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1

Energy analysis of wave and tidal power  

NASA Astrophysics Data System (ADS)

Energy requirements for building wave- and tidal-power systems are estimated and the relationship between energy requirements and extraction efficiency is examined for wavepower systems. It is found that a point of maximum net output is reached, beyond which further increases in extraction efficiency result in decreased net energy. In this manner, the energy analysis identifies a limit on the energy which could, in principle, be extracted by a wave-energy system. Finally, it is noted that although similar limits could be identified for other types of energy sources, the tidal power analysis is confined to a brief comparison of energy inputs and outputs.

Harrison, R.; Smith, K. G.; Varley, J. S.

1980-06-01

2

Power electronic grid-interface for renewable ocean wave energy  

Microsoft Academic Search

This paper presents information on ocean wave energy converters and power electronics grid-interface. In the introduction a basic terms and methods of ocean wave energy capture are discussed. Further several most important ocean wave energy conversion prototypes are briefly described. The generators and power electronics solutions for Power Take Off (PTO) system are presented on the example of Wave Dragon

Marian P. Kazmierkowski; Marek Jasinski

2011-01-01

3

Grid power integration technologies for offshore ocean wave energy  

Microsoft Academic Search

In this paper, the advanced electric technologies for grid power integration of different offshore wave energy conversion devices are presented. The electrical connection configurations for integrating the electric power of the multi wave energy conversion devices such as the Oscillating Water Column, Pelamis, the Wave Point Absorbers and the Wave Dragon are developed by employing the most efficient low cost

Tarek Ahmed; Katsumi Nishida; Mutsuo Nakaoka

2010-01-01

4

Wave energy converters and their impact on power systems  

Microsoft Academic Search

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

Henk Polinder; Mattia Scuotto

2005-01-01

5

Ocean wave energy based power plant for Sandwip, Bangladesh  

Microsoft Academic Search

As the generated electric power is not enough for the demand of Bangladesh, ocean wave energy can provide a suitable low cost and permanent solution. A promising new technology in this field is a specific wave energy generator which has recently started operation in Europe. The device floats on the ocean water and extracts energy from the waves which causes

Farhaan Fowze; Sarah Amir; Kashfia Quader Khan; Rubiya Binte Mustafiz; Fahim Arefin Khandker

2012-01-01

6

Modeling the Buoyancy System of a Wave Energy Power Plant  

Microsoft Academic Search

A nonlinear dynamic model of the buoyancy system in a wave energy power plant is presented. The plant (“Wave Dragon”) is a\\u000a floating device using the potential energy in overtopping waves to produce power. A water reservoir is placed on top of the\\u000a WD, and hydro turbines lead the water to the sea producing electrical power. Through air chambers it

Tom Søndergaard Pedersen; Kirsten Mølgaard Nielsen

7

Maximum Power Point Tracking for Ocean Wave Energy Conversion  

Microsoft Academic Search

Many forms of renewable energy exist in the world's oceans, with ocean wave energy showing great potential. However, the ocean environment presents many challenges for cost-effective renewable energy conversion, including optimal control of a wave energy converter (WEC). This paper presents a maximum power point tracking (MPPT) algorithm for control of a point absorber WEC. The algorithm and testing hardware

Ean A. Amon; Ted K. A. Brekken; Alphonse A. Schacher

2012-01-01

8

Tapping ocean wave energy for powering gas turbine plants  

Microsoft Academic Search

A new device invented by M. Tornabene of the Amanda Machinery Co. converts random wave action into mechanical or electrical power. In combination with gas turbine\\/generators, it makes for an extremely efficient peaking plant and, with provision for energy storage during off-hours (possibly through water electrolysis for hydrogen production), for a baseload power plant. The device offers low cost, long

LaStella

1975-01-01

9

Wind-wave power available to a wave energy converter array  

Microsoft Academic Search

A theoretical analysis of the wave power available to a line array of wave energy conversion devices is presented. The Pierson-Neumann-James directional spectrum for deep water is used to model the random sea. The present theory predicts 3\\/4 of the maximum power predicted by the former theory that neglected the directionality of the power. The maximum power occurs when the

M. E. McCormick

1978-01-01

10

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

SciTech Connect

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.

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

2012-10-29

11

Power inversion design for ocean wave energy harvesting  

NASA Astrophysics Data System (ADS)

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

Talebani, Anwar N.

12

WAVE POWER INTEGRATION WITH A RENEWABLE HYDROGEN ENERGY SYSTEM  

Microsoft Academic Search

In British Columbia, approximately 90% of the electricity generated comes from hydroelectric facilities while another abundant and renewable resource, ocean wave energy, is not being utilized at all. Technologies exist that can capture and convert wave energy but there are few studies examining systemic integration of wave energy devices. This work examines the potential to use wave energy as an

P. Wild; A. Rowe

13

Wave power statistics for individual waves  

Microsoft Academic Search

The paper provides a bivariate distribution of wave power and wave height, as well as a bivariate distribution of wave power and wave period; both bivariate distributions are for individual waves within a sea state. This is relevant for e.g. making assessments of wave power devices and their potential for converting energy from waves. The results can be applied to compare

Dag Myrhaug; Bernt J. Leira; Håvard Holm

2009-01-01

14

Wind, Wave, and Tidal Energy Without Power Conditioning  

NASA Technical Reports Server (NTRS)

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

Jones, Jack A.

2013-01-01

15

Ocean wave power  

Microsoft Academic Search

The potential of wave power and some of the more promising methods of harnessing it are discussed with attention to the wave energy arriving on the west coast of the United Kingdom. Unresolved technical and engineering problems are examined, and the impact of wave power on the environment is considered. Data on wave power and its variability are supplied. It

I. Glendenning

1977-01-01

16

The potential for grid power integration of offshore ocean wave energy in the UK  

Microsoft Academic Search

In this paper, the advanced electric technologies for grid power integration of different offshore wave energy conversion devices are presented. The electrical connection configurations for integrating the electric power of the multi wave energy conversion devices such as the Oscillating Water Column, Pelamis, the Wave Point Absorbers and the Wave Dragon are developed by employing the most efficient low cost

T. Ahmed; K. Nishida; M. Nakaoka

2010-01-01

17

A dynamic model for control purposes of a wave energy power plant buoyancy system  

Microsoft Academic Search

In order to obtain a control system for a wave energy power plant a linear dynamic model of the buoyancy system is presented. The plant ¿Wave Dragon¿ is a floating device using the potential energy in overtopping waves to produce power. A water reservoir is placed on top of the Wave Dragon, and hydro turbines lead the water to the

Kirsten Moelgaard Nielsen; Tom Soendergaard Pedersen

2009-01-01

18

Wave power—Sustainable energy or environmentally costly? A review with special emphasis on linear wave energy converters  

Microsoft Academic Search

Generating electricity from waves is predicted to be a new source of renewable energy conversion expanding significantly, with a global potential in the range of wind and hydropower. Several wave power techniques are on the merge of commercialisation, and thus evoke questions of environmental concern. Conservation matters are to some extent valid independent of technique but we mainly focus on

Olivia Langhamer; Kalle Haikonen; Jan Sundberg

2010-01-01

19

Ocean waves: power unlimited  

Microsoft Academic Search

After a brief discussion of the types of wave power converters being developed and some technical problems involved in development, 144 bibliographic citations are listed for works on ocean wave energy conversion. (LEW)

Lockerby

1981-01-01

20

Power from ocean waves  

Microsoft Academic Search

The total power of the waves breaking against the world's shores is estimated at 10¹³ watts--the equivalent of world energy consumption. Yet recent research in Britain projects a negative near term future. Performance and costs of wave power devices compared unfavorably to electricity. Studies continue on harnessing wave power at special sites, usually islands, where the waves are energetic, and

1983-01-01

21

Ocean wave power available to submerged energy devices of finite dimensions  

Microsoft Academic Search

The feasibility of deploying wave energy converters at offshore sites near coastal population centers depends upon many factors. Some of the factors to be considered include preliminary power estimates for site selection, converter design, mooring or restraining problems and power transmission to shore. The accuracy of the preliminary wave power estimates depends upon the accuracy and extent of the site

J. M. Niedzwecki

1979-01-01

22

A novel maximum power point tracking algorithm for ocean wave energy devices  

Microsoft Academic Search

Many forms of renewable energy exist in the world's oceans, with ocean wave energy showing great potential. However, the ocean environment presents many challenges for cost-effective renewable energy conversion, including optimal control of a wave energy converter (WEC). This paper presents a novel maximum power point tracking (MPPT) algorithm for control of a point absorber WEC. The algorithm and control

Ean A. Amon; Alphonse A. Schacher; Ted K. A. Brekken

2009-01-01

23

Power from Ocean Waves.  

ERIC Educational Resources Information Center

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

Newman, J. N.

1979-01-01

24

Wave power technologies  

Microsoft Academic Search

The oceans contain a vast amount of mechanical energy in form of ocean waves and tides. The high density of oscillating water results in high energy densities, making it a favorable form of hydro power. The total U.S. available incident wave energy flux is about 2,300 TWh\\/yr. The DOE Energy Information Energy (EIA) estimates 2003 hydroelectric generation to be about

M. Previsic

2005-01-01

25

EXPERIMENTAL TYPE OF AN ECOLOGICAL POWER STATION BASED ON THE ENERGY OF SEA WAVES  

Microsoft Academic Search

Experimental type of the sea ecological power station handled in this research task follow the acquiring electric energy and different forms of energy through: picking up and transforming waves energy in alternative rectilinear movement and converting it to rotation movement, and afterwards in electric energy; transforming alternative movement of swimmers in pneumatic energy and straight in electric energy; obtaining clean

Maria MOISE; Carmen Cristiana BUCUR; Silvia Adina CRISTEA

26

A power analysis and data acquisition system for ocean wave energy device testing  

Microsoft Academic Search

In the testing of ocean wave energy devices, the demand for a portable and robust data acquisition and electrical loading system has become apparent. This paper investigates the development of a 30 kW inclusive system combining loading capabilities, real-time power analysis, and data acquisition for the testing of deployed ocean wave energy devices. Hardware results for ocean testing are included.

Ean Amon; Ted K. A. Brekken; Annette von Jouanne

2011-01-01

27

A Power Analysis and Data Acquisition System for Ocean Wave Energy Device Testing  

Microsoft Academic Search

In the testing of ocean wave energy devices, the demand for a portable and robust data acquisition and electrical loading system has become apparent. This paper investigates the development of an inclusive system combining loading capabilities, real-time power analysis, and data acquisition for the testing of deployed ocean wave energy devices.

E. Amon; T. K. A. Brekken; A. von Jouanne

2009-01-01

28

Convert Low Frequency Energy from Wave Power Plant to High Frequency Energy in Linear Electrical Generator with Gas Springs  

Microsoft Academic Search

This paper describes the concept on conversion of the movement of a float in a wave power plant, characterize by high force and low speed energy, to a high speed and low force energy in linear machine by using gas springs. In a wave power plant the float is moving slowly. The buoyancy force on the float from the raising

R. B. Ummaneni; J. E. Brennvall; R. Nilssen

2008-01-01

29

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

E-print Network

-- In last decades, renewable energy resources are considered as an alternative energy resource to the World alternative or renewable energy sources is becoming a necessity. Among renewable energy harvestingA Predictive power control of Doubly Fed Induction Generator for Wave Energy Converter in Irregular

Brest, Université de

30

Wave power systems  

Microsoft Academic Search

Ocean wave power was investigated as a usable, renewable, alternative energy source. The results suggest that both Salter cams and Cockerell rafts can be designed to convert wave motion to relative mechanical motion and mechanical forces. Mooring problems and costs suggest that Salter cams will be much more expensive than Cockerell rafts. A major problem is converting the available mechanical

N. Doelling

1979-01-01

31

The Wave Power Group  

NSDL National Science Digital Library

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

32

Impact of control strategies on the rating of electric power take off for Wave Energy conversion  

Microsoft Academic Search

In Wave Energy Converters (WECs) the maximum power extraction would be achievable at the expense of a very high rating of the electric and power electronics equipment. The goal of this paper is to show how a convenient trade-off between high power extraction and viable electrical device ratings can be achieved by a proper choice of the WEC control strategy.

E. Tedeschi; M. Molinas

2010-01-01

33

Modeling and Control of AWS-Based Wave Energy Conversion System Integrated Into Power Grid  

Microsoft Academic Search

In this paper, the model of Archimedes wave swing (AWS) based wave energy conversion (WEC) system is proposed where a new coordinate transformation for the linear permanent magnet generator between the abc frame of reference and the dq0 frame of reference is proposed and the model of the LPMG in dq0 reference frame suitable for power system dynamic and stability

Feng Wu; Xiao-Ping Zhang; Ping Ju; Michael J. H. Sterling

2008-01-01

34

Low-power autonomous wave energy capture device for remote sensing and communications applications  

Microsoft Academic Search

Ocean remote sensing techniques often rely on autonomous buoys to measure and transmit real-time oceanographic and meteorological data. The operating lifetime, payload capacity, and sampling rate of such platforms are limited by onboard battery power. Here, we describe a rotary-drive, wave energy conversion device which utilizes the heaving motion of a surface buoy to generate power over a broad range

Deanelle Symonds; E. Davis; R. C. Ertekin

2010-01-01

35

Minimising capacitor lifetime failures in power converters for wave energy applications  

Microsoft Academic Search

The offshore location of wave energy converters demands a highly reliable and fault-tolerant system. Capacitors account for the majority of failures in power converters and should be replaced prior to failure to reduce system downtime. This paper presents a control methodology to reduce the rate of capacitor degradation as a means to improve fault tolerance. Modeling, simulation, and power converter

Jonathan K. H. Shek; D. Ewen Macpherson; Markus A. Mueller

2011-01-01

36

Calibration of power and energy meters for the far infrared/near millimeter wave spectral region  

SciTech Connect

Power and energy measurements in the sub-mm/near-mm wave spectral region are assuming greater importance as experimentation and data exchange increases. Much of the information on power and energy measurements of lasers and other sources is derived from common detectors constructed for operation at visible and near infrared wavelengths. This paper reports on recent progress in attempts to provide accurate calibrations for instruments such as pyroelectrics and calorimeters in the 40 micron to 3 mm spectral region.

Foote, F.B.; Hodges, D.T.; Dyson, H.B.

1981-07-01

37

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

Microsoft Academic Search

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

Ross Henderson

2006-01-01

38

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

SciTech Connect

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.

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

2012-04-01

39

Useful power from ocean waves  

Microsoft Academic Search

Requirements for an ocean-wave power generator are stipulated and a novel concept to meet those requirements, based on submerged pressure transducer system, is described and discussed. A comparison between solar, wind and ocean-wave energy density is given. Calculations for 24 hour periods indicate that ocean-wave energy posesses the highest energy density per unit area - seven times more than solar

M. Semo

1978-01-01

40

Wave action power plant  

Microsoft Academic Search

A wave action power plant powered by the action of water waves has a drive shaft rotated by a plurality of drive units, each having a lever pivotally mounted on and extending from said shaft and carrying a weight, in the form of a float, which floats on the waves and rocks the lever up and down on the shaft.

Lucia

1982-01-01

41

Water wave energy transducer  

Microsoft Academic Search

A water wave energy transducer for converting the motion of a water wave into a controlled mechanical movement such as rotational motion suitable for actuating an electrical generator is disclosed. The transducer comprises a float member floatingly moored in a water body having waves and\\/or tidal movement, such as a seashore. A power gear is rotatably mounted in a swing

Lamberti

1980-01-01

42

Wave driven power generators  

Microsoft Academic Search

Two one-way clutches on a power output shaft are driven through two oppositely driven power trains driven by a lever arm oscillated by a float raised by waves and lowered by gravity. In an alternate embodiment, a plurality of floatoscillated lever arms are spaced apart a fraction of a wave length and drive pairs of one-way clutches on a power

Neville

1975-01-01

43

Waves of energy  

SciTech Connect

Possible means for harnessing the energy contained in ocean waves are considered. Problems associated with the low-grade nature of wave energy and the rate at which wave crests approach are pointed out, and simple devices already in use for the supply of energy to bell buoys, whistle buoys and lighted buoys are noted. Attention is then given to wave energy conversion systems based on the focusing of waves onto a narrow ramp leading to a reservoir from which water is released to power a turbine generator: a slightly submerged circular shell which directs waves into its center cavity where waves act to turn a turbine (the Dam-Atoll), a long vertical pipe with an internal valve allowing water to move in an upward direction (the Isaacs wave-energy pump), a turbine located at the bottom of an open-topped pipe (the Masuda buoy), a completely submerged closed air chamber from which runs a large pipe open to the sea, a wave piston which acts by the compression of air to drive a turbine, a massive structure with upper and lower reservoirs (the Russel rectifier), and devices which consist of floating or submerged objects which transfer wave energy to pumps (the Salter duck and Cockerell raft). It is concluded that although wave-powered generators are not likely to become competitive in the near future or provide more than a small portion of world demand, they may be found useful under special conditions.

Smith, F.G.W.; Charlier, R.H.

1981-05-01

44

Cycloidal Wave Energy Converter  

SciTech Connect

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.

Stefan G. Siegel, Ph.D.

2012-11-30

45

Production simulator for wave power plants  

Microsoft Academic Search

The report gives plans and specifications for a wave power production simulator. The simulator is a computer program that computes how much of the energy in the open ocean that can be converted to usable energy at a site off or onshore. The production of wave power from sea waves is not an easy task. Efforts have been made in

K. Torsethaugen

1994-01-01

46

Wave-energy converter  

Microsoft Academic Search

The invention provides a device for converting wave energy into useful work, and comprises a body adapted to be moved to and fro by waves on a liquid, and means such as a hydraulic piston in a cylinder for converting this movement of the body into a power output. The body may be disposed about a horizontal cable along which

1985-01-01

47

Wave-energy converter  

Microsoft Academic Search

The invention provides a device for converting wave energy into useful work, and comprises a body adapted to be moved to and fro by waves on a liquid, and means such as a hydraulic piston in a cylinder for converting this movement of the body into a power output. The body may be disposed about a horizontal cable along which

1982-01-01

48

Wave Power Demonstration Project at Reedsport, Oregon  

SciTech Connect

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.

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

2013-10-21

49

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

E-print Network

is achieved with a rotor current controller. Gear Auxiliary Drives Brake DFIGDFIG Frequency Converter Wave Energy Converter Control Main Circuit Breaker Medium Voltage Switchgear Line Coupling Transformer Gear Auxiliary Drives Brake DFIGDFIG Frequency Converter Wave Energy Converter Control Main Circuit Breaker

Paris-Sud XI, Université de

50

Wave action power plant  

SciTech Connect

A wave action power plant powered by the action of water waves has a drive shaft rotated by a plurality of drive units, each having a lever pivotally mounted on and extending from said shaft and carrying a weight, in the form of a float, which floats on the waves and rocks the lever up and down on the shaft. A ratchet mechanism causes said shaft to be rotated in one direction by the weight of said float after it has been raised by wave and the wave has passed, leaving said float free to move downwardly by gravity and apply its full weight to pull down on the lever and rotate the drive shaft. There being a large number of said drive units so that there are always some of the weights pulling down on their respective levers while other weights are being lifted by waves and thereby causing continuous rotation of the drive shaft in one direction. The said levers are so mounted that they may be easily raised to bring the weights into a position wherein they are readily accessible for cleaning the bottoms thereof to remove any accumulation of barnacles, mollusks and the like. There is also provided means for preventing the weights from colliding with each other as they independently move up and down on the waves.

Lucia, L.V.

1982-03-16

51

Harnessing the power of the waves  

SciTech Connect

Norway and several other countries have harnessed the enormous energy of the ocean and used it to produce electric energy. Norway's first wave-power station is at Tostestallen and has two types of wave-energy power plants. The first is an oscillating column generator which uses the force of the waves to push air up a 65 foot tower and through a turbine which drives a generator. As the wave recedes, the air is sucked back through the turbine, which runs continuously. The second power plant uses wave water that spills over a dam into a reservoir and rushes through turbines as it flows back to the sea. Norwegian engineers are also experimenting with ways to focus waves by creating a lens shaped reef. Ocean wave power technology could be useful to isolated places which have no other source of electric power, like the Marshall Islands of the Pacific.

Not Available

1987-04-01

52

Control of an oscillating-water-column wave power plant for maximum energy production  

Microsoft Academic Search

A stochastic model was applied to devise an optimal algorithm for the rotational speed control of an oscillating-water-column (OWC) wave power plant equipped with a Wells turbine and to evaluate the average power output of the plant. The hydrodynamic coefficients for the OWC are assumed known (as functions of frequency), as well as the turbine performance curves. The whole model

A. F. de O Falcão

2002-01-01

53

Electromagnetic wave energy converter  

NASA Technical Reports Server (NTRS)

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.

Bailey, R. L. (inventor)

1973-01-01

54

Hydrostatic transmission development for wave energy converters  

Microsoft Academic Search

innovative approach for electric power conversion from the vast ocean wave energy. Here, a floating-buoy wave energy converter (WEC) using hydrostatic transmission (HST), which is shortened as HSTWEC, is proposed and designed to enhance the wave energy generation task during wave fluctuations. In this HSTWEC structure, the power take-off system (PTO) is a combination of the designed HST circuit and

Hoang Huu Tien; Dinh Quang Truong; Kyoung Kwan Ahn

2011-01-01

55

An innovative design of wave energy converter  

Microsoft Academic Search

The aim of this research is to develop an innovative approach for electric power conversion of the vast ocean wave energy. A floating-buoy wave energy converter (WEC) using hydrostatic transmission (HST), which is shortened as HSTWEC, has been proposed to enhance the wave energy generation from wave fluctuations. In the HSTWEC device, the power take-off system (PTO) was combined with

K. K. Ahn; D. Q. Truong; Hoang Huu Tien; Jong Il Yoon

56

Wave power estimates utilizing ocean wave spectra  

Microsoft Academic Search

A complete formulation of the spectral wave power equations, based upon linear wave theory, to be used with one-dimensional and directional sea spectrum are presented. These equations are quite general and allow for the specification of device specific information, such as, the wave capture\\/conversion efficiency and vertical projected capture height. Previously published field data is used to emphasize that the

John M. Niedzwecki

1983-01-01

57

Ball screw type wave power generator  

Microsoft Academic Search

To obtain an even flow of electric power form fluctuating wave energy, the authors devised a ball screw type wave power generator (BSTWPG) which consists of a pressure plate, ball screws and nuts, one-way clutches, flywheels and generators. The equations of motion of the BSTWPG system are shown and the digital simulation using Continuous System Simulation Language is developed on

K.-I. Ohmata; H. Shimoda

1979-01-01

58

Wave profile prediction and wave power forecasting by using wind statistics  

Microsoft Academic Search

There are different types of ocean waves but among them wind generated waves have the highest energy concentration. The power in a wave is proportional to the square of amplitude and period of the wave. And the amplitude and period is related to wind speed. When enough wave observations are available, it is possible to determine the wave power directly

Aminul Hoque

2012-01-01

59

The effect of wave period filtering on wave power extraction and device tuning  

Microsoft Academic Search

The variations in the quantity of wave power available to a wave energy converter by filtering out short-period waves have been examined in this paper. Ocean wave data recorded at three different locations and water depths around northern Europe are used for this purpose along with numerically synthesized wave time series. A wave power ratio, defined as the ratio between

Vengatesan Venugopal; George H. Smith

2007-01-01

60

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

SciTech Connect

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

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

2013-12-07

61

The Promise of Wave Power (Invited)  

NASA Astrophysics Data System (ADS)

The solutions to today's energy challenges need to be explored through alternative, renewable and clean energy sources to enable diverse energy resource plans. An extremely abundant and promising source of energy exists in the world's oceans: it is estimated that if 0.2 % of the oceans' untapped energy could be harnessed, it could provide power sufficient for the entire world. Ocean energy exists in the forms of wave, tidal, marine currents, thermal (temperature gradient) and salinity. Among these forms, significant opportunities and benefits have been identified in the area of ocean wave energy extraction, i.e., harnessing the motion of the ocean waves, and converting that motion into electrical energy. Ocean wave energy refers to the kinetic and potential energy in the heaving motion of ocean waves. Wave energy is essentially concentrated solar energy (as is wind energy). The heating of the earth’s surface by the sun (with other complex processes) drives the wind, which in turn blows across the surface of the ocean to create waves. At each stage of conversion, the power density increases. Ocean wave power offers several attractive qualities, including high power density, low variability, and excellent forecastability. A typical large ocean wave propogates at around 12 m/s with very little attenuation across the ocean. If the waves can be detected several hundred kilometers off shore, there can be 10 hours or more of accurate forecast horizon. In fact, analysis has shown good forecast accuracy up to 48 hours in advance. Off the coast Oregon, the yearly average wave power is approximately 30 kW per meter of crestlength (i.e., unit length transverse to the direction of wave propagation and parallel to the shore.) This compares very favorably with power densities of solar and wind, which typically range in the several hundreds of Watts per square meter. Globally, the wave energy resource is stronger on the west coasts of large landmasses and increases in strength toward the poles. This phenomenon is due to the prevailing west to east global winds known as the "westerlies" found in the Northern and Southern hemispheres between 30 and 60 degrees latitude. Correspondingly, the west coast of the United States, the west coast of Australia, and the coastal regions of Europe have seen the greatest wave energy industrial activity to date. Ocean wave energy has great potential to be a significant contributor of renewable power for many regions in the world. For the West coast of the US alone, the total wave energy resource is estimated at 440 TWh/yr, which is more than the typical total US annual hydroelectric production (270 TWh in 2003). For US west coast states, a fully developed wave energy industry could be a significant contributor to renewable energy portfolio standards. Within the next few years, several utility-scale wave energy converters are planned for grid connection (e.g., Ocean Power Technologies and Columbia Power Technologies in Oregon, USA), with plans for more utility-scale development to follow soon after. This presentation will cover the physical basics of wave energy, examples of commercial technology, challenges opportunities for research, and an update on the wave energy research and developments at leading commercial, industrial, and academic institutions around the world.

Brekken, T.

2010-12-01

62

A Methodology for Large-Scale Ocean Wave Power Time-Series Generation  

Microsoft Academic Search

Ocean wave power is characterized by high power density, and wave forecasts can predict incident wave energy days in advance. These qualities make ocean wave power a promising renewable energy source. In the near future, utility-scale wave energy conversion arrays will likely be installed. However, little is currently known on the impact of large wave energy conversion (WEC) facilities on

Ted K. A. Brekken; H. Tuba Ozkan-Haller; Asher Simmons

2012-01-01

63

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

NASA Astrophysics Data System (ADS)

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.

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

2014-04-01

64

Offshore wave power measurements—A review  

Microsoft Academic Search

The first wave power patent was filed in 1799. Since then, hundreds of ideas for extraction of energy from ocean waves have surfaced. In the process of developing a concept, it is important to learn from previous successes and failures, and this is not least important when moving into the ocean. In this paper, a review has been made with

Simon Lindroth; Mats Leijon

2011-01-01

65

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

PubMed

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

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

2011-07-28

66

Direct Mechanical Conversion of Ocean Wave Energy  

Microsoft Academic Search

Recently wave energy conversion has attracted renewed interest from governments and developers looking for alternative carbon free energy resources. Ocean waves have been shown to contain large quantities of power. However, it has proven very difficult to capture even a fraction of this energy in real ocean conditions. This paper reviews the complex energy flows associated with ocean waves and

L. Le-Ngoc; A. I. Gardiner

67

Feasibility of a multidimensional wave energy harvester  

Microsoft Academic Search

Wave motions represent a source of substantial untapped energy. Given the current interest in renewable power, research continues into the development of wave energy harvesting devices. An evaluation of existing wave energy harvester designs has shown that there are a number of different methods typically used to carry out the mechanical-to-electrical energy conversion process. A common observation is that existing

Anthony Fowler; Sam Behrens

2010-01-01

68

Estimating the potential of ocean wave power resources  

Microsoft Academic Search

The realistic assessment of an ocean wave energy resource that can be converted to an electrical power at various offshore sites depends upon many factors, and these include estimating the resource recognizing the random nature of the site-specific wave field, and optimizing the power conversion from particular wave energy conversion devices. In order to better account for the uncertainty in

Amir H. Izadparast; John M. Niedzwecki

2011-01-01

69

Production simulator for wave power plants  

NASA Astrophysics Data System (ADS)

The report gives plans and specifications for a wave power production simulator. The simulator is a computer program that computes how much of the energy in the open ocean that can be converted to usable energy at a site off or onshore. The production of wave power from sea waves is not an easy task. Efforts have been made in several countries to develop devices that can extract energy from the ocean, but very few have so far been successful. During the last 15 years a considerable know-how has been established in Norway on wave energy utilization. Part of this know-how will be included in the proposed production simulator. Evaluation of new devices and new sites can be done in a more comparative and efficient way by this tool. It will contribute to interdisciplinary activity in the field of wave power utilization, and should be applicable for the nonexpert. The simulator consists of several modules, joined together by computer software. The plans so far include purpose, needs and background for the development of a wave power plant simulator and a high level specification of the software and scope of work.

Torsethaugen, K.

1994-07-01

70

Ocean wave energy harvesting buoy for sensors  

Microsoft Academic Search

Methodology and results are presented for the numerical simulations and experimental measurements on ocean energy harvesting systems that utilize anchored linear generators, driven by heaving surface buoys that convert ambient ocean wave energy into useful electrical power. The results demonstrate the feasibility of using ocean wave energy harvesting buoys and simple linear generators to provide sufficient electrical power for ocean

Steven P. Bastien; Raymond B. Sepe; Annette R. Grilli; Stephan T. Grilli; Malcolm L. Spaulding

2009-01-01

71

Utilization of the energy in ocean waves  

Microsoft Academic Search

The characteristics of ocean wind waves place certain constraints upon devices designed to convert their energy to a useful form. Here we consider the nature of these constraints and the theoretical analysis of a wave power generator that conforms to the design criteria. We also present the results of field tests with several models of the wave power generator. The

J. D. Isaacs; D. Castel; G. L. Wick

1976-01-01

72

Proposed electromagnetic wave energy converter  

NASA Technical Reports Server (NTRS)

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.

Bailey, R. L.

1973-01-01

73

Wave energy conversion in a random sea  

Microsoft Academic Search

The wind wave power delivered to several hypothetical wave energy converters is predicted using the Pierson-Moskowitz wave spectrum. Two general types of converters are considered: First, the half-plane type which is dependent on wave direction, but not normally dependent on wave frequency. The second type is the omni-directional which is independent of wave direction but normally frequency dependent. Results of

M. E. McCormick

1978-01-01

74

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

E-print Network

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 ...

Li, Bin

2012-11-29

75

Power resource estimate of ocean surface waves  

Microsoft Academic Search

The distribution of wave energy and power as functions of longitude and latitude are presented for the Northern Hemisphere at 12Z, October 2, 1975. Both the large peak of the distribution in the Atlantic Ocean and the smaller peak in the Pacific Ocean are found to be at longitudes towards the eastern end of the ocean basins. This ''eastern accumulation''

N PANICKER

1976-01-01

76

Wave Prediction and Robust Control of Heaving Wave Energy Devices for Irregular Waves  

Microsoft Academic Search

This paper presents a comparison of different existing and proposed wave prediction models applicable to control wave energy converters (WECs) in irregular waves. The objective of the control is to increase the energy conversion. The power absorbed by a WEC is depending on the implemented control strategy. Un- certainties in the physical description of the system as well as in

Marco P. Schoen; Jørgen Hals; Torgeir Moan

2011-01-01

77

Ocean wave power data generation for grid integration studies  

Microsoft Academic Search

Ocean wave power is a promising renewable energy source that offers several attractive qualities, including high power density, low variability, and excellent forecastability. Within the next few years, several utility-scale wave energy converters are planned for grid connection (e.g., Pelamis Power in Portugal and Ocean Power Technologies in Oregon, USA), with plans for more utility-scale development to follow soon after.

Shaun McArthur; Ted K. A. Brekken

2010-01-01

78

Water wave energy transducer  

Microsoft Academic Search

A water wave energy transducer comprises a boat having pivoted arms projecting out over the water, a float being mounted on the outboard end of each arm so that the arms are oscillated by wave action on the floats. Drive sprockets fixed on the arms coaxially with their pivots are connected by drive chains with two driven sprockets coaxial, respectively,

Lamberti

1983-01-01

79

Science Nation: Wave of Discovery: Harnessing the Ocean's Power  

NSDL National Science Digital Library

Capturing the power of ocean waves could become an important part of the world's renewable energy portfolio. Interest and support of this technology has not been consistent. There was enthusiasm after the 1970s oil embargo, but it dropped when oil prices stabilized. Researchers at the Wallace Energy Systems and Renewables Facility (WESRF) in Corvallis, Ore., are at work on wave energy systems. While research in wave energy is 15-20 years behind renewables such as wind power, waves are far more reliable as an energy source. While solar power is only available about 50 percent of the time; and winds are not constant, waves are, and experts say wave energy might one day provide up to six percent of the electricity needs of the United States.

80

Wave energy systems for recharging AUV energy supplies  

Microsoft Academic Search

This paper describes ocean wave energy resources and characterizes their global distribution and temporal variability. It presents an overview of wave energy conversion devices that have progressed beyond the laboratory wave tank and have been proven at sea, and which lend themselves to miniaturization and packaging in a configuration suitable for recharging AUV power supplies from a docking station base.

George Hagerman

2002-01-01

81

Research on energy conversion system of floating wave energy converter  

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

82

Economic feasibility of cam-type wave power generators  

Microsoft Academic Search

Model tests at M.I.T. have indicated that cam-type wave power generator is capable of high efficiencies of energy extraction from ocean waves. This report presents a design methodology for determining costs of energy produced from wave power generators. Feasible designs were developed for ocean locations around the coast of the United States with the resulting breakeven costs with oil ranging

Bisceglia

1978-01-01

83

Characteristics of a rocking wave power device  

Microsoft Academic Search

The results are presented of an investigation concerning the bandwidth of wave periods covered by a device considered by Salter (1974) for extracting a large proportion of the total wave power from water waves. It was found that good power conversion efficiencies (more than 50%) can be obtained over the range of wave periods (a 2:1 bandwidth) corresponding to that

D. T. Swift-Hook; B. M. Count; I. Glendenning; S. Salter

1975-01-01

84

Overview of Ocean Wave and Tidal Energy Lingchuan Mei  

E-print Network

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

Lavaei, Javad

85

Scaled wave energy device performance evaluation through high resolution wave tank testing  

Microsoft Academic Search

This paper presents the high-precision wave tank testing of Columbia Power Technologies' (COLUMBIA POWER's) 1:15 scale wave energy device in Oregon State University's (OSU's) large wave flume. Wave energy converter (WEC) testing in the OSU O.H. Hinsdale Wave Research Laboratory (HWRL), in collaboration with the Northwest National Marine Renewable Energy Center (NNMREC) headquartered at OSU, includes state-of-the-art optical motion tracking

Ken Rhinefrank; Al Schacher; Joe Prudell; Erik Hammagren; Chad Stillinger; David Naviaux; Ted Brekken; Annette von Jouanne

2010-01-01

86

O Electromagnetic Power Waves and Power Density Components.  

NASA Astrophysics Data System (ADS)

On January 10, 1884 Lord Rayleigh presented a paper entitled "On the Transfer of Energy in the Electromagnetic Field" to the Royal Society of London. This paper had been authored by the late Fellow of Trinity College, Cambridge, Professor J. H. Poynting and in it he claimed that there was a general law for the transfer of electromagnetic energy. He argued that associated with each point in space is a quantity, that has since been called the Poynting vector, that is a measure of the rate of energy flow per unit area. His analysis was concerned with the integration of this power density vector at all points over an enclosing surface of a specific volume. The interpretation of this Poynting vector as a true measure of the local power density was viewed with great skepticism unless the vector was integrated over a closed surface, as the development of the concept required. However, within the last decade or so Shadowitz indicates that a number of prominent authors have argued that the criticism of the interpretation of Poynting's vector as a local power density vector is unjustified. The present paper is not concerned with these arguments but instead is concerned with a decomposition of Poynting's power density vector into two and only two components: one vector which has the same direction as Poynting's vector and which is called the forward power density vector, and another vector, directed opposite to the Poynting vector and called the reverse power density vector. These new local forward and reverse power density vectors will be shown to be dependent upon forward and reverse power wave vectors and these vectors in turn will be related to newly defined forward and reverse components of the electric and magnetic fields. The sum of these forward and reverse power density vectors, which is simply the original Poynting vector, is associated with the total electromagnetic energy traveling past the local point. Another vector which is the difference between the forward and reverse power density vectors and which will be shown to be associated with the total electric and magnetic field energy densities existing at a local point will also be introduced. These local forward and reverse power density vectors may be integrated over a surface to determine the forward and reverse powers and from these results problems related to maximum power transfer or efficiency of electromagnetic energy transmission in space may be studied in a manner similar to that presently being done with transmission lines, wave guides, and more recently with two port multiport lumped parameter systems. These new forward and reverse power density vectors at a point in space are analogous to the forward and revoltages or currents and power waves as used with the transmission line, waveguide, or port. These power wave vectors in space are a generalization of the power waves as developed by Penfield, Youla, and Kurokawa and used with the scattering parameters associated with transmission lines, waveguides and ports.

Petzold, Donald Wayne

1980-12-01

87

Enhanced Singular Wave Reactor for Surface Power  

Microsoft Academic Search

The “CANDLE” (Constant Axial shape of Neutron flux, nuclide densities and power shape During Life of Energy producing reactor) also known as singular wave reactor has many significant advantages related to elimination of the need for enrichment. The use of micro-hetero structured fuel, generically called “cer-liq-mesh” will further improve burnup up to 90%. In spite it has typically large dimensions,

L. Popa-Simil

2011-01-01

88

E2I EPRI Assessment Offshore Wave Energy Conversion Devices  

E-print Network

definition study in CY 2004. This study will produce system designs for wave energy conversion device powerE2I EPRI Assessment Offshore Wave Energy Conversion Devices Report: E2I EPRI WP ­ 004 ­ US ­ Rev 1 #12;E2I EPRI Assessment - Offshore Wave Energy Conversion Devices Table of Contents Introduction

89

Ocean Wave Energy Conversion  

Microsoft Academic Search

ABSTRACT Ocean energy conversion has been of interest for many,years. Recent developments,such as concern over global warming,have renewed,interest in the topic. This report focuses on wave energy converters (WEC) as opposed to ocean current energy converters. The point absorber and oscillating water column,WEC devices are addressed with regards tocommercial prospects, environmental concerns, and current state-of-the art. This report also provides

Jennifer Vining

2005-01-01

90

Key features of wave energy.  

PubMed

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

Rainey, R C T

2012-01-28

91

Power recycling for an interferometric gravitational wave  

E-print Network

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

Ejiri, Shinji

92

Hydro-piezoelectric power generation from ocean waves  

Microsoft Academic Search

A new concept is proposed for the large scale generation of electrical power from deep water, ocean wave. The concept is based on using large areas of multi-layered piezoelectric polymers to directly convert, on a contininuous basis, the essentially unlimited mechanical energy present in the ocean waves into high voltage, low frequenc electrical energy.

George W. Taylor; Joseph R. Burns

1983-01-01

93

High power broadband millimeter wave TWTs  

Microsoft Academic Search

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

Bill G. James

1999-01-01

94

High Power Broadband Millimeter Wave TWTs  

Microsoft Academic Search

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

Bill G. James

1998-01-01

95

High power broadband millimeter wave TWTs  

Microsoft Academic Search

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

Bill G. James

1999-01-01

96

Performance of a direct drive hydro turbine for wave power generation  

Microsoft Academic Search

Clean and renewable energy technologies using ocean energy give us non-polluting alternatives to fossil-fueled power plants as a countermeasure against the global warming and growing demand for electrical energy. Among the ocean energy resources, wave power takes a growing interest because of its enormous amount of potential energy in the world. Therefore, various types of wave power system to capture

Y.-H. Lee; C.-G. Kim; Y.-D. Choi; I.-S. Kim; Y.-C. Hwang

2010-01-01

97

Direct Drive Wave Energy Converters  

Microsoft Academic Search

Over the last 25 years there have been numerous proposals for the conversion of energy contained within sea waves into electricity. Despite this fact, there is not yet one definitive wave energy device that stands out from the rest and developments in several concepts still continues. One aspect of a wave energy converter is the manner in which the physical

N. J. Baker; M. A. Mueller

2001-01-01

98

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

PubMed

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

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

2014-01-01

99

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

PubMed Central

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

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

2014-01-01

100

Wave-powered electrolysis of water  

Microsoft Academic Search

An offshore water electrolysis plant which produces pressurized gas by electrolysis of fresh water and wave power includes the combination of a wave-powered electric generator at the ocean surface, an electrolyzer and storage vessels located on the ocean bottom for providing gas under pressure, and a source of fresh water at the ocean surface forced down to the submerged electrolyzer

Lapeyre

1984-01-01

101

Large-scale ocean wave energy plant modeling  

Microsoft Academic Search

In order for wave energy conversion to be a commercially viable technology, wave energy researchers, developers, investors and utilities need an estimate of a wave energy converter's (WEC) power output at a potential installation site. The wind industry has developed generic turbine models that capture the general dynamics of large-scale proprietary wind turbine designs in order to estimate a turbine's

Kelley Ruehl; T. K. A. Brekken; B. Bosma; R. Paasch

2010-01-01

102

Enhanced Singular Wave Reactor for Surface Power  

NASA Astrophysics Data System (ADS)

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

Popa-Simil, L.

103

Wave-PV hybrid generation system carried in the offshore floating type wave power device \\  

Microsoft Academic Search

Japan Agency for Marine-Earth Science and Technology (JAMSTEC) has been engaged in research and development of ocean-wave energy extraction technology for many years now. In particular, work began in 1987 an offshore floating type wave power device called \\

H. Osawa; T. Miyazaki

2004-01-01

104

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...

105

Energy Storage and Generation from Thermopower Waves  

NASA Astrophysics Data System (ADS)

We have demonstrated through simulation and experiment that the nonlinear coupling between an exothermic chemical reaction in a fuel and a nanowire or nanotube with large axial heat conduction accelerates the thermal reaction wave along the nano-conduit. The thermal conduit rapidly transports energy to unreacted fuel regions, and the reaction wave induces a concomitant thermopower wave of high power density, producing electrical current in the same direction. At up to 14 W/g, this can be substantially larger than the power density offered by current micro-scale power sources (e.g. fuel cells, batteries) and even about seven times greater than that of commercial Li-ion batteries. MEMS devices and wireless sensor networks would benefit from such high power density sources to enable functions such as communications and acceleration hampered by present power sources.

Abrahamson, Joel; Mahajan, Sayalee; Choi, Wonjoon; Schonenbach, Nicole; Park, Jungsik; Walsh, Michael; Forman, Jared; Han, Jae-Hee; Kalantar-Zadeh, Kourosh; Strano, Michael

2012-02-01

106

The Effects of Wave Energy Converters on a Monochromatic Wave Climate  

E-print Network

power from the ocean waves [Wilson & Beyene 2007; Beyene & Wilson 2007]. According to a report edited available from the National Oceanic and Atmospheric Administration (NOAA). Wave energy converters were converters as well as the availability of energy in the ocean. This study will examine the effects of a wave

Fox-Kemper, Baylor

107

Multi-objective optimal causal control of an ocean wave energy converter in random waves  

Microsoft Academic Search

In order to maximize the effectiveness of an ocean wave energy converter, its power output must be explicitly regulated via a feedback control system. It is a classical result that when ocean waves are stochastic and the converter's response is linear, the physically-maximal power generation is only obtained using an anticausal feedback law; i.e., one which regulates power based on

J. T. Scruggs

2011-01-01

108

Wave energy: a Pacific perspective.  

PubMed

This paper illustrates the status of wave energy development in Pacific rim countries by characterizing the available resource and introducing the region's current and potential future leaders in wave energy converter development. It also describes the existing licensing and permitting process as well as potential environmental concerns. Capabilities of Pacific Ocean testing facilities are described in addition to the region's vision of the future of wave energy. PMID:22184673

Paasch, Robert; Ruehl, Kelley; Hovland, Justin; Meicke, Stephen

2012-01-28

109

Oceanic wave powered prime mover  

Microsoft Academic Search

A prime mover has a number of bladed rotors supported on a drive shaft over the surface of a wave-generating body of water for rotating the shafts by action of waves against the rotors. Unique planetary gearing assemblies coupling each rotor to the shaft provide necessary torque conversion for rotating the shaft at the desired speed. In preferred forms, the

Comstock

1979-01-01

110

An updated analysis for variable-energy shock waves in a gas-particle two-phase flow: A power series solution  

E-print Network

We present new similarity solutions in the form of power series to describe the propagation of shock waves produced due to a strong explosion in a dusty gas whose energy is deposited or lost at the front. The dusty gas is assumed to be a mixture of a perfect gas and small solid particles, in which solid particles are continuously distributed. The total energy of the flow field behind the shock front is assumed to be time dependent and vary according to E = Eo t^k, where Eo and k are taken as constants. The case of spherical shock waves is worked out in detail to investigate to what extent the flow-field between the shock wave and inner expanding surface or piston is influenced by the presence of small dust particles. The effects due to an increase in (i) the propagation distance from the piston, (ii) the mass concentration of solid particles in the mixture and (iii) the ratio of the density of the solid particles to the initial density of the gas, on the velocity of mixture, pressure of mixture, density of mi...

Anand, R K

2014-01-01

111

Wave Energy challenges and possibilities  

E-print Network

or fixed coastal installation. Air based Wells turbines as power take off. Over topping waves into a reservoir, with low head turbines as power take off. Articulating tubes with hydraulic power take off. Point and standard offshore - and wind turbine technology. It is scalable into multi MW converters. Price

112

High power millimeter wave source development program  

NASA Technical Reports Server (NTRS)

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.

George, T. V.

1989-01-01

113

Review of the technology for wave power conversion  

Microsoft Academic Search

A review of the technology of useful conversion of wave power is presented. Wave power conversion devices include propulsion schemes, buoy power supply devices, offshore power plants and shore-based power stations. If the power generated from ocean waves is to be competitive, one of the first requirements of a device may be to amplify power density per unit area before

Panicker

1976-01-01

114

Power conditioning system for energy sources  

DOEpatents

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.

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

2008-05-13

115

Economic Factors and Incentives for Ocean Wave Energy Conversion  

Microsoft Academic Search

Ocean energy conversion systems have recently seen renewed interest, stimulated mostly by today's increasing energy discussions. In addition to ocean current energy converters, several commercial ocean wave energy projects have already been undertaken; however, no clear economic model exists for developers to follow. Therefore, this paper focuses on U.S. economic factors that affect the use of wave power for generation

Jennifer G. Vining; Annette Muetze

2009-01-01

116

Energy storage considerations for a stand-alone wave energy plant  

Microsoft Academic Search

Despite several wave energy plants based on oscillating water column concept having been tested worldwide, wave energy has not yet gained popularity as a renewable energy source because of highly intermittent nature of available wave power. Still maintaining a constant voltage and frequency at the output, requires embedding of energy storage devices of sufficient capacity into the system. As the

S. Muthukumar; S. Kakumanu; S. Sriram; V. Jayashankar

2005-01-01

117

Ocean, Wave and Tidal Energy Systems; (USA)  

SciTech Connect

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.

Raridon, M.H.; Hicks, S.C. (eds.)

1991-01-01

118

Average power millimeter wave band travelling wave tube  

Microsoft Academic Search

There is a problem of development of TWTs with operation voltages in units of kV This paper presents the results of research and development of TWT on adjacent resonator chains (ARCs) for 8-mm and 5-mm waves ranges with output power of 5W and 2W, respectively. These TWT have 4-5 kV operation voltages. The 8-mm wave range TWT with much lower

A. P. Kasyanenko; V. E. Kapitonov; I. V. Lopatin

2001-01-01

119

Guidelines in Wave Energy Conversion System Design  

E-print Network

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...

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

2014-01-01

120

California Small Hydropower and Ocean Wave Energy  

E-print Network

California Small Hydropower and Ocean Wave Energy Resources IN SUPPORT OF THE 2005 INTEGRATED....................................................................................................................... 9 Ocean Wave Energy................................................................. 21 #12;ii List of Tables Table 1 California Small Hydropower And Ocean Wave Energy Resources Table 2

121

Second Proof Work, Power, and Energy  

E-print Network

) energy sources, such as solar energy, wind, water flows, ocean and tidal waves, and biomassSecond 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

Kostic, Milivoje M.

122

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

E-print Network

Integration of Wave and Tidal Power into the Haida Gwaii Electrical Grid by Susan Margot Boronowski Committee Integration of Wave and Tidal Power into the Haida Gwaii Electrical Grid by Susan Margot into the potential for electricity generation using both tidal stream and wave energy in Haida Gwaii. A mixed integer

Victoria, University of

123

Sea wave energy conversion  

Microsoft Academic Search

A fixed structure encloses a vertically spaced plurality of superimposed channels that are open at one end of the sea to receive deep sea waves approaching a shoreline. Each of the channels has an entrance ramp that slopes upwardly shorewardly to induce breaking of a wave at and over an apex of the ramp that merges into a shorewardly downwardly

Perkins; C. A. Jr

1978-01-01

124

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

Microsoft Academic Search

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

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

2005-01-01

125

Ocean wave energy conversion concepts  

Microsoft Academic Search

Nine ocean wave energy conversion techniques are described and discussed. These techniques include the use of heaving and pitching bodies, cavity resonators, wave focusing, pressure devices, surging devices, paddles, outriggers and combination devices. Examples of each technique are presented, and required subsystems are described. Finally a comparison study is performed based on efficiency, operational practicality and cost.

M. E. McCormick

1979-01-01

126

Protective, Modular Wave Power Generation System  

SciTech Connect

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.

Vvedensky, Jane M.; Park, Robert Y.

2012-11-27

127

IEEE Power and Energy  

NSDL National Science Digital Library

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

2003-01-01

128

Tunnel effect wave energy detection  

NASA Technical Reports Server (NTRS)

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.

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

1995-01-01

129

A review of impulse turbines for wave energy conversion  

Microsoft Academic Search

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

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

2001-01-01

130

The sea trial of the wave power generator 'Kaimei'  

NASA Astrophysics Data System (ADS)

An experimental Japanese prototype of a wave-power electricity generator system is examined. Construction details and experimental data are presented. The ship-type floating structure, 80 meters in length and 500 tons dead weight, used a non-valve Wells turbine of 0.6 m diameter with four wings, whose energy conversion efficiency was found to be greater than 60% with very small waves, and whose safety factor was found to be greater than that of the impulse turbine. The 'Kaimei' is concluded to be promising, but some technical problems, including increasing and smoothing the output power, remain to be solved.

Masuda, Y.; Miyazaki, T.

1980-10-01

131

The Promise of Wave Power (Invited)  

Microsoft Academic Search

The solutions to today's energy challenges need to be explored through alternative, renewable and clean energy sources to enable diverse energy resource plans. An extremely abundant and promising source of energy exists in the world's oceans: it is estimated that if 0.2 % of the oceans' untapped energy could be harnessed, it could provide power sufficient for the entire world.

T. Brekken

2010-01-01

132

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

E-print Network

for tidal flow of a stratified fluid past a knife edge. The results for the radiated internal wave powerExperimental determination of radiated internal wave power without pressure field data Frank M. Lee to determine, using only velocity field data, the time-averaged energy flux J and total radiated power P

Morrison, Philip J.,

133

Design proposal of electrical system for linear generator wave power plants  

Microsoft Academic Search

This paper describes an electrical system layout for a wave power plant connecting linear generators to the grid. The electrical power out from the wave energy converters must be converted before they can be connected to the grid. The conversion is carried out in marine substations that will be placed on the seabed. The paper presents experimental power data from

C. Bostrom; O. Svensson; M. Rahm; E. Lejerskog; A. Savin; E. Stromstedt; J. Engstrom; H. Gravrakmo; K. Haikonen; R. Waters; D. Bjorklof; T. Johansson; J. Sundberg; M. Leijon

2009-01-01

134

Wave refraction and wave energy on Cayo Arenas  

E-print Network

Area of the breaker zone. b Wave ray spacing. b Deep water wave ray spacing. 0 C Wave phase speed. Cb Wave group speed at breaking. C Wave group speed at end of decay distance. C Deep water wave phase speed. 0 d Water depth. d D Breaking depth... of decay distance. Wave height at down wind end of fetch. H 0 0 Deep water wave height. Deep water unrefracted wave height. i and j Index for summation limits. vi KE Kmetic energy immediately outside breaker zone. b KE. The i th increment...

Walsh, Donald Eugene

1962-01-01

135

Near Shore Wave Modeling and applications to wave energy estimation  

NASA Astrophysics Data System (ADS)

The estimation of the wave energy potential at the European coastline is receiving increased attention the last years as a result of the adaptation of novel policies in the energy market, the concernsfor global warming and the nuclear energy security problems. Within this framework, numerical wave modeling systems keep a primary role in the accurate description of wave climate and microclimate that is a prerequisite for any wave energy assessment study. In the present work two of the most popular wave models are used for the estimation of the wave parameters at the coastline of Cyprus: The latest parallel version of the wave model WAM (ECMWF version), which employs new parameterization of shallow water effects, and the SWAN model, classically used for near shore wave simulations. The results obtained from the wave models near shores are studied by an energy estimation point of view: The wave parameters that mainly affect the energy temporal and spatial distribution, that is the significant wave height and the mean wave period, are statistically analyzed,focusing onpossible different aspects captured by the two models. Moreover, the wave spectrum distribution prevailing in different areas are discussed contributing, in this way, to the wave energy assessmentin the area. This work is a part of two European projects focusing on the estimation of the wave energy distribution around Europe: The MARINA platform (http://www.marina-platform.info/ index.aspx) and the Ewave (http://www.oceanography.ucy.ac.cy/ewave/) projects.

Zodiatis, G.; Galanis, G.; Hayes, D.; Nikolaidis, A.; Kalogeri, C.; Adam, A.; Kallos, G.; Georgiou, G.

2012-04-01

136

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

E-print Network

Energy Storage System Sizing for Smoothing Power Generation of Direct J. Aubry1 , P. Bydlowski 1 E-mail: judicael.aubry Abstract This paper examines the sizing energy storage system (ESS) for energy converter. Keywords: Energy Storage System (ESS), power smoothing, Direct Wave Energy Converter, Supercapacitor, Power

Boyer, Edmond

137

Hydrodynamic Performance of a Wave Energy Converter  

NASA Astrophysics Data System (ADS)

To harvest energy from ocean waves, a new wave energy converter (WEC) was proposed and tested in a wave tank. The WEC freely floats on the water surface and rides waves. It utilizes its wave-driven angular oscillation to convert the mechanical energy of waves into electricity. To gain the maximum possible angular oscillation of the WEC under specified wave conditions, both floatation of the WEC and wave interaction with the WEC play critical roles in a joint fashion. During the experiments, the submersion condition of the WEC and wave condition were varied. The results were analyzed in terms of the oscillation amplitude, stability, auto-orientation capability, and wave frequency dependency.

Yang, Yingchen

2010-11-01

138

On applicability of reciprocating flow turbines developed for wave power to tidal power conversion  

Microsoft Academic Search

Tidal power generation with reciprocating turbines in a simple system is investigated on a performance simulation in order to enlarge the capability of practical use of tidal power with extra-low head and time-varying energy density characteristics. Four reciprocating turbines, which are two types of impulse and a Wells developed for wave power conversion systems, and a cross-flow type of Darrieus

K. Takenouchi; K. Okuma; A. Furukawa; T. Setoguchi

2006-01-01

139

Feasibility assessment of offshore wave and tidal current power production: a collaborative public\\/private partnership  

Microsoft Academic Search

The Electric Power Research Institute (EPRI) and EPRIsolutions are conducting collaborative power production feasibility definition studies on offshore wave energy and tidal current energy on behalf of a number of public and private entities. The outcome of the offshore wave study, which began in 2004, is a compelling techno-economic case for investing in the research, development and demonstration (RD&D) of

O. Siddiqui; R. Bedard

2005-01-01

140

Starting to Experiment with Wave Power  

ERIC Educational Resources Information Center

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…

Hare, Jonathan; McCallie, Ellen

2005-01-01

141

High power millimeter wave ECRH source needs for fusion program  

SciTech Connect

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.

Not Available

1984-06-01

142

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

E-print Network

to on-shore installments, both of which generate power from the oscillating nature of ocean waves. In any case, momentum is transferred from the ocean waves to mechanical power, and in turn, electricity. WECs will also redistribute energy in addition to capturing energy. Power transfer from ocean waves

Haller, Merrick

143

Frequency response analysis of ocean wave energy converter  

Microsoft Academic Search

The energy conversion efficiency and dynamic behavior of a wave energy converter which absorbs power while oscillating on an incident sinusoidal wave train are analyzed. The device consists of two, differently-configured floating bodies connected by a rigid link, and its basic equations are obtained by assuming two-dimensional motions and considering the interaction between the two bodies and hydrodynamic and damping

M. Masubuchi; R. Kawatani

1981-01-01

144

Research and Technology in Wave Energy for Electric Mobility  

E-print Network

efficiency from the wave or tidal power was low. In recent years, developing marine energy converter systemsResearch and Technology in Wave Energy for Electric Mobility Reza Ghorbani Assistant Professor. This was due to both technological and economical challenges in the past. Technically, converting and utilizing

Frandsen, Jannette B.

145

The Dynamics of Wave Energy  

Microsoft Academic Search

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

John Ringwood

146

Direct Drive Wave Energy Buoy  

SciTech Connect

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.

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

2013-07-29

147

A wave focusing device for OWC wave energy convertor  

Microsoft Academic Search

Oscillating Water Column (OWC) device has been widely employed in the wave energy conversion. Wave Focusing Device (WFD) is proposed to improve the operating performance of OWC chamber. In the present paper, a 3D Numerical Wave Tank (NWT) using two-phase VOF model is utilized to simulate the generation and propagation of incident regular waves. The NWT consists of the continuity

Zhen Liu; Beom-Soo Hyun; Jiyuan Jin; Yonghyeon Choi; Hongda Shi; Qin Zhang

2010-01-01

148

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

149

Ultrasound acoustic wave energy transfer and harvesting  

NASA Astrophysics Data System (ADS)

This paper investigates low-power electricity generation from ultrasound acoustic wave energy transfer combined with piezoelectric energy harvesting for wireless applications ranging from medical implants to naval sensor systems. The focus is placed on an underwater system that consists of a pulsating source for spherical wave generation and a harvester connected to an external resistive load for quantifying the electrical power output. An analytical electro-acoustic model is developed to relate the source strength to the electrical power output of the harvester located at a specific distance from the source. The model couples the energy harvester dynamics (piezoelectric device and electrical load) with the source strength through the acoustic-structure interaction at the harvester-fluid interface. Case studies are given for a detailed understanding of the coupled system dynamics under various conditions. Specifically the relationship between the electrical power output and system parameters, such as the distance of the harvester from the source, dimensions of the harvester, level of source strength, and electrical load resistance are explored. Sensitivity of the electrical power output to the excitation frequency in the neighborhood of the harvester's underwater resonance frequency is also reported.

Shahab, Shima; Leadenham, Stephen; Guillot, François; Sabra, Karim; Erturk, Alper

2014-04-01

150

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

E-print Network

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 publications...

Lancaster, Gregor

2011-11-24

151

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

PubMed

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

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

2012-01-28

152

Transverse Flux Permanent Magnet Generator for Ocean Wave Energy Conversion  

Microsoft Academic Search

\\u000a Modern energy demands led the scientific community to renewable energy sources, such as ocean wave energy. The present work\\u000a describes a model for a cost efficient rotary electrical generator, optimized for ocean wave energy conversion. The electrical\\u000a power, supplied by low speed mechanical movement, requires the use of electrical machinery capable of generating high amounts\\u000a of torque. Among the analyzed

José Lima; Anabela Pronto; Mário Ventim Neves

2011-01-01

153

Energy in a String Wave  

NASA Astrophysics Data System (ADS)

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 simple harmonic2. They also know elements of the string at the highest and the lowest positions—the crests and the troughs—are momentarily at rest, while those at the centerline (zero displacement) have the greatest speed, as shown in Fig. 1. Irrespective of this, they are less familiar with the energy associated with the wave. They may fail to answer a question such as, "In a traveling string wave, which elements have respectively the greatest kinetic energy (KE) and the greatest potential energy (PE)?" The answer to the former is not difficult; elements at zero position have the fastest speed and hence their KE, being proportional to the square of speed, is the greatest. To the PE, what immediately comes to their mind may be the simple harmonic motion (SHM), in which the PE is the greatest and the KE is zero at the two turning points. It may thus lead them to think elements at crests or troughs have the greatest PE. Unfortunately, this association is wrong. Thinking that the crests or troughs have the greatest PE is a misconception.3

Ng, Chiu-king

2010-01-01

154

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

155

Wave energy technology in China.  

PubMed

This paper traces the research stages of China's study of wave energy technology, summarizing the findings and deficiencies of each stage from oscillating water column, through onshore oscillating buoy to floating Duck. It also highlights the major innovations in China's new floating Duck device. PMID:22184672

You, Yage; Sheng, Songwei; Wu, Bijun; He, Yunqi

2012-01-28

156

Novel design of an ocean wave power device utilizing a bi-directional turbine  

Microsoft Academic Search

This paper details an innovative design for a wave energy harvester that converts the heaving motion of waves into electrical power. The conceptual design utilizes a unique bi-directional turbine system that develops a torque in a given direction, independent of whether the fluid is moving upward or downward. The result is power production both as the buoy is heaved upward

Steven Helkin; Carlos Velez

2010-01-01

157

Ocean wave energy converting vessel  

SciTech Connect

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.

Boyce, P.F.

1986-08-26

158

Combined power generation with wind and ocean waves  

Microsoft Academic Search

It is often advantageous to generate power with combinations of wind and ocean waves. In fact ocean waves, their generation, propagation, dissipation are directly related to wind velocity and its duration oven the sea. In this paper an attempt has been made to demonstrate statistically to present some advantages with combined wind and ocean wave power generation. Even though many

V. N. M. R. Lakkoju

1996-01-01

159

Optimal switching control of an absorber ocean wave energy device  

Microsoft Academic Search

This paper concerns the preliminary study of a point absorber ocean wave energy converter. A simple floating double-link device oscillates under the wave effect and the power take-off system is a system, which acts like a friction torque. The control consists in locking\\/unlocking the link, which is connected to the power take-off system. The response of the system to the

M. Kamensky; M. Guglielmi; A. Formal'skii

2008-01-01

160

Wave and tide powered generation apparatus  

SciTech Connect

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

Suggs, L. F.

1985-09-03

161

Deployment Effects of Marine Renewable Energy Technologies: Wave Energy Scenarios  

SciTech Connect

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

Mirko Previsic

2010-06-17

162

Catching the right wave: evaluating wave energy resources and potential compatibility with existing marine and coastal uses.  

PubMed

Many hope that ocean waves will be a source for clean, safe, reliable and affordable energy, yet wave energy conversion facilities may affect marine ecosystems through a variety of mechanisms, including competition with other human uses. We developed a decision-support tool to assist siting wave energy facilities, which allows the user to balance the need for profitability of the facilities with the need to minimize conflicts with other ocean uses. Our wave energy model quantifies harvestable wave energy and evaluates the net present value (NPV) of a wave energy facility based on a capital investment analysis. The model has a flexible framework and can be easily applied to wave energy projects at local, regional, and global scales. We applied the model and compatibility analysis on the west coast of Vancouver Island, British Columbia, Canada to provide information for ongoing marine spatial planning, including potential wave energy projects. In particular, we conducted a spatial overlap analysis with a variety of existing uses and ecological characteristics, and a quantitative compatibility analysis with commercial fisheries data. We found that wave power and harvestable wave energy gradually increase offshore as wave conditions intensify. However, areas with high economic potential for wave energy facilities were closer to cable landing points because of the cost of bringing energy ashore and thus in nearshore areas that support a number of different human uses. We show that the maximum combined economic benefit from wave energy and other uses is likely to be realized if wave energy facilities are sited in areas that maximize wave energy NPV and minimize conflict with existing ocean uses. Our tools will help decision-makers explore alternative locations for wave energy facilities by mapping expected wave energy NPV and helping to identify sites that provide maximal returns yet avoid spatial competition with existing ocean uses. PMID:23144824

Kim, Choong-Ki; Toft, Jodie E; Papenfus, Michael; Verutes, Gregory; Guerry, Anne D; Ruckelshaus, Marry H; Arkema, Katie K; Guannel, Gregory; Wood, Spencer A; Bernhardt, Joanna R; Tallis, Heather; Plummer, Mark L; Halpern, Benjamin S; Pinsky, Malin L; Beck, Michael W; Chan, Francis; Chan, Kai M A; Levin, Phil S; Polasky, Stephen

2012-01-01

163

Catching the Right Wave: Evaluating Wave Energy Resources and Potential Compatibility with Existing Marine and Coastal Uses  

PubMed Central

Many hope that ocean waves will be a source for clean, safe, reliable and affordable energy, yet wave energy conversion facilities may affect marine ecosystems through a variety of mechanisms, including competition with other human uses. We developed a decision-support tool to assist siting wave energy facilities, which allows the user to balance the need for profitability of the facilities with the need to minimize conflicts with other ocean uses. Our wave energy model quantifies harvestable wave energy and evaluates the net present value (NPV) of a wave energy facility based on a capital investment analysis. The model has a flexible framework and can be easily applied to wave energy projects at local, regional, and global scales. We applied the model and compatibility analysis on the west coast of Vancouver Island, British Columbia, Canada to provide information for ongoing marine spatial planning, including potential wave energy projects. In particular, we conducted a spatial overlap analysis with a variety of existing uses and ecological characteristics, and a quantitative compatibility analysis with commercial fisheries data. We found that wave power and harvestable wave energy gradually increase offshore as wave conditions intensify. However, areas with high economic potential for wave energy facilities were closer to cable landing points because of the cost of bringing energy ashore and thus in nearshore areas that support a number of different human uses. We show that the maximum combined economic benefit from wave energy and other uses is likely to be realized if wave energy facilities are sited in areas that maximize wave energy NPV and minimize conflict with existing ocean uses. Our tools will help decision-makers explore alternative locations for wave energy facilities by mapping expected wave energy NPV and helping to identify sites that provide maximal returns yet avoid spatial competition with existing ocean uses. PMID:23144824

Kim, Choong-Ki; Toft, Jodie E.; Papenfus, Michael; Verutes, Gregory; Guerry, Anne D.; Ruckelshaus, Marry H.; Arkema, Katie K.; Guannel, Gregory; Wood, Spencer A.; Bernhardt, Joanna R.; Tallis, Heather; Plummer, Mark L.; Halpern, Benjamin S.; Pinsky, Malin L.; Beck, Michael W.; Chan, Francis; Chan, Kai M. A.; Levin, Phil S.; Polasky, Stephen

2012-01-01

164

International Symposium on Wave and Tidal Energy, 2nd, St. John's College, Cambridge, England, September 23-25, 1981, Proceedings  

NASA Astrophysics Data System (ADS)

Topics discussed include wave power device interactions, the mathematical modeling of tidal power, and wave power with air turbines. Particular attention is given to the hydrodynamic characteristics of the Bristol Cylinder, the Strangford Lough tidal energy project, and the Foilpropeller for wave power propulsion. Consideration is also given to a submerged oscillating water column device, models of wave energy transformation near a coast, and the environmental implications of tidal power.

Stephens, H. S.; Stapleton, C. A.

165

Arnold Schwarzenegger DEVELOPING WAVE ENERGY IN  

E-print Network

-Related Environmental Research Neal Fishman Ocean Program Manager Mike Gravely Office Manager Drew Bohan Energy Systems Energy Commission, PIER Energy-Related Environmental Research Program & California Ocean ProtectionArnold Schwarzenegger Governor DEVELOPING WAVE ENERGY IN COASTAL CALIFORNIA: POTENTIAL SOCIO

166

Optimum operation of improved wave-power converter  

Microsoft Academic Search

An improved version of the previously proposed resonance-tuned absorber of ocean-wave power is presented. The absorber utilises a machine to control its movement in an optimum way relative to the time evolvement of the incident wave. As a result, the improved absorber becomes theoretically as efficient in non-harmonic waves as the resonance-tuned absorber is in harmonic waves. Assuming waves and

K. Budal; J. Falnes

1977-01-01

167

Detection of direction and wavelength of ocean wave by power spectrum of ocean wave image  

Microsoft Academic Search

The detection of ocean waves can be used to monitor ocean and to forecast wind-storms upon the ocean surface. The paper presents a method for extracting wave direction and wavelength of ocean waves from a sea image. Based on the assumption that the power spectrum of an ocean wave can be thought of as a thin plane consisting of discrete

Tang Huiming; Xu Shengrong

1992-01-01

168

Energy absorption from ocean waves: a free ride for cetaceans.  

PubMed

Flukes of cetaceans are capable of absorbing energy from ocean waves for propulsion. The extent of this energy absorption is demonstrated by considering the flukes of an immature fin whale, Balaenoptera physalus. In a fully developed seaway corresponding to a wind speed of 20 knots (around Beaufort force 5) and at a low swimming speed, of 2.5 m s-1, this whale was able to absorb up to 25% of its required propulsive power in head seas and 33% of propulsive power in following seas. Consequences of wave-energy absorption for energetics of cetacean migrations are discussed. PMID:1974063

Bose, N; Lien, J

1990-06-22

169

Energy and Momentum Transport in String Waves  

ERIC Educational Resources Information Center

Formulas are derived for the energy, momentum, and angular momentum transmitted by waves of arbitrary shape in an inextensible string by pure transverse waves in a string using Tait's procedure. (Author/CP)

Juenker, D. W.

1976-01-01

170

A performance study on a direct drive hydro turbine for wave energy converter  

Microsoft Academic Search

Clean and renewable energy technologies using ocean energy give us non-polluting alternatives to fossil-fueled power plants\\u000a as a countermeasure against global warming and growing demand for electrical energy. Among the ocean energy resources, wave\\u000a power takes a growing interest because of its enormous amount of potential energy in the world. Therefore, various types of\\u000a wave power systems to capture the

Young-Do Choi; Chang-Goo Kim; You-Taek Kim; Jung-Il Song; Young-Ho Lee

2010-01-01

171

A radioisotope-powered surface acoustic wave transponder  

NASA Astrophysics Data System (ADS)

We demonstrate a 63Ni radioisotope-powered pulse transponder that has a SAW (surface acoustic wave) device as the frequency transmission frequency selector. Because the frequency is determined by a SAW device, narrowband detection with an identical SAW device enables the possibility for a long-distance RF-link. The SAW transponders can be buried deep into structural constructs such as steel and concrete, where changing batteries or harvesting vibration or EM energy is not a reliable option. RF-released power to radioisotope- released power amplification is 108, even when regulatory safe amounts of 63Ni are used. Here we have achieved an 800 µW pulse (315 MHz, 10 µs pause) across a 50 ? load every 3 min, using a 1.5 milli-Ci 63Ni source.

Tin, S.; Lal, A.

2009-09-01

172

Optimisation of wave energy extraction with the Archimedes Wave Swing  

Microsoft Academic Search

This paper addresses the Archimedes Wave Swing (an offshore wave energy converter, which produces electricity from sea waves). It compares the performances of latching control (a discrete, highly non-linear, intrinsically sub-optimum control strategy), of reactive control, of phase and amplitude control (two optimum control strategies that involve non-causal transfer functions, which have to be implemented with approximations, thus rending the

Duarte Valério; Pedro Beirão; José Sá da Costa

2007-01-01

173

On the dynamics of a novel ocean wave energy converter  

NASA Astrophysics Data System (ADS)

Buoy-type ocean wave energy converters are designed to exhibit resonant responses when subject to excitation by ocean waves. A novel excitation scheme is proposed which has the potential to improve the energy harvesting capabilities of these converters. The scheme uses the incident waves to modulate the mass of the device in a manner which amplifies its resonant response. To illustrate the novel excitation scheme, a simple one-degree of freedom model is developed for the wave energy converter. This model has the form of a switched linear system. After the stability regime of this system has been established, the model is then used to show that the excitation scheme improves the power harvesting capabilities by 25-65 percent even when amplitude restrictions are present. It is also demonstrated that the sensitivity of the device's power harvesting capabilities to changes in damping becomes much smaller when the novel excitation scheme is used.

Orazov, B.; O'Reilly, O. M.; Sava?, Ö.

2010-11-01

174

Interacting ocean waves explain powerful seafloor canyon flows  

NASA Astrophysics Data System (ADS)

Off the southwestern coast of Taiwan the Gaoping Submarine Canyon meanders in a giant backward S shape as it stretches southwestward toward the South China Sea. In the canyon, a 200-meter-deep cut into the seafloor that lies 300 meters below the sea's surface, the waters carry an usually large amount of internal tidal power—9.1 megawatts from the canyon's mouth to its head. Along with the strong flows a region of enhanced vertical mixing sits at the canyon's head. Researchers had previously attributed the anomalous flows to internal waves pushing through the Gaoping Canyon, though the source of the energy remained an open question.

Schultz, Colin

2012-02-01

175

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

176

Wave Power Extraction from a Transient Heaving Cylinder  

Microsoft Academic Search

Wave power extracted from the transient motion of a periodically restrained-released heaving circular cylinder proposed by Falnes and Budal is examined under the limitations of linear wave theory excitation. Numerical estimates for the normalized radiated wave amplitudes required for the waveforce excitation derived by Mei are computed from the computationally efficient variational method developed by Black and Mei for the

R. T. Hudspeth; L. S. Slotta

1980-01-01

177

State of the Art of Wave Energy in Spain  

Microsoft Academic Search

Ocean energy is one of the largest renewable resources available on the planet. The term ocean energy includes the surface and subsurface motion of the waves, named wave energy. Spain has a long coast and good wave energy resources that can significantly contribute to the Spanish renewable energy mix. This work presents a description of wave energy and wave energy

J. Fernández Chozas; H. C. Soerensen

2009-01-01

178

Design study of wave power generator for power supply to islands in Far East  

SciTech Connect

Wave power density near Japan is not so high as Europe where Wave power is under development by Joule II project. But multi purpose wave power generator can be designed to generate electricity and promote fishing business near shore. It is improved floating type wave power device. Cylinder Float Backward Bent Duct Buoy (BBDB) is the design. When it is installed in Japanese Island Area such as Izu Seven Islands or South West Islands or Islands in South China Sea including Taiwan. Power cost is estimated about 14 cent/KWh which is economical for Island Power supply.

Masuda, Yoshio [Ryokuseisha Corp., Tokyo (Japan)

1994-12-31

179

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

E-print Network

Farms: Siting, Ocean Area Requirements p7 Offshore Wave Power Resources: Update p9 Shallow Water WaveWave Power Resources off the Hawaiian Islands luisvega@hawaii.edu 1 Wave Resources for Representative Sites Around the Hawaiian Islands Table of Contents Summary p2 Background: Wave Power Conversion p

180

Ocean energy-waves, currents, and tides  

NASA Astrophysics Data System (ADS)

An overview is presented on the mechanical forms of ocean energy; i.e., waves, currents, and tides. Following an introductory section on wave mechanics, each of the three forms of ocean energy is considered under the headings of the resource, device types for energy extraction, and prognosis for practical implementation.

Miles, J.; Shelpuk, B.

1981-05-01

181

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

SciTech Connect

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

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

1997-08-01

182

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

SciTech Connect

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

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

1996-12-31

183

Visualisation of flow conditions inside a shoreline wave power-station  

Microsoft Academic Search

The particle flow inside an oscillating water column type wave power-station varies with time and changes direction. In order to establish flow patterns and energy dissipating mechanisms, and to assess the influence of geometry changes on the hydraulic performance, flow visualisation experiments were conducted on a 1\\/36 two-dimensional model of the Islay prototype wave power-station. It was found that large

Gerald Müller; Trevor J. T. Whittaker

1995-01-01

184

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

NASA Astrophysics Data System (ADS)

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

Black, C.; Haller, M. C.

2013-12-01

185

Wave energy extraction by coupled resonant absorbers.  

PubMed

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

Evans, D V; Porter, R

2012-01-28

186

Wave energy devices with compressible volumes.  

PubMed

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

Kurniawan, Adi; Greaves, Deborah; Chaplin, John

2014-12-01

187

Wave energy devices with compressible volumes  

PubMed Central

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

Kurniawan, Adi; Greaves, Deborah; Chaplin, John

2014-01-01

188

Standing wave tube electro active polymer wave energy converter  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

189

Model study of a shoreline wave-power system  

Microsoft Academic Search

A wave-power system which combines the concept of a breakwater and a harbor resonance chamber was developed in this study. In the caisson chamber, a multi-resonant oscillating water column (MOWC) was formed to push or suck air through the air turbine and thus continuously generated the power. The proposed wave-power system has two aims in mind: one is shore protection

Ruo-Shan Tseng; Rui-Hsiang Wu; Chai-Cheng Huang

2000-01-01

190

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

ERIC Educational Resources Information Center

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…

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

2008-01-01

191

Experimental Testing and Model Validation for Ocean Wave Energy Harvesting Buoys  

E-print Network

Experimental Testing and Model Validation for Ocean Wave Energy Harvesting Buoys Douglas A. Gemme1 are presented for numerical simulations and field experiments using point absorption ocean wave energy for large scale grid power applications, but rather for relatively low-power ocean sensor and communications

Grilli, Stéphan T.

192

The Power of Energy Storage  

E-print Network

The Power of Energy Storage How to Increase Deployment in California to Reduce Greenhouse Gas;1Berkeley Law \\ UCLA Law The Power of Energy Storage: How to Increase Deployment in California to Reduce Greenhouse Gas Emissions Executive Summary: Expanding Energy Storage in California Sunshine and wind, even

Sadoulet, Elisabeth

193

78 FR 40132 - Wave Energy Converter Prize Administration Webinar  

Federal Register 2010, 2011, 2012, 2013, 2014

...Efficiency and Renewable Energy Wave Energy Converter Prize Administration Webinar AGENCY...tentatively titled, ``Wave Energy Converter Prize Administration''. The Office...prize competition related to wave energy converters. The WWPTO anticipates a...

2013-07-03

194

Ocean, Wave, and Tidal Energy Systems: Current abstracts  

NASA Astrophysics Data System (ADS)

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.

Smith, L.; Lane, D. W.

1988-01-01

195

Control system applications in wave energy conversion  

Microsoft Academic Search

Significant improvements in the cost-effectiveness of wave energy devices may be possible with successful implementation of active control of device dynamics. The purpose of this paper is to present an overview of a number of recent applications of active control in wave energy conversion. Simpler frequency domain control applications including reactive control and latching are examined first. Next the difficulties

Umesh A. Korde

2000-01-01

196

Energy 101: Concentrating Solar Power  

ScienceCinema

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.

None

2013-05-29

197

Energy 101: Concentrating Solar Power  

SciTech Connect

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.

None

2010-01-01

198

A grid controlled medium power traveling-wave tube using periodic focusing  

Microsoft Academic Search

The pulse power required by radar systems often imposes a severe load on the pulsing modulator. When traveling-wave or klystron power-output stages are used, the beam is generally pulsed by driving the accelerating electrode to cathode potential. In the past, drive potential and peak energy transfer have been reduced by the use of nonintercepting pulsing electrodes. These methods, however, are

H. J. Wolkstein; G. Novak

1957-01-01

199

The Force of a Tsunami on a Wave Energy Converter  

E-print Network

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.

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

2012-01-01

200

Oblique sounding of the ionosphere by powerful wave beams  

NASA Astrophysics Data System (ADS)

The article is devoted to modeling the impact on the ionosphere powerful obliquely incident wave beam. The basis of this analysis will be orbital variational principle for the intense wave beams-generalization of Fermat's principle to the case of a nonlinear medium (Molotkov and Vakulenko, 1988a,b; Molotkov, 2003, 2005). Under the influence of a powerful wave beam appears manageable the additional stratification of the ionospheric layer F2. Explicit expressions show how the properties of the test beam, with a shifted frequency, released in the same direction as the beam depend on the intensity of a powerful beam and the frequency shift.

Molotkov, I. A.; Atamaniuk, B.

2011-04-01

201

Fundamental research on oscillating water column wave power absorbers  

SciTech Connect

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.

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

1985-03-01

202

PIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY  

E-print Network

PIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY PIEZOELECTRIC POWER SCAVENGING OFPIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGYMECHANICAL VIBRATION ENERGY CE 511- Structural

Ervin, Elizabeth K.

203

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

E-print Network

1 Poster presented at the OCEANS'11 Conference, September, 2011 Seeking Optimal Geometry of a Heaving Body for Improved Wave Power Absorption Efficiency Rachael Hager, Nelson Fernandez and Michelle H generated interest in wave energy. This project has been inspired by Salter's work to better understand wave

204

Optimal control of the magnetohydrodynamic ocean wave energy converter: theory  

Microsoft Academic Search

This paper is a theoretical study of a method to obtain the maximum power output from the magnetohydrodynamic ocean wave energy converter by controlling the applied load impedance. The problem is solved by using the Pontriagin's maximum principle. The solution, obtained by finding the stationary point of the Hamiltonian function, turns out to be the linearizing feedback, This makes it

Dmitry A. Altshuller; Robert A. Koslover

2005-01-01

205

Preliminary analysis of wave energy conversion at an offshore structure  

Microsoft Academic Search

A study of the feasibility of utilizing wave energy to provide the electrical power to operate the Buzzards Bay Light Tower has been carried out. It was concluded that a pneumatic buoy attached to the light tower would be the best solution. Experiments were conducted in the MIT Towing Tank to estimate the performance of such a device. The loads

A. D. Carmichael; D. Assanis; J. O. Salsich

1982-01-01

206

Performance optimization of a pneumatic wave energy conversion device  

Microsoft Academic Search

The purpose of this study was, for the first time, to optimize the performance of a pneumatic wave energy conversion device. The experiments of Jolly and Newmaster (1979) and Trop and Casey (1980) left a capture chamber and turbine for further investigation. To optimize the system performance the turbine had to be first analyzed so that its power performance curves

S. W. Surko

1982-01-01

207

A methodology for production and cost assessment of a farm of wave energy converters  

Microsoft Academic Search

To generate a substantial amount of power, Wave Energy Converters (WECs) are arranged in several rows or in a ‘farm’. Both the power production and cost of a farm are lay-out dependent.In this paper, the wave power redistribution in and around three farm lay-outs in a near shore North Sea wave climate, is assessed numerically using a time-dependent mild-slope equation

Charlotte Beels; Peter Troch; Jens Peter Kofoed; Peter Frigaard; Jon Vindahl Kringelum; Peter Carsten Kromann; Martin Heyman Donovan; Julien De Rouck; Griet De Backer

2011-01-01

208

Understanding Wave Motion and Power Loss  

NSDL National Science Digital Library

This lab, presented by the National Nanotechnology Infrastructure Network, covers the concept of wave properties. Students will learn how light waves interact with matter. The activity is "analogous to light traveling through optical media having different indices of refraction (densities)." Teacher Preparation Guides, Student Guides, and Next Generation Science Standards applicable to the lesson are included.

209

Simulation of coastal wave spectra energy from ENVISAT satellite data  

NASA Astrophysics Data System (ADS)

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.

Marghany, Maged

2014-06-01

210

Stochastic Control of Inertial Sea Wave Energy Converter  

PubMed Central

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.

Mattiazzo, Giuliana; Giorcelli, Ermanno

2015-01-01

211

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

SciTech Connect

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.

Gary, N E; Westerdahl, B B

1980-12-01

212

Process and apparatus for generating electrical power from ocean waves  

Microsoft Academic Search

An apparatus is described for generating electrical power from ocean waves comprising: first housing means adapted for submersion at a selected depth beneath the ocean waves, the first housing means including at least on opening therethrough; first flexible bladder means, the first bladder means being disposed within the first housing means; electrical generating means being associated with the first housing

Meyerand

1986-01-01

213

Shock wave shape on power law leading edges  

Microsoft Academic Search

Computations using the Direct Simulation Monte Carlo method are presented for hypersonic flow on power law shaped leading edges. The primary aim of this paper is to examine the geometry effect of such leading edges on the shock wave structure. The sensitivity of the shock wave shape and shock standoff distance to shape variations of such leading edges is calculated

W. F. N. Santos

2005-01-01

214

An Experimental High Power Pulsed Travelling Wave Tube†  

Microsoft Academic Search

This paper describes an experimental travelling wave tube with a saturated efficiency of 34%, a power output of 3 megawatts and a gain of 35 dB.An essential feature of this tube was a high impedance slow wave structure, with good thermal dissipation and suitable for use with a high voltage (100 kv) electron beam. The high voltage, which was needed

J. F. GITTINS; N. H. ROCK; A. B. J. SULLIVAN

1957-01-01

215

Wave Energy Resource Analysis for Use in Wave Energy Conversion  

E-print Network

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

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

2014-01-01

216

The electromagnetic spectrum : waves of energy  

NSDL National Science Digital Library

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

Tracy Coulson

2002-01-01

217

A resonant point absorber of ocean-wave power  

Microsoft Academic Search

A system for absorbing and utilizing the energy carried by ocean waves is discussed. The 'point absorber' considered is a system in which the horizontal extent is much smaller than one wavelength. The point absorber is optimized for efficient energy conversion. The resonant characteristic frequency of the system is at all times tuned to the characteristic frequency of the wave.

K. Budar; J. Falnes

1975-01-01

218

Counting energy packets in the electromagnetic wave  

E-print Network

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

Stefan Popescu; Bernhard Rothenstein

2007-05-18

219

Self-similar relativistic blast waves with energy injection  

NASA Astrophysics Data System (ADS)

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.

van Eerten, Hendrik

2014-08-01

220

Millimeter wave Space Power Grid architecture 2011  

Microsoft Academic Search

The Space Power Grid architecture jump-starts the move towards Space Solar Power (SSP) by setting up a power exchange between terrestrial power plants and customers through Space. A constellation of low-mass, low-risk waveguide satellites starts the first phase. With technical and policy issues settled and the market risk reduced, expansion to full SSP is done using high-altitude ultralight sunlight reflector

Narayanan Komerath; Brendan Dessanti; Shaan Shah; Richard Zappulla; Nicholas Picon

2012-01-01

221

An Energy Recovering Divertor Based on Amplification of Alfven Waves  

NASA Astrophysics Data System (ADS)

A new technique for direct power extraction from a fusion plasma is presented. This technique is designed to operate within a tokamak divertor channel without requiring plasma to cross the toroidal field coils, and is therefore termed an energy recovering divertor. The proposed technique is based on amplification of Alfven waves by ion kinetic energy, using a mechanism analogous to a free-electron laser. Presented here are a detailed description of the technique and analytic calculations of its basic mode of operation.

Baver, D. A.

2013-04-01

222

Multistable chain for ocean wave vibration energy harvesting  

NASA Astrophysics Data System (ADS)

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.

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

2014-03-01

223

ENERGY EFFICIENCY RESEARCH POWERS  

E-print Network

Californiaratepayers,theEnergy Commissionimplementedthecountry'sfirstenergyeffi- ciencybuildingandappliancestandardsin1978.Theregu- lationsinCalifornia'sAppliance incorporated into the building and appliance stan- dards. This included research on television energy use, externalpowersupplies,batterychargers,residentialfur- nacefans,coolroofsforhomes,homeatticducts,kitchen

224

Direct Drive Wave Energy Buoy – 33rd scale experiment  

SciTech Connect

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.

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

2013-07-29

225

Status and potentials of offshore wave energy resources in Chahbahar area (NW Omman Sea)  

Microsoft Academic Search

Chahbahar area is located at the southern coasts of Iran in the Omman Sea. This paper examines possible examples of offshore wave power installations at Chahbahar area in the Omman Sea. The study aims at showing the physical possibilities of wave energy and electric power generation based upon point-absorbers and attenuator devices in the selected site. This site has been

Ali Rashid; Smaeyl Hasanzadeh

2011-01-01

226

A survey of technologies used in wave energy conversion systems  

Microsoft Academic Search

Now-a-days, the energy extraction and conversion from the ocean waves has attracted large attention. A number of wave energy conversion systems have been proposed to convert the mechanical energy of the ocean wave into electrical energy. This paper presents a review of the status of wave energy conversion (WEC) technology and discusses the different types of devices used in present

Khalid. H. Mohamed; N. C. Sahoo; Taib B. Ibrahim

2011-01-01

227

Pulse shortening in a high power backward wave oscillator  

Microsoft Academic Search

Summary form only given. 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

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

1996-01-01

228

Near-Millimeter Wave Issues for a Space Power Grid  

Microsoft Academic Search

This paper reports continuing work on an evolutionary revenue-generating approach to Space Solar Power. The 220 GHz atmospheric transmission window is chosen, leaving open the option of using millimeter wave or laser wavelengths. The progression from frequency to system business case is laid out, seeking the performance figures needed for a self-sustaining system and to open up Space Solar Power

Narayanan Komerath; Vigneshwar Venkat; Jason Fernandez

2009-01-01

229

Ocean Wave Energy Conversion - A Survey  

Microsoft Academic Search

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

A. Muetze; J. G. Vining

2006-01-01

230

A new power meter concept for high energy lasers  

Microsoft Academic Search

We describe a new concept for measurement of High Energy Laser (HEL) power. The technique is based upon the phenomenon of optoacoustic detection, which is a sensitive measurement of the sound waves created by absorption of a laser beam of known power with a sample of absorber material for the purpose of absorption coefficient determination. We propose that this process

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

1981-01-01

231

New power meter concept for high energy lasers. Memorandum report  

Microsoft Academic Search

We describe a new concept for measurement of High Energy Laser (HEL) power. The technique is based upon the phenomenon of optoacoustic detection, which is a sensitive measurement of the sound waves created by absorption of a laser beam of known power with a sample of absorber material for the purpose of absorption coefficient determination. We propose that his process

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

1981-01-01

232

24 DTU International Energy Report 2013 Stochastic power generation  

E-print Network

that their power output can be curtailed if necessary. Renewable energy sources such as wind, solar, wave and tidal power are characterised as variable and of limited predictability. They are formally known as stochastic generation, though some may be technology-specific. In this chapter the main emphasis is on the daily

Paris-Sud XI, Université de

233

Water Power for a Clean Energy Future (Fact Sheet)  

SciTech Connect

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.

Not Available

2010-07-01

234

The Power of Energy  

NSDL National Science Digital Library

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

Diana Congden

2012-06-14

235

Model Experiments On Waves And Nearshore Currents Around Floating Wave Power Plant In Coastal Waters In Comparison With Detached Breakwater  

Microsoft Academic Search

This paper deals with i) the roles of floating wave power plant in the control of environment of coastal waters for coastal fisheries, i i) experimental investigation of physical characteristics,i.e. waves and nearshore currents induced by waves around a model of floating wave power plant on inclined bottom comparing with those around a model of detached breakwater from the viewpoints

Naomi Kato; Takeaki Miyazaki

1991-01-01

236

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

ERIC Educational Resources Information Center

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…

Harris, Fank

2014-01-01

237

Renewable Energy Powers Renewable Energy Lab, Employees  

E-print Network

. NREL is also using solar energy for auxiliary purposes such as powering streetlights, water pumps and the lab's new entrance sign. An experimental 12-kilowatt rooftop solar system also feeds electricity back

238

Energy 101: Concentrating Solar Power  

NSDL National Science Digital Library

This video describes how concentrating solar power (CSP) technologies reflect and collect solar energy to generate electricity. This video explains what CSP is, how it works, and focuses on parabolic troughs.

National Renewable Energy Laboratory (NREL)

239

Development of Sub-Millimeter-Wave Power Amplifiers  

NASA Astrophysics Data System (ADS)

In this paper, we present the framework for developing the first working power amplifiers at sub-millimeter-wave frequencies. The technology is made possible by an advanced InP HEMT transistor. A three-stage power amplifier is presented, which uses a binary combiner to realize a total output periphery of 80 mum and demonstrates 12-dB gain at 335 GHz, making, this the first demonstrated sub-millimeter-wave power amplifier. Measured saturated power of 2 mW at 330 GHz is also presented, which provides a transistor power benchmark of 25 mW/mm at 330 GHz. Finally, single-stage amplifier data with large periphery transistors are presented, which demonstrates 5-dB measured gain at 230 GHz and positive measured S21 gain to ~300 GHz, demonstrating that power amplifiers using larger transistors are feasible at these frequencies as well.

Deal, William R.; Mei, X. B.; Radisic, Vesna; Lange, Michael D.; Yoshida, Wayne; Liu, Po-Hsin; Uyeda, Jansen; Barsky, Michael E.; Fung, Andy; Gaier, Todd; Lai, Richard

2007-12-01

240

Energy, A Crisis in Power.  

ERIC Educational Resources Information Center

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…

Holdren, John; Herrera, Philip

241

Heterostructure Varactor Diodes for Microwave and Millimetre Wave Power Generation  

Microsoft Academic Search

\\u000a Multipliers are frequently used for generating millimeter and submillimeter wave power. The varactor multiplier uses a non-linear\\u000a capacitance diode to transform power at a frequency fp to power at n·fp [1]. A general problem is that in order to have devices with reasonable impedance properties, they must be made smaller the\\u000a higher the frequency, which immediately leads to lower output

E. L. Kollberg

242

Modeling of an ocean waves power device AWS  

Microsoft Academic Search

This paper describes the steps for building the time domain model of an ocean waves energy converter device called AWS (Archimedes wave swing). This model is useful for the design of such devices and for the prediction of its behavior in different sea conditions. Besides the inherent complexity associated to the nonlinear dynamics of the AWS components, for time domain

Jod Si da Costa; Pedro Pinto; Anthio Sarmento; Fred Gardner

2003-01-01

243

The Development of a Rotational Wave Energy Conversion System: Design and Simulations  

Microsoft Academic Search

Electrical power generation by means of renewable energies is becoming a flourishing industry with many researchers focusing on investigating new and effective ways to harness this power. This paper presents a new proposed mechanism for harnessing the potential energy of open ocean waves and the procedures of efficiently converting this energy into electricity. Unlike many of the already proposed designs

H. Bora Karayaka; Hugo Mahlke; Mehrube Mehrubeoglu

2011-01-01

244

Analysis of the power capacity of overmoded slow wave structures  

NASA Astrophysics Data System (ADS)

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 TM0n modes in overmoded SWSs are numerically investigated. Our analysis reveals the following facts. First, the power capacity of higher order TM0n modes is apparently larger than that of TM01 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 TM01 mode in overmoded SWSs grows with diameter does not slow down as the TM01 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 TM01 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 TM0n modes in overmoded SWSs if we want to improve the power capacity of overmoded O-type Cerenkov HPM generators working at high frequency.

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

2013-07-01

245

Analysis of the power capacity of overmoded slow wave structures  

SciTech Connect

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.

Zhang, Dian; Zhang, Jun; Zhong, Huihuang; Jin, Zhenxing [College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha 410073 (China)] [College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

2013-07-15

246

Wave energy in Europe: current status and perspectives  

Microsoft Academic Search

The progress in wave energy conversion in Europe during the past ten years is reviewed and current activities and initiatives in the wave energy sector at National and Union level are described. Other important activities worldwide are summarized. The technical and economical status in wave energy conversion is outlined and important wave energy developments are presented.

Alain Clément; Pat McCullen; António Falcão; Antonio Fiorentino; Fred Gardner; Karin Hammarlund; George Lemonis; Tony Lewis; Kim Nielsen; Simona Petroncini; M.-Teresa Pontes; Phillippe Schild; Bengt-Olov Sjöström; Hans Christian Sørensen; Tom Thorpe

2002-01-01

247

The assessment of ocean wave energy along the coasts of Taiwan  

NASA Astrophysics Data System (ADS)

The wave energy resource around the coasts of Taiwan is investigated with wave buoy data covering a 3-year period (2007-2009). Eleven study sites within the region bounded by the 21.5°N-25.5°N latitudes and 118°E-122°E longitudes are selected for analysis. The monthly moving-average filter is used to obtain the low-frequency trend based on the available hourly data. After quantifying the wave power and annual wave energy, the substantial resource is the result of Penghu buoy station, which is at the northeastern side of Penghu Island in the Taiwan Strait. It is investigated that the Penghu sea area is determined to be the optimal place for wave energy production according to its abundant resource of northeasterly monsoon waves, sheltering of the Taiwan Island, operation and maintenance in terms of seasonal conditions, and constructability of wave power devices.

Lin, Yu-Hsien; Fang, Ming-Chung

2012-09-01

248

Wave energy conversion with an oscillating water column on a fixed offshore platform  

Microsoft Academic Search

The purpose of this study is to examine the feasibility of practical wave energy conversion using an oscillating water column (OWC) and a counter-rotating turbine on a fixed offshore platform. A linear array of such platforms along a coastline, with the power transmitted ashore by submarine cable, constitutes the type of wave energy powerplant discussed herein. The OWC concept utilizes

W. L. Green; J. J. Campo; J. B. Miles; J. A. Miller; J. E. Parker

1983-01-01

249

Experimental and Numerical Study of Spar Buoy-magnet/spring Oscillators Used as Wave Energy Annette R. Grilli  

E-print Network

within a coil. This system is aimed at producing low and renewable wave power (up to ¢ £ ¤ ¥ k.g., latching) of the SSLG, in order to further improve power generation. KEYWORDS : Wave energy systems of independent oscillators, point absorbers (Stallard et al, 2005). [A review of various forms of ocean wave

Grilli, Stéphan T.

250

An Experimental C.W. Power Travelling-wave Tube†  

Microsoft Academic Search

This paper describes an experimental C.W. travelling-wave tube with a power output of the order of a kilowatt at X-band and a gain of up to 22 dB. At fixed beam voltage the bandwidth is about 1.5 %, By varying the beam voltage the tube can be operated over a 6 % range of frequencies.The slow wave structure is of

M. O. BRYANT; J. F. GITTINS; F. WRAY

1959-01-01

251

Power and polarization monitor development for high power millimeter-wave  

SciTech Connect

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.

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

2014-11-15

252

Limitations on millimeter-wave power generation with spiraling electron beams.  

NASA Technical Reports Server (NTRS)

A study is made of the suitability of the interaction between a thin, solid, spiraling electron beam of 5-15-kV energy and a microwave cavity, for the purpose of generating watts of CW millimeter-wave power. The effect of finite energy spread in the electron beam is considered both theoretically and experimentally. Measured results are given for a prototype device operating at 9.4 GHz. Power outputs of 5 W and electronic efficiencies near 2% have been obtained. The data agree well with the theory, subject to some ambiguity in the energy-distribution parameters. The performance is strongly limited by the energy spread in the beam.

Kulke, B.

1972-01-01

253

Millimetre wave gyrotron operation at high efficiency and power levels  

NASA Astrophysics Data System (ADS)

Gyrotrons have reached impressive levels of performance such as pulse power output of a megawatt at frequencies higher than 100 GHz. Their applications include plasma heating for controlled fusion, high precision radar, RF source for accelerators, and ceramic heating. Operation in fundamental mode at millimeter wave frequencies requires the use of superconducting magnets. Harmonic operation offers the advantage of a lowered requirement of magnetic field intensity though at a lowered RF efficiency. Large-orbit gyrotrons are particularly suited for high harmonic operation. Techniques for enhancement of efficiency by energy recovery from spent beams are delineated for large as well as small-orbit gyrotrons. Achievement of high power levels in small-orbit gyrotrons is discussed along with related issues of complex cavities as well as cavities operating in 'whispering gallery' modes, and their mode stability. Quasi-optical gyrotrons have reduced mode density. However, mode competition still exists from longitudinal modes. Current research on single mode stability is outlined with reference to beam parameters.

Singh, Amarjit

1990-12-01

254

Solar energy power generation system  

SciTech Connect

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

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

1986-05-06

255

Practical Challenges in Harvesting Wave Energy  

Microsoft Academic Search

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

John Ringwood

256

CHARACTERIZING DANGEROUS WAVES FOR OCEAN WAVE ENERGY CONVERTER SURVIVABILITY Justin Hovland  

E-print Network

CHARACTERIZING DANGEROUS WAVES FOR OCEAN WAVE ENERGY CONVERTER SURVIVABILITY Justin Hovland ABSTRACT Ocean Wave Energy Converters (OWECs) operating on the water surface are subject to storms gradient technologies. This paper is focused on Ocean Wave Energy Converters (OWECs) and the need

Haller, Merrick

257

Investigation of suitable sites for Wave Energy Converters around Sicily (Italy)  

NASA Astrophysics Data System (ADS)

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 hot-spot-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 may be possible sites for the implementation of WEC farms.

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

2015-02-01

258

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

E-print Network

Wave Energy Ecological Effects Workshop page 1 of 4 Ecological Effects of Wave Energy Development) develop an initial assessment of the potential impacting agents and ecological effects of wave energy are currently unknown. Benthic Habitat · Wave energy development can have a large

Wright, Dawn Jeannine

259

Wave-actuated power take-off device for electricity generation  

SciTech Connect

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?

Chertok, Allan

2013-01-31

260

On scattering of a gas behind deflagration waves propelled by powerful radiation fluxes  

Microsoft Academic Search

Two self-similar problems about plane nonstationary gas scattering in a vacuum behind a deflagration wave for which the conservation laws are satisfied are considered. The energy flux density is considered to vary according to a power law. In the first problem the gas is transparent and scattered adiabatically. The solution is found analytically. It is shown that the Jouguet condition

I. V. Nemchinov

1973-01-01

261

Reserve requirement impacts of large-scale integration of wind, solar, and ocean wave power generation  

Microsoft Academic Search

Many sources of renewable energy, including solar, wind, and ocean wave, offer significant advantages such as no fuel costs and no emissions from generation. However, in most cases these renewable power sources are variable and non-dispatchable. The utility grid is already able to accommodate the variability of the load and some additional variability introduced by sources such as wind. However,

D. A. Halamay; T. K. A. Brekken; A. Simmons; S. McArthur

2010-01-01

262

Reserve Requirement Impacts of Large-Scale Integration of Wind, Solar, and Ocean Wave Power Generation  

Microsoft Academic Search

Many sources of renewable energy, including solar, wind, and ocean wave, offer significant advantages such as no fuel costs and no emissions from generation. However, in most cases these renewable power sources are variable and nondispatchable. The utility grid is already able to accommodate the variability of the load and some additional variability introduced by sources such as wind. However,

Douglas A. Halamay; Ted K. A. Brekken; Asher Simmons; Shaun McArthur

2011-01-01

263

Large-scale integration of optimal combinations of PV, wind and wave power into the electricity supply  

Microsoft Academic Search

This article presents the results of analyses of large-scale integration of wind power, photo voltaic (PV) and wave power into a Danish reference energy system. The possibility of integrating Renewable Energy Sources (RES) into the electricity supply is expressed in terms of the ability to avoid excess electricity production. The different sources are analysed in the range of an electricity

H. Lund

2006-01-01

264

Experimental demonstration of a high-power slow wave electron cyclotron maser utilizing corrugated metal structure  

SciTech Connect

High-power microwave (HPM) sources based on electron cyclotron resonance (ECR) such as gyrotrons are fast wave devices and velocity component of electron beam perpendicular to guiding magnetic field is the origin of HPM. HPM sources based on Cherenkove mechanism are slow wave devices and can be driven by a beam without initial perpendicular velocity. The authors present here the experimental result that seems to be the first demonstration of high-power slow wave electron cyclotron maser (ECM) consisting of a large diameter sinusoidally corrugated metal waveguide driven by a beam with predominant parallel velocity. The designed size parameters of slow wave structure (SWS) are as follows: average radius 30 mm, corrugation pitch 3.4 mm, its amplitude h = 1.7 mm and total length 238 mm. They use an annular beam with radius 26.3 mm, energy 55 keV, current 200 A in their experiment. Expected Cherenkov oscillation frequency of TM01 mode is 20 GHz. The observed high-power microwaves can be quantitatively explained by a backward wave oscillation with Cherenkov mechanism enhanced by positive feedback of anomalous Doppler slow cyclotron wave. In conclusion, the slow wave ECM presented here will be a competitive candidate against gyrotrons for generating multi-MW millimeter microwaves available in fusion plasma research.

Minami, K.; Ogura, K.; Kurashina, K; Kim, W. [Niigata Univ. (Japan). Dept. of Electrical Engineering; Watanabe, Tsuguhiro [National Inst. for Fusion Research, Nagoya (Japan); Carmel, Y.; Destler, W.W.; Granatstein, V.L. [Univ. of Maryland, College Park, MD (United States). Inst. for Plasma Research

1994-12-31

265

Coaxial extraction of RF power from a traveling wave amplifier  

SciTech Connect

The authors present new results from a high-power relativistic traveling wave tube amplifier experiment in which the RF power is extracted in a coaxial output section. The amplifier consists of two slow-wave structures separated by a resistive sever. The first stage imparts a small modulation to the beam. The second stage consists of an iris-loaded circular waveguide which is tapered from both ends by an adiabatic increase in the iris aperture with each successive period. The periodic length and the external cavity radius are kept constant. This provides a low-reflection transition from the slow-wave structure to the empty circular waveguide. A coaxial inner conductor is inserted into the output tapered section of the slow-wave structure and its` position and radius chosen to minimize reflections and maximize extracted RF power. It is shown both experimentally and through MAGIC simulations that a fairly low reflection circular TM{sub 01} to coaxial TEM mode transition can be made this way. Any small reflections form the output end travel backwards and are absorbed in the sever. In contrast to the traditional transverse extraction of power into a rectangular waveguide, the coaxial extraction is fairly broadband and exhibits much lower sensitivity to dimensions. The beam is dumped through an aperture in the inner conductor. Presently, the power is extracted into the coaxial waveguide and absorbed into a tapered resistive load. This will be later converted to the TE{sub 10} mode of a rectangular waveguide.

Naqvi, S.; Kerslick, G.S.; Nation, J.A.; Schaecter, L. [Cornell Univ., Ithaca, NY (United States)

1996-12-31

266

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

E-print Network

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 ...

Spaulding, Jonathon David

2010-01-01

267

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

E-print Network

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 ...

Crozier, Richard Carson

2014-06-30

268

The Future Potential of Wave Power in the US  

NASA Astrophysics Data System (ADS)

The theoretical ocean wave energy resource potential exceeds 50% of the annual domestic energy demand of the US, is located in close proximity of coastal population centers, and, although variable in nature, may be more consistent and predictable than some other renewable generation technologies. As renewable electricity generation technologies, ocean wave energy offers a low air pollutant option for diversifying the US electricity generation portfolio. Furthermore, the output characteristics of these technologies may complement other renewable technologies. This study addresses: (1) The energy extraction potential from the US wave energy resource, (2) The present cost of wave technology in /kW, (3) The estimated cost of energy in /kWh, and (4) Cost levels at which the technology should see significant deployment. RE Vision Consulting in collaboration with NREL engaged in various analyses to establish present-day and future cost profiles for MHK technologies, compiled existing resource assessments and wave energy supply curves, and developed cost and deployment scenarios using the ReEDS analysis model to estimate the present-day technology cost reductions necessary to facilitate significant technology deployment in the US.

Previsic, M.; Epler, J.; Hand, M.; Heimiller, D.; Short, W.; Eurek, K.

2012-12-01

269

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

DOEpatents

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.

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

1999-01-01

270

Electromagnetic wave energy conversion research  

NASA Technical Reports Server (NTRS)

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.

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

1975-01-01

271

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

NASA Astrophysics Data System (ADS)

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.

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

2015-02-01

272

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

PubMed Central

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

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

2015-01-01

273

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

PubMed

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

Wong, Alex M H; Eleftheriades, George V

2015-01-01

274

Wave Energy Resources Representative Sites Around the Hawaiian Islands  

E-print Network

and Barriers p4 Wave Power Resources: Previous Work p5 Wave Farms: Siting, Ocean Area Requirements p7 OffshoreW/m)=f(Hs;Te;) Proprietary kWh Ocean Area not 24/7 Transfer Function #12;Wave Power Resources off the Hawaiian Islands. Vega Ph.D October 11, 2010 #12;Wave Power Resources off the Hawaiian Islands October 11, 2010 1

275

Analysis of dynamic effects relevant for the wear damage in hydraulic machines for wave energy conversion  

Microsoft Academic Search

The present paper deals with a mathematical model of a heaving-buoy Wave Energy Converter (WEC) equipped with high-pressure hydraulic power take-off machinery for energy conversion. This model is based on linear hydrodynamic theory, and a hybrid frequency–time domain model is used to study the dynamics of the heaving-body exposed to an irregular incident wave. For the power take-off system, end-stop

Limin Yang; Jørgen Hals; Torgeir Moan

2010-01-01

276

PBS Learning Media: Origins of Wave Energy  

NSDL National Science Digital Library

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

277

Phase velocity and interaction impedance on slow-wave structures for power traveling-wave tubes  

Microsoft Academic Search

In this work, some results from a theoretical cold analysis of the ring-bar slow-wave structure are shown. The ring-bar structure is suitable to be used in high-power traveling-wave tubes. Thus, an investigation was done in order to understand the properties of this structure and why it is better than single helices when a TWT is operated at high-voltage levels. The

Daniel T. Lopes; Cláudio C. Motta

2008-01-01

278

Chromospheric alfvenic waves strong enough to power the solar wind.  

PubMed

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

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

2007-12-01

279

Efficiency enhancement in high power backward-wave oscillators  

Microsoft Academic Search

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 BWOs. One of the major contributors to the high efficiency of the plasma-filled Pasotron

Dan M. Goebel; E. A. Adler; Elmira S. Ponti; J. R. Feicht; Robert L. Eisenhart; Raymond W. Lemke

1999-01-01

280

Measurement Of Telephone Noise and Power Wave Shape  

Microsoft Academic Search

Since the original introduction of devices for measuring or rating the wave shape of power system currents and voltages in terms of their influence on exposed telephone circuits, much additional work on this problem has been done, the results of this work are reported in this paper. In part I, a curve of relative interfering effects based upon recent studies

J. M. Barstow; P. W. Blye; H. E. Kent

1935-01-01

281

Water Power for a Clean Energy Future (Fact Sheet)  

SciTech Connect

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.

Not Available

2012-03-01

282

Energy Industry Powers CTE Program  

ERIC Educational Resources Information Center

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…

Khokhar, Amy

2012-01-01

283

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

NASA Astrophysics Data System (ADS)

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

Walker, A. D. M.

2014-12-01

284

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

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

285

High Energy Physics and Gravitational Waves  

NASA Astrophysics Data System (ADS)

I discuss the possible relevance of gravitational-wave (GW) experiments for high energy physics. I examine three topics: the relic GW background, the GW bursts form instabilities in neutron stars, the GW signal from a supernova. The basic principles and the physics cases are reported.

Coccia, Eugenio

2014-06-01

286

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

SciTech Connect

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 .

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

2014-09-01

287

Purely Nonlinear Instability of Standing Waves with Minimal Energy  

E-print Network

Purely Nonlinear Instability of Standing Waves with Minimal Energy the standing wave that has the minimal energy among all other standing waves is unstable, in spite, dubbed as standing waves: u(t,* * x) = e-i!tOE!(x), where ! is from a certain interval R

Comech, Andrew

288

Application of fluid–structure interaction simulation of an ocean wave energy extraction device  

Microsoft Academic Search

A numerical technique that employs a computational fluid dynamics (CFD) code is used to perform coupled fluid–structure interaction simulation of a wave energy device in order to assess power output in a 3D numerical wave flume. The current method determines the motion of the buoy from the dynamic solution of the fluid flow problem and the dynamic buoy motion problem

Emmanuel B. Agamloh; Alan K. Wallace; Annette von Jouanne

2008-01-01

289

Floating type ocean wave power station equipped with hydroelectric unit  

NASA Astrophysics Data System (ADS)

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.

Okamoto, Shun; Kanemoto, Toshiaki; Umekage, Toshihiko

2013-10-01

290

Analysis of the impacts of Wave Energy Converter arrays on the nearshore wave climate in the Pacific Northwest  

NASA Astrophysics Data System (ADS)

As concerns over the use of fossil fuels increase, more and more effort is being put into the search for renewable and reliable sources of energy. Developments in ocean technologies have made the extraction of wave energy a promising alternative. Commercial exploitation of wave energy would require the deployment of arrays of Wave Energy Converters (WECs) that include several to hundreds of individual devices. Interactions between WECs and ocean waves result in both near-field and far-field changes in the incident wave field, including a significant decrease in wave height and a redirection of waves in the lee of the array, referred to as the wave shadow. Nearshore wave height and direction are directly related to the wave radiation stresses that drive longshore currents, rip currents and nearshore sediment transport, which suggests that significant far-field changes in the wave field due to WEC arrays could have an impact on littoral processes. The goal of this study is to investigate the changes in nearshore wave conditions and radiation stress forcing as a result of an offshore array of point-absorber type WECs using a nested SWAN model, and to determine how array size, configuration, spacing and distance from shore influence these changes. The two sites of interest are the Northwest National Marine Renewable Energy Center (NNMREC) test sites off the coast of Newport Oregon, the North Energy Test Site (NETS) and the South Energy Test Site (SETS). NETS and SETS are permitted wave energy test sites located approximately 4 km and 10 km offshore, respectively. Twenty array configurations are simulated, including 5, 10, 25, 50 and 100 devices in two and three staggered rows in both closely spaced (three times the WEC diameter) and widely spaced (ten times the WEC diameter) arrays. Daily offshore wave spectra are obtained from a regional WAVEWATCH III hindcast for 2011, which are then propagated across the continental shelf using SWAN. Arrays are represented in SWAN through the external modification of the wave spectra at the device locations, based on a new experimentally determined Power Transfer Function established in an earlier WEC-array laboratory study. Changes in nearshore forcing conditions for each array size and configuration are compared in order to determine the scale of the far-field effects of WEC arrays and which array sizes and configurations could have the most significant impacts on coastal processes.

O'Dea, A.; Haller, M. C.

2013-12-01

291

Comparison of methods for computing hydrodynamic characteristics of arrays of wave power devices  

Microsoft Academic Search

A comparison of methods for the calculation of the hydrodynamic characteristics of arrays of wave power devices is presented. In particular, the plane-wave approximation and an exact multiple scattering formulation have been used to compute exciting wave forces, hydrodynamic coefficients and q factors for arrays of interacting wave power devices. The results obtained are compared with each other, and accuracy

S. A. Mavrakos; P. McIver

1997-01-01

292

The design of a palette-type wave energy converter system supported by Buoys  

Microsoft Academic Search

The oceans and seas contain a vast quantity of mechanical energy in form of surface waves and tides. The high density of oscillating water results in high energy densities, making it a favorable form of hydro power. The estimated sea wave energy potential in the world is about 1kW\\/m 2 . In this study, a prototype of a new palette-type

Gul Buldu; Huseyin Canbolat; Mustafa Tutar

2011-01-01

293

System-reliability studies for wave-energy generation  

NASA Astrophysics Data System (ADS)

A study is reported that is being undertaken in the United Kingdom to determine means of developing the potential of the large wave-energy resource around the coast, in particular, that to the west facing the Atlantic. It is shown that derivation of the mean annual energy to be expected involved knowledge, not only of the wave climates, conversion efficiency characteristics of the proposed devices and of the power transmission system, but also of factors reflecting the availability overall. Attention is given to a simplified approach to the quantifying of reliability for each stage of the process. An appropriate method of analysis is established and a summary of the results obtained is given.

Dawson, J. M.; Din, S.; Mytton, M. G.; Shore, N. L.; Stansfield, H. B.

1980-06-01

294

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

SciTech Connect

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

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

2012-10-15

295

ENergy and Power Evaluation Program  

SciTech Connect

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.

NONE

1996-11-01

296

A powerful reflector in relativistic backward wave oscillator  

SciTech Connect

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.

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

2014-09-15

297

A powerful reflector in relativistic backward wave oscillator  

NASA Astrophysics Data System (ADS)

An improved TM021 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 TM021 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.

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

2014-09-01

298

Non-linear control of the ''clam'' wave energy device. Final report  

SciTech Connect

A promising wave energy device being currently investigated is the ''clam'' device. The clam extracts energy by pumping air through a specially designed (Wells) turbine. Although operation of the Wells turbine does not require a rectified air flow, some additional control will be necessary to optimize the phase of the clam motion for good efficiencies. An examination of the equation of motion in the time domain suggests the possibility of non-linear phase control by mechanical, power take-off, or pneumatic latching. Latching can be shown to increase the efficiency of the device in the longer wavelengths of the wave spectrum, i.e. those of high incident wave power.

Not Available

1983-09-01

299

Efficiency enhancement in high power backward-wave oscillators  

SciTech Connect

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.

Goebel, D.M.; Feicht, J.R. Adler, E.A. (Hughes Electron Dynamics, Torrance, CA (United States)); Ponti, E.S. (HRL Labs., Malibu, CA (United States)); Eisenhart, R.L. (Eisenhart and Associates, Woodland Hills, CA (United States)); Lemke, R.W. (Sandia National Labs., Albuquerque, NM (United States))

1999-06-01

300

A low-power wave union TDC implemented in FPGA  

SciTech Connect

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.

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

2011-10-01

301

In conventional accelerators, energy from RF electro-magnetic waves in vacuum is transformed into kinetic energy  

E-print Network

In conventional accelerators, energy from RF electro- magnetic waves in vacuum is transformed, they will equip scientists with powerful new capabilities for answering key questions. Those machines will also--to transform electromagnetic energy from a laser pulse into the kinetic energy of accelerated elec- trons

Geddes, Cameron Guy Robinson

302

Sorting and Parameterization of Observed Saturn and Jupiter Chorus Wave Power  

NASA Astrophysics Data System (ADS)

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.

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

2014-05-01

303

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

E-print Network

for power extraction from ocean waves will likely involve a periodic array of absorbing units. We reportBragg scattering and wave-power extraction by an array of small buoys By Xavier Garnaud & Chiang C to the potential of power extraction from sea waves by an isolated unit such as a buoy, a raft or an oscillating

Boyer, Edmond

304

Increasing hurricane wave power along the U.S. Atlantic and Gulf coasts  

E-print Network

Mode. The annual wave power at near-coastal locations is closely associated with open ocean WPIIncreasing hurricane wave power along the U.S. Atlantic and Gulf coasts Peter D. Bromirski1: Bromirski, P. D., and J. P. Kossin (2008), Increasing hurricane wave power along the U.S. Atlantic and Gulf

Kossin, James P.

305

Ecological Effects of Wave Energy Development in the Pacific Northwest  

E-print Network

Ecological Effects of Wave Energy Development in the Pacific Northwest A Scientific Workshop Technical Memorandum NMFS-F/SPO-92 #12;#12;Ecological Effects of Wave Energy Development in the Pacific......................................................................................................7 The Technology: Wave Energy Development on the West Coast Mirko Previsic, re vision consulting

306

Matching wave energy capacity and efficiency at part-load  

Microsoft Academic Search

There are growing provisions to expand ocean wave energy as an alternate renewable energy source. There are several challenges that need to be addressed before the technology gains full engineering and market confidence. One of the main technical hurdles is the need to address part-load problems of wave energy converters resulting from bathymetric conditions and variations in wave parameters such

A. Beyene; James H. Wilson

2004-01-01

307

Commercial Tapered Channel Wave Power Plants in Australia and Indonesia  

Microsoft Academic Search

paper presents the main features of Norwave's Tapered Channel (TAPCHAN) Technology. The technical details have previously been described elsewhere and are not repeated. A short, and inclomplete, overview of the wave energy research in Norway since 1970 is also given. The reporting on two projects in selected markets, Australia (Tasmania) and Indonesia, represents truly new information that has not been

Even Mehlum

1991-01-01

308

Available ocean wave power and prediction of power extracted by a contouring raft conversion system  

Microsoft Academic Search

Techniques are described which have been employed to develop detailed, quantitive estimates of the available ocean wave energy flux. A summary of results for a region of particular interest to potential U.S. developers of wave energy systems-the U.S. Northwest Pacific Coast - is also presented. Comparisons with results of other studies are made. In addition, a method for predicting the

E. L. Burdette; C. K. Gordon

1983-01-01

309

The impact of wave energy farms in the shoreline wave climate: Portuguese pilot zone case study using Pelamis energy wave devices  

Microsoft Academic Search

This paper describes the study of the impact of energy absorption by wave farms on the nearshore wave climate and, in special, the influence of the incident wave conditions and the number and position of the wave farms, on the nearshore wave characteristics is studied and discussed. The study was applied to the maritime zone at the West coast off

Artur Palha; Lourenço Mendes; Conceição Juana Fortes; Ana Brito-Melo; António Sarmento

2010-01-01

310

A Self-Regulating Heat Pump to Utilize Wind and Wave Energy Sources  

Microsoft Academic Search

Wind and wave energy devices produce their output in the form of shaft work, with a power output which varies over a wide range as the input energy intensity changes. For many processes (desalination, thermochemical processes, steam raising, space heating) energy is required in the form of heat. The conversion of shaft work directly to heat is thermodynamically very inefficient.

COLIN PRITCHARD; ROBERT LOW

1990-01-01

311

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

SciTech Connect

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.

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

2015-01-01

312

Net energy analysis: Powerful tool for selecting electric power options  

NASA Astrophysics Data System (ADS)

A number of net energy analysis studies have been conducted in recent years for electric power production from coal, oil and uranium fuels; synthetic fuels from coal and oil shale; and heat and electric power from solar energy. This technique is an excellent indicator of investment costs, environmental impact and potential economic competitiveness of alternative electric power systems for energy planners from the Eastern European countries considering future options. Energy conservation is also important to energy planners and the net energy analysis technique is an excellent accounting system on the extent of energy resource conservation. The author proposes to discuss the technique and to present the results of his studies and others in the field. The information supplied to the attendees will serve as a powerful tool to the energy planners considering their electric power options in the future.

Baron, S.

313

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

SciTech Connect

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.

Rhinefrank, Kenneth E.; Haller, Merrick C.; Ozkan-Haller, H. Tuba

2013-01-26

314

Control strategies to optimise power output in heave buoy energy convertors  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

315

Control strategy for AWS based wave energy conversion system  

Microsoft Academic Search

The controller for Archimedes wave swing (AWS) based wave energy conversion (WEC) system is designed in this paper. Based on the model of the AWS based WEC system in the d-q frame of reference, the control strategy of the WEC system under the irregular wave is derived. The AWS based WEC is regulated to be in resonance with the wave

F. Wu; X. P. Zhang; P. Ju

2010-01-01

316

Tidal energy in electric power systems  

Microsoft Academic Search

This paper discusses the uses and advantages of tidal energy in restructured power systems. The paper defines the resources as well as the ways in which tidal energy is converted into electricity. The paper also reviews a few tidal power projects around the world. It also shows the working of hydro tidal power plant. A comparative review of renewable energy

S. Sheth; M. Shahidehpour

2005-01-01

317

Enhanced RF extraction efficiency in high power traveling wave tubes  

NASA Astrophysics Data System (ADS)

We present results from an X-band relativistic TWT experiment in which the RF power is extracted in a coaxial output section. The two stage amplifier has a first stage that modulates the beam and a second stage with an iris-loaded circular slow wave structure tapered adiabatically to provide a low-reflection transition from the slow-wave structure to a circular waveguide. A coaxial inner conductor is inserted into the output tapered section and its' position and radius chosen to minimize reflections and maximize extracted RF power. The beam is dumped through an aperture in the inner conductor. It is shown both experimentally and through MAGIC simulations that a low reflection circular TM_01 to coaxial TEM mode transition can be made in this manner. In contrast to the traditional transverse extraction of power into a rectangular waveguide, the coaxial extraction is fairly broad-band and exhibits much lower sensitivity to dimensions. Presently, the power is extracted into the coaxial waveguide and absorbed into a tapered resistive load. Experimental results demonstrate 70 MW can be extracted for the full duration of the beam pulse; a significant increase over the 20 MW extracted previously, in cylindrical geometry. MAGIC simulations will be presented to extend these results to higher efficency TWTs by optimizing the bunching in the first stage of the amplifier.

Kerslick, G. S.; Naqvi, S.; Nation, J. A.; Schächter, L.

1996-11-01

318

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

NASA Technical Reports Server (NTRS)

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.

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

319

A generic outline for dynamic modeling of ocean wave and tidal current energy conversion systems  

Microsoft Academic Search

Ocean wave and tidal current resources bear immense potential for generating electric power in near future. This article discusses an outline of generic system modeling for the purpose of grid interconnection studies. Due emphasis has been given on ocean energy's current state of the art and mathematical formulations are developed to fit the possible future needs. Ocean power schemes are

Jahangir Khan; Ali Moshref; Gouri Bhuyan

2009-01-01

320

Analytical and experimental study of modified oscillating water column wave energy extraction systems  

Microsoft Academic Search

Numerous wave energy extraction devices have in the past, been proposed and modelled theoretically and physically. The power extraction of most devices occurs at a low efficiency. However, the primary deterrents to the utilization of these devices include the high capital cost per unit of generated power, the mechanical complexity in the harsh salt environment, the unworthiness in severe sea

K. C. Watts; H. C. Alexander; J. W. Graham; K. M. Hassan; S. N. Sarwal

1983-01-01

321

Modern Microwave and Millimeter-Wave Power Electronics  

NASA Astrophysics Data System (ADS)

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.

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

2005-04-01

322

Power combiner  

DOEpatents

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.

Arnold, Mobius; Ives, Robert Lawrence

2006-09-05

323

Review of the Novel Slow-Wave Structures for High-Power Traveling-Wave Tube  

Microsoft Academic Search

All-metal slow-wave structures are being paid great attention because of their advantages, such as good heat dissipation, high power capacity, wide passband, good wholeness of structure and large size etc. The emphases in this paper concentrate on the present state of study of four types of structures: helical groove, ring-plane, folded waveguide and periodically loaded waveguide, including theoretical analyses and

Wenxiang Wang; Yanyu Wei; Guofen Yu; Yubin Gong; Minzhi Huang; Guoqing Zhao

2003-01-01

324

Electromagnetic Waves - From X Rays to Radio Waves: The Energy of the Universe  

NASA Astrophysics Data System (ADS)

This book explores the world of electromagnetic waves ranging from radio frequencies to X-rays. The first part is physical and describes all the causes that produce electromagnetic waves in our world. The second part is astronomical and describes how electromagnetic waves are produced by astrophysical objects of different kinds, ranging from low-energy stars to high-energy objects such as pulsars and magnetars. The third part is devoted to some considerations concerning cosmology and the birth of electromagnetic waves.

Teodorani, M.

2008-09-01

325

On the dynamics of a novel ocean wave energy converter  

Microsoft Academic Search

Buoy-type ocean wave energy converters are designed to exhibit resonant responses when subject to excitation by ocean waves. A novel excitation scheme is proposed which has the potential to improve the energy harvesting capabilities of these converters. The scheme uses the incident waves to modulate the mass of the device in a manner which amplifies its resonant response. To illustrate

B. Orazov; O. M. O’Reilly; Ö. Savas

2010-01-01

326

Wave energy resource and technology assessment for coastal North Carolina  

Microsoft Academic Search

A preliminary assessment is presented of ocean wave energy conversion as an energy source for North Carolina. It considers the state's wave climate, the cost and performance of wave generating technologies now under development, and the potential impacts that these devices may have on the marine environment. It is the first evaluation that combines these three aspects for a specific

G. Hagerman; B. Zickefoose; T. Heller

1989-01-01

327

Deep ocean wave energy conversion using a cycloidal turbine  

Microsoft Academic Search

A lift based wave energy converter, namely, a cycloidal turbine, is investigated. This type of wave energy converter consists of a shaft with one or more hydrofoils attached eccentrically at a radius. The main shaft is aligned parallel to the wave crests and submerged at a fixed depth. In the two-dimensional limit, i.e. for large spans of the hydrofoil (or

S. G. Siegel; T. Jeans; T. E. McLaughlin

2011-01-01

328

Purely Nonlinear Instability of Standing Waves with Minimal Energy  

E-print Network

Purely Nonlinear Instability of Standing Waves with Minimal Energy ANDREW COMECH University(1) symmetry. We prove that in the generic situation the standing wave that has the minimal energy among all other standing waves is unstable, in spite of the absence of linear instability. Essentially

Comech, Andrew

329

Purely Nonlinear Instability of Standing Waves with Minimal Energy  

E-print Network

Purely Nonlinear Instability of Standing Waves with Minimal Energy ANDREW COMECH University(1) symmetry. We prove that in the generic situation the standing wave that has the minimal energy among all other standing waves is unstable, in spite of the absence of linear instability. Essen- tially

Pelinovsky, Dmitry

330

Internal energy relaxation in shock wave structure  

SciTech Connect

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.

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

2013-12-15

331

Hydro, tidal and wave energy in Australia  

Microsoft Academic Search

The three renewable energy technologies discussed in this paper are based on water, but differ markedly in terms of the size of the available potential resource, the maturity of the associated conversion technologies, the extent to which they have been exploited to date, and the current research effort being devoted to their future development. Hydro-electricity and tidal power are both

David Harries; Mark McHenry; Philip Jennings; Chacko Thomas

2006-01-01

332

Effects of half-wave and full-wave power source on the anodic oxidation process on AZ91D magnesium alloy  

NASA Astrophysics Data System (ADS)

Anodic films have been prepared on the AZ91D magnesium alloys in 1 mol/L Na 2SiO 3 with 10 vol.% silica sol addition under the constant voltage of 60 V at room temperature by half-wave and full-wave power sources. The weight of the anodic films has been scaled by analytical balance, and the thickness has been measured by eddy current instrument. The surface morphologies, chemical composition and structure of the anodic films have been characterized by scanning electron microscopy (SEM), energy dispersion spectrometry (EDS), X-ray diffraction (XRD) and transmission electron microscopy (TEM). The results show that the thickness and weight of the anodic films formed by the two power sources both increase with the anodizing time, and the films anodized by full-wave power source grow faster than that by half-wave one. Furthermore, we have fitted polynomial to the scattered data of the weight and thickness in a least-squares sense with MATLAB, which could express the growth process of the anodic films sufficiently. The full-wave power source is inclined to accelerate the growth of the anodic films, and the half-wave one is mainly contributed to the uniformity and fineness of the films. The anodic film consists of crystalline Mg 2SiO 4 and amorphous SiO 2.

Wang, Ximei; Zhu, Liqun; Li, Weiping; Liu, Huicong; Li, Yihong

2009-03-01

333

Careers in Geothermal Energy: Power from below  

ERIC Educational Resources Information Center

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,…

Liming, Drew

2013-01-01

334

The role power electronics in future energy systems and green industrialization  

Microsoft Academic Search

One important aspect of clean energy or green industrialization is the search for technologies (CTpsilas) that can reduce the major environmental impact of present energy sources. Alternative energy sources (AES) like micro-turbines, photovoltaic (PV), fuel cells, wave energy and wind turbines seem to meet the requirement for clean energy. Integrating these on-site generating sources into the larger electric power system

M. Elbuluk; N. R. N. Idris

2008-01-01

335

Mapping and Assessment of the United States Ocean Wave Energy Resource  

SciTech Connect

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.

Paul T. Jacobson; George Hagerman; George Scott

2011-12-01

336

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

E-print Network

-Stream Power Demonstrated Robert Keith Smith, Pulse Tidal!! For more than a year, Pulse Tidal has been operating a grid-connected tidal- stream power demonstration device that delivers cost-effective energy on the technology itself, but the technology must also demonstrate financial viability. Cost-Effective Tidal

337

Energy extraction from ocean currents and waves: Mapping the most promising locations  

NASA Astrophysics Data System (ADS)

Concerns about fossil fuel supplies and an ever-increasing demand for energy have prompted the search for alternative power sources. One option is the ocean, a power-dense and renewable source of energy, but its capacity to meet human energy demands is poorly understood. Although raw wave energy resources have been investigated at many scales, there is still substantial uncertainty regarding how much useful power can be extracted. Even less is known about the energy available in ocean currents, especially on a global scale. Moreover, no studies have attempted to examine wave and current energy simultaneously while at the same time taking into account geographical, environmental, and technical factors that can substantially limit the amount of extractable energy. In this study, we use high fidelity oceanographic model data to assess the availability, recoverability, and value of energy in ocean wind waves and currents. Global wave energy transport, coastal wave energy flux, and current energy are calculated and mapped using the model data. These maps are then incorporated into a geographic information system (GIS) in order to assess the U.S. recoverable ocean energy resource. In the GIS, the amount of recoverable energy is estimated by combining the power output from realistic wave and current energy farms with physical and ecological data such as bathymetry and environmentally protected areas. This holistic approach is then used to examine the distribution and value of extractable wave and current energy along the U.S. coast. The results support previous studies that show that the U.S. West Coast has large potential for wave energy extraction and that the Florida Strait has high potential for current energy extraction. We also show that, at any particular location, the amount of available ocean energy is only one factor of many that determines the ultimate feasibility and value of the energy. We outline ways in which the GIS framework used in this assessment can be enhanced to better model the many variables that affect the value of ocean energy; future research in this area may lead to greater support for developing, testing, and deploying ocean energy converter technology.

Ordonez, A.; Hamlington, P.; Fox-Kemper, B.

2012-12-01

338

Experimental determination of radiated internal wave power without pressure field data  

SciTech Connect

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.

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

2014-04-15

339

Experimental determination of radiated internal wave power without pressure field data  

NASA Astrophysics Data System (ADS)

We present a method to determine, using only velocity field data, the time-averaged energy flux left<{J}right> and total radiated power P for two-dimensional internal gravity waves. Both left<{J}right> 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.

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

2014-04-01

340

Design of stabilization system for medium wave infrared laser power  

NASA Astrophysics Data System (ADS)

The 3~5um Medium Wave Infrared(MWIR) laser has gained a lot of attention for its important application values in remote sensing, medical, military and many other fields. However, there are many technical difficulties to fabricate those kind lasers, and the performance of their output power stabilities remain to be improved. In a practical application, the MWIR's output power will be instability when the temperature changes and the current varies. So a system of reducing MWIR power fluctuation should be established. In this paper, a photoelectric system of stabilizing the output power of He-Ne laser is developed, which is designed based on the theory of feedback control. Some primary devices and technologies are presented and the functions of each module are described in detail. Among of those, an auxiliary visible light path is designed to aid to adjust WMIR optical system. A converging lens as spatial filter is employed to eliminate stray light well. Dewar temperature control equipment is also used to reduce circuit noise in IR detector. The power supply of AD conversion circuit is independently designed to avoid the crosstalk caused by the analog section and digital section. Then the system has the advantages of good controllability, stability and high precision after above designation. Finally, the measurement precision of the system is also analyzed and verified.

Ding, Zhong-kui; Wang, Lin; Shi, Xue-shun; Xu, Jun

2013-12-01

341

An atlas of the wave-energy resource in Europe  

SciTech Connect

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

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

1996-11-01

342

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

E-print Network

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

Texas at Austin. University of

343

Modeling wave power extraction devices will help engineers identify best design  

E-print Network

makes it easier to evaluate methods for harnes- sing the power of ocean waves to generate electricityModeling wave power extraction devices will help engineers identify best design December 2009 that could help reduce the world's dependence on fossil fuels. Photo / Jon Sullivan PROBLEM Ocean waves could

Entekhabi, Dara

344

Methodology for estimating wave power potential in places with scarce instrumentation in the Caribbean Sea  

Microsoft Academic Search

There are great difficulties in properly evaluating the power present in the waves in the Caribbean due to of the scarcity of marine instrumentation and the reduced length of the existing records. This research aims to design a new methodology for estimating wave power potential in places lacking instrumentation by using reanalysis winds and wave generation models to generate hourly

Santiago Ortega; Andres F. Osorio; Pablo Agudelo-Restrepo; Jaime I. Velez

2011-01-01

345

Ulysses Observations of Magnetic Waves Due to Newborn Interstellar Pickup Ions. II. Application of Turbulence Concepts to Limiting Wave Energy and Observability  

NASA Astrophysics Data System (ADS)

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.

Cannon, Bradford E.; Smith, Charles W.; Isenberg, Philip A.; Vasquez, Bernard J.; Joyce, Colin J.; Murphy, Neil; Nuno, Raquel G.

2014-06-01

346

Alternative Energy and Remote Power Products  

NSDL National Science Digital Library

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

347

Performance optimization of a pneumatic wave energy conversion device  

NASA Astrophysics Data System (ADS)

The purpose of this study was, for the first time, to optimize the performance of a pneumatic wave energy conversion device. The experiments of Jolly and Newmaster (1979) and Trop and Casey (1980) left a capture chamber and turbine for further investigation. To optimize the system performance the turbine had to be first analyzed so that its power performance curves could be determined. These curves were needed to help define the possible overall performance of the system, and for the impedance matching of the system necessary for performance optimization. With this knowledge, an appropriate generator was purchased and a generator-turbine linkage designed and built. The completed system was then analyzed in the 380 ft wave tank at the U.S. Naval Academy to establish its optimum performance. From the research it is clear that pneumatic wave energy conversion is a promising concept. With several hundred of these devices situated some 100 km off the coast of the Pacific Northwest each device would be producing from 50 to 200 kW which would be transferred back to shore.

Surko, S. W.

1982-08-01

348

Speech articulator measurements using low power EM-wave sensors  

SciTech Connect

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.}

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

1998-01-01

349

Wave Glider Autonomous Surface Vehicle Applications and Missions  

E-print Network

. There is substantial power available in ocean waves, and the Wave Glider harnesses this power to maintain an average of ocean wave energy into forward thrust, independent of wave direction. The wave energy propulsion system and 650 Watt hours of battery capacity to power on board sensors and payloads. This new class of wave

Frandsen, Jannette B.

350

Spectral wave flow attenuation within submerged canopies: Implications for wave energy dissipation  

Microsoft Academic Search

Communities of benthic organisms can form very rough surfaces (canopies) on the seafloor. Previous studies have shown that an oscillatory flow induced by monochromatic surface waves will drive more flow inside a canopy than a comparable unidirectional current. This paper builds on these previous studies by investigating how wave energy is attenuated within canopies under spectral wave conditions, or random

Ryan J. Lowe; James L. Falter; Jeffrey R. Koseff; Stephen G. Monismith; Marlin J. Atkinson

2007-01-01

351

Experimental study of ultrasonic beam sectors for energy conversion into Lamb waves and Rayleigh waves.  

PubMed

When a bounded beam is incident on an immersed plate Lamb waves or Rayleigh waves can be generated. Because the amplitude of a bounded beam is not constant along its wave front, a specific beam profile is formed that influences the local efficiency of energy conversion of incident sound into Lamb waves or Rayleigh waves. Understanding this phenomenon is important for ultrasonic immersion experiments of objects because the quality of such experiments highly depends on the amount of energy transmitted into the object. This paper shows by means of experiments based on monochromatic Schlieren photography that the area within the bounded beam responsible for Lamb wave generation differs from that responsible for Rayleigh wave generation. Furthermore it provides experimental verification of an earlier numerical study concerning Rayleigh wave generation. PMID:24079915

Declercq, Nico Felicien

2014-02-01

352

Networks of Triboelectric Nanogenerators for Harvesting Water Wave Energy: A Potential Approach toward Blue Energy.  

PubMed

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

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

2015-03-24

353

Energy storage systems for advanced power applications  

Microsoft Academic Search

While energy storage technologies do not represent energy sources, they provide valuable added benefits to improve stability power quality, and reliability of supply. Battery technologies have improved significantly in order to meet the challenges of practical electric vehicles and utility applications. Flywheel technologies are now used in advanced nonpolluting uninterruptible power supplies. Advanced capacitors are being considered as energy storage

PAULO F. RIBEIRO; BRIAN K. JOHNSON; MARIESA L. CROW; AYSEN ARSOY; YILU LIU

2001-01-01

354

Wave Energy Test Site (WETS) Marine Corps Base Hawaii (MCBH)  

E-print Network

Wave Energy Test Site (WETS) Marine Corps Base Hawaii (MCBH) Alexandra DeVisser, NAVFAC-EXWC Brian Cable, Sound & Sea Technology (SST) Luis A. Vega, HNEI-University of Hawaii Energy Ocean International June 10, 2013 #12;Wave Energy Test Site (WETS) Objective: Provide location for year-long in

355

Bonneville Power Administration's Purchasing of Energy Savings  

E-print Network

BONNEVILLE POWER ADMINISTRATION'S PURCHASE OF ENERGY SAVINGS Harold (Skip) Schick Leslie E. McMillan Bonneville Power Administration Port1and, Oregon INTRODUCTION The Bonneville Power Administration (BPA) is conducting a commercial... of several activities BPA is conductin9 to develop the capabil ity to conserve energy in the com mercial sector of electrical energy use. This paper describes the benefits of the approach, the program des ign, 1essons 1earned through field testing...

Schick, H.

356

Energy of Water Waves Induced by Submarine Landslides  

Microsoft Academic Search

Water waves generated by submarine landslides may constitute a serious hazard for coastal population and environment. These masses may be giant, as documented by several examples in recent history and by numerous geological traces of paleo-events. A theoretical investigation on wave generation and wave energy is performed here by using a model that is based on some simplifying assumptions. The

S. Tinti; E. Bortolucci

2000-01-01

357

On the Use of Computational Models for Wave Climate Assessment in Support of the Wave Energy Industry  

E-print Network

, or as boundary conditions to a more detailed model. A case study of the wave climate of Hesquiaht Sound, BritishOn the Use of Computational Models for Wave Climate Assessment in Support of the Wave Energy On the Use of Computational Models for Wave Climate Assessment in Support of the Wave Energy Industry

Victoria, University of

358

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

SciTech Connect

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.

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

1982-09-28

359

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

SciTech Connect

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.

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

360

Long time scale evolution of high-power radio wave ionospheric heating 1. Beam propagation  

Microsoft Academic Search

The long time scale evolution, that is, for times long compared to an electron collision period of high-power radio wave ionospheric heating, is studied. Preliminary studies are made to model high-power radio wave propagation in an ionosphere containing a dynamically produced electron density cavity. We show that high-power radio wave-induced plasma density depletions in the F region ionosphere will convect

M. J. Keskinen; P. K. Chaturvedi; S. L. Ossakow

1993-01-01

361

Long time scale evolution of high-power radio wave ionospheric heating. 1. Beam propagation  

Microsoft Academic Search

The long time scale evolution, that is, for times long compared to an electron collision period of high-power radio wave ionospheric heating, is studied. Preliminary studies are made to model high-power radio wave propagation in an ionosphere containing a dynamically produced electron density cavity. We show that high-power radio wave-induced plasma density depletions in the F region ionosphere will convect

M. J. Keskinen; P. K. Chaturvedi; S. L. Ossakow

1993-01-01

362

Assessment of the changes induced by a wave energy farm in the nearshore wave conditions  

NASA Astrophysics Data System (ADS)

Starting from the observation that an important next stage in exploiting the ocean energy is to install large arrays of several identical devices in order to raise their overall electricity production, the present work has as objective to assess the local and coastal impact of a large wave farm that would operate in the Portuguese coastal environment. The target area is the Portuguese maritime pilot zone, São Pedro de Moel, which is located in the central part of the Portuguese continental nearshore. A generic wave farm was considered and various transmission situations were analyzed. The study started with the situation without wave farm (zero absorption) and subsequently different scenarios were considered by gradually increasing the conditions to the hypothetic case of the total absorption. For each case study, model simulations were performed covering the entire year 2009 using a wave prediction system based on Wave Watch 3, for the wave generation at the level of the entire North Atlantic Ocean, and on SWAN, for the coastal wave transformation. In this way, a comprehensive picture of the possible impact of the wave farm is provided. The results show that the presence of a wave farm operating offshore has a strong influence on the wave conditions immediately down wave. Although this influence is usually attenuated at the level of the coastline, it appears as obvious a general decrease in terms of significant wave height due to the wave farm, but also some other wave parameters are modified.

Bento, A. Rute; Rusu, Eugen; Martinho, Paulo; Guedes Soares, C.

2014-10-01

363

Wave-powered small-scale generation systems for ocean exploration  

Microsoft Academic Search

This paper describes our initial investigation of an inertial power generation system, designed for use in small, low-power, long-endurance ocean exploration robots. The system recovers small amounts of power from the movements caused by ocean waves. The primary focus of the investigation to date has been the development of efficient power recovery system electronics that extract useful power from a

Phill Brown; D. Hardisty; T. C. A. Molteno

2006-01-01

364

Renewable Energy Powered Water Treatment Systems   

E-print Network

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, ...

Richards, Bryce S.; Schäfer, Andrea

2009-01-01

365

Energy function analysis for power system stability  

Microsoft Academic Search

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

M. A. Pai

1989-01-01

366

Performance of large arrays of point absorbing direct-driven wave energy converters  

NASA Astrophysics Data System (ADS)

Future commercial installation of wave energy plants using point absorber technology will require clusters of tens up to several hundred devices, in order to reach a viable electricity production. Interconnected devices also serve the purpose of power smoothing, which is especially important for devices using direct-driven power take off. The scope of this paper is to evaluate a method to optimize wave energy farms in terms of power production, economic viability, and resources. In particular, the paper deals with the power variation in a large array of point-absorbing direct-driven wave energy converters, and the smoothing effect due to the number of devices and their hydrodynamic interactions. A few array geometries are compared and 34 sea states measured at the Lysekil research site at the Swedish west coast are used in the simulations. Potential linear flow theory is used with full hydrodynamic interactions between the buoys. It is shown that the variance in power production depends crucially on the geometry of the array and the number of interacting devices, but not significantly on the energy period of the waves.

Engström, J.; Eriksson, M.; Göteman, M.; Isberg, J.; Leijon, M.

2013-11-01

367

Internal wave energy dissipation: near and far, where and how?  

NASA Astrophysics Data System (ADS)

Global patterns of diapycnal mixing in the ocean interior are largely set by the geography of internal wave generation, propagation, and dissipation. One of the largest open questions is what percentage of internal waves dissipate near their generation sites (e.g. over the rough topography where internal tides are generated) and what percentage escapes, breaking thousands of kilometers away. Here we attempt to constrain these percentages using a combination of analytical models of wave generation, global internal wave numerical models, and a uniquely comprehensive microstructure dataset. Though microstructure data continues to be under-sampled, available data is consistent with an interpretation that roughly half of generated internal wave energy is dissipated within the interior of ocean basins, leaving the rest to dissipate where low-mode waves encounter continental margins. At the margins, loss of internal wave energy varies depending on the reflectivity of the continental slope to the internal wave modes. Using energy fluxes calculated from a global internal-wave model, and the reflectivity of mode-1 waves at the slopes, we make initial estimates of the lateral dependence of internal-wave energy loss along the continental slopes.

Waterhouse, A. F.; Kelly, S. M.; Simmons, H. L.; Alford, M. H.; MacKinnon, J. A.; Nash, J. D.

2012-12-01

368

Compilers for Power andCompilers for Power and Energy ManagementEnergy Management  

E-print Network

Compilers for Power andCompilers for Power and Energy ManagementEnergy Management Ulrich (UlrichISLPED'02 August 13, 2002 6 3RZHU3RZHU YVYV (QHUJ\\ (QHUJ\\ SRZHU DFWLYLW\\ OHYHO DW D JLYHQ SRLQW LQ WLPH HQHUJ\\ WRWDO DPRXQW RI DFWLYLW\\ time power time power VDPH HQHUJ\\ GLIIHUHQW SHDN#12; SRZHU RSWLPL

Kremer, Ulrich

369

Thermal energy storage for power plant applications  

Microsoft Academic Search

This study was conducted by Pacific Northwest Laboratory (PNL) to evaluate alternative methods of using coal to generate peak and intermediate load power. The approach was to review the technical and economic feasibility of using thermal energy storage (TES) with a conventional coal-fired power plant and an integrated gasification combined cycle (IGCC) power plant. In the first case, conventional pulverized

S. Somasundaram; M. K. Drost; Z. I. Antoniak; D. R. Brown

1990-01-01

370

Coordinated Management: Power, Performance, Energy, and Temperature  

E-print Network

with shorter time constants, such as current spikes in the power distribution network, and longer intervalsCoordinated Management: Power, Performance, Energy, and Temperature Heather Hanson Stephen W at Austin IBM Technical Contact : Rob Bell, Jr. Abstract We are developing a next-generation power manager

Keckler, Stephen W.

371

Loss of energy of internal solitary wave over underwater obstacle  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

372

Experimental study on a pendulum wave energy converter  

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

373

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

USGS Publications Warehouse

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.

Adams, P.; Ruggiero, P.

2006-01-01

374

Power Amplifier Module with 734-mW Continuous Wave Output Power  

NASA Technical Reports Server (NTRS)

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.

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

375

Power Spectrum of Gravitational Waves from Unbound Compact Binaries  

NASA Astrophysics Data System (ADS)

Unbound interacting compact binaries emit gravitational radiation in a wide frequency range. Since short burst-like signals are expected in future detectors, such as LISA or advanced LIGO, it is interesting to study their energy spectrum and the position of the frequency peak. Here we derive them for a system of massive objects interacting on hyperbolic orbits within the quadrupole approximation, following the work of Capozziello et al. In particular, we focus on the derivation of an analytic formula for the energy spectrum of the emitted waves. Within numerical approximation our formula is in agreement with the two known limiting cases: for the eccentricity ? = 1, the parabolic case, whose spectrum was computed by Berry and Gair, and the large ? limit with the formula given by Turner.

De Vittori, L.; Jetzer, P.; Klein, A.

2013-01-01

376

Wave turbulence revisited: Where does the energy flow?  

E-print Network

Turbulence in a system of nonlinearly interacting waves is referred to as wave turbulence. It has been known since seminal work by Kolmogorov, that turbulent dynamics is controlled by a directional energy flux through the wavelength scales. We demonstrate that an energy cascade in wave turbulence can be bi-directional, that is, can simultaneously flow towards large and small wavelength scales from the pumping scales at which it is injected. This observation is in sharp contrast to existing experiments and wave turbulence theory where the energy flux only flows in one direction. We demonstrate that the bi-directional energy cascade changes the energy budget in the system and leads to formation of large-scale, large-amplitude waves similar to oceanic rogue waves. To study surface wave turbulence, we took advantage of capillary waves on a free, weakly charged surface of superfluid helium He-II at temperature 1.7K. Although He-II demonstrates non-classical thermomechanical effects and quantized vorticity, waves on its surface are identical to those on a classical Newtonian fluid with extremely low viscosity. The possibility of directly driving a charged surface by an oscillating electric field and the low viscosity of He-II have allowed us to isolate the surface dynamics and study nonlinear surface waves in a range of frequencies much wider than in experiments with classical fluids.

L. V. Abdurakhimov; I. A. Remizov; A. A. Levchenko; G. V. Kolmakov; Y. V. Lvov

2014-04-03

377

Power electronics and alternative energy generation  

Microsoft Academic Search

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

James P Lyons; Vlatko Vlatkovic

2004-01-01

378

ENERGY, POWER AND ENVIRONMENT (Environmental Analytical Chemistry)  

E-print Network

the development of society has been intertwined with quest for sources of energy and power. In the middleENERGY, POWER AND ENVIRONMENT (Environmental Analytical Chemistry) CHEM 6284/CHEM 4803 Fall 2014 3 of radiation with matter; measurement of radiation; nuclear reactions; 9/30 10/2-9 Midterm Health effects

Sherrill, David

379

Solar energy thermally powered electrical generating system  

NASA Technical Reports Server (NTRS)

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.

Owens, William R. (Inventor)

1989-01-01

380

Enhancement of particle-wave energy exchange by resonance sweeping  

SciTech Connect

When the resonance condition of the particle-wave interaction is varied adiabatically, the particles trapped in a wave are found to form phase space holes or clumps that enhance the particle-wave energy exchange. This mechanism can cause increased saturation levels of instabilities and even allow the free energy associated with instability to be tapped in a system in which background dissipation suppresses linear instability.

Berk, H.L.; Breizman, B.N.

1996-01-01

381

Enhancement of particle-wave energy exchange by resonance sweeping  

SciTech Connect

It is shown that as the resonance condition of the particle-wave interaction is varied adiabatically, that the particles trapped in the wave will form phase space holes or clumps that can enhance the particle-wave energy exchange. This mechanism can cause much larger saturation levels of instabilities, and even allow the free energy associated with instability, to be tapped in a system that is linearly stable due to background dissipation.

Berk, H.L.; Breizman, B.N.

1995-10-01

382

Energy Transport by Nonlinear Internal Waves  

Microsoft Academic Search

Wintertime stratification on Oregon's continental shelf often produces a near-bottom layer of densefluid that acts as an internal waveguide on 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 are highly turbulent (instantaneous bed stresses are 1 N m 2), resuspending bottom sediments

J. N. Moum; J. M. Klymak; J. D. Nash; A. Perlin; W. D. Smyth

2007-01-01

383

Nuclear Power Trends Energy Economics and Sustainability  

E-print Network

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

384

Evaluation of a sea wave energy converter with variable trim  

Microsoft Academic Search

In this paper, the working principles of an innovative sea-wave energy converter are described together with an analysis of the effectiveness of a generic site installation. The system presented is the evolution of a project born in 1994 with the aim of designing a sea wave energy device with variable trim, able to adjust its behaviour to the sea conditions.

L. Martellucci

1997-01-01

385

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

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

386

High power continuous-wave titanium:sapphire laser  

DOEpatents

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).

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

387

High power continuous-wave titanium:sapphire laser  

DOEpatents

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.

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

1993-09-21

388

The hydrodynamics of a wave-power device in a tapered harbor  

SciTech Connect

This paper considers the hydrodynamic performance of a single wave-power device placed at the end of a tapered harbor and set in a reflecting coastline. A relatively simple model, in which the harbor width is assumed to be much smaller than the incident wavelength, is used to calculate approximate values for the hydrodynamic coefficients and hence determine the energy absorbing capabilities of the device. A comparison is presented between a device in a rectangular harbor and one in a tapered harbor in order to make a preliminary assessment of the influence of the taper.

Gallachoir, B.P.O.; Thomas, G.P. [University College, Cork (Ireland). Dept. of Mathematical Physics; Sarmento, A.J.N.A. [Instituto Superior Tecnico, Lisbon (Portugal). Dept. de Engenharia Mecanica

1995-12-31

389

Ocean wave energy overview and research at Oregon State University  

Microsoft Academic Search

The solutions to today's energy challenges need to be explored through alternative, renewable and clean energy sources to enable a diverse national energy resource plan. An extremely abundant and promising source of energy exists in the world's oceans. Ocean energy exists in the forms of wave, tidal, marine currents, thermal (temperature gradient) and salinity. Among these forms, significant opportunities and

Ted K. A. Brekken; Annette von Jouanne; Hai Yue Han

2009-01-01

390

Low-frequency square-wave electronic ballast with resonant ignition using digital mode and power  

E-print Network

Low-frequency square-wave electronic ballast with resonant ignition using digital mode and power square wave inverter for normal operation. Ignition is achieved by resonance when the converter as a LF square wave inverter by controlling the FB to act alternately as a Buck converter supplying

391

Powerful surface-wave oscillators with two-dimensional periodic structures  

SciTech Connect

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

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

2012-04-02

392

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

E-print Network

heat mainly electrons through Coulomb collisions. However, in the presence of appro- priate waves functions than mere electron heating. The amplification of the waves can occur if there is a pop- ulationALPHA POWER CHANNELLING WITH TWO WAVES N.J. FISCH, M.C. HERRMANN Princeton Plasma Physics

393

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

Microsoft Academic Search

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

Frank Hegeler; Chris Grabowski; Edl Schamiloglu

1998-01-01

394

A time-domain numerical simulator for oscillating water column wave power plants  

Microsoft Academic Search

This paper presents a time-domain numerical simulator of oscillating water column (OWC) wave power plants. The whole problem (the simulation of the movements of the inner free surface due to the excitation of the outer sea-waves) is split into two subproblems: an outer one, dealing with the incident, diffracted and radiated waves, solved once for all, and an inner one,

C. Josset; A. H. Clément

2007-01-01

395

Compact inductive energy storage pulse power system  

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

396

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

397

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

NASA Technical Reports Server (NTRS)

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.

Manning, Robert M.

1993-01-01

398

Electromagnetic energy storage and power dissipation in nanostructures  

NASA Astrophysics Data System (ADS)

The processes of storage and dissipation of electromagnetic energy in nanostructures depend on both the material properties and the geometry. In this paper, the distributions of local energy density and power dissipation in nanogratings are investigated using the rigorous coupled-wave analysis. It is demonstrated that the enhancement of absorption is accompanied by the enhancement of energy storage both for material at the resonance of its dielectric function described by the classical Lorentz oscillator and for nanostructures at the resonance induced by its geometric arrangement. The appearance of strong local electric field in nanogratings at the geometry-induced resonance is directly related to the maximum electric energy storage. Analysis of the local energy storage and dissipation can also help gain a better understanding of the global energy storage and dissipation in nanostructures for photovoltaic and heat transfer applications.

Zhao, J. M.; Zhang, Z. M.

2015-01-01

399

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

E-print Network

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

400

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

E-print Network

/read/wave-goodbye-to-flat-batteries-tiny-windmills-could-... #12;14 Social Security Benefits You Haven't Been Taking Moneynews Secrets of Building Muscle: ItWave goodbye to flat batteries: tiny windmills could power smartphones on the go by Matthew Jarvis them on a sleeve for your smartphone," Chiao said. "When the phone is out of battery power, all you

Chiao, Jung-Chih

401

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

E-print Network

Generation of Alfve´n waves by high power pulse at the electron plasma frequency B. Van Compernolle 2005; published 19 April 2005. [1] The interaction of a short high power pulse at the electron plasmaG, Helium) capable of supporting Alfve´n waves has been studied. The interaction leads to the generation

California at Los Angles, University of

402

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

E-print Network

in the solar wind and magnetotail Here we present observations of EM wave magnetic power during bow shockElectromagnetic Wave Power Observed Near the Moon during Terrestrial Bow Shock Crossings and Its@ssl.berkeley.edu), G. T. Delory1, J. S. Halekas1, and R. E. Grimm2 1Space Sciences Laboratory, University of California

Fillingim, Matthew

403

Performance optimization of a pneumatic wave energy conversion device. Final report 1981-1982  

Microsoft Academic Search

The purpose of this study was, for the first time, to optimize the performance of a pneumatic wave energy conversion device. The experiments of Jolly and Newmaster (1979) and Trop and Casey (1980) left a capture chamber and turbine for further investigation. To optimize the system performance the turbine had to be first analyzed so that its power performance curves

Surko

1982-01-01

404

Preliminary analysis of wave energy conversion at an offshore structure. Final report  

Microsoft Academic Search

A study of the feasibility of utilizing wave energy to provide the electrical power to operate the Buzzards Bay Light Tower has been carried out. It was concluded that a pneumatic buoy attached to the light tower would be the best solution. Experiments were conducted in the MIT Towing Tank to estimate the performance of such a device. The loads

A. D. Carmichael; D. Assanis; J. O. Salsich

1982-01-01

405

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

E-print Network

of Meteorology, University of Hawaii at Manoa, Honolulu, HI 96822, USA c National Marine Renewable Energy Center Elsevier Ltd. All rights reserved. 1. Introduction The Earth's changing climate, the increasing cost of oil the world Hawaii is known for its powerful waves and its marine recreational activities. Hidden

406

Comparison of fractional wave equations for power law attenuation in ultrasound and elastography.  

PubMed

A set of wave equations with fractional loss operators in time and space are analyzed. The fractional Szabo equation, the power law wave equation and the causal fractional Laplacian wave equation are all found to be low-frequency approximations of the fractional Kelvin-Voigt wave equation and the more general fractional Zener wave equation. The latter two equations are based on fractional constitutive equations, whereas the former wave equations have been derived from the desire to model power law attenuation in applications like medical ultrasound. This has consequences for use in modeling and simulation, especially for applications that do not satisfy the low-frequency approximation, such as shear wave elastography. In such applications, the wave equations based on constitutive equations are the viable ones. PMID:24433745

Holm, Sverre; Näsholm, Sven Peter

2014-04-01

407

Wave spectral energy variability in the northeast Pacific  

USGS Publications Warehouse

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.

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

2005-01-01

408

Wave energy gradients and shoreline change on Vabbinfaru platform, Maldives  

NASA Astrophysics Data System (ADS)

This study examined coral reef platform wave processes and shoreline dynamics over short timescales. Wave energy gradients and shoreline change were measured over a 3-week period on Vabbinfaru platform, North Malé Atoll, Maldives, during the westerly monsoon in June 2010. Wave processes were measured using nine pressure sensors recording near continuous data for 19 days around the reef and shoreline of a small circular sand cay. Toe of beach position was surveyed before, during and after the deployment to map changes in shoreline configuration. Results show that wave height and direction on the windward reef are closely controlled by local wind activity inside the atoll lagoon. Wave transformation across the platform was found to exhibit strong tidal modulation and results in distinct cross-reef energy zonation. Results are presented by comparing two contrasting boundary wind conditions: the first 2 weeks characterised by moderate southwest winds, and the third week characterised by stronger northwest winds. Wave data was interpolated to platform scale and used to show spatial variations in energy exposure during the different boundary conditions. Under southwest winds, greatest wave energy was present on the western and leeward (eastern) reefs, driving an energy gradient towards the sheltered northern and southern shorelines. A net 4.5% increase in beach area was measured during this period. During stronger northwest winds, higher wave energy impacted the reef and was concentrated on the western reef, northern reef and northwest shoreline. An energy gradient formed around the island towards a low energy zone located at the southeast shoreline. Significant shoreline change occurred during this period with the toe of beach retreating landward by more than 10 m on the northwest, northeast and southwest of Vabbinfaru Island. Beach area was reduced by 3761 m2 (17%) as the shoreline was forced to adjust in response to a new hydrodynamic regime. Results show that the coral reef platform is able to modify and filter the incident wave climate, resulting in marked spatial differences in wave spectra. Spatial differences in wave energy are sensitive to local wind activity, resulting in rapid alteration in wave energy distribution around the platform. Results highlight that reef island shorelines are morphologically sensitive to short-term changes in boundary wind and wave conditions. Wave energy gradients driven by local wind activity have the potential to drive alongshore fluxes of sediment around island shorelines. Therefore, changes to the process regime can result in disequilibrium of the shoreline, forcing rapid adjustment of island sediment.

Beetham, Edward Paul; Kench, Paul Simon

2014-03-01

409

Approach warning system for snowplow using aerial-high-power ultrasonic wave with radio wave  

NASA Astrophysics Data System (ADS)

An approach warning system for a snowplow and guide was developed by using aerial-high-power ultrasonic transducer. To be robust against some serious factors in winter, ultrasonic signal and radio one were combined on the system, and the flat face side of stepped circular vibrating plate was utilized as a radiation plate. The ultrasonic wave radiated from the flat face side still had a better directivity, and the flat face had advantage to prevent bad influences from water, snow or ice. From experiment results, when double transducers were set on both sides of roof of snowplow, this system was able to be measure distance between a guide and snowplow in whole of controlled area.

Manabu, Aoyagi; Yuta, Amagi; Hiroaki, Miura; Okeya, Ryota; Hideki, Tamura; Takehiro, Takano

2012-05-01

410

Fabrication of bulk ceramics by high power millimeter-wave radiation  

Microsoft Academic Search

High power 28GHz millimeter-wave radiation was applied to the fabrication of bulk AlN, Si3N4 and Al2O3. The millimeter-wave radiation enables to sinter these ceramics rapidly at several 100°C lower temperature than the conventional method. The rapid sintering is attributed to the enhancement of atomic migration due to the “non-thermal effect” of millimeter-wave. It is indicated that the millimeter-wave radiation can

Y. Makino; T. Ueno; T. Matsumoto; S. Miyake

2000-01-01

411

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

SciTech Connect

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.

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

2010-01-15

412

Power Electronics in Renewable Energy Systems  

Microsoft Academic Search

The global electrical energy consumption is still rising and there is a steady demand to increase the power capacity. It is expected that it has to be doubled within 20 years. The production, distribution and use of the energy should be as technological efficient as possible and incentives to save energy at the end-user should also be set up. Deregulation

F. Blaabjerg; F. Iov; R. Teodorescu; Z. Chen

2006-01-01

413

Teachers Environmental Resource Unit: Energy and Power.  

ERIC Educational Resources Information Center

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…

Bemiss, Clair W.

414

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

415

Laser energy converted into electric power  

NASA Technical Reports Server (NTRS)

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

Shimada, K.

1973-01-01

416

Relations for a periodic array of flap-type wave energy converters  

E-print Network

This paper investigates the interaction of plane incident waves with a wave farm in the open ocean. The farm consists of a periodic array of large flap-type wave energy converters. A linear inviscid potential-flow model, already developed by the authors for a single flap in a channel, is considered. Asymptotic analysis of the wave field allows to obtain new expressions of the reflection, transmission and radiation coefficients of the system. It is shown that, unlike a line of heaving buoys, an array of flap-type converters is able to exploit resonance of the system transverse modes in order to attain high capture factor levels. Relations between the hydrodynamic coefficients are derived and applied for optimising the power output of the wave farm.

Renzi, Emiliano

2012-01-01

417

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

SciTech Connect

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.

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

2014-03-01

418

Prospect of probing dark energy using stochastic gravitational waves  

E-print Network

We study the possibility of probing dark energy behaviour using gravitational wave experiments like LISA and Advanced LIGO. Using two popular parameterizations for dark energy equation of state, we show that with current sensitivities of LISA and Advanced LIGO to detect the stochastic gravitational waves, it is possible to probe a large section of parameter space for the dark energy equation of state which is allowed by present cosmological observations.

Bikash R. Dinda; Anjan A. Sen

2015-04-15

419

Prospect of probing dark energy using stochastic gravitational waves  

E-print Network

We study the possibility of probing dark energy behaviour using gravitational wave experiments like LISA and Advanced LIGO. Using two popular parameterizations for dark energy equation of state, we show that with current sensitivities of LISA and Advanced LIGO to detect the stochastic gravitational waves, it is possible to probe a large section of parameter space for the dark energy equation of state which is allowed by present cosmological observations.

Dinda, Bikash R

2015-01-01

420

Summary of PIER-Funded Wave Energy Research  

E-print Network

, Consultant--Ocean Energy Systems. The outcomes presented herein represent an aggregation of originalCALIFORNIA ENERGY COMMISSION Summary of PIER-Funded Wave Energy Research STAFFREPORT MARCH 2008 CEC-500-2007-083 Arnold Schwarzenegger, Governor #12; #12; CALIFORNIA ENERGY COMMISSION Mike Kane

421

Power Measurement Methods for Energy Efficient Applications  

PubMed Central

Energy consumption constraints on computing systems are more important than ever. Maintenance costs for high performance systems are limiting the applicability of processing devices with large dissipation power. New solutions are needed to increase both the computation capability and the power efficiency. Moreover, energy efficient applications should balance performance vs. consumption. Therefore power data of components are important. This work presents the most remarkable alternatives to measure the power consumption of different types of computing systems, describing the advantages and limitations of available power measurement systems. Finally, a methodology is proposed to select the right power consumption measurement system taking into account precision of the measure, scalability and controllability of the acquisition system. PMID:23778191

Calandrini, Guilherme; Gardel, Alfredo; Bravo, Ignacio; Revenga, Pedro; Lázaro, José L.; Toledo-Moreo, F. Javier

2013-01-01

422

Numerical evaluation of the wave energy resource along the Atlantic European coast  

NASA Astrophysics Data System (ADS)

In the present paper a hindcast system is applied to the analysis of the Atlantic European coast as a whole with specific nestings for sites of interest in each country. The areas included in this study were: Ireland west coast, UK South Western coast, France west coast, northern Spain and Canary Islands and Portugal's continental coast. Two contemporary spectral models were used: WaveWatch III for wave generation, covering almost the entire North Atlantic basin, which outputs are then used as boundary conditions for SWAN which simulates wave transformation in coastal areas. Wind fields were taken from the ERA Interim data base. Results are validated against buoy data. These validations allowed a reformulation, when needed, of the model's configurations in order to better tune its outcomes to the real data. Using the energy transport vectors given by SWAN, the wave power is afterwards calculated and an energy resource assessment is done for a period of several years.

Guedes Soares, C.; Bento, A. Rute; Gonçalves, Marta; Silva, Dina; Martinho, Paulo

2014-10-01

423

SPS Energy Conversion Power Management Workshop  

NASA Technical Reports Server (NTRS)

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.

1980-01-01

424

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

NASA Technical Reports Server (NTRS)

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.

Wintucky, Edwin G.; Simons, Rainee N.

2014-01-01

425

Interaction of two walkers: Wave-mediated energy and force  

NASA Astrophysics Data System (ADS)

A bouncing droplet, self-propelled by its interaction with the waves it generates, forms a classical wave-particle association called a "walker." Previous works have demonstrated that the dynamics of a single walker is driven by its global surface wave field that retains information on its past trajectory. Here we investigate the energy stored in this wave field for two coupled walkers and how it conveys an interaction between them. For this purpose, we characterize experimentally the "promenade modes" where two walkers are bound and propagate together. Their possible binding distances take discrete values, and the velocity of the pair depends on their mutual binding. The mean parallel motion can be either rectilinear or oscillating. The experimental results are recovered analytically with a simple theoretical framework. A relation between the kinetic energy of the droplets and the total energy of the standing waves is established.

Borghesi, Christian; Moukhtar, Julien; Labousse, Matthieu; Eddi, Antonin; Fort, Emmanuel; Couder, Yves

2014-12-01

426

Interaction of two walkers: wave-mediated energy and force.  

PubMed

A bouncing droplet, self-propelled by its interaction with the waves it generates, forms a classical wave-particle association called a "walker." Previous works have demonstrated that the dynamics of a single walker is driven by its global surface wave field that retains information on its past trajectory. Here we investigate the energy stored in this wave field for two coupled walkers and how it conveys an interaction between them. For this purpose, we characterize experimentally the "promenade modes" where two walkers are bound and propagate together. Their possible binding distances take discrete values, and the velocity of the pair depends on their mutual binding. The mean parallel motion can be either rectilinear or oscillating. The experimental results are recovered analytically with a simple theoretical framework. A relation between the kinetic energy of the droplets and the total energy of the standing waves is established. PMID:25615197

Borghesi, Christian; Moukhtar, Julien; Labousse, Matthieu; Eddi, Antonin; Fort, Emmanuel; Couder, Yves

2014-12-01

427

Power Technologies Energy Data Book - Fourth Edition  

SciTech Connect

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.

Aabakken, J.

2006-08-01

428

Energy Decisions: Is Solar Power the Solution?  

ERIC Educational Resources Information Center

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.…

Childress, Vincent W.

2011-01-01

429

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

NASA Astrophysics Data System (ADS)

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

Yokoyama, Naoto; Takaoka, Masanori

2014-12-01

430

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

NASA Astrophysics Data System (ADS)

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.

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

2015-03-01

431

A high-power wideband traveling-wave tube using coaxial inverted helical groove slow-wave structure  

Microsoft Academic Search

The helical groove waveguide (HGW) is a potential traveling-wave tube (TWT) slow-wave structure (SWS) for use in high power applications at millimeter frequencies. It has attracted significant attention for its large size, good heat dissipation capabilities, high precision of manufacture and assembly, robust construction and low cost. Recently, we have developed a novel HGW-SWS, the coaxial inverted helical groove structure

Y. Y. Wei; B. F. Jia; Y. D. Joo; G. S. Park; H. S. Uhm; G. F. Yu; W. X. Wang; S. G. Liu

2002-01-01

432

Phase velocity and interaction impedance measurements on slow-wave structures for high-power traveling-wave tubes  

Microsoft Academic Search

In this work some results of phase velocity and interaction impedance measurements made on a ring-bar slow-wave structure for a high-power traveling-wave tube are presented and discussed. The measurements were in range from 7 to 12 GHz. The experimental results obtained were compared to an analytical cold model based on the contra-wound helix theory and to 3D simulations done with

Daniel T. Lopes; Cláudio C. Motta

2008-01-01

433

Simulation of the helical slow-wave structure of a high-power traveling-wave tube  

Microsoft Academic Search

The electrodynamic characteristics of the helical slow-wave structure of a high-power pulse traveling-wave tube operating\\u000a in the centimeter wavelength range are calculated by means of the solution of the dispersion equation and simulation. Special\\u000a attention is focused on the effect of a helix wire profile on the electrodynamic characteristics of the system. The results\\u000a of the theoretical study are compared

G. A. Azov; S. A. Khritkin

2010-01-01

434

Characteristics of Salter's cam for extracting energy from ocean waves  

Microsoft Academic Search

The performance of Salter's cam as an energy extractor from ocean waves is studied numerically on the basis of linear theory of surface waves and floating bodies. Quantities of engineering interest such as efficiency, induced motion and reaction forces are presented and discussed both for fixed and for partly constrained cam shafts.

A. E. Mynett; D. D. Serman; C. C. Mei

1979-01-01

435

Mathematical model of sea wave energy in electricity generation  

Microsoft Academic Search

This paper presents the conceptual model for pressure amplification in harnessing sea wave energy to generate electricity. It is named as AH Presto 1 which is the short form for Air-Hydraulic Pressure Storage Version 1. The idea of the concept is converting the air pressure generated from undulating sea water free surface inside the oscillating wave column (OWC) chamber adopting

Baharin Abu Bakar; Ismail Musirin; Muhammad Murtadha Othman; M. N. A Rahim

2011-01-01

436

The "Big Wave" theory for Dark Energy Blake Temple  

E-print Network

The "Big Wave" theory for Dark Energy Blake Temple (Joint work with Joel Smoller) Abstract. We to the displacement of nearby galaxies by a wave that propagated during the radiation phase of the Big Bang equations of General Relativity (GR) that contain the standard model during the radiation phase of the Big

Temple, Blake

437

Increasing Power and Energy in Amonix CPV Solar Power Plants  

Microsoft Academic Search

Large-scale concentration photovoltaic (CPV) power plants deliver the high energy production and low electricity cost that will allow photovoltaics to become a substantial portion of the electrical grid. High concentration minimizes the semiconductor material costs, while tracking delivers higher capacity factors and provides a better match to demand. In order to prove the net cost benefits, however, annual deployments must

Geoffrey S. Kinsey; Aditya Nayak; Mingguo Liu; Vahan Garboushian

2011-01-01

438

Energy Balance in Jupiter's Middle Atmosphere: Radiation and Gravity Waves  

NASA Astrophysics Data System (ADS)

The quantitative similarity of temperature fluctuations in the jovian and terrestrial middle atmospheres strengthens the case for breaking gravity waves in Jupiter's middle atmosphere.1 Breaking gravity waves directly contribute to both heating (by local deposition of wave energy) and cooling (by turbulent mixing of potential temperature). The net effect2 depends on eddy diffusion and the eddy Prandtl number, Pr, the ratio of the eddy diffusion coefficient for momentum to that for temperature. In addition, breaking waves can deposit momentum, indirectly modifying temperatures through changes in the mean circulation. The value of Pr in Jupiter's middle atmosphere is unconstrained, hampering a comparison of heating and cooling from radiation3 to that from breaking gravity waves. For Jupiter's eddy diffusion profile,4 breaking gravity waves lead to net cooling for Pr < 1.7 and net heating otherwise. For a wide range of Pr, (1 < Pr < 20, based on numerical models of breaking waves),radiation dominates over gravity waves in the lower stratosphere (10-100 mbar). However, gravity wave heating dominates over radiation in the upper stratosphere (1-10 ? bar) for Pr>10. We will discuss the evidence for jovian stratospheric gravity waves, the competing heating and cooling effects of gravity waves, and the roles of radiation and breaking gravity waves on Jupiter's stratospheric energy balance. [1] Young, L.A., R.V. Yelle, R.E. Young, A. Seiff, D.B. Kirk 2003 Gravity waves in Jupiter?s stratosphere, as measured by the Galileo ASI experiment, Icarus, submitted. [2] Strobel et al., 1985. JGR 90, 13067-13072. [3] Yelle et al., 2001. Icarus 152, 331-346. [4] Moses et al., 2002. In Jupiter: Planet, Satellites, and Magnetosphere. Cambridge U. Press. The work was supported, in part, by NASA's Planetary Atmsopheres program, through RTOP 344-33-20-03 (REY) and NEG5-9214 (RVY).

Young, L. A.; Young, R. E.; Yelle, R. V.

2003-05-01

439

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

NASA Astrophysics Data System (ADS)

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.

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

2013-04-01

440

A rotational wave energy conversion system development and validation with real ocean wave data  

Microsoft Academic Search

Recently, there has been a massive push in the research community towards green or renewable energies, specifically for electrical power generation. Fossil fuels are losing their popularity due to the associated environmental damage and hazards, and green energies are gaining momentum as significant energy resources. This paper presents a novel system and method for converting the power of open ocean

H. Bora Karayaka; Hugo Mahlke; Darek Bogucki; Mehrube Mehrubeoglu

2011-01-01

441

Coal and nuclear power: Illinois' energy future  

SciTech Connect

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.

Not Available

1982-01-01

442

Space solar power - An energy alternative  

NASA Technical Reports Server (NTRS)

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.

Johnson, R. W.

1978-01-01

443

Energy storage and generation from thermopower waves  

E-print Network

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 ...

Abrahamson, Joel T. (Joel Theodore)

2012-01-01

444

Saving Energy Through Advanced Power Strips (Poster)  

SciTech Connect

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.

Christensen, D.

2013-10-01

445

Internal wave energy radiated from a turbulent mixed layer  

SciTech Connect

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.

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

2014-09-15

446

On the configuration of arrays of floating wave energy converters   

E-print Network

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 ...

Child, Benjamin Frederick Martin

2011-11-22

447

Internal wave energy radiated from a turbulent mixed layer  

NASA Astrophysics Data System (ADS)

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.

Munroe, James R.; Sutherland, Bruce R.

2014-09-01

448

Optimal Power Allocation for Renewable Energy Source  

E-print Network

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

Sinha, Abhinav

2011-01-01

449

Laser-Energy Transfer and Enhancement of Plasma Waves and Electron Beams by Interfering High-Intensity Laser Pulses  

E-print Network

pulses were crossed in a plasma of density 4 1019 cm3 . Energy was observed to be transferred from the higher-power to the lower-power pulse, increasing the amplitude of the plasma wave propagating of high-intensity laser pulses in plasma are of much current interest because of their relevance

Umstadter, Donald

450

Wave energy research, development and demonstration at Oregon State University  

Microsoft Academic Search

This paper presents the wave energy research, development and demonstration (RD&D) efforts at Oregon State University (OSU), including the activities of the Northwest National Marine Renewable Energy Center (NNMREC) headquartered at OSU. The NNMREC facilities and research thrusts are described, and a full-scale mobile ocean test berth (MOTB) concept is detailed. In addition, a high-precision wave tank testing system established

Annette von Jouanne; Ted Brekken

2011-01-01

451

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

E-print Network

Near-Millimeter Wave Issues for a Space Power Grid Narayanan Komerath, Vigneshwar Venkat, Jason, seeking the performance figures needed for a self-sustaining system and to open up Space Solar Power in 15 of direct solar conversion to DC and to beamed power would satisfy the needed efficiencies but requires

452

Continuous-wave high-power rotational Raman generation in molecular deuterium  

E-print Network

Continuous-wave high-power rotational Raman generation in molecular deuterium J. T. Green, D. E the generation of more than 300 mW of rotational Stokes output power in a CW Raman laser. The generation properties. Both rotational and vibrational Stokes sideband generation has been re- ported with output powers

Yavuz, Deniz

453

The wells air turbine for wave energy conversion  

Microsoft Academic Search

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

S. Raghunathan

1995-01-01

454

Neural rotational speed control for wave energy converters  

Microsoft Academic Search

Among the benefits arising from an increasing use of renewable energy are: enhanced security of energy supply, stimulation of economic growth, job creation and protection of the environment. In this context, this study analyses the performance of an oscillating water column device for wave energy conversion in function of the stalling behaviour in Wells turbines, one of the most widely

M. Amundarain; M. Alberdi; A. J. Garrido; I. Garrido

2011-01-01

455

Breezy Power: From Wind to Energy  

ERIC Educational Resources Information Center

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…

Claymier, Bob

2009-01-01

456

Fluid Power Systems. Energy Technology Series.  

ERIC Educational Resources Information Center

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…

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

457

Channels of energy for the linear radial wave equation  

E-print Network

Exterior channel of energy estimates for the radial wave equation were first considered in three dimensions by Duyckaerts, the first author, and Merle, and recently for the 5-dimensional case by the first, second, and fourth authors. In this paper we find the general form of the channel of energy estimate in all odd dimensions for the radial free wave equation. This will be used in a companion paper to establish soliton resolution for equivariant wave maps in 3 dimensions exterior to the ball B(0,1), and in all equivariance classes.

Carlos Kenig; Andrew Lawrie; Baoping Liu; Wilhelm Schlag

2014-09-12

458

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

SciTech Connect

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.

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

2014-06-23

459

Assessment of boundary-element method for modelling a free-floating sloped wave energy device. Part 1: Numerical modelling  

Microsoft Academic Search

The boundary-element method has been widely used as a design tool in the offshore and ship building industry for more than 30 years. Its application to wave energy conversion is, however, more recent. This paper deals with the numerical modelling of a free-floating sloped wave energy device. The power take-off mechanism of the device consists of an immersed tube with

Grégory S. Payne; Jamie R. M. Taylor; Tom Bruce; Penny Parkin

2008-01-01

460

Energy Servers Deliver Clean, Affordable Power  

NASA Technical Reports Server (NTRS)

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.

2010-01-01

461

Equilibrium shoreline response of a high wave energy beach  

NASA Astrophysics Data System (ADS)

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.

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

2011-04-01

462

Equilibrium shoreline response of a high wave energy beach  

USGS Publications Warehouse

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.

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

2011-01-01

463

A high-power traveling wave ultrasonic motor  

Microsoft Academic Search

In the present work, a traveling wave ultrasonic motor (TWUSM) is proposed. It is composed of an annular-shaped stator and two cone-shaped rotors that are pressed in contact to the borders of the inner surface of the stator. A rotating traveling wave has been generated in the stator by using as vibration generators two bolted Langevin transducers (BLT) opportunely shifted

Antonio Iula; Massimo Pappalardo

2006-01-01

464

Energy storage options for space power  

NASA Astrophysics Data System (ADS)

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

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

465

Energy storage options for space power  

SciTech Connect

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.

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

1985-01-01

466

Evaluation of an energy-propagation wave refraction model  

NASA Astrophysics Data System (ADS)

A simple wave refraction model, based on the conservation of wave energy entering and leaving grid squares defined by an areal array of equally spaced depth points, has been tested on a number of idealized bathymetries and against two field data sets. The model allows waves to cross by treating the directionality of the wave field in terms of discrete energy bins 10° apart. Algorithms for predicting the extent of partial breaking ( DALLY, DEAN and DALRYMPLE, 1985 ; Journal of Geophysical Research, 90, 11917-11927) and for bottom friction over a movable bed ( GRANT and MADSEN, 1982 ; Journal of Geophysical Research, 87, 469-481) were initially incorporated in the model but, for operational reasons, were replaced by a fixed 'wave height to water depth' limit of 0.5 and by a single friction factor specified by the user. For a simple linear shoreline, close correspondence was found between the model and Snell's law for offshore directions up to 45° wave height differences are <5% while for direction the differences rise to <10% in 2 m water depth. Over a linear bank differences in wave angle between opposite sides can exceed 20% when uni-directional waves are used, due to the algorithm being irreversible; when waves with a directional spread are used the differences drop to <10%. The model is able to predict well the wave heights measured at a number of locations in Haringvliet Estuary, Holland after the friction factor was tuned to 0.04, although the higher-than-predicted wave heights further into the estuary suggests that energy input from the wind is significant and so the friction factor of 0.04 is probably an underestimate. The model also shows reasonable directional predictive ability when tested against data from Pt Sapin, Canada. Wave heights at this location are also in good agreement but suggest a friction factor nearer 0.1. The model performed well when compared with field data from Holland and Canada but was found to have a number of limitations when run over simple "control' bathymetries. These were (a) the irreversibility of the algorithm which results in different refraction rates over opposite sides of a linear bank, (b) edge influences which propagate into the middle of the domain and (c) the steady energy loss which occurs as energy leaks into directions beyond the range of the model. However, if the model is used with care, avoiding regions where diffraction and reflection may be important and selecting a friction factor appropriate to the area, it can be a useful tool for predicting wave heights and directions.

Vincent, C. E.; Carrie, A.

1988-03-01

467

Hurricane Wave Power Extremes Along the U.S. Atlantic and Gulf Coasts  

Microsoft Academic Search

Extremes in wave power generated by tropical cyclones (TCs) will have an increasingly greater coastal impact as mean sea level rises. The Gulf 98th percentile (3 m) deep-water significant wave height, HS, measured at four open ocean NOAA buoys along the U.S. Atlantic coast and three Gulf buoys identifies extreme TC-generated wave events during the June-November hurricane season. Since 1978,

P. D. Bromirski; J. P. Kossin

2007-01-01

468

Fabrication of Bulk Ceramics by High-Power Millimeter-Wave Radiation  

Microsoft Academic Search

High-power 28 GHz millimeter-wave radiation was applied to the fabrication of bulk AlN, Si3N4 and Al2O3. Millimeter-wave radiation enables the rapid sintering of these ceramics at a temperature from 50°C to 300°C lower than that of the conventional method. The rapid sintering is attributed to the enhancement of atomic migration due to the ``nonthermal effect'' of the millimeter wave. It

Yukio Makino; Toshiyuki Ueno; Takeshi Matsumoto; Shoji Miyake

2001-01-01

469

High power, continuous-wave ytterbium-doped fiber laser tunable from 976 to 1120 nm  

E-print Network

High power, continuous-wave ytterbium-doped fiber laser tunable from 976 to 1120 nm Romain Royon,1 Abstract: We report on a linearly-polarized, continuous-wave Ytterbium- doped fiber laser continuously to more than 1 nm at all wavelengths ©2013 Optical Society of America OCIS codes: (140.3510) Lasers, fiber

Paris-Sud XI, Université de

470

Ionospheric Heating by Radio Waves: Predictions for Arecibo and the Satellite Power Station  

Microsoft Academic Search

The effect of resistive heating by radio waves on ionospheric temperatures, electron densities, and airglow emissions is examined by using numerical ionospheric structure and heat balance codes. Two cases are studied: (1) a 3-GHz, 10-GW microwave beam from a proposed satellite power station and (2) IMW and 3-MW beams of 15-MHz radio waves launched by the Arecibo antenna. By intent,

F. W. Perkins; R. G. Roble

1978-01-01

471

Low frequency energy scavenging using sub-wave length scale acousto-elastic metamaterial  

NASA Astrophysics Data System (ADS)

This letter presents the possibility of energy scavenging (ES) utilizing the physics of acousto-elastic metamaterial (AEMM) at low frequencies (<˜3KHz). It is proposed to use the AEMM in a dual mode (Acoustic Filter and Energy Harvester), simultaneously. AEMM's are typically reported for filtering acoustic waves by trapping or guiding the acoustic energy, whereas this letter shows that the dynamic energy trapped inside the soft constituent (matrix) of metamaterials can be significantly harvested by strategically embedding piezoelectric wafers in the matrix. With unit cell AEMM model, we experimentally asserted that at lower acoustic frequencies (< ˜3 KHz), maximum power in the micro Watts (˜35µW) range can be generated, whereas, recently reported phononic crystal based metamaterials harvested only nano Watt (˜30nW) power against 10K? resistive load. Efficient energy scavengers at low acoustic frequencies are almost absent due to large required size relevant to the acoustic wavelength. Here we report sub wave length scale energy scavengers utilizing the coupled physics of local, structural and matrix resonances. Upon validation of the argument through analytical, numerical and experimental studies, a multi-frequency energy scavenger (ES) with multi-cell model is designed with varying geometrical properties capable of scavenging energy (power output from ˜10µW - ˜90µW) between 0.2 KHz and 1.5 KHz acoustic frequencies.

Ahmed, Riaz U.; Banerjee, Sourav

2014-11-01

472

Power management for energy harvesting wireless sensors  

NASA Astrophysics Data System (ADS)

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.

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

2005-05-01

473

Enhanced frequency agility of high-power relativistic backward wave oscillators  

Microsoft Academic Search

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

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

1996-01-01

474

A novel overmoded slow-wave high-power microwave (HPM) Generator  

Microsoft Academic Search

We present the design and experimental results of a novel overmoded slow-wave high-power microwave (HPM) generator that is featured by its compactness, low-operation magnetic field, and potentially high power and high efficiency. The device includes two slow-wave structure (SWS) sections, a resonant cavity, and a tapered waveguide. The resonant cavity was well designed and was used to achieve the axial

Jun Zhang; Hui-Huang Zhong; Ling Luo

2004-01-01

475

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

476

Efficiency enhancement of high power vacuum BWO's using nonuniform slow wave structures  

Microsoft Academic Search

The Sinus-6, a high-power relativistic repetitively-pulsed electron beam accelerator, is used to drive various slow wave structures in a BWO configuration in vacuum. Peak output power of about 550 MW at 9.45 GHz was radiated in an 8-ns pulse. We describe experiments which study the relative efficiencies of microwave generation from a two-stage nonuniform amplitude slow wave structure and its

Larald D. Moreland; E. Schamiloglu; W. Lemke; S. D. Korovin; V. V. Rostov; A. M. Roitman; K. J. Hendricks; T. A. Spencer

1994-01-01

477

Dam-Atoll for concentration and conversion of ocean wave energy  

Microsoft Academic Search

A simple wave energy conversion device has recently been patented by Lockheed. The Dam-Atoll concept uses passive structure and the principle of wave refraction as the primary elements to convert wave energy into usable energy. Each unit can provide 1 to 2 MW in an area of adequate wave energy resource. Plans have been formulated for additional development work which

T. P. Higgins; C. P. Sherburne

1981-01-01

478

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

DOEpatents

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.

Koplow, Jeffrey P. (San Ramon, CA)

2012-07-03

479

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

SciTech Connect

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.

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

2011-11-15

480

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

Microsoft Academic Search

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

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

1995-01-01

481

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

NASA Astrophysics Data System (ADS)

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

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

2011-12-01

482

Optimum control of a floating wave-energy converter with restricted amplitude  

SciTech Connect

In this paper, the use of optimal control techniques for improving the energy absorption by a wave-energy converter (WEC) is investigated. A mathematical model is developed for a floating body, which is exposed to an irregular incident wave, and is moving relative to a fixed reference. This model includes a control force from the power take-off and control machinery, and a friction force which restricts the oscillation amplitude. This force models end-stop devices, which are necessary to protect the machinery. An optimal control strategy is determined, based on variations of a Lagrange functional. This gives a set of adjoint equations in addition to the state equations, as a necessary condition for optimum. An algorithm is given for solving the problem numerically by iteration, based on a gradient method. It is shown that the optimal motion in a sinusoidal wave is not sinusoidal when the excursion is constrained. Instead, the motion should be stopped in certain intervals. In irregular waves the constrained solution is close to the unconstrained solution when the excursion is small. Moreover, the timings of the extrema and of the zero crossings agree fairly well. When the excursion is constrained, the mean output power is reduced compared to the unconstrained case, but the ratio between the output energy and the total energy passing through the machinery is increased. This means that the conversion efficiency of the machinery is less critical.

Eidsmoen, H. [Norwegian Inst. of Tech., Trondheim (Norway). Div. of Physics

1996-05-01

483

Optimum control of a floating wave energy converter with restricted amplitude  

SciTech Connect

In this paper the use of optimal control techniques for improving the energy absorption by a wave energy converter (WEC) is investigated. A mathematical model is developed for a floating body, which is exposed to an irregular incident wave, and is moving relative to a fixed reference. This model includes a control force form the power take-off and control machinery, and a friction force which restricts the amplitude. This force models end-stop devices, which are necessary to protect the machinery. An optimal control strategy is determined, based on variations of a Lagrange functional. This gives a set of adjoint equations in addition to the state equations, as a necessary condition for optimum. An algorithm is given for solving the problem numerically by iteration, based on a gradient method. It is shown that the optimal motion in a sinusoidal wave is not sinusoidal when the excursion is constrained. Instead the motion should be stopped in certain intervals. In irregular waves the constrained solution is close to the unconstrained solution when the excursion is small. Moreover, the timings of the extrema and of the zero crossings agree fairly well. When the excursion is constrained the mean output power is reduced compared to the unconstrained case, but the ratio between the output energy and the total energy passing through the machine is increased. This means that the conversion efficiency of the machinery is less critical.

Eidsmoen, H. [Norwegian Inst. of Tech., Trondheim (Norway). Div. of Physics

1995-12-31

484

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

NASA Technical Reports Server (NTRS)

[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.

2007-01-01

485

Damping Pressure Pulsations in a Wave-Powered Desalination System  

E-print Network

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 ...

Padhye, Nikhil

486

Nonequilibrium Statistics of a Reduced Model for Energy Transfer in Waves  

E-print Network

. For example, ocean surface waves are thought to be initiated by the wind at small (capillary) scales;2 DEVILLE ET AL. For dispersive wave systems, such as surface ocean waves and internal waves is through wave "collisions") for the evolution of the Fourier spectrum. Sometimes special power law

Milewski, Paul

487

Suppression of spurious modes in high power travelling wave tubes  

Microsoft Academic Search

The main task of this work was to establish suitable means to suppress band edge oscillations in broad band coupled-cavity TWT's. The electric field flux lines in the slow wave structure have been calculated by means of conformal mapping. In the operating range, only transversal waves are existent, whereas at the upper cut-off frequency also E-modes are stimulated, esp. in

E. Glass

1982-01-01

488

Efficiency enhancement techniques for RF and millimeter wave power amplifiers  

E-print Network

Power amplifiers are the circuit blocks in wireless transceivers that require the largest power budget because of their relatively low efficiencies. RF designers cannot depend solely on the development better semiconductor ...

Ogunnika, Olumuyiwa Temitope, 1978-

2012-01-01

489

Energy saving potential of office equipment power management  

Microsoft Academic Search

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

Kaoru Kawamoto; Yoshiyuki Shimoda; Minoru Mizuno