Science.gov

Sample records for absolute energy conversion

  1. Absolute instability from linear conversion of counter-propagating positive and negative energy waves

    SciTech Connect

    Kaufman, A.N.; Brizard, A.J.; Morehead, J.J.; Tracy, E.R.

    1997-12-31

    The resonant interaction of a negative-energy wave with a positive-energy wave gives rise to a linear instability. Whereas a single crossing of rays in a nonuniform medium leads to a convectively saturated instability, we show that a double crossing can yield an absolute instability.

  2. Redetermining CEBAF's Absolute Energy

    NASA Astrophysics Data System (ADS)

    Su, Tong; Jlab Marathon Collaboration

    2015-04-01

    With the upgrade of the Jefferson Lab accelerator (CEBAF) from 6 GeV max energy to 12 GeV, all the dipole magnets in the machine were refurbished. Most of them were switched from open c-shaped to closed h-shaped by adding extra iron. With these upgraded magnets, the energy calibration of the accelerator needed to be redetermined. We will show how an extra external dipole, which is run in series with those in the machine, helps us cross check the current in the magnets as well as precisely map out the integral field for any machine setting. Using knowledge of the relative performance of the dipoles as well as the bend angle into the Hall, has allowed us to already determine a 4th pass 7 GeV beam to better than 7 MeV. In the future, we will use g-2 spin precession as a second independent energy determination. This work is supported by Kent State University, NSF Grant PHY-1405814, and DOE Contract DE-AC05-06OR23177 (JLab).

  3. Direct Conversion of Energy.

    ERIC Educational Resources Information Center

    Corliss, William R.

    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…

  4. Determination of absolute internal conversion coefficients using the SAGE spectrometer

    NASA Astrophysics Data System (ADS)

    Sorri, J.; Greenlees, P. T.; Papadakis, P.; Konki, J.; Cox, D. M.; Auranen, K.; Partanen, J.; Sandzelius, M.; Pakarinen, J.; Rahkila, P.; Uusitalo, J.; Herzberg, R.-D.; Smallcombe, J.; Davies, P. J.; Barton, C. J.; Jenkins, D. G.

    2016-03-01

    A non-reference based method to determine internal conversion coefficients using the SAGE spectrometer is carried out for transitions in the nuclei of 154Sm, 152Sm and 166Yb. The Normalised-Peak-to-Gamma method is in general an efficient tool to extract internal conversion coefficients. However, in many cases the required well-known reference transitions are not available. The data analysis steps required to determine absolute internal conversion coefficients with the SAGE spectrometer are presented. In addition, several background suppression methods are introduced and an example of how ancillary detectors can be used to select specific reaction products is given. The results obtained for ground-state band E2 transitions show that the absolute internal conversion coefficients can be extracted using the methods described with a reasonable accuracy. In some cases of less intense transitions only an upper limit for the internal conversion coefficient could be given.

  5. Energy conversion alternatives study

    NASA Technical Reports Server (NTRS)

    Shure, L. T.

    1979-01-01

    Comparison of coal based energy systems is given. Study identifies and compares various advanced energy conversion systems using coal or coal derived fuels for baselaoad electric power generation. Energy Conversion Alternatives Study (ECAS) reports provede government, industry, and general public with technically consistent basis for comparison of system's options of interest for fossilfired electric-utility application.

  6. Evaluating Energy Conversion Efficiency

    NASA Technical Reports Server (NTRS)

    Byvik, C. E.; Smith, B. T.; Buoncristiani, A. M.

    1983-01-01

    Devices that convert solar radiation directly into storable chemical or electrical energy, have characteristic energy absorption spectrum; specifically, each of these devices has energy threshold. The conversion efficiency of generalized system that emcompasses all threshold devices is analyzed, resulting in family of curves for devices of various threshold energies operating at different temperatures.

  7. Ocean thermal energy conversion

    SciTech Connect

    Avery, W.H.

    1983-03-17

    A brief explanation of the Ocean Thermal Energy Conversion (OTEC) concept and an estimate of the amount of energy that can be produced from the ocean resource without introducing environmental concerns are presented. Use of the OTEC system to generate electric power and products which can replace fossil fuels is shown. The OTEC program status and its prospects for the future are discussed.

  8. Session: Energy Conversion

    SciTech Connect

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

    1992-01-01

    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.

  9. Laser energy conversion

    NASA Technical Reports Server (NTRS)

    Jalufka, N. W.

    1989-01-01

    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.

  10. Solar energy conversion.

    SciTech Connect

    Crabtree, G. W.; Lewis, N. S.

    2008-03-01

    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

  11. Mechanochemical Energy Conversion

    ERIC Educational Resources Information Center

    Pines, E.; And Others

    1973-01-01

    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)

  12. Electromechanical Energy Conversion.

    ERIC Educational Resources Information Center

    LePage, Wilbur R.

    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)

  13. Microbial Energy Conversion

    SciTech Connect

    Buckley, Merry; Wall, Judy D.

    2006-10-01

    The American Academy of Microbiology convened a colloquium March 10-12, 2006, in San Francisco, California, to discuss the production of energy fuels by microbial conversions. The status of research into various microbial energy technologies, the advantages and disadvantages of each of these approaches, research needs in the field, and education and training issues were examined, with the goal of identifying routes for producing biofuels that would both decrease the need for fossil fuels and reduce greenhouse gas emissions. Currently, the choices for providing energy are limited. Policy makers and the research community must begin to pursue a broader array of potential energy technologies. A diverse energy portfolio that includes an assortment of microbial energy choices will allow communities and consumers to select the best energy solution for their own particular needs. Funding agencies and governments alike need to prepare for future energy needs by investing both in the microbial energy technologies that work today and in the untested technologies that will serve the world’s needs tomorrow. More mature bioprocesses, such as ethanol production from starchy materials and methane from waste digestors, will find applications in the short term. However, innovative techniques for liquid fuel or biohydrogen production are among the longer term possibilities that should also be vigorously explored, starting now. Microorganisms can help meet human energy needs in any of a number of ways. In their most obvious role in energy conversion, microorganisms can generate fuels, including ethanol, hydrogen, methane, lipids, and butanol, which can be burned to produce energy. Alternatively, bacteria can be put to use in microbial fuel cells, where they carry out the direct conversion of biomass into electricity. Microorganisms may also be used some day to make oil and natural gas technologies more efficient by sequestering carbon or by assisting in the recovery of oil and

  14. Wind energy conversion system

    DOEpatents

    Longrigg, Paul

    1987-01-01

    The wind energy conversion system includes a wind machine having a propeller connected to a generator of electric power, the propeller rotating the generator in response to force of an incident wind. The generator converts the power of the wind to electric power for use by an electric load. Circuitry for varying the duty factor of the generator output power is connected between the generator and the load to thereby alter a loading of the generator and the propeller by the electric load. Wind speed is sensed electro-optically to provide data of wind speed upwind of the propeller, to thereby permit tip speed ratio circuitry to operate the power control circuitry and thereby optimize the tip speed ratio by varying the loading of the propeller. Accordingly, the efficiency of the wind energy conversion system is maximized.

  15. Energy conversion system

    DOEpatents

    Murphy, L.M.

    1985-09-16

    The energy conversion system includes a photo-voltaic array for receiving solar radiation and converting such radiation to electrical energy. The photo-voltaic array is mounted on a stretched membrane that is held by a frame. Tracking means for orienting the photo-voltaic array in predetermined positions that provide optimal exposure to solar radiation cooperate with the frame. An enclosure formed of a radiation transmissible material includes an inside containment space that accommodates the photo-voltaic array on the stretched membrane, the frame and the tracking means, and forms a protective shield for all such components. The enclosure is preferably formed of a flexible inflatable material and maintains its preferred form, such as a dome, under the influence of a low air pressure furnished to the dome. Under this arrangement the energy conversion system is streamlined for minimizing wind resistance, sufficiently weathproof for providing protection against weather hazards such as hail, capable of using diffused light, lightweight for low-cost construction and operational with a minimal power draw.

  16. Energy conversion system

    DOEpatents

    Murphy, Lawrence M.

    1987-01-01

    The energy conversion system includes a photo-voltaic array for receiving solar radiation and converting such radiation to electrical energy. The photo-voltaic array is mounted on a stretched membrane that is held by a frame. Tracking means for orienting the photo-voltaic array in predetermined positions that provide optimal exposure to solar radiation cooperate with the frame. An enclosure formed of a radiation transmissible material includes an inside containment space that accommodates the photo-voltaic array on the stretched membrane, the frame and the tracking means, and forms a protective shield for all such components. The enclosure is preferably formed of a flexible inflatable material and maintains its preferred form, such as a dome, under the influence of a low air pressure furnished to the dome. Under this arrangement the energy conversion system is streamlined for minimizing wind resistance, sufficiently weatherproof for providing protection against weather hazards such as hail, capable of using diffused light, lightweight for low-cost construction, and operational with a minimal power draw.

  17. Clean Fossil Energy Conversion Processes

    NASA Astrophysics Data System (ADS)

    Fan, L.-S.

    2007-03-01

    Absolute and per-capita energy consumption is bound to increase globally, leading to a projected increase in energy requirements of 50% by 2020. The primary source for providing a majority of the energy will continue to be fossil fuels. However, an array of enabling technologies needs to be proven for the realization of a zero emission power, fuel or chemical plants in the near future. Opportunities to develop new processes, driven by the regulatory requirements for the reduction or elimination of gaseous and particulate pollutant abound. This presentation describes the chemistry, reaction mechanisms, reactor design, system engineering, economics, and regulations that surround the utilization of clean coal energy. The presentation will cover the salient features of the fundamental and process aspects of the clean coal technologies in practice as well as in development. These technologies include those for the cleaning of SO2, H2S, NOx, and heavy metals, and separation of CO2 from the flue gas or the syngas. Further, new combustion and gasification processes based on the chemical looping concepts will be illustrated in the context of the looping particle design, process heat integration, energy conversion efficiency, and economics.

  18. Thermal Energy Conversion Branch

    NASA Technical Reports Server (NTRS)

    Bielozer, Matthew C.; Schreiber, Jeffrey, G.; Wilson, Scott D.

    2004-01-01

    The Thermal Energy Conversion Branch (5490) leads the way in designing, conducting, and implementing research for the newest thermal systems used in space applications at the NASA Glenn Research Center. Specifically some of the most advanced technologies developed in this branch can be broken down into four main areas: Dynamic Power Systems, Primary Solar Concentrators, Secondary Solar Concentrators, and Thermal Management. Work was performed in the Dynamic Power Systems area, specifically the Stirling Engine subdivision. Today, the main focus of the 5490 branch is free-piston Stirling cycle converters, Brayton cycle nuclear reactors, and heat rejection systems for long duration mission spacecraft. All space exploring devices need electricity to operate. In most space applications, heat energy from radioisotopes is converted to electrical power. The Radioisotope Thermoelectric Generator (RTG) already supplies electricity for missions such as the Cassini Spacecraft. The focus of today's Stirling research at GRC is aimed at creating an engine that can replace the RTG. The primary appeal of the Stirling engine is its high system efficiency. Because it is so efficient, the Stirling engine will significantly reduce the plutonium fuel mission requirements compared to the RTG. Stirling is also being considered for missions such as the lunar/Mars bases and rovers. This project has focused largely on Stirling Engines of all types, particularly the fluidyne liquid piston engine. The fluidyne was developed by Colin D. West. This engine uses the same concepts found in any type of Stirling engine, with the exception of missing mechanical components. All the working components are fluid. One goal was to develop and demonstrate a working Stirling Fluidyne Engine at the 2nd Annual International Energy Conversion Engineering Conference in Providence, Rhode Island.

  19. Solar energy conversion apparatus

    SciTech Connect

    Nash, S.G.

    1983-10-18

    Solar energy conversion apparatus is disclosed including a housing portion, an energy absorbing portion, a fluid directing portion and a cover portion; the housing portion including a molded plastic pan member including a base section with upwardly extending spaced spacer sections, the pan member including outwardly inclined sidewall sections having spaced inner and outer wall sections with a top section including an outwardly extending flange section and an inwardly extending slotted frame section; the energy absorbing portion including a conductive metal liner member positioned within the housing portion and resting on the upper surfaces of the spacer sections, a conductive metal separator section extending between the liner sidewall sections adjacent the upper ends thereof and enclosing the liner member; the fluid directing portion including a plurality of parallel spaced longitudinal baffle members arranged in a staggered relationship to provide a tortuous fluid path through the apparatus, an inlet opening and an outlet opening to the tortuous path, the baffle members extending upwardly from the liner bottom to the separator section; the cover portion including transparent impact resistant flat and dome members, the edges of the flat member being secured to the top section, the dome member being disposed over the flat member with its edges engaged with the flange section slots, the dome member including flat sections extending upwardly at an angle of 20/sup 0/ to 30/sup 0/ and a convex central section joining the flat sections.

  20. Energy conversion apparatus

    SciTech Connect

    Porter, D.R.

    1988-10-18

    This patent describes an energy conversion apparatus comprising: an engine, the engine comprising a cylinder and a piston reciprocally mounted therein, the cylinder defining a combustion chamber on one side of the piston for receiving a fuel mixture and a fluid drive chamber on the other side of the piston for receiving hydraulic fluid, a turbine, the turbine comprising a housing and a vaned turbine wheel rotatably mounted on a drive shaft journalled in the housing, hydraulic means for coupling fluid in the fluid drive chamber of the cylinder with the housing for rotatably driving the turbine wheel and the drive shaft upon a given movement of the piston, means for providing the combustion chamber of the engine with a fuel mixture comprising hydrogen and oxygen, an ignition means for selectively igniting the mixture in the combustion chamber, and purging means for selectively rotating the turbine prior to ignition of the fuel mixture in the engine to remove air therefrom, the purging means comprising a pump means for moving fluid from the reservoir into the fluid drive chambers, the conduit means and the turbine housing, whereby the piston driven by the ignited fuel mixture forces fluid in the fluid drive chamber against the vanes of the turbine wheel to rotate the drive shaft.

  1. Geothermal energy conversion facility

    SciTech Connect

    Kutscher, C.F.

    1997-12-31

    With the termination of favorable electricity generation pricing policies, the geothermal industry is exploring ways to improve the efficiency of existing plants and make them more cost-competitive with natural gas. The Geothermal Energy Conversion Facility (GECF) at NREL will allow researchers to study various means for increasing the thermodynamic efficiency of binary cycle geothermal plants. This work has received considerable support from the US geothermal industry and will be done in collaboration with industry members and utilities. The GECF is being constructed on NREL property at the top of South Table Mountain in Golden, Colorado. As shown in Figure 1, it consists of an electrically heated hot water loop that provides heating to a heater/vaporizer in which the working fluid vaporizes at supercritical or subcritical pressures as high as 700 psia. Both an air-cooled and water-cooled condenser will be available for condensing the working fluid. In order to minimize construction costs, available equipment from the similar INEL Heat Cycle Research Facility is being utilized.

  2. Energy conversion and storage program

    NASA Astrophysics Data System (ADS)

    1990-12-01

    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.

  3. Roadmap on optical energy conversion

    SciTech Connect

    Boriskina, Svetlana V.; Green, Martin A.; Catchpole, Kylie; Yablonovitch, Eli; Beard, Matthew C.; Okada, Yoshitaka; Lany, Stephan; Gershon, Talia; Zakutayev, Andriy; Tahersima, Mohammad H.; Sorger, Volker J.; Naughton, Michael J.; Kempa, Krzysztof; Dagenais, Mario; Yao, Yuan; Xu, Lu; Sheng, Xing; Bronstein, Noah D.; Rogers, John A.; Alivisatos, A. Paul; Nuzzo, Ralph G.; Gordon, Jeffrey M.; Wu, Di M.; Wisser, Michael D.; Salleo, Alberto; Dionne, Jennifer; Bermel, Peter; Greffet, Jean-Jacques; Celanovic, Ivan; Soljacic, Marin; Manor, Assaf; Rotschild, Carmel; Raman, Aaswath; Zhu, Linxiao; Fan, Shanhui; Chen, Gang

    2016-06-24

    For decades, progress in the field of optical (including solar) energy conversion was dominated by advances in the conventional concentrating optics and materials design. In recent years, however, conceptual and technological breakthroughs in the fields of nanophotonics and plasmonics combined with a better understanding of the thermodynamics of the photon energy-conversion processes reshaped the landscape of energy-conversion schemes and devices. Nanostructured devices and materials that make use of size quantization effects to manipulate photon density of states offer a way to overcome the conventional light absorption limits. Novel optical spectrum splitting and photon-recycling schemes reduce the entropy production in the optical energy-conversion platforms and boost their efficiencies. Optical design concepts are rapidly expanding into the infrared energy band, offering new approaches to harvest waste heat, to reduce the thermal emission losses, and to achieve noncontact radiative cooling of solar cells as well as of optical and electronic circuitries. Light-matter interaction enabled by nanophotonics and plasmonics underlie the performance of the third- and fourth-generation energy-conversion devices, including up- and down-conversion of photon energy, near-field radiative energy transfer, and hot electron generation and harvesting. Finally, the increased market penetration of alternative solar energy-conversion technologies amplifies the role of cost-driven and environmental considerations. This roadmap on optical energy conversion provides a snapshot of the state of the art in optical energy conversion, remaining challenges, and most promising approaches to address these challenges. Leading experts authored 19 focused short sections of the roadmap where they share their vision on a specific aspect of this burgeoning research field. The roadmap opens up with a tutorial section, which introduces major concepts and terminology. It is our hope that the roadmap

  4. Roadmap on optical energy conversion

    NASA Astrophysics Data System (ADS)

    Boriskina, Svetlana V.; Green, Martin A.; Catchpole, Kylie; Yablonovitch, Eli; Beard, Matthew C.; Okada, Yoshitaka; Lany, Stephan; Gershon, Talia; Zakutayev, Andriy; Tahersima, Mohammad H.; Sorger, Volker J.; Naughton, Michael J.; Kempa, Krzysztof; Dagenais, Mario; Yao, Yuan; Xu, Lu; Sheng, Xing; Bronstein, Noah D.; Rogers, John A.; Alivisatos, A. Paul; Nuzzo, Ralph G.; Gordon, Jeffrey M.; Wu, Di M.; Wisser, Michael D.; Salleo, Alberto; Dionne, Jennifer; Bermel, Peter; Greffet, Jean-Jacques; Celanovic, Ivan; Soljacic, Marin; Manor, Assaf; Rotschild, Carmel; Raman, Aaswath; Zhu, Linxiao; Fan, Shanhui; Chen, Gang

    2016-07-01

    For decades, progress in the field of optical (including solar) energy conversion was dominated by advances in the conventional concentrating optics and materials design. In recent years, however, conceptual and technological breakthroughs in the fields of nanophotonics and plasmonics combined with a better understanding of the thermodynamics of the photon energy-conversion processes reshaped the landscape of energy-conversion schemes and devices. Nanostructured devices and materials that make use of size quantization effects to manipulate photon density of states offer a way to overcome the conventional light absorption limits. Novel optical spectrum splitting and photon-recycling schemes reduce the entropy production in the optical energy-conversion platforms and boost their efficiencies. Optical design concepts are rapidly expanding into the infrared energy band, offering new approaches to harvest waste heat, to reduce the thermal emission losses, and to achieve noncontact radiative cooling of solar cells as well as of optical and electronic circuitries. Light-matter interaction enabled by nanophotonics and plasmonics underlie the performance of the third- and fourth-generation energy-conversion devices, including up- and down-conversion of photon energy, near-field radiative energy transfer, and hot electron generation and harvesting. Finally, the increased market penetration of alternative solar energy-conversion technologies amplifies the role of cost-driven and environmental considerations. This roadmap on optical energy conversion provides a snapshot of the state of the art in optical energy conversion, remaining challenges, and most promising approaches to address these challenges. Leading experts authored 19 focused short sections of the roadmap where they share their vision on a specific aspect of this burgeoning research field. The roadmap opens up with a tutorial section, which introduces major concepts and terminology. It is our hope that the roadmap

  5. Energy conversion at dipolarization fronts

    NASA Astrophysics Data System (ADS)

    Khotyaintsev, Yu. V.; Divin, A.; Vaivads, A.; André, M.; Markidis, S.

    2017-02-01

    We use multispacecraft observations by Cluster in the Earth's magnetotail and 3-D particle-in-cell simulations to investigate conversion of electromagnetic energy at the front of a fast plasma jet. We find that the major energy conversion is happening in the Earth (laboratory) frame, where the electromagnetic energy is being transferred from the electromagnetic field to particles. This process operates in a region with size of the order several ion inertial lengths across the jet front, and the primary contribution to E·j is coming from the motional electric field and the ion current. In the frame of the front we find fluctuating energy conversion with localized loads and generators at sub-ion scales which are primarily related to the lower hybrid drift instability excited at the front; however, these provide relatively small net energy conversion.

  6. Ocean Thermal Energy Conversion (OTEC)

    NASA Technical Reports Server (NTRS)

    Lavi, A.

    1977-01-01

    Energy Research and Development Administration research progress in Ocean Thermal Energy Conversion (OTEC) is outlined. The development program is being focused on cost effective heat exchangers; ammonia is generally used as the heat exchange fluid. Projected costs for energy production by OTEC vary between $1000 to $1700 per kW.

  7. Geothermal energy conversion system

    SciTech Connect

    Goldstein, D.

    1991-04-02

    This patent describes a combination with a source of heat energy, means for converting the heat energy into electrical energy. It comprises a pair of gears and frame means mounting the gears for rotation in operatively orientated relation to the source, one of the gears comprising a tubular element rotatably mounted by the frame means for exposure to the source of heat energy within a thermal heating region, the tubular element including deformable means in meshing engagement with the other of the gears within a thermally colder region for inducing rotation of the gears.

  8. Magnetohydrodynamics and Energy Conversion.

    DTIC Science & Technology

    CIRCUITS, CLOSTRIDIUM TETANI , COILS, ENERGY, FREQUENCY, HEAT TRANSFER, HYDROGEN, INDUCTANCE, LOW PRESSURE, MAGNETIC FIELDS, PINCH EFFECT, PHOTOMULTIPLIER TUBES, RODS, TEMPERATURE, THERMAL CONDUCTIVITY, THERMIONIC EMISSION.

  9. Laser energy conversion

    NASA Technical Reports Server (NTRS)

    Billman, K. W.

    1975-01-01

    Laser radiation could possibly provide a feasible approach for the transmission of energy between stations and vehicles in space and on earth. The transmitted energy could be used for the operational requirements of the receiving space station, lunar base, or spacecraft. In addition, laser energy could also be employed to provide power for the propulsion of vehicles in space. The present status of development regarding the various technological areas involved in an implementation of these objectives is examined, taking into account the possibility of further advances needed to satisfy the technical requirements. Attention is given to laser-induced chemistry for converting the radiation energy into chemical energy. Other subjects considered are related to photovoltaics, optical diodes, thermo-electronics, laser rockets, and photon engines.

  10. Solar energy conversion.

    SciTech Connect

    Crabtree, G. W.; Lewis, N. S.; Materials Science Division; Cal Tech

    2007-03-01

    The Sun provides Earth with a staggering amount of energy - enough to power the great oceanic and atmospheric currents, the cycle of evaporation and condensation that brings fresh water inland and drives river flow, and the typhoons, hurricanes, and tornadoes that so easily destroy the natural and built landscape. The San Francisco earthquake of 1906, with magnitude 7.8, released an estimated 10{sup 17} joules of energy, the amount the Sun delivers to Earth in one second. Earth's ultimate recoverable resource of oil, estimated at 3 trillion barrels, contains 1.7 x 10{sup 22} joules of energy, which the Sun supplies to Earth in 1.5 days. The amount of energy humans use annually, about 4.6 x 10{sup 20} joules, is delivered to Earth by the Sun in one hour. The enormous power that the Sun continuously delivers to Earth, 1.2 x 10{sup 5} terawatts, dwarfs every other energy source, renewable or nonrenewable. It dramatically exceeds the rate at which human civilization produces and uses energy, currently about 13 TW.

  11. Energy Conversion and Storage Program

    NASA Astrophysics Data System (ADS)

    Cairns, E. J.

    1993-06-01

    This report is the 1992 annual progress report for the Energy Conversion and Storage Program, a part of the Energy and Environment Division of the Lawrence Berkeley Laboratory. Work described falls into three broad areas: electrochemistry; chemical applications; and materials applications. The Energy Conversion and Storage Program applies principles of chemistry and materials science to solve problems in several areas: (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 chemical species, and (5) study and 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. 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 product and waste streams from synfuel plants, coal gasifiers, and biomass conversion processes. Materials applications research includes evaluation of the properties of advanced materials, as well as development of novel preparation techniques. For example, techniques such as sputtering, laser ablation, and poised laser deposition are being used to produce high-temperature superconducting films.

  12. Electrochemistry for Energy Conversion

    NASA Astrophysics Data System (ADS)

    O'Hayre, Ryan

    2010-10-01

    Imagine a laptop computer that runs for 30 hours on a single charge. Imagine a world where you plug your house into your car and power lines are a distant memory. These dreams motivate today's fuel cell research. While some dreams (like powering your home with your fuel cell car) may be distant, others (like a 30-hour fuel cell laptop) may be closer than you think. If you are curious about fuel cells---how they work, when you might start seeing them in your daily life--- this talk is for you. Learn about the state-of-the art in fuel cells, and where the technology is likely to be headed in the next 20 years. You'll also be treated to several ``behind-the scenes'' glimpses of cutting-edge research projects under development in the Renewable Energy Materials Center at the Colorado School of Mines--- projects like an ``ionic transistor'' that works with protons instead of electrons, and a special ceramic membrane material that enables the ``uphill'' diffusion of steam. Associate Professor Ryan O'Hayre's laboratory at the Colorado School of Mines develops new materials and devices to enable alternative energy technologies including fuel cells and solar cells. Prof. O'Hayre and his students collaborate with the Colorado Fuel Cell Center, the Colorado Center for Advanced Ceramics, the Renewable Energy Materials Science and Engineering Center, and the National Renewable Energy Laboratory.[4pt] In collaboration with Ann Deml, Jianhua Tong, Svitlana Pylypenko, Archana Subramaniyan, Micahael Sanders, Jason Fish, Annette Bunge, Colorado School of Mines.

  13. Energy conversion apparatus

    SciTech Connect

    Lawson, D. A.

    1984-10-09

    Apparatus for converting fluid energy into mechanical energy may include a sail and a mast carried by a pivotally mounted support. The sail is mounted both directly to the mast and indirectly to the mast through a boom, which is pivotally mounted at its center or along its length about the mast, and which is also mounted for tilting movement about a fastening extending perpendicularly to the mast. Positioning means periodically causes the boom to yaw about the mast and to tilt. Opposite edges of the sail thus alternately become taut leading edges with respect to incident wind or water and the sail adopts an oscillating motion which powers mechanical drive means such as pumps. The positioning means may be an over-center spring return or, in an alternative embodiment, be a hydraulic control mechanism. Advantages are that, because the sail remains full, it does not flap during repositioning even when formed of a light flexible material, which reduces inertial problems. Useful mechanical energy can be derived with a low level of technology from a large volume of incident fluid moving at a relatively low speed. The pressure from the pumps can be maintained at a constant value even if the speed of the incident fluid should alter.

  14. Multisource thermophotovoltaic energy conversion

    NASA Astrophysics Data System (ADS)

    Regan, Thomas M.; Martin, Jose G.; Riccobono, Juanita R.; Ludman, Jacques E.

    1995-09-01

    Recently, at the University of Massachusetts Lowell, promising Thermophotovoltaic (TPV) experimental results have been produced utilizing an experimental system that incorporates holographic optical elements and tubular geometry thermal sources. The results and concepts presented in this paper bring to light a unique merging of combustion and solar energy sources. The holographic elements provide a mechanism for spectral splitting, as well as concentration, while the tubular thermal source provides a flexible TPV photon emitter geometry that is capable of utilizing various thermal sources. The work reported here details the experiments as well as the concepts that indicate that such a TPV system could readily produce electricity utilizing 'dual' thermal sources. A tubular photon source was located in the focus of parabolic assembly to 'collimate' the photons emitted by a lamp simulating a TPV photon emitter. The collimated photons were directed onto the holographic element and spectrally redirected as a function of the photon energy. Components of a system constructed in this geometry can be readily converted to produce a highly concentrating solar photovoltaic electrical power source.

  15. Energy Conversion and Storage Program

    SciTech Connect

    Cairns, E.J.

    1992-03-01

    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.

  16. Advanced thermionic energy conversion

    NASA Technical Reports Server (NTRS)

    Britt, E. J.; Fitzpatrick, G. D.; Hansen, L. K.; Rasor, N. S.

    1974-01-01

    Basic analytical and experimental exploration was conducted on several types of advanced thermionic energy converters, and preliminary analysis was performed on systems utilizing advanced converter performance. The Pt--Nb cylindrical diode which exhibited a suppressed arc drop, as described in the preceding report, was reassembled and the existence of the postulated hydrid mode of operation was tentatively confirmed. Initial data obtained on ignited and unignited triode operation in the demountable cesium vapor system essentially confirmed the design principles developed in earlier work, with a few exceptions. Three specific advanced converter concepts were selected as candidates for concentrated basic study and for practical evaluation in fixed-configuration converters. Test vehicles and test stands for these converters and a unique controlled-atmosphere station for converter assembly and processing were designed, and procurement was initiated.

  17. Energy conversion in photosynthesis

    NASA Astrophysics Data System (ADS)

    Brudvig, Gary

    2011-03-01

    Photosystem II (PSII) uses light energy to split water into protons, electrons and O2. 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. Supported by NIH GM32715.

  18. Review of betavoltaic energy conversion

    NASA Technical Reports Server (NTRS)

    Olsen, Larry C.

    1993-01-01

    Betavoltaic energy conversion refers to the generation of power by coupling a beta source to a semiconductor junction device. The theory of betavoltaic energy conversion and some past studies of the subject are briefly reviewed. Calculations of limiting efficiencies for semiconductor cells versus bandgap are presented along with specific studies for Pm-147 and Ni-63 fueled devices. The approach used for fabricating Pm-147 fueled batteries by the author in the early 1970's is reviewed. Finally, the potential performance of advanced betavoltaic power sources is considered.

  19. Photochemical conversion of solar energy.

    PubMed

    Balzani, Vincenzo; Credi, Alberto; Venturi, Margherita

    2008-01-01

    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.

  20. Turbulence and energy conversion research

    SciTech Connect

    Hutchinson, R.A.

    1985-07-01

    This report examines the role of fluid mechanics research (particularly turbulence research) in improving energy conversion systems. In this report two of the listed application areas are selected as examples: fluidization and cavitation. Research needs in general, and research possibilities for ECUT in particular, are examined.

  1. Ocean thermal energy conversion (OTEC)

    SciTech Connect

    Lockerby, R.W.

    1981-01-01

    Ocean thermal energy conversion (OTEC) is reviewed briefly. The two types of OTEC system (open and closed) are described and limitations are pointed out. A bibliography of 148 references on OTEC is given for the time period 1975 to 1980. Entries are arranged alphabetically according to the author's name. (MJJ)

  2. Algal Energy Conversion and Capture

    NASA Astrophysics Data System (ADS)

    Hazendonk, P.

    2015-12-01

    We address the potential for energy conversions and capture for: energy generation; reduction in energy use; reduction in greenhouse gas emissions; remediation of water and air pollution; protection and enhancement of soil fertility. These processes have the potential to sequester carbon at scales that may have global impact. Energy conversion and capture strategies evaluate energy use and production from agriculture, urban areas and industries, and apply existing and emerging technologies to reduce and recapture energy embedded in waste products. The basis of biocrude production from Micro-algal feedstocks: 1) The nutrients from the liquid fraction of waste streams are concentrated and fed into photo bioreactors (essentially large vessels in which microalgae are grown) along with CO2 from flue gasses from down stream processes. 2) The algae are processed to remove high value products such as proteins and beta-carotenes. The advantage of algae feedstocks is the high biomass productivity is 30-50 times that of land based crops and the remaining biomass contains minimal components that are difficult to convert to biocrude. 3) The remaining biomass undergoes hydrothermal liquefaction to produces biocrude and biochar. The flue gasses of this process can be used to produce electricity (fuel cell) and subsequently fed back into the photobioreactor. The thermal energy required for this process is small, hence readily obtained from solar-thermal sources, and furthermore no drying or preprocessing is required keeping the energy overhead extremely small. 4) The biocrude can be upgraded and refined as conventional crude oil, creating a range of liquid fuels. In principle this process can be applied on the farm scale to the municipal scale. Overall, our primary food production is too dependent on fossil fuels. Energy conversion and capture can make food production sustainable.

  3. Experimental feasibility of the airborne measurement of absolute oil fluorescence spectral conversion efficiency

    NASA Technical Reports Server (NTRS)

    Hoge, F. E.; Swift, R. N.

    1983-01-01

    Airborne lidar oil spill experiments carried out to determine the practicability of the AOFSCE (absolute oil fluorescence spectral conversion efficiency) computational model are described. The results reveal that the model is suitable over a considerable range of oil film thicknesses provided the fluorescence efficiency of the oil does not approach the minimum detection sensitivity limitations of the lidar system. Separate airborne lidar experiments to demonstrate measurement of the water column Raman conversion efficiency are also conducted to ascertain the ultimate feasibility of converting such relative oil fluorescence to absolute values. Whereas the AOFSCE model is seen as highly promising, further airborne water column Raman conversion efficiency experiments with improved temporal or depth-resolved waveform calibration and software deconvolution techniques are thought necessary for a final determination of suitability.

  4. Observation of Thermoacoustic Energy Conversion

    NASA Astrophysics Data System (ADS)

    Tashiro, Yusuke; Biwa, Tetsushi; Yazaki, Taichi

    In order to understand thermoacoustic phenomena from a point of view of thermodynamics, oscillating pressure, velocity and temperature were measured in the tube having a temperature gradient. By converting the measured Eulerian quantities to the Lagrangian quantities associated with a given gas parcel, we determined the local energy conversion rate per unit volume and time. The obtained data demonstrate the validity of the thermodynamic approach to thermoacoustic phenomena.

  5. Direct Energy Conversion Literature Abstracts

    DTIC Science & Technology

    1963-12-01

    for single and multiloop first in handy packages for use anywhere Carnot cycles. Parameters related to on earth or in space, and eventually in...by Various inorganic fluids which may be o F.X. Dobler, and others.306p., Feb.8,1962. potential value for energy conversion or (Prog. Rept.- First Q...during the first three months. background material is discussed, including thermodynamic cycle, heat transfer, compati- 4679 bility, and working

  6. Direct Energy Conversion Literature Abstracts

    DTIC Science & Technology

    1962-12-01

    3530-3533 4. Fusion ........................................................ 3534-3536 C. Solar Collection and Concentration...Cooley, W.C. SOLAR DIRECT-CONVERSION. 245p., New York, United Nations, 1961. POWER SYSTEMS. Inst. Radio Engra. Trans. MIL-6: 91-98, illus., Jan. j 1962...In ch.V entitled Fuel and Power Research, nuclear and solar energy are discussed, in A survey is made of the present status of general. technology of

  7. Materials for thermoelectric energy conversion

    NASA Technical Reports Server (NTRS)

    Wood, C.

    1988-01-01

    The field of thermoelectric energy conversion is reviewed from both a theoretical and an experimental standpoint. The basic theory is introduced and the thermodynamic and solid state views are compared. An overview of the development of thermoelectric materials is presented with particular emphasis being placed on the most recent developments in high-temperature semiconductors. A number of possible device applications are discussed and the successful use and suitability of these devices for space power is manifest.

  8. Radiation energy conversion in space

    NASA Technical Reports Server (NTRS)

    Billman, K. W.

    1979-01-01

    Topics discussed at the third NASA conference on radiant energy conversion are reviewed. The unconcentrated-photovoltaic-generation version of a solar power satellite is described, noting that it will consist of a 21.3 x 5.3-sq-km silicon-solar-cell array expected to provide 17 Gw of electrical power, with 1 km in diam transmitters oriented to beam 2.45 GHz microwave power to two receiving/rectifying 'rectennas' on earth. The Solares space-energy-system concept, designed for providing a large fraction of the world's energy needs at costs comparable to those of future coal/nuclear alternative, is considered, as are subsystems for improving the economics of the solar power satellite. A concept proposing the use of relativistic-electron-storage rings for electron-beam energy transmission and storage, and a report on the production of a high temperature plasma with concentrated solar radiation are taken into account. Laser-conversion systems, including the direct-solar-pumped space laser, and the telec-powered spacecraft, are discussed.

  9. Fundamentals of solar energy conversion

    NASA Astrophysics Data System (ADS)

    Anderson, E. E.

    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.

  10. Ocean thermal-energy conversion

    NASA Astrophysics Data System (ADS)

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

    1983-03-01

    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.

  11. Biological Solar Energy Conversion and U.S. Energy Policy

    ERIC Educational Resources Information Center

    Pimentel, David; And Others

    1978-01-01

    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)

  12. Biomass conversion processes for energy and fuels

    NASA Astrophysics Data System (ADS)

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

    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.

  13. Thermophotovoltaic Energy Conversion Development Program

    NASA Technical Reports Server (NTRS)

    Shukla, Kailash; Doyle, Edward; Becker, Frederick

    1998-01-01

    Completely integrated thermophotovoltaic (TPV) power sources in the range of 100 to 500 watts are being developed. The technical approach taken in this project focuses on optimizing the integrated performance of the primary subsystems in order to yield high energy conversion efficiency and cost effectiveness. An important aspect of the approach is the use of a narrow band fibrous emitter radiating to a bandgap matched photovoltaic array to minimize thermal and optical recuperation requirements, as well as the non-recoverable heat losses. For the prototype system, fibrous ytterbia emitters radiating in a narrow band centered at 980 nm are matched with high efficiency silicon photoconverters. The integrated system includes a dielectric stack filter for optical energy recovery and a ceramic recuperator for thermal energy recovery. The prototype TPV system uses a rapid mix distributed fuel delivery system with controlled feeding of the fuel and heated air into a flame at the surface of the emitter. This makes it possible to operate at air preheat temperatures well above the auto-ignition temperature of the fuel thereby substantially increasing the system efficiency. The system has been operated with air preheat temperatures up to 1367 K and has produced a uniform narrow band radiation over the surface of the emitter with this approach. The design of the system is described and test data for the system and some of the key components are presented. The results from a system model, which show the impact of various parameters on system performance, are also discussed.

  14. Thermodynamics fundamentals of energy conversion

    NASA Astrophysics Data System (ADS)

    Dan, Nicolae

    The work reported in the chapters 1-5 focuses on the fundamentals of heat transfer, fluid dynamics, thermodynamics and electrical phenomena related to the conversion of one form of energy to another. Chapter 6 is a re-examination of the fundamental heat transfer problem of how to connect a finite-size heat generating volume to a concentrated sink. Chapter 1 extends to electrical machines the combined thermodynamics and heat transfer optimization approach that has been developed for heat engines. The conversion efficiency at maximum power is 1/2. When, as in specific applications, the operating temperature of windings must not exceed a specified level, the power output is lower and efficiency higher. Chapter 2 addresses the fundamental problem of determining the optimal history (regime of operation) of a battery so that the work output is maximum. Chapters 3 and 4 report the energy conversion aspects of an expanding mixture of hot particles, steam and liquid water. At the elemental level, steam annuli develop around the spherical drops as time increases. At the mixture level, the density decreases while the pressure and velocity increases. Chapter 4 describes numerically, based on the finite element method, the time evolution of the expanding mixture of hot spherical particles, steam and water. The fluid particles are moved in time in a Lagrangian manner to simulate the change of the domain configuration. Chapter 5 describes the process of thermal interaction between the molten material and water. In the second part of the chapter the model accounts for the irreversibility due to the flow of the mixture through the cracks of the mixing vessel. The approach presented in this chapter is based on exergy analysis and represents a departure from the line of inquiry that was followed in chapters 3-4. Chapter 6 shows that the geometry of the heat flow path between a volume and one point can be optimized in two fundamentally different ways. In the "growth" method the

  15. The chemistry of energy conversion and storage.

    PubMed

    Su, Dang Sheng

    2014-05-01

    What's in store: The sustainable development of our society requires the conversion and storage of renewable energy, and these should be scaled up to serve the global primary energy consumption. This special issue on "The Chemistry of Energy Conversion and Storage", assembled by guest editor Dangsheng Su, contains papers dealing with these aspects, and highlights important developments in the chemistry of energy conversion and storage during the last two years.

  16. Tropospheric effects of energy conversion

    SciTech Connect

    Derwent, R.G. )

    1992-01-01

    The tropospheric concentrations of a number of trace gases are increasing due to man's activities. For some trace gases, their atmospheric life cycles are not fully understood and it is difficult to be certain about the role of man's activities. Emissions from the energy industries and energy conversion processes represent an important subset of source terms in these life cycles, along with agriculture, deforestation, cement manufacture, biomass burning, process industries and natural biospheric processes. Global Warming Potentials (GWPs) allow the tropospheric effects of a range of climate forcing trace gases to be assessed on a comparable basis. If a short term view of the commitment to global warming is adopted then the contribution from other trace gases may approach and exceed that of carbon dioxide, itself. Over longer time horizons, the long atmospheric lifetime of carbon dioxide shows through as a major influence and the contributions from the other trace gases appear to be much smaller, representing an additional 13-18[percent] contribution on top of that from CO[sub 2] itself.

  17. Solar energy, its conversion and utilization

    NASA Technical Reports Server (NTRS)

    Farber, E. A.

    1972-01-01

    The work being carried out at the University of Florida Solar Energy and Energy Conversion Laboratory in converting solar energy, our only income, into other needed and useful forms of energy is described. A treatment such as this demonstrates, in proper perspective, how solar energy can benefit mankind with its many problems of shortages and pollution. Descriptions were given of the conversion processes, equipment, and performance. The testing of materials, solar water heating, space heating, cooking and baking, solar distillation, refrigeration and air-conditioning, work with the solar furnace, conversion to mechanical power, hot air engines, solar-heated sewage digestion, conversion to electricity, and other devices will be discussed.

  18. Energy Conversion Alternatives Study (ECAS)

    NASA Technical Reports Server (NTRS)

    1977-01-01

    ECAS compared various advanced energy conversion systems that can use coal or coal-derived fuels for baseload electric power generation. It was conducted in two phases. Phase 1 consisted of parametric studies. From these results, 11 concepts were selected for further study in Phase 2. For each of the Phase 2 systems and a common set of ground rules, performance, cost, environmental intrusion, and natural resource requirements were estimated. In addition, the contractors defined the state of the associated technology, identified the advances required, prepared preliminary research and development plans, and assessed other factors that would affect the implementation of each type of powerplant. The systems studied in Phase 2 include steam systems with atmospheric- and pressurized-fluidized-bed boilers; combined cycle gas turbine/steam systems with integrated gasifiers or fired by a semiclean, coal derived fuel; a potassium/steam system with a pressurized-fluidized-bed boiler; a closed-cycle gas turbine/organic system with a high-temperature, atmospheric-fluidized-bed furnace; a direct-coal-fired, open- cycle magnetohydrodynamic/steam system; and a molten-carbonate fuel cell/steam system with an integrated gasifier. The sensitivity of the results to changes in the ground rules and the impact of uncertainties in capital cost estimates were also examined.

  19. Terrestrial solar thermionic energy conversion systems concept

    NASA Technical Reports Server (NTRS)

    Shimada, K.; Swerdling, M.

    1975-01-01

    Results obtained from studies of a (1) solar concentrator, (2) solar energy receiver - thermionic converter system, and (3) solar thermionic topping system are described. Peripheral subsystems, which are required for any solar energy conversion system, are also discussed.

  20. The absolute energy flux envelopes of B type stars.

    NASA Technical Reports Server (NTRS)

    Underhill, A. B.

    1972-01-01

    Absolute energy flux envelopes covering the region of 1100 to 6000 A for main-sequence stars of types B3, B7 and A0 derived from published, ground-based observations and from spectrum scans with OAO-II are presented. These flux envelopes are compared with the predicted flux envelopes from lightly line-blanketed model atmospheres. The line blanketing at wavelengths shorter than 3000 A is severe, about one-half the predicted light being observed at 1600 A. These results demonstrate that a model which represents well the observed visible spectrum of a star may fail seriously for representing the ultraviolet spectrum.

  1. NASA presentation. [wind energy conversion systems planning

    NASA Technical Reports Server (NTRS)

    Thomas, R. L.

    1973-01-01

    The development of a wind energy system is outlined that supplies reliable energy at a cost competitive with other energy systems. A government directed industry program with strong university support is recommended that includes meteorological studies to estimate wind energy potentials and determines favorable regions and sites for wind power installations. Key phases of the overall program are wind energy conversion systems, meteorological wind studies, energy storage systems, and environmental impact studies. Performance testing with a prototype wind energy conversion and storage system is projected for Fiscal 1977.

  2. Electrochemical considerations for determining absolute frontier orbital energy levels of conjugated polymers for solar cell applications.

    PubMed

    Cardona, Claudia M; Li, Wei; Kaifer, Angel E; Stockdale, David; Bazan, Guillermo C

    2011-05-24

    Narrow bandgap conjugated polymers in combination with fullerene acceptors are under intense investigation in the field of organic photovoltaics (OPVs). The open circuit voltage, and thereby the power conversion efficiency, of the devices is related to the offset of the frontier orbital energy levels of the donor and acceptor components, which are widely determined by cyclic voltammetry. Inconsistencies have appeared in the use of the ferrocenium/ferrocene (Fc + /Fc) redox couple, as well as the values used for the absolute potentials of standard electrodes, which can complicate the comparison of materials properties and determination of structure/property relationships.

  3. Energy Conversion in Natural and Artificial Photosynthesis

    PubMed Central

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

    2010-01-01

    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. PMID:20534342

  4. NSF presentation. [summary on energy conversion research program

    NASA Technical Reports Server (NTRS)

    Morse, F. H.

    1973-01-01

    Wind energy conversion research is considered in the framework of the national energy problem. Research and development efforts for the practical application of solar energy -- including wind energy -- as alternative energy supplies are assessed in: (1) Heating and cooling of buildings; (2) photovoltaic energy conversion; (3) solar thermal energy conversion; (4) wind energy conversion; (5) ocean thermal energy conversion; (6) photosynthetic production of organic matter; and (7) conversion of organic matter into fuels.

  5. Energy conversion & storage program. 1994 annual report

    SciTech Connect

    Cairns, E.J.

    1995-04-01

    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.

  6. Energy Conversion & Storage Program, 1993 annual report

    SciTech Connect

    Cairns, E.J.

    1994-06-01

    The Energy Conversion and Storage Program applies chemistry and materials science principles to solve problems in: production of new synthetic fuels; development of high-performance rechargeable batteries and fuel cells; development of high-efficiency thermochemical processes for energy conversion; characterization of complex chemical processes and chemical species; and the study and application of novel materials for energy conversion and transmission. Projects focus on transport-process principles, chemical kinetics, thermodynamics, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials, and advanced methods of analysis.

  7. Figures of Merit for Energy Conversion Processes

    ERIC Educational Resources Information Center

    Rubin, Morton H.

    1978-01-01

    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)

  8. Second NASA Conference on Laser Energy Conversion

    NASA Technical Reports Server (NTRS)

    Billman, K. W. (Editor)

    1976-01-01

    The possible transmission of high power laser beams over long distances and their conversion to thrust, electricity, or other useful forms of energy is considered. Specific topics discussed include: laser induced chemistry; developments in photovoltaics, including modification of the Schottky barrier devices and generation of high voltage emf'sby laser radiation of piezoelectric ceramics; the thermo electronic laser energy converter and the laser plasmadynamics converters; harmonic conversion of infrared laser radiation in molecular gases; and photon engines.

  9. Electromagnetic wave energy conversion research

    NASA Technical Reports Server (NTRS)

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

    1975-01-01

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

  10. Electromagnetic energy conversion at reconnection fronts.

    PubMed

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

    2013-09-27

    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.

  11. Thermionic Energy Conversion (TEC) topping thermoelectrics

    NASA Technical Reports Server (NTRS)

    Morris, J. F.

    1981-01-01

    Performance expectations for thermionic and thermoelectric energy conversion systems are reviewed. It is noted that internal radiation effects diminish thermoelectric figures of merit significantly at 1000 K and substantially at 2000 K; the effective thermal conductivity contribution of intrathermoelectric radiative dissipation increases with the third power of temperature. It is argued that a consideration of thermoelectric power generation with high temperature heat sources should include utilization of thermionic energy conversion (TEC) topping thermoelectrics. However TEC alone or TEC topping more efficient conversion systems like steam or gas turbines, combined cycles, or Stirling engines would be more desirable generally.

  12. Thermionic energy conversion technology - Present and future

    NASA Technical Reports Server (NTRS)

    Shimada, K.; Morris, J. F.

    1977-01-01

    Aerospace and terrestrial applications of thermionic direct energy conversion and advances in direct energy conversion (DEC) technology are surveyed. Electrode materials, the cesium plasma drop (the difference between the barrier index and the collector work function), DEC voltage/current characteristics, conversion efficiency, and operating temperatures are discussed. Attention is centered on nuclear reactor system thermionic DEC devices, for in-core or out-of-core operation. Thermionic fuel elements, the radiation shield, power conditions, and a waste heat rejection system are considered among the thermionic DEC system components. Terrestrial applications include topping power systems in fossil fuel and solar power generation.

  13. Photoelectrochemical cells - Conversion of intense optical energy

    NASA Technical Reports Server (NTRS)

    Wrighton, M. S.; Ellis, A. B.; Kaiser, S. W.

    1976-01-01

    Conversion of optical energy to chemical energy and/or electrical energy using wet photoelectrochemical cells is described. Emphasis is on (1) the photoelectrolysis of H2O to H2 and O2 using cells having n-type semiconductor photoelectrodes fabricated from TiO2, SnO2, SrTiO3, KTaO3, and KTa(0.77)Nb(0.23)O3, and (2) the conversion of light to electrical energy using CdSe- and CdS-based cells with polysulfide electrolytes.

  14. Theoretical investigation of vacuum thermionic energy conversion devices for efficient conversion of solar to electrical energy

    NASA Astrophysics Data System (ADS)

    Smith, Joshua; Nemanich, Robert; Bilbro, Griff

    2007-03-01

    A vacuum thermionic energy conversion device (TEC) would offer the potential of efficiently converting solar energy directly to electrical work. These devices consist of a heated emitter electrode and a collector electrode separated by an evacuated interelectrode space. Models for such conceptual devices are developed, and efficiency is calculated by considering electron transport across the device as well as Stefan Boltzmann radiation. A device operating with an emitter and collector temperature of 775K and 375K, respectively is considered. The conceptual TEC features diamond materials having low emission barrier heights as electrodes. Hydrogen terminated diamond is known to have a negative electron affinity (NEA) and nitrogen or phosphorus doping introduces donor levels at 1.7eV and 0.6eV, respectively, below the conduction band minimum. For the devices considered, the barrier heights are 1.1eV and 0.5eV for the emitter and collector, respectively. The Richardson constant is 10A/cm^2K^2, consistant with experimental results. Assuming an emissivity of 0.5, the device has a Carnot efficiency of 0.52, and a calculated absolute efficiency of 0.17 at a maximum power of 0.25W/cm^2. The theory is extended to include the negative space charge effect, and the NEA properties of the materials are shown to mitigate the space charge effect and increase output power.

  15. Absolute calorimetric calibration of low energy brachytherapy sources

    NASA Astrophysics Data System (ADS)

    Stump, Kurt E.

    In the past decade there has been a dramatic increase in the use of permanent radioactive source implants in the treatment of prostate cancer. A small radioactive source encapsulated in a titanium shell is used in this type of treatment. The radioisotopes used are generally 125I or 103Pd. Both of these isotopes have relatively short half-lives, 59.4 days and 16.99 days, respectively, and have low-energy emissions and a low dose rate. These factors make these sources well suited for this application, but the calibration of these sources poses significant metrological challenges. The current standard calibration technique involves the measurement of ionization in air to determine the source air-kerma strength. While this has proved to be an improvement over previous techniques, the method has been shown to be metrologically impure and may not be the ideal means of calbrating these sources. Calorimetric methods have long been viewed to be the most fundamental means of determining source strength for a radiation source. This is because calorimetry provides a direct measurement of source energy. However, due to the low energy and low power of the sources described above, current calorimetric methods are inadequate. This thesis presents work oriented toward developing novel methods to provide direct and absolute measurements of source power for low-energy low dose rate brachytherapy sources. The method is the first use of an actively temperature-controlled radiation absorber using the electrical substitution method to determine total contained source power of these sources. The instrument described operates at cryogenic temperatures. The method employed provides a direct measurement of source power. The work presented here is focused upon building a metrological foundation upon which to establish power-based calibrations of clinical-strength sources. To that end instrument performance has been assessed for these source strengths. The intent is to establish the limits of

  16. Synchronous generator wind energy conversion control system

    SciTech Connect

    Medeiros, A.L.R.; Lima, A.M.N.; Jacobina, C.B.; Simoes, F.J.

    1996-12-31

    This paper presents the performance evaluation and the design of the control system of a WECS (Wind Energy Conversion System) that employs a synchronous generator based on its digital simulation. The WECS discussed in this paper is connected to the utility grid through two Pulse Width Modulated (PWM) power converters. The structure of the proposed WECS enables us to achieve high performance energy conversion by: (i) maximizing the wind energy capture and (ii) minimizing the reactive power flowing between the grid and the synchronous generator. 8 refs., 19 figs.

  17. Energy Conversion: Nano Solar Cell

    NASA Astrophysics Data System (ADS)

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

    2009-09-01

    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 c//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.

  18. SPS Energy Conversion Power Management Workshop

    NASA Technical Reports Server (NTRS)

    1980-01-01

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

  19. High-Temperature Thermoelectric Energy Conversion

    NASA Technical Reports Server (NTRS)

    Wood, C.

    1987-01-01

    Theory of thermoelectric energy conversion at high temperatures and status of research on conversion materials reviewed in report. Shows highest values of thermoelectric figure of merit, Z, found in semiconductor materials. Semiconductors keep wide choice of elements and compounds. Electrical properties tailored to particular application by impurity doping and control of stoichiometry. Report develops definition of Z useful for comparing materials and uses it to evaluate potentials of different classes of materialsmetals, semiconductors, and insulators.

  20. US energy conversion and use characteristics

    SciTech Connect

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

    1982-02-01

    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)

  1. Predictions of Ligand Selectivity from Absolute Binding Free Energy Calculations

    PubMed Central

    2016-01-01

    Binding selectivity is a requirement for the development of a safe drug, and it is a critical property for chemical probes used in preclinical target validation. Engineering selectivity adds considerable complexity to the rational design of new drugs, as it involves the optimization of multiple binding affinities. Computationally, the prediction of binding selectivity is a challenge, and generally applicable methodologies are still not available to the computational and medicinal chemistry communities. Absolute binding free energy calculations based on alchemical pathways provide a rigorous framework for affinity predictions and could thus offer a general approach to the problem. We evaluated the performance of free energy calculations based on molecular dynamics for the prediction of selectivity by estimating the affinity profile of three bromodomain inhibitors across multiple bromodomain families, and by comparing the results to isothermal titration calorimetry data. Two case studies were considered. In the first one, the affinities of two similar ligands for seven bromodomains were calculated and returned excellent agreement with experiment (mean unsigned error of 0.81 kcal/mol and Pearson correlation of 0.75). In this test case, we also show how the preferred binding orientation of a ligand for different proteins can be estimated via free energy calculations. In the second case, the affinities of a broad-spectrum inhibitor for 22 bromodomains were calculated and returned a more modest accuracy (mean unsigned error of 1.76 kcal/mol and Pearson correlation of 0.48); however, the reparametrization of a sulfonamide moiety improved the agreement with experiment. PMID:28009512

  2. Energy from Biomass for Conversion of Biomass

    NASA Astrophysics Data System (ADS)

    Abolins, J.; Gravitis, J.

    2009-01-01

    Along with estimates of minimum energy required by steam explosion pre-treatment of biomass some general problems concerning biomass conversion into chemicals, materials, and fuels are discussed. The energy necessary for processing biomass by steam explosion auto-hydrolysis is compared with the heat content of wood and calculated in terms of the amount of saturated steam consumed per unit mass of the dry content of wood biomass. The fraction of processed biomass available for conversion after steam explosion pre-treatment is presented as function of the amount of steam consumed per unit mass of the dry content of wood. The estimates based on a simple model of energy flows show the energy required by steam explosion pre-treatment of biomass being within 10% of the heat content of biomass - a realistic amount demonstrating that energy for the process can be supplied from a reasonable proportion of biomass used as the source of energy for steam explosion pre-treatment.

  3. A new wind energy conversion system

    NASA Technical Reports Server (NTRS)

    Smetana, F. O.

    1975-01-01

    It is presupposed that vertical axis wind energy machines will be superior to horizontal axis machines on a power output/cost basis and the design of a new wind energy machine is presented. The design employs conical cones with sharp lips and smooth surfaces to promote maximum drag and minimize skin friction. The cones are mounted on a vertical axis in such a way as to assist torque development. Storing wind energy as compressed air is thought to be optimal and reasons are: (1) the efficiency of compression is fairly high compared to the conversion of mechanical energy to electrical energy in storage batteries; (2) the release of stored energy through an air motor has high efficiency; and (3) design, construction, and maintenance of an all-mechanical system is usually simpler than for a mechanical to electrical conversion system.

  4. Energy conversion & storage program. 1995 annual report

    SciTech Connect

    Cairns, E.J.

    1996-06-01

    The 1995 annual report discusses laboratory activities in the Energy Conversion and Storage (EC&S) Program. The report is divided into three categories: electrochemistry, chemical applications, and material applications. Research performed in each category during 1995 is described. Specific research topics relate to the development of high-performance rechargeable batteries and fuel cells, the development of high-efficiency thermochemical processes for energy conversion, the characterization of new chemical processes and complex chemical species, and the study and application of novel materials related to energy conversion and transmission. Research projects focus on transport-process principles, chemical kinetics, thermodynamics, separation processes, organic and physical chemistry, novel materials and deposition technologies, and advanced methods of analysis.

  5. Surface Plasmon-Assisted Solar Energy Conversion.

    PubMed

    Dodekatos, Georgios; Schünemann, Stefan; Tüysüz, Harun

    2016-01-01

    The utilization of localized surface plasmon resonance (LSPR) from plasmonic noble metals in combination with semiconductors promises great improvements for visible light-driven photocatalysis, in particular for energy conversion. This review summarizes the basic principles of plasmonic photocatalysis, giving a comprehensive overview about the proposed mechanisms for enhancing the performance of photocatalytically active semiconductors with plasmonic devices and their applications for surface plasmon-assisted solar energy conversion. The main focus is on gold and, to a lesser extent, silver nanoparticles in combination with titania as semiconductor and their usage as active plasmonic photocatalysts. Recent advances in water splitting, hydrogen generation with sacrificial organic compounds, and CO2 reduction to hydrocarbons for solar fuel production are highlighted. Finally, further improvements for plasmonic photocatalysts, regarding performance, stability, and economic feasibility, are discussed for surface plasmon-assisted solar energy conversion.

  6. Harnessing surface plasmons for solar energy conversion

    NASA Technical Reports Server (NTRS)

    Anderson, L. M.

    1983-01-01

    NASA research on the feasibility of solar-energy conversion using surface plasmons is reviewed, with a focus on inelastic-tunnel-diode techniques for power extraction. The need for more efficient solar converters for planned space missions is indicated, and it is shown that a device with 50-percent efficiency could cost up to 40 times as much per sq cm as current Si cells and still be competitive. The parallel-processing approach using broadband carriers and tunable diodes is explained, and the physics of surface plasmons on metal surfaces is outlined. Technical problems being addressed include phase-matching sunlight to surface plasmons, minimizing ohmic losses and reradiation in energy transport, coupling into the tunnels by mode conversion, and gaining an understanding of the tunnel-diode energy-conversion process. Diagrams illustrating the design concepts are provided.

  7. On the calculation of absolute macromolecular binding free energies

    PubMed Central

    Luo, Hengbin; Sharp, Kim

    2002-01-01

    The standard framework for calculating the absolute binding free energy of a macromolecular association reaction A + B → AB with an association constant KAB is to equate chemical potentials of the species on the left- and right-hand sides of this reaction and evaluate the chemical potentials from theory. This theory involves (usually hidden) assumptions about what constitutes the bound species, AB, and where the contribution of the solvent appears. We present here an alternative derivation that can be traced back to Bjerrum, in which the expectation value of KAB is obtained directly through the statistical mechanical method of evaluating its ensemble (Boltzmann-weighted) average. The generalized Bjerrum approach more clearly delineates: (i) the different contributions to binding; (ii) the origin of the much-discussed and somewhat controversial association entropy term; and (iii) where the solvent contribution appears. This approach also allows approximations required for practical evaluation of the binding constant in complex macromolecular systems, to be introduced in a well defined way. We provide an example, with application to test cases that illustrate a range of binding behavior. PMID:12149474

  8. Silicon nanowires for photovoltaic solar energy conversion.

    PubMed

    Peng, Kui-Qing; Lee, Shuit-Tong

    2011-01-11

    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.

  9. Fullerene assemblies toward photo-energy conversions.

    PubMed

    Shen, Yanfei; Nakanishi, Takashi

    2014-04-28

    Manipulating molecular interaction and assembly for developing various functional nanostructures with controlled dimensionality, morphology and tailored properties is currently a research focus in molecular science and materials chemistry. Particularly, the self-organization of fullerenes (i.e. C60) to form various functional assemblies has received intense interest since it can provide excellent optoelectronic properties for photo-energy conversion-induced applications such as solar cells and field effect transistors (FET). In this perspective, we describe our recent efforts toward the development in the area of fullerene molecular design and assemblies aimed at improving the photoconductivity and photo-energy (electric and thermal) conversion systems.

  10. Conversion of laser energy to gas kinetic energy

    NASA Technical Reports Server (NTRS)

    Caledonia, G. E.

    1976-01-01

    Techniques for the gas phase absorption of laser radiation for ultimate conversion to gas kinetic energy are discussed. Particular emphasis is placed on absorption by the vibration rotation bands of diatomic molecules at high pressures. This high pressure absorption appears to offer efficient conversion of laser energy to gas translational energy. Bleaching and chemical effects are minimized and the variation of the total absorption coefficient with temperature is minimal.

  11. Energy conversion in laser propulsion: III

    NASA Astrophysics Data System (ADS)

    Larson, Carl W.; Mead, Franklin B., Jr.; Kalliomaa, Wayne M.

    2002-09-01

    Conversion of pulses of CO2 laser energy (18 microsecond pulses) to propellant kinetic energy was studied in a Myrabo Laser Lightcraft (MLL) operating with laser heated STP air and laser ablated delrin propellants. The MLL incorporates an inverted parabolic reflector that focuses laser energy into a toroidal volume where it is absorbed by a unit of propellant mass that subsequently expands in the geometry of the plug nozzle aerospike. With Delrin propellant, measurements of the coupling coefficients and the ablated mass as a function of laser pulse energy showed that the efficiency of conversion of laser energy to propellant kinetic energy was approximately 54%. With STP air, direct experimental measurement efficiency was not possible because the propellant mass associated with measured coupling coefficients was not known. Thermodynamics predicted that the upper limit of the efficiency of conversion of the internal energy of laser heated air to jet kinetic energy, (alpha) , is approximately 0.30 for EQUILIBRIUM expansion to 1 bar pressure. For FROZEN expansion (alpha) approximately 0.27. These upper limit efficiencies are nearly independent of the initial specific energy from 1 to 110 MJ/kg. With heating of air at its Mach 5 stagnation density (5.9 kg/m3 as compared to STP air density of 1.18 kg/m3) these efficiencies increase to about 0.55 (equilibrium) and 0.45 (frozen). Optimum blowdown from 1.18 kg/m3 to 1 bar occurs with expansion ratios approximately 1.5 to 4 as internal energy increases from 1 to 100 MJ/kg. Optimum expansion from the higher density state requires larger expansion ratios, 8 to 32. Expansion of laser ablated Delrin propellant appears to convert the absorbed laser energy more efficiently to jet kinetic energy because the effective density of the ablated gaseous Delrin is significantly greater than that of STP air.

  12. Energy conversion in laser propulsion III

    NASA Astrophysics Data System (ADS)

    Larson, C. William; Mead, Franklin B.; Kalliomaa, Wayne M.

    2003-05-01

    Conversion of pulses of CO2 laser energy (18 microsecond pulses) to propellant kinetic energy was studied in a Myrabo Laser Lightcraft (MLL) operating with laser heated STP air and laser ablated delrin propellants. The MLL incorporates an inverted parabolic reflector that focuses laser energy into a toroidal volume where it is absorbed by a unit of propellant mass that subsequently expands in the geometry of the plug nozzle aerospike. With Delrin propellant, measurements of the coupling coefficients and the ablated mass as a function of laser pulse energy showed that the efficiency of conversion of laser energy to propellant kinetic energy was ~ 54%. With STP air, direct experimental measurement of efficiency was not possible because the propellant mass associated with measured coupling coefficients was not known. Thermodynamics predicted that the upper limit of the efficiency of conversion of the internal energy of laser heated air to jet kinetic energy, α, is ~ 0.30 for EQUILIBRIUM expansion to 1 bar pressure. For FROZEN expansion α ~ 0.27. These upper limit efficiencies are nearly independent of the initial specific energy from 1 to 110 MJ/kg. With heating of air at its Mach 5 stagnation density (5.9 kg/m3 as compared to STP air density of 1.18 kg/m3) these efficiencies increase to about 0.55 (equilibrium) and 0.45 (frozen). Optimum blowdown from 1.18 kg/m3 to 1 bar occurs with expansion ratios ~ 1.5 to 4 as internal energy increases from 1 to 100 MJ/kg. Optimum expansion from the higher density state requires larger expansion ratios, 8 to 32. Expansion of laser ablated Delrin propellant appears to convert the absorbed laser energy more efficiently to jet kinetic energy because the effective density of the ablated gaseous Delrin is significantly greater than that of STP air.

  13. Solar energy conversion through ligand photodissociation

    SciTech Connect

    Hoffman, B.M.; Sima, P.D.

    1983-04-06

    A new technique for photochemical conversion of solar energy based on ligand photodissociation from metal complexes is examined. The concept is illustrated with a photogalvanic cell in which voltages are generated by photodissociation of CO from carbonylferroheme and with a cell in which the illuminated electrode is coated with an iron tetraphenylporphyrin.

  14. Systems and methods for wave energy conversion

    DOEpatents

    MacDonald, Daniel G.; Cantara, Justin; Nathan, Craig; Lopes, Amy M.; Green, Brandon E.

    2017-02-28

    Systems for wave energy conversion that have components that can survive the harsh marine environment and that can be attached to fixed structures, such as a pier, and having the ability to naturally adjust for tidal height and methods for their use are presented.

  15. Concrete for Ocean Thermal Energy, Conversion Structures.

    DTIC Science & Technology

    1976-08-01

    construction of massive floating structures to house ocean thermal energy conversion ( OTEC ) systems. The relevant capabilities and limitations of available...which reasonable improvements can be made in the near term to provide greater assurances of long-term safe and reliable operation of the OTEC systems and to provide lower cost structures. (Author)

  16. The power of thermionic energy conversion

    SciTech Connect

    Ramalingam, M.L. ); Young, T.J. . Aerospace Power Div.)

    1993-09-01

    This article is a technology assessment of thermionic energy conversion. The topics of the article include current thermionic programs, application to planned military and civilian space missions, USA and former Soviet Union cooperation in thermionic developmental activities, the Topaz program, types of converters, emitter developments, demonstrating readiness, and ionization media developments.

  17. Ocean Thermal Energy Conversion: An overview

    SciTech Connect

    Not Available

    1989-11-01

    Ocean thermal energy conversion, or OTEC is a technology that extracts power from the ocean's natural thermal gradient. This technology is being pursued by researchers from many nations; in the United States, OTEC research is funded by the US Department of Energy's Ocean Energy Technology program. The program's goal is to develop the technology so that industry can make a competent assessment of its potential -- either as an alternative or as a supplement to conventional energy sources. Federally funded research in components and systems will help OTEC to the threshold of commercialization. This publication provides an overview of the OTEC technology. 47 refs., 25 figs.

  18. Ocean thermal energy conversion: An overview

    NASA Astrophysics Data System (ADS)

    1989-11-01

    Ocean thermal energy conversion, or OTEC is a technology that extracts power from the ocean's natural thermal gradient. This technology is being pursued by researchers from many nations; in the United States, OTEC research is funded by the U.S. Department of Energy's Ocean Energy Technology program. The program's goal is to develop the technology so that industry can make a competent assessment of its potential; either as an alternative or as a supplement to conventional energy sources. Federally funded research in components and systems will help OTEC to the threshold of commercialization. An overview of the OTEC technology is provided.

  19. Optical Energy Transfer and Conversion System

    NASA Technical Reports Server (NTRS)

    Stone, William C. (Inventor); Hogan, Bartholomew P. (Inventor)

    2015-01-01

    An optical power transfer system comprising a fiber spooler, a fiber optic rotary joint mechanically connected to the fiber spooler, and an electrical power extraction subsystem connected to the fiber optic rotary joint with an optical waveguide. Optical energy is generated at and transferred from a base station through fiber wrapped around the spooler, through the rotary joint, and ultimately to the power extraction system at a remote mobility platform for conversion to another form of energy.

  20. Energy transfer processes in solar energy conversion

    SciTech Connect

    Fayer, M.D.

    1986-11-01

    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.

  1. Semiconducting materials for photoelectrochemical energy conversion

    NASA Astrophysics Data System (ADS)

    Sivula, Kevin; van de Krol, Roel

    2016-02-01

    To achieve a sustainable society with an energy mix primarily based on solar energy, we need methods of storing energy from sunlight as chemical fuels. Photoelectrochemical (PEC) devices offer the promise of solar fuel production through artificial photosynthesis. Although the idea of a carbon-neutral energy economy powered by such ‘artificial leaves’ is intriguing, viable PEC energy conversion on a global scale requires the development of devices that are highly efficient, stable and simple in design. In this Review, recently developed semiconductor materials for the direct conversion of light into fuels are scrutinized with respect to their atomic constitution, electronic structure and potential for practical performance as photoelectrodes in PEC cells. The processes of light absorption, charge separation and transport, and suitable energetics for energy conversion in PEC devices are emphasized. Both the advantageous and unfavourable aspects of multinary oxides, oxynitrides, chalcogenides, classic semiconductors and carbon-based semiconductors are critically considered on the basis of their experimentally demonstrated performance and predicted properties.

  2. Conversion of radiant light energy in photobioreactors

    SciTech Connect

    Cornet, J.F.; Dussap, C.G.; Gros, J.B. . Lab. de Genie Chimique Biologique)

    1994-06-01

    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.

  3. Approaches for biological and biomimetic energy conversion

    PubMed Central

    LaVan, David A.; Cha, Jennifer N.

    2006-01-01

    This article highlights areas of research at the interface of nanotechnology, the physical sciences, and biology that are related to energy conversion: specifically, those related to photovoltaic applications. Although much ongoing work is seeking to understand basic processes of photosynthesis and chemical conversion, such as light harvesting, electron transfer, and ion transport, application of this knowledge to the development of fully synthetic and/or hybrid devices is still in its infancy. To develop systems that produce energy in an efficient manner, it is important both to understand the biological mechanisms of energy flow for optimization of primary structure and to appreciate the roles of architecture and assembly. Whether devices are completely synthetic and mimic biological processes or devices use natural biomolecules, much of the research for future power systems will happen at the intersection of disciplines. PMID:16567648

  4. Novel Nuclear Powered Photocatalytic Energy Conversion

    SciTech Connect

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

    2005-08-29

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

  5. Sunlight-into-energy conversion apparatus

    SciTech Connect

    Kuwano, Y.; Yamano, M.

    1982-06-08

    The present application discloses a sunlight-into-energy conversion apparatus in which at least one amorphous silicon solar cell having a thickness thin enough to permit the sunlight to pass therethrough is formed on the surface of a heat collecting plate attached to a heating medium tube in a thermal conductive manner, thereby permitting the sunlight to be effectively converted into thermal energy and electrical energy. When a plurality of such amorphous silicon solar cells are formed on the surface of the heat collecting plate through insulating films, respectively and connected in series to each other, high electromotive force may be obtained.

  6. Bio-Inspired Solar Energy Conversion

    NASA Astrophysics Data System (ADS)

    Warncke, Kurt

    2009-11-01

    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 encompassed by natural photosynthesis offer molecular paradigms for efficient free energy capture and storage. We seek to emulate these features in cell-free, protein-based systems. Our goal is to transform the robust (alpha,beta)8-barrel fold of an enzyme that naturally catalyzes radical reactions into a catalytic module for the reduction of carbon dioxide to formate, by using the cobalt-containing cobalamins and other organocobalt centers. The activation of the catalytic center will be driven by photo-reduction, by using soluble and attached organic or semiconductor architectures. Progress on the biochemical, chemical, physical, and molecular biological (including rational design of high binding affinity and reactivity towards carbon dioxide) approaches to the development of the photocatalytic system will be presented.[4pt] [1] Lewis, N.; Crabtree, G. In: Basic Research Needs for Solar Energy Utilization, Basic Energy Sciences Workshop on Solar Energy Utilization, Energy, U.S. Department of Energy, Office of Science: 2005.

  7. Environmental impacts of ocean thermal energy conversion

    SciTech Connect

    Not Available

    1986-04-01

    Ocean thermal energy conversion (OTEC) is a promising technology for production of energy and usable by-products from solar-generated temperature gradients in the world's oceans. Although considered benign compared to alternative forms of energy generation, deployment of OTEC plants will result in interactions with marine, terrestrial, and atmospheric environments and in socioeconomic interactions with surrounding areas. The Ocean Energy Technology Program of the Department of Energy has funded research to improve the understanding of these interactions. No insurmountable environmental obstacle to OTEC deployment has been uncovered. This document contains a summary of that research for entrepreneurs, utility engineers, and others interested in pursuing OTEC's potential. In addition, it provides a guide to permits, regulations, and licenses applicable to construction of an OTEC plant.

  8. Multifunctional Energy Storage and Conversion Devices.

    PubMed

    Huang, Yan; Zhu, Minshen; Huang, Yang; Pei, Zengxia; Li, Hongfei; Wang, Zifeng; Xue, Qi; Zhi, Chunyi

    2016-10-01

    Multifunctional energy storage and conversion devices that incorporate novel features and functions in intelligent and interactive modes, represent a radical advance in consumer products, such as wearable electronics, healthcare devices, artificial intelligence, electric vehicles, smart household, and space satellites, etc. Here, smart energy devices are defined to be energy devices that are responsive to changes in configurational integrity, voltage, mechanical deformation, light, and temperature, called self-healability, electrochromism, shape memory, photodetection, and thermal responsivity. Advisable materials, device designs, and performances are crucial for the development of energy electronics endowed with these smart functions. Integrating these smart functions in energy storage and conversion devices gives rise to great challenges from the viewpoint of both understanding the fundamental mechanisms and practical implementation. Current state-of-art examples of these smart multifunctional energy devices, pertinent to materials, fabrication strategies, and performances, are highlighted. In addition, current challenges and potential solutions from materials synthesis to device performances are discussed. Finally, some important directions in this fast developing field are considered to further expand their application.

  9. Energy conversion in the coronal plasma

    NASA Technical Reports Server (NTRS)

    Martens, P. C. H.

    1986-01-01

    Solar and stellar X-ray emission are the observed waste products of the interplay between magnetic fields and the motion of stellar plasma. Theoretical understanding of the process of coronal heating is of utmost importance, since the high temperature is what defines the corona in the first place. Most of the research described deals with the aspects of the several rivalling theories for coronal heating. The rest of the papers deal with processes of energy conversion related to flares.

  10. In-Flight Measurement of the Absolute Energy Scale of the Fermi Large Area Telescope

    SciTech Connect

    Ackermann, M.; Ajello, M.; Allafort, A.; Atwood, W.B.; Axelsson, M.; Baldini, L.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Bloom, E.D.; Bonamente, E.; Borgland, A.W.; Bouvier, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Buehler, R.; Buson, S.; /more authors..

    2012-09-20

    The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope is a pair-conversion telescope designed to survey the gamma-ray sky from 20 MeV to several hundreds of GeV. In this energy band there are no astronomical sources with sufficiently well known and sharp spectral features to allow an absolute calibration of the LAT energy scale. However, the geomagnetic cutoff in the cosmic ray electron-plus-positron (CRE) spectrum in low Earth orbit does provide such a spectral feature. The energy and spectral shape of this cutoff can be calculated with the aid of a numerical code tracing charged particles in the Earth's magnetic field. By comparing the cutoff value with that measured by the LAT in different geomagnetic positions, we have obtained several calibration points between {approx}6 and {approx}13 GeV with an estimated uncertainty of {approx}2%. An energy calibration with such high accuracy reduces the systematic uncertainty in LAT measurements of, for example, the spectral cutoff in the emission from gamma ray pulsars.

  11. In-Flight Measurement of the Absolute Energy Scale of the Fermi Large Area Telescope

    NASA Technical Reports Server (NTRS)

    Ackermann, M.; Ajello, M.; Allafort, A.; Atwood, W. B.; Axelsson, M.; Baldini, L.; Barbielini, G; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B,; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bouvier, A.; Bregeon, J.; Brez, A.; Brigida, M.; Bruel, P.; Buehler, R.; Gehrels, N.; Hays, E.; McEnery, J. E.; Thompson, D. J.; Troja, E. J.

    2012-01-01

    The Large Area Telescope (LAT) on-board the Fermi Gamma-ray Space Telescope is a pair-conversion telescope designed to survey the gamma-ray sky from 20 MeV to several hundreds of GeV. In this energy band there are no astronomical sources with sufficiently well known and sharp spectral features to allow an absolute calibration of the LAT energy scale. However, the geomagnetic cutoff in the cosmic ray electron- plus-positron (CRE) spectrum in low Earth orbit does provide such a spectral feature. The energy and spectral shape of this cutoff can be calculated with the aid of a numerical code tracing charged particles in the Earth's magnetic field. By comparing the cutoff value with that measured by the LAT in different geomagnetic positions, we have obtained several calibration points between approx. 6 and approx. 13 GeV with an estimated uncertainty of approx. 2%. An energy calibration with such high accuracy reduces the systematic uncertainty in LAT measurements of, for example, the spectral cutoff in the emission from gamma ray pulsars.

  12. Nanoscale Materials and Architectures for Energy Conversion

    SciTech Connect

    Grulke, Eric A.; Sunkara, Mahendra K.

    2011-05-25

    The Kentucky EPSCoR Program supported an inter-university, multidisciplinary energy-related research cluster studying nanomaterials for converting solar radiation and residual thermal energy to electrical energy and hydrogen. It created a collaborative center of excellence based on research expertise in nanomaterials, architectures, and their synthesis. The project strengthened and improved the collaboration between the University of Louisville, the University of Kentucky, and NREL. The cluster hired a new faculty member for ultra-fast transient spectroscopy, and enabled the mentoring of one research scientist, two postdoctoral scholars and ten graduate students. Work was accomplished with three focused cluster projects: organic and photoelectrochemical solar cells, solar fuels, and thermionic energy conversion.

  13. Ocean thermal energy conversion: Materials issues

    NASA Astrophysics Data System (ADS)

    Darby, J. B., Jr.

    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.

  14. Innovative oxide materials for electrochemical energy conversion

    NASA Astrophysics Data System (ADS)

    Wachsman, Eric D.

    2012-02-01

    Research in functional materials has progressed from those materials exhibiting structural to electronic functionality. The study of ion conducting ceramics ushers in a new era of ``chemically functional materials.'' This chemical functionality arises out of the defect equilibria of these materials, and results in the ability to transport chemical species and actively participate in chemical reactions at their surface. Moreover, this chemical functionality provides a promise for the future whereby the harnessing of our natural hydrocarbon energy resources can shift from inefficient and polluting combustion - mechanical methods to direct electrochemical conversion. The unique properties of these materials and their applications will be described. The focus will be on the application of ion conducting ceramics to energy conversion and storage, chemical sensors, chemical separation and conversion, and life support systems. Results presented will include development of record high power density (3 kW/kg) solid oxide fuel cells, NOx/CO species selective solid-state sensors, high yield membrane reactors, and regenerative life support systems that reduce CO2 to O2 and solid C.

  15. Solar thermochemical energy conversion and transport

    NASA Astrophysics Data System (ADS)

    McCrary, J. H.; McCrary, G. E.

    1982-11-01

    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 and operated on the NMSU campus. A number of receiver elements (chemical reactors) have been tested in these laboratory facilities in an effort to optimize catalyst parameters and catalyst reactor configurations. These tests led to the design and fabrication of both low power and high power solar energy receivers which were operated successfully at the White Sands solar Furnace. Energy delivery methanation reactor design and parametric studies led to the fabrication and operation of laboratory closed-loop, energy conversion, transport, and delivery system. These latter experiments met with limited but promising success. Carbon deposition, though a problem, is believed to be controllable with the optimization of catalyst parameters and feedstock composition.

  16. Ocean energy conversion systems annual research report

    SciTech Connect

    Not Available

    1981-03-01

    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.

  17. Thermophotovoltaic Energy Conversion for Space Applications

    NASA Astrophysics Data System (ADS)

    Teofilo, V. L.; Choong, P.; Chen, W.; Chang, J.; Tseng, Y.-L.

    2006-01-01

    Thermophotovoltaic (TPV) energy conversion cells have made steady and over the years considerable progress since first evaluated by Lockheed Martin for direct conversion using nuclear power sources in the mid 1980s. The design trades and evaluations for application to the early defensive missile satellites of the Strategic Defense Initiative found the cell technology to be immature with unacceptably low cell efficiencies comparable to thermoelectric of <10%. Rapid advances in the epitaxial growth technology for ternary compound semiconductors, novel double hetero-structure junctions, innovative monolithic integrated cell architecture, and bandpass tandem filter have, in concert, significantly improved cell efficiencies to 25% with the promise of 35% using solar cell like multi-junction approach in the near future. Recent NASA sponsored design and feasibility testing programs have demonstrated the potential for 19% system efficiency for 100 We radioisotopic power sources at an integrated specific power of ~14 We/kg. Current state of TPV cell technology however limits the operating temperature of the converter cells to < 400K due to radiator mass consideration. This limitation imposes no system mass penalty for the low power application for use with radioisotopes power sources because of the high specific power of the TPV cell converters. However, the application of TPV energy conversion for high power sources has been perceived as having a major impediment above 1 kWe due to the relative low waste heat rejection temperature. We explore this limitation and compare the integrated specific power of TPV converters with current and projected TPV cells with other advanced space power conversion technologies. We find that when the redundancy needed required for extended space exploration missions is considered, the TPV converters have a much higher range of applicability then previously understood. Furthermore, we believe that with a relatively modest modifications of the

  18. Energy conversion device with improved seal

    DOEpatents

    Miller, Gerald R.; Virkar, Anil V.

    1980-01-01

    An energy conversion device comprising an improved sealing member adapted to seal a cation-permeable casing to the remainder of the device. The sealing member comprises a metal substrate which (i) bears a nonconductive and corrosion resistant coating on the major surface to which said casing is sealed, and (ii) is corrugated so as to render it flexible, thereby allowing said member to move relative to said casing without cracking the seal therebetween. Corrugations may be circumferential, radial, or both radial and circumferential so as to form dimples. The corrugated member may be in form of a bellows or in a substantially flat form, such as a disc.

  19. Carbon aerogel electrodes for direct energy conversion

    DOEpatents

    Mayer, S.T.; Kaschmitter, J.L.; Pekala, R.W.

    1997-02-11

    A direct energy conversion device, such as a fuel cell, using carbon aerogel electrodes is described, wherein the carbon aerogel is loaded with a noble catalyst, such as platinum or rhodium and soaked with phosphoric acid, for example. A separator is located between the electrodes, which are placed in a cylinder having plate current collectors positioned adjacent the electrodes and connected to a power supply, and a pair of gas manifolds, containing hydrogen and oxygen positioned adjacent the current collectors. Due to the high surface area and excellent electrical conductivity of carbon aerogels, the problems relative to high polarization resistance of carbon composite electrodes conventionally used in fuel cells are overcome. 1 fig.

  20. Carbon aerogel electrodes for direct energy conversion

    DOEpatents

    Mayer, Steven T.; Kaschmitter, James L.; Pekala, Richard W.

    1997-01-01

    A direct energy conversion device, such as a fuel cell, using carbon aerogel electrodes, wherein the carbon aerogel is loaded with a noble catalyst, such as platinum or rhodium and soaked with phosphoric acid, for example. A separator is located between the electrodes, which are placed in a cylinder having plate current collectors positioned adjacent the electrodes and connected to a power supply, and a pair of gas manifolds, containing hydrogen and oxygen positioned adjacent the current collectors. Due to the high surface area and excellent electrical conductivity of carbon aerogels, the problems relative to high polarization resistance of carbon composite electrodes conventionally used in fuel cells are overcome.

  1. Method for conversion of chemical energy to electric energy

    SciTech Connect

    Kodama, T.; Nakamura, O.; Ogino, I.

    1983-04-19

    In the conversion of chemical energy into electric energy by the electrochemical reaction of a gaseous anodic reactant and a gaseous cathodic reactant through the medium of a heteropoly acid solid electrolyte, the life of the solid electrolyte is notably increased by passing each reactant through pools of a saturated aqueous solution of a specific salt bordering on closed empty spaces thereby allowing the reactants to acquire prescribed humidities prior to the contact thereof with the anode and cathode.

  2. OCEAN THERMAL ENERGY CONVERSION PROGRAMMATIC ENVIRONMENTAL ASSESSMENT

    SciTech Connect

    Sands, M. Dale

    1980-08-01

    Significant achievements in Ocean Thermal Energy Conversion (OTEC) technology have increased the probability of producing OTEC-derived power in this decade with subsequent large-scale commercialization to follow by the turn of the century. Under U.S. Department of Energy funding, Interstate Electronics has prepared an OTEC Programmatic Environmental Assessment (EA) that considers tne development, demonstration, and commercialization of OTEC power systems. The EA considers several tecnnological designs (open cycle and closed cycle), plant configurations (land-based, moored, and plantship), and power usages (baseload electricity and production of ammonia and aluminum). Potencial environmental impacts, health and safety issues, and a status update of international, federal, and state plans and policies, as they may influence OTEC deployments, are included.

  3. Black metallurgical silicon for solar energy conversion

    NASA Astrophysics Data System (ADS)

    Li, Xiaopeng; Lee, Jung-Ho; Sprafke, Alexander N.; Wehrspohn, Ralf B.

    2016-01-01

    Metal impurities are known to create deep traps in the silicon (Si) bandgap, significantly reducing the minority carrier lifetime and consequently deteriorating the efficiency of a Si-based solar conversion system. Traditional purification methods via ‘Siemens’ and metallurgical routes involve complex and energy-intensive processes. Therefore, it is highly desirable to develop novel Si treatment technologies. With the radical evolution of nanotechnology in the past decades, new nano-approaches are offering opportunities to diminish the detrimental impacts of metal impurities or upgrade low quality Si in a cost-effective and energy-saving way. Here we review various recently developed dry and wet chemical etching methods including reactive ion etching, electrochemical etching, stain etching and metal assisted chemical etching. The current progress and the application prospects of those methods in nanostructure creation and Si upgrading are given and discussed in detail.

  4. Conversion of blackbody radiation into laser energy

    NASA Astrophysics Data System (ADS)

    McInville, R. M.; Hassan, H. A.

    1982-06-01

    By employing detailed kinetic models, three concepts which utilize a blackbody cavity for the conversion of solar energy into laser energy using a CO2 lasant are analyzed and compared. In the first, the blackbody radiation is used to excite flowing CO2 directly. The second and third employ a mixing laser concept with CO and N2 being the donor gases. The CO is optically pumped while thermal heating excites the N2. Blackbody temperatures ranging from 1500 deg K - 2500 deg K are considered. Based on calculated laser power output per unit flow rate of CO2, it appears that the N2-CO2 mixing laser is the most attractive system.

  5. Wind energy conversion in the MW range

    NASA Astrophysics Data System (ADS)

    Lois, L.

    The purpose of this paper is threefold: (1) to show that certain wind patterns above the continental United States are particularly suited for wind energy conversion utilizing wind powered stations in the MWe range, (2) to describe a system specifically designed for such stations, and (3) to present calculations which show that such a system is within the range of existing technology. The proposed system is based on the existence of a wind pattern called the low level jet in which (a) the average wind speed is 2.0 to 3.0 times higher than at the 300 ft level, and (b) the diurnal and seasonal variations are smaller than at 300 ft. The higher specific power and utilization factor which result from the characteristics of the low level jet contribute to higher power level per installation and power cost per unit energy produced.

  6. Thermophotovoltaic energy conversion: Technology and market potential

    SciTech Connect

    Ostrowski, L.J.; Pernisz, U.C.; Fraas, L.M.

    1996-02-01

    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 {open_quote}{open_quote}moving down the learning curve,{close_quote}{close_quote} 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. {copyright} {ital 1996 American Institute of Physics.}

  7. Thermophotovoltaic energy conversion: Technology and market potential

    NASA Astrophysics Data System (ADS)

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

    1996-02-01

    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.

  8. Nanoscale Fluid Mechanics and Energy Conversion

    SciTech Connect

    Chen, X; Xu, BX; Liu, L

    2014-05-29

    Under nanoconfinement, fluid molecules and ions exhibit radically different configurations, properties, and energetics from those of their bulk counterparts. These unique characteristics of nanoconfined fluids, along with the unconventional interactions with solids at the nanoscale, have provided many opportunities for engineering innovation. With properly designed nanoconfinement, several nanofluidic systems have been devised in our group in the past several years to achieve energy conversion functions with high efficiencies. This review is dedicated to elucidating the unique characteristics of nanofluidics, introducing several novel nanofluidic systems combining nanoporous materials with functional fluids, and to unveiling their working mechanisms. In all these systems, the ultra-large surface area available in nanoporous materials provides an ideal platform for seamlessly interfacing with nanoconfined fluids, and efficiently converting energy between the mechanical, thermal, and electrical forms. These systems have been demonstrated to have great potentials for applications including energy dissipation/absorption, energy trapping, actuation, and energy harvesting. Their efficiencies can be further enhanced by designing efforts based upon improved understanding of nanofluidics, which represents an important addition to classical fluid mechanics. Through the few systems exemplified in this review, the emerging research field of nanoscale fluid mechanics may promote more exciting nanofluidic phenomena and mechanisms, with increasing applications by encompassing aspects of mechanics, materials, physics, chemistry, biology, etc.

  9. Technology assessment of wind energy conversion systems

    SciTech Connect

    Meier, B. W.; Merson, T. J.

    1980-09-01

    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 makes a significant contribution to the national energy requirements. One WECS is a large machine of 1.5-MW-rated capacity that can be used by utilities. The other WECS is a small machine that is characteristic of units that might be used to meet residential or small business energy requirements. Energy storage systems are discussed for each machine to address the intermittent nature of wind power. Many types of WECSs are being studied and a brief review of the technology is included to give background for choosing horizontal axis designs for this study. Cost estimates have been made for both large and small systems as required for input to the Strategic Environmental Assessment Simulation (SEAS) computer program. Material requirements, based on current generation WECSs, are discussed and a general discussion of environmental impacts associated with WECS deployment is presented.

  10. Compact harsh environment energy conversion systems

    NASA Astrophysics Data System (ADS)

    Ahmed, Shehab

    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.

  11. Solar energy conversion using surface plasmons for broadband energy transport

    NASA Technical Reports Server (NTRS)

    Anderson, L. M.

    1982-01-01

    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.

  12. Stretchable energy storage and conversion devices.

    PubMed

    Yan, Chaoyi; Lee, Pooi See

    2014-09-10

    Stretchable electronics are a type of mechanically robust electronics which can be bended, folded, crumpled and stretched and represent the emerging direction towards next-generation wearable and implantable devices. Unlike existing electronics based on rigid Si technologies, stretchable devices can conform to the complex non-coplanar surfaces and provide unique functionalities which are unreachable with simple extension of conventional technologies. Stretchable energy storage and conversion devices are the key components for the fabrication of complete and independent stretchable systems. In this review, we present the recent progresses in the developments of stretchable power sources including supercapacitors, batteries and solar cells. Representative structural and material designs to impart stretchability to the originally rigid devices are discussed. Advantages and drawbacks associated with the fabrication methods are also analysed. Summaries of the research progresses along with future development directions for this exciting field are also presented.

  13. Ocean Thermal Energy Conversion Act of 1980

    SciTech Connect

    Not Available

    1980-01-01

    A legislative proposal to develop ocean thermal energy conversion (OTEC) facilities for power generation was the subject of hearings held on April 10 and May 1, 1980. Following the test of S. 2492 are the statements of 20 witnesses and additional materials submitted for consideration. The need for a large-scale demonstration of OTEC and the need for a Federal regulatory, siting, and financial-assistance framework are the major commercialization issues. S. 2492 provides one-stop licensing by treating the facilities as vessels and making them eligible for loan guarantees. The bill complements S. 1430, which deals with the demonstration program. OTEC development in Hawaii has progressed to a second pilot project. (DCK)

  14. Thermoelectric energy conversion with solid electrolytes

    NASA Astrophysics Data System (ADS)

    Cole, T.

    1983-09-01

    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, 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.

  15. Thermoelectric energy conversion with solid electrolytes.

    PubMed

    Cole, T

    1983-09-02

    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.

  16. Power conversion from environmentally scavenged energy sources.

    SciTech Connect

    Druxman, Lee Daniel

    2007-09-01

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

  17. Theoretical efficiency limits for thermoradiative energy conversion

    SciTech Connect

    Strandberg, Rune

    2015-02-07

    A new method to produce electricity from heat called thermoradiative energy conversion is analyzed. The method is based on sustaining a difference in the chemical potential for electron populations above and below an energy gap and let this difference drive a current through an electric circuit. The difference in chemical potential originates from an imbalance in the excitation and de-excitation of electrons across the energy gap. The method has similarities to thermophotovoltaics and conventional photovoltaics. While photovoltaic cells absorb thermal radiation from a body with higher temperature than the cell itself, thermoradiative cells are hot during operation and emit a net outflow of photons to colder surroundings. A thermoradiative cell with an energy gap of 0.25 eV at a temperature of 500 K in surroundings at 300 K is found to have a theoretical efficiency limit of 33.2%. For a high-temperature thermoradiative cell with an energy gap of 0.4 eV, a theoretical efficiency close to 50% is found while the cell produces 1000 W/m{sup 2} has a temperature of 1000 K and is placed in surroundings with a temperature of 300 K. Some aspects related to the practical implementation of the concept are discussed and some challenges are addressed. It is, for example, obvious that there is an upper boundary for the temperature under which solid state devices can work properly over time. No conclusions are drawn with regard to such practical boundaries, because the work is aimed at establishing upper limits for ideal thermoradiative devices.

  18. Science of Nanofluidics and Energy Conversion

    NASA Astrophysics Data System (ADS)

    Xu, Baoxing

    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

  19. Identification of absolute conversion to geraldol from fisetin and pharmacokinetics in mouse.

    PubMed

    Jo, Jun Hyeon; Jo, Jung Jae; Lee, Jae-Mok; Lee, Sangkyu

    2016-12-01

    Fisetin (3,3',4',7-tetrahydroxyflavone) is a flavonoid found in several fruits, vegetables, nuts, and wine and has anti-oxidant, anti-inflammatory, and anti-angiogenic properties. Geraldol is the 3'-methoxylated metabolite of fisetin (3,4',7-trihydroxy-3'-methoxyflavone). The concentration of fisetin and geraldol in mouse plasma was determined by LC-MS/MS, following direct protein precipitation. These concentrations were determined after administration of fisetin at doses of 2mg/kg (i.v.) and 100 and 200mg/kg (p.o.). The method was validated in terms of linearity, accuracy, precision, matrix effect, and stability. The pharmacokinetics parameters of fisetin and geraldol were successfully determined using a validated method in mice. Results indicated that fisetin was very rapidly methylated to geraldol in vivo. Following administration of fisetin, it was observed that the Cmax and AUC values for geraldol were higher than those of fisetin. The absolute bioavailability of fisetin was calculated as 7.8% and 31.7% after oral administration of 100 and 200mg/kg fisetin, respectively. This method was successfully applied to determine the pharmacokinetic parameters of fisetin and its main metabolite geraldol in mouse plasma. Geraldol was the dominant circulating metabolite after fisetin administration in vivo.

  20. Absolute energy curves from late B-type supergiants

    NASA Technical Reports Server (NTRS)

    Underhill, A. B.

    1981-01-01

    Energy curves were determined for six late B and early A type supergiants using IUE data and other ultraviolet and ground based photometry. Effective temperatures and angular diameters are presented as well as estimates of the outflow velocity of the wind. All six stars show a strong Balmer continuum in emission; the Ia supergiants also show an infrared excess which reaches into the visible range. Evidence is found for the presence of a warm mantle as well as for wind from the Ia stars.

  1. Ocean thermal energy conversion: Perspective and status

    SciTech Connect

    Thomas, A.; Hillis, D.L.

    1990-01-01

    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.

  2. Ocean thermal energy conversion: Perspective and status

    NASA Astrophysics Data System (ADS)

    Thomas, Anthony; Hillis, David L.

    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.

  3. Conversion of laser energy to gas kinetic energy

    NASA Technical Reports Server (NTRS)

    Caledonia, G. E.

    1977-01-01

    Techniques for the gas-phase absorption of laser energy with ultimate conversion to heat or directed kinetic energy are reviewed. It is shown that the efficiency of resonance absorption by the vibration/rotation bands of the working gas can be enhanced by operating at sufficiently high pressures so that the linewidths of the absorbing transition exceed the line spacing. Within this limit, the gas can absorb continuously over the full spectral region of the band, and bleaching can be minimized since the manifold of molecular vibrational levels can simultaneously absorb the laser radiation.

  4. Status of thermoelectronic laser energy conversion, TELEC

    NASA Technical Reports Server (NTRS)

    Britt, E. J.

    1982-01-01

    A concept known as a thermo-electronic laser energy converter (TELEC), was studied as a method of converting a 10.6 micron CO2 laser beam into electric power. The calculated characteristics of a TELEC seem to be well matched to the requirements of a spacecraft laser energy conversion system. The TELEC is a high power density plasma device which absorbs an intense laser beam by inverse bremsstrahlung with the plasma electrons. In the TELEC process, electromagnetic radiation is absorbed directly in the plasma electrons producing a high electron temperature. The energetic electrons diffuse out of the plasma striking two electrodes which are in contact with the plasma at the boundaries. These two electrodes have different areas: the larger one is designated as the collector, the smaller one is designated as the emitter. The smaller electrode functions as an electron emitter provide continuity of the current. Waste heat is rejected from the collector electrode. An experiment was carried out with a high power laser using a cesium vapor TELEC cell with 30 cm active length. Laser supported plasma were produced in the TELEC device during a number of laser runs over a period of several days. Electric power from the TELEC was observed with currents in the range of several amperes and output potentials of less than 1 volt.

  5. Fundamental formulae for wave-energy conversion.

    PubMed

    Falnes, Johannes; Kurniawan, Adi

    2015-03-01

    The time-average wave power that is absorbed from an incident wave by means of a wave-energy conversion (WEC) unit, or by an array of WEC units-i.e. oscillating immersed bodies and/or oscillating water columns (OWCs)-may be mathematically expressed in terms of the WEC units' complex oscillation amplitudes, or in terms of the generated outgoing (diffracted plus radiated) waves, or alternatively, in terms of the radiated waves alone. Following recent controversy, the corresponding three optional expressions are derived, compared and discussed in this paper. They all provide the correct time-average absorbed power. However, only the first-mentioned expression is applicable to quantify the instantaneous absorbed wave power and the associated reactive power. In this connection, new formulae are derived that relate the 'added-mass' matrix, as well as a couple of additional reactive radiation-parameter matrices, to the difference between kinetic energy and potential energy in the water surrounding the immersed oscillating WEC array. Further, a complex collective oscillation amplitude is introduced, which makes it possible to derive, by a very simple algebraic method, various simple expressions for the maximum time-average wave power that may be absorbed by the WEC array. The real-valued time-average absorbed power is illustrated as an axisymmetric paraboloid defined on the complex collective-amplitude plane. This is a simple illustration of the so-called 'fundamental theorem for wave power'. Finally, the paper also presents a new derivation that extends a recently published result on the direction-average maximum absorbed wave power to cases where the WEC array's radiation damping matrix may be singular and where the WEC array may contain OWCs in addition to oscillating bodies.

  6. Fundamental formulae for wave-energy conversion

    PubMed Central

    Falnes, Johannes; Kurniawan, Adi

    2015-01-01

    The time-average wave power that is absorbed from an incident wave by means of a wave-energy conversion (WEC) unit, or by an array of WEC units—i.e. oscillating immersed bodies and/or oscillating water columns (OWCs)—may be mathematically expressed in terms of the WEC units' complex oscillation amplitudes, or in terms of the generated outgoing (diffracted plus radiated) waves, or alternatively, in terms of the radiated waves alone. Following recent controversy, the corresponding three optional expressions are derived, compared and discussed in this paper. They all provide the correct time-average absorbed power. However, only the first-mentioned expression is applicable to quantify the instantaneous absorbed wave power and the associated reactive power. In this connection, new formulae are derived that relate the ‘added-mass’ matrix, as well as a couple of additional reactive radiation-parameter matrices, to the difference between kinetic energy and potential energy in the water surrounding the immersed oscillating WEC array. Further, a complex collective oscillation amplitude is introduced, which makes it possible to derive, by a very simple algebraic method, various simple expressions for the maximum time-average wave power that may be absorbed by the WEC array. The real-valued time-average absorbed power is illustrated as an axisymmetric paraboloid defined on the complex collective-amplitude plane. This is a simple illustration of the so-called ‘fundamental theorem for wave power’. Finally, the paper also presents a new derivation that extends a recently published result on the direction-average maximum absorbed wave power to cases where the WEC array's radiation damping matrix may be singular and where the WEC array may contain OWCs in addition to oscillating bodies. PMID:26064612

  7. Organohalide Perovskites for Solar Energy Conversion.

    PubMed

    Lin, Qianqian; Armin, Ardalan; Burn, Paul L; Meredith, Paul

    2016-03-15

    Lead-based organohalide perovskites have recently emerged as arguably the most promising of all next generation thin film solar cell technologies. Power conversion efficiencies have reached 20% in less than 5 years, and their application to other optoelectronic device platforms such as photodetectors and light emitting diodes is being increasingly reported. Organohalide perovskites can be solution processed or evaporated at low temperatures to form simple thin film photojunctions, thus delivering the potential for the holy grail of high efficiency, low embedded energy, and low cost photovoltaics. The initial device-driven "perovskite fever" has more recently given way to efforts to better understand how these materials work in solar cells, and deeper elucidation of their structure-property relationships. In this Account, we focus on this element of organohalide perovskite chemistry and physics in particular examining critical electro-optical, morphological, and architectural phenomena. We first examine basic crystal and chemical structure, and how this impacts important solar-cell related properties such as the optical gap. We then turn to deeper electronic phenomena such as carrier mobilities, trap densities, and recombination dynamics, as well as examining ionic and dielectric properties and how these two types of physics impact each other. The issue of whether organohalide perovskites are predominantly nonexcitonic at room temperature is currently a matter of some debate, and we summarize the evidence for what appears to be the emerging field consensus: an exciton binding energy of order 10 meV. Having discussed the important basic chemistry and physics we turn to more device-related considerations including processing, morphology, architecture, thin film electro-optics and interfacial energetics. These phenomena directly impact solar cell performance parameters such as open circuit voltage, short circuit current density, internal and external quantum efficiency

  8. Demonstrating Energy Conversion with Piezoelectric Crystals and a Paddle Fan

    ERIC Educational Resources Information Center

    Rakbamrung, Prissana; Putson, Chatchai; Muensit, Nantakan

    2014-01-01

    A simple energy conversion system--particularly, the conversion of mechanical energy into electrical energy by using shaker flashlights--has recently been presented. This system uses hand generators, consisting of a magnet in a tube with a coil wrapped around it, and acts as an ac source when the magnet passes back and forth through the coil.…

  9. Radiative energy receiver for high performance energy conversion cycles

    NASA Technical Reports Server (NTRS)

    Rault, D.; Hertzberg, A.

    1982-01-01

    An analysis of gas dynamic processes pertinent to the functioning of earth-based and space-based solar electric power plants is presented, with attention given to potassium vapor as the working fluid. A device is described which features focused photon absorption by a nontransparent flowing gas. The feed flow is effected around the outside walls of a cavity receiver to raise efficiencies by trapping reemitted energy. A theoretical study of the interaction of a photon flux with a coaxial particle flux was performed, with the receiver flow treated as a Graetz flow. The critical parameters were defined, including a figure of merit as the gas enthalpy increase to absorbable energy ratio. A small-scale laboratory model was tested in comparison with the theoretically obtained values. Less than 15% of the absorbed energy was lost through dissipation while an 80% conversion efficiency was attained.

  10. Conversion of poultry wastes into energy feedstocks.

    PubMed

    Kantarli, Ismail Cem; Kabadayi, Arzu; Ucar, Suat; Yanik, Jale

    2016-10-01

    In this study, conversion of wastes from poultry farming and industry into biochar and bio-oil via thermochemical processes was investigated. Fuel characteristics and chemical structure of biochars and bio-oils have been investigated using standard fuel analysis and spectroscopic methods. Biochars were produced from poultry litter through both hydrothermal carbonization (sub-critical water, 175-250°C) and pyrolysis over a temperature range between 250 and 500°C. In comparison to hydrothermal carbonization, pyrolysis at lower temperatures produced biochar with greater energy yield due to the higher mass yield. Biochars obtained by both processes were comparable to coal. Hydrothermal liquefaction of poultry meal at different temperatures (200-325°C) was conducted and compared to optimize its process conditions. Higher temperatures favored the formation of bio-crude oil, with a maximum yield of 35wt.% at 300°C. The higher heating values of bio-oils showed that bio-oil could be a potential source of synthetic fuels. However, elemental analysis demonstrated the high nitrogen content of bio-oils. Therefore, bio-oils obtained from hydrothermal liquefaction of poultry meal should be upgraded for utilization as a transport and heating fuel.

  11. Direct Energy Conversion for Fast Reactors

    SciTech Connect

    Brown, N.; Cooper, J.; Vogt, D.; Chapline, G.; Turchi, P.; Barbee Jr., T.; Farmer, J.

    2000-07-01

    Thermoelectric generators (TEG) are a well-established technology for compact low power output long-life applications. Solid state TEGs are the technology of choice for many space missions and have also been used in remote earth-based applications. Since TEGs have no moving parts and can be hermetically sealed, there is the potential for nuclear reactor power systems using TEGs to be safe, reliable and resistant to proliferation. Such power units would be constructed in a manner that would provide decades of maintenance-free operation, thereby minimizing the possibility of compromising the system during routine maintenance operations. It should be possible to construct an efficient direct energy conversion cascade from an appropriate combination of solid-state thermoelectric generators, with each stage in the cascade optimized for a particular range of temperature. Performance of cascaded thermoelectric devices could be further enhanced by exploitation of compositionally graded p-n couples, as well as radial elements to maximize utilization of the heat flux. The Jet Propulsion Laboratory in Pasadena has recently reported segmented unicouples that operate between 300 and 975 K and have conversion efficiencies of 15 percent [Caillat, 2000]. TEGs are used in nuclear-fueled power sources for space exploration, in power sources for the military, and in electrical generators on diesel engines. Second, there is a wide variety of TE materials applicable to a broad range of temperatures. New materials may lead to new TEG designs with improved thermoelectric properties (i.e. ZT approaching 3) and significantly higher efficiencies than in designs using currently available materials. Computational materials science (CMS) has made sufficient progress and there is promise for using these techniques to reduce the time and cost requirements to develop such new TE material combinations. Recent advances in CMS, coupled with increased computational power afforded by the Accelerated

  12. Ultraviolet photometry from the Orbiting Astronomical Observatory. XXI - Absolute energy distribution of stars in the ultraviolet

    NASA Technical Reports Server (NTRS)

    Bless, R. C.; Code, A. D.; Fairchild, E. T.

    1976-01-01

    The absolute energy distribution in the ultraviolet is given for the stars alpha Vir, eta UMa, and alpha Leo. The calibration is based on absolute heterochromatic photometry between 2920 and 1370 A carried out with an Aerobee sounding rocket. The fundamental radiation standard is the synchrotron radiation from 240-MeV electrons in a certain synchrotron storage ring. On the basis of the sounding-rocket calibration, the preliminary OAO-2 spectrometer calibration has been revised; the fluxes for the three program stars are tabulated in energy per second per square centimeter per unit wavelength interval.

  13. Superharp: A wire scanner with absolute position readout for beam energy measurement at CEBAF

    SciTech Connect

    Yan, C.

    1994-09-07

    Superharp is an upgrade CEBAF wire scanner with absolute position readout from shaft encoder. As high precision absolute beam position probe ({Delta}x {approximately} 10{mu}m), three pairs of superharps are installed at the entrance, the mid-point, and the exit of Hall C arc beamline in beam switch yard, which will be tuned in dispersive mode as energy spectrometer performing 10{sup {minus}3} beam energy measurement. With dual sensor system: the direct current pickup and the bremsstrahlung detection electronics, beam profile can be obtained by superharp at wide beam current range from 1 {mu}A to 100 {mu}A.

  14. Absolute Binding Energies of Core Levels in Solids from First Principles

    NASA Astrophysics Data System (ADS)

    Ozaki, Taisuke; Lee, Chi-Cheng

    2017-01-01

    A general method is presented to calculate absolute binding energies of core levels in metals and insulators, based on a penalty functional and an exact Coulomb cutoff method in the framework of density functional theory. The spurious interaction of core holes between supercells is avoided by the exact Coulomb cutoff method, while the variational penalty functional enables us to treat multiple splittings due to chemical shift, spin-orbit coupling, and exchange interaction on equal footing, both of which are not accessible by previous methods. It is demonstrated that the absolute binding energies of core levels for both metals and insulators are calculated by the proposed method in a mean absolute (relative) error of 0.4 eV (0.16%) for eight cases compared to experimental values measured with x-ray photoemission spectroscopy within a generalized gradient approximation to the exchange-correlation functional.

  15. Open cycle ocean thermal energy conversion system

    DOEpatents

    Wittig, J. Michael

    1980-01-01

    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.

  16. Conversion of laser energy to gas kinetic energy

    NASA Technical Reports Server (NTRS)

    Caledonia, G. E.

    1975-01-01

    Techniques for the gas phase absorption of laser radiation for conversion to gas kinetic energy are discussed. Absorption by inverse Bremsstrahlung, in which laser energy is converted at a gas kinetic rate in a spectrally continuous process, is briefly described, and absorption by molecular vibrational rotation bands is discussed at length. High pressure absorption is proposed as a means of minimizing gas bleaching and dissociation, the major disadvantages of the molecular absorption process. A band model is presented for predicting the molecular absorption spectra in the high pressure absorption region and is applied to the CO molecule. Use of a rare gas seeded with Fe(CO)5 for converting vibrational modes to translation modes is described.

  17. Thermal noise can facilitate energy conversion by a ratchet system.

    PubMed

    Takagi, F; Hondou, T

    1999-10-01

    Molecular motors in biological systems are expected to use ambient fluctuation. In a recent paper [Phys. Rev. Lett. 80, 5251 (1998)], it was shown that the following question was unanswered: Can thermal noise facilitate energy conversion by ratchet system? We consider it using stochastic energetics, and show that there exist systems where thermal noise helps the energy conversion.

  18. Integrated microfluidic test-bed for energy conversion devices.

    PubMed

    Modestino, Miguel A; Diaz-Botia, Camilo A; Haussener, Sophia; Gomez-Sjoberg, Rafael; Ager, Joel W; Segalman, Rachel A

    2013-05-21

    Energy conversion devices require the parallel functionality of a variety of components for efficient operation. We present a versatile microfluidic test-bed for facile testing of integrated catalysis and mass transport components for energy conversion via water electrolysis. This system can be readily extended to solar-fuels generators and fuel-cell devices.

  19. A Metric (SI) Energy Scale: Conversions and Comparisons

    ERIC Educational Resources Information Center

    Petrakis, L.

    1974-01-01

    An energy scale, constructed in terms of the Joule, is presented. It provides for the conversion of all traditional units employed in engineering, science, and technology to describe forms of energy; gives the energy associated with physical phenomena; and provides energy equivalents of quantities associated with various energy sources. (DT)

  20. CHARMM-GUI Ligand Binder for absolute binding free energy calculations and its application.

    PubMed

    Jo, Sunhwan; Jiang, Wei; Lee, Hui Sun; Roux, Benoît; Im, Wonpil

    2013-01-28

    Advanced free energy perturbation molecular dynamics (FEP/MD) simulation methods are available to accurately calculate absolute binding free energies of protein-ligand complexes. However, these methods rely on several sophisticated command scripts implementing various biasing energy restraints to enhance the convergence of the FEP/MD calculations, which must all be handled properly to yield correct results. Here, we present a user-friendly Web interface, CHARMM-GUI Ligand Binder ( http://www.charmm-gui.org/input/gbinding ), to provide standardized CHARMM input files for calculations of absolute binding free energies using the FEP/MD simulations. A number of features are implemented to conveniently set up the FEP/MD simulations in highly customizable manners, thereby permitting an accelerated throughput of this important class of computations while decreasing the possibility of human errors. The interface and a series of input files generated by the interface are tested with illustrative calculations of absolute binding free energies of three nonpolar aromatic ligands to the L99A mutant of T4 lysozyme and three FK506-related ligands to FKBP12. Statistical errors within individual calculations are found to be small (~1 kcal/mol), and the calculated binding free energies generally agree well with the experimental measurements and the previous computational studies (within ~2 kcal/mol). Therefore, CHARMM-GUI Ligand Binder provides a convenient and reliable way to set up the ligand binding free energy calculations and can be applicable to pharmaceutically important protein-ligand systems.

  1. CHARMM-GUI Ligand Binder for Absolute Binding Free Energy Calculations and Its Application

    PubMed Central

    Jo, Sunhwan; Jiang, Wei; Lee, Hui Sun; Roux, Benoît; Im, Wonpil

    2013-01-01

    Advanced free energy perturbation molecular dynamics (FEP/MD) simulation methods are available to accurately calculate absolute binding free energies of protein-ligand complexes. However, these methods rely on several sophisticated command scripts implementing various biasing energy restraints to enhance the convergence of the FEP/MD calculations, which must all be handled properly to yield correct results. Here, we present a user-friendly web interface, CHARMM-GUI Ligand Binder (http://www.charmm-gui.org/input/gbinding), to provide standardized CHARMM input files for calculations of absolute binding free energies using the FEP/MD simulations. A number of features are implemented to conveniently setup the FEP/MD simulations in highly customizable manners, thereby permitting an accelerated throughput of this important class of computations while decreasing the possibility of human errors. The interface and a series of input files generated by the interface are tested with illustrative calculations of absolute binding free energies of three non-polar aromatic ligands to the L99A mutant of T4 lysozyme and three FK506-related ligands to FKBP12. Statistical errors within individual calculations are found to be small (~1 kcal/mol), and the calculated binding free energies generally agree well with the experimental measurements and the previous computational studies (within ~2 kcal/mol). CHARMM-GUI Ligand Binder provides a convenient and reliable way to setup the ligand binding free energy calculations and can be applicable to pharmaceutically important protein-ligand systems. PMID:23205773

  2. Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 3: Energy conversion subsystems and components. Part 1: Bottoming cycles and materials of construction

    NASA Technical Reports Server (NTRS)

    Shah, R. P.; Solomon, H. D.

    1976-01-01

    Energy conversion subsystems and components were evaluated in terms of advanced energy conversion systems. Results of the bottoming cycles and materials of construction studies are presented and discussed.

  3. Energy Conversion in Photosynthesis: A Paradigm for Solar Fuel Production

    NASA Astrophysics Data System (ADS)

    Moore, Gary F.; Brudvig, Gary W.

    2011-03-01

    Solar energy has the capacity to fulfill global human energy demands in an environmentally and socially responsible manner, provided efficient, low-cost systems can be developed for its capture, conversion, and storage. Toward these ends, a molecular-based understanding of the fundamental principles and mechanistic details of energy conversion in photosynthesis is indispensable. This review addresses aspects of photosynthesis that may prove auspicious to emerging technologies. Conversely, areas in which human ingenuity may offer innovative solutions, resulting in enhanced energy storage efficiencies in artificial photosynthetic constructs, are considered. Emphasis is placed on photoelectrochemical systems that utilize water as a source of electrons for the production of solar fuels.

  4. Plasmon-assisted radiolytic energy conversion in aqueous solutions

    PubMed Central

    Kim, Baek Hyun; Kwon, Jae W.

    2014-01-01

    The field of conventional energy conversion using radioisotopes has almost exclusively focused on solid-state materials. Herein, we demonstrate that liquids can be an excellent media for effective energy conversion from radioisotopes. We also show that free radicals in liquid, which are continuously generated by beta radiation, can be utilized for electrical energy generation. Under beta radiation, surface plasmon obtained by the metallic nanoporous structures on TiO2 enhanced the radiolytic conversion via the efficient energy transfer between plasmons and free radicals. This work introduces a new route for the development of next-generation power sources. PMID:24918356

  5. Demonstrating Energy Conversion with Piezoelectric Crystals and a Paddle Fan

    NASA Astrophysics Data System (ADS)

    Rakbamrung, Prissana; Putson, Chatchai; Muensit, Nantakan

    2014-02-01

    A simple energy conversion system—particularly, the conversion of mechanical energy into electrical energy by using shaker flashlights—has recently been presented. This system uses hand generators, consisting of a magnet in a tube with a coil wrapped around it, and acts as an ac source when the magnet passes back and forth through the coil. Additionally, this system includes an LED, a capacitor, a switch, and a full-wave bridge rectifier. We were inspired by this work to design a simpler demonstrator made for teaching energy conversion concepts to science students using piezoelectric material.

  6. Absolute Binding Free Energy Calculations: On the Accuracy of Computational Scoring of Protein-ligand Interactions

    PubMed Central

    Singh, Nidhi; Warshel, Arieh

    2010-01-01

    Calculating the absolute binding free energies is a challenging task. Reliable estimates of binding free energies should provide a guide for rational drug design. It should also provide us with deeper understanding of the correlation between protein structure and its function. Further applications may include identifying novel molecular scaffolds and optimizing lead compounds in computer-aided drug design. Available options to evaluate the absolute binding free energies range from the rigorous but expensive free energy perturbation to the microscopic Linear Response Approximation (LRA/β version) and its variants including the Linear Interaction Energy (LIE) to the more approximated and considerably faster scaled Protein Dipoles Langevin Dipoles (PDLD/S-LRA version), as well as the less rigorous Molecular Mechanics Poisson–Boltzmann/Surface Area (MM/PBSA) and Generalized Born/Surface Area (MM/GBSA) to the less accurate scoring functions. There is a need for an assessment of the performance of different approaches in terms of computer time and reliability. We present a comparative study of the LRA/β, the LIE, the PDLD/S-LRA/β and the more widely used MM/PBSA and assess their abilities to estimate the absolute binding energies. The LRA and LIE methods perform reasonably well but require specialized parameterization for the non-electrostatic term. On the average, the PDLD/S-LRA/β performs effectively. Our assessment of the MM/PBSA is less optimistic. This approach appears to provide erroneous estimates of the absolute binding energies due to its incorrect entropies and the problematic treatment of electrostatic energies. Overall, the PDLD/S-LRA/β appears to offer an appealing option for the final stages of massive screening approaches. PMID:20186976

  7. Conversion of solar energy to chemical and electrical energy

    SciTech Connect

    Ang, P.; Sammells, A.

    1980-07-29

    A process is described for conversion of solar energy to electrical energy by using a photoelectrochemical membrane cell to regenerate a redox anolyte of a redox-oxygen cell for production of electrical energy. In a photoelectrochemical membrane cell the photosensitizers are illuminated with solar energy thereby producing excited sensitizers and electrons, said sensitizers being located in a redox electrolyte comprising r/o couples adjacent an electron transferring membrane separating said redox electrolyte from a redox aqueous anolyte comprisin a+n/a+n-1 couples, said redox electrolyte couples having a redox potential more negative than the decomposition potential of said sensitizers and said redox anolyte couples having redox potential more positive than the excited state level of the sensitizers or the flat-band potential of a semiconductor sensitizer, passing said electrons through said membrane oxidizing said sensitizers and reducing said redox anolyte couples, regenerating the oxidized sensitizers by reduction in said redox electrolyte producing oxidized redox electrolyte couples, electrochemically regenerating oxidized redox electrolyte couples at the surface of a negative electrode in electronic communication with said redox electroyte and in electronic communication through an external bias circuit with a positive electrode in electronic communication with said redox aqueous anolyte, and venting oxygen produced at said positive electrode. Said reduced redox aqueous anolyte couples are transferred to a redox-oxygen cell. Said reduced redox anolyte couples are passed in contact with a porous flowthrough anode therby oxidizing said couples to a condition suitable for recycle to said photoelectrochemical membrane cell as electron acceptor redox coupl.e

  8. Semiconductor nanowires for photovoltaic and photoelectrochemical energy conversion

    SciTech Connect

    Dasgupta, Neil; Yang, Peidong

    2013-01-23

    Semiconductor nanowires (NW) possess several beneficial properties for efficient conversion of solar energy into electricity and chemical energy. Due to their efficient absorption of light, short distances for minority carriers to travel, high surface-to-volume ratios, and the availability of scalable synthesis methods, they provide a pathway to address the low cost-to-power requirements for wide-scale adaptation of solar energy conversion technologies. Here we highlight recent progress in our group towards implementation of NW components as photovoltaic and photoelectrochemical energy conversion devices. An emphasis is placed on the unique properties of these one-dimensional (1D) structures, which enable the use of abundant, low-cost materials and improved energy conversion efficiency compared to bulk devices.

  9. Self-powered energy fiber: energy conversion in the sheath and storage in the core.

    PubMed

    Yang, Zhibin; Deng, Jue; Sun, Hao; Ren, Jing; Pan, Shaowu; Peng, Huisheng

    2014-11-05

    A high-performance, self-powered, elastic energy fiber is developed that consists of an energy conversion sheath and an energy storage core. The coaxial structure and the aligned nanostructures at the electrode interface enable a high total energy-conversion and energy-storage performance that is maintained under bending and after stretching.

  10. Energy conversion device with support member having pore channels

    DOEpatents

    Routkevitch, Dmitri [Longmont, CO; Wind, Rikard A [Johnstown, CO

    2014-01-07

    Energy devices such as energy conversion devices and energy storage devices and methods for the manufacture of such devices. The devices include a support member having an array of pore channels having a small average pore channel diameter and having a pore channel length. Material layers that may include energy conversion materials and conductive materials are coaxially disposed within the pore channels to form material rods having a relatively small cross-section and a relatively long length. By varying the structure of the materials in the pore channels, various energy devices can be fabricated, such as photovoltaic (PV) devices, radiation detectors, capacitors, batteries and the like.

  11. Space electric power design study. [laser energy conversion

    NASA Technical Reports Server (NTRS)

    Martini, W. R.

    1976-01-01

    The conversion of laser energy to electrical energy is discussed. Heat engines in which the laser heats the gas inside the engine through a window as well as heat engines in which the gas is heated by a thermal energy storage reservoir which has been heated by laser radiation are both evaluated, as well as the necessary energy storage, transmission and conversion components needed for a full system. Preliminary system concepts are presented and a recommended development program is outlined. It appears possible that a free displacer Stirling engine operating directly a linear electric generator can convert 65% of the incident laser energy into electricity.

  12. Tandem filters using frequency selective surfaces for enhanced conversion efficiency in a thermophotovoltaic energy conversion system

    DOEpatents

    Dziendziel, Randolph J.; DePoy, David Moore; Baldasaro, Paul Francis

    2007-01-23

    This invention relates to the field of thermophotovoltaic (TPV) direct energy conversion. In particular, TPV systems use filters to minimize parasitic absorption of below bandgap energy. This invention constitutes a novel combination of front surface filters to increase TPV conversion efficiency by reflecting useless below bandgap energy while transmitting a very high percentage of the useful above bandgap energy. In particular, a frequency selective surface is used in combination with an interference filter. The frequency selective surface provides high transmission of above bandgap energy and high reflection of long wavelength below bandgap energy. The interference filter maintains high transmission of above bandgap energy and provides high reflection of short wavelength below bandgap energy and a sharp transition from high transmission to high reflection.

  13. Tandem filters using frequency selective surfaces for enhanced conversion efficiency in a thermophotovoltaic energy conversion system

    DOEpatents

    Dziendziel, Randolph J.; Baldasaro, Paul F.; DePoy, David M.

    2010-09-07

    This invention relates to the field of thermophotovoltaic (TPV) direct energy conversion. In particular, TPV systems use filters to minimize parasitic absorption of below bandgap energy. This invention constitutes a novel combination of front surface filters to increase TPV conversion efficiency by reflecting useless below bandgap energy while transmitting a very high percentage of the useful above bandgap energy. In particular, a frequency selective surface is used in combination with an interference filter. The frequency selective surface provides high transmission of above bandgap energy and high reflection of long wavelength below bandgap energy. The interference filter maintains high transmission of above bandgap energy and provides high reflection of short wavelength below bandgap energy and a sharp transition from high transmission to high reflection.

  14. Thermophotovoltaic Energy Conversion for Personal Power Sources

    DTIC Science & Technology

    2012-02-01

    solar spectrum, thus the photovoltaic cells used in thermophotovoltaic conversion must be engineered from different material systems. Most common... indium gallium arsenide antimonide (InGaAsSb) on GaSb: 0.53 eV) or indium gallium arsenide (InGaAs) on an indium phosphide (InP) substrate (0.5 to 0.6 eV...The lower bandgap structures are achieved on the InP substrate using InP-based lattice-matched indium gallium arsenide phosphide (InGaAsP) and

  15. Energy dispersive X-ray analysis on an absolute scale in scanning transmission electron microscopy.

    PubMed

    Chen, Z; D'Alfonso, A J; Weyland, M; Taplin, D J; Allen, L J; Findlay, S D

    2015-10-01

    We demonstrate absolute scale agreement between the number of X-ray counts in energy dispersive X-ray spectroscopy using an atomic-scale coherent electron probe and first-principles simulations. Scan-averaged spectra were collected across a range of thicknesses with precisely determined and controlled microscope parameters. Ionization cross-sections were calculated using the quantum excitation of phonons model, incorporating dynamical (multiple) electron scattering, which is seen to be important even for very thin specimens.

  16. Pin stack array for thermoacoustic energy conversion

    DOEpatents

    Keolian, Robert M.; Swift, Gregory W.

    1995-01-01

    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.

  17. Energy balance of wheat conversion to ethanol

    SciTech Connect

    Stumborg, M.A.; Zentner, R.P.; Coxworth, E.

    1996-12-31

    The Western Canadian ethanol industry uses wheat as the preferred feed stock. The net energy balance of an ethanol system based on this starchy feed stock is of interest if Canada utilizes ethanol fuels from wheat as one of its measures to meet international commitments for greenhouse gas reduction and energy conservation under the Green Plan. The wheat to ethanol production systems for the Brown and Thin Black soil zones of the Canadian Prairies were analyzed from soil to processing completion to determine the net energy balance. The data clearly demonstrates the positive net energy balance, with the energy balance ranging from 1.32 to 1.63:1 for the Brown soil zone, and from 1.19 to 1.47:1 for the Thin Black soil zone. The final energy balance depends upon the agronomic practices and wheat variety assumed for the production system.

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

    ERIC Educational Resources Information Center

    Taylor, Beverly A. P.

    1998-01-01

    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)

  19. A summary of USSR thermionic energy conversion activity

    NASA Technical Reports Server (NTRS)

    Rasor, N. S.

    1978-01-01

    The paper surveys the research and development associated with thermionic energy conversion in the USSR. Consideration is given to the basic physics of the thermionic converter, the development of thermionic nuclear reactors including the three TOPAZ models, radioisotope-heated generators, and the thermionic topping of fossil-fueled electric-power plants. Comparisons are made between U.S. and USSR capabilities in thermionic energy conversion and potential cooperative programs are noted.

  20. Status of wind-energy conversion

    NASA Technical Reports Server (NTRS)

    Thomas, R. L.; Savino, J. M.

    1973-01-01

    The utilization of wind energy is technically feasible as evidenced by the many past demonstrations of wind generators. The cost of energy from the wind has been high compared to fossil fuel systems; a sustained development effort is needed to obtain economical systems. The variability of the wind makes it an unreliable source on a short term basis. However, the effects of this variability can be reduced by storage systems or connecting wind generators to: (1) fossil fuel systems; (2) hydroelectric systems; or (3) dispersing them throughout a large grid network. Wind energy appears to have the potential to meet a significant amount of our energy needs.

  1. Energy Conversion and Storage Requirements for Hybrid Electric Aircraft

    NASA Technical Reports Server (NTRS)

    Misra, Ajay

    2016-01-01

    Among various options for reducing greenhouse gases in future large commercial aircraft, hybrid electric option holds significant promise. In the hybrid electric aircraft concept, gas turbine engine is used in combination with an energy storage system to drive the fan that propels the aircraft, with gas turbine engine being used for certain segments of the flight cycle and energy storage system being used for other segments. The paper will provide an overview of various energy conversion and storage options for hybrid electric aircraft. Such options may include fuel cells, batteries, super capacitors, multifunctional structures with energy storage capability, thermoelectric, thermionic or a combination of any of these options. The energy conversion and storage requirements for hybrid electric aircraft will be presented. The role of materials in energy conversion and storage systems for hybrid electric aircraft will be discussed.

  2. Absolute cross-sections for DNA strand breaks and crosslinks induced by low energy electrons.

    PubMed

    Chen, Wenzhuang; Chen, Shiliang; Dong, Yanfang; Cloutier, Pierre; Zheng, Yi; Sanche, Léon

    2016-12-07

    Absolute cross sections (CSs) for the interaction of low energy electrons with condensed macromolecules are essential parameters to accurately model ionizing radiation induced reactions. To determine CSs for various conformational DNA damage induced by 2-20 eV electrons, we investigated the influence of the attenuation length (AL) and penetration factor (f) using a mathematical model. Solid films of supercoiled plasmid DNA with thicknesses of 10, 15 and 20 nm were irradiated with 4.6, 5.6, 9.6 and 14.6 eV electrons. DNA conformational changes were quantified by gel electrophoresis, and the respective yields were extrapolated from exposure-response curves. The absolute CS, AL and f values were generated by applying the model developed by Rezaee et al. The values of AL were found to lie between 11 and 16 nm with the maximum at 14.6 eV. The absolute CSs for the loss of the supercoiled (LS) configuration and production of crosslinks (CL), single strand breaks (SSB) and double strand breaks (DSB) induced by 4.6, 5.6, 9.6 and 14.6 eV electrons are obtained. The CSs for SSB are smaller, but similar to those for LS, indicating that SSB are the main conformational damage. The CSs for DSB and CL are about one order of magnitude smaller than those of LS and SSB. The value of f is found to be independent of electron energy, which allows extending the absolute CSs for these types of damage within the range 2-20 eV, from previous measurements of effective CSs. When comparison is possible, the absolute CSs are found to be in good agreement with those obtained from previous similar studies with double-stranded DNA. The high values of the absolute CSs of 4.6 and 9.6 eV provide quantitative evidence for the high efficiency of low energy electrons to induce DNA damage via the formation of transient anions.

  3. Status of wind-energy conversion

    NASA Technical Reports Server (NTRS)

    Thomas, R. L.; Savino, J. M.

    1973-01-01

    The utilization of wind energy is technically feasible as evidenced by the many past demonstrations of wind generators. The cost of energy from the wind has been high compared to fossil fuel systems. A sustained development effort is needed to obtain economical systems. The variability of the wind makes it an unreliable source on a short-term basis. However, the effects of this variability can be reduced by storage systems or connecting wind generators to fossil fuel systems, hydroelectric systems, or dispersing them throughout a large grid network. The NSF and NASA-Lewis Research Center have sponsored programs for the utilization of wind energy.

  4. Photonic Crystal Emitters for Thermophotovoltaic Energy Conversion

    NASA Astrophysics Data System (ADS)

    Stelmakh, Veronika; Chan, Walker R.; Ghebrebrhan, Michael; Soljacic, Marin; Joannopoulos, John D.; Celanovic, Ivan

    2015-12-01

    This paper reports the design, fabrication, and characterization of 2D photonic crystal (PhC) thermal emitters for a millimeter-scale hydrocarbon TPV microgenerator as a possible replacement for batteries in portable microelectronics, robotics, etc. In our TPV system, combustion heats a PhC emitter to incandescence and the resulting radiation is converted by a low-bandgap TPV cell. The PhC tailors the photonic density of states to produce spectrally confined thermal emission that matches the bandgap of the TPV cell, enabling high heat-to-electricity conversion efficiency. The work builds on a previously developed fabrication process to produce a square array of cylindrical cavities in a metal substrate. We will present ongoing incremental improvements in the optical and thermo-mechanical properties, the fabrication process, and the system integration, as recently combined with fabrication using novel materials, such as sputtered coatings, to enable a monolithic system.

  5. Emerging electrochemical energy conversion and storage technologies

    PubMed Central

    Badwal, Sukhvinder P. S.; Giddey, Sarbjit S.; Munnings, Christopher; Bhatt, Anand I.; Hollenkamp, Anthony F.

    2014-01-01

    Electrochemical cells and systems play a key role in a wide range of industry sectors. These devices are critical enabling technologies for renewable energy; energy management, conservation, and storage; pollution control/monitoring; and greenhouse gas reduction. A large number of electrochemical energy technologies have been developed in the past. These systems continue to be optimized in terms of cost, life time, and performance, leading to their continued expansion into existing and emerging market sectors. The more established technologies such as deep-cycle batteries and sensors are being joined by emerging technologies such as fuel cells, large format lithium-ion batteries, electrochemical reactors; ion transport membranes and supercapacitors. This growing demand (multi billion dollars) for electrochemical energy systems along with the increasing maturity of a number of technologies is having a significant effect on the global research and development effort which is increasing in both in size and depth. A number of new technologies, which will have substantial impact on the environment and the way we produce and utilize energy, are under development. This paper presents an overview of several emerging electrochemical energy technologies along with a discussion some of the key technical challenges. PMID:25309898

  6. Supramolecular Structures for Photochemical Energy Conversion

    SciTech Connect

    Gust, Devens; Moore, Thomas A.; Moore, Ana L.

    2003-08-26

    OAK B188 The goal of this project is to mimic the energy transduction processes by which photosynthetic organisms harvest sunlight and convert it to forms of energy that are more easily used and stored. The results may lead to new technologies for solar energy harvesting based on the natural photosynthetic process. They may also enrich our understanding and control of photosynthesis in living organisms, and lead to methods for increasing natural biomass production, carbon dioxide removal, and oxygen generation. In our work to date, we have learned how to make synthetic antenna and reaction center molecules that absorb light and undergo photoinduced electron transfer to generate long-lived, energetic charge-separated states. We have assembled a prototype system in which artificial reaction centers are inserted into liposomes (artificial cell-like constructs), where they carry out light-driven transmembrane translocation of hydrogen ions to generate proton motive force. By insertion of natural ATP synthase into the liposomal bilayer, this proton motive force has been used to power the synthesis of ATP. ATP is a natural biological energy currency. We are carrying out a systematic investigation of these artificial photosynthetic energy harvesting constructs in order to understand better how they operate. In addition, we are exploring strategies for reversing the direction of the light-powered proton pumping. Most recently, we have extended these studies to develop a light-powered transmembrane calcium ion pump that converts sunlight into energy stored as a calcium ion concentration gradient across a lipid bilayer.

  7. Emerging electrochemical energy conversion and storage technologies.

    PubMed

    Badwal, Sukhvinder P S; Giddey, Sarbjit S; Munnings, Christopher; Bhatt, Anand I; Hollenkamp, Anthony F

    2014-01-01

    Electrochemical cells and systems play a key role in a wide range of industry sectors. These devices are critical enabling technologies for renewable energy; energy management, conservation, and storage; pollution control/monitoring; and greenhouse gas reduction. A large number of electrochemical energy technologies have been developed in the past. These systems continue to be optimized in terms of cost, life time, and performance, leading to their continued expansion into existing and emerging market sectors. The more established technologies such as deep-cycle batteries and sensors are being joined by emerging technologies such as fuel cells, large format lithium-ion batteries, electrochemical reactors; ion transport membranes and supercapacitors. This growing demand (multi billion dollars) for electrochemical energy systems along with the increasing maturity of a number of technologies is having a significant effect on the global research and development effort which is increasing in both in size and depth. A number of new technologies, which will have substantial impact on the environment and the way we produce and utilize energy, are under development. This paper presents an overview of several emerging electrochemical energy technologies along with a discussion some of the key technical challenges.

  8. Improving the Prediction of Absolute Solvation Free Energies Using the Next Generation OPLS Force Field.

    PubMed

    Shivakumar, Devleena; Harder, Edward; Damm, Wolfgang; Friesner, Richard A; Sherman, Woody

    2012-08-14

    Explicit solvent molecular dynamics free energy perturbation simulations were performed to predict absolute solvation free energies of 239 diverse small molecules. We use OPLS2.0, the next generation OPLS force field, and compare the results with popular small molecule force fields-OPLS_2005, GAFF, and CHARMm-MSI. OPLS2.0 produces the best correlation with experimental data (R(2) = 0.95, slope = 0.96) and the lowest average unsigned errors (0.7 kcal/mol). Important classes of compounds that performed suboptimally with OPLS_2005 show significant improvements.

  9. Absolute Helmholtz free energy of highly anharmonic crystals: theory vs Monte Carlo.

    PubMed

    Yakub, Lydia; Yakub, Eugene

    2012-04-14

    We discuss the problem of the quantitative theoretical prediction of the absolute free energy for classical highly anharmonic solids. Helmholtz free energy of the Lennard-Jones (LJ) crystal is calculated accurately while accounting for both the anharmonicity of atomic vibrations and the pair and triple correlations in displacements of the atoms from their lattice sites. The comparison with most precise computer simulation data on sublimation and melting lines revealed that theoretical predictions are in excellent agreement with Monte Carlo simulation data in the whole range of temperatures and densities studied.

  10. Energy Conversion and Storage Program: 1992 Annual report

    SciTech Connect

    Cairns, E.J.

    1993-06-01

    This report is the 1992 annual progress report for the Energy Conversion and Storage Program, a part of the Energy and Environment Division of the Lawrence Berkeley Laboratory. Work described falls into three broad areas: electrochemistry; chemical applications; and materials applications. The Energy Conversion and Storage Program applies principles of chemistry and materials science to solve problems in several areas: (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 chemical species, and (5) study and 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. 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 product and waste streams from synfuel plants, coal gasifiers, and biomass conversion processes. Materials applications research includes evaluation of the properties of advanced materials, as well as development of novel preparation techniques. For example, techniques such as sputtering, laser ablation, and poised laser deposition are being used to produce high-temperature superconducting films.

  11. Advanced Energy Conversion System Using Sinusoidal Voltage Tracking Buck-Boost Converter Cascaded Polarity Changing Inverter

    NASA Astrophysics Data System (ADS)

    Ahmed, Nabil A.

    2011-06-01

    This paper presents an advanced power converter employs a sinusoidal voltage absolute value tracking buck-boost DC-DC converter in the first power processing stage and a polarity changing full-bridge inverter in the second stage. The proposed power conversion system has the capability of delivering sinusoidal output and input current with unity power factor and good output voltage regulation. Consequently, the complete voltage regulator system, which is mainly suitable for new energy generation systems as well as energy storage systems, can be constructed compactly and inexpensively without DC link electrolytic capacitor. Also, the paper presents an auxiliary passive resonant circuit for soft switching operation. Simulation results using PSIM software are presented to verify the operation principles and feasibility of the proposed power conversion system.

  12. Absolute pulse energy measurements of soft x-rays at the Linac Coherent Light Source.

    PubMed

    Tiedtke, K; Sorokin, A A; Jastrow, U; Juranić, P; Kreis, S; Gerken, N; Richter, M; Arp, U; Feng, Y; Nordlund, D; Soufli, R; Fernández-Perea, M; Juha, L; Heimann, P; Nagler, B; Lee, H J; Mack, S; Cammarata, M; Krupin, O; Messerschmidt, M; Holmes, M; Rowen, M; Schlotter, W; Moeller, S; Turner, J J

    2014-09-08

    This paper reports novel measurements of x-ray optical radiation on an absolute scale from the intense and ultra-short radiation generated in the soft x-ray regime of a free electron laser. We give a brief description of the detection principle for radiation measurements which was specifically adapted for this photon energy range. We present data characterizing the soft x-ray instrument at the Linac Coherent Light Source (LCLS) with respect to the radiant power output and transmission by using an absolute detector temporarily placed at the downstream end of the instrument. This provides an estimation of the reflectivity of all x-ray optical elements in the beamline and provides the absolute photon number per bandwidth per pulse. This parameter is important for many experiments that need to understand the trade-offs between high energy resolution and high flux, such as experiments focused on studying materials via resonant processes. Furthermore, the results are compared with the LCLS diagnostic gas detectors to test the limits of linearity, and observations are reported on radiation contamination from spontaneous undulator radiation and higher harmonic content.

  13. Advanced Thermal Energy Conversion of Temperature under 300°C by Thermoelectric Conversion Method

    NASA Astrophysics Data System (ADS)

    Ueda, Tadashi; Uchida, Yoshiyuki; Shingu, Hiroyasu

    Many approaches have been developing for energy conversion throughout the world. However, it is difficult to achieve the global warming countermeasure based on “The Kyoto protocol”. Until now effective utilization of low temperature thermal energy (under 300°C) is not advancing one. For example, effective utilization method has not been established for waste heat energy which arise from industry machine tools, automobiles, internal combustion engines and thermal energy from natural environment, etc. In this paper, we reported the experiment for effective utilizing of low temperature (under 300°C) thermal energy conversion. The device used for the measurement is a copper thermo device. Thermo electromotive force of 150mW/cm2 was obtained at 200°C. The obtained thermo electromotive force is about 15 times higher in comparison with generally used alumal-chromal thermocouple. Our aim is that utilizes low temperature thermal energy effectively by converting into electricity.

  14. Low to high temperature energy conversion system

    NASA Technical Reports Server (NTRS)

    Miller, C. G. (Inventor)

    1977-01-01

    A method for converting heat energy from low temperature heat sources to higher temperature was developed. It consists of a decomposition chamber in which ammonia is decomposed into hydrogen and nitrogen by absorbing heat of decomposition from a low temperature energy source. A recombination reaction then takes place which increases the temperature of a fluid significantly. The system is of use for the efficient operation of compact or low capital investment turbine driven electrical generators, or in other applications, to enable chemical reactions that have a critical lower temperature to be used. The system also recovers heat energy from low temperature heat sources, such as solar collectors or geothermal sources, and converts it to high temperatures.

  15. Physical Limits of Solar Energy Conversion in the Earth System.

    PubMed

    Kleidon, Axel; Miller, Lee; Gans, Fabian

    2016-01-01

    Solar energy provides by far the greatest potential for energy generation among all forms of renewable energy. Yet, just as for any form of energy conversion, it is subject to physical limits. Here we review the physical limits that determine how much energy can potentially be generated out of sunlight using a combination of thermodynamics and observed climatic variables. We first explain how the first and second law of thermodynamics constrain energy conversions and thereby the generation of renewable energy, and how this applies to the conversions of solar radiation within the Earth system. These limits are applied to the conversion of direct and diffuse solar radiation - which relates to concentrated solar power (CSP) and photovoltaic (PV) technologies as well as biomass production or any other photochemical conversion - as well as solar radiative heating, which generates atmospheric motion and thus relates to wind power technologies. When these conversion limits are applied to observed data sets of solar radiation at the land surface, it is estimated that direct concentrated solar power has a potential on land of up to 11.6 PW (1 PW=10(15) W), whereas photovoltaic power has a potential of up to 16.3 PW. Both biomass and wind power operate at much lower efficiencies, so their potentials of about 0.3 and 0.1 PW are much lower. These estimates are considerably lower than the incoming flux of solar radiation of 175 PW. When compared to a 2012 primary energy demand of 17 TW, the most direct uses of solar radiation, e.g., by CSP or PV, have thus by far the greatest potential to yield renewable energy requiring the least space to satisfy the human energy demand. Further conversions into solar-based fuels would be reduced by further losses which would lower these potentials. The substantially greater potential of solar-based renewable energy compared to other forms of renewable energy simply reflects much fewer and lower unavoidable conversion losses when solar

  16. Porous media for catalytic renewable energy conversion

    NASA Astrophysics Data System (ADS)

    Hotz, Nico

    2012-05-01

    A novel flow-based method is presented to place catalytic nanoparticles into a reactor by sol-gelation of a porous ceramic consisting of copper-based nanoparticles, silica sand, ceramic binder, and a gelation agent. This method allows for the placement of a liquid precursor containing the catalyst into the final reactor geometry without the need of impregnating or coating of a substrate with the catalytic material. The so generated foam-like porous ceramic shows properties highly appropriate for use as catalytic reactor material, e.g., reasonable pressure drop due to its porosity, high thermal and catalytic stability, and excellent catalytic behavior. The catalytic activity of micro-reactors containing this foam-like ceramic is tested in terms of their ability to convert alcoholic biofuel (e.g. methanol) to a hydrogen-rich gas mixture with low concentrations of carbon monoxide (up to 75% hydrogen content and less than 0.2% CO, for the case of methanol). This gas mixture is subsequently used in a low-temperature fuel cell, converting the hydrogen directly to electricity. A low concentration of CO is crucial to avoid poisoning of the fuel cell catalyst. Since conventional Polymer Electrolyte Membrane (PEM) fuel cells require CO concentrations far below 100 ppm and since most methods to reduce the mole fraction of CO (such as Preferential Oxidation or PROX) have CO conversions of up to 99%, the alcohol fuel reformer has to achieve initial CO mole fractions significantly below 1%. The catalyst and the porous ceramic reactor of the present study can successfully fulfill this requirement.

  17. Preliminary results on the conversion of laser energy into electricity

    NASA Technical Reports Server (NTRS)

    Thompson, R. W.; Manista, E. J.; Alger, D. L.

    1978-01-01

    A preliminary experiment was performed to investigate conversion of 10.6 micron laser energy to electrical energy via a laser-sustained argon plasma. Short-circuit currents of 0.7 A were measured between a thoriated-tungsten emitter and collector electrodes immersed in the laser-sustained argon plasma. Open-circuit voltages of about 1.5 V were inferred from the current-voltage load characteristics. The dominant mechanism of laser energy conversion is uncertain at this time. Much higher output powers appear possible.

  18. Cogeneration Technology Alternatives Study (CTAS). Volume 4: Energy conversion systems

    NASA Technical Reports Server (NTRS)

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

    1980-01-01

    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 considered included food, textiles, lumber, paper, chemicals, petroleum, glass, and primary metals. The energy conversion systems included steam and gas turbines, diesels, thermionics, stirling, closed-cycle and steam injected gas turbines, and fuel cells. Fuels considered were coal, both coal and petroleum-based residual and distillate liquid fuels, and low Btu gas obtained through the on-site gasification of coal. An attempt was made to use consistent assumptions and a consistent set of ground rules specified by NASA for determining performance and cost. The advanced and commercially available cogeneration energy conversion systems studied in CTAS are fined together with their performance, capital costs, and the research and developments required to bring them to this level of performance.

  19. Cogeneration Technology Alternatives Study (CTAS). Volume 4: Energy conversion systems

    NASA Astrophysics Data System (ADS)

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

    1980-04-01

    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 considered included food, textiles, lumber, paper, chemicals, petroleum, glass, and primary metals. The energy conversion systems included steam and gas turbines, diesels, thermionics, stirling, closed-cycle and steam injected gas turbines, and fuel cells. Fuels considered were coal, both coal and petroleum-based residual and distillate liquid fuels, and low Btu gas obtained through the on-site gasification of coal. An attempt was made to use consistent assumptions and a consistent set of ground rules specified by NASA for determining performance and cost. The advanced and commercially available cogeneration energy conversion systems studied in CTAS are fined together with their performance, capital costs, and the research and developments required to bring them to this level of performance.

  20. Wind Energy Conversion Systems. A Unit of Instruction.

    ERIC Educational Resources Information Center

    Greenwald, Martin

    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…

  1. Ocean thermal energy conversion: report to congress - fiscal year 1982

    SciTech Connect

    Not Available

    1983-03-31

    National Oceanic and Atmospheric Administration (NOAA) activities related to ocean thermal energy conversion (OTEC) during fiscal year 1982 are described. The agency focus has been in the areas of providing ocean engineering and technical assistance to the Department of Energy (DOE), in streamlining the administration of the Federal OTEC licensing system, and in environmental assistance.

  2. Alcan's ocean thermal energy conversion (OTEC) program

    SciTech Connect

    Hron, V.; Fitzpatrick, N.P. ); Hay, E. ); Johnson, F.A. )

    1991-01-01

    Since 1985 Alcan has been operating equipment at a test site at the National Energy Laboratory of Hawaii at Keahole Point near Kona in Hawaii. Segments of aluminum heat exchangers are exposed to surface sea water at 27{degrees} C and to water from 2000 ft down coming in at 7{degrees} C. Progress was such that in 1988 Alcan contracted GEC to design a 250 kW pilot facility. The cold deep water, suitable for air conditioning, is rich in nutrients and the hierarchy of mariculture products one might select is outlined. This paper reports that closed-cycle OTEC may be economical, practical and capable of having a significant impact upon world energy needs. It can be implemented on a small scale using revenues derived from fresh water production and mariculture.

  3. Integrated devices to realize energy conversion and storage simultaneously.

    PubMed

    Chen, Tao; Yang, Zhibin; Peng, Huisheng

    2013-06-24

    Other forms of energy are generally converted to electric energy and then transported to electrochemical devices, where the energy is stored, by external electric wires. To further improve total energy conversion and storage efficiency, interest in simultaneously realize the energy conversion and storage in a single device has increased. This Concept describes recent progress in developing such novel integrated energy devices. Both planar and wire architectures are carefully illustrated with an emphasis on the "energy wire" which has been the focus of past developments due to its unique and promising applications, such as being woven into clothes or other complex structures by conventional textile technology. The current challenges and future directions of the integrated devices, particularly in the wire architecture, are summarized.

  4. Photovoltaic and photoelectrochemical conversion of solar energy.

    PubMed

    Grätzel, Michael

    2007-04-15

    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.

  5. Massively parallel computation of absolute binding free energy with well-equilibrated states

    NASA Astrophysics Data System (ADS)

    Fujitani, Hideaki; Tanida, Yoshiaki; Matsuura, Azuma

    2009-02-01

    A force field formulator for organic molecules (FF-FOM) was developed to assign bond, angle, and dihedral parameters to arbitrary organic molecules in a unified manner including proteins and nucleic acids. With the unified force field parametrization we performed massively parallel computations of absolute binding free energies for pharmaceutical target proteins and ligands. Compared with the previous calculation with the ff99 force field in the Amber simulation package (Amber99) and the ligand charges produced by the Austin Model 1 bond charge correction (AM1-BCC), the unified parametrization gave better absolute binding energies for the FK506 binding protein (FKBP) and ligand system. Our method is based on extensive work measurement between thermodynamic states to calculate the free energy difference and it is also the same as the traditional free energy perturbation. There are important requirements for accurate calculations. The first is a well-equilibrated bound structure including the conformational change of the protein induced by the binding of the ligand. The second requirement is the convergence of the work distribution with a sufficient number of trajectories and dense spacing of the coupling constant between the ligand and the rest of the system. Finally, the most important requirement is the force field parametrization.

  6. Energy: A continuing bibliography with indexes, February 1975. [solar energy, energy conversion

    NASA Technical Reports Server (NTRS)

    1975-01-01

    Reports, articles, and other documents introduced into the NASA scientific and technical information system from July 1, 1974 through September 30, 1974 are cited. Regional, national, and international energy systems; research and development on fuels and other sources of energy; energy conversion, transport, transmission, distribution, and storage, with emphasis on the use of hydrogen and solar energy are included along with methods of locating or using new energy resources. Emphasis is placed on energy for heating, lighting, and powering aircraft, surface vehicles, or other machinery.

  7. Chemoelectrical energy conversion of adenosine triphosphate

    NASA Astrophysics Data System (ADS)

    Sundaresan, Vishnu Baba; Sarles, Stephen Andrew; Leo, Donald J.

    2007-04-01

    Plant and animal cell membranes transport charged species, neutral molecules and water through ion pumps and channels. The energy required for moving species against established concentration and charge gradients is provided by the biological fuel - adenosine triphosphate (ATP) -synthesized within the cell. The adenosine triphosphatase (ATPases) in a plant cell membrane hydrolyze ATP in the cell cytoplasm to pump protons across the cell membrane. This establishes a proton gradient across the membrane from the cell exterior into the cell cytoplasm. This proton motive force stimulates ion channels that transport nutrients and other species into the cell. This article discusses a device that converts the chemical energy stored in adenosine triphosphate into electrical power using a transporter protein, ATPase. The V-type ATPase proteins used in our prototype are extracted from red beet(Beta vulgaris) tonoplast membranes and reconstituted in a bilayer lipid membrane or BLM formed from POPC and POPS lipids. A pH7 medium that can support ATP hydrolysis is provided on both sides of the membrane and ATP is dissolved in the pH7 buffer on one side of the membrane. Hydrolysis of ATP results in the formation of a phosphate ion and adenosine diphosphate. The energy from the reaction activates ATPase in the BLM and moves a proton across the membrane. The charge gradient established across the BLM due to the reaction and ion transport is converted into electrical current by half-cell reference electrodes. The prototype ATPase cell with an effective BLM area of 4.15 mm2 carrying 15 μl of ATPase proteins was observed to develop a steady state peak power output of 70 nW, which corresponds to a specific power of 1.69 μW/cm2 and a current density of 43.4 μA/cm2 of membrane area.

  8. Energy Conversion and Storage Program. 1990 annual report

    SciTech Connect

    Cairns, E.J.

    1992-03-01

    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.

  9. Optimizing Energy Conversion: Magnetic Nano-materials

    NASA Astrophysics Data System (ADS)

    McIntyre, Dylan; Dann, Martin; Ilie, Carolina C.

    2015-03-01

    We present herein the work started at SUNY Oswego as a part of a SUNY 4E grant. The SUNY 4E Network of Excellence has awarded SUNY Oswego and collaborators a grant to carry out extensive studies on magnetic nanoparticles. The focus of the study is to develop cost effective rare-earth-free magnetic materials that will enhance energy transmission performance of various electrical devices (solar cells, electric cars, hard drives, etc.). The SUNY Oswego team has started the preliminary work for the project and graduate students from the rest of the SUNY 4E team (UB, Alfred College, Albany) will continue the project. The preliminary work concentrates on analyzing the properties of magnetic nanoparticle candidates, calculating molecular orbitals and band gap, and the fabrication of thin films. SUNY 4E Network of Excellence Grant.

  10. Absolute polarimeter for the proton-beam energy of 200 MeV

    SciTech Connect

    Zelenski, A. N.; Atoian, G.; Bogdanov, A. A.; Nurushev, S. B.; Pylaev, F. S.; Raparia, D.; Runtso, M. F.; Stephenson, E.

    2013-12-15

    A polarimeter is upgraded and tested in a 200-MeV polarized-proton beam at the accelerator-collider facility of the Brookhaven National Laboratory. The polarimeter is based on the elastic polarizedproton scattering on a carbon target at an angle of 16.2°, in which case the analyzing power is close to unity and was measured to a very high degree of precision. It is shown that, in the energy range of 190–205 MeV, the absolute polarization can be measured to a precision better than ±0.5%.

  11. Measurement of the lithium 10p fine structure interval and absolute energy

    SciTech Connect

    Oxley, Paul; Collins, Patrick

    2010-02-15

    We report a measurement of the fine structure interval of the {sup 7}Li 10p atomic state with a precision significantly better than previous measurements of fine structure intervals of Rydberg {sup 7}Li p states. Our result of 74.97(74) MHz provides an experimental value for the only n=10 fine structure interval which is yet to be calculated. We also report a measurement of the absolute energy of the 10p state and its quantum defect, which are, respectively, 42379.498(23)cm{sup -1} and 0.04694(10). These results are in good agreement with recent calculations.

  12. Functionalization of graphene for efficient energy conversion and storage.

    PubMed

    Dai, Liming

    2013-01-15

    As global energy consumption accelerates at an alarming rate, the development of clean and renewable energy conversion and storage systems has become more important than ever. Although the efficiency of energy conversion and storage devices depends on a variety of factors, their overall performance strongly relies on the structure and properties of the component materials. 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. As a building block for carbon materials of all other dimensionalities (such as 0D buckyball, 1D nanotube, 3D graphite), the two-dimensional (2D) single atomic carbon sheet of graphene has emerged as an attractive candidate for energy applications due to its unique structure and properties. Like other materials, however, a graphene-based material that possesses desirable bulk properties rarely features the surface characteristics required for certain specific applications. Therefore, surface functionalization is essential, and researchers have devised various covalent and noncovalent chemistries for making graphene materials with the bulk and surface properties needed for efficient energy conversion and storage. In this Account, I summarize some of our new ideas and strategies for the controlled functionalization of graphene for the development of efficient energy conversion and storage devices, such as solar cells, fuel cells, supercapacitors, and batteries. The dangling bonds at the edge of graphene can be used for the covalent attachment of various chemical moieties while the graphene basal plane can be modified via either covalent or noncovalent functionalization. The asymmetric functionalization of the two opposite surfaces of individual graphene sheets with different moieties can lead to the self-assembly of graphene sheets into hierarchically structured materials. Judicious

  13. SOLID STATE ENERGY CONVERSION ALLIANCE DELPHI SOFC

    SciTech Connect

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

    2003-06-09

    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.

  14. Ocean thermal energy conversion: a review

    SciTech Connect

    Yuen, P.C.

    1981-10-01

    The OTEC principle is discussed along with general system and cycle types, specific OTEC designs, OTEC applications, and the ocean thermal resource. The historic development of OTEC is briefly reviewed, and the status of French, Japanese, EUROCEAN, and US programs is assessed. US efforts are detailed and DOE's strategy outlined with OTEC-1 and Mini-OTEC information. Power system components of the more technically advanced closed-cycle OTEC concept are discussed. These include: heat exchangers, corrosion and biofouling countermeasures, working fluids, ammonia power systems, and on-platform seawater systems. Several open-cycle features are also discussed. A critical review is presented of the ocean engineering aspects of OTEC power systems. Major subsystems such as platform, cold water pipe, mooring system, dynamic positioning system, power transmission cable system are assessed for their relationships with the ocean environment and with each other. Nine available studies of OTEC costs are reviewed. Tentative comparisons are made between OTEC and traditional fuel costs, and OTEC products and markets are considered. Possible environmental and social effects of OTEC development are discussed. International, national, and local laws regulating OTEC plants and OTEC energy products are reviewed. Tax incentives, attitudes of the utilities, and additional legislative needs are considered. (LEW)

  15. Ocean Thermal Energy Conversion Program Management Plan

    SciTech Connect

    Combs, R E

    1980-01-01

    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 support to CORO in its capacity as manager of the DOE power-system program. The Argonne OTEC Program is divided into three components: the first deals with development of heat exchangers and other components of OTEC power systems, the second with development of biofouling counter-measures and corrosion-resistant materials for these components in seawater service, and the third with environmental and climatic impacts of OTEC power-system operation. The essential points of the Management Plan are summarized, and the OTEC Program is described. The organization of the OTEC Program at ANL is described including the functions, responsibilities, and authorities of the organizational groupings. The system and policies necessary for the support and control functions within the organization are discussed. These functions cross organizational lines, in that they are common to all of the organization groups. Also included are requirements for internal and external reports.

  16. Measurement procedure for absolute broadband infrared up-conversion photoluminescent quantum yields: Correcting for absorption/re-emission

    SciTech Connect

    MacDougall, Sean K. W.; Ivaturi, Aruna; Marques-Hueso, Jose; Richards, Bryce S.

    2014-06-15

    The internal photoluminescent quantum yield (iPLQY) – defined as the ratio of emitted photons to those absorbed – is an important parameter in the evaluation and application of luminescent materials. The iPLQY is rarely reported due to the complexities in the calibration of such a measurement. Herein, an experimental method is proposed to correct for re-emission, which leads to an underestimation of the absorption under broadband excitation. Although traditionally the iPLQY is measured using monochromatic sources for linear materials, this advancement is necessary for nonlinear materials with wavelength dependent iPLQY, such as the application of up-conversion to solar energy harvesting. The method requires an additional measurement of the emission line shape that overlaps with the excitation and absorption spectra. Through scaling of the emission spectrum, at the long wavelength edge where an overlap of excitation does not occur, it is possible to better estimate the value of iPLQY. The method has been evaluated for a range of nonlinear material concentrations and under various irradiances to analyze the necessity and boundary conditions that favor the proposed method. Use of this refined method is important for a reliable measurement of iPLQY under a broad illumination source such as the Sun.

  17. Prediction of Absolute Solvation Free Energies using Molecular Dynamics Free Energy Perturbation and the OPLS Force Field.

    PubMed

    Shivakumar, Devleena; Williams, Joshua; Wu, Yujie; Damm, Wolfgang; Shelley, John; Sherman, Woody

    2010-05-11

    The accurate prediction of protein-ligand binding free energies is a primary objective in computer-aided drug design. The solvation free energy of a small molecule provides a surrogate to the desolvation of the ligand in the thermodynamic process of protein-ligand binding. Here, we use explicit solvent molecular dynamics free energy perturbation to predict the absolute solvation free energies of a set of 239 small molecules, spanning diverse chemical functional groups commonly found in drugs and drug-like molecules. We also compare the performance of absolute solvation free energies obtained using the OPLS_2005 force field with two other commonly used small molecule force fields-general AMBER force field (GAFF) with AM1-BCC charges and CHARMm-MSI with CHelpG charges. Using the OPLS_2005 force field, we obtain high correlation with experimental solvation free energies (R(2) = 0.94) and low average unsigned errors for a majority of the functional groups compared to AM1-BCC/GAFF or CHelpG/CHARMm-MSI. However, OPLS_2005 has errors of over 1.3 kcal/mol for certain classes of polar compounds. We show that predictions on these compound classes can be improved by using a semiempirical charge assignment method with an implicit bond charge correction.

  18. Photoassisted electrolysis of water - Conversion of optical to chemical energy

    NASA Technical Reports Server (NTRS)

    Wrighton, M. S.; Bolts, J. M.; Kaiser, S. W.; Ellis, A. B.

    1976-01-01

    A description is given of devices, termed photoelectrochemical cells, which can, in principle, be used to directly convert light to fuels and/or electricity. The fundamental principles on which the photoelectrochemical cell is based are related to the observation that irradiation of a semiconductor electrode in an electrochemical cell can result in the flow of an electric current in the external circuit. Attention is given to the basic mechanisms involved, the energy conversion efficiency, the advantages of photoelectrochemical cells, and the results of investigations related to the study of energy conversion via photoelectrochemical cells.

  19. Nanogold plasmonic photocatalysis for organic synthesis and clean energy conversion.

    PubMed

    Wang, Changlong; Astruc, Didier

    2014-01-01

    This review provides the basic concepts, an overall survey and the state-of-the art of plasmon-based nanogold photocatalysis using visible light including fundamental understanding and major applications to organic reactions and clean energy-conversion systems. First, the basic concepts of localized surface plasmon resonance (LSPR) are recalled, then the major preparation methods of AuNP-based plasmonic photocatalysts are reviewed. The major part of the review is dedicated to the latest progress in the application of nanogold plasmonic photocatalysis to organic transformations and energy conversions, and the proposed mechanisms are discussed. In conclusion, new challenges and perspectives are proposed and analyzed.

  20. Nanofluidic sustainable energy conversion using a 1D nanofluidic network.

    PubMed

    Kim, Sang Hui; Kwak, Seungmin; Han, Sung Il; Chun, Dong Won; Lee, Kyu Hyoung; Kim, Jinseok; Lee, Jeong Hoon

    2014-05-01

    We propose a 1-dimensional (1D) nanofluidic energy conversion device by implementing a surface-patterned Nafion membrane for the direct energy conversion of the pressure to electrical power. By implementing a -200-nm-thick nano-bridge with a 5-nm pore size between two microfluidic channels, we acquired an effective streaming potential of 307 mV and output power of 94 pW with 0.1 mM KCI under pressure difference of 45 MPa. The experimental results show both the effects of applied pressure differences and buffer concentrations on the effective streaming potential, and are consistent with the analytical prediction.

  1. The sarcomeric control of energy conversion.

    PubMed

    Levy, Carmit; Ter Keurs, Henk E D J; Yaniv, Yael; Landesberg, Amir

    2005-06-01

    The Frank-Starling Law, Fenn Effect, and Suga's suggestions of cardiac muscle constant contractile efficiency establish the dependence of cardiac mechanics and energetics on the loading conditions. Consistent with these observations, this review suggests that the sarcomere control of contraction consists of two dominant feedbacks: (1) a cooperativity mechanism (positive feedback), whereby the number of force-generating cross-bridges (XBs) determines the affinity of calcium binding to the troponin regulatory protein; and (2) a mechanical (negative) feedback, whereby the filament shortening velocity affects the rate of XB turnover from the force to the non-force generating conformation. The study explains the roles of these feedbacks in providing the adaptive control of energy consumption by the loading conditions and validates the dependence of the cooperativity mechanism on the number of strong XBs. The cooperativity mechanism regulates XB recruitment. It explains the cardiac force-length calcium relationship, the related Frank-Starling Law of the heart, and the adaptive control of new XB recruitment and the associated adenosine triphosphate (ATP) consumption. The mechanical feedback explains the force-velocity relationship and the constant and high-contractile efficiency. These mechanisms were validated by testing the force responses to large amplitude (100 nm/sarcomere) sarcomere length (SL) oscillations, in intact tetanized trabeculae (utilizing 30 microM cyclopiazonic). The force responses to large-length oscillations lag behind the imposed oscillations at low extracellular calcium concentration ([Ca(2+)](0)) and slow frequencies (<4 Hz, 25 degrees C), yielding counterclockwise hystereses in the force-length plane. The force was higher during shortening than during lengthening. The area within these hystereses corresponds to the external work generated from new XB recruitment during each oscillation, and it is determined by the delay in the force response

  2. Direct energy conversion system for D(3)-He fusion

    NASA Astrophysics Data System (ADS)

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

    1993-11-01

    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 line-cusp and the energy of thermal ion components is converted at the second cusp DEC. The fusion protons go through the cusp-type DEC and arrive at the TWDEC, which principle is similar to 'LINAC'. The energy of fusion protons is recovered to electricity with an efficiency of more than 70%. These DEC's bring about the high efficient fusion plant.

  3. Mesoporous materials for energy conversion and storage devices

    NASA Astrophysics Data System (ADS)

    Li, Wei; Liu, Jun; Zhao, Dongyuan

    2016-06-01

    To meet the growing energy demands in a low-carbon economy, the development of new materials that improve the efficiency of energy conversion and storage systems is essential. Mesoporous materials offer opportunities in energy conversion and storage applications owing to their extraordinarily high surface areas and large pore volumes. These properties may improve the performance of materials in terms of energy and power density, lifetime and stability. In this Review, we summarize the primary methods for preparing mesoporous materials and discuss their applications as electrodes and/or catalysts in solar cells, solar fuel production, rechargeable batteries, supercapacitors and fuel cells. Finally, we outline the research and development challenges of mesoporous materials that need to be overcome to increase their contribution in renewable energy applications.

  4. Efficient electrochemical CO2 conversion powered by renewable energy.

    PubMed

    Kauffman, Douglas R; Thakkar, Jay; Siva, Rajan; Matranga, Christopher; Ohodnicki, Paul R; Zeng, Chenjie; Jin, Rongchao

    2015-07-22

    The catalytic conversion of CO2 into industrially relevant chemicals is one strategy for mitigating greenhouse gas emissions. Along these lines, electrochemical CO2 conversion technologies are attractive because they can operate with high reaction rates at ambient conditions. However, electrochemical systems require electricity, and CO2 conversion processes must integrate with carbon-free, renewable-energy sources to be viable on larger scales. We utilize Au25 nanoclusters as renewably powered CO2 conversion electrocatalysts with CO2 → CO reaction rates between 400 and 800 L of CO2 per gram of catalytic metal per hour and product selectivities between 80 and 95%. These performance metrics correspond to conversion rates approaching 0.8-1.6 kg of CO2 per gram of catalytic metal per hour. We also present data showing CO2 conversion rates and product selectivity strongly depend on catalyst loading. Optimized systems demonstrate stable operation and reaction turnover numbers (TONs) approaching 6 × 10(6) molCO2 molcatalyst(-1) during a multiday (36 h total hours) CO2 electrolysis experiment containing multiple start/stop cycles. TONs between 1 × 10(6) and 4 × 10(6) molCO2 molcatalyst(-1) were obtained when our system was powered by consumer-grade renewable-energy sources. Daytime photovoltaic-powered CO2 conversion was demonstrated for 12 h and we mimicked low-light or nighttime operation for 24 h with a solar-rechargeable battery. This proof-of-principle study provides some of the initial performance data necessary for assessing the scalability and technical viability of electrochemical CO2 conversion technologies. Specifically, we show the following: (1) all electrochemical CO2 conversion systems will produce a net increase in CO2 emissions if they do not integrate with renewable-energy sources, (2) catalyst loading vs activity trends can be used to tune process rates and product distributions, and (3) state-of-the-art renewable-energy technologies are sufficient

  5. Efficient electrochemical CO2 conversion powered by renewable energy

    DOE PAGES

    Kauffman, Douglas R.; Thakkar, Jay; Siva, Rajan; ...

    2015-06-29

    Here, the catalytic conversion of CO2 into industrially relevant chemicals is one strategy for mitigating greenhouse gas emissions. Along these lines, electrochemical CO2 conversion technologies are attractive because they can operate with high reaction rates at ambient conditions. However, electrochemical systems require electricity, and CO2 conversion processes must integrate with carbon-free, renewable-energy sources to be viable on larger scales. We utilize Au25 nanoclusters as renewably powered CO2 conversion electrocatalysts with CO2 → CO reaction rates between 400 and 800 L of CO2 per gram of catalytic metal per hour and product selectivities between 80 and 95%. These performance metrics correspondmore » to conversion rates approaching 0.8–1.6 kg of CO2 per gram of catalytic metal per hour. We also present data showing CO2 conversion rates and product selectivity strongly depend on catalyst loading. Optimized systems demonstrate stable operation and reaction turnover numbers (TONs) approaching 6 × 106 mol CO2 molcatalyst–1 during a multiday (36 hours total hours) CO2electrolysis experiment containing multiple start/stop cycles. TONs between 1 × 106 and 4 × 106 molCO2 molcatalyst–1 were obtained when our system was powered by consumer-grade renewable-energy sources. Daytime photovoltaic-powered CO2 conversion was demonstrated for 12 h and we mimicked low-light or nighttime operation for 24 h with a solar-rechargeable battery. This proof-of-principle study provides some of the initial performance data necessary for assessing the scalability and technical viability of electrochemical CO2 conversion technologies. Specifically, we show the following: (1) all electrochemical CO2 conversion systems will produce a net increase in CO2 emissions if they do not integrate with renewable-energy sources, (2) catalyst loading vs activity trends can be used to tune process rates and product distributions, and (3) state-of-the-art renewable-energy technologies

  6. ABSOLUTE MEASUREMENT OF THE POLARIZATION OF HIGH ENERGY PROTON BEAMS AT RHIC

    SciTech Connect

    MAKDISI,Y.; BRAVAR, A. BUNCE, G. GILL, R.; HUANG, H.; ET AL.

    2007-06-25

    The spin physics program at the Relativistic Heavy Ion Collider (RHIC) requires knowledge of the beam polarization to better than 5%. Such a goal is made the more difficult by the lack of knowledge of the analyzing power of high energy nuclear physics processes. To overcome this, a polarized hydrogen jet target was constructed and installed at one intersection region in RHIC where it intersects both beams and utilizes the precise knowledge of the jet atomic hydrogen beam polarization to measure the analyzing power in proton-proton elastic scattering in the Nuclear Coulomb Interference (CNI) region at the prescribed RHIC proton beam energy. The reverse reaction is used to assess the absolute beam polarization. Simultaneous measurements taken with fast high statistics polarimeters that measure the p-Carbon elastic scattering process also in the CNI region use the jet results to calibrate the latter.

  7. Proceedings of the 25th intersociety energy conversion engineering conference

    SciTech Connect

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

    1990-01-01

    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.

  8. The NASA program in Space Energy Conversion Research and Technology

    NASA Technical Reports Server (NTRS)

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

    1982-01-01

    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.

  9. Energy conversion via ferroic materials: Materials, mechanisms, and applications

    NASA Astrophysics Data System (ADS)

    Chin, Huai-An

    Energy conversion is a process converting one form of energy into another. Significant research effort has been dedicated to energy conversion mechanisms for portable energy conversion. Specifically, mechanisms based on ferroic materials have been widely explored for this goal. Ferroic materials include ferromagnetic, ferroelectric and ferroelastic materials. This thesis is focused on two ferroic materials: ferromagnetic TbxDy1-xFe2 (x ˜ 0.3, Terfenol-D), and ferroelectric barium strontium titanate (BST) including its paraelectric phase, for their energy conversion mechanisms. We grew and characterized these materials, followed by device fabrication to study potential energy conversion mechanisms in resulting devices. With Terfenol-D, we demonstrated a wireless energy-conversion process via the Villari effect, i.e. magnetic flux change induced by mechanical input. A new technique of transfer-printing a Terfenol-D film onto a flexible substrate was developed to study this mechanism. The transferred Terfenol-D showed a high saturation magnetization (˜ 1.3 T) and flexibility (strain ˜ 1.9 %). Subsequently, the Villari effect was successfully utilized to convert mechanical energy, from a mechanical source and a simulated biomechanical source, into electricity. For next projects, another ferroic material, a high-permittivity (dielectric constant ˜ 200) BST was sputtered on Pt/SiO2/Si or stainless steels to form a metal-insulator(BST)-metal heterostructure. The BST was found to be paraelectric when grown upon Pt/SiO2/Si, whereas it was ferroelectric when grown on the stainless steel. Two different mechanisms were therefore studied on these two modifications. In the paraelectric BST we found a new thermal-electric response via a flexoelectricity-mediated mechanism, which was enabled by a large strain gradient (> 104/m) produced by lattice mismatch. With the enhanced flexoelectricity from the large strain gradient, electrical output was generated under thermal cycling

  10. Absolute measurements of short-pulse, long-pulse, and capsule-implosion backlighter sources at x-ray energies greater than 10 keV

    NASA Astrophysics Data System (ADS)

    Maddox, Brian

    2010-11-01

    Laser-generated x-ray backlighters with x-ray energies > 10 keV are becoming essential diagnostic tools for many high energy density experiments. Examples include studies of high areal density cores for ignition designs, mid- to high-Z capsule implosion experiments, absolute equation of state experiments, dynamic diffraction under extreme pressures, and the study of material strength. Significant progress has been made recently using short pulse lasers, coupled to metal foil targets [1], and imploding capsules for producing high energy backlighters. Measuring the absolute x-ray flux and spectra from these sources is required for quantitative analysis of experimental data and for the design and planning of future experiments. We have performed an extensive series of experiments to measure the absolute x-ray flux and spectra on the Titan, Omega, Omega-EP, and NIF laser systems, employing single-photon-counting detectors, crystal spectrometers, and multichannel differential filtering (Ross-pair) and filter stack bremsstrahlung spectrometers. Calibrations were performed on these instruments [2] enabling absolute measurements of backlighter spectra to be made from 10 keV to 1 MeV. Various backlighter techniques that generate either quasi-monochromatic sources or broadband continuum sources will be presented and compared. For Molybdenum Kα backlighters at x-ray energy of ˜17 keV we measure conversion efficiencies of 1.3x10-4 using 1 μm wavelength short-pulse lasers at an intensity of ˜1x10^17 W/cm^2. This is a factor of ˜2 high than using 0.3 μm wavelength long-pulse lasers at an intensity of ˜1x10^16 W/cm^2. Other types of backlighter targets include capsule implosion backlighters that can generate a very bright ``white-light'' continuum x-ray source and high-Z gas filled capsules that generate a quasi-line-source of x rays. We will present and compare the absolute laser energy to x-ray conversion efficiencies for these different backlighter techniques and give

  11. Energy conversion of biomass in coping with global warming

    SciTech Connect

    Yokoyama, Shin-ya; Ogi, Tomoko; Minowa, Tomoaki

    1993-12-31

    The main purpose of the present paper is to propose energy conversion technologies of biomass in coping with global warming. Among thermochemical conversion, liquid fuel production by high pressure process is mainly introduced. Biomass is a term used to describe materials of biological origin, either purpose-grown or arising as by-products, residues or wastes from forestry, agriculture and food processing. Such biomass is a renewable energy sources dependent on solar energy. Through photosynthesis, plants converts carbon dioxide into organic materials used in their growth. Energy can be recovered from the plant materials by several processes, the simplest way is burning in air. As far as biomass is used in this way, there is no atmospheric accumulation of carbon dioxide making no effect on the Greenhouse Effect, provided that the cycle of regrowth and burning is sustained.

  12. Piezoelectric ribbons printed onto rubber for flexible energy conversion.

    PubMed

    Qi, Yi; Jafferis, Noah T; Lyons, Kenneth; Lee, Christine M; Ahmad, Habib; McAlpine, Michael C

    2010-02-10

    The development of a method for integrating highly efficient energy conversion materials onto stretchable, biocompatible rubbers could yield breakthroughs in implantable or wearable energy harvesting systems. Being electromechanically coupled, piezoelectric crystals represent a particularly interesting subset of smart materials that function as sensors/actuators, bioMEMS devices, and energy converters. Yet, the crystallization of these materials generally requires high temperatures for maximally efficient performance, rendering them incompatible with temperature-sensitive plastics and rubbers. Here, we overcome these limitations by presenting a scalable and parallel process for transferring crystalline piezoelectric nanothick ribbons of lead zirconate titanate from host substrates onto flexible rubbers over macroscopic areas. Fundamental characterization of the ribbons by piezo-force microscopy indicates that their electromechanical energy conversion metrics are among the highest reported on a flexible medium. The excellent performance of the piezo-ribbon assemblies coupled with stretchable, biocompatible rubber may enable a host of exciting avenues in fundamental research and novel applications.

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

    ERIC Educational Resources Information Center

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

    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.…

  14. Experiments to Determine the Efficiency of Various Energy Conversions.

    ERIC Educational Resources Information Center

    Curtis, D.; Goodwin, R. D.

    1980-01-01

    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)

  15. Quantitative evaluation of ocean thermal energy conversion (OTEC): executive briefing

    SciTech Connect

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

    1980-08-01

    Documentation is provided of a briefing summarizing the results of an independent quantitative evaluation of Ocean Thermal Energy Conversion (OTEC) for central station applications. The study concentrated on a central station power plant located in the Gulf of Mexico and delivering power to the mainland United States. The evaluation of OTEC is based on three important issues: resource availability, technical feasibility, and cost.

  16. Proceedings of the 27th intersociety energy conversion engineering conference

    SciTech Connect

    Not Available

    1992-01-01

    This book contains the proceedings of the 27th Intersociety Energy Conversion Engineering Conference. Topics included: Stirling Cycle Analysis; Stirling Cycle Models; Stirling Refrigerators/Heat Pumps and Cryocoolers; Domestic Policy; Efficiency/Conservation; Stirling Solar Terrestrial; Stirling Component Technology; Environmental Impacts; Renewable Resource Systems; Stirling Power Generation; Stirling Heat Transport System Technology; and Stirling Cycle Loss Understanding.

  17. Thermally driven electrokinetic energy conversion with liquid water microjets

    NASA Astrophysics Data System (ADS)

    Lam, Royce K.; Gamlieli, Zach; Harris, Stephen J.; Saykally, Richard J.

    2015-11-01

    A goal of current energy research is to design systems and devices that can efficiently exploit waste heat and utilize solar or geothermal heat energy for electrical power generation. We demonstrate a novel technique exploiting water's large coefficient of thermal expansion, wherein modest thermal gradients produce the requisite high pressure for driving fast-flowing liquid water microjets, which can effect the direct conversion of the kinetic energy into electricity and gaseous hydrogen. Waste heat in thermoelectric generating plants and combustion engines, as well as solar and geothermal energy could be used to drive these systems.

  18. Energy conversion/power plant cost-cutting

    SciTech Connect

    Nichols, K.

    1996-12-31

    This presentation by Kenneth Nichols, Barber-Nichols, Inc., is about cost-cutting in the energy conversion phase and power plant phase of geothermal energy production. Mr. Nichols discusses several ways in which improvements could be made, including: use of more efficient compressors and other equipment as they become available, anticipating reservoir resource decline and planning for it, running smaller binary systems independent of human operators, and designing plants so that they are relatively maintenance-free.

  19. Research and development on ocean thermal energy conversion in Japan

    SciTech Connect

    Uehara, H.

    1982-08-01

    The study of Ocean Thermal Energy Conversion (OTEC) in Japan has been conducted under the leadership of a team of the ''Sunshine Project'', a national new energy development project promoted by the Ministry of International Trade and Industries (MITI) since 1974. At present, two experimental OTEC power plants -Nauru's OTEC plant and Imari's OTEC plant are operating. In this paper, the review of research and development activity of these two OTEC plants in Japan is made.

  20. Saturation and energy-conversion efficiency of auroral kilometric radiation

    NASA Technical Reports Server (NTRS)

    Wu, C. S.; Tsai, S. T.; Xu, M. J.; Shen, J. W.

    1981-01-01

    A quasi-linear theory is used to study the saturation level of the auroral kilometric radiation. The investigation is based on the assumption that the emission is due to a cyclotron maser instability as suggested by Wu and Lee and Lee et al. The thermodynamic bound on the radiation energy is also estimated separately. The energy-conversion efficiency of the radiation process is discussed. The results are consistent with observations.

  1. Fast GPU-based absolute intensity determination for energy-dispersive X-ray Laue diffraction

    NASA Astrophysics Data System (ADS)

    Alghabi, F.; Send, S.; Schipper, U.; Abboud, A.; Pietsch, U.; Kolb, A.

    2016-01-01

    This paper presents a novel method for fast determination of absolute intensities in the sites of Laue spots generated by a tetragonal hen egg-white lysozyme crystal after exposure to white synchrotron radiation during an energy-dispersive X-ray Laue diffraction experiment. The Laue spots are taken by means of an energy-dispersive X-ray 2D pnCCD detector. Current pnCCD detectors have a spatial resolution of 384 × 384 pixels of size 75 × 75 μm2 each and operate at a maximum of 400 Hz. Future devices are going to have higher spatial resolution and frame rates. The proposed method runs on a computer equipped with multiple Graphics Processing Units (GPUs) which provide fast and parallel processing capabilities. Accordingly, our GPU-based algorithm exploits these capabilities to further analyse the Laue spots of the sample. The main contribution of the paper is therefore an alternative algorithm for determining absolute intensities of Laue spots which are themselves computed from a sequence of pnCCD frames. Moreover, a new method for integrating spectral peak intensities and improved background correction, a different way of calculating mean count rate of the background signal and also a new method for n-dimensional Poisson fitting are presented.We present a comparison of the quality of results from the GPU-based algorithm with the quality of results from a prior (base) algorithm running on CPU. This comparison shows that our algorithm is able to produce results with at least the same quality as the base algorithm. Furthermore, the GPU-based algorithm is able to speed up one of the most time-consuming parts of the base algorithm, which is n-dimensional Poisson fitting, by a factor of more than 3. Also, the entire procedure of extracting Laue spots' positions, energies and absolute intensities from a raw dataset of pnCCD frames is accelerated by a factor of more than 3.

  2. Future of photovoltaic energy conversion in developing countries

    SciTech Connect

    Hogan, S.

    1980-04-01

    Recent studies reveal that photovoltaic energy conversion will be economically viable for usage in developing countries. An overview of programs designed to lower the costs of such conversion systems is presented. Government goals are reviewed, as well as application projects relative to rural usage. A summary of the state-of-the-art in both advanced research and commercially available technology is presented. It is concluded that with the range of the work being done, such systems will be viable for many rural applications within 5 years.

  3. Advanced materials for high-temperature thermoelectric energy conversion

    NASA Technical Reports Server (NTRS)

    Vining, Cronin B.; Vandersande, Jan W.; Wood, Charles

    1992-01-01

    A number of refractory semiconductors are under study at the Jet Propulsion Laboratory for application in thermal to electric energy conversion for space power. The main thrust of the program is to improve or develop materials of high figure of merit and, therefore, high conversion efficiencies over a broad temperature range. Materials currently under investigation are represented by silicon-germanium alloys, lanthanum telluride, and boron carbide. The thermoelectric properties of each of these materials, and prospects for their further improvements, are discussed. Continued progress in thermoelectric materials technology can be expected to yield reliable space power systems with double to triple the efficiency of current state of the art systems.

  4. SPS energy conversion and power management workshop. Final report

    SciTech Connect

    Not Available

    1980-06-01

    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)

  5. Oxygen electrochemistry as a cornerstone for sustainable energy conversion.

    PubMed

    Katsounaros, Ioannis; Cherevko, Serhiy; Zeradjanin, Aleksandar R; Mayrhofer, Karl J J

    2014-01-03

    Electrochemistry will play a vital role in creating sustainable energy solutions in the future, particularly for the conversion and storage of electrical into chemical energy in electrolysis cells, and the reverse conversion and utilization of the stored energy in galvanic cells. The common challenge in both processes is the development of-preferably abundant-nanostructured materials that can catalyze the electrochemical reactions of interest with a high rate over a sufficiently long period of time. An overall understanding of the related processes and mechanisms occurring under the operation conditions is a necessity for the rational design of materials that meet these requirements. A promising strategy to develop such an understanding is the investigation of the impact of material properties on reaction activity/selectivity and on catalyst stability under the conditions of operation, as well as the application of complementary in situ techniques for the investigation of catalyst structure and composition.

  6. Multiple-junction quantum cascade photodetectors for thermophotovoltaic energy conversion.

    PubMed

    Yin, Jian; Paiella, Roberto

    2010-01-18

    The use of intersubband transitions in quantum cascade structures for thermophotovoltaic energy conversion is investigated numerically. The intrinsic cascading scheme, spectral agility, and design flexibility of these structures make them ideally suited to the development of high efficiency multiple-junction thermophotovoltaic detectors. A specific implementation of this device concept is designed, based on bound-to-continuum intersubband transitions in large-conduction-band-offset In(0.7)Ga(0.3)As/AlAs(0.8)Sb(0.2) quantum wells. The device electrical characteristics in the presence of thermal radiation from a blackbody source at 1300 K are calculated, from which a maximum extracted power density of 1.4 W/cm(2) is determined. This value compares favorably with the present state-of-the-art in interband thermophotovoltaic energy conversion, indicating that quantum cascade photodetectors may provide a promising approach to improve energy extraction from thermal sources.

  7. Magnetic energy storage and conversion in the solar atmosphere

    NASA Technical Reports Server (NTRS)

    Spicer, D. S.; Mariska, J. T.; Boris, J. P.

    1986-01-01

    According to the approach employed in this investigation, particularly important simple configurations of magnetic field and plasma are identified, and it is attempted to achieve an understanding of the large-scale dynamic processes and transformations which these systems can undergo. Fundamental concepts are discussed, taking into account aspects of magnetic energy generation, ideal MHD theory, non-MHD properties, the concept of 'anomalous' resistivity, and global electrodynamic coupling. Questions of magnetically controlled energy conversion are examined, giving attention to magnetic modifications of plasma transport, the transition region structure and flows, channeling and acceleration of plasma, channeling and dissipation of MHD waves, and anomalous dissipation of field-aligned currents. A description of the characteristics of magnetohydrodynamic energy conversion is also provided, and outstanding questions are discussed.

  8. Superharp — A wire scanner with absolute position readout for beam energy measurement at CEBAF

    NASA Astrophysics Data System (ADS)

    Yan, C.; Adderley, P.; Barker, D.; Beaufait, J.; Capek, K.; Carlini, R.; Dahlberg, J.; Feldl, E.; Jordan, K.; Kross, B.; Oren, W.; Wojcik, R.; VanDyke, J.

    1995-02-01

    The CEBAF superharp is an upgraded beam wire scanner which provides absolute beam position readout using a shaft encoder. Superharps allow for high precision measurements of the beam's profile and position ( Δx ˜ 10 μm). The Hall C endstation at CEBAF will use three pairs of superharps to perform beam energy measurements with 10 -3 accuracy. The three pairs are installed at the beginning, the mid-point and the end of the Hall C arc beamline. Using superharps in conjunction with a dual sensor system: the direct current pick-up and the bremsstrahlung detectors, beam profile measurements can be obtained over a wide beam current range of 1 ˜ 200 μA.

  9. Absolutely continuous energy bands in the electronic spectrum of quasiperiodic ladder networks

    NASA Astrophysics Data System (ADS)

    Pal, Biplab; Chakrabarti, Arunava

    2014-06-01

    The energy spectra of quasi-one-dimensional quasiperiodic ladder networks are analyzed within a tight binding description. In particular, we show that if a selected set of sites in each strand of a ladder is tunnel-coupled to quantum dots attached from a side, absolutely continuous subbands can be generated in the spectrum if one tunes the dot potential and the dot-strand coupling appropriately. Typical cases with two and three strand Fibonacci ladders in the off-diagonal model are discussed in details. We also discuss the possibility of re-entrant insulator-metal transition for a general n-strand ladder network when n becomes large. The observations remain valid even in the case of a disordered ladder network with the same constituents. The results are analytically exact.

  10. Absolute measurement of the relativistic magnetic dipole transition energy in heliumlike argon.

    PubMed

    Amaro, Pedro; Schlesser, Sophie; Guerra, Mauro; Le Bigot, Eric-Olivier; Isac, Jean-Michel; Travers, Pascal; Santos, José Paulo; Szabo, Csilla I; Gumberidze, Alexandre; Indelicato, Paul

    2012-07-27

    The 1s2s (3)S(1)→1s(2) (1)S(0) relativistic magnetic dipole transition in heliumlike argon, emitted by the plasma of an electron-cyclotron resonance ion source, has been measured using a double-flat crystal x-ray spectrometer. Such a spectrometer, used for the first time on a highly charged ion transition, provides absolute (reference-free) measurements in the x-ray domain. We find a transition energy of 3104.1605(77) eV (2.5 ppm accuracy). This value is the most accurate, reference-free measurement done for such a transition and is in good agreement with recent QED predictions.

  11. Database applicaton for absolute spectrophotometry

    NASA Astrophysics Data System (ADS)

    Bochkov, Valery V.; Shumko, Sergiy

    2002-12-01

    32-bit database application with multidocument interface for Windows has been developed to calculate absolute energy distributions of observed spectra. The original database contains wavelength calibrated observed spectra which had been already passed through apparatus reductions such as flatfielding, background and apparatus noise subtracting. Absolute energy distributions of observed spectra are defined in unique scale by means of registering them simultaneously with artificial intensity standard. Observations of sequence of spectrophotometric standards are used to define absolute energy of the artificial standard. Observations of spectrophotometric standards are used to define optical extinction in selected moments. FFT algorithm implemented in the application allows performing convolution (deconvolution) spectra with user-defined PSF. The object-oriented interface has been created using facilities of C++ libraries. Client/server model with Windows Socket functionality based on TCP/IP protocol is used to develop the application. It supports Dynamic Data Exchange conversation in server mode and uses Microsoft Exchange communication facilities.

  12. Photon energy conversion efficiency in gamma-ray spectrometry.

    PubMed

    Švec, Anton

    2016-01-01

    Photon energy conversion efficiency coefficient is presented as the ratio of total energy registered in the collected spectrum to the emitted photon energy. This parameter is calculated from the conventional gamma-ray histogram and in principle is not affected by coincidence phenomena. This feature makes it particularly useful for calibration and measurement of radionuclide samples at close geometries. It complements the number of efficiency parameters used in gamma-ray spectrometry and can partly change the view as to how the gamma-ray spectra are displayed and processed.

  13. Buckled graphene for efficient energy harvest, storage and conversion.

    PubMed

    Jiang, Jin-Wu

    2016-10-07

    Buckling is one of the most common phenomena in atom-thick layered structures like graphene. While the buckling phenomenon usually causes disaster for most nanodevices, we illustrate one positive application of buckled graphene for energy harvest, storage and conversion. More specifically, we perform molecular dynamical simulations to show that buckled graphene can be used to collect wasted mechanical energy and store the energy in the form of internal knotting potential. Through strain engineering, the knotting potential can be converted into useful kinetic (thermal) energy that is highly concentrated at the free edges of buckled graphene. The present study demonstrates potential applications of buckled graphene for converting dispersed wasted mechanical energy into concentrated useful kinetic (thermal) energy.

  14. Buckled graphene for efficient energy harvest, storage and conversion

    NASA Astrophysics Data System (ADS)

    Jiang, Jin-Wu

    2016-10-01

    Buckling is one of the most common phenomena in atom-thick layered structures like graphene. While the buckling phenomenon usually causes disaster for most nanodevices, we illustrate one positive application of buckled graphene for energy harvest, storage and conversion. More specifically, we perform molecular dynamical simulations to show that buckled graphene can be used to collect wasted mechanical energy and store the energy in the form of internal knotting potential. Through strain engineering, the knotting potential can be converted into useful kinetic (thermal) energy that is highly concentrated at the free edges of buckled graphene. The present study demonstrates potential applications of buckled graphene for converting dispersed wasted mechanical energy into concentrated useful kinetic (thermal) energy.

  15. Plasmon-induced resonance energy transfer for solar energy conversion

    NASA Astrophysics Data System (ADS)

    Li, Jiangtian; Cushing, Scott K.; Meng, Fanke; Senty, Tess R.; Bristow, Alan D.; Wu, Nianqiang

    2015-09-01

    In Förster resonance energy transfer (FRET), energy non-radiatively transfers from a blue-shifted emitter to a red-shifted absorber by dipole-dipole coupling. This study shows that plasmonics enables the opposite transfer direction, transferring the plasmonic energy towards the short-wavelength direction to induce charge separation in a semiconductor. Plasmon-induced resonance energy transfer (PIRET) differs from FRET because of the lack of a Stoke's shift, non-local absorption effects and a strong dependence on the plasmon's dephasing rate and dipole moment. PIRET non-radiatively transfers energy through an insulating spacer layer, which prevents interfacial charge recombination losses and dephasing of the plasmon from hot-electron transfer. The distance dependence of dipole-dipole coupling is mapped out for a range of detuning across the plasmon resonance. PIRET can efficiently harvest visible and near-infrared sunlight with energy below the semiconductor band edge to help overcome the constraints of band-edge energetics for single semiconductors in photoelectrochemical cells, photocatalysts and photovoltaics.

  16. Adaptability of solar energy conversion systems on ships

    NASA Astrophysics Data System (ADS)

    Visa, I.; Cotorcea, A.; Neagoe, M.; Moldovan, M.

    2016-08-01

    International trade of goods largely uses maritime/transoceanic ships driven by engines using fossil fuels. This two centuries tradition is technologically mature but significantly adds to the CO2 emissions; therefore, recent trends focus on on-board implementation of systems converting the solar energy into power (photovoltaic systems) or heat (solar-thermal systems). These systems are carbon-emissions free but are still under research and plenty of effort is devoted to fast reach maturity and feasibility. Unlike the systems implemented in a specific continental location, the design of solar energy conversion systems installed on shipboard has to face the problem generated by the system base motion along with the ship travelling on routes at different latitudes: the navigation direction and sense and roll-pitch combined motion with reduced amplitude, but with relatively high frequency. These raise highly interesting challenges in the design and development of mechanical systems that support the maximal output in terms of electricity or heat. The paper addresses the modelling of the relative position of a solar energy conversion surface installed on a ship according to the current position of the sun; the model is based on the navigation trajectory/route, ship motion generated by waves and the relative sun-earth motion. The model describes the incidence angle of the sunray on the conversion surface through five characteristic angles: three used to define the ship orientation and two for the solar angles; based on, their influence on the efficiency in solar energy collection is analyzed by numerical simulations and appropriate recommendations are formulated for increasing the solar energy conversion systems adaptability on ships.

  17. Assessing the quality of absolute hydration free energies among CHARMM-compatible ligand parameterization schemes.

    PubMed

    Knight, Jennifer L; Yesselman, Joseph D; Brooks, Charles L

    2013-04-30

    Multipurpose atom-typer for CHARMM (MATCH), an atom-typing toolset for molecular mechanics force fields, was recently developed in our laboratory. Here, we assess the ability of MATCH-generated parameters and partial atomic charges to reproduce experimental absolute hydration free energies for a series of 457 small neutral molecules in GBMV2, Generalized Born with a smooth SWitching (GBSW), and fast analytical continuum treatment of solvation (FACTS) implicit solvent models. The quality of hydration free energies associated with small molecule parameters obtained from ParamChem, SwissParam, and Antechamber are compared. Given optimized surface tension coefficients for scaling the surface area term in the nonpolar contribution, these automated parameterization schemes with GBMV2 and GBSW demonstrate reasonable agreement with experimental hydration free energies (average unsigned errors of 0.9-1.5 kcal/mol and R(2) of 0.63-0.87). GBMV2 and GBSW consistently provide slightly more accurate estimates than FACTS, whereas Antechamber parameters yield marginally more accurate estimates than the current generation of MATCH, ParamChem, and SwissParam parameterization strategies. Modeling with MATCH libraries that are derived from different CHARMM topology and parameter files highlights the importance of having sufficient coverage of chemical space within the underlying databases of these automated schemes and the benefit of targeting specific functional groups for parameterization efforts to maximize both the breadth and the depth of the parameterized space.

  18. Setting Whole-Building Absolute Energy Use Targets for the K-12 School, Retail, and Healthcare Sectors: Preprint

    SciTech Connect

    Leach, M.; Bonnema, E.; Pless, S.; Torcellini, P.

    2012-08-01

    This paper helps owners' efficiency representatives to inform executive management, contract development, and project management staff as to how specifying and applying whole-building absolute energy use targets for new construction or renovation projects can improve the operational energy performance of commercial buildings.

  19. Spectral light management for solar energy conversion systems

    NASA Astrophysics Data System (ADS)

    Stanley, Cameron; Mojiri, Ahmad; Rosengarten, Gary

    2016-06-01

    Due to the inherent broadband nature of the solar radiation, combined with the narrow spectral sensitivity range of direct solar to electricity devices, there is a massive opportunity to manipulate the solar spectrum to increase the functionality and efficiency of solar energy conversion devices. Spectral splitting or manipulation facilitates the efficient combination of both high-temperature solar thermal systems, which can absorb over the entire solar spectrum to create heat, and photovoltaic cells, which only convert a range of wavelengths to electricity. It has only recently been possible, with the development of nanofabrication techniques, to integrate micro- and nano-photonic structures as spectrum splitters/manipulators into solar energy conversion devices. In this paper, we summarize the recent developments in beam splitting techniques, and highlight some relevant applications including combined PV-thermal collectors and efficient algae production, and suggest paths for future development in this field.

  20. The total flow concept for geothermal energy conversion

    NASA Technical Reports Server (NTRS)

    Austin, A. L.

    1974-01-01

    A geothermal development project has been initiated at the Lawrence Livermore Laboratory (LLL) to emphasize development of methods for recovery and conversion of the energy in geothermal deposits of hot brines. Temperatures of these waters vary from 150 C to more than 300 C with dissolved solids content ranging from less than 0.1% to over 25% by weight. Of particular interest are the deposits of high-temperature/high-salinity brines, as well as less saline brines, known to occur in the Salton Trough of California. Development of this resource will depend on resolution of the technical problems of brine handling, scale and precipitation control, and corrosion/erosion resistant systems for efficient conversion of thermal to electrical energy. Research experience to date has shown these problems to be severe. Hence, the LLL program emphasizes development of an entirely different approach called the Total Flow concept.

  1. Transition Metal Carbides and Nitrides in Energy Storage and Conversion.

    PubMed

    Zhong, Yu; Xia, Xinhui; Shi, Fan; Zhan, Jiye; Tu, Jiangping; Fan, Hong Jin

    2016-05-01

    High-performance electrode materials are the key to advances in the areas of energy conversion and storage (e.g., fuel cells and batteries). In this Review, recent progress in the synthesis and electrochemical application of transition metal carbides (TMCs) and nitrides (TMNs) for energy storage and conversion is summarized. Their electrochemical properties in Li-ion and Na-ion batteries as well as in supercapacitors, and electrocatalytic reactions (oxygen evolution and reduction reactions, and hydrogen evolution reaction) are discussed in association with their crystal structure/morphology/composition. Advantages and benefits of nanostructuring (e.g., 2D MXenes) are highlighted. Prospects of future research trends in rational design of high-performance TMCs and TMNs electrodes are provided at the end.

  2. Quantum dot nanoscale heterostructures for solar energy conversion.

    PubMed

    Selinsky, Rachel S; Ding, Qi; Faber, Matthew S; Wright, John C; Jin, Song

    2013-04-07

    Quantum dot nanoscale semiconductor heterostructures (QDHs) are a class of materials potentially useful for integration into solar energy conversion devices. However, realizing the potential of these heterostructured systems requires the ability to identify and synthesize heterostructures with suitably designed materials, controlled size and morphology of each component, and structural control over their shared interface. In this review, we will present the case for the utility and advantages of chemically synthesized QDHs for solar energy conversion, beginning with an overview of various methods of heterostructured material synthesis and a survey of heretofore reported materials systems. The fundamental charge transfer properties of the resulting materials combinations and their basic design principles will be outlined. Finally, we will discuss representative solar photovoltaic and photoelectrochemical devices employing QDHs (including quantum dot sensitized solar cells, or QDSSCs) and examine how QDH synthesis and design impacts their performance.

  3. Thermoelectric Energy Conversion: Future Directions and Technology Development Needs

    NASA Technical Reports Server (NTRS)

    Fleurial, Jean-Pierre

    2007-01-01

    This viewgraph presentation reviews the process of thermoelectric energy conversion along with key technology needs and challenges. The topics include: 1) The Case for Thermoelectrics; 2) Advances in Thermoelectrics: Investment Needed; 3) Current U.S. Investment (FY07); 4) Increasing Thermoelectric Materials Conversion Efficiency Key Science Needs and Challenges; 5) Developing Advanced TE Components & Systems Key Technology Needs and Challenges; 6) Thermoelectrics; 7) 200W Class Lightweight Portable Thermoelectric Generator; 8) Hybrid Absorption Cooling/TE Power Cogeneration System; 9) Major Opportunities in Energy Industry; 10) Automobile Waste Heat Recovery; 11) Thermoelectrics at JPL; 12) Recent Advances at JPL in Thermoelectric Converter Component Technologies; 13) Thermoelectrics Background on Power Generation and Cooling Operational Modes; 14) Thermoelectric Power Generation; and 15) Thermoelectric Cooling.

  4. Transition Metal Carbides and Nitrides in Energy Storage and Conversion

    PubMed Central

    Zhong, Yu; Shi, Fan; Zhan, Jiye; Tu, Jiangping

    2016-01-01

    High‐performance electrode materials are the key to advances in the areas of energy conversion and storage (e.g., fuel cells and batteries). In this Review, recent progress in the synthesis and electrochemical application of transition metal carbides (TMCs) and nitrides (TMNs) for energy storage and conversion is summarized. Their electrochemical properties in Li‐ion and Na‐ion batteries as well as in supercapacitors, and electrocatalytic reactions (oxygen evolution and reduction reactions, and hydrogen evolution reaction) are discussed in association with their crystal structure/morphology/composition. Advantages and benefits of nanostructuring (e.g., 2D MXenes) are highlighted. Prospects of future research trends in rational design of high‐performance TMCs and TMNs electrodes are provided at the end. PMID:27812464

  5. Design of nitride semiconductors for solar energy conversion

    SciTech Connect

    Zakutayev, Andriy

    2016-01-01

    Nitride semiconductors are a promising class of materials for solar energy conversion applications, such as photovoltaic and photoelectrochemical cells. Nitrides can have better solar absorption and electrical transport properties than the more widely studied oxides, as well as the potential for better scalability than other pnictides or chalcogenides. In addition, nitrides are also relatively unexplored compared to other chemistries, so they provide a great opportunity for new materials discovery. This paper reviews the recent advances in the design of novel semiconducting nitrides for solar energy conversion technologies. Both binary and multinary nitrides are discussed, with a range of metal chemistries (Cu3N, ZnSnN2, Sn3N4, etc.) and crystal structures (delafossite, perovskite, spinel, etc.), including a brief overview of wurtzite III-N materials and devices. The current scientific challenges and promising future directions in the field are also highlighted.

  6. Energy transfer processes in solar energy conversion. Final report

    SciTech Connect

    Fayer, M.D.

    1984-01-01

    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)

  7. Advanced Energy Conversion Concept for Beamed-Energy Propulsion.

    DTIC Science & Technology

    1987-08-21

    geometry ................ 9 Figure HA Methods for incorporating variable geometry In radlally-eymmetric supersonic inlets...41 Figure 11. EB thrust vector geometry for rotating ine source(s) ... ........... 42 Ire 11-19. Energy deposition mode - bottom view...coniguration . ..... ................... 106 Figure V.2. LSD wave Laraglan view ..... ....................... 105 Figure V-.& Cylindrical blad wave geometry

  8. Conversion of concentrated solar thermal energy into chemical energy.

    PubMed

    Tamaura, Yutaka

    2012-01-01

    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 (α-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.

  9. A study of water electrolysis with photovoltaic solar energy conversion

    NASA Astrophysics Data System (ADS)

    Carpetis, C.

    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 conditions of the system solar array electrolysis unit is formulated to allow conclusions of general validity.

  10. PHOTOVOLTAIC AND THERMOELECTRIC SOLAR ENERGY CONVERSION USING THIN FILMS,

    DTIC Science & Technology

    Solar energy conversion by the use of thin films in photovoltaic and thermoelectric devices is discussed. Experimental work is presented on the fabrication of a thin film cadmium sulfide cell which utilizes the photovoltaic effect. A theoretical investigation is made of the temperature differences obtainable in space by using thin, light-weight plastic sheets, and the use of such plastics for thermoelectric generators is discussed. Temperature differences of several hundred centrigrade degrees can be obtained. (Author)

  11. Magnetohydrodynamic energy conversion by using convexly divergent channel

    NASA Astrophysics Data System (ADS)

    Murakami, Tomoyuki; Okuno, Yoshihiro

    2009-12-01

    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.

  12. Solar energy conversion in photoelectrochemical cells with semiconductor electrodes

    NASA Astrophysics Data System (ADS)

    Pleskov, Yu. V.

    in recent years the semiconductor/electrolyte interface has been attracting much attention in connection with the search for effective ways of utilizing solar energy. This review systematizes information on photoelectrochemical cells, both for production of hydrogen by water photoelectrolysis and for electric power generation in “liquid-junction solar cells.” Special attention is given to integral characteristics of photoelectrochemical cells. The main difficulties in practical realization of the conversion process and some possible methods of surmounting them are formulated.

  13. Thermophotovoltaic energy conversion using photonic bandgap selective emitters

    DOEpatents

    Gee, James M.; Lin, Shawn-Yu; Fleming, James G.; Moreno, James B.

    2003-06-24

    A method for thermophotovoltaic generation of electricity comprises heating a metallic photonic crystal to provide selective emission of radiation that is matched to the peak spectral response of a photovoltaic cell that converts the radiation to electricity. The use of a refractory metal, such as tungsten, for the photonic crystal enables high temperature operation for high radiant flux and high dielectric contrast for a full 3D photonic bandgap, preferable for efficient thermophotovoltaic energy conversion.

  14. Data Analysis for Ocean Thermal Energy Conversion (otec)

    DTIC Science & Technology

    1979-11-01

    Unit Number 01. The author wishes to thank Mr. David Boswell of DTNSRDC, Annapolis, Maryland for his work on OTEC software development. The...assistance of Mr. Glenn Grannemann of Carnegie-Mellon University, Pittsburgh, Pennsylvania, in reviewing Panama City OTEC data analysis techniques is...FOR OCEAN THERMAL ENERGY Technical Memodnndum CONVERSION ( OTEC ) , * IERFORMING Ono, XCIPOOT mulesea 7. AUTNORf.) .. CONTRACT OR GRANT S411jbdb .ftf

  15. Magnetohydrodynamic energy conversion by using convexly divergent channel

    SciTech Connect

    Murakami, Tomoyuki; Okuno, Yoshihiro

    2009-12-21

    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.

  16. Thermodynamic limits to the conversion of blackbody radiation by quantum systems. [with application to solar energy conversion devices

    NASA Technical Reports Server (NTRS)

    Buoncristiani, A. M.; Smith, B. T.; Byvik, C. E.

    1982-01-01

    Using general thermodynamic arguments, we analyze the conversion of the energy contained in the radiation from a blackbody to useful work by a quantum system. We show that the energy available for conversion is bounded above by the change in free energy in the incident and reradiated fields and that this free energy change depends upon the temperature of the receiving device. Universal efficiency curves giving the ultimate thermodynamic conversion efficiency of the quantum system are presented in terms of the blackbody temperature and the temperature and threshold energy of the quantum system. Application of these results is made to a variety of systems including biological photosynthetic, photovoltaic, and photoelectrochemical systems.

  17. Plasmonic Nanomaterials for Optical-to-Electrical Energy Conversion

    NASA Astrophysics Data System (ADS)

    Sheldon, Matthew

    High-quality semiconductor solids have been the dominant photovoltaic materials platform for decades. Although several alternative approaches have been proposed, e.g. dye-sensitized cells or polymeric solids, none compete in terms of cost and conversion efficiency, the crucial benchmarks for industrial scale implementation. However, semiconductors suffer from several fundamental limitations relating to the microscopic mechanism of power conversion that preclude them, even theoretically, from achieving conversion efficiency at the Carnot limit of 95%. Indeed, the fundamentally different tasks of semiconductors in photovoltaic devices, both as optical absorbers, and separately, for electron-hole pair separation and collection, often demand opposing trade-offs in materials optimization. Alternatively, recent advances in subwavelength metal optics, e.g. nanophotonics, metamaterials, and plasmonics, provide several new examples where nanostructured metals perform the separate tasks of absorption and charge separation necessary for photovoltaic power conversion. Nanostructured metals are extremely efficient broadband absorbers of radiation, with tailorable optical properties throughout the visible and infrared spectrum. It is traditionally assumed that the lack of a band gap and consequent fast electronic relaxation (fs) and short mean free path (100 nm) hinders efficient carrier collection. However, new phenomena resulting from the remarkable energy concentration and nanoscale collection geometry afforded by plasmonic systems suggest new strategies may be possible that use all metal structures. In this talk, I will describe two ongoing studies in our laboratory that exemplify opportunities for metal-based optical energy conversion: (1) Excitation with circularly polarized illumination can induce strong, persistent electrical drift currents in resonant metal nanostructures via the inverse faraday effect. (2) Plasmonic absorption in metal nanostructures provides an

  18. Absolute x-ray energy calibration over a wide energy range using a diffraction-based iterative method.

    PubMed

    Hong, Xinguo; Chen, Zhiqiang; Duffy, Thomas S

    2012-06-01

    In this paper, we report a method of precise and fast absolute x-ray energy calibration over a wide energy range using an iterative x-ray diffraction based method. Although accurate x-ray energy calibration is indispensable for x-ray energy-sensitive scattering and diffraction experiments, there is still a lack of effective methods to precisely calibrate energy over a wide range, especially when normal transmission monitoring is not an option and complicated micro-focusing optics are fixed in place. It is found that by using an iterative algorithm the x-ray energy is only tied to the relative offset of sample-to-detector distance, which can be readily varied with high precision of the order of 10(-5) -10(-6) spatial resolution using gauge blocks. Even starting with arbitrary initial values of 0.1 Å, 0.3 Å, and 0.4 Å, the iteration process converges to a value within 3.5 eV for 31.122 keV x-rays after three iterations. Different common diffraction standards CeO(2), Au, and Si show an energy deviation of 14 eV. As an application, the proposed method has been applied to determine the energy-sensitive first sharp diffraction peak of network forming GeO(2) glass at high pressure, exhibiting a distinct behavior in the pressure range of 2-4 GPa. Another application presented is pair distribution function measurement using calibrated high-energy x-rays at 82.273 keV. Unlike the traditional x-ray absorption-based calibration method, the proposed approach does not rely on any edges of specific elements, and is applicable to the hard x-ray region where no appropriate absorption edge is available.

  19. Efficiency of luminous-energy conversion in semiconducting photoelectrochemical converters

    SciTech Connect

    Kireev, V.B.; Trukhan, E.M.; Filimonov, D.A.

    1981-03-01

    Factors characterizing the conversion efficiency of luminous into chemical energy in semiconducting photoelectrochemical converters are examined. An expression for /gamma/sub //O is discussed in particular; /gamma/sub //O is the quantum yield of photocurrent of the minority carriers sustaining the reaction during which chemical energy is accumulated. The expression for /gamma/sub //O allows, both for the finite rate of electrode surface processes and for recombination in the semiconductor's space-charge layer. It is shown that over a wide range of converter parameters, recombination in the space-charge layer is one of the most important factors for the size of /gamma/sub //O. 17 refs.

  20. Longitudinal Density Modulation and Energy Conversion in Intense Beams

    SciTech Connect

    Harris, J; Neumann, J; Tian, K; O'Shea, P

    2006-02-17

    Density modulation of charged particle beams may occur as a consequence of deliberate action, or may occur inadvertently because of imperfections in the particle source or acceleration method. In the case of intense beams, where space charge and external focusing govern the beam dynamics, density modulation may under some circumstances be converted to velocity modulation, with a corresponding conversion of potential energy to kinetic energy. Whether this will occur depends on the properties of the beam and the initial modulation. This paper describes the evolution of discrete and continuous density modulations on intense beams, and discusses three recent experiments related to the dynamics of density-modulated electron beams.

  1. Surface Immobilization of Molecular Electrocatalysts for Energy Conversions.

    PubMed

    Bullock, Morris; Das, Atanu K; Appel, Aaron M

    2017-02-08

    Electrocatalysts are critically important for a secure energy future, as they facilitate the conversion between electrical and chemical energy. Molecular catalysts offer precise control of structure that enables understanding of structure-reactivity relationships, which can be difficult to achieve with heterogeneous catalysts. Molecular electrocatalysts can be immobilized on surfaces by covalent bonds or through non-covalent interactions. Advantages of surface immobilization include the need for less catalyst, avoidance of bimolecular decomposition pathways, and easier determination of catalyst lifetime. This mini-review highlights surface immobilization of molecular electrocatalysts for reduction of O2, oxidation of H2O, production of H2, and reduction of CO2.

  2. ELENA MCP detector: absolute detection efficiency for low-energy neutral atoms

    NASA Astrophysics Data System (ADS)

    Rispoli, R.; De Angelis, E.; Colasanti, L.; Vertolli, N.; Orsini, S.; Scheer, J. A.; Mura, A.; Milillo, A.; Wurz, P.; Selci, S.; Di Lellis, A. M.; Leoni, R.; D'Alessandro, M.; Mattioli, F.; Cibella, S.

    2012-09-01

    Microchannel Plates (MCP) detectors are frequently used in space instrumentation for detecting a wide range of radiation and particles. In particular, the capability to detect non-thermal low energy neutral species is crucial for the sensor ELENA (Emitted Low-Energy Neutral Atoms), part of the package SERENA (Search for Exospheric Refilling and Emitted Natural Abundances) on board the BepiColombo mission of ESA to Mercury to be launched in 2015. ELENA is a Time of Flight (TOF) sensor, based on a novel concept using an ultra-sonic oscillating shutter (Start section), which is operated at frequencies up to 50 kHz; a MCP detector is used as a Stop detector. The scientific objective of ELENA is to detect energetic neutral atoms in the range 10 eV - 5 keV, within 76° FOV, perpendicular to the S/C orbital plane. ELENA will monitor the emission of neutral atoms from the whole surface of Mercury thanks to the spacecraft motion. The major scientific objectives are the interaction between the plasma environment and the planet’s surface, the global particle loss-rate and the remote sensing of the surface properties. In particular, surface release processes are investigated by identifying particles released from the surface, via solar wind-induced ion sputtering (< 1eV - < 100 eV) as well as Hydrogen back-scattered at hundreds eV. MCP absolute detection efficiency for very low energy neutral atoms (E < 30 eV) is a crucial point for this investigation. At the MEFISTO facility of the Physical Institute of the University of Bern (CH), measurements on three different types of MCP (with and without coating) have been performed providing the detection efficiencies in the energy range 10eV - 1keV. Outcomes from such measurements are discussed here.

  3. An estimate of spherical impactor energy transfer for mechanical frequency up-conversion energy harvester

    NASA Astrophysics Data System (ADS)

    Corr, L. R.; Ma, D. T.

    2016-08-01

    Vibration energy harvesters, which use the impact mechanical frequency up-conversion technique, utilize an impactor, which gains kinetic energy from low frequency ambient environmental vibrations, to excite high frequency systems that efficiently convert mechanical energy to electrical energy. To take full advantage of the impact mechanical frequency up-conversion technique, it is prudent to understand the energy transfer from the low frequency excitations, to the impactor, and finally to the high frequency systems. In this work, the energy transfer from a spherical impactor to a multi degree of freedom spring / mass system, due to Hertzian impact, is investigated to gain insight on how best to design impact mechanical frequency up-conversion energy harvesters. Through this academic work, it is shown that the properties of the contact (or impact) area, i.e., radius of curvature and material properties, only play a minor role in energy transfer and that the equivalent mass of the target system (i.e., the spring / mass system) dictates the total amount of energy transferred during the impact. The novel approach of utilizing the well-known Hertzian impact methodology to gain an understanding of impact mechanical frequency up-conversion energy harvesters has made it clear that the impactor and the high frequency energy generating systems must be designed together as one system to ensure maximum energy transfer, leading to efficient ambient vibration energy harvesters.

  4. Electroelastodynamics of flexoelectric energy conversion and harvesting in elastic dielectrics

    NASA Astrophysics Data System (ADS)

    Moura, Adriane G.; Erturk, Alper

    2017-02-01

    Flexoelectricity is the generation of electric polarization by the application of a non-uniform mechanical strain field, i.e., a strain gradient. This phenomenon is exhibited by all elastic dielectrics, but is expected to be significant only at very small scales. Energy harvesting is a potential future application area of flexoelectricity to enable next-generation ultra-low-power MEMS/NEMS devices by converting ambient vibrations into electricity. In this paper, an electroelastodynamic framework is presented and analyzed for flexoelectric energy harvesting from strain gradient fluctuations in centrosymmetric dielectrics, by accounting for the presence of a finite electrical load across the surface electrodes as well as two-way electromechanical coupling, and capturing the size effect. The flexoelectric energy harvester model is based on the Euler-Bernoulli beam theory and it assumes the main source of polarization to be static bulk flexoelectricity. Following recent efforts on the converse flexoelectric effect in finite samples, the proposed model properly accounts for thermodynamically consistent, symmetric direct and converse coupling terms. The transverse mode flexoelectric coupling coefficient (k) is obtained analytically as a direct measure of energy conversion; its dependence on the cantilever thickness and a material Figure of Merit (FoM) is shown. Size effects are further demonstrated by simulations of the electromechanical frequency response for a Strontium Titanate (STO) energy harvester at different geometric scales. It is obtained that the flexoelectric coupling coefficient of an STO cantilever for the fundamental bending mode increases from k ≈3.5 ×10-7 to k ≈0.33 as the thickness is reduced from mm- to nm-level. A critique of the experimentally identified large flexoelectric coefficient for Barium Strontium Titanate (BST) from the literature is also given with a coupling coefficient perspective.

  5. Energy conversion during magnetic reconnection for magnetotail-like equilibria

    SciTech Connect

    Yoon, P. H.; Lui, A. T. Y.

    2006-10-15

    The principle of magnetic field-to-particle energy conversion for magnetic reconnection, originally developed by the authors for Harris-Fadeev equilibria, is extended to include a finite north-south (normal) component of the magnetic field, which is typical of the Earth's magnetotail environment. On the basis of the exact conservation laws derived from the nonlinear Vlasov equation, it is demonstrated that a small portion of the energy stored in the magnetic field is released and converted to particle thermal energy as a result of the magnetic field topological transformation, i.e., reconnection. It is also found that the normal field component has a minimal impact on the efficacy of the energy exchange.

  6. Alkali layered compounds interfaces for energy conversion and energy storage

    NASA Technical Reports Server (NTRS)

    Papageorgopoulos, Chris A.

    1996-01-01

    During year one a new ultra-high vacuum, an Ar(+) ion sputterer, a low energy electron diffraction (LEED) system, an Auger electron spectrometer (AES), a work function measurement device with a Kelvin probe, and related accessories were used. The study found a focus in the adsorption of chalcogenides on Si and III-V compound semiconductors. In the second year, a scanning tunneling microscope was obtained along with a quadrapole mass spectrometer, power supplies, a computer, a chart recorder, etc. We started the systematic study on the adsorption of chalcogenides on the compound semiconductor surfaces. The third year saw the mounting of the scanning tunneling microscope (STM) on the existing UHV system. The investigation continued with the adsorption of Cs (alkali) on S-covered Si(100)2x1 surfaces. Then the adsorption of S on Cs-covered Si(100) surfaces was studied.

  7. Experimental study of energy conversion in the magnetic reconnection layer

    NASA Astrophysics Data System (ADS)

    Yamada, Masaaki

    2014-10-01

    Magnetic reconnection, in which magnetic field lines break and reconnect to change their topology, occurs throughout the universe: in solar flares, the earth's magnetosphere, star forming galaxies, and laboratory fusion plasmas. The essential feature of reconnection is that it energizes plasma particles by converting magnetic energy to particle energy; this process both accelerates and heats the plasma particles. Despite the recent advances of reconnection research, the exact mechanisms for bulk plasma heating, particle acceleration, and energy flow channels remain unresolved. In this work, the mechanisms responsible for the energization of plasma particles in the magnetic reconnection layer are investigated in the MRX device together with a quantitative evaluation of the conversion of magnetic energy to ions and electrons. A comprehensive analysis of the reconnection layer is made in terms of two-fluid physics based on the measurements of two-dimensional profiles of 1) electric potential, 2) flow vectors of electrons and ions, and 3) the electron temperature, Te and the ion temperature, Ti in the layer. It is experimentally verified that a saddle shaped electrostatic electric potential profile is formed in the reconnection plane. Ions are accelerated across the separatrices by the strong electrostatic field and enter the exhaust region where they become thermalized. Electron heating is observed to extend beyond the electron diffusion region, and non-classical heating mechanisms associated with high frequency fluctuations is found to play a role. Our quantitative analysis of the energy transport processes and energy inventory concludes that more than 50% of magnetic energy is converted to plasma particles, of which 2/3 transferred to ions and 1/3 to electrons. The results which demonstrate that conversion of magnetic energy occurs in a significantly larger region than theoretically considered before, are compared with the two-fluid simulations and the recent space

  8. ELENA MCP detector: absolute efficiency measurement for low energy neutral atoms

    NASA Astrophysics Data System (ADS)

    Rispoli, R.; De Angelis, E.; Colasanti, L.; Vertolli, N.; Orsini, S.; Scheer, J.; Mura, A.; Milillo, A.; Wurz, P.; Selci, S.; Di Lellis, A. M.; Leoni, R.; D'Alessandro, M.; Mattioli, F.; Cibella, S.

    2012-04-01

    MicroChannel plates (MCP) detectors are frequently used in space instrumentation for detecting a wide range of radiation and particles. In particular, the capability to detect non-thermal low energy neutral species is crucial for the sensor ELENA (Emitted Low-Energy Neutral Atoms), part of the package SERENA (Search for Exospheric Refilling and Emitted Natural Abundances) on board the BepiColombo mission to Mercury to be launched in 2014. ELENA is a TOF sensor, based on a novel concept ultra-sonic oscillating shutter (Start section)which is operated at frequencies up to 50 kHz; a MCP detector is used as a Stop section. It is aimed to detect neutral atoms in the range 10 eV - 5 keV, within 70° FOV, perpendicular to the S/C orbital plane. ELENA will monitor the emission of neutral atoms from the whole surface of Mercury thanks to the spacecraft motion. The major scientific objectives are the interaction between the environment and the planet, the global particle loss-rate and the remote sensing of the surface properties. In particular, surface release processes are investigated by identifying particles release from the surface, via solar wind-induced ion sputtering (<1eV and >100 eV) as well as Hydrogen back-scattered at hundreds eV. MCP absolute detection efficiency for very low energy neutral atoms (E< 30eV) is a crucial point not yet investigated. At the MEFISTO facility of the Physical Institute of University of Bern (CH), measurements on three different type of MCPs coating have been performed providing the behaviors of MCP detection efficiency in the range 10eV-1keV. Outcomes from such measurements are here discussed.

  9. Absolute Entropy and Energy of Carbon Dioxide Using the Two-Phase Thermodynamic Model.

    PubMed

    Huang, Shao-Nung; Pascal, Tod A; Goddard, William A; Maiti, Prabal K; Lin, Shiang-Tai

    2011-06-14

    The two-phase thermodynamic (2PT) model is used to determine the absolute entropy and energy of carbon dioxide over a wide range of conditions from molecular dynamics trajectories. The 2PT method determines the thermodynamic properties by applying the proper statistical mechanical partition function to the normal modes of a fluid. The vibrational density of state (DoS), obtained from the Fourier transform of the velocity autocorrelation function, converges quickly, allowing the free energy, entropy, and other thermodynamic properties to be determined from short 20-ps MD trajectories. The anharmonic effects in the vibrations are accounted for by the broadening of the normal modes into bands from sampling the velocities over the trajectory. The low frequency diffusive modes, which lead to finite DoS at zero frequency, are accounted for by considering the DoS as a superposition of gas-phase and solid-phase components (two phases). The analytical decomposition of the DoS allows for an evaluation of properties contributed by different types of molecular motions. We show that this 2PT analysis leads to accurate predictions of entropy and energy of CO2 over a wide range of conditions (from the triple point to the critical point of both the vapor and the liquid phases along the saturation line). This allows the equation of state of CO2 to be determined, which is limited only by the accuracy of the force field. We also validated that the 2PT entropy agrees with that determined from thermodynamic integration, but 2PT requires only a fraction of the time. A complication for CO2 is that its equilibrium configuration is linear, which would have only two rotational modes, but during the dynamics it is never exactly linear, so that there is a third mode from rotational about the axis. In this work, we show how to treat such linear molecules in the 2PT framework.

  10. Nanostructured transition metal oxides for energy storage and conversion

    NASA Astrophysics Data System (ADS)

    Li, Qiang

    Lithium-ion batteries, supercapacitors and photovoltaic devices have been widely considered as the three major promising alternatives of fossil fuels facing upcoming depletion to power the 21th century. The conventional film configuration of electrochemical electrodes hardly fulfills the high energy and efficiency requirements because heavy electroactive material deposition restricts ion diffusion path, and lowers power density and fault tolerance. In this thesis, I demonstrate that novel nanoarchitectured transition metal oxides (TMOs), e.g. MnO2, V2O 5, and ZnO, and their relevant nanocomposites were designed, fabricated and assembled into devices to deliver superior electrochemical performances such as high energy and power densities, and rate capacity. These improvements could be attributed to the significant enhancement of surface area, shortened ion diffusion distances and facile penetration of electrolyte solution into open structures of networks as well as to the pseudocapacitance domination. The utilization of ForcespinningRTM, a newly developed nanofiber processing technology, for large-scale energy storage and conversion applications is emphasized. This process simplifies the tedious multi-step hybridization synthesis and facilitates the contradiction between the micro-batch production and the ease of large-scale manufacturing. Key Words: Transition metal oxides, energy storage and conversion, ForcespinningRTM, pseudocapacitance domination, high rate capacity

  11. Investigation of direct solar-to-microwave energy conversion techniques

    NASA Technical Reports Server (NTRS)

    Chatterton, N. E.; Mookherji, T. K.; Wunsch, P. K.

    1978-01-01

    Identification of alternative methods of producing microwave energy from solar radiation for purposes of directing power to the Earth from space is investigated. Specifically, methods of conversion of optical radiation into microwave radiation by the most direct means are investigated. Approaches based on demonstrated device functioning and basic phenomenologies are developed. There is no system concept developed, that is competitive with current baseline concepts. The most direct methods of conversion appear to require an initial step of production of coherent laser radiation. Other methods generally require production of electron streams for use in solid-state or cavity-oscillator systems. Further development is suggested to be worthwhile for suggested devices and on concepts utilizing a free-electron stream for the intraspace station power transport mechanism.

  12. Surface conversion techniques for low energy neutral atom imagers

    NASA Technical Reports Server (NTRS)

    Quinn, J. M.

    1995-01-01

    This investigation has focused on development of key technology elements for low energy neutral atom imaging. More specifically, we have investigated the conversion of low energy neutral atoms to negatively charged ions upon reflection from specially prepared surfaces. This 'surface conversion' technique appears to offer a unique capability of detecting, and thus imaging, neutral atoms at energies of 0.01 - 1 keV with high enough efficiencies to make practical its application to low energy neutral atom imaging in space. Such imaging offers the opportunity to obtain the first instantaneous global maps of macroscopic plasma features and their temporal variation. Through previous in situ plasma measurements, we have a statistical picture of large scale morphology and local measurements of dynamic processes. However, with in situ techniques it is impossible to characterize or understand many of the global plasma transport and energization processes. A series of global plasma images would greatly advance our understanding of these processes and would provide the context for interpreting previous and future in situ measurements. Fast neutral atoms, created from ions that are neutralized in collisions with exospheric neutrals, offer the means for remotely imaging plasma populations. Energy and mass analysis of these neutrals provides critical information about the source plasma distribution. The flux of neutral atoms available for imaging depends upon a convolution of the ambient plasma distribution with the charge exchange cross section for the background neutral population. Some of the highest signals are at relatively low energies (well below 1 keV). This energy range also includes some of the most important plasma populations to be imaged, for example the base of the cleft ion fountain.

  13. Renewable energy from corn residues by thermochemical conversion

    NASA Astrophysics Data System (ADS)

    Yu, Fei

    Declining fossil oil reserve, skyrocket price, unsecured supplies, and environment pollution are among the many energy problems we are facing today. It is our conviction that renewable energy is a solution to these problems. The long term goal of the proposed research is to develop commercially practical technologies to produce energy from renewable resources. The overall objective of my research is to study and develop thermochemical processes for converting bulky and low-energy-density biomass materials into bio-fuels and value-added bio-products. The rationale for the proposed research is that, once such processes are developed, processing facility can be set up on or near biomass product sites, reducing the costs associated with transport of bulky biomass which is a key technical barrier to biomass conversion. In my preliminary research, several conversion technologies including atmospheric pressure liquefaction, high pressure liquefaction, and microwave pyrolysis have been evaluated. Our data indicated that microwave pyrolysis had the potential to become a simple and economically viable biomass conversion technology. Microwave pyrolysis is an innovative process that provides efficient and uniform heating, and are robust to type, size and uniformity of feedstock and therefore suitable for almost any waste materials without needing to reduce the particle size. The proposed thesis focused on in-depth investigations of microwave pyrolysis of corn residues. My first specific aim was to examine the effects of processing parameters on product yields. The second specific research aim was to characterize the products (gases, bio-oils, and solid residues), which was critical to process optimization and product developments. Other research tasks included conducting kinetic modeling and preliminary mass and energy balance. This study demonstrated that microwave pyrolysis could be optimized to produce high value syngas, liquid fuels and pyrolytic carbons, and had a great

  14. Free volume hypothetical scanning molecular dynamics method for the absolute free energy of liquids

    PubMed Central

    White, Ronald P.; Meirovitch, Hagai

    2006-01-01

    The hypothetical scanning (HS) method is a general approach for calculating the absolute entropy, S, and free energy, F, by analyzing Boltzmann samples obtained by Monte Carlo (MC) or molecular dynamics (MD) techniques. With HS applied to a fluid, each configuration i of the sample is reconstructed by gradually placing the molecules in their positions at i using transition probabilities (TPs). With our recent version of HS, called HSMC-EV, each TP is calculated from MC simulations, where the simulated particles are excluded from the volume reconstructed in previous steps. In this paper we remove the excluded volume (EV) restriction, replacing it by a “free volume” (FV) approach. For liquid argon, HSMC-FV leads to an improvement in efficiency over HSMC-EV by a factor of 2–3. Importantly, the FV treatment greatly simplifies the HS implementation for liquids, allowing a much more natural application of the method for MD simulations. Given the success and popularity of MD, the present development of the HSMD method for liquids is an important advancement for HS methodology. Results for the HSMD-FV approach presented here agree well with our HSMC and thermodynamic integration results. The efficiency of HSMD-FV is equivalent to HSMC-EV. The potential use of HSMC(MD)-FV in protein systems with explicit water is discussed. PMID:16774320

  15. Absolute binding free energies for octa-acids and guests in SAMPL5

    NASA Astrophysics Data System (ADS)

    Tofoleanu, Florentina; Lee, Juyong; Pickard, Frank C., IV; König, Gerhard; Huang, Jing; Baek, Minkyung; Seok, Chaok; Brooks, Bernard R.

    2017-01-01

    As part of the SAMPL5 blind prediction challenge, we calculate the absolute binding free energies of six guest molecules to an octa-acid (OAH) and to a methylated octa-acid (OAMe). We use the double decoupling method via thermodynamic integration (TI) or Hamiltonian replica exchange in connection with the Bennett acceptance ratio (HREM-BAR). We produce the binding poses either through manual docking or by using GalaxyDock-HG, a docking software developed specifically for this study. The root mean square deviations for our most accurate predictions are 1.4 kcal mol-1 for OAH with TI and 1.9 kcal mol-1 for OAMe with HREM-BAR. Our best results for OAMe were obtained for systems with ionic concentrations corresponding to the ionic strength of the experimental solution. The most problematic system contains a halogenated guest. Our attempt to model the σ-hole of the bromine using a constrained off-site point charge, does not improve results. We use results from molecular dynamics simulations to argue that the distinct binding affinities of this guest to OAH and OAMe are due to a difference in the flexibility of the host. We believe that the results of this extensive analysis of host-guest complexes will help improve the protocol used in predicting binding affinities for larger systems, such as protein-substrate compounds.

  16. A rare gas optics-free absolute photon flux and energy analyzer to provide absolute photoionization rates of inflowing interstellar neutrals

    NASA Technical Reports Server (NTRS)

    Judge, Darrell L.

    1994-01-01

    A prototype spectrometer has been developed for space applications requiring long term absolute EUV photon flux measurements. The energy spectrum of the incoming photons is transformed directly into an electron energy spectrum by taking advantage of the photoelectric effect in one of several rare gases at low pressures. Using an electron energy spectrometer, followed by an electron multiplier detector, pulses due to individual electrons are counted. The overall efficiency of this process can be made essentially independent of gain drifts in the signal path, and the secular degradation of optical components which is often a problem in other techniques is avoided. A very important feature of this approach is its freedom from the problem of overlapping spectral orders that plagues grating EUV spectrometers. An instrument with these features has not been flown before, but is essential to further advances in our understanding of solar EUV flux dynamics, and the coupled dynamics of terrestrial and planetary atmospheres. The detailed characteristics of this optics-free spectrometer are presented in the publications section.

  17. Easy Absolute Values? Absolutely

    ERIC Educational Resources Information Center

    Taylor, Sharon E.; Mittag, Kathleen Cage

    2015-01-01

    The authors teach a problem-solving course for preservice middle-grades education majors that includes concepts dealing with absolute-value computations, equations, and inequalities. Many of these students like mathematics and plan to teach it, so they are adept at symbolic manipulations. Getting them to think differently about a concept that they…

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

    PubMed

    Kalyanasundaram, K; Graetzel, M

    2010-06-01

    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.

  19. Electrothermal energy conversion using electron gas volumetric change inside semiconductors

    NASA Astrophysics Data System (ADS)

    Yazawa, K.; Shakouri, A.

    2016-07-01

    We propose and analyze an electrothermal energy converter using volumetric changes in non-equilibrium electron gas inside semiconductors. The geometric concentration of electron gas under an electric field increases the effective pressure of the electrons, and then a barrier filters out cold electrons, acting like a valve. Nano- and micro-scale features enable hot electrons to arrive at the contact in a short enough time to avoid thermalization with the lattice. Key length and time scales, preliminary device geometry, and anticipated efficiency are estimated for electronic analogs of Otto and Brayton power generators and Joule-Thomson micro refrigerators on a chip. The power generators convert the energy of incident photons from the heat source to electrical current, and the refrigerator can reduce the temperature of electrons in a semiconductor device. The analytic calculations show that a large energy conversion efficiency or coefficient of performance may be possible.

  20. Transition Metal Nitrides for Electrocatalytic Energy Conversion: Opportunities and Challenges.

    PubMed

    Xie, Junfeng; Xie, Yi

    2016-03-07

    Electrocatalytic energy conversion has been considered as one of the most efficient and promising pathways for realizing energy storage and energy utilization in modern society. To improve electrocatalytic reactions, specific catalysts are needed to lower the overpotential. In the search for efficient alternatives to noble metal catalysts, transition metal nitrides have attracted considerable interest due to their high catalytic activity and unique electronic structure. Over the past few decades, numerous nitride-based catalysts have been explored with respect to their ability to drive various electrocatalytic reactions, such as the hydrogen evolution reaction and the oxygen evolution reaction to achieve water splitting and the oxygen reduction reaction coupled with the methanol oxidation reaction to construct fuel cells or rechargeable Li-O2 batteries. This Minireview provides a brief overview of recent progress on electrocatalysts based on transition metal nitrides, and outlines the current challenges and future opportunities.

  1. Quantum Coherence in Photosynthesis for Efficient Solar Energy Conversion

    PubMed Central

    Romero, Elisabet; Augulis, Ramunas; Novoderezhkin, Vladimir I.; Ferretti, Marco; Thieme, Jos; Zigmantas, Donatas; van Grondelle, Rienk

    2014-01-01

    The crucial step in the conversion of solar to chemical energy in Photosynthesis takes place in the reaction center where the absorbed excitation energy is converted into a stable charge separated state by ultrafast electron transfer events. However, the fundamental mechanism responsible for the near unity quantum efficiency of this process is unknown. Here we elucidate the role of coherence in determining the efficiency of charge separation in the plant photosystem II reaction centre (PSII RC) by comprehensively combining experiment (two-dimensional electronic spectroscopy) and theory (Redfield theory). We reveal the presence of electronic coherence between excitons as well as between exciton and charge transfer states which we argue to be maintained by vibrational modes. Furthermore, we present evidence for the strong correlation between the degree of electronic coherence and efficient and ultrafast charge separation. We propose that this coherent mechanism will inspire the development of new energy technologies. PMID:26870153

  2. Electrical System for Home Conversion and Storage of Solar Energy.

    PubMed

    Giacoletto, L J

    1959-10-09

    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.

  3. Calculation of the absolute free energy of a smectic-A phase

    NASA Astrophysics Data System (ADS)

    Huang, Chien-Cheng; Ramachandran, Sanoop; Ryckaert, Jean-Paul

    2014-12-01

    In this paper, we provide a scheme to compute the absolute free energy of a smectic-A phase via the "indirect method." The state of interest is connected through a three-step reversible path to a reference state. This state consists of a low-density layer of rods coupled to two external fields maintaining these rods close to the layer's plane and oriented preferably normal to the layer. The low-density free energy of the reference state can be computed on the basis of the relevant second virial coefficients between two rods coupled to the two external fields. We apply this technique to the Gay-Berne potential for calamitics with a parameter set leading to stable isotropic (I), nematic (N), smectic-A (SmA), and crystal (Cr) phases. We locate the I-SmA phase transition at low pressure and the sequence of phase transitions I-N-SmA along higher-pressure isobars and we establish the location of the I-N-SmA triple point. Close to this triple point, we show that the N-SmA transition is clearly first order. Our results are compared to the coexistence lines of the approximate phase diagram elucidated by de Miguel et al. [J. Chem. Phys. 121, 11183 (2004), 10.1063/1.1810472] established through the direct observation of the sequence of phase transitions occurring along isobars under heating or cooling sequences of runs. Finally, we discuss the potential of our technique in studying similar transitions observed on layered phases under confinement.

  4. Calculation of the absolute free energy of a smectic-A phase.

    PubMed

    Huang, Chien-Cheng; Ramachandran, Sanoop; Ryckaert, Jean-Paul

    2014-12-01

    In this paper, we provide a scheme to compute the absolute free energy of a smectic-A phase via the "indirect method." The state of interest is connected through a three-step reversible path to a reference state. This state consists of a low-density layer of rods coupled to two external fields maintaining these rods close to the layer's plane and oriented preferably normal to the layer. The low-density free energy of the reference state can be computed on the basis of the relevant second virial coefficients between two rods coupled to the two external fields. We apply this technique to the Gay-Berne potential for calamitics with a parameter set leading to stable isotropic (I), nematic (N), smectic-A (SmA), and crystal (Cr) phases. We locate the I-SmA phase transition at low pressure and the sequence of phase transitions I-N-SmA along higher-pressure isobars and we establish the location of the I-N-SmA triple point. Close to this triple point, we show that the N-SmA transition is clearly first order. Our results are compared to the coexistence lines of the approximate phase diagram elucidated by de Miguel et al. [J. Chem. Phys. 121, 11183 (2004)] established through the direct observation of the sequence of phase transitions occurring along isobars under heating or cooling sequences of runs. Finally, we discuss the potential of our technique in studying similar transitions observed on layered phases under confinement.

  5. A high-performance liquid chromatography-electronic circular dichroism online method for assessing the absolute enantiomeric excess and conversion ratio of asymmetric reactions.

    PubMed

    Zhang, Xiang; Wang, Mingchao; Li, Li; Yin, Dali

    2017-03-02

    Asymmetric reactions often need to be evaluated during the synthesis of chiral compounds. However, traditional evaluation methods require the isolation of the individual enantiomer, which is tedious and time-consuming. Thus, it is desirable to develop simple, practical online detection methods. We developed a method based on high-performance liquid chromatography-electronic circular dichroism (HPLC-ECD) that simultaneously analyzes the material conversion ratio and absolute optical purity of each enantiomer. In particular, only a reverse-phase C18 column instead of a chiral column is required in our method because the ECD measurement provides a g-factor that describes the ratio of each enantiomer in the mixtures. We used our method to analyze the asymmetric hydrosilylation of β-enamino esters, and we discussed the advantage, feasibility, and effectiveness of this new methodology.

  6. A high-performance liquid chromatography-electronic circular dichroism online method for assessing the absolute enantiomeric excess and conversion ratio of asymmetric reactions

    PubMed Central

    Zhang, Xiang; Wang, Mingchao; Li, Li; Yin, Dali

    2017-01-01

    Asymmetric reactions often need to be evaluated during the synthesis of chiral compounds. However, traditional evaluation methods require the isolation of the individual enantiomer, which is tedious and time-consuming. Thus, it is desirable to develop simple, practical online detection methods. We developed a method based on high-performance liquid chromatography-electronic circular dichroism (HPLC-ECD) that simultaneously analyzes the material conversion ratio and absolute optical purity of each enantiomer. In particular, only a reverse-phase C18 column instead of a chiral column is required in our method because the ECD measurement provides a g-factor that describes the ratio of each enantiomer in the mixtures. We used our method to analyze the asymmetric hydrosilylation of β-enamino esters, and we discussed the advantage, feasibility, and effectiveness of this new methodology. PMID:28252028

  7. A high-performance liquid chromatography-electronic circular dichroism online method for assessing the absolute enantiomeric excess and conversion ratio of asymmetric reactions

    NASA Astrophysics Data System (ADS)

    Zhang, Xiang; Wang, Mingchao; Li, Li; Yin, Dali

    2017-03-01

    Asymmetric reactions often need to be evaluated during the synthesis of chiral compounds. However, traditional evaluation methods require the isolation of the individual enantiomer, which is tedious and time-consuming. Thus, it is desirable to develop simple, practical online detection methods. We developed a method based on high-performance liquid chromatography-electronic circular dichroism (HPLC-ECD) that simultaneously analyzes the material conversion ratio and absolute optical purity of each enantiomer. In particular, only a reverse-phase C18 column instead of a chiral column is required in our method because the ECD measurement provides a g-factor that describes the ratio of each enantiomer in the mixtures. We used our method to analyze the asymmetric hydrosilylation of β-enamino esters, and we discussed the advantage, feasibility, and effectiveness of this new methodology.

  8. Explorations of Novel Energy Conversion and Storage Systems

    NASA Astrophysics Data System (ADS)

    Duffin, Andrew Mark

    At present, the majority of the world's energy demand is met by the consumption of exhaustible fuel supplies. Consequently, it is urgent to research and develop viable alternatives. In this dissertation, I present research that addresses fundamental questions concerning how water interacts with surfaces and solutes, with the goal of identifying novel systems for energy production and storage. Electrokinetic currents are created when moving fluid entrains charge from the diffuse portion of an electric double layer and carries that charge downstream. The potential difference that develops on either end of the channel is known as the streaming potential. Chapter 2 of this dissertation focuses on electrokinetic energy production and conversion efficiency of liquid microjets. Section 1 of Chapter 2 presents proof-of-principle research demonstrating that molecular hydrogen is generated from electrokinetic currents in liquid water microjets. Hydrogen is generated when hydrated protons are preferentially carried downstream and recombine with electrons at a grounded target electrode. Both the current and hydrogen production scale nearly quadratically with flow rate, as predicted by equations derived from simple double layer theory and fluid mechanics. The efficiency is currently very low (ca 10-6) and is limited by the low electrokinetic current (˜nA). Designs to improve this efficiency are considered. Rather than chemical conversion efficiency, Section 2 of Chapter 2 investigates the electrical conversion efficiency of liquid water microjets. Typical electrokinetic energy conversion schemes measure current or voltage via electrodes in the fluid reservoirs on either side of a channel. With this design, the streaming potential drives a current against the flow of the fluid and, consequently, limits the conversion efficiency. In contrast, liquid microjets break up into droplets before reaching the downstream electrode and this eliminates the possibility for back conduction

  9. Visible light to electrical energy conversion using photoelectrochemical cells

    NASA Technical Reports Server (NTRS)

    Wrighton, Mark S. (Inventor); Ellis, Arthur B. (Inventor); Kaiser, Steven W. (Inventor)

    1983-01-01

    Sustained conversion of low energy visible or near i.r. light (>1.25 eV) to electrical energy has been obtained using wet photoelectrochemical cells where there are no net chemical changes in the system. Stabilization of n-type semi-conductor anodes of CdS, CdSe, CdTe, GaP, GaAs and InP to photoanodic dissolution is achieved by employing selected alkaline solutions of Na.sub.2 S, Na.sub.2 S/S, Na.sub.2 Se, Na.sub.2 Se/Se, Na.sub.2 Te and Na.sub.2 Te/Te as the electrolyte. The oxidation of (poly) sulfide, (poly)selenide or (poly)telluride species occurs at the irradiated anode, and reduction of polysulfide, polyselenide or polytelluride species occurs at the dark Pt cathode of the photoelectrochemical cell. Optical to electrical energy conversion efficiencies approaching 15% at selected frequencies have been observed in some cells. The wavelength for the onset of photocurrent corresponds to the band gap of the particular anode material used in the cell.

  10. Nanostructured Solar Irradiation Control Materials for Solar Energy Conversion

    NASA Technical Reports Server (NTRS)

    Kang, Jinho; Marshall, I. A.; Torrico, M. N.; Taylor, C. R.; Ely, Jeffry; Henderson, Angel Z.; Kim, J.-W.; Sauti, G.; Gibbons, L. J.; Park, C.; Lowther, S. E.; Lillehei, P. T.; Bryant, R. G.

    2012-01-01

    Tailoring the solar absorptivity (alpha(sub s)) and thermal emissivity (epsilon(sub T)) of materials constitutes an innovative approach to solar energy control and energy conversion. Numerous ceramic and metallic materials are currently available for solar absorbance/thermal emittance control. However, conventional metal oxides and dielectric/metal/dielectric multi-coatings have limited utility due to residual shear stresses resulting from the different coefficient of thermal expansion of the layered materials. This research presents an alternate approach based on nanoparticle-filled polymers to afford mechanically durable solar-absorptive and thermally-emissive polymer nanocomposites. The alpha(sub s) and epsilon(sub T) were measured with various nano inclusions, such as carbon nanophase particles (CNPs), at different concentrations. Research has shown that adding only 5 wt% CNPs increased the alpha(sub s) and epsilon(sub T) by a factor of about 47 and 2, respectively, compared to the pristine polymer. The effect of solar irradiation control of the nanocomposite on solar energy conversion was studied. The solar irradiation control coatings increased the power generation of solar thermoelectric cells by more than 380% compared to that of a control power cell without solar irradiation control coatings.

  11. Physical aspects of ferroelectric semiconductors for photovoltaic solar energy conversion

    NASA Astrophysics Data System (ADS)

    Lopez-Varo, Pilar; Bertoluzzi, Luca; Bisquert, Juan; Alexe, Marin; Coll, Mariona; Huang, Jinsong; Jimenez-Tejada, Juan Antonio; Kirchartz, Thomas; Nechache, Riad; Rosei, Federico; Yuan, Yongbo

    2016-10-01

    Solar energy conversion using semiconductors to fabricate photovoltaic devices relies on efficient light absorption, charge separation of electron-hole pair carriers or excitons, and fast transport and charge extraction to counter recombination processes. Ferroelectric materials are able to host a permanent electrical polarization which provides control over electrical field distribution in bulk and interfacial regions. In this review, we provide a critical overview of the physical principles and mechanisms of solar energy conversion using ferroelectric semiconductors and contact layers, as well as the main achievements reported so far. In a ferroelectric semiconductor film with ideal contacts, the polarization charge would be totally screened by the metal layers and no charge collection field would exist. However, real materials show a depolarization field, smooth termination of polarization, and interfacial energy barriers that do provide the control of interface and bulk electric field by switchable spontaneous polarization. We explore different phenomena as the polarization-modulated Schottky-like barriers at metal/ferroelectric interfaces, depolarization fields, vacancy migration, and the switchable rectifying behavior of ferroelectric thin films. Using a basic physical model of a solar cell, our analysis provides a general picture of the influence of ferroelectric effects on the actual power conversion efficiency of the solar cell device, and we are able to assess whether these effects or their combinations are beneficial or counterproductive. We describe in detail the bulk photovoltaic effect and the contact layers that modify the built-in field and the charge injection and separation in bulk heterojunction organic cells as well as in photocatalytic and water splitting devices. We also review the dominant families of ferroelectric materials that have been most extensively investigated and have provided the best photovoltaic performance.

  12. Advanced solar energy conversion. [solar pumped gas lasers

    NASA Technical Reports Server (NTRS)

    Lee, J. H.

    1981-01-01

    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.

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

    SciTech Connect

    Green, H.J. ); Guenther, P.R. )

    1990-09-01

    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.

  14. Novel silicon phases and nanostructures for solar energy conversion

    NASA Astrophysics Data System (ADS)

    Wippermann, Stefan; He, Yuping; Vörös, Márton; Galli, Giulia

    2016-12-01

    Silicon exhibits a large variety of different bulk phases, allotropes, and composite structures, such as, e.g., clathrates or nanostructures, at both higher and lower densities compared with diamond-like Si-I. New Si structures continue to be discovered. These novel forms of Si offer exciting prospects to create Si based materials, which are non-toxic and earth-abundant, with properties tailored precisely towards specific applications. We illustrate how such novel Si based materials either in the bulk or as nanostructures may be used to significantly improve the efficiency of solar energy conversion devices.

  15. Method and apparatus for testing electrochemical energy conversion devices

    NASA Technical Reports Server (NTRS)

    Cisar, Alan J. (Inventor); Murphy, Oliver J. (Inventor)

    1996-01-01

    A system for testing electrochemical energy conversion and storage devices includes means for sensing the current from the storage device and varying the load across the storage device in response to the current sensed. The system is equally adaptable to batteries and fuel cells. Means is also provided to sense system parameters from a plurality of locations within the system. Certain parameters are then stored in digital form for archive purposes and certain other parameters are used to develop control signals in a host processor.

  16. Low cost composite materials for wind energy conversion systems

    NASA Technical Reports Server (NTRS)

    Weingart, O.

    1980-01-01

    A winding process utilizing a low-cost E-glass fabric called transverse-filament tape for low-cost production of wind turbine generators (WTG) is described. The process can be carried out continuously at high speed to produce large one-piece parts with tapered wall thicknesses on a tapered mandrel. It is being used to manufacture blades for the NASA/DOE 200-ft-diameter MOD-1 WTG and Rockwell/DOE 40-kW small wind energy conversion system (SWECS).

  17. Dimensional Analysis of Ocean Thermal Energy Conversion Heat Exchangers

    DTIC Science & Technology

    1977-06-30

    8217thIJt4IiTY CLASSIFICATION OF TWI4S PAG(E ona Dola t ern.r) 20. (continued) c-a• of factors having significance in OTEC (Ocean Thermal Energy Conversion...heat exchangers. Certain of these groups are then evaluated for a model and prototype OTEC -Type heat exchanger using the same working fluid and ex...Development Administration, and the U. S. Navy are brought out. Chapter II investigates the scaling problems of heat ex- changers in OTEC (Ocean Thermal

  18. Heat transfer research for ocean thermal energy conversion

    SciTech Connect

    Kreith, F.; Bharathan, D.

    1988-02-01

    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.

  19. Heat transfer research for ocean thermal energy conversion

    NASA Astrophysics Data System (ADS)

    Kreith, F.; Bharathan, D.

    1987-03-01

    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.

  20. Low cost composite materials for wind energy conversion systems

    NASA Astrophysics Data System (ADS)

    Weingart, O.

    1980-06-01

    A winding process utilizing a low-cost E-glass fabric called transverse-filament tape for low-cost production of wind turbine generators (WTG) is described. The process can be carried out continuously at high speed to produce large one-piece parts with tapered wall thicknesses on a tapered mandrel. It is being used to manufacture blades for the NASA/DOE 200-ft-diameter MOD-1 WTG and Rockwell/DOE 40-kW small wind energy conversion system (SWECS).

  1. Analysis of dynamic effects in solar thermal energy conversion systems

    NASA Technical Reports Server (NTRS)

    Hamilton, C. L.

    1978-01-01

    The paper examines a study the purpose of which is to assess the performance of solar thermal power systems insofar as it depends on the dynamic character of system components and the solar radiation which drives them. Using a dynamic model, the daily operation of two conceptual solar conversion systems was simulated under varying operating strategies and several different time-dependent radiation intensity functions. These curves ranged from smoothly varying input of several magnitudes to input of constant total energy whose intensity oscillated with periods from 1/4 hour to 6 hours.

  2. Advanced nanostructured materials for energy storage and conversion

    NASA Astrophysics Data System (ADS)

    Hutchings, Gregory S.

    Due to a global effort to reduce greenhouse gas emissions and to utilize renewable sources of energy, much effort has been directed towards creating new alternatives to fossil fuels. Identifying novel materials for energy storage and conversion can enable radical changes to the current fuel production infrastructure and energy utilization. The use of engineered nanostructured materials in these systems unlocks unique catalytic activity in practical configurations. In this work, research efforts have been focused on the development of nanostructured materials to address the need for both better energy conversion and storage, with applications toward Li-O2 battery electrocatalysts, electrocatalytic generation of H2, conversion of furfural to useful chemicals and fuels, and Li battery anode materials. Highly-active alpha-MnO2 materials were synthesized for use as bifunctional oxygen reduction (ORR) and evolution (OER) catalysts in Li-O2 batteries, and were evaluated under operating conditions with a novel in situ X-ray absorption spectroscopy configuration. Through detailed analysis of local coordination and oxidation states of Mn atoms at key points in the electrochemical cycle, a self-switching behavior affecting the bifunctional activity was identified and found to be critical. In an additional study of materials for lithium batteries, nanostructured TiO2 anode materials doped with first-row transition metals were synthesized and evaluated for improving battery discharge capacity and rate performance, with Ni and Co doping at low levels found to cause the greatest enhancement. In addition to battery technology research, I have also sought to find inexpensive and earth-abundant electrocatalysts to replace state-of-the-art Pt/C in the hydrogen evolution reaction (HER), a systematic computational study of Cu-based bimetallic electrocatalysts was performed. During the screening of dilute surface alloys of Cu mixed with other first-row transition metals, materials with

  3. Energy and data conversion circuits for low power sensory systems

    NASA Astrophysics Data System (ADS)

    Ghosh, Suvradip

    This dissertation focuses on the problem of increasing the lifetime of wireless sensors. This problem is addressed from two different angles: energy harvesting and data compression. Energy harvesting enables a sensor to extract energy from its environment and use it to power itself or recharge its batteries. Data compression, on the other hand, allows a sensor to save energy by reducing the radio transmission bandwidth. This dissertation proposes a fractal-based photodiode fabricated on standard CMOS process as an energy harvesting device with increased efficiency. Experiments show that, the fractal based photodiodes are 6% more efficient compared to the conventional square shaped photodiode. The fractal shape photodiode has more perimeter-to-area ratio which increases the lateral response, improving its efficiency. With increased efficiency, more current is generated but the open-circuit voltage still remains low (0.3V--0.45V depending on illumination condition). These voltages have to be boosted up to higher values if they are going to be used to power up any sensory circuit or recharge a battery. We propose a switched-inductor DC-DC converter to boost the low voltage of the photodiodes to higher voltages. The proposed circuit uses two on-chip switches and two off-chip Components: an inductor and a capacitor. Experiments show a voltage up to 2.81V can be generated from a single photodiode of 1mm2 area. The voltage booster circuit achieved a conversion efficiency of 59%. Data compression was also explored in an effort to reduce energy consumption during radio transmission. An analog-to-digital converter (ADC), which can jointly perform the tasks of digital conversion and entropy encoding, has also been proposed in this dissertation. The joint data conversion/compression help savings in area and power resources, making it suitable for on-sensor compression. The proposed converter combines a cyclic converter architecture and Golomb-Rice entropy encoder. The

  4. Absolute Calibration of Image Plate for electrons at energy between 100 keV and 4 MeV

    SciTech Connect

    Chen, H; Back, N L; Eder, D C; Ping, Y; Song, P M; Throop, A

    2007-12-10

    The authors measured the absolute response of image plate (Fuji BAS SR2040) for electrons at energies between 100 keV to 4 MeV using an electron spectrometer. The electron source was produced from a short pulse laser irradiated on the solid density targets. This paper presents the calibration results of image plate Photon Stimulated Luminescence PSL per electrons at this energy range. The Monte Carlo radiation transport code MCNPX results are also presented for three representative incident angles onto the image plates and corresponding electron energies depositions at these angles. These provide a complete set of tools that allows extraction of the absolute calibration to other spectrometer setting at this electron energy range.

  5. Holey tungsten oxynitride nanowires: novel anodes efficiently integrate microbial chemical energy conversion and electrochemical energy storage.

    PubMed

    Yu, Minghao; Han, Yi; Cheng, Xinyu; Hu, Le; Zeng, Yinxiang; Chen, Meiqiong; Cheng, Faliang; Lu, Xihong; Tong, Yexiang

    2015-05-20

    Holey tungsten oxynitride nanowires with superior conductivity, good biocompatibility, and good stability achieve excellent performance as anodes for both asymmetric supercapacitors and microbial fuel cells. Moreover, an innovative system is devised based on these as-prepared tungsten oxynitride anodes, which can simultaneously realize both energy conversion from chemical to electric energy and its storage.

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

    SciTech Connect

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

    2012-01-01

    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

  7. Organic electronics on fibers for energy conversion applications

    NASA Astrophysics Data System (ADS)

    O'Connor, Brendan T.

    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.

  8. Solid State Energy Conversion Alliance 2nd Annual Workshop Proceedings

    SciTech Connect

    National Energy Technology Laboratory

    2001-03-30

    The National Energy Technology Laboratory (NETL) and the Pacific Northwest National Laboratory (PNNL) are pleased to provide the proceedings of the second annual Solid State Energy Conversion Alliance (SECA) Workshop held on March 29-30, 2001 in Arlington. The package includes the presentations made during the workshop, a list of participants, and the results of the breakout sessions. Those sessions covered stack materials and processes, power electronics, balance of plant and thermal integration, fuel processing technologies, and stack and system performance modeling. The breakout sessions have been reported as accurately as possible; however, due to the recording and transcription process errors may have occurred. If you note any significant omissions or wish to provide additional information, we welcome your comments and hope that all stakeholder groups will use the enclosed information in their planning endeavors.

  9. Silicon nanowires for biosensing, energy storage, and conversion.

    PubMed

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

    2013-10-04

    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.

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

    NASA Astrophysics Data System (ADS)

    1988-03-01

    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.

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

    NASA Technical Reports Server (NTRS)

    1988-01-01

    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.

  12. OCEAN THERMAL ENERGY CONVERSION: AN OVERALL ENVIRONMENTAL ASSESSMENT

    SciTech Connect

    Sands, M. Dale

    1980-08-01

    Significant acccrmplishments in Ocean Thermal Energy Conversion (OTEC) technology have increased the probability of producing OTEC-derived power within this decade with subsequent large scale commercialization following by the turn of the century. Under U.S. Department of Energy funding, the Oceanic Engineering Operations of Interstate Electronics Corporation has prepared several OTEC Environmental Assessments over the past years, in particular, the OTEC Programmatic Environmental Assessment. The Programmatic EA considers several technological designs (open- and closed-cycle), plant configuratlons (land-based, moored, and plant-ship), and power usages (baseload electricity, ammonia and aluminum production). Potential environmental impacts, health and safetv issues and a status update of the institutional issues as they influence OTEC deployments, are included.

  13. Controlled cellular energy conversion in brown adipose tissue thermogenesis

    NASA Technical Reports Server (NTRS)

    Horowitz, J. M.; Plant, R. E.

    1978-01-01

    Brown adipose tissue serves as a model system for nonshivering thermogenesis (NST) since a) it has as a primary physiological function the conversion of chemical energy to heat; and b) preliminary data from other tissues involved in NST (e.g., muscle) indicate that parallel mechanisms may be involved. Now that biochemical pathways have been proposed for brown fat thermogenesis, cellular models consistent with a thermodynamic representation can be formulated. Stated concisely, the thermogenic mechanism in a brown fat cell can be considered as an energy converter involving a sequence of cellular events controlled by signals over the autonomic nervous system. A thermodynamic description for NST is developed in terms of a nonisothermal system under steady-state conditions using network thermodynamics. Pathways simulated include mitochondrial ATP synthesis, a Na+/K+ membrane pump, and ionic diffusion through the adipocyte membrane.

  14. Design requirements for interfaces in solar energy conversion technologies

    NASA Astrophysics Data System (ADS)

    Butler, B. L.

    1982-04-01

    Candidate materials for improving the durability and economics of solar energy conversion systems (SECS) are reviewed. A 30-yr lifetime is regarded as necessary for solar collector and concentrator materials in order to offset the high initial costs of SECS in parabolic dish, heliostat, parabolic trough, flat plate collector, OTEC, solar cell, and wind turbine configurations. The materials are required to transfer a maximum amount of intercepted energy without degrading from exposure to UV radiation, wind, water, dust, and temperature cycling. Glass and mirrored surfaces for reflecting or refracting optical subsystems are currently made from soda-lime, boro- and aluminosilicate, and must resist chemicals, abrasion, and permeability, and have good strength, flexibility, coefficient of expansion, and Young's modulus. Additional concerns are present in photochemical, solar cell, and in substrata components and systems.

  15. Performance optimization of a pneumatic wave energy conversion device

    NASA Astrophysics Data System (ADS)

    Surko, S. W.

    1982-08-01

    The purpose of this study was, for the first time, to optimize the performance of a pneumatic wave energy conversion device. The experiments of Jolly and Newmaster (1979) and Trop and Casey (1980) left a capture chamber and turbine for further investigation. To optimize the system performance the turbine had to be first analyzed so that its power performance curves could be determined. These curves were needed to help define the possible overall performance of the system, and for the impedance matching of the system necessary for performance optimization. With this knowledge, an appropriate generator was purchased and a generator-turbine linkage designed and built. The completed system was then analyzed in the 380 ft wave tank at the U.S. Naval Academy to establish its optimum performance. From the research it is clear that pneumatic wave energy conversion is a promising concept. With several hundred of these devices situated some 100 km off the coast of the Pacific Northwest each device would be producing from 50 to 200 kW which would be transferred back to shore.

  16. Energy conversion approaches and materials for high-efficiency photovoltaics

    NASA Astrophysics Data System (ADS)

    Green, Martin A.; Bremner, Stephen P.

    2017-01-01

    The past five years have seen significant cost reductions in photovoltaics and a correspondingly strong increase in uptake, with photovoltaics now positioned to provide one of the lowest-cost options for future electricity generation. What is becoming clear as the industry develops is that area-related costs, such as costs of encapsulation and field-installation, are increasingly important components of the total costs of photovoltaic electricity generation, with this trend expected to continue. Improved energy-conversion efficiency directly reduces such costs, with increased manufacturing volume likely to drive down the additional costs associated with implementing higher efficiencies. This suggests the industry will evolve beyond the standard single-junction solar cells that currently dominate commercial production, where energy-conversion efficiencies are fundamentally constrained by Shockley-Queisser limits to practical values below 30%. This Review assesses the overall prospects for a range of approaches that can potentially exceed these limits, based on ultimate efficiency prospects, material requirements and developmental outlook.

  17. Hybrid acoustic energy harvesting using combined electromagnetic and piezoelectric conversion

    NASA Astrophysics Data System (ADS)

    Khan, Farid Ullah; Izhar

    2016-02-01

    This paper reports a novel hybrid acoustic energy harvester. The harvester utilizes both the electromagnetic and piezoelectric conversion mechanisms simultaneously to convert the ambient acoustical noise into electrical power for self-powered wireless sensor nodes. The proposed harvester is comprised of a Helmholtz resonator, two magnets mounted on a piezoelectric plate, and a wound coil located under the magnets. The harvester is characterized both under harmonic and real random acoustical excitations. In-lab, under harmonic acoustical excitation at a sound pressure level of 130 dB and frequency of 2.1 kHz, an optimum power of 2.86 μW (at 114 Ω optimum load) is obtained from electromagnetic conversion and 50 μW (at 1000 Ω optimum load) is generated by the piezoelectric harvester's part. Moreover, in real acoustical environment of a domestic electric generator the peak voltages of 40 and 123 mV are produced by the electromagnetic and piezoelectric portions of the acoustic energy harvester.

  18. Plasmadynamics and ionization kinetics of thermionic energy conversion

    SciTech Connect

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

    1982-02-01

    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)

  19. Proceedings of the Chornobyl phytoremediation and biomass energy conversion workshop

    SciTech Connect

    Hartley, J.; Tokarevsky, V.

    1998-06-01

    Many concepts, systems, technical approaches, technologies, ideas, agreements, and disagreements were vigorously discussed during the course of the 2-day workshop. The workshop was successful in generating intensive discussions on the merits of the proposed concept that includes removal of radionuclides by plants and trees (phytoremediation) to clean up soil in the Chornobyl Exclusion Zone (CEZ), use of the resultant biomass (plants and trees) to generate electrical power, and incorporation of ash in concrete casks to be used as storage containers in a licensed repository for low-level waste. Twelve years after the Chornobyl Nuclear Power Plant (ChNPP) Unit 4 accident, which occurred on April 26, 1986, the primary 4radioactive contamination of concern is from radioactive cesium ({sup 137}Cs) and strontium ({sup 90}Sr). The {sup 137}Cs and {sup 90}Sr were widely distributed throughout the CEZ. The attendees from Ukraine, Russia, Belarus, Denmark and the US provided information, discussed and debated the following issues considerably: distribution and characteristics of radionuclides in CEZ; efficacy of using trees and plants to extract radioactive cesium (Cs) and strontium (Sr) from contaminated soil; selection of energy conversion systems and technologies; necessary infrastructure for biomass harvesting, handling, transportation, and energy conversion; radioactive ash and emission management; occupational health and safety concerns for the personnel involved in this work; and economics. The attendees concluded that the overall concept has technical and possibly economic merits. However, many issues (technical, economic, risk) remain to be resolved before a viable commercial-scale implementation could take place.

  20. Energy conversion approaches and materials for high-efficiency photovoltaics.

    PubMed

    Green, Martin A; Bremner, Stephen P

    2016-12-20

    The past five years have seen significant cost reductions in photovoltaics and a correspondingly strong increase in uptake, with photovoltaics now positioned to provide one of the lowest-cost options for future electricity generation. What is becoming clear as the industry develops is that area-related costs, such as costs of encapsulation and field-installation, are increasingly important components of the total costs of photovoltaic electricity generation, with this trend expected to continue. Improved energy-conversion efficiency directly reduces such costs, with increased manufacturing volume likely to drive down the additional costs associated with implementing higher efficiencies. This suggests the industry will evolve beyond the standard single-junction solar cells that currently dominate commercial production, where energy-conversion efficiencies are fundamentally constrained by Shockley-Queisser limits to practical values below 30%. This Review assesses the overall prospects for a range of approaches that can potentially exceed these limits, based on ultimate efficiency prospects, material requirements and developmental outlook.

  1. Wind Energy Conversion by Plant-Inspired Designs.

    PubMed

    McCloskey, Michael A; Mosher, Curtis L; Henderson, Eric R

    2017-01-01

    In 2008 the U.S. Department of Energy set a target of 20% wind energy by 2030. To date, induction-based turbines form the mainstay of this effort, but turbines are noisy, perceived as unattractive, a potential hazard to bats and birds, and their height hampers deployment in residential settings. Several groups have proposed that artificial plants containing piezoelectric elements may harvest wind energy sufficient to contribute to a carbon-neutral energy economy. Here we measured energy conversion by cottonwood-inspired piezoelectric leaves, and by a "vertical flapping stalk"-the most efficient piezo-leaf previously reported. We emulated cottonwood for its unusually ordered, periodic flutter, properties conducive to piezo excitation. Integrated over 0°-90° (azimuthal) of incident airflow, cottonwood mimics outperformed the vertical flapping stalk, but they produced < daW per conceptualized tree. In contrast, a modest-sized cottonwood tree may dissipate ~ 80 W via leaf motion alone. A major limitation of piezo-transduction is charge generation, which scales with capacitance (area). We thus tested a rudimentary, cattail-inspired leaf with stacked elements wired in parallel. Power increased systematically with capacitance as expected, but extrapolation to acre-sized assemblages predicts < daW. Although our results suggest that present piezoelectric materials will not harvest mid-range power from botanic mimics of convenient size, recent developments in electrostriction and triboelectric systems may offer more fertile ground to further explore this concept.

  2. Wind Energy Conversion by Plant-Inspired Designs

    PubMed Central

    Mosher, Curtis L.; Henderson, Eric R.

    2017-01-01

    In 2008 the U.S. Department of Energy set a target of 20% wind energy by 2030. To date, induction-based turbines form the mainstay of this effort, but turbines are noisy, perceived as unattractive, a potential hazard to bats and birds, and their height hampers deployment in residential settings. Several groups have proposed that artificial plants containing piezoelectric elements may harvest wind energy sufficient to contribute to a carbon-neutral energy economy. Here we measured energy conversion by cottonwood-inspired piezoelectric leaves, and by a “vertical flapping stalk”—the most efficient piezo-leaf previously reported. We emulated cottonwood for its unusually ordered, periodic flutter, properties conducive to piezo excitation. Integrated over 0°–90° (azimuthal) of incident airflow, cottonwood mimics outperformed the vertical flapping stalk, but they produced << daW per conceptualized tree. In contrast, a modest-sized cottonwood tree may dissipate ~ 80 W via leaf motion alone. A major limitation of piezo-transduction is charge generation, which scales with capacitance (area). We thus tested a rudimentary, cattail-inspired leaf with stacked elements wired in parallel. Power increased systematically with capacitance as expected, but extrapolation to acre-sized assemblages predicts << daW. Although our results suggest that present piezoelectric materials will not harvest mid-range power from botanic mimics of convenient size, recent developments in electrostriction and triboelectric systems may offer more fertile ground to further explore this concept. PMID:28085933

  3. Absolute cross sections for electronic excitations of cytosine by low energy electron impact

    PubMed Central

    Bazin, M.; Michaud, M.; Sanche, L.

    2013-01-01

    The absolute cross sections (CS) for electronic excitations of cytosine by electron impact between 5 and 18 eV were measured by electron-energy loss (EEL) spectroscopy of the molecule deposited at low coverage on an inert Ar substrate. The lowest EEL features found at 3.55 and 4.02 eV are ascribed to transitions from the ground state to the two lowest triplet 1 3A′(π→π*) and 2 3A′(π→π*) valence states of the molecule. Their energy dependent CS exhibit essentially a common maximum at about 6 eV with a value of 1.84 × 10−17 cm2 for the former and 4.94 × 10−17 cm2 for the latter. In contrast, the CS for the next EEL feature at 4.65 eV, which is ascribed to the optically allowed transition to the 2 1A′(π→π*) valence state, shows only a steep rise to about 1.04 × 10−16 cm2 followed by a monotonous decrease with the incident electron energy. The higher EEL features at 5.39, 6.18, 6.83, and 7.55 eV are assigned to the excitations of the 3 3, 1A′(π→π*), 4 1A′(π→π*), 5 1A′(π→π*), and 6 1A′(π→π*) valence states, respectively. The CS for the 3 3, 1A′ and 4 1A′ states exhibit a common enhancement at about 10 eV superimposed on a more or less a steep rise, reaching respectively a maximum of 1.27 and 1.79 × 10−16 cm2, followed by a monotonous decrease. This latter enhancement and the maximum seen at about 6 eV in the lowest triplet states correspond to the core-excited electron resonances that have been found by dissociative electron attachment experiments with cytosine in the gas phase. The weak EEL feature found at 5.01 eV with a maximum CS of 3.8 × 10−18 cm2 near its excitation threshold is attributed to transitions from the ground state to the 1 3, 1A″(n→π*) states. The monotonous rise of the EEL signal above 8 eV is attributed to the ionization of the molecule. It is partitioned into four excitation energy regions at about 8.55, 9.21, 9.83, and 11.53 eV, which correspond closely to the ionization energies of

  4. Polymerization efficiency of curing lamps: a universal energy conversion relationship predictive of conversion of resin-based composite.

    PubMed

    Halvorson, Rolf H; Erickson, Robert L; Davidson, Carel L

    2004-01-01

    A universal energy-conversion relationship (ECRu) predictive of conversion of a resin-based composite (RBC) polymerized with any light source has been described. This relationship was derived from an energy conversion relationship for RBC polymerized with a tungsten-halogen lamp and the lamp's efficiency relative to a hypothetical standard lamp. The ECRu was then used to predict conversion throughout RBC polymerized with an LED lamp using the lamp's relative efficiency compared to the standard lamp. The universal energy scale has also been described as predictive of scrape-back lengths for this RBC family when polymerized with any light source. Despite a 31% greater relative efficiency, scrape-back lengths from RBC polymerized using the LED lamp were predicted to be only 6% greater than those polymerized with the tungsten-halogen lamp when RBC is polymerized on an equal energy basis. This result was experimentally verified.

  5. Hot Carrier-Based Near-Field Thermophotovoltaic Energy Conversion.

    PubMed

    St-Gelais, Raphael; Bhatt, Gaurang Ravindra; Zhu, Linxiao; Fan, Shanhui; Lipson, Michal

    2017-03-28

    Near-field thermophotovoltaics (NFTPV) is a promising approach for direct conversion of heat to electrical power. This technology relies on the drastic enhancement of radiative heat transfer (compared to conventional blackbody radiation) that occurs when objects at different temperatures are brought to deep subwavelength distances (typically <100 nm) from each other. Achieving such radiative heat transfer between a hot object and a photovoltaic (PV) cell could allow direct conversion of heat to electricity with a greater efficiency than using current solid-state technologies (e.g., thermoelectric generators). One of the main challenges in the development of this technology, however, is its incompatibility with conventional silicon PV cells. Thermal radiation is weak at frequencies larger than the ∼1.1 eV bandgap of silicon, such that PV cells with lower excitation energies (typically 0.4-0.6 eV) are required for NFTPV. Using low bandgap III-V semiconductors to circumvent this limitation, as proposed in most theoretical works, is challenging and therefore has never been achieved experimentally. In this work, we show that hot carrier PV cells based on Schottky junctions between silicon and metallic films could provide an attractive solution for achieving high efficiency NFTPV electricity generation. Hot carrier science is currently an important field of research and several approaches are investigated for increasing the quantum efficiency (QE) of hot carrier generation beyond conventional Fowler model predictions. If the Fowler limit can indeed be overcome, we show that hot carrier-based NFTPV systems-after optimization of their thermal radiation spectrum-could allow electricity generation with up to 10-30% conversion efficiencies and 10-500 W/cm(2) generated power densities (at 900-1500 K temperatures). We also discuss how the unique properties of thermal radiation in the extreme near-field are especially well suited for investigating recently proposed approaches

  6. ECUT (Energy Conversion and Utilization Technologies Program). Biocatalysis Project

    NASA Technical Reports Server (NTRS)

    1986-01-01

    Presented are the FY 1985 accomplishments, activities, and planned research efforts of the Biocatalysis Project of the U.S. Department of Energy, Energy Conversion and Utilization Technologies (ECUT) Program. The Project's technical activities were organized as follows: In the Molecular Modeling and Applied Genetics work element, research focused on (1) modeling and simulation studies to establish the physiological basis of high temperature tolerance in a selected enzyme and the catalytic mechanisms of three species of another enzyme, and (2) determining the degree of plasmid amplification and stability of several DNA bacterial strains. In the Bioprocess Engineering work element, research focused on (1) studies of plasmid propagation and the generation of models, (2) developing methods for preparing immobilized biocatalyst beads, and (3) developing an enzyme encapsulation method. In the Process Design and Analysis work element, research focused on (1) further refinement of a test case simulation of the economics and energy efficiency of alternative biocatalyzed production processes, (2) developing a candidate bioprocess to determine the potential for reduced energy consumption and facility/operating costs, and (3) a techno-economic assessment of potential advancements in microbial ammonia production.

  7. ECUT (Energy Conversion and Utilization Technologies Program). Biocatalysis Project

    NASA Astrophysics Data System (ADS)

    1986-07-01

    Presented are the FY 1985 accomplishments, activities, and planned research efforts of the Biocatalysis Project of the U.S. Department of Energy, Energy Conversion and Utilization Technologies (ECUT) Program. The Project's technical activities were organized as follows: In the Molecular Modeling and Applied Genetics work element, research focused on (1) modeling and simulation studies to establish the physiological basis of high temperature tolerance in a selected enzyme and the catalytic mechanisms of three species of another enzyme, and (2) determining the degree of plasmid amplification and stability of several DNA bacterial strains. In the Bioprocess Engineering work element, research focused on (1) studies of plasmid propagation and the generation of models, (2) developing methods for preparing immobilized biocatalyst beads, and (3) developing an enzyme encapsulation method. In the Process Design and Analysis work element, research focused on (1) further refinement of a test case simulation of the economics and energy efficiency of alternative biocatalyzed production processes, (2) developing a candidate bioprocess to determine the potential for reduced energy consumption and facility/operating costs, and (3) a techno-economic assessment of potential advancements in microbial ammonia production.

  8. Using Delft3D to Simulate Current Energy Conversion

    NASA Astrophysics Data System (ADS)

    James, S. C.; Chartrand, C.; Roberts, J.

    2015-12-01

    As public concern with renewable energy increases, current energy conversion (CEC) technology is being developed to optimize energy output and minimize environmental impact. CEC turbines generate energy from tidal and current systems and create wakes that interact with turbines located downstream of a device. The placement of devices can greatly influence power generation and structural reliability. CECs can also alter the ecosystem process surrounding the turbines, such as flow regimes, sediment dynamics, and water quality. Software is needed to investigate specific CEC sites to simulate power generation and hydrodynamic responses of a flow through a CEC turbine array. This work validates Delft3D against several flume experiments by simulating the power generation and hydrodynamic response of flow through a turbine or actuator disc(s). Model parameters are then calibrated against these data sets to reproduce momentum removal and wake recovery data with 3-D flow simulations. Simulated wake profiles and turbulence intensities compare favorably to the experimental data and demonstrate the utility and accuracy of a fast-running tool for future siting and analysis of CEC arrays in complex domains.

  9. Bio-inspired Approaches to Solar Energy Conversion

    NASA Astrophysics Data System (ADS)

    Wasielewski, Michael

    2012-02-01

    Natural photosynthesis is carried out by organized assemblies of photofunctional tetrapyrrole chromophores and catalysts within proteins that provide specifically tailored environments to optimize solar energy conversion. Artificial photosynthetic systems for practical solar fuels production must collect light energy, separate charge, and transport charge to catalytic sites where multi-electron redox processes will occur. The primary goal of our research in this field is to understand the fundamental principles needed to develop integrated artificial photosynthetic systems. These principles include how to promote and control: 1) energy capture, charge separation, and long-range directional energy and charge transport, 2) coupling of separated charges to multi-electron catalysts for fuel formation, and 3) supramolecular self-assembly for scalable, low-cost processing from the nanoscale to the macroscale. The central scientific challenge is to develop small, functional building blocks, having a minimum number of covalent linkages, which also have the appropriate molecular recognition properties to facilitate self-assembly of complete, functional artificial photosynthetic systems. This lecture will describe our use of ultrafast optical spectroscopy and time-resolved EPR spectroscopy to understand charge transport in self-assembled structures for artificial photosynthesis.

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

    SciTech Connect

    Zamaraev, K.I.; Parmon, V.N.

    1980-01-01

    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 into electrical or chemical energy of fossil fuels make them much more attractive for large scale use. For high efficiency of solar energy conversion, the development of moleuclar photocatalytic systems for solar energy conversion - a kind of simplified analog to natural photosynthesizing systems seem very attractive. For obtaining the highest possible efficiency, systems which do not involve free radicals and free atom intermediates appear to be the most advantageous. 345 references. (BLM)

  11. Direct fission fragment energy conversion utilizing magnetic collimation

    NASA Astrophysics Data System (ADS)

    Tsvetkov, Pavel Valeryevich

    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 codes that allowed realistic and consistent modeling of the important physical processes governing DFFEC-MC system performance. Unique computational schemes, including three-dimensional modeling, were constructed and applied to obtain the performance characteristics of DFFEC-MC systems. Special effort was made to include all important physical processes. Important simplifications introduced due to modeling limitations were also assessed. The analysis takes into consideration a wide range of operational aspects including fission fragment (FF) escape from the fuel, FF collimation, FF collection, criticality, long-term performance, energy conversion efficiency, heat removal, and safety characteristics. Required engineering conditions are formulated that must be satisfied in order for the DFFEC-MC concept to have a reasonable chance to demonstrate technological feasibility. Specific characteristics of individual system components and the entire DFFEC-MC system are evaluated. To identify which technological improvements are needed, several possible design solutions are provided for some of the components along with analyses of the corresponding DFFEC-MC system performance. As a result of the computational analysis, the conditions for achieving an attractive (high) system efficiency are demonstrated. A technologically feasible DFFEC-MC system layout with promising operational characteristics is presented. The resulting DFFEC-MC system is envisioned as an advanced DFFEC system that combines advantageous design solutions

  12. Refractory materials for high-temperature thermoelectric energy conversion

    NASA Technical Reports Server (NTRS)

    Wood, C.; Emin, D.

    1984-01-01

    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.

  13. Refractory materials for high-temperature thermoelectric energy conversion

    NASA Technical Reports Server (NTRS)

    Wood, C.; Emin, D.

    1983-01-01

    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 estimation 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.

  14. Calculation of absolute free energy of binding for theophylline and its analogs to RNA aptamer using nonequilibrium work values

    NASA Astrophysics Data System (ADS)

    Tanida, Yoshiaki; Ito, Masakatsu; Fujitani, Hideaki

    2007-08-01

    The massively parallel computation of absolute binding free energy with a well-equilibrated system (MP-CAFEE) has been developed [H. Fujitani, Y. Tanida, M. Ito, G. Jayachandran, C.D. Snow, M.R. Shirts, E.J. Sorin, V.S. Pande, J. Chem. Phys. 123 (2005) 084108]. As an application, we perform the binding affinity calculations of six theophylline-related ligands with RNA aptamer. Basically, our method is applicable when using many compute nodes to accelerate simulations, thus a parallel computing system is also developed. To further reduce the computational cost, the adequate non-uniform intervals of coupling constant λ, connecting two equilibrium states, namely bound and unbound, are determined. The absolute binding energies Δ G thus obtained have effective linear relation between the computed and experimental values. If the results of two other different methods are compared, thermodynamic integration (TI) and molecular mechanics Poisson-Boltzmann surface area (MM-PBSA) by the paper of Gouda et al. [H. Gouda, I.D. Kuntz, D.A. Case, P.A. Kollman, Biopolymers 68 (2003) 16], the predictive accuracy of the relative values ΔΔ G is almost comparable to that of TI: the correlation coefficients ( R) obtained are 0.99 (this work), 0.97 (TI), and 0.78 (MM-PBSA). On absolute binding energies meanwhile, a constant energy shift of ˜-7 kcal/mol against the experimental values is evident. To solve this problem, several presumable reasons are investigated.

  15. Carbon-based electrocatalysts for advanced energy conversion and storage

    PubMed Central

    Zhang, Jintao; Xia, Zhenhai; Dai, Liming

    2015-01-01

    Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) play curial roles in electrochemical energy conversion and storage, including fuel cells and metal-air batteries. Having rich multidimensional nanoarchitectures [for example, zero-dimensional (0D) fullerenes, 1D carbon nanotubes, 2D graphene, and 3D graphite] with tunable electronic and surface characteristics, various carbon nanomaterials have been demonstrated to act as efficient metal-free electrocatalysts for ORR and OER in fuel cells and batteries. We present a critical review on the recent advances in carbon-based metal-free catalysts for fuel cells and metal-air batteries, and discuss the perspectives and challenges in this rapidly developing field of practical significance. PMID:26601241

  16. Tandem photovoltaic solar cells and increased solar energy conversion efficiency

    NASA Technical Reports Server (NTRS)

    Loferski, J. J.

    1976-01-01

    Tandem photovoltaic cells, as proposed by Jackson (1955) to increase the efficiency of solar energy conversion, involve the construction of a system of stacked p/n homojunction photovoltaic cells composed of different semiconductors. It had been pointed out by critics, however, that the total power which could be extracted from the cells in the stack placed side by side was substantially greater than the power obtained from the stacked cells. A reexamination of the tandem cell concept in view of the development of the past few years is conducted. It is concluded that the use of tandem cell systems in flat plate collectors, as originally envisioned by Jackson, may yet become feasible as a result of the development of economically acceptable solar cells for large scale terrestrial power generation.

  17. Monolithic Interconnected Modules (MIMs) for Thermophotovoltaic Energy Conversion

    NASA Technical Reports Server (NTRS)

    Wilt, David; Wehrer, Rebecca; Palmisiano, Marc; Wanlass, Mark; Murray, Christopher

    2003-01-01

    Monolithic Interconnected Modules (MIM) are under development for thermophotovoltaic (TPV) energy conversion applications. MIM devices are typified by series-interconnected photovoltaic cells on a common, semi-insulating substrate and generally include rear-surface infrared (IR) reflectors. The MIM architecture is being implemented in InGaAsSb materials without semi-insulating substrates through the development of alternative isolation methodologies. Motivations for developing the MIM structure include: reduced resistive losses, higher output power density than for systems utilizing front surface spectral control, improved thermal coupling and ultimately higher system efficiency. Numerous design and material changes have been investigated since the introduction of the MIM concept in 1994. These developments as well as the current design strategies are addressed.

  18. Materials and structures for stretchable energy storage and conversion devices.

    PubMed

    Xie, Keyu; Wei, Bingqing

    2014-06-11

    Stretchable energy storage and conversion devices (ESCDs) are attracting intensive attention due to their promising and potential applications in realistic consumer products, ranging from portable electronics, bio-integrated devices, space satellites, and electric vehicles to buildings with arbitrarily shaped surfaces. Material synthesis and structural design are core in the development of highly stretchable supercapacitors, batteries, and solar cells for practical applications. This review provides a brief summary of research development on the stretchable ESCDs in the past decade, from structural design strategies to novel materials synthesis. The focuses are on the fundamental insights of mechanical characteristics of materials and structures on the performance of the stretchable ESCDs, as well as challenges for their practical applications. Finally, some of the important directions in the areas of material synthesis and structural design facing the stretchable ESCDs are discussed.

  19. Photochemical energy conversion: from molecular dyads to solar cells.

    PubMed

    Durrant, James R; Haque, Saif A; Palomares, Emilio

    2006-08-21

    Photochemical approaches to solar energy conversion are currently making rapid progress, increasing not only academic but also commercial interest in molecular-based photovoltaic solar cells. This progress has been achieved not only by increased understanding of the physics and physical chemistry of device function but also through advances in chemical and materials synthesis and processing, which now allows the design and fabrication of increasingly sophisticated device structures organised on the nanometer length scale. In this feature article, we review some progress in this field, focusing in particular upon the electron-transfer dynamics which underlie the function of dye-sensitised, nanocrystalline solar cells. The article starts by building upon the parallels between the function of such devices and the function of simple donor/acceptor molecular systems in solution. We then go on to discuss the optimisation of device function, and in particular the use of self-assembly-based strategies to control interfacial electron-transfer kinetics.

  20. Siting handbook for small wind energy conversion systems

    SciTech Connect

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

    1980-03-01

    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.

  1. Comparison of performances of turbines for wave energy conversion

    NASA Astrophysics Data System (ADS)

    Kinoue, Yoichi; Setoguchi, Toshiaki; Kuroda, Tomohiko; Kaneko, Kenji; Takao, Manabu; Thakker, Ajit

    2003-11-01

    The Wells turbine for a wave power generator is a self-rectifying air turbine that is available for an energy conversion in an oscillating water-air column without any rectifying valve. The objective of this paper is to compare the performances of the Wells turbines in which the profile of blade are NACA0020, NACA0015, CA9 and HSIM15-262123-1576 in the small-scale model testing. The running characteristics in the steady flow, the start and running characteristics in the sinusoidal flow and the hysteretic characteristics in the sinusoidal flow were investigated for four kinds of turbine. As a conclusion, the turbine in which the profile of blade is NACA0020 has the best performances among 4 turbines for the running and starting characteristics in the small-scale model testing.

  2. Shelf mounted ocean thermal energy conversion platform, revised preliminary report

    NASA Astrophysics Data System (ADS)

    1984-03-01

    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 plant 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.

  3. Improvement of flat plate collectors for solar energy conversion

    NASA Astrophysics Data System (ADS)

    Boeck, H.; Hallermayer, R.; Schoelkopf, W.; Sizman, R.

    1984-03-01

    Selective absorption for thermal conversion of radiative energy was investigated. Improvement and operation of various measuring devices for absorption and emission are presented. Selective coatings were produced by vapor deposition and galvanic treatment. Calculations of the transmittance of turbular collector fields are presented. Operational Characteristics of Collector were examined. A collector test field with simultaneous recording of data from 24 collectors or uncovered absorbers was built and connected to a high performance microprocessor system. The transient behavior of collectors by variation of the irradiation and the collector inlet temperature were investigated. A mechanism for stratification of hot water of fluctuating inlet temperature in a storage tank was studied. The operating conditions of a heat pump installed in the collector test plant are investigated. A large domestic hot water system is equipped with temperature sensors and flowmeters for computer recording.

  4. Photochemical energy conversion by membrane-bound photoredox systems

    SciTech Connect

    Tollin, G.

    1992-03-01

    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 is 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.

  5. Carbon-based electrocatalysts for advanced energy conversion and storage.

    PubMed

    Zhang, Jintao; Xia, Zhenhai; Dai, Liming

    2015-08-01

    Oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) play curial roles in electrochemical energy conversion and storage, including fuel cells and metal-air batteries. Having rich multidimensional nanoarchitectures [for example, zero-dimensional (0D) fullerenes, 1D carbon nanotubes, 2D graphene, and 3D graphite] with tunable electronic and surface characteristics, various carbon nanomaterials have been demonstrated to act as efficient metal-free electrocatalysts for ORR and OER in fuel cells and batteries. We present a critical review on the recent advances in carbon-based metal-free catalysts for fuel cells and metal-air batteries, and discuss the perspectives and challenges in this rapidly developing field of practical significance.

  6. Plasmon enhanced solar-to-fuel energy conversion.

    PubMed

    Thomann, Isabell; Pinaud, Blaise A; Chen, Zhebo; Clemens, Bruce M; Jaramillo, Thomas F; Brongersma, Mark L

    2011-08-10

    Future generations of photoelectrodes for solar fuel generation must employ inexpensive, earth-abundant absorber materials in order to provide a large-scale source of clean energy. These materials tend to have poor electrical transport properties and exhibit carrier diffusion lengths which are significantly shorter than the absorption depth of light. As a result, many photoexcited carriers are generated too far from a reactive surface and recombine instead of participating in solar-to-fuel conversion. We demonstrate that plasmonic resonances in metallic nanostructures and multilayer interference effects can be engineered to strongly concentrate sunlight close to the electrode/liquid interface, precisely where the relevant reactions take place. On comparison of spectral features in the enhanced photocurrent spectra to full-field electromagnetic simulations, the contribution of surface plasmon excitations is verified. These results open the door to the optimization of a wide variety of photochemical processes by leveraging the rapid advances in the field of plasmonics.

  7. Waterborne noise due to ocean thermal energy conversion plants

    SciTech Connect

    Janota, C.P.; Thompson, D.E.

    1983-07-01

    Public law reflects a United States national commitment to the rapid development of Ocean Thermal Energy Conversion (OTEC) as an alternate energy source. OTEC plants extract the stored solar energy from the world's tropical seas and in so doing pose a potential for altering the character of the ambient noise there. The sources of noise from an OTEC plant are analyzed in the context of four configurations, two of which were built and tested, and two which are concepts for future full-scale moored facilities. The analysis indicates that the noise resulting from the interaction of turbulence with the seawater pumps is expected to dominate in the frequency range 10 Hz to 1 kHz. Measured radiated noise data from the OTEC-I research plant, located near the island of Hawaii, are compared with the analysis. The measured data diverge from the predicted levels at frequencies above about 60 Hz because of dominant non-OTEC noise sources on this platform. However, at low frequency, the measured broadband noise is comparable to that predicted.

  8. Thermal energy conversion by coupled shape memory and piezoelectric effects

    NASA Astrophysics Data System (ADS)

    Zakharov, Dmitry; Lebedev, Gor; Cugat, Orphee; Delamare, Jerome; Viala, Bernard; Lafont, Thomas; Gimeno, Leticia; Shelyakov, Alexander

    2012-09-01

    This work gives experimental evidence of a promising method of thermal-to-electric energy conversion by coupling shape memory effect (SME) and direct piezoelectric effect (DPE) for harvesting quasi-static ambient temperature variations. Two original prototypes of thermal energy harvesters have been fabricated and tested experimentally. The first is a hybrid laminated composite consisting of TiNiCu shape memory alloy (SMA) and macro fiber composite piezoelectric. This composite comprises 0.1 cm3 of active materials and harvests 75 µJ of energy for each temperature variation of 60 °C. The second prototype is a SME/DPE ‘machine’ which uses the thermally induced linear strains of the SMA to bend a bulk PZT ceramic plate through a specially designed mechanical structure. The SME/DPE ‘machine’ with 0.2 cm3 of active material harvests 90 µJ over a temperature increase of 35 °C (60 µJ when cooling). In contrast to pyroelectric materials, such harvesters are also compatible with both small and slow temperature variations.

  9. Impact of Atomic Structure on Absolute Energy Levels of Methylammonium Lead Iodide Perovskite

    NASA Astrophysics Data System (ADS)

    Choi, Joshua

    2015-03-01

    There has been a staggeringly rapid increase in the photovoltaic performance of methylammonium lead iodide (MAPbI3) perovskite - greater than 19 percent solar cell power conversion efficiency has been reported in less than five years since the first report in 2009. Despite the progress in device performance, structure-property relationships in MAPbI3 are still poorly understood. I will present our recent findings on the impact of changing the Pb-I bond length and Pb-I-Pb bond angle on the electronic structure of MAPbI3. By using the combination of temperature dependent X-ray scattering, ultraviolet photoelectron spectroscopy, absorbance and PL spectroscopy, we show that the energy levels of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) shift in the same direction as MAPbI3 goes through tetragonal-to-cubic structural phase transition wherein the rotational angle of PbI6 octahedra is the order parameter of the transition. Our experimental results are corroborated by density functional theory calculations which show that the lattice expansion and bond angle distortion cause different degree of orbital overlap between the Pb and I atoms and the anti-bonding orbital nature of both HOMO and LUMO results in the same direction of their shift. Moreover, through pair distribution function analysis of X-ray scattering, we discovered that the majority of MAPbI3 in thin film solar cell layer has highly disordered structure with a coherence range of only 1.4 nm. The nanostructuring correlates with a blueshift of the absorption onset and increases the photoluminescence. Our results underscore the importance of understanding the structure-property relationships in order to improve the device performance of metal-organic perovskites.

  10. Electro-mechanical energy conversion system having a permanent magnet machine with stator, resonant transfer link and energy converter controls

    DOEpatents

    Skeist, S. Merrill; Baker, Richard H.

    2006-01-10

    An electro-mechanical energy conversion system coupled between an energy source and an energy load comprising an energy converter device including a permanent magnet induction machine coupled between the energy source and the energy load to convert the energy from the energy source and to transfer the converted energy to the energy load and an energy transfer multiplexer to control the flow of power or energy through the permanent magnetic induction machine.

  11. Segregated tandem filter for enhanced conversion efficiency in a thermophotovoltaic energy conversion system

    DOEpatents

    Brown, Edward J.; Baldasaro, Paul F.; Dziendziel, Randolph J.

    1997-01-01

    A filter system to transmit short wavelength radiation and reflect long wavelength radiation for a thermophotovoltaic energy conversion cell comprises an optically transparent substrate segregation layer with at least one coherent wavelength in optical thickness; a dielectric interference filter deposited on one side of the substrate segregation layer, the interference filter being disposed toward the source of radiation, the interference filter including a plurality of alternating layers of high and low optical index materials adapted to change from transmitting to reflecting at a nominal wavelength .lambda..sub.IF approximately equal to the bandgap wavelength .lambda..sub.g of the thermophotovoltaic cell, the interference filter being adapted to transmit incident radiation from about 0.5.lambda..sub.IF to .lambda..sub.IF and reflect from .lambda..sub.IF to about 2.lambda..sub.IF ; and a high mobility plasma filter deposited on the opposite side of the substrate segregation layer, the plasma filter being adapted to start to become reflecting at a wavelength of about 1.5.lambda..sub.IF.

  12. Segregated tandem filter for enhanced conversion efficiency in a thermophotovoltaic energy conversion system

    DOEpatents

    Brown, E.J.; Baldasaro, P.F.; Dziendziel, R.J.

    1997-12-23

    A filter system to transmit short wavelength radiation and reflect long wavelength radiation for a thermophotovoltaic energy conversion cell comprises an optically transparent substrate segregation layer with at least one coherent wavelength in optical thickness; a dielectric interference filter deposited on one side of the substrate segregation layer, the interference filter being disposed toward the source of radiation, the interference filter including a plurality of alternating layers of high and low optical index materials adapted to change from transmitting to reflecting at a nominal wavelength {lambda}{sub IF} approximately equal to the bandgap wavelength {lambda}{sub g} of the thermophotovoltaic cell, the interference filter being adapted to transmit incident radiation from about 0.5{lambda}{sub IF} to {lambda}{sub IF} and reflect from {lambda}{sub IF} to about 2{lambda}{sub IF}; and a high mobility plasma filter deposited on the opposite side of the substrate segregation layer, the plasma filter being adapted to start to become reflecting at a wavelength of about 1.5{lambda}{sub IF}. 10 figs.

  13. Advanced Energy Conversion Technologies and Architectures for Earth and Beyond

    NASA Technical Reports Server (NTRS)

    Howell, Joe T.; Fikes, John C.; Phillips, Dane J.; Laycock, Rustin L.; ONeill, Mark; Henley, Mark W.; Fork, Richard L.

    2006-01-01

    Research, development and studies of novel space-based solar power systems, technologies and architectures for Earth and beyond are needed to reduce the cost of clean electrical power for terrestrial use and to provide a stepping stone for providing an abundance of power in space, i.e., manufacturing facilities, tourist facilities, delivery of power between objects in space, and between space and surface sites. The architectures, technologies and systems needed for space to Earth applications may also be used for in-space applications. Advances in key technologies, i.e., power generation, power management and distribution, power beaming and conversion of beamed power are needed to achieve the objectives of both terrestrial and extraterrestrial applications. There is a need to produce "proof-ofconcept" validation of critical WPT technologies for both the near-term, as well as far-term applications. Investments may be harvested in near-term beam safe demonstrations of commercial WPT applications. Receiving sites (users) include ground-based stations for terrestrial electrical power, orbital sites to provide power for satellites and other platforms, future space elevator systems, space vehicle propulsion, and space surface sites. Space surface receiving sites of particular interest include the areas of permanent shadow near the moon s North and South poles, where WPT technologies could enable access to ice and other useful resources for human exploration. This paper discusses work addressing a promising approach to solar power generation and beamed power conversion. The approach is based on a unique high-power solar concentrator array called Stretched Lens Array (SLA) applied to both solar power generation and beamed power conversion. Since both versions (solar and laser) of SLA use many identical components (only the photovoltaic cells need to be different), economies of manufacturing and scale may be realized by using SLA on both ends of the laser power beaming

  14. Energy Conversion from Salinity Gradient Using Microchip with Nafion Membrane

    NASA Astrophysics Data System (ADS)

    Chang, Che-Rong; Yeh, Ching-Hua; Yeh, Hung-Chun; Yang, Ruey-Jen

    2016-06-01

    When a concentrated salt solution and a diluted salt solution are separated by an ion-selective membrane, cations and anions would diffuse at different rates depending on the ion selectivity of the membrane. The difference of positive and negative charges at both ends of the membrane would produce a potential, called the diffusion potential. Thus, electrical energy can be converted from the diffusion potential through reverse electrodialysis. This study demonstrated the fabrication of an energy conversion microchip using the standard micro-electromechanical technique, and utilizing Nafion junction as connecting membrane, which was fabricated by a surface patterned process. Through different salinity gradient of potassium chloride solutions, we experimentally investigated the diffusion potential and power generation from the microchip, and the highest value measured was 135 mV and 339 pW, respectively. Furthermore, when the electrolyte was in pH value of 3.8, 5.6, 10.3, the system exhibited best performance at pH value of 10.3; whereas, pH value of 3.8 yielded the worst.

  15. Enhanced photovoltaic energy conversion using thermally based spectral shaping

    NASA Astrophysics Data System (ADS)

    Bierman, David M.; Lenert, Andrej; Chan, Walker R.; Bhatia, Bikram; Celanović, Ivan; Soljačić, Marin; Wang, Evelyn N.

    2016-06-01

    Solar thermophotovoltaic devices have the potential to enhance the performance of solar energy harvesting by converting broadband sunlight to narrow-band thermal radiation tuned for a photovoltaic cell. A direct comparison of the operation of a photovoltaic with and without a spectral converter is the most critical indicator of the promise of this technology. Here, we demonstrate enhanced device performance through the suppression of 80% of unconvertible photons by pairing a one-dimensional photonic crystal selective emitter with a tandem plasma-interference optical filter. We measured a solar-to-electrical conversion rate of 6.8%, exceeding the performance of the photovoltaic cell alone. The device operates more efficiently while reducing the heat generation rates in the photovoltaic cell by a factor of two at matching output power densities. We determined the theoretical limits, and discuss the implications of surpassing the Shockley-Queisser limit. Improving the performance of an unaltered photovoltaic cell provides an important framework for the design of high-efficiency solar energy converters.

  16. Environmental programs for ocean thermal energy conversion (OTEC)

    SciTech Connect

    Wilde, P.

    1981-07-01

    The environmental research effort in support of the US Department of Energy's Ocean Thermal Energy Conversion (OTEC) program has the goal of providing documented information on the effect of proposed operations on the ocean and the effect of oceanic conditions on the plant. The associated environment program consists of archival studies in potential areas serial oceanographic cruises to sites or regions of interest, studies from various fixed platforms at sites, and compilation of such information for appropriate legal compliance and permit requirements and for use in progressive design of OTEC plants. Site/regions investigated are south of Mobile and west of Tampa, Gulf of Mexico; Punta Tuna, Puerto Rico; St. Croix, Virgin Islands; Kahe Point, Oahu and Keahole Point, Hawaii, Hawaiian Islands; and off the Brazilian south Equatorial Coast. Four classes of environmental concerns identified are: redistribution of oceanic properties (ocean water mixing, impingement/entrainment etc.); chemical pollution (biocides, working fluid leaks, etc.); structural effects (artificial reef, aggregation, nesting/migration, etc.); socio-legal-economic (worker safety, enviromaritime law, etc.).

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

    SciTech Connect

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

    1983-07-01

    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 by direct contact with water drawn from a 700-m depth through a 1.6m-diam, 1.75-km-long cold-water pipe (CWP). From a delta T of 14/sup 0/C his undersized turbine generated 22 kW. In 1956 a French team designed a 3.5-MW (net) open-cycle plant for installation off Abidjan on the Ivory Coast of Africa and demonstrated the necessary CWP deployment. The at-sea demonstrations by Mini-OTEC and OTEC-1 and other recent advances in OTEC technology summarized herein represent great progress. All of the types of plants proposed for the DOE's PON program may be worthy of development; certainly work on a grazing plant is needed. Our estimates indicate that the U.S. goals established by Public Law 96-310 leading to 10 GW of OTEC power and energy product equivalents by 1999 are achievable, provided that adequate federal financial incentives are retained to assure the building of the first few plants.

  18. An energy conversion relationship predictive of conversion profiles and depth of cure for resin-based composite.

    PubMed

    Halvorson, Rolf H; Erickson, Robert L; Davidson, Carel L

    2003-01-01

    Predicting the polymerization throughout resin-based composite (RBC) has been reduced to a set of variables involving irradiance of the light source, exposure duration and RBC transmission properties, together with an energy-conversion relationship (ECR) derived from Fourier Transform Infrared Spectroscopic analysis (FTIR) of a single shade of photo-polymerized RBC. The ECR describes the localized energy density required to achieve a desired conversion independent of shade. Using this ECR, conversion was predicted and experimentally verified throughout different opacities of RBC based on knowledge of their transmission properties and the incident radiant energy density (irradiance times exposure time). Also, using RBC transmission properties, a critical scrape-back energy of approximately 32 mJcm(-2) was determined from cylindrical samples of photo-polymerized RBC in which the poorly polymerized material was removed. This value correlates to approximately 22% conversion. The critical scrape-back energy was then used to predict scrape-back lengths obtained from samples polymerized at various energy densities. These results confirm the logarithmic relationship between depth of cure and energy of exposure and the reciprocal relationship between irradiance and time of exposure.

  19. Dynamic instabilities and energy conversion processes in hurricane core regions

    NASA Astrophysics Data System (ADS)

    Kwon, Young C.

    A series of numerical simulations of axisymmetric hurricane-like vortices is performed to examine dynamic instabilities and energy conversion processes in a hurricane core area. The numerical experiments in this study consist of simulations of idealized dry vortices and moist vortices. The dry experiment is designed to show that the existence of baroclinic and barotropic instabilities is possible in realistic hurricane-like vortices. In order to generalize the dry simulation results, the simulations are extended to more realistic moist vortices. All numerical experiments are performed using the Pennsylvania State University/National Center for Atmospheric Research Mesoscale Model version 5 (PSU/NCAR MM5) with a 6km horizontal grid. Three steady-state vortices are designed for the dry experiments. A control vortex is built based on the results of a simulation of Hurricane Floyd (1999). Then, two axisymmetric vortices, EXP-1 and EXP-2, are constructed by modifying the wind and mass fields of the control vortex. The EXP-1 vortex is designed to satisfy the necessary condition of baroclinic instability, while the EXP-2 vortex satisfies the necessary condition of barotropic instability. These modified vortices are thought to lie within the natural range of the structural variability of hurricanes. In order to focus on internal effects on the stability of the dry vortices, all external forcings are eliminated. The dry vortices are constructed on an f-plane, and the experiments are performed without moist and boundary layer processes. The stability of the dry vortices is examined by analyzing the behavior of small magnitude of an initial perturbations imposed on the vortices. When a vortex is found to be unstable, the type of instability is determined by the energy source of a growing perturbation. To identify the energy source of the perturbation, a linearized eddy energy equation is derived. The EXP-1 and EXP-2 vortices are found to be unstable with respect to small

  20. Nanostructured semiconductors for thermoelectric energy conversion: Synthesis and transport properties

    NASA Astrophysics Data System (ADS)

    Sahoo, Pranati

    Increasing energy demands and decreasing natural energy resources have sparked search for alternative clean and renewable energy sources. For instance, currently there is a tremendous interest in thermoelectric and photovoltaic solar energy production technologies. Half-Heusler (HH) alloys are among the most popular material systems presently under widespread investigations for high temperature thermoelectric energy conversion. Approaches to increase the thermoelectric figure of merit (ZT) of HH range from (1) chemical substitution of atoms with different masses within the same atomic position in the crystal structure to optimize carrier concentration and enhance phonon scattering via mass fluctuation and (2) embedding secondary phonon scattering centers in the matrix (nanostructuring) to further reduce thermal conductivity. This work focuses on three material systems. The first part describes the synthesis and properties (thermal conductivity, electrical conductivity, magnetic) of various oxide nanostructures (NiO, Co3O4) which were subsequently used as inclusion phases in a HH matrix to reduce the thermal conductivity. Detailed reviews of the past efforts along with the current effort to optimize synthetic routes are presented. The effects of the synthesis conditions on the thermoelectric properties of compacted pellets of NiO and Co3O4 are also discussed. The second part of the work discusses the development of synthetic strategies for the fabrication of p-type and n-type bulk nanostructured thermoelectric materials made of a half-Heusler matrix based on (Ti,Hf)CoSb, containing nanostructures with full-Heusler (FH) compositions and structures coherently embedded inside the half-Heusler matrix. The role of the nanostructures in the regulation of phonon and charge carrier transports within the half-heusler matrix is extensively discussed by combining transport data and electron microscopy images. It was found that the FH nanoinclusions form staggered

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

    NASA Technical Reports Server (NTRS)

    Baresi, Larry

    1989-01-01

    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.

  2. Direct Energy Conversion for Nuclear Propulsion at Low Specific Mass

    NASA Technical Reports Server (NTRS)

    Scott, John H.

    2014-01-01

    The project will continue the FY13 JSC IR&D (October-2012 to September-2013) effort in Travelling Wave Direct Energy Conversion (TWDEC) in order to demonstrate its potential as the core of a high potential, game-changing, in-space propulsion technology. The TWDEC concept converts particle beam energy into radio frequency (RF) alternating current electrical power, such as can be used to heat the propellant in a plasma thruster. In a more advanced concept (explored in the Phase 1 NIAC project), the TWDEC could also be utilized to condition the particle beam such that it may transfer directed kinetic energy to a target propellant plasma for the purpose of increasing thrust and optimizing the specific impulse. The overall scope of the FY13 first-year effort was to build on both the 2012 Phase 1 NIAC research and the analysis and test results produced by Japanese researchers over the past twenty years to assess the potential for spacecraft propulsion applications. The primary objective of the FY13 effort was to create particle-in-cell computer simulations of a TWDEC. Other objectives included construction of a breadboard TWDEC test article, preliminary test calibration of the simulations, and construction of first order power system models to feed into mission architecture analyses with COPERNICUS tools. Due to funding cuts resulting from the FY13 sequestration, only the computer simulations and assembly of the breadboard test article were completed. The simulations, however, are of unprecedented flexibility and precision and were presented at the 2013 AIAA Joint Propulsion Conference. Also, the assembled test article will provide an ion current density two orders of magnitude above that available in previous Japanese experiments, thus enabling the first direct measurements of power generation from a TWDEC for FY14. The proposed FY14 effort will use the test article for experimental validation of the computer simulations and thus complete to a greater fidelity the

  3. Energy Conversion Advanced Heat Transport Loop and Power Cycle

    SciTech Connect

    Oh, C. H.

    2006-08-01

    The Department of Energy and the Idaho National Laboratory are developing a Next Generation Nuclear Plant (NGNP) to serve as a demonstration of state-of-the-art nuclear technology. The purpose of the demonstration is two fold 1) efficient low cost energy generation and 2) hydrogen production. Although a next generation plant could be developed as a single-purpose facility, early designs are expected to be dual-purpose. While hydrogen production and advanced energy cycles are still in its early stages of development, research towards coupling a high temperature reactor, electrical generation and hydrogen production is under way. Many aspects of the NGNP must be researched and developed in order to make recommendations on the final design of the plant. Parameters such as working conditions, cycle components, working fluids, and power conversion unit configurations must be understood. Three configurations of the power conversion unit were demonstrated in this study. A three-shaft design with 3 turbines and 4 compressors, a combined cycle with a Brayton top cycle and a Rankine bottoming cycle, and a reheated cycle with 3 stages of reheat were investigated. An intermediate heat transport loop for transporting process heat to a High Temperature Steam Electrolysis (HTSE) hydrogen production plant was used. Helium, CO2, and an 80% nitrogen, 20% helium mixture (by weight) were studied to determine the best working fluid in terms cycle efficiency and development cost. In each of these configurations the relative component size were estimated for the different working fluids. The relative size of the turbomachinery was measured by comparing the power input/output of the component. For heat exchangers the volume was computed and compared. Parametric studies away from the baseline values of the three-shaft and combined cycles were performed to determine the effect of varying conditions in the cycle. This gives some insight into the sensitivity of these cycles to various

  4. Methods for locating ground faults and insulation degradation condition in energy conversion systems

    DOEpatents

    Agamy, Mohamed; Elasser, Ahmed; Galbraith, Anthony William; Harfman Todorovic, Maja

    2015-08-11

    Methods for determining a ground fault or insulation degradation condition within energy conversion systems are described. A method for determining a ground fault within an energy conversion system may include, in part, a comparison of baseline waveform of differential current to a waveform of differential current during operation for a plurality of DC current carrying conductors in an energy conversion system. A method for determining insulation degradation within an energy conversion system may include, in part, a comparison of baseline frequency spectra of differential current to a frequency spectra of differential current transient at start-up for a plurality of DC current carrying conductors in an energy conversion system. In one embodiment, the energy conversion system may be a photovoltaic system.

  5. Symposium on the Physical Chemistry of Solar Energy Conversion, Indianapolis American Chemical Society Meetings, Fall 2013

    SciTech Connect

    Lian, Tianquan

    2013-09-20

    The Symposium on the Physical Chemistry of Solar Energy Conversion at the Fall ACS Meeting in Indianapolis, IN (Sept. 8-12) featured the following sessions (approx. 6 speakers per session): (1) Quantum Dots and Nanorods for Solar Energy Conversion (2 half-day sessions); (2) Artificial Photosynthesis: Water Oxidation; (3) Artificial Photosynthesis: Solar Fuels (2 half-day sessions); (4) Organic Solar Cells; (5) Novel Concepts for Solar Energy Conversion (2 half-day sessions); (6) Emerging Techniques for Solar Energy Conversion; (7) Interfacial Electron Transfer

  6. Overall energy conversion efficiency of a photosynthetic vesicle.

    PubMed

    Sener, Melih; Strumpfer, Johan; Singharoy, Abhishek; Hunter, C Neil; Schulten, Klaus

    2016-08-26

    The chromatophore of purple bacteria is an intracellular spherical vesicle that exists in numerous copies in the cell and that efficiently converts sunlight into ATP synthesis, operating typically under low light conditions. Building on an atomic-level structural model of a low-light-adapted chromatophore vesicle from Rhodobacter sphaeroides, we investigate the cooperation between more than a hundred protein complexes in the vesicle. The steady-state ATP production rate as a function of incident light intensity is determined after identifying quinol turnover at the cytochrome bc1 complex (cytb⁢c1) as rate limiting and assuming that the quinone/quinol pool of about 900 molecules acts in a quasi-stationary state. For an illumination condition equivalent to 1% of full sunlight, the vesicle exhibits an ATP production rate of 82 ATP molecules/s. The energy conversion efficiency of ATP synthesis at illuminations corresponding to 1%-5% of full sunlight is calculated to be 0.12-0.04, respectively. The vesicle stoichiometry, evolutionarily adapted to the low light intensities in the habitat of purple bacteria, is suboptimal for steady-state ATP turnover for the benefit of protection against over-illumination.

  7. Amphoteric oxide semiconductors for energy conversion devices: a tutorial review.

    PubMed

    Singh, Kalpana; Nowotny, Janusz; Thangadurai, Venkataraman

    2013-03-07

    In this tutorial review, we discuss the defect chemistry of selected amphoteric oxide semiconductors in conjunction with their significant impact on the development of renewable and sustainable solid state energy conversion devices. The effect of electronic defect disorders in semiconductors appears to control the overall performance of several solid-state ionic devices that include oxide ion conducting solid oxide fuel cells (O-SOFCs), proton conducting solid oxide fuel cells (H-SOFCs), batteries, solar cells, and chemical (gas) sensors. Thus, the present study aims to assess the advances made in typical n- and p-type metal oxide semiconductors with respect to their use in ionic devices. The present paper briefly outlines the key challenges in the development of n- and p-type materials for various applications and also tries to present the state-of-the-art of defect disorders in technologically related semiconductors such as TiO(2), and perovskite-like and fluorite-type structure metal oxides.

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

    SciTech Connect

    Authors, Various

    1980-01-01

    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.

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

    SciTech Connect

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

    1981-02-01

    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)

  10. Advanced materials development for fossil energy conversion applications

    SciTech Connect

    Bates, J.L.; Chick, L.A.; Kingsley, J.J.; Pederson, L.R.; Weber, W.J.; Youngblood, G.E. ); Hurst, J.K.; Bell, A.E.; Grainger, D.W.; Rananavare, S.B.; Roe, D.K.; Thompson, D.H. )

    1992-05-01

    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.

  11. Calibration of sonic flowmeters for Ocean Thermal Energy Conversion (OTEC)

    NASA Astrophysics Data System (ADS)

    Lott, D. F.; Salsman, G. G.; Hodges, C. E.

    1980-12-01

    Scientists at the Naval Coastal Systems Center (NCSC) at Panama City, Florida, have used a commercially available acoustic flowmeter to monitor critical flow conditions during an OTEC (Ocean Thermal Energy Conversion) funded study of the effects of biofouling on the efficiency of a prototype heat transfer system. Flowmeters of this type are particularly useful in applications requiring unimpeded flow; i.e., no sensor projecting into the moving fluid. Unfortunately, sonic flowmeters are somewhat difficult to calibrate and may be subject to drift. A method of calibration devised by NCSC may thus be of some interest to other users. It is the purpose of this report to document the special procedures used by test personnel to calibrate the flowmeters. Briefly, the calibration consisted of pumping sea water through the flowmeter into a tank suspended beneath a special load cell which provided an output voltage proportional to the weight of water in the tank. A programmable desktop calculator system was used to monitor changes in voltage as a function of time and convert these changes into flow rates for direct comparison with values read from the sonic flowmeter's digital display. Calibration checks were made at metered flows of 8, 10, 12, 14, 16, and 18 gallons per minute (gpm). It was found that computed flows were essentially linear but differed from metered values by as much as 9.0 percent.

  12. Thermionic Energy Conversion Based on Graphene van der Waals Heterostructures

    PubMed Central

    Liang, Shi-Jun; Liu, Bo; Hu, Wei; Zhou, Kun; Ang, L. K.

    2017-01-01

    Seeking for thermoelectric (TE) materials with high figure of merit (or ZT), which can directly converts low-grade wasted heat (400 to 500 K) into electricity, has been a big challenge. Inspired by the concept of multilayer thermionic devices, we propose and design a solid-state thermionic devices (as a power generator or a refrigerator) in using van der Waals (vdW) heterostructure sandwiched between two graphene electrodes, to achieve high energy conversion efficiency in the temperature range of 400 to 500 K. The vdW heterostructure is composed of suitable multiple layers of transition metal dichalcogenides (TMDs), such as MoS2, MoSe2, WS2 and WSe2. From our calculations, WSe2 and MoSe2 are identified as two ideal TMDs (using the reported experimental material’s properties), which can harvest waste heat at 400 K with efficiencies about 7% to 8%. To our best knowledge, this design is the first in combining the advantages of graphene electrodes and TMDs to function as a thermionic-based device. PMID:28387363

  13. Overall energy conversion efficiency of a photosynthetic vesicle

    PubMed Central

    Sener, Melih; Strumpfer, Johan; Singharoy, Abhishek; Hunter, C Neil; Schulten, Klaus

    2016-01-01

    The chromatophore of purple bacteria is an intracellular spherical vesicle that exists in numerous copies in the cell and that efficiently converts sunlight into ATP synthesis, operating typically under low light conditions. Building on an atomic-level structural model of a low-light-adapted chromatophore vesicle from Rhodobacter sphaeroides, we investigate the cooperation between more than a hundred protein complexes in the vesicle. The steady-state ATP production rate as a function of incident light intensity is determined after identifying quinol turnover at the cytochrome bc1 complex (cytb⁢c1) as rate limiting and assuming that the quinone/quinol pool of about 900 molecules acts in a quasi-stationary state. For an illumination condition equivalent to 1% of full sunlight, the vesicle exhibits an ATP production rate of 82 ATP molecules/s. The energy conversion efficiency of ATP synthesis at illuminations corresponding to 1%–5% of full sunlight is calculated to be 0.12–0.04, respectively. The vesicle stoichiometry, evolutionarily adapted to the low light intensities in the habitat of purple bacteria, is suboptimal for steady-state ATP turnover for the benefit of protection against over-illumination. DOI: http://dx.doi.org/10.7554/eLife.09541.001 PMID:27564854

  14. Hierarchically structured carbon nanotubes for energy conversion and storage

    NASA Astrophysics Data System (ADS)

    Du, Feng

    As the world population continues to increase, large amounts of energy are consumed. Reality pushes us to find new energy or use our current energy more efficiently. Researches on energy conversion and storage have become increasingly important and essential. This grand challenge research has led to a recent focus on nanostructured materials. Carbon nanomaterials such as carbon nanotubes (CNTs) play a critical role in all of these nanotechnology challenges. CNTs have a very large surface area, a high electrochemical accessibility, high electronic conductivity and strong mechanical properties. This combination of properties makes them promising materials for energy device applications, such as FETs, supercapacitors, fuel cells, and lithium batteries. This study focuses on exploring the possibility of using vertically aligned carbon nanotubes (VA-CNTs) as the electrode materials in these energy applications. For the application of electrode materials, electrical conductive, vertically aligned CNTs with controllable length and diameter were synthesized. Several CVD methods for VA-CNT growth have been explored, although the iron / aluminum pre-coated catalyst CVD system was the main focus. A systematic study of several factors, including growth time, temperature, gas ratio, catalyst coating was conducted. The mechanism of VA-CNTs was discussed and a model for VA-CNT length / time was proposed to explain the CNT growth rate. Furthermore, the preferential growth of semiconducting (up to 96 atom% carbon) VA-SWNTs by using a plasma enhanced CVD process combined with fast heating was also explored, and these semiconducting materials have been directly used for making FETs using simple dispersion in organic solvent, without any separation and purification. Also, by inserting electron-accepting nitrogen atoms into the conjugated VA-CNT structure during the growth process, we synthesized vertically aligned nitrogen containing carbon nanotubes (VA-NCNTs). After purification of

  15. Electrolyte- and Transport-Enhanced Thermogalvanic Energy Conversion

    NASA Astrophysics Data System (ADS)

    Gunawan, Andrey

    Waste heat energy conversion remains an inviting subject for research, given the renewed emphasis on energy efficiency and carbon emissions reduction. Solid-state thermoelectric devices have been widely investigated, but their practical application remains challenging because of cost and the inability to fabricate them in geometries that are easily compatible with heat sources. An intriguing alternative to solid-state thermoelectric devices is thermogalvanic cells, which include a generally liquid electrolyte that permits the transport of ions. Thermogalvanic cells have long been known in the electrochemistry community, but have not received much attention from the thermal transport community. This is surprising given that their performance is highly dependent on controlling both thermal and mass (ionic) transport. This research will focus on a research project, which is an interdisciplinary collaboration between mechanical engineering (i.e. thermal transport) and chemistry, and is a largely experimental effort aimed at improving fundamental understanding of thermogalvanic systems. The first part will discuss how a simple utilization of natural convection within the cell doubles the maximum power output of the cell. In the second part of the research, some of the results from the previous part will be applied in a feasibility study of incorporating thermogalvanic waste heat recovery systems into automobiles. Finally, a new approach to enhance Seebeck coefficient by tuning the configurational entropy of a mixed-ligand complex formation of copper sulfate aqueous electrolytes will be presented. Ultimately, a summary of these results as well as possible future work that can be formed from these efforts is discussed.

  16. A water-swap reaction coordinate for the calculation of absolute protein-ligand binding free energies.

    PubMed

    Woods, Christopher J; Malaisree, Maturos; Hannongbua, Supot; Mulholland, Adrian J

    2011-02-07

    The accurate prediction of absolute protein-ligand binding free energies is one of the grand challenge problems of computational science. Binding free energy measures the strength of binding between a ligand and a protein, and an algorithm that would allow its accurate prediction would be a powerful tool for rational drug design. Here we present the development of a new method that allows for the absolute binding free energy of a protein-ligand complex to be calculated from first principles, using a single simulation. Our method involves the use of a novel reaction coordinate that swaps a ligand bound to a protein with an equivalent volume of bulk water. This water-swap reaction coordinate is built using an identity constraint, which identifies a cluster of water molecules from bulk water that occupies the same volume as the ligand in the protein active site. A dual topology algorithm is then used to swap the ligand from the active site with the identified water cluster from bulk water. The free energy is then calculated using replica exchange thermodynamic integration. This returns the free energy change of simultaneously transferring the ligand to bulk water, as an equivalent volume of bulk water is transferred back to the protein active site. This, directly, is the absolute binding free energy. It should be noted that while this reaction coordinate models the binding process directly, an accurate force field and sufficient sampling are still required to allow for the binding free energy to be predicted correctly. In this paper we present the details and development of this method, and demonstrate how the potential of mean force along the water-swap coordinate can be improved by calibrating the soft-core Coulomb and Lennard-Jones parameters used for the dual topology calculation. The optimal parameters were applied to calculations of protein-ligand binding free energies of a neuraminidase inhibitor (oseltamivir), with these results compared to experiment. These

  17. Solid State NMR Studies of Energy Conversion and Storage Materials

    NASA Astrophysics Data System (ADS)

    Jankuru Hennadige, Sohan Roshel De Silva

    NMR (Nuclear magnetic resonance) spectroscopy is utilized to study energy conversion and storage materials. Different types of NMR techniques including Magic Angle Spinning, Cross-polarization and relaxation measurement experiments were employed. Four different projects are discussed in this dissertation. First, three types of CFx battery materials were investigated. Electrochemical studies have demonstrated different electrochemical performances by one type, delivering superior performance over the other two. 13C and 19F MAS NMR techniques are employed to identify the atomic/molecular structural factors that might account for differences in electrochemical performance among different types. Next as the second project, layered polymer dielectrics were investigated by NMR. Previous studies have shown that thin film capacitors are improved by using alternate layers of two polymers with complementary properties: one with a high breakdown strength and one with high dielectric constant as opposed to monolithic layers. 13C to 1H cross-polarization techniques were used to investigate any inter-layer properties that may cause the increase in the dielectric strength. The third project was to study two types of thermoelectric materials. These samples were made of heavily doped phosphorous and boron in silicon by two different methods: ball-milled and annealed. These samples were investigated by NMR to determine the degree of disorder and obtain insight into the doping efficiency. The last ongoing project is on a lithium-ion battery system. The nature of passivating layers or the solid electrolyte interphase (SEI) formed on the electrodes surface is important because of the direct correlation between the SEI and the battery life time/durability. Multinuclear (7Li, 19F, 31P) techniques are employed to identify the composition of the SEI formation of both positive and negative electrodes.

  18. Electrostatic MEMS vibration energy harvester for HVAC applications with impact-based frequency up-conversion

    NASA Astrophysics Data System (ADS)

    Oxaal, J.; Hella, M.; Borca-Tasciuc, D.-A.

    2016-12-01

    This paper reports on electrostatic MEMS vibration energy harvesters with gap-closing interdigitated electrodes, designed for and tested on HVAC air ducts. The harvesters were fabricated on SOI wafers with 200 µm device layer using a custom microfabrication process. Designs with aspects ratio (electrodes’ gap versus depth) of 10 and 20 were implemented, while the overall footprint was approximately 1 cm  ×  1 cm in both cases. In order to enhance the power output, a dual-level physical stopper system was designed to control the minimum gap between the electrodes, which is a key parameter in the conversion process. The dual-level stopper utilizes cantilever beams to absorb a portion of the impact energy as the electrodes approach the impact point, and a film of parylene with nanometer thickness deposited on the electrode sidewalls. The parylene layer defines the absolute minimum gap and provides electrical insulation. The fabricated devices were first tested on a vibration shaker to characterize the resonant behavior. Devices with aspect ratio 10 were found to exhibit frequency up-conversion, which enhances the amount of converted power. Devices with both aspect ratios were found to exhibits spring hardening due to impact with the stoppers and spring softening behavior at increasing voltage bias. The highest power measured on shaker table for sinusoidal vibrations was 3.13 µW (includes enhancement due to frequency up-conversion driven by impact) for aspect ratio 10, and 0.166 µW for aspect ratio 20. The corresponding dimensional figure-of-merit, defined as the power output normalized to vibration acceleration and frequency, squared voltage and device mass, was in the range of 10 · 10-8 m V-2 for both devices, about an order of magnitude higher than state-of-the-art. Testing was carried out on HVAC air duct vibrating with an RMS acceleration of 155 mg RMS, a primary frequency of 60 Hz and a PSD of 7.15 · 10-2 g2 Hz-1. The peak power measured was

  19. Green farming systems for the Southeast USA using manure-to-energy conversion platforms

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Livestock operations in the Southeastern USA are faced with implementing holistic solutions to address effective manure treatment through efficient energy management and safeguarding of supporting natural resources. By integrating waste-to-energy conversion platforms, future green farming systems ca...

  20. Discovering Inexpensive, Effective Catalysts for Solar Energy Conversion: An Authentic Research Laboratory Experience

    ERIC Educational Resources Information Center

    Shaner, Sarah E.; Hooker, Paul D.; Nickel, Anne-Marie; Leichtfuss, Amanda R.; Adams, Carissa S.; de la Cerda, Dionisia; She, Yuqi; Gerken, James B.; Pokhrel, Ravi; Ambrose, Nicholas J.; Khaliqi, David; Stahl, Shannon S.; Schuttlefield Christus, Jennifer D.

    2016-01-01

    Electrochemical water oxidation is a major focus of solar energy conversion efforts. A new laboratory experiment has been developed that utilizes real-time, hands-on research to discover catalysts for solar energy conversion. The HARPOON, or Heterogeneous Anodes Rapidly Perused for Oxygen Overpotential Neutralization, experiment allows an array of…

  1. Effect of biomass feedstock chemical and physical properties on energy conversion processes: Volume 1, Overview

    SciTech Connect

    Butner, R.S.; Elliott, D.C.; Sealock, L.J. Jr.; Pyne, J.W.

    1988-12-01

    Pacific Northwest Laboratory has completed an initial investigation of the effects of physical and chemical properties of biomass feedstocks relative to their performance in biomass energy conversion systems. Both biochemical conversion routes (anaerobic digestion and ethanol fermentation) and thermochemical routes (combustion, pyrolysis, and gasification) were included in the study. Related processes including chemical and physical pretreatment to improve digestibility, and size and density modification processes such as milling and pelletizing were also examined. This overview report provides background and discussion of feedstock and conversion relationships, along with recommendations for future research. The recommendations include (1) coordinate production and conversion research programs; (2) quantify the relationship between feedstock properties and conversion priorities; (3) develop a common framework for evaluating and characterizing biomass feedstocks; (4) include conversion effects as part of the criteria for selecting feedstock breeding programs; and (5) continue emphasis on multiple feedstock/conversion options for biomass energy systems. 9 refs., 3 figs., 2 tabs.

  2. Energy conversion mechanism for electron perpendicular energy in high guide-field reconnection

    NASA Astrophysics Data System (ADS)

    Guo, X.; Horiuchi, R.; Cheng, C. Z.; Kaminou, Y.; Ono, Y.

    2017-03-01

    The energy conversion mechanism for electron perpendicular energy, both the thermal and the kinetic energies, is investigated by means of two-dimensional, full-particle simulations in an open system. It is shown that electron perpendicular heating is mainly due to the breaking of magnetic moment conservation in separatrix region because the charge separation generates intense variation of electric field within the several electron Larmor radii. Meanwhile, electron perpendicular acceleration takes place mainly due to the polarization drift term as well as the curvature drift term of E .u⊥ in the downstream near the X-point. The enhanced electric field due to the charge separation there results in a significant effect of the polarization drift term on the dissipation of magnetic energy within the ion inertia length in the downstream.

  3. Energy Conversion Mechanism for Electron Perpendicular Energy in High Guide-Field Reconnection

    NASA Astrophysics Data System (ADS)

    Guo, Xuehan; Horiuchi, Ritoku; Kaminou, Yasuhiro; Cheng, Frank; Ono, Yasushi

    2016-10-01

    The energy conversion mechanism for electron perpendicular energy, both the thermal and the kinetic energy, is investigated by means of two-dimensional, full-particle simulations in an open system. It is shown that electron perpendicular heating is mainly due to the breaking of magnetic moment conservation in separatrix region because the charge separation generates intense variation of electric field within the electron Larmor radius. Meanwhile, electron perpendicular acceleration takes place manly due to the polarization drift term as well as the curvature drift term of E . u⊥ in the downstream near the X-point. The enhanced electric field due to the charge separation there results in a significant effect of the polarization drift term on the dissipation of magnetic energy within the ion inertia length in the downstream. Japan Society for the Promotion of Science (JSPS) Fellows 15J03758.

  4. Absolute Beam Energy Measurement using Elastic ep Scattering at Thomas Jefferson National Accelerator Facility

    NASA Astrophysics Data System (ADS)

    Deur, Alexandre

    1999-10-01

    The Jefferson Lab beam energy measurement in Hall A using the elastic ep scattering will be described. This new, non-magnetic, energy measurement method allows a ( triangle E/E=10-4 ) precision. First-order corrections are canceled by the measurements of the electron and proton scattering angles for two symmetric kinematics. The measurement principle will be presented as well as the device and measurement results. Comparison with independent magnetic energy measurements of the same accuracy will be shown. This project is the result of a collaboration between the LPC: université Blaise Pascal/in2p3), Saclay and Jefferson Lab.

  5. Absolute differential cross sections for the elastic scattering of electrons from atomic hydrogen at low incident energies

    NASA Astrophysics Data System (ADS)

    James, Kenneth; Leonard, Linda; Proctor, Stephanie; Childers, J. G.; Khakoo, Murtadha A.

    2003-05-01

    Absolute differential cross sections for electrons elastically scattered from atomic hydrogen have been measured at low incident energies. The measurements were facilitated by the moveable nozzle source recently developed in our lab. Data taken at the incident energies of 20 eV, 40 eV, and 100 eV, and spanning the angular range of 10^rc to 120^rc will be presented. The results will be compared to the earlier measurements of Williams(Joseph Callaway and J. F. Williams, Phys. Rev. A) 12, 2312 (1975), J. F. Williams, J. Phys. B 8, 2191 (1975) and Shyn(T. W. Shyn and S. Y. Cho, Phys. Rev. A) 40, 1315 (1989), T. W. Shyn and Alan Grafe, Phys. Rev. A 46, 2949 (1992), and the theoretical calculations of Bray(Igor Bray, Phys. Rev. A) 46, 6995 (1992). Funded by the National Science Foundation under Grant # NSF-RUI-PHY-0096808.

  6. A 20-KW Wind Energy Conversion System (WECS) at the Marine Corps Air Station, Kaneohe, Hawaii.

    DTIC Science & Technology

    1983-01-01

    NATIONAL BURLAU OF STANDARDS I963 A TN NO: N-1655 A 20-KW WIND ENERGY CONVERSION SYSTEM TITLE: (WECS) AT THE MARINE CORPS AI& STATION, KANEOHE, HAWAII...4 TITLE (o, S,,bIII1. S TYPE OF kEPORT II PERIOD COvERED A 20-KW WIND ENERGY CONVERSION SYSTEM Not final;Sep 78- Dec81 (WECS) AT THE MARINE CORPS AIR...from RepO) 18 SUPPLEMENTARY NOTES • -1 19 KEY WORDS eComf-Ur o, ,e . s d. it ,e f , &1d Ide-,fs by bd, umb,) Wind energy conversion systems, wind energy , wind

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

    SciTech Connect

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

    1998-09-01

    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.

  8. Photochemistry of Inorganic Nanomaterials for Solar Energy Conversion

    NASA Astrophysics Data System (ADS)

    Shelton, Timothy L.

    As our world's population is constantly growing, so also is the need to power the growth and spread of technology. The conversion of abundant solar energy into useable sources of fuel is an area of significant and vital research. Photocatalytic water splitting via suspended nanomaterials or photoelectrochemical cells has great promise for this purpose. This research focuses on the preparation and analysis of nanomaterials utilizing simple methods and earth abundant chemicals that will lead to cost-competitive methods to convert solar energy into an easily stored and transported fuel source. Specifically, our research seeks to better understand the methods of charge generation and separation in nanomaterial films and to quantify the limits of activity in suspended photocatalysts. Chapter 2 introduces a study on the nature of photovoltage generation in well-ordered hematite films under zero applied bias. The thickness of Fe 2O3 nanorod films is varied by a simple hydrothermal synthesis and confirmed with TEM and profilometry measurements. Surface photovoltage spectroscopy (SPS) in the presence of air, water, nitrogen, oxygen, and under vacuum confirms photovoltages are associated with oxidation of surface water and hydroxyl groups and with reversible surface hole trapping on the 1 minute time scale and de-trapping on the 1 hour time scale with a maximum photovoltage of -130 mW under 2.0 eV - 4.5 eV illumination. Sacrificial donors (KI, H2O2, KOH) increase the voltage to -240 and -400 mW, due to improved hole transfer. The photovoltage is quenched with the addition of co-catalysts CoOx and Co-Pi, possibly due to the removal of surface states and enhanced e/h recombination. Chapter 3 outlines a methodical exploration of the limits of water oxidation from illuminated beta-FeO(OH) suspensions. Well-defined akaganeite nanocrystals are able to produce oxygen gas from aqueous solutions in the presence of an appropriate electron acceptor. Optimal conditions were achieved by

  9. A Technique to Measure Energy Partitioning and Absolute Gas Pressures of Strombolian Explosions Using Doppler Radar at Erebus Volcano

    NASA Astrophysics Data System (ADS)

    Gerst, A.; Hort, M.; Kyle, P. R.; Voege, M.

    2008-12-01

    In 2005/06 we deployed three 24GHz (K-Band) continuous wave Doppler radar instruments at the crater rim of Erebus volcano in Antarctica. At the time there was a ~40 m wide, ~1000°C hot convecting phonolite lava lake, which was the source of ~0-6 Strombolian gas bubble explosions per day. We measured the velocities of ~50 explosions using a sample rate of 1-15 Hz. Data were downloaded in real-time through a wireless network. The measurements provide new insights into the still largely unknown mechanism of Strombolian eruptions, and help improve existing eruption models. We present a technique for a quasi in-situ measurement of the absolute pressure inside an eruption gas bubble. Pressures were derived using a simple eruption model and measured high resolution bubble surface velocities during explosions. Additionally, this technique allows us to present a comprehensive energy budget of a volcanic explosion as a time series of all important energy terms (i.e. potential, kinetic, dissipative, infrasonic, surface, seismic and thermal energy output). The absolute gas pressure inside rising expanding gas bubbles rapidly drops from ~3-10 atm (at the time when the lake starts to bulge) to ~1 atm before the bubble bursts, which usually occurs at radii of ~15-20m. These pressures are significantly lower than previously assumed for such explosions. The according internal energy of the gas agrees well with the observed total energy output. The results show that large explosions released about 109 to 1010 J each (equivalent to about 200-2000 kg of TNT), at a peak discharge rate frequently exceeding 109 W (the power output of a typical nuclear power plant). This dynamic output is mainly controlled by the kinetic and potential energy of the exploding magma shell, while other energy types were found to be much smaller (with the exception of thermal energy). Remarkably, most explosions at Erebus show two distinct surface acceleration peaks separated by ~0.3 seconds. This suggests

  10. A twisted wire-shaped dual-function energy device for photoelectric conversion and electrochemical storage.

    PubMed

    Sun, Hao; You, Xiao; Deng, Jue; Chen, Xuli; Yang, Zhibin; Chen, Peining; Fang, Xin; Peng, Huisheng

    2014-06-23

    A wire-shaped energy device that can perform photoelectric conversion and electrochemical storage was developed through a simple but effective twisting process. The energy wire exhibited a high energy conversion efficiency of 6.58 % and specific capacitance of 85.03 μF cm(-1) or 2.13 mF cm(-2), and the two functions were alternately realized without sacrificing either performance.

  11. A study of the conversion of ultrasonic energy and their transducers

    NASA Astrophysics Data System (ADS)

    Li, Q. L.; Wu, J.

    2017-01-01

    This paper essay offers a survey of research on interconvertibility of the conversion of ultrasonic energy with other energy, and their transducers, the conversion materials. Furthermore, it mainly gives piezoelectric ultrasonic transducer and piezoelectrical ultrasonic transducer material. Finally, some problems of ultrasonic energy and transducers, especially microelectronic materials and its acoustoelectric devices used for the ultrahigh-frequency (UHF) ultrasonic which need further research are pointed out.

  12. Effects of Biomolecular Flexibility on Alchemical Calculations of Absolute Binding Free Energies.

    PubMed

    Lawrenz, Morgan; Baron, Riccardo; Wang, Yi; McCammon, J Andrew

    2011-06-02

    The independent trajectory thermodynamic integration (IT-TI) approach (Lawrenz et. al J. Chem. Theory. Comput. 2009, 5:1106-1116(1)) for free energy calculations with distributed computing is employed to study two distinct cases of protein-ligand binding: first, the influenza surface protein N1 neuraminidase bound to the inhibitor oseltamivir, and second, the M. tuberculosis enzyme RmlC complexed with the molecule CID 77074. For both systems, finite molecular dynamics (MD) sampling and varied molecular flexibility give rise to IT-TI free energy distributions that are remarkably centered on the target experimental values, with a spread directly related to protein, ligand, and solvent dynamics. Using over 2 μs of total MD simulation, alternative protocols for the practical, general implementation of IT-TI are investigated, including the optimal use of distributed computing, the total number of alchemical intermediates, and the procedure to perturb electrostatics and van der Waals interactions. A protocol that maximizes predictive power and computational efficiency is proposed. IT-TI outperforms traditional TI predictions and allows a straightforward evaluation of the reliability of free energy estimates. Our study has broad implications for the use of distributed computing in free energy calculations of macromolecular systems.

  13. Application of Nuclear Energy to Bitumen Upgrading and Biomass Conversion

    SciTech Connect

    Mamoru Numata; Yasushi Fujimura; Takayuki Amaya; Masao Hori

    2006-07-01

    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)

  14. Formal Estimation of Errors in Computed Absolute Interaction Energies of Protein-ligand Complexes

    PubMed Central

    Faver, John C.; Benson, Mark L.; He, Xiao; Roberts, Benjamin P.; Wang, Bing; Marshall, Michael S.; Kennedy, Matthew R.; Sherrill, C. David; Merz, Kenneth M.

    2011-01-01

    A largely unsolved problem in computational biochemistry is the accurate prediction of binding affinities of small ligands to protein receptors. We present a detailed analysis of the systematic and random errors present in computational methods through the use of error probability density functions, specifically for computed interaction energies between chemical fragments comprising a protein-ligand complex. An HIV-II protease crystal structure with a bound ligand (indinavir) was chosen as a model protein-ligand complex. The complex was decomposed into twenty-one (21) interacting fragment pairs, which were studied using a number of computational methods. The chemically accurate complete basis set coupled cluster theory (CCSD(T)/CBS) interaction energies were used as reference values to generate our error estimates. In our analysis we observed significant systematic and random errors in most methods, which was surprising especially for parameterized classical and semiempirical quantum mechanical calculations. After propagating these fragment-based error estimates over the entire protein-ligand complex, our total error estimates for many methods are large compared to the experimentally determined free energy of binding. Thus, we conclude that statistical error analysis is a necessary addition to any scoring function attempting to produce reliable binding affinity predictions. PMID:21666841

  15. Biomass Conversion Task IV 1987 program of work: International Energy Agency Bioenergy Agreement

    SciTech Connect

    Stevens, D.J.

    1986-12-01

    Biomass is a major, renewable energy resource through out the world, and extensive research is being conducted by many countries on bioenergy technologies. In an effort to improve communications and cooperation in the area of biomass energy, several nations have agreed to a cooperative program of work under the International Energy Agency's Bioenergy Agreement (IEA/BA). Three areas of major importance have been identified including Short Rotation Forestry, Conventional Forestry, and Biomass Conversion. This document describes the 1987 Program of Work for cooperative activities in the area of Biomass Conversion. The background of the cooperation and descriptions of specific conversion projects are presented. Details of activity funding are also provided. 3 tabs.

  16. Solution-Processed Two-Dimensional Metal Dichalcogenide-Based Nanomaterials for Energy Storage and Conversion.

    PubMed

    Cao, Xiehong; Tan, Chaoliang; Zhang, Xiao; Zhao, Wei; Zhang, Hua

    2016-08-01

    The development of renewable energy storage and conversion devices is one of the most promising ways to address the current energy crisis, along with the global environmental concern. The exploration of suitable active materials is the key factor for the construction of highly efficient, highly stable, low-cost and environmentally friendly energy storage and conversion devices. The ability to prepare two-dimensional (2D) metal dichalcogenide (MDC) nanosheets and their functional composites in high yield and large scale via various solution-based methods in recent years has inspired great research interests in their utilization for renewable energy storage and conversion applications. Here, we will summarize the recent advances of solution-processed 2D MDCs and their hybrid nanomaterials for energy storage and conversion applications, including rechargeable batteries, supercapacitors, electrocatalytic hydrogen generation and solar cells. Moreover, based on the current progress, we will also give some personal insights on the existing challenges and future research directions in this promising field.

  17. 1-Octanol/Water Partition Coefficients of n-Alkanes from Molecular Simulations of Absolute Solvation Free Energies.

    PubMed

    Garrido, Nuno M; Queimada, António J; Jorge, Miguel; Macedo, Eugénia A; Economou, Ioannis G

    2009-09-08

    The 1-octanol/water partition coefficient is an important thermodynamic variable usually employed to understand and quantify the partitioning of solutes between aqueous and organic phases. It finds widespread use in many empirical correlations to evaluate the environmental fate of pollutants as well as in the design of pharmaceuticals. The experimental evaluation of 1-octanol/water partition coefficients is an expensive and time-consuming procedure, and thus, theoretical estimation methods are needed, particularly when a physical sample of the solute may not yet be available, such as in pharmaceutical screening. 1-Octanol/water partition coefficients can be obtained from Gibbs free energies of solvation of the solute in both the aqueous and the octanol phases. The accurate evaluation of free energy differences remains today a challenging problem in computational chemistry. In order to study the absolute solvation Gibbs free energies in 1-octanol, a solvent that can mimic many properties of important biological systems, free energy calculations for n-alkanes in the range C1-C8 were performed using molecular simulation techniques, following the thermodynamic integration approach. In the first part of this paper, we test different force fields by evaluating their performance in reproducing pure 1-octanol properties. It is concluded that all-atom force fields can provide good accuracy but at the cost of a higher computational time compared to that of the united-atom force fields. Recent versions of united-atom force fields, such as Gromos and TraPPE, provide satisfactory results and are, thus, useful alternatives to the more expensive all-atom models. In the second part of the paper, the Gibbs free energy of solvation in 1-octanol is calculated for several n-alkanes using three force fields to describe the solutes, namely Gromos, TraPPE, and OPLS-AA. Generally, the results obtained are in excellent agreement with the available experimental data and are of similar

  18. Absolute binding free energy calculations of CBClip host-guest systems in the SAMPL5 blind challenge

    NASA Astrophysics Data System (ADS)

    Lee, Juyong; Tofoleanu, Florentina; Pickard, Frank C.; König, Gerhard; Huang, Jing; Damjanović, Ana; Baek, Minkyung; Seok, Chaok; Brooks, Bernard R.

    2017-01-01

    Herein, we report the absolute binding free energy calculations of CBClip complexes in the SAMPL5 blind challenge. Initial conformations of CBClip complexes were obtained using docking and molecular dynamics simulations. Free energy calculations were performed using thermodynamic integration (TI) with soft-core potentials and Bennett's acceptance ratio (BAR) method based on a serial insertion scheme. We compared the results obtained with TI simulations with soft-core potentials and Hamiltonian replica exchange simulations with the serial insertion method combined with the BAR method. The results show that the difference between the two methods can be mainly attributed to the van der Waals free energies, suggesting that either the simulations used for TI or the simulations used for BAR, or both are not fully converged and the two sets of simulations may have sampled difference phase space regions. The penalty scores of force field parameters of the 10 guest molecules provided by CHARMM Generalized Force Field can be an indicator of the accuracy of binding free energy calculations. Among our submissions, the combination of docking and TI performed best, which yielded the root mean square deviation of 2.94 kcal/mol and an average unsigned error of 3.41 kcal/mol for the ten guest molecules. These values were best overall among all participants. However, our submissions had little correlation with experiments.

  19. Absolute binding free energy calculations of CBClip host-guest systems in the SAMPL5 blind challenge.

    PubMed

    Lee, Juyong; Tofoleanu, Florentina; Pickard, Frank C; König, Gerhard; Huang, Jing; Damjanović, Ana; Baek, Minkyung; Seok, Chaok; Brooks, Bernard R

    2017-01-01

    Herein, we report the absolute binding free energy calculations of CBClip complexes in the SAMPL5 blind challenge. Initial conformations of CBClip complexes were obtained using docking and molecular dynamics simulations. Free energy calculations were performed using thermodynamic integration (TI) with soft-core potentials and Bennett's acceptance ratio (BAR) method based on a serial insertion scheme. We compared the results obtained with TI simulations with soft-core potentials and Hamiltonian replica exchange simulations with the serial insertion method combined with the BAR method. The results show that the difference between the two methods can be mainly attributed to the van der Waals free energies, suggesting that either the simulations used for TI or the simulations used for BAR, or both are not fully converged and the two sets of simulations may have sampled difference phase space regions. The penalty scores of force field parameters of the 10 guest molecules provided by CHARMM Generalized Force Field can be an indicator of the accuracy of binding free energy calculations. Among our submissions, the combination of docking and TI performed best, which yielded the root mean square deviation of 2.94 kcal/mol and an average unsigned error of 3.41 kcal/mol for the ten guest molecules. These values were best overall among all participants. However, our submissions had little correlation with experiments.

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

    SciTech Connect

    Stevens, D.J.

    1987-12-01

    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.

  1. Relationship between thermoelectric figure of merit and energy conversion efficiency

    PubMed Central

    Kim, Hee Seok; Liu, Weishu; Chen, Gang; Chu, Ching-Wu; Ren, Zhifeng

    2015-01-01

    The formula for maximum efficiency (ηmax) of heat conversion into electricity by a thermoelectric device in terms of the dimensionless figure of merit (ZT) has been widely used to assess the desirability of thermoelectric materials for devices. Unfortunately, the ηmax values vary greatly depending on how the average ZT values are used, raising questions about the applicability of ZT in the case of a large temperature difference between the hot and cold sides due to the neglect of the temperature dependences of the material properties that affect ZT. To avoid the complex numerical simulation that gives accurate efficiency, we have defined an engineering dimensionless figure of merit (ZT)eng and an engineering power factor (PF)eng as functions of the temperature difference between the cold and hot sides to predict reliably and accurately the practical conversion efficiency and output power, respectively, overcoming the reporting of unrealistic efficiency using average ZT values. PMID:26100905

  2. Diminiode thermionic energy conversion with lanthanum-hexaboride electrodes

    NASA Technical Reports Server (NTRS)

    Kroeger, E. W.; Bair, V. L.; Morris, J. F.

    1978-01-01

    Thermionic conversion data obtained from a variable gap cesium diminiode with a hot pressed, sintered lanthanum hexaboride emitter and an arc melted lanthanum hexaboride collector are presented. Performance curves cover a range of temperatures: emitter 1500 to 1700 K, collector 750 to 1000 K, and cesium reservoir 370 to 510 K. Calculated values of emitter and collector work functions and barrier index are also given.

  3. Absolute elastic differential electron scattering cross sections in the intermediate energy region. III - SF6 and UF6

    NASA Technical Reports Server (NTRS)

    Srivastava, S. K.; Trajmar, S.; Chutjian, A.; Williams, W.

    1976-01-01

    A recently developed technique has been used to measure the ratios of elastic differential electron scattering cross sections (DCS) for SF6 and UF6 to those of He at electron impact energies of 5, 10, 15, 20, 30, 40, 50, 60, and 75 eV and at scattering angles of 20 to 135 deg. In order to obtain the absolute values of DCS from these ratios, He DCS of McConkey and Preston have been employed in the 20 to 90 deg range. At angles in the 90 to 135 deg range the recently determined cross sections of Srivastava and Trajmar have been utilized. From these DCS, elastic integral and momentum transfer cross sections have been obtained.

  4. Direct conversion of infrared radiant energy for space power applications

    NASA Technical Reports Server (NTRS)

    Finke, R. C.

    1982-01-01

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

  5. Energy-based coordinated control of wind energy conversion system with DFIG

    NASA Astrophysics Data System (ADS)

    Qu, Y. B.; Song, H. H.

    2011-12-01

    This article presents an energy-based coordinated control of machine- and grid-side converters in a wind energy conversion system (WECS) with a doubly-fed induction generator (DFIG) based on the theory of port-controlled Hamiltonian (PCH) system. Taking into account energy transmission in the dual PWM converter rather than treating rectification and inversion as separate parts, an integrated PCH model for the whole WECS was established from physical meanings. And depending on the new model, an energy-based coordinated control approach was proposed to meet the control requirements of the WECS with an additional objective which was to limit the DC-link voltage fluctuation. The approach was applied on a 2MW WECS, and compared with the energy-based respective control strategy using MATLAB/Simulink. The results show that the proposed control approach provides faster dynamic performance since the two converters operate with the knowledge of each other's operating status, and thus is able to smooth the power flow in the DC-link more effectively.

  6. Theoretical comparison of the energy conversion efficiencies of electrostatic energy harvesters

    NASA Astrophysics Data System (ADS)

    Kim, Chang-Kyu

    2017-02-01

    The characteristics of a new type of electrostatic energy harvesting device, called an out-of-plane overlap harvester, are analyzed for the first time. This device utilizes a movable part that vibrates up and down on the surface of a wafer and a changing overlapping area between the vertical comb fingers. This operational principle enables the minimum capacitance to be close to 0 and significantly increases the energy conversion efficiency per unit volume. The characteristics of the out-of-plane overlap harvester, an in-plane gap-closing harvester, and an in-plane overlap harvester are compared in terms of the length, height, and width of the comb finger and the parasitic capacitance. The efficiency is improved as the length or the height increases and as the width or the parasitic capacitance decreases. In every case, the out-of-plane overlap harvester is able to create more energy and is, thus, preferable over other designs. It is also free from collisions between two electrodes caused by random vibration amplitudes and creates more energy from offaxis perturbations. This device, given its small feature size, is expected to provide more energy to various types of wireless electronics devices and to offer high compatibility with other integrated circuits and ease of embedment.

  7. Evaluation of the field-adapted ADMA approach: absolute and relative energies of crambin and derivatives.

    PubMed

    Exner, Thomas E; Mezey, Paul G

    2005-12-21

    A large number of conformations and chemically modified variants of the protein crambin were used to extensively test the field-adapted adjustable density matrix assembler (FA-ADMA) method developed for ab initio quality quantum chemistry computations of proteins and other macromolecules, introduced in an earlier publication. In this method, the fuzzy density matrix fragmentation scheme of the original adjustable density matrix assembler (ADMA) method has been made more efficient by combining it with an approach of using point charges to approximate the effects of additional, distant parts of a given macromolecule in the quantum chemical calculation of each fragment. In this way, smaller parent molecules can be used for fragment generation, while achieving accuracy that can be obtained only with large parent molecules in the original ADMA method. Whereas in both methods the error relative to the Hartree-Fock result can be reduced below any threshold by choosing large enough parent molecules, this can be done more efficiently with the new method. In order to obtain reliable test results for the accuracy obtainable by the new method when compared to conventional Hartree-Fock calculations, we performed a large number of energy calculations for the protein crambin using various conformations available in the Protein Data Bank, various protonation states, and side chain mutations. Additionally, in order to test the performance of the method for protein-solvent interaction studies, the energy changes due to the formation of complexes with ethanol and single and multiple water molecules were investigated.

  8. Nanomaterials of silicides and silicon for energy conversion and storage

    NASA Astrophysics Data System (ADS)

    Szczech, Jeannine Robin

    Our consumption of fossil fuels can be reduced to address the pressing concerns of global climate change by maximizing the efficiency of conversion technologies. Since many of the alternative fuel sources also being examined are intermittent in nature, it is imperative that high capacity and high power density storage devices are also developed. The conversion efficiency of current state-of-the-art thermoelectric materials is too low to meet our needs, but it may be possible to increase the conversion efficiency of thermoelectric materials by moving from the bulk to the nanoscale. The transition metal silicides, including CrSi2, beta-FeSi2 , Mg2Si and MnSi1.7, have been explored as environmentally friendly non-toxic thermoelectric materials. I began my research in the group synthesizing silicide nanowires via chemical vapor transport (CVT), and later expanded my research to include the synthesis of silicide nanocomposites for thermoelectrics and mesoporous silicon nanocomposites for use as high capacity lithium battery electrodes. Nanoscale thermoelectrics and the enhanced thermoelectric figure-of-merit ZT reported by thermoelectric researchers are reviewed in Chapter 1. Chapter 2 reviews the progress being made in the research community with nanoscale and nanostructured silicon battery anodes. The synthesis and characterization of CrSi2 nanowires synthesized via CVT is detailed in Chapter 3, followed by hyperbranched epitaxial FeSi nanostructures exhibiting merohedral twinning in Chapter 4. Nanowires are fundamentally interesting and provide insight into the changes in materials properties compared to the bulk. The synthesis of interesting nanostructured silicide materials are detailed in Chapter 5, where the conversion of diatoms into a nanostructured thermoelectric Mg2Si/MgO nanocomposite that retains the basic diatom structure after conversion is detailed. This reaction was then modified to use mesoporous silica instead of diatoms to reduce the nanocrystalline

  9. Thermodynamic Inefficiency of Conversion of Solar Energy to Work.

    ERIC Educational Resources Information Center

    Adamson, Arthur W.; And Others

    1984-01-01

    Considers the thermodynamic limitation to the efficiency with which light energy can be converted into work, indicating that no single chemical system converting solar energy into useful work can be very efficient. Also indicates that if solar energy is absorbed as heat for heating purposes, it is almost completely used. (JN)

  10. Vapor-deposited porous films for energy conversion

    DOEpatents

    Jankowski, Alan F.; Hayes, Jeffrey P.; Morse, Jeffrey D.

    2005-07-05

    Metallic films are grown with a "spongelike" morphology in the as-deposited condition using planar magnetron sputtering. The morphology of the deposit is characterized by metallic continuity in three dimensions with continuous and open porosity on the submicron scale. The stabilization of the spongelike morphology is found over a limited range of the sputter deposition parameters, that is, of working gas pressure and substrate temperature. This spongelike morphology is an extension of the features as generally represented in the classic zone models of growth for physical vapor deposits. Nickel coatings were deposited with working gas pressures up 4 Pa and for substrate temperatures up to 1000 K. The morphology of the deposits is examined in plan and in cross section views with scanning electron microscopy (SEM). The parametric range of gas pressure and substrate temperature (relative to absolute melt point) under which the spongelike metal deposits are produced appear universal for other metals including gold, silver, and aluminum.

  11. A rare gas optics-free absolute photon flux and energy analyzer for solar and planetary observations

    NASA Technical Reports Server (NTRS)

    Judge, Darrell L.

    1994-01-01

    We have developed a prototype spectrometer for space applications requiring long term absolute EUV photon flux measurements. In this recently developed spectrometer, the energy spectrum of the incoming photons is transformed directly into an electron energy spectrum by taking advantage of the photoelectric effect in one of several rare gases at low pressures. Using an electron energy spectrometer, followed by an electron multiplier detector, pulses due to individual electrons are counted. The overall efficiency of this process can be made essentially independent of gain drifts in the signal path, and the secular degradation of optical components which is often a problem in other techniques is avoided. A very important feature of this approach is its freedom from the problem of overlapping spectral orders that plagues grating EUV spectrometers. An instrument with these features has not been flown before, but is essential to further advances in our understanding of solar EUV flux dynamics, and the coupled dynamics of terrestrial and planetary atmospheres. The detailed characteristics of this optics-free spectrometer are presented in the publications section.

  12. Measurement of Absolute Excitation Cross Sections in Highly-Charged Ions Using Electron Energy Loss and Merged Beams

    NASA Technical Reports Server (NTRS)

    Chutjian, A.; Smith, Steven J.; Lozano, J.

    2002-01-01

    There is increasing emphasis during this decade on understanding energy balance and phenomena observed in high electron temperature plasmas. The UV spectral return from FUSE, the X-ray spectral return from the HETG on Chandra and the LETGS 011 XMM-Newton are just beginning. Line emissions are almost entirely from highly-charged ions (HCIs) of C, N, 0, Ne, Mg, S, Si, Ca, and Fe. The Constellation-X mission will provide X-ray spectroscopy up to photon energies of 0.12 nm (10 keV) where primary line emitters will be HCIs. A variety of atomic parameters are required to model the stellar and solar plasma. These include cross sections for excitation, ionization, charge-exchange, X-ray emission, direct and indirect recombination, lifetimes and branching ratios, and dependences on l, m mixing by external E and B fields. In almost all cases the atomic quantities are calculated, and few comparisons to experiment have been carried out. Collision strengths and Einstein A-values are required to convert the observed spectral intensities to electron temperatures and densities in the stellar plasma. The JPL electron energy-loss and merged beam approach has been used to measure absolute collision strengths in a number of ions, with critical comparison made to the best available theories.

  13. Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 2: Advanced energy conversion systems. Part 1: Open-cycle gas turbines

    NASA Technical Reports Server (NTRS)

    Brown, D. H.; Corman, J. C.

    1976-01-01

    Ten energy conversion systems are defined and analyzed in terms of efficiency. These include: open-cycle gas turbine recuperative; open-cycle gas turbine; closed-cycle gas turbine; supercritical CO2 cycle; advanced steam cycle; liquid metal topping cycle; open-cycle MHD; closed-cycle inert gas MHD; closed-cycle liquid metal MHD; and fuel cells. Results are presented.

  14. Hot electron detectors and energy conversion in the UV and IR

    NASA Astrophysics Data System (ADS)

    Gong, Tao; Krayer, Lisa; Munday, Jeremy N.

    2015-09-01

    Semiconductor materials are well suited for power conversion when the incident photon energy is slightly larger than the bandgap energy of the semiconductor. However, for photons with energy significantly greater than the bandgap energy, power conversion efficiencies are low. Further, for photons with energy below the bandgap energy, the absence of absorption results in no power conversion. Here we describe photon detection and power conversion of both high energy and sub-bandgap photons using hot carrier effects. For the absorption of high-energy photons, excited electrons and holes have excess kinetic energy, which results in the generation of hot electrons and holes. Energy is typically lost through a thermalization process between the carriers and the lattice. However, collection of carriers before thermalization allows for reduced power loss. Devices consisting of a three-layer stack (transparent conductor - insulator - metal) can be used to generate and collect these hot carriers. Alternatively, when a semiconductor is used, photons with energy below the semiconductor bandgap energy generally do not generate electrons and holes; however, hot carrier collection is still possible in semiconductor devices with a metal layer when a Schottky junction is formed at the semiconductor-metal interface. Such structures enable IR detection based on sub-bandgap photon absorption. Combining these concepts, hot carrier generation and collection and be exploited over a large range of incident wavelengths spanning the UV, visible, and IR.

  15. DOE-EFRC Center on Nanostructuring for Efficient Energy Conversion (CNEEC)

    SciTech Connect

    Prinz, Friedrich B.; Bent, Stacey F.

    2015-10-22

    CNEEC’s mission has been to understand how nanostructuring of materials can enhance efficiency for solar energy conversion to produce hydrogen fuel and to solve fundamental cross-cutting problems. The overarching hypothesis underlying CNEEC research was that controlling, synthesizing and modifying materials at the nanometer scale increases the efficiency of energy conversion and storage devices and systems. In this pursuit, we emphasized the development of functional nanostructures that are based primarily on earth abundant and inexpensive materials.

  16. Efficient conversion of solar energy to biomass and electricity.

    PubMed

    Parlevliet, David; Moheimani, Navid Reza

    2014-01-01

    The Earth receives around 1000 W.m(-2) of power from the Sun and only a fraction of this light energy is able to be converted to biomass (chemical energy) via the process of photosynthesis. Out of all photosynthetic organisms, microalgae, due to their fast growth rates and their ability to grow on non-arable land using saline water, have been identified as potential source of raw material for chemical energy production. Electrical energy can also be produced from this same solar resource via the use of photovoltaic modules. In this work we propose a novel method of combining both of these energy production processes to make full utilisation of the solar spectrum and increase the productivity of light-limited microalgae systems. These two methods of energy production would appear to compete for use of the same energy resource (sunlight) to produce either chemical or electrical energy. However, some groups of microalgae (i.e. Chlorophyta) only require the blue and red portions of the spectrum whereas photovoltaic devices can absorb strongly over the full range of visible light. This suggests that a combination of the two energy production systems would allow for a full utilization of the solar spectrum allowing both the production of chemical and electrical energy from the one facility making efficient use of available land and solar energy. In this work we propose to introduce a filter above the algae culture to modify the spectrum of light received by the algae and redirect parts of the spectrum to generate electricity. The electrical energy generated by this approach can then be directed to running ancillary systems or producing extra illumination for the growth of microalgae. We have modelled an approach whereby the productivity of light-limited microalgae systems can be improved by at least 4% through using an LED array to increase the total amount of illumination on the microalgae culture.

  17. Efficient conversion of solar energy to biomass and electricity

    PubMed Central

    2014-01-01

    The Earth receives around 1000 W.m−2 of power from the Sun and only a fraction of this light energy is able to be converted to biomass (chemical energy) via the process of photosynthesis. Out of all photosynthetic organisms, microalgae, due to their fast growth rates and their ability to grow on non-arable land using saline water, have been identified as potential source of raw material for chemical energy production. Electrical energy can also be produced from this same solar resource via the use of photovoltaic modules. In this work we propose a novel method of combining both of these energy production processes to make full utilisation of the solar spectrum and increase the productivity of light-limited microalgae systems. These two methods of energy production would appear to compete for use of the same energy resource (sunlight) to produce either chemical or electrical energy. However, some groups of microalgae (i.e. Chlorophyta) only require the blue and red portions of the spectrum whereas photovoltaic devices can absorb strongly over the full range of visible light. This suggests that a combination of the two energy production systems would allow for a full utilization of the solar spectrum allowing both the production of chemical and electrical energy from the one facility making efficient use of available land and solar energy. In this work we propose to introduce a filter above the algae culture to modify the spectrum of light received by the algae and redirect parts of the spectrum to generate electricity. The electrical energy generated by this approach can then be directed to running ancillary systems or producing extra illumination for the growth of microalgae. We have modelled an approach whereby the productivity of light-limited microalgae systems can be improved by at least 4% through using an LED array to increase the total amount of illumination on the microalgae culture. PMID:24976951

  18. Low temperature radio-chemical energy conversion processes

    SciTech Connect

    Gomberg, H.J.

    1986-11-04

    This patent describes a radio-chemical method of converting radiated energy into chemical energy form comprising the steps of: (a) establishing a starting chemical compound in the liquid phase that chemically reacts endothermically to radiation and heat energy to produce a gaseous and a solid constituent of the compound, (b) irradiating the compound in its liquid phase free of solvents to chemically release therefrom in response to the radiation the gaseous and solid constituents, (c) physically separating the solid and gaseous phase constituents from the liquid, and (d) chemically processing the constituents to recover therefrom energy stored therein by the irradiation step (b).

  19. Solar-thermal conversion and thermal energy storage of graphene foam-based composites

    NASA Astrophysics Data System (ADS)

    Zhang, Lianbin; Li, Renyuan; Tang, Bo; Wang, Peng

    2016-07-01

    Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy the continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a commonly used PCM, paraffin wax. The high macroporosity and low density of the graphene foam allow for high weight fraction of the PCM to be incorporated, which enhances the heat storage capacity of the composite. The interconnected graphene sheets in the composite provide (1) the solar-thermal conversion capability, (2) high thermal conductivity and (3) form stability of the composite. Under light irradiation, the composite effectively collects and converts the light energy into thermal energy, and the converted thermal energy is stored in the PCM and released in an elongated period of time for sustained utilization. This study provides a promising route for sustainable utilization of solar energy.Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy the continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a

  20. Large impact of reorganization energy on photovoltaic conversion due to interfacial charge-transfer transitions.

    PubMed

    Fujisawa, Jun-ichi

    2015-05-14

    Interfacial charge-transfer (ICT) transitions are expected to be a novel charge-separation mechanism for efficient photovoltaic conversion featuring one-step charge separation without energy loss. Photovoltaic conversion due to ICT transitions has been investigated using several TiO2-organic hybrid materials that show organic-to-inorganic ICT transitions in the visible region. In applications of ICT transitions to photovoltaic conversion, there is a significant problem that rapid carrier recombination is caused by organic-inorganic electronic coupling that is necessary for the ICT transitions. In order to solve this problem, in this work, I have theoretically studied light-to-current conversions due to the ICT transitions on the basis of the Marcus theory with density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations. An apparent correlation between the reported incident photon-to-current conversion efficiencies (IPCE) and calculated reorganization energies was clearly found, in which the IPCE increases with decreasing the reorganization energy consistent with the Marcus theory in the inverted region. This activation-energy dependence was systematically explained by the equation formulated by the Marcus theory based on a simple excited-state kinetic scheme. This result indicates that the reduction of the reorganization energy can suppress the carrier recombination and enhance the IPCE. The reorganization energy is predominantly governed by the structural change in the chemical-adsorption moiety between the ground and ICT excited states. This work provides crucial knowledge for efficient photovoltaic conversion due to ICT transitions.

  1. Thermophotovoltaic energy conversion system having a heavily doped n-type region

    DOEpatents

    DePoy, David M.; Charache, Greg W.; Baldasaro, Paul F.

    2000-01-01

    A thermophotovoltaic (TPV) energy conversion semiconductor device is provided which incorporates a heavily doped n-type region and which, as a consequence, has improved TPV conversion efficiency. The thermophotovoltaic energy conversion device includes an emitter layer having first and second opposed sides and a base layer in contact with the first side of the emitter layer. A highly doped n-type cap layer is formed on the second side of the emitter layer or, in another embodiment, a heavily doped n-type emitter layer takes the place of the cap layer.

  2. Information-to-free-energy conversion: Utilizing thermal fluctuations

    PubMed Central

    Toyabe, Shoichi; Muneyuki, Eiro

    2013-01-01

    Maxwell’s demon is a hypothetical creature that can convert information to free energy. A debate that has lasted for more than 100 years has revealed that the demon’s operation does not contradict the laws of thermodynamics; hence, the demon can be realized physically. We briefly review the first experimental demonstration of Maxwell’s demon of Szilard’s engine type that converts information to free energy. We pump heat from an isothermal environment by using the information about the thermal fluctuations of a Brownian particle and increase the particle’s free energy. PMID:27493548

  3. Extragalactic photon-ALP conversion at CTA energies

    NASA Astrophysics Data System (ADS)

    Kartavtsev, A.; Raffelt, G.; Vogel, H.

    2017-01-01

    Magnetic fields in extragalactic space between galaxy clusters may induce conversions between photons and axion-like particles (ALPs), thereby shielding the photons from absorption on the extragalactic background light. For TeV gamma rays, the oscillation length (losc) of the photon-ALP system becomes inevitably of the same order as the coherence length of the magnetic field l and the length over which the field changes significantly (transition length lt) due to refraction on background photons. We derive exact statistical evolution equations for the mean and variance of the photon and ALP transfer functions in the non-adiabatic regime (losc ~ l gg lt). We also make analytical predictions for the transfer functions in the quasi-adiabatic regime (losc ll l, lt). Our results are important in light of the upcoming Cherenkov Telescope Array (CTA), and may also be applied to models with non-zero ALP masses.

  4. Probing the Crystal Structure, Composition-Dependent Absolute Energy Levels, and Electrocatalytic Properties of Silver Indium Sulfide Nanostructures.

    PubMed

    Saji, Pintu; Ganguli, Ashok K; Bhat, Mohsin A; Ingole, Pravin P

    2016-04-18

    The absolute electronic energy levels in silver indium sulfide (AIS) nanocrystals (NCs) with varying compositions and crystallographic phases have been determined by using cyclic voltammetry. Different crystallographic phases, that is, metastable cubic, orthorhombic, monoclinic, and a mixture of cubic and orthorhombic AIS NCs, were studied. The band gap values estimated from the cyclic voltammetry measurements match well with the band gap values calculated from the diffuse reflectance spectra measurements. The AIS nanostructures were found to show good electrocatalytic activity towards the hydrogen evolution reaction (HER). Our results clearly establish that the electronic and electrocatalytic properties of AIS NCs are strongly sensitive to the composition and crystal structure of AIS NCs. Monoclinic AIS was found to be the most active HER electrocatalyst, with electrocatalytic activity that is almost comparable to the MoS2 -based nanostructures reported in the literature, whereas cubic AIS was observed to be the least active of the studied crystallographic phases and compositions. In view of the HER activity and electronic band structure parameters observed herein, we hypothesize that the Fermi energy level of AIS NCs is an important factor that decides the electrocatalytic efficiency of these nanocomposites. The work presented herein, in addition to being the first of its kind regarding the composition and phase-dependence of electrochemical aspects of AIS NCs, also presents a simple solvothermal method for the synthesis of different crystallographic phases with various Ag/In molar ratios.

  5. Absolute energy distribution of hard x rays produced in the interaction of a kilohertz femtosecond laser with tantalum targets

    SciTech Connect

    Gobet, F.; Hannachi, F.; Aleonard, M. M.; Chemin, J. F.; Claverie, G.; Gerbaux, M.; Malka, G.; Scheurer, J. N.; Tarisien, M.; Blasco, F.; Descamps, D.; Dorchies, F.; Fedosejevs, R.; Fourment, C.; Petit, S.; Meot, V.; Morel, P.; Hanvey, S.; Robson, L.; Liesfeld, B.

    2006-09-15

    Previous reports have indicated the anomalous excitation rate for the 6.2 keV nuclear level of {sup 181}Ta in a plasma produced with a femtosecond laser. A detailed characterization of the electrons and x-ray sources produced in such a plasma is required to interpret these results. In a preliminary work, the continuous energy distribution of hard x rays (10-500 keV) produced in the interaction of a kilohertz femtosecond laser beam with a tantalum solid target is investigated in the 3x10{sup 15}-6x10{sup 16} W/cm{sup 2} range of intensity. A sodium iodide detector with appropriate shielding is used. Strong collimation and absorption filters are used to avoid the pileup of photons in the detector. The response function of this setup is calculated with the GEANT3 simulation code. We demonstrate the necessity to quantify the Compton scattered events in the raw spectra in order to restore the absolute x-ray energy distribution.

  6. Doubly Fed Induction Machine Control For Wind Energy Conversion System

    DTIC Science & Technology

    2009-06-01

    Induction Generator (DFIG), Voltage Source Inverter (VSI), Space Vector Modulation (SVM), Wind Turbine, Field Programmable Gate Array ( FPGA ), Wind...basics of using a doubly-fed induction generator (DFIG) to convert the mechanical energy of the wind into useful electrical power that can be used to...thesis covers the basics of using a doubly-fed induction generator (DFIG) to convert the mechanical energy of the wind into useful electrical power

  7. Engineering light: advances in wavelength conversion materials for energy and environmental technologies.

    PubMed

    Cates, Ezra L; Chinnapongse, Stephanie L; Kim, Jae-Hyuk; Kim, Jae-Hong

    2012-11-20

    Upconversion photoluminescence (UC) occurs in optical materials that are capable of absorbing low energy photons and emitting photons of higher energy and shorter wavelength, while downconversion (DC) materials may absorb one high energy photon and emit two of lower energy for quantum yields exceeding unity. These wavelength conversion processes allow us to transform electromagnetic radiation so it may be more effectively utilized by light-capturing devices and materials. Progress in designing more efficient organic and inorganic photochemical conversion systems has initiated a recent surge in attempts to apply these processes for practical uses, including enhancement of many energy and environmental technologies. In this review, we introduce important concepts in UC and DC materials and discuss the current status and challenges toward the application of wavelength conversion to solar cells, photocatalysis, and antimicrobial surfaces.

  8. Solar energy conversion via hot electron internal photoemission in metallic nanostructures: Efficiency estimates

    SciTech Connect

    Leenheer, Andrew J.; Narang, Prineha; Atwater, Harry A.; Lewis, Nathan S.

    2014-04-07

    Collection of hot electrons generated by the efficient absorption of light in metallic nanostructures, in contact with semiconductor substrates can provide a basis for the construction of solar energy-conversion devices. Herein, we evaluate theoretically the energy-conversion efficiency of systems that rely on internal photoemission processes at metal-semiconductor Schottky-barrier diodes. In this theory, the current-voltage characteristics are given by the internal photoemission yield as well as by the thermionic dark current over a varied-energy barrier height. The Fowler model, in all cases, predicts solar energy-conversion efficiencies of <1% for such systems. However, relaxation of the assumptions regarding constraints on the escape cone and momentum conservation at the interface yields solar energy-conversion efficiencies as high as 1%–10%, under some assumed (albeit optimistic) operating conditions. Under these conditions, the energy-conversion efficiency is mainly limited by the thermionic dark current, the distribution of hot electron energies, and hot-electron momentum considerations.

  9. Evaluations of the Absolute and Relative Free Energies for Antidepressant Binding to the Amino Acid Membrane Transporter LeuT with Free Energy Simulations.

    PubMed

    Zhao, Chunfeng; Caplan, David A; Noskov, Sergei Yu

    2010-06-08

    The binding of ligands to protein receptors with high affinity and specificity is central to many cellular processes. The quest for the development of computational models capable of accurately evaluating binding affinity remains one of the main goals of modern computational biophysics. In this work, free energy perturbation/molecular dynamics simulations were used to evaluate absolute and relative binding affinity for three different antidepressants to a sodium-dependent membrane transporter, LeuT, a bacterial homologue of human serotonin and dopamine transporters. Dysfunction of these membrane transporters in mammals has been implicated in multiple diseases of the nervous system, including bipolar disorder and depression. Furthermore, these proteins are key targets for antidepressants including fluoxetine (aka Prozac) and tricyclic antidepressants known to block transport activity. In addition to being clinically relevant, this system, where multiple crystal structures are readily available, represents an ideal testing ground for methods used to study the molecular mechanisms of ligand binding to membrane proteins. We discuss possible pitfalls and different levels of approximation required to evaluate binding affinity, such as the dependence of the computed affinities on the strength of constraints and the sensitivity of the computed affinities to the particular partial charges derived from restrained electrostatic potential fitting of quantum mechanics electrostatic potential. Finally, we compare the effects of different constraint schemes on the absolute and relative binding affinities obtained from free energy simulations.

  10. Study of a wind energy conversion system in New Hampshire

    NASA Astrophysics Data System (ADS)

    Lockwood, J.; Kraft, G.; Pregent, G.; Smukler, L.

    1981-08-01

    Concern over conventional energy costs and supplies is currently strong, particularly in New England region where eighty percent of the total energy is oil based; furthermore, forty percent of this region's total energy is OPEC oil. These figures contrast with national averages of forty-seven and thirteen percent, respectively (1). The quest to develop alternative and renewable energy sources indigenous to New England is understandable in light of these figures. The wind is one such source. The study of wind energy can be divided into three basic areas; these are technical, legal-institutional, and financial. The technical area encompasses collection and analysis of wind data, selection and installation of wind turbines and peripheral equipment, and operation and maintenance. The legal-institutional area encompasses the resolution of such issues as land use policies, power contracts, and state and federal regulations. The financial area encompasses the examination of investment opportunities made available by various site-machine combinations and the selling of such opportunities to the investment community.

  11. Offshore Hydrokinetic Energy Conversion for Onshore Power Generation

    NASA Technical Reports Server (NTRS)

    Jones, Jack A.; Chao, Yi

    2009-01-01

    Design comparisons have been performed for a number of different tidal energy systems, including a fully submerged, horizontal-axis electro-turbine system, similar to Verdant Tidal Turbines in New York's East River, a platform-based Marine Current Turbine, now operating in Northern Ireland's Strangford Narrows, and the Rotech Lunar Energy system, to be installed off the South Korean Coast. A fourth type of tidal energy system studied is a novel JPL/Caltech hydraulic energy transfer system that uses submerged turbine blades which are mechanically attached to adjacent high-pressure pumps, instead of to adjacent electrical turbines. The generated highpressure water streams are combined and transferred to an onshore hydroelectric plant by means of a closed-cycle pipeline. The hydraulic energy transfer system was found to be cost competitive, and it allows all electronics to be placed onshore, thus greatly reducing maintenance costs and corrosion problems. It also eliminates the expenses of conditioning and transferring multiple offshore power lines and of building offshore platforms embedded in the sea floor.

  12. Isothermal separation processes update. Energy Conversion and Utilization Technologies Program

    SciTech Connect

    England, C.

    1984-08-01

    The isothermal processes of membrane separation, supercritical extraction and condensed-phase chromatography were examined using availability analysis, a method which addresses the thermodynamic value of energy as well as its amount. The general approach was to derive equations that identified where energy, expressed in terms of thermodynamic work, is consumed in these processes and how they compare with conventional separation methods. These separation methods are characterized by pure work inputs, chiefly in the form of a pressure drop which supplies the required energy. Equations were derived for the energy requirement in terms of the theories of ideal and regular solutions. This approach is believed to accurately predict the work of separation in terms of the heat of solution and the entropy of mixing. It can form the basis of a convenient calculation method for optimizing membrane and solvent properties for particular applications. Close examination of supercritical extraction found a relatively simple thermodynamic relationship among the thermodynamic properties of the solvent, the entropy of mixing, and the heat of solution. This allows a direct estimate of the work requirements. The actual work, however, is largely due to the requirement to cycle pressure at high levels in this method. Still, the energy requirements are very low, making up for usually high capital costs for equipment. 12 references, 9 figures, 2 tables.

  13. Heat to electricity conversion by cold carrier emissive energy harvesters

    SciTech Connect

    Strandberg, Rune

    2015-12-07

    This paper suggests a method to convert heat to electricity by the use of devices called cold carrier emissive energy harvesters (cold carrier EEHs). The working principle of such converters is explained and theoretical power densities and efficiencies are calculated for ideal devices. Cold carrier EEHs are based on the same device structure as hot carrier solar cells, but works in an opposite way. Whereas a hot carrier solar cell receives net radiation from the sun and converts some of this radiative heat flow into electricity, a cold carrier EEH sustains a net outflux of radiation to the surroundings while converting some of the energy supplied to it into electricity. It is shown that the most basic type of cold carrier EEHs have the same theoretical efficiency as the ideal emissive energy harvesters described earlier by Byrnes et al. In the present work, it is also shown that if the emission from the cold carrier EEH originates from electron transitions across an energy gap where a difference in the chemical potential of the electrons above and below the energy gap is sustained, power densities slightly higher than those given by Byrnes et al. can be achieved.

  14. A universal electromagnetic energy conversion adapter based on a metamaterial absorber

    NASA Astrophysics Data System (ADS)

    Xie, Yunsong; Fan, Xin; Wilson, Jeffrey D.; Simons, Rainee N.; Chen, Yunpeng; Xiao, John Q.

    2014-09-01

    On the heels of metamaterial absorbers (MAs) which produce near perfect electromagnetic (EM) absorption and emission, we propose a universal electromagnetic energy conversion adapter (UEECA) based on MA. By choosing the appropriate energy converting sensors, the UEECA is able to achieve near 100% signal transfer ratio between EM energy and various forms of energy such as thermal, DC electric, or higher harmonic EM energy. The inherited subwavelength dimension and the EM field intensity enhancement can further empower UEECA in many critical applications such as energy harvesting, photoconductive antennas, and nonlinear optics. The principle of UEECA is understood with a transmission line model, which further provides a design strategy that can incorporate a variety of energy conversion devices. The concept is experimentally validated at a microwave frequency with a signal transfer ratio of 96% by choosing an RF diode as the energy converting sensor.

  15. A universal electromagnetic energy conversion adapter based on a metamaterial absorber

    PubMed Central

    Xie, Yunsong; Fan, Xin; Wilson, Jeffrey D.; Simons, Rainee N.; Chen, Yunpeng; Xiao, John Q.

    2014-01-01

    On the heels of metamaterial absorbers (MAs) which produce near perfect electromagnetic (EM) absorption and emission, we propose a universal electromagnetic energy conversion adapter (UEECA) based on MA. By choosing the appropriate energy converting sensors, the UEECA is able to achieve near 100% signal transfer ratio between EM energy and various forms of energy such as thermal, DC electric, or higher harmonic EM energy. The inherited subwavelength dimension and the EM field intensity enhancement can further empower UEECA in many critical applications such as energy harvesting, photoconductive antennas, and nonlinear optics. The principle of UEECA is understood with a transmission line model, which further provides a design strategy that can incorporate a variety of energy conversion devices. The concept is experimentally validated at a microwave frequency with a signal transfer ratio of 96% by choosing an RF diode as the energy converting sensor. PMID:25200005

  16. A universal electromagnetic energy conversion adapter based on a metamaterial absorber.

    PubMed

    Xie, Yunsong; Fan, Xin; Wilson, Jeffrey D; Simons, Rainee N; Chen, Yunpeng; Xiao, John Q

    2014-09-09

    On the heels of metamaterial absorbers (MAs) which produce near perfect electromagnetic (EM) absorption and emission, we propose a universal electromagnetic energy conversion adapter (UEECA) based on MA. By choosing the appropriate energy converting sensors, the UEECA is able to achieve near 100% signal transfer ratio between EM energy and various forms of energy such as thermal, DC electric, or higher harmonic EM energy. The inherited subwavelength dimension and the EM field intensity enhancement can further empower UEECA in many critical applications such as energy harvesting, photoconductive antennas, and nonlinear optics. The principle of UEECA is understood with a transmission line model, which further provides a design strategy that can incorporate a variety of energy conversion devices. The concept is experimentally validated at a microwave frequency with a signal transfer ratio of 96% by choosing an RF diode as the energy converting sensor.

  17. Methods for calculating the absolute entropy and free energy of biological systems based on ideas from polymer physics.

    PubMed

    Meirovitch, Hagai

    2010-01-01

    The commonly used simulation techniques, Metropolis Monte Carlo (MC) and molecular dynamics (MD) are of a dynamical type which enables one to sample system configurations i correctly with the Boltzmann probability, P(i)(B), while the value of P(i)(B) is not provided directly; therefore, it is difficult to obtain the absolute entropy, S approximately -ln P(i)(B), and the Helmholtz free energy, F. With a different simulation approach developed in polymer physics, a chain is grown step-by-step with transition probabilities (TPs), and thus their product is the value of the construction probability; therefore, the entropy is known. Because all exact simulation methods are equivalent, i.e. they lead to the same averages and fluctuations of physical properties, one can treat an MC or MD sample as if its members have rather been generated step-by-step. Thus, each configuration i of the sample can be reconstructed (from nothing) by calculating the TPs with which it could have been constructed. This idea applies also to bulk systems such as fluids or magnets. This approach has led earlier to the "local states" (LS) and the "hypothetical scanning" (HS) methods, which are approximate in nature. A recent development is the hypothetical scanning Monte Carlo (HSMC) (or molecular dynamics, HSMD) method which is based on stochastic TPs where all interactions are taken into account. In this respect, HSMC(D) can be viewed as exact and the only approximation involved is due to insufficient MC(MD) sampling for calculating the TPs. The validity of HSMC has been established by applying it first to liquid argon, TIP3P water, self-avoiding walks (SAW), and polyglycine models, where the results for F were found to agree with those obtained by other methods. Subsequently, HSMD was applied to mobile loops of the enzymes porcine pancreatic alpha-amylase and acetylcholinesterase in explicit water, where the difference in F between the bound and free states of the loop was calculated. Currently

  18. Solar-to-Chemical Energy Conversion with Photoelectrochemical Tandem Cells.

    PubMed

    Sivula, Kevin

    2013-01-01

    Efficiently and inexpensively converting solar energy into chemical fuels is an important goal towards a sustainable energy economy. An integrated tandem cell approach could reasonably convert over 20% of the sun's energy directly into chemical fuels like H2 via water splitting. Many different systems have been investigated using various combinations of photovoltaic cells and photoelectrodes, but in order to be economically competitive with the production of H2 from fossil fuels, a practical water splitting tandem cell must optimize cost, longevity and performance. In this short review, the practical aspects of solar fuel production are considered from the perspective of a semiconductor-based tandem cell and the latest advances with a very promising technology - metal oxide photoelectrochemical tandem cells - are presented.

  19. Complex metal borohydrides: multifunctional materials for energy storage and conversion.

    PubMed

    Mohtadi, Rana; Remhof, Arndt; Jena, Puru

    2016-09-07

    With the limited supply of fossil fuels and their adverse effect on the climate and the environment, it has become a global priority to seek alternate sources of energy that are clean, abundant, and sustainable. While sources such as solar, wind, and hydrogen can meet the world's energy demand, considerable challenges remain to find materials that can store and/or convert energy efficiently. This topical review focuses on one such class of materials, namely, multi-functional complex metal borohydrides that not only have the ability to store sufficient amount of hydrogen to meet the needs of the transportation industry, but also can be used for a new generation of metal ion batteries and solar cells. We discuss the material challenges in all these areas and review the progress that has been made to address them, the issues that still need to be resolved and the outlook for the future.

  20. Complex metal borohydrides: multifunctional materials for energy storage and conversion

    NASA Astrophysics Data System (ADS)

    Mohtadi, Rana; Remhof, Arndt; Jena, Puru

    2016-09-01

    With the limited supply of fossil fuels and their adverse effect on the climate and the environment, it has become a global priority to seek alternate sources of energy that are clean, abundant, and sustainable. While sources such as solar, wind, and hydrogen can meet the world’s energy demand, considerable challenges remain to find materials that can store and/or convert energy efficiently. This topical review focuses on one such class of materials, namely, multi-functional complex metal borohydrides that not only have the ability to store sufficient amount of hydrogen to meet the needs of the transportation industry, but also can be used for a new generation of metal ion batteries and solar cells. We discuss the material challenges in all these areas and review the progress that has been made to address them, the issues that still need to be resolved and the outlook for the future.

  1. Radiant energy collection and conversion apparatus and method

    DOEpatents

    Hunt, A.J.

    The apparatus for collecting radiant energy and converting to alternate energy forms includes a housing having an interior space and a radiation transparent window allowing solar radiation to be received in the interior space of the housing. Means are provided for passing a stream of fluid past the window and for injecting radiation absorbent particles in said fluid stream. The particles absorb the radiation and because of their very large surface area, quickly release the heat to the surrounding fluid stream. The fluid stream particle mixture is heated until the particles vaporize. The fluid stream is then allowed to expand in, for example, a gas turbine to produce mechanical energy. In an aspect of the present invention properly sized particles need not be vaporized prior to the entrance of the fluid stream into the turbine, as the particles will not damage the turbine blades. In yet another aspect of the invention, conventional fuel injectors are provided to inject fuel into the fluid stream to maintain the proper temperature and pressure of the fluid stream should the source of radiant energy be interrupted. In yet another aspect of the invention, an apparatus is provided which includes means for providing a hot fluid stream having hot particles disbursed therein which can radiate energy, means for providing a cooler fluid stream having cooler particles disbursed therein, which particles can absorb radiant energy and means for passing the hot fluid stream adjacent the cooler fluid stream to warm the cooler fluid and cooler particles by the radiation from the hot fluid and hot particles.

  2. Radiant energy collection and conversion apparatus and method

    DOEpatents

    Hunt, Arlon J.

    1982-01-01

    The apparatus for collecting radiant energy and converting same to alternate energy form includes a housing having an interior space and a radiation transparent window allowing, for example, solar radiation to be received in the interior space of the housing. Means are provided for passing a stream of fluid past said window and for injecting radiation absorbent particles in said fluid stream. The particles absorb the radiation and because of their very large surface area, quickly release the heat to the surrounding fluid stream. The fluid stream particle mixture is heated until the particles vaporize. The fluid stream is then allowed to expand in, for example, a gas turbine to produce mechanical energy. In an aspect of the present invention properly sized particles need not be vaporized prior to the entrance of the fluid stream into the turbine, as the particles will not damage the turbine blades. In yet another aspect of the invention, conventional fuel injectors are provided to inject fuel into the fluid stream to maintain the proper temperature and pressure of the fluid stream should the source of radiant energy be interrupted. In yet another aspect of the invention, an apparatus is provided which includes means for providing a hot fluid stream having hot particles disbursed therein which can radiate energy, means for providing a cooler fluid stream having cooler particles disbursed therein, which particles can absorb radiant energy and means for passing the hot fluid stream adjacent the cooler fluid stream to warm the cooler fluid and cooler particles by the radiation from the hot fluid and hot particles.

  3. Solar-thermal conversion and thermal energy storage of graphene foam-based composites.

    PubMed

    Zhang, Lianbin; Li, Renyuan; Tang, Bo; Wang, Peng

    2016-08-14

    Among various utilizations of solar energy, solar-thermal conversion has recently gained renewed research interest due to its extremely high energy efficiency. However, one limiting factor common to all solar-based energy conversion technologies is the intermittent nature of solar irradiation, which makes them unable to stand-alone to satisfy the continuous energy need. Herein, we report a three-dimensional (3D) graphene foam and phase change material (PCM) composite for the seamlessly combined solar-thermal conversion and thermal storage for sustained energy release. The composite is obtained by infiltrating the 3D graphene foam with a commonly used PCM, paraffin wax. The high macroporosity and low density of the graphene foam allow for high weight fraction of the PCM to be incorporated, which enhances the heat storage capacity of the composite. The interconnected graphene sheets in the composite provide (1) the solar-thermal conversion capability, (2) high thermal conductivity and (3) form stability of the composite. Under light irradiation, the composite effectively collects and converts the light energy into thermal energy, and the converted thermal energy is stored in the PCM and released in an elongated period of time for sustained utilization. This study provides a promising route for sustainable utilization of solar energy.

  4. Assessment of dynamic energy conversion systems for radioisotope heat sources

    SciTech Connect

    Thayer, G.R.; Mangeng, C.A.

    1985-06-01

    The use of dynamic conversion systems to convert the heat generated in a 7500 W(t) 90 Sr radioisotopic heat source to electricity is examined. The systems studies were Stirling; Brayton Cycle; three organic Rankines (ORCs) (Barber-Nichols/ORMAT, Sundstrand, and TRW); and an organic Rankine plus thermoelectrics. The systems were ranked for a North Warning System mission using a Los Alamos Multiattribute Decision Theory code. Three different heat source designs were used: case I with a beginning of life (BOL) source temperature of 640 C, case II with a BOL source temperature of 745/sup 0/C, and case III with a BOL source temperature of 945/sup 0/C. The Stirling engine system was the top-ranked system of cases I and II, closely followed by the ORC systems in case I and ORC plus thermoelectrics in case II. The Brayton cycle system was top-ranked for case III, with the Stirling engine system a close second. The use of /sup 238/Pu in heat source sizes of 7500 W(t) was examined and found to be questionable because of cost and material availability and because of additional requirements for analysis of safeguards and critical mass.

  5. An energy decomposition analysis for second-order Møller-Plesset perturbation theory based on absolutely localized molecular orbitals.

    PubMed

    Thirman, Jonathan; Head-Gordon, Martin

    2015-08-28

    An energy decomposition analysis (EDA) of intermolecular interactions is proposed for second-order Møller-Plesset perturbation theory (MP2) based on absolutely localized molecular orbitals (ALMOs), as an extension to a previous ALMO-based EDA for self-consistent field methods. It decomposes the canonical MP2 binding energy by dividing the double excitations that contribute to the MP2 wave function into classes based on how the excitations involve different molecules. The MP2 contribution to the binding energy is decomposed into four components: frozen interaction, polarization, charge transfer, and dispersion. Charge transfer is defined by excitations that change the number of electrons on a molecule, dispersion by intermolecular excitations that do not transfer charge, and polarization and frozen interactions by intra-molecular excitations. The final two are separated by evaluations of the frozen, isolated wave functions in the presence of the other molecules, with adjustments for orbital response. Unlike previous EDAs for electron correlation methods, this one includes components for the electrostatics, which is vital as adjustment to the electrostatic behavior of the system is in some cases the dominant effect of the treatment of electron correlation. The proposed EDA is then applied to a variety of different systems to demonstrate that all proposed components behave correctly. This includes systems with one molecule and an external electric perturbation to test the separation between polarization and frozen interactions and various bimolecular systems in the equilibrium range and beyond to test the rest of the EDA. We find that it performs well on these tests. We then apply the EDA to a halogen bonded system to investigate the nature of the halogen bond.

  6. An energy decomposition analysis for second-order Møller–Plesset perturbation theory based on absolutely localized molecular orbitals

    SciTech Connect

    Thirman, Jonathan Head-Gordon, Martin

    2015-08-28

    An energy decomposition analysis (EDA) of intermolecular interactions is proposed for second-order Møller–Plesset perturbation theory (MP2) based on absolutely localized molecular orbitals (ALMOs), as an extension to a previous ALMO-based EDA for self-consistent field methods. It decomposes the canonical MP2 binding energy by dividing the double excitations that contribute to the MP2 wave function into classes based on how the excitations involve different molecules. The MP2 contribution to the binding energy is decomposed into four components: frozen interaction, polarization, charge transfer, and dispersion. Charge transfer is defined by excitations that change the number of electrons on a molecule, dispersion by intermolecular excitations that do not transfer charge, and polarization and frozen interactions by intra-molecular excitations. The final two are separated by evaluations of the frozen, isolated wave functions in the presence of the other molecules, with adjustments for orbital response. Unlike previous EDAs for electron correlation methods, this one includes components for the electrostatics, which is vital as adjustment to the electrostatic behavior of the system is in some cases the dominant effect of the treatment of electron correlation. The proposed EDA is then applied to a variety of different systems to demonstrate that all proposed components behave correctly. This includes systems with one molecule and an external electric perturbation to test the separation between polarization and frozen interactions and various bimolecular systems in the equilibrium range and beyond to test the rest of the EDA. We find that it performs well on these tests. We then apply the EDA to a halogen bonded system to investigate the nature of the halogen bond.

  7. An energy decomposition analysis for second-order Møller-Plesset perturbation theory based on absolutely localized molecular orbitals

    NASA Astrophysics Data System (ADS)

    Thirman, Jonathan; Head-Gordon, Martin

    2015-08-01

    An energy decomposition analysis (EDA) of intermolecular interactions is proposed for second-order Møller-Plesset perturbation theory (MP2) based on absolutely localized molecular orbitals (ALMOs), as an extension to a previous ALMO-based EDA for self-consistent field methods. It decomposes the canonical MP2 binding energy by dividing the double excitations that contribute to the MP2 wave function into classes based on how the excitations involve different molecules. The MP2 contribution to the binding energy is decomposed into four components: frozen interaction, polarization, charge transfer, and dispersion. Charge transfer is defined by excitations that change the number of electrons on a molecule, dispersion by intermolecular excitations that do not transfer charge, and polarization and frozen interactions by intra-molecular excitations. The final two are separated by evaluations of the frozen, isolated wave functions in the presence of the other molecules, with adjustments for orbital response. Unlike previous EDAs for electron correlation methods, this one includes components for the electrostatics, which is vital as adjustment to the electrostatic behavior of the system is in some cases the dominant effect of the treatment of electron correlation. The proposed EDA is then applied to a variety of different systems to demonstrate that all proposed components behave correctly. This includes systems with one molecule and an external electric perturbation to test the separation between polarization and frozen interactions and various bimolecular systems in the equilibrium range and beyond to test the rest of the EDA. We find that it performs well on these tests. We then apply the EDA to a halogen bonded system to investigate the nature of the halogen bond.

  8. Silicon Schottky photovoltaic diodes for solar energy conversion

    NASA Technical Reports Server (NTRS)

    Anderson, W. A.

    1975-01-01

    Various factors in Schottky barrier solar cell fabrication are evaluated in order to improve understanding of the current flow mechanism and to isolate processing variables that improve efficiency. Results of finger design, substrate resistivity, surface finishing and activation energy studies are detailed. An increased fill factor was obtained by baking of the vacuum system to remove moisture.

  9. Decomposing Fuel Economy and Greenhouse Gas Regulatory Standards in the Energy Conversion Efficiency and Tractive Energy Domain

    SciTech Connect

    Pannone, Greg; Thomas, John F; Reale, Michael; Betz, Brian

    2017-01-01

    The three foundational elements that determine mobile source energy use and tailpipe carbon dioxide (CO2) emissions are the tractive energy requirements of the vehicle, the on-cycle energy conversion efficiency of the propulsion system, and the energy source. The tractive energy requirements are determined by the vehicle's mass, aerodynamic drag, tire rolling resistance, and parasitic drag. Oncycle energy conversion of the propulsion system is dictated by the tractive efficiency, non-tractive energy use, kinetic energy recovery, and parasitic losses. The energy source determines the mobile source CO2 emissions. For current vehicles, tractive energy requirements and overall energy conversion efficiency are readily available from the decomposition of test data. For future applications, plausible levels of mass reduction, aerodynamic drag improvements, and tire rolling resistance can be transposed into the tractive energy domain. Similarly, by combining thermodynamic, mechanical efficiency, and kinetic energy recovery fundamentals with logical proxies, achievable levels of energy conversion efficiency can be established to allow for the evaluation of future powertrain requirements. Combining the plausible levels of tractive energy and on-cycle efficiency provides a means to compute sustainable vehicle and propulsion system scenarios that can achieve future regulations. Using these principles, the regulations established in the United States (U.S.) for fuel consumption and CO2 emissions are evaluated. Fleet-level scenarios are generated and compared to the technology deployment assumptions made during rule-making. When compared to the rule-making assumptions, the results indicate that a greater level of advanced vehicle and propulsion system technology deployment will be required to achieve the model year 2025 U.S. standards for fuel economy and CO2 emissions.

  10. A History of Geothermal Energy Research and Development in the United States. Energy Conversion 1976-2006

    SciTech Connect

    Mines, Gregory L.

    2010-09-01

    This report, the last in a four-part series, summarizes significant research projects performed by the U.S. Department of Energy (DOE) over 30 years to overcome challenges in energy conversion and to make generation of electricity from geothermal resources more cost-competitive.

  11. Electron-Positron Pair Production in Strong Fields Characterized by Conversion Energy

    NASA Astrophysics Data System (ADS)

    Sitiwaldi, Ibrahim; Li, Zi-Liang; Xie, Bai-Song

    2017-01-01

    It is demonstrated that the production mechanism of a pair which is produced from vacuum under an external field can be characterized by its conversion energy, a quantity defined as total mass-energy of this pair. The value of this quantity is checked with quantum field theoretical simulations for several field configurations and it is found that conversion energy can show all the production channels and give the yields of each channel specifically. We detect signatures of effective mass, combination of different photons as well as dynamically assisted Schwinger mechanism and represented more features of these processes in the view of conversion energy. Supported by the National Natural Science Foundation of China under Grant No. 11475026

  12. Scaling the energy conversion rate from magnetic field reconnection to different bodies

    SciTech Connect

    Mozer, F. S.; Hull, A.

    2010-10-15

    Magnetic field reconnection is often invoked to explain electromagnetic energy conversion in planetary magnetospheres, stellar coronae, and other astrophysical objects. Because of the huge dynamic range of magnetic fields in these bodies, it is important to understand energy conversion as a function of magnetic field strength and related parameters. It is conjectured theoretically and shown experimentally that the energy conversion rate per unit area in reconnection scales as the cube of an appropriately weighted magnetic field strength divided by the square root of an appropriately weighted density. With this functional dependence, the energy release in flares on the Sun, the large and rapid variation of the magnetic flux in the tail of Mercury, and the apparent absence of reconnection on Jupiter and Saturn, may be understood. Electric fields at the perihelion of the Solar Probe Plus mission may be tens of V/m.

  13. Energy conversion within infrared plasmonic absorption metamaterials for multi-band resonance

    NASA Astrophysics Data System (ADS)

    Li, Yongqian; Su, Lei; Xu, Xiaolun; Zhang, Chenglin; Wang, Binbin

    2015-05-01

    The energy conversion within the cross-shaped plasmonic absorber metamaterials (PAM) was investigated theoretically and numerically in the infrared range based on the Poynting's theorem of electromagnetic energy. From the microscopic details, the heat generation owing to the electric current accounts for the majority of the energy conversion, while the magnetic resonance plays a negligible role. The PAMs possess three distinct resonant peaks standing independently, which are attributed to the polarization sensitive excitation of plasmonic resonance. Field redistribution and enhancement associated with multiplex resonant electromagnetic wave passing through the PAM medium provided insight into the energy conversion processes inside the nanostructure. The research results will assist the design of novel plasmon enhanced infrared detectors with multiple-band detection.

  14. Potential environmental consequences of ocean thermal energy conversion (OTEC) plants. A workshop

    SciTech Connect

    Walsh, J.J.

    1981-05-01

    The concept of generating electrical power from the temperature difference between surface and deep ocean waters was advanced over a century ago. A pilot plant was constructed in the Caribbean during the 1920's but commercialization did not follow. The US Department of Energy (DOE) earlier planned to construct a single operational 10MWe Ocean Thermal Energy Conversion (OTEC) plant by 1986. However, Public Law P.L.-96-310, the Ocean Thermal Energy Conversion Research, Development and Demonstration Act, and P.L.-96-320, the Ocean Thermal Energy Conversion Act of 1980, now call for acceleration of the development of OTEC plants, with capacities of 100 MWe in 1986, 500 MWe in 1989, and 10,000 MWe by 1999 and provide for licensing and permitting and loan guarantees after the technology has been demonstrated.

  15. Understanding Power Electronics and Electrical Machines in Multidisciplinary Wind Energy Conversion System Courses

    ERIC Educational Resources Information Center

    Duran, M. J.; Barrero, F.; Pozo-Ruz, A.; Guzman, F.; Fernandez, J.; Guzman, H.

    2013-01-01

    Wind energy conversion systems (WECS) nowadays offer an extremely wide range of topologies, including various different types of electrical generators and power converters. Wind energy is also an application of great interest to students and with a huge potential for engineering employment. Making WECS the main center of interest when teaching…

  16. Chemical Expansion: Implications for Electrochemical Energy Storage and Conversion Devices

    NASA Astrophysics Data System (ADS)

    Bishop, S. R.; Marrocchelli, D.; Chatzichristodoulou, C.; Perry, N. H.; Mogensen, M. B.; Tuller, H. L.; Wachsman, E. D.

    2014-07-01

    Many energy-related materials rely on the uptake and release of large quantities of ions, for example, Li+ in batteries, H+ in hydrogen storage materials, and O2- in solid-oxide fuel cell and related materials. These compositional changes often result in large volumetric dilation of the material, commonly referred to as chemical expansion. This article reviews the current knowledge of chemical expansion and aspires to facilitate and promote future research in this field by providing a taxonomy for its sources, along with recent atomistic insights of its origin, aided by recent computational modeling and an overview of factors impacting chemical expansion. We discuss the implications of chemical expansion for mechanical stability and functionality in the energy applications above, as well as in other oxide-based systems. The use of chemical expansion as a new means to probe other materials properties, as well as its contribution to recently investigated electromechanical coupling, is also highlighted.

  17. Artificial light-harvesting arrays for solar energy conversion.

    PubMed

    Harriman, Anthony

    2015-07-28

    Solar fuel production, the process whereby an energy-rich substance is produced using electrons provided by water under exposure to sunlight, requires the cooperative accumulation of multiple numbers of photons. Identifying the optimum reagents is a difficult challenge, even without imposing the restriction that these same materials must function as both sensitiser and catalyst. The blockade caused by an inadequate supply of photons at the catalytic sites might be resolved by making use of an artificial light-harvesting array whose sole purpose is to funnel photons of appropriate frequency to the active catalyst, which can now be a dark reagent. Here we consider several types of artificial photon collectors built from fluorescent modules interconnected via electronic energy transfer. Emphasis is placed on the materials aspects and on establishing the basic operating principles.

  18. Thermoelectric Energy Conversion Technology for High-Altitude Airships

    NASA Technical Reports Server (NTRS)

    Choi, Sang H.; Elliott, James R.; King, Glen C.; Park, Yeonjoon; Kim, Jae-Woo; Chu, Sang-Hyon

    2011-01-01

    The High Altitude Airship (HAA) has various application potential and mission scenarios that require onboard energy harvesting and power distribution systems. The power technology for HAA maneuverability and mission-oriented applications must come from its surroundings, e.g. solar power. The energy harvesting system considered for HAA is based on the advanced thermoelectric (ATE) materials being developed at NASA Langley Research Center. The materials selected for ATE are silicon germanium (SiGe) and bismuth telluride (Bi2Te3), in multiple layers. The layered structure of the advanced TE materials is specifically engineered to provide maximum efficiency for the corresponding range of operational temperatures. For three layers of the advanced TE materials that operate at high, medium, and low temperatures, correspondingly in a tandem mode, the cascaded efficiency is estimated to be greater than 60 percent.

  19. New approaches to photovoltaic and photoelectrochemical energy conversion

    NASA Astrophysics Data System (ADS)

    Shah, S. Ismat; Lin, Hong-Ying; Miao, Yinghong; Schulz, Meghan E.

    2008-04-01

    In response to skyrocketing fuel costs and evidence of climate change, real technological progress is needed towards harnessing the clean power from the sun to drive human progress. Here we present two approaches to harnessing solar energy currently under investigation in our group. One involves novel photovoltaic cells using different sized quantum dots. Another uses proven photocatalysts to directly electrolyze water, producing hydrogen. The technological background will be discussed, as well as current state of the art and future research direction.

  20. Open cycle ocean thermal energy conversion system structure

    DOEpatents

    Wittig, J. Michael

    1980-01-01

    A generally mushroom-shaped, open cycle OTEC system and distilled water producer which has a skirt-conduit structure extending from the enlarged portion of the mushroom to the ocean. The enlarged part of the mushroom houses a toroidal casing flash evaporator which produces steam which expands through a vertical rotor turbine, partially situated in the center of the blossom portion and partially situated in the mushroom's stem portion. Upon expansion through the turbine, the motive steam enters a shell and tube condenser annularly disposed about the rotor axis and axially situated beneath the turbine in the stem portion. Relatively warm ocean water is circulated up through the radially outer skirt-conduit structure entering the evaporator through a radially outer portion thereof, flashing a portion thereof into motive steam, and draining the unflashed portion from the evaporator through a radially inner skirt-conduit structure. Relatively cold cooling water enters the annular condenser through the radially inner edge and travels radially outwardly into a channel situated along the radially outer edge of the condenser. The channel is also included in the radially inner skirt-conduit structure. The cooling water is segregated from the potable, motive steam condensate which can be used for human consumption or other processes requiring high purity water. The expansion energy of the motive steam is partially converted into rotational mechanical energy of the turbine rotor when the steam is expanded through the shaft attached blades. Such mechanical energy drives a generator also included in the enlarged mushroom portion for producing electrical energy. Such power generation equipment arrangement provides a compact power system from which additional benefits may be obtained by fabricating the enclosing equipment, housings and component casings from low density materials, such as prestressed concrete, to permit those casings and housings to also function as a floating

  1. University Capstone Project: Enhanced Initiation Techniques for Thermochemical Energy Conversion

    DTIC Science & Technology

    2013-03-01

    a hydrocarbon fuel (2-4 mm) [5-7]. As a result, the lean burn region, engine efficiency, and fuel flexibility of such an engine are very constrained...ignition energy. Thirdly, for large molecular hydrocarbon fuels, the mixture Lewis number is so large that the initial ignition kernel is affected...strongly by the enthalpy loss due to flame stretch. Finally, a thermal plasma such as the conventional spark only provides heat and the electron

  2. Performance Optimization of a Pneumatic Wave Energy Conversion Device.

    DTIC Science & Technology

    1982-08-26

    The edges of the internal plexi - glass turbine casing was rounded off to reduce turbulence in the air flow. The turbine was now read-F for the second...As a wave approaches shore it interacts with the sea floor and loses energy due to bottom friction and irrotationalities. The deep water condition...heavier parts had increased the internal friction of the system, and to see if the turbine could handle the effects of greater air flow. For this

  3. New Measurements of the Absolute Spectral Energy Distribution of Solar Radiation in the Range Double Lambda 650-1070 NM

    NASA Astrophysics Data System (ADS)

    Burlov-Vasilev, K. A.; Vasileva, I. E.; Matveev, Yu. B.

    1996-01-01

    Spectral measurements of the solar disk centre intensity for the near-IR region have been made at he Terskol High-Altitude Station in 1992. These measurements are the continuation of the program for the solar absolute spectral energy distribution investigation. Data published earlier are extended to the longwave spectral region up to 1070 nm. The special-purpose solar telescope SEF-1 was used. We compared the disk centre brightness with brightness of the calibrated region of the standard ribbon tungsten lamp. The atmospheric extinction was taken into account by the Bouguer method with simultaneous control of the atmosphere stability. The 1-nm integrals of the disk centre intensity in the range double lamda 650-1070 nm based on 5-day measurements in March-October 1992 are given. The uncertainty of these values is 2%. In regions with strong telluric absorption by oxygen and water-vapour bands, the reductions are made, using synthetic atmospheric absorption spectra computed on the basis of molecular parameter atlas HITRAN and the standard model atmosphere. By the use of the solar limb darkening coefficients the values of the solar flux at 1 A.U. were derived. Our measurements show the best agreement with the data of Makarova, Kharitonov, and Kazachevskaya as well as with the common data from Shaw and Frohlich. For lambda greater than 850 nm our data are systematically lower than the data by Neckel and Labs.

  4. Absolute binding-free energies between standard RNA/DNA nucleobases and amino-acid sidechain analogs in different environments.

    PubMed

    de Ruiter, Anita; Zagrovic, Bojan

    2015-01-01

    Despite the great importance of nucleic acid-protein interactions in the cell, our understanding of their physico-chemical basis remains incomplete. In order to address this challenge, we have for the first time determined potentials of mean force and the associated absolute binding free energies between all standard RNA/DNA nucleobases and amino-acid sidechain analogs in high- and low-dielectric environments using molecular dynamics simulations and umbrella sampling. A comparison against a limited set of available experimental values for analogous systems attests to the quality of the computational approach and the force field used. Overall, our analysis provides a microscopic picture behind nucleobase/sidechain interaction preferences and creates a unified framework for understanding and sculpting nucleic acid-protein interactions in different contexts. Here, we use this framework to demonstrate a strong relationship between nucleobase density profiles of mRNAs and nucleobase affinity profiles of their cognate proteins and critically analyze a recent hypothesis that the two may be capable of direct, complementary interactions.

  5. DAQ Software Contributions, Absolute Scale Energy Calibration and Background Evaluation for the NOvA Experiment at Fermilab

    SciTech Connect

    Flumerfelt, Eric Lewis

    2015-08-01

    The NOvA (NuMI Off-axis ve [nu_e] Appearance) Experiment is a long-baseline accelerator neutrino experiment currently in its second year of operations. NOvA uses the Neutrinos from the Main Injector (NuMI) beam at Fermilab, and there are two main off-axis detectors: a Near Detector at Fermilab and a Far Detector 810 km away at Ash River, MN. The work reported herein is in support of the NOvA Experiment, through contributions to the development of data acquisition software, providing an accurate, absolute-scale energy calibration for electromagnetic showers in NOvA detector elements, crucial to the primary electron neutrino search, and through an initial evaluation of the cosmic background rate in the NOvA Far Detector, which is situated on the surface without significant overburden. Additional support work for the NOvA Experiment is also detailed, including DAQ Server Administration duties and a study of NOvA’s sensitivity to neutrino oscillations into a “sterile” state.

  6. Thermal-to-electric energy conversion using ferroelectric film capacitors

    SciTech Connect

    Kozyrev, A. B.; Platonov, R. A.; Soldatenkov, O. I.

    2014-10-28

    The capacitive ferroelectric thermoelectric converter harvesting electrical energy through non-linear capacitance variation caused by changes in temperature is analyzed. The ferroelectric material used was the thin (0.5 μm) Ba{sub 0.3}Sr{sub 0.7}TiO{sub 3} film. On the basis of experimental dependencies of the ferroelectric film permittivity on temperature ranging from 100 K to 350 K under different electric fields up to 80 V/μm, the optimum values of operating temperatures and electric field for the energy harvesting optimization were determined. For the temperature oscillations of ±15 K around room temperature and electric field about 40 V/μm, the harvested energy was estimated as 30 mJ/cm{sup 3}. It is shown that the use of thin ferroelectric films for rapid capacitance variation versus temperature and microelectromechanical systems for fast temperature modulations may be a relevant solution for creation of small power scale generators for portable electronics.

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

    SciTech Connect

    Mekhiche, Mike; Dufera, Hiz; Montagna, Deb

    2012-10-29

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

  8. Effect of biomass feedstock chemical and physical properties on energy conversion processes: Volume 2, Appendices

    SciTech Connect

    Butner, R.S.; Elliott, D.C.; Sealock, L.J., Jr.; Pyne, J.W.

    1988-12-01

    This report presents an exploration of the relationships between biomass feedstocks and the conversion processes that utilize them. Specifically, it discusses the effect of the physical and chemical structure of biomass on conversion yields, rates, and efficiencies in a wide variety of available or experimental conversion processes. A greater understanding of the complex relationships between these conversion systems and the production of biomass for energy uses is required to help optimize the complex network of biomass production, collection, transportation, and conversion to useful energy products. The review of the literature confirmed the scarcity of research aimed specifically at identifying the effect of feedstock properties on conversion. In most cases, any mention of feedstock-related effects was limited to a few brief remarks (usually in qualitative terms) in the conclusions, or as a topic for further research. Attempts to determine the importance of feedstock parameters from published data were further hampered by the lack of consistent feedstock characterization and the difficulty of comparing results between different experimental systems. Further research will be required to establish quantitative relationships between feedstocks and performance criteria in conversion. 127 refs., 4 figs., 7 tabs.

  9. Investigation of current university research concerning energy conversion and conservation in small single-family dwellings

    NASA Technical Reports Server (NTRS)

    Grossman, G. R.; Roberts, A. S., Jr.

    1975-01-01

    An investigation was made of university research concerning energy conversion and conservation techniques which may be applied in small single-family residences. Information was accumulated through published papers, progress reports, telephone conversations, and personal interviews. A synopsis of each pertinent investigation is given. Finally, a discussion of the synopses is presented and recommendations are made concerning the applicability of concepts for the design and construction of NASA-Langley Research Center's proposed Technology Utilization House in Hampton, Virginia.

  10. Heat Exchanger Cleaning in Support of Ocean Thermal Energy Conversion (OTEC) - Mechanical Subsystem.

    DTIC Science & Technology

    1980-12-01

    Thermal E ergy Conversion ( OTEC ) - Mechanical 416ś Subsyste 7,6. AaM4-"GO. PAORT NUIBER 7. AUTHOR(*) 8. CONTRACT OR GRANT NUMBER(s) Daniel ott 9...for Ocean Thermal Energy Conversion ( OTEC ). Described in the report are the water supply and distribution and the flow driven brush, recirculating...Recirculating Sponge Rubber Balls .. .... ............. 17 Chlorination .. .............. ............. 19 OTEC MAINTENANCE PROCEDURES

  11. High efficiency thermal to electric energy conversion using selective emitters and spectrally tuned solar cells

    NASA Technical Reports Server (NTRS)

    Chubb, Donald L.; Flood, Dennis J.; Lowe, Roland A.

    1992-01-01

    Thermophotovoltaic (TPV) systems are attractive possibilities for direct thermal-to-electric energy conversion, but have typically required the use of black body radiators operating at high temperatures. Recent advances in both the understanding and performance of solid rare-earth oxide selective emitters make possible the use of TPV at temperatures as low as 1500 K. Depending on the nature of parasitic losses, overall thermal-to-electric conversion efficiencies greater than 20 percent are feasible.

  12. Energy Conversion Alternatives Study (ECAS), Westinghouse phase 1. Volume 1: Introduction and summary and general assumptions. [energy conversion systems for electric power plants using coal - feasibility

    NASA Technical Reports Server (NTRS)

    Beecher, D. T.

    1976-01-01

    Nine advanced energy conversion concepts using coal or coal-derived fuels are summarized. They are; (1) open-cycle gas turbines, (2) combined gas-steam turbine cycles, (3) closed-cycle gas turbines, (4) metal vapor Rankine topping, (5) open-cycle MHD; (6) closed-cycle MHD; (7) liquid-metal MHD; (8) advanced steam; and (9) fuel cell systems. The economics, natural resource requirements, and performance criteria for the nine concepts are discussed.

  13. Energy Conversion Alternatives Study (ECAS), General Electric Phase 1. Volume 3: Energy conversion subsystems and components. Part 3: Gasification, process fuels, and balance of plant

    NASA Technical Reports Server (NTRS)

    Boothe, W. A.; Corman, J. C.; Johnson, G. G.; Cassel, T. A. V.

    1976-01-01

    Results are presented of an investigation of gasification and clean fuels from coal. Factors discussed include: coal and coal transportation costs; clean liquid and gas fuel process efficiencies and costs; and cost, performance, and environmental intrusion elements of the integrated low-Btu coal gasification system. Cost estimates for the balance-of-plant requirements associated with advanced energy conversion systems utilizing coal or coal-derived fuels are included.

  14. Energy conversion and fuel production from electrochemical interfaces

    NASA Astrophysics Data System (ADS)

    Markovic, Nenad

    2012-02-01

    Design and synthesis of energy efficient and stable electrochemical interfaces (materials and double layer components) with tailor properties for accelerating and directing chemical transformations is the key to developing new alternative energy systems -- fuel cells, electrolizers and batteries. In aqueous electrolytes, depending on the nature of the reacting species, the supporting electrolyte, and the metal electrodes, two types of interactions have traditionally been considered: (i) direct -- covalent - bond formation between adsorbates and electrodes, involving chemisorption, electron transfer, and release of the ion hydration shell; and (ii) relatively weak non-covalent metal-ion forces that may affect the concentration of ions in the vicinity of the electrode but do not involve direct metal-adsorbate bonding. The range of physical phenomena associated with these two classes of bonds is unusually broad, and are of paramount importance to understand activity of both metal-electrolyte two phase interfaces and metal-Nafion-electrolyte three phase interfaces. Furthermore, in the past, researcher working in the field of fuel cells (converting hydrogen and oxygen into water) and electrolyzers (splitting water back to H2 and O2) ) seldom focused on understanding the electrochemical compliments of these reactions in battery systems, e.g., the lithium-air system. In this lecture, we address the importance of both covalent and non-covalent interactions in controlling catalytic activity at the two-phase and three-phase interfaces. Although the field is still in its infancy, a great deal has already been learned and trends are beginning to emerge that give new insight into the relationship between the nature of bonding interactions and catalytic activity/stability of electrochemical interfaces. In addition, to bridge the gap between the ``water battery'' (fuel cell <-> electrolyzer) and the Li-air battery systems we demonstrate that this would require fundamentally new

  15. Innovative Energy conversion Schemes for Space Based Strategic Defense Systems

    DTIC Science & Technology

    1988-01-01

    energy when and where needed in orbit © Solid oxide regenerative fuel cells have potential for veryhigh power densities - low mass-to-orbit... UO2 ) Natural uranium 95% Pa-210 (radioactive decay) 80% Pu-238 (radioactive decay) Hydrogen (Lower Heating Value) Methane (Lower Heating Value...5.0X104 4.4X104 3.8xl03 9.8xl02 Silver oxide -zinc battery 437 Lead-acid battery 119 Flywheel (uniformly-stressed disk) 79 Compressed gas

  16. New energy conversion techniques in space, applicable to propulsion

    NASA Technical Reports Server (NTRS)

    Hertzberg, A.; Sun, K. C.

    1989-01-01

    The powering of aircraft with laser energy from a solar power satellite may be a promising new approach to the critical problem of the rising cost of fuel for aircraft transportation systems. The result is a nearly fuelless, pollution-free flight transportation system which is cost-competitive with the fuel-conservative airplane of the future. The major components of this flight system include a laser power satellite, relay satellites, laser-powered turbofans and a conventional airframe. The relay satellites are orbiting optical systems which intercept the beam from a power satellite and refocus and redirect the beam to its next target.

  17. Low Cost Solar Energy Conversion (Carbon Cycle 2.0)

    ScienceCinema

    Ramesh, Ramamoorthy

    2016-07-12

    Ramamoorthy Ramesh from LBNL's Materials Science Division speaks at the Carbon Cycle 2.0 kick-off symposium Feb. 2, 2010. We emit more carbon into the atmosphere than natural processes are able to remove - an imbalance with negative consequences. Carbon Cycle 2.0 is a Berkeley Lab initiative to provide the science needed to restore this balance by integrating the Labs diverse research activities and delivering creative solutions toward a carbon-neutral energy future. http://carboncycle2.lbl.gov/

  18. Twisted Savonius turbine based marine current energy conversion system

    NASA Astrophysics Data System (ADS)

    Hassan, Md. Imtiaj

    The Ocean Network Seafloor Instrumentation (ONSFI) Project is a multidisciplinary research and development project that aims to design, fabricate and validate a proof-of-concept seafloor array of wireless marine sensors for use in monitoring seabed processes. The sensor pods, known as Seaformatics, will be powered by ocean bottom currents and will be able to communicate with each other and to the Internet through surface master units to facilitate observation of the ocean floor from the shore. This thesis explores the use of the twisted Savonius turbine as a means of converting the kinetic energy of the free flowing water into electrical energy for the pods. This will eliminate the need for battery replacement. A physical model of the turbine was constructed and tested in the Water Flume at the Marine Institute of Memorial University and in the Wind Tunnel in the Engineering Building at Memorial University. A mathematical model of the turbine was constructed in SolidWorks. This was tested in the Computational Fluid Dynamics or CFD software FLOW-3D. Experimental results were compared with CFD results and the agreement was reasonable. A twisted Savonius turbine emulator was developed to test a dc-dc boost converter. A low cost microcontroller based MPPT algorithm was developed to obtain maximum power from the turbine. Overall the thesis shows that the twisted Savonius turbine can provide the power needed by the sensor pods. It also shows that CFD is a viable way to study the performance of the Savonius type of turbine.

  19. Aluminum rich alloys for energy storage and conversion

    NASA Astrophysics Data System (ADS)

    Choi, Go

    The recent environmental problem and depletion of natural power resources have intensified the search for clean and renewable energy which has become one of the major issues of the Twenty-first century. Furthermore, global demand for freshwater has been increasing, raising concerns for water insufficiency. The goal of this research is to seek and introduce a viable technology that could potentially solve both energy and water crises. It has been investigated that Al-Ga-In-Sn quaternary system alloys can split water and produce hydrogen and heat. This paper focuses on the aluminum-rich Al-Ga-In-Sn quaternary system alloys, exploring the mystery behind the mechanism. As the paper will show, this technology can be applied to both salt water and sea water, and is thus a potential solution for marine applications and desalination. However, it has been shown that the alloy reacts differently depending on the fabrication method and environmental conditions. Various experiments were conducted to understand this phenomenon. This paper discusses several different reactions caused by various cooling rates and compositions, which effectively changes the crystal structure of the alloy and its liquid phase. Characteristics of the liquid phase define the alloy and determine its applications.

  20. Combined chemical looping for energy storage and conversion

    NASA Astrophysics Data System (ADS)

    Galvita, Vladimir V.; Poelman, Hilde; Marin, Guy B.

    2015-07-01

    Combined chemical looping was demonstrated as novel concept of energy storage in a laboratory scale test. The proposed technology is able to store and release energy from redox chemical looping reactions combined with calcium looping. This process uses Fe3O4 and CaO, two low cost and environmentally friendly materials, while CH4 + CO2 serve as feed. During the reduction of Fe3O4 by CH4, both formation of carbon and metallic iron occur. CO2 acts as mediation gas to facilitate the metal/metal oxide redox reaction and carbon gasification into CO. CaO, on the other hand, is used for storage of CO2. Upon temperature rise, CaCO3 releases CO2, which re-oxidizes the carbon deposits and reduced Fe, thus producing carbon monoxide. The amount of produced CO is higher than the theoretical amount for Fe3O4, because carbon deposits from CH4 equally contribute to the CO yield. After each redox cycle, the material is regenerated, so that it can be used repeatedly, providing a stable process.