Science.gov

Sample records for wave energy power

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

    SciTech Connect

    Mekhiche, Mike; Dufera, Hiz; Montagna, Deb

    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.

  2. 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

  3. 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, ...

  4. Energy Flux in the Cochlea: Evidence Against Power Amplification of the Traveling Wave.

    PubMed

    van der Heijden, Marcel; Versteegh, Corstiaen P C

    2015-10-01

    Traveling waves in the inner ear exhibit an amplitude peak that shifts with frequency. The peaking is commonly believed to rely on motile processes that amplify the wave by inserting energy. We recorded the vibrations at adjacent positions on the basilar membrane in sensitive gerbil cochleae and tested the putative power amplification in two ways. First, we determined the energy flux of the traveling wave at its peak and compared it to the acoustic power entering the ear, thereby obtaining the net cochlear power gain. For soft sounds, the energy flux at the peak was 1?±?0.6 dB less than the middle ear input power. For more intense sounds, increasingly smaller fractions of the acoustic power actually reached the peak region. Thus, we found no net power amplification of soft sounds and a strong net attenuation of intense sounds. Second, we analyzed local wave propagation on the basilar membrane. We found that the waves slowed down abruptly when approaching their peak, causing an energy densification that quantitatively matched the amplitude peaking, similar to the growth of sea waves approaching the beach. Thus, we found no local power amplification of soft sounds and strong local attenuation of intense sounds. The most parsimonious interpretation of these findings is that cochlear sensitivity is not realized by amplifying acoustic energy, but by spatially focusing it, and that dynamic compression is realized by adjusting the amount of dissipation to sound intensity. PMID:26148491

  5. Dielectric elastomer energy harvesting: maximal converted energy, viscoelastic dissipation and a wave power generator

    NASA Astrophysics Data System (ADS)

    Lv, Xiongfei; Liu, Liwu; Liu, Yanju; Leng, Jinsong

    2015-11-01

    Dielectric elastomer (DE) is a smart soft material. It is able to produce large deformation under mechanical force and electric field, so that it can achieve mutual conversion between mechanical energy and electrical energy. Based on this property, dielectric elastomer can be used in energy harvesting field. In this paper, firstly, we analyzed the constitutive relation under different hyperelastic models (Gent and neo-Hookean model) based on both theoretical and experimental study. Secondly, we depicted the allowable areas in force-displacement and voltage-charge plane according to different failure modes, and then calculated the maximal energy density in one energy harvesting period. Thirdly, we studied the viscoelastic energy dissipation which can lose the input mechanical energy in the energy harvesting process. Finally, we designed and fabricated a wave power generator, and tested its performance. This paper is of deep significance to the future applications of DE generators.

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

    SciTech Connect

    Hart, Philip R.

    2011-09-27

    This presentation from the Water Peer Review highlights one of the program's marine and hyrokinetics device design projects to scale up the current Ocean Power Technology PowerBuoy from 150kW to 500kW.

  7. 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.

  8. Wave Power Demonstration Project at Reedsport, Oregon

    SciTech Connect

    Mekhiche, Mike; Downie, Bruce

    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.

  9. 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.

  10. Energy and power modeling of multi mode lamb waves propagating in structure bonded with piezoelectric wafer active sensors

    NASA Astrophysics Data System (ADS)

    Kamal, Ayman; Lin, Bin; Giurgiutiu, Victor

    2013-01-01

    This paper presents a model for energy transfer between piezoelectric wafer active sensor (PWAS) and excited structures. Analytical models are developed for PWAS admittance, active power, Lamb waves kinetic, potential energies, and power. This model is based on Lamb waves; accordingly it is valid for high frequency multi-modal excitation analysis. Numerical simulation is done for (a) thin aluminum plate, where only first symmetric and antisymmetric exist, and (b) thick steel plate example is presented to show the case of multi-modal wave propagation. Parametric studies for different excitation frequencies and different transducer sizes are done to show the best match of (frequency/PWAS size) for exciting structures.

  11. Stability analysis of the Gyroscopic Power Take-Off wave energy point absorber

    NASA Astrophysics Data System (ADS)

    Nielsen, Søren R. K.; Zhang, Zili; Kramer, Morten M.; Olsen, Jan

    2015-10-01

    The Gyroscopic Power Take-Off (GyroPTO) wave energy point absorber consists of a float rigidly connected to a lever. The operational principle is somewhat similar to that of the so-called gyroscopic hand wrist exercisers, where the rotation of the float is brought forward by the rotational particle motion of the waves. At first, the equations of motion of the system are derived based on analytical rigid body dynamics. Next, assuming monochromatic waves simplified equations are derived, valid under synchronisation of the ring of the gyro to the angular frequency of the excitation. Especially, it is demonstrated that the dynamics of the ring can be described as an autonomous nonlinear single-degree-of-freedom system, affected by three different types of point attractors. One where the ring vibrations are attracted to a static equilibrium point indicating unstable synchronisation and two types of attractors where the ring is synchronised to the wave angular frequency, either rotating in one or the opposite direction. Finally, the stability conditions and the basins of attraction to the point attractors defining the synchronised motion are determined.

  12. PTO-Sim: Development of a Power Take Off Modeling Tool for Ocean Wave Energy Conversion

    E-print Network

    goal of developing WEC-Sim is to promote and support the wave energy industry. Since WEC-Sim is an open and has been adopted by many wave energy developers in the WEC industry due to its relatively simple plate. The float is connected Fig. 1. RM3 model in WEC-Sim (left) and with the animation (right) [1

  13. 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.

  14. DEVELOPMENT OF PTO-SIM: A POWER PERFORMANCE MODULE FOR THE OPEN-SOURCE WAVE ENERGY CONVERTER CODE WEC-SIM

    E-print Network

    DEVELOPMENT OF PTO-SIM: A POWER PERFORMANCE MODULE FOR THE OPEN-SOURCE WAVE ENERGY CONVERTER CODE WEC-SIM Ratanak So Asher Simmons Ted Brekken School of Electrical Engineering and Computer Science National Laboratories Albuquerque, NM USA Email: kelley.ruehl@sandia.gov ABSTRACT WEC-Sim (Wave Energy

  15. 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.

  16. 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

  17. 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 ...

  18. The Effects of Wave Energy Converters on a Monochromatic Wave Climate

    E-print Network

    Fox-Kemper, Baylor

    is that of wave energy. The research is multifaceted and includes research on the efficiency of wave energy and mean wave period of wave energy fields. There is tremendous energy potential in the ocean. Solar energy is much higher than that of solar power, with energy densities reaching 60kW hr/m2 . In addition to higher

  19. 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.

  20. The use of exact Lamb waves modes for modeling the power and energy transduction of structurally bonded piezoelectric wafer active sensors

    NASA Astrophysics Data System (ADS)

    Lin, Bin; Giurgiutiu, Victor; Kamal, Ayman M.

    2012-04-01

    This paper presents a theoretical modeling of power and energy transduction of structurally-bonded piezoelectric wafer active sensors (PWAS) for structural health monitoring (SHM). After a literature review of the state of the art, we developed a model of power and energy transduction between the PWAS and a structure containing multimodal ultrasonic guided waves. The use of exact Lamb waves modes for power modeling is an extension of our previously presented simplified model that considered axial and flexural waves with low frequency approximation. The model assumptions include: (a) straight-crested multimodal ultrasonic guided wave propagation; (b) ideal bonding (pin-force) connection between PWAS and structure; (c) ideal excitation source at the transmitter PWAS and fully-resistive external load at the receiver PWAS. Frequency response functions are developed for voltage, current, complex power, active power, etc. Multimodal ultrasonic guided wave, normal mode expansion, electromechanical energy transformation of PWAS and structure were considered. The parametric study of PWAS size and impedance match gives the PWAS design guideline for PWAS sensing and power harvesting applications

  1. Wireless power transmission using ultrasonic guided waves

    NASA Astrophysics Data System (ADS)

    Kural, A.; Pullin, R.; Featherston, C.; Paget, C.; Holford, K.

    2011-07-01

    The unavailability of suitable power supply at desired locations is currently an important obstacle in the development of distributed, wireless sensor networks for applications such as structural health monitoring of aircraft. Proposed solutions range from improved batteries to energy harvesting from vibration, temperature gradients and other sources. A novel approach is being investigated at Cardiff University School of Engineering in cooperation with Airbus. It aims to utilise ultrasonic guided Lamb waves to transmit energy through the aircraft skin. A vibration generator is to be placed in a location where electricity supply is readily available. Ultrasonic waves generated by this device will travel through the aircraft structure to a receiver in a remote wireless sensor node. The receiver will convert the mechanical vibration of the ultrasonic waves back to electricity, which will be used to power the sensor node. This paper describes the measurement and modelling of the interference pattern which emerges when Lamb waves are transmitted continuously as in this power transmission application. The discovered features of the pattern, such as a large signal amplitude variation and a relatively high frequency, are presented and their importance for the development of a power transmission system is discussed.

  2. Controller for a wave energy converter

    DOEpatents

    Wilson, David G.; Bull, Diana L.; Robinett, III, Rush D.

    2015-09-22

    A wave energy converter (WEC) is described, the WEC including a power take off (PTO) that converts relative motion of bodies of the WEC into electrical energy. A controller controls operation of the PTO, causing the PTO to act as a motor to widen a wave frequency spectrum that is usable to generate electrical energy.

  3. Overview of Ocean Wave and Tidal Energy Lingchuan Mei

    E-print Network

    Lavaei, Javad

    and consistency can ensure us ocean a dependable source of power that we can rely on. However, wave and tidal. keywords--Renewable power resource, Marine energy, wave energy, tidal energy. I. INTRODUCTION For recentOverview of Ocean Wave and Tidal Energy Lingchuan Mei Department of Electrical Engineering Columbia

  4. WAVE ENERGY RESOURCE CHARACTERIZATION US NAVY WAVE ENERGY TEST SITE

    E-print Network

    WAVE ENERGY RESOURCE CHARACTERIZATION AT THE US NAVY WAVE ENERGY TEST SITE AND OTHER LOCATIONS Department of Energy under Award Number DE-FG36-08GO18180 November 1, 2014 #12;ii Summary Numerical wave hindcasting from surface winds provides an important source of information for wave energy resource assessment

  5. 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%.

  6. ALPHA POWER CHANNELLING WITH TWO WAVES N.J. FISCH, M.C. HERRMANN

    E-print Network

    not to extract most of the recoverable energy [5-71. A poloidally and toroidally propagating lower hybrid waveALPHA POWER CHANNELLING WITH TWO WAVES N.J. FISCH, M.C. HERRMANN Princeton Plasma Physics of waves, rather than by one wave alone. While one wave constrains more firmly the direction of the energy

  7. Structured shock waves and the fourth-power law

    NASA Astrophysics Data System (ADS)

    Grady, Dennis E.

    2010-01-01

    A fourth-power law relating the stress jump through a steady structured shock wave and the maximum strain rate within the shock wave has received recognition as a unifying relation over a sensibly wide range of materials and shock compression amplitudes. Less widely recognized is the complementary applicability of the invariance of the product of the energy dissipated and the time over which this energy is dissipated through a structure shock wave—a property with the dimensions of action. While the latter invariance implies the fourth-power behavior for steady shock waves, this invariance also has an apparent application to unsteady structured waves under certain conditions. A brief history of the origin of the fourth-power law is provided. Some commentary is offered on the physical principles of solid viscosity in the shock wave and the underlying invariance of the energy-time product in the shock wave event. The results for steady structured waves in porous and composite solids, which do not in general exhibit fourth-power behavior, are examined. Observations of systematic behaviors with component cell size and impedance disparities suggest acoustic scattering may contribute to wave structuring in selected materials.

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

    E-print Network

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

    2014-01-01

    In order to predict the response of wave energy converters an accurate representation of the wave climate resource is crucial. This paper gives an overview of wave resource modeling techniques as well as detailing a methodology for estimating...

  9. Key features of wave energy.

    PubMed

    Rainey, R C T

    2012-01-28

    For a weak point source or dipole, or a small body operating as either, we show that the power from a wave energy converter (WEC) is the product of the particle velocity in the waves, and the wave force (suitably defined). There is a thus a strong analogy with a wind or tidal turbine, where the power is the product of the fluid velocity through the turbine, and the force on it. As a first approximation, the cost of a structure is controlled by the force it has to carry, which governs its strength, and the distance it has to be carried, which governs its size. Thus, WECs are at a disadvantage compared with wind and tidal turbines because the fluid velocities are lower, and hence the forces are higher. On the other hand, the distances involved are lower. As with turbines, the implication is also that a WEC must make the most of its force-carrying ability-ideally, to carry its maximum force all the time, the '100% sweating WEC'. It must be able to limit the wave force on it in larger waves, ultimately becoming near-transparent to them in the survival condition-just like a turbine in extreme conditions, which can stop and feather its blades. A turbine of any force rating can achieve its maximum force in low wind speeds, if its diameter is sufficiently large. This is not possible with a simple monopole or dipole WEC, however, because of the 'n?/2?' capture width limits. To achieve reasonable 'sweating' in typical wave climates, the force is limited to about 1?MN for a monopole device, or 2?MN for a dipole. The conclusion is that the future of wave energy is in devices that are not simple monopoles or dipoles, but multi-body devices or other shapes equivalent to arrays. PMID:22184669

  10. Modeling, Control, and Simulation of Battery Storage Photovoltaic-Wave Energy Hybrid Renewable Power Generation Systems for Island Electrification in Malaysia

    PubMed Central

    Samrat, Nahidul Hoque; Ahmad, Norhafizan Bin; Choudhury, Imtiaz Ahmed; Taha, Zahari Bin

    2014-01-01

    Today, the whole world faces a great challenge to overcome the environmental problems related to global energy production. Most of the islands throughout the world depend on fossil fuel importation with respect to energy production. Recent development and research on green energy sources can assure sustainable power supply for the islands. But unpredictable nature and high dependency on weather conditions are the main limitations of renewable energy sources. To overcome this drawback, different renewable sources and converters need to be integrated with each other. This paper proposes a standalone hybrid photovoltaic- (PV-) wave energy conversion system with energy storage. In the proposed hybrid system, control of the bidirectional buck-boost DC-DC converter (BBDC) is used to maintain the constant dc-link voltage. It also accumulates the excess hybrid power in the battery bank and supplies this power to the system load during the shortage of hybrid power. A three-phase complex vector control scheme voltage source inverter (VSI) is used to control the load side voltage in terms of the frequency and voltage amplitude. Based on the simulation results obtained from Matlab/Simulink, it has been found that the overall hybrid framework is capable of working under the variable weather and load conditions. PMID:24892049

  11. Modeling, control, and simulation of battery storage photovoltaic-wave energy hybrid renewable power generation systems for island electrification in Malaysia.

    PubMed

    Samrat, Nahidul Hoque; Bin Ahmad, Norhafizan; Choudhury, Imtiaz Ahmed; Bin Taha, Zahari

    2014-01-01

    Today, the whole world faces a great challenge to overcome the environmental problems related to global energy production. Most of the islands throughout the world depend on fossil fuel importation with respect to energy production. Recent development and research on green energy sources can assure sustainable power supply for the islands. But unpredictable nature and high dependency on weather conditions are the main limitations of renewable energy sources. To overcome this drawback, different renewable sources and converters need to be integrated with each other. This paper proposes a standalone hybrid photovoltaic- (PV-) wave energy conversion system with energy storage. In the proposed hybrid system, control of the bidirectional buck-boost DC-DC converter (BBDC) is used to maintain the constant dc-link voltage. It also accumulates the excess hybrid power in the battery bank and supplies this power to the system load during the shortage of hybrid power. A three-phase complex vector control scheme voltage source inverter (VSI) is used to control the load side voltage in terms of the frequency and voltage amplitude. Based on the simulation results obtained from Matlab/Simulink, it has been found that the overall hybrid framework is capable of working under the variable weather and load conditions. PMID:24892049

  12. 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.

  13. Tunable multi-channel terahertz wave power splitter

    NASA Astrophysics Data System (ADS)

    Jiu-Sheng, Li; Han, Liu; Le, Zhang

    2015-12-01

    The combination of terahertz technology and photonic crystal provides a new approach to realize compact terahertz wave devices. Relying on a conventional photonic crystal waveguide and photonic crystal surface-mode waveguides, a tunable multi-channel terahertz-wave power splitter is proposed. The mechanism of such a power splitter is further theoretically analyzed and numerically investigated with the aid of the plane-wave-expansion method and the finite-difference time-domain method. With an appropriate design, the proposed device can split the input terahertz wave energy equally into six output ports at the frequency of 0.6 THz. When changing the external magnetic field, the input terahertz wave can be equally divided into four output ports with the aid of a magnetic-sensitive material. Furthermore, the present device is very compact and the total size is of 4.4×6.0 mm2.

  14. TerraPower's Traveling Wave Reactor

    NASA Astrophysics Data System (ADS)

    Ellis, Tyler

    2011-11-01

    TerraPower is moving forward with detailed plans for a sustainable, economic, and safe nuclear reactor. The Traveling Wave Reactor (TWR) -- a reactor in the 500-megawatt electric range - uses unique core physics to initiate a breed and burn wave which can be completely sustained in fertile material. This process allows the TWR to convert depleted uranium waste into usable fuel as the reactor operates, providing a sustainable base-load power source. TerraPower is the first company to create a practical engineering embodiment of this previously studied concept thanks to a powerful advanced reactor modeling interface, developed in-house, which enables the analysis of traveling wave reactor technology in a way that has not been possible before. This presentation will provide more detail about the origins of the TWR, the project's current status as well as some of the safety differences between TWRs and currently operating light water reactors.

  15. 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...

  16. An experimental study on a trapezoidal pendulum wave energy converter in regular waves

    NASA Astrophysics Data System (ADS)

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

    2015-06-01

    Experimental studies were conducted on a trapezoidal pendulum wave energy converter in regular waves. To obtain the incident wave height, the analytical method (AM) was used to separate the incident and reflected waves propagating in a wave flume by analysing wave records measured at two locations. The response amplitude operator (RAO), primary conversion efficiency and the total conversion efficiency of the wave energy converter were studied; furthermore, the power take-off damping coefficients corresponding to the load resistances in the experiment were also obtained. The findings demonstrate that the natural period for a pendulum wave energy converter is relatively large. A lower load resistance gives rise to a larger damping coefficient. The model shows relatively higher wave energy conversion efficiency in the range of 1.0-1.2 s for the incident wave period. The maximum primary conversion efficiency achieved was 55.5%, and the maximum overall conversion efficiency was 39.4%.

  17. Alpha Power Channeling with Two Waves N. J. Fisch and M. C. Herrmann

    E-print Network

    of the recoverable energy [5­7]. A poloidally and toroidally propagating lower hybrid wave was proposed [1] to makeAlpha Power Channeling with Two Waves N. J. Fisch and M. C. Herrmann Princeton Plasma Physics is likely to be realized only through the excitation of a variety of waves, rather than by one wave alone

  18. Alpha Power Channeling with Two Waves N. J. Fisch and M. C. Herrmann

    E-print Network

    not to extract most of the recoverable energy [5--7]. A poloidally and toroidally propagating lower hybrid waveAlpha Power Channeling with Two Waves N. J. Fisch and M. C. Herrmann Princeton Plasma Physics is likely to be realized only through the excitation of a variety of waves, rather than by one wave alone

  19. 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.

  20. Starting to Experiment with Wave Power

    ERIC Educational Resources Information Center

    Hare, Jonathan; McCallie, Ellen

    2005-01-01

    Outlined is a simple design for a working wave-powered electrical generator based on one made on the BBC "Rough Science" TV series. The design has been kept deliberately simple to facilitate rapid pupil/student involvement and most importantly so that there is much scope for their own ingenuity and ideas. The generator works on the principle of…

  1. Sunspot waves and flare energy release

    NASA Astrophysics Data System (ADS)

    Sych, R.; Karlický, M.; Altyntsev, A.; Dudík, J.; Kashapova, L.

    2015-05-01

    Context. We study the possibility of flare process triggering by waves propagating from the sunspot along a magnetic loop (channel) to a nearby flare site. Aims: We present a relationship between the dynamics of ~3-min slow magnetoacoustic waves in the sunspot and flare emergence process. Waves propagating in the magnetic channel whose one foot is anchored in the umbra represent the disturbing agent responsible for triggering the flare energy release. Methods: We applied time-distance plots and pixel wavelet filtration methods to obtain spatio-temporal distribution of wave power variations in radio and SDO/AIA data. To find the magnetic channel, we used potential magnetic field extrapolation of SDO/HMI magnetograms. The propagation velocity of wave fronts was measured from wave locations at specific times. Results: In the correlation curves of the 17 GHz (NoRH) radio emission, we found a monotonous energy amplification of the 3-min waves in the sunspot umbra before the 2012 June 7 flare. This amplification was associated with an increase in the length of the oscillatory wakes in coronal loops (SDO/AIA, 171 Å) prior to the flare onset. A peculiarity of the flare is the constant level of the flare emission in soft X-rays (RHESSI, 3-25 keV) for ~10 min after the short impulsive phase, which indicates continuing energy release. Throughout this time, we found transverse oscillations of the flare loop with a 30 s period in the radio-frequency range (NoRH, 17 GHz). This period appears to be related to the 3-min waves from the sunspot. The magnetic field extrapolation based on SDO/HMI magnetograms shows the existence of the magnetic channel (waveguide) connecting the sunspot with the energy release region. Conclusions: We analysed the sunspot 3-min wave dynamics and found a correlation between the oscillation power amplification and flare triggering in the region connected to the sunspot through the magnetic channel. We propose that this amplified wave flux triggered the flare. The flare occurred because of this amplified flux, however, and because a sufficient amount of free magnetic energy was accumulated in close vicinity to the magnetic channel prior to the flare. Furthermore, because of loop heating, the wave velocity (sound velocity) increased with the penetration of waves into the energy release site. The heating is shown to be able to proceed after the flare main peak owing to a further energy pumping in the form of waves from the sunspot and additional reconnection episodes in the flare region.

  2. Ocean, Wave and Tidal Energy Systems; (USA)

    SciTech Connect

    Raridon, M.H.; Hicks, S.C.

    1991-01-01

    Ocean, Wave, and Tidal Energy Systems (OES) announces on a biomonthly basis the current worldwide information available on all aspects of ocean thermal energy conversion systems based on exploitation of the temperature difference between the surface water and ocean depth. All aspects of salinity gradient power systems based on extracting energy from mixing fresh water with seawater are included, along with information on wave and tidal power. This publication contains the abstracts of DOE reports, journal articles, conference papers, patents, theses, and monographs added to the Energy Science and Technology Database (EDB) during the past two months. Also included are US information obtained through acquisition programs or interagency agreements and international information obtained through the International Energy Agency's Energy Technology Data Exchange or government-to-government agreements.

  3. 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.

  4. Wave energy and intertidal productivity

    PubMed Central

    Leigh, Egbert G.; Paine, Robert T.; Quinn, James F.; Suchanek, Thomas H.

    1987-01-01

    In the northeastern Pacific, intertidal zones of the most wave-beaten shores receive more energy from breaking waves than from the sun. Despite severe mortality from winter storms, communities at some wave-beaten sites produce an extraordinary quantity of dry matter per unit area of shore per year. At wave-beaten sites of Tatoosh Island, WA, sea palms, Postelsia palmaeformis, can produce > 10 kg of dry matter, or 1.5 × 108 J, per m2 in a good year. Extraordinarily productive organisms such as Postelsia are restricted to wave-beaten sites. Intertidal organisms cannot transform wave energy into chemical energy, as photosynthetic plants transform solar energy, nor can intertidal organisms “harness” wave energy. Nonetheless, wave energy enhances the productivity of intertidal organisms. On exposed shores, waves increase the capacity of resident algae to acquire nutrients and use sunlight, augment the competitive ability of productive organisms, and protect intertidal residents by knocking away their enemies or preventing them from feeding. PMID:16593813

  5. Decadal wave power variability in the North-East Atlantic and North Sea

    NASA Astrophysics Data System (ADS)

    Santo, H.; Taylor, P. H.; Woollings, T.; Poulson, S.

    2015-06-01

    Estimation of the long-term behavior of wave climate is crucial for harnessing wave energy in a cost-effective way. Previous studies have linked wave heights to the north-south atmospheric pressure anomalies in the North Atlantic, suggesting that the wave climate fluctuates as a response to changes in zonal circulation in the atmosphere. We identify changes in wave power in the North-East Atlantic that are strongly correlated to the dominant pressure anomalies, the North Atlantic Oscillation (NAO), and other modes. We present a reconstructed wave power climate for 1665-2005, using a combination of known and proxy indices for the NAO and other modes. Our reconstruction shows high interannual and multidecadal variability, which makes wave energy prediction challenging. This variability should be considered in any long-term reliability analysis for wave energy devices and in power scheme economics.

  6. Guidelines in Wave Energy Conversion System Design 

    E-print Network

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

    2014-01-01

    mentions that the Pelamis is able to work in sea states with a power of at least 15 kilowatts per meter. Wave Dragon Wave Dragon is an overtopping device, which was developed in Denmark and Wales, and it was also reviewed by the EPRI in 2004... be done at the device site location. The Wave Dragon uses large wings (reflectors) to drive water into the reservoir. When water flows through the reservoir, it turns low head turbines to generate energy. The device takes advantage of its height...

  7. High power millimeter wave ECRH source needs for fusion program

    SciTech Connect

    Not Available

    1984-06-01

    This document stems from the four-day Gyrotron Symposium held at the US Department of Energy (DOE) Headquarters on June 13-16, 1983, and serves as a position paper for the Office of Fusion Energy, DOE, on high-power millimeter wave source development for Electron Cyclotron Heating (ECH) of plasmas. It describes the fusion program needs for gyrotron as ECH sources, their current status, and desirable development strategies.

  8. 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.

  9. Alpha power channeling using ion-Bernstein waves* N. J. Fischtna)

    E-print Network

    by plasma waves and then channeled to heat fuel ions. In principle, both increased reactivity and current-particle energy flows to the wave, rather than to collisional heating of the plasma. In practice, once an aAlpha power channeling using ion-Bernstein waves* N. J. Fischtna) Princeton Plasma Physics

  10. 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.

  11. 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.

  12. Direct Drive Wave Energy Buoy

    SciTech Connect

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

    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.

  13. 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 ...

  14. Wave Energy Development Roadmap: Design to Commercialization

    E-print Network

    Siefert, Chris

    .INTRODUCTION Wave energy is a renewable energy source with high energy density and great potential. Along the TRL guidelines and will then develop a roadmap describing the advancement of wave energy technologiesWave Energy Development Roadmap: Design to Commercialization Kelley Ruehl and Diana Bull Water

  15. Turning Renewable Energy Ambitions into Successful Projects: A Study of How Communication can be Improved in the Wave Power Sector. 

    E-print Network

    Lancaster, Gregor

    2011-11-24

    The purpose of the dissertation was to research how to improve communication between marine renewable energy developers and the stakeholders involved in their development. The process was qualitative and involved analysing ...

  16. Energy flow, energy density of Timoshenko beam and wave mode incoherence

    NASA Astrophysics Data System (ADS)

    Zhou, Jun; Rao, Zhushi; Ta, Na

    2015-10-01

    Time-averaged energy flow and energy density are of significance in vibration analysis. The wave decomposition method is more fruitful and global in physical sense than the state variables depicted point by point. By wave approach, the Timoshenko beam vibration field is decomposed into two distinct modes: travelling and evanescent waves. Consequently, the power and energy functions defined on these waves' amplitude and phase need to be established. However, such formulas on Timoshenko beam are hardly found in literatures. Furthermore, the incoherence between these two modes is of theoretical and practical significance. This characteristic guarantees that the resultant power or energy of a superposed wave field is equal to the sum of the power or energy that each wave mode would generate individually. Unlike Euler-Bernoulli beam, such incoherence in the Timoshenko beam case has not been theoretically proved so far. Initially, the power and energy formulas based on wave approach and the corresponding incoherence proof are achieved by present work, both in theoretical and numerical ways. Fortunately, the theoretical and numerical results show that the travelling and evanescent wave modes are incoherent with each other both on power and energy functions. Notably, the energy function is unconventional and self-defined in order to obtain the incoherence. Some remarkable power transmission characteristics of the evanescent wave are also illustrated meanwhile.

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

    NASA Astrophysics Data System (ADS)

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

    2015-05-01

    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.

  18. 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.

  19. On Using Cyclotron Waves for Output of Radiation from High-Power Relativistic Backward-Wave Oscillators

    NASA Astrophysics Data System (ADS)

    Goykhman, M. B.; Gromov, A. V.; Kladukhin, V. V.; Kovalev, N. F.; Kolganov, N. G.; Palitsin, A. V.

    2014-09-01

    We discuss the scheme of a high-power relativistic backward-wave oscillator operating with a high-current explosive-emission electron beam. The radiation output from the tube is based on reflection of the operating wave into a fast cyclotron wave which transmits the energy of the high-frequency field towards the collector. At the collector, reverse conversion into the output electromagnetic wave takes place. The proposed scheme allows one to increase electric strength, as well as the transverse size of the working space of the backward-wave oscillator. It is shown that within the proposed scheme, one can reduce the focusing magnetic field without decreasing the power of the output radiation.

  20. 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 ...

  1. 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.

  2. Wave energy propelling marine ship

    SciTech Connect

    Kitabayashi, S.

    1982-06-29

    A wave energy propelling marine ship comprises a cylindrical ship body having a hollow space therein for transporting fluid material therewithin, a ship body disposed in or on the sea; a propeller attached to the ship body for the purpose of propelling the marine ship for sailing; a rudder for controlling the moving direction of the marine ship; at least one rotary device which includes a plurality of compartments which are each partitioned into a plurality of water chambers by a plurality of radial plates, and a plurality of water charge and/or discharge ports, wherein wave energy is converted into mechanical energy; and device for adjusting buoyancy of the marine ship so that the rotary device is positioned advantageously on the sea surface.

  3. Accuracy of Satellite-Measured Wave Heights in the Australian Region for Wave Power Applications

    ERIC Educational Resources Information Center

    Meath, Sian E.; Aye, Lu; Haritos, Nicholas

    2008-01-01

    This article focuses on the accuracy of satellite data, which may then be used in wave power applications. The satellite data are compared to data from wave buoys, which are currently considered to be the most accurate of the devices available for measuring wave characteristics. This article presents an analysis of satellite- (Topex/Poseidon) and…

  4. Energy harvesting from sea waves with consideration of airy and JONSWAP theory and optimization of energy harvester parameters

    NASA Astrophysics Data System (ADS)

    Mirab, Hadi; Fathi, Reza; Jahangiri, Vahid; Ettefagh, Mir Mohammad; Hassannejad, Reza

    2015-12-01

    One of the new methods for powering low-power electronic devices at sea is a wave energy harvesting system. In this method, piezoelectric material is employed to convert the mechanical energy of sea waves into electrical energy. The advantage of this method is based on avoiding a battery charging system. Studies have been done on energy harvesting from sea waves, however, considering energy harvesting with random JONSWAP wave theory, then determining the optimum values of energy harvested is new. This paper does that by implementing the JONSWAP wave model, calculating produced power, and realistically showing that output power is decreased in comparison with the more simple airy wave model. In addition, parameters of the energy harvester system are optimized using a simulated annealing algorithm, yielding increased produced power.

  5. Directional wave climate and power variability along the Southeast Australian shelf

    NASA Astrophysics Data System (ADS)

    Mortlock, Thomas R.; Goodwin, Ian D.

    2015-04-01

    Variability in the modal wave climate is a key process driving large-scale coastal behaviour on moderate- to high-energy sandy coastlines, and is strongly related to variability in synoptic climate drivers. On sub-tropical coasts, shifts in the sub-tropical ridge (STR) modulate the seasonal occurrence of different wave types. However, in semi-enclosed seas, isolating directional wave climates and synoptic drivers is hindered by a complex mixed sea-swell environment. Here we present a directional wave climate typology for the Tasman Sea based on a combined statistical-synoptic approach using mid-shelf wave buoy observations along the Southeast Australian Shelf (SEAS). Five synoptic-scale wave climates exist during winter, and six during summer. These can be clustered into easterly (Tradewind), south-easterly (Tasman Sea) and southerly (Southern Ocean) wave types, each with distinct wave power signatures. We show that a southerly shift in the STR and trade-wind zone, consistent with an observed poleward expansion of the tropics, forces an increase in the total wave energy flux in winter for the central New South Wales shelf of 1.9 GJ m-1 wave-crest-length for 1° southerly shift in the STR, and a reduction of similar magnitude (approximately 1.8 GJ m-1) during summer. In both seasons there is an anti-clockwise rotation of wave power towards the east and south-east at the expense of southerly waves. Reduced obliquity of constructive wave power would promote a general disruption to northward alongshore sediment transport, with the cross-shore component becoming increasingly prevalent. Results are of global relevance to sub-tropical east coasts where the modal wave climate is influenced by the position of the zonal STR.

  6. Efficiency analysis of a pneu-mechanical Wave Energy Converter : model of the device losses,

    E-print Network

    Psaltis, Demetri

    ENAC/ Efficiency analysis of a pneu-mechanical Wave Energy Converter : model of the device losses. Van Herle 1 Mots Clés: Efficiency Analysis, Power Take Off, Renewable Energy, WEC, Wave Energy. 1 CONTEXTGOALSRESULTSCONCLUSION Method flowchart · CorPower Ocean AB aims at provide a high-efficiency and cost-effective PTO unit

  7. ULF wave power features in the topside ionosphere revealed by Swarm observations

    NASA Astrophysics Data System (ADS)

    Balasis, Georgios; Papadimitriou, Constantinos; Daglis, Ioannis A.; Pilipenko, Viacheslav

    2015-09-01

    Recently developed automated methods for deriving the characteristics of ultra low frequency (ULF) waves are applied to the Swarm data sets in order to retrieve new information about the near-Earth electromagnetic environment. Here we present the first ULF wave observations by Swarm, analyzing 1 year data from the mission. We find evidence for the decay of the amplitude of the Pc3 (20-100 mHz) signal with altitude in the topside ionosphere as predicted by theoretical models of wave propagation. We show that the major characteristics of the Swarm ULF power maps generally agree with respect to the wave activity seen by the upper satellite and the lower pair of satellites when the power spectrum of the upper satellite is shifted by 1 h in magnetic local time. Moreover, a puzzling enhancement, not predicted by current ULF wave theories, of compressional Pc3 wave energy was revealed by Swarm in the region of South Atlantic Anomaly.

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

    SciTech Connect

    Mirko Previsic

    2010-06-17

    Given proper care in siting, design, deployment, operation and maintenance, wave energy conversion could become one of the more environmentally benign sources of electricity generation. In order to accelerate the adoption of these emerging hydrokinetic and marine energy technologies, navigational and environmental concerns must be identified and addressed. All developing hydrokinetic projects involve a wide variety of stakeholders. One of the key issues that site developers face as they engage with this range of stakeholders is that, due to a lack of technical certainty, many of the possible conflicts (e.g., shipping and fishing) and environmental issues are not well-understood,. In September 2008, re vision consulting, LLC was selected by the Department of Energy (DoE) to apply a scenario-based assessment to the emerging hydrokinetic technology sector in order to evaluate the potential impact of these technologies on the marine environment and navigation constraints. The project’s scope of work includes the establishment of baseline scenarios for wave and tidal power conversion at potential future deployment sites. The scenarios capture variations in technical approaches and deployment scales to properly identify and characterize environmental effects and navigational effects. The goal of the project is to provide all stakeholders with an improved understanding of the potential range of technical attributes and potential effects of these emerging technologies and focus all stakeholders on the critical issues that need to be addressed. By identifying and addressing navigational and environmental concerns in the early stages of the industry’s development, serious mistakes that could potentially derail industry-wide development can be avoided. This groundwork will also help in streamlining siting and associated permitting processes, which are considered key hurdles for the industry’s development in the U.S. today. Re vision is coordinating its efforts with two other project teams funded by DoE which are focused on regulatory issues (Pacific Energy Ventures) and navigational issues (PCCI). The results of this study are structured into three reports: (1) Wave power scenario description (2) Tidal power scenario description (3) Framework for Identifying Key Environmental Concerns This is the first report in the sequence and describes the results of conceptual feasibility studies of wave power plants deployed in Humboldt County, California and Oahu, Hawaii. These two sites contain many of the same competing stakeholder interactions identified at other wave power sites in the U.S. and serve as representative case studies. Wave power remains at an early stage of development. As such, a wide range of different technologies are being pursued by different manufacturers. In order to properly characterize potential effects, it is useful to characterize the range of technologies that could be deployed at the site of interest. An industry survey informed the process of selecting representative wave power devices. The selection criteria requires that devices are at an advanced stage of development to reduce technical uncertainties, and that enough data are available from the manufacturers to inform the conceptual design process of this study. Further, an attempt is made to cover the range of different technologies under development to capture variations in potential environmental effects. Table 1 summarizes the selected wave power technologies. A number of other developers are also at an advanced stage of development, but are not directly mentioned here. Many environmental effects will largely scale with the size of the wave power plant. In many cases, the effects of a single device may not be measurable, while larger scale device arrays may have cumulative impacts that differ significantly from smaller scale deployments. In order to characterize these effects, scenarios are established at three deployment scales which nominally represent (1) a small pilot deployment, (2) a small commercial deployment, and (3) a large commercial sc

  9. 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.

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

    E-print Network

    Wirosoetisno, Djoko

    Using a Bore-Soliton-Splash to understand Rogue Waves, Tsunamis & Wave Energy Onno Bokhove, Elena it. · Explore: relation w. tsunamis, wave pumps & wave energy? 2 Set-up Water Wave Channel · Two vorticity [2]. · Optimize abnormality index for BSS. 6 Rogue Waves and Tsunamis · Nonlinear rogue waves

  11. Note on Salter's energy absorber in random waves

    SciTech Connect

    Serman, D.D.; Mei, C.C.

    1980-01-01

    Salter's wave theory energy device has been the object of extensive theoretical and experimental studies during recent years. This paper describes the performance of the device in random waves by means of a numerical study. Different situations are considered. First, the cam is allowed to have one degree of freedom (the cam rolls about a rigid and fixed shaft) and is in a shallow sea where the waves are modeled by the JONSWAP spectrum. Power extraction, efficiency and dynamic response are presented in terms of wind characteristics for a cam radius of 3 m. In the open sea where typical waves are longer and higher, waves are represented by the P-M spectrum and the cam radius is taken to be 7 m. Finally, it is shown for a particular set of design parameters how the efficiency decays and the power extraction decreases with lack of rigidity in the support system.

  12. Ocean floor mounting of wave energy converters

    DOEpatents

    Siegel, Stefan G

    2015-01-20

    A system for mounting a set of wave energy converters in the ocean includes a pole attached to a floor of an ocean and a slider mounted on the pole in a manner that permits the slider to move vertically along the pole and rotate about the pole. The wave energy converters can then be mounted on the slider to allow adjustment of the depth and orientation of the wave energy converters.

  13. Modeling explosion generated Scholte waves in sandy sediments with power law dependent shear wave speed.

    PubMed

    Soloway, Alexander G; Dahl, Peter H; Odom, Robert I

    2015-10-01

    Experimental measurements of Scholte waves from underwater explosions collected off the coast of Virginia Beach, VA in shallow water are presented. It is shown here that the dispersion of these explosion-generated Scholte waves traveling in the sandy seabed can be modeled using a power-law dependent shear wave speed profile and an empirical source model that determines the pressure time-series at 1?m from the source as a function of TNT-equivalent charge weight. PMID:26520346

  14. Powerful gravitational-wave bursts from supernova neutrino oscillations

    NASA Astrophysics Data System (ADS)

    Mosquera Cuesta, Herman J.; Fiuza, Karen

    2004-12-01

    During supernova core collapse and bounce resonant active-to-active, as well as active-to-sterile, neutrino (v) oscillations can take place. Over this phase weak magnetism increases antineutrino mean free paths, and thus its luminosity. Because oscillations feed mass-energy into the target v species, the large mass-squared difference between v states implies a huge amount of power to be given off as gravitational waves (GWs) due to the spin-rotation and spin-magnetic coupling driven v anisotropic flow, which is coherent over the oscillation length. The spacetime strain produced is about two orders of magnitude larger than those from v difussion or neutron star matter anisotropies. GWs observatories as LIGO, VIRGO, GEO-600, TAMA-300, etc., can search for these bursts far out to the VIRGO cluster of galaxies.

  15. On the Crest of a Wave: A Review of Wave Power Technology

    ERIC Educational Resources Information Center

    Harris, Fank

    2014-01-01

    The energy potentially available from waves around the coast of the UK far exceeds our domestic and industrial demands and yet, despite much research, numerous patent applications and several pilot schemes, the exploitation of waves for their energy largely remains in transition between development and commercialisation. This article examines the…

  16. Optimisation Of a Magnetostrictive Wave Energy Converter

    NASA Astrophysics Data System (ADS)

    Mundon, T. R.; Nair, B.

    2014-12-01

    Oscilla Power, Inc. (OPI) is developing a patented magnetostrictive wave energy converter aimed at reducing the cost of grid-scale electricity from ocean waves. Designed to operate cost-effectively across a wide range of wave conditions, this will be the first use of reverse magnetostriction for large-scale energy production. The device architecture is a straightforward two-body, point absorbing system that has been studied at length by various researchers. A large surface float is anchored to a submerged heave (reaction) plate by multiple taut tethers that are largely made up of discrete, robust power takeoff modules that house the magnetostrictive generators. The unique generators developed by OPI utilize the phenomenon of reverse magnetostriction, which through the application of load to a specific low cost alloy, can generate significant magnetic flux changes, and thus create power through electromagnetic induction. Unlike traditional generators, the mode of operation is low-displacement, high-force, high damping which in combination with the specific multi-tether configuration creates some unique effects and interesting optimization challenges. Using an empirical approach with a combination of numerical tools, such as ORCAFLEX, and physical models, we investigated the properties and sensitivities of this system arrangement, including various heave plate geometries, with the overall goal of identifying the mass and hydrodynamic parameters required for optimum performance. Furthermore, through a detailed physical model test program at the University of New Hampshire, we were able to study in more detail how the heave plate geometry affects the drag and added mass coefficients. In presenting this work we will discuss how alternate geometries could be used to optimize the hydrodynamic parameters of the heave plate, allowing maximum inertial forces in operational conditions, while simultaneously minimizing the forces generated in extreme waves. This presentation will cover the significant findings from this research, including physical model results and identified sensitivity parameters. In addition, we will discuss some preliminary results from our large-scale ocean trial conducted in August & September of this year.

  17. 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

  18. 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

  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. Ocean, Wave, and Tidal Energy Systems: Current abstracts

    NASA Astrophysics Data System (ADS)

    Smith, L.; Lane, D. W.

    1988-01-01

    Ocean, Wave, and Tidal Energy Systems (OES) announces on a bimonthly basis the current worldwide information available on all aspects of ocean thermal energy conversion systems based on exploitation of the temperature difference between the surface water and ocean depth. All aspects of salinity gradient power systems based on extracting energy from mixing fresh water with seawater are included, along with information on wave and tidal power. This publication contains the abstracts of DOE reports, journal articles, conference papers, patents, theses, and monographs added to the Energy Data Base (EDB) during the past two months. Also included are U.S. information obtained through acquisition programs or interagency agreements and international information obtained through the International Energy Agency's Energy Technology Data Exchange or government-to-government agreements.

  1. 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.

  2. 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.

  3. 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…

  4. Analysis of the power capacity of overmoded slow wave structures

    SciTech Connect

    Zhang, Dian; Zhang, Jun; Zhong, Huihuang; Jin, Zhenxing

    2013-07-15

    As the generated wavelength shortens, overmoded slow wave structures (SWSs) with large diameters are employed in O-type Cerenkov high power microwave (HPM) generators to achieve high power capacity. However, reported experimental results suggest that overmoded slow wave HPM generators working at millimeter wavelength output much lower power than those working at X-band do, despite the fact that the value of D/? (here, D is the average diameter of SWSs and ? is the generated wavelength) of the former is much larger than that of the latter. In order to understand this, the characteristics of the power capacity of the TM{sub 0n} modes in overmoded SWSs are numerically investigated. Our analysis reveals the following facts. First, the power capacity of higher order TM{sub 0n} modes is apparently larger than that of TM{sub 01} mode. This is quite different from the conclusion got in the foregone report, in which the power capacity of overmoded SWSs is estimated by that of smooth cylindrical waveguides. Second, the rate at which the power capacity of TM{sub 01} mode in overmoded SWSs grows with diameter does not slow down as the TM{sub 01} field transforms from “volume wave” to “surface wave.” Third, once the diameter of overmoded SWSs and the beam voltage are fixed, the power capacity of TM{sub 01} wave drops as periodic length L shortens and the generated frequency rises, although the value of D/? increases significantly. Therefore, it is necessary to investigate the capability of annular electron beam to interact efficiently with higher order TM{sub 0n} modes in overmoded SWSs if we want to improve the power capacity of overmoded O-type Cerenkov HPM generators working at high frequency.

  5. Simulation of coastal wave spectra energy from ENVISAT satellite data

    NASA Astrophysics Data System (ADS)

    Marghany, Maged

    2014-06-01

    In the last two decades, scientists have developed several powerful techniques to retrieve energy from natural sources such as a sun radiations, oceans and winds. This study is aimed at stimulating wave energy from large scale synthetic aperture radar (SAR) during different monsoon periods. In doing so, the nonlinear velocity bunching algorithm is used to retrieve the information of ocean wave spectra parameters such as significant wave height, directions, and energy on offshore, midshore, and onshore. Therefore, the maximum peak of the wave energy spectra density of 1.4 m2 s has occurred during northeast monsoon period. It is clear that the mid-shore and onshore has the highest peak of 0.8 and 1.37 m2 s, respectively as compared to offshore. In conclusions, a nonlinear algorithm of velocity bunching can be used to retrieve the significant wave height from synthetic aperture radar (SAR). In addition, SAR can be used to map the distribution of ocean wave spectra energy and determined the potential energy zone in Malaysia coastal waters.

  6. 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 ...

  7. 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

    energy in the GOM is explored and verified. Based on the findings, there is great potential in the GOM for wave energy technology and it is expected that the wave energy captured from the GOM can provide a considerable portion of power required by oil...

  8. 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

  9. A review of hydrodynamic investigations into arrays of ocean wave energy converters

    E-print Network

    De Chowdhury, S; Sanchez, A Madrigal; Fleming, A; Winship, B; Illesinghe, S; Toffoli, A; Babanin, A; Penesis, I; Manasseh, R

    2015-01-01

    Theoretical, numerical and experimental studies on arrays of ocean wave energy converter are reviewed. The importance of extracting wave power via an array as opposed to individual wave-power machines has long been established. There is ongoing interest in implementing key technologies at commercial scale owing to the recent acceleration in demand for renewable energy. To date, several reviews have been published on the science and technology of harnessing ocean-wave power. However, there have been few reviews of the extensive literature on ocean wave-power arrays. Research into the hydrodynamic modelling of ocean wave-power arrays is analysed. Where ever possible, comparisons are drawn with physical scaled experiments. Some critical knowledge gaps have been found. Specific emphasis has been paid on understanding how the modelling and scaled experiments are likely to be complementary to each other.

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

    SciTech Connect

    Makino, R. Kobayashi, K.; Kubo, S.; Kobayashi, S.; Shimozuma, T.; Yoshimura, Y.; Igami, H.; Takahashi, H.; Mutoh, T.

    2014-11-15

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

  11. 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.

  12. Master of Science Program in Power and Energy Systems

    E-print Network

    Haimovich, Alexander

    systems, renewable energy sources, solar-cells, fuel-cells and other advances in energy production. Exploiting renewable energy sources ­ sun, wind, geothermal, (wave,) hydraulic and others ­ presents a most Professional ECE 611 Transients in Power Systems Skills and ECE 618 Renewable Energy Systems Area Requirement

  13. 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?

  14. Energy Extraction from a Slider-Crank Wave Energy under Irregular Wave Conditions: Preprint

    SciTech Connect

    Sang, Yuanrui; Karayaka, H. Bora; Yan, Yanjun; Zhang, James Z.; Muljadi, Eduard; Yu, Yi-Hsiang

    2015-08-24

    A slider-crank wave energy converter (WEC) is a novel energy conversion device. It converts wave energy into electricity at a relatively high efficiency, and it features a simple structure. Past analysis on this particular WEC has been done under regular sinusoidal wave conditions, and suboptimal energy could be achieved. This paper presents the analysis of the system under irregular wave conditions; a time-domain hydrodynamics model is adopted and a rule-based control methodology is introduced to better serve the irregular wave conditions. Results from the simulations show that the performance of the system under irregular wave conditions is different from that under regular sinusoidal wave conditions, but a reasonable amount of energy can still be extracted.

  15. WEC-Sim (Wave Energy Converter - SIMulator)

    SciTech Connect

    2014-11-26

    WEC-Sim (Wave Energy Converter SIMulator) is a code developed by Sandia National Laboratories and the National Renewable Energy Laboratory to model wave energy converters (WECs) when they are subject to operational waves. The code is a time-domain modeling tool developed in MATLAB/Simulink using the multi-body dynamics solver SimMechanics. In WEC-Sim, WECs are modeled by connecting rigid bodies to one another with joint or constraint blocks from the WEC-Sim library. WEC-Sim is a publicly available, open-source code to model WECs.

  16. WEC-Sim (Wave Energy Converter - SIMulator)

    Energy Science and Technology Software Center (ESTSC)

    2014-11-26

    WEC-Sim (Wave Energy Converter SIMulator) is a code developed by Sandia National Laboratories and the National Renewable Energy Laboratory to model wave energy converters (WECs) when they are subject to operational waves. The code is a time-domain modeling tool developed in MATLAB/Simulink using the multi-body dynamics solver SimMechanics. In WEC-Sim, WECs are modeled by connecting rigid bodies to one another with joint or constraint blocks from the WEC-Sim library. WEC-Sim is a publicly available, open-sourcemore »code to model WECs.« less

  17. Wave energy harvesting by piezoelectric flexible plates

    NASA Astrophysics Data System (ADS)

    Shoele, Kourosh

    2013-11-01

    The ocean tidal currents and waves are very attractive sources of energy for extraction due to their vast availability and very low environmental impacts. Among different technologies, the harvesting of flow energy through the flapping of flexible plates has recently gained attentions. The sustained oscillation of a flexible plate is the result of a fluid-structure interaction occurrence, mainly from two different situations. In the first case, the oscillation is from the fluttering instability of the plate. In the second case, the unsteady flow is presented in the incoming flow either from the oscillatory sources such as surface waves. The mechanical energy is then converted to electricity using piezoelectric patches connected to the plate. In this paper, we discuss the novel approach to extract the wave energy using piezoelectric plates and discuss how parameters of the piezoelectric plate can be adjusted to increase the amount of energy that can be extracted from the current and free-surface waves.

  18. Superoscillations without Sidebands: Power-Efficient Sub-Diffraction Imaging with Propagating Waves

    PubMed Central

    Wong, Alex M. H.; Eleftheriades, George V.

    2015-01-01

    A superoscillation wave is a special superposition of propagating electromagnetic (EM) waves which varies with sub-diffraction resolution inside a fixed region. This special property allows superoscillation waves to carry sub-diffraction details of an object into the far-field, and makes it an attractive candidate technology for super-resolution devices. However, the Shannon limit seemingly requires that superoscillations must exist alongside high-energy sidebands, which can impede its widespread application. In this work we show that, contrary to prior understanding, one can selectively synthesize a portion of a superoscillation wave and thereby remove its high-energy region. Moreover, we show that by removing the high-energy region of a superoscillation wave-based imaging device, one can increase its power efficiency by two orders of magnitude. We describe the concept behind this development, elucidate conditions under which this phenomenon occurs, then report fullwave simulations which demonstrate the successful, power-efficient generation of sub-wavelength focal spots from propagating waves. PMID:25677306

  19. Self-similar relativistic blast waves with energy injection

    NASA Astrophysics Data System (ADS)

    van Eerten, Hendrik

    2014-08-01

    A sufficiently powerful astrophysical source with power-law luminosity in time will give rise to a self-similar relativistic blast wave with a reverse shock travelling into the ejecta and a forward shock moving into the surrounding medium. Once energy injection ceases and the last energy is delivered to the shock front, the blast wave will transit into another self-similar stage depending only on the total amount of energy injected. I describe the effect of limited duration energy injection into environments with density depending on radius as a power law, emphasizing optical/X-ray Gamma-ray Burst afterglows as applications. The blast wave during injection is treated analytically, the transition following last energy injection with one-dimensional simulations. Flux equations for synchrotron emission from the forward and reverse shock regions are provided. The reverse shock emission can easily dominate, especially with different magnetizations for both regions. Reverse shock emission is shown to support both the reported X-ray and optical correlations between afterglow plateau duration and end time flux, independently of the luminosity power-law slope. The model is demonstrated by application to bursts 120521A and 090515, and can accommodate their steep post-plateau light-curve slopes.

  20. Power supply switching for a mm-wave asymmetric multilevel outphasing power amplifier system

    E-print Network

    Spaulding, Jonathon David

    2010-01-01

    This thesis demonstrates power switches to be used in our new Asymmetric Multilevel Outphasing (AMO) transmitter architecture at mm-wave frequencies. The AMO topology breaks the linearity vs. efficiency design objective ...

  1. Investigation on the possibility of extracting wave energy from the Texas coast

    NASA Astrophysics Data System (ADS)

    Haces-Fernandez, Francisco

    Due to the great and growing demand of energy consumption in the Texas Coast area, the generation of electricity from ocean waves is considered very important. The combination of the wave energy with offshore wind power is explored as a way to increase power output, obtain synergies, maximize the utilization of assigned marine zones and reduce variability. Previously literature has assessed the wave energy generation, combined with wind in different geographic locations such as California, Ireland and the Azores Island. In this research project, the electric power generation from ocean waves on the Texas Coast was investigated, assessing its potential from the meteorological data provided by five buoys from National Data Buoy Center of the National Oceanic and Atmospheric Administration, considering the Pelamis 750 kW Wave Energy Converter (WEC) and the Vesta V90 3 MW Wind Turbine. The power output from wave energy was calculated for the year 2006 using Matlab, and the results in several locations were considered acceptable in terms of total power output, but with a high temporal variability. To reduce its variability, wave energy was combined with wind energy, obtaining a significant reduction on the coefficient of variation on the power output. A Matlab based interface was created to calculate power output and its variability considering data from longer periods of time.

  2. 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.

  3. Wave energy conversion systems:optimal localization offshore Italian coastlines

    NASA Astrophysics Data System (ADS)

    Benassai, Guido; Morucci, Sara

    2010-05-01

    A method for evaluating renewable energy technologies in terms of costs and engineering solutions has been implemented on the Italian coastlines, in order to achieve the optimal localization and choose the best wave energy conversion technology avoiding the transfer of systems suitable for more energetic seas. The Italian coastal wave climate was studied in detail. The study used four years of wave data from 14 sites offshore the Italian coastlines, of which six offshore the coastlines of Sicily and Sardinia, four offshore the Thyrrenian Sea and four offshore the Adriatic Sea. The study resulted in scatter diagrams, and a mapping of the energy flux in each coastal area. The average energy flux was higher for the coastlines of Sardinia and Sicily, lower for the coastlines of the Thyrrenian Sea and even lower for the coastlines of the Adriatic Sea. A comparison between wave energy and offshore wind energy conversion systems was performed in terms of initial cost, maintainance cost and performance, resulting in pay back time between 4 and 8 years depending on the systems. The wave energy farms exhibit a higher load factor than the offshore wind farms (although higher than the land wind plants). Besides, in a number of Italian regions (like Sardinia) offshore wind plants have been banned for their visual impact. On the other hand, the costs of wave power plants are higher and have not yet reached a mature stage, so that they have not yet shown all possible inconveniences. More comprehensive studies have to be performed in order to optimize the mooring technology, the energy transfer on the main land and/or conservation on site, which is an important feature for isles, for which the wave conversion systems seem to be particularly attractive.

  4. 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.

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

    SciTech Connect

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

    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.

  6. New Perspectives on Wave Energy Converter Control 

    E-print Network

    Price, Alexandra A E

    2009-01-01

    This work examines some of the fundamental problems behind the control of wave energy converters (WECs). Several new perspectives are presented to aid the understanding of the problem and the interpretation of the ...

  7. Plasma filling of high-power backward wave oscillators with nonuniform slow-wave structures

    SciTech Connect

    Grabowski, C.; Gahl, J.M.; Schamiloglu, E.

    1996-12-31

    This paper presents the first data describing experiments conducted with plasma filled, nonuniform, backward wave oscillators (BWO). Previous studies have indicated enhanced microwave power output and efficiency in plasma filled BWO`s with uniform structures. Efficiency enhancement has also been reported in vacuum BWO`s with slow wave structures having nonuniform ripple amplitude. These experiments have been conducted at the University of New Mexico (UNM) on the UNM Long-Pulse BWO Experiment. Data such as microwave power, efficiency, spectral content, and pulse duration will be presented. Details of the novel plasma injection system will also be presented including plasma parameters such as species concentration, plasma density, and temperature.

  8. 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

  9. 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

  10. 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.

  11. Investigation of suitable sites for wave energy converters around Sicily (Italy)

    NASA Astrophysics Data System (ADS)

    Iuppa, C.; Cavallaro, L.; Vicinanza, D.; Foti, E.

    2015-07-01

    An analysis of wave energy along the coasts of Sicily (Italy) is presented with the aim of selecting possible sites for the implementation of wave energy converters (WECs). The analysis focuses on the selection of hotspot areas of energy concentration. A third-generation model was adopted to reconstruct the wave data along the coast over a period of 14 years. The reconstruction was performed using the wave and wind data from the European Centre for Medium-Range Weather Forecasts. The analysis of wave energy allowed us to characterise the most energetic zones, which are located on the western side of Sicily and on the Strait of Sicily. Moreover, the estimate of the annual wave power on the entire computational domain identified eight interesting sites. The main features of the sites include relatively high wave energy and proximity to the coast, which makes them possible sites for the implementation of WEC farms.

  12. Studying Electromechanical Wave Propagation and Transport Delays in Power Systems

    NASA Astrophysics Data System (ADS)

    Dasgupta, Kalyan; Kulkarni, A. M.; Soman, Shreevardhan

    2013-05-01

    Abstract: In this paper, we make an attempt to describe the phenomenon of wave propagation when a disturbance is introduced in an electromechanical system. The focus is mainly on generator trips in a power system. Ordering of the generators is first done using a sensitivity matrix. Thereafter, orthogonal decomposition of the ordered generators is done to group them based on their participation in different modes. Finally, we find the velocity of propagation of the wave and the transport delay associated with it using the ESPRIT method. The analysis done on generators from the eastern and western regions of India.1

  13. 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.

  14. Floating type ocean wave power station equipped with hydroelectric unit

    NASA Astrophysics Data System (ADS)

    Okamoto, Shun; Kanemoto, Toshiaki; Umekage, Toshihiko

    2013-10-01

    The authors have invented the unique ocean wave power station, which is composed of the floating type platform with a pair of the floats lining up at the interval of one wave pitch and the counter-rotating type wave power unit, its runners are submerged in the seawater at the middle position of the platform. Such profiles make the flow velocity at the runner is twice faster than that of the traditional fixed/caisson type OWC, on the ideal flow conditions. Besides, the runners counter-rotate the inner and the outer armatures of the peculiar generator, respectively, and the relative rotational speed is also twice faster than the speed of the single runner/armature. Such characteristics make the runner diameter large, namely the output higher, as requested, because the torque of the power unit never act on the floating type platform. At the preliminary reseach, this paper verifies to get the power using a Wells type single runner installed in the model station. The runner takes the output which is affected by the oscillating amplitude of the platform, the rotational speed and the inertia force of the runner, etc.

  15. A Wave Scattering Theory of Solar Seismic Power Haloes

    E-print Network

    Hanasoge, Shravan M

    2009-01-01

    Spatial maps of the high-pass frequency filtered time-averaged root-mean-squared (RMS) Doppler velocities tend to show substantial decrements within regions of strong field and curiously, randomly distributed patches of enhancement in the vicinity. We propose that these haloes or enhancements are a consequence of magnetic-field-induced mode mixing (scattering), resulting in the preferential powering of waves that possess strong surface velocity signatures (i.e. scattering from low to high wavenumbers). Evidently, this process can occur in the reverse, and therefore in order to determine if the haloes are indeed caused by mode mixing, we must answer the question: {\\it how are acoustic waves scattered by magnetic fields?} Through simulations of the interactions between waves and sunspots and models of plage, we demonstrate that the high to low modal order scattering channels are favoured. With increasing frequency and consequently, decreasing wavelength, a growing number of modes are scattered by the sunspot, t...

  16. 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.

  17. Efficiency enhancement in high power backward-wave oscillators

    SciTech Connect

    Goebel, D.M.; Feicht, J.R. Adler, E.A. ); Ponti, E.S. ); Eisenhart, R.L. ); Lemke, R.W. )

    1999-06-01

    High power microwave (HPM) sources based on the backward-wave oscillator (BWO) have been investigated for the past two decades primarily because of their potential for very high efficiency (15 to 40%) operation. Several different effects have been proposed to explain this high efficiency compared to conventional BWO's. One of the major contributors to the high efficiency of the plasma-filled Pasotron HPM BWO source is the presence of optimally phased end reflections. The Pasotron uses a long pulse ([ge]100 [micro]s) plasma-cathode electron-gun and plasma-filled slow-wave structure to produce microwave pulses in the range of 1 to 10 MW without the use of externally produced magnetic fields. The efficiency of the Pasotron can be enhanced by up to a factor of two when the device is configured as a standing-wave oscillator in which properly phased reflections from the downstream collector end of the finite length SWS constructively interfere with the fundamental backward-wave modes and improve the coupling of the beam to the circuit. Operation in this configuration increases the efficiency up to 30% but causes the frequency to vary in discrete steps and the output power to change strongly with beam parameters and oscillation frequency.

  18. A powerful reflector in relativistic backward wave oscillator

    SciTech Connect

    Cao, Yibing Sun, Jun; Teng, Yan; Zhang, Yuchuan; Zhang, Lijun; Shi, Yanchao; Ye, Hu; Chen, Changhua

    2014-09-15

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

  19. 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 ...

  20. Sorting and Parameterization of Observed Saturn and Jupiter Chorus Wave Power

    NASA Astrophysics Data System (ADS)

    Menietti, Douglas; Horne, Richard; Shprits, Yuri; Woodfield, Emma; Groene, Joseph; Hospodarsky, George; Gurnett, Donald

    2014-05-01

    Recent work has shown that whistler mode chorus waves can accelerate electrons to MeV energies outside the orbit of the moon Io. These particles then form the source of Jupiter's radiation belts which peak near L=1.5. The wave acceleration process depends on the distribution of chorus wave power in frequency, local time, latitude and also on the plasma density. In this study we bin the chorus power spectral density observed by the Cassini radio and plasma wave science investigation (RPWS) at Saturn and the Galileo plasma wave investigation (PWS) at Jupiter. The spatial bins include L-shell (based on models), latitude, and local time. Within each spatial bin we calculate the mean power-versus-frequency profile (for upper and lower bands relative to the electron cyclotron frequency) which can then be fit to a guassian. One goal of the study is to provide a database for use in quasilinear models requiring the calculation of diffusion coefficients. In this report we present our initial findings.

  1. 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.

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

    SciTech Connect

    Wu, Jinyuan; 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.

  3. 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 .

  4. Jupiter's Tropospheric Thermal Emission. II. Power Spectrum Analysis and Wave Search

    NASA Astrophysics Data System (ADS)

    Harrington, Joseph; Dowling, Timothy E.; Baron, Richard L.

    1996-11-01

    We study power spectra and search for planetary waves in images of Jupiter's cloud opacity. The observation wavelength of 4.9 ?m senses thermal emission from the ?5-bar level; overlying clouds attenuate the emission. Our companion paper (J. Harrington, T. E. Dowling, and R. L. Baron, 1996,Icarus124, 22-31) describes 19 nights of observations (6 with 360° longitude coverage) and new reduction techniques. Atmospheric seeing limits resolution to ?2500 km. Zonal power spectral density at planetary wavenumbers higher than ?25 follows a power law in the wavenumber. Eastward jet-power laws average -2.71 ± 0.07 and westward jet-power laws, excluding cloud-obscured regions, average -3.14 ± 0.12. Wavenumbers 1-24 roughly follow power laws near -0.7 for both jet directions, but with many superposed discrete features. The meridional spectrum similarly breaks around wavenumber 25, with power law trends of -0.36 and -3.27. However, a pattern of undulations is superposed over its linear trends. L. D. Travis (1978,J. Atmos. Sci.35, 1584-1595) established an empirical correspondence between power spectra of atmospheric kinetic energy and those of cloud opacities for the Earth and analyzed Venus cloud data under this assumption. We do the same for Jupiter. If the Rossby deformation radius,Ld, were an energy input scale, as baroclinic instability theory predicts, one would expect energy and enstrophy cascades (power laws of -5/3 and -3, respectively) on opposite sides of the wavenumber corresponding toLd. If the top of our high-wavenumber power law isLd, its value is ?2100 km at 45° latitude. Our spectra show persistent features with phases moving linearly over the 99-day observation period. Some of these can be identified with periodic features such as vortex chains and the equatorial plumes. The origin of others is less certain. We present a table of our best wave candidates.

  5. 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.

  6. Pulse shortening in a high power backward wave oscillator

    SciTech Connect

    Gahl, J.M.; Grabowski, C.; Young, D.; Ishihara, O.

    1996-12-31

    This paper describes an experimental and theoretical investigation specifically oriented to revealing the various physical phenomena responsible for pulse shortening in a high power backward wave oscillator (BWO). Pulse shortening is common among all long-pulse, electron beam-driven, high power microwave sources. Therefore, data obtained in the course of these investigations should be applicable to a variety of high power microwave sources. Recent experiments, specific to the investigation of pulse shortening, have involved using a collector with a small aperture at varying radii to monitor the beam current profile at different radii as a function of time. These results are correlated with the initiation and cessation of the microwave pulses in separate experiments. PIC simulations are being performed to investigate the causes of beam profile variation and to suggest possible remedies. The paper will present the most recent experimental and theoretical results, as well as plans for future diagnostic development and theoretical investigation.

  7. Modern Microwave and Millimeter-Wave Power Electronics

    NASA Astrophysics Data System (ADS)

    Barker, Robert J.; Luhmann, Neville C.; Booske, John H.; Nusinovich, Gregory S.

    2005-04-01

    A comprehensive study of microwave vacuum electronic devices and their current and future applications While both vacuum and solid-state electronics continue to evolve and provide unique solutions, emerging commercial and military applications that call for higher power and higher frequencies to accommodate massive volumes of transmitted data are the natural domain of vacuum electronics technology. Modern Microwave and Millimeter-Wave Power Electronics provides systems designers, engineers, and researchers-especially those with primarily solid-state training-with a thoroughly up-to-date survey of the rich field of microwave vacuum electronic device (MVED) technology. This book familiarizes the R&D and academic communities with the capabilities and limitations of MVED and highlights the exciting scientific breakthroughs of the past decade that are dramatically increasing the compactness, efficiency, cost-effectiveness, and reliability of this entire class of devices. This comprehensive text explores a wide range of topics: * Traveling-wave tubes, which form the backbone of satellite and airborne communications, as well as of military electronic countermeasures systems * Microfabricated MVEDs and advanced electron beam sources * Klystrons, gyro-amplifiers, and crossed-field devices * "Virtual prototyping" of MVEDs via advanced 3-D computational models * High-Power Microwave (HPM) sources * Next-generation microwave structures and circuits * How to achieve linear amplification * Advanced materials technologies for MVEDs * A Web site appendix providing a step-by-step walk-through of a typical MVED design process Concluding with an in-depth examination of emerging applications and future possibilities for MVEDs, Modern Microwave and Millimeter-Wave Power Electronics ensures that systems designers and engineers understand and utilize the significant potential of this mature, yet continually developing technology. SPECIAL NOTE: All of the editors' royalties realized from the sale of this book will fund the future research and publication activities of graduate students in the vacuum electronics field.

  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. Artificial airglow excited by high-power radio waves.

    PubMed

    Bernhardt, P A; Duncan, L M; Tepley, C A

    1988-11-18

    High-power electromagnetic waves beamed into the ionosphere from ground-based transmitters illuminate the night sky with enhanced airglow. The recent development of a new intensified, charge coupled-device imager made it possible to record optical emissions during ionospheric heating. Clouds of enhanced airglow are associated with large-scale plasma density cavities that are generated by the heater beam. Trapping and focusing of electromagnetic waves in these cavities produces accelerated electrons that collisionally excite oxygen atoms, which emit light at visible wavelengths. Convection of plasma across magnetic field lines is the primary source for horizontal motion of the cavities and the airglow enhancements. During ionospheric heating experiments, quasi-cyclic formation, convection, dissipation and reappearance of the cavites comprise a major source of long-term variability in plasma densities during ionospheric heating experiments. PMID:17834046

  10. 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.

  11. RF breakdown experiments in "cold" slow wave structures under experimental circumstances of high power microwaves

    NASA Astrophysics Data System (ADS)

    Zhang, Dian; Zhang, Jun; Jin, Zhenxing; Yang, Jianhua; Zhong, Huihuang; Zhou, Shengyue

    2015-07-01

    RF breakdown tests in "cold" slow wave structures (SWSs) are executed under experimental circumstance of high power microwave (HPM). All the SWSs under tests are made of stainless steel and are designed as traveling wave structures, which operate at ?/2 mode of TM01 wave. The "cold" SWSs are fed by an X-band overmoded relativistic backward wave oscillator, which generates TM01 mode at 9.46 GHz with power around 1.8 GW, pulse duration about 100 ns, and repetition rate of 30 Hz. In the tests, the variances of peak surface electric field (Es-max, 0.53 MV/cm-1.79 MV/cm), number of periods (2-6 periods) of SWSs, and external magnetic field (Bext, 0-2.5 T) versus RF breakdown effects are recorded. The tests results indicate that the input microwave energy is mainly absorbed, not reflected by the RF breakdown process in traveling wave SWSs. Both larger magnitude of Es-max and more numbers of periods of SWSs aggravate the microwave absorption in the breakdown process and bring about shorter transmission pulse width. However, little correlation between RF breakdown effects and Bext is observed in the tests. Further theoretical and experimental studies would be helpful for understanding of the effects of Bext on RF breakdown and breakdown mechanisms under the experimental circumstances of HPM sources.

  12. Structural Optimization of Triboelectric Nanogenerator for Harvesting Water Wave Energy.

    PubMed

    Jiang, Tao; Zhang, Li Min; Chen, Xiangyu; Han, Chang Bao; Tang, Wei; Zhang, Chi; Xu, Liang; Wang, Zhong Lin

    2015-12-22

    Ocean waves are one of the most abundant energy sources on earth, but harvesting such energy is rather challenging due to various limitations of current technologies. Recently, networks formed by triboelectric nanogenerator (TENG) have been proposed as a promising technology for harvesting water wave energy. In this work, a basic unit for the TENG network was studied and optimized, which has a box structure composed of walls made of TENG composed of a wavy-structured Cu-Kapton-Cu film and two FEP thin films, with a metal ball enclosed inside. By combination of the theoretical calculations and experimental studies, the output performances of the TENG unit were investigated for various structural parameters, such as the size, mass, or number of the metal balls. From the viewpoint of theory, the output characteristics of TENG during its collision with the ball were numerically calculated by the finite element method and interpolation method, and there exists an optimum ball size or mass to reach maximized output power and electric energy. Moreover, the theoretical results were well verified by the experimental tests. The present work could provide guidance for structural optimization of wavy-structured TENGs for effectively harvesting water wave energy toward the dream of large-scale blue energy. PMID:26567754

  13. 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

  14. Analysis of microwave interference switches with distributed power of switched wave and plasma gas-discharge switching

    NASA Astrophysics Data System (ADS)

    Artemenko, S. N.; Avgustinovich, V. A.; Gorev, S. A.; Igumnov, V. S.

    2015-11-01

    This paper reports on development of effective cascade type microwave interference switches using waveguide H-tees providing total transition attenuation value of about -50dB at the non-transmitting state, the power losses of -2-3dB at the transmitting state, and the working power compared to the one of a regular waveguide. These switches have different types of connections of two or three H-tees. Different designs provide different distributions of switched wave power between tees and provide different power levels of the switched wave. Characteristics of the switches made of tees matched from their side arms and of unmatched ones were calculated using the scattering matrix method. It was shown the matched tees used in the design allow decreasing by several times the power level of the switched wave and that increases the operating power and stability of the switching process. While some definite combination of unmatched tees allow increasing the power level of the switched wave and may provide effective switching of the transmitted wave at decreased power level. It was shown experimentally the cascade switches could be used as effective energy extraction device in an active resonant microwave compressor also.

  15. Numerical Modeling of Fluid Structure Interactions of a Floating Wave Energy Extraction Device

    NASA Astrophysics Data System (ADS)

    Lee, J.; Kang, S.

    2014-12-01

    In recent years there has been increased attention towards developing the strategies for harnessing hydrokinetic and wave energy from the ocean. There exists several hydrokinetic energy devices designed to extract energy from the ocean current but few wave energy devices are available. The moored floating cylinder-like structure that has been recently developed in South Korea is one of such devices. We carry out numerical simulation of the three-dimensional interactions of a floating cylinder and incoming waves using the level-set curvilinear immersed boundary method of Kang and Sotiropoulos (2012) to improve the understanding the wave energy extraction mechanisms of that device. The results demonstrate the potential of our numerical model as a powerful engineering tool for predicting complex wave-structure interaction phenomena associated with energy extraction devices.

  16. 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…

  17. 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.

  18. 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.

  19. High-power pulse trains excited by modulated continuous waves

    E-print Network

    Wang, Yan; Li, Lu; Malomed, Boris A

    2015-01-01

    Pulse trains growing from modulated continuous waves (CWs) are considered, using solutions of the Hirota equation for solitons on a finite background. The results demonstrate that pulses extracted from the maximally compressed trains can propagate preserving their shape and forming robust arrays. The dynamics of double high-power pulse trains produced by modulated CWs in a model of optical fibers, including the Raman effect and other higher-order terms, is considered in detail too. It is demonstrated that the double trains propagate in a robust form, with frequencies shifted by the Raman effect.

  20. Experimental results using active control of traveling wave power flow

    NASA Technical Reports Server (NTRS)

    Miller, David W.; Hall, Steven R.

    1991-01-01

    Active structural control experiments conducted on a 24-ft pinned-free beam derived feedback compensators on the basis of a traveling-wave approach. A compensator is thus obtained which eliminates resonant behavior by absorbing all impinging power. A causal solution is derived for this noncausal compensator which mimics its behavior in a given frequency range, using the Wiener-Hopf. This optimal Wiener-Hopf compensator's structure-damping performance is found to exceed any obtainable by means of rate feedback. Performance limitations encompassed the discovery of frequencies above which the sensor and actuator were no longer dual and an inadvertent coupling of the control hardware to unmodeled structure torsion modes.

  1. High-power terahertz-wave generation using DAST crystal and detection using mid-infrared powermeter.

    PubMed

    Suizu, Koji; Miyamoto, Katsuhiko; Yamashita, Tomoyu; Ito, Hiromasa

    2007-10-01

    The exact power output of a table-top-sized terahertz (THz)-wave source using a nonlinear optical process has not been clarified because detectors for these experiments [Si bolometer, deuterated triglycine sulfate (DTGS), etc.] are not calibrated well. On the other hand, powermeters for the mid-infrared (mid-IR) region are well established and calibrated. We constructed a high-power dual-wavelength optical parametric oscillator with two KTP crystals as a light source for difference frequency generation. The obtained powers of dual waves were 21 mJ at ~1300 nm, ten times higher than that of the previous measurement. The device provides high-power THz-wave generation with ~100 times greater output power than that reported in previous works. A well-calibrated mid-IR powermeter at ~27 THz detected the generated THz wave; its measured energy was 2.4 microJ. Although the powermeter had no sensitivity in the lower-frequency range (below 20 THz), the pulse energy at such a low-frequency region was estimated in reference to the output spectrum obtained using a DTGS detector: the energy would be from about the submicrojoule level to a few microjoules in the THz-wave region. PMID:17909606

  2. 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.

  3. Shock wave generated by high-energy electric spark discharge

    NASA Astrophysics Data System (ADS)

    Liu, Qingming; Zhang, Yunming

    2014-10-01

    Shock wave generated by electric spark discharge was studied experimentally and the shock wave energy was evaluated in this paper. A pressure measurement system was established to study the pressure field of the electric spark discharge process. A series of electric spark discharge experiments were carried out and the energy of the electric spark used in present study was in the range of 10 J, 100 J, and 1000 J, respectively. The shock wave energy released from the electric spark discharge process was calculated by using the overpressure values at different measurement points near the electric spark discharge center. The good consistency of shock wave energies calculated by pressure histories at different measuring points in the same electric spark discharge experiment illustrates the applicability of the weak shock wave theory in calculating the energy of shock wave induced by electric spark discharge process. The result showed that shock wave formed at the initial stage of electric spark discharge process, and the shock wave energy is only a little part of electric spark energy. From the analysis of the shock wave energy and electric spark energy, a good linear relationship between shock wave energy and electric spark energy was established, which make it possible to calculate shock wave energy by measuring characteristic parameters of electric spark discharge process instead of shock wave. So, the initiation energy of direct initiation of detonation can be determined easily by measuring the parameters of electric spark discharge process.

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

    SciTech Connect

    Lee, Frank M.; Morrison, P. J.; Paoletti, M. S.; Swinney, Harry L.

    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.

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

    SciTech Connect

    Holzrichter, J.F.; Burnett, G.C.; Ng, L.C.; Lea, W.A.

    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.}

  6. Direct Drive Wave Energy Buoy

    SciTech Connect

    Rhinefrank, Ken

    2011-11-02

    Presentation from the 2011 Water Peer Review in which principal investigator discusses project progress and results for this project which will be used to inform the utility-scale design process, improve cost estimates, accurately forecast energy production and to observe system operation and survivability.

  7. Power and Energy of Exploding Wires

    NASA Astrophysics Data System (ADS)

    Valancius, Cole

    2015-06-01

    Exploding wires are used in many high-energy applications, such as initiating explosives. Analysis of gold wire burst in detonator applications has shown Burst Current and Action metrics to be incapable of explaining burst phenomenon as the inductance of a firing circuit is changed. Energy Density better captures the correlation between different wire geometries, different electrical inputs, and explosive initiation. This idea has been expanded upon, to analyze the burst properties in Power-Energy space. Further inconsistencies in the understanding of wire burst and its relation to peak voltage have been found. An argument will be made for redefining the definition of burst. The result is a more broad understanding of rapid metal phase transition and the physical applications of the released shock wave.

  8. 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.

  9. Input Power Requirements for High-Frequency Gravitational Wave Generators

    NASA Astrophysics Data System (ADS)

    Baker, Robert M. L.

    2009-03-01

    An analysis is accomplished of the input power requirement of High-Frequency Gravitational Wave (HFGW) generators. Several techniques are explored using both off-the-shelf and advanced-nanotechnology generator elements. It is concluded that proof-of-concept test, involving N off-the-shelf array elements could be of meter to kilometer length and require 25 MW or less power if array elements are in a staggered arrangement. The power and size of an operational nanotechnology HFGW generator or transmitter device can be greatly reduced by the focusing effect of N2 radiator pairs. Utilization of conventional piezoelectric Film Bulk Acoustic Resonators (FBARs), tailored and scaled for HFGW generation, could provide the initial commercial generation means. The use of the new infrared-energized ring concept of Woods and the use of a double helix array proposed by Baker may even further reduce the power and size requirements of the device to <<20 W and mm in length and width.

  10. 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.

  11. 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.

  12. 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.; Smith, Charles W.; Isenberg, Philip A.; Vasquez, Bernard J.; Joyce, Colin J.; Murphy, Neil; Nuno, Raquel G. E-mail: Charles.Smith@unh.edu E-mail: Bernie.Vasquez@unh.edu E-mail: Neil.Murphy@jpl.nasa.gov

    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.

  13. 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.

  14. INTERNAL WAVES: MODELING ENERGY DISPERSION AT THE OCEAN'S SURFACE

    E-print Network

    Qiu, Bo

    INTERNAL WAVES: MODELING ENERGY DISPERSION AT THE OCEAN'S SURFACE A THESIS SUBMITTED TO THE GLOBAL(s) Glenn S. Carter #12;iii ABSTRACT Using the Princeton Ocean Model, internal waves are generated to determine how the internal wave energy rays interact with the pycnocline. Based on the output from POM

  15. 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.

  16. Optical Gravitational Wave Antenna with Increased Power Handling Capability

    E-print Network

    Matsko, Andrey B; Yamamoto, Hiroaki; Vyatchanin, Sergey P

    2015-01-01

    Fundamental sensitivity of an optical interferometric gravitational wave detector increases with increase of the optical power which, in turn, limited because of the opto-mechanical parametric instabilities of the interferometer. We propose to optimize geometrical shape of the mirrors of the detector to reduce the diffraction-limited finesse of unessential optical modes of the interferometer resulting in increase of the threshold of the opto-mechanical instabilities and subsequent increase of the measurement sensitivity. Utilizing parameters of the LIGO interferometer we found that the proposed technique allows constructing a Fabry-Perot interferometer with round trip diffraction loss of the fundamental mode not exceeding $5$~ppm, whereas the loss of the first dipole as well as the other high order modes exceed $1,000$~ppm and $8,000$~ppm, respectively. The optimization comes at the price of tighter tolerances on the mirror tilt stability, but does not result in a significant modification of the optical beam ...

  17. Underwater Sound Levels at a Wave Energy Device Testing Facility in Falmouth Bay, UK.

    PubMed

    Garrett, Joanne K; Witt, Matthew J; Johanning, Lars

    2016-01-01

    Passive acoustic monitoring devices were deployed at FaBTest in Falmouth Bay, UK, a marine renewable energy device testing facility during trials of a wave energy device. The area supports considerable commercial shipping and recreational boating along with diverse marine fauna. Noise monitoring occurred during (1) a baseline period, (2) installation activity, (3) the device in situ with inactive power status, and (4) the device in situ with active power status. This paper discusses the preliminary findings of the sound recording at FabTest during these different activity periods of a wave energy device trial. PMID:26610976

  18. A low-cost float method of harnessing wave energy

    SciTech Connect

    George, M.P.

    1983-12-01

    The author proposes in this paper a low-cost and simple method of harnessing wave energy that should enable coastal regions to be self-sufficient in electric power. The method is eminently applicable to India and such developing countries, being simple and involving a small capital investment. The method was evolved after study of the Indian West Coast fronting the Arabian Sea, and can harness about 50% of the wave energy. A log of wood about 5 metres long and 50 cm. in diameter, having a specific gravity of 0.8 to 0.9, is made to float parallel to the beach and about 50 metres away from it. Its movement is restricted to the vertical plane by means of poles. Two roller chains are attached to the ends of the log which pass over two sprocket free-wheels. When the log is lifted with the crest of the wave, the roller chain moves over the free-wheel. When the trough of the wave reaches the log, its weight is applied to the sprocket wheels through the roller chains. Each sprocket wheel rotates and the rotation is multiplied with a gear wheel. The torque from the high speed spindle of the gear is applied to a small alternating current generator. The AC output from the generator is rectified and used either for charging a battery bank, or connected to the lighting system, or supplied to electrolytic tank for producing hydrogen and other chemicals at the site. A chain of such systems along the coast can supply enough power to light the fishermen's hamlets stretching along the coast.

  19. 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

  20. Energy Industry Powers CTE Program

    ERIC Educational Resources Information Center

    Khokhar, Amy

    2012-01-01

    Michael Fields is a recent graduate of Buckeye Union High School in Buckeye, Arizona. Fields is enrolled in the Estrella Mountain Community College (EMCC) Get Into Energy program, which means he is well on his way to a promising career. Specializing in power plant technology, in two years he will earn a certificate that will all but guarantee a…

  1. Power Amplifier Module with 734-mW Continuous Wave Output Power

    NASA Technical Reports Server (NTRS)

    Fung, King Man; Samoska, Lorene A.; Kangaslahti, Pekka P.; Lamgrigtsen, Bjorn H.; Goldsmith, Paul F.; Lin, Robert H.; Soria, Mary M.; Cooperrider, Joelle T.; Micovic, Moroslav; Kurdoghlian, Ara

    2010-01-01

    Research findings were reported from an investigation of new gallium nitride (GaN) monolithic millimeter-wave integrated circuit (MMIC) power amplifiers (PAs) targeting the highest output power and the highest efficiency for class-A operation in W-band (75-110 GHz). W-band PAs are a major component of many frequency multiplied submillimeter-wave LO signal sources. For spectrometer arrays, substantial W-band power is required due to the passive lossy frequency multipliers-to generate higher frequency signals in nonlinear Schottky diode-based LO sources. By advancing PA technology, the LO system performance can be increased with possible cost reductions compared to current GaAs PAs. High-power, high-efficiency GaN PAs are cross-cutting and can enable more efficient local oscillator distribution systems for new astrophysics and planetary receivers and heterodyne array instruments. It can also allow for a new, electronically scannable solid-state array technology for future Earth science radar instruments and communications platforms.

  2. Internal energy relaxation in shock wave structure

    SciTech Connect

    Josyula, Eswar Suchyta, Casimir J.; Boyd, Iain D.; Vedula, Prakash

    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.

  3. A Low-Power System Design for Lamb Wave Methods Shaver Deyerlea

    E-print Network

    Ha, Dong S.

    A Low-Power System Design for Lamb Wave Methods Shaver Deyerlea , Dong Sam Haa , and Daniel J-to-digital converter (ADC) of a Lamb wave system samples a response signal and converts it into a digital signal for further processing in the digital domain. A typical ADC used for a Lamb wave system consumes a large

  4. Journal of Power Sources xxx (2005) xxxxxx POWER (power optimization for wireless energy requirements): A

    E-print Network

    Sastry, Ann Marie

    2005-01-01

    Journal of Power Sources xxx (2005) xxx­xxx POWER (power optimization for wireless energy expanded and implemented an algorithm for selecting power supplies into a turnkey MATLAB code, "POWER" (power optimization for wireless energy requirements). Our algorithm uses three approaches to system

  5. Journal of Power Sources 159 (2006) 758780 POWER (power optimization for wireless energy requirements): A

    E-print Network

    Sastry, Ann Marie

    2006-01-01

    Journal of Power Sources 159 (2006) 758­780 POWER (power optimization for wireless energy December 2005 Abstract We have expanded and implemented an algorithm for selecting power supplies into a turnkey MATLAB code, "POWER" (power optimization for wireless energy requirements). Our algorithm uses

  6. High-power millimeter-wave rotary joint

    NASA Astrophysics Data System (ADS)

    Chang, T. H.; Yu, B. R.

    2009-03-01

    The rotary joint is a useful microwave component that connects a fixed part to a rotatable part. This study systematically analyzes the effect of the discontinuity on the interface of a rotary joint for several waveguide modes. Simulation results indicate that the transmission of the TE01 mode is independent of the geometry of the joint, and thus is ideal for such application. A rotary joint consisting of two identical TE01 mode converters, clasped each other by a bearing, is designed, fabricated, and tested. Back-to-back transmission measurements exhibit an excellent agreement to the results of computer simulations. The measured optimum transmission is 97% with a 3 dB bandwidth of 8.5 GHz, centered at 35.0 GHz. The cold measurement shows that the results are independent of the angle of rotation. In addition, a high-power experiment is conducted. The just developed rotary joint can operate up to a peak input power of 210 W with a duty of 18%. The working principle, although demonstrated in the millimeter-wave region, can be applied up to the terahertz region where the joint gap is generally critical except for the operating TE01 mode.

  7. 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.

  8. 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).

  9. Distributed Power Delivery for Energy Efficient and Low Power Systems

    E-print Network

    Friedman, Eby G.

    Distributed Power Delivery for Energy Efficient and Low Power Systems Selc¸uk K¨ose Department are needed to determine the location of these on-chip power supplies and decoupling capacitors. In this paper, the optimal location of the power supplies and decoupling capacitors is determined for different size

  10. Experimental study of a wave energy scavenging system onboard autonomous surface vessels (ASVs)

    E-print Network

    Experimental study of a wave energy scavenging system onboard autonomous surface vessels (ASVs) J potential. The spectrum of current ASVs ranges from systems that have a high onboard power capacity for fast speeds and significant onboard capability through to long range endurance ASVs that harvest marine energy

  11. 78 FR 40132 - Wave Energy Converter Prize Administration Webinar

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-07-03

    ... of Energy Efficiency and Renewable Energy Wave Energy Converter Prize Administration Webinar AGENCY: Office of Energy Efficiency and Renewable Energy (EERE), U.S. Department of Energy (DOE). ACTION: Notice... available for public review on the DOE Office of Energy Efficiency and Renewable Energy (EERE) Web site...

  12. 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.

  13. Gravitational Waves, Dark Energy and Inflation

    NASA Astrophysics Data System (ADS)

    Ni, Wei-Tou

    In this paper we first present a complete classification of gravitational waves according to their frequencies: (i) Ultra high frequency band (above 1 THz); (ii) Very high frequency band (100 kHz-1 THz); (iii) High frequency band (10 Hz-100 kHz); (iv) Middle frequency band (0.1 Hz-10 Hz); (v) Low frequency band (100 nHz-0.1 Hz); (vi) Very low frequency band (300 pHz-100 nHz); (vii) Ultra low frequency band (10 fHz-300 pHz); (viii) Hubble (extremely low) frequency band (1 aHz-10 fHz); (ix) Infra-Hubble frequency band (below 1 aHz). After briefly discussing the method of detection for different frequency bands, we review the concept and status of space gravitational-wave missions — LISA, ASTROD, ASTROD-GW, Super-ASTROD, DECIGO and Big Bang Observer. We then address to the determination of dark energy equation, and probing the inflationary physics using space gravitational wave detectors.

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

    SciTech Connect

    Prager, James; Winglee, Robert; Roberson, B. Race; Ziemba, Timothy

    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.

  15. Arterial wave propagation phenomena, ventricular work, and power dissipation.

    PubMed

    Berger, D S; Li, J K; Noordergraaf, A

    1995-01-01

    The effects of wave propagation phenomena, namely global reflection coefficient (gamma G[omega]) and pulse wave velocity (Cph), are studied in a model of the coupled left ventricle/arterial system. The left ventricle consists of a time-varying elastance, while the arterial system is modeled as a single, uniform, elastic tube terminating in a complex load. Manipulation of model parameters allowed for the precise control of gamma G(omega) and Cph independent of each other, peripheral resistance, and characteristic impedance. Reduction of gamma G(omega) and Cph were achieved through increases in load compliance and tube compliance, respectively. The equations describing the system were solved for left ventricular and aortic pressures and aortic flow. From these, stroke volume (SV), left ventricular stroke work (SW), and steady (Ws), oscillatory (Wo), and total power dissipation (Wt) in the arterial system were calculated. An index of arterial system efficiency was the ratio Wo/Wt (%Wo), with lower values indicating higher efficiency. Reduction of gamma G(omega) yielded initial increases in Ws, while Wo increased for the entire range of gamma G(omega), resulting in increased %Wo. This reduced efficiency is imposed on the ventricle, resulting in increased SW without increased SV. On the other hand, decreased Cph yielded in a steady increase in Ws and a biphasic response in Wo, resulting in reduced %Wo for most of the range of reduced Cph. These results suggest that differential effects on arterial system efficiency can result from reductions of gamma G(omega) and Cph. In terms of compliance, changes in arterial compliance can have different effects on efficiency, depending on where the compliance change takes place. Reasons for these results are suggested, and the role of distributed compliances is raised as a new problem. PMID:8572430

  16. Scattered surface wave energy in the seismic coda

    USGS Publications Warehouse

    Zeng, Y.

    2006-01-01

    One of the many important contributions that Aki has made to seismology pertains to the origin of coda waves (Aki, 1969; Aki and Chouet, 1975). In this paper, I revisit Aki's original idea of the role of scattered surface waves in the seismic coda. Based on the radiative transfer theory, I developed a new set of scattered wave energy equations by including scattered surface waves and body wave to surface wave scattering conversions. The work is an extended study of Zeng et al. (1991), Zeng (1993) and Sato (1994a) on multiple isotropic-scattering, and may shed new insight into the seismic coda wave interpretation. The scattering equations are solved numerically by first discretizing the model at regular grids and then solving the linear integral equations iteratively. The results show that scattered wave energy can be well approximated by body-wave to body wave scattering at earlier arrival times and short distances. At long distances from the source, scattered surface waves dominate scattered body waves at surface stations. Since surface waves are 2-D propagating waves, their scattered energies should in theory follow a common decay curve. The observed common decay trends on seismic coda of local earthquake recordings particular at long lapse times suggest that perhaps later seismic codas are dominated by scattered surface waves. When efficient body wave to surface wave conversion mechanisms are present in the shallow crustal layers, such as soft sediment layers, the scattered surface waves dominate the seismic coda at even early arrival times for shallow sources and at later arrival times for deeper events.

  17. 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.

  18. ENergy and Power Evaluation Program

    SciTech Connect

    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. Two-wave high-power CO2 laser

    NASA Astrophysics Data System (ADS)

    Burtsev, V. A.; Vasilevskii, M. A.; Koziuchenok, S. S.; Rodichkin, V. A.; Roife, I. M.; Stekolnikov, B. A.; Tomashevich, V. P.; Shanskii, V. F.

    1983-12-01

    The design and operation of a high-power CO2 laser operating at 10.6 and 9.6 microns are reported. The device comprises two electron-gun/discharge chamber modules separated by a cell filled with SF6; the 200-keV electron guns are supplied by a three-stage matched voltage-pulse generator with a sequential correction circuit and deliver 2.5-microsec pulses of current density greater than 1 A/sq cm to the discharge chamber through a 10 x 60-cm window covered with 30-micron-thick Al foil. At SF6 pressure 4.2 torr, the energies at 10.6 and 9.6 microns are equal and a peak power of about 5.5 GW is achieved.

  20. 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.

  1. Exploring Energy, Power, and Transportation Technology.

    ERIC Educational Resources Information Center

    Bowers, Donovan; Kellum, Mary

    These teacher's materials for a seven-unit course were developed to help students develop technological literacy, career exploration, and problem-solving skills relative to the communication industries. The seven units include an overview of energy and power, principles of energy and power, power production and conversion, power transmission and…

  2. High power millimeter wave experiment of ITER relevant electron cyclotron heating and current drive system.

    PubMed

    Takahashi, K; Kajiwara, K; Oda, Y; Kasugai, A; Kobayashi, N; Sakamoto, K; Doane, J; Olstad, R; Henderson, M

    2011-06-01

    High power, long pulse millimeter (mm) wave experiments of the RF test stand (RFTS) of Japan Atomic Energy Agency (JAEA) were performed. The system consists of a 1 MW/170 GHz gyrotron, a long and short distance transmission line (TL), and an equatorial launcher (EL) mock-up. The RFTS has an ITER-relevant configuration, i.e., consisted by a 1 MW-170 GHz gyrotron, a mm wave TL, and an EL mock-up. The TL is composed of a matching optics unit, evacuated circular corrugated waveguides, 6-miter bends, an in-line waveguide switch, and an isolation valve. The EL-mock-up is fabricated according to the current design of the ITER launcher. The Gaussian-like beam radiation with the steering capability of 20°-40° from the EL mock-up was also successfully proved. The high power, long pulse power transmission test was conducted with the metallic load replaced by the EL mock-up, and the transmission of 1 MW/800 s and 0.5 MW/1000 s was successfully demonstrated with no arcing and no damages. The transmission efficiency of the TL was 96%. The results prove the feasibility of the ITER electron cyclotron heating and current drive system. PMID:21721690

  3. Reference Model 6 (RM6): Oscillating Wave Energy Converter.

    SciTech Connect

    Bull, Diana L; Smith, Chris; Jenne, Dale Scott; Jacob, Paul; Copping, Andrea; Willits, Steve; Fontaine, Arnold; Brefort, Dorian; Gordon, Margaret Ellen; Copeland, Robert; Jepsen, Richard A.

    2014-10-01

    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 reference model design in a complementary manner to Reference Models 1-4 contained in the above report. In this report, a conceptual design for an Oscillating Water Column Wave Energy Converter (WEC) device appropriate for the modeled reference resource site was identified, and a detailed backward bent duct buoy (BBDB) device design was developed using a combination of numerical modeling tools and scaled physical models. Our team used the methodology in SAND2013-9040 for the economic analysis that included costs for designing, manufacturing, deploying, and operating commercial-scale MEC arrays, up to 100 devices. The methodology was applied to identify key cost drivers and to estimate levelized cost of energy (LCOE) for this RM6 Oscillating Water Column device in dollars per kilowatt-hour (%24/kWh). Although many costs were difficult to estimate at this time due to the lack of operational experience, the main contribution of this work was to disseminate a detailed set of methodologies and models that allow for an initial cost analysis of this emerging technology. This project is sponsored by the U.S. Department of Energy's (DOE) Wind and Water Power Technologies Program Office (WWPTO), within the Office of Energy Efficiency & Renewable Energy (EERE). Sandia National Laboratories, the lead in this effort, collaborated with partners from National Laboratories, industry, and universities to design and test this reference model.

  4. Wave energy and wave-induced flow reduction by full-scale model Posidonia oceanica seagrass

    NASA Astrophysics Data System (ADS)

    Manca, E.; Cáceres, I.; Alsina, J. M.; Stratigaki, V.; Townend, I.; Amos, C. L.

    2012-12-01

    This paper presents results from experiments in a large flume on wave and flow attenuation by a full-scale artificial Posidonia oceanica seagrass meadow in shallow water. Wave height and in-canopy wave-induced flows were reduced by the meadow under all tested regular and irregular wave conditions, and were affected by seagrass density, submergence and distance from the leading edge. The energy of irregular waves was reduced at all components of the spectra, but reduction was greater at the peak spectral frequency. Energy dissipation factors were largest for waves with small orbital amplitudes and at low wave Reynolds numbers. An empirical model, commonly applied to predict friction factors by rough beds, proved applicable to the P. oceanica bed. However at the lowest Reynolds numbers, under irregular waves, the data deviated significantly from the model. In addition, the wave-induced flow dissipation in the lower canopy increased with increasing wave orbital amplitude and increasing density of the mimics. The analysis of the wave-induced flow spectra confirm this trend: the reduction of flow was greatest at the longer period component of the spectra. Finally, we discuss the implications of these findings for sediment dynamics and the role of P. oceanica beds in protecting the shore from erosion.

  5. A Novel Multimode Waveguide Coupler for Accurate Power Measurement of Traveling Wave Tube Harmonic Frequencies

    NASA Technical Reports Server (NTRS)

    Wintucky, Edwin G.; Simons, Rainee N.

    2014-01-01

    This paper presents the design, fabrication and test results for a novel waveguide multimode directional coupler (MDC). The coupler fabricated from two dissimilar waveguides is capable of isolating the power at the second harmonic frequency from the fundamental power at the output port of a traveling-wave tube (TWT). In addition to accurate power measurements at harmonic frequencies, a potential application of the MDC is in the design of a beacon source for atmospheric propagation studies at millimeter-wave frequencies.

  6. Voltage, energy and power in electric circuits

    E-print Network

    Haase, Markus

    Voltage, energy and power in electric circuits Science teaching unit #12;Disclaimer The Department-2008DVD-EN Voltage, energy and power in electric circuits #12;#12;© Crown copyright 2008 1The National Strategies | Secondary Voltage, energy and power in electric circuits 00094-2008DVD-EN Contents Voltage

  7. Distributed Energy Management for Electric Power Systems

    E-print Network

    Distributed Energy Management for Electric Power Systems Gabriela Hug, ghug@ece.cmu.edu Soummya Kar Theory Power flow control Consensus + Innovation Approach Theory Energy Management Conclusions 2 #12 Consensus: agreement on price Innovation: power balance Generator Load Storage 9 #12;Energy Dispatch

  8. Ultrasonic power transfer from a spherical acoustic wave source to a free-free piezoelectric receiver: Modeling and experiment

    SciTech Connect

    Shahab, S.; Gray, M.; Erturk, A.

    2015-03-14

    Contactless powering of small electronic components has lately received growing attention for wireless applications in which battery replacement or tethered charging is undesired or simply impossible, and ambient energy harvesting is not a viable solution. As an alternative to well-studied methods of contactless energy transfer, such as the inductive coupling method, the use of ultrasonic waves transmitted and received by piezoelectric devices enables larger power transmission distances, which is critical especially for deep-implanted electronic devices. Moreover, energy transfer by means of acoustic waves is well suited in situations where no electromagnetic fields are allowed. The limited literature of ultrasonic acoustic energy transfer is mainly centered on proof-of-concept experiments demonstrating the feasibility of this method, lacking experimentally validated modeling efforts for the resulting multiphysics problem that couples the source and receiver dynamics with domain acoustics. In this work, we present fully coupled analytical, numerical, and experimental multiphysics investigations for ultrasonic acoustic energy transfer from a spherical wave source to a piezoelectric receiver bar that operates in the 33-mode of piezoelectricity. The fluid-loaded piezoelectric receiver under free-free mechanical boundary conditions is shunted to an electrical load for quantifying the electrical power output for a given acoustic source strength of the transmitter. The analytical acoustic-piezoelectric structure interaction modeling framework is validated experimentally, and the effects of system parameters are reported along with optimal electrical loading and frequency conditions of the receiver.

  9. Mechanochemistry for Shock Wave Energy Dissipation

    NASA Astrophysics Data System (ADS)

    Shaw, William; Ren, Yi; Su, Zhi; Moore, Jeffrey; Suslick, Kenneth; Dlott, Dana

    2015-06-01

    Using our laser-driven flyer-plate apparatus we have developed a technique for detecting mechanically driven chemical reactions that attenuate shock waves. In these experiments 75 ?m laser-driven flyer-plates travel at speeds of up to 2.8 km/s. Photonic Doppler velocimetry is used to monitor both the flight speed and the motions of an embedded mirror behind the sample on the supporting substrate. Since the Hugoniot of the substrate is known, mirror motions can be converted into the transmitted shock wave flux and fluence through a sample. Flux shows the shock profile whereas fluence represents the total energy transferred per unit area, and both are measured as a function of sample thickness. Targets materials are micrograms of carefully engineered organic and inorganic compounds selected for their potential to undergo negative volume, endothermic reactions. In situ fluorescence measurements and a suite of post mortem analytical methods are used to detect molecular chemical reactions that occur due to impact.

  10. Dynamic power balance for nonlinear waves in unbalanced gain and loss landscapes

    E-print Network

    Kominis, Yannis

    2015-01-01

    The presence of losses in nonlinear photonic structures is a crucial issue for modern applications. Active parts are introduced for wave power compensation resulting in unbalanced gain and loss landscapes where localized beam propagation is, in general, dynamically unstable. Here we provide generic sufficient conditions for the relation between the gain-loss and the refractive index profiles in order to ensure efficient wave trapping and stable propagation for a wide range of beam launching conditions such as initial power, angle of incidence and position. The stability is a consequence of an underlying dynamic power balance mechanism related to a conserved quantity of wave dynamics.

  11. Second Proof Work, Power, and Energy

    E-print Network

    Kostic, Milivoje M.

    Second Proof Work, Power, and Energy M. KOSTIC Northern Illinois University DeKalb, Illinois, United States 1. Basic Concepts 2. Forms, Classifications, and Conservation of Energy 3. Work of Conservative and Nonconservative Forces: Work­Energy Principle 4. Energy, Work, and Power of Rotating Systems 5

  12. Careers in Geothermal Energy: Power from below

    ERIC Educational Resources Information Center

    Liming, Drew

    2013-01-01

    In the search for new energy resources, scientists have discovered ways to use the Earth itself as a valuable source of power. Geothermal power plants use the Earth's natural underground heat to provide clean, renewable energy. The geothermal energy industry has expanded rapidly in recent years as interest in renewable energy has grown. In 2011,…

  13. Estimating Energy Dissipation Due to Wave Breaking in the Surf Zone Using Infrared Imagery

    NASA Astrophysics Data System (ADS)

    Carini, Roxanne J.

    Wave breaking is the largest forcing mechanism in the surf zone. Therefore, quantifying energy dissipation due to wave breaking is important for improving models that seek to predict nearshore circulation, wave-current interactions, air-sea gas exchange, erosion and accretion of sediment, and storm surge. Wave energy dissipation is difficult to measure with in situ instruments, and even the most reliable estimates are limited to point measurements. Using remote sensing technologies, specifically infrared (IR) imagery, the high spatial and temporal variability of wave breaking may be sampled. Duncan (1981) proposed a model (D81) for dissipation on a wave-by-wave basis, based on wave slope and roller length, the crest-perpendicular length of the aerated region of a breaking wave. The wave roller is composed of active foam, which, in thermal IR images, appears brighter than the surrounding water and the residual foam, the foam left behind in the wake of a breaking wave. Using IR imagery taken during the Surf Zone Optics 2010 experiment at Duck, NC, and exploiting the distinct signature of active foam, a retrieval algorithm was developed to identify and extract breaking wave roller length. Roller length was then used to estimate dissipation rate via the D81 formulation. The D81 dissipation rate estimates compare reasonably to in situ dissipation estimates at a point. When the D81 estimates are compared to the bulk energy flux into the surf zone, it is found that wave breaking dissipates approximately 25-36% of the incoming wave energy. The D81 dissipation rate estimates also agree closely with those from a dissipation parameterization proposed by Janssen and Battjes (2007) (JB07) and commonly applied within larger nearshore circulation models. The JB07 formulation, however, requires additional physical parameters (wave height and water depth) that are often sparsely sampled and are difficult to attain from remote sensing alone. The power of the D81 formulation lies in its dependence on surface signatures alone, and with the methods developed here and those proposed for future work, wave energy dissipation rate maps could be produced for any imageable coastline.

  14. Modeling of power and energy transduction of embedded piezoelectric wafer active sensors for structural health monitoring

    NASA Astrophysics Data System (ADS)

    Lin, Bin; Giurgiutiu, Victor

    2010-04-01

    This paper presents a systematic investigation of power and energy transduction in piezoelectric wafer active sensors (PWAS) for structural health monitoring (SHM). After a literature review of the state of the art, the paper develops a simplified pitch-catch model of power and energy transduction of PWAS attached to structure. The model assumptions include: (a) 1-D axial and flexural wave propagation; (b) ideal bonding (pin-force) connection between PWAS and structure; (c) ideal excitation source at the transmitter PWAS and fully-resistive external load at the receiver PWAS. Frequency response functions are developed for voltage, current, complex power, active power, etc. First, we examined PWAS transmitter and determined the active power, reactive power, power rating of electrical requirement under harmonic voltage excitation. It was found that the reactive power is dominant and defines the power requirement for power supply / amplifier for PWAS applications. The electrical and mechanical power analysis at the PWAS structure interface indicates all the active electrical power provides the mechanical power at the interface. This provides the power and energy for the axial and flexural waves power and energy that propagate into the structure. The sum of forward and backward wave power equals the mechanical power PWAS applied to the structure. The parametric study of PWAS transmitter size shows the proper size and excitation frequency selection based on the tuning effects. Second, we studied the PWAS receiver structural interface acoustic and electrical energy transduction. The parametric study of receiver size, receiver impedance and external electrical load gives the PWAS design guideline for PWAS sensing and power harvesting applications. Finally we considered the power flow for a complete pitch-catch setup. In pitch-catch mode, the power flows from electrical source into piezoelectric power at the transmitter; the piezoelectric conduction converts the electrical power into the mechanical interface power at the transmitter PWAS and then into the acoustic wave power travelling in the structure. The wave power arrives at the receiver PWAS and is captured at the mechanical interface between the receiver PWAS and the structure; the captured mechanical power is converted back into electrical power at the receiver PWAS and measured by the receiver electrical instrument. Our numerical simulation and graphical chart show the trends in the power and energy flow behavior with remarkable peaks and valleys that can be exploited for optimum design.

  15. Nonlinear damping of high-power magnetostatic waves in yttriumirongarnet films

    E-print Network

    Patton, Carl

    of studies on pulsed and continuous wave cw microwave excitations in ferrite films at high-power levels rate of propagating MSW excitations at high-power levels. Furthermore, recent experimental a detailed and quantitative experimental and theoretical analysis of nonlinear damping for high-power MSW

  16. 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.; Sankaranarayanan, S. K. R. S.

    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.

  17. Integration of ocean thermal energy conversion power plants with existing power systems

    SciTech Connect

    Arunasalam, N.

    1986-01-01

    The problem of integrating an Ocean Thermal Energy Conversion (OTEC) power plant with existing power systems is studied. A nonlinear model of an OTEC power system is developed. The dynamics of the large local induction motor load, and the coaxial cable connection to the mainland are included in the model. The effect of the motor load and the coaxial cable on the steady-state stability of the OTEC power plant is investigated using linearized analysis. The transient stability of the OTEC system is investigated through simulation. The contribution made by the motor load and the coaxial cable to the transient stability is studied. The occurrence of self excitation phenomena is analyzed using linear methods and simulation. The effects of wave and vessel motion on the electrical power output of the OTEC plant is investigated.

  18. 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.

  19. Applications of high power millimeter waves in the DIII-D fusion program

    SciTech Connect

    Freeman, R.L.

    1996-08-01

    First operation of a new generation of MW level, 110 GHz generator (gyrotron) on the DIII-D fusion experimental device has been achieved. The desire for high power, cw millimeter (mm) wave sources to support fusion research and development is just now beginning to be realized. Plasma heating and current drive with directed mm waves rely on the strong absorption achieved when the wave frequency matches the natural ``cyclotron`` frequency of electrons in a magnetic field, or its harmonics. Recent progress in fusion experiments highlights the need for control of the interior details of the hot plasma, and nun wave systems are ideally suited for this role. A brief status of fusion research is given, and the importance of mm waves in the future directions for fusion research is described. The vacuum transmission components necessary for transmitting, monitoring, and launching high power 1 10 GHz waves into a plasma have been developed at General Atomics (GA) and will be described. High power mm waves have a number of attractive technological features for fusion applications compared with other candidate plasma heating and current drive technologies. Millimeter waves can be transmitted with high power density over large distances with low losses by utilizing corrugated waveguides, so the generators can be sited remotely, facilitating maintenance and saving valuable space near the fusion device.

  20. Dark energy from quantum wave function collapse of dark matter

    E-print Network

    A. S. Majumdar; D. Home; S. Sinha

    2009-09-03

    Dynamical wave function collapse models entail the continuous liberation of a specified rate of energy arising from the interaction of a fluctuating scalar field with the matter wave function. We consider the wave function collapse process for the constituents of dark matter in our universe. Beginning from a particular early era of the universe chosen from physical considerations, the rate of the associated energy liberation is integrated to yield the requisite magnitude of dark energy around the era of galaxy formation. Further, the equation of state for the liberated energy approaches $w \\to -1$ asymptotically, providing a mechanism to generate the present acceleration of the universe.

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

    SciTech Connect

    Singh, Rohtash; Sharma, A. K.; Tripathi, V. K.

    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.

  2. 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.

  3. 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.

  4. Analysis and simulation of standing wave pattern of powerful HF radio waves in ionospheric reflection region

    NASA Astrophysics Data System (ADS)

    Wang, Chen; Zhou, Chen; Zhao, Zheng-Yu; Yang, Xu-Bo

    2015-12-01

    For the study of the various non-linear effects generated in ionospheric modulation experiments, accurate calculation of the field intensity variation in the whole reflection region for an electromagnetic wave vertically impinging upon the ionosphere is meaningful. In this paper, mathematical expressions of the electric field components of the characteristic heating waves are derived, by coupling the equation describing a wave initially impinging vertically upon the ionosphere with the Forsterling equation. The variation of each component of the electric field and the total electric field intensity of the standing wave pattern under a specific density profile are calculated by means of a uniform approximation, which is applied throughout the region near the reflection point. The numerical calculation results demonstrate that the total electric field intensity of the ordinary (O)-mode wave varies rapidly in space and reaches several maxima below the reflection point. Evident swelling phenomena of the electric field intensity are found. Our results also indicate that this effect is more pronounced at higher latitudes and that the geomagnetic field is important for wave pattern variation. The electric field intensity of the standing wave pattern of the extraordinary (X)-mode wave exhibits some growth below the reflection point, but its swelling effect is significantly weaker than that of the O-mode wave.

  5. High Average Power, High Energy Short Pulse Fiber Laser System

    SciTech Connect

    Messerly, M J

    2007-11-13

    Recently continuous wave fiber laser systems with output powers in excess of 500W with good beam quality have been demonstrated [1]. High energy, ultrafast, chirped pulsed fiber laser systems have achieved record output energies of 1mJ [2]. However, these high-energy systems have not been scaled beyond a few watts of average output power. Fiber laser systems are attractive for many applications because they offer the promise of high efficiency, compact, robust systems that are turn key. Applications such as cutting, drilling and materials processing, front end systems for high energy pulsed lasers (such as petawatts) and laser based sources of high spatial coherence, high flux x-rays all require high energy short pulses and two of the three of these applications also require high average power. The challenge in creating a high energy chirped pulse fiber laser system is to find a way to scale the output energy while avoiding nonlinear effects and maintaining good beam quality in the amplifier fiber. To this end, our 3-year LDRD program sought to demonstrate a high energy, high average power fiber laser system. This work included exploring designs of large mode area optical fiber amplifiers for high energy systems as well as understanding the issues associated chirped pulse amplification in optical fiber amplifier systems.

  6. Newly Discovered Parametric Instabilities Excited by High Power Radio Waves in the Ionosphere

    NASA Astrophysics Data System (ADS)

    Bernhardt, Paul

    2010-11-01

    A powerful electromagnetic wave can decay into a large number of low frequency electrostatic waves and a scattered electromagnetic wave by generalized stimulated Brillouin scatter (GSBS). The generalization occurs in the F-layer ionosphere because of the presence of the magnetic field supporting a large number of plasma waves not present in an unmagnetized plasma. Stimulated Brillouin scatter excites the ion acoustic mode. In addition, GSBS can excite slow MHD, Alfven, fast MHD, ion cyclotron, whistler, lower hybrid, ion Bernstein waves. The first detection of this process during ionospheric modification with high power radio waves was demonstrated using the HAARP transmitter in Alaska in 2009. Subsequent experiments have provided additional verification of the GSBS process with quantitative measurements of the scattered electromagnetic waves with low frequency offsets from the pump wave. Relative to ground-based laboratory experiments with laser plasma interactions, the ionospheric HF wave interactions experiments are more completely diagnosed into terms of understanding the basic decay process of the magnetized plasma. Applications of the GSBS observations included remote sensing of the plasma state and launching propagating wave modes.

  7. 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 ...

  8. Jason Tracks Powerful Tropical Cyclone Gonu's High Winds, Waves

    NASA Technical Reports Server (NTRS)

    2007-01-01

    [figure removed for brevity, see original site] [figure removed for brevity, see original site] Wind Speed Wave Height Click on images for larger versions

    This pair of images from the radar altimeter instrument on the U.S./France Jason mission reveals information on wind speeds and wave heights of Tropical Cyclone Gonu, which reached Category 5 strength in the Arabian Sea prior to landfall in early June 2007. Strong winds near 20 meters per second and wave heights of greater than 5 meters were recorded. These high waves are extremely rare in the Arabian Sea and exacerbated heavy flooding from the storm surge over much of the Oman coastline.

    The U.S. portion of the Jason mission is managed by JPL for NASA's Science Mission Directorate, Washington, D.C. Research on Earth's oceans using Jason and other space-based capabilities is conducted by NASA's Science Mission Directorate to better understand and protect our home planet.

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

    SciTech Connect

    Efimov, V. B.; Ganshin, A. N.; McClintock, P. V. E.; Kolmakov, G. V.; Mezhov-Deglin, L. P.

    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.

  10. 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.

  11. 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.

  12. 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.

  13. Combined Thermal and Power Energy Management Optimization 

    E-print Network

    Ahner, D. J.; Priestley, R. R.

    1991-01-01

    . In contrast to the conventional utility power plant optimization, the algorithm for cogeneration plants is much more complex. The incremental relationships for a utility power plant may be expressed by a single plant fuel input versus power output... characteristic. However, cogeneration applications often require the consideration of multiple energy sources, individual plant equipment incremental performance, the simultaneous demands for power and process heat at various energy levels and complex...

  14. ENERGY CONTENT AND PROPAGATION IN TRANSVERSE SOLAR ATMOSPHERIC WAVES

    SciTech Connect

    Goossens, M.; Van Doorsselaere, T.; Soler, R.; Verth, G.

    2013-05-10

    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 paper, the kinetic, magnetic, and total energy densities and the flux of energy are computed for transverse MHD waves in one-dimensional cylindrical flux tube models with a piecewise constant or continuous radial 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 has the important consequence that the energy flux computed with the well known expression for bulk Alfven waves could overestimate the real flux by a factor in the range 10-50, depending on the flux tube equilibrium properties.

  15. Fusion EnergyFusion Energy Powering the XXI centuryPowering the XXI century

    E-print Network

    Fusion EnergyFusion Energy Powering the XXI centuryPowering the XXI century Carlos Matos FerreiraInstituto SuperiorSuperior TTéécnicocnico,, LisboaLisboa, Portugal, Portugal 20th International Atomic Energy Agency, Fusion Energy Conference, Vilamoura, Portugal #12;OutlineOutline ·· World Energy ConsumptionWorld Energy

  16. Preliminary Analysis of an Oscillating Surge Wave Energy Converter with Controlled Geometry: Preprint

    SciTech Connect

    Tom, Nathan; Lawson, Michael; Yu, Yi-Hsiang; Wright, Alan

    2015-09-09

    The aim of this paper is to present a novel wave energy converter device concept that is being developed at the National Renewable Energy Laboratory. The proposed concept combines an oscillating surge wave energy converter with active control surfaces. These active control surfaces allow for the device geometry to be altered, which leads to changes in the hydrodynamic properties. The device geometry will be controlled on a sea state time scale and combined with wave-to-wave power-take-off control to maximize power capture, increase capacity factor, and reduce design loads. The paper begins with a traditional linear frequency domain analysis of the device performance. Performance sensitivity to foil pitch angle, the number of activated foils, and foil cross section geometry is presented to illustrate the current design decisions; however, it is understood from previous studies that modeling of current oscillating wave energy converter designs requires the consideration of nonlinear hydrodynamics and viscous drag forces. In response, a nonlinear model is presented that highlights the shortcomings of the linear frequency domain analysis and increases the precision in predicted performance.

  17. Measurement of acoustic output power in a traveling wave engine.

    PubMed

    Miwa, M; Sumi, T; Biwa, T; Ueda, Y; Yazaki, T

    2006-12-22

    We built and tested a double-loop thermoacoustic cooler consisting of an engine-loop, a branch resonator, and a cooler-loop. The cooling power of 6.4 W was obtained at the cooling temperature of 0 degrees C, when the input heat power of 416 W was supplied to the engine-loop. We measured the acoustic power and found that the output power emitted from the engine-loop was 12 W, and that the input acoustic power entering the cooler-loop was 6 W. PMID:16996552

  18. Time- and power-dependent operation of a parametric spin-wave amplifier

    SciTech Connect

    Brächer, T.; Heussner, F.; Pirro, P.; Fischer, T.; Geilen, M.; Heinz, B.; Lägel, B.; Serga, A. A.; Hillebrands, B.

    2014-12-08

    We present the experimental observation of the localized amplification of externally excited, propagating spin waves in a transversely in-plane magnetized Ni{sub 81}Fe{sub 19} magnonic waveguide by means of parallel pumping. By employing microfocussed Brillouin light scattering spectroscopy, we analyze the dependency of the amplification on the applied pumping power and on the delay between the input spin-wave packet and the pumping pulse. We show that there are two different operation regimes: At large pumping powers, the spin-wave packet needs to enter the amplifier before the pumping is switched on in order to be amplified while at low powers the spin-wave packet can arrive at any time during the pumping pulse.

  19. Variability of ULF wave power at the magnetopause: a study at low latitude with Cluster data

    NASA Astrophysics Data System (ADS)

    Cornilleau-Wehrlin, N.; Grison, B.; Belmont, G.; Rezeau, L.; Chanteur, G.; Robert, P.; Canu, P.

    2012-04-01

    Strong ULF wave activity has been observed at magnetopause crossings since a long time. Those turbulent-like waves are possible contributors to particle penetration from the Solar Wind to the Magnetosphere through the magnetopause. Statistical studies have been performed to understand under which conditions the ULF wave power is the most intense and thus the waves can be the most efficient for particle transport from one region to the other. Clearly the solar wind pressure organizes the data, the stronger the pressure, the higher the ULF power (Attié et al 2008). Double STAR-Cluster comparison has shown that ULF wave power is stronger at low latitude than at high latitude (Cornilleau-Wehrlin et al, 2008). The different studies performed have not, up to now, shown a stronger power in the vicinity of local noon. Nevertheless under identical activity conditions, the variability of this power, even at a given location in latitude and local time is very high. The present work intends at understanding this variability by means of the multi spacecraft mission Cluster. The data used are from spring 2008, while Cluster was crossing the magnetopause at low latitude, in particularly quite Solar Wind conditions. The first region of interest of this study is the sub-solar point vicinity where the long wavelength surface wave effects are most unlikely.

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

    E-print Network

    , prototype, demonstration, or initial commercial application. The session covered technology suppliers. Pulse uses an oscillating hydrofoil for energy capture: horizontal wing-shaped blades move up and down technology (OTEC) to provide commercial power and is developing the first commercial land-based application

  1. Continuous-wave 193.4??nm laser with 120??mW output power.

    PubMed

    Sakuma, Jun; Kaneda, Yushi; Oka, Naoya; Ishida, Takayuki; Moriizumi, Koichi; Kusunose, Haruhiko; Furukawa, Yasunori

    2015-12-01

    This Letter describes an all-solid-state continuous-wave, deep-ultraviolet coherent source that generates more than 100 mW of output power at 193.4 nm. The source is based on nonlinear frequency conversion of three single-frequency infrared fiber laser master-oscillator power-amplifier (MOPA) light sources. PMID:26625058

  2. Water Power for a Clean Energy Future

    SciTech Connect

    2013-04-12

    This document describes some of the accomplishments of the Department of Energy Water Power Program, and how those accomplishments are supporting the advancement of renewable energy generated using hydropower technologies and marine and hydrokinetic technologies.

  3. Renewable Energy Powered Water Treatment Systems 

    E-print Network

    Richards, Bryce S.; Schäfer, Andrea

    2009-01-01

    There are many motivations for choosing renewable energy technologies to provide the necessary energy to power water treatment systems for reuse and desalination. These range from the lack of an existing electricity grid, ...

  4. Optimizing Ballast Design of Wave Energy Converters Using Evolutionary Algorithms

    E-print Network

    Tumer, Kagan

    University Corvallis, OR, 97331 nasroumo@engr.orst.edu Kagan Tumer Oregon State University Corvallis, OR, 97331 kagan.tumer@oregonstate.edu ABSTRACT Wave energy converters promise to be a viable alternative

  5. 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 ...

  6. Internal wave energy radiated from a turbulent mixed layer

    SciTech Connect

    Munroe, James R.; Sutherland, Bruce R.

    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.

  7. 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

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

    SciTech Connect

    Kuo, Spencer; Snyder, Arnold; Chang, Chia-Lie

    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.

  9. Effects of nonlinear energy transfer on short surface waves

    NASA Astrophysics Data System (ADS)

    Lyzenga, David R.

    2010-10-01

    The effects of nonlinear energy transfer on the development of the short wave spectrum are evaluated using a diffusion approximation and a modification of this approximation to include nonlocal effects. Both formulations were used to compute the evolution of a JONSWAP-type spectrum, and the results are compared with direct numerical simulations. Terms corresponding to each of these formulations were then incorporated into the wave action equation, and the resulting equation was numerically integrated using a second-order Runge-Kutta method. The results show an increase in the angular width of the spectrum and in the spectral density at high wave numbers as compared with solutions of the action equation without the nonlinear energy transfer term. Example results are presented for the case of a moderately strong internal wave in a light wind, and implications for the remote sensing of these waves using microwave radar are discussed.

  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. 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

  12. 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 2, Czech Republic. E­mail vcerveny@seis.karlov.m#.cuni.cz Summary The energy flux of time to consider the average energy flux, which is real­valued and time­independent. An extension

  13. 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 ...

  14. Solar energy thermally powered electrical generating system

    NASA Technical Reports Server (NTRS)

    Owens, William R. (Inventor)

    1989-01-01

    A thermally powered electrical generating system for use in a space vehicle is disclosed. The rate of storage in a thermal energy storage medium is controlled by varying the rate of generation and dissipation of electrical energy in a thermally powered electrical generating system which is powered from heat stored in the thermal energy storage medium without exceeding a maximum quantity of heat. A control system (10) varies the rate at which electrical energy is generated by the electrical generating system and the rate at which electrical energy is consumed by a variable parasitic electrical load to cause storage of an amount of thermal energy in the thermal energy storage system at the end of a period of insolation which is sufficient to satisfy the scheduled demand for electrical power to be generated during the next period of eclipse. The control system is based upon Kalman filter theory.

  15. Observation and theory of whistler wave generation by high-power HF waves

    NASA Astrophysics Data System (ADS)

    Kuo, Spencer; Cheng, Wei-Te; Pradipta, R.; Lee, M. C.; Snyder, Arnold

    2013-03-01

    Summer midnight and afternoon VLF wave generation comparison experiments were conducted on 25 July and 27 July 2011, respectively, using two CW HF X-mode waves with 11 VLF frequency differences from 2 to 21.5 kHz. The background magnetic variations were at comparable levels. During the afternoon experiment, the D region absorption was significant and increasing. The number of the ionogram echoes decreased during the afternoon experiment. VLF signals were detected from 2 to 7.6 kHz in both experiments, showing an inverse frequency dependence of intensity, although signal intensity (except at 5.5 kHz) detected during the midnight experiment was stronger than the corresponding afternoon intensity before observing a decrease of the number of ionogram echoes. However, VLF signals from 11.5 to 21.5 (except at 19.6 kHz) were also generated in the afternoon experiment concurrent with a decrease of the O-mode ionosonde echoes from 2 to 4 MHz. The concurrence of a decrease of the afternoon ionogram echoes, the unexpected generation of VLF waves at higher frequencies, and the increasing D region absorption throughout the experiment may be explained by the generation of large-scale density irregularities, which scatter the ionosonde signals as well as couple with the modulated electrojet to generate whistler waves. A theoretical formulation of the coupling mechanism for the whistler wave generation is presented.

  16. 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.

  17. Renewable Energy. The Power to Choose.

    ERIC Educational Resources Information Center

    Deudney, Daniel; Flavin, Christopher

    This book, consisting of 13 chapters, charts the progress made in renewable energy in recent years and outlines renewable energy's prospects. Areas addressed include: energy at the crossroads (discussing oil, gas, coal, nuclear power, and the conservation revolution); solar building design; solar collection; sunlight to electricity; wood; energy…

  18. 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.

  19. HIGH POWER OPERATIONS AT THE LOW ENERGY DEMONSTRATION ACCELERATOR (LEDA)

    SciTech Connect

    M. DURAN; V. R. HARRIS

    2001-01-01

    Recently, the Low-Energy Demonstration Accelerator (LEDA) portion of the Accelerator Production of Tritium (APT) project reached its 100-mA, 8-hr continuous wave (CW) beam operation milestone. The LEDA accelerator is a prototype of the low-energy front-end of the linear accelerator (linac) that would have been used in an APT plant. LEDA consists of a 75-keV proton injector, 6.7-MeV, 350-MHz CW radio-frequency quadrupole (RFQ) with associated high-power and low-level RF systems, a short high-energy beam transport (HEBT) and high-power (670-kW CW) beam dump. Details of the LEDA design features will be discussed along with the operational health physics experiences that occurred during the LEDA commissioning phase.

  20. An array effect of wave energy farm buoys

    NASA Astrophysics Data System (ADS)

    Kweon, Hyuck-Min; Lee, Jung-Lyul

    2012-12-01

    An ocean buoy energy farm is considered for Green energy generation and delivery to small towns along the Korean coast. The present studypresents that the floating buoy-type energy farm appears to be sufficiently feasible fortrapping more energy compared to afixed cylinder duck array. It is also seen from the numerical resultsthat the resonated waves between spaced buoys are further trapped by floating buoy motion.Our numerical study is analyzed by a plane-wave approximation, in which evanescent mode effects are included in a modified mild-slope equation based on the scattering characteristics for a single buoy.

  1. 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.

  2. Traveling-wave photomixers fabricated on high energy nitrogen-ion-implanted GaAs

    SciTech Connect

    Mikulics, M.; Michael, E. A.; Marso, M.; Lepsa, M.; Hart, A. van der; Lueth, H.; Dewald, A.; Stancek, S.; Mozolik, M.; Kordos, P.

    2006-08-14

    The authors report on fabrication and measurement of traveling-wave photomixers based on high energy and low dose nitrogen-ion-implanted GaAs. They used 3 MeV energy to implant N{sup +} ions into GaAs substrates with an ion concentration dose of 3x10{sup 12} cm{sup -2}. The N{sup +}-implanted GaAs photomixers exhibit improvements in the output power in comparison with their counterparts, photomixers fabricated on low-temperature-grown GaAs. The maximal output power was 2.64 {mu}W at 850 GHz. No saturation of the output power with increased bias voltage and optical input power was observed. These characteristics make N{sup +}-implanted GaAs the material of choice for efficient high power sources of terahertz radiation.

  3. Fractal ladder models and power law wave equations.

    PubMed

    Kelly, James F; McGough, Robert J

    2009-10-01

    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

  4. 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

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

    NASA Technical Reports Server (NTRS)

    Dayton, James A., 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 TWT dimensions scale approximately with wavelength, mm wave devices will be physically much smaller with inherently more stringent fabrication tolerances and sensitivity to thermal dissipation.

  6. High power laser and explosive driven shock wave characterization in solids using fiber optic probes

    NASA Astrophysics Data System (ADS)

    Cranch, G. A.; Grün, J.; Weaver, J.; Gran, J. K.; Groethe, M. A.; Compton, S.; Fournier, K.; Dunlop, B.

    2015-09-01

    Shock wave transmission and propagation in solid media is studied using fiber optic pressure and velocity probes. Shock waves are generated in two experiments using a high power laser facility as well as conventional explosives. Shock wave properties including peak overpressure, mass velocity, shock duration, impulse, arrival time and shock velocity are characterized using fiber tip interferometric displacement sensors and Fabry-Perot pressure sensors. Measurements are conducted in polymethyl methacrylate and limestone. The probes recorded shock pressures up to 0.1 GPa (1 kbar). Measurements from the fiber optic sensors are shown to be in close agreement with measurements from an electrical sensor based on a Dremin loop.

  7. 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.

  8. First On-Wafer Power Characterization of MMIC Amplifiers at Sub-Millimeter Wave Frequencies

    NASA Technical Reports Server (NTRS)

    Fung, A. K.; Gaier, T.; Samoska, L.; Deal, W. R.; Radisic, V.; Mei, X. B.; Yoshida, W.; Liu, P. S.; Uyeda, J.; Barsky, M.; Lai, R.

    2008-01-01

    Recent developments in semiconductor technology have enabled advanced submillimeter wave (300 GHz) transistors and circuits. These new high speed components have required new test methods to be developed for characterizing performance, and to provide data for device modeling to improve designs. Current efforts in progressing high frequency testing have resulted in on-wafer-parameter measurements up to approximately 340 GHz and swept frequency vector network analyzer waveguide measurements to 508 GHz. On-wafer noise figure measurements in the 270-340 GHz band have been demonstrated. In this letter we report on on-wafer power measurements at 330 GHz of a three stage amplifier that resulted in a maximum measured output power of 1.78mW and maximum gain of 7.1 dB. The method utilized demonstrates the extension of traditional power measurement techniques to submillimeter wave frequencies, and is suitable for automated testing without packaging for production screening of submillimeter wave circuits.

  9. The impact of sea surface currents in wave power potential modeling

    NASA Astrophysics Data System (ADS)

    Zodiatis, George; Galanis, George; Kallos, George; Nikolaidis, Andreas; Kalogeri, Christina; Liakatas, Aristotelis; Stylianou, Stavros

    2015-11-01

    The impact of sea surface currents to the estimation and modeling of wave energy potential over an area of increased economic interest, the Eastern Mediterranean Sea, is investigated in this work. High-resolution atmospheric, wave, and circulation models, the latter downscaled from the regional Mediterranean Forecasting System (MFS) of the Copernicus marine service (former MyOcean regional MFS system), are utilized towards this goal. The modeled data are analyzed by means of a variety of statistical tools measuring the potential changes not only in the main wave characteristics, but also in the general distribution of the wave energy and the wave parameters that mainly affect it, when using sea surface currents as a forcing to the wave models. The obtained results prove that the impact of the sea surface currents is quite significant in wave energy-related modeling, as well as temporally and spatially dependent. These facts are revealing the necessity of the utilization of the sea surface currents characteristics in renewable energy studies in conjunction with their meteo-ocean forecasting counterparts.

  10. Gravitational Waves and high energy phenomena

    NASA Astrophysics Data System (ADS)

    Leroy, N.; Clapson, A.-C.

    2005-12-01

    In the coming years several instruments dedicated to gravitational wave detection will be operational at their design sensitivity. Analysis combining all these detectors will improve sky coverage and provide source location indications. We focus on plausible astrophysical gravitational wave sources and the information that could be extracted from an observation. We can expect exclusive details on compact objects, from constraints on the equation of state to core dynamics. Multi-messenger data on the same event would allow for rich analysis, already considered for supernovae, but to be investigated further, including for other phenomena.

  11. Estimates of the power per mode number of broadband ULF waves at geosynchronous orbit

    NASA Astrophysics Data System (ADS)

    Sarris, T. E.

    2014-07-01

    In studies of radial diffusion processes in the magnetosphere it is well known that ultralow frequency (ULF) waves of frequency m?d can resonantly interact with particles of drift frequency ?d, where m is the waves' azimuthal mode number. Due to difficulties in estimating m, an oversimplifying assumption is often made in simulations, namely that all ULF wave power is located at a single mode number. In this paper a technique is presented for extracting information on the distribution of ULF power in a range of azimuthal mode numbers. As a first step, the cross power and phase differences between time series from azimuthally aligned magnetometers are calculated. Subsequently, through integrating the ULF power at particular ranges of phase differences that correspond to particular mode numbers, estimates of the fraction of the total power at each phase difference range or mode number are provided. Albeit entwined with many ambiguities, this technique offers critical information that is currently missing when estimating radial diffusion of energetic particles. As proof-of-concept, the technique is first tested successfully for a well-studied case of narrowband ULF Field Line Resonances (FLR) for which the mode number was calculated simultaneously through ground-based and space measurements. Subsequently, the technique is demonstrated for the broadband ULF waves that accompanied the 2003 "Halloween" magnetospheric storms. The temporal evolution of power at each mode number gives insight into the evolution of ULF waves during a storm as well as more accurate characterization of broadband ULF waves that can be used in radial diffusion simulations.

  12. 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.

  13. 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.

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

    SciTech Connect

    Ian Balitsky

    2005-06-16

    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.

  15. Importance of electron cyclotron wave energy transport in ITER

    NASA Astrophysics Data System (ADS)

    Albajar, F.; Bornatici, M.; Cortes, G.; Dies, J.; Engelmann, F.; Garcia, J.; Izquierdo, J.

    2005-07-01

    The importance of electron cyclotron (EC) wave emission to the local electron power balance is analysed for various ITER operation regimes and, for comparison, for typical working conditions of FIRE, IGNITOR and the reactor-grade ITER concept as considered during the Engineering Design Phase (ITER-EDA). To cover the non-local effects in EC wave emission as well, the CYTRAN routine along with the ASTRA transport code is used. As a result, EC wave emission is shown to be a significant contributor to core electron cooling if the core electron temperature is about 35 keV or higher, as expected for ITER and tokamak reactor steady-state operation; in fact, it becomes the dominant core electron cooling mechanism at temperatures exceeding 40 keV, as such affecting the core plasma power balance in an important way.

  16. 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.

  17. Laser Fusion Energy The High Average Power

    E-print Network

    Laser Fusion Energy and The High Average Power Program John Sethian Naval Research Laboratory Dec for Inertial Fusion Energy with lasers, direct drive targets and solid wall chambers Lasers DPPSL (LLNL) Kr posters Snead Payne #12;Laser(s) Goals 1. Develop technologies that can meet the fusion energy

  18. Energy savings in industrial electric power plants

    SciTech Connect

    Ishikawa, M.; Yamazaki, S.

    1981-07-01

    To make further progress in energy savings at factories, new technologies involving the utilization of low temperature waste heat or the introduction of new total energy systems to improve heat utilization over a wide range will be needed. This paper presents such methods for promoting energy savings at industrial electric power plants.

  19. 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.

  20. Teachers Environmental Resource Unit: Energy and Power.

    ERIC Educational Resources Information Center

    Bemiss, Clair W.

    Problems associated with energy production and power are studied in this teacher's guide to better understand the impact of man's energy production on the environment, how he consumes energy, and in what quantities. The resource unit is intended to provide the teacher with basic information that will aid classroom review of these problems. Topics…

  1. 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.

  2. 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.

  3. Feasibility of Traveling Wave Direct Energy Conversion of Fission Reaction Fragments

    NASA Technical Reports Server (NTRS)

    Tarditi, A. G.; George, J. A.; Miley, G. H.; Scott, J. H.

    2013-01-01

    Fission fragment direct energy conversion has been considered in the past for the purpose of increasing nuclear power plant efficiency and for advanced space propulsion. Since the fragments carry electric charge (typically in the order of 20 e) and have 100 MeV-range kinetic energy, techniques utilizing very high-voltage DC electrodes have been considered. This study is focused on a different approach: the kinetic energy of the charged fission fragments is converted into alternating current by means of a traveling wave coupling scheme (Traveling Wave Direct Energy Converter, TWDEC), thereby not requiring the utilization of high voltage technology. A preliminary feasibility analysis of the concept is introduced based on a conceptual level study and on a particle simulation model of the beam dynamics.

  4. Energy flux of edge waves travelling along a continental shelf

    NASA Astrophysics Data System (ADS)

    Shillington, F. A.; Brundrit, G. B.

    Longuet-Higgins (1964) originally recognised that the energy flux defined by pressure work from the equations of motion was not the same as the mean energy density times the group velocity for planetary waves on a beta-plane. This paper addresses a similar paradox for linear, long period edge waves on an arbitrary shaped (in the offshore direction) straight continental shelf. The approach is to first examine a wavetrain solution to the problem and then to use a multiple scale argument which results in a solution as a group of waves modulated about a central frequency and wavenumber k. The paradox is resolved in both instances by noting that a divergence free quantity J can be included in the energy conservation equation to establish an equivalence between the two definitions of mean energy flux. For the wavetrain solution where x is the offshore direction, h(x) is the depth, A(k,x) is the complex wave displacement, is the frequency and k is the wavenumber. For the modulated group, the quantity J is given by ? where B=B(Y, T) is part of the edge wave complex amplitude A(k, x)B(Y, T) and Y, T are the long longshore and time variables respectively. We discuss which energy flux definition is preferable in a given situation.

  5. On The Implications of Atmospheric Gravity Waves on Wind Power 

    E-print Network

    Norris, Luke

    2011-11-24

    In view of the rapidly rising cost of fossil fuels and concerns over climate change, there can be little doubt that renewable energy is to play a large role in the future of our economic development. The impact of Atmospheric ...

  6. 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.

  7. 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.

  8. Power and Energy Engineering Workforce Collaborative

    E-print Network

    challenges 3.Make the world a better place to live · Energy and Power Engineering is... ­ Exciting ­ Critical ­ Registrations: 325 students from about 80 institutions, 100 employers (engineering services, manufacturing

  9. Parameterization of Observed Saturn Z-Mode Wave Power for r < 4Rs

    NASA Astrophysics Data System (ADS)

    Menietti, J. D.; Ye, S.; Averkamp, T. F.; Horne, R. B.; Shprits, Y.; Woodfield, E. E.; Gurnett, D. A.

    2014-12-01

    Recent work has shown that z-mode/electron wave-particle interactions can lead to electron acceleration in the Saturn magnetosphere. These electrons may then form a partial source of Saturn's radiation belt which peaks in the range ~2Rs < r ~4Rs. The wave acceleration process depends on the local plasma density and on the distribution of z-mode wave power in frequency and spatial coordinates. In this study we bin the z-mode wave power observed by the Cassini radio and plasma wave science (RPWS) investigation in the region r < 4Rs at Saturn, where the condition fp/fc < 1 can be met (fp = plasma freq., fc = cyclotron freq.). The spatial bins include L-shell (based on a magnetic field model), latitude, and local time. Within each spatial bin we calculate the mean power-versus-frequency profile relative to fc, which can then be analytically fit. One goal of the study is to provide a database for use in quasilinear models requiring the calculation of pitch angle and momentum diffusion coefficients. In this report we present our initial findings.

  10. High-power TM01 millimeter wave pulse sensor in circular waveguide

    NASA Astrophysics Data System (ADS)

    Wang, Guang-Qiang; Zhu, Xiang-Qin; Chen, Zai-Gao; Wang, Xue-Feng; Zhang, Li-Jun

    2015-09-01

    By investigating the interaction of an n-type silicon sample with the TM01 mode millimeter wave in a circular waveguide, a viable high-power TM01 millimeter wave sensor is proposed. Based on the hot electron effect, the silicon sample serving as a sensing element (SE) and appropriately mounted on the inner wall of the circular waveguide is devoted to the on-line measurement of a high-power millimeter wave pulse. A three-dimensional parallel finite-difference time-domain method is applied to simulate the wave propagation within the measuring structure. The transverse electric field distribution, the dependences of the frequency response of the voltage standing-wave ratio (VSWR) in the circular waveguide, and the average electric field amplitude within the SE on the electrophysical parameters of the SE are calculated and analyzed in the frequency range of 300-400 GHz. As a result, the optimal dimensions and specific resistance of the SE are obtained, which provide a VSWR of no more than 2.0, a relative sensitivity around 0.0046 kW-1 fluctuating within ± 17.3%, and a maximum enduring power of about 4.3 MW. Project supported by the National Natural Science Foundation of China (Grant No. 61231003).

  11. Power Technologies Energy Data Book - Fourth Edition

    SciTech Connect

    Aabakken, J.

    2006-08-01

    This report, prepared by NREL's Strategic Energy Analysis Center, includes up-to-date information on power technologies, including complete technology profiles. The data book also contains charts on electricity restructuring, power technology forecasts, electricity supply, electricity capability, electricity generation, electricity demand, prices, economic indicators, environmental indicators, and conversion factors.

  12. Energy Decisions: Is Solar Power the Solution?

    ERIC Educational Resources Information Center

    Childress, Vincent W.

    2011-01-01

    People around the world are concerned about affordable energy. It is needed to power the global economy. Petroleum-based transportation and coal-fired power plants are economic prime movers fueling the global economy, but coal and gasoline are also the leading sources of air pollution. Both of these sources produce greenhouse gases and toxins.…

  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. 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%.

  15. Study Pelamis system to capture energy of ocean wave

    E-print Network

    Gobato, Ricardo; Fedrigo, Desire Francine Gobato

    2015-01-01

    Over the years, energy has become vital for humans, enabling us to comfort, leisure, mobility and other factors. The quest for cheap energy sources, renewable and clean has grown in recent years, mainly for the reduction of effects that comes degrading nature, allowing scientists and engineers to search for new technologies. Many energy sources have been researched for proper funding where some stand out for their ease of obtaining, by other low cost and others by being renewable. The main objective of this work is to study one of these energy sources - wave energy, whose capture is still in development. This energy comes from the waves of the sea and is 100% renewable and with minimal environmental impact when compared to hydro, nuclear, coal, thermal, etc. The system studied here is the Pelamis system.

  16. 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.

  17. X-Ray Vision with Only WiFi Power Measurements Using Rytov Wave Models

    E-print Network

    1 X-Ray Vision with Only WiFi Power Measurements Using Rytov Wave Models Saandeep Depatla, Lucas the surface of the earth is one example [17]. Traditional medical imaging based on X-ray also falls, such as Simultaneous Localization and Mapping (SLAM), has been developed for mapping based on laser scanner

  18. Millimeter wave tokamak heating and current drive with a high power free electron laser

    SciTech Connect

    Thomassen, K.I.

    1987-01-01

    Experiments on microwave generation using a free electron laser (FEL) have shown this to be an efficient way to generate millimeter wave power in short, intense pulses. Short pulse FEL's have several advantages that make them attractive for application to ECR heating of tokamak fusion reactors. This paper reports on plans made to demonstrate the technology at the Microwave Tokamak Experiment (MTX) Facility.

  19. Proc 12th conf. RF Power in Plasmas, Savannah, 1997 Ion-Bernstein Wave Mode Conversion

    E-print Network

    Jaun, André

    Proc 12th conf. RF Power in Plasmas, Savannah, 1997 Ion-Bernstein Wave Mode Conversion in Hot conversion at the second harmonic cyclotron resonance is studied in a toroidal plasma, showing how the ion branch may however be transferred to the other in a process called linear mode conversion. It generally

  20. Electromagnetic Wave Power Observed Near the Moon during Terrestrial Bow Shock Crossings

    E-print Network

    Fillingim, Matthew

    provide MT source signals. On airless bodies such as the Moon, solar wind turbulence, shocks, and plasmaElectromagnetic Wave Power Observed Near the Moon during Terrestrial Bow Shock Crossings and Its-band whistlers ~ 1 Hz in the solar wind measurements of the horizontal electric and magnetic fields are used

  1. Dynamic breakwater and wave energy recovery and conversion system

    SciTech Connect

    Boros, L.J.

    1983-05-24

    A dynamic breakwater system includes at least one and preferably a plurality of dynamic breakwater assemblies, each of which includes a baffle wall member which is pivotally mounted in a body of water about an axis which extends substantially transverse to the direction of wave motion and so that a lower portion thereof is submerged below the water surface while an upper portion thereof extends above the water surface, each baffle wall member being biased such that it has a tendency to move in a direction opposite to the direction of wave motion and wherein apparatus for damping the movement of the baffle wall member when the same moves in the direction of wave motion under the force of waves impinging thereon are provided. Apparatus is provided for recovering at least a portion of the energy imparted to the baffle wall member by the waves impinging thereon and for converting the same to useful energy and generally comprises a fluid circuit supported on a stationary platform assembly and a device operatively interconnecting the baffle wall member and fluid circuit for elevating the pressure of the fluid circulating therein in response to movement of the baffle wall member caused by the waves impinging thereon.

  2. Coal and nuclear power: Illinois' energy future

    SciTech Connect

    Not Available

    1982-01-01

    This conference was sponsored by the Energy Resources Center, University of Illinois at Chicago; the US Department of Energy; the Illinois Energy Resources Commission; and the Illinois Department of Energy and Natural Resources. The theme for the conference, Coal and Nuclear Power: Illinois' Energy Future, was based on two major observations: (1) Illinois has the largest reserves of bituminous coal of any state and is surpassed in total reserves only by North Dakota, and Montana; and (2) Illinois has made a heavy commitment to the use of nuclear power as a source of electrical power generation. Currently, nuclear power represents 30% of the electrical energy produced in the State. The primary objective of the 1982 conference was to review these two energy sources in view of the current energy policy of the Reagan Administration, and to examine the impact these policies have on the Midwest energy scene. The conference dealt with issues unique to Illinois as well as those facing the entire nation. A separate abstract was prepared for each of the 30 individual presentations.

  3. 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.

  4. Fiscalini Farms Renewable Energy Power Generation Project

    SciTech Connect

    2009-02-01

    Funded by the American Recovery and Reinvestment Act of 2009 Fiscalini Farms L.P., in collaboration with University of the Pacific, Biogas Energy, Inc., and the University of California at Berkeley will measure and analyze the efficiency and regulatory compliance of a renewable energy system for power generation. The system will utilize digester gas from an anaerobic digester located at the Fiscalini Farms dairy for power generation with a reciprocating engine. The project will provide power, efficiency, emissions, and cost/benefit analysis for the system and evaluate its compliance with federal and California emissions standards.

  5. 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.

  6. Maximum gravitational-wave energy emissible in magnetar flares

    SciTech Connect

    Corsi, Alessandra; Owen, Benjamin J.

    2011-05-15

    Recent searches of gravitational-wave data raise the question of what maximum gravitational-wave energies could be emitted during gamma-ray flares of highly magnetized neutron stars (magnetars). The highest energies ({approx}10{sup 49} erg) predicted so far come from a model [K. Ioka, Mon. Not. R. Astron. Soc. 327, 639 (2001), http://adsabs.harvard.edu/abs/2001MNRAS.327..639I] in which the internal magnetic field of a magnetar experiences a global reconfiguration, changing the hydromagnetic equilibrium structure of the star and tapping the gravitational potential energy without changing the magnetic potential energy. The largest energies in this model assume very special conditions, including a large change in moment of inertia (which was observed in at most one flare), a very high internal magnetic field, and a very soft equation of state. Here we show that energies of 10{sup 48}-10{sup 49} erg are possible under more generic conditions by tapping the magnetic energy, and we note that similar energies may also be available through cracking of exotic solid cores. Current observational limits on gravitational waves from magnetar fundamental modes are just reaching these energies and will beat them in the era of advanced interferometers.

  7. 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

  8. Characteristics of short-crested waves and currents behind offshore man-made island type power plant

    SciTech Connect

    Ikeno, Masaaki; Kajima, Ryoichi; Matsuyama, Masafumi; Sakakiyama, Tsutomu

    1995-12-31

    This paper describes the diffracted waves with breaking and the nearshore currents caused by short-crested waves, behind a man-made island, on which nuclear power plants are constructed. Firstly, hydraulic model tests with a multi-directional wave maker were performed. Effects of the irregularity and directional spreading of waves, and the effects of cooling water intake flow on diffracted waves and nearshore currents behind a man-made island, were investigated experimentally. Secondly, a numerical model was developed to simulate deformation of multi-directional irregular waves and nearshore currents. The validity of the numerical model was verified through comparison with the experimental results.

  9. Power combiner with high power capacity and high combination efficiency for two phase-locked relativistic backward wave oscillators

    NASA Astrophysics Data System (ADS)

    Xiao, Renzhen; Deng, Yuqun; Wang, Yue; Song, Zhimin; Li, Jiawei; Sun, Jun; Chen, Changhua

    2015-09-01

    To realize power combination of two phase-locked relativistic backward wave oscillators (RBWOs), a compact power combiner is designed and investigated by 3-D particle-in-cell (PIC) simulation and experiment. The power combiner consists of two TM01-TE11 serpentine mode converters with a common output. When the two incident ports are fed with TM01 modes with a relative phase of 180° and power of 2.5 GW at each port, the conversion efficiency from the incident TM01 modes to the combined TE11 mode is 95.2% at 9.3 GHz, and the maximum electric field in the combiner is 714 kV/cm. The PIC simulation shows that the output power from the common port is 4.2 GW when the power combiner is connected to the two RBWOs with input signals, both producing 2.2 GW microwave, corresponding to a combination efficiency of 95.4%. In the high power microwave test, a method is proposed to obtain the combination efficiency without breaking the vacuum, which is 94.1% when the two phase-locked RBWOs output 1.8 GW and 2.2 GW. The power capacity of multi-gigawatts has been demonstrated.

  10. 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.

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

    SciTech Connect

    2006-03-01

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

  12. 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.

  13. The influence of spatially and temporally high-resolution wind forcing on the power input to near-inertial waves in the ocean

    NASA Astrophysics Data System (ADS)

    Rimac, Antonija; von Storch, Jin-Song; Eden, Carsten

    2013-04-01

    The estimated power required to sustain global general circulation in the ocean is about 2 TW. This power is supplied with wind stress and tides. Energy spectrum shows pronounced maxima at near-inertial frequency. Near-inertial waves excited by high-frequency winds represent an important source for deep ocean mixing since they can propagate into the deep ocean and dissipate far away from the generation sites. The energy input by winds to near-inertial waves has been studied mostly using slab ocean models and wind stress forcing with coarse temporal resolution (e.g. 6-hourly). Slab ocean models lack the ability to reproduce fundamental aspects of kinetic energy balance and systematically overestimate the wind work. Also, slab ocean models do not account the energy used for the mixed layer deepening or the energy radiating downward into the deep ocean. Coarse temporal resolution of the wind forcing strongly underestimates the near-inertial energy. To overcome this difficulty we use an eddy permitting ocean model with high-frequency wind forcing. We establish the following model setup: We use the Max Planck Institute Ocean Model (MPIOM) on a tripolar grid with 45 km horizontal resolution and 40 vertical levels. We run the model with wind forcings that vary in horizontal and temporal resolution. We use high-resolution (1-hourly with 35 km horizontal resolution) and low-resolution winds (6-hourly with 250 km horizontal resolution). We address the following questions: Is the kinetic energy of near-inertial waves enhanced when high-resolution wind forcings are used? If so, is this due to higher level of overall wind variability or higher spatial or temporal resolution of wind forcing? How large is the power of near-inertial waves generated by winds? Our results show that near-inertial waves are enhanced and the near-inertial kinetic energy is two times higher (in the storm track regions 3.5 times higher) when high-resolution winds are used. Filtering high-resolution winds in space and time, the near-inertial kinetic energy reduces. The reduction is faster when a temporal filter is used suggesting that the high-frequency wind forcing is more efficient in generating near-inertial wave energy than the small-scale wind forcing. Using low-resolution wind forcing the wind generated power to near-inertial waves is 0.55 TW. When we use high-resolution wind forcing the result is 1.6 TW meaning that the result increases by 300%.

  14. 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…

  15. ENERGY, POWER AND ENVIRONMENT (Environmental Analytical Chemistry)

    E-print Network

    Sherrill, David

    ENERGY, POWER AND ENVIRONMENT (Environmental Analytical Chemistry) CHEM 6284/CHEM 4803 Fall 2014 3 credit hours J. (Art) Janata jiri.janata@chemistry.gatech.edu; 404 894 4828 Since the dawn of history and with it the environmental cost of this transformation. The balance between demand for energy and the environmental impact

  16. Fluid Power Systems. Energy Technology Series.

    ERIC Educational Resources Information Center

    Center for Occupational Research and Development, Inc., Waco, TX.

    This course in fluid power systems is one of 16 courses in the Energy Technology Series developed for an Energy Conservation-and-Use Technology curriculum. Intended for use in two-year postsecondary technical institutions to prepare technicians for employment, the courses are also useful in industry for updating employees in company-sponsored…

  17. 'People Power' Saves Plant Energy 

    E-print Network

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

    1981-01-01

    in the refinery. T hey can thus be kept informed about the committee's activities. Group lectures. An excellent method for stimulating awareness of conservation has been the group lecture. Very often the blunt statement: "Con serve energy'." is met... with the question, "How?" A general format for an energy conservation lecture has been developed. It includes a slide presenta tion. The lecture lasts about 45 minutes. Since it can be given to large groups, many people can be exposed to the conservation ethic...

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

    SciTech Connect

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

    2012-01-15

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

  19. Super-radiant backward-wave oscillators with enhanced power conversion

    SciTech Connect

    Rostov, V. V.; Savilov, A. V.

    2013-02-15

    We propose a method for a very significant increase of the peak power of a backward-wave electron oscillator operating in the non-stationary regime of the super-radiation of short rf pulses. This method is based on sectioning: a regular self-oscillator section is supported with a section providing amplification of the super-radiant pulse. Profiling of a resonant parameter in the amplifying section is used to avoid the parasitic self-excitation and to increase the efficiency of the electron-wave interaction. In such systems, the conversion factor (the ratio between the rf pulse power and the electron beam power) can achieve a few hundred percent.

  20. 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

  1. 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.

  2. 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.

  3. 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.

  4. Low-Power Testing of Losses in Millimeter-Wave Transmission Lines for High-Power Applications

    PubMed Central

    Han, S. T.; Comfoltey, E. N.; Shapiro, M. A.; Sirigiri, J. R.; Tax, D. S.; Temkin, R. J.; Woskov, P. P.; Rasmussen, D. A.

    2008-01-01

    We report the measurement of small losses in transmission line (TL) components intended for high-power millimeter-wave applications. Measurements were made using two different low-power techniques: a coherent technique using a vector network analyzer (VNA) and an incoherent technique using a radiometer. The measured loss in a 140 GHz 12.7 mm diameter TL system, consisting of 1.7 m of circular corrugated waveguide and three miter bends, is dominated by the miter bend loss. The measured loss was 0.3±0.1 dB per miter bend using a VNA; and 0.22±0.1 dB per miter bend using a radiometer. Good agreement between the two measurement techniques implies that both are useful for measuring small losses. To verify the methodology, the VNA technique was employed to measure the extremely small transmission loss in a 170 GHz ITER prototype TL system consisting of three lengths of 1 m, 63.5 mm diameter, circular corrugated waveguide and two miter bends. The measured loss of 0.05±0.02 dB per miter bend may be compared with the theoretical loss of 0.027 dB per miter bend. These results suggest that low-power testing of TL losses, utilizing a small, simple TL system and a VNA, is a reliable method for evaluating performance of low-loss millimeter-wave TL components intended for use in high-power applications. PMID:19081774

  5. Energy storage options for space power

    SciTech Connect

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

    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 storage densities of 1500 to 2000 kJ/kg at temperatures to 1675/sup 0/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 (approx. 550 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.

  6. Experimental study on load characteristics in a floating type pendulum wave energy converter

    NASA Astrophysics Data System (ADS)

    Murakami, Tengen; Imai, Yasutaka; Nagata, Shuichi

    2014-10-01

    A floating type pendulum wave energy converter (FPWEC) with a rotary vane pump as the power take-off system was proposed by Watabe et al. in 1998. They showed that this device had high energy conversion efficiency. In the previous research, the authors conducted 2D wave tank tests in regular waves to evaluate the generating efficiency of FPWEC with a power take-off system composed of pulleys, belts and a generator. As a result, the influence of the electrical load on the generating efficiency was shown. Continuously, the load characteristics of FPWEC are pursued experimentally by using the servo motors to change the damping coefficient in this paper. In a later part of this paper, the motions of the model with the servo motors are compared with that of the case with the same power take-off system as the previous research. From the above experiment, it may be concluded that the maximum primary conversion efficiency is achieved as high as 98% at the optimal load.

  7. Experimental demonstration of a squeezing enhanced power recycled Michelson interferometer for gravitational wave detection

    E-print Network

    Kirk McKenzie; Ben C. Buchler; Daniel A. Shaddock; Ping Koy Lam; David E. McClelland

    2002-05-09

    Interferometric gravitational wave detectors are expected to be limited by shot noise at some frequencies. We experimentally demonstrate that a power recycled Michelson with squeezed light injected into the dark port can overcome this limit. An improvement in the signal-to-noise ratio of 2.3dB is measured and locked stably for long periods of time. The configuration, control and signal readout of our experiment are compatible with current gravitational wave detector designs. We consider the application of our system to long baseline interferometer designs such as LIGO.

  8. Experimental demonstration of a squeezing enhanced power recycled Michelson interferometer for gravitational wave detection

    E-print Network

    McKenzie, K; Shaddock, D A; Lam, P K; McClelland, D E; Kenzie, Kirk Mc; Buchler, Ben C.; Shaddock, Daniel A.; Lam, Ping Koy; Clelland, David E. Mc

    2002-01-01

    Interferometric gravitational wave detectors are expected to be limited by shot noise at some frequencies. We experimentally demonstrate that a power recycled Michelson with squeezed light injected into the dark port can overcome this limit. An improvement in the signal-to-noise ratio of 2.3dB is measured and locked stably for long periods of time. The configuration, control and signal readout of our experiment are compatible with current gravitational wave detector designs. We consider the application of our system to long baseline interferometer designs such as LIGO.

  9. 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.

  10. Energy dissipation via electron energization in standing shear Alfvn waves

    E-print Network

    Wright, Andrew N.

    toroidal field line resonance FLR centered on an L=10 closed dipolar magnetic field line. The model currents can be a significant sink of Alfvén wave energy depending on the width of the flux tube. For a FLR model to consider a full standing FLR system in a proper 2D dipolar geometry with self

  11. Solar energy converter using surface plasma waves

    NASA Technical Reports Server (NTRS)

    Anderson, L. M. (inventor)

    1984-01-01

    Sunlight is dispersed over a diffraction grating formed on the surface of a conducting film on a substrate. The angular dispersion controls the effective grating period so that a matching spectrum of surface plasmons is excited for parallel processing on the conducting film. The resulting surface plasmons carry energy to an array of inelastic tunnel diodes. This solar energy converter does not require different materials for each frequency band, and sunlight is directly converted to electricity in an efficient manner by extracting more energy from the more energetic photons.

  12. 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.

  13. Energy management system functions in deregulated power systems 

    E-print Network

    Magnago, Fernando Hugo

    1997-01-01

    The market structures for electric energy and power are changing. In the past interconnected electric utility systems dealt only with each other to buy and sell power and energy. In recent times, the electric power industry ...

  14. 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.

  15. 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.

  16. Low-power, low-rate ultrasonic communications system transmitting axially along a cylindrical pipe using transverse waves.

    PubMed

    Chakraborty, Soumya; Saulnier, Gary J; Wilt, Kyle W; Curt, Edward; Scarton, Henry A; Litman, Robert B

    2015-10-01

    Acoustic-electric channels have been used in the recent past to send power and data through thin metallic barriers. Acoustic-electric channels formed along a structure which are highly attenuative and nonreverberant could have potential applications in aerospace, nuclear, and oil industries, among others. This work considers data transmission along the length of a cylindrical pipe both when in air and when filled and immersed in water using shear waves of transverse polarity. To combat the effects of frequency selectivity and to address the available power constraints, a simple modulation scheme using noncoherent demodulation is employed for data transmission: chirp-on-off keying (Chirp-OOK). The wideband nature of the chirp waveform provides resilience against nulls in the channel response while making it possible to implement a simple noncoherent energy detector. Monte Carlo simulation results using measured channel responses suggest that the bit error rate performance of the scheme matches quite closely with the theoretical results. The energy detector performance is independent of the type of the channel used as long as intersymbol-interference is negligible and same received Eb/N0 is maintained. A low-power prototype hardware system was implemented using microcontrollers, commercial ICs, and custom circuits. Successful data transmission was achieved across the 4.8 m length of pipe (in air and water) for a data rate of 100 bps using approximately 5 mW of transmit power. PMID:26470041

  17. 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.

  18. Self Adaptive Air Turbine for Wave Energy Conversion Using Shutter Valve and OWC Heoght Control System

    SciTech Connect

    Di Bella, Francis A

    2014-09-29

    An oscillating water column (OWC) is one of the most technically viable options for converting wave energy into useful electric power. The OWC system uses the wave energy to “push or pull” air through a high-speed turbine, as illustrated in Figure 1. The turbine is typically a bi-directional turbine, such as a Wells turbine or an advanced Dennis-Auld turbine, as developed by Oceanlinx Ltd. (Oceanlinx), a major developer of OWC systems and a major collaborator with Concepts NREC (CN) in Phase II of this STTR effort. Prior to awarding the STTR to CN, work was underway by CN and Oceanlinx to produce a mechanical linkage mechanism that can be cost-effectively manufactured, and can articulate turbine blades to improve wave energy capture. The articulation is controlled by monitoring the chamber pressure. Funding has been made available from the U.S. Department of Energy (DOE) to CN (DOE DE-FG-08GO18171) to co-share the development of a blade articulation mechanism for the purpose of increasing energy recovery. However, articulating the blades is only one of the many effective design improvements that can be made to the composite subsystems that constitute the turbine generator system.

  19. Ocean Wave Energy Estimation Using Active Satellite Imagery as a Solution of Energy Scarce in Indonesia Case Study: Poteran Island's Water, Madura

    NASA Astrophysics Data System (ADS)

    Nadzir, Z. A.; Karondia, L. A.; Jaelani, L. M.; Sulaiman, A.; Pamungkas, A.; Koenhardono, E. S.; Sulisetyono, A.

    2015-10-01

    Ocean wave energy is one of the ORE (Ocean Renewable Energies) sources, which potential, in which this energy has several advantages over fossil energy and being one of the most researched energy in developed countries nowadays. One of the efforts for mapping ORE potential is by computing energy potential generated from ocean wave, symbolized by Watt per area unit using various methods of observation. SAR (Synthetic Aperture Radar) is one of the hyped and most developed Remote Sensing method used to monitor and map the ocean wave energy potential effectively and fast. SAR imagery processing can be accomplished not only in remote sensing data applications, but using Matrices processing application as well such as MATLAB that utilizing Fast Fourier Transform and Band-Pass Filtering methods undergoing Pre-Processing stage. In this research, the processing and energy estimation from ALOSPALSAR satellite imagery acquired on the 5/12/2009 was accomplished using 2 methods (i.e Magnitude and Wavelength). This resulted in 9 potential locations of ocean wave energy between 0-228 W/m2, and 7 potential locations with ranged value between 182-1317 W/m2. After getting through buffering process with value of 2 km (to facilitate the construction of power plant installation), 9 sites of location were estimated to be the most potential location of ocean wave energy generation in the ocean with average depth of 8.058 m and annual wind speed of 6.553 knot.

  20. A quasi-optical resonant ring for high power millimeter-wave testing

    SciTech Connect

    Bigelow, T.S.

    1997-08-01

    Gyrotrons of > 1-MW cw power in the 110- to 160-GHz frequency range with HE{sub 11} output beams are being developed for electron cyclotron heating (ECH) of plasmas. Windows are required for gyrotrons and for waveguide transmission systems at the plasma device to provide vacuum isolation and containment. Windows ar difficult to build for these systems because the window dielectric losses increase with frequency and the centrally peaked output power beam concentrates the power deposition near the center. Development and testing of a window independent of gyrotron development is desirable since window failure on a cw gyrotron usually means an expensive reprocessing of the entire tube or possibly even total loss. A quasi-optical resonant ring is being developed for testing of millimeter wave components, windows and low-loss materials at very high power levels using medium power level sources. The resonant ring generates a traveling wave resonance of uniform amplitude along the waveguide that is ideal for testing components and materials. Both smooth-wall TE{sub 01} mode and a corrugated-wall HE{sub 11} mode versions have been constructed. These units use highly oversized waveguide and four miter bends to form a quasi-optical resonant ring. A perforated plate miter bend serves as the input directional coupler. A water-cooled tube array is being designed for a coupler capable high-power cw operation. A theoretical power gain of > 10 is possible using the 63.5 mm HE{sub 11} version at 53 GHz. Low power measurements have been performed to confirm the operation and > 1.5 MW high power tests using a 200 kW gyrotron are expected in the near future.

  1. Modular Low-Heater-Power Cathode/Electron Gun Assembly for Microwave and Millimeter Wave Traveling Wave Tubes

    NASA Technical Reports Server (NTRS)

    Wintucky, Edwin G.

    2000-01-01

    A low-cost, low-mass, electrically efficient, modular cathode/electron gun assembly has been developed by FDE Inc. of Beaverton, Oregon, under a Small Business Innovation Research (SBIR) contract with the NASA Glenn Research Center at Lewis Field. This new assembly offers significant improvements in the design and manufacture of microwave and millimeter wave traveling-wave tubes (TWT's) used for radar and communications. It incorporates a novel, low-heater-power, reduced size and mass, high-performance barium dispenser type thermionic cathode and provides for easy integration of the cathode into a large variety of conventional TWT circuits. Among the applications are TWT's for Earth-orbiting communication satellites and for deep space communications, where future missions will require smaller spacecraft, higher data transfer rates (higher frequencies and radiofrequency output power), and greater electrical efficiency. A particularly important TWT application is in the microwave power module (a hybrid microwave/millimeter wave amplifier consisting of a low-noise solid-state driver, a small TWT, and an electronic power conditioner integrated into a single compact package), where electrical efficiency and thermal loading are critical factors and lower cost is needed for successful commercialization. The design and fabrication are based on practices used in producing cathode ray tubes (CRT's), which is one of the most competitive and efficient manufacturing operations in the world today. The approach used in the design and manufacture of thermionic cathodes and electron guns for CRT's has been optimized for fully automated production, standardization of parts, and minimization of costs. It is applicable to the production of similar components for microwave tubes, with the additional benefits of low mass and significantly lower cathode heater power (less than half that of dispenser cathodes presently used in TWT s). Modular cathode/electron gun assembly. The modular cathode/electron gun assembly consists of four subassemblies the cathode, the focus electrode, the header (including the electrical feedthroughs), and the gun envelope (including the anode) a diagram of which is shown. The modular construction offers a number of significant advantages, including flexibility of design, interchangeability of parts, and a drop-in final assembly procedure for quick and accurate alignment. The gun can accommodate cathodes ranging in size from 0.050 to 0.250-in. in diameter and is applicable to TWT's over a broad range of sizes and operating parameters, requiring the substitution of only a few parts: that is, the cathode, focus electrode, and anode. The die-pressed cathode pellets can be made with either flat or concave (Pierce gun design) emitting surfaces. The gun can be either gridded (pulse operation) or ungridded (continuous operation). Important factors contributing to low cost are the greater use of CRT materials and parts, the standardization of processes (welding and mechanical capture), and tooling amenable to automated production. Examples are the use of simple shapes, drawn or stamped metal parts, and parts joined by welding or mechanical capture. Feasibility was successfully demonstrated in the retrofit and testing of a commercial Kaband (22-GHz) TWT. The modular cathode/electron gun assembly was computer modeled to replicate the performance of the original electron gun and fabricated largely from existing CRT parts. Significant test results included demonstration of low heater power (1.5-W, 1010 C brightness temperature for a 0.085-in.-diameter cathode), mechanical ruggedness (100g shock and vibration tests in accordance with military specifications (MIL specs)), and a very fast warmup. The results of these tests indicate that the low-cost CRT manufacturing approach can be used without sacrificing performance and reliability.

  2. A Skin-attachable Flexible Piezoelectric Pulse Wave Energy Harvester

    NASA Astrophysics Data System (ADS)

    Yoon, Sunghyun; Cho, Young-Ho

    2014-11-01

    We present a flexible piezoelectric generator, capable to harvest energy from human arterial pulse wave on the human wrist. Special features and advantages of the flexible piezoelectric generator include the multi-layer device design with contact windows and the simple fabrication process for the higher flexibility with the better energy harvesting efficiency. We have demonstrated the design effectiveness and the process simplicity of our skin- attachable flexible piezoelectric pulse wave energy harvester, composed of the sensitive P(VDF-TrFE) piezoelectric layer on the flexible polyimide support layer with windows. We experimentally characterize and demonstrate the energy harvesting capability of 0.2~1.0?W in the Human heart rate range on the skin contact area of 3.71cm2. Additional physiological and/or vital signal monitoring devices can be fabricated and integrated on the skin attachable flexible generator, covered by an insulation layer; thus demonstrating the potentials and advantages of the present device for such applications to the flexible multi-functional selfpowered artificial skins, capable to detect physiological and/or vital signals on Human skin using the energy harvested from arterial pulse waves.

  3. Low-current traveling wave tube for use in the microwave power module

    NASA Technical Reports Server (NTRS)

    Palmer, Raymond W.; Ramins, Peter; Force, Dale A.; Dayton, James A.; Ebihara, Ben T.; Gruber, Robert P.

    1993-01-01

    The results of a traveling-wave-tube/multistage depressed-collector (TWT-MDC) design study in support of the Advanced Research Projects Agency/Department of Defense (ARPA/DOD) Microwave Power Module (MPM) Program are described. The study stressed the possible application of dynamic and other tapers to the RF output circuit of the MPM traveling wave tube as a means of increasing the RF and overall efficiencies and reducing the required beam current (perveance). The results indicate that a highly efficient, modified dynamic velocity taper (DVT) circuit can be designed for the broadband MPM application. The combination of reduced cathode current (lower perveance) and increased RF efficiency leads to (1) a substantially higher overall efficiency and reduction in the prime power to the MPM, and (2) substantially reduced levels of MDC and MPM heat dissipation, which simplify the cooling problems. However, the selected TWT circuit parameters need to be validated by cold test measurements on actual circuits.

  4. 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

  5. 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

  6. Wave goodbye to flat batteries: tiny windmills could power smartphones on the go

    E-print Network

    Chiao, Jung-Chih

    /read/wave-goodbye-to-flat-batteries-tiny-windmills-could-... #12;14 Social Security Benefits You Haven't Been Taking Moneynews Secrets of Building Muscle: It ­ for example, thousands of the micro-windmills could be mounted on the outside of a building to generate energy

  7. Novel Nuclear Powered Photocatalytic Energy Conversion

    SciTech Connect

    White,John R.; Kinsmen,Douglas; Regan,Thomas M.; Bobek,Leo M.

    2005-08-29

    The University of Massachusetts Lowell Radiation Laboratory (UMLRL) is involved in a comprehensive project to investigate a unique radiation sensing and energy conversion technology with applications for in-situ monitoring of spent nuclear fuel (SNF) during cask transport and storage. The technology makes use of the gamma photons emitted from the SNF as an inherent power source for driving a GPS-class transceiver that has the ability to verify the position and contents of the SNF cask. The power conversion process, which converts the gamma photon energy into electrical power, is based on a variation of the successful dye-sensitized solar cell (DSSC) design developed by Konarka Technologies, Inc. (KTI). In particular, the focus of the current research is to make direct use of the high-energy gamma photons emitted from SNF, coupled with a scintillator material to convert some of the incident gamma photons into photons having wavelengths within the visible region of the electromagnetic spectrum. The high-energy gammas from the SNF will generate some power directly via Compton scattering and the photoelectric effect, and the generated visible photons output from the scintillator material can also be converted to electrical power in a manner similar to that of a standard solar cell. Upon successful implementation of an energy conversion device based on this new gammavoltaic principle, this inherent power source could then be utilized within SNF storage casks to drive a tamper-proof, low-power, electronic detection/security monitoring system for the spent fuel. The current project has addressed several aspects associated with this new energy conversion concept, including the development of a base conceptual design for an inherent gamma-induced power conversion unit for SNF monitoring, the characterization of the radiation environment that can be expected within a typical SNF storage system, the initial evaluation of Konarka's base solar cell design, the design and fabrication of a range of new cell materials and geometries at Konarka's manufacturing facilities, and the irradiation testing and evaluation of these new cell designs within the UML Radiation Laboratory. The primary focus of all this work was to establish the proof of concept of the basic gammavoltaic principle using a new class of dye-sensitized photon converter (DSPC) materials based on KTI's original DSSC design. In achieving this goal, this report clearly establishes the viability of the basic gammavoltaic energy conversion concept, yet it also identifies a set of challenges that must be met for practical implementation of this new technology.

  8. Sensitivity of Radar Wave Propagation Power to the Marine Atmospheric Boundary Layer

    NASA Astrophysics Data System (ADS)

    Lentini, N.; Hackett, E. E.

    2014-12-01

    Radar is a remote sensor used for scientific, meteorological, and military applications. Radar waves are affected by the medium through which they propagate, impacting the accuracy of radar measurements. Thus, environmental effects should be understood and quantified. The marine atmospheric boundary layer (MABL) is highly dynamic and turbulent, and affects radar wave propagation. The ocean surface roughness impacts scattering behavior. These effects cause variability in constructive and destructive interference patterns due to reflection from the ocean surface, known as multipath. The atmospheric effects cause radar waves to attenuate and refract; this study focuses on the refractive effects. A high-fidelity, physics-based, parabolic wave equation simulation is used to model the radar propagation and accounts for effects of the rough ocean surface (wind seas and swell) as well as variable refractivity with height and range. We use a robust, variance based, sensitivity analysis method called the Extended Fourier Amplitude Sensitivity Test to quantify which environmental parameters have the most significant effect on the modeled radar wave propagation. In this sensitivity study, the environment is parameterized by 16 variables, 8 ocean surface and 8 atmospheric. Sensitivity analysis is performed for 3 radar frequencies (3, 9, and 15 GHz) and 2 polarizations (horizontal and vertical). Results indicate that radar wave propagation is more sensitive to atmospheric parameters than ocean surface parameters. The mixed layer has the most far-reaching effect over the entire model domain (a range of 60 km and altitudes up to 1 km), characterized by its height and refractivity gradient. The remaining important factors have a predominantly local effect in the region where they occur in the MABL atmospheric structure. At low altitudes, radar wave propagation power is most sensitive to the gradient and curvature of the vertical refractivity profile. This research provides insight into which aspects of the environment would need to be known with high accuracy to enable corrections for these environmental effects.

  9. A Self-powered Power Management Circuit for Energy Harvested by a Piezoelectric Cantilever

    E-print Network

    Ha, Dong S.

    A Self-powered Power Management Circuit for Energy Harvested by a Piezoelectric Cantilever Na Kong1 of a self-powered power management circuit for energy harvested by a piezoelectric cantilever. A full output, matches the source impedance, and generates a regulated DC output provided the input power

  10. Plasma instabilities in the high-latitude E region induced by high-power radio waves

    SciTech Connect

    Chaturvedi, P.K.; Ossakow, S.L. )

    1990-09-01

    The effect of a high-frequency powerful pump wave on high-latitude E region low-frequency plasma instabilities is theoretically considered. The growth rates and threshold criteria are calculated for instabilities associated with the electrojet (Farley-Buneman, gradient drift) and with higher-altitude parallel currents (ion acoustic, ion cyclotron, current convective). The results are discussed in the context of present ionospheric modification (heating) experiments.

  11. Imaging ultrasonic dispersive guided wave energy in long bones using linear radon transform.

    PubMed

    Tran, Tho N H T; Nguyen, Kim-Cuong T; Sacchi, Mauricio D; Le, Lawrence H

    2014-11-01

    Multichannel analysis of dispersive ultrasonic energy requires a reliable mapping of the data from the time-distance (t-x) domain to the frequency-wavenumber (f-k) or frequency-phase velocity (f-c) domain. The mapping is usually performed with the classic 2-D Fourier transform (FT) with a subsequent substitution and interpolation via c = 2?f/k. The extracted dispersion trajectories of the guided modes lack the resolution in the transformed plane to discriminate wave modes. The resolving power associated with the FT is closely linked to the aperture of the recorded data. Here, we present a linear Radon transform (RT) to image the dispersive energies of the recorded ultrasound wave fields. The RT is posed as an inverse problem, which allows implementation of the regularization strategy to enhance the focusing power. We choose a Cauchy regularization for the high-resolution RT. Three forms of Radon transform: adjoint, damped least-squares, and high-resolution are described, and are compared with respect to robustness using simulated and cervine bone data. The RT also depends on the data aperture, but not as severely as does the FT. With the RT, the resolution of the dispersion panel could be improved up to around 300% over that of the FT. Among the Radon solutions, the high-resolution RT delineated the guided wave energy with much better imaging resolution (at least 110%) than the other two forms. The Radon operator can also accommodate unevenly spaced records. The results of the study suggest that the high-resolution RT is a valuable imaging tool to extract dispersive guided wave energies under limited aperture. PMID:25282483

  12. Novel high-power subterahertz-range radial surface wave oscillator

    NASA Astrophysics Data System (ADS)

    Chen, Zaigao; Wang, Jianguo; Wang, Yue; Wang, Guangqiang; Li, Shuang; Cheng, Guoxin

    2015-06-01

    A novel high-power subterahertz-range radial surface wave oscillator (SWO), in which the electron beam is emitted radially and interacts with the slow wave structure (SWS) machined on a planar plate, is presented in this paper. Compared to the axial SWO where the electron beam is emitted axially and interacts with the SWS machined on the inner wall of a cylindrical waveguide, the radial SWO has two advantages. One is that fabrication of the radial SWS is much easier than that of the axial SWO. The other is that the radial SWO is a low-impedance device, it can produce much higher current than the axial SWO when they are driven by the same driven voltage, and hence, it may generate much higher output power. Particle-in-cell simulation results demonstrate that the proposed radial SWO driven by the voltage of 312 kV can produce the terahertz wave with the mean output power of 680 MW at the frequency of 0.142 THz, it has a very pure TM01 mode and the higher modes can be effectively suppressed.

  13. Interactive power flow characteristics of an integrated equipment—nonlinear isolator—travelling flexible ship excited by sea waves

    NASA Astrophysics Data System (ADS)

    Xiong, Y. P.; Xing, J. T.; Price, W. G.

    2005-10-01

    A nonlinear interactive system comprising of equipment, nonlinear isolator and travelling flexible ship excited by waves is studied from a vibratory power flow viewpoint to examine its dynamical behaviour and power flow characteristics. The mathematical model describing the dynamics of this nonlinear interactive system is developed. Dynamical interactions between equipment, nonlinear isolator, flexible foundation and water waves are addressed. The nonlinearities of the isolator are characterized by a general pth power model for damping and qth power for stiffness. A harmonic balance method is adopted to derive the steady-state harmonic response of the nonlinear system. A Newton-Raphson iteration process in association with an efficient numerical algorithm is used to obtain the solutions of this nonlinear problem. Through simulations the dynamical behaviour, power flow characteristics and isolation efficiency of this complex nonlinear interaction system are investigated. For different values of power p and q, different wave excitations and flexible or rigid ship, the power transmitted to the equipment and power flow transmission ratios are calculated and analysed. The effect of the vibration source with different wave conditions of the seaway is studied through examining its vibratory power input to the overall system. The effects of the assumptions of flexible or rigid ship, the nonlinearities on the power flows in the system are examined. Nonlinear power flow phenomena and mechanisms are revealed, which provides an insight to the understanding of power flow characteristics in nonlinear systems. Practical guidelines for the design of vibration isolation systems applicable to maritime engineering are suggested.

  14. 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)

  15. 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.

  16. SEPTEMBER 2006 MOUM ET. AL. 1 Energy Transport by Nonlinear Internal Waves

    E-print Network

    Pierce, Stephen

    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

  17. Estimating Internal Wave Energy Fluxes in the Ocean JONATHAN D. NASH

    E-print Network

    Balasubramanian, Ravi

    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

  18. APRIL 2006 MOUM ET. AL. 1 Energy Transport by Nonlinear Internal Waves

    E-print Network

    Pierce, Stephen

    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

  19. 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

  20. Shell-instability generated waves by low energy electrons on converging magnetic field lines

    E-print Network

    California at Berkeley, University of

    .g., magnetosonic ion waves [Perraut et al., 1982], lower-hybrid waves [Bingham et al., 1999], ion-Bernstein and ion cyclotron harmonics, upper-hybrid as well as the RX mode. Local wave spectra observations are consistentShell-instability generated waves by low energy electrons on converging magnetic field lines D

  1. SUPPORTING SOLAR ENERGY DEVELOPMENT THROUGH GREEN POWER MARKETS Blair Swezey

    E-print Network

    SUPPORTING SOLAR ENERGY DEVELOPMENT THROUGH GREEN POWER MARKETS Blair Swezey Lori Bird Christy systems has been a feature of many green power products offered to consumers. While green power markets in part through green power marketing. This paper describes the use of solar energy in green power

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

    DOEpatents

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

    1993-01-01

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

  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. Highly efficient terahertz wave filter for high-power laser beam separation

    SciTech Connect

    Guo, Bo; Cai, Bin E-mail: ymzhu@usst.edu.cn; Zhu, YiMing E-mail: ymzhu@usst.edu.cn; Tang, Jun

    2014-12-01

    In this study, we design and fabricate a two-layer device based on the Rayleigh scattering theory for effectively separating high-energy pump-laser-generated terahertz (THz) waves. The basic layer is comprised of cyclo olefin polymer and silicon nanoparticles, which can obstruct the propagation of the 800-nm, high-energy pump laser through scattering and absorption effects while permitting THz waves to pass through. In order to improve the laser damage threshold of the basic layer, an additional layer, which is composed of hollow silica nanoparticles, is used to diffuse the incident high-energy laser beam. Through this two-layer structure, a high 800-nm laser threshold and highly transparent THz region filter are fabricated.

  5. Horizontal displacements contribution to tsunami wave energy balance

    E-print Network

    Dutykh, Denys; Chubarov, Leonid; Shokin, Yuriy

    2010-01-01

    The main reason for the generation of tsunamis is the deformation of the bottom of the ocean caused by an underwater earthquake. Usually, only the vertical bottom motion is taken into accound while the horizontal displacements are neglected. In the present paper we study both the vertical and the horizontal bottom motion while we propose a novel methodology for reconstructing the bottom coseismic displacements field which is transmitted to the free surface using a new three-dimensional Weakly Nonlinear (WN) approach. We pay a special attention to the evolution of kinetic and potential energies of the resulting wave while the contribution of horizontal displacements into wave energy balance is also quantified. Approaches proposed in this study are illustrated on the July 17, 2006 Java tsunami.

  6. Ultra low-power hybrid spintronics-straintronics clocked with Surface Acoustic Waves (SAW)

    NASA Astrophysics Data System (ADS)

    Salehi Fashami, Mohammad; Bandyopadhyay, Supriyo; Atulasimha, Jayasimha

    2014-03-01

    The study of magnetization dynamics in magnetostrictive materials triggered with surface acoustic waves (SAWs) is of great interest not only from a fundamental point of view, but also for potential applications in energy efficient nanomagnetic computing. In this presentation, we model magnetization dynamics in dipole coupled arrays of nanomagnets clocked by acoustic waves. Specifically, this theoretical work demonstrates the feasibility of sequential logic devices such as flip-flops by showing that NAND gates and information propagation with cross-over of nanomagnet ``wires'' can be implemented and synchronously clocked with surface acoustic waves. We acknowledge support of the National Science Foundation (NSF) under NSF CAREER grant CCF-1253370, the NEB2020 Grant ECCS-1124714 and SHF grant CCF-1216614 as well as the Semiconductor Research Company (SRC) under NRI task 2203.001.

  7. Excitation of guided ELF-VLF waves through modification of the F{sub 2} ionospheric layer by high-power radio waves

    SciTech Connect

    Markov, G. A.; Belov, A. S.; Komrakov, G. P.; Parrot, M.

    2012-03-15

    The possibility of controlled excitation of ELF-VLF electromagnetic waves through modification of the F{sub 2} ionospheric layer by high-power high-frequency emission is demonstrated in a natural experiment by using the Sura midlatitude heating facility. The excited low-frequency waves can be used to explore the near-Earth space and stimulate the excitation of a magnetospheric maser.

  8. Unbundling of electric power and energy services

    SciTech Connect

    Keith, D.M.; Lewis, B.R.

    1996-12-31

    The world-wide movement to restructure the electric and power and energy industry is now well underway in the United States. The most recent thrust came this year, with the Federal Energy Regulatory Commission`s (FERC`s) issuance on April 24th of new regulations designed to open the interconnected transmission grid to all qualified wholesale users. Other movements have been in the many forms of earlier statutes and regulations promulgated in 1978 to make more efficient use of fuels burned; utility diversification efforts; utility creation of affiliate and subsidiary organizations and operations; introduction into the market of private non-utility power developers; utilities obtaining clearance from the Securities and Exchange Commission (SEC) to venture in international markets; massive mergers and acquisitions; bankruptcies; the entry into the market of nonutility power marketers and brokers, including entities from the gas and securities industries not previously involved in the electric power and energy industry; additional congressional consideration of outright repeal of Holding Company legislation dating back to 1935; some states entering into an era of abandoning the control past in favor of complete re-regulation of the industry on the basis of performance; the coming of Independent System Operators (ISO`s), Regional Transmission Groups (RTG`s), and the possible coming of Capacity Reservation Tariffs (CRT`s), to name a few.

  9. A high power experimental traveling wave antenna for fast wave heating and current drive in DIII-D and relevance to ITER

    SciTech Connect

    Phelps, D.A.; Ikezi, H.; Moeller, C.P.

    1995-10-01

    The impact of a contemplated conversion of the directly driven high power antenna arrays in DIII-D to externally tuned and coupled traveling wave antennas (TWAs) is evaluated based on empirical modeling, computer simulation and low power experiments. A regime of operation is predicted within the TWA passband in which the reflected power from the TWA approaches 0.1% during ELM-free H-mode. Furthermore, this reflected power does not exceed 1% and the optimum phase velocity produced by the TWA decreases less than 5% during ELMs. This resilient operating regime is phase shifted using external tuning stubs, thus providing considerable experimental flexibility. Over 90% plasma coupling efficiency is achieved by recovering the TWA output power using a novel traveling wave recirculator. Combining the above attributes with efficient plasma coupling even at large antenna-plasma distances and the lack of need for dynamic tuning, TWAs appear to offer great promise for ITER.

  10. Multicriteria analysis to evaluate wave energy converters based on their environmental impact: an Italian case study

    NASA Astrophysics Data System (ADS)

    Azzellino, Arianna; Contestabile, Pasquale; Lanfredi, Caterina; Vicinanza, Diego

    2010-05-01

    The exploitation of renewable energy resources is fast becoming a key objective in many countries. Countries with coastlines have particularly valuable renewable energy resources in the form of tides, currents, waves and offshore wind. Due to the visual impact of siting large numbers of energy generating devices (eg. wind turbines) in terrestrial landscapes, considerable attention is now being directed towards coastal waters. Due to their environmental sensitivity, the selection of the most adequate location for these systems is a critical factor. Multi-criteria analysis allows to consider a wide variety of key characteristics (e.g. water depth, distance to shore, distance to the electric grid in land, geology, environmental impact) that may be converted into a numerical index of suitability for different WEC devices to different locations. So identifying the best alternative between an offshore or a onshore device may be specifically treated as a multicriteria problem. Special enphasisi should be given in the multicriteria analysis to the environmental impact issues. The wave energy prospective in the Italian seas is relatively low if compared to the other European countries faced to the ocean. Based on the wave climate, the Alghero site, (NW Sardinia, Italy) is one of the most interesting sites for the wave energy perspective (about 10 kW/m). Alghero site is characterized by a high level of marine biodiversity. In 2002 the area northern to Alghero harbour (Capo Caccia-Isola Piana) was established a Marine Protected Area (MPA). It could be discussed for this site how to choose between the onshore/offshore WEC alternative. An offshore device like Wave Dragon (http://www.wavedragon.net/) installed at -65m depth (width=300m and length=170 m) may approximately produce about 3.6 GWh/y with a total cost of about 9,000,000 €. On the other hand, an onshore device like SSG (http://waveenergy.no/), employed as crown wall for a vertical breakwater to enlarge the present harbour protection, and installed at -10m depth (length=300 m) may produce about 2.7 GWh/y with a total costs of about 12,000,000 €, where only the 50% of the amount are the costs of the SSG device. Obviously the environmental impact of the two solutions is quite different. Aim of this study is to provide a multicriteria decision support framework to evaluate the best WEC typology and location in the perspective of the environmental cost-benefit analysis. The general environmental aspects generated by wave power projects will be described. Colonisation patterns and biofouling will be discussed with particular reference to changes of the seabed and alterations due to new substrates. In addition, impacts for fish, fishery and marine mammals will be also considered. We suggest that wave power projects should be evaluated also on the basis of their environmental impacts in the perspective of the Strategic Environmental Assessment (SEA) analysis, as implemented by the European Commission (SEA Directive 2001/42/EC). The early incorporation of the environmental aspects involved in the evaluation of wave power projects will give the opportunity for early mitigations or design modifications, most likely making wave projects more acceptable in the long run and more suitable for the marine environment.

  11. High power continuous wave microwave system at 3.7 GHz

    NASA Astrophysics Data System (ADS)

    Bora, D.; Dani, S.; Gangopadhyay, S.; Jadav, B.; Jha, M.; Kadia, B. R.; Khilar, P. L.; Kulkarni, S. V.; Kushwah, M.; Patel, A. P.; Parmar, K. G.; Parmar, K. M.; Parmar, P.; Rajnish, K.; Raghuraj, S.; Rao, S. L.; Samanta, K. K.; Sathyanarayana, K.; Shah, P.; Sharma, P. K.; Srinivas, Y. S. S.; Trivedi, R. G.; Verghese, G.

    2001-03-01

    The lower hybrid current drive (LHCD) system is an important system in superconducting steady state tokamak (SST-1). It is used to drive and maintain the plasma current for 1000 s with a duty cycle of 17%. The LHCD system is being designed to launch 1 MW of radio frequency (rf) power at 3.7 GHz. The rf source is comprised of two high power klystron amplifiers, each capable of delivering 500 kW rf power. In this article, the results obtained during installation and commissioning of these klystrons are presented. Two klystrons (model TH2103D) have been successfully installed and commissioned on dummy loads, delivering ˜200 kW power for more than 1000 s. The maximum output power that could be obtained is limited due to the available direct current (dc) power supply. The test system is comprised of a TH2103D klystron, a low power rf (3.7 GHz/25 W) source, two high power four port circulators, two high power dual directional couplers, two arc detector systems, and two dummy water loads. To avoid rf breakdown in the rf components of the transmission line, the system has been pressurized with dry air to 3 bar. To energize and operate the klystron, a high voltage dc power supply, a magnet power supply, an ion pump power supply, a -65 kV floating anode modulator power supply, and a filament power supply are used. An arc detector unit has been installed to detect and initiate action within a few microseconds to protect the klystron, waveguides, and other rf passive components during arcing. To protect the klystron in the event of an arc, a fast responding (<10 ?s), rail gap based pressurized crowbar unit has been used. The entire system is water cooled to avoid excess temperature rise during high power continuous wave operation of the klystron and other rf components. The tube requires initial conditioning. Thereafter, the output rf power is studied as a function of beam parameters such as cathode voltage and beam current.

  12. Designing and Managing Datacenters Powered by Renewable Energy

    E-print Network

    Designing and Managing Datacenters Powered by Renewable Energy ´I~nigo Goiri, William Katsak, Kien,wkatsak,lekien,tdnguyen,ricardob}@cs.rutgers.edu Abstract On-site renewable energy has the potential to reduce data- centers' carbon footprint and power/energy" datacenters, i.e. datacenters partially or completely powered by renewables such as solar or wind energy

  13. Simulation of High Power ICRF Wave Heating in the ITER Burning Plasma

    NASA Astrophysics Data System (ADS)

    Jaeger, E. F.; Berry, L. A.; Barrett, R. F.; D'Azevedo, E. F.

    2007-11-01

    ITER relies on Ion-cyclotron Radio Frequency (ICRF) power to heat the plasma to fusion temperatures. To heat effectively, the waves must couple efficiently to the core plasma. Recent simulations using AORSA [1] on the 120 TF Cray XT-4 (Jaguar) at ORNL show that the waves propagate radially inward and are rapidly absorbed with little heating of the plasma edge. AORSA has achieved 87.5 trillion calculations per second (87.5 teraflops) on Jaguar, which is 73 percent of the system's theoretical peak. Three dimensional visualizations show ``hot spots'' near the antenna surface where the wave amplitude is high. AORSA simulations are also being used to study how to best use ICRF to drive plasma currents for optimizing ITER performance and pulse length. Results for Scenario 4 show a maximum current of 0.54 MA for 20 MW of power at 57 MHz. [1] E.F. Jaeger, L.A. Berry, E. D'Azevedo, et al., Phys. Plasmas. 8, 1573 (2001).

  14. Thrust Generation with Low-Power Continuous-Wave Laser and Aluminum Foil Interaction

    SciTech Connect

    Horisawa, Hideyuki; Sumida, Sota; Funaki, Ikkoh

    2010-05-06

    The micro-newton thrust generation was observed through low-power continuous-wave laser and aluminum foil interaction without any remarkable ablation of the target surface. To evaluate the thrust characteristics, a torsion-balance thrust stand capable for the measurement of the thrust level down to micro-Newton ranges was developed. In the case of an aluminum foil target with 12.5 micrometer thickness, the maximum thrust level was 15 micro-newtons when the laser power was 20 W, or about 0.75 N/MW. It was also found that the laser intensity, or laser power per unit area, irradiated on the target was significantly important on the control of the thrust even under the low-intensity level.

  15. Waves

    E-print Network

    LaCure, Mari Mae

    2010-04-29

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

  16. Investigation of Wave Energy Converter Effects on Wave Fields: A Modeling Sensitivity Study in Monterey Bay CA.

    SciTech Connect

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

    2014-08-01

    A n indust ry standard wave modeling tool was utilized to investigate model sensitivity to input parameters and wave energy converter ( WEC ) array deploym ent 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 b oth wave height and near - bottom orbital velocity we re subject to the largest pote ntial variations, each decreas ed in sensitivity as transmission coefficient increase d , as number and spacing of WEC devices decrease d , and as the deployment location move d offshore. Wave direction wa s affected consistently for all parameters and wave perio d was not affected (or negligibly affected) by varying model parameters or WEC configuration .

  17. Influence of ambient air pressure on the energy conversion of laser-breakdown induced blast waves

    NASA Astrophysics Data System (ADS)

    Wang, Bin; Komurasaki, Kimiya; Arakawa, Yoshihiro

    2013-09-01

    Influence of ambient pressure on energy conversion efficiency from a Nd?:?glass laser pulse (? = 1.053 µm) to a laser-induced blast wave was investigated at reduced pressure. Temporal incident and transmission power histories were measured using sets of energy meters and photodetectors. A half-shadowgraph half-self-emission method was applied to visualize laser absorption waves. Results show that the blast energy conversion efficiency ?bw decreased monotonically with the decrease in ambient pressure. The decrease was small, from 40% to 38%, for the pressure change from 101 kPa to 50 kPa, but the decrease was considerable, to 24%, when the pressure was reduced to 30 kPa. Compared with a TEA-CO2-laser-induced blast wave (? = 10.6 µm), higher fraction absorption in the laser supported detonation regime ?LSD of 90% was observed, which is influenced slightly by the reduction of ambient pressure. The conversion fraction ?bw/?LSD?90% was achieved at pressure >50 kPa, which is significantly higher than that in a CO2 laser case.

  18. Simplified 2D modeling of power and energy transduction of piezoelectric wafer active sensors for structural health monitoring

    NASA Astrophysics Data System (ADS)

    Lin, Bin; Giurgiutiu, Victor

    2011-04-01

    This paper presents an investigation of 2-D power and energy transduction in piezoelectric wafer active sensors (PWAS) for structural health monitoring (SHM). After a literature review of the state of the art, we developed a model of 2-D power and energy transduction of PWAS attached to structure. The model is an extension of our previously presented 1-D model. It allows examination of power and energy flow for a circular crested wave pattern. The model assumptions include: (a) 2-D axial and flexural wave propagation; (b) ideal bonding (line-force) connection between PWAS and structure; (c) ideal excitation source at the transmitter PWAS and fully-resistive external load at the receiver PWAS (d) crested wave energy spread out. Wave propagation method for an infinite boundary plate, electromechanical energy transformation of PWAS and structure, and wave propagation energy spread out in 2-D plate were considered. The parametric study of PWAS size, impedance match gives the PWAS design guideline for PWAS sensing and power harvesting applications. In pitch-catch PWAS application, the frequency response functions of a circular PWAS are developed for voltage in consideration with the receiver capacitance and external resistive loads.

  19. On the concept of sloped motion for free-floating wave energy converters

    PubMed Central

    Payne, Grégory S.; Pascal, Rémy; Vaillant, Guillaume

    2015-01-01

    A free-floating wave energy converter (WEC) concept whose power take-off (PTO) system reacts against water inertia is investigated herein. The main focus is the impact of inclining the PTO direction on the system performance. The study is based on a numerical model whose formulation is first derived in detail. Hydrodynamics coefficients are obtained using the linear boundary element method package WAMIT. Verification of the model is provided prior to its use for a PTO parametric study and a multi-objective optimization based on a multi-linear regression method. It is found that inclining the direction of the PTO at around 50° to the vertical is highly beneficial for the WEC performance in that it provides a high capture width ratio over a broad region of the wave period range. PMID:26543397

  20. The sea surface currents as a potential factor in the estimation and monitoring of wave energy potential

    NASA Astrophysics Data System (ADS)

    Zodiatis, George; Galanis, George; Nikolaidis, Andreas; Stylianoy, Stavros; Liakatas, Aristotelis

    2015-04-01

    The use of wave energy as an alternative renewable is receiving attention the last years under the shadow of the economic crisis in Europe and in the light of the promising corresponding potential especially for countries with extended coastline. Monitoring and studying the corresponding resources is further supported by a number of critical advantages of wave energy compared to other renewable forms, like the reduced variability and the easier adaptation to the general grid, especially when is jointly approached with wind power. Within the framework, a number of countries worldwide have launched research and development projects and a significant number of corresponding studies have been presented the last decades. However, in most of them the impact of wave-sea surface currents interaction on the wave energy potential has not been taken into account neglecting in this way a factor of potential importance. The present work aims at filling this gap for a sea area with increased scientific and economic interest, the Eastern Mediterranean Sea. Based on a combination of high resolution numerical modeling approach with advanced statistical tools, a detailed analysis is proposed for the quantification of the impact of sea surface currents, which produced from downscaling the MyOcean-FO regional data, to wave energy potential. The results although spatially sensitive, as expected, prove beyond any doubt that the wave- sea surface currents interaction should be taken into account for similar resource analysis and site selection approaches since the percentage of impact to the available wave power may reach or even exceed 20% at selected areas.

  1. Using Auxiliary Gas Power for CCS Energy Needs in Retrofitted Coal Power Plants

    E-print Network

    1 Using Auxiliary Gas Power for CCS Energy Needs in Retrofitted Coal Power Plants by Sarah Bashadi and Policy Program #12;2 #12;3 Using Auxiliary Gas Power for CCS Energy Needs in Retrofitted Coal Power-combustion capture retrofits are expected to a near-term option for mitigating CO2 emissions from existing coal

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

    DOEpatents

    Caplan, Malcolm; Friedman, Herbert W.

    2005-07-19

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

  3. A study on pseudo interface wave technique for CRDM weld defects in nuclear power plants

    SciTech Connect

    Lee, Jaesun E-mail: jpp@pusan.ac.kr; Park, Junpil E-mail: jpp@pusan.ac.kr; Cho, Younho; Huh, Hyung E-mail: dokim@kaeri.re.kr; Park, Keun-Bae E-mail: dokim@kaeri.re.kr; Kim, Dong-Ok E-mail: dokim@kaeri.re.kr

    2015-03-31

    The nuclear power plant inspection is very important for the safety issue. However due to some radiation and geometric problems, the detection of CRDM(Control Rod Drive Mechanism) can be very difficult by using conventional Ultrasonic Testing method. Also the shrink fit boundary condition can also be an obstacle for the inspection in this paper, instead of conventional Ultrasonic Testing, guided wave was used for the detection of some complicated structures. The CRDM nozzle was installed in reactor head with perfect shrink fit condition by using stainless steel. The wave amplitude distribution on the circumferential direction was calculated with various boundary conditions and the experimental result shows a possibility of the defect detection on J-groove weld.

  4. A study on pseudo interface wave technique for CRDM weld defects in nuclear power plants

    NASA Astrophysics Data System (ADS)

    Lee, Jaesun; Park, Junpil; Cho, Younho; Huh, Hyung; Park, Keun-Bae; Kim, Dong-Ok

    2015-03-01

    The nuclear power plant inspection is very important for the safety issue. However due to some radiation and geometric problems, the detection of CRDM(Control Rod Drive Mechanism) can be very difficult by using conventional Ultrasonic Testing method. Also the shrink fit boundary condition can also be an obstacle for the inspection in this paper, instead of conventional Ultrasonic Testing, guided wave was used for the detection of some complicated structures. The CRDM nozzle was installed in reactor head with perfect shrink fit condition by using stainless steel. The wave amplitude distribution on the circumferential direction was calculated with various boundary conditions and the experimental result shows a possibility of the defect detection on J-groove weld.

  5. 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.

  6. 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..

  7. Initiation of reactive blast waves by external energy sources

    NASA Astrophysics Data System (ADS)

    Liñán, Amable; Kurdyumov, Vadim N.; Sánchez, Antonio L.

    2012-11-01

    This article is devoted to the analysis of the direct initiation, by concentrated centrally-symmetric external energy sources, of self-sustained detonation waves in gaseous reactive mixtures. The dynamics of the detonation front will be described in the fast reaction limit, when the thickness of the reaction layer that follows the shock front is very small compared with the shock radius. At early times, after starting the external thermal energy deposition, the detonation front, associated with a strongly expanding flow, is overdriven; thus it is reached by expansion waves that decrease its velocity towards the Chapman-Jouguet (CJ) value, for which the expansion waves can no longer reach the front. The decay occurs for detonation radii such that the energy released by the external source equals the heat released by the chemical reaction. For planar detonations the CJ velocity is only approached asymptotically for large times, while for cylindrical and spherical detonations the flow divergence provides an additional decay mechanism associated with the front curvature that causes the transition to the constant CJ velocity to occur at a finite value of the detonation radius. The time evolution of the flow field and the corresponding variation with deposition time of the transition radius is computed for energy sources of constant heating rate. The analysis includes a detailed quantitative description of the near-front flow structure for times close to the transition time, given here for the first time, along with the study of the evolution towards the Zel'dovich-Taylor cylindrical or spherical self-similar flow structure, which corresponds to a CJ detonation front ideally initiated at the center without any external energy source. The asymptotic decay to CJ is also described for planar detonations initiated with energy sources of constant heating rate and finite nonzero deposition time. A brief discussion will be given on how the reaction may be quenched by the flow divergence effects if the initiating energy is smaller than a critical value, thus failing to generate a self-propagating detonation wave.

  8. 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.

  9. Wave properties near the subsolar magnetopause - Pc 3-4 energy coupling for northward interplanetary magnetic field

    NASA Technical Reports Server (NTRS)

    Song, P.; Russell, C. T.; Strangeway, R. J.; Wygant, J. R.; Cattell, C. A.; Fitzenreiter, R. J.; Anderson, R. R.

    1993-01-01

    Strong slow mode waves in the Pc 3-4 frequency range are found in the magnetosheath close to the magnetopause. We have studied these waves at one of the ISEE subsolar magnetopause crossings using the magnetic field, electric field, and plasma measurements. We use the pressure balance at the magnetopause to calibrate the Fast Plasma Experiment data versus the magnetometer data. When we perform such a calibration and renormalization, we find that the slow mode structures are not in pressure balance and small scale fluctuations in the total pressure still remain in the Pc 3-4 range. Energy in the total pressure fluctuations can be transmitted through the magnetopause by boundary motions. The Poynting flux calculated from the electric and magnetic field measurements suggests that a net Poynting flux is transmitted into the magnetopause. The two independent measurements show a similar energy transmission coefficient. The transmitted energy flux is about 18 percent of the magnetic energy flux of the waves in the magnetosheath. Part of this transmitted energy is lost in the sheath transition layer before it enters the closed field line region. The waves reaching the boundary layer decay rapidly. Little wave power is transmitted into the magnetosphere.

  10. Traveling wave device for combining or splitting symmetric and asymmetric waves

    DOEpatents

    Möbius, Arnold (Eggenstein, DE); Ives, Robert Lawrence (Saratoga, CA)

    2005-07-19

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

  11. Model development on the dynamic of wave-current interaction and the implementation on the offshore wind power

    NASA Astrophysics Data System (ADS)

    Wu, Tso-Ren; Huang, Chin-Cheng; Lin, Chun-Wei; Chuang, Mei-Hui; Cheng, Che-Yu; Tsai, Yu-Lin

    2015-04-01

    In this study, we performed the three-dimensional numerical simulation and analysis for solving the dynamic loads from waves and currents on the offshore wind turbines. Scenarios focused on the extreme weather conditions. During the typhoon event, the wind-driven storm waves and currents have to be considered while solving the dynamic load on the structures. The Splash3D model was adopted to perform the simulation of the interaction between breaking waves and structures. The core of the Splash3D model is the Truchas model which was developed by Los Alamos National Laboratory (LANL) and featured as high accuracy. Splash3D is capable of solving the dynamic process for the interaction between the structure and fluids with complex breaking free-surface. This model is also able to simulate the local scour under the violent flow condition. In order to adequately simulate the waves under monsoon or typhoon, we developed a new wave generation module based on the dispersion relationship. This wave-maker module was used to generate regular waves, irregular waves, and breaking waves under the extreme weather condition. The module was used to simulate the synthetic effect under the effects of waves and currents for obtaining the force distribution on the foundation of the offshore wind turbine. Keyword: Splash3D, wind power, VOF, wave-current interaction, dynamic loads, wind turbines.

  12. Evanescent-wave fiber-optic sensor: on power transfer from core-cladding interface to fiber end-face

    NASA Astrophysics Data System (ADS)

    Chiniforooshan, Yasser; Ma, Jianjun; Bock, Wojtek J.

    2011-05-01

    In this paper, the enhancement of collection efficiency in fiber-optic evanescent-wave (EW) sensors is studied. Both theory and experimental results are presented. The theory is based primarily on ray optics, but for the sake of simplicity and accuracy, wave optics is also considered. Fluorescent light is coupled into the core of a partly unclad multimode fiber via EW. Most power is carried to the unclad end-face by tunneling modes. Reflection from this rough end-face, which is modeled as a diffuse source, mixes the initial modes. Bound rays also play an important role, carrying the power to the other end-face. The amount of output power of the bound rays there is calculated. We also study the output power when the end-face is smooth. The comparison of these two cases of output power shows that the rough end-face enhances the collection of coupled evanescent waves.

  13. Energy dissipation via electron energization in standing shear Alfven waves

    SciTech Connect

    Damiano, P. A.; Wright, A. N.; Sydora, R. D.; Samson, J. C.

    2007-06-15

    A two-dimensional hybrid magnetohydrodynamic-kinetic electron model in dipolar coordinates is used to study the case of a fundamental mode toroidal field line resonance (FLR) centered on an L=10 closed dipolar magnetic field line. The model is initialized via a perturbation of the azimuthal shear Alfven velocity so that only upward field aligned currents (corresponding to downwelling electrons) are present at the ionospheric boundaries during the first half wave period. It is found that the acceleration of the electrons to carry the field aligned currents can be a significant sink of Alfven wave energy depending on the width of the flux tube. For a FLR with an equatorial perpendicular wavelength of 0.25 R{sub E} about 20% of the wave energy is dissipated over a half cycle. This varies inversely with the width of the flux tube increasing to 40% by a width of 0.15 R{sub E}, which, unless the system is driven, can completely damp the resonance in about 2-3 cycles.

  14. Pulse energy evolution for high-resolution Lamb wave inspection

    NASA Astrophysics Data System (ADS)

    Hua, Jiadong; Lin, Jing; Zeng, Liang; Gao, Fei

    2015-06-01

    Generally, tone burst excitation methods are used to reduce the effect of dispersion in Lamb wave inspection. In addition, algorithms for dispersion compensation are required to simplify responses, especially in long-range inspection. However, the resolution is always limited by the time duration of tone burst excitation. A pulse energy evolution method is established to overcome this limitation. In this method, a broadband signal with a long time (e.g. a chirp, white noise signal, or a pseudo-random sequence) is used as excitation to actuate Lamb waves. First of all, pulse compression is employed to estimate system impulse response with a high signal-to-noise ratio. Then, dispersion compensation is applied repeatedly with systemically varied compensation distances, obtaining a series of compensated signals. In these signals, amplitude (or energy) evolution associated with the change of compensation distance is utilized to estimate the actual propagation distance of the interested wave packet. Finally, the defect position is detected by an imaging algorithm. Several experiments are given to validate the proposed method.

  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. Influence of wall plasma on microwave frequency and power in relativistic backward wave oscillator

    NASA Astrophysics Data System (ADS)

    Sun, Jun; Wu, Ping; Cao, Yibing; Teng, Yan; Zhang, Yuchuan; Chen, Changhua

    2015-07-01

    The RF breakdown of the slow wave structure (SWS), which will lead to the generation of the wall plasma, is an important cause for pulse shortening in relativistic backward wave oscillators. Although many researchers have performed profitable studies about this issue, the influence mechanism of this factor on the microwave generation still remains not-so-clear. This paper simplifies the wall plasma with an "effective" permittivity and researches its influence on the microwave frequency and power. The dispersion relation of the SWS demonstrates that the introduction of the wall plasma will move the dispersion curves upward to some extent, which is confirmed by particle-in-cell (PIC) simulations and experiments. The plasma density and volume mainly affect the dispersion relation at the upper and lower frequency limits of each mode, respectively. Meanwhile, PIC simulations show that even though no direct power absorption exists since the wall plasma is assumed to be static, the introduction of the wall plasma may also lead to the decrease in microwave power by changing the electrodynamic property of the SWS.

  17. Holocene reef development where wave energy reduces accommodation

    USGS Publications Warehouse

    Grossman, Eric E.; Fletcher, Charles H.

    2004-01-01

    Analyses of 32 drill cores obtained from the windward reef of Kailua Bay, Oahu, Hawaii, indicate that high wave energy significantly reduced accommodation space for reef development in the Holocene and produced variable architecture because of the combined influence of sea-level history and wave exposure over a complex antecedent topography. A paleostream valley within the late Pleistocene insular limestone shelf provided accommodation space for more than 11 m of vertical accretion since sea level flooded the bay 8000 yr BP. Virtually no net accretion (pile-up of fore-reef-derived rubble (rudstone) and sparse bindstone, and (3) a final stage of catch-up bindstone accretion in depths > 6 m. Coral framestone accreted at rates of 2.5-6.0 mm/yr in water depths > 11 m during the early Holocene; it abruptly terminated at ~4500 yr BP because of wave scour as sea level stabilized. More than 4 m of rudstone derived from the upper fore reef accreted at depths of 6 to 13 m below sea level between 4000 and 1500 yr BP coincident with late Holocene relative sea-level fall. Variations in the thickness, composition, and age of these reef facies across spatial scales of 10-1000 m within Kailua Bay illustrate the importance of antecedent topography and wave-related stress in reducing accommodation space for reef development set by sea level. Although accommodation space of 6 to 17 m has existed through most of the Holocene, the Kailua reef has been unable to catch up to sea level because of persistent high wave stress.

  18. Surface-emitting terahertz quantum cascade lasers with continuous-wave power in the tens of milliwatt range

    SciTech Connect

    Xu, Gangyi; Li, Lianhe; Giles Davies, A.; Linfield, Edmund H.; Isac, Nathalie; Halioua, Yacine; Colombelli, Raffaele

    2014-03-03

    We demonstrate efficient surface-emitting terahertz frequency quantum cascade lasers with continuous wave output powers of 20–25?mW at 15?K and maximum operating temperatures of 80–85?K. The devices employ a resonant-phonon depopulation active region design with injector, and surface emission is realized using resonators based on graded photonic heterostructures (GPHs). GPHs can be regarded as energy wells for photons and have recently been implemented through grading the period of the photonic structure. In this paper, we show that it is possible to keep the period constant and grade instead the lateral metal coverage across the GPH. This strategy ensures spectrally single-mode operation across the whole laser dynamic range and represents an additional degree of freedom in the design of confining potentials for photons.

  19. 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

  20. Power processing and active protection for photovoltaic energy extraction

    E-print Network

    Chang, 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 ...

  1. 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...

  2. Recent Advances in High Power Millimeter Wave Gyroklystron Amplifiers at NRL

    NASA Astrophysics Data System (ADS)

    Danly, B. G.

    1998-04-01

    Amplifiers based on the electron cyclotron resonance maser or gyrotron interaction are capable of producing both high peak and high average powers in the millimeter wave band. These devices are of interest for a variety of applications including use in millimeter wave radars and as drivers for high frequency RF accelerators. Recent progress on 35 GHz and 93 GHz gyroklystron and gyrotwystron amplifiers in the Vacuum Electronics Branch of the Naval Research Laboratory will be described. At 35 GHz, a two-cavity device has produced up to 210 kW peak power at 37% efficiency with limited bandwidth( J.J. Choi, A.H. McCurdy, F. Wood, R.H. Kyser, J. Calame, K. Nguyen, B.G. Danly, T.M. Antonsen Jr., B. Levush, and R.K. Parker, Experimental Investigation of a High Power, Two-Cavity, 35 GHz Gyroklystron Amplifier IEEE Trans.Plasma Sci., To Be Published, 1998.), and a three-cavity device has produced up to 225 kW peak power with 0.6% bandwidth. At 93 GHz, successive experimental four-cavity gyroklystrons have produced up to 67 kW with 460 MHz bandwidth and 60 kW with 640 MHz bandwidth(M. Blank, B.G. Danly, B. Levush, P.E. Latham, and D. Pershing, Experimental Demonstration of a W-Band Gyroklystron Amplifier Phys.Rev.Lett., vol. 79, pp. 4485-4488, 1997.). These amplifiers have had gains in the 27 - 30 dB range. The experimental results are in excellent agreement with theoretical predictions. Recent progress will be detailed, and opportunities for higher power and bandwidth will be discussed.

  3. Compressed air producing, tidal and wave-power collection apparatus for installation in large bodies of water

    SciTech Connect

    Eberle, W.J.

    1980-06-10

    A novel tidal and wave-power collection apparatus is disclosed which is well suited for oceanic installations. In the preferred embodiment, a matrix of power collection units is easily assembled at sea, each being bridged and reinforced by catwalks extending therebetween which form trilateral power collection modules having such units at each of the corners thereof. Each power collection unit comprises a central tubular pilaster embedded in the ocean floor around which is disposed a toroidal float which moves up and down with the waves and tide and which acts to drive an air compressor while rising and falling. The output of the air compressor, I.E. Compressed air, is stored in the float's chamber and is transmitted through conduits in the bridging structure to a remote power consumption site. The apparatus is efficient, economical and capable of capturing and storing large quantities of power which may be utilized to satisfy peak load power demands.

  4. High power and high temperature continuous-wave operation of distributed Bragg reflector quantum cascade lasers

    SciTech Connect

    Xie, Feng Caneau, Catherine G.; LeBlanc, Herve P.; Ho, Ming-tsung; Wang, Jie; Chaparala, Satish; Hughes, Lawrence C.; Zah, Chung-en

    2014-02-17

    High temperature continuous-wave (CW) operation of a distributed Bragg reflector (DBR) quantum cascade laser is demonstrated up to a heat sink temperature of 80?°C. A CW output power of 2?W and a single mode operation with side mode suppression ratio of 30 dB around wavelength of 4.48??m were achieved at 20?°C. The maximum pulsed and CW wall-plug-efficiencies reached 14.7% and 10.3% at 20?°C, respectively. A large tuning range of 5?cm{sup ?1} between mode hopping was observed and attributed to the thermal cross-talk from the gain section to the DBR section.

  5. Observations of E region irregularities generated at auroral latitudes by a high-power radio wave

    NASA Technical Reports Server (NTRS)

    Djuth, F. T.; Jost, R. J.; Noble, S. T.; Gordon, W. E.; Stubbe, P.

    1985-01-01

    The initial results of a series of observations made with the high-power HF heating facility near Tromso, Norway are reported. During these experiments, attention was focused on the production of artificial geomagnetic field-aligned irregularities (AFAIs) in the auroral E region by HF waves. A mobile 46.9-MHz radar was used to diagnose the formation of AFAIs having spatial scales of 3.2 across geomagnetic field lines. The dynamic characteristics of the AFAIs are discussed within the context of current theoretical work dealing with the natural production of AFAIs in the ionosphere.

  6. Intense shock waves in hot dense matter generated by high-power light ion beams

    SciTech Connect

    Fortov, V.; Kanel, G.; Utkin, A.; Vorobiev, O.

    1996-05-01

    Response of plane targets to the high-power proton beam has been investigated using time-resolved laser Doppler velocimetry with sub-nanosecond temporal resolution. Experiments have been performed at Karlsruhe Light Ion Facility (KALIF). Results of measurements are free-surface velocity profiles of metal foils accelerated by the ablative pressure. An acoustic model was employed for a semi-quantitative interpretation of the initial phase of wave generation. Numerical simulation of foil accelerations have been performed to validate wide-rage EOS models for the region of a dense strongly coupled plasma. {copyright} {ital 1996 American Institute of Physics.}

  7. Experimental determination of radiated internal wave power without pressure field data Frank M. Lee, M. S. Paoletti, Harry L. Swinney, and P. J. Morrison

    E-print Network

    Experimental determination of radiated internal wave power without pressure field data Frank M. Lee Articles you may be interested in Internal wave and boundary current generation by tidal flow over) Experimental determination of radiated internal wave power without pressure field data Frank M. Lee,1 M. S

  8. 1. We can hear around corners, but we cannot see around corners. The reason is that a) Sound waves carry more energy than do light waves

    E-print Network

    Coleman, Piers

    1. We can hear around corners, but we cannot see around corners. The reason is that a) Sound waves carry more energy than do light waves b) The frequency of sound is much greater than that of light c) The wavelength of sound is much greater than that of light d) Sound waves are longitudinal, while light waves

  9. Wave energies and wave-induced longshore currents in an unstructured-grid model - circulation in front of barrier islands

    NASA Astrophysics Data System (ADS)

    Jörg-Olaf Wolff, , Prof. _., Dr.; Grashorn, Sebastian, , Dr.; Lettmann, Karsten A., , Dr.; Badewien, Thomas H., , Dr.; Stanev, Emil V., Prof. _., Dr.

    2015-04-01

    An unstructured-grid model (FVCOM) coupled to a wave model (FVCOM-SWAVE) is used to investigate the hydrodynamic and wave energy conditions during a moderate and a storm situation in the southern North Sea. Two different setups are presented. One setup covers the whole North Sea with moderately increased grid resolution at the coast, whereas the other comprises a very high resolution East Frisian Wadden Sea setup, one-way coupled to the coarser North Sea model. The results of both model setups are validated, compared to each other and analysed with a focus on longshore currents and wave energy. The results show that during storm conditions strong wave-induced longshore currents occur in front of the barrier islands of the East Frisian Wadden Sea, resulting in total current speeds up to 2 m/s. This effect is especially pronounced in the high-resolution setup. The wave-current interaction also influences the sea surface elevation by raising the water level in the tidal basins. Calculated wave energies show large differences between moderate wind and storm conditions with time-averaged values up to 200 kW/m. The numerical results indicate that wave-current coupling, albeit numerically expensive, cannot be ignored because it plays an important role in almost all near coastal transport phenomena (sediments, contaminants, bacteria, etc.).

  10. Renewable Energy Penetration on the power Grid Fall / 2010

    E-print Network

    Stuart, Steven J.

    ECE 420 Renewable Energy Penetration on the power Grid Fall / 2010 Instructor: Dr. E. B. Makram: TBA Text: Renewable Energy Systems M. Godoy Simoes and Felix A. Farret Attendance: Test attendance): Principles of Renewable Sources of Energy and Electric Power: basic definitions of electrical power

  11. Dynamics of nonlinear snap--through chains with application to energy harvesting and wave propagation

    NASA Astrophysics Data System (ADS)

    Panigrahi, Smruti Ranjan

    There is much current research interest in nonlinear structures, smart materials, and metamaterials, that incorporate bistable, or snap-through, structural elements. Various applications include energy harvesting, energy dissipation, vibration absorption, vibration isolation, targeted energy transfer, bandgap design and metamaterials. In this dissertation, we explore snap-through structures with nonlinearity and negative linear stiffness. We start with a study of a simple Duffing oscillator with snap-through orbits around the separatrix. Multi-degree-of-freedom snap-through structures are known to convert the low-frequency inputs into high-frequency oscillations, and are called twinkling oscillators. A generalized two-degree-of-freedom (2-DOF) snap-through oscillator is shown to have rich bifurcation structure. The steady-state bifurcation analysis uncovered two unique bifurcations "star" and "eclipse" bifurcations, named due to their structures. The 2-DOF twinkler exhibits transient chaos in the snap-through regime. A fractal basin boundary study provides insight into the regions in the parameter space where the total energy level is predictable in an unsymmetric twinkler. Due to its capacity to convert low frequency to high-frequency oscillations, the snap-through oscillators can be used to harvest energy from low-frequency vibration sources. This idea has led us to explore the energy harvesting capacity of twinkling oscillators. Using magnets and linear springs we built (in collaboration with researchers at Duke university) novel experimental twinkling oscillators (SDOF and 2-DOF) for energy harvesting. When the magnets exhibit high-frequency oscillations through the inducting coil, a current is generated in the coil. This experiment shows promising results both for the SDOF and the 2-DOF twinkling energy generators by validating the frequency up-conversion and generating power from the low-frequency input oscillations. The experimental twinkling oscillator converted a 0.1 Hz input oscillation into 2.5 Hz output oscillation, a 25 times frequency up-conversion. The second part of this dissertation focuses on the dispersive nature of the waves in one dimensional nonlinear chains with weak nonlinearity. For metamaterial design, it is important to study the wave dispersion properties in the material for channeling energy in a desired direction or to build frequency-selective materials. In nonlinear structures there are various design parameters that can be tuned to produce desirable properties. The motivation of the wave propagation analysis is to understand the quadratic and cubic nonlinearity effects on the wave propagation behavior in an uniform periodic chain. Here the dispersion properties are studied through a multiple-scales perturbation approach for weakly nonlinear periodic media. Wave speed, cut-off frequencies, and wave-wave interaction characteristics are presented. The results show significant effect of quadratic nonlinearities in the dispersion characteristics of the waves in the chain.

  12. Momentum and energy transport by waves in the solar atmosphere and solar wind

    NASA Technical Reports Server (NTRS)

    Jacques, S. A.

    1977-01-01

    The fluid equations for the solar wind are presented in a form which includes the momentum and energy flux of waves in a general and consistent way. The concept of conservation of wave action is introduced and is used to derive expressions for the wave energy density as a function of heliocentric distance. The explicit form of the terms due to waves in both the momentum and energy equations are given for radially propagating acoustic, Alfven, and fast mode waves. The effect of waves as a source of momentum is explored by examining the critical points of the momentum equation for isothermal spherically symmetric flow. We find that the principal effect of waves on the solutions is to bring the critical point closer to the sun's surface and to increase the Mach number at the critical point. When a simple model of dissipation is included for acoustic waves, in some cases there are multiple critical points.

  13. 2/1/2014 geddem.com Wave Your iPhone for Power (Carefully): Micro-Windmill Technology http://www.geddem.com/2014/01/15/wave-your-iphone-for-power-carefully-micro-windmill-technology/ 1/3

    E-print Network

    Chiao, Jung-Chih

    2/1/2014 geddem.com » Wave Your iPhone for Power (Carefully): Micro-Windmill Technology http://www.geddem.com/2014/01/15/wave-your-iphone-for-power-carefully-micro-windmill-technology/ 1/3 Search here Subscribe (300) Tech (150) Gaming (5) Websites (23) Wave Your iPhone for Power (Carefully): Micro-Windmill

  14. Review of radio wave for power transmission in medical applications with safety

    NASA Astrophysics Data System (ADS)

    Day, John; Geddis, Demetris; Kim, Jaehwan; Choi, Sang H.; Yoon, Hargsoon; Song, Kyo D.

    2015-04-01

    The integration of biosensors with radio frequency (RF) wireless power transmission devices is becoming popular, but there are challenges for implantable devices in medical applications. Integration and at the same time miniaturization of medical devices in a single embodiment are not trivial. The research reported herein, seeks to review possible effects of RF signals ranging from 900 MHz to 100 GHz on the human tissues and environment. Preliminary evaluation shows that radio waves selected for test have substantial influence on human tissues based on their dielectric properties. In the advancement of RF based biosensors, it is imperative to set up necessary guidelines that specify how to use RF power safely. In this paper, the dielectric properties of various human tissues will be used for estimation of influence within the selected RF frequency ranges.

  15. High-harmonic fast-wave power flow along magnetic field lines in the scrape-off layer of NSTX.

    PubMed

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

    2012-07-27

    A significant fraction of high-harmonic fast-wave (HHFW) power applied to NSTX can be lost to the scrape-off layer (SOL) and deposited in bright and hot spirals on the divertor rather than in the core plasma. We show that the HHFW power flows to these spirals along magnetic field lines passing through the SOL in front of the antenna, implying that the HHFW power couples across the entire width of the SOL rather than mostly at the antenna face. This result will help guide future efforts to understand and minimize these edge losses in order to maximize fast-wave heating and current drive. PMID:23006093

  16. Energy scaling of terahertz-wave parametric sources.

    PubMed

    Tang, Guanqi; Cong, Zhenhua; Qin, Zengguang; Zhang, Xingyu; Wang, Weitao; Wu, Dong; Li, Ning; Fu, Qiang; Lu, Qingming; Zhang, Shaojun

    2015-02-23

    Terahertz-wave parametric oscillators (TPOs) have advantages of room temperature operation, wide tunable range, narrow line-width, good coherence. They have also disadvantage of small pulse energy. In this paper, several factors preventing TPOs from generating high-energy THz pulses and the corresponding solutions are analyzed. A scheme to generate high-energy THz pulses by using the combination of a TPO and a Stokes-pulse-injected terahertz-wave parametric generator (spi-TPG) is proposed and demonstrated. A TPO is used as a source to generate a seed pulse for the surface-emitted spi-TPG. The time delay between the pump and Stokes pulses is adjusted to guarantee they have good temporal overlap. The pump pulses have a large pulse energy and a large beam size. The Stokes beam is enlarged to make its size be larger than the pump beam size to have a large effective interaction volume. The experimental results show that the generated THz pulse energy from the spi-TPG is 1.8 times as large as that obtained from the TPO for the same pumping pulse energy density of 0.90 J/cm(2) and the same pumping beam size of 3.0 mm. When the pumping beam sizes are 5.0 and 7.0 mm, the enhancement times are 3.7 and 7.5, respectively. The spi-TPG here is similar to a difference frequency generator; it can also be used as a Stokes pulse amplifier. PMID:25836452

  17. Virtualizing Power Cords by Wireless Power Transmission and Energy Harvesting

    E-print Network

    Tentzeris, Manos

    for the virtualization of power cords for electrical devices. The first approach is a new concept for routing electric existing wireless power transfer scheme, this method can deliver electric power over a wide range, there is a general need to remove the electrical cords from rooms at low cost. If the wireless communication

  18. Guided wave energy trapping to detect hidden multilayer delamination damage

    NASA Astrophysics Data System (ADS)

    Leckey, Cara A. C.; Seebo, Jeffrey P.

    2015-03-01

    Nondestructive Evaluation (NDE) and Structural Health Monitoring (SHM) simulation tools capable of modeling three-dimensional (3D) realistic energy-damage interactions are needed for aerospace composites. Current practice in NDE/SHM simulation for composites commonly involves over-simplification of the material parameters and/or a simplified two-dimensional (2D) approach. The unique damage types that occur in composite materials (delamination, microcracking, etc) develop as complex 3D geometry features. This paper discusses the application of 3D custom ultrasonic simulation tools to study wave interaction with multilayer delamination damage in carbon-fiber reinforced polymer (CFRP) composites. In particular, simulation based studies of ultrasonic guided wave energy trapping due to multilayer delamination damage were performed. The simulation results show changes in energy trapping at the composite surface as additional delaminations are added through the composite thickness. The results demonstrate a potential approach for identifying the presence of hidden multilayer delamination damage in applications where only single-sided access to a component is available. The paper also describes recent advancements in optimizing the custom ultrasonic simulation code for increases in computation speed.

  19. PARTICLE ENERGY SPECTRA AT TRAVELING INTERPLANETARY SHOCK WAVES

    SciTech Connect

    Reames, Donald V.

    2012-09-20

    We have searched for evidence of significant shock acceleration of He ions of {approx}1-10 MeV amu{sup -1} in situ at 258 interplanetary traveling shock waves observed by the Wind spacecraft. We find that the probability of observing significant acceleration, and the particle intensity observed, depends strongly upon the shock speed and less strongly upon the shock compression ratio. For most of the 39 fast shocks with significant acceleration, the observed spectral index agrees with either that calculated from the shock compression ratio or with the spectral index of the upstream background, when the latter spectrum is harder, as expected from diffusive shock theory. In many events the spectra are observed to roll downward at higher energies, as expected from Ellison-Ramaty and from Lee shock-acceleration theories. The dearth of acceleration at {approx}85% of the shocks is explained by (1) a low shock speed, (2) a low shock compression ratio, and (3) a low value of the shock-normal angle with the magnetic field, which may cause the energy spectra that roll downward at energies below our observational threshold. Quasi-parallel shock waves are rarely able to produce measurable acceleration at 1 AU. The dependence of intensity on shock speed, seen here at local shocks, mirrors the dependence found previously for the peak intensities in large solar energetic-particle events upon speeds of the associated coronal mass ejections which drive the shocks.

  20. 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

    Ocean energy conversion has been of interest for many years. Recent developments such as concern over global warming have renewed interest in the topic. Part II provides an overview of the energy density found in ocean waves and how it is calculated...

  1. Energy flux of Alfven waves in weakly ionized plasma

    E-print Network

    J. Vranjes; S. Poedts; B. P. Pandey; B. De Pontieu

    2008-05-29

    The overshooting convective motions in the solar photosphere are frequently proposed as the source for the excitation of Alfv\\'en waves. However, the photosphere is a) very weakly ionized, and, b) the dynamics of the plasma particles in this region is heavily influenced by the plasma-neutral collisions. The purpose of this work is to check the consequences of these two facts on the above scenario and their effects on the electromagnetic waves. It is shown that the ions and electrons in the photosphere are both un-magnetized; their collision frequency with neutrals is much larger than the gyro-frequency. This implies that eventual Alfv\\'en-type electromagnetic perturbations must involve the neutrals as well. This has the following serious consequences: i) in the presence of perturbations, the whole fluid (plasma + neutrals) moves; ii) the Alfv\\'en velocity includes the total (plasma + neutrals) density and is thus considerably smaller compared to the collision-less case; iii) the perturbed velocity of a unit volume, which now includes both plasma and neutrals, becomes much smaller compared to the ideal (collision-less) case; and iv) the corresponding wave energy flux for the given parameters becomes much smaller compared to the ideal case.

  2. THE SLOW-MODE NATURE OF COMPRESSIBLE WAVE POWER IN SOLAR WIND TURBULENCE

    SciTech Connect

    Howes, G. G.; Klein, K. G.; TenBarge, J. M.; Bale, S. D.; Chen, C. H. K.; Salem, C. S.

    2012-07-01

    We use a large, statistical set of measurements from the Wind spacecraft at 1 AU, and supporting synthetic spacecraft data based on kinetic plasma theory, to show that the compressible component of inertial range solar wind turbulence is primarily in the kinetic slow mode. The zero-lag cross-correlation C({delta}n, {delta}B{sub ||}) between proton density fluctuations {delta}n and the field-aligned (compressible) component of the magnetic field {delta}B{sub ||} is negative and close to -1. The typical dependence of C({delta}n, {delta}B{sub ||}) on the ion plasma beta {beta}{sub i} is consistent with a spectrum of compressible wave energy that is almost entirely in the kinetic slow mode. This has important implications for both the nature of the density fluctuation spectrum and for the cascade of kinetic turbulence to short wavelengths, favoring evolution to the kinetic Alfven wave mode rather than the (fast) whistler mode.

  3. 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.

  4. PHYSICAL REVIEW E 86, 046204 (2012) Impedance and power fluctuations in linear chains of coupled wave chaotic cavities

    E-print Network

    Anlage, Steven

    2012-01-01

    wave chaotic cavities Gabriele Gradoni,* Thomas M. Antonsen, Jr., and Edward Ott Institute for Research of electromagnetic wave energy through a chain of coupled cavities is considered. The cavities are assumed to be of sufficiently irregular shape that their eigenmodes are described by random matrix theory. The cavities

  5. Electrical power distribution control methods, electrical energy demand monitoring methods, and power management devices

    DOEpatents

    Chassin, David P. (Pasco, WA); Donnelly, Matthew K. (Kennewick, WA); Dagle, Jeffery E. (Richland, WA)

    2011-12-06

    Electrical power distribution control methods, electrical energy demand monitoring methods, and power management devices are described. In one aspect, an electrical power distribution control method includes providing electrical energy from an electrical power distribution system, applying the electrical energy to a load, providing a plurality of different values for a threshold at a plurality of moments in time and corresponding to an electrical characteristic of the electrical energy, and adjusting an amount of the electrical energy applied to the load responsive to an electrical characteristic of the electrical energy triggering one of the values of the threshold at the respective moment in time.

  6. Electrical power distribution control methods, electrical energy demand monitoring methods, and power management devices

    DOEpatents

    Chassin, David P. (Pasco, WA); Donnelly, Matthew K. (Kennewick, WA); Dagle, Jeffery E. (Richland, WA)

    2006-12-12

    Electrical power distribution control methods, electrical energy demand monitoring methods, and power management devices are described. In one aspect, an electrical power distribution control method includes providing electrical energy from an electrical power distribution system, applying the electrical energy to a load, providing a plurality of different values for a threshold at a plurality of moments in time and corresponding to an electrical characteristic of the electrical energy, and adjusting an amount of the electrical energy applied to the load responsive to an electrical characteristic of the electrical energy triggering one of the values of the threshold at the respective moment in time.

  7. Modelling a point absorbing wave energy converter by the equivalent electric circuit theory: A feasibility study

    NASA Astrophysics Data System (ADS)

    Hai, Ling; Svensson, Olle; Isberg, Jan; Leijon, Mats

    2015-04-01

    There is a need to have a reliable tool to quickly assess wave energy converters (WECs). This paper explores whether it is possible to apply the equivalent electric circuit theory as an evaluation tool for point absorbing WEC system modelling. The circuits were developed starting from the force analysis, in which the hydrodynamic, mechanical, and electrical parameters were expressed by electrical components. A methodology on how to determine the parameters for electrical components has been explained. It is found that by using a multimeter, forces in the connection line and the absorbed electric power can be simulated and read directly from the electric circuit model. Finally, the circuit model has been validated against the full scale offshore experiment. The results indicated that the captured power could be predicted rather accurately and the line force could be estimated accurately near the designed working condition of the WEC.

  8. Momentum and Energy Transport by Gravity Waves in Stochastically Driven Stratified Flows. Part II: Radiation of Gravity Waves from a Gaussian Jet

    E-print Network

    Farrell, Brian F.

    Momentum and Energy Transport by Gravity Waves in Stochastically Driven Stratified Flows. Part II structures that dominate wave momentum and energy transport. When the interior of a typical midlatitude jet is stochastically forced, waves with short horizontal wavelength are trapped inside the jet and deposit momentum

  9. 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.

  10. 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.

  11. 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, the "Gardner free energy." Here, the plasma is rearranged incompressibly in the six- dimensional phase space of the plasma kinetic energy. In many cases of interest, the primary effect of the wave is to cause plasma

  12. Could energy intensive industries be powered by carbonfree electricity?

    E-print Network

    MacKay, David J.C.

    these requirements in the context of the decarbonization of the whole energy system using wind, biomass, solar power on energy neglects the fact that some of the fossil fuels used by industry deliver not only energy but alsoCould energy intensive industries be powered by carbon­free electricity? By David J C MacKay FRS

  13. Optimization Decomposition of Resistive Power Networks with Energy Storage

    E-print Network

    Tan, Chee Wei

    Optimization Decomposition of Resistive Power Networks with Energy Storage Xin Lou, Student Member with large-scale energy storage integration? With energy storage, there is a possibility to generate more flow problem with energy storage dynamics in purely resistive power networks. By exploiting a recently

  14. Power quality enhancement of renewable energy source power network using SMES system

    NASA Astrophysics Data System (ADS)

    Seo, H. R.; Kim, A. R.; Park, M.; Yu, I. K.

    2011-11-01

    This paper deals with power quality enhancement of renewable energy source power network using SMES system and describes the operation characteristics of HTS SMES system using real-toroidal-type SMES coil for smoothening the fluctuation of large-scale renewable energy source such as photovoltaic (PV) power generation system. It generates maximum power of PV array under various weather conditions. SMES unit charges and discharges the HTS coil to mitigate the fluctuation of PV system output power. The SMES unit is controlled according to the PV array output and the utility power quality conditions. The grid connected PV and SMES system has been modeled and simulated using power-hard-in-the-loop simulation (PHILS). The PHILS results demonstrated the effectiveness of the SMES system for enhancing power quality in power network including large-scale renewable energy source, especially PV power generation system.

  15. Sea ice floes dissipate the energy of steep ocean waves

    E-print Network

    Toffoli, Alessandro; Meylan, Michael H; Cavaliere, Claudio; Alberello, Alberto; Elsnab, John; Monty, Jason P

    2015-01-01

    Wave attenuation by ice floes is an important parameter for modelling the Arctic Oceans. At present, attenuation coefficients are extracted from linear models as a function of the incident wave period and floe thickness. Recent explorations in the Antarctic Mixed Ice Zone (MIZ) revealed a further dependence on wave amplitude, suggesting that nonlinear contributions are non-negligible. An experimental model for wave attenuation by a single ice floe in a wave flume is here presented. Observations are compared with linear predictions based on wave scattering. Results indicate that linear models perform well under the effect of gently sloping waves. For more energetic wave fields, however, transmitted wave height is normally over predicted. Deviations from linearity appear to be related to an enhancement of wave dissipation induced by unaccounted wave-ice interaction processes, including the floe over wash.

  16. Internal wave energy radiated from a turbulent mixed layer James R. Munroe1, a)

    E-print Network

    Sutherland, Bruce

    Internal wave energy radiated from a turbulent mixed layer James R. Munroe1, a) and Bruce R examine mixed-layer deepening and the generation of internal waves in stratified fluid resulting from. The internal waves are measured using synthetic schlieren to determine their amplitudes, frequencies

  17. ENERGY EFFICIENT MILLIMETER WAVE RADIO LINK ESTABLISHMENT WITH SMART ARRAY ANTENNAS

    E-print Network

    Baras, John S.

    1 ENERGY EFFICIENT MILLIMETER WAVE RADIO LINK ESTABLISHMENT WITH SMART ARRAY ANTENNAS Behnam of two millimeter wave transceiver nodes A and B. We assume that each node is equipped with a circular. INTRODUCTION Millimeter wave technology is becoming increasingly important in many military and commercial

  18. field fabricated solar powered steam turbinesfield fabricated solar powered steam turbines energy and computationenergy and computation

    E-print Network

    field fabricated solar powered steam turbinesfield fabricated solar powered steam turbines energy a turbineconverting solar power to mechanical energy using a turbine #12;a steam planta steam plant #12;focusing solar boiler #12;making steam with a boilermaking steam with a boiler #12;turbines can be pretty

  19. The energy balance of wind waves and the remote sensing problem

    NASA Technical Reports Server (NTRS)

    Hasselmann, K.

    1972-01-01

    Measurements of wave growth indicate an energy balance of the wave spectrum governed primarily by input from the atmosphere, nonlinear transfer to shorter and longer waves, and advection. The pronounced spectral peak and sharp low frequency cut-off characteristic of fetch-limited spectra are explained as a self-stabilizing feature of the nonlinear wave-wave interactions. The momentum transferred from the atmosphere to the wind waves accounts for a large part of the wind drag. These findings are relevant for remote microwave sensing of the sea surface by backscatter and passive radiometry methods.

  20. Relationship between wave energy and free energy from pickup ions in the Comet Halley environment

    NASA Technical Reports Server (NTRS)

    Huddleston, D. E.; Johnstone, A. D.

    1992-01-01

    The free energy available from the implanted heavy ion population at Comet Halley is calculated by assuming that the initial unstable velocity space ring distribution of the ions evolves toward a bispherical shell. Ultimately this free energy adds to the turbulence in the solar wind. Upstream and downstream free energies are obtained separately for the conditions observed along the Giotto spacecraft trajectory. The results indicate that the waves are mostly upstream propagating in the solar wind frame. The total free energy density always exceeds the measured wave energy density because, as expected in the nonlinear process of ion scattering, the available energy is not all immediately released. An estimate of the amount which has been released can be obtained from the measured oxygen ion distributions and again it exceeds that observed. The theoretical analysis is extended to calculate the k spectrum of the cometary-ion-generated turbulence.

  1. The mass, energy, space and time systemic theory-MEST-energy balance system of wave-particle duality

    NASA Astrophysics Data System (ADS)

    Cao, Dayong

    2011-03-01

    The paper suppose that the probability of displacement is the space and the probability of cycle is the time. And accroding to the quantum mechanics, the paper get the equation of the space : S = P (r) =f2 , (1) Among it, S: the space, f: the amplitude of wave, r: the displacement, P(r): probability function of displacement. Accroding to the Benford's law, the paper get the equation of the time equation: T = P (2 ?t) = ln (1 +1/2 ?t ) = ? , (2) Among it, T: the real time, t: date of clock, ? : the frequence of wave, P(t): probability function of date of the clock. E = h? , (3) m =h/?c , (4) Among it, E: the energy of particle, m: the mass of particle, c: the velocity of particle, ? : the frequence of particle, ? : the wavelengh, h: the Planck constant. E ' ? = i??/? ? t , (5) m ' ? = - i??/? ? t (? x)2 , (6) Among it, E ' ? : the energy of wave, m ' ? : the mass of wave, c ' : the velocity of wave, ? : the Wave Functions. The paper give new idea that unlike mass repel each other, like mass attract; And like energy repel each other, unlike energy attract. So there is a mass-energy duality too. The energy radiate the repulsive (energy) wave and the mass absorb the absorptive (mass) wave. And there is a balance system between the energy wave and mass wave. E + E ' ? =mc2 + m ' ?c '2 , (c '2 = -(?/x)2 (? t)2 ) , (7)

  2. A hybrid wave propagation and statistical energy analysis on the mid-frequency vibration of built-up plate systems

    NASA Astrophysics Data System (ADS)

    Ma, Yongbin; Zhang, Yahui; Kennedy, David

    2015-09-01

    Based on the concept of the hybrid finite element (FE) analysis and statistical energy analysis (SEA), a new hybrid method is developed for the mid-frequency vibration of a system comprising rectangular thin plates. The wave propagation method based on symplectic analysis is used to describe the vibration of the deterministic plate component. By enforcing the displacement continuity and equilibrium of force at the connection interface, the dynamic coupling between the deterministic plate component and the statistical plate component described by SEA is established. Furthermore, the hybrid solution formulation for the mid-frequency vibration of the system built up by plates is proposed. The symplectic analytical wave describing the deterministic plate component eliminates the boundary condition limitation of the traditional analytical wave propagation method and overcomes the numerical instability of numerical wave propagation methods. Numerical examples compare results from the proposed method with those from the hybrid FE-SEA method and the Monte Carlo method. The comparison illustrates that the proposed method gives good predictions for the mid-frequency behavior of the system considered here with low computational time. In addition, a constant proportionality coefficient between the system coupling power and the energy difference between the plate components can be found, when external forces are applied at different locations on a line perpendicular to the wave propagation direction. Based on this finding, two fast solution techniques are developed for the energy response of the system, and are validated by numerical examples.

  3. A New High Resolution Wave Modeling System for Renewable Energy Applications in California and the Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Galanis, G. N.; Kafatos, M.; Chu, P. C.; Hatzopoulos, N.; Emmanouil, G.; Kallos, G. B.

    2014-12-01

    The use of integrated high accuracy wave systems is of critical importance today for applications on renewable energy assessment and monitoring, especially over offshore areas where the availability of credible, quality controlled corresponding observations is limited. In this work a new wave modeling system developed by the Hellenic Naval Academy and the University of Athens, Greece, the Center of Excellence in Earth Systems Modeling & Observations of Schmid College of Science in Chapman University, USA and the Naval Ocean and Analysis Laboratory of the US-Naval Postgraduate School, is presented. The new wave system has been based on WAM (ECMWF parallel version) model and focuses on parameters that directly or not affect the estimation of wave power potential in offshore and near shore areas. The results obtained are utilized for monitoring the wave energy potential over the California and Eastern Mediterranean coastline. A detailed statistical analysis based on classical and non-conventional measures provides a solid framework for the quantification of the results. Extreme values-cases posing potential threats for renewable energy parks and platforms are particularly analyzed.

  4. Energy Drinks and Food Bars: Power or Hype?

    MedlinePLUS

    ... Your Best Self Smart Snacking Losing Weight Safely Energy Drinks and Food Bars: Power or Hype? KidsHealth > ... Downsides Cutting Through the Hype The Buzz on Energy Foods Energy drinks and nutrition bars often make ...

  5. Underwater Noise from a Wave Energy Converter Is Unlikely to Affect Marine Mammals

    PubMed Central

    Tougaard, Jakob

    2015-01-01

    Underwater noise was recorded from the Wavestar wave energy converter; a full-scale hydraulic point absorber, placed on a jack-up rig on the Danish North Sea coast. Noise was recorded 25 m from the converter with an autonomous recording unit (10 Hz to 20 kHz bandwidth). Median sound pressure levels (Leq) in third-octave bands during operation of the converter were 106–109 dB re. 1 ?Pa in the range 125–250 Hz, 1–2 dB above ambient noise levels (statistically significant). Outside the range 125–250 Hz the noise from the converter was undetectable above the ambient noise. During start and stop of the converter a more powerful tone at 150 Hz (sound pressure level (Leq) 121–125 dB re 1 ?Pa) was easily detectable. This tone likely originated from the hydraulic pump which was used to lower the absorbers into the water and lift them out of the water at shutdown. Noise levels from the operating wave converter were so low that they would barely be audible to marine mammals and the likelihood of negative impact from the noise appears minimal. A likely explanation for the low noise emissions is the construction of the converter where all moving parts, except for the absorbers themselves, are placed above water on a jack-up rig. The results may thus not be directly transferable to other wave converter designs but do demonstrate that it is possible to harness wave energy without noise pollution to the marine environment. PMID:26148299

  6. Colonisation of fish and crabs of wave energy foundations and the effects of manufactured holes - a field experiment.

    PubMed

    Langhamer, Olivia; Wilhelmsson, Dan

    2009-10-01

    Several Western European countries are planning for a significant development of offshore renewable energy along the European Atlantic Ocean coast, including many thousands of wave energy devices and wind turbines. There is an increasing interest in articulating the added values of the creation of artificial hard bottom habitats through the construction of offshore renewable energy devices, for the benefit of fisheries management and conservation. The Lysekil Project is a test park for wave power located about 100 km north of Gothenburg at the Swedish west coast. A wave energy device consists of a linear wave power generator attached to a foundation on the seabed, and connected by a wire to a buoy at the surface. Our field experiment examined the function of wave energy foundations as artificial reefs. In addition, potentials for enhancing the abundance of associated fish and crustaceans through manufactured holes of the foundations were also investigated. Assemblages of mobile organisms were examined by visual censuses in July and August 2007, 3 months after deployment of the foundations. Results generally show low densities of mobile organisms, but a significantly higher abundance of fish and crabs on the foundations compared to surrounding soft bottoms. Further, while fish numbers were not influenced by increased habitat complexity (holes), it had a significantly positive effect on quantities of edible crab (Cancer pagurus), on average leading to an almost five-fold increase in densities of this species. Densities of spiny starfish (Marthasterias glacialis) were negatively affected by the presence of holes, potentially due to increased predator abundance (e.g. C. pagurus). These results suggest a species-specific response to enhanced habitat complexity. PMID:19560811

  7. Coupling of Neutral-Beam-Driven Compressional Alfvén Eigenmodes to Kinetic Alfvén Waves in NSTX Tokamak and Energy Channeling.

    PubMed

    Belova, E V; Gorelenkov, N N; Fredrickson, E D; Tritz, K; Crocker, N A

    2015-07-01

    An energy-channeling mechanism is proposed to explain flattening of the electron temperature profiles at a high beam power in the beam-heated National Spherical Torus Experiment (NSTX). Results of self-consistent simulations of neutral-beam-driven compressional Alfvén eigenmodes (CAEs) in NSTX are presented that demonstrate strong coupling of CAEs to kinetic Alfvén waves at the Alfvén resonance location. It is suggested that CAEs can channel energy from the beam ions to the location of the resonant mode conversion at the edge of the beam density profile, modifying the energy deposition profile. PMID:26182100

  8. High-power continuous wave green beam generation by use of simple linear cavity with side-pumped module

    NASA Astrophysics Data System (ADS)

    Zhang, Y. P.; Zhao, X. D.; Zhang, H. Y.; Meng, L. H.; Li, L.; Li, X. F.; Wang, P.; Yao, J. Q.

    2010-12-01

    High-power continuous wave green radiation has been generated by means of type-II phase-matched frequency doubling in a KTP crystal located in a simple linear cavity incorporating a diode side-pumped Nd:YAG laser module. The cavity was designed to make the fundamental beam radius at the KTP crystal smaller than that at the gain medium, as is required for obtaining large mode volume in Nd:YAG crystal and realizing efficient CW intracavity frequency doubling. Output power of 51.2 W is obtained in the experiment with a diode-to-green optical conversion efficiency of 10.3%. The M 2-parameters of the laser are measured at different output powers. For the output power of about 47 W, the power fluctuation is measured less than 1%. The experimental results show that the continuous wave green laser system using this simple linear cavity offers good laser performance and output stability.

  9. Power line characterization from an airborne data collection with a millimeter wave radar

    NASA Astrophysics Data System (ADS)

    Goshi, Darren S.; Bui, Long Q.

    2014-05-01

    Enhancing the operational safety of small, maneuverable rotorcraft has been a critical consideration in the development of next generation situational awareness sensor suites. From landing assistance to target detection and obstacle avoidance, millimeter wave radars have become the leading candidate for such solutions due to their ability to operate in degraded visual environments, whether it is weather, induced debris, or night conditions that must be dealt with. Power lines pose arguably the largest safety risk for helicopter operation due to their difficulty in detection and proper identification to support avoidance maneuvering, where even under perfect conditions they can be nearly invisible to the naked eye. The backscatter phenomenology from braided power lines has been well-studied and formulated in previous literature, albeit mainly in controlled laboratory settings or limited field trials. Subsequently, the ability to simply detect power lines at operational distances up to around 2 km has been demonstrated. In this work, an analysis is performed on the measureable characteristics of power lines captured in a representative operational environment for helicopters. The test location included a diverse set of power line configurations with surrounding ground and tower clutter, representing a realistic scenario. A radiometrically calibrated w-band real-beam FMCW sensor allows the study and estimation of target RCS, as well as evaluation against the developed theory. All analysis is performed on dynamically captured data from a helicopter, where platform dynamics and system stability also play a significant role in a processed result. Results from this work will aid the effective development of next generation situational awareness systems.

  10. Optical fiber evanescent wave adsorption sensors for high-temperature gas sensing in advanced coal-fired power plants

    SciTech Connect

    Buric, M.; Ohodnicky, P.; Duy, J.

    2012-01-01

    Modern advanced energy systems such as coal-fired power plants, gasifiers, or similar infrastructure present some of the most challenging harsh environments for sensors. The power industry would benefit from new, ultra-high temperature devices capable of surviving in hot and corrosive environments for embedded sensing at the highest value locations. For these applications, we are currently exploring optical fiber evanescent wave absorption spectroscopy (EWAS) based sensors consisting of high temperature core materials integrated with novel high temperature gas sensitive cladding materials. Mathematical simulations can be used to assist in sensor development efforts, and we describe a simulation code that assumes a single thick cladding layer with gas sensitive optical constants. Recent work has demonstrated that Au nanoparticle-incorporated metal oxides show a potentially useful response for high temperature optical gas sensing applications through the sensitivity of the localized surface plasmon resonance absorption peak to ambient atmospheric conditions. Hence, the simulation code has been applied to understand how such a response can be exploited in an optical fiber based EWAS sensor configuration. We demonstrate that interrogation can be used to optimize the sensing response in such materials.

  11. Constraining dark matter late-time energy injection: decays and p-wave annihilations

    SciTech Connect

    Diamanti, Roberta; Mena, Olga; Palomares-Ruiz, Sergio; Vincent, Aaron C.; Lopez-Honorez, Laura E-mail: llopezho@vub.ac.be E-mail: sergio.palomares.ruiz@ific.uv.es

    2014-02-01

    We use the latest cosmic microwave background (CMB) observations to provide updated constraints on the dark matter lifetime as well as on p-wave suppressed annihilation cross sections in the 1 MeV to 1 TeV mass range. In contrast to scenarios with an s-wave dominated annihilation cross section, which mainly affect the CMB close to the last scattering surface, signatures associated with these scenarios essentially appear at low redshifts (z?<50) when structure began to form, and thus manifest at lower multipoles in the CMB power spectrum. We use data from Planck, WMAP9, SPT and ACT, as well as Lyman–? measurements of the matter temperature at z ? 4 to set a 95% confidence level lower bound on the dark matter lifetime of ? 4 × 10{sup 25} s for m{sub ?} = 100 MeV. This bound becomes lower by an order of magnitude at m{sub ?} = 1 TeV due to inefficient energy deposition into the intergalactic medium. We also show that structure formation can enhance the effect of p-wave suppressed annihilation cross sections by many orders of magnitude with respect to the background cosmological rate, although even with this enhancement, CMB constraints are not yet strong enough to reach the thermal relic value of the cross section.

  12. High power mid-infrared continuous-wave optical parametric oscillator pumped by fiber lasers

    NASA Astrophysics Data System (ADS)

    Xu, Xiaojun; Li, Xiao; Liu, Lei; Shang, Yaping

    2015-02-01

    3~5?m mid-infrared laser has many important applications, such as gas detection, spectral analysis, remote sensing, medical treatment, and also in the military laser radar, infrared countermine, and so on. Optical parametric oscillator (OPO) is an efficient way to generate laser in this wavelength range, which has attracted the eyes of many people. In this paper, the recent development of mid-infrared OPO is overviewed. Meanwhile, detailed introduction on our recent work is given. Maximum idler output power of 34.2W at center wavelength of 3.35?m was obtained, to our knowledge, which is the new power record of the international public reporting for the continue-wave (CW) mid-infrared OPO. It is worth mentioning that the pump source, the quasi single-frequency (SF) narrow line width fiber laser, was also developed by our groups. According to the current status of research, some solutions is proposed in order to achieve higher power, narrower line width, and compact volume mid-infrared OPO in a wide tunable range.

  13. Study on high-power continuous-wave mid-infrared optical parametric oscillator

    NASA Astrophysics Data System (ADS)

    Li, Xiao; Xu, Xiaojun; Shang, Yaping; Wang, Hongyan; Liu, Lei

    2014-10-01

    3~5?m mid-infrared laser has many important applications, such as gas detection, spectral analysis, remote sensing, medical treatment, and also in the military laser radar, infrared countermine, and so on. Optical parametric oscillator (OPO) is an efficient way to generate laser in this wavelength range, which has attracted the eyes of many people. In this paper, the recent development of mid-infrared OPO is overviewed. Meanwhile, detailed introduction on our recent work is given. Maximum idler output power of 34.2W at center wavelength of 3.35?m was obtained, to our knowledge, which is the new power record of the international public reporting for the continue-wave (CW) mid-infrared OPO. It is worth mentioning that the pump source, the quasi single-frequency (SF) narrow line width fiber laser, was also developed by our groups. According to the current status of research, some solutions is proposed in order to achieve higher power, narrower line width, and compact volume mid-infrared OPO in a wide tunable range.

  14. Energy Provisioning and Operating Costs in Hybrid Solar Powered Infrastructure

    E-print Network

    Karakostas, George

    1 Energy Provisioning and Operating Costs in Hybrid Solar Powered Infrastructure Mohammad Sheikh the operating and capital expenditure costs of solar powered additions to infrastructure that is operated from the power grid. The capital expenditure (CAPEX) costs are those associated with provisioning the solar power

  15. Road to Inertial Fusion Energy Fusion Power Associates Meeting

    E-print Network

    . Crack is clear through 5 mm thick deck plate #12;Coal-fired and KrF laser fusion power power plants have-electron-beams-nrl-to-clean-up- nox-emissions-from-coal-power-plant NRL has a Cooperative Research and Development AgreementRoad to Inertial Fusion Energy Fusion Power Associates Meeting Washington DC 16 December 2014

  16. Experimental Testing and Model Validation for Ocean Wave Energy Harvesting Buoys

    E-print Network

    Grilli, Stéphan T.

    , convert wave motion into electricity, to allow operation under all weather conditions, while enabling harvesting buoy systems, using the heave motion of the buoys to produce useful electrical power. Two for large scale grid power applications, but rather for relatively low-power ocean sensor and communications

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

    SciTech Connect

    Perkins, Roy

    2013-06-21

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

  18. Estimation and Monitoring of Wind/Wave energy potential in the Eastern Mediterranean Sea

    NASA Astrophysics Data System (ADS)

    Zodiatis, George; Galanis, George; Galanis, George; Emmanouil, George; Emmanouil, George; Hayes, Dan; Nikolaidis, Andreas; Georgiou, Georgios; Kalogeri, Christina; Kallos, George

    2013-04-01

    ?he adaptation and use of innovative methodologies for the exploitation of renewable energy marine resources is one of the main issues today for the environmental science community. Within this framework, the exploitation of wind and wave energy potential for coastal and island states seems to be one of the promising solutions and highly interesting from research and technological point of view. In this work, the activities of two projects focusing on the study of wind/wave energy over the area of Eastern Mediterranean Sea are presented. The "Integrated High Resolution System for Monitoring and Quantifying the Wave Energy Potential in the EEZ of Cyprus" (Ewave project) focuses on the estimation, monitoring and forecasting of the wave energy potential over the Levantine Basin with special emphasis to the Exclusive Economical Zone of Cyprus, while the "Development and application of new mathematical and physical models for Monitoring the wind and Sea wave Energy Potential" (MOSEP project) is a platform for developing new mathematical algorithms for the estimation of the wave energy over the Aegean Sea. In both projects, high resolution digital atlases of sea wave/wind climatological characteristics and the distribution of the wind and wave energy potential are developed for the coastal and offshore areas of the East Mediterranean sea . Moreover, new models for the prediction and quantification of wave energy in short and long forecast horizons are proposed. Statistical results concerning the probability density functions of the wind speed, the significant wave height, as well as the energy potential will be presented for selected sea areas in the Eastern Mediterranean Sea, while test case studies in certain regions favor to wind/wave renewable energy will be discussed.

  19. Small-scale energy harvesting through thermoelectric, vibration, and radiofrequency power conversion

    NASA Astrophysics Data System (ADS)

    Hudak, Nicholas S.; Amatucci, Glenn G.

    2008-05-01

    As sensors for a wide array of applications continue to shrink and become integrated, increasing attention has been focused on creating autonomous devices with long-lasting power supplies. To achieve this, energy will have to be harvested from the sensors' environment. An energy harvesting device can power the sensor either directly or in conjunction with a battery. Presented herein is a review of three types of energy harvesting with focus on devices at or below the cm3 scale. The harvesting technologies discussed are based on the conversion of temperature gradients, mechanical vibrations, and radiofrequency waves. Operation principles, current state of the art, and materials issues are presented. In addition, requirements and recent developments in power conditioning for such devices are discussed. Future challenges specific to miniaturization are outlined from both the materials and device perspectives.

  20. 77 FR 22472 - Energy Conservation Program: Energy Conservation Standards for Certain External Power Supplies...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-16

    ...EERE-2008-BT-STD-0005] RIN 1904-AB57 Energy Conservation Program: Energy Conservation Standards for Certain External Power Supplies...correction to its regulations pertaining to the energy conservation standards for certain external power...

  1. A 4 MA, 500 ns pulsed power generator CQ-4 for characterization of material behaviors under ramp wave loading

    NASA Astrophysics Data System (ADS)

    Wang, Guiji; Luo, Binqiang; Zhang, Xuping; Zhao, Jianheng; Sun, Chengwei; Tan, Fuli; Chong, Tao; Mo, Jianjun; Wu, Gang; Tao, Yanhui

    2013-01-01

    A pulsed power generator CQ-4 was developed to characterize dynamic behaviors of materials under ramp wave loading, and to launch high velocity flyer plates for shock compression and hypervelocity impact experiments of materials and structures at Institute of Fluid Physics, China Academy of Engineering Physics. CQ-4 is composed of twenty capacitor and primary discharge switch modules with total capacitance of 32?F and rated charging voltage of 100 kV, and the storage energy is transmitted by two top and bottom parallel aluminum plates insulated by twelve layers of polyester film with total thickness of 1.2 mm. Between capacitor bank and chamber, there are 72 peaking capacitors with total capacitance of 7.2 ?F and rated voltage of 120 kV in parallel, which are connected with the capacitor bank in parallel. Before the load, there is a group of seven secondary self-breaking down switches connected with the total circuit in series. The peaking capacitors and secondary switches are used to shape the discharging current waveforms. For short-circuit, the peak current of discharging can be up to 3 ˜ 4 MA and rise time varies from 470 ns to 600 ns when the charging voltages of the generator are from 75 kV to 85 kV. With CQ-4 generator, some quasi-isentropic compression experiments under ramp wave loadings are done to demonstrate the ability of CQ-4 generator. And some experiments of launching high velocity flyer plates are also done on CQ-4. The experimental results show that ramp wave loading pressure of several tens of GPa on copper and aluminum samples can be realized and the velocity of aluminum flyer plate with size of 10 mm × 6 mm × 0.35 mm can be accelerated to about 11 km/s and the velocity of aluminum flyer plate with size of 10 mm × 6 mm × 0.6 mm can be up to about 9 km/s, which show that CQ-4 is a good and versatile tool to realize ramp wave loading and shock compression for shock physics.

  2. Small amplitude transverse waves on taut strings: exploring the significant effects of longitudinal motion on wave energy location and propagation

    NASA Astrophysics Data System (ADS)

    Rowland, David R.

    2013-03-01

    Introductory discussions of energy transport due to transverse waves on taut strings universally assume that the effects of longitudinal motion can be neglected, but this assumption is not even approximately valid unless the string is idealized to have a zero relaxed length, a requirement approximately met by the slinky spring. While making this additional idealization is probably the best approach to take when discussing waves on strings at the introductory level, for intermediate to advanced undergraduate classes in continuum mechanics and general wave phenomena where somewhat more realistic models of strings can be investigated, this paper makes the following contributions. First, various approaches to deriving the general energy continuity equation are critiqued and it is argued that the standard continuum mechanics approach to deriving such equations is the best because it leads to a conceptually clear, relatively simple derivation which provides a unique answer of greatest generality. In addition, a straightforward algorithm for calculating the transverse and longitudinal waves generated when a string is driven at one end is presented and used to investigate a cos2 transverse pulse. This example illustrates much important physics regarding energy transport in strings and allows the ‘attack waves’ observed when strings in musical instruments are struck or plucked to be approximately modelled and analysed algebraically. Regarding the ongoing debate as to whether the potential energy density in a string can be uniquely defined, it is shown by coupling an external energy source to a string that a suggested alternative formula for potential energy density requires an unphysical potential energy to be ascribed to the source for overall energy to be conserved and so cannot be considered to be physically valid.

  3. Creation of visible artificial optical emissions in the aurora by high-power radio waves.

    PubMed

    Pedersen, Todd R; Gerken, Elizabeth A

    2005-02-01

    Generation of artificial light in the sky by means of high-power radio waves interacting with the ionospheric plasma has been envisaged since the early days of radio exploration of the upper atmosphere, with proposed applications ranging from regional night-time street lighting to atmospheric measurements. Weak optical emissions have been produced for decades in such ionospheric 'heating' experiments, where they serve as key indicators of electron acceleration, thermal heating, and other effects of incompletely understood wave-particle interactions in the plasma under conditions difficult to replicate in the laboratory. The extremely low intensities produced previously have, however, required sensitive instrumentation for detection, preventing applications beyond scientific research. Here we report observations of radio-induced optical emissions bright enough to be seen by the naked eye, and produced not in the quiet mid-latitude ionosphere, but in the midst of a pulsating natural aurora. This may open the door to visual applications of ionospheric heating technology or provide a way to probe the dynamics of the natural aurora and magnetosphere. PMID:15690034

  4. Creation of visible artificial optical emissions in the aurora by high-power radio waves

    NASA Astrophysics Data System (ADS)

    Pedersen, Todd. R.; Gerken, Elizabeth A.

    2005-02-01

    Generation of artificial light in the sky by means of high-power radio waves interacting with the ionospheric plasma has been envisaged since the early days of radio exploration of the upper atmosphere, with proposed applications ranging from regional night-time street lighting to atmospheric measurements. Weak optical emissions have been produced for decades in such ionospheric `heating' experiments, where they serve as key indicators of electron acceleration, thermal heating, and other effects of incompletely understood wave-particle interactions in the plasma under conditions difficult to replicate in the laboratory. The extremely low intensities produced previously have, however, required sensitive instrumentation for detection, preventing applications beyond scientific research. Here we report observations of radio-induced optical emissions bright enough to be seen by the naked eye, and produced not in the quiet mid-latitude ionosphere, but in the midst of a pulsating natural aurora. This may open the door to visual applications of ionospheric heating technology or provide a way to probe the dynamics of the natural aurora and magnetosphere.

  5. Optimization of the coupling of mm wave power to arrays of high-Tc Josephson junctions

    NASA Astrophysics Data System (ADS)

    Klushin, A. M.; He, M.; Levitchev, M. Yu; Kurin, V. V.; Klein, N.

    2008-02-01

    We explored high-temperature superconductor Josephson junction arrays embedded in a hemispherical Fabry-Perot resonator. We compared the characteristics of three designs of arrays to achieve steps at higher voltage with a better coupling to the millimeter wave irradiation power. With an optimal design, we achieved a maximum Josephson voltage of about 0.1V for an array of 620 bicrystal junctions at a temperature of 79.2K and a frequency of 77.465 GHz. Also steps from 0.01 V up to 0.1 V were observed. Our results showed that such circuits are challenging for applications in quantum voltage metrology. It is important to note that our quasioptical coupling method can be extended up to terahertz frequencies.

  6. High-power continuous-wave interband cascade lasers with 10 active stages.

    PubMed

    Kim, Mijin; Bewley, William W; Canedy, Chadwick L; Kim, Chul Soo; Merritt, Charles D; Abell, Joshua; Vurgaftman, Igor; Meyer, Jerry R

    2015-04-20

    We report the pulsed and continuous wave (cw) performance of 10-stage interband cascade lasers (ICLs) emitting at both ? ?3.2 ?m and ? ?3.45 ?m. The slope efficiency is higher while the external differential quantum efficiency per stage remains about the same when comparison is made to earlier results for 7-stage ICLs with similar carrier-rebalanced designs. At T = 25°C, an 18-?m-wide ridge with 4.5 mm cavity length and high-reflection/anti-reflection coatings emits up to 464 mW of cw output power with beam quality factor M(2) = 1.9, for higher brightness than has ever been reported previously for an ICL. When the cavity length is reduced to 1 mm, both the 10-stage and 7-stage devices reach 18% cw wallplug efficiency at T = 25°C. PMID:25969003

  7. Total power millimeter-wave spectrometer for measurements of dust opacity at cryogenic temperatures.

    PubMed

    Potapov, Alexey; Lewen, Frank; Mutschke, Harald; Mohr, Pierre; Schlemmer, Stephan

    2014-07-01

    A highly sensitive total power millimeter-wave spectrometer has been built to investigate the opacity of important interstellar-dust analogues in the 10-300 K temperature range. The key elements of the spectrometer are a frequency agile synthesizer followed by a microwave amplifier and a subsequent frequency multiplier. In a first step, the frequency range of 72-120 GHz is covered by the spectrometer, and a room temperature Schottky detector is employed as a detector. A newly developed two channel (sample/reference) copper sample holder is cryogenically cooled for the 10-300 K range. Here we present the technical details of the spectrometer including examples of the obtained results. The analysis of these results will be published elsewhere. PMID:25085122

  8. High power wideband gyrotron backward wave oscillator operating towards the terahertz region.

    PubMed

    He, W; Donaldson, C R; Zhang, L; Ronald, K; McElhinney, P; Cross, A W

    2013-04-19

    Experimental results are presented of the first successful gyrotron backward wave oscillator (gyro-BWO) with continuous frequency tuning near the low-terahertz region. A helically corrugated interaction region was used to allow efficient interaction over a wide frequency band at the second harmonic of the electron cyclotron frequency without parasitic output. The gyro-BWO generated a maximum output power of 12 kW when driven by a 40 kV, 1.5 A, annular-shaped large-orbit electron beam and achieved a frequency tuning band of 88-102.5 GHz by adjusting the cavity magnetic field. The performance of the gyro-BWO is consistent with 3D particle-in-cell numerical simulations. PMID:23679610

  9. Bayesian semiparametric power spectral density estimation with applications in gravitational wave data analysis

    NASA Astrophysics Data System (ADS)

    Edwards, Matthew C.; Meyer, Renate; Christensen, Nelson

    2015-09-01

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

  10. Interferometric adaptive optics for high power laser pointing, wave-front control and phasing

    SciTech Connect

    Baker, K L; Stappaerts, E A; Homoelle, D C; Henesian, M A; Bliss, E S; Siders, C W; Barty, C J

    2009-01-21

    Implementing the capability to perform fast ignition experiments, as well as, radiography experiments on the National Ignition Facility (NIF) places stringent requirements on the control of each of the beam's pointing and overall wavefront quality. One quad of the NIF beams, 4 beam pairs, will be utilized for these experiments and hydrodynamic and particle-in-cell simulations indicate that for the fast ignition experiments, these beams will be required to deliver 50% (4.0 kJ) of their total energy (7.96 kJ) within a 40 {micro}m diameter spot at the end of a fast ignition cone target. This requirement implies a stringent pointing and overall phase conjugation error budget on the adaptive optics system used to correct these beam lines. The overall encircled energy requirement is more readily met by phasing of the beams in pairs but still requires high Strehl ratios, Sr, and rms tip/tilt errors of approximately one {micro}rad. To accomplish this task we have designed an interferometric adaptive optics system capable of beam pointing, high Strehl ratio and beam phasing with a single pixilated MEMS deformable mirror and interferometric wave-front sensor. We present the design of a testbed used to evaluate the performance of this wave-front sensor below along with simulations of its expected performance level.

  11. Energy in elastic fiber embedded in elastic matrix containing incident SH wave

    NASA Technical Reports Server (NTRS)

    Williams, James H., Jr.; Nagem, Raymond J.

    1989-01-01

    A single elastic fiber embedded in an infinite elastic matrix is considered. An incident plane SH wave is assumed in the infinite matrix, and an expression is derived for the total energy in the fiber due to the incident SH wave. A nondimensional form of the fiber energy is plotted as a function of the nondimensional wavenumber of the SH wave. It is shown that the fiber energy attains maximum values at specific values of the wavenumber of the incident wave. The results obtained here are interpreted in the context of phenomena observed in acousto-ultrasonic experiments on fiber reinforced composite materials.

  12. Relation between fine structure of energy spectra for pulsating aurora electrons and frequency spectra of whistler mode chorus waves

    NASA Astrophysics Data System (ADS)

    Miyoshi, Y.; Saito, S.; Seki, K.; Nishiyama, T.; Kataoka, R.; Asamura, K.; Katoh, Y.; Ebihara, Y.; Sakanoi, T.; Hirahara, M.; Oyama, S.; Kurita, S.; Santolik, O.

    2015-09-01

    We investigate the origin of the fine structure of the energy spectrum of precipitating electrons for the pulsating aurora (PsA) observed by the low-altitude Reimei satellite. The Reimei satellite achieved simultaneous observations of the optical images and precipitating electrons of the PsA from satellite altitude (~620 km) with resolution of 40 ms. The main modulation of precipitation, with a few seconds, and the internal modulations, with a few hertz, that are embedded inside the main modulations are identified above ~3 keV. Moreover, stable precipitations at ~1 keV are found for the PsA. A "precipitation gap" is discovered between two energy bands. We identify the origin of the fine structure of the energy spectrum for the precipitating electrons using the computer simulation on the wave-particle interaction between electrons and chorus waves. The lower band chorus (LBC) bursts cause the main modulation of energetic electrons, and the generation and collapse of the LBC bursts determines on-off switching of the PsA. A train of rising tone elements embedded in the LBC bursts drives the internal modulations. A close set of upper band chorus (UBC) waves causes the stable precipitations at ~1 keV. We show that a wave power gap around the half gyrofrequency at the equatorial plane in the magnetosphere between LBC and UBC reduces the loss rate of electrons at the intermediate energy range, forming a gap of precipitating electrons in the ionosphere.

  13. Hydrogen storage of energy for small power supply systems

    E-print Network

    Monaghan, Rory F. D. (Rory Francis Desmond)

    2005-01-01

    Power supply systems for cell phone base stations using hydrogen energy storage, fuel cells or hydrogen-burning generators, and a backup generator could offer an improvement over current power supply systems. Two categories ...

  14. A linear relationship between wave power and erosion determines salt-marsh resilience to violent storms and hurricanes.

    PubMed

    Leonardi, Nicoletta; Ganju, Neil K; Fagherazzi, Sergio

    2016-01-01

    Salt marsh losses have been documented worldwide because of land use change, wave erosion, and sea-level rise. It is still unclear how resistant salt marshes are to extreme storms and whether they can survive multiple events without collapsing. Based on a large dataset of salt marsh lateral erosion rates collected around the world, here, we determine the general response of salt marsh boundaries to wave action under normal and extreme weather conditions. As wave energy increases, salt marsh response to wind waves remains linear, and there is not a critical threshold in wave energy above which salt marsh erosion drastically accelerates. We apply our general formulation for salt marsh erosion to historical wave climates at eight salt marsh locations affected by hurricanes in the United States. Based on the analysis of two decades of data, we find that violent storms and hurricanes contribute less than 1% to long-term salt marsh erosion rates. In contrast, moderate storms with a return period of 2.5 mo are those causing the most salt marsh deterioration. Therefore, salt marshes seem more susceptible to variations in mean wave energy rather than changes in the extremes. The intrinsic resistance of salt marshes to violent storms and their predictable erosion rates during moderate events should be taken into account by coastal managers in restoration projects and risk management plans. PMID:26699461

  15. iPower: An Energy Conservation System for

    E-print Network

    Tseng, Yu-Chee

    iPower: An Energy Conservation System for Intelligent Buildings by Wireless Sensor Networks Lun. Exploiting the context-aware capability of WSN to achieve energy conservation in intelligent buildings is an attractive direction. We thus propose an iPower (intelligent and personalized energy-conservation system

  16. Optimal Power Cost Management Using Stored Energy in Data Centers

    E-print Network

    Giles, C. Lee

    the aver- age price of 1 MW-Hour of electricity. Consequently, mini- mization of energy consumption needOptimal Power Cost Management Using Stored Energy in Data Centers Rahul Urgaonkar, Bhuvan Urgaonkar that arise by the use of uninterrupted power supply (UPS) units as energy storage devices. This rep- resents

  17. Efficiently Operating Wireless Nodes Powered by Renewable Energy Sources

    E-print Network

    Gautam, Natarajan

    1 Efficiently Operating Wireless Nodes Powered by Renewable Energy Sources Natarajan Gautam Senior. The node uses energy harvesting in the sense that it is powered by batteries that are charged by renewable that is responsible for transmitting messages in a timely manner while being prudent about energy consumption

  18. 75 FR 35786 - Resale Power Group of Iowa, WPPI Energy v. ITC Midwest LLC, Interstate Power and Light Company...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-06-23

    ...DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket...Resale Power Group of Iowa, WPPI Energy v. ITC Midwest LLC, Interstate...Resale Power Group of Iowa and WPPI Energy filed a supplement to its complaint originally...

  19. 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

    ... Energy Regulatory Commission Oregon Wave Energy Partners I, LLC; Notice of Preliminary Permit Application..., 2010. On March 2, 2010, Oregon Wave Energy Partners I, LLC filed an application for a subsequent.... Applicant Contact: Mr. Charles F. Dunleavy, Oregon Wave Energy Partners I, LLC, 1590 Reed Road,...

  20. The synoptic setting and possible energy sources for mesoscale wave disturbances

    NASA Technical Reports Server (NTRS)

    Uccellini, Louis W.; Koch, Steven E.

    1987-01-01

    Published data on 13 cases of mesoscale wave disturbances and their environment were examined to isolate common features for these cases and to determine possible energy sources for the waves. These events are characterized by either a singular wave of depression or wave packets with periods of 1-4 h, horizontal wavelengths of 50-500 km, and surface-pressure perturbation amplitudes of 0.2-7.0 mb. These wave events are shown to be associated with a distinct synoptic pattern (including the existence of a strong inversion in the lower troposphere and the propagation of a jet streak toward a ridge axis in the upper troposphere) while displaying little correlation with the presence of convective storm cells. The observed development of the waves is consistent with the hypothesis that the energy source needed to initiate and sustain the wave disturbances may be related to a geostrophic adjustment process associated with upper-tropospheric jet streaks.

  1. Comparison of magnetosonic wave and water group ion energy densities at Comet Giacobini-Zinner

    NASA Technical Reports Server (NTRS)

    Staines, K.; Balogh, A.; Cowley, S. W. H.; Forster, P. M. De F.; Hynds, R. J.; Yates, T. S.; Sanderson, T. R.; Wenzel, K.-P.; Tsurutani, B. T.

    1991-01-01

    Measurements of the Comet Giacobini-Zinner (GZ) are presented to determine to what extent wave-particle scattering redistributed the initial pick-up energy of the ion population. Also examined is the difference between the ion thermal energy and the energy in the magnetic fields of the waves. In spite of uncertainty of about a factor of 2 noted in the pick-up and mass-loaded regions, it is shown that less than approximately 50 percent of the pick-up energy is converted into wave magnetic energy in the inbound pick-up region.

  2. Version 2.0 Ground state wave function and energy of the lithium atom

    E-print Network

    Pachucki, Krzysztof

    Version 2.0 Ground state wave function and energy of the lithium atom Mariusz Puchalski Abstract Highly accurate nonrelativistic ground­state wave function and energy of the lithium atom# 6 corrections has been obtained for few low lying states of helium only [2, 3], not for lithium nor

  3. Wave Energy Converter Design Tool for Point Absorbers with Arbitrary Device Geometry Kelley Ruehl

    E-print Network

    Siefert, Chris

    Wave Energy Converter Design Tool for Point Absorbers with Arbitrary Device Geometry Kelley Ruehl device geometry. The design tool provides a numerical modeling structure and methodology capable wave energy research is largely influenced by developer needs and lessons learned from related

  4. Global dynamics of the nonradial energy-critical wave equation above the ground state energy

    E-print Network

    Krieger, Joachim; Schlag, Wilhelm

    2011-01-01

    In this paper we establish the existence of certain classes of solutions to the energy critical nonlinear wave equation in dimensions 3 and 5 assuming that the energy exceeds the ground state energy only by a small amount. No radial assumption is made. We find that there exist four sets in the natural energy space with nonempty interiors which correspond to all possible combinations of finite-time blowup on the one hand, and global existence and scattering to a free wave, on the other hand, as time approaches infinity. In our previous paper arxiv:1010.3799 we treated the radial case, and this paper provides the natural nonradial extension of these results. However, the present paper is self-contained and in fact develops a somewhat different formalism in order to handle the more complex nonradial situation.

  5. Effect of Stress on Energy Flux Deviation of Ultrasonic Waves in Ultrasonic Waves in GR/EP Composites

    NASA Technical Reports Server (NTRS)

    Prosser, William H.; Kriz, R. D.; Fitting, Dale W.

    1990-01-01

    Ultrasonic waves suffer energy flux deviation in graphite/epoxy because of the large anisotropy. The angle of deviation is a function of the elastic coefficients. For nonlinear solids, these coefficients and thus the angle of deviation is a function of stress. Acoustoelastic theory was used to model the effect of stress on flux deviation for unidirectional T300/5208 using previously measured elastic coefficients. Computations were made for uniaxial stress along the x3 axis fiber axis) and the x1 axis for waves propagating in the x1x3 plane. These results predict a shift as large as three degrees for the quasi-transverse wave. The shift in energy flux offers new nondestructive technique of evaluating stress in composites.

  6. Adiabatic corrections to density functional theory energies and wave functions.

    PubMed

    Mohallem, José R; Coura, Thiago de O; Diniz, Leonardo G; de Castro, Gustavo; Assafrão, Denise; Heine, Thomas

    2008-09-25

    The adiabatic finite-nuclear-mass-correction (FNMC) to the electronic energies and wave functions of atoms and molecules is formulated for density-functional theory and implemented in the deMon code. The approach is tested for a series of local and gradient corrected density functionals, using MP2 results and diagonal-Born-Oppenheimer corrections from the literature for comparison. In the evaluation of absolute energy corrections of nonorganic molecules the LDA PZ81 functional works surprisingly better than the others. For organic molecules the GGA BLYP functional has the best performance. FNMC with GGA functionals, mainly BLYP, show a good performance in the evaluation of relative corrections, except for nonorganic molecules containing H atoms. The PW86 functional stands out with the best evaluation of the barrier of linearity of H2O and the isotopic dipole moment of HDO. In general, DFT functionals display an accuracy superior than the common belief and because the corrections are based on a change of the electronic kinetic energy they are here ranked in a new appropriate way. The approach is applied to obtain the adiabatic correction for full atomization of alcanes C(n)H(2n+2), n = 4-10. The barrier of 1 mHartree is approached for adiabatic corrections, justifying its insertion into DFT. PMID:18537228

  7. Estimating wave energy dissipation in the surf zone using thermal infrared imagery

    NASA Astrophysics Data System (ADS)

    Carini, Roxanne J.; Chickadel, C. Chris; Jessup, Andrew T.; Thomson, Jim

    2015-06-01

    Thermal infrared (IR) imagery is used to quantify the high spatial and temporal variability of dissipation due to wave breaking in the surf zone. The foam produced in an actively breaking crest, or wave roller, has a distinct signature in IR imagery. A retrieval algorithm is developed to detect breaking waves and extract wave roller length using measurements taken during the Surf Zone Optics 2010 experiment at Duck, NC. The remotely derived roller length and an in situ estimate of wave slope are used to estimate dissipation due to wave breaking by means of the wave-resolving model by Duncan (1981). The wave energy dissipation rate estimates show a pattern of increased breaking during low tide over a sand bar, consistent with in situ turbulent kinetic energy dissipation rate estimates from fixed and drifting instruments over the bar. When integrated over the surf zone width, these dissipation rate estimates account for 40-69% of the incoming wave energy flux. The Duncan (1981) estimates agree with those from a dissipation parameterization by Janssen and Battjes (2007), a wave energy dissipation model commonly applied within nearshore circulation models.

  8. Ultra High Energy Electrons Powered by Pulsar Rotation

    NASA Astrophysics Data System (ADS)

    Mahajan, Swadesh; Machabeli, George; Osmanov, Zaza; Chkheidze, Nino

    2013-02-01

    A new mechanism of particle acceleration, driven by the rotational slow down of the Crab pulsar, is explored. The rotation, through the time dependent centrifugal force, can efficiently excite unstable Langmuir waves in the electron-positron (hereafter e+/-) plasma of the star magnetosphere. These waves, then, Landau damp on electrons accelerating them in the process. The net transfer of energy is optimal when the wave growth and the Landau damping times are comparable and are both very short compared to the star rotation time. We show, by detailed calculations, that these are precisely the conditions for the parameters of the Crab pulsar. This highly efficient route for energy transfer allows the electrons in the primary beam to be catapulted to multiple TeV (~ 100 TeV) and even PeV energy domain. It is expected that the proposed mechanism may, unravel the puzzle of the origin of ultra high energy cosmic ray electrons.

  9. Ultra high energy electrons powered by pulsar rotation.

    PubMed

    Mahajan, Swadesh; Machabeli, George; Osmanov, Zaza; Chkheidze, Nino

    2013-01-01

    A new mechanism of particle acceleration, driven by the rotational slow down of the Crab pulsar, is explored. The rotation, through the time dependent centrifugal force, can efficiently excite unstable Langmuir waves in the electron-positron (hereafter e(±)) plasma of the star magnetosphere. These waves, then, Landau damp on electrons accelerating them in the process. The net transfer of energy is optimal when the wave growth and the Landau damping times are comparable and are both very short compared to the star rotation time. We show, by detailed calculations, that these are precisely the conditions for the parameters of the Crab pulsar. This highly efficient route for energy transfer allows the electrons in the primary beam to be catapulted to multiple TeV (~ 100?TeV) and even PeV energy domain. It is expected that the proposed mechanism may, unravel the puzzle of the origin of ultra high energy cosmic ray electrons. PMID:23405276

  10. Ultra High Energy Electrons Powered by Pulsar Rotation

    PubMed Central

    Mahajan, Swadesh; Machabeli, George; Osmanov, Zaza; Chkheidze, Nino

    2013-01-01

    A new mechanism of particle acceleration, driven by the rotational slow down of the Crab pulsar, is explored. The rotation, through the time dependent centrifugal force, can efficiently excite unstable Langmuir waves in the electron-positron (hereafter e±) plasma of the star magnetosphere. These waves, then, Landau damp on electrons accelerating them in the process. The net transfer of energy is optimal when the wave growth and the Landau damping times are comparable and are both very short compared to the star rotation time. We show, by detailed calculations, that these are precisely the conditions for the parameters of the Crab pulsar. This highly efficient route for energy transfer allows the electrons in the primary beam to be catapulted to multiple TeV (~ 100?TeV) and even PeV energy domain. It is expected that the proposed mechanism may, unravel the puzzle of the origin of ultra high energy cosmic ray electrons. PMID:23405276

  11. Verification of Hasselmann's energy transfer among surface gravity waves by direct numerical simulations of primitive equations

    NASA Astrophysics Data System (ADS)

    Tanaka, Mitsuhiro

    2001-10-01

    The temporal evolution of nonlinear wave fields of surface gravity waves is studied by large-scale direct numerical simulations of primitive equations in order to verify Hasselmann's theory for nonlinear energy transfer among component gravity waves. In the simulations, all the nonlinear interactions, including both resonant and non-resonant ones, are taken into account up to the four-wave processes. The initial wave field is constructed by combining more than two million component free waves in such a way that it has the JONSWAP or the Pierson Moskowitz spectrum. The nonlinear energy transfer is evaluated from the rate of change of the spectrum, and is compared with Hasselmann's theory. It is shown that, in spite of apparently insufficient duration of the simulations such as just a few tens of characteristic periods, the energy transfer obtained by the present method shows satisfactory agreement with Hasselmann's theory, at least in their qualitative features.

  12. Wave-speed dispersion associated with an attenuation obeying a frequency power law.

    PubMed

    Buckingham, Michael J

    2015-11-01

    An attenuation scaling as a power of frequency, |?|(?), over an infinite bandwidth is neither analytic nor square-integrable, thus calling into question the application of the Kramers-Krönig dispersion relations for determining the frequency dependence of the associated phase speed. In this paper, three different approaches are developed, all of which return the dispersion formula for the wavenumber, K(?). The first analysis relies on the properties of generalized functions and the causality requirement that the impulse response, k(t), the inverse Fourier transform of -iK(?), must vanish for t?wave equation is introduced that yields the phase-speed dispersion associated with a frequency-power-law attenuation. Finally, it is shown that, with minor modification, the Kramers-Krönig dispersion relations with no subtractions (the Plemelj formulas) do in fact hold for an attenuation scaling as |?|(?), yielding the same dispersion formula as the other two derivations. From this dispersion formula, admissible values of the exponent ? are established. Physically, the inadmissible values of ?, which include all the integers, correspond to attenuation-dispersion pairs whose Fourier components cannot combine in such a way as to make the impulse response, k(t), vanish for t?

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

    E-print Network

    J. S. Sanders; A. C. Fabian

    2007-08-15

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

  14. The physical basis for estimating wave-energy spectra with the radar ocean-wave spectrometer

    NASA Technical Reports Server (NTRS)

    Jackson, Frederick C.

    1987-01-01

    The derivation of the reflectivity modulation spectrum of the sea surface for near-nadir-viewing microwave radars using geometrical optics is described. The equations required for the derivation are presented. The derived reflectivity modulation spectrum provides data on the physical basis of the radar ocean-wave spectrometer measurements of ocean-wave directional spectra.

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

    E-print Network

    Haller, Merrick

    (as opposed to on a platform), offshore, in waters of moderate depth. In the future they may.g. the 100-year design wave). This is relevant for many platforms, but it is not necessarily applicable with no trouble while the same wave inundates a platform causing extensive damage. Conversely, a shorter plunging

  16. Energy: Add Power to Your Collection.

    ERIC Educational Resources Information Center

    Rholes, Julia M.

    1981-01-01

    An annotated bibliography of 34 children's books on different types of energy at various reading levels includes general titles, as well as books on coal, geothermal energy, nuclear energy, ocean engineering, petroleum, solar energy, and wind energy. (CHC)

  17. Generation of Acoustic Gravity Waves by Periodic Radio Transmissions from a High-Power Ionospheric Heater

    NASA Astrophysics Data System (ADS)

    Frolov, Vladimir; Chernogor, Leonid; Rozumenko, Victor

    The Radiophysical Research Institute (Nizhny Novgorod, Russia) and Kharkiv V. N. Karazin National University (Kharkiv, Ukraine) have studied opportunities for the effective generation of acoustic gravity waves (AGWs) in 3 - 180-min period range. The excitation of such waves was conducted for the last several years using the SURA heating facility (Nizhny Novgorod). The detection of the HF-induced AGWs was carried out in the Radiophysical Observatory located near Kharkiv City at a distance of about 960 km from the SURA. A coherent radar for vertical sounding, an ionosonde, and magnetometer chains were used in our measurements. The main results are the following (see [1-5]): 1. Infrasound oscillation trains with a period of 6 min are detected during periodic SURA heater turn-on and -off. Similar oscillation trains are detected after long time pumping, during periodic transmissions with a period of 20 s, as well as after pumping turn-off. The train recordings begin 28 - 54 min after the heater turn-on or -off, and the train propagation speeds are about 300 - 570 m/s, the value of which is close to the sound speed at upper atmospheric altitudes. The amplitude of the Doppler shift frequency is of 10 - 40 mHz, which fits to the 0.1 - 0.3% electron density disturbances at ionospheric altitudes. The amplitude of the infrasound oscillations depends on the SURA mode of operation and the state of the upper atmosphere and ionosphere. 2. High-power radio transmissions stimulate the generation (or enhancement) of waves at ionospheric altitudes in the range of internal gravity wave periods. The HF-induced waves propagate with speeds of 360 - 460 m/s and produce changes in electron density with amplitudes of 2 - 3%. The generation of such periodic perturbations is more preferable with periods of 10 - 60 minutes. Their features depend significantly on the heater mode of operation. It should be stressed that perturbation intensity increases when a pumping wave frequency approaches the F _{_2} layer critical frequency. High-power periodic radio transmissions are capable of enhancing/damping natural wave perturbations generated by the solar terminator. 3. The study has demonstrated that the generation and propagation of AGWs with periods close to the natural oscillation periods of the atmosphere is possible. The duration of AGW oscillation trains does not dependent on the duration of turn-on/-off trains, but it is determined by changes in the current state of the atmosphere-ionosphere-magnetosphere system in general. The period of the AGW oscillation trains is determined by the period or semi-period of the pumping. It means that the mechanism of AGW generation in this case is distinct from the agreed-upon mechanism developed earlier. The AGWs, whose periods are 5 - 10% greater than the Brunt-Vaisala period, exhibit group velocities less than the speed of sound that is of about 80 - 160 m/s. They induce electron density perturbations of about 1.1 - 1.5%. The AGW generation has the following features. When the effective radiated power (ERP) is 50 MW or less, AGWs are not detected; they are reliably observed when the ERP is equal or larger than about 100 MW. Geomagnetic storms play a dual role in the AGW generation because they: (i) increase amplitudes of AGWs with 4 - 6-min and 8 - 12-min periods and (ii) yet enhance background oscillations. The latter hampers the identification of the HF-induced oscillations. Moderate magnetic storms do not markedly exert an influence on the amplitudes of oscillations with 13 - 17-min periods. 4. The quasi-periodic variations in the horizontal components of the geomagnetic field with 8 - 12-min periods become observable near Kharkiv 35 - 45 min after the beginning of pumping. Their speeds are 355 - 460 m/s, and they form trains 40 - 90 min in duration when the [5-min on, 5-min off] or [10-min on, 10-min off] heater timing is used. The 12 - 18-min period variations become observable 35 - 45 min after the beginning of pumping. Their speeds are 355 - 460 m/s, and they form trains 55 - 90 min in duration when the

  18. Survey of energy harvesting and energy scavenging approaches for on-site powering of wireless sensor- and microinstrument-networks

    NASA Astrophysics Data System (ADS)

    Lee, D.; Dulai, G.; Karanassios, Vassili

    2013-05-01

    Energy (or power) harvesting can be defined as the gathering and either storing or immediately using energy "freely" available in a local environment. Examples include harvesting energy from obvious sources such as photon-fluxes (e.g., solar), or wind or water waves, or from unusual sources such as naturally occurring pH differences. Energy scavenging can be defined as gathering and storing or immediately re-using energy that has been discarded, for instance, waste heat from air conditioning units, from in-door lights or from everyday actions such as walking or from body-heat. Although the power levels that can be harvested or scavenged are typically low (e.g., from nWatt/cm2 to mWatt/cm2), the key motivation is to harvest or to scavenge energy for a wide variety of applications. Example applications include powering devices in remote weather stations, or wireless Bluetooth headsets, or wearable computing devices or for sensor networks for health and bio-medical applications. Beyond sensors and sensor networks, there is a need to power compete systems, such as portable and energy-autonomous chemical analysis microinstruments for use on-site. A portable microinstrument is one that offers the same functionality as a large one but one that has at least one critical component in the micrometer regime. This paper surveys continuous or discontinuous energy harvesting and energy scavenging approaches (with particular emphasis on sensor and microinstrument networks) and it discusses current trends. It also briefly explores potential future directions, for example, for nature-inspired (e.g., photosynthesis), for human-power driven (e.g., for biomedical applications, or for wearable sensor networks) or for nanotechnology-enabled energy harvesting and energy scavenging approaches.

  19. Acceleration of low-energy protons and alpha particles at interplanetary shock waves

    NASA Technical Reports Server (NTRS)

    Scholer, M.; Hovestadt, D.; Ipavich, F. M.; Gloeckler, G.

    1983-01-01

    The low-energy protons and alpha particles in the energy range 30 keV/charge to 150 keV/charge associated with three different interplanetary shock waves in the immediate preshock and postshock region are studied using data obtained by the ISEE 3. The spatial distributions in the preshock and postshock medium are presented, and the dependence of the phase space density at different energies on the distance from the shock and on the form of the distribution function of both species immediately at the shock is examined. It is found that in the preshock region the particles are flowing in the solar wind frame of reference away from the shock and in the postshock medium the distribution is more or less isotropic in this frame of reference. The distribution function in the postshock region can be represented by a power law in energy which has the same spectral exponent for both protons and alpha particles. It is concluded that the first-order Fermi acceleration process can consistently explain the data, although the spectra of diffuse bow shock associated particles are different from the spectra of the interplanetary shock-associated particles in the immediate vicinity of the shock. In addition, the mean free path of the low energy ions in the preshock medium is found to be considerably smaller than the mean free path determined by the turbulence of the background interplanetary medium.

  20. Direct conversion of infrared radiant energy for space power applications

    NASA Technical Reports Server (NTRS)

    Finke, R. C.

    1982-01-01

    A proposed technology to convert the earth radiant energy (infrared albedo) for spacecraft power is presented. The resultant system would eliminate energy storage requirements and simplify the spacecraft design. The design and performance of a infrared rectenna is discussed.

  1. A geospatial assessment of the relationship between reef flat community calcium carbonate production and wave energy

    NASA Astrophysics Data System (ADS)

    Hamylton, S. M.; Pescud, A.; Leon, J. X.; Callaghan, D. P.

    2013-12-01

    The ability of benthic communities inhabiting coral reefs to produce calcium carbonate underpins the development of reef platforms and associated sedimentary landforms, as well as the fixation of inorganic carbon and buffering of diurnal pH fluctuations in ocean surface waters. Quantification of the relationship between reef flat community calcium carbonate production and wave energy provides an empirical basis for understanding and managing this functionally important process. This study employs geospatial techniques across the reef platform at Lizard Island, Great Barrier Reef, to (1) map the distribution and estimate the total magnitude of reef community carbonate production and (2) empirically ascertain the influence of wave energy on community carbonate production. A World-View-2 satellite image and a field data set of 364 ground referencing points are employed, along with data on physical reef characteristics (e.g. bathymetry, rugosity) to map and validate the spatial distribution of the four major community carbonate producers (live coral, carbonate sand, green calcareous macroalgae and encrusting calcified algae) across the reef platform. Carbonate production is estimated for the complete reef platform from the composition of these community components. A synoptic model of wave energy is developed using the Simulating WAves Nearshore (SWAN) two-dimensional model for the entire reef platform. The relationship between locally derived measures of carbonate production and wave energy is evaluated at both the global scale and local scale along spatial gradients of wave energy traversing the reef platform. A wave energy threshold is identified, below which carbonate production levels appear to increase with wave energy and above which mechanical forcing reduces community production. This implies an optimal set of hydrodynamic conditions characterized by wave energy levels of approximately 300 J m-2, providing an empirical basis for management of potential changes in community carbonate production associated with climate change-driven increases in wave energy.

  2. Investigation of the effect of the structure of large-area carbon nanotube/fuel composites on energy generation from thermopower waves

    PubMed Central

    2014-01-01

    Thermopower waves are a recently developed energy conversion concept utilizing dynamic temperature and chemical potential gradients to harvest electrical energy while the combustion wave propagates along the hybrid layers of nanomaterials and chemical fuels. The intrinsic properties of the core nanomaterials and chemical fuels in the hybrid composites can broadly affect the energy generation, as well as the combustion process, of thermopower waves. So far, most research has focused on the application of new core nanomaterials to enhance energy generation. In this study, we demonstrate that the alignment of core nanomaterials can significantly influence a number of aspects of the thermopower waves, while the nanomaterials involved are identical carbon nanotubes (CNTs). Diversely structured, large-area CNT/fuel composites of one-dimensional aligned CNT arrays (1D CNT arrays), randomly oriented CNT films (2D CNT films), and randomly aggregated bulk CNT clusters (3D CNT clusters) were fabricated to evaluate the energy generation, as well as the propagation of the thermal wave, from thermopower waves. The more the core nanostructures were aligned, the less inversion of temperature gradients and the less cross-propagation of multiple thermopower waves occurred. These characteristics of the aligned structures prevented the cancellation of charge carrier movements among the core nanomaterials and produced the relative enhancement of the energy generation and the specific power with a single-polarity voltage signal. Understanding this effect of structure on energy generation from thermopower waves can help in the design of optimized hybrid composites of nanomaterials and fuels, especially designs based on the internal alignment of the materials. More generally, we believe that this work provides clues to the process of chemical to thermal to electrical energy conversion inside/outside hybrid nanostructured materials. PMID:25285059

  3. Optimized power simulation of AlGaN/GaN HEMT for continuous wave and pulse applications

    NASA Astrophysics Data System (ADS)

    Tiwat, Pongthavornkamol; Lei, Pang; Xinhua, Wang; Sen, Huang; Guoguo, Liu; Tingting, Yuan; Xinyu, Liu

    2015-07-01

    An optimized modeling method of 8 × 100 ?m AlGaN/GaN-based high electron mobility transistor (HEMT) for accurate continuous wave (CW) and pulsed power simulations is proposed. Since the self-heating effect can occur during the continuous operation, the power gain from the continuous operation significantly decreases when compared to a pulsed power operation. This paper extracts power performances of different device models from different quiescent biases of pulsed current-voltage (I-V) measurements and compared them in order to determine the most suitable device model for CW and pulse RF microwave power amplifier design. The simulated output power and gain results of the models at Vgs = -3.5 V, Vds = 30 V with a frequency of 9.6 GHz are presented. Project supported by the National Natural Science Foundation of China (No. 61204086).

  4. Technological cost-reduction pathways for attenuator wave energy converters in the marine hydrokinetic environment.

    SciTech Connect

    Bull, Diana L; Ochs, Margaret Ellen

    2013-09-01

    This report considers and prioritizes the primary potential technical costreduction pathways for offshore wave activated body attenuators designed for ocean resources. This report focuses on technical research and development costreduction pathways related to the device technology rather than environmental monitoring or permitting opportunities. Three sources of information were used to understand current cost drivers and develop a prioritized list of potential costreduction pathways: a literature review of technical work related to attenuators, a reference device compiled from literature sources, and a webinar with each of three industry device developers. Data from these information sources were aggregated and prioritized with respect to the potential impact on the lifetime levelized cost of energy, the potential for progress, the potential for success, and the confidence in success. Results indicate the five most promising costreduction pathways include advanced controls, an optimized structural design, improved power conversion, planned maintenance scheduling, and an optimized device profile.

  5. Third-order Coulomb corrections to the S-wave Green function, energy levels and wave functions at the origin

    E-print Network

    M. Beneke; Y. Kiyo; K. Schuller

    2007-05-30

    We obtain analytic expressions for the third-order corrections due to the strong interaction Coulomb potential to the S-wave Green function, energy levels and wave functions at the origin for arbitrary principal quantum number n. Together with the known non-Coulomb correction this results in the complete spectrum of S-states up to order alpha_s^5. The numerical impact of these corrections on the Upsilon spectrum and the top quark pair production cross section near threshold is estimated.

  6. Increase in the energy efficiency of a pulsed-periodic relativistic backward wave oscillator with a modulating resonant reflector

    NASA Astrophysics Data System (ADS)

    Tot'meninov, E. M.; Vykhodtsev, P. V.; Gunin, A. V.; Klimov, A. I.; Rostov, V. V.

    2014-03-01

    An efficient microwave oscillator (320 MW and 7.9 GHz) that generates microwave pulses with a duration of 90 ns is developed using optimization of an electron-wave system and decompression of the longitudinal magnetic field with a maximum induction of 0.62 T in the region of an explosive-emission cathode and a lower field (0.36 T) with respect to cyclotron resonance in the slow-wave structure. In a packet (up to 10 ns) repetitively-pulsed (100 Hz) regime, the maximum conversion efficiency of the electron-beam power to microwave radiation is 27%. The mean energy of the radiation pulse (23 J) is about 18% of the pulse energy of high-voltage oscillator.

  7. Energy-Saving RAM-Power Tap

    NASA Technical Reports Server (NTRS)

    Bruner, Alan Roy

    1987-01-01

    Reverse-flow HEXFET(R) minimizes voltage drop and power dissipation. HEXFET(R) scheme reduces voltage drop by approximately 80 percent. Design for power tap for random-access memory (RAM) has potential application in digital systems.

  8. Z-Pinch Inertial Fusion Energy Fusion Power Associates Annual

    E-print Network

    · Linear Transformer Driver technology · Pulsed power IFE #12;3 We were required to demonstrate 31 Z-Pinch Inertial Fusion Energy Fusion Power Associates Annual Meeting and Symposium December 4, 2008 Keith Matzen Pulsed Power Sciences Sandia National Laboratories (505-845-7756, mkmatze

  9. Energy/Water Sustainability and the Electric Power

    E-print Network

    Keller, Arturo A.

    Energy/Water Sustainability and the Electric Power Industry Robert Goldstein, Kent Zammit, Chuck Mc April 10, 2009 #12;2© 2009 Electric Power Research Institute, Inc. All rights reserved. Topics · Nature Electric Power Research Institute, Inc. All rights reserved. Big Picture · Water is a shared community

  10. A Revised Method of Presenting Wavenumber-Frequency Power Spectrum Diagrams That Reveals the Asymmetric Nature of Tropical Large-scale Waves

    NASA Technical Reports Server (NTRS)

    Chao, Winston C.; Yang, Bo; Fu, Xiouhua

    2007-01-01

    The popular method of presenting wavenumber-frequency power spectrum diagrams for studying tropical large-scale waves in the literature is shown to give an incomplete presentation of these waves. The so-called "convectively-coupled Kelvin (mixed Rossby-gravity) waves" are presented as existing only in the symmetric (antisymmetric) component of the diagrams. This is obviously not consistent with the published composite/regression studies of "convectively-coupled Kelvin waves," which illustrate the asymmetric nature of these waves. The cause of this inconsistency is revealed in this note and a revised method of presenting the power spectrum diagrams is proposed. When this revised method is used, "convectively-coupled Kelvin waves" do show anti-symmetric components, and "convectively-coupled mixed Rossby-gravity waves (also known as Yanai waves)" do show a hint of symmetric components. These results bolster a published proposal that these waves be called "chimeric Kelvin waves," "chimeric mixed Rossby-gravity waves," etc. This revised method of presenting power spectrum diagrams offers a more rigorous means of comparing the General Circulation Models (GCM) output with observations by calling attention to the capability of GCMs in correctly simulating the asymmetric characteristics of the equatorial waves.

  11. High Power and Efficiency Space Traveling-Wave Tube Amplifiers With Reduced Size and Mass for NASA Missions

    NASA Technical Reports Server (NTRS)

    Simons, Rainee N.; Wilson, Jeffrey D.; Force, Dale A.

    2008-01-01

    Recent advances in high power and efficiency space traveling-wave tube amplifiers (TWTAs) for NASA s space-to-Earth communications are presented in this paper. The RF power and efficiency of a new K-Band amplifier are 40 W and 50 percent and that of a new Ka-Band amplifier are 200 W and 60 percent. An important figure-of-merit, which is defined as the ratio of the RF power output to the mass (W/kg) of a TWT has improved by a factor of ten over the previous generation Ka-Band devices.

  12. Evaluation of quasi-square wave inverter as a power source for induction motors

    NASA Technical Reports Server (NTRS)

    Guynes, B. V.; Haggard, R. L.; Lanier, J. R., Jr.

    1977-01-01

    The relative merits of quasi-square wave inverter-motor technology versus a sine wave inverter-motor system were investigated. The empirical results of several tests on various sizes of wye-wound induction motors are presented with mathematical analysis to support the conclusions of the study. It was concluded that, within the limitations presented, the quasi-square wave inverter-motor system is superior to the more complex sine wave system for most induction motor applications in space.

  13. Gigawatt-class radiation generated by a Ka-band overmoded Cherenkov-type high power millimeter wave generator

    NASA Astrophysics Data System (ADS)

    Wu, Dapeng; Shu, Ting; Ju, Jinchuan; Peng, Shengren

    2015-08-01

    Particle simulation and experimental results are presented about a Ka-band overmoded Cherenkov-type high power millimeter wave generator in this paper. The relativistic electron beam with peak current of 8.4 kA was generated by a pulsed power accelerator working at the voltage of 625 kV, which was guided by an axial magnetic field of 1.05 T and transported through the beam-wave interaction structures. After careful calibration, the microwave power radiated in the far field was as high as about 500 MW, with a frequency of 32.1 GHz and a pulse width of 20 ns. The radiation mode was well controlled to be TM0n mode.

  14. Gigawatt-class radiation generated by a Ka-band overmoded Cherenkov-type high power millimeter wave generator.

    PubMed

    Wu, Dapeng; Shu, Ting; Ju, Jinchuan; Peng, Shengren

    2015-08-01

    Particle simulation and experimental results are presented about a Ka-band overmoded Cherenkov-type high power millimeter wave generator in this paper. The relativistic electron beam with peak current of 8.4 kA was generated by a pulsed power accelerator working at the voltage of 625 kV, which was guided by an axial magnetic field of 1.05 T and transported through the beam-wave interaction structures. After careful calibration, the microwave power radiated in the far field was as high as about 500 MW, with a frequency of 32.1 GHz and a pulse width of 20 ns. The radiation mode was well controlled to be TM(0n) mode. PMID:26329220

  15. Resonant energy conversion of 3-minute intensity oscillations into Alfven waves in the solar atmosphere

    E-print Network

    D. Kuridze; T. V. Zaqarashvili

    2007-03-19

    Nonlinear coupling between 3-minute oscillations and Alfven waves in the solar lower atmosphere is studied. 3-minute oscillations are considered as acoustic waves trapped in a chromospheric cavity and oscillating along transversally inhomogeneous vertical magnetic field. It is shown that under the action of the oscillations the temporal dynamics of Alfven waves is governed by Mathieu equation. Consequently, the harmonics of Alfven waves with twice period and wavelength of 3-minute oscillations grow exponentially in time near the layer where the sound and Alfven speeds equal. Thus the 3-minute oscillations are resonantly absorbed by pure Alfven waves near this resonant layer. The resonant Alfven waves may penetrate into the solar corona taking energy from the chromosphere. Therefore the layer c_s=v_A may play a role of energy channel for otherwise trapped acoustic oscillations.

  16. Direct and inverse cascades of energy, momentum and wave action in spectra of wind-driven waves

    NASA Astrophysics Data System (ADS)

    Badulin, S. I.; Pushkarev, A. N.; Resio, D.; Zakharov, V. E.

    2003-04-01

    The time-dependent, spatially uniform Hasselmann's kinetic equation for surface gravity waves in presence of wind forcing and white-capping dissipation is studied numerically. We use conventional parameterizations of wind wave input (Snyder et al. 1981; Plant 1982; Hsiao &Shemdin 1983; Donelan, Pierson 1987) that are consistent with weakly nonlinear scaling. We assume that strong dissipation due to white-capping is essential for short waves only (with frequencies above 1Hz) belonging to the spectral tail and can be neglected near the spectral peak. We compare our numerical results with the predictions of the theory of weak turbulence and found a very good coincidence. It is shown that asymptotic behavior of wave spectra is in perfect agreement with stationary solutions of the Hasselmann equation -- Kolmogorov's solutions for direct (Zakharov & Filonenko 1966) and inverse (Zakharov &Zaslavskii 1982) cascades. This asymptotic behavior appears at rather early stages of wind wave evolution (physical time of order of few hours in our experiments); A strong tendency of solutions to self-similar behavior of duration limited solutions is found for rather wide range of initial conditions and external forcing; Good quantitative coincidence with recapitulative experimental data for duration limited wind wave growth (Young 1999, p.111) and for fetch-limited (JONSWAP) spectra parameterized by wave age C_p/Uwind is found. The findings here are quite robust and hopefully will be applied to the practical problems. Present wave prediction models are based on fairly crude parameterizations of the nonlinear energy transfers. In large part due to inaccuracies in these parameterizations, these models have had to rely on empirical fitting of general growth equation as a basis for constraining additional source-sink terms in the detailed balance equations. Results from this study could be used to reformulate a complete energy balance equation for wave generation, propagation and decay, which could lead to substantially improved predictions in the near future. The research was conducted under the U.S. Army Corps of Engineers, RDT&E program, grant DACA 42-00-C0044, ONR grant N00014-98-1-0070 and NSF grant NDMS0072803, INTAS grant 01-234 and Russian Foundation for Basic Research 01-05-64603, 01-05-64464, 02-05-65140. This support is gratefully acknowledged.

  17. Triboelectric Charging at the Nanostructured Solid/Liquid Interface for Area-Scalable Wave Energy Conversion and Its Use in Corrosion Protection.

    PubMed

    Zhao, Xue Jiao; Zhu, Guang; Fan, You Jun; Li, Hua Yang; Wang, Zhong Lin

    2015-07-28

    We report a flexible and area-scalable energy-harvesting technique for converting kinetic wave energy. Triboelectrification as a result of direct interaction between a dynamic wave and a large-area nanostructured solid surface produces an induced current among an array of electrodes. An integration method ensures that the induced current between any pair of electrodes can be constructively added up, which enables significant enhancement in output power and realizes area-scalable integration of electrode arrays. Internal and external factors that affect the electric output are comprehensively discussed. The produced electricity not only drives small electronics but also achieves effective impressed current cathodic protection. This type of thin-film-based device is a potentially practical solution of on-site sustained power supply at either coastal or off-shore sites wherever a dynamic wave is available. Potential applications include corrosion protection, pollution degradation, water desalination, and wireless sensing for marine surveillance. PMID:26154990

  18. Optimal Power Cost Management Using Stored Energy in Data Centers

    E-print Network

    Giles, C. Lee

    Optimal Power Cost Management Using Stored Energy in Data Centers Rahul Urgaonkar, Bhuvan Urgaonkar of uninterrupted power supply (UPS) units as energy storage devices. This rep- resents a deviation from the usual, making it attractive in the presence of workload and pricing uncertainties. An inter- esting feature

  19. Heightened Delta Power during Slow-Wave-Sleep in Patients with Rett Syndrome Associated with Poor Sleep Efficiency

    PubMed Central

    Ammanuel, Simon; Chan, Wesley C.; Adler, Daniel A.; Lakshamanan, Balaji M.; Gupta, Siddharth S.; Ewen, Joshua B.; Johnston, Michael V.; Marcus, Carole L.; Naidu, Sakkubai; Kadam, Shilpa D.

    2015-01-01

    Sleep problems are commonly reported in Rett syndrome (RTT); however the electroencephalographic (EEG) biomarkers underlying sleep dysfunction are poorly understood. The aim of this study was to analyze the temporal evolution of quantitative EEG (qEEG) biomarkers in overnight EEGs recorded from girls (2–9 yrs. old) diagnosed with RTT using a non-traditional automated protocol. In this study, EEG spectral analysis identified high delta power cycles representing slow wave sleep (SWS) in 8–9h overnight sleep EEGs from the frontal, central and occipital leads (AP axis), comparing age-matched girls with and without RTT. Automated algorithms quantitated the area under the curve (AUC) within identified SWS cycles for each spectral frequency wave form. Both age-matched RTT and control EEGs showed similar increasing trends for recorded delta wave power in the EEG leads along the antero-posterior (AP). RTT EEGs had significantly fewer numbers of SWS sleep cycles; therefore, the overall time spent in SWS was also significantly lower in RTT. In contrast, the AUC for delta power within each SWS cycle was significantly heightened in RTT and remained heightened over consecutive cycles unlike control EEGs that showed an overnight decrement of delta power in consecutive cycles. Gamma wave power associated with these SWS cycles was similar to controls. However, the negative correlation of gamma power with age (r = -.59; p<0.01) detected in controls (2–5 yrs. vs. 6–9 yrs.) was lost in RTT. Poor % SWS (i.e., time spent in SWS overnight) in RTT was also driven by the younger age-group. Incidence of seizures in RTT was associated with significantly lower number of SWS cycles. Therefore, qEEG biomarkers of SWS in RTT evolved temporally and correlated significantly with clinical severity. PMID:26444000

  20. A Stochastic Power Network Calculus for Integrating Renewable Energy Sources into the Power Grid

    SciTech Connect

    Wang, K; Ciucu, F; Lin, C; Low, SH

    2012-07-01

    Renewable energy such as solar and wind generation will constitute an important part of the future grid. As the availability of renewable sources may not match the load, energy storage is essential for grid stability. In this paper we investigate the feasibility of integrating solar photovoltaic (PV) panels and wind turbines into the grid by also accounting for energy storage. To deal with the fluctuation in both the power supply and demand, we extend and apply stochastic network calculus to analyze the power supply reliability with various renewable energy configurations. To illustrate the validity of the model, we conduct a case study for the integration of renewable energy sources into the power system of an island off the coast of Southern California. In particular, we asses the power supply reliability in terms of the average Fraction of Time that energy is Not-Served (FTNS).