Sample records for wave energy power

  1. Power conversion mechanisms for wave energy

    Microsoft Academic Search

    S H Salter; J R M Taylor; N J Caldwell

    2002-01-01

    It is easy to make a device that will respond vigorously to the action of sea waves. Indeed, it is quite hard to make one that will not. However, the conversion of the slow, random, reversing energy flows with very high extreme values into phase-locked synchronous electricity with power quality acceptable to a utility network is very much harder. This

  2. Wave energy converters and their impact on power systems

    Microsoft Academic Search

    Henk Polinder; Mattia Scuotto

    2005-01-01

    The objective of this paper is to give an introduction into ocean wave energy converters and their impact on power systems. The potential of wave energy is very large. There are a lot of different methods and systems for converting this power into electrical power, such as oscillating water columns, hinged contour devices as the Pelamis, overtopping devices as the

  3. Study on a wave energy based power system

    Microsoft Academic Search

    Loránd SZABÓ; Claudiu OPREA; C. Festila; E. Dulf

    2008-01-01

    Huge quantities of clean energy can be obtained from the waves of the oceans and seas. As wave energy extraction technology is currently in a preliminary state of development any new results in this field should be of real interest. A direct driven wave power conversion system to be placed in the Black Sea near the Romania shores was proposed

  4. Devices for extracting energy from wave power

    SciTech Connect

    Moody, G.W.; Salter, S.H.; Wilson, J.L.

    1980-04-22

    The invention provides a device for extracting energy from waves on a liquid, the device having a chamber with an opening for the flow of liquid into and out of the chamber to provide a quantity of the liquid which is arranged to oscillate in the chamber to provide energy from these oscillations. In order to maximize the energy absorption efficiency of the device, that portion of the device to be submerged and lie in a vertical plane aligned in the direction of propagation of the waves is of asymmetric shape, and the device is arranged to be held in a manner to inhibit movement of the device itself in response to the waves.

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

    SciTech Connect

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

    2012-10-29

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

  6. Power inversion design for ocean wave energy harvesting

    NASA Astrophysics Data System (ADS)

    Talebani, Anwar N.

    The needs for energy sources are increasing day by day because of several factors, such as oil depletion, and global climate change due to the higher level of CO2, so the exploration of various renewable energy sources is very promising area of study. The available ocean waves can be utilized as free source of energy as the water covers 70% of the earth surface. This thesis presents the ocean wave energy as a source of renewable energy. By addressing the problem of designing efficient power electronics system to deliver 5 KW from the induction generator to the grid with less possible losses and harmonics as possible and to control current fed to the grid to successfully harvest ocean wave energy. We design an AC-DC full bridge rectifier converter, and a DC-DC boost converter to harvest wave energy from AC to regulated DC. In order to increase the design efficiency, we need to increase the power factor from (0.5-0.6) to 1. This is accomplished by designing the boost converter with power factor correction in continues mode with RC circuit as an input to the boost converter power factor correction. This design results in a phase shift between the input current and voltage of the full bridge rectifier to generate a small reactive power. The reactive power is injected to the induction generator to maintain its functionality by generating a magnetic field in its stator. Next, we design a single-phase pulse width modulator full bridge voltage source DC-AC grid-tied mode inverter to harvest regulated DC wave energy to AC. The designed inverter is modulated by inner current loop, to control current injected to the grid with minimal filter component to maintain power quality at the grid. The simulation results show that our design successfully control the current level fed to the grid. It is noteworthy that the simulated efficiency is higher than the calculated one since we used an ideal switch in the simulated circuit.

  7. Wind, Wave, and Tidal Energy Without Power Conditioning

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.

    2013-01-01

    Most present wind, wave, and tidal energy systems require expensive power conditioning systems that reduce overall efficiency. This new design eliminates power conditioning all, or nearly all, of the time. Wind, wave, and tidal energy systems can transmit their energy to pumps that send high-pressure fluid to a central power production area. The central power production area can consist of a series of hydraulic generators. The hydraulic generators can be variable displacement generators such that the RPM, and thus the voltage, remains constant, eliminating the need for further power conditioning. A series of wind blades is attached to a series of radial piston pumps, which pump fluid to a series of axial piston motors attached to generators. As the wind is reduced, the amount of energy is reduced, and the number of active hydraulic generators can be reduced to maintain a nearly constant RPM. If the axial piston motors have variable displacement, an exact RPM can be maintained for all, or nearly all, wind speeds. Analyses have been performed that show over 20% performance improvements with this technique over conventional wind turbines

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

    E-print Network

    Paris-Sud XI, Université de

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

  9. Power output variations of co-located offshore wind turbines and wave energy converters in California

    Microsoft Academic Search

    Eric D. Stoutenburg; Nicholas Jenkins; Mark Z. Jacobson

    2010-01-01

    The electric power generation of co-located offshore wind turbines and wave energy converters along the California coast is investigated. Meteorological wind and wave data from the National Buoy Data Center were used to estimate the hourly power output from offshore wind turbines and wave energy converters at the sites of the buoys. The data set from 12 buoys consists of

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

    E-print Network

    Brest, Université de

    A Predictive power control of Doubly Fed Induction Generator for Wave Energy Converter in Irregular Waves M.S. Lagoun 1 , A.Benalia1 1 Laboratoire d'Analyse et de Commande des Systèmes d'Energie et there are several wave energy converters to harness this energy. Some of them, as in tidal applications, use

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

    E-print Network

    Bailey, Helen Louise

    2011-11-22

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

  12. Power from Ocean Waves.

    ERIC Educational Resources Information Center

    Newman, J. N.

    1979-01-01

    Discussed is the utilization of surface ocean waves as a potential source of power. Simple and large-scale wave power devices and conversion systems are described. Alternative utilizations, environmental impacts, and future prospects of this alternative energy source are detailed. (BT)

  13. Grid connection of multi-Megawatt clean Wave energy power plant under weak grid condition

    Microsoft Academic Search

    Kai Rothenhagen; Marek Jasinski; Marian P. Kazmierkowski

    2008-01-01

    The WaveDragon is a 7 megawatt wave energy converter, that is currently developed for clean offshore energy production. The system will be floating several kilometres off the Pembrokeshire coast, Wales, UK, and transfers energy using a submarine power cable. Key interest is the control of the power take-off system at disturbed voltages and under weak-grid condition due to long submarine

  14. The Wave Power Group

    NSDL National Science Digital Library

    The Wave Power Group at the University of Edinburgh has produced a site primarily depicting its research into alternative power sources. Visitors will find a short history of the group, formed in 1974 after Steven Slater invented equipment to convert ocean wave energy into electricity. This is followed by descriptions of the group's recent efforts to develop similar technologies, including the curved wave tank and the 3D wave tank. The site is not limited to projects dealing with energy, however. It also discusses the potential development of a rain making machine and an instrument to detonate land minds without direct human involvement. Finally, visitors can view clips from the Power of Change video, which illustrate the works of the group. Engineers and students interested in alternative power research and other unique answers to global challenges will find this site extremely valuable.

  15. Optimal control of wave energy devices with various power-take-off mechanisms

    SciTech Connect

    Nichols, N.K.; Crossley, A. [Univ. of Reading, Whiteknights (United Kingdom). Dept. of Mathematics

    1996-12-31

    The aims of this research are to develop and test methods for analyzing and computing optimal control strategies for maximizing the useful power generated from wave energy converters incorporating realistic power-take-off and control mechanisms. Previously, strategies for maximizing energy absorbed by wave devices have been investigated, but these studies have assumed an ideal conversion rate using perfectly efficient turbomachinery with no constraints imposed by the generator capacity. In this paper various turbine characteristics and control mechanisms incorporating nonlinear losses are modelled, the qualitative properties of the optimal control strategy for maximizing average power delivered at the turbine shaft are analyzed, computational techniques for determining numerical solutions to the optimal control problem are established and the results are tested on a fully developed hydrodynamic model of a wave energy device.

  16. Design, simulation, and testing of a novel hydraulic power take-off system for the Pelamis wave energy converter

    Microsoft Academic Search

    Ross Henderson

    2006-01-01

    The economic viability of a wave energy converter depends largely on its power take-off system. Active control of the power take-off is necessary to maximise power capture across a range of sea-states and can also improve survivability. The high force, low speed regime of wave energy conversion makes it a suitable application for high-pressure hydraulics.This paper describes the hydraulic power

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

    SciTech Connect

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

    2012-04-01

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

  18. Power absorption by arrays of interacting vertical axisymmetric wave-energy devices

    SciTech Connect

    Mavrakos, S.A.; Kalofonos, A. [National Technical Univ. of Athens (Greece). Dept. of Naval Architecture and Marine Engineering

    1996-12-31

    The paper deals with the evaluation of the optimum wave-power absorption characteristics of arrays of interacting wave-energy devices. The hydrodynamic interference effects among the devices are exactly accounted for using a method that can solve the problem to any desired accuracy. The method is based on single body hydrodynamic characteristics that are properly combined through the physical idea of multiple scattering to account for interaction effects. Extensive numerical results for a variety of different array arrangements and individual device geometries are presented and comparisons are made to predictions based on approximate theories, the accuracy of which is critically assessed.

  19. 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 exceed this initial performance estimates. In advancing the Technology Readiness Level (TRL) of this type of wave energy converter from 3 to 4, we find the CycWEC to exceed our initial estimates in terms of hydrodynamic performance. Once fully developed and optimized, it has the potential to not just outperform all other WEC technologies, but to also deliver power at a lower LCOE than competing conventional renewables like wind and solar. Given the large wave power resource both domestically and internationally, this technology has the potential to lead to a large improvement in our ability to produce clean electricity at affordable cost.

  20. Performance Assessment of the Wave Dragon Wave Energy Converter

    E-print Network

    Hansen, René Rydhof

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

  1. Wave Power Demonstration Project at Reedsport, Oregon

    SciTech Connect

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

    2013-10-21

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

  2. Solar and wave powered AUV concept

    Microsoft Academic Search

    M. D. Ageev

    2000-01-01

    Performances of solar powered AUV, evidently, depend on available solar energy. Low efficiency of industrially produced solar panels (10-16%) affords sufficient amount of energy at low latitudes and does not at high latitudes of about 50 degrees and more. On the contrary, available wave energy distribution increases with latitude. A similar relation of solar and wave energies applies to their

  3. Electromagnetic wave energy converter

    NASA Technical Reports Server (NTRS)

    Bailey, R. L. (inventor)

    1973-01-01

    Electromagnetic wave energy is converted into electric power with an array of mutually insulated electromagnetic wave absorber elements each responsive to an electric field component of the wave as it impinges thereon. Each element includes a portion tapered in the direction of wave propagation to provide a relatively wideband response spectrum. Each element includes an output for deriving a voltage replica of the electric field variations intercepted by it. Adjacent elements are positioned relative to each other so that an electric field subsists between adjacent elements in response to the impinging wave. The electric field results in a voltage difference between adjacent elements that is fed to a rectifier to derive dc output power.

  4. Negative energy waves

    NASA Astrophysics Data System (ADS)

    Lashmore-Davies, C. N.

    2005-04-01

    A brief history of the concept of negative energy waves in fluid and plasma media is given. The theory of microwave tubes is highlighted, where the small signal power theorem was first derived, which led to the interpretation of these devices in terms of the interaction of positive and negative energy waves. Three examples are described to illustrate the use of negative waves in stability problems. The first is concerned with the Kelvin-Helmholtz instability in neutral fluids. The second comes from a kinetic theory of instability in a collisionless shock wave in a magnetized plasma, and the third is concerned with the effect of a resistive wall and plasma flow on the magnetohydrodynamic stability of a magnetically confined plasma. The paper ends with some general conclusions.

  5. Prototype testing of the wave energy converter wave dragon

    Microsoft Academic Search

    Jens Peter Kofoed; Peter Frigaard; Erik Friis-Madsen; Hans Chr. Sørensen

    2006-01-01

    The Wave Dragon is an offshore wave energy converter of the overtopping type. It consists of two wave reflectors focusing the incoming waves towards a ramp, a reservoir for collecting the overtopping water and a number of hydro turbines for converting the pressure head into power.In the period from 1998 to 2001 extensive wave tank testing on a scale model

  6. Improved power capacity in a high efficiency klystron-like relativistic backward wave oscillator by distributed energy extraction

    NASA Astrophysics Data System (ADS)

    Xiao, Renzhen; Chen, Changhua; Cao, Yibing; Sun, Jun

    2013-12-01

    With the efficiency increase of a klystron-like relativistic backward wave oscillator, the maximum axial electric field and harmonic current simultaneously appear at the end of the beam-wave interaction region, leading to a highly centralized energy exchange in the dual-cavity extractor and a very high electric field on the cavity surface. Thus, we present a method of distributed energy extraction in this kind of devices. Particle-in-cell simulations show that with the microwave power of 5.1 GW and efficiency of 70%, the maximum axial electric field is decreased from 2.26 MV/cm to 1.28 MV/cm, indicating a threefold increase in the power capacity.

  7. Improved power capacity in a high efficiency klystron-like relativistic backward wave oscillator by distributed energy extraction

    SciTech Connect

    Xiao, Renzhen; Chen, Changhua; Cao, Yibing; Sun, Jun [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an 710024 (China)

    2013-12-07

    With the efficiency increase of a klystron-like relativistic backward wave oscillator, the maximum axial electric field and harmonic current simultaneously appear at the end of the beam-wave interaction region, leading to a highly centralized energy exchange in the dual-cavity extractor and a very high electric field on the cavity surface. Thus, we present a method of distributed energy extraction in this kind of devices. Particle-in-cell simulations show that with the microwave power of 5.1?GW and efficiency of 70%, the maximum axial electric field is decreased from 2.26 MV/cm to 1.28 MV/cm, indicating a threefold increase in the power capacity.

  8. Design of a hydraulic power take-off system for the wave energy device with an inverse pendulum

    NASA Astrophysics Data System (ADS)

    Zhang, Da-hai; Li, Wei; Zhao, Hai-tao; Bao, Jing-wei; Lin, Yong-gang

    2014-04-01

    This paper describes a dual-stroke acting hydraulic power take-off (PTO) system employed in the wave energy converter (WEC) with an inverse pendulum. The hydraulic PTO converts slow irregular reciprocating wave motions to relatively smooth, fast rotation of an electrical generator. The design of the hydraulic PTO system and its control are critical to maximize the generated power. A time domain simulation study and the laboratory experiment of the full-scale beach test are presented. The results of the simulation and laboratory experiments including their comparison at full-scale are also presented, which have validated the rationality of the design and the reliability of some key components of the prototype of the WEC with an inverse pendulum with the dual-stroke acting hydraulic PTO system.

  9. Experimental Studies of Wave Hydraulic Power Units

    Microsoft Academic Search

    V. P. Drobakhin; N. D. Nolirovskaya; V. A. Osadchuk; A. V. Savchenko

    2003-01-01

    At the Ukrgidroproekt Joint-Stock Co. (Kharkov), research and development studies concerned with the use of wave energy have been conducted over a period of years. Under a Reseacrh and Developement program in 1994 – 1995, a model of a wave power plant was tested at a laboratory for large-scale hydraulic and geotechnic studies (LHGSL, Dneprodzerzhinsk) and promising results were obtained

  10. Alfvénic waves with sufficient energy to power the quiet solar corona and fast solar wind.

    PubMed

    McIntosh, Scott W; De Pontieu, Bart; Carlsson, Mats; Hansteen, Viggo; Boerner, Paul; Goossens, Marcel

    2011-07-28

    Energy is required to heat the outer solar atmosphere to millions of degrees (refs 1, 2) and to accelerate the solar wind to hundreds of kilometres per second (refs 2-6). Alfvén waves (travelling oscillations of ions and magnetic field) have been invoked as a possible mechanism to transport magneto-convective energy upwards along the Sun's magnetic field lines into the corona. Previous observations of Alfvénic waves in the corona revealed amplitudes far too small (0.5?km?s(-1)) to supply the energy flux (100-200?W?m(-2)) required to drive the fast solar wind or balance the radiative losses of the quiet corona. Here we report observations of the transition region (between the chromosphere and the corona) and of the corona that reveal how Alfvénic motions permeate the dynamic and finely structured outer solar atmosphere. The ubiquitous outward-propagating Alfvénic motions observed have amplitudes of the order of 20?km?s(-1) and periods of the order of 100-500?s throughout the quiescent atmosphere (compatible with recent investigations), and are energetic enough to accelerate the fast solar wind and heat the quiet corona. PMID:21796206

  11. Proposed electromagnetic wave energy converter

    NASA Technical Reports Server (NTRS)

    Bailey, R. L.

    1973-01-01

    Device converts wave energy into electric power through array of insulated absorber elements responsive to field of impinging electromagnetic radiation. Device could also serve as solar energy converter that is potentially less expensive and fragile than solar cells, yet substantially more efficient.

  12. Wave power absorption: Experiments in open sea and simulation

    Microsoft Academic Search

    M. Eriksson; R. Waters; O. Svensson; J. Isberg; M. Leijon

    2007-01-01

    A full scale prototype of a wave power plant based on a direct drive linear generator driven by a point absorber has been installed at the west coast of Sweden. In this paper, experimentally collected data of energy absorption for different electrical loads are used to verify a model of the wave power plant including the interactions of wave, buoy,

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

    E-print Network

    Li, Bin

    2012-11-29

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

  14. Wave Energy challenges and possibilities

    E-print Network

    © Wave Energy ­ challenges and possibilities By: Per Resen Steenstrup www.WaveStarEnergy.com Risø-R-1608(EN) 161 #12;© Wave energy is an old story.... The first wave energy patent is 200 years old. Over the last 100 years more than 200 new wave energy devices have been developped and more than 1.000 patents

  15. Research on energy conversion system of floating wave energy converter

    NASA Astrophysics Data System (ADS)

    Zhang, Ya-qun; Sheng, Song-wei; You, Ya-ge; Wu, Bi-jun; Liu, Yang

    2014-03-01

    A wave power device includes an energy harvesting system and a power take-off system. The power take-off system of a floating wave energy device is the key that converts wave energy into other forms. A set of hydraulic power take-off system, which suits for the floating wave energy devices, includes hydraulic system and power generation system. The hydraulic control system uses a special "self-hydraulic control system" to control hydraulic system to release or save energy under the maximum and the minimum pressures. The maximum pressure is enhanced to 23 MPa, the minimum to 9 MPa. Quite a few experiments show that the recent hydraulic system is evidently improved in efficiency and reliability than our previous one, that is expected to be great significant in the research and development of our prototype about wave energy conversion.

  16. Feasibility of Wave Energy in Hong Kong

    NASA Astrophysics Data System (ADS)

    Lu, M.; Hodgson, P.

    2014-12-01

    Kinetic energy produced by the movement of ocean waves can be harnessed by wave energy converter equipment such as wave turbines to power onshore electricity generators, creating a valuable source of renewable energy. This experiment measures the potential of wave energy in Hoi Ha Wan Marine Park, Hong Kong using a data buoy programmed to send data through wireless internet every five minutes. Wave power (known as 'wave energy flux') is proportional to wave energy periodicity and to the square of wave height, and can be calculated using the equation: P = 0.5 kW/(m3)(s) x Hs2 x Tp P = wave energy flux (wave energy per unit of wave crest length in kW/m) Hs = significant wave height (m) Tp = wave period (seconds) Acoustic Doppler Current Profilers (ADCPs), or ultrasonic sensors, were installed on the seabed at three monitoring locations to measure Significant Wave Heights (Hs), Significant Wave Periods (Tp) and Significant Wave Direction (Wd). Over a twelve month monitoring period, Significant Wave Heights ranged from 0 ~ 8.63m. Yearly averages were 1.051m. Significant Wave Period ranged from 0 ~ 14.9s. Yearly averages were 6.846s. The maximum wave energy amount recorded was 487.824 kW/m. These results implied that electricity sufficient to power a small marine research center could be supplied by a generator running at 30% efficiency or greater. A wave piston driven generator prototype was designed that could meet output objectives without using complex hydraulics, expensive mechanical linkages, or heavy floating buoys that might have an adverse impact on marine life. The result was a design comprising a water piston connected by an air pipe to a rotary turbine powered generator. A specially designed air valve allowed oscillating bidirectional airflow generated in the piston to be converted into unidirectional flow through the turbine, minimizing kinetic energy loss. A 35cm wave with a one second period could generate 139.430W of electricity, with an efficiency of 37.6%.

  17. Power recycling for an interferometric gravitational wave

    E-print Network

    Ejiri, Shinji

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

  18. High power broadband millimeter wave TWTs

    Microsoft Academic Search

    Bill G. James

    1999-01-01

    In the early 1980's the requirement for high power broadband millimeter wave sources encouraged the development of microwave vacuum device amplifiers for radar and communication systems. Many government funded programs were implemented for the development of high power broadband millimeter wave amplifiers that would meet the needs of the high power community. The tube design capable of meeting these goals

  19. High power broadband millimeter wave TWTs

    Microsoft Academic Search

    Bill G. James

    1999-01-01

    In the early 1980’s the requirement for high power broadband millimeter wave sources encouraged the development of microwave vacuum device amplifiers for radar and communication systems. Many government funded programs were implemented for the development of high power broadband millimeter wave amplifiers that would meet the needs of the high power community. The tube design capable of meeting these goals

  20. High Power Broadband Millimeter Wave TWTs

    Microsoft Academic Search

    Bill G. James

    1998-01-01

    In the early 1980's the requirement for high power broadband millimeter wave sources encouraged the development of microwave vacuum device amplifiers for radar and communication systems. Many government funded programs were implemented for the development of high power broadband millimeter wave amplifiers that would meet the needs of the high power community. The tube design capable of meeting these goals

  1. Modelling and geometry optimisation of wave energy converters

    E-print Network

    Nørvåg, Kjetil

    Modelling and geometry optimisation of wave energy converters Adi Kurniawan Supervisors: Prof DIY Riding radical wave power" #12;#12;Any device will deliver some energyAny device will deliver some energy #12;What matters is the cost of energy Ultimate problem Given the waves, design a device

  2. California Small Hydropower and Ocean Wave Energy

    E-print Network

    California Small Hydropower and Ocean Wave Energy Resources IN SUPPORT OF THE 2005 INTEGRATED....................................................................................................................... 9 Ocean Wave Energy............................................................................................................. 20 Wave Energy Conversion Technology

  3. Fundamental formulae for wave-energy conversion

    PubMed Central

    Falnes, Johannes; Kurniawan, Adi

    2015-01-01

    The time-average wave power that is absorbed from an incident wave by means of a wave-energy conversion (WEC) unit, or by an array of WEC units—i.e. oscillating immersed bodies and/or oscillating water columns (OWCs)—may be mathematically expressed in terms of the WEC units' complex oscillation amplitudes, or in terms of the generated outgoing (diffracted plus radiated) waves, or alternatively, in terms of the radiated waves alone. Following recent controversy, the corresponding three optional expressions are derived, compared and discussed in this paper. They all provide the correct time-average absorbed power. However, only the first-mentioned expression is applicable to quantify the instantaneous absorbed wave power and the associated reactive power. In this connection, new formulae are derived that relate the ‘added-mass’ matrix, as well as a couple of additional reactive radiation-parameter matrices, to the difference between kinetic energy and potential energy in the water surrounding the immersed oscillating WEC array. Further, a complex collective oscillation amplitude is introduced, which makes it possible to derive, by a very simple algebraic method, various simple expressions for the maximum time-average wave power that may be absorbed by the WEC array. The real-valued time-average absorbed power is illustrated as an axisymmetric paraboloid defined on the complex collective-amplitude plane. This is a simple illustration of the so-called ‘fundamental theorem for wave power’. Finally, the paper also presents a new derivation that extends a recently published result on the direction-average maximum absorbed wave power to cases where the WEC array's radiation damping matrix may be singular and where the WEC array may contain OWCs in addition to oscillating bodies.

  4. The Wave Glider: A Wave-Powered autonomous marine vehicle

    Microsoft Academic Search

    R. Hine; S. Willcox; G. Hine; T. Richardson

    2009-01-01

    The wave glider is a new autonomous marine vehicle that is unique in its ability to harness ocean wave energy for platform propulsion. This paper provides an overview of the wave glider vehicle's architecture and capabilities, and presents results from the extensive engineering sea trials that we have conducted with several prototype and the current production generations of the vehicle.

  5. Enhanced Singular Wave Reactor for Surface Power

    NASA Astrophysics Data System (ADS)

    Popa-Simil, L.

    The "CANDLE" (Constant Axial shape of Neutron flux, nuclide densities and power shape During Life of Energy producing reactor) also known as singular wave reactor has many significant advantages related to elimination of the need for enrichment. The use of micro-hetero structured fuel, generically called "cer-liq-mesh" will further improve burnup up to 90%. In spite it has typically large dimensions, being heavy to be transported in space, in a single piece, but because it will deliver energy in hundreds MW level for about 100 years per charge using natural Uranium or Thorium as fuel available on the planet's surface, and because it can be assembled locally becomes a very attractive option for self sustainable power cycles. The "cer-liq-mesh" fuel based singular wave reactor is smaller, less than ¼ from the size of "Candle" reactor, and has a very high burnup reducing the fuel cycle drastically. It can be transported by parts, with extremely small probability of over-unity criticality accident and be assembled to run on the surface. This represents a better option for extraterrestrial applications; in spite it requires a more complicated fuel fabrication that pays back in a simplified fuel cycle and minimum waste.

  6. Compact autonomous explosive-driven pulsed power system based on a capacitive energy storage charged by a high-voltage shock-wave ferromagnetic generator

    NASA Astrophysics Data System (ADS)

    Shkuratov, Sergey I.; Talantsev, Evgueni F.; Baird, Jason; Altgilbers, Larry L.; Stults, Allen H.

    2006-06-01

    A new concept for constructing compact autonomous pulsed power systems is presented. This concept utilizes a high-voltage explosive-driven shock-wave ferromagnetic generator (FMG) as a charging source for capacitive energy storage. It has been experimentally demonstrated that miniature FMGs (22-25cm3 in size and 84-95g in mass) developed for these experiments can be successfully used to charge capacitor banks. The FMGs, containing Nd2Fe14B energy-carrying elements, provided pulsed powers of 35-45kW in times ranging from 10to15?s. A methodology was developed for digital simulation of the operation of the transverse FMG. Experimental results that were obtained are in a good agreement with the results of digital simulations.

  7. OPTIMUM CONTROL OF OSCILLATION OF WAVE-ENERGY CONVERTERS

    Microsoft Academic Search

    J. Falnes

    1993-01-01

    The power output from wave energy converters (WECs) may be increased by controlling the oscillation in order to approach an optimum interaction between the WEC and the incident wave. Optimally controlled WECs, designed to operate at full capacity a rather large fraction of their lifetime, may improve the economic prospects for wave power significantly. Most of the WECs discussed here,

  8. HARNESSING OCEAN WAVE ENERGY TO GENERATE ELECTRICITY

    EPA Science Inventory

    A technical challenge to sustainability is finding an energy source that is abundant enough to meet global demands without producing greenhouse gases or radioactive waste. Energy from ocean surface waves can provide the people of this planet a clean, endless power source to me...

  9. High power millimeter wave source development program

    NASA Technical Reports Server (NTRS)

    George, T. V.

    1989-01-01

    High power millimeter wave sources for fusion program; ECH source development program strategy; and 1 MW, 140 GHz gyrotron experiment design philosophy are briefly outlined. This presentation is represented by viewgraphs only.

  10. Dissipation of Rayleigh Wave Energy

    Microsoft Academic Search

    Eysteinn Tryggavson

    1965-01-01

    Records of long-period vertical seismographs from 14 stations in the standard- ized world-wide seismograph network were used to determine the energy dissipation of Rayleigh waves. Records of Rayleigh waves produced by the nuclear explosion of September 19, 1962, near Novaya Zcmlya, were digitized and Fourier analyzed, and the dissipation was computed for waves of periods between 10 and 100 seconds.

  11. Power conditioning system for energy sources

    DOEpatents

    Mazumder, Sudip K. (Chicago, IL); Burra, Rajni K. (Chicago, IL); Acharya, Kaustuva (Chicago, IL)

    2008-05-13

    Apparatus for conditioning power generated by an energy source includes an inverter for converting a DC input voltage from the energy source to a square wave AC output voltage, and a converter for converting the AC output voltage from the inverter to a sine wave AC output voltage.

  12. Wave energy and intertidal productivity

    Microsoft Academic Search

    E. G. Jr. Leigh; R. T. Paine; J. F. Quinn; T. H. Suchanek

    1987-01-01

    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 >

  13. A review of wave-energy extraction

    Microsoft Academic Search

    Johannes Falnes

    2007-01-01

    Comparing ocean-wave energy with its origin, wind energy, the former is more persistent and spatially concentrated. In this paper wave spectrum parameters related to transport, distribution and variability of wave energy in the sea are educed. Many different types of wave-energy converters, of various categories, have been proposed. It is useful to think of primary conversion of wave energy by

  14. Climate change impact on wave energy in the Persian Gulf

    NASA Astrophysics Data System (ADS)

    Kamranzad, Bahareh; Etemad-Shahidi, Amir; Chegini, Vahid; Yeganeh-Bakhtiary, Abbas

    2015-06-01

    Excessive usage of fossil fuels and high emission of greenhouse gases have increased the earth's temperature, and consequently have changed the patterns of natural phenomena such as wind speed, wave height, etc. Renewable energy resources are ideal alternatives to reduce the negative effects of increasing greenhouse gases emission and climate change. However, these energy sources are also sensitive to changing climate. In this study, the effect of climate change on wave energy in the Persian Gulf is investigated. For this purpose, future wind data obtained from CGCM3.1 model were downscaled using a hybrid approach and modification factors were computed based on local wind data (ECMWF) and applied to control and future CGCM3.1 wind data. Downscaled wind data was used to generate the wave characteristics in the future based on A2, B1, and A1B scenarios, while ECMWF wind field was used to generate the wave characteristics in the control period. The results of these two 30-yearly wave modelings using SWAN model showed that the average wave power changes slightly in the future. Assessment of wave power spatial distribution showed that the reduction of the average wave power is more in the middle parts of the Persian Gulf. Investigation of wave power distribution in two coastal stations (Boushehr and Assalouyeh ports) indicated that the annual wave energy will decrease in both stations while the wave power distribution for different intervals of significant wave height and peak period will also change in Assalouyeh according to all scenarios.

  15. Author's personal copy Wave energy resources along the Hawaiian Island chain

    E-print Network

    Author's personal copy Wave energy resources along the Hawaiian Island chain Justin E. Stopa model Wave atlas Wave energy Wave power a b s t r a c t Hawaii's access to the ocean and remoteness from demand for sustainable energy. The wave resources include swells from distant storms and year-round seas

  16. Multiphysics simulation of wave energy to electric energy conversion by permanent magnet linear generator

    Microsoft Academic Search

    Mats Leijon; Hans Bernhoff; Olov Ågren; Jan Isberg; Jan Sundberg; Marcus Berg; Karl Erik Karlsson; Arne Wolfbrandt

    2005-01-01

    The possibility to use three-phase permanent magnet linear generators to convert sea wave energy into electric energy is investigated by multiphysics simulations. The results show a possibility, which needs to be further verified by experimental tests, for a future step toward a sustainable electric power production from ocean waves by using direct conversion. The results suggest that wave energy can

  17. Protective, Modular Wave Power Generation System

    SciTech Connect

    Vvedensky, Jane M.; Park, Robert Y.

    2012-11-27

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

  18. Guidelines in Wave Energy Conversion System Design 

    E-print Network

    Guiberteau, K. L.; Liu, Y.; Lee, J.; Kozman, T.

    2014-01-01

    student for the Industrial Assessment Center at the University of Louisiana at Lafayette, and her research interests include energy management, integrated product and process design, and wave energy. Email: kguiberteau@gmail.com Theodore A. Kozman... uses large arrays to provide for higher demands [13]. According to the Ocean Power Technology website (www.oceanpowertechnologies.com), the company is planning on building a commercial unit off the coast of Spain, which will generate 1.39 MW...

  19. A review of impulse turbines for wave energy conversion

    Microsoft Academic Search

    T Setoguchi; S Santhakumar; H Maeda; M Takao; K Kaneko

    2001-01-01

    Oscillating Water Column based wave energy plants convert wave energy into low pressure pnuematic power in the form of bi-directional air flows. Air turbines which are capable of rotating uni-directionally in bi-directional air flow, otherwise also known as self-rectifying turbines, are used to extract mechanical shaft power which is further converted into electrical power by a generator. This paper reviews

  20. Float pump offshore wave energy converters

    SciTech Connect

    Nielsen, K. [Danish Wave Power Aps, Virum (Denmark)

    1996-12-31

    This paper will describe the numerical design models developed by DWP and ES-Consult as part of the Off-shore Wave Energy Converter project OWEC-1 supported by the European Union under the JOULE initiative. Offshore Wave Power Plants composed of float pump systems, has been investigated. Modeling techniques required to provide reliable methods for the predicted hydrodynamic behavior of the floats, their performance has been assessed and standardized criteria and techniques for the design has been provided. The systems investigated and the numerical time domain models developed will be described. The DWP/ES-Consult design models include both heave and surge motion of the device motion. The hydrodynamics are based on the long wave approximation of wave exiting forces as well as nonlinear drag and lift-forces, limits for the buoyancy force and variation of added mass with submergence are included in the calculations. The numerical models developed by DWP/ES-Consult are intended as tools for the structural design. The results in medium waves are compared to more exact hydrodynamic models (heave only) developed at Chalmars University and at NTH norwegian Technical University. Results are compared to model tests and real sea measurements. The design of the float geometry`s and power takeoff has not been optimized. The scope has been to compare and provide tools and guidelines for time domain modeling of offshore wave energy converters as a basis for further optimization.

  1. IEEE Power and Energy

    NSDL National Science Digital Library

    2003-01-01

    IIEEE presents Power and Energy magazine online. The latest issue as well as several previous issues are available online for free use. Columns of Power and Energy highlight history, industry news, standards, and opinion articles. The archives currently go back to 2009.

  2. Wave Energy Extraction from buoys

    E-print Network

    Garnaud, Xavier

    2009-01-01

    Different types of Wave Energy Converters currently tested or under development are using the vertical movement of floating bodies to generate electricity. For commercial applications, arrays have to be considered in order ...

  3. Tunnel effect wave energy detection

    NASA Technical Reports Server (NTRS)

    Kaiser, William J. (Inventor); Waltman, Steven B. (Inventor); Kenny, Thomas W. (Inventor)

    1995-01-01

    Methods and apparatus for measuring gravitational and inertial forces, magnetic fields, or wave or radiant energy acting on an object or fluid in space provide an electric tunneling current through a gap between an electrode and that object or fluid in space and vary that gap with any selected one of such forces, magnetic fields, or wave or radiant energy acting on that object or fluid. These methods and apparatus sense a corresponding variation in an electric property of that gap and determine the latter force, magnetic fields, or wave or radiant energy in response to that corresponding variation, and thereby sense or measure such parameters as acceleration, position, particle mass, velocity, magnetic field strength, presence or direction, or wave or radiant energy intensity, presence or direction.

  4. Arnold Schwarzenegger DEVELOPING WAVE ENERGY IN

    E-print Network

    Arnold Schwarzenegger Governor DEVELOPING WAVE ENERGY IN COASTAL CALIFORNIA: POTENTIAL SOCIO. Developing Wave Energy In Coastal California: Potential Socio-Economic And Environmental Effects. California-ECONOMIC AND ENVIRONMENTAL EFFECTS Prepared For: California Energy Commission Public Interest Energy Research Program

  5. Nonlinear Analysis of Wave Energy Dissipation and Energy Transfer of Directional Breaking Waves in Deep Water

    Microsoft Academic Search

    Keyyong Hong; Shuxue Liu; E. Meza; Jun Zhang

    2006-01-01

    Wave energy dissipation and energy transfer among wave components during the directional wave breaking are investigated experimentally. Directional breaking waves in deep water were simulated by focusing the multi-frequency and multi-directional wave components at a designed location based on constant wave amplitude and constant wave steepness frequency spectrum. The incipient and plunging breakers with the same spectral characteristics were generated

  6. Experimental results from wave tank trials of a multi-axis wave energy converter

    NASA Astrophysics Data System (ADS)

    Zhang, Dahai; Aggidis, George; Wang, Yifei; Mccabe, Andy; Li, Wei

    2013-09-01

    A 1/64th scale prototype of multi-axis wave energy converter (WEC) has been tested in the wave tank and the overall concept has been verified. It is shown that when multiple directions of motion are involved, the multi-axis WEC proves to be able to supply more power generation than a single axis one. Results demonstrated that the optimal resonant frequency for maximum power output under different damping values does not vary with wave climate. It is also shown that large overload capability of the system is critical, and indicated that, electric power system is essential to reduce power fluctuations.

  7. The Dynamics of Wave Energy

    Microsoft Academic Search

    John Ringwood

    This paper examines the challenges of ecien tly har- nessing wave energy. A variety of energy conversion device types is reviewed and a generic heaving buoy device selected for detailed examination. A number of modelling and control challenges are de- tailed and a hierarchical control structure is indicated. Both potable water production and electricity generation are included as possible uses

  8. Direct Drive Wave Energy Buoy

    SciTech Connect

    Rhinefrank, Kenneth E. [Columbia Power Technologies, Inc.; Lenee-Bluhm, Pukha [Columbia Power Technologies, Inc.; Prudell, Joseph H. [Columbia Power Technologies, Inc.; Schacher, Alphonse A. [Columbia Power Technologies, Inc.; Hammagren, Erik J. [Columbia Power Technologies, Inc.; Zhang, Zhe [Columbia Power Technologies, Inc.

    2013-07-29

    The most prudent path to a full-scale design, build and deployment of a wave energy conversion (WEC) system involves establishment of validated numerical models using physical experiments in a methodical scaling program. This Project provides essential additional rounds of wave tank testing at 1:33 scale and ocean/bay testing at a 1:7 scale, necessary to validate numerical modeling that is essential to a utility-scale WEC design and associated certification.

  9. Wave energy transformation on natural profiles

    Microsoft Academic Search

    T. C. Lippmann; A. H. Brookins; E. B. Thornton

    1996-01-01

    A wave energy transformation model, which includes wave breaking within the surf zone described by surface rollers, is developed for randomly varying waves over arbitrary bathymetry. The model includes roller energy gradients in the energy flux balance, and further specifies the dissipation function based on roller theory following Svendsen. Root-mean-square wave heights, Hrms, are found across the surf zone by

  10. Group velocity and power flow relations for surface waves in plane-stratified anisotropic media

    Microsoft Academic Search

    H. Bertoni; A. Hessel

    1966-01-01

    Two aspects of power flow associated with electromagnetic waves in plane-stratified, dispersive, anisotropic media that are also lossless and linear are considered. One aspect is the relation between group velocity and the velocity of energy transport of surface waves in such media. It is shown that the group velocity of surface waves is equal to the ratio of the real

  11. Assessing wave energy effects on biodiversity: the wave hub experience.

    PubMed

    Witt, M J; Sheehan, E V; Bearhop, S; Broderick, A C; Conley, D C; Cotterell, S P; Crow, E; Grecian, W J; Halsband, C; Hodgson, D J; Hosegood, P; Inger, R; Miller, P I; Sims, D W; Thompson, R C; Vanstaen, K; Votier, S C; Attrill, M J; Godley, B J

    2012-01-28

    Marine renewable energy installations harnessing energy from wind, wave and tidal resources are likely to become a large part of the future energy mix worldwide. The potential to gather energy from waves has recently seen increasing interest, with pilot developments in several nations. Although technology to harness wave energy lags behind that of wind and tidal generation, it has the potential to contribute significantly to energy production. As wave energy technology matures and becomes more widespread, it is likely to result in further transformation of our coastal seas. Such changes are accompanied by uncertainty regarding their impacts on biodiversity. To date, impacts have not been assessed, as wave energy converters have yet to be fully developed. Therefore, there is a pressing need to build a framework of understanding regarding the potential impacts of these technologies, underpinned by methodologies that are transferable and scalable across sites to facilitate formal meta-analysis. We first review the potential positive and negative effects of wave energy generation, and then, with specific reference to our work at the Wave Hub (a wave energy test site in southwest England, UK), we set out the methodological approaches needed to assess possible effects of wave energy on biodiversity. We highlight the need for national and international research clusters to accelerate the implementation of wave energy, within a coherent understanding of potential effects-both positive and negative. PMID:22184674

  12. Quantification of the influence of directional sea state parameters over the performances of wave energy converters 

    E-print Network

    Pascal, Remy Claude Rene

    2012-11-29

    Accurate predictions of the annual energy yield from wave energy converters are essential to the development of the wave industry. The current method based on power matrices uses only a small part of the data available ...

  13. Electron Acceleration by High Power Radio Waves in the Ionosphere

    NASA Astrophysics Data System (ADS)

    Bernhardt, Paul

    2012-10-01

    At the highest ERP of the High Altitude Auroral Research Program (HAARP) facility in Alaska, high frequency (HF) electromagnetic (EM) waves in the ionosphere produce artificial aurora and electron-ion plasma layers. Using HAARP, electrons are accelerated by high power electrostatic (ES) waves to energies >100 times the thermal temperature of the ambient plasma. These ES waves are driven by decay of the pump EM wave tuned to plasma resonances. The most efficient acceleration process occurs near the harmonics of the electron cyclotron frequency in earth's magnetic field. Mode conversion plays a role in transforming the ES waves into EM signals that are recorded with ground receivers. These diagnostic waves, called stimulated EM emissions (SEE), show unique resonant signatures of the strongest electron acceleration. This SEE also provides clues about the ES waves responsible for electron acceleration. The electron gas is accelerated by high frequency modes including Langmuir (electron plasma), upper hybrid, and electron Bernstein waves. All of these waves have been identified in the scattered EM spectra as downshifted sidebands of the EM pump frequency. Parametric decay is responsible low frequency companion modes such as ion acoustic, lower hybrid, and ion Bernstein waves. The temporal evolution of the scattered EM spectrum indicates development of field aligned irregularities that aid the mode conversion process. The onset of certain spectral features is strongly correlated with glow plasma discharge structures that are both visible with the unaided eye and detectable using radio backscatter techniques at HF and UHF frequencies. The primary goals are to understand natural plasma layers, to study basic plasma physics in a unique ``laboratory with walls,'' and to create artificial plasma structures that can aid radio communications.

  14. CHARACTERIZING DANGEROUS WAVES FOR OCEAN WAVE ENERGY CONVERTER SURVIVABILITY Justin Hovland

    E-print Network

    Haller, Merrick

    CHARACTERIZING DANGEROUS WAVES FOR OCEAN WAVE ENERGY CONVERTER SURVIVABILITY Justin Hovland ABSTRACT Ocean Wave Energy Converters (OWECs) operating on the water surface are subject to storms at station 139. Keywords: wave energy, survivability, breaking waves, joint distribution, OWEC INTRODUCTION

  15. Seminario de Matemtica Aplicada "Renowable wave energy

    E-print Network

    Tradacete, Pedro

    Seminario de Matemática Aplicada "Renowable wave energy: potencial and technical challenges Abstract: Among the various renewable energy sources, ocean wave energy has been only recently investiga will be at first to introduce the potential of wave energy, as a significant, and often neglected, contributor

  16. Wave energy transmission system concepts for linear generator arrays

    Microsoft Academic Search

    Karin Thorburn; Hans Bernhoff; Mats Leijon

    2004-01-01

    Wave energy is a renewable source, which has so far not been exploited widely. Many of the various schemes in the past consist of large mechanical structures, often located near the sea surface. This article presents a range of systems with point absorbers on the surface and linear generators placed on the seabed, converting the wave motion into electrical power.

  17. Ocean wave energy converting vessel

    SciTech Connect

    Boyce, P.F.

    1986-08-26

    An ocean wave energy conversion system is described comprised of a four beam quadrapod supported by bouyant members from which is suspended a pendulum. The pendulum contains a vertical generator shaft and a generator, the generator shaft being splined and fitted with two racheted pulleys, the pulleys being looped, one clockwise and one counterclockwise with separate cables. The cables are attached at their ends to the bow and stern of the quadrapod, whereby the generator shaft will pin when the quadrapod rocks over waves and the pendulum tends toward the center of earth.

  18. Quasi-optical millimeter wave power combining

    NASA Astrophysics Data System (ADS)

    Summers, C. J.; Wiltse, J. C.; Harris, H. M.; McMillan, R. W.; Torabi, A.

    1995-02-01

    The research described in this report was based on concepts advanced earlier by Dr. James W. Mink, then of the Army Research Office. His analyses for quasi-optical power combining from solid-state source arrays have formed a strong basis for a number of investigations in this field in recent years. Previous studies dealt with microwave arrays, while the present one was the first to deal with millimeter-wave arrays of FET's and HEMT's. Dr. Mink served as the A.R.O. technical monitor for the majority of this project, and the authors would like to express appreciation for his advice and contributions.

  19. Wave Energy Budget in the Earth Radiation Belts

    NASA Astrophysics Data System (ADS)

    Artemyev, Anton; Agapitov, Oleksiy; Mourenas, Didier; Krasnoselskikh, Vladimir; Mozer, Forest

    2015-04-01

    Whistlers are important electromagnetic waves pervasive in Earth's magnetosphere, where they continuously remove or energize electrons trapped by the geomagnetic field, controlling radiation hazards to satellites and astronauts and ionization or chemical composition in the upper-atmosphere. Here, we report an analysis of ten-year Cluster data, evaluating for the first time the wave energy budget in Earth's magnetosphere and revealing that a significant fraction of the energy corresponds to hitherto generally neglected very oblique waves. Such waves, with ten times smaller magnetic power than parallel waves, typically have similar total energy. Very oblique waves may turn out to be a crucial agent of energy redistribution in Earth's radiation belts, controlled by solar activity.

  20. Wave and tide powered generation apparatus

    SciTech Connect

    Suggs, L. F.

    1985-09-03

    A wave and tide powered generation apparatus includes a frame which is fixed relative to the varying level of the body of water, and includes a float operably associated with the frame for movement in response to the varying level of the body of water. A rotatable drum is attached to the float and has a drive line with a middle portion wrapped around the rotatable drum. Upper and lower ends of the drive line are attached to upper and lower portions of the frame. Movement of the float upward or downward relative to the frame causes the rotatable drum to be rotated due to its engagement with the drive line. A power transfer apparatus transmits the rotary motion of the drum to a generator.

  1. Track 2: Sustainable Energy I. Renewable Energy: Wind and Wave

    E-print Network

    1 Track 2: Sustainable Energy I. Renewable Energy: Wind and Wave II. Renewable Energy: Solar III. Biomass: Waste to Fuel IV. Biomass Energy Recovery Optimization 1. Renewable Energy Wind & Wave: Speakers, operates in shallow water, has no visual impact, and does not threaten wildlife.!!!! Wave Energy Proving

  2. Solar flares and focused energy transport by MHD waves

    NASA Astrophysics Data System (ADS)

    Russell, A. J. B.; Stackhouse, D. J.

    2013-10-01

    Context. Transport of flare energy from the corona to the chromosphere has traditionally been assigned to electron beams; however, interest has recently been renewed in magnetohydrodynamic (MHD) waves as a complementary or alternative mechanism. Aims: We determine whether, and under what conditions, MHD waves deliver spatially localised energy to the chromosphere, as required if MHD waves are to contribute to emission from flare ribbons and kernels. This paper also highlights several properties of MHD waves that are relevant to solar flares and demonstrates their application to the flare problem. Methods: Transport is investigated using a magnetic arcade model and 2.5D MHD simulations. Different wave polarisations are considered and the effect of fine structuring transverse to the magnetic field is also examined. Ray tracing provides additional insight into the evolution of waveguided fast waves. Results: Alfvén waves are very effective at delivering energy fluxes to small areas of chromosphere, localisation being enhanced by magnetic field convergence and phase mixing. Fast waves, in the absence of fine coronal structure, are more suited to powering emission from diffuse rather than compact sources; however, fast waves can be strongly localised by coronal waveguides, in which case focused energy is best transported to the chromosphere when waveguides are directly excited by the energy release. Conclusions: MHD waves pass an important test for inclusion in future flare models.

  3. Demonstration of Josephson effect submillimeter wave sources with increased power

    E-print Network

    Han, Siyuan; Bi, Baokang; Zhang, Wenxing; Lukens, J. E.

    1994-03-05

    A submillimeter wave source based on a new design using Josephson junction arrays has been developed and tested. The maximum rf power, delivered to a 68? load and detected on chip, was 47 ?W at 394 GHz. Significant power ...

  4. Energy Storage System Sizing for Smoothing Power Generation , P. Bydlowski

    E-print Network

    Boyer, Edmond

    . The life cycle cost of the ESS is analyzed according energy rating in case of supercapacitor technology. Keywords: Energy Storage System (ESS), power smoothing, Direct Wave Energy Converter, Supercapacitor, Power of supercapacitor technology. The life expectancy is also studied in order to determine a possible replacement

  5. Use of numerical wind-wave models for assessment of the offshore wave energy resource

    SciTech Connect

    Pontes, M.T. [INETI-ITE, Lisbon (Portugal); Barstow, S. [OCEANOR S.A., Trondheim (Norway); Bertotti, L.; Cavaleri, L. [ISDGM, Venice (Italy); Oliveira-Pires, H. [Inst. de Meteorologia, Lisbon (Portugal)

    1996-12-31

    In the last two decades the performance of numerical wind-wave models has improved considerably. Several models have been routinely producing since the mid 1980`s good quality wave estimates globally. The verifications of wind-wave models have mainly focused on the evaluation of the error of the significant wave height H{sub s} estimates. However for wave energy purposes the main parameters to be assessed are the wave power P{sub w} and the mean (energy) period T{sub e}. Since P{sub w} is proportional to H{sub s}{sup 2}T{sub e}, its expected error is much larger than for the single wave parameters. This paper summarizes the intercomparison of two wind-wave models against buoy data in the North Atlantic and the Mediterranean Sea to select the most suitable one for the construction of an Atlas of the wave energy resource in Europe. A full verification in the two basins of the selected model--the WAM model, implemented in the routine operation of the European Centre for Medium-Range Weather Forecasts--was then performed against buoy and satellite altimeter data. It was found that the WAM model accuracy is very good for offshore locations in the North Atlantic, but for the Mediterranean Sea the results are much less accurate probably due to a lower quality of the input wind fields.

  6. Use of numerical wind-wave models for assessment of the offshore wave energy resource

    SciTech Connect

    Pontes, M.T. [INETI-ITE, Lisbon (Portugal); Barstow, S. [OCEANOR S.A., Trondheim (Norway); Bertotti, L.; Cavaleri, L. [ISDGM, Venice (Italy); Oliveira-Pires, H. [Inst. de Meteorologia, Lisbon (Portugal)

    1997-08-01

    In the last two decades the performance of numerical wind-wave models has improved considerably. Several models have been routinely producing good quality wave estimates globally since the mid-1980s. The verifications of wind-wave models have mainly focused on the evaluation of the error of the significant wave height H{sub s} estimates. However, for wave energy purposes, the main parameters to be assessed are the wave power P{sub w} and the mean (energy) period T{sub e}. Since P{sub w} is proportional to H{sub s}{sup 2}T{sub e}, its expected error is much larger than for the single-wave parameters. This paper summarizes the intercomparison of two wind-wave models against buoy data in the North Atlantic and the Mediterranean Sea to select the most suitable one for the construction of an Atlas of the wave energy resource in European waters. A full verification in the two basins of the selected model--the WAM model, implemented in the routine operation of the European Centre for Medium-Range Weather Forecasts--was then performed against buoy and satellite altimeter data. It was found that the WAM model accuracy is very good for offshore locations in the North Atlantic; but for the Mediterranean Sea the results are much less accurate, probably due to a lower quality of the input wind fields.

  7. Analysis of Waves in the Near-Field of Wave Energy Converter Arrays through Stereo Video

    NASA Astrophysics Data System (ADS)

    Black, C.; Haller, M. C.

    2013-12-01

    Oregon State University conducted a series of laboratory experiments to measure and quantify the near-field wave effects caused within arrays of 3 and 5 Wave Energy Converters (WEC). As the waves and WECs interact, significant scattering and radiation occurs increasing/decreasing the wave heights as well as changing the direction the wave is traveling. These effects may vary based on the number of WECs within an array and their respective locations. The findings of this analysis will assist in selecting the WEC farm location and in improving WEC design. Analyzing the near-field waves will help determine the relative importance of absorption, scattering, and radiation as a function of the incident wave conditions and device performance. The WEC mooring system design specifications may also be impacted if the wave heights in the near-field are greater than expected. It is imperative to fully understand the near-field waves before full-scale WEC farms can be installed. Columbia Power Technologies' Manta served as the test WEC prototype on a 1 to 33 scale. Twenty-three wave gages measured the wave heights in both regular and real sea conditions at locations surrounding and within the WEC arrays. While these gages give a good overall picture of the water elevation behavior, it is difficult to resolve the complicated wave field within the WEC array using point gages. Here stereo video techniques are applied to extract the 3D water surface elevations at high resolution in order to reconstruct the multi-directional wave field in the near-field of the WEC array. The video derived wave information will also be compared against the wave gage data.

  8. Wave Energy Deposition in the Solar Corona

    NASA Astrophysics Data System (ADS)

    Van Doorsselaere, Tom; Goossens, Marcel; Verth, Gary; Soler, Roberto; Gijsen, Stief; Andries, Jesse

    Recently, a significant amount of transverse wave energy has been estimated propagating along solar atmospheric magnetic fields. However, these estimates have been made with the classic bulk Alfven wave model which assumes a homogeneous plasma. In this talk, the kinetic, magnetic, and total energy densities and the flux of energy are first computed for transverse MHD waves in one-dimensional cylindrical flux tube models with a piecewise constant density profile. There are fundamental deviations from the properties for classic bulk Alfven waves. (1) There is no local equipartition between kinetic and magnetic energy. (2) The flux of energy and the velocity of energy transfer have, in addition to a component parallel to the magnetic field, components in the planes normal to the magnetic field. (3) The energy densities and the flux of energy vary spatially, contrary to the case of classic bulk Alfven waves. This last property is then used to connect the energy flux in such a simple model to the energy flux in multiple flux tube systems. We use the plasma filling factor f to derive an ad-hoc formula for estimating the energy that is propagated in bundles of loops. We find that the energy flux in kink waves is lower than the energy computed from a bulk Alfven wave interpretation, by a factor that is (approximately) between f and 2f. We consider some geometric models to quantify this correction factor.

  9. Standing wave tube electro active polymer wave energy converter

    NASA Astrophysics Data System (ADS)

    Jean, Philippe; Wattez, Ambroise; Ardoise, Guillaume; Melis, C.; Van Kessel, R.; Fourmon, A.; Barrabino, E.; Heemskerk, J.; Queau, J. P.

    2012-04-01

    Over the past 4 years SBM has developed a revolutionary Wave Energy Converter (WEC): the S3. Floating under the ocean surface, the S3 amplifies pressure waves similarly to a Ruben's tube. Only made of elastomers, the system is entirely flexible, environmentally friendly and silent. Thanks to a multimodal resonant behavior, the S3 is capable of efficiently harvesting wave energy from a wide range of wave periods, naturally smoothing the irregularities of ocean wave amplitudes and periods. In the S3 system, Electro Active Polymer (EAP) generators are distributed along an elastomeric tube over several wave lengths, they convert wave induced deformations directly into electricity. The output is high voltage multiphase Direct Current with low ripple. Unlike other conventional WECs, the S3 requires no maintenance of moving parts. The conception and operating principle will eventually lead to a reduction of both CAPEX and OPEX. By integrating EAP generators into a small scale S3, SBM achieved a world first: direct conversion of wave energy in electricity with a moored flexible submerged EAP WEC in a wave tank test. Through an extensive testing program on large scale EAP generators, SBM identified challenges in scaling up to a utility grid device. French Government supports the consortium consisting of SBM, IFREMER and ECN in their efforts to deploy a full scale prototype at the SEMREV test center in France at the horizon 2014-2015. SBM will be seeking strategic as well as financial partners to unleash the true potentials of the S3 Standing Wave Tube Electro Active Polymer WEC.

  10. Wave energy devices with compressible volumes.

    PubMed

    Kurniawan, Adi; Greaves, Deborah; Chaplin, John

    2014-12-01

    We present an analysis of wave energy devices with air-filled compressible submerged volumes, where variability of volume is achieved by means of a horizontal surface free to move up and down relative to the body. An analysis of bodies without power take-off (PTO) systems is first presented to demonstrate the positive effects a compressible volume could have on the body response. Subsequently, two compressible device variations are analysed. In the first variation, the compressible volume is connected to a fixed volume via an air turbine for PTO. In the second variation, a water column separates the compressible volume from another volume, which is fitted with an air turbine open to the atmosphere. Both floating and bottom-fixed, axisymmetric, configurations are considered, and linear analysis is employed throughout. Advantages and disadvantages of each device are examined in detail. Some configurations with displaced volumes less than 2000?m(3) and with constant turbine coefficients are shown to be capable of achieving 80% of the theoretical maximum absorbed power over a wave period range of about 4?s. PMID:25484609

  11. Wave energy extraction by coupled resonant absorbers.

    PubMed

    Evans, D V; Porter, R

    2012-01-28

    In this article, a range of problems and theories will be introduced that will build towards a new wave energy converter (WEC) concept, with the acronym 'ROTA' standing for resonant over-topping absorber. First, classical results for wave power absorption for WECs constrained to operate in a single degree of freedom will be reviewed and the role of resonance in their operation highlighted. Emphasis will then be placed on how the introduction of further resonances can improve power take-off characteristics by extending the range of frequencies over which the efficiency is close to a theoretical maximum. Methods for doing this in different types of WECs will be demonstrated. Coupled resonant absorbers achieve this by connecting a WEC device equipped with its own resonance (determined from a hydrodynamic analysis) to a new system having separate mass/spring/damper characteristics. It is shown that a coupled resonant effect can be realized by inserting a water tank into a WEC, and this idea forms the basis of the ROTA device. In essence, the idea is to exploit the coupling between the natural sloshing frequencies of the water in the internal tank and the natural resonance of a submerged buoyant circular cylinder device that is tethered to the sea floor, allowing a rotary motion about its axis of attachment. PMID:22184664

  12. Wave energy devices with compressible volumes

    PubMed Central

    Kurniawan, Adi; Greaves, Deborah; Chaplin, John

    2014-01-01

    We present an analysis of wave energy devices with air-filled compressible submerged volumes, where variability of volume is achieved by means of a horizontal surface free to move up and down relative to the body. An analysis of bodies without power take-off (PTO) systems is first presented to demonstrate the positive effects a compressible volume could have on the body response. Subsequently, two compressible device variations are analysed. In the first variation, the compressible volume is connected to a fixed volume via an air turbine for PTO. In the second variation, a water column separates the compressible volume from another volume, which is fitted with an air turbine open to the atmosphere. Both floating and bottom-fixed, axisymmetric, configurations are considered, and linear analysis is employed throughout. Advantages and disadvantages of each device are examined in detail. Some configurations with displaced volumes less than 2000?m3 and with constant turbine coefficients are shown to be capable of achieving 80% of the theoretical maximum absorbed power over a wave period range of about 4?s. PMID:25484609

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

    E-print Network

    Wood, Stephen L.

    Application of wave generator theory to the development of a Wave Energy Converter by Maila Sepri approve the attached thesis Application of wave generator theory to the development of a Wave Energy Application of wave generator theory to the development of a Wave Energy Converter by Maila Sepri Principal

  14. Fundamental research on oscillating water column wave power absorbers

    SciTech Connect

    Maeda, H.; Kato, W.; Kinoshita, T.; Masuda, K.

    1985-03-01

    An oscillating water column (OWC) wave power absorber is one of the most promising devices, as well as the Salter Duck and the Clam. This paper presents a simple prediction method, in which the equivalent floating body approximation is used, for absorbing wave power characteristics of an oscillating water column device. The effects of the compressibility of air and inertia of an air turbine and electric generator on absorbed wave power are obtained by using the equivalent electric circuit concept. Both the experimental and theoretical studies are carried out in this paper.

  15. Energy in a String Wave

    ERIC Educational Resources Information Center

    Ng, Chiu-king

    2010-01-01

    When one end of a taut horizontal elastic string is shaken repeatedly up and down, a transverse wave (assume sine waveform) will be produced and travel along it. College students know this type of wave motion well. They know when the wave passes by, each element of the string will perform an oscillating up-down motion, which in mechanics is termed…

  16. On the Energy of Rotating Gravitational Waves

    E-print Network

    Bahram Mashhoon; James C. McClune; Enrique Chavez; Hernando Quevedo

    1996-09-06

    A class of solutions of the gravitational field equations describing vacuum spacetimes outside rotating cylindrical sources is presented. A subclass of these solutions corresponds to the exterior gravitational fields of rotating cylindrical systems that emit gravitational radiation. The properties of these rotating gravitational wave spacetimes are investigated. In particular, we discuss the energy density of these waves using the gravitational stress-energy tensor.

  17. What can wave energy learn from offshore oil and gas?

    PubMed

    Jefferys, E R

    2012-01-28

    This title may appear rather presumptuous in the light of the progress made by the leading wave energy devices. However, there may still be some useful lessons to be learnt from current 'offshore' practice, and there are certainly some awful warnings from the past. Wave energy devices and the marine structures used in oil and gas exploration as well as production share a common environment and both are subject to wave, wind and current loads, which may be evaluated with well-validated, albeit imperfect, tools. Both types of structure can be designed, analysed and fabricated using similar tools and technologies. They fulfil very different missions and are subject to different economic and performance requirements; hence 'offshore' design tools must be used appropriately in wave energy project and system design, and 'offshore' cost data should be adapted for 'wave' applications. This article reviews the similarities and differences between the fields and highlights the differing economic environments; offshore structures are typically a small to moderate component of field development cost, while wave power devices will dominate overall system cost. The typical 'offshore' design process is summarized and issues such as reliability-based design and design of not normally manned structures are addressed. Lessons learned from poor design in the past are discussed to highlight areas where care is needed, and wave energy-specific design areas are reviewed. Opportunities for innovation and optimization in wave energy project and device design are discussed; wave energy projects must ultimately compete on a level playing field with other routes to low CO? energy and/or energy efficiency. This article is a personal viewpoint and not an expression of a ConocoPhillips position. PMID:22184670

  18. Transmission of wave energy in curved ducts

    NASA Technical Reports Server (NTRS)

    Rostafinski, W.

    1973-01-01

    A formation of wave energy flow was developed for motion in curved ducts. A parametric study over a range of frequencies determined the ability of circular bends to transmit energy for the case of perfectly rigid walls.

  19. The Force of a Tsunami on a Wave Energy Converter

    E-print Network

    O'Brien, Laura; Renzi, Emiliano; Dutykh, Denys; Dias, Frédéric

    2012-01-01

    With an increasing emphasis on renewable energy resources, wave power technology is fast becoming a realistic solution. However, the recent tsunami in Japan was a harsh reminder of the ferocity of the ocean. It is known that tsunamis are nearly undetectable in the open ocean but as the wave approaches the shore its energy is compressed creating large destructive waves. The question posed here is whether a nearshore wave energy converter (WEC) could withstand the force of an incoming tsunami. The analytical 3D model of Renzi & Dias (2012) developed within the framework of a linear theory and applied to an array of fixed plates is used. The time derivative of the velocity potential allows the hydrodynamic force to be calculated.

  20. Energy 101: Concentrating Solar Power

    ScienceCinema

    None

    2013-05-29

    From towers to dishes to linear mirrors to troughs, concentrating solar power (CSP) technologies reflect and collect solar heat to generate electricity. A single CSP plant can generate enough power for about 90,000 homes. This video explains what CSP is, how it works, and how systems like parabolic troughs produce renewable power. For more information on the Office of Energy Efficiency and Renewable Energy's CSP research, see the Solar Energy Technology Program's Concentrating Solar Power Web page at http://www1.eere.energy.gov/solar/csp_program.html.

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

    E-print Network

    Kalantari, Nader

    2013-01-01

    follower and common emitter amplifiers and using HBT devicescommon emitter as a single transconductance, g m , Figure 3.1: Circuit illustration of a wideband, tapered constructive wave power amplifier.

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

    E-print Network

    Kalantari, Nader

    2013-01-01

    emitter follower and common emitter amplifiers and using HBTand common emitter as a single transconductance, g m , Figure 3.1: Circuit illustration of a wideband, tapered constructive wave power amplifier.

  3. Wave energy potential in the Baltic Sea and the Danish part of the North Sea, with reflections on the Skagerrak

    Microsoft Academic Search

    Urban Henfridsson; Viktoria Neimane; Kerstin Strand; Robert Kapper; Hans Bernhoff; Oskar Danielsson; Mats Leijon; Jan Sundberg; Karin Thorburn; Ellerth Ericsson; Karl Bergman

    2007-01-01

    Wave power, along with renewable energy-generating sources like tides and streams, is underestimated considering its advantageous physical properties and predictability. This paper examines possible examples of wave power installations in the Baltic Sea and the Danish part of the North Sea. Hindcasting data is used allowing estimations of wave energy generated and results show promising areas in the North Sea,

  4. End-boundary sheath potential, Langmuir waves, electron and ion energy distribution in the low pressure DC powered Non-ambipolar Electron Plasma

    NASA Astrophysics Data System (ADS)

    Chen, Lee; Chen, Zhiying; Funk, Merritt

    2013-09-01

    The non-ambipolar electron plasma (NEP) is heated by electron beam extracted from the electron-source Ar plasma through a dielectric injector by an accelerator located inside NEP. NEP pressure is in the 1-3mTorr range of N2 and its accelerator voltage varied from VA = + 80 to VA = + 600V. The non-ambipolar beam-current injected into NEP is in the range of 10s Acm-2 and it heats NEP through beam-plasma instabilities. Its EED f has a Maxwellian bulk followed by a broad energy-continuum connecting to the most energetic group with energies above the beam-energy. The remnant of the injected electron-beam power terminates at the NEP end-boundary floating-surface setting up sheath potentials from VS = 80 to VS = 580V in response to the applied values of VA. The floating-surface is bombarded by a space-charge neutral plasma-beam whose IED f is near mono-energetic. When the injected electron-beam power is adequately damped by NEP, its end-boundary floating-surface VS can be linearly controlled at almost 1:1 ratio by VA. NEP does not have an electron-free sheath; its ``sheath'' is a widen presheath that consists of a thermal presheath followed by an ``anisotropic'' presheath, leading up to the end-boundary floating-surface. Its ion-current of the plasma-beam is much higher than what a conventional thermal presheath can supply. If the NEP parameters cannot damp the electron beam power sufficiently, VS will collapse and becomes irresponsive to VA.

  5. Stochastic Control of Inertial Sea Wave Energy Converter

    PubMed Central

    Mattiazzo, Giuliana; Giorcelli, Ermanno

    2015-01-01

    The ISWEC (inertial sea wave energy converter) is presented, its control problems are stated, and an optimal control strategy is introduced. As the aim of the device is energy conversion, the mean absorbed power by ISWEC is calculated for a plane 2D irregular sea state. The response of the WEC (wave energy converter) is driven by the sea-surface elevation, which is modeled by a stationary and homogeneous zero mean Gaussian stochastic process. System equations are linearized thus simplifying the numerical model of the device. The resulting response is obtained as the output of the coupled mechanic-hydrodynamic model of the device. A stochastic suboptimal controller, derived from optimal control theory, is defined and applied to ISWEC. Results of this approach have been compared with the ones obtained with a linear spring-damper controller, highlighting the capability to obtain a higher value of mean extracted power despite higher power peaks. PMID:25874267

  6. Stochastic control of inertial sea wave energy converter.

    PubMed

    Raffero, Mattia; Martini, Michele; Passione, Biagio; Mattiazzo, Giuliana; Giorcelli, Ermanno; Bracco, Giovanni

    2015-01-01

    The ISWEC (inertial sea wave energy converter) is presented, its control problems are stated, and an optimal control strategy is introduced. As the aim of the device is energy conversion, the mean absorbed power by ISWEC is calculated for a plane 2D irregular sea state. The response of the WEC (wave energy converter) is driven by the sea-surface elevation, which is modeled by a stationary and homogeneous zero mean Gaussian stochastic process. System equations are linearized thus simplifying the numerical model of the device. The resulting response is obtained as the output of the coupled mechanic-hydrodynamic model of the device. A stochastic suboptimal controller, derived from optimal control theory, is defined and applied to ISWEC. Results of this approach have been compared with the ones obtained with a linear spring-damper controller, highlighting the capability to obtain a higher value of mean extracted power despite higher power peaks. PMID:25874267

  7. Wave energy converter effects on wave propagation: A sensitivity study in Monterey Bay, CA

    NASA Astrophysics Data System (ADS)

    Chang, G.; Jones, C. A.; Roberts, J.; Magalen, J.; Ruehl, K.; Chartrand, C.

    2014-12-01

    The development of renewable offshore energy in the United States is growing rapidly and wave energy is one of the largest resources currently being evaluated. The deployment of wave energy converter (WEC) arrays required to harness this resource could feasibly number in the hundreds of individual devices. The WEC arrays have the potential to alter nearshore wave propagation and circulation patterns and ecosystem processes. As the industry progresses from pilot- to commercial-scale it is important to understand and quantify the effects of WECs on the natural nearshore processes that support a local, healthy ecosystem. To help accelerate the realization of commercial-scale wave power, predictive modeling tools have been developed and utilized to evaluate the likelihood of environmental impact. At present, direct measurements of the effects of different types of WEC arrays on nearshore wave propagation are not available; therefore wave model simulations provide the groundwork for investigations of the sensitivity of model results to prescribed WEC characteristics over a range of anticipated wave conditions. The present study incorporates a modified version of an industry standard wave modeling tool, SWAN (Simulating WAves Nearshore), to simulate wave propagation through a hypothetical WEC array deployment site on the California coast. The modified SWAN, referred to as SNL-SWAN, incorporates device-specific WEC power take-off characteristics to more accurately evaluate a WEC device's effects on wave propagation. The primary objectives were to investigate the effects of a range of WEC devices and device and array characteristics (e.g., device spacing, number of WECs in an array) on nearshore wave propagation using SNL-SWAN model simulations. Results showed that significant wave height was most sensitive to variations in WEC device type and size and the number of WEC devices in an array. Locations in the lee centerline of the arrays in each modeled scenario showed the largest potential changes in wave height. The SNL-SWAN model simulations for various WEC devices provide the basis for a solid model understanding, giving the confidence necessary for future WEC evaluations.

  8. Environmental assessment for the Satellite Power System (SPS): studies of honey bees exposed to 2. 45 GHz continuous-wave electromagnetic energy

    SciTech Connect

    Gary, N E; Westerdahl, B B

    1980-12-01

    A system for small animal exposure was developed for treating honey bees, Apis mellifera L., in brood and adult stages, with 2.45 GHz continuous wave microwaves at selected power densities and exposure times. Post-treatment brood development was normal and teratological effects were not detected at exposures of 3 to 50 mw/cm/sup 2/ for 30 minutes. Post-treatment survival, longevity, orientation, navigation, and memory of adult bees were also normal after exposures of 3 to 50 mw/cm/sup 2/ for 30 minutes. Post-treatment longevity of confined bees in the laboratory was normal after exposures of 3 to 50 mw/cm/sup 2/ for 24 hours. Thermoregulation of brood nest, foraging activity, brood rearing, and social interaction were not affected by chronic exposure to 1 mw/cm/sup 2/ during 28 days. In dynamic behavioral bioassays the frequency of entry and duration of activity of unrestrained, foraging adult bees was identical in microwave-exposed (5 to 40 mw/cm/sup 2/) areas versus control areas.

  9. Wave spectral energy variability in the northeast Peter D. Bromirski

    E-print Network

    Bromirski, Peter D.

    Wave spectral energy variability in the northeast Pacific Peter D. Bromirski Integrative January 2005; published 8 March 2005. [1] The dominant characteristics of wave energy variability] s wave spectral energy components are considered separately. Empirical orthogonal function (EOF) analyses

  10. Deflagration Wave with Radiative Energy Transport

    NASA Astrophysics Data System (ADS)

    Tamba, Moritake; Niu, Keishiro

    1982-02-01

    Numerical calculations are carried out to analyze the spatial structures of the stationary deflagration waves formed in the stab targets. In the analysis, the radiative energy transport is taken into account. The profiles of the radiative energy flux differ depending on the states of the outer-layer aluminium of the target (solid or plasma). However the radiative energy transport plays a negligible role in the deflagration-wave structures formed by the light-ion beam.

  11. Wave Energy Resource Analysis for Use in Wave Energy Conversion 

    E-print Network

    Pastor, J.; Liu, Y.; Dou, Y.

    2014-01-01

    the naturally available and technically recoverable resource in a given location. The methodology was developed by the EPRI and uses a modified Gamma spectrum that interoperates hindcast sea state parameter data produced by NOAA's Wave watch III. This Gamma...

  12. Wave Energy Resource Analysis for Use in Wave Energy Conversion

    E-print Network

    Pastor, J.; Liu, Y.; Dou, Y.

    2014-01-01

    spectrum is dependent on the calibration of two variables relating to the spectral width parameter and the spectral peakedness parameter. Minor changes were implemented by the author to increase accuracy in formulating wave length. Overall this methodology...

  13. The electromagnetic spectrum : waves of energy

    NSDL National Science Digital Library

    Tracy Coulson

    2002-01-01

    In this lesson, students will (1) understand that the sun energy is transferred to Earth by electromagnetic waves, which are transverse waves, (2) understand that there are eight main types of electromagnetic waves, classified on the electromagnetic spectrum according to their wavelengths, and (3) understand how each of the types of electromagnetic radiation is used or found in our everyday lives. This would be a suitable activity for small groups.

  14. Counting energy packets in the electromagnetic wave

    E-print Network

    Stefan Popescu; Bernhard Rothenstein

    2007-05-18

    We discuss the concept of energy packets in respect to the energy transported by electromagnetic waves and we demonstrate that this physical quantity can be used in physical problems involving relativistic effects. This refined concept provides results compatible to those obtained by simpler definition of energy density when relativistic effects apply to the free electromagnetic waves. We found this concept further compatible to quantum theory perceptions and we show how it could be used to conciliate between different physical approaches including the classical electromagnetic wave theory, the special relativity and the quantum theories.

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

    E-print Network

    Qing-Guo Huang; Sai Wang

    2015-02-09

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

  16. Multistable chain for ocean wave vibration energy harvesting

    NASA Astrophysics Data System (ADS)

    Harne, R. L.; Schoemaker, M. E.; Wang, K. W.

    2014-03-01

    The heaving of ocean waves is a largely untapped, renewable kinetic energy resource. Conversion of this energy into electrical power could integrate with solar technologies to provide for round-the-clock, portable, and mobile energy supplies usable in a wide variety of marine environments. However, the direct drive conversion methodology of gridintegrated wave energy converters does not efficiently scale down to smaller, portable architectures. This research develops an alternative power conversion approach to harness the extraordinarily large heaving displacements and long oscillation periods as an excitation source for an extendible vibration energy harvesting chain. Building upon related research findings and engineering insights, the proposed system joins together a series of dynamic cells through bistable interfaces. Individual impulse events are generated as the inertial mass of each cell is pulled across a region of negative stiffness to induce local snap through dynamics; the oscillating magnetic inertial mass then generates current in a coil which is connected to energy harvesting circuitry. It is shown that linking the cells into a chain transmits impulses through the system leading to cascades of vibration and enhancement of electrical energy conversion from each impulse event. This paper describes the development of the multistable chain and ways in which realistic design challenges were addressed. Numerical modeling and corresponding experiments demonstrate the response of the chain due to slow and large amplitude input motion. Lastly, experimental studies give evidence that energy conversion efficiency of the chain for wave energy conversion is much higher than using an equal number of cells without connections.

  17. Energy-momentum relation for solitary waves of relativistic wave equations

    E-print Network

    T. V. Dudnikova; A. I. Komech; H. Spohn

    2005-08-23

    Solitary waves of relativistic invariant nonlinear wave equation with symmetry group U(1) are considered. We prove that the energy-momentum relation for spherically symmetric solitary waves coincides with the Einstein energy-momentum relation for point particles.

  18. Direct Drive Wave Energy Buoy – 33rd scale experiment

    SciTech Connect

    Rhinefrank, Kenneth E. [Columbia Power Technologies, Inc.; Lenee-Bluhm, Pukha [Columbia Power Technologies, Inc.; Prudell, Joseph H. [Columbia Power Technologies, Inc.; Schacher, Alphonse A.; Hammagren, Erik J.; Zhang, Zhe [Columbia Power Technologies, Inc.

    2013-07-29

    Columbia Power Technologies (ColPwr) and Oregon State University (OSU) jointly conducted a series of tests in the Tsunami Wave Basin (TWB) at the O.H. Hinsdale Wave Research Laboratory (HWRL). These tests were run between November 2010 and February 2011. Models at 33rd scale representing Columbia Power’s Manta series Wave Energy Converter (WEC) were moored in configurations of one, three and five WEC arrays, with both regular waves and irregular seas generated. The primary research interest of ColPwr is the characterization of WEC response. The WEC response will be investigated with respect to power performance, range of motion and generator torque/speed statistics. The experimental results will be used to validate a numerical model. The primary research interests of OSU include an investigation into the effects of the WEC arrays on the near- and far-field wave propagation. This report focuses on the characterization of the response of a single WEC in isolation. To facilitate understanding of the commercial scale WEC, results will be presented as full scale equivalents.

  19. Wave energy budget analysis in the Earth's radiation belts uncovers a missing energy.

    PubMed

    Artemyev, A V; Agapitov, O V; Mourenas, D; Krasnoselskikh, V V; Mozer, F S

    2015-01-01

    Whistler-mode emissions are important electromagnetic waves pervasive in the Earth's magnetosphere, where they continuously remove or energize electrons trapped by the geomagnetic field, controlling radiation hazards to satellites and astronauts and the upper-atmosphere ionization or chemical composition. Here, we report an analysis of 10-year Cluster data, statistically evaluating the full wave energy budget in the Earth's magnetosphere, revealing that a significant fraction of the energy corresponds to hitherto generally neglected very oblique waves. Such waves, with 10 times smaller magnetic power than parallel waves, typically have similar total energy. Moreover, they carry up to 80% of the wave energy involved in wave-particle resonant interactions. It implies that electron heating and precipitation into the atmosphere may have been significantly under/over-valued in past studies considering only conventional quasi-parallel waves. Very oblique waves may turn out to be a crucial agent of energy redistribution in the Earth's radiation belts, controlled by solar activity. PMID:25975615

  20. Wave energy budget analysis in the Earth's radiation belts uncovers a missing energy

    PubMed Central

    Artemyev, A.V.; Agapitov, O.V.; Mourenas, D.; Krasnoselskikh, V.V.; Mozer, F.S.

    2015-01-01

    Whistler-mode emissions are important electromagnetic waves pervasive in the Earth's magnetosphere, where they continuously remove or energize electrons trapped by the geomagnetic field, controlling radiation hazards to satellites and astronauts and the upper-atmosphere ionization or chemical composition. Here, we report an analysis of 10-year Cluster data, statistically evaluating the full wave energy budget in the Earth's magnetosphere, revealing that a significant fraction of the energy corresponds to hitherto generally neglected very oblique waves. Such waves, with 10 times smaller magnetic power than parallel waves, typically have similar total energy. Moreover, they carry up to 80% of the wave energy involved in wave–particle resonant interactions. It implies that electron heating and precipitation into the atmosphere may have been significantly under/over-valued in past studies considering only conventional quasi-parallel waves. Very oblique waves may turn out to be a crucial agent of energy redistribution in the Earth's radiation belts, controlled by solar activity. PMID:25975615

  1. Guidelines in Wave Energy Conversion System Design

    E-print Network

    Guiberteau, K. L.; Liu, Y.; Lee, J.; Kozman, T.

    2014-01-01

    This paper presents an investigational study on wave energy converters (WECs). The types of WEC available from the market are studied first. The design considerations for implementing a WEC in the Gulf of Mexico (GOM) are then evaluated...

  2. Wave Energy Development in Oregon Licensing & Permitting Requirements

    E-print Network

    July 09 Wave Energy Development in Oregon Licensing & Permitting Requirements Prepared by Pacific Energy Ventures on behalf of the Oregon Wave Energy Trust w w w . o r e g o n w a v e . o r g #12;This study was commissioned by Oregon Wave Energy Trust. Oregon Wave Energy Trust is funded by the Oregon

  3. The Power of Energy Storage

    E-print Network

    Sadoulet, Elisabeth

    the efficiency of the grid and the value of renewable energy. Finally, energy storage can eliminate someThe Power of Energy Storage How to Increase Deployment in California to Reduce Greenhouse Gas Emissions July 2010 #12;About this Report This policy paper is the sixth in a series of reports on how

  4. Renewable Energy Powers Renewable Energy Lab, Employees

    E-print Network

    . NREL is also using solar energy for auxiliary purposes such as powering streetlights, water pumps, they may cost more. But as more people try renewable energy, prices will come down. Just look at computers. This has steadily lowered costs to the point where wind energy is within reach of many consumers. The price

  5. Design Methodology for a SEAREV Wave Energy Marie Ruellan, Hamid BenAhmed, Bernard Multon, Christophe Josset, Aurelien Babarit,

    E-print Network

    Boyer, Edmond

    1 Design Methodology for a SEAREV Wave Energy Converter Marie Ruellan, Hamid BenAhmed, Bernard by presenting two power take-off (PTO) technologies for the SEAREV wave energy converter (WEC) followed technologies in- tended to transform wave energy into electricity. The types of systems are twofold

  6. Water Power for a Clean Energy Future (Fact Sheet)

    SciTech Connect

    Not Available

    2010-07-01

    Water power technologies harness energy from rivers and oceans to generate electricity for the nation's homes and businesses, and can help the United States meet its pressing energy, environmental, and economic challenges. Water power technologies; fall into two broad categories: conventional hydropower and marine and hydrokinetic technologies. Conventional hydropower uses dams or impoundments to store river water in a reservoir. Marine and hydrokinetic technologies capture energy from waves, tides, ocean currents, free-flowing rivers, streams, and ocean thermal gradients.

  7. Ocean Wave Energy Conversion - A Survey

    Microsoft Academic Search

    A. Muetze; J. G. Vining

    2006-01-01

    Ocean energy conversion has been of interest for many years. Recent developments such as concern over global warming have renewed interest in the topic. This paper gives a systematic and comprehensive overview of wave energy converters (WEC) as opposed to ocean current energy converters. The point absorber and oscillating water column WEC devices are addressed with regards to commercial prospects,

  8. Reactive Power from Distributed Energy

    SciTech Connect

    Kueck, John; Kirby, Brendan; Rizy, Tom; Li, Fangxing; Fall, Ndeye

    2006-12-15

    Distributed energy is an attractive option for solving reactive power and distribution system voltage problems because of its proximity to load. But the cost of retrofitting DE devices to absorb or produce reactive power needs to be reduced. There also needs to be a market mechanism in place for ISOs, RTOs, and transmission operators to procure reactive power from the customer side of the meter where DE usually resides. (author)

  9. The Power of Energy

    NSDL National Science Digital Library

    Diana Congden

    2012-06-14

    Have you ever wondered how energy changes from one form to another? How you can put food in microwave, and seconds later it is hot? What happens between the time you plug in a TV and you see a picture? Students will take a deeper look into energy. What are all of the kinds of energy that help an object work? This lesson is a fun way to involve kids in their learning and include technology to present.

  10. Energy, A Crisis in Power.

    ERIC Educational Resources Information Center

    Holdren, John; Herrera, Philip

    The demand of Americans for more and more power, particularly electric power, contrasted by the deep and growing concern for the environment and a desire by private citizens to participate in the public decisions that affect the environment is the dilemma explored in this book. Part One by John Holdren, offers a scientist's overview of the energy…

  11. Wave breaking onset and spectral distribution of energy loss due to laboratory generated breaking waves

    Microsoft Academic Search

    Zhigang Tian; Marc Perlin; Wooyoung Choi

    2009-01-01

    A study of wave breaking onset and energy loss due to wave breaking is presented. A global wave steepness parameter that accounts for spectral amplitude shape change is proposed. This parameter has a threshold of 0.25 for wave breaking onset and it correlated strongly with breaking energy loss. It exhibits reduced dependence on the shape of the wave spectrum, and

  12. Wind power and other energy options

    Microsoft Academic Search

    Inglis

    1979-01-01

    Past experience with wind power is considered along with the mechanics of wind energy conversion, small wind-power installations, large wind-power machines and installations, other solar-related energy sources, geophysical energy sources, nuclear power from fission, nuclear power from fusion, a comparison of dollar costs of wind power and nuclear power, social costs of wind power and nuclear power, and the choice

  13. Wind power and other energy options

    Microsoft Academic Search

    D. R. Inglis

    1978-01-01

    Past experience with wind power is considered along with the mechanics of wind energy conversion, small wind-power installations, large wind-power machines and installations, other solar-related energy sources, geophysical energy sources, nuclear power from fission, nuclear power from fusion, a comparison of dollar costs of wind power and nuclear power, social costs of wind power and nuclear power, and the choice

  14. Generation of high-power nanosecond pulses in a relativistic backward-wave oscillator in the regime of spatial accumulation of energy

    Microsoft Academic Search

    K. V. Afanasyev; N. M. Bykov; V. P. Gubanov; A. A. Elchaninov; A. I. Klimov; S. D. Korovin; V. V. Rostov; A. S. Stepchenko

    2006-01-01

    We study the generation of electromagnetic pulses with a carrier frequency of 3.7 GHz in a relativistic backward-wave oscillator\\u000a with a long slow-wave system in the superradiance regime of super-radiation for a magnetic induction of 0.2 T (below the cyclotron\\u000a resonance). To decrease transverse velocities of the electrons, we use decompression of a hollow electron beam. Decompression\\u000a in combination with

  15. PHYSICAL REVIEW E 89, 023003 (2014) Energy flux measurement from the dissipated energy in capillary wave turbulence

    E-print Network

    Falcon, Eric

    2014-01-01

    dissipated by capillary waves is also measured and found to increase nonlinearly with the mean power injectedPHYSICAL REVIEW E 89, 023003 (2014) Energy flux measurement from the dissipated energy in capillary wave turbulence Luc Deike, Michael Berhanu, and Eric Falcon Univ. Paris Diderot, Sorbonne Paris Cit

  16. Coordinated control and network integration of wave power farms 

    E-print Network

    Nambiar, Anup Jayaprakash

    2012-11-29

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

  17. Theoretical modelling of two wave-power devices

    E-print Network

    Lovas, Stéphanie

    2010-01-01

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

  18. Simulation of High Power Electromagnetic Wave Heating in the ITER Burning Plasma

    SciTech Connect

    Jaeger, Erwin Frederick [ORNL; Berry, Lee A [ORNL; D'Azevedo, Ed F [ORNL; Barrett, Richard F [ORNL; Ahern, Sean [ORNL; Swain, David W [ORNL; Batchelor, Donald B [ORNL; Harvey, R. W. [CompX, Del Mar, CA; Myra, J. R. [Lodestar Research Corporation; D'Ippolito, D. A. [Lodestar Research Corporation; Phillips, Cynthia [Princeton Plasma Physics Laboratory (PPPL); Valeo, Dr Ernest [Princeton Plasma Physics Laboratory (PPPL); Smithe, D. N. [Tech-X Corporation; Bonoli, P. T. [Massachusetts Institute of Technology (MIT); Wright, J. C. [Massachusetts Institute of Technology (MIT); Choi, M. [General Atomics

    2008-01-01

    The next step toward fusion as a practical energy source is the design and construction of ITER [R. Aymar, V. A. Chuyanov, M. Huguet, Y. Shimomura, ITER Joint Central Team, ITER Home Teams, Nucl. Fusion 41, 1301 (2001)], a device capable of producing and controlling the high performance plasma required for self-sustaining fusion reactions, i.e. "burning plasma." ITER relies in part on ion-cyclotron radio frequency power to heat the deuterium and tritium fuel to fusion temperatures. In order to heat effectively, the radio frequency wave fields must couple efficiently to the dense core plasma. Calculations in this paper support the argument that this will be the case. Three dimensional full-wave simulations show that fast magnetosonic waves in ITER propagate radially inward with strong central focusing and little toroidal spreading. Energy deposition, current drive, and plasma flow are all highly localized near the plasma center. Very high resolution, two dimensional calculations reveal the presence of mode conversion layers, where fast waves can be converted to slow ion cyclotron waves. When minority ions such as deuterium or helium-3 are used to damp the launched waves, these ions can be accelerated to high energies, forming supra-thermal tails that significantly affect the wave propagation and absorption. By neglecting the toroidal localization of the waves and the finite radial excursion of the energetic particle orbits, the quasilinear evolution of these supra-thermal ion tails can be simulated self-consistently in one spatial dimension and two velocity dimensions.

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

    SciTech Connect

    Chertok, Allan

    2013-01-31

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

  20. Artificial reef effect and fouling impacts on offshore wave power foundations and buoys - a pilot study

    NASA Astrophysics Data System (ADS)

    Langhamer, Olivia; Wilhelmsson, Dan; Engström, Jens

    2009-04-01

    Little is known about the effects of offshore energy installations on the marine environment, and further research could assist in minimizing environmental risks as well as in enhancing potential positive effects on the marine environment. While biofouling on marine energy conversion devices on one hand has the potential to be an engineering concern, these structures can also affect biodiversity by functioning as artificial reefs. The Lysekil Project is a test park for wave power located at the Swedish west coast. Here, buoys acting as point absorbers on the surface are connected to generators anchored on concrete foundations on the seabed. In this study we investigated the colonisation of foundations by invertebrates and fish, as well as fouling assemblages on buoys. We examined the influence of surface orientation of the wave power foundations on epibenthic colonisation, and made observations of habitat use by fish and crustaceans during three years of submergence. We also examined fouling assemblages on buoys and calculated the effects of biofouling on the energy absorption of the wave power buoys. On foundations we demonstrated a succession in colonisation over time with a higher degree of coverage on vertical surfaces. Buoys were dominated by the blue mussel Mytilus edulis. Calculations indicated that biofouling have no significant effect in the energy absorption on a buoy working as a point absorber. This study is the first structured investigation on marine organisms associated with wave power devices.

  1. Solar energy power generation system

    SciTech Connect

    Nilsson, J.E.; Cochran, C.D.

    1986-05-06

    A solar energy power generation system is described which consists of: (a) means for collecting and concentrating solar energy; (b) heat storage means; (c) Stirling engine means for producing power; (d) first heat transfer means for receiving the concentrated solar energy and for transferring heat to the heat storage means; and (e) second heat transfer means for controllably transferring heat from the storage means to the Stirling engine means and including a discharge heat pipe means for transferring heat to the Stirling engine means and further including means for inserting and withdrawing the discharge heat pipe means into and out of the heat storage means.

  2. Soft Capacitors for Wave Energy Harvesting

    E-print Network

    Karsten Ahnert; Markus Abel; Matthias Kollosche; Per Jørgen Jørgensen; Guggi Kofod

    2011-10-14

    Wave energy harvesting could be a substantial renewable energy source without impact on the global climate and ecology, yet practical attempts have struggle d with problems of wear and catastrophic failure. An innovative technology for ocean wave energy harvesting was recently proposed, based on the use of soft capacitors. This study presents a realistic theoretical and numerical model for the quantitative characterization of this harvesting method. Parameter regio ns with optimal behavior are found, and novel material descriptors are determined which simplify analysis dramatically. The characteristics of currently ava ilable material are evaluated, and found to merit a very conservative estimate of 10 years for raw material cost recovery.

  3. Radiative Energy Addition behind a Shock Wave

    Microsoft Academic Search

    Ronald G. Rehm

    1968-01-01

    Monochromatic radiation propagating in a direction opposite to that of a uniform, one-dimensional shock wave is absorbed throughout the region behind the shock front. Euler's equations for unsteady flow with energy addition and the macroscopic equation for radiative transfer neglecting emission are used to describe the motion. Behind the shock front it is assumed that the energy added to a

  4. Wave Energy Ecological Effects Workshop page 1 of 4 Ecological Effects of Wave Energy Development in the Pacific Northwest

    E-print Network

    Wright, Dawn Jeannine

    Wave Energy Ecological Effects Workshop page 1 of 4 Ecological Effects of Wave Energy Development the capacity to harvest wave energy off its coast as a clean, renewable resource. An important part of moving this agenda forward must include understanding the potential effects of wave energy technology

  5. Research and Technology in Wave Energy for Electric Mobility

    E-print Network

    Frandsen, Jannette B.

    Research and Technology in Wave Energy for Electric Mobility Reza Ghorbani Assistant Professor marine energy resources that are available for our utilization. These include wave energy, energy generated by ocean current and energy extraction through ocean thermal conversion (OTEC). For wave energy

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

    DOEpatents

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

    1999-01-01

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

  7. High-power continuous-wave quantum cascade lasers

    Microsoft Academic Search

    J. Faist; A. Tredicucci; F. Capasso; C. Sirtori; D. L. Sivco; J. N. Baillargeon; A. L. Hutchinson; A. Y. Cho

    1998-01-01

    High-power continuous-wave (CW) laser action is reported for a GaInAs-AlInAs quantum cascade structure operating in the mid-infrared (?≃5 ?m). Gain optimization and reduced heating effects have been achieved by employing a modulation-doped funnel injector with a three-well vertical-transition active region and by adopting InP as the waveguide cladding material to improve thermal dissipation and lateral conductance. A CW optical power

  8. Optimisation and comparison of integrated models of direct-drive linear machines for wave energy conversion 

    E-print Network

    Crozier, Richard Carson

    2014-06-30

    Combined electrical and structural models of five types of permanent magnet linear electrical machines suitable for direct-drive power take-off on wave energy applications are presented. Electromagnetic models were ...

  9. 2007 Survey of Energy Resources World Energy Council 2007 Wave Energy COUNTRY NOTES

    E-print Network

    2007 Survey of Energy Resources World Energy Council 2007 Wave Energy 550 COUNTRY NOTES The following Country Notes on Wave Energy have been compiled by Tom Thorpe and the Editors. Every effort has been made to be comprehensive by making contact with all known wave energy developers. However

  10. Scandinavian power and energy resources

    Microsoft Academic Search

    Papamarcos

    1984-01-01

    Countries generally included in the Scandinavian grouping vary considerably in their energy resources, from Norway which is more than self-sufficient to Denmark which is almost wholly dependent on imported fuels. In electric power generation the variety is extreme, with Norway fully self-sufficient in hydro power, and Denmark wholly dependent on imported fuel for its fossil-fired generating stations. Only Sweden and

  11. Instantaneous power and threshold in continuous wave quantum cascade lasers

    Microsoft Academic Search

    A. J. Hoffman; P. X. Braun; M. D. Escarra; S. S. Howard; K. J. Franz; Xiaojun Wang; Jen-Yu Fan; C. Gmachl

    2009-01-01

    Using low-duty cycle pulses superimposed on a DC current, we determine the type of power roll-over and obtain the instantaneous threshold current, current efficiency and core temperature of a quantum-cascade laser in continuous wave operation.

  12. Chromospheric alfvenic waves strong enough to power the solar wind.

    PubMed

    De Pontieu, B; McIntosh, S W; Carlsson, M; Hansteen, V H; Tarbell, T D; Schrijver, C J; Title, A M; Shine, R A; Tsuneta, S; Katsukawa, Y; Ichimoto, K; Suematsu, Y; Shimizu, T; Nagata, S

    2007-12-01

    Alfvén waves have been invoked as a possible mechanism for the heating of the Sun's outer atmosphere, or corona, to millions of degrees and for the acceleration of the solar wind to hundreds of kilometers per second. However, Alfvén waves of sufficient strength have not been unambiguously observed in the solar atmosphere. We used images of high temporal and spatial resolution obtained with the Solar Optical Telescope onboard the Japanese Hinode satellite to reveal that the chromosphere, the region sandwiched between the solar surface and the corona, is permeated by Alfvén waves with strong amplitudes on the order of 10 to 25 kilometers per second and periods of 100 to 500 seconds. Estimates of the energy flux carried by these waves and comparisons with advanced radiative magnetohydrodynamic simulations indicate that such Alfvén waves are energetic enough to accelerate the solar wind and possibly to heat the quiet corona. PMID:18063784

  13. Energy-momentum Density of Gravitational Waves

    E-print Network

    Amir M. Abbassi; Saeed Mirshekari

    2014-11-29

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

  14. Electromagnetic wave energy conversion research

    NASA Technical Reports Server (NTRS)

    Bailey, R. L.; Callahan, P. S.

    1975-01-01

    Known electromagnetic wave absorbing structures found in nature were first studied for clues of how one might later design large area man-made radiant-electric converters. This led to the study of the electro-optics of insect dielectric antennae. Insights were achieved into how these antennae probably operate in the infrared 7-14um range. EWEC theoretical models and relevant cases were concisely formulated and justified for metal and dielectric absorber materials. Finding the electromagnetic field solutions to these models is a problem not yet solved. A rough estimate of losses in metal, solid dielectric, and hollow dielectric waveguides indicates future radiant-electric EWEC research should aim toward dielectric materials for maximum conversion efficiency. It was also found that the absorber bandwidth is a theoretical limitation on radiant-electric conversion efficiency. Ideally, the absorbers' wavelength would be centered on the irradiating spectrum and have the same bandwith as the irradiating wave. The EWEC concept appears to have a valid scientific basis, but considerable more research is needed before it is thoroughly understood, especially for the complex randomly polarized, wide band, phase incoherent spectrum of the sun. Specific recommended research areas are identified.

  15. Energy flux of timeharmonic waves in anisotropic dissipative media

    E-print Network

    Cerveny, Vlastislav

    Energy flux of time­harmonic waves in anisotropic dissipative media Vlastislav Ÿ Cerven/transmission problem. Energy flux quantities related to the summary wavefield, composed of several waves, are derived in the summary energy flux in addition to the energy fluxes of the individual waves. The interaction energy

  16. PBS Learning Media: Origins of Wave Energy

    NSDL National Science Digital Library

    2009-03-09

    This is a standards-aligned lesson plan for secondary education on the topic of mechanical wave motion. The lesson blends a six-minute video with a classroom activity that uses Slinky springs to model transverse and longitudinal waves. Explicit directions are given to support new or crossover teachers, including background information on wave energy and discussion questions. The resource was developed for use with the video "Making Big Waves", which may be freely downloaded for classroom use. Teachers' Domain, a network partner of the National Science Digital Library (NSDL), is a growing collection of free educational resources compiled by researchers and experienced teachers to promote the use of digital resources in the classroom.

  17. Progress in high power, high efficiency relativistic traveling wave tube amplifiers

    SciTech Connect

    Nation, J.A.; Naqvi, S.A.; Kerslick, G.S. [Laboratory of Plasma Studies School of Electrical Engineering, Cornell University, Ithaca, New York 14853 (United States); Schaechter, L. [Laboratory of Plasma Studies School of Electrical Engineering Cornell University, Ithaca, New York 14853 (United States of America)]|[Department of Electrical Engineering, Technion-Israel Institute of Technology, Haifa32000 (Israel)

    1997-03-01

    We present an overview of recent research at Cornell University on the use of relativistic traveling wave tube amplifiers for high power microwave generation. We consider three topics namely the dependence of the amplifier gain on the beam energy, axial energy extraction using a TM to TEM mode converter, and techniques for enhancing the efficiency of the amplifier to at least 50{percent}. {copyright} {ital 1997 American Institute of Physics.}

  18. Water Power for a Clean Energy Future (Fact Sheet)

    SciTech Connect

    Not Available

    2012-03-01

    This fact sheet provides an overview of the U.S. Department of Energy's Wind and Water Power Program's water power research activities. Water power is the nation's largest source of clean, domestic, renewable energy. Harnessing energy from rivers, manmade waterways, and oceans to generate electricity for the nation's homes and businesses can help secure America's energy future. Water power technologies fall into two broad categories: conventional hydropower and marine and hydrokinetic technologies. Conventional hydropower facilities include run-of-the-river, storage, and pumped storage. Most conventional hydropower plants use a diversion structure, such as a dam, to capture water's potential energy via a turbine for electricity generation. Marine and hydrokinetic technologies obtain energy from waves, tides, ocean currents, free-flowing rivers, streams and ocean thermal gradients to generate electricity. The United States has abundant water power resources, enough to meet a large portion of the nation's electricity demand. Conventional hydropower generated 257 million megawatt-hours (MWh) of electricity in 2010 and provides 6-7% of all electricity in the United States. According to preliminary estimates from the Electric Power Resource Institute (EPRI), the United States has additional water power resource potential of more than 85,000 megawatts (MW). This resource potential includes making efficiency upgrades to existing hydroelectric facilities, developing new low-impact facilities, and using abundant marine and hydrokinetic energy resources. EPRI research suggests that ocean wave and in-stream tidal energy production potential is equal to about 10% of present U.S. electricity consumption (about 400 terrawatt-hours per year). The greatest of these resources is wave energy, with the most potential in Hawaii, Alaska, and the Pacific Northwest. The Department of Energy's (DOE's) Water Power Program works with industry, universities, other federal agencies, and DOE's national laboratories to promote the development and deployment of technologies capable of generating environmentally sustainable and cost-effective electricity from the nation's water resources.

  19. Nonlinear Interaction of a Powerful Oblique Wave Beam with the Ionosphere Layer F2.

    NASA Astrophysics Data System (ADS)

    Atamaniuk, Barbara; Rothkaehl, Hanna; Anatolevich Molotkov, Ivan; Popov, Alexei

    2013-04-01

    The presentation is devoted to modeling oblique sounding of the ionosphere layer F2 by powerful wave beams. Part of its energy propagates trough the ionospheric layer, the other part goes back along a downward trajectory. However, nonlinearity leads to further stratification of the ionospheric layer. A new feature, in comparison with the linear case, is appearing a narrow waveguide beneath the F2 layer maximum which traps a small part of the beam energy. • We study the relationship between these parts of the wave field in a simplified model of parabolic F2 layer, with nonlinearity caused by thermal plasma expulsion from the high field intensity region. • We model and analyze of the interaction of a powerful obliquely incident wave beam of decameter radio waves with the ionospheric layer F2. Oblique propagation of a powerful HF wave beam in the ionospheric F2 layer leads to additional plasma stratification, in particular to the formation of an artificial waveguide controlled by the beam intensity. We show that formation of the artificial waveguide is a nonlinear effect. The problem of efficient feeding the artificial waveguide depends on the ability to create in the F2 layer high values of the HF electric field compared with the characteristic "plasma fields". Analytical results are supplemented with numerical estimates of the effects. The proposed investigation can be used in Space Weather Services.

  20. Field-aligned chorus wave spectral power in Earth's outer radiation belt

    NASA Astrophysics Data System (ADS)

    Breuillard, H.; Agapitov, O.; Artemyev, A.; Kronberg, E. A.; Haaland, S. E.; Daly, P. W.; Krasnoselskikh, V. V.; Boscher, D.; Bourdarie, S.; Zaliznyak, Y.; Rolland, G.

    2015-05-01

    Chorus-type whistler waves are one of the most intense electromagnetic waves generated naturally in the magnetosphere. These waves have a substantial impact on the radiation belt dynamics as they are thought to contribute to electron acceleration and losses into the ionosphere through resonant wave-particle interaction. Our study is devoted to the determination of chorus wave power distribution on frequency in a wide range of magnetic latitudes, from 0 to 40°. We use 10 years of magnetic and electric field wave power measured by STAFF-SA onboard Cluster spacecraft to model the initial (equatorial) chorus wave spectral power, as well as PEACE and RAPID measurements to model the properties of energetic electrons (~ 0.1-100 keV) in the outer radiation belt. The dependence of this distribution upon latitude obtained from Cluster STAFF-SA is then consistently reproduced along a certain L-shell range (4 ? L ? 6.5), employing WHAMP-based ray tracing simulations in hot plasma within a realistic inner magnetospheric model. We show here that, as latitude increases, the chorus peak frequency is globally shifted towards lower frequencies. Making use of our simulations, the peak frequency variations can be explained mostly in terms of wave damping and amplification, but also cross-L propagation. These results are in good agreement with previous studies of chorus wave spectral extent using data from different spacecraft (Cluster, POLAR and THEMIS). The chorus peak frequency variations are then employed to calculate the pitch angle and energy diffusion rates, resulting in more effective pitch angle electron scattering (electron lifetime is halved) but less effective acceleration. These peak frequency parameters can thus be used to improve the accuracy of diffusion coefficient calculations.

  1. Ground Detection of Gyro Resonant Plasma Waves During High Power Radio Waves Experiments at HAARP (Invited)

    NASA Astrophysics Data System (ADS)

    Bernhardt, P. A.; Pedersen, T. R.; Kendall, E. A.

    2010-12-01

    High power radio waves transmitted from the ground can enter the ionosphere and become transformed into electrostatic waves by mode coupling or parametric decay. The decay products may be electromagnetic (EM) waves that propagate to the ground and are detected by ground receivers. The decay products may also be electrostatic waves that are mode converted to EM waves for propagation to ground receivers. The EM signals have frequency offsets from the EM pump wave and are called stimulated electromagnetic emissions (SEE). The production of SEE requires five factors for excitation. First, the EM pump wave must have sufficient amplitude in the ionosphere to excite the parametric decay process. Second, the EM pump wave must propagate to a region where it can couple into a resonant mode of the plasma. Third, the large amplitude EM or ES resonant mode drives a parametric decay instability to generate two other resonant modes in the plasma. Fourth, at least one resonant mode in the plasma must be weakly damped. Fifth, the high frequency daughter wave of the parametric decay process may need to be converted into an electromagnetic wave to be received on the ground. In the framework of these five criteria, the production of stimulated ion Bernstein (SIB) emissions is considered for an electromagnetic pump wave tuned to the second harmonic of the electron cyclotron frequency. For maximum pump amplitude, the plasma frequency should be nearly equal to the pump frequency. This double resonance occurs if the EM pump frequency is tuned to match the frequency at the altitude where the plasma frequency in the plasma layer is equal to twice the electron gyro frequency. The double resonance of pump frequency equals plasma frequency equals twice the electron gyro frequency insures that a large amplitude standing wave is formed at the point where the pump electric field can couple into the electron Bernstein resonance at twice the electron cyclotron frequency. The theory for generation of electrostatic by the stimulated electron/ion Bernstein (SEIB) instability has been verified with ground observations of SEE at the HAARP facility in Alaska. The electron Bernstein wave can also decay into another electron Bernstein wave and a lower-hybrid wave. Decay products such as electron Bernstein waves can efficiently accelerate electrons in the ionosphere by cyclotron resonance. The SEE measurements compared with optical and electron density measurements show a strong correlation of Bernstein modes and electron acceleration.

  2. Exotic power and energy storage

    Microsoft Academic Search

    M. O. Surface

    1977-01-01

    Consideration is given to a variety of near-term energy storage systems, including both conventional and underground hydro-pumped storage, compressed air storage for combustion turbines, thermal energy storage in central power plants, and the lead-acid battery. Potential intermediate-term systems, which may be developed during the 1985-2000 period, are identified, such as advanced batteries, flywheel storage, and hydrogen storage. The concept of

  3. Modeling and enhancement of piezoelectric power extraction from one-dimensional bending waves

    NASA Astrophysics Data System (ADS)

    Tol, S.; Degertekin, F. L.; Erturk, A.

    2014-04-01

    Vibration-based energy harvesting has been heavily researched over the last decade to enable self-powered small electronic components for wireless applications in various disciplines ranging from biomedical to civil engineering. The existing research efforts in this interdisciplinary field have mostly focused on the harvesting of deterministic or stochastic vibrational energy available at a fixed position in space. Such an approach is convenient to design and employ linear and nonlinear vibration-based energy harvesters, such as base-excited cantilevers with piezoelectric laminates. However, persistent vibrations at a fixed frequency and spatial point, or standing wave patterns, are rather simplified representations of ambient vibrational energy. As an alternative to energy harvesting from spatially localized vibrations and standing wave patterns, this work presents an investigation into the harvesting of one-dimensional bending waves in infinite beams. The focus is placed on the use of piezoelectric patches bonded to a thin and long beam and employed to transform the incoming wave energy into usable electricity while minimizing the traveling waves reflected and transmitted from the harvester domain. To this end, performance enhancement by wavelength matching, resistiveinductive circuits, and a localized obstacle are explored. Electroelastic model predictions and performance enhancement efforts are validated experimentally for various case studies.

  4. Energy exchange and wave action conservation for magnetohydrodynamic (MHD) waves in a general, slowly varying medium

    NASA Astrophysics Data System (ADS)

    Walker, A. D. M.

    2014-12-01

    Magnetohydrodynamic (MHD) waves in the solar wind and magnetosphere are propagated in a medium whose velocity is comparable to or greater than the wave velocity and which varies in both space and time. In the approximation where the scales of the time and space variation are long compared with the period and wavelength, the ray-tracing equations can be generalized and then include an additional first-order differential equation that determines the variation of frequency. In such circumstances the wave can exchange energy with the background: wave energy is not conserved. In such processes the wave action theorem shows that the wave action, defined as the ratio of the wave energy to the frequency in the local rest frame, is conserved. In this paper we discuss ray-tracing techniques and the energy exchange relation for MHD waves. We then provide a unified account of how to deal with energy transport by MHD waves in non-uniform media. The wave action theorem is derived directly from the basic MHD equations for sound waves, transverse Alfvén waves, and the fast and slow magnetosonic waves. The techniques described are applied to a number of illustrative cases. These include a sound wave in a medium undergoing a uniform compression, an isotropic Alfvén wave in a steady-state shear layer, and a transverse Alfvén wave in a simple model of the magnetotail undergoing compression. In each case the nature and magnitude of the energy exchange between wave and background is found.

  5. An atlas of the wave energy resource in Europe

    SciTech Connect

    Pontes, M.T. [INETI-ITE, Lisbon (Portugal); Athanassoulis, G.A. [National Technical Univ., Athens (Greece); Barstow, S. [OCEANOR S.A., Trondheim (Norway); Cavaleri, L. [ISDGM, Venice (Italy); Holmes, B. [University Coll., Cork (Iran, Islamic Republic of); Mollison, D. [Heriot-Watt Univ., Edinburgh (United Kingdom); Oliveira-Pires, H. [Inst. de Meteorologia, Lisbon (Portugal)

    1995-12-31

    This paper presents an Atlas of the European offshore wave energy resource that is being developed within the scope of an European project. It will be mainly based on wave estimates produced by the numerical wind-wave model WAM that is in routine operation at the European Centre for Medium-Range Weather Forecasts, Reading, UK. This model was chosen after a preliminary verification of two models again buoy data for a one-year period. Wave measurements will be used for the Norwegian Sea and the North Sea. The Atlas will be produced as a user-friendly software package for MS-DOS microcomputers permitting fast retrieval of information as well as saving and printing of statistics and maps. The Atlas will include annual and seasonal statistics of significant wave height, mean and peak period, mean direction and wave power levels (global values as well as directional distributions). These data will be both presented as tables, graphs and as geographic maps.

  6. Wind power: Today's energy option

    Microsoft Academic Search

    2009-01-01

    The US has about 1,400 megawatts (MW) of installed wind turbine capacity on-line to utilities primarily in California and Hawaii. And according to a recent report by the Electric Power Research Institute (EPRI), the best of today's wind turbines are performing well. When located in sites with good wind resources, today's superior designs have energy costs of about 8 cents

  7. Wave Energy Converter Effects on Wave Fields: Evaluation of SNL-SWAN and Sensitivity Studies in Monterey Bay CA.

    SciTech Connect

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

    2014-09-01

    A modified version of an indust ry standard wave modeling tool was evaluated, optimized, and utilized to investigate model sensitivity to input parameters a nd wave energy converter ( WEC ) array deployment scenarios. Wave propagation was investigated d ownstream of the WECs to evaluate overall near - and far - field effects of WEC arrays. The sensitivity study illustrate d that wave direction and WEC device type we r e most sensitive to the variation in the model parameters examined in this study . Generally, the changes in wave height we re the primary alteration caused by the presence of a WEC array. Specifically, W EC device type and subsequently their size directly re sult ed in wave height variations; however, it is important to utilize ongoing laboratory studies and future field tests to determine the most appropriate power matrix values for a particular WEC device and configuration in order to improve modeling results .

  8. Fast wave power flow along SOL field lines in NSTX

    NASA Astrophysics Data System (ADS)

    Perkins, R. J.; Bell, R. E.; Diallo, A.; Gerhardt, S.; Hosea, J. C.; Jaworski, M. A.; Leblanc, B. P.; Kramer, G. J.; Phillips, C. K.; Roquemore, L.; Taylor, G.; Wilson, J. R.; Ahn, J.-W.; Gray, T. K.; Green, D. L.; McLean, A.; Maingi, R.; Ryan, P. M.; Jaeger, E. F.; Sabbagh, S.

    2012-10-01

    On NSTX, a major loss of high-harmonic fast wave (HHFW) power can occur along open field lines passing in front of the antenna over the width of the scrape-off layer (SOL). Up to 60% of the RF power can be lost and at least partially deposited in bright spirals on the divertor floor and ceiling [1,2]. The flow of HHFW power from the antenna region to the divertor is mostly aligned along the SOL magnetic field [3], which explains the pattern of heat deposition as measured with infrared (IR) cameras. By tracing field lines from the divertor back to the midplane, the IR data can be used to estimate the profile of HHFW power coupled to SOL field lines. We hypothesize that surface waves are being excited in the SOL, and these results should benchmark advanced simulations of the RF power deposition in the SOL (e.g., [4]). Minimizing this loss is critical optimal high-power long-pulse ICRF heating on ITER while guarding against excessive divertor erosion.[4pt] [1] J.C. Hosea et al., AIP Conf Proceedings 1187 (2009) 105. [0pt] [2] G. Taylor et al., Phys. Plasmas 17 (2010) 056114. [0pt] [3] R.J. Perkins et al., to appear in Phys. Rev. Lett. [0pt] [4] D.L. Green et al., Phys. Rev. Lett. 107 (2011) 145001.

  9. Spectral Cascade and Energy Dissipation in Kinetic Alfven Wave Turbulence

    E-print Network

    Lin, Zhihong

    Spectral Cascade and Energy Dissipation in Kinetic Alfv´en Wave Turbulence Xi Cheng, Zhihong Lin energy sources at large spatial scales. The energy of these non- linearly interacting Alfven waves. 2000). The wave-particle energy exchange rates of these channels depend on the spectral properties near

  10. Microseismic measurement of wave-energy delivery to a rocky coast

    NASA Astrophysics Data System (ADS)

    Adams, Peter N.; Anderson, Robert S.; Revenaugh, Justin

    2002-10-01

    Rocky coasts are attacked by waves that drive sea-cliff retreat and etch promontories and embayments into the coastline. Understanding the evolution of such coastlines requires knowledge of the energy supplied by waves, which should depend upon both the deep-water waves and the coastal bathymetry they cross. We employ microseismic measurements of the wave-induced shaking of sea cliffs near Santa Cruz, California, as a proxy for the temporal pattern of wave-energy delivery to the coast during much of the winter 2001 storm season. Visual inspection of the time series suggests that both deep-water wave heights and tide levels exert considerable control on the energy delivered. We test this concept quantitatively with two models in which synthetic time series of wave power at the coast are compared with the shaking data. In the first model, deep-water wave power is linearly scaled by a fitting parameter; because this model fails to account for the strong tidal signal, it fits poorly. In the second model, the wave transformation associated with shoaling and refraction diminishes the nearshore wave power, and dissipation associated with bottom drag and wave breaking is parameterized by exponential dependencies on two length scales; this model reduces the variance by 32% 45% and captures the essence of the full signal. Shoaling and refraction greatly modulate the wave power delivered to the coast. Energy dissipated by bottom drag across the shelf is relatively small; the dissipation length scale is many times the path length across the shelf. In contrast, much energy is dissipated in the surf zone; the tidal-dissipation depth scale is of the same order as the tidal range (1 2 m), which accounts for the strong dependence of the cliff shaking on the tide.

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

    SciTech Connect

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

    2012-10-15

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

  12. High Power HF Excitation of Low Frequency Stimulated Electrostatic Waves in the Ionospheric Plasma over HAARP

    Microsoft Academic Search

    Paul Bernhardt; Craig A. Selcher

    2010-01-01

    High Power electromagnetic (EM) waves transmitted from the HAARP facility in Alaska can excite low frequency electrostatic waves by several processes including (1) direct magnetized stimulated Brillouin scatter (MSBS) and (2) parametric decay of high frequency electrostatic waves into electron and ion Bernstein waves. Either an ion acoustic (IA) wave with a frequency less than the ion cyclotron frequency (fCI)

  13. A low-power wave union TDC implemented in FPGA

    SciTech Connect

    Wu, Jinyuan; /Fermilab; Shi, Yanchen; Zhu, Douglas; /Illinois Math. Sci. Acad.

    2011-10-01

    A low-power time-to-digital convertor (TDC) for an application inside a vacuum has been implemented based on the Wave Union TDC scheme in a low-cost field programmable gate array (FPGA) device. Bench top tests have shown that a time measurement resolution better than 30 ps (standard deviation of time differences between two channels) is achieved. Special firmware design practices are taken to reduce power consumption. The measurements indicate that with 32 channels fitting in the FPGA device, the power consumption on the FPGA core voltage is approximately 9.3 mW/channel and the total power consumption including both core and I/O banks is less than 27 mW/channel.

  14. Millimeter-wave spectral line radiation from a powerful explosion

    SciTech Connect

    Kotov, Yu. B. [Keldysh Institute of Applied Mathematics (Russian Federation); Popov, V. D.; Semenova, T. A.; Fedorov, V. F. [National Research Nuclear University Moscow Engineering Physics Institute (Russian Federation)

    2012-01-15

    Millimeter-wave spectral line radiation from a powerful air explosion accompanied by neutron, X-ray, and gamma emission is considered. It is shown that the main contribution to the line radiation in the frequency window of air near the wavelength of 2.3 mm is made by nitric oxide molecules. The set of kinetic equations for a partially ionized plasma near the explosion is solved by the Runge-Kutta method. It is shown that the density of nitrogen oxide molecules increases in time to a certain steady-state level. The spectral power of radiation in the NO lines is estimated.

  15. Wave energy transmission apparatus for high-temperature environments

    NASA Technical Reports Server (NTRS)

    Buckley, John D. (Inventor); Edwards, William C. (Inventor); Kelliher, Warren C. (Inventor); Carlberg, Ingrid A. (Inventor)

    2010-01-01

    A wave energy transmission apparatus has a conduit made from a refractory oxide. A transparent, refractory ceramic window is coupled to the conduit. Wave energy passing through the window enters the conduit.

  16. E2I EPRI Assessment Offshore Wave Energy Conversion Devices

    E-print Network

    E2I EPRI Assessment Offshore Wave Energy Conversion Devices Report: E2I EPRI WP ­ 004 ­ US ­ Rev 1 #12;E2I EPRI Assessment - Offshore Wave Energy Conversion Devices Table of Contents Introduction ............................................................................... 26 Appendix E - Orecon

  17. Deployment Effects of Marine Renewable Energy Technologies: Wave Energy Scenarios

    Microsoft Academic Search

    Mirko Previsic

    2010-01-01

    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

  18. ENergy and Power Evaluation Program

    SciTech Connect

    NONE

    1996-11-01

    In the late 1970s, national and international attention began to focus on energy issues. Efforts were initiated to design and test analytical tools that could be used to assist energy planners in evaluating energy systems, particularly in developing countries. In 1984, the United States Department of Energy (DOE) commissioned Argonne National Laboratory`s Decision and Information Sciences Division (DIS) to incorporate a set of analytical tools into a personal computer-based package for distribution in developing countries. The package developed by DIS staff, the ENergy and Power Evaluation Program (ENPEP), covers the range of issues that energy planners must face: economic development, energy demand projections, supply-and-demand balancing, energy system expansion, and environmental impact analysis. Following the original DOE-supported development effort, the International Atomic Energy Agency (IAEA), with the assistance from the US Department of State (DOS) and the US Department of Energy (DOE), provided ENPEP training, distribution, and technical support to many countries. ENPEP is now in use in over 60 countries and is an international standard for energy planning tools. More than 500 energy experts have been trained in the use of the entire ENPEP package or some of its modules during the international training courses organized by the IAEA in collaboration with Argonne`s Decision and Information Sciences (DIS) Division and the Division of Educational Programs (DEP). This report contains the ENPEP program which can be download from the internet. Described in this report is the description of ENPEP Program, news, forums, online support and contacts.

  19. Wave Turbulence in Superfluid 4 Energy Cascades, Rogue Waves & Kinetic Phenomena

    E-print Network

    Fominov, Yakov

    Outline Wave Turbulence in Superfluid 4 He: Energy Cascades, Rogue Waves & Kinetic Phenomena Conference, Chernogolovka, 3 August 2009 McClintock Efimov Ganshin Kolmakov Mezhov-Deglin Wave Turbulence in Superfluid 4 He #12;Outline Outline 1 Introduction Motivation 2 Modelling wave turbulence Need for models

  20. Ecological Effects of Wave Energy Development in the Pacific Northwest

    E-print Network

    Ecological Effects of Wave Energy Development in the Pacific Northwest A Scientific Workshop Technical Memorandum NMFS-F/SPO-92 #12;#12;Ecological Effects of Wave Energy Development in the Pacific Service; Justin Klure, Oregon Wave Energy Trust; Greg McMurray, Oregon Department of Land Conservation

  1. Energy velocity and quality factor of poroelastic waves in isotropic media.

    PubMed

    Gerasik, Vladimir; Stastna, Marek

    2011-05-01

    The energy velocity and Q factor of poroelastic acoustic waves in the context of classical isotropic Biot's theory are revisited. Special attention is paid to the high frequency regime when interphase interaction is viscoelastic. The analogy with viscoelastic behavior is emphasized in derivation of the energy balance equations which relate kinetic energy, potential energy, viscous power dissipation, and elastic energy stored associated with each wave. These lead to exact closed form expressions for the energy velocity and Q factor for both longitudinal and shear waves from energy principles. Most notably, the analysis of the resulting expressions reveals that the energy velocity of both longitudinal and shear waves equals (exceeds) the corresponding phase velocity in the case of the low (full) frequency range theory, and that the exact expression for the Q factor contains an additive correction due to viscoelastic interphase interaction. PMID:21568384

  2. Towards a Predictive Model of Power Loss from Parametric Decay of ICRF Waves

    SciTech Connect

    Myra, J. R. [Lodestar Research Corporation, Boulder, Colorado (United States); Berry, L. A.; Jaeger, E. F. [Oak Ridge National Laboratory, Oak Ridge, Tennessee (United States)

    2007-09-28

    Both theory and experiment have suggested that parametric decay instability (PDI) is a possible edge power loss mechanism in ICRF (including HHFW and IBW) heating of tokamak plasmas. In this paper, we consider the extension of previous theoretical models to enable a quantitative evaluation of pump depletion and power loss due to PDI. A set of nonlinear coupled equations for a long-wavelength 'dipole' pump and short-wavelength daughter modes is derived. The model recovers the standard PDI dispersion relation for fixed pump wave amplitude, and obeys an appropriate nonlinear energy conservation law. When dissipation is present the model provides a description of energy flow from the pump to the daughter modes and the particles. The equations are intended to describe parametric decay and pump depletion in inhomogeneous plasmas. By writing the nonlinear coupling coefficients in terms of a spectral basis, a strategy for implementing the model in full-wave spectral codes is presented.

  3. PIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY

    E-print Network

    Ervin, Elizabeth K.

    with other smart materials for power harvesting #12;Piezoelectric MaterialsPiezoelectric MaterialsPIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY PIEZOELECTRIC POWER SCAVENGING and magneticand magnetic field.field. Piezoelectric Materials as Smart Material- Among the all smart materials

  4. Reference Model 5 (RM5): Oscillating Surge Wave Energy Converter

    SciTech Connect

    Yu, Y. H.; Jenne, D. S.; Thresher, R.; Copping, A.; Geerlofs, S.; Hanna, L. A.

    2015-01-01

    This report is an addendum to SAND2013-9040: Methodology for Design and Economic Analysis of Marine Energy Conversion (MEC) Technologies. This report describes an Oscillating Water Column Wave Energy Converter (OSWEC) reference model design in a complementary manner to Reference Models 1-4 contained in the above report. A conceptual design for a taut moored oscillating surge wave energy converter was developed. The design had an annual electrical power of 108 kilowatts (kW), rated power of 360 kW, and intended deployment at water depths between 50 m and 100 m. The study includes structural analysis, power output estimation, a hydraulic power conversion chain system, and mooring designs. The results were used to estimate device capital cost and annual operation and maintenance costs. The device performance and costs were used for the economic analysis, following the methodology presented in SAND2013-9040 that included costs for designing, manufacturing, deploying, and operating commercial-scale MEC arrays up to 100 devices. The levelized cost of energy estimated for the Reference Model 5 OSWEC, presented in this report, was for a single device and arrays of 10, 50, and 100 units, and it enabled the economic analysis to account for cost reductions associated with economies of scale. The baseline commercial levelized cost of energy estimate for the Reference Model 5 device in an array comprised of 10 units is $1.44/kilowatt-hour (kWh), and the value drops to approximately $0.69/kWh for an array of 100 units.

  5. Flow Characteristics in an Augmentation Channel of a Direct Drive Turbine for Wave Power Generation

    NASA Astrophysics Data System (ADS)

    Prasad, Deepak; Zullah, Mohammed Asid; Choi, Young-Do; Lee, Young-Ho

    2010-06-01

    Cross flow turbine also known as Banki turbine, is a hydraulic turbine that may be classified as an impulse turbine. At present it has gained interest in small and low head establishments because of its simple structure, cost effectiveness and low maintenance. Therefore, the present paper expands on this idea and aims at implementing the Direct Drive Turbine (DDT) for wave power generation. Wave power has enormous amount of energy which is environmentally friendly, renewable and can be exploited to satisfy the energy needs. A Numerical Wave Tank (NWT) was used to simulate the sea conditions and after obtaining desired wave properties; the augmentation channel plus the front guide nozzle and rear chamber were integrated to the NWT. The augmentation channel consisted of a front nozzle, rear nozzle and an internal fluid region which represented the turbine housing. The front and rear nozzle were geometrically identical. Two different nozzle configurations were studied; spiral rear wall type and a straight rear wall type. In addition to this, the effect of front guide nozzle divergent angle was also studied. The general idea is to investigate how different augmentation channel geometry and front guide nozzle divergent angle affects the flow, the water horse power and the first stage (primary stage) energy conversion. The analysis was performed using a commercial CFD code of the ANSYS-CFX. The results of the flow in an augmentation channel of the Direct Drive Turbine in oscillating flow for all the cases are presented by means of pressure and velocity vectors. The water horse power (WHP) and first stage energy conversion for the models are also presented.

  6. Control strategies to optimise power output in heave buoy energy convertors

    NASA Astrophysics Data System (ADS)

    Abu Zarim, M. A. U. A.; Sharip, R. M.

    2013-12-01

    Wave energy converter (WEC) designs are always discussed in order to obtain an optimum design to generate the power from the wave. Output power from wave energy converter can be improved by controlling the oscillation in order to acquire the interaction between the WEC and the incident wave.The purpose of this research is to study the heave buoys in the interest to generate an optimum power output by optimising the phase control and amplitude in order to maximise the active power. In line with the real aims of this study which investigate the theory and function and hence optimise the power generation of heave buoys as renewable energy sources, the condition that influence the heave buoy must be understand in which to propose the control strategies that can be use to control parameters to obtain optimum power output. However, this research is in an early stage, and further analysis and technical development is require.

  7. 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-resolution (fine scale, very near-field) fluid/structure interaction simulations of buoy motions, as well as array-scale, phase-resolving wave scattering simulations. These modeling efforts will utilize state-of-the-art research quality models, which have not yet been brought to bear on this complex problem of large array wave/structure interaction problem.

  8. High-Power, High-Efficiency Ka-Band Space Traveling-Wave Tube

    NASA Technical Reports Server (NTRS)

    Krawczyk, Richard; Wilson, Jeffrey; Simons, Rainee; Williams, Wallace; Bhasin, Kul; Robbins, Neal; Dibb, Daniel; Menninger, William; Zhai, Xiaoling; Benton, Robert; Burdette, James

    2007-01-01

    The L-3 Communications Model 999H traveling-wave tube (TWT) has been demonstrated to generate an output power of 144 W at 60-percent overall efficiency in continuous-wave operation over the frequency band from 31.8 to 32.3 GHz. The best TWT heretofore commercially available for operation in the affected frequency band is characterized by an output power of only 35 W and an efficiency of 50 percent. Moreover, whereas prior TWTs are limited to single output power levels, it has been shown that the output power of the Model 999H can be varied from 54 to 144 W. A TWT is a vacuum electronic device used to amplify microwave signals. TWTs are typically used in free-space communication systems because they are capable of operating at power and efficiency levels significantly higher than those of solid-state devices. In a TWT, an electron beam is generated by an electron gun consisting of a cathode, focusing electrodes, and an anode. The electrons pass through a hole in the anode and are focused into a cylindrical beam by a stack of periodic permanent magnets and travel along the axis of an electrically conductive helix, along which propagates an electromagnetic wave that has been launched by an input signal that is to be amplified. The beam travels within the helix at a velocity close to the phase velocity of the electromagnetic wave. The electromagnetic field decelerates some of the electrons and accelerates others, causing the beam to become formed into electron bunches, which further interact with the electromagnetic wave in such a manner as to surrender kinetic energy to the wave, thereby amplifying the wave. The net result is to amplify the input signal by a factor of about 100,000. After the electrons have passed along the helix, they impinge on electrodes in a collector. The collector decelerates the electrons in such a manner as to recover most of the remaining kinetic energy and thereby significantly increase the power efficiency of the TWT.

  9. Power combiner

    DOEpatents

    Arnold, Mobius; Ives, Robert Lawrence

    2006-09-05

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

  10. Numerical implementation and sensitivity analysis of a wave energy converter in a time-dependent mild-slope equation model

    Microsoft Academic Search

    Charlotte Beels; Peter Troch; Griet De Backer; Marc Vantorre; Julien De Rouck

    2010-01-01

    Several Wave Energy Converters (abbreviated as WECs) have intensively been studied and developed during the last decade and currently small farms of WECs are getting installed. WECs in a farm are partly absorbing, partly redistributing the incident wave power. Consequently, the power absorption of each individual WEC in a farm is affected by its neighbouring WECs. The knowledge of the

  11. Open cycle traveling wave thermoacoustics: Energy fluxes and thermodynamics

    NASA Astrophysics Data System (ADS)

    Weiland, Nathan T.; Zinn, Ben T.

    2004-09-01

    In an open cycle traveling wave thermoacoustic engine, hot gas steadily flows into the hot side of the regenerator, replacing the hot heat exchanger as the primary energy source for the engine. In such an engine, interactions between the acoustic, convective, conductive and thermoacoustic energy fluxes facilitate conversion of the input thermal energy into acoustic energy. This study describes the energy flux interactions throughout the engine, thus clarifying the important role of the mean temperature difference that exists between the mean flow of hot gas and the hot-side regenerator interface in the open cycle engine. Furthermore, this study derives an optimal regenerator interface temperature that maximizes the acoustic power output of the engine for a given thermal energy input. The acoustic power output and thermal efficiency of the open cycle engine are compared to those in a closed cycle engine in which a crossflow heat exchanger is used to supply the required heat input. By accounting for the effectiveness of the heat exchanger, it is shown that the open cycle has the potential to achieve higher efficiencies than the closed cycle in converting the thermal energy in a stream of gas into acoustic energy.

  12. High power continuous wave injection-locked solid state laser

    SciTech Connect

    Nabors, C.D.; Byer, R.L.

    1991-06-25

    This patent describes an injection locked laser system. It comprises a master laser, the master laser including a solid state gain medium and having a continuous wave, single frequency output; a slave laser including a solid state gain medium located in a resonant cavity and having a continuous wave output at a power at least ten times greater than the master laser, with the output of the master laser being injected into the slave laser in order to cause the slave laser to oscillate at the same frequency as the output of the master laser; and means for actively stabilizing the slave laser so that its output frequency remains locked with the output frequency of the master laser.

  13. Tight-moored amplitude-limited heaving-buoy wave-energy converter with phase control

    Microsoft Academic Search

    H. Eidsmoen

    1998-01-01

    A time-domain mathematical model has been developed for a tight-moored heaving-buoy wave-energy converter, with a high-pressure hydraulic machinery for energy production and motion control. For comparison, a quite similar hydraulic machinery, without active control, has also been investigated.A procedure is developed for control in irregular waves, and, on the basis of a scatter table, the year-average power production of the

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

    E-print Network

    Texas at Austin. University of

    AIP/123-QED Experimental determination of radiated internal wave power without pressure field data-dimensional internal gravity waves. Both J and P are determined from expressions involving only a scalar function of a stratified fluid past a knife edge. The results for the radiated internal wave power given by the stream

  15. Estimating Internal Wave Energy Fluxes in the Ocean

    Microsoft Academic Search

    Jonathan D. Nash; Matthew H. Alford; Eric Kunze

    2005-01-01

    Energy flux is a fundamental quantity for understanding internal wave generation, propagation, and dissipation. In this paper, the estimation of internal wave energy fluxes up from ocean observations that may be sparse in either time or depth are considered. Sampling must be sufficient in depth to allow for the estimation of the internal wave-induced pressure anomaly p using the hydrostatic

  16. 78 FR 40132 - Wave Energy Converter Prize Administration Webinar

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-03

    ...Converter (WEC) devices in a wave tank test. The WWTPO anticipates...implementation of a prize challenge for wave energy converters. The information...this notice will be used for internal DOE planning including the potential...involved in the development of wave energy converters, (2)...

  17. Low-power continuous-wave nonlinear optics in doped silica glass integrated waveguide structures

    NASA Astrophysics Data System (ADS)

    Ferrera, M.; Razzari, L.; Duchesne, D.; Morandotti, R.; Yang, Z.; Liscidini, M.; Sipe, J. E.; Chu, S.; Little, B. E.; Moss, D. J.

    2008-12-01

    Photonic integrated circuits are a key component of future telecommunication networks, where demands for greater bandwidth, network flexibility, and low energy consumption and cost must all be met. The quest for all-optical components has naturally targeted materials with extremely large nonlinearity, including chalcogenide glasses and semiconductors, such as silicon and AlGaAs (ref. 4). However, issues such as immature fabrication technology for chalcogenide glass and high linear and nonlinear losses for semiconductors motivate the search for other materials. Here we present the first demonstration of nonlinear optics in integrated silica-based glass waveguides using continuous-wave light. We demonstrate four-wave mixing, with low (5 mW) continuous-wave pump power at ? = 1,550 nm, in high-index, doped silica glass ring resonators. The low loss, design flexibility and manufacturability of our device are important attributes for low-cost, high-performance, nonlinear all-optical photonic integrated circuits.

  18. 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 78712–1192 (United States)] [Physics Department and Institute for Fusion Studies, The University of Texas at Austin, Austin, Texas 78712–1192 (United States); Paoletti, M. S.; Swinney, Harry L. [Physics Department, The University of Texas at Austin, Austin, Texas 78712–1192 (United States)] [Physics Department, The University of Texas at Austin, Austin, Texas 78712–1192 (United States)

    2014-04-15

    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.

  19. Millimeter-Wave Wireless Power Transfer Technology for Space Applications

    NASA Technical Reports Server (NTRS)

    Chattopadhyay, Goutam; Manohara, Harish; Mojarradi, Mohammad M.; Vo, Tuan A.; Mojarradi, Hadi; Bae, Sam Y.; Marzwell, Neville

    2008-01-01

    In this paper we present a new compact, scalable, and low cost technology for efficient receiving of power using RF waves at 94 GHz. This technology employs a highly innovative array of slot antennas that is integrated on substrate composed of gold (Au), silicon (Si), and silicon dioxide (SiO2) layers. The length of the slots and spacing between them are optimized for a highly efficient beam through a 3-D electromagnetic simulation process. Antenna simulation results shows a good beam profile with very low side lobe levels and better than 93% antenna efficiency.

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

    SciTech Connect

    Paul T. Jacobson; George Hagerman; George Scott

    2011-12-01

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

  1. Internal energy relaxation in shock wave structure

    SciTech Connect

    Josyula, Eswar, E-mail: Eswar.Josyula@us.af.mil; Suchyta, Casimir J. [Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States)] [Air Force Research Laboratory, Wright-Patterson AFB, Ohio 45433 (United States); Boyd, Iain D. [University of Michigan, Ann Arbor, Michigan 48109 (United States)] [University of Michigan, Ann Arbor, Michigan 48109 (United States); Vedula, Prakash [University of Oklahoma, Norman, Oklahoma 73019 (United States)] [University of Oklahoma, Norman, Oklahoma 73019 (United States)

    2013-12-15

    The Wang Chang-Uhlenbeck (WCU) equation is numerically integrated to characterize the internal structure of Mach 3 and Mach 5 shock waves in a gas with excitation in the internal energy states for the treatment of inelastic collisions. Elastic collisions are modeled with the hard sphere collision model and the transition rates for the inelastic collisions modified appropriately using probabilities based on relative velocities of the colliding particles. The collision integral is evaluated by the conservative discrete ordinate method [F. Tcheremissine, “Solution of the Boltzmann kinetic equation for high-speed flows,” Comput. Math. Math. Phys. 46, 315–329 (2006); F. Cheremisin, “Solution of the Wang Chang-Uhlenbeck equation,” Dokl. Phys. 47, 487–490 (2002)] developed for the Boltzmann equation. For the treatment of the diatomic molecules, the internal energy modes in the Boltzmann equation are described quantum mechanically given by the WCU equation. As a first step in the treatment of the inelastic collisions by the WCU equation, a two- and three-quantum system is considered to study the effect of the varying of (1) the inelastic cross section and (2) the energy gap between the quantum energy states. An alternative method, the direct simulation Monte Carlo method, is used for the Mach 3 shock wave to ensure the consistency of implementation in the two methods and there is an excellent agreement between the two methods. The results from the WCU implementation showed consistent trends for the Mach 3 and Mach5 standing shock waves simulations. Inelastic contributions change the downstream equilibrium state and allow the flow to transition to the equilibrium state further upstream.

  2. Microchannel cooling of traveling-wave-tube circuit for ultrawideband high-power submillimeter-wave generation

    Microsoft Academic Search

    Yanbao Ma; Avijit Bhunia; Mark Field; Chung-Lung Chen

    2010-01-01

    High heat dissipation is generated in Traveling-wave-tube circuit for ultrawideband high-power submillimeter-wave generation due to e-beam power loss during transport. Active cooling is required to ensure the device can physically handle the high heat flux without damage. An efficient thermal management solution is provided for cooling the high-power vacuum device based on microchannel technology. A thermal conduction model is developed

  3. Temporal growth rate study of a high power backward wave oscillator with semi-circularly corrugated slow wave structure

    NASA Astrophysics Data System (ADS)

    Ghulam Saber, Md.; Hasan Sagor, Rakibul; Ruhul Amin, Md.

    2015-05-01

    The dispersion properties and the temporal growth rate (TGR) of a high power backward wave oscillator (BWO) with a cylindrical metallic slow wave structure with semi-circular corrugation (SCCSWS) driven by an intense relativistic electron beam (IREB) are studied numerically. The IREB is assumed to be guided axially by an infinitely strong magnetic field. The semi-circular axial profile of the SWS is approximated by Fourier series and the study is carried out utilizing linear Rayleigh-Fourier (R-F) theory. The Fourier constants of the axial profile are determined numerically. The dispersion equation is solved numerically for the beam energy of 80-660 kV, beam current of 0.1-1.0 kA. When an electron beam with sufficient energy and current to produce instability propagates through the SWS, microwave radiation is generated. TGR which is obtained from the imaginary value of frequency and wavenumber can be used to qualitatively estimate the strength of the microwave radiation. The periodicity of the axial profile of SCCSWS is varied and the TGR for each case has been calculated by varying the beam parameters for TM01 mode. The proposed structure is comparatively easy to be fabricated and expected to be useful in BWO devices for generating high power microwaves for different applications.

  4. Wave Energy Conversion Overview and it's Renewable Energy Potential for the Oil and Gas Industry

    E-print Network

    Pastor, J.; Liu, Y.; Dou, Y.

    2014-01-01

    . Keywords: hydrokinetic energy; wave energy; ocean energy; Gulf of Mexico; wave energy conversion INTRODUCTION Ocean energy comes in a variety of forms such as marine currents, tidal currents, geothermal vents, and waves. All are concentrated... currents and waves. Some research has been conducted on constructing a heat cycle based on geothermal vents, but this work has led to the conclusion that geothermal vents are not commercially viable [2]. On the other hand, ocean current and wave...

  5. Waves

    NSDL National Science Digital Library

    Mr. Hansen

    2010-11-12

    The following websites are useful tools in understanding how energy is transferred from place to place through waves. Start by downloading the assignment and then begin with website number 1 and continue until you have visited all three websites. Begin by downloading the IA Waves Internet Assignment: IA Waves Internet Assignment You will answer the questions in Microsoft Word and then e-mail the assignment to me. Website #1: Read about basic information on waves and answer the questions from part 1 of the IA Waves Guide: Basic Wave Information Website #2: Follow the instructions for the following ...

  6. New power meter concept for high energy lasers. Memorandum report

    SciTech Connect

    Ulrich, P.B.; Trusty, G.L.; Leslie, D.H.

    1981-09-24

    We describe a new concept for measurement of High Energy Laser (HEL) power. The technique is based upon the phenomenon of optoacoustic detection, which is a sensitive measurement of the sound waves created by absorption of a laser beam of known power with a sample of absorber material for the purpose of absorption coefficient determination. We propose that his process can be inverted to produce an absolute measurement of laser power by using a material for which the absorption coefficient at the laser frequency is sufficiently well known. We present a conceptual design and suggest studies for future development of the concept.

  7. Nanolithography with metastable helium atoms in a high-power standing-wave light field

    E-print Network

    Petra, S J H; Hogervorst, W; Vassen, W

    2004-01-01

    We have created periodic nanoscale structures in a gold substrate with a lithography process using metastable triplet helium atoms that damage a hydrofobic resist layer on top of the substrate. A beam of metastable helium atoms is transversely cooled and guided through an intense standing-wave light field. Compared to commonly used low-power optical masks, a high-power light field (saturation parameter of 10E7) increases the confinement of the atoms in the standing-wave considerably, and makes the alignment of the experimental setup less critical. Due to the high internal energy of the metastable helium atoms (20 eV), a dose of only one atom per resist molecule is required. With an exposure time of only eight minutes, parallel lines with a separation of 542 nm and a width of 100 nm (1/11th of the wavelength used for the optical mask) are created.

  8. Speech articulator measurements using low power EM-wave sensors

    SciTech Connect

    Holzrichter, J.F.; Burnett, G.C.; Ng, L.C. [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States)] [Lawrence Livermore National Laboratory, P.O. Box 808, Livermore, California 94551 (United States); Lea, W.A. [Speech Science Institute, P.O. Box 240428, Apple Valley, Minnesota 55124 (United States)] [Speech Science Institute, P.O. Box 240428, Apple Valley, Minnesota 55124 (United States)

    1998-01-01

    Very low power electromagnetic (EM) wave sensors are being used to measure speech articulator motions as speech is produced. Glottal tissue oscillations, jaw, tongue, soft palate, and other organs have been measured. Previously, microwave imaging (e.g., using radar sensors) appears not to have been considered for such monitoring. Glottal tissue movements detected by radar sensors correlate well with those obtained by established laboratory techniques, and have been used to estimate a voiced excitation function for speech processing applications. The noninvasive access, coupled with the small size, low power, and high resolution of these new sensors, permit promising research and development applications in speech production, communication disorders, speech recognition and related topics. {copyright} {ital 1998 Acoustical Society of America.}

  9. Ulysses observations of magnetic waves due to newborn interstellar pickup ions. II. Application of turbulence concepts to limiting wave energy and observability

    SciTech Connect

    Cannon, Bradford E. [Physics Department, Florida State University, Tallahassee, FL 32306 (United States); Smith, Charles W.; Isenberg, Philip A.; Vasquez, Bernard J.; Joyce, Colin J. [Physics Department and Space Science Center, Institute for the Study of Earth, Oceans, and Space, University of New Hampshire, Durham, NH 03824 (United States); Murphy, Neil [Jet Propulsion Laboratory, Mail Stop 180-600, 4800 Oak Grove Drive, Pasadena, CA 91109 (United States); Nuno, Raquel G., E-mail: bc13h@my.fsu.edu, E-mail: Charles.Smith@unh.edu, E-mail: Phil.Isenberg@unh.edu, E-mail: Bernie.Vasquez@unh.edu, E-mail: cjl46@wildcats.unh.edu, E-mail: Neil.Murphy@jpl.nasa.gov, E-mail: raquel.nuno@asu.edu [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States)

    2014-06-01

    The low-frequency magnetic waves that arise from the isotropization of newborn interstellar pickup ions (PUIs) are reasonably well described by linear and quasi-linear kinetic theory in so far as those theories predict the wave frequency and polarization in the spacecraft frame. Those theories fail to describe the scarce observability of the waves. Quasilinear theory predicts that the wave power should accumulate over long periods of time as the relatively weak kinetic instability slowly adds power to the observed spectrum. At the same time it has been argued that the same wave energy must serve as a secondary source of thermal ion heating in the outer heliosphere once the initial turbulence is depleted. To the extent that turbulent transport of the wave energy acts against the spectrally confined accumulation of wave energy, turbulence should be a limiting factor in observability. We argue that turbulence does limit the observability of the waves and we use turbulence theory to predict the observed wave energy. We compare this prediction against a database of 502 wave observations attributed to newborn interstellar PUIs observed by the Ulysses spacecraft.

  10. An atlas of the wave-energy resource in Europe

    SciTech Connect

    Pontes, M.T. [INETI-ITE, Lisbon (Portugal); Athanassoulis, G.A. [NTUA, Athens (Greece); Barstow, S. [OCEANOR A/S, Trondheim (Norway); Cavaleri, L. [ISDGM, Venice (Italy); Holmes, B. [UCC, Cork (Ireland); Mollison, D. [HWU, Edinburgh (United Kingdom); Oliveira-Pires, H. [IM, Lisbon (Portugal)

    1996-11-01

    An atlas of the European offshore wave energy resource, being developed within the scope of a European R and D program, includes the characterization of the offshore resource for the Atlantic and Mediterranean coasts of Europe in addition to providing wave-energy and wave-climate statistics that are of interest to other users of the ocean. The wave data used for compiling the Atlas came from the numerical wind-wave model WAM, implemented in the routine operation of the European Centre for Medium Range Weather Forecasts (ECMWF), in addition to directional wave measurements from the Norwegian offshore waters.

  11. Alternative Energy and Remote Power Products

    NSDL National Science Digital Library

    Based in Alaska, ABS Alaskan provides batteries, alternative energy and remote and power products. The site contains a Library link, where users can explore a basic power system diagram, visit the document download center, and find information explaining alternative energy and power systems.

  12. Energy harvesting from a standing wave thermoacoustic-piezoelectric resonator

    NASA Astrophysics Data System (ADS)

    Smoker, J.; Nouh, M.; Aldraihem, O.; Baz, A.

    2012-05-01

    In this paper, a one-dimensional thermoacoustic-piezoelectric (TAP) resonator is developed to convert thermal energy, such as solar or waste heat energy, directly into electrical energy. The thermal energy is utilized to generate a steep temperature gradient along a porous stack which is optimally sized and placed near one end of the resonator. At a specific threshold of the temperature gradient, self-sustained acoustic waves are generated inside the resonator. The resulting pressure fluctuations excite a piezoelectric diaphragm, placed at the opposite end of the resonator, which converts the acoustic energy directly into electrical energy without the need for any moving components. The theoretical performance characteristics of this class of thermoacoustic-piezoelectric resonators are predicted using the Design Environment for Low-amplitude Thermoacoustic Energy Conversion Software. These characteristics are validated experimentally on a small prototype of the system. Particular emphasis is placed on monitoring the temperature field using infrared camera, the flow field using particle image velocimetry, the acoustic field using an array of microphones, and the energy conversion efficiency. Comparisons between the theoretical predictions and the experimental results are also presented. The developed theoretical and experimental techniques can be invaluable tools in the design of TAP resonators for harvesting thermal energy in areas far from the power grid such as nomadic communities and desert regions for light, agricultural, air conditioning, and communication applications.

  13. Energy emission from evanescent wave and interference of opposite wave streams

    NASA Astrophysics Data System (ADS)

    Barabanenkov, M. Yu.; Barabanenkov, Yu. N.; Gulyaev, Yu. V.; Nikitov, S. A.

    2007-05-01

    A basic formula for the coefficient of energy emission from an evanescent electromagnetic wave at scattering by a dielectric structure is derived. The derived formula is interpreted in terms of interference of an incident evanescent wave with its reflection by the structure and applied to evanescent wave scattering by a 3D random medium.

  14. High power HF modification: Geophysics, span of EM effects, and energy budget

    Microsoft Academic Search

    Herbert C. Carlson

    1993-01-01

    As the electric field and power density of radio wave (RF) radiation increases continuously in a plasma, the response of the plasma to the incident energy changes discontinuously. This follows from a complex set of competing processes, each generally with its own power dependent threshold, and plasma instabilities, each with their own growth and decay rate. Non-linear power dependencies, and

  15. Wave refraction and wave energy on Cayo Arenas 

    E-print Network

    Walsh, Donald Eugene

    1962-01-01

    to obtain proper resolution up to the breaker zone. This segmentation ordinarily is required where a deep indentation or a sharp projection in a depth contour occurs so that the full width of wave ray sps. cmg cannot be considered as a single unit. Onc..., General Wave Theory, [ 1], [14], [16], [ 52], [53], [54], [55], [64], [66], [67], [72]; Refraction, [3], [4], [5], [19], [31], [51]; Oscillatory Wave Theory, [8], [9], [10], [?], l?], [?], [ 201, [22], [3O], [4o], [42], [46], [47], [491, [5o1, [53...

  16. INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME

    E-print Network

    . The mission of the Photovoltaic Power Systems Programme is ,,to enhance the international collaboration obtained by weather forecast models. Digital atlases have been created as integrated information system#12;INTERNATIONAL ENERGY AGENCY PHOTOVOLTAIC POWER SYSTEMS PROGRAMME TASK 2 ­ Performance

  17. Networks of triboelectric nanogenerators for harvesting water wave energy: a potential approach toward blue energy.

    PubMed

    Chen, Jun; Yang, Jin; Li, Zhaoling; Fan, Xing; Zi, Yunlong; Jing, Qingshen; Guo, Hengyu; Wen, Zhen; Pradel, Ken C; Niu, Simiao; Wang, Zhong Lin

    2015-03-24

    With 70% of the earth's surface covered with water, wave energy is abundant and has the potential to be one of the most environmentally benign forms of electric energy. However, owing to lack of effective technology, water wave energy harvesting is almost unexplored as an energy source. Here, we report a network design made of triboelectric nanogenerators (TENGs) for large-scale harvesting of kinetic water energy. Relying on surface charging effect between the conventional polymers and very thin layer of metal as electrodes for each TENG, the TENG networks (TENG-NW) that naturally float on the water surface convert the slow, random, and high-force oscillatory wave energy into electricity. On the basis of the measured output of a single TENG, the TENG-NW is expected to give an average power output of 1.15 MW from 1 km(2) surface area. Given the compelling features, such as being lightweight, extremely cost-effective, environmentally friendly, easily implemented, and capable of floating on the water surface, the TENG-NW renders an innovative and effective approach toward large-scale blue energy harvesting from the ocean. PMID:25719956

  18. Mechanism for generating power from wave motion on a body of water

    SciTech Connect

    Sachs, G.A.; Sachs, H.K.

    1982-09-28

    A mechanism for generating power from wave motion on a body of water is described. The mechanism includes a buoyant body which is adapted to float on a body of water and to roll and pitch in response to the wave motion of the water. A gyro-wave energy transducer is mounted on the buoyant body for translating the pendulum-like motions of the buoyant body into rotational motion. The gyro-wave energy transducer includes a gimbal comprised of first and second frames, with the first frame being pivotally mounted to the second frame and the second frame being pivotally mounted to the buoyant body. A gyroscope is mounted to the first frame for rotation about an axis perpendicular to the axes of rotation of the first and second frames. A motor/generator is coupled to the gyroscope for maintaining a controlled rotational velocity for the gyroscope. Transferring members are associated with one of the first and second frames for transferring torque of one of the first and second frames to the gyroscope about an axis that is perpendicular to that of the gyroscope which results in rotation of the other of the first and second frames. An electrical generator is responsive to the relative rotational movement of the first and second frames for generating electrical energy. A storage battery is mounted on the buoyant body for storing and releasing electrical energy and is operatively coupled to the motor/generator and the electrical generator. A control circuit is associated with the generator and the motor/generator unit of the gyroscope and is responsive to the time rate of change of current produced by the generator for controlling the rotational velocity of the gyroscope in order to maintain maximum power output from the electrical generator.

  19. Real-time Ocean Wave Prediction for Optimal Performance of a Wave Energy Converter

    NASA Astrophysics Data System (ADS)

    Cavaglieri, Daniele; Bewley, Thomas

    2013-11-01

    In recent years, there has been a growing interest in renewable energy. Among all the available possibilities, wave energy conversion, due to the huge availability of energy that the ocean could provide, represents nowadays one of the most promising solutions. However, the efficiency of a wave energy converter for ocean wave energy harvesting is still far from making it competitive with more mature fields of renewable energy, such as solar and wind energy. One of the main problems is related to the inability to accurately predict the profile of oncoming waves approaching the wave energy converter. For this reason, we developed a new hybrid method for state estimation of nonlinear systems, which is based on a variational formulation of an ensemble smoother, combined with the formulation of the ensemble Kalman smoother. This method has been employed for the optimal forecasting of ocean waves via sensors placed on an array of wave energy converters. The coupled simulation of ocean waves and energy devices has been carried out leveraging a nonlinear High Order Spectral code.

  20. The dynamics of Wave Carpet - a novel deep water wave energy design

    Microsoft Academic Search

    Paul Mario Koola; A. Ibragimov

    2003-01-01

    Wave Carpet is a novel deep offshore wave-power floating system concept funded by the Office of Naval Research that will have low overall life cycle cost due to an integrated design and be rapidly re-deployable. In this paper we numerically model the Wave Carpet motion using a coupled hydro-elastic time-domain solution. The problem is resolved by the finite element method

  1. Acceleration of low energy charged particles by gravitational waves

    E-print Network

    G. Voyatzis; L. Vlahos; S. Ichtiaroglou; D. Papadopoulos

    2005-12-07

    The acceleration of charged particles in the presence of a magnetic field and gravitational waves is under consideration. It is shown that the weak gravitational waves can cause the acceleration of low energy particles under appropriate conditions. Such conditions may be satisfied close to the source of the gravitational waves if the magnetized plasma is in a turbulent state.

  2. Submerged cylinder wave energy device - Theory and experiment

    Microsoft Academic Search

    D. V. Evans; D. C. Jeffrey; S. H. Salter; J. R. M. Taylor

    1979-01-01

    Linearized water wave theory is used to show that a submerged long circular cylinder suitably constrained by springs and dampers to make small harmonic oscillations, can be extremely efficient in absorbing the energy in an incident regular wave whose crests are parallel to the axis of the cylinder. Experimental results are described which confirm the theory for small amplitude waves

  3. Design and characterization of an ultrasonic lamb-wave power delivery system.

    PubMed

    Kural, Aleksander; Pullin, Rhys; Holford, Karen; Lees, Jonathan; Naylon, Jack; Paget, Christophe; Featherston, Carol

    2013-06-01

    In this paper, a novel design for an ultrasonic power transmission system designed for use in aircraft structural monitoring systems is described. The prototype system uses ultrasonic Lamb waves to carry energy along plates, such as those used in aircraft structures, and commercially available piezoelectric patch transducers as the transmitter and receiver. This sets it apart from other acoustic power transmission systems reported to date. The optimum configuration transmitted 12.7 mW of power across a distance of 54 cm in a 1.5-mm-thick aluminum plate, while being driven by a 20-Vpp, 35-kHz sinusoidal electric signal. This is in the same order of magnitude as the power required by the wireless sensors nodes of a structural health monitoring system currently being developed by Cardiff University and its partners. Thus, the power transmission system can be considered a viable component of the power source combination considered for the sensor nodes, which will also include vibration and thermal energy harvesting. The paper describes the design and optimization of the transmission and reception circuits with the use of inductive compensation. The use of laser vibrometry to characterize the transducers and to understand the signal propagation between them is also reported. PMID:25004476

  4. Power management in energy harvesting sensor networks

    Microsoft Academic Search

    Aman Kansal; Jason Hsu; Sadaf Zahedi; Mani B. Srivastava

    2007-01-01

    Power management is an important concern in sensor networks, because a tethered energy infrastructure is usually not available and an obvious concern is to use the available battery energy efficiently. However, in some of the sensor networking applications, an additional facility is available to ameliorate the energy problem: harvesting energy from the environment. Certain considerations in using an energy harvesting

  5. Computational fluid dynamics model of the artificial upwelling powered by surface waves

    NASA Astrophysics Data System (ADS)

    Soloviev, A.

    2014-12-01

    A number of studies during the last few decades were devoted to the artificial upwelling powered by surface waves. Potential applications of this system include an increase of supply of nutrients to the surface water to support sea farming and a local reduction of surface temperature in coastal waters. The system represents a pipeline attached to a buoy. Pumping of deep water takes place due to a valve located at the top end of the tube (Vershinsky et al. 1984; Liu et al. 1999). On the way up the system pumps deep water and on the way down it ejects the deep water in the surface layer. This system can be classified as a wave-driven inertial pump and is very effective in bringing deeper water to the surface. However, the deep water has tendency to sink, producing an effluent plume. In this work, a prototype, 3D computational fluid dynamics model of the wave-driven artificial upwelling has been developed. The model is implemented in the ANSYS Fluent software and is able to simulate dynamics of the wave following buoy system and dilution of the deep water in the upper layer of the ocean under various stratification and surface wave conditions. The model results are compared with available field data. Liu, C.C.K., Dai, J., Lin, H., and Guo, F. (1999). Hydrodynamic performance of wave-drive artificial upwelling, J. Engrg. Mech., ASCE, 125(7), 728-732. Vershinsky, N.V., Pshenichny, B.P., and Soloviev, A.V. (1987). Artificial upwelling using the energy of surface waves. Oceanology 27(3), 400-402.

  6. Power scaling of continuous-wave and Q-switched hybrid fiber-bulk erbium lasers at 1645 nm

    Microsoft Academic Search

    D. Y. Shen; J. K. Sahu; W. A. Clarkson

    We report recent progress in the development of high-power Er,Yb fiber-laser-pumped Er:YAG lasers at 1645 nm operating in continous-wave and Q-switched regimes. Strategies for further scaling of output power and pulse energy are considered. Summary: Solid-state laser sources operating in the eyesafe wavelength regime around ~1.5-1.6 ?m have numerous applications and provide a good starting point for mid-infrared generation via

  7. Optimal latching control of a wave energy device in regular and irregular waves

    Microsoft Academic Search

    A. Babarit; A. H. Clément

    2006-01-01

    This paper describes two methods which can be used to assess the benefit that latching control can bring to the efficiency of wave energy converters. The first method is based on the analytical solution of the equation of motion of the Wave Energy Converter (WEC) in the time domain, using matrix exponentials; it can be used to compute the optimal

  8. Bonneville Power Administration's Purchasing of Energy Savings 

    E-print Network

    Schick, H.

    1985-01-01

    The Bonneville Power Administration (BPA) is conducting a commercial buildings retrofit program in the Pacific Northwest by making payments to a sponsor, such as an energy service company or architectural and engineering firm, for energy savings...

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

    E-print Network

    Lee, Frank M; Swinney, Harry L; Morrison, P J

    2014-01-01

    We present a method to determine, using only velocity field data, the time-averaged energy flux $\\left$ and total radiated power $P$ for two-dimensional internal gravity waves. Both $\\left$ and $P$ are determined from expressions involving only a scalar function, the stream function $\\psi$. 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 ed...

  10. Energy function analysis for power system stability

    Microsoft Academic Search

    M. A. Pai

    1989-01-01

    Energy Function Analysis for Power System Stability presents the concept of energy function, which has found wide-spread applications for power systems in recent years. The most recent advances in five distinct areas are reviewed: Development of energy functions for structure preserving models, which can incorporate non-linear load models; energy functions which include a detailed model of the generating unit (i.e.

  11. Loss of energy of internal solitary wave over underwater obstacle

    NASA Astrophysics Data System (ADS)

    Talipova, Tatiana; Terletska, Katherina; Maderich, Vladimir; Brovchenko, Igor; Jung, Kyung-Tae; Pelinovsky, Efim; Grimshaw, Roger

    2014-05-01

    Internal waves are considered as the main reason of mixing of the stratified ocean waters. They loss their energy for mixing processes when dissipate on the ocean shelves. The elementary act of interaction of an internal solitary wave with a bottom step is studied to estimate the energy loss of an incident internal solitary wave. It is studied numerically in a computing tank in the approximation of two-layer flow within the full Navier - Stokes equations. Five different regimes of internal solitary wave interaction were identified within the full range of ratios of height of bottom layer after the step to the incident wave amplitude: (1) weak interaction, when wave dynamics can fully described by weakly nonlinear theory, (2) moderate interaction when wave breaking mechanism over the step is mainly shear instability, (3) strong interaction when supercritical flow in the step vicinity results in backward jet and vortices for depression waves and in a forward moving vortex (bolus) transporting dense fluid on the step, (4) transitional regime of interaction at the step height between splash on the step and (5) complete reflection from the step, and reflection regime when almost all energy transfers to the energy of reflected wave. The mechanism of KH instability takes place for reasonable amplitude waves of both depression and elevation during interaction with the bottom step for all regimes except regime (1). For this two-layer flow the energy loss due to an internal solitary wave interacting with the bottom step does not exceed 50% of the energy of the incident wave. The maximum of energy loss an elevation incident wave is reached when the ratio of the height of bottom layer after the step to incident wave amplitude equals zero. For an incident depression wave this ratio in maximum of energy loss is close to one. Self-similarities of the energy loss versus the ratio of the height of upper layer after the step to incident wave amplitude take place for the values more than -0.75 for elevation ISW and for more than 0.5 for depression ISW. It is shown that incident depression ISW in the transitional regime reflects with the formation of secondary solitary waves of opposite polarity after the step. Finally, the numerical modeling of ISW interacting with a bottom step agrees well with results of laboratory experiments for internal wave transformation over steep obstacles. We conclude that results obtained for idealized geometry can be useful for interpretation of the complicated processes of ISW interaction with steep sills, steep slope and shelves and underwater structures in coastal ocean and lakes. TT, KT, IB, VM and EP thank grant RFBR13-05-90424.

  12. Wave energy dissipation by intertidal sand waves on a mixed-sediment Beach

    USGS Publications Warehouse

    Adams, P.; Ruggiero, P.

    2006-01-01

    Within the surf zone, the energy expended by wave breaking is strongly influenced by nearshore bathymetry, which is often linked to the character and abundance of local sediments. Based upon a continuous, two year record of Argus Beach Monitoring System (ABMS) data on the north shore of Kachemak Bay in southcentral Alaska, we model the enhancement of wave energy dissipation by the presence of intertidal sand waves. Comparison of model results from simulations in the presence and absence of sand waves illustrates that these ephemeral morphological features can offer significant protection to the backing beach and sea cliff through two mechanisms: (1) by moving the locus of wave breaking seaward and (2) by increasing energy expenditure associated with the turbulence of wave breaking. Copyright ASCE 2006.

  13. Experimental study on a pendulum wave energy converter

    NASA Astrophysics Data System (ADS)

    Qiu, Shou-qiang; Ye, Jia-wei; Wang, Dong-jiao; Liang, Fu-lin

    2013-06-01

    Many of the existing wave energy converters (WEC) are of oscillating water column (OWC) and point absorber (PA) types. Fewer references have been published in public on the pendulum type WEC. A series of experimental tests on a bottom-hinged pendulum WEC model are carried out and some results are revealed in the present study. The purpose of this paper is to present a detailed description of the tests. It is found that wave energy conversion efficiency varies with the applied damping and wave conditions. In addition, special attention is given to the effect of the water ballast on the efficiency of the wave energy converter. It is demonstrated that the ballast plays an important role in energy extraction. Better understanding on how the performance of the device is influenced by damping, wave height, wave period and ballast is shown.

  14. Electron density measurements during microwave generation in a high power backward-wave oscillator

    Microsoft Academic Search

    Frank Hegeler; Chris Grabowski; Edl Schamiloglu

    1998-01-01

    Laser interferometry is used for the first time to measure plasma electron density along the slow wave structure (SWS) wall during microwave generation in a vacuum, long pulse, high power backward-wave oscillator (BWO). The University of New Mexico long pulse backward-wave oscillator, which displays the characteristic pulse shortening phenomenon, is investigated in these studies. Although pulse shortening is observed across

  15. Powerful surface-wave oscillators with two-dimensional periodic structures

    SciTech Connect

    Ginzburg, N. S.; Zaslavsky, V. Yu. [Radiophysical Department of Nizhny Novgorod State University, 23 Gagarin Ave., Nizhny Novgorod 603950 (Russian Federation); Institute of Applied Physics RAS, 46 Ulyanov street, Nizhny Novgorod 603950 (Russian Federation); Malkin, A. M.; Sergeev, A. S. [Institute of Applied Physics RAS, 46 Ulyanov street, Nizhny Novgorod 603950 (Russian Federation)

    2012-04-02

    We propose planar relativistic surface-wave oscillators with two-dimensional periodic gratings. Additional transverse propagating waves emerging on these gratings synchronize the emission from the wide sheet rectilinear electron beam which allows realizing a Cherenkov millimeter wave oscillator with gigawatt output power.

  16. High power continuous-wave titanium:sapphire laser

    DOEpatents

    Erbert, Gaylen V. (Livermore, CA); Bass, Isaac L. (Castro Valley, CA); Hackel, Richard P. (Livermore, CA); Jenkins, Sherman L. (Livermore, CA); Kanz, Vernon K. (Livermore, CA); Paisner, Jeffrey A. (Danville, CA)

    1993-01-01

    A high-power continuous-wave laser resonator (10) is provided, wherein first, second, third, fourth, fifth and sixth mirrors (11-16) form a double-Z optical cavity. A first Ti:Sapphire rod (17) is disposed between the second and third mirrors (12,13) and at the mid-point of the length of the optical cavity, and a second Ti:Sapphire rod (18) is disposed between the fourth and fifth mirrors (14,15) at a quarter-length point in the optical cavity. Each Ti:Sapphire rod (17,18) is pumped by two counter-propagating pump beams from a pair of argon-ion lasers (21-22, 23-24). For narrow band operation, a 3-plate birefringent filter (36) and an etalon (37) are disposed in the optical cavity so that the spectral output of the laser consists of 5 adjacent cavity modes. For increased power, seventy and eighth mirrors (101, 192) are disposed between the first and second mirrors (11, 12) to form a triple-Z optical cavity. A third Ti:Sapphire rod (103) is disposed between the seventh and eighth mirrors (101, 102) at the other quarter-length point in the optical cavity, and is pumped by two counter-propagating pump beams from a third pair of argon-ion lasers (104, 105).

  17. High power continuous-wave titanium:sapphire laser

    DOEpatents

    Erbert, G.V.; Bass, I.L.; Hackel, R.P.; Jenkins, S.L.; Kanz, V.K.; Paisner, J.A.

    1993-09-21

    A high-power continuous-wave laser resonator is provided, wherein first, second, third, fourth, fifth and sixth mirrors form a double-Z optical cavity. A first Ti:sapphire rod is disposed between the second and third mirrors and at the mid-point of the length of the optical cavity, and a second Ti:sapphire rod is disposed between the fourth and fifth mirrors at a quarter-length point in the optical cavity. Each Ti:sapphire rod is pumped by two counter-propagating pump beams from a pair of argon-ion lasers. For narrow band operation, a 3-plate birefringent filter and an etalon are disposed in the optical cavity so that the spectral output of the laser consists of 5 adjacent cavity modes. For increased power, seventy and eighth mirrors are disposed between the first and second mirrors to form a triple-Z optical cavity. A third Ti:sapphire rod is disposed between the seventh and eighth mirrors at the other quarter-length point in the optical cavity, and is pumped by two counter-propagating pump beams from a third pair of argon-ion lasers. 5 figures.

  18. Energy dissipation of wind-generated waves and whitecap coverage

    Microsoft Academic Search

    Paul A. Hwang; Mark A. Sletten

    2008-01-01

    The energy dissipation per unit area of the ocean surface attributed to fetch- or duration-limited wind-generated waves can be expressed in terms of wind speed, significant wave height and peak wave frequency. Such a parameterization equation can be exploited for obtaining a first order estimation of the rate of energy input through the air-sea interface in the world's oceans using

  19. A novel slotted helix slow-wave structure for high power Ka-band traveling-wave tubes

    NASA Astrophysics Data System (ADS)

    Liu, Lu-Wei; Wei, Yan-Yu; Wang, Shao-Meng; Hou, Yan; Yin, Hai-Rong; Zhao, Guo-Qing; Duan, Zhao-Yun; Xu, Jin; Gong, Yu-Bin; Wang, Wen-Xiang; Yang, Ming-Hua

    2013-10-01

    A novel slotted helix slow-wave structure (SWS) is proposed to develop a high power, wide-bandwidth, and high reliability millimeter-wave traveling-wave tube (TWT). This novel structure, which has higher heat capacity than a conventional helix SWS, evolves from conventional helix SWS with three parallel rows of rectangular slots made in the outside of the helix tape. In this paper, the electromagnetic characteristics and the beam-wave interaction of this novel structure operating in the Ka-band are investigated. From our calculations, when the designed beam voltage and beam current are set to be 18.45 kV and 0.2 A, respectively, this novel circuit can produce over 700-W average output power in a frequency range from 27.5 GHz to 32.5 GHz, and the corresponding conversion efficiency values vary from 19% to 21.3%, and the maximum output power is 787 W at 30 GHz.

  20. Power electronics and alternative energy generation

    Microsoft Academic Search

    James P Lyons; Vlatko Vlatkovic

    2004-01-01

    Growth in alterative energy generation technologies and markets will have a major impact on the development of power electronics in the future. The paper discusses some of these implications, and outlines the technological and performance challenges for power electronic systems in alternative energy applications.

  1. From solar energy to mechanical power

    Microsoft Academic Search

    Fujii

    1990-01-01

    This book describes general methods of converting solar thermal energy to mechanical power, concentrating particularly on those having a small or moderate conversion scale. Beginning with a historical overview and an outline of requirements for a solar-mechanical power conversion system, the book describes in detail several energy conversion system, paying particular attention to the Rankine, Stirling and Brayton cycle engines.

  2. Energy storage options for space power

    Microsoft Academic Search

    H. W. Hoffman; J. F. Martin; M. Olszewski

    1985-01-01

    Including energy storage in a space power supply enhances the feasibility of using thermal power cycles (Rankine or Brayton) and providing high-power pulses. Review of storage options (superconducting magnets, capacitors, electrochemical batteries, thermal phase-change materials (PCM), and flywheels) suggests that flywheels and phase-change devices hold the most promise. Latent heat storage using inorganic salts and metallic eutectics offers thermal energy

  3. Novel surface wave exciters for power line fault detection and communications

    Microsoft Academic Search

    M. N. Alam; R. H. Bhuiyan; R. Dougal; M. Ali

    2011-01-01

    A novel conformal surface wave (CSW) exciter is introduced which can excite electromagnetic (EM) surface waves along unshielded power line cables non-intrusively. The CSW exciter is small, cost effective and can be easily placed on a power cable compared to conventional monopole type launchers or horn type launchers. Besides cable fault detection, the potential applications of the proposed exciter include

  4. Nylon fibre rope moorings for wave energy converters

    Microsoft Academic Search

    I. M. L. Ridge; S. J. Banfield; J. Mackay

    2010-01-01

    The wave energy market has traditionally employed mooring concepts adopted from the mature technology of the oil and gas industry. However, this approach may not always be appropriate to satisfy the particular requirements of Wave Energy Converter (WEC) mooring systems, especially the need for very compliant moorings. Specific challenges are: the huge 1st order motion induced forces generated by storm

  5. Linear generators for direct-drive wave energy conversion

    Microsoft Academic Search

    H. Polinder; B. C. Mecrow; A. G. Jack; P. Dickinson; M. A. Mueller

    2003-01-01

    The Archimedes Wave Swing (AWS) is a system that converts ocean wave energy into electric energy. The goal of the research described in this paper is to identify the most suitable generator type for this application. Of the more conventional generator types, the three-phase permanent-magnet synchronous generator with iron in both stator and translator is most suitable, because it is

  6. Fluctuations of energy flux in wave turbulence Eric Falcon,1

    E-print Network

    Falcon, Eric

    Fluctuations of energy flux in wave turbulence ´Eric Falcon,1 S´ebastien Auma^itre,2 Claudio Falc gravity and capillary wave turbulence in a statistically stationary regime displays fluctuations much interactions transfer kinetic energy toward small scales where viscous dissipation takes place

  7. Nuclear Power Trends Energy Economics and Sustainability

    E-print Network

    Nuclear Power Trends Energy Economics and Sustainability L. H. Tsoukalas Purdue University Nuclear;National Research Council of Greece, May 8, 2008 Outline · The Problem · Nuclear Energy Trends · Energy Economics · Life Cycle Analysis · Nuclear Sustainability · Nuclear Energy in Greece? #12;National Research

  8. A direct current rectification scheme for microwave space power conversion using traveling wave electron acceleration

    NASA Technical Reports Server (NTRS)

    Manning, Robert M.

    1993-01-01

    The formation of the Vision-21 conference held three years ago allowed the present author to reflect and speculate on the problem of converting electromagnetic energy to a direct current by essentially reversing the process used in traveling wave tubes that converts energy in the form of a direct current to electromagnetic energy. The idea was to use the electric field of the electromagnetic wave to produce electrons through the field emission process and accelerate these electrons by the same field to produce an electric current across a large potential difference. The acceleration process was that of cyclotron auto-resonance. Since that time, this rather speculative ideas has been developed into a method that shows great promise and for which a patent is pending and a prototype design will be demonstrated in a potential laser power beaming application. From the point of view of the author, a forum such as Vision-21 is becoming an essential component in the rather conservative climate in which our initiatives for space exploration are presently formed. Exchanges such as Vision-21 not only allows us to deviate from the 'by-the-book' approach and rediscover the ability and power in imagination, but provides for the discussion of ideas hitherto considered 'crazy' so that they may be given the change to transcend from the level of eccentricity to applicability.

  9. A Full-Wave Rectifier With Integrated Peak Selection for Multiple Electrode Piezoelectric Energy Harvesters

    Microsoft Academic Search

    Nathaniel J. Guilar; Rajeevan Amirtharajah; Paul J. Hurst

    2009-01-01

    Piezoelectric transducers are a viable way of harvesting vibrational energy for low power embedded systems such as wireless sensors. A proposed disk-shaped piezoelectric transducer with several electrodes enables increased energy harvesting from multiple mechanical resonances. To rectify the low-frequency AC voltage from harvested vibrational energy, a full-wave rectifier has been fabricated in 0.35 mum CMOS. Integrated peak selection circuitry allows

  10. Wave propagation downstream of a high power helicon in a dipolelike magnetic field

    SciTech Connect

    Prager, James; Winglee, Robert; Roberson, B. Race [Department of Earth and Space Science, University of Washington, Johnson Hall Rm-070, Box 351310, 4000 15th Avenue NE, Seattle, Washington 98195-1310 (United States); Ziemba, Timothy [Eagle Harbor Technologies, Inc., Suite D3 179, 321 Highschool RD NE, Bainbridge Island, Washington 98110-1697 (United States)

    2010-01-15

    The wave propagating downstream of a high power helicon source in a diverging magnetic field was investigated experimentally. The magnetic field of the wave has been measured both axially and radially. The three-dimensional structure of the propagating wave is observed and its wavelength and phase velocity are determined. The measurements are compared to predictions from helicon theory and that of a freely propagating whistler wave. The implications of this work on the helicon as a thruster are also discussed.

  11. THE FORCE OF A TSUNAMI ON A WAVE ENERGY CONVERTER LAURA O'BRIEN, PAUL CHRISTODOULIDES, EMILIANO RENZI, DENYS DUTYKH,

    E-print Network

    THE FORCE OF A TSUNAMI ON A WAVE ENERGY CONVERTER LAURA O'BRIEN, PAUL CHRISTODOULIDES, EMILIANO resources, wave power technology is fast becoming a realistic solution. However, the recent tsunami in Japan was a harsh reminder of the ferocity of the ocean. It is known that tsunamis are nearly undetectable

  12. Pulsed Power Driven Fusion Energy

    SciTech Connect

    SLUTZ,STEPHEN A.

    1999-11-22

    Pulsed power is a robust and inexpensive technology for obtaining high powers. Considerable progress has been made on developing light ion beams as a means of transporting this power to inertial fusion capsules. However, further progress is hampered by the lack of an adequate ion source. Alternatively, z-pinches can efficiently convert pulsed power into thermal radiation, which can be used to drive an inertial fusion capsule. However, a z-pinch driven fusion explosion will destroy a portion of the transmission line that delivers the electrical power to the z-pinch. They investigate several options for providing standoff for z-pinch driven fusion. Recyclable Transmission Lines (RTLs) appear to be the most promising approach.

  13. Compact inductive energy storage pulse power system

    NASA Astrophysics Data System (ADS)

    K, Senthil; Mitra, S.; Roy, Amitava; Sharma, Archana; Chakravarthy, D. P.

    2012-05-01

    An inductive energy storage pulse power system is being developed in BARC, India. Simple, compact, and robust opening switches, capable of generating hundreds of kV, are key elements in the development of inductive energy storage pulsed power sources. It employs an inductive energy storage and opening switch power conditioning techniques with high energy density capacitors as the primary energy store. The energy stored in the capacitor bank is transferred to an air cored storage inductor in 5.5 ?s through wire fuses. By optimizing the exploding wire parameters, a compact, robust, high voltage pulse power system, capable of generating reproducibly 240 kV, is developed. This paper presents the full details of the system along with the experimental data.

  14. A dynamometer set up for simulation of a wave energy operated Wells turbine

    Microsoft Academic Search

    S. S. Y. Narayanan; S. Bose

    1996-01-01

    The present trend in the world is to go for ecologically friendly methods of power generation. In this paper a dynamometer set up simulating a wave energy driven Wells turbine with proper scaling is proposed. This is a new dynamic drive test set up for evaluation of alternative generator configurations. Open loop and closed loop (P, PI and PLL controllers

  15. Energy $ Savings From Power Capacitors

    E-print Network

    Harder, J. E.

    1982-01-01

    penalty or a reduction in the kVA demand, or a similar reduction in the power bill for improved power factor. In addition, some users will add power capacitors to improve voltage regulation or reduce the loading of heavily loaded transformers... (TL) of a transformer can be divided into no load loss (NL) and load loss (LL) where: TL .. NL + LL The no load loss is affected very little by the addition of capacitors. The load loss varies as the square of the current or the square of the k...

  16. Energy dissipation in wave propagation in general relativistic plasma

    E-print Network

    Ajanta Das; S. Chatterjee

    2009-11-03

    Based on a recent communication by the present authors the question of energy dissipation in magneto hydrodynamical waves in an inflating background in general relativity is examined. It is found that the expanding background introduces a sort of dragging force on the propagating wave such that unlike the Newtonnian case energy gets dissipated as it progresses. This loss in energy having no special relativistic analogue is, however, not mechanical in nature as in elastic wave. It is also found that the energy loss is model dependent and also depends on the number of dimensions.

  17. Wave spectral energy variability in the northeast Pacific

    USGS Publications Warehouse

    Bromirski, P.D.; Cayan, D.R.; Flick, R.E.

    2005-01-01

    The dominant characteristics of wave energy variability in the eastern North Pacific are described from NOAA National Data Buoy Center (NDBC) buoy data collected from 1981 to 2003. Ten buoys at distributed locations were selected for comparison based on record duration and data continuity. Long-period (LP) [T > 12] s, intermediate-period [6 ??? T ??? 12] s, and short-period [T < 6] s wave spectral energy components are considered separately. Empirical orthogonal function (EOF) analyses of monthly wave energy anomalies reveal that all three wave energy components exhibit similar patterns of spatial variability. The dominant mode represents coherent heightened (or diminished) wave energy along the West Coast from Alaska to southern California, as indicated by composites of the 700 hPa height field. The second EOF mode reveals a distinct El Nin??o-Southern Oscillation (ENSO)-associated spatial distribution of wave energy, which occurs when the North Pacific storm track is extended unusually far south or has receded to the north. Monthly means and principal components (PCs) of wave energy levels indicate that the 1997-1998 El Nin??o winter had the highest basin-wide wave energy within this record, substantially higher than the 1982-1983 El Nin??o. An increasing trend in the dominant PC of LP wave energy suggests that storminess has increased in the northeast Pacific since 1980. This trend is emphasized at central eastern North Pacific locations. Patterns of storminess variability are consistent with increasing activity in the central North Pacific as well as the tendency for more extreme waves in the south during El Nin??o episodes and in the north during La Nin??a. Copyright 2005 by the American Geophysical Union.

  18. Optimizing a Hybrid Energy Storage System for a Virtual Power Plant for Improved Wind Power

    E-print Network

    Teodorescu, Remus

    Optimizing a Hybrid Energy Storage System for a Virtual Power Plant for Improved Wind Power power plant. In this paper it means the combination of the hybrid energy storage system and wind power. Index Terms--Virtual power plant, hybrid energy storage, wind power, sizing energy storage 1

  19. Energy and energy flux in axisymmetric slow and fast waves

    NASA Astrophysics Data System (ADS)

    Moreels, M. G.; Van Doorsselaere, T.; Grant, S. D. T.; Jess, D. B.; Goossens, M.

    2015-06-01

    Aims: We aim to calculate the kinetic, magnetic, thermal, and total energy densities and the flux of energy in axisymmetric sausage modes. The resulting equations should contain as few parameters as possible to facilitate applicability for different observations. Methods: The background equilibrium is a one-dimensional cylindrical flux tube model with a piecewise constant radial density profile. This enables us to use linearised magnetohydrodynamic equations to calculate the energy densities and the flux of energy for axisymmetric sausage modes. Results: The equations used to calculate the energy densities and the flux of energy in axisymmetric sausage modes depend on the radius of the flux tube, the equilibrium sound and Alfvén speeds, the density of the plasma, the period and phase speed of the wave, and the radial or longitudinal components of the Lagrangian displacement at the flux tube boundary. Approximate relations for limiting cases of propagating slow and fast sausage modes are also obtained. We also obtained the dispersive first-order correction term to the phase speed for both the fundamental slow body mode under coronal conditions and the slow surface mode under photospheric conditions. Appendix A is available in electronic form at http://www.aanda.org

  20. Design and Analysis for a Floating Oscillating Surge Wave Energy Converter: Preprint

    SciTech Connect

    Yu, Y. H.; Li, Y.; Hallett, K.; Hotimsky, C.

    2014-03-01

    This paper presents a recent study on the design and analysis of an oscillating surge wave energy converter. A successful wave energy conversion design requires the balance between the design performance and cost. The cost of energy is often used as the metric to judge the design of the wave energy conversion system. It is often determined based on the device power performance, the cost for manufacturing, deployment, operation and maintenance, as well as the effort to ensure the environmental compliance. The objective of this study is to demonstrate the importance of a cost driven design strategy and how it can affect a WEC design. Three oscillating surge wave energy converter (OSWEC) designs were used as the example. The power generation performance of the design was modeled using a time-domain numerical simulation tool, and the mass properties of the design were determined based on a simple structure analysis. The results of those power performance simulations, the structure analysis and a simple economic assessment were then used to determine the cost-efficiency of selected OSWEC designs. Finally, a discussion on the environmental barrier, integrated design strategy and the key areas that need further investigation is also presented.

  1. Laser energy converted into electric power

    NASA Technical Reports Server (NTRS)

    Shimada, K.

    1973-01-01

    Apparatus verifies concepts of converting laser energy directly into electric energy. Mirror, placed in beam and inclined at angle to it, directs small amount of incident radiation to monitor which establishes precise power levels and other beam characteristics. Second mirror and condensing lens direct bulk of laser energy into laser plasmadynamic converter.

  2. Second Proof Work, Power, and Energy

    E-print Network

    Kostic, Milivoje M.

    , United States 1. Basic Concepts 2. Forms, Classifications, and Conservation of Energy 3. Work that they will be depleted in a finite time period at the current rate of consumption. power The energy rate per unit of time. renewable energy sources The continuously or frequently available (renewed daily or at least annually

  3. Energy Storage for the Power Grid

    SciTech Connect

    Imhoff, Carl; Vaishnav, Dave

    2014-07-01

    The iron vanadium redox flow battery was developed by researchers at Pacific Northwest National Laboratory as a solution to large-scale energy storage for the power grid. This technology provides the energy industry and the nation with a reliable, stable, safe, and low-cost storage alternative for a cleaner, efficient energy future.

  4. Open cycle traveling wave thermoacoustics: Energy fluxes and thermodynamics

    Microsoft Academic Search

    Nathan T. Weiland; Ben T. Zinn

    2004-01-01

    In an open cycle traveling wave thermoacoustic engine, hot gas steadily flows into the hot side of the regenerator, replacing the hot heat exchanger as the primary energy source for the engine. In such an engine, interactions between the acoustic, convective, conductive and thermoacoustic energy fluxes facilitate conversion of the input thermal energy into acoustic energy. This study describes the

  5. The Black Sea Wave Energy: The Present State and the Twentieth century Changes

    E-print Network

    Galabov, Vasko

    2015-01-01

    In this paper we present a study of the present state of the Black Sea wave energy. The studies of other authors are based on the use of input data from atmospheric reanalysis or a downscaling of such reanalysis. Instead of reanalysis data, we use input data from the operational limited area numerical weather prediction model ALADIN. We showed that the estimations of the Black Sea wave energy based on reanalyses deviate significantly from the real potential. We showed also that the highest values of the mean annual wave power flux is between 4.5 and 5.0 kW/m2 and the near shore areas with the highest wave energy potential are the southernmost Bulgarian coast and the coast of Turkey north of Istanbul. While we showed that the wind data from the reanalysis are not useful for the estimation of the actual wave energy potential, we claimed that the reanalysis data is useful to study the long term changes of the wave energy of the Black Sea. We used the 10m winds from the recent ERA-20C reanalysis, which covers the...

  6. Energy storage options for space power

    Microsoft Academic Search

    H. W. Hoffman; J. F. Martin; M. Olszewski

    1987-01-01

    Including energy storage in a space power supply enhances the feasibility of using thermal power cycles (Rankine or Brayton) and providing high-power pulses. Superconducting magnets, capacitors, electrochemical batteries, thermal phase-change materials (PCM), and flywheels are assessed; the results obtained suggest that flywheels and phase-change devices hold the most promise. Latent heat storage using inorganic salts and metallic eutectics offers thermal

  7. SPS Energy Conversion Power Management Workshop

    NASA Astrophysics Data System (ADS)

    1980-06-01

    Energy technology concerning photovoltaic conversion, solar thermal conversion systems, and electrical power distribution processing is discussed. The manufacturing processes involving solar cells and solar array production are summarized. Resource issues concerning gallium arsenides and silicon alternatives are reported. Collector structures for solar construction are described and estimates in their service life, failure rates, and capabilities are presented. Theories of advanced thermal power cycles are summarized. Power distribution system configurations and processing components are presented.

  8. SPS Energy Conversion Power Management Workshop

    NASA Technical Reports Server (NTRS)

    1980-01-01

    Energy technology concerning photovoltaic conversion, solar thermal conversion systems, and electrical power distribution processing is discussed. The manufacturing processes involving solar cells and solar array production are summarized. Resource issues concerning gallium arsenides and silicon alternatives are reported. Collector structures for solar construction are described and estimates in their service life, failure rates, and capabilities are presented. Theories of advanced thermal power cycles are summarized. Power distribution system configurations and processing components are presented.

  9. Relationship between directions of wave and energy propagation for cold plasma waves

    NASA Technical Reports Server (NTRS)

    Musielak, Zdzislaw E.

    1986-01-01

    The dispersion relation for plasma waves is considered in the 'cold' plasma approximation. General formulas for the dependence of the phase and group velocities on the direction of wave propagation with respect to the local magnetic field are obtained for a cold magnetized plasma. The principal cold plasma resonances and cut-off frequencies are defined for an arbitrary angle and are used to establish basic regimes of frequency where the cold plasma waves can propagate or can be evanescent. The relationship between direction of wave and energy propagation, for cold plasma waves in hydrogen atmosphere, is presented in the form of angle diagrams (angle between group velocity and magnetic field versus angle between phase velocity and magnetic field) and polar diagrams (also referred to as 'Friedrich's diagrams') for different directions of wave propagation. Morphological features of the diagrams as well as some critical angles of propagation are discussed.

  10. Cross-Layer Design for Low-Power Wireless Sensor Node Using Wave Clock

    NASA Astrophysics Data System (ADS)

    Takeuchi, Takashi; Otake, Yu; Ichien, Masumi; Gion, Akihiro; Kawaguchi, Hiroshi; Ohta, Chikara; Yoshimoto, Masahiko

    We propose Isochronous-MAC (I-MAC) using the Long-Wave Standard Time Code (so called “wave clock”), and introduce cross-layer design for a low-power wireless sensor node with I-MAC. I-MAC has a periodic wakeup time synchronized with the actual time, and thus we take the wave clock. However, a frequency of a crystal oscillator varies along with temperature, which incurs a time difference among nodes. We present a time correction algorithm to address this problem, and shorten the time difference. Thereby, the preamble length in I-MAC can be minimized, which saves communication power. For further power reduction, a low-power crystal oscillator is also proposed, as a physical-layer design. We implemented I-MAC on an off-the-shelf sensor node to estimate the power saving, and verified that the proposed cross-layer design reduces 81% of the total power, compared to Low Power Listening.

  11. Energy Contents of Gravitational Waves in Teleparallel Gravity

    E-print Network

    M. Sharif; Sumaira Taj

    2009-10-02

    The conserved quantities, that are, gravitational energy-momentum and its relevant quantities are investigated for cylindrical and spherical gravitational waves in the framework of teleparallel equivalent of General Relativity using the Hamiltonian approach. For both cylindrical and spherical gravitational waves, we obtain definite energy and constant momentum. The constant momentum shows consistency with the results available in General Relativity and teleparallel gravity. The angular momentum for cylindrical and spherical gravitational waves also turn out to be constant. Further, we evaluate their gravitational energy-momentum fluxes and gravitational pressure.

  12. Energy of Alfven waves generated during magnetic reconnection

    E-print Network

    Wang, L C; Ma, Z W; Zhang, X; Lee, L C

    2015-01-01

    A new method for the determination of the Alfven wave energy generated during magnetic reconnection is introduced and used to analyze the results from two-dimensional MHD simulations. It is found that the regions with strong Alfven wave perturbations almost coincide with that where both magnetic-field lines and flow-stream lines are bent, suggesting that this method is reliable for identifying Alfven waves. The magnetic energy during magnetic reconnection is mainly transformed into the thermal energy. The conversion rate to Alfven wave energy from the magnetic energy is strongly correlated to the magnetic reconnection rate. The maximum conversion rate at the time with the peak reconnection rate is found to be only about 4% for the cases with the plasma beta=0.01,0.1, and 1.0.

  13. High-speed photographic investigation of underwater shock wave due to electric pulse power

    Microsoft Academic Search

    Masahiko Otsuka; Kouhei Inoue; Shigeru Itoh

    2005-01-01

    In recent years, researches of high energy emitted in a short time are performed actively. The high energy is used for manufacturing and forming. The propagation velocity of the reaction in a high energy explosive may reach the maximum about 10 km\\/s, and may be accompanied by the shock wave. Many products using the high pressure r the shock wave

  14. Wave Turbulence in Superfluid {sup 4}He: Energy Cascades and Rogue Waves in the Laboratory

    SciTech Connect

    Efimov, V. B. [Department of Physics, Lancaster University, Lancaster, LA1 4YB (United Kingdom); Institute of Solid State Physics RAS, Chernogolovka, Moscow region, 142432 (Russian Federation); Ganshin, A. N.; McClintock, P. V. E. [Department of Physics, Lancaster University, Lancaster, LA1 4YB (United Kingdom); Kolmakov, G. V. [Institute of Solid State Physics RAS, Chernogolovka, Moscow region, 142432 (Russian Federation); Currently at the Department of Chemical and Petroleum Engineering, Pittsburgh University, Pittsburgh, PA 15261 (United States); Mezhov-Deglin, L. P. [Institute of Solid State Physics RAS, Chernogolovka, Moscow region, 142432 (Russian Federation)

    2008-11-13

    Recent work on second sound acoustic turbulence in superfluid {sup 4}He is reviewed. Observations of forward and inverse energy cascades are described. The onset of the inverse cascade occurs above a critical driving energy and it is accompanied by giant waves that constitute an acoustic analogue of the rogue waves that occasionally appear on the surface of the ocean. The theory of the phenomenon is outlined and shown to be in good agreement with the experiments.

  15. Single-wave-number representation of nonlinear energy spectrum in elastic-wave turbulence of the Föppl-von Kármán equation: Energy decomposition analysis and energy budget

    NASA Astrophysics Data System (ADS)

    Yokoyama, Naoto; Takaoka, Masanori

    2014-12-01

    A single-wave-number representation of a nonlinear energy spectrum, i.e., a stretching-energy spectrum, is found in elastic-wave turbulence governed by the Föppl-von Kármán (FvK) equation. The representation enables energy decomposition analysis in the wave-number space and analytical expressions of detailed energy budgets in the nonlinear interactions. We numerically solved the FvK equation and observed the following facts. Kinetic energy and bending energy are comparable with each other at large wave numbers as the weak turbulence theory suggests. On the other hand, stretching energy is larger than the bending energy at small wave numbers, i.e., the nonlinearity is relatively strong. The strong correlation between a mode ak and its companion mode a-k is observed at the small wave numbers. The energy is input into the wave field through stretching-energy transfer at the small wave numbers, and dissipated through the quartic part of kinetic-energy transfer at the large wave numbers. Total-energy flux consistent with energy conservation is calculated directly by using the analytical expression of the total-energy transfer, and the forward energy cascade is observed clearly.

  16. Single-wave-number representation of nonlinear energy spectrum in elastic-wave turbulence of the Föppl-von Kármán equation: energy decomposition analysis and energy budget.

    PubMed

    Yokoyama, Naoto; Takaoka, Masanori

    2014-12-01

    A single-wave-number representation of a nonlinear energy spectrum, i.e., a stretching-energy spectrum, is found in elastic-wave turbulence governed by the Föppl-von Kármán (FvK) equation. The representation enables energy decomposition analysis in the wave-number space and analytical expressions of detailed energy budgets in the nonlinear interactions. We numerically solved the FvK equation and observed the following facts. Kinetic energy and bending energy are comparable with each other at large wave numbers as the weak turbulence theory suggests. On the other hand, stretching energy is larger than the bending energy at small wave numbers, i.e., the nonlinearity is relatively strong. The strong correlation between a mode a(k) and its companion mode a(-k) is observed at the small wave numbers. The energy is input into the wave field through stretching-energy transfer at the small wave numbers, and dissipated through the quartic part of kinetic-energy transfer at the large wave numbers. Total-energy flux consistent with energy conservation is calculated directly by using the analytical expression of the total-energy transfer, and the forward energy cascade is observed clearly. PMID:25615184

  17. A 35 GHz wireless millimeter-wave power sensor based on GaAs micromachining technology

    NASA Astrophysics Data System (ADS)

    Wang, De-bo; Liao, Xiao-ping

    2012-06-01

    A novel MEMS wireless millimeter-wave power sensor based on GaAs MMIC technology is presented in this paper. The principle of this wireless millimeter-wave power sensor is explained. It is designed and fabricated using MEMS technology and the GaAs MMIC process. With the millimeter-wave power range from 0.1 to 80 mW, the sensitivity of the wireless millimeter-wave power sensor is about 0.246 mV mW-1 at 35 GHz. In order to verify the power detection capability, this wireless power sensor is mounted on a PCB which influences the microwave performance of the CPW-fed antenna including the return loss and the radiation pattern. The frequency-dependent characteristic and the degree-dependent characteristic of this wireless power sensor are researched. Furthermore, in addition to the combination of the advantages of CPW-fed antenna with the advantages of the thermoelectric power sensor, another significant advantage of this wireless millimeter-wave power sensor is that it can be integrated with MMICs and other planar connecting circuit structures with zero dc power consumption. These features make it suitable for various applications ranging from the environment or space radiation detection systems to radar receiver and transmitter systems.

  18. From solar energy to mechanical power

    SciTech Connect

    Fujii, I.

    1990-01-01

    This book describes general methods of converting solar thermal energy to mechanical power, concentrating particularly on those having a small or moderate conversion scale. Beginning with a historical overview and an outline of requirements for a solar-mechanical power conversion system, the book describes in detail several energy conversion system, paying particular attention to the Rankine, Stirling and Brayton cycle engines. For each engine, the principles of operation, efficiency and performance are discussed and working examples of each type are described.

  19. Energy Content of Colliding Plane Waves using Approximate Noether Symmetries

    E-print Network

    M. Sharif; Saira Waheed

    2011-09-19

    This paper is devoted to study the energy content of colliding plane waves using approximate Noether symmetries. For this purpose, we use approximate Lie symmetry method of Lagrangian for differential equations. We formulate the first-order perturbed Lagrangian for colliding plane electromagnetic and gravitational waves. It is shown that in both cases, there does not exist

  20. Energies of ultrarelativistic electrons produced by an oblique shock wave

    Microsoft Academic Search

    Naoki Bessho; Yukiharu Ohsawa

    2000-01-01

    Production of ultrarelativistic electrons in an oblique magnetosonic shock wave is studied theoretically and numerically. First, the structure of the oblique shock wave is analytically discussed on the basis of a relativistic, two-fluid model. Then, by use of the field strengths thus obtained, the maximum energy of accelerated electrons is calculated as a function of the propagation speed and angle

  1. Wave-current interactions at the FloWave Ocean Energy Research Facility

    NASA Astrophysics Data System (ADS)

    Noble, Donald; Davey, Thomas; Steynor, Jeffrey; Bruce, Tom; Smith, Helen; Kaklis, Panagiotis

    2015-04-01

    Physical scale model testing is an important part of the marine renewable energy development process, allowing the study of forces and device behaviour in a controlled environment prior to deployment at sea. FloWave is a new state-of-the-art ocean energy research facility, designed to provide large scale physical modelling services to the tidal and wave sector. It has the unique ability to provide complex multi-directional waves that can be combined with currents from any direction in the 25m diameter circular tank. The facility is optimised for waves around 2s period and 0.4m height, and is capable of generating currents upwards of 1.6m/s. This offers the ability to model metocean conditions suitable for most renewable energy devices at a typical scale of between 1:10 and 1:40. The test section is 2m deep, which can be classed as intermediate-depth for most waves of interest, thus the full dispersion equation must be solved as the asymptotic simplifications do not apply. The interaction between waves and currents has been studied in the tank. This has involved producing in the tank sets of regular waves, focussed wave groups, and random sea spectra including multi-directional sea states. These waves have been both inline-with and opposing the current, as well as investigating waves at arbitrary angles to the current. Changes in wave height and wavelength have been measured, and compared with theoretical results. Using theoretical wave-current interaction models, methods have been explored to "correct" the wave height in the central test area of the tank when combined with a steady current. This allows the wave height with current to be set equal to that without a current. Thus permitting, for example, direct comparison of device motion response between tests with and without current. Alternatively, this would also permit a specific wave height and current combination to be produced in the tank, reproducing recorded conditions at a particular site of interest. The initial tests used a correction factor based on a linear combination of wave and current (Smith 1997), which was found to be reasonably accurate, although the requirement for higher order theory is also explored. FloWave is a new facility that offers the ability to study wave-current interactions at arbitrary angles with relatively fast currents. This is important as waves and tidal currents at sites of interest for renewable energy generation may not be aligned (Lewis et al. 2014), and so better understanding of these conditions is required. References Lewis, M.J. et al., 2014. Realistic wave conditions and their influence on quantifying the tidal stream energy resource. Applied Energy, 136, pp.495-508. Smith, J.M., 1997. Coastal Engineering Technical Note One-dimensional wave-current interaction (CETN IV-9), Vicksburg, MS.

  2. Physical measurements of breaking wave impact on a floating wave energy converter

    NASA Astrophysics Data System (ADS)

    Hann, Martyn R.; Greaves, Deborah M.; Raby, Alison

    2013-04-01

    Marine energy converter must both efficiently extract energy in small to moderate seas and also successfully survive storms and potential collisions. Extreme loads on devices are therefore an important consideration in their design process. X-MED is a SuperGen UKCMER project and is a collaboration between the Universities of Manchester, Edinburgh and Plymouth and the Scottish Association for Marine Sciences. Its objective is to extend the knowledge of extreme loads due to waves, currents, flotsam and mammal impacts. Plymouth Universities contribution to the X-MED project involves measuring the loading and response of a taut moored floating body due to steep and breaking wave impacts, in both long crested and directional sea states. These measurements are then to be reproduced in STAR-CCM+, a commercial volume of fluid CFD solver, so as to develop techniques to predict the wave loading on wave energy converters. The measurements presented here were conducted in Plymouth Universities newly opened COAST laboratories 35m long, 15.5m wide and 3m deep ocean basin. A 0.5m diameter taut moored hemispherical buoy was used to represent a floating wave energy device or support structure. The changes in the buoys 6 degree of freedom motion and mooring loads are presented due to focused breaking wave impacts, with the breaking point of the wave changed relative to the buoy.

  3. Space solar power - An energy alternative

    NASA Technical Reports Server (NTRS)

    Johnson, R. W.

    1978-01-01

    The space solar power concept is concerned with the use of a Space Power Satellite (SPS) which orbits the earth at geostationary altitude. Two large symmetrical solar collectors convert solar energy directly to electricity using photovoltaic cells woven into blankets. The dc electricity is directed to microwave generators incorporated in a transmitting antenna located between the solar collectors. The antenna directs the microwave beam to a receiving antenna on earth where the microwave energy is efficiently converted back to dc electricity. The SPS design promises 30-year and beyond lifetimes. The SPS is relatively pollution free as it promises earth-equivalence of 80-85% efficient ground-based thermal power plant.

  4. Energy storage and generation from thermopower waves

    E-print Network

    Abrahamson, Joel T. (Joel Theodore)

    2012-01-01

    The nonlinear coupling between an exothermic chemical reaction and a nanowire or nanotube with large axial heat conduction guides a self-propagating thermal wave along the nano-conduit. The thermal conduit accelerates the ...

  5. Wave energy driven resonant sea water pump

    SciTech Connect

    Czitrom, S.P.R. [UNAM, Mexico City (Mexico). Inst. de Ciencias del Mar y Limnologia

    1996-12-31

    A wave driven sea-water pump which operates by resonance is described. Oscillations in the resonant and exhaust ducts perform similar to two mass-spring systems coupled by a third spring acting for the compression chamber. Performance of the pump is optimized by means of a variable volume air compression chamber (patents pending) which tunes the system to the incoming wave frequency. Wave tank experiments with an instrumented, 1:20 scale model of the pump are described. Performance was studied under various wave and tuning conditions and compared to a numerical model which was found to describe the system accurately. Successful sea trials at an energetic coastline provide evidence of the system`s viability under demanding conditions.

  6. Saving Energy Through Advanced Power Strips (Poster)

    SciTech Connect

    Christensen, D.

    2013-10-01

    Advanced Power Strips (APS) look just like ordinary power strips, except that they have built-in features that are designed to reduce the amount of energy used by many consumer electronics. There are several different types of APSs on the market, but they all operate on the same basic principle of shutting off the supply power to devices that are not in use. By replacing your standard power strip with an APS, you can signifcantly cut the amount of electricity used by your home office and entertainment center devices, and save money on your electric bill. This illustration summarizes the different options.

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

    SciTech Connect

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

    2014-06-23

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

  8. The Physics Classroom: Waves and Energy Transport

    NSDL National Science Digital Library

    Tom Henderson

    This resource from Glenbrook High School in Glenview, Illinois explains and illustrates the nature, properties and behaviors of waves. The unique nature of a standing wave is also introduced and explained. Each lesson resembles the type and extent of coverage given to that physics topic in class. The sub-lessons are accompanied by Check Your Understanding sections, providing an opportunity to assess understanding of the lesson material.

  9. On the configuration of arrays of floating wave energy converters 

    E-print Network

    Child, Benjamin Frederick Martin

    2011-11-22

    In this thesis, certain issues relating to a number of wave energy absorbers operating in the same vicinity are investigated. Specifically, arrangements of the devices within such an array are sought, such that beneficial ...

  10. Internal wave energy radiated from a turbulent mixed layer

    SciTech Connect

    Munroe, James R., E-mail: jmunroe@mun.ca [Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John's, Newfoundland A1B 3X7 (Canada); Sutherland, Bruce R., E-mail: bsuther@ualberta.ca [Departments of Physics and Earth and Atmospheric Sciences, University of Alberta, Edmonton, Alberta T6G 2R3 (Canada)

    2014-09-15

    We examine mixed-layer deepening and the generation of internal waves in stratified fluid resulting from turbulence that develops in response to an applied surface stress. In laboratory experiments the stress is applied over the breadth of a finite-length tank by a moving roughened conveyor belt. The turbulence in the shear layer is characterized using particle image velocimetry to measure the kinetic energy density. The internal waves are measured using synthetic schlieren to determine their amplitudes, frequencies, and energy density. We also perform fully nonlinear numerical simulations restricted to two dimensions but in a horizontally periodic domain. These clearly demonstrate that internal waves are generated by transient eddies at the integral length scale of turbulence and which translate with the background shear along the base of the mixed layer. In both experiments and simulations we find that the energy density of the generated waves is 1%–3% of the turbulent kinetic energy density of the turbulent layer.

  11. Internal wave energy radiated from a turbulent mixed layer

    NASA Astrophysics Data System (ADS)

    Munroe, James R.; Sutherland, Bruce R.

    2014-09-01

    We examine mixed-layer deepening and the generation of internal waves in stratified fluid resulting from turbulence that develops in response to an applied surface stress. In laboratory experiments the stress is applied over the breadth of a finite-length tank by a moving roughened conveyor belt. The turbulence in the shear layer is characterized using particle image velocimetry to measure the kinetic energy density. The internal waves are measured using synthetic schlieren to determine their amplitudes, frequencies, and energy density. We also perform fully nonlinear numerical simulations restricted to two dimensions but in a horizontally periodic domain. These clearly demonstrate that internal waves are generated by transient eddies at the integral length scale of turbulence and which translate with the background shear along the base of the mixed layer. In both experiments and simulations we find that the energy density of the generated waves is 1%-3% of the turbulent kinetic energy density of the turbulent layer.

  12. Optimal Power Allocation for Renewable Energy Source

    E-print Network

    Sinha, Abhinav

    2011-01-01

    Battery powered transmitters face energy constraint, replenishing their energy by a renewable energy source (like solar or wind power) can lead to longer lifetime. We consider here the problem of finding the optimal power allocation under random channel conditions for a wireless transmitter, such that rate of information transfer is maximized. Here a rechargeable battery, which is periodically charged by renewable source, is used to power the transmitter. All of above is formulated as a Markov Decision Process. Structural properties like the monotonicity of the optimal value and policy derived in this paper will be of vital importance in understanding the kind of algorithms and approximations needed in real-life scenarios. The effect of curse of dimensionality which is prevalent in Dynamic programming problems can thus be reduced. We show our results under the most general of assumptions.

  13. Onshore wave energy resource: Methodology and tools for the assessment

    SciTech Connect

    Pontes, M.T. [INETI/ITE, Lisbon (Portugal). Dept. of Renewable Energies

    1995-12-31

    The assessment of onshore wave energy resource should in general be based on computational shallow water wave models. The paper summarizes the variety of such models and indicates their merit for different coastal situations and type of study. Case studies for Ireland and Azores islands, Portugal, are presented. The present paper is focused on the evaluation of the onshore wave energy resource. A review of the shallow water phenomena regarding their role in the transformation of the resource as the waves approach the coastline is presented. Since several approaches were developed for predicting computationally the transformation waves undergo in shallow waters, the types of available models are summarized and their applicability to different coastal situations is outlined.

  14. Methodology for evaluation of European wave energy resource

    SciTech Connect

    Pontes, T. [Inst. Nacional de Engenharia e Tecnologia Industrial, Lisbon (Portugal). Dept. of Renewable Energies

    1994-12-31

    This paper presents the work performed in order to establish a common methodology for evaluation of the European offshore as well as shoreline wave energy resource. It includes a review (1) on the background theory of ocean waves that is required to deal with resource evaluation, (2) on the phenomena involved in and the methods used to calculate the transformation that waves undergo as they approach the coastline through waters of decreasing depth as well as (3) on the adequate wave data available in Europe. A methodology (proposed to and accepted by the European Community) for the assessment of the European wave energy resource is described. Further research and development work in this field is identified.

  15. Susceptibility of CMOS IC Devices Under Narrow-Band High Power Electromagnetic Waves by Magnetron

    Microsoft Academic Search

    J. I. Hong; S. M. Hwang; C. S. Huh

    2009-01-01

    We investigated the damage effects of CMOS IC devices manufactured using three different technologies under narrow-band high power electromagnetic (NB-HPEM) waves by magnetron. The output of NB-HPEM waves was controlled from 0 to 1 kW, and the narrow-band operating frequency was 2, 460±50 MHz. The NB-HPEM waves were propagated into a closed-ended standard rectangular waveguide for 1 s. During our

  16. Breezy Power: From Wind to Energy

    ERIC Educational Resources Information Center

    Claymier, Bob

    2009-01-01

    This lesson combines the science concepts of renewable energy and producing electricity with the technology concepts of design, constraints, and technology's impact on the environment. Over five class periods, sixth-grade students "work" for a fictitious power company as they research wind as an alternative energy source and design and test a…

  17. The Rhodotron, a new high-energy, high-power, CW electron accelerator

    Microsoft Academic Search

    Y. Jongen; M. Abs; J. M. Capdevila; D. Defrise; F. Genin; A. Nguyen

    1994-01-01

    Over the last years, a new kind of industrial electron accelerator has been conjointly developed by the French Atomic Energy Agency (CEA) and IBA (Ion Beam Applications) in Belgium. This accelerator, called the Rhodotron, is a recirculating accelerator, operated in CW. It uses low frequencies (metric waves), that make possible the generation of continuous high-energy high-power beams. The construction of

  18. The wells air turbine for wave energy conversion

    Microsoft Academic Search

    S. Raghunathan

    1995-01-01

    The wave energy devices currently in operation in the United Kingdom and India and those that are to be built in Europe are based on the principle of the oscillating water-air column. In these devices the pneumatic energy of the oscillating air column is converted to mechanical energy of rotation by a Wells turbine. A monoplane (single plane) Wells turbine

  19. High power, high efficiency millimeter wavelength traveling wave tubes for high rate communications from deep space

    Microsoft Academic Search

    James A. Dayton Jr.

    1991-01-01

    The high-power transmitters needed for high data rate communications from deep space will require a new class of compact, high efficiency traveling wave tubes (TWT's). Many of the recent TWT developments in the microwave frequency range are generically applicable to mm wave devices, in particular much of the technology of computer aided design, cathodes, and multistage depressed collectors. However, because

  20. Effect of energy storage on variations in wind power

    Microsoft Academic Search

    Jukka V. Paatero; Peter D. Lund

    2005-01-01

    Irregularities in power output are characteristic of intermittent energy, sources such as wind energy, affecting both the power quality and planning of the energy system. In this work the effects of energy storage to reduce wind power fluctuations are investigated. Integration of the energy storage with wind power is modelled using a filter approach in which a time constant corresponds

  1. Equilibrium shoreline response of a high wave energy beach

    USGS Publications Warehouse

    Yates, M.L.; Guza, R.T.; O'Reilly, W. C.; Hansen, J.E.; Barnard, P.L.

    2011-01-01

    Four years of beach elevation surveys at Ocean Beach, San Francisco, California, are used to extend an existing equilibrium shoreline change model, previously calibrated with fine sand and moderate energy waves, to medium sand and higher-energy waves. The shoreline, characterized as the cross-shore location of the mean high water contour, varied seasonally by between 30 and 60 m, depending on the alongshore location. The equilibrium shoreline change model relates the rate of horizontal shoreline displacement to the hourly wave energy E and the wave energy disequilibrium, the difference between E and the equilibrium wave energy that would cause no change in the present shoreline location. Values for the model shoreline response coefficients are tuned to fit the observations in 500 m alongshore segments and averaged over segments where the model has good skill and the estimated effects of neglected alongshore sediment transport are relatively small. Using these representative response coefficients for 0.3 mm sand from Ocean Beach and driving the model with much lower-energy winter waves observed at San Onofre Beach (also 0.3 mm sand) in southern California, qualitatively reproduces the small seasonal shoreline fluctuations at San Onofre. This consistency suggests that the shoreline model response coefficients depend on grain size and may be constant, and thus transportable, between sites with similar grain size and different wave climates. The calibrated model response coefficients predict that for equal fluctuations in wave energy, changes in shoreline location on a medium-grained (0.3 mm) beach are much smaller than on a previously studied fine-grained (0.2 mm) beach. Copyright ?? 2011 by the American Geophysical Union.

  2. Energy Servers Deliver Clean, Affordable Power

    NASA Technical Reports Server (NTRS)

    2010-01-01

    K.R. Sridhar developed a fuel cell device for Ames Research Center, that could use solar power to split water into oxygen for breathing and hydrogen for fuel on Mars. Sridhar saw the potential of the technology, when reversed, to create clean energy on Earth. He founded Bloom Energy, of Sunnyvale, California, to advance the technology. Today, the Bloom Energy Server is providing cost-effective, environmentally friendly energy to a host of companies such as eBay, Google, and The Coca-Cola Company. Bloom's NASA-derived Energy Servers generate energy that is about 67-percent cleaner than a typical coal-fired power plant when using fossil fuels and 100-percent cleaner with renewable fuels.

  3. Enhanced frequency agility of high-power relativistic backward wave oscillators

    Microsoft Academic Search

    L. D. Moreland; E. Schamiloglu; R. W. Lemke; A. M. Roitman; S. D. Korovin; V.V. Rostov

    1996-01-01

    This paper describes how finite length effects in high-power backward wave oscillators can be exploited in a controlled manner to achieve enhanced frequency agility. Experiments were performed using a Sinus-6 high-power relativistic repetitively pulsed electron beam accelerator. A uniform slow wave structure was used in these studies and its parameters were fixed. Sections of smooth-walled circular waveguide of varying lengths

  4. Travelling wave fault location in power transmission lines using statistic data analysis methods

    NASA Astrophysics Data System (ADS)

    Lachugin, V. F.; Panfilov, D. I.; Smirnov, A. N.

    2014-12-01

    A method used for determination of the distance to the location of a fault in a power transmission line is considered. The method is based on separation of traveling waves upon a short circuit and use of statistic analysis methods for determination of the wave front. The efficiency of the proposed method is verified using a mathematical model of a power transmission line. The results of testing the devices for implementation of the proposed method for fault location are cited.

  5. Grating formation by a high power radio wave in near-equator ionosphere

    SciTech Connect

    Singh, Rohtash; Sharma, A. K.; Tripathi, V. K. [Department of Physics, Indian Institute of Technology Delhi, New Delhi-110016 (India)

    2011-11-15

    The formation of a volume grating in the near-equator regions of ionosphere due to a high power radio wave is investigated. The radio wave, launched from a ground based transmitter, forms a standing wave pattern below the critical layer, heating the electrons in a space periodic manner. The thermal conduction along the magnetic lines of force inhibits the rise in electron temperature, limiting the efficacy of heating to within a latitude of few degrees around the equator. The space periodic electron partial pressure leads to ambipolar diffusion creating a space periodic density ripple with wave vector along the vertical. Such a volume grating is effective to cause strong reflection of radio waves at a frequency one order of magnitude higher than the maximum plasma frequency in the ionosphere. Linearly mode converted plasma wave could scatter even higher frequency radio waves.

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

    DOEpatents

    Koplow, Jeffrey P. (San Ramon, CA)

    2012-07-03

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

  7. Energy storage options for space power

    NASA Astrophysics Data System (ADS)

    Hoffman, H. W.; Martin, J. F.; Olszewski, M.

    Including energy storage in a space power supply enhances the feasibility of using thermal power cycles (Rankine or Brayton) and providing high-power pulses. Superconducting magnets, capacitors, electrochemical batteries, thermal phase-change materials (PCM), and flywheels are assessed; the results obtained suggest that flywheels and phase-change devices hold the most promise. Latent heat storage using inorganic salts and metallic eutectics offers thermal energy storage densities of 1500 kJ/kg to 2000 kJ/kg at temperatures to 1675 K. Innovative techniques allow these media to operate in direct contact with the heat engine working fluid. Enhancing thermal conductivity and/or modifying PCM crystallization habit provide other options. Flywheels of low-strain graphite and Kevlar fibers have achieved mechanical energy storage densities of 300 kJ/kg. With high-strain graphite fibers, storage densities appropriate to space power needs (about 500 kJ/kg) seem feasible. Coupling advanced flywheels with emerging high power density homopolar generators and compulsators could result in electric pulse-power storage modules of significantly higher energy density.

  8. InGaAs pseudomorphic HEMTs for millimeter wave power applications

    Microsoft Academic Search

    P. M. Smith; P. C. Chao; L. F. Lester; R. P. Smith; B. R. Lee; D. W. Ferguson; A. A. Jabra; J. M. Ballingall; K. H. G. Duh

    1988-01-01

    The development of InGaAs pseudomorphic high-electron mobility transistors (HEMTs) with state-of-the-art power performance at millimeter-wave frequencies is reported. Results given include maximum power-added efficiencies of 44% at 35 GHz and 36% at 44 GHz, output power of 100 mW with 22% efficiency and 3-dB gain at 60 GHz, and output power of 9 mW at 94 GHz. Preliminary reliability data

  9. CVD diamond windows studied with low- and high-power millimeter waves

    Microsoft Academic Search

    Roland Heidinger; Günter Dammertz; Andreas Meier; Manfred K. Thumm

    2002-01-01

    As part of long-pulse high-power gyrotron development low- and high-power millimeter-wave characterization has been performed on bare and brazed chemical vapor deposition (CVD) diamond disks. The dielectric property measurements performed with low-power open resonator studies demonstrate the availability of large area CVD diamond disks fulfilling the requirements for high-power windows. In brazed components, additional surface losses are put to evidence.

  10. Antisymmetric Wave Functions for Mixed Fermion States and Energy Convexity

    SciTech Connect

    Gonis, Antonios [ORNL; Zhang, Xiaoguang [ORNL; Nicholson, Don M [ORNL; Stocks, George Malcolm [ORNL

    2011-01-01

    We develop the formal basis for the study of independent collections of internally interacting many-particle systems, defined as systems associated with non-overlapping coordinate spaces. We show how ensembles or mixed states of independent many-Fermion systems in their ground states can be described by pure states and give rise to wave functions that are antisymmetric with respect to interchange of particle coordinates (and spin). This is achieved by defining an ensemble Hilbert space whose coordinate representation consists of the tensor sum, rather than product, of the coordinates of the systems in the ensemble. As a demonstration of the power of this new formalism, and under the assumptions of a positive interparticle interaction and a corresponding energy that is extensive in the number of particle pairs (pair extensive), we prove the convexity relation, $E_v[N-1]+E_v[N+1]\\ge 2E_v[N]$, where $E_v[N]$ denotes the total ground state energy of $N$ electrons under an external potential, $v({\\bf r})$.

  11. 'People Power' Saves Plant Energy 

    E-print Network

    Davidson, B. G., Jr.; Kanewske, F. J.

    1981-01-01

    burner air registers ? Poor burner performance ? Leaking flue gas and draft sample lines ? Air leaks into firebox ? Refractory damage If inspections are not made until heaters are shut down, many of the above items will be hard to detect... and compressed air leaks, faulty insulation, incorrect drivers in service, and faulty burner adjustment on fired heaters ? Visits to "talk up" energy conservation with the foremen and operators These engineers also monitor the operation of several on...

  12. Advances in the understanding of efficient operation of high power backward-wave oscillators

    Microsoft Academic Search

    E. Schamiloglu; L. D. Moreland; R. W. Lemke

    1995-01-01

    Summary form only given. Recent work has shown that the efficiency of converting electron beam energy to microwave energy in a backward wave oscillator (BWO) depends very strongly on reflections within the slow wave structure (SWS), and on the interaction of the electron beam with the forward travelling harmonics. The latter result differs from earlier work where it was indicated

  13. Multi-ion-species effects on magnetosonic waves and energy transfer in thermal equilibrium plasmas

    E-print Network

    Toida, M; Ohsawa, Y; Toida, Mieko; Yoshiya, Takashi; Ohsawa, Yukiharu

    2004-01-01

    Magnetosonic waves propagating perpendicular to an external magnetic field are studied with attention to the effect of multiple ion species. First, power spectra of magnetic field fluctuations and autocorrelation functions in thermal equilibrium plasmas are numerically obtained. In a multi-ion-species plasma, besides $\\omega \\simeq kv_{\\rm A}$ mode, numerous waves are present near many different ion cyclotron frequencies. The autocorrelation function of the quasi-mode consisting of these waves is not recovered to its initial value, owing to the phase mixing of these waves. Next, with particle simulations, evolution of a macroscopic perpendicular disturbance is investigated. In a multi-ion-species plasma, this disturbance is damped. The energy is transferred to from the magnetic field to the ions.

  14. Damping Pressure Pulsations in a Wave-Powered Desalination System

    E-print Network

    Padhye, Nikhil

    Wave-driven reverse osmosis desalination systems can be a cost-effective option for providing a safe and reliable source of drinking water for large coastal communities. Such systems usually require the stabilization of ...

  15. A resonant two body system for a point absorbing wave energy converter with direct-driven linear generator

    NASA Astrophysics Data System (ADS)

    Engström, J.; Kurupath, V.; Isberg, J.; Leijon, M.

    2011-12-01

    Based on an earlier conceptual model of a two body system point absorbing wave energy converter tuned to resonance in Swedish west coast sea states, an extended coupled hydrodynamic, mechanic, and electromagnetic model has been developed. The hydrodynamic characteristics of the two body system are studied in the frequency and time domain, while its response to real Swedish west coast sea states are studied in the time domain, by using a wave energy converter model with two independently moving bodies connected to a direct driven linear generator with non-linear damping. The two body system wave energy converter gives nearly 80% power capture ratio in irregular waves. The resonant behaviour is shown to be sensitive to the shape of the spectrum, and the distance between the two bodies is shown to have a large effect on the power absorption.

  16. An electrical approach to wave energy conversion

    Microsoft Academic Search

    M. Leijon; O. Danielsson; M. Eriksson; K. Thorburn; H. Bernhoff; J. Isberg; J. Sundberg; I. Ivanova; E. Sjöstedt; O. Ågren; K. E. Karlsson; A. Wolfbrandt

    2006-01-01

    Motions in nature, for example ocean waves, can play a significant role in tomorrow's electricity production, but the constructions require adaptations to its media. Engineers planning hydropower plants have always taken natural conditions, such as fall height, speed of flow, and geometry, as basic design parameters and constraints in the design. The present paper describes a novel approach for electric

  17. Wave energy resources in sheltered sea areas: A case study of the Baltic Sea

    Microsoft Academic Search

    Hans Bernhoff; Elisabeth Sjöstedt; Mats Leijon

    2006-01-01

    Wave energy is a renewable source, which has not yet been exploited to a large extent. So far the main focus of wave energy conversion has been on the large wave energy resources of the great oceans on northern latitudes. However, large portions of the world potential wave energy resources are found in sheltered waters and calmer seas, which often

  18. Power management for energy harvesting wireless sensors

    NASA Astrophysics Data System (ADS)

    Arms, S. W.; Townsend, C. P.; Churchill, D. L.; Galbreath, J. H.; Mundell, S. W.

    2005-05-01

    The objective of this work was to demonstrate smart wireless sensing nodes capable of operation at extremely low power levels. These systems were designed to be compatible with energy harvesting systems using piezoelectric materials and/or solar cells. The wireless sensing nodes included a microprocessor, on-board memory, sensing means (1000 ohm foil strain gauge), sensor signal conditioning, 2.4 GHz IEEE 802.15.4 radio transceiver, and rechargeable battery. Extremely low power consumption sleep currents combined with periodic, timed wake-up was used to minimize the average power consumption. Furthermore, we deployed pulsed sensor excitation and microprocessor power control of the signal conditioning elements to minimize the sensors" average contribution to power draw. By sleeping in between samples, we were able to demonstrate extremely low average power consumption. At 10 Hz, current consumption was 300 microamps at 3 VDC (900 microwatts); at 5 Hz: 400 microwatts, at 1 Hz: 90 microwatts. When the RF stage was not used, but data were logged to memory, consumption was further reduced. Piezoelectric strain energy harvesting systems delivered ~2000 microwatts under low level vibration conditions. Output power levels were also measured from two miniature solar cells; which provided a wide range of output power (~100 to 1400 microwatts), depending on the light type & distance from the source. In summary, system power consumption may be reduced by: 1) removing the load from the energy harvesting & storage elements while charging, 2) by using sleep modes in between samples, 3) pulsing excitation to the sensing and signal conditioning elements in between samples, and 4) by recording and/or averaging, rather than frequently transmitting, sensor data.

  19. Power management solutions for energy management, power quality and environment using battery energy storage systems

    Microsoft Academic Search

    D. Sutanto

    1999-01-01

    Summary form only as given. The emergency of new breeds of power electronics and improved battery technology has created renewed interests in battery energy storage system (BESS). BESS is a modern cost-effective solution that can help both electric utilities and industrial and commercial businesses to meet the growing need of controlling peak energy usage, power quality and environmental problems. BESS

  20. Power smoothing and power ramp control for wind energy using energy storage

    Microsoft Academic Search

    Ali Esmaili; Adel Nasiri

    2011-01-01

    Due to randomness of wind speed, the wind farm output power varies drastically. These fluctuations make undesirable effects on the voltage, frequency, and transient stability of the utility grid. In this paper, two types of energy storage devices are integrated with a wind farm to support the short-term shortcomings of wind energy. The support specifically improves power ramp rate control

  1. Non-classical Energy Conservation in Multi-wave Systems: "Extra Energy", "Negative Energy" and "Annihilation of Energy"

    E-print Network

    S. V. Kukhlevsky

    2013-01-17

    The energy conservation is a general law of nature. In the classical physics, the energy W_{AB} of a conservative system {AB} that contains the objects A and B is equal to a sum of the positive energies W_A and W_B of the isolated objects A and B, W_{AB} = W_A+W_B. We show that the energy conservation does not exhibit the "classic law" if the physical objects are waves or they do have a wave nature of microscopic (quantum) objects. The "extra energy", "negative energy" and "annihilation of energy" are predicted for multi-wave (multi-beam) systems. The paradoxical phenomenon is demonstrated in context of the extraordinary transmission of light and matter through subwavelength aperture arrays assisted by surface waves [T.W. Ebbesen et al., Nature (London) 391, 667(1998)) and E. Moreno et al., Phys. Rev. Lett. 95, 170406 (2005)].

  2. Energy prediction of Amonix solar power plants

    NASA Astrophysics Data System (ADS)

    Kinsey, Geoffrey S.; Stone, Kenneth; Garboushian, Vahan

    2010-08-01

    Amonix has installed over 300 kW of systems using III-V multijunction cells. The Amonix 7500 Solar Power Generator, rated at 38 kWAC, generated over 90 MW-hr during its first twelve months of operation. A model of system performance using a meteorological database and applying the effects of losses in the optical and power paths predicted field performance to within 1% after twelve months of operation. The energy yield of power plants employing Amonix systems is expected to exceed 2700 kW-hr/kW. Systems installed in 2010 are expected to deliver a 10% increase in performance.

  3. Vector Finite Element Modeling of the Full-Wave Maxwell Equations to Evaluate Power Loss in Bent Optical Fibers

    SciTech Connect

    Koning, J; Rieben, R; Rodrigue, G

    2004-12-09

    We measure the loss of power incurred by the bending of a single mode step-indexed optical fiber using vector finite element modeling of the full-wave Maxwell equations in the optical regime. We demonstrate fewer grid elements can be used to model light transmission in longer fiber lengths by using high-order basis functions in conjunction with a high order energy conserving time integration method. The power in the core is measured at several points to determine the percentage loss. We also demonstrate the effect of bending on the light polarization.

  4. Kinetics of density striations excited by powerful electromagnetic waves in the ionosphere

    SciTech Connect

    Istomin, Ya. N. [P. N. Lebedev Physical Institute, Leninsky Prospect 53, 117924 Moscow (Russian Federation); Leyser, T. B. [Swedish Institute of Space Physics, Box 537, SE-751 21 Uppsala (Sweden)

    2010-03-15

    One of the most important effects observed when pumping ionospheric plasma by powerful radio waves from the ground is the excitation of filamentary density striations that are stretched along the ambient geomagnetic field. The kinetics of the striations present in the pump electromagnetic field is studied theoretically. The density irregularities cause inhomogeneities in the pump field, which result in a ponderomotive force acting on the striations that makes the density depressions move perpendicular to the geomagnetic field. Striations moving with different velocities can collide, thereby merging to produce larger scale striations. The merging of striations constitutes a cascade process that distributes the energy over the spatial spectrum of the striations. The resulting inhomogeneity spectrum as well as the obtained outward radial drift of a few meters per second is consistent with experimental results.

  5. Enhanced frequency agility of high-power relativistic backward wave oscillators

    SciTech Connect

    Moreland, L.D.; Schamiloglu, E. [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Electrical and Computer Engineering] [Univ. of New Mexico, Albuquerque, NM (United States). Dept. of Electrical and Computer Engineering; Lemke, R.W. [Sandia National Labs., Albuquerque, NM (United States)] [Sandia National Labs., Albuquerque, NM (United States); Roitman, A.M.; Korovin, S.D.; Rostov, V.V. [Russian Academy of Sciences, Tomsk (Russian Federation). High Current Electronics Inst.] [Russian Academy of Sciences, Tomsk (Russian Federation). High Current Electronics Inst.

    1996-06-01

    This paper describes how finite length effects in high-power backward wave oscillators can be exploited in a controlled manner to achieve enhanced frequency agility. Experiments were performed using a Sinus-6 high-power relativistic repetitively pulsed electron beam accelerator. A uniform slow wave structure was used in these studies and its parameters were fixed. Sections of smooth-walled circular waveguide of varying lengths were inserted both before and after the slow wave structure. Variations in the length of smooth-walled waveguide on the order of a quarter-wavelength of the generated electromagnetic radiation were found to significantly affect both microwave frequency and radiation efficiency in a periodic-like manner. The experimental results were reproduced in TWOQUICK electromagnetic particle-in-cell simulations. A bandwidth of about 500 MHz centered around 9.5 GHz at hundreds of MW power levels has been achieved with constant beam and slow wave structure parameters.

  6. High-energy effective action from scattering of QCD shock waves

    SciTech Connect

    Ian Balitsky

    2005-10-25

    At high energies, the relevant degrees of freedom are Wilson lines--infinite gauge links ordered along straight lines collinear to the velocities of colliding particles. The effective action for these Wilson lines is determined by the scattering of QCD shock waves. I develop the symmetric expansion of the effective action in powers of strength of one of the shock waves and calculate the leading term of the series. The corresponding first-order effective action, symmetric with respect to the projectile and target, includes both up and down fan diagrams and pomeron loops.

  7. High-energy effective action from scattering of QCD shock waves

    SciTech Connect

    Ian Balitsky

    2005-05-15

    At high energies, the relevant degrees of freedom are Wilson lines - infinite gauge links ordered along straight lines collinear to the velocities of colliding particles. The effective action for these Wilson lines is determined by the scattering of QCD shock waves. I develop the symmetric expansion of the effective action in powers of strength of one of the shock waves and calculate the leading term of the series. The corresponding first-order effective action, symmetric with respect to projectile and target, includes both up and down fan diagrams and pomeron loops.

  8. The energy of high frequency waves in the low solar Chromosphere

    E-print Network

    Aleksandra Andic

    2007-03-28

    High frequency acoustic waves have been suggested as a source of mechanical heating in the chromosphere. In this work the radial component of waves in the frequency interval 22mHz to 1mHz are investigated. Observations were performed using 2D spectroscopy in the spectral lines of Fe I 543.45nm and Fe I 543.29nm at the Vacuum Tower Telescope, Tenerife, Spain. Speckle reconstruction has been applied to the observations. We have used Fourier and wavelet techniques to identify oscillatory power. The energy flux is estimated assuming that all observed oscillations are acoustics running waves. We find that the estimated energy flux is not sufficient to cover the chromospheric radiative losses.

  9. Energy saving potential of office equipment power management

    Microsoft Academic Search

    Kaoru Kawamoto; Yoshiyuki Shimoda; Minoru Mizuno

    2004-01-01

    While many studies have estimated the energy saving potential of office equipment power management, there is no recent study about the energy saving potential of shortening the power management delay time. In this paper, we estimated the energy saving potential of the complete saturation of power management, and also the additional energy saving potential of shortening the power management delay

  10. Low power energy harvesting and storage techniques from ambient human powered energy sources

    NASA Astrophysics Data System (ADS)

    Yildiz, Faruk

    Conventional electrochemical batteries power most of the portable and wireless electronic devices that are operated by electric power. In the past few years, electrochemical batteries and energy storage devices have improved significantly. However, this progress has not been able to keep up with the development of microprocessors, memory storage, and sensors of electronic applications. Battery weight, lifespan and reliability often limit the abilities and the range of such applications of battery powered devices. These conventional devices were designed to be powered with batteries as required, but did not allow scavenging of ambient energy as a power source. In contrast, development in wireless technology and other electronic components are constantly reducing the power and energy needed by many applications. If energy requirements of electronic components decline reasonably, then ambient energy scavenging and conversion could become a viable source of power for many applications. Ambient energy sources can be then considered and used to replace batteries in some electronic applications, to minimize product maintenance and operating cost. The potential ability to satisfy overall power and energy requirements of an application using ambient energy can eliminate some constraints related to conventional power supplies. Also power scavenging may enable electronic devices to be completely self-sustaining so that battery maintenance can eventually be eliminated. Furthermore, ambient energy scavenging could extend the performance and the lifetime of the MEMS (Micro electromechanical systems) and portable electronic devices. These possibilities show that it is important to examine the effectiveness of ambient energy as a source of power. Until recently, only little use has been made of ambient energy resources, especially for wireless networks and portable power devices. Recently, researchers have performed several studies in alternative energy sources that could provide small amounts of electricity to low-power electronic devices. These studies were focused to investigate and obtain power from different energy sources, such as vibration, light, sound, airflow, heat, waste mechanical energy and temperature variations. This research studied forms of ambient energy sources such as waste mechanical (rotational) energy from hydraulic door closers, and fitness exercise bicycles, and its conversion and storage into usable electrical energy. In both of these examples of applications, hydraulic door closers and fitness exercise bicycles, human presence is required. A person has to open the door in order for the hydraulic door closer mechanism to function. Fitness exercise bicycles need somebody to cycle the pedals to generate electricity (while burning calories.) Also vibrations, body motions, and compressions from human interactions were studied using small piezoelectric fiber composites which are capable of recovering waste mechanical energy and converting it to useful electrical energy. Based on ambient energy sources, electrical energy conversion and storage circuits were designed and tested for low power electronic applications. These sources were characterized according to energy harvesting (scavenging) methods, and power and energy density. At the end of the study, the ambient energy sources were matched with possible electronic applications as a viable energy source.

  11. Local energy decay for linear wave equations with variable coefficients

    NASA Astrophysics Data System (ADS)

    Ikehata, Ryo

    2005-06-01

    A uniform local energy decay result is derived to the linear wave equation with spatial variable coefficients. We deal with this equation in an exterior domain with a star-shaped complement. Our advantage is that we do not assume any compactness of the support on the initial data, and its proof is quite simple. This generalizes a previous famous result due to Morawetz [The decay of solutions of the exterior initial-boundary value problem for the wave equation, Comm. Pure Appl. Math. 14 (1961) 561-568]. In order to prove local energy decay, we mainly apply two types of ideas due to Ikehata-Matsuyama [L2-behaviour of solutions to the linear heat and wave equations in exterior domains, Sci. Math. Japon. 55 (2002) 33-42] and Todorova-Yordanov [Critical exponent for a nonlinear wave equation with damping, J. Differential Equations 174 (2001) 464-489].

  12. Energy Dissipation when Internal Wave Beams Reflect from a Slope

    NASA Astrophysics Data System (ADS)

    Rodenborn, Bruce; Kiefer, Daniel; Zhang, Hepeng; Swinney, Harry L.

    2015-03-01

    Internal wave reflection from a uniform sloping boundary is often analyzed using linear or a weakly nonlinear inviscid theory. Under these assumptions for a linearly stratified fluid, Thorpe and Tabaei et al. derived predictions for the boundary angle where second harmonic generation should be most intense. We previously conducted experiments and simulations that found the angle that maximizes second harmonic generation is given instead by an empirical geometric relationship between the wave beam and boundary angles. In the previous study, we used integrated kinetic energy as a measure of beam intensity. We compare these results with a method using energy flux. We also study the energy flux into and out of a surface above the reflection region Eout /Ein and find high rates of energy dissipation O(90%). The rates remain high even for weakly nonlinear wave beams and with the viscosity reduced by an order of magnitude. S. A. Thorpe, J. Fluid Mech., 178, 279-302 (1987)

  13. The study of waves is clearly an important subject in acoustics because sound energy is transmitted by waves traveling though air. Furthermore, it turns out that the

    E-print Network

    Robertson, William

    Waves The study of waves is clearly an important subject in acoustics because sound energy, wavelength and speed of all types of waves, not only sound. In the case of sound waves in air the wave speed is transmitted by waves traveling though air. Furthermore, it turns out that the properties of waves on strings

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

    NASA Astrophysics Data System (ADS)

    Minor, Quinn E.; Kaplinghat, Manoj

    2015-03-01

    We point out three correlated predictions of the axion monodromy inflation model: the large amplitude of gravitational waves, the suppression of power on horizon scales and on scales relevant for the formation of dwarf galaxies. While these predictions are likely generic to models with oscillations in the inflaton potential, the axion monodromy model naturally accommodates the required running spectral index through Planck-scale corrections to the inflaton potential. Applying this model to a combined data set of Planck, ACT, SPT, and WMAP low-? polarization cosmic microwave background (CMB) data, we find a best-fit tensor-to-scalar ratio r0.05=0.07-0.04+0.05 due to gravitational waves, which may have been observed by the BICEP2 experiment. Despite the contribution of gravitational waves, the total power on large scales (CMB power spectrum at low multipoles) is lower than the standard ? CDM cosmology with a power-law spectrum of initial perturbations and no gravitational waves, thus mitigating some of the tension on large scales. There is also a reduction in the matter power spectrum of 20-30% at scales corresponding to k =10 Mpc-1 , which are relevant for dwarf galaxy formation. This will alleviate some of the unsolved small-scale structure problems in the standard ? CDM cosmology. The inferred matter power spectrum is also found to be consistent with recent Lyman-? forest data, which is in tension with the Planck-favored ? CDM model with a power-law primordial power spectrum.

  15. Development of a medium power L-band traveling-wave amplifier

    Microsoft Academic Search

    L. W. Holmboe; M. Ettenberg

    1957-01-01

    The development and performance of a high gain medium power traveling-wave amplifier are described. Powers up to 7 watts at 15 per cent efficiency have been achieved. The small signal gain approaches 50 db in the middle of the band, and exceeds 35 db over a 2 to 1 range of frequencies. The tube itself consists of a glass-supported helix

  16. Development of a medium power L-band traveling-wave amplifier

    Microsoft Academic Search

    L. W. Holmboe; M. Ettenberg

    1955-01-01

    The development and performance of a high gain medium power traveling wave amplifier are described. Powers up to 7 watts at 15% efficiency have been achieved. The small signal gain approaches 50 db in the middle of the band, and exceeds 35 db over a 2 to 1 range of frequencies. The tube itself consists of a glass supported helix

  17. Energy of tsunami waves generated by bottom motion

    E-print Network

    Boyer, Edmond

    Energy of tsunami waves generated by bottom motion By Denys Dutykh, Fr´ed´eric Dias CMLA, ENS literature on tsunami research, few articles have been devoted to en- ergy issues. A theoretical at higher order in the energy budget. Then we solve the Cauchy­Poisson problem of tsunami generation

  18. MATHEMATICAL ANALYSIS OF A WAVE ENERGY CONVERTER ARNAUD ROUGIREL

    E-print Network

    Paris-Sud XI, Université de

    MATHEMATICAL ANALYSIS OF A WAVE ENERGY CONVERTER MODEL ARNAUD ROUGIREL Abstract. In a context where energy converter without mass modulation. 1. Introduction In the recent years, sustainable development sustainable development should be a priority, Orazov et al. have proposed in 2010, an excitation scheme

  19. Energy Preserving Schemes for Nonlinear Hamiltonian Systems of Wave Equations.

    E-print Network

    Paris-Sud XI, Université de

    Energy Preserving Schemes for Nonlinear Hamiltonian Systems of Wave Equations. Application on the mathematical study of these systems, showing central properties (energy preservation, stability, hyperbolicity of "preserving schemes" is introduced, and we show that explicit schemes or partially implicit schemes which

  20. Mechanisms of ignition by transient energy deposition: Regimes of combustion wave propagation

    NASA Astrophysics Data System (ADS)

    Kiverin, A. D.; Kassoy, D. R.; Ivanov, M. F.; Liberman, M. A.

    2013-03-01

    Regimes of chemical reaction wave propagating in reactive gaseous mixtures, whose chemistry is governed by chain-branching kinetics, are studied depending on the characteristics of a transient thermal energy deposition localized in a finite volume of reactive gas. Different regimes of the reaction wave propagation are initiated depending on the amount of deposited thermal energy, power of the source, and the size of the hot spot. The main parameters which define regimes of the combustion waves facilitated by the transient deposition of thermal energy are acoustic time scale, duration of the energy deposition, ignition time scale, and size of the hot spot. The interplay between these parameters specifies the role of gasdynamical processes, the formation and steepness of the temperature gradient, and speed of the spontaneous wave. The obtained results show how ignition of one or another combustion regime depends on the value of energy, rate of the energy deposition, and size of the hot spot, which is important for the practical use and for risk assessment.

  1. Energy Partitioning of Seismic Waves in Fractured Rocks

    SciTech Connect

    NONE

    1997-08-31

    Advances in locating and characterizes fractures in oil and gas reservoirs, and at waste isolation sites from seismic surveys requires improved interpretation methods. Experimental and theoretical results from this work have lead to an understanding of diagnostic signatures of energy that is partitioned into body waves and guided modes by fractures. Compressional waves and shear waves (i.e., shear waves with particle motion perpendicular to the fracture plane) are sensitive to changes in shear stress on a pre-existing fracture and to the formation of a fracture in a previously intact specimen. Both types of waves exhibit a shift in frequency content and a change in the amplitude of the wave as a fracture is formed or a pre-existing fracture is closed. The dispersion characteristics of interfact waves that propagate along a fracture enable quantification of fracture specific stiffness. A new compressional-mode interface wave was measured that has the potential for becoming a diagnostic tool for changes in stress in a fracture. The results of this research provide the basis for the development of seismic imaging techniques and analyses tools for locating and characterizing fractures on the field scale.

  2. The oscillating water column wave-energy device

    Microsoft Academic Search

    D. V. Evans

    1978-01-01

    An expression is obtained for the efficiency of wave-energy absorption of a float connected to a spring-dashpot system on the top of a column of fluid bounded by two closely-spaced vertical parallel plates or a narrow tube immersed under waves. The method makes extensive use of the approximate solution using matched asymptotic expansions obtained by Newman (1974) to the corresponding

  3. Method of, and apparatus for, extracting energy from waves

    SciTech Connect

    Laithwaite, E.R.; Salter, S.H.

    1981-11-17

    In a method of, and apparatus for, extracting energy from waves on a liquid, the precession of a gyroscope in response to angular motion of a member in response to waves performs useful work by operating a hydraulic pump. Advantageously, pairs of gyroscopes having their rotors spinning in opposite directions are mounted in the member so as to balance the output torques of the gyroscopes.

  4. Zero Energy of Plane-Waves for ELKOs

    E-print Network

    Luca Fabbri

    2011-02-23

    We consider the ELKO field in interaction through contorsion with its own spin density, and we investigate the form of the consequent autointeractions; to do so we take into account the high-density limit and find plane wave solutions: such plane waves give rise to contorsional autointeractions for which the Ricci metric curvature vanishes and therefore the energy density is equal to zero identically. Consequences are discussed.

  5. Effects of chemical fuel composition on energy generation from thermopower waves

    NASA Astrophysics Data System (ADS)

    Yeo, Taehan; Hwang, Hayoung; Jeong, Dong-Cheol; Lee, Kang Yeol; Hong, Jongsup; Song, Changsik; Choi, Wonjoon

    2014-11-01

    Thermopower waves, which occur during combustion within hybrid structures formed from nanomaterials and chemical fuels, result in a self-propagating thermal reaction and concomitantly generate electrical energy from the acceleration of charge carriers along the nanostructures. The hybrid structures for thermopower waves are composed of two primary components: the core thermoelectric material and the combustible fuel. So far, most studies have focused on investigating various nanomaterials for improving energy generation. Herein, we report that the composition of the chemical fuel used has a significant effect on the power generated by thermopower waves. Hybrid nanostructures consisting of mixtures of picric acid and picramide with sodium azide were synthesized and used to generate thermopower waves. A maximum voltage of ˜2 V and an average peak specific power as high as 15 kW kg?1 were obtained using the picric acid/sodium azide/multiwalled carbon nanotubes (MWCNTs) array composite. The average reaction velocity and the output voltage in the case of the picric acid/sodium azide were 25 cm s?1 and 157 mV, while they were 2 cm s?1 and 3 mV, in the case of the picramide/sodium azide. These marked differences are attributable to the chemical and structural differences of the mixtures. Mixing picric acid and sodium azide in deionized water resulted in the formation of 2,4,6-trinitro sodium phenoxide and hydrogen azide (H-N3), owing to the exchange of H+ and Na+ ions, as well as the formation of fiber-like structures, because of benzene ? stacking. The negative enthalpy of formation of the new compounds and the fiber-like structures accelerate the reaction and increase the output voltage. Elucidating the effects of the composition of the chemical fuel used in the hybrid nanostructures will allow for the control of the combustion process and help optimize the energy generated from thermopower waves, furthering the development of thermopower waves as an energy source.

  6. Effects of chemical fuel composition on energy generation from thermopower waves.

    PubMed

    Yeo, Taehan; Hwang, Hayoung; Jeong, Dong-Cheol; Lee, Kang Yeol; Hong, Jongsup; Song, Changsik; Choi, Wonjoon

    2014-11-01

    Thermopower waves, which occur during combustion within hybrid structures formed from nanomaterials and chemical fuels, result in a self-propagating thermal reaction and concomitantly generate electrical energy from the acceleration of charge carriers along the nanostructures. The hybrid structures for thermopower waves are composed of two primary components: the core thermoelectric material and the combustible fuel. So far, most studies have focused on investigating various nanomaterials for improving energy generation. Herein, we report that the composition of the chemical fuel used has a significant effect on the power generated by thermopower waves. Hybrid nanostructures consisting of mixtures of picric acid and picramide with sodium azide were synthesized and used to generate thermopower waves. A maximum voltage of ?2 V and an average peak specific power as high as 15 kW kg(-1) were obtained using the picric acid/sodium azide/multiwalled carbon nanotubes (MWCNTs) array composite. The average reaction velocity and the output voltage in the case of the picric acid/sodium azide were 25 cm s(-1) and 157 mV, while they were 2 cm s(-1) and 3 mV, in the case of the picramide/sodium azide. These marked differences are attributable to the chemical and structural differences of the mixtures. Mixing picric acid and sodium azide in deionized water resulted in the formation of 2,4,6-trinitro sodium phenoxide and hydrogen azide (H-N3), owing to the exchange of H(+) and Na(+) ions, as well as the formation of fiber-like structures, because of benzene ? stacking. The negative enthalpy of formation of the new compounds and the fiber-like structures accelerate the reaction and increase the output voltage. Elucidating the effects of the composition of the chemical fuel used in the hybrid nanostructures will allow for the control of the combustion process and help optimize the energy generated from thermopower waves, furthering the development of thermopower waves as an energy source. PMID:25319506

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

    E-print Network

    Amer, Ahmed 1979-

    2012-01-23

    harmonic mixer with pre-amplifier and poly-phase generator are presented as a part of a novel millimeter wave dual-band receiver (31/24 GHz) implemented in 0.18 micrometer SiGe BiCMOS technology. Complete receiver measurements show a conversion gain higher...

  8. Latching control of deep water wave energy devices using an active reference

    Microsoft Academic Search

    Umesh A. Korde

    2002-01-01

    This paper investigates latching type control on a floating wave energy converter in deep water. An on-board, actively controlled motion-compensated platform is used as a reference (‘active reference’) for power absorption and latching. A variational formulation is used to evaluate an optimal control sequence in the time domain. Time domain simulation results are presented for a heaving buoy in small-amplitude

  9. Technical Note TN-56 Power and Energy

    E-print Network

    Flinn, Jason

    WRL Technical Note TN-56 Power and Energy Characterization of the Itsy Pocket Computer (Version 1 Alto, California 94301 USA #12;WRL TECHNICAL NOTE TN- 1 Research group. Our focus is research on information technology that is relevant to the technical strategy

  10. Adaptive power management in energy harvesting systems

    Microsoft Academic Search

    Clemens Moser; Lothar Thiele; Davide Brunelli; Luca Benini

    2007-01-01

    Recently, there has been a substantial interest in the de- sign of systems that receive their energy from regenerative sources such as solar cells. In contrast to approaches that attempt to minimize the power consumption we are con- cerned with adapting parameters of the application such that a maximal utility is obtained while respecting the lim- ited and time-varying amount

  11. Tower Power: Producing Fuels from Solar Energy

    ERIC Educational Resources Information Center

    Antal, M. J., Jr.

    1976-01-01

    This article examines the use of power tower technologies for the production of synthetic fuels. This process overcomes the limitations of other processes by using a solar furnace to drive endothermic fuel producing reactions and the resulting fuels serve as a medium for storing solar energy. (BT)

  12. Radiant energy to electrical power conversion system

    Microsoft Academic Search

    Brunson

    1980-01-01

    A radiant energy to electrical power thermionic conversion system is disclosed that uses a transducer structure with very closely spaced cathode and anode elements in a vacuum to minimize space charge buildup and to optimize cross transfer of electrons from cathode to anode. The materials chosen are for a high work function high melt temperature cathode, tungsten for example with

  13. The South Carolina Coastal Erosion Study: Wind Wave Energy Dissipation

    NASA Astrophysics Data System (ADS)

    Demir, H.; Work, P. A.; Voulgaris, G.

    2004-12-01

    As part of the South Carolina Coastal Erosion Study (SCCES) wave and current data were collected offshore of Myrtle Beach, SC for 2 months in 2001-02. This field measurement campaign was the second of a three-part experiment series. While the overall objective of the study is to describe the processes governing the circulation, wave propagation and sediment transport along the northern South Carolina coast, this presentation focuses on the wave energy dissipation over a heterogeneous seafloor over a distance of 6 km. The data were collected between November 9, 2001 and January 17, 2002. The instruments were placed along a transect crossing a large sand shoal in an area otherwise largely deprived of sand, at depths of 8 to 12 meters. The four instruments used, in order of decreasing distance from shore, were 600 and1200 KHz RDI ADCP's, a Nortek Aquadopp and a Sontek Argonaut-XR. Bathymetry and bottom characteristics such as depth and thickness of sand layer are available through USGS's coastal relief model and side scan surveys. Wind data are supplied by a large-scale numerical wind model. Its output is compared with wind data collected at Frying Pan Shoals buoy and at an anemometer placed at Spring Maid pier after the experiment. The SWAN wave model (Booij et al. 1999) was used to model the spectral wave transformation from the offshore buoy to the inner stations and to compare the observed wave energy dissipation to the available models. There was no extreme storm event during the deployment period. The maximum significant wave height observed was 1.6 meters at the offshore wave station, and the mean wave height was 0.8 meters. The mean period was between 5 and 7 seconds most of the time. Significant wave energy dissipation (up to 40% decrease in wave energy flux) across 6 km was observed. A shift of the spectral peak and a change in the spectral shape was observed in many events, which were not generally reproduced by the model. Sand and rock bottom characteristics were modeled with different dissipation coefficients. The coefficients were optimized to give the best fit to the data. Since the dissipation process is non-linear, iterative linear regression techniques were employed. The physical meaning of the coefficients and the improvements achieved with varying bottom friction coefficients are discussed.

  14. ON THE SELF-AVERAGING OF WAVE ENERGY IN RANDOM GUILLAUME BAL

    E-print Network

    Bal, Guillaume

    ON THE SELF-AVERAGING OF WAVE ENERGY IN RANDOM MEDIA GUILLAUME BAL Abstract. We consider the stabilization (self-averaging) and destabilization of the energy of waves propagating in random media transport equations for arbitrary statistical moments of the wave field is used to show that wave energy

  15. Wave Energy Machine Louise Butler, Bilal Demir, Caleb Lee, Joe Meiners, Christian Rodin

    E-print Network

    Provancher, William

    Wave Energy Machine Louise Butler, Bilal Demir, Caleb Lee, Joe Meiners, Christian Rodin Advisor: Dr. Introduction Design Kinematic Model Testing Current wave energy technology harvests the vertical motion. Project Statement: Design a wave energy machine that harnesses underwater wave motion and converts

  16. LABORATORY OBSERVATIONS AND NUMERICAL MODELING OF THE EFFECTS OF AN ARRAY OF WAVE ENERGY CONVERTERS

    E-print Network

    Haller, Merrick

    1 LABORATORY OBSERVATIONS AND NUMERICAL MODELING OF THE EFFECTS OF AN ARRAY OF WAVE ENERGY of wave energy converters (WECs) on water waves through the analysis of extensive laboratory experiments absorption is a reasonable predictor of the effect of WECs on the far field. Keywords: wave- energy; spectral

  17. Local full-wave energy in nonuniform plasmas

    SciTech Connect

    Smithe, D.N.

    1988-10-01

    The subject of local wave energy in plasmas is treated via quasilinear theory from the dual perspectives of the action-angle formalism and gyrokinetics analysis. This work presents an extension to all orders in the gyroradius of the self-consistent wave-propagation/quasilinear-absorption problem using gyrokinetics. Questions of when and under what conditions local energy should be of definite sign are best answered using the action-angle formalism. An important result is that the ''dielectric operators'' of the linearized wave equation and of the local energy are not the same, a fact which is obscured when the eikonal or WKB assumption is invoked. Even though the two dielectrics are very different in character (one operates linearly on electric field for the plasma current, the other operates quadratically for the energy), it is demonstrated that they are nevertheless related by a simple mathematical statement. This study was originally motivated by concern and lively discussion over the questions of local energy for rf-heating of plasmas, where in certain instances, full-wave effects such as refraction, strong absorption, and mode conversion are of primary importance. Fundamentally, the rf-absorption must equate with the energy moment of the quasilinear term to achieve a correct energy balance. This fact governs the derivation (as opposed to postulation) of the local absorption. The troublesome ''kinetic flux'' may then be chosen (it is not unique) to satisfy a wave-energy balance relation with the Poynting flux and local absorption. It is shown that at least one such choice reduces asymptotically to the Stix form away from nonuniformities, thereby demonstrating energy conservation to all orders in Larmor radius. 25 refs.

  18. Financing renewable energy for Village Power application

    SciTech Connect

    Santibanez-Yeneza, G.

    1997-12-01

    When one talks of rural development, no doubt, the issue of rural energy is not far behind. As a significant component of any development strategy, rural energy is seen as the engine for growth that can bring about economic upliftment in the countryside. Many approaches to rural energy development have been tried. These approaches differ from country to country. But regardless of structure and approach, the goal remain essentially the same: to provide rural communities access to reliable energy services at affordable prices. In recent years, as global concern for the environment has increased, many governments have turned to renewable energy as a more environment friendly alternative to rural electrification. Technological advances in renewable energy application has helped to encourage this use. System reliability has improved, development costs have, to some extent been brought down and varied application approaches have been tried and tested in many areas. Indeed, there is huge potential for the development of renewable energy in the rural areas of most developing countries. At the rural level, renewable energy resources are almost always abundantly available: woodwaste, agricultural residues, animal waste, small-scale hydro, wind, solar and even sometimes geothermal resources. Since smaller scale systems are usually expected in these areas, renewable energy technologies can very well serve as decentralized energy systems for rural application. And not only for rural applications, new expansion planning paradigms have likewise led to the emergence of decentralized energy systems not only as supply options but also as corrective measures for maintaining end of line voltage levels. On the other hand, where renewable energy resource can provide significant blocks of power, they can be relied upon to provide indigenous power to the grids.

  19. Modeling radiation belt radial diffusion in ULF wave fields: 1. Quantifying ULF wave power at geosynchronous orbit in observations and in global MHD model

    Microsoft Academic Search

    Chia-Lin Huang; Harlan E. Spence; Howard J. Singer; W. Jeffrey Hughes

    2010-01-01

    To provide critical ULF wave field information for radial diffusion studies in the radiation belts, we quantify ULF wave power (f = 0.5–8.3 mHz) in GOES observations and magnetic field predictions from a global magnetospheric model. A statistical study of 9 years of GOES data reveals the wave local time distribution and power at geosynchronous orbit in field-aligned coordinates as

  20. Phase-locking and coherent power combining of broadband linearly chirped optical waves.

    PubMed

    Satyan, Naresh; Vasilyev, Arseny; Rakuljic, George; White, Jeffrey O; Yariv, Amnon

    2012-11-01

    We propose, analyze and demonstrate the optoelectronic phase-locking of optical waves whose frequencies are chirped continuously and rapidly with time. The optical waves are derived from a common optoelectronic swept-frequency laser based on a semiconductor laser in a negative feedback loop, with a precisely linear frequency chirp of 400 GHz in 2 ms. In contrast to monochromatic waves, a differential delay between two linearly chirped optical waves results in a mutual frequency difference, and an acoustooptic frequency shifter is therefore used to phase-lock the two waves. We demonstrate and characterize homodyne and heterodyne optical phase-locked loops with rapidly chirped waves, and show the ability to precisely control the phase of the chirped optical waveform using a digital electronic oscillator. A loop bandwidth of ~ 60 kHz, and a residual phase error variance of < 0.01 rad(2) between the chirped waves is obtained. Further, we demonstrate the simultaneous phase-locking of two optical paths to a common master waveform, and the ability to electronically control the resultant two-element optical phased array. The results of this work enable coherent power combining of high-power fiber amplifiers-where a rapidly chirping seed laser reduces stimulated Brillouin scattering-and electronic beam steering of chirped optical waves. PMID:23187338

  1. Measurements of radiated elastic wave energy from dynamic tensile cracks

    NASA Technical Reports Server (NTRS)

    Boler, Frances M.

    1990-01-01

    The role of fracture-velocity, microstructure, and fracture-energy barriers in elastic wave radiation during a dynamic fracture was investigated in experiments in which dynamic tensile cracks of two fracture cofigurations of double cantilever beam geometry were propagating in glass samples. The first, referred to as primary fracture, consisted of fractures of intact glass specimens; the second configuration, referred to as secondary fracture, consisted of a refracture of primary fracture specimens which were rebonded with an intermittent pattern of adhesive to produce variations in fracture surface energy along the crack path. For primary fracture cases, measurable elastic waves were generated in 31 percent of the 16 fracture events observed; the condition for radiation of measurable waves appears to be a local abrupt change in the fracture path direction, such as occurs when the fracture intersects a surface flaw. For secondary fractures, 100 percent of events showed measurable elastic waves; in these fractures, the ratio of radiated elastic wave energy in the measured component to fracture surface energy was 10 times greater than for primary fracture.

  2. Electrojet-independent ionospheric extremely low frequency/very low frequency wave generation by powerful high frequency waves

    SciTech Connect

    Kuo, Spencer [Polytechnic Institute of New York University, 6 MetroTech Center, Brooklyn, New York 11201 (United States); Snyder, Arnold [NorthWest Research Associates, P.O. Box 530, Stockton Springs, Maine 04981 (United States); Chang, Chia-Lie [BAE Systems-Technology Solutions, 2000 North 15th Street, Suite 1100, Arlington, Virginia 22201-2627 (United States)

    2010-08-15

    Results of extremely low frequency/very low frequency (ELF/VLF) wave generation by intensity-modulated high frequency (HF) heaters of 3.2 MHz in Gakona, Alaska, near local solar noon during a geomagnetic quiet time, are presented to support an electrojet-independent ELF/VLF wave generation mechanism. The modulation was set by splitting the HF transmitter array into two subarrays; one was run at cw full power and the other run alternatively at 50% and 100% power modulation by rectangular waves of 2.02, 5, 8, and 13 kHz. The most effective generation was from the X-mode heater with 100% modulation. While the 8 kHz radiation has the largest wave amplitude, the spectral intensity of the radiation increases with the modulation frequency, i.e., 13 kHz line is the strongest. Ionograms recorded significant virtual height spread of the O-mode sounding echoes. The patterns of the spreads and the changes of the second and third hop virtual height traces caused by the O/X-mode heaters are distinctively different, evidencing that it is due to differently polarized density irregularities generated by the filamentation instability of the O/X-mode HF heaters.

  3. Nuclear Power and the World's Energy Requirements

    E-print Network

    V. Castellano; R. F. Evans; J. Dunning-Davies

    2004-06-10

    The global requirements for energy are increasing rapidly as the global population increases and the under-developed nations become more advanced. The traditional fuels used in their traditional ways will become increasingly unable to meet the demand. The need for a review of the energy sources available is paramount, although the subsequent need to develop a realistic strategy to deal with all local and global energy requirements is almost as important. Here attention will be restricted to examining some of the claims and problems of using nuclear power to attempt to solve this major question.

  4. Spectral estimates of gravity wave energy and momentum fluxes. Part I: Energy dissipation, acceleration, and constraints

    Microsoft Academic Search

    David C. Fritts; Thomas E. Vanzandt

    1993-01-01

    The spectral characteristics of atmospheric gravity wave motions are remarkably uniform in frequency and wavenumber despite widely despite sources, filtering environments, and altitudes of observation. This permits a convenient and useful means of describing mean spectral parameters, including energy density, anisotropy, energy and momentum fluxes, and wave influences on their environment. The purpose here is to provide a general formulation

  5. 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.

  6. Integrating thermal energy storage in power plants

    SciTech Connect

    Somasundaram, S.; Drost, M.K.; Brown, D.R.; Antoniak, Z.I. (Pacific Northwest Lab., Richland, WA (United States))

    1993-09-01

    This article describes a system that stores thermal energy in a natural gas-fired cogeneration facility uses a gas turbine, a heat recovery salt heater, and salt-heated steam generator. The National Energy Strategy forecast estimates that 200,000 megawatts-electric (MWe) of new electric-generating capacity will need to be added to the US nationally by the year 2010. Approximately 40 percent of this new generating capacity will be for peak or intermediate loads, with the rest providing continuous baseload power generation. Natural gas-fired combustion turbine technologies, including cogeneration, combined-cycle, and integrated gasification combined-cycle power plants, are becoming the generating options of choice because of their flexibility, relatively low capital cost, reduced environmental impact, and increasing thermal efficiency. Thermal energy storage (TES) for utility applications includes a range of technologies that can further improve the efficiency, flexibility, and economics of gas turbine options.

  7. Wave energy estimation by using a statistical analysis and wave buoy data near the southern Caspian Sea

    NASA Astrophysics Data System (ADS)

    Zamani, A. R.; Badri, M. A.

    2015-04-01

    Statistical analysis was done on simultaneous wave and wind using data recorded by discus-shape wave buoy. The area is located in the southern Caspian Sea near the Anzali Port. Recorded wave data were obtained through directional spectrum wave analysis. Recorded wind direction and wind speed were obtained through the related time series as well. For 12-month measurements (May 25 2007-2008), statistical calculations were done to specify the value of nonlinear auto-correlation of wave and wind using the probability distribution function of wave characteristics and statistical analysis in various time periods. The paper also presents and analyzes the amount of wave energy for the area mentioned on the basis of available database. Analyses showed a suitable comparison between the amounts of wave energy in different seasons. As a result, the best period for the largest amount of wave energy was known. Results showed that in the research period, the mean wave and wind auto correlation were about three hours. Among the probability distribution functions, i.e Weibull, Normal, Lognormal and Rayleigh, "Weibull" had the best consistency with experimental distribution function shown in different diagrams for each season. Results also showed that the mean wave energy in the research period was about 49.88 kW/m and the maximum density of wave energy was found in February and March, 2010.

  8. Alaskan wave and river hydrokinetic energy resource assessment, river energy converter testing and surface debris mitigation performance

    NASA Astrophysics Data System (ADS)

    Johnson, J.; Kasper, J.; Schmid, J.; Duvoy, P.; Ravens, T. M.; Hansen, N.; Montlaur, A.

    2014-12-01

    The Alaska Hydrokinetic Energy Research Center (AHERC) is conducting a wave energy assessment study at Yakutat, Alaska, and conducting ongoing river technology studies at the Tanana River Tests Site (TRTS) at Nenana, Alaska. In Aug. 2013 an acoustic Doppler current profiler (ADCP) was deployed in 40 m of water off Cannon Beach in Yakutat, AK as part of the Yakutat area wave energy resource assessment. Over the course of the 1.5 year deployment, the ADCP will record area wave and current data in order to verify the area wave energy resource. Preliminary data analysis shows a vigorous wave field with maximum wave heights up to 16 m in Nov. 2013. In addition to the in-situ directional wave data recorded by the ADCP, a SWAN wave climatology spanning the past 20 years is being developed along with a simulation of the wave field for the near shore (5 mwave statistics provided by the ADCP. Technology studies at the TRTS include performance tests of a research debris diversion platform (RDDP) at protecting a 5 kW New Energy hydrokinetic turbine from river debris flows and to determine the effect of RDDP generated river current turbulence on turbine efficiency. Previous tests have shown that the RDDP effectively sheds debris, however, large debris objects can cause RDDP rotation about its mooring point requiring that a stable attachment between the RDDP and protected floating structure be in place to ensure that debris is diverted away from the protected structure. Performance tests of an Oceana hydrokinetic power turbine will be conducted in late August or early September, 2014 at the TRTS in realistic Alaskan river conditions of current turbulence, high sediment flow and debris. Measurements of river sediment concentration, current velocity and river stage will be made, and current turbulence will be derived. CFD simulations of the RDDP interaction with the river flow will be completed to compare current velocity and turbulence results, depending on the opening angle of the device. Study activities and results will be presented.

  9. Decay estimates for the one-dimensional wave equation with an inverse power potential

    E-print Network

    Roland Donninger; Wilhelm Schlag

    2010-03-10

    We study the wave equation on the real line with a potential that falls off like $|x|^{-\\alpha}$ for $|x| \\to \\infty$ where $2 energy and no bound states. As an application we consider the $\\ell=0$ Price Law for Schwarzschild black holes. This paper is part of our investigations into decay of linear waves on a Schwarzschild background.

  10. Wave Power for U.S. Coast Guard First District Lighthouses

    SciTech Connect

    Walker, A.; Kandt, A.; Heimiller, D.

    2006-01-01

    Lighthouses and other navigational aids are situated near tumultuous seas and thus may be good candidates for early applications of wave energy conversion technologies. This paper describes gravity wave physics and the characteristics of mechanical radiation (growth, propagation, diffraction, and shoaling).

  11. Method and apparatus for generating electric power by waves

    SciTech Connect

    Watabe, T.; Dote, Y.; Kondo, H.; Matsuda, T.; Takagi, M.; Yano, K.

    1984-12-25

    At least one caisson which is part or all of a breakwater forms a water chamber therein whose closure is a pendulum having a natural period in rocking or oscillating the same as a period of stationary wave surges caused in the water chamber by rocking movement of the pendulum owing to wave force impinging against the pendulum. At least one double-acting piston and cylinder assembly is connected to the pendulum, so that when a piston of the assembly is reciprocatively moved by the pendulum, pressure difference between cylinder chambers on both sides of the piston of the assembly controls a change-over valve which in turn controls hydraulic pressure discharged from the cylinder chambers to be supplied to a plurality of hydraulic motors respectively having accumulators of a type wherein accumulated pressure and volume of the hydraulic liquid are proportional to each other, whereby driving a common generator alternately by the hydraulic motors.

  12. Sleep Control for Base Stations Powered by Heterogeneous Energy Sources

    E-print Network

    to the power grid, some BSs are purely powered by the renewable energy. BS sleep is introduced not only to save grid power, but also to store renewable energy for future use when the temporal traffic variation does of those BS powered by the renewable energy, and this will lead to network coverage hole and thus severely

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

    E-print Network

    Victoria, University of

    and resulting device scaling. The results of the wave energy conversion with and without storage, as well ...................................................................................................... 9 2.3.5 Compressed air Wild Abstract Technologies exist that can capture and convert wave energy but there are few studies

  14. Optimal heave motion of some axisymmetric wave energy devices in sinusoidal waves

    Microsoft Academic Search

    M. Greenhow; S. P. White

    1997-01-01

    We present a mathematical model of the transient motion of a floating body wave energy device, including memory and an impulsive term. The memory is calculated from the damping coefficients in the frequency domain, and forms the kernel of an integral which is a component of the equation of motion to be solved numerically. The impulsive term is calculated from

  15. Fractal ladder models and power law wave equations

    PubMed Central

    Kelly, James F.; McGough, Robert J.

    2009-01-01

    The ultrasonic attenuation coefficient in mammalian tissue is approximated by a frequency-dependent power law for frequencies less than 100 MHz. To describe this power law behavior in soft tissue, a hierarchical fractal network model is proposed. The viscoelastic and self-similar properties of tissue are captured by a constitutive equation based on a lumped parameter infinite-ladder topology involving alternating springs and dashpots. In the low-frequency limit, this ladder network yields a stress-strain constitutive equation with a time-fractional derivative. By combining this constitutive equation with linearized conservation principles and an adiabatic equation of state, a fractional partial differential equation that describes power law attenuation is derived. The resulting attenuation coefficient is a power law with exponent ranging between 1 and 2, while the phase velocity is in agreement with the Kramers–Kronig relations. The fractal ladder model is compared to published attenuation coefficient data, thus providing equivalent lumped parameters. PMID:19813816

  16. Potential of Development and Application of Wave Energy Conversion Technology in the Gulf of Mexico

    E-print Network

    Guiberteau, K. L.; Liu, Y.; Lee, J.; Kozman, T.

    2014-01-01

    This paper focuses on the potential and application of developing wave energy technology in the Gulf of Mexico (GOM). The conditions (weather, wave climate, activity of the oil industry, etc.) in the GOM are assessed and the attributes of wave...

  17. Potential of Development and Application of Wave Energy Conversion Technology in the Gulf of Mexico 

    E-print Network

    Guiberteau, K. L.; Liu, Y.; Lee, J.; Kozman, T.

    2014-01-01

    This paper focuses on the potential and application of developing wave energy technology in the Gulf of Mexico (GOM). The conditions (weather, wave climate, activity of the oil industry, etc.) in the GOM are assessed and the attributes of wave...

  18. Computational simulation of the interactions between water waves and two-dimensional wave energy converters

    NASA Astrophysics Data System (ADS)

    Ghasemi, Amirmahdi; Pathak, Ashish; Chiodi, Robert; Raessi, Mehdi

    2013-11-01

    Ocean waves represent a vast renewable energy resource, which is mostly untapped. We present a computational tool for simulation of the interactions between waves and two-dimensional oscillating solid bodies representing simple wave energy converters (WECs). The computational tool includes a multiphase flow solver, in which the two-step projection method with GPU acceleration is used to solve the Navier-Stokes equations. The fictitious domain method is used to capture the interactions of a moving rigid solid body with the two-fluid flow. The solid and liquid volumes are tracked using the volume-of-fluid (VOF) method, while the triple points and phase interfaces in three-phase cells are resolved. A consistent mass and momentum transport scheme is used to handle the large density ratio. We present results of two wave generation mechanisms with a piston or flap wave maker, where the theoretical and experimental results were used for validation. Then, simulation results of several simple devices representative of distinct WECs, including a bottom-hinged flap device as well as cylindrical or rectangular terminators are presented. The results are in good agreement with the available experimental data.

  19. Sound power spectrum and wave drag of a propeller in flight

    NASA Technical Reports Server (NTRS)

    Hanson, D. B.

    1989-01-01

    Theory is presented for the sound power and sound power spectrum of a single rotation propeller in forward flight. Calculations are based on the linear wave equation with sources distributed over helicoidal surfaces to represent effects of blade thickness and steady loading. Sound power is distributed continuously over frequecy, as would be expected from Doppler effects, rather than in discrete harmonics. The theory is applied to study effects of sweep and Mach number in propfans. An acoustic efficiency is defined as the ratio of radiated sound power to shaft input power. This value is the linear estimate of the effect of wave drag due to the supersonic blade section speeds. It is shown that the acoustic efficiency is somewhat less than 1 percent for a well designed propfan.

  20. Ultra-power shock wave driven by a laser-accelerated electron beam

    NASA Astrophysics Data System (ADS)

    Gus’kov, S. Yu

    2015-06-01

    This review is presented on modern research to achieve in a laboratory experiment the new level of shock-wave pressure of a few hundred or even thousands of Mbar when a substance is exposed to a stream of laser-accelerated fast electrons. The applications associated with the use of ultra-power shock waves as the ignition driver of inertial fusion targets as well as the tool in studying the equation of a state of a matter are discussed.

  1. Complex permittivity and permeability measurements of ferrimagnets at Millimeter waves with high power sources

    Microsoft Academic Search

    Mohammed N. Afsar; Konstantin A. Korolev; Lakshmi Subramanian; Igor I. Tkachov

    2005-01-01

    We present complex dielectric permittivity and magnetic permeability characteristics of strontium and nickel ferrite ceramics in Q-, V-, and W-band frequency range. The measurements have been done using broad-band quasi-optical millimeter wave spectrometer with backward-wave oscillator as a high power source of coherent radiation. Dielectric and magnetic parameters of the ferrite ceramic materials have been calculated by employing the best

  2. Full-Wave Analysis of Power Distribution Networks in Printed Circuit Boards

    NASA Astrophysics Data System (ADS)

    Maradei, Francescaromana; Caniggia, Spartaco; Inverardi, Nicola; Rotigni, Mario

    This paper provides an investigation of power distribution network (PDN) performance by a full-wave prediction tool and by experimental measurements. A set of six real boards characterized by increasing complexity is considered in order to establish a solid base for behaviour understanding of printed circuit boards. How the growing complexity impacts on the board performance is investigated by measurements and by simulations. Strengths and weakness of PDN modeling by the full-wave software tool Microwave Studio are highlighted and discussed.

  3. Comparison of heaving buoy and oscillating flap wave energy converters

    NASA Astrophysics Data System (ADS)

    Abu Bakar, Mohd Aftar; Green, David A.; Metcalfe, Andrew V.; Najafian, G.

    2013-04-01

    Waves offer an attractive source of renewable energy, with relatively low environmental impact, for communities reasonably close to the sea. Two types of simple wave energy converters (WEC), the heaving buoy WEC and the oscillating flap WEC, are studied. Both WECs are considered as simple energy converters because they can be modelled, to a first approximation, as single degree of freedom linear dynamic systems. In this study, we estimate the response of both WECs to typical wave inputs; wave height for the buoy and corresponding wave surge for the flap, using spectral methods. A nonlinear model of the oscillating flap WEC that includes the drag force, modelled by the Morison equation is also considered. The response to a surge input is estimated by discrete time simulation (DTS), using central difference approximations to derivatives. This is compared with the response of the linear model obtained by DTS and also validated using the spectral method. Bendat's nonlinear system identification (BNLSI) technique was used to analyze the nonlinear dynamic system since the spectral analysis was only suitable for linear dynamic system. The effects of including the nonlinear term are quantified.

  4. Experimental observations of the spatial structure of wave-like disturbances generated in midlatitude ionosphere by high power radio waves

    NASA Astrophysics Data System (ADS)

    Kunitsyn, V.; Andreeva, E.; Padokhin, A. M.; Nazarenko, M.; Frolov, V.; Komrakov, G.; Bolotin, I.

    2012-12-01

    We present the results of the experiments carried out in 2009-2012 on the Sura heating facility (Radio Physical Research Institute, N. Novgorod, Russia) on modification of the midlatitude ionosphere by powerful HF radiowaves. The experiments were conducted using O-mode radiowaves at frequencies lower than critical frequency of the ionospheric F2 layer both in daytime and nighttime ionosphere. Various schemes of the radiation of the heating wave were used including square wave modulation of the effective radiated power (ERP) at various frequencies and power stepping. Radio transmissions of the low- (Parus/Tsikada) and high-orbital (GPS/GLONASS) navigational satellites received at the mobile network of receiving sites were used for the remote sensing of the heated area of the ionosphere. The variations in the slant total electron content (TEC), which are proportional to the reduced phase of navigational signals, were studied for the satellite passes for which ionospheric penetration points crossed the disturbed area during HF heating. The variations in TEC caused by HF heating are identified in a number of examples. It is shown that the GNSS TEC spectra contain frequency components corresponding to the modulation periods of the ERP of the heating wave. The manifestations of the heating-induced variations in TEC are most prominent in the area of magnetic zenith of the pumping wave. Different behavior of TEC variations was observed during nighttime and daytime heating experiments. In daytime conditions the pump wave switched ON causes the increase of TEC while in the nighttime it causes a decrease in TEC. This can be explained by the different contribution of the processes responsible for the increase and decrease of TEC in daytime in nighttime conditions. In this work we also present the first time radiotomographic reconstructions of the spatial structure of the wave-like disturbances, generated in the ionosphere by high-power radio waves radiated by the Sura heater with a square wave modulation of the ERP at a frequency lower than or of the order of the Brunt-Vaisala frequency of the neutral atmosphere. The observed wavelike structures, which are possibly AGWs, diverge from the heated area of the ionosphere (observed like a narrow trough with dimensions corresponding to the diagram pattern of the Sura heater), the spatial period of these disturbances is 200-250 km and they are easily traced up to a distance of 700-800 km from the heated region. These observations are in good agreement with complimentary GPS/GLONASS data. We also present the examples of amplitude scintillations of the signals of low-orbital radio beacons corresponding to small-scale field-aligned irregularities in the heated area of ionosphere. The possibility of generation of electromagnetic waves by moving wave-like structures in ionosphere (like AGWs induced by HF-heating observed in our experiments) is also addressed in this work. The authors are grateful to the staff of the Sura facility for their help in conducting the experiments and acknowledge the support of the Russian Foundation for Basic Research (grants 10-05-01126, 11-02-00374, 11-05-01157, 12-02-31839, 12-05-33065, 12-05-10068), grant of the President of Russian Federation MK-2544.2012.5 and Lomonosov Moscow State University Program of Development.

  5. Spectral estimates of gravity wave energy and momentum fluxes. Part 2: Parameterization of wave forcing and variability

    Microsoft Academic Search

    David C. Fritts; Wentong Lu

    1993-01-01

    A scheme is suggested for the parameterization of gravity wave propagation and effects in the lower and middle atmosphere that is tied as closely as possible to the spectral character of the observed gravity wave field. This effort begins with spectral expressions for gravity wave energy and momentum fluxes and prescribes the manner in which such idealized spectra respond to

  6. Energy Storage Applications in Power Systems with Renewable Energy Generation

    NASA Astrophysics Data System (ADS)

    Ghofrani, Mahmoud

    In this dissertation, we propose new operational and planning methodologies for power systems with renewable energy sources. A probabilistic optimal power flow (POPF) is developed to model wind power variations and evaluate the power system operation with intermittent renewable energy generation. The methodology is used to calculate the operating and ramping reserves that are required to compensate for power system uncertainties. Distributed wind generation is introduced as an operational scheme to take advantage of the spatial diversity of renewable energy resources and reduce wind power fluctuations using low or uncorrelated wind farms. The POPF is demonstrated using the IEEE 24-bus system where the proposed operational scheme reduces the operating and ramping reserve requirements and operation and congestion cost of the system as compared to operational practices available in the literature. A stochastic operational-planning framework is also proposed to adequately size, optimally place and schedule storage units within power systems with high wind penetrations. The method is used for different applications of energy storage systems for renewable energy integration. These applications include market-based opportunities such as renewable energy time-shift, renewable capacity firming, and transmission and distribution upgrade deferral in the form of revenue or reduced cost and storage-related societal benefits such as integration of more renewables, reduced emissions and improved utilization of grid assets. A power-pool model which incorporates the one-sided auction market into POPF is developed. The model considers storage units as market participants submitting hourly price bids in the form of marginal costs. This provides an accurate market-clearing process as compared to the 'price-taker' analysis available in the literature where the effects of large-scale storage units on the market-clearing prices are neglected. Different case studies are provided to demonstrate our operational-planning framework and economic justification for different storage applications. A new reliability model is proposed for security and adequacy assessment of power networks containing renewable resources and energy storage systems. The proposed model is used in combination with the operational-planning framework to enhance the reliability and operability of wind integration. The proposed framework optimally utilizes the storage capacity for reliability applications of wind integration. This is essential for justification of storage deployment within regulated utilities where the absence of market opportunities limits the economic advantage of storage technologies over gas-fired generators. A control strategy is also proposed to achieve the maximum reliability using energy storage systems. A cost-benefit analysis compares storage technologies and conventional alternatives to reliably and efficiently integrate different wind penetrations and determines the most economical design. Our simulation results demonstrate the necessity of optimal storage placement for different wind applications. This dissertation also proposes a new stochastic framework to optimally charge and discharge electric vehicles (EVs) to mitigate the effects of wind power uncertainties. Vehicle-to-grid (V2G) service for hedging against wind power imbalances is introduced as a novel application for EVs. This application enhances the predictability of wind power and reduces the power imbalances between the scheduled output and actual power. An Auto Regressive Moving Average (ARMA) wind speed model is developed to forecast the wind power output. Driving patterns of EVs are stochastically modeled and the EVs are clustered in the fleets of similar daily driving patterns. Monte Carlo Simulation (MCS) simulates the system behavior by generating samples of system states using the wind ARMA model and EVs driving patterns. A Genetic Algorithm (GA) is used in combination with MCS to optimally coordinate the EV fleets for their V2G services and minimize the penalty cost associated wit

  7. Effect of energy deposited by cosmic-ray particles on interferometric gravitational wave detectors

    E-print Network

    Kazuhiro Yamamoto; Hideaki Hayakawa; Atsushi Okada; Takashi Uchiyama; Shinji Miyoki; Masatake Ohashi; Kazuaki Kuroda; Nobuyuki Kanda; Daisuke Tatsumi; Yoshiki Tsunesada

    2008-08-03

    We investigated the noise of interferometric gravitational wave detectors due to heat energy deposited by cosmic-ray particles. We derived a general formula that describes the response of a mirror against a cosmic-ray passage. We found that there are differences in the comic-ray responses (the dependence of temperature and cosmic-ray track position) in cases of interferometric and resonant gravitational wave detectors. The power spectral density of vibrations caused by low-energy secondary muons is 100-times smaller than the goal sensitivity of future second-generation interferometer projects, such as LCGT and Advanced LIGO. The arrival frequency of high-energy cosmic-ray muons that generate enough large showers inside mirrors of LCGT and Advanced LIGO is one per a millennium. We also discuss the probability of exotic-particle detection with interferometers.

  8. Calculations of the heights, periods, profile parameters, and energy spectra of wind waves

    NASA Technical Reports Server (NTRS)

    Korneva, L. A.

    1975-01-01

    Sea wave behavior calculations require the precalculation of wave elements as well as consideration of the spectral functions of ocean wave formation. The spectrum of the random wave process is largely determined by the distribution of energy in the actual wind waves observed on the surface of the sea as expressed in statistical and spectral characteristics of the sea swell.

  9. The influence of solar wind variability on magnetospheric ULF wave power

    NASA Astrophysics Data System (ADS)

    Pokhotelov, D.; Rae, I. J.; Murphy, K. R.; Mann, I. R.

    2015-06-01

    Magnetospheric ultra-low frequency (ULF) oscillations in the Pc 4-5 frequency range play an important role in the dynamics of Earth's radiation belts, both by enhancing the radial diffusion through incoherent interactions and through the coherent drift-resonant interactions with trapped radiation belt electrons. The statistical distributions of magnetospheric ULF wave power are known to be strongly dependent on solar wind parameters such as solar wind speed and interplanetary magnetic field (IMF) orientation. Statistical characterisation of ULF wave power in the magnetosphere traditionally relies on average solar wind-IMF conditions over a specific time period. In this brief report, we perform an alternative characterisation of the solar wind influence on magnetospheric ULF wave activity through the characterisation of the solar wind driver by its variability using the standard deviation of solar wind parameters rather than a simple time average. We present a statistical study of nearly one solar cycle (1996-2004) of geosynchronous observations of magnetic ULF wave power and find that there is significant variation in ULF wave powers as a function of the dynamic properties of the solar wind. In particular, we find that the variability in IMF vector, rather than variabilities in other parameters (solar wind density, bulk velocity and ion temperature), plays the strongest role in controlling geosynchronous ULF power. We conclude that, although time-averaged bulk properties of the solar wind are a key factor in driving ULF powers in the magnetosphere, the solar wind variability can be an important contributor as well. This highlights the potential importance of including solar wind variability especially in studies of ULF wave dynamics in order to assess the efficiency of solar wind-magnetosphere coupling.

  10. Investigation of Wave Energy Converter Effects on Near-shore Wave Fields: Model Generation Validation and Evaluation - Kaneohe Bay HI.

    SciTech Connect

    Roberts, Jesse D.; Chang, Grace; Jones, Craig

    2014-09-01

    The numerical model, SWAN (Simulating WAves Nearshore) , was used to simulate wave conditions in Kaneohe Bay, HI in order to determine the effects of wave energy converter ( WEC ) devices on the propagation of waves into shore. A nested SWAN model was validated then used to evaluate a range of initial wave conditions: significant wave heights (H s ) , peak periods (T p ) , and mean wave directions ( MWD) . Differences between wave height s in the presence and absence of WEC device s were assessed at locations in shore of the WEC array. The maximum decrease in wave height due to the WEC s was predicted to be approximately 6% at 5 m and 10 m water depths. Th is occurred for model initiation parameters of H s = 3 m (for 5 m water depth) or 4 m (10 m water depth) , T p = 10 s, and MWD = 330deg . Subsequently, bottom orbital velocities were found to decrease by about 6%.

  11. Power Supplies for High Energy Particle Accelerators

    NASA Astrophysics Data System (ADS)

    Dey, Pranab Kumar

    2015-05-01

    The on-going research and the development projects with Large Hadron Collider at CERN, Geneva, Switzerland has generated enormous enthusiasm and interest amongst all to know about the ultimate findings on `God's Particle'. This paper has made an attempt to unfold the power supply requirements and the methodology adopted to provide the stringent demand of such high energy particle accelerators during the initial stages of the search for the ultimate particles. An attempt has also been made to highlight the present status on the requirement of power supplies in some high energy accelerators with a view that, precautionary measures can be drawn during design and development from earlier experience which will be of help for the proposed third generation synchrotron to be installed in India at a huge cost.

  12. Performance Prediction of OWC Type Small Size Wave Power Device with Impulse Turbine

    NASA Astrophysics Data System (ADS)

    Suzuki, Masami; Takao, Manabu; Satoh, Eiji; Nagata, Shuichi; Toyota, Kazutaka; Setoguchi, Toshiaki

    This paper investigates a small size wave power device with an impulse turbine installed in the breakwater near Niigata Port, Japan. The device consists of an air chamber, a turbine, a generator and pressure-relief valves. This study reveals the characteristics of each component in this system with impulse turbine and a direct current dynamo the power of which is consumed by a constant resistor. In this paper special features of the impulse turbine are found, and the system characteristics are briefly represented. The overall plant performance was analyzed using mathematical model of an oscillating water column (OWC) based on linear water wave theory and the special features of the impulse turbine.

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

    E-print Network

    Peng, En Titus

    1991-01-01

    HIGH-POWER AND WAVELENGTH-TUNABLE TRAVELING-WAVE SEMICONDUCTOR RING LASER A Thesis EN TITUS PENG Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE... May 1991 Major Subject: Electrical Engineering HIGH-POWER AND WAVELENGTH-TUNABLE TRAVELING-WAVE SEMICONDUCTOR RING LASER A Thesis by EN TITUS PENG Approved as to style and content by: Ch' B. Su (Chair of Committee) 0, 4 Ohannes E n yan...

  14. Power Management for Energy Harvesting Wireless Sensors

    Microsoft Academic Search

    S. W. Arms; C. P. Townsend; D. L. Churchill; J. H. Galbreath; S. W. Mundell

    2005-01-01

    The objective of this work was to demonstrate smart wireless sensing nodes capable of operation at extremely low power levels. These systems were designed to be compatible with energy harvesting systems using piezoelectric materials and\\/or solar cells. The wireless sensing nodes included a microprocessor, on-board memory, sensing means (1000 ohm foil strain gauge), sensor signal conditioning, 2.4 GHz IEEE 802.15.4

  15. Electric Power From Ambient Energy Sources

    SciTech Connect

    DeSteese, John G.; Hammerstrom, Donald J.; Schienbein, Lawrence A.

    2000-10-03

    This report summarizes research on opportunities to produce electric power from ambient sources as an alternative to using portable battery packs or hydrocarbon-fueled systems in remote areas. The work was an activity in the Advanced Concepts Project conducted by Pacific Northwest National Laboratory (PNNL) for the Office of Research and Development in the U.S. Department of Energy Office of Nonproliferation and National Security.

  16. Energy flux measurement from the dissipated energy in capillary wave turbulence Luc Deike, Michael Berhanu, and Eric Falcon

    E-print Network

    Paris-Sud XI, Université de

    Energy flux measurement from the dissipated energy in capillary wave turbulence Luc Deike, Michael the dissipation is increased. The energy dissipated by capillary waves is also measured and found to increase with the frequency and the newly defined mean energy flux are in good agreement with wave turbulence theory

  17. Power Electronics and Motor Drives Laboratory Integrating Energy Storage withIntegrating Energy Storage with

    E-print Network

    Saldin, Dilano

    Energy Storage Integrated with Renewable Energy Energy Storage Analysis for Wind and Solar #12;Power;Power Electronics and Motor Drives Laboratory Wind and Solar Energy Outlook The U.S. wind power industry HG VH PO LO MD HG HG VH #12;Power Electronics and Motor Drives Laboratory Wind Power Generation vs

  18. High power, high efficiency 32 GHz space traveling wave tube

    Microsoft Academic Search

    N. R. Robbins; H. C. Limburg; D. R. Dibb; R. T. Benton; J. T. Burdette; W. L. Menninger; X. Zhai

    2004-01-01

    Boeing Electron Dynamic Devices, Inc. in collaboration with NASA Glenn Research Center, has demonstrated 100 W CW and 60% overall efficiency at 32 GHz in a TWT designed for deep space communications applications. Additionally, the TWT is designed to allow for variable output power levels, from 50 to 150 W, depending on mission requirements. The Boeing 999H is a helix

  19. Wave forces on an array of oscillating water column type free standing wave energy caissons

    SciTech Connect

    Neelamani, S.; Thiruvenkatasamy, K. [Indian Inst. of Technology, Madras (India). Ocean Engineering Centre

    1995-12-31

    The wave induced in-line forces on a 1:50 scale model of an array of Multi resonant Oscillating Water Column (MOWC) type free standing wave energy caisson were experimentally investigated. A range of hydrodynamic parameters with different damping of oscillating water column (OWC) chamber and various center to center spacings between the caissons were used. In general, the force on the MOWC caisson array is two times that of a vertical wall, for maximum damping of OWC chamber. Reduction of damping of the OWC air chamber reduces the force on the array of caissons. With reduced damping, forces on OWC array can even be smaller than that the ones on a vertical wall. For smaller center to center (C/C) spacing between the caissons with respect to its harbor width, OWC array acts like a perforated breakwater, attracting smaller wave forces and for higher C/C spacing, it behaves like a vertical wall.

  20. MAGNETOACOUSTIC WAVE ENERGY FROM NUMERICAL SIMULATIONS OF AN OBSERVED SUNSPOT UMBRA

    SciTech Connect

    Felipe, T.; Khomenko, E.; Collados, M., E-mail: tobias@iac.es [Instituto de Astrofisica de Canarias, 38205, C/Via Lactea, s/n, La Laguna, Tenerife (Spain)

    2011-07-01

    We aim at reproducing the height dependence of sunspot wave signatures obtained from spectropolarimetric observations through three-dimensional MHD numerical simulations. A magnetostatic sunspot model based on the properties of the observed sunspot is constructed and perturbed at the photosphere, introducing the fluctuations measured with the Si I {lambda}10827 line. The results of the simulations are compared with the oscillations observed simultaneously at different heights from the He I {lambda}10830 line, the Ca II H core, and the Fe I blends in the wings of the Ca II H line. The simulations show a remarkable agreement with the observations. They reproduce the velocity maps and power spectra at the formation heights of the observed lines, as well as the phase and amplification spectra between several pairs of lines. We find that the stronger shocks at the chromosphere are accompanied with a delay between the observed signal and the simulated one at the corresponding height, indicating that shocks shift the formation height of the chromospheric lines to higher layers. Since the simulated wave propagation matches very well the properties of the observed one, we are able to use the numerical calculations to quantify the energy contribution of the magnetoacoustic waves to the chromospheric heating in sunspots. Our findings indicate that the energy supplied by these waves is too low to balance the chromospheric radiative losses. The energy contained at the formation height of the lowermost Si I {lambda}10827 line in the form of slow magnetoacoustic waves is already insufficient to heat the higher layers, and the acoustic energy which reaches the chromosphere is around 3-9 times lower than the required amount of energy. The contribution of the magnetic energy is even lower.

  1. Magnetoacoustic Wave Energy from Numerical Simulations of an Observed Sunspot Umbra

    NASA Astrophysics Data System (ADS)

    Felipe, T.; Khomenko, E.; Collados, M.

    2011-07-01

    We aim at reproducing the height dependence of sunspot wave signatures obtained from spectropolarimetric observations through three-dimensional MHD numerical simulations. A magnetostatic sunspot model based on the properties of the observed sunspot is constructed and perturbed at the photosphere, introducing the fluctuations measured with the Si I ?10827 line. The results of the simulations are compared with the oscillations observed simultaneously at different heights from the He I ?10830 line, the Ca II H core, and the Fe I blends in the wings of the Ca II H line. The simulations show a remarkable agreement with the observations. They reproduce the velocity maps and power spectra at the formation heights of the observed lines, as well as the phase and amplification spectra between several pairs of lines. We find that the stronger shocks at the chromosphere are accompanied with a delay between the observed signal and the simulated one at the corresponding height, indicating that shocks shift the formation height of the chromospheric lines to higher layers. Since the simulated wave propagation matches very well the properties of the observed one, we are able to use the numerical calculations to quantify the energy contribution of the magnetoacoustic waves to the chromospheric heating in sunspots. Our findings indicate that the energy supplied by these waves is too low to balance the chromospheric radiative losses. The energy contained at the formation height of the lowermost Si I ?10827 line in the form of slow magnetoacoustic waves is already insufficient to heat the higher layers, and the acoustic energy which reaches the chromosphere is around 3-9 times lower than the required amount of energy. The contribution of the magnetic energy is even lower.

  2. Liu UCD Phy9B 07 22 15-5. Energy in Wave Motion

    E-print Network

    Yoo, S. J. Ben

    Liu UCD Phy9B 07 22 15-5. Energy in Wave Motion x txy FtxFy -= ),( ),( t txy x txy FtxvtxFtxP yy -== ),(),( ),(),(),( For any wave on a string, instantaneous rate of energy transfer 1 dimensional: wave on a string #12;Liu UCD Phy9B 07 23 Energy Transferred by Sinusoidal Wave )cos(),( tkxAtxy -= For a sinusoidal wave )(sin

  3. An alternative method for calculating the energy of gravitational waves

    E-print Network

    Miroslav Sukenik; Jozef Sima

    1999-09-21

    In the expansive nondecelerative universe model, creation of matter occurs due to which the Vaidya metrics is applied. This fact allows for localizing gravitational energy and calculating the energy of gravitational waves using an approach alternative to the well established procedure based on quadrupole formula. Rationalization of the gradual increase in entropy of the Universe using relation describing the total curvature of space-time is given too.

  4. Wing Wave: Feasible, Alternative, Renewable, Electrical Energy Producing Ocean Floor System

    E-print Network

    Wood, Stephen L.

    Wing Wave: Feasible, Alternative, Renewable, Electrical Energy Producing Ocean Floor System Mark, alternative energy system to convert the circular motion of ocean waves as they propagate through the sea and feasible alternative, renewable, electrical energy producing subsea system. Index Terms--ocean energy, wave

  5. Power and energy [1999 technology analysis and forecast

    Microsoft Academic Search

    W. Sweet

    1999-01-01

    This article presents a power and energy technology analysis and forecast for 1999. The subjects covered include photovoltaics, PV power systems, solar arrays, nuclear power and free market spot electricity pricing

  6. ENERGY PAYBACK OPTIMIZATION OF THERMOELECTRIC POWER GENERATOR SYSTEMS

    E-print Network

    ENERGY PAYBACK OPTIMIZATION OF THERMOELECTRIC POWER GENERATOR SYSTEMS Kazuaki Yazawa Dept model for optimizing thermoelectric power generation system is developed and utilized for parametric a fractional area of ~1%. The role of the substrate heat spreading for thermoelectric power generation

  7. Optimization of Reaction Plates for Wave Energy Conversion

    NASA Astrophysics Data System (ADS)

    Brown, A. C.

    2014-12-01

    Reaction forces are generated as energy is extracted from the motion of ocean waves relative to a wave energy converter (WEC). The reaction forces effect the momentum of the WEC, and in most cases it is beneficial to transfer the loads to a relatively stationary external body. It has become common for WECs to include reaction plates that use hydrodynamic damping to transfer the loads developed during energy extraction to the relatively stationary water below the surface of the ocean. Reaction plates allow WECs to use compliant moorings, which reduce mooring loads and are more easily deployed than taut moorings. Heave plates are commonly used on offshore platforms, but the design of reaction plates for wave energy converters has received little attention. This work presents an initial optimization of reaction plate form to improve the heave and surge performance of the WEC reference models developed for the US Department of Energy. The benefits and drawbacks of various reaction plate geometries are compared, and the impacts on WEC stability, peak loading, and energy production are considered.

  8. 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.

  9. Development of a high power 12GHz PPM focused traveling wave tube

    NASA Technical Reports Server (NTRS)

    Lewis, R.

    1975-01-01

    An analytical and experimental program to demonstrate the technical feasibility of a high efficiency coupled cavity traveling wave tube with periodic permanent magnetic focusing operating at 12.06 GHz, with 1 to 2 kilowatts CW power is described. Such a tube would ultimately be used for broadcasting power transmission from a satellite. The electron gun was designed to be demountable with a replaceable cathode, and the tube to be operable in a bakeable vacuum chamber with its collector replaced by a collector. Therefore, the high efficiency design was concerned with the slow wave structure only, utilizing velocity resynchronization. A special adapter was designed which incorporated an electromagnet refocusing section and a collector baseplate to facilitate testing the collector. CW output power of 1000 watts yielding 21.5% electronic efficiency was demonstrated, with a minimum output power of 525 watts across the specified 160 MHz bandwidth.

  10. Effects of Wave Energy Converter (WEC) Arrays on Wave, Current, and Sediment Circulation

    NASA Astrophysics Data System (ADS)

    Ruehl, K.; Roberts, J. D.; Jones, C.; Magalen, J.; James, S. C.

    2012-12-01

    The characterization of the physical environment and commensurate alteration of that environment due to Wave Energy Conversion (WEC) devices, or arrays of devices, must be understood to make informed device-performance predictions, specifications of hydrodynamic loads, and environmental evaluations of eco-system responses (e.g., changes to circulation patterns, sediment dynamics, and water quality). Hydrodynamic and sediment issues associated with performance of wave-energy devices will primarily be nearshore where WEC infrastructure (e.g., anchors, piles) are exposed to large forces from the surface-wave action and currents. Wave-energy devices will be subject to additional corrosion, fouling, and wear of moving parts caused by suspended sediments in the water column. The alteration of the circulation and sediment transport patterns may also alter local ecosystems through changes in benthic habitat, circulation patterns, or other environmental parameters. Sandia National Laboratories is developing tools and performing studies to quantitatively characterize the environments where WEC devices may be installed and to assess potential affects to hydrodynamics and local sediment transport. The primary tools are wave, hydrodynamic, and sediment transport models. To ensure confidence in the resulting evaluation of system-wide effects, the models are appropriately constrained and validated with measured data where available. An extension of the US EPA's EFDC code, SNL-EFDC, provides a suitable platform for modeling the necessary hydrodynamics;it has been modified to directly incorporate output from a SWAN wave model of the region. Model development and results are presented. In this work, a model is exercised for Monterey Bay, near Santa Cruz where a WEC array could be deployed. Santa Cruz is located on the northern coast of Monterey Bay, in Central California, USA. This site was selected for preliminary research due to the readily available historical hydrodynamic data (currents and wave heights, periods, and directions), sediment characterization data, and near-shore bathymetric data. In addition, the region has been under evaluation for future ocean energy projects. The modeling framework of SWAN and SNL-EFDC combined with field validation datasets allows for a robust quantitative description of the nearshore environment within which the MHK devices will be evaluated. This quantitative description can be directly incorporated into environmental impact assessments to eliminate guesswork related to the effects of the presence of large-scale arrays. These results can be used to design more efficient arrays while minimizing impacts on the nearshore environments. Further investigations into fine-scale scour near the structures will help determine if these large-scale results show that, in fact, there is deposition adjacent to the arrays, which could have design implications on anchorage and cabling systems.

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

    SciTech Connect

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

    1994-12-31

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

  12. An integrated millimeter-wave power-combiner using three- dimensional tapered gratings

    Microsoft Academic Search

    Carlos Enrique Saavedra-Munoz

    1998-01-01

    H scIGH-P scOWER amplification of millimeter-wave signals above several Watts is still the domain of electron tubes developed in the 1940's because current solid-state devices cannot deliver large amounts of power. Due to the advantages in cost, reliability, and physical size of solid-state devices over electron tubes, there has been a considerable amount of activity over the years to power-

  13. The RF-powered surface wave sensor oscillator - a successful alternative to passive wireless sensing

    Microsoft Academic Search

    Ivan D. Avramov

    2004-01-01

    A novel, passive wireless surface acoustic wave (SAW) sensor providing a highly coherent measurand proportional frequency, frequency modulated (FM) with identification (ID) data and immune to interference with multiple-path signals is described. The sensor is appropriate for bandwidth-limited applications requiring high-frequency accuracy. It comprises a low-power oscillator, stabilized with the sensing SAW resonator and powered by the rectified radio frequency

  14. High-power continuous-wave operation of quantum-cascade lasers up to 60°C

    Microsoft Academic Search

    J. S. Yu; A. Evans; J. David; L. Doris; S. Slivken; M. Razeghi

    2004-01-01

    High-temperature high-power continuous-wave (CW) operation of high-reflectivity-coated 12-?m-wide quantum-cascade lasers emitting at ? = 6 ?m with a thick electroplated Au top contact layer is reported for different cavity lengths. For a 3-mm-long laser, the CW optical output powers of 381 mW at 293 K and 22 mW at maximum operating temperature of 333 K (60°C) are achieved with threshold

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

    E-print Network

    Quinn E. Minor; Manoj Kaplinghat

    2015-03-08

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

  16. Traveling-wave photodetectors for high-power, large-bandwidth applications

    Microsoft Academic Search

    Vincent M. Hietala; G. Allen Vawter; T. M. Brennan; B. E. Hammons

    1995-01-01

    The traveling-wave photodetectors (TWPD) discussed here offer theoretical quantum efficiencies approaching 100% while maintaining a very large electrical bandwidth. Additionally, they are capable of dissipating the high-power levels required for large dynamic range applications. In this paper, the power dissipation limit of the TWPD is explored. A small-signal steady-state model is developed that includes the effects of electrical propagation losses

  17. Static power conversion techniques for unique energy devices 

    E-print Network

    Welch, Richard Andrew

    1998-01-01

    Solar power, fuel cells, and supercapacitors are some hics. of the new energy devices that are being used today in various power applications. The first two of these devices are exciting alternative sources of clean energy. The third device...

  18. Power processing and active protection for photovoltaic energy extraction

    E-print Network

    Chan, Arthur Hsu Chen

    2015-01-01

    Solar photovoltaic power generation is a promising clean and renewable energy technology that can draw upon the planet's most abundant power source - the sun. However, relatively high levelized cost of energy (LCOE), the ...

  19. Interconnection of electrical energy storage systems for power quality improvement

    Microsoft Academic Search

    M. Brenna; G. C. Lazaroiu; R. Rotaru; E. Tironi

    2009-01-01

    Energy storage is playing an increasingly important role in the electrical power system thanks to the development and advance in various energy storage and power electronics technologies in recent years. The paper inquires into energy storage examining electrical energy storage devices, especially supercapacitors. Relative on these energy storage concerns, different dc\\/dc converters were analyzed using the EMTP\\/ATPDraw program to observe

  20. Energy-momentum relation for solitary waves of nonlinear Dirac equations

    E-print Network

    T. V. Dudnikova

    2014-04-28

    Solitary waves of nonlinear Dirac, Maxwell-Dirac and Klein-Gordon-Dirac equations are considered. We prove that the energy-momentum relation for solitary waves coincides with the Einstein energy-momentum relation for point particles.

  1. Design of Calculation Software for Wave Process of Power Transformer Winding

    Microsoft Academic Search

    Yan Li; Xiqiang Xu; Dongxue Li

    2011-01-01

    Power transformer main and longitudinal insulation strength directly affects the safe and stable operation of the transformer. Therefore the reliability of the insulation is always the key links in transformer design. Impact characteristics of transformer winding is different with the different forms of winding structure, impulse wave cause oscillation in the winding, so it will produce oscillatory potentials which is

  2. Thermal behaviour and reliability of solidly mounted Bulk Acoustic Wave Duplexers under high power RF loads

    Microsoft Academic Search

    P. J. van der Wel; O. Wunnicke; F. de Bruijn; R. C. Strijbos

    2009-01-01

    In this paper, the reliability requirements, thermal behaviour and failure mechanisms of solidly mounted Bulk Acoustic Wave (BAW) filters are studied. High power RF stress measurements are presented where the evolution of the surface damage of the BAW filters as a function of stress time is analysed by optical height profiling. Two different metal stacks were used. The main failure

  3. Acoustic power and heat fluxes in the thermoacoustic effect due to a travelling plane wave

    Microsoft Academic Search

    Arturo O. Santillán; Ricardo R. Boullosa

    1997-01-01

    The thermoacoustic effect in a single plate due to a travelling plane wave is analyzed with respect to the conditions for the refrigerator or prime mover cycle to occur. The relation between the conduction of heat along a normal to the plate and the absorbed or generated acoustic power is also shown.

  4. Gain and continuous-wave laser power enhancement with a secondary discharge to predissociate molecular iodine

    E-print Network

    Carroll, David L.

    molecular iodine in an electric oxygen-iodine laser G. F. Benavides,1 J. W. Zimmerman,2 B. S. Woodard,2 D. L and 38% enhancement in continuous-wave laser power on the 1315 nm transition of atomic iodine through the addition of a secondary discharge to predissociate the molecular iodine in an electric oxygen-iodine laser

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

    E-print Network

    Boyer, Edmond

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

  6. Challenges to machine windings used in electrical generators in wave and tidal power plants

    Microsoft Academic Search

    Thomas Judendorfer; John Fletcher; Nagm Hassanain; Markus Mueller; Michael Muhr

    2009-01-01

    The majority of electrical generators in wave and tidal power plants are face harsh environmental conditions. Particularly the seals between the moving shaft and the stationary generator as these are mechanically stressed under pressure of the sea water. Flooding the electrical generator and the air gap respectively is a possible solution that would overcome seal failure. With this proposal, the

  7. Electromagnetic Wave Power Observed Near the Moon during Terrestrial Bow Shock Crossings

    E-print Network

    Fillingim, Matthew

    ( ) Electromagnetic (EM) sounding is a group of geophysical methods used to characterize the interiors of planetaryElectromagnetic Wave Power Observed Near the Moon during Terrestrial Bow Shock Crossings and Its Importance for Subsurface Sounding P41C-1631 Plasma Interactions P41C-1631 Plasma Interactions Observations

  8. Space traveling wave tube amplifiers with on-orbit flexible saturated output power

    Microsoft Academic Search

    Thomas K. Phelps; John D. McDowell; William L. Menninger

    2008-01-01

    This paper describes several approaches to achieving adjustable power output from a traveling wave tube amplifier. It can be adjusted in flight for maximum flexibility in matching the amplifier capability to the applicationpsilas need. The efficiency can be maximized without changing the hardware.

  9. Low-frequency square-wave electronic ballast with resonant ignition using digital mode and power

    E-print Network

    Low-frequency square-wave electronic ballast with resonant ignition using digital mode and power both the functions of a resonant circuit for lamp ignition and a current controlled low frequency is controlled as a FB inverter at the resonant frequency of the LC filter. After ignition the converter operates

  10. Increasing hurricane wave power along the U.S. Atlantic and Gulf coasts

    E-print Network

    Kossin, James P.

    coastal erosion and significant economic impacts [Davis et al., 1993; Dolan et al., 1988; Mather et al erosion along the North Carolina coast [Dolan and Davis, 1992]. From a coastal management and planning Mode. The annual wave power at near-coastal locations is closely associated with open ocean WPI

  11. Future Energy Systems: Integrating Renewable Energy Sources into the Smart Power Grid Through Industrial Electronics

    Microsoft Academic Search

    Marco Liserre; Thilo Sauter; John Hung

    2010-01-01

    This paper discusses about integrating renewable energy sources into the smart power grid through industrial electronics. This paper discusses photovoltaic power, wind energy conversion, hybrid energy systems, and tidal energy conversion.

  12. A New Methodology for Frequency Domain Analysis of Wave Energy Converters with Periodically Varying Physical Parameters

    NASA Astrophysics Data System (ADS)

    Mosher, Mark

    Within a wave energy converter's operational bandwidth, device operation tends to be optimal in converting mechanical energy into a more useful form at an incident wave period that is proximal to that of a power-producing mode of motion. Point absorbers, a particular classification of wave energy converters, tend to have a relative narrow optimal bandwidth. When not operating within the narrow optimal bandwidth, a point absorber's response and efficiency is attenuated. Given the wide range of sea-states that can be expected during a point absorber's operational life, these devices require a means to adjust, or control, their natural response to maximize the amount of energy absorbed in the large population of non-optimal conditions. In the field of wave energy research, there is considerable interest in the use of non-linear control techniques to this end. Non-linear control techniques introduce time-varying and state dependent control parameters into the point absorber motion equations, which usually motivates a computationally expensive numerical integration to determine the response of the device - important metrics such as gross converted power and relative travels of the device's pieces are extracted through post processing of the time series data. As an alternative, the work presented in this thesis was based on a closed form perturbation based approach for analysis of the response of a device with periodically-varying control parameters, subject to regular wave forcing, in the frequency domain. The proposed perturbation based method provides significant savings in computational time and enables the device's response to be represented in a closed form manner with a relatively small number of solution components - each component is comprised of a complex amplitude and oscillation frequency. This representation of the solution was found to be very concise and descriptive, and to lend itself to the calculation of gross absorbed power and travel constraint violations, making it extremely useful in the automated design optimization process; the methodology allows large number of design iterations, including both physical design and control variables, to be evaluated and conclusively compared. In the development of the perturbation method, it was discovered that the device's motion response can be calculated from an infinite series of second order ordinary differential equations that can be truncated without destroying the solution accuracy. It was found that the response amplitude operator for the generic form of a solution component provides a means to gauge the device's response to a given wave input and control parameter variation, including a gauge of the solution process stability. It is unclear as of yet if this is physical, a result of the solution process, or both. However, for a given control parameter set resulting in an unstable solution, the instability was shown to be, at least in part, a result of the device's dynamics. If the stability concerns can be addressed through additional constraints and updates to the wave energy converter hydrodynamic parameters, the methodology will expand on the commonly accepted boundaries for wave energy converter frequency-domain analysis methods and be of much practical importance in the evaluation of control techniques in the field of wave energy converter technology.

  13. PulsedPower Transient Plasma: Energy, Engines, and

    E-print Network

    Levi, Anthony F. J.

    -32) #12;5Gundersen PulsedPower USC ONR 1990s Transient Plasma NO Removal Results Energy cost function of V1Gundersen PulsedPower USC Transient Plasma: Energy, Engines, and Aerospace Applications USC: Dan energy electrons in streamer head produce radicals, ions · Nsec pulsed power enables! Transient plasma

  14. Wind energy-hydrogen storage hybrid power generation

    Microsoft Academic Search

    Wen-Jei Yang; Orhan Aydin

    2001-01-01

    SUMMARY In this theoretical investigation, a hybrid power generation system utilizing wind energy and hydrogen storage is presented. Firstly, the available wind energy is determined, which is followed by evaluating the e$ciency of the wind energy conversion system. A revised model of windmill is proposed from which wind power density and electric power output are determined. When the load demand

  15. Optical design of zero-power Hubble Space Telescope wave-front correctors for null testing

    NASA Technical Reports Server (NTRS)

    Hannan, Paul G.; Davila, Pam; Wood, H. J.

    1993-01-01

    The optical design of the second-generation wide-field/planetary-camera instrument for the Hubble Space Telescope has been modified to compensate for the spherical aberration of the optical telescope assembly (OTA) by introduction of undercorrected spherical aberration into the wave front. This instrument can be tested in a simple manner to ensure that its aberration contribution has the proper sign and magnitude. We present designs for a near-zero power doublet lens that can be used to generate a spherically aberrated wave front that is similar to the OTA wave front. When this lens is used in combination with the instrument, a near-perfect or nulled wave front should be produced, resulting in a high-quality point image on axis. We also present lens designs for a similar test that can be performed on the OTA simulators now being built to verify the other second-generation instruments.

  16. UNCERTAINTY EVALUATION OF AVAILABLE ENERGY AND POWER

    SciTech Connect

    Jon P. Christophersen; John L. Morrison

    2006-05-01

    The Idaho National Laboratory does extensive testing and evaluation of advanced technology batteries and ultracapacitors for applications in electric and hybrid vehicles. The testing is essentially acquiring time records of voltage, current and temperature from a variety of charge and discharge time profiles. From these three basic measured parameters, a complex assortment of derived parameters (resistance, power, etc.) is computed. Derived parameters are in many cases functions of multiple layers of other derived parameters that eventually work back to the three basic measured parameters. The purpose of this paper is to document the methodology used for the uncertainty analysis of the most complicated derived parameters broadly grouped as available energy and available power. This work is an analytical derivation. Future work will report the implementation of algorithms based upon this effort.

  17. Blast Shock Wave Mitigation Using the Hydraulic Energy Redirection and Release Technology

    PubMed Central

    Chen, Yun; Huang, Wei; Constantini, Shlomi

    2012-01-01

    A hydraulic energy redirection and release technology has been developed for mitigating the effects of blast shock waves on protected objects. The technology employs a liquid-filled plastic tubing as a blast overpressure transformer to transfer kinetic energy of blast shock waves into hydraulic energy in the plastic tubings. The hydraulic energy is redirected through the plastic tubings to the openings at the lower ends, and then is quickly released with the liquid flowing out through the openings. The samples of the specifically designed body armor in which the liquid-filled plastic tubings were installed vertically as the outer layer of the body armor were tested. The blast test results demonstrated that blast overpressure behind the body armor samples was remarkably reduced by 97% in 0.2 msec after the liquid flowed out of its appropriate volume through the openings. The results also suggested that a volumetric liquid surge might be created when kinetic energy of blast shock wave was transferred into hydraulic energy to cause a rapid physical movement or displacement of the liquid. The volumetric liquid surge has a strong destructive power, and can cause a noncontact, remote injury in humans (such as blast-induced traumatic brain injury and post-traumatic stress disorder) if it is created in cardiovascular system. The hydraulic energy redirection and release technology can successfully mitigate blast shock waves from the outer surface of the body armor. It should be further explored as an innovative approach to effectively protect against blast threats to civilian and military personnel. PMID:22745740

  18. Output characteristics of high power pulsed electromagnetic wave generator for medical applications using water capacitor and water gap switch

    Microsoft Academic Search

    Y. Minamitani; Y. Ohe; T. Ueno; Y. Higashiyama

    2007-01-01

    Nanosecond and sub-nanosecond high voltage pulses can provide new applications. A cancer treatment by an ultra-short pulse high electric field is one of them. High power pulsed electromagnetic wave has been proposed to apply the high electric field for that treatment. This work focuses on the design of a compact high power pulsed electromagnetic wave generator using a nanosecond pulse

  19. Investigation of a Traveling-Wave Resonator for High-Power Component Testing for ITER

    NASA Astrophysics Data System (ADS)

    Fox, Bryan

    There is a need to test components at high-power and the high-power sources required to do this are very expensive. One way around this is to use a less-expensive, lower-power source and a traveling-wave resonator to test components at a power level several times that of the source. A traveling-wave resonator considered here consists of a diffraction grating and mirrors to reshape and refocus a beam. The resonator, however, may introduce complications like sensitivity to alignment, frequency and higher-order modes. In order to study the issues that may arise in using a traveling- wave resonator to test components at high-power, a resonator has been designed and simulated and the most important components have been fabricated and tested. The results of the measurements, simulation and design agree very well. An input mirror converting and refocusing a circular Gaussian beam to an elliptical Gaussian beam providing 97.9% complex vector coupling to the desired beam was designed and tested. Similarly, a refocusing mirror providing 99.6% coupling to the desired beam was designed and tested. The power coupled to a diffracted beam from a diffraction grating was simulated and measured with the results agreeing to 0.1 dB. With care, the complications in using a traveling-wave resonator to test components can be minimized. The total length of the resonator should be kept as short as possible to minimize frequency sensitivity. A resonator with 6.6 dB coupling to the diffracted beam and 0.5 dB loss can provide a power multiplication factor of 4 over a frequency range of 8 MHz if it is two meters in length, but only 2 MHz if it is 10 meters in length. Certain configurations where higher-order modes could resonate should also be avoided.

  20. Evidence of local power deposition and electron heating by a standing electromagnetic wave in electron-cyclotron-resonance plasma.

    PubMed

    Durocher-Jean, A; Stafford, L; Dap, S; Makasheva, K; Clergereaux, R

    2014-09-01

    Microwave plasmas excited at electron-cyclotron resonance were studied in the 0.5-15 mTorr pressure range. In contrast with low-limit pressure conditions where the plasma emission highlights a fairly homogeneous spatial structure, a periodic spatial modulation (period ?6.2 cm) appeared as pressure increased. This feature is ascribed to a local power deposition (related to the electron density) due to the presence of a standing electromagnetic wave created by the feed electromagnetic field (2.45 GHz) in the cavity formed by the reactor walls. Analysis of the electron energy probability function by Langmuir probe and optical emission spectroscopy further revealed the presence of a high-energy tail that showed strong periodic spatial modulation at higher pressure. The spatial evolution of the electron density and of the characteristic temperature of these high-energy electrons coincides with the nodes (maximum) and antinodes (minimum) of the standing wave. These spatially-modulated power deposition and electron heating mechanisms are then discussed. PMID:25314546

  1. 75 FR 21289 - Oregon Wave Energy Partners I, LLC; Notice of Preliminary Permit Application Accepted for Filing...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-04-23

    ...Project No. 12749-002] Oregon Wave Energy Partners I, LLC; Notice of Preliminary...2010. On March 2, 2010, Oregon Wave Energy Partners I, LLC filed an application...Charles F. Dunleavy, Oregon Wave Energy Partners I, LLC, 1590 Reed...

  2. Excitation of electrostatic ion cyclotron waves by a power-modulated transversely excited atmosphere (TEA) CO2 laser

    Microsoft Academic Search

    K. Sasaki; T. Fujii; K. Takahashi; M. Nagatsu; T. Tsukishima

    1993-01-01

    Electrostatic plasma waves are excited in a laboratory plasma by means of the ponderomotive force of a high-power, power-modulated transversely excited atmosphere (TEA) CO2 laser beam [W. W. Duley, CO2Lasers (Academic, New York, 1976), Chap. 2.5]. The strengths of the magnetic field, for which the plasma waves are excited selectively, and the group velocity of the excited plasma waves are

  3. An ocean kinetic energy converter for low-power applications using piezoelectric disk elements

    NASA Astrophysics Data System (ADS)

    Viñolo, C.; Toma, D.; Mànuel, A.; del Rio, J.

    2013-09-01

    The main problem facing long-term electronic system deployments in the sea, is to find a feasible way to supply them with the power they require. Harvesting mechanical energy from the ocean wave oscillations and converting it into electrical energy, provides an alternative method for creating self-contained power sources. However, the very low and varying frequency of ocean waves, which generally varies from 0.1 Hz to 2 Hz, presents a hurdle which has to be overcome if this mechanical energy is to be harvested. In this paper, a new sea wave kinetic energy converter is described using low-cost disk piezoelectric elements, which has no dependence on their excitement frequency, to feed low-consumption maritime-deployed electronic devices. The operating principles of the piezoelectric device technique are presented, including analytical formulations describing the transfer of energy. Finally, a prototypical design, which generates electrical energy from the motion of a buoy, is introduced. The paper concludes with the the behavior study of the piezoelectric prototype device as a power generator.

  4. Apparatus for producing electrical energy from ocean waves

    SciTech Connect

    Ng, T.F.

    1981-05-05

    An energy conversion device is disclosed which utilizes the natural movements of ocean waves to produce electrical energy. The apparatus is contained in a tank which is adapted to float near the surface of the water and tilt from side to side about a pivot point located below the tank, thereby simulating a pendulum -like movement. A sinker weight is employed to produce the appropriate movement of the tank and maintain the floating tank in balance at the ocean surface. The pendulum motion of the tank is used to roll a plurality of gravity wheels or their respective horizontal platforms in the tank in such manner that shafts associated with the gravity wheels are caused to rotate. Electrical generators are operatively connected to the rotating shafts for producing electrical energy from the mechanical rotative energy of the shafts as the tank tilts from side to side with the wave motion. Each gravity wheel is equipped with a ratchet-like lock which prevents backward motion of the wheel such that it rolls in a single direction in a circular path on the platform. While one or more gravity wheels have their locks set so the wheels roll only in a clockwise direction, other gravity wheels are free to roll only in a counterclockwise direction. In this fashion, when the tank tilts to one side due to the rise of an ocean wave the gravity wheels roll from the higher side of their respective platforms to the lower sides along their prescribed circular paths. The centrifugal force generated by the weight of the gravity wheels and the unceasing action of the ocean waves provides the continuous generation of electrical energy.

  5. Radiant Energy Power Source for Jet Aircraft

    SciTech Connect

    Doellner, O.L.

    1992-02-01

    This report beings with a historical overview on the origin and early beginnings of Radiant Energy Power Source for Jet Aircraft. The report reviews the work done in Phase I (Grant DE-FG01-82CE-15144) and then gives a discussion of Phase II (Grant DE-FG01-86CE-15301). Included is a reasonably detailed discussion of photovoltaic cells and the research and development needed in this area. The report closes with a historical perspective and summary related to situations historically encountered on projects of this nature. 15 refs.

  6. Energy and power limits for microbial activity

    NASA Astrophysics Data System (ADS)

    LaRowe, D.; Amend, J.

    2014-12-01

    The goal of this presentation is to describe a quantitative framework for determining how energy limits microbial activity, biomass and, ultimately, biogeochemical processes. Although this model can be applied to any environment, its utility is demonstrated in marine sediments, which are an attractive test habitat because they encompass a broad spectrum of energy levels, varying amounts of biomass and are ubiquitous. The potential number of active microbial cells in Arkonas Basin (Baltic Sea) sediments are estimated as a function of depth by quantifying the amount of energy that is available to them and the rate at which it is supplied: power. The amount of power supplied per cubic centimeter of sediment is determined by calculating the Gibbs energy of fermentation and sulfate reduction in combination with the rate of particulate organic carbon, POC, degradation. The Reactive Continuum Model (Boudreau and Ruddick, 1991), RCM, is used to determine the rate at which POC is made available for microbial consumption. The RCM represents POC as containing a range of different types of organic compounds whose ability to be consumed by microorganisms varies as a function of the age of the sediment and on the distribution of compound types that were initially deposited. The sediment age model and RCM parameters determined by (Mogollon et al., 2012) are used. The power available for fermentation and sulfate reduction coupled to H2 and acetate oxidation varies from 10-8 W cm-3 at the sediment water interface to between 10-11 - 10-12 W cm-3 at 3.5 meters below the seafloor, mbsf. Using values of maintenance powers for each of these catabolic activities taken from the literature, the total number of active cells in these sediments similarly decreases from just less than 108 cell cm-3 at the SWI to 4.6 x 104 cells cm-3 at 3.5 mbsf. The number of moles of POC decreases from 2.6 x 10-5 to 9.5 x 10-6, also becoming more recalcitrant with depth. Boudreau, B. P. and Ruddick, B. R. (1991) On a reactive continuum representation of organic matter diagenesis. Amer. J. Sci. 291, 507-538. Mogollon, J. M., Dale, A. W., Fossing, H. and Regnier, P. (2012) Timescales for the development of methanogenesis and free gas layers in recently-deposited sediments of Arkona Bason (Baltic Sea). Biogeosciences 9, 1915-1933.

  7. Using an electrooptic modulator to stabilize the power of a continuous-wave laser

    SciTech Connect

    Bikmukhametov, K.A.; Kiryunikov, K.V.

    1986-01-01

    The authors present results from using an electrooptic modulator as a control component in an external power stabilization system for a continuous-wave laser. The power stability and reproducibility in a helium-neon laser type LG-75 working with this device are restricted by the stability and reproducibility in the voltage level from the reference source and by the photocell transfer coefficient, as well as by the stabilizer bandwidth. The limits to the regulation of the power based on adjusting the reference voltage for a constant are limited by the contrast coefficient in the electrooptic modulator.

  8. Loops of Energy Bands for Bloch Waves in Optical Lattices By Matt Coles and Dmitry Pelinovsky

    E-print Network

    Pelinovsky, Dmitry

    Loops of Energy Bands for Bloch Waves in Optical Lattices By Matt Coles and Dmitry Pelinovsky We in this context. These bifurcations generate loops in the energy bands of the Bloch waves near the ends is the possibility of loops in the energy bands associated with the nonlinear Bloch waves. This possibility was first

  9. Numerical modeling of extreme rogue waves generated by directional energy focusing

    E-print Network

    Grilli, Stéphan T.

    Numerical modeling of extreme rogue waves generated by directional energy focusing Christophe angle of directional energy focusing. We find that an over- turning rogue wave can have different are characterized by their brief occurrence in space and time, resulting from a local focusing of wave energy

  10. Optimization of quantum Monte Carlo wave functions using analytical energy derivatives

    E-print Network

    Lin, Xi

    Optimization of quantum Monte Carlo wave functions using analytical energy derivatives Xi Lin of the local energy, H^ / .5 If the wave function were the exact ground eigenstate, the local energy would November 1999 An algorithm is proposed to optimize quantum Monte Carlo QMC wave functions based on Newton

  11. Surface current effects on the fetch-limited growth of wave energy Brian K. Haus1

    E-print Network

    Miami, University of

    Surface current effects on the fetch-limited growth of wave energy Brian K. Haus1 Received 5 the fetch-limited growth of wind wave energy over a region with significant lateral shear of the current. Both the near-surface currents and wave energy and period were mapped over the highly sheared inshore

  12. Development of a Wireless Control and Monitoring System for Wave Energy Converters

    E-print Network

    Wood, Stephen L.

    Development of a Wireless Control and Monitoring System for Wave Energy Converters Ismail Sultan Control and Monitoring Unit (PCMU) for the design and performance evaluation of wave energy converters (WECs). A prototype PCMU system was successfully deployed on June 8th , 2012 with wave energy convertor

  13. Free energy in plasmas under wave-induced diffusion Nathaniel J. Fish

    E-print Network

    Free energy in plasmas under wave-induced diffusion Nathaniel J. Fish Princeton Plasma Physics of the plasma kinetic energy. In many cases of interest, the primary effect of the wave is to cause plasma extractable energy by waves so diffusing the plasma is a quantity of fundamental interest; it can be defined

  14. Model-predicted distribution of wind-induced internal wave energy in the world's oceans

    E-print Network

    Miami, University of

    Model-predicted distribution of wind-induced internal wave energy in the world's oceans Naoki 9 July 2008; published 30 September 2008. [1] The distribution of wind-induced internal wave energy-induced internal wave energy in the world's oceans, J. Geophys. Res., 113, C09034, doi:10.1029/2008JC004768. 1

  15. Physics 5B Winter 2009 Rate of Energy Transfer by Sinusoidal Waves on a String

    E-print Network

    California at Santa Cruz, University of

    Physics 5B Winter 2009 Rate of Energy Transfer by Sinusoidal Waves on a String Consider a sinusoidal wave traveling along the x­axis on a stretched string. Focus on the in­ finitesimal segment the kinetic energy and the potential energy of this string segment due to the passage of a traveling wave

  16. Physics 5B Winter 2009 Rate of Energy Transfer by Sinusoidal Waves on a String

    E-print Network

    California at Santa Cruz, University of

    Physics 5B Winter 2009 Rate of Energy Transfer by Sinusoidal Waves on a String Consider a sinusoidal wave traveling along the x-axis on a stretched string. Focus on the in- finitesimal segment the kinetic energy and the potential energy of this string segment due to the passage of a traveling wave

  17. Electric power processing, distribution, management and energy storage

    NASA Technical Reports Server (NTRS)

    Giudici, R. J.

    1980-01-01

    Power distribution subsystems are required for three elements of the SPS program: (1) orbiting satellite, (2) ground rectenna, and (3) Electric Orbiting Transfer Vehicle (EOTV). Power distribution subsystems receive electrical power from the energy conversion subsystem and provide the power busses rotary power transfer devices, switchgear, power processing, energy storage, and power management required to deliver control, high voltage plasma interactions, electric thruster interactions, and spacecraft charging of the SPS and the EOTV are also included as part of the power distribution subsystem design.

  18. An experimental investigation of a tandem relativistic backward wave oscillator-travelling wave tube amplifier system for generating high-power microwaves

    Microsoft Academic Search

    Gilberto Barreto

    1992-01-01

    The experimental investigation described in this dissertation demonstrates the feasibility of generating long (greater than or equal to 50 nsec) pulses of high-power (greater than or equal to 100 MW), X-band frequency microwaves. In these experiments, a relativistic Backward Wave Oscillator (BWO) is used in tandem with a Traveling Wave Tube (TWT) amplifier to generate microwave radiation. The tandem BWO

  19. The Ubitron, a high-power traveling-wave tube based on a periodic beam interaction in unloaded waveguide

    Microsoft Academic Search

    R. M. Phillips

    1960-01-01

    The Ubitron is a high-power traveling-wave tube which makes use of the interaction between a magnetically undulated periodic electron beam and the TE01mode in unloaded waveguide. The electron-wave interaction exhibits the same type of first-order axial beam bunching characteristic of the conventional slow-wave traveling-wave tube; hence, it can be used in place of conventional O-type interaction in extended interaction klystrons

  20. Technical options for high average power free electron milimeter-wave and laser devices

    NASA Technical Reports Server (NTRS)

    Swingle, James C.

    1989-01-01

    Many of the potential space power beaming applications require the generation of directed energy beams with respectable amounts of average power (MWs). A tutorial summary is provided here on recent advances in the laboratory aimed at producing direct conversion of electrical energy to electromagnetic radiation over a wide spectral regime from microwaves to the ultraviolet.

  1. Resistor Emulation Approach to Low-Power RF Energy Harvesting

    Microsoft Academic Search

    Thurein Paing; Jason Shin; Regan Zane; Zoya Popovic

    2008-01-01

    This paper presents an approach and associated circuitry for harvesting near maximum output power from electromagnetic waves in the RF\\/microwave region of the spectrum with variable incident power densities in the range of tens of muW\\/cm2. It is shown that open loop resistor emulation at the input port of a power converter is a suitable solution for tracking the peak

  2. OWC wave energy devices with air flow control

    Microsoft Academic Search

    A. F. de O. Falcão; P. A. P. Justino

    1999-01-01

    A theoretical model is developed to simulate the energy conversion, from wave to turbine shaft, of an oscillating-water-column (OWC) plant equipped with a Wells air-turbine and with a valve (in series or in parallel with the turbine) for air-flow control. Numerical simulations show that the use of a control valve, by preventing or reducing the aerodynamic stall losses at the

  3. Zero-energy wave packets that follow classical orbits

    NASA Astrophysics Data System (ADS)

    Makowski, Adam J.; Pep?owski, Piotr

    2012-10-01

    Coherent states for a large class of the Lenz-Demkov-Ostrovsky (LDO) potentials are constructed as superpositions of zero-energy Hamiltonian eigenstates. They represent very well-localized stationary wave packets. Moreover, it is shown how to make the packets move along suitable classical orbits. The calculations are performed for a few members of the LDO family of potentials, among them, for the Maxwell's fish-eye model and that used for a theoretical explanation of the periodic system of elements.

  4. Propagation-invariant wave fields with finite energy

    Microsoft Academic Search

    Rafael Piestun; Yoav Y. Schechner; Joseph Shamir

    2000-01-01

    Propagation invariance is extended in the paraxial regime, leading to a generalized self-imaging effect. These wave fields are characterized by a finite number of transverse self-images that appear, in general, at different orientations and scales. They possess finite energy and thus can be accurately generated. Necessary and sufficient conditions are derived, and they are appropriately represented in the Gauss-Laguerre modal

  5. Economical considerations of renewable electric energy production—especially development of wave energy

    Microsoft Academic Search

    Mats Leijon; Hans Bernhoff; Marcus Berg; Olov Ågren

    2003-01-01

    Investments in renewable energy plants normally only take standard economic key figures into account, such as installed rated power, the market price of energy and the interest rate. The authors propose that the degree of utilisation, i.e. the ratio of yearly produced energy in the installation to the installed power, must be included due to its significant impact on the

  6. Smart electrical energy storage system for small power wind turbines

    Microsoft Academic Search

    M. Georgescu; L. Barote; C. Marinescu; L. Clotea

    2010-01-01

    Energy storage devices and solutions are required for power quality and balance within wind systems. In the context of rapidly expanding of distributed energy sources, the wind energy converters are in the center of interest. In this case, the direct dependence of the power generation capability for a given wind speed represents a major problem of wind energy conversion with

  7. Local energy function methods for power system transient stability

    Microsoft Academic Search

    Rastgoufard

    1983-01-01

    Energy function, the first integral of the accelerating power equation, is used to investigate the problem of power system transient stability. In contrast to the total system (global) energy function, the partial (local) energy function, which is the energy existing between and within an accelerated and a stationary group of generators, is considered in the analysis. Based on simulation, it

  8. Wind Power Today: 2000 Wind Energy Program Highlights

    Microsoft Academic Search

    Weis-Taylor

    2001-01-01

    Wind Power Today is an annual publication that provides an overview of the U.S. Department of Energy's Wind Energy Program. The purpose of Wind Power Today is to show how DOE's Wind Energy Program supports wind turbine research and deployment in hopes of furthering the advancement of wind technologies that produce clean, low-cost, reliable energy. Content objectives include: educate readers

  9. Wind power today: 1999 Wind Energy program highlights

    Microsoft Academic Search

    Weis-Taylor

    2000-01-01

    Wind Power Today is an annual publication that provides an overview for the Department of Energy's Wind Energy Program. The purpose of Wind Power Today is to show how DOE's Wind Energy Program supports wind turbine research and deployment in hopes of furthering the advancement of wind technologies that produce clean, low-cost, reliable energy for the 21st century. Content objectives

  10. Power Allocation for Energy Harvesting Transmitter with Causal Information

    E-print Network

    Greenberg, Albert

    1 Power Allocation for Energy Harvesting Transmitter with Causal Information Zhe Wang, Vaneet- controlled transmitter with energy harvesting capability based on causal observations of the channel fading powered by a renewable energy source and the energy harvesting process can practically be predicted

  11. Networking Low-Power Energy Harvesting Devices: Measurements and Algorithms

    E-print Network

    Shepard, Kenneth

    Networking Low-Power Energy Harvesting Devices: Measurements and Algorithms Maria Gorlatova, Aya--Recent advances in energy harvesting materials and ultra-low-power communications will soon enable the realization of networks composed of energy harvesting devices. These devices will operate using very low ambient energy

  12. Market potential of renewable energy powered desalination systems in Greece

    Microsoft Academic Search

    D. Voivontas; K. Yannopoulos; K. Rados; A. Zervos; D. Assimacopoulos

    1999-01-01

    The present work analyzes water management strategies based on advanced desalination schemes powered by renewable energy sources. The framework for developing a decision procedure, which monitors water shortage problems and identifies the availability of renewable energy resources to power desalination plants, is presented. Cost of alternative solutions, taking into account energy cost or profits by energy selling to grid, is

  13. The Time Domain Method for Power Line Reactive Energy Measurement

    Microsoft Academic Search

    Bogdan Spasojevic

    2007-01-01

    This paper introduces the idea that reactive energy is a measure of exchange of energy between the generator and the reactance of load within one period of instantaneous power. A measure of energy exchange within one power period is defined as the value proportional to the classic reactive energy definition. The factor of proportionality is . The new concept provides

  14. Wave equations for determining energy-level gaps of quantum systems

    E-print Network

    Zeqian Chen

    2006-09-10

    An differential equation for wave functions is proposed, which is equivalent to Schr\\"{o}dinger's wave equation and can be used to determine energy-level gaps of quantum systems. Contrary to Schr\\"{o}dinger's wave equation, this equation is on `bipartite' wave functions. It is shown that those `bipartite' wave functions satisfy all the basic properties of Schr\\"{o}dinger's wave functions. Further, it is argued that `bipartite' wave functions can present a mathematical expression of wave-particle duality. This provides an alternative approach to the mathematical formalism of quantum mechanics.

  15. Beamed-Energy Propulsion (BEP): Considerations for Beaming High Energy-Density Electromagnetic Waves Through the Atmosphere

    NASA Technical Reports Server (NTRS)

    Manning, Robert M.

    2015-01-01

    A study to determine the feasibility of employing beamed electromagnetic energy for vehicle propulsion within and outside the Earth's atmosphere was co-funded by NASA and the Defense Advanced Research Projects Agency that began in June 2010 and culminated in a Summary Presentation in April 2011. A detailed report entitled "Beamed-Energy Propulsion (BEP) Study" appeared in February 2012 as NASA/TM-2012-217014. Of the very many nuances of this subject that were addressed in this report, the effects of transferring the required high energy-density electromagnetic fields through the atmosphere were discussed. However, due to the limitations of the length of the report, only a summary of the results of the detailed analyses were able to be included. It is the intent of the present work to make available the complete analytical modeling work that was done for the BEP project with regard to electromagnetic wave propagation issues. In particular, the present technical memorandum contains two documents that were prepared in 2011. The first one, entitled "Effects of Beaming Energy Through the Atmosphere" contains an overview of the analysis of the nonlinear problem inherent with the transfer of large amounts of energy through the atmosphere that gives rise to thermally-induced changes in the refractive index; application is then made to specific beamed propulsion scenarios. A brief portion of this report appeared as Appendix G of the 2012 Technical Memorandum. The second report, entitled "An Analytical Assessment of the Thermal Blooming Effects on the Propagation of Optical and Millimeter- Wave Focused Beam Waves For Power Beaming Applications" was written in October 2010 (not previously published), provides a more detailed treatment of the propagation problem and its effect on the overall characteristics of the beam such as its deflection as well as its radius. Comparisons are then made for power beaming using the disparate electromagnetic wavelengths of 1.06 microns and 2.0 millimeters..

  16. Waveguide Power Combiner Demonstration for Multiple High Power Millimeter Wave TWTAs

    NASA Technical Reports Server (NTRS)

    Wintucky, Edwin G.; Simons, Rainee N.; Lesny, Gary G.; Glass, Jeffrey L.

    2004-01-01

    NASA is presently developing nuclear reactor technologies, under Project Prometheus, which will provide spacecraft with greatly increased levels of sustained onboard power and thereby dramatically enhance the capability for future deep space exploration. The first mission planned for use of this high power technology is the Jupiter Icy Moons Orbiter (JIMO). In addition to electric propulsion and science, there will also be unprecedented onboard power available for deep space communications. A 32 GHz transmitter with 1 kW of RF output power is being considered to enable the required very high data transmission rates. One approach to achieving the 1 kW RF power, now being investigated at NASA GRC, is the possible power combining of a number of 100-1 50 W TWTs now under development. The work presented here is the results of a proof-of-concept demonstration of the power combining Ka-band waveguide circuit design and test procedure using two Ka- band TWTAs (Varian model VZA6902V3 and Logimetrics model A440/KA-1066), both of which were previously employed in data uplink evaluation terminals at 29.36 GHz for the NASA Advanced Communications Technology Satellite (ACTS) program. The characterization of the individual TWTAs and power combining demonstration were done over a 500 MHz bandwidth from 29.1 to 29.6 GHz to simulate the Deep Space Network (DSN) bandwidth of 3 1.8 to 32.3 GHz. Figures 1-3 show some of the power transfer and gain measurements of the TWTAs using a swept signal generator (Agilent 83640b) for the RF input. The input and output powers were corrected for circuit insertion losses due to the waveguide components. The RF saturated powers of both ACTS TWTAs were on the order of 120 W, which is comparable to the expected output powers of the 32 GHz TWTs. Additional results for the individual TWTAs will be presented (AM/AM, AM/PM conversion and gain compression), some of which were obtained from swept frequency and power measurements using a vector network analyzer. The results for the power combining demonstration as well as a more detailed description of the power combining test circuit and test procedure will also be presented.

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

    PubMed

    Billat, Adrien; Cordette, Steevy; Tseng, Yu-Pei; Kharitonov, Svyatoslav; Brès, Camille-Sophie

    2014-06-16

    We report the design of an all-fiber continuous wave Short-Wave Infrared source capable to output up to 700 mW of power at 1940 nm. The source is tunable over wavelength intervals comprised between 1850 nm and 2070 nm depending on its configuration. The output can be single or multimode while the optical signal to noise ratio ranges from 25 and 40 dB. The architecture is based on the integrated association of a fiber optical parametric amplifier and a Thulium doped fiber amplifier. PMID:24977531

  18. O the Propagation of Frequencies and Energy in Certain Types of Oceanic and Atmospheric Waves

    Microsoft Academic Search

    C.-G. Rossby

    1945-01-01

    In this paper the energy and frequency propagation in certain types of plane waves in the atmosphere and in the ocean are investigated, these wave trains being characterized by the property that frequency and wave number are slowly varying functions of the space coordinate and time.The assumption is made that wave crests are conserved, and on this basis a simple

  19. APRIL 2006 MOUM ET. AL. 1 Energy Transport by Nonlinear Internal Waves

    E-print Network

    APRIL 2006 MOUM ET. AL. 1 Energy Transport by Nonlinear Internal Waves J. N. MOUM1 , J. M. KLYMAK2 internal waves propagate. Shipboard profiling and bottom lander observations capture disturbances that exhibit properties of internal solitary waves, bores and gravity currents. Wave-like pulses are highly

  20. Estimating Internal Wave Energy Fluxes in the Ocean JONATHAN D. NASH

    E-print Network

    Kurapov, Alexander

    Estimating Internal Wave Energy Fluxes in the Ocean JONATHAN D. NASH College of Oceanic internal wave generation, propagation, and dissipation. In this paper, the estimation of internal wave. Sampling must be sufficient in depth to allow for the estimation of the internal wave­induced pressure

  1. SEPTEMBER 2006 MOUM ET. AL. 1 Energy Transport by Nonlinear Internal Waves

    E-print Network

    SEPTEMBER 2006 MOUM ET. AL. 1 Energy Transport by Nonlinear Internal Waves J. N. MOUM1 , J. M which nonlinear internal waves propagate. Shipboard profiling and bottom lander observations capture disturbances that exhibit properties of internal solitary waves, bores and gravity currents. Wave-like pulses

  2. Nonhydrostatic and nonlinear contributions to the energy flux budget in nonlinear internal waves

    E-print Network

    Fringer, Oliver B.

    Nonhydrostatic and nonlinear contributions to the energy flux budget in nonlinear internal waves S and evolution of nonlinear internal waves formed as a result of the interaction of a first-mode internal wave are significant in these large nonlinear internal waves, consistent with recent field observations. Citation

  3. Fine scale inhomogeneity of wind-wave energy input, skewness, and asymmetry

    Microsoft Academic Search

    Yehuda Agnon; Alex V. Babanin; Ian R. Young; Dmitry Chalikov

    2005-01-01

    Analysis of measured sea and lake wind wave data reveals large variability of the wind energy input, as well as the waves skewness and asymmetry. The spatial and temporal third moments alternate in sign over a few wave periods and over a few wavelengths, respectively. Simulation through a 2D Wave Boundary Layer model in which the air flow is modeled

  4. Modeling radiation belt radial diffusion in ULF wave fields: 1. Quantifying ULF wave power at geosynchronous orbit in observations and in global MHD model

    NASA Astrophysics Data System (ADS)

    Huang, Chia-Lin; Spence, Harlan E.; Singer, Howard J.; Hughes, W. Jeffrey

    2010-06-01

    To provide critical ULF wave field information for radial diffusion studies in the radiation belts, we quantify ULF wave power (f = 0.5-8.3 mHz) in GOES observations and magnetic field predictions from a global magnetospheric model. A statistical study of 9 years of GOES data reveals the wave local time distribution and power at geosynchronous orbit in field-aligned coordinates as functions of wave frequency, solar wind conditions (Vx, ?Pd and IMF Bz) and geomagnetic activity levels (Kp, Dst and AE). ULF wave power grows monotonically with increasing solar wind Vx, dynamic pressure variations ?Pd and geomagnetic indices in a highly correlated way. During intervals of northward and southward IMF Bz, wave activity concentrates on the dayside and nightside sectors, respectively, due to different wave generation mechanisms in primarily open and closed magnetospheric configurations. Since global magnetospheric models have recently been used to trace particles in radiation belt studies, it is important to quantify the wave predictions of these models at frequencies relevant to electron dynamics (mHz range). Using 27 days of real interplanetary conditions as model inputs, we examine the ULF wave predictions modeled by the Lyon-Fedder-Mobarry magnetohydrodynamic code. The LFM code does well at reproducing, in a statistical sense, the ULF waves observed by GOES. This suggests that the LFM code is capable of modeling variability in the magnetosphere on ULF time scales during typical conditions. The code provides a long-missing wave field model needed to quantify the interaction of radiation belt electrons with realistic, global ULF waves throughout the inner magnetosphere.

  5. Power combining techniques for RF and mm-wave CMOS power amplifiers

    Microsoft Academic Search

    P. Reynaert; A. M. Niknejad

    2007-01-01

    An overview of several CMOS RF Power Amplifiers (PA) using power combining techniques is given. It is clarified how this technique can alleviate some of the problems related to the aggressive CMOS scaling. The theory is supported by several design examples that cover a frequency range from the lower GHz as high as 60 GHz.

  6. Abstract--Wave energy will have a key role in meeting re-newable energy targets en route to a low carbon economy. How-

    E-print Network

    Harrison, Gareth

    1 Abstract--Wave energy will have a key role in meeting re- newable energy targets en route will impact on wave energy conversion. Where the resource is restricted there may be reductions in energy the sensitivity of wave energy production and econom- ics to changes in climate. Index Terms--Wave energy

  7. High Energy Gravitational Waves from the Early Universe

    NASA Astrophysics Data System (ADS)

    Dolgov, A. D.

    2014-03-01

    Emission of gravitational waves (GW) in the early universe by light primordial black holes(PBH) is considered. It is supposed that PBHs dominated in the cosmological energy density at some early stage of the cosmological history. At this stage previously existed relics (including GWs from inflation) could be diluted and the new radiation dominated era emerged after the PBH evaporation. GWs produced by the PBH interactions and evaporation would have very high energy, 1-100 keV, which is far outside the sensitivity range of the traditional GW detectors. A possibility of observation of such energetic GWs through graviton-to-photon transition in external magnetic field is discussed.

  8. Comparison of low-power single-stage boost rectifiers for sub-milliwatt electromagnetic energy harvesters

    NASA Astrophysics Data System (ADS)

    Szarka, Gyorgy D.; Proynov, Plamen P.; Stark, Bernard H.; Burrow, Stephen G.

    2013-05-01

    Energy harvesting could provide power-autonomy to many important embedded sensing application areas. However, the available envelope often limits the power output, and also voltage levels. This paper presents the implementation of an enabling technology for space-restricted energy harvesting: Four highly efficient and fully autonomous power conditioning circuits are presented that are able to operate at deep-sub-milliwatt input power at less than 1 Vpk AC input, and provide a regulated output voltage. The four complete systems, implemented using discrete components, include the power converters, the corresponding ancillary circuits with sub-10 ?W consumption, start-up circuit, and an ultra-lowpower shunt regulator with under-voltage lockout for the management of the accumulated energy. The systems differ in their power converter topology; all are boost rectifier variants that rectify and boost the generator's output in a single stage, that are selected to enable direct comparison between polarity-dependent and -independent, as well as between full-wave and half-wave power converter systems. Experimental results are derived over a range of 200-1200 ?W harvester output power, the system being powered solely by the harvester. Experimental results show overall conversion efficiency, accounting for the quiescent power consumption, as high as 82% at 650 ?W input, which remains in the 65-70% range even at 200 ?W input for the half-wave variant. Harvester utilisation of over 90% is demonstrated in the sub-milliwatt range using full-wave topologies. For the evaluated generator, the full-wave, polarity-dependent boost rectifier offers the best overall system effectiveness, achieving up to 73% of the maximum extractable power.

  9. Numerical studies of powerful terahertz pulse generation from a super-radiant surface wave oscillator

    SciTech Connect

    Zhang Hai [Key Laboratory of Physical Electronics and Devices of the Ministry of Education, Xi'an Jiaotong University, Xi'an, Shaanxi 710049 (China); Wang Jianguo [Key Laboratory of Physical Electronics and Devices of the Ministry of Education, Xi'an Jiaotong University, Xi'an, Shaanxi 710049 (China); Northwest Institute of Nuclear Technology, P.O. Box 69-12, Xi'an, Shaanxi 710024 (China); Tong Changjiang; Li Xiaoze [Northwest Institute of Nuclear Technology, P.O. Box 69-12, Xi'an, Shaanxi 710024 (China); Wang Guangqiang [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China)

    2009-12-15

    The results of theoretical and numerical studies of coherent stimulated terahertz radiation from intense, subnanosecond electron beam are presented. The mechanism of terahertz pulse generation is associated with self-bunching of the beam and slippage of the wave over the whole electron flow. This so called Cherenkov super-radiance (SR) is used to propose a compact terahertz generator with high peak power. A large cross-section (overmoded), slow wave structure is designed to support the high power handling capability, and the mode competition is avoided by operating the device in the surface wave status. With 2.5 D particle-in-cell simulation, the 'hot' characteristics of the proposed super-radiant terahertz generator are investigated, and the numerical results show that the SR peak power could be further increased by optimizing the amplitude profile of electron pulse. Under the condition of 0.5 ns pulsewidth, 500 kV voltage, and 1.5 kA current, the 110 ps, 680 MW, and 0.14 THz SR pulse is achieved with a power efficiency of 90.67% in TM{sub 01} mode.

  10. The Effects of Wave Energy Converters on a Monochromatic Wave Climate

    E-print Network

    Fox-Kemper, Baylor

    assumed to perform at optimal efficiency as estimated by Previsic and Bedard [2007]. The size and shape has an ideal energy density of 1 kW hr/m2 [Previsic & Bedard 2007]. Figure 1 shows the distribution distribution and potential power density according to Previsic & Bedard, [2007]. #12;The Effects of a WEC

  11. 75 FR 29531 - Resale Power Group of Iowa, WPPI Energy v. ITC Midwest LLC, Interstate Power and Light Company...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-05-26

    ...EL10-68-000] Resale Power Group of Iowa, WPPI Energy v...Interstate Power and Light Company; Notice of Complaint May...2006), Resale Power Group of Iowa and WPPI Energy...Interstate Power and Light Company (Respondents),...

  12. Design considerations for energy storage power electronics interfaces for high penetration of renewable energy sources

    Microsoft Academic Search

    Junseok Song; Ruichen Zhao; Alexis Kwasinski

    2011-01-01

    This paper discusses design considerations of power electronics interfaces between renewable energy sources and energy storage. When renewable energy sources—including photovoltaic modules, wind generators, and fuel cells—are used to generate power, there are certain electrical properties of each source that need to be considered for the design of energy storage power electronics interface. In addition, energy storage's charging and discharging

  13. Improving communication energy efficiency in wireless networks powered by Renewable energy sources

    Microsoft Academic Search

    Fan Zhang; Samuel T. Chanson

    2005-01-01

    Energy efficiency is an important issue in wireless networks where the nodes are powered by batteries. In this work, we analyze the energy consumption in one-transmitter-multiple-receiver communication and develop scheduling schemes to improve energy efficiency at the transmitter. Our focus is on systems powered by a renewable energy source such as solar power. We consider an environment where both energy

  14. Benefits of Power Electronic Interfaces for Distributed Energy Systems

    Microsoft Academic Search

    Benjamin Kroposki; Christopher Pink; Richard DeBlasio; Holly Thomas; Marcelo Simões; Pankaj K. Sen

    2010-01-01

    With the increasing use of distributed energy (DE) systems in industry and its technological advancement, it is becoming more important to understand the integration of these systems with the electric power systems. New markets and benefits for DE applications include the ability to provide ancillary services, improve energy efficiency, enhance power system reliability, and allow customer choice. Advanced power electronic

  15. Contribution to the Chapter on Wind Power Energy Technology

    E-print Network

    Contribution to the Chapter on Wind Power Energy Technology Perspectives 2008 Jørgen Lemming; Poul in the wind energy sector. As a result, better electrical grids suited for wind power are being developed&D areas to foster continued growth in wind power are to increase the value and reduce uncertainties

  16. Analysis of power output for piezoelectric energy harvesting systems

    Microsoft Academic Search

    Y C Shu; I C Lien

    2006-01-01

    Power harvesting refers to the practice of acquiring energy from the environment which would be otherwise wasted and converting it into usable electric energy. Much work has been done on studying the optimal AC power output, while little has considered the AC–DC output. This article investigates the optimal AC–DC power generation for a rectified piezoelectric device. In contrast with estimates

  17. Analysis of power output for piezoelectric energy harvesting systems

    Microsoft Academic Search

    Y. C. Shu; I. C. Lien

    2006-01-01

    Power harvesting refers to the practice of acquiring energy from the environment which would be otherwise wasted and converting it into usable electric energy. Much work has been done on studying the optimal AC power output, while little has considered the AC-DC output. This article investigates the optimal AC-DC power generation for a rectified piezoelectric device. In contrast with estimates

  18. Active and reactive power in stochastic resonance for energy harvesting

    E-print Network

    Kubota, Madoka; Hikihara, Takashi

    2015-01-01

    A power allocation to active and reactive power in stochastic resonance is discussed for energy harvesting from mechanical noise. It is confirmed that active power can be increased at stochastic resonance, in the same way of the relationship between energy and phase at an appropriate setting in resonance.

  19. Research on flywheel energy storage system for power quality

    Microsoft Academic Search

    Zhang Jiancheng; Huang Lipei; Chen Zhiye; Wu Su

    2002-01-01

    This paper presents a design of flywheel energy storage (FES) system in power network, which is composed of four parts: (1) the flywheel that stores energy, (2) the bearing that supports the flywheel, (3) the asynchronous motor\\/generator, and (4) the AC power converter regulated by a microprocessor controller. The control methods and strategy of the FES system for power quality

  20. Wave energy utilization into ship propulsion by fins attached to a ship

    SciTech Connect

    Isshiki, H. [Hitachi Zosen Corp., Osaka (Japan)

    1994-12-31

    Resistance of a ship increases in waves, that is, so called resistance increase of a ship due to waves. However, an oscillatory hydrofoil attached to the ship bow generates thrust. Under a certain condition, the ship can be driven by wave power alone. This paper reviews the design and performance of such a system.