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1

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

2

Power inversion design for ocean wave energy harvesting  

NASA Astrophysics Data System (ADS)

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

Talebani, Anwar N.

3

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

4

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

5

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

6

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

E-print Network

challenges need to be explored through alternative, renewable and clean energy sources to enable a diverse energy demand is increasing at an alarming rate, and producing electricity from alternative or renewablePredictive Power Control of Doubly-Fed Induction Generator for Wave Energy Converters M.S. Lagoun1

Paris-Sud XI, Université de

7

Supercapacitor testing for power smoothing in a variable speed offshore Wave Energy Converter  

Microsoft Academic Search

This paper investigates power smoothing in a full-scale offshore Oscillating Water Column (OWC) Wave Energy Converter (WEC) by integrating supercapacitors (SCs) with the inertia of a Wells turbine controlled at variable speed. A Simulink model is developed for the WEC system utilising sea state data and a SC system is sized to smooth and reduce the grid peak power for

Donal B. Murray; J. G. Hayes; M. G. Egan; D. L. O'Sullivan

2011-01-01

8

Complementary Control of Oscillating Water Column-Based Wave Energy Conversion Plants to Improve the Instantaneous Power Output  

Microsoft Academic Search

In this paper, an oscillating water column-based wave energy conversion plant is modeled and controlled by means of two complementary control strategies in order to improve the conver- sion of wave energy into electric power. This wave power generation system consists of a capture chamber, a Wells turbine, and an in- duction generator. The improvement relays on the implementation of

M. Alberdi; M. Amundarain; A. J. Garrido; I. Garrido; O. Casquero; M. De la Sen

2011-01-01

9

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

10

Water wave energy transducer  

Microsoft Academic Search

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

Lamberti

1980-01-01

11

Wave Power Demonstration Project at Reedsport, Oregon  

SciTech Connect

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

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

2013-10-21

12

Wave action power plant  

SciTech Connect

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

Lucia, L.V.

1982-03-16

13

Wave energy converter  

SciTech Connect

A power generation system for converting the motion of waves on a body of water such as a lake or sea to drive pumps, electrical generators or the like. A weighted float rides on the waves. A cable and pulley arrangement changes the direction, travel and force of the wave energy action imparted on the float and drives a hydraulic circuit. The hydraulic circuit includes an accumulator for temporary energy storage and release to assist in maintaining constant flow and pressure of hydraulic fluid to one or more hydraulic motors during each wave cycle. The hydraulic motor drives a load such as an electric generator. An automatically actuated device adjusts for high and low tides.

Taylor, R.N.

1984-02-28

14

Performance Assessment of the Wave Dragon Wave Energy Converter  

E-print Network

Performance Assessment of the Wave Dragon Wave Energy Converter Based on the EquiMar Methodology S of the wave energy sector, device developers are called to provide reliable estimates on power performance. Indications about power performance and production of the device at the target locations, as well

Hansen, René Rydhof

15

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

SciTech Connect

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

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

2013-12-07

16

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

17

Power recycling for an interferometric gravitational wave  

E-print Network

THESIS Power recycling for an interferometric gravitational wave detector Masaki Ando Department Gravitational Waves 9 2.1 Wave solutions of the Einstein equation . . . . . . . . . . . . . . . 10 2 . . . . . . . . . . . . . . . . . . . . . . . 10 2.1.3 Gravitational wave . . . . . . . . . . . . . . . . . . . . . . 12 2.1.4 Effect

Ejiri, Shinji

18

Wave power absorption: Experiments in open sea and simulation  

Microsoft Academic Search

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

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

2007-01-01

19

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

E-print Network

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

Li, Bin

2012-11-29

20

Tsunami wave energy  

E-print Network

In the vast literature on tsunami research, few articles have been devoted to energy issues. A theoretical investigation on the energy of waves generated by bottom motion is performed here. We start with the full incompressible Euler equations in the presence of a free surface and derive both dispersive and non-dispersive shallow-water equations with an energy equation. It is shown that dispersive effects only appear at higher order in the energy budget. Then we solve the Cauchy-Poisson problem of tsunami generation for the linearized water wave equations. Exchanges between potential and kinetic energies are clearly revealed.

Dutykh, Denys

2008-01-01

21

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

NSDL National Science Digital Library

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

22

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

23

Overview of Ocean Wave and Tidal Energy Lingchuan Mei  

E-print Network

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

Lavaei, Javad

24

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

25

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

26

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

PubMed Central

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

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

2014-01-01

27

Formation of power-law energy spectra in space plasmas by stochastic acceleration due to whistler-mode waves  

NASA Astrophysics Data System (ADS)

A non-relativistic Fokker-Planck equation for the electron distribution function is formulated incorporating the effects of stochastic acceleration by whistler-mode waves and Coulomb collisions. The stationary solution f to the equation, subject to a zero-flux boundary condition, is found to be a generalized Lorentzian (or kappa) distribution, which satisfies f ? ?2(?+1) for large velocity ? where ? is the spectral index. The parameter ? depends strongly on the relative wave intensity R. Taking into account the critical energy required for resonance of electrons with whistlers, we calculate a range of values of R for each of a number of different space plasmas for which kappa distributions can be expected to be formed. This study is one of the first in the literature to provide a theoretical justification for the formation of generalized Lorentzian (or kappa) particle distribution functions in space plasmas.

Ma, Chun-yu; Summers, Danny

28

A modified Wells turbine for wave energy conversion  

Microsoft Academic Search

The method of wave energy conversion utilises an oscillating water column (OWC). The OWC converts wave energy into low-pressure pneumatic energy in the form of bi-directional airflow. Wells turbine with its zero blade pitch setting has been used to convert this pneumatic power into uni-directional mechanical shaft power. Measurements in OWC based wave energy plants in India and Japan show

T. Setoguchi; S. Santhakumar; M. Takao; T. H. Kim; K. Kaneko

2003-01-01

29

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

PubMed

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

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

2003-01-17

30

Second Proof Work, Power, and Energy  

E-print Network

and minimal impact on the environment. energy conversion A process of transformation of one form of energy) energy sources, such as solar energy, wind, water flows, ocean and tidal waves, and biomassSecond Proof Work, Power, and Energy M. KOSTIC Northern Illinois University DeKalb, Illinois

Kostic, Milivoje M.

31

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. PMID:16593813

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

1987-01-01

32

California Small Hydropower and Ocean Wave Energy  

E-print Network

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

33

Ocean wave energy converter  

SciTech Connect

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 within the tube receptacles approximately forming trimetric edge elements of a right conical frustum; a separable buoyancy device affixed to the upper portions of the tubular members above the lower structural support means, the buoyancy device having upper and lower surfaces and an enclosed space therein; an annulated receptacle plate affixed to the upper surface of the buoyancy device; truncated right circular cylinders connected to the annulated receptacle plate extending outwardly in coaxial alignment with respective tubular members; articulated brackets connected to the annulated receptacle plate in radial extension; upper structural support means connected to the articulated brackets in radial extension for connection to other receptacle plate articulated brackets of a module array; and dual rolling contact support means comprising open linear slide bearings operatively positioned within the tube upper portions and the truncated cylinders.

Ames, P.F.

1987-06-09

34

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

35

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

36

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

E-print Network

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

Victoria, University of

37

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

38

Gravitational wave generation in power-law inflationary models  

E-print Network

We investigate the generation of gravitational waves in power-law inflationary models. The energy spectrum of the gravitational waves is calculated using the method of continuous Bogoliubov coefficients. We show that, by looking at the interval of frequencies between 10^(-5) and 10^5 Hz and also at the GHz range, important information can be obtained, both about the inflationary period itself and about the thermalization regime between the end of inflation and the beginning of the radiation-dominated era. We thus deem the development of gravitational wave detectors, covering the MHz/GHz range of frequencies, to be an important task for the future.

Paulo M. Sá; Alfredo B. Henriques

2008-04-21

39

Protective, Modular Wave Power Generation System  

SciTech Connect

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

Vvedensky, Jane M.; Park, Robert Y.

2012-11-27

40

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

E-print Network

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

Morrison, Philip J.,

41

Erratum: ``Formation of Power-law Energy Spectra in Space Plasmas by Stochastic Acceleration due to Whistler-Mode Waves''  

Microsoft Academic Search

A non-relativistic Fokker-Planck equation for the electron distribution function is formulated incorporating the effects of stochastic acceleration by whistler-mode waves and Coulomb collisions. The stationary solution f to the equation, subject to a zero-flux boundary condition, is found to be a generalized Lorentzian (or kappa) distribution, which satisfies f~v-2(kappa+1) for large velocity v, where kappa is the spectral index. The

Chun-yu Ma; Danny Summers

1999-01-01

42

Formation of power-law energy spectra in space plasmas by stochastic acceleration due to whistler-mode waves  

Microsoft Academic Search

A non-relativistic Fokker-Planck equation for the electron distribution function is formulated incorporating the effects of stochastic acceleration by whistler-mode waves and Coulomb collisions. The stationary solution f to the equation, subject to a zero-flux boundary condition, is found to be a generalized Lorentzian (or kappa) distribution, which satisfies f~v2(kappa+1) for large velocity v, where kappa is the spectral index. The

Chun-Yu Ma; Danny Summers

1998-01-01

43

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

44

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

45

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

46

Wave and tide powered generation apparatus  

Microsoft Academic Search

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

Suggs

1985-01-01

47

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

48

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

49

Quantifying the Benefits of Combining Offshore Wind and Wave Energy  

NASA Astrophysics Data System (ADS)

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

Stoutenburg, E.; Jacobson, M. Z.

2009-12-01

50

Energy and hegemonic power  

NASA Astrophysics Data System (ADS)

Current theories of hegemony have, for the most part, ignored energy as a factor. It is argued here, however, that there are three reasons to expect energy to be a factor in the rise of nations to hegemonic power. First, societies require flow-throughs of energy, material, and information in order to maintain themselves, grow, and develop. Second, the types of energy systems used by a society set somewhat predictable limits on what humans can do and on how they will be organized. And third, since different energy sources and their associated technologies exhibit different capabilities and limitations, advantages may be conferred on one society over another based on the energy sources used by those societies. Case studies of the economic, military, and energy systems of the four nations that have achieved hegemony---Portugal, the Netherlands, the United Kingdom, and the United States---found that changes in energy systems were a significant factor in each instance of hegemony. Also examined was the premise that the rise and decline of hegemonic powers may reflect the movement away from, and subsequent return to, a condition of steady-state---where a society's energy systems, and those parts of the society that respond to changes in energy factors, change very slowly over time. It was postulated that an extended period of stable energy conditions in conjunction with the diffusion of technology would erode any energy-based differences in power among nations. While, on the other hand, the movement away from a condition of steady-state brought on by changes in a society's energy systems might provide that society with enough advantages that it could seek hegemony. Evidence for an association between the movement from one steady-state to another and the rise and decline of hegemony was found in only two of the four cases.

Hale, Cameron Edward

51

Wave refraction and wave energy on Cayo Arenas  

E-print Network

WAVE REFRACTION AND WAVE ENERGY ON CAYO ARENAS A Thesis By Donald E. Welsh Submitted to the Graduate School of the Agricultural and Mechanical College of Texas in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE... January 1962 Major Subject: Physical Oceanography WAVE REFRACTION AND WAVE ENERGY ON CAYO ARENAS A Thesis Donald E. Walsh Approved as to style and content by: Chairman of the Committee ead of Department ' / January 1962 ACKNOWLEDGMENTS...

Walsh, Donald Eugene

2012-06-07

52

Ocean wave energy converting vessel  

SciTech Connect

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

Boyce, P.F.

1986-08-26

53

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

E-print Network

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

54

Wave power absorption characteristics of a rocking body  

NASA Astrophysics Data System (ADS)

The power characteristics and efficiency of a wave power absorber consisting of a rocking body and a hydro-static power conversion mechanism are examined. The efficiency of the wave power absorber depends both on the shape of the front section of the body and on the local characteristics of the power taking-off mechanism. It is confirmed that the rocking body absorbs wave power with high efficiency when it is oscillated at resonant frequency and the load damping torque is controlled to be equal to half the wave exciting torque.

Tanaka, H.; Saito-O., M.

1981-02-01

55

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

56

Vertically Driven Waves: Energy Transfer Between Gravity Waves Revisited  

E-print Network

We investigate the energy transfer from large waves to small ones through vertical acceleration and demonstrate that this is a much larger effect than that of the potential energy changes of the small waves moving over the larger ones. Rates of exponential growth for this process are given and limits on the stable size of small waves in the horizontal accelerations from the larger ones are derived. We discuss the possibility of this being a manifestation of the Benjamin-Feir instability.

Chafin, Clifford

2014-01-01

57

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

PubMed Central

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

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

2012-01-01

58

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

59

Millimeter-Wave Power-Combining with Radiating Oscillator Arrays.  

NASA Astrophysics Data System (ADS)

The next generation of communications and radar systems will soon begin to exploit the millimeter-wave portion of the electromagnetic spectrum. Such systems will require a high-power source of millimeter-wave energy, ideally small, lightweight, highly efficient, and failure -proof over a span of decades. Circuits using semiconductor devices have proved useful for this purpose at lower frequencies, but unfortunately the power generating capacity of solid -state devices diminishes quickly as frequencies approach 100 GHz. This has forced designers to use bulky, inefficient, and unreliable (but high-power) vacuum-tube sources. Combining the power produced by a large number of individual solid-state devices has been suggested as a means of overcoming the inherent limitations of millimeter -wave devices. In order to compete with vacuum-tube sources, power-combiners would require up to 1000 devices, presenting a difficult engineering challenge. This thesis introduces one possible solution to this problem. The proposed concept uses arrays of millimeter-wave oscillators, where each oscillator contains one or more active devices in a planar radiating structure. The oscillators are weakly coupled to synchronize frequency and phase relationships, and the power produced by each oscillator is radiatively combined in free-space, which gives rise to very high combining efficiencies. The array concept has been demonstrated at microwave frequencies using both Gunn and MESFET devices in a 4 x 4 patch antenna configuration. The Gunn array produced 22 Watts Equivalent Radiated Power (ERP), and the MESFET array produced 10 Watts ERP. A new theory has been developed which describes the coupled-oscillator dynamics, and has been shown to accurately predict experimentally observed effects. In addition to strict CW power-combining, a new mode of operation has been discovered which enables the same arrays to generate high-power pulses of energy. This new effect involves a "mode-locking" approach, similar to a commonly used technique in lasers, and has the inherent property of beam-scanning. These effects have been observed experimentally, and can also be explained using the coupled -oscillator theory.

York, Robert Armstrong

60

24 DTU International Energy Report 2013 Stochastic power generation  

E-print Network

that their power output can be curtailed if necessary. Renewable energy sources such as wind, solar, wave and tidal24 DTU International Energy Report 2013 Stochastic power generation Introduction Our path towards intheformofheatandelectricity.ByJune2012,cumula- tive installed wind power capacity worldwide had reached 254

Paris-Sud XI, Université de

61

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

NASA Astrophysics Data System (ADS)

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

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

62

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

63

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

64

Correction to “Formation of power-law energy spectra in space plasmas by stochastic acceleration due to whistler-mode waves”  

NASA Astrophysics Data System (ADS)

A non-relativistic Fokker-Planck equation for the electron distribution function is formulated incorporating the effects of stochastic acceleration by whistler-mode waves and Coulomb collisions. The stationary solution f to the equation, subject to a zero-flux boundary condition, is found to be a generalized Lorentzian (or kappa) distribution, which satisfies f ? ?-2(?+1) for large velocity ?, where ? is the spectral index. The parameter ? depends strongly on the relative wave intensity R. Taking into account the critical energy required for resonance of electrons with whistlers, we calculate a range of values of R for each of a number of different space plasmas for which kappa distributions can be expected to be formed. This study is one of the first in the literature to provide a theoretical justification for the formation of generalized Lorentzian (or kappa) particle distribution functions in space plasmas.

Ma, Chun-yu; Summers, Danny

65

Interacting ocean waves explain powerful seafloor canyon flows  

NASA Astrophysics Data System (ADS)

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

Schultz, Colin

2012-02-01

66

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

67

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

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

68

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

SciTech Connect

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

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

1996-12-31

69

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

SciTech Connect

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

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

1997-08-01

70

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

SciTech Connect

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

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

1994-12-31

71

High Performance Circuits for Power Management and Millimeter Wave Applications  

E-print Network

HIGH PERFORMANCE CIRCUITS FOR POWER MANAGEMENT AND MILLIMETER WAVE APPLICATIONS A Dissertation by AHMED MOHSEN AHMED AMER Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment... of the requirements for the degree of DOCTOR OF PHILOSOPHY May 2012 Major Subject: Electrical Engineering High Performance Circuits for Power Management and Millimeter Wave Applications Copyright 2012 Ahmed Mohsen...

Amer, Ahmed 1979-

2012-01-23

72

Pump enhanced monochromatic terahertz-wave parametric oscillator toward megawatt peak power.  

PubMed

Pump enhanced optical parametric oscillation under a cavity phase matching configuration is an effective way to obtain monochromatic THz waves with high pulse energy. Numerical simulations are conducted for THz wave generations using a GaP sheet cavity. By optimizing the optical pulse duration and cavity configuration, the estimated peak power of THz waves is 4 MW at 3 THz, which corresponds to the photon conversion efficiency of ??0.81. Our proposed scheme can generate a THz wave with high pulse energy, which is suitable for the nonlinear optical effects in the THz frequency region. PMID:25360958

Saito, Kyosuke; Tanabe, Tadao; Oyama, Yutaka

2014-10-01

73

Wave energy devices with compressible volumes  

PubMed Central

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

Kurniawan, Adi; Greaves, Deborah; Chaplin, John

2014-01-01

74

Standing wave tube electro active polymer wave energy converter  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

75

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

76

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

77

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

78

What can wave energy learn from offshore oil and gas?  

PubMed

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

Jefferys, E R

2012-01-28

79

The Force of a Tsunami on a Wave Energy Converter  

E-print Network

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

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

2012-01-01

80

PIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY  

E-print Network

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

Ervin, Elizabeth K.

81

Laser power and energy measurements  

Microsoft Academic Search

Any laser system comprises a coherent source of radiation and a detector which responds to the temporal and\\/or spatial intensity variation of the radiation. Laser source and detector characterization necessary for design of laser systems is reviewed based on the concepts of radiant power and radiant energy to characterize instantaneous or average radiation. Measurement of total energy and average power

H. S. Boyne

1975-01-01

82

78 FR 40132 - Wave Energy Converter Prize Administration Webinar  

Federal Register 2010, 2011, 2012, 2013, 2014

...entities with experience in testing wave energy converters in tank test facilities...administering technical competitions. Wave Energy Converter Prize Background...potential for success in the actual open-ocean wave energy harvesting environment....

2013-07-03

83

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

E-print Network

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

84

Oblique sounding of the ionosphere by powerful wave beams  

NASA Astrophysics Data System (ADS)

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

Molotkov, I. A.; Atamaniuk, B.

2011-04-01

85

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

86

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

87

Understanding Wave Motion and Power Loss  

NSDL National Science Digital Library

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

88

The electromagnetic spectrum : waves of energy  

NSDL National Science Digital Library

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

Coulson, Tracy; Kennedy, Karen

2002-01-01

89

A resonant point absorber of ocean-wave power  

Microsoft Academic Search

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

K. Budar; J. Falnes

1975-01-01

90

Analysis of shock-wave-actuated ferroelectric power supplies  

Microsoft Academic Search

Electrical pulses with peak powers of a few hundred kilowatts lasting for several microseconds can be obtained by depoling ferroelectric materials with shock waves. This charge release process is most efficient when the shock amplitude is sufficient to induce a transformation to a non-ferroelectric phase. We will consider the cases in which planar shock waves propagate with a constant velocity

P. C. Lysne; C. M. Percival

1976-01-01

91

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

92

Bridge-Chopper Inverter for 400 CPS Sine Wave Power  

Microsoft Academic Search

A new d-c to a-c inverter has been developed. Sine wave power at 400 cps is provided without a 400 cps filter or 400 cps transformer. A bridge type chopper circuit, chopping at 50 KC, is used to provide the a-c power. The bridge-chopper inverter is approximately 1\\/3 the size and weight of present sine wave inverters used in most

Ray E. Morgan

1964-01-01

93

Spatial power combining for millimeter-wave solid state amplifiers  

Microsoft Academic Search

A novel method for obtaining high power amplification at millimeter-wave frequencies using spatial power combining is being developed. The method uses orthogonally polarized fields to isolate the input and output waves of a two-dimensional array of solid-state amplifiers. To demonstrate this technique, a proof-of-concept model was developed using a 69-element array of orthogonally polarized elements at 17 GHz. The proposed

J. A. Benet; A. R. Perkons; S. H. Wong; A. Zaman

1993-01-01

94

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

95

The Power of Energy  

NSDL National Science Digital Library

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

Diana Congden

2012-06-14

96

Water Power for a Clean Energy Future (Fact Sheet)  

SciTech Connect

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

Not Available

2010-07-01

97

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

98

The Power of Energy Storage  

E-print Network

. As California seeks to expand solar and wind power, storage of that energy for use at any time, day or night pumping water uphill overnight, when demand is low and electricity is cheap, and then releasing

Sadoulet, Elisabeth

99

Energy, A Crisis in Power.  

ERIC Educational Resources Information Center

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

Holdren, John; Herrera, Philip

100

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

ERIC Educational Resources Information Center

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

Harris, Fank

2014-01-01

101

Wave energy in Europe: current status and perspectives  

Microsoft Academic Search

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

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

2002-01-01

102

Multi-electrodes in SAW with square wave ac power  

SciTech Connect

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

Bunker, T.A.

1982-07-01

103

Soft Capacitors for Wave Energy Harvesting  

E-print Network

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

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

2011-04-21

104

CHARACTERIZING DANGEROUS WAVES FOR OCEAN WAVE ENERGY CONVERTER SURVIVABILITY Justin Hovland  

E-print Network

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

Haller, Merrick

105

Analysis of the power capacity of overmoded slow wave structures  

NASA Astrophysics Data System (ADS)

As the generated wavelength shortens, overmoded slow wave structures (SWSs) with large diameters are employed in O-type Cerenkov high power microwave (HPM) generators to achieve high power capacity. However, reported experimental results suggest that overmoded slow wave HPM generators working at millimeter wavelength output much lower power than those working at X-band do, despite the fact that the value of D/? (here, D is the average diameter of SWSs and ? is the generated wavelength) of the former is much larger than that of the latter. In order to understand this, the characteristics of the power capacity of the TM0n modes in overmoded SWSs are numerically investigated. Our analysis reveals the following facts. First, the power capacity of higher order TM0n modes is apparently larger than that of TM01 mode. This is quite different from the conclusion got in the foregone report, in which the power capacity of overmoded SWSs is estimated by that of smooth cylindrical waveguides. Second, the rate at which the power capacity of TM01 mode in overmoded SWSs grows with diameter does not slow down as the TM01 field transforms from "volume wave" to "surface wave." Third, once the diameter of overmoded SWSs and the beam voltage are fixed, the power capacity of TM01 wave drops as periodic length L shortens and the generated frequency rises, although the value of D/? increases significantly. Therefore, it is necessary to investigate the capability of annular electron beam to interact efficiently with higher order TM0n modes in overmoded SWSs if we want to improve the power capacity of overmoded O-type Cerenkov HPM generators working at high frequency.

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

2013-07-01

106

Precise Calibration of Plane-Wave Microwave Power Density Using Power Equation Techniques  

Microsoft Academic Search

A power-density calibration methodology utilizing an anechoic chamber, high-power transmitter, and truncated pyramidal horn antenna is described, Plane-wave power density is accurately computed in the far field of the antenna, based upon precise measurements of antenna gain, absolute transmitted power, and multipath reflections. The application of power equation techniques enables direct precise measurements of system mismatches and the accurate transfer

HOWARD I. BASSEN; WILLIAM A. HERMAN

1977-01-01

107

Power capacity of mixed modes in overmoded slow wave structures  

NASA Astrophysics Data System (ADS)

In slow wave structures (SWSs) of overmoded relativistic backward wave oscillators (RBWOs), multiple symmetric transversal magnetic (TM0n) modes frequently present coexistence. Since the power capacity of higher order TM0n mode is apparently higher than that of TM01 mode, the introduction of higher order TM0n mode in SWSs seems to be beneficial for improving the power capacity of overmoded RBWOs. However, our analysis indicates that the power capacity of TM0n mixed modes is lower than that of pure TM01 mode, in exception of the condition that the power proportions of higher order TM0n modes are sufficiently high, or the phases of TM0n modes in finitely long SWSs are cautiously manipulated. In addition, we realize that higher mode purity brings about higher power capacity in SWSs.

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

2014-07-01

108

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

Microsoft Academic Search

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

H. Lund

2006-01-01

109

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

E-print Network

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

Crozier, Richard Carson

2014-06-30

110

Two-stream instability, wave energy, and the energy principle  

NASA Astrophysics Data System (ADS)

A generalized Poynting theorem for a system of uniform electron beams is obtained. Two examples of the two-stream instability with beams of equal density are used to discuss the relation between negative wave energy and negative potential energy, which arises in the energy principle of ideal magnetohydrodynamics. In the first example, v10>v20, while in the second example, v20=-v10, where v10,20 are the equilibrium beam velocities. Both cases can be interpreted in terms of the energy density arising from the generalized Poynting theorem. The first instability is due to the coupling of negative and positive energy waves at a frequency k (v10+v20)/2. The second instability is due to the coupling of the same two perturbations, but at zero frequency. In this case, there is no oscillatory (wave) energy, but the beam electrons still make a negative contribution to the total energy.

Lashmore-Davies, C. N.

2007-09-01

111

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

SciTech Connect

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

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

1994-12-31

112

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

113

The Future Potential of Wave Power in the US  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

114

IEEE POWER ENGINEERING SOCIETY ENERGY DEVELOPMENT AND POWER GENERATION COMMITTEE  

E-print Network

IEEE POWER ENGINEERING SOCIETY ENERGY DEVELOPMENT AND POWER GENERATION COMMITTEE Latin America Sponsored by: International Practices for Energy Development and Power Generation Chairs: Luiz Barroso, PSR utilities (Discos) that buy power supply from generators in both the long term and sport markets. For more

Catholic University of Chile (Universidad Católica de Chile)

115

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

116

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

117

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

PubMed

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

Wong, Alex M H; Eleftheriades, George V

2015-01-01

118

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

PubMed Central

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

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

2015-01-01

119

Correction to ``Formation of power-law energy spectra in space plasmas by stochastic acceleration due to whistler-mode waves''  

Microsoft Academic Search

A non-relativistic Fokker-Planck equation for the electron distribution function is formulated incorporating the effects of stochastic acceleration by whistler-mode waves and Coulomb collisions. The stationary solution f to the equation, subject to a zero-flux boundary condition, is found to be a generalized Lorentzian (or kappa) distribution, which satisfies f~v-2(kappa+1) for large velocity v, where kappa is the spectral index. The

Chun-yu Ma; Danny Summers

1999-01-01

120

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

E-print Network

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

Spaulding, Jonathon David

2010-01-01

121

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

122

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

123

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

Microsoft Academic Search

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

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

2011-01-01

124

High-power continuous-wave quantum cascade lasers  

Microsoft Academic Search

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

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

1998-01-01

125

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

NASA Astrophysics Data System (ADS)

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

Walker, A. D. M.

2014-12-01

126

Liquefaction Opportunity Mapping via Seismic Wave Energy  

Microsoft Academic Search

An empirical, energy-based methodology for liquefaction hazard assessment and microzonation mapping is presented. The approach is probabilistic, considers the uncertainty in the liquefaction criterion, and is applicable to most earthquake-induced liquefaction analyses. The examples illustrated are for water-saturated sands at level ground. The energy of ground shaking is estimated from the Fourier amplitude spectra of the incident waves. The susceptible

M. I. Todorovska; M. D. Trifunac

1999-01-01

127

A New High Efficiency Power Amplifier for Modulated Waves  

Microsoft Academic Search

This paper introduces a new form of linear power amplifier for modulated radio-frequency waves. Plate circuit efficiencies of sixty to sixty-five per cent independent of modulation are obtained by means of the combined action of varying load distribution among the tubes and varying circuit impedance over the modulation cycle. The theory of operation is developed and detailed observations on the

W. H. Doherty

1936-01-01

128

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

129

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

SciTech Connect

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

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

2014-09-01

130

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

131

ENergy and Power Evaluation Program  

SciTech Connect

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

NONE

1996-11-01

132

OCEAN WAVES, MECHANICAL IMPULSES AND ELECTRICAL ENERGY: CONCEPT OF A SIMPLE CONVERSION PROCESS  

Microsoft Academic Search

Estimates suggest that a meter of a wave front carries ~ 100 kW of power. A significant amount of renewable energy is hence dissipated across the time scale of minutes as surface gravity waves dissipate on any beach. Given that the majority of the world population lives near the ocean, it makes sense to explore new technologies associated with the

Surajit Sen; Adam Sokolow; Robert Paul Simion; Diankang Sun; Robert L. Doney; Masami Nakagawa; Juan H. Agui

2007-01-01

133

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

134

On the design of a prototype model of the floating wave power device ``Mighty Whale``  

SciTech Connect

The Mighty Whale is a floating wave power device to convert the wave energy to other convenient energy for the conservation of the sea, and to create the calm sea area such as a floating breakwater. JAMSTEC (Japan Marine Science and Technology Center) has been promoting the R and D on this Mighty Whale since 1986. Already, the authors have finished fundamental development by theoretical, numerical and experimental study on the basic Mighty Whale. By 1996, they will finish designing the prototype model of the Mighty Whale, will start to construct it, and will carry out the open sea test between 1998 and 1999 at the coastal sea of Japan. The dimensions of the Mighty Whale are 50m in length, 30m in breadth and it has 3 air chambers, 3 units of the air turbines and generators of 50 kW rated power. It will be moored by mooring chains and anchors at the site of about 35m water depth. The mechanism to absorb the wave energy is of the OWC (Oscillating Water Column) type with the Wells Turbine. Its efficiency to absorb the wave energy is about 40--50% on average in regular waves, and it can make in the lee zone the height of incident waves about one half under 8 sec of the significant wave period. Because of such behavior, and from the view point of sustainable development at the coastal zone, the authors recognize the Mighty Whale can be a convenient and beneficial structure for the coastal development. In this paper, they introduce this design, and discuss the utilization of the Mighty Whale for the coastal development.

Hotta, H.; Washio, Y.; Yokozawa, H.; Pizer, D.J. [JAMSTEC, Yokosuka (Japan)

1996-12-31

135

High power single frequency solid state master oscillator power amplifier for gravitational wave detection.  

PubMed

High power single frequency, single mode, linearly polarized laser output at the 1 ?m regime is in demand for the interferometric gravitational wave detectors (GWDs). A robust single frequency solid state master oscillator power amplifier (MOPA) is a promising candidate for such applications. We present a single frequency solid state multistage MOPA system delivering 177 W of linearly polarized output power at 1 ?m with 83.5% TEM(00) mode content. PMID:22825159

Basu, Chandrajit; Wessels, Peter; Neumann, Jörg; Kracht, Dietmar

2012-07-15

136

E2I EPRI Assessment Offshore Wave Energy Conversion Devices  

E-print Network

E2I EPRI Assessment Offshore Wave Energy Conversion Devices Report: E2I EPRI WP ­ 004 ­ US ­ Rev 1 #12;E2I EPRI Assessment - Offshore Wave Energy Conversion Devices Table of Contents Introduction Assessment - Offshore Wave Energy Conversion Devices Introduction E2I EPRI is leading a U.S. nationwide

137

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

138

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

SciTech Connect

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

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

2015-01-01

139

A powerful reflector in relativistic backward wave oscillator  

SciTech Connect

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

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

2014-09-15

140

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

141

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

142

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

143

Voltage, energy and power in electric circuits  

E-print Network

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

Berzins, M.

144

A low-power wave union TDC implemented in FPGA  

SciTech Connect

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

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

2011-10-01

145

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

146

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

SciTech Connect

This project is an industry-led partnership between Columbia Power Technologies and Oregon State University that will perform benchmark laboratory experiments and numerical modeling of the near-field and far-field impacts of wave scattering from an array of wave energy devices. These benchmark experimental observations will help to fill a gaping hole in our present knowledge of the near-field effects of multiple, floating wave energy converters and are a critical requirement for estimating the potential far-field environmental effects of wave energy arrays. The experiments will be performed at the Hinsdale Wave Research Laboratory (Oregon State University) and will utilize an array of newly developed Buoys������� that are realistic, lab-scale floating power converters. The array of Buoys will be subjected to realistic, directional wave forcing (1:33 scale) that will approximate the expected conditions (waves and water depths) to be found off the Central Oregon Coast. Experimental observations will include comprehensive in-situ wave and current measurements as well as a suite of novel optical measurements. These new optical capabilities will include imaging of the 3D wave scattering using a binocular stereo camera system, as well as 3D device motion tracking using a newly acquired LED system. These observing systems will capture the 3D motion history of individual Buoys as well as resolve the 3D scattered wave field; thus resolving the constructive and destructive wave interference patterns produced by the array at high resolution. These data combined with the device motion tracking will provide necessary information for array design in order to balance array performance with the mitigation of far-field impacts. As a benchmark data set, these data will be an important resource for testing of models for wave/buoy interactions, buoy performance, and far-field effects on wave and current patterns due to the presence of arrays. Under the proposed project we will initiate high-resolution (fine scale, very near-field) fluid/structure interaction simulations of buoy motions, as well as array-scale, phase-resolving wave scattering simulations. These modeling efforts will utilize state-of-the-art research quality models, which have not yet been brought to bear on this complex problem of large array wave/structure interaction problem.

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

2013-01-26

147

Magnetospheric ULF Wave Power as a Function of Solar Wind Variations  

NASA Astrophysics Data System (ADS)

Magnetospheric ULF waves at Pc-5 (mHz) frequencies may have profound effects on relativistic electron fluxes in the outer radiation belts by driving radial diffusion, a process which may either deplete the belts of electrons by allowing electrons to drift outward through the stable trapping boundary, or increasing the overall energy content of the belts through inward radial diffusion and energization of energetic electrons. The energy for most global-scale Pc-5 activity results from the driving action of the solar wind, either through shear interactions at the magnetopause flanks, or directly through pressure or IMF variations embedded in the background solar wind. However, the relationship between ULF power at a given point in the magnetosphere and the driving power of the solar wind is not simple: as a wave propagates through the magnetosphere, partial reflections from Alfven gradients, magnetospheric field line resonances, and global cavity modes may all act to either enhance or suppress wave power at a given frequency and location in space. In this effort we use global MHD simulations of the magnetosphere/solar wind interaction to probe the mapping function of fluctuations in the solar wind into Pc-5 ULF power in the inner magnetosphere and radiation belts. Broadband variations in solarwind conditions are imposed, and the resulting ULF activity in the magnetosphere characterized as a function of frequency and location. This ULF activity may then be used to characterize radial transport rates in the radiation belts in terms of relevant diffusion coefficients. By comparing the ULF power distribution in the magnetosphere during events driven by observed solar wind conditions to those characterized by our broadband mapping, we investigate the feasibility of empirically modeling magnetospheric ULF wave activity as it relates to ULF power in the solar wind.

Elkington, S. R.; Claudepierre, S. G.; Wiltberger, M. J.

2009-12-01

148

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

NASA Astrophysics Data System (ADS)

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

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

2010-06-01

149

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

150

Device for extracting energy from waves  

SciTech Connect

A device is described for extracting energy from sea waves by the motion of a submerged cylinder held normal to the direction of motion of the waves by tie members at each end of the cylinder. The tie members at their other respective ends are moored to the sea bed. Changes in the load on the tie members are arranged to turn in one direction a drum drivably connected to a vane pump. A spring, or a counterweight acting on a cam-shaped pulley, is arranged to apply a biasing load to the drum in the other direction so as to produce an oscillatory movement of the drum from changes in load on the tie members and drive the pump. A hydraulic motor connected to an electric generator is driven by the pump. The drum may be situated at the moorings on the sea bed, or at the cylinder.

Davis, J.P.; Evans, D.V.; Shaw, T.L.

1980-06-24

151

Internal energy relaxation in shock wave structure  

SciTech Connect

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

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

2013-12-15

152

Device for converting sea wave energy into electrical energy  

SciTech Connect

A device for converting sea wave energy into electrical energy comprises a floating platform carrying a pulley which is connected through a free-wheel coupling and a speed multiplier to a drive shaft of an electrical generator, on which a flywheel is mounted. An anchor cable passes over the pulley and suspends at its free end an immersed counterweight so that vertical motion of the platform in the sea causes rotation of the pulley and drives the generator continuously.

Quilico, C.A.; Troya, P.M.

1980-12-30

153

Enhanced RF extraction efficiency in high power traveling wave tubes  

NASA Astrophysics Data System (ADS)

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

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

1996-11-01

154

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

155

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

156

Global energy conversion rate from geostrophic flows into internal lee waves in the deep ocean  

NASA Astrophysics Data System (ADS)

A global estimate of the energy conversion rate from geostrophic flows into internal lee waves in the ocean is presented. The estimate is based on a linear theory applied to bottom topography at O(1-10) km scales obtained from single beam echo soundings, to bottom stratification estimated from climatology, and to bottom velocity obtained from a global ocean model. The total energy flux into internal lee waves is estimated to be 0.2 TW which is 20% of the global wind power input into the ocean. The geographical distribution of the energy flux is largest in the Southern Ocean which accounts for half of the total energy flux. The results suggest that the generation of internal lee waves at rough topography is a significant energy sink for the geostrophic flows as well as an important energy source for internal waves and the associated turbulent mixing in the deep ocean.

Nikurashin, Maxim; Ferrari, Raffaele

2011-04-01

157

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

E-print Network

as the European Ocean Energy Association, which has been formed by all stakeholders in ocean energy (both within.eu-oea.com/). The International Energy Agency In 2001, the International Energy Agency (IEA) formed an Implementing Agreement2007 Survey of Energy Resources World Energy Council 2007 Wave Energy 550 COUNTRY NOTES

158

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

159

Mapping and Assessment of the United States Ocean Wave Energy Resource  

SciTech Connect

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

Paul T. Jacobson; George Hagerman; George Scott

2011-12-01

160

Study on the Temperature Limitation of the Injecting Power to a Pyramidal EM-Wave Absorber  

Microsoft Academic Search

In this paper, first the temperature distribution of the pyramidal EM-wave absorber is calculated in the coupled method. Next, the injected power to the EM-wave absorber is changed to estimate the maximum power density that the EM-wave absorber can resist. As a result, the limitation of the injecting power density to a pyramidal EM-wave absorber is achievable.

Tetsuhiro Sasagawa; Shinya Watanabe; Osamu Hashimoto; Toshifumi Saito; Hiroshi Kurihara

2009-01-01

161

An atlas of the wave-energy resource in Europe  

SciTech Connect

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

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

1996-11-01

162

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

163

On the relationship between magnetostatic wave energy and dispersion characteristics in ferrite structures  

NASA Astrophysics Data System (ADS)

The energy and dispersion characteristics of a dipole spin wave in a ferrite-dielectric-metal structure are calculated. An analysis of spin wave dispersion characteristics with extreme points demonstrates how fundamental relationships among the propagation constant, phase and group velocities, Poynting vector, and power flux manifest themselves when the wavenumber changes near these points. A comparison of magnetostatic approximation results with calculations using Maxwell's equations shows the inadequacy of the magnetostatic approximation formulas currently used for calculating the Poynting vector and power flux of dipole spin waves. A correct alternative is proposed.

Vashkovsky, Anatolii V.; Lock, Edwin H.

2011-03-01

164

Power electronics in wind energy conversion systems  

Microsoft Academic Search

This paper presents a brief review of the power electronics techniques used in wind energy conversion systems. Utilization of power electronics converters enables conversion of the generated power from any form to another and thus control the operation quality and obtain capture optimization. Attention is paid to power converters selection and design to satisfy good matching between generator type and

FAEKA M. H. KHATER

1996-01-01

165

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

166

Experimental determination of radiated internal wave power without pressure field data  

NASA Astrophysics Data System (ADS)

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

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

2014-04-01

167

Experimental determination of radiated internal wave power without pressure field data  

SciTech Connect

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

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

2014-04-15

168

Power and Energy Management for Server Systems  

Microsoft Academic Search

Power and energy consumption are key concerns for Internet data centers. These centers house hun- dreds, sometimes thousands, of servers and supporting cooling infrastructures. Research on power and energy management for servers can ease data center installation, reduce costs, and protect the environ- ment. Given these benefits, researchers have made important strides in conserving energy in servers. Inspired by this

Ricardo Bianchini; Ramakrishnan Rajamony

2004-01-01

169

Design of stabilization system for medium wave infrared laser power  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

170

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

E-print Network

Electromagnetic Wave Power Observed Near the Moon during Terrestrial Bow Shock Crossings and Its waves can create source signals. The Moon encounters a wide variety plasma frequencies at each crossing observations of EM wave power near the Moon during terrestrial bow shock crossings, speculate on the origin

Fillingim, Matthew

171

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

E-print Network

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

Texas at Austin. University of

172

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

173

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

174

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

Microsoft Academic Search

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

Herbert C. Carlson

1993-01-01

175

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

176

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

SciTech Connect

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

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

2014-10-01

177

Acceleration of low energy charged particles by gravitational waves  

E-print Network

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

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

2005-12-07

178

The role of the electron energy distribution in ionization waves  

Microsoft Academic Search

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

S W Rayment

1974-01-01

179

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

2010-04-01

180

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

E-print Network

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

Victoria, University of

181

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

182

Novel two-stage piezoelectric-based ocean wave energy harvesters for moored or unmoored buoys  

NASA Astrophysics Data System (ADS)

Harvesting mechanical energy from ocean wave oscillations for conversion to electrical energy has long been pursued as an alternative or self-contained power source. The attraction to harvesting energy from ocean waves stems from the sheer power of the wave motion, which can easily exceed 50 kW per meter of wave front. The principal barrier to harvesting this power is the very low and varying frequency of ocean waves, which generally vary from 0.1Hz to 0.5Hz. In this paper the application of a novel class of two-stage electrical energy generators to buoyant structures is presented. The generators use the buoy's interaction with the ocean waves as a low-speed input to a primary system, which, in turn, successively excites an array of vibratory elements (secondary system) into resonance - like a musician strumming a guitar. The key advantage of the present system is that by having two decoupled systems, the low frequency and highly varying buoy motion is converted into constant and much higher frequency mechanical vibrations. Electrical energy may then be harvested from the vibrating elements of the secondary system with high efficiency using piezoelectric elements. The operating principles of the novel two-stage technique are presented, including analytical formulations describing the transfer of energy between the two systems. Also, prototypical design examples are offered, as well as an in-depth computer simulation of a prototypical heaving-based wave energy harvester which generates electrical energy from the up-and-down motion of a buoy riding on the ocean's surface.

Murray, R.; Rastegar, J.

2009-03-01

183

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

SciTech Connect

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

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

1982-09-28

184

Diffuse Waves and Energy Densities Near Boundaries  

NASA Astrophysics Data System (ADS)

Green function can be retrieved from averaging cross correlations of motions within a diffuse field. In fact, it has been shown that for an elastic inhomogeneous, anisotropic medium under equipartitioned, isotropic illumination, the average cross correlations are proportional to the imaginary part of Green function. For instance coda waves are due to multiple scattering and their intensities follow diffusive regimes. Coda waves and the noise sample the medium and effectively carry information along their paths. In this work we explore the consequences of assuming both source and receiver at the same point. From the observable side, the autocorrelation is proportional to the energy density at a given point. On the other hand, the imaginary part of the Green function at the source itself is finite because the singularity of Green function is restricted to the real part. The energy density at a point is proportional with the trace of the imaginary part of Green function tensor at the source itself. The Green function availability may allow establishing the theoretical energy density of a seismic diffuse field generated by a background equipartitioned excitation. We study an elastic layer with free surface and overlaying a half space and compute the imaginary part of the Green function for various depths. We show that the resulting spectrum is indeed closely related to the layer dynamic response and the corresponding resonant frequencies are revealed. One implication of present findings lies in the fact that spatial variations may be useful in detecting the presence of a target by its signature in the distribution of diffuse energy. These results may be useful in assessing the seismic response of a given site if strong ground motions are scarce. It suffices having a reasonable illumination from micro earthquakes and noise. We consider that the imaginary part of Green function at the source is a spectral signature of the site. The relative importance of the peaks of this energy spectrum, ruling out non linear effects, may influence the seismic response for future earthquakes. Partial supports from DGAPA-UNAM, Project IN114706, Mexico; from Proyect MCyT CGL2005-05500-C02/BTE, Spain; from project DyETI of INSU-CNRS, France, and from the Instituto Mexicano del Petróleo are greatly appreciated.

Sanchez-Sesma, F. J.; Rodriguez-Castellanos, A.; Campillo, M.; Perton, M.; Luzon, F.; Perez-Ruiz, J. A.

2007-12-01

185

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

186

Nuclear Power Trends Energy Economics and Sustainability  

E-print Network

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

187

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

188

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

189

Experimental study on a pendulum wave energy converter  

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

190

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

191

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

192

Free energy in plasmas under wave-induced diffusion  

SciTech Connect

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

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

1993-05-01

193

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

194

Wave turbulence revisited: Where does the energy flow?  

E-print Network

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

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

2014-04-03

195

Measurements of 20 GHz high-power microwaves output from a large diameter plasma filled backward wave oscillator  

NASA Astrophysics Data System (ADS)

A large diameter plasma filled backward wave oscillator (BWO) is investigated experimentally. The parameters of slow wave structure are chosen so that the oscillation frequency is about 20 GHz at 60 keV beam energy. Plasma is produced by the beam and it has favorable effects on beam propagation and Cerenkov oscillation. The output power of the BWO with plasma is observed to be 3-6 times that of vacuum BWO. The power level is several kW and efficiency is about 0.01 percent. The output power is strongly enhanced when the guiding magnetic field approaches the fundamental electron cyclotron resonance. A maximum power of 490 kW with an efficiency of 4 percent is achieved even for a relatively low beam energy of 60 keV.

Kurashina, Ken-Ichi; Kim, Wonsop; Ogura, Kazuo; Minami, Kazuo; Watanabe, Tsuguhiro; Sugito, Syouji

1994-06-01

196

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

2013-06-01

197

Electromagnetic energy storage and power dissipation in nanostructures  

NASA Astrophysics Data System (ADS)

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

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

2015-01-01

198

Estimating the Power per Mode Number and Power vs L-shell of Broadband, Storm-time ULF Waves  

NASA Astrophysics Data System (ADS)

In studies of particles' radial diffusion processes in the magnetosphere it is well known that Ultra-Low Frequency (ULF) waves of frequency m*?d can resonantly interact with particles of drift frequency ?d, where m is the azimuthal mode number of the waves; however due to difficulties in estimating m an over-simplifying assumption is often made in radial diffusion simulations, namely that all ULF wave power is located at m=1 or, in some cases, m=2. In another assumption that is commonly made, power measured from geosynchronous satellites is assumed to be uniform across L-shells. In the present work, a technique is presented for extracting information on the distribution of ULF wave power in a range of azimuthal mode numbers, through calculations of the cross-power and phase differences between a number of azimuthally aligned pairs of magnetometers, either in space or on the ground. We find that the temporal evolution of power at each mode number gives unique insight into the temporal evolution of ULF waves during a storm as well as a more accurate characterization of broadband ULF waves. Furthermore, using multi-spacecraft measurements during a particular storm, we calculate the L-dependence of ULF wave power. These measurements and calculations can be used in more accurate ULF wave representation in radial diffusion simulations.

Sarris, T. E.; Li, X.; Liu, W.; Argyriadis, E.

2013-12-01

199

Power Amplifier Module with 734-mW Continuous Wave Output Power  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

200

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

NASA Astrophysics Data System (ADS)

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

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

2011-04-01

201

Dark energy from quantum wave function collapse of dark matter  

E-print Network

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

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

2009-09-03

202

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

203

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.

204

Extraction of energy from gravitational waves by laser interferometer detectors  

NASA Astrophysics Data System (ADS)

In this paper, we discuss the energy interaction between gravitational waves and laser interferometer gravitational wave detectors. We show that the widely held view that the laser interferometer gravitational wave detector absorbs no energy from gravitational waves is only valid under the approximation of a frequency-independent optomechanical coupling strength and a pump laser without detuning with respect to the resonance of the interferometer. For a strongly detuned interferometer, the optical-damping dynamics dissipates gravitational wave energy through the interaction between the test masses and the optical field. For a non-detuned interferometer, the frequency-dependence of the optomechanical coupling strength causes a tiny energy dissipation, which is proved to be equivalent to the Doppler friction raised by Braginsky et al.

Ma, Yiqiu; Blair, David G.; Zhao, Chunnong; Kells, William

2015-01-01

205

Powerful surface-wave oscillators with two-dimensional periodic structures  

SciTech Connect

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

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

2012-04-02

206

Research and Technology in Wave Energy for Electric Mobility  

E-print Network

Mechanical Engineering, University of Hawaii at Manoa Abstract Developing renewable sources of energy generated by ocean current and energy extraction through ocean thermal conversion (OTEC). For wave energy energy did not seem to be attractive to many scientists and engineers, especially those in the US. More

Frandsen, Jannette B.

207

High-Power Traveling Wave Tubes Powered by a Relativistic Electron Beam  

NASA Astrophysics Data System (ADS)

This thesis presents the results of a high power traveling wave tube (TWT) amplifier experiment. The experiment tested the feasibility of 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 TWTs of this type were used, with lengths of 11 and 22 periods. These single stage tubes were linear and operated in the TM_{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 +/-8 ^circ; 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, we 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 the severed tube was about 100 MHz centered at 8.76 GHz. The severed amplifiers showed the "sideband"-like behaviour at all the beam currents used. The "sideband" frequency separation from the center frequency increased with beam current. The relative importance of the "sidebands" increased with increasing beam current and the total power in the amplifier. As much as 32% of the total power could be in any one "sideband". When the "sidebands" were taken into account, the total power at the magnetron frequency was 209 MW, giving an efficiency of 24%.

Shiffler, Donald Albert, Jr.

208

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

SciTech Connect

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

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

2014-03-01

209

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

E-print Network

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

California at Los Angles, University of

210

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

211

Power Measurement Methods for Energy Efficient Applications  

PubMed Central

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

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

2013-01-01

212

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

PubMed

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

Holm, Sverre; Näsholm, Sven Peter

2014-04-01

213

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

NASA Astrophysics Data System (ADS)

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

Yokoyama, Naoto; Takaoka, Masanori

2014-12-01

214

SPS Energy Conversion Power Management Workshop  

NASA Technical Reports Server (NTRS)

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

1980-01-01

215

Medium-induced jet evolution: wave turbulence and energy loss  

E-print Network

We study the gluon cascade generated via successive medium-induced branchings by an energetic parton propagating through a dense QCD medium. We focus on the high-energy regime where the energy $E$ of the leading particle is much larger than the characteristic medium scale $\\omega_c=\\hat q L^2/2$, with $\\hat q$ the jet quenching parameter and $L$ the distance travelled through the medium. In this regime the leading particle loses only a small fraction $\\sim\\alpha_s(\\omega_c/E)$ of its energy and can be treated as a steady source of radiation for gluons with energies $\\omega\\le\\omega_c$. For this effective problem with a source, we obtain exact analytic solutions for the gluon spectrum and the energy flux. The solutions exhibit wave turbulence: the basic physical process is a continuing fragmentation which is `quasi-democratic' (i.e. quasi-local in energy) and which provides an energy transfer from the source to the medium at a rate (the energy flux $\\mathcal{F}$) which is quasi-independent of $\\omega$. The locality of the branching process implies a spectrum of the Kolmogorov-Obukhov type, i.e. a power-law spectrum which is a fixed point of the branching process and whose strength is proportional to the energy flux: $D(\\omega)\\sim\\mathcal{F}/\\sqrt\\omega$ for $\\omega\\ll\\omega_c$. Via this turbulent flow, the gluon cascade loses towards the medium an energy $\\Delta E\\sim\\alpha_s^2\\omega_c$, which is independent of the initial energy $E$ of the leading particle and of the details of the thermalization mechanism at the low-energy end of the cascade. This energy is carried away by very soft gluons, which propagate at very large angles with respect to the jet axis. Our predictions for the value of $\\Delta E$ and for its angular distribution appear to agree quite well, qualitatively and even semi-quantitatively, with the phenomenology of di-jet asymmetry in nucleus-nucleus collisions at the LHC.

Leonard Fister; Edmond Iancu

2014-09-06

216

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

217

Energy Decisions: Is Solar Power the Solution?  

ERIC Educational Resources Information Center

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

Childress, Vincent W.

2011-01-01

218

Department of Energy Bonneville Power Administration  

E-print Network

Program (Program) and to track performance indicators under the Federal Columbia River Power System (FCRPS-15-09 Management Question Performance Measure or Standard High Level Indicator Metrics Data Source CommentsDepartment of Energy Bonneville Power Administration P.O. Box 3621 Portland, Oregon 97208

219

Negative energy waves in the coronal plume/interplume system  

NASA Astrophysics Data System (ADS)

Recent high-resolution ground and space based telescopes have revealed that many solar features have substructures displaying a periodic or quasi-periodic pattern in transversal direction. In the present contribution we study the appearance of negative energy waves in a spatially periodic structure modelling the plume/interplume region above coronal holes. Negative energy waves (or instabilities) come into effect after a certain threshold for flow speed is reached. We also show that the periodicity of the structure has an important influence on the conditions required for negative energy waves.

Marcu, A.

2007-03-01

220

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

221

Interaction of two walkers: Wave-mediated energy and force  

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

222

The "Big Wave" theory for Dark Energy Blake Temple  

E-print Network

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

Temple, Blake

223

Plasma radiation of power-law electrons in magnetic loops: application to solar decimeter-wave continua  

NASA Astrophysics Data System (ADS)

It is shown that flare-produced fast electrons with a power-law energy distribution trapped in magnetic loops are capable to produce plasma waves at the upper hybrid frequency due to a loss-cone instability. Conditions for instability are obtained in dependence of the parameters of the power-law distribution and the magnetic-loop parameters. The growth rate of the plasma waves has been calculated and their energy density has been estimated in the frame of quasi-linear saturation. This instability has been considered as the cause of the solar decimetric continuum which exhibits a strong temporal and spatial correlation with regions of flare-energy release and sources of microwave bursts. The strong absorption of the first harmonic in the decimeter range and also the peculiarities of the conversion of the plasma waves into electromagnetic waves yield a preference of the generation of the decimetric continuum at the second harmonic of the plasma frequency. In this case the polarization of the radiation corresponds to the ordinary wave mode in a wide cone of propagation angles around the direction perpendicular to the magnetic field.

Zaitsev, V. V.; Kruger, A.; Hildebrandt, J.; Kliem, B.

1997-12-01

224

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

225

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

226

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

227

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

228

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

229

Optimal Power Allocation for Renewable Energy Source  

E-print Network

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

Sinha, Abhinav

2011-01-01

230

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

E-print Network

Wave Energy Test Site (WETS) Marine Corps Base Hawaii (MCBH) Alexandra DeVisser, NAVFAC-EXWC Brian/ocean engineering. 2 #12;Commercial Sites: Deploy/Retrieve May to Sep Only WETS: Deploy/Retrieve Year Round 3 Why

231

Fluid Power Systems. Energy Technology Series.  

ERIC Educational Resources Information Center

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

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

232

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

233

Stopping Power from SPS to LHC energies  

E-print Network

We investigate the energy dependence of hadron production and of stopping power based on HIJING/BBbar v2.0 model calculations. Pseudorapidity spectra and transverse momentum distributions for produced charged particles as well as net baryons (per pair of partcipants) and their rapidity loss are compared to data at RHIC and predictions for LHC energies are discussed.

V. Topor Pop; J. Barrette; C. Gale; S. Jeon; M. Gyulassy

2007-05-18

234

Wind energy for remote telecommunications power  

Microsoft Academic Search

Technological developments of small wind energy conversion systems have accelerated in the past decade. These systems are being evaluated for their technical feasibility, competitive costs of electric power generation, high reliability of design and performance, and minimal environmental impact. Small wind energy conversion systems are commercially available and, for select applications, are cost competitive. They have been used to provide

Thorn

1981-01-01

235

Energy storage and generation from thermopower waves  

E-print Network

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

Abrahamson, Joel T. (Joel Theodore)

2012-01-01

236

Wave energy driven resonant sea water pump  

SciTech Connect

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

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

1996-12-31

237

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

NASA Technical Reports Server (NTRS)

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

Wintucky, Edwin G.; Simons, Rainee N.

2014-01-01

238

Energy flux of timeharmonic waves in anisotropic dissipative media  

E-print Network

Energy flux of time­harmonic waves in anisotropic dissipative media Vlastislav Ÿ Cerven 2, Czech Republic. E­mail vcerveny@seis.karlov.m#.cuni.cz Summary The energy flux of time to consider the average energy flux, which is real­valued and time­independent. An extension

Cerveny, Vlastislav

239

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

240

A Experimental Investigation of a Tandem Relativistic Backward Wave Oscillator - Travelling Wave Tube Amplifier System for Generating High-Power Microwaves  

NASA Astrophysics Data System (ADS)

The experimental investigation described in this dissertation demonstrates the feasibility of generating long (>=50 nsec) pulses of high-power (>=100 MW), X-band frequency microwaves. In these experiments, a relativistic Backward Wave Oscillator (BWO) is used in tandem with a Traveling Wave Tube (TWT) amplifier to generate microwave radiation. The tandem BWO-TWT system is driven in the TM_{01 } mode by a single annular, relativistic electron beam, which is guided through the two rippled-wall slow wave structures by an applied axial magnetic field. A special RF sever placed between the BWO and TWT slow wave structures prevents electromagnetic coupling between the oscillator and amplifier while allowing the electron beam to pass from one structure to the other. In this way, the BWO serves to modulate the beam that subsequently drives the TWT producing high-power, phase stable microwave radiation. To obtain microwave pulses with pulsewidths comparable to the electron beam duration, the BWO is operated below saturation levels in order to minimize the pulse -shortening effects that are characteristic of very high -power BWOs. A set of BWO characterization experiments are conducted to determine the optimum operating conditions for this oscillator/modulator. When driven with a beam of ~100 nsec duration, the tandem BWO-TWT device is found capable of producing 50-60 nsec wide microwave pulses with peak output powers in excess of 100 MW. Overall beam-to-microwave efficiencies as high as 35% are observed. The operating frequency of the tandem device is tuned between 11-12 GHz by varying the effective energy of the beam. The tandem BWO-TWT system described here can be scaled up in size to produce peak output power levels in the gigawatt range. This type of system is ideal for use in phased array antenna applications that require an easily controlled source of high power density microwave radiation.

Barreto, Gilberto

241

An experimental investigation of a tandem relativistic backward wave oscillator-travelling wave tube amplifier system for generating high-power microwaves  

NASA Astrophysics Data System (ADS)

The experimental investigation described in this dissertation demonstrates the feasibility of generating long (greater than or equal to 50 nsec) pulses of high-power (greater than or equal to 100 MW), X-band frequency microwaves. In these experiments, a relativistic Backward Wave Oscillator (BWO) is used in tandem with a Traveling Wave Tube (TWT) amplifier to generate microwave radiation. The tandem BWO TWT system is driven in the TM(sub 01) mode by a single annular, relativistic electron beam, which is guided through the two rippled-wall slow wave structures by an applied axial magnetic field. A special RF sever placed between the BWO and TWT slow wave structures prevents electromagnetic coupling between the oscillator and amplifier while allowing the electron beam to pass from one structure to the other. In this way, the BWO serves to modulate the beam that subsequently drives the TWT producing high-power, phase stable microwave radiation. To obtain microwave pulses with pulsewidths comparable to the electron beam duration, the BWO is operated below saturation levels in order to minimize the pulse-shortening effects that are characteristic of very high-power BWOs. A set of BWO characterization experiments are conducted to determine the optimum operating conditions for this oscillator/modulator. When driven with a beam of approx. 100 nsec duration, the tandem BWO-TWT device is found capable of producing 50-60 nsec wide microwave pulses with peak output powers in excess of 100 MW. Overall beam-to-microwave efficiencies as high as 35 percent are observed. The operating frequency of the tandem device is tuned between 11-12 GHz by varying the effective energy of the beam. The tandem BWO-TWT system described here can be scaled up in size to produce peak output power levels in the gigawatt range. This type of system is ideal for use in phased array antenna applications that require an easily controlled source of high power density microwave radiation.

Barreto, Gilberto

242

How to Estimate Energy Lost to Gravitational Waves (revised)  

E-print Network

The energy--momentum radiated in gravitational waves by an isolated source is given by a formula of Bondi. This formula is highly non--local: the energy--momentum is not given as the integral of a well--defined local density. It has therefore been unclear whether the Bondi formula can be used to get information from gravity--wave measurements. In this note, we obtain, from local knowledge of the radiation field, a lower bound on the Bondi flux.

Adam D. Helfer

1993-07-19

243

Wave energy attenuation and shoreline alteration characteristics of submerged breakwaters  

E-print Network

WAVE ENERGY ATTENUATION AND SHORELINE ALTERATION CHARACTERISTICS OF SUBMERGED BREAKWATERS A Thesis by KATHERINE MARGARET KRAFFT Submitted to the Office of Graduate Studies of Texas AIM University in partial fulfillment of the requirements... for the degree of MASTER OF SCIENCE August 1993 Major Subject: Ocean Engineering WAVE ENERGY ATTENUATION AND SHORELINE ALTERATION CHARACTERISTICS OF SUBMERGED BREAKWATERS A Thesis by KATHERINE MARGARET KRAFFT Approved as to style and content by: John...

Krafft, Katherine Margaret

2012-06-07

244

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

245

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

246

Arnold Schwarzenegger DEVELOPING WAVE ENERGY IN  

E-print Network

-Related Environmental Research Neal Fishman Ocean Program Manager Mike Gravely Office Manager Drew Bohan Energy Systems Energy Commission, PIER Energy-Related Environmental Research Program & California Ocean Protection-ECONOMIC AND ENVIRONMENTAL EFFECTS Prepared For: California Energy Commission Public Interest Energy Research Program

247

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

248

'People Power' Saves Plant Energy  

E-print Network

and air cooler fans, turning off tracing steam, keeping turbine hand valves closed where possible, and continued emphasis on all phases of proper fired-heater operation. Po tential subjects for Energy-Grams are many. They should be eye... In parallel when only one is required. A 300 hp turbine drive spare pump was being run in parallel with a motor driven pump. Investigation showed that the spare pump only needed to be run during the summer months. Savings resulted from shutting down...

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

1981-01-01

249

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

NASA Astrophysics Data System (ADS)

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

Wang, De-bo; Liao, Xiao-ping

2012-06-01

250

A dual-resonant reflector in powerful relativistic backward wave oscillator  

SciTech Connect

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

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

2011-06-15

251

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

E-print Network

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

Yavuz, Deniz

252

Study of temperature distribution of a pyramidal EM-wave absorber under high power injection  

Microsoft Academic Search

Utilization of electromagnetic absorbers under high power is increasing. The absorbers are used in anechoic chambers for estimation of performance of high power radars. Variation of the absorption characteristics of the absorbers under such condition is expected, due to the generation of heat or temperature change. In this paper, first temperature distribution of a pyramidal EM-wave absorber under high power

Shinya Watanabe; Tetsuhiro Sasagawa; Osamu Hashimoto; Toshifumi Saito

2007-01-01

253

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

254

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

NASA Astrophysics Data System (ADS)

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

Richardson, M.; Sankaranarayanan, S. K. R. S.; Bhethanabotla, V. R.

2014-06-01

255

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

SciTech Connect

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

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

2014-06-23

256

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

NASA Astrophysics Data System (ADS)

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

Ahmed, Riaz U.; Banerjee, Sourav

2014-11-01

257

On the conversion of blast wave energy into radiation in active galactic nuclei and gamma-ray bursts  

E-print Network

It has been suggested that relativistic blast waves may power the jets of AGN and gamma-ray bursts (GRB). We address the important issue how the kinetic energy of collimated blast waves is converted into radiation. It is shown that swept-up ambient matter is quickly isotropised in the blast wave frame by a relativistic two-stream instability, which provides relativistic particles in the jet without invoking any acceleration process. The fate of the blast wave and the spectral evolution of the emission of the energetic particles is therefore solely determined by the initial conditions. We compare our model with existing multiwavelength data of AGN and find remarkable agreement.

Martin Pohl; Reinhard Schlickeiser

1999-11-24

258

Modeling of a Linear Switched Reluctance Machine and Drive for Wave Energy Conversion Using Matrix and Tensor Approach  

Microsoft Academic Search

Low power density is an obstacle of linear switched reluctance machines (LSRMs) to be competitive candidates for the wave energy conversion, which is increasingly a potential source of renewable energy. Meanwhile, the strong coupling and nonlinearity of LSRMs and drives make it very difficult to derive a comprehensive mathematical model for the behavior of the system. This paper presents a

Jinhua Du; Deliang Liang; Longya Xu; Qingfu Li

2010-01-01

259

Energy of tsunami waves generated by bottom motion  

E-print Network

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

Boyer, Edmond

260

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

261

Energy and power needs of electric vehicles  

Microsoft Academic Search

Both energy and energy rate (power) requirements are described based on the mechanical output requirements of typical electric automobiles, the electrical input requirements at the inverter, and the requirements from a utility into a charger. The impact of lithium-ion battery input-output efficiency is considered. A fully loaded full-size car with a mass of 2000 kg, for example, requires only about

Philip T. Krein

2012-01-01

262

Energy harvesting for self-powered nanosystems  

Microsoft Academic Search

In this article, an introduction is presented about the energy harvesting technologies that have potential for powering nanosystems.\\u000a Our discussion mainly focuses on the approaches other than the well-known solar cell and thermoelectrics. We mainly introduce\\u000a the piezoelectric nanogenerators developed using aligned ZnO nanowire arrays. This is a potential technology for converting\\u000a mechanical movement energy (such as body movement, muscle

Zhong Lin Wang

2008-01-01

263

STATUS OF HIGH POWER TESTS OF NORMAL CONDUCTING SINGLE-CELL STANDING WAVE STRUCTURES  

E-print Network

STATUS OF HIGH POWER TESTS OF NORMAL CONDUCTING SINGLE-CELL STANDING WAVE STRUCTURES B. Spataro. GEOMETRIES AND MATERIALS The single-cell standing wave structure consists of three parts: the input coupler cell is based on the geometry of a periodic accel- erator structure cell. In this paper we discuss

Istituto Nazionale di Fisica Nucleare (INFN)

264

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

E-print Network

that then presents more resonant modes. Square-wave electronic ballast is an alternative to resonant converters andLow-frequency square-wave electronic ballast with resonant ignition using digital mode and power Zane(2) (1) Department of Electronics Technology, System and Automation Engineering. University

265

The energy of high frequency waves in the low solar Chromosphere  

E-print Network

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

Aleksandra Andic

2007-03-28

266

High energy spin waves in BCC iron  

SciTech Connect

We have studied the dispersion relation of the spin wave excitations in bcc iron by neutron inelastic scattering at the spallation neutron source ISIS. Magnetic intensity was followed up to 550meV along the (100) direction. The general form of the dispersion curve is in qualitative agreement with that calculated from a spin-polarised band model, and in particular we have confirmed the prediction of propagating modes extending above 300meV. 7 refs., 3 figs.

Perring, T.G. (Oxford Univ. (UK). Clarendon Lab.); Boothroyd, A.T.; Paul, D.McK. (Warwick Univ., Coventry (UK). Dept. of Physics); Taylor, A.D.; Osborn, R. (Rutherford Appleton Lab., Chilton (UK)); Newport, R.J. (Kent Univ., Canterbury (UK). Dept. of Physics); Blackman, J.A. (Reading Univ. (UK). Dept. of Physics); Mook, H.A. (Oak Ridge National Lab., TN (USA))

1990-01-01

267

High-energy effective action from scattering of QCD shock waves  

SciTech Connect

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

Ian Balitsky

2005-06-16

268

High-energy effective action from scattering of QCD shock waves  

SciTech Connect

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

Ian Balitsky

2005-05-15

269

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

DOEpatents

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

Koplow, Jeffrey P. (San Ramon, CA)

2012-07-03

270

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

Microsoft Academic Search

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

Jun Zhang; Hui-Huang Zhong; Ling Luo

2004-01-01

271

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

NASA Astrophysics Data System (ADS)

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

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

2014-12-01

272

Method of, and apparatus for, extracting energy from waves  

SciTech Connect

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

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

1981-11-17

273

Energy Partitioning of Seismic Waves in Fractured Rocks  

SciTech Connect

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

NONE

1997-08-31

274

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

NASA Technical Reports Server (NTRS)

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

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

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

2007-01-01

275

Damping Pressure Pulsations in a Wave-Powered Desalination System  

E-print Network

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

Padhye, Nikhil

276

Department of Energy Bonneville Power Administration  

E-print Network

indicators identified in the draft appear to be at a regional level of performance reporting, and reflect for regional and non- hydrosystem performance indicators are not the sole responsibility of BPA. GivenDepartment of Energy Bonneville Power Administration P.O. Box 3621 Portland, Oregon 97208

277

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

278

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

279

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

PubMed

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

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

2014-11-01

280

Effects of chemical fuel composition on energy generation from thermopower waves  

NASA Astrophysics Data System (ADS)

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

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

2014-11-01

281

Thermal energy storage for power plant applications  

SciTech Connect

This study was conducted by Pacific Northwest Laboratory (PNL) to evaluate alternative methods of using coal to generate peak and intermediate load power. The approach was to review the technical and economic feasibility of using thermal energy storage (TES) with a conventional coal-fired power plant and an integrated gasification combined cycle (IGCC) power plant. In the first case, conventional pulverized coal combustion equipment was continuously operated to heat molten nitrate salt which was then stored in a tank. During peak demand periods, hot salt was withdrawn from storage and used to generate steam for a Rankine steam power cycle. This coal-fired salt heater can be approximately one-third the size of a coal-fired boiler in a conventional cycling plant. The use of nitrate salt TES also reduces the levelized cost of power from 5-24 percent depending on the operating schedule. The second case evaluates the use of thermal energy storage with an integrated gasification combined cycle (IGCC) power plant. In this case, the nitrate salt was heated by a combination of the gas turbine exhaust and the hot fuel gas. The IGCC plant also contained a low-temperature storage unit that uses a mixture of oil and rock as the thermal storage medium. Thermal energy stored in the low-temperature TES was used to preheat the feedwater after it leaves the condenser and to produce process steam for other applications in the IGCC plant. This concept study also predicted lower cost power compared to the natural gas-fired alternative if significant escalation rates in the price of fuel were assumed. A sensitivity analysis showed a significant reduction in the installed capital cost of a direct-contact heat exchanger instead of the conventional finnned-tube design.

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

1990-01-01

282

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

E-print Network

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

Robertson, William

283

Efficiency enhancement techniques for RF and millimeter wave power amplifiers  

E-print Network

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

Ogunnika, Olumuyiwa Temitope, 1978-

2012-01-01

284

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

SciTech Connect

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

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

2010-03-15

285

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

286

Maximum gravitational-wave energy emissible in magnetar flares  

NASA Astrophysics Data System (ADS)

Recent searches of gravitational-wave data raise the question of what maximum gravitational-wave energies could be emitted during gamma-ray flares of highly magnetized neutron stars (magnetars). The highest energies (˜1049erg) predicted so far come from a model [K. Ioka, Mon. Not. R. Astron. Soc.MNRAA40035-8711 327, 639 (2001), http://adsabs.harvard.edu/abs/2001MNRAS.327..639I] in which the internal magnetic field of a magnetar experiences a global reconfiguration, changing the hydromagnetic equilibrium structure of the star and tapping the gravitational potential energy without changing the magnetic potential energy. The largest energies in this model assume very special conditions, including a large change in moment of inertia (which was observed in at most one flare), a very high internal magnetic field, and a very soft equation of state. Here we show that energies of 1048-1049erg are possible under more generic conditions by tapping the magnetic energy, and we note that similar energies may also be available through cracking of exotic solid cores. Current observational limits on gravitational waves from magnetar fundamental modes are just reaching these energies and will beat them in the era of advanced interferometers.

Corsi, Alessandra; Owen, Benjamin J.

2011-05-01

287

Maximum gravitational-wave energy emissible in magnetar flares  

SciTech Connect

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

Corsi, Alessandra; Owen, Benjamin J. [LIGO Laboratory, California Institute of Technology, MS 100-36, Pasadena, California 91125 (United States); Center for Gravitational Wave Physics, Institute for Gravitation and the Cosmos, Department of Physics, Pennsylvania State University, University Park, Pennsylvania 16802 (United States) and Max Planck Institut fuer Gravitationsphysik (Albert Einstein Institut), Callinstr. 38, 30167 Hannover (Germany)

2011-05-15

288

Experimental Testing and Model Validation for Ocean Wave Energy Harvesting Buoys  

E-print Network

Experimental Testing and Model Validation for Ocean Wave Energy Harvesting Buoys Douglas A. Gemme1 are presented for numerical simulations and field experiments using point absorption ocean wave energy and experimental data. Index Terms ­ energy conversion, wave energy harvesting, linear generator, ocean energy

Grilli, Stéphan T.

289

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

290

RF energy harvesting techniques for wirelessly powered devices  

Microsoft Academic Search

A power source combined with energy harvesting can provide wireless devices for low maintenance cost or extended battery life. We reviewed RF energy harvesting circuits for delivering power to wireless system operating at very low power levels with high efficiency. We need to apply low power control techniques to perform smart management for the wirelessly powered devices. Index Terms —

Shiho Kim

2011-01-01

291

Wave Energy Converter (WEC) Array Effects on Wave Current and Sediment Circulation: Monterey Bay CA.  

SciTech Connect

The goal s of this study were to develop tools to quantitatively characterize environments where wave energy converter ( WEC ) devices may be installed and to assess e ffects on hydrodynamics and lo cal sediment transport. A large hypothetical WEC array was investigated using wave, hydrodynamic, and sediment transport models and site - specific average and storm conditions as input. The results indicated that there were significant changes in sediment s izes adjacent to and in the lee of the WEC array due to reduced wave energy. The circulation in the lee of the array was also altered; more intense onshore currents were generated in the lee of the WECs . In general, the storm case and the average case show ed the same qualitative patterns suggesting that these trends would be maintained throughout the year. The framework developed here can be used to design more efficient arrays while minimizing impacts on nearshore environmen ts.

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

2014-09-01

292

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

NASA Astrophysics Data System (ADS)

We present the experimental observation of the localized amplification of externally excited, propagating spin waves in a transversely in-plane magnetized Ni81Fe19 magnonic waveguide by means of parallel pumping. By employing microfocussed Brillouin light scattering spectroscopy, we analyze the dependency of the amplification on the applied pumping power and on the delay between the input spin-wave packet and the pumping pulse. We show that there are two different operation regimes: At large pumping powers, the spin-wave packet needs to enter the amplifier before the pumping is switched on in order to be amplified while at low powers the spin-wave packet can arrive at any time during the pumping pulse.

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

2014-12-01

293

Energy Storage Applications in Power Systems with Renewable Energy Generation  

NASA Astrophysics Data System (ADS)

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

Ghofrani, Mahmoud

294

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

Microsoft Academic Search

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

Faruk Yildiz

2008-01-01

295

The environmental interactions of tidal and wave energy generation devices  

SciTech Connect

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

Frid, Chris, E-mail: c.l.j.frid@liv.ac.uk [School of Environmental Sciences, University of Liverpool, Crown Street, Liverpool, L69 7ZB (United Kingdom); Andonegi, Eider, E-mail: eandonegi@azti.es [AZTI-Tecnalia, Txatxarramendi ugartea, z/g E-48395 Sukarrieta (Bizkaia) (Spain); Depestele, Jochen, E-mail: jochen.depestele@ilvo.vlaanderen.be [Institute for Agricultural and Fisheries Research, Ankerstraat 1, B-8400 Oostende (Belgium); Judd, Adrian, E-mail: Adrian.Judd@cefas.co.uk [Centre for Environment, Fisheries and Aquaculture Science , Lowestoft Laboratory, Pakefield Road, Lowestoft NR33 0HT United Kingdom (United Kingdom); Rihan, Dominic, E-mail: Dominic.RIHAN@ec.europa.eu [Irish Sea Fisheries Board, P.O. Box 12 Dun Laoghaire, Co. Dublin (Ireland); Rogers, Stuart I., E-mail: stuart.rogers@cefas.co.uk [Centre for Environment, Fisheries and Aquaculture Science , Lowestoft Laboratory, Pakefield Road, Lowestoft NR33 0HT United Kingdom (United Kingdom); Kenchington, Ellen, E-mail: Ellen.Kenchington@dfo-mpo.gc.ca [Fisheries and Oceans Canada, Bedford Institute of Oceanography, P.O. Box 1006, Dartmouth Canada, NS B2Y 4A2 (Canada)

2012-01-15

296

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

297

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

298

High-power parametric conversion from near-infrared to short-wave infrared  

E-print Network

dispersion measurement of optical fibers with a tunable fiber laser," IEEE Photon. Technol. Lett. 18, 1825High-power parametric conversion from near-infrared to short-wave infrared Adrien Billat,1,* Steevy up to 700 mW of power at 1940 nm. The source is tunable over wavelength intervals comprised between

Dalang, Robert C.

299

Spectral power density of the random excitation for the photoacoustic wave equation  

NASA Astrophysics Data System (ADS)

The superposition of the Green's function and its time reversal can be extracted from the photoacoustic point sources applying the representation theorems of the convolution and correlation type. It is shown that photoacoustic pressure waves at locations of random point sources can be calculated with the solution of the photoacoustic wave equation and utilization of the continuity and the discontinuity conditions of the pressure waves in the frequency domain although the pressure waves cannot be measured at these locations directly. Therefore, with the calculated pressure waves at the positions of the sources, the spectral power density can be obtained for any system consisting of two random point sources. The methodology presented here can also be generalized to any finite number of point like sources. The physical application of this study includes the utilization of the cross-correlation of photoacoustic waves to extract functional information associated with the flow dynamics inside the tissue.

Erkol, Hakan; Unlu, Mehmet Burcin

2014-09-01

300

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

E-print Network

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

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

2014-01-01

301

Comparison of heaving buoy and oscillating flap wave energy converters  

NASA Astrophysics Data System (ADS)

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

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

2013-04-01

302

Waves  

NSDL National Science Digital Library

We will review some basic properties of waves and then further explore sound and light. For a quick overview of some properties of all waves, click on this first site. Make sure you fill out your hand out as you work! Waves and Wave Motion : Describing Waves Practice what you've already learned about waves with this site: Waves This site will let you play around some more with transverse waves: Wave on a String Sound waves are mechanical waves, ...

Petersen, Mrs.

2014-05-27

303

Energy-Management for Power Aware Portable Sensor Systems  

Microsoft Academic Search

The design of power aware wireless sensor systems has gained increasing importance in recent research. Challenges in designing such devices are a throughout energy scalable design of hardware, signal processing and communication and an energy-effective energy management. The power supply should be capable to `harvest' ambient energy and to accumulate superfluous energy in an energy storage unit in order to

Olfa Kanoun; Hans-Rolf Tränkler

2006-01-01

304

Energy-dependent ?-wave confinement-induced resonances  

NASA Astrophysics Data System (ADS)

The universal aspects of two-body collisions in the presence of a harmonic confinement are investigated for both bosons and fermions. The main focus of this study are the confinement-induced resonances (CIRs) which are attributed to different angular momentum states ?, and we explicitly show that in alkaline collisions only four universal ?-wave CIRs emerge given that the interatomic potential is deep enough. Going beyond the single mode regime the energy dependence of ?-wave CIRs is studied. In particular we show that all the ?-wave CIRs may emerge even when the underlying two-body potential cannot support any bound state. We observe that the intricate dependence on the energy yields resonant features where the colliding system within the confining potential experiences an effective free-space scattering. Our analysis is done within the framework of the generalized K-matrix theory, and the relevant analytical calculations are in very good agreement with the corresponding ab initio numerical scattering simulations.

Heß, Benjamin; Giannakeas, Panagiotis; Schmelcher, Peter

2014-05-01

305

Electric Power From Ambient Energy Sources  

SciTech Connect

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

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

2000-10-03

306

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

307

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

308

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

309

Local energy decay for linear wave equations with variable coefficients  

Microsoft Academic Search

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

Ryo Ikehata

2005-01-01

310

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

SciTech Connect

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

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

2010-08-15

311

An alternative method for calculating the energy of gravitational waves  

E-print Network

In the expansive nondecelerative universe model, creation of matter occurs due to which the Vaidya metrics is applied. This fact allows for localizing gravitational energy and calculating the energy of gravitational waves using an approach alternative to the well established procedure based on quadrupole formula. Rationalization of the gradual increase in entropy of the Universe using relation describing the total curvature of space-time is given too.

Miroslav Sukenik; Jozef Sima

1999-09-21

312

Method and apparatus for generating electric power by waves  

SciTech Connect

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

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

1984-12-25

313

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

SciTech Connect

A unique, high-power microwave source, called PASOTRON[trademark] (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 accelerator produces an E-beam that is operated in the ion-focused regime; where the beam-produced plasma filling the SWS space-charge neutralizes the beam, and the self-pinch force compresses the beamlets to provide propagation through the SWS. The PASOTRON E-gun has produced beams with voltages of up to 220 kV and currents in excess of 1 kA for pulse lengths of over 100 [mu]sec. The PASOTRON HPM source normally operates in the TM[sub 01] mode, and a unique mode converter has been developed to efficiently produce a TE[sub 11] output mode with fixed polarization. The PASOTRON also has the ability to directly produce TE-mode radiation with a rotating output polarization. PASOTRON HPM sources have operated in L, S, C and X-bands, and have produced output powers in the 1 to 5 MW range in C-band at about 20% efficiency with pulse lengths of over 100 [mu]sec.

Goebel, D.M.; Butler, J.M.; Schumacher, R.W.; Santoru, J. (Hughes Research Labs., Malibu, CA (United States)); Eisenhart, R.L. (Hughes Missile Systems Group, Canoga Park, CA (United States))

1994-10-01

314

The Resonance Absorption of Wave Energy in a Dusty Plasma  

NASA Astrophysics Data System (ADS)

Dust particles in plasmas can be highly charged, and can carry a significant proportion of the negative charge of the plasma. Both laboratory and space dusty plasmas can be highly structured, with large density and magnetic field gradients. In such systems, wave energy can be efficiently absorbed at the Alfvén resonance. The modification of the Alfvén resonance absorption mechanism due to dust grains is considered here, and it is shown that waves can be very efficiently absorbed at the Alfvén resonance in a dusty plasma, although it is shown that there is a range of frequencies above the dust cyclotron frequency where resonance damping will not occur due to the presence of mobile dust. The wave that is damped by the resonance absorption can be launched by an external source, or it may be a surface wave localized on the density gradient. In the absence of collisional dissipation processes, the wave mode converts at the resonance into a short wavelength partly electrostatic mode, such as the kinetic Alfvén wave modified by dust. The subsequent damping of this mode by the dust charging process is considered, and the resulting heating of the ions, electrons and dust grains is calculated. The Alfvén resonance absorption process can be important for the process of heating of astrophysical molecular clouds containing dust during the star formation process.

Cramer, N. F.; Vladimirov, S. V.

1997-11-01

315

Opportunities for shear energy scaling in bulk acoustic wave resonators.  

PubMed

An important energy loss contribution in bulk acoustic wave resonators is formed by so-called shear waves, which are transversal waves that propagate vertically through the devices with a horizontal motion. In this work, we report for the first time scaling of the shear-confined spots, i.e., spots containing a high concentration of shear wave displacement, controlled by the frame region width at the edge of the resonator. We also demonstrate a novel methodology to arrive at an optimum frame region width for spurious mode suppression and shear wave confinement. This methodology makes use of dispersion curves obtained from finite-element method (FEM) eigenfrequency simulations for arriving at an optimum frame region width. The frame region optimization is demonstrated for solidly mounted resonators employing several shear wave optimized reflector stacks. Finally, the FEM simulation results are compared with measurements for resonators with Ta2O5/ SiO2 stacks showing suppression of the spurious modes. PMID:25265180

Jose, Sumy; Hueting, Raymond J E

2014-10-01

316

MAGNETOACOUSTIC WAVE ENERGY FROM NUMERICAL SIMULATIONS OF AN OBSERVED SUNSPOT UMBRA  

SciTech Connect

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

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

2011-07-01

317

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

NASA Astrophysics Data System (ADS)

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

Murakami, Tengen; Imai, Yasutaka; Nagata, Shuichi

2014-10-01

318

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

SciTech Connect

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

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

2014-09-01

319

Fractal ladder models and power law wave equations.  

PubMed

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

Kelly, James F; McGough, Robert J

2009-10-01

320

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. PMID:19813816

Kelly, James F.; McGough, Robert J.

2009-01-01

321

Experimental Wave Tank Test for Reference Model 3 Floating-Point Absorber Wave Energy Converter Project  

SciTech Connect

The U.S. Department of Energy established a reference model project to benchmark a set of marine and hydrokinetic technologies including current (tidal, open-ocean, and river) turbines and wave energy converters. The objectives of the project were to first evaluate the status of these technologies and their readiness for commercial applications. Second, to evaluate the potential cost of energy and identify cost-reduction pathways and areas where additional research could be best applied to accelerate technology development to market readiness.

Yu, Y. H.; Lawson, M.; Li, Y.; Previsic, M.; Epler, J.; Lou, J.

2015-01-01

322

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

323

Integrated power clock generators for low energy logic  

Microsoft Academic Search

Low-energy (adiabatic) logic families have been proposed to reduce energy consumption of VLSI logic devices. Instead of the conventional DC power supply, these logic families require AC power supplies (power clocks) that allow energy recovery and also serve as timing clocks for the logic. In this paper, high-frequency resonant DC\\/AC inverters are proposed as power clock generators where all power

D. Maksimovic; V. G. Oklobdzija

1995-01-01

324

Tensor analyzing power standard from the low energy d+T reaction  

NASA Astrophysics Data System (ADS)

The R-matrix analysis of n+? scattering- and d+T reaction-database has been performed for energies below the 4He-breakup treshold. The contribution of partial waves up to orbital momenta l=2 in the d+T channel was quantitatively parametrized. The calculated tensor analyzing power A zz based on resulted R-matrix parameters deviates significantly from pure S-wave form A zz = gP 2(?), still assumed to be acceptable at energies below 200 keV. The deviation has been expressed through the function g(?, E d ), which was found to overestimate polarization standards g from LASL experiment (relative error ? of 0.003 to 0.006) by 3?. It proves S-wave approach to extract g from LASL data as less relevant. Calculated curves g(?, E d ) present the current knowledge of the tensor analyzing power standard.

Vercimak, P.; Simeckova, E.; Bem, P.

2000-01-01

325

Optimization Decomposition of Resistive Power Networks with Energy Storage  

E-print Network

is the integration of power flow control in the power grid network together with the distributed renewable energy integration? With energy storage, there is a possibility to generate more energy when the demand is low sources and energy storage at the endpoints of the network. Renewable energy is intermittent and difficult

Tan, Chee Wei

326

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

E-print Network

development along Oregon's coast, and ii) develop a general conceptual framework of physical and biological these interactions? 4) Can we prioritize important ecological issues (e.g., key interactions)? 5) What studies Shores Conservation Coalition; Maurice Hill, Mineral Management Service; Justin Klure, Oregon Wave Energy

Wright, Dawn Jeannine

327

Output power of piezoelectric MEMS vibration energy harvesters under random oscillations  

NASA Astrophysics Data System (ADS)

Environmental vibrations include random oscillations of different frequencies and amplitudes. Energy harvesters recover the energy associated with these vibrations. Properties of the vibrations and output power are characterized for cantilever-type piezoelectric vibration energy harvesters using (100)-orientated BiFeO3 films subject to both ideal and random oscillations. The displacement and output power under random oscillations were smaller than those under ideal oscillations. This decrease originates with the decreasing acceleration of the fundamental wave with the spurious component having little influence on the resonance response.

Kariya, K.; Yoshimura, T.; Murakami, S.; Fujimura, N.

2014-11-01

328

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

329

Energy eigenstates of magnetostatic waves and oscillations.  

PubMed

Effect of excitation of magnetostatic oscillations in a ferrite resonator by the microwave magnetic field was a subject of many publications of more than the last 40 years. The most interesting multiresonance spectrum of absorption peaks one can observe experimentally is a case of disk-form small ferrite resonators. It is shown in this paper that such small ferrite resonators can be considered as "artificial molecular structures" with properties characterized by energy eigenstates of magnetostatic oscillations. A special interest in these properties may be found in the field of microwave artificial composite materials. PMID:11415247

Kamenetskii, E O

2001-06-01

330

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

331

A Skin-attachable Flexible Piezoelectric Pulse Wave Energy Harvester  

NASA Astrophysics Data System (ADS)

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

Yoon, Sunghyun; Cho, Young-Ho

2014-11-01

332

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

Microsoft Academic Search

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

Z. Chen; Y. Hu

2004-01-01

333

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

334

On The Relationship Between Cross L-shell Pc5 ULF Wave Power and Relativistic Electron Flux Enhancements In The Outer Radiation Belt  

Microsoft Academic Search

Recent research has highlighted the possibility that large-amplitude ULF pulsations may act as an acceleration mechanism for generating relativistic electron populations in the outer zone magnetosphere. We examine solar wind characteristics, Pc5 ULF wave power and outer magnetospheric measurements of high energy electron flux dur- ing the recurrent fast solar wind speed streams which occurred during the first half of

I. R. Mann; R. A. Mathie; R. H. A. Iles; A. N. Fazakerley

2002-01-01

335

Energy-momentum relation for solitary waves of nonlinear Dirac equations  

E-print Network

Solitary waves of nonlinear Dirac, Maxwell-Dirac and Klein-Gordon-Dirac equations are considered. We prove that the energy-momentum relation for solitary waves coincides with the Einstein energy-momentum relation for point particles.

T. V. Dudnikova

2014-04-28

336

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

SciTech Connect

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

Di Bella, Francis A

2014-09-29

337

Microwave power coupling in a surface wave excited plasma  

NASA Astrophysics Data System (ADS)

In recent decades, different types of plasma sources have been used for various types of plasma processing, such as, etching and thin film deposition. The critical parameter for effective plasma processing is high plasma density. One type of high density plasma source is Microwave sheath-Voltage combination Plasma (MVP). In the present investigation, a better design of MVP source is reported, in which over-dense plasma is generated for low input microwave powers. The results indicate that the length of plasma column increases significantly with increase in input microwave power.

Kar, Satyananda; Alberts, Lukas; Kousaka, Hiroyuki

2015-01-01

338

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

NASA Astrophysics Data System (ADS)

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

Sarris, T. E.

2014-07-01

339

Forced wave propagation and energy distribution in anisotropic laminate composites.  

PubMed

Elastodynamic response of anisotropic laminate composite structures subjected to a force loading is evaluated based on the integral representations in terms of Green's matrices. Explicit and asymptotic expressions for guided waves generated by a given source are then obtained from those integrals by means of series expansions and the residue technique. Unlike to conventional modal expansions, such representations keep information about the source, giving an opportunity for a quantitative near- and far-field analysis of generated waves. An effective computer implementation is achieved by the use of fast and stable algorithms for the Green matrix, pole, and residue calculations. The potential of the model is demonstrated by examples of anisotropy manifestation in the directivity of radiated waves. The effect of main energy outflow in the direction of either upper- or inner-ply orientation depending on the source size and frequency is discussed. PMID:21568395

Glushkov, Evgeny; Glushkova, Natalia; Eremin, Artem

2011-05-01

340

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. PMID:22745740

Chen, Yun; Huang, Wei; Constantini, Shlomi

2012-01-01

341

High power, high efficiency 32 GHz space traveling wave tube  

Microsoft Academic Search

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

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

2004-01-01

342

Microscale anechoic architecture: acoustic diffusers for ultra low power microparticle separation via traveling surface acoustic waves.  

PubMed

We present a versatile and very low-power traveling SAW microfluidic sorting device able to displace and separate particles of different diameter in aqueous suspension; the travelling wave propagates through the fluid bulk and diffuses via a Schröder diffuser, adapted from its typical use in concert hall acoustics to be the smallest such diffuser to be suitable for microfluidics. The effective operating power range is two to three orders of magnitude less than current SAW devices, uniquely eliminating the need for amplifiers, and by using traveling waves to impart forces directly upon suspended microparticles, they can be separated by size. PMID:25343424

Behrens, Jan; Langelier, Sean; Rezk, Amgad R; Lindner, Gerhard; Yeo, Leslie Y; Friend, James R

2015-01-01

343

Radiant Energy Power Source for Jet Aircraft  

SciTech Connect

This report beings with a historical overview on the origin and early beginnings of Radiant Energy Power Source for Jet Aircraft. The report reviews the work done in Phase I (Grant DE-FG01-82CE-15144) and then gives a discussion of Phase II (Grant DE-FG01-86CE-15301). Included is a reasonably detailed discussion of photovoltaic cells and the research and development needed in this area. The report closes with a historical perspective and summary related to situations historically encountered on projects of this nature. 15 refs.

Doellner, O.L.

1992-02-01

344

On The Relationship Between Cross L-shell Pc5 ULF Wave Power and Relativistic Electron Flux Enhancements In The Outer Radiation Belt  

NASA Astrophysics Data System (ADS)

Recent research has highlighted the possibility that large-amplitude ULF pulsations may act as an acceleration mechanism for generating relativistic electron populations in the outer zone magnetosphere. We examine solar wind characteristics, Pc5 ULF wave power and outer magnetospheric measurements of high energy electron flux dur- ing the recurrent fast solar wind speed streams which occurred during the first half of 1995. We find a close correlation between extended intervals of significant pulsation power and GOES7 observations of enhanced relativistic (> 2 MeV) electron flux in the outer zone magnetosphere, suggesting that these two features may be causally re- lated. We demonstrate that significant electron flux increases at geosynchronous orbit are only observed in response to ULF wave power which is sustained at high lev- els over a number of days following storm onset. Further, using data from the STRV microsatellites, we examine the evolution of cross L-shell ULF wave power and rel- ativistic (> 750 keV) electron flux from L = 3.75 to L = 6.79. We find that for specific events, the fluxes in these fixed energy detectors can rise across the whole of this L-shell range. In contrast, ULF wave power increases with increasing L-shell, and is typically an order of magnitude higher at L = 6.6 than at L = 4. Our obser- vations suggest that ULF pulsations may play a role in the acceleration mechanism for generating MeV energy "killer" electrons in the magnetosphere, particularly at geosyncronous orbit. Further research should examine in detail the relationship be- tween ULF wave power and MeV energy electron flux rises in the heart of the outer radiation belts around L 4.

Mann, I. R.; Mathie, R. A.; Iles, R. H. A.; Fazakerley, A. N.

345

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

PubMed

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

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

2014-11-01

346

Model-predicted distribution of wind-induced internal wave energy in the world's oceans  

E-print Network

Model-predicted distribution of wind-induced internal wave energy in the world's oceans Naoki-induced internal wave energy in the world's oceans, J. Geophys. Res., 113, C09034, doi:10.1029/2008JC004768. 1 9 July 2008; published 30 September 2008. [1] The distribution of wind-induced internal wave energy

Miami, University of

347

On The Implications of Atmospheric Gravity Waves on Wind Power   

E-print Network

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

Norris, Luke

2011-11-24

348

Power Management, Energy Conversion and Energy Scavenging for Smart Systems  

Microsoft Academic Search

An integral part of the vision for ambient intelligence is the use of large numbers of wireless sensors in a “deploy and forget”\\u000a manner. The long term provision of energy to wireless sensor nodes poses a challenge to this vision. Today the provision of\\u000a power is almost exclusively by means of batteries. The trend in battery technology has been towards

Terence O’Donnell; Wensi Wang

349

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

350

Electric power transmission for a Hanford Nuclear Energy Center (HNEC)  

Microsoft Academic Search

A study of nuclear energy centers was conducted by the Atomic Energy Commission and reported in WASH 1288, Evaluation of Nuclear Energy Centers, January 1974. The portion of the study covering a Hanford Nuclear Energy Center (HNEC) was conducted by Battelle-Northwest, and a preliminary study of transmission of HNEC power was prepared with the assistance of the Bonneville Power Administration

R. L. Richardson; W. J. Dowis

1978-01-01

351

Wind Powering America: Clean Energy for the 21st Century  

SciTech Connect

Wind Powering America Clean Energy for the 21st Century provides basic information about the benefits of wind power, contacts for information about wind power, and a brief description of the Wind Powering America Program, it goals, and its benefits. In addition, the brochure contains perspectives on the benefits of wind power from 10 U.S. citizens from different sectors of society including, farming, ranching, government, education, and the energy industry.

Not Available

2002-10-01

352

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

353

Zero-energy wave packets that follow classical orbits  

NASA Astrophysics Data System (ADS)

Coherent states for a large class of the Lenz-Demkov-Ostrovsky (LDO) potentials are constructed as superpositions of zero-energy Hamiltonian eigenstates. They represent very well-localized stationary wave packets. Moreover, it is shown how to make the packets move along suitable classical orbits. The calculations are performed for a few members of the LDO family of potentials, among them, for the Maxwell's fish-eye model and that used for a theoretical explanation of the periodic system of elements.

Makowski, Adam J.; Pep?owski, Piotr

2012-10-01

354

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

Microsoft Academic Search

We report the measurement of small losses in transmission line (TL) components intended for high-power millimeter-wave applications.\\u000a Measurements were made using two different low-power techniques: a coherent technique using a vector network analyzer (VNA)\\u000a and an incoherent technique using a radiometer. The measured loss in a 140 GHz 12.7 mm diameter TL system, consisting of 1.7 m\\u000a of circular corrugated waveguide and three

S. T. Han; E. N. Comfoltey; Michael Shapiro; Jagadishwar R. Sirigiri; David Tax; Richard J Temkin; P. P. Woskov; D. A. Rasmussen

2008-01-01

355

Evidence of local power deposition and electron heating by a standing electromagnetic wave in electron-cyclotron-resonance plasma  

NASA Astrophysics Data System (ADS)

Microwave plasmas excited at electron-cyclotron resonance were studied in the 0.5-15 mTorr pressure range. In contrast with low-limit pressure conditions where the plasma emission highlights a fairly homogeneous spatial structure, a periodic spatial modulation (period ˜6.2 cm) appeared as pressure increased. This feature is ascribed to a local power deposition (related to the electron density) due to the presence of a standing electromagnetic wave created by the feed electromagnetic field (2.45 GHz) in the cavity formed by the reactor walls. Analysis of the electron energy probability function by Langmuir probe and optical emission spectroscopy further revealed the presence of a high-energy tail that showed strong periodic spatial modulation at higher pressure. The spatial evolution of the electron density and of the characteristic temperature of these high-energy electrons coincides with the nodes (maximum) and antinodes (minimum) of the standing wave. These spatially-modulated power deposition and electron heating mechanisms are then discussed.

Durocher-Jean, A.; Stafford, L.; Dap, S.; Makasheva, K.; Clergereaux, R.

2014-09-01

356

Energy Drinks and Food Bars: Power or Hype?  

MedlinePLUS

... News Anxiety Disorders Relaxation Exercises The Flu Vaccine Energy Drinks and Food Bars: Power or Hype? KidsHealth > ... Downsides Cutting Through the Hype The Buzz on Energy Foods Energy drinks and nutrition bars often make ...

357

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

Microsoft Academic Search

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

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

2002-01-01

358

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

SciTech Connect

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

Thomassen, K.I.

1987-01-01

359

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

E-print Network

development and launch costs. 3) Early revenue growth with a few satellites and participating plants millimeter wave or laser wavelengths. The progression from frequency to system business case is laid out on Earth. This phase enables renewable power plants to be built at remote locations, and yet exploit

360

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

E-print Network

We point out three correlated predictions of the axion monodromy inflation model: large amplitude of gravitational waves, suppression of power on horizon scales and on scales relevant for the formation of dwarf galaxies. While these predictions are likely generic to models with oscillations in the inflaton potential, the axion monodromy model naturally accommodates the required running spectral index through Planck-scale corrections to the inflaton potential. Applying this model to a combined data set of Planck, ACT, SPT, and WMAP low-$\\ell$ polarization cosmic microwave background (CMB) data, we find a best-fit tensor-to-scalar ratio $r_{0.05} = 0.07^{+0.05}_{-0.04}$ due to gravitational waves, which may have been observed by the BICEP2 experiment. Despite the contribution of gravitational waves, the total power on large scales (CMB power spectrum at low multipoles) is lower than the standard $\\Lambda$CDM cosmology with a power-law spectrum of initial perturbations and no gravitational waves, thus mitigating...

Minor, Quinn E

2014-01-01

361

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

E-print Network

Jupiter's Tropospheric Thermal Emission II: Power Spectrum Analysis and Wave Search Joseph, Jupiter jovian planets, Atmosphere clouds, Jupiter jupiter, atmosphere, Dynamics infrared observations, Jupiter Revision 3.2: 16:31 19 June 1996 1 Harrington et al. #12; Proposed running heads: Left: Harrington

Harrington, Joe

362

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

Microsoft Academic Search

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

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

2008-01-01

363

Bringing Robustness and Power Efficiency to Autonomous Energy Harvesting Microsystems  

Microsoft Academic Search

Autonomous devices that are self-powered by extracting their energy from their environment are a new opportunity for monitoring purposes. A multi-energy sources and multi-sensors microsystem targeting autonomous wireless sensor node applications is presented. Since the available energy is not constant over time and due to very low harvested power levels, an efficient energy and power management strategy is mandatory. In

J. F. Christmann; E. Beigne?; C. Condemine; N. Leblond; P. Vivet; G. Waltisperger; J. Willemin

2010-01-01

364

Electrostatic electron cyclotron waves generated by low-energy electron beams  

E-print Network

Electrostatic electron cyclotron waves generated by low-energy electron beams J. D. Menietti, O; KEYWORDS: electrostatic electron waves, plasma waves, beam mode Citation: Menietti, J. D., O. Santolik, J. D. Scudder, J. S. Pickett, and D. A. Gurnett, Electrostatic electron cyclotron waves generated

Santolik, Ondrej

365

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

E-print Network

Estimating Internal Wave Energy Fluxes in the Ocean JONATHAN D. NASH College of Oceanic internal wave generation, propagation, and dissipation. In this paper, the estimation of internal wave. Sampling must be sufficient in depth to allow for the estimation of the internal wave­induced pressure

Kurapov, Alexander

366

Nonhydrostatic and nonlinear contributions to the energy flux budget in nonlinear internal waves  

E-print Network

Nonhydrostatic and nonlinear contributions to the energy flux budget in nonlinear internal waves S and evolution of nonlinear internal waves formed as a result of the interaction of a first-mode internal wave are significant in these large nonlinear internal waves, consistent with recent field observations. Citation

Fringer, Oliver B.

367

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

E-print Network

SEPTEMBER 2006 MOUM ET. AL. 1 Energy Transport by Nonlinear Internal Waves J. N. MOUM1 , J. M which nonlinear internal waves propagate. Shipboard profiling and bottom lander observations capture disturbances that exhibit properties of internal solitary waves, bores and gravity currents. Wave-like pulses

368

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

E-print Network

APRIL 2006 MOUM ET. AL. 1 Energy Transport by Nonlinear Internal Waves J. N. MOUM1 , J. M. KLYMAK2 internal waves propagate. Shipboard profiling and bottom lander observations capture disturbances that exhibit properties of internal solitary waves, bores and gravity currents. Wave-like pulses are highly

369

Power electronics applications in wind energy conversion system: A review  

Microsoft Academic Search

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

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

2010-01-01

370

Optimal Power Cost Management Using Stored Energy in Data Centers  

E-print Network

that arise by the use of uninterrupted power supply (UPS) units as energy storage devices. This rep- resentsOptimal Power Cost Management Using Stored Energy in Data Centers Rahul Urgaonkar, Bhuvan Urgaonkar as the storage capacity is increased. Our work opens up a new area in data center power management. Categories

Urgaonkar, Bhuvan

371

Optimal Power Cost Management Using Stored Energy in Data Centers  

E-print Network

of uninterrupted power supply (UPS) units as energy storage devices. This rep- resents a deviation from the usualOptimal Power Cost Management Using Stored Energy in Data Centers Rahul Urgaonkar, Bhuvan Urgaonkar work opens up a new area in data center power management. Categories and Subject Descriptors C.4

Neely, Michael J.

372

Technical options for high average power free electron milimeter-wave and laser devices  

NASA Technical Reports Server (NTRS)

Many of the potential space power beaming applications require the generation of directed energy beams with respectable amounts of average power (MWs). A tutorial summary is provided here on recent advances in the laboratory aimed at producing direct conversion of electrical energy to electromagnetic radiation over a wide spectral regime from microwaves to the ultraviolet.

Swingle, James C.

1989-01-01

373

Power and Energy Management for Server Systems Ricardo Bianchini  

E-print Network

into large and expensive uninterruptible power supplies and backup power generators, both of whichPower and Energy Management for Server Systems Ricardo Bianchini and Ram Rajamony Department of Computer Science Low-Power Computing Research Center Rutgers University IBM Austin Research Lab Piscataway

Bianchini, Ricardo

374

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

E-print Network

in such a way that the power ca hydro-pneumatic storage as in the Pelamis, for example. Furthermore, the controlEnergy Storage System Sizing for Smoothing Power Generation of Direct J. Aubry1 , P. Bydlowski 1 E as the SEAREV. The ESS is to insure a smoothed output power profile. First, the output set point power

Boyer, Edmond

375

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

SciTech Connect

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

Ikeno, Masaaki; Kajima, Ryoichi; Matsuyama, Masafumi; Sakakiyama, Tsutomu [Central Research Inst. of Electric Power Industry, Abiko (Japan)

1995-12-31

376

Efficient Energy Harvesting With Electromagnetic Energy Transducers Using Active Low-Voltage Rectification and Maximum Power Point Tracking  

Microsoft Academic Search

This paper reports on efficient interfacing of typical vibration-driven electromagnetic transducers for micro energy harvesting. For this reason, an adaptive charge pump for dynamic maximum power point tracking is compared with a novel active full-wave rectifier design. For efficient ultra-low voltage rectification, the introduced active diode design uses a common-gate stage in conjunction with supply-independent biasing. While this active rectifier

Dominic Maurath; Philipp F. Becker; Dirk Spreemann; Yiannos Manoli

2012-01-01

377

Super-radiant backward-wave oscillators with enhanced power conversion  

SciTech Connect

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

Rostov, V. V. [Institute of High Current Electronics, Siberian Branch of Russian Academy of Science, Tomsk (Russian Federation); Savilov, A. V. [Institute of Applied Physics, Russian Academy of Sciences, Nizhny Novgorod, Russia, and Lobachevsky State University of Nizhny Novgorod (Russian Federation)

2013-02-15

378

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

E-print Network

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

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

2014-01-01

379

Interaction of waves, currents and tides, and wave-energy impact on the beach area of Sylt Island  

NASA Astrophysics Data System (ADS)

Erosion due to waves is an important and actual problem for most coastal areas of the North Sea. The objective of this study was to estimate the impact of wave action on the coastline of Sylt Island. From a 2-year time series (November 1999 to October 2001) of hydrological and wave parameters generated with a coupled wave-current modelling system, a period comprising storm ‘Anatol’ (3-4 December 1999) is used to investigate the effects of waves on currents and water levels and the input of wave energy into the coastline. The wave-induced stress causes an increase of the current velocity of 1 m/s over sand and an additional drift along the coast of about 20 cm/s. This produces a water level increase of more than 20 cm in parts of the tidal basin. The model system also calculates the wave energy input into the coastline. Scenario runs for December 1999 with a water level increase of 50 cm and wind velocity increased by 10% show that the input of the wave energy into the west coast of Sylt Island increases by 30% compared to present conditions. With regard to the forecasted near-future (Woth et al., Ocean Dyn 56:3-15, 2006) increase of strong storm surges, the scenario results indicate an increased risk of coastal erosion in the surf zone of Sylt Island.

Pleskachevsky, Andrey; Eppel, Dieter P.; Kapitza, Hartmut

2009-06-01

380

An Ultra-Low-Power Power Management IC for Energy-Scavenged Wireless Sensor Nodes  

E-print Network

925 An Ultra-Low-Power Power Management IC for Energy-Scavenged Wireless Sensor Nodes Michael D less power and are becoming smaller as this technology matures. Scavenged- power sensor nodes are now a reality with modern processor, sensor and radio technology [1], [2]. The efficiency of the scavenger

Sanders, Seth

381

Holocene reef development where wave energy reduces accommodation  

USGS Publications Warehouse

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

Grossman, Eric E.; Fletcher, Charles H.

2004-01-01

382

Wing Wave: Feasible, Alternative, Renewable, Electrical Energy Producing Ocean Floor System  

E-print Network

Wing Wave: Feasible, Alternative, Renewable, Electrical Energy Producing Ocean Floor System Mark Florida Institute of Technology Melbourne, Florida, USA swood@fit.edu Abstract--Wing-Wave is an ocean, alternative energy system to convert the circular motion of ocean waves as they propagate through the sea

Wood, Stephen L.

383

Propagation-invariant wave fields with finite energy.  

PubMed

Propagation invariance is extended in the paraxial regime, leading to a generalized self-imaging effect. These wave fields are characterized by a finite number of transverse self-images that appear, in general, at different orientations and scales. They possess finite energy and thus can be accurately generated. Necessary and sufficient conditions are derived, and they are appropriately represented in the Gauss-Laguerre modal plane. Relations with the following phenomena are investigated: classical self-imaging, rotating beams, eigen-Fourier functions, and the recently introduced generalized propagation-invariant wave fields. In the paraxial regime they are all included within the generalized self-imaging effect that is presented. In this context we show an important relation between paraxial Bessel beams and Gauss-Laguerre beams. PMID:10680631

Piestun, R; Schechner, Y Y; Shamir, J

2000-02-01

384

Hydrogen storage of energy for small power supply systems  

E-print Network

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

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

2005-01-01

385

Networking Low-Power Energy Harvesting Devices: Measurements and Algorithms  

E-print Network

--Recent advances in energy harvesting materials and ultra-low-power communications will soon enable the realization types (rechargeable battery and a capacitor) require different algorithms. We develop algorithms energy inputs are stochastic. Index Terms--Energy harvesting, ultra-low-power networking, indoor radiant

Shepard, Kenneth

386

A novel uninterruptible power supply using flywheel energy storage unit  

Microsoft Academic Search

A novel uninterruptible power supply (UPS) with a flywheel energy storage unit is presented. The UPS is composed of an AC\\/DC rectifier, a DC\\/AC inverter, a permanent magnet brushless DC motor, a motor converter and a flywheel energy storage unit. Firstly, main power circuit of the UPS and its flywheel energy storage unit are introduced. Then the control strategies of

Chen Junling; Jiang Xinjian; Zhu Dongqi; Wei Haigang

2004-01-01

387

Solar energy at Forest Research Solar Power at Alice Holt  

E-print Network

Solar energy at Forest Research Solar Power at Alice Holt research station provides a renewable source of energy reducing reliance on power from the national grid Forest Research, an agency per annum. As part of a programme to improve energy efficiency and meet government targets on carbon

388

Designing and Managing Datacenters Powered by Renewable Energy  

E-print Network

Designing and Managing Datacenters Powered by Renewable Energy ´I~nigo Goiri, William Katsak, Kien,wkatsak,lekien,tdnguyen,ricardob}@cs.rutgers.edu Abstract On-site renewable energy has the potential to reduce data- centers' carbon footprint and power. These datacenters will either generate their own renewable energy (self-generation) or draw it directly from

389

Stopping power of mammalian cells for low energy ions  

Microsoft Academic Search

This work investigates the stopping power of V79 cells for low energy ions. An energy equation for the incident ion, E, has been constructed in order to establish the stopping powers of mammalian cell for low energy ion implantation. Based on the biological structure of the mammalian cell, a physical structural model is proposed in which the attached cell is

Ding Kejian; Yang Xiaolin; Feng Huiyun; Hu Zhiwen; Zhan Furu; Wu Lijun; Wu Yuejin; Kong Mingguang; Zhu Xiaoguang; Yu Zengliang

2007-01-01

390

Throughput of wireless networks powered by energy harvesting  

Microsoft Academic Search

Designing mobile devices for harvesting ambient energy such as kinetic activities or electromagnetic radiation (EMR) will enable mobile networks to self sustain besides alleviate global warming. The throughput of a mobile ad hoc network powered by energy harvesting is analyzed in this paper using a stochastic-geometry approach. The transmitters powered by energy harvesting are modeled as a Poisson point process

Kaibin Huang

2011-01-01

391

Cost-effective wind energy utilization for reliable power supply  

Microsoft Academic Search

Environmental concerns and fuel cost uncertainties associated with the use of conventional energy sources have resulted in rapid growth of wind energy applications in power generating systems. It is important to assess the actual cost and benefit of utilizing wind energy in a power system. Such assessments require realistic cost\\/reliability evaluation methods and quantitative indices. This paper presents a simulation

Rajesh Karki; Roy Billinton

2004-01-01

392

Progress on single barrier varactors for submillimeter wave power generation  

NASA Technical Reports Server (NTRS)

Theoretical work on Single Barrier Varactor (SBV) diodes, indicate that the efficiency for a multiplier has a maximum for a considerably smaller capacitance variation than previously thought. The theoretical calculations are performed, both with a simple theoretical model and a complete computer simulation using the method of harmonic balance. Modeling of the SBV is carried out in two steps. First, the semiconductor transport equations are solved simultaneously using a finite difference scheme in one dimension. Secondly, the calculated I-V, and C-V characteristics are input to a multiplier simulator which calculates the optimum impedances, and output powers at the frequencies of interest. Multiple barrier varactors can also be modeled in this way. Several examples on how to design the semiconductor layers to obtain certain characteristics are given. The calculated conversion efficiencies of the modeled structures, in a multiplier circuit, are also presented. Computer simulations for a case study of a 750 GHz multiplier show that InAs diodes perform favorably compared to GaAs diodes. InAs and InGaAs SBV diodes have been fabricated and their current vs. voltage characteristics are presented. In the InAs diode, was the large bandgap semiconductor AlSb used as barrier. The InGaAs diode was grown lattice matched to an InP substrate with InAlAs as a barrier material. The current density is greatly reduced for these two material combinations, compared to that of GaAs/AlGaAs SBV diodes. GaAs based diodes can be biased to higher voltages than InAs diodes.

Nilsen, Svein M.; Groenqvist, Hans; Hjelmgren, Hans; Rydberg, Anders; Kollberg, Erik L.

1992-01-01

393

Waveguide Power Combiner Demonstration for Multiple High Power Millimeter Wave TWTAs  

NASA Technical Reports Server (NTRS)

NASA is presently developing nuclear reactor technologies, under Project Prometheus, which will provide spacecraft with greatly increased levels of sustained onboard power and thereby dramatically enhance the capability for future deep space exploration. The first mission planned for use of this high power technology is the Jupiter Icy Moons Orbiter (JIMO). In addition to electric propulsion and science, there will also be unprecedented onboard power available for deep space communications. A 32 GHz transmitter with 1 kW of RF output power is being considered to enable the required very high data transmission rates. One approach to achieving the 1 kW RF power, now being investigated at NASA GRC, is the possible power combining of a number of 100-1 50 W TWTs now under development. The work presented here is the results of a proof-of-concept demonstration of the power combining Ka-band waveguide circuit design and test procedure using two Ka- band TWTAs (Varian model VZA6902V3 and Logimetrics model A440/KA-1066), both of which were previously employed in data uplink evaluation terminals at 29.36 GHz for the NASA Advanced Communications Technology Satellite (ACTS) program. The characterization of the individual TWTAs and power combining demonstration were done over a 500 MHz bandwidth from 29.1 to 29.6 GHz to simulate the Deep Space Network (DSN) bandwidth of 3 1.8 to 32.3 GHz. Figures 1-3 show some of the power transfer and gain measurements of the TWTAs using a swept signal generator (Agilent 83640b) for the RF input. The input and output powers were corrected for circuit insertion losses due to the waveguide components. The RF saturated powers of both ACTS TWTAs were on the order of 120 W, which is comparable to the expected output powers of the 32 GHz TWTs. Additional results for the individual TWTAs will be presented (AM/AM, AM/PM conversion and gain compression), some of which were obtained from swept frequency and power measurements using a vector network analyzer. The results for the power combining demonstration as well as a more detailed description of the power combining test circuit and test procedure will also be presented.

Wintucky, Edwin G.; Simons, Rainee N.; Lesny, Gary G.; Glass, Jeffrey L.

2004-01-01

394

Energy: Add Power to Your Collection.  

ERIC Educational Resources Information Center

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

Rholes, Julia M.

1981-01-01

395

Wave energy utilization into ship propulsion by fins attached to a ship  

SciTech Connect

Resistance of a ship increases in waves, that is, so called resistance increase of a ship due to waves. However, an oscillatory hydrofoil attached to the ship bow generates thrust. Under a certain condition, the ship can be driven by wave power alone. This paper reviews the design and performance of such a system.

Isshiki, H. [Hitachi Zosen Corp., Osaka (Japan)

1994-12-31

396

Ground-based Pc5 ULF wave power: Solar wind speed and MLT dependence  

NASA Astrophysics Data System (ADS)

Using over 20 years of ground-based magnetometer data from the CANOPUS/CARISMA magnetometer array, we present a statistical characterisation of Pc5 ultra-low frequency (ULF) power in the 2-10 mHz band as a function of magnetic local time (MLT), L-shell, and solar wind speed. We examine the power across L-shells between 4.2 and 7.9, using data from the PINA, ISLL, GILL and FCHU stations, and demonstrate that there is a significant MLT dependence in both the H- and D-component median 2-10 mHz power during both fast (>500 km/s) and slow (<500 km/s) solar wind speeds. The H-component power consistently dominates over D-component power at all MLTs and during both fast and slow solar wind. At the higher-L stations (L>5.4), there are strong MLT power peaks in the morning and midnight local time sectors; the morning sector dominating midnight during fast solar wind events. At lower L-shells, there is no evidence of the midnight peak and the 2-10 mHz power is more symmetric with respect to MLT except during the fastest solar wind speeds. There is little evidence in the ground-based power of a localised MLT peak in ULF power at dusk, except at the lowest L-shell station, predominantly in the H-component. The median 2-10 mHz power increases with an approximate power law dependence on solar wind speed, at all local times across the L-shell domain studied in both components. The H-component power peaks at the latitude of the GILL station, with significantly lower power at both higher and lower L-shells. Conversely, the D-component power increases monotonically. We believe that this is evidence for 2-10 mHz power accumulating at auroral latitudes in field line resonances. Finally, we discuss how such ULF wave power characterisation might be used to derive empirical radiation belt radial diffusion coefficients based on, and driven by, the solar wind speed dependence of ULF wave power.

Pahud, D. M.; Rae, I. J.; Mann, I. R.; Murphy, K. R.; Amalraj, V.

2009-07-01

397

Satellite power systems (SPS) energy conversion and power management  

SciTech Connect

Two reference systems are included in the NASA/DOE reference set - gallium arsenide (GaAs) and silicon (Si). Both the GaAs and Si photovoltaic concepts are coplanar and have a single microwave antenna located at the end of the satellite to provide 5 gigawatts (GW) of power at the utility interface. Impacts are reported that would result to the reference concept from these alternatives to microwave conversion, photovoltaic techniques, solar concentration ratio, and power distribution voltage. 3 refs.

Nussberger, A.A.

1981-01-01

398

Demonstration of efficiency enhancement in a high-power backward-wave oscillator by plasma injection  

NASA Astrophysics Data System (ADS)

An experimental demonstration of a strong enhancement of the interaction efficiency in a high-power relativistic backward-wave oscillator when plasma is injected is presented. Controlled plasma injection enhances the interaction efficiency over the vacuum case by a factor of up to 8 to a value of about 40 percent. The enhanced interaction is attributed to induced scattering of the electromagnetic radiation of electrons in an electrostatic field produced by the background plasma and a beam space-charge wave in the corrugated interaction region.

Carmel, Y.; Minami, K.; Kehs, R. A.; Destler, W. W.; Granatstein, V. L.

1989-05-01

399

High extinction ratio and saturation power traveling-wave electroabsorption modulator  

Microsoft Academic Search

An InGaAsP multiquantum-well traveling-wave electroabsorption modulator is demonstrated with high extinction ratio and modulation efficiency. By designing a strain-compensated quantum-well active region with traveling-wave design, high saturation power (>14 dBm) for >20-GHz high-speed performance (1.5 dB drop at 20 GHz) is achieved. Due to high modulation efficiency (>30 dBN for 0 to 1 V 40-dB extinction ratio in 2 V),

Yi-Jen Chiu; Hsu-Feng Chou; Volkan Kaman; Patrick Abraham; John E. Bowers

2002-01-01

400

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

NASA Technical Reports Server (NTRS)

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

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

1992-01-01

401

PARTICLE ENERGY SPECTRA AT TRAVELING INTERPLANETARY SHOCK WAVES  

SciTech Connect

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

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

2012-09-20

402

Bernstein wave in relativistic plasma with arbitrary energy anisotropy  

NASA Astrophysics Data System (ADS)

The Bernstein wave (BW) in a magnetized relativistic plasma is discussed in detail for a particular choice of distribution function1 that permits an exact analytical reduction of the dispersion relation for arbitrary energy anisotropy. The resulting dispersion relation is solved numerically in order to highlight the effect of energy anisotropy and the relativistic effects on the propagation characteristics of BW. The oscillatory character of the Bessel function appears due to the particular choice of the distribution function and thus changes the propagation characteristics significantly for short wavelengths (i.e., perpendicular wavelength is smaller than Larmour radius k?>1 ). However, for longer wavelengths, these characteristics show a trend similar to the Maxwellian distribution. The dispersion relations for the non-relativistic and ultra-relativistic regimes are also obtained. The anisotropy provides a free energy to make the Bernstein wave unstable satisfying the threshold condition due to oscillatory character of the Bessel functions. Our result may prove useful for a wide range of applications e.g., for magnetized relativistic plasma environments such as astrophysical and space plasmas, laboratory plasmas with intense rf heating and for relativistic electron beams used for microwave generation. 1. P. H. Yoon and R.C. Davidson, Phys. Rev. A, 35, 2619 (1987).

Bashir, M.; Hirose, A.; Murtaza, G.; Noreen, N.; Tahir, I.

2012-12-01

403

Particle Energy Spectra at Traveling Interplanetary Shock Waves  

NASA Astrophysics Data System (ADS)

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

Reames, Donald V.

2012-09-01

404

Novel Development of Power Transformation Technology Supporting Electric Power and Energy  

NASA Astrophysics Data System (ADS)

The power transformation technology which is the key point of electric power transmission supports our life base in the electric power energy field. Especially, the static apparatus which is used as the electric power conversion and control has an important role at the substation. In this review, the novel development of power transformation technology supporting electric power and energy is described with the maintenance diagnostic technology of sustainability and safety transformer, condenser and its applied technology for variation of power supply and load under the electric power system, high current technology under the power and electric filed and surge analysis technology at the substation. The power transformation technology and static apparatus have been developed in a high level in our country. The problem in this review will be expected to overcome soon.

Okubo, Kenji; Nishimura, Shoji; Goda, Yutaka; Baba, Yoshihiro

405

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

SciTech Connect

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

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

2014-08-01

406

Unscented Kalman filtering for wave energy converters system identification  

NASA Astrophysics Data System (ADS)

A model for a oscillating flap wave energy converter (WEC) is as a single degree of freedom system with a non-linear term to allow for the drag of the device through the water, known as the Morison term. The focus of this system identification is on estimating the dynamic state of the system and estimating the non-linear parameter from observations of the wave elevation and the vertical displacement of the device. It is assumed that the mass, stiffness and damping of the system, without the Morison term, are known from the physical characteristics of the device. The Kalman Filter (KF) can be used to estimate the states of a linear system, however, it is not directly applicable to a non-linear system. Various adaptations have been proposed for non-linear systems. One of the first was the extended Kalman Filter (EKF) which relied on a linearization about the current state values. However, an alternative approach, known as the unscented Kalman Filter (UKF) has been found to give a better performance and is easier to implement. We apply the UKF to estimate the dynamic states of the system together with the non-linear parameter. The fitted model can be used to predict the performance of the device in different wave environments.

Bakar, Mohd Aftar Abu; Green, David A.; Metcalfe, Andrew V.; Ariff, Noratiqah Mohd

2014-06-01

407

Energy optimization of quantum Monte Carlo wave functions  

NASA Astrophysics Data System (ADS)

In recent years many methods have been proposed for energy optimizing quantum Monte Carlo wave functions. Of these, the three highly efficient methods are: 1) The generalized eigenvalue method of Nightingale and Melik-Alaverdian, which was proposed by them for linear parameters only but extended by us to nonlinear parameters. 2) The effective fluctuation potential (EFP) method of Fahy, Filippi and coworkers, and the recent perturbative EFP of Schautz, Scemama and Filippi. We show that the latter can be more simply derived as first-order perturbation theory in a nonorthogonal basis. 3) The modified Newton method of Umrigar and Filippi and of Sorella. We show that the three methods are related to each other and point out that a control parameter can be employed in each of them to make them totally stable. We use these methods to optimize all the parameters in the Jastrow and the determinantal parts of the wave function and point out that different issues arise in optimizing the Jastrow and the determinantal parameters. By systematically increasing the number of determinants we find that seemingly similar systems, such as C2 and Si2 have vastly different fixed-node errors for single-determinant wave functions.

Umrigar, C. J.; Toulouse, J.

2006-03-01

408

Energy flux of Alfven waves in weakly ionized plasma  

E-print Network

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

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

2008-05-29

409

Plasma diagnostics of low pressure high power impulse magnetron sputtering assisted by electron cyclotron wave resonance plasma  

SciTech Connect

This paper reports on an investigation of the hybrid pulsed sputtering source based on the combination of electron cyclotron wave resonance (ECWR) inductively coupled plasma and high power impulse magnetron sputtering (HiPIMS) of a Ti target. The plasma source, operated in an Ar atmosphere at a very low pressure of 0.03 Pa, provides plasma where the major fraction of sputtered particles is ionized. It was found that ECWR assistance increases the electron temperature during the HiPIMS pulse. The discharge current and electron density can achieve their stable maximum 10 {mu}s after the onset of the HiPIMS pulse. Further, a high concentration of double charged Ti{sup ++} with energies of up to 160 eV was detected. All of these facts were verified experimentally by time-resolved emission spectroscopy, retarding field analyzer measurement, Langmuir probe, and energy-resolved mass spectrometry.

Stranak, Vitezslav [Ernst-Moritz-Arndt-Universitaet Greifswald, Institut fuer Physik, Felix-Hausdorff-Str. 6, 17489 Greifswald (Germany); University of South Bohemia, Institute of Physics and Biophysics, Branisovska 31, 370 05 Ceske Budejovice (Czech Republic); Herrendorf, Ann-Pierra; Drache, Steffen; Bogdanowicz, Robert; Hippler, Rainer [Ernst-Moritz-Arndt-Universitaet Greifswald, Institut fuer Physik, Felix-Hausdorff-Str. 6, 17489 Greifswald (Germany); Cada, Martin; Hubicka, Zdenek [Institute of Physics v. v. i., Academy of Science of the Czech Republic, Na Slovance 2, 182 21 Prague (Czech Republic); Tichy, Milan [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 180 00 Prague (Czech Republic)

2012-11-01

410

Direct conversion of infrared radiant energy for space power applications  

NASA Technical Reports Server (NTRS)

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

Finke, R. C.

1982-01-01

411

Energy harvesting/scavenging for powering (-)sensors Lead: P. Basset.  

E-print Network

Energy harvesting/scavenging for powering (µ-)sensors Lead: P. Basset. Permanent members: F. Marty Scavenger for Autonomous Microsystems (SESAM): The objective is the elaboration of an energy harvester

Baudoin, Geneviève

412

Power and energy reduction via pipeline balancing  

Microsoft Academic Search

Minimizing power dissipation is an important design require- ment for both portable and non-portable systems. In this work, we propose an architectural solution to the power problem that retains performance while reducing power. The technique, known as Pipeline Balancing (PLB), dynamically tunes the resources of a general purpose processor to the needs of the program by mon- itoring performance within

R. Iris Bahar; Srilatha Manne

2001-01-01

413

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

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

414

Ultrafast and low-power terahertz wave modulator based on organic photonic crystal  

NASA Astrophysics Data System (ADS)

We theoretically investigate the modulation efficiency, response time, and pump power of a terahertz-beam intensity modulator by using an organic photonic crystal slab structure with high quality factor "defect" cavity. The basic operation of an ultrafast low-power terahertz wave modulator actuated by the dynamical shifts of the defect mode induced by pump intensity is discussed in detail. The finite-difference time-domain method is used to verify and analyze the characteristics of the terahertz wave modulator. The device exhibited extinction ratio of 47.15 dB and insertion loss of 3.2 dB at frequency of 1.062 THz with ultrafast response times on the order of several picoseconds.

Li, Jiu-sheng; Zouhdi, Said

2012-03-01

415

The renewable energy applications for uninterruptible power supply based on compressed air energy storage system  

Microsoft Academic Search

The objective of this paper is to propose a modeling of the renewable energy applications for uninterruptible power supply (UPS) based on compressed air energy storage system (CAES). The system is composite technology, which composes of energy storage system and electric power supply system. The energy will transfer from the renewable energy resource to the CAES system drives the air

Varin Vongmanee

2009-01-01

416

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

NASA Technical Reports Server (NTRS)

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

Wintucky, Edwin G.

2000-01-01

417

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

NASA Technical Reports Server (NTRS)

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

Jacques, S. A.

1977-01-01

418

Continuous wave 935 nm Nd:CNGG laser at watt-level power.  

PubMed

An efficient continuous wave (CW) laser-diode-pumped Nd-doped Ca(3)(NbGa)(2-x)Ga(3)O(12) (CNGG) laser operating at 935 nm is demonstrated by using a simple linear cavity for the first time to our knowledge. Output power up to 1.12 W is obtained, corresponding to a slope efficiency of 7.1% and an optical-to-optical efficiency of 5.7%. The laser operates with the fundamental transverse mode when the output power is as high as 800 mW. This laser provides a potential light source for differential absorption lidar in water vapor detection. PMID:18246148

Li, Qinan; Feng, Baohua; Wei, Zhiyi; Zhang, Dongxiang; Li, Dehua; Zhang, Zhiguo; Zhang, Huaijin; Wang, Jiyang

2008-02-01

419

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

PubMed

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 input-output relation loses its linearity, becomes multi-valued, and experiences jumps due to large mechanical deformations. The behavior below and above resonance is qualitatively different and is qualitatively material dependent. PMID:19049934

Yang, Zengtao; Yang, Jiashi; Hu, Yuantai

2008-11-01

420

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

SciTech Connect

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

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

2012-07-15

421

Gravitational wave energy spectrum of a parabolic encounter  

SciTech Connect

We derive an analytic expression for the energy spectrum of gravitational waves from a parabolic Keplerian binary by taking the limit of the Peters and Mathews spectrum for eccentric orbits. This demonstrates that the location of the peak of the energy spectrum depends primarily on the orbital periapse rather than the eccentricity. We compare this weak-field result to strong-field calculations and find it is reasonably accurate ({approx}10%) provided that the azimuthal and radial orbital frequencies do not differ by more than {approx}10%. For equatorial orbits in the Kerr spacetime, this corresponds to periapse radii of r{sub p} > or approx. 20M. These results can be used to model radiation bursts from compact objects on highly eccentric orbits about massive black holes in the local Universe, which could be detected by the Laser Interferometer Space Antenna (LISA).

Berry, Christopher P. L.; Gair, Jonathan R. [Institute of Astronomy, Madingley Road, Cambridge, CB3 0HA (United Kingdom)

2010-11-15

422

The RF-powered surface wave sensor oscillator--a successful alternative to passive wireless sensing.  

PubMed

A novel, passive wireless surface acoustic wave (SAW) sensor providing a highly coherent measurand proportional frequency, frequency modulated (FM) with identification (ID) data and immune to interference with multiple-path signals is described. The sensor is appropriate for bandwidth-limited applications requiring high-frequency accuracy. It comprises a low-power oscillator, stabilized with the sensing SAW resonator and powered by the rectified radio frequency (RF) power of the interrogating signal received by an antenna on the sensor part. A few hundred microwatts of direct current (DC) power are enough to power the sensor oscillator and ID modulation circuit and achieve stable operation at 1.0 and 2.49 GHz. Reliable sensor interrogation was achieved over a distance of 0.45 m from a SAW-based interrogation unit providing 50 mW of continuous RF power at 915 MHz. The -30 to -35 dBm of returned sensor power was enough to receive the sensor signal over a long distance and through several walls with a simple superheterodyne FM receiver converting the sensor signal to a low measurand proportional intermediate frequency and retrieving the ID data through FM detection. Different sensor implementations, including continuous and pulsed power versions and the possibility of transmitting data from several measurands with a single sensor, are discussed. PMID:15478976

Avramov, Ivan D

2004-09-01

423

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

NASA Astrophysics Data System (ADS)

An overmoded slow wave type Ka band generator is investigated experimentally to produce high power millimeter waves in this paper. The experiments were carried out at the TORCH-01 accelerator. The produced microwave frequency was measured by dispersive line method, and the power was estimated by integrating over the radiation pattern at far field. With relatively low guiding magnetic field of 0.8 T and diode voltage and beam current of 590 kV and 5.2 kA, respectively, a 33.56 GHz millimeter wave with an output power of 320 MW was generated, and the microwave mode was quasi-TM01 mode.

Zhu, Jun; Shu, Ting; Zhang, Jun; Li, Guolin; Zhang, Zehai; Fan, Yuwei

2011-05-01

424

Symmetric and asymmetric mode interaction in high-power traveling wave amplifier  

NASA Astrophysics Data System (ADS)

High power microwave TWT amplifier operation has been studied for use in electron accelerators. The performance of the amplifiers has been marred, in some cases, by pulse shortening of the microwave signal, possibly due to hybrid HEM11 mode interaction with the beam. In this paper we describe experiments which investigate high power operation and the effects of HEM modes on the amplifier performance. We report the high output powers (>50 MW) with efficient (>54%) amplification of microwaves in an X-band traveling wave amplifier, and present preliminary data showing operation at a few megawatt output levels in Ka band. In some experiments peak power levels in X-band exceeding 120 MW were measured at an efficiency of 47%. The excitation of the asymmetric hybrid electro-magnetic mode was monitored carefully, but does not seem to have a critical impact on the main interaction process in spite of the fact that its dispersion curve almost overlaps that of the symmetric interacting mode. Theoretical analysis of the interaction in a tapered traveling wave structure indicates that, even if the amount of power in the asymmetric modes at the input of the structure is comparable to that in the symmetric mode, the asymmetric modes cause no power reduction in the symmetric mode. For the case of off axis beams the TM01 output power may drop by about 30% and the power in the hybrid mode reach about one third of that in the symmetric mode. In order to avoid hybrid mode excitation it is necessary to suppress the reflections from both ends of the output structure several dB below the gain level of the asymmetric mode.

Wang, Pingshan; Xu, Zhou; Grabowski, Chris.; Nation, John A.; Banna, Samer; Schächter, Levi

2001-05-01

425

Numerical studies of filamentary plasma formation in high power millimeter wave field  

NASA Astrophysics Data System (ADS)

Filamentary structure characterizes millimeter-wave discharge in air and the ionization front propagates at supersonic speed in a high power millimeter-wave, generating a shock wave. In this study, the filamentary structure was studied experimentally and analytically using a 170GHz Gyrotron at the peak intensity range of 50 kW/cm^2 to 200kW/cm^2. On the propagation process of ionization front, it is important to investigate steady plasma formation process in a filamentary form through millimeter wave. Each filamentary element observed in the ionization front propagates not along or perpendicular to the electric field, but obliquely. To solve this mechanism, 2-dimensional numerical analysis was conducted assuming this phenomenon as a plasma fluid model. In dozens of times the size of plasma element scale, the steady plasma structure formation was simulated, and the calculation was compared with previous experimental results. The calculated formation patterns were in good qualitative agreement with experiments. The calculation model provides a physical interpretation of the pattern formation and dynamics. From the interpretation, it was found that accurate ionization model in low electric field is needed for good agreement with experiments. Moreover, for a quantitative agreement, not only the ionization model but also consideration of 3-dimensional effects are necessary, since 2-dimensional simulation cannot estimate accurate wave reflection and interaction by plasma.

Takeichi, Tensei; Yamaguchi, Toshikazu; Fukunari, Masafumi; Koizumi, Hiroyuki; Komurasaki, Kimiya; Arakawa, Yoshihiro

2012-10-01

426

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

DOEpatents

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

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

1993-01-01

427

Energy/Water Sustainability and the Electric Power  

E-print Network

Electric Power Research Institute, Inc. All rights reserved. Water Use Efficiency (steam cycle plantsEnergy/Water Sustainability and the Electric Power Industry Robert Goldstein, Kent Zammit, Chuck Mc April 10, 2009 #12;2© 2009 Electric Power Research Institute, Inc. All rights reserved. Topics · Nature

Keller, Arturo A.

428

FUTURE POWER GRID INITIATIVE Modeling of Distributed Energy  

E-print Network

FUTURE POWER GRID INITIATIVE Modeling of Distributed Energy Resources in the Smart Grid OBJECTIVE of the aggregated models includes the following steps: » modeling of the individual distributed resources (power/C load power consumption for different house types, as a function of the frequency of Tset, (amplitude

429

Status Of The Repetitive High Energy Pulsed Power Project  

Microsoft Academic Search

High average power pulse compression systems are being considered for use in several applications. The Repetitive High Energy Pulsed Power (RHEPP) system will consist of a 7 stage magnetic pulse compressor driving a linear induction voltage adder with an e-beam diode load. It is being designed to deliver 350 kW of average power to the diode in 60 ns FWHM,

H. C. Harjes; K. J. Penn; K. W. Reed; C. R. McClenahan; G. E. Laderach; R. W. Wavrik; J. Adcock; M. Butler; G. A. Mann; L. Martinez; F. A. Morgan; G. J. Weber; E. L. Neau

1991-01-01

430

Energy analysis of coal, fission, and fusion power plants  

Microsoft Academic Search

The method of net energy analysis has been applied to coal, fission, and fusion power plants. Energy consumption over the lifetime of the plants has been calculated for construction, operation and maintenance, fuel, public welfare, and land use and restoration. Thermal and electric energy requirements were obtained separately for each energy consuming sector. The results of the study are presented

N. Tsoulfanidis

1981-01-01

431

Longitudinal Shock Wave Depolarization of Pb(Zr52Ti48)O3 Polycrystalline Ferroelectrics and their Utilization in Explosive Pulsed Power  

NASA Astrophysics Data System (ADS)

A poled lead zirconate titanate Pb(Zr52Ti48)O3 (PZT) polycrystalline piezoelectric ceramic energy-carrying element of a compact explosive-driven power generator was subjected to a longitudinal explosive shock wave (the wave front traveled along the polarization vector P0). The shock compression of the element at pressures of 1.5-3.8 GPa caused almost complete depolarization of the sample. Shock wave velocity in the PZT was determined to be 3.94 ± 0.27 km/s. The electric charge stored in a ferroelectric, due to its remnant polarization, is released during a short time interval and can be transformed into pulsed power. Compact explosive-driven power sources utilizing longitudinal shock wave depolarization of PZT elements of 0.35 to 3.3 cm3 volume are capable of producing pulses of high voltage, with amplitudes up to 22 kV, and up to 350 kW peak power.

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

2006-07-01

432

Camargo Waste to Energy Power Plant Hamed Zamenian1  

E-print Network

Camargo Waste to Energy Power Plant Hamed Zamenian1 , Eminou Nasser 1 , Matt Ray2 , Tom Iseley3 1 and Technology, IUPUI The Camargo Waste to Energy Power plant project is being proposed to dispose of Municipal Solid Waste (MSW) produced in Mexico. Currently, most urban Municipal Solid Wastes in Mexico

Zhou, Yaoqi

433

Spacecraft Power Beaming Using High-Energy Lasers, Experimental Validation  

Microsoft Academic Search

The lifetime of many spacecrafts are often limited by degradation of their electrical power subsystem, e.g. radiation-damaged solar arrays or failed batteries. Being able to beam power from terrestrial sites using high energy lasers, could alleviate this limitation, extending the lifetime of billions of dollars of satellite assets, as well as providing additional energy for electric propulsion that can be

Sherif Michael; Sherif

2008-01-01

434

Contribution to the Chapter on Wind Power Energy Technology  

E-print Network

.5.3 Benefits to national turnover and employments 15 2.6 Technology and Industry 16 2.6.1 TechnologyContribution to the Chapter on Wind Power Energy Technology Perspectives 2008 Jørgen Lemming; Poul Power Energy Technology Perspectives 2008 Division: Division Risø-R-1674(EN) January 2008 Abstract

435

Experimental determinations of electron stopping power at low energies  

Microsoft Academic Search

An accurate knowledge of electron stopping power is important for calculations and simulations of electron beam interactions with solids especially in the low energy region (< 10 keV). This paper describes a simplified and rapid experimental procedure using based on electron energy loss spectroscopy which permits accurate stopping power determinations to be made from any material which can be observed

Suicho Luo; Xiao Zhang; David C. Joy

1991-01-01

436

A fast maximum power extraction algorithm for wind energy systems  

Microsoft Academic Search

With the advancements in the variable speed direct drive design and control of wind energy systems, the efficiency and energy capture of these systems is also increasing. As such, many maximum power point tracking methods have been developed and implemented. These MPPT algorithms can be broadly categorized into three types: Tip-Speed control, Power- Signal feedback, and Hill climb search based.

Shravana Musunuri; H. L. Ginn III

2011-01-01

437

Comprehensive review of wind energy maximum power extraction algorithms  

Microsoft Academic Search

With the advancements in the variable speed direct drive design and control of wind energy systems, the efficiency and energy capture of these systems is also increasing. As such, many maximum power point tracking methods have been developed and implemented. These MPPT algorithms can be broadly categorized into three types: Tip-Speed control, Power- Signal feedback, and Hill climb search based.

Shravana Musunuri; H. L. Ginn III

2011-01-01

438

Comparison of energy harvesting power management techniques and application  

Microsoft Academic Search

There has been a significant increase in the research on energy harvesting device for low power applications in recreant years. This is due to smaller electronics power applications such as wireless and mobile electronics and the demand for better lifespan of batteries. One of the challenges of the harvesting energy from ambient is to convert, transfer and store the usable

M. S. M. Resali; H. Salleh

2010-01-01

439

Wave energy potential in the Eastern Mediterranean Levantine Basin. An integrated 10-year study  

E-print Network

but also stable, and hence exploitable, wave energy potential is revealed. However, non-trivial impact of en- ergy, the most crucial of which is the low variability, especially when compared with wind energy that remains to be covered before wave energy science and technology reach the maturity level of its wind

Georgiou, Georgios

440

Linear PM Generator system for wave energy conversion in the AWS  

Microsoft Academic Search

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

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

2004-01-01

441

Free energy in plasmas under wave-induced diffusion Nathaniel J. Fish  

E-print Network

Free energy in plasmas under wave-induced diffusion Nathaniel J. Fish Princeton Plasma Physics, the "Gardner free energy." Here, the plasma is rearranged incompressibly in the six- dimensional phase space of the plasma kinetic energy. In many cases of interest, the primary effect of the wave is to cause plasma

442

Impulsive Phase Flare Energy Transport by Large-Scale Alfvn Waves and the Electron Acceleration Problem  

E-print Network

Impulsive Phase Flare Energy Transport by Large-Scale Alfvén Waves and the Electron Acceleration IOPscience #12;IMPULSIVE PHASE FLARE ENERGY TRANSPORT BY LARGE-SCALE ALFVE´N WAVES AND THE ELECTRON The impulsive phase of a solar flare marks the epoch of rapid conversion of energy stored in the preflare

California at Berkeley, University of

443

Power Spectra to 1% Accuracy between Dynamical Dark Energy Cosmologies  

E-print Network

For dynamical dark energy cosmologies we carry out a series of N-body gravitational simulations, achieving percent level accuracy in the relative mass power spectra at any redshift. Such accuracy in the power spectrum is necessary for next generation cosmological mass probes. Our matching procedure reproduces the CMB distance to last scattering and delivers subpercent level power spectra at z=0 and z~3. We discuss the physical implications for probing dark energy with surveys of large scale structure.

Matthew J. Francis; Geraint F. Lewis; Eric V. Linder

2007-04-03

444

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

NASA Astrophysics Data System (ADS)

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

Guo, Bo; Tang, Jun; Cai, Bin; Zhu, YiMing

2014-12-01

445

Quantified energy dissipation rates in the terrestrial bow shock: 2. Waves and dissipation  

NASA Astrophysics Data System (ADS)

We present the first quantified measure of the energy dissipation rates, due to wave-particle interactions, in the transition region of the Earth's collisionless bow shock using data from the Time History of Events and Macroscale Interactions during Substorms spacecraft. Our results show that wave-particle interactions can regulate the global structure and dominate the energy dissipation of collisionless shocks. In every bow shock crossing examined, we observed both low-frequency (<10 Hz) and high-frequency (?10 Hz) electromagnetic waves throughout the entire transition region and into the magnetosheath. The low-frequency waves were consistent with magnetosonic-whistler waves. The high-frequency waves were combinations of ion-acoustic waves, electron cyclotron drift instability driven waves, electrostatic solitary waves, and whistler mode waves. The high-frequency waves had the following: (1) peak amplitudes exceeding ?B˜ 10 nT and ?E˜ 300 mV/m, though more typical values were ?B˜ 0.1-1.0 nT and ?E˜ 10-50 mV/m; (2) Poynting fluxes in excess of 2000 ?W m-2 (typical values were ˜1-10 ?W m-2); (3) resistivities > 9000 ? m; and (4) associated energy dissipation rates >10 ?W m-3. The dissipation rates due to wave-particle interactions exceeded rates necessary to explain the increase in entropy across the shock ramps for ˜90% of the wave burst durations. For ˜22% of these times, the wave-particle interactions needed to only be ? 0.1% efficient to balance the nonlinear wave steepening that produced the shock waves. These results show that wave-particle interactions have the capacity to regulate the global structure and dominate the energy dissipation of collisionless shocks.

Wilson, L. B.; Sibeck, D. G.; Breneman, A. W.; Contel, O. Le; Cully, C.; Turner, D. L.; Angelopoulos, V.; Malaspina, D. M.

2014-08-01

446

Polar lunar power ring: Propulsion energy resource  

NASA Technical Reports Server (NTRS)

A ring shaped grid of photovoltaic solar collectors encircling a lunar pole at 80 to 85 degrees latitude is proposed as the primary research, development, and construction goal for an initial lunar base. The polar Lunar Power Ring (LPR) is designed to provide continuous electrical power in ever increasing amounts as collectors are added to the ring grid. The LPR can provide electricity for any purpose indefinitely, barring a meteor strike. The associated rail infrastructure and inherently expandable power levels place the LPR as an ideal tool to power an innovative propulsion research facility or a trans-Jovian fleet. The proposed initial output range is 90 Mw to 90 Gw.

Galloway, Graham Scott

1990-01-01

447

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

E-print Network

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

Coleman, Piers

448

Design and optimization of a novel hybrid transverse \\/ longitudinal flux, wound-field linear machine for ocean wave energy conversion  

Microsoft Academic Search

This paper develops an analytical model for a novel double-sided hybrid transverse\\/longitudinal flux linear machine for use in ocean wave energy converter (WEC) applications. While several machine topologies exist for direct-drive power take-off in buoy-type WECs, the intent of this paper is to introduce a new type of linear machine for possible use as a direct-drive in future WECs. The

J. Vining; T.A. Lipo; G. Venkataramanan

2009-01-01

449

Unification of dark matter and dark energy via quantum wave function collapse  

Microsoft Academic Search

Dynamical wave function collapse models entail the continuous liberation of a specified rate of energy arising from the interaction of a fluctuating scalar field with the matter wave function. We consider the wave function collapse process for the constituents of dark matter in our universe. Beginning from a particular early era of the universe chosen from physical considerations, the rate

A. S. Majumdar

450

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

E-print Network

Shell-instability generated waves by low energy electrons on converging magnetic field lines D in the cusp, mantle or polar cap can be generated by shell-type electron distributions. We present an example that the shell-instability can generate electrostatic and electromagnetic wave modes: whistler waves, electron

California at Berkeley, University of

451

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

E-print Network

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

Sutherland, Bruce

452

Kuwait Energy Profile for Electrical Power Generation  

Microsoft Academic Search

The State of Kuwait, a major oil exporter, consumes a huge amount of its natural hydrocarbon resources to meet the rising demand for electricity. The forecasting of domestic energy demand and optimal allocation of energy resources are necessary requirements for a balanced energy policy. This article assesses the energy resources profile of Kuwait in order to reveal the potential base

Mohammad Ramadhan; Abdulhameed Hussain

2012-01-01

453

Wind Power: An Emerging Energy Resource  

ERIC Educational Resources Information Center

One may ask the question, What is energy? Typically the first answers that come to mind are oil, coal, and natural gas or nuclear energy. Most human activities require some form of energy consumption. This may be the energy produced by the food that one eats or the gasoline that is used in cars, trucks, buses, and other vehicles. One cannot ignore…

Deal, Walter F.

2010-01-01

454

Energy analysis of coal, fission, and fusion power plants  

NASA Astrophysics Data System (ADS)

The method of net energy analysis has been applied to coal, fission, and fusion power plants. Energy consumption over the lifetime of the plants has been calculated for construction, operation and maintenance, fuel, public welfare, and land use and restoration. Thermal and electric energy requirements were obtained separately for each energy consuming sector. The results of the study are presented in three ways: total energy requirements, energy gain ratio, and payback periods. All three types of power plants are net producers of energy. The coal and fusion power plants are superior to fission plants from the energy efficiency point of view. Fission plants will improve considerably if the centrifuge replaces the gaseous diffusion as a method of enrichment.

Tsoulfanidis, N.

1981-04-01

455

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

SciTech Connect

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

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

2008-05-15

456

Entanglement of helicity and energy in kinetic Alfvén wave/whistler turbulence  

NASA Astrophysics Data System (ADS)

abstract-type="normal"> The role of magnetic helicity is investigated in kinetic Alfvén wave and oblique whistler turbulence in presence of a relatively intense external magnetic field b 0 e ?. In this situation, turbulence is strongly anisotropic and the fluid equations describing both regimes are the reduced electron magnetohydrodynamics (REMHD) whose derivation, originally made from the gyrokinetic theory, is also obtained here from compressible Hall magnetohydrodynamics (MHD). We use the asymptotic equations derived by Galtier and Bhattacharjee (2003 Phys. Plasmas 10, 3065-3076) to study the REMHD dynamics in the weak turbulence regime. The analysis is focused on the magnetic helicity equation for which we obtain the exact solutions: they correspond to the entanglement relation, n + ñ = -6, where n and ñ are the power law indices of the perpendicular (to b 0) wave number magnetic energy and helicity spectra, respectively. Therefore, the spectra derived in the past from the energy equation only, namely n = -2.5 and ñ = -3.5, are not the unique solutions to this problem but rather characterize the direct energy cascade. The solution ñ = -3 is a limit imposed by the locality condition; it is also the constant helicity flux solution obtained heuristically. The results obtained offer a new paradigm to understand solar wind turbulence at sub-ion scales where it is often observed that -3 < n < -2.5.

Galtier, Sébastien; Meyrand, Romain

2015-01-01

457

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

PubMed

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