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1

Energy analysis of wave and tidal power  

NASA Astrophysics Data System (ADS)

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

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

1980-06-01

2

Energy analysis of wave and tidal power  

Microsoft Academic Search

A methodology is developed for energy analysis of wave and tidal power based on the concepts of energy ratio defined as total output over lifetime of device divided by energy required to build the device or the output of the device over one year divided by energy requirements for one year's operation, and extraction efficiency, defined as total output of

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

1979-01-01

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

Grid power integration technologies for offshore ocean wave energy  

Microsoft Academic Search

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

Tarek Ahmed; Katsumi Nishida; Mutsuo Nakaoka

2010-01-01

5

Wave energy converters and their impact on power systems  

Microsoft Academic Search

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

Henk Polinder; Mattia Scuotto

2005-01-01

6

Ocean wave energy based power plant for Sandwip, Bangladesh  

Microsoft Academic Search

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

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

2012-01-01

7

Maximum Power Point Tracking for Ocean Wave Energy Conversion  

Microsoft Academic Search

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

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

2012-01-01

8

Tapping ocean wave energy for powering gas turbine plants  

Microsoft Academic Search

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

LaStella

1975-01-01

9

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

SciTech Connect

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

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

2012-10-29

10

Wind, Wave, and Tidal Energy Without Power Conditioning  

NASA Technical Reports Server (NTRS)

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

Jones, Jack A.

2013-01-01

11

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

Microsoft Academic Search

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

T. Ahmed; K. Nishida; M. Nakaoka

2010-01-01

12

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

13

Wave Power Systems.  

National Technical Information Service (NTIS)

Ocean wave power is worth investigating as a useable, renewable, alternative energy source. This summary suggests that both Salter cams and Cockerell rafts can be designed to convert wave motion to relative mechanical motion and mechanical forces. Mooring...

N. Doelling

1979-01-01

14

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

15

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

16

Combining Wind and Wave Energy in Offshore Power Plants to Reduce Variability in Electrical Generation  

NASA Astrophysics Data System (ADS)

While wave energy is primarily a wind driven phenomenon, at a particular location and time the energy levels in the wind and waves may be different. The correlation between wind and wave energy is sufficiently weak that combining the two energy sources in a collocated offshore power plant reduces the variability in electrical generation. A preliminary examination of offshore locations along the west coast of the U.S. using buoy data shows two advantages of combining the two energy sources: 1) the number of hours of no power generation in a given year is significantly decreased, which reduces the intermittency of the power plant; 2) a decrease in the variability of the generation curve, which reduces the drops and surges of voltage at the grid interconnection point. The power generation curves for the hypothetical combined wind and wave offshore power plants use atmospheric conditions, wind speed, and wave statistics collected by NOAA buoys, and a common commercial offshore wind turbine model paired with a wave energy convertor in early commercial development in a reasonable array configuration. The hypothetical offshore power plants are located in areas with both a quality wind and wave resource near existing or feasible transmission corridors. Multiple locations along the west coast of the U.S. are used to demonstrate this reduction in power variability and intermittency.

Stoutenburg, E.

2008-12-01

17

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

Microsoft Academic Search

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

Kai Rothenhagen; Marek Jasinski; Marian P. Kazmierkowski

2008-01-01

18

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

19

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

Microsoft Academic Search

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

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

2011-01-01

20

Power extraction from deep ocean waves employing a novel wave energy device  

Microsoft Academic Search

An investigative analysis is presented in which further verification of the Jones Wave Energy extracting system is discussed. The energy produced, based on the novel concept, has been shown to be significantly greater than in previously designed float devices. Full-scale testing was also initiated to illustrate the effects of the float on the wave front.

D. Jones; D. A. Guenther; W. Chiou

1980-01-01

21

The Wave Power Group  

NSDL National Science Digital Library

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

22

Buoys for Wave Power - Methods of the Determination of Energy Production when Limiting the Effect.  

National Technical Information Service (NTIS)

The aim of this investigation was to develop methods for the determination of the production of electric power by a wave energy converter when the height of the waves and the time of the average period are known. A buoy with one coil of a linear synchroni...

J. Forsberg A. Kinnander

1981-01-01

23

Projecting for a Wave Energy Power Plant. Stage B. Tentative Model and Pilot Project.  

National Technical Information Service (NTIS)

Design and feasibility study of a wave energy power plant which could be used in the North Sea. The effects of storm wave forces on the converter and its units were measured in a water tank, and were recorded on video tapes and in table form. Measurements...

1988-01-01

24

Minimising capacitor lifetime failures in power converters for wave energy applications  

Microsoft Academic Search

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

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

2011-01-01

25

On alternative energy sources - Wave power availability in water of finite depth  

NASA Astrophysics Data System (ADS)

The theory of wave height variation due to refraction and friction at the sea bottom is adopted to estimate the amount of mechanical power available at depths ranging from 5 to 25 m, where it seems reasonable to place devices to capture and convert wave energy. The refraction theory is mathematically modelled and the computer program for the power estimation is presented. The evaluation of the wave power available at a location near the Italian coast on the southern Adriatic is presented as an application, and is found to be 3.9 kW/m at the selected point, compared to 6.4 kW/m for deep water in the southern Adriatic. The methods of analytic and numerical bathymetry are used to arrive at the result.

Bergamaschi, S.; Cossalter, V.

1982-03-01

26

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

Microsoft Academic Search

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

Ross Henderson

2006-01-01

27

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

28

Excitation of Langmuir waves by the lower energy cutoff behavior of power-law electrons  

NASA Astrophysics Data System (ADS)

Langmuir waves (LWs), which are believed to play a crucial role in the plasma emission of solar radio bursts, can be excited by streaming instability of energetic electron beams. However, solar hard X-ray observations imply that the energetic flare electrons usually have a power-law energy distribution with a lower energy cutoff. In this paper, we investigate LWs driven by the power-law electrons. The results show that power-law electrons with the steepness cutoff behavior can excite LWs effectively because of the population inversion distribution below the cutoff energy ($E_c$). The growth rate of LWs increases with the steepness index ($\\delta$) and decreases with the power-law index ($\\alpha$). The wave number of the fastest growing LWs ($k\\lambda_D$), decreases with the characteristic velocity of the power-law electrons ($v_{c}=\\sqrt{2E_{c}/m_{e}}$) and increases with the thermal velocity of ambient electrons ($v_T$). This can be helpful for us to understand better the physics of LWs and the dynamics of energetic electron beams in space and astrophysical plasmas.

Tang, Jianfei; Wu, Dejin; Zhao, Guoqing; Chen, Ling; Tan, Chengming

2014-06-01

29

Waves of energy  

SciTech Connect

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

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

1981-05-01

30

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

31

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

32

Ocean wave energy device  

Microsoft Academic Search

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

J. P. LaStella; M. G. Tornabene

1986-01-01

33

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

NASA Astrophysics Data System (ADS)

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

Kamal, Ayman; Lin, Bin; Giurgiutiu, Victor

2013-01-01

34

Exploiting wave power  

Microsoft Academic Search

A survey of proposed wave power systems is presented. Five power conversion devices are studied: (1) the Salter Duck - an asymmetric, cam-shaped device, oscillating about a fixed point, (2) the Cockerell Raft - a structure of rafts hinged together, (3) the air buoy - an asymmetric chamber with trapped water and air, (4) the Kamei - a Japanese device

B. M. Count

1979-01-01

35

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

National Technical Information Service (NTIS)

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 ...

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

2012-01-01

36

Electromagnetic wave energy converter  

NASA Technical Reports Server (NTRS)

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

Bailey, R. L. (inventor)

1973-01-01

37

Ocean wave energy conversion  

Microsoft Academic Search

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.

M. E. McCormick

1981-01-01

38

Waves of energy  

Microsoft Academic Search

Possible means for harnessing the energy contained in ocean waves are considered. Problems associated with the low-grade nature of wave energy and the rate at which wave crests approach are pointed out, and simple devices already in use for the supply of energy to bell buoys, whistle buoys and lighted buoys are noted. Attention is then given to wave energy

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

1981-01-01

39

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

40

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

41

Hydrodynamic simulation of a floating wave energy converter by a U-tube rig for power take-off testing  

Microsoft Academic Search

Floating oscillating-bodies constitute an important class of offshore wave energy converters. The testing of their power take-off equipment (PTO) (high-pressure hydraulics, linear electrical generator or other) under realistically simulated sea conditions is usually regarded as a major task. A laboratory rig, consisting of a U-tube enclosing an oscillating column of water driven by a time-varying air-pressure, was devised to simulate

A. F. de O. Falcão; P. E. R. Pereira; J. C. C. Henriques; L. M. C. Gato

2010-01-01

42

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

43

Direct Mechanical Conversion of Ocean Wave Energy  

Microsoft Academic Search

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

L. Le-Ngoc; A. I. Gardiner

44

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

PubMed

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

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

2011-07-28

45

Proposed electromagnetic wave energy converter  

NASA Technical Reports Server (NTRS)

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

Bailey, R. L.

1973-01-01

46

Ocean wave energy converter  

Microsoft Academic Search

A device for converting the energy of ocean waves into electricity, comprises a buoyant body that floats on the surface of the water and rises and falls with the waves. Fixedly secured to the buoyant body at a depth in the region of still water not affected by the waves, is a bucket wheel or bucket chain which will accordingly

1982-01-01

47

Wave power availability in the NE Atlantic  

Microsoft Academic Search

FOLLOWING Salter's1 proposals for the extraction of energy from sea waves, we are working on the prediction of wave power output from devices situated at favourable coastal sites around the UK. While it is hoped that adequate spectral data from sites closer inshore will become available within the next year or so, the best present data for the North-east Atlantic

Denis Mollison; O. P. BUNEMAN; S. H. SALTER

1976-01-01

48

Transverse-Wave High-Power Tube.  

National Technical Information Service (NTIS)

Research and development work is described on a traveling-wave power amplifier tube employing transverse-wave interaction between the negative synchronous wave and a circuit wave on a balanced structure. The theoretical advantage in this arrangement is th...

C. B. Crumly R. A. Larsen

1968-01-01

49

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

50

Ocean Wave Energy Concepts  

Microsoft Academic Search

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

Michael E. McCormick

1979-01-01

51

Tide following wave power machine  

SciTech Connect

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 is passed an endless belt. The ends of a plurality of blades are secured to the chain in spaced relation completely thereabout. Each sprocket wheels closest to shore is connected to a gear train for transmitting the torque generated by the wave action to a power belt extending along each pier to a transducer located at the shore end of the pier. Means are provided for moving the carriage on the pier on an inclined path in and out from the shore to meet the level of the changing tide so as to continuously generate power throughout the tidal wave.

Murphy, J.T.

1982-09-21

52

Process for conversion of ocean wave energy into electric power and apparatus. [electrochemical gas concentration cell  

Microsoft Academic Search

The apparatus has no moving parts, and uses wave motion to vary the pressure of hydrogen gas in one of the cavities of a two-cavity chamber. The resulting imbalance of pressures in the cavities is relieved by conduction of hydrogen ions through a protonic conductor separating the cavities, and by conduction of electrons through an external circuit, enabling hydrogen gas

R. E. Salomon; S. M. Harding

1979-01-01

53

Wireless power transmission using ultrasonic guided waves  

NASA Astrophysics Data System (ADS)

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

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

2011-07-01

54

Comparison of Direct-Drive Power Takeoff Systems for Ocean Wave Energy Applications  

Microsoft Academic Search

This paper presents a comprehensive power takeoff (PTO) analysis program conducted as a collaborative research effort between Columbia Power Technologies, Inc., Oregon State University (OSU), and the U.S. Navy. Eighteen different direct-drive technologies were evaluated analytically and down-selected to five promising designs. Each of the five prototypes was simulated, modeled in SolidWorks, and built at the 200-W peak level and

Ken Rhinefrank; Alphonse Schacher; Joseph Prudell; Ted K. A. Brekken; Chad Stillinger; John Z. Yen; Steven G. Ernst; Annette von Jouanne; Ean Amon; Robert Paasch; Adam Brown; Alex Yokochi

2012-01-01

55

The Mean Forces Exerted by Waves on Floating or Submerged Bodies with Applications to Sand Bars and Wave Power Machines  

Microsoft Academic Search

Water waves transport both energy and momentum, and any solid body which absorbs or reflects wave energy must absorb or reflect horizontal momentum also. Hence the body is subject to a mean horizontal force. In low waves, the force may be calculated immediately when the incident, reflected and transmitted wave amplitudes are known. For wave power devices the mean force

M. S. Longuet-Higgins

1977-01-01

56

Labrador water-wave energy converter  

Microsoft Academic Search

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

Labrador

1992-01-01

57

Ocean Wave Energy Conversion  

Microsoft Academic Search

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

Jennifer Vining

2005-01-01

58

Key features of wave energy.  

PubMed

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

Rainey, R C T

2012-01-28

59

Laboratory tests of linear electric machines for wave energy applications with emulation of wave energy converters and sea waves  

Microsoft Academic Search

As in other renewable and non-controllable sources of energy, in the case of ocean wave energy the use of electrical linear generator as direct drive power take-off (PTO) in a wave energy converter (WEC) provides several advantages such as improvements in the versatility of control, in the robustness and in the efficiency for a wide range of loads. This paper

Marcos Blanco; Marcos Lafoz; Luis Garcia Tabares

2011-01-01

60

Ocean wave energy converter  

Microsoft Academic Search

This patent describes apparatus for converting the energy of wave motion on the surface of a body of water to electricity comprising: lower structural support means approximately forming edge elements of an equilateral triangle; lower tube receptacles connected to the lower structural support means approximately forming vertex elements of an equilateral triangle; tubular members having upper and lower portions positioned

1987-01-01

61

Wave energy prospect of Bangladesh  

Microsoft Academic Search

Wave energy studies to date have aimed at finding feasible solution of its realistic implementation to the different parts of the world. Bangladesh, which has the longest uninterrupted shoreline and a wide coastal area, should be taken to concern. This paper will briefly reviews the wave energy prospect in Bangladesh and describes about major wave energy plants and its environmental

M. J. Sarker; Imranul Karim; Shirajum Munir

2009-01-01

62

Fluctuation and thermal energy balance for drift-wave turbulence.  

National Technical Information Service (NTIS)

Energy conservation for the drift-wave system is shown to be separated into the wave-energy power balance equation and an ambient thermal-energy transport equation containing the anomalous transport fluxes produced by the fluctuations. The wave energy equ...

C. B. Kim W. Horton B. G. Hong

1990-01-01

63

Multiple traveling wave electromagnetic rotating power supplies: FEM field modeling  

Microsoft Academic Search

Heteropolar electromechanical structures show strong promise as rotating power supplies for electromagnetic launchers with kinetic energy storage and transient magnetic energy storage that can achieve high power densities and small volumes. Both synchronous and asynchronous variants are based on multiple traveling waves of high-amplitude magnetic fields that have multiple velocities. The authors present a finite element formulation of the diffusion

K. T. Hsieh; M. D. Driga

1993-01-01

64

Multiple traveling wave electromagnetic rotating power supplies - FEM field modeling  

Microsoft Academic Search

Heteropolar electromechanical structures show strong promise as rotating power supplies for EM launchers with kinetic energy storage and transient magnetic energy storage that can achieve high power densities and small volumes. Both synchronous and asynchronous variants are based on multiple traveling waves of high-amplitude magnetic fields that have multiple velocities. This paper presents a FEM formulation of the diffusion problem

K. T. Hsieh; M. D. Driga

1993-01-01

65

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

PubMed

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

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

2014-01-01

66

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

PubMed Central

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

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

2014-01-01

67

Large-scale ocean wave energy plant modeling  

Microsoft Academic Search

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

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

2010-01-01

68

HARNESSING OCEAN WAVE ENERGY TO GENERATE ELECTRICITY  

EPA Science Inventory

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

69

OPTIMUM CONTROL OF OSCILLATION OF WAVE-ENERGY CONVERTERS  

Microsoft Academic Search

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

J. Falnes

1993-01-01

70

Dissipation of Rayleigh Wave Energy  

Microsoft Academic Search

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

Eysteinn Tryggavson

1965-01-01

71

Wave energy and intertidal productivity  

Microsoft Academic Search

In the northern Pacific, intertidal zones of the most wave-beaten shores receive more energy from breaking waves than from the sun. Despite severe mortality from winter storms, communities at some wave-beaten sites produce an extraordinary quantity of dry matter per unit area of shore per year. At wave-beaten sites of Tatoosh Island, WA, sea palms, Postelsia palmaeformis, can produce >

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

1987-01-01

72

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

Microsoft Academic Search

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

J. T. Scruggs

2011-01-01

73

Localized transmission of wave energy  

Microsoft Academic Search

Exact solutions of the scalar wave and Maxwell's equations that describe localized transmission of wave energy and their representations will be reviewed briefly. These acoustic (ADEPT) and electromagnetic (EDEPT) directed energy pulse train solutions can be optimized so that they are localized near the direction of propagation and their original amplitude is recovered out to extremely large distances from their

Richard W. Ziolkowski

1989-01-01

74

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

75

A review of wave-energy extraction  

Microsoft Academic Search

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

Johannes Falnes

2007-01-01

76

Economic Factors and Incentives for Ocean Wave Energy Conversion  

Microsoft Academic Search

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

Jennifer G. Vining; Annette Muetze

2009-01-01

77

Economic Factors and Incentives for Ocean Wave Energy Conversion  

Microsoft Academic Search

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

J. G. Vining; A. Muetze

2007-01-01

78

High power millimeter wave source development program  

NASA Technical Reports Server (NTRS)

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

George, T. V.

1989-01-01

79

Average power millimeter wave band travelling wave tube  

Microsoft Academic Search

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

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

2001-01-01

80

Energy storage considerations for a stand-alone wave energy plant  

Microsoft Academic Search

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

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

2005-01-01

81

Offshore and inshore wave energy assessment: Asturias (N Spain)  

Microsoft Academic Search

The offshore and inshore wave energy resource in Asturias (N Spain) is studied using wave buoy data and a hindcast dataset spanning 44 years (1958–2001). Offshore average wave power and annual wave energy values are found to exceed 30 kW\\/m and 250 MWh\\/m, respectively, at 7 of the 11 study sites. This substantial resource is characterised in terms of the sea states

G. Iglesias; R. Carballo

2010-01-01

82

TerraPower's Traveling Wave Reactor  

NASA Astrophysics Data System (ADS)

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

Ellis, Tyler

2011-11-01

83

Interpretation of Wave Energy Spectra.  

National Technical Information Service (NTIS)

Guidelines for interpreting nondirectional wave energy spectra are presented. A simple method is given for using the spectrum to estimate a significant height and period for each major wave train in most sea states. The method allows a more detailed and a...

E. F. Thompson

1980-01-01

84

Ocean wave energy conversion concepts  

Microsoft Academic Search

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

M. E. McCormick

1979-01-01

85

Ocean wave energy converter  

Microsoft Academic Search

A modular assembly of reciprocating electric generators with respective movable floats and a common submerged damper plate and buoyancy chamber produces electricity from wave motion on a body of water.

1980-01-01

86

Tunnel effect wave energy detection  

NASA Technical Reports Server (NTRS)

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

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

1995-01-01

87

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

88

On the dynamics of wave-power devices  

Microsoft Academic Search

The theory of ship dynamics is used to study the performance of a class of wave-power devices. Results are presented for two different devices and a comparison is made between them. The Salter duck and a two-pontoon system, semielliptical in cross section and hinged at its center, constrained to move only in the mode in which energy is absorbed, appear

B. M. Count

1978-01-01

89

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

90

Powerful electromagnetic waves for active environmental research in geospace  

NASA Astrophysics Data System (ADS)

Powerful electromagnetic (EM) waves can exert well-defined influence on the atmosphere, ionosphere, and magnetosphere. These active EM interactions can provide spatiotemporal information on the near-Earth space environment (geospace). Objectives include remote monitoring and controlling of a wide range of parameters of geospace, controlling properties of the ionosphere and magnetosphere, as well as interaction with large-scale natural energy sources. In addition, applications such as mitigation of atmospheric pollutants and solar power satellites are discussed. Studies of EM wave interactions also contribute to the knowledge of anthropogenic effects in the geospace environment, such as the increasing use of EM radiation.

Leyser, T. B.; Wong, A. Y.

2009-03-01

91

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

92

Wave power experiments at Loch Ness  

Microsoft Academic Search

The duck wave energy generator was proposed by Salter in 1974 and subsequent work has established the device as a practical solution to the problem of extracting energy from seawaves. This paper discusses the engineering aspects of testing a 1\\/10th scale model of a Salter duck device on an inland water test site on Loch Ness in Scotland. Consideration is

N. W. Bellamy

1979-01-01

93

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

94

The Dynamics of Wave Energy  

Microsoft Academic Search

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

John Ringwood

95

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

96

Ionospheric modification by high power radio waves  

Microsoft Academic Search

Investigations using powerful, high frequency (HF) radio waves to temporarily modify the ionosphere are reviewed. Studies of the natural upper atmosphere have been conducted using these controlled, active experiments by observing the ionospheric response to HF induced perturbations. Other basic physics investigations have examined the ionosphere and its properties and behavior as a plasma. Topics examined include ionospheric heating, parametric

L. M. Duncan; W. E. Gordon

1982-01-01

97

Frequency response analysis of ocean wave energy converter  

Microsoft Academic Search

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

M. Masubuchi; R. Kawatani

1981-01-01

98

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

Microsoft Academic Search

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

O. Siddiqui; R. Bedard

2005-01-01

99

High power millimeter wave ECRH source needs for fusion program  

SciTech Connect

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

Not Available

1984-06-01

100

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

PubMed

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

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

2012-01-28

101

Wave energy transformation on natural profiles  

Microsoft Academic Search

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

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

1996-01-01

102

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

Microsoft Academic Search

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

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

2006-01-01

103

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

104

Ultrasound acoustic wave energy transfer and harvesting  

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

105

Evaluation of Ocean Wave Energy. Calculated Energy Production.  

National Technical Information Service (NTIS)

An evaluation of ocean wave energy as a supplementary energy source in Norway has been performed for the Norwegian Department of Energy. The expected energy production has been calculated for 4 different wave energy converts, located at three different po...

O. Malmo

1981-01-01

106

Constructing the frequency and wave normal distribution of whistler-mode wave power  

NASA Astrophysics Data System (ADS)

We introduce a new methodology that allows the construction of wave frequency distributions due to growing incoherent whistler-mode waves in the magnetosphere. The technique combines the equations of geometric optics (i.e., raytracing) with the equation of transfer of radiation in an anisotropic lossy medium to obtain spectral energy density as a function of frequency and wavenormal angle. We describe the method in detail and then demonstrate how it could be used in an idealized magnetosphere during quiet geomagnetic conditions. For a specific set of plasma conditions, we predict that the wave power peaks off the equator at ˜15° magnetic latitude. The new calculations predict that wave power as a function of frequency can be adequately described using a Gaussian function, but as a function of wavenormal angle, it more closely resembles a skew normal distribution. The technique described in this paper is the first known estimate of the parallel and oblique incoherent wave spectrum as a result of growing whistler-mode waves and provides a means to incorporate self-consistent wave-particle interactions in a kinetic model of the magnetosphere over a large volume.

Watt, C. E. J.; Degeling, A. W.; Rankin, R.

2013-05-01

107

Transverse Flux Permanent Magnet Generator for Ocean Wave Energy Conversion  

Microsoft Academic Search

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

José Lima; Anabela Pronto; Mário Ventim Neves

2011-01-01

108

Integrating Wave Power into the Electricity Supply System.  

National Technical Information Service (NTIS)

As a source of electricity wave power has two distinctive features, one favorable - its good seasonal correlation with demand - and one unfavorable - its unpredictability. Data on wave-power was combined with a previously developed model of seasonal and d...

D. Vimukta

1977-01-01

109

Ocean wave energy converting vessel  

Microsoft Academic Search

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

Boyce

1986-01-01

110

IEEE Power and Energy  

NSDL National Science Digital Library

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

2003-01-01

111

Localized transmission of wave energy  

NASA Astrophysics Data System (ADS)

Exact solutions of the scalar wave and Maxwell's equations that describe localized transmission of wave energy and their representations will be reviewed briefly. These acoustic (ADEPT) and electromagnetic (EDEPT) directed energy pulse train solutions can be optimized so that they are localized near the direction of propagation and their original amplitude is recovered out to extremely large distances from their initial location. Pulses with these very desirable localized transmission characteristics have a number of potential applications in the areas of directed energy weapons, secure communications, and remote sensing. The feasibility of launching an ADEPT from an array of acoustic transducers has been tested experimentally. As will be shown, excellent agreement between theoretical and experimental results was obtained.

Ziolkowski, Richard W.

1989-07-01

112

Electron Acceleration by High Power Radio Waves in the Ionosphere  

NASA Astrophysics Data System (ADS)

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

Bernhardt, Paul

2012-10-01

113

Wave energy transmission system concepts for linear generator arrays  

Microsoft Academic Search

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

Karin Thorburn; Hans Bernhoff; Mats Leijon

2004-01-01

114

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

115

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

PubMed

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

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

2012-01-01

116

Body Wave Energy Investigations in Ambient Seismic Noise  

NASA Astrophysics Data System (ADS)

The microseismic frequency band contains a large amount of coherent energy, which has generated much interest recently because of its use in surface wave tomography as well as its apparent link to temporal changes in ocean wave behavior. Although the dominant component of this energy travels as surface waves, body waves also contribute a significant portion at slightly higher frequencies. The surface wave noise appears to be generated by ocean wave interaction along the coastline, however, several studies have indicated that the body wave energy may originate from the deep ocean suggesting the possibility of different mechanisms for the generation of surface and body wave noise. Further exploration of the nature of body wave noise is necessary to better understand how and where it is generated, and what additional information we might gain from it. We investigate source locations of body wave noise generation using a back-projection technique similar to those used to study earthquake rupture properties. We use data from two arrays, YKA and ILAR, both of which are small aperture seismic arrays of the International Monitoring System. Array analysis provides a powerful tool for placing constraints on the direction and mode of incoming coherent energy. We examine a year's worth of data in 10 second time windows and back-project each window to a grid of potential source locations to determine the time and location with the greatest beam power. Preliminary results from YKA show a strong seasonal signal. Source locations from January to May concentrated in an area in the middle of the northern Pacific, consistent with independent results from a traditional frequency-wavenumber analysis and supportive of the possibility of a persistent deep ocean generation for microseismic P-waves. From June to September, source locations shift to the northwestern Atlantic, while October to November shows a more diffuse area of sources. We will compare our results with satellite observations of significant wave height as well as the wave-wave interaction parameter from reanalysis models.

Pyle, M. L.; Koper, K. D.

2011-12-01

117

Optimal switching control of an absorber ocean wave energy device  

Microsoft Academic Search

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

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

2008-01-01

118

Wave and tide powered generation apparatus  

SciTech Connect

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

Suggs, L. F.

1985-09-03

119

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

120

Evaluation of global wave energy resource  

Microsoft Academic Search

In this work, we make use of two wave databases, satellite measurements and numerical modeling, to develop a methodology to obtain reliable estimates of the spatial and temporal variability of global wave energy resources. As a result, the global distribution of wave energy resources has been evaluated (since 1948) at a global scale analyzing its variability in time (within seasons

B. G. Reguero; C. Vidal; M. Menendez; F. J. Mendez; R. Minguez; I. Losada

2011-01-01

121

Sensitivity of wave energy to climate change  

Microsoft Academic Search

Wave energy will have a key role in meeting renewable energy targets en route to a low carbon economy. However, in common with other renewables, it may be sensitive to changes in climate resulting from rising carbon emissions. Changes in wind patterns are widely anticipated, and this will ultimately alter wave regimes. Indeed, evidence indicates that wave heights have been

Gareth P. Harrison; A. Robin Wallace

2005-01-01

122

Return period and risk calculations for ocean wave energy applications  

Microsoft Academic Search

The statistical behavior of wave energy at a site strongly depends on the wave characteristics. Wave energy converters fail to produce energy when there are no sufficiently available wave heights. Hence, evaluation of return periods and risk values of the minimum wave height becomes important for wave energy studies. A time index representing the minimum wave height is proposed here

Mehmet Özger; Zekai ?en

2008-01-01

123

Optimisation of wave energy extraction with the Archimedes Wave Swing  

Microsoft Academic Search

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

Duarte Valério; Pedro Beirão; José Sá da Costa

2007-01-01

124

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

125

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

PubMed

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

Bose, N; Lien, J

1990-06-22

126

Ocean energy-waves, currents, and tides  

Microsoft Academic Search

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

J. Miles; B. Shelpuk

1981-01-01

127

High power microwave generation by relativistic backward wave oscillator  

Microsoft Academic Search

In this paper, a high power relativistic backward wave oscillator (BWO) experiment is reported. A 230 kV, 2 kA, and 150 ns relativistic electron beam source is developed using a Marx generator. The beam is then injected into a hollow rippled wall metallic cylindrical tube that forms a slow wave structure (SWS). A BWO is a slow wave structure in

Lalit Gupta; Y. Choyal; Prasad Deshpande; K. P. Maheshwari; K. C. Mittal

2008-01-01

128

Tuning resonant interaction of orthogonally polarized solitons and dispersive waves with the soliton power.  

PubMed

We demonstrate that the relatively small power induced changes in the soliton wavenumber comparable with splitting of the effective indexes of the orthogonally polarized waveguide modes result in significant changes of the efficiency of the interaction between solitons and dispersive waves and can be used to control energy transfer between the soliton and newly generated waves and to delay or accelerate solitons. PMID:24921797

Yulin, A V; Gorjão, L R; Driben, R; Skryabin, D V

2014-05-01

129

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

130

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

NASA Astrophysics Data System (ADS)

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

Black, C.; Haller, M. C.

2013-12-01

131

A high-power, traveling wave tube amplifier  

SciTech Connect

High-power X-band traveling wave tube amplifiers (TWT's) have been fabricated and tested. The tubes have gains ranging from 13 to 35 dB at 8.76 GHz and output powers ranging from 3 to 100 MW. The amplifiers are driven by the interaction of a slow space-charge wave, propagating on an electron beam, with an electromagnetic wave supported by the structure. The electron beam, which is produced from a magnetic-field-immersed field-emission cathode, has an energy of 850 keV, a current in the 1-kA range, and a pulse duration of 100 ns. The amplifiers are designed to operate as narrow-band devices in the TM{sub 01} mode. In this paper the authors report on the amplifier characteristics and compare their performance with those calculated using conventional TWT theory. The scaling of the gain and bandwidth with the beam current are approximately as expected from theory, but the absolute magnitude of the gain is somewhat greater than expected.

Shiffler, D.; Nation, J.A.; Kerslick, G.S. (Cornell Univ., Ithaca, NY (USA). Lab. of Plasma Studies)

1990-06-01

132

Fundamental research on oscillating water column wave power absorbers  

Microsoft Academic Search

An oscillating water column (OWC) wave power absorber is one of the most promising devices, as well as the Salter Duck and the Clam. This paper presents a simple prediction method, in which the equivalent floating body approximation is used, for absorbing wave power characteristics of an oscillating water column device. The effects of the compressibility of air and inertia

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

1985-01-01

133

Millimeter wave materials processing in Japan by high power gyrotron  

Microsoft Academic Search

Firstly, innovative materials processing in Japan using high power mm-wave radiation of gyrotrons is reviewed briefly. Secondly extensive research results conducted on ceramics sintering and modification by 28 GHz mm-wave is described with emphasis on the unique characteristics inherent to mm-wave irradiation to materials. In the mm-wave processing of bulk materials low temperature sintering of Si3N4 with Yb2O3 and Al2O3

S. Miyake

2002-01-01

134

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

135

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

136

Transmission of wave energy in curved ducts  

NASA Technical Reports Server (NTRS)

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

Rostafinski, W.

1973-01-01

137

Ocean Energy-Waves, Currents, and Tides.  

National Technical Information Service (NTIS)

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

J. Miles B. Shelpuk

1981-01-01

138

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

139

Energy spectra of turbulent sound waves  

Microsoft Academic Search

The dynamics of an irrotational compressible flow is considered in several space dimensions both theoretically and by numerical experiments. First we derive the nonlinear scalar wave equation (9) describing sound waves of small amplitude and small dissipation. The associated weak-turbulence equations in the limit of zero dissipation are solved by exact stationary power laws for the spectrum. But the numerical

Klaus Elsässer; Hans Schamel

1976-01-01

140

A New Solar Powering Mechanism: Could Driven Waves be the Key to the Solar Puzzle?  

NASA Astrophysics Data System (ADS)

The ultimate source of energy for both coronal heating and solar wind acceleration is known, but the exact nature of the photospheric energy transport and deposition is still a puzzle. Using the driven wave formalism, the author and his collaborators showed an existence of waves which to date have not been widely considered. Using the same formalism to characterize the solar plasma at various distances from the Sun, we show how driven waves can effectively deposit the energy on particles, how these waves can power the solar wind, and discuss the role driven waves can play in the generation of the observed solar wind turbulence spectra. This paper provides overview of the driven wave formalism to address the question: Could this overlooked mechanism be the key to the longstanding question of the solar physics?

Kaghashvili, E. K.

2013-12-01

141

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

142

Optimal control of the magnetohydrodynamic ocean wave energy converter: theory  

Microsoft Academic Search

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

Dmitry A. Altshuller; Robert A. Koslover

2005-01-01

143

A low-cost float method of harnessing wave energy  

Microsoft Academic Search

The author proposes in this paper a low-cost and simple method of harnessing wave energy that should enable coastal regions to be self-sufficient in electric power. The method is eminently applicable to India and such developing countries, being simple and involving a small capital investment. The method was evolved after study of the Indian West Coast fronting the Arabian Sea,

1983-01-01

144

Fundamental research on oscillating water column wave power absorbers  

SciTech Connect

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

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

1985-03-01

145

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

146

A new controller for efficient wave power generation  

Microsoft Academic Search

Based on the stator current control of induction machine, a new current control scheme is developed for making the peak power to average power ratio of the wave power feeding in to the mains around unity. The proposed scheme is realised using an AC voltage controller. The induction machine operates both in motor and generating modes. Both simulation and test

ALLABAKSH L. NAIKODI; G. Sridhara Rao

1995-01-01

147

Future Potential of Wave Power in the United States.  

National Technical Information Service (NTIS)

The theoretical ocean wave energy resource potential exceeds 50% of the annual domestic energy demand of the United States, is located close to coastal population centers, and, although variable in nature, may be more consistent and predictable than some ...

D. Heimiller J. Epler K. Eurek M. Hand

2012-01-01

148

Wave power CTH. Final report. (Vaagkraft CTH. Slutrapport).  

National Technical Information Service (NTIS)

Wave energy research, carried out at the Dept. of Hydraulics, Chalmers University of Technology, during the period 1988.12.01 -1989.11.30, is presented. The research has been focused partly on a general survey of the international wave energy research dur...

L. Berggren M. Johansson L. Bergdahl

1990-01-01

149

High power electronic scanning millimeter-wave radar system design  

Microsoft Academic Search

Remote Sensing Solutions, Inc has received NASA funding to design a prototype millimeter-wave radar system that will lead to future generations of large aperture space-borne electronic scanning radars. A scanning millimeter-wave radar is critical tool for improving the remote sensing of the Earth and other bodies in our solar system. Low power solid-state scanning millimeter-wave radar systems cannot provide the

Stephen M. Sekelsky; James Carswell

2006-01-01

150

78 FR 40132 - Wave Energy Converter Prize Administration Webinar  

Federal Register 2010, 2011, 2012, 2013

...OF ENERGY Office of Energy Efficiency and Renewable Energy Wave Energy Converter Prize Administration Webinar AGENCY: Office...Opportunity Announcement (FOA), tentatively titled, ``Wave Energy Converter Prize Administration''. The Office...

2013-07-03

151

Generation of very low frequency beat waves from power converters  

Microsoft Academic Search

In the course of investigation of the EMI emissions from DC\\/AC power converters controlling synchronous machines in a hybrid electric vehicle (HEV), very low frequency beat waves were picked up in the common mode currents on the AC link. The beat wave patterns have maxima which could be more than ten percent of the phase current amplitude and at frequencies

Mathias Enohnyaket

2009-01-01

152

Energy density of relic gravity waves from inflation  

SciTech Connect

We evaluate both the spectral energy density and the total energy density for relic gravity waves produced during the transition from an early inflationary phase to a matter-dominated Friedmann-Robertson-Walker-type expansion: {ital a}{similar to}{ital t}{sup {ital c}} ({ital c}{lt}1). We find that for power-law inflation the spectral energy density for gravity waves has more power on larger scales than for purely exponential inflation. Evaluating the energy density of created massless particles (both gravitons and massless scalars) we find that in the case of exponential inflation the ratio of the density of created particles to the total density of matter is a constant, if {ital c}{ge}1/2. This unusual behavior is a consequence of the fact that the equation of state for created particles mimics the equation of state for matter driving the expansion of the Universe. As a result, self-consistent solutions of the Einstein equations can be found, in which the expansion of the Universe is sustained solely by the ongoing production of massless particles, so that {ital G}{sub {mu}{nu}}=8{pi}{ital G}{l angle}{ital T}{sub {mu}{nu}}{r angle}. In the case of power-law and quasiexponential inflation we find that the ratio of the energy density of gravity waves to the background matter density increases with time, as gravity waves with longer wavelengths and larger amplitudes enter the horizon at successively later epochs. This could lead to the energy density of gravity waves becoming comparable to the energy density of matter at late times, if inflation commenced at Planckian energies.

Sahni, V. (Canadian Institute for Theoretical Astrophysics, University of Toronto, Toronto, Ontario (Canada))

1990-07-15

153

Energy and momentum of cylindrical gravitational waves  

Microsoft Academic Search

It was found manyyears ago that in cylindrical polar coordinates the energy and momentum densities of gravitational waves, calculated with the help of a pseudo-tensor, vanish. However, using cartesian coordinates, one finds them to be finite and reasonable.

Nathan Rosen; K. S. Virbhadra

1993-01-01

154

Wave energy converters. Generic technical evaluation study.  

National Technical Information Service (NTIS)

The objectives of this B-project under the DG XII Initiative concerning Preliminary Actions in Wave Energy Research and Development (under the auspices of the Commission of the European Communities) are to assess the theoretical, technical and economic un...

G. P. Thomas K. Nielsen P. Randloev S. S. Salter W. C. Beattie

1993-01-01

155

Gyro-amplifiers for high power millimeter wave radar  

Microsoft Academic Search

Summary form only given. Over the past several years there has been a concerted effort within the US to develop millimeter wave gyro-amplifiers for high-power millimeter wave radar. Efforts have been carried out by a number of researchers at both Ka- and W-bands. These efforts have culminated in the successful integration of a high-average-power W-band gyro-klystron into the NRL WARLOC

B. G. Danly

2002-01-01

156

Self-similar relativistic blast waves with energy injection  

NASA Astrophysics Data System (ADS)

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

van Eerten, Hendrik

2014-08-01

157

Stabilized High Power Laser for Advanced Gravitational Wave Detectors  

NASA Astrophysics Data System (ADS)

Second generation gravitational wave detectors require high power lasers with several 100W of output power and with very low temporal and spatial fluctuations. In this paper we discuss possible setups to achieve high laser power and describe a 200W prestabilized laser system (PSL). The PSL noise requirements for advanced gravitational wave detectors will be discussed in general and the stabilization scheme proposed for the Advanced LIGO PSL will be described. Special emphasis will be given to the most demanding power stabilization requiremets and new results (RIN <= 4×10-9/surdHz) will be presented.

Willke, B.; Danzmann, K.; Fallnich, C.; Frede, M.; Heurs, M.; King, P.; Kracht, D.; Kwee, P.; Savage, R.; Seifert, F.; Wilhelm, R.

2006-03-01

158

Multistable chain for ocean wave vibration energy harvesting  

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

159

Ocean Wave Energy Conversion - A Survey  

Microsoft Academic Search

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

A. Muetze; J. G. Vining

2006-01-01

160

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

161

WARLOC: a high-power millimeter-wave radar  

Microsoft Academic Search

A high-power, coherent, W-band (94 GHz) millimeter-wave radar has been developed at the Naval Research Laboratory. The radar employs a 100 kW peak power, 10 kW average power gyroklystron as the final power amplifier, an overmoded transmission line system, and a quasioptical duplexer, together with a 6 foot Cassegrain antenna, a four-channel receiver, and state-of-the-art signal processing. Developed as a

B. G. Danly; J. Cheung; V. Gregers-Hansen; G. Linde; M. Ngo

2002-01-01

162

Backward-Wave Oscillation Suppression in High-Power Broadband Helix Traveling-Wave Tubes  

Microsoft Academic Search

The effects of the attenuator and the pitch step and taper on suppressing the backward-wave oscillation (BWO) in high-power broadband helix traveling-wave tubes (TWTs) are analyzed by a nonlinear 1-D beam-wave interaction theory in which the effects of the variation of the angular velocity of the macroparticles along the length of circuit are considered. It is found that the incorporation

Yu Lu Hu; Zhong Hai Yang; Jian Qing Li; Bin Li

2011-01-01

163

Direct Drive Wave Energy Buoy – 33rd scale experiment  

SciTech Connect

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

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

2013-07-29

164

0.14THz high power millimeter wave generation from a relativistic surface wave oscillator  

Microsoft Academic Search

In this paper, a novel overmoded surface wave oscillator (SWO) is proposed, and it could deliver an output power around 40 MW under the condition of 370 kV incident voltage at frequency of about 0.14 THz. The characteristics of surface wave and point operation are crucial to avoid the mode competition. Effects of various operating parameters on the device behavior

Hai Zhang; Jianguo Wang; Changjiang Tong

2008-01-01

165

Pulse shortening in a high power backward wave oscillator  

Microsoft Academic Search

Summary form only given. This paper describes an experimental and theoretical investigation specifically oriented to revealing the various physical phenomena responsible for pulse shortening in a high power backward wave oscillator (BWO). Pulse shortening is common among all long-pulse, electron beam-driven, high power microwave sources. Therefore, data obtained in the course of these investigations should be applicable to a variety

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

1996-01-01

166

Neural network based estimation of power electronic waves  

Microsoft Academic Search

Artificial neural network techniques are indicating a lot of promise for application in power electronic systems. So far, these applications are mainly confined in the control identification and diagnostic problems, but the application in estimation is fairly new. The paper explores the application of neural network for estimation of power electronic waveforms. The distorted line current waves in single-phase thyristor

Min-Huei Kim; M. Godoy Sim; Bimal K. Bose

1995-01-01

167

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.

168

Energy 101: Concentrating Solar Power  

ScienceCinema

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

None

2013-05-29

169

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

170

Governmental Regulation of Ocean Wave Energy Converter Installations  

Microsoft Academic Search

Interest in ocean energy converter technology has increased with the revival of renewable energy awareness. To date, ocean current energy converters have been implemented with relatively mature technology when compared to wave energy converters. Despite the novelty of wave energy, several commercial wave energy projects have recently been undertaken. However, this process has not been accompanied by the development of

J. G. Vining; A. Muetze

2007-01-01

171

A 50-75 Gc power backward-wave oscillator  

Microsoft Academic Search

A power backward-wave oscillator for a minimum power output of one watt c.w. over the 50-75 Gc band has been designed and tested. Maximum powers of 2.5 watts c. w. and approximately 20 watts peak have been measured with this tube operating in a permanent magnet. This tube uses an electron gun having an area convergence of 100:1 and a

R. T. Schumacher

1962-01-01

172

A 100 Gc high-power backward-wave oscillator  

Microsoft Academic Search

A pulsed backward-wave oscillator designed to produce 100 kw peak power and 1000 watts of average power at 100 Gc has been constructed. The tube utilizes a disc-loaded waveguide circuit and a perveance 0.125 × 10-6electron gun having an area convergence ratio of 900 to 1. The electron beam has a power density of 280 mega-watts\\/cm2and a current density of

J. W. Sedin; K. W. Slocum; M. V. Purnell

1963-01-01

173

Analysis of the power capacity of overmoded slow wave structures  

SciTech Connect

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

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

2013-07-15

174

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

Microsoft Academic Search

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

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

2006-01-01

175

DESALINATION WITH WIND AND WAVE POWER  

Microsoft Academic Search

Seawater desalination can be an attractive alternative to ensure a secure source of water. However, the energy requirements\\u000a for that process are high and can be a problem, mainly in isolated areas. Renewable energies are the best way to supply the\\u000a energy needs, because can be available near the desalination plants and avoid environmental\\/availability problems associated\\u000a with fossil fuels. In

ANÍBAL T. DE ALMEIDA; PEDRO S. MOURA

176

Electromagnetic wave energy conversion research  

NASA Technical Reports Server (NTRS)

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

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

1975-01-01

177

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.

178

High Power Mid Wave Infrared Semiconductor Lasers.  

National Technical Information Service (NTIS)

This project identifies key challenges for the development of high- power electrically injected MWIR laser arrays using 111-V antimonide based materials. In this approach, InGaSb quantum wells are grown on metamorphic layers on a GaSb or GaAs substrate. D...

R. Dawson S. Krishna

2006-01-01

179

Wave-actuated power take-off device for electricity generation  

SciTech Connect

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

Chertok, Allan

2013-01-31

180

Joining of ceramic tubes using a high-power 83GHz Millimeter-wave beam  

Microsoft Academic Search

High purity, high density alumina tubes have been successfully joined using a high-power millimeter-wave beam. This technique exploits the use of the beam-forming capability of an 83-GHz gyrotron-based system allowing the deposition of energy into a narrow region surrounding the joint area with minimal heating (<100°C) of the metal fixturing (a modified microlathe). The power deposition and heating was modeled

Ralph W. Bruce; Robert L. Bruce; Arne W. Fliflet; Manfred Kahn; Steven H. Gold; Allen K. Kinkead; M. A. Imam

2005-01-01

181

Chromospheric alfvenic waves strong enough to power the solar wind.  

PubMed

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

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

2007-12-01

182

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

National Technical Information Service (NTIS)

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 an...

M. Previsic

2010-01-01

183

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

184

High-power microwave attenuator employing slow wave structure  

NASA Astrophysics Data System (ADS)

Using present pulsed microwave amplifier, we can obtain RF peak power beyond one hundred MW. However, it is not easy to test such a high-power RF. To overcome this difficulty we developed a high-power microwave attenuator employing a slow wave structure. For example, the output power of RF pulse compressor for present electron linear accelerator reaches a few hundreds MW RF power, but the existing dummy loads can absorb only a few tens MW of RF power. The attenuator we developed has a kind of periodic structure and is made of metal only. We operated this attenuator using a high-power RF source, and found that it could be operated fewer than 50 pps RF output at 40 MW, 2.5 ?s or 100 MW, 0.5 ?s.

Yoshida, Mitsuhiro; Matsumoto, Hiroshi; Shintake, Tsumoru; Nishiyama, Koji; Miura, Sadao

2012-11-01

185

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

186

Power and energy  

Microsoft Academic Search

The design and manufacture of electric power equipment, the one electrotechnology in which Europe could gain worldwide dominance by the end of the century, is examined. All three power-equipment categories-generation, transmission, and distribution-are involved. Europeans already lead in the production of extra-high-voltage (EHV) circuit breakers, high-voltage, direct-current (HVDC) equipment, and hydroelectric turbines. More recently, they have entered world markets for

G. Zorpette

1990-01-01

187

Fabrication of a High Power Resonant WaveGuide Window  

Microsoft Academic Search

The inability of present wave-guide pre-TR and TR tube windows to withstand high transmitter power necessitates improved window design if 3000-megacycle radar systems are to continue using the conventional band pass TR protective device. The fabrication of a glass window with a loaded Q of four is described and operational tests at high line power are discussed. This construction permits

E. V. Edwards; K. Garoff

1950-01-01

188

Negative energy waves in magnetic flux tubes  

Microsoft Academic Search

The properties of oscillation of a magnetic flux tube in the presence of a shear flow of matter along its axis were studied. The presence of flows is shown to cause a number of new effects: the appearance of negative energy waves, reversal of the sign of radiative damping, the development of explosive instability at the nonlinear stage, and the

M. P. Ryutova

1988-01-01

189

Negative Energy Waves in Magnetic Flux Tubes.  

National Technical Information Service (NTIS)

The properties of oscillation of a magnetic flux tube in the presence of a shear flow of matter along its axis have been studied. The presence of flows is shown to cause a number of new effects: the appearance of negative energy waves, reversal of the sig...

M. P. Ryutova

1988-01-01

190

Sea and ocean wave energy converter  

Microsoft Academic Search

A device for converting the energy of sea and ocean waves is described, including a turbogenerator connected by means of pipelines to input and output elements on which there are mounted ballast systems and stabilizers. The input and output elements are designed as a high pressure vessel and a low pressure vessel, respectively, each having a gas cushion. A high

Nedyalkov

1982-01-01

191

Assembly for harnessing wave and tide energy  

SciTech Connect

An assembly for harnessing wave and tide energy, is described comprising: (a) an elongated float means for floating on the surface of a body of water having waves moving therealong, (b) support means freely pivotally connected to the float means for maintaining the float means parallel to the surface of the water, (c) the support means being effective to maintain the float means with its longest dimension disposed in a direction parallel to the length of the waves moving along the surface of the body of the water, (d) transmission means including two parallel transmission shafts responsive to the support means as the float means moves up and down with the movement of the waves to produce a rotational movement from which energy may be derived, (e) the support means including two arm members each having an outer free end pivotally connected to the float means and having counterweight means located at the other inner end thereof which counterweight means extends to an opposing side of the transmission shaft with respect to the corresponding float means to neutralize a portion of the weight of the float means and arm member, (f) base structures fixedly disposed on the bottom of the body of water with the transmission means located on the base structures that are laterally displaced with respect to each other and extend outwardly from a shore station into the body of water in a direction transverse to the length of the waves moving along the surface of the body of water.

Vides, M.M.

1988-01-12

192

A high power travelling wave tube (TWT) amplifier  

Microsoft Academic Search

Preliminary results are reported on the design and performance of a high power traveling wave tube amplifier. The amplifier is designed to work in the TM01 mode of a cylindrical waveguide and to operate in X band. The signal from a 250 kW magnetron is used as the input source for the amplifier. Details are presented of the amplifier design,

John A. Nation; Donald Shiffler

1988-01-01

193

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

194

Power Technologies Energy Data Book  

DOE Data Explorer

In 2002, the Strategic Energy Analysis Center of the National Renewable Energy Laboratory (NREL) developed the first version of the Power Technologies Energy Data Book for DOE's Office of Power Technologies. The main purpose of the data book is to compile, in one central document, a comprehensive set of data about power technologies from diverse sources. The need for policy makers and analysts to be well-informed about power technologies suggests the need for a publication that includes a diverse, yet focused, set of data about power technologies. The latest edition of the PTEDB features Geographic Information System (GIS) maps. One set of maps shows the natural resource (biomass, geothermal, solar, and wind) overlaid with the national transmission grid and the major electricity load centers. The other set of maps shows the current installed capacity (biomass, geothermal, concentrating solar power, and wind), as well as a bar chart indicating the historic trend of generating capacity for the state. The book is organized into 13 chapters: • 1 - Introduction • 2 - Technology Profiles • 3 - Electricity Restructuring • 4 - Forecasts/Comparisons • 5 - Electricity Supply • 6 - Electricity Capability • 7 - Electricity Generation • 8 - Electricity Demand • 9 - Prices • 10 - Economic Indicators • 11 - Environmental Indicators • 12 - Conversion Factors • 13 - Geographic Information System (GIS) Maps This fourth edition of the Power Technologies Energy Data Book, as well as previous editions, are available on the Internet at http://www.nrel.gov/analysis/power_databook/. The PTEDB may be downloaded as a single PDF file, individual chapters, or table PDF files. Selected data also is available as Excel spreadsheets. The Web site also features energy-conversion calculators and features links to the Transportation Energy Data Book and Buildings Energy Data Book. [copied from http://www.nrel.gov/analysis/power_databook/chapter1.html

Aabakken, J°rn [Editor

195

Reactive Power from Distributed Energy  

SciTech Connect

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

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

2006-12-15

196

Photovoltaic energy in power market  

Microsoft Academic Search

Photovoltaic (PV) penetration in the grid connected power system has been growing. Currently, PV electricity is usually directly sold back to the energy supplier at a fixed price nd subsidy. However, subsidies should always be a temporary policy, and will eventually be terminated. A question is raised whether grid-connected PV generation will be more beneficial by making biddings in power

D. T. Ho; J. Frunt; J. M. A. Myrzik

2009-01-01

197

Energy discharge heater power supply  

SciTech Connect

The heater power supply is intended to supply capacitively stored,energy to embedded heater strips in cryo magnets. The amount of energy can be controlled by setting different charge different capacitor values. Two chassis' can be operated in series or interlocks are provided. The charge voltage, number of capacitors pulse can be monitored. There and dual channel has two discharge supplies in one chassis. This report reviews the characteristics of this power supply further.

Jaskierny, W.

1992-11-01

198

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

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

199

Metamaterial-inspired structures and concepts for elastoacoustic wave energy harvesting  

NASA Astrophysics Data System (ADS)

Enhancement of structure-borne wave energy harvesting is investigated by exploiting metamaterial-based and metamaterial-inspired electroelastic systems. The concepts of wave focusing, localization, and funneling are leveraged to establish novel metamaterial energy harvester (MEH) configurations. The MEH systems transform the incoming structure-borne wave energy into electrical energy by coupling the metamaterial and electroelastic domains. The energy harvesting component of the work employs piezoelectric transduction due to the high power density and ease of application offered by piezoelectric materials. Therefore, in all MEH configurations studied in this work, the metamaterial system is combined with piezoelectric energy harvesting for enhanced electricity generation from waves propagating in elastic structures. Experiments are conducted to validate the dramatic performance enhancement in MEH systems as compared to using the same volume of piezoelectric patch in the absence of the metamaterial component. It is shown that MEH systems can be used for both broadband and tuned wave energy harvesting. The MEH concepts covered in this paper are (1) wave focusing using a metamaterial-inspired parabolic acoustic mirror (for broadband energy harvesting), (2) energy localization using an imperfection in a 2D lattice structure (for tuned energy harvesting), and (3) wave guiding using an acoustic funnel (for narrow-to-broadband energy harvesting). It is shown that MEH systems can boost the harvested power by more than an order of magnitude.

Carrara, M.; Cacan, M. R.; Toussaint, J.; Leamy, M. J.; Ruzzene, M.; Erturk, A.

2013-06-01

200

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

201

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

202

Wave energy transmission apparatus for high-temperature environments  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

203

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

Microsoft Academic Search

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

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

2008-01-01

204

Power independent ignition energy measurements  

SciTech Connect

A portion of the electrical energy supplied to hot-wire ignitable materials is dissipated, largely through thermal conduction, to the unignited portion of the charge and to the containment and igniter system. The remainder of the energy deposited by the igniter wire raises the mass of material required for sustained reaction to the critical reaction temperature. The amount of energy dissipated is a direct function of the time from first application of power, to ignition. Time to ignition can be controlled by altering firing pulse power. Integration of the power pulse from start until ignition yields the ignition energy. Repetition of this procedure at different power levels permits one to plot energy versus firing time. Since conduction losses are time dependent, extrapolation of the resulting curve to zero time yields an ignition energy value that is independent of losses due to thermal conduction. A key to the success of the procedure is accurate observation of ignition time. It was found that the reaction energy released at ignition causes a discernible deflection in the firing current record. By comparison of light emission and current traces, it was found that the onset of deflagration occurs at the inflection point of the current trace deflection. This procedure has been successfully applied to hot pressed thermite samples, yielding ignition energies that are in qualitative agreement with the expected sensitivities of the samples.

Mohler, J.

1980-01-01

205

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

206

Dependence on axial magnetic field of radiation from a high-power gas-filled backward wave oscillator  

Microsoft Academic Search

Microwave output power from a high-power helium-filled backward wave oscillator (BWO) operating at X band is measured as a function of the strength of guiding magnetic field B and helium gas pressure. Tenuous helium gas filling the slow wave structure is ionized by an injected electron beam with typical parameters of energy 100 keV and current 0.5 kA. The enhancement

Kazuo Minami; Satoshi Kobayashi; Yutaka Hayatsu; Tsukasa Sato; Victor L. Granatstein

2002-01-01

207

Electric power generation: Tidal and wave power. (Latest citations from the Aerospace database). Published Search  

SciTech Connect

The bibliography contains citations concerning the feasibility of obtaining electric power from ocean disturbances such as waves, swells, and tides. The engineering and economic aspects are emphasized. Theoretical analysis of the power plant potential of selected sites around the world is included. (Contains 250 citations and includes a subject term index and title list.)

Not Available

1994-12-01

208

Fast wave power flow along SOL field lines in NSTX  

NASA Astrophysics Data System (ADS)

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

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

2012-10-01

209

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

PubMed

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

Gerasik, Vladimir; Stastna, Marek

2011-05-01

210

Efficient operation of a high-power {ital X}-band traveling wave tube amplifier  

SciTech Connect

We report experimental results demonstrating 54{percent} power conversion efficiency (43{percent} energy conversion efficiency), from a two-stage {ital X}-band traveling wave tube amplifier designed for high-power operation. The first stage of the amplifier is a 12-cm-long Boron Nitride dielectric section used to modulate the electron beam. The second stage consists of a long high-phase-velocity bunching section followed by a short low-phase-velocity output section. Output powers of up to 78 MW with narrow spectrum width were obtained with {approximately}700 kV, {approximately}200 A beam. {copyright} {ital 1999 American Institute of Physics.}

Wang, P.; Xu, Z.; Ivers, J.D.; Nation, J.A.; Naqvi, S.; Schachter, L. [Cornell University, Ithaca, New York 14853 (United States)] [Cornell University, Ithaca, New York 14853 (United States)

1999-10-01

211

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

SciTech Connect

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

Not Available

1983-09-01

212

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

Microsoft Academic Search

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

Marvin A. Geller; Jie Gong

2010-01-01

213

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

214

Constrained package millimeter-wave quasi-optical power combining amplifiers  

NASA Astrophysics Data System (ADS)

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 available from many solid state devices. Since the guided wave losses increase significantly in the mm-wave region, the use of power distributing circuits based on Wilkinson power dividers or four port hybrids is limited to combining the power from small number of devices. The output power from arbitrary number of devices can be combined if the power is added in free space, thus eliminating the guided wave losses. This has led to an increased interest in the quasi-optical power combining techniques in the recent years. This work describes a new quasi-optical power combining amplifier architecture and demonstrates its usefulness for practical mm-wave system applications. Several amplifying arrays have been fabricated and tested in order to verify the validity of this approach. Efficient power combining with amplifier gains of about 10.0 dB at 10 GHz is achieved. Feeding the amplifier array using electromagnetically hard horns 'constrained package' eliminates the spill over losses typical for other quasi- optical approaches and significantly reduces the system length. These horns act as power dividers and they are studied for the first time in such applications. In this work a mixed analytical/numerical algorithm is proposed to find the aperture fields of the horns. The predicted fields are compared with measurements of hard horns in X and Ka bands. Since, it is desirable to have the option of cascading several quasi-optical power combining amplifiers a special attention is given to the investigation of through-wafer and wafer-to-wafer transitions. The former is used to couple energy from the input side of the active layer to the output side through a ground plane while the latter couple energy from one active layer to next through an air gap. Insertion loss of less than 0.5 dB was achieved for both types of transitions.

Ivanov, Toni Georgiev

1997-12-01

215

Efficiency enhancement in high power backward-wave oscillators  

SciTech Connect

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

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

1999-06-01

216

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

217

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

NASA Astrophysics Data System (ADS)

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 TM021 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 ~910 kV and its current to be ~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.

2012-10-01

218

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

219

Directed Energy Applications for High Power Vacuum Electronics  

Microsoft Academic Search

Vacuum electronics are an important enabling technology for directed energy weapons. The technologies developed by the vacuum electronics community have played in important role in the development of both high power microwave and millimeter-wave systems. Modeling and simulation, leading to virtual prototyping of sources, is now central to the development of vacuum electronics-based DEWs. The future of HPM and mm-wave

K. E. Hackett

2006-01-01

220

Waves  

NSDL National Science Digital Library

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

Hansen, Mr.

2010-11-12

221

Sorting and Parameterization of Observed Saturn and Jupiter Chorus Wave Power  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

222

High power, Ultra-Long-Pulsed gyrotron backward wave oscillators  

Microsoft Academic Search

The objective of this research program was to explore tapering of interaction tubes and magnetic fields as techniques for enhancing the performance of high power microwave gyrotron-backward-wave- oscillators (gyro-BWOs). Experiments were performed on the Michigan Electron Long-Beam Accelerator, (MELBA), which operated with parameters: voltage = 0.7-0.9 MV, diode current = 1-10 kA, injected current = 1-4 kA, and pulselengths of

Ronald M. Gilgenbach

1995-01-01

223

Water Power for a Clean Energy Future (Fact Sheet)  

SciTech Connect

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

Not Available

2012-03-01

224

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

225

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

226

Relativistic waves raised by explosions in space as sources of ultra-high-energy cosmic rays  

NASA Astrophysics Data System (ADS)

The paper discusses the possibility of particle acceleration up to high energies in relativistic waves generated by various explosive processes in the interstellar medium. We propose to use the surfatron mechanism of acceleration (surfing) of charged particles trapped in the front of relativistic waves as a generator of high-energy cosmic rays (CRs). Conditions under which surfing in the waves under consideration can be made are studied thoroughly. Ultra-high-energy CRs (up to 1020 eV) are shown to be obtained due to the surfing in relativistic plane and spherical waves. Surfing is supposed to take place in nonlinear Langmuir waves excited by powerful electromagnetic radiation or relativistic beams of charged particles, as well as in strong shock waves generated by relativistic jets or spherical formations that expand fast (fireballs).

Kichigin, G. N.

2013-01-01

227

High-power microwave source based on an unmagnetized backward-wave oscillator  

Microsoft Academic Search

A unique, high-power microwave source, called PASOTRON (Plasma-Assisted Slow-wave Oscillator), has been developed. The PASOTRON utilizes a long-pulse E-gun and plasma-filled slow-wave structure (SWS) to produce high-energy microwave pulses from a simple, lightweight device that utilizes no externally-produced magnetic fields. The novel E-gun employs a low-pressure glow discharge to provide a stable, high current-density electron source. A high-perveance, multi-aperture electron

D. M. Goebel; J. M. Butler; R. W. Schumacher; J. Santoru; R. L. Eisenhart

1994-01-01

228

Power and energy for posterity  

NASA Technical Reports Server (NTRS)

The use of sophisticated space energy generation and storage systems to benefit the general public was examined. The utilization of these systems for pollution-free generation of energy to satisfy mankind's future electrical, thermal, and propulsion needs was of primary concern. Ground, air, and space transportation; commercial, peaking, and emergency electrical power; and metropolitan and unit thermal energy requirements were considered. Each type of energy system was first analyzed in terms of its utility in satisfying the requirement, and then its potential in reducing the air, noise, thermal, water, and nuclear pollution from future electrical and thermal systems was determined.

Barthelemy, R. F.; Cooper, R. F.

1972-01-01

229

Millimeter wave power density in aqueous biological samples.  

PubMed

Power density distribution inside a water sample placed between two parallel lossy dielectric plates (Polystyrene) was calculated using Fresnel equations for the frequency range of 42.25-53.57 GHz. Due to the multiple internal reflections from the sample boundaries, the distribution of the power density within the thin sample is more uniform than that within a semi-infinite medium. The power density in a sample depends on the thicknesses of the sample and the adjacent dielectric plates. For the given frequency range the sample thickness optimal for power density uniformity varies between 0.28 and 0.33 mm. The front plate has a significant effect on the magnitude of the power density within the sample but little effect on the power density distribution. The thicker the rear plate, the greater is the non uniformity of the power density distribution within the sample. Based on the calculated data, we determined the dimension of an exposure chamber providing the optimal power density distribution uniformity for mm-wave irradiation. PMID:11298391

Alekseev, S I; Ziskin, M C

2001-05-01

230

Deep ocean wave energy conversion using a cycloidal turbine  

Microsoft Academic Search

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

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

2011-01-01

231

Ocean Wave Energy Regimes of the Circumpolar Coastal Zones  

Microsoft Academic Search

Ocean wave activity is a major enviromental forcing agent of the ice-rich sediments that comprise large sections of the arctic coastal margins. While it is instructive to possess information about the wind regimes in these regions, direct application to geomorphological and engineering needs requires knowledge of the resultant wave-energy regimes. Wave energy information has been calculated at the regional scale

D. E. Atkinson

2004-01-01

232

Estimating Internal Wave Energy Fluxes in the Ocean  

Microsoft Academic Search

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

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

2005-01-01

233

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

NASA Astrophysics Data System (ADS)

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

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

1996-11-01

234

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

235

Joining of ceramic tubes using a high-power 83GHz millimeter-wave beam  

Microsoft Academic Search

Summary form only given. The high power beams that can be generated by CW gyrotrons represent a promising energy source for high-temperature processing of materials. An experimental facility based on an 83-GHz, 15 kW CW industrial gyrotron has been set up at the Naval Research Laboratory to investigate novel mm-wave-beam-based approaches to processing ceramic materials including sintering, coating, and joining

R. W. Bruce; R. L. Bruce; S. H. Gold; M. Kahn; A. K. Kinkead; A. W. Fliflet; M. A. Imam

2004-01-01

236

Heating of ceramic joints by a high-power 83GHz millimeter-wave beam  

Microsoft Academic Search

Summary form only given, as follows. The high power beams which can be generated by CW gyrotrons represent a promising new energy source for high-temperature processing of materials. An experimental facility based on an 83-GHz, 15-kW CW industrial gyrotron, produced by Gycom Ltd., has been set up at the Naval Research Laboratory to investigate novel mm-wave-beam-based approaches to processing ceramic

A. W. Fliflet; S. H. Gold; M. Kahn; R. W. Bruce; A. K. Kinkead; R. P. Fischer; M. A. Imam

2002-01-01

237

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

238

Demand, Energy, and Power Factor.  

National Technical Information Service (NTIS)

This paper briefly presents the results of a study of various utility rate schedules from across the United States and describes a video produced to explain some major features of these rate structures. In particular, the demand, energy and power factor s...

M. J. Gough

1994-01-01

239

Ocean wave energy conversion using piezoelectric material members  

Microsoft Academic Search

This patent describes an apparatus for converting mechanical energy from surface waves on a body of water to electrical energy comprising a float for up and down movement in response to the waves, a prezoelectric member for converting strains thereof to electrical energy, and energy transfer means for coupling the up and down movement of the float to the member

1987-01-01

240

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

241

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

Microsoft Academic Search

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

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

2003-01-01

242

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

Microsoft Academic Search

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

Jahangir Khan; Ali Moshref; Gouri Bhuyan

2009-01-01

243

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

NASA Technical Reports Server (NTRS)

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

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

2007-01-01

244

A low-cost float method of harnessing wave energy  

SciTech Connect

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

George, M.P.

1983-12-01

245

Laser power stabilization for second-generation gravitational wave detectors.  

PubMed

We present results on the power stabilization of a Nd:YAG laser in the frequency band from 1 Hz to 100 kHz. High-power, low-noise photodetectors are used in a dc-coupled control loop to achieve relative power fluctuations down to 5 x 10(-9) Hz(-1/2) at 10 Hz and 3.5 x 10(-9) Hz(-1/2) up to several kHz, which is very close to the shot-noise limit for 80 mA of detected photocurrent on each detector. We investigated and eliminated several noise sources such as ground loops and beam pointing. The achieved stability level is close to the requirements for the Advanced LIGO gravitational wave detector. PMID:16770412

Seifert, Frank; Kwee, Patrick; Heurs, Michèle; Willke, Benno; Danzmann, Karsten

2006-07-01

246

Hydro, tidal and wave energy in Australia  

Microsoft Academic Search

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

David Harries; Mark McHenry; Philip Jennings; Chacko Thomas

2006-01-01

247

Radiant energy power source structure  

SciTech Connect

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 casing. It comprises: a modified elongated annular combustion casing; a plurality of pairs of circumferentially spaced apart ribs operably attached to the elongated annular base; at least one photovoltaic cell operably situated between each pair of longitudinal ribs; a set of opposed, longitudinally extending grooves formed in the pair of ribs at a location radially spaced from the at least one photovoltaic cell; and a protective plate removable carried in the grooves.

Doellner, O.L.

1992-07-14

248

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

NASA Astrophysics Data System (ADS)

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

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

2014-06-01

249

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

250

High power continuous wave injection-locked solid state laser  

SciTech Connect

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

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

1991-06-25

251

Energy harvesting from a standing wave thermoacoustic-piezoelectric resonator  

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

252

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

PubMed

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

Declercq, Nico Felicien

2014-02-01

253

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

PubMed

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. PMID:23214660

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

2012-10-01

254

ELMy H-mode confinement and threshold power by low hybrid wave on the EAST tokamak  

NASA Astrophysics Data System (ADS)

Stationary type-III ELMy H-mode plasmas were achieved on Experimental Advanced Superconducting Tokamak (EAST) by low hybrid wave in 2010. The threshold power increases with plasma density, and a significant reduction in the H-mode occurs by decreasing the distance between the X-point and the strike point at the outside lower divertor on EAST. A series of statistics for the H-mode confinement such as the dependence of energy confinement time (?E) on plasma density and loss power is experimentally studied in detail.

Liu, Z. X.; Gao, X.; Zhang, W. Y.; Li, J. G.; Gong, X. Z.; Jie, Y. X.; Zhang, S. B.; Zeng, L.; Shi, N.; the EAST Team

2012-08-01

255

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

256

Experimental determination of radiated internal wave power without pressure field data  

NASA Astrophysics Data System (ADS)

We present a method to determine, using only velocity field data, the time-averaged energy flux <{J}> and total radiated power P for two-dimensional internal gravity waves. Both <{J}> and P are determined from expressions involving only a scalar function, the stream function ?. We test the method using data from a direct numerical simulation for tidal flow of a stratified fluid past a knife edge. The results for the radiated internal wave power given by the stream function method agree to within 0.5% with results obtained using pressure and velocity data from the numerical simulation. The results for the radiated power computed from the stream function agree well with power computed from the velocity and pressure if the starting point for the stream function computation is on a solid boundary, but if a boundary point is not available, care must be taken to choose an appropriate starting point. We also test the stream function method by applying it to laboratory data for tidal flow past a knife edge, and the results are found to agree with the direct numerical simulation. The supplementary material includes a Matlab code with a graphical user interface that can be used to compute the energy flux and power from two-dimensional velocity field data.

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

2014-04-01

257

Control strategies to optimise power output in heave buoy energy convertors  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

258

Scattered surface wave energy in the seismic coda  

USGS Publications Warehouse

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

Zeng, Y.

2006-01-01

259

Speech articulator measurements using low power EM-wave sensors  

SciTech Connect

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

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

1998-01-01

260

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

261

The energy injection into waves with a zero group velocity  

Microsoft Academic Search

The frequency maxima of electron cyclotron harmonic (ECH) waves provide strong responses to sounding in various plasma regimes in the solar system. The frequency maxima correspond to waves for which the group velocity and thus the energy propagation velocity in the plasma frame of reference is zero. A particle-in-cell (PIC) code is employed to show that the propagation of wave

M. E. Dieckmann; S. C. Chapman; A. Ynnerman; G. Rowlands

1999-01-01

262

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

Microsoft Academic Search

The quantitative similarity of temperature fluctuations in the jovian and terrestrial middle atmospheres strengthens the case for breaking gravity waves in Jupiter's middle atmosphere.1 Breaking gravity waves directly contribute to both heating (by local deposition of wave energy) and cooling (by turbulent mixing of potential temperature). The net effect2 depends on eddy diffusion and the eddy Prandtl number, Pr, the

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

2003-01-01

263

Submerged cylinder wave energy device - Theory and experiment  

Microsoft Academic Search

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

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

1979-01-01

264

Wave Turbulence in Superfluid 4He: Energy Cascades & Rogue Waves in the Laboratory  

Microsoft Academic Search

Recent work on second sound acoustic turbulence in superfluid 4He 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

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

2008-01-01

265

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

Microsoft Academic Search

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

A. Babarit; A. H. Clément

2006-01-01

266

The Physics Classroom: Work, Energy, and Power  

NSDL National Science Digital Library

This chapter of The Physics Classroom tutorial ties together the concepts of work, power, and the Law of Conservation of Energy. Six interactive tutorials explore kinetic and potential energy, power, mechanical energy, and the relationship between energy and forces. It also gives students practice in calculating work and using energy bar charts. f

Henderson, Tom

2005-03-16

267

Ocean wave energy conversion: inexpensive energy source yields significant results through simple methods  

Microsoft Academic Search

Pneumatic ocean wave energy conversion has been in existence since the early twentieth century. In pneumatic wave energy conversion, internal water motions are excited by the external water wave. Depending on the volume of water in the capture chamber, resonance with the external wave may occur. That is, the natural frequency of the rising and falling internal water column may

1986-01-01

268

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

USGS Publications Warehouse

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

Adams, P.; Ruggiero, P.

2006-01-01

269

Tidal energy in electric power systems  

Microsoft Academic Search

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

S. Sheth; M. Shahidehpour

2005-01-01

270

Solid state power modulator for terrestrial and spaceborne short pulse millimeter wave radar transmitters  

Microsoft Academic Search

A new generation of power modulators has been developed especially for use in millimeter wave radar applications. The development was focused on a design suitable for a reliable long life operation in a rugged environment or in space. The design requirements for the power modulator are dedicated to a millimeter wave extended interaction klystron with an RF output power of

M. Gollor; W. Muller

2000-01-01

271

Loss of energy of internal solitary wave over underwater obstacle  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

272

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

273

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

274

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

275

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

276

Fundamentals of ocean wave energy conversion, modeling, and control  

Microsoft Academic Search

A collection of slides covering the fundamentals of ocean wave energy conversion, modeling and control was presented. The author first discussed the wave energy and resources fundamentals. A simple modelling and control assuming frequency independent hydrodynamic parameters and linearity was presented.

T. Brekken

2010-01-01

277

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 more conventional generator types, the three-phase permanent-magnet synchronous generator with iron in both stator and translator is most suitable, because it is

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

2003-01-01

278

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

279

Careers in Geothermal Energy: Power from below  

ERIC Educational Resources Information Center

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

Liming, Drew

2013-01-01

280

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

281

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

PubMed

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

Kural, A; Pullin, R; Holford, K; Lees, J; Naylon, J; Paget, C; Featherston, C

2013-06-01

282

a Study of Capillary and Capillary-Gravity Wind Waves: Their Structures, Distributions, and Energy Balances  

NASA Astrophysics Data System (ADS)

Wave forms, two dimensional structures, and wavenumber spectra of very short wind waves are studied in a laboratory wind wave tank with an optical detector. In this technique the water surface elevation gradient is encoded by colors so that a camera can record the surface gradient information in two dimensions. As a consequence the shape of the water surface can be reconstructed and wave forms and structures can be examined extensively. Short waves in the capillary range featuring sharp troughs and flat crests are very commonly seen among wind waves though very steep gravity waves are rarely found. Our observations show that most short waves do not have very large slopes. Wave forms that resemble capillary-gravity solitons are observed with a close match to the form theoretically predicted for potential flow. Capillaries are mainly to be found as parasitic capillaries on the forward faces of gravity waves. The longest wavelengths of parasitic capillaries found are less than 1 cm. An important feature of the short wave energy distribution is that widening of the angular spread of spectra is not monotonic with increasing wavenumber. There is a local minimum of angular spreading in the spectral band of parasitic capillaries. There is a characteristic dip at the gravity-capillary transition wavenumber of the energy spectra integrated over all directions and this dip becomes filled in as the wind increases. The spectral cutoff at high wavenumbers shows a power law behavior with an exponent of about minus four. The wavenumber range between transition to cutoff does not vary rapidly with change of wind speed. A model of the energy balance of short waves is schematically developed to explain some characteristic features of the spectrum. Viscous damping, long wave straining, and several orders of wave-wave interactions are taken into account. The minus fourth power law cutoff in the capillary range can be explained in this way. The concept of an equilibrium spectrum remains useful. According to the model the dip in the spectrum at the capillary-gravity transition is a result of blockage of both capillary-gravity wind waves and parasitic capillaries.

Zhang, Xin

1992-01-01

283

Wave spectral energy variability in the northeast Pacific  

USGS Publications Warehouse

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

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

2005-01-01

284

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

NASA Astrophysics Data System (ADS)

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

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

2013-10-01

285

Alternative Energy and Remote Power Products  

NSDL National Science Digital Library

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

2008-09-30

286

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

Microsoft Academic Search

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

Frank Hegeler; Chris Grabowski; Edl Schamiloglu

1998-01-01

287

Wave scattering approach to power flow in frame structures and piping networks  

Microsoft Academic Search

A general matrix method is presented for the analysis of power flow in two- and three-dimensional frames using a wave scattering approach. Axial, torsional, and flexural wave modes are included. Since the method is intended to be used for mid and high frequency analysis, shear deformation and rotary inertia are included in the flexural wave modes. A general formulation is

Linda Sue Beale

2000-01-01

288

High-power millimeter-wave Gyro-Amplifiers: technological advances and applications  

Microsoft Academic Search

Summary form only given. Fastwave devices, and in particular, gyro-devices are capable in principle ofproducing quantities ofpower in the millimeter wave bands which far exceeds that producible by conventional slow wave linear-beam devices. Gyrotron oscillators have been in development for decades as efficient sources of high power millimeter waves for such applications as the electron cyclotron heating of fusion plasmas

B. G. Danly

2000-01-01

289

Parametric Energy Coupled Uninterruptible Power Supply.  

National Technical Information Service (NTIS)

A parametric energy coupling system is described for providing uninterruptible a-c power to electrical loads. In a normal mode, a parametric transformer couples a-c line power directly from an a-c power source to a load. Upon a power outage occurrence, an...

D. M. Hannemann D. M. Shiroma K. T. Huang

1977-01-01

290

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

Microsoft Academic Search

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

S. S. Y. Narayanan; S. Bose

1996-01-01

291

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

292

Active Power and Nonactive Power Control of Distributed Energy Resources  

SciTech Connect

Distributed energy resources (DE) have been widely used in the power systems to supply active power, and most of the present DE resources are operated with limited or without nonactive power capability. This paper shows that with a slight modification in hardware configuration and a small boost in the power ratings, as well as proper implementation of control strategies, a DE system with a power electronics converter interface can provide active power and nonactive power simultaneously and independently. A DE can provide dynamic voltage regulation to the local bus because of its nonactive power capability. Furthermore, the proposed DE control method in this paper can effectively compensate the unbalance in the local voltage. The system requirements such as the inverter current rating and the dc voltage rating are discussed. The analysis of the system requirements to provide nonactive power shows that it is cost-effective to have DE provide voltage regulation.

Xu, Yan [ORNL; Li, Fangxing [ORNL; Rizy, D Tom [ORNL; Kueck, John D [ORNL

2008-01-01

293

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

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

294

High-power traveling wave tubes powered by a relativistic electron beam  

SciTech Connect

This thesis presents the results of a high power traveling wave tube a high power, rippled wall waveguide TWT powered by a relativistic electron beam. Initially, the amplifiers consisted of a single section of slow wave structure. Two TWT's of this type were used, with lengths of 11 and 22 periods. These single state tubes were linear and operated in the Tm{sub 01} mode at maximum gains of 33 dB and bandwidths on order of 20 MHz centered at 8.76 GHz. The maximum efficiency was 11% corresponding to an output power of 110 MW. Below beam currents of 1.4 kA, the single stage tubes were monochromatic and phase stable to within {plus minus}8{degree}; however, above this current, a sideband-like structure developed in the frequency spectrum. The two sidebands were unequally displaced from the center frequency. As the current was increased still further to 1.6 kA, the single stage amplifier oscillated due to positive feedback arising from reflections at the exit taper of the TWT. At this point, the TWT was no longer useful as an amplifier. To reduce the positive feedback and stop the oscillations, the author severed the amplifier. Two different lengths of sever were used, the shorter of the two having the highest gain. The shorter sever saturated at 975 A, with a total gain of 37 dB and total power output of 410 MW. Beyond this current, the tube was no longer linear with respect to the input power. The bandwidth of severed tube was about 100 MHz centered at 8.76 GHz. The severed amplifiers showed the sideband-like behavior at all the beam currents used. The sideband frequency separation from the center frequency increased with beam current.

Shiffler, D.A. Jr.

1991-01-01

295

Open cycle traveling wave thermoacoustics: Energy fluxes and thermodynamics  

Microsoft Academic Search

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

Nathan T. Weiland; Ben T. Zinn

2004-01-01

296

Ultrasonic Power Measurement by the Radiation Force Balance Method —Experimental Results using Burst Waves and Continuous Waves  

NASA Astrophysics Data System (ADS)

Results of ultrasonic power measurements using a radiation force balance system constructed at National Institute of Advanced Industrial Science and Technology (AIST) are described. The aim of this research is to establish the ultrasonic power standard for medical ultrasonics. The experimental results of the linearity of the system under 1 mW to about 60 mW for the continuous and the burst waves are presented. It is also confirmed that the measured ultrasonic power is not affected by the repetition rate of the burst wave.

Kikuchi, Tsuneo; Sato, Sojun; Yoshioka, Masahiro

2002-05-01

297

ENERGY CONTENT AND PROPAGATION IN TRANSVERSE SOLAR ATMOSPHERIC WAVES  

SciTech Connect

Recently, a significant amount of transverse wave energy has been estimated propagating along solar atmospheric magnetic fields. However, these estimates have been made with the classic bulk Alfven wave model which assumes a homogeneous plasma. In this paper, the kinetic, magnetic, and total energy densities and the flux of energy are computed for transverse MHD waves in one-dimensional cylindrical flux tube models with a piecewise constant or continuous radial density profile. There are fundamental deviations from the properties for classic bulk Alfven waves. (1) There is no local equipartition between kinetic and magnetic energy. (2) The flux of energy and the velocity of energy transfer have, in addition to a component parallel to the magnetic field, components in the planes normal to the magnetic field. (3) The energy densities and the flux of energy vary spatially, contrary to the case of classic bulk Alfven waves. This last property has the important consequence that the energy flux computed with the well known expression for bulk Alfven waves could overestimate the real flux by a factor in the range 10-50, depending on the flux tube equilibrium properties.

Goossens, M.; Van Doorsselaere, T. [Centre for mathematical Plasma Astrophysics, Mathematics Department, Celestijnenlaan 200B bus 2400, B-3001 Heverlee (Belgium); Soler, R. [Solar Physics Group, Departament de Fisica, Universitat de les Illes Balears, E-07122 Palma de Mallorca (Spain); Verth, G., E-mail: tom.vandoorsselaere@wis.kuleuven.be [Solar Physics and Space Plasma Research Centre (SP2RC), School of Mathematics and Statistics, University of Sheffield, Hounsfield Road, Hicks Building, Sheffield S3 7RH (United Kingdom)

2013-05-10

298

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

NASA Technical Reports Server (NTRS)

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

Musielak, Zdzislaw E.

1986-01-01

299

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

300

Power Systems Faults Location with Traveling Wave Based on Hilbert-Huang Transform  

Microsoft Academic Search

Identification of the signal of traveling wave is the key for power line faults location. Hilbert-Huang Transform (HHT), as a kind of time-frequency analysis method, is proposed to analysis the signal in the power system. Traveling wave of the fault circuitry is decomposed by the empirical mode decomposition (EMD), and the inherent mode functions (IMF) are extracted. Then Hilbert transform

Zhang Liguo; Han Xu; Jia Jian; Gao Tianye; Ma Yongsheng

2009-01-01

301

Strong Scattering of High Power Millimeter Waves in Tokamak Plasmas with Tearing Modes  

Microsoft Academic Search

In tokamak plasmas with a tearing mode, strong scattering of high power millimeter waves, as used for heating and noninductive current drive, is shown to occur. This new wave scattering phenomenon is shown to be related to the passage of the O point of a magnetic island through the high power heating beam. The density determines the detailed phasing of

E. Westerhof; M. R. De Baar; W. A. Bongers; B. A. Hennen; D. J. Thoen; S. K. Nielsen; M. Salewski; S. B. Korsholm; F. Leipold; D. Moseev; M. Stejner; J. W. Oosterbeek; A. Buerger

2009-01-01

302

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

NASA Astrophysics Data System (ADS)

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

Lin, Bin; Giurgiutiu, Victor

2010-03-01

303

A time domain energy theorem for scattering of plane electromagnetic waves  

NASA Astrophysics Data System (ADS)

A time domain energy theorem for the scattering of plane electromagnetic waves by an obstacle of bounded extent is derived. It is the counterpart in the time domain of the "optical theorem" or the "extinction cross section theorem" in the frequency domain. No assumptions as to the electromagnetic behavior of the obstacle need to be made; so, the obstacle may be electromagnetically nonlinear and/or time variant (a kind of behavior that is excluded in the frequency domain result). As to the wave motion, three different kinds of time behavior are distinguished: (1) transient, (2) periodic, and (3) perpetuating, but with finite mean power flow density. For all three cases the total energy (case 1) or the time-averaged power (cases 2 and 3) that is both absorbed and scattered by the obstacle is related to a certain time interaction integral of the incident plane wave and the spherical-wave amplitude of the scattered wave in the far-field region, when observed in the direction of propagation of the incident wave. The practical implications of the energy theorem are briefly indicated.

Hoop, A. T.

1984-09-01

304

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

305

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

306

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

307

Power marketing and renewable energy  

SciTech Connect

Power marketing refers to wholesale and retail transactions of electric power made by companies other than public power entities and the regulated utilities that own the generation and distribution lines. The growth in power marketing has been a major development in the electric power industry during the last few years, and power marketers are expected to realize even more market opportunities as electric industry deregulation proceeds from wholesale competition to retail competition. This Topical Issues Brief examines the nature of the power marketing business and its relationship with renewable power. The information presented is based on interviews conducted with nine power marketing companies, which accounted for almost 54% of total power sales by power marketers in 1995. These interviews provided information on various viewpoints of power marketers, their experience with renewables, and their respective outlooks for including renewables in their resource portfolios. Some basic differences exist between wholesale and retail competition that should be recognized when discussing power marketing and renewable power. At the wholesale level, the majority of power marketers stress the commodity nature of electricity. The primary criteria for developing resource portfolios are the same as those of their wholesale customers: the cost and reliability of power supplies. At the retail level, electricity may be viewed as a product that includes value-added characteristics or services determined by customer preferences.

Fang, J.M.

1997-09-01

308

An energy budget for waves and turbulence within an inversion  

Microsoft Academic Search

Several features of the maintenance of breaking gravity waves and turbulence in a marine inversion are examined. A formulation is proposed for a critical Richardson number based on a mutual response of the mean and turbulent states to a wave-like disturbance. The energy balance, based on averaged aircraft soundings, is examined to ascertain the order of magnitude of the component

Bryan R. Kerman

1974-01-01

309

Energy Cascading in the Beat-Wave Accelerator.  

National Technical Information Service (NTIS)

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, i...

C. J. McKinstrie S. H. Batha

1987-01-01

310

Power quality improvement and uninterruptible power supply using a power conditioning system with energy storage capability  

Microsoft Academic Search

A power conditioning system with energy storage capability is proposed as a viable solution for improving the quality and the reliability of the electric energy supply. Several tasks can be performed at the same time, such as reactive power compensation, current harmonic reduction, and smoothing of pulsating loads. Moreover, the power conditioning system can operate as an uninterruptible power supply

D. Casadei; G. Grandi; G. Serra; C. Rossi

2005-01-01

311

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

Microsoft Academic Search

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.

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

2011-01-01

312

High-power millimeter-wave transmitter for the NRL WARLOC radar  

Microsoft Academic Search

High power millimeter wave instrumentation radars have a number of important applications ranging from defense missions to basic scientific studies At the Naval Research Laboratory, a new high power 94 GHz radar named WARLOC has been developed. This radar employs a high power gyro-klystron as the final power amplifier and was developed during 1996-2001. The WARLOC radar has been integrated

M. T. Ngo; B. G. Danly; R. Myers; D. E. Pershing; V. Gregers-Hansen; G. Linde

2002-01-01

313

Power Measurement Methods for Energy Efficient Applications  

PubMed Central

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

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

2013-01-01

314

The role of drift mass in the kinetic energy and momentum of periodic water waves and sound waves  

Microsoft Academic Search

For two-dimensional periodic water waves or sound waves, the kinetic energy per wavelength is 1\\/2 mdc2, and the momentum per wavelength is ±mdc, where c is the wave velocity, and md is the drift mass per wavelength. These results also hold for three-dimensional periodic waves, for which the kinetic energy, momentum, and drift mass are all for one wave cell,

Chia-Shun Yih

1997-01-01

315

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

NASA Astrophysics Data System (ADS)

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

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

2011-06-01

316

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

317

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

PubMed

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

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

2011-06-01

318

Application of BP artificial neural networks in modelling energy obtained by wave energy system  

Microsoft Academic Search

As one of the renewable energy, the absorption and utilization of wave energy is always an important research field home and abroad, and energy absorption efficiency is the key. A wave energy absorption system based on inertial pendulum is presented, and dynamics equations are established. Artificial Neural network with learning rate adaptation is adopted to model in time domain. The

Zhang Ying; Li Mengxin; Dong Zaili

2009-01-01

319

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

Microsoft Academic Search

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

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

2011-01-01

320

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

321

On energy potential of millimeter-wave radar  

Microsoft Academic Search

One of the most serious problems of a short-pulse millimeter (MM) wave radar is deficit of its energy potential. The radar range upper limit of about a few kilometers is caused mostly by two factors: (1) low energy of transmitting signal pulses restricted by generator overheating or breakdown of waveguiding structures; and (2) decreasing of signal energy received because of

B. A. Rozanov; G. V. Cheslavsky

1998-01-01

322

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

323

Mini-Scale Power Distribution Network Feeding Trapezoidal-Wave Voltages to Power Electronic Loads with Diode Rectifiers  

Microsoft Academic Search

This paper proposes a novel three-phase power distribution system feeding trapezoidal voltages to various power electronic loads with diode rectifier front-ends. The network distributes trapezoidal voltages generated by synchronous superposition of wave-shaping voltages onto sinusoidal voltages available from a utility power grid. The power distribution by the trapezoidal voltages allows reducing harmonics of the line currents without electronic switching devices

Toshihiko Noguchi; Masaru Imoto; Yoshikazu Sato

2004-01-01

324

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

325

Equilibrium shoreline response of a high wave energy beach  

USGS Publications Warehouse

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

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

2011-01-01

326

Equilibrium shoreline response of a high wave energy beach  

NASA Astrophysics Data System (ADS)

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

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

2011-04-01

327

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

328

Solar energy thermally powered electrical generating system  

NASA Technical Reports Server (NTRS)

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

Owens, William R. (Inventor)

1989-01-01

329

Measurement of laser energy and power  

Microsoft Academic Search

Measurements of laser energy and power are discussed with emphasis on those methods which attempt to establish the accuracy or standards for such measurements. Devices to attenuate laser radiation are summarized. The principles and limitations of the methods are stressed rather than design details of the apparatus. It is found that standards for the measurement of laser power and energy

GEORGE BIRNBAUM; MILTON BIRNBAUM

1967-01-01

330

Power electronics and alternative energy generation  

Microsoft Academic Search

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

James P Lyons; Vlatko Vlatkovic

2004-01-01

331

Electron Trapping in Shear Alfven Waves that Power the Aurora  

SciTech Connect

Results from 1D Vlasov drift-kinetic plasma simulations reveal how and where auroral electrons are accelerated along Earth's geomagnetic field. In the warm plasma sheet, electrons become trapped in shear Alfven waves, preventing immediate wave damping. As waves move to regions with larger v{sub Te}/v{sub A}, their parallel electric field decreases, and the trapped electrons escape their influence. The resulting electron distribution functions compare favorably with in situ observations, demonstrating for the first time a self-consistent link between Alfven waves and electrons that form aurora.

Watt, Clare E. J.; Rankin, Robert [University of Alberta, Edmonton, Alberta (Canada)

2009-01-30

332

75 FR 11169 - Reedsport OPT Wave Park Project; Reedsport OPT Wave Park; LLC Notice of Scoping Meetings and...  

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF ENERGY Federal Energy Regulatory Commission...12713-002] Reedsport OPT Wave Park Project; Reedsport...Secretary, Federal Energy Regulatory Commission...include 10 OPT PowerBuoy wave- powered generating...

2010-03-10

333

Power-amplifying strategy in vibration-powered energy harvesters  

Microsoft Academic Search

A new cantilevered piezoelectric energy harvester (PEH) of which the additional lumped mass is connected to a harmonically oscillating base through an elastic foundation is proposed for maximizing generated power and enlarging its frequency bandwidth. The base motion is assumed to provide a given acceleration level. Earlier, a similar energy harvester employing the concept of the dynamic vibration absorber was

Pyung Sik Ma; Jae Eun Kim; Yoon Young Kim

2010-01-01

334

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

335

Evaluation of an energy-propagation wave refraction model  

NASA Astrophysics Data System (ADS)

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

Vincent, C. E.; Carrie, A.

1988-03-01

336

Dam-Atoll for concentration and conversion of ocean wave energy  

Microsoft Academic Search

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

T. P. Higgins; C. P. Sherburne

1981-01-01

337

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

Microsoft Academic Search

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

Hans Bernhoff; Elisabeth Sjöstedt; Mats Leijon

2006-01-01

338

Energy Absorption Structure of Laser Supported Detonation Wave  

NASA Astrophysics Data System (ADS)

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 are important to be understood, which was still not clear though some visualized experiments have been conducted by Ushio et al. before. In this paper, 2-wavelength Mach-Zehnder interferometry is brought to investigate the electron density distribution of LSD area. At the same time, the temperature of the laser induced plasma is measured by an emission spectroscopy experiment, and calculated based on the assumption of local thermal equilibrium. The results show that in LSD, the electron density has a peak (as high as 2×1024[m-3]) behind the shock wave. The irradiated laser can be entirely absorbed before reaching the position of this peak. As a result, a new peak is always generating in front of the old one and this propagating has the same velocity as that of the blast wave. In this way, high heating ratio is sustained right after the shock front. However, as the laser pulse energy becomes lower, the propagating peak cannot catch up with the blast wave anymore, which leads to a termination of the LSD wave. From this study, it is found that for sustaining the LSD wave, a sufficiently thin laser absorption layer is necessary.

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

2010-05-01

339

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

340

An electrical approach to wave energy conversion  

Microsoft Academic Search

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

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

2006-01-01

341

High power, continuous-wave, quantum cascade lasers for MWIR and LWIR applications  

Microsoft Academic Search

Over the past several years, our group has endeavored to develop high power quantum cascade lasers for a variety of remote and high sensitivity infrared applications. The systematic optimization of laser performance has allowed for demonstration of high power, continuous-wave quantum cascade lasers operating above room temperature. Since 2002, the power levels for individual devices have jumped from 600 mW.

S. Slivken; A. Evans; J. S. Yu; S. R. Darvish; M. Razeghi

2006-01-01

342

Pulsed Power Driven Fusion Energy  

SciTech Connect

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

SLUTZ,STEPHEN A.

1999-11-22

343

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

Microsoft Academic Search

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

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

1995-01-01

344

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

Microsoft Academic Search

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

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

2009-01-01

345

Local energy decay for linear wave equations with variable coefficients  

NASA Astrophysics Data System (ADS)

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

Ikehata, Ryo

2005-06-01

346

Acoustic Intensity: Energy Transfer, Wave Properties, and Applications  

Microsoft Academic Search

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 energy transfer is described by the instantaneous intensity, which contains contributions by the active intensity and the reactive intensity. The time independent intensity vectors

Julian Adin Mann III

1988-01-01

347

Acoustic intensity: Energy transfer, wave properties and applications  

Microsoft Academic Search

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 energy transfer is described by the instantaneous intensity, which contains contributions by the active intensity and the reactive intensity. The time independent intensity vectors

Julian A. Mann III

1988-01-01

348

Nuclear power and energy planning.  

National Technical Information Service (NTIS)

With the rapid depletion of conventional energy sources such as coal and oil and the growing world demand for energy the question of how to provide the extra energy needed in the future is addressed. Relevant facts and figures are presented. Coal and oil ...

P. Jones

1990-01-01

349

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.

350

Laser energy converted into electric power  

NASA Technical Reports Server (NTRS)

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

Shimada, K.

1973-01-01

351

High Power Microwave Generation in a Backward Wave Oscillator with a Central Conductor  

Microsoft Academic Search

High power microwave radiation generated by Backward Wave Oscillators (BWOs) and Travelling Wave Tubes has been extensively studied for many years. Both of these devices use the interaction of an electron beam (typically an annular beam) with a rippled waveguide to generate microwaves. In this paper, the effects of placing a central conducting rod inside the annulus of the annular

Douglas Young

2001-01-01

352

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

353

Analysis of a novel brazed helix tape slow wave structure with high power capability  

Microsoft Academic Search

Summary form only given. In order to enhance the power capability of the helix traveling wave tube, a novel helical slow wave structure (SWS) supported by 8 wedge shaped discontinuous dielectric pillars which exist only at the helix tape in each pitch, is developed in this paper. Each pillar can be easily brazed with the helix tape and the metal

Yubin Gong; Yanyu Wei; Wenxiang Wang; Zhaoyun Duan

2003-01-01

354

Wave Energy assessment in the NW Adriatic Sea  

NASA Astrophysics Data System (ADS)

The work aims at evaluating the wave energy resources in the Adriatic Sea (NE region of the Mediterranean Sea), focusing more specifically on the northern-western sector of the basin. In this portion of this shallow semi-enclosed basin, the dominant winds blowing are Bora and Scirocco, both causing high and energetic waves. Bora is a cold and katabatic wind blowing from NE, generally fetch-limited, while Sirocco is warm and wet wind and is coming from SE. The waves climate is reproduced by means of the SWAN model, using the meteorological forcings provided by the operational meteorological model COSMO-I7 (the Italian version of the COSMO Model), a mesoscale model developed in the framework of the COSMO Consortium. The adopted grid size has a 2 km resolution and covers the whole basin. Local comparisons are carried out considering the acquired data at the CNR-ISMAR Acqua Alta tower, located at 10 km off Venice, and by means of remote sensed data (Jason and ENVISAT altimeters), during the years 2010-2011. Comparisons against measurements evidenced that the wave prediction system provides reliable results in terms of significant wave heights, periods and directions. Starting from these considerations, the fields of wave energy are analyzed for the wave conditions typical of three winter months of 2011, during which relevant storms with winds up to 20 m/s and significant wave heights close to 4 m occurred and were registered. The two components of the wave energy transport were then computed using the SWAN model fully coupled with the ocean model ROMS, as implemented in the Coupled Ocean-Atmosphere-Wave-Sediment Transport (COAWST) modeling system. The 2-way data transfer between circulation and wave models was synchronous with ROMS providing current field, free surface elevation, and bathymetry to SWAN. We also considered the influence of current on wave energy running the SWAN model alone. Preliminary results represent a useful step for further investigations that will be spanning longer time periods and/or with increased resolution in the direction of a better understanding of the nearshore dynamics and in the definition of good practices in the field of littoral protection.

Sclavo, M.; Barbariol, F.; Benetazzo, A.; Carniel, S.

2012-04-01

355

Measurement of the Bending Wave Power Flow by the Structural Intensity Technique.  

National Technical Information Service (NTIS)

A literature survey is given on the theory of bending waves and power flow, measurement of the structural intensity, and its applications to machinery and buildings. Based on the known intensity measurement equations, a comprehensive set of frequency doma...

J. Linjama T. Lahti

1989-01-01

356

The oscillating water column wave-energy device  

Microsoft Academic Search

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

D. V. Evans

1978-01-01

357

Suppression of spurious modes in high power travelling wave tubes  

Microsoft Academic Search

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

E. Glass

1982-01-01

358

Enhanced frequency agility of high-power relativistic backward wave oscillators  

Microsoft Academic Search

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

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

1996-01-01

359

Low power High Frequency Surface Wave Radar application for ship detection and tracking  

Microsoft Academic Search

High-frequency (HF) radars are operated in the 3-30 MHz frequency band and are known to cover ranges up to some thousand kilometers. Sky wave over-the-horizon radars (OTHR) utilize reflection by the ionosphere, but they require a transmit power up to 100 kilowatts. Especially for oceanographic applications, low power high frequency surface wave radar (HFSWR) systems have been developed, which use

Anna Dzvonkovskaya; Klaus-Werner Gurgel; Hermann Rohling; Thomas Schlick

2008-01-01

360

Thin-film adhesion measurement using laser-generated high-power surface acoustic wave  

Microsoft Academic Search

A method of the interfacial adhesion measurements utilizing the generation and monitoring of high-power surface acoustic wave has been reported. High-power surface acoustic wave was generated by surface optical breakdown in a transparent dielectric substrate. Modification of the tension-to-shear stresses ratio with film thickness was demonstrated. The normal stress generated at the interface is about one order of magnitude higher

V. Kireev; Y. Liu; Y. Braiman; B. Radhakrishnan; C. H. Hsueh; P. F. Becher

2006-01-01

361

Transient four-wave-mixing spectroscopy on gallium nitride: Energy splittings of intrinsic excitonic resonances  

NASA Astrophysics Data System (ADS)

We present transient and spectrally resolved four-wave-mixing studies on excitonic transitions in GaN with wurtzite structure. Coherent excitation of the A and B excitons results in a pronounced beating with a period of 0.520 ps, corresponding to an A-B splitting of (7.98+/-0.03) meV. A biexcitonic binding energy of (5.7+/-0.3) meV is obtained from the power spectrum of the four-wave-mixing signal.

Zimmermann, R.; Euteneuer, A.; Möbius, J.; Weber, D.; Hofmann, M. R.; Rühle, W. W.; Göbel, E. O.; Meyer, B. K.; Amano, H.; Akasaki, I.

1997-11-01

362

A high-power relativistic backward wave oscillator with a longitudinal slot slow-wave system  

NASA Astrophysics Data System (ADS)

It is established that longitudinal slots in the slow-wave system of a high-current relativistic backward wave oscillator (BWO) can be used as additional means of mode selection and effective absorption of near-wall plasma. Using these properties, it is possible to increase the limiting pulse duration and repetition rate of BWO output radiation pulses.

Goykhman, M. B.; Kladukhin, V. V.; Kladukhin, S. V.; Kovalev, N. F.; Kolganov, N. G.; Khramtsov, S. P.

2014-01-01

363

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

364

Transverse shock wave demagnetization of Nd2Fe14B high-energy hard ferromagnetics  

NASA Astrophysics Data System (ADS)

The action of transverse shock waves (the shock wave propagates across the magnetization vector M) on the magnetic phase state of a Nd2Fe14B high-energy hard ferromagnetic was investigated experimentally. The design of the ferromagnetic sample, which was made as a hollow cylinder, has made it possible to dramatically reduce the amount of the explosive that initiates a transverse shock wave in Nd2Fe14B to 1.0 g (for Nd2Fe14B samples weighing 67.5 g). The results of the experiment have shown that the transverse shock wave propagating through Nd2Fe14B causes "hard ferromagnetic-to-paramagnetic" phase transformation terminating by practically complete demagnetization of Nd2Fe14B. Pulse generators based on the transverse shock wave demagnetization of hollow cylindrical Nd2Fe14B samples with diameter of 25.4 mm and length of 19.1 mm are capable of producing high-voltage pulses [peak voltage of 11.3 kV, full width at half maximum (FWHM) of 4.5 mu]s and high-current pulses (peak current of 1.93 kA, FWHM of 100 mus, peak power of 27.0 kW). The effect of transverse shock wave demagnetization of high-energy hard ferromagnetic, Nd2Fe14B, was detected.

Shkuratov, Sergey I.; Talantsev, Evgueni F.; Dickens, James C.; Kristiansen, Magne

2002-07-01

365

Feasibility of Traveling Wave Direct Energy Conversion of Fission Reaction Fragments  

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

366

Measurements of radiated elastic wave energy from dynamic tensile cracks  

NASA Technical Reports Server (NTRS)

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

Boler, Frances M.

1990-01-01

367

Power Independent Ignition Energy Measurements.  

National Technical Information Service (NTIS)

A portion of the electrical energy supplied to hot-wire ignitable materials is dissipated, largely through thermal conduction, to the unignited portion of the charge and to the containment and igniter system. The remainder of the energy deposited by the i...

J. Mohler

1980-01-01

368

Measurement of acoustic output power in a traveling wave engine  

Microsoft Academic Search

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

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

2006-01-01

369

Energy, environment, and advances in power electronics  

Microsoft Academic Search

The technology of power electronics has gone through rapid technological advancement during the last four decades, and recently, its applications are fast expanding in industrial, commercial, residential, military and utility environments. In the global industrial automation, energy conservation and environmental pollution control trends of the 21st Century, the widespread impact of power electronics is inevitable. The paper begins with a

Bimal K. Bose

2000-01-01

370

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

371

Nonlinear reflectivity of high-power radio waves in the ionosphere  

NASA Astrophysics Data System (ADS)

The results of an experiment to determine the effect of wide-band absorption (WBA) on a radio pump wave causing the WBA are reported. The amplitude of the 5.423 MHz pump wave was measured at a receiver 40 km south of the transmitter at high latitudes. The effective radiated power of the wave was stepped upwards 40 times from 0-260 MW and down again in 9 sec intervals. Several cycles were repeated, and the reflected signal was observed to increase steadily, but increasingly more slowly, up to 40-50% of full power, when the effective reflected signal power began to decrease with increasing signal power. The results indicate the presence of a certain optimum power above which the signal received via the ionosphere will be reduced.

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

1982-02-01

372

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

Microsoft Academic Search

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

M. Greenhow; S. P. White

1997-01-01

373

Power-amplifying strategy in vibration-powered energy harvesters  

NASA Astrophysics Data System (ADS)

A new cantilevered piezoelectric energy harvester (PEH) of which the additional lumped mass is connected to a harmonically oscillating base through an elastic foundation is proposed for maximizing generated power and enlarging its frequency bandwidth. The base motion is assumed to provide a given acceleration level. Earlier, a similar energy harvester employing the concept of the dynamic vibration absorber was developed but the mechanism of the present energy harvester is new because it incorporates a mass-spring system in addition to a conventional cantilevered piezoelectric energy harvesting beam with or without a tip mass. Consequently, the proposed energy harvester actually forms a two-degree-of-freedom system. It will be theoretically shown that the output power can be indeed substantially improved if the fundamental resonant frequencies of each of the two systems in the proposed energy harvester are simultaneously tuned as closely as possible to the input excitation frequency and also if the mass ratio of a piezoelectric energy harvesting beam to the lumped mass is adjusted below a certain value. The performance of the proposed energy harvester is checked by numerical simulation.

Ma, Pyung Sik; Kim, Jae Eun; Kim, Yoon Young

2010-03-01

374

Mini-Scale Power Distribution Network Feeding Trapezoidal-Wave Voltages to Power Electronic Loads with Diode Rectifiers  

NASA Astrophysics Data System (ADS)

This paper proposes a novel three-phase power distribution system feeding trapezoidal voltages to various power electronic loads with diode rectifier front-ends. The network distributes trapezoidal voltages generated by synchronous superposition of wave-shaping voltages onto sinusoidal voltages available from a utility power grid. The power distribution by the trapezoidal voltages allows reducing harmonics of the line currents without electronic switching devices because of a spontaneously widened conduction period of the current waveforms. The reduction of the harmonic currents also contributes to improve total power factor at the load input terminals and efficiency of the power transmission cables. Since the diodes of the rectifiers successively commutate the trapezoidal waves during periods of their flat parts, not only total harmonic distortion of the currents is improved, but also voltage ripple across the dc-buses of the rectifiers can effectively be reduced with less filter capacitors. In addition, the system offers an uninterruptible power supply function by immediately changing its outputs from the wave-shaping voltages to the trapezoidal voltages when interruption occurs in the power grid. In this paper, a prototype of the system is experimentally examined from various angles of operating characteristics and test results are presented to prove feasibility of the proposed system.

Noguchi, Toshihiko; Imoto, Masaru; Sato, Yoshikazu

375

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

376

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

Microsoft Academic Search

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

David C. Fritts; Thomas E. Vanzandt

1993-01-01

377

Measurement of acoustic output power in a traveling wave engine.  

PubMed

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

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

2006-12-22

378

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

379

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

380

Enhanced frequency agility of high-power relativistic backward wave oscillators  

SciTech Connect

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

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

1996-06-01

381

Concurrent Measurements of the Directional Spectra of Microseismic Energy and Surface Gravity Waves.  

National Technical Information Service (NTIS)

This paper presents concurrent measurements of surface wave directional spectra and double-frequency, long-wave microseisms. Long-wave energy rapidly develops during periods of shifting winds which create bidirectional sea states. Bidirectional sea states...

T. Nye T. Yamamoto

1994-01-01

382

Space solar power - An energy alternative  

NASA Technical Reports Server (NTRS)

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

Johnson, R. W.

1978-01-01

383

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

Microsoft Academic Search

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

David C. Fritts; Wentong Lu

1993-01-01

384

Output power enhancement of a palmtop terahertz-wave parametric generator  

Microsoft Academic Search

Broadband terahertz (THz) waves were generated by optical parametric processes based on laser light scattering from the polariton mode of a nonlinear crystal. By using the parametric oscillation of a MgO-doped LiNbO3 crystal pumped by a nanosecond Q-switched Nd:YAG laser, we have realized a broadband, high-energy and compact THz-wave source. We report the development of a THz-wave parametric generator (TPG)

Shin'ichiro Hayashi; Hiroaki Minamide; Tomofumi Ikari; Yuichi Ogawa; Jun-Ichi Shikata; Hiromasa Ito; Chiko Otani; Kodo Kawase

2007-01-01

385

An energy-adaptive MPPT power management unit for micro-power vibration energy harvesting  

Microsoft Academic Search

A batteryless power management unit (PMU) that manages harvested low-level vibration energy from a piezoelectric device for a wireless sensor node is presented. An energy-adaptive maximum power point tracking (EA-MPPT) scheme is proposed that allows the PMU to activate different operation modes according to the available power level. The harvested energy is processed by an ac-dc voltage doubler followed by

Jun Yi; Feng Su; Yat-hei Lam; Wing-hung Ki; Chi-ying Tsui

2008-01-01

386

Solar energy converter using surface plasma waves  

NASA Technical Reports Server (NTRS)

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

Anderson, L. M. (inventor)

1984-01-01

387

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

388

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

389

Saving Energy Through Advanced Power Strips (Poster)  

SciTech Connect

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

Christensen, D.

2013-10-01

390

Gravitational wave frequencies and energies in hypernovae  

Microsoft Academic Search

A torus develops a state of suspended accretion against a magnetic wall\\u000aaround a rapidly rotating black hole formed in core-collapse hypernovae. It\\u000ahereby emits about 10% of the black hole spin-energy in gravitational radiation\\u000afrom a finite number of multipole mass moments. We quantify the relation\\u000abetween the frequency of quadrupole gravitational radiation and the energy\\u000aoutput $E_w$ in

2002-01-01

391

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

392

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

393

Advances in the control of a “smart tube” high power backward wave oscillator  

Microsoft Academic Search

Previous accomplishments pertaining to the control of various parameters of an intense beam-driven relativistic backward wave oscillator (BWO) include maintaining a specified or desired output power over a determined frequency bandwidth, and maintaining a constant frequency over a wide range of power. This was accomplished using an iterative learning control (ILC) algorithm that yielded the appropriate input variables for the

E. Schamiloglu; G. T. Park; V. S. Soualian; C. T. Abdallah; F. Hegeler

1999-01-01

394

Nonlinear behavior of electric power transmission through an elastic wall by acoustic waves and piezoelectric transducers  

Microsoft Academic Search

Weakly nonlinear behavior of electric power transmission through an elastic wall by piezoelectric transducers and acoustic waves near resonance is studied based on the cubic theory of nonlinear electroelasticity. An approximate analytical solution is obtained. Output voltage is calculated and plotted. Basic nonlinear behaviors of the power transmission structure are examined. It is found that near nonlinear resonance the electrical

Zengtao Yang; Jiashi Yang; Yuantai Hu

2008-01-01

395

LABORATORY AND WORKSHOP NOTES: A bakeable magnet for high power travelling wave tubes  

Microsoft Academic Search

This paper describes a new type of electromagnet for high power travelling wave tubes. The coils are wound on the body of the tube immediately after construction and are able to withstand the temperature of 450° c at which the tube is processed. The design achieves a great saving in weight and power and presents a neat packaged tube.

A. Thomas

1963-01-01

396

Nearly degenerate four-wave mixing in laser diodes subject to strong probe injection power  

Microsoft Academic Search

Nearly degenerate four-wave mixing (FWM) in above-threshold laser diodes with symmetric or asymmetric facet reflectivities, subject to strong probe injection power, is investigated theoretically, taking into account the effects of pump depletion, carrier diffusion, gain saturation, gain compression, total power dependence of the gain and coupling coefficients as well as the longitudinal dependence of the nonlinear interaction. It is shown

J. M. Tang; K. A. Shore

1998-01-01

397

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

398

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

NASA Technical Reports Server (NTRS)

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

Korneva, L. A.

1975-01-01

399

Energy Servers Deliver Clean, Affordable Power  

NASA Technical Reports Server (NTRS)

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

2010-01-01

400

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

SciTech Connect

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

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

2006-01-01

401

Power-flow formulation of a ray approach to the modelling of inhomogeneous waves  

NASA Astrophysics Data System (ADS)

In this paper, we elaborate on quite a simple analytical framework for the physically intelligible principle of a ray description of inhomogeneous wavefields on the basis of the generic properties of active and reactive wave power flows. While being very close to traditional geometric optics (GO) in the limit of lossless media, in substantially non-Hermitian systems this approach turns out to be a distinct method capable of keeping up ray trajectories in a real-valued domain. We also demonstrate that the ray method based on power-flow analysis is mostly free from the standard limitations of GO. In this regard, the proper use of the ray-tracing technique can be justified for modelling a wide range of non-regular wave phenomena if wave power transport is under consideration. The paraxial equations are shown to comply with the power-flow formulation, thus finding an extended range of applicability.

Tereshchenko, M.; Castejón, F.; Pavlov, S.; Cappa, A.

2011-08-01

402

Excitation of small-scale waves in the F region of the ionosphere by powerful HF radio waves  

Microsoft Academic Search

Ionospheric small-scale waves in the F region, initiated by heating facilities in Nizhniy Novgorod, have been studied by the method of field-aligned scattering of diagnostic HF radio signals. Experimental data have been obtained on the radio path Kiev–N. Novgorod–St. Petersburg during heating campaigns with heater radiated power ERP = 20 MW and 100 MW. Observations of scattered HF signals have

N. F. Blagoveshchenskaya; M. Yu. Chernyshev; V. A. Kornienko

1998-01-01

403

Excitation of small-scale waves in the F region of the ionosphere by powerful HF radio waves  

Microsoft Academic Search

Ionospheric small-scale waves in the F region, initiated by heating facilities in Nizhniy Novgorod, have been studied by the method of field-aligned scattering of diagnostic HF radio signals. Experimental data have been obtained on the radio path Kiev-N. Novgorod-St. Petersburg during heating campaigns with heater radiated power ERP = 20 MW and 100 MW. Observations of scattered HF signals have

N. F. Blagoveshchenskaya; M. Y. Chernyshev; V. A. Kornienko

1998-01-01

404

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

405

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

406

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

SciTech Connect

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

Yamamoto, Kazuhiro; Hayakawa, Hideaki; Okada, Atsushi; Uchiyama, Takashi; Miyoki, Shinji; Ohashi, Masatake; Kuroda, Kazuaki; Kanda, Nobuyuki; Tatsumi, Daisuke; Tsunesada, Yoshiki [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa, Chiba 277-8582 (Japan); Department of Physics, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka, Osaka 558-8585 (Japan); National Astronomical Observatory of Japan, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan)

2008-07-15

407

Negative energy waves in a plasma with structured magnetic fields  

Microsoft Academic Search

The properties of a plasma containing structured magnetic fields (magnetic tubes) in the presence of shear flows of matter along the magnetic tubes are investigated. It is shown that the presence of sufficiently fast flows leads to the appearance of a number of new effects: the production of negative-energy waves, the reversal of the radiative damping sign, the development of

M. P. Riutova

1988-01-01

408

Gas concentration cells for the conversion of ocean wave energy  

Microsoft Academic Search

The concept of using electrochemical gas concentration cells to convert the mechanical potential energy of ocean waves to electricity using a taut-moored buoy is analyzed. Several idealized embodiments are discussed and one of these is shown to have particular merit. Some results obtained in an experimental program aimed at developing such a system are described. In particular, an electrochemical cell

R. E. Salomon; S. M. Harding

1979-01-01

409

Flap type weather proof ocean wave energy converter  

Microsoft Academic Search

A wave energy extraction system is presented that consists of one centrally located main body and two cylindrical flaps situated on each side of the main body and joined to it by two linkage arms. It is noted that this system can be operated not only on the ocean surface but also at submerged level. Attention is given to the

F. H. Hsu

1979-01-01

410

Turbine speed control for an ocean wave energy conversion system  

Microsoft Academic Search

In this work, a hydraulic turbine speed governor is proposed in view of its application in an isolated electric generation system based on an ocean wave energy converter (WEC). The proposed strategy is based on cascade closed-loop control combined with feedforward of load disturbances. The main characteristics of a WEC are presented and a dynamic model of the generating unit

Paula B. Garcia-Rosa; J. P. V. S. Cunha; Fernando Lizarralde

2009-01-01

411

Temporal Energy Cascading in the Beat Wave Accelerator  

Microsoft Academic Search

A preliminary analytic study of the temporal evolution of the beat wave accelerator (BWA) has been conducted. It was found that while energy cascading is crucial to the interpretation of current simulations, it will be less important in an actual device where the existing simple fluid model will be adequate.

S. H. Batha; C. J. McKinstrie

1987-01-01

412

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

413

The method of imbedded Lagrangian element to estimate wave power absorption by some submerged devices  

NASA Astrophysics Data System (ADS)

A simple approach is described to estimate the wave power absorption potential of submerged devices known to cause wave focusing and flow enhancement. In particular, the presence of a flow-through power take-off (PTO) system, such as low-head turbines, can be accounted for. The wave radiation characteristics of an appropriately selected Lagrangian element (LE) in the fluid domain are first determined. In the limit of a vanishing mass, the LE reduces to a patch of distributed normal dipoles. The hydrodynamic coefficients of this virtual object are then input in a standard equation of motion where the effect of the PTO can be represented, for example, as a dashpot damping term. The process is illustrated for a class of devices recently proposed by Carter and Ertekin (2011), although in a simplified form. Favorable wave power absorption is shown for large ratios of the LE wave radiation coefficient over the LE added mass coefficient. Under optimal conditions, the relative flow reduction from the PTO theoretically lies between 0.50 and , with lower values corresponding to better configurations. Wave power capture widths, the sensitivity of results to PTO damping and sample spectral calculations at a typical site in Hawaiian waters are proposed to further illustrate the versatility of the method.

Nihous, Gérard C.

2014-06-01

414

Forecasting ocean wave energy: Tests of time-series models  

Microsoft Academic Search

This paper evaluates the ability of time-series models to predict the energy from ocean waves. Data sets from four Pacific Ocean sites are analyzed. The energy flux is found to exhibit nonlinear variability. The probability distribution has heavy tails, while the fractal dimension is non-integer. This argues for using nonlinear models. The primary technique used here is a time-varying parameter

Gordon Reikard

2009-01-01

415

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

416

Energy storage options for space power  

NASA Astrophysics Data System (ADS)

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

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

417

Effects of Wave Energy Converter (WEC) Arrays on Wave, Current, and Sediment Circulation  

NASA Astrophysics Data System (ADS)

The characterization of the physical environment and commensurate alteration of that environment due to Wave Energy Conversion (WEC) devices, or arrays of devices, must be understood to make informed device-performance predictions, specifications of hydrodynamic loads, and environmental evaluations of eco-system responses (e.g., changes to circulation patterns, sediment dynamics, and water quality). Hydrodynamic and sediment issues associated with performance of wave-energy devices will primarily be nearshore where WEC infrastructure (e.g., anchors, piles) are exposed to large forces from the surface-wave action and currents. Wave-energy devices will be subject to additional corrosion, fouling, and wear of moving parts caused by suspended sediments in the water column. The alteration of the circulation and sediment transport patterns may also alter local ecosystems through changes in benthic habitat, circulation patterns, or other environmental parameters. Sandia National Laboratories is developing tools and performing studies to quantitatively characterize the environments where WEC devices may be installed and to assess potential affects to hydrodynamics and local sediment transport. The primary tools are wave, hydrodynamic, and sediment transport models. To ensure confidence in the resulting evaluation of system-wide effects, the models are appropriately constrained and validated with measured data where available. An extension of the US EPA's EFDC code, SNL-EFDC, provides a suitable platform for modeling the necessary hydrodynamics;it has been modified to directly incorporate output from a SWAN wave model of the region. Model development and results are presented. In this work, a model is exercised for Monterey Bay, near Santa Cruz where a WEC array could be deployed. Santa Cruz is located on the northern coast of Monterey Bay, in Central California, USA. This site was selected for preliminary research due to the readily available historical hydrodynamic data (currents and wave heights, periods, and directions), sediment characterization data, and near-shore bathymetric data. In addition, the region has been under evaluation for future ocean energy projects. The modeling framework of SWAN and SNL-EFDC combined with field validation datasets allows for a robust quantitative description of the nearshore environment within which the MHK devices will be evaluated. This quantitative description can be directly incorporated into environmental impact assessments to eliminate guesswork related to the effects of the presence of large-scale arrays. These results can be used to design more efficient arrays while minimizing impacts on the nearshore environments. Further investigations into fine-scale scour near the structures will help determine if these large-scale results show that, in fact, there is deposition adjacent to the arrays, which could have design implications on anchorage and cabling systems.

Ruehl, K.; Roberts, J. D.; Jones, C.; Magalen, J.; James, S. C.

2012-12-01

418

Design of wide-band gyro-twystrons for high power millimeter wave radar applications  

Microsoft Academic Search

Summary form only given. The Naval Research Laboratory is currently investigating gyro-twystrons as high-power, wideband sources for millimeter wave radars. For many radar applications, the gyro-twystron configuration represents a suitable compromise between the high power, narrow band gyro-klystron and the lower power, broadband gyro-TWT. A non-linear simulation code was used to design two gyro-twystrons, the first in Ka-band and the

M. Blank; P. E. Latham; B. Levush; B. G. Danly

1996-01-01

419

Millimeter-wave radar phenomenology of power lines and a polarimetric detection algorithm  

Microsoft Academic Search

The radar phenomenology of high-voltage power lines and cables is studied for examining the feasibility of detecting power lines along the path of a low-flying aircraft using a millimeter-wave radar system. For this purpose, polarimetric backscatter measurements of power line samples of different diameters and strand arrangements were performed over a wide range of incidence angles with very fine increments

Kamal Sarabandi

1999-01-01

420

Energy Delivery to Cliffs from Waves, Tides and Storms  

NASA Astrophysics Data System (ADS)

The energy delivered to hard rock cliffs from waves, tides and storms is acknowledged as a key control of cliff erosion, due to the influence on the effectiveness of mechanical and hydraulic processes. The direct impact and variability of wave energy and its influence on rock cliffs remains poorly constrained. Questions remain around the relative impact that waves, tides and storms have on energy delivery to the coast and therefore on cliff evolution. The results of this paper begin to unpick these three influences. These results are made more significant in terms of understanding the future likely impact of sea-level change, but more widely in clarifying the relative significance of marine to sub-aerial weathering processes in controlling cliff failure and rocky coast evolution. It has been demonstrated that wave impact against cliffs results in microseismic ground motions, which can be used as a proxy for energy delivery to the cliff mass. This paper presents the findings of a study that exploits data from a 10 instrument 3D seismometer array, combined with an intensive program of monitoring of marine and aerial conditions on and near the cliff section. The study site on the coast of northeast England, consists of numerous strata of Jurassic mudstones, sandstones and shales. The high tidal range and exposure to frequent stormy conditions results in wide day-to-day variations in environmental conditions. The results enable assessment of the sensitivity of rocky cliff ground motion to wave characteristics such as height and period, tidal characteristics including levels and durations of inundation, and wind and rainfall events, explored using spectral and wavelet analysis. The results provide a quantification of the relative energy delivery of these different forcing mechanisms, and hence provide insight of likely cliff responses to future climate change scenarios related to combined changes in storm severity and sea-level.

Norman, E. C.; Rosser, N. J.; Lim, M.; Petley, D. N.

2009-12-01

421

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

422

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

423

Fractal ladder models and power law wave equations  

PubMed Central

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

Kelly, James F.; McGough, Robert J.

2009-01-01

424

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

425

Advanced applications and solid-state power sources for millimeter-wave systems  

Microsoft Academic Search

Attention is given to the design features and performance capabilities of mm-wave systems for smart munitions and minimissile guidance, communications, fire control, and radiometry, as well as to the solid state power sources, such as IMPATT diodes, which have made these integrated, light-weight systems possible. The majority of applications foreseen for mm-wave electronics are subsumed under advanced radar systems, including

G. R. Thoren

1984-01-01

426

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

427

A study on applications of energy storage for the wind power operation in power systems  

Microsoft Academic Search

Energy storage system (ESS) has been studied as a high-tech solution for managing power flows from wind turbine generator (WTG), and making them be competitive energy sources without putting power systems at risk. This paper illustrates possible applications of the energy storage for the wind power operating in power systems focusing on its short-duration prospective. Employing a sample power system,

Kyung Soo Kook; Keith J. McKenzie; Yilu Liu; Stan Atcitty

2006-01-01

428

NSF/Tokyo Report: Report On Ocean Wave Energy Conversion Projects  

NSF Publications Database

Title: NSF/Tokyo Report: Report On Ocean Wave Energy Conversion Projects Date: April 23, 1998 The ... Report On Ocean Wave Energy Conversion Projects Summary This report presents a brief overview of the ...

429

A self-regulating heat pump to utilize wind and wave energy sources  

SciTech Connect

This paper describes the efficiency of using shaft work to drive a heat pump and the utilization of variable shaft work to upgrade heat from a source at near- constant temperature. A prototype heat pump is described that enables heat from an ambient source at {approximately} 20{degrees}C to be delivered to a load at {approximately} 100{degrees}C by a vapor compression system working with variable power input, such as that deriving from wind or wave energy. The design incorporates features that enable power inputs from 0.3-3 kW to be harnessed, corresponding to the wave energy in a 0.1-m width of usable wavefront, or the wind energy abstracted by a rotor of 2.5-m diameter in windspeeds of 7-15 m/s. A c.o.p. of {approximately}3 may be obtained over this range of power input. Thus the heat output is equivalent to that obtainable directly from an energy conversion device of three times the size.

Pritchard, C.; Low, R. (Dept. of Chemical Engineering, Univ. of Edinburgh, Edinburgh (GB))

1990-01-01

430

Sound power spectrum and wave drag of a propeller in flight  

NASA Technical Reports Server (NTRS)

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

Hanson, D. B.

1989-01-01

431

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

NASA Technical Reports Server (NTRS)

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

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

2008-01-01

432

75 FR 21289 - Oregon Wave Energy Partners I, LLC; Notice of Preliminary Permit Application Accepted for Filing...  

Federal Register 2010, 2011, 2012, 2013

...Project No. 12749-002] Oregon Wave Energy Partners I, LLC; Notice of Preliminary...2010. On March 2, 2010, Oregon Wave Energy Partners I, LLC filed an application...Charles F. Dunleavy, Oregon Wave Energy Partners I, LLC, 1590 Reed...

2010-04-23

433

Nuclear power: an essential energy. [Conference paper  

SciTech Connect

Dr. Agnew notes that the public fails to remember that the electric utilities and equipment manufacturers did not invent nuclear energy; they only choose whether or not to use it to generate power. The effort to regain world leadership in nuclear energy will require recognizing that the rest of the world needs it too. Opposition to the use of nuclear power has been politically effective, in spite of the need to move to a non-petroleum fuel base and without coming up with a viable alternative. The nuclear industry responded to the Three Mile Island accident by taking steps to improve reactor safety, but the industry continues to be threatened because of the suspended reprocessing and breeder programs. The industry must make a compelling case for energy independence to persuade the public that all energy sources, including nuclear, must be developed. (DCK)

Agnew, H.M.

1980-01-01

434

Wave energy and swimming performance shape coral reef fish assemblages.  

PubMed

Physical factors often have an overriding influence on the distribution patterns of organisms, and can ultimately shape the long-term structure of communities. Although distribution patterns in sessile marine organisms have frequently been attributed to functional characteristics interacting with wave-induced water motion, similar evidence for mobile organisms is lacking. Links between fin morphology and swimming performance were examined in three diverse coral reef fish families from two major evolutionary lineages. Among-habitat variation in morphology and performance was directly compared with quantitative values of wave-induced water motion from seven coral reef habitats of different depth and wave exposure on the Great Barrier Reef. Fin morphology was strongly correlated with both field and experimental swimming speeds in all three families. The range of observed swimming speeds coincided closely with the magnitude of water velocities commonly found on coral reefs. Distribution patterns in all three families displayed highly congruent relationships between fin morphology and wave-induced water motion. Our findings indicate a general functional relationship between fin morphology and swimming performance in labriform-swimming fishes, and provide quantitative evidence that wave energy may directly influence the assemblage structure of coral reef fishes through interactions with morphology and swimming performance. PMID:15888415

Fulton, C J; Bellwood, D R; Wainwright, P C

2005-04-22

435

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

NASA Astrophysics Data System (ADS)

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 ˜g2?-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.

Kartashova, Elena

2012-10-01

436

Novel Nuclear Powered Photocatalytic Energy Conversion  

SciTech Connect

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

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

2005-08-29

437

Energy recovery for low-power CMOS  

Microsoft Academic Search

Energy recovery, as a means to trade off power dissipation for performance in CMOS logic circuits, is analyzed and investigated. A mathematical model is presented to estimate the efficiency for two energy-recovery approaches under varying conditions of voltage swing, transition time, and MOS device parameters. This model can be directly compared to the well-known model for supply-voltage scaling, which is

William C. Athas; Nestoras Tzartzanis

1995-01-01

438

Electromechanical wave propagation in large electric power systems  

Microsoft Academic Search

An electrical power network consisting of generators and transmission lines is treated as a continuum system. The application of the limit of zero generator spacing, with finite rotor inertia and transmission line impedance per unit length, yields a nonlinear partial differential equation in time and two spatial dimensions for the rotor phase angle. The equation is a nonlinear version of

James S. Thorp; Charles E. Seyler; Arun G. Phadke

1998-01-01

439

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

440

Advanced applications and solid-state power sources for millimeter-wave systems  

NASA Astrophysics Data System (ADS)

Attention is given to the design features and performance capabilities of mm-wave systems for smart munitions and minimissile guidance, communications, fire control, and radiometry, as well as to the solid state power sources, such as IMPATT diodes, which have made these integrated, light-weight systems possible. The majority of applications foreseen for mm-wave electronics are subsumed under advanced radar systems, including secure and interference-free military radars, high resolution and imaging radars, space object and target characteristics identification, and jet engine exhaust and cannon blast detection. Attention is given to silicon, GaAs, and InP IMPATT diodes and their power combiners.

Thoren, G. R.

1984-12-01

441

Blast Shock Wave Mitigation Using the Hydraulic Energy Redirection and Release Technology  

PubMed Central

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.

Chen, Yun; Huang, Wei; Constantini, Shlomi

2012-01-01

442

Prediction of ocean wave energy from meteorological variables by fuzzy logic modeling  

Microsoft Academic Search

Ocean wave energy which is one of the promising renewable energy types has a direct relationship with the wave climate. The purpose of this study is to investigate the relationship between ocean wave energy and meteorological variables such as wind speed, air temperature, and sea temperature. It was shown that fuzzy logic modeling of these variables provides the possible non-linear

Mehmet Özger

2011-01-01

443

On transport of energy, momentum, orbital angular momentum and self-angular momentum of electromagnetic wave in dispersal media  

NASA Astrophysics Data System (ADS)

The transport equations for energy, momentum, orbital angular momentum and self-angular momentum of the electromagnetic wave packet propagating in the weakly absorbing homogeneous stationary anisotropic and gyrotropic medium with temporal and spacial dispersion have been obtained. These equations contain terms up to second order expansion in series for values lambda/L and Omega/omega (here lambda and omega are the wave length and wave frequency, L and i/Omega-the characteristic length and time of the wave amplitude change). It has been shown that the self-angular momentum (spin) conservation law is true only for transversal waves with circular polarization. Expressions for spin density, its flux, and power losses have been determined.

Kurochkin, Yu. A.; Stepanov, K. N.

444

Wind Powering America: Wind Energy Videos  

DOE Data Explorer

Wind Powering America is a nationwide initiative designed to increase the use of wind energy across the United States by working with regional stakeholders. A list of videos developed by and for the program includes interviews, short news clips, and documentary-like programs.

445

Science of NHL Hockey: Work, Energy & Power  

NSDL National Science Digital Library

The slapshot is one of the fastest projectiles in team sports. In order to generate a 100 mile-per-hour (160 kph) slapper, NHL players depend on three important physics concepts: work, energy and power. "Science of NHL Hockey" is a 10-part video series funded by the National Science Foundation and produced in partnership with the National Hockey League.

Learn, Nbc

2010-10-07

446

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

447

Energy scavenging technique for powering wireless sensors  

Microsoft Academic Search

A capacitive scavenging device is proposed to extract energy from the electric field that surrounds the equipment in a substation. Related research has shown that switching techniques can be used to increase the useful power obtained. An experiment has been set up by putting two parallel plates of 10 cm radius in a uniform AC electric field up to 20

M. Zhu; A. Reid; S. Finney; M. Judd

2008-01-01

448

Power quality for energy efficient buildings  

Microsoft Academic Search

This paper presents results from a PQ audit conducted in an IT-intensive modern office building. Some of the mayor objectives of the PQ study were: detecting the main involved disturbances by PQ monitoring, identifying the power disturbances root causes, characterizing the electromagnetic compatibility level of equipments and installation and providing guidelines for implementing energy-efficiency solutions. It has been found that

A. Moreno-Munoz; J. M. Flores-Arias; A. Gil-de-Castro

2009-01-01

449

Phase locking of high power relativistic backward wave oscillator using priming effect  

NASA Astrophysics Data System (ADS)

The phase-locking approach using the priming effect is developed for high power relativistic backward wave oscillators (RBWO). A plasma switch is conceived to avoid the feedback effect. In experiment, multicavity RBWO of 200 MW with the 73 MHz half power bandwidth is phase-locked under the injection power ratio 0.044 for the frequency separation of 20 MHz. We found that it takes more time to reach stable phase-locking than to achieve saturation of RBWO generation. The external signal of higher power results in the longer time duration of phase locking. Besides phase-locking, the priming effect leads to longer microwave pulse duration.

Teng, Yan; Song, Wei; Sun, Jun; Xiao, Renzhen; Song, Zhimin; Zhang, Ligang; Zhang, Zhiqiang; Zhang, Lijun; Zhang, Yuchuan; Li, Jiawei; Fang, Jinyong

2012-02-01

450

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

451

Modified Tunneladder Slow-Wave Structures for High-Power Millimeter-Wave TWTs  

Microsoft Academic Search

In this paper, five modified Tunneladder slow-wave structures (SWS), the ridge-loaded stub-supported meander line with circular\\u000a electron tunnel (CET-RSML), ring-plane frame line (RPFL), the ridge-loaded thick ladder line (RLTLL), the ridge-loaded pole-piece\\u000a folded-waveguide circuit (RLPFWL), and the double-period Tunneladder line (DPTL) were discussed. The dispersion characteristics\\u000a and the interaction impedances of the five modified Tunneladder SWS were calculated by simulation

Hairong Yin; Gong Yubin; Wei Yuanyu; Lu Zhigang; Huang Mingzhi; Wang Wenxiang

2007-01-01

452

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

453

OWC wave energy devices with air flow control  

Microsoft Academic Search

A theoretical model is developed to simulate the energy conversion, from wave to turbine shaft, of an oscillating-water-column (OWC) plant equipped with a Wells air-turbine and with a valve (in series or in parallel with the turbine) for air-flow control. Numerical simulations show that the use of a control valve, by preventing or reducing the aerodynamic stall losses at the

A. F. de O. Falcão; P. A. P. Justino

1999-01-01

454

A hybrid MAC protocol design for energy-efficient very-high-throughput millimeter wave, wireless sensor communication networks  

NASA Astrophysics Data System (ADS)

This paper presents an energy-efficient Medium Access Control (MAC) protocol for very-high-throughput millimeter-wave (mm-wave) wireless sensor communication networks (VHT-MSCNs) based on hybrid multiple access techniques of frequency division multiplexing access (FDMA) and time division multiplexing access (TDMA). An energy-efficient Superframe for wireless sensor communication network employing directional mm-wave wireless access technologies is proposed for systems that require very high throughput, such as high definition video signals, for sensing, processing, transmitting, and actuating functions. Energy consumption modeling for each network element and comparisons among various multi-access technologies in term of power and MAC layer operations are investigated for evaluating the energy-efficient improvement of proposed MAC protocol.

Jian, Wei; Estevez, Claudio; Chowdhury, Arshad; Jia, Zhensheng; Wang, Jianxin; Yu, Jianguo; Chang, Gee-Kung

2010-12-01

455

Voltage scheduling for low power/energy  

NASA Astrophysics Data System (ADS)

Power considerations have become an increasingly dominant factor in the design of both portable and desk-top systems. An effective way to reduce power consumption is to lower the supply voltage since voltage is quadratically related to power. This dissertation considers the problem of lowering the supply voltage at (i) the system level and at (ii) the behavioral level. At the system level, the voltage of the variable voltage processor is dynamically changed with the work load. Processors with limited sized buffers as well as those with very large buffers are considered. Given the task arrival times, deadline times, execution times, periods and switching activities, task scheduling algorithms that minimize energy or peak power are developed for the processors equipped with very large buffers. A relation between the operating voltages of the tasks for minimum energy/power is determined using the Lagrange multiplier method, and an iterative algorithm that utilizes this relation is developed. Experimental results show that the voltage assignment obtained by the proposed algorithm is very close (0.1% error) to that of the optimal energy assignment and the optimal peak power (1% error) assignment. Next, on-line and off-fine minimum energy task scheduling algorithms are developed for processors with limited sized buffers. These algorithms have polynomial time complexity and present optimal (off-line) and close-to-optimal (on-line) solutions. A procedure to calculate the minimum buffer size given information about the size of the task (maximum, minimum), execution time (best case, worst case) and deadlines is also presented. At the behavioral level, resources operating at multiple voltages are used to minimize power while maintaining the throughput. Such a scheme has the advantage of allowing modules on the critical paths to be assigned to the highest voltage levels (thus meeting the required timing constraints) while allowing modules on non-critical paths to be assigned to lower voltage levels (thus reducing the power consumption). A polynomial time resource and latency constrained scheduling algorithm is developed to distribute the available slack among the nodes such that power consumption is minimum. The algorithm is iterative and utilizes the slack based on the Lagrange multiplier method.

Manzak, Ali

2001-07-01

456

A High-Power Backward-Wave Oscillator Driven by a Relativistic Electron Beam  

Microsoft Academic Search

A high-power backward-wave oscillator (BWO) has been constructed that is driven by a relativistic electron beam (REB). A typical electron beam of 2-4 kA is accelerated across a diode potential of 650-800 kV and then guided through a section of corrugated transmission line by an axial magnetic field of 5-15 kG. Peak microwave powers of 100-200 MW have been observed

R. Alan Kehs; Alan Bromborsky; B. G. Ruth; S. E. Graybill; W. W. Destler; Y. C. Carmel; M. C. Wang

1985-01-01

457

Observation of Chaotic Dynamics in a Powerful Backward-Wave Oscillator  

Microsoft Academic Search

Self-modulation regimes of generation in a powerful 10-mus X-band backward-wave oscillator were studied theoretically and experimentally. The sequence of the self-modulation patterns and corresponding bifurcation values observed as the current was increased were in good agreement with the results of simulations. It was found that at a current of 120A chaotic self-modulation set in at a power of 2MW and

N. S. Ginzburg; N. I. Zaitsev; E. V. Ilyakov; I. S. Kulagin; Yu. V. Novozhilova; R. M. Rozenthal; A. S. Sergeev

2002-01-01

458

High-power continuous-wave operation of quantum-cascade lasers up to 60°C  

Microsoft Academic Search

High-temperature high-power continuous-wave (CW) operation of high-reflectivity-coated 12-?m-wide quantum-cascade lasers emitting at ? = 6 ?m with a thick electroplated Au top contact layer is reported for different cavity lengths. For a 3-mm-long laser, the CW optical output powers of 381 mW at 293 K and 22 mW at maximum operating temperature of 333 K (60°C) are achieved with threshold

J. S. Yu; A. Evans; J. David; L. Doris; S. Slivken; M. Razeghi

2004-01-01

459

Room temperature continuous wave operation of quantum cascade lasers with watt-level optical power  

Microsoft Academic Search

We demonstrate quantum cascade lasers at an emitting wavelength of 4.6 mum, which are capable of room temperature, high power continuous wave (cw) operation. Buried ridge geometry with a width of 9.8 mum was utilized. A device with a 3 mm cavity length that was epilayer-down bonded on a diamond submount exhibited a maximum output power of 1.3 W at

Y. Bai; S. R. Darvish; S. Slivken; W. Zhang; A. Evans; J. Nguyen; M. Razeghi

2008-01-01

460

A radar cross-section model for power lines at millimeter-wave frequencies  

Microsoft Academic Search

The knowledge of radar backscatter characteristics of high-voltage power lines is of great importance in the development of a millimeter-wave wire detection system. In this paper, a very high-frequency technique based on an iterative physical optics approach is developed for predicting polarimetric radar backscattering behavior of power lines of arbitrary strand arrangement. In the proposed scattering model the induced surface

K. Sarabandi

2003-01-01

461

Gain and efficiency studies of a high power travelling wave tube amplifier  

Microsoft Academic Search

The results of measurements on the gain and efficiency of a high power travelling wave tube amplifier powered by a 850 keV, 0.8-1.6 kA, 100 nsec pencil electron beam are reported. The amplifier operates in the TM01 mode and is driven by a 250 kW magnetron. Gains of up to 35 dB and efficiencies of 11 percent have been achieved

D. Shiffler; John A. Nation; J. D. Ivers; G. Kerslick

1990-01-01

462

High-Power Test of a Fast Switch and Combiner for Millimetre Wave Beams  

Microsoft Academic Search

Fast switches for high-power millimeter waves are of interest for electron cyclotron resonance heating (ECRH) systems as they allow sharing of the installed power between different types of launchers or different applications, whichever is given priority during a plasma discharge. The switching can be controlled electronically without moving parts by a small frequency-shift keying of the gyrotron (some 10s of

V. Erckmann; W. Kasparek; M. Petelin; D. Shchegolkov; ECRH Groups

2009-01-01

463

The 230W Traveling Wave Tube Amplifier (TWTA) power supply design  

NASA Astrophysics Data System (ADS)

The electronic power conditioner (EPC) design for 230W RF 12 GHz traveling wave tubes is presented. Bus and tube interface problems, the technological aspects versus the very severe environmental requirements, and the protection philosophy are discussed. The EPC has to handle very high power (600 W), to provide outputs voltages up to 7.5 kV, and to guarantee high stability of output parameters inside a very large operating temperature range (minus 35 to plus 70 C). Efficiency is 87%.

Gasparini, A.; Bonati, A.

1985-05-01

464

Saturation and power law dependence of nonlinear waves guided by a single interface  

Microsoft Academic Search

The formalism recently developed by Langbein et al. (1985) is applied to study the effects of saturation and nonquadratic field dependences on waves guided by the interface between a self-focusing and normal dielectric medium. The power dependences of the propagation constant and field disributions are calculated for both