These are representative sample records from Science.gov related to your search topic.
For comprehensive and current results, perform a real-time search at Science.gov.
1

Power conversion mechanisms for wave energy  

Microsoft Academic Search

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

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

2002-01-01

2

Power electronic grid-interface for renewable ocean wave energy  

Microsoft Academic Search

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

Marian P. Kazmierkowski; Marek Jasinski

2011-01-01

3

Maximum Power Point Tracking for Ocean Wave Energy Conversion  

Microsoft Academic Search

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

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

2012-01-01

4

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

5

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.

6

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

7

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

Microsoft Academic Search

While wave energy is primarily a wind driven phenomenon, at a particular location and time the energy levels in the wind and waves may be different. The correlation between wind and wave energy is sufficiently weak that combining the two energy sources in a collocated offshore power plant reduces the variability in electrical generation. A preliminary examination of offshore locations

E. Stoutenburg

2008-01-01

8

Power output variations of co-located offshore wind turbines and wave energy converters in California  

Microsoft Academic Search

The electric power generation of co-located offshore wind turbines and wave energy converters along the California coast is investigated. Meteorological wind and wave data from the National Buoy Data Center were used to estimate the hourly power output from offshore wind turbines and wave energy converters at the sites of the buoys. The data set from 12 buoys consists of

Eric D. Stoutenburg; Nicholas Jenkins; Mark Z. Jacobson

2010-01-01

9

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

10

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

Microsoft Academic Search

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

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

2009-01-01

11

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

NASA Astrophysics Data System (ADS)

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

Stoutenburg, E.

2008-12-01

12

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

E-print Network

the Doubly- fed induction generator (DFIG). This paper deals then with a model-based predictive power control of a DFIG-based Wave Energy Converter (WEC). In the proposed control approach, the predicted output power was calculated using a DFIG linearized state-space model. The DFIG-based WEC power tracking performances further

Paris-Sud XI, Université de

13

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

14

Applications of high-power millimeter waves in fusion energy research  

Microsoft Academic Search

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

Timothy C. Luce

2002-01-01

15

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

E-print Network

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

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

2014-01-01

16

Cycloidal Wave Energy Converter  

SciTech Connect

This program allowed further advancing the development of a novel type of wave energy converter, a Cycloidal Wave Energy Converter or CycWEC. A CycWEC consists of one or more hydrofoils rotating around a central shaft, and operates fully submerged beneath the water surface. It operates under feedback control sensing the incoming waves, and converts wave power to shaft power directly without any intermediate power take off system. Previous research consisting of numerical simulations and two dimensional small 1:300 scale wave flume experiments had indicated wave cancellation efficiencies beyond 95%. The present work was centered on construction and testing of a 1:10 scale model and conducting two testing campaigns in a three dimensional wave basin. These experiments allowed for the first time for direct measurement of electrical power generated as well as the interaction of the CycWEC in a three dimensional environment. The Atargis team successfully conducted two testing campaigns at the Texas A&M Offshore Technology Research Center and was able to demonstrate electricity generation. In addition, three dimensional wave diffraction results show the ability to achieve wave focusing, thus increasing the amount of wave power that can be extracted beyond what was expected from earlier two dimensional investigations. Numerical results showed wave cancellation efficiencies for irregular waves to be on par with results for regular waves over a wide range of wave lengths. Using the results from previous simulations and experiments a full scale prototype was designed and its performance in a North Atlantic wave climate of average 30kW/m of wave crest was estimated. A full scale WEC with a blade span of 150m will deliver a design power of 5MW at an estimated levelized cost of energy (LCOE) in the range of 10-17 US cents per kWh. Based on the new results achieved in the 1:10 scale experiments these estimates appear conservative and the likely performance at full scale will exceed this initial performance estimates. In advancing the Technology Readiness Level (TRL) of this type of wave energy converter from 3 to 4, we find the CycWEC to exceed our initial estimates in terms of hydrodynamic performance. Once fully developed and optimized, it has the potential to not just outperform all other WEC technologies, but to also deliver power at a lower LCOE than competing conventional renewables like wind and solar. Given the large wave power resource both domestically and internationally, this technology has the potential to lead to a large improvement in our ability to produce clean electricity at affordable cost.

Stefan G. Siegel, Ph.D.

2012-11-30

17

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

18

Electromagnetic wave energy converter  

NASA Technical Reports Server (NTRS)

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

Bailey, R. L. (inventor)

1973-01-01

19

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

Microsoft Academic Search

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

A. F. de O Falcão

2002-01-01

20

Prototype testing of the wave energy converter wave dragon  

Microsoft Academic Search

The Wave Dragon is an offshore wave energy converter of the overtopping type. It consists of two wave reflectors focusing the incoming waves towards a ramp, a reservoir for collecting the overtopping water and a number of hydro turbines for converting the pressure head into power.In the period from 1998 to 2001 extensive wave tank testing on a scale model

Jens Peter Kofoed; Peter Frigaard; Erik Friis-Madsen; Hans Chr. Sørensen

2006-01-01

21

The Promise of Wave Power (Invited)  

NASA Astrophysics Data System (ADS)

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

Brekken, T.

2010-12-01

22

Wave powered buoy generator  

SciTech Connect

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

Rowe, R.A.

1985-01-08

23

Wave powered buoy generator  

SciTech Connect

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

Rowe, R.A.

1982-12-02

24

Energy of a shock wave generated in different metals under irradiation by a high-power laser pulse  

SciTech Connect

The energies of a shock wave generated in different metals under irradiation by a high-power laser beam were determined experimentally. The experiments were performed with the use of targets prepared from a number of metals, such as aluminum, copper, silver and lead (which belong to different periods of the periodic table) under irradiation by pulses of the first and third harmonics of the PALS iodine laser at a radiation intensity of approximately 10{sup 14} W/cm{sup 2}. It was found that, for heavy metals, like for light solid materials, the fraction of laser radiation energy converted into the energy of a shock wave under irradiation by a laser pulse of the third harmonic considerably (by a factor of 2-3) exceeds the fraction of laser radiation energy converted under irradiation by a laser pulse of the first harmonic. The influence of radiation processes on the efficiency of conversion of the laser energy into the energy of the shock wave was analyzed.

Gus'kov, S. Yu. [Russian Academy of Sciences, Lebedev Physical Institute (Russian Federation)], E-mail: guskov@sci.lebedev.ru; Kasperczuk, A.; Pisarczyk, T.; Borodziuk, S. [Institute of Plasma Physics and Laser Microfusion (Poland); Ullschmied, J. [Kaliski Institute of Plasma Physics of the Academy of Sciences of the Czech Republic (Czech Republic); Krousky, E.; Masek, K.; Pfeifer, M.; Skala, J. [Institute of Physics of the Academy of Sciences of the Czech Republic (Czech Republic); Pisarczyk, P. [Warsaw University of Technology (Poland)

2007-10-15

25

Hydroelectric power from ocean waves  

Microsoft Academic Search

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

K. Raghavendran

1981-01-01

26

Wave-operated power plant  

Microsoft Academic Search

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

Ghesquiere

1980-01-01

27

Proposed electromagnetic wave energy converter  

NASA Technical Reports Server (NTRS)

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

Bailey, R. L.

1973-01-01

28

Grid connection for wave power farms  

Microsoft Academic Search

Linear generators used as direct-drive solution in wave energy conversion have the main advantage of higher efficiency and more simple and robust system. However there are some important drawbacks that should be solved to increase the reliability and feasibility. This paper will study in detail the problem of the power oscillation introduced intro the electric grid due to the zero

Marcos Lafoz; Marcos Blanco; Dionisio Ramirez

2011-01-01

29

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

E-print Network

alternative or renewable energy sources is becoming a necessity. Among renewable energy harvesting decades, renewable energy resources are considered as an alternative energy resource to the World's excessive energy demand. An extremely abundant and promising source of energy exists in oceans. Currently

Brest, Université de

30

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

31

Modeling wave power extraction devices will help engineers identify best design  

E-print Network

. Several pilot installations already harvest wave power, and the first commercial wave farm began operating for wave power extraction devices, none is dominant or in commercial development. Many wave-energy device and deployment of units present major challenges to widespread development of wave-energy extraction devices

Entekhabi, Dara

32

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

33

Power recycling for an interferometric gravitational wave  

E-print Network

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

Ejiri, Shinji

34

Wave energy prospect of Bangladesh  

Microsoft Academic Search

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

M. J. Sarker; Imranul Karim; Shirajum Munir

2009-01-01

35

Wave energy resource characterization and the evaluation of potential Wave Farm sites  

Microsoft Academic Search

In theory, the energy that could be extracted from ocean waves is in excess of any current, or future, human requirements. Methods to evaluate and compare the wave energy resource at different locations are required in order to inform the developers of Wave Energy Converter (WEC) projects and allow them to select the most favorable sites for achieving optimal power

Brendan Cahill; Tony Lewis

2011-01-01

36

Wave energy and intertidal productivity  

Microsoft Academic Search

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

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

1987-01-01

37

Research today for tomorrow's power. [Geothermal, solar, wave, wind and tidal possibilities  

Microsoft Academic Search

Much R and D will be required for solar, tidal, wave, wind, and geothermal energy to be exploited on a large scale in the UK. Wind energy is widely available but irregular and variable, the basic problem being storage. Tidal and wave power are of practical interest only to large electricity supply organizations; wave power is more of a conventional

Beatson

1976-01-01

38

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

39

High power millimeter wave source development program  

NASA Technical Reports Server (NTRS)

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

George, T. V.

1989-01-01

40

Wave-powered electrolysis of water  

SciTech Connect

An offshore water electrolysis plant which produces pressurized gas by electrolysis of fresh water and wave power includes the combination of a wave-powered electric generator at the ocean surface, an electrolyzer and storage vessels located on the ocean bottom for providing gas under pressure, and a source of fresh water at the ocean surface forced down to the submerged electrolyzer through the use of a water-filled standpipe. In one embodiment, the electric power generating system includes a tethered floating helix coupled to an electric generator, in which the helix is automatically aligned with the wave propagation direction, while in another embodiment linear alternators are mounted for reciprocation on a column which extends through the air-sea interface, with each alternator provided with a donut-shaped float, such that electric power is generated as each float moves vertically up and down responsive to wave motion.

Lapeyre, J. M.

1984-12-25

41

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

E-print Network

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

Anand, R K

2014-01-01

42

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

43

Quantifying the Benefits of Combining Offshore Wind and Wave Energy  

Microsoft Academic Search

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

E. Stoutenburg; M. Z. Jacobson

2009-01-01

44

Power spectra of infragravity waves in a deep ocean  

NASA Astrophysics Data System (ADS)

waves (IGWs) play an important role in coupling wave processes in the ocean, ice shelves, atmosphere, and the solid Earth. Due to the paucity of experimental data, little quantitative information is available about power spectra of IGWs away from the shore. Here we use continuous, yearlong records of pressure at 28 locations on the seafloor off New Zealand's South Island to investigate spectral and spatial distribution of IGW energy. Dimensional analysis of diffuse IGW fields reveals universal properties of the power spectra observed at different water depths and leads to a simple, predictive model of the IGW spectra. While sources of IGWs off New Zealand are found to have a flat power spectrum, the IGW energy density has a pronounced dependence on frequency and local water depth as a result of the interaction of the waves with varying bathymetry.

Godin, Oleg A.; Zabotin, Nikolay A.; Sheehan, Anne F.; Yang, Zhaohui; Collins, John A.

2013-05-01

45

Near Shore Wave Modeling and applications to wave energy estimation  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

46

297 W continuous-wave output power  

Microsoft Academic Search

We have demonstrated a high-power and high-efficiency erbium:ytterbium (Er:Yb) co-doped fiber laser that produces 297 W of continuous-wave output at 1567 nm. The slope efficiency with respect to the launched pump power changed from 40% to 19% at higher output power due to the onset of Yb co-lasing at 1067 nm. However, the Yb co-lasing was essential for the suppression

Y. Jeong; S. Yoo; C. A. Codemard; J. Nilsson; J. K. Sahu; D. N. Payne; R. Horley; P. W. Turner; Louise Hickey; Andrew Harker; Mike Lovelady

47

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

48

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

49

Power conditioning system for energy sources  

DOEpatents

Apparatus for conditioning power generated by an energy source includes an inverter for converting a DC input voltage from the energy source to a square wave AC output voltage, and a converter for converting the AC output voltage from the inverter to a sine wave AC output voltage.

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

2008-05-13

50

Direct Drive Wave Energy Buoy  

SciTech Connect

The most prudent path to a full-scale design, build and deployment of a wave energy conversion (WEC) system involves establishment of validated numerical models using physical experiments in a methodical scaling program. This Project provides essential additional rounds of wave tank testing at 1:33 scale and ocean/bay testing at a 1:7 scale, necessary to validate numerical modeling that is essential to a utility-scale WEC design and associated certification.

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

2013-07-29

51

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.,

52

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

53

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

54

Sunspot waves and flare energy release  

E-print Network

We address a possibility of the flare process initiation and further maintenance of its energy release due to a transformation of sunspot longitudinal waves into transverse magnetic loop oscillations with initiation of reconnection. This leads to heating maintaining after the energy release peak and formation of a flat stage on the X-ray profile. We applied the time-distance plots and pixel wavelet filtration (PWF) methods to obtain spatio-temporal distribution of wave power variations in SDO/AIA data. To find magnetic waveguides, we used magnetic field extrapolation of SDO/HMI magnetograms. The propagation velocity of wave fronts was measured from their spatial locations at specific times. In correlation curves of the 17 GHz (NoRH) radio emission we found a monotonous energy amplification of 3-min waves in the sunspot umbra before the 2012 June 7 flare. This dynamics agrees with an increase in the wave-train length in coronal loops (SDO/AIA, 171 {\\AA}) reaching the maximum 30 minutes prior to the flare onset...

Sych, R; Altyntsev, A; Dudík, J; Kashapova, L

2014-01-01

55

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

56

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

57

Wave energy propelling marine ship  

Microsoft Academic Search

A wave energy propelling marine ship comprises a cylindrical ship body having a hollow space therein for transporting fluid material therewithin, a ship body disposed in or on the sea; a propeller attached to the ship body for the purpose of propelling the marine ship for sailing; a rudder for controlling the moving direction of the marine ship; at least

Kitabayashi

1982-01-01

58

On the wave energy potential of Western Black Sea shelf  

E-print Network

In the present study we evaluate the approaches to estimate the wave energy potential of the western Black Sea shelf with numerical models. For the purpose of our evaluation and due to the lack of long time series of measurements in the selected area of the Black Sea, we compare the modeled mean wave power flux output from the SWAN wave model with the only available long term measurements from the buoy of Gelendzhik for the period 1997-2003 (with gaps). The forcing meteorological data for the numerical wave models for the selected years is extracted from the ERA Interim reanalysis of ECMWF (European Centre for Medium range Forecasts). For the year 2003 we also compare the estimated wave power with the modeled by SWAN, using ALADIN regional atmospheric model winds. We try to identify the shortcomings and limitations of the numerical modeling approach to the evaluation of the wave energy potential in Black Sea.

Galabov, Vasko

2013-01-01

59

Wave refraction and wave energy on Cayo Arenas  

E-print Network

Extending Wave Refraction Beyond Breaker Zone on Four Second Diagrams IIb Data for Extending Wave Refraction Beyond Breaker Zone on Eight Second Diagrams 38 IIc Data for Extending Wave Refraction Beyond Breaker Zone on Twelve Second Diagrams U 2... Squares 081 and 082, 2 Wind Rose for Cayo Arenas Area, 3 Schematic Diagram Defining Quantities Used in Power Calculations. 14 4 Simplified Refraction Diagram Showmg Use of Graphical Aid in Construction (as copied from H. O. Pub. 234). Sa Zones...

Walsh, Donald Eugene

2012-06-07

60

IEEE Power and Energy  

NSDL National Science Digital Library

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

2003-01-01

61

Structure of the Electric Field of a High-Power Radio Wave in the Outer Ionosphere  

NASA Astrophysics Data System (ADS)

The electric field of a high-power HF radio wave radiated by the Sura facility was measured using onboard instruments of the French microsatellite DEMETER at altitudes of 670 km. The data analysis shows that the high-power radio wave passes to the outer ionosphere under conditions where the difference between the cutoff frequency and the pump-wave frequency does not exceed 0.5-0.7 MHz in the undisturbed ionosphere. Energy and spatial characteristics of the high-power radio wave transmitted through the ionosphere are determined. A possible mechanism explaining such a penetration to the supercritical plasma is discussed.

Frolov, V. L.; Mityakov, N. A.; Shorokhova, E. A.; Parrot, M.

2013-11-01

62

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

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

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

E-print Network

: - Point Absorbers - Oscillating Water Column (e.g., NWEI, Carnegie, Columbia Power, OPT) (e.g., Ocean + concrete sinkers Power 30m site Deep sites Water depth One @ 30m Two sites @ June 10, 2013 #12;Wave Energy Test Site (WETS) Objective: Provide location for year-long in-water

65

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

PubMed

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

Bose, N; Lien, J

1990-06-22

66

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

67

Note on Salter's energy absorber in random waves  

SciTech Connect

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

Serman, D.D. (Estudio de Ingenieria Hidraulica, Buenos Aires, Argentina); Mei, C.C. (MIT, Cambridge, Mass.)

1980-01-01

68

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

69

Counter-rotating wave energy conversion turbine  

SciTech Connect

A counter-rotating turbine for converting energy from waves. A turbine is positioned in a pneumatic-type wave energy converter and converts the energy of alternating air flow above the internal water surface into mechanical energy. The turbine has counter-rotating runners and guide vanes located both upstream and downstream, and the alternating air flow in the energy converter excites the turbine runners after being turned by the guide vanes.

McCormick, M.E.

1981-06-09

70

Azimuthal Distribution of ULF Wave Power in the Magnetosphere  

NASA Astrophysics Data System (ADS)

The Van Allen radiation belts contain highly energetic particles which interact with a variety of plasma and MHD waves. ULF waves play an important role in loss and acceleration of energetic particles. There is still much to be understood about the interaction between charged particles and ULF waves and how these waves influence diffusion of charged particles. We will investigate how ULF wave power distribution in azimuth affects radial diffusion of charged particles. We will present results from CRRES (Combined Release and Radiation Effect Satellite) magnetometer data study regarding the azimuthal distribution of wave power in the geomagnetic field. Current theoretical treatments of radial diffusion assume a constant power distribution in azimuth while our results show that this is clearly not the case. Our ongoing investigation includes further study of azimuthal distribution of wave power as well as the distribution of wave power across different mode numbers. In order to use the in situ point measurements such as from a spacecraft, it is necessary to assume that all of the wave power exists in the first mode. But how valid is this assumption? How much power is contained in the higher modes? These are some of the questions we wish to investigate as a part of our ongoing study to better our understanding of particle dynamics in the magnetosphere.

Ali, A.; Elkington, S. R.

2013-12-01

71

Wave energy extraction by coupled resonant absorbers.  

PubMed

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

Evans, D V; Porter, R

2012-01-28

72

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

73

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

ERIC Educational Resources Information Center

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

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

2008-01-01

74

Wave Energy Resources Representative Sites Around the Hawaiian Islands  

E-print Network

Wave Power Resources: Update p9 Shallow Water Wave Power Resources: Update p11 References p20 Figure 1. Vega Ph.D October 11, 2010 #12;Wave Power Resources off the Hawaiian Islands October 11, 2010 1 of Contents Summary p2 Background: Wave Power Conversion p3 Licensing and Permitting p3 Challenges

75

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

76

Ocean, Wave, and Tidal Energy Systems: Current abstracts  

NASA Astrophysics Data System (ADS)

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

Smith, L.; Lane, D. W.

1988-01-01

77

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

E-print Network

Using a Bore-Soliton-Splash to understand Rogue Waves, Tsunamis & Wave Energy Onno Bokhove, Elena it. · Explore: relation w. tsunamis, wave pumps & wave energy? 2 Set-up Water Wave Channel · Two. Combined research on stowage through contractions with wave impact against walls; case 8: 3.5­4m splash [7

Wirosoetisno, Djoko

78

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

79

Virginia Power's alternative energy study  

Microsoft Academic Search

In June 1981, the management of Virginia Electric and Power Company (now Virginia Power, or the Power Company) appointed a committee to formulate a study of conventional and alternative energy sources to meet future growth in electric power demand in a least-cost manner. This Committee on Conventional and Alternative Energy Sources recommended several energy alternatives for evaluation. The alternatives for

1986-01-01

80

Simulation of coastal wave spectra energy from ENVISAT satellite data  

NASA Astrophysics Data System (ADS)

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

Marghany, Maged

2014-06-01

81

Nonresonant power transfer in plasma-surface interactions via two-surface wave decay  

SciTech Connect

The excitation of pairs of electron surface waves via nonresonant decay of plasma waves incident onto a solid surface is studied in the context of controlling the interaction of pulsed electromagnetic radiation with plasma-exposed solid surfaces. The role of the plasma-exposed surfaces in nonlinear heating of the plasma edge and related power transfer is discussed. It is shown that the maximum efficiency of the power transfer at solid surfaces with dielectric permittivity {epsilon}{sub d}<3 corresponds to the resonant two-surface wave decay. On the other hand, for solids with {epsilon}{sub d}>3 the maximum power transfer efficiency is achieved through nonresonant excitation of the quasistatic surface waves. In this case the plasma waves generated by external radiation dissipate their energy into the plasma periphery most effectively.

Akimov, Yu. A. [Center for Waves and Complex Systems, School of Physics, University of Sydney, Sydney NSW 2006 (Australia); Institute of High Technologies, V. N. Karazin Kharkiv National University, 31 Kurchatov Ave., Kharkiv 61108 (Ukraine); Ostrikov, K. [Center for Waves and Complex Systems, School of Physics, University of Sydney, Sydney NSW 2006 (Australia)

2008-01-15

82

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

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

Wave Energy Resource Analysis for Use in Wave Energy Conversion  

E-print Network

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

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

2014-01-01

85

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, using only velocity field data, the time-averaged energy flux J and total radiated power P for two, the stream function . We test the method using data from a direct nu- merical simulation for tidal flow

Texas at Austin. University of

86

Power Waves and the Scattering Matrix  

Microsoft Academic Search

This paper discusses the physical meaning and prop-erties of the waves defined by [Equation], [Equation] where Vi, and Zi, are the voltage at and the current flowing into the ith port of a junction and Zi, is the impedance of the circuit connected to the ith port. The square of the magnitude of these waves is directly related to the

K. Kurokawa

1965-01-01

87

Counting energy packets in the electromagnetic wave  

E-print Network

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

Stefan Popescu; Bernhard Rothenstein

2007-05-18

88

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

89

High power electronic scanning millimeter-wave radar system design  

Microsoft Academic Search

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

Stephen M. Sekelsky; James Carswell

2006-01-01

90

A Full-Wave Rectifier for Interfacing with Multi-Phase Piezoelectric Energy Harvesters*  

E-print Network

A Full-Wave Rectifier for Interfacing with Multi-Phase Piezoelectric Energy Harvesters* N. J: TECHNOLOGY TRENDS: Energy Sources and Energy Harvesting Abstract A full-wave rectifier has been fabricated-electrode piezoelectric transducer to be rectified with reduced output ripple. The rectifier has a measured power

Hurst, Paul J.

91

Guidelines in Wave Energy Conversion System Design  

E-print Network

This paper presents an investigational study on wave energy converters (WECs). The types of WEC available from the market are studied first. The design considerations for implementing a WEC in the Gulf of Mexico (GOM) are then evaluated...

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

2014-01-01

92

Self-similar relativistic blast waves with energy injection  

NASA Astrophysics Data System (ADS)

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

van Eerten, Hendrik

2014-08-01

93

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

94

Maximum power transfer for full-wave rectifier circuits  

Microsoft Academic Search

With a view to such potential applications as implanted medical instruments, inductive power transfer to weapons, power transfer by means of space reflectors, and power generation in space, an analysis is conducted to ascertain the maximum power transfer conditions for full wave rectifier circuits. The optimum ratio of ac-to-dc voltage output is determined for resistive\\/inductive, resistive\\/capacitive, and resistive\\/inductive\\/capacitive types of

R. J. Arthur

1983-01-01

95

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

96

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

97

Ocean power for Australia waves, tides and ocean currents  

Microsoft Academic Search

A preliminary resource assessment is made for three forms of Ocean Renewable Energy in Australia. The wave energy incident on the south coast of Australia constitutes Australia's principal resource of ocean renewable energy. Integrating the total energy flux crossing the 25m isobath between Geraldton WA and the southern tip of Tasmania, we estimate the total size of this resource to

D. Griffin; M. Hemer

2010-01-01

98

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

99

Wave Energy challenges and possibilities  

E-print Network

absorber, with either water pumps, linear generators or hydraulic power take off systems. Multi point of Ã? 5 m and operates in 10 m of water depth. In 2,5 m Hs the power output is 500 kW. The scale 1:1 converter is 240 m long with 40 floats of each Ã?10 m and operates in 20 m of water. In 5,0 m Hs the power

100

Modeling of an ocean waves power device AWS  

Microsoft Academic Search

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

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

2003-01-01

101

Theoretical modelling of two wave-power devices  

E-print Network

Many wave energy devices are currently studied. In this thesis we focus on two specific devices: the Oscillating Water Column (OWC), and the buoys. In the first part of this thesis we examine the effects of coastline ...

Lovas, Stéphanie

2010-01-01

102

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

SciTech Connect

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

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

2008-01-01

103

Simulation of high-power electromagnetic wave heating in the ITER burning plasma  

NASA Astrophysics Data System (ADS)

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

Jaeger, E. F.; Berry, L. A.; D'Azevedo, E. F.; Barrett, R. F.; Ahern, S. D.; Swain, D. W.; Batchelor, D. B.; Harvey, R. W.; Myra, J. R.; D'Ippolito, D. A.; Phillips, C. K.; Valeo, E.; Smithe, D. N.; Bonoli, P. T.; Wright, J. C.; Choi, M.

2008-07-01

104

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

105

PBS Learning Media: Origins of Wave Energy  

NSDL National Science Digital Library

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

106

Ion-acoustic solitary waves in a high power pulsed magnetron sputtering discharge  

Microsoft Academic Search

We report on the creation and propagation of ion-acoustic solitary waves in a high power pulsed magnetron sputtering discharge. A dense localized plasma is created by applying high energy pulses (4–12 J) of length ?70 µs, at a repetition frequency of 50 pulses per second, to a planar magnetron sputtering source. The temporal behaviour of the electron density, measured by

K B Gylfason; J Alami; U. Helmersson; J T Gudmundsson

2005-01-01

107

Wave-actuated power take-off device for electricity generation  

SciTech Connect

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

Chertok, Allan

2013-01-31

108

Energy flux measurement from the dissipated energy in capillary wave turbulence  

E-print Network

We study experimentally the influence of dissipation on stationary capillary wave turbulence on the surface of a fluid by changing its viscosity. We observe that the frequency power law scaling of the capillary spectrum departs significantly from its theoretical value when the dissipation is increased. The energy dissipated by capillary waves is also measured and found to increase nonlinearly with the mean power injected within the fluid. Here, we propose an experimental estimation of the energy flux at every scale of the capillary cascade. The latter is found to be non constant through the scales. For fluids of low enough viscosity, we found that both capillary spectrum scalings with the frequency and the newly defined mean energy flux are in good agreement with wave turbulence theory. The Kolmogorov-Zakharov constant is then experimentally estimated and compared to its theoretical value.

Luc Deike; Michaël Berhanu; Eric Falcon

2013-09-26

109

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

110

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

E-print Network

Farms: Siting, Ocean Area Requirements p7 Offshore Wave Power Resources: Update p9 Shallow Water Wave identified in the George Hagerman 1992 Report p8 Figure 2 - Hawaii Wave Power Climate Patterns p10 Figure 3 operating devices transmitting electricity to distribution lines (i.e., utility interconnected): the 500 k

111

Surface Wave Enhanced Turbulence as an important source energy  

E-print Network

Surface Wave Enhanced Turbulence as an important source energy maintaining/regulating Thermohaline by realistic surface wave enhanced diffusivity · Conclusion 9/15/2006 8 #12;9/15/2006 9 Mechanical energy;Surface wave energy input (mW/m/m, Wang & Huang, 2004) 9/15/2006 11 #12;Wind energy is more important: 1

112

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

113

Path loss prediction of electromagnetic wave from the micro power  

Microsoft Academic Search

Results of the measurement of electromagnetic waves from the micro power conducted in short-distance environments at 900 MHz and 1800 MHz are presented. The data were obtained in four different environments in Beijing. Some analytical models are presented to predict the path loss in short distance. These models show that the path loss exponent value is close to the value

Hai Ren; Yinghong Wen

2002-01-01

114

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

115

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

116

Wave energy transmission apparatus for high-temperature environments  

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

117

Shock wave generated by high-energy electric spark discharge  

NASA Astrophysics Data System (ADS)

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

Liu, Qingming; Zhang, Yunming

2014-10-01

118

Effects of high power ion Bernstein waves on a tokamak plasma  

SciTech Connect

Ion Bernstein wave heating (IBWH) has been investigated on PLT with up to 650 kW of rf power coupled to the plasma, exceeding the ohmic power of 550 kW. Plasma antenna loading of 2 ..cap omega.. has been observed, resulting in 80 to 90% of the rf power being coupled to the plasma. An ion heating efficiency of ..delta..T/sub i/(0)n/sub e//P/sub rf/ = 6 x 10/sup 13/ eV cm/sup -3//kW, without high energy tail ions, has been observed up to the maximum rf power. The deuterium particle confinement during high power IBWH increases significantly (as much as 300%). Associated with it, a longer injected impurity confinement time, reduced drift wave turbulence activity, frequency shifts of drfit wave turbulence, and development of a large negative edge potential were observed. The energy confinement time, however, shows some degradation from the ohmic value, which can be attributed to the enhanced radiation loss observed during IBWH. The ion heating and energy confinement time are relatively independent of plasma current.

Ono, M.; Beiersdorfer, P.; Bell, R.; Bernabei, S.; Cavallo, A.; Chmyga, A.; Cohen, S.; Colestock, P.; Gammel, G.; Greene, G.J.

1987-04-01

119

Localized wave transport of pulsed beam energy  

SciTech Connect

This paper describes the theory and experiments used to measure a new type of finite beam pulse, the localized wave pulse. The LW pulse is a linear superposition of Gaussian-like basis functions which are constructed from the focus wave modes of Brittingham by means of the modified power spectrum. Experiments to data have made use of three techniques. Synthetic array experiments using acousto-optic measurements were first undertaken to see if the localized wave pulses could be launched by normal acoustic devices. Next, synthetic array two transducer measurements were done to see if the beam generated would outperform a conventional continuous wave or pulsed array with both Gaussian shading and no shading. Finally, real array experiments were performed to see if the beam could be launched with actual acoustic arrays and still perform as well as in the synthetic array measurements. In all cases, the LW pulse has outperformed comparable beams by a wide margin. The theory will be outlined and the methods of measurement sketched. Finally, comparison of beams produced by driving the array with different inputs will be presented. 3 refs., 3 figs.

Lewis, D.K.; Ziolkowski, R.W. (Lawrence Livermore National Lab., CA (USA)); Cook, B.D. (Houston Univ., TX (USA))

1990-06-01

120

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.

Congden, Diana

2012-06-14

121

Energy 101: Concentrating Solar Power  

NSDL National Science Digital Library

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

National Renewable Energy Laboratory (NREL)

122

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

123

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

1993-12-01

124

Floating type ocean wave power station equipped with hydroelectric unit  

NASA Astrophysics Data System (ADS)

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

Okamoto, Shun; Kanemoto, Toshiaki; Umekage, Toshihiko

2013-10-01

125

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

126

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

127

A powerful reflector in relativistic backward wave oscillator  

NASA Astrophysics Data System (ADS)

An improved TM021 resonant reflector is put forward. Similarly with most of the slow wave structures used in relativistic backward wave oscillator, the section plane of the proposed reflector is designed to be trapezoidal. Compared with the rectangular TM021 resonant reflector, such a structure can depress RF breakdown more effectively by weakening the localized field convergence and realizing good electrostatic insulation. As shown in the high power microwave (HPM) generation experiments, with almost the same output power obtained by the previous structure, the improved structure can increase the pulse width from 25 ns to over 27 ns and no obvious surface damage is observed even if the generated HPM pulses exceed 1000 shots.

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

2014-09-01

128

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

E-print Network

with this is the consistency of the source of power. Two of the leading renewable energy sources wind and conventional hydro-electrical, hydroelectric, green energy. I. INTRODUCTION The Wing-Wave system (Fig. 1) is an alternate energy generation with the added benefit of not producing greenhouse gasses associated with the combustion of fuels used

Wood, Stephen L.

129

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

130

On the dynamics of a novel ocean wave energy converter  

Microsoft Academic Search

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

B. Orazov; O. M. O’Reilly; Ö. Savas

2010-01-01

131

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

132

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

133

Ion-acoustic solitary waves in a high power pulsed magnetron sputtering discharge  

Microsoft Academic Search

We report on the creation and propagation of ion-acoustic solitary waves in a high power pulsed magnetron sputtering discharge. A dense localized plasma is created by applying high energy pulses (4-12 J) of length ap70 µs, at a repetition frequency of 50 pulses per second, to a planar magnetron sputtering source. The temporal behaviour of the electron density, measured by

K. B. Gylfason; J. Alami; U. Helmersson; J. T. Gudmundsson

2005-01-01

134

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

Microsoft Academic Search

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

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

2011-01-01

135

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

136

Power and energy for posterity  

NASA Technical Reports Server (NTRS)

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

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

1972-01-01

137

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

138

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

139

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

140

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

SciTech Connect

Techniques are described which have been employed to develop detailed, quantitive estimates of the available ocean wave energy flux. A summary of results for a region of particular interest to potential U.S. developers of wave energy systems-the U.S. Northwest Pacific Coast - is also presented. Comparisons with results of other studies are made. In addition, a method for predicting the amount of mechanical energy captured by a conversion device, based on a frequency domain technique, is presented. Results are predicted for an articulated, contour following raft deployed in deep, open water west of the mouth of the Columbia River.

Burdette, E.L.; Gordon, C.K.

1983-12-01

141

Cosmology with space-based gravitational-wave detectors: Dark energy and primordial gravitational waves  

NASA Astrophysics Data System (ADS)

Proposed space-based gravitational-wave (GW) detectors such as DECIGO and BBO will detect ˜106 neutron-star (NS) binaries and determine the luminosity distances to the binaries with high precision. Combining the luminosity distances with cosmologically induced phase corrections on the GWs, cosmological expansion out to high redshift can be measured without the redshift determinations of host galaxies by electromagnetic observation and be a unique probe for dark energy. On the other hand, such a NS-binary foreground should be subtracted to detect primordial GWs produced during inflation. Thus, the constraining power on dark energy and the detectability of the primordial gravitational waves strongly depend on the detector sensitivity and are in close relation with one another. In this paper, we investigate the constraints on the equation of state of dark energy with future space-based GW detectors with/without identifying the redshifts of host galaxies. We also study the sensitivity to the primordial GWs, properly dealing with the residual of the NS-binary foreground. Based on the results, we discuss the detector sensitivity required to achieve the forementioned targeted study of cosmology.

Nishizawa, Atsushi; Yagi, Kent; Taruya, Atsushi; Tanaka, Takahiro

2012-02-01

142

Coupling of ICRF waves and axial transport of high-energy ions owing to spontaneously excited waves in the GAMMA 10 tandem mirror  

NASA Astrophysics Data System (ADS)

Plasmas with high ion temperature of several kiloelectronvolts and a strong temperature anisotropy of greater than 10 were produced by ion cyclotron range of frequency (ICRF) heating in the GAMMA 10 tandem mirror. In such high-performance plasmas with strong anisotropy, high-frequency fluctuations, so-called Alfvén-ion-cyclotron (AIC) waves, are excited spontaneously. These AIC waves have several discrete peaks in the frequency spectrum. Coupling of the ICRF heating waves and the excited AIC waves was clearly observed in the density fluctuations measured with a newly developed reflectometer. Parametric decay from the heating ICRF waves to the AIC waves and low-frequency waves was also indicated. Alfvén waves with difference frequencies between the discrete peaks of the AIC waves were detected in a signal that measured the number of axially transported high-energy ions (over 6 keV) at the machine end, indicating pitch-angle scattering caused by the low-frequency waves. Energy transport along the magnetic field line is an important consideration when ICRF power is injected in the perpendicular direction to a magnetic field line. The importance of the spontaneously excited AIC waves for axial confinement of a tandem mirror through wave-wave couplings was demonstrated.

Ikezoe, R.; Ichimura, M.; Hirata, M.; Iwai, T.; Yokoyama, T.; Ugajin, Y.; Sato, T.; Iimura, T.; Saito, Y.; Yoshikawa, M.; Kohagura, J.; Shima, Y.; Imai, T.

2013-07-01

143

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

PubMed

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

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

2007-10-01

144

Experimental results using active control of traveling wave power flow  

NASA Technical Reports Server (NTRS)

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

Miller, David W.; Hall, Steven R.

1991-01-01

145

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

146

Scattered surface wave energy in the seismic coda  

USGS Publications Warehouse

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

Zeng, Y.

2006-01-01

147

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

148

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

149

Surface drift effect on wind energy transfer to waves  

Microsoft Academic Search

The effect of surface drift velocity on the energy transfer from the wind to ocean waves and the growth rate of the dominant surface wave was studied analytically. The model analyzed considered first the airflow above the surface wave to be turbulent, the thin drift shear layer to be viscous, and the flow beneath the drift flow to be potential.

Donghuo Zhou; Cesar Mendoza

1993-01-01

150

Breaking of Ice Sheets Using Shock Waves Produced by Pulsed Power  

NASA Astrophysics Data System (ADS)

The breaking of ice sheets using shock waves produced by a pulsed power generator is suggested as a new method for navigation of icebreakers in order to realize safe and quick navigation in icebound sea. The shock wave can be produced by discharge formation between the electrodes contacted to an ice sheet. Experimentally, the breaking of ice was achieved. When the ice was broken for an applied voltage of 48 kV, a maximum discharge current of approximately 1.5 kA, a maximum discharge power of approximately 40 MW and a discharge energy of approximately 33 J were obtained. The onset of discharge occurs approximately 30 ?s after applying the voltage. From the photograph and the voltage-current characteristics it seems that arc discharge occurs at the surface of the ice.

Ihara, Satoshi; Yamabe, Chobei

2003-05-01

151

Speech articulator measurements using low power EM-wave sensors  

SciTech Connect

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

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

1998-01-01

152

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

153

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

154

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

155

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

156

A Comparison of Power Spectra of Ocean Waves Obtained by an Analog and a Digital Method  

Microsoft Academic Search

Power spectra of ocean waves obtained by an analog method are presented. In the analog method, standard laboratory equipment is used and no design or development work is required. A sample power spectrum of aocean wave pressure record is obtained by the analog method, and this spectrum is compared with a power spectrum obtained by a digital analysis of the

1960-01-01

157

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 plasma of Alfve´n waves by high power pulse at the electron plasma frequency, Geophys. Res. Lett., 32, L08101, doi

California at Los Angles, University of

158

Enhancement of particle-wave energy exchange by resonance sweeping  

SciTech Connect

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

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

1996-01-01

159

Enhancement of particle-wave energy exchange by resonance sweeping  

SciTech Connect

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

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

1995-10-01

160

E2I EPRI Assessment Offshore Wave Energy Conversion Devices  

E-print Network

, government/industry, public/private collaborative program to assess and demonstrate the feasibilityE2I 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

161

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

162

Ocean wave energy overview and research at Oregon State University  

Microsoft Academic Search

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

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

2009-01-01

163

The Physics Classroom: Work, Energy, and Power  

NSDL National Science Digital Library

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

Henderson, Tom

2005-03-16

164

Exploring Energy, Power, and Transportation Technology.  

ERIC Educational Resources Information Center

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

Bowers, Donovan; Kellum, Mary

165

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 o...

Abdurakhimov, L V; Levchenko, A A; Kolmakov, G V; Lvov, Y V

2014-01-01

166

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

167

Short-term wave forecasting with AR models in real-time optimal control of wave energy converters  

Microsoft Academic Search

Time domain control of wave energy converters requires knowledge of future incident wave elevation in order to approach conditions for optimal energy extraction. Autoregressive models revealed to be a promising approach to the prediction of future values of the wave elevation only from its past history. Results on real wave observations from different ocean locations show that AR models allow

Francesco Fusco; John V. Ringwood

2010-01-01

168

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

E-print Network

On the Use of Computational Models for Wave Climate Assessment in Support of the Wave Energy Fulfillment of the Requirements for the Degree of MASTER OF APPLIED SCIENCE in the Department of Mechanical On the Use of Computational Models for Wave Climate Assessment in Support of the Wave Energy Industry

Victoria, University of

169

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

2005-06-22

170

Power scaling of continuous-wave and Q-switched hybrid fiber-bulk erbium lasers at 1645 nm  

Microsoft Academic Search

We report recent progress in the development of high-power Er,Yb fiber-laser-pumped Er:YAG lasers at 1645 nm operating in continous-wave and Q-switched regimes. Strategies for further scaling of output power and pulse energy are considered. Summary: Solid-state laser sources operating in the eyesafe wavelength regime around ~1.5-1.6 ?m have numerous applications and provide a good starting point for mid-infrared generation via

D. Y. Shen; J. K. Sahu; W. A. Clarkson

171

The effect of high energy shock waves focused on cortical bone: an in vitro study.  

PubMed

Extracorporeal shock wave lithotripsy has become an accepted alternative for the management of nephrolithiasis and cholelithiasis. Direct impact of shock waves cause tear and shear forces at transition sites between tissues with divergent acoustic impedances leading to stone fragmentation. The aim of this study was to determine whether shock waves can cause cortical bone damage at all and, if so, what the relationship is, if any, between the energy density of the shock waves, the number of shock waves applied, and the resulting cortical bone damage. With the Siemens Lithostar Plus with overhead module, electromagnetic shock waves, generated under water with energy densities of 0.23, 0.33, 0.42, or 0.54 mJ/mm2, corresponding with power settings 2, 4, 6, and 8, were applied to bone specimens, i.e., of rabbit femurs and tibiae. Prior to exposure to the shock waves, the bones were mounted on a specially constructed perspex holder which could be placed in a water-filled test basin with an elastic membrane in the front through which the shock waves propagate without loss of energy. This setup made it possible not only to induce complete fractures, but also to detect the existence of a linear relationship with a Spearman rank correlation coefficient of -0.72 (P < or = 0.01) between the energy level of the shock waves and the severity of the cortical bone defects. The latter findings are especially of great importance because this means that the process can be controlled and that the cortical effects will be predictable and reproducible. This study should be considered a preliminary test concerning the effects of high energy shock wave on bone.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8429638

Kaulesar Sukul, D M; Johannes, E J; Pierik, E G; van Eijck, G J; Kristelijn, M J

1993-01-01

172

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

Microsoft Academic Search

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

C. Josset; A. H. Clément

2007-01-01

173

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

174

High power continuous-wave titanium:sapphire laser  

DOEpatents

A high-power continuous-wave laser resonator (10) is provided, wherein first, second, third, fourth, fifth and sixth mirrors (11-16) form a double-Z optical cavity. A first Ti:Sapphire rod (17) is disposed between the second and third mirrors (12,13) and at the mid-point of the length of the optical cavity, and a second Ti:Sapphire rod (18) is disposed between the fourth and fifth mirrors (14,15) at a quarter-length point in the optical cavity. Each Ti:Sapphire rod (17,18) is pumped by two counter-propagating pump beams from a pair of argon-ion lasers (21-22, 23-24). For narrow band operation, a 3-plate birefringent filter (36) and an etalon (37) are disposed in the optical cavity so that the spectral output of the laser consists of 5 adjacent cavity modes. For increased power, seventy and eighth mirrors (101, 192) are disposed between the first and second mirrors (11, 12) to form a triple-Z optical cavity. A third Ti:Sapphire rod (103) is disposed between the seventh and eighth mirrors (101, 102) at the other quarter-length point in the optical cavity, and is pumped by two counter-propagating pump beams from a third pair of argon-ion lasers (104, 105).

Erbert, Gaylen V. (Livermore, CA); Bass, Isaac L. (Castro Valley, CA); Hackel, Richard P. (Livermore, CA); Jenkins, Sherman L. (Livermore, CA); Kanz, Vernon K. (Livermore, CA); Paisner, Jeffrey A. (Danville, CA)

1993-01-01

175

Experimental determination of radiated internal wave power without pressure field data  

E-print Network

We present a method to determine, using only velocity field data, the time-averaged energy flux $\\left$ and total radiated power $P$ for two-dimensional internal gravity waves. Both $\\left$ and $P$ are determined from expressions involving only a scalar function, the stream function $\\psi$. 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 ed...

Lee, Frank M; Swinney, Harry L; Morrison, P J

2014-01-01

176

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

177

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

NASA Astrophysics Data System (ADS)

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

Musielak, Zdzislaw E.

1986-12-01

178

Open cycle traveling wave thermoacoustics: Energy fluxes and thermodynamics  

Microsoft Academic Search

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

Nathan T. Weiland; Ben T. Zinn

2004-01-01

179

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

NASA Astrophysics Data System (ADS)

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

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

2012-05-01

180

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

181

High Power HF Excitation of Low Frequency Stimulated Electrostatic Waves in the Ionospheric Plasma over HAARP  

NASA Astrophysics Data System (ADS)

High Power electromagnetic (EM) waves transmitted from the HAARP facility in Alaska can excite low frequency electrostatic waves by several processes including (1) direct magnetized stimulated Brillouin scatter (MSBS) and (2) parametric decay of high frequency electrostatic waves into electron and ion Bernstein waves. Either an ion acoustic (IA) wave with a frequency less than the ion cyclotron frequency (fCI) or an electrostatic ion cyclotron (EIC) wave just above fCI can be produced by MSBS. The coupled equations describing the MSBS instabil-ity show that the production of both IA and EIC waves is strongly influenced by the wave propagation direction relative to the background magnetic field. Experimental observations of stimulated electromagnetic emissions (SEE) using the HAARP transmitter in Alaska have confirmed the theoretical predictions that only IA waves are excited for propagation along the magnetic zenith and that EIC waves can only be detected with oblique propagation angles. The electron temperature in the heated plasma is obtained from the IA spectrum offsets from the pump frequency. The ion composition can be determined from the measured EIC frequency. Near the second harmonic of the electron cyclotron frequency, the EM pump wave is converted into an electron Bernstein (EB) wave that decays into another EB wave and an ion Bernstein (IB) wave. Strong cyclotron resonance with the EB wave leads to acceleration of the electrons. Ground based SEE observations are related to the theory of low-frequency electrostatic wave generation.

Bernhardt, Paul; Selcher, Craig A.

182

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

NASA Astrophysics Data System (ADS)

Marine energy converter must both efficiently extract energy in small to moderate seas and also successfully survive storms and potential collisions. Extreme loads on devices are therefore an important consideration in their design process. X-MED is a SuperGen UKCMER project and is a collaboration between the Universities of Manchester, Edinburgh and Plymouth and the Scottish Association for Marine Sciences. Its objective is to extend the knowledge of extreme loads due to waves, currents, flotsam and mammal impacts. Plymouth Universities contribution to the X-MED project involves measuring the loading and response of a taut moored floating body due to steep and breaking wave impacts, in both long crested and directional sea states. These measurements are then to be reproduced in STAR-CCM+, a commercial volume of fluid CFD solver, so as to develop techniques to predict the wave loading on wave energy converters. The measurements presented here were conducted in Plymouth Universities newly opened COAST laboratories 35m long, 15.5m wide and 3m deep ocean basin. A 0.5m diameter taut moored hemispherical buoy was used to represent a floating wave energy device or support structure. The changes in the buoys 6 degree of freedom motion and mooring loads are presented due to focused breaking wave impacts, with the breaking point of the wave changed relative to the buoy.

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

2013-04-01

183

Spatial patterns of wave energy delivery to coastal cliffs  

Microsoft Academic Search

Recent studies have shown that wave energy delivery to coastal cliffs can be measured by proxy using arrays of seismometers that detect microseismic ground motion. There is considerable debate concerning the relative roles of subaerial weathering and wave processes in rocky coast evolution. Micro-seismic studies provide an important opportunity to progress understanding, because there have been relatively few quantitative measurements

M. E. Dickson; R. Pentney; M. Alvarez; P. Malin

2010-01-01

184

Energy flux of timeharmonic waves in anisotropic dissipative media  

E-print Network

Energy flux of time­harmonic waves in anisotropic dissipative media Vlastislav Ÿ Cerven­harmonic waves propagating in anisotropic dissipative media may be introduced in several ways. It is most common quantities are investigated for general anisotropic dissipative media, mainly in relation to the reflection

Cerveny, Vlastislav

185

A Morphing Blade for Wave and Wind Energy Conversion  

Microsoft Academic Search

The paper introduces a morphing blade for the application of wave and wind energy conversion. The most common and typical wave turbine, the Wells turbine, is symmetrical but rigid, whereas wind turbine blades are asymmetrical with some intended (adaptive) or unintended flexibility. Unlike the Wells turbine which is rigid, the morphing blade is flexible, allowing chord-wise bend from the leading

A. Beyene; J. Peffley

2007-01-01

186

Fusion EnergyFusion Energy Powering the XXI centuryPowering the XXI century  

E-print Network

the current energy sources Shortfall must be supplied by alternative sources 20th International Atomic Energy Agency, Fusion Energy Conference, Vilamoura, Portugal #12;Sources of Energy in XXISources of EnergyFusion EnergyFusion Energy Powering the XXI centuryPowering the XXI century Carlos Matos Ferreira

187

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

188

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

189

Internal wave energy radiated from a turbulent mixed layer  

NASA Astrophysics Data System (ADS)

We examine mixed-layer deepening and the generation of internal waves in stratified fluid resulting from turbulence that develops in response to an applied surface stress. In laboratory experiments the stress is applied over the breadth of a finite-length tank by a moving roughened conveyor belt. The turbulence in the shear layer is characterized using particle image velocimetry to measure the kinetic energy density. The internal waves are measured using synthetic schlieren to determine their amplitudes, frequencies, and energy density. We also perform fully nonlinear numerical simulations restricted to two dimensions but in a horizontally periodic domain. These clearly demonstrate that internal waves are generated by transient eddies at the integral length scale of turbulence and which translate with the background shear along the base of the mixed layer. In both experiments and simulations we find that the energy density of the generated waves is 1%-3% of the turbulent kinetic energy density of the turbulent layer.

Munroe, James R.; Sutherland, Bruce R.

2014-09-01

190

Optimizing Ballast Design of Wave Energy Converters Using Evolutionary Algorithms  

E-print Network

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

Tumer, Kagan

191

The Physics Classroom: Waves and Energy Transport  

NSDL National Science Digital Library

This resource from Glenbrook High School in Glenview, Illinois explains and illustrates the nature, properties and behaviors of waves. The unique nature of a standing wave is also introduced and explained. Each lesson resembles the type and extent of coverage given to that physics topic in class. The sub-lessons are accompanied by Check Your Understanding sections, providing an opportunity to assess understanding of the lesson material.

Henderson, Tom

192

High Average Power, High Energy Short Pulse Fiber Laser System  

SciTech Connect

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

Messerly, M J

2007-11-13

193

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

194

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

195

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

NASA Astrophysics Data System (ADS)

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

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

2011-06-01

196

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

197

Second Proof Work, Power, and Energy  

E-print Network

to as energy loss. fuel cell Device undergoing electrochemical cycle where electrical work is obtained during that they will be depleted in a finite time period at the current rate of consumption. power The energy rate per unit of timeSecond Proof Work, Power, and Energy M. KOSTIC Northern Illinois University DeKalb, Illinois

Kostic, Milivoje M.

198

Distinct propagating fast wave trains associated with flaring energy releases  

NASA Astrophysics Data System (ADS)

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

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

2013-06-01

199

Gauge Invariant Effective Stress-Energy Tensors for Gravitational Waves  

E-print Network

It is shown that if a generalized definition of gauge invariance is used, gauge invariant effective stress-energy tensors for gravitational waves and other gravitational perturbations can be defined in a much larger variety of circumstances than has previously been possible. In particular it is no longer necessary to average the stress-energy tensor over a region of spacetime which is larger in scale than the wavelengths of the waves and it is no longer necessary to restrict attention to high frequency gravitational waves.

Paul R. Anderson

1996-09-09

200

Power management in energy harvesting sensor networks  

Microsoft Academic Search

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

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

2007-01-01

201

Equilibrium shoreline response of a high wave energy beach  

NASA Astrophysics Data System (ADS)

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

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

2011-04-01

202

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

203

Bonneville Power Administration's Purchasing of Energy Savings  

E-print Network

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

Schick, H.

204

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

E-print Network

A set of wave equations with fractional loss operators in time and space are analyzed. It is shown that the fractional Szabo equation, the power law wave equation, and the fractional Laplacian wave equation in the causal and non-causal forms all are 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 while the former wave equations are ad hoc, heuristic equations. We show that this has consequences for use in modelling 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 preferred ones.

Holm, Sverre

2013-01-01

205

Electron trapping in shear Alfvén waves that power the aurora.  

PubMed

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 Alfvén waves, preventing immediate wave damping. As waves move to regions with larger v(Te)/v(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 Alfvén waves and electrons that form aurora. PMID:19257429

Watt, Clare E J; Rankin, Robert

2009-01-30

206

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

207

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

208

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

209

Nonequilibrium statistics of a reduced model for energy transfer in waves  

E-print Network

restricted range. For example, ocean surface waves are thought to be initiated by the wind at small remove energy from the wave system. For dispersive wave systems, such as surface ocean waves and inter- nal waves in the atmosphere and ocean, the conservative energy transfer occurs mostly through resonant

DeVille, Lee

210

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 above. The figure below shows the sine wave shape of a wave launched by attaching a stretched string

Robertson, William

211

Electromagnetic energy storage and power dissipation in nanostructures  

E-print Network

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

2014-01-01

212

Diode-pumped high power continuous-wave Yb:KGW laser  

Microsoft Academic Search

The development of a high-power diode-pumped continuous-wave Yb:KGW laser is reported. The laser delivered 6 W of average power at 1049 nm and was tunable between 1035 and 1076 nm with more than 1.3 W of output power.

Arkady Major; Richard Cisek; Virginijus Barzda

2006-01-01

213

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

214

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

Microsoft Academic Search

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

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

1995-01-01

215

Nuclear Power Trends Energy Economics and Sustainability  

E-print Network

Nuclear Power Trends Energy Economics and Sustainability L. H. Tsoukalas Purdue University Nuclear Nuclear Today · 439 nuclear power reactors (31 countries) · Over 12,000 years of operating experience · Nuclear reactors supply 16% of the world's electricity as base-load power (372,000 MWe of total capacity

216

Thermal energy storage for power plant applications  

Microsoft Academic Search

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

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

1990-01-01

217

The effect of radiation energy loss on shock wave propagation  

Microsoft Academic Search

The propagation of a shock wave induced by a supernova is examined, accounting for the energy loss due to thermal radiation. First order equations are derived for the distributions of velocity, density and pressure in the shock. It is shown that the energy loss causes a reduction in central pressure during the early stage of the shock. When the central

Zuhui Fan; Yunqiang Yu

1989-01-01

218

Optimal Power Flow of Multiple Energy Carriers  

Microsoft Academic Search

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

Martin Geidl; Göran Andersson

2007-01-01

219

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

220

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

221

Assessing ocean wave energy potential and microseisms  

NASA Astrophysics Data System (ADS)

Ocean gravity waves driven by wind and atmospheric pressure generate pressure variations on the sea floor, which are at the origin of microseism. These microseisms can be recorded as a "noise" in seismic recordings by coastal seismic stations. Two types of microseism can be recorded: primary and secondary. We are interested in the secondary microseisms, which have a frequency twice that of the causative wave and amplitude independent of the depth. From the records of coastal seismic stations, we are able to determine wave characteristics (period, height). So we need to know the sea states that allow pressure variations large enough to generate microseisms. We also need to understand how pressure variations vary in space and time and how they are linked to the sea floor. We will present the results obtained for the oceanic pressure in different cases. We will also show the conditions on different parameters to obtain pressure variation able to generate microseisms. Finally, we will study the pressure with respect to different parameters in order to illustrate our theoretical results.

Christodoulides, Paul; Pellet, Lauranne; Dias, Frédéric

2014-05-01

222

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

NASA Astrophysics Data System (ADS)

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

Freeman, Richard L.

1996-12-01

223

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

SciTech Connect

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

Freeman, R.L.

1996-08-01

224

Industrial Arts 7-9. Power/Energy: Electricity/Electronics, Power Mechanics, Power/Energy.  

ERIC Educational Resources Information Center

This guide for industrial arts grades 7-9 provides teachers with a curriculum for the subject cluster of power/energy. An "Overview" section presents the rationale, discusses how the content of the program is related to the developmental stages of the adolescent, describes the structure of the industrial arts program, and lists program goals and…

Manitoba Dept. of Education, Winnipeg.

225

Dielectric-Lined Multiwave Cerenkov Generators Producing High Power Millimeter Waves  

Microsoft Academic Search

This paper presents the concept of a Dielectric-lined Multiwave Cerenkov Generator(DMWCG) producing high power millimeter waves, which is investigated with a two and one half dimensional(\\u000a

Ting Shu; Yonggui Liu

1999-01-01

226

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

227

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

228

Two-surface wave decay: Controlling power transfer in plasma-surface interactions  

SciTech Connect

Controlled interaction of high-power pulsed electromagnetic radiation with plasma-exposed solid surfaces is a major challenge in applications spanning from electron beam accelerators in microwave electronics to pulsed laser ablation-assisted synthesis of nanomaterials. It is shown that the efficiency of such interaction can be potentially improved via an additional channel of wave power dissipation due to nonlinear excitation of two counterpropagating surface waves, resonant excitations of the plasma-solid system.

Akimov, Yu. A.; Ostrikov, K.; Azarenkov, N. A. [Complex Systems, School of Physics, University of Sydney, Sydney NSW 2006 (Australia); Institute of High Technologies, V. N. Karazin Kharkiv National University, 31 Kurchatov Avenue, Kharkiv 61108 (Ukraine); Complex Systems, School of Physics, University of Sydney, Sydney NSW 2006 (Australia); V. N. Karazin Kharkiv National University, 4 Svobody sq., Kharkiv 61077 (Ukraine)

2007-08-15

229

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

Microsoft Academic Search

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

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

2008-01-01

230

Enhanced frequency agility of high-power relativistic backward wave oscillators  

Microsoft Academic Search

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

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

1996-01-01

231

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

232

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; Yeol Lee, Kang; Hong, Jongsup; Song, Changsik; Choi, Wonjoon

2014-11-01

233

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

234

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.

235

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

236

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

NASA Astrophysics Data System (ADS)

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.; Leyser, T. B.

2010-03-01

237

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

238

Measurements of the Effects of Gravity Waves in the Middle Atmosphere Using Parametric Models of Density Fluctuations. Part II: Energy Dissipation and Eddy Diffusion  

Microsoft Academic Search

Part I of this series demonstrated the advantages of parametric models in estimating the gravity wave spectrum from density fluctuation measurements using a large power-aperture-product Rayleigh-scatter lidar. The spectra calculated using the parametric models are now used to estimate energy dissipation due to gravity waves. Energy dissipation for an individual wave in the spectrum is also estimated using Prony's method,

R. J. Sica

1999-01-01

239

Laser Fusion Energy The High Average Power  

E-print Network

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

240

Energy storage for the electric power industry  

Microsoft Academic Search

The following energy storage systems for leveling the energy demands from power companies are briefly discussed: (1) pumped hydrostorage (2) compressed air storage,(3) secondary batteries, (4) liquid hydrogen storage, and (5) flywheels. Superconducting magnetic energy storage systems are also discussed.

W. E. Keller

1973-01-01

241

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.

242

Optimizing a Hybrid Energy Storage System for a Virtual Power Plant for Improved Wind Power  

E-print Network

Optimizing a Hybrid Energy Storage System for a Virtual Power Plant for Improved Wind Power power plant. In this paper it means the combination of the hybrid energy storage system and wind power. Index Terms--Virtual power plant, hybrid energy storage, wind power, sizing energy storage 1

Teodorescu, Remus

243

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

244

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

Microsoft Academic Search

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

Ian Bailey; Jodie West; Ian Whitehead

2011-01-01

245

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

246

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

247

Energy analysis of the solar power satellite.  

PubMed

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

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

1979-08-01

248

Beamformer evaluation of low power coastal HF surface wave radar  

Microsoft Academic Search

Owing to large operational range and relatively low cost of operation coastal HF Surface Wave Radar has witnessed an increased interest in monitoring coastal territories. Using a well established sea clutter model this paper evaluates the state of art beamformer (Hamming) employed by such coastal systems. Evaluation parameters are degradation during beam scanning and target azimuth resolution in high sea

Anshu Gupta; Thomas Fickenscher

2011-01-01

249

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

250

Powerful short-pulse lasers pumped by the light of a shock wave front  

Microsoft Academic Search

Radiation of a shock wave front proved to be very powerful light source for pumping of high power lasers. Particularly, explosively pumped iodine photodissociation lasers (EPIL) are nowadays well developed type of device of multikilojoule level, rather convenient for many applications. Usually such lasers work in free running mode and generate pulses of microsecond duration. Generating short pulses of nanosecond

Gennadi A. Kirillov; V. A. Eroshenko; Gennady G. Kochemasov; Stanislav M. Kulikov; S. N. Pevny; Stanislav A. Sukharev

2000-01-01

251

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

E-print Network

Wave goodbye to flat batteries: tiny windmills could power smartphones on the go by Matthew Jarvis them on a sleeve for your smartphone," Chiao said. "When the phone is out of battery power, all you smartphones on the go | The l... 1/19/2014http://www.pcr-online.biz/news

Chiao, Jung-Chih

252

Teaching About Energy: Power of a Student  

NSDL National Science Digital Library

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

Roeder, John

2006-01-17

253

SPS Energy Conversion Power Management Workshop  

NASA Astrophysics Data System (ADS)

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.

1980-06-01

254

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

255

Temporal energy cascading in the beat wave accelerator  

NASA Astrophysics Data System (ADS)

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

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

1987-04-01

256

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

257

Power Technologies Energy Data Book - Third Edition  

SciTech Connect

This report, prepared by NREL's Energy Analysis Office, 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.

2005-04-01

258

PIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY  

E-print Network

PIEZOELECTRIC POWER SCAVENGING OF MECHANICAL VIBRATION ENERGY PIEZOELECTRIC POWER SCAVENGING and magneticand magnetic field.field. Piezoelectric Materials as Smart Material- Among the all smart materials, piezoelectric materials are of great interest, as they are commonly used as sensors, actuators and memory

Ervin, Elizabeth K.

259

Energy, environment, and advances in power electronics  

Microsoft Academic Search

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

Bimal K. Bose

2000-01-01

260

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

261

Power conversion from environmentally scavenged energy sources.  

SciTech Connect

As the power requirements for modern electronics continue to decrease, many devices which were once dependent on wired power are now being implemented as portable devices operating from self-contained power sources. The most prominent source of portable power is the electrochemical battery, which converts chemical energy into electricity. However, long lasting batteries require large amounts of space for chemical storage, and inevitably require replacement when the chemical reaction no longer takes place. There are many transducers and scavenging energy sources (SES) that are able to exploit their environment to generate low levels of electrical power over a long-term time period, including photovoltaic cells, thermoelectric generators, thermionic generators, and kinetic/piezoelectric power generators. This generated power is sustainable as long as specific environmental conditions exist and also does not require the large volume of a long lifetime battery. In addition to the required voltage generation, stable power conversion requires excess energy to be efficiently stored in an ultracapacitor or similar device and monitoring control algorithms to be implemented, while computer modeling and simulation can be used to complement experimental testing. However, building an efficient and stable power source scavenged from a varying input source is challenging.

Druxman, Lee Daniel

2007-09-01

262

Development of a Wireless Control and Monitoring System for Wave Energy Converters  

E-print Network

systems developed at Florida Institute of Technology (Florida Tech). Index Terms--ocean energy, wave on earth. Energy is stored partly in the form of kinetic energy from the motion of waves and currents of wave energy converters (WECs). II. BACKGROUND The Ocean Engineering Department at Florida Institute

Wood, Stephen L.

263

The Energy Flux of Internal Gravity Waves in the Lower Solar Thomas Straus1  

E-print Network

, can support and propagate gravity waves. On Earth these waves, which can transport energy and momentumThe Energy Flux of Internal Gravity Waves in the Lower Solar Atmosphere Thomas Straus1 , Bernhard climate. Gravity waves also play a pivotal role in planetary sciences (e.g. Young et al. 1997) and modern

264

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

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

265

Forecasting ocean wave energy: Tests of time-series models  

Microsoft Academic Search

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

Gordon Reikard

2009-01-01

266

Particle and Wave Energy Transport During Magnetic Reconnection  

NASA Astrophysics Data System (ADS)

A fundamental issue in magnetic reconnection concerns the magnetic energy stored in a reversed-field configuration: how much magnetic energy is lost as spontaneous reconnection develops and where does it go? This question is addressed using implicit 2-D PIC simulations together with the kinetic theory of energy transport of both waves and particles. The primary initial condition in these studies is a Harris equilibrium with a small guide field and background particles. The decrease in time of the integrated magnetic energy density is associated with an almost equal increase in time of the integrated ion energy density. Electrons receive only a small fraction of the initial free energy but electron phase space holes appear to play a role in the production of electromagnetic waves over a large region of the simulation box. The spatial transport of particle and field energies is studied at a late time. The dominant Poynting flux transports magnetic energy across the magnetic flux pile-up region, and is associated with the reconnection E-field. A weaker but faster Poynting flux on the separatrices is associated with the Hall electric and magnetic fields, EH and BH. The ion energy density flux and its components (bulk flow energy, enthalpy flux and heat flux) are analyzed and compared with the Poynting flux for both Harris and non-Harris initial conditions. ---Research supported by NASA and NSF

Goldman, M. V.; Newman, D. L.; Lapenta, G.; Markidis, S.; Gosling, J. T.; Andersson, L.; Eriksson, S.

2012-12-01

267

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

268

Energy conserving electrical power control circuit  

SciTech Connect

An energy conserving circuit for controlling supply of electrical power to various loads such as a street lamp or a hot water heater comprises a photoelectric device for starting a timer when a change from daylight to dark is sensed at sundown, and a load power control responsive to the timer to switch between power-off and power-on states. With a street lamp the timer and power control means are connected to switch the power control means to power-on state at the beginning of the delay period at sundown and later, well before sunrise, to switch to power-off state. In the case of a household hot water heater the switching of the power control to power-on state is delayed until the peak demand hours have ended after sundown. The photoelectric device will normally cause the power control to switch to poweroff state at sunrise. But a second timer may be added which is responsive to the photoelectric device to start a second timing period ending after normal sunrise so that switching to power-off will occur if the photoelectric device does not or cannot respond to sunrise.

Grady, J.K.

1982-12-07

269

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

270

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

Microsoft Academic Search

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

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

2008-01-01

271

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

Microsoft Academic Search

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

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

2004-01-01

272

Wave-powered desalination: resource assessment and review of technology  

Microsoft Academic Search

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

P. A. Davies

2005-01-01

273

The power of thermionic energy conversion  

NASA Astrophysics Data System (ADS)

Thermionic energy conversion to generate electric power at high operating temperatures to enable space missions requiring specific power sources to meet their power and propulsion needs is discussed. Thermionic energy conversion is one of several technologies vying to satisfy the requirements of future lunar and Martian exploration missions. The specific power for thermionic nuclear space power systems ranges from 10 W/kg at 10 kWe to about 100 W/kg at 2 MWe. Based on independent studies, it was determined that the U.S. would significantly benefit by making the thermionic reactor technology of the former Soviet Union available for future military, civil, and commercial space mission. The fiber-reinforced creep-resistant thermionic emitter electrode concept, as well as calculated lifetimes for emitter electrodes reinforced with fiber, and calculated temperature distributions near the thermionic fuel element fuel-lead region interface, are illustrated.

Ramalingam, Mysore L.; Young, Timothy J.

1993-09-01

274

Power and energy requirements for electromagnetic launchers  

NASA Astrophysics Data System (ADS)

A large data base exists covering almost all aspects of the requirements for the successful development of electromagnetic launchers. To extend the use of electromagnetic launchers to the limits of technology for such exotic applications as hypervelocity weaponry or space launch systems, it is useful to examine the energy and power requirements for such uses. One way to do this is to purposely neglect all system losses in order to determine minimum power and energy requirements. Actual power requirements will most likely be higher by at least a factor of three. Calculations are presented for minimum power requirements, launch acceleration time, projectile kinetic energy, and projectile inertial force as a function of projectile mass, projectile terminal velocity, and the length of the launch tube. Results of these calculations are presented.

Lottes, P. A.; Holtz, R. E.; Uherka, K. L.

275

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

276

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

277

Nuclear power: an essential energy. [Conference paper  

Microsoft Academic Search

Dr. Agnew notes that the public fails to remember that the electric utilities and equipment manufacturers did not invent nuclear energy; they only choose whether or not to use it to generate power. The effort to regain world leadership in nuclear energy will require recognizing that the rest of the world needs it too. Opposition to the use of nuclear

Agnew

1980-01-01

278

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.

279

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

280

Energy $ Savings From Power Capacitors  

E-print Network

.. ~ Reactor Size (3 kVA) Figure 7. Current limiting reactor full load annual load loss. 853 ESL-IE-82-04-153 Proceedings from the Fourth Industrial Energy Technology Conference, Houston, TX, April 4-7, 1982 100 0.2 100 0.1 10 Capacitor Installation... .. ~ Reactor Size (3 kVA) Figure 7. Current limiting reactor full load annual load loss. 853 ESL-IE-82-04-153 Proceedings from the Fourth Industrial Energy Technology Conference, Houston, TX, April 4-7, 1982 100 0.2 100 0.1 10 Capacitor Installation...

Harder, J. E.

1982-01-01

281

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

282

Power laws and STM image of standing wave of the topological surface states  

Microsoft Academic Search

We have theoretically and experimentally studied the quasiparticle interference pattern caused by scattering off the step edges of topological surface states in Bi2Te3 and Bi2Se3. We propose a general formalism to identify the power law that governs the decaying spatial oscillations of standing wave of the quasiparticle. With strong hexagonal warping of the surface states in Bi2Te3, the standing wave

Bang-Fen Zhu; Jing Wang; Wei Li; Peng Cheng; Canli Song; Tong Zhang; Xi Chen; Xucun Ma; Ke He; Jin-Feng Jia; Qi-Kun Xue

2011-01-01

283

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

284

Energy storage for a competitive power market  

SciTech Connect

This article discusses briefly the status of energy storage technologies and explores opportunities for their application in the rapidly changing US energy marketplace. Traditionally, electric utility energy storage has been used to store low-priced purchased or generated electric energy for later sale or use when energy cost would otherwise be much higher. But deregulation and restructuring in the electric industry, coupled with an expanding portfolio of storage alternatives, may lead to many new opportunities for energy storage, especially within the energy distribution infrastructure, and for maintaining or providing power quality at large customer sites. Small, modular, robust energy storage technologies could be used to solve a range of energy supply and infrastructure-related needs. This article provides quantitative evidence of utility-related storage status, benefits, and opportunities.

Schoenung, S.M. [Longitude 122 West, Inc., Menlo Park, CA (United States)] [Longitude 122 West, Inc., Menlo Park, CA (United States); Eyer, J.M.; Iannucci, J.J.; Horgan, S.A. [Distributed Utility Associates, San Ramon, CA (United States)] [Distributed Utility Associates, San Ramon, CA (United States)

1996-12-31

285

Characterizing magnetospheric ULF wave power due to direct driving by the solar wind  

NASA Astrophysics Data System (ADS)

Magnetospheric ULF waves at (mHz) frequencies are an efficient driver of radial transport among the relativistic electrons comprising the outer zone radiation belts. In this effort we use global MHD simulations of the magnetosphere/solar wind interaction to probe the effect of shear waves and pressure fluctuations in the solar wind in producing Pc-5 ULF power in the inner magnetosphere and radiation belts, with the goal of creating numerical or analytic mapping functions between solar wind conditions and ULF activity. This ULF activity may then be used to characterize radial transport rates in the radiation belts in terms of relevant diffusion coefficients. We investigate the feasibility of empirically modeling magnetospheric ULF wave activity as it relates to ULF power in the solar wind by comparing the ULF power distribution in the magnetosphere during events driven by observed solar wind conditions.

Elkington, Scot; Claudepierre, Seth; Chan, Anthony; Wiltberger, Michael

286

Sound power spectrum and wave drag of a propeller in flight  

NASA Astrophysics Data System (ADS)

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.

1989-04-01

287

Energy storage options for space power  

NASA Astrophysics Data System (ADS)

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

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

288

Wecpos - Wave Energy Coastal Protection Oscillating System: A Numerical Assessment  

NASA Astrophysics Data System (ADS)

In recent years, the interest in developing new technologies to produce energy with low environmental impact by using renewable sources has grown exponentially all over the world. In this context, the experiences made to derive electricity from the sea (currents, waves, etc.) are of particular interest. At the moment, due to the many existing experiments completed or still in progress, it is quite impossible explain what has been obtained but it is worth mentioning the EMEC, which summarizes the major projects in the world. Another important environmental aspect, also related to the maritime field, is the coastal protection from the sea waves. Even in this field, since many years, the structural and non-structural solutions which can counteract this phenomenon are analyzed, in order to cause the least possible damage to the environment. The studies in development by the researchers of the University of Salerno are based on these two aspect previously presented. Considering the technologies currently available, a submerged system has been designed, WECPOS (Wave Energy Coastal Protection Oscillating System), to be located on relatively shallow depths, to can be used simultaneously for both electricity generation and for the coastal protection using the oscillating motion of the water particles. The single element constituting the system is realized by a fixed base and three movable panels that can fluctuate in a fixed angle. The waves interact with the panels generating an alternative motion which can be exploited to produce electricity. At the same time, the constraint movement imposed for the rotation of the panels is a barrier to the wave propagation phenomena, triggering the breaking in the downstream part of the device. So the wave energy will be dissipated obtaining a positive effect for the coastal protection. Currently, the efficiency and effectiveness of the system (WECPOS single module) has been studied by using numerical models. Using the FLOW-3D® software it has been possible to evaluate the hydrodynamic interactions that occur between a regular wave, with different height and period characteristics. The RANS equations, coupled with the RNG turbulence model, have been integrated on a three-dimensional channel (90.0 x 6.0 x 8.0 m), using a numerical domain made of two mesh blocks: a general one containing the entire domain (cells size 0.30 cm) and the localized one on the device (cells size 0.10 cm). With the results, by assessing the rotational angle, angular velocity, hydraulic torque of the individual panel it has been possible to estimate the potential energy production. A Matlab/Simulink model has been built to estimate the production of electric energy by means of an oleodynamic system consisting of a piston and a turbine coupled with an electric generator. About the coastal protection, by estimating some characteristic parameters of the wave motion (zero-moment wave height Hmo, transmission coefficient Kt and the average free surface elevation), the behaviour of the WECPOS device has been analyzed for its ability in wave energy dissipation.

Dentale, Fabio; Pugliese Carratelli, Eugenio; Rzzo, Gianfranco; Arsie, Ivan; Davide Russo, Salvatore

2010-05-01

289

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

NASA Astrophysics Data System (ADS)

A novel discrete model (D model) is presented describing nonlinear wave interactions in systems with small and moderate nonlinearity under narrow frequency band excitation. It integrates in a single theoretical frame two mechanisms of energy transport between modes, namely, intermittency and energy cascade, and gives the conditions under which each regime will take place. Conditions for the formation of a cascade, cascade direction, conditions for cascade termination, etc., are given and depend strongly on the choice of excitation parameters. The energy spectra of a cascade may be computed, yielding discrete and continuous energy spectra. The model does not require statistical assumptions, as all effects are derived from the interaction of distinct modes. In the example given—surface water waves with dispersion function ?2=gk and small nonlinearity—the D model predicts asymmetrical growth of side-bands for Benjamin-Feir instability, while the transition from discrete to continuous energy spectrum, excitation parameters properly chosen, yields the saturated Phillips’ power spectrum ˜g2?-5. The D model can be applied to the experimental and theoretical study of numerous wave systems appearing in hydrodynamics, nonlinear optics, electrodynamics, plasma, convection theory, etc.

Kartashova, Elena

2012-10-01

290

Microwave power coupling in a surface wave excited plasma  

E-print Network

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; Kousaka, Hiroyuki

2014-01-01

291

A New Methodology for Frequency Domain Analysis of Wave Energy Converters with Periodically Varying Physical Parameters  

NASA Astrophysics Data System (ADS)

Within a wave energy converter's operational bandwidth, device operation tends to be optimal in converting mechanical energy into a more useful form at an incident wave period that is proximal to that of a power-producing mode of motion. Point absorbers, a particular classification of wave energy converters, tend to have a relative narrow optimal bandwidth. When not operating within the narrow optimal bandwidth, a point absorber's response and efficiency is attenuated. Given the wide range of sea-states that can be expected during a point absorber's operational life, these devices require a means to adjust, or control, their natural response to maximize the amount of energy absorbed in the large population of non-optimal conditions. In the field of wave energy research, there is considerable interest in the use of non-linear control techniques to this end. Non-linear control techniques introduce time-varying and state dependent control parameters into the point absorber motion equations, which usually motivates a computationally expensive numerical integration to determine the response of the device - important metrics such as gross converted power and relative travels of the device's pieces are extracted through post processing of the time series data. As an alternative, the work presented in this thesis was based on a closed form perturbation based approach for analysis of the response of a device with periodically-varying control parameters, subject to regular wave forcing, in the frequency domain. The proposed perturbation based method provides significant savings in computational time and enables the device's response to be represented in a closed form manner with a relatively small number of solution components - each component is comprised of a complex amplitude and oscillation frequency. This representation of the solution was found to be very concise and descriptive, and to lend itself to the calculation of gross absorbed power and travel constraint violations, making it extremely useful in the automated design optimization process; the methodology allows large number of design iterations, including both physical design and control variables, to be evaluated and conclusively compared. In the development of the perturbation method, it was discovered that the device's motion response can be calculated from an infinite series of second order ordinary differential equations that can be truncated without destroying the solution accuracy. It was found that the response amplitude operator for the generic form of a solution component provides a means to gauge the device's response to a given wave input and control parameter variation, including a gauge of the solution process stability. It is unclear as of yet if this is physical, a result of the solution process, or both. However, for a given control parameter set resulting in an unstable solution, the instability was shown to be, at least in part, a result of the device's dynamics. If the stability concerns can be addressed through additional constraints and updates to the wave energy converter hydrodynamic parameters, the methodology will expand on the commonly accepted boundaries for wave energy converter frequency-domain analysis methods and be of much practical importance in the evaluation of control techniques in the field of wave energy converter technology.

Mosher, Mark

292

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

PubMed

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

Chen, Yun; Huang, Wei; Constantini, Shlomi

2012-01-01

293

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

294

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

PubMed

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

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

2012-05-01

295

High-power and wavelength-tunable traveling-wave semiconductor ring laser  

E-print Network

HIGH-POWER AND WAVELENGTH-TUNABLE TRAVELING-WAVE SEMICONDUCTOR RING LASER A Thesis EN TITUS PENG Submitted to the Office of Graduate Studies of Texas ARM University in partial fulfillment of the requirement for the degree of MASTER OF SCIENCE... May 1991 Major Subject: Electrical Engineering HIGH-POWER AND WAVELENGTH-TUNABLE TRAVELING-WAVE SEMICONDUCTOR RING LASER A Thesis by EN TITUS PENG Approved as to style and content by: Ch' B. Su (Chair of Committee) 0, 4 Ohannes E n yan...

Peng, En Titus

2012-06-07

296

Power management circuit for resonant energy harvesters  

NASA Astrophysics Data System (ADS)

This paper deals with the design of the power management circuit for the vibration generator developed in the frame of the European WISE project and its testing in the connection with the generator and the dynamic load simulating the real load. This generator is used as an autonomous energy source for wireless sensor applications. It can be used for example in the aeronautic, automotive and many other applications. The generator output power analysis was based on the vibration spectrum measured on the helicopter engine, provided by the consortium EADS, EUROCOPTER, DASSAULT AVIATION - 6.RP -WIreless SEnsing (WISE) project. This spectrum shows very unstable vibration levels. It was done the statistical analysis of these vibration levels and it was shown that there is a need of the power management circuit, which can provide a stable output voltage for the supplied circuit and if there is a need it can store an immediately unusable generated energy. The generator can't be used as the only energy source for the sensor circuit, because there are not any vibrations when for example a motor is stopped. In these periods and in the time of low vibration levels the circuit must be supplied from battery. The power management circuit described in this paper fulfills these requirements. It has two power inputs - the battery and the generator. It can switch between them at certain defined generator output levels by the threshold detector. Also when there is too much of the generated power, it can store the extra energy in the storage for the later usage. The storage device is the advanced capacitor. The advanced capacitor is a device containing three capacitors. These capacitors are connected (and charged) sequentially so the increasing capacity is provided. The developed power management was tested in the connection with the real vibration generator raised by stable vibration levels and the dynamic load simulating the real sensor in the main operation stages - sampling and data transmitting. It was shown that the generator with output power of 8mW@0,3GRMS with generator weight of 140g together with the described power management circuit can save about 50% of battery energy with the mentioned vibration spectrum. The generator used for the testing was improved, so it is more sensitive and also the sensor power requirements were decreased, so now it can be saved up to 100% battery energy during the generator operation. Also the power management circuit is still refined.

Jirku, Tomas; Steinbauer, Miloslav; Kluge, Martin

2009-05-01

297

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

298

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

299

Estimation of Radiated Seismic Energy from Teleseismic P Waves  

NASA Astrophysics Data System (ADS)

Earthquake radiated energy is a fundamental parameter for understanding source physics. Using teleseismic waveforms, we can estimate the radiated energy for a wide range of focal mechanisms and tectonic setting. We are especially interested in studying the apparent stress (rigidity multiplied by the ratio of radiated energy to seismic moment) of strike-slip earthquakes in the oceanic lithosphere, for which there are often high reported values (Choy and McGarr, 2002). Estimates of radiated energy from teleseismic P waves can be unstable, because take-off angles from the source are often close to nodes in the focal mechanisms, which can cause large variations in the estimated values of the apparent stress. In this study, we use only P waves for the teleseismic waveform, because of the strong attenuation of teleseismic S waves and interference with other phases. We use data recorded by teleseismic stations (epicentral distances of 30 to 90deg) recorded on the GSN network and focal mechanisms published by USGS and Global CMT Project. For the teleseismic waveforms, we need to account for the radiation pattern of the direct P and depth phase, pP and sP (Boatwright and Choy, 1986). For strike-slip events with where many data are close to nodes in the focal mechanisms, this is a large and often unstable correction. We use an improved method which takes into account a range of values for the strike, dip and rake angles. Also, we use station corrections determined from a selected set of well determined events. We show the result of estimated radiated seismic energy for 188 recent earthquakes (>Mw 7.0, since 2000 ). We discuss the differences of the radiated energy as a function of focal mechanisms, and oceanic/continental sources. Fig. Radiated seismic energy and correction for radiation pattern calculated using a range of focal mechanisms.

Kiuchi, R.; Mori, J. J.

2013-12-01

300

Horizontal displacements contribution to tsunami wave energy balance  

E-print Network

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

Dutykh, Denys; Chubarov, Leonid; Shokin, Yuriy

2010-01-01

301

Photon Energy Upshift by Gravitational Waves a Possible Source of X-ray Bursts  

NASA Astrophysics Data System (ADS)

For events as violent as the core-collapse of stars and merger of blackholes, one of the largest portions of energy released is throughgravitational radiation. This leads to a number o important issues. Forinstance, does there exist any mechanism by which some of the GW energy maybe transferred to photons and other particles? If such a mechanismexists, how relevant is it for energetic events like gamma ray bursts(GRBs). Here we consider the propagation of light from an isolated sourcethat emits gravitational waves .The eikonal approach is employed todetermine the transfer of energy from the gravitational to electromagneticradiation. It is found that, a significant upshift of photon energy canoccur according to a power-law buildup over the radial distance. Thissomewhat surprising effect may be responsible for some of the unexplainedhigh energy phenomena in the cosmos involving gamma rays or other forms ofastro-particles.

Bingham; Mendoca; Wang, H.-T.

2006-02-01

302

Power management for energy harvesting wireless sensors  

NASA Astrophysics Data System (ADS)

The objective of this work was to demonstrate smart wireless sensing nodes capable of operation at extremely low power levels. These systems were designed to be compatible with energy harvesting systems using piezoelectric materials and/or solar cells. The wireless sensing nodes included a microprocessor, on-board memory, sensing means (1000 ohm foil strain gauge), sensor signal conditioning, 2.4 GHz IEEE 802.15.4 radio transceiver, and rechargeable battery. Extremely low power consumption sleep currents combined with periodic, timed wake-up was used to minimize the average power consumption. Furthermore, we deployed pulsed sensor excitation and microprocessor power control of the signal conditioning elements to minimize the sensors" average contribution to power draw. By sleeping in between samples, we were able to demonstrate extremely low average power consumption. At 10 Hz, current consumption was 300 microamps at 3 VDC (900 microwatts); at 5 Hz: 400 microwatts, at 1 Hz: 90 microwatts. When the RF stage was not used, but data were logged to memory, consumption was further reduced. Piezoelectric strain energy harvesting systems delivered ~2000 microwatts under low level vibration conditions. Output power levels were also measured from two miniature solar cells; which provided a wide range of output power (~100 to 1400 microwatts), depending on the light type & distance from the source. In summary, system power consumption may be reduced by: 1) removing the load from the energy harvesting & storage elements while charging, 2) by using sleep modes in between samples, 3) pulsing excitation to the sensing and signal conditioning elements in between samples, and 4) by recording and/or averaging, rather than frequently transmitting, sensor data.

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

2005-05-01

303

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

Microsoft Academic Search

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

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

2006-01-01

304

Energy space entanglement spectrum of pairing models with s-wave and p-wave symmetry  

NASA Astrophysics Data System (ADS)

We study the entanglement between blocks of energy levels in 1D models for s-wave and p-wave superconductivity. The ground state entanglement entropy and entanglement spectrum (ES) of a block of ? levels around the Fermi point is obtained and related to its physical properties. In the superconducting phase at large coupling, the maximal entropy grows with the number of levels L as 1/2ln(L). The number of levels presenting maximal entanglement is shown to estimate the number of Cooper pairs involved in pairing correlations. Moreover, the properties of the ES signal the presence of the Read-Green quantum phase transition in the p +ip model, and of the Moore-Read line, which is difficult to characterize. This work establishes a link between physical properties of superconducting phases and quantum entanglement.

Rodríguez-Laguna, Javier; Berganza, Miguel Ibáñez; Sierra, Germán

2014-07-01

305

OWC wave energy devices with air flow control  

Microsoft Academic Search

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

A. F. de O. Falcão; P. A. P. Justino

1999-01-01

306

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

NASA Astrophysics Data System (ADS)

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

Yildiz, Faruk

307

Wave equations for determining energy-level gaps of quantum systems  

E-print Network

An differential equation for wave functions is proposed, which is equivalent to Schr\\"{o}dinger's wave equation and can be used to determine energy-level gaps of quantum systems. Contrary to Schr\\"{o}dinger's wave equation, this equation is on `bipartite' wave functions. It is shown that those `bipartite' wave functions satisfy all the basic properties of Schr\\"{o}dinger's wave functions. Further, it is argued that `bipartite' wave functions can present a mathematical expression of wave-particle duality. This provides an alternative approach to the mathematical formalism of quantum mechanics.

Zeqian Chen

2006-04-12

308

Development of a high power 12GHz PPM focused traveling wave tube  

NASA Technical Reports Server (NTRS)

An analytical and experimental program to demonstrate the technical feasibility of a high efficiency coupled cavity traveling wave tube with periodic permanent magnetic focusing operating at 12.06 GHz, with 1 to 2 kilowatts CW power is described. Such a tube would ultimately be used for broadcasting power transmission from a satellite. The electron gun was designed to be demountable with a replaceable cathode, and the tube to be operable in a bakeable vacuum chamber with its collector replaced by a collector. Therefore, the high efficiency design was concerned with the slow wave structure only, utilizing velocity resynchronization. A special adapter was designed which incorporated an electromagnet refocusing section and a collector baseplate to facilitate testing the collector. CW output power of 1000 watts yielding 21.5% electronic efficiency was demonstrated, with a minimum output power of 525 watts across the specified 160 MHz bandwidth.

Lewis, R.

1975-01-01

309

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

310

Using generalized PowerFlux methods to estimate the parameters of periodic gravitational waves  

Microsoft Academic Search

We investigate methods to estimate the parameters of the gravitational-wave signal from a spinning neutron star using Fourier-transformed segments of the strain response from an interferometric detector. Estimating the parameters from the power, we find generalizations of the PowerFlux method. Using simulated elliptically polarized signals injected into Gaussian noise, we apply the generalized methods to estimate the squared amplitudes of

Gregory Mendell; Karl Wette

2008-01-01

311

MPACVD-diamond windows for high-power and long-pulse millimeter wave transmission  

Microsoft Academic Search

To satisfy the electrical, thermomechanical and nuclear requirements for continuous wave (CW) millimeter (mm)-wave vacuum windows for electron cyclotron heating in thermonuclear plasma fusion energy research, water-edge-cooled window assemblies using large synthesized diamond disks have been developed in Europe, Japan, Russia and the USA. The diamond employed in these studies has been manufactured predominantly at DeBeers Industrial Diamond Division (UK)

Manfred Thumm

2001-01-01

312

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

E-print Network

coastal erosion and significant economic impacts [Davis et al., 1993; Dolan et al., 1988; Mather et al erosion along the North Carolina coast [Dolan and Davis, 1992]. From a coastal management and planning Mode. The annual wave power at near-coastal locations is closely associated with open ocean WPI

Kossin, James P.

313

Suppression of power line harmonic interference in HF surface-wave radar  

Microsoft Academic Search

Experimental data of the Cape Bonavista High-Frequency Surface-Wave Radar (HFSWR) Facility was contaminated by power line harmonics. The harmonics modulate the radar signal (mainly sea clutter) and replicate it into the Doppler spectrum. The spectral replicas distort the noise and sea clutter statistics in the signal. It is necessary to suppress them before the statistics can be obtained. A new

Hank Leong

1992-01-01

314

Gain and continuous-wave laser power enhancement with a secondary discharge to predissociate molecular iodine  

E-print Network

molecular iodine in an electric oxygen-iodine laser G. F. Benavides,1 J. W. Zimmerman,2 B. S. Woodard,2 D. L and 38% enhancement in continuous-wave laser power on the 1315 nm transition of atomic iodine through the addition of a secondary discharge to predissociate the molecular iodine in an electric oxygen-iodine laser

Carroll, David L.

315

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

316

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

317

High-power continuous wave 690 nm AlGaInP laser-diode arrays  

Microsoft Academic Search

High-power diode laser arrays emitting at 690 nm have been developed for solid-state laser pumping. The laser diode bars (fill factor ≊0.7) have been fabricated from single quantum well AlGaInP-based heterostructures. Using silicon microchannel heatsinks, a record high 360 W\\/cm2 per emitting aperture is achieved under continuous wave operation.

J. A. Skidmore; M. A. Emanuel; R. J. Beach; W. J. Benett; B. L. Freitas; N. W. Carlson; R. W. Solarz

1995-01-01

318

Application of wave guide propagation to selection of transmitter power and frequency  

NASA Astrophysics Data System (ADS)

This paper is concerned with developing reasonable criteria for the selection of frequency and power for very low and low-frequency (VLF/LF) transmitting stations. The approach uses a wave guide model for low-frequency propagation and accounts for the variability of the ionosphere. A sample problem involving a hypothetical transmitter is described.

Ferguson, Jerry A.; Hansen, Peder M.

1992-04-01

319

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

320

Solar power satellite life-cycle energy recovery consideration  

Microsoft Academic Search

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

S. Weingartner; J. Blumenberg

1994-01-01

321

Self-similar relativistic blast waves with energy injection  

E-print Network

[abbreviated] I describe the evolution of limited duration energy injection blast waves and their transition stage, with an emphasis on the optical / X-ray plateau phase of Gamma-ray Burst (GRB) afterglows as an application. A complete fluid profile during injection including the reverse shock region is given. The transition is shown with one-dimensional simulations of radial flow to take about a sound crossing time. While energy injection is ongoing, the sideways flux of energy due to jet expansion usually lies orders of magnitude below the injected energy, causing the flow to remain approximately radial. For synchrotron emission from shock-accelerated particles, the resulting flux equations are provided for general circumburst medium structure. The relative flux between forward and reverse shock region depends on their respective magnetizations and the Lorentz factor of the inflowing matter from the source, but for typical afterglow values it is shown that emission from the reverse shock can easily dominate...

van Eerten, Hendrik

2014-01-01

322

Hydroelectric power and America's energy future  

SciTech Connect

This article discusses the debate over the merit of hydroelectric power and the part it will play in providing energy in America in the future. The environmental impact, reliability, efficiency, and regulation of hydroelectric projects are discussed with examples and references to other publications. FERC application of existing regulations in the licensing and relicensing process is also discussed.

Boxall, J.A. Jr.

1990-02-01

323

Novel Nuclear Powered Photocatalytic Energy Conversion  

Microsoft Academic Search

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

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

2005-01-01

324

Coordinated Management: Power, Performance, Energy, and Temperature  

E-print Network

Coordinated Management: Power, Performance, Energy, and Temperature Heather Hanson Stephen W and performance. 1.1 Coordinated Management The coordinated manager's central component is a multi- criteria, and temperature. The manager will select a goal, such as "maxi- mum performance within fixed temperature

Keckler, Stephen W.

325

US Department of Energy: Concentrating Solar Power  

NSDL National Science Digital Library

This website provides an introduction to the US Department of Energy's research and developments in concentrating solar power. The site outlines the department's three main technologies and the programs goals. Links to more information about solar heating, solar lighting, and photovoltaics are also provided.

2007-09-26

326

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

327

Millimeter wave circular-electric transducers for high power uses  

NASA Astrophysics Data System (ADS)

It has been found that the gyrotron is an efficient source of high-power radiation (1 kW - 1 MW) at wavelengths less than 1 cm. The operation of the gyrotron requires the transfer of TE modes into lower modes of the same waveguide or into modes of another waveguide. The present investigation is concerned with two kinds of transducers for performing the transfers, taking into circular-electric transducers and transducers of a type employed by Marcatili (1961) to study hybrid junctions. Attention is given to the profile of a circular-electric transducer, the phase shifter utilized to control the phase difference between modes, the derivation of the S parameters for the hybrid junction, a signal flow graph, the characteristics of the tranducers, and the mode chart in a coaxial sector waveguide.

Zhang, J.-H.; Wang, H.-C.; Qian, J.-R.

1983-10-01

328

Wind power: The new energy policy 1  

NASA Astrophysics Data System (ADS)

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

1991-10-01

329

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

NASA Astrophysics Data System (ADS)

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

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

2010-05-01

330

Energy and directional signatures for plane quantized gravity waves  

NASA Astrophysics Data System (ADS)

Solutions are constructed to the quantum constraints for planar gravity (fields dependent on z and t only) in the Ashtekar complex connection formalism. A number of operators are constructed and applied to the solutions. These include the familiar ADM energy and area operators, as well as new operators sensitive to intrinsic spin and directionality (z+ct vs z-ct dependence). The directionality operators are quantum analogs of the classical constraints proposed for unidirectional plane waves by Bondi, Pirani, and Robinson (BPR). It is argued that the quantum BPR constraints will predict unidirectionality reliably only for solutions which are semiclassical in a certain sense. Schwinger has proved that a unidirectional plane electromagnetic wave is stable, even in the presence of the quantum zero point fluctuations of the vacuum. A preliminary calculation (preliminary, because not regulated) indicates that the corresponding gravitational wave may be destabilized by zero point fluctuations. The ADM energy and area operators are likely to have imaginary eigenvalues, unless one either shifts to a real connection, or allows the connection to occur other than in a holonomy. In classical theory, the area can evolve to zero. A quantum mechanical mechanism is proposed which would prevent this collapse.

Neville, Donald E.

1998-01-01

331

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

SciTech Connect

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

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

2009-01-01

332

Nuclear Power and the World's Energy Requirements  

E-print Network

The global requirements for energy are increasing rapidly as the global population increases and the under-developed nations become more advanced. The traditional fuels used in their traditional ways will become increasingly unable to meet the demand. The need for a review of the energy sources available is paramount, although the subsequent need to develop a realistic strategy to deal with all local and global energy requirements is almost as important. Here attention will be restricted to examining some of the claims and problems of using nuclear power to attempt to solve this major question.

V. Castellano; R. F. Evans; J. Dunning-Davies

2004-06-10

333

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

334

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

335

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

NASA Astrophysics Data System (ADS)

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

Wang, Bin; Komurasaki, Kimiya; Arakawa, Yoshihiro

2013-09-01

336

Economical considerations of renewable electric energy production—especially development of wave energy  

Microsoft Academic Search

Investments in renewable energy plants normally only take standard economic key figures into account, such as installed rated power, the market price of energy and the interest rate. The authors propose that the degree of utilisation, i.e. the ratio of yearly produced energy in the installation to the installed power, must be included due to its significant impact on the

Mats Leijon; Hans Bernhoff; Marcus Berg; Olov Ågren

2003-01-01

337

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

338

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

NASA Astrophysics Data System (ADS)

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

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

2013-03-01

339

Unbundling of electric power and energy services  

SciTech Connect

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

Keith, D.M. [Keith and Associates, Ltd., Stilwell, KS (United States); Lewis, B.R. [UtiliCorp United Inc., Kansas City, MO (United States)

1996-12-31

340

Piezoelectric capacitive power generator from vibration energy  

NASA Astrophysics Data System (ADS)

A vibration-powered micro-power-generator has been presented in this paper, which has integrated two different energy harvesting mechanisms, e.g., Capacitive and Piezoelectric Mechanisms. The periodic vibration of the mass on movable electrode causes the variation of the capacitance, and the strain in the piezoelectric film. These two mechanisms can harvest the vibration energy and generate current in the output circuit. By using two different metals with large difference in working function as the two electrodes of the capacitor, our design, the combination of these two different scavenge mechanisms, can overcome the dependence of the traditional capacitive converter on the separate voltage source and improve the efficiency of power conversion. The volume of the designed device is less than 0.8 cm 3. The simulated results reveal that this energy converter can provide an average output power of 82.21?W at an external vibration with a frequency of 111.4 Hz and amplitude of 0.2g.

Zhang, Yangjian; Li, Lin; San, Haisheng; Chen, Xuyuan

2008-03-01

341

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

342

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

343

Multifunctional power electronic converters for flexible energy management in shipboard power systems  

Microsoft Academic Search

Multifunctional power electronic converters are used in shipboard power systems for various needs including energy conversion from one form to the other, power generation, and transmission. The ability to do more functions with a single power electronic converter is desired in shipboard power systems, especially when there is an inadequate energy management resource, or unexpected demand that may appear as

Konstantin Borisov

2008-01-01

344

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

345

A power spectral analysis of turbulence associated with interplanetary shock waves  

NASA Astrophysics Data System (ADS)

We calculate the power spectra densities of magnetic field fluctuations associated with interplanetary shock waves at 1AU, utilizing in-situ magnetic field measurements from spacecraft ACE and Wind. We derive related quantities both upstream and downstream of a shock as a function of time/distance away from the shock passage. We present results for a few events that exhibit clear upstream enhanced wave activity. We show that mostly they are of Alfvénic nature and confined within certain distance upstream. We also present a preliminary analysis of turbulence-particle interaction based on spectral analysis results. Implications of such analysis to turbulence transport models are also discussed.

Hu, Qiang; Zank, Gary P.; Li, Gang; Ao, Xianzhi

2013-06-01

346

Energy-Dependent Gamma-Ray Burst Peak Durations and Blast-Wave Deceleration  

E-print Network

Temporal analyses of the prompt gamma-ray and X-ray light curves of gamma-ray bursts reveal a tendency for the burst pulse time scales to increase with decreasing energy. For an ensemble of BATSE bursts, Fenimore et al. (1995) show that the energy dependence of burst peak durations can be represented by $\\Delta t \\propto E^{-\\gamma}$ with $\\gamma \\simeq 0.4$--0.45. This power-law dependence has led to the suggestion that this effect is due to radiative processes, most notably synchrotron cooling of the non-thermal particles which produce the radiation. Here we show that a similar power-law dependence occurs, under certain assumptions, in the context of the blast-wave model and is a consequence of the deceleration of the blast-wave. This effect will obtain whether or not synchrotron cooling is important, but different degrees of cooling will cause variations in the energy dependence of the peak durations.

James Chiang

1998-05-22

347

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

NASA Technical Reports Server (NTRS)

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

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

1993-01-01

348

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

NASA Astrophysics Data System (ADS)

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

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

2008-11-01

349

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

350

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

351

Multimessenger astrophysics: When gravitational waves meet high energy neutrinos  

NASA Astrophysics Data System (ADS)

With recent development of experimental techniques that have opened new windows of observation of the cosmic radiation in all its components, multi-messenger astronomy is entering an exciting era. Many astrophysical sources and cataclysmic cosmic events with burst activity can be plausible sources of concomitant gravitational waves (GWs) and high-energy neutrinos (HENs). Such messengers could reveal hidden and new sources that are not observed by conventional photon astronomy, in particular at high energy. Requiring consistency between GW and HEN detection channels enables new searches and a detection would yield significant additional information about the common source. We present the results of the first search for gravitational wave bursts associated with high energy neutrino triggers, detected by the underwater neutrino telescope ANTARES in its 5 line configuration, during the fifth LIGO science run and first Virgo science run. No evidence for coincident events was found. We place a lower limit on the distance to GW sources associated with every HEN trigger. We are able to rule out the existence of coalescing binary neutron star systems and black hole-neutron star systems up to distances that are typically 5 Mpc and 10 Mpc respectively.

Di Palma, Irene

2014-04-01

352

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

353

Quasi-optical solid-state power combining for millimeter-wave active seeker applications  

SciTech Connect

Consideration is given to quasi-optical power combining techniques, state-of-the-art demonstrated performance, and system issues as they apply to endoatmospheric homing seeker insertion. Quasi-optical power combining is based on combining microwave and millimeter-wave solid-state device power in space through the use of antennas and lenses. It is concluded that quasi-optical power combining meets the severe electrical requirements and packaging constraints of active MMW seekers for endoatmospheric hit-to-kill missiles. The approach provides the possibility of wafer-scale integration of major components for low cost production and offers high reliability. Critical issues include thermal loading and system integration, which must be resolved before the quasi-optical power combining technology will be applied to an active MMW seeker. 18 refs.

Halladay, R.H.; Terrill, S.D.; Bowling, D.R.; Gagnon, D.R. (U.S. Army, Missile Command, Redstone Arsenal, AL (United States) U.S. Navy, Naval Air Warfare Center, China Lake, CA (United States))

1992-05-01

354

Quasi-optical solid-state power combining for millimeter-wave active seeker applications  

NASA Astrophysics Data System (ADS)

Consideration is given to quasi-optical power combining techniques, state-of-the-art demonstrated performance, and system issues as they apply to endoatmospheric homing seeker insertion. Quasi-optical power combining is based on combining microwave and millimeter-wave solid-state device power in space through the use of antennas and lenses. It is concluded that quasi-optical power combining meets the severe electrical requirements and packaging constraints of active MMW seekers for endoatmospheric hit-to-kill missiles. The approach provides the possibility of wafer-scale integration of major components for low cost production and offers high reliability. Critical issues include thermal loading and system integration, which must be resolved before the quasi-optical power combining technology will be applied to an active MMW seeker.

Halladay, R. H.; Terrill, S. D.; Bowling, D. R.; Gagnon, D. R.

1992-05-01

355

Gain and continuous-wave laser power enhancement with a multiple discharge electric oxygen-iodine laser  

NASA Astrophysics Data System (ADS)

Herein the authors report on the demonstration of a 70% enhancement in gain and 98% enhancement in continuous-wave laser power on the 1315nm transition of atomic iodine via an increase in flow rates and pressure using multiple discharges in an electric oxygen-iodine laser. O2(a?1) is produced by two parallel radio-frequency-excited electric discharges sustained in an O2-He-NO gas mixture, a secondary discharge predissociated the molecular iodine, and I(P1/22) is then pumped using energy transferred from O2(a?1). A gain of 0.17%cm-1 was obtained and the total laser output power was 12.3W.

Zimmerman, J. W.; Woodard, B. S.; Benavides, G. F.; Carroll, D. L.; Verdeyen, J. T.; Palla, A. D.; Solomon, W. C.

2008-06-01

356

Sensorless Sinusoidal Wave Drive for Control of Power Factor of PM Motor by Detection of Inverter Bus Current  

NASA Astrophysics Data System (ADS)

Permanent-magnet synchronous motors (PMSMs) with a sinusoidal back EMF are widely used in domestic appliances for reduction of acoustic noises and energy consumption. PMSMs are generally controlled with a sinusoidal waveform current. Typically, PMSMs are controlled by vector-controlled sinusoidal drives, which require powerful computational resources. Hence, simpler sinusoidal wave drives such as V/f drives, which control the phase difference between the voltage and the current (power factor of PM Motor) have been proposed for controlling PMSMs. This paper presents a new method that does not require current sensors but can be used to estimate the phase difference by sampling the voltage of the shunt register, which is used to detect the over current supplied to the inverter. This method enables detection of current and accurate estimation and appropriate control of the phase difference. Using this method, we could control the phase difference and achieve high efficiency, cost reduction, and high reliability.

Matsushita, Motoshi; Kameyama, Hiroyuki; Ikeboh, Yasuhiro; Morimoto, Shigeo

357

Spectral Cascade and Energy Dissipation in Kinetic Alfven Wave Turbulence  

E-print Network

parallel gyrokinetic particle simulation. The simulation observes a magnetic energy spectrum with a power and astrophysical plasmas. The fluctuations in the magnetic field and the plasma velocity are often highly for collisionless plasma heating. 1. Introduction Random magnetic fluctuations are often ob- served in space

Lin, Zhihong

358

Numerical studies of powerful terahertz pulse generation from a super-radiant surface wave oscillator  

SciTech Connect

The results of theoretical and numerical studies of coherent stimulated terahertz radiation from intense, subnanosecond electron beam are presented. The mechanism of terahertz pulse generation is associated with self-bunching of the beam and slippage of the wave over the whole electron flow. This so called Cherenkov super-radiance (SR) is used to propose a compact terahertz generator with high peak power. A large cross-section (overmoded), slow wave structure is designed to support the high power handling capability, and the mode competition is avoided by operating the device in the surface wave status. With 2.5 D particle-in-cell simulation, the 'hot' characteristics of the proposed super-radiant terahertz generator are investigated, and the numerical results show that the SR peak power could be further increased by optimizing the amplitude profile of electron pulse. Under the condition of 0.5 ns pulsewidth, 500 kV voltage, and 1.5 kA current, the 110 ps, 680 MW, and 0.14 THz SR pulse is achieved with a power efficiency of 90.67% in TM{sub 01} mode.

Zhang Hai [Key Laboratory of Physical Electronics and Devices of the Ministry of Education, Xi'an Jiaotong University, Xi'an, Shaanxi 710049 (China); Wang Jianguo [Key Laboratory of Physical Electronics and Devices of the Ministry of Education, Xi'an Jiaotong University, Xi'an, Shaanxi 710049 (China); Northwest Institute of Nuclear Technology, P.O. Box 69-12, Xi'an, Shaanxi 710024 (China); Tong Changjiang; Li Xiaoze [Northwest Institute of Nuclear Technology, P.O. Box 69-12, Xi'an, Shaanxi 710024 (China); Wang Guangqiang [Department of Engineering Physics, Tsinghua University, Beijing 100084 (China)

2009-12-15

359

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

360

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

361

Liquid wall inertial fusion energy power plants  

Microsoft Academic Search

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

Ralph W. Moir

1996-01-01

362

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

Microsoft Academic Search

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

Nikolaos A. Bakas; Brian F. Farrell

2008-01-01

363

Gravitational wave energy spectrum of a parabolic encounter  

NASA Astrophysics Data System (ADS)

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 (˜10%) provided that the azimuthal and radial orbital frequencies do not differ by more than ˜10%. For equatorial orbits in the Kerr spacetime, this corresponds to periapse radii of rp?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.

2010-11-01

364

Energy and directional signatures for plane quantized gravity waves  

E-print Network

Solutions are constructed to the quantum constraints for planar gravity (fields dependent on z and t only) in the Ashtekar complex connection formalism. A number of operators are constructed and applied to the solutions. These include the familiar ADM energy and area operators, as well as new operators sensitive to directionality (z+ct vs. z-ct dependence). The directionality operators are quantum analogs of the classical constraints proposed for unidirectional plane waves by Bondi, Pirani, and Robinson (BPR). It is argued that the quantum BPR constraints will predict unidirectionality reliably only for solutions which are semiclassical in a certain sense. The ADM energy and area operators are likely to have imaginary eigenvalues, unless one either shifts to a real connection, or allows the connection to occur other than in a holonomy. In classical theory, the area can evolve to zero. A quantum mechanical mechanism is proposed which would prevent this collapse.

Donald E. Neville

1997-04-01

365

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

366

Room temperature continuous wave THz quantum cascade laser source with high power operation  

NASA Astrophysics Data System (ADS)

We demonstrate the first room temperature continuous wave THz sources based on intracavity difference frequency generation from mid-infrared quantum cascade lasers. This accomplishment was enabled by integration of several key technologies, resulting in a new high efficiency waveguide design and improved thermal dissipation. Room temperature single mode emissions at 3.6 THz with an emitting power of 3 ?W and a mid-IR-to-THz conversion efficiency of 0.44 mW/W2 are obtained in continuous wave mode. THz peak power up to 1.4 mW in pulsed mode operation with a mid-IRto- THz conversion efficiency of 0.8 mW/W2 at 3.5 THz is also demonstrated.

Razeghi, M.; Lu, Q. Y.; Bandyopadhyay, N.; Slivken, S.; Bai, Y.

2014-09-01

367

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

368

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

NASA Astrophysics Data System (ADS)

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 ?s after the onset of the HiPIMS pulse. Further, a high concentration of double charged Ti++ 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; Herrendorf, Ann-Pierra; Drache, Steffen; Cada, Martin; Hubicka, Zdenek; Bogdanowicz, Robert; Tichy, Milan; Hippler, Rainer

2012-11-01

369

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

NASA Astrophysics Data System (ADS)

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

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

2013-09-01

370

Energy balance, wave shoaling and group celerity in Boussinesq-type wave propagation models  

NASA Astrophysics Data System (ADS)

This work focuses on the analysis of the linear shoaling performance of low order Boussinesq-type equations. Departing from the equation of the energy balance, a new velocity, vg, is obtained so that A?2vg is constant in space, being A? the wave height amplitude. The results are valid for a wide variety of low order Boussinesq-type equations. The new obtained velocity vg, which is in general different to the group celerity cg???/?k, allows a simple and analytical evaluation of the errors in linear shoaling, avoiding the numerical integration of the errors in the linear shoaling gradient. The general results are particularized for well known sets of Boussinesq-type equations.

Simarro, Gonzalo

2013-12-01

371

High power, continuous wave, singly resonant OPO based on MgO:PPLN  

Microsoft Academic Search

A continuous wave (CW), extra-cavity singly resonant optical parametric oscillator (SRO) has been demonstrated. The SRO was based on 5% Magnesium-Oxide doped periodically-poled Lithium Nio-bate (MgO:PPLN) pumped by a Yb fiber laser centered at 1064.7 nm. The SRO was able to generate light with idler wavelengths ranging from 2.9 to 4.1 mum. For a pump power of 15 W, the

J. Q. Zhao; B. Q. Yao; Y. Tian; Y. L. Ju; Y. Z. Wang

2010-01-01

372

High-power continuous wave 690 nm AlGaInP laser-diode arrays  

Microsoft Academic Search

High-power diode laser arrays emitting at 690 nm have been developed for solid-state laser pumping. The laser diode bars (fill factor [approx]0.7) have been fabricated from single quantum well AlGaInP-based heterostructures. Using silicon microchannel heatsinks, a record high 360 W\\/cm[sup 2] per emitting aperture is achieved under continuous wave operation.

J. A. Skidmore; M. A. Emanuel; R. J. Beach; W. J. Benett; B. L. Freitas; N. W. Carlson; R. W. Solarz

1995-01-01

373

NIST Measurement Services: cw Laser Power and Energy  

E-print Network

NIST Measurement Services: cw Laser Power and Energy Calibrations at NIST NIST Special Publication Measurement Services: cw Laser Power and Energy Calibrations at NIST Joshua Hadler Christopher L. Cromer John

374

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

E-print Network

, that is the energy that can be produced by sea waves. There are some critical advantages in this alternative form 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

375

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

376

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 9 July 2008; published 30 September 2008. [1] The distribution of wind-induced internal wave energy-scaled kinetic energy are all consistent with the available observations in the regions of significant wind

Miami, University of

377

Powerful short-pulse lasers pumped by the light of a shock wave front  

NASA Astrophysics Data System (ADS)

Radiation of a shock wave front proved to be very powerful light source for pumping of high power lasers. Particularly, explosively pumped iodine photodissociation lasers (EPIL) are nowadays well developed type of device of multikilojoule level, rather convenient for many applications. Usually such lasers work in free running mode and generate pulses of microsecond duration. Generating short pulses of nanosecond range require employing amplification scheme where amplifiers must work in waiting mode. It implies substantially other composition of active medium and entails rather important consequences for kinetics of the processes which follow photodissociation. Present report considers these problems as well as some experimental results obtained with short pulse EPIL.

Kirillov, Gennadi A.; Eroshenko, V. A.; Kochemasov, Gennady G.; Kulikov, Stanislav M.; Pevny, S. N.; Sukharev, Stanislav A.

2000-04-01

378

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

379

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

NASA Astrophysics Data System (ADS)

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

Saprykina, Yana; Divinskii, Boris

2013-04-01

380

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

381

Dust-acoustic waves and stability in the permeating dusty plasma. II. Power-law distributions  

SciTech Connect

The dust-acoustic waves and the stability theory for the permeating dusty plasma with power-law distributions are studied by using nonextensive q-statistics. In two limiting physical cases, when the thermal velocity of the flowing dusty plasma is much larger than, and much smaller than the phase velocity of the waves, we derived the dust-acoustic wave frequency, the instability growth rate, and the instability critical flowing velocity. As compared with the formulae obtained in part I [Gong et al., Phys. Plasmas 19, 043704 (2012)], all formulae of the present cases and the resulting plasma characteristics are q-dependent, and the power-law distribution of each plasma component of the permeating dusty plasma has a different q-parameter and thus has a different nonextensive effect. Further, we make numerical analyses of an example that a cometary plasma tail is passing through the interplanetary space dusty plasma and we show that these power-law distributions have significant effects on the plasma characteristics of this kind of plasma environment.

Gong Jingyu; Du Jiulin [Department of Physics, School of Science, Tianjin University, Tianjin 300072 (China); Liu Zhipeng [Department of Physics, School of Science, Tianjin University, Tianjin 300072 (China); Department of Fundamental Subject, Tianjin Institute of Urban Construction, Tianjin 300384 (China)

2012-08-15

382

Electromagnetic Surface Wave Propagation Applicable to UltraHigh Energy Neutrino  

E-print Network

Electromagnetic Surface Wave Propagation Applicable to UltraHigh Energy Neutrino Detection Peter of electromagnetic surface waves and their propagation is presented. The charged particle shower is modelled to simplify the problem by means of Fourier analysis and "conventional" antenna theory. Keywords: Surface wave

383

Applications of energy theorems to surface waves in a plasma P. Leprince and J. Marec  

E-print Network

1421 Applications of energy theorems to surface waves in a plasma P. Leprince and J. Marec results are applied to the axisymmetrical mode (surface wave) which is propagated along a plasma column m = 0 (surface wave). 2. Fundamental relations. - 2.1 SIMPLIFIED MODEL OF THE PROPAGATION STRUCTURE

Paris-Sud XI, Université de

384

Characteristics and energy balance of a plasma column sustained by a surface wave  

E-print Network

L-71 Characteristics and energy balance of a plasma column sustained by a surface wave M. Chaker, P expérimentale. Abstract. 2014 In this paper, we consider the case of a travelling surface wave sustaining,] Classification Physics Abstracts 52.40D - 52.80 1. Introduction. - The propagation of electron surface waves can

Paris-Sud XI, Université de

385

Argon surface wave discharges at medium pressure. Experiments and discussion on the energy balance  

E-print Network

999 Argon surface wave discharges at medium pressure. Experiments and discussion on the energy recombinaison dissociative de Ai+2 au-dessus de 100 Torr. Abstract. 2014 Argon surface wave discharges, created. Generation and maintaining of long plasma columns by surface waves, from very low pressure (~100 mTorr) up

Paris-Sud XI, Université de

386

Energy conserving local discontinuous Galerkin methods for wave propagation Yulong Xing1  

E-print Network

and analyze a local discontinuous Galerkin (LDG) method for solving the wave equation. We prove optimal error propagation, the constant coefficient wave equation is the simplest one and has been extensively studied. OneEnergy conserving local discontinuous Galerkin methods for wave propagation problems Yulong Xing1

Shu, Chi-Wang

387

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

E-print Network

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

388

Power quality and reliability supply improvement 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; C. Rossi

2004-01-01

389

Power Conversion and Energy Storage System for a Fusion Reactor 2.Electric Power Flow in a Nuclear Fusion Power Plant  

Microsoft Academic Search

The ultimate purpose of fusion energy development is to utilize the produced fusion power mainly as electric power for ease of transmission and conversion. Irrespective of the type of fusion power plant, large circulating electric power should exist in the plant for the purpose of plasma heating, current drive, and soon. This chapter describes the typical electric power flow in

Makoto Matsukawa; Kenji Tobita; Hirotaka Chikaraishi; Akio Sagara; Takayoshi Norimatsu

2004-01-01

390

Pulse power systems using inductive energy storage  

SciTech Connect

For the last 10-15 years Efremov Institute has been involved in research and development activities in the field of pulse power inductive storages (IS). The wide range of problems associated with IS-systems (Inductor Storage System) has been investigated: storage system, magnets energy transfer network, etc. Different charging sources have been designed using synchronous generators, high-power thyristor converters, homopolar generators. Magnet systems were optimized for different requirements. As a result of these studies inductive storages up to 9 {center dot} 10{sup 8} J have been designed and constructed. Different options of energy transfer networks are investigated and realized. The wide range of single-shot and multi-shot switches (breakers and closers) with peak currents up to 300 kA and voltage up to 40 kV have been tested, some of them are working on different installations. In this paper three types of pulse power systems using IS and their main performances are given. Besides the design features of different switches are described.

Druzhinin, A.S.; Kuchinsky, V.G.; Larionov, B.A.; Roshal, A.G.; Silin, V.P.; Soikin, V.F. (D.V. Efremov Scientific Research Inst. of Electrophysical Apparatus, Leningrad (SU))

1992-01-01

391

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 are discarded in landfills. The Camargo Waste to Energy (WTE) power station is an opportunity to continue

Zhou, Yaoqi

392

Electrical Power Production Facilities from Green Energy Sources  

Microsoft Academic Search

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

Ayhan Demirbas

2006-01-01

393

Measuring Power and Energy of CMOS Circuits: A Comparative Analysis  

E-print Network

DD(t), it is possible to calculate the charge, energy and power consumed by an IC. The main problem lays on the properMeasuring Power and Energy of CMOS Circuits: A Comparative Analysis J. Rius, A. Peidro, S. Manich presents and compares a set of experimental results on the measurement of power and energy consumed using

Boemo, Eduardo

394

Power and Energy Management for Server Systems Ricardo Bianchini  

E-print Network

, of servers and supporting cooling infrastructures. Research on power and energy management for servers canPower and Energy Management for Server Systems Ricardo Bianchini and Ram Rajamony Department, NJ Austin, TX ricardob@cs.rutgers.edu rajamony@us.ibm.com Abstract Power and energy consumption

Bianchini, Ricardo

395

Determination of an optimum frequency of square wave power for fouling mitigation in desalting electrodialysis in the presence of humate  

Microsoft Academic Search

Membrane fouling in electrodialysis (ED) can be minimized by using optimized pulsed power instead of direct current (DC) power. For the determination of an optimum frequency, effects of the square wave power with various frequencies on fouling mitigation were studied in the presence of humate as a foulant in a NaCl solution. In desalting of a NaCl solution with humate

Jin-Soo Park; Hong-Joo Lee; Seung-Hyeon Moon

2003-01-01

396

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

SciTech Connect

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

Markov, G. A.; Belov, A. S.; Komrakov, G. P. [Lobachevsky State University (Russian Federation); Parrot, M. [Environmental Physics and Chemistry Laboratory (France)

2012-03-15

397

Three-dimensional sound signals and their relevance to wave energy quantities and sound interference products  

Microsoft Academic Search

Signals are graphic representations of vibrations\\/waves and, like every representation, capture only selected attributes of the phenomenon they are meant to represent. The often assumed equivalence between signals and sound waves obscures the fact that two-dimensional signals are not fit to (a) represent wave-energy quantities consistently across frequencies, (b) account for the alternating positive\\/negative amplitude values of modulated waves with

Pantelis Vassilakis

2003-01-01

398

Solar power satellite—Life-cycle energy recovery considerations  

Microsoft Academic Search

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

J. Blumenberg

1995-01-01

399

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

E-print Network

Cormick (1980)). To achieve power output comparable to a conventional power plant or a wind-turbine farm the extraction efficiency significantly. For comparison an alternate theory for the efficiency away from the band to energy absorbers. without giving numerical results. These methods can in principle deal with several

Boyer, Edmond

400

Waves  

E-print Network

WAVES BY Mari LaCure Submitted to the graduate degree program in Visual Art and the Graduate Faculty of the University of Kansas in partial fulfillment of the requirements for the degree of Master’s of Fine Arts. Yoonmi Nam Chairperson... Committee members: Shawn Bitters Michael Krueger Date Defended: March 10, 2010 2 The Thesis Committee for Mari LaCure certifies that this is the approved Version of the following thesis: WAVES...

LaCure, Mari Mae

2010-04-29

401

Spatial structure of auroral day-time ionospheric electron density irregularities generated by a powerful HF-wave  

Microsoft Academic Search

We describe an experiment in satellite radio- wave probing of the ionosphere, modified by powerful waves from the HF heating facility at Tromsø (Norway) in May 1995. Amplitude scintillations and variations of the phase of VHF signals from Russian navigational satellites passing over the heated region were observed. We show that both large-scale electron density irregu- larities (several tens of

E. D. Tereshchenko; B. Z. Khudukon; M. T. Rietveld; A. Brekke

1998-01-01

402

Spatial structure of auroral day-time ionospheric electron density irregularities generated by a powerful HF-wave  

Microsoft Academic Search

We describe an experiment in satellite radio-wave probing of the ionosphere, modified by powerful waves from the HF heating facility at Tromsø (Norway) in May 1995. Amplitude scintillations and variations of the phase of VHF signals from Russian navigational satellites passing over the heated region were observed. We show that both large-scale electron density irregularities (several tens of kilometers in

E. D. Tereshchenko; B. Z. Khudukon; M. T. Rietveld; A. Brekke

1998-01-01

403

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

Federal Register 2010, 2011, 2012, 2013

...Energy Conservation Standards for Certain External Power Supplies; Correction AGENCY...energy conservation standards for certain external power supplies to re-insert a table...conservation standards for all Class A external power supplies to meet. DATES:...

2012-04-16

404

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

PubMed

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

Langhamer, Olivia; Wilhelmsson, Dan

2009-10-01

405

Photovoltaic power - An important new energy option  

NASA Technical Reports Server (NTRS)

A review of photovoltaic (PV) power technology is presented with an emphasis of PV as an economical and technically feasible alternative source of energy. The successful completion of the development and transfer of emerging low-cost technologies into a fully commercialized status are identified as the means to the realization of this option's full potential. The DOE National Photovoltaics Program, a significant sponsor of PV R&D, expects both flat-plate and concentrator collectors to meet established cost targets. Citing the DOE large flat-plate grid-connected system project of the Sacramento Municipal Utility District, current technology modules priced at near $5/Wp (1983 dollars) are steadily reducing costs. A recent DOE study suggests that PV-generated electricity produced at a 30-year levelized cost of 15 cents per kWh would represent a viable energy supply alternative for the nation.

Ferber, R. R.

1983-01-01

406

Gravitational wave sirens as a triple probe of dark energy  

SciTech Connect

Gravitational wave standard sirens have been considered as precision distance indicators of high redshift; however, at high redshift standard sirens or standard candles such as supernovae suffer from lensing noise. We investigate lensing noise as a signal instead and show how measurements of the maximum demagnification (minimum convergence) probe cosmology in a manner highly complementary to the distance itself. Revisiting the original form for minimum convergence we quantify the bias arising from the commonly used approximation. Furthermore, after presenting a new lensing probability function we discuss how the width of the lensed standard siren amplitude distribution also probes growth of structure. Thus standard sirens and candles can serve as triple probes of dark energy, measuring both the cosmic expansion history and growth history.

Linder, Eric V, E-mail: evlinder@lbl.gov [Berkeley Laboratory, University of California, Berkeley, CA 94720 (United States)

2008-03-15

407

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

NASA Astrophysics Data System (ADS)

We use the latest cosmic microwave background (CMB) observations to provide updated constraints on the dark matter lifetime as well as on p-wave suppressed annihilation cross sections in the 1 MeV to 1 TeV mass range. In contrast to scenarios with an s-wave dominated annihilation cross section, which mainly affect the CMB close to the last scattering surface, signatures associated with these scenarios essentially appear at low redshifts (zlesssim50) when structure began to form, and thus manifest at lower multipoles in the CMB power spectrum. We use data from Planck, WMAP9, SPT and ACT, as well as Lyman-? measurements of the matter temperature at z ~ 4 to set a 95% confidence level lower bound on the dark matter lifetime of ~ 4 × 1025 s for m? = 100 MeV. This bound becomes lower by an order of magnitude at m? = 1 TeV due to inefficient energy deposition into the intergalactic medium. We also show that structure formation can enhance the effect of p-wave suppressed annihilation cross sections by many orders of magnitude with respect to the background cosmological rate, although even with this enhancement, CMB constraints are not yet strong enough to reach the thermal relic value of the cross section.

Diamanti, Roberta; Lopez-Honorez, Laura; Mena, Olga; Palomares-Ruiz, Sergio; Vincent, Aaron C.

2014-02-01

408

Electric power processing, distribution, management and energy storage  

NASA Technical Reports Server (NTRS)

Power distribution subsystems are required for three elements of the SPS program: (1) orbiting satellite, (2) ground rectenna, and (3) Electric Orbiting Transfer Vehicle (EOTV). Power distribution subsystems receive electrical power from the energy conversion subsystem and provide the power busses rotary power transfer devices, switchgear, power processing, energy storage, and power management required to deliver control, high voltage plasma interactions, electric thruster interactions, and spacecraft charging of the SPS and the EOTV are also included as part of the power distribution subsystem design.

Giudici, R. J.

1980-01-01

409

Wind Power Today: 2000 Wind Energy Program Highlights  

Microsoft Academic Search

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

Weis-Taylor

2001-01-01

410

Wind power today: 1999 Wind Energy program highlights  

Microsoft Academic Search

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

Weis-Taylor

2000-01-01

411

Geothermal Energy--Clean Power From the Earth's Heat  

E-print Network

in providing alternative sources of energy. Alternative technologies that employ the Sun's energy (solar Geothermal Energy--Clean Power From the Earth's Heat Circular 1249 U.S. Department of the Interior U.S. Geological Survey #12;Geothermal Energy--Clean Power From the Earth's Heat By Wendell A

412

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

SciTech Connect

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

Horisawa, Hideyuki; Sumida, Sota [Department of Aeronautics and Astronautics, Tokai University, 1117 Kitakaname, Hiratsuka, Kanagawa 259-1292 Japan (Japan); Funaki, Ikkoh [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, Sagamihara, Kanagawa Japan (Japan)

2010-05-06

413

High power subterahertz electromagnetic wave radiation from GaN photoconductive switch  

Microsoft Academic Search

The authors present apparently the observation of subterahertz electromagnetic wave emission from GaN based large aperture photoconductive switches (LA-PCSWs) excited by ultraviolet femtosecond laser pulses. The photoconductive layer of the GaN LA-PCSW is doped with carbon giving rise to a resistivity as high as 60 MOmega cm. The absolute energy of the emitted radiation pulses is measured to be 93.3

Osamu Imafuji; Brahm Pal Singh; Yutaka Hirose; Yasuyuki Fukushima; Shinichi Takigawa

2007-01-01

414

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

E-print Network

In a fusion reactor burning deuterium and tritium (D-T), the reaction is sustained by a-particle heating in one of two ways: one; it could act as a catalyst, with growth due to the cr-pa&es offset entirely and to be sustainable. First, almost the full energy of the alpha,particle ought to be extracted as the wave diffuses

415

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

DOEpatents

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

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

2011-12-06

416

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

NASA Technical Reports Server (NTRS)

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

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

1991-01-01

417

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

Microsoft Academic Search

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

Junseok Song; Ruichen Zhao; Alexis Kwasinski

2011-01-01

418

Energy growth for a nonlinear oscillator coupled to a monochromatic wave  

NASA Astrophysics Data System (ADS)

A system consisting of a chaotic (billiard-like) oscillator coupled to a linear wave equation in the three-dimensional space is considered. It is shown that the chaotic behavior of the oscillator can cause the transfer of energy from a monochromatic wave to the oscillator, whose energy can grow without bound.

Turaev, Dmitry V.; Warner, Christopher; Zelik, Sergey

2014-07-01

419

Optimal energy conserving local discontinuous Galerkin methods for second-order wave equation in heterogeneous media  

E-print Network

propagation, local discontinuous Galerkin method, energy conserva- tion, optimal error estimate, heterogeneousOptimal energy conserving local discontinuous Galerkin methods for second-order wave equation in heterogeneous media Ching-Shan Chou1 , Chi-Wang Shu2 and Yulong Xing3 Abstract Solving wave propagation problems

Shu, Chi-Wang

420

Protonic conduction wave energy converter. Final report, January 1December 31, 1978  

Microsoft Academic Search

An initial study of the feasibility of using electrochemical hydrogen concentration cells with protonic conductors for the conversion of ocean wave energy into electricity has been carried out. The system considered uses the potential energy of waves or ocean swells to alternately compress and expand hydrogen gas which thereby drives a concentration cell. A theoretical analysis of four idealized embodiments

1979-01-01

421

Protonic conduction wave energy converter. Final report, January 1, 1978December 31, 1978  

Microsoft Academic Search

An initial study of the feasibility of using electrochemical hydrogen concentration cells with protonic conductors for the conversion of ocean wave energy into electricity has been carried out. The system considered uses the potential energy of waves or ocean swells to alternately compress and expand hydrogen gas which thereby drives a concentration cell. A theoretical analysis of four idealized embodiments

1979-01-01

422

Aero-Acoustic Analysis of Wells Turbine for Ocean Wave Energy Conversion  

E-print Network

Aero-Acoustic Analysis of Wells Turbine for Ocean Wave Energy Conversion Ralf Starzmann Fluid of harnessing the energy from ocean waves is the oscillating water column (OWC) device. The OWC converts of the acoustic emission associated with its operation. A systematic analysis of the effects of rotor hub to tip

Frandsen, Jannette B.

423

The synoptic setting and possible energy sources for mesoscale wave disturbances  

NASA Technical Reports Server (NTRS)

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

Uccellini, Louis W.; Koch, Steven E.

1987-01-01

424

This paper presents an investigation of power and energy transduction in piezoelectric wafer active sensors (PWAS) on isotropic structure for structural health  

E-print Network

is sensed by active interrogation of the structure with elastic waves. The power and energy flow in active1 ABSTRACT This paper presents an investigation of power and energy transduction in piezoelectric wafer active sensors (PWAS) on isotropic structure for structural health monitoring (SHM). After

Giurgiutiu, Victor

425

Quantified Energy Dissipation Rates: Electromagnetic Wave Observations in the Terrestrial Bow Shock  

E-print Network

We present the first quantified measure of the rate of energy dissipated per unit volume by high frequency electromagnetic waves in the transition region of the Earth's collisionless bow shock using data from the THEMIS spacecraft. Every THEMIS shock crossing examined with available wave burst data showed both low frequency ( 10 Hz) electromagnetic and electrostatic waves throughout the entire transition region and into the magnetosheath. The waves in both frequency ranges had large amplitudes, but the higher frequency waves, which are the focus of this study, showed larger contributions to both the Poynting flux and the energy dissipation rates. The higher frequency waves were identified as combinations of ion-acoustic waves, electron cyclotron drift instability driven waves, electrostatic solitary waves, and whistler mode waves. These waves were found to have: (1) amplitudes capable of exceeding dB ~ 10 nT and dE ~ 300 mV/m, though more typical values were dB ~ 0.1-1.0 nT and dE ~ 10-50 mV/m; (2) energy flu...

Wilson, L B; Breneman, A W; Contel, O Le; Cully, C; Turner, D L; Angelopoulos, V

2013-01-01

426

A self-powered mechanical strain energy sensor  

Microsoft Academic Search

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

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

2001-01-01

427

Contribution to the Chapter on Wind Power Energy Technology  

E-print Network

Contribution to the Chapter on Wind Power Energy Technology Perspectives 2008 Jørgen Lemming; Poul in the wind energy sector. As a result, better electrical grids suited for wind power are being developed&D areas to foster continued growth in wind power are to increase the value and reduce uncertainties

428

Renewable energy credit driven wind power growth for system reliability  

Microsoft Academic Search

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

Rajesh Karki

2007-01-01

429

High power, continuous wave, singly resonant OPO based on MgO:PPLN  

Microsoft Academic Search

A continuous wave (CW), extra-cavity singly resonant optical parametric oscillator (SRO) has been demonstrated. The SRO was\\u000a based on 5% Magnesium-Oxide doped periodically-poled Lithium Nio-bate (MgO:PPLN) pumped by a Yb fiber laser centered at 1064.7\\u000a nm. The SRO was able to generate light with idler wavelengths ranging from 2.9 to 4.1 ?m. For a pump power of 15 W, the

J. Q. Zhao; B. Q. Yao; Y. Tian; Y. L. Ju; Y. Z. Wang

2010-01-01

430

Observation of high-power millimeter wave emission from a virtual cathode  

SciTech Connect

Intense bursts of mm wave power have been observed in microwave generation experiments with a relativistic electron beam (REB) virtual cathode oscillator. In this device an electron beam is injected into a drift space at a current above the space-charge-limit, and a potential develops downstream which is large enough to reflect electrons back to the source region. Two mechanisms can give rise to microwave oscillations in a virtual cathode device: electrons reflexing between the real and virtual cathodes, and oscillations in the amplitude and position of the virtual cathode. Typically both mechanisms are present, but in the present experiments reflexing has been shown to be dominant.

Davis, H.A.; Bartsch, R.R.; Sherwood, E.G.; Stringfield, R.M.; Thode, L.E.

1985-01-01

431

Saturation wind power potential and its implications for wind energy  

E-print Network

Saturation wind power potential and its implications for wind energy Mark Z. Jacobsona,1 to determine the maximum theo- retical wind power potential on Earth, based on the concept of "saturation". The saturation wind power potential (SWPP) is the maximum wind power that can be extracted upon increasing

432

Attenuation of seismic shear wave energy in Switzerland  

NASA Astrophysics Data System (ADS)

Modelling the attenuation of shear wave energy is an important component of seismic hazard analysis. Previous studies have shown how attenuation, particularly in the uppermost layers of the crust, is regionally dependent. The impact of this is that the decay of energy radiating from an earthquake will vary from place to place. To quantify the regional attenuation in Switzerland we model the Fourier spectral amplitude of small-to-moderate earthquakes, recorded on the local seismic networks. High-frequency decay is parametrized by Q and ?, while apparent geometrical spreading models account for the frequency-independent decay of energy. We analyse ground motion encompassing the significant duration of shaking to provide models that are useful for the purpose of seismic hazard analysis. Two methods are used to estimate the whole path attenuation parameter, t*: first, a simultaneous fit of the source model and attenuation effects across the entire spectral bandwidth for earthquakes with M > 2; and secondly, a linear fit of an attenuation model to the high-frequency part of the spectrum for earthquakes with M > 3.5. The t* parameter is found to vary with hypocentral distance consistent with a weakly attenuating crust and strongly attenuating uppermost layer. 1-D tomographic inversions indicate a profile of increasing Q with depth down to the Moho. Frequency-independent decay is parametrized using a three-part model which allows for the inclusion of Moho reflection phases in the spectrum in the range of 20-140 km in the Swiss Foreland and from 70 to 140 km in the Swiss Alps.

Edwards, Benjamin; Fäh, Donat; Giardini, Domenico

2011-05-01

433

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

434

In-tank tests of a dielectric elastomer generator for wave energy harvesting  

NASA Astrophysics Data System (ADS)

Wave energy harvesting is one of the most promising applications for Dielectric Elastomer Generators. A simple and interesting concept of a Wave Energy Converter based on Dielectric Elastomers is the Polymeric Oscillating Water Column (Poly-OWC). In this paper, preliminary experimental results on the assessment of a small-scale Poly-OWC prototype are presented. The scale of the considered prototype is 1:50. Tests are conducted in a wave-flume by considering sea state conditions with different wave amplitudes and frequencies. The obtained experimental results confirm the viability of the Poly-OWC device.

Vertechy, R.; Fontana, M.; Rosati Papini, G. P.; Forehand, D.

2014-03-01

435

Maximum wind energy extraction strategies using power electronic converters  

Microsoft Academic Search

This thesis focuses on maximum wind energy extraction strategies for achieving the highest energy output of variable speed wind turbine power generation systems. Power electronic converters and controls provide the basic platform to accomplish the research of this thesis in both hardware and software aspects. In order to send wind energy to a utility grid, a variable speed wind turbine

Quincy Qing Wang

2003-01-01

436

Economic efficiency of power stations using renewable energy sources  

SciTech Connect

This article examines the viability of power stations using the renewable resources of wind energy, tidal energy, and geothermal energy. General pros and cons of renewable resources are discussed, and the socioeconomic impacts and environmental impacts of these resources are listed and compared to those of traditional thermal and hydroelectric power plants.

Voronkin, A.F.; Lisochkina, T.V.; Malinina, T.V. [and others

1995-12-01

437

How Speculation Can Save Power and Energy Matthew Frank  

E-print Network

that can reduce both power and energy consumption for bandwidth limited applications. 1 Introduction, for bandwidth constrained applications, parallelism combined with voltage scaling can reduce energy consumption-delay for reduced power and energy. First let's generalize our calculation of ¡ . Suppose that we have a correct

Frank, Matthew I.

438

Optimal Power Cost Management Using Stored Energy in Data Centers  

E-print Network

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

Urgaonkar, Bhuvan

439

High-power, broadband, continuous-wave, mid-infrared optical parametric oscillator based on MgO:PPLN  

Microsoft Academic Search

We present a broadband, high-power, fiber-laser-pumped, continuous-wave optical parametric oscillator for mid-infrared by exploiting extended phase-matching properties of MgO:PPLN. Total powers of 11.3W, with 5.3W broadband mid-infrared idler in excellent beam quality are generated.

S. Chaitanya Kumar; Ritwick Das; G. K. Samanta; M. Ebrahim-Zadeh

2010-01-01

440

An advanced electronic power conditioner for 12 GHZ, 100 W to 150 W travelling wave tube amplifiers  

Microsoft Academic Search

For the first Direct Broadcasting Satellites (DBS), Travelling Wave Tube Amplifiers (TWTA's) with 200 W to 260 W output power were required due to the low capability of the receiving equipment. However, as a result of great improvements in receiving equipment the output power of the TWTA's can be reduced to between 100 W and 150 W for future DBS

Karl-Heinz Huebner

1988-01-01

441

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

442

Surface current effects on the fetch-limited growth of wave energy  

NASA Astrophysics Data System (ADS)

To study the fetch-limited growth of wind wave energy over a region with significant lateral shear of the current field, this study exploited data obtained from two linear phased-array High Frequency (HF) radar systems. Both the near-surface currents and wave energy and period were mapped over the highly sheared inshore boundary of the Florida Current. The wave energy growth during two periods when the winds were steady for >12 hours and were directed offshore was computed over a range of fetches from 5 to 45 km. The observed energy growth rates were significantly (˜50 %) lower than predicted by the Donelan et al. (1992) empirical formulation over the high vorticity region. The reduced growth rate was consistent with a shift of the wind stress direction into the current direction due to refraction of the wave field. Dimensionless wave energy increased by as much as 100% over neighboring values when the vertical component of the surface current vorticity was a global minimum. While trapping and enhancement of wave energy is predicted by wave ray theory, it has never before been confirmed within the Florida Current with coincident wave and current measurements.

Haus, Brian K.

2007-03-01

443

High power, continuous wave, singly resonant OPO based on MgO:PPLN  

NASA Astrophysics Data System (ADS)

A continuous wave (CW), extra-cavity singly resonant optical parametric oscillator (SRO) has been demonstrated. The SRO was based on 5% Magnesium-Oxide doped periodically-poled Lithium Nio-bate (MgO:PPLN) pumped by a Yb fiber laser centered at 1064.7 nm. The SRO was able to generate light with idler wavelengths ranging from 2.9 to 4.1 ?m. For a pump power of 15 W, the idler output power varied from 7.54 W at 3.03 ?m to 1.04 W at 4.05 ?m. The oscillation thresholds were 2.0 W at idler wavelength 3.03 ?m and 7.0 W at 4.05 ?m.

Zhao, J. Q.; Yao, B. Q.; Tian, Y.; Ju, Y. L.; Wang, Y. Z.

2010-10-01

444

On the Generation of Flux-Tube Waves in Stellar Convection Zones. III. Longitudinal Tube Wave-Energy Spectra and Fluxes for Late-Type Stars  

Microsoft Academic Search

The wave-energy spectra and fluxes for longitudinal tube waves generated in stellar convection zones are computed by using analytical methods developed in the two previous papers of this series. The main physical process responsible for the generation of these waves is the interaction between a thin and vertically oriented magnetic flux tube and the external turbulent convection. The spatial component

Z. E. Musielak; R. Rosner; P. Ulmschneider

2000-01-01

445

The slow-mode nature of compressible wave power in solar wind turbulence  

E-print Network

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

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

2011-01-01

446

High-Harmonic Fast-Wave Power Flow Along Magnetic Field Lines in the Scrape-Off Layer of NSTX  

SciTech Connect

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

Perkins, R. J. [Princeton Plasma Physics Laboratory (PPPL); Hosea, J. [Princeton Plasma Physics Laboratory (PPPL); Kramer, G. [Princeton Plasma Physics Laboratory (PPPL); Ahn, Joonwook [ORNL; Bell, R. E. [Princeton Plasma Physics Laboratory (PPPL); Diallo, A. [Princeton Plasma Physics Laboratory (PPPL); Gerhardt, S. [Princeton Plasma Physics Laboratory (PPPL); Gray, T. K. [Oak Ridge National Laboratory (ORNL); Green, David L [ORNL; Jaeger, Erwin Frederick [ORNL; Jaworski, M. A. [Princeton Plasma Physics Laboratory (PPPL); LeBlanc, B [Princeton Plasma Physics Laboratory (PPPL); McLean, Adam G [ORNL; Maingi, Rajesh [ORNL; Phillips, C. K. [Princeton Plasma Physics Laboratory (PPPL); Roquemore, L. [Princeton Plasma Physics Laboratory (PPPL); Ryan, Philip Michael [ORNL; Sabbagh, S. A. [Columbia University; Taylor, G. [Princeton Plasma Physics Laboratory (PPPL); Wilson, J. R. [Princeton Plasma Physics Laboratory (PPPL)

2012-01-01

447

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

E-print Network

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

Chiao, Jung-Chih

448

Simple power law for transport ratio with bimodal distributions of coarse sediments under waves  

NASA Astrophysics Data System (ADS)

Morphodynamic models of coastal evolution require relatively simple parameterizations of sediment transport for application over larger scales. Here we present a transport parameterization for bimodal distributions of coarse quartz grains using simulations from a discrete particle model for sheet flow and near sheet flow conditions. The discrete particle model simulates the simplest one-dimensional fluid using a turbulent eddy viscosity determined from a mixing length coupled to particle motions. The motions of individual sand grains are simulated using spherical elements. Newton's second law in translational and rotational forms is solved for every particle in the domain as determined by both grain-grain and grain-fluid interactions. The forcing from idealized monochromatic waves is accomplished by specifying a spatially constant, time varying horizontal pressure gradient acting on the simulation domain. Consequently, the time series of the free-stream fluid acceleration and velocity are also fixed. Simulations cover a range of wave forcing, diameter ratios for the large and small grains in the bimodal size distribution, and mass ratios of large to small grains in the simulation domain, for a total of 243 unique simulation conditions. The simulation results are successfully parameterized with a simple power law that allows for the prediction of the transport rates of each size fraction in the bimodal distribution. The simple power law determined from simulations provides favorable predictions of transport rates for each size fraction when applied to available laboratory data for sheet flow with bimodal size distributions. It is important to note that rapid vertical kinematic sorting of grains by size is explicitly simulated with the model and thus implicitly captured by the power law. Discussion focuses on practical application of the power law.

Calantoni, Joseph; Thaxton, Christopher S.

2008-03-01

449