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1

Conversion between Magnetic Energy and Mechanical Energy.  

National Technical Information Service (NTIS)

A method of converting magnetic energy to mechanical energy comprising subjecting a material of the formula R sub x T sub 1-x where in R is a rare earth or mixtures thereof, T is Fe, Ni, Co, Mn, or mixtures thereof, and 0 < x < 1, to a change in magnetic ...

A. E. Clark H. S. Belson

1981-01-01

2

High-Energy Electromagnetic Conversion Processes in Intense Magnetic Fields  

Microsoft Academic Search

General characteristics of magnetic bremsstrahlung (synchrotron radiation) are derived on the basis of calculations utilizing exact relativistic matrix elements. The spectral and total energy losses may be described by compact expressions incorporating radiative and quantum corrections. Comparisons of the relative efficacy of matter and magnetic fields as bremsstrahlung radiators indicate that even under relatively conservative conditions the natural conversion rates

Thomas Erber

1966-01-01

3

Magnetic Energy Conversion on the Sun.  

National Technical Information Service (NTIS)

For a 3D magnetic field such as exists above sunspots or magnetic fragments of complex polarity or in prominence fields, it is suggested that reconnection may be defined to occur when there is a singular line (a field line with neighboring X-type topology...

E. R. Priest

1989-01-01

4

A permanent magnet tubular linear generator for wave energy conversion  

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

5

Permanent magnet synchronous generators for regenerative energy conversion - a survey  

Microsoft Academic Search

A survey on recently installed or developed permanent magnet (PM) synchronous generators for energy conversion in regenerative and alternative power supply systems is given. Its focus is for low speed machines on geared and gearless PM generator systems for wind power plants and small PM hydro generators in gearless coupling. For distributed co-generation of heat and electrical power by micro

Andreas Binder; Tobias Schneider

2005-01-01

6

Direct fission fragment energy conversion utilizing magnetic collimation  

Microsoft Academic Search

The objective of this dissertation was to determine the technological feasibility of direct fission fragment energy conversion utilizing magnetic collimation (DFFEC-MC). This objective was accomplished by producing a conceptual design for a DFFEC-MC system and by analysis of the potential DFFEC-MC system performance. Consistent analysis and evaluation of the technological feasibility of the DFFEC-MC concept were achieved using state-of-the-art computer

Pavel Valeryevich Tsvetkov

2002-01-01

7

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

Microsoft Academic Search

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

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

2005-01-01

8

Direct energy conversion of exhaust fusion plasma by magnetic deflection  

Microsoft Academic Search

Energy extraction from the exhaust plasma of the divertor in the PRDM fusion reactor could be feasible by the action of magnetic separation and deflection. The exhaust chamber could be modified into a cylindrical form with the collecting electrodes lining its internal surface. Range of feasible deflecting radii, axial travel and angle of inclinations have been obtained for the impinging

K. Denno

1977-01-01

9

Three-phase Four-wire Autonomous Wind Energy Conversion System Using Permanent Magnet Synchronous Generator  

Microsoft Academic Search

This article deals with an autonomous wind energy conversion system employing a permanent magnet synchronous generator feeding three-phase four-wire local loads in stand-alone mode without using a mechanical position sensor. The proposed autonomous wind energy conversion system utilizes two back-to-back connected pulse width modulated insulated gate bipolar transistors based voltage source converters with a battery energy storage system at their

Puneet K. Goel; Bhim Singh; S. S. Murthy; Shailendra K. Tiwari

2010-01-01

10

Neural network controller for a permanent magnet generator applied in a wind energy conversion system  

Microsoft Academic Search

In this paper a neural network controller for achieving maximum power tracking as well as output voltage regulation, for a wind energy conversion system (WECS) employing a permanent magnet synchronous generator, is proposed. The permanent magnet generator (PMG) supplies a DC load via a bridge rectifier and two buck–boost converters. Adjusting the switching frequency of the first buck–boost converter achieves

Mona N. Eskander

2002-01-01

11

Rare earth permanent magnets and energy conversion processes  

Microsoft Academic Search

Traditionally in magnetoelectric devices the stator has been the massive and static part of the device and the dynamic element has been a moving coil. With improvements in the volumetric efficiency of permanent magnets it is possible to rearrange magnetic circuit elements and invert devices. Rare earth permanent magnets exhibit a high magnetic moment per unit volume and have extreme

R. J. Parker

1977-01-01

12

Reduced order observer for permanent magnet synchronous generator in wind energy conversion system  

Microsoft Academic Search

This paper presents an approach to develop a simple reduced speed observer for permanent magnet synchronous generator (PMSG) in wind energy conversion system (WECS). The speed and rotor position estimation of the PMSG are obtained by only measuring phase voltage and current. Maximum wind energy extraction is achieved by running the wind turbine generator in variable-speed mode. The rotor speed

Lotfi KRICHEN; Hsan HADJ ABDALLAH; Abderrazak OUALI

2007-01-01

13

Direct Conversion of the Energy of Laser and Fusion Plasma Clouds to Electrical Energy During Expansion in a Magnetic Field  

Microsoft Academic Search

The paper deals with the physical and electrotechnical principles of the promising method of direct conversion of the kinetic energy of an expanding plasma cloud to electrical energy by inductive generation of currents in short–circuited load coils that enclose the plasma and are oriented across the external magnetic field. An analysis of plasma deceleration by a magnetic field and transfer

Yu. P. Zakharov; A. V. Melekhov; V. G. Posukh; I. F. Shaikhislamov

2001-01-01

14

Energy Conversions  

NSDL National Science Digital Library

Students evaluate various everyday energy conversion devices and draw block flow diagrams to show the forms and states of energy into and out of the device. They also identify the forms of energy that are useful and the desired output of the device as well as the forms that are not useful for the intended use of the item. This can be used to lead into the law of conservation of energy and efficiency. The student activity is preceded by a demonstration of a more complicated system to convert chemical energy to heat energy to mechanical energy. Drawing the block energy conversion diagram for this system models the activity that the students then do themselves for other simpler systems.

Office Of Educational Partnerships

15

Loss and Rating Considerations of a Wind Energy Conversion System with Reactive Compensation by Magnetic Energy Recovery Switch (MERS)  

Microsoft Academic Search

Electrical conversion system for permanent magnet wind generators is challenging due to the large rating of power electronics devices needed and the associated costs. Additionally, due to the large inductance present in the generator (synchronous reactance), voltage drops results with resistive load and the generator output power is limited. A solution utilizing an active series compensation device called magnetic energy

JanArild Wiik; Arkadiusz Kulka; Takanori Isobe; Kazuhiro Usuki; M. Molinas; T. Takaku; T. Undeland; R. Shimada

2008-01-01

16

Direct energy conversion systems  

Microsoft Academic Search

The potential importance of direct energy conversion to the long-term development of fusion power is discussed with stress on the possibility of alleviating waste heat problems. Two approaches to direct conversion, i.e., direct collection and magnetic expansion are reviewed. Bibtex entry for this abstract Preferred format for this abstract (see Preferences) Find Similar Abstracts: Use: Authors Title Keywords (in text

G. H. Miley

1978-01-01

17

Energy conversion  

SciTech Connect

Energy conversion capable of receiving input energy in thermal or radiant form at a variable rate and releasing energy in thermal, radiant or electrical form independent of rate is accomplished by providing a buffer member of a material that has three criteria: a melting temperature above 1300/sup degree/ K, a thermal conductance greater than 0.1 in calories per square centimeter per centimeter per degree per second and a latent heat of fusion of the order of 1 kilocalorie per mole. The converter can absorb energy of multiple types, store it and then release it in a form compatible with the prospective use. Sunlight of daylight duration and varying intensity is converted to steady 24 hour a day electrical output.

Woodall, J.M.

1982-02-16

18

Modeling, simulation and control of grid connected Permanent Magnet Generator (PMG)-based small wind energy conversion system  

Microsoft Academic Search

A small scale wind energy conversion system has tremendous diversity of use and operating conditions, and consequently is evolving rapidly along with the large scale wind energy conversion system for generation of electricity in either stand-alone or grid connected applications. In recent years, the grid connected small wind turbine industry is primarily dominated by the Permanent Magnet Generator (PMG) machines.

M. Arifujjaman

2010-01-01

19

Vocational-Technical Physics Project. The Alternator: I. Current Electricity, II. Magnets from Electricity, III. Electricity from Magnets, IV. Energy Conversion. Field Test Edition.  

ERIC Educational Resources Information Center

This vocational physics individualized instructional student module on the alternator consists of the four units: Current electricity, magnets from electricity, electricity from magnets, and energy conversion. Designed with a laboratory orientation, the units present explanations of the concepts and experiments. Laboratory data sheets,…

Forsyth Technical Inst., Winston-Salem, NC.

20

Ocean wave energy conversion  

NASA Astrophysics Data System (ADS)

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

McCormick, M. E.

21

High-Order Sliding Control for a Wind Energy Conversion System Based on a Permanent Magnet Synchronous Generator  

Microsoft Academic Search

This paper presents the output power control of a wind energy conversion system (WECS) based on a permanent magnet synchronous generator (PMSG). It is assumed that the considered wind module integrates a stand-alone hybrid generation system, jointly with a battery bank, a variable ac load, and other generation subsystems. The operation strategy of the hybrid system determines two possible operation

F. Valenciaga; P. F. Puleston

2008-01-01

22

Study on variable speed direct drive wind energy conversion system with doubly salient electro-magnetic generator  

Microsoft Academic Search

This paper aims to discuss a novel variable speed direct drive wind energy conversion system (WECS) based on doubly salient electro-magnetic (DSEM) generator. The basic characteristic of the DSEM generator is firstly introduced. Then, for the relatively low speed of the rotor in large scale direct drive application, some special structures of the DSEM generator are presented. In order to

Jie Chen; Ran Chen; Chunying Gong; Zhihui Chen; Yangguang Yan

2008-01-01

23

Magnetohydrodynamics of atmospheric transients. IV. Nonplane two-dimensional analyses of energy conversion and magnetic field evolution  

SciTech Connect

The evolution of the magnetic field and the manner of conversion of thermal energy into different forms in the corona following a solar flare are examined by a nonplane magnetohydrodynamic (MHD) analysis. In the analysis all three components of magnetic field and velocity are treated in a physically self-consistent manner, with all physical variables as functions of time (t) and two spatial coordinates (r,theta). The difference due to the initial magnetic field, either twisted (force-free) or nontwisted (potential), is demonstrated. In both cases, of course, the field becomes non-force-free after the energy release, i.e., a flare. As in Papers I and II of this series, two initial field topologies (open vs. closed) are considered. The results show that the conversion of magnetic energy is faster for the case of the initially twisted (force-free) field in comparison with the initially untwisted (potential) field. Also, the twisted field produces a complex structure of the density enhancements. Comparison of the asymmetric topological evolution of the initially twisted magnetic fields with several white-light coronal transients (observed recently during the Solar Maximum year suggests that some preflare, magnetic topologies above the site of the energy release are nonpotential. This suggestion is based on the asymmetrial, somewhat concentric (''tennis racket'' shape), electron density enhancement obtained together with the twisted magnetic field lines in this study.

Wu, S.T.; Nakagama, Y.; Han, S.M.; Dryer, M.

1982-11-01

24

Direct Conversion of Energy.  

ERIC Educational Resources Information Center

|This publication is one of a series of information booklets for the general public published by the United States Atomic Energy Commission. Direct energy conversion involves energy transformation without moving parts. The concepts of direct and dynamic energy conversion plus the laws governing energy conversion are investigated. Among the topics…

Corliss, William R.

25

Research in Energy Conversion.  

National Technical Information Service (NTIS)

The results of investigations dealing with a broad spectrum of topics in energy conversion are presented. The individual studies are: Techniques for fabrication of large, thin silicon single crystals; Cathodes for thermionic energy conversion; Carnot-limi...

W. B. Nowak K. Weiss R. N. Wiener

1967-01-01

26

Perspectives on Permanent Magnetic Materials for Energy Conversion and Power Generation  

NASA Astrophysics Data System (ADS)

Permanent magnet development has historically been driven by the need to supply larger magnetic energy in ever smaller volumes for incorporation in an enormous variety of applications that include consumer products, transportation components, military hardware, and clean energy technologies such as wind turbine generators and hybrid vehicle regenerative motors. Since the 1960s, the so-called rare-earth "supermagnets," composed of iron, cobalt, and rare-earth elements such as Nd, Pr, and Sm, have accounted for the majority of global sales of high-energy-product permanent magnets for advanced applications. In rare-earth magnets, the transition-metal components provide high magnetization, and the rare-earth components contribute a very large magnetocrystalline anisotropy that donates high resistance to demagnetization. However, at the end of 2009, geopolitical influences created a worldwide strategic shortage of rare-earth elements that may be addressed, among other actions, through the development of rare-earth-free magnetic materials harnessing sources of magnetic anisotropy other than that provided by the rare-earth components. Materials engineering at the micron scale, nanoscale, and Angstrom scales, accompanied by improvements in the understanding and characterization of nanoscale magnetic phenomena, is anticipated to result in new types of permanent magnetic materials with superior performance.

Lewis, Laura H.; Jiménez-Villacorta, Félix

2013-01-01

27

Experiment on direct energy conversion from tandem mirror plasmas by using a slanted cusp magnetic field  

Microsoft Academic Search

A direct energy converter (DEC) designed for thermal ions escaping from a linear or near-linear device consists of a cusp magnetic field and decelerating electrodes. The electrons are deflected along the field lines and consequently separated from ions that are not fully magnetized. The ions are led to the decelerating electrodes to produce dc power. This type of DEC, the

Y. Yasaka; T. Yamamoto; Y. Kurumatani; H. Takeno; Y. Nakashima; T. Cho; Y. Tomita; M. Ishikawa

2008-01-01

28

A New Variable-Speed Wind Energy Conversion System Using Permanent-Magnet Synchronous Generator and Source Inverter  

Microsoft Academic Search

With the growth of wind energy conversion systems (WECSs), various technologies are developed for them. Permanent-magnet synchronous generators (PMSGs) are used by these technologies due to special characteristics of PMSGs such as low weight and volume, high performance, and the elimination of the gearbox. In this paper, a new variable-speed WECS with a PMSG and Z-source inverter is proposed. Characteristics

Seyed Mohammad Dehghan; Mustafa Mohamadian; Ali Yazdian Varjani

2009-01-01

29

Double objectives control for variable-speed wind energy conversion system with permanent magnet synchronous generator  

Microsoft Academic Search

It is the main objective for conventional variable-speed constant frequency wind energy conversion system (WECS) below the rated power to realize maximum power point tracking (MPPT). This paper presents a double objectives control scheme for WECS. Based on the frequency separation principle, the wind speed is divided into two components, a slowly varying component, named seasonal, and a rapidly varying

Feng Xu; Ming Cheng; Jianzhong Zhang; Zheng Wang

2010-01-01

30

Energy Conversion Technology.  

National Technical Information Service (NTIS)

This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: 'Hydrothermal Energy Conversion Technology' by David Robertson and Raymond J. LaSala; 'Materials for Geothermal Production' b...

D. Robertson R. J. LaSala

1992-01-01

31

A Permanent-Magnet Tubular Linear Generator for Ocean Wave Energy Conversion  

Microsoft Academic Search

This paper presents a novel permanent-magnet tubular linear generator (PMTLG) buoy system designed to convert the linear motion of ocean waves into electrical energy. The design incorporates no working seals and a saltwater air-gap bearing surface integration between the PMTLG buoy components. The internal generator design will be discussed, in addition to the system integration with the buoy structure. The

Joseph Prudell; Martin Stoddard; Ean Amon; Ted K. A. Brekken; Annette von Jouanne

2010-01-01

32

Observed signatures of magnetic energy conversion in solar flares and microflares  

NASA Astrophysics Data System (ADS)

A study of the evolution of X-ray output in different bipolar structures (Machado et al., 1988) is extended to weaker microflare activity in active regions. It is shown that, in solar flares and in weak flare-like transient brightenings, the energy release is triggered by the interaction of impacted bipolar regions. The results suggest that transient microflares may be responsible for a large fraction of the coronal heating in active regions. It is proposed that reconnection may act as a catalyst for the release of stored magnetic energy.

Mandrini, C. H.; Hernandez, A. M.; Rovira, M. G.; Machado, M. E.

33

Direct energy conversion  

Microsoft Academic Search

A comprehensive review of methods for direct energy conversion and energy storage is presented.Included are selected applications and brief reviews of underlying principles of each method. Principal chapter coverage is devoted to thermoelectric, photovoltaic, thermionic and magnetohydrodynamic generators. Other modes of energy conversion briefly covered are as follows: Nernst effect, ferroelectric, thermomagnetic, thermo-photo-voltaic, electrohydrodynamic, electrokinetic, piezoelectric, radiation, direct charging devices,

Angrist

1976-01-01

34

Photochemical Energy Conversion.  

ERIC Educational Resources Information Center

Describes procedures for two demonstrations: (1) photochemical energy conversion using ferric oxalate actinometry and (2) liquification of gases using Freon 114. Safety precautions are given for both demonstrations, as are procedures and material specifications. (JM)

Batschelet, William H.; George, Arnold

1986-01-01

35

Regional Energy Conversations Report  

NSDL National Science Digital Library

In 2009 and 2010, ATEEC facilitated a series of seven regional Energy Conversations. The primary purpose of the conversations was to obtain a snapshot view of existing and upcoming energy jobs and to determine which jobs are currently needed in different regions of the country, including the Mid-Atlantic, North Central, Northwest, South Central, Southeast, Southwest, and West. The resulting report on these Energy Conversations is intended to provide a preliminary labor market analysis and needs assessment. This information allows educational organizations to most effectively target regional energy industry requirements and to provide both short-and long-term education and training for the energy technicians of the 21st century workforce. Ultimately, this report should contribute to addressing the workforce development needs of business, industry, and government by providing educators with information needed to develop relevant curriculum that prepares students for energy technology careers.

2010-01-05

36

Session: Energy Conversion  

Microsoft Academic Search

This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Hydrothermal Energy Conversion Technology'' by David Robertson and Raymond J. LaSala; ''Materials for Geothermal Production'' by Lawrence E. Kukacka; ''Supersaturated Turbine Expansions for Binary Geothermal Power Plants'' by Carl J. Bliem; ''Geothermal Waster Treatment Biotechnology: Progress and Advantages to the Utilities''

David Robertson; Raymond J. LaSala; Lawrence E. Kukacka; Carl J. Bliem; Eugene T. Premuzic; John H. Weare

1992-01-01

37

Maximum power point tracking control and voltage regulation of a DC grid-tied wind energy conversion system based on a novel permanent magnet reluctance generator  

Microsoft Academic Search

This research paper aims to employ a new permanent magnet reluctance generator in a variable speed wind energy conversion system (WECS) of a grid-tied distributed generation application. The grid integration of WECS is achieved through cascaded dc-dc converters ensuring maximum power extraction from the wind energy while maintaining a constant output voltage at the grid side. The surplus power is

Kazmi Syed Muhammad Raza; Hiroki Goto; Hai-Jiao Guo; Osamu Ichinokura

2007-01-01

38

Linear intermode conversion of electromagnetic wave energy in a magnetically soft gyrotropic material  

Microsoft Academic Search

The excitation of axial radio-frequency (rf) magnetic induction by an axial rf current is observed in a conductor with circular\\u000a magnetic anisotropy when a weak magnetizing field is applied. The conductor is an amorphous cobalt-based wire, which exhibits\\u000a azimuthal magnetic anisotropy. It serves as the central conductor in a coaxial line. The axial rf magnetic induction produces\\u000a an emf in

A. S. Antonov; A. N. Lagar’kov; I. T. Yakubov

1999-01-01

39

BECON, Biomass Energy CONversion  

NSDL National Science Digital Library

How is biomass transformed into a usable fuel? This article, part of a series about the future of energy, discusses the BECON (Biomass Energy CONversion) facility, located in the state of Iowa. Here students read about methods used to produce alternative fuels from biomass. Copyright 2005 Eisenhower National Clearinghouse

Project, Iowa P.

2004-01-01

40

Session: Energy Conversion  

SciTech Connect

This session at the Geothermal Energy Program Review X: Geothermal Energy and the Utility Market consisted of five presentations: ''Hydrothermal Energy Conversion Technology'' by David Robertson and Raymond J. LaSala; ''Materials for Geothermal Production'' by Lawrence E. Kukacka; ''Supersaturated Turbine Expansions for Binary Geothermal Power Plants'' by Carl J. Bliem; ''Geothermal Waster Treatment Biotechnology: Progress and Advantages to the Utilities'' by Eugen T. Premuzic; and ''Geothermal Brine Chemistry Modeling Program'' by John H. Weare.

Robertson, David; LaSala, Raymond J.; Kukacka, Lawrence E.; Bliem, Carl J.; Premuzic, Eugene T.; Weare, John H.

1992-01-01

41

Laser energy conversion  

NASA Astrophysics Data System (ADS)

The conversion of laser energy to other, more useful, forms is an important element of any space power transmission system employing lasers. In general the user, at the receiving sight, will require the energy in a form other than laser radiation. In particular, conversion to rocket power and electricity are considered to be two major areas where one must consider various conversion techniques. Three systems (photovoltaic cells, MHD generators, and gas turbines) have been identified as the laser-to-electricity conversion systems that appear to meet most of the criteria for a space-based system. The laser thruster also shows considerable promise as a space propulsion system. At this time one cannot predict which of the three laser-to-electric converters will be best suited to particular mission needs. All three systems have some particular advantages, as well as disadvantages. It would be prudent to continue research on all three systems, as well as the laser rocket thruster. Research on novel energy conversion systems, such as the optical rectenna and the reverse free-electron laser, should continue due to their potential for high payoff.

Jalufka, N. W.

1989-07-01

42

Electromagnetic energy conversion at reconnection fronts.  

PubMed

Earth's magnetotail contains magnetic energy derived from the kinetic energy of the solar wind. Conversion of that energy back to particle energy ultimately powers Earth's auroras, heats the magnetospheric plasma, and energizes the Van Allen radiation belts. Where and how such electromagnetic energy conversion occurs has been unclear. Using a conjunction between eight spacecraft, we show that this conversion takes place within fronts of recently reconnected magnetic flux, predominantly at 1- to 10-electron inertial length scale, intense electrical current sheets (tens to hundreds of nanoamperes per square meter). Launched continually during intervals of geomagnetic activity, these reconnection outflow flux fronts convert ~10 to 100 gigawatts per square Earth radius of power, consistent with local magnetic flux transport, and a few times 10(15) joules of magnetic energy, consistent with global magnetotail flux reduction. PMID:24072917

Angelopoulos, V; Runov, A; Zhou, X-Z; Turner, D L; Kiehas, S A; Li, S-S; Shinohara, I

2013-09-27

43

Solar energy conversion.  

SciTech Connect

If solar energy is to become a practical alternative to fossil fuels, we must have efficient ways to convert photons into electricity, fuel, and heat. The need for better conversion technologies is a driving force behind many recent developments in biology, materials, and especially nanoscience. The Sun has the enormous untapped potential to supply our growing energy needs. The barrier to greater use of the solar resource is its high cost relative to the cost of fossil fuels, although the disparity will decrease with the rising prices of fossil fuels and the rising costs of mitigating their impact on the environment and climate. The cost of solar energy is directly related to the low conversion efficiency, the modest energy density of solar radiation, and the costly materials currently required. The development of materials and methods to improve solar energy conversion is primarily a scientific challenge: Breakthroughs in fundamental understanding ought to enable marked progress. There is plenty of room for improvement, since photovoltaic conversion efficiencies for inexpensive organic and dye-sensitized solar cells are currently about 10% or less, the conversion efficiency of photosynthesis is less than 1%, and the best solar thermal efficiency is 30%. The theoretical limits suggest that we can do much better. Solar conversion is a young science. Its major growth began in the 1970s, spurred by the oil crisis that highlighted the pervasive importance of energy to our personal, social, economic, and political lives. In contrast, fossil-fuel science has developed over more than 250 years, stimulated by the Industrial Revolution and the promise of abundant fossil fuels. The science of thermodynamics, for example, is intimately intertwined with the development of the steam engine. The Carnot cycle, the mechanical equivalent of heat, and entropy all played starring roles in the development of thermodynamics and the technology of heat engines. Solar-energy science faces an equally rich future, with nanoscience enabling the discovery of the guiding principles of photonic energy conversion and their use in the development of cost-competitive new technologies.

Crabtree, G. W.; Lewis, N. S. (Materials Science Division); (California Inst. of Tech.)

2008-03-01

44

Electromechanical Energy Conversion.  

ERIC Educational Resources Information Center

This programed text on electromechanical energy conversion (motors and generators) was developed under contract with the U.S. Office of Education as Number 12 in a series of materials for use in an electrical engineering sequence. It is intended to be used in conjunction with other materials and with other short texts in the series. (DH)

LePage, Wilbur R.

45

Mechanochemical Energy Conversion  

ERIC Educational Resources Information Center

Summarizes the thermodynamics of macromolecular systems, including theories and experiments of cyclic energy conversion with rubber and collagen as working substances. Indicates that an early introduction into the concept of chemical potential and solution thermodynamics is made possible through the study of the cyclic processes. (CC)

Pines, E.; And Others

1973-01-01

46

Solar energy conversion unit  

Microsoft Academic Search

A solar energy converter is provided in the form of a unit for assembly together with other similar units to build up a solarenergy conversion installation. Each unit includes a fixed support structure, a mounting element articulated on the support structure, and an optical concentrator carried by the mounting element. The optical concentrator consists of a plurality of coplanar, spherical

M. Palazzetti; C. Ponti; P. L. Tenci

1981-01-01

47

Oscillating Wind Energy Conversion Systems.  

National Technical Information Service (NTIS)

The information in this document suggests that Oscillating Wind Energy Conversion Systems do not appear to have any significant advantages over equivalent conventional rotating-element wind energy conversion systems. In fact, in most cases it appears that...

P. South R. Mitchell

1983-01-01

48

Autonomous renewable energy conversion system  

Microsoft Academic Search

This paper briefly reviews the need for renewable power generation and describes a medium-power Autonomous Renewable Energy Conversion System (ARECS), integrating conversion of wind and solar energy sources. The objectives of the paper are to extract maximum power from the proposed wind energy conversion scheme and to transfer this power and the power derived by the photovoltaic system in a

Ventzislav Valtchev; Alex Van den Bossche; Jozef Ghijselen; Jan Melkebeek

2000-01-01

49

Advanced solar energy conversion  

NASA Astrophysics Data System (ADS)

An atomic iodine laser, a candidate for the direct solar pumped lasers, was successfully excited with a 4 kW beam from a xenon arc solar simulator, thus proving the feasibility of the concept. The experimental set up and the laser output as functions of operating conditions are presented. The preliminary results of the iodine laser amplifier pumped with the HCP array to which a Q switch for giant pulse production was coupled are included. Two invention disclosures - a laser driven magnetohydrodynamic generator for conversion of laser energy to electricity and solar pumped gas lasers - are also included.

Lee, J. H.

1981-08-01

50

Instantaneous torque ripple control and maximum power extraction in a permanent magnet reluctance generator driven wind energy conversion system  

Microsoft Academic Search

A usual wind energy conversion system (WECS) suffers from significant amount of torque ripples even if the wind velocity remains constant. These torque ripples propagate mechanical stress in the turbine-generator drive train and may eventually lead to the failure of its various components. This research paper presents a unified control strategy which yields maximum power from WECS while minimizing the

Erkan Sunan; Kazmi Syed Muhammad Raza; Hiroki Goto; Hai-Jiao Guo; O. Ichinokur

2010-01-01

51

Solar energy conversion unit  

SciTech Connect

A solar energy converter is provided in the form of a unit for assembly together with other similar units to build up a solarenergy conversion installation. Each unit includes a fixed support structure, a mounting element articulated on the support structure, and an optical concentrator carried by the mounting element. The optical concentrator consists of a plurality of coplanar, spherical lenses the centers of which are located at the vertices of a polygon. The center of the polygon lies on a line extending perpendicularly to the plane of the lenses through the point of articulation of the mounting element on the support structure. Each unit further includes a plurality of converter modules located at the foci of respective ones of the spherical lenses and carried by respective connecting legs which extend from the mounting element. Each converter module includes a photovoltaic cell and means for transferring the heat dissipated in the photovoltaic cell to a liquid.

Palazzetti, M.; Ponti, C.; Tenci, P.L.

1981-07-28

52

Wind energy conversion system  

SciTech Connect

This patent describes a wind energy conversion system comprising: a propeller rotatable by force of wind; a generator of electricity mechanically coupled to the propeller for converting power of the wind to electric power for use by an electric load; means coupled between the generator and the electric load for varying the electric power drawn by the electric load to alter the electric loading of the generator; means for electro-optically sensing the speed of the wind at a location upwind from the propeller; and means coupled between the sensing means and the power varying means for operating the power varying means to adjust the electric load of the generator in accordance with a sensed value of wind speed to thereby obtain a desired ratio of wind speed to the speed of a tip of a blade of the propeller.

Longrigg, P.

1987-03-17

53

Review of direct energy conversion for fusion reactors  

Microsoft Academic Search

The direct conversion to electrical energy of the energy carried by the leakage plasma from a fusion reactor and by the ions that are not converted to neutrals in a neutral-beam injector is discussed. The conversion process is electrostatic deceleration and direct particle collection as distinct from plasma expansion against a time-varying magnetic field or conversion in an EXB duct

W. L. Barr; R. W. Moir

1976-01-01

54

Oscillating wind energy conversion systems  

Microsoft Academic Search

The oscillating cable type wind energy conversion system and the oscillating vane and the oscillating wind are addressed. The advantages and disadvantages of each type of system are evaluated, and each is compared with a conventional rotating element wind energy conversion device. It appears unlikely that any of the oscillating element concepts can compete with the present generation of conventional

P. South; R. Mitchell

1983-01-01

55

Magnetic Energy  

Microsoft Academic Search

I WOULD like to comment, if rather tardily, on one paragraph of Prof. Ferraro's review1 of my book, Electromagnetism and Relativity2. He says: ``Prof. Cullwick appears to be under a misapprehension about the nature of the magnetic energy of a system of electric currents... we read that `the hypothesis is introduced that the magnetic energy of a current circuit is

E. G. Cullwick

1961-01-01

56

Direct energy conversion for fusion power  

Microsoft Academic Search

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

G. H. Miley

1980-01-01

57

Energy conversion and storage program  

NASA Astrophysics Data System (ADS)

The Energy Conversion and Storage Program applies chemical and chemical engineering principles to solve problems in (1) production of new synthetic fuels; (2) development of high-performance rechargeable batteries and fuel cells; (3) development of advanced thermochemical processes for energy storage; (4) characterization of complex chemical processes; and (5) the application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, and advanced methods of analysis. The following five areas are discussed: electrochemical energy storage and conversion; microstructured materials; biotechnology; fossil fuels; and high temperature superconducting processing. Papers have been processed separately for inclusion on the data base.

1990-12-01

58

Direct energy conversion of radiation energy in fusion reactor  

Microsoft Academic Search

Direct energy conversion from plasma heat flux has been studied. Since major parts of fusion energy in the advanced fusion reactor are radiation and charged particle energies, the flexible design of the blanket is possible. We discuss the potentiality of the thermoelectric element that generates electricity by temperature gradient in conductors. A strong magnetic field is used to confine the

S. Yamaguchi; A. Iiyoshi; O. Motojima; M. Okamoto; S. Sudo; M. Ohnishi; M. Onozuka; C. Uenosono

1993-01-01

59

Conversion of radiant energy into chemical energy  

Microsoft Academic Search

The conversion of light into chemical energy as well as the conversion of chemical energy into light leads to exciting speculations and experiments. Reversible photoredox reactions appear to be the most promising chemical system for converting solar energy into chemical or electrochemical energy. Finding selective electrode material in photogalvanic cells is one of the problems to be solved. Selective electrode

G. Calzaferri

1978-01-01

60

On the energy conversion efficiency in magnetic hyperthermia applications: A new perspective to analyze the departure from the linear regime  

NASA Astrophysics Data System (ADS)

The success of magnetic hyperthermia cancer treatments rely strongly on the magnetic properties of the nanoparticles and their intricate dependence on the externally applied field. This is particularly more so as the response departs from the low field linear regime. In this paper we introduce a new parameter, referred to as the efficiency in converting electromagnetic energy into thermal energy, which is shown to be remarkably useful in the analysis of the system response, especially when the power loss is investigated as a function of the applied field amplitude. Using numerical simulations of dynamic hysteresis, through the stochastic Landau-Lifshitz model, we map in detail the efficiency as a function of all relevant parameters of the system and compare the results with simple--yet powerful--predictions based on heuristic arguments about the relaxation time.

Landi, G. T.; Bakuzis, A. F.

2012-04-01

61

Research in Photochemical Energy Conversion.  

National Technical Information Service (NTIS)

The results of investigations dealing with the following topics in photochemical energy conversion are presented: Apparatus for Photochemical Studies; Studies of Charge Transfer Systems; The Photochemistry of Perinaphthenone; The Photoreduction of Phenant...

K. Weiss

1971-01-01

62

Energy conversion system  

SciTech Connect

A thermal-mechanical energy converting device is disclosed that has at least two rotatably supported wheels and with one or more endless transmission elements of a material having a memory effect capable in the bending mode of converting thermal energy into mechanical energy when heated from a temperature below its transition temperature to a temperature above its transition temperature; the transmission elements serve to drive one wheel from the other wheel upon application of thermal energy to the transmission elements, whereby the thermal energy is transferred from the other wheel to the transmission elements over at least a major portion of the circumferential contact of the transmission elements with the other wheel.

Wang, F.E.

1981-06-30

63

Energy conversion engine  

SciTech Connect

Fuelless means of obtaining energy comprising: (A description is given of a) a cellular conveyor means for carrying air at atmospheric pressure down to great water depths and converting it to stored energy in the form of compressed air; (B) open bottom bell type container for capturing the compressed air; and (C) means for converting the stored energy to pratical use by driving a turbine wheel through the use of a pressure container and a nozzle arrangement.

Grande, M.

1980-07-08

64

Particle Discrimination Experiment for Direct Energy Conversion  

Microsoft Academic Search

A direct energy conversion system designed for D-³He fusion reactor based on a field reversed configuration employs a venetian-blind type converter for thermal ions to produce DC power and a traveling wave type converter for fusion protons to produce RF power. It is therefore necessary to separate, discriminate, and guide the particle species. For this purpose, a cusp magnetic field

Y. Yasaka; Y. Kiriyama; S. Yamamoto; H. Takeno; M. Ishikawa

2005-01-01

65

Energy Conversion and Storage Program  

SciTech Connect

The Energy Conversion and Storage Program applies chemistry and materials science principles to solve problems in (1) production of new synthetic fuels, (2) development of high-performance rechargeable batteries and fuel cells, (3) development of advanced thermochemical processes for energy conversion, (4) characterization of complex chemical processes, and (5) application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis. Electrochemistry research aims to develop advanced power systems for electric vehicle and stationary energy storage applications. Topics include identification of new electrochemical couples for advanced rechargeable batteries, improvements in battery and fuel-cell materials, and the establishment of engineering principles applicable to electrochemical energy storage and conversion. Chemical Applications research includes topics such as separations, catalysis, fuels, and chemical analyses. Included in this program area are projects to develop improved, energy-efficient methods for processing waste streams from synfuel plants and coal gasifiers. Other research projects seek to identify and characterize the constituents of liquid fuel-system streams and to devise energy-efficient means for their separation. Materials Applications research includes the evaluation of the properties of advanced materials, as well as the development of novel preparation techniques. For example, the use of advanced techniques, such as sputtering and laser ablation, are being used to produce high-temperature superconducting films.

Cairns, E.J.

1992-03-01

66

Implanted Energy Conversion System.  

National Technical Information Service (NTIS)

The Richland Energy Laboratory heart power source combines the high efficiency of Stirling engines with the reliability, efficiency, and flexibility of hydraulic power transfer and control to ensure long system life and physiological effectiveness. Extend...

R. P. Johnston L. P. Bakker A. Bennett C. R. Blair S. G. Emigh

1976-01-01

67

Photochemical conversion of solar energy.  

PubMed

Energy is the most important issue of the 21st century. About 85% of our energy comes from fossil fuels, a finite resource unevenly distributed beneath the Earth's surface. Reserves of fossil fuels are progressively decreasing, and their continued use produces harmful effects such as pollution that threatens human health and greenhouse gases associated with global warming. Prompt global action to solve the energy crisis is therefore needed. To pursue such an action, we are urged to save energy and to use energy in more efficient ways, but we are also forced to find alternative energy sources, the most convenient of which is solar energy for several reasons. The sun continuously provides the Earth with a huge amount of energy, fairly distributed all over the world. Its enormous potential as a clean, abundant, and economical energy source, however, cannot be exploited unless it is converted into useful forms of energy. This Review starts with a brief description of the mechanism at the basis of the natural photosynthesis and, then, reports the results obtained so far in the field of photochemical conversion of solar energy. The "grand challenge" for chemists is to find a convenient means for artificial conversion of solar energy into fuels. If chemists succeed to create an artificial photosynthetic process, "... life and civilization will continue as long as the sun shines!", as the Italian scientist Giacomo Ciamician forecast almost one hundred years ago. PMID:18605661

Balzani, Vincenzo; Credi, Alberto; Venturi, Margherita

2008-01-01

68

Energy conversion in photosynthesis  

NASA Astrophysics Data System (ADS)

Photosystem II (PSII) uses light energy to split water into protons, electrons and O2 [1]. In this reaction, Nature has solved the difficult chemical problem of efficient four-electron oxidation of water to yield O2 without significant side reactions. In order to use Nature's solution for the design of materials that split water for solar fuel production, it is important to understand the mechanism of the reaction. The X ray crystal structures of cyanobacterial PSII provide information on the structure of the Mn and Ca ions, the redox-active tyrosine called YZ, and the surrounding amino acids that comprise the O2 evolving complex (OEC) [2,3]. We have used computational studies used to refine the structure of the OEC to obtain a complete structural model of the OEC that is in agreement with spectroscopic data [4,5]. The structure of the OEC and the mechanism of water oxidation by PSII will be discussed in the light of biophysical and computational studies, inorganic chemistry and X-ray crystallographic information. [4pt] [1] J.P. McEvoy and G.W. Brudvig, Chem. Rev. (2006) 106, 4455-4483. [0pt] [2] K.N. Ferreira et al., Science (2004) 303, 1831-1838. [0pt] [3] B. Loll et al., Nature (2006) 438, 1040-1044. [0pt] [4] E.M. Sproviero et al., J. Am. Chem. Soc. (2008) 130, 6728-6730. [0pt] [5] E.M. Sproviero et al., J. Am. Chem. Soc. (2008) 130, 3428-3442.

Brudvig, Gary

2011-03-01

69

Plasmonic nanorectennas for energy conversion  

NASA Astrophysics Data System (ADS)

There is renewed interest in using rectennas (consisting of an antenna coupled to a rectifying diode) for energy conversion applications. Progress in nanofabrication has enabled nanoscale devices to be fabricated, such that "nanoantennas" exist that resonate at visible/near-infrared (vis/nir) wavelengths, and ultrafast "nanodiodes" exist that can rectify vis/nir frequencies (above 1014 Hz). Photon energies are so high at these frequencies that existing theories of diode responsivity may not apply, justifying new simulations and experiments. We present modeling and experiments of nanoantenna-coupled nanodiodes, such as metal-insulator-metal structures, and discuss how our findings influence models of energy conversion in these structures. We simulate and measure the properties of potential nanorectennas such as gold nanowires on ultrathin insulators.

Osgood, Richard, III; Carlson, Joel B.; Kimball, Brian R.; Ziegler, David P.; Welch, James R.; Belton, Lauren E.; Fernandes, Gustavo E.; Liu, Zhijun; Xu, Jimmy

2009-08-01

70

Available work energy and coal conversion processes  

Microsoft Academic Search

The available work energy for coal conversion processes as derived from the second law of thermodynamics was examined to provide the relationship between operating conditions and useful energy recovery. The concept of total energy recovery and the available work energy loss was applied to each of the process units in various coal conversion processes. The coal conversion processes which were

C. Y. Lin

1977-01-01

71

Biomass conversion processes for energy and fuels  

Microsoft Academic Search

The book treats biomass sources, promising processes for the conversion of biomass into energy and fuels, and the technical and economic considerations in biomass conversion. Sources of biomass examined include crop residues and municipal, animal and industrial wastes, agricultural and forestry residues, aquatic biomass, marine biomass and silvicultural energy farms. Processes for biomass energy and fuel conversion by direct combustion

S. S. Sofer; O. R. Zaborsky

1981-01-01

72

Conversion of magnetic energy via collisionless tearing modes: Applicability of existing theories to observations in the Earth's magnetotail  

Microsoft Academic Search

Magnetohydrodynamic reconnection theories and kinetic theories of the collisionless tearing mode instability are surveyed. Any collisional reconnection model requires existence of an anomalous resistivity. However, this requirement seems difficult to obtain in the real magnetotail. For the concept of ion tearing instability to be valid, the contribution of magnetized electrons should be supressed by a physical mechanism, such as a

A. Nishida; T. Terasawa; M. Hoshino

1986-01-01

73

Extrinsic Field Acceleration of the Magnetic Parahydrogen Conversion.  

National Technical Information Service (NTIS)

The magnetic mechanism parahydrogen conversion, catalyzed by chromia, has been found to be accelerated by an extrinsic magnetic field. The effect may be observed over ruby (a dilute solid solution of chromia in alpha-alumina), over various surface concent...

M. Misono P. W. Selwood

1968-01-01

74

Magnetic Materials in sustainable energy  

NASA Astrophysics Data System (ADS)

A new energy paradigm, consisting of greater reliance on renewable energy sources and increased concern for energy efficiency in the total energy lifecycle, has accelerated research in energy-related technologies. Due to their ubiquity, magnetic materials play an important role in improving the efficiency and performance of devices in electric power generation, conversion and transportation. Magnetic materials are essential components of energy applications (i.e. motors, generators, transformers, actuators, etc.) and improvements in magnetic materials will have significant impact in this area, on par with many ``hot'' energy materials efforts. The talk focuses on the state-of-the-art hard and soft magnets and magnetocaloric materials with an emphasis on their optimization for energy applications. Specifically, the impact of hard magnets on electric motor and transportation technologies, of soft magnetic materials on electricity generation and conversion technologies, and of magnetocaloric materials for refrigeration technologies, will be discussed. The synthesis, characterization, and property evaluation of the materials, with an emphasis on structure-property relationships, will be examined in the context of their respective markets as well as their potential impact on energy efficiency. Finally, considering future bottle-necks in raw materials and in the supply chain, options for recycling of rare-earth metals will be analyzed.ootnotetextO. Gutfleisch, J.P. Liu, M. Willard, E. Bruck, C. Chen, S.G. Shankar, Magnetic Materials and Devices for the 21st Century: Stronger, Lighter, and More Energy Efficient (review), Adv. Mat. 23 (2011) 821-842.

Gutfleisch, Oliver

2012-02-01

75

Biomass conversion processes for energy and fuels  

SciTech Connect

The book treats biomass sources, promising processes for the conversion of biomass into energy and fuels, and the technical and economic considerations in biomass conversion. Sources of biomass examined include crop residues and municipal, animal and industrial wastes, agricultural and forestry residues, aquatic biomass, marine biomass and silvicultural energy farms. Processes for biomass energy and fuel conversion by direct combustion (the Andco-Torrax system), thermochemical conversion (flash pyrolysis, carboxylolysis, pyrolysis, Purox process, gasification and syngas recycling) and biochemical conversion (anaerobic digestion, methanogenesis and ethanol fermentation) are discussed, and mass and energy balances are presented for each system.

Sofer, S.S.; Zaborsky, O.R.

1981-01-01

76

Biomass conversion processes for energy and fuels  

NASA Astrophysics Data System (ADS)

The book treats biomass sources, promising processes for the conversion of biomass into energy and fuels, and the technical and economic considerations in biomass conversion. Sources of biomass examined include crop residues and municipal, animal and industrial wastes, agricultural and forestry residues, aquatic biomass, marine biomass and silvicultural energy farms. Processes for biomass energy and fuel conversion by direct combustion (the Andco-Torrax system), thermochemical conversion (flash pyrolysis, carboxylolysis, pyrolysis, Purox process, gasification and syngas recycling) and biochemical conversion (anaerobic digestion, methanogenesis and ethanol fermentation) are discussed, and mass and energy balances are presented for each system.

Sofer, S. S.; Zaborsky, O. R.

77

Fundamentals of solar energy conversion  

NASA Astrophysics Data System (ADS)

This textbook strives to strengthen a student's knowledge of the basic sciences as well as to provide a practical background in solar energy conversion. Particular consideration is given to solar geometry, the availability of solar energy, solar concentrators, elements of fluid mechanics and heat transfer in solar systems, flat-plate collectors, and thermal storage of solar energy. The use of solar energy for specific types of loads is then discussed. The application of active solar systems to space and hot-water heating is considered, and a description is given of the empirical f-chart method for thermal-performance analysis. The economics of solar systems is examined along with the application of solar energy to cooling and dehumidification loads as well as the application of solar energy to industrial and other thermal loads. The concept of passive systems is explained, and the evaluation of thermal performance on the basis of the empirical load/collector ratio method is described. Appendixes are presented with such information as solar-position charts, tables of solar radiation and climatic data, and programs for hand-held calculators.

Anderson, E. E.

78

Ocean thermal-energy conversion  

NASA Astrophysics Data System (ADS)

The principles underlying ocean thermal-energy conversion (OTEC) are reviewed, and a schematic layout of a system is included. The two systems currently under study, the open system and the closed system, are described. The prospect now, it is noted, is that OTEC plants will not be commercially viable on a widespread basis, even in the tropics. This is especially true of the large-scale plants that have been envisioned. A strong possibility is seen, however, that smaller plants, generating about 40 megawatts of electrical power, can survive commercially. The following conditions would favor their success: placement on land rather than at sea; placement in areas (such as islands) where alternative energy supplies are at a premium; and designing the plant to operate in conjunction with either an aquaculture or a desalination plant.

Ford, G.; Niblett, C.; Walker, L.

1983-03-01

79

Matching a Permanent Magnet Synchronous Generator to a Fixed Pitch Vertical Axis Turbine for Marine Current Energy Conversion  

Microsoft Academic Search

Extracting energy from a free-flow marine current using a vertical axis fixed pitch turbine requires a generator that can handle varying speeds and loads, since such a turbine gives maximum power capture for a fixed tip speed ratio. A prototype of such a generator has been designed and constructed. In this paper, its variable speed and load operation is evaluated,

Katarina Yuen; Karin Thomas; MÅrten Grabbe; Paul Deglaire; Mathias Bouquerel; David Osterberg; Mats Leijon

2009-01-01

80

Neutrino conversions in solar random magnetic fields  

NASA Astrophysics Data System (ADS)

We consider the effect of a random magnetic field in the convective zone of the Sun superimposed to a regular magnetic field on resonant neutrino spin-flavor oscillations. We argue for the existence of a field of strongly chaotic nature at the bottom of the convective zone. In contrast to previous attempts we employ a model motivated regular magnetic field profile: it is a static field solution to the solar equilibrium hydro-magnetic equations. These solutions have been known for a long time in the literature. We show for the first time that in addition they are twisting solutions. In this scenario electron antineutrinos are produced through cascades like ?eL-->??L-- >?~eR, The detection of ?~eR at Earth would be a long-awaited signature of the Majorana nature of the neutrino. The expected signals in the different experiments (SK, GALLEX-SAGE, Homestake) are obtained as a function of the level of noise, regular magnetic field and neutrino mixing parameters. Previous results obtained for small mixing and ad-hoc regular magnetic profiles are reobtained. We confirm the strong suppression for a large part of the parameter space of the ?~eR-flux for high energy boron neutrinos in agreement with present data of the SK experiment. We find that MSW (Mikheyev-Smirnov-Wolfenstein) regions (?m2~=10-5 eV2, both small and large mixing solutions) are stable up to very large levels of noise (P=0.7-0.8) but they are acceptable from the point of view of antineutrino production only for moderate levels of noise (P~=0.95). For strong noise and a reasonable regular magnetic field, any parameter region (?m2, sin 2 2?) is excluded. As a consequence, we are allowed to reverse the problem and to put limits on the r.m.s. field strength and transition magnetic moments by demanding a particle physics solution to the SNP in this scenario.

Semikoz, V. B.; Torrente-Lujan, E.

1999-09-01

81

The upper limit to solar energy conversion  

Microsoft Academic Search

Petela carried out research to determine the maximum ideal theoretical work output obtainable from BR independent of any conversion device. However, omnicolor conversion is considered by many to be the ideal theoretical process for solar energy conversion. Petela's result for blackbody radiation (BR) exergy is often thought to be of little importance because it appears to neglect fundamental theoretical issues

Sean E. Wright; David S. Scott; James B. Haddow; Marc A. Rosen

2000-01-01

82

Heliostatic solar energy conversion system  

SciTech Connect

A heliostatic solar energy conversion system in which a plurality of multi-faceted heliostats are supported on one or more platforms that move in a segment of a circular path about a central receiver as a center. The heliostats are mounted in frames that pivot on the platform on an edge of each heliostat. In one embodiment the platforms are supported in a concave spherical depression in the ground. The heliostats of the invention are constructed with a plurality of intersecting beams and stringers, and the stringers are formed with parabolic flanges which support the facets so that the angle of incidence between the sun and the focal point of the central receiver is generally in the center of each facet. A vernier adjustment is provided for each heliostat.

Jones, D.

1982-12-28

83

WELMM analysis and solar energy conversion systems  

Microsoft Academic Search

The application of the WELMM (water, energy, land, materials, manpower) systems approach to the analysis of the competitiveness of solar energy conversion systems is discussed. Economic analyses of solar energy conversion systems are shown to depend on the values of parameters (interest and inflation rates and the price of petroleum) which are difficult to predict over the long term. The

J.-L. Abatut

1979-01-01

84

Biological Solar Energy Conversion and U.S. Energy Policy  

ERIC Educational Resources Information Center

|Surveys energy consumption in the United States and explores the possibility of increasing the amount of energy obtained from biomass conversion (biologically produced energy). Economic and environmental concerns of biomass conversion processes are discussed. (CP)|

Pimentel, David; And Others

1978-01-01

85

Metallurgical technologies, energy conversion, and magnetohydrodynamic flows  

SciTech Connect

The present volume discusses metallurgical applications of MHD, R D on MHD devices employing liquid working medium for process applications, electromagnetic (EM) modulation of molten metal flow, EM pump performance of superconducting MHD devices, induction EM alkali-metal pumps, a physical model for EM-driven flow in channel-induction furnaces, grain refinement in Al alloys via EM vibrational method, dendrite growth of solidifying metal in dc magnetic field, MHD for mass and heat transfer in single-crystal melt growth, inverse EM shaping, and liquid-metal MHD development in Israel. Also discussed are the embrittlement of steel by lead, an open cycle MHD disk generator, the acceleration of gas-liquid piston flows for molten-metal MHD generators, MHD flow around a cylinder, new MHD drag coefficients, liquid-metal MHD two-phase flow, and two-phase liquid gas mixers for MHD energy conversion.

Branover, H.; Unger, Y.

1993-01-01

86

Solar energy conversion by water photodissociation  

Microsoft Academic Search

Some aspects of the photochemical conversion of solar energy by simple nonbiological systems are discussed. The basic concepts of direct and catalyzed photodissociation of water are outlined. Water dissociation in closed-cycle processes based on endothermic photochemical reactions offers a potential solution to the problem of solar energy conversion. It is shown that transition metal commplexes whose excited state chemistry is

V. Balzani; L. Moggi; M. F. Manfrin; F. Bolletta; M. Gleria

1975-01-01

87

Screening method for wind energy conversion systems  

Microsoft Academic Search

A screening method is presented for evaluating wind energy conversion systems (WECS) logically and consistently. It is a set of procedures supported by a data base for large conventional WECS. The procedures are flexible enough to accommodate concepts lacking cost and engineering detail, as is the case with many innovative wind energy conversion systems (IWECS) The method uses both value

R. D. McConnell

1980-01-01

88

Extrinsic Field Acceleration of the Magnetic Parahydrogen Conversion.  

National Technical Information Service (NTIS)

An example of increased reaction velocity observed on application of an extrinsic magnetic field is reported. The reaction was the heterogeneous catalytic parahydrogen conversion which, under the conditions and as shown by the absence of measurable hydrog...

M. Misono P. W. Selwood

1968-01-01

89

Research on Electrochemical Energy Conversion Systems.  

National Technical Information Service (NTIS)

The investigation of electrochemical energy conversion systems has involved work on three tasks. The first deal with high energy galvanic cells of the type applicable to vehicle propulsion. Attention has been directed toward the cathode depolarizer proble...

R. T. Foley D. H. Bomkamp C. D. Thompson

1970-01-01

90

Technology Assessment of Wind Energy Conversion Systems.  

National Technical Information Service (NTIS)

Environmental data for Wind Energy Conversion Systems (WECSs) have been generated in support of the Technology Assessment of Solar Energy (TASE) program. Two candidates have been chosen to characterize the WECS that might be deployed if this technology ma...

R. W. Meier T. J. Merson

1979-01-01

91

Technology Assessment of Wind Energy Conversion Systems.  

National Technical Information Service (NTIS)

Environmental data for wind energy conversion systems (WECSs) have been generated in support of the Technology Assessment of Solar Energy (TASE) program. Two candidates have been chosen to characterize the WECS that might be deployed if this technology ma...

B. W. Meier T. J. Merson

1980-01-01

92

High temperature thermoelectric energy conversion  

NASA Astrophysics Data System (ADS)

The theory and current status of materials research for high-temperature thermoelectric energy conversion are reviewed. Semiconductors are shown to be the preferred class of materials for this application. Optimization of the figure of merit of both broadband and narrow-band semiconductors is discussed as a function of temperature. Phonon scattering mechanisms are discussed, and basic material guidelines are given for reduction of thermal conductivity. Two general classes of materials show promise for high temperature figure of merit (Z) values, namely the rare earth chalcogenides and the boron-rich borides. The electronic transport properties of the rare earth chalcogenides are explicable on the basis of degenerate or partially degenerate n-type semiconductors. Boron and boron-rich borides exhibit p-type hopping conductivity, with detailed explanations proposed for the transport differing from compound to compound. Some discussion is presented on the reasons for the low thermal conductivities in these materials. Also, ZTs greater than one appear to have been realized at high temperature in many of these compounds.

Wood, Charles

93

Carbon nanostructures for solar energy conversion schemes.  

PubMed

Developing environmentally friendly, renewable energy is one of the challenges to society in the 21st century. One of the renewable energy technologies is solar energy conversion--a technology that directly converts daylight into electricity. This highlight surveys recent breakthroughs in the field of implementing carbon nanostructures--fullerenes (0D), carbon nanotubes (1D), carbon nanohorns, and graphene (2D)--into solar energy conversion schemes, that is, bulk heterojunction and dye-sensitized solar cells. PMID:20871887

Guldi, Dirk M; Sgobba, Vito

2010-09-27

94

Compact harsh environment energy conversion systems  

NASA Astrophysics Data System (ADS)

The quest for energy is leading the industry into drilling deeper wells. Typically, a temperature gradient of 1°C/150 ft can be expected, with bottom hole temperatures reaching beyond 200°C in many areas of the world. Moreover, the increased recovery benefits and cost reductions possible with the use of horizontal and multilateral wells has triggered a need for higher power energy conversion systems in bottom hole assemblies, such as rotary steerable tools and downhole tractors. The concepts developed throughout this work address some of these new needs. This research investigated improvements, novel solutions and considerations that will lead to significant advantages in terms of reliability, extended temperature operation, increased power capability and reduced size and cost of compact harsh environment energy conversion systems. Improvements to both the electromechanical subsystem and the power electronic subsystem are introduced. Air gap viscous losses were shown to a have a significant effect on the optimal design of submersible PM (permanent magnet) machines, and a design procedure to account for this loss component in the design was developed. The application of a dual winding exterior rotor PM machine in a downhole environment enabled a significant increase in the application's torque capability, provided protection against generator winding over voltage, and reduced parts count. Comprehensive switching device qualification, testing, and simulation lead to a simple failure mitigation technique for the operation of the most suitable devices at elevated temperature. A flying capacitor multilevel inverter was then successfully constructed and temperature tested. A novel motor drive concept suited for elevated temperature oil filled environment applications concluded the research.

Ahmed, Shehab

95

Energy conversion & storage program. 1994 annual report  

SciTech Connect

The Energy Conversion and Storage Program investigates state-of-the-art electrochemistry, chemistry, and materials science technologies for: (1) development of high-performance rechargeable batteries and fuel cells; (2) development of high-efficiency thermochemical processes for energy conversion; (3) characterization of complex chemical processes and chemical species; (4) study and application of novel materials for energy conversion and transmission. Research projects focus on transport process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis.

Cairns, E.J.

1995-04-01

96

Solar-wind energy conversion system  

Microsoft Academic Search

A combined solar-wind energy conversion system in which the combined effects of solar and wind energy are utilized in raising water from a lower to an upper water storage tank to increase its potential energy for generation of electricity. Incoming solar energy heats water to form steam which is temporarily stored. The stored steam is vented to one of first

1984-01-01

97

Solar-wind energy conversion system  

Microsoft Academic Search

A combined solar-wind energy conversion system in which the combined effects of solar and wind energy are utilized in raising water from a lower to an upper water storage tank to increase its potential energy for generation of electricity. Incoming solar energy heats water to form steam which is temporarily stored. The stored steam is vented to one of first

1982-01-01

98

Energy Conversion in Natural and Artificial Photosynthesis  

PubMed Central

Summary Modern civilization is dependent upon fossil fuels, a nonrenewable energy source originally provided by the storage of solar energy. Fossil fuel dependence has severe consequences including energy security issues and greenhouse gas emissions. The consequences of fossil fuel dependence could be avoided by fuel-producing artificial systems that mimic natural photosynthesis, directly converting solar energy to fuel. This review describes the three key components of solar energy conversion in photosynthesis: light harvesting, charge separation, and catalysis. These processes are compared in natural and artificial systems. Such a comparison can assist in understanding the general principles of photosynthesis and in developing working devices including photoelectrochemical cells for solar energy conversion.

McConnell, Iain; Li, Gonghu; Brudvig, Gary W.

2010-01-01

99

Evaluation of Power Extraction to Linear Gain Scheduling Controllers in a Small Wind Energy Conversion System  

Microsoft Academic Search

Renewable energy sources have focused a special attention in wind energy conversion systems, where the goal is maximal power extraction. This paper presents an evaluation of the linear controllers eigen structure assignment, linear quadratic regulator, and the robust loop shaping design procedure actuating on a small wind energy conversion system with a permanent magnet synchronous generator, the rectification is made

S. S. Acevedo; Eduardo Giraldo; Edilson Delgado Trejos

2010-01-01

100

Endoreversible terrestrial solar energy conversion  

Microsoft Academic Search

The analysis of reversible radiation conversion is insightful in process optimization and provides the upper limit to performance of any conceptual device. However, in practice, irreversibilities are unavoidable and play an important role in performance optimization. The finite absorption of a radiative source flux, and the simultaneous emission of radiation, is an inherently irreversible process. Likewise, heat rejection from the

S. E. Wright

2008-01-01

101

Photochemical Conversion of Solar Energy.  

National Technical Information Service (NTIS)

Totally illuminated-multi thin layer (TI-MTL) iron-thiazine photogalvanic cells with SnO2 anodes and InSnO2 cathodes were constructed. A .07% sunlight engineering efficiency for power conversion was obtained with a 4-element TI-MTL iron-thionine cell with...

N. N. Lichtin

1976-01-01

102

NASA-OAST photovoltaic energy conversion program  

NASA Astrophysics Data System (ADS)

The NASA program in photovoltaic energy conversion research is discussed. Solar cells, solar arrays, gallium arsenides, space station and spacecraft power supplies, and state of the art devices are discussed.

Mullin, J. P.; Loria, J. C.

103

Figures of Merit for Energy Conversion Processes  

ERIC Educational Resources Information Center

Explores the problem of how to determine standards of performance for energy conversion processes. Argues against infinitely slow reversible processes as standards, and explores simple and faster alternative processes. (Author/GA)

Rubin, Morton H.

1978-01-01

104

Screening Method for Wind Energy Conversion Systems.  

National Technical Information Service (NTIS)

A screening method is presented for evaluating wind energy conversion systems (WECS) logically and consistently. It is a set of procedures supported by a data base for large conventional WECS. The procedures are flexible enough to accommodate concepts lac...

R. D. McConnell

1980-01-01

105

Chemistry of energy conversion and storage.  

PubMed

Energy is a big issue in our society, fueled by growing awareness of the finite resources of liquid fossil fuels and the noticeable changes in our climate resulting from its consumption. The general consensus is that there should be a well-considered roadmap towards a future energy scenario, with the replacement of fossil energy by renewable energies as the final goal. This "Chemistry of Energy Conversion and Storage" issue contains papers dealing with the chemistry behind renewable energies. PMID:22407997

Su, Dang Sheng

2012-03-08

106

Radioisotope Micropower System Using Thermophotovoltaic Energy Conversion  

NASA Astrophysics Data System (ADS)

Recent advances in thermophotovoltaic (TPV) energy conversion efficiency have increased interest in investigating the use of TPV in a wider spectrum of applications. This paper discusses a micropower system under development that utilizes a radioisotope heat source, microelectromechanical (MEM) thermal insulation, 3-D tungsten photonic crystal (PC) emitter, and thermophotovoltaic modules for the energy conversion. The 3-D tungsten photonic crystal (PC) emitter is a selective emitter that is designed to match the bandgap of the TPV module. Compared to bulk tungsten, the PC has increased emittance in the convertible wavelength range and decreased emittance in the nonconvertible wavelength range, which results in a greater than 10% improvement in conversion efficiency.

Koudelka, Robert D.; Murray, Christopher S.; Fleming, James G.; Shaw, Michael J.; Teofilo, Vince; Alexander, Charles

2006-01-01

107

Electrochemical Conversion of Light Energy Using Semiconductors.  

National Technical Information Service (NTIS)

In order to convert the light energy to the electrical and/or chemical energy, the photoelectrochemical properties of various semiconductors, such as SiC, GaAs, GaP, and polypyrrole, were investigated and applied to the novel light energy conversion syste...

T. Yamase T. Inoue

1984-01-01

108

Sea Energy Conversion: Problems and Possibilities  

Microsoft Academic Search

Nowadays, policies are being developed in many countries in order to decrease their greenhouse gases emissions. While in this area some technologies are widely installed (wind and solar energy), other ones, like the sea energy, could get an important role in the medium and long term. That is why the most relevant technologies associated to the sea energy conversion are

G. Buigues; I. Zamora; A. J. Mazón; V. Valverde; F. J. Pérez

109

Bio-Inspired Solar Energy Conversion  

Microsoft Academic Search

The areas of solar-powered catalysts for energy rich fuels formation and bio-inspired molecular assemblies for integrating photon-to-fuels pathways have been identified by the Office of Basic Energy Sciences of the U. S. Department of Energy as challenges for the next generation of sustainable, high-efficiency solar energy conversion systems [1]. The light-harvesting, energy-transducing and carbon compound-synthesizing (carbon dioxide-fixing) reactions that are

Kurt Warncke

2009-01-01

110

Energy transfer processes in solar energy conversion  

SciTech Connect

This program involves the experimental and theoretical study of optically induced electron transfer and electronic excitation transport in systems with complex structures. The focus is to obtain an understanding of the intimate interplay among intermolecular interactions, structure, and dynamics. A combination of picosecond transient grating experiments, time resolved fluorescence depolarization experiments, conventional optical spectroscopy, and statistical mechanical theory is being employed to elucidated fundamental aspects of processes which are important in the conversion of solar energy to usable forms of energy. We are continuing to address the very important problem of electron back transfer following optically induced donor to acceptor electron transfer. In a system in which there are donors (low concentration) and acceptors (high concentration) randomly distributed in solution, optical excitation of a donor can be followed by transfer of an electron to an acceptor. One electron transfer has occurred. there exists a ground state radical cation (D{sup +}) near a ground state radical anion (A{sup {minus}}). Since the thermodynamically stable state is neutral ground state D and A, back transfer will occur. The electron will back transfer from A{sup {minus}} to D{sup +} to regenerate the neutral species. In liquid solution, back transfer competes with separation by diffusion. Separated ions are extremely reactive and can go on to do useful chemistry. 10 refs.

Fayer, M.D.

1987-01-01

111

Direct energy conversion of radiation energy in fusion reactor.  

National Technical Information Service (NTIS)

Direct energy conversion from plasma heat flux has been studied. Since major parts of fusion energy in the advanced fusion reactor are radiation and charged particle energies, the flexible design of the blanket is possible. We discuss the potentiality of ...

S. Yamaguchi A. Iiyoshi O. Motojima M. Okamoto S. Sudo

1993-01-01

112

Biomass energy conversion as an alternate energy source  

Microsoft Academic Search

A study in the US indicates that 327 t or 44% of the biomass produced in the US other than agricultural and forestry products would be available for conversion into energy but would yield only 1.9% of the total energy currently used annually. The major advantages and disadvantages of using biomass material for energy conversion are given. Food processing wastes,

N. Goodman; D. Pimentel

2009-01-01

113

Direct Energy Conversion, a current awareness bulletin  

NASA Astrophysics Data System (ADS)

This bulletin contains 94 abstracts and bibliographic citations of scientific and technical reports, journal articles, conference proceedings, patents, books, and other published literature on all aspects of direct energy conversion. A subject index and a report number index are provided. This information is selected from the DOE/TIC Energy Data Base.

1982-08-01

114

Iron disulfide for solar energy conversion  

Microsoft Academic Search

Pyrite (Eg = 0.95 eV) is being developed as a solar energy material due to its environmental compatibility and its very high light absorption coefficient. A compilation of material, electronic and interfacial chemical properties is presented, which is considered relevant for quantum energy conversion. In spite of intricate problems existing within material chemistry, high quantum efficiencies for photocurrent generation (Eta

A ENNAOUI; S FIECHTER; C PETTENKOFER; N ALONSOVANTE; K BUKER; M BRONOLD; C HOPFNER; H TRIBUTSCH

1993-01-01

115

Nonconventional alternatives for conversion of nuclear energy  

Microsoft Academic Search

Various systems for converting the energy of nuclear fission fragments into different forms of electromagnetic energy are discussed. Special attention is devoted to direct conversion cells, and a simple theoretical model is developed for the self-excitation of the anode voltage in a cell with grid at either positive or negative voltage. Theoretical predictions of anode voltages are compared with experimental

I. Ursu; I. I. Purica; A. I. Badescu-Singureanu

1978-01-01

116

Ocean thermal energy conversion: Perspective and status  

Microsoft Academic Search

The use of the thermal gradient between the warm surface waters and the deep cold waters of tropical oceans was first proposed by J. A. d'Arsonval in 1881 and tried unsuccessfully by George Claude in 1930. Interest in Ocean Thermal Energy Conversion (OTEC) and other renewable energy sources revived in the 1970s as a result of oil embargoes. At that

Anthony Thomas; David L. Hillis

1990-01-01

117

Energy Forms, States and Conversions  

NSDL National Science Digital Library

Students participate in many demonstrations during the first day of this lesson to learn basic concepts related to the forms and states of energy. This knowledge is then applied the second day as students assess various everyday objects to determine what forms of energy are transformed to accomplish the object's intended task. Students use block diagrams to illustrate the form and state of energy flowing into and out of the process.

Office Of Educational Partnerships

118

Solar energy conversion through photosynthesis  

Microsoft Academic Search

Energy sources of possible quantitative significance which are directly or indirectly of contemporary solar origin are considered, taking into account wind-powered electric generators, ocean thermal gradients, direct solar heating, variations of agriculture, photosynthetic hydrogen production, and photoelectric devices. The most practical schemes for capturing solar energy appear at this time to be directly heating and harnessing the wind. Silicon photovoltaic

R. K. Clayton

1977-01-01

119

Speed, Acceleration, and Velocity: Level II, Unit 9, Lesson 1; Force, Mass, and Distance: Lesson 2; Types of Motion and Rest: Lesson 3; Electricity and Magnetism: Lesson 4; Electrical, Magnetic, and Gravitational Fields: Lesson 5; The Conservation and Conversion of Matter and Energy: Lesson 6; Simple Machines and Work: Lesson 7; Gas Laws: Lesson 8; Principles of Heat Engines: Lesson 9; Sound and Sound Waves: Lesson 10; Light Waves and Particles: Lesson 11; Program. A High.....  

ERIC Educational Resources Information Center

This self-study program for high-school level contains lessons on: Speed, Acceleration, and Velocity; Force, Mass, and Distance; Types of Motion and Rest; Electricity and Magnetism; Electrical, Magnetic, and Gravitational Fields; The Conservation and Conversion of Matter and Energy; Simple Machines and Work; Gas Laws; Principles of Heat Engines;…

Manpower Administration (DOL), Washington, DC. Job Corps.

120

Speed, Acceleration, and Velocity: Level II, Unit 9, Lesson 1; Force, Mass, and Distance: Lesson 2; Types of Motion and Rest: Lesson 3; Electricity and Magnetism: Lesson 4; Electrical, Magnetic, and Gravitational Fields: Lesson 5; The Conservation and Conversion of Matter and Energy: Lesson 6; Simple Machines and Work: Lesson 7; Gas Laws: Lesson 8; Principles of Heat Engines: Lesson 9; Sound and Sound Waves: Lesson 10; Light Waves and Particles: Lesson 11; Program. A High.....  

ERIC Educational Resources Information Center

|This self-study program for high-school level contains lessons on: Speed, Acceleration, and Velocity; Force, Mass, and Distance; Types of Motion and Rest; Electricity and Magnetism; Electrical, Magnetic, and Gravitational Fields; The Conservation and Conversion of Matter and Energy; Simple Machines and Work; Gas Laws; Principles of Heat Engines;…

Manpower Administration (DOL), Washington, DC. Job Corps.

121

Energy conversion in natural and artificial photosynthesis.  

PubMed

Modern civilization is dependent upon fossil fuels, a nonrenewable energy source originally provided by the storage of solar energy. Fossil-fuel dependence has severe consequences, including energy security issues and greenhouse gas emissions. The consequences of fossil-fuel dependence could be avoided by fuel-producing artificial systems that mimic natural photosynthesis, directly converting solar energy to fuel. This review describes the three key components of solar energy conversion in photosynthesis: light harvesting, charge separation, and catalysis. These processes are compared in natural and in artificial systems. Such a comparison can assist in understanding the general principles of photosynthesis and in developing working devices, including photoelectrochemical cells, for solar energy conversion. PMID:20534342

McConnell, Iain; Li, Gonghu; Brudvig, Gary W

2010-05-28

122

Silicon nanowires for photovoltaic solar energy conversion.  

PubMed

Semiconductor nanowires are attracting intense interest as a promising material for solar energy conversion for the new-generation photovoltaic (PV) technology. In particular, silicon nanowires (SiNWs) are under active investigation for PV applications because they offer novel approaches for solar-to-electric energy conversion leading to high-efficiency devices via simple manufacturing. This article reviews the recent developments in the utilization of SiNWs for PV applications, the relationship between SiNW-based PV device structure and performance, and the challenges to obtaining high-performance cost-effective solar cells. PMID:20931630

Peng, Kui-Qing; Lee, Shuit-Tong

2011-01-11

123

Energy Conversion in a CW Laser Thruster  

NASA Astrophysics Data System (ADS)

An experimental study on the energy conversion process of a continuous wave (CW) laser thruster is presented. The effect of the flow parameters on two dominant loss mechanisms of a CW laser thruster was investigated by using a CW CO2 laser with output power of 700W. The laser transmission and radiation from the laser sustained-plasma (LSP) were measured for several flow velocities and pressures, which were independently controlled. CCD camera was employed in order to observe the shape and position of the LSPs. We found that the energy conversion process is optimized when the LSP is in the vicinity of the focal point of the condensing laser beam.

Inoue, Takayoshi; Uehara, Susumu; Komurasaki, Kimiya; Arakawa, Yoshihiro

124

US energy conversion and use characteristics  

SciTech Connect

The long-range goal of the Energy Conversion and Utilization Technology (ECUT) Program is to enhance energy productivity in all energy-use sectors by supporting research on improved efficiency and fuel switching capability in the conversion and utilization of energy. Regardless of the deficiencies of current information, a summary of the best available energy-use information is needed now to support current ECUT program planning. This document is the initial draft of this type of summary and serves as a data book that will present current and periodically updated descriptions of the following aspects of energy use: gross US energy consumption in each major energy-use sector; energy consumption by fuel type in each sector; energy efficiency of major equipment/processes; and inventories, replacement rates, and use patterns for major energy-using capital stocks. These data will help the ECUT program staff perform two vital planning functions: determine areas in which research to improve energy productivity might provide significant energy savings or fuel switching and estimate the actual effect that specific research projects may have on energy productivity and conservation. Descriptions of the data sources and examples of the uses of the different types of data are provided in Section 2. The energy-use information is presented in the last four sections; Section 3 contains general, national consumption data; and Sections 4 through 6 contain residential/commercial, industrial, and transportation consumption data, respectively. (MCW)

Imhoff, C.H.; Liberman, A.; Ashton, W.B.

1982-02-01

125

COORDINATION AS ENERGY-IN- CONVERSATION  

Microsoft Academic Search

Coordination is the process people use to create, adapt, and re-create organizations. We propose a theory of coordination as energy-in-conversation to help organizational scholars comprehend the emotional and motivational dynamics of coordination. Our model describes how people generate and diminish their energy in their attempts to coordinate, how this energy affects attempts to coordinate, and how coordinating affects the effort

RYAN W. QUINN; JANE E. DUTTON

2005-01-01

126

A program for magnetic susceptibility-equivalent pore conversion  

NASA Astrophysics Data System (ADS)

Pore magnetic anisotropy can be used to estimate the average geometry of void spaces in rocks in the form of the equivalent pore (EP) ellipsoid. Direct computation of EP from measured magnetic susceptibility is impossible. We present a method and a Matlab program for automatic magnetic susceptibility-equivalent pore conversion. Input data are the magnetic parameters (P and T, or L and F) representing the bulk magnetic anisotropy, and the intrinsic susceptibility of the fluid used in the measurement. EP is estimated iteratively by a repeated look-up table procedure using P and T values computed in a coarse grid of EP axial ratios. The program may be downloaded from the EarthRef.org Digital Archive.

Jezek, J.; Hrouda, F.

2007-10-01

127

Lightning energy conversion using lasers  

Microsoft Academic Search

Potential energy sources are being investigated for the socioeconomic needs and increased power demand. Systems employing nuclear, thermal, hydro, solar, volcano, MHD, tidal and wind power generation techniques already exist. This work describes our attempt to utilize the off-planet lightning charge to store super electrolytic batteries or super capacitors. The electrostatic charge on clouds can be shifted to earth through

Nasrullah Khan; Norman Mariun

2000-01-01

128

Energy Conversion: Nano Solar Cell  

NASA Astrophysics Data System (ADS)

Problems of fossil-fuel-induced climate change have sparked a demand for sustainable energy supply for all sectors of economy. Most laboratories continue to search for new materials and new technique to generate clean energy at affordable cost. Nanotechnology can play a major role in solving the energy problem. The prospect for solar energy using Si-based technology is not encouraging. Si photovoltaics can produce electricity at 20-30 cslash/kWhr with about 25% efficiency. Nanoparticles have a strong capacity to absorb light and generate more electrons for current as discovered in the recent work of organic and dye-sensitized cell. Using cheap preparation technique such as screen-printing and self-assembly growth, organic cells shows a strong potential for commercialization. Thin Films research group at National University Malaysia has been actively involved in these areas, and in this seminar, we will present a review works on nanomaterials for solar cells and particularly on hybrid organic solar cell based on ZnO nanorod arrays. The organic layer consisting of poly[2-methoxy-5-(2-ethylhexyloxy)-1, 4-phenylenevinylene] (MEHPPV) and [6, 6]-phenyl C61-butyric acid 3-ethylthiophene ester (PCBE) was spin-coated on ZnO nanorod arrays. ZnO nanorod arrays were grown on FTO glass substrates which were pre-coated with ZnO nanoparticles using a low temperature chemical solution method. A gold electrode was used as the top contact. The device gave a short circuit current density of 2.49×10-4 mA/cm2 and an open circuit voltage of 0.45 V under illumination of a projector halogen light at 100 mW/cm2.

Yahaya, Muhammad; Yap, Chi Chin; Mat Salleh, Muhamad

2009-09-01

129

Nanostructured materials for solar energy conversion  

Microsoft Academic Search

This review article deals with the motivation for using nanostructured materials in the field of solar energy conversion. We discuss briefly some recent fundamental observations on supported nanoclusters and optical properties of embedded metallic nanoclusters in a dielectric matrix. An overview on current research and existing applications in this field is given. Nanocomposite thin films developed for the application as

P. Oelhafen; A. Schüler

2005-01-01

130

Efficiency of energy conversion in Nitinol  

Microsoft Academic Search

The efficiency of the energy conversion in Nitinol was investigated experimentally. An electronically controlled Cycle Simulator subjected a single Nitinol wire element to the stress strain temperature cycles corresponding to a specific thermodynamic cycle. The test parameters, which were varied singly or in combination, included various stress levels, stress rates, percent of elongation of the wire, temperature levels, heating and

R. D. Kopa

1979-01-01

131

Direct conversion of muon catalyzed fusion energy.  

National Technical Information Service (NTIS)

In this paper a method of direct conversion of muon catalyzed fusion (MCF) energy is proposed in order to reduce the cost of muon production. This MCF concept is based on a pellet composed of many thin solid deuterium-tritium (DT) rods encircled by a meta...

T. Tajima S. Eliezer R. M. Kulsrud

1990-01-01

132

Numerical simulation of direct energy conversion  

Microsoft Academic Search

Use of numerical simulation to study Post's (1970) electrostatic scheme for direct conversion of fusion energy to electricity. Using a two-dimensional electrostatic approach, it is shown that useful efficiency information may be obtained from monoenergetic low-density (ratio of ion number density to critical density much less than 1) ion beams. Using the generated efficiency function, it is possible to find

S. J. Gitomer; C. K. Krishnan

1974-01-01

133

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

134

Interfacial systems for photochemical energy conversion  

NASA Astrophysics Data System (ADS)

Research supported by the DOE falls in the areas of: (1) multicomponent redox molecules; (2) polymer-modified electrodes and semiconductor photoelectrodes; (3) semiconductor surface chemistry; and (4) multielectron transfer biological catalysts for redox energy conversion processes. Highlights of research in these areas are given. Plans for the concluding year of the grant are also summarized.

Wrighton, Mark S.

135

Ocean thermal energy conversion: Perspective and status.  

National Technical Information Service (NTIS)

The use of the thermal gradient between the warm surface waters and the deep cold waters of tropical oceans was first proposed by J. A. d'Arsonval in 1881 and tried unsuccessfully be George Claude in 1930. Interest in Ocean Thermal Energy Conversion (OTEC...

A. Thomas D. L. Hillis

1990-01-01

136

Modernization of Biomass Energy Conversion Facilities  

Microsoft Academic Search

In this paper, the modernization studies of biomass energy conversion facilities are briefly reviewed. Here, the term biomass includes organic matter produced as a result of photosynthesis as well as municipal, industrial and animal waste material. The term modern biomass is generally used to describe the traditional biomass use through the efficient and clean combustion technologies and sustained supply of

A. Demirbas

2007-01-01

137

Thermal to electricity conversion using thermal magnetic properties  

DOEpatents

A system for the generation of Electricity from Thermal Energy using the thermal magnetic properties of a Ferromagnetic, Electrically Conductive Material (FECM) in one or more Magnetic Fields. A FECM is exposed to one or more Magnetic Fields. Thermal Energy is applied to a portion of the FECM heating the FECM above its Curie Point. The FECM, now partially paramagnetic, moves under the force of the one or more Magnetic Fields. The movement of the FECM induces an electrical current through the FECM, generating Electricity.

West, Phillip B [Idaho Falls, ID; Svoboda, John [Idaho Falls, ID

2010-04-27

138

An efficient experimental method for high power direct drive wind energy conversion systems  

Microsoft Academic Search

Because of energy shortage and environment pollution, the renewable energy, especially wind energy has become more and more considerable all over the world. Direct drive wind energy conversion systems based on multipole permanent magnet synchronous generator (PMSG) have some advantages such as no gearbox, high power density, high precision and easy to control. In our research project, a 2MW direct

Weihao Hu; Yue Wang; Weizheng Yao; Jinlong Wu; Hailong Zhang; Zhaoan Wang

2008-01-01

139

Conversion of radiant light energy in photobioreactors  

SciTech Connect

The conversion of radiant light energy into chemical affinity by microorganisms in photobioreactors is examined. The kinetics of entropy production in the system is theoretically established from entropy and energy balances for the material and photonic phases in the reactor. A negative chemical affinity term compensated for by a radiant energy term at a higher level of energy characterizes photosynthetic organisms. The local volumetric rate of radiant light energy absorbed, which appears in the dissipation function as an irreversible term, is calculated for monodimensional approximations providing analytical solutions and for general tridimensional equations requiring the solution of a new numerical algorithm. Solutions for the blue-green alga Spirulina platensis cultivated in photoreactors with different geometries and light energy inputs are compared. Thermodynamic efficiency of the photosynthesis is calculated. The highest value of 15% found for low radiant energy absorption rates corresponds to a maximum quantum yield in the reactor.

Cornet, J.F.; Dussap, C.G.; Gros, J.B. (Univ. Blase Pascal, Aubiere (France). Lab. de Genie Chimique Biologique)

1994-06-01

140

Apparatus for testing direct energy conversion of plasma energy to electricity  

Microsoft Academic Search

The Lawrence Livermore Laboratory program for research and development ; of direct energy conversion for fusion reactor application is described. A new ; test facility consisting of a system of magnets, a vacuum chamber, and collector ; structure of unusual shapes and sizes is described. Under laboratory conditions, ; the anticipated collection efficiencies are 65% for a 2-stage venetian blind

W. L. Barr; M. O. Calderon; T. N. Haratani; J. D. Kinney; R. W. Moir; R. R. Smith

1973-01-01

141

Thermoelectric energy conversion with solid electrolytes  

Microsoft Academic Search

The alkali metal thermoelectric converter (AMTEC) is a device for the direct conversion of heat to electrical energy. The sodium ion conductor beta-double prime-alumina is used to form a high-temperature regenerative concentration cell for elemental sodium. An AMTEC of mature design should have an efficiency of 20 to 40 percent, a power density of 0.5 kilowatt per kilogram or more,

T. Cole

1983-01-01

142

Solar thermochemical energy conversion and transport  

Microsoft Academic Search

The high temperature catalytic dissociation of SO3 and the CO2-CH4 reforming-methanation cycle are important chemical processes being considered in the development and application of solar-thermal energy conversion, transport, and storage systems. Separate facilities for evaluating chemical converter-heat exchangers at temperatures to 1000 C with high flow rates of SO3 and of mixtures of CO2 and CH4 feedstocks have been assembled

J. H. McCrary; G. E. McCrary

1982-01-01

143

Test Program for Wind Energy Conversion System Growian.  

National Technical Information Service (NTIS)

The planned test program for wind energy conversion is described. Measurements made of wind distribution, efficiency of energy conversion, dynamic effects, electric behavior, optimization of control, and environmental impact, like sound and TV interferenc...

F. Koerber

1982-01-01

144

Linear mode conversion of Langmuir/z-mode waves to radiation: Scalings of conversion efficiencies and propagation angles with temperature and magnetic field orientation  

NASA Astrophysics Data System (ADS)

Linear mode conversion (LMC) is the linear transfer of energy from one wave mode to another in an inhomogeneous plasma. It is relevant to laboratory plasmas and multiple solar system radio emissions, such as continuum radiation from planetary magnetospheres and type II and III radio bursts from the solar corona and solar wind. This paper simulates LMC of waves defined by warm, magnetized fluid theory, specifically the conversion of Langmuir/z-mode waves to electromagnetic (EM) radiation. The primary focus is the calculation of the energy and power conversion efficiencies for LMC as functions of the angle of incidence ? of the Langmuir/z-mode wave, temperature ?=Te/mec2, adiabatic index ?, and orientation angle ? between the ambient density gradient ?N0 and ambient magnetic field B0 in a warm, unmagnetized plasma. The ratio of these efficiencies is found to agree well as a function of ?, ?, and ? with an analytical relation that depends on the group speeds of the Langmuir/z and EM wave modes. The results demonstrate that the energy conversion efficiency ? is strongly dependent on ??, ? and ?, with ?~(??)1/2 and ?~(??)1/2. The power conversion efficiency ?p, on the other hand, is independent of ?? but does vary significantly with ? and ?. The efficiencies are shown to be maximum for approximately perpendicular density gradients (?~90°) and minimal for parallel orientation (?=0°) and both the energy and power conversion efficiencies peak at the same ?.

Schleyer, F.; Cairns, Iver H.; Kim, E.-H.

2013-03-01

145

Magnet energy storage  

SciTech Connect

The paper gives a brief review of magnet energy storage (MES) development in the USSR and outlines the status in the following areas: supporting theoretical studies, commutation equipment, superconducting materials, development of conventional, cryoresistive and superconducting MES.

Akopyan, D.G.; Batakov, Y.P.; Dedjurin, A.M.; Druzhinin, A.S.; Egorov, S.A.; Zapretilina, E.R.; Kostenko, A.I.; Kuchinsky, V.G.; Larionov, B.A.; Monoszon, N.A. (D.V. Efremov Scientific Research Inst. of Electrophysical Apparatus, Leningrad (SU))

1992-01-01

146

Promising applications of the liquid metal MHD energy conversion technology  

Microsoft Academic Search

Applications of the liquid-metal MHD (magnetohydrodynamic) energy conversion technology that could benefit from its unique features are reviewed with emphasis on applications that might be realized in the relatively near future and on the OMACON (optimized magnetohydrodynamic conversion) concept. Included among the promising applications are cogeneration, energy recovery from industrial processes involving the use of molten metals, energy conversion from

H. Branover; A. El-Boher; E. Greenspan; A. Barak

1989-01-01

147

Energy from vegetation: legal issues in biomass energy conversion  

Microsoft Academic Search

The major legal and institutional issues to be considered as biomass energy technologies are developed and discussed in terms of the phases in the production of energy from biomass: collection and production, conversion to direct energy souces, and products and delivery systems. Attention is focused on forestry and agricultural residues and wastes and on terrestrial fuel farms. (MHR)

Schwab

1979-01-01

148

Oriented Nanostructures for Energy Conversion and Storage  

SciTech Connect

Recently the role of nanostructured materials in addressing the challenges in energy and natural resources has attracted wide attention. In particular, oriented nanostructures have demonstrated promising properties for energy harvesting, conversion and storage. The purpose of the paper is to review the synthesis and application of oriented nanostructures in a few key areas of energy technologies, namely photovoltaics, batteries, supercapacitors and thermoelectrics. Although the applications differ from field to field, one of the fundamental challenges is to improve the generation and transport of electrons and ions. We will first briefly review the several major approaches to attain oriented nanostructured films that are applicable for energy applications. We will then discuss how such controlled nanostructures can be used in photovoltaics, batteries, capacitors, thermoelectrics, and other unconventional ways of energy conversion. We will highlight the role of high surface area to maximize the surface activity, and the importance of optimum dimension and architecture, controlled pore channels and alignment of the nanocrystalline phase to optimize the electrons and ion transport. Finally, the paper will discuss the challenges in attaining integrated architectures to achieve the desired performance. Brief background information will be provided for the relevant technologies, but the emphasis is focused mainly on the nanoeffects of mostly inorganic based materials and devices.

Liu, Jun; Cao, Guozhong H.; Yang, Zhenguo; Wang, Donghai; DuBois, Daniel L.; Zhou, Xiao Dong; Graff, Gordon L.; Pederson, Larry R.; Zhang, Jiguang

2008-08-28

149

Preliminary studies of direct energy conversion in a D- sup 3 He fusion reactor  

Microsoft Academic Search

In this paper, a direct energy conversion method is proposed for a D-³He inertial confinement fusion reactor. The method utilizes inductive energy recovery through pickup coils in the plasma chamber in which mirror magnetic fields are applied. A method to reduce the problems regarding the handling of ultrahigh voltage inherent in energy recovery of this type is proposed that divides

K. Mima; H. Takabe; Y. Kitagawa; S. Nakai; K. Yoshikawa; O. Morimaya; H. Takase; T. Tajima; Y. Kosaki

1992-01-01

150

System Performance Projections for TPV Energy Conversion  

SciTech Connect

TPV technology has advanced rapidly in the last five years, with diode conversion efficiency approaching >30%, and filter efficiency of {approx}80%. These achievements have enabled repeatable testing of 20% efficient small systems, demonstrating the potential of TPV energy conversion. Near term technology gains support a 25% efficient technology demonstration in the two year timeframe. However, testing of full size systems, which includes efficiency degradation mechanisms, such as: nonuniform diode illumination, diode and filter variability, temperature non-uniformities, conduction/convection losses, and lifetime reliability processes needs to be performed. A preliminary analysis of these differential effects has been completed, and indicates a near term integrated system efficiency of {approx}15% is possible using current technology, with long term growth to 18-20%. This report addresses the system performance issues.

PF Baldasaro; MW Dashiell; JE Oppenlander; JL Vell; P Fourspring; K Rahner; LR Danielson; S Burger; E Brown

2004-06-09

151

Ocean thermal energy conversion: Materials issues  

NASA Astrophysics Data System (ADS)

The Ocean thermal Energy Conversion (OTEC) Program, in the Ocean Energy Technology Division of the U.S. Department of Energy, is concerned with the development of options that can be utilized to extract and distribute significant amounts of energy from the ocean. The biofouling control and materials portion of the program is concerned with the development of effective and environmentally acceptable methods to minimize biofouling and corrosion in high thermal conductivity materials suitable for use in heat exchangers and condensers. The mechanical and chemical techniques employed for biofouling control are reviewed and the recent success with chlorination is presented. The corrosion of aluminum alloys, copper alloys, stainless steel, stainless alloys, and titanium in near-surface warm and deep cold water is reviewed with emphasis on aluminum alloys. The major materials issues are reviewed with emphasis on lifetime and cost.

Darby, J. B., Jr.

152

Ocean energy conversion systems annual research report  

SciTech Connect

Alternative power cycle concepts to the closed-cycle Rankine are evaluated and those that show potential for delivering power in a cost-effective and environmentally acceptable fashion are explored. Concepts are classified according to the ocean energy resource: thermal, waves, currents, and salinity gradient. Research projects have been funded and reported in each of these areas. The lift of seawater entrained in a vertical steam flow can provide potential energy for a conventional hydraulic turbine conversion system. Quantification of the process and assessment of potential costs must be completed to support concept evaluation. Exploratory development is being completed in thermoelectricity and 2-phase nozzles for other thermal concepts. Wave energy concepts are being evaluated by analysis and model testing with present emphasis on pneumatic turbines and wave focussing. Likewise, several conversion approaches to ocean current energy are being evaluated. The use of salinity resources requires further research in membranes or the development of membraneless processes. Using the thermal resource in a Claude cycle process as a power converter is promising, and a program of R and D and subsystem development has been initiated to provide confirmation of the preliminary conclusion.

Not Available

1981-03-01

153

Modern energy conversion systems and nuclear energy  

Microsoft Academic Search

The search for improving the heat rate of the fossil thermal power systems is being pursued and even amplified. For the most part, nuclear energy is kept apart from this worldwide trend. The net efficiency of common light water reactor plants is as low as 33%. It cannot be increased because of temperature limitations. For the next few decades, it

Tilliette

1993-01-01

154

Wind energy conversion: is it environmentally acceptable  

SciTech Connect

An overview of the current status of the knowledge regarding potential environmental impediments to the commercialization of Wind Energy Conversion System (WECS) is presented. The text also identifies pertinent studies conducted in each area and summarizes the conclusions of the studies. In rough order of importance, the identified environmental impediments to the widespread use of WECS are as follows: electromagnetic interference; land use; aesthetics visual pollution; noise; and biophysical effects. Assessment of the environmental impacts of wind energy conversion system as they reflect to the five generic areas investigated is summarized. The results indicate that of the five generic areas, only the television video signal interference and specific very local impacts related to land use and aesthetics are nonnegligible factors. The severity of the television interference problem has been well studied and verified analytical relationships have been established for determining the extent of the interference zone, which in even the worst case is limited to 4 to 6 km (2 or 3 miles) from a WECS with a rotor diameter of 38 m (125 ft). Fringe reception areas, where the worst interference is encountered, generally have access to cable television, which eliminates the problem. With smaller rotor diameters, the problem should be negligible and additional investigations are currently underway to verify this hypothesis. The potential problems relating to land use and aesthetics are site-specific and depending on the nature of the problem may be relatively hard to resolve. However, it can be concluded in general there appear to be no insurmountable environmental constraints on the general widespread use of wind energy conversion systems.

Cingo, R.P.

1980-11-01

155

On conversion between potential and kinetic energy in the atmosphere  

Microsoft Academic Search

Summary The mechanism of conversion between potential and kinetic energy in different parts of the Northern Hemisphere is discussed. In low latitudes, between the Equator and 30° N, a large part of the total energy conversion occurs in connection with a mean meridional circulation, the «Hadley circulation». In this the rate of conversion amounts to about 35×1010 kilojoules per second

E. Palmén

1961-01-01

156

Energy conversion efficiencies of thermoelectric pallets (Bi2Pb3,Bi2Te3 and Pb2Te3) under the influences of electric and magnetic fields  

NASA Astrophysics Data System (ADS)

This paper aims to introduce the ability of thermo electric pallets to convert waste heat into electricity and also about the effect of electric or magnetic fields, which can exist already or applied in the conditions of their operation. Three thermo electric pallets (Bi2Pb3,Bi2Te3 and Pb2Te3) of cylindrical dimensions are prepared by 15mm mixture of different compositions. Thermo emf generations are carried out in the normal mode and then under the influence of applied electric and magnetic fields of different magnitudes in the temperature range of 460K.

Singh, Jaspal; Verma, S. S.

2013-06-01

157

DIRECT CONVERSION OF NUCLEAR ENERGY INTO ELECTRICAL OR THRUST ENERGY  

Microsoft Academic Search

Direct conversion of nuclear energy into electrical energy or thrust ; involves the confinement of a plasma at temperatures of the order of 10⁸ ; deg K and higher, which excludes physical walls. Two concepts through which this ; may be done are introduced. In both cases spherical waves propagate radially ; inward. In the first, the amplitude is the

Fuechsel

1962-01-01

158

Energy and reliability benefits of wind energy conversion systems  

Microsoft Academic Search

The electrical energy production and reliability benefits of a wind energy conversion system (WECS) at a specific site depend on many factors, including the statistical characteristics of the site wind speed and the design characteristics of the wind turbine generator (WTG) itself, particularly the cut-in, rated and cut-out wind speed parameters. In general, the higher the degree of the wind

Kaigui Xie; Roy Billinton

2011-01-01

159

Energy transfer processes in solar energy conversion  

SciTech Connect

We have made substantial progress in experimental and theoretical studies in two areas: Photoinduced donor to acceptor electron transfer followed by back transfer in random solutions; and electronic excitation transport in systems with complex inhomogeneous spatial geometries and inhomogeneous energy distributions. Through the development of accurate statistical mechanical theories, we have been able to relate dynamics in complex systems to experimental observables. We have then used the experimental observables, time resolved fluorescence depolarization and transient grating experiments, to examine well defined molecular systems. The agreement between theory and experiment is excellent. 11 refs.

Fayer, M.D.

1989-11-01

160

Energy transfer processes in solar energy conversion  

SciTech Connect

By combining picosecond optical experiments and detailed statistical mechanics theory we continue to increase our understanding of the complex interplay of structure and dynamics in important energy transfer situations. A number of different types of problems will be focused on experimentally and theoretically. They are excitation transport among chromophores attached to finite size polymer coils; excitation transport among chromophores in monolayers, bilayers, and finite and infinite stacks of layers; excitation transport in large vesicle systems; and photoinduced electron transfer in glasses and liquids, focusing particularly on the back transfer of the electron from the photogenerated radical anion to the radical cation. 33 refs., 13 figs.

Fayer, M.D.

1986-11-01

161

Loss analysis of the thermodynamic cycle of magnetic heat pumps. Phase 1, Final report of thermal sciences research program on thermophysics of magnetocaloric energy conversion.  

National Technical Information Service (NTIS)

The needs for developing non-ozone-depleting, no-greenhouse-effect heat pump systems and for exploring the potential of new high-temperature superconducting materials have prompted a renewed interest in the study of magnetic heat pumps. The new materials ...

F. C. Chen R. W. Murphy V. C. Mei G. L. Chen J. W. Lue

1991-01-01

162

Performance evaluation of grid connected wind energy conversion systems with five-phase modular permanent magnet synchronous generators having different slot and pole number combinations  

Microsoft Academic Search

The performance of modular permanent magnet machines depends on proper selection of the pole and slot numbers which results in negligible coupling between phases. Preferred slot and pole number combinations eliminate the effect of low order harmonics in the stator MMF, thereby reducing vibration and stray loss. In this paper, three machines, with identical dimensions, are designed with different slots

Ayman S. Abdel-Khalik; Khaled H. Ahmed

2011-01-01

163

Thermophotovoltaic energy conversion: Technology and market potential  

NASA Astrophysics Data System (ADS)

This report contains material displayed on poster panels during the Conference. The purpose of the contribution was to present a summary of the business overview of thermophotovoltaic generation of electricity and its market potential. The market analysis has shown that the TPV market, while currently still in an early nucleation phase, is evolving into a range of small niche markets out of which larger-size opportunities can emerge. Early commercial applications on yachts and recreational vehicles which require a quiet and emission-free compact electrical generator fit the current TPV technology and economics. Follow-on residential applications are attractive since they can combine generation of electricity with space and hot water heating in a co-generation system. Development of future markets in transportation, both private and communal or industrial, will be driven by legislation requiring emission-free vehicles, and by a reduction in TPV systems cost. As a result of ``moving down the learning curve,'' growing power and consumer markets are predicted to come into reach of TPV systems, a development favored by high overall energy conversion efficiency due to high radiation energy density and to high electric conversion efficiency available with photovoltaic cells.

Ostrowski, Leon J.; Pernisz, Udo C.; Fraas, Lewis M.

1996-02-01

164

Recycling of Wasted Energy: Thermal to Electrical Energy Conversion  

NASA Astrophysics Data System (ADS)

Harvesting useful electric energy from ambient thermal gradients and/or temperature fluctuations is immensely important. For many years, a number of direct and indirect thermal-to-electrical energy conversion technologies have been developed. Typically, direct energy conversion is achieved by using thermoelectric generators or thermogalvanic cells; indirect energy conversion is achieved by using Organic Rankine Cycle or Sterling Engines. On the one hand, there is a fundamental technical difficulty, thermal shorting, that limits the energy conversion efficiency of direct thermoelectric energy conversion methods. While extensive study has been conducted in this area, currently the portion of thermal energy that can be converted to electricity is still small. On the other hand, the indirect energy conversion systems tend to be complicated and expensive. Thus, existing energy harvesting technologies are less economically competitive compared with the grid power. To develop advanced energy harvesting systems, a novel concept using nanoporous materials is investigated. Nanoporous materials have been widely used as advanced absorbents. Because of their ultra-large surface areas (100--2000 m2/g), they can adsorb a large amount of ions when they are immersed in electrolyte solutions. The ion adsorption capacity is thermally dependent. If two nanoporous electrodes are placed at different temperatures, they adsorb different amounts of ions, generating a net output voltage. The thermally driven ion motion causes a transient current, which can be reactivated through temperature fluctuation or internal grounding. The two electrodes are isolated; that is, the direct heat loss between them is minimized. Our experimental data have shown encouraging results: the output voltage and the energy conversion efficiency are higher than that of conventional thermoelectric materials by orders of magnitude. Our study will not only lead to the development of high-performance thermal energy harvesting systems, but also shed light on fundamentals of electrophysics in nanoenvironment. The thermal effect on surface electrification (i.e. the capacitive effect) in nanopores is a new scientific area. Conventional interface theories have failed in explaining a number of experimental observations. We have carried out a systematic study of the effects of ions, solvent, electrode, cell configuration, etc. to understand the fundamental mechanisms and processes that govern the ion motion and charge transfer in nanopores.

Lim, Hyuck

165

Soft Magnetic Materials for Improved Energy Performance  

NASA Astrophysics Data System (ADS)

A main focus of sustainable energy research has been development of renewable energy technologies (e.g. from wind, solar, hydro, geothermal, etc.) to decrease our dependence on non-renewable energy resources (e.g. fossil fuels). By focusing on renewable energy sources now, we hope to provide enough energy resources for future generations. In parallel with this focus, it is essential to develop technologies that improve the efficiency of energy production, distribution, and consumption, to get the most from these renewable resources. Soft magnetic materials play a central role in power generation, conditioning, and conversion technologies and therefore promoting improvements in the efficiency of these materials is essential for our future energy needs. The losses generated by the magnetic core materials by hysteretic, acoustic, and/or eddy currents have a great impact on efficiency. A survey of soft magnetic materials for energy applications will be discussed with a focus on improvement in performance using novel soft magnetic materials designed for these power applications. A group of premiere soft magnetic materials -- nanocrystalline soft magnetic alloys -- will be highlighted for their potential in addressing energy efficiency. These materials are made up of nanocrystalline magnetic transition metal-rich grains embedded within an intergranular amorphous matrix, obtained by partial devitrification of melt-spun amorphous ribbons. The nanoscale grain size results in a desirable combination of large saturation induction, low coercivity, and moderate resistivity unobtainable in conventional soft magnetic alloys. The random distribution of these fine grains causes a reduction in the net magnetocrystalline anisotropy, contributing to the excellent magnetic properties. Recently developed (Fe,Co,Ni)88Zr7B4Cu1 alloys will be discussed with a focus on the microstructure/magnetic property relationship and their effects on the energy efficiency of these materials for AC applications.

Willard, Matthew

2012-02-01

166

Direct energy conversion for D-³He reactor  

Microsoft Academic Search

Results of particle simulation indicate that ExB drift is available for the purpose of ion energy selection, which is necessary for direct energy conversion. High energy conversion rate of the traveling wave direct energy converter up to 0.8 is obtained both from orbit calculation and from computer simulation as a result of improvement of proton beam modulation. Computer simulation using

Hideaki Katayama; Kunihiro Sato; Fujio Miyawaki

1995-01-01

167

Flux and conversion of solar-wind energy in the transition region of the magnetosphere  

Microsoft Academic Search

The flux transferred from the solar wind to the earth magnetosphere is calculated. It is shown that the Poynting-vector flux transferred to the reconnection region is primarily generated in the transition region between the detached-shock front and the magnetopause because of the deceleration of the solar wind and the partial conversion of its kinetic energy into magnetic energy. The dependence

M. I. Pudovkin; V. S. Semenov

1986-01-01

168

Mitigation of voltage dips and swells in grid-connected wind energy conversion systems  

Microsoft Academic Search

This paper investigates two methods for mitigation of voltage dips and voltage swells in a grid to which a wind energy conversion system (WECS) is connected. The two mitigation methods are the dynamic voltage regulator (DVR), and the static compensator (STATCOM). The wind energy system employs permanent magnet synchronous generator (PMSG). It is well known that the voltage dips affect

Mona N. Eskander; Sanaa I. Amer

2009-01-01

169

La Conversion Fotovoltaica de la Energia Solar (Photovoltaic Conversion of Solar Energy).  

National Technical Information Service (NTIS)

The volume outlines the principles, techniques, and possibilities of solar energy use through photovoltaic conversion, and also develops a strategy for the future, which may help to improve Spain's energy situation. The document covers the main components...

P. Pezuela F. Ruedo

1981-01-01

170

Progress on PEP-II magnet power conversion system  

SciTech Connect

The various power systems for supplying the PEP-II DC magnets rely exclusively on switchmode conversion, utilizing a variety of means depending on the requirements. All of the larger power supplies, ranging from 10 to 200 kW, are powered from DC sources utilizing rectified 480 V AC. Choppers can be used for the series connected strings, but for smaller groups and individual magnets, inverters driving high-frequency transformers with rectifiers comprise the best approach. All of the various systems use a ``building block`` approach of multiple standard-size units connected in series or parallel to most cost-effectively deal with a great range of voltage and current requirements. Utilization of existing infrastructure from PEP-I has been a cost-effective determinant. Equipment is being purchased either off-the-shelf, through performance specification, or by hardware purchase based on design-through-prototype. The corrector magnet power system, utilizing inexpensive, off-the-shelf, four-quadrant switching motor-controllers, has already proven very reliable: 120 of the total of 900 units have been running on the injection system for four months with no failures.

Bellomo, P.; Genova, L. [Stanford Linear Accelerator Center, Menlo Park, CA (United States); Jackson, T. [Lawrence Berkeley National Lab., CA (United States); Shimer, D. [Lawrence Livermore National Lab., CA (United States)

1996-06-04

171

Coronal Magnetic Energy Releases  

NASA Astrophysics Data System (ADS)

This book brings together a variety of review articles on dynamical phenomena in the solar corona in order to work out the unifying aspects of magnetic energy releases. The experimental data from groundbased methods of radio astronomy as well as from satellites are also discussed. The book addresses researchers in astrophysics, and planetary science but should also be accessible to graduate students.

Benz, Arnold O.; Krüger, Albrecht

172

Engineering Interfaces for Photovoltaic Energy Conversion  

NASA Astrophysics Data System (ADS)

Dye-sensitized solar cells (DSSCs) and the related quantum dot-sensitized solar cells (QDSSCs) show promise as inexpensive, efficient next-generation photovoltaic technologies. A typical cell design consists of a sensitizer chemisorbed to a nanoporous TiO2 substrate; the sensitizer absorbs a photon and an excited electron is injected into the TiO2 where it diffuses to the anode. However, many devices suffer from a high rate of electron-hole recombination at the interface between TiO2 and the hole conductive material, leading to reduced conversion efficiency. In this work we explore whether a passivating layer at the interface can improve efficiency by acting as a barrier against electron recombination. We have studied both organic and inorganic approaches to modifying the interfacial properties in DSSC and QDSSC devices. In studies of CdS-based QDSSCs, a series of organic self-assembled monolayers were formed at the interface, and their effect on CdS uptake and resulting optoelectronic and device properties was investigated. In DSSCs, nanoscale inorganic dielectric films of different thicknesses were applied to the interface using atomic layer deposition prior to dye absorption. The effect on device performance was measured experimentally and compared with predictions from kinetic models. The results of these investigations will be discussed in the context of the ability of interface engineering to improve photovoltaic energy conversion.

Bent, Stacey

2011-03-01

173

Rotating flux compressor for energy conversion  

SciTech Connect

The rotating flux compressor (RFC) converts rotational kinetic energy into an electrical output pulse which would have higher energy than the electrical energy initially stored in the compressor. An RFC has been designed in which wedge-shaped rotor blades pass through the air gaps between successive turns of a solenoid, the stator. Magnetic flux is generated by pulsing the stator solenoids when the inductance is a maximum, i.e., when the flux fills the stator-solenoid volume. Connecting the solenoid across a load conserves the flux which is compressed within the small volume surrounding the stator periphery when the rotor blades cut into the free space between the stator plates, creating a minimum-inductance condition. The unique features of this design are: (1) no electrical connections (brushes) to the rotor; (2) no conventional windings; and (3) no maintenance. The device has been tested up to 5000 rpm of rotor speed.

Chowdhuri, P.; Linton, T.W.; Phillips, J.A.

1983-01-01

174

Modeling and analysis of energy conversion systems  

SciTech Connect

An investigation was conducted to assess the need for and the feasibility of developing a computer code that could model thermodynamic systems and predict the performance of energy conversion systems. To assess the market need for this code, representatives of a few industrial organizations were contacted, including manufacturers, system and component designers, and research personnel. Researchers and small manufacturers, designers, and installers were very interested in the possibility of using the proposed code. However, large companies were satisfied with the existing codes that they have developed for their own use. Also, a survey was conduced of available codes that could be used or possibly modified for the desired purpose. The codes were evaluated with respect to a list of desirable features, which was prepared as a result of the survey. A few publicly available codes were found that might be suitable. The development, verification, and maintenance of such a code would require a substantial, ongoing effort. 21 refs.

Den Braven, K.R. (Idaho Univ., Moscow, ID (USA). Dept. of Mechanical Engineering); Stanger, S. (EG and G Idaho, Inc., Idaho Falls, ID (USA))

1990-10-01

175

Engineered nanomaterials for solar energy conversion.  

PubMed

Understanding how to engineer nanomaterials for targeted solar-cell applications is the key to improving their efficiency and could lead to breakthroughs in their design. Proposed mechanisms for the conversion of solar energy to electricity are those exploiting the particle nature of light in conventional photovoltaic cells, and those using the collective electromagnetic nature, where light is captured by antennas and rectified. In both cases, engineered nanomaterials form the crucial components. Examples include arrays of semiconductor nanostructures as an intermediate band (so called intermediate band solar cells), semiconductor nanocrystals for multiple exciton generation, or, in antenna-rectifier cells, nanomaterials for effective optical frequency rectification. Here, we discuss the state of the art in p-n junction, intermediate band, multiple exciton generation, and antenna-rectifier solar cells. We provide a summary of how engineered nanomaterials have been used in these systems and a discussion of the open questions. PMID:23298882

Mlinar, Vladan

2013-01-08

176

A new, versatile Stirling energy conversion unit  

SciTech Connect

A new concept in Stirling engine technology is embodied in the ''Base Engine'' now being developed at Stirling Thermal Motors, Inc. This is a versatile energy conversion unit suitable for many different applications and heat sources. The Base Engine, rated at 40 kw at 2800 rpm, is a four cylinder, double acting, variable displacement Stirling engine. It incorporates remote-heating technology with a stacked-heat-exchanger configuration and a liquid metal heat pipe connected to a distinctly separate combustor or other heat source. It specifically emphasizes high efficiency over a wide range of operating conditions, long life, low manufacturing cost and low material cost. This paper describes the Base Engine, its design philosophy and approach, its projected performance, and some of its more attractive applications.

Meijer, R.J.; Ziph, B.

1982-08-01

177

Engineered nanomaterials for solar energy conversion  

NASA Astrophysics Data System (ADS)

Understanding how to engineer nanomaterials for targeted solar-cell applications is the key to improving their efficiency and could lead to breakthroughs in their design. Proposed mechanisms for the conversion of solar energy to electricity are those exploiting the particle nature of light in conventional photovoltaic cells, and those using the collective electromagnetic nature, where light is captured by antennas and rectified. In both cases, engineered nanomaterials form the crucial components. Examples include arrays of semiconductor nanostructures as an intermediate band (so called intermediate band solar cells), semiconductor nanocrystals for multiple exciton generation, or, in antenna-rectifier cells, nanomaterials for effective optical frequency rectification. Here, we discuss the state of the art in p-n junction, intermediate band, multiple exciton generation, and antenna-rectifier solar cells. We provide a summary of how engineered nanomaterials have been used in these systems and a discussion of the open questions.

Mlinar, Vladan

2013-02-01

178

Thermoelectric energy conversion with solid electrolytes.  

PubMed

The alkali metal thermoelectric converter (AMTEC) is a device for the direct conversion of heat to electrical energy. The sodium ion conductor beta"- alumina is used to form a high-temperature regenerative concentration cell for elemental sodium. An AMTEC of mature design should have an efficiency of 20 to 40 percent, a power density of 0.5 kilowatt per kilogram or more, no moving parts, low maintenance requirements, high durability, and efficiency independent of size. It should be usable with high-temperature combustion, nuclear, or solar heat sources. Experiments have demonstrated the feasibility of the AMTEC and confirmed the theoretical analysis of the device. A wide range of applications from aerospace power to utility power plants appears possible. PMID:17748444

Cole, T

1983-09-01

179

Comparison of local energy conversion estimates from Cluster with global MHD simulations  

NASA Astrophysics Data System (ADS)

The local energy conversion across the magnetopause has been estimated with Cluster for two magnetopause crossings. A load region, conversion from magnetic to particle energy, was identified on the dayside high-latitude magnetopause during south/dawnward IMF. Another crossing of the dawn flank magnetotail during dominantly duskward IMF was identified as a generator region where the magnetosphere is loaded with magnetic energy. The observations have been compared to results of the BATS-R-US global MHD simulation based on observed IMF conditions. BATS-R-US reproduced the magnetopause regions crossed by Cluster as a load and a generator region, correspondingly. The magnitude of the estimated energy conversion from Cluster and the model are in quite good agreement. BATS-R-US cannot reproduce the observed sharp magnetopause and some topological differences between the observations and the model occur.

Rosenqvist, L.; Opgenoorth, H. J.; Rastaetter, L.; Vaivads, A.; Dandouras, I.; Buchert, S.

2008-11-01

180

Output power maximization of low-power wind energy conversion systems revisited: Possible control solutions  

Microsoft Academic Search

This paper discusses the problem of output power maximization for low-power wind energy conversion systems operated in partial load. These systems are generally based on multi-polar permanent-magnet synchronous generators, who exhibit significant efficiency variations over the operating range. Unlike the high-power systems, whose mechanical-to-electrical conversion efficiency is high and practically does not modify the global optimum, the low-power systems global

Ciprian Vlad; Iulian Munteanu; Antoneta Iuliana Bratcu; Emil Ceang?

2010-01-01

181

Progress on PEP-II Magnet Power Conversion System?  

SciTech Connect

The various power systems for supplying the PEP-II DCmagnets rely exclusively on switch mode conversion, utilizing a varietyof means depending on the requirements. All of the larger power supplies,ranging from 10 to 200 kW, are powered from DC sources utilizingrectified 480 V AC. Choppers can be used for the series connectedstrings, but for smaller groups and individual magnets, inverters drivinghigh-frequency transformers with secondary rectifiers comprise the bestapproach. All of the various systems use a "building block" approach ofmultiple standard-size units connected in series or parallel to mostcost-effectively deal with a great range of voltage and currentrequirements. Utilization of existing infrastructure from PEP-I has beena cost-effective determinant. Equipment is being purchased eitheroff-the-shelf, through performance specification, or by hardware purchasebased on design-through-prototype. The corrector magnet power system,utilizing inexpensive, off-the-shelf four-quadrant switching motorcontrollers, has already proven very reliable: 120 of the total of 900units have been running on the injection system for four months with nofailures.

Bellomo, P.; Genova, L.; Jackson, T.; Shimer, D.

1996-06-01

182

Research on multiple boost converter based on MW-level wind energy conversion system  

Microsoft Academic Search

This paper is mainly about the wind energy conversion system with a rated output of 1.2 MW which applied to the variable speed constant frequency wind energy system (VSCF). It utilizes the AC-DC-AC power converter to deliver the high-level power energy from permanent-magnet generators to the grid. As the important section of DC energy delivering link in the system, a

Xiong Xin; Liang Hui

2005-01-01

183

Energy conversion for megawatt space power systems  

SciTech Connect

Large nuclear space power systems capable of continuously producing over one megawatt of electrical power for a several year period will be needed in the future. This paper presents the results of a study to compare applicable conversion technologies which were deemed to be ready for a time period of 1995 and beyond. A total of six different conversion technologies were studied in detail and compared on the basis of conversion efficiency, radiator area, overall system mass, and feasibility. Three static, modular conversion technologies were considered; these include: AMTEC, thermionic, and thermoelectric conversion. The other three conversion technologies are heat engines which involve dynamic components. The dynamic systems analyzed were Brayton, Rankine, and the free piston Stirling engine. Each of the conversion techniques was also examined for limiting characteristics and an attempt was made to identify common research needs and enabling technologies.

Ewell, R.

1983-08-01

184

Ocean thermal energy conversion: Perspective and status  

SciTech Connect

The use of the thermal gradient between the warm surface waters and the deep cold waters of tropical oceans was first proposed by J. A. d'Arsonval in 1881 and tried unsuccessfully be George Claude in 1930. Interest in Ocean Thermal Energy Conversion (OTEC) and other renewable energy sources revived in the 1970s as a result of oil embargoes. At that time, the emphasis was on large floating plants miles from shore producing 250--400 MW for maintained grids. When the problems of such plants became better understood and the price of oil reversed its upward trend, the emphasis shifted to smaller (10 MW) shore-based plants on tropical islands. Such plants would be especially attractive if they produce fresh water as a by-product. During the past 15 years, major progress has been made in converting OTEC unknowns into knowns. Mini-OTEC proved the closed-cycle concept. Cost-effective heat-exchanger concepts were identified. An effective biofouling control technique was discovered. Aluminum was determined to be promising for OTEC heat exchangers. Heat-transfer augmentation techniques were identified, which promised a reduction on heat-exchanger size and cost. Fresh water was produced by an OTEC open-cycle flash evaporator, using the heat energy in the seawater itself. The current R D emphasis is on the design and construction of a test facility to demonstrate the technical feasibility of the open-cycle process. The 10 MW shore-based, closed-cycle plant can be built with today's technology; with the incorporation of a flash evaporator, it will produce fresh water as well as electrical power -- both valuable commodities on many tropical islands. The open-cycle process has unknowns that require solution before the technical feasibility can be demonstrated. The economic viability of either cycle depends on reducing the capital costs of OTEC plants and on future trends in the costs of conventional energy sources. 7 refs.

Thomas, A.; Hillis, D.L.

1990-01-01

185

Ocean thermal energy conversion: Perspective and status  

NASA Astrophysics Data System (ADS)

The use of the thermal gradient between the warm surface waters and the deep cold waters of tropical oceans was first proposed by J. A. d'Arsonval in 1881 and tried unsuccessfully by George Claude in 1930. Interest in Ocean Thermal Energy Conversion (OTEC) and other renewable energy sources revived in the 1970s as a result of oil embargoes. At that time, the emphasis was on large floating plants miles from shore producing 250 to 400 MW for maintained grids. When the problems of such plants became better understood and the price of oil reversed its upward trend, the emphasis shifted to smaller (10 MW) shore based plants on tropical islands. Such plants would be especially attractive if they produce fresh water as a by-product. During the past 15 years, major progress has been made in converting OTEC unknowns into knowns. Mini-OTEC proved the closed cycle concept. Cost effective heat exchanger concepts were identified. An effective biofouling control technique was discovered. Aluminum was determined to be promising for OTEC heat exchangers. Heat transfer augmentation techniques were identified, which promised a reduction on heat exchanger size and cost. Fresh water was produced by an OTEC open cycle flash evaporator, using the heat energy in the seawater itself. The current R and D emphasis is on the design and construction of a test facility to demonstrate the technical feasibility of the open cycle process. The 10 MW shore-based, closed cycle plant can be built with today's technology; with the incorporation of a flash evaporator, it will produce fresh water as well as electrical power; both valuable commodities on many tropical islands. The open cycle process has unknowns that require solution before the technical feasibility can be demonstrated. The economic viability of either cycle depends on reducing the capital costs of OTEC plants and on future trends in the costs of conventional energy sources.

Thomas, Anthony; Hillis, David L.

186

Nanomaterials for energy conversion and storage.  

PubMed

Nanostructured materials are advantageous in offering huge surface to volume ratios, favorable transport properties, altered physical properties, and confinement effects resulting from the nanoscale dimensions, and have been extensively studied for energy-related applications such as solar cells, catalysts, thermoelectrics, lithium ion batteries, supercapacitors, and hydrogen storage systems. This review focuses on a few select aspects regarding these topics, demonstrating that nanostructured materials benefit these applications by (1) providing a large surface area to boost the electrochemical reaction or molecular adsorption occurring at the solid-liquid or solid-gas interface, (2) generating optical effects to improve optical absorption in solar cells, and (3) giving rise to high crystallinity and/or porous structure to facilitate the electron or ion transport and electrolyte diffusion, so as to ensure the electrochemical process occurs with high efficiency. It is emphasized that, to further enhance the capability of nanostructured materials for energy conversion and storage, new mechanisms and structures are anticipated. In addition to highlighting the obvious advantages of nanostructured materials, the limitations and challenges of nanostructured materials while being used for solar cells, lithium ion batteries, supercapacitors, and hydrogen storage systems have also been addressed in this review. PMID:23455759

Zhang, Qifeng; Uchaker, Evan; Candelaria, Stephanie L; Cao, Guozhong

2013-04-01

187

Science of Nanofluidics and Energy Conversion  

NASA Astrophysics Data System (ADS)

The emerging subject of nanofluidics, where solids and fluids interact closely at the nanoscale, has exhibited radically different from their macroscopic counterparts (and sometimes counterintuitive), and yet relatively less explored. On the other hand, the resulting unique properties may contribute to a number of innovative functions with fascinating applications. Among various exciting potential applications, an important and ever expanding one is to provide alternative solutions to energy conversion with high efficiency, including energy absorption, actuation and harvesting. In this dissertation, we first report a novel protection mechanism of energy capture through which an intensive impact or blast energy can be effectively mitigated based on a nonwetting liquid-nanoporous material system. The captured energy is stored in nanopores in the form of potential energy of intercalated water molecules for a while, and not necessarily converted to other forms of energy (e.g. heat). At unloading stage, the captured energy will be released gradually due to the hydrophobic inner surfaces of nanopores through the diffusion of water molecules out of nanopores, thus making this system reusable. Several key controlling factors including impacting velocity, nanopore size, nanopore structure, and liquid phase have been investigated on the capacity of energy capture. The molecular mechanism is elucidated through the study of water molecular distributions inside nanpores. These molecular dynamic (MD) findings are quantitatively verified by a parallel blast experiment on a zeolite/water system. During the transport of confined liquid molecules, the friction resistance exerted by solid atoms of nanopores to liquid molecules will dissipate part of energy, and is highly dependent of temperature of liquid molecules and wall morphology of nanopores. Using MD simulations, the effects of temperature and wall roughness on the transport resistance of water molecules inside nanopores are investigated in Chapter 3. The effective shear stress and nominal viscosity that dominate the nanofluidic transport resistance are extracted and coupled with the nanopore size, transport rate, and liquid property. The molecular-level mechanisms are revealed through the study of the density profile and hydrogen bonding of confined liquid molecules. A parallel experiment on a nanoporous carbon-liquid system is carried out and qualitatively verifies MD findings. Motived by the well-known thermo- and electro-capillary effect, Chapter 4 and Chapter 5 present a conceptual design of thermal and electric actuation system by adjusting the relative hydrophobicity of a liquid-nanoporous system through a thermal and electric field, respectively. The thermally and electrically dependent infiltration behaviors of liquids into nanopores are analyzed by using MD simulations. The fundamental molecular characteristics, including the density profile, contact angle, and surface tension of the confined liquid molecules, are examined to reveal underlying mechanisms. The energy density, power density, and efficiency of both thermal and electric actuation systems are explored and their variations with pore size, solid phase, and liquid phase are evaluated. Thermally and electrically controlled infiltration experiments on a zeolite-water /electrolyte solution system are performed accordingly to qualitatively validate these findings. These energy actuation systems can also become high density thermal or electric storage devices with proper designs. Energy harvesting by the flow of a hydrochloric acid-water solution through a nanopore is explored using atomistic simulations in the last chapter. Through ion configurations near the pore wall, an averaged ion drifting velocity is determined, and the induced voltage along the axial direction is obtained as a function of key material parameters, including the applied flow rate, environmental temperature, solution concentration and nanopore size. The molecular mechanism of ion hopping and motion is revealed. This study shed light on harvesting

Xu, Baoxing

188

Effect of a random magnetic field on active-sterile neutrino conversion in the supernova core  

NASA Astrophysics Data System (ADS)

The active-sterile neutrino conversion is studied for a neutrino propagating in the axial potential generated by a magnetized electron plasma in the supernova medium. We consider the effects of a random magnetic field Brms on the average neutrino conversion probability. We obtain the constraint on ?m2 and sin22? for different strengths of the random magnetic fields by considering the positive definiteness of the average neutrino conversion probability inside the supernova core. Our calculation shows that, to have ?m2<~ keV2, a random magnetic field of Brms<~0.63×1014 G is preferable.

Sahu, Sarira; Bannur, Vishnu M.

2000-01-01

189

Solar energy conversion using surface plasmons for broadband energy transport  

NASA Astrophysics Data System (ADS)

A new strategy for efficient solar energy conversion based on parallel processing with surface plasmons is introduced. The approach is unique in identifying: (1) a broadband carrier with suitable range for energy transport, and (2) a technique to extract more energy from the more energetic photons, without sequential losses or unique materials for each frequency band. The aim is to overcome the fundamental losses associated with the broad solar spectrum and to achieve a higher level of spectrum splitting than has been possible in semiconductor systems.

Anderson, L. M.

190

Test program for wind energy conversion system GROWIAN  

Microsoft Academic Search

The planned test program for wind energy conversion is described. Measurements made of wind distribution, efficiency of energy conversion, dynamic effects, electric behavior, optimization of control, and environmental impact, like sound and TV interferences are discussed. Wind distribution is measured far enough in front of the windmill, just before the blades, and behind the rotor by a grid arrangement of

F. Koerber

1982-01-01

191

Some preliminary considerations on photovoltaic conversion of solar energy  

Microsoft Academic Search

Tentative calculations on the feasibility, cost effectiveness, and overall reliability of solar energy via photovoltaic conversion are carried out. It is estimated that the cost of solar energy conversion will have to be cut by factors of 100 to 200 for it to become competitive with other sources of large-scale power in the foreseeable future. The importance of exploitation of

A. Egidi; G. V. Pallottino

1976-01-01

192

Analysis of frequency up-conversion based vibration energy harvesting  

Microsoft Academic Search

Mechanical frequency up-conversion has been suggested by many researchers in order to increase power density of kinetic energy harvesters. In this paper analytical analysis of frequency up-conversion mechanism has been carried out in some detail. It has been shown that sources of actuation for a frequency increased generator can be categorized as force limited and displacement limited sources. Maximum energy

Khalid Ashraf; John Ojur Dennis

2011-01-01

193

Wind Energy Conversion System Analysis Model (WECSAM) computer program documentation  

Microsoft Academic Search

Described is a computer-based wind energy conversion system analysis model (WECSAM) developed to predict the technical and economic performance of wind energy conversion systems (WECS). The model is written in CDC FORTRAN V. The version described accesses a data base containing wind resource data, application loads, WECS performance characteristics, utility rates, state taxes, and state subsidies for a six state

W. T. Downey; P. L. Hendrick

1982-01-01

194

Power electronics applications in wind energy conversion system: A review  

Microsoft Academic Search

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

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

2010-01-01

195

Development of Radioisotope Energy Conversion Systems - efficient Radioisotopic Power  

Microsoft Academic Search

Topical area of the conference: (10) Space Power and Propulsion . Abstract: The topic of this paper is the development of the Radioisotope Energy Conversion System (RECS) in a project which is utilizing analytical computational assisted Design and experimental Research in the investigation of fluorescers and effective transducers for the conversion of energy.

Eric V. Steinfelds; Tushar K. Ghosh; Mark A. Prelas; Robert V. Tompson; Sudarshan K. Loyalka

196

Direct conversion of plasma energy to electricity for mirror fusion reactors  

Microsoft Academic Search

Direct conversion of plasma and ion beam energy to electricity for mirror fusion reactors is described. Selective leakage, magnetic expansion, electron separation, deceleration, and collection of ions are discussed. An experiment testing all processes except selective leakage gave an overall efficiency of 86.5 + or - 1.5% for a 22-stage collector. Computer calculations of these same processes gave an efficiency

R. W. Moir; W. L. Barr; G. A. Carlson

1974-01-01

197

Power Optimization in a Grid-Connected Wind Energy Conversion System  

Microsoft Academic Search

This paper discusses the performance of a grid connected variable speed wind energy conversion system consisting of a wind turbine coupled to a permanent magnet synchronous generator (PMSG) through a gearbox. The generator output voltage which varies with wind velocity and grid voltage is rectified and fed to a DC\\/DC chopper. The duty ratio of the chopper is adjusted to

P. Anandavel; K. Rajambal; C. Chellamuthu

2005-01-01

198

Optimisation of a Small Non Controlled Wind Energy Conversion System for Stand-Alone Applications  

Microsoft Academic Search

This article proposes a method to optimize the design of a small fixed-voltage wind energy conversion system (WECS). The system is composed of commercially available elements which are: a small horizontal axe wind turbine, a one- stage gearbox, a permanent magnet synchronous generator, a diode bridge and a battery bank. As there are no controlled devices on the system, the

Miguel Lopez; Philippe Dessante; Dario Morales; Jean-Claude Vannier; Daniel Sadarnac

199

Towards improved photovoltaic conversion using dilute magnetic semiconductors (abstract only).  

PubMed

Present photovoltaic devices, based on p/n junctions, are limited from first principles to maximal efficiencies of 31% (40% under full solar concentration; Shockley and Queisser 1961 J. Appl. Phys. 32 510). However, more innovative schemes may overcome the Shockley-Queisser limit since the theoretical maximal efficiency of solar energy conversion is higher than 85% (Harder and Würfel 2003 Semicond. Sci. Technol. 18 S151). To date, the only practical realization of such an innovative scheme has been multi-junction devices, which at present hold the world record for efficiency at nearly 41% at significant solar concentration (US DOE news site: http://www.energy.gov/news/4503.htm). It has been proposed that one could make use of the solar spectrum in much the same way as the multi-junction devices do but in a single cell, using impurity induced intermediate levels to create gaps of different sizes. This intermediate level semiconductor (ILSC) concept (Green and Wenham 1994 Appl. Phys. Lett. 65 2907; Luque and Martí1997 Phys. Rev. Lett. 78 5014) has a maximal efficiency similar to that of multi-junction devices but suffers from prohibitively large non-radiative recombination rates. We here propose to use a ferromagnetic impurity scheme in order to reduce the non-radiative recombination rates while maintaining the high theoretical maximum efficiency of the ILSC scheme, that is about 46%. Using density functional theory calculations, the electronic and energetic properties of transition metal impurities for a wide range of semiconductors have been analysed. Of the several hundred compounds studied, only a few fulfil the design criteria that we present here. As an example, wide gap AlP is one of the most promising compounds. It was found that inclusion of significant amounts of Mn in AlP induces band structures providing conversion efficiencies potentially close to the theoretical maximum, with an estimated Curie temperature reaching above 100 K. PMID:21693888

Olsson, Pär; Guillemoles, J-F; Domain, C

2008-01-24

200

Solar energy conversion and storage systems for the future  

Microsoft Academic Search

The possible utilization of solar energy in its various manifestations such as heat, winds, tides, and ocean thermal gradients is reviewed. Methods of solar energy collection, conversion, and utilization are examined, along with the solar energy potential. Special attention is given to various systems for meeting the needs of solar energy storage. The systems considered include: (1) thermal energy storage

R. Ramakumar; H. J. Allison; W. L. Hughes

1974-01-01

201

Open cycle ocean thermal energy conversion system  

SciTech Connect

An improved open cycle ocean thermal energy conversion system includes a flash evaporator for vaporizing relatively warm ocean surface water and an axial flow, elastic fluid turbine having a vertical shaft and axis of rotation. The warm ocean water is transmitted to the evaporator through a first prestressed concrete skirt-conduit structure circumferentially situated about the axis of rotation. The unflashed warm ocean water exits the evaporator through a second prestressed concrete skirt-conduit structure located circumferentially about and radially within the first skirt-conduit structure. The radially inner surface of the second skirt conduit structure constitutes a cylinder which functions as the turbine's outer casing and obviates the need for a conventional outer housing. The turbine includes a radially enlarged disc element attached to the shaft for supporting at least one axial row of radially directed blades through which the steam is expanded. A prestressed concrete inner casing structure of the turbine has upstream and downstream portions respectively situated upstream and downstream from the disc element. The radially outer surfaces of the inner casing portions and radially outer periphery of the axially interposed disc cooperatively form a downwardly radially inwardly tapered surface. An annular steam flow path of increasing flow area in the downward axial direction is radially bounded by the inner and outer prestressed concrete casing structures. The inner casing portions each include a transversely situated prestressed concrete circular wall for rotatably supporting the turbine shaft and associated structure. The turbine blades are substantially radially coextensive with the steam flow path and receive steam from the evaporator through an annular array of prestressed concrete stationary vanes which extend between the inner and outer casings to provide structural support there for and impart a desired flow direction to the steam. 10 figs.

Wittig, J.M.

1980-02-19

202

Open cycle ocean thermal energy conversion system  

SciTech Connect

An improved open cycle ocean thermal energy conversion system including a flash evaporator for vaporizing relatively warm ocean surface water and an axial flow, elastic fluid turbine having a vertical shaft and axis of rotation. The warm ocean water is transmitted to the evaporator through a first prestressed concrete skirt-conduit structure circumferentially situated about the axis of rotation. The unflashed warm ocean water exits the evaporator through a second prestressed concrete skirt-conduit structure located circumferentially about and radially within the first skirt-conduit structure. The radially inner surface of the second skirt conduit structure constitutes a cylinder which functions as the turbine's outer casing and obviates the need for a conventional outer housing. The turbine includes a radially enlarged disc element attached to the shaft for supporting at least one axial row of radially directed blades through which the steam is expanded. A prestressed concrete inner casing structure of the turbine has upstream and downstream portions respectively situated upstream and downstream from the disc element. The radially outer surfaces of the inner casing portions and radially outer periphery of the axially interposed disc cooperatively form a downwardly radially inwardly tapered surface. An annular steam flowpath of increasing flow area in the downward axial direction is radially bounded by the inner and outer prestressed concrete casing structures. The inner casing portions each include a transversely situated prestressed concrete circular wall for rotatably supporting the turbine shaft and associated structure. The turbine blades are substantially radially coextensive with the steam flowpath and receive steam from the evaporator through an annular array of prestressed concrete stationary vanes which extend between the inner and outer casings to provide structural support therefor and impart a desired flow direction to the steam.

Wittig, J. Michael (West Goshen, PA)

1980-01-01

203

Open cycle ocean thermal energy conversion system  

DOEpatents

An improved open cycle ocean thermal energy conversion system including a flash evaporator for vaporizing relatively warm ocean surface water and an axial flow, elastic fluid turbine having a vertical shaft and axis of rotation. The warm ocean water is transmitted to the evaporator through a first prestressed concrete skirt-conduit structure circumferentially situated about the axis of rotation. The unflashed warm ocean water exits the evaporator through a second prestressed concrete skirt-conduit structure located circumferentially about and radially within the first skirt-conduit structure. The radially inner surface of the second skirt conduit structure constitutes a cylinder which functions as the turbine's outer casing and obviates the need for a conventional outer housing. The turbine includes a radially enlarged disc element attached to the shaft for supporting at least one axial row of radially directed blades through which the steam is expanded. A prestressed concrete inner casing structure of the turbine has upstream and downstream portions respectively situated upstream and downstream from the disc element. The radially outer surfaces of the inner casing portions and radially outer periphery of the axially interposed disc cooperatively form a downwardly radially inwardly tapered surface. An annular steam flowpath of increasing flow area in the downward axial direction is radially bounded by the inner and outer prestressed concrete casing structures. The inner casing portions each include a transversely situated prestressed concrete circular wall for rotatably supporting the turbine shaft and associated structure. The turbine blades are substantially radially coextensive with the steam flowpath and receive steam from the evaporator through an annular array of prestressed concrete stationary vanes which extend between the inner and outer casings to provide structural support therefor and impart a desired flow direction to the steam.

Wittig, J. Michael (West Goshen, PA)

1980-01-01

204

Superconducting magnetic energy storage  

SciTech Connect

Recent programmatic developments in Superconducting Magnetic Energy Storage (SMES) have prompted renewed and widespread interest in this field. In mid 1987 the Defense Nuclear Agency, acting for the Strategic Defense Initiative Office, issued a request for proposals for the design and construction of SMES Engineering Test Model (ETM). Two teams, one led by Bechtel and the other by Ebasco, are now engaged in the first phase of the development of a 10 to 20 MWhr ETM. This report presents the rationale for energy storage on utility systems, describes the general technology of SMES, and explains the chronological development of the technology. The present ETM program is outlined; details of the two projects for ETM development are described in other papers in these proceedings. The impact of high T/sub c/ materials on SMES is discussed. 69 refs., 3 figs., 3 tabs.

Hassenzahl, W.

1988-08-01

205

Direct energy conversion system for D(3)He fusion  

Microsoft Academic Search

A novel and highly efficient direct energy conversion system is proposed for utilizing D(3)-He fueled fusion. In order to convert kinetic energy of ions, we applied a pair of direct energy conversion systems each of which has a cusp-type DEC and a traveling wave DEC (TWDEC). In a cusp-type DEC, electrons are separated from the escaping ions at the first

Y. Tomita; L. Y. Shu; H. Momota

1993-01-01

206

NASA-OAST program in photovoltaic energy conversion  

NASA Astrophysics Data System (ADS)

The NASA program in photovoltaic energy conversion includes research and technology development efforts on solar cells, blankets, and arrays. The overall objectives are to increase conversion efficiency, reduce mass, reduce cost, and increase operating life. The potential growth of space power requirements in the future presents a major challenge to the current state of technology in space photovoltaic systems.

Mullin, J. P.; Flood, D. J.

207

Potential methods and perspectives of solar energy conversion via photocatalytic processes. [345 references  

Microsoft Academic Search

Existing methods of solar energy conversion are classified into 4 types: (1) thermal; (2) photophysical; (3) photochemical (including photoelectrolysis); and (4) photobiological (based on natural photosynthesis). Thermal conversion under direct conditions is an attractive method of conversion, but further conversion of heat into mechanical or electrical energy make thermal conversion seem unsuitable for large-scale use. Methods based on direct conversion

K. I. Zamaraev; V. N. Parmon

1980-01-01

208

Energy considerations in vector magnetization models  

Microsoft Academic Search

Scalar magnetization model energy calculations, which are useful in calculating energy losses in open magnetization processes, are extended here to vector models. The energy loss is calculated as the difference between the energy input to the magnetic medium and the change in energy stored in the locally reversible component of the total magnetization. It is shown that under rotating magnetizing

Edward Dellatorre; Ann Reimers

2001-01-01

209

Low-frequency magnetic energy harvest using multiferroic composite plates  

NASA Astrophysics Data System (ADS)

It is shown with a theoretical bending model that a laminated plate with piezoelectric and piezomagnetic layers can be used to harvest magnetic energy at relatively low frequencies. The output electric power and the energy conversion efficiency are calculated. The load dependence of the magnetoelectric coupling coefficient is obtained.

Zhang, C. L.; Yang, J. S.; Chen, W. Q.

2010-05-01

210

Nanostructured Composite Materials for High Temperature Thermoelectric Energy Conversion.  

National Technical Information Service (NTIS)

The goals of this project were to synthesize, characterize and model bulk nanostructured composite materials for thermoelectric energy conversion applications. The objective was to produce materials which demonstrate an increase in intrinsic thermoelectri...

C. J. O'Connor

2012-01-01

211

An Overview of the Progress in Photoelectrochemical Energy Conversion.  

ERIC Educational Resources Information Center

Provides an overview of advances made in the field of photoelectrochemistry. Includes a short historical account of the development of the field, a review of the state-of-the-art of photoelectrochemical energy conversion and future prospects. (JN)

Parkinson, Bruce

1983-01-01

212

Potential Impact of Ocean Thermal Energy Conversion (OTEC) on Fisheries.  

National Technical Information Service (NTIS)

The commercial development of ocean thermal energy conversion (OTEC) operations will involve some environmental perturbations for which there is no precedent experience. The pumping of very large volumes of warm surface water and cold deep water and its s...

E. P. Myers D. E. Hoss W. M. Matsumoto D. S. Peters M. P. Seki

1986-01-01

213

Decreasing Geothermal Energy Conversion Costs with Advanced Materials.  

National Technical Information Service (NTIS)

If the Geothermal Technology Division (GTD) is to meet its programmatic objectives in hydrothermal fluid production and energy conversion, it is essential that new materials of construction be available. Level III Program Objectives include (1) reducing t...

L. E. Kukacka

1988-01-01

214

Ocean Thermal Energy Conversion (OTEC) Program. FY 1977 Program Summary.  

National Technical Information Service (NTIS)

An overview is given of the ongoing research, development, and demonstration efforts. Each of the DOE's Ocean Thermal Energy Conversion projects funded during fiscal year 1977 (October 1, 1976 through September 30, 1977) is described and each project's st...

1978-01-01

215

Potential Effects of Geothermal Energy Conversion on Imperial Valley Ecosystems.  

National Technical Information Service (NTIS)

This workshop on potential effects of geothermal energy conversion on the ecology of Imperial Valley brought together personnel of Lawrence Livermore Laboratory and many collaborators under the sponsorship of the ERDA Imperial Valley Environmental Project...

J. H. Shinn

1976-01-01

216

SWECS (Small Wind Energy Conversion Systems) Industry in the US.  

National Technical Information Service (NTIS)

The small wind energy conversion systems (SWECS) industry in the United States is reviewed from its early beginnings in the 1930's, through the federally supported work, to present uses of wind power. (ERA citation 09:019974)

V. Nelson

1984-01-01

217

Semiconductor Nanowires and Nanotubes for Energy Conversion  

NASA Astrophysics Data System (ADS)

In recent years semiconductor nanowires and nanotubes have garnered increased attention for their unique properties. With their nanoscale dimensions comes high surface area and quantum confinement, promising enhancements in a wide range of applications. 1-dimensional nanostructures are especially attractive for energy conversion applications where photons, phonons, and electrons come into play. Since the bohr exciton radius and phonon and electron mean free paths are on the same length scales as nanowire diameters, optical, thermal, and electrical properties can be tuned by simple nanowire size adjustments. In addition, the high surface area inherent to nanowires and nanotubes lends them towards efficient charge separation and superior catalytic performance. In thermoelectric power generation, the nanoscale wire diameter can effectively scatter phonons, promoting reductions in thermal conductivity and enhancements in the thermoelectric figure of merit. To that end, single-crystalline arrays of PbS, PbSe, and PbTe nanowires have been synthesized by a chemical vapor transport approach. The electrical and thermal transport properties of the nanowires were characterized to investigate their potential as thermoelectric materials. Compared to bulk, the lead chalcogenide nanowires exhibit reduced thermal conductivity below 100 K by up to 3 orders of magnitude, suggesting that they may be promising thermoelectric materials. Smaller diameters and increased surface roughness are expected to give additional enhancements. The solution-phase synthesis of PbSe nanowires via oriented attachment of nanoparticles enables facile surface engineering and diameter control. Branched PbSe nanowires synthesized by this approach showed near degenerately doped charge carrier concentrations. Compared to the bulk, the PbSe nanowires exhibited a similar Seebeck coefficient and a significant reduction in thermal conductivity in the temperature range 20 K to 300 K. Thermal annealing of the PbSe nanowires allowed their thermoelectric properties to be controllably tuned by increasing their carrier concentration or hole mobility. After optimal annealing, single PbSe nanowires exhibited a thermoelectric figure of merit (ZT) of 0.12 at 300 K. In addition, using a field-effect gated device, the Seebeck coefficient of single PbSe nanowires could be tuned from 64 to 193 muV?K-1. This direct electrical field control of the electrical conductivity and Seebeck coefficient suggests a powerful strategy for optimizing ZT in thermoelectric devices and these results represent the first demonstration of field-effect modulation of the thermoelectric figure of merit in a single semiconductor nanowire. This novel strategy for thermoelectric property modulation could prove especially important in optimizing the thermoelectric properties of semiconductors where reproducible doping is difficult to achieve. Recent theoretical work has shown large enhancements in ZT for single-crystal nanowires containing nanoscale interfaces along their lengths. M2O3(ZnO) n ( M = In, Ga, Fe) superlattice nanowires were synthesized via a novel solid-state diffusion approach to investigate this possible enhancement. Using atomic resolution Z-contrast STEM imaging a detailed structural analysis was performed on In2-xGaxO3(ZnO) n nanowires, leading to the discovery that octahedral inclusions within the superlattice structure are likely generated through a defect-assisted process. Single-nanowire thermal and electrical measurements on In2-x GaxO3(ZnO)n reveal a simultaneous improvement in all contributing factors to the thermoelectric figure of merit, giving an order of magnitude enhancement over similar bulk materials at room temperature. This is the first report of enhancement of all three thermoelectric parameters (Seebeck coefficient, electrical conductivity, and thermal resistivity) for a nanowire system. Photoelectrochemical water splitting is another exciting renewable energy application that can benefit from the high surface area of nanomaterials. Recently, (Ga1-xZnx)(N1-xOx) has gained

Fardy, Melissa Anne

218

Push-n-Go: A Dynamic Energy Conversion Lesson.  

ERIC Educational Resources Information Center

Focuses on the use of push and go toys to discuss with students how the toy acquires potential energy when work is done on it and how this energy is stored in the internal mechanism for later conversion into kinetic energy. (DDR)

Taylor, Beverly A. P.

1998-01-01

219

Research on energy storage for solar thermal conversion  

Microsoft Academic Search

Thermal energy storage (TES) for solar thermal energy conversion to electric power was studied. Major emphasis was placed on determining the relative merits of latent, sensible, and hybrid latent-sensible storage systems. The thermal energy storage systems evaluated are compatible with 10 MW and 100 MW steam power plants with TES delivery temperature ranges of 400 to 600 F and 900

J. L. Clayton

1978-01-01

220

Research on energy storage for solar thermal conversion. Final report  

Microsoft Academic Search

Thermal energy storage (TES) for solar thermal energy conversion to electric power was studied. Major emphasis was placed on determining the relative merits of latent, sensible, and hybrid latent-sensible storage systems. The thermal energy storage systems evaluated are compatible with 10 MW and 100 MW steam power plants with TES delivery temperature ranges of 400 to 600 F and 900

1978-01-01

221

Push-n-Go: A Dynamic Energy Conversion Lesson.  

ERIC Educational Resources Information Center

|Focuses on the use of push and go toys to discuss with students how the toy acquires potential energy when work is done on it and how this energy is stored in the internal mechanism for later conversion into kinetic energy. (DDR)|

Taylor, Beverly A. P.

1998-01-01

222

Biomass energy conversion: ecological, economic, and social constraints. Final report  

Microsoft Academic Search

Development of substitute energy sources in lieu of non-renewable fossil fuels was addressed. The study was based on the projection that by the turn of the century almost half of the world's oil, gas, and coal resources will be consumed. In this study, an analysis was made of biomass energy conversion and its ecological, social, economic, and energy constraints. Estimates

Pimentel

1977-01-01

223

Reliability assurance of turbine energy conversion systems  

Microsoft Academic Search

The Dynamic Isotope Power System (DIPS) is a 6-k (electric) space power system utilizing a ²³⁸Pu radioisotope heat source and a dual redundant closed Brayton cycle power conversion assembly. The DIPS program is currently funded to design, fabricate, and test a ground demonstration engineering unit. Primary objectives of the test will be to validate design and demonstrate performance and lifetime.

P. D. Rutherford; D. S. Burgess; S. Robb

1989-01-01

224

Energy production from biomass (Part 2): Conversion technologies.  

PubMed

The use of biomass to provide energy has been fundamental to the development of civilisation. In recent times pressures on the global environment have led to calls for an increased use of renewable energy sources, in lieu of fossil fuels. Biomass is one potential source of renewable energy and the conversion of plant material into a suitable form of energy, usually electricity or as a fuel for an internal combustion engine, can be achieved using a number of different routes, each with specific pros and cons. A brief review of the main conversion processes is presented, with specific regard to the production of a fuel suitable for spark ignition gas engines. PMID:12058830

McKendry, Peter

2002-05-01

225

A wideband magnetic energy harvester  

NASA Astrophysics Data System (ADS)

A wideband magnetic energy harvester is proposed by using a number of multiferroic composite fibers of different lengths which are connected in parallel or series. The structural theory is employed to characterize the magnetoelectroelastic behavior of the fibers. A global circuit analysis is then performed. It is shown that such a structure of energy harvester is capable of collecting the ambient magnetic energy over a wide frequency range.

Zhang, C. L.; Chen, W. Q.

2010-03-01

226

Thermoelectric energy conversion using nanostructured materials  

NASA Astrophysics Data System (ADS)

High performance thermoelectric materials in a wide range of temperatures are essential to broaden the application spectrum of thermoelectric devices. This paper presents experiments on the power and efficiency characteristics of lowand mid-temperature thermoelectric materials. We show that as long as an appreciable temperature difference can be created over a short thermoelectric leg, good power output can be achieved. For a mid-temperature n-type doped skutterudite material an efficiency of over 11% at a temperature difference of 600 °C could be achieved. Besides the improvement of thermoelectric materials, device optimization is a crucial factor for efficient heat-to-electric power conversion and one of the key challenges is how to create a large temperature across a thermoelectric generator especially in the case of a dilute incident heat flux. For the solar application of thermoelectrics we investigated the concept of large thermal heat flux concentration to optimize the operating temperature for highest solar thermoelectric generator efficiency. A solar-to-electric power conversion efficiency of ~5% could be demonstrated. Solar thermoelectric generators with a large thermal concentration which minimizes the amount of thermoelectric nanostrucutured bulk material shows great potential to enable cost-effective electrical power generation from the sun.

Chen, Gang; Kraemer, Daniel; Muto, Andrew; McEnaney, Kenneth; Feng, Hsien-Ping; Liu, Wei-Shu; Zhang, Qian; Yu, Bo; Ren, Zhifeng

2011-05-01

227

MHD Mode Conversion around a 2D Magnetic Null Point  

NASA Astrophysics Data System (ADS)

Mode conversion occurs when a wave passes through a region where the sound and Alfvén speeds are equal. At this point there is a resonance, which allows some of the incident wave to be converted into a different mode. We study this phenomenon in the vicinity of a two-dimensional, coronal null point. As a wave approaches the null it passes from low- to high-? plasma, allowing conversion to take place. We simulate this numerically by sending in a slow magnetoacoustic wave from the upper boundary; as this passes through the conversion layer a fast wave can clearly be seen propagating ahead. Numerical simulations combined with an analytical WKB investigation allow us to determine and track both the incident and converted waves throughout the domain.

McDougall, A. M. D.; Hood, A. W.

2009-02-01

228

Magnetic fusion energy and computers  

Microsoft Academic Search

The application of computers to magnetic fusion energy research is essential. In the last several years the use of computers in the numerical modeling of fusion systems has increased substantially. There are several categories of computer models used to study the physics of magnetically confined plasmas. A comparable number of types of models for engineering studies are also in use.

J. Killeen

1982-01-01

229

Planar High Energy Permanent Magnets.  

National Technical Information Service (NTIS)

The purpose of the program is to demonstrate the feasibility of fabricating cobalt-rare earth permanent magnets by the arc plasma spraying process. Property goals for spray-fabricated magnets consisted of a coercive force of 6000 oersteds and an energy pr...

M. C. Willson R. J. Janowiecki

1974-01-01

230

Ocean Thermal Energy Conversion and the Next Generation Fisheries  

Microsoft Academic Search

The world's fisheries are in decline and so are also the reservoirs of fossil fuels. OTEC (Ocean Thermal Energy Conversion) is a process that can harness vast amounts of renewable thermal energy from the ocean and convert it to electricity. OTEC prototypes of the order of 1 MW have been tested, and GW-size floating plants have been designed. The cost

Lars G. Golmen; Stephen M. Masutani; Kazuyuki Ouchi

231

Wind Energy Conversion Systems. A Unit of Instruction.  

ERIC Educational Resources Information Center

The number of secondary schools, colleges, and universities offering courses in wind energy machine construction, repair, and installation, continues to increase. It is the purpose of this unit to include the study of wind energy conversion systems (WECS) as an integral part of related vocational and technical curriculum materials. The unit's…

Greenwald, Martin

232

Wind Energy Conversion Systems. A Unit of Instruction.  

ERIC Educational Resources Information Center

|The number of secondary schools, colleges, and universities offering courses in wind energy machine construction, repair, and installation, continues to increase. It is the purpose of this unit to include the study of wind energy conversion systems (WECS) as an integral part of related vocational and technical curriculum materials. The unit's…

Greenwald, Martin

233

Cogeneration Technology Alternatives Study (Ctas). Volume 4: Energy Conversion Systems.  

National Technical Information Service (NTIS)

Industrial processes from the largest energy consuming sectors were used as a basis for matching a similar number of energy conversion systems that are considered as candidate which can be made available by the 1985 to 2000 time period. The sectors consid...

D. H. Brown H. E. Gerlaugh R. R. Priestley

1980-01-01

234

Nanostructured materials for advanced energy conversion and storage devices  

Microsoft Academic Search

New materials hold the key to fundamental advances in energy conversion and storage, both of which are vital in order to meet the challenge of global warming and the finite nature of fossil fuels. Nanomaterials in particular offer unique properties or combinations of properties as electrodes and electrolytes in a range of energy devices. This review describes some recent developments

Antonino Salvatore Aricò; Peter Bruce; Bruno Scrosati; Jean-Marie Tarascon; Walter van Schalkwijk

2005-01-01

235

Optimal hedging for flexible fuel energy conversion networks  

Microsoft Academic Search

We demonstrate an alternative approach for the hedging of flexible energy conversion networks appropriate for use in campus scale and municipal scale utilities with complex energy requirements, fuel sources, and operational flexibility. This new approach utilizes empirical modeling of price models for alternative commodity fuels coupled with a previously reported class of bilinear models for estimating the efficiency of complex

Jeffrey Kantor; Patrick Mousaw

2010-01-01

236

Ocean Thermal Energy Conversion (OTEC): Ocean Engineering Technology Development  

Microsoft Academic Search

Ocean Thermal Energy Conversion (OTEC) is the principal ocean energy source under development in the U.S. because of its potential, state of development, and availability and access of the resource to the U.S. The major features of OTEC are that the source is renewable with minimum impact on the environment and the constant availability of the resource enhances OTEC acceptability

J. Giannotti; J. Vadus

1981-01-01

237

Wind energy conversion systems using fuzzy sliding mode control  

Microsoft Academic Search

The paper describes a manner in which the energy-reliability optimization of wind energy conversion system's operation can be achieved by means of the fuzzy sliding mode control. An appropriate sliding surface has been found in the speed-power plane, which allows the operation more or less close to the optimal regimes characteristic. What is more, by torque controlling the generator, an

Qi Chen; LiangHai Chen; LinGao Wang

2011-01-01

238

Electric utility value analysis methodology for wind energy conversion systems  

Microsoft Academic Search

The methodology summarized in this report was developed in support of a study of the value of augmenting conventional electric energy generation with wind energy conversion systems (WECS). A major objective of the value analysis study is the creation of an analytical methodology to assess WECS installed in a utility's generation system. The pertinent measures of value include both the

L. R. Bush; C. K. Cretcher; T. H. Davey

1981-01-01

239

Heat exchanger development for Ocean Thermal Energy Conversion  

Microsoft Academic Search

Heat exchangers comprise one of the largest cost drivers for Ocean Thermal Energy Conversion (OTEC) systems. Reductions in fabrication costs and improvements in performance are critical to successfully commercialize sustainable energy power plants using this low (?20°C) ?T resource. Heat exchanger (HX) units should maximize heat transfer per unit area (U value) while minimizing pressure losses, corrosion and cost. Current

Michael P. Eldred; Joseph C. Van Ryzin; Steven Rizea; In Chieh Chen; Robert Loudon; N. John Nagurny; Scott Maurer; Eugene Jansen; Andrew Plumb; Michael R. Eller; Victor R. R. Brown

2011-01-01

240

Pin stack array for thermoacoustic energy conversion  

DOEpatents

A thermoacoustic stack for connecting two heat exchangers in a thermoacoustic energy converter provides a convex fluid-solid interface in a plane perpendicular to an axis for acoustic oscillation of fluid between the two heat exchangers. The convex surfaces increase the ratio of the fluid volume in the effective thermoacoustic volume that is displaced from the convex surface to the fluid volume that is adjacent the surface within which viscous energy losses occur. Increasing the volume ratio results in an increase in the ratio of transferred thermal energy to viscous energy losses, with a concomitant increase in operating efficiency of the thermoacoustic converter. The convex surfaces may be easily provided by a pin array having elements arranged parallel to the direction of acoustic oscillations and with effective radial dimensions much smaller than the thicknesses of the viscous energy loss and thermoacoustic energy transfer volumes.

Keolian, Robert M. (Monterey, CA); Swift, Gregory W. (Santa Fe, NM)

1995-01-01

241

Revisit ocean thermal energy conversion system  

Microsoft Academic Search

The earth, covered more than70.8% by the ocean, receives most of itsenergy from the sun. Solar energy istransmitted through the atmosphere andefficiently collected and stored in thesurface layer of the ocean, largely in thetropical zone. Some of the energy isre-emitted to the atmosphere to drive thehydrologic cycle and wind. The wind fieldreturns some of the energy to the ocean inthe

JOSEPH C. HUANG; HANS J. KROCK; STEPHEN K. ONEY

2003-01-01

242

Application of interval computation technique to fixed speed wind energy conversion system  

Microsoft Academic Search

Any wind energy conversion system (WECS) experiences uncertainty in wind velocity, tip-speed ratio, power co-efficient and stiffness of the wind turbine shaft. Also, the magnetizing inductance of the induction generator varies during self-excitation process. This makes the analysis and control of WECS, a difficult proposition. This paper presents an interval analysis based computation method for the calculation and analysis of

R. K. Thakur; V. Agarwal

2008-01-01

243

A Novel Control Scheme for Current-Source-Converter-Based PMSG Wind Energy Conversion Systems  

Microsoft Academic Search

A novel control scheme for permanent-magnet synchronous generator is proposed in this paper, where a current-source converter is employed as the bridge between the generator and the grid for high-power wind energy conversion systems. In these medium voltage (2.3-13.8 kV) level applications, current-source converters not only have inherent advantages, but also present some challenges for controller design due to the

Jingya Dai; Bin Wu

2009-01-01

244

Six-phase PMSG wind energy conversion system based on medium-voltage multilevel converter  

Microsoft Academic Search

A new power converter interface for permanent magnet synchronous generator (PMSG) based wind energy conversion systems (WECS) is presented in this paper. The converter stage is capable to stepup the low-voltage side of standard six-phase PMSG used in today’s WECS to a medium-voltage grid side. The proposed converter is an hybrid back-to-back topology composed of two series connected three-phase voltage

Mario J. Duran; Samir Kouro; Bin Wu; Emil Levi; Federico Barrero; Salvador Alepuz

2011-01-01

245

The maximum efficiency of the conversion of solar energy into wind energy  

Microsoft Academic Search

In the present paper, the Gordon and Zarmi model is applied for the conversion of solar energy into wind energy, in such a way that simple calculations lead to a universal result: The upper bound for the conversion efficiency of solar energy into wind energy equals 8.3%.

Alexis De Vos; G. Flater

1991-01-01

246

U.S. energy conversion research needs  

Microsoft Academic Search

Six energy systems, considered likely to be the major energy sources for the next 25 years, are analyzed with attention to weaknesses in their technology and to the R & D goals that should be pursued. The six systems are nuclear breeder systems, direct burning and carbonization of coal while in compliance with environmental protection controls, synthetic high-Btu (pipeline quality)

G. P. Cooper

1977-01-01

247

Material considerations involved in solar energy conversion  

Microsoft Academic Search

Recent investigations of the application of solar energy to electrical power generation which have proved encouraging in certain geographic locations in the United States are discussed. These encouraging findings have been due, in part, to the application of aerospace-related technology and systems engineering to critical elements of the solar energy system which have heretofore proven economically unrealistic. Results to date

R. L. Gervais; H. Taketani; H. W. Babel; G. F. Pittinato

1975-01-01

248

Glasses for solar energy conversion systems  

Microsoft Academic Search

Solar technologies are projected to increase tremendously over the next 10 years. Glasses are playing an important role as transparent materials of photovoltaic (PV) cells and concentrating solar power (CSP) systems. Glasses are materials of short energy payback time and environmental compatibility suitable for sustainable energy concepts. The paper reviews recent solar applications. Surface structuring and coating of glasses are

J. Deubener; G. Helsch; A. Moiseev; H. Bornhöft

2009-01-01

249

Compact magnetic electron energy analyzer  

Microsoft Academic Search

A compact magnetic energy analyzer designed for the measurement of electron energies in the range from 20 keV through 1.5 MeV is described. The simple device, based on the semicircular focusing principle, is constructed from a high induction permanent magnet enclosed in a soft iron case. The design and operation of the analyzer in pulsed electron beam devices are discussed.

R. F. Schneider; C. M. Luo; M. J. Rhee; J. R. Smith

1985-01-01

250

Primary Photosynthetic Energy Conversion in Bacterial Reaction Centers  

NASA Astrophysics Data System (ADS)

The development of human societies is strongly influenced by the available energetic resources. In a period where the limitations of conventional fossil energy carriers become as evident as the often uncontrollable dangers of nuclear energy, one has to reconsider regenerative energy resources. Here photovoltaic or photochemical use of solar energy is an important approach. Since the early days of evolution some two billion years ago, the dominant energetic input into the life system on earth occurs via the conversion of solar energy performed in photosynthetic organisms. The fossil energy carriers that we use and waste today have been produced by photosynthesis over millions of years. In the race for an extended and versatile use of solar energy, semiconductorbased photovoltaic devices have been developed. However, even after decades of intense engineering they cannot serve as a competitive alternative to fossil energy. Under these circumstances new alternatives are required. One line of scientific development may use the operational principles of photosynthesis since photosynthesis is still our main energy source. In this respect, we will present results on the basic concepts of energy conversion in photosynthetic bacteria, which could be used as a guideline to alternative light energy conversion systems.

Zinth, Wolfgang; Wachtveitl, J.

251

Energy Conversion and Storage Program. 1990 annual report  

SciTech Connect

The Energy Conversion and Storage Program applies chemistry and materials science principles to solve problems in (1) production of new synthetic fuels, (2) development of high-performance rechargeable batteries and fuel cells, (3) development of advanced thermochemical processes for energy conversion, (4) characterization of complex chemical processes, and (5) application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis. Electrochemistry research aims to develop advanced power systems for electric vehicle and stationary energy storage applications. Topics include identification of new electrochemical couples for advanced rechargeable batteries, improvements in battery and fuel-cell materials, and the establishment of engineering principles applicable to electrochemical energy storage and conversion. Chemical Applications research includes topics such as separations, catalysis, fuels, and chemical analyses. Included in this program area are projects to develop improved, energy-efficient methods for processing waste streams from synfuel plants and coal gasifiers. Other research projects seek to identify and characterize the constituents of liquid fuel-system streams and to devise energy-efficient means for their separation. Materials Applications research includes the evaluation of the properties of advanced materials, as well as the development of novel preparation techniques. For example, the use of advanced techniques, such as sputtering and laser ablation, are being used to produce high-temperature superconducting films.

Cairns, E.J.

1992-03-01

252

Carbon nanomaterials for advanced energy conversion and storage.  

PubMed

It is estimated that the world will need to double its energy supply by 2050. Nanotechnology has opened up new frontiers in materials science and engineering to meet this challenge by creating new materials, particularly carbon nanomaterials, for efficient energy conversion and storage. Comparing to conventional energy materials, carbon nanomaterials possess unique size-/surface-dependent (e.g., morphological, electrical, optical, and mechanical) properties useful for enhancing the energy-conversion and storage performances. During the past 25 years or so, therefore, considerable efforts have been made to utilize the unique properties of carbon nanomaterials, including fullerenes, carbon nanotubes, and graphene, as energy materials, and tremendous progress has been achieved in developing high-performance energy conversion (e.g., solar cells and fuel cells) and storage (e.g., supercapacitors and batteries) devices. This article reviews progress in the research and development of carbon nanomaterials during the past twenty years or so for advanced energy conversion and storage, along with some discussions on challenges and perspectives in this exciting field. PMID:22383334

Dai, Liming; Chang, Dong Wook; Baek, Jong-Beom; Lu, Wen

2012-03-02

253

Solar Thermal Energy Conversion Program: Summary Report.  

National Technical Information Service (NTIS)

Project summaries are given for contracts pertaining to the central receiver power plant, 5 Mwth solar thermal test facility, total energy systems, distributed collector systems, hybrid systems, research and development, and program application and suppor...

1976-01-01

254

Polymer Based Nanocomposites for Solar Energy Conversion  

SciTech Connect

Organic semiconductor-based photovoltaic devices offer the promise of low cost photovoltaic technology that can be manufactured via large-scale, roll-to-roll printing techniques. Existing organic photovoltaic devices are currently limited to solar power conversion efficiencies of 3?5%. This is because of poor overlap between the absorption spectrum of the organic chromophores and the solar spectrum, non-ideal band alignment between the donor and acceptor species, and low charge carrier mobilities. To address these issues, we are investigating the development of dendrimeric organic semiconductors that are readily synthesized with high purity. They also benefit from optoelectronic properties, such as band gap and band positions, which can be easily tuned by substituting different chemical groups into the molecule. Additionally, we are developing nanostructured oxide/conjugated polymer composite photovoltaics. These composites take advantage of the high electron mobilities attainable in oxide semiconductors and can be fabricated using low-temperature solution-based growth techniques. Here, we discuss the synthesis and preliminary device results of these novel materials and composites.

Shaheen, S.; Olson, D.; White, M.; Mitchell, W.; Miedaner, A.; Curtis, C.; Rumbles, G.; Gregg, B.; Ginley, D.

2005-01-01

255

Solar Energy Conversion – Natural to Artificial  

Microsoft Academic Search

\\u000a Photosynthesis is the process by which energy of light is converted into chemical energy by plants, algae and photosynthetic\\u000a bacteria. For this, highly specialized pigment–proteins have evolved that capture the light and transform the short-lived\\u000a excited states of pigment molecules into a stable transmembrane potential. By close scrutiny of organization and processes\\u000a of the photosynthetic pigment systems a number of

Villy Sundstrom

256

Vibration-to-electric energy conversion  

Microsoft Academic Search

A system is proposed to convert ambient mechanical vibration into electrical energy for use in powering autonomous low-power electronic systems. The energy is transduced through the use of a variable capacitor, which has been designed with MEMS (microelectromechanical systems) tech- nology. A low-power controller IC has been fabricated in a 0 6µm CMOS pro- cess and has been tested and

Scott Meninger; Jose Oscar Mur-Miranda; Rajeevan Amirtharajah; Anantha Chandrakasan; Jeffrey Lang

1999-01-01

257

Superconducting energy storage magnet  

SciTech Connect

A superconducting magnet is described comprising: (a) a coil of turns of conductor including at least a superconducting composite material, the turns of conductor lying substantially on a surface which defines a frustum of a cone having a wide end and a narrow end, such that the outward pressure as a result of current flowing through the conductor in the magnetic field produced by the magnet at the wide end of the coil is less than the outward pressure at the narrow end of the coil; and (b) means for supporting the coil of conductors in the magnet to carry the outward pressure imposed on the coil by the interaction of the current flowing in the conductor with the magnetic field, wherein the turns of the conductor in the coil have outwardly bowed ripples therein and inner portions between the ripples with the ripple pattern extending around the circumferential periphery of the magnet structure, and wherein the means for supporting includes support struts extending from a surrounding support mass to engage the conductor at the inwardly bowed portions of the rippled conductor forming the coil.

Boom, R.W.; Eyssa, Y.M.; Abdelsalam, M.K.; Xianrui Huang.

1993-08-17

258

On the electrokinetic energy conversion in liquid mixtures  

NASA Astrophysics Data System (ADS)

The dependence of the maximum efficiency of the electrokinetic energy conversion, (eta)max, on the composition of liquid mixtures is studied. Experiments on streaming potential and electroosmosis were conducted with Pyrex glass plugs using aqueous mixtures of different alcohols as permeants in order to investigate the influence of the properties of the permeant on the energy conversion process. A strong dependence is found between the quantities (eta)max and D sq/lambda mu, where mu is the absolute viscosity, lambda is the specific conductance of the liquid permeant, and D equals epsilon/epsilon sub 0, where epsilon is the absolute dielectric constant.

Hidalgo-Alvarez, R.; Gonzalez-Caballero, F.; Pardo, G.

1983-03-01

259

Research on energy storage for solar thermal conversion. Final report  

Microsoft Academic Search

The study is an evaluation of thermal energy storage (TES) for solar thermal energy conversion to electric power. Major emphasis has been placed on determining the relative merits of latent, sensible, and hybrid latent-sensible storage systems. The thermal energy storage systems evaluated are compatible with 10 MW\\/sub e\\/ and 100 MW\\/sub e\\/ steam power plants with TES delivery temperature ranges

J. L. Clayton; W. D. Moudy; F. D. Stooksberry

1978-01-01

260

Direct Energy Conversion Nano-hybrid Fuel  

SciTech Connect

Most of the exothermic nuclear reactions transfer the mass defect or binding and surplus energy into kinetic energy of the resulting particles. These particles are traveling through material lattices, interacting by ionization and nuclear collisions. Placing an assembly of conductive-insulating layers in the path of such radiation, the ionization energy is transformed into charge accumulation by polarization. The result is a super-capacitor charged by the moving particles and discharged electrically. Another more promising solution is to use bi-material nanoparticles organized such as to act like a serial connection and add the voltage. A spherical symmetry fission products source coated in several nano-layers is desired for such structures. The system may operate as dry or liquid-immersed battery, removing the fission products from the fissile material. There is a tremendous advantage over the current heat flow based thermal stabilization system allowing a power density up to 1000 times higher. (author)

Popa-Simil, Liviu [R and D, LAVM LLC., Los Alamos, NM, 87544 (United States)

2008-07-01

261

Photosynthetic energy conversion: natural and artificial.  

PubMed

Photosystem II (PSII) is the water splitting enzyme of photosynthesis. Its appearance during evolution dramatically changed the chemical composition of our planet and set in motion an unprecedented explosion in biological activity. Powered by sunlight, PSII supplies biology with the 'hydrogen' needed to convert carbon dioxide into organic molecules. The questions now are can we continue to exploit this photosynthetic process through increased use of biomass as an energy source and, more importantly, can we address the energy/CO2 problem by developing new photochemical technologies which mimic the natural system? (Critical review, 82 references). PMID:19088973

Barber, James

2008-11-10

262

Energy storage and conversion technique and apparatus  

Microsoft Academic Search

The kinetic energy of the wind is converted into compressed air which is stored, in a system which maintains a predetermined output pressure, for use in driving a turbine coupled to an electrical power generator. The gas storage system includes two pair of serially connected storage tanks with the first tank in each pair receiving compressed air from wind driven

Germain

1977-01-01

263

The NASA program in Space Energy Conversion Research and Technology  

NASA Astrophysics Data System (ADS)

The considered Space Energy Conversion Program seeks advancement of basic understanding of energy conversion processes and improvement of component technologies, always in the context of the entire power subsystem. Activities in the program are divided among the traditional disciplines of photovoltaics, electrochemistry, thermoelectrics, and power systems management and distribution. In addition, a broad range of cross-disciplinary explorations of potentially revolutionary new concepts are supported under the advanced energetics program area. Solar cell research and technology are discussed, taking into account the enhancement of the efficiency of Si solar cells, GaAs liquid phase epitaxy and vapor phase epitaxy solar cells, the use of GaAs solar cells in concentrator systems, and the efficiency of a three junction cascade solar cell. Attention is also given to blanket and array technology, the alkali metal thermoelectric converter, a fuel cell/electrolysis system, and thermal to electric conversion.

Mullin, J. P.; Flood, D. J.; Ambrus, J. H.; Hudson, W. R.

264

Proceedings of the 25th intersociety energy conversion engineering conference  

SciTech Connect

This book contains the proceedings of the 25th Intersociety Energy Conversion Engineering Conference. Volume 5 is organized under the following headings: Photovoltaics I, Photovoltaics II, Geothermal power, Thermochemical conversion of biomass, Energy from waste and biomass, Solar thermal systems for environmental applications, Solar thermal low temperature systems and components, Solar thermal high temperature systems and components, Wind systems, Space power sterling technology Stirling cooler developments, Stirling solar terrestrial I, Stirling solar terrestrial II, Stirling engine generator sets, Stirling models and simulations, Stirling engine analysis, Stirling models and simulations, Stirling engine analysis, Stirling engine loss understanding, Novel engine concepts, Coal conversion and utilization, Power cycles, MHD water propulsion I, Underwater vehicle powerplants - performance, MHD underwater propulsion II, Nuclear power, Update of advanced nuclear power reactor concepts.

Nelson, P.A.; Schertz, W.W.; Till, R.H.

1990-01-01

265

Preliminary energy sector assessments of Jamaica. Volume III: renewable energy. Part IV: energy conversion from waste  

SciTech Connect

The study considers the feasibility of energy conversion from wastes. Specifically, the study analyzes the potential for energy recovery from urban wastes in Jamaica, with the Kingston area serving as a case study, and assesses the feasibility of building a prototype demonstration unit for energy recovery from solid wastes at the University of the West Indies (UWI)-Mona Campus. Steam-generating waterwall combustion, refuse-derived fuel systems, pyrolysis, anaerobic biological conversion (biogas), and gas recovery from landfills are discussed as alternative systems for energy recovery from urban wastes.

Not Available

1980-01-01

266

Light-energy conversion in engineered microorganisms.  

PubMed

Increasing interest in renewable resources by the energy and chemical industries has spurred new technologies both to capture solar energy and to develop biologically derived chemical feedstocks and fuels. Advances in molecular biology and metabolic engineering have provided new insights and techniques for increasing biomass and biohydrogen production, and recent efforts in synthetic biology have demonstrated that complex regulatory and metabolic networks can be designed and engineered in microorganisms. Here, we explore how light-driven processes may be incorporated into nonphotosynthetic microbes to boost metabolic capacity for the production of industrial and fine chemicals. Progress towards the introduction of light-driven proton pumping or anoxygenic photosynthesis into Escherichia coli to increase the efficiency of metabolically-engineered biosynthetic pathways is highlighted. PMID:18951642

Johnson, Ethan T; Schmidt-Dannert, Claudia

2008-10-23

267

Pulsed power conversion with inductive storage. [PULSAR compressed magnetic flux  

Microsoft Academic Search

The PULSAR compressed magnetic flux, pulse power generator system has applications as a topping stage in commercial power generation. A plasma armature mode of operation is described which could be powered by an inertially confined fusion reactor. The paper summarizes the development of a plasma armature and experimental results from its application in a PULSAR generator which utilizes a 0.5

E. C. Cnare; M. Cowan; T. P. Wright; W. K. Tucker

1977-01-01

268

Efficient Energy Conversion of the 14 MeV Neutrons in DT Inertial Confinement Fusion  

NASA Astrophysics Data System (ADS)

In DT fusion 80 % of the energy released goes into 14 MeV neutrons, and only the remaining 20 % into charged particles. Unlike the charged particles, the uncharged neutrons cannot be confined by a magnetic field, and for this reason cannot be used for a direct conversion into electric energy. Instead, the neutrons have to be slowed down in some medium, heating this medium to a temperature of less than 103 K, with the heat removed from this medium to drive a turbo-generator. This conversion of nuclear into electric energy has a Carnot efficiency of about 30 %. For the 80 % of the energy released into neutrons, the efficiency is therefore no more than 24 %. While this low conversion efficiency cannot be overcome in magnetic confinement concepts, it can be overcome in inertial confinement concepts, by surrounding the inertial confinement fusion target with a sufficiently thick layer of liquid hydrogen and a thin outer layer of boron, to create a hot plasma fire ball. The hydrogen layer must be chosen just thick and dense enough to be heated by the neutrons to 100,000 K. The thusly generated, fully ionized, and rapidly expanding fire ball can drive a pulsed magnetohydrodynamic generator at an almost 100 % Carnot efficiency, or possibly be used to generate hydrocarbons.

Winterberg, F.

2013-02-01

269

Photovoltaic and photoelectrochemical conversion of solar energy.  

PubMed

The Sun provides approximately 100,000 terawatts to the Earth which is about 10000 times more than the present rate of the world's present energy consumption. Photovoltaic cells are being increasingly used to tap into this huge resource and will play a key role in future sustainable energy systems. So far, solid-state junction devices, usually made of silicon, crystalline or amorphous, and profiting from the experience and material availability resulting from the semiconductor industry, have dominated photovoltaic solar energy converters. These systems have by now attained a mature state serving a rapidly growing market, expected to rise to 300 GW by 2030. However, the cost of photovoltaic electricity production is still too high to be competitive with nuclear or fossil energy. Thin film photovoltaic cells made of CuInSe or CdTe are being increasingly employed along with amorphous silicon. The recently discovered cells based on mesoscopic inorganic or organic semiconductors commonly referred to as 'bulk' junctions due to their three-dimensional structure are very attractive alternatives which offer the prospect of very low cost fabrication. The prototype of this family of devices is the dye-sensitized solar cell (DSC), which accomplishes the optical absorption and the charge separation processes by the association of a sensitizer as light-absorbing material with a wide band gap semiconductor of mesoporous or nanocrystalline morphology. Research is booming also in the area of third generation photovoltaic cells where multi-junction devices and a recent breakthrough concerning multiple carrier generation in quantum dot absorbers offer promising perspectives. PMID:17272237

Grätzel, Michael

2007-04-15

270

Ocean Thermal Energy Conversion Program Management Plan  

Microsoft Academic Search

The Office of the Associate Laboratory Director for Energy and Environmental Technology has established the OTEC Program Management Office to be responsible for the ANL-assigned tasks of the OTEC Program under DOE's Chicago Operations and Regional Office (DOE\\/CORO). The ANL OTEC Program Management Plan is essentially a management-by-objective plan. The principal objective of the program is to provide lead technical

1980-01-01

271

Wind energy conversion systems control using TS fuzzy modeling  

Microsoft Academic Search

The paper investigates the wind energy conversion systems (WECS) control problem. To deal with the intrinsic nonlinear behavior of WECS, a T-S fuzzy model is proposed. The method assumes that the wind speed is unmeasurable. Then an H8 output feedback controller is designed by taking into account directly wind speed as perturbation. The design conditions are given in linear matrix

M. Chadli; A. El Hajjaji

2010-01-01

272

Solar Program Assessment: Environmental Factors - Ocean Thermal Energy Conversion.  

ERIC Educational Resources Information Center

This report presents the environmental problems which may arise with the further development of Ocean Thermal Energy Conversion, one of the eight Federally-funded solar technologies. To provide a background for this environmental analysis, the history and basic concepts of the technology are reviewed, as are its economic and resource requirements.…

Energy Research and Development Administration, Washington, DC. Div. of Solar Energy.

273

Technical and economic assessment of geopressured energy recovery and conversion  

Microsoft Academic Search

Potentially productive geopressured sediments have been identified in more than twenty specific onshore fairways in Louisiana and Texas. A total of at least 232 trillion cubic feet (TCF) of dissolved methane and 367 x 10¹⁵ Btu (367 quads) of thermal energy may be contained in the water within the sandstones in these formations. As a result of conversion plant efficiencies,

T. R. Fick; J. W. Hankin; A. Renton; R. K. Swanson

1980-01-01

274

Energiutvinning ur kaellsorterade foerpackningsfraktioner. (Energy conversion of source separated packaging).  

National Technical Information Service (NTIS)

The basic idea of this project is to study the possibilities to use source separated combustible material for energy conversion in conventional solid fuel boilers (i.e. not municipal waste incineration plants). The project has been carried out in three ph...

O. Blidholm S. E. Wiklund A. C. Bauer

1997-01-01

275

Wind energy conversion system simulator using variable speed induction motor  

Microsoft Academic Search

The conventional synchronous generator in wind energy conversion system are now getting replaced by variable speed induction generator to extract maximum power with wide range of wind speed limit. The design and performance of such system are required a simplified digital simulator, especially for development of optimal control solutions. The proposed work is to make a prototype of an variable

S. W. Mohod; M. V. Aware

2010-01-01

276

Quantitative evaluation of Ocean Thermal Energy Conversion (OTEC): Executive briefing  

NASA Astrophysics Data System (ADS)

The results of an independent quantitative evaluation of Ocean Thermal Energy Conversion (OTEC) for central station applications are summarized. A central station power plant located in the Gulf of Mexico and delivering power to the mainland United States was emphasized. The evaluation of OTEC is based on three important issues: resource availability, technical feasibility, and cost.

Gritton, E. C.; Pei, R. Y.; Hess, R. W.

1980-08-01

277

A study of water electrolysis with photovoltaic solar energy conversion  

Microsoft Academic Search

The performance of the hydrogen production system consisting of the photovoltaic array and the water electrolysis unit is studied. The results of the calculation are compared with available experimental data and the performance of a hydrogen production plant by means of photovoltaic solar energy conversion is determined for two typical locations. A method for the estimation of the power matching

C. Carpetis

1982-01-01

278

Unified energy conversion, power systems and power electronics lab  

Microsoft Academic Search

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

Seungwon An; Swakshar Ray; Thomas W. Gedra

2002-01-01

279

Probabilistic production costing of diesel-wind energy conversion systems  

Microsoft Academic Search

This paper describes the development of a general probabilistic model of a diesel-wind energy conversion system (DWECS) composed of several diesel units, several wind turbines (wind farm), and battery storage feeding a load. The model allows the simulation of a diesel system with a wind farm of different wind turbine types considering system stability, and outages due to hardware failure

Sami H. Karaki; Riad B. Chedid; Rania Ramadan

2000-01-01

280

Limiting efficiencies for photovoltaic energy conversion in multigap systems  

Microsoft Academic Search

Multigap systems are better matched to the sun's spectrum than single gap systems and are, therefore, more efficient as photovoltaic converters. This paper reviews the different thermodynamic approaches used in the past for computing the limiting efficiency for the conversion of solar energy into work. Within this thermodynamic context, the limit ranges from 85.4% to 95.0% depending on the assumptions

Antonio Martí; Gerardo L. Araújo

1996-01-01

281

Chemical conversion surfaces for solar-energy applications  

Microsoft Academic Search

An attempt is made to determine which coatings and substrate combinations might hold the greatest promise for chemical conversion coating of substrate materials. The following substrate materials are investigated: aluminum, copper, brass, zinc, cadmium, aluminum\\/zinc alloys, nickel, iron, and stainless steel. One of the major impediments to the utilization of solar energy is the initial cost of the systems. One

S. W. Moore; J. S. Clements; W. R. Doty

1983-01-01

282

Commercialization analysis of large wind energy conversion systems. Final report  

Microsoft Academic Search

The framework is described that can be used to evaluate potential new federal incentives to facilitate the market acceptance of utility-scale wind energy conversion systems. The insights gained from utilizing this framework to evaluate a variety of hypothetical federal incentives are discussed. The heart of the evaluation framework is an explicit representation of the decisions made by utility purchasers, suppliers,

D. W. Boyd; O. E. Buckley; S. M. Haas

1980-01-01

283

Experiments to Determine the Efficiency of Various Energy Conversions.  

ERIC Educational Resources Information Center

Described are experiments used in the "Physical Science and Man" course at Hartley CAE which enable determinations of efficiencies of two energy conversion processes, namely, electricity into heat and burning gas to produce heat. Activities for comparing the processes are suggested. (DS)

Curtis, D.; Goodwin, R. D.

1980-01-01

284

Open cycle ocean thermal energy conversion system structure  

Microsoft Academic Search

An open cycle, ocean thermal energy conversion system is described, comprising: an axial flow turbine having a substantially vertical rotatable shaft about which at least one axial row of radial blades is disposed, an annular steam inlet structure through which motive steam is supplied to said turbine blades, and a steam outlet structure through which motive steam is exhausted after

Wittig

1980-01-01

285

Biomass energy conversion and utilization in the developing countries  

Microsoft Academic Search

Information on the conversion and use of biomass energy is summarized and pictorially illustrated in this manual. Section I presents the basic principles of anaerobic digestion and shows how to design and construct biogas plants. Topics covered include: the digestion process; carbon-nitrogen ratio; temperature dependency; Indian- and Chinese-type and horizontal digesters; alternative designs; manure production; gas production and use; cooking;

1985-01-01

286

Solar Program Assessment: Environmental Factors - Ocean Thermal Energy Conversion.  

ERIC Educational Resources Information Center

|This report presents the environmental problems which may arise with the further development of Ocean Thermal Energy Conversion, one of the eight Federally-funded solar technologies. To provide a background for this environmental analysis, the history and basic concepts of the technology are reviewed, as are its economic and resource…

Energy Research and Development Administration, Washington, DC. Div. of Solar Energy.

287

Compact magnetic energy storage module  

DOEpatents

A superconducting compact magnetic energy storage module in which a plurality of superconducting toroids, each having a toroidally wound superconducting winding inside a poloidally wound superconducting winding, are stacked so that the flow of electricity in each toroidally wound superconducting winding is in a direction opposite from the direction of electrical flow in other contiguous superconducting toroids. This allows for minimal magnetic pollution outside of the module. 4 figures.

Prueitt, M.L.

1994-12-20

288

Compact magnetic energy storage module  

DOEpatents

A superconducting compact magnetic energy storage module in which a plurality of superconducting toroids, each having a toroidally wound superconducting winding inside a poloidally wound superconducting winding, are stacked so that the flow of electricity in each toroidally wound superconducting winding is in a direction opposite from the direction of electrical flow in other contiguous superconducting toroids. This allows for minimal magnetic pollution outside of the module.

Prueitt, Melvin L. (Los Alamos, NM)

1994-01-01

289

Magnetic Reconnection During Flux Conversion in a Driven Spheromak  

SciTech Connect

During buildup of a spheromak by helicity injection, magnetic reconnection converts toroidal flux into poloidal flux. This physics is explored in the resistive magnetohydrodynamic code, NIMROD [C.R. Sovinec, A.H. Glasser, T.A. Gianakon, D.C. Barnes, R.A. Nebel, S.E. Kruger, D.D. Schnack, S.J. Plimpton, A. Tarditi, and M.S. Chu, J. Comp. Phys., 195, 355-386 (2004)], which reveals negative current sheets with {lambda} = {mu}{sub 0}j {center_dot} B/B{sup 2}reversed relative to the applied current. The simulated event duration is consistent with magnetic diffusion on the sheet thickness and is accompanied by cathode voltage spikes and poloidal field increases similar to those seen in the Sustained Spheromak Physics Experiment, SSPX [E. B. Hooper, L. D. Pearlstein, and R. H. Bulmer, Nucl. Fusion 39, 863 (1999)]. All magnetic fieldlines are open during reconnection and their trajectories are very sensitive to their starting points, resulting in chaos. The current sheets are most intense inside the separatrix near the X-point of the mean-field spheromak, suggesting that the reconnection occurs near fieldlines which are closed in the azimuthal average.

Hooper, E B; Kopriva, T A; Cohen, B I; Hill, D N; McLean, H S; Wood, R D; Woodruff, S; Sovinec, C R

2005-06-07

290

Toroidal accelerator rotor platforms for wind energy conversion  

Microsoft Academic Search

A toroidal accelerator rotor platform (TARP) design for wind energy conversion systems (WECS) application is described and analyzed for performance and economic viability using both experimental results and analytical approaches. As an obstruction type flow concentrator and accelerator, a TARP generates low-pressure high-kinetic-wind-energy regions at its rotor disk sites. Since rotor performance is enhanced by flow augmentation, the calculated power

A. L. Weisbrich

1977-01-01

291

Photochemical solar energy conversion. An assessment of scientific accomplishments  

Microsoft Academic Search

Research on photochemical solar energy conversion has grown exponentially. Basic sciences have benefited most from this research. The tenet of this article is that solar energy research has appreciably contributed to the ongoing renaissance of colloid chemistry and to the development of ever-more-sophisticated models for light-sensitized distance-controlled electron transfers. The need for compartmentalizing components of the photosynthetic apparatus-sensitizers: electron donors,

Janos H. Fendler

1985-01-01

292

Economic analysis of small wind-energy conversion systems  

Microsoft Academic Search

The financial costs of obtaining electricity from small wind-energy conversion systems are calculated and compared with the cost of electricity from traditional utility companies. A 3 kW rated wind electric system for residential use is examined. The amount of energy from this system is estimated by using a computer-operated simulation model which incorporates wind speeds, residential electricity demands and parameters

Barry N. Haack

1982-01-01

293

Energy considerations in vector magnetization models  

SciTech Connect

Scalar magnetization model energy calculations, which are useful in calculating energy losses in open magnetization processes, are extended here to vector models. The energy loss is calculated as the difference between the energy input to the magnetic medium and the change in energy stored in the locally reversible component of the total magnetization. It is shown that under rotating magnetizing processes, the energy loss decreases as the material is saturated. For smaller rotating fields in anisotropic media, the magnetization lies between the applied field and the easy axis and the energy loss is not constant with rotation even if the magnitude of the field is constant. {copyright} 2001 American Institute of Physics.

DellaTorre, Edward; Reimers, Ann

2001-06-01

294

SOLID STATE ENERGY CONVERSION ALLIANCE DELPHI SOFC  

SciTech Connect

The objective of Phase I under this project is to develop a 5 kW Solid Oxide Fuel Cell power system for a range of fuels and applications. During Phase I, the following will be accomplished: Develop and demonstrate technology transfer efforts on a 5 kW stationary distributed power generation system that incorporates steam reforming of natural gas with piped-in water (Demonstration System A); and Initiate development of a 5 kW system for later mass-market automotive auxiliary power unit application, which will incorporate Catalytic Partial Oxidation (CPO) reforming of gasoline, with anode exhaust gas injected into an ultra-lean burn internal combustion engine. This technical progress report covers work performed by Delphi from July through December 2002 under Department of Energy Cooperative Agreement DE-FC-02NT41246 for the 5 kW mass-market automotive (gasoline) auxiliary power unit. This report highlights technical results of the work performed under the following tasks for the automotive 5 kW system: Task 1--System Design and Integration; Task 2--Solid Oxide Fuel Cell Stack Developments; Task 3--Reformer Developments; Task 4--Development of Balance of Plant (BOP) Components; Task 5--Manufacturing Development (Privately Funded); Task 6--System Fabrication; and Task 7--System Testing.

Steven Shaffer; Sean Kelly; Subhasish Mukerjee; David Schumann; H. Skip Mieney

2003-06-09

295

New elements in wind energy conversion siting  

SciTech Connect

The purpose of this investigation is to quantify a number of site characteristics for site selection for wind powered generators. It is assumed that the wind powered generators will be integrated in a utility grid which is in addition supplied from conventional power sources and does not have energy storage capabilities. The objective is to enable the selection of the available sites in such a manner as to maximize the desirable benefits from the installation of the wind powered generators, i.e. either installed capacity displacement or fuel savings. The hourly wind speeds from three sites for the year 1975 are utilized to demonstrate the quantification of the parameters based in part on the notions of reliability analysis. It is shown that individual sites differ significantly from each other and that a ''composite'' site can be constructed using dispersed installations in such a manner as to obtain the desirable characteristics. It is assumed that the electric power distribution grid under consideration is of sufficient extent so that several wind regimes can be found.

Lois, L.

1980-12-01

296

SPS energy conversion and power management workshop. Final report  

SciTech Connect

In 1977 a four year study, the concept Development and Evaluation Program, was initiated by the US Department of Energy and the National Aeronautics and Space Administration. As part of this program, a series of peer reviews were carried out within the technical community to allow available information on SPS to be sifted, examined and, if need be, challenged. The SPS Energy Conversion and Power Management Workshop, held in Huntsville, Alabama, February 5 to 7, 1980, was one of these reviews. The results of studies in this particular field were presented to an audience of carefully selected scientists and engineers. This first report summarizes the results of that peer review. It is not intended to be an exhaustive treatment of the subject. Rather, it is designed to look at the SPS energy conversion and power management options in breadth, not depth, to try to foresee any troublesome and/or potentially unresolvable problems and to identify the most promising areas for future research and development. Topics include photovoltaic conversion, solar thermal conversion, and electric power distribution processing and power management. (WHK)

Not Available

1980-06-01

297

Photon-Axion Conversion in Intergalactic Magnetic Fields and Cosmological Consequences  

Microsoft Academic Search

Photon-axion conversion induced by intergalactic magnetic fields causes an apparent dimming of distant sources, notably of cosmic distance indicators such as supernovae of type Ia (SNe Ia). We review the impact of this mechanism on the luminosity-redshift relation of SNe Ia, on the dispersion of quasar spectra, and on the spectrum of the cosmic microwave background. The original idea of

Alessandro Mirizzi; Georg G. Raffelt; Pasquale D. Serpico

2008-01-01

298

Effect of Low Magnetic Fields on the Catalysed Parahydrogen Conversion Rate over Certain Rare Earths.  

National Technical Information Service (NTIS)

The purpose of the communication is to report a change in rate of the parahydrogen conversion if the catalyst is placed in a magnetic field of a few oersteds. The change is a decrease of several per cent, and it has been observed over Pr2O3, Nd2O3, Sm2O3 ...

P. W. Selwood

1970-01-01

299

Thermal stress analysis of IGBT modules in VSCs for PMSG in large offshore Wind Energy Conversion Systems  

Microsoft Academic Search

Components for offshore wind farms are required to be highly reliable due to harsh environmental conditions and poor accessibility for maintenance. Direct-Drive Permanent Magnet Synchronous Generator (PMSG) connected with back to back converters represents an attractive solution for large offshore Wind Energy Conversion Systems (WECSs). Large direct driven Wind Turbine Generators (WTGs) operate at lower speed compared to conventional geared

Riccardo Pittini; Salvatore D'Arco; Magnar Hernes; Astrid Petterteig

2011-01-01

300

LQR with integral action applied to a wind energy conversion system based on doubly fed induction generator  

Microsoft Academic Search

This paper presents the design of a Linear Quadratic Regulator (LQR) with Integral action (LQRI) applied to a wind energy conversion system (WECS) based on doubly fed induction generator (DFIG). The controller is used to achieve speed regulation for maximum power extraction from the wind turbine, DC bus voltage regulation, to make the machine draw its magnetizing current only from

Bachir Kedjar; Kamal Al-Haddad

2011-01-01

301

Maximum electrical energy production of a variable speed Wind Energy Conversion System  

Microsoft Academic Search

This paper proposes a control strategy for Wind Energy Conversion Systems (WECSs) aiming in both maximum power harvesting from the wind turbine and minimum power loss of the electrical generator. Thus, maximum efficiency along the whole wind energy conversion process is achieved and additionally expansion of the exploitable wind speed region towards the lower-speed range is accomplished. A squirrel cage

A. Mesemanolis; C. Mademlis; I. Kioskeridis

2012-01-01

302

Magnetic fusion energy and computers  

SciTech Connect

The application of computers to magnetic fusion energy research is essential. In the last several years the use of computers in the numerical modeling of fusion systems has increased substantially. There are several categories of computer models used to study the physics of magnetically confined plasmas. A comparable number of types of models for engineering studies are also in use. To meet the needs of the fusion program, the National Magnetic Fusion Energy Computer Center has been established at the Lawrence Livermore National Laboratory. A large central computing facility is linked to smaller computer centers at each of the major MFE laboratories by a communication network. In addition to providing cost effective computing services, the NMFECC environment stimulates collaboration and the sharing of computer codes among the various fusion research groups.

Killeen, J.

1982-01-01

303

Magnetohydrodynamic energy conversion by using convexly divergent channel  

SciTech Connect

We describe a magnetohydrodynamic (MHD) electrical power generator equipped with a convexly divergent channel, as determined through shock-tunnel-based experiments. The quality of MHD power-generating plasma and the energy conversion efficiency in the convexly divergent channel are compared with those from previous linearly divergent channel. The divergence enhancement in the channel upstream is effective for suppressing an excessive increase in static pressure, whereby notably high isentropic efficiency is achieved.

Murakami, Tomoyuki; Okuno, Yoshihiro [Department of Energy Sciences, Tokyo Institute of Technology, 4259-G3-38 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan)

2009-12-21

304

Comparative study of turbines for wave energy conversion  

Microsoft Academic Search

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

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

2001-01-01

305

Photosynthetic energy conversion in the diatom Phaeodactylum tricornutum  

Microsoft Academic Search

Isothermal microcalorimetry can be used to investigate the photosynthetic energy conversion of autotrophic organisms. In this\\u000a study, for the first time a diatom alga was used to compare the calorimetrically measured heat flux with measurements of the\\u000a photosynthetic performance by oxygen evolution and pulse-amplitude modulated fluorescence. The presented experimental setup\\u000a proved suitable to compare calorimetric data with those of conventional

Steffen Oroszi; Torsten Jakob; Christian Wilhelm; Hauke Harms; Thomas Maskow

2011-01-01

306

Ocean thermal energy conversion: Historical highlights, status, and forecast  

Microsoft Academic Search

In 1881, d'Arsonval conceived the closed-Rankine-cycle ocean thermal energy conversion (OTEC) system in which a working fluid is vaporized by heat exchange with cold water drawn from a 700-1200 m depth. In 1930, Claude demonstrated an open-cycle process in Cuba. Surface water was flash-vaporized at 3 kPa to drive a turbine directly (no secondary working fluid) and then was condensed

G. L. Dugger; W. H. Avery; E. J. Francis; D. Richards

1983-01-01

307

Plasmonic Nanoparticles and Their Suspensions for Solar Energy Conversion  

NASA Astrophysics Data System (ADS)

Plasmon resonance in nanoscale metallic structures has shown its ability to concentrate electromagnetic energy into sub-wavelength volumes. Metal nanostructures exhibit a high extinction coefficient in the visible and near infrared spectrum due to their large absorption and scattering cross sections corresponding to their surface plasmon resonance. Hence, they can serve as an attractive candidate for solar energy conversion. Recent papers have showed that dielectric core/metallic shell nanoparticles yielded a plasmon resonance wavelength tunable from visible to infrared by changing the ratio of core radius to the total radius. Therefore it is interesting to develop a dispersion of core-shell multifunctional nanoparticles capable of dynamically changing their volume ratio and thus their spectral radiative properties. Nanoparticle suspensions (nanofluids) are known to offer a variety of benefits for thermal transport and energy conversion. Nanofluids have been proven to increase the efficiency of the photo-thermal energy conversion process in direct solar absorption collectors (DAC). Combining these two cutting-edge technologies enables the use of core-shell nanoparticles to control the spectral and radiative properties of plasmonic nanofluids in order to efficiently harvest and convert solar energy. Plasmonic nanofluids that have strong energy concentrating capacity and spectral selectivity can be used in many high-temperature energy systems where radiative heat transport is essential. In this thesis, the surface plasmon resonance effect and the wavelength tuning ranges for different metallic shell nanoparticles are investigated, the solar-weighted efficiencies of corresponding core-shell nanoparticle suspensions are explored, and a quantitative study of core-shell nanoparticle suspensions in a DAC system is provided. Using core-shell nanoparticle dispersions, it is possible to create efficient spectral solar absorption fluids and design materials for applications which require variable spectral absorption or scattering.

Lv, Wei

308

Simulation and demonstration of magnetohydrodynamic energy conversion in a high-temperature inert gas  

NASA Astrophysics Data System (ADS)

The present paper describes high-density magnetohydrodynamic (MHD) energy conversion in a high-temperature seed-free argon plasma, for which a quasi-three-dimensional numerical simulation and a single-pulse shock-tunnel-based demonstration are conducted. The numerical model simulates the two-dimensional profiles of both the electron and the heavy-particle system of the supersonic argon plasma flow, of which the total inflow temperature is 8000 K. The MHD power-generating experiment clarifies the relationship between the plasma quality and the energy conversion efficiency as functions of the total inflow temperature (7600-9600 K) and the applied magnetic flux density (up to 4.0 T). The increase in the total inflow temperature from 7600 to 9400 K and the application of magnetic flux with density of 0.5-1.2 T change the plasma state; unstable behavior accompanied by an inhomogeneous structure is transformed to a homogeneous and stable state, which results in the significant improvement of the power generation performance. Even in low-density magnetic flux, the attained generator performance is comparable or superior to previous results obtained using a conventional low-temperature seeded gas.

Murakami, Tomoyuki; Okuno, Yoshihiro

2009-03-01

309

Superconducting magnets in high energy physics  

SciTech Connect

The applications of superconducting magnets in high energy physics in the last ten years have made feasible developments which are vital to high energy research. These developments include high magnetic field, large volume detectors, such as bubble chambers, required for effective resolution of high energy particle trajectories, particle beam transport magnets, and superconducting focusing and bending magnets for the very high energy accelerators and storage rings needed to pursue the study of interactions between elementary particles. The acceptance of superconductivity as a proven technology in high energy physics was reinforced by the recognition that the existing large accelerators using copper-iron magnets had reached practical limits in terms of magnetic field intensity, cost, space, and energy usage, and that large-volume, high-field, copper-iron magnets were not economically feasible. Some of the superconducting magnets and associated systems being used in and being developed for high energy physics are described.

Prodell, A G

1978-01-01

310

Solar energy-conversion processes in organic solar cells  

NASA Astrophysics Data System (ADS)

Organic semiconducting materials have demonstrated attractive light-absorption and photocurrent-generation functions due to their delocalized ? electrons as well as intra-molecular and inter-molecular charge separation processes. On the other hand, organic semiconducting materials have easy property tuning, are mechanically flexible, and have large-area thin film formation properties. As a result, organic materials have become potential candidates in solar energy applications. This article will review critical energy-conversion processes in organic solar cells with the focus on singlet and triplet photovoltaic responses.

Xu, Zhihua; Zang, Huidong; Hu, Bin

2008-09-01

311

Synergistic Energy Conversion Processes Using Nuclear Energy and Fossil Fuels  

Microsoft Academic Search

This paper reviews the methods of producing energy carriers, such as electricity, hydrocarbons and hydrogen, by utilizing both nuclear energy and fossil fuels synergistically. There are many possibilities of new, innovative, synergistic processes, which combine chemical and nuclear systems for efficient, clean and economical production of energy carriers. Besides the individual processes by each energy to produce the energy carriers,

Masao Hori

2008-01-01

312

Detection of low-energy conversion electrons and location of isomeric states  

SciTech Connect

The detection of conversion electrons of short-lived isotopes at ISOCELE has been extended to very low-energy: a special tape-transport system has been built which allows the slowing down of the incoming radioactive ions and the acceleration of the electrons detected on photographic film in a flat magnetic spectrograph. Results have been acquired for the decay of mercury with A = 185, 186, 187, 189, 191, and of platinum with A = 184, and 186. As examples the location of isomeric states deduced from our measurements are given to illustrate the power of high-resolution electron detection.

Kilcher; Sauvage, J.; Bourgeois, C.; Le Blanc, F.; Oms, J.; Roussiere, B.; Munsch, J.; Obert, J.; Caruette, A.; Ferro, A.; and others

1987-12-10

313

High-density magnetohydrodynamic energy conversion in a high-temperature inert gas  

SciTech Connect

We describe high-density magnetohydrodynamic (MHD) energy conversion in a high-temperature seed-free argon plasma, for which a compact disk-shaped Hall-type radial-flow MHD electrical power generator is used. The state of the MHD power-generating plasma changes with increasing total inflow temperature from 8200 to 9400 K; unstable behavior accompanied by the appearance of fine structures is transformed to a homogeneous and stable state. The attained enthalpy extraction efficiency is comparable to previous results using a conventional seeded gas. Furthermore, a high power output density is achieved even in relatively low-density magnetic flux.

Murakami, Tomoyuki; Okuno, Yoshihiro [Department of Energy Sciences, Tokyo Institute of Technology, 4259-G3-38 Nagatsuta, Midori-ku, Yokohama 226-8502 (Japan)

2008-07-28

314

Non-contact frequency-up-conversion energy harvester for durable & broad-band automotive TPMS application  

Microsoft Academic Search

This paper presents a nonlinear energy harvester that can be operated in a wide frequency range of tens of Hz, as a potential power supply for tire pressure monitoring systems (TPMS). Frequency up-conversion is achieved by a two-stage oscillator structure. The non-contact magnetic repulsive driving mechanism eliminates mechanical collision during operation, thereby improving efficiency and endurance. A miniature energy harvester

Q. C. Tang; X. Y. Xia; X. X. Li

2012-01-01

315

Renewable energy from the sea - organic Rankine Cycle using ocean thermal energy conversion  

Microsoft Academic Search

Rankine cycles using refrigerant- and benzene-series fluids as working fluids in converting low-grade energy from renewable energy resources such as solar energy and ocean thermal energy were investigated in this study. The main purpose is to verify the feasibility of utilizing ocean energy (i.e., ocean thermal energy conversion, OTEC) which can also be combined with solar energy in an organic

S. K. Wang; T. C. Hung

2010-01-01

316

Cogeneration from Waste Energy Streams Four Energy Conversion Systems Described  

Microsoft Academic Search

In times of rapid growth in the costs of energy of all types, renewed interest comes for cogeneration. Specifically, the recovery of waste energy has become economical and the potential for growth of cogeneration systems to utilize waste heat is high. Cogeneration systems for bottoming cycles and waste energy recovery from process streams are described. The nature of the energy

James Palmer

1981-01-01

317

Photon-Axion Conversion in Intergalactic Magnetic Fields and Cosmological Consequences  

Microsoft Academic Search

Photon-axion conversion induced by intergalactic magnetic fields causes an apparent dimming of distant sources, notably of\\u000a cosmic distance indicators such as supernovae of type Ia (SNe Ia). We review the impact of this mechanism on the luminosity-redshift\\u000a relation of SNe Ia, on the dispersion of quasar spectra, and on the spectrum of the cosmic microwave background. The original\\u000a idea of

Alessandro Mirizzi; Georg G. Raffelt; Pasquale D. Serpico

318

A micropower CMOS, direct-conversion, VLF receiver chip for magnetic-field wireless applications  

Microsoft Academic Search

A micropower CMOS, direct-conversion very low frequency (VLF) receiver is described for receiving low-level magnetic fields from resonant sensors. The single-chip, phase locked loop (PLL)-synthesized receiver covers a frequency range of 10-82 kHz and provides both analog and 9-b digital baseband I and Q outputs. Digital I and Q outputs are accumulated in a companion digital chip which provides baseband

David M. Binkley; James M. Rochelle; Brian K. Swann; Lloyd G. Clonts; Rhonda N. Goble

1998-01-01

319

Beryllium pressure vessels for creep tests in magnetic fusion energy  

Microsoft Academic Search

Beryllium has interesting applications in magnetic fusion experimental machines and future power-producing fusion reactors. Chief among the properties of beryllium that make these applications possible is its ability to act as a neutron multiplier, thereby increasing the tritium breeding ability of energy conversion blankets. Another property, the behavior of beryllium in a 14-MeV neutron environment, has not been fully investigated,

Neef

1990-01-01

320

Giant magnetoelectric effect in magnet-cymbal-solenoid current-to-voltage conversion device  

NASA Astrophysics Data System (ADS)

A giant magnetoelectric (ME) effect is reported in a current-to-voltage (I-to-V) conversion device formed by sandwiching a PZT piezoelectric cymbal transducer between an NdFeB magnet and a Fe-core solenoid. The observed ME effect results from the direct coupling of the electromagnetically induced attractive-repellent force effect in the magnet-solenoid assembly with the amplified piezoelectric effect in the cymbal transducer. The device exhibits a colossal I-to-V conversion factor (S) of 27.1 V/A with a giant ME coefficient (?V) of 1.24 V/Oe at a low resonance frequency of 2.33 kHz, besides a large S of 0.74 V/A with a high ?V of 34 mV/Oe in the nonresonance frequency range of 40 Hz-1 kHz. A physical model based on the combination of electromagnetomechanics in the magnet-solenoid assembly and amplified piezoelectricity in the cymbal transducer is present to explain the observed ME effect and the resulting I-to-V conversion in the device.

Zeng, Min; Or, Siu Wing; Chan, Helen Lai Wa

2010-04-01

321

Magnetic Energy Production by Turbulence in Binary Neutron Star Mergers  

NASA Astrophysics Data System (ADS)

The simultaneous detection of electromagnetic and gravitational wave emission from merging neutron star binaries would greatly aid in their discovery and interpretation. By studying turbulent amplification of magnetic fields in local high-resolution simulations of neutron star merger conditions, we demonstrate that magnetar-level (gsim 1016 G) fields are present throughout the merger duration. We find that the small-scale turbulent dynamo converts 60% of the randomized kinetic energy into magnetic fields on a merger timescale. Since turbulent magnetic energy dissipates through reconnection events that accelerate relativistic electrons, turbulence may facilitate the conversion of orbital kinetic energy into radiation. If 10-4 of the ~1053 erg of orbital kinetic available gets processed through reconnection and creates radiation in the 15-150 keV band, then the fluence at 200 Mpc would be 10-7 erg cm-2, potentially rendering most merging neutron stars in the advanced LIGO and Virgo detection volumes detectable by Swift BAT.

Zrake, Jonathan; MacFadyen, Andrew I.

2013-06-01

322

Electrical System for Home Conversion and Storage of Solar Energy.  

PubMed

Energy storage has long been a problem in connection with home utilization of solar energy. A solution which utilizes solar semiconductor cells for conversion to d-c power is proposed. The d-c power is used to drive an alternator which is connected directly across the residential power lines. Thus a-c power is delivered to the power lines when a surplus of power is available in the home and is used in other parts of the power distribution system. At latitude 42 degrees N there is 3 times more yearly energy recoverable than is used by an average residence on the basis of a 10-by-10-m collection area. At the present state of technical development the cost of such a large-area semiconductor solar cell would be prohibitive. PMID:17732892

Giacoletto, L J

1959-10-01

323

Artificial photosynthesis: biomimetic approaches to solar energy conversion and storage.  

PubMed

Using sun as the energy source, natural photosynthesis carries out a number of useful reactions such as oxidation of water to molecular oxygen and fixation of CO(2) in the form of sugars. These are achieved through a series of light-induced multi-electron-transfer reactions involving chlorophylls in a special arrangement and several other species including specific enzymes. Artificial photosynthesis attempts to reconstruct these key processes in simpler model systems such that solar energy and abundant natural resources can be used to generate high energy fuels and restrict the amount of CO(2) in the atmosphere. Details of few model catalytic systems that lead to clean oxidation of water to H(2) and O(2), photoelectrochemical solar cells for the direct conversion of sunlight to electricity, solar cells for total decomposition of water and catalytic systems for fixation of CO(2) to fuels such as methanol and methane are reviewed here. PMID:20439158

Kalyanasundaram, K; Graetzel, M

2010-05-01

324

Fluidized-bed energy technology for biomass conversion  

SciTech Connect

Fluidized bed technology was experimentally evaluated for the combustion and gasification of cotton gin waste. The isothermal bed temperatures in the reactors could be maintained below the ash fusion point of the waste. Raw stripper harvested cotton gin trash could be metered directly into the fluidized-bed reactors indicating that little feed preparation is required. H and CO were the primary products of gasification, and approximately 3200-400 Btu of gas were produced per lb of cotton gin waste. These techniques offer the potential of providing small-scale energy conversion systems for use on farms.

LePori, W.A.; Anthony, R.G.; Lalk, T.R.; Craig, J.; Groves, J.

1980-01-01

325

Heat transfer research for ocean thermal energy conversion  

NASA Astrophysics Data System (ADS)

In this lecture an overview of the heat- and mass-transfer phenomena of importance in ocean thermal energy conversion (OTEC) is presented with particular emphasis on open-cycle OTEC systems. Also included is a short historical review of OTEC developments in the past century and a comparison of open- and closed-cycle thermodynamics. Finally, results of system analyses, showing the effect of plant size on cost and the near-term potential of using OTEC for combined power production and desalination systems are briefly discussed.

Kreith, F.; Bharathan, D.

1987-03-01

326

Carbon dioxide release from ocean thermal energy conversion (OTEC) cycles  

SciTech Connect

This paper presents the results of recent measurements of CO{sub 2} release from an open-cycle ocean thermal energy conversion (OTEC) experiment. Based on these data, the rate of short-term CO{sub 2} release from future open-cycle OTEC plants is projected to be 15 to 25 times smaller than that from fossil-fueled electric power plants. OTEC system that incorporate subsurface mixed discharge are expected to result in no long-term release. OTEC plants can significantly reduce CO{sub 2} emissions when substituted for fossil-fueled power generation. 12 refs., 4 figs., 3 tabs.

Green, H.J. (Solar Energy Research Inst., Golden, CO (USA)); Guenther, P.R. (Scripps Institution of Oceanography, La Jolla, CA (USA))

1990-09-01

327

Colloidal semiconductors as photocatalysts for solar energy conversion  

SciTech Connect

Considerable attention has been drawn in recent years to develop ultrafine semiconductor particles which exhibit excellent photocatalytic properties. Size quantization effects, nonlinear optical properties and enhanced photoredox properties make quantized colloidal semiconductors potentially useful in the design of photoelectrochemical systems. Photochemical and photophysical processes that directly influence the photocatalytic properties of the semiconductor colloids and the factors that limit the charge transfer at the semiconductor/electrolyte interface are discussed here. Applications of semiconductor particulate systems in the conversion and storage of solar energy are also described.

Kamat, P.V.; Dimitrijevic, N.M. (Notre Dame Radiation Laboratory, IN (USA))

1990-01-01

328

An investigation of the effect of a magnetic field on the phosphate conversion coating formed on magnesium alloy  

NASA Astrophysics Data System (ADS)

In this paper, the influence of the magnetic field on the phosphate conversion coating formed on magnesium alloy has been studied by scanning ion selective electrode technique (SIET), X-rays phase-contrast radiography, scanning electron microscopy (SEM) and atomic force microscopy (AFM). The results show that the superposition of a magnetic field during the phosphate conversion coating process can promote the generation of small hydrogen gas bubbles and accelerate their desorption. In addition, irrespective of the microstructure of the AZ91D magnesium alloy, it was found that the Mg2+ cations were distributed comparatively uniformly. A uniform smooth phosphate conversion coating could be obtained by immersion in the treatment solution when a magnetic field was applied perpendicular to the magnesium alloy. It may be expected to use magnetic field to control the formation of phosphate conversion coating on magnesium alloy.

Zhao, Ming; Li, Jianguo; He, Guangping; Xie, Honglan; Fu, Yanan

2013-10-01

329

High Temperature Fusion Reactor Cooling Using Brayton Cycle Based Partial Energy Conversion  

NASA Astrophysics Data System (ADS)

For some future space power systems using high temperature nuclear heat sources most of the output energy will be used in other than electrical form, and only a fraction of the total thermal energy generated will need to be converted to electrical work. The paper describes the conceptual design of such a ``partial energy conversion'' system, consisting of a high temperature fusion reactor operating in series with a high temperature radiator and in parallel with dual closed cycle gas turbine (CCGT) power systems, also referred to as closed Brayton cycle (CBC) systems, which are supplied with a fraction of the reactor thermal energy for conversion to electric power. Most of the fusion reactor's output is in the form of charged plasma which is expanded through a magnetic nozzle of the interplanetary propulsion system. Reactor heat energy is ducted to the high temperature series radiator utilizing the electric power generated to drive a helium gas circulation fan. In addition to discussing the thermodynamic aspects of the system design the authors include a brief overview of the gas turbine and fan rotor-dynamics and proposed bearing support technology along with performance characteristics of the three phase AC electric power generator and fan drive motor.

Juhasz, Albert J.; Sawicki, Jerzy T.

2004-02-01

330

Investigation on energy conversion technology using biochemical reaction elements, 2  

NASA Astrophysics Data System (ADS)

For measures taken for resource/energy and environmental issues, a study is made on utilization of microbial biochemical reaction. As a reaction system using chemical energy, cited is production of petroleum substitution substances and food/feed by CO2 fixation using hydrogen energy and hydrogen bacteria. As to photo energy utilization, regarded as promising are CO2 fixation using photo energy and microalgae, and production of hydrogen and useful carbon compound using photosynthetic organisms. As living organism/electric energy interconversion, cited is the culture of chemoautotrophic bacteria which fix CO2 using electric energy. For enhancing its conversion efficiency, it is important to develop a technology of gene manipulation of the bacteria and a system to use functional biochemical elements adaptable to the electrode reaction. With regard to utilization of the microorganism metabolic function, the paper presents emission of soluble nitrogen in the hydrosphere into the atmosphere using denitrifying bacteria, removal of phosphorus, reduction in environmental pollution caused by heavy metal dilute solutions, and recovery as resources, etc.

1994-03-01

331

Energy flow principles of IGBT inverters in wind energy conversion systems  

Microsoft Academic Search

Two energy flow principles, defined as the voltage magnitude control principle (MCP) and the voltage phase control principle (PCP), are presented in this paper for wind energy conversion (WEC) grid-connected inverter systems using insulated-gate bipolar transistors (IGBTs). The MCP is for the WEC system to produce a correct energy flow from the wind turbine to the grid by adequate voltage

Hong Huang; Liuchen Chang

2000-01-01

332

PRELIMINARY ENVIRONMENTAL ASSESSMENT OF ENERGY CONVERSION PROCESSES FOR AGRICULTURAL AND FOREST PRODUCT RESIDUES. VOLUME 1  

EPA Science Inventory

A preliminary assessment was made of the environmental impacts of several types of conversion processes for producing energy or fuels from agricultural and forestry residues. Fifteen examples were selected to represent various combinations of agricultural residues and conversion ...

333

Organic electronics on fibers for energy conversion applications  

NASA Astrophysics Data System (ADS)

Currently, there is great demand for pollution-free and renewable sources of electricity. Solar cells are particularly attractive from the standpoint of sunlight abundance. However, truly widespread adoption of solar cells is impeded by the high cost and poor scalability of existing technologies. For example, while 53,000 mi2 of 10% efficient solar cell modules would be required to supply the current U.S. energy demand, only about 50 mi2 have been installed worldwide. Organic semiconductors potentially offer a route to realizing low-cost solar cell modules, but currently suffer from low conversion efficiency. For organic-based solar cells to become commercially viable, further research is required to improve device performance, develop scalable manufacturing methods, and reduce installation costs via, for example, novel device form factors. This thesis makes several contributions to the field of organic solar cells, including the replacement of costly and brittle indium tin oxide (ITO) electrodes by inexpensive and malleable, thin metal films, and the application of external dielectric coatings to improve power conversion efficiency. Furthermore, we show that devices with non-planar geometries (e.g. organic solar cells deposited onto long fibers) can have higher efficiencies than conventional planar devices. Building on these results, we demonstrate novel fiber-based organic light emitting devices (OLEDs) that offer substantially improved color quality and manufacturability as a next-generation solid-state lighting technology. An intriguing possibility afforded by the fiber-based device architectures is the ability to integrate energy conversion and lighting functionalities with textiles, a mature, commodity-scale technology.

O'Connor, Brendan T.

334

Magnetic diffusion and flare energy buildup  

Microsoft Academic Search

Photospheric motion shears or twists solar magnetic fields to increase magnetic energy in the corona, because this process may change a current-free state of a coronal field to force-free states which carry electric current. This paper analyzes both linear and nonlinear two-dimensional force-free magnetic field models and derives relations of magnetic energy buildup with photospheric velocity field. When realistic data

S. T. Wu; C. L. Yin; W.-H. Yang

1992-01-01

335

Magnetic diffusion and flare energy buildup  

Microsoft Academic Search

Photospheric motion shears or twists solar magnetic fields to increase magnetic energy in the corona, because this process may change a current-free state of a coronal field to force-free states which carry electric current. This paper analyzes both linear and nonlinear 2D force-free magnetic field models and derives relations of magnetic energy buildup with photospheric velocity field. When realistic data

S. T. Wu; C. L. Yin; W.-H. Yang

1992-01-01

336

Flexible ZnO-cellulose nanocomposite for multisource energy conversion.  

PubMed

Materials with the ability to harness multiple sources of energy from the ambient environment could lead to new types of energy-harvesting systems. It is demonstrated that nanocomposite films consisting of zinc oxide nanostructures embedded in a common paper matrix can be directly used as energy-conversion devices to transform mechanical and thermal energies to electric power. These mechanically robust and flexible devices can be fabricated over large areas and are capable of producing an output voltage and power up to 80 mV and 50 nW cm(-2) , respectively. Furthermore, it is shown that by integrating a certain number of devices (in series and parallel) the output voltage and the concomitant output power can be significantly increased. Also, the output voltage and power can be enhanced by scaling the size of the device. This multisource energy-harvesting system based on ZnO nanostructures embedded in a flexible paper matrix provides a simplified and cost-effective platform for capturing trace amounts of energy for practical applications. PMID:21626690

Kumar, Ashavani; Gullapalli, Hemtej; Balakrishnan, Kaushik; Botello-Mendez, Andres; Vajtai, Robert; Terrones, Mauricio; Ajayan, Pulickel M

2011-05-31

337

Naval facility energy conversion plants as resource recovery system components  

NASA Astrophysics Data System (ADS)

This interim report addresses concepts for recovering energy from solid waste by using Naval facilities steam plants as principle building blocks of candidate solid waste/resource recovery systems at Navy installations. The major conclusions of this portion of the project are: although it is technically feasible to adapt Navy energy conversion systems to fire Waste Derived Fuels (WDF) in one or more of its forms, the optimal form selected should be a site-specific total system; near- to intermediate-term programs should probably continue to give first consideration to waterwall incinerators and to the cofiring of solid WDF in coal-capable plants; package incinerators and conversions of oil burning plants to fire a fluff form of solid waste fuel may be the options with the greatest potential for the intermediate term because waterwalls would be uneconomical in many small plants and because the majority of medium-sized oil-burning plants will not be converted to burn coal; and pyrolytic processes to produce gaseous and liquid fuels have not been sufficiently developed as yet to be specified for commerical operation.

Capps, A. G.

1980-01-01

338

Plasmadynamics and ionization kinetics of thermionic energy conversion  

SciTech Connect

To reduce the plasma arc-drop, thermionic energy conversion is studied with both analytical and numerical tools. Simplifications are made in both the plasmadynamic and ionization-recombination theories. These are applied to a scheme proposed presently using laser irradiation to enhance the ionization kinetics of the thermionic plasma and thereby reduce the arc-drop. It is also predicted that it is possible to generate the required laser light from a thermionic-type cesium plasma. The analysis takes advantage of theoretical simplifications derived for the ionization-recombination kinetics. It is shown that large laser ionization enhancements can occur and that collisional cesium recombination lasing is expected. To complement the kinetic theory, a numerical method is developed to solve the thermionic plasma dynamics. To combine the analysis of ionization-recombination kinetics with the plasma dynamics of thermionic conversion, a finite difference computer program is constructed. It is capable of solving for both unsteady and steady thermionic converter behavior including possible laser ionization enhancement or atomic recombination lasing. A proposal to improve thermionic converter performance using laser radiation is considered. In this proposed scheme, laser radiation impinging on a thermionic plasma enhances the ionization process thereby raising the plasma density and reducing the plasma arc-drop. A source for such radiation may possibly be a cesium recombination laser operating in a different thermionic converter. The possibility of this being an energy efficient process is discussed. (WHK)

Lawless, J.L. Jr.; Lam, S.H.

1982-02-01

339

Energy transfer and photochemistry in biomimetic solar conversion  

NASA Astrophysics Data System (ADS)

The theoretically predicted orientation dependence of electronic energy transfer was tested in a completely defined, three dimensional array of chromophores. Steady state and time resolved fluorescence measurements demonstrate unambiquously that singlet energy transfer is orientation dependent. Quantitative analysis yields the orientation of the transition dipole moment for the first excited state of chlorophyll. Long range electron transfer was observed from an encapsulated chromophore excited singlet state to electron acceptors in solution. A rigidly connected donor/acceptor pair was designed and synthesized for studies of electron transfer mechanisms. An ultrasensitive apparatus was constructed and tested to measure magnetic field effects on luminescent recombination in amorphous Si.

Boxer, S. G.

1984-08-01

340

Selective blacks for enhanced photothermal solar energy conversion  

NASA Astrophysics Data System (ADS)

The optical and physical requirements of selective surfaces for maximum absorption of solar thermal energy are reviewed, along with processes to fabricate the selective coatings. Noting that the solar energy which reaches the ground is usually in wavelengths of 0.3-2 microns, the desired qualities of coatings are listed as stability of performance, good adherence to the substructure, ease of application, low emissivity above two microns, and economical fabrication. Selective surfaces comprise absorber-reflector tandems, which allow or reflect IR passage, multilayer interference stacks, which involve successive deposition of metallic coatings, and controlled surface morphology, which entails either geometric irregularities, Mie scattering films, corrugated surfaces, or wire mesh surfaces. Preparation can be by electrodeposition, chemical conversion, spray pyrolysis, paint coatings, vacuum deposition, and chemical vapor deposition (CVD), which is stressed as offering the most attractive option for economical large scale coating of solar selective surfaces.

Agarwal, R. C.; Pillai, P. K. C.

341

ECUT (Energy Conversion and Utilization Technologies) program: Biocatalysis Project  

NASA Astrophysics Data System (ADS)

Fiscal year 1987 research activities and accomplishments for the Biocatalysis Project of the U.S. Department of Energy, Energy Conversion and Utilization Technologies (ECUT) Division are presented. The project's technical activities were organized into three work elements. The Molecular Modeling and Applied Genetics work element includes modeling and simulation studies to verify a dynamic model of the enzyme carboxypeptidase; plasmid stabilization by chromosomal integration; growth and stability characteristics of plasmid-containing cells; and determination of optional production parameters for hyper-production of polyphenol oxidase. The Bioprocess Engineering work element supports efforts in novel bioreactor concepts that are likely to lead to substantially higher levels of reactor productivity, product yields, and lower separation energetics. The Bioprocess Design and Assessment work element attempts to develop procedures (via user-friendly computer software) for assessing the economics and energetics of a given biocatalyst process.

1988-03-01

342

Photochemical solar energy conversion. An assessment of scientific accomplishments  

SciTech Connect

Research on photochemical solar energy conversion has grown exponentially. Basic sciences have benefited most from this research. The tenet of this article is that solar energy research has appreciably contributed to the ongoing renaissance of colloid chemistry and to the development of ever-more-sophisticated models for light-sensitized distance-controlled electron transfers. The need for compartmentalizing components of the photosynthetic apparatus-sensitizers: electron donors, acceptors, and relays; and catalysts - has focused attention to microheterogeneous systems. Micelles, monolayers, organized multilayers, vesicles, polymerized vesicles, and dispersed colloidal semiconductors are used as molecular organizers in artifical photosynthesis. Properties and potentials of these systems have been summarized. Emphasis is placed on insights gained through photochemical investigations. Electron-transfer studies in covalently linked porphyrin-quinone, carotenoid polyene-porphyrin-quinone model compounds, and proteins are summarized.

Fendler, J.H.

1985-01-01

343

Silicon nanowires for biosensing, energy storage, and conversion.  

PubMed

Semiconducting silicon nanowires (SiNWs) represent one of the most interesting research directions in nanoscience and nanotechnology, with capabilities of realizing structural and functional complexity through rational design and synthesis. The exquisite control of chemical composition, structure, morphology, doping, and assembly of SiNWs, in both individual and array format, as well as incorporation with other materials, offers a nanoscale building block with unique electronic, optoelectronic, and catalytic properties, thus allowing for a variety of exciting opportunities in the fields of life sciences and renewable energy. This review provides a brief summary of SiNW research in the past decade, from the SiNW synthesis by both the top-down approaches and the bottom-up approaches, to several important biological and energy applications including biomolecule sensing, interfacing with cells and tissues, lithium-ion batteries, solar cells, and photoelectrochemical conversion. PMID:23828226

Wang, Yanli; Wang, Tianyu; Da, Peimei; Xu, Ming; Wu, Hao; Zheng, Gengfeng

2013-07-05

344

Economic analysis of small wind-energy conversion systems  

NASA Astrophysics Data System (ADS)

A computer simulation was developed for evaluating the economics of small wind energy conversion systems (SWECS). Input parameters consisted of initial capital investment, maintenance and operating costs, the cost of electricity from other sources, and the yield of electricity. Capital costs comprised the generator, tower, necessity for an inverter and/or storage batteries, and installation, in addition to interest on loans. Wind data recorded every three hours for one year in Detroit, MI was employed with a 0.16 power coefficient to extrapolate up to hub height as an example, along with 10 yr of use variances. A maximum return on investment was found to reside in using all the energy produced on site, rather than selling power to the utility. It is concluded that, based on a microeconomic analysis, SWECS are economically viable at present only where electric rates are inordinately high, such as in remote regions or on islands.

Haack, B. N.

1982-05-01

345

Physlets Tour 5: Conversion from Kinetic Energy to Thermal Energy  

NSDL National Science Digital Library

A heavy ball with an initial kinetic energy of 4000 J is trapped inside a box with rigid walls containing a cylinder constructed of small lightweight spheres. The vertical bar on to the right of each frame shows the kinetic energy of the ball. To the right are 80 small objects representing a solid that will be crushed and vaporized through impact with the disk.

Christian, Wolfgang; Belloni, Mario

2006-01-13

346

Experimental and Analytical Studies on Pyroelectric Waste Heat Energy Conversion  

NASA Astrophysics Data System (ADS)

This study is concerned with direct conversion of thermal energy into electrical energy by subjecting pyroelectric materials to the Olsen cycle. The Olsen cycle consists of two isoelectric field and two isothermal process on the electric displacement versus electric field diagram. The energy and power generation capabilities of copolymer poly(vinylidene fluoridetrifluorethylene) [P(VDF-TrFE)] films and lead lanthanum zirconate titanate (PLZT) ceramics were evaluated by executing the Olsen cycle via so-called "stamping experiments" and "dipping experiments". The stamping experiments consisted of alternatively pressing a pyroelectric material in thermal contact with hot and cold aluminum blocks under specified electric fields. It was performed to assess the pyroelectric energy conversion performance using heat conduction. The largest energy density generated in the stamping experiments was 155 J/L/cycle with 60/40 P(VDF-TrFE) thin film at 0.066 Hz between 25 and 110°C and electric fields cycled between 20 and 35 MV/m. This energy density exceeded the 130 J/L/cycle achieved by our previous prototypical device using oscillatory laminar convective heat transfer. However, the performance was limited by poor thermal contact between the aluminum blocks and pyroelectric material and also by excessive leakage current inherent to P(VDF-TrFE) at high temperatures and/or large electric fields. On the other hand, dipping experiments consisted of successively immersing a pyroelectric material into isothermal hot and cold thermal reservoirs at different temperatures while simultaneously cycling the electric fields. It was performed on relaxor ferroelectric x/65/35 PLZT ceramics with x between 5 and 10 mol.%. The operating temperature, applied electric field, sample thickness, cycle frequency, and electrode material were systematically varied to explore their respective effects on the energy and power densities produced. A maximum energy density of 1014 J/L/cycle was obtained with a 190?m thick 7/65/35 PLZT sample at 0.0256 Hz at temperatures between 30 and 200°C and electric field from 0.2 to 7.0 MV/m. To the best of our knowledge, this energy density is the largest achieved among pyroelectric single crystals, ceramics, and polymers using the Olsen cycle. Meanwhile, a maximum power density of 55.3 ± 8.0 W/L obtained with a 190?m thick 9.5/65/35 PLZT sample at 0.125 Hz. Additionally, the temperature-dependent dielectric behavior of PLZT ceramics were characterized. The polarization transition temperature of lanthanum-doped x /65/35 PLZT ceramics decreased from 240 to 10°C for increasing lanthanum dopant concentration x from 5 to 10 mol.%. This establishes that the different compositions should be operated at different temperatures for maximum pyroelectric energy conversion. Finally, a physical thermo-electrical model for estimating the energy harvested by ferroelectric relaxors was further validated against experimental data for a wide range of electric fields and temperatures.

Lee, Felix

347

Magnetic fusion energy materials technology program  

Microsoft Academic Search

The objectives of the magnetic fusion energy (MFE) materials technology program are to solve the materials problems of the fusion energy division of ORNL and to meet needs of the national MFE program, directed by the ERDA Division of Magnetic Fusion Energy (DMFE). The principal areas of work include radiation effects, compatibility studies, materials studies related to the plasma-materials interaction,

J. L. Scott

1977-01-01

348

Functional Nanostructures for Magnetic and Energy Application  

NASA Astrophysics Data System (ADS)

Functional nanostructures serve as the basic building blocks for nanodevices and significant efforts have been devoted to their morphology control and properties optimization. In present study, four functional nanostructures, i.e., FePt/B4C multilayer composite film, particle (FePt)/matrix (B4C) monolayer composite film, Ga-doped ZnO nanowire arrays, and CdSe nanotube arrays are designed, synthesized and characterized in detail, in which the first two are expected to be prominent candidates for ultrahigh-density magnetic storage media while the later two have potential applications in solar energy conversion. FePt/B4C multilayer thin films are deposited on silicon substrates using magnetron sputtering with different B4C layer thickness. Experimental results suggest that the B4C layers effectively serve as spacers to separate the FePt layers, making the multilayer configuration stable even after film annealing at elevated temperatures. On the other hand, B and C are found to be incorporated into the FePt layer, which is responsible for the FePt grain growth confinement and grain separation, and eventually affects the properties of the composite film. Based on the experimental results of multilayer composite film, particle (FePt)/matrix (B4C) monolayer composite thin films on Si substrate are synthesized, in which a record coercivity of 2200 Oe is achieved compared to similar system. The size uniformity of the FePt nanoparticles, the well-defined particle-particle separation, together with the good magnetic property and high temperature thermal stability of the overall composite film, make it a very promising candidate for the ultrahigh density magnetic storage media. Semiconductor based one-dimensional nanostructures are investigated as promising building blocks for solar energy conversion devices. Two aspects are explored, aiming at increasing the energy conversion efficiency, i.e., facilitating electron transport and enhancing photon absorbing. In the first case, large area Ga-doped ZnO nanowire arrays are grown on transparent conducting substrate. Experimental results reveal the well-aligned array morphology and the uniform Ga concentration in these nanowires. In particular, direct I-V measurements performed on single nanowire-on-ITO substrate disclose its Ohmic contact with the conducting substrate and the significant conductivity improvement compared to undoped ZnO nanowire, In the second case, a novel synthesis strategy for nanotube arrays is developed and CdSe is used for demonstration, which material possessing more appropriate band gap as effective light harvester compared to that of materials for existing semiconductor nanotube arrays. The controllable tube wall thickness that can be increased until continuous CdSe porous network is obtained. The experimental results suggest a nanotube array formation mechanism that can be generally applied to a wide range of materials.

Zhou, Minjie

349

Wind energy conversion based on seven-level cascaded H-bridge inverter using LabVIEW FPGA  

Microsoft Academic Search

In this paper, an isolated wind energy conversion system (WECS) based on the cascaded H-bridge multilevel inverter (CHBMLI) topology employing a permanent magnet synchronous generator (PMSG) driven by a variable speed wind turbine and feeding high power single-phase local loads has been proposed. A seven-level cascaded H-bridge inverter employing phase-shifted multi-carrier pulse width modulation is implemented using LabVIEW FPGA. The

Paulson Samuel; Nalamati Chandrashekhar; Rajesh Gupta

2010-01-01

350

Energy transfer processes in solar energy conversion. Final report  

SciTech Connect

The following were studied experimentally and/or theoretically: dynamics of energy transport and trapping in two-component systems (using rhodamine 6G and malachite green as traps), electronic excited state transport among molecules randomly distributed in a finite volume, electronic excitation transport in polymer systems, and excitation transport in synthetic Zn-chlorophyllide substituted hemoglobin. (DLC)

Fayer, M.D.

1984-01-01

351

Conversion of concentrated solar thermal energy into chemical energy.  

PubMed

When a concentrated solar beam is irradiated to the ceramics such as Ni-ferrite, the high-energy flux in the range of 1500-2500 kW/m(2) is absorbed by an excess Frenkel defect formation. This non-equilibrium state defect is generated not by heating at a low heating-rate (30 K/min), but by irradiating high flux energy of concentrated solar beam rapidly at a high heating rate (200 K/min). The defect can be spontaneously converted to chemical energy of a cation-excess spinel structure (reduced-oxide form) at the temperature around 1773 K. Thus, the O(2) releasing reaction (?-O(2) releasing reaction) proceeds in two-steps; (1) high flux energy of concentrated solar beam absorption by formation of the non-equilibrium Frenkel defect and (2) the O(2) gas formation from the O(2-) in the Frenkel defect even in air atmosphere. The 2nd step proceeds without the solar radiation. We may say that the 1st step is light reaction, and 2nd step, dark reaction, just like in photosynthesis process. PMID:22434435

Tamaura, Yutaka

2012-01-01

352

Composite laminate applications in magnetic fusion energy superconducting magnet systems  

Microsoft Academic Search

The application of advanced composite laminates in the cryogenic portion of magnetic fusion energy systems is considered. It is suggested that laminates, characterized by high modulus, low thermal conductivity, and high electrical conductivity, can substitute for stainless steel in some components of superconducting magnets. Thermal insulation, nonmetallic dewars, and superconducting composites are discussed. Problems associated with the use of current

M. B. Kasen

1978-01-01

353

Refractory materials for high-temperature thermoelectric energy conversion  

NASA Astrophysics Data System (ADS)

Theoretical work of two decades ago adequately explained the transport behavior and effectively guided the development of thermoelectric materials of high conversion efficiencies of conventional semiconductors (e.g., SiGe alloys). The more significant contributions involved the estimaiation of optimum doping concentrations, the reduction of thermal conductivity by solid solution doping and the development of a variety of materials with ZT approx. 1 in the temperature range 300 K to 1200 K. ZT approx. 1 is not a theoretical limitation although, experimentally, values in excess of one were not achieved. Work has continued with emphasis on higher temperature energy conversion. A number of promising materials have been discovered in which it appears that ZT 1 is realizable. These materials are divided into two classes: (1) the rare-earth chalcogenides which behave as itinerant highly-degenerate n-type semiconductors at room-temperature, and (2) the boron-rich borides, which exhibit p-type small-polaronic hopping conductivity.

Wood, C.; Emin, D.

1984-09-01

354

Energy Conversion Options for Advanced Radioisotope Power Systems  

NASA Astrophysics Data System (ADS)

Static and dynamic energy conversion technologies for Advanced Radioisotope Power Systems (ARPSs) are reviewed and their impact on the system's total mass and specific electrical power and the amount of 238PuO2 fuel needed for the heat source are assessed and compared. Conversion technologies considered are Segmented and cascaded Thermoelectric, Alkali-Metal Thermal-to-Electric Conversion, and Free Piston Stirling Engines (FPSEs) and, for comparison, SiGe thermoelectric. Estimates for a 100 We ARPS indicate that when using SiGe thermoelectric, operating between 1273 K and 573 K, 8 General Purpose Heat Source (GPHS) modules would be required and the system's specific power is ~ 4.6 We/kg. Using STE converters, operating between 973 K and 373 K, 5 GPHS modules are required and the ARPS's specific power is ~ 7.28 We/kg. The next generation STE converters that could operate between 1273 K and 573 K, for a projected system efficiency of 13.8%, decrease the number of GPHS modules needed to 4 and increase the system's specific power to ~ 9.9 We/kg. With cascaded SiGe-STE converters, operating between 1273 K and 373 K, the system's efficiency could be as much as 16%, requiring only 3 GPHS modules, for an estimated specific power of 10.7 We/kg. This specific power is more than twice that for SOA RTG. With the current version 1.0 of FPSEs, the 100 We ARPS needs only two GPHS modules, but its specific power (4.1 we/kg) is slightly lower than that of SOA RTG (4.6 We/kg). Future introduction of versions 1.1 and 2.0 engines, with slightly higher conversion efficiency and significantly lower mass, could increase the system's specific power to ~ 7.5 We/kg, using the same number of GPHS modules as version 1.0 engines. With Na-AMTEC and K-AMTEC, the 100 We ARPS needs 3 and 4 GPHS modules, respectively, for an estimated specific power of 5.3 and 5.8 We/kg, respectively.

El-Genk, Mohamed S.

2003-01-01

355

On the energy conversion and efficiency of a dielectric electroactive polymer generator  

NASA Astrophysics Data System (ADS)

Dielectric electroactive polymers are studied for their energy generating ability based on a variable capacitance mechanism. Energy conversion for one cycle is analyzed by considering the energy loss in the charging process, where generated energy is defined as the difference between output and total input electrical energy. Experiments are conducted under two charging modes and different stretch rates to investigate their effect on the energy conversion. Energy conversion efficiency of up to 18.3% is achieved with charging-while-stretching mode and a low stretch rate, with an energy density of 18.9 mJ/g and power of 3.775 mW/g per cycle obtained.

Wang, Huaming; Wang, Chengshu; Yuan, Tongyan

2012-07-01

356

Direct voltage control for standalone wind energy conversion systems with induction generator and energy storage  

Microsoft Academic Search

A control method for standalone wind energy conversion systems with induction generator and energy storage system (ESS) is proposed in this paper. A fixed-speed self-excited induction generator is directly connected to the standalone power system. An ESS is employed to compensate the power variation from wind generator and load, maintain the power flow balanced. A direct voltage control scheme is

Wei Huang; D. W. Xu

2008-01-01

357

Impact of different macronutrient definitions and energy conversion factors on energy supply estimations  

Microsoft Academic Search

The magnitude of differences in energy supply using different definitions for carbohydrates and protein as well as different energy conversion factors was investigated. Food supply data for 1999–2001 from FAOSTAT were used for nine countries with different types of diets. Nutrient values were derived from USDA and the British food composition tables for three definitions of carbohydrate (total, available by

U. R. Charrondiere; S. Chevassus-Agnes; S. Marroni; B. Burlingame

2004-01-01

358

Site selection for small wind energy conversion systems for US Department of Energy field evaluation program  

Microsoft Academic Search

The site selection procedure followed to locate two qualified sites for the installed and monitoring of two commercially available small wind energy conversion systems as part of the U.S. Department of Energy's Field Evaluation Program is described. The aim of the evaluation program is to gain operating experience with wind systems in actual locations and to identify the siting and

B. H. Bailey

1980-01-01

359

Review of pyroelectric thermal energy harvesting and new MEMs based resonant energy conversion techniques  

SciTech Connect

Harvesting electrical energy from thermal energy sources using pyroelectric conversion techniques has been under investigation for over 50 years, but it has not received the attention that thermoelectric energy harvesting techniques have during this time period. This lack of interest stems from early studies which found that the energy conversion efficiencies achievable using pyroelectric materials were several times less than those potentially achievable with thermoelectrics. More recent modeling and experimental studies have shown that pyroelectric techniques can be cost competitive with thermoelectrics and, using new temperature cycling techniques, has the potential to be several times as efficient as thermoelectrics under comparable operating conditions. This paper will review the recent history in this field and describe the techniques that are being developed to increase the opportunities for pyroelectric energy harvesting. The development of a new thermal energy harvester concept, based on temperature cycled pyroelectric thermal-to-electrical energy conversion, are also outlined. The approach uses a resonantly driven, pyroelectric capacitive bimorph cantilever structure that can be used to rapidly cycle the temperature in the energy harvester. The device has been modeled using a finite element multi-physics based method, where the effect of the structure material properties and system parameters on the frequency and magnitude of temperature cycling, and the efficiency of energy recycling using the proposed structure, have been modeled. Results show that thermal contact conductance and heat source temperature differences play key roles in dominating the cantilever resonant frequency and efficiency of the energy conversion technique. This paper outlines the modeling, fabrication and testing of cantilever and pyroelectric structures and single element devices that demonstrate the potential of this technology for the development of high efficiency thermal-to-electrical energy conversion devices.

Hunter, Scott Robert [ORNL; Lavrik, Nickolay V [ORNL; Mostafa, Salwa [ORNL; Rajic, Slobodan [ORNL; Datskos, Panos G [ORNL

2012-01-01

360

Energy transfer processes in solar energy conversion. Progress report  

SciTech Connect

We have made substantial progress in experimental and theoretical studies in two areas: Photoinduced donor to acceptor electron transfer followed by back transfer in random solutions; and electronic excitation transport in systems with complex inhomogeneous spatial geometries and inhomogeneous energy distributions. Through the development of accurate statistical mechanical theories, we have been able to relate dynamics in complex systems to experimental observables. We have then used the experimental observables, time resolved fluorescence depolarization and transient grating experiments, to examine well defined molecular systems. The agreement between theory and experiment is excellent. 11 refs.

Fayer, M.D.

1989-11-01

361

High-temperature thermoelectric energy conversion. II - Materials survey  

NASA Astrophysics Data System (ADS)

The current status of materials research for high-temperature thermoelectric energy conversion is reviewed. Two general classes of materials show promise for high temperature figure of merit (Z) values, viz, the rare-earth chalcogenides and the boron-rich borides. The electronic transport properties of the rare-earth chalcogenides are explicable on the basis of degenerate or partially degenerate n-type semiconductors. Boron and boron-rich borides exhibit p-type hopping conductivity, with detailed explanations proposed for the transport differing from compound to compound. Some discussion is presented on the reasons for the low thermal conductivities in these materials. Also, ZTs greater than one appear to have been realized at high temperature in many of these compounds.

Wood, C.

362

Frataxin activates mitochondrial energy conversion and oxidative phosphorylation  

PubMed Central

Friedreich's ataxia (FA) is an autosomal recessive disease caused by decreased expression of the mitochondrial protein frataxin. The biological function of frataxin is unclear. The homologue of frataxin in yeast, YFH1, is required for cellular respiration and was suggested to regulate mitochondrial iron homeostasis. Patients suffering from FA exhibit decreased ATP production in skeletal muscle. We now demonstrate that overexpression of frataxin in mammalian cells causes a Ca2+-induced up-regulation of tricarboxylic acid cycle flux and respiration, which, in turn, leads to an increased mitochondrial membrane potential (??m) and results in an elevated cellular ATP content. Thus, frataxin appears to be a key activator of mitochondrial energy conversion and oxidative phosphorylation.

Ristow, Michael; Pfister, Markus F.; Yee, Andrew J.; Schubert, Markus; Michael, Laura; Zhang, Chen-Yu; Ueki, Kojhiro; Michael, M. Dodson; Lowell, Bradford B.; Kahn, C. Ronald

2000-01-01

363

Siting handbook for small wind energy conversion systems  

SciTech Connect

This handbook was written to serve as a siting guide for individuals wishing to install small wind energy conversion systems (WECS); that is, machines having a rated capacity of less than 100 kilowatts. It incorporates half a century of siting experience gained by WECS owners and manufacturers, as well as recently developed siting techniques. The user needs no technical background in meteorology or engineering to understand and apply the siting principles discussed; he needs only a knowledge of basic arithmetic and the ability to understand simple graphs and tables. By properly using the siting techniques, an owner can select a site that will yield the most power at the least installation cost, the least maintenance cost, and the least risk of damage or accidental injury.

Wegley, H.L.; Ramsdell, J.V.; Orgill, M.M.; Drake, R.L.

1980-03-01

364

Biomass energy conversion and utilization in the developing countries  

SciTech Connect

Information on the conversion and use of biomass energy is summarized and pictorially illustrated in this manual. Section I presents the basic principles of anaerobic digestion and shows how to design and construct biogas plants. Topics covered include: the digestion process; carbon-nitrogen ratio; temperature dependency; Indian- and Chinese-type and horizontal digesters; alternative designs; manure production; gas production and use; cooking; lighting; refrigeration; shaft power; power generation; waste heat recovery; sludge use. Health, economic/financial, policy, and socio-economic aspects are also noted, and the construction details, design, and cost of a 4-cubic-meter Chinese-type digester are included. Subsequent sections treat biomass gasification (covering gasifier types, systems, fuels, sizing; uses in stationary engines, process heat, electrical power, and vehicle propulsion; economic and deforestation issues) and the production of fuel alcohol (raw materials, production technology, stillage digestion, ethanol fuel, costs).

Bush, M.

1985-05-01

365

Chemical conversion surfaces for solar-energy applications  

SciTech Connect

One of the major impediments to the utilization of solar energy is the initial cost of the systems. One mechanism for reducing this initial cost is reduction of component costs. Present-day selective coatings are relatively expensive, costing $10 to $20/m/sup 2/ ($1 to $2 per ft/sup 2/). Chemical conversion coating of substrate materials is a means by which selective coatings might be produced for low-temperature active and passive applications at a low cost. Some researchers have predicted chemical costs of only a few cents per ft/sup 2/. Much information is needed for both optical property optimization and durability to see if any of these coatings might hold promise for solar applications. This study is an attempt to determine which coatings and substrate combinations might hold the greatest promise. The following substrate materials are investigated: aluminum, copper, brass, zinc, cadmium, aluminum/zinc alloys, nickel, iron, and stainless steel.

Moore, S.W.; Clements, J.S.; Doty, W.R.

1983-08-01

366

Photochemical energy conversion by membrane-bound photoredox systems  

NASA Astrophysics Data System (ADS)

Most of our effort during the past grant period has been directed towards investigating electron transfer processes involving redox proteins at lipid bilayer/aqueous interfaces. This theme, as was noted in our previous three year renewal proposal, is consistent with our goal of developing biomimetic solar energy conversion systems which utilize the unique properties of biological electron transfer molecules. Thus, small redox proteins such as cytochrome c, plastocyanin and ferredoxin function in biological photosynthesis as mediators of electron flow between the photochemical systems localized in the membrane, and more complex soluble or membrane bound redox proteins which are designed to carry out specific biological tasks such as transbilayer proton gradient formation, dinitrogen fixation, ATP synthesis, dihydrogen synthesis, generation of strong reductants, etc. In these studies, we have utilized two principal experimental techniques, laser flash photolysis and cyclic voltammetry, both of which permit direct measurements of electron transfer processes.

Tollin, G.

1992-03-01

367

Standards for photovoltaic energy conversion systems. Final report  

SciTech Connect

This report provides the results of a search for existing domestic standards and related documents for possible application in the development of a standards base for photovoltaic energy conversion systems. The search resulted in locating about 150 test methods, recommended practices, standards, solar-thermal performance criteria, and other standards-related documents. They are listed by topic areas in the appendix. The listing was prepared to assist those involved in developing performance criteria for photovoltaic systems and in identifying methods to test system performance against these criteria. It is clear from the results of the search that few standards are directly applicable to terrestrial solar photovoltaic systems and that much standards development is required to support the commercialization of such systems.

Schafft, H. A.

1980-04-01

368

A Review of Previous Research in Direct Energy Conversion Fission Reactors  

Microsoft Academic Search

From the earliest days of power reactor development, direct energy conversion was an obvious choice to produce high efficiency electric power generation. Directly capturing the energy of the fission fragments produced during nuclear fission avoids the intermediate conversion to thermal energy and the efficiency limitations of classical thermodynamics. Efficiencies of more than 80% are possible, independent of operational temperature. Direct

HENRY DUONG; GARY F. POLANSKY; THOMAS L. SANDERS; MALCOLM D. SIEGEL

1999-01-01

369

Functional materials with high-efficiency energy storage and conversion for batteries and fuel cells  

Microsoft Academic Search

Electrochemical energy storage and conversion with high efficiency and cleanliness is unquestionably one challenge for the sustainable development of the society of human beings. The functional materials can be applied in the systems of electrochemical energy storage and conversion such as in the fields of batteries and fuel cells. For the aspect of energy storage, high efficiency is closely connected

Bo Peng; Jun Chen

2009-01-01

370

Demonstration and Analysis of Combined Wind-Solar Energy Conversion Systems. Final Report.  

National Technical Information Service (NTIS)

This study has examined the practicality of combined wind-solar energy conversion system (CW-SECS), connected to a common storage facility to produce thermal energy. Coupling a combined wind-solar energy conversion system with an appropriately designed st...

L. Icerman A. Swift K. Myers W. Cargal

1981-01-01

371

A PRELIMINARY STUDY OF THE POTENTIAL TO KINETIC ENERGY CONVERSION PROCESS IN THE STRATOSPHERE  

Microsoft Academic Search

The potential to kinetic energy conversion process in the lower ; stratosphere is evaluated using adiabatically derived vertical velocities for the ; North American region for a five-day period. Preliminary results suggest the ; possibility that on the average the kinetic energy of stratospheric motions may ; not result from a conversion of potential energy within the stratosphere. The ;

R. M. White; G. F. Nolan

1959-01-01

372

Modeling and controller design of a wind energy conversion system with matrix converter  

Microsoft Academic Search

In order to meet increasing power demand, taking into account economical and environmental factors, wind energy conversion is gradually gaining interest as a suitable source of renewable energy. In this paper, The modeling of the Wind Energy Conversion System(WECS) with Matrix converter is proposed. The Space Vector Modulation (SPVM) technique is used for matrix converter to control the generator rotor

Y. S. Rao; A. J. laxmi; K. M. S. N. Krishna

2011-01-01

373

Magnetic Fusion Energy Research and Development.  

National Technical Information Service (NTIS)

This report on the Department of Energy's Magnetic Fusion Program was requested by the Secretary of Energy. The Panel finds that substantial progress has been made in the three years since the previous ERAB review, although budget constraints have preclud...

1984-01-01

374

Flywheel energy storage with superconductor magnetic bearings  

SciTech Connect

A system for storing energy in a flywheel suspended by magnetic levitation in a vacuum vessel is described comprising: a rotatable member having a rotation axis in a central shaft said shaft having first and second magnetic tips formed from permanent magnets on opposite ends thereof, superconductor magnetic bearings, positioned to support said first and second magnetic tips and supported in turn by bearing support means, said superconductor magnetic bearings having a main direction of lift; cooling means in thermal contact with said bearing support means; and energy transfer means, connected to said rotatable member, for transferring energy into and extracting energy from said rotatable member, characterized in that: at least one of said superconducting bearings includes a lifting portion comprising melt-processed, directionally solidified material structure having a crystal structure C-axis oriented parallel to said main direction of lift.

Weinberger, B.R.; Lynds, L. Jr.

1993-06-01

375

Permanent Magnet Synchronous Generator-Based Standalone Wind Energy Supply System  

Microsoft Academic Search

In this paper, a novel algorithm, based on dc link voltage, is proposed for effective energy management of a stand- alone permanent magnet synchronous generator (PMSG)-based variable speed wind energy conversion system consisting of bat- tery, fuel cell, and dump load (i.e., electrolyzer). Moreover, by maintaining the dc link voltage at its reference value, the output ac voltage of the

C. N. Bhende; S. Mishra; Siva Ganesh Malla

2011-01-01

376

Power conversion and control methods for renewable energy sources  

NASA Astrophysics Data System (ADS)

In recent years, there has been an increase in the use of renewable energy due to the growing concern over the pollution caused by fossil-fuel-based energy. Renewable energy sources, such as photovoltaic (PV) and fuel cell, can be used to enhance the safety, reliability, sustainability, and transmission efficiency of a power system. This dissertation focuses on the power conversion and control for two major renewable-energy sources: PV and fuel cell. Firstly, a current-based, maximum power-point tracking (MPPT) algorithm is proposed for PV energy. An economical converter system using the above scheme for converting the output from PV panels into 60 Hz AC voltage is developed and built. Secondly, a novel circuit model for the Proton Exchange Membrane (PEM) fuel-cell stack that is useful in the design and analysis of fuel-cell-based power systems is proposed. This Pspice-based model uses elements available in the Pspice library with some modifications to represent both the static and dynamic responses of a PEM fuel-cell module. The accuracy of the model is verified by comparing the simulation and experimental results. Thirdly, a DSP-controlled three-phase induction-motor drive using constant voltage over frequency is built and can be used in a fuel-cell automobile. A hydrogen sensor is used in the drive to both sound an alarm and shut down the inverter trigger pulses through the DSP. Finally, a hybrid power system consisting of PV panels and fuel cell is proposed and built. In the proposed system, PV panels can supply most of the power when the sunlight is available, and the excess power required by the load is supplied by a fuel cell. Load sharing between a fuel cell (FC) and the PV panel is investigated by both simulation and experiments.

Yu, Dachuan

377

Magnetic power conversion with machines containing full or porous wheel heat exchangers  

NASA Astrophysics Data System (ADS)

A first part of the article contains a thermodynamic theory describing the temperature distribution in a Curie wheel. The occurring nonlinear ordinary differential equation has an analytical solution. If a Curie wheel is stabilized by levitation, it is named Palmy wheel. These wheels show a full structure, and because of this reason, their uptake of heat from a flame (Curie wheel) or by (solar) light absorption (Palmy wheel) only on the periphery of a cylinder is very limited. To improve the method, a modification of the principle by introducing a convective heat transport into a porous wheel is discussed. By this the power conversion rate from a heat flux to mechanical and electric power is very much increased. The second part of the article presents results of a theoretical/numerical study on the efficiencies of magnetic power conversion plants operating with porous wheels. Furthermore, these efficiencies—which are promising—are compared with those of existing power conversion plants, as e.g. geothermal binary cycle power plants.

Egolf, Peter W.; Kitanovski, Andrej; Diebold, Marc; Gonin, Cyrill; Vuarnoz, Didier

2009-04-01

378

Oxidant system improvements for MHD energy conversion and industrial processes  

NASA Astrophysics Data System (ADS)

An in-depth study was conducted to identify possible improvements to the oxidant supply system for combined cycle MHD power plants which would lead to higher thermal efficiency and reduction in the cost of electricity, COE. Results showed that the oxidant system energy consumption could be minimized when the process was designed to deliver a product O2 concentration of 70 mole percent. The study also led to the development of a new air separation process, referred to as 'liquid pumping and internal compression'. MHD system performance calculations show that the new process would permit an increase in plant thermal efficiency of 0.6 percent while allowing more favorable tradeoffs between magnetic energy and oxidant system capacity requirements.

Juhasz, A. J.

1983-12-01

379

Direct energy conversion in fission reactors: A U.S. NERI project  

SciTech Connect

In principle, the energy released by a fission can be converted directly into electricity by using the charged fission fragments. The first theoretical treatment of direct energy conversion (DEC) appeared in the literature in 1957. Experiments were conducted over the next ten years, which identified a number of problem areas. Research declined by the late 1960's due to technical challenges that limited performance. Under the Nuclear Energy Research Initiative the authors are determining if these technical challenges can be overcome with todays technology. The authors present the basic principles of DEC reactors, review previous research, discuss problem areas in detail, and identify technological developments of the last 30 years that can overcome these obstacles. As an example, the fission electric cell must be insulated to avoid electrons crossing the cell. This insulation could be provided by a magnetic field as attempted in the early experiments. However, from work on magnetically insulated ion diodes they know how to significantly improve the field geometry. Finally, a prognosis for future development of DEC reactors will be presented .

SLUTZ,STEPHEN A.; SEIDEL,DAVID B.; POLANSKY,GARY F.; ROCHAU,GARY E.; LIPINSKI,RONALD J.; BESENBRUCH,G.; BROWN,L.C.; PARISH,T.A.; ANGHAIE,S.; BELLER,D.E.

2000-05-30

380

Eddy shedding and energy conversions in the East Australian Current  

NASA Astrophysics Data System (ADS)

Mesoscale variability and eddy shedding in the Tasman Sea, particularly of the East Australian Current (EAC), is studied through the analysis of remotely sensed observations and outputs from a global ocean model. Previous observations of the western boundary current separation from the coast showed strong variability at periods ranging between 90 and 140 days. We show from satellite altimetric observations that rapid northward migration of the separation point of the EAC follows the formation of large eddies at periods of ˜100 days. After an eddy separation event the normally southward flowing current swiftly assumes a more zonal configuration near the separation latitude, with a cyclonic circulation developing inshore. The formation of large separation eddies is preceded by the southward propagation of sea level anomalies along the east Australian continental slope. From 25°S, sea level anomalies grow as they travel south, eventually being pinched off in the form of large anticyclones at ˜32°S, in the current retroflection area. Energy conversion terms in a global ocean model and in altimetric data suggest both barotropic and baroclinic instability may account for the growth of these anomalies as they propagate south. East of the main EAC jet there is evidence that eddies may be feeding potential energy back to the mean flow.

Mata, Mauricio M.; Wijffels, Susan E.; Church, John A.; Tomczak, Matthias

2006-09-01

381

Energy conversion of the flare due to direct electric fields from the sheared reconnection  

NASA Astrophysics Data System (ADS)

In this paper we present a new mechanism of the main energy conversion of the solar flare. Since a flare inducing prominence (flux tube) rises Vz ? 300 km s-1, the plasmas below it cannot continuously eject with Alfvén speeds of VA = 3000 km s-1 but probably with Vz ? ±100 km s-1. Plasma up and downflows with VA will within a short duration be blocked between the chromosphere where reconnected flux tubes are piling up, and the slowly rising flux rope. Hence the Petschek slow shock mechanism is difficult to be realized as a major energy converting mechanism. Adopting a conventional reconnecting morphology, we assume a magnetic component parallel to the photospheric neutral line, i.e. sheared fields of By ? 0. Then Gauss’s law leads to non-vanishing electric charges ?; 4?? = -div(V × B/c) ? By?Vz/c?x where the horizontal inflow velocity Vx changes to vertical down-flow Vz (e.g. By ? Bz = 40G and ?x ? 104 km). Then the electric field parallel to the magnetic fields E? calculated from Coulomb’s law from this ? is found to be far greater than the Dreicer field, and accelerates electrons and protons. Thus the horizontally inflowing Poynting energy flux in area Sx is immediately converted to the kinetic energy of electron beams along the magnetic field in area Sz; BVxSx/4?=12menVbeam3Sz with Sx/Sz ? 4. The particle beam energy flux cannot exceed the Poynting energy flux however large E? may be. The total energy can be supplied by 10 keV electrons and nbeam = 2 × 107 cm-3 for Vx = 40 km s-1. This inflow velocity Vx, though restricted by the rising prominence speed, explains the short flare duration consistent to observations. The electron beam flux nbeamVbeam will be simultaneously and co-spatially compensated by the slowly back-flowing bulk electrons, avoiding possible enormous charge pile-up. Instead of the conventional diffusion region, which contains serious difficulties if there is the shear as one should normally expect, we propose a reconnecting small region in the potential magnetic fields. The latter may be created by unwinding motions to erase the shear and to minimize energy, and the time scale is given only from the outside condition free from any diffusive processes such as the anomalous resistivity, because no electric currents may exist.

Hirayama, T.

382

Proceedings of the 30. intersociety energy conversion engineering conference. Volume 3  

SciTech Connect

This conference provides a forum to present and discuss the engineering aspects of energy conversion, advanced and unconventional energy systems and devices, energy conversion and utilization, environmental issues and policy implications on research, development, and implementation of technologies. The solution for a sustainable future will lie in a mix of all of the available energy resources (renewable and non-renewable) and diverse energy conversion technologies that will maintain quality of life in a sustainable manner. The 78 papers in this volume are divided into the following topical sections: (1) Conversion technologies--Heat pumps; Advanced cycles; Thermoelectrics; Thermionics; and AMTEC; (2) Electrochemical conversion--Fuel cells and Batteries for terrestrial applications; (3) New technologies for energy utilization (including Superconductivity); and (4) Stirling cycles and machines--Stirling engine development; Stirling component analysis/testing; Stirling machine simulation and optimization; and Stirling machine analysis. All papers have been processed separately for inclusion on the data base.

Goswami, D.Y. [ed.] [Univ. of Florida, Gainesville, FL (United States); Kannberg, L.D.; Somasundaram, S. [eds.] [Pacific Northwest Lab., Richland, WA (United States); Mancini, T.R. [ed.] [Sandia National Labs., Albuquerque, NM (United States)

1995-12-01

383

Resonant high energy graviton to photon conversion at the post-recombination epoch  

NASA Astrophysics Data System (ADS)

Resonant conversion of high energy gravitons into photons in large scale cosmological magnetic fields at the post-recombination epoch is considered. It is shown that the probability of the resonance photon production is much higher than the nonresonant one. As a result, an observable isotropic background of cosmic gamma rays might be created. As shown in our previous paper, an early population of primordial black holes prior to big bang nucleosynthesis could be an efficient source of high frequency gravitational waves. For the primordial black hole mass, about 108g, the produced photons would be the dominant component of the soft to hard cosmic x-ray background and for lower masses the spectrum is shifted down to the ultraviolet and optic.

Dolgov, Alexander D.; Ejlli, Damian

2013-05-01

384

Investigation and development of new materials for electrochemical energy conversion  

NASA Astrophysics Data System (ADS)

Performance of next generation electrochemical energy conversion devices relies on optimization of both ion selective membranes that retain conductivity at elevated temperatures, and electrode materials active and stable in corrosive environment. The work presented focuses on (1) improving energy conversion in fuel cells by designing novel ion conductive membrane materials optimized by an original optical high-throughput screening technique and (2) development of new stable mixed transition metal sulfide electrocatalysts for industrial bromine recovery. A functionalized fullerene derivative was used to fabricate mechanically strong, flexible organic-inorganic membranes via cooperative sol-gel synthesis. Amorphous materials with nanometer range wormlike structures were obtained. The dependence of conductivity on the concentration of triflic acid was quantitatively described by percolation theory. Fullerene derivatives with arbitrarily attached chains increased disorder of the structure, but before the wormlike network collapsed conductivity 40 times higher than that of the sample with no fullerenes was recorded. This enhancement was attributed to the additional inter-channel connections for proton transport facilitated by the fullerene derivatives. Optimization of the structure by an optical high-throughput screening made possible proton conductivity of 3.2x10-3 S/cm at 130°C and 5% humidity conditions. A series of doped Ru, Fe, Mo, W sulfide catalysts was synthesized, and their hydrogen evolution and oxygen reduction activity in HBr were studied as a function of dopant. RuS2 compounds showed the highest rates of hydrogen evolution and oxygen reduction reactions in HBr. Among all dopants, Co was the most active for hydrogen evolution reaction with overpotentials 100 mV lower than that of Pt at current density of 80 mA/cm2 in 0.5 M HBr. Oxygen reduction activity of RuS2 catalysts was found to change consistently as a function of periodic position of a dopant. Cr, Mn and Fe dopants inhibited oxygen reduction activity of RuS2, while Co, Ni and Cu promoted the activity. Inexpensive Ni-W sulfide was identified as active catalyst for oxygen reduction reaction in HBr. The activity increased with the addition of Ni up to 50%. Although Co-doped RuS2 is unstable in 6 M HBr, it was found to be stable under applied potential during 5 hour hydrogen evolution reaction test.

Ivanovskaya, Anna

385

ECUT (Energy Conversion and Utilization Technologies) program: Biocatalysis project  

NASA Astrophysics Data System (ADS)

The Annual Report presents the fiscal year (FY) 1988 research activities and accomplishments, for the Biocatalysis Project of the U.S. Department of Energy, Energy Conversion and Utilization Technologies (ECUT) Division. The ECUT Biocatalysis Project is managed by the Jet Propulsion Laboratory, California Institute of Technology. The Biocatalysis Project is a mission-oriented, applied research and exploratory development activity directed toward resolution of the major generic technical barriers that impede the development of biologically catalyzed commercial chemical production. The approach toward achieving project objectives involves an integrated participation of universities, industrial companies and government research laboratories. The Project's technical activities were organized into three work elements: (1) The Molecular Modeling and Applied Genetics work element includes research on modeling of biological systems, developing rigorous methods for the prediction of three-dimensional (tertiary) protein structure from the amino acid sequence (primary structure) for designing new biocatalysis, defining kinetic models of biocatalyst reactivity, and developing genetically engineered solutions to the generic technical barriers that preclude widespread application of biocatalysis. (2) The Bioprocess Engineering work element supports efforts in novel bioreactor concepts that are likely to lead to substantially higher levels of reactor productivity, product yields and lower separation energetics. Results of work within this work element will be used to establish the technical feasibility of critical bioprocess monitoring and control subsystems. (3) The Bioprocess Design and Assessment work element attempts to develop procedures (via user-friendly computer software) for assessing the energy-economics of biocatalyzed chemical production processes, and initiation of technology transfer for advanced bioprocesses.

Baresi, Larry

1989-03-01

386

An Application of Flywheel Energy Storage System for Wind Energy Conversion  

Microsoft Academic Search

Recently, the use of wind energy conversion system (WECS) is increasing all over the world. Wind generators with several mega-watt rating have been developed and installed in wind farms, therefore, the influence of WECS on power system is becoming greater. Particularly a frequency variation of power system is a significant problem. This will damage to power quality, and cause a

R. Takahashi; Li Wu; T. Murata; J. Tamura

2005-01-01

387

Selection of an asynchronized synchronous generator for a wind energy conversion system  

Microsoft Academic Search

A wind energy conversion system with an asynchronized synchronous generator operating in parallel with a high-power network is described. Based on analysis of the range of efficient operating regimes of the wind energy conversion system, an optimum control algorithm is developed for the asynchronized synchronous generator which provides maximum power generation for a given range of rotation frequencies. Recommendations concerning

L. Ia. Shapiro; V. I. Astorga

1986-01-01

388

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

Microsoft Academic Search

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

Z. Chen; Y. Hu

2004-01-01

389

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

Microsoft Academic Search

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

C. Hopkins

2009-01-01

390

Analysis of Energy Conversion Systems, Including Material and Global Warming Aspects  

Microsoft Academic Search

This paper addresses a method for the overall evaluation of energy conversion systems, including material and global environmental aspects. To limit the scope of the work reported here, the global environmental aspects have been limited to global warming aspects.A method is presented that uses exergy as an overall evaluation measure of energy conversion systems for their lifetime. The method takes

Mingyuan Zhang; Gordon M. Reistad

1998-01-01

391

Synchronization techniques comparison for sensorless control applied to Wind Energy Conversion Systems (WECS)  

Microsoft Academic Search

This paper encompasses a comparative study of techniques for position and speed estimation applied to wind energy conversion systems (WECS), connected to a distribution grid by means of a back to back converter. In the context of low and medium power wind energy conversion systems, the robustness of several sensorless techniques are studied taking into account the tolerance of the

L. G. Gonzalez; E. Figueres; G. Garcera; O. Carranza; Fran González-Espín

2009-01-01

392

Fuzzy Based Output Feedback Control for wind energy conversion System: An LMI Approach  

Microsoft Academic Search

This paper addresses the problem of regulating wind energy conversion system by using fuzzy output feedback controller. First, a Takagi-Sugeno fuzzy model is employed to represent the nonlinear dynamics of the wind energy conversion system. Then, based on the fuzzy model and utilizing the concept of parallel distributed compensation, a fuzzy observer based fuzzy controller is developed to stabilize the

A. H. Besheer; H. M. Emara

2006-01-01

393

Observation of early photon conversions in high-energy cosmic-ray interactions  

SciTech Connect

High energy cosmic ray interactions were studied by the JACEE Collaboration using balloon-borne emulsion chambers at high altitude. In high energy, yet low multiplicity interactions many secondary vertices were observed, probably due to decays of short-lived particles. Early conversions of photons were found in the vicinity of these vertices. Conversion distances and angular distributions of the photons were studied.

Asakimori, K. (Kobe Women's Junior College, Kobe (Japan)); Burnett, T.H. (University of Washington, Seattle, WA (United States)); Cherry, M.L. (Louisiana State University (United States)); Christl, M.J. (G. Marshall Space Flight Center/NASA (United States)); Dake, S. (Kobe Unibersity, Kobe (Japan)); Derrickson, J.H.; Fountain, W.F. (G. Marshall Space Flight Center/NASA (United States)); Fuki, M. (Kochi University (Japan)); Gregory, J.C.; Hayashi, T. (University of Alabama, Huntsville, AL (United States)); Holynski, R. (Institute for Nuclear Physics, Krakow (Poland)); Iwai, J. (University of Washington, Seattle, WA (United States)); Iyono, A. (Okayama University of Science (Japan)); Jones, W.V. (Louisiana State University (United States)); Jurak, A. (Institute for Nuclear Physics, Krakow (Poland)); Lord, J.J. (University of Washington,Seattle WA (United States)); Miyamura, O. (Hiroshima University, Hiroshima (Japan)); Oda, H. (Kobe University, Kobe (Japan)); Ogata, T. (I; The JACEE Collaboration

1993-06-15

394

Observation of early photon conversions in high-energy cosmic-ray interactions  

NASA Astrophysics Data System (ADS)

High energy cosmic ray interactions were studied by the JACEE Collaboration using balloon-borne emulsion chambers at high altitude. In high energy, yet low multiplicity interactions many secondary vertices were observed, probably due to decays of short-lived particles. Early conversions of photons were found in the vicinity of these vertices. Conversion distances and angular distributions of the photons were studied.

Asakimori, K.; Burnett, T. H.; Cherry, M. L.; Christl, M. J.; Dake, S.; Derrickson, J. H.; Fountain, W. F.; Fuki, M.; Gregory, J. C.; Hayashi, T.; Ho?Y?ski, R.; Iwai, J.; Iyono, A.; Jones, W. V.; Jurak, A.; Lord, J. J.; Miyamura, O.; Oda, H.; Ogata, T.; Olson, E. D.; Parnell, T. A.; Roberts, F. E.; Strausz, S. C.; Takahashi, Y.; Tominaga, T.; Watts, J. W.; Wefel, J. P.; Wilczy?ska, B.; Wilczy?ski, H.; Wilkes, R. J.; Wolter, W.; Wosiek, B.; Zager, E. L.

1993-06-01

395

MPPT of VSCF wind energy conversion system using extremum control strategy  

Microsoft Academic Search

This paper presents the energy conversion optimization control strategy for a horizontal axis variable speed fixed pitch wind energy conversion system, which works in the partial load region. The system uses a variable speed wind turbine (VSWT), driving a squirrel-cage induction generator (SCIG) connected to a grid. Reference to the wind turbine model and its parameters are poorly known, so

Dafeng Fu; Yan Xing; Yundong Ma

2010-01-01

396

Assessment of risk-based capacity benefit factors associated with wind energy conversion systems  

Microsoft Academic Search

A wind energy conversion system (WECS) has a different impact on the load carrying capability of a generating system than does a conventional energy conversion system. This is mainly due to the variation in wind velocity. Two risk-based capacity indices designated as load carrying capacity benefit ratio (LCCBR) and equivalent capacity rate (ECR) are introduced in this paper. These two

R. Billinton; Hua Chen

1998-01-01

397

Conversion Contraption  

NSDL National Science Digital Library

It's show time for eighth grade physical science students after a week of designing, building, and refining Conversion Contraptions. The contraptions are fun combinations of moving parts that use many forms of energy and many conversions of energy. It's t

Chahrour, Janet

2000-09-01

398

Roles for solar thermal conversion systems in our energy economy  

Microsoft Academic Search

The NSF solar thermal conversion program, which is at a conceptual analysis and exploratory research level, is outlined with respect to mission, system, subsystem, and components and materials. Major conclusions are that solar thermal conversion electrical powerplants are most competitive with fossil fuels powerplants for intermediate or peaking power applications, and that central receiver solar thermal systems appear to offer

D. F. Spencer; A. B. Greenberg

1975-01-01

399

Optimized Helium-Brayton Power Conversion for Fusion Energy Systems  

Microsoft Academic Search

This paper presents an overview and a few point designs for multiple-reheat helium Brayton cycle power conversion systems using molten salts (or liquid metals or direct helium cooling). All designs are derived from the General Atomics GT-MHR power conversion unit (PCU). The important role of compact, offset fin heat exchangers for heat transfer to the power cycle helium, and the

Zhao Haihua; Grant Fukuda; Ryan P. Abbott; Per F. Peterson

2005-01-01

400

Ocean Thermal Energy Conversion (OTEC) Programmatic Environmental Analysis--Appendices  

SciTech Connect

The programmatic environmental analysis is an initial assessment of Ocean Thermal Energy Conversion (OTEC) technology considering development, demonstration and commercialization. It is concluded that the OTEC development program should continue because the development, demonstration, and commercialization on a single-plant deployment basis should not present significant environmental impacts. However, several areas within the OTEC program require further investigation in order to assess the potential for environmental impacts from OTEC operation, particularly in large-scale deployments and in defining alternatives to closed-cycle biofouling control: (1) Larger-scale deployments of OTEC clusters or parks require further investigations in order to assess optimal platform siting distances necessary to minimize adverse environmental impacts. (2) The deployment and operation of the preoperational platform (OTEC-1) and future demonstration platforms must be carefully monitored to refine environmental assessment predictions, and to provide design modifications which may mitigate or reduce environmental impacts for larger-scale operations. These platforms will provide a valuable opportunity to fully evaluate the intake and discharge configurations, biofouling control methods, and both short-term and long-term environmental effects associated with platform operations. (3) Successful development of OTEC technology to use the maximal resource capabilities and to minimize environmental effects will require a concerted environmental management program, encompassing many different disciplines and environmental specialties. This volume contains these appendices: Appendix A -- Deployment Scenario; Appendix B -- OTEC Regional Characterization; and Appendix C -- Impact and Related Calculations.

Authors, Various

1980-01-01

401

Fluidized-bed energy technology for biomass conversion  

SciTech Connect

Fluidized-bed technology offers several unique features for use in small-scale biomass energy conversion. Results are reported in the use of a 61-cm fluidized-bed reactor for combustion and on the use of 61-, 30-, and 5-cm reactors for gasification. combustion trials using agricultural biomass feeds have identified several problem areas. Slagging and fouling can occur at bed temperatures as low as 760/sup 0/C. Moreover, metal coupons placed in the hot exhaust gas stream experienced high rates of corrosion and erosion. Gasification experiments have confirmed that a fluidized bed will accept a wide range of biomass feeds (rice hulls, corncobs, sorghum stalks, cottom gin trash) and convert them into a low-Btu combustible gas. Slagging and fouling were not as severe when operating the fluidized bed in the gasification mode. Gas cleanup requirements as well as technical needs in evaluating corrosion of reactor construction materials are identified. Coupling of the 61-cm reactor to a steam boiler is described. Finally, the nature of fluidized-bed technology suggests potentials for biomass pyrolysis, and such use is examined. 2 figures, 5 tables.

Soltes, E.J.; Lepori, W.A.; Pollock, T.C.

1982-01-01

402

Draft environmental assessment: Ocean Thermal Energy Conversion (OTEC) Pilot Plants  

SciTech Connect

This Environmental Assessment (EA) has been prepared, in accordance with the National Environmental Policy Act of 1969, for the deployment and operation of a commercial 40-Megawatt (MW) Ocean Thermal Energy Conversion (OTEC) Pilot Plant (hereafter called the Pilot Plant). A description of the proposed action is presented, and a generic environment typical of the candidate Pilot Plant siting regions is described. An assessment of the potential environmental impacts associated with the proposed action is given, and the risk of credible accidents and mitigating measures to reduce these risks are considered. The Federal and State plans and policies the proposed action will encompass are described. Alternatives to the proposed action are presented. Appendix A presents the navigation and environmental information contained in the US Coast Pilot for each of the candidate sites; Appendix B provides a brief description of the methods and calculations used in the EA. It is concluded that environmental disturbances associated with Pilot Plant activities could potentially cause significant environmental impacts; however, the magnitude of these potential impacts cannot presently be assessed, due to insufficient engineering and environmental information. A site- and design-specific OTEC Pilot Plant Environmental Impact Statement (EIS) is required to resolve the potentially significant environmental effects associated with Pilot Plant deployment and operation. (WHK)

Sullivan, S.M.; Sands, M.D.; Donat, J.R.; Jepsen, P.; Smookler, M.; Villa, J.F.

1981-02-01

403

Advanced materials development for fossil energy conversion applications  

SciTech Connect

Research activities being conducted as part of this project include: (1) fundamental studies of electrochemical processes occurring at surfaces and interfaces in fuel cells, and (2) development of novel materials synthesis and processing methodologies for fossil energy conversion applications. Complex impedance and dc polarization studies of the electrocatalytic activity at the cathode have allowed intrinsic materials properties to be separated from extrinsic properties related to morphology. Mixed conduction in cathode materials was shown to dramatically enhance electrocatalytic activity with this approach. Combustion synthesis methods were used to prepare multicomponent perovskite catalysts in the La{sub 1-x}Sr{sub x}Co{sub 1-y}Fe{sub y}O{sub 3} system. Electronic properties of these catalysts can be altered by adjusting the composition, which affects both catalytic activity and selectivity. Inverse micelles have been utilized to prepare nanosized nickel sulfide particles, which show promise as hydrodesulfurization catalysts for liquefied coal. Self-assembling organic monolayers and derivatized inorganic surfaces have been used to control nucleation and crystal morphology of inorganic phases.

Bates, J.L.; Chick, L.A.; Kingsley, J.J.; Pederson, L.R.; Weber, W.J.; Youngblood, G.E. [Pacific Northwest Lab., Richland, WA (United States); Hurst, J.K.; Bell, A.E.; Grainger, D.W.; Rananavare, S.B.; Roe, D.K.; Thompson, D.H. [Oregon Graduate Inst. of Science and Technology, Beaverton, OR (United States)

1992-05-01

404

Photovoltaic solar energy conversion in the '80s  

NASA Astrophysics Data System (ADS)

The potential for photovoltaic solar energy conversion in the generation of electricity to meet the needs of industrial and developing nations in the 1980s is discussed. The current technology of photovoltaic cells and modules, which are for the most part based on single crystal silicon and can deliver peak powers of 2 to 40 W at 6 to 12 V, is reviewed and prospects for cost reduction in the short- and medium-term by the development of new materials and production methods and increased cell efficiency and in the long term by the development of thin film cells, alternative compounds and mass production are indicated. Possible applications of photovoltaic-derived electricity are pointed out, including educational television receivers, rural telephones, refrigerators, water pumping and hospitals in developing nations and telecommunications, cathodic protection, signaling, telemetry and low-power pumping applications in industrial nations. Predictions of a photovoltaic peak Watt installed costing less than 10 francs by 1990 and a market above 100 MW in 1985 are pointed out.

Chevalier, I.

1981-04-01

405

Shelf mounted Ocean Thermal Energy Conversion platform (revised preliminary report)  

SciTech Connect

This report relates model tests of a generic Ocean Thermal Energy Conversion (OTEC) platform. The objective of these tests is to aid in the evaluation of new OTEC designs and to present a data base for design purposes. The test plan has been designed to provide a data base for design purposes. The test plan has been designed to provide a data base for comparison with current and projected analytical tools as well as comparisons of results from one model configuration to another. The new conceptual OTEC designs are different from the typical offshore (jacket type) structure which is quite transparent to waves. The major difference is the addition of large submerged power production modules to the frame. These proposed modules offer a large surface area to obstruct the flow and thereby increase the global wave forces acting on the structure. Three parameters can be identified to characterize the effect that the obstruction has on the hydrodynamical forces. They are the amount of blockage present, the location of the blockage and the manner in which blockage is realized.

Not Available

1984-03-01

406

Energy-Reliability Optimization of Wind Energy Conversion Systems by Sliding Mode Control  

Microsoft Academic Search

This paper describes a manner in which the energy-reliability optimization of wind energy conversion systemspsila operation can be achieved by means of the sliding mode control. The proposed approach aims at designing a tradeoff between maximizing the power harvested from wind by a horizontal-axis-grid-connected variable-speed doubly-fed-induction-generator-based wind power system and minimizing its mechanical stress. An appropriate sliding surface has been

Iulian Munteanu; Seddik Bacha; Antoneta Iuliana Bratcu; JoËl Guiraud; Daniel Roye

2008-01-01

407

Dependence of beam direct energy conversion on beam energy and current in neutral beam injection systems  

Microsoft Academic Search

Experiments and simulations were performed for helium ion beams to confirm the general validity of the two-dimensional beam direct energy conversion simulation code KUAD (Kyoto University Advanced Dart) for a wide range of beam parameters and to better understand how the performance of beam direct energy recovery is dependent on beam parameters. The experiments compared currents in the 60-to140-mA range

Y. Yamamoto; K. Yoshikawa; H. Toku; T. Haga

1990-01-01

408

Modeling of wind energy conversion system using doubly fed induction generator equipped batteries energy storage system  

Microsoft Academic Search

in this work the model of different parts of the wind energy conversion system using doubly-fed induction generator (DFIG) is set up and implemented in PSCAD\\/EMTDC . The two quadrants DC converter using battery energy storage system is employed for the DC-Link Voltage control in normal and fault operating conditions. To verify the control strategies and Low Voltage ride through

Kone Ibrahima; Chengyong Zhao

2011-01-01

409

Sunlight to electricity: prospects for solar energy conversion by photovoltaics. [Technology assessement of photovoltaic conversion  

Microsoft Academic Search

Economic and technological prospects are assessed for commercial development of photovoltaic material into a viable converter of sunlight into electrical energy. The U.S. energy demand and supply until the year 2000 are defined, and the long-term incentive to utilize solar energy is illustrated. The extent of solar energy falling on the United States in relation to energy demands is treated.

Merrigan

1980-01-01

410

Efficiency evaluation of oxygen enrichment in energy conversion processes  

SciTech Connect

The extent to which energy conversion efficiencies can be increased by using oxygen or oxygen-enriched air for combustion was studied. Combustion of most fuels with oxygen instead of air was found to have five advantages: increases combustion temperature and efficiency, improves heat transfer at high temperatures, reduces nitrous oxide emissions, permits a high ration of exhaust gas recirculation and allows combustion of certain materials not combustible in air. The same advantages, although to a lesser degree, are apparent with oxygen-enriched air. The cost-effectiveness of the process must necessarily be improved by about 10% when using oxygen instead of air before such use could become justifiable on purely economic terms. Although such a modest increase appears to be attainable in real situations, this study ascertained that it is not possible to generally assess the economic gains. Rather, each case requires its own evaluation. For certain processes industry has already proven that the use of oxygen leads to more efficient plant operation. Several ideas for essentially new applications are described. Specifically, when oxygen is used with exhaust gas recirculation in external or internal combustion engines. It appears also that the advantages of pulse combustion can be amplified further if oxygen is used. When burning wet fuels with oxygen, direct steam generation becomes possible. Oxygen combustion could also improve processes for in situ gasification of coals, oil shales, peats, and other wet fuels. Enhanced oil recovery by fire flooding methods might also become more effective if oxygen is used. The cold energy contained in liquid oxygen can be substantially recovered in the low end of certain thermodynamic cycles. Further efforts to develop certain schemes for using oxygen for combustion appear to be justified from both the technical and economic viewpoints.

Bomelburg, H.J.

1983-12-01

411

Demonstration and analysis of combined wind-solar energy conversion systems. Final report  

Microsoft Academic Search

This study has examined the practicality of combined wind-solar energy conversion system (CW-SECS), connected to a common storage facility to produce thermal energy. Coupling a combined wind-solar energy conversion system with an appropriately designed storage capacity should offer the potential to deliver nearly constant levels of energy throughout the year to a specified load. The experimental design combined wind-solar systems

L. Icerman; A. Swift; K. Myers; W. Cargal

1981-01-01

412

The international magnetic fusion energy program  

Microsoft Academic Search

In May of 1988, the long tradition of international cooperation in magnetic fusion energy research culminated in the initiation of design work on the International Thermonuclear Experimental Reactor (ITER). If eventually constructed in the 1990s, ITER would be the world's first magnetic fusion reactor. This paper discusses the background events that led to ITER and the present status of the

1988-01-01

413

A sequential simulation method for the generating capacity adequacy evaluation of small stand-alone wind energy conversion systems  

Microsoft Academic Search

This paper describes a sequential Monte Carlo simulation method for generating capacity adequacy evaluation of small stand-alone wind energy conversion systems containing battery storage. The wind speed, the energy conversion by the wind turbine generator, the equipment reliability and the energy storage facilities are major factors influencing the reliability performance of a wind energy conversion system. Time series models were

Roy Billinton; Bagen

2002-01-01

414

Summary of State-of-the-Art Power Conversion Systems for Energy Storage Applications  

SciTech Connect

The power conversion system (PCS) is a vital part of many energy storage systems. It serves as the interface between the storage device, an energy source, and an AC load. This report summarizes the results of an extensive study of state-of-the-art power conversion systems used for energy storage applications. The purpose of the study was to investigate the potential for cost reduction and performance improvement in these power conversion systems and to provide recommendations for fiture research and development. This report provides an overview of PCS technology, a description of several state-of-the-art power conversion systems and how they are used in specific applications, a summary of four basic configurations for l:he power conversion systems used in energy storage applications, a discussion of PCS costs and potential cost reductions, a summary of the stancku-ds and codes relevant to the technology, and recommendations for future research and development.

Atcitty, S.; Gray-Fenner, A.; Ranade, S.

1998-09-01

415

Magnetic confinement nuclear energy generator  

Microsoft Academic Search

A fusion reactor is described comprising: a sphere defining an inner surface and having a center; superconducting coil means disposed substantially at the center of the sphere for producing a first magnetic field centered within the sphere; coil means disposed circumferentially around the sphere for producing a second magnetic field; means for injecting a gas containing fusible ions into the

Salisbury

1986-01-01

416

Planar High Energy Permanent Magnets.  

National Technical Information Service (NTIS)

The purpose of this program is to demonstrate the feasibility of fabricating cobalt-rare earth permanent magnets by the arc plasma spraying process. Property goals for spray-fabricated magnets consist of a coercive force of 6000 oersteds and a maximum ene...

M. C. Willson R. J. Janowiecki

1973-01-01

417

Refractory Materials for High-Temperature Thermoelectric Energy Conversion.  

National Technical Information Service (NTIS)

Theoretical work of two decades ago adequately explained the transport behavior and effectively guided the development of thermoelectric materials of high conversion efficiencies of conventional semiconductors (e.g., SiGe alloys). The more significant con...

C. Wood D. Emin

1983-01-01

418

Analysis of coal conversion recycle solvents by liquid chromatography with nuclear magnetic resonance detection  

SciTech Connect

The analyses of two coal conversion recycle process solvents, one of them hydrotreated, via high-performance liquid chromatography (HPLC) with a continuous flow nuclear magnetic resonance (NMR) detector are reported. The differences between these samples with reference to the role of the solvent in coal liquefaction are discussed. The LC-/sup 1/H NMR technique characterized the hydrocarbons and aromatic ethers with a level of certainty not possible with conventional detectors. In addition, qualitative GC-MS analysis of off-line LC fractions was performed on the recycle solvent sample. LC-/sup 1/H NMR and LC-GC-MS were found to be complementary for volatile samples. Gel permeation chromatography-/sup 1/H nuclear magnetic resonance (GPC-/sup 1/H NMR) analysis of the recycle solvent sample was not as successful as LC-/sup 1/H NMR since class separation is almost essential for this sample. But the introduction of GPC-/sup 1/H NMR is still of interest since GPC is the most appropriate mode of separation for many samples.

Haw, J.F.; Glass, T.E.; Dorn, H.C.

1981-12-01

419

Permanent Magnet Spiral Motor for Magnetic Gradient Energy Utilization: Axial Magnetic Field  

NASA Astrophysics Data System (ADS)

The Spiral Magnetic Motor, which can accelerate a magnetized rotor through 90% of its cycle with only permanent magnets, was an energy milestone for the 20th century patents by Kure Tekkosho in the 1970's. However, the Japanese company used old ferrite magnets which are relatively weak and an electrically-powered coil to jump start every cycle, which defeated the primary benefit of the permanent magnet motor design. The principle of applying an inhomogeneous, anisotropic magnetic field gradient force Fz = ? cos J dB/dz, with permanent magnets is well-known in physics, e.g., Stern-Gerlach experiment, which exploits the interaction of a magnetic moment with the aligned electron spins of magnetic domains. In this case, it is applied to dB/d? in polar coordinates, where the force F? depends equally on the magnetic moment, the cosine of the angle between the magnetic moment and the field gradient. The radial magnetic field increases in strength (in the attractive mode) or decreases in strength (in the repulsive mode) as the rotor turns through one complete cycle. An electromagnetic pulsed switching has been historically used to help the rotor traverse the gap (detent) between the end of the magnetic stator arc and the beginning (Kure Tekko, 1980). However, alternative magnetic pulse and switching designs have been developed, as well as strategic eddy current creation. This work focuses on the switching mechanism, novel magnetic pulse methods and advantageous angular momentum improvements. For example, a collaborative effort has begun with Toshiyuki Ueno (University of Tokyo) who has invented an extremely low power, combination magnetostrictive-piezoelectric (MS-PZT) device for generating low frequency magnetic fields and consumes ``zero power'' for static magnetic field production (Ueno, 2004 and 2007a). Utilizing a pickup coil such as an ultra-miniature millihenry inductor with a piezoelectric actuator or simply Wiegand wire geometry, it is shown that the necessary power for magnetic field switching device can be achieved in order to deflect the rotor magnet in transit. The Wiegand effect itself (bistable FeCoV wire called ``Vicalloy'') invented by John Wiegand (Switchable Magnetic Device, US Patent No.4,247,601), utilizing Barkhausen jumps of magnetic domains, is also applied for a similar achievement (Dilatush, 1977). Conventional approaches for spiral magnetic gradient force production have not been adequate for magnetostatic motors to perform useful work. It is proposed that integrating a magnetic force control device with a spiral stator inhomogeneous axial magnetic field motor is a viable approach to add a sufficient nonlinear boundary shift to apply the angular momentum and potential energy gained in 315 degrees of the motor cycle.

Valone, Thomas F.

2010-01-01

420

Operando magnetic resonance: monitoring the evolution of conversion and product distribution during the heterogeneous catalytic ethene oligomerisation reaction.  

PubMed

Operando magnetic resonance (MR) spectroscopy has been used to follow an ethene oligomerisation reaction performed at 110 °C, 28 barg over a 1 wt% Ni/SiO2-Al2O3 catalyst. Spectra acquired over the timecourse of the reaction allow the calculation of conversion and product distribution as a function of time-on-stream. PMID:24088715

Roberts, S Tegan; Renshaw, Matthew P; Lutecki, Michal; McGregor, James; Sederman, Andrew J; Mantle, Mick D; Gladden, Lynn F

2013-10-15

421

Biomass conversion Task 4 1988 program of work: International Energy Agency Bioenergy Agreement  

SciTech Connect

For biomass to meet its potential as an energy resource, conversion processes must be available which are both efficient and environmentally acceptable. Conversion can include direct production of heat and electricity as well as production of intermediate gaseous, liquid, and solid fuels. While many biomass conversion processes are commercially available at present, others are still in the conceptual stage. Additional research and development activities on these advanced concepts will be necessary to fully use biomass resources. Ongoing research on biomass conversion processes is being conducted by many nations throughout the world. In an effort to coordinate this research and improve information exchange, several countries have agreed to a cooperative effort through the International Energy Agency's Bioenergy Agreement (IEA/BA). Under this Agreement, Task IV deals specifically with biomass conversion topics. The cooperative activities consists of information exchange and coordination of national research programs on specific topics. The activities address biomass conversion in a systematic manner, dealing with the pretreatment of biomass prior to conversion, the subsequent conversion of the biomass to intermediate fuels or end-product energy, and then the environmental aspects of the conversion process. This document provides an outline of cooperative work to be performed in 1988. 1 fig., 2 tabs.

Stevens, D.J.

1987-12-01

422

Fuzzy logic based indirect vector control of induction generator in Wind Energy Conversion System  

Microsoft Academic Search

In order to meet increasing power demand, taking into account economical and environmental factors, wind energy conversion is gradually gaining interest as a suitable source of renewable energy. The modeling of Wind Energy Conversion System(WECS) is done in MATLAB-SIMULINK. The dynamic d-q model of the induction generator is developed from the fundamentals in a modular approach in simulink. A fuzzy

Y. Sreenivasa Rao; A. Jaya Laxmi

2012-01-01

423

Mode conversion of Langmuir to electromagnetic waves at magnetic field-aligned density inhomogeneities: Simulations, theory, and applications to the solar wind and the corona  

Microsoft Academic Search

Linear mode conversion of Langmuir waves to radiation near the plasma frequency at density gradients is potentially relevant to multiple solar radio emissions, ionospheric radar experiments, laboratory plasma devices, and pulsars. Here we study mode conversion in warm magnetized plasmas using a numerical electron fluid simulation code with the density gradient parallel to the ambient magnetic field B0 for a

Eun-Hwa Kim; Iver H. Cairns; Peter A. Robinson

2008-01-01

424

Challenges and opportunities for photochemists on the verge of solar energy conversion.  

PubMed

Has photochemistry missed the boat on solar energy conversion? Certainly not, but it is time to reach out and make a difference if we do not want to have to choose between feeding our families or our thirst for fuel. Compared to other initiatives, such as biofuels or nuclear fusion, direct conversion of solar energy into electricity or fuels is lagging behind in terms of funding, and this is slowing progress on overcoming critical bottlenecks. This perspective outlines some of the key fundamental issues in solar energy conversion based on organic photovoltaic devices or artificial photosynthesis where being a photochemist can make a difference. PMID:18465006

Chu, Cheng-Che; Bassani, Dario M

2008-04-03

425

The magnesium silicide germanide stannide alloy: A new concept in ocean thermal energy conversion  

Microsoft Academic Search

In devices hitherto used for the direct conversion of heat into electricity, commonly known as ''thermoelectric energy converters'', the efficiency of conversion is appreciably lower than that of conventional reciprocating or rotary heat engines. This low efficiency is brought about by the physical properties of the materials selected for the manufacture of these devices. The materials that are currently being

Nicolaou

1983-01-01

426

Conducting polymer soft actuators based on polypyrrole films---energy conversion efficiency  

Microsoft Academic Search

The electrochemomechanical deformation (ECMD) of conducting polymers can be used to create soft actuators or transducers for the conversion of electric power to mechanical work. Polypyrrole (PPy) films, which were electrodeposited from a methyl benzoate solution of tetrabutylammonium (TBA) trifluoromethansulfonate, TBACF3SO3, were used to investigate the energy conversion efficiency. The films are known to have high tensile strength and to

Keiichi Kaneto; Hisashi Fujisue; Masakatsu Kunifusa; Wataru Takashima

2007-01-01

427

Gain scheduling control of variable-speed wind energy conversion systems using quasi-LPV models  

Microsoft Academic Search

The paper deals with the control of variable-speed wind energy conversion systems (WECS) in the context of linear parameter varying (LPV) systems, a recent formulation of the classic gain scheduling technique. The LPV approach is specially useful in variable-speed WECS control, which is characterized by nonlinear dynamic behavior and opposite objectives. In particular, the following objectives are considered: conversion efficiency

F. D. Bianchi; R. J. Mantz; C. F. Christiansen

2005-01-01

428

Efficient energy conversion from laser to proton beam in a laser-foil interaction  

SciTech Connect

Demonstrated is a remarkable improvement on the energy conversion efficiency from laser to protons in a laser-foil interaction by particle simulations. The total laser-proton energy conversion efficiency becomes 16.7%, although a conventional plane foil target serves a rather low efficiency. In our previous study we found that Al multihole thin-foil target was efficient for the energy conversion from laser to protons [Y. Nodera and S. Kawata, Phys. Rev. E 78, 046401 (2008)], and the energy conversion efficiency was 9.3%. In our 2.5-dimensional particle-in-cell simulations the Al multihole structure is also employed, and the parameters of the Al multihole wing width and length are optimized in the paper. The present results clarify the roles of the target Al hole width and depth in the laser-proton energy conversion. The main physical reason for the enhancement of the conversion efficiency is a reduction of the laser reflection at the target surface area. The optimized multihole foil target provides a remarkable increase in the laser-proton energy conversion efficiency as shown above.

Takahashi, K.; Kawata, S.; Satoh, D.; Barada, D. [Graduate School of Engineering, Utsunomiya University, 7-1-2 Yohtoh, 321-8585 Utsunomiya (Japan); Ma, Y. Y. [Graduate School of Engineering, Utsunomiya University, 7-1-2 Yohtoh, 321-8585 Utsunomiya (Japan); Department of Physics, College of Science, National University of Defense Technology, 410073 Changsha (China); Kong, Q.; Wang, P. X. [Institute of Modern Physics, Fudan University, 200433 Shanghai (China)

2010-09-15

429

Energy conversion and optimal energy management in diesel–electric drivetrains of hybrid-electric vehicles  

Microsoft Academic Search

This paper develops nonlinear models for diesel–electric powertrains used in medium- and heavy-duty hybrid-electric vehicles and describes a new method for designing optimal controllers for highly coupled drivetrains. Current applications of heavily loaded, heavy-duty drives call for the use of comprehensive, innovative ways of handling a large variety of nonlinear phenomena in order to optimize performance and energy conversion, to

Sergey Edward Lyshevski

2000-01-01

430

Legal-institutional arrangements facilitating offshore wind energy conversion systems (WECS) utilization. Final report  

Microsoft Academic Search

Concern for the continuing sufficiency of energy supplies in the U.S. has tended to direct increasing attention to unconventional sources of supply, including wind energy. Some of the more striking proposals for the utilization of wind energy relate to offshore configurations. The legal-institutional arrangements for facilitating the utilization of offshore wind energy conversion systems (WECS) are examined by positioning three

Mayo

1977-01-01

431

HYCSOS chemical heat pump and energy conversion system based on metal hydrides  

Microsoft Academic Search

The Argonne HYCSOS system is a two hydride concept, operating as a chemical heat pump for storage and recovery of thermal energy for heating, cooling and energy conversion. Hydrogen gas is transferred from one hydride bed by solar thermal energy input at a characteristic temperature to a second bed where hydrogen is absorbed and thermal energy is released at another

I. Sheft; D. M. Gruen; G. J. Lamich

1979-01-01

432

Magnetic materials and devices for the 21st century: stronger, lighter, and more energy efficient.  

PubMed

A new energy paradigm, consisting of greater reliance on renewable energy sources and increased concern for energy efficiency in the total energy lifecycle, has accelerated research into energy-related technologies. Due to their ubiquity, magnetic materials play an important role in improving the efficiency and performance of devices in electric power generation, conditioning, conversion, transportation, and other energy-use sectors of the economy. This review focuses on the state-of-the-art hard and soft magnets and magnetocaloric materials, with an emphasis on their optimization for energy applications. Specifically, the impact of hard magnets on electric motor and transportation technologies, of soft magnetic materials on electricity generation and conversion technologies, and of magnetocaloric materials for refrigeration technologies, are discussed. The synthesis, characterization, and property evaluation of the materials, with an emphasis on structure-property relationships, are discussed in the context of their respective markets, as well as their potential impact on energy efficiency. Finally, considering future bottlenecks in raw materials, options for the recycling of rare-earth intermetallics for hard magnets will be discussed. PMID:21294168

Gutfleisch, Oliver; Willard, Matthew A; Brück, Ekkes; Chen, Christina H; Sankar, S G; Liu, J Ping

2010-12-15

433

Advanced-fueled fusion reactors suitable for direct energy conversion  

Microsoft Academic Search

A study of the effect of the magnetic field on the ion trajectories in the two-stage Venetian blind converter has been made; the results suggest that a typical maximum tolerable magnetic field strength is about 0.025 T. Some results of a study of an alternate structural arrangement for the direct converter electrodes in a Tokamak reactor are shown.

A. S. Blum

1976-01-01

434

The energy supply for coronal magnetic structures  

Microsoft Academic Search

This paper examines the source of energy which powers microflares and direct current coronal heating. Motions of the footpoints of loops in the photosphere generate magnetic energy in the corona by increasing the topological complexity of the field. Often these photospheric motions can be regarded as stochastic. 'Stochastic', however, does not imply 'uncorrelated'. Fields and motions can exhibit correlations on

M. A. Berger

1996-01-01

435

United States magnetic fusion energy program  

Microsoft Academic Search

The following topics are discussed: (1) policy; (2) magnetic fusion energy program; (3) physics proof-of-principle programs; (4) major scaling experiments; (5) energy producing experimental reactors: design studies and long lead time technology development; (6) commercialization: reactor designs and systems studies; and (7) enhancement studies. Bibtex entry for this abstract Preferred format for this abstract (see Preferences) Find Similar Abstracts: Use:

S. O. Dean

1978-01-01

436

New electron energy analyzer for magnetized plasmas  

Microsoft Academic Search

A single selecting electrode device for the measurement of electron energy distributions parallel to a strong magnetic field in a plasma is described. A series of parallel plates eliminates ion entry into the analyzer and selectively retards electrons for energy analysis. The device was tested in a hot cathode discharge in the University of Maryland Mirror Machine. Results compare favorably

D. N. Arion; R. F. Ellis

1982-01-01

437

Thermal conversion of hydrocarbons with low energy air preheater  

SciTech Connect

Combustion air, prior to being introduced into the cracking furnace in a hydrocarbon pyrolytic conversion and separation system, is preheated by employing bottom pumparound, top pumparound and/or quench water streams diverting from the primary fractionator externally connected to the pyrolysis reactor in order to optimize the thermal efficiency of the overall process.

Bacsik, G.J.

1982-03-23

438

Thermal conversion of hydrocarbons with low energy air preheater  

Microsoft Academic Search

Combustion air, prior to being introduced into the cracking furnace in a hydrocarbon pyrolytic conversion and separation system, is preheated by employing bottom pumparound, top pumparound and\\/or quench water streams diverting from the primary fractionator externally connected to the pyrolysis reactor in order to optimize the thermal efficiency of the overall process.

Bacsik

1982-01-01

439

Energy contents and conversion factors for sea lion's prey1  

Microsoft Academic Search

In order to understand the effect the diet of Steller sea lions may have had on their decline in the North West Pacific and the Gulf of Alaska, a database of the energetic contents of Steller sea lion's prey was compiled and added to the database of general conversions used by the students and researchers at the Fisheries Centre. Multiple

Geneviève Cauffopé; Sheila J. J. Heymans

2005-01-01

440

Proceedings of the 26th intersociety energy conversion engineering conference  

SciTech Connect

This volume covers the following topics: aerospace power systems; advanced aerospace power concepts, aircraft power, analysis of PMAD performance, automation, burst and pulse power, environmental issues, power circuits, power components simulation, solar dynamics, solar dynamics, solar dynamics conversion cycle, space design of PMAD systems, space environmental effects, space high voltage environment, space nuclear systems, space power automation.

Not Available

1991-01-01

441

A Conversation about the Bethe Free Energy and Sum-Product  

Microsoft Academic Search

This discussion document records an email conversation in preparation for the Triestemeeting.BackgroundThe result that `belief propagation xed-points are zero gradient points of the Bethe free energy\\

David J. c. Mackay; Jonathan S. Yedidia; William T. Freeman; Yair Weiss

2001-01-01

442

Solid Waste Energy Conversion Project, Reedy Creek Utilities Demonstration Plant: Environmental Assessment.  

National Technical Information Service (NTIS)

The Solid Waste Energy Conversion (SWEC) facility proposed would produce high-temperature hot water from urban refuse and would also provide a demonstration pilot-plant for the proposed Transuranic Waste Treatment Facility (TWTF) in Idaho. The SWEC projec...

1980-01-01

443

Heat Exchanger Cleaning in Support of Ocean Thermal Energy Conversion (OTEC) - Electronics Subsystems.  

National Technical Information Service (NTIS)

Electronics systems supporting the development of biofouling countermeasures for Ocean Thermal Energy Conversion (OTEC) are described. Discussed are the thermistor/thermopile amplifiers, heaters, flowmeters, temperature measurement, control systems for ch...

D. F. Lott

1980-01-01

444

Municipal Solid Waste Energy Conversion Study on Guam and American Samoa.  

National Technical Information Service (NTIS)

In the Pacific Islands of Guam and Tutuila in American Samoa, conversion of municipal solid waste to useable energy forms - principally electricity but possibly steam - may hold promise for reducing economic dependence on imported petroleum. A secondary b...

1984-01-01

445

Vacuum Deaeration for Ocean Thermal-Energy-Conversion Open-Cycle Applications.  

National Technical Information Service (NTIS)

Seawater deaeration is a process affecting almost all proposed Ocean Thermal Energy Conversion (OTEC) open-cycle power systems. If the noncondensable dissolved air is not removed from a power system, it will accumulate in the condenser, reduce the effecti...

A. Golshani F. C. Chen

1981-01-01

446

Material Problems for High-Temperature, High-Power Space Energy-Conversion Systems.  

National Technical Information Service (NTIS)

High-temperature, high-power space energy-conversion systems follow an evolutionary path through continually expanding materials frontiers. Exponential growth trends point to requirements for ultimate alloys comprising the most refractory metals and metal...

M. L. Ramalingam D. L. Jacobson J. F. Morris S. Snir

1984-01-01

447

Kinematic Stirling Engine as an Energy Conversion Subsystem for Paraboloidal Dish Solar Thermal Power Plants.  

National Technical Information Service (NTIS)

The potential of a suitably designed and economically manufactured Stirling engine as the energy conversion subsystem of a paraboloidal dish-Stirling solar thermal power module has been estimated. Results obtained by elementary cycle analyses have been sh...

J. M. Bowyer

1984-01-01

448

The Kinematic Stirling Engine as an Energy Conversion Subsystem for Paraboloidal Dish Solar Thermal Plants.  

National Technical Information Service (NTIS)

The potential of a suitably designed and economically manufactured Stirling engine as the energy conversion subsystem of a paraboloidal dish-Stirling solar thermal power module was estimated. Results obtained by elementary cycle analyses were shown to mat...

J. M. Bowyer

1984-01-01

449

Program Plan: Systems Definition Project of the Energy Research and Developnent Administration's National Photovoltaic Conversion Program.  

National Technical Information Service (NTIS)

This Program Plan describes the Systems Definition Project to be accomplished by Sandia Laboratories for the Energy Research and Development Administration's (ERDA) National Photovoltaic Conversion Program. The Program Plan includes the scope and objectiv...

1975-01-01

450

The practical experience of a total conversion to high energy electron beam processing  

NASA Astrophysics Data System (ADS)

The total conversion of a manufacturing site to a new sterilisation method, high energy electron beam, combined with the rearrangement of the concerned assortment of products is a vast program. The result is a modern and efficient sterilisation tool.

Descamps, Th.

1995-02-01

451

Role of thermochemical conversion in livestock waste-to-energy treatments: Obstacles and opportunities  

Technology Transfer Automated Retrieval System (TEKTRAN)

Integrating thermochemical conversion (TCC) technologies with current animal waste treatment practices can treat and reduce quantities of manure from consolidated animal feeding operations. Additionally, TCC technologies can produce value-added, renewable energy products. These products can meet hea...

452

Regulations to Implement Public Law 96-320, The Ocean Thermal Energy Conversion Act of 1980.  

National Technical Information Service (NTIS)

The regulations discussed in this analysis implement Public Law 96-320, the Ocean Thermal Energy Conversion (OTEC) Act of 1980, by establishing a regulatory system which will permit and encourage commercial development of OTEC technology. In addition the ...

1981-01-01

453

The special features of heat conversion into work in solar cell energy reemission  

Microsoft Academic Search

The absorption of radiant energy in solar cells is divided into parallel reversible and irreversible circular processes. Their\\u000a fractions correlate with the known thermodynamic limits of the efficiency of heat conversion into work provided the conversion\\u000a of solar energy is divided into antenna and work processes. (An analogue of antenna processes is the selective absorption\\u000a of solar radiation by pigment

V. I. Laptev

2006-01-01

454

Photolysis of water as a solar energy conversion process - An assessment  

Microsoft Academic Search

One of the less conventional solar-energy conversion methods is the photocatalytic decomposition of H2O to generate H2 and O2 directly. This paper presents an assessment of photolysis of water by sunlight. Calculations are used to establish efficiency upper limits for this type of energy-conversion method using three different photocatalysts: compound salts, compound semiconductors, and photosynthetic dyes. The efficiencies were estimated

S. N. Paleocrassas

1975-01-01

455

Energy resolution of liquid scintillator for ?-particles and internal conversion electrons at lower temperatures  

Microsoft Academic Search

The energy resolution of -particles from241Am,222Rn,218Po and214Po and internal conversion electrons from131mXe with a liquid scintillation system has been studied at temperatures from 13 °C to –65 °C. At lower temperatures the liquid scintillation system has shown to give better energy resolutions both for -particles and internal conversion electrons compared with the values obtained at ordinary temperature. The phenomena were

Y. Homma; Y. Murase

1987-01-01

456

Expert opinion on wind energy conversion systems designed by Hermann Honnef  

Microsoft Academic Search

The plans by Hermann Honnef for using wind power by means of large-scale wind energy conversion systems with regard to the proposed technical design and their presently expected cost-effectiveness were assessed. The conclusion that the findings and experience of the past few decades have shown that this type of wind energy conversion systems using contra-rotating, multi-blade turbines are not economical.

H. Doerner

1977-01-01

457

Spectral-selective surfaces for the thermal conversion of solar energy  

Microsoft Academic Search

The thesis covers the study of spectral-selective surfaces for flat plate collectors and the measurement of the main radiation quantities in the direct conversion of solar into thermal energy, and it is aimed to develop high radiant efficiency material. Solar energy conversion processes and selective-absorber surfaces, the definitions and calculations of radiation and optical quantities related to the spectral-selective surfaces

M. van der Leij

1979-01-01

458

High Energy Utilization, Co-Generation Nuclear power Plants With Static Energy Conversion  

SciTech Connect

In addition to being cost effective, very small nuclear power plants with static energy conversion could meet the needs and the energy mix in underdeveloped countries and remote communities, which may include electricity, residential and industrial space heating, seawater desalination, and/or high temperature process heat or steam for industrial uses. These plants are also an attractive option in naval, marine, and undersea applications, when the absence of a sound signature is highly desirable. An Analysis is performed of Gas Cooled Reactor (CGR) and Liquid Metal Cooled Reactor (LMR), very small nuclear power plants with static energy conversion, using a combination of options. These include Alkali Metal Thermal-to-Electric Converters (AMTECs) and both single segment and segmented thermoelectric converters. The total energy utilization of these plants exceeds 88%. It includes the fraction of the reactor's thermal power converted into electricity and delivered to the Grid at 6.6 kVA and those used for residential and industrial space heating at {approx}370 K, seawater desalination at 400 K, and/or high temperature process heat or steam at {approx}850 K. In addition to its inherently high reliability, modularity, low maintenance and redundancy, static energy conversion used in the present study could deliver electricity to the Grid at a net efficiency of 29.5%. A LMR plant delivers 2-3 times the fraction of the reactor thermal power converted into electricity in a GCR plant, but could not provide for both seawater desalination and high temperature process heat/steam concurrently, which is possible in GCR plants. The fraction of the reactor's thermal power used for non-electrical power generation in a GCR plant is {approx} 10 - 15% higher than in a LMR plant. (authors)

El-Genk, Mohamed S.; Tournier, Jean-Michel P. [Institute for Space and Nuclear Power Studies and Chemical and Nuclear Engineering Department, The University of New Mexico, Albuquerque, NM (United States)

2002-07-01

459

Magnetic fusion energy and space development  

Microsoft Academic Search

Large-scale space development will require efficient propulsion and power systems. Magnetic fusion energy conceptual designs are surveyed and indicate that fusion could provide attractive solutions to this need. Using deuterium and helium-3 as fuel gives fusion products that are primarily charged particles and could be guided by magnetic fields to allow high efficiency. The main 21st-century source of 3 He

John F. Santarius

1989-01-01

460

Phases in the Deployment of Offshore Wind Energy Conversion Systems (WECS) Configurations to Legal-Institutional Implications of Wind Energy Conversion Systems. Appendix A.  

National Technical Information Service (NTIS)

The basic sequence of functions and actions which will be or may be involved in the deployment of an offshore wind energy conversion system (WECS) installation is presented. Certain project configurations are posited in order to examine on a provisional b...

1977-01-01

461

Magnets for high energy colliders  

SciTech Connect

The problem of producing, preserving and stably colliding low emittance bunches for long periods of time is a formidable problem involving questions of jitter, dynamic alignment and reproducibility associated with magnetic and mechanically hysteresis. Permanent magnets provide ideal solutions for lower capital and operating costs. Because they are light in weight, compact and require no power or cooling they are easy to use, stable and uniquely reliable. With their low permeability this implies a minimal impact on the surrounding environment and vice versa. For example, they are ideal for final focus systems embedded in particle detectors with strong solenoidal fields while their strength and compactness minimizes the solid angle they subtend around the interaction point (IP) as well as their target thickness along the beam line. We discuss calculations there /rvec B/ is a nonlinear, anisotropic function of /rvec H/. The results explain discrepancies observed measurement and calculation of permanent magnet systems and indicate good multipoles are possible with far higher strengths than previously obtained. We extend previous calculations on the obtainable gradients for different types of quadrupoles down to 1 mm bore radii where 2000 T/m appears possible with conventional designs and available materials. We discuss why much higher gradients are possible by the same means. Additional specifications for PM manufacturers are recommended. 14 refs., 5 figs.

Spencer, J.; Stucki, H.

1989-03-01

462

Energy conversion analysis and performance research on a cone-type dielectric electroactive polymer generator  

Microsoft Academic Search

As a type of intelligent material, dielectric electroactive polymer (DEAP) has shown considerable promise for energy harvesting purposes as well as in actuator mode. Theoretical analysis on DEAP generators is important to guide the optimization and design of a DEAP generator. In this paper, firstly, four working phases of a DEAP generator and energy conversion between mechanical energy input and

Yinlong Zhu; Huaming Wang; Dongbiao Zhao; Jun Zhao

2011-01-01

463

Power transfer capability improvement of an induction generator wind energy conversion system  

Microsoft Academic Search

Wind energy is considered the most viable proposition among the renewable energy options. Of various Wind Energy Conversion Systems (WECS), fixed speed induction generator based WECS directly connected to the grid is the cheapest and simplest option and has the largest market share. This type of WECS does not require any power electronic interface to allow the grid connection unlike

Susanne Sugiarto; Syed Islam; Ahmed Abu-Siada

2009-01-01

464

Systematic method for oxidation pond conversion for the production of site specific energy sources  

Microsoft Academic Search

Primary sources of solar derived biomass (sugarcane, wood, and aquatic plants), are of considerable future importance as energy producing substrates. The waste products of agriculture and husbandry represent a viable and potentially significant energy source, also. Solar energy, produced photosynthetically, is available not only by combustion or conversion of plant materials, but also by utilizing metabolic products of succeeding trophic

E. Werner; T. Rodriguez

1981-01-01

465

Using the condenser effluent from a nuclear power plant for Ocean Thermal Energy Conversion (OTEC)  

Microsoft Academic Search

There has been increasing interest in clean energy over past few years. Ocean Thermal Energy Conversion (OTEC) power plants have been examined as a viable option for supplying clean energy. This paper evaluated the thermodynamic performance of the OTEC power system. Computer simulation programs were developed under the same conditions but with various working fluids for a closed system, a

Nam Jin Kim; Kim Choon Ng; Wongee Chun

2009-01-01

466

Potential Impacts of Hydrokinetic and Wave Energy Conversion Technologies on Aquatic Environments  

Microsoft Academic Search

A new generation of hydropower technologies, the kinetic hydro and wave energy conversion devices, offers the possibility of generating electricity from the movements of water, without the need for dams and diversions. The Energy Policy Act of 2005 encouraged the development of these sources of renewable energy in the United States, and there is growing interest in deploying them globally.

Glenn Cada; James Ahlgrimm; Michael Bahleda; Tom Bigford; Stefanie Damiani Stavrakas; Douglas Hall; Russell Moursund; Michael Sale

2007-01-01

467

Optimum control strategies in energy conversion of PMSG wind turbine system without mechanical sensors  

Microsoft Academic Search

The amount of energy obtained from a wind energy conversion system (WECS) depends not only on the characteristics of the wind regime at the site, but it also depends on the control strategy used for the WECS. In order to determine the gain in energy derived from one concept as compared against another, models of several autonomous WECS have been

Kelvin Tan; Syed Islam

2004-01-01

468

Electric utility application of wind energy conversion systems on the island of Oahu  

Microsoft Academic Search

This wind energy application study was performed by The Aerospace Corporation for the Wind Systems Branch of the Department of Energy. The objective was to identify integration problems for a Wind Energy Conversion System (WECS) placed into an existing conventional utility system. The integration problems included environmental, institutional and technical aspects as well as economic matters, but the emphasis was

C. A. Lindley; W. C. Melton

1979-01-01

469

Modeling and performance anyalysis of synchronous based Wind Energy Conversion System  

Microsoft Academic Search

Wind Energy Conversion Systems are wind generators that convert aerodynamic energy from the wind to electrical energy at the load. The increase in wind generation is the result of an increasing demand for electricity, with infinite availability and the pollution free natures of wind as a prime motivator for wind generation. WECS exist in a variety of technologies but this

Kulisha W. Appadoo; S. P. Chowdhury

2011-01-01

470

High Temperature Fusion Reactor Cooling Using Brayton Cycle Based Partial Energy Conversion  

Microsoft Academic Search

For some future space power systems using high temperature nuclear heat sources most of the output energy will be used in other than electrical form, and only a fraction of the total thermal energy generated will need to be converted to electrical work. The paper describes the conceptual design of such a ``partial energy conversion'' system, consisting of a high

Albert J. Juhasz; Jerzy T. Sawicki

2004-01-01

471

New power-conditioning systems for superconducting magnetic energy storage  

NASA Astrophysics Data System (ADS)

This dissertation presents the development of new power-conditioning systems for superconducting magnetic energy storage (SMES), which can regulate fast and independently the active and reactive powers demanded in the ac network. Three new power-conditioning systems were developed through a systematic approach to match the requirements of the superconducting coil and the ac power network. Each of these new systems is composed of ten 100-MW modules connected in parallel to handle the large current through the superconducting coil. The first system, which was published in the IEEE Transactions on Energy Conversion, consists of line-commutated 24-pulse converter, a thyristor-switched tap-changing transformer, and a thyristor-switched capacitor bank. The second system, which was accepted for publication in the IEEE Transactions on Energy Conversion, consists of a 12-pulse GTO (gate turn-off thyristor) converter and a thyristor-switched tap-changing transformer. The third system, which was submitted to the International Journal of Energy System, consists of a dc chopper and a voltage-source PWM (pulse width modulation) converter. The operational concept of each new system is verified through mathematical analyses and computer simulations. The dynamic interaction of each new system with the ac network and the superconducting coil is analyzed using a simulation model with EMTP (electro-magnetic transients program). The analysis results prove that each new system is feasible and realizable. Each system can regulate the active and reactive powers of the utility network rapidly and independently, and each offer a significant reduction of the system rating by reducing the reactive power demand in the converter. Feasible design for each new system was introduced using a modular design approach based on the 1000 MW/5000 MWH plant, incorporating commercially available components and proven technologies.

Han, Byung Moon

1992-06-01

472

New power-conditioning systems for superconducting magnetic energy storage  

SciTech Connect

This dissertation presents the development of new power-conditioning systems for superconducting magnetic energy storage (SMES), which can regulate fast and independently the active and reactive powers demanded in the ac network. Three new power-conditioning systems were developed through a systematic approach to match the requirements of the superconducting coil and the ac power network. Each of these new systems is composed of ten 100-MW modules connected in parallel to handle the large current through the superconducting coil. The first system, which was published in the IEEE Transactions on EnergyConversion, consists of line-commutated 24-pulse converter, a thyristor-switched tap-changing transformer, and a thyristor-switched capacitor bank. The second system, which was accepted for publication in the IEEE Transactions on Energy Conversion, consists of a 12-pulse GTO (gate turn-off thyristor) converter and a thyristor-switched tap-changing transformer. The third system, which was submitted to the International Journal of Energy System, consists of a dc chopper and a voltage-source PWM (pulse width modulation) converter. The operational concept of each new system is verified through mathematical analyses and computer simulations. The dynamic interaction of each new system with the ac network and the superconducting coil is analyzed using a simulation model with EMTP (electro-magnetic transients program). The analysis results prove that each new system is feasible and realizable. Each system can regulate the active and reactive powers of the utility network rapidly and independently, and each offer a significant reduction of the system rating by reducing the reactive power demand in the converter. Feasible design for each new system was introduced using a modular design approach based on the 1000 MW/5000 MWH plant, incorporating commercially available components and proven technologies.

Han, B.M.

1992-01-01

473

Feasible utility scale superconducting magnetic energy storage system  

NASA Astrophysics Data System (ADS)

This paper presents the latest design features and estimated costs of a 5000 MWh/1000 MW Superconducting Magnetic Energy Storage (SMES) plant. SMES is proposed as a commercially viable technology for electric utility load leveling. The primary advantage of SMES over other electrical energy storage technologies is its high net roundtrip efficiency. Other features include rapid availability and low maintenance and operating costs. Economic comparisons are made with other energy storage options and with gas turbines. In a diurnal load leveling application, a superconducting coil can be charged from the utility grid during off-peak hours. The ac grid is connected to the dc magnetic coil through a power conversion system that includes an inverter/rectifier. Once charged, the superconducting coil conducts current, which supports an electromagnetic field, with virtually no losses. During hours of peak load, the stored energy is discharged to the grid by reversing the charging process. The principle of operation of a SMES unit is shown. For operation in the superconducting mode, the coil is maintained at extremely low temperature by immersion in a bath of liquid helium.

Loyd, R. J.; Schoenung, S. M.; Nakamura, T.; Lieurance, D. W.; Hilal, M. A.; Rogers, J. D.; Purcell, J. R.; Hassenzahl, W. V.

474

Energy analyses applied to an ocean thermal energy conversion (OTEC) system and an offshore windpower system (OWPS)  

Microsoft Academic Search

Energy analyses were applied to an ocean thermal energy conversion (OTEC) system and an offshore windpower system (OWPS) designed to supply the 1990 energy demands of the New England region. The OTEC system would involve 106,400 Mw powerplants off the Carolina coast; the OWPS system involves 81 units. Both systems use hydrogen generated onsite as an energy storage medium and

I. C. G

1979-01-01

475

DIRECT ENERGY CONVERSION FISSION REACTOR FOR THE PERIOD APRIL 1, 2002 THROUGH JUNE 30, 2002  

SciTech Connect

Direct energy conversion is the only potential means for producing electrical energy from a fission reactor without the Carnot efficiency limitations. This project was undertaken by Sandia National Laboratories, Los Alamos National Laboratories, The University of Florida, Texas A&M University and General Atomics to explore the possibilities of direct energy conversion. Other means of producing electrical energy from a fission reactor, without any moving parts, are also within the statement of proposed work. This report documents the efforts of General Atomics. Sandia National Laboratories, the lead laboratory, provides overall project reporting and documentation.

L.C. BROWN

2002-06-30

476

Gravity of magnetic stresses and energy  

SciTech Connect

In the framework of designing laboratory tests of relativistic gravity, we investigate the gravitational field produced by the magnetic field of a solenoid. Observing this field might provide a means of testing whether stresses gravitate as predicted by Einstein's theory. A previous study of this problem by Braginsky, Caves, and Thorne predicted that the contribution to the gravitational field resulting from the stresses of the magnetic field and of the solenoid walls would cancel the gravitational field produced by the mass-energy of the magnetic field, resulting in a null magnetically generated gravitational force outside the solenoid. They claim that this null result, once proved experimentally, would demonstrate the stress contribution to gravity. We show that this result is incorrect, as it arises from an incomplete analysis of the stresses, which neglects the axial stresses in the walls. Once the stresses are properly evaluated, we find that the gravitational field outside a long solenoid is in fact independent of Maxwell and material stresses, and it coincides with the Newtonian field produced by the linear mass distribution equivalent to the density of magnetic energy stored in a unit length of the solenoid. We argue that the gravity of Maxwell stress can be directly measured in the vacuum region inside the solenoid, where the Newtonian noise is absent in principle, and the gravity generated by Maxwell stresses is not screened by the negative gravity of magnetic-induced stresses in the solenoid walls.

Bimonte, Giuseppe; Calloni, Enrico; Rosa, Luigi [Dipartimento di Scienze Fisiche, Universita di Napoli Federico II, Complesso Universitario MSA, Via Cintia I-80126 Naples (Italy) and INFN, Sezione di Napoli, Naples (Italy)

2008-02-15

477

Application of Nuclear Energy to Bitumen Upgrading and Biomass Conversion  

SciTech Connect

Key drivers for the increasing use of nuclear energy are the need to mitigate global warming and the requirement for energy security. Nuclear energy can be applied not only to generate electricity but also as a heat source. Moreover, nuclear energy can be applied for hydrogen as well as water production. The application of nuclear energy to oil processing and biomass production is studied in this paper. (authors)

Mamoru Numata; Yasushi Fujimura [JGC Corporation (Japan); Takayuki Amaya [Ministry of Education, Culture, Sports, Science and Technology - MEXT, Japan 2-5-1 Marunouchi Chiyoda-ku, Tokyo 100-8959 (Japan); Masao Hori [Nuclear Systems Association, 1-7-6 Toranomon Tokyo, 105-0001 (Japan)

2006-07-01

478

High-temperature inert gas plasma magnetohydrodynamic energy conversion by using linear-shaped Faraday-type channel  

NASA Astrophysics Data System (ADS)

We describe high-density magnetohydrodynamic (MHD) energy conversion in a high-temperature seed-free argon plasma, for which a compact linear-shaped Faraday-type MHD electrical power generator is used. Short-time-duration single-pulse shock-tunnel-based experiments demonstrate the MHD energy conversion with varying total inflow temperature up to 9000 K and applied magnetic-flux density up to 4.0 T. The high-temperature plasma is transformed from the thermal-equilibrium state at the entrance to the weak-nonequilibrium state in the supersonic MHD channel. The discharge structure is reasonably homogeneous without suffering from serious streamer development. The power generation performance is monotonically improved by increasing total inflow temperature and strength of magnetic field. The enthalpy extraction efficiency of 13.1% and overall power density of 0.16 GW/m3 are attained. The local power density at the middle of the channel reaches 0.24 GW/m3.

Murakami, Tomoyuki; Zhuang, Yunqin; Okuno, Yoshihiro

2013-02-01

479

TPV conversion of nuclear energy for space applications  

SciTech Connect

This paper explores the possibility of achieving high conversion efficiencies in a closed loop TPV system by replacing the typical combustion thermal source with a nuclear thermal source such as a high temperature gas cooled reactor. Possible applications are nuclear electric propulsion, long-term power for mission support systems, and terrestrial base nuclear power systems. The emitter portion of the system utilizes a novel low temperature processing technique, while the collector portion of the system utilizes a holographic concentrator/spectral splitter to reduce cell area and remove off-band emissions. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Regan, T.M.; Martin, J.G. [Department of Chemical and Nuclear Engineering, University of Massachusetts Lowell, Massachusetts 01854 (United States); Riccobono, J. [Northeast Photosciences, Hollis, New Hampshire (United States)

1995-01-05

480

Toroidal constant-tension superconducting magnetic energy storage units  

DOEpatents

A superconducting magnetic energy storage unit is provided in which the magnet is wound in a toroidal fashion such that the magnetic field produced is contained only within the bore of the magnet, and thus producing a very low external field. The superconducting magnet includes a coolant channel disposed through the wire. The bore of the magnet comprises a storage volume in which cryogenic coolant is stored, and this volume supplies the coolant to be delivered to the coolant in the magnet.

Herring, J.S.

1990-10-26

481

Progress in magnetic fusion energy research  

Microsoft Academic Search

The remarkable scientific progress that has been made in the Magnetic Fusion Energy Program since its inception 40 years ago is reviewed. This formalized international collaborative effort of design and development for a 1000-MW experimental reactor (ITER) has been entered into by the United States, Russia, Japan, and the European Community. In the United States, a national project to build

Keith I. Thomassen

1993-01-01

482

Charting the roadmap to magnetic fusion energy  

Microsoft Academic Search

With the ITER era now well underway, the fusion community is considerin g the next major ste ps in magnetic fusion energy (MFE) development. It follows that there is heightened interest worldwide in understanding the roadma p to commercial MFE. In reality, there is no unique roadmap. An important differentiator among possible pathways is risk, i.e. the risks accepted in

G. H. Neilson; R. Betti; D. Gates; C. Kessel; J. Menard; S. Prager; S. Scott; M. Zarnstorff

2011-01-01

483

Strain energy minimization in SSC magnet winding  

Microsoft Academic Search

Differential geometry provides a natural family of coordinate systems, the Frenet frame, in which to specify the geometric properties of a magnet winding. By a modification of the Euler-Bernoulli thin rod model, the strain energy is defined with respect to this frame. Then, it is minimized by a direct method from the calculus of variations. The mathematics, its implementation in

J. M. Cook

1991-01-01

484

Microwave generation for magnetic fusion energy applications  

Microsoft Academic Search

This progress report encompasses work on three separate projects, all related to developing sources for electron cyclotron resonance heating of magnetic fusion plasmas. The report is therefore divided into three parts as follows: free electron lasers with small period wigglers; theory and modeling of high frequency, high power gyrotron operation; and depressed collectors for energy recovery in gyrotrons. Task A

T. M. Antonsen Jr.; W. W. Destler; V. L. Granatstein; B. Levush; I. D. Mayergoyz

1991-01-01

485

Status of the Magnetic Fusion Energy Programme  

Microsoft Academic Search

Fusion reactor level plasma parameters have been achieved in experimental devices during the last decade. Energy breakeven is expected in the larger plasma confinement devices that have recently begun or are about to begin operation with the goal of demonstrating that magnetic fusion systems are scientifically feasible. The present status of research in torodial and mirror systems is reviewed. Specifically,