; Graham, M. J.; Mahabal, A.; Donalek, C.; Williams, R.; Catelan, M.; Torrealba, G.; Prieto, J. L.; Larson, S.; Christensen, E.; Beshore, E.

    2013-03-10

    We present the analysis of 1207 RR Lyrae found in photometry taken by the Catalina Survey's Mount Lemmon telescope. By combining accurate distances for these stars with measurements for {approx}14,000 type-ab RR Lyrae from the Catalina Schmidt telescope, we reveal an extended association that reaches Galactocentric distances beyond 100 kpc and overlaps the Sagittarius stream system. This result confirms earlier evidence for the existence of an outer halo tidal stream resulting from a disrupted stellar system. By comparing the RR Lyrae source density with that expected based on halo models, we find the detection has {approx}8{sigma} significance. We investigate the distances, radial velocities, metallicities, and period-amplitude distribution of the RR Lyrae. We find that both radial velocities and distances are inconsistent with current models of the Sagittarius stream. We also find tentative evidence for a division in source metallicities for the most distant sources. Following prior analyses, we compare the locations and distances of the RR Lyrae with photometrically selected candidate horizontal branch stars and find supporting evidence that this structure spans at least 60 Degree-Sign of the sky. We investigate the prospects of an association between the stream and the unusual globular cluster NGC 2419.

  1. Chris Chartrand

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    ... His research is currently concentrated on development of numerical models for simulating wave, tidal, and current energy capture devices. He is the developer of the WEC power ...

  2. Wave Energy Scotland

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    ... Industry outreach: DOE and Wave Energy Scotland co-sponsored WEC technology workshop News, Partnership, Renewable Energy, Water Power, Workshops Industry outreach: DOE and Wave ...

  3. wave energy testing

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    ... Successful testing of Sandia Labs' Wave Energy Converter (WEC) system News, Partnership, Water Power Successful testing of Sandia Labs' Wave Energy Converter (WEC) system Sandia ...

  4. wave energy industry research

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar ... SunShot Grand Challenge: Regional Test Centers wave energy industry research HomeTag:wave ...

  5. wave energy plant

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Secure & Sustainable Energy Future Stationary Power Energy Conversion Efficiency Solar ... SunShot Grand Challenge: Regional Test Centers wave energy plant HomeTag:wave energy ...

  6. wave energy devices

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    ... WEC-Sim (Wave Energy Converter SIMulator) Code Development and Training Class News, Partnership, Renewable Energy, Water Power WEC-Sim (Wave Energy Converter SIMulator) Code ...

  7. FAINT TIDAL FEATURES IN GALAXIES WITHIN THE CANADA-FRANCE-HAWAII TELESCOPE LEGACY SURVEY WIDE FIELDS

    SciTech Connect

    Atkinson, Adam M.; Abraham, Roberto G.; Ferguson, Annette M. N.

    2013-03-01

    We present an analysis of the detectability of faint tidal features in galaxies from the wide-field component of the Canada-France-Hawaii Telescope Legacy Survey. Our sample consists of 1781 luminous (M{sub r{sup '}}<-19.3 mag) galaxies in the magnitude range 15.5 mag < r' < 17 mag and in the redshift range 0.04 < z < 0.2. Although we have classified tidal features according to their morphology (e.g., streams, shells, and tails), we do not attempt to interpret them in terms of their physical origin (e.g., major versus minor merger debris). Instead, we provide a catalog that is intended to provide raw material for future investigations which will probe the nature of low surface brightness substructure around galaxies. We find that around 12% of the galaxies in our sample show clear tidal features at the highest confidence level. This fraction rises to about 18% if we include systems with convincing, albeit weaker tidal features, and to 26% if we include systems with more marginal features that may or may not be tidal in origin. These proportions are a strong function of rest-frame color and of stellar mass. Linear features, shells, and fans are much more likely to occur in massive galaxies with stellar masses >10{sup 10.5} M {sub Sun }, and red galaxies are twice as likely to show tidal features than are blue galaxies.

  8. A modeling study of the potential water quality impacts from in-stream tidal energy extraction

    DOE PAGES [OSTI]

    Wang, Taiping; Yang, Zhaoqing; Copping, Andrea E.

    2013-11-09

    To assess the effects of tidal energy extraction on water quality in a simplified estuarine system, which consists of a tidal bay connected to the coastal ocean through a narrow channel where energy is extracted using in-stream tidal turbines, a three-dimensional coastal ocean model with built-in tidal turbine and water quality modules was applied. The effects of tidal energy extraction on water quality were examined for two energy extraction scenarios as compared with the baseline condition. It was found, in general, that the environmental impacts associated with energy extraction depend highly on the amount of power extracted from the system.more » Model results indicate that, as a result of energy extraction from the channel, the competition between decreased flushing rates in the bay and increased vertical mixing in the channel directly affects water quality responses in the bay. The decreased flushing rates tend to cause a stronger but negative impact on water quality. On the other hand, the increase of vertical mixing could lead to higher bottom dissolved oxygen at times. As the first modeling effort directly aimed at examining the impacts of tidal energy extraction on estuarine water quality, this study demonstrates that numerical models can serve as a very useful tool for this purpose. Furthermore, more careful efforts are warranted to address system-specific environmental issues in real-world, complex estuarine systems.« less

  9. WATER TRAPPING ON TIDALLY LOCKED TERRESTRIAL PLANETS REQUIRES SPECIAL CONDITIONS

    SciTech Connect

    Yang, Jun; Abbot, Dorian S.; Liu, Yonggang; Hu, Yongyun

    2014-12-01

    Surface liquid water is essential for standard planetary habitability. Calculations of atmospheric circulation on tidally locked planets around M stars suggest that this peculiar orbital configuration lends itself to the trapping of large amounts of water in kilometers-thick ice on the night side, potentially removing all liquid water from the day side where photosynthesis is possible. We study this problem using a global climate model including coupled atmosphere, ocean, land, and sea ice components as well as a continental ice sheet model driven by the climate model output. For a waterworld, we find that surface winds transport sea ice toward the day side and the ocean carries heat toward the night side. As a result, nightside sea ice remains O(10m) thick and nightside water trapping is insignificant. If a planet has large continents on its night side, they can grow ice sheets O(1000m) thick if the geothermal heat flux is similar to Earth's or smaller. Planets with a water complement similar to Earth's would therefore experience a large decrease in sea level when plate tectonics drives their continents onto the night side, but would not experience complete dayside dessiccation. Only planets with a geothermal heat flux lower than Earth's, much of their surface covered by continents, and a surface water reservoir O(10%) of Earth's would be susceptible to complete water trapping.

  10. Application of dynamic displacement current for diagnostics of...

    Office of Scientific and Technical Information (OSTI)

    current was used for diagnostics of ionization processes between the ionization wave front and a plane anode. It is demonstrated that during the generation of a...

  11. MHK Technologies/Zero Impact Water Current Turbine | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Impact Water Current Turbine < MHK Technologies Jump to: navigation, search << Return to the MHK database homepage Technology Profile Primary Organization Green Wave Energy Corp...

  12. Geometry of a naked singularity created by standing waves near a Schwarzschild horizon, and its application to the binary black hole problem

    SciTech Connect

    Mandel, Ilya

    2005-10-15

    The most promising way to compute the gravitational waves emitted by binary black holes (BBHs) in their last dozen orbits, where post-Newtonian techniques fail, is a quasistationary approximation introduced by Detweiler and being pursued by Price and others. In this approximation the outgoing gravitational waves at infinity and downgoing gravitational waves at the holes' horizons are replaced by standing waves so as to guarantee that the spacetime has a helical Killing vector field. Because the horizon generators will not, in general, be tidally locked to the holes' orbital motion, the standing waves will destroy the horizons, converting the black holes into naked singularities that resemble black holes down to near the horizon radius. This paper uses a spherically symmetric, scalar-field model problem to explore in detail the following BBH issues: (i) The destruction of a horizon by the standing waves. (ii) The accuracy with which the resulting naked singularity resembles a black hole. (iii) The conversion of the standing-wave spacetime (with a destroyed horizon) into a spacetime with downgoing waves by the addition of a 'radiation-reaction field'. (iv) The accuracy with which the resulting downgoing waves agree with the downgoing waves of a true black-hole spacetime (with horizon). The model problem used to study these issues consists of a Schwarzschild black hole endowed with spherical standing waves of a scalar field, whose wave frequency and near-horizon energy density are chosen to match those of the standing gravitational waves of the BBH quasistationary approximation. It is found that the spacetime metric of the singular, standing-wave spacetime, and its radiation-reaction-field-constructed downgoing waves are quite close to those for a Schwarzschild black hole with downgoing waves--sufficiently close to make the BBH quasistationary approximation look promising for non-tidally-locked black holes.

  13. THE DYNAMICS, APPEARANCE, AND DEMOGRAPHICS OF RELATIVISTIC JETS TRIGGERED BY TIDAL DISRUPTION OF STARS IN QUIESCENT SUPERMASSIVE BLACK HOLES

    SciTech Connect

    De Colle, Fabio; Guillochon, James; Naiman, Jill; Ramirez-Ruiz, Enrico E-mail: jfg@ucolick.org E-mail: enrico@ucolick.org

    2012-12-01

    We examine the consequences of a model in which relativistic jets can be triggered in quiescent massive black holes when a geometrically thick and hot accretion disk forms as a result of the tidal disruption of a star. To estimate the power, thrust, and lifetime of the jet, we use the mass accretion history onto the black hole as calculated by detailed hydrodynamic simulations of the tidal disruption of stars. We go on to determine the states of the interstellar medium in various types of quiescent galactic nuclei, and describe how this external matter can affect jets propagating through it. We use this information, together with a two-dimensional hydrodynamic model of the structure of the relativistic flow, to study the dynamics of the jet, the propagation of which is regulated by the density stratification of the environment and by its injection history. The breaking of symmetry involved in transitioning from one to two dimensions is crucial and leads to qualitatively new phenomena. At early times, as the jet power increases, the high pressure of the cocoon collimates the jet, increasing its shock velocity as compared to that of spherical models. We show that small velocity gradients, induced near or at the source, steepen into internal shocks and provide a source of free energy for particle acceleration and radiation along the jet's channel. The jets terminate at a working surface where they interact strongly with the surrounding medium through a combination of shock waves and instabilities; a continuous flow of relativistic fluid emanating from the nucleus supplies this region with mass, momentum, and energy. Information about the t {sup -5/3} decrease in power supply propagates within the jet at the internal sound speed. As a result, the internal energy at the jet head continues to accumulate until long after the peak feeding rate is reached. An appreciable time delay is thus expected between peaks in the short-wavelength radiation emanating near the jet

  14. Current Titles

    SciTech Connect

    Various

    2006-06-01

    This booklet is published for those interested in current research being conducted at the National Center for Electron Microscopy. The NCEM is a DOE-designated national user facility and is available at no charge to qualified researchers. Access is controlled by an external steering committee. Interested researchers may contact Jane Cavlina, Administrator, at 510/486-6036.

  15. Gravitational waves from gravitational collapse

    SciTech Connect

    Fryer, Christopher L; New, Kimberly C

    2008-01-01

    Gravitational wave emission from stellar collapse has been studied for nearly four decades. Current state-of-the-art numerical investigations of collapse include those that use progenitors with more realistic angular momentum profiles, properly treat microphysics issues, account for general relativity, and examine non-axisymmetric effects in three dimensions. Such simulations predict that gravitational waves from various phenomena associated with gravitational collapse could be detectable with ground-based and space-based interferometric observatories. This review covers the entire range of stellar collapse sources of gravitational waves: from the accretion induced collapse of a white dwarf through the collapse down to neutron stars or black holes of massive stars to the collapse of supermassive stars.

  16. Wintertime current meter measurements from the East China Sea

    SciTech Connect

    Trump, C.L.; Burt, W.V.

    1981-09-01

    An array of three current meters were anchored on the continental shelf of the East China Sea during the last half of February 1975 as part of the Japanese Air Mass Transformation Experiment, AMTEX-75. The results indicate that the currents are dominated by the rotational semidiurnal M/sub 2/ tidal component superimposed on a slow mean drift to the northeast. Differences in direction of several days duration between two of the current meters suggest the presence of transient mesoscale eddies or meanders in the flow regime.

  17. Evolution of accretion disks in tidal disruption events

    SciTech Connect

    Shen, Rong-Feng; Matzner, Christopher D. E-mail: matzner@astro.utoronto.ca

    2014-04-01

    During a stellar tidal disruption event (TDE), an accretion disk forms as stellar debris returns to the disruption site and circularizes. Rather than being confined within the circularizing radius, the disk can spread to larger radii to conserve angular momentum. A spreading disk is a source of matter for re-accretion at rates that may exceed the later stellar fallback rate, although a disk wind can suppress its contribution to the central black hole accretion rate. A spreading disk is detectible through a break in the central accretion rate history or, at longer wavelengths, by its own emission. We model the evolution of TDE disk size and accretion rate by accounting for the time-dependent fallback rate, for the influence of wind losses in the early advective stage, and for the possibility of thermal instability for accretion rates intermediate between the advection-dominated and gas-pressure-dominated states. The model provides a dynamic basis for modeling TDE light curves. All or part of a young TDE disk will precess as a solid body because of the Lense-Thirring effect, and precession may manifest itself as a quasi-periodic modulation of the light curve. The precession period increases with time. Applying our results to the jetted TDE candidate Swift J1644+57, whose X-ray light curve shows numerous quasi-periodic dips, we argue that the data best fit a scenario in which a main-sequence star was fully disrupted by an intermediate mass black hole on an orbit significantly inclined from the black hole equator, with the apparent jet shutoff at t = 500 days corresponding to a disk transition from the advective state to the gas-pressure-dominated state.

  18. Current Contracts

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Current Contracts U.S. Department of Energy Carlsbad Field Office Management & Operating Contractor for the Waste Isolation Pilot Plant Contract Number DE-EM0001971 Fee Payment Information (Nuclear Waste Partnership, LLC.) U.S. Department of Energy Carlsbad Field Office Transportation Contractors for the Waste Isolation Pilot Plant Contract Number DE-EM0001840 (Visionary Solutions, LLC) Contract Number DE-EM0001819 (CAST Specialty Transportation Services, Inc.) U.S. Department of Energy

  19. Current Research

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Current Research The U.S. Department of Transportation (USDOT) has established its only high-performance computing and engineering analysis research facility at Argonne National Laboratory to provide applications support in key areas of applied research and development for the USDOT community. The Transportation Research and Analysis Computing Center (TRACC) features a state-of-the-art massively parallel computer system, advanced scientific visualization capability, high-speed network

  20. Modeling of In-stream Tidal Energy Development and its Potential Effects in Tacoma Narrows, Washington, USA

    SciTech Connect

    Yang, Zhaoqing; Wang, Taiping; Copping, Andrea E.; Geerlofs, Simon H.

    2014-10-01

    Understanding and providing proactive information on the potential for tidal energy projects to cause changes to the physical system and to key water quality constituents in tidal waters is a necessary and cost-effective means to avoid costly regulatory involvement and late stage surprises in the permitting process. This paper presents a modeling study for evaluating the tidal energy extraction and its potential impacts on the marine environment in a real world site - Tacoma Narrows of Puget Sound, Washington State, USA. An unstructured-grid coastal ocean model, fitted with a module that simulates tidal energy devices, was applied to simulate the tidal energy extracted by different turbine array configurations and the potential effects of the extraction at local and system-wide scales in Tacoma Narrows and South Puget Sound. Model results demonstrated the advantage of an unstructured-grid model for simulating the far-field effects of tidal energy extraction in a large model domain, as well as assessing the near-field effect using a fine grid resolution near the tidal turbines. The outcome shows that a realistic near-term deployment scenario extracts a very small fraction of the total tidal energy in the system and that system wide environmental effects are not likely; however, near-field effects on the flow field and bed shear stress in the area of tidal turbine farm are more likely. Model results also indicate that from a practical standpoint, hydrodynamic or water quality effects are not likely to be the limiting factor for development of large commercial-scale tidal farms. Results indicate that very high numbers of turbines are required to significantly alter the tidal system; limitations on marine space or other environmental concerns are likely to be reached before reaching these deployment levels. These findings show that important information obtained from numerical modeling can be used to inform regulatory and policy processes for tidal energy development.

  1. Variational symplectic particle-in-cell simulation of nonlinear mode conversion from extraordinary waves to Bernstein waves

    SciTech Connect

    Xiao, Jianyuan; Liu, Jian; Qin, Hong; Yu, Zhi; Xiang, Nong

    2015-09-15

    In this paper, the nonlinear mode conversion of extraordinary waves in nonuniform magnetized plasmas is studied using the variational symplectic particle-in-cell simulation. The accuracy of the nonlinear simulation is guaranteed by the long-term accuracy and conservativeness of the symplectic algorithm. The spectra of the electromagnetic wave, the evolution of the wave reflectivity, the energy deposition profile, and the parameter-dependent properties of radio-frequency waves during the nonlinear mode conversion are investigated. It is illustrated that nonlinear effects significantly modify the physics of the radio-frequency injection in magnetized plasmas. The evolutions of the radio-frequency wave reflectivity and the energy deposition are observed, as well as the self-interaction of the Bernstein waves and mode excitations. Even for waves with small magnitude, nonlinear effects can also become important after continuous wave injections, which are common in the realistic radio-frequency wave heating and current drive experiments.

  2. Sandia Energy - Tidal Energy Resource Assessment in the East...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    current at the site is highly regular, which is desirable because it allows accurate electricity supply forecasting. The mean ebb and mean flood flow directions are nearly...

  3. MHK Projects/Gastineau Channel Tidal | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Organization Natural Currents Energy Services Project Technology *MHK TechnologiesRED HAWK Project Licensing FERC License Docket Number P-13606 Environmental Monitoring and...

  4. MHK Projects/Fishers Island Tidal Energy Project | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Organization Natural Currents Energy Services Project Technology *MHK TechnologiesRED HAWK Project Licensing FERC License Docket Number P-14395 Environmental Monitoring and...

  5. MHK Projects/Shelter Island Tidal Energy Project | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Organization Natural Currents Energy Services Project Technology *MHK TechnologiesRED HAWK Project Licensing Environmental Monitoring and Mitigation Efforts See Tethys <<...

  6. MHK Projects/Dorchester Maurice Tidal | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Organization Natural Currents Energy Services Project Technology *MHK TechnologiesRED HAWK Project Licensing FERC License Docket Number P-14223 Environmental Monitoring and...

  7. MHK Projects/Margate Tidal | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Organization Natural Currents Energy Services Project Technology *MHK TechnologiesRED HAWK Project Licensing FERC License Docket Number P-14224 Environmental Monitoring and...

  8. MHK Projects/Wiscasset Tidal Energy Plant | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Organization Natural Currents Energy Services Project Technology *MHK TechnologiesRED HAWK Project Licensing Environmental Monitoring and Mitigation Efforts See Tethys <<...

  9. MHK Projects/Orient Point Tidal | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Organization Natural Currents Energy Services Project Technology *MHK TechnologiesRED HAWK Project Licensing FERC License Docket Number P-14333 Environmental Monitoring and...

  10. MHK Projects/Cohansey River Tidal Energy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Organization Natural Currents Energy Services Project Technology *MHK TechnologiesRED HAWK Project Licensing FERC License Docket Number P-14127 Environmental Monitoring and...

  11. MHK Projects/BW2 Tidal | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Organization Natural Currents Energy Services Project Technology *MHK TechnologiesRED HAWK Project Licensing FERC License Docket Number P-14222 Environmental Monitoring and...

  12. MHK Projects/Maurice River Tidal | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Organization Natural Currents Energy Services Project Technology *MHK TechnologiesRED HAWK Project Licensing FERC License Docket Number P-14234 Environmental Monitoring and...

  13. MHK Projects/Salem Tidal Energy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Organization Natural Currents Energy Services Project Technology *MHK TechnologiesRED HAWK Project Licensing FERC License Docket Number P-13849 Environmental Monitoring and...

  14. MHK Projects/Cape May Tidal Energy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Organization Natural Currents Energy Services Project Technology *MHK TechnologiesRED HAWK Project Licensing FERC License Docket Number P-14232 Environmental Monitoring and...

  15. MHK Projects/Killisnoo Tidal Energy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Organization Natural Currents Energy Services Project Technology *MHK TechnologiesRED HAWK Project Licensing FERC License Docket Number P-13823 Environmental Monitoring and...

  16. MHK Projects/Rockaway Tidal Energy Plant | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Organization Natural Currents Energy Services Project Technology *MHK TechnologiesRED HAWK Project Licensing Environmental Monitoring and Mitigation Efforts See Tethys <<...

  17. Spitzer view of massive star formation in the tidally stripped Magellanic Bridge

    SciTech Connect

    Chen, C.-H. Rosie; Indebetouw, Remy; Muller, Erik; Kawamura, Akiko; Gordon, Karl D.; Meixner, Margaret; Seale, Jonathan P.; Shiao, Bernie; Sewiło, Marta; Whitney, Barbara A.; Meade, Marilyn R.; Fukui, Yasuo; Madden, Suzanne C.; Robitaille, Thomas P.

    2014-04-20

    The Magellanic Bridge is the nearest low-metallicity, tidally stripped environment, offering a unique high-resolution view of physical conditions in merging and forming galaxies. In this paper, we present an analysis of candidate massive young stellar objects (YSOs), i.e., in situ, current massive star formation (MSF) in the Bridge using Spitzer mid-IR and complementary optical and near-IR photometry. While we definitely find YSOs in the Bridge, the most massive are ∼10 M {sub ☉}, <<45 M {sub ☉} found in the LMC. The intensity of MSF in the Bridge also appears to be decreasing, as the most massive YSOs are less massive than those formed in the past. To investigate environmental effects on MSF, we have compared properties of massive YSOs in the Bridge to those in the LMC. First, YSOs in the Bridge are apparently less embedded than in the LMC: 81% of Bridge YSOs show optical counterparts, compared to only 56% of LMC sources with the same range of mass, circumstellar dust mass, and line-of-sight extinction. Circumstellar envelopes are evidently more porous or clumpy in the Bridge's low-metallicity environment. Second, we have used whole samples of YSOs in the LMC and the Bridge to estimate the probability of finding YSOs at a given H I column density, N(H I). We found that the LMC has ∼3 × higher probability than the Bridge for N(H I) >12 × 10{sup 20} cm{sup –2}, but the trend reverses at lower N(H I). Investigating whether this lower efficiency relative to H I is due to less efficient molecular cloud formation or to less efficient cloud collapse, or to both, will require sensitive molecular gas observations.

  18. BINARY DISRUPTION BY MASSIVE BLACK HOLES: HYPERVELOCITY STARS, S STARS, AND TIDAL DISRUPTION EVENTS

    SciTech Connect

    Bromley, Benjamin C.; Kenyon, Scott J.; Geller, Margaret J.; Brown, Warren R. E-mail: skenyon@cfa.harvard.edu E-mail: wbrown@cfa.harvard.edu

    2012-04-20

    We examine whether disrupted binary stars can fuel black hole growth. In this mechanism, tidal disruption produces a single hypervelocity star (HVS) ejected at high velocity and a former companion star bound to the black hole. After a cluster of bound stars forms, orbital diffusion allows the black hole to accrete stars by tidal disruption at a rate comparable to the capture rate. In the Milky Way, HVSs and the S star cluster imply similar rates of 10{sup -5} to 10{sup -3} yr{sup -1} for binary disruption. These rates are consistent with estimates for the tidal disruption rate in nearby galaxies and imply significant black hole growth from disrupted binaries on 10 Gyr timescales.

  19. Tidal dissipation in a homogeneous spherical body. II. Three examples: Mercury, Io, and Kepler-10 b

    SciTech Connect

    Makarov, Valeri V.; Efroimsky, Michael E-mail: michael.efroimsky@usno.navy.mil

    2014-11-01

    In Efroimsky and Makarov (Paper I), we derived from the first principles a formula for the tidal heating rate in a homogeneous sphere, compared it with the previously used formulae, and noted the differences. Now we present case studies: Mercury, Kepler-10 b, and a triaxial Io. A sharp frequency dependence of k {sub 2}/Q near spin-orbit resonances yields a sharp dependence of k {sub 2}/Q (and, therefore, of tidal heating) upon the spin rate. Thereby physical libration plays a major role in tidal heating of synchronously rotating planets. The magnitude of libration in the spin rate being defined by the planet's triaxiality, the latter becomes a factor determining the dissipation rate. Other parameters equal, a strongly triaxial synchronized body generates more heat than a similar body of a more symmetrical shape. After an initially triaxial object melts and loses its triaxiality, dissipation becomes less intensive; the body can solidify, with the tidal bulge becoming a new figure with triaxiality lower than the original. We derive approximate expressions for the dissipation rate in a Maxwell planet with the Maxwell time longer than the inverse tidal frequency. The expressions derived pertain to the 1:1 and 3:2 resonances and a nonresonant case; so they are applicable to most close-in super-Earths detected. In these planets, the heating outside synchronism is weakly dependent on the eccentricity and obliquity, provided both these parameters's values are moderate. According to our calculation, Kepler-10 b could hardly survive the intensive tidal heating without being synchronized, circularized, and reshaped through a complete or partial melt-down.

  20. Detonation Wave Profile

    SciTech Connect

    Menikoff, Ralph

    2015-12-14

    The Zel’dovich-von Neumann-Doering (ZND) profile of a detonation wave is derived. Two basic assumptions are required: i. An equation of state (EOS) for a partly burned explosive; P(V, e, λ). ii. A burn rate for the reaction progress variable; d/dt λ = R(V, e, λ). For a steady planar detonation wave the reactive flow PDEs can be reduced to ODEs. The detonation wave profile can be determined from an ODE plus algebraic equations for points on the partly burned detonation loci with a specified wave speed. Furthermore, for the CJ detonation speed the end of the reaction zone is sonic. A solution to the reactive flow equations can be constructed with a rarefaction wave following the detonation wave profile. This corresponds to an underdriven detonation wave, and the rarefaction is know as a Taylor wave.

  1. Puget Sound Tidal Energy In-Water Testing and Development Project Final Technical Report

    SciTech Connect

    Craig W. Collar

    2012-11-16

    Tidal energy represents potential for the generation of renewable, emission free, environmentally benign, and cost effective energy from tidal flows. A successful tidal energy demonstration project in Puget Sound, Washington may enable significant commercial development resulting in important benefits for the northwest region and the nation. This project promoted the United States Department of Energy’s Wind and Hydropower Technologies Program’s goals of advancing the commercial viability, cost-competitiveness, and market acceptance of marine hydrokinetic systems. The objective of the Puget Sound Tidal Energy Demonstration Project is to conduct in-water testing and evaluation of tidal energy technology as a first step toward potential construction of a commercial-scale tidal energy power plant. The specific goal of the project phase covered by this award was to conduct all activities necessary to complete engineering design and obtain construction approvals for a pilot demonstration plant in the Admiralty Inlet region of the Puget Sound. Public Utility District No. 1 of Snohomish County (The District) accomplished the objectives of this award through four tasks: Detailed Admiralty Inlet Site Studies, Plant Design and Construction Planning, Environmental and Regulatory Activities, and Management and Reporting. Pre-Installation studies completed under this award provided invaluable data used for site selection, environmental evaluation and permitting, plant design, and construction planning. However, these data gathering efforts are not only important to the Admiralty Inlet pilot project. Lessons learned, in particular environmental data gathering methods, can be applied to future tidal energy projects in the United States and other parts of the world. The District collaborated extensively with project stakeholders to complete the tasks for this award. This included Federal, State, and local government agencies, tribal governments, environmental

  2. Catching a Wave: Innovative Wave Energy Device Surfs for Power...

    Office of Environmental Management (EM)

    Catching a Wave: Innovative Wave Energy Device Surfs for Power in Hawaii Catching a Wave: Innovative Wave Energy Device Surfs for Power in Hawaii July 29, 2015 - 12:00pm Addthis...

  3. Current Schedule of Experiments

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    current schedule of experiments Current Schedule of Experiments Current Schedule of Experiments - Updated 4/2016

  4. Property:Project Resource | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    property. (previous 25) (next 25) M MHK Projects + Current Tidal MHK Projects40MW Lewis project + Wave MHK ProjectsADM 3 + Wave MHK ProjectsADM 4 + Wave MHK ProjectsADM 5...

  5. Marine and Hydrokinetic Resources | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Contents 1 Marine and Hydrokinetic Resource Assessment and Characterization 2 CurrentTidalRiverine 3 Wave 4 Ocean Thermal Energy Conversion (OTEC) Marine and Hydrokinetic...

  6. An Assessment of Lifecycle Cost in the U.S. over Time

    SciTech Connect

    Previsic, Mirko

    2011-10-06

    Presentation from the 2011 Water Peer Review in which principal investigator discussed project progress to assess Lifecycle cost of Wave, Tidal, River, and Ocean Current Technologies

  7. Marine and Hydrokinetic Market Acceleration and Deployment |...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    robust portfolio of projects to accelerate wave, tidal and current project deployments and ... Learn more about the Water Power Program's work in the following areas of marine and ...

  8. Infrastructure Security EXCEPTIONAL SERVICE IN THE NATIONAL INTEREST

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    By identifying and developing materials and manufacturing processes that advance the performance and reliability of both wave and current tidal power devices, Sandia advances the ...

  9. Performance | OpenEI Community

    OpenEI (Open Energy Information) [EERE & EIA]

    Submitted by Ocop(5) Member 15 July, 2014 - 07:07 MHK LCOE Reporting Guidance Draft Cost Current DOE LCOE numerical modeling Performance Tidal Wave To normalize competing...

  10. numerical modeling | OpenEI Community

    OpenEI (Open Energy Information) [EERE & EIA]

    Submitted by Ocop(5) Member 15 July, 2014 - 07:07 MHK LCOE Reporting Guidance Draft Cost Current DOE LCOE numerical modeling Performance Tidal Wave To normalize competing...

  11. Tax Credits, Rebates & Savings | Department of Energy

    Energy.gov [DOE] (indexed site)

    Municipal Solid Waste, Landfill Gas, Tidal, Wave, Wind (Small) Delmarva Power- Green Energy Program Incentives NOTE: The Green Energy Fund regulations are currently...

  12. Sandia Energy - DOE-Sponsored Reference Model Project Results...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    partnered effort to develop marine hydrokinetic (MHK) reference models (RMs) for wave energy converters and tidal, ocean, and river current energy converters. The RMP team...

  13. Marine and Hydrokinetic Resources | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    and Characterization 2 CurrentTidalRiverine 3 Wave 4 Ocean Thermal Energy Conversion (OTEC) Marine and Hydrokinetic Resource Assessment and Characterization To find out more...

  14. ORNL TM Report Template

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    difficult in large rivers and tidal channels where depths commonly exceed several meters, currents are greater than 1ms and surface waves and turbulence are generated by...

  15. Energy Department Accepting Small Business Grant Applications...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    systems optimized for use in tidal, current, wave, andor ocean thermal energy converters. ... For more information on water power research, development, testing, and deployment, ...

  16. Current to Current | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Current Jump to: navigation, search Name: Current to Current Address: 35 Corporate Dr Place: Burlington Zip: 1803 Region: United States Sector: Marine and Hydrokinetic Phone...

  17. Current generation by minority species heating

    SciTech Connect

    Fisch, N.J.

    1980-07-01

    It is proposed that electric currents be generated from the preferential heating of ions traveling in one direction but with no net momentum injected into the system. This can be accomplished with, for example, traveling waves in a two-ion-species plasma. The current can be generated efficiently enough for the scheme to be of interest in maintaining steady-state toroidal currents in a reactor.

  18. PROSPECTS FOR JOINT GRAVITATIONAL-WAVE AND ELECTROMAGNETIC OBSERVATIONS OF NEUTRON-STAR-BLACK-HOLE COALESCING BINARIES

    SciTech Connect

    Pannarale, Francesco; Ohme, Frank E-mail: frank.ohme@ligo.org

    2014-08-10

    Coalescing neutron-star-black-hole (NS-BH) binaries are a promising source of gravitational-wave (GW) signals detectable with large-scale laser interferometers such as the Advanced Laser Interferometer Gravitational-Wave Observatory and Virgo. They are also one of the main short gamma-ray burst (SGRB) progenitor candidates. If the black hole (BH) tidally disrupts its companion, an SGRB may be ignited when a sufficiently massive accretion disk forms around the remnant BH. Detecting an NS-BH coalescence both in the GW and electromagnetic (EM) spectrum offers a wealth of information about the nature of the source. How much can actually be inferred from a joint detection is unclear, however, as a mass/spin degeneracy may reduce the GW measurement accuracy. To shed light on this problem and on the potential of joint EM+GW observations, we here combine recent semi-analytical predictions for the remnant disk mass with estimates of the parameter-space portion that is selected by a GW detection. We identify cases in which an SGRB ignition is supported, others in which it can be excluded, and finally others in which the outcome depends on the chosen model for the currently unknown NS equation of state. We pinpoint a range of systems that would allow us to place lower bounds on the equation of state stiffness if both the GW emission and its EM counterpart are observed. The methods we develop can broaden the scope of existing GW detection and parameter-estimation algorithms and could allow us to disregard about half of the templates in an NS-BH search following an SGRB trigger, increasing its speed and sensitivity.

  19. OCCULTATION OF THE T TAURI STAR RW AURIGAE A BY ITS TIDALLY DISRUPTED DISK

    SciTech Connect

    Rodriguez, Joseph E.; Stassun, Keivan G.; Pepper, Joshua; Siverd, Robert J.; Cargile, Phillip; Beatty, Thomas G.; Gaudi, B. Scott

    2013-11-01

    RW Aur A is a classical T Tauri star, believed to have undergone a reconfiguration of its circumstellar environment as a consequence of a recent flyby of its stellar companion, RW Aur B. This interaction stripped away part of the circumstellar disk of RW Aur A, leaving a tidally disrupted ''arm'' and a short truncated circumstellar disk. We present photometric observations of the RW Aur system from the Kilodegree Extremely Little Telescope survey showing a long and deep dimming that occurred from 2010 September until 2011 March. The dimming has a depth of ?2 mag, a duration of ?180 days, and was confirmed by archival observations from American Association of Variable Star Observers. We suggest that this event is the result of a portion of the tidally disrupted disk occulting RW Aur A, specifically a fragment of the tidally disrupted arm. The calculated transverse linear velocity of the occulter is in excellent agreement with the measured relative radial velocity of the tidally disrupted arm. Using simple kinematic and geometric arguments, we show that the occulter cannot be a feature of the RW Aur A circumstellar disk, and we consider and discount other hypotheses. We also place constraints on the thickness and semimajor axis of the portion of the arm that occulted the star.

  20. TIDAL INTERACTION AS THE ORIGIN OF EARLY-TYPE DWARF GALAXIES IN GROUP ENVIRONMENTS

    SciTech Connect

    Paudel, Sanjaya; Ree, Chang H.

    2014-11-20

    We present a sample of dwarf galaxies that suffer ongoing disruption by the tidal forces of nearby massive galaxies. By analyzing structural and stellar population properties using the archival imaging and spectroscopic data from the Sloan Digital Sky Survey (SDSS), we find that they are likely a ''smoking gun'' example of the formation through tidal stirring of early-type dwarf galaxies (dEs) in the galaxy group environment. The inner cores of these galaxies are fairly intact and the observed light profiles are well fit by the Srsic functions while the tidally stretched stellar halos are prominent in the outer parts. They are all located within a sky-projected distance of 50 kpc from the centers of the host galaxies and no dwarf galaxies have relative line-of-sight velocities larger than 205 km s{sup 1} to their hosts. We derive the Composite Stellar Population properties of these galaxies by fitting the SDSS optical spectra to a multiple-burst composite stellar population model. We find that these galaxies accumulate a significant fraction of stellar mass within the last 1 Gyr and contain a majority stellar population with an intermediate age of 2 to 4 Gyr. Based on this evidence, we argue that tidal stirring, particularly through the galaxy-galaxy interaction, might have an important role in the formation and evolution of dEs in the group environment where the influence of other gas stripping mechanism might be limited.

  1. Energy Department Awards $7.4 Million to Develop Advanced Components for Wave and Tidal Energy Systems

    Energy.gov [DOE]

    The Energy Department today announced four entities selected to receive $7.4 million to spur innovation of next-generation water power component technologies, designed for manufacturability and built specifically for marine and hydrokinetic systems.

  2. Riding the Clean Energy Wave: New Projects Aim to Improve Water...

    Energy Saver

    the energy of the ocean's waves, tides, and currents and convert it into electricity. ... With up to 1,400 terawatt hours of potential power generation per year, our nation's waves ...

  3. Scattering of Radio Frequency Waves by Edge Density Blobs in Tokamak Plasmas

    SciTech Connect

    Ram, A. K.; Hizanidis, K.; Kominis, Y.

    2011-12-23

    The density blobs and fluctuations present in the edge region of magnetic fusion devices can scatter radio frequency (RF) waves through refraction and diffraction. The scattering can diffuse the rays in space and in wave-vector space. The diffusion in space can make the rays miss their intended target region, while the diffusion in wave-vector space can broaden the wave spectrum and modify the wave damping and current profile.

  4. THE TIDAL DISRUPTION OF GIANT STARS AND THEIR CONTRIBUTION TO THE FLARING SUPERMASSIVE BLACK HOLE POPULATION

    SciTech Connect

    MacLeod, Morgan; Guillochon, James; Ramirez-Ruiz, Enrico E-mail: jfg@ucolick.org

    2012-10-01

    Sun-like stars are thought to be regularly disrupted by supermassive black holes (SMBHs) within galactic nuclei. Yet, as stars evolve off the main sequence their vulnerability to tidal disruption increases drastically as they develop a bifurcated structure consisting of a dense core and a tenuous envelope. Here we present the first hydrodynamic simulations of the tidal disruption of giant stars and show that the core has a substantial influence on the star's ability to survive the encounter. Stars with more massive cores retain large fractions of their envelope mass, even in deep encounters. Accretion flares resulting from the disruption of giant stars should last for tens to hundreds of years. Their characteristic signature in transient searches would not be the t {sup -5/3} decay typically associated with tidal disruption events, but a correlated rise over many orders of magnitude in brightness on timescales of months to years. We calculate the relative disruption rates of stars of varying evolutionary stages in typical galactic centers, then use our results to produce Monte Carlo realizations of the expected flaring event populations. We find that the demographics of tidal disruption flares are strongly dependent on both stellar and black hole mass, especially near the limiting SMBH mass scale of {approx}10{sup 8} M{sub Sun }. At this black hole mass, we predict a sharp transition in the SMBH flaring diet beyond which all observable disruptions arise from evolved stars, accompanied by a dramatic cutoff in the overall tidal disruption flaring rate. Black holes less massive than this limiting mass scale will show observable flares from both main-sequence and evolved stars, with giants contributing up to 10% of the event rate. The relative fractions of stars disrupted at different evolutionary states can constrain the properties and distributions of stars in galactic nuclei other than our own.

  5. Cycloidal Wave Energy Converter

    SciTech Connect

    Stefan G. Siegel, Ph.D.

    2012-11-30

    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

  6. Impurity quantum phase transition in a current-carryingd-wave...

    Office of Scientific and Technical Information (OSTI)

    Sponsoring Org: USDOE Country of Publication: United States Language: English Word Cloud More Like This Free Publicly Accessible Full Text Publisher's Accepted Manuscript at...

  7. MHK ISDB/Instruments/Nortek Acoustic Wave and Current Meter ...

    OpenEI (Open Energy Information) [EERE & EIA]

    operation in tough underwater environments. Plastic and titanium parts avoid corrosion. The AWAC is available in three transmit frequencies for operational ranges spanning...

  8. Fast wave evanescence in filamentary boundary plasmas

    SciTech Connect

    Myra, J. R.

    2014-02-15

    Radio frequency waves for heating and current drive of plasmas in tokamaks and other magnetic confinement devices must first traverse the scrape-off-layer (SOL) before they can be put to their intended use. The SOL plasma is strongly turbulent and intermittent in space and time. These turbulent properties of the SOL, which are not routinely taken into account in wave propagation codes, can have an important effect on the coupling of waves through an evanescent SOL or edge plasma region. The effective scale length for fast wave (FW) evanescence in the presence of short-scale field-aligned filamentary plasma turbulence is addressed in this paper. It is shown that although the FW wavelength or evanescent scale length is long compared with the dimensions of the turbulence, the FW does not simply average over the turbulent density; rather, the average is over the exponentiation rate. Implications for practical situations are discussed.

  9. RADIATION WAVE DETECTION

    DOEpatents

    Wouters, L.F.

    1960-08-30

    Radiation waves can be detected by simultaneously measuring radiation- wave intensities at a plurality of space-distributed points and producing therefrom a plot of the wave intensity as a function of time. To this end. a detector system is provided which includes a plurality of nuclear radiation intensity detectors spaced at equal radial increments of distance from a source of nuclear radiation. Means are provided to simultaneously sensitize the detectors at the instant a wave of radiation traverses their positions. the detectors producing electrical pulses indicative of wave intensity. The system further includes means for delaying the pulses from the detectors by amounts proportional to the distance of the detectors from the source to provide an indication of radiation-wave intensity as a function of time.

  10. NREL Uses Computing Power to Investigate Tidal Power (Fact Sheet)

    SciTech Connect

    Not Available

    2012-10-01

    Until now, wind turbine controls that reduce the impacts of wind gusts and turbulence were always reactive - responding to the wind rather than anticipating it. But with today's laser-based sensors that measure wind speed ahead of the turbine, researchers at the National Renewable Energy Laboratory (NREL) and their industry partners are developing more intelligent controls. The world's first field tests of these controls are currently underway at the National Wind Technology Center (NWTC) at NREL, with plans for future commercialization.

  11. ocean wave energy

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    wave energy - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power Energy ...

  12. wave energy converter

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    ... Updates and Meeting Read More Permalink Advanced Controls of Wave Energy Converters May Increase Power Capture Up to 330% Computational Modeling & Simulation, Energy, News, ...

  13. Energy current imaging method for time reversal in elastic media

    SciTech Connect

    Anderson, Brian E; Ulrich, Timothy J; Le Bas, Pierre - Yves A; Larmat, Carene; Johnson, Paul A; Guyer, Robert A; Griffa, Michele

    2009-01-01

    An energy current imaging method is presented for use in locating sources of wave energy during the back propagation stage of the time reversal process. During the back propagation phase of an ideal time reversal experiment, wave energy coalesces from all angles of incidence to recreate the source event; after the recreation, wave energy diverges in every direction. An energy current imaging method based on this convergence/divergence behavior has been developed. The energy current imaging method yields a smaller spatial distribution for source reconstruction than is possible with traditional energy imaging methods.

  14. Residence Times of Juvenile Salmon and Steelhead in Off-Channel Tidal Freshwater Habitats, Columbia River, USA

    SciTech Connect

    Johnson, Gary E.; Ploskey, Gene R.; Sather, Nichole K.; Teel, D. J.

    2015-05-01

    We estimated seasonal residence times of acoustic-tagged juvenile salmonids in off-channel, tidal freshwater habitats of the Columbia River near the Sandy River delta (rkm 198; 2007, 2008, 2010, and 2011) and Cottonwood Island (rkm 112; 2012).

  15. IS THERE AN INTERMEDIATE MASSIVE BLACK HOLE IN THE GALACTIC CENTER: IMPRINTS ON THE STELLAR TIDAL-DISRUPTION RATE

    SciTech Connect

    Chen, Xian; Liu, F. K. E-mail: fkliu@pku.edu.cn

    2013-01-10

    It has been suggested that an intermediate-massive black hole (IMBH) with mass 10{sup 3-5} M {sub Sun} could fall into the galactic center (GC) and form a massive black hole binary (MBHB) with the central supermassive black hole, but current observations are not sensitive to constrain all mass and distance ranges. Motivated by the recent discovery that MBHBs could enhance the rate of tidal-disruption events (TDEs) of stellar objects, we investigate the prospect of using stellar-disruption rate to probe IMBHs in the GC. We incorporated the perturbation by an IMBH into the loss-cone theory and calculated the stellar-disruption rates in the GC. We found that an IMBH heavier than 2000 M {sub Sun} could distinguishably enhance the stellar-disruption rate. By comparing observations of Sgr A* with the fall-back model for stellar debris, we suggested that the TDE rate in our Galaxy should not significantly exceed 0.002 yr{sup -1}, therefore a fraction of the parameter space for the IMBH, concentrating at the high-mass end, can already be excluded. To derive constraint in the remaining parameter space, it is crucial to observationally confirm or reject the stellar-disruption rate between 10{sup -4} and 10{sup -2} yr{sup -1}, and we discussed possible strategies to make such measurements.

  16. Tidal disruptions in circumbinary disks. II. Observational signatures in the reverberation spectra

    SciTech Connect

    Brem, P.; Amaro-Seoane, P.; Cuadra, J.; Komossa, S.

    2014-09-10

    Supermassive binary black holes (SMBBHs) with sub-pc separations form in the course of galaxy mergers, if both galaxies harbor massive black holes. Clear observational evidence for them however still eludes us. We propose a novel method of identifying these systems by means of reverberation mapping their circumbinary disk after a tidal disruption event has ionized it. The tidal disruption of a star at the secondary leads to strong asymmetries in the disk response. We model the shape of the velocity-delay maps for various toy disk models and more realistic gas distributions obtained by smoothed particle hydrodynamics simulations. The emissivity of the ionized disk is calculated with Cloudy. We find peculiar asymmetries in the maps for off center ionizing sources that may help us constrain geometrical parameters of a circumbinary disk such as semimajor axis and orbital phase of the secondary, as well as help strengthen the observational evidence for sub-parsec SMBBHs as such.

  17. LINE-PROFILE VARIABILITY FROM TIDAL FLOWS IN ALPHA VIRGINIS (SPICA)

    SciTech Connect

    Harrington, David; Kuhn, Jeffrey; Koenigsberger, Gloria; Moreno, Edmundo E-mail: kuhn@ifa.hawaii.ed

    2009-10-10

    We present the results of high precision, high-resolution (R approx 68,000) optical observations of the short-period (4 days) eccentric binary system Alpha Virginis (Spica) showing the photospheric line-profile variability that in this system can be attributed to non-radial pulsations driven by tidal effects. Although scant in orbital-phase coverage, the data provide signal-to-noise ratio > 2000 line profiles at full spectral resolution in the wavelength range DELTAlambda4000-8500 A, allowing a detailed study of the night-to-night variability as well as changes that occur on approx2 hr timescale. Using an ab initio theoretical calculation, we show that the line-profile variability can arise as a natural consequence of surface flows that are induced by the tidal interaction.

  18. TRENDS IN DWARF EARLY-TYPE KINEMATICS WITH CLUSTER-CENTRIC RADIUS DRIVEN BY TIDAL STIRRING

    SciTech Connect

    Benson, A. J.; Toloba, E.; Simon, J. D.; Mayer, L.; Guhathakurta, P.

    2015-02-01

    We model the dynamics of dwarf early-type galaxies in the Virgo cluster when subject to a variety of environmental processes. We focus on how these processes imprint trends in the dynamical state (rotational versus pressure support as measured by the λ{sub Re/2}{sup ∗} statistic) with projected distance from the cluster center, and compare these results to observational estimates. We find a large scatter in the gradient of λ{sub Re/2}{sup ∗} with projected radius. A statistical analysis shows that models with no environmental effects produce gradients as steep as those observed in none of the 100 cluster realizations we consider, while in a model incorporating tidal stirring by the cluster potential 34% of realizations produce gradients as steep as that observed. Our results suggest that tidal stirring may be the cause of the observed radial dependence of dwarf early-type dynamics in galaxy clusters.

  19. Theory of current-drive in plasmas

    SciTech Connect

    Fisch, N.J.

    1986-12-01

    The continuous operation of a tokamak fusion reactor requires, among other things, a means of providing continuous toroidal current. Such operation is preferred to the conventional pulsed operation, where the plasma current is induced by a time-varying magnetic field. A variety of methods has been proposed to provide continuous current, including methods which utilize particle beams or radio frequency waves in any of several frequency regimes. Currents as large as half a mega-amp have now been produced in the laboratory by such means, and experimentation in these techniques has now involved major tokamak facilities worldwide.

  20. MHK Technologies/The DEXAWAVE wave energy converter | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    Scale Test *At present our 1 to 5 scale model is working the waters outside the Danish port of Hanstholm collecting valuable data about the waves and currents that are constantly...

  1. Broadband Acoustic Environment at a Tidal Energy Site in Puget Sound

    SciTech Connect

    Xu, Jinshan; Deng, Zhiqun; Martinez, Jayson J.; Carlson, Thomas J.; Myers, Joshua R.; Weiland, Mark A.

    2012-04-04

    Admiralty Inlet has been selected as a potential tidal energy site. It is located near shipping lanes, is a highly variable acoustic environment, and is frequented by the endangered southern resident killer whale (SRKW). Resolving environmental impacts is the first step to receiving approval to deploy tidal turbines. Several monitoring technologies are being considered to determine the presence of SRKW near the turbines. Broadband noise level measurements are critical for determining design and operational specifications of these technologies. Acoustic environment data at the proposed site was acquired at different depths using a cabled vertical line array from three different cruises during high tidal period in February, May, and June 2011. The ambient noise level decreases approximately 25 dB re 1 μPa per octave from frequency ranges of 1 kHz to 70 kHz, and increases approximately 20 dB re 1 μPa per octave for the frequency from 70 kHz to 200 kHz. The difference of noise pressure levels in different months varies from 10 to 30 dB re 1 μPa for the frequency range below 70 kHz. Commercial shipping and ferry vessel traffic were found to be the most significant contributors to sound pressure levels for the frequency range from 100 Hz to 70 kHz, and the variation could be as high as 30 dB re 1 μPa. These noise level measurements provide the basic information for designing and evaluating both active and passive monitoring systems proposed for deploying and operating for tidal power generation alert system.

  2. Superconducting fault current controller/current controller

    DOEpatents

    Cha, Yung S.

    2004-06-15

    A superconducting fault current controller/current controller employs a superconducting-shielded core reactor (SSCR) with a variable impedance in a secondary circuit to control current in a primary circuit such as an electrical distribution system. In a second embodiment, a variable current source is employed in a secondary circuit of an SSCR to control current in the primary circuit. In a third embodiment, both a variable impedance in one secondary circuit and a variable current source in a second circuit of an SSCR are employed for separate and independent control of current in the primary circuit.

  3. Wave-wave interactions in solar type III radio bursts

    SciTech Connect

    Thejappa, G.; MacDowall, R. J.

    2014-02-11

    The high time resolution observations from the STEREO/WAVES experiment show that in type III radio bursts, the Langmuir waves often occur as localized magnetic field aligned coherent wave packets with durations of a few ms and with peak intensities well exceeding the strong turbulence thresholds. Some of these wave packets show spectral signatures of beam-resonant Langmuir waves, down- and up-shifted sidebands, and ion sound waves, with frequencies, wave numbers, and tricoherences satisfying the resonance conditions of the oscillating two stream instability (four wave interaction). The spectra of a few of these wave packets also contain peaks at f{sub pe}, 2f{sub pe} and 3 f{sub pe} (f{sub pe} is the electron plasma frequency), with frequencies, wave numbers and bicoherences (computed using the wavelet based bispectral analysis techniques) satisfying the resonance conditions of three wave interactions: (1) excitation of second harmonic electromagnetic waves as a result of coalescence of two oppositely propagating Langmuir waves, and (2) excitation of third harmonic electromagnetic waves as a result of coalescence of Langmuir waves with second harmonic electromagnetic waves. The implication of these findings is that the strong turbulence processes play major roles in beam stabilization as well as conversion of Langmuir waves into escaping radiation in type III radio bursts.

  4. RF wave propagation and scattering in turbulent tokamak plasmas

    SciTech Connect

    Horton, W. Michoski, C.; Peysson, Y.; Decker, J.

    2015-12-10

    Drift wave turbulence driven by the steep electron and ion temperature gradients in H-mode divertor tokamaks produce scattering of the RF waves used for heating and current drive. The X-ray emission spectra produced by the fast electrons require the turbulence broaden RF wave spectrum. Both the 5 GHz Lower Hybrid waves and the 170 GHz electron cyclotron [EC] RF waves experience scattering and diffraction by the electron density fluctuations. With strong LHCD there are bifurcations in the coupled turbulent transport dynamics giving improved steady-state confinement states. The stochastic scattering of the RF rays makes the prediction of the distribution of the rays and the associated particle heating a statistical problem. Thus, we introduce a Fokker-Planck equation for the probably density of the RF rays. The general frame work of the coupled system of coupled high frequency current driving rays with the low-frequency turbulent transport determines the profiles of the plasma density and temperatures.

  5. Shock wave convergence in water with parabolic wall boundaries

    SciTech Connect

    Yanuka, D.; Shafer, D.; Krasik, Ya.

    2015-04-28

    The convergence of shock waves in water, where the cross section of the boundaries between which the shock wave propagates is either straight or parabolic, was studied. The shock wave was generated by underwater electrical explosions of planar Cu wire arrays using a high-current generator with a peak output current of ?45?kA and rise time of ?80?ns. The boundaries of the walls between which the shock wave propagates were symmetric along the z axis, which is defined by the direction of the exploding wires. It was shown that with walls having a parabolic cross section, the shock waves converge faster and the pressure in the vicinity of the line of convergence, calculated by two-dimensional hydrodynamic simulations coupled with the equations of state of water and copper, is also larger.

  6. Lattice Waves, Spin Waves, and Neutron Scattering

    DOE R&D Accomplishments

    Brockhouse, Bertram N.

    1962-03-01

    Use of neutron inelastic scattering to study the forces between atoms in solids is treated. One-phonon processes and lattice vibrations are discussed, and experiments that verified the existence of the quantum of lattice vibrations, the phonon, are reviewed. Dispersion curves, phonon frequencies and absorption, and models for dispersion calculations are discussed. Experiments on the crystal dynamics of metals are examined. Dispersion curves are presented and analyzed; theory of lattice dynamics is considered; effects of Fermi surfaces on dispersion curves; electron-phonon interactions, electronic structure influence on lattice vibrations, and phonon lifetimes are explored. The dispersion relation of spin waves in crystals and experiments in which dispersion curves for spin waves in Co-Fe alloy and magnons in magnetite were obtained and the reality of the magnon was demonstrated are discussed. (D.C.W)

  7. Traveling-wave photodetector

    DOEpatents

    Hietala, Vincent M.; Vawter, Gregory A.

    1993-01-01

    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.

  8. Traveling-wave photodetector

    DOEpatents

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

    1993-12-14

    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.

  9. WindWaveFloat

    SciTech Connect

    Weinstein, Alla

    2011-11-01

    Presentation from the 2011 Water Peer Review includes in which principal investigator Alla Weinstein discusses project progress in development of a floating offshore wind structure - the WindFloat - and incorporation therin of a Spherical Wave Energy Device.

  10. Gravitational Waves Community Lecture

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Gravitational Waves Community Lecture Gravitational Waves Community Lecture WHEN: Sep 19, 2016 7:30 PM - 8:30 PM WHERE: Grand Ballroom at the Eldorado Hotel 309 W San Francisco St Santa Fe, New Mexico 87501 USA (505) 988-4455 SPEAKER: Gabriela Gonzalez CONTACT: Linda Anderman (505) 665-9196 CATEGORY: Bradbury INTERNAL: Calendar Login Event Description Sponsored by Los Alamos National Laboratory, University of New Mexico, St. John's College and Santa Fe Community College The Los Alamos National

  11. Wave Propagation Program

    Energy Science and Technology Software Center

    2007-01-08

    WPP is a massively parallel, 3D, C++, finite-difference elastodynamic wave propagation code. Typical applications for wave propagation with WPP include: evaluation of seismic event scenarios and damage from earthquakes, non-destructive evaluation of materials, underground facility detection, oil and gas exploration, predicting the electro-magnetic fields in accelerators, and acoustic noise generation. For more information, see User’s Manual [1].

  12. Gravitational waves from gamma-ray pulsar glitches

    SciTech Connect

    Stopnitzky, Elan; Profumo, Stefano

    2014-06-01

    We use data from pulsar gamma-ray glitches recorded by the Fermi Large Area Telescope as input to theoretical models of gravitational wave signals the glitches might generate. We find that the typical peak amplitude of the gravity wave signal from gamma-ray pulsar glitches lies between 10{sup 23} and 10{sup 35} in dimensionless units, with peak frequencies in the range of 1 to 1000 Hz, depending on the model. We estimate the signal-to-noise ratio (S/N) for all gamma-ray glitches, and discuss detectability with current gravity wave detectors. Our results indicate that the strongest predicted signals are potentially within reach of current detectors, and that pulsar gamma-ray glitches are promising targets for gravity wave searches by current and next-generation detectors.

  13. Commercial Current Promotions

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    New Commercial Program Development Commercial Current Promotions Industrial Federal Agriculture This page features all current special promotions for commercial programs....

  14. System and method for generating current by selective electron heating

    DOEpatents

    Fisch, Nathaniel J.; Boozer, Allen H.

    1984-01-01

    A system for the generation of toroidal current in a plasma which is prepared in a toroidal magnetic field. The system utilizes the injection of high-frequency waves into the plasma by means of waveguides. The wave frequency and polarization are chosen such that when the waveguides are tilted in a predetermined fashion, the wave energy is absorbed preferentially by electrons traveling in one toroidal direction. The absorption of energy in this manner produces a toroidal electric current even when the injected waves themselves do not have substantial toroidal momentum. This current can be continuously maintained at modest cost in power and may be used to confine the plasma. The system can operate efficiently on fusion grade tokamak plasmas.

  15. PROBING THE STRUCTURE OF THE OUTFLOW IN THE TIDAL DISRUPTION FLARE Sw J1644+57 WITH LONG-TERM RADIO EMISSION

    SciTech Connect

    Cao Di; Wang Xiangyu

    2012-12-20

    The recently discovered high-energy transient Sw J1644+57 is thought to arise from the tidal disruption of a passing star by a dormant massive black hole. The long-term, bright radio emission of Sw J1644+57 is believed to result from the synchrotron emission of the blast wave produced by an outflow expanding into the surrounding medium. Using the detailed multi-epoch radio spectral data, we are able to determine the total number of radiating electrons in the outflow at different times, and further the evolution of the cross section of the outflow with time. We find that the outflow gradually transits from a conical jet to a cylindrical one at later times. The transition may be due to collimation of the outflow by the pressure of the shocked jet cocoon that forms while the outflow is propagating in the ambient medium. Since cylindrical jets usually exist in active galactic nuclei (AGNs) and extragalactic jets, this may provide independent evidence that Sw J1644+57 signals the onset of an AGN.

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

    SciTech Connect

    Lee, Frank M.; Morrison, P. J. [Physics Department and Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 787121192 (United States)] [Physics Department and Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 787121192 (United States); Paoletti, M. S.; Swinney, Harry L. [Physics Department, The University of Texas at Austin, Austin, Texas 787121192 (United States)] [Physics Department, The University of Texas at Austin, Austin, Texas 787121192 (United States)

    2014-04-15

    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.

  17. Environmental implications of wave energy proposals for the Outer Hebrides and Moray Firth

    SciTech Connect

    Probert, P.K.; Mitchell, R.

    1983-01-01

    The Nature Conservancy Council has carried out appraisals for the Department of Energy of environmental implications of siting full-scale floating or seabed-mounted wave energy converters off the west coast of the Outer Hebrides and full-scale floating devices off the Moray Firth. Converters have a variety of effects on the hydraulic environment, most noticeably by modifying the local wave climate. A decrease in incident wave energy influences shores and shallow subtidal areas and results in changes in the density and species of organisms they support. Extensive shell-sand beaches occur along the west coast of the Uists but although wave activity and wave steepness would be reduced, accretion on these beaches might be limited by the availability of sediment. Fixed converters off the Hebrides would have more pronounced environmental impacts than offshore floating devices, mainly through their greater sheltering effect, the possibly stronger tidal flows generated between devices and shores, and the need to site fixed converters in the kelp zone. Devices would represent a new habitat for colonisation by attached algae and invertebrates and would probably attract fish, seabirds and seals. Seabed-mounted devices, once no longer operational, would become artificial reefs if left in place. Device noise might affect communication and navigation systems of fish and marine mammals. The navigational hazard to shipping posed by converters would be likely to increase the risk of severe oil pollution incidents in areas that are populated by internationally important numbers of seabirds.

  18. Efficient transformer for electromagnetic waves

    DOEpatents

    Miller, R.B.

    A transformer structure for efficient transfer of electromagnetic energy from a transmission line to an unmatched load provides voltage multiplication and current division by a predetermined constant. Impedance levels are transformed by the square of that constant. The structure includes a wave splitter, connected to an input transmission device and to a plurality of output transmission devices. The output transmission devices are effectively connected in parallel to the input transmission device. The output transmission devices are effectively series connected to provide energy to a load. The transformer structure is particularly effective in increasing efficiency of energy transfer through an inverting convolute structure by capturing and transferring energy losses from the inverter to the load.

  19. Standing wave compressor

    DOEpatents

    Lucas, Timothy S.

    1991-01-01

    A compressor for compression-evaporation cooling systems, which requires no moving parts. A gaseous refrigerant inside a chamber is acoustically compressed and conveyed by means of a standing acoustic wave which is set up in the gaseous refrigerant. This standing acoustic wave can be driven either by a transducer, or by direct exposure of the gas to microwave and infrared sources, including solar energy. Input and output ports arranged along the chamber provide for the intake and discharge of the gaseous refrigerant. These ports can be provided with optional valve arrangements, so as to increase the compressor's pressure differential. The performance of the compressor in either of its transducer or electromagnetically driven configurations, can be optimized by a controlling circuit. This controlling circuit holds the wavelength of the standing acoustical wave constant, by changing the driving frequency in response to varying operating conditions.

  20. Piezoelectric wave motor

    DOEpatents

    Yerganian, Simon Scott

    2003-02-11

    A piezoelectric motor having a stator in which piezoelectric elements are contained in slots formed in the stator transverse to the desired wave motion. When an electric field is imposed on the elements, deformation of the elements imposes a force perpendicular to the sides of the slot, deforming the stator. Appropriate frequency and phase-shifting of the electric field will produce a wave in the stator and motion in a rotor. In a preferred aspect, the piezoelectric elements are configured so that deformation of the elements in the direction of an imposed electric field, generally referred to as the d.sub.33 direction, is utilized to produce wave motion in the stator. In a further aspect, the elements are compressed into the slots so as to minimize tensile stresses on the elements in use.

  1. Piezoelectric wave motor

    DOEpatents

    Yerganian, Simon Scott

    2001-07-17

    A piezoelectric motor having a stator in which piezoelectric elements are contained in slots formed in the stator transverse to the desired wave motion. When an electric field is imposed on the elements, deformation of the elements imposes a force perpendicular to the sides of the slot, deforming the stator. Appropriate frequency and phase shifting of the electric field will produce a wave in the stator and motion in a rotor. In a preferred aspect, the piezoelectric elements are configured so that deformation of the elements in direction of an imposed electric field, generally referred to as the d.sub.33 direction, is utilized to produce wave motion in the stator. In a further aspect, the elements are compressed into the slots so as to minimize tensile stresses on the elements in use.

  2. TIMING OF SHOCK WAVES

    DOEpatents

    Tuck, J.L.

    1955-03-01

    This patent relates to means for ascertaining the instant of arrival of a shock wave in an exploslve charge and apparatus utilizing this means to coordinate the timing of two operations involving a short lnterval of time. A pair of spaced electrodes are inserted along the line of an explosive train with a voltage applied there-across which is insufficient to cause discharge. When it is desired to initiate operation of a device at the time the explosive shock wave reaches a particular point on the explosive line, the device having an inherent time delay, the electrodes are located ahead of the point such that the ionization of the area between the electrodes caused by the traveling explosive shock wave sends a signal to initiate operation of the device to cause it to operate at the proper time. The operated device may be photographic equipment consisting of an x-ray illuminating tube.

  3. Current to Current Corporation | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Zip: 1803 Sector: Ocean Product: Developing a technology which generates power from ocean currents : Submersible Power Generators (SPG). Coordinates: 44.446275,...

  4. Adaptive multiconfigurational wave functions

    SciTech Connect

    Evangelista, Francesco A.

    2014-03-28

    A method is suggested to build simple multiconfigurational wave functions specified uniquely by an energy cutoff ?. These are constructed from a model space containing determinants with energy relative to that of the most stable determinant no greater than ?. The resulting ?-CI wave function is adaptive, being able to represent both single-reference and multireference electronic states. We also consider a more compact wave function parameterization (?+SD-CI), which is based on a small ?-CI reference and adds a selection of all the singly and doubly excited determinants generated from it. We report two heuristic algorithms to build ?-CI wave functions. The first is based on an approximate prescreening of the full configuration interaction space, while the second performs a breadth-first search coupled with pruning. The ?-CI and ?+SD-CI approaches are used to compute the dissociation curve of N{sub 2} and the potential energy curves for the first three singlet states of C{sub 2}. Special attention is paid to the issue of energy discontinuities caused by changes in the size of the ?-CI wave function along the potential energy curve. This problem is shown to be solvable by smoothing the matrix elements of the Hamiltonian. Our last example, involving the Cu{sub 2}O{sub 2}{sup 2+} core, illustrates an alternative use of the ?-CI method: as a tool to both estimate the multireference character of a wave function and to create a compact model space to be used in subsequent high-level multireference coupled cluster computations.

  5. Explosive plane-wave lens

    DOEpatents

    Marsh, S.P.

    1987-03-12

    An explosive plane-wave air lens which enables a spherical wave form to be converted to a planar wave without the need to specially machine or shape explosive materials is described. A disc-shaped impactor having a greater thickness at its center than around its periphery is used to convert the spherical wave into a plane wave. When the wave reaches the impactor, the center of the impactor moves first because the spherical wave reaches the center of the impactor first. The wave strikes the impactor later in time as one moves radially along the impactor. Because the impactor is thinner as one moves radially outward, the velocity of the impactor is greater at the periphery than at the center. An acceptor explosive is positioned so that the impactor strikes the acceptor simultaneously. Consequently, a plane detonation wave is propagated through the acceptor explosive. 3 figs., 3 tabs.

  6. Explosive plane-wave lens

    DOEpatents

    Marsh, Stanley P.

    1988-01-01

    An explosive plane-wave air lens which enables a spherical wave form to be converted to a planar wave without the need to specially machine or shape explosive materials is described. A disc-shaped impactor having a greater thickness at its center than around its periphery is used to convert the spherical wave into a plane wave. When the wave reaches the impactor, the center of the impactor moves first because the spherical wave reaches the center of the impactor first. The wave strikes the impactor later in time as one moves radially along the impactor. Because the impactor is thinner as one moves radially outward, the velocity of the impactor is greater at the periphery than at the center. An acceptor explosive is positioned so that the impactor strikes the acceptor simultaneously. Consequently, a plane detonation wave is propagated through the acceptor explosive.

  7. Explosive plane-wave lens

    DOEpatents

    Marsh, S.P.

    1988-03-08

    An explosive plane-wave air lens which enables a spherical wave form to be converted to a planar wave without the need to specially machine or shape explosive materials is described. A disc-shaped impactor having a greater thickness at its center than around its periphery is used to convert the spherical wave into a plane wave. When the wave reaches the impactor, the center of the impactor moves first because the spherical wave reaches the center of the impactor first. The wave strikes the impactor later in time as one moves radially along the impactor. Because the impactor is thinner as one moves radially outward, the velocity of the impactor is greater at the periphery than at the center. An acceptor explosive is positioned so that the impactor strikes the acceptor simultaneously. Consequently, a plane detonation wave is propagated through the acceptor explosive. 4 figs.

  8. Assessment of acreage and vegetation change in Florida`s Big Bend tidal wetlands using satellite imagery

    SciTech Connect

    Raabe, E.A.; Stumpf, R.P.

    1997-06-01

    Fluctuations in sea level and impending development on the west coast of Florida have aroused concern for the relatively pristine tidal marshes of the Big Bend. Landsat Thematic Mapper (TM) images for 1986 and 1995 are processed and evaluated for signs of change. The images cover 250 km of Florida`s Big Bend Gulf Coast, encompassing 160,000 acres of tidal marshes. Change is detected using the normalized difference vegetation index (NDVI) and land cover classification. The imagery shows negligible net loss or gain in the marsh over the 9-year period. However, regional changes in biomass are apparent and are due to natural disturbances such as low winter temperatures, fire, storm surge, and the conversion of forest to marsh. Within the marsh, the most prominent changes in NDVI and in land cover result from the recovery of mangroves from freezes, a decline of transitional upland vegetation, and susceptibility of the marsh edge and interior to variations in tidal flooding.

  9. A Synthesis of Environmental and Plant Community Data for Tidal Wetland Restoration Planning in the Lower Columbia River and Estuary

    SciTech Connect

    Diefenderfer, Heida L.; Borde, Amy B.; Cullinan, Valerie I.

    2013-12-01

    This report reanalyzes and synthesizes previously existing environmental and plant community data collected by PNNL at 55 tidal wetlands and 3 newly restored sites in the lower Columbia River and estuary (LCRE) between 2005 and 2011. Whereas data were originally collected for various research or monitoring objectives of five studies, the intent of this report is to provide only information that will have direct utility in planning tidal wetland restoration projects. Therefore, for this report, all tidal wetland data on plants and the physical environment, which were originally developed and reported by separate studies, were tabulated and reanalyzed as a whole. The geographic scope of the data collected in this report is from Bonneville Lock and Dam to the mouth of the Columbia River

  10. RADIATION WAVE DETECTOR

    DOEpatents

    Wouters, L.F.

    1958-10-28

    The detection of the shape and amplitude of a radiation wave is discussed, particularly an apparatus for automatically indicating at spaced lntervals of time the radiation intensity at a flxed point as a measure of a radiation wave passing the point. The apparatus utilizes a number of photomultiplier tubes surrounding a scintillation type detector, For obtainlng time spaced signals proportional to radiation at predetermined intervals the photolnultiplier tubes are actuated ln sequence following detector incidence of a predetermined radiation level by electronic means. The time spaced signals so produced are then separately amplified and relayed to recording means.

  11. Quantum positron acoustic waves

    SciTech Connect

    Metref, Hassina; Tribeche, Mouloud

    2014-12-15

    Nonlinear quantum positron-acoustic (QPA) waves are investigated for the first time, within the theoretical framework of the quantum hydrodynamic model. In the small but finite amplitude limit, both deformed Korteweg-de Vries and generalized Korteweg-de Vries equations governing, respectively, the dynamics of QPA solitary waves and double-layers are derived. Moreover, a full finite amplitude analysis is undertaken, and a numerical integration of the obtained highly nonlinear equations is carried out. The results complement our previously published results on this problem.

  12. EERE Success Story-Measuring the Impact of Tidal Power Installations...

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Program is committed to developing and deploying a portfolio of innovative technologies for clean, domestic power generation from resources such as hydropower, waves, and tides. ...

  13. Tidal sampler

    DOEpatents

    Hayes, David W.

    1978-01-01

    An apparatus for pumping a sample of water or other liquid that uses the energy generated from the rise and fall of the liquid level to force a sample of the liquid into a collection vessel. A suction vessel and booster vessel with interconnecting tubing and check valves are responsive to an oscillating liquid level to pump a portion of said liquid into a collection vessel.

  14. Superconducting submillimeter and millimeter wave detectors

    SciTech Connect

    Nahum, M.

    1992-10-20

    The series of projects described in this dissertation was stimulated by the discovery of high temperature superconductivity. Our goal was to develop useful applications which would be competitive with the current state of technology. The high-[Tc] microbolometer was developed into the most sensitive direct detector of millimeter waves, when operated at liquid nitrogen temperatures. The thermal boundary resistance of thin YBa[sub 2]Cu[sub 3]0[sub 7-[delta

  15. Wave induced density modification in RF sheaths and close to wave launchers

    SciTech Connect

    Van Eester, D.; Lu, Ling-Feng

    2015-12-10

    With the return to full metal walls - a necessary step towards viable fusion machines - and due to the high power densities of current-day ICRH (Ion Cyclotron Resonance Heating) or RF (radio frequency) antennas, there is ample renewed interest in exploring the reasons for wave-induced sputtering and formation of hot spots. Moreover, there is experimental evidence on various machines that RF waves influence the density profile close to the wave launchers so that waves indirectly influence their own coupling efficiency. The present study presents a return to first principles and describes the wave-particle interaction using a 2-time scale model involving the equation of motion, the continuity equation and the wave equation on each of the time scales. Through the changing density pattern, the fast time scale dynamics is affected by the slow time scale events. In turn, the slow time scale density and flows are modified by the presence of the RF waves through quasilinear terms. Although finite zero order flows are identified, the usual cold plasma dielectric tensor - ignoring such flows - is adopted as a first approximation to describe the wave response to the RF driver. The resulting set of equations is composed of linear and nonlinear equations and is tackled in 1D in the present paper. Whereas the former can be solved using standard numerical techniques, the latter require special handling. At the price of multiple iterations, a simple ’derivative switch-on’ procedure allows to reformulate the nonlinear problem as a sequence of linear problems. Analytical expressions allow a first crude assessment - revealing that the ponderomotive potential plays a role similar to that of the electrostatic potential arising from charge separation - but numerical implementation is required to get a feeling of the full dynamics. A few tentative examples are provided to illustrate the phenomena involved.

  16. GRB060218 AS A TIDAL DISRUPTION OF A WHITE DWARF BY AN INTERMEDIATE-MASS BLACK HOLE

    SciTech Connect

    Shcherbakov, Roman V.; Reynolds, Christopher S.; Pe'er, Asaf; Haas, Roland; Bode, Tanja; Laguna, Pablo

    2013-06-01

    The highly unusual pair of a gamma-ray burst (GRB) GRB060218 and an associated supernova, SN2006aj, has puzzled theorists for years. A supernova shock breakout and a jet from a newborn stellar mass compact object have been proposed to explain this pair's multiwavelength signature. Alternatively, we propose that the source is naturally explained by another channel: the tidal disruption of a white dwarf (WD) by an intermediate-mass black hole (IMBH). This tidal disruption is accompanied by a tidal pinching, which leads to the ignition of a WD and a supernova. Some debris falls back onto the IMBH, forms a disk, which quickly amplifies the magnetic field, and launches a jet. We successfully fit soft X-ray spectra with the Comptonized blackbody emission from a jet photosphere. The optical/UV emission is consistent with self-absorbed synchrotron emission from the expanding jet front. The temporal dependence of the accretion rate M-dot (t) in a tidal disruption provides a good fit to the soft X-ray light curve. The IMBH mass is found to be about 10{sup 4} M{sub Sun} in three independent estimates: (1) fitting the tidal disruption M-dot (t) to the soft X-ray light curve, (2) computing the jet base radius in a jet photospheric emission model, and (3) inferring the mass of the central black hole based on the host dwarf galaxy's stellar mass. The position of the supernova is consistent with the center of the host galaxy, while the low supernova ejecta mass is consistent with that of a WD. The high expected rate of tidal disruptions in dwarf galaxies is consistent with one source observed by the Swift satellite over several years at a distance of 150 Mpc measured for GRB060218. Encounters with WDs provide much fuel for the growth of IMBHs.

  17. Hydraulic Geometry and Microtopography of Tidal Freshwater Forested Wetlands and Implications for Restoration, Columbia River, U.S.A.

    SciTech Connect

    Diefenderfer, Heida L.; Coleman, Andre M.; Borde, Amy B.; Sinks, Ian A.

    2008-01-01

    The hydrologic reconnection of tidal channels, riverine floodplains, and main stem channels are among responses by ecological restoration practitioners to the increasing fragmentation and land conversion occurring in coastal and riparian zones. Design standards and monitoring of such ecological restoration depend upon the characterization of reference sites that vary within and among regions. Few locales, such as the 235 km tidal portion of the Columbia River on the West Coast U.S.A., remain in which the reference conditions and restoration responses of tidal freshwater forested wetlands on temperate zone large river floodplains can be compared. This study developed hydraulic geometry relationships for Picea sitchensis (Sitka spruce) dominated tidal forests (swamps) in the vicinity of Grays Bay on the Columbia River some 37 km from the Pacific Coast using field surveys and Light Detection and Ranging (LiDAR) data. Scaling relationships between catchment area and the parameters of channel cross-sectional area at outlet and total channel length were comparable to tidally influenced systems of San Francisco Bay and the United Kingdom. Dike breaching, culvert replacement, and tide gate replacement all affected channel cross-sectional geometry through changes in the frequency of over-marsh flows. Radiocarbon dating of buried wood provided evidence of changes in sedimentation rates associated with diking, and restoration trajectories may be confounded by historical subsidence behind dikes rendering topographical relationships with water level incomparable to reference conditions. At the same time, buried wood is influencing the development of channel morphology toward characteristics resembling reference conditions. Ecological restoration goals and practices in tidal forested wetland regions of large river floodplains should reflect the interactions of these controlling factors.

  18. A tidal disruption event in a nearby galaxy hosting an intermediate mass black hole

    SciTech Connect

    Donato, D.; Troja, E.; Pursimo, T.; Cheung, C. C.; Kutyrev, A.; Landt, H.; Butler, N. R.

    2014-02-01

    We report the serendipitous discovery of a bright point source flare in the Abell cluster A1795 with archival EUVE and Chandra observations. Assuming the EUVE emission is associated with the Chandra source, the X-ray 0.5-7 keV flux declined by a factor of ?2300 over a time span of 6 yr, following a power-law decay with index ?2.44 0.40. The Chandra data alone vary by a factor of ?20. The spectrum is well fit by a blackbody with a constant temperature of kT ? 0.09 keV (?10{sup 6} K). The flare is spatially coincident with the nuclear region of a faint, inactive galaxy with a photometric redshift consistent at the 1? level with the cluster (z = 0.062476). We argue that these properties are indicative of a tidal disruption of a star by a black hole (BH) with log (M {sub BH}/M {sub ?}) ? 5.5 0.5. If so, such a discovery indicates that tidal disruption flares may be used to probe BHs in the intermediate mass range, which are very difficult to study by other means.

  19. A STATISTICAL METHOD FOR MEASURING THE GALACTIC POTENTIAL AND TESTING GRAVITY WITH COLD TIDAL STREAMS

    SciTech Connect

    Penarrubia, Jorge; Walker, Matthew G.

    2012-11-20

    We introduce the Minimum Entropy Method, a simple statistical technique for constraining the Milky Way gravitational potential and simultaneously testing different gravity theories directly from 6D phase-space surveys and without adopting dynamical models. We demonstrate that orbital energy distributions that are separable (i.e., independent of position) have an associated entropy that increases under wrong assumptions about the gravitational potential and/or gravity theory. Of known objects, 'cold' tidal streams from low-mass progenitors follow orbital distributions that most nearly satisfy the condition of separability. Although the orbits of tidally stripped stars are perturbed by the progenitor's self-gravity, systematic variations of the energy distribution can be quantified in terms of the cross-entropy of individual tails, giving further sensitivity to theoretical biases in the host potential. The feasibility of using the Minimum Entropy Method to test a wide range of gravity theories is illustrated by evolving restricted N-body models in a Newtonian potential and examining the changes in entropy introduced by Dirac, MONDian, and f(R) gravity modifications.

  20. OBLIQUITIES OF HOT JUPITER HOST STARS: EVIDENCE FOR TIDAL INTERACTIONS AND PRIMORDIAL MISALIGNMENTS

    SciTech Connect

    Albrecht, Simon; Winn, Joshua N.; Johnson, John A.; Howard, Andrew W.; Marcy, Geoffrey W.; Butler, R. Paul; Arriagada, Pamela; Crane, Jeffrey D.; Shectman, Stephen A.; Thompson, Ian B.; Hirano, Teruyuki; Bakos, Gaspar; Hartman, Joel D.

    2012-09-20

    We provide evidence that the obliquities of stars with close-in giant planets were initially nearly random, and that the low obliquities that are often observed are a consequence of star-planet tidal interactions. The evidence is based on 14 new measurements of the Rossiter-McLaughlin effect (for the systems HAT-P-6, HAT-P-7, HAT-P-16, HAT-P-24, HAT-P-32, HAT-P-34, WASP-12, WASP-16, WASP-18, WASP-19, WASP-26, WASP-31, Gl 436, and Kepler-8), as well as a critical review of previous observations. The low-obliquity (well-aligned) systems are those for which the expected tidal timescale is short, and likewise the high-obliquity (misaligned and retrograde) systems are those for which the expected timescale is long. At face value, this finding indicates that the origin of hot Jupiters involves dynamical interactions like planet-planet interactions or the Kozai effect that tilt their orbits rather than inspiraling due to interaction with a protoplanetary disk. We discuss the status of this hypothesis and the observations that are needed for a more definitive conclusion.

  1. KOI-54: THE KEPLER DISCOVERY OF TIDALLY EXCITED PULSATIONS AND BRIGHTENINGS IN A HIGHLY ECCENTRIC BINARY

    SciTech Connect

    Welsh, William F.; Orosz, Jerome A.; Aerts, Conny; Zima, Wolfgang; Brown, Timothy M.; Brugamyer, Erik; Cochran, William D.; Gilliland, Ronald L.; Guzik, Joyce Ann; Kurtz, D. W.; Latham, David W.; Quinn, Samuel N.; Marcy, Geoffrey W.; Allen, Christopher; Bryson, Steve; Caldwell, Douglas A.; Howell, Steve B.; Gautier, Thomas N.

    2011-11-01

    Kepler observations of the star HD 187091 (KIC 8112039, hereafter KOI-54) revealed a remarkable light curve exhibiting sharp periodic brightening events every 41.8 days with a superimposed set of oscillations forming a beating pattern in phase with the brightenings. Spectroscopic observations revealed that this is a binary star with a highly eccentric orbit, e = 0.83. We are able to match the Kepler light curve and radial velocities with a nearly face-on (i = 5.{sup 0}5) binary star model in which the brightening events are caused by tidal distortion and irradiation of nearly identical A stars during their close periastron passage. The two dominant oscillations in the light curve, responsible for the beating pattern, have frequencies that are the 91st and 90th harmonic of the orbital frequency. The power spectrum of the light curve, after removing the binary star brightening component, reveals a large number of pulsations, 30 of which have a signal-to-noise ratio {approx}>7. Nearly all of these pulsations have frequencies that are either integer multiples of the orbital frequency or are tidally split multiples of the orbital frequency. This pattern of frequencies unambiguously establishes the pulsations as resonances between the dynamic tides at periastron and the free oscillation modes of one or both of the stars. KOI-54 is only the fourth star to show such a phenomenon and is by far the richest in terms of excited modes.

  2. Milky Way mass and potential recovery using tidal streams in a realistic halo

    SciTech Connect

    Bonaca, Ana; Geha, Marla; Kpper, Andreas H. W.; Johnston, Kathryn V.; Diemand, Jrg; Hogg, David W.

    2014-11-01

    We present a new method for determining the Galactic gravitational potential based on forward modeling of tidal stellar streams. We use this method to test the performance of smooth and static analytic potentials in representing realistic dark matter halos, which have substructure and are continually evolving by accretion. Our FAST-FORWARD method uses a Markov Chain Monte Carlo algorithm to compare, in six-dimensional phase space, an 'observed' stream to models created in trial analytic potentials. We analyze a large sample of streams that evolved in the Via Lactea II (VL2) simulation, which represents a realistic Galactic halo potential. The recovered potential parameters are in agreement with the best fit to the global, present-day VL2 potential. However, merely assuming an analytic potential limits the dark matter halo mass measurement to an accuracy of 5%-20%, depending on the choice of analytic parameterization. Collectively, the mass estimates using streams from our sample reach this fundamental limit, but individually they can be highly biased. Individual streams can both under- and overestimate the mass, and the bias is progressively worse for those with smaller perigalacticons, motivating the search for tidal streams at galactocentric distances larger than 70 kpc. We estimate that the assumption of a static and smooth dark matter potential in modeling of the GD-1- and Pal5-like streams introduces an error of up to 50% in the Milky Way mass estimates.

  3. Using gaps in N-body tidal streams to probe missing satellites

    SciTech Connect

    Ngan, W. H. W.; Carlberg, R. G.

    2014-06-20

    We use N-body simulations to model the tidal disruption of a star cluster in a Milky-Way-sized dark matter halo, which results in a narrow stream comparable to (but slightly wider than) Pal-5 or GD-1. The mean Galactic dark matter halo is modeled by a spherical Navarro-Frenk-White potential with subhalos predicted by the ΛCDM cosmological model. The distribution and mass function of the subhalos follow the results from the Aquarius simulation. We use a matched filter approach to look for 'gaps' in tidal streams at 12 length scales from 0.1 kpc to 5 kpc, which appear as characteristic dips in the linear densities along the streams. We find that, in addition to the subhalos' perturbations, the epicyclic overdensities (EOs) due to the coherent epicyclic motions of particles in a stream also produce gap-like signals near the progenitor. We measure the gap spectra—the gap formation rates as functions of gap length—due to both subhalo perturbations and EOs, which have not been accounted for together by previous studies. Finally, we project the simulated streams onto the sky to investigate issues when interpreting gap spectra in observations. In particular, we find that gap spectra from low signal-to-noise observations can be biased by the orbital phase of the stream. This indicates that the study of stream gaps will benefit greatly from high-quality data from future missions.

  4. A scaling relation of the evolving tidal fields in a ?CDM cosmology

    SciTech Connect

    Lee, Jounghun [Astronomy Program, FPRD, Department of Physics and Astronomy, Seoul National University, Seoul 151-747 (Korea, Republic of); Springel, Volker, E-mail: jounghun@astro.snu.ac.kr, E-mail: volker@mpa-garching.mpg.de [Max-Planck Institut fuer Astrophysik, Karl-Schwarzschild Strasse 1, D-85748 Garching (Germany)

    2010-05-01

    We report the finding of a scaling relation among the cosmic-web anisotropy parameter A, the linear density rms fluctuation ?(r) and the linear growth factor D(z). Using the tidal field derived from the Millennium Simulation on 512{sup 3} grids at z = 0,2,5 and 127, we calculate the largest eigenvalues ? of the local tidal tensor at each grid resolution and measure its distance-averaged two-point correlation function, ?{sub ?}, as a function of the cosines of polar angles cos ? in the local principal axis frame. We show that ?{sub ?} is quite anisotropic, increasing toward the directions of minimal matter compression, and that the anisotropy of ?{sub ?} increases as the redshift z decreases and as the upper distance cutoff r{sub c} decreases. Fitting the numerical results to an analytic fitting model ?{sub ?}(cos ?)?(1+Acos {sup n}?){sup ?1}, it is found that the best fit value of A, dubbed the cosmic-web anisotropy parameter, varies systematically with ?(r{sub c}) and D(z), allowing us to determine the simple empiral scaling relation A(r{sub c},z) = 0.8 D{sup 0.76}(z) ?(r{sub c})

  5. Effect of non-uniform slow wave structure in a relativistic backward wave oscillator with a resonant reflector

    SciTech Connect

    Chen, Changhua; Xiao, Renzhen; Sun, Jun; Song, Zhimin; Huo, Shaofei; Bai, Xianchen; Shi, Yanchao; Liu, Guozhi

    2013-11-15

    This paper provides a fresh insight into the effect of non-uniform slow wave structure (SWS) used in a relativistic backward wave oscillator (RBWO) with a resonant reflector. Compared with the uniform SWS, the reflection coefficient of the non-uniform SWS is higher, leading to a lower modulating electric field in the resonant reflector and a larger distance to maximize the modulation current. Moreover, for both types of RBWOs, stronger standing-wave field takes place at the rear part of the SWS. In addition, besides Cerenkov effects, the energy conversion process in the RBWO strongly depends on transit time effects. Thus, the matching condition between the distributions of harmonic current and standing wave field provides a profound influence on the beam-wave interaction. In the non-uniform RBWO, the region with a stronger standing wave field corresponds to a higher fundamental harmonic current distribution. Particle-in-cell simulations show that with a diode voltage of 1.02 MV and beam current of 13.2 kA, a microwave power of 4 GW has been obtained, compared to that of 3 GW in the uniform RBWO.

  6. Current measuring system

    DOEpatents

    Dahl, David A.; Appelhans, Anthony D.; Olson, John E.

    1997-01-01

    A current measuring system comprising a current measuring device having a first electrode at ground potential, and a second electrode; a current source having an offset potential of at least three hundred volts, the current source having an output electrode; and a capacitor having a first electrode electrically connected to the output electrode of the current source and having a second electrode electrically connected to the second electrode of the current measuring device.

  7. Current measuring system

    DOEpatents

    Dahl, D.A.; Appelhans, A.D.; Olson, J.E.

    1997-09-09

    A current measuring system is disclosed comprising a current measuring device having a first electrode at ground potential, and a second electrode; a current source having an offset potential of at least three hundred volts, the current source having an output electrode; and a capacitor having a first electrode electrically connected to the output electrode of the current source and having a second electrode electrically connected to the second electrode of the current measuring device. 4 figs.

  8. Current Power Rates

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    links Financial Information Financial Public Processes Asset Management Cost Verification Process Rate Cases Rate Information Current Power Rates Current Transmission Rates...

  9. Current Transmission Rates

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    links Financial Information Financial Public Processes Asset Management Cost Verification Process Rate Cases Rate Information Current Power Rates Current Transmission Rates...

  10. Current measurement apparatus

    DOEpatents

    Umans, Stephen D.

    2008-11-11

    Apparatus and methods are provided for a system for measurement of a current in a conductor such that the conductor current may be momentarily directed to a current measurement element in order to maintain proper current without significantly increasing an amount of power dissipation attributable to the current measurement element or adding resistance to assist in current measurement. The apparatus and methods described herein are useful in superconducting circuits where it is necessary to monitor current carried by the superconducting elements while minimizing the effects of power dissipation attributable to the current measurement element.

  11. Ecology of Juvenile Salmon in Shallow Tidal Freshwater Habitats of the Lower Columbia River, 2007–2010

    SciTech Connect

    Johnson, Gary E.; Storch, Adam; Skalski, J. R.; Bryson, Amanda J.; Mallette, Christine; Borde, Amy B.; Van Dyke, E.; Sobocinski, Kathryn L.; Sather, Nichole K.; Teel, David; Dawley, Earl M.; Ploskey, Gene R.; Jones, Tucker A.; Zimmerman, Shon A.; Kuligowski, D. R.

    2011-03-01

    The TFM study was designed to investigate the ecology and early life history of juvenile salmonids within shallow (<5 m) tidal freshwater habitats of the LCRE. We started collecting field data in June 2007. Since then, monthly sampling has occurred in the vicinity of the Sandy River delta (rkm 192–208) and at other sites and times in lower river reaches of tidal freshwater (rkm 110 to 141). This report provides a comprehensive synthesis of data covering the field period from June 2007 through April 2010.

  12. Scaling of lower hybrid current drive with temperature

    SciTech Connect

    Harvey, R.W. ); McCoy, M.G. ); Ram, A.K.; Bers, A. ); Fuchs, V. )

    1992-06-01

    The 3-D Fokker-Planck/quasilinear code (CQL3D) is used to study the temperature scaling of lower hybrid current drive (LHCD) in the JET and JT-60 experiments. An offset-linear increase of current drive efficiency is obtained as a function of volume average temperature {l angle}T{sub e}{r angle} up to {approximately} 2.5, and reduced rate of efficiency increase is found at higher temperatures. The LHCD results indicate some fast wave/LH current drive synergy in the JET LH/FW experiments; however, code results discussed here show that synergy is not due to TTMP damping of the fast wave.

  13. Benchmark Modeling of the Near-Field and Far-Field Wave Effects of Wave Energy Arrays

    SciTech Connect

    Rhinefrank, Kenneth E; Haller, Merrick C; Ozkan-Haller, H Tuba

    2013-01-26

    This project is an industry-led partnership between Columbia Power Technologies and Oregon State University that will perform benchmark laboratory experiments and numerical modeling of the near-field and far-field impacts of wave scattering from an array of wave energy devices. These benchmark experimental observations will help to fill a gaping hole in our present knowledge of the near-field effects of multiple, floating wave energy converters and are a critical requirement for estimating the potential far-field environmental effects of wave energy arrays. The experiments will be performed at the Hinsdale Wave Research Laboratory (Oregon State University) and will utilize an array of newly developed Buoys' that are realistic, lab-scale floating power converters. The array of Buoys will be subjected to realistic, directional wave forcing (1:33 scale) that will approximate the expected conditions (waves and water depths) to be found off the Central Oregon Coast. Experimental observations will include comprehensive in-situ wave and current measurements as well as a suite of novel optical measurements. These new optical capabilities will include imaging of the 3D wave scattering using a binocular stereo camera system, as well as 3D device motion tracking using a newly acquired LED system. These observing systems will capture the 3D motion history of individual Buoys as well as resolve the 3D scattered wave field; thus resolving the constructive and destructive wave interference patterns produced by the array at high resolution. These data combined with the device motion tracking will provide necessary information for array design in order to balance array performance with the mitigation of far-field impacts. As a benchmark data set, these data will be an important resource for testing of models for wave/buoy interactions, buoy performance, and far-field effects on wave and current patterns due to the presence of arrays. Under the proposed project we will initiate high

  14. Haynes Wave Basin | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Wave Basin Jump to: navigation, search Basic Specifications Facility Name Haynes Wave Basin Overseeing Organization Texas A&M (Haynes) Hydrodynamic Testing Facility Type Wave Basin...

  15. Wave Star Energy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Star Energy Jump to: navigation, search Name: Wave Star Energy Place: Denmark Zip: DK-2920 Product: Denmark-based private wave device developer. References: Wave Star Energy1...

  16. Microfabricated bulk wave acoustic bandgap device (Patent) |...

    Office of Scientific and Technical Information (OSTI)

    Microfabricated bulk wave acoustic bandgap device Title: Microfabricated bulk wave acoustic bandgap device A microfabricated bulk wave acoustic bandgap device comprises a periodic ...

  17. Elgen Wave | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Elgen Wave Jump to: navigation, search Name: Elgen Wave Region: United States Sector: Marine and Hydrokinetic Website: www.elgenwave.com This company is listed in the Marine and...

  18. Kinetic Theory of Plasma Waves - Part I: Introduction

    SciTech Connect

    Lamalle, P.U

    2004-03-15

    The kinetic description of linear waves in plasmas is succinctly presented, with emphasis on applications to high-frequency (hf) wave heating and current drive. The Maxwell-Vlasov system of equations is introduced. Its two-timescale analysis yields the linearized Vlasov and the quasilinear Fokker-Planck equations. The standard guiding centre and Hamiltonian formalisms are presented. Two formulations of the hf plasma wave equation are given: as a partial differential equation to hold at each position, and as a global Galerkin ('variational') form.

  19. EXPERIMENTAL STUDY OF SHOCK WAVE DYNAMICS IN MAGNETIZED PLASMAS

    SciTech Connect

    Nirmol K. Podder

    2009-03-17

    In this four-year project (including one-year extension), the project director and his research team built a shock-wave-plasma apparatus to study shock wave dynamics in glow discharge plasmas in nitrogen and argon at medium pressure (1–20 Torr), carried out various plasma and shock diagnostics and measurements that lead to increased understanding of the shock wave acceleration phenomena in plasmas. The measurements clearly show that in the steady-state dc glow discharge plasma, at fixed gas pressure the shock wave velocity increases, its amplitude decreases, and the shock wave disperses non-linearly as a function of the plasma current. In the pulsed discharge plasma, at fixed gas pressure the shock wave dispersion width and velocity increase as a function of the delay between the switch-on of the plasma and shock-launch. In the afterglow plasma, at fixed gas pressure the shock wave dispersion width and velocity decrease as a function of the delay between the plasma switch-off and shock-launch. These changes are found to be opposite and reversing towards the room temperature value which is the initial condition for plasma ignition case. The observed shock wave properties in both igniting and afterglow plasmas correlate well with the inferred temperature changes in the two plasmas.

  20. Method and apparatus for generating motor current spectra to enhance motor system fault detection

    DOEpatents

    Linehan, D.J.; Bunch, S.L.; Lyster, C.T.

    1995-10-24

    A method and circuitry are disclosed for sampling periodic amplitude modulations in a nonstationary periodic carrier wave to determine frequencies in the amplitude modulations. The method and circuit are described in terms of an improved motor current signature analysis. The method insures that the sampled data set contains an exact whole number of carrier wave cycles by defining the rate at which samples of motor current data are collected. The circuitry insures that a sampled data set containing stationary carrier waves is recreated from the analog motor current signal containing nonstationary carrier waves by conditioning the actual sampling rate to adjust with the frequency variations in the carrier wave. After the sampled data is transformed to the frequency domain via the Discrete Fourier Transform, the frequency distribution in the discrete spectra of those components due to the carrier wave and its harmonics will be minimized so that signals of interest are more easily analyzed. 29 figs.

  1. Method and apparatus for generating motor current spectra to enhance motor system fault detection

    DOEpatents

    Linehan, Daniel J.; Bunch, Stanley L.; Lyster, Carl T.

    1995-01-01

    A method and circuitry for sampling periodic amplitude modulations in a nonstationary periodic carrier wave to determine frequencies in the amplitude modulations. The method and circuit are described in terms of an improved motor current signature analysis. The method insures that the sampled data set contains an exact whole number of carrier wave cycles by defining the rate at which samples of motor current data are collected. The circuitry insures that a sampled data set containing stationary carrier waves is recreated from the analog motor current signal containing nonstationary carrier waves by conditioning the actual sampling rate to adjust with the frequency variations in the carrier wave. After the sampled data is transformed to the frequency domain via the Discrete Fourier Transform, the frequency distribution in the discrete spectra of those components due to the carrier wave and its harmonics will be minimized so that signals of interest are more easily analyzed.

  2. None Currently | Princeton Plasma Physics Lab

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    None Currently

  3. Current practices and new technology in ocean engineering

    SciTech Connect

    McGuinness, T.; Shih, H.H.

    1986-01-01

    This book presents the papers given at a conference on wave power and marine engineering. Topics considered at the conference included remote sensing, ocean current measurement, air and spaceborne instrumentation, marine dynamics, real-time measurements, telemetry systems, seafloor measurement, computer-based data acquisition, materials and devices for underwater work systems, ocean system design analysis and reliability, ocean structure fatigue life prediction, underwater life support systems, sensor design, ocean thermal energy conversion, and wave energy converters.

  4. STAR FORMATION AND DUST OBSCURATION IN THE TIDALLY DISTORTED GALAXY NGC 2442

    SciTech Connect

    Pancoast, Anna; Sajina, Anna; Lacy, Mark; Noriega-Crespo, Alberto; Rho, Jeonghee

    2010-11-01

    We present a detailed investigation of the morphological distribution and level of star formation and dust obscuration in the nearby tidally distorted galaxy NGC 2442. Spitzer images in the IR at 3.6, 4.5, 5.8, 8.0, and 24 {mu}m and GALEX images at 1500 A and 2300 A allow us to resolve the galaxy on scales between {approx}240 and 600 pc. We supplement these with archival data in the B, J, H, and K bands. We use the 8 {mu}m, 24 {mu}m, and FUV (1500 A) emission to study the star formation rate (SFR). We find that, globally, these tracers of star formation give a range of results of {approx}6-11 M{sub sun} yr{sup -1}, with the dust-corrected FUV giving the highest value of SFR. We can reconcile the UV- and IR-based estimates by adopting a steeper UV extinction curve that lies in between the starburst (Calzetti) and Small Magellanic Cloud extinction curves. However, the regions of the highest SFR intensity along the spiral arms are consistent with a starburst-like extinction. Overall, the level of star formation we find is higher than previously published for this galaxy, by about a factor of 2, which, contrary to previous conclusions, implies that the interaction that caused the distorted morphology of NGC 2442 likely also triggered increased levels of star formation activity. We also find marked asymmetry in that the north spiral arm has a noticeably higher SFR than the southern arm. The tip of the southern spiral arm shows a likely tidally distorted peculiar morphology. It is UV bright and shows unusual IRAC colors, consistent with other published tidal features IRAC data. Outside of the spiral arms, we discover what appears to be a superbubble, {approx}1.7 kpc across, which is seen most clearly in the IRAC images. Significant H{alpha}, UV, and IR emission in the area also suggest vigorous ongoing star formation. A known, recent supernova (SN 1999ga) is located at the edge of this superbubble. Although speculative at this stage, this area suggests a large star

  5. Property:Maximum Wave Height(m) at Wave Period(s) | Open Energy...

    OpenEI (Open Energy Information) [EERE & EIA]

    at Wave Period(s) Jump to: navigation, search Property Name Maximum Wave Height(m) at Wave Period(s) Property Type String Pages using the property "Maximum Wave Height(m) at Wave...

  6. Charge Density Wave Compounds

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Fisher Research Group Layered Chalcogenides 29 February 2008 Controlling the Wave by Brad Plummer, SLAC Communications Stanford University researchers working in part at SSRL have discovered a novel set of properties pertaining to a compound of materials called tritellurides. These compounds, composed of three atoms of tellurium and a single atom of one of the rare earth elements, demonstrate unique electronic properties that can be controlled by altering the temperature of the material. The

  7. A statistical study of EMIC waves observed by Cluster. 1. Wave properties. EMIC Wave Properties

    SciTech Connect

    Allen, R. C.; Zhang, J. -C.; Kistler, L. M.; Spence, H. E.; Lin, R. -L.; Klecker, B.; Dunlop, M. W.; Andr, M.; Jordanova, V. K.

    2015-07-23

    Electromagnetic ion cyclotron (EMIC) waves are an important mechanism for particle energization and losses inside the magnetosphere. In order to better understand the effects of these waves on particle dynamics, detailed information about the occurrence rate, wave power, ellipticity, normal angle, energy propagation angle distributions, and local plasma parameters are required. Previous statistical studies have used in situ observations to investigate the distribution of these parameters in the magnetic local time versus L-shell (MLT-L) frame within a limited magnetic latitude (MLAT) range. In our study, we present a statistical analysis of EMIC wave properties using 10 years (20012010) of data from Cluster, totaling 25,431 min of wave activity. Due to the polar orbit of Cluster, we are able to investigate EMIC waves at all MLATs and MLTs. This allows us to further investigate the MLAT dependence of various wave properties inside different MLT sectors and further explore the effects of Shabansky orbits on EMIC wave generation and propagation. Thus, the statistical analysis is presented in two papers. OUr paper focuses on the wave occurrence distribution as well as the distribution of wave properties. The companion paper focuses on local plasma parameters during wave observations as well as wave generation proxies.

  8. A statistical study of EMIC waves observed by Cluster. 1. Wave properties. EMIC Wave Properties

    DOE PAGES [OSTI]

    Allen, R. C.; Zhang, J. -C.; Kistler, L. M.; Spence, H. E.; Lin, R. -L.; Klecker, B.; Dunlop, M. W.; André, M.; Jordanova, V. K.

    2015-07-23

    Electromagnetic ion cyclotron (EMIC) waves are an important mechanism for particle energization and losses inside the magnetosphere. In order to better understand the effects of these waves on particle dynamics, detailed information about the occurrence rate, wave power, ellipticity, normal angle, energy propagation angle distributions, and local plasma parameters are required. Previous statistical studies have used in situ observations to investigate the distribution of these parameters in the magnetic local time versus L-shell (MLT-L) frame within a limited magnetic latitude (MLAT) range. In our study, we present a statistical analysis of EMIC wave properties using 10 years (2001–2010) of datamore » from Cluster, totaling 25,431 min of wave activity. Due to the polar orbit of Cluster, we are able to investigate EMIC waves at all MLATs and MLTs. This allows us to further investigate the MLAT dependence of various wave properties inside different MLT sectors and further explore the effects of Shabansky orbits on EMIC wave generation and propagation. Thus, the statistical analysis is presented in two papers. OUr paper focuses on the wave occurrence distribution as well as the distribution of wave properties. The companion paper focuses on local plasma parameters during wave observations as well as wave generation proxies.« less

  9. A statistical study of EMIC waves observed by Cluster. 1. Wave properties. EMIC Wave Properties

    SciTech Connect

    Allen, R. C.; Zhang, J. -C.; Kistler, L. M.; Spence, H. E.; Lin, R. -L.; Klecker, B.; Dunlop, M. W.; André, M.; Jordanova, V. K.

    2015-07-23

    Electromagnetic ion cyclotron (EMIC) waves are an important mechanism for particle energization and losses inside the magnetosphere. In order to better understand the effects of these waves on particle dynamics, detailed information about the occurrence rate, wave power, ellipticity, normal angle, energy propagation angle distributions, and local plasma parameters are required. Previous statistical studies have used in situ observations to investigate the distribution of these parameters in the magnetic local time versus L-shell (MLT-L) frame within a limited magnetic latitude (MLAT) range. In our study, we present a statistical analysis of EMIC wave properties using 10 years (2001–2010) of data from Cluster, totaling 25,431 min of wave activity. Due to the polar orbit of Cluster, we are able to investigate EMIC waves at all MLATs and MLTs. This allows us to further investigate the MLAT dependence of various wave properties inside different MLT sectors and further explore the effects of Shabansky orbits on EMIC wave generation and propagation. Thus, the statistical analysis is presented in two papers. OUr paper focuses on the wave occurrence distribution as well as the distribution of wave properties. The companion paper focuses on local plasma parameters during wave observations as well as wave generation proxies.

  10. Anomalous - viscosity current drive

    DOEpatents

    Stix, Thomas H.; Ono, Masayuki

    1988-01-01

    An apparatus and method for maintaining a steady-state current in a toroidal magnetically confined plasma. An electric current is generated in an edge region at or near the outermost good magnetic surface of the toroidal plasma. The edge current is generated in a direction parallel to the flow of current in the main plasma and such that its current density is greater than the average density of the main plasma current. The current flow in the edge region is maintained in a direction parallel to the main current for a period of one or two of its characteristic decay times. Current from the edge region will penetrate radially into the plasma and augment the main plasma current through the mechanism of anomalous viscosity. In another aspect of the invention, current flow driven between a cathode and an anode is used to establish a start-up plasma current. The plasma-current channel is magnetically detached from the electrodes, leaving a plasma magnetically insulated from contact with any material obstructions including the cathode and anode.

  11. A LUMINOUS, FAST RISING UV-TRANSIENT DISCOVERED BY ROTSE: A TIDAL DISRUPTION EVENT?

    SciTech Connect

    Vink, J.; Wheeler, J. C.; Chatzopoulos, E.; Marion, G. H.; Yuan, F.; Akerlof, C.; Quimby, R. M.; Ramirez-Ruiz, E.; Guillochon, J.

    2015-01-01

    We present follow-up observations of an optical transient (OT) discovered by ROTSE on 2009 January 21. Photometric monitoring was carried out with ROTSE-IIIb in the optical and Swift in the UV up to +70 days after discovery. The light curve showed a fast rise time of ?10 days followed by a steep decline over the next 60 days, which was much faster than that implied by {sup 56}Ni{sup 56}Co radioactive decay. The Sloan Digital Sky Survey Data Release 10 database contains a faint, red object at the position of the OT, which appears slightly extended. This and other lines of evidence suggest that the OT is of extragalactic origin, and this faint object is likely the host galaxy. A sequence of optical spectra obtained with the 9.2m Hobby-Eberly Telescope between +8 and +45 days after discovery revealed a hot, blue continuum with no visible spectral features. A few weak features that appeared after +30 days probably originated from the underlying host. Fitting synthetic templates to the observed spectrum of the host galaxy revealed a redshift of z = 0.19. At this redshift, the peak magnitude of the OT is close to 22.5, similar to the brightest super-luminous supernovae; however, the lack of identifiable spectral features makes the massive stellar death hypothesis less likely. A more plausible explanation appears to be the tidal disruption of a Sun-like star by the central supermassive black hole. We argue that this transient likely belongs to a class of super-Eddington tidal disruption events.

  12. EXTREME CORONAL LINE EMITTERS: TIDAL DISRUPTION OF STARS BY MASSIVE BLACK HOLES IN GALACTIC NUCLEI?

    SciTech Connect

    Wang Tinggui; Zhou Hongyan; Wang Huiyuan; Yang Chenwei; Komossa, S.

    2012-04-20

    Tidal disruption of stars by supermassive black holes at the centers of galaxies is expected to produce unique emission-line signatures, which have not yet been explored adequately. Here we report the discovery of extremely strong coronal lines from [Fe X] up to [Fe XIV] in a sample of seven galaxies (including two recently reported cases), which we interpret as such signatures. This is the first systematic search for objects of this kind, by making use of the immense database of the Sloan Digital Sky Survey. The galaxies, which are non-active as evidenced by the narrow line ratios, show broad emission lines of complex profiles in more than half of the sample. Both the high-ionization coronal lines and the broad lines are fading on timescales of years in objects observed with spectroscopic follow-ups, suggesting their transient nature. Variations of inferred non-stellar continua, which have absolute magnitudes of at least -16 to -18 mag in the g band, are also detected in more than half of the sample. The coronal line emitters reside in sub-L{sub *} disk galaxies (-21.3 < M{sub i} < -18.5) with small stellar velocity dispersions. The sample seems to form two distinct types based on the presence or absence of the [Fe VII] lines, with the latter having relatively low luminosities of [O III], [Fe XI], and the host galaxies. These characteristics can most naturally be understood in the context of transient accretion onto intermediate-mass black holes at galactic centers following tidal disruption of stars in a gas-rich environment. We estimate the incidence of such events to be around 10{sup -5} yr{sup -1} for a galaxy with -21.3 < M{sub i} < -18.5.

  13. Reservoir facies architecture in a micro-tidal barrier system, Frio formation, Texas Gulf Coast

    SciTech Connect

    Galloway, W.E.

    1984-04-01

    Barrier-bar sand bodies are a complex mosaic of barrier-core, shore-face, inlet-fill, tidal-delta, and back-barrier facies. In addition, sandbody stratigraphy and internal depositional architecture are determined by the progradational, aggradational, or transgressive origin of the barrier complex. The Frio barrier/strandplain system of the middle Texas Gulf Coast has produced more than 3 billion bbl of oil. Examination of the Greta, Glasscock, and 41-A sands in West Ranch field illustrates the variability of barrier reservoirs. Each reservoir is a mosaic of variably interconnected compartments having sheet, tab, pod, or channel geometries. Conventional facies analysis (isolith and log-pattern mapping and limited core examination) combined with semiquantitative delineation of hydrocarbon-saturation distribution using resistivity logs defined the facies components of each reservoir. The 41-A sand consists of juxtaposed progradational barrier-core, inlet-fill, and flood tidal-delta units. The Glasscock sand is largely a transgressive barrier-flat and washover-fan deposit. The Greta sand is a complex of aggradational barrier-core and inlet-fill facies. Productive attributes of each reservoir are influenced by its facies architecture and attendant relative permeabilities. Natural water drive is ineffective in the volumetrically restricted transgressive Glasscock reservoir. Permeability distribution in the 41-A reservoir is facies defined. Erratic injection response, irregular oil-water contact advance, and variable water/oil ratios observed during the productive history of individual reservoirs document localized facies effects on fluid flow. Spatial variation of the gas/oil ratio may also reflect facies distribution.

  14. Wave-function functionals

    SciTech Connect

    Pan Xiaoyin; Slamet, Marlina; Sahni, Viraht

    2010-04-15

    We extend our prior work on the construction of variational wave functions {psi} that are functionals of functions {chi}:{psi}={psi}[{chi}] rather than simply being functions. In this manner, the space of variations is expanded over those of traditional variational wave functions. In this article we perform the constrained search over the functions {chi} chosen such that the functional {psi}[{chi}] satisfies simultaneously the constraints of normalization and the exact expectation value of an arbitrary single- or two-particle Hermitian operator, while also leading to a rigorous upper bound to the energy. As such the wave function functional is accurate not only in the region of space in which the principal contributions to the energy arise but also in the other region of the space represented by the Hermitian operator. To demonstrate the efficacy of these ideas, we apply such a constrained search to the ground state of the negative ion of atomic hydrogen H{sup -}, the helium atom He, and its positive ions Li{sup +} and Be{sup 2+}. The operators W whose expectations are obtained exactly are the sum of the single-particle operators W={Sigma}{sub i}r{sub i}{sup n},n=-2,-1,1,2, W={Sigma}{sub i{delta}}(r{sub i}), W=-(1/2){Sigma}{sub i{nabla}i}{sup 2}, and the two-particle operators W={Sigma}{sub n}u{sup n},n=-2,-1,1,2, where u=|r{sub i}-r{sub j}|. Comparisons with the method of Lagrangian multipliers and of other constructions of wave-function functionals are made. Finally, we present further insights into the construction of wave-function functionals by studying a previously proposed construction of functionals {psi}[{chi}] that lead to the exact expectation of arbitrary Hermitian operators. We discover that analogous to the solutions of the Schroedinger equation, there exist {psi}[{chi}] that are unphysical in that they lead to singular values for the expectations. We also explain the origin of the singularity.

  15. About Direct Current

    Energy.gov [DOE]

    Learn about Direct Current -- a podcast about the energy that lights our homes, powers our lives and shapes our world.

  16. CIRCUITS FOR CURRENT MEASUREMENTS

    DOEpatents

    Cox, R.J.

    1958-11-01

    Circuits are presented for measurement of a logarithmic scale of current flowing in a high impedance. In one form of the invention the disclosed circuit is in combination with an ionization chamber to measure lonization current. The particular circuit arrangement lncludes a vacuum tube having at least one grid, an ionization chamber connected in series with a high voltage source and the grid of the vacuum tube, and a d-c amplifier feedback circuit. As the ionization chamber current passes between the grid and cathode of the tube, the feedback circuit acts to stabilize the anode current, and the feedback voltage is a measure of the logaritbm of the ionization current.

  17. WAVE DELAYING STRUCTURE FOR RECTANGULAR WAVE-GUIDES

    DOEpatents

    Robertson-Shersby-Harvie, R.B.; Dain, J.

    1956-11-13

    This patent relates to wave-guides and in particular describes wave delaying structure located within a wave-guide. The disclosed wave-guide has an elongated fiat metal sheet arranged in a central plane of the guide and formed with a series of transverse inductive slots such that each face presents an inductive impedance to the guide. The sheet is thickened in the area between slots to increase the self capacity of the slots. Experimental results indicate that in a wave-guide loaded in accordance with the invention the guided wavelength changes more slowly as the air wavelength is changed than the guided wavelength does in wave-guides loaded by means of corrugations.

  18. Wave Energy Converter Effects on Nearshore Wave Propagation

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Energy Converter Effects on Nearshore Wave Propagation Jesse Roberts 1 , Grace Chang *2 , Craig Jones *3 Sandia National Laboratories 1515 Eubank SE, Albuquerque, NM 87123 USA 1...

  19. Conversion of borehole Stoneley waves to channel waves in coal

    SciTech Connect

    Johnson, P.A.; Albright, J.N.

    1987-01-01

    Evidence for the mode conversion of borehole Stoneley waves to stratigraphically guided channel waves was discovered in data from a crosswell acoustic experiment conducted between wells penetrating thin coal strata located near Rifle, Colorado. Traveltime moveout observations show that borehole Stoneley waves, excited by a transmitter positioned at substantial distances in one well above and below a coal stratum at 2025 m depth, underwent partial conversion to a channel wave propagating away from the well through the coal. In an adjacent well the channel wave was detected at receiver locations within the coal, and borehole Stoneley waves, arising from a second partial conversion of channel waves, were detected at locations above and below the coal. The observed channel wave is inferred to be the third-higher Rayleigh mode based on comparison of the measured group velocity with theoretically derived dispersion curves. The identification of the mode conversion between borehole and stratigraphically guided waves is significant because coal penetrated by multiple wells may be detected without placing an acoustic transmitter or receiver within the waveguide. 13 refs., 6 figs., 1 tab.

  20. Spin waves in the (

    SciTech Connect

    Lipscombe, O. J.; Chen, G. F.; Fang, Chen; Perring, T. G.; Abernathy, Douglas L; Christianson, Andrew D; Egami, Takeshi; Wang, Nanlin; Hu, Jiangping; Dai, Pengcheng

    2011-01-01

    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.

  1. The Contribution of Environmental Siting and Permitting Requirements to the Cost of Energy for Wave Energy Devices

    SciTech Connect

    Copping, Andrea E.; Geerlofs, Simon H.; Hanna, Luke A.

    2014-06-30

    Responsible deployment of marine and hydrokinetic (MHK) devices in estuaries, coastal areas, and major rivers requires that biological resources and ecosystems be protected through siting and permitting (consenting) processes. Scoping appropriate deployment locations, collecting pre-installation (baseline) and post-installation data all add to the cost of developing MHK projects, and hence to the cost of energy. Under the direction of the U.S. Department of Energy, Pacific Northwest National Laboratory scientists have developed logic models that describe studies and processes for environmental siting and permitting. Each study and environmental permitting process has been assigned a cost derived from existing and proposed tidal, wave, and riverine MHK projects. Costs have been developed at the pilot scale and for commercial arrays for a surge wave energy converter

  2. Effects of Tidal Turbine Noise on Fish Hearing and Tissues - Draft Final Report - Environmental Effects of Marine and Hydrokinetic Energy

    SciTech Connect

    Halvorsen, Michele B.; Carlson, Thomas J.; Copping, Andrea E.

    2011-09-30

    Snohomish Public Utility District No.1 plans to deploy two 6 meter OpenHydro tidal turbines in Admiralty Inlet in Puget Sound, under a FERC pilot permitting process. Regulators and stakeholders have raised questions about the potential effect of noise from the turbines on marine life. Noise in the aquatic environment is known to be a stressor to many types of aquatic life, including marine mammals, fish and birds. Marine mammals and birds are exceptionally difficult to work with for technical and regulatory reasons. Fish have been used as surrogates for other aquatic organisms as they have similar auditory structures. This project was funded under the FY09 Funding Opportunity Announcement (FOA) to Snohomish PUD, in partnership with the University of Washington - Northwest National Marine Renewable Energy Center, the Sea Mammal Research Unit, and Pacific Northwest National Laboratory. The results of this study will inform the larger research project outcomes. Proposed tidal turbine deployments in coastal waters are likely to propagate noise into nearby waters, potentially causing stress to native organisms. For this set of experiments, juvenile Chinook salmon (Oncorhynchus tshawytscha) were used as the experimental model. Plans exist for prototype tidal turbines to be deployed into their habitat. Noise is known to affect fish in many ways, such as causing a threshold shift in auditory sensitivity or tissue damage. The characteristics of noise, its spectra and level, are important factors that influence the potential for the noise to injure fish. For example, the frequency range of the tidal turbine noise includes the audiogram (frequency range of hearing) of most fish. This study was performed during FY 2011 to determine if noise generated by a 6-m diameter OpenHydro turbine might affect juvenile Chinook salmon hearing or cause barotrauma. Naturally spawning stocks of Chinook salmon that utilize Puget Sound are listed as threatened (http://www.nwr.noaa

  3. Gravitational Waves from Coalescing Binary Black Holes: Theoretical and Experimental Challenges

    ScienceCinema

    None

    2016-07-12

    A network of ground-based interferometric gravitational wave detectors (LIGO/VIRGO/GEO/...) is currently taking data near its planned sensitivity. Coalescing black hole binaries are among the most promising, and most exciting, gravitational wave sources for these detectors. The talk will review the theoretical and experimental challenges that must be met in order to successfully detect gravitational waves from coalescing black hole binaries, and to be able to reliably measure the physical parameters of the source (masses, spins, ...).

  4. Electric current locator

    DOEpatents

    King, Paul E.; Woodside, Charles Rigel

    2012-02-07

    The disclosure herein provides an apparatus for location of a quantity of current vectors in an electrical device, where the current vector has a known direction and a known relative magnitude to an input current supplied to the electrical device. Mathematical constants used in Biot-Savart superposition equations are determined for the electrical device, the orientation of the apparatus, and relative magnitude of the current vector and the input current, and the apparatus utilizes magnetic field sensors oriented to a sensing plane to provide current vector location based on the solution of the Biot-Savart superposition equations. Description of required orientations between the apparatus and the electrical device are disclosed and various methods of determining the mathematical constants are presented.

  5. When shock waves collide

    DOE PAGES [OSTI]

    Martinez, D.; Hartigan, P.; Frank, A.; Hansen, E.; Yirak, K.; Liao, A. S.; Graham, P.; Foster, J.; Wilde, B.; Blue, B.; et al

    2016-06-01

    Supersonic outflows from objects as varied as stellar jets, massive stars, and novae often exhibit multiple shock waves that overlap one another. When the intersection angle between two shock waves exceeds a critical value, the system reconfigures its geometry to create a normal shock known as a Mach stem where the shocks meet. Mach stems are important for interpreting emission-line images of shocked gas because a normal shock produces higher postshock temperatures, and therefore a higher-excitation spectrum than does an oblique shock. In this paper, we summarize the results of a series of numerical simulations and laboratory experiments designed tomore » quantify how Mach stems behave in supersonic plasmas that are the norm in astrophysical flows. The experiments test analytical predictions for critical angles where Mach stems should form, and quantify how Mach stems grow and decay as intersection angles between the incident shock and a surface change. While small Mach stems are destroyed by surface irregularities and subcritical angles, larger ones persist in these situations and can regrow if the intersection angle changes to become more favorable. Furthermore, the experimental and numerical results show that although Mach stems occur only over a limited range of intersection angles and size scales, within these ranges they are relatively robust, and hence are a viable explanation for variable bright knots observed in Hubble Space Telescope images at the intersections of some bow shocks in stellar jets.« less

  6. Current Solicitations - Hanford Site

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    DOE-RL Contracts/Procurements Current Solicitations DOE-RL Contracts/Procurements RL Contracts & Procurements Home Prime Contracts Current Solicitations Other Sources DOE RL Contracting Officers DOE RL Contracting Officer Representatives Current Solicitations Email Email Page | Print Print Page | Text Increase Font Size Decrease Font Size The Richland Operations Office uses Fedconnect (https://www.fedconnect.net) to post solicitations on FedBizOps. Quotes/proposals are also received using

  7. Generation of broadband terahertz radiation using a backward wave oscillator and pseudospark-sourced electron beam

    SciTech Connect

    He, W.; Zhang, L.; Bowes, D.; Yin, H.; Ronald, K.; Phelps, A. D. R.; Cross, A. W.

    2015-09-28

    This paper presents for the generation of a small size high current density pseudospark (PS) electron beam for a high frequency (0.2 THz) Backward Wave Oscillator (BWO) through a Doppler up-shift of the plasma frequency. An electron beam ∼1 mm diameter carrying a current of up to 10 A and current density of 10{sup 8} A m{sup −2}, with a sweeping voltage of 42 to 25 kV and pulse duration of 25 ns, was generated from the PS discharge. This beam propagated through the rippled-wall slow wave structure of a BWO beam-wave interaction region in a plasma environment without the need for a guiding magnetic field. Plasma wave assisted beam-wave interaction resulted in broadband output over a frequency range of 186–202 GHz with a maximum power of 20 W.

  8. Current Annualized Request

    Office of Environmental Management (EM)

    Appropriation FY 2012 FY 2013 FY 2014 Current Annualized Request CR % Energy And Water Development, And Related Agencies Energy Programs Energy Efficiency and Renewable Energy...

  9. Fault Current Limiters

    Energy Saver

    Fault Current Limiters Superconducting & Solid-state Power Equipment Office of Electricity Delivery and Energy Reliability www.oe.energy.gov Office of Electricity Delivery and ...

  10. RF current sensor

    DOEpatents

    Moore, James A.; Sparks, Dennis O.

    1998-11-10

    An RF sensor having a novel current sensing probe and a voltage sensing probe to measure voltage and current. The current sensor is disposed in a transmission line to link all of the flux generated by the flowing current in order to obtain an accurate measurement. The voltage sensor is a flat plate which operates as a capacitive plate to sense voltage on a center conductor of the transmission line, in which the measured voltage is obtained across a resistance leg of a R-C differentiator circuit formed by the characteristic impedance of a connecting transmission line and a capacitance of the plate, which is positioned proximal to the center conductor.

  11. Current Testbed Research

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Current Testbed Research Previous Testbed Research Proposal Process Terms and Conditions Dark Fiber Testbed Federated Testbed Circuits Test Circuit Service Performance (perfSONAR)...

  12. Wave energy and intertidal productivity

    SciTech Connect

    Leigh, E.G. Jr.; Paine, R.T.; Quinn, J.F.; Suchanek, T.H.

    1987-03-01

    In the northern Pacific, intertidal zones of the most wave-beaten shores receive more energy from breaking waves than from the sun. Despite severe mortality from winter storms, communities at some wave-beaten sites produce an extraordinary quantity of dry matter per unit area of shore per year. At wave-beaten sites of Tatoosh Island, WA, sea palms, Postelsia palmaeformis, can produce > 10 kg of dry matter, or 1.5 x 10/sup 8/ J, per m/sup 2/ in a good year. Extraordinarily productive organisms such as Postelsia are restricted to wave-beaten sites. Intertidal organisms cannot transform wave energy into chemical energy, as photosynthetic plants transform solar energy, nor can intertidal organisms harness wave energy. Nonetheless, wave energy enhances the productivity of intertidal organisms. On exposed shores, waves increase the capacity of resident algae to acquire nutrients and use sunlight, augment the competitive ability of productive organism, and protect intertidal residents by knocking away their enemies or preventing them from feeding.

  13. advanced wave energy control design

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    wave energy control design - Sandia Energy Energy Search Icon Sandia Home Locations Contact Us Employee Locator Energy & Climate Secure & Sustainable Energy Future Stationary Power ...

  14. Guided acoustic wave inspection system

    DOEpatents

    Chinn, Diane J.

    2004-10-05

    A system for inspecting a conduit for undesirable characteristics. A transducer system induces guided acoustic waves onto said conduit. The transducer system detects the undesirable characteristics of the conduit by receiving guided acoustic waves that contain information about the undesirable characteristics. The conduit has at least two sides and the transducer system utilizes flexural modes of propagation to provide inspection using access from only the one side of the conduit. Cracking is detected with pulse-echo testing using one transducer to both send and receive the guided acoustic waves. Thinning is detected in through-transmission testing where one transducer sends and another transducer receives the guided acoustic waves.

  15. Harnessing Energy from Ocean Waves

    SciTech Connect

    Lehmann, Marcus

    2015-05-06

    Berkeley Lab scientist Marcus Lehmann, a member of the Lab's Cyclotron Road cohort, discusses his research on harnessing energy from ocean waves.

  16. Wave Basin | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Basin Jump to: navigation, search Retrieved from "http:en.openei.orgwindex.php?titleWaveBasin&oldid596392" Feedback Contact needs updating Image needs updating Reference...

  17. Lower-hybrid poloidal current drive for fluctuation reduction in a reversed field pinch

    SciTech Connect

    Uchimoto, E.; Cekic, M.; Harvey, R.W.; Litwin, C.; Prager, S.C.; Sarff, J.S.; Sovinec, C.R.

    1994-06-01

    Current drive using the lower-hybrid slow wave is shown to be a promising candidate for improving confinement properties of a reversed field pinch (RFP). Ray-tracing calculations indicate that the wave will make a few poloidal turns while spiraling radially into a target zone inside the reversal layer. The poloidal antenna wavelength of the lower hybrid wave can be chosen so that efficient parallel current drive will occur mostly in the poloidal direction in this outer region. Three-dimensional resistive magnetohydrodynamic (MHD) computation demonstrates that an additive poloidal current in this region will reduce the magnetic fluctuations and magnetic stochasticity.

  18. The effect of collisional dissipation on the radial profiles of current

    Office of Scientific and Technical Information (OSTI)

    driven by the lower-hybrid waves (Journal Article) | SciTech Connect The effect of collisional dissipation on the radial profiles of current driven by the lower-hybrid waves Citation Details In-Document Search Title: The effect of collisional dissipation on the radial profiles of current driven by the lower-hybrid waves A simulation of the collisional dissipation of fast electrons has been conducted in lower-hybrid-current drive (LHCD) tokamak plasmas. The simulation results show that the

  19. Surface acoustic wave propagation in graphene film

    SciTech Connect

    Roshchupkin, Dmitry Plotitcyna, Olga; Matveev, Viktor; Kononenko, Oleg; Emelin, Evgenii; Irzhak, Dmitry; Ortega, Luc; Zizak, Ivo; Erko, Alexei; Tynyshtykbayev, Kurbangali; Insepov, Zinetula

    2015-09-14

    Surface acoustic wave (SAW) propagation in a graphene film on the surface of piezoelectric crystals was studied at the BESSY II synchrotron radiation source. Talbot effect enabled the visualization of the SAW propagation on the crystal surface with the graphene film in a real time mode, and high-resolution x-ray diffraction permitted the determination of the SAW amplitude in the graphene/piezoelectric crystal system. The influence of the SAW on the electrical properties of the graphene film was examined. It was shown that the changing of the SAW amplitude enables controlling the magnitude and direction of current in graphene film on the surface of piezoelectric crystals.

  20. Topological horseshoes in travelling waves of discretized nonlinear wave equations

    SciTech Connect

    Chen, Yi-Chiuan; Chen, Shyan-Shiou; Yuan, Juan-Ming

    2014-04-15

    Applying the concept of anti-integrable limit to coupled map lattices originated from space-time discretized nonlinear wave equations, we show that there exist topological horseshoes in the phase space formed by the initial states of travelling wave solutions. In particular, the coupled map lattices display spatio-temporal chaos on the horseshoes.

  1. High-frequency matrix converter with square wave input

    SciTech Connect

    Carr, Joseph Alexander; Balda, Juan Carlos

    2015-03-31

    A device for producing an alternating current output voltage from a high-frequency, square-wave input voltage comprising, high-frequency, square-wave input a matrix converter and a control system. The matrix converter comprises a plurality of electrical switches. The high-frequency input and the matrix converter are electrically connected to each other. The control system is connected to each switch of the matrix converter. The control system is electrically connected to the input of the matrix converter. The control system is configured to operate each electrical switch of the matrix converter converting a high-frequency, square-wave input voltage across the first input port of the matrix converter and the second input port of the matrix converter to an alternating current output voltage at the output of the matrix converter.

  2. Resonance of relativistic electrons with electromagnetic ion cyclotron waves

    SciTech Connect

    Denton, R. E.; Jordanova, V. K.; Bortnik, J.

    2015-06-29

    Relativistic electrons have been thought to more easily resonate with electromagnetic ion cyclotron EMIC waves if the total density is large. We show that, for a particular EMIC mode, this dependence is weak due to the dependence of the wave frequency and wave vector on the density. A significant increase in relativistic electron minimum resonant energy might occur for the H band EMIC mode only for small density, but no changes in parameters significantly decrease the minimum resonant energy from a nominal value. The minimum resonant energy depends most strongly on the thermal velocity associated with the field line motion of the hot ring current protons that drive the instability. High density due to a plasmasphere or plasmaspheric plume could possibly lead to lower minimum resonance energy by causing the He band EMIC mode to be dominant. We demonstrate these points using parameters from a ring current simulation.

  3. Resonance of relativistic electrons with electromagnetic ion cyclotron waves

    DOE PAGES [OSTI]

    Denton, R. E.; Jordanova, V. K.; Bortnik, J.

    2015-06-29

    Relativistic electrons have been thought to more easily resonate with electromagnetic ion cyclotron EMIC waves if the total density is large. We show that, for a particular EMIC mode, this dependence is weak due to the dependence of the wave frequency and wave vector on the density. A significant increase in relativistic electron minimum resonant energy might occur for the H band EMIC mode only for small density, but no changes in parameters significantly decrease the minimum resonant energy from a nominal value. The minimum resonant energy depends most strongly on the thermal velocity associated with the field line motionmore » of the hot ring current protons that drive the instability. High density due to a plasmasphere or plasmaspheric plume could possibly lead to lower minimum resonance energy by causing the He band EMIC mode to be dominant. We demonstrate these points using parameters from a ring current simulation.« less

  4. System and method for generating current by selective minority species heating

    DOEpatents

    Fisch, Nathaniel J.

    1983-01-01

    A system for the generation of toroidal current in a plasma which is prepared in a toroidal magnetic field. The system utilizes the injection of low-frequency waves into the plasma by means of phased antenna arrays or phased waveguide arrays. The plasma is prepared with a minority ion species of different charge state and different gyrofrequency from the majority ion species. The wave frequency and wave phasing are chosen such that the wave energy is absorbed preferentially by minority species ions traveling in one toroidal direction. The absorption of energy in this manner produces a toroidal electric current even when the injected waves themselves do not have substantial toroidal momentum. This current can be continuously maintained at modest cost in power and may be used to confine the plasma. The system can operate efficiently on fusion grade tokamak plasmas.

  5. Ultracapacitor current collector

    DOEpatents

    Jerabek, Elihu Calfin (Glenmont, NY); Mikkor, Mati (Ann Arbor, MI)

    2001-10-16

    An ultracapacitor having two solid, nonporous current collectors, two porous electrodes separating the collectors, a porous separator between the electrodes and an electrolyte occupying the pores in the electrodes and separator. At least one of the current collectors comprises a conductive metal substrate coated with a metal nitride, carbide or boride coating.

  6. Current level detector

    DOEpatents

    Kerns, Cordon R.

    1977-01-01

    A device is provided for detecting the current level of a DC signal. It includes an even harmonic modulator to which a reference AC signal is applied. The unknown DC signal acts on the reference AC signal so that the output of the modulator includes an even harmonic whose amplitude is proportional to the unknown DC current.

  7. Wave energy absorber mountable on wave-facing structure

    SciTech Connect

    Kondo, H.

    1983-09-13

    A wave energy absorber comprising a caisson mountable on the seaside surface of an existing breakwater or coastal embankment, which caisson has a water chamber with an open side and a rear wall facing the open side. The distance from the open side to the rear wall is longer than one quarter of a wavelength L /SUB c/ in the water chamber so as to generate a standing wave in the water chamber with a node of the standing wave at a distance L /SUB c/ /4 from the rear wall toward the open side. A wave power turbine impeller is pivotally supported in the caisson at the node position, the impeller rotating in only one direction, whereby wave energy is absorbed by the impeller for further conversion into electric or thermal energy. The caisson itself can also be utilized as a breakwater or an embankment.

  8. Marine pipeline dynamic response to waves from directional wave spectra

    SciTech Connect

    Lambrakos, K.F.

    1982-07-01

    A methodology has been developed to calculate the dynamic probabilistic movement and resulting stresses for marine pipelines subjected to storm waves. A directional wave spectrum is used with a Fourier series expansion to simulate short-crested waves and calculate their loads on the pipeline. The pipeline displacements resulting from these loads are solutions to the time-dependent beam-column equation which also includes the soil resistance as external loading. The statistics of the displacements for individual waves are combined with the wave statistics for a given period of time, e.g. pipeline lifetime, to generate probabilistic estimates for net pipeline movement. On the basis of displacements for specified probability levels the pipeline configuration is obtained from which pipeline stresses can be estimated using structural considerations, e.g. pipeline stiffness, end restraints, etc.

  9. Interaction of ICRF waves with lower-hybrid driven suprathermal electrons

    SciTech Connect

    Ram, A.K.; Bers, A. ); Fuchs, V. ); Harvey, R.W. )

    1994-10-15

    We determine the conditions for which the interaction of mode converted ion-Bernstein waves (IBW) with the energetic electron tails created by lower hybrid waves (LHW) can lead to an enhancement in the current drive efficiency. This may help explain the synergy'' results obtained on JET.

  10. Voltage controlled current source

    DOEpatents

    Casne, Gregory M.

    1992-01-01

    A seven decade, voltage controlled current source is described for use in testing intermediate range nuclear instruments that covers the entire test current range of from 10 picoamperes to 100 microamperes. High accuracy is obtained throughout the entire seven decades of output current with circuitry that includes a coordinated switching scheme responsive to the input signal from a hybrid computer to control the input voltage to an antilog amplifier, and to selectively connect a resistance to the antilog amplifier output to provide a continuous output current source as a function of a preset range of input voltage. An operator controlled switch provides current adjustment for operation in either a real-time simulation test mode or a time response test mode.

  11. Superconducting current transducer

    SciTech Connect

    Kuchnir, M.; Ozelis, J.P. )

    1991-03-01

    This paper describes the construction and performance of an electric current meter that operates in liquid He and mechanically splits apart to permit replacement of the current carrying conductor. It permits the measurement of currents induced in a loop of superconducting cable and expeditious exchange of such loops. It is a key component for a short sample cable testing facility that requires no high current power supplies nor high current leads. Its superconducting pickup circuit involves a non-magnetic core toroidal split-coil that surrounds the conductor and a solenoid whose field is sensed by a Hall probe. This toroidal split-coil is potted inside another compensating toroidal split-coil.

  12. Relativistic electron scattering by magnetosonic waves: Effects of discrete wave emission and high wave amplitudes

    SciTech Connect

    Artemyev, A. V.; Mourenas, D.; Krasnoselskikh, V. V.

    2015-06-15

    In this paper, we study relativistic electron scattering by fast magnetosonic waves. We compare results of test particle simulations and the quasi-linear theory for different spectra of waves to investigate how a fine structure of the wave emission can influence electron resonant scattering. We show that for a realistically wide distribution of wave normal angles θ (i.e., when the dispersion δθ≥0.5{sup °}), relativistic electron scattering is similar for a wide wave spectrum and for a spectrum consisting in well-separated ion cyclotron harmonics. Comparisons of test particle simulations with quasi-linear theory show that for δθ>0.5{sup °}, the quasi-linear approximation describes resonant scattering correctly for a large enough plasma frequency. For a very narrow θ distribution (when δθ∼0.05{sup °}), however, the effect of a fine structure in the wave spectrum becomes important. In this case, quasi-linear theory clearly fails in describing accurately electron scattering by fast magnetosonic waves. We also study the effect of high wave amplitudes on relativistic electron scattering. For typical conditions in the earth's radiation belts, the quasi-linear approximation cannot accurately describe electron scattering for waves with averaged amplitudes >300 pT. We discuss various applications of the obtained results for modeling electron dynamics in the radiation belts and in the Earth's magnetotail.

  13. A continuum of H- to He-rich tidal disruption candidates with a preference for E+A galaxies

    SciTech Connect

    Arcavi, Iair; Gal-Yam, Avishay; Horesh, Assaf; Ofek, Eran O.; De Cia, Annalisa; Tal, David; Sullivan, Mark; Pan, Yen-Chen; Cenko, S. Bradley; Yan, Lin; Yang, Chen-Wei; Howell, D. A.; Kulkarni, Shrinivas R.; Tendulkar, Shriharsh P.; Cohen, Judith G.; Tang, Sumin; Xu, Dong; Sternberg, Assaf; Bloom, Joshua S.; Nugent, Peter E.; and others

    2014-09-20

    We present the results of a Palomar Transient Factory (PTF) archival search for blue transients that lie in the magnitude range between 'normal' core-collapse and superluminous supernovae (i.e., with –21 ≤ M {sub R} {sub (peak)} ≤ – 19). Of the six events found after excluding all interacting Type IIn and Ia-CSM supernovae, three (PTF09ge, 09axc, and 09djl) are coincident with the centers of their hosts, one (10iam) is offset from the center, and a precise offset cannot be determined for two (10nuj and 11glr). All the central events have similar rise times to the He-rich tidal disruption candidate PS1-10jh, and the event with the best-sampled light curve also has similar colors and power-law decay. Spectroscopically, PTF09ge is He-rich, while PTF09axc and 09djl display broad hydrogen features around peak magnitude. All three central events are in low star formation hosts, two of which are E+A galaxies. Our spectrum of the host of PS1-10jh displays similar properties. PTF10iam, the one offset event, is different photometrically and spectroscopically from the central events, and its host displays a higher star formation rate. Finding no obvious evidence for ongoing galactic nuclei activity or recent star formation, we conclude that the three central transients likely arise from the tidal disruption of a star by a supermassive black hole. We compare the spectra of these events to tidal disruption candidates from the literature and find that all of these objects can be unified on a continuous scale of spectral properties. The accumulated evidence of this expanded sample strongly supports a tidal disruption origin for this class of nuclear transients.

  14. Using AORSA to simulate helicon waves in DIII-D

    SciTech Connect

    Lau, Cornwall H; Jaeger, E. F.; Bertelli, Nicola; Berry, Lee Alan; Blazevski, Dan; Green, David L; Murakami, Masanori; Park, J. M.; Pinsker, R. I.; Prater, R.

    2015-01-01

    Recent efforts have shown that helicon waves (fast waves at >20 omega(ci)) may be an attractive option for driving efficient off-axis current drive during non-inductive tokamak operation for DIII-D, ITER and DEMO. For DIII-D scenarios, the ray tracing code, GENRAY, has been extensively used to study helicon current drive efficiency and location as a function of many plasma parameters. The full wave code, AORSA, which is applicable to arbitrary Larmor radius and can resolve arbitrary ion cyclotron harmonic order, has been recently used to validate the ray tracing technique at these high cyclotron harmonics. If the SOL is ignored, it will be shown that the GENRAY and AORSA calculated current drive profiles are comparable for the envisioned high beta advanced scenarios for DIII-D, where there is high single pass absorption due to electron Landau damping and minimal ion damping. AORSA is also been used to estimate possible SOL effects on helicon current drive coupling and SOL absorption due to collisional and slow wave effects.

  15. Using AORSA to simulate helicon waves in DIII-D

    SciTech Connect

    Lau, C. Blazevski, D.; Green, D. L.; Murakami, M.; Park, J. M.; Jaeger, E. F.; Berry, L. A.; Bertelli, N.; Pinsker, R. I.; Prater, R.

    2015-12-10

    Recent efforts have shown that helicon waves (fast waves at > 20ω{sub ci}) may be an attractive option for driving efficient off-axis current drive during non-inductive tokamak operation for DIII-D, ITER and DEMO. For DIII-D scenarios, the ray tracing code, GENRAY, has been extensively used to study helicon current drive efficiency and location as a function of many plasma parameters. The full wave code, AORSA, which is applicable to arbitrary Larmor radius and can resolve arbitrary ion cyclotron harmonic order, has been recently used to validate the ray tracing technique at these high cyclotron harmonics. If the SOL is ignored, it will be shown that the GENRAY and AORSA calculated current drive profiles are comparable for the envisioned high beta advanced scenarios for DIII-D, where there is high single pass absorption due to electron Landau damping and minimal ion damping. AORSA is also been used to estimate possible SOL effects on helicon current drive coupling and SOL absorption due to collisional and slow wave effects.

  16. Full wave simulations of fast wave heating losses in the scrape...

    Office of Scientific and Technical Information (OSTI)

    Full wave simulations of fast wave heating losses in the scrape-off layer of NSTX and NSTX-U Citation Details In-Document Search Title: Full wave simulations of fast wave heating...

  17. Tidally distorted exoplanets: Density corrections for short-period hot-Jupiters based solely on observable parameters

    SciTech Connect

    Burton, J. R.; Watson, C. A.; Fitzsimmons, A.; Moulds, V.; Pollacco, D.; Wheatley, P. J.; Littlefair, S. P.

    2014-07-10

    The close proximity of short-period hot-Jupiters to their parent star means they are subject to extreme tidal forces. This has a profound effect on their structure and, as a result, density measurements that assume that the planet is spherical can be incorrect. We have simulated the tidally distorted surface for 34 known short-period hot-Jupiters, assuming surfaces of constant gravitational equipotential for the planet, and the resulting densities have been calculated based only on observed parameters of the exoplanet systems. Comparing these results to the density values, assuming the planets are spherical, shows that there is an appreciable change in the measured density for planets with very short periods (typically less than two days). For one of the shortest-period systems, WASP-19b, we determine a decrease in bulk density of 12% from the spherical case and, for the majority of systems in this study, this value is in the range of 1%-5%. On the other hand, we also find cases where the distortion is negligible (relative to the measurement errors on the planetary parameters) even in the cases of some very short period systems, depending on the mass ratio and planetary radius. For high-density gas planets requiring apparently anomalously large core masses, density corrections due to tidal deformation could become important for the shortest-period systems.

  18. Compressive passive millimeter wave imager

    DOEpatents

    Gopalsami, Nachappa; Liao, Shaolin; Elmer, Thomas W; Koehl, Eugene R; Heifetz, Alexander; Raptis, Apostolos C

    2015-01-27

    A compressive scanning approach for millimeter wave imaging and sensing. A Hadamard mask is positioned to receive millimeter waves from an object to be imaged. A subset of the full set of Hadamard acquisitions is sampled. The subset is used to reconstruct an image representing the object.

  19. TURBOVELOCITY STARS: KICKS RESULTING FROM THE TIDAL DISRUPTION OF SOLITARY STARS

    SciTech Connect

    Manukian, Haik; Guillochon, James; Ramirez-Ruiz, Enrico; O'Leary, Ryan M.

    2013-07-10

    The centers of most known galaxies host supermassive black holes (SMBHs). In orbit around these black holes are a centrally concentrated distribution of stars, both in single and in binary systems. Occasionally, these stars are perturbed onto orbits that bring them close to the SMBH. If the star is in a binary system, the three-body interaction with the SMBH can lead to large changes in orbital energy, depositing one of the two stars on a tightly-bound orbit, and its companion into a hyperbolic orbit that may escape the galaxy. In this Letter, we show that the disruption of solitary stars can also lead to large positive increases in orbital energy. The kick velocity depends on the amount of mass the star loses at pericenter, but not on the ratio of black hole to stellar mass, and are at most the star's own escape velocity. We find that these kicks are usually too small to result in the ejection of stars from the Milky Way, but can eject the stars from the black hole's sphere of influence, reducing their probability of being disrupted again. We estimate that {approx} 10{sup 5} stars, {approx} 1% of all stars within 10 pc of the galactic center, are likely to have had mass removed by the central black hole through tidal interaction, and speculate that these 'turbovelocity' stars will at first be redder, but eventually bluer, and always brighter than their unharassed peers.

  20. Hyperaccretion during tidal disruption events: Weakly bound debris envelopes and jets

    SciTech Connect

    Coughlin, Eric R.; Begelman, Mitchell C. E-mail: mitch@jila.colorado.edu

    2014-02-01

    After the destruction of the star during a tidal disruption event (TDE), the cataclysmic encounter between a star and the supermassive black hole (SMBH) of a galaxy, approximately half of the original stellar debris falls back onto the hole at a rate that can initially exceed the Eddington limit by orders of magnitude. We argue that the angular momentum of this matter is too low to allow it to attain a disk-like configuration with accretion proceeding at a mildly super-Eddington rate, the excess energy being carried away by a combination of radiative losses and radially distributed winds. Instead, we propose that the infalling gas traps accretion energy until it inflates into a weakly bound, quasi-spherical structure with gas extending nearly to the poles. We study the structure and evolution of such 'zero-Bernoulli accretion' flows as a model for the super-Eddington phase of TDEs. We argue that such flows cannot stop extremely super-Eddington accretion from occurring, and that once the envelope is maximally inflated, any excess accretion energy escapes through the poles in the form of powerful jets. We compare the predictions of our model to Swift J1644+57, the putative super-Eddington TDE, and show that it can qualitatively reproduce some of its observed features. Similar models, including self-gravity, could be applicable to gamma-ray bursts from collapsars and the growth of SMBH seeds inside quasi-stars.

  1. A new feedback controlled current stabilized power supply for gas laser

    SciTech Connect

    Not Available

    1981-11-01

    A feedback controlled current stabilized power supply for CO/sub 2/, wave guide lasers is reported. This current negative feedback control method involved connecting the control transistor to the DC output and of an AC bridge rectifier. Current is stabilized in the range of 2 to approximately 4 mW, the unstability of the current is less than 1% with respect to 20% fluctuation of network voltage. The principal circuit and the voltage-current wave forms of the power supply are shown.

  2. Tube-wave seismic imaging

    DOEpatents

    Korneev, Valeri A.; Bakulin, Andrey

    2009-10-13

    The detailed analysis of cross well seismic data for a gas reservoir in Texas revealed two newly detected seismic wave effects, recorded approximately 2000 feet above the reservoir. A tube-wave (150) is initiated in a source well (110) by a source (111), travels in the source well (110), is coupled to a geological feature (140), propagates (151) through the geological feature (140), is coupled back to a tube-wave (152) at a receiver well (120), and is and received by receiver(s) (121) in either the same (110) or a different receiving well (120). The tube-wave has been shown to be extremely sensitive to changes in reservoir characteristics. Tube-waves appear to couple most effectively to reservoirs where the well casing is perforated, allowing direct fluid contact from the interior of a well case to the reservoir.

  3. Tube-wave seismic imaging

    DOEpatents

    Korneev, Valeri A [LaFayette, CA

    2009-05-05

    The detailed analysis of cross well seismic data for a gas reservoir in Texas revealed two newly detected seismic wave effects, recorded approximately 2000 feet above the reservoir. A tube-wave (150) is initiated in a source well (110) by a source (111), travels in the source well (110), is coupled to a geological feature (140), propagates (151) through the geological feature (140), is coupled back to a tube-wave (152) at a receiver well (120), and is and received by receiver(s) (121) in either the same (110) or a different receiving well (120). The tube-wave has been shown to be extremely sensitive to changes in reservoir characteristics. Tube-waves appear to couple most effectively to reservoirs where the well casing is perforated, allowing direct fluid contact from the interior of a well case to the reservoir.

  4. Integrated coherent matter wave circuits

    DOE PAGES [OSTI]

    Ryu, C.; Boshier, M. G.

    2015-09-21

    An integrated coherent matter wave circuit is a single device, analogous to an integrated optical circuit, in which coherent de Broglie waves are created and then launched into waveguides where they can be switched, divided, recombined, and detected as they propagate. Applications of such circuits include guided atom interferometers, atomtronic circuits, and precisely controlled delivery of atoms. We report experiments demonstrating integrated circuits for guided coherent matter waves. The circuit elements are created with the painted potential technique, a form of time-averaged optical dipole potential in which a rapidly moving, tightly focused laser beam exerts forces on atoms through theirmoreelectric polarizability. Moreover, the source of coherent matter waves is a BoseEinstein condensate (BEC). Finally, we launch BECs into painted waveguides that guide them around bends and form switches, phase coherent beamsplitters, and closed circuits. These are the basic elements that are needed to engineer arbitrarily complex matter wave circuitry.less

  5. MHK Technologies/C Wave | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    homepage C Wave.jpg Technology Profile Primary Organization C Wave Technology Resource Click here Wave Technology Type Click here Attenuator Technology Description The C Wave...

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

    OpenEI (Open Energy Information) [EERE & EIA]

    Wave Coordinates 46.53, -55.4 Project Phase Phase 3 Project Details Although SARAHS Pump is still in the development stage, a prototype sea trial test is currently ongoing....

  7. Current Annualized Request

    Office of Environmental Management (EM)

    Organization FY 2012 FY 2013 FY 2014 Current Annualized Request CR % National Security Weapons Activities* 7,214,834 7,557,342 7,868,409 +311,067 +4.1% Defense Nuclear...

  8. Current Financial Opportunities

    Energy.gov [DOE]

    Current hydrogen-related funding opportunities through the U.S. Department of Energy's (DOE) Fuel Cell Technologies Office are listed below. The Fuel Cell Technologies Office offers opportunities for both financial and technical assistance.

  9. Current control circuitry

    DOEpatents

    Taubman, Matthew S.

    2005-03-15

    Among the embodiments of the present invention is an apparatus that includes a transistor (30), a servo device (40), and a current source (50). The servo device (40) is operable to provide a common base mode of operation of the transistor (30) by maintaining an approximately constant voltage level at the transistor base (32b). The current source (150) is operable to provide a bias current to the transistor (30). A first device (24) provides an input signal to an electrical node (70) positioned between the emitter (32e) of the transistor (30) and the current source (50). A second device (26) receives an output signal from the collector (32c) of the transistor (30).

  10. CURRENT TRANSFER SYSTEMS

    DOEpatents

    Watt, D.A.

    1956-07-01

    A current transfer system is described for transferring current between a rotating member and a co-axial stationary member. The particular area of application for the invention is in connection with homopolar generators where a low voltage and high current are generated. The current tramsfer system of the invention comprises a rotor member and a co-axial stator member wherein one of the members is shaped to provide a circumferential surface concave in section and the other member is shaped to have a peripheral portion in close proximity to the surface, whereby a liquid metal can be stably supported between the two members when they are moving relative to one another to establish an electrical conducting path between the members.

  11. Geothermal Energy: Current abstracts

    SciTech Connect

    Ringe, A.C.

    1988-02-01

    This bulletin announces the current worldwide information available on the technologies required for economic recovery of geothermal energy and its use as direct heat or for electric power production. (ACR)

  12. Current Testbed Research

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Current Testbed Research Network R&D Software-Defined Networking (SDN) Experimental Network Testbeds 100G SDN Testbed Dark Fiber Testbed Test Circuit Service Testbed Results Current Testbed Research Previous Testbed Research Performance (perfSONAR) Software & Tools Development Data for Researchers Partnerships Publications Workshops Contact Us Technical Assistance: 1 800-33-ESnet (Inside US) 1 800-333-7638 (Inside US) 1 510-486-7600 (Globally) 1 510-486-7607 (Globally) Report Network

  13. Method and apparatus for actively controlling a micro-scale flexural plate wave device

    DOEpatents

    Dohner, Jeffrey L.

    2001-01-01

    An actively controlled flexural plate wave device provides a micro-scale pump. A method of actively controlling a flexural plate wave device produces traveling waves in the device by coordinating the interaction of a magnetic field with actively controlled currents. An actively-controlled flexural plate wave device can be placed in a fluid channel and adapted for use as a micro-scale fluid pump to cool or drive micro-scale systems, for example, micro-chips, micro-electrical-mechanical devices, micro-fluid circuits, or micro-scale chemical analysis devices.

  14. Deployment Effects of Marine Renewable Energy Technologies: Wave Energy Scenarios

    SciTech Connect

    Mirko Previsic

    2010-06-17

    Given proper care in siting, design, deployment, operation and maintenance, wave energy conversion could become one of the more environmentally benign sources of electricity generation. In order to accelerate the adoption of these emerging hydrokinetic and marine energy technologies, navigational and environmental concerns must be identified and addressed. All developing hydrokinetic projects involve a wide variety of stakeholders. One of the key issues that site developers face as they engage with this range of stakeholders is that, due to a lack of technical certainty, many of the possible conflicts (e.g., shipping and fishing) and environmental issues are not well-understood,. In September 2008, re vision consulting, LLC was selected by the Department of Energy (DoE) to apply a scenario-based assessment to the emerging hydrokinetic technology sector in order to evaluate the potential impact of these technologies on the marine environment and navigation constraints. The project’s scope of work includes the establishment of baseline scenarios for wave and tidal power conversion at potential future deployment sites. The scenarios capture variations in technical approaches and deployment scales to properly identify and characterize environmental effects and navigational effects. The goal of the project is to provide all stakeholders with an improved understanding of the potential range of technical attributes and potential effects of these emerging technologies and focus all stakeholders on the critical issues that need to be addressed. By identifying and addressing navigational and environmental concerns in the early stages of the industry’s development, serious mistakes that could potentially derail industry-wide development can be avoided. This groundwork will also help in streamlining siting and associated permitting processes, which are considered key hurdles for the industry’s development in the U.S. today. Re vision is coordinating its efforts with two

  15. C Wave Ltd | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Ltd Jump to: navigation, search Name: C-Wave Ltd Place: England, United Kingdom Zip: SO17 1BJ Product: C-Wave is developing an innovative wave power technology using a unique...

  16. Beam current sensor

    DOEpatents

    Kuchnir, M.; Mills, F.E.

    1984-09-28

    A current sensor for measuring the dc component of a beam of charged particles employs a superconducting pick-up loop probe, with twisted superconducting leads in combination with a Superconducting Quantum Interference Device (SQUID) detector. The pick-up probe is in the form of a single-turn loop, or a cylindrical toroid, through which the beam is directed and within which a first magnetic flux is excluded by the Meisner effect. The SQUID detector acts as a flux-to-voltage converter in providing a current to the pick-up loop so as to establish a second magnetic flux within the electrode which nulls out the first magnetic flux. A feedback voltage within the SQUID detector represents the beam current of the particles which transit the pick-up loop. Meisner effect currents prevent changes in the magnetic field within the toroidal pick-up loop and produce a current signal independent of the beam's cross-section and its position within the toroid, while the combination of superconducting elements provides current measurement sensitivities in the nano-ampere range.

  17. Beam current sensor

    DOEpatents

    Kuchnir, Moyses; Mills, Frederick E.

    1987-01-01

    A current sensor for measuring the DC component of a beam of charged particles employs a superconducting pick-up loop probe, with twisted superconducting leads in combination with a Superconducting Quantum Interference Device (SQUID) detector. The pick-up probe is in the form of a single-turn loop, or a cylindrical toroid, through which the beam is directed and within which a first magnetic flux is excluded by the Meisner effect. The SQUID detector acts as a flux-to-voltage converter in providing a current to the pick-up loop so as to establish a second magnetic flux within the electrode which nulls out the first magnetic flux. A feedback voltage within the SQUID detector represents the beam current of the particles which transit the pick-up loop. Meisner effect currents prevent changes in the magnetic field within the toroidal pick-up loop and produce a current signal independent of the beam's cross-section and its position within the toroid, while the combination of superconducting elements provides current measurement sensitivites in the nano-ampere range.

  18. Superconducting current transducer

    SciTech Connect

    Kuchnir, M.; Ozelis, J.P.

    1990-10-01

    The construction and performance of an electric current meter that operates in liquid He and mechanically splits apart to permit replacement of the current carrying conductor is described. It permits the measurement of currents induced in a loop of superconducting cable and expeditious exchange of such loops. It is a key component for a short sample cable testing facility that requires no high current power supplies nor high current leads. Its superconducting pickup circuit involves a non-magnetic core toroidal split-coil that surrounds the conductor and a solenoid whose field is sensed by a Hall probe. This toroidal split-coil is potted inside another compensating toroidal split-coil. The C shaped half toroids can be separated and brought precisely together from outside the cryostat. The Hall probe is energized and sensed by a lock-in amplifier whose output drives a bipolar power supply which feeds the compensating coil. The output is the voltage across a resistor in this feedback circuit. Currents of up to 10 kA can be measured with a precision of 150 mA. 3 refs., 4 figs.

  19. Nonlinear Alfvén wave dynamics in plasmas

    SciTech Connect

    Sarkar, Anwesa; Chakrabarti, Nikhil

    2015-07-15

    Nonlinear Alfvén wave dynamics is presented using Lagrangian fluid approach in a compressible collisional magnetized plasma. In the framework of two fluid dynamics, finite electron inertia is shown to serve as a dispersive effect acting against the convective nonlinearity. In a moving frame, the Alfvén wave can, therefore, form an arbitrarily strong amplitude solitary wave structure due to the balance between nonlinearity and dispersion. Weak amplitude Alfvén waves are shown to be governed by a modified KdV equation, which extends for finite dissipation to a mKdV-Burgers equation. These equations have well known solutions. Next, we have analyzed the fourth order nonlinear Alfvén wave system of equations both numerically and by approximation method. The results indicate a collapse of the density and magnetic field irrespective of the presence of dispersion. The wave magnetic field, however, appears to be less singular showing collapse only when the dispersive effects are negligible. These results may contribute to our understanding of the generation of strongly localized magnetic fields (and currents) in plasmas and are expected to be of special importance in the astrophysical context of magnetic star formation.

  20. Optimization of High-order Wave Equations for Multicore CPUs

    Energy Science and Technology Software Center

    2011-11-01

    This is a simple benchmark to guage the performance of a high-order isotropic wave equation grid. The code is optimized for both SSE and AVX and is parallelized using OpenMP (see Optimization section). Structurally, the benchmark begins, reads a few command-line parameters, allocates and pads the four arrays (current, last, next wave fields, and the spatially varying but isotropic velocity), initializes these arrays, then runs the benchmark proper. The code then benchmarks the naive, SSEmore » (if supported), and AVX (if supported implementations) by applying the wave equation stencil 100 times and taking the average performance. Boundary conditions are ignored and would noiminally be implemented by the user. THus, the benchmark measures only the performance of the wave equation stencil and not a full simulation. The naive implementation is a quadruply (z,y,x, radius) nested loop that can handle arbitrarily order wave equations. The optimized (SSE/AVX) implentations are somewhat more complex as they operate on slabs and include a case statement to select an optimized inner loop depending on wave equation order.« less

  1. Adjustable direct current and pulsed circuit fault current limiter

    DOEpatents

    Boenig, Heinrich J.; Schillig, Josef B.

    2003-09-23

    A fault current limiting system for direct current circuits and for pulsed power circuit. In the circuits, a current source biases a diode that is in series with the circuits' transmission line. If fault current in a circuit exceeds current from the current source biasing the diode open, the diode will cease conducting and route the fault current through the current source and an inductor. This limits the rate of rise and the peak value of the fault current.

  2. Coupling of α-channeling to |k∥| upshift in lower hybrid current drive

    SciTech Connect

    Ochs, I. E.; Bertelli, N.; Fisch, N. J.

    2014-08-26

    Although lower hybrid waves have been shown to be effective in driving plasma current in present-day tokamaks, they are predicted to strongly interact with the energetic α particles born from fusion reactions in eventual tokamak reactors.

  3. Dichromatic Langmuir waves in degenerate quantum plasma

    SciTech Connect

    Dubinov, A. E. Kitayev, I. N.

    2015-06-15

    Langmuir waves in fully degenerate quantum plasma are considered. It is shown that, in the linear approximation, Langmuir waves are always dichromatic. The low-frequency component of the waves corresponds to classical Langmuir waves, while the high-frequency component, to free-electron quantum oscillations. The nonlinear problem on the profile of dichromatic Langmuir waves is solved. Solutions in the form of a superposition of waves and in the form of beatings of its components are obtained.

  4. Kinetic Wave Power | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Wave Power Jump to: navigation, search Name: Kinetic Wave Power Address: 2861 N Tupelo St Place: Midland Zip: 48642 Region: United States Sector: Marine and Hydrokinetic Phone...

  5. Triton Sea Wave Technologies | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Triton Sea Wave Technologies Jump to: navigation, search Name: Triton Sea Wave Technologies Address: 22 A Thrakis Zip: 15669 Region: Greece Sector: Marine and Hydrokinetic Year...

  6. Clean Wave Ventures | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Wave Ventures Jump to: navigation, search Name: Clean Wave Ventures Place: Indianapolis, Indiana Zip: 46204 Product: Midwest-based venture capital firm specializing in high growth...

  7. Euro Wave Energy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Wave Energy Jump to: navigation, search Name: Euro Wave Energy Region: Norway Sector: Marine and Hydrokinetic Website: www.eurowaveenergy.com This company is listed in the Marine...

  8. Dartmouth Wave Energy Searaser | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Energy Searaser Jump to: navigation, search Name: Dartmouth Wave Energy (Searaser) Place: United Kingdom Product: British firm developing the wave energy converter, Searaser....

  9. Leancon Wave Energy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Leancon Wave Energy Jump to: navigation, search Name: Leancon Wave Energy Address: Alpedalsvej 37 Place: Kolding Zip: 6000 Region: Denmark Sector: Marine and Hydrokinetic Phone...

  10. Green Ocean Wave Energy | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Ocean Wave Energy Jump to: navigation, search Name: Green Ocean Wave Energy Region: United States Sector: Marine and Hydrokinetic Website: http: This company is listed in the...

  11. Wave Energy Basics | Department of Energy

    Office of Energy Efficiency and Renewable Energy (EERE) (indexed site)

    Ocean » Wave Energy Basics Wave Energy Basics August 16, 2013 - 4:30pm Addthis Photo of a large wave. Wave energy technologies extract energy directly from surface waves or from pressure fluctuations below the surface. Renewable energy analysts believe there is enough energy in ocean waves to provide up to 2 terawatts of electricity. (A terawatt is equal to a trillion watts.) However, wave energy cannot be harnessed everywhere. Wave power-rich areas of the world include the western coasts of

  12. Millimeter Wave Sensor Technologies Track Biometrics; Detect...

    U.S. Department of Energy (DOE) - all webpages (Extended Search)

    Argonne's millimeter wave (mmW) sensor technologies measure a wide range of threat ... Argonne's millimeter wave (mmW) sensor technologies measure a wide range of threat ...

  13. Wave Wind LLC | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Wave Wind LLC Jump to: navigation, search Name: Wave Wind LLC Place: Sun Prairie, Wisconsin Zip: 53590 Sector: Services, Wind energy Product: Wisconsin-based wind developer and...

  14. Wind Waves and Sun | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Wind Waves and Sun Jump to: navigation, search Name: Wind Waves and Sun Region: United States Sector: Marine and Hydrokinetic Website: www.windwavesandsun.com This company is...

  15. Motor Wave Group | Open Energy Information

    OpenEI (Open Energy Information) [EERE & EIA]

    Wave Group Jump to: navigation, search Name: Motor Wave Group Place: Hong Kong Region: China Sector: Marine and Hydrokinetic Website: www.motorwavegroup.com This company is listed...

  16. Mutual inductance current transducer

    SciTech Connect

    Hemminger, R.C.

    1989-12-12

    This patent describes a mutual inductance differential current transducer for producing an analog voltage output signal in response to, and having a level varying linearly with respect to, and having a level varying linearly with respect to, the magnitude and rate of change of a flow of current supplied by an alternating current power line distribution system. It comprises: an elongated current conductor having first and second ends and a substantially straight axial portion therebetween of a predetermined length and defining a central axis; a generally cylindrical sleeve of conductive material of substantially the predetermined length, received coaxially over the elongated current conductor in the straight axial portion thereof and electrically insulated therefrom; a toroidal sensor coil defining a central axis and having an axial length less than approximately one-third the length of the generally cylindrical sleeve and an internal diameter substantially the same as the outer diameter of the cylindrical sleeve and sufficient to position the coil coaxially on the cylindrical sleeve. The coil being positioned coaxially thereon and generally centrally of the length thereof.

  17. Recirculation in multiple wave conversions

    SciTech Connect

    Kaufman, A. N.; Brizard, A.J.; Kaufman, A.N.; Tracy, E.R.

    2008-07-30

    A one-dimensional multiple wave-conversion model is constructed that allows energy recirculation in ray phase space. Using a modular eikonal approach, the connection coefficients for this model are calculated by ray phase-space methods. Analytical results (confirmed numerically) show that all connection coefficients exhibit interference effects that depend on an interference phase, calculated from the coupling constants and the area enclosed by the intersecting rays. This conceptual model, which focuses on the topology of intersecting rays in phase space, is used to investigate how mode conversion between primary and secondary waves is modified by the presence of a tertiary wave.

  18. Mode conversion and absorption of fast waves at high ion cyclotron harmonics in inhomogeneous magnetic fields

    SciTech Connect

    Cho, Suwon; Kwak, Jong-Gu

    2014-04-15

    The propagation and absorption of high harmonic fast waves is of interest for non-inductive current drives in fusion experiments. The fast wave can be coupled with the ion Bernstein wave that propagates in the high magnetic field side of an ion cyclotron harmonic resonance layer. This coupling and the absorption are analyzed using the hot plasma dispersion relation and a wave equation that was converted from an approximate dispersion relation for the case where λ{sub i}=k{sub ⊥}{sup 2}ρ{sub i}{sup 2}/2≳1 (where k{sub ⊥} is the perpendicular wave number and ρ{sub i} is the ion Larmor radius). It is found that both reflection and conversion may occur near the harmonic resonance layer but that they decrease rapidly, giving rise to a sharp increase in the absorption as the parallel wave number increases.

  19. Coastal ocean current response to storm winds

    SciTech Connect

    Gordon, R.L.

    1982-03-20

    Design of offshore structures requires knowledge of the appropriate current profile to be used in conjunction with the design wave. Accurate determination of the current profile will depend on reliable current models. Vertical transfer of momentum in storm-driven current models is commonly treated either by using eddy viscosity or by assuming 'slab-like' mixed layer flow. These two fundamentally different approaches predict different current speeds and profiles during severe storms. The existing data base is inadequate to determine which approach is better, but most existing data sets are subject to one or more of four limitations that can lead one improperly to interpret the data as supporting the existence of current velocity shear in otherwise uniform mixed layers. One-dimensional slab models are found to compare favorably with observed wind-driven currents at the Ocean Test Structure in the Gulf of Mexico (deployed in 20 m deep water). By using some reasonably simple assumptions, these slab models are able to replicate many of the significantly features of the wide range of different responses. The character of the response appears to depend on an interaction of stratification and topography. Barotropic responses are characteristic of typical coastal responses; current oriented longshore and are in phase with the wind. Baroclinic responses are dominantly inertial as might be expected in the deep sea, but with an additional near-bottom cross-shore counter flow. The structure of one observed barotropic response is compared to detail to predictions of both slab and eddy viscosity models and found consistent with a slab model and inconsistent with eddy viscosity models. Shear observed during this event was not significantly different from zero, but was significantly below estimated shear predictions of four eddy viscosity models given the peak 0.4 N/m/sup 2/ wind stress.

  20. FAST ACTING CURRENT SWITCH

    DOEpatents

    Batzer, T.H.; Cummings, D.B.; Ryan, J.F.

    1962-05-22

    A high-current, fast-acting switch is designed for utilization as a crowbar switch in a high-current circuit such as used to generate the magnetic confinement field of a plasma-confining and heat device, e.g., Pyrotron. The device particularly comprises a cylindrical housing containing two stationary, cylindrical contacts between which a movable contact is bridged to close the switch. The movable contact is actuated by a differential-pressure, airdriven piston assembly also within the housing. To absorb the acceleration (and the shock imparted to the device by the rapidly driven, movable contact), an adjustable air buffer assembly is provided, integrally connected to the movable contact and piston assembly. Various safety locks and circuit-synchronizing means are also provided to permit proper cooperation of the invention and the high-current circuit in which it is installed. (AEC)