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1

Wave energy power station  

SciTech Connect

A wave energy power station comprises two water-filled chambers in communication at the bottom, wherein a first chamber is in communication with the sea at the upper end thereof and the second chamber is defined by one or more walls which project above the surface of the sea, such that pressure variations in the sea owing to the waves will set the water in an oscillating movement between the two chambers, and energy being tapped from the oscillating system, for example, by allowing the water in the chamber which is not in communication with the sea to overflow periodically into a reservoir, from which it is led back to the sea through a turbine, or by utilizing the water column in the second chamber for drawing in and compressing air which drives an air turbine. A water-filled tank is permanently installed on the sea bed or floating in the sea, and has a bottom and one or more walls, at least one wall or a portion of one wall being terminated at the upper edge thereof below the surface of the sea , the submerged upper edge and a partition wall which can be fixed or movable up and down in the water in the tank together defining the upper end of the chamber which communicates with the sea, the partition wall also, alone or together with one or more of the tank walls which project up above the surface of the water , defining the second chamber end which is not in communication with the sea, there being provided in the case of a fixed partition wall an adjacent tank wall section which is adapted for movement toward and away from the partition wall at the end of the second chamber for regulating the cross-sectional surface at that chamber end.

Ambli, N.

1982-07-27

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

Power conversion mechanisms for wave energy  

Microsoft Academic Search

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

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

2002-01-01

4

Expansion of Positive Energy Coulomb Wave Functions in Powers of the Energy  

Microsoft Academic Search

The non-relativistic wave function (in spherical polar coordinates) for a charged particle in a Coulomb field is expressed in a form suitable for problems in which the particle has a small positive energy. This formulation amounts to expanding the radial part of the wave function in powers of the energy E and is achieved by simple algebraic manipulation of power

J. G. Beckerley

1945-01-01

5

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

6

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

7

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

8

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

9

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

10

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

11

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

Microsoft Academic Search

Power and energy measurments 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

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

1981-01-01

12

Power electronics as grid interface for actively controlled wave energy converters  

Microsoft Academic Search

Off the coasts of Europe, the potential for power generation from offshore renewable energy is huge and the technology for offshore wind power is already becoming available. Achievement of a cost-effective technology is the main concern for commercial development of wave energy converters (WEC). It is widely recognized that some kind of active control of the primary conversion is needed

Marta Molinas; Ottar Skjervheim; Pål Andreasen; Tore Undeland; Jørgen Hals; Torgeir Moan; B. Sorby

2007-01-01

13

Applications of high-power millimeter waves in fusion energy research  

Microsoft Academic Search

High-power millimeter wave sources are a key enabling technology in fusion energy research. The present state of the art of application of these sources to the areas of heating, current generation, and scattering for diagnostic purposes in fusion plasmas is reviewed. The extrapolation of these applications to future devices and the requirements which they place on sources and transmission lines

Timothy C. Luce

2002-01-01

14

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

15

An inquiry into the feasibility of using ocean surface wave energy to power an oceanographic data collection buoy. Final report  

Microsoft Academic Search

A brief history of attempts to use ocean surface wave energy is presented and applicable wave theory is reviewed. Six distinct modes of interaction between a wave and a buoy are defined. These are evaluated by deriving expressions for the maximum power realizable from each and by considering how the use of each would affect buoy functioning. Those modes involving

1969-01-01

16

Hydrodynamics of ocean wave-energy utilization  

Microsoft Academic Search

This book presents papers on wave energy converters. Topics considered include hydrodynamics, resonance, air turbines, buoys, physical and mathematical modeling, nonlinear damping, China's research on wave power, wave climate, site selection, wave forces, ship propulsion, wave energy absorption, phase control, optimal control, oscillating water columns, air flow, pneumatics, wave propagation, the survival of surface-piercing wave energy devices in extreme waves,

D. V. Evans; A. F. de O. Falcao

1985-01-01

17

Experiments to Improve Power Conversion Parameters in a Traveling Wave Direct Energy Converter Simulator  

Microsoft Academic Search

An experimental study of direct power conversion for D-³He fusion is presented. In a small-scale simulator of direct energy converter, which is based on a principle of deceleration of 14.7MeV protons by traveling wave field, a new structure of an external transmission circuit in experiment is proposed for the purpose of enhancement of deceleration electrode voltages. A prototype circuit was

Hiromasa Takeno; Yuusuke Kiriyama; Yasuyoshi Yasaka

2005-01-01

18

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

19

Wave-powered motor  

SciTech Connect

A dome-shaped atoll structure having a central aperture at its apex is secured to a station-keeping structure positioned on the ocean bottom. The atoll structure moveable through a range of vertical positions relative to the ocean bottom. Sea waves impinging on the atoll structure are refracted as they crest and break, thereby producing spiralling pulses of water that converge toward the central aperture. The central aperture provides entry into a vertical standpipe for the pulses of water, which impart angular momentum to water already present in the standpipe. A turbine attached to a shaft in the standpipe converts the rotational energy of the water in the standpipe to rotational energy of the shaft, which is coupled to an electrical generator. The electric power output of the generator is measured for various vertical positions through which the atoll member is moved, so that a position of optimum power output can be determined for any given combination of sea state and/or tidal conditions.

Weyers, P.F.

1982-04-27

20

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

21

Ocean wave energy device  

SciTech Connect

This patent describes an ocean wave energy device of a type including a buoy which reciprocates in a substantially vertical direction in response to successive waves of variable frequency passing therebeneath, the buoy being supported upon a substantially vertically oriented shaft and a power take off means including a shaft driven by movement of the vertical shaft. The improvement described consists of: wave frequency detector means for detecting the instantaneous frequency of a wave passing the detector and which will thereafter pass the buoy by monitoring the contour of each wave as such wave passes such wave frequency detector means and measuring the time interval between the crest and the following trough and between the trough and following crest of each such wave and means for imposing an artificial resonance to the buoy whereby the buoy resonance may be substantially conformed to the frequency of the wave at the time at the buoy, the artificial resonance imposing means including brake means for halting vertical movement of the buoy at substantially the uppermost and substantially the lowermost limits of vertical travel of the buoy.

LaStella, J.P.; Tornabene, M.G.

1986-07-15

22

Hydroelectric power from ocean waves  

NASA Astrophysics Data System (ADS)

This paper describes a system which converts the variable energy of ocean waves into a steady supply of energy in a conventional form. The system consists of a set of floats and Persian wheels located off-shore and a storage reservoir on the shore. The floats oscillate vertically as the waves pass below them and turn their respective Persian wheels which lift sea water to a height and deliver to the reservoir through an interconnecting pipeline. The head of water in the reservoir operates a hydraulic turbine which in turn works a generator to supply electricity. Due to the recurrent wave action, water is maintained at the optimum level in the reservoir to ensure continuous power supply.

Raghavendran, K.

1981-02-01

23

Ocean wave energy conversion  

NASA Astrophysics Data System (ADS)

The book provides a review of ocean wave mechanics and an introduction to wave energy conversion. Physical and mathematical descriptions are given of the nine generic wave energy conversion techniques along with their uses and performance characteristics. A number of electro-mechanical energy conversion techniques are described. Attention is also given to the possible environmental effects associated with wave energy conversion.

McCormick, M. E.

24

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

25

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

26

Wave powered buoy generator  

SciTech Connect

The wave powered buoy generator includes a hollow buoy which has inner and outer surfaces. The buoy is preferably spherical in shape. One or more windings are mounted to the buoy parallel to its surfaces with each winding having a pair of ends. A magnetized device which, is preferably a ball, is located within the buoy for rolling back and forth therein. A device is connected to the ends of the windings for rectifying current flow therefrom. With this arrangement the buoy can be moored in a body of water, and, when there is water motion, the flux lines of the magnetized roller device cut the one or more windings so as to cause electrical current flow to be provided through the rectifying device.

Rowe, R.A.

1985-01-08

27

Wave powered buoy generator  

SciTech Connect

The wave powered buoy generator includes a hollow buoy which has inner and outer surfaces. The buoy is preferably spherical in shape. One or more windings are mounted to the buoy parallel to its surfaces with each winding havng a pair of ends. A magnetized device which, is preferably a ball, is located within the buoy for rolling back and forth therein. A device is connected to the ends of the windings for rectifying current flow therefrom. With this arrangement the buoy can be moored in a body of water, and, when there is water motion, the flux lines of the magnetized roller device cut the one or more windings so as to cause electrical current flow to be provided through the rectifying device.

Rowe, R.A.

1982-12-02

28

Experimental Studies of Wave Hydraulic Power Units  

Microsoft Academic Search

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

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

2003-01-01

29

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

2011-07-27

30

Blast wave energy diagnostic  

NASA Astrophysics Data System (ADS)

The distance radiation waves that supersonically propagate in optically thick, diffusive media are energy sensitive. A blast wave can form in a material when the initially diffusive, supersonic radiation wave becomes transonic. Under specific conditions, the blast wave is visible with radiography as a density perturbation. [Peterson et al., Phys. Plasmas 13, 056901 (2006)] showed that the time-integrated drive energy can be measured using blast wave positions with uncertainties less than 10% at the Z Facility. In some cases, direct measurements of energy loss through diagnostic holes are not possible with bolometric and x-ray radiometric diagnostics. Thus, radiography of high compression blast waves can serve as a complementary technique that provides time-integrated energy loss through apertures. In this paper, we use blast waves to characterize the energy emerging through a 2.4 mm aperture and show experimental results in comparison to simulations.

Tierney, Thomas E.; Tierney, Heidi E.; Idzorek, George C.; Watt, Robert G.; Peterson, Robert R.; Peterson, Darrell L.; Fryer, Christopher L.; Lopez, Mike R.; Jones, Michael C.; Sinars, Daniel; Rochau, Gregory A.; Bailey, James E.

2008-10-01

31

Hydroelectric power from ocean waves  

Microsoft Academic Search

This paper describes a system which converts the variable energy of ocean waves into a steady supply of energy in a conventional form. The system consists of a set of floats and Persian wheels located off-shore and a storage reservoir on the shore. The floats oscillate vertically as the waves pass below them and turn their respective Persian wheels which

K. Raghavendran

1981-01-01

32

Wave-operated power plant  

Microsoft Academic Search

This wave-operated power plant comprises a perforated caisson breakwater in which propellers, or turbines, are mounted in the perforations or openings and drives hydraulic pumps connected thereto, which in turn drives a hydraulic motor coupled to an electric generator. One-way flap valves are mounted in the openings. Some of said flap valves allow the rushing waves to enter the caisson,

Ghesquiere

1980-01-01

33

The U.S. Army program for improving near-millimeter wave power and energy standards  

Microsoft Academic Search

The efforts of the U.S. Army Metrology and Calibration Center to obtain about a five-fold improvement in the accuracy of power and energy standards for the far infrared spectral region, 0.1-1.2 mm, are described. Total uncertainties for most FIR calibrations are placed at + or - 25% or worse, with no traceability to national standards. The present goal is to

M. L. Fecteau

1981-01-01

34

Wave power absorption: Experiments in open sea and simulation  

Microsoft Academic Search

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

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

2007-01-01

35

Wave-operated power plant  

SciTech Connect

This wave-operated power plant comprises a perforated caisson breakwater in which propellers, or turbines, are mounted in the perforations or openings and drives hydraulic pumps connected thereto, which in turn drives a hydraulic motor coupled to an electric generator. One-way flap valves are mounted in the openings. Some of said flap valves allow the rushing waves to enter the caisson, while the other flap valves allow the water to flow out of the caisson.

Ghesquiere, H.

1980-08-12

36

Ocean Wave Energy Harvesting Devices.  

National Technical Information Service (NTIS)

Development of a mechanically sound buoy design. which generated 10W average power in Beaufort Sea State I. and showed potential for up to 20W in Sea State 4. Development of a wave energy harvesting buoy capable of generating 2W in Sea State I. and with p...

E. F. Childress J. T. Cheung

2008-01-01

37

HIGH RESOLUTION WAVE TANK TESTING OF SCALED WAVE ENERGY DEVICES  

Microsoft Academic Search

In many industries, such as the wave energy industry, the importance of accurate physical model testing in the development process to full scale devices cannot be overemphasized. This paper presents a new, high-precision wave tank testing system and process designed and implemented by Columbia Power Technologies (CPT) and Oregon State University (OSU). The system's high level of functionality was demonstrated

Ken Rhinefrank; Al Schacher; Joe Prudell; Chad Stillinger; David Naviaux; Ted Brekken; Annette von Jouanne; David Newborn; Solomon Yim; Dan Cox

2010-01-01

38

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

39

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

40

Study of a hybrid offshore wind and seashore wave farm connected to a large power grid through a flywheel energy storage system  

Microsoft Academic Search

This paper presents the analyzed results of an integration of an offshore wind farm (OWF) and a seashore wave farm (WAF) connected to an onshore large power grid using a flywheel energy storage system (FESS) to simultaneously achieve power-fluctuation mitigation and dynamic-stability enhancement. The performance of the studied OWF is simulated by an equivalent aggregated 80-MW doubly-fed induction generator (DFIG)

Li Wang; Shen-Ron Jan; Chao-Nan Li; Hao-Wen Li; Yi-Hsuan Huang; Yi-Ting Chen; Sheng-Wen Wang

2011-01-01

41

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

42

Alpha power channeling with two waves.  

National Technical Information Service (NTIS)

The complete channeling of energy from alpha particles is likely to be realized only through the excitation of a variety of waves, rather than by one wave alone. While one wave constrains more firmly the direction of the energy transfer, the necessary wav...

N. J. Fisch M. C. Herrmann

1995-01-01

43

Wave energy apparatus  

SciTech Connect

Wave energy apparatus comprises a hollow buoy for floating in water. The buoy has a turbine which rotates in response to air flow into and out of the buoy through a nozzle. The turbine is designed to rotate in the same direction regardless of the axial direction of air flow. The air flow is caused by the change of level of water within the buoy in response to wave motion. To enable rocking motion to be accommodated as well as vertical motion, the interior of the buoy is divided into a plurality of conduits, by means of partitions, the conduits directing air to different portions of the turbine. The conduits preferably have lateral openings and may be defined in part by upwardly inclined portions of an inertial body. In an alternative embodiment the buoy has a closed bottom and liquid in the buoy is acted on by a centrally disposed air spring.

Wells, A.A.

1983-05-17

44

Wave energy desalinization  

SciTech Connect

A device for producing fresh water from salt sea water by utilizing the hydrodynamic energy of waves, comprising a buoyant platform; means for mooring the platform; a pump connected to the mooring means; a reservoir for pressurized sea water; a desalination system for extracting fresh water from the sea water; hydraulic flow control means for causing the pump to pump sea water into the sea water reservoir, as motion of the buoyant platform is produced due to the passing of waves beneath it; measuring means for measuring parameters of the sea adjacent the buoyant platform; and a control device connected to control the pressure in the sea water reservoir and the flow of sea water from the reservoir through the desalination system in response to the parameters of the sea.

Hopfe, H.H.

1982-06-22

45

Wave energy potential in Galicia (NW Spain)  

Microsoft Academic Search

Wave power presents significant advantages with regard to other CO2-free energy sources, among which the predictability, high load factor and low visual and environmental impact stand out. Galicia, facing the Atlantic on the north-western corner of the Iberian Peninsula, is subjected to a very harsh wave climate; in this work its potential for energy production is assessed based on three-hourly

G. Iglesias; M. López; R. Carballo; A. Castro; J. A. Fraguela; P. Frigaard

2009-01-01

46

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

47

The global morphology of wave Poynting flux: powering the aurora.  

PubMed

Large-scale, electric currents flowing along magnetic field lines into the polar regions of Earth are thought to be the main contributors of the energy that powers the ionospheric aurora. However, we have found evidence for global contributions from electromagnetic waves (Alfvén waves). Data that were collected from the Polar spacecraft over the course of 1 year show that the flow of wave electromagnetic energy at altitudes of 25,000 to 38,000 kilometers delineates the statistical auroral oval. The Poynting flux of individual events distributed along the auroral oval was larger than 5 ergs per square centimeter per second, which is sufficient to power auroral acceleration processes. This evidence suggests that in addition to magnetic field-aligned currents, the dayside and nightside aurora is globally powered by the energy flow of these high-altitude Alfvén waves. PMID:12532014

Keiling, A; Wygant, J R; Cattell, C A; Mozer, F S; Russell, C T

2003-01-17

48

Wave energy supplying for wireless sensor nodes  

Microsoft Academic Search

With the purpose of solving the continuous supply of energy of wireless sensor network in the water environment, wave power is utilized for wireless sensor nodes. Based on mechanical movement principle and electromagnetic induction. This paper has designed two mini generator, namely gear device and pulley device. The electrical energy which mini generator generates puts aside the battery via AC-DC

Jin Bo; Jiang Zhong-qiu; Yan Shu

2010-01-01

49

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

50

Wave energy and intertidal productivity  

PubMed Central

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

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

1987-01-01

51

Tide following wave power machine  

Microsoft Academic Search

At least two spaced piers are constructed on a suitable tidal beach extending from the shore into the water a predetermined distance to meet the first breaking waves at low tide. A carriage is movably supported on the piers on an inclined path, the carriage having a frame supporting a pair of spaced sprocket wheels on each end over which

1982-01-01

52

Boat powered by sea waves  

SciTech Connect

A boat having an external float pivotally fixed to the boat. Through linkage, the motion of the float relative to the boat resulting from wave motion drives a dual cylinder pump. The pump admits water from the body of water in which the boat is suspended and pressurizes that water for direction aft as a means for propulsion.

Gargos, G.

1984-11-06

53

High-power millimeter-wave tubes  

Microsoft Academic Search

8-mm and 3-mm high-power tubes have been developed. Two 8-mm-wavelength systems are examined: (1) a medium-power (tens of kilowatts) TWT (traveling wave tube) chain using PPM focusing and a low-gain 'see-through' final stage and (2) a three-beam 50-W CW (continuous-wave) klystron. In addition, a 2-kW CW TWT was developed for industrial heating. For higher powers an orotron-TWT (3-MW peak, 3-kW

M. I. Lopin; B. A. Belyavsky; K. G. Simonov; V. A. Cherepenin; A. D. Zakurdayev; B. S. Grishin; A. A. Negirev; A. S. Pobedonostev

1993-01-01

54

Current and Novel Electrical Generator Technology for Wave Energy Converters  

Microsoft Academic Search

Wave energy is currently an untapped resource, but has the potential to make a significant contribution to the energy mix. In order to use conventional electrical generators mechanical interfaces are used, such as hydraulic systems and air-turbines. With the electrical generator these interfaces are known as the electrical power take-off and the type used depends upon the wave energy device.

M. A. Mueller; Henk Polinder; Nick Baker

2007-01-01

55

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

56

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

57

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

58

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

59

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

60

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

61

A consistent derivation of the wave-energy equation from basic hydrodynamic principles  

Microsoft Academic Search

Based on a decomposition of the velocity into mean flow, turbulent and wave components, momentum and hereafter a wave-energy equation is derived. It contains a turbulent energy dissipation term which is closed by applying a wave-related mixing length model and linear wave theory solutions. This closure produces a non-linear turbulent wave-energy dissipation including the wave energy in a 5\\/2 power

Andreas Malcherek

2003-01-01

62

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

63

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

64

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

65

Ocean Wave Energy Harvesting Devices.  

National Technical Information Service (NTIS)

Development of an ocean wave energy-harvesting device that can be used as a renewable energy source for ocean monitoring systems. The core technology is a mass-spring based high efficiency, low frequency linear generator that was integrated to a spar buoy...

I. E. Childress J. T. Cheung

2007-01-01

66

Bristol cylinder wave energy device; consultancy to review of wave energy.  

National Technical Information Service (NTIS)

A review of possible power conversion systems for the Bristol Cylinder wave energy device is reported and justification for the preferred option is given. It is shown that, for demonstration and early production units, off-the-shelf equipment could be use...

1992-01-01

67

Quantifying the Benefits of Combining Offshore Wind and Wave Energy  

NASA Astrophysics Data System (ADS)

For many locations the offshore wind resource and the wave energy resource are collocated, which suggests a natural synergy if both technologies are combined into one offshore marine renewable energy plant. Initial meteorological assessments of the western coast of the United States suggest only a weak correlation in power levels of wind and wave energy at any given hour associated with the large ocean basin wave dynamics and storm systems of the North Pacific. This finding indicates that combining the two power sources could reduce the variability in electric power output from a combined wind and wave offshore plant. A combined plant is modeled with offshore wind turbines and Pelamis wave energy converters with wind and wave data from meteorological buoys operated by the US National Buoy Data Center off the coast of California, Oregon, and Washington. This study will present results of quantifying the benefits of combining wind and wave energy for the electrical power system to facilitate increased renewable energy penetration to support reductions in greenhouse gas emissions, and air and water pollution associated with conventional fossil fuel power plants.

Stoutenburg, E.; Jacobson, M. Z.

2009-12-01

68

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

69

Wave power absorption characteristics of a rocking body  

Microsoft Academic Search

The power characteristics and efficiency of a wave power absorber consisting of a rocking body and a hydro-static power conversion mechanism are examined. The efficiency of the wave power absorber depends both on the shape of the front section of the body and on the local characteristics of the power taking-off mechanism. It is confirmed that the rocking body absorbs

H. Tanaka; M. Saito-O

1981-01-01

70

Starting to experiment with wave power  

NASA Astrophysics Data System (ADS)

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 Faraday induction using coils of wire and magnets.

Hare, Jonathan; McCallie, Ellen

2005-11-01

71

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

72

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

Microsoft Academic Search

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

R. L. Ives; Y. M. Mizuhara; R. V. Schumacher; R. P. Pendleton

1999-01-01

73

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.

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

74

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

2012-11-07

75

Solar flares and focused energy transport by MHD waves  

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

76

Studies of the high power traveling wave interaction  

SciTech Connect

We summarize the results from our continuing study on the high power interaction of electrons and electromagnetic waves in periodic structures. Experiments indicate that power levels in excess of 150 MW are achievable in a low group velocity periodic structure for a pulse duration of less than 100 nsec. The momentum distribution of electrons was measured and energies ranging from 250 kV to 2 MV were detected; this energy spread may have a substantial effect on the design of traveling wave output structures. Another limitation is the large gradients ({approx_gt}200 MV/m) associated with the power levels mentioned above. The high gradient is a direct result of the low group velocity design which in turn was dictated by the need to make the feedback time of the order of the pulse duration. We have developed a method also to analyze quasi-periodic structures which helps us to design output traveling wave structures and optimize these contradictory constraints. {copyright} 1995 {ital American Institute of Physics}.

Kuang, E.; Ivers, J.D.; Kerslick, G.S.; Naqvi, S.A.; Nation, J.A.; Schaechter, L.; Zhang, G. [Laboratory of Plasma Studies and School of Electrical Engineering, Cornell University, Ithaca, New York 14853 (United States)

1995-06-01

77

Solitary waves of Boussinesq equation in a power law media  

Microsoft Academic Search

In this paper, the solitary wave solution of the Boussinesq equation, with power law nonlinearity, is obtained by virtue of solitary wave ansatze method. The numerical simulations are obtained to support the theory.

Anjan Biswas; Daniela Milovic; Arjuna Ranasinghe

2009-01-01

78

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

79

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.

80

Renewable Energy Powered Bicycle  

Microsoft Academic Search

The goal of the project is to convert a standard twenty inch bicycle wheel into a retrofit hydraulic powered wheel. The wheel will harness energy in a self-contained storage unit (the high-pressure accumulator) which will drive a power train including various gears, a motor and a pump.\\u000aThe bike wheel converts braking energy from deceleration to fluid energy at high

Huiming Gong

2012-01-01

81

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

82

Numerical Analysis on Impulse Turbine for OWC Wave Energy Conversion  

Microsoft Academic Search

Oscillating water column wave energy convertor is widely used in the world. The impulse turbine is recently employed for the bi-directional mechanical air power into electricity power. The 2D and 3D numerical model is established in the present paper to investigation the operating performance. The proper mesh style, turbulence model and numerical solutions are employed to study the velocity and

Congbo Xiong; Zhen Liu

2011-01-01

83

DAM-ATOLL - a system for extracting energy from ocean waves  

SciTech Connect

A DAM-ATOLL is a dome-shaped structure located just below th neutral level of the sea. The special dome shape acts as a concentrating device to concentrate the wave energy in both vertical and horizontal directions. The concentrated wave energy is directed to a central core in a manner to create a vortex flow. This vortex, or fluid flywheel, acts as an energy storage device to permit continuous output power from massive pulses of wave energy input power.

Higgins, T.P.; Schreiber, H.G.

1981-01-01

84

78 FR 40132 - Wave Energy Converter Prize Administration Webinar  

Federal Register 2010, 2011, 2012, 2013

...Energy Efficiency and Renewable Energy Wave Energy Converter Prize Administration Webinar...Announcement (FOA), tentatively titled, ``Wave Energy Converter Prize Administration...structuring a prize competition related to wave energy converters. The WWPTO...

2013-07-03

85

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

86

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

87

Design, construction, and ocean testing of a taut-moored dual-body wave energy converter with a linear generator power take-off  

Microsoft Academic Search

This paper presents an overview of the SeaBeavI project which began in the fall of 2006 and culminated in the ocean testing of a 10kW direct-drive wave energy conversion system in the fall of 2007. The SeaBeavI project was an interdisciplinary effort bringing together researchers from electrical, mechanical, and ocean engineering. A systems design approach was used to develop the

David Elwood; Solomon C. Yim; Joe Prudell; Chad Stillinger; Annette von Jouanne; Ted Brekken; Adam Brown; Robert Paasch

2010-01-01

88

Directional energy distribution of wind waves  

Microsoft Academic Search

Two-dimensional ocean wave spectrum developing under the atmospheric surface pressure fluctuations is linearly correlated with that of wind pressure itself, so that angular distribution of energy of ocean surface waves can be determined by directional properties of surface pressure fluctuations with the same frequency to the surface wave.

Noriyuki Iwata

1971-01-01

89

Energy of Waves in a Plasma.  

National Technical Information Service (NTIS)

A formula is given for the energy of an arbitrary linear wave in a plasma which may be magnetized, collisional, homogeneous or weakly inhomogeneous, in terms of the electric and magnetic fields of the wave and derivatives of the wave frequency with respec...

S. P. Auerbach

1978-01-01

90

Update on the design of an offshore wave powered desalination device  

Microsoft Academic Search

A novel offshore wave powered desalination device is currently being studied at the University of Edinburgh. The device is based on a modified version of the Edinburgh duck, a wave energy converter that has been extensively studied since the 1970's. This paper presents the design methodology applied to the concept, from the early numerical studies to the current experimental work.

João Cruz; Stephen Salter

2006-01-01

91

Research in Sweden Concerning the Area of Wave Power.  

National Technical Information Service (NTIS)

Government financed research and development of wave power has been evaluated. The motivation of further contributions are discussed. Future potential and conditions for electric power generation in Swedish coastal waters have been considered. (ERA citati...

R. Hardell

1988-01-01

92

Hydrodynamic principles of wave power extraction.  

PubMed

The hydrodynamic principles common to many wave power converters are reviewed via two representative systems. The first involves one or more floating bodies, and the second water oscillating in a fixed enclosure. It is shown that the prevailing basis is impedance matching and resonance, for which the typical analysis can be illustrated for a single buoy and for an oscillating water column. We then examine the mechanics of a more recent design involving a compact array of small buoys that are not resonated. Its theoretical potential is compared with that of a large buoy of equal volume. A simple theory is also given for a two-dimensional array of small buoys in well-separated rows parallel to a coast. The effects of coastline on a land-based oscillating water column are examined analytically. Possible benefits of moderate to large column sizes are explored. Strategies for broadening the frequency bandwidth of high efficiency by controlling the power-takeoff system are discussed. PMID:22184659

Mei, Chiang C

2012-01-28

93

Landau damping of low and high power slow electrostatic waves  

Microsoft Academic Search

Waves were excited in a warm plasma at frequencies above the lower hybrid frequency and have measured their damping characteristics under a variety of conditions. Strong wave absorption was measured if ..omega..\\/k\\/sub ''\\/ less than or equal to 3 v\\/sub e\\/, in agreement with the predictions of linear Landau damping. At a certain critical power level, consistent with the power

F. J. Paoloni; R. W. Motley; W. M. Hooke; S. Bernabei

1977-01-01

94

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

95

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

96

Millimeter-wave wireless power transfer technology for space applications  

Microsoft Academic Search

Technologies enabling the development of compact systems for wireless transfer of power through radio frequency waves (RF) continue to be important for future space based systems. For example, for lunar surface operation, wireless power transfer technology enables rapid on-demand transmission of power to loads (robotic systems, habitats, and others) and eliminates the need for establishing a traditional power grid. A

Goutam Chattopadhyay; Harish Manohara; Mohammad Mojarradi; Tuan Vo; Hadi Mojarradi; Sam Bae; Neville Marzwell

2008-01-01

97

Energy in a String Wave  

ERIC Educational Resources Information Center

|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…

Ng, Chiu-king

2010-01-01

98

Energy in a String Wave  

ERIC Educational Resources Information Center

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…

Ng, Chiu-king

2010-01-01

99

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

100

Power and energy  

Microsoft Academic Search

Any lingering doubt that the world's electric power industries are driven primarily by politics was probably dispelled last year. Global reverberations of the crisis in the Persian Gulf offered the most striking confirmation, causing wide fluctuations in oil prices and prompting utilities all over the world to reconsider energy technologies not taken seriously since the last oil crisis. In Europe,

Zorpette

1991-01-01

101

Single and multiple waves induced by power absorption  

SciTech Connect

Sub- and supersonic wave fronts produced by heat input have been generated in a shock tube driven by a step current pulse of variable magnitude (4--50 kA, duration up to 160 ..mu..sec). At high current and low fill gas densities, the supersonic mode appears and no substantial compression is possible. The limiting current I/sub c/ to reach this supersonic mode is determined as a function of the fill gas pressure. Front velocities, pressures, and electron densities are measured, and the heating characteristic (maximum enthalpy as function of the net absorbed energy flux) is derived. Scaling laws are obtained for the fluid parameters as a function of fill gas density and current. The measurements are interpreted in terms of one-dimensional wave model calculations. Studies with two stepped power pulse reveal that multiple shocks with a region of substantially increased density can be obtained only if the total current I/sub t/ remains below the critical value I/sub c/. For I/sub t/>I/sub c/, a supersonic heat wave is created after the transient phase, and multiple shocks with increased density can no longer be achieved.

Armstrong, B.; Ahlborn, B.; Liese, W.

1982-02-01

102

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

Microsoft Academic Search

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

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

2007-01-01

103

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.

Coulson, Tracy; Kennedy, Karen

2002-01-01

104

Performance comparison of turbines for wave power conversion  

Microsoft Academic Search

The objective of this paper is to compare the performances of bi-directional turbines under irregular wave condition, which could be used for wave power conversion in the near future. The overall performances in connection with the behavior of oscillating water columns have been evaluated numerically. The types of turbine included in the paper are as follows: (a)Wells turbine with guide

Tae-Ho Kim; Manabu Takao; Toshiaki Setoguchi; Kenji Kaneko; Masahiro Inoue

2001-01-01

105

Powerful gravitational-wave bursts from supernova neutrino oscillations  

NASA Astrophysics Data System (ADS)

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

Mosquera Cuesta, Herman J.; Fiuza, Karen

2004-12-01

106

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

107

Labrador water-wave energy converter  

SciTech Connect

This patent describes a multistage axial flow piston compressor pump, that is capable of being formed into a multi-stage compression chamber pump, having several stage pistons all under one piston rod, that is driven by the energy of the water waves thru various types of power transfer means that converts the energy of the water waves into a concentrated push and pull mechanical force, or operated by push and pull machines/engines in order to effect compression/liquefaction of gases or to create a vacuum thru a one-way axial-air-flow process towards the smallest chamber, and which is capable of being constructed into a large diameter pump, as compressor but more for a vacuum, but the pistons are kept thin and light. It includes at least two adjoining end to end compression cylindrical chambers of equal lengths with common end compression cylindrical chambers of equal lengths with common end walls, decreasing in diameter by chamber after chamber, the last being of the least diameter; a circular piston of corresponding size having piston rings of appropriate types in each the compression chambers, having forward and reverse strokes in the chambers, and movable in response to the actuations of the driving piston rod; a long straight continuous single smooth-surface cylindrical pipe piston rod that passes thru the center holes of the end walls of each and all the the chambers from the first stage to and ending at the last stage, which holds and moves back and forth each the pistons in all the the chambers at the same time in a synchronous movement.

Labrador, G.A.

1992-03-10

108

Wave power p'otential around East Malaysia  

Microsoft Academic Search

Many countries in the world are diversifying their energy resources to utilise renewable and clean energy resources as part of their energy planning. The government of Malaysia has encouraged the development of renewable energy as a fifth source of fuel along with the existing oil, natural gas, coal and hydro in the future planning. Ocean wave is one type of

E. P. Chicmg; P. A. Aswatha; Z. A. Zainal

109

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

110

Role of evanescent waves in power calculations for counterpropagating beams  

NASA Astrophysics Data System (ADS)

A general expression is obtained for the time-average power passing through a plane transverse to the direction of propagation for two counterpropagating electromagnetic beams. Each beam is represented by its plane-wave spectrum, which contains both propagating and evanescent plane waves. The expression clearly shows that, under certain conditions, the evanescent plane waves contribute to the time-average power passing through the plane. This is in contrast to the case of a single electromagnetic beam, in which only the propagating plane waves contribute to the time-average power passing through the plane. The utility of the expression is demonstrated with a practical example: a line current placed over a dielectric slab. Here the counterpropagating beams are the incident and reflected fields in the region between the current and the slab. The expression is applied to a plane in this region, and it is used to determine the time-average power associated with the evanescent waves passing through this plane. This power is then shown to be equal to the time-average power carried by the guided modes of the slab.

Petersson, L. E. Rickard; Smith, Glenn S.

2003-12-01

111

Permanent magnet generator control and electrical system configuration for Wave Dragon MW wave energy take-off system  

Microsoft Academic Search

A permanent magnet generator (PM) control scheme and electrical system configuration for Wave Dragon MW wave energy power take off system is presented in this paper. The characteristics of low pressure hydro turbine are introduced first. To achieve the maximum energy conversion efficiency, a variable speed control scheme of low-head hydro-turbine using IGBT AC\\/DC converter is described. The electrical system

Z. Zhou; W. Knapp; J. MacEnri; H. C. Sorensen; E. Friis Madsen; I. Masters; P. Igic

2008-01-01

112

Multi-electrodes in SAW with square wave ac power  

SciTech Connect

Examines the feasibility of using AC square wave power for multi-electrode submerged arc welding (SAW) by arranging 2 power sources for weld test using two-electrode submerged arc welding. Presents figures showing phase relationship between lead arc current and trail arc current for Scott connected multi-electrode SAW, and arc deflection vs. electrical degrees. Suggests that Scott connection is preferred because it balances the primary line draw. Concludes that the multielectrode submerged arc process with constant potential square wave power increases travel speed and deposition rates which can be added to the economies obtained from a narrow groove joint configuration and the SAW process.

Bunker, T.A.

1982-07-01

113

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

114

Combining wave energy and artificial reef technology for sustainable coastal resource development  

Microsoft Academic Search

Although wave power is a significant alternative energy resource, its commercial deployment is hampered by the high capital cost of mooring structures for the wave energy absorbers. By anchoring the system to an artificial reef instead, harnessing this resource could become more economically feasible. Studies conducted worldwide have shown that reefs can be designed to attract specific species of finfish

Amy E. Hower

1998-01-01

115

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

Microsoft Academic Search

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

H. Eidsmoen

1996-01-01

116

Energy-Conserving Parabolic Wave Equations.  

National Technical Information Service (NTIS)

Energy-conserving versions of the parabolic wave equation model used for underwater sound propagation are derived for stratified media and variable coefficients (depth-dependent and range-dependent). The energy-conserving PWE models are first given for ti...

A. Sundstroem

1992-01-01

117

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

SciTech Connect

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

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

2008-01-01

118

Energy Absorption Structure of Laser Supported Detonation Wave  

Microsoft Academic Search

In Repetitive Pulsed (RP) laser propulsion, when the high energy laser beam is focused in the thruster, Laser Supported Detonation (LSD) wave is generated. This LSD wave converts the laser energy to the enthalpy of the blast wave, which will then apply impulse to the wall of the thruster. Therefore, the energy absorption structure and sustaining condition of LSD wave

Bin Wang; Toshikazu Yamaguchi; Keigo Hatai; Kimiya Komurasaki; Yoshihiro Arakawa

2010-01-01

119

Ultrasonic guided wave energy behavior in laminated anisotropic plates  

NASA Astrophysics Data System (ADS)

A Gaussian beam model coupled with the transfer-matrix technique, was employed to obtain the internal distributions of the energy vector (also called as power density vector or Poynting vectors) of guided ultrasonic plate waves that are modified due to the anisotropy of the media. The spatial pattern of the energy partitioning of the ultrasonic guided waves, previously called plate-wave-flow-patterns, was predicted from the material properties. The model-based predictions of the plate wave flow patterns in fiber reinforced graphite-epoxy laminates, in the form of gray scale images, compared well with the experimental results. In particular, the observed feature that guided waves in plates with structure-induced anisotropy, such as fiber-reinforced composites, tend to follow preferred directions, is predicted by the model. The model provides further insight into the understanding of the generation and propagation of guided wave mode patterns in structure-induced anisotropic plates. Such studies have potential for application in the area of acoustic emission monitoring, structural health monitoring, and stealth materials development.

Balasubramaniam, Krishnan; Krishnamurthy, C. V.

2006-10-01

120

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

121

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

NASA Astrophysics Data System (ADS)

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

Langhamer, Olivia; Wilhelmsson, Dan; Engström, Jens

2009-04-01

122

Radiant energy power source structure  

Microsoft Academic Search

This patent describes a radiant energy power source structure for providing electrical power to a vehicle utilizing radiant energy from a jet engine, the jet engine of the type having a radiant energy emitting combustion chamber formed from spaced apart inner and outer concentric elongated cylindrical liners, the combustion chamber outer liner concentrically surrounded by an elongated annular outer combustion

Doellner

1992-01-01

123

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

124

Teachers' Domain: 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.

125

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

126

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.

127

A simple technique for surface-wave power routing and application to power directing circuits  

Microsoft Academic Search

Electromagnetic surface-waves (SWs) on planar dielectric substrates are generally considered an adverse effect that can degrade the performance of printed circuits, antennas, and arrays. However, with appropriate boundary conditions, SWs can be harnessed as an efficient means of power transport achieving bound, guided-wave propagation along a grounded dielectric slab; surface-wave launchers have been shown to be a useful technique to

Symon K. Podilchak; A. P. Freundorfer; Yahia M. M. Antar

2010-01-01

128

Performance estimation of bi-directional turbines in wave energy plants  

Microsoft Academic Search

Oscillating water column (OWC) based wave energy plants have been designed with several types of bidirectional turbines for\\u000a converting pneumatic power to shaft power. Impulse turbines with linked guide vanes and fixed guide vanes have been tested\\u000a at the Indian Wave Energy plant. This was after initial experimentation with Well’s turbines. In contrast to the Well’s turbine\\u000a which has a

S. Anand; V. Jayashankar; S. Nagata; K. Toyota; M. Takao; T. Setoguchi

2007-01-01

129

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

130

High-powered tunable terahertz source based on a surface-emitted terahertz-wave parametric oscillator  

NASA Astrophysics Data System (ADS)

A high-powered pulsed terahertz (THz)-wave has been parametrically generated via a surface-emitted THz-wave parametric oscillator (TPO). The effective parametric gain length under the noncollinear phase matching condition was calculated for optimization of the parameters of the TPO. A large volume crystal of MgO:LiNbO3 was used as the gain medium. THz-wave radiation covering a frequency range from 0.87 to 2.73 THz was obtained. The average power of the THz-wave was 9.12 ?W at 1.75 THz when the pump energy was 94 mJ, corresponding to an energy conversion efficiency of about 9.7×10-6 and a photon conversion efficiency of about 0.156%. The THz-wave power in our experiments is high enough for practical applications to spectrum analysis and imaging.

Li, Zhongyang; Bing, Pibin; Yao, Jianquan; Xu, Degang; Zhong, Kai

2012-09-01

131

Multi-objective optimization of the airfoil shape of Wells turbine used for wave energy conversion  

Microsoft Academic Search

Wells turbine is one of the technical systems allowing an efficient use of the power contained in oceans’ and seas’ waves with a relatively low investment level. It converts the pneumatic power of the air stream induced by an Oscillating Water Column into mechanical energy. The standard Wells turbines show several well-known disadvantages: low tangential force, leading to low power

M. H. Mohamed; G. Janiga; E. Pap; D. Thévenin

2011-01-01

132

High Average Power, High Energy Short Pulse Fiber Laser System  

Microsoft Academic Search

Recently continuous wave fiber laser systems with output powers in excess of 500W with good beam quality have been demonstrated [1]. High energy, ultrafast, chirped pulsed fiber laser systems have achieved record output energies of 1mJ [2]. However, these high-energy systems have not been scaled beyond a few watts of average output power. Fiber laser systems are attractive for many

Messerly

2007-01-01

133

Fluid viscosity and the attenuation of surface waves: a derivation based on conservation of energy  

NASA Astrophysics Data System (ADS)

More than a century ago, Stokes (1819-1903) pointed out that the attenuation of surface waves could be exploited to measure viscosity. This paper provides the link between fluid viscosity and the attenuation of surface waves by invoking the conservation of energy. First we calculate the power loss per unit area due to viscous dissipation. Next we calculate the power loss per unit area as manifested in the decay of the wave amplitude. By equating these two quantities, we derive the relationship between the fluid viscosity and the decay coefficient of the surface waves in a transparent way.

Behroozi, F.

2004-01-01

134

Study on the generation of high-power terahertz wave from surface-emitted THz-wave parametric oscillator with MgO:LiNbO3 crystal  

NASA Astrophysics Data System (ADS)

High-power nanosecond pulsed THz-wave radiation was achieved via a surface-emitted THz-wave parametric oscillator (TPO). The effective parametric gain length under the condition of noncollinear phase matching was calculated to optimize the parameters of the TPO. Only one MgO:LiNbO3 crystal with large volume was used as gain medium. THz-wave radiation from 0.8 to 2.9 THz was obtained. The maximum THz-wave output was 289.9 nJ/pulse at 1.94 THz when pump power density was 211 MW/cm2, corresponding to the energy conversion efficiency of 3.43×10-6 and the photon conversion efficiency of about 0.05%. The far-field divergence angle of THz-wave radiation was 0.0204 rad at vertical direction and 0.0068 rad at horizontal direction.

Li, Zhongyang; Yao, Jianquan; Xu, Degang; Zhong, Kai; Bing, Pibin; Wang, Jingli

2010-11-01

135

Natural Energy Power and Energy Storing Technology  

NASA Astrophysics Data System (ADS)

With effectuation of Kyoto protocol to reduce CO2 discharging, conventional energy resources are gradually giving way to renewable natural generators. However their weak point of impossibility to control their output themselves will cause some problems with respect to power quality such as voltage and frequency fluctuation. In the meanwhile some kind of electrical energy storage devices like storage batteries, electric double layer capacitors, flywheels are put into practical use. This paper describes the combination of natural energy power and energy storing technologies to solve the power quality problem and to improve their generation values in use.

Takano, Tomihiro

136

Delta wave power: an independent sleep phenotype or epiphenomenon?  

PubMed

Electroencephalographic (EEG) ? waves during non-rapid eye movement sleep (NREMS) after sleep deprivation are enhanced. That observation eventually led to the use of EEG ? power as a parameter to model process S in the two-process model of sleep. It works remarkably well as a model parameter because it often co-varies with sleep duration and intensity. Nevertheless there is a large volume of literature indicating that EEG ? power is regulated independently of sleep duration. For example, high amplitude EEG ? waves occur in wakefulness after systemic atropine administration or after hyperventilation in children. Human neonates have periods of sleep with an almost flat EEG. Similarly, elderly people have reduced EEG ? power, yet retain substantial NREMS. Rats provided with a cafeteria diet have excess duration of NREMS but simultaneously decreased EEG ? power for days. Mice challenged with influenza virus have excessive EEG ? power and NREMS. In contrast, if mice lacking TNF receptors are infected, they still sleep more but have reduced EEG ? power. Sleep regulatory substances, e.g., IL1, TNF, and GHRH, directly injected unilaterally onto the cortex induce state-dependent ipsilateral enhancement of EEG ? power without changing duration of organism sleep. IL1 given systemically enhances duration of NREMS but reduces EEG ? power in mice. Benzodiazepines enhance NREMS but inhibit EEG ? power. If duration of NREMS is an indicator of prior sleepiness then simultaneous EEG ? power may or may not be a useful index of sleepiness. Finally, most sleep regulatory substances are cerebral vasodilators and blood flow affects EEG ? power. In conclusion, it seems unlikely that a single EEG measure will be reliable as a marker of sleepiness for all conditions. PMID:22003323

Davis, Christopher J; Clinton, James M; Jewett, Kathryn A; Zielinski, Mark R; Krueger, James M

2011-10-15

137

Ocean Wave and Tidal Energy Systems.  

National Technical Information Service (NTIS)

The current abstract publication issued bimonthly, contains information on all aspect of ocean thermal energy conversion systems based on exploitation of the temperature difference between the surface water and ocean depth, salinity gradient power systems...

1988-01-01

138

Energy-momentum tensor and conservation laws for water waves  

Microsoft Academic Search

With the averaged variational principles and the energy-momentum tensor, conservation laws for wave action, mass, momentum and energy for slowly varying water waves are derived systematically. For Stokes waves this enables us to derive energy and momentum conservation laws developed by the concept of “radiation stress” from general energymomentum tensor, which is as yet not clearly understood. Moreover the change

Noriyuki Iwata

1974-01-01

139

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

140

Design and performance of high laser power interferometers for gravitational-wave detection  

NASA Astrophysics Data System (ADS)

A prediction of Einstein's general theory of relativity, gravitational waves (GWs) are perturbations of the flat space-time Minkowski metric that travel at the speed of light. Indirectly measured by Hulse and Taylor in the 1970s through the energy they carried away from a binary pulsar system, gravitational waves have yet to be detected directly. The Laser Interferometer Gravitational-wave Observatory (LIGO) is part of a global network of gravitational-wave detectors that seeks to detect directly gravitational waves and to study their sources. LIGO operates on the principle of measuring the gravitational wave's physical signature of a strain, or relative displacement of inertial masses. An extremely small effect whose biggest of expected transient signals on Earth is on the order of one part in 1023, gravitational-wave strain can only be measured by detectors so sensitive to displacement as to encounter the effects of quantum physics. To improve their sensitivities and to demonstrate advanced technologies, the LIGO observatories in Hanford, WA and Livingston, LA underwent an upgrade between fall 2007 and summer 2009 called Enhanced LIGO. This study focuses on the experimental challenges of one of the goals of the upgrade: operating at an increased laser power. I present the design and characterization of two of the interferometer subsystems that are critical for the path towards higher laser power: the Input Optics (IO) and the Angular Sensing and Control (ASC) subsystems. The IO required a new design so its optical components would not be susceptible to high power effects such as thermal lensing or thermal beam drift. The ASC required a new design in order to address static instabilities of the arm cavities caused by increased radiation pressure. In all, I demonstrate the capability of an interferometric GW detector to operate at several times the highest of laser powers previously used. (Full text of this dissertation may be available via the University of Florida Libraries web site. Please check http://www.uflib.ufl.edu/etd.html)

Dooley, Katherine Laird

141

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

142

Ionospheric modification by high-power radio waves  

SciTech Connect

Powerful, high-frequency radio waves have been used to temporarily modify the ionosphere. Thermal and parametric interactions have led to a diverse range of observed phenomena, including generation of density striations and artificial spread-F, enhancements of electron plasma waves, production of extrathermal electron fluxes and enhanced airglow, modification of the D-region temperature and densities, wideband signal attenuation, and self-focusing and scattering of the electromagnetic waves. The physics of ionospheric modification by high-power radio waves is reviewed in the context of our current theoretical understanding; disturbance generation mechanisms are qualitatively described. In addition, results of recent experiments are summarized in which ionospheric irregularities are generated and their evolution and decay processes investigated in detail. The effects and potential controlled applications of these HF ionospheric modifications for various RF systems studies are discussed. The C/sup 3/I scientific community provides an important motivation for these ionospheric modification studies; their increased interaction and active participation in experimental design and interpretation are encouraged.

Duncan, L.M.

1981-04-01

143

Millimeter-wave spectral line radiation from a powerful explosion  

SciTech Connect

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

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

2012-01-15

144

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

145

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

146

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

147

Numerical modeling of 3D weak turbulence driven by high-power VLF pump waves in the topside ionosphere  

NASA Astrophysics Data System (ADS)

Nonlinear interactions have been suggested to account for the missing mechanism of energy losses in the current models of propagation of very low frequency (VLF) waves from powerful transmitters into the magnetosphere. This paper presents the results of study of weak- turbulent coupling between VLF electrostatic waves by means of a novel 3D numerical code, which includes so-called vector nonlinearity. The results virtually reproduce the Demeter satellite observations of intense broadband lower hybrid (LH) electrostatic waves generated by whistler-mode waves from the VLF transmitter NWC.

Galinsky, V. L.; Shevchenko, V. I.; Mishin, E. V.; Starks, M. J.

2011-08-01

148

Wind power and other energy options  

Microsoft Academic Search

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

D. R. Inglis

1978-01-01

149

Wind power and other energy options  

Microsoft Academic Search

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

Inglis

1979-01-01

150

Stormtime Pc5 Hydromagnetic Waves in the Middle Magnetosphere: Modulation of Pc1 Ion Cyclotron Waves and the Role of Medium Energy Ions  

NASA Astrophysics Data System (ADS)

The influence of compressional Pc5 ULF waves on the Pc1-2 electromagnetic ion cyclotron wave generation process involving medium energy ions in the middle magnetosphere is studied using CRRES observations. The two types of waves are seen simultaneously in association with magnetic storms. In the waves studied here, EMIC waves have a short duration in comparison with the Pc5 wave cycle and appear to be modulated by the Pc5 waves. There is also a tendency for the EMIC waves to increase in amplitude during the decrease in Pc5 wave magnetic field, with maximum EMIC wave power shifting to lower frequencies. From consideration of instability theory it is shown that the modulation of the EMIC waves by the Pc5 waves may not be controlled only through the variation of energetic ion temperature anisotropy in an adiabatic process which shows in-phase modulation, but also through the variation in the magnetic field on the ion cyclotron instability, and the variation of the number and energy density of the energetic ions in a non-adiabatic interaction with the Pc5 waves. These latter modulations will be discussed with respect to the CRRES magnetic field, wave and particle data analysed.

Fraser, B. J.; Hu, Y. D.; Korth, A.; Singer, H. J.; Hardy, D. A.; Anderson, R. R.

2001-12-01

151

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

SciTech Connect

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 imposed by the wave energy device on the tower during an extreme storm were estimated and were predicted to be very large. Theoretical and experimental studies have indicated a possible method of reducing the size of the wave energy device by controlling the air pressure in the buoy.

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

1982-09-01

152

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

NASA Astrophysics Data System (ADS)

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

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

2010-06-01

153

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

Microsoft Academic Search

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

H. Eidsmoen

1998-01-01

154

Dynamic analysis of wave energy converter by incorporating the effect of hydraulic transmission lines  

Microsoft Academic Search

A heaving-buoy wave energy converter equipped with hydraulic power take-off is studied in this paper. This wave energy converter system is divided into five subsystems: a heaving buoy, hydraulic pump, pipelines, non-return check valves and a hydraulic motor combined with an electric generator. A dynamic model was developed by considering the interactions between the subsystems in a state space form.

Limin Yang; Torgeir Moan

2011-01-01

155

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

156

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

157

Energy dissipation through wind-generated breaking waves  

NASA Astrophysics Data System (ADS)

Wave breaking is an important process that controls turbulence properties and fluxes of heat and mass in the upper oceanic layer. A model is described for energy dissipation per unit area at the ocean surface attributed to wind-generated breaking waves, in terms of ratio of energy dissipation to energy input, wind-generated wave spectrum, and wave growth rate. Also advanced is a vertical distribution model of turbulent kinetic energy, based on an exponential distribution method. The result shows that energy dissipation rate depends heavily on wind speed and sea state. Our results agree well with predictions of previous works.

Zhang, Shuwen; Cao, Ruixue; Xie, Lingling

2012-09-01

158

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

NASA Astrophysics Data System (ADS)

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

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

2008-12-01

159

Impedance and power fluctuations in linear chains of coupled wave chaotic cavities  

NASA Astrophysics Data System (ADS)

The flow of electromagnetic wave energy through a chain of coupled cavities is considered. The cavities are assumed to be of sufficiently irregular shape that their eigenmodes are described by random matrix theory. The cavities are coupled by electrically short single mode transmission lines. Approximate expressions for the power coupled into successive cavities are derived, and the predictions are compared with Monte Carlo simulations. The analytic formulas separate into a product of factors. Consequently, the distribution of power in the last cavity of a very long chain approaches lognormal. For lossless cavities, signatures of Anderson localization, similar to those of the conductances of quantum wires, are observed.

Gradoni, Gabriele; Antonsen, , Thomas M., Jr.; Ott, Edward

2012-10-01

160

Power MOSFET's for medium-wave and short-wave transmitters  

NASA Astrophysics Data System (ADS)

This paper describes design and performance of a high-frequency power MOST used for switching-mode power amplifiers in the medium-wave (500 kHz to 1.5 MHz) or short-wave (1.5 MHz to 30 MHz) transmitters whose output power is in the vicinity of 1 kW. To obtain the drain-source voltages greater than 200 V with on-resistance remaining approximately 1 Ohm, the offset gate length and field plate length of the high-frequency power MOST are optimized as well as offset gate layer concentration. Employing the molybdenum gate fabricated by RF diode sputter, the MOST operates at high speed with turn-on and turn-off times of 22 and 25 ns, respectively. A high-temperature operation test was performed to assure the stability and reliability of the device. The test results indicate that phosphosilicate glass polarization affects the device reliability only when offset gate layer concentration is much lower than the optimized value.

Ikeda, H.; Ashikawa, K.; Urita, K.

1980-02-01

161

Lineáris generátorok hullámer?m?vek számára Linear Generators for Wave Power Plants Generatoare liniare destinate centralelor electrice bazate pe energia valurilor  

Microsoft Academic Search

Generating power is of great importance in today's world. Due to the pending exhaustion of fossil fuels and to their environmental impact it is crucial to develop clean renewable energy sources. Ocean energy is one of the candidates being a huge, yet unexploited renewable energy source on our planet. In this paper the wave power potential of the Black Sea

Szabó Loránd

162

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

PubMed

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

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

2007-10-01

163

Seasonal and Nightly Variations of Gravity Wave Energy Density Measured by the Purple Crow Lidar  

NASA Astrophysics Data System (ADS)

The Purple Crow Lidar(PCL) is a large power-aperture product monostatic laser radar which has been in operation at the Delaware Observatory near the campus of The University of Western Ontario since 1992. The PCL is capable of making simultaneous measurements of Rayleigh, Raman and resonance fluorescence scattering, which allows temperature, constituent density and gravity wave parameters to be simultaneously determined from the troposphere to the lower thermosphere. Average nightly gravity wave energy density has been calculated from the Rayleigh-scatter system measurements. The gravity wave energy density is typically largest in the upper stratosphere relative to the mesosphere. There are no clear seasonal trends, but the energy density appears to decrease rapidly in the fall relative to the late summer. The nightly variability of the gravity wave energy density is often extremely large, with 50 to 100% RMS fluctuations about the mean energy at all heights.

Sica, R. J.; Cole, I.; Argall, S.

2005-12-01

164

Power and energy  

SciTech Connect

According to the author, in response to financial and competitive pressures, U.S. utilities have been proposing and consummating mergers on a scale not seen since the 1930s. The author discusses how such proposals have far-reaching consequences for U.S. transmission networks, and, along with concrete proposals for new federal clean air legislation, hint at structural changes in the utility industry. Competitive and environmental concerns are seen as having fostered technical advances, particularly in the harnessing of renewable- and alternative-energy sources and in the use of computers to monitor and control interconnected high-voltage transmission networks.

Zorpette, G

1990-01-01

165

Wave energy and public opinion in the state of Oregon, U.S.A  

Microsoft Academic Search

Countries have been developing renewable energies for quite some time now, and people are starting to think of them as being affordable, readily available, and good for the environment. The time has come to develop wave energy. Governments around the world are finally seeing the benefits of its unstoppable grace and power and are starting to account for it in

Maria Stefanovich

2009-01-01

166

Machines and Drives Comparison for Low-Power Renewable Energy and Oscillating Applications  

Microsoft Academic Search

The objective of this paper is to analyze, test, and compare machines and drives in oscillating applications. In particular, this paper is focused on low-power wave energy generator applications, such as autonomous weather and monitoring buoys with power requirements in the 100 W and less range. Due to the oscillating motion of waves, the ocean environment can require bidirectional and

T. K. A. Brekken; H. M. Hapke; C. Stillinger; J. Prudell

2010-01-01

167

Apparatus for storing the energy of ocean waves  

Microsoft Academic Search

A system is described for manufacturing hydrogen gas which utilizes the energy of surface waves in a liquid, such as an ocean. The system first converts the energy of surface waves to mechanical energy by apparatus comprising a buoyant helical member mounted for rotation about an axis. The pitch of the helical member can be matched to the length of

Lapeyre

1983-01-01

168

Apparatus for storing the energy of ocean waves  

Microsoft Academic Search

A system is described for manufacturing hydrogen gas which utilizes the energy of surface waves in a liquid, such as an ocean. The system first converts the energy of surface waves to mechanical energy by apparatus comprising a buoyant helical member mounted for rotation about an axis. The pitch of the helical member can be matched to the length of

Lapeyre

1984-01-01

169

Energy Conservation in the Electric Power System.  

National Technical Information Service (NTIS)

The possibilities for energy conservation in the Norwegian electric power supply system are analysed. This power system is based exclusively on hydroelectric power and consists of water storage reservoirs, pipes and tunnels for water transport, power plan...

A. Killingtveit K. Tvinnereim

1983-01-01

170

Enhancement of particle-wave energy exchange by resonance sweeping.  

National Technical Information Service (NTIS)

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...

H. L. Berk B. N. Breizman

1995-01-01

171

The role of the electron energy distribution in ionization waves  

Microsoft Academic Search

Time-resolved electron energy distribution measurements have been made in p, r, s and high-current types of ionization wave in neon discharges. The different types of wave at low current are shown to be associated with spatial resonances of the electron gas. The physical nature of the resonance mechanism accounts for the constancy of E?, characteristic of each wave type, and

S W Rayment

1974-01-01

172

A wave scattering theory of solar seismic power haloes  

NASA Astrophysics Data System (ADS)

Spatial maps of the high-pass frequency filtered time-averaged root-mean-squared (RMS) Doppler velocities tend to show substantial decrements within regions of strong field and curiously, randomly distributed patches of enhancement in the vicinity. We propose that these haloes or enhancements are a consequence of magnetic-field-induced mode mixing (scattering), resulting in the preferential powering of waves that possess strong surface velocity signatures (i.e. scattering from low to high wavenumbers). Evidently, this process can occur in the reverse, and therefore in order to determine if the haloes are indeed caused by mode mixing, we must answer the question: how are acoustic waves scattered by magnetic fields? Through simulations of the interactions between waves and sunspots and models of plage, we demonstrate that the high to low modal order scattering channels are favoured. With increasing frequency and consequently, decreasing wavelength, a growing number of modes are scattered by the sunspot, thereby rendering the enhancements most visible around the high-frequency parts of the spectrum. The haloes obtained from the simulations are on the same order of magnitude but weaker than those observed. We also present observational evidence to support this theory: observations of active region AR9787 are firstly frequency filtered to isolate the 5-6 mHz signals and secondly, decomposed into three wavenumber bandpasses, l - [0,400], [400,800], [800,2222]. With increasing wavenumber, the extent of the halo effect is seen increase dramatically, in line with theoretical expectation.

Hanasoge, S. M.

2009-08-01

173

Noise powered nonlinear energy harvesting  

NASA Astrophysics Data System (ADS)

The powering of small-scale electronic mobile devices has been in recent years the subject of a great number of research efforts aimed primarily at finding an alternative solution to standard batteries. The harvesting of kinetic energy present in the form of random vibrations (from non-equilibrium thermal noise up to machine vibrations) is an interesting option due to the almost universal presence of some kind of motion. Present working solutions for vibration energy harvesting are based on oscillating mechanical elements that convert kinetic energy via capacitive, inductive or piezoelectric methods. These oscillators are usually designed to be resonantly tuned to the ambient dominant frequency. However, in most cases the ambient random vibrations have their energy distributed over a wide spectrum of frequencies, especially at low frequency, and frequency tuning is not always possible due to geometrical/dynamical constraints. We present a new approach to the powering of small autonomous sensors based on vibration energy harvesting by the exploitation of nonlinear stochastic dynamics. Such a method is shown to outperform standard linear approaches based on the use of resonant oscillators and to overcome some of the most severe limitations of present strategies, like narrow bandwidth, need for continuous frequency tuning and low power efficiency. We demonstrate the superior performances of this method by applying it to piezoelectric energy harvesting from ambient vibration.

Gammaitoni, Luca; Neri, Igor; Vocca, Helios

2011-04-01

174

Gravity wave kinetic, potential, and vertical fluctuation energies as indicators of different frequency gravity waves  

NASA Astrophysics Data System (ADS)

An advantage of examining atmospheric gravity waves using high vertical-resolution radiosonde data over other measurement techniques is that horizontal wind, temperature, and vertical ascent rate can be measured directly. This allows the kinetic, potential, and vertical velocity fluctuation energies to be derived independently. Each of these gravity wave energies is shown to have sensitivity to different gravity wave frequencies. Observed correlations among these energies are consistent with this, and simulations of these correlations are shown to constrain gravity wave frequency spectra. The climatology of these energies shows quite different variations with month of the year and with latitude such that the vertical fluctuation energy seems to be a better indicator of convectively forced higher-frequency gravity waves.

Geller, Marvin A.; Gong, Jie

2010-06-01

175

Atomspheric Dscharge using a High Power Millimeter Wave and its Applicaltion to Rocket Propulsion  

Microsoft Academic Search

Microwave rocket is an application of atmospheric discharge using a high power millimeter-wave beam. When a high power pulsed millimeter-wave beam is provided into a focusing reflector, atmospheric discharge arises in the vicinity of the focal point. The induced plasma absorbs the following part of the millimeter-wave pulse and propagates towards the beam source while generating a shock wave. The

Y. Oda; K. Komurasaki

2007-01-01

176

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

177

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

178

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

179

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

180

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

181

Free energy in plasmas under wave-induced diffusion  

SciTech Connect

When waves propagate through a bounded plasma, the wave may be amplified or damped at the expense of the plasma kinetic energy. In many cases of interest, the primary effect of the wave is to cause plasma diffusion in velocity and configuration space. In the absence of collisions, the rearrangement of the plasma conserves entropy, as large-grain structures are mixed and fine-grain structures emerge. The maximum extractable energy by waves so diffusing the plasma is a quantity of fundamental interest; it can be defined, but it is difficult to calculate. Through the consideration of specific examples, certain strategies for maximizing energy extraction are identified.

Fisch, N.J. (Princeton Univ., NJ (United States). Plasma Physics Lab.); Rax, J.M. (CEA Centre d'Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France))

1993-05-01

182

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

183

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

184

Wave power conversion by point absorbers - A Norwegian project  

NASA Astrophysics Data System (ADS)

This paper describes a spherical buoy, which can perform heaving oscillation relative to a strut joined to an anchor on the sea bed. The buoy is supplied with latching means for optimum phase control and with an air turbine for power take-off. The electrical generator is rated at 0.4 MW. An estimate is given for the cost of a 200 MW power plant and for its annual energy production if placed off the west coast of Norway. The estimated electricity cost is approximately 4 p/kWh. At the present stage of the research, it is consequently not competitive with hydroelectric power plants in Norway. However, there are several options for cost reduction of a power-buoy plant.

Budal, K.; Falnes, J.

1982-04-01

185

Energy flux of edge waves travelling along a continental shelf  

Microsoft Academic Search

Longuet-Higgins (1964) originally recognised that the energy flux defined by pressure work from the equations of motion was not the same as the mean energy density times the group velocity for planetary waves on a beta-plane. This paper addresses a similar paradox for linear, long period edge waves on an arbitrary shaped (in the offshore direction) straight continental shelf. The

F. A. Shillington; G. B. Brundrit

1986-01-01

186

Traveling-Wave Direct Energy Converter for Fusion Products  

Microsoft Academic Search

A Traveling-Wave Direct Energy Converter (TWDEC), which is designed to recover kinetic energy of fusion protons escaped from a FRC\\/ D^3He fusion reactor, is studied by numerical calculation and computer simulation. To develop a simulation code, a transmission line loop for an electrostatic traveling wave is designed using lumped constant elements L, C, R. Electrostatic coupling between proton beam and

Kunihiro Sato; Hideaki Katayama

1999-01-01

187

METHODOLOGICAL NOTES: Energy fluxes during the interference of electromagnetic waves  

Microsoft Academic Search

Expressions are given for the interference energy flux (IEF) of the active and reactive components of co- and counterpropagating waves with an arbitrary structure of their electromagnetic field. The formation conditions of the IEF and its role in energy transfer processes are analyzed in the examples of homogeneous plane waves in an absorbing medium, directed planar-waveguide modes, and a system

S. A. Afanas'ev; D. I. Sementsov

2008-01-01

188

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

National Technical Information Service (NTIS)

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 ...

L. Smith D. W. Lane

1988-01-01

189

Advanced Gunn diode as high power terahertz source for a millimetre wave high power multiplier  

NASA Astrophysics Data System (ADS)

An advanced step-graded Gunn diode is reported, which has been developed through joint modelling-experimental work. The ~ 200 GHz fundamental frequency devices have been realized to test GaAs based Gunn oscillators at sub-millimetre wave for use as a high power (multi mW) Terahertz source in conjunction with a mm-wave multiplier, with novel Schottky diodes. The epitaxial growth of both the Gunn diode and Schottky diode wafers were performed using an industrial scale Molecular Beam Epitaxy (V100+) reactor. The Gunn diodes were then manufactured and packaged by e2v Technologies (UK) Plc. Physical models of the high power Gunn diode sources, presented here, are developed in SILVACO.

Amir, F.; Mitchell, C.; Farrington, N.; Missous, M.

2009-09-01

190

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

191

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

192

Measurements of radiated elastic wave energy from dynamic tensile cracks  

NASA Astrophysics Data System (ADS)

To determine the conditions under which elastic waves are radiated from crack sources, dynamic tensile cracks were propagated in glass samples in the double cantilever beam geometry. This geometry allows simple calculation of the strain energy release rate G at initiation from measured parameters of crack length, applied crack opening force, and crack opening displacement. Partial control over the strain energy state in the sample at fracture initiation, and hence G at initiation, was achieved by varying the geometry of the notch tip from which the fracture emanates. Elastic wave displacements were monitored with a broadband capacitance transducer with a pointlike probe. A single component of elastic wave displacement (parallel to the crack plane and perpendicular to the crack propagation direction) was measured. Two fracture configurations were investigated: (1) "primary fracture" in glass plates of dimension 305×102 ×12.7 mm and (2) "secondary fracture" in previously fractured glass plates of the same dimensions, bonded intermittently along the fracture plane. Primary fracture experiments afforded a means of investigating elastic wave radiation from mode I cracks in a highly brittle material, such that the strain energy released by the fracture is partitioned into fracture surface energy of the newly formed crack walls and radiated elastic wave energy; negligible energy is expended in ductile or frictional processes. Secondary fracture experiments afforded a means of investigating elastic wave radiation in the case of varying fracture surface energy along the crack path. For primary fracture, measurable elastic waves from the macrofracture were generated in 31% of the 16 dynamic fracture events monitored. The condition for radiation of measurable waves from these fractures appears to be a local abrupt change in the fracture path direction, such as occurs when the fracture intersects a surface flaw. For the five events with measurable elastic waves, the ratio of radiated elastic wave energy in the measured component to the fracture surface energy of the macrocrack was 0.0001-0.001. For secondary fracture, 100% of the 13 events monitored showed measurable elastic waves. The ratio of radiated elastic wave energy in the measured component to fracture surface energy was 0.001-0.01, or 10 times greater than for primary fracture. The observed value of G at crack initiation for both primary and secondary fracture ranged from 3 to 48 J m-2. When the time window for radiated elastic wave energy calculation was restricted to a few microseconds after the first arrival, a weak correlation of radiated elastic wave energy with initiation G value was observed for secondary fractures.

Boler, Frances M.

1990-03-01

193

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

194

Energy Storage Options for Space Power.  

National Technical Information Service (NTIS)

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, therma...

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

1985-01-01

195

Autonomous Low Power Microsystem Powered by Vibration Energy Harvesting  

Microsoft Academic Search

This paper reports, for the first time, the implementation of a microsystem powered entirely from ambient vibrations. Sufficient electrical energy is harvested to power a radio-frequency (RF) linked accelerometer based microsystem. The microsystem is energy aware and will adjust the measurement\\/transmit duty cycle according to the available energy; this is typically every 50 seconds during normal operation. The system is

R. N. Torah; M. J. Tudor; K. Patel; I. N. Garcia; S. P. Beeby

2007-01-01

196

Group velocity and power flow relations for surface waves in stratified anisotropic media  

Microsoft Academic Search

SUMMARY It is well known that in a linear, lossless, homogeneous but anisotropic medium, monochromatic plane electromagnetic waves propagating with wave vector K carry power in a direction given by the normal to the dispersion surface L = W (s), which is the solution of the plane wave dispersion

H. Bertoni; A. Hessel

1965-01-01

197

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

Microsoft Academic Search

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

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

2011-01-01

198

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

199

Near field effects of millimeter-wave power transmission for medical applications  

NASA Astrophysics Data System (ADS)

An integration of micro devices system and wireless power transmission (WPT) technology offers a great potential to revolutionize current health care devices. The system integration of wireless power transmission devices with smart microsensors is crucial for replacing a power storage devices and miniaturizing wireless biomedical systems. Our research goal is to replace battery power supply with an implantable millimeter-wave rectenna. Recently, a hat system with a small millimeter-wave antenna which can feed millimeter-wave power to thin-film rectenna array embedding Schottky diodes was introduced for neural sensing and stimulation applications. In order to prove the design concept and investigate wireless power coupling efficiency under the system design, near-field wireless power transmission was studied in terms of wave frequency and distance. Also, in this paper, we will present the influence of biological objects to the wireless power transmission, simulating the experimental conditions of human objects for future medical applications.

Yoon, Hargsoon; Song, Kyo D.; Lee, Kunik; Kim, Jaehwan; Choi, Sang H.

2011-03-01

200

High Power Pulse Energy System Concept.  

National Technical Information Service (NTIS)

New advances in capacitor technology create exciting opportunities in size and weight reduction for high-power, pulse energy systems having a broad range of applications. Characteristics of a proposed high power pulse energy system, formed by combining a ...

H. L. Lee G. Mason K. Kern

1988-01-01

201

Exploring Energy, Power, and Transportation Technology.  

ERIC Educational Resources Information Center

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

Bowers, Donovan; Kellum, Mary

202

Powerful gravitational-wave bursts from supernova neutrino oscillations  

Microsoft Academic Search

During supernova core collapse and bounce resonant active-to-active, as well as active-to-sterile, neutrino (v) oscillations can take place. Over this phase weak magnetism increases antineutrino mean free paths, and thus its luminosity. Because oscillations feed mass-energy into the target v species, the large mass-squared difference between v states implies a huge amount of power to be given off as gravitational

Herman J. Mosquera Cuesta; Karen Fiuza

2004-01-01

203

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

204

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

205

Experimental and computational analysis on guide vane losses of impulse turbine for wave energy conversion  

Microsoft Academic Search

This paper deals with the detailed flow analysis of impulse turbine with experimental and computed results for wave energy power conversion. Initially, several turbulence models have been used in two-dimensional (2-D) computational fluid dynamic (CFD) analysis to find a suitable model for this kind of slow speed unconventional turbine. Experiments have been conducted to validate the CFD results and also

A. Thakker; T. S. Dhanasekaran

2005-01-01

206

Maximum energy gain in a nonlinear plasma wave  

SciTech Connect

The trapping and acceleration of a test electron in a nonlinear plasma wave is analyzed in one-dimension using Hamiltonian dynamics. The plasma wave is described by a nonlinear, cold fluid model. The maximum energy gain and the minimum energy required for trapping of the test electron are determined. The separatrix is plotted for several values of plasma wave amplitude. In the large wave amplitude limit, the maximum energy of a trapped electron scales as 2{gamma}{sup 2}{sub {ital p}}{ital E}{sup 2}{sub {ital z}}, where {gamma}{sub {ital p}} is the relativistic factor associated with plasma wave phase velocity and {ital E}{sub {ital z}} is the electric field amplitude of the nonlinear plasma wave. This is in contrast to the well-know results for a sinusoidal wave, in which the maximum energy scales as 4{gamma}{sup 2}{sub {ital p}}{ital E}{sub {ital z}}. As the nonlinear plasma wave approaches wavebreaking, the maximum energy is given by {gamma}{sub max}{implies}4{gamma}{sup 3}{sub {ital p}}-3{gamma}{sub {ital p}}, where {gamma}{sub max} is the relativistic factor of the trapped electron. {copyright} 1995 {ital American Institute of Physics}.

Esarey, E.; Pilloff, M. [Beam Physics Branch, Plasma Physics Division Naval Research Laboratory, Washington, DC 20375-5346 (United States)

1995-06-01

207

Suprathermal electrons generated by the interaction of powerful radio wave with the ionosphere  

Microsoft Academic Search

We present two sets of observations of suprathermal electrons, produced by the interaction of powerful radio wave with the ionosphere, as seen using the incoherent scatter radar (ISR) technique. The observational data are compared with the theory of multiple acceleration of electrons in the strongly excited resonance region near the reflection point of the powerful radio wave. The structure of

A. V. Gurevich; H. C. Carlson; G. M. Milikh; K. P. Zybin; F. T. Djuth; K. Groves

2000-01-01

208

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

209

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

SciTech Connect

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

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

2008-11-13

210

High power harmonic gyro-amplifiers for millimeter-wave radar  

Microsoft Academic Search

Advances in electron gun and circuit technology have made it possible to design compact high power (multi-kW wave, tens-kW peak) gyro-amplifiers operating at millimeter wave frequencies employing conventional magnet technology. The devices being developed have the potential to increase the power available to the millimeter wave system designer by over an order of magnitude in a configuration compatible with system

C. M. Armstrong; G. S. Park; A. K. Ganguly; R. H. Kyser; J. L. Hirshfield

1994-01-01

211

Excitation of artificial airglow by high power radio waves from the SURA ionospheric heating facility  

Microsoft Academic Search

The SURA facility for generation of high power radio waves, located near the village of Vasil'sursk USSR, operates between 4.5 and 9.0 MHz and has a maximum effective radiated power (ERP) of 300 MW. Nonlinear interactions between the HF radio waves and F-layer plasma occur near the electromagnetic wave reflection point. Energetic electrons are accelerated out of the interaction regions

P.A. Bernhardt; W. A. Scales; S. M. Grach; A. N. Keroshtin; D. S. Kotik; S. V. Polyakov

1991-01-01

212

Two Energy Types in Wave Motion and Their Relation to Group and Wave Velocity  

Microsoft Academic Search

The energy of an element in a wave motion can be of two kinds: first, non-interactive like the energy of a set of independent pendulum bobs, and second, interactive like the potential energy of an element of a stretched string which is dependent only on the relative position of the neighboring elements. In the former case the group velocity is

Lewi Tonks

1929-01-01

213

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

214

Numerical Prediction of Blast-Wave Flows Outside and inside a Power House of a Nuclear-Power Generating Station.  

National Technical Information Service (NTIS)

The blast-wave flows both outside and inside a power house of a nuclear-power generating station, from an accidental explosion of an explosive like TNT or its equivalent during transportation past the power house by a train, are studied numerically and as...

J. J. Gottlieb T. Saito K. Y. Zhang

1985-01-01

215

Wave Energy - Basis for Planning of EFUD 84.  

National Technical Information Service (NTIS)

Two main alternatives are discussed, a quick discontinuance and increase of research contributions, resp. potential of wind power in Sweden seems to be insufficient. The only positive effort can be the export of wave power plants. The planning group has n...

1983-01-01

216

Wave-Powered Unmanned Surface Vehicle as a Station-Keeping Gateway Node for Undersea Distributed Networks.  

National Technical Information Service (NTIS)

By analyzing data from a long-duration deployment of four wave- powered unmanned surface vehicles called Wave Gliders, an assessment of operating characteristics informs the potential utility of the Wave Glider in an undersea distributed network as a repl...

T. W. Rochholz

2012-01-01

217

Energy cascading in the beat-wave accelerator  

SciTech Connect

A review is given of energy cascading in the beat-wave accelerator. The properties of the electromagnetic cascade and the corresponding plasma-wave evolution are well understood within the framework of an approximate analytic model. Based on this model, idealized laser-plasma coupling efficiencies of the order of 10% do not seem unreasonable. 28 refs.

McKinstrie, C.J.; Batha, S.H.

1987-01-01

218

Binding Energy Calculations Using the Molecular Orbital Wave Function.  

National Technical Information Service (NTIS)

The molecular orbital wave function is used in describing the 4 N-nuclei internal wave function. Using the variational technique the binding energies of the nuclei exp 12 C, exp 16 O, exp 20 Ne and exp 24 Mg are calculated using different Skyrm interactio...

M. Y. M. Hassan A. Rabie E. H. Ismail

1982-01-01

219

Dissipation of acoustic-wave energy at small gas bubbles  

Microsoft Academic Search

Bubble formation at fission-fragment tracks is one of the major factors which affect the dynamics of homogeneous solution reactors. The rate of bubble growth is also of importance. In the present paper, the behavior of gas bubbles in the field of a sound wave is analyzed. Specifically, the dissipation of acoustic-wave energy at a gas bubble is studied in the

A. N. Sizov

1975-01-01

220

Power Technologies Energy Data Book. Third Edition.  

National Technical Information Service (NTIS)

In 2002, the Energy Analysis Office of the National Renewable Energy Laboratory (NREL) developed the first version of the Power Technologies Energy Data Book for the Office of Power Technologies of the U.S. Department of Energy (DOE). The main purpose of ...

2005-01-01

221

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

SciTech Connect

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

Takahashi, K.; Kajiwara, K.; Oda, Y.; Kasugai, A.; Kobayashi, N.; Sakamoto, K. [Japan Atomic Energy Agency, 801-1 Mukoyama, Naka, Ibaraki 311-0193 (Japan); Doane, J.; Olstad, R. [General Atomics, P.O. Box 85608, San Diego, California 92186-5608 (United States); Henderson, M. [ITER Organization, CS90 046, 13067 St. Paul lez Durance Cedex (France)

2011-06-15

222

Acoustic Intensity: Energy Transfer, Wave Properties and Applications.  

National Technical Information Service (NTIS)

This study explores the physical interpretations of the instantaneous intensity, active intensity, and reactive intensity vectors in terms of energy transfer and wave properties in the nearfield of a general monochromatic sound field. The time dependent e...

J. A. Mann

1988-01-01

223

Passage of a powerful HF radio wave through the lower ionosphere as a function of initial electron density profiles  

Microsoft Academic Search

The results of numerical modelling of powerful HF radio wave propagation through the ionosphere plasma are presented. Comparison of the heating wave parameters with those of a low powerwave gives the possibility to study the self-action of the powerful HF wave. At low altitudes the ‘translucence’ of the ionosphere plasma takes place. At high altitudes the wave absorption sharply increases.

E. G. Belova; A. B. Pashin; W. B. Lyatsky

1995-01-01

224

Computational study of shock wave control by pulse energy deposition  

NASA Astrophysics Data System (ADS)

We have developed a computational code based on the axisymmetric Navier-Stokes equations with thermochemical kinetics for assessing wave drag reduction and other effects in pulse-energy deposition ahead of a bow shock by means of full simulations from generation of a laser-induced blast wave to interaction with the bow shock. Thermochemical nonequilibrium computations can reproduce the process of blast wave formation with laser ray tracing, and the computed low-density core inside the blast wave has a teardrop-like shape, depending on the laser input condition. The flowfield interacting with a bow shock formed in Mach 5 flow was computed. The result suggests that the shape of the low-density core affects the resultant wave drag, and parameters of an incident laser beam should be taken into account in exploring the optimal condition of the proposed wave-drag scheme.

Ohnishi, N.; Tate, M.; Ogino, Y.

2012-11-01

225

Electron-wave quantum well energy band-pass filters  

Microsoft Academic Search

In this study, energy band-pass filters composed of superlattice resonance tunnelling structures are proposed. Based on the analogy between electron waves propagating in superlattice structures and electromagnetic waves travelling in transmission lines, the method developed for designing a coupled cavity filter in microwave engineering can be adopted to provide a first-cut design of energy band-pass filter to fulfil specific requirements.

C. C. Chang; C. S. Kou

1999-01-01

226

Computer Simulation of a Traveling-Wave Direct Energy Converter  

Microsoft Academic Search

Beam-circuit code is presented to simulate a Traveling-Wave Direct Energy Converter (TWDEC), which recovers the energy of fusion protons escaping from a FRC\\/D3He fusion reactor. A transmission line loop for propagation of the electrostatic traveling wave is designed using lumped constant elements L.C.R. Electrostatic coupling between proton beam and circuits is treated by directly solving Poisson's equation. Circuit equations are

Hideaki Katayama; Kunihiro Sato; Fujio Miyawaki

1999-01-01

227

Distinct propagating fast wave trains associated with flaring energy releases  

NASA Astrophysics Data System (ADS)

Context. Large-scale fast waves with perturbation of the EUV emission intensity are well resolved in both temporal and spatial scale by SDO/AIA. These waves are prone to propagate along the magnetic field line. Aims: We aim to probe the link between propagating fast wave trains and flaring energy releases. By measuring the wave parameters, we reveal their nature and investigate the potential to diagnose the energy source and waveguide. Methods: The spatial and temporal evolution of the wave amplitude and propagating speed are studied. The correlation of individual wave trains with flare-generated radio bursts is tested. Results: The propagating wave pattern comprises distinct wave trains with varying periods and wavelengths. This characteristic signature is consistent with the patterns formed by waveguide dispersion, when different spectral components propagate at different phase and group speeds. The wave train releases are found to be highly correlated in start time with the radio bursts emitted by the non-thermal electrons that were accelerated in bursty energy releases. The wave amplitude is seen to reach the maximum midway during its course. This can be caused by a combined effect of the waveguide spread in the transverse direction and density stratification. The transverse amplitude distribution perpendicular to the wave vector is found to follow approximately a Gaussian profile. The spatial structure is consistent with the kink mode that is polarised along the line-of-sight. The propagating speed is subject to deceleration from ~735-845 km s-1 to ~600 km s-1. This could be caused by the decrease in the local Alfvén speed and/or the projection effect.

Yuan, D.; Shen, Y.; Liu, Y.; Nakariakov, V. M.; Tan, B.; Huang, J.

2013-06-01

228

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

229

Misconceptions about the energy of waves in a strained string  

NASA Astrophysics Data System (ADS)

The localization of the elastic potential energy associated with transverse and longitudinal waves in a stretched string is discussed. Some misunderstandings about different expressions for the density of potential energy encountered in the literature are clarified. The widespread opinion regarding the inherent ambiguity of the density of elastic potential energy is criticized.

Butikov, Eugene I.

2012-09-01

230

Energy of tsunami waves generated by bottom motion  

Microsoft Academic Search

In the vast literature on tsunami research, few articles have been devoted to energy issues. A theoretical investigation on the energy of waves generated by bottom motion is performed here. We start with the full incompressible Euler equations in the presence of a free surface and derive both dispersive and non-dispersive shallow-water equations with an energy equation. It is shown

Denys Dutykh; Frédéric Dias

2008-01-01

231

High Average Power, High Energy Short Pulse Fiber Laser System  

SciTech Connect

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

Messerly, M J

2007-11-13

232

Catalytic Alpha-Channeling of Wave Energy in Mirror Devices  

NASA Astrophysics Data System (ADS)

The possibilities for alpha-channeling in mirror reactors are significantly broadened if the alpha particle energy is channeled to minority ions rather than fuel ions. The minority ions then collide preferentially with the fuel ions, thereby completing the channeling of the alpha energy to the fuel ions. This technique, which relaxes the wave requirements since the wave need not now resonate both with the fuel ions and alpha particles, may be thought of as ``catalytic alpha channeling.'' It may be particularly important in mirror fusion, as opposed to tokamak fusion, since the channeling effect in mirror machines exploits very different wave modes in very different ways.

Zhmoginov, Andrey; Fisch, Nathaniel

2011-11-01

233

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

234

A dual-resonant reflector in powerful relativistic backward wave oscillator  

SciTech Connect

A dual-resonant reflector is proposed to suppress the radio frequency breakdown and enhance the reflection in a high power relativistic backward wave oscillator. The backward wave is reflected by two reflector cavities step by step, therefore, a high reflectivity is obtained. A preliminary high power microwave generation experiment of backward wave oscillator (BWO) with a general resonant reflector and a dual-resonant reflector was carried out. A microwave with power over 3 GW, frequency 9.6 GHz, efficiency 30%, and pulse width 22 ns was generated. The experiment results show that the efficiency of BWO with a dual-RR is enhanced about 2%-6%.

Song Wei; Chen Changhua; Zhang Ligang; Hu Yongmei; Yang Meng; Zhang Xiaowei; Zhang Lijun [Science and Technology on High Power Microwave Laboratory, Northwest Institute of Nuclear Technology, Xi'an, Shanxi 710024 (China)

2011-06-15

235

Power management in energy harvesting sensor networks  

Microsoft Academic Search

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

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

2007-01-01

236

Energy analysis of the Solar Power Satellite  

Microsoft Academic Search

The energy requirements to build and operate the proposed Solar Power Satellite are evaluated and compared with the energy it produces. Because the technology is so speculative, uncertainty is explicitly accounted for. For a proposed 10-gigawatt satellite system, the energy ratio, defined as the electrical energy produced divided by the primary nonrenewable energy required over the lifetime of the system,

R. A. Herendeen; T. Kary; J. Rebitzer

1979-01-01

237

Power shock: The next energy revolution  

SciTech Connect

Most experts seem to think that our decades-old oil- and coal-based energy systems will barely change. Developments around the world are already proving them wrong, however. We may soon witness the most dramatic changes in the world energy economy in a hundred years. This article discusses the power shift of the future from coal and oil fueled electric power to energy sources of the future such as wind power, photovoltaics, and solar heating.

Flavin, C.

1996-01-01

238

Antisymmetric Wave Functions for Mixed Fermion States and Energy Convexity  

SciTech Connect

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

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

2011-01-01

239

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

240

Energy Transfer into Cross-Waves by Wavemakers  

NASA Astrophysics Data System (ADS)

In the long channels, the cross-waves derive their energy directly from wavemaker not only from basic flow. In the present talk we show how cross-waves are generated in long rectangular channels by wavemaker even without having to take into account the presence of any basic flow waves. Here we apply Lamè's method of superposition for the first time in such channel geometry. This method allows one to construct a simple mathematical model, which shows how the cross-waves can be generated directly by the wavemaker motion. This mathematical model of the resonant cross-wave excitation is the easiest way to study pattern formation on fluid free surface. Our experimental observations agree with the theoretical results.

Krasnopolskaya, Tatyana; Meleshko, Viatcheslav; Spektor, Viacheslav

2010-11-01

241

Evaluating double-angular power spectrum of waves in stochastic media by random walk  

Microsoft Academic Search

A propagation model was recently developed to characterize the waves between two communicating volumes in the presence of multipath stochastic media [1]. A double-angular power spectrum (DAPS) is a crucial part of this model. It relates the directional propagation of waves on the transmitting side to that on the receiving side. To obtain the DAPS of a system, one may

Jie Xu

2010-01-01

242

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

243

Strong motion waves estimation for seismic control of nuclear power plant  

Microsoft Academic Search

The problem of forecasting in general and in real-time of the behavior of seismic wave is discussed. Seismic waves classification on the base of principle axis transformation and evolutionary power spectrum estimation is provided for it implementation in an intelligent hybrid model. A hybrid model for real-time forecasting of strong motion acceleration on the bases of general, tectonic, seismic and

Svetla Tsoneva Radeva; Raimar Josef Scherer; Dimitar Radev

2005-01-01

244

High Power, Frequency Tunable, Submillimeter Wave ESR Device Using a Gyrotron as a Radiation Source  

Microsoft Academic Search

ESR device using a submillimeter wave gyrotron as a radiation source and a pulse magnet for high field up to 30 T has been constructed. Our gyrotrons (Gyrotron FU series) were developed as millimeter and submillimeter wave radiation sources and have attractive advantages for ESR spectroscopy, for example, high power and frequency tunability over broad range. The ESR device has

S. Mitsudo; Aripin; T. Shirai; T. Matsuda; T. Kanemaki; T. Idehara

2000-01-01

245

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

SciTech Connect

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

Freeman, R.L.

1996-08-01

246

Unified energy conversion, power systems and power electronics lab  

Microsoft Academic Search

This paper introduces an unified laboratory consisting of power systems, power electronics and energy conversions at Oklahoma State University-Tulsa. It presents more on digital data acquisition (DAQ), and virtual instrumentation (VI), the base of our unified lab. The general design of lab setup is described here, and unique designs of front panels and motor mount are discussed in detail. Some

Seungwon An; Swakshar Ray; Thomas W. Gedra

2002-01-01

247

Innovative power generators for energy harvesting using electroactive polymer artificial muscles  

NASA Astrophysics Data System (ADS)

The type of electroactive polymer known as dielectric elastomers has shown considerable promise for a variety of actuator applications and may be well suited for harvesting energy from environmental sources such as ocean waves or water currents. The high energy density and conversion efficiency of dielectric elastomers can allow for very simple and robust "direct drive" generators. Preliminary energy harvesting generators based on dielectric elastomers have been tested. A generator attached to a rotating waterwheel via a crankshaft produced 35 mJ per revolution in a laboratory test with an actual water flow. A generator that harvests the energy of ocean waves for purposes of supplying power to ocean buoys (such as navigation buoys) was tested at sea for two weeks. This buoy-mounted generator uses a proof-mass to provide the mechanical forces that stretch and contract the dielectric elastomer generator. The generator operated successfully during the sea trials. Wave conditions were very small during this test. Although the device did not produce large amounts of power, it did produce net power output with waves as small as 10 cm peak-to-peak wave height. Both the waterwheel and buoy-mounted generators will be scaled up to produce larger amounts of power. The use of significantly larger amounts of dielectric elastomer material to produce generator modules with outputs in the kilowatt range is being investigated for application to ocean wave power systems.

Chiba, Seiki; Waki, Mikio; Kornbluh, Roy; Pelrine, Ron

2008-05-01

248

Energy-momentum quanta in Fresnel's evanescent wave  

Microsoft Academic Search

Fresnel's theory of the evanescent wave in total reflection entails that the propagation vectork and the momentum quantahk have an imaginary component and, thus, a projection on the reflecting plane that is larger (in units such thatc=1) than the angular frequency? and the energy quantah?. We discuss the ‘tachyon properties’ of these energy-momentum quanta and propose an experimental test using

O. Costa de Beauregard; Ch. Imbert; J. Ricard

1971-01-01

249

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

250

Comparative study of turbines for wave energy conversion  

Microsoft Academic Search

The objective of this paper is to compare the performances of the turbines, which could be used for wave energy conversion\\u000a in the near future, under various irregular wave conditions. The turbines included in the paper are as follows: (a) Wells\\u000a turbine with guide vanes; (b) impulse turbine with self-pitch-controlled guide vanes; (c) impulse turbine with fixed guide\\u000a vanes. In

Hideaki Maeda; Toshiaki Setoguchi; Manabu Takao; Keita Sakurada; Tae-Ho Kim; Kenji Kaneko

2001-01-01

251

Method of, and apparatus for, extracting energy from waves  

SciTech Connect

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

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

1981-11-17

252

Relativistic three-centimeter backward-wave tube with 3 GW pulse power  

NASA Astrophysics Data System (ADS)

In this paper, we present the results of investigations of a uniform three-centimeter relativistic backward-wave tube (BWT) with circular waveguide operating mode E01 with pulse power 3 GW and efficiency about 20%. We have obtained a dependence of the radiation pulse duration on the generated power. We discuss the problems involved in shortening the duration of the microwave pulses in oscillators with high microwave field intensity on the surface of the slow-wave structure.

Gunin, A. V.; Kitsanov, S. A.; Klimov, A. I.; Korovin, S. D.; Pegel', I. V.; Polevin, S. D.; Roitman, A. M.; Rostov, V. V.; Stepchenko, A. S.; Sukhov, M. Yu.

1996-12-01

253

Power waves formulation of oscillation conditions: Avoidance of bifurcation modes in cross-coupled VCO architectures  

Microsoft Academic Search

This paper discusses necessity of power-waves formulation to extend voltage-current oriented approaches based on linear concepts such as admittance\\/impedance operators and transfer-function representations. Importance of multi-physics methodologies, throughout power-waves formulation, for the analysis and design of crystal oscillators is discussed. Interpretation of bifurcation modes in differential cross-coupled VCO architectures in terms of gyrator-like behavior, is proposed. Impact of amplitude level

Sidina Wane; Damienne Bajon

2010-01-01

254

Energy flux of edge waves travelling along a continental shelf  

NASA Astrophysics Data System (ADS)

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

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

255

Arterial wave propagation phenomena, ventricular work, and power dissipation  

Microsoft Academic Search

The effects of wave propagation phenomena, namely global reflection coefficient (?G[?]) and pulse wave velocity (c\\u000a ph), are studied in a model of the coupled left ventricle\\/arterial system. The left ventricle consists of a time-varying elastance,\\u000a while the arterial system is modeled as a single, uniform, elastic tube terminating in a complex load. Manipulation of model\\u000a parameters allowed for the

David S. Berger; John K. J. Li; Abraham Noordergraaf

1995-01-01

256

Analyzing power measurements in pion deuteron absorption at low energies  

NASA Astrophysics Data System (ADS)

As part of an experimental study of the ?NN system, the pion absorption reaction, ?+d-->-->pp, is investigated at low energy. Angular distributions of the vector analyzing power, iT11, are presented for six complementary angle pair coincidences at 65 MeV and five pairs at 25 MeV. There is good agreement with previous measurements, and a significant improvement in uncertainties has been achieved. Results are compared with theoretical predictions based on three different approaches. The best agreement is with a relativistic Faddeev calculation by the Lyon group. Calculations based on the partial wave solutions of Arndt et al. are compared with the data at both energies.

Yeomans, D. M.; Mathie, E. L.; Huber, G. M.; Naqvi, S. I. H.; Persram, D. S.; Pavan, M.; Tacik, R.; Healey, D.; Ottewell, D. F.; Smith, G. R.; Amaudruz, P.

1994-06-01

257

High-energy effective action from scattering of QCD shock waves  

SciTech Connect

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

Ian Balitsky

2005-10-25

258

High-energy effective action from scattering of QCD shock waves  

SciTech Connect

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

Ian Balitsky

2005-07-01

259

High-energy effective action from scattering of QCD shock waves  

SciTech Connect

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

Balitsky, Ian [Physics Department, Old Dominion University, Norfolk, Virginia 23529 (United States); and Theory Group, Jlab, 12000 Jefferson Ave, Newport News, Virginia 23606 (United States)

2005-10-01

260

High-energy effective action from scattering of QCD shock waves  

SciTech Connect

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

Ian Balitsky

2007-01-01

261

High-energy effective action from scattering of QCD shock waves  

SciTech Connect

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

Ian Balitsky

2005-05-15

262

Cyclotron-wave converter for SPS energy transmission system  

NASA Astrophysics Data System (ADS)

The possibility of cyclotron-wave converter (CWC) realization with power level up to 100 kW, output voltage up to 100 kV, efficiency to 85-90 percent and high reliability is presented. The perspectives of CWC application in the SPS ground station are discussed in comparison with rectenna elements based on Schottky-barrier diodes.

Vanke, V. A.; Savvin, V. L.

263

Unified power engineering laboratory for electromechanical energy  

Microsoft Academic Search

Summary form only given. This paper introduces a unified power engineering laboratory capable of various experiments for power systems, power electronics and electromechanical energy conversion. It presents a flexible hardware setup, data acquisition (DAQ), and virtual instrumentation (VI), the base of our unified lab. Some features of virtual instrumentation are shown with real-time phasor diagrams, sequence component analysis, and spectral

T. Gedra; Seungwon An

2004-01-01

264

Renewable Energy. The Power to Choose.  

ERIC Educational Resources Information Center

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

Deudney, Daniel; Flavin, Christopher

265

Waves and energy in random elastic guided media through the stochastic wave finite element method  

NASA Astrophysics Data System (ADS)

Energy propagation in random viscoelastic media is considered in this Letter. The forced response of uncertain waveguide subject to time harmonic loading is treated. This energy model is based on a spectral approach called the "Stochastic Wave Finite Element" (SWFE) method which is detailed in this Letter. Assuming that the random properties are spatially homogeneous in the media, the SWFE is a hybridization of the deterministic wave finite element and a parametric probabilistic approach. The proposed model is applicable in a wide frequency band with reduced time consumption. Numerical examples show the effectiveness of the proposed approach to predict the statistics of kinematic and quadratic variables of guided wave propagation. The results are compared to Monte Carlo simulations.

Ben Souf, M. A.; Bareille, O.; Ichchou, M. N.; Bouchoucha, F.; Haddar, M.

2013-11-01

266

Optimal Power Flow of Multiple Energy Carriers  

Microsoft Academic Search

This paper presents an approach for combined optimization of coupled power flows of different energy infrastructures such as electricity, gas, and district heating systems. A steady state power flow model is presented that includes conversion and transmission of an arbitrary number of energy carriers. The couplings between the different infrastructures are explicitly taken into account based on the new concept

Martin Geidl; Göran Andersson

2007-01-01

267

InGaAs pseudomorphic HEMTs for millimeter wave power applications  

Microsoft Academic Search

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

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

1988-01-01

268

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

SciTech Connect

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

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

2010-03-15

269

Linking multiple relaxation, power-law attenuation, and fractional wave equations.  

PubMed

The acoustic wave attenuation is described by an experimentally established frequency power law in a variety of complex media, e.g., biological tissue, polymers, rocks, and rubber. Recent papers present a variety of acoustical fractional derivative wave equations that have the ability to model power-law attenuation. On the other hand, a multiple relaxation model is widely recognized as a physically based description of the acoustic loss mechanisms as developed by Nachman et al. [J. Acoust. Soc. Am. 88, 1584-1595 (1990)]. Through assumption of a continuum of relaxation mechanisms, each with an effective compressibility described by a distribution related to the Mittag-Leffler function, this paper shows that the wave equation corresponding to the multiple relaxation approach is identical to a given fractional derivative wave equation. This work therefore provides a physically based motivation for use of fractional wave equations in acoustic modeling. PMID:22087931

Näsholm, Sven Peter; Holm, Sverre

2011-11-01

270

A high power Ka band millimeter wave generator with low guiding magnetic field  

SciTech Connect

A slow wave type gigawatt millimeter wave generator is proposed in this paper. In order to increase power capacity, overmoded slow wave structures (SWSs) with larger diameter have been used. Taking advantage of the ''surface wave'' property of overmoded SWSs, the TM{sub 01} mode can be selected to be the operating mode. Calculations have also been carried out to choose a proper low operating magnetic field strength, and it agrees with particle in cell (PIC) simulations. Main structure parameters of the device are optimized by PIC simulations. A typical simulation result is that, at the beam parameters of 600 keV and 5.05 kA, and guiding magnetic field of 0.85 T, a Ka band millimeter wave with an output power of 1.05 GW is generated, yielding a conversion efficiency of about 35%.

Zhu Jun; Shu Ting; Zhang Jun; Li Guolin; Zhang Zehai [College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha, 410073 (China)

2010-08-15

271

Performance of a wave energy device in shallow-water nonlinear waves: part II  

Microsoft Academic Search

This paper continues the work reported in Part I, on a shallow-water device in nondispersive, nonlinear waves. The first objective here is to study a method to control the motion of a bottom-supported, oscillating water column device, for increased energy absorption at a chosen damping level. Also studied in this paper is the effect of nonlinear viscous damping. The efficiencies

Umesh A. Korde

1997-01-01

272

A high-power millimeter-wave sheet beam free-electron laser amplifier  

SciTech Connect

The results of experiments with a short period (9.6 mm) wiggler sheet electron beam (1.0 mm x 2.0 cm) millimeter-wave free electron laser (FEL) amplifier are presented. This FEL amplifier utilized a strong wiggler field for sheet beam confinement in the narrow beam dimension and an offset-pole side-focusing technique for the wide dimension beam confinement. The beam analysis herein includes finite emittance and space-charge effects. High-current beam propagation was achieved as a result of extensive analytical studies and experimental optimization. A design optimization resulted in a low sensitivity to structure errors and beam velocity spread, as well as a low required beam energy. A maximum gain of 24 dB was achieved with a 1-kW injected signal power at 86 GHz, a 450-kV beam voltage, 17-A beam current, 3.8-kG wiggler magnetic field, and a 74-period wiggler length. The maximum gain with a one-watt injected millimeter-wave power was observed to be over 30 dB. The lower gain at higher injection power level indicates that the device has approached saturation. The device was studied over a broad range of experimental parameters. The experimental results have a good agreement with expectations from a one-dimensional simulation code. The successful operation of this device has proven the feasibility of the original concept and demonstrated the advantages of the sheet beam FEL amplifier. The results of the studies will provide guidelines for the future development of sheet beam FEL`s and/or other kinds of sheet beam devices. These devices have fusion application.

Cheng, S.; Destler, W.W.; Granatstein, V.L.; Antonsen, T.M.; Levush, B.; Rodgers, J.; Zhang, Z.X. [Univ. of Maryland, College Park, MD (United States)

1996-06-01

273

Ionospheric modification by chemical releases and high-power radio waves  

SciTech Connect

Ionospheric plasma density irregularities can be produced locally by chemical releases from space vehicles or remotely by a beam of high power radio waves transmitted from the ground. F-region plasma modification occurs by (1) chemically enhancing the electron number density, (2) chemically reducing the electron population, or (3) physically convecting the plasma from one region to another. The three processes (production, loss, and transport) can determine the effectiveness of ionospheric chemical releases and high frequency electromagnetic wave transmissions in subtle and surprising ways. Initially, a chemical release produces a localized change in plasma density and high power radio waves heat the electrons to yield enhanced transport from pressure gradients in the heated region. Subsequent processes, however, can lead to enhanced transport in chemically modified regions and modified reaction rates in the regions affected by high power radio waves.

Bernhardt, P.A.; Scales, W.A.; Keskinen, M.J.; Duncan, L.M.; Rowland, H.L.

1990-05-03

274

Optimization of aperture illumination for radio wave power transmission  

Microsoft Academic Search

Fundamental design indices are presented for a satellite microwave power transmission antenna, with account taken of the electromagnetic environment. The work was performed to quantify the maximum power levels that could be transmitted from a satellite to earth without producing harmful environmental effects. An optimized aperture illumination is calculated to obtain maximized power transmission efficiency with acceptable radiation peaks in

T. Uno; S. Adachi

1984-01-01

275

Out of Sight but Not out of Mind? Public Perceptions of Wave Energy  

Microsoft Academic Search

Public concern about the visual and environmental impacts of renewable-energy projects has been a major factor behind the stalling or rejection of many planning applications for on-shore renewables developments. Siting renewables facilities in off-shore locations would appear to reduce this tension but, as yet, limited research has been conducted on public attitudes to marine renewables—particularly tidal and wave power—to establish

Ian Bailey; Jodie West; Ian Whitehead

2011-01-01

276

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

Microsoft Academic Search

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

Umesh A. Korde

2002-01-01

277

Compact inductive energy storage pulse power system.  

PubMed

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. PMID:22667637

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

2012-05-01

278

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

279

Stopping power for low-energy protons  

Microsoft Academic Search

The stopping power and straggling of energy loss for protons of initial energies 418, 340 and 303 keV have been studied in ethylene, propylene, styrene and their polymers. Employing the inverse stopping power functions, cross sections have been obtained in the energy range 20-400 keV. The existence of a phase effect has been clearly demonstrated. The theoretical stopping cross section

A. K. M. M. Haque; A. Mohammadi; H. Nikjoo

1989-01-01

280

Power sensitivity of vibration energy harvester  

Microsoft Academic Search

This paper deals with a power sensitivity improvement of an electromagnetic vibration energy harvester which generates electrical\\u000a energy from ambient vibrations. The harvester provides an autonomous source of energy for wireless applications, with an expected\\u000a power consumption of several mW, placed in environment excited by ambient mechanical vibrations. An appropriately tuned up\\u000a design of the harvester with adequate sensitivity provides

Zdenek Hadas; Cestmir Ondrusek; Vladislav Singule

2010-01-01

281

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

SciTech Connect

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

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

2010-08-15

282

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

NASA Astrophysics Data System (ADS)

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

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

2010-08-01

283

PRINCIPLES FOR CAPTURE OF ENERGY FROM OCEAN WAVES. PHASE CONTROL AND OPTIMUM OSCILLATION  

Microsoft Academic Search

1. Absorption of waves means generation of waves. A body oscillating in water will produce waves. A big body and a small body may produce equally large waves provided the smaller body oscillates with larger amplitude. This may be utilised for the purpose of wave energy conversion, for instance by a small floating body heaving in response to an incident

J. Falnes

284

Cyclotron Wave Amplification Using Self Generated Pump Power.  

National Technical Information Service (NTIS)

This report describes measurements on an amplifier system consisting of two cascaded Adler tubes with a traveling wave tube (TWT) to amplify the pump signal. The latter was produced by the signal itself in the quadrupole of one of the Adler tubes. By so d...

J. Jaderblom

1966-01-01

285

Wave Power Plant: System Loquist-Gustofsson-Noren.  

National Technical Information Service (NTIS)

A model of a wave plant has been tested. The device consists of a circular buoy, 0.75 m in diameter, equipped with an accelerator - tube 3 to 5 m long. A piston in this tube drives a dc-generator in the buoy. The test results are in good agreement with th...

G. Fredriksson

1979-01-01

286

Constrained package millimeter-wave quasi-optical power combining amplifiers  

Microsoft Academic Search

In the growing field of wireless, microwave and mm-wave there is a constant demand for increasing the frequency of operation and the output power of solid state devices. These requirements are combined with the need to reduce the cost of the circuits for both commercial and defense applications. A possible way to meet these requirements is to combine the power

Toni Georgiev Ivanov

1997-01-01

287

Design of a sine-wave constant current source switching power supply for laser applications  

Microsoft Academic Search

The design and performance of a simple resonant tank circuit, sine-wave, constant current source switching power supply are described. On the basis of a simplified circuit model, the main equations describing the operation of the power supply when the load voltage varies with time are evaluated and the general design formulae are presented. A comparison is made between the results

I. V. Chaltakov

1988-01-01

288

Power scaling of continuous-wave adaptive gain-grating laser resonators  

Microsoft Academic Search

We demonstrate a power-scaling strategy in a continuous-wave adaptive phase-conjugate oscillator power amplifier (PCO-PA) system that actively corrects, via phase-conjugation, for thermally induced phase-distortions introduced by a power-amplifier (PA) placed in the output arm of the phase conjugate oscillator (PCO). Phase-conjugation is achieved by saturable gain four-wave mixing in a PCO Nd:YVO4 amplifier. Single-longitudinal mode phase-conjugate (PC) outputs of almost

Jason M. Hendricks; David I. Hillier; Stephen J. Barrington; David P. Shepherd; Robert W. Eason; Michael J. Damzen; Ara Minassian; Benjamin Thompson

2002-01-01

289

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.

290

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

291

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.

292

A high power, high efficiency millimeter-wave pseudomorphic HEMT  

Microsoft Academic Search

A pseudomorphic HEMT (high electron mobility transistor) with record output power and high efficiency at 44 GHz has been developed. The 0.15 ?m gate-length, 900 ?m gate-width device generates 500 to 700 mW of output power with power-added efficiencies ranging from 22 to 30%. Moreover, the devices are producible: DC yields for these large gate-width HEMTs are 50-80% and uniformity

P. M. Smith; D. W. Ferguson; W. F. Kopp; P. C. Chao; W. Hu; P. Ho; J. M. Ballingall

1991-01-01

293

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

PubMed

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

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

2012-11-01

294

Experimental statistical energy analysis of coupled plates with wave conversion at the junction  

Microsoft Academic Search

Coupling loss factors for bending wave transmission between coupled plates can be determined using experimental statistical energy analysis. However, some types of plate junctions introduce significant wave conversion such that the assumption of a statistical energy analysis (SEA) system that supports only bending waves is no longer appropriate. Three methods have been assessed to identify the existence of wave conversion

C. Hopkins

2009-01-01

295

Optimum design and control of anchored wave energy generators  

SciTech Connect

Discussed is the development of design data and strategies for optimizing the performance of wave energy generators. Rectangular buoys are considered for illustration. The buoy dimensions necessary for maximizing the conversion efficiency while minimizing its size for a particular ocean condition are evaluated. 12 refs.

Abuelnaga, A.; Seireg, A.

1982-03-01

296

Dynamic Theory: some shock wave and energy implications  

SciTech Connect

The Dynamic Theory, a unifying five-dimensional theory of space, time, and matter, is examined. The theory predicts an observed discrepancy between shock wave viscosity measurements at low and high pressures in aluminum, a limiting mass-to-energy conversion rate consistent with the available data, and reduced pressures in electromagneticaly contained controlled-fusion plasmas.

Williams, P.E.

1981-02-01

297

Carrier-wave telephony over power lines- early history  

Microsoft Academic Search

In this paper we focus on the early history of using power lines for voice communications, beginning in 1918 and carrying the story forward to the early 1930s, when telephony using power lines had essentially established itself as a mature technology worldwide.

Mischa Schwartz; Charles Batchelor

2007-01-01

298

Energy analysis of the solar power satellite.  

PubMed

The energy requirements to build and operate the proposed Solar Power Satellite are evaluated and compared with the energy it produces. Because the technology is so speculative, uncertainty is explicitly accounted for. For a proposed 10-gigawatt satellite system, the energy ratio, defined as the electrical energy produced divided by the primary nonrenewable energy required over the lifetime of the system, is of order 2, where a ratio of 1 indicates the energy breakeven point. This is significantly below the energy ratio of today's electricity technologies such as light-water nuclear or coal-fired electric plants. PMID:17758765

Herendeen, R A; Kary, T; Rebitzer, J

1979-08-01

299

Energy of tsunami waves generated by bottom motion  

Microsoft Academic Search

In the vast literature on tsunami research, few articles have been devoted to\\u000aenergy issues. A theoretical investigation on the energy of waves generated by\\u000abottom motion is performed here. We start with the full incompressible Euler\\u000aequations in the presence of a free surface and derive both dispersive and\\u000anon-dispersive shallow-water equations with an energy equation. It is shown

Denys Dutykh; Frédéric Dias

2009-01-01

300

Energy-Dependent Potential and Normalization of Wave Function  

NASA Astrophysics Data System (ADS)

The problem of normalization related to energy-dependent potentials is examined in the context of the path integral approach, and a justification is given. As examples, the harmonic oscillator and the hydrogen atom (radial) where, respectively the frequency and the Coulomb's constant depend on energy, are considered and their propagators determined. From their spectral decomposition, we have found that the wave functions extracted are correctly normalized.

Benchikha, A.; Chetouani, L.

2013-06-01

301

MAGNETOACOUSTIC WAVE ENERGY FROM NUMERICAL SIMULATIONS OF AN OBSERVED SUNSPOT UMBRA  

SciTech Connect

We aim at reproducing the height dependence of sunspot wave signatures obtained from spectropolarimetric observations through three-dimensional MHD numerical simulations. A magnetostatic sunspot model based on the properties of the observed sunspot is constructed and perturbed at the photosphere, introducing the fluctuations measured with the Si I {lambda}10827 line. The results of the simulations are compared with the oscillations observed simultaneously at different heights from the He I {lambda}10830 line, the Ca II H core, and the Fe I blends in the wings of the Ca II H line. The simulations show a remarkable agreement with the observations. They reproduce the velocity maps and power spectra at the formation heights of the observed lines, as well as the phase and amplification spectra between several pairs of lines. We find that the stronger shocks at the chromosphere are accompanied with a delay between the observed signal and the simulated one at the corresponding height, indicating that shocks shift the formation height of the chromospheric lines to higher layers. Since the simulated wave propagation matches very well the properties of the observed one, we are able to use the numerical calculations to quantify the energy contribution of the magnetoacoustic waves to the chromospheric heating in sunspots. Our findings indicate that the energy supplied by these waves is too low to balance the chromospheric radiative losses. The energy contained at the formation height of the lowermost Si I {lambda}10827 line in the form of slow magnetoacoustic waves is already insufficient to heat the higher layers, and the acoustic energy which reaches the chromosphere is around 3-9 times lower than the required amount of energy. The contribution of the magnetic energy is even lower.

Felipe, T.; Khomenko, E.; Collados, M., E-mail: tobias@iac.es [Instituto de Astrofisica de Canarias, 38205, C/Via Lactea, s/n, La Laguna, Tenerife (Spain)

2011-07-01

302

Correlations between ULF wave power, solar wind speed, and relativistic electron flux in the magnetosphere: solar cycle dependence  

NASA Astrophysics Data System (ADS)

We present results from a rank order correlation coefficient (ROCC) analysis between ground-based 1-10mHz ultra-low frequency (ULF) wave power, upstream solar wind speed (vSW), and MeV electron flux across the outer radiation belt. We use data spanning a complete solar cycle (1990-2001) from ground magnetometers from the SAMNET and IMAGE arrays, and MeV electron data from the Los Alamos spacecraft at geosynchronous orbit (GEO) and from a HEO spacecraft at L=5.5 and 4.5. We find a very high correlation between ULF wave power and vSW at all local times and on all L-shells between L=3.1 and 6.6. Very strong cross-L-shell ULF power coherence is maintained throughout the solar cycle, although the efficiency of vSW in driving a given ULF power response is solar cycle dependent. Peak ULF power and peak ROCC (~0.75) are observed during the declining phase of the solar cycle around 1994-1995, with smaller localised peaks in these parameters occurring during slower average vSW conditions close to solar maximum in 2000. There is also a strong correlation of both vSW and ULF power with MeV electron flux, these correlations being more strongly dependent on solar cycle phase. The vSW and ULF power correlations with MeV electron flux peak during the late declining phase of the solar cycle, when the radiation belts are most intense. Our results confirm that radiation belt flux demonstrates extremely strong global cross-L-shell coherence throughout the solar cycle. The ROCC between vSW or ULF power and MeV electron flux demonstrate a clear and systematic time lag following the peak in either vSW or ULF power. Electron fluxes respond first at GEO (lag ~2 days), before subsequently peaking at lower L-shells. Importantly, our results indicate that vSW-correlated MeV electron acceleration processes operate by inwards radial transport. The correlation between ULF power and MeV energy electron flux further suggests that ULF waves could be causally responsible via ULF wave enhanced radial diffusion.

Mann, I. R.; O'Brien, T. P.; Milling, D. K.

2004-01-01

303

Power and Energy Strategy White Paper.  

National Technical Information Service (NTIS)

Power and energy grow ever more important to our military capabilities; they enable every system that supports Soldier and unit performance, from mobility and weapons systems to surveillance and communications -- not to mention simple heating and cooling....

P. Schihl P. E. Roege R. Kirker

2010-01-01

304

Teaching About Energy: Power of a Student  

NSDL National Science Digital Library

This student activity is designed to help students understand the concept of power. The energy required to climb stairs, and the rate at which students can do this, illustrates this concept. The energy requirements for other common activities are given to help students calculate their energy needs. Included are notes for instructors wishing to use this material. This activity is part of a PTRA manual on Energy.

Roeder, John

2006-01-17

305

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: a 3-GHz, 10-GW microwave beam from a proposed satellite power station and 1-MW and 3-MW beams of 15-MHz radio waves launched by the Arecibo antenna. The most dramatic heating

F. W. Perkins; R. G. Roble

1978-01-01

306

A high-power intrawell radiator of shear waves for coherent seismoacoustics  

Microsoft Academic Search

A brief review of investigations in the field of coherent seismoacoustics is presented, and the general requirements for seismoacoustic\\u000a wave radiators intended for solving problems of remote sounding are formulated. The principle of operation of a novel high-power\\u000a radiator created at the Institute of Applied Physics, Russian Academy of Sciences, for generating low-frequency seismic waves\\u000a is described, and the results

V. S. Averbakh; V. V. Artel’nyi; B. N. Bogolyubov; A. L. Virovlyansky; A. I. Malekhanov; A. P. Maryshev; V. I. Talanov

2005-01-01

307

Energy storage for hybrid remote power systems.  

National Technical Information Service (NTIS)

Energy storage can be a cost-effective component of hybrid remote power systems. Storage serves the special role of taking advantage of intermittent renewable power sources. Traditionally this role has been played by lead-acid batteries, which have high l...

W. Isherwood

1998-01-01

308

Direct energy conversion for fusion power  

Microsoft Academic Search

The potential importance of direct energy conversion to the long-term development of fusion power is discussed with stress on the possibility of alleviating waste heat problems. This is envisioned to be crucial for any central power station in the 21st century. Two approaches, direct collection and magnetic expansion, are reviewed. While other techniques may be possible, none have received sufficient

G. H. Miley

1980-01-01

309

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

310

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

311

Wave-powered desalination: resource assessment and review of technology  

Microsoft Academic Search

The growing scarcity of freshwater is driving the implementation of desalination on an increasingly large scale. However, the energy required to run desalination plants remains a drawback. The idea of using renewable energy sources is fundamentally attractive and many studies have been done in this area, mostly relating to solar or wind energy. In contrast, this study focuses on the

P. A. Davies

2005-01-01

312

Comparison of chorus wave power during CIR versus CME-driven geomagnetic storms  

NASA Astrophysics Data System (ADS)

One of the major outstanding scientific problems in the field of heliophysics is understanding and quantifying the dominant source and loss processes that contribute to the variability of relativistic electron populations in the Earth's outer radiation belt. It is known that the dynamics of the outer belt is highly dependent on the driving solar wind conditions during and in the aftermath of geomagnetic storms. For example, geomagnetic storms driven by corotating interaction regions (CIRs) and the following high speed stream (HSS) are particularly efficient at coupling energy into the magnetosphere. Despite the fact that CIR/HSS-driven storms have on average a weaker Dst signature than storms driven by coronal mass ejections (CMEs), these storms typically result in significant outer belt flux enhancements. One process that is believed to play a major role in the evolution of the outer belt is cyclotron-resonant wave particle interactions involving whistler-mode chorus emissions. Chorus interactions can result in the precipitative loss of electrons over a wide range of energy as well as the acceleration of seed electrons (10's to 100's of keV) up to energies of an MeV or greater. Progress in quantifying the role of chorus in radiation belt dynamics requires knowledge of how the chorus wave power varies with time and space as a function of solar wind and magnetospheric conditions. While in situ measurements of chorus are relatively sparse during solar cycle 23, a large database of ground-based ELF/VLF observations from Antarctica exist for this period. Here we examine the variation of chorus activity observed on the ground during a set of geomagnetic storms from 2000 to 2010. We analyze data from Palmer Station, Antarctica (?=-50o) and South Pole Station, Antarctica (?=-74o) thus covering waves generated in the inner magnetosphere as well as in the dayside outer magnetosphere. We explore differences in the intensity, duration and spectral extent of chorus between CIR/HSS-driven storms and CME-driven storms, and we put the results in the context of the global magnetospheric response such as differences in substorm activity and plasmasheet density and temperature.

Spasojevic, M.; Golden, D. I.

2011-12-01

313

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

314

Increasing power and energy in Amonix solar power plants  

Microsoft Academic Search

Large-scale CPV power plants are expected to deliver the high energy production and low electricity cost that will allow PV to become a substantial portion of the electrical grid supply. High concentration minimizes the semiconductor material costs. Dual-axis tracking delivers higher capacity factors and provides a better match to electricity demand. In order to prove the net cost benefits, however,

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

2011-01-01

315

Correlation of Littoral Transport with Wave Energy Along Shores of New York and New Jersey.  

National Technical Information Service (NTIS)

Shows the results of an office study which correlated field measurements of net littoral transport with the average net alongshore component of wave energy. Employs a survey attempt toward a 'wave energy - littoral transport' correlation for a 500-mile st...

J. C. Fairchild

1966-01-01

316

Radiation of inertial kinetic energy as near-inertial waves forced by tropical Pacific Easterly waves  

NASA Astrophysics Data System (ADS)

Easterly waves (EW) are low level tropical atmospheric disturbances able to resonantly force strong mixed layer inertial currents. Using data from two Tropical Atmosphere Ocean/Eastern Pacific Investigation of Climate Processes (TAO/EPIC) buoys located along 95°W and a multiparameterization one-dimensional turbulence model, we examine how the EW-forced surface inertial kinetic energy (IKE) loss is partitioned between turbulent dissipation and near-inertial wave (NIW) radiation. Several EW-forcing events are individually simulated with a version of the General Ocean Turbulence Model modified to include a linear damping coefficient to account for the NIW radiation energy sink. The kinetic energy budget of these simulations shows that NIW radiation accounted for typically 50-60% of the IKE loss and in some cases up to 80%. These empirically derived estimates of the contribution of the radiated NIWs to the loss of wind-induced surface IKE are substantially higher than recently published numerical estimates. Furthermore, the results indicate that the vertical NIW energy flux increases linearly with the wind input of IKE, an easily obtained quantity. The NIW vertical energy flux estimated for a single near-resonant event is comparable to extreme north Pacific wintertime-averaged fluxes, indicating the existence of important episodic sources of near-inertial energy available for mixing within and below the thermocline in the tropical region.

Soares, S. M.; Richards, K. J.

2013-05-01

317

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

318

Unified power engineering laboratory for electromechanical energy conversion, power electronics, and power systems  

Microsoft Academic Search

This paper introduces a unified power engineering laboratory capable of various experiments for power systems, power electronics, and electromechanical energy conversion. It presents a flexible hardware setup, data acquisition (DAQ), and virtual instrumentation (VI). Some features of virtual instrumentation are shown with real-time phasor diagrams, sequence component analysis, and spectral analysis of AC data. We describe the general design of

Thomas W. Gedra; Seungwon An; Q. H. Arsalan; S. Ray

2004-01-01

319

Dam-Atoll for concentration and conversion of ocean wave energy  

SciTech Connect

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 could provide operational systems in the latter part of this decade.

Higgins, T.P.; Sherburne, C.P.

1981-01-01

320

Study on Conversion from Natural Energy of Waves to Mechanical Energy.  

National Technical Information Service (NTIS)

The object of this study is to install a practical wave power generating test plant on the real sea area for the demonstration test of the power generation; a candidate plant site was selected on the coast of Iriomotejima, Okinawa Prefecture; natural and ...

S. Takezawa K. Sugahara

1984-01-01

321

Energy transport in weakly nonlinear wave systems with narrow frequency band excitation.  

PubMed

A novel discrete model (D model) is presented describing nonlinear wave interactions in systems with small and moderate nonlinearity under narrow frequency band excitation. It integrates in a single theoretical frame two mechanisms of energy transport between modes, namely, intermittency and energy cascade, and gives the conditions under which each regime will take place. Conditions for the formation of a cascade, cascade direction, conditions for cascade termination, etc., are given and depend strongly on the choice of excitation parameters. The energy spectra of a cascade may be computed, yielding discrete and continuous energy spectra. The model does not require statistical assumptions, as all effects are derived from the interaction of distinct modes. In the example given-surface water waves with dispersion function ?(2)=gk and small nonlinearity-the D model predicts asymmetrical growth of side-bands for Benjamin-Feir instability, while the transition from discrete to continuous energy spectrum, excitation parameters properly chosen, yields the saturated Phillips' power spectrum ~g(2)?(-5). The D model can be applied to the experimental and theoretical study of numerous wave systems appearing in hydrodynamics, nonlinear optics, electrodynamics, plasma, convection theory, etc. PMID:23214551

Kartashova, Elena

2012-10-17

322

Stabilized high-power laser system for the gravitational wave detector advanced LIGO.  

PubMed

An ultra-stable, high-power cw Nd:YAG laser system, developed for the ground-based gravitational wave detector Advanced LIGO (Laser Interferometer Gravitational-Wave Observatory), was comprehensively characterized. Laser power, frequency, beam pointing and beam quality were simultaneously stabilized using different active and passive schemes. The output beam, the performance of the stabilization, and the cross-coupling between different stabilization feedback control loops were characterized and found to fulfill most design requirements. The employed stabilization schemes and the achieved performance are of relevance to many high-precision optical experiments. PMID:22565688

Kwee, P; Bogan, C; Danzmann, K; Frede, M; Kim, H; King, P; Pöld, J; Puncken, O; Savage, R L; Seifert, F; Wessels, P; Winkelmann, L; Willke, B

2012-05-01

323

Probing alpha-particle wave functions by (d,alpha) tensor analyzing powers  

Microsoft Academic Search

Components of alpha-particle wave functions corresponding to d-d configurations are used to predict analyzing powers in the (d,alpha) reaction. Tensor analyzing powers, especially Axx, are shown to clearly distinguish between wave functions generated by different realistic nucleon-nucleon interactions. Data for the 58Ni(d,alpha)56Co reaction to the 7+ stretched-nucleon-orbital state at 2.283-MeV excitation in 56Co, measured with 22-MeV deuterons, are compared to

E. R. Crosson; R. K. Das; S. K. Lemieux; E. J. Ludwig; W. J. Thompson; M. Bisenberger; R. Hertenberger; D. Hofer; H. Kader; P. Schiemenz; G. Graw; A. M. Eiró; F. D. Santos

1992-01-01

324

Energy of nonlinear internal waves in the South China Sea  

NASA Astrophysics Data System (ADS)

Four sets of ADCP measurements were taken in the South China Sea (SCS); these results were combined with previous satellite observations and internal-tide numerical model results. Analysis suggests that strong internal tides are generated in Luzon Strait, propagate as a narrow tidal beam into the SCS, are amplified by the shoaling continental slope near TungSha Island, become nonlinear, and evolve into high-frequency nonlinear internal waves (NIW). Internal waves in the SCS have geographically distinct characteristics. (1) West of Luzon Strait the total internal wave energy (Eiw) is 10 × that predicted by Garrett-Munk spectra (EGM) (Levine, 2002). There is no sign of NIW. (2) Near TungSha Island Eiw = 13 × EGM. Strong nonlinear and high-harmonic tides are present. Repetitive trains of large-amplitude NIW appear primarily at a semidiurnal periodicity with their amplitudes modulated at a fortnightly tidal cycle. The rms vertical velocity of NIW shows a clear spring-neap tidal cycle and is linearly proportional to the barotropic tidal height in Luzon Strait with a 1.85-day time lag, consistent with the travel time of internal tides from Luzon Strait to TungSha Island. (3) At the northern SCS shelfbreak Eiw = 4 × EGM. Single depression waves are found, but no multiple-waves packets are evident. (4) On the continental shelf Eiw = 2 × EGM. Both depression and elevation NIW exist.

Lien, R.-C.; Tang, T. Y.; Chang, M. H.; D'Asaro, E. A.

2005-03-01

325

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.

326

Power law scaling for rotational energy transfer  

Microsoft Academic Search

We have applied a new scaling law to several sets of rotational energy transfer cross sections. The new law asserts that the square of the T-matrix depends on the amount of energy transferred as a power law. Two different kinds of angular momentum statistics are assumed, one corresponding to mj being conserved and the other corresponding to mj being completely

David E. Pritchard; Neil Smith; Richard D. Driver; Timothy A. Brunner

1979-01-01

327

A digital controlled energy scavenger power converter  

Microsoft Academic Search

This work proposes an autonomous energy scavenger battery-free switching power supply. A piezoelectric transducer is used to get electric energy from a mechanical vibrating source. Piezoelectric device has been modelled by means of its equivalent electric resonant model. All system has been designed and then simulated at system level by means of SystemC-WMS environment.

R. d'Aparo; S. Orcioni; M. Conti

2009-01-01

328

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

329

Nuclear power, coal, and energy conservation  

Microsoft Academic Search

A programming model is used to explore options by which the U.S. may realistically move from its dependence on oil and gas to a more diversified energy economy based on nuclear power and\\/or coal. Supply options considered are: direct combustion of coal; conversion of coal to synthetic fuels; petroleum, natural gas, and oil shale resources; nuclear energy from light water

P. L. Auer; A. S. Manne; O. S. Yu

1976-01-01

330

Blast shock wave mitigation using the hydraulic energy redirection and release technology.  

PubMed

A hydraulic energy redirection and release technology has been developed for mitigating the effects of blast shock waves on protected objects. The technology employs a liquid-filled plastic tubing as a blast overpressure transformer to transfer kinetic energy of blast shock waves into hydraulic energy in the plastic tubings. The hydraulic energy is redirected through the plastic tubings to the openings at the lower ends, and then is quickly released with the liquid flowing out through the openings. The samples of the specifically designed body armor in which the liquid-filled plastic tubings were installed vertically as the outer layer of the body armor were tested. The blast test results demonstrated that blast overpressure behind the body armor samples was remarkably reduced by 97% in 0.2 msec after the liquid flowed out of its appropriate volume through the openings. The results also suggested that a volumetric liquid surge might be created when kinetic energy of blast shock wave was transferred into hydraulic energy to cause a rapid physical movement or displacement of the liquid. The volumetric liquid surge has a strong destructive power, and can cause a noncontact, remote injury in humans (such as blast-induced traumatic brain injury and post-traumatic stress disorder) if it is created in cardiovascular system. The hydraulic energy redirection and release technology can successfully mitigate blast shock waves from the outer surface of the body armor. It should be further explored as an innovative approach to effectively protect against blast threats to civilian and military personnel. PMID:22745740

Chen, Yun; Huang, Wei; Constantini, Shlomi

2012-06-20

331

Shock-Wave and Material Properties Experiments Using the Los Alamos Atlas Pulsed Power System  

NASA Astrophysics Data System (ADS)

The Atlas facility built by Los Alamos is the world's first and only laboratory pulsed power system designed specifically to provide capability for shock-wave physics, materials properties, instability, and hydrodynamics experiments in converging geometry. Constructed in 2000 and commissioned in August 2001, Atlas completed its first year of physics experiments in October 2002, using ultra high precision magnetically imploded, cylindrical liners to reliably and reproducibly convert electrical energy to hydrodynamic energy in targets whose volume is many cubic centimeters. Multi-view (transverse and axial) radiography, laser-illuminated shadowgraphy, and VISAR measurements of liner and target surface motion, in addition to electrical diagnostics, provide a detailed description of the behavior of the experimental package. In the first year material damage and failure experiments, dynamic friction experiments, and a family of converging shock experiments were conducted in addition to a detailed series of liner implosion characterization experiments. These experiments will continue and additional series to evaluate material strength at very high rates of strain, ejecta formation from surfaces, and instability growth at interfaces will be added in the future.

Reinovsky, R. E.; Anderson, W. E.; Atchison, W. L.; Faehl, R. J.; Keinigs, R. K.; Lindemuth, I. R.; Thompson, M. C.; Taylor, A.

2004-07-01

332

High power, high efficiency 32 GHz space traveling wave tube  

Microsoft Academic Search

Boeing Electron Dynamic Devices, Inc. in collaboration with NASA Glenn Research Center, has demonstrated 100 W CW and 60% overall efficiency at 32 GHz in a TWT designed for deep space communications applications. Additionally, the TWT is designed to allow for variable output power levels, from 50 to 150 W, depending on mission requirements. The Boeing 999H is a helix

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

2004-01-01

333

High efficiency, diode pumped Nd:YAG ceramics slab laser with 230 W continuous-wave output power.  

PubMed

Diode pumped zig-zag slab lasers are widely adopted for continuous-wave high power or pulsed high energy applications. Recently [J. Eur. Opt. Soc.-Rapid 6, 11041 (2011)] we started to investigate a new thin slab format in which pumping radiation input is obtained through the thin lateral faces (edge pumping) and the beam propagation takes place bouncing on these same lateral faces ("edge zig-zag"). We report on the optimized operation of a ceramic Nd:YAG laser, based on this geometry, extracting 230 W at a 43% output power to diode power conversion efficiency. Thorough investigation of the thermal lens effect allows us to analyze the optical cavity and thus to define the main aspects limiting the present laser configuration. PMID:22722302

Lapucci, Antonio; Ciofini, Marco; Vannoni, Maurizo; Sordini, Andrea

2012-06-20

334

The commercial advancement of 16 MW offshore wave power generation technologies in the southwest of the UK  

Microsoft Academic Search

This paper presents the work carried out to develop the Wave Hub project off the coast of southwest of the UK, which represents the world's first large-scale wave- energy farm. Four companies have been chosen to deploy their own particular wave-energy converters. These include the Pelamis, the Overtopping Device, the Multiple Point Absorber System, and the Oscillating Water Column. The

Tarek Ahmed; Katsumi Nishida; Mutsuo Nakaoka

2011-01-01

335

PIEZOELECTRIC MICRO POWER GENERATOR FOR ENERGY HARVESTING  

Microsoft Academic Search

A thin film lead zirconate titanate Pb(Zr,Ti)O3 (PZT), power generating device is developed. It is designed to resonate at specific vibrational frequencies from an ambient, vibrational energy source, thereby creating electrical energy via the piezoelectric effect. The energy harvesting device uses the piezoelectric d33 mode and is fabricated with three mask steps. Our cantilever device was designed to have a

R. Sood; Y. B. Jeon; S. G. Kim

336

An Energy Management Strategy for a Wind Power Plant Based on Energy Storage and Wind Power Prediction  

Microsoft Academic Search

Wind energy is the most common and fastest-growing application of renewable energy in power systems. Wind power generation is an intermittent and unpredictable energy, therefore power system operators have to face some difficulties such as stability, reliability, power quality, etc. Wind forecast and energy storage techniques are used for system reliability, stability, and increasing the penetration level of wind energy.

B. Ya?citekin; Ö. Güler; Ü. Çali

2012-01-01

337

Classification of Australian Clastic Coastal Depositional Environments Based Upon a Quantitative Analysis of Wave, Tidal, and River Power  

Microsoft Academic Search

A statistical assessment of wave, tide, and river power was carried out using a database of 721 Australian clastic coastal deposi- tional environments to test whether their geomorphology could be pre- dicted from numerical values. The geomorphic classification of each environment (wave- and tide-dominated deltas, wave- and tide-domi- nated estuaries, lagoons, strand plains, and tidal flats) was established independently from

P. T. Harris; A. D. Heap; S. M. Bryce; R. Porter-Smith; D. A. Ryan; D. T. Heggie

2002-01-01

338

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

339

Excitation of artificial airglow by high power radio waves from the SURA ionospheric heating facility  

SciTech Connect

The SURA facility for generation of high power radio waves, located near the village of Vasil'sursk USSR, operates between 4.5 and 9.0 MHz and has a maximum effective radiated power (ERP) of 300 MW. Nonlinear interactions between the HF radio waves and F-layer plasma occur near the electromagnetic wave reflection point. Energetic electrons are accelerated out of the interaction regions by the electrostatic waves. Ambient oxygen atoms collisionally excited by these suprathermal electrons yield enhanced airglow. Low-light-level, optical measurements were made at SURA during September 1990. Images of enhanced red-line (630 nm) emissions were recorded during radio wave transmissions at 4.786, 5.455, and 5.828 MHz. The antenna radiation pattern, ionospheric irregularities, and the magnetic field orientation affected the shape of the observed airglow structures. The airglow clouds drifted across the night sky, disappeared, and reformed at the zenith of the antenna array. This has been interpreted in terms of radio beam refraction in drifting plasma irregularities and bifurcation when the beam is split between two density cavities. Subject to clear skies, the authors experience indicates that the low-light-level-imaging technique is a reliable method to study large scale irregularities and electron acceleration with high-power HF transmitting facilities.

Bernhardt, P.A.; Scales, W.A. (Naval Research Lab., Washington, DC (United States)); Grach, S.M.; Keroshtin, A.N.; Kotik, D.S.; Polyakov, S.V. (Radiophysical Research Inst., Novgorod (USSR))

1991-08-01

340

Wave energy in surface layers for energy-based damage evaluation  

Microsoft Academic Search

Seismic wave energy in surface layers is calculated based on vertical array records at four sites during the 1995 Hyogo-ken Nambu earthquake by assuming vertical propagation of SH waves. The upward energy generally tends to decrease as it goes up from the base layer to the ground surface particularly in soft soil sites. Theoretical study on 1D multi-layers model to

Takaji Kokusho; Ryuichi Motoyama; Hiroshi Motoyama

2007-01-01

341

Dispersion of capillary-gravity waves: a derivation based on conservation of energy  

NASA Astrophysics Data System (ADS)

Waves on fluids provide an excellent context for introducing some important topics in fluid dynamics. In this paper we first discuss the behaviour of standing surface waves and present their special properties. Next the dispersion relation of surface waves is derived in a novel way by applying the conservation of energy to the case of standing waves.

Behroozi, F.; Podolefsky, N.

2001-05-01

342

On the energy of the wind stress required to produce internal and inertial waves  

Microsoft Academic Search

In a rectangular channel wind-produced internal and inertial waves are studied. The energy of the wind field within the internal wave range is approximated by a single wave having a period of 10 hours. If the wind field is smooth in the basin, the produced current distribution is also smooth. In order to produce internal waves the Fourier amplitudes of

W. Krauss

1978-01-01

343

Energy loss and set-up due to breaking random waves  

Microsoft Academic Search

A description is given of a model developed for the prediction of the dissipation of energy in random waves breaking on a beach. The dissipation rate per breaking wave is estimated from that in a bore of corresponding height, while the probability of occurrence of breaking waves is estimated on the basis of a wave height distribution with an upper

J. A. Battjes; J. P. F. M. Janssen

1978-01-01

344

A permanent magnet tubular linear generator for wave energy conversion  

NASA Astrophysics Data System (ADS)

A novel three-phase permanent magnet tubular linear generator (PMTLG) with Halbach array is proposed for the sea wave energy conversion. Non-linear axi-symmetrical finite element method (FEM) is implemented to calculate the magnetic fields along air-gap for different Halbach arrays of PMTLGs. The PMTLG characteristics are analyzed and the simulation results are validated by the experiment. An assistant tooth is implemented to greatly minimize the end and cogging effects which cause the oscillatory detent force.

Yu, Haitao; Liu, Chunyuan; Yuan, Bang; Hu, Minqiang; Huang, Lei; Zhou, Shigui

2012-04-01

345

Generation and detection of millimeter-wave optical signals for use in power-combining arrays  

Microsoft Academic Search

Optical distribution of millimeter-wave signals is an attractive technology for a number of applications. The feeding of antenna arrays and the distribution of signals in wireless communication systems both stand to benefit from the low power loss, low weight and size, and immunity from electromagnetic interference and crosstalk provided by optical fiber. This thesis presents results for a 60-GHz power-combining

Andrew Charles Davidson

1997-01-01

346

Nonlinear Energy Balance Model of Particle Acceleration by Parallel Shock Waves  

NASA Astrophysics Data System (ADS)

A new theoretical/numerical model of particles acceleration by quasi-parallel shocks is developed and results of numerical analysis are discussed. The model assumes that resonant wave--particle interaction is the most important physical mechanisms relevant to motion and acceleration of particles as well as to excitation and dumping of waves. The treatment of plasma and waves is self-consistent and time dependent. The model uses conservation laws and resonance conditions to find where waves will be generated or dumped and hence particles will be pitch--angle scattered. Since the total distribution function (for bulk plasma and high energy tail) is included in the model, no any special bootstrap or termination assumptions are required (neither introduction of separate population of seed particles nor some ad-hoc escape rate of accelerated particles are needed). The preliminary results show not only remarkable agreement with diffusive shock acceleration (DSA) models in prediction of power spectra for accelerated particles in upstream region but also reveal presence of spectral break in high energy part of the spectra. The role of the second order Fermi acceleration at the initial stage of acceleration is discussed.

Shevchenko, V. I.; Galinsky, V. L.

2007-12-01

347

Excitation of guided ELF-VLF waves through modification of the F2 ionospheric layer by high-power radio waves  

NASA Astrophysics Data System (ADS)

The possibility of controlled excitation of ELF-VLF electromagnetic waves through modification of the F2 ionospheric layer by high-power high-frequency emission is demonstrated in a natural experiment by using the Sura midlatitude heating facility. The excited low-frequency waves can be used to explore the near-Earth space and stimulate the excitation of a magnetospheric maser.

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

2012-03-01

348

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

Microsoft Academic Search

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

Ali Esmaili; Adel Nasiri

2011-01-01

349

Power supply noise investigation of a multilayered IC package: full wave simulation and model validation  

Microsoft Academic Search

The present paper investigates the power supply noise in multilayered IC packages and analyzes the effect of shorting vias. A full wave code, based on the Finite Integration Technique (FIT), is used for the numerical simulations and it is validated by means of measurements. Furthermore two different solvers are employed to verify the accuracy of the proposed model: time domain

A. C. Scogna; C. Ritota

2007-01-01

350

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

NASA Astrophysics Data System (ADS)

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

Thomassen, K. I.

351

Space traveling wave tube amplifiers with on-orbit flexible saturated output power  

Microsoft Academic Search

This paper describes several approaches to achieving adjustable power output from a traveling wave tube amplifier. It can be adjusted in flight for maximum flexibility in matching the amplifier capability to the applicationpsilas need. The efficiency can be maximized without changing the hardware.

Thomas K. Phelps; John D. McDowell; William L. Menninger

2008-01-01

352

P2J-3 Axial Power Flow Distribution of Ultrasonic Guided Waves in Composite Pipes  

Microsoft Academic Search

This paper describes a preliminary investigation of the distribution of axial power flow amplitude of longitudinal guided waves in composite pipes. The dispersion characteristics were computed on the assumption that the frequencies are real and the wavenumbers are complex numbers. The optimal location, optimal mode and its frequency-thickness products (fd) of testing were chosen according to the APF. The results

Dean Ta; Weiqi Wang; L. H. Le

2006-01-01

353

Research in the Field of Propagation of High Power Waves in Ionized Media.  

National Technical Information Service (NTIS)

In this report a survey is given of the research in the field of propagation of high power radio waves in ionized media, and allied fields, carried out by the staff of the Research Laboratory of Electronics 1960-1964. The investigations reported cover suc...

O. E. H. Rydbeck

1964-01-01

354

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

SciTech Connect

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

Thomassen, K.I.

1987-01-01

355

MBE grown selective recess structures for microwave and millimeter-wave power PHEMTs  

Microsoft Academic Search

Two molecular beam epitaxy (MBE) based, single and double selective gate recess structures have been developed to provide superior and high-yield power pseudomorphic high electron mobility transistor (PHEMT) device and monolithic microwave integrated circuit (MMIC) performance at microwave and millimeter wave frequencies. These selective etch PHEMT profiles exhibit a typical breakdown voltage as high as 25V with a peak transconductance,

Yi-Ching Pao; Kim Tran; Jeff Franklin; Mike Bailey

1999-01-01

356

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

357

Energy prediction of Amonix solar power plants  

NASA Astrophysics Data System (ADS)

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

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

2010-08-01

358

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

NASA Astrophysics Data System (ADS)

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

Yildiz, Faruk

359

Evaluation of turbulent magnetic energy spectra in the three-dimensional wave vector domain in the solar wind  

SciTech Connect

Using four-point measurements of the CLUSTER spacecraft, the energy distribution of magnetic field fluctuations in the solar wind is determined directly in the three-dimensional wave vector domain in the range 3 x 10{sup -4} rad/km < k < 3 x 10{sup -3} rad/km. The analysis method takes account of a regular tetrahedron configuration of CLUSTER and the Doppler effect. The energy distribution in the flow rest frame is anisotropic, characterized by two distinct extended structures perpendicular to the mean magnetic field and furthermore perpendicular to the flow direction. The three-dimensional distribution is averaged around the direction of the mean magnetic field direction, and then is further reduced to one-dimensional distributions in the wave number domain parallel and perpendicular to the mean magnetic field. The one-dimensional energy spectra are characterized by the power law with the index -5/3 and furthermore very close energy density between parallel and perpendicular directions to the mean magnetic field at the same wave numbers. Though the distributions and the spectra are not covered in a wide range of wave vectors, our measurements suggest that the solar wind fluctuation is anisotropic in the three-dimensional wave vector space. It is, however, rather isotropic when reduced into the parallel and perpendicular wave vector geometries due to the second anisotropy imposed by the flow direction.

Gary, S Peter [Los Alamos National Laboratory; Narita, Y [UNIV OF BRAUNSCHWEIG; Glassmeier, K H [UNIV OF BRAUNSCHWEIG; Goldstein, M L [NGSFC; Safraoui, F [NGSFC; Treumann, R A [UNIV. MUNICH

2009-01-01

360

Millileter-Wave Power-Combining Amplifier Using A Broadband Waveguide Combiner  

NASA Astrophysics Data System (ADS)

A Millimeter-wave power-combining amplifier based on the multi-way rectangular-waveguide power-dividing/combining circuit has been presented and investigated. The equivalent-circuit approach has been used to analyze the passive power-dividing/combining circuits. An eight-device amplifier is designed and measured to validate the power-dividing/combining mechanism using this technique. Both the measured 10-dB return loss bandwidth and the 2-dB insertion loss bandwidth of the passive system are more than 10 GHz. The measured maximum small-signal gain of the millimeter-wave eight-device power amplifier is 22.5 dB at 26.8 GHz with a 3-dB bandwidth of more than 6 GHz, while the input and output return loss of the proposed eight-device power amplifier is around -10 dB from 26 GHz to 36 GHz. The measured maximum output power at 1-dB compression from the power amplifier is 28 dBm at 29.5 GHz.

Song, Kaijun; Hu, Shunyong; Mo, Yuxia; Fan, Yong

2012-12-01

361

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

362

Impact localization and energy quantification based on the power flow: A low-power requirement approach  

NASA Astrophysics Data System (ADS)

The increasing use of composite materials has led to a dramatic change in the definition of safety standards. In particular, composite structures may be subjected to internal damages caused by external impacts that may not be detected by classical inspection methods. Additional constraints related to energy requirements may also be considered in order to make the system autonomous and possibly self-powered. The purpose of this paper is to present a low-cost impact detection and quantification scheme for thin plates or shells giving the whole history of the structure solicitation. Based on the analysis of the energy that has flown over a monitored area through the use of the elastic Poynting vector (that relates the mechanical power density of travelling waves), it is shown that this global energy balance may be linked in a simple way to the voltage output of piezoelectric elements in open-circuit condition. From this estimation, it is therefore possible to detect if an impact occurred inside the monitored area (in this case, the global energy balance would be positive) as well as its associated energy. If the impact occurs out of the frame, the global energy (and thus the obtained estimator) would be negative because of energy dissipation caused by internal losses and almost null. Thanks to this energy flow approach, the system is also independent from the boundary conditions of the structure. Experimental measurements aiming at validating the theoretical predictions showed that the technique permits detecting the impact area (inside/outside the frame) as well as an accurate estimation of the impact energy if the latter occurred inside the frame, both on a steel plate (with different boundary conditions) and an anisotropic composite structure.

Guyomar, Daniel; Lallart, Mickaël; Petit, Lionel; Wang, Xing-Jun

2011-06-01

363

Initiation of reactive blast waves by external energy sources  

NASA Astrophysics Data System (ADS)

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

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

2012-11-01

364

The use of remote sensing and linear wave theory to model local wave energy around Alphonse Atoll, Seychelles  

NASA Astrophysics Data System (ADS)

This paper demonstrates a practical step-wise method for modelling wave energy at the landscape scale using GIS and remote sensing techniques at Alphonse Atoll, Seychelles. Inputs are a map of the benthic surface (seabed) cover, a detailed bathymetric model derived from remotely sensed Compact Airborne Spectrographic Imager (CASI) data and information on regional wave heights. Incident energy at the reef crest around the atoll perimeter is calculated as a function of its deepwater value with wave parameters (significant wave height and period) hindcast in the offshore zone using the WaveWatch III application developed by the National Oceanographic and Atmospheric Administration. Energy modifications are calculated at constant intervals as waves transform over the forereef platform along a series of reef profile transects running into the atoll centre. Factors for shoaling, refraction and frictional attenuation are calculated at each interval for given changes in bathymetry and benthic coverage type and a nominal reduction in absolute energy is incorporated at the reef crest to account for wave breaking. Overall energy estimates are derived for a period of 5 years and related to spatial patterning of reef flat surface cover (sand and seagrass patches).

Hamylton, S.

2011-12-01

365

Powerful GeV emission from a ?-ray-burst shock wave scattering stellar photons  

NASA Astrophysics Data System (ADS)

The ?-ray bursts (GRBs) of long duration are very likely to be connected to the death of massive stars. The ?-ray emission is believed to come from energy released internally in a flow that moves at ultrarelativistic speed. The fast flow drives a shock wave into the external medium leading to the afterglow emission. Most massive stars form in dense clusters, their high luminosity producing a very dense radiation field. Here, I explore the observational consequences of the interaction of the shocked external medium of the burst with the photon field of a nearby O star. I show that inverse Compton scattering of the stellar photons by electrons heated by the shock leads to powerful ?-ray emission in the ~1-100 GeV range. This emission appears minutes to hours after the burst and can be easily detected by Cherenkov telescopes and probably with the GLAST satellite. This signal may have already been observed in GRB 940217 and can yield important information about the circumburst environment.

Giannios, Dimitrios

2009-05-01

366

Powerful GeV emission from a ?-ray-burst shock wave scattering stellar photons  

NASA Astrophysics Data System (ADS)

The ?-ray bursts (GRBs) of long duration are very likely to be connected to the death of massive stars. The ?-ray emission is believed to come from energy released internally in a flow that moves at ultrarelativistic speed. The fast flow drives a shock wave into the external medium leading to the afterglow emission. Most massive stars form in dense clusters, their high luminosity producing a very dense radiation field. Here, I explore the observational consequences of the interaction of the shocked external medium of the burst with the photon field of a nearby O star. I show that inverse Compton scattering of the stellar photons by electrons heated by the shock leads to powerful ?-ray emission in the ~1-100 GeV range. This emission appears minutes to hours after the burst and can be easily detected by Cherenkov telescopes and probably with the GLAST satellite. This signal may have already been observed in GRB 940217 and can yield important information about the circumburst environment and the extragalactic background light.

Giannios, D.

2008-09-01

367

Effect of powerful oblique HF waves on ionospheric D-layer absorption  

NASA Astrophysics Data System (ADS)

A simple model of D-layer ionospheric heating in the presence of strong, high frequency (HF) radio waves is used to predict the anomalous, nonlinear wave absorption due to collisional and recombination effects induced by the indirect signal. It is found that little anomalous absorption occurs until effective radiated power (ERP) approaches 100 dBW; further increases in power of several dB beyond this 100 dBW threshold are frustrated by a comparable increase in self-induced, one-way absorption. This trend of increasing absorption with increasing transmitter ERP has considerable implications for design of communication or radar systems that use ultra-powerful, high-gain HF transmitters.

Bloom, R. M.

1993-04-01

368

Midlatitude propagation of VLF to MF waves through nighttime ionosphere above powerful VLF transmitters  

NASA Astrophysics Data System (ADS)

nighttime observations made by the DEMETER satellite in the very low frequency (VLF) to medium frequency (MF) bands (3 kHz to 3 MHz) have demonstrated the propagation of radio waves from the bottom of ionosphere up to the satellite altitude (~700 km). Propagation characteristics derived from the magneto-ionic theory [Budden, ] are used to explain the absence of wave observations between ~1 and 2 MHz. Under hypotheses made for the Appleton and Hartree (or Appleton and Lassen) formula, studies of the vertical variations of the real and imaginary parts of the refractive index are performed to point out modifications in the propagation characteristics of the waves: (i) at the crossing of the plasma cutoffs regions, (ii) at the crossing of the ordinary and extraordinary mode resonance regions, and (iii) in the region where the product of the collision frequency (?) and the electronic density (Ne) is maximum. It is shown that enhancements in the collision frequencies, produced by powerful VLF transmitters in the region where the product of ? and Ne is maximum, open the half angle of the MF wave transmission cones and increase the power densities of those waves at the DEMETER altitude.

Lefeuvre, F.; PinçOn, J. L.; Parrot, M.

2013-03-01

369

Solar power satellite life-cycle energy recovery consideration  

Microsoft Academic Search

The construction, in-orbit installation and maintenance of a solar power satellite (SPS) will demand large amounts of energy. As a minimum requirement for an energy effective power satellite it is asked that this amount of energy be recovered. The energy effectiveness in this sense resulting in a positive net energy balance is a prerequisite for cost-effective power satellite. This paper

S. Weingartner; J. Blumenberg

1994-01-01

370

Numerical modeling on hydrodynamic performance of a bottom-hinged flap wave energy converter  

NASA Astrophysics Data System (ADS)

The hydrodynamic performance of a bottom-hinged flap wave energy converter (WEC) is investigated through a frequency domain numerical model. The numerical model is verified through a two-dimensional analytic solution, as well as the qualitative analysis on the dynamic response of avibrating system. The concept of "optimum density" of the bottom-hinged flap is proposed, and its analytic expression is derived as well. The frequency interval in which the optimum density exists is also obtained. The analytic expression of the optimum linear damping coefficient is obtained by a bottom-hinged WEC. Some basic dynamic properties involving natural period, excitation moment, pitch amplitude, and optimum damping coefficient are analyzed and discussed in detail. In addition, this paper highlights the analysis of effects on the conversion performance of the device exerted by some important parameters. The results indicate that "the optimum linear damping period of 5.0 s" is the most ideal option in the short wave sea states with the wave period below 6.0 s. Shallow water depth, large flap thickness and low flap density are advised in the practical design of the device in short wave sea states in order to maximize power capture. In the sea state with water depth of 5.0 m and wave period of 5.0 s, the results of parametric optimization suggest a flap with the width of 8.0 m, thickness of 1.6 m, and with the density as little as possible when the optimum power take-off (PTO) damping coefficient is adopted.

Zhao, Hai-tao; Sun, Zhi-lin; Hao, Chun-ling; Shen, Jia-fa

2013-03-01

371

Optical Models from Low-Energy S-, p- and D-Wave Cross Sections.  

National Technical Information Service (NTIS)

From transmission measurements with good resolution at low energies one can obtain data on the optical model potential (OMP) for individual partical waves by first making a multilevel analysis to isolate the partial waves and then averaging for comparison...

C. H. Johnson

1984-01-01

372

Adaptive power management in energy harvesting systems  

Microsoft Academic Search

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

Clemens Moser; Lothar Thiele; Davide Brunelli; Luca Benini

2007-01-01

373

Energy and Power Technology. Curriculum Guide.  

ERIC Educational Resources Information Center

One of a set of six guides for an industrial arts curriculum at the junior high school level, this guide provides the basic foundation to develop a one-semester course based on the cluster concept, energy and power technology. The guide suggests manipulative and experimental student-conducted activities or teacher demonstrations which focus on the…

North Dakota State Board for Vocational Education, Bismarck.

374

Tower Power: Producing Fuels from Solar Energy  

ERIC Educational Resources Information Center

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

Antal, M. J., Jr.

1976-01-01

375

Active power filter with hybrid energy storage  

Microsoft Academic Search

An active power filter that uses an impressed current converter and an inductive-capacitive energy storage circuit is presented. This storage includes a switching section to interface the inductive and capacitive element. This solution allows independent choice of the converter configuration and of the type of storage system which, in this particular case, is mainly capacitive. The theory of operation is

L. Malesani; L. Rossetto; P. Tenti

1991-01-01

376

Laboratory investigations of Alfven waves in a high power helicon plasma with density gradients  

NASA Astrophysics Data System (ADS)

Alfven wave dissipation is the primary physical process that underlies a leading theoretical model of coronal ion heating in the Sun. Data from Hinode, the recently launched high-resolution solar imaging mission [Erdelyi and Fedun, Science, Dec. 2007], has provided strong evidence for the presence of Alfven waves in the corona and in coronal loops. These Hinode observations have the potential to explain the million-degree difference between ion temperatures in the corona and at the top of the photosphere. Laboratory investigations of Alfven wave propagation and damping typically require long plasma sources, needed to accommodate the long wavelength waves. Shorter experimental systems can be employed if the plasma density in the source is orders of magnitude larger. Such high densities can be achieved in helicon sources. Their high plasma density (˜1013 cm -3) yields Alfven wavelengths on the order of a few meters. However, helicon sources usually have a steep radial density gradient. The steep gradient introduces two regimes of Alfven wave propagation: kinetic (beta > me/mi) and inertial (beta < me/mi), where beta is the ratio of total pressure to total magnetic field pressure. At the boundary between the two regimes, magnetic energy can accumulate due to a decrease in perpendicular group velocity of the waves. This dissertation reports the first experimental observation of propagating kinetic Alfven waves in a helicon source. The kinetic model fit to the dispersion measurements includes the effects of ion-neutral damping, the magnitude of which is determined through in-situ neutral density measurements. The measurements are also consistent with the pileup of wave energy at the kinetic and inertial Alfven boundary.

Houshmandyar, Saeid

377

Wind power: The new energy policy 1  

NASA Astrophysics Data System (ADS)

Increasing use of renewable energy sources is an important aspect of the new energy policy of the State government of Schleswig-Holstein. Technical and industrial innovation are involved. By expanding and developing these regionally available inexhaustible energy sources to generate electricity and heat, we are contributing to environmental protection and helping to reduce adverse affects on the climate. We are also taking our limited resources into account and expanding energy generation in a logical manner. Wind energy is the most attractive renewable energy source for Schleswig-Holstein because our State is well known for its strong winds and constant fresh breeze. For this reason the State government has made expansion of wind energy one of its primary areas of emphasis. The goals of our promotion measures includes ongoing technical and engineering development of wind energy facilities, increasing the level of use of the wind, and increasing the percentage of wind energy used for power generation. This brochure is intended to demonstrate the significance and possibilities of wind energy for our State, to outline the legal requirements for erecting wind energy facilities, and to explain the many promotion measures. It represents a favorable breeze for wind.

1991-10-01

378

Some problems in modelling water waves for the study of back-scattering of microwave radio energy  

Microsoft Academic Search

Existing information on back-scattering of centimeter radio energy by ocean waves is examined with the thought that back-scattering might be modelled using small water waves and millimeter radio waves. The author concludes that such modeling will be unsuccessful because the scattering of millimeter radio waves will be by capillary water waves rather than gravity waves.

Raymond C. Staley

1958-01-01

379

Impact of nonlinear energy transfer on the wave field in Pacific hindcast experiments  

NASA Astrophysics Data System (ADS)

We investigated the impact of nonlinear energy transfer (Snl) on wave fields by performing hindcast experiments for the Pacific Ocean. Specifically, we evaluated model performance using SRIAM, which was developed to accurately reproduce Snl with lower computational cost than more rigorous algorithms. The model results were compared to in situ wave parameters as well as results from another model employing the widely used discrete interaction approximation method (DIA). Comparison of the model results with buoy observations revealed a negligible difference between SRIAM and DIA for significant wave heights. However, the difference for the peak period was quite pronounced, especially around the tropical Pacific, where a persistent bias in peak frequency was improved by using SRIAM. This study also highlights the impact of source terms on spectral shape under a realistic model setting. Detailed analysis of spectral shape indicated that SRIAM can quantitatively capture the overshoot phenomena around the spectral peak during wave growth. In addition, Snl played a major role in maintaining the equilibrium range; it reacted to changes in the net external sources to cancel out the total source term. These results show that the magnitude of high-frequency dissipation controls the spectral tail exponent and that the balanced net external source is responsible for the reproduction of the f-4 power law behavior in the equilibrium range.

Tamura, Hitoshi; Waseda, Takuji; Miyazawa, Yasumasa

2010-12-01

380

Shock-wave energy and acoustic energy dissipation after laser-induced breakdown  

NASA Astrophysics Data System (ADS)

We investigated the spatial distribution of energy dissipation during propagation of the shock front arising from optical breakdown in water, because it is related to the stress- induced cellular changes in plasma-mediated laser surgery. The dissipation can be calculated from the shock wave velocity (mu) s by a relation derived from the Rankine-Hugoniot equation. (mu) s was measured as a function of time and space for various laser parameters. With a 1 mJ/6-ns pulse, 64% of the absorbed light energy are converted into acoustic energy, but the largest part of this energy are converted into heat already within the first 200 micrometer of shock front propagation. Afterwards, the dissipation occurs at a much slower rate. Only approximately 10% of the acoustic energy reaches a distance of 10 mm. Far-field measurements can thus be very misleading for an energy balance. The energy dissipation at the shock front leads to a temperature rise of the medium. At 10 mJ pulse energy, the temperature close to the plasma exceeds the critical point of water. This means that the shock wave passage goes along with an enlargement of the cavitation bubble. High-pressure-induced bubble formation can also occur at locations further away from the laser plasma where shock waves from adjacent plasmas interfere. We have thus demonstrated a mechanism of stress wave induced cavitation which does not rely on tensiel stress, but on very high overpressures. Since most of the dissipation takes place within the first 200 micrometer, the shock wave effects are mostly covered by the effects of the cavitation bubble which reaches a radius of 800 micrometer in water at the same laser parameters. Acoustic tissue effects are, nevertheless important, because the bubble is smaller in tissue than in water, the weakening of the tissue structure by the shock wave passage probably contributes to the cavitation-induced damage, and the range for acoustic damage is larger in nonspherical geometries.

Vogel, Alfred; Noack, Joachim

1998-05-01

381

Integration of distributed energy sources with electrical power grid  

Microsoft Academic Search

The changes that have been taking place recently in the power sector, lead to an increasing share of distributed generation (DG) in the electric power production. Many different energy sources can be distinguished in this area and majority of them incorporate power electronic electrical energy converters interfacing with a power system. Connection of a large number of distributed energy sources

I. WASIAK; Z. HANZELKA

382

PARTICLE ENERGY SPECTRA AT TRAVELING INTERPLANETARY SHOCK WAVES  

SciTech Connect

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

Reames, Donald V., E-mail: dvreames@umd.edu [Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742 (United States)

2012-09-20

383

A twin unidirectional impulse turbine for wave energy conversion  

NASA Astrophysics Data System (ADS)

A twin unidirectional impulse turbine has been proposed in order to enhance the performance of wave energy plant. This turbine system uses two unidirectional impulse turbines and their flow direction is different from each other. However, the turbine characteristics have not been clarified to date. The performances of a unidirectional impulse turbine under steady flow conditions were investigated experimentally by using a wind tunnel with large piston/cylinder in this study. Then, efficiency of the twin impulse turbine have been estimated by a quasi-steady analysis using experimental results.

Takao, Manabu; Takami, Akiyasu; Okuhara, Shinya; Setoguchi, Toshiaki

2011-10-01

384

A Nonlinear Energy Balance Model of Particle Acceleration by Collisionless Parallel Shock Waves  

NASA Astrophysics Data System (ADS)

We describe in this Letter a new way to model processes of particle acceleration in quasi-parallel shocks and report some promising preliminary results of numerical analysis. The treatment of plasma and waves is self-consistent and time-dependent but nevertheless relatively simple from a physical point of view. The model assumes that resonant wave-particle interaction is the most important mechanism for both shock formation and particle acceleration but does not use the diffusion-convection approach for the interaction. Instead it uses conservation laws and resonance conditions to find where waves will be generated or dumped and hence particles pitch-angle scattered. Because the distribution function for bulk plasma and not just the high-energy tail is included in the model, no special bootstrap or termination assumptions are required (neither the introduction of a separate population of seed particles nor some ad hoc escape rate of accelerated particles is needed). In spite of all the simplicity, the preliminary results not only show remarkable agreement with diffusive shock acceleration models in the prediction of power spectra for accelerated particles in the upstream region but also reveal the presence of a spectral break in the high-energy part of the spectra. The results also confirm that acceleration can start from the thermal particles and confirm the importance of second-order Fermi acceleration.

Galinsky, V. L.; Shevchenko, V. I.

2007-11-01

385

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

Microsoft Academic Search

Interaction between the midlatitude jet and gravity waves is examined, focusing on the nonnormality of the underlying linear dynamics, which plays an essential role in processing the wave activity and selecting structures that dominate wave momentum and energy transport. When the interior of a typical midlatitude jet is stochastically forced, waves with short horizontal wavelength are trapped inside the jet

Nikolaos A. Bakas; Brian F. Farrell

2008-01-01

386

Rayleigh type bending waves in anisotropic media  

Microsoft Academic Search

The existence, dispersion properties, velocities and energy of waves, localized near the stress-free edge of thin anisotropic plates are investigated. As shown, some qualitatively new effects occur: the velocity of Rayleigh type waves can be not minimal between bending waves; wave decay takes place with oscillations; under some type of anisotropy, power flow can equal zero and can change the

D. D. Zakharov; W. Becker

2003-01-01

387

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

Microsoft Academic Search

Conventional electrochemical batteries power most of the portable and wireless electronic devices that are operated by electric power. In the past few years, electrochemical batteries and energy storage devices have improved significantly. However, this progress has not been able to keep up with the development of microprocessors, memory storage, and sensors of electronic applications. Battery weight, lifespan and reliability often

Faruk Yildiz

2008-01-01

388

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

SciTech Connect

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

Bigelow, T.S.

1997-08-01

389

Digitally Controlled Low Frequency Square Wave Electronic Ballast with Resonant Ignition and Power Loop  

Microsoft Academic Search

The paper proposes a digital controller for a low frequency square wave (LFSW) electronic ballast implemented in a dsPIC30F2010 microcontroller that includes: the ignition sequence, a double control loop and the selection of the positive and negative operation modes. The whole ballast is a two stage circuit, where the first stage is a power factor correction (PFC) stage and the

F. Javier Díaz; Francisco J. Azcondo; Christian Brañas; Rosario Casanueva; Regan Zane

2007-01-01

390

Control of square-wave inverters in high-power hybrid active filter systems  

Microsoft Academic Search

This paper presents a new control scheme for a hybrid parallel active filter (HPAF) system intended for high-power applications-up to 100 MW nonlinear loads-to meet IEEE 519 recommended harmonic standards. The active filter inverter is realized with small-rated (1%-2% of the load rating) square-wave inverters operating at the dominant harmonic frequencies. The proposed system achieves harmonic isolation at desired dominant

Po-Tai Cheng; Subhashish Bhattacharya; Deepak M. Divan

1998-01-01

391

Observations of ionospheric cavities generated by high-power radio waves  

Microsoft Academic Search

High-power hf electromagnetic waves have been used to generate large electron-density cavities in the night-time F-region ionospheric plasma. Previous modification experiments have described induced density perturbations of only a few percent. Here we report the first observations of density depletions exceeding 50%, extending hundreds of kilometers along the geomagnetic field. These cavities are thermally driven, with electron temperatures in the

L.M. Duncan; J. P. Sheerin; R.A. Behnke

1988-01-01

392

Experimental investigation of a Ka band high power millimeter wave generator operated at low guiding magnetic field  

SciTech Connect

An overmoded slow wave type Ka band generator is investigated experimentally to produce high power millimeter waves in this paper. The experiments were carried out at the TORCH-01 accelerator. The produced microwave frequency was measured by dispersive line method, and the power was estimated by integrating over the radiation pattern at far field. With relatively low guiding magnetic field of 0.8 T and diode voltage and beam current of 590 kV and 5.2 kA, respectively, a 33.56 GHz millimeter wave with an output power of 320 MW was generated, and the microwave mode was quasi-TM{sub 01} mode.

Zhu Jun; Shu Ting; Zhang Jun; Li Guolin; Zhang Zehai; Fan Yuwei [College of Optoelectric Science and Engineering, National University of Defense Technology, Changsha 410073 (China)

2011-05-15

393

Public attitudes and behavior regarding energy conservation: detailed tabulations by U. S. population segments; Waves 28 and 29. Monthly tabulated report  

Microsoft Academic Search

This report contains tabulations of results of telephone interviews conducted by Opinion Research Corporation on the following topics: attitudes toward nuclear power plants; the impact of school programs on home energy consumption; factors affecting the public's use of mass transit; company efforts at energy conservation. The interviewing period for Wave 28 began on April 7 and continued through April 21,

M. Rappeport; P. Labaw

1974-01-01

394

Experimental investigation of change of energy of infragavity waves in dependence on spectral characteristics of an irregular wind waves in coastal zone  

NASA Astrophysics Data System (ADS)

An infragravity waves are long waves with periods of 20 - 300 s. Most essential influence of infragarvity waves on dynamic processes is in a coastal zone, where its energy can exceed the energy of wind waves. From practical point of view, the infragravity waves are important, firstly, due to their influence on sand transport processes in a coastal zone. For example, interacting with group structure of wind waves the infragravity waves can define position of underwater bars on sandy coast. Secondly, they are responsible on formation of long waves in harbors. Main source of infragravity waves is wave group structure defined by sub-nonlinear interactions of wind waves (Longuet-Higgins, Stewart, 1962). These infragravity waves are bound with groups of wind waves and propagate with wave group velocity. Another type of infragravity waves are formed in a surf zone as a result of migration a wave breaking point (Symonds, et al., 1982). What from described above mechanisms of formation of infragravity waves prevails, till now it is unknown. It is also unknown how energy of infragravity waves depends on energy of input wind waves and how it changes during nonlinear wave transformation in coastal zone. In our work on the basis of the analysis of data of field experiment and numerical simulation a contribution of infragravity waves in total wave energy in depending on integral characteristics of an irregular wave field in the conditions of a real bathymetry was investigated. For analysis the data of field experiment "Shkorpilovtsy-2007" (Black sea) and data of numerical modeling of Boussinesq type equation with extended dispersion characteristics (Madsen et al., 1997) were used. It was revealed that infragravity waves in a coastal zone are defined mainly by local group structure of waves, which permanently changes due to nonlinearity, shoaling and breaking processes. Free infragravity waves appearing after wave breaking exist together with bound infragravity waves. There are no clear total dependences of energy of infrragravity waves from energy of wind waves and mean period of infragravity waves from mean period of wind waves. But significant wave height of infragravity waves depends on relative water depth (wave height of wind waves divided on water depth). There are different types of this dependence for breaking and non-breaking waves. The influence of peak period, significant wave height and directional spreading of initial wave spectrum on these dependences are discussed. The peculiarities of spectra of infragravity waves for non-breaking, breaking and multibreaking wind waves are shown. This work is supported by the RFBR, project 12-05-00965. References: Longuet-Higgins, M. S., R. W. Stewart, 1962. Radiation stress and mass transport in gravity waves, with an application to surf beats. J. Fluid Mech., 13, pp. 481-504. Symonds G., D.A. Huntley, A.J. Bowen, 1982. Two dimensional surf beat: long wave generation by a time-varying breakpoint. J. of Geoph. Res., 87(C), pp.492-498. Madsen P.A., Sorensen O.R., Shaffer H.A. 1997. Surf zone dynamics simulated by a Boussinesq type model. Coastal Engineering, 32, p. 255-287.

Saprykina, Yana; Divinskii, Boris

2013-04-01

395

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

SciTech Connect

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

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

2012-07-15

396

The dissipation of wind wave energy across a fringing reef at Ipan, Guam  

NASA Astrophysics Data System (ADS)

Field observations over a fringing reef at Ipan, Guam, during trade wind and tropical storm conditions are used to assess the transformation of sea and swell energy from the fore reef to the shoreline. Parameterizations of wave breaking and bottom friction developed for sandy beaches are found to represent the observed decay in wave energy with an increased friction coefficient. These parameterizations are incorporated into the one-dimensional energy flux balance, which is integrated across the reef to assess the effects of varying tidal range, incident wave height and reef bathymetry on the sea and swell band wave height and wave setup near the shoreline. Wave energy on the reef is strongly depth-limited and controlled by the reef submergence level. Shoreline wave energy increases with incident wave height largely due to the increase in water level from breaking wave setup. Increased tidal levels result in increased shoreline energy, since wave setup is only weakly reduced. The wave height at the shore is shown to be inversely proportional to the width of the reef flat due to dissipation.

Péquignet, A.-C.; Becker, J. M.; Merrifield, M. A.; Boc, S. J.

2011-06-01

397

Cytotoxicity of high energy shock waves: methodologic considerations.  

PubMed

In vivo and in vitro experimentation with high energy shock waves (HESW) is necessary to further our understanding of the biologic effects and potential application of this novel energy form. Factors are identified which are critical to the design and subsequent interpretation of HESW experimentation. First, the nature of the containment vessel and the presence or absence of acoustic interfaces are shown to significantly alter the outcome of cell suspension experiments. Second, the effects of HESW are shown to differ markedly for cells in suspension versus cells in tissue making comparisons between the two uncertain. Finally, the need for appropriate negative controls is demonstrated with in vivo experiments to control for the generalized toxicity which occurs when small animals are exposed to such an intense force distributed over a relatively large area. These findings affect the interpretation of previously reported work which investigated the cytotoxic potential of HESW. PMID:2926909

Laudone, V P; Morgan, T R; Huryk, R F; Heston, W D; Fair, W R

1989-04-01

398

An ocean kinetic energy converter for low-power applications using piezoelectric disk elements  

NASA Astrophysics Data System (ADS)

The main problem facing long-term electronic system deployments in the sea, is to find a feasible way to supply them with the power they require. Harvesting mechanical energy from the ocean wave oscillations and converting it into electrical energy, provides an alternative method for creating self-contained power sources. However, the very low and varying frequency of ocean waves, which generally varies from 0.1 Hz to 2 Hz, presents a hurdle which has to be overcome if this mechanical energy is to be harvested. In this paper, a new sea wave kinetic energy converter is described using low-cost disk piezoelectric elements, which has no dependence on their excitement frequency, to feed low-consumption maritime-deployed electronic devices. The operating principles of the piezoelectric device technique are presented, including analytical formulations describing the transfer of energy. Finally, a prototypical design, which generates electrical energy from the motion of a buoy, is introduced. The paper concludes with the the behavior study of the piezoelectric prototype device as a power generator.

Viñolo, C.; Toma, D.; Mànuel, A.; del Rio, J.

2013-09-01

399

Linear PM Generator system for wave energy conversion in the AWS  

Microsoft Academic Search

The Archimedes Wave Swing is a system that converts ocean wave energy into electric energy. A pilot plant of this system has been built. The generator system consists of a permanent-magnet linear synchronous generator with a current source inverter (CSI). The correlation between the measured and the calculated parameters of the designed generator is reasonable. The annual energy yield of

Henk Polinder; Michiel E. C. Damen; Fred Gardner

2004-01-01

400

Traveling wave device for combining or splitting symmetric and asymmetric waves  

DOEpatents

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

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

2005-07-19

401

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

NASA Astrophysics Data System (ADS)

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

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

2005-10-01

402

Liquid wall inertial fusion energy power plants  

Microsoft Academic Search

Liquid walls interposed between the microexplosions and the chamber structural wall give an inertial fusion energy (IFE) power plant designer flexibility and result in profound advantages. For example, the fusion chamber walls behind the liquid can be made using existing materials (e.g. steel) and last as long as the plant itself without replacement while still meeting non-nuclear-grade construction standards and

Ralph W. Moir

1996-01-01

403

Power Management for Energy Harvesting Wireless Sensors  

Microsoft Academic Search

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

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

2005-01-01

404

Power management for energy harvesting wireless sensors  

Microsoft Academic Search

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

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

2005-01-01

405

Energy management in fuel cell power trains  

Microsoft Academic Search

In this paper, experimental results obtained on a small size fuel cell power train (1.8kW) based on a 500W proton exchange membrane (PEM) stack are reported and discussed with specific regard to energy management issues to be faced for attainment of the maximum propulsion system efficiency. The fuel cell system (FCS) was realized and characterized via investigating the effects of

P. Corbo; F. E. Corcione; F. Migliardini; O. Veneri

2006-01-01

406

A new scheme of nonlinear energy transfer among wind waves: RIAM method-algorithm and performance-  

Microsoft Academic Search

A numerical scheme for calculating the nonlinear energy transfer among wind waves (RIAM method) was developed on the basis of the rigorous method of Masuda. Then the performance of the RIAM method was examined by applying it to various forms of wind-wave spectra and different situations of wind-wave evolution, in comparison mainly with the WAM method. The computational time of

Kosei Komatsu; Akira Masuda

1996-01-01

407

Energy storage and dispersion of surface acoustic waves trapped in a periodic array of mechanical resonators  

Microsoft Academic Search

It has been shown previously that surface acoustic waves can be efficiently trapped and slowed by steep ridges on a piezoelectric substrate, giving rise to two families of shear-horizontal and vertically polarized surface waves. The mechanisms of energy storage and dispersion are explored by using the finite element method to model surface acoustic waves generated by high aspect ratio electrodes.

Maria B. Dühring; Vincent Laude; Abdelkrim Khelif

2009-01-01

408

Energy Drinks and Food Bars: Power or Hype?  

MedlinePLUS

Energy Drinks and Food Bars: Power or Hype? KidsHealth > Teens > Food & Fitness > Nutrition Basics > Energy Drinks and ... Downsides Cutting Through the Hype The Buzz on Energy Foods Energy drinks and nutrition bars often make ...

409

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

SciTech Connect

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

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

1995-10-01

410

Performance of Textured Carbon on Copper Electrode Multistage Depressed Collectors with Medium-Power Traveling Wave Tubes.  

National Technical Information Service (NTIS)

Performance of multistage depressed collectors (MDCs) using textured carbon on copper substrate electrode surfaces was evaluated in conjunction with medium-power traveling wave tubes (TWTs). The MDC and TWT overall efficiencies for these electrodes were m...

P. Ramins A. N. Curren

1986-01-01

411

The Varr Method: A Technique for Determining the Effective Power Patterns of Millimeter-Wave Radiometric Antennas.  

National Technical Information Service (NTIS)

The VARR (VAriable Range Reflector) Method is a technique which has been developed to measure the effective power patterns of millimeter-wave radiometric antennas. In this method, a large movable metallic surface is oriented to reflect radiation from the ...

R. B. Patton C. L. Wilson

1966-01-01

412

Induced EM Field and Absorbed Power Density Inside Human Torsos by 1 to 500 MHZ EM Waves.  

National Technical Information Service (NTIS)

Presented are numerical results on the internal EM field and absorbed power density inside a human torso induced by EM waves of frequencies ranging from 1 to 500 MHz and of both vertical and horizontal polarizations.

B. S. Guru K. M. Chen

1976-01-01

413

Energy transformations and dissipation of nonlinear internal waves over New Jersey's continental shelf  

NASA Astrophysics Data System (ADS)

The energetics of large amplitude, high-frequency nonlinear internal waves (NLIWs) observed over the New Jersey continental shelf are summarized from ship and mooring data acquired in August 2006. NLIW energy was typically on the order of 105 Jm-1, and the wave dissipative loss was near 50 W m-1. However, wave energies (dissipations) were ~10 (~2) times greater than these values during a particular week-long period. In general, the leading waves in a packet grew in energy across the outer shelf, reached peak values near 40 km inshore of the shelf break, and then lost energy to turbulent mixing. Wave growth was attributed to the bore-like nature of the internal tide, as wave groups that exhibited larger long-term (lasting for a few hours) displacements of the pycnocline offshore typically had greater energy inshore. For ship-observed NLIWs, the average dissipative loss over the region of decay scaled with the peak energy in waves; extending this scaling to mooring data produces estimates of NLIW dissipative loss consistent with those made using the flux divergence of wave energy. The decay time scale of the NLIWs was approximately 12 h corresponding to a length scale of 35 km (O(100) wavelengths). Imposed on these larger scale energetic trends, were short, rapid exchanges associated with wave interactions and shoaling on a localized topographic rise. Both of these events resulted in the onset of shear instabilities and large energy loss to turbulent mixing.

Shroyer, E. L.; Moum, J. N.; Nash, J. D.

2010-08-01

414

Power system dynamics influenced by a power electronic interface for variable speed wind energy conversion systems  

Microsoft Academic Search

A study of the influence of a wind energy conversion system on power system dynamics is presented in this paper. The wind energy conversion system is interfaced into a power system through a power electronic system including a voltage source converter (VSC) at the grid side. This paper investigates the system performance during a power system disturbance; a voltage sag

Z. Chen; Y. Hu

2004-01-01

415

Plasma physics and related challenges of millimeter-wave-to-terahertz and high power microwave generation  

NASA Astrophysics Data System (ADS)

Homeland security and military defense technology considerations have stimulated intense interest in mobile, high power sources of millimeter-wave (mmw) to terahertz (THz) regime electromagnetic radiation, from 0.1 to 10 THz. While vacuum electronic sources are a natural choice for high power, the challenges have yet to be completely met for applications including noninvasive sensing of concealed weapons and dangerous agents, high-data-rate communications, high resolution radar, next generation acceleration drivers, and analysis of fluids and condensed matter. The compact size requirements for many of these high frequency sources require miniscule, microfabricated slow wave circuits. This necessitates electron beams with tiny transverse dimensions and potentially very high current densities for adequate gain. Thus, an emerging family of microfabricated, vacuum electronic devices share many of the same plasma physics challenges that are currently confronting ``classic'' high power microwave (HPM) generators including long-life bright electron beam sources, intense beam transport, parasitic mode excitation, energetic electron interaction with surfaces, and rf air breakdown at output windows. The contemporary plasma physics and other related issues of compact, high power mmw-to-THz sources are compared and contrasted to those of HPM generation, and future research challenges and opportunities are discussed.

Booske, John H.

2008-05-01

416

Plasma physics and related challenges of millimeter-wave-to-terahertz and high power microwave generation  

SciTech Connect

Homeland security and military defense technology considerations have stimulated intense interest in mobile, high power sources of millimeter-wave (mmw) to terahertz (THz) regime electromagnetic radiation, from 0.1 to 10 THz. While vacuum electronic sources are a natural choice for high power, the challenges have yet to be completely met for applications including noninvasive sensing of concealed weapons and dangerous agents, high-data-rate communications, high resolution radar, next generation acceleration drivers, and analysis of fluids and condensed matter. The compact size requirements for many of these high frequency sources require miniscule, microfabricated slow wave circuits. This necessitates electron beams with tiny transverse dimensions and potentially very high current densities for adequate gain. Thus, an emerging family of microfabricated, vacuum electronic devices share many of the same plasma physics challenges that are currently confronting 'classic' high power microwave (HPM) generators including long-life bright electron beam sources, intense beam transport, parasitic mode excitation, energetic electron interaction with surfaces, and rf air breakdown at output windows. The contemporary plasma physics and other related issues of compact, high power mmw-to-THz sources are compared and contrasted to those of HPM generation, and future research challenges and opportunities are discussed.

Booske, John H. [Electrical and Computer Engineering, University of Wisconsin-Madison, 1415 Engineering Drive, Madison, Wisconsin 53706 (United States)

2008-05-15

417

Power definition and energy measurement based on waveform similarity  

Microsoft Academic Search

For the characteristics of non-linear, imbalance and fluctuation, a large quantity of harmonic and negative sequence current will be injected to the power grid by the traction load of electric railway, which will lead to the serious distortion of the source voltage. Under this circumstance, the original definition of reactive power in the form of sine wave is unsuitable and

L. X. Zhou; Z. D. Yin; X. N. Xiao

2008-01-01

418

A novel cascode power matching approach for high efficiency tapered traveling wave power amplifiers in SiGe BiCMOS  

Microsoft Academic Search

In this paper we present a novel cascode power matching approach for high efficiency ultra-wideband traveling wave power amplifiers using 0.25 mum SiGe HBT transistors. An inductor between the two cascode transistors increases the output impedance, the bandwidth, and the maximum output power. Design trade-offs for maximum bandwidth, gain, output power, and efficiency are discussed by means of analytical calculations

Benjamin Sewiolo; Benjamin Waldmann; Georg Fischer; Robert Weigel

2009-01-01

419

A non-intrusive beam power monitor for high power pulsed or continuous wave lasers  

DOEpatents

A system for monitoring the output of a laser is provided in which the output of a photodiode disposed in the cavity of the laser is used to provide a correlated indication of the laser power. The photodiode is disposed out of the laser beam to view the extraneous light generated in the laser cavity whose intensity has been found to be a direct correlation of the laser beam output power level. Further, the system provides means for monitoring the phase of the laser output beam relative to a modulated control signal through the photodiode monitor. 4 figs.

Hawsey, R.A.; Scudiere, M.B.

1989-09-26

420

Wind energy-hydrogen storage hybrid power generation  

Microsoft Academic Search

SUMMARY In this theoretical investigation, a hybrid power generation system utilizing wind energy and hydrogen storage is presented. Firstly, the available wind energy is determined, which is followed by evaluating the e$ciency of the wind energy conversion system. A revised model of windmill is proposed from which wind power density and electric power output are determined. When the load demand

Wen-Jei Yang; Orhan Aydin

2001-01-01

421

Electrical Power Production Facilities from Green Energy Sources  

Microsoft Academic Search

Green power refers to electricity supplied from more readily renewable energy sources than traditional electrical power sources. Green power products have become widespread in many electricity markets worldwide and can be derived from renewable energy sources. The environmental advantages of the production and use of green electricity by using green electricity seem to be clear. Using green energy sources like

Ayhan Demirbas

2006-01-01

422

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

PubMed

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

Langhamer, Olivia; Wilhelmsson, Dan

2009-06-06

423

A hysteresis effect in the generation of field-aligned irregularities by a high-power radio wave  

Microsoft Academic Search

The anomalous self-absorption of a high-power radio wave measured during recent ionospheric modification experiments exhibits a hysteresis effect. These results are consistent with the assumption that the growth of field-aligned irregularities due to the interaction of a high-power pump wave and the ionospheric plasma occurs in two stages. During the first stage, striation growth is due to an instability which

T. B. Jones; T. Robinson; P. Stubbe; H. Kopka

1983-01-01

424

Comparison of low-power single-stage boost rectifiers for sub-milliwatt electromagnetic energy harvesters  

NASA Astrophysics Data System (ADS)

Energy harvesting could provide power-autonomy to many important embedded sensing application areas. However, the available envelope often limits the power output, and also voltage levels. This paper presents the implementation of an enabling technology for space-restricted energy harvesting: Four highly efficient and fully autonomous power conditioning circuits are presented that are able to operate at deep-sub-milliwatt input power at less than 1 Vpk AC input, and provide a regulated output voltage. The four complete systems, implemented using discrete components, include the power converters, the corresponding ancillary circuits with sub-10 ?W consumption, start-up circuit, and an ultra-lowpower shunt regulator with under-voltage lockout for the management of the accumulated energy. The systems differ in their power converter topology; all are boost rectifier variants that rectify and boost the generator's output in a single stage, that are selected to enable direct comparison between polarity-dependent and -independent, as well as between full-wave and half-wave power converter systems. Experimental results are derived over a range of 200-1200 ?W harvester output power, the system being powered solely by the harvester. Experimental results show overall conversion efficiency, accounting for the quiescent power consumption, as high as 82% at 650 ?W input, which remains in the 65-70% range even at 200 ?W input for the half-wave variant. Harvester utilisation of over 90% is demonstrated in the sub-milliwatt range using full-wave topologies. For the evaluated generator, the full-wave, polarity-dependent boost rectifier offers the best overall system effectiveness, achieving up to 73% of the maximum extractable power.

Szarka, Gyorgy D.; Proynov, Plamen P.; Stark, Bernard H.; Burrow, Stephen G.

2013-05-01

425

Solar power satellite—Life-cycle energy recovery considerations  

Microsoft Academic Search

The construction, in-orbit installation and maintenance of a solar power satellite (SPS) will demand large amounts of energy. As a minimum requirement for an energy effective power satellite it is asked that this amount of energy be recovered. The energy effectiveness in this sense resulting in a positive net energy balance is a prerequisite for a cost-effective power satellite.This paper

J. Blumenberg

1995-01-01

426

Pulse-Power Device as a Tool for High-Energy-Density Plasma Physics and its Applications  

NASA Astrophysics Data System (ADS)

High energy density plasmas driven by pulse power devices are of interest from the point view of their application to formations of extreme conditions. Dense plasmas are produced using pulse-power driven exploding wire discharges in water. Experimental results show that the plasma is tamped and stabilized by the surrounding water and it cylindrically evolves through a strongly coupled state. A shock-heated, high temperature plasma is produced in a compact pulse power device. Results show that extremely strong shock waves can be produced in the device. At low initial pressure condition, the shock Mach number reaches 250 that exceed well a criterion of radiative shock waves.

Horioka, Kazuhiko

427

The power law relation of spiral waves in the Belousov-Zhabotinsky reaction  

NASA Astrophysics Data System (ADS)

The relationship of the period Ts and the wavelength ?s of spiral waves with the control parameters is systematically studied with the Belousov-Zhabotinksy (BZ) reaction in a spatially extended quasi-two-dimensional system. Our experiments indicate that Ts and ?s not only rely on the concentrations of sulfuric acid and sodium bromate, as indicated in the previous work [A. L. Belmonte, Q. Ouyang, and J. M. Flesselles, J. Phys. II 7, 1425 (1997)] but also have strong relation with the concentration of malonic acid (MA). With the influence of the concentration of MA taken into consideration, a revised power law of spiral waves is suggested, which is qualitatively in agreement with early works of numerical simulations and theoretical analysis.

Li, Yan; Bai, Shufeng; Ouyang, Qi

2000-12-01

428

A TIME-INDEPENDENT ENERGY ESTIMATE FOR OUTGOING SCALAR WAVES IN THE KERR GEOMETRY  

Microsoft Academic Search

The Cauchy problem for the scalar wave equation in the Kerr geometry is\\u000aconsidered, with initial data which is smooth and compactly supported outside\\u000athe event horizon. A time-independent energy estimate for the outgoing wave is\\u000aobtained. As an application we estimate the outgoing energy for wave-packet\\u000ainitial data, uniformly as the support of the initial data is shifted to

FELIX FINSTER; JOEL SMOLLER

2008-01-01

429

Reduced local energy as a criterion for the accuracy of Hartree--Fock wave functions  

SciTech Connect

The reduced local energy concept is applied to assess the local accuracy of Hartree--Fock wave functions. The method is illustrated by application to all the Clementi and Roetti's wave functions for the helium atom and to the first row of the helium isoelectronic series. The use of the reduced local energy as a means for improvement of expectation values is discussed. Application to the five term helium wave functions of Clementi and Clementi and Roetti is considered.

King, F.W.; LeGore, M.A.; Kelly, M.K.

1981-07-15

430

Resistor Emulation Approach to Low-Power RF Energy Harvesting  

Microsoft Academic Search

This paper presents an approach and associated circuitry for harvesting near maximum output power from electromagnetic waves in the RF\\/microwave region of the spectrum with variable incident power densities in the range of tens of muW\\/cm2. It is shown that open loop resistor emulation at the input port of a power converter is a suitable solution for tracking the peak

Thurein Paing; Jason Shin; Regan Zane; Zoya Popovic

2008-01-01

431

Artificial optical emissions in the high-latitude thermosphere induced by powerful radio waves: An observational review  

NASA Astrophysics Data System (ADS)

High-power high-frequency radio waves beamed into the ionosphere with O-mode polarization cause plasma turbulence, which can accelerate electrons. These electrons collide with the F-layer neutrals causing artificial optical emissions identical to the natural aurora. The brightest optical emissions are O( 1D) 630 nm, with a threshold of ˜2 eV, and O( 1S) 557.7 nm, with a threshold of ˜4.2 eV. The optical emissions give direct evidence of electron acceleration by plasma turbulence, the non-Maxwellian electron energy spectrum as well as the morphology of the accelerating region with high spatial resolution. HF pumping of the ionosphere also causes bulk electron temperature enhancements, but these alone are not sufficient to explain the optical emissions. We review the published radar and optical observations of high-latitude pump-induced artificial optical emissions and introduce new data.

Kosch, M. J.; Pedersen, T.; Rietveld, M. T.; Gustavsson, B.; Grach, S. M.; Hagfors, T.

432

Conventional and TFPM linear generators for direct-drive wave energy conversion  

Microsoft Academic Search

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

Henk Polinder; Barrie C. Mecrow; Alan G. Jack; Phillip G. Dickinson; Markus A. Mueller

2005-01-01

433

Deflagration wave formed by ion beam. Part 3: With energy of direct fusion reaction  

Microsoft Academic Search

The structure of the deflagration wave which is formed in a target bombarded by an ion beam was analyzed. Stationary deflagration and\\/or detonation waves are formed at the surface of the target in a case in which the reaction energy of direct fusion and\\/or the beam energy deposited in the target are less than a critical value. On the other

K. Niu; T. Abe; M. Tamba

1980-01-01

434

An energy harvesting circuit for self-powered sensors  

Microsoft Academic Search

In this work we present a prototype circuit to harvest energy from radio waves or through magnetic coupling based on a stack of full-wave rectifiers with transistors working on sub-threshold region. This circuit will use as an input a field-to-voltage converter capable of outputting a 200mV waveform and is able to self-start without any other energy sources. The circuit presented

Jorge R. Fernandes; Miguel Martins; Moisés Piedade

2010-01-01

435

Power spectral artifacts in published balloon data and implications regarding saturated gravity wave theories  

NASA Astrophysics Data System (ADS)

There are several theories of atmospheric gravity wave power spectral densities (PSDs) which have been published. These, in turn, have inspired numerous experimental tests. The spectra involved are in the class denoted "stochastic, red noise spectra." This means that most of the power is at the low-frequency end and obeys a power law falloff in going to higher frequency. The present paper describes how some published experimental spectra are flawed by an artifact of spectral analysis which has not heretofore been recognized in the literature. It involves both an amplitude fluctuation enhancement and a coupling between spectral amplitude and slope, and it can be avoided only by stringent control of spectral leakage. Because of "trade-off" considerations every data set, depending on its length and signal characteristics, requires a different method of analysis. It is therefore required that PSD analysis programs must be adjusted and tested to fit each situation. For this purpose a simple method is described to simulate data of known general characteristics for test purposes (to avoid the pitfalls). Since the papers by Nastrom et al. [1997] and de la Torre et al. [1997] have the unfortunate artifact in their analyses, their conclusions regarding saturated gravity wave theories should be reexamined.

Dewan, E. M.; Grossbard, N.

2000-02-01

436

Wind power today: 1999 Wind Energy program highlights  

Microsoft Academic Search

Wind Power Today is an annual publication that provides an overview for the Department of Energy's Wind Energy Program. The purpose of Wind Power Today is to show how DOE's Wind Energy Program supports wind turbine research and deployment in hopes of furthering the advancement of wind technologies that produce clean, low-cost, reliable energy for the 21st century. Content objectives

Weis-Taylor

2000-01-01

437

Wind Power Today: 2000 Wind Energy Program Highlights  

Microsoft Academic Search

Wind Power Today is an annual publication that provides an overview of the U.S. Department of Energy's Wind Energy Program. The purpose of Wind Power Today is to show how DOE's Wind Energy Program supports wind turbine research and deployment in hopes of furthering the advancement of wind technologies that produce clean, low-cost, reliable energy. Content objectives include: educate readers

Weis-Taylor

2001-01-01

438

Market potential of renewable energy powered desalination systems in Greece  

Microsoft Academic Search

The present work analyzes water management strategies based on advanced desalination schemes powered by renewable energy sources. The framework for developing a decision procedure, which monitors water shortage problems and identifies the availability of renewable energy resources to power desalination plants, is presented. Cost of alternative solutions, taking into account energy cost or profits by energy selling to grid, is

D. Voivontas; K. Yannopoulos; K. Rados; A. Zervos; D. Assimacopoulos

1999-01-01

439

Power scaling of high-power optically pumped semiconductor lasers for continuous wave and ultrashort pulse generation  

NASA Astrophysics Data System (ADS)

We report on our research in power scaling OPSL around 1 ?m to exceed 100W per chip by combining a rigorous quantum design of an optimized MQW epitaxial structure, highly accurate and reproducible wafer growth and an efficient thermal management strategy. Recently we have utilized these state-of-the-art optimized OPSL chips to achieve a new record for a mode-locked OPSL with an intra-cavity SESAM. The average output power of the laser in the optimum operation point of mode-locked operation was 5.1W while being pumped with 25W of net pump power. This corresponds to a pulse energy of 3 nJ and a pulse peak power of 3.8 kW.

Laurain, Alexandre; Scheller, Maik; Wang, Tsuei-Lian; Hader, Jorg; Moloney, Jerome V.; Koch, Stephan W.; Heinen, Bernd; Koch, Martin; Kunert, Bernardette; Stolz, Wolfgang

2012-11-01

440

Generation of High-Power Sub-THz Waves in Magnetized Turbulent Electron Beam Plasmas  

NASA Astrophysics Data System (ADS)

Sub-THz radiation can be generated by conversion of plasma waves into electromagnetic (EM) radiation in a plasma with strong Langmuir (LT) turbulence produced via a two-stream instability of a high current relativistic electron beam (REB). Nonlinear plasmon-plasmon merging results in the generation of photons nearby the 2nd harmonic of the plasma frequency 2? p ("2? p -process"). For plasma densities of 1014 - 1015 cm-3, these frequencies are in the range of sub-THz waves at 370-570 GHz. The specific power density of sub-THz-wave emission from plasmas in the multi-mirror magnetic trap GOL-3 (at BINP) during injection of a 10-?s-REB with a current density of about 1 kA/cm2 at plasma densities n e ? 5•1014 cm-3, electron temperatures T e ? 1.5 keV and magnetic induction B ? 4 T was measured to be approx. 1 kW/cm3 in the frequency band around 300 GHz. In the case of a weakly relativistic 100-?s-electron beam (90 keV) with 250 A/cm2 the corresponding results are 700 W/cm3 around 90 GHz with an efficiency of 1-2 % at n e ? 3•1013 cm-3 (total power ? 30 kW). Theoretical investigations show that at a density of n e ? 3•1015 cm-3 and a turbulence level of 5 % the generated sub-THz power can reach ? 1 MW/cm3.

Thumm, M. K. A.; Arzhannikov, A. V.; Astrelin, V. T.; Burdakov, A. V.; Ivanov, I. A.; Kalinin, P. V.; Kandaurov, I. V.; Kurkuchekov, V. V.; Kuznetsov, S. A.; Makarov, M. A.; Mekler, K. I.; Polosatkin, S. V.; Popov, S. A.; Postupaev, V. V.; Rovenskikh, A. F.; Sinitsky, S. L.; Sklyarov, V. F.; Stepanov, V. D.; Trunev, Yu. A.; Timofeev, I. V.; Vyacheslavov, L. N.

2013-02-01

441

Magnetic helicity conservation and inverse energy cascade in electron magnetohydrodynamic wave packets.  

PubMed

Electron magnetohydrodynamics (EMHD) provides a fluidlike description of small-scale magnetized plasmas. An EMHD wave propagates along magnetic field lines. The direction of propagation can be either parallel or antiparallel to the magnetic field lines. We numerically study propagation of three-dimensional (3D) EMHD wave packets moving in one direction. We obtain two major results. (1) Unlike its magnetohydrodynamic (MHD) counterpart, an EMHD wave packet is dispersive. Because of this, EMHD wave packets traveling in one direction create opposite-traveling wave packets via self-interaction and cascade energy to smaller scales. (2) EMHD wave packets traveling in one direction clearly exhibit inverse energy cascade. We find that the latter is due to conservation of magnetic helicity. We compare inverse energy cascade in 3D EMHD turbulence and two-dimensional (2D) hydrodynamic turbulence. PMID:21668138

Cho, Jungyeon

2011-05-13

442

Dispersion of interface waves in sediments with power-law shear speed profiles. I. Exact and approximate analytical results.  

PubMed

In the upper tens of meters of ocean bottom, unconsolidated marine sediments consisting of clay, silt, or fine sand with high porosity are "almost incompressible" in the sense that the shear wave velocity is much smaller than the compressional wave velocity. The shear velocity has very large gradients close to the ocean floor leading to strong coupling of compressional and shear waves in such "soft" sediments. The weak compressibility opens an avenue for developing a theory of elastic wave propagation in continuously stratified soft sediments that fully accounts for the coupling. Elastic waves in soft sediments consist of "fast" waves propagating with velocities close to the compressional velocity and "slow" waves propagating with velocities on the order of the shear velocity. For the slow waves, the theory predicts the existence of surface waves at the ocean-sediment boundary. In the important special case of the power-law depth-dependence of shear rigidity, phase and group velocities of the interface waves are shown to scale as a certain power of frequency. An explicit, exact solution was obtained for the surface waves in sediments characterized by constant density and a linear increase of shear rigidity with depth, that is, for the case of shear speed proportional to the square root of the depth below the sediment-water interface. Asymptotic and perturbation techniques were used to extend the result to more general environments. Theoretical dispersion relations agreed well with numerical simulations and available experimental data and, as demonstrated in a companion paper [D. M. F. Chapman and O. A. Godin, J. Acoust. Soc. Am 110, 1908 (2001)] led to a simple and robust inversion of interface wave travel times for shear velocity profiles in the sediment. PMID:11681370

Godin, O A; Chapman, D M

2001-10-01

443

Design considerations for energy storage power electronics interfaces for high penetration of renewable energy sources  

Microsoft Academic Search

This paper discusses design considerations of power electronics interfaces between renewable energy sources and energy storage. When renewable energy sources—including photovoltaic modules, wind generators, and fuel cells—are used to generate power, there are certain electrical properties of each source that need to be considered for the design of energy storage power electronics interface. In addition, energy storage's charging and discharging

Junseok Song; Ruichen Zhao; Alexis Kwasinski

2011-01-01

444

Air power boosts utility energy supplies  

SciTech Connect

Pumped-hydro storage has been a perennial standby of utilities to meet customers' peak-power demands-but dwindling viable sites and increasing environmental restrictions have dampened new development. Faced with the need to add peaking power to their system at some time in the future, engineers at Central Illinois Public Service are studying a viable alternative to pumped-hydro storage. They are investigating a type of ''pumped-air'' storage system underground - borrowing from a concept first used by northern Arizona Indians almost 1,000 years ago. This method of storing pressurized gas in underground geological anomalies has been used in the U.S. by the natural gas industry to maintain large reserves of gas in depleted oil wells for many years. But storing compressed air for generating power is more recent. Providing the impetus to proceed with this peak-power alternative has been the successful 10-year operating record of the 290 MW HuntorfREAS system in Hamsburg, West Germany, having 195,000 cu in salt-dome caverns that store air under 73 atm pressure. The Compressed Air Energy Storage (CAES) facility, proposed for Pittsfield, Ill., could consist of up to four 50 MW units. It will use a sandstone aquifer underlying the site to store some 650 million cu ft of air injected under about 360 pis pressure (per 50 MW unit). The utility estimates the system can be built for a capital cost of less than $600/kW, using off-the-shelf machinery- which has a turnaround efficiency common to fossil-fuel based, load steam plants.

Longardner, R.L.; Visnecky, A.

1988-07-01

445

High power continuous wave Tm:YAP laser dual-end-pumped by laser diode at 795 nm  

NASA Astrophysics Data System (ADS)

A high power continuous wave diode-pumped Tm:YAP laser at room temperature was presented in this paper. The Tm:YAP crystal with doped concentration of 3 at % for the experiment was c-cut with dimensions of 3 × 3 × 8 mm3. A 795 nm continuous wave laser diode in dual-end-pumped geometry was used to generate 1.94 ?m laser output. At the pump power of 38.9 W, the highest output power reached 12.3 W by use of 15% output coupling, corresponding to optical conversion efficiency was 31.6% and the slope efficiency was 38.2%.

Zhang, Z.; Ruan, N. J.; Zhou, F.; Liu, Z. J.; Xu, L. J.

2011-06-01

446

Measurements of 20 Ghz High-Power Microwaves Output from a Large Diameter Plasma Filled Backward Wave Oscillator.  

National Technical Information Service (NTIS)

A large diameter plasma filled backward wave oscillator (BWO) is investigated experimentally. The parameters of slow wave structure are chosen so that the oscillation frequency is about 20 GHz at 60 keV beam energy. Plasma is produced by the beam and it h...

K. Kurashina W. Kim K. Ogura K. Minami T. Watanabe

1994-01-01

447

Self-consistent Powerful Radio-wave Absorption by Artificial Ionosphere Turbulence  

NASA Astrophysics Data System (ADS)

The numerical simulations of non-linear Schrodinger equation in inhomogeneous plasma layer with pumping and damping are carried out to investigate the influence of self-consistent incident powerful electromagnetic wave absorption in the regions of plasma turbulence excitation to reflection index dynamics. The damping of electromagnetic wave is taking into account by including in the set of equations (Kochetov A.V., Mironov V. A., Terina G.I., Strong Turbulence Effects in Artificially Disturbed Ionosphere, Adv. Space.Res. 2002,vol.29, No.9, p.1369) imaginary part of plasma dielectric permitivity in the vicinity of wave reflection point in the regions with strong electromagnetic field. The large range of damping parameters: threshold, decrement; different amplitude dependence, including hysteretic one, is studied, in particular, in correlation to (V. D. Shapiro, V. I. Shevchenko, Handbook of Plasma Physics, Eds. A. A. Galeev, R N. Sudan, Elsevier, 1984, vol.2, p.119). It is obtained for some regimes that the calculated reflection index dynamics agrees qualitatively to the experimental results (B. Thide, E. N. Sergeev, S. M. Grach,T. B. Leyser, T. D. Carrozi, Competition between Langmuir and upper hybrid turbulence in an HF pumped ionosphere, Phys. Rev. Lett., 2005, vol. 95, no.25, p. 255002). The work is supported in part by Russian Foundation for Basic Research by the grant No. 06-02-17334.

Kochetov, Andrey; Menkova, Uliya; Grach, Savely

448

Photonic all-silicon microsensor for electromagnetic power in the microwave and millimeter-wave range  

NASA Astrophysics Data System (ADS)

A new type of non-perturbing electromagnetic power sensor for microwaves and millimeter-waves, based on the thermo- optical effect in a silicon interferometric etalon cavity is presented. The incident field power is partially dissipated into the all-silicon metal-less etalon, constituting the sensing element of the detector, so causing its temperature increase. This, in turn, induces the intensity modulation of a probe laser beam reflected by the cavity after a multiple beam interference process. The sensing element is directly connected to an optical fiber for remote interrogation, so avoiding the use of perturbing coaxial cables. The performances of such a new class of non-perturbing and wideband probes, in terms of sensitivity and resolution are discussed in detail. The experimental results concerning the characterization of a preliminary prototype sensor are presented and compared with theoretical data. The dependence of the sensor response on the electromagnetic frequency and on the sensing element characteristics is finally discussed.

Rendina, Ivo; Bellucci, Marco; Cocorullo, Giuseppe; Della Corte, Francesco G.; Iodice, Mario

2000-03-01

449

Analysis of power output for piezoelectric energy harvesting systems  

Microsoft Academic Search

Power harvesting refers to the practice of acquiring energy from the environment which would be otherwise wasted and converting it into usable electric energy. Much work has been done on studying the optimal AC power output, while little has considered the AC–DC output. This article investigates the optimal AC–DC power generation for a rectified piezoelectric device. In contrast with estimates

Y C Shu; I C Lien

2006-01-01

450

Power system stability improvement by energy storage type STATCOM  

Microsoft Academic Search

This paper describes an approach to design a damping controller of an energy storage type STATCOM. The energy storage type STATCOM (ESTATCOM) is an advanced flexible AC transmission system (FACTS) device, which controls both reactive and active power injection\\/absorption to the power system. It also provides a better power swing damping. Using a linearized block diagram proposed by the authors,

Kazuhiro Kobayashi; Masuo Goto; Kai Wu; Yasunobu Yokomizu; Toshiro Matsumura

2003-01-01

451

A self-powered mechanical strain energy sensor  

Microsoft Academic Search

With the growing use of sensors in various structural and mechanical systems, the powering and communication of these sensors will become a critical factor. Wireless communication electronics are becoming ubiquitous and with the decreasing electrical power requirements for these circuits it is now feasible to generate power from the conversion of mechanical energy into electrical energy. This paper focuses on

Niell G. Elvin; Alex A. Elvin; Myron Spector

2001-01-01

452

Self-powered systems: a review of energy sources  

Microsoft Academic Search

A range of self-power technologies is reviewed. Self-powered systems are defined as those that operate by harnessing ambient energy present within the environment of the system. As MEMS and smart-material technologies mature, embedded and remote systems become more attractive. Self-power offers a potential for solving the difficult problem of supplying energy to these devices.

P. Glynne-Jones; N. M. White

2001-01-01

453

Power electronics applications in wind energy conversion system: A review  

Microsoft Academic Search

This paper gives a review on the power electronic applications for wind energy conversion systems. Different types of wind energy conversion system (WECS) with different generators and power electronic converters are described, and different technical features are compared. The electrical topologies of WECS with different wind turbines are summarized and the possible uses of power electronic converters with wind farms

R. D. Shukla; R. K. Tripathi; S. Gupta

2010-01-01

454

Renewable energy credit driven wind power growth for system reliability  

Microsoft Academic Search

Environmental concerns over electric power generation from conventional sources has led to widespread public support for renewable energy sources. Governments throughout the world have responded by providing various forms of financial incentives to promote power generation from renewable energy sources. The rapid growth of wind power since the last decade has primarily been driven by governmental subsidies. Long-term growth of

Rajesh Karki

2007-01-01

455

Update '05: ocean wave and tidal power generation projects in San Francisco  

Microsoft Academic Search

In summary, San Francisco's interest in the HydroVenturi approach is due to the value proposition of no moving parts underwater, compared to the underwater turbines of a LaRance river-type saltwater entranement, of a Blue Energy or Verdant Power vertical or horizontal axis-type propeller installation. A technology with no moving parts underwater makes tidal power attractive to San Francisco's well-established environmental

P. O'Donnell

2005-01-01

456

Using Super Capacitor Based Energy Storage to Improve Power Quality in Distributed Power Generation  

Microsoft Academic Search

Distributed power generation will be formed in many weak distribution networks, after renewable energy sources are connected to them. It is very important to increase the reliability and efficiency of using these renewable energy sources. By using DVR (dynamic voltage restorer), the power quality problem in distributed power generation (e.g. voltage fluctuation) can effectively be solved. In this paper, super

Yonghua Chen; J. Van Mierlo; P. Van den Bossche; P. Lataire

2006-01-01

457

PV Output Power Fluctuations Smoothing and Optimum Capacity of Energy Storage System for PV Power Generator  

Microsoft Academic Search

In this paper, an Energy Storage System (ESS) based control method is proposed to reduce the PV output power fluctuations, which in turn will reduce the frequency deviations of the power system introduced by large penetration of PV power. The ESS control model introduced here will maintain the energy storage ratio of the ESS near 50%. This will increase the

Tomonobu Senjyu; Manoj Datta; Atsushi Yona; Toshihisa Funabashi; Chul-Hwan Kim

458

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

SciTech Connect

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

Howes, G. G.; Klein, K. G.; TenBarge, J. M. [Department of Physics and Astronomy, University of Iowa, Iowa City, IA 52242 (United States); Bale, S. D.; Chen, C. H. K.; Salem, C. S. [Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States)

2012-07-01

459

Tropical storm-induced near-inertial internal waves during the Cirene experiment: Energy fluxes and impact on vertical mixing  

NASA Astrophysics Data System (ADS)

AbstractNear-inertial internal <span class="hlt">waves</span> (NIW) excited by storms and cyclones play an essential role in driving turbulent mixing in the thermocline and interior ocean. Storm-induced mixing may be climatically relevant in regions like the thermocline ridge in the southwestern Indian Ocean, where a shallow thermocline and strong high frequency wind activity enhance the impact of internal gravity <span class="hlt">wave</span>-induced mixing on sea surface temperature. The Cirene research cruise in early 2007 collected ship-borne and mooring vertical profiles in this region under the effect of a developing tropical cyclone. In this paper, we characterize the NIW field and the impact of these <span class="hlt">waves</span> on turbulent mixing in the upper ocean. NIW packets were identified down to 1000 m, the maximum depth of the measurements. We estimated an NIW vertical <span class="hlt">energy</span> flux of up to 2.5 mW m-2 within the pycnocline, which represents about 10% of the maximum local wind <span class="hlt">power</span> input. A non-negligible fraction of the wind <span class="hlt">power</span> input is hence potentially available for subsurface mixing. The impact of mixing by internal <span class="hlt">waves</span> on the upper ocean heat budget was estimated from a fine-scale mixing parameterization. During the first leg of the cruise (characterized by little NIW activity), the average heating rate due to mixing was ~0.06 °C month-1 in the thermocline (23-24 kg m-3 isopycnals). During the second leg, characterized by strong NIW <span class="hlt">energy</span> in the thermocline and below, this heating rate increased to 0.42 °C month-1, indicative of increased shear instability along near inertial <span class="hlt">wave</span> <span class="hlt">energy</span> pathways.</p> <div class="credits"> <p class="dwt_author">Cuypers, Y.; Le Vaillant, X.; Bouruet-Aubertot, P.; Vialard, J.; McPhaden, M. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">460</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2012APS..DPPCP8089K"> <span id="translatedtitle">Increasing beam <span class="hlt">power</span> and <span class="hlt">energy</span> with the SBS forward <span class="hlt">energy</span> transfer instability</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The understanding of the exchange of forward going <span class="hlt">power</span> and <span class="hlt">energy</span> between two crossing beams in a plasma [1] is now sufficiently developed that it can be used to enable access to new experimental configurations. The existing models of the process allow the design of beam combiners that will produce higher <span class="hlt">energy</span> in individual beams for new applications in ignition and HED physics. For example the <span class="hlt">Energy</span> Partitioning and <span class="hlt">Energy</span> Coupling (EPEC) [2] program is simulating nuclear events in various environments by delivering <span class="hlt">energy</span> to the center of a chamber through a narrow tube that allows minimal perturbation of the surrounding region. We will describe the design of gas filled targets that will allow a 2x to 5x increase in the <span class="hlt">energy</span> in a single NIF quad to enable higher yield events to be simulated in EPEC. These designs as well as advanced ignition target designs will require models with improved precision to predict their performance accurately. We will also compare the predictions of existing and emerging models of <span class="hlt">wave</span> saturation [3] with the existing experimental data to determine the uncertainty in the models.[4pt] [1] P. Michel Physics of Plasmas 2010.[0pt] [2] K. Fournier, these proceedings[0pt] [3] P. Michel, E. Williams, these proceedings.</p> <div class="credits"> <p class="dwt_author">Kirkwood, R. K.; London, R. A.; Dunlop, W. H.; Michel, P. A.; Williams, E. A.; Fournier, K. B.; Landen, O. L.; MacGowan, B. J.</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-10-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_22");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' href="#">3</a> <a onClick='return showDiv("page_4");' 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onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">461</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.springerlink.com/index/118223p4j3365084.pdf"> <span id="translatedtitle">The <span class="hlt">energy</span> cycle of wind <span class="hlt">waves</span> on the sea surface</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The problems of wind-induced <span class="hlt">waves</span> on the sea surface are considered. To this end, the empirical fetch laws that determine\\u000a variations in the basic periods and heights of <span class="hlt">waves</span> in relation to their fetch are used. The relation between the fetch and\\u000a the physical time is found, as are the dependences of the basic characteristics of <span class="hlt">waves</span> on the time</p> <div class="credits"> <p class="dwt_author">G. S. Golitsyn</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">462</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/18790226"> <span id="translatedtitle">The Properties of Plane-<span class="hlt">wave</span> Scintillation Index Curves for 2D Gaussian and <span class="hlt">Power</span> Law Random Media</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">The plane-<span class="hlt">wave</span> fourth-moment equation is solved numerically for two-dimensional homogeneous random media with Gaussian and <span class="hlt">power</span>-law fluctuation spectra. Scintillation index curves are calculated for scattering strengths ? spanning the range 0·5 to 10. Multiple peaks in the scintillation index curves are found to occur for moderate values of ? (?10) for <span class="hlt">power</span>-law media with <span class="hlt">power</span> indices ? greater than ?2·5.</p> <div class="credits"> <p class="dwt_author">M. C. Cook</p> <p class="dwt_publisher"></p> <p class="publishDate">1991-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">463</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/60177768"> <span id="translatedtitle">Analytical studies on a traveling <span class="hlt">wave</span> direct <span class="hlt">energy</span> converter for D-³He fusion</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Analytical studies on a traveling <span class="hlt">wave</span> direct <span class="hlt">energy</span> converter (TWDEC) for D-³He fueled fusion are carried out. The <span class="hlt">energy</span> of 15 MeV carried by fusion protons is too high to handle with an electrostatic device. The TWDEC controls these high <span class="hlt">energy</span> particles on the base of the principle of a Linac. This traveling <span class="hlt">wave</span> method is discussed and the details</p> <div class="credits"> <p class="dwt_author">L. Y. Syu; Yukihiro Tomita; Hiromu Momota; G. H. Miley</p> <p class="dwt_publisher"></p> <p class="publishDate">1995-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">464</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50720441"> <span id="translatedtitle">Benefits of <span class="hlt">energy</span> storages for wind <span class="hlt">power</span> trading</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In Germany renewable <span class="hlt">energy</span> is paid by law with a high and constant amount wherefore there is no real competition between renewable and conventional <span class="hlt">power</span> plants. This work analyses the possibilities of wind farm operators to take part in an open <span class="hlt">energy</span> market and increase their income with new payment alternatives (e.g. <span class="hlt">energy</span> exchange, control <span class="hlt">power</span>). To secure a steady</p> <div class="credits"> <p class="dwt_author">S. Voller; A.-R. Al-Awaad; J. F. Verstege</p> <p class="dwt_publisher"></p> <p class="publishDate">2008-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">465</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/56406829"> <span id="translatedtitle">Maximum wind <span class="hlt">energy</span> extraction strategies using <span class="hlt">power</span> electronic converters</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This thesis focuses on maximum wind <span class="hlt">energy</span> extraction strategies for achieving the highest <span class="hlt">energy</span> output of variable speed wind turbine <span class="hlt">power</span> generation systems. <span class="hlt">Power</span> electronic converters and controls provide the basic platform to accomplish the research of this thesis in both hardware and software aspects. In order to send wind <span class="hlt">energy</span> to a utility grid, a variable speed wind turbine</p> <div class="credits"> <p class="dwt_author">Quincy Qing Wang</p> <p class="dwt_publisher"></p> <p class="publishDate">2003-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">466</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/50569613"> <span id="translatedtitle">Effects of Wind <span class="hlt">Energy</span> on Thermal <span class="hlt">Power</span> Plants</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Increasing wind <span class="hlt">energy</span> use affects both existing <span class="hlt">power</span> plants as well as future investments in the electricity market. Only a small contribution to total system reliability is added by wind <span class="hlt">energy</span>. Part load operation and lower efficiency caused by the integration of wind <span class="hlt">energy</span> lead to higher specific emissions of thermal <span class="hlt">power</span> plants. Consequently, the reduction of emissions by wind</p> <div class="credits">