Energy Technology Data Exchange (ETDEWEB)

We consider the pre-Big-Bang scenario with a massive axion field which starts to dominate energy density when oscillating in an instanton-induced potential and subsequently reheats the universe as it decays into photons, thus creating adiabatic CMB perturbations. We find that the fluctuations in the axion field can give rise to a nearly flat spectrum of adiabatic perturbations with a spectral tilt {delta}n in the range -0.1< or approx. {delta}n < or approx. 1.

International Nuclear Information System (INIS)

A number of systems which can elucidate physics beyond the standard model are investigated. The production of axions by a network of cosmic strings in the early universe is calculated. This allows an upper bound to be placed on the axion decay constant, and provides the preferred Peccei-Quinn symmetry breaking scale for axions to make up the dark matter of the universe. Models of neutrino mass arising from strong interactions are investigated. These models possess a massless up quark, thereby solving the strong CP problem. A systematic analysis of the contributions to time reversal violating atomic and molecular electric dipole moments is presented. Specific contributions from the supersymmetric standard model are calculated. The contributions arising from the QCD vacuum angle are also discussed. Prospects for detecting the axion by its long range coherent force are related to measurable electron dipole ...

Science.gov (United States)

Not Available

Science.gov (United States)

It is shown that there may be a correlation between the galactic cosmic rays and the solar neutrino

International Nuclear Information System (INIS)

We describe exact cosmological solutions with rotation and expansion in the low-energy effective string theory. These models are spatially homogeneous (closed Bianchi type IX) and they belong to the family of shear-free metrics which are causal (no closed timelike curves are allowed), admit no parallax effects and do not disturb the isotropy of the background radiation. The dilaton and the axion fields are nontrivial, in general, and we consider both cases with and without the central charge (effective cosmological constant).

CERN Document Server

Gravitational lensing by the dual cusp catastrophes of the cold dark matter (CDM) caustic rings at cosmological distances may provide the tantalizing opportunity to detect CDM indirectly, and discriminate between axions and weakly interacting massive particles (WIMPs). Caustics are places where the CDM particles are naturally focussed. Our focus is upon the caustic rings which are closed tubes whose cross-section is an elliptic umbilic catastrophe with three dual cusps. A caustic ring has a specific density profile, a specific geometry and, therefore, precisely calculable gravitational lensing signatures. The magnification monotonically increases as the line of sight approaches to the cusps where it diverges in the limit of zero velocity dispersion. In this limit, we find 37% magnification at a sample point near the outer cusps of the CDM caustic rings at cosmological distances. In the presence of finite velocity dispersion, the lower and upper bounds of the ...

CERN Document Server

Solar wind effect on the muon flux at sea level

International Science & Technology Center (ISTC)

Elaboration of Electrochemical Solar Energy Converter Incorporating Cadmium Selenide Semiconductor Developed Electrochemically

Energy Technology Data Exchange (ETDEWEB)

The article is the second part of a review dealing with latest developments in the area of solar cell technologies and application. Physical principles, design and efficiency as well as advantages and disadvantages of GaAs- and CdS-solar cells are described. Power generation solar cell systems with voltage converters, combined solar cell/solar collector systems and thermoelectric solar systems are presented in the second part of the article.

Science.gov (United States)

Education resources dealing with solar-terrestrial physics, solar effects, solar radiation, etc. Includes links to short reference papers on subjects ... ...

Science.gov (United States)

A silicon solar cell assembly comprising a large, thin silicon solar cell bonded to a metal mount for use when there exists a mismatch in the thermal expansivities of the device and the mount.

International Nuclear Information System (INIS)

Physical processes in the region of laser conversion for the next Linear Colliders (NLC) are discussed. The main goal of this conversion is to obtain high-energy intense #gamma# beams for #gamma#e and #gamma##gamma# colliders. This conversion has important by-products: (i) one can observe here effect of nonlinear QED (in a strong external field)-production of e"+e"- pairs by a high-energy photon and emission of very high-energy photons by an electron; (ii) one can produce and observe here the invisible axion in colliding #gamma#_0e beams. The NQED effects also result in variation of the spectra of high-energy photons and an additional background. 12 refs., 12 figs., 1 tab.

Science.gov (United States)

... nent to the design and construction of metal-semiconductor solar cells, in that both the photovoltage and the efficiency of metal-semiconductor cells ...

Energy Technology Data Exchange (ETDEWEB)

The performance of a thermophotovoltaic (TPV) converter for solar energy is compared with that of direct solar energy conversion by silicon and germanium solar cells. The optical selectivity of an intermediate emitter is computed. Experimental results on selective emission, based on selectively emitting materials and on antireflection coatings on metals, are reported. For a TPV converter equipped with silicon solar cells, no selective emitter is found to yield better results than would be obtained by direct conversion. A TPV converter with germanium cells operating with a ThO/sub 2/-coated tungsten emitter, however, may achieve a conversion efficiency superior to that of direct solar energy conversion by either silicon or germanium solar cells.

Energy Technology Data Exchange (ETDEWEB)

The contents include: Detailed index for 1991; Data for November 1991--Solar-terrestrial environment, IUWDS alert periods (advance and worldwide), Solar activity indices, Solar flares, Solar radio emission, Stanford mean solar magnetic field; Data for October 1991--Solar active regions, Sudden ionospheric disturbances, Solar radio spectral observations, Cosmic ray measurements by neutron monitor, Geomagnetic indices; Late data--Cosmic ray measurements by neutron monitor (Climax February and May 1990, Deep River May-August 1991), Geomagnetic indices (Sudden commencements/Solar flare effects January-May 1991); Errata--August 1991 Geomagnetic activity indices.

Energy Technology Data Exchange (ETDEWEB)

Thermal absorption with its combined thermal and mechanical loads in a solar receiver does depend significantly on the distribution of incident solar radiation. For a cavity receiver with paraboloid collectar a method is derived which enables the calculation of solar radiation distribution on the areas inside the receiver. The theoretical bases are presented first, and a subsequent example shows the influence of the most important geometric parameters on the distribution of solar radiation.

Energy Technology Data Exchange (ETDEWEB)

This book comprises an up-to-date description of the astrophysical characteristics of the sun, including modern techniques used in solar research. Provides an historical background of solar research and techniques and covers the necessary astrophysics for solar studies, energy generation in the interior, the convection zone, the non- thermally heated layers, and solar wind are described in detail. Also considers the sun in relation to other stars, including information on its variable outputs of light, charged particles, and fields.

Energy Technology Data Exchange (ETDEWEB)

Intensities of {gamma}-transitions emerging from the EC decay of {sup 203}Pb were measured precisely. The obtained relative {gamma}-intensities are 100%(279.2keV), 4.14+-0.08%(401.3keV) and 0.932+-0.022%(680.5keV). The 279.2 and 680.5keV level feeding {beta}-branching ratios were deduced to be 95.3+-0.1 and 4.7+-0.1% respectively. {sup 203}Pb is suggested for calibration purposes. (author).

Science.gov (United States)

The PVSCAN is an instrument designed to characterize silicon solar cell materials and devices. It performs a host of measurements that yield spatial maps of dislocation density, grain distribution, reflectance, and photoresponses from near-junction and the bulk of a solar cell.

CERN Document Server

We investigate the solar neutrino problem in the scenario of three generation neutrino oscillation hypothesis, taking into account other phenomenological constraints to the neutrino mixing and mass parameters.

Science.gov (United States)

Ti-Ag and Ti-Pd-Ag solar cell contacts structure and degradation dependence on high temperature and humidity environmental exposure

Energy Technology Data Exchange (ETDEWEB)

A module is described with a receiver having a solar energy acceptance opening and supported by a mounting ring along the optic axis of a parabolic mirror in coaxial alignment for receiving solar energy from the mirror, and a solar flux modulator plate for varying the quantity of solar energy flux received by the acceptance opening of the module. The modulator plate is characterized by an annular, plate-like body, the internal diameter of which is equal to or slightly greater than the diameter of the solar energy acceptance opening of the receiver. Slave cylinders are connected to the modulator plate for supporting the plate for axial displacement along the axis of the mirror thereby shading the opening with respect to solar energy flux reflected from the surface of the mirror to the solar energy acceptance opening.

Science.gov (United States)

Jun 10, 2011 ... The PSSC is a picosatellite designed to test the space environment by providing a testbed to gather data on new solar cell technologies.

Science.gov (United States)

High-Temperature Solar Cell Development. Geoffrey A. Landis,. NASA John Glenn Research Center. 21000 Brookpark Road, Cleveland, OH 44135. Danielle ...

Science.gov (United States)

Metal-semiconductor solar cells reported to date exhibit inherently low output voltages. This effect isa consequence of high diode "saturation" ...

Science.gov (United States)

replacing the KDP crystal, and introducing computer programs for accumulation of an almost unlimited number of frames. The calibration procedure using solar ...

CERN Document Server

A new predictive framework for supersymmetry at the TeV scale is presented. The \\mu parameter of the MSSM is replaced by (\\lambda S), where S is a singlet field, and the axion becomes a heavy pseudoscalar, G, by adding a mass, m_G, by hand. The explicit breaking of Peccei--Quinn (PQ) symmetry is assumed to be sufficiently weak at the TeV scale that the only observable consequence is the mass m_G. Three models for the explicit PQ breaking are given; but the utility of this framework is that the predictions for all physics at the electroweak scale are independent of the particular model for PQ breaking. The MSSM parameters \\mu, B are replaced by \\lambda, A_\\lambda. Taking the scalar mass m_S^2 to be sufficiently small and \\lambda = A_\\lambda \\sin (2 \\beta) /2. Our framework leads to a theory similar to the MSSM, except that \\mu is predicted and there are light, weakly-coupled states that lie dominantly in the superfield S. The production and cascade decay ...

International Nuclear Information System (INIS)

The properties of the triplet of low-lying states in "1"0"1Mo have been studied through spectroscopy of the #gamma# radation following thermal neutron capture in "1"0"0Mo and #beta#-decay of "1"0"1Nb and through a measurement of the proton angular distributions in the "1"0"0Mo(d, p) reaction with 14 MeV deuteron energy. The half-lives of the 13.5 keV state and the 57.0 keV 5/2"+ state have been measured as 226(7) and 133(7) ns, respectively. These values and the quadrupole/dipole mixing ratios of the 13.5 keV and 43.5 keV transitions yield spin and parity 3/2"+ for the 13.5 keV level. The E2 components in the 13.5 (3/2"+#->#1/2"+) and 43.5 keV (5/2"+#->#3/2"+) transitions are #<=# 8x10"-"4 and 54(9)%, respectively. The possibility of an additional state near to the 57.0 keV level is discussed. IBFM/PTQM calculations, taking into ...

Energy Technology Data Exchange (ETDEWEB)

In Canada, the cost of heating is a major expense in the operation of greenhouses in the winter season, inhibiting greenhouse production in winter months in most part of the country. Alternative energy sources, such as solar energy and biomass energy may offer an economically feasible heating alternative. A solar energy greenhouse technology developed in northern China for winter vegetable production has demonstrated good potential for Manitoba winter conditions. The design and performance of solar energy greenhouses depend on the geographical location. Therefore, in order to optimize the design of solar greenhouses with respect to the latitude of the location for maximum solar radiation gain, a theoretical analysis was performed that analyzed parameters such as greenhouse length and the roof slope. This paper described the methodology of the study, including a description of ...

Energy Technology Data Exchange (ETDEWEB)

One of the main disadvantages of solar air collectors in practical applications is their relatively low efficiency. In this experimental investigation, the shape and arrangement of absorber surfaces of the collectors were reorganized to provide better heat transfer surfaces suitable for the passive heat transfer augmentation techniques. The performance of such solar air collectors with staggered absorber sheets was tested. The experimental results show that it is possible to provide 10 to 25% enhancement in the efficiency compared to the conventional solar air collectors. (authors)

Science.gov (United States)

No Abstract Available

Energy Technology Data Exchange (ETDEWEB)

The staff of the Southwest Technology Development Institute (SWTDI), in conjunction with the staff of Industrial Solar Technology (IST), have analyzed the performance, operation, and maintenance of a large solar process heat system in use at the 5,000 inmate California Correctional Institution (CCI) in Tehachapi, CA. This report summarizes the key design features of the solar plant, its construction and maintenance histories through the end of 1991, and the performance data collected at the plant by a dedicated on-site data acquisition system (DAS).

Energy Technology Data Exchange (ETDEWEB)

This report contains a set of nomographs which can be used to estimate the average annual solar fraction for solar space and water heating at a large number of DOD facilities. The solar fraction estimated from the nomograph is in close agreement with F-Chart 3.0 and allows for variation of the following parameters: annual load, collector area, collector transmittance-absorptance coefficient, and collector overall loss coefficient.

Energy Technology Data Exchange (ETDEWEB)

A set of nomographs is provided which can be used to estimate the average annual solar fraction for solar space and water heating at a large number of DOD facilities. The solar fraction estimated from the nomograph is in close agreement with F-Chart 3.0 and allows for variation of the following parameters: annual load, collector area, collector transmittance-absorption coefficient, and collector overall loss coefficient.

Science.gov (United States)

Not Available

Energy Technology Data Exchange (ETDEWEB)

The intention of the research carried out was to develop photovoltaic driven solar heating systems applied for drying of medicinal plants in remote areas. Identification of hybrid photovoltaic - photothermal systems was done and discussion of technical features and applicability of such systems in agriculture is presented. Detail technical specification of PV powered medicinal plants solar dryer and cost effectiveness parameters are given. Operational and economic results obtained during testing of the dryer are promising. (orig.) 4 refs.

International Nuclear Information System (INIS)

Three classes of solar emanations, namely, photon radiation from solar flares, solar energetic particles, and inhomogeneities in the solar wind that drive magnetic storms, are examined, and their effects on humans and technological systems are discussed. Solar flares may disrupt radio communications in the HF and VLF ranges. Energetic particles pose a special hazard at low-earth orbit and above, where they can penetrate barriers such as spacesuits and aluminum and destroy cells and solid state electronics. Energetic solar particles also influence terrestrial radio waves propagating through polar regions. Magnetic storms may disturb the operation of navigation instruments, power lines and pipelines, and satellites; they give rise to ionospheric storms which affect radio communication at all latitudes. There is also a growing body of evidence that changes in the ...

Energy Technology Data Exchange (ETDEWEB)

A solar thermal powered aircraft powered by heat energy from the sun. A Rankine-Brayton hybrid cycle heat engine is carried by the aircraft body for producing power for a propulsion mechanism, such as a propeller or other mechanism for enabling sustained free flight. The Rankine-Brayton engine has a thermal battery, preferably containing a lithium-hydride and lithium mixture, operably connected to it so that heat is supplied from the thermal battery to a working fluid. A solar concentrator, such as reflective parabolic trough, is movably connected to an optically transparent section of the aircraft body for receiving and concentrating solar energy from within the aircraft. Concentrated solar energy is collected by a heat collection and transport conduit, and heat transported to the thermal battery. A solar tracker includes a heliostat for determining optimal alignment with the sun, ...

CERN Document Server

Several observational studies suggest that solar wind dynamic pressure fluctuations can drive magnetospheric ultra-low frequency (ULF) waves on the dayside. To investigate this causal relationship, we present results from Lyon-Fedder-Mobarry (LFM) global, three-dimensional magnetohydrodynamic (MHD) simulations of the solar wind-magnetosphere interaction. These simulations are driven with synthetic solar wind input conditions, where idealized ULF dynamic pressure fluctuations are embedded in the upstream solar wind. In three of the simulations, a monochromatic, sinusoidal ULF oscillation is introduced into the solar wind dynamic pressure time series. In the fourth simulation, a continuum of ULF fluctuations over the 0-50 mHz frequency band is introduced into the solar wind dynamic pressure time series. In this numerical experiment, the idealized ...

Energy Technology Data Exchange (ETDEWEB)

Three agricultural applications in a specially designed greenhouse solar system functioning as a multi-purpose solar air collector for crop production and curing/drying processes are examined. An automated hydroponic crop production system is proposed for the greenhouse solar system. Design criteria of the proposed system and its utilization of solar energy for root-zone warming are presented and discussed. Based upon limited testing of the hydroponic system considered, hydroponic production of greenhouse crops is believed reasonable to complement the year-round use of the greenhouse solar system. The hardware/software design features of a microcomputer-based control system applied in the greenhouse solar barn are presented and discussed. On-line management and utilization of incident solar energy by the microcomputer system are investigated ...

Energy Technology Data Exchange (ETDEWEB)

The Active Magnetospheric Particle Tracer Explorers (AMPTE) program provided important information on the behavior of clouds of plasma artificially injected into the solar wind and the earth's magnetosphere. Now that the releases are over, data from the satellites are being analyzed to investigate the processes by which the ambient solar wind mass, momentum, and energy are transferred to the magnetosphere. Work in progress at APL indicates that the solar wind is much more inhomogeneous than previously believed, that the solar wind constantly buffets the magnetosphere, and that ground observers may remotely sense these interactions as geomagnetic pulsations. 8 refs.

Energy Technology Data Exchange (ETDEWEB)

The invention concerns a solar power station with a hollow solar heater, which has reflected radiation coming in, focussed by a mirror through the inlet opening. To match the differing solar radiation during the day, the inlet opening can be adjusted by changing its cross-section. This is done by at least two thick flat circular parts which can move relative to each other which are preferably movable relative to each other in pairs on a common rail and which are cooled by a coolant which is the working medium for absorbing solar energy.

Energy Technology Data Exchange (ETDEWEB)

As concern regarding global environmental problems such as the greenhouse effect and acid rain has increased, so too has the demand for commercially viable solar cells as a clean energy source. Interest in amorphous silicon (a-Si) solar cells has been particularly high, due to their low cost. Technological developments in the field of a-Si solar cells are discussed from the viewpoints of fabrication process, materials, and cell structures. Various applications and systems that take advantage of the a-Si solar cell are then introduced. Finally, future prospects are mentioned

Science.gov (United States)

An electric power generating apparatus is described, including: a solar collector; a primary thermal loop including primary thermal fluid; a cavity receiver to receive reflected solar energy from the solar reflector, convert the solar energy into thermal energy, and transmit the thermal energy to the primary thermal fluid by heating the primary thermal fluid not to exceed a given temperature, the given temperature being substantially equal to 700 F; a Stirling engine receiving the primary thermal fluid heated by the cavity receiver, including means to generate mechanical power and means to generate electrical power from the means to generate mechanical power.

Science.gov (United States)

The differential cross section measurements for /sup 241/Am, /sup 242m/Am and /sup 243/Am are reviewed in the energy range from 0.5 eV to 10 keV. Parameters extracted from resonance analysis, such as the neutron strength function, the average level spacing, the average capture and fission widths, are compared for the various measurements. The average capture and fission cross sections from 100 eV to 10 keV are directly compared. The status of the data set is discussed with suggestions for further measurements. 24 references.

Science.gov (United States)

... In a HEAO 1 study of active galaxies, principally Seyfert 1s, in the 2, 165 keV energy range, Rothschild et al. ... As discussed by Rothschild et al. ...

International Nuclear Information System (INIS)

... gamma cascades kev range 10-100 lifetime lutetium 171 lutetium 173 lutetium

Energy Technology Data Exchange (ETDEWEB)

A solar-powered adsorption air-conditioning system was designed and installed in the green building of Shanghai Research Institute of Building Science. The system contained 150 m{sup 2} solar collectors and two adsorption chillers with nominal refrigeration capacity of 8.5 kW. Based on performance characteristics of the adsorption chiller, the operation mode of the solar-powered air-conditioning system was optimized by maintaining a phase shift of 540 s between the two adsorption chillers. Thereafter, the whole system realized stable operation by the balance of heat consumption and refrigeration output. From June to August of 2005, the solar-powered air-conditioning system continuously ran between 9:00 and 17:00. The operation performance of the system under representative working condition showed that the average refrigeration output of the solar-powered air-conditioning system was ...

Energy Technology Data Exchange (ETDEWEB)

This research report for the Swiss Federal Office of Energy (SFOE) presents the results of a project that examined the feasibility of setting up 'MINERGIE' low-energy-consumption module standards for the production of heat in small residential buildings. The aims of the standards and the basic idea behind the MINERGIE-modules are discussed. The concepts of the modules for heat pumps and wood-fired heating systems and their combination with solar installations are examined, as are their areas of application. The requirements placed on the modules are listed. System concepts, including simple schematics for typical installations, are presented for wood-log, wood-chippings and pellets-fired systems as well as for ground-loop and air-water heat pump systems as well as their solar-aided counterparts. The results of cost-benefit analyses are presented and questions regarding system guarantee and liability are examined.

British Library Electronic Table of Contents (United Kingdom)

This study addresses the solar thermal decomposition of natural gas for the co-production of hydrogen, as well as Carbon Black as a high-value nano-material, with the bonus of zero CO2 emissions. The work focused on the development of a medium-scale solar reactor (10kW) based on the concept of indirect heating. The solar reactor is composed of a cubic cavity receiver (20cm side), which absorbs concentrated solar irradiation through a quartz window via a 9cm-diameter aperture. The reacting gas flows inside four graphite tubular reaction zones that are settled vertically inside the cavity. Experimental results were as follows: methane conversion and hydrogen yield of up to 98% and 90%, respectively, were achieved at 1770K, and acetylene was the most important by-product, with a mole fraction...

Energy Technology Data Exchange (ETDEWEB)

A discussion is presented of the 750-KeV chopper experience with both proton and negative ion beams and the ability of these systems to tailor the Linac beam to the diverse requirements of its users; normal accelerator injection, neutron therapy beam, and electron cooling experiments. This flexibility plus a cleaner beam pulse, improved thyratron operation, and mechanical modularity are the results of recent improvements. Additional benefits have been increased reliability and ease of service to the 750-KeV chopper. 3 refs.

International Nuclear Information System (INIS)

A radiometric method was elaborated for surface density determinations of the adhesive layer of plasters by radionuclide X-ray fluorescence using the 17.47 keV bremsstrahlung of "1"4"7Pm/Mo. The bremsstrahlung line excites the 8.63 keV characteristic K#alpha# line of Zn contained in the adhesive layer of the plaster as a filling material in the form of ZnO. In homogeneous adhesive layers the Zn content is proportional to surface density. (author).

Energy Technology Data Exchange (ETDEWEB)

A technique has been developed for high resolution alpha particle spectroscopy from track length determination in CR-39 plastic. On individual tracks an energy resolution deltaE close to the range straggling limit is obtainable. For 6 MeV alpha-particle deltaE is proportional 35 keV on individual particles and for groups of particles deltaE proportional 20 keV can be achieved using certain data selection criteria. At 100 keV on individual particles deltaE is proportional 20 keV. The analysis requires 1) a knowledge of the track-etch rate (Vsub(T))-range relationship and 2) a theoretical understanding of alpha-particle track structure in CR-39 as a function of particle energy, dip angle and degree of etching. The structure of alpha-particle etched tracks in CR-39 is described and two methods of analysis discussed. Examples are given of the resolution attainable on tracks of alpha-particles as natural ...

International Nuclear Information System (INIS)

Low-energy focused ion beam (FIB) is a useful tool for shallow doping, gas-assisted etching, and other uses to minimize substrate damage in semiconductor device fabrication. The possibility to form a finely FIB of low energy under 1 keV was suggested in the investigations on the retarding mode in electron optical systems. The abilities of the simplest type of retarding mode FIB column are examined here. The optical properties are calculated for the corresponding model and some images are observed with Ga"+ ion beams <0.3 #mu#m in diameter for beam energies, 10, 5, and 1 keV, using a retarding mode one-lens FIB system. 1-keV and 100-eV Ga"+ FIB was implanted to Ga/As substrate, and the defects are analyzed by deep-level transient spectroscopy. The defect concentration for 100 eV was < (1)/(5) that for 1000 keV.

Energy Technology Data Exchange (ETDEWEB)

The dwelling is equipped with solar collectors which heat the air circulating in the cavity walls and the space beneath the floors. The thermal aspects of such a building are described. Heat balance, losses, heating by the sun in different seasons are described. Different measures taken to reduce the energy losses are described.

Energy Technology Data Exchange (ETDEWEB)

Forms used in conducting a national survey about solar energy are presented. Forms for representatives from the domestic, commercial, and industrial sectors, owners and non-owners of solar equipment, are shown. Participants were to be contacted by telephone, mail, and personal visits. (MCW)

Energy Technology Data Exchange (ETDEWEB)

Performance and operating characteristics are presented for a solar powered aircraft intended to remain aloft for long periods. The critical technologies which limit the performance are identified. By using the techniques presented, the effects of variation in the system parameters are studied. Practical design consideration are discussed.

Energy Technology Data Exchange (ETDEWEB)

A brief overview of the conceptual design of a solar central receiver system integrated with an existing cogeneration facility is provided. A synopsis of the performance and economic evaluation, and an assessment of the concept from the site owner's perspective are given.

Energy Technology Data Exchange (ETDEWEB)

Conference paper regarding research in freeze-protection methods that could extend market acceptance for passive solar domestic water heating systems in more northern climates if the U.S.

Energy Technology Data Exchange (ETDEWEB)

Topics covered include various aspects of solar cell fabrication and performance. Aluminium-gallium arsenides, cadmium telluride, amorphous silicon, and copper-indium-gallium selenides are all characterized in their applicability in solar cells.

Energy Technology Data Exchange (ETDEWEB)

Laser assisted solar cell metallization processing which is a one step process is examined. The potential advantages of laser disposition techniques for photovoltaic systems are: a high resolution, no photolithography, clean and contamination free, in-situ sintering, and low contact resistance.

Science.gov (United States)

The applicability of isothermal solidification as a contacting method for solar cells was proved for the systems AgSn and AuIn. The process is advantageous in that it requires no fluxes, no inert gases, and no pretreatment of the components. The IE contac...

Science.gov (United States)

Metal-Semiconductor Solar Cells," J. Appl. Phys. 46,. 1286 (1975). 12) H. B. Kim , G. G. Sweeney and I. S. Heng, "Analysis of ...

Energy Technology Data Exchange (ETDEWEB)

The purpose of this solar energy project was to design, manufacture, install, maintain and evaluate solar heating systems in order to stimulate community acceptance of the practicality of solar applications, reduce non-renewable energy resource consumption, and decrease residential expenditures for energy. The project also provided skill training and experience for CETA employees in the design, manufacture, and installation of solar energy equipment systems. CDC's contract had four separate solar energy projects; namely: Domestic Water Heating Systems for four Single-Family Homes; Domestic Water Heating for an industrial building; Domestic Water Heating for a (4) unit apartment complex (includes (12) supplemental space heating units); and Integral Passive Water Heaters and Energy Conservation Devices for (8) one bedroom homes. CDC staff designed all ...

Energy Technology Data Exchange (ETDEWEB)

In this report, the main emphasis is given to (1) the problems associated with the basic calibration of the spectroradiometer and (2) the year-to-year variability of the calibrations of the solar UV network radiometers. Also, the results from intercomparisons of the Brewer and OL 742 spectroradiometers are included

Science.gov (United States)

ADVANCED MODELING, S IMULATION, AND ANALYSIS (ROADMAP 14). ...... Metal/Silicon Extraction from Regolith & manufacturing ..... addresses solar power, energy storage (in conjunction with solar power and as a prime source of ...

Energy Technology Data Exchange (ETDEWEB)

A conceptual design of a solar retrofit to US Gypsum's plant at Sweetwater, Texas, has been developed which provides heated air to a large gypsum board drying kiln that is currently under construction. The solar heated air displaces natural gas normally used for the process heat. The solar retrofit is composed of a tower focus collector with a cavity receiver which uses air as the heat transfer fluid. An executive summary of the conceptual design, system performance, economics, and development plan is presented. (WHK)

Energy Technology Data Exchange (ETDEWEB)

Solar heating of gas turbine plants is moving back to the focus of current research. The mainly unsteady operation of solar turbine power plants can only be predicted with sufficient accuracy if the transient behavior of the solar radiation receiver is known. Therefore the transient behavior of cavity receivers of different designs is investigated. The mathematical model used to simulate heat transfer and energy storage is illustrated. Computed results for two receivers with different inner lining are compared and evaluated concerning their use in practice.

Energy Technology Data Exchange (ETDEWEB)

A solar energy receiver is described including a separable endless wall formed of a ceramic material having defined therein a cavity of a substantially cylindrical configuration for entrapping solar flux, and an acceptance aperture adapted to admit to the cavity a concentrated beam of solar energy, said wall being characterized by at least a pair of contiguously related segments separated by lines of cleavage intercepting said aperture, at least one of the segments being supported for pivotal displacement, and a thermal responsive actuator adapted to respond to excessive temperatures within the cavity for initiating pivotal displacement of said one segment, whereby thermal flux is permitted to escape from the cavity.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

British Library Electronic Table of Contents (United Kingdom)

The Monte Carlo ray-tracing method is applied and coupled with optical properties to predict the radiation performance of solar concentrator/cavity receiver systems. Several different cavity geometries are compared on the radiation performance. A flux density distribution measurement system for dish parabolic concentrators is developed. The contours of the flux distribution for target placements at different distances from the dish vertex of a solar concentrator are taken by using an indirect method with a Lambert and a charge coupled device (CCD) camera. Further, the measured flux distributions are compared with a Monte Carlo-predicted distribution. The results can be a valuable reference for the design and assemblage of the solar collector system.

Science.gov (United States)

MILSTAR's Flexible Substrate Solar Array (FSSA) is an evolutionary development of the lightweight, flexible substrate design pioneered at Lockheed during the seventies. Many of the features of the design are related to the Solar Array Flight Experiment (SAFE), flown on STS-41D in 1984. FSSA development has created a substantial technology base for future flexible substrate solar arrays such as the array for the Space Station Freedom. Lessons learned during the development of the FSSA can and should be applied to the Freedom array and other future flexible substrate designs.

Energy Technology Data Exchange (ETDEWEB)

Laser-assisted processing techniques for producing high-quality solar cell metallization patterns are investigated, developed, and characterized. The tasks comprising these investigations are outlined. A new batch of solar cells was processed using the laser decomposition of spun-on silver neodecanoate to metallize cells. Decomposition of silver neodecanoate was carried out at different laser powers on different cells on a given wafer to determine whether this would have any effect on cell performance. Solar cells which were written with laser powers of 5 to 8 watts, gave excellent results with cell efficiencies in the range of 14 to 16%.

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

Energy Technology Data Exchange (ETDEWEB)

The performance of a solar chemical heat pipe was studied using CO{sub 2}reforming of methane as the endothermic reaction. A directly heated vertical reactor, packed with a rhodium catalyst was used. The solar tests were carried out in the Schaeffer solar furnace of the Weizmann Institute of Science. The power absorbed was up to 6.3 KW, the maximal flow rates of the gases reached 11,000 1/h, and the methane conversions reached 85%. A computer model was developed to simulate the process. Agreement of the calculations with the experimental results was quite satisfactory.

Energy Technology Data Exchange (ETDEWEB)

This proceedings volume contains contributions by about 70 authors on market trends, funding, marketing, boundary conditions and sales promotion of thermal solar energy and photovoltaic systems. The contributions reflect the diversity of authors, e.g. consultants, advocates and agents of solar technology producers and financial organisations. Central issues were markets in and outside Europe, quality assurance, interdepartmental cooperations, and marketing strategies of the solar industry. The proceedings volume also contains the conference schedule and self-descriptions of the authors' institutions. (orig.)

Energy Technology Data Exchange (ETDEWEB)

This publication of the Areva Group, a world nuclear industry leader, provides information on the energy in many domains. This issue deals with the nuclear fuel cycle, the biofuels, the everyday geothermal power, the Unites States energy supply and types, the Bertrand Picard solar aircraft, the kyoto protocol and the wind power leaders. A special chapter is devoted to the renaissance of solar homes. (A.L.B.)

Energy Technology Data Exchange (ETDEWEB)

In December 1980, Guenther Rochelt from Munich (FRG) managed the first flight in a solar aircraft. Energy was supplied by 2,500 solar cells with a rated power of 2.2 kW. Self-starting and flying were made possible by a special aircraft construction with an electromotor with a gross power of 1.8 and a rated voltage of 88 V.

Energy Technology Data Exchange (ETDEWEB)

This volume on specifications for the Saguaro Power Plant includes the following: subsystem interface definition document; solar collector subsystem specification; receiver specification; thermal energy storage specification; solar steam generator specification; and master control system specification.

Energy Technology Data Exchange (ETDEWEB)

Performance predictions have been made for attached-sunspace types of passively solar heated buildings. The predictions are based on hour-by-hour computer simulations using computer models developed in the framework of PASOLE, the Los Alamos Scientific Laboratory (LASL) passive solar energy simulation program. The models have been validated by detailed comparison with actual hourly temperature measurements taken in attached-sunspace test rooms at LASL.

Energy Technology Data Exchange (ETDEWEB)

The concept of a multi-cavity volumetric solar receiver is very attractive for the profitability of certain of its characteristics such as high efficiency and economy. The absorber is based on a pack of small ceramic cavities which intercept and absorb the inherent high solar flux reflected from an array of mirrors. Atmospheric air acts as a coolant medium when it is drawn through the pack. A model for an overall heat transfer performance of the receiver is given and numerically solved.

Energy Technology Data Exchange (ETDEWEB)

Solar cookers offer a viable alternative to conventional cooking methods in many areas, and can be an effective tool in the fight against the deforestation and desertification that plague many developing countries. However, there have been numerous obstacles to the successful dissemination of solar cookers in the past. The purpose of this paper is to identify opportunities, review constraints and develop a marketing strategy to disseminate the Sundyne Solar Cooker (SSC) in developing countries.

Energy Technology Data Exchange (ETDEWEB)

The Department of Energy's National Solar Data Program established solar energy systems in residential and commercial buildings across the United States. These solar sites are linked to Vitro Laboratories Division's computer in the National Solar Data Network (NSDN). Vitro collects and analyzes data from this network to determine the thermal performance of each of the solar systems. The network consists of: (1) sensors which measure key performance parameters at a selected site; (2) a Site Data Acquisition Subsystem (SDAS); (3) telephone transmission circuits; and (4) a Central Data Processing System (CDPS). For the majority of parameters, raw data is collected approximately every five minutes. Solar insolation and certain other parameters, which are subject to rapid variance, are sampled every 32 seconds. Environmental information collected at ...

Energy Technology Data Exchange (ETDEWEB)

The mainly nonstationary operation of a solar-heated receiver can be simulated with sufficient accuracy only if data about the dynamic behavior are available. For this reason, the dynamic behavior of a solar cavity receiver with parabolic dish collector is investigated. The development of a mathematical simulation considering heat transfer and storage processes is presented and the procedure for a numerical solution is illustrated. The performance of the calculation method is finally demonstrated by simulating the passage of a cloud.

Energy Technology Data Exchange (ETDEWEB)

A new highly concentrating solar research furnace has recently been completed at the University of Minnesota. The experimentally observed flux concentration ratio, at small aperture, of a cavity receiver is about 7000. The furnace embodies features which may be of interest to others in the solar energy community. This paper describes its construction and performance.

International Nuclear Information System (INIS)

We have shown that energy contamination introduced by ion beam deceleration technology that is used to increase the beam currents available for low energy boron implants, can affect fabricated junctions adversely. A 4 keV "1"1B beam is extracted and retarded by a potential of -3.5 keV for 0.5 keV "1"1B implantation, or by a potential of -3.8 keV for 0.2 keV "1"1B implantation. Intentional beam contamination was introduced by turning off the retarding potential to allow the 4 keV "1"1B ions to irradiate Si wafers directly. The percentage of contamination, at levels of 0.1%, 0.2% and 0.3% was introduced. Rapid thermal annealing of all the implanted samples was performed under N_2 ambient at 1050 deg. C for 1 s. The dopant tail profiles themselves are not significant if the contamination levels are low. However, the much higher damage level coming from high energy ...

British Library Electronic Table of Contents (United Kingdom)

Solar cavity receiver plays a dominant role in the light-heat conversion. Its performance can directly affect the efficiency of the whole power generation system. A combined calculation method for evaluating the thermal performance of the solar cavity receiver is raised in this paper. This method couples the Monte-Carlo method, the correlations of the flow boiling heat transfer, and the calculation of air flow field. And this method can ultimately figure out the surface heat flux inside the cavity, the wall temperature of the boiling tubes, and the heat loss of the solar receiver with an iterative solution. With this method, the thermal performance of a solar cavity receiver, a saturated steam receiver, is simulated under different wind environments. The highest wall temperature of the boi...

British Library Electronic Table of Contents (United Kingdom)

In the last years, the growing demand for air conditioning has caused a significant increase in demand for primary energy resources. Solar-powered cooling is one of the technologies which allows to obtain, by using the renewable solar source, an important energy saving compared to traditional air conditioning plants. The paper describes different technical installations for solar cooling, their way of operation, advantages and limits. The objective of the present study has been to analyze the technical and economic feasibility of solar absorption cooling systems, designed for two different application fields: industrial refrigeration and air conditioning. The possibility to replace or integrate the existing plants is studied, by considering the refrigeration requirements of a company, whic...

Energy Technology Data Exchange (ETDEWEB)

For a solar cell, in order to minimize the loss of incident light, transparent glass or plastic material is used at the incident part. When a solar cell is watched from the light incident part, a silicon base material is directly observed with either block or brown color only. This invention enables a solar cell to give brighter color on the incident surface by placing a reflective film which reflects only the light of specific wavelength, without reducing the efficiency of the solar cell. This reflective film consists of multi-layered dielectric with 12 layers and alternative combination of highly refractive and less refractive substances. Highly refractive layer is Y/sub 2/O/sub 3/ with refractive index 1.74 and the less refractive layer is SiO/sub 2/ with refractive index 1.45. (5 figs)

Energy Technology Data Exchange (ETDEWEB)

This is a process for manufacturing a semi-rigid, folding solar generator manufactured from several coated solar cells (Cics), which has at least two folding parts connected together so as to turn by hinges, characterized by the following stages of the process: a) On the back of matrix subsections, in order to cover the connector, carbon fibre strips are glued on, which project over the upper or lower edge of each matrix subsection. b) The projecting ends of adjacent carbon fiber strips are connected with two carbon fibre strips. c) At least two matrix subsections are fixed in separately manufactured carbon fiber frames, and d) the carbon fiber frames, together with the matrix subsections are connected via hinges to a solar generator.

Science.gov (United States)

A glass heat pipe is adapted for use as a solar energy absorber in an evacuated tube solar collector and for transferring the absorbed solar energy to a working fluid medium or heat sink for storage or practical use. A capillary wick is formed of granular glass particles fused together by heat on the inside surface of the heat pipe with a water glass binder solution to enhance capillary drive distribution of the thermal transfer fluid in the heat pipe throughout the entire inside surface of the evaporator portion of the heat pipe. Selective coatings are used on the heat pipe surface to maximize solar absorption and minimize energy radiation, and the glass wick can alternatively be fabricated with granular particles of black glass or obsidian.

British Library Electronic Table of Contents (United Kingdom)

An exergy analysis method is presented of the solar multi-effect humidification?dehumidification desalination (HDD) process. Pinch technology is used in the humidification process to determine the maximum possible saturated air temperature and the temperature of water rejected from the unit, and then the dehumidification process to determine the temperature of water leaving from the heat exchanger. The formulae to calculate the exergy of water and saturated air are given. The solar plane collector is used. From exergy analysis, the solar collector has the lowest exergy efficiency; the HDD process has a lower exergy efficiency, and the water rejected has also a large exergy loss. The energy and exergy recovery rate of the desalination process is also lower. The solar multi-effect HDD proces...

Energy Technology Data Exchange (ETDEWEB)

A review of the deep-level defects observed in both electron- and proton-irradiated GaAs solar cells is presented. Studies of the effects of periodic and continuous thermal annealing on the radiation-induced electron and hole traps and the recombination parameters in GaAs solar cells were made for a wide range of electron and proton energies, fluence, annealing temperature and annealing time. A refined model for numerical simulations of the displacement damage was developed for computing the defect density and the cell parameters in the electron- and proton-irradiated GaAs solar cells. Excellent agreement was obtained between the calculated values and the experimental data for the proton-irradiated GaAs solar cells. (orig.).

Energy Technology Data Exchange (ETDEWEB)

The field of micro unmanned aerial vehicles ({mu}UAVs) has advanced rapidly in recent years. This paper studies the design and construction of a small solar-powered aircraft near the size range of current {theta}UAVs. A number of aspects of their design were analysed, including structural, aerodynamic and propulsion system considerations. The effect of small-scale, low Reynolds number aerodynamics was investigated, and the performance of a range of candidate aerofoils was compared. The integration of a solar power source into the aircraft system was considered a key design issue. Consequently, a number of aircraft configurations were examined, with the intention of optimising the application of solar power in a miniature aircraft. Investigation of improved system components suggests that a practical solar-powered aircraft in the size range below 500 mm maximum linear dimension should be viable given ...

British Library Electronic Table of Contents (United Kingdom)

This paper presents a hybrid solar desalination process of the multi-effect humidification dehumidification and the basin-type unit. The sketch of the hybrid solar desalination process is given. The solar vacuated tube collector is employed in the desalination system, multi-effect humidification dehumidification desalination (HDD) process is plotted according to pinch technology, and then the water rejected from multi-effect HDD process is reused to desalinate in a basin-type unit further. The gain output ratio (GOR) of this system will rise by 2?3 at least through reusing the rejected water. The research proves that the multi-effect HDD has much room to be improved. A hybrid solar desalination process of the multi-effect humidification dehumidification and the basin-type unit should be no...

Science.gov (United States)

The decays of Ta/sup 177/ and Lu/sup 177/ to levels in vestigated with beta spectrometers, NaI(Tl) gamma spectrometers, and fast coincidence and angular correlation techniques. Energy levels in Hf/sup 177/ were characterized according to their energy (kev), the Nilsson asymptotic quantum numbers (Nn/sub 2/ LAMBDA ), the total angular momentum and its component along the symmetry axis (I,K), and the parity ( pi ) as follows: 0STA5I4 7/2, 7/2-!; 112.97STA514 9/2, 7/ 2-!; 249.7STA5I4 11/2, 7/1-!; 32l.34STA624 9/2, 9/2+1; 447.9STA624 11/2, 585.8STA642 7/2, 3/2+1; 509.0STA5I2 5/2, 5/1-1; 605.5STA512 7/2, 5/2-!; 746.04STA633 7/2, 7/2+1; 848.2STA 633 9/2, 7/2+1; and 1058.38STA503 7/2, 7/2-!. The levels at 447.9, 488.8, and 585.8 kev are tentative. The spins and parities were uniquely determined by angular correlation and internal conversion data for the levels at 746.0 and 848.2 kev, asof the levels at 0, ...

Energy Technology Data Exchange (ETDEWEB)

At COP3 in 1997, an agreement was made to the innovative technical development/promotion by international cooperation, and the promotion of transfer of environmental technology to developing countries. Under the agreement, a feasibility study of international cooperation was made, and especially a study was conducted of the utilization/development of solar energy by the innovative solar thermochemical process. The main reason for global warming is emissions of a large amount of CO2 caused by the direct combustion of fossil fuels. Therefore, a CO2 recycle system taken up in the study enables a more substantial decline in CO2 emission (kg/kWh) per unit generation than the conventional thermal power system by composing solar methanol or solar dimethyl ether using fossil fuels including coal, water, CO2, etc. as raw materials and using solar energy as heat source, and by using this as ...

CERN Document Server

We demonstrate that a massive asymptotic giant branch (AGB) star is a good candidate as the main source of short-lived radionuclides in the early solar system. Recent identification of massive (4-8 solar masses) AGB stars in the Galaxy, which are both lithium- and rubidium-rich, demonstrates that these stars experience proton captures at the base of the convective envelope (hot bottom burning), together with high-neutron density nucleosynthesis with 22Ne as a neutron source in the He shell and efficient dredge-up of the processed material. A model of a 6.5 solar masses star of solar metallicity can simultaneously match the abundances of 26Al, 41Ca, 60Fe, and 107Pd inferred to have been present in the solar nebula by using a dilution factor of 1 part of AGB material per 300 parts of original solar nebula material, and taking into account a time interval between ...

International Nuclear Information System (INIS)

An experimental investigation of a humidification-dehumidification desalination (HDD) process using solar energy at the weather conditions of Suez City, Egypt, is presented. A test rig is designed and constructed to conduct this investigation under different environmental and operating conditions. The test rig consists of a solar water heater (concentrator solar collector type), solar air heater (flat plate solar collector type), humidifier tower and dehumidifier exchanger. Different variables are examined including the feed water flow rate, the air flow rate, the cooling water flow rate in the dehumidifier and the weather conditions. Comparisons between the experimental results and other published results are presented. It is found that the results of the developed mathematical model by the same authors are in good agreement with the experimental results. The tested results show ...

Energy Technology Data Exchange (ETDEWEB)

A numerical investigation of a humidification dehumidification desalination (HDD) process using solar energy is presented. The HDD system consists mainly of a concentrating solar water heating collector, flat plate solar air heating collector, humidifying tower and dehumidifying exchanger. Two separate circulating loops constitute the HDD system, the first for heating the feed water and the second for heating air. A mathematical model is developed, simulating the HDD system, to study the influence of the different system configurations, weather and operating conditions on the system productivity. The model validity is examined by comparing the theoretical and experimental results of the same authors. It is found that the results of the developed mathematical model are in good agreement with the experimental results and other published works. The results show also that the productivity of the unit is strongly influenced by ...

Energy Technology Data Exchange (ETDEWEB)

An updated review of the state of the art in the development of GaAs solar cells is provided, with emphasis on AlGaAs-GaAs cells suitable for space applications. A set of theoretically derived characteristics is given for this type of solar cell. Comparison of measured performance with theory shows excellent agreement. Data on the effects of radiation damage (high-energy electrons, protons, and neutrons) is also integrated into a form useful for evaluation purposes. Techniques for fabricating (AlGa)As-GaAs solar cells in quantities large enough for practical applications are discussed and are shown to have been demonstrated. The possibility of extending these techniques to the fabrication of very thin low-weight cells for space applications is also considered. Finally, the results obtained to date in the development of GaAs solar cells for applications requiring concentrated sunlight are reviewed, for ...

Energy Technology Data Exchange (ETDEWEB)

The environmental data for the NSDN are presented in the form of tables for each solar site. The solar sites are grouped into 12 zones, each of which consists of several adjacent states. The solar energy sites are in alphabetical sequence within each zone. The tables provide available meteorological data for reporting sites in the NSDN as follows: Insolation - the insolation table presents the total, diffuse, direct, maximum, and extra-terrestrial radiation for the solar site. It also shows the ratio of total extra-terrestrial radiation, as a percent. Temperature - the temperature table gives the average, daytime, nightime, maximum, minimum and inlet-water temperatures for the solar site. Additional tables are presented for some of these NSDN sites, supplying either wind or relative humidity data, or both. Wind - all of the passive and some of the active solar ...

International Nuclear Information System (INIS)

Rossi X-ray Timing Explorer (RXTE) observations of the bright supernova remnant Cas A have revealed a hard power law component above 10 keV in addition to two thermal components inferred from ASCA measurements of the many line centroids from low-Z elements. The power law can be shown to be consistent with synchrotron emission from radio to hard x-rays by electrons of up to 4 x 10"1"3 eV. Measurement of the 1157 keV line by CGRO from "4"4Sc in the chain of decay of "4"4Ti predicts that the two "4"4Ti lines at 68 and 78 keV should appear at the CGRO intensity. RXTE has placed upper limits on such lines that are marginally consistent with the CGRO measurement. Implications of these results on sites for cosmic ray acceleration and nucleosynthesis are discussed.

Energy Technology Data Exchange (ETDEWEB)

A 500 keV negative-ion based NBI system is under construction for NB current drive and plasma core heating in high density plasma in JT-60U. Part of the beamline and the high voltage power supply required for a verification test of an ion source was completed in March 1995. After having done a high potential test of the power supply, the negative-ion generation and acceleration tests started in June 1995 aiming at deuterium beams of 500 keV, 22A. In initial experiment, deuterium negative-ion beams of 410 keV, 6.1A (2.5 MW) for 0.2 sec, so far, have been achieved. This is the world highest D{sup {minus}} current and negative ion beam power. The construction of the total system will be completed by the beginning of 1996, and the beam injection will start in March 1996.

Energy Technology Data Exchange (ETDEWEB)

Neutron capture ..gamma..-ray spectra have been measured at 11 average neutron energies from 10 to 530 keV in /sup 88/Sr using a 20 x 15 cm NaI detector with time-of-flight discrimination of background events. The partial radiation widths and the calculated partial valence widths are compared for the strong p-wave resonances at 287 and 321 keV and found to be highly correlated. At these energies, the spectra are dominated by strong transitions to low-lying single particle states, in confirmation of the role of valence capture in the 3p region. However, the data do not support this mechanism at <508> keV.

Science.gov (United States)

as for direct energy conversion in specialized direct electrical energy conversion plants. Figure 1. An energetic (~163KeV) proton and a 11boron nucleus fuse ...

International Nuclear Information System (INIS)

several authors tried to drive codes to construct nuclear level scheme of nuclei using a set of measured gamma -ray transitions and known energy levels, Ritz combination principle proved to be useful in constructing a more complete decay scheme. In this thesis the energy level schemes of some nuclei have been investigated by the measurements of the gamma - ray energies and use of Ritz combination code. The nuclei under investigation are "110m Ag (253 d)"110 Cd and "166m Ho (1200 yr) "166 E r. On the basis of the suggested level at 2249.02 keV by the Ritz code new positions of the two gamma-ray transitions at 677.5 and 706.6 KeV are found in decay scheme of "110m Ag. Also by this code, new position for the 994.84 KeV gamma-ray transition were established to depopulate the level at 1075.2 KeV.

International Nuclear Information System (INIS)

We demonstrate that the excess vacancies induced by a 1 MeV Si implant reduce the excess interstitials generated by a 40 keV Si implant during thermal annealing when these two implants are superimposed in silicon. It is shown that this previously observed reduction is dominated by vacancy annihilation and not by gettering to deeper interstitial-type extended defects. Interstitial supersaturations were measured using B doping superlattices (DSL) grown on a silicon-on-insulator (SOI) substrate. Implanting MeV and keV Si ions into the B DSL/SOI structure eliminated the B transient enhanced diffusion normally associated with the keV implant. The buried SiO_2 layer in the SOI substrate isolates the deep interstitials-type extended defects of the MeV implant, thereby eliminating the possibility that these defects getter the interstitial excess induced by the keV Si implant. copyright 1999 American Institute ...

Energy Technology Data Exchange (ETDEWEB)

The essential mechanical and electronic parts of a beam pulsing system are described, which reaches an energy resolution of ..delta..E/E=0.1%-0.4% in the energy range from 100 eV and 10 keV.

Science.gov (United States)

Nov 14, 2009 ... Ring Current electrons from the Fok Ring Current Model are computed using plasma and magnetic field values from the SWMF magnetosphere ...

Science.gov (United States)

Nov 14, 2009 ... Ring Current electrons from the Fok Ring Current Model are computed using plasma and magnetic field values from the SWMF magnetosphere ...

Energy Technology Data Exchange (ETDEWEB)

A method of Kelvin-day function for climatic solar heating design is presented. The long term temperature distribution is used to find the solar fraction for building heating. A solar heating system is considered to provide heat needed up to an auxiliary heater cut-in temperature which is determined by both heat gain of solar heating system and overall heat loss coefficient of the building. The amount of auxiliary heat needed is calculated from a Kelvin-day value at this cut-in temperature. The cut-in temperature will change from different solar heating system designs, and the Kelvin-day value at this cut-in temperature will be varied. By using the numerical curve-fitting method, the Kelvin-day value at any temperature base can be expressed into a second order algebraic equation, thus, the whole data need not be put into computer storage. It will be very convenient to determine the ...

International Nuclear Information System (INIS)

Total M X-ray cross sections for 12 elements in atomic range 70#<=#Z#<=#92 were measured at 5.96 keV Mn K X-ray photon energy. The average M shell fluorescence yields (anti #omega#_M) of these elements have also been observed using the presently measured cross section values and the theoretical M shell photoionisation cross section values. (orig.).

Energy Technology Data Exchange (ETDEWEB)

The process of inelastic scattering of hot plasma electrons with energies upto 3 keV by a pair of close-lying nuclear levels (..delta../ital E/less than or equal to2keV), one of whichis isomeric, is discussed. The transition cross sections in the nuclei/sup 242/Am, /sup 171/Lu, and /sup 73/Se are calculated. Estimates of the numberof isomeric nuclei de-excited as a result of electron-stimulated processes in aplasma with parameters characteristic of present-day experiments in controlledthermonuclear fusion are given.

Energy Technology Data Exchange (ETDEWEB)

In this work, the chemical transformations induced by 5 keV protons (10{sup 6} ion cm{sup -2}) at the surface of 0.4 {mu}m polyacrylonitrile and polymethacrylonitrile films are analysed by XPS and IRRAS. Spectroscopic changes in both the polymers are globally similar, the most significant feature being a lower relative concentration of nitrogen with respect to carbon closer to the surface. Quantitatively, this change is more marked in the case of polyacrylonitrile which suggests a direct relation with the hydrogen in {alpha} to the nitrile function.

Energy Technology Data Exchange (ETDEWEB)

This paper reports the study results on the standard weather data necessary for simulation of PV power generation systems in fiscal 1994. In the study on the selection criterion of the standard weather data from the viewpoint of PV power generation systems, three typical years are used; a year with average solar radiation, and two years with extremely less and more solar radiation for safe simulation. The standard weather data are arranged for output calculation of PV power generation systems by selecting the most typical year based on long-term observation data. The data to be arranged are as follows; total, direct and scattered solar radiations incident upon a horizontal surface, solar radiation upon a slope surface, sunshine duration, air temperature, wind direction, wind velocity, amount of precipitation, and snow depth. For arrangement of the nationwide standard weather data, estimation of total ...

CERN Document Server

We present the initial results of an observational study into the variation of the dominant length-scale of quiet solar emission: supergranulation. This length-scale reflects the radiative energy in the plasma of the upper solar chromosphere and transition region at the magnetic network boundaries forming as a result of the relentless interaction of magnetic fields and convective motions of the Sun's interior. We demonstrate that a net difference of ~0.5Mm in the supergranular emission length-scale occurs when comparing observations cycle 22/23 and cycle 23/24 minima. This variation in scale is reproduced in the datasets of multiple space- and ground-based instruments and using different diagnostic measures. By means of extension, we consider the variation of the supergranular length-scale over multiple solar minima by analyzing a subset of the Mt Wilson Solar Observatory (MWO) Ca II K image record. The ...

Science.gov (United States)

The system of the early forecast of radiation hazardous fluxes of solar cosmic rays in space on the basis of the real time neutron monitors data obtained by the NMDB (Neutron Monitor Data Base) network is created. The forecast system is based on a short cut technique of definition of a spectrum of solar protons from the data of the limited number of neutron monitor stations and with a simplified procedure of accounts. It is shown that the results of computations of solar proton spectra with the short-cut technique little differ from spectra obtained with a complete technique at energies less than 5 GeV. Thus the good agreement between derived from the neutron monitor data intensities of solar protons in an energy range of hundreds MeV with the data of direct measurements of solar protons at GOES-11 spacecraft is observed. The maximum of increase on neutron monitors outstrips on ...

International Nuclear Information System (INIS)

Else of solar energy as substitute for conventional fuels at a competitive cost requires efficient conversion from solar radiation to usable forms of energy. In solar thermal or thermochemical applications, high efficiency usually re- quires high temperature and high concentration of incoming radiation. The main form of energy loss from high temperature solar central receivers is thermal emission ('re radiation'), at an effective temperature close to the maximum receiver temperature. This loss is reduced if the aperture is divided into segments, most of which are maintained at lower temperatures. A two-stage partitioned receiver demonstrating this concept is under construction at the Weizman Solar Tower. The high-temperature stage is the DIAPR (Directly Irradiated Annular Pressurized Receiver). The low-temperature stage is made of tubular cavity receivers of simpler design. ...

Energy Technology Data Exchange (ETDEWEB)

Apparatus for minimizing thermal loss in a windowless, open cavity solar receiver due to airflow at the receiver aperture includes means for deflecting wind away from the cavity opening such that flow stream reattachment occurs away from the receiver aperture to provide a dead air zone at the cavity opening. This prevents turbulent-mixing airflow exchange between ambient air and heated air within the solar receiver. The wind deflector apparatus includes either a passive annular deflection foil at the receiver aperture, or an active device for producing an outwardly projected air jet at the receiver aperture.

Energy Technology Data Exchange (ETDEWEB)

This book contains the results of an architectural evaluation of building examples with integrated photovoltaic. Danish Building and Urban Research and Danish Technological Institute conducted the work within the framework of Solar Energy Centre Denmark. Seven examples are selected to inspire Danish architects and building owners to use PV in the building environment. The examples come from Denmark and countries (the Netherlands and Germany) with similar building traditions, climate and solar conditions. All the examples demonstrate architectural concepts that integrate photovoltaic as a natural part of the building envelope. (BA)

Energy Technology Data Exchange (ETDEWEB)

Pollen from four temperate-latitude taxa were treated with UV radiation in a portion of the UV-B (280-320 nm) waveband during in vitro germination. Inhibition of germination was noted in this pollen compared to samples treated identically except for the exclusion of the UV-B portion of the spectrum. Levels similar to maximum solar UV-B found in temperate-latitude areas failed to inhibit pollen germination significantly, while levels similar to maximum solar UV-B found in equatorial alpine locations caused partial inhibition of germination in three of the four taxa examined.

Energy Technology Data Exchange (ETDEWEB)

A solar cell structure is produced by a method comprising baking the solar cell, containing a gridded top layer of cuprous sulfide formed on a base of cadmium sulfide, for 20 minutes to 10 hours, to produce a copper doped cds electrically insulating region in the cadmium sulfide base near the interface of the cuprous sulfide and the cadmium sulfide; removing the cuprous sulfide, and the copper doped cds insulating region not covered by the grid, to provide a bare cadmium sulfide areas; and then forming a cuprous sulfide layer on the exposed areas not covered by the grid.

Energy Technology Data Exchange (ETDEWEB)

An improved hybrid solar/combustion powered receiver of the type having an insulated housing with a front end and a rear end, a heat exchanger positioned adjacent the rear housing end for extracting heat energy out of the receiver, the insulated housing surrounding the heat exchanger and forming a receiver cavity, the housing also including an aperature having an aperture axis, the aperture located in the front housing end for admitting solar radiation to the cavity to impinge upon the heat exchanger, and a plurality of gas burners to provide combustion gases within the receiver.

Energy Technology Data Exchange (ETDEWEB)

Asymmetrical solar concentrators may offer significant advantages over symmetrical ones by the higher yearly average energy input per unit aperture area and the wider range of flexibilities in the design and operation. This paper describes the design, construction and performance evaluation of a non-parabolic asymmetrical solar concentrator with an evacuated receiver. The concentrator has a concentration ratio of 3.25 and a theoretical optical efficiency of 0.67. Collector efficiency test results are presented and compared with another similar concentrator without an evacuated receiver.

Energy Technology Data Exchange (ETDEWEB)

Solar energy can be economically converted into electrical energy for small and medium power outputs. A typical solar power plant consists of a parabolic dish, cavity receiver and gas turbine. To obtain high gas turbine efficiencies, the working fluid used has to be heated to high temperatures. This necessitates the use of expensive high-quality materials for the tubes in the receiver. This expense must be kept to a minimum. The present paper demonstrates how this aim can be achieved by meeting the so-called Bammert Criterion.

Energy Technology Data Exchange (ETDEWEB)

This paper presents a mathematical model to analyze the solar evaporation in a shallow pond in steady state, when the inlet flow rate, concentration, surface area and solar radiation are given. The simultaneous heat and mass transfer mechanisms are considered for quantifying the amount of evaporated water to the atmosphere and the actual absorbed heat by wastewater is calculated to obtain the bottom temperature of water pond. The heat losses to air by radiation and convection mechanisms are considered and the heat transmission across the water film is evaluated by the forced convection mechanism. 6 refs., 5 figs., 1 tab.

British Library Electronic Table of Contents (United Kingdom)

This paper presents a two-stage solar multi-effect humidification dehumidification desalination process plotted from pinch analysis. The sketch of two-stage solar multi-effect humidification dehumidification desalination process is given. The solar vacuated tube collector is employed in the desalination system, multi-effect humidification dehumidification desalination (HDD) process are plotted two different temperature range according to pinch technology. The higher temperature range is from 60 to 80?C, and the lower is from 30 to 60?C. The mass flow rates of dry air in the two stage desalination units are different. The pinch analysis chart is given. According to the pinch chart, the energy recover rate could get higher according to working temperature range. The research proves that the ...

Science.gov (United States)

Canada will provide telescope baffles and fine error sensor assemblies. ..... ( Ongoing) Flight tests aboard sounding rockets and balloon planned for FY 1995. .... the effects of incoming energetic particles and solar radiation on the ...

International Nuclear Information System (INIS)

Off-grid power generation is meant to supply remote or rural area, where grid connection is almost impossible in terms of cost and geography, such as island, aborigine's villages, and areas where nature preservation is concern. Harnessing an abundance renewable energy sources using versatile hybrid power systems can offer the best, least-cost alternative solution for extending modern energy services to remote and isolated communities. The conventional method for off-grid power generation is using diesel generator with a renewable energy (RE) technology utilizing solar photovoltaic, wind, biomass, biogas and/or mini/micro hydro. A hybrid technology is a combination of multiple source of energy; such as RE and diesel generator and may also include energy storage such as battery. In our design, the concept of solar hybrid system is a combination of solar with diesel genset and battery as an energy storage. The main objective ...

Science.gov (United States)

This invention is an improved solar energy cavity receiver for exposing materials and components to high temperatures. The receiver includes a housing having an internal reflective surface defining a cavity and having an inlet for admitting solar radiation thereto. A photothermal absorber is positioned in the cavity to receive radiation from the inlet. A reflective baffle is positioned between the absorber and the inlet to severely restrict the re-radiation of energy through the inlet. The front surface of the baffle defines a narrow annulus with the internal reflective surface of the housing. The front surface of the baffle is contoured to reflect incoming radiation onto the internal surface of the housing, from which it is reflected through the annulus and onto the front surface of the absorber. The back surface of the baffle intercepts infrared radiation from the front of the absorber. With this arrangement, a high percentage of the ...

Science.gov (United States)

COATINGS FOR THE METAL-SEMICONDUCTOR SOLAR CELLS 3S GIVEN. THIS METHOD UTILIZES THE MEASURED EQUIVALENT INDEX OF. REFRACTION OBTAINED FROM ELLIPSOMETRY ...

Science.gov (United States)

We here at Blueshift do our best to cover all things astrophysics, which we rather loosely define as 'anything and everything outside the Solar System. ...

Science.gov (United States)

Previous experimental data and theoretical analysis have demonstrated that ... products of a technological process) but also other contaminants. ..... Thorough outgassing of solar array surfaces may result in significant decrease of arc ...

Science.gov (United States)

Because of its direct energy conversion techniques, AMTEC is the front runner today. However, because these systems are now only in the preliminary design ...

Energy Technology Data Exchange (ETDEWEB)

Cavity type receivers are used extensively in concentrating solar thermal energy collecting systems. The Solar Total Energy Project (STEP) in Shenandoah, Georgia is a large scale field test for the collection of solar thermal energy. The STEP experiment consists of a large field array of solar collectors used to supplement the process steam, cooling and other electrical power requirements of an adjacent knitwear manufacturing facility. The purpose of the tests, conducted for this study, was to isolate and quantify the radiative, conductive, and convective components of total heat loss, and to determine the effects of operating temperature, receiver angle, and aperture size on cavity heat loss. An analytical model for radiative heat loss was developed and compared with two other methods used to determine radiative heat loss. A proposed convective heat loss correlation, including effects of aperture size, ...

Science.gov (United States)

LASERASSISTED SOLAR CELL METALLIZATION PROCESSING DOE/JPL/956615--84/3. S. Dutta and P. G. McMullin. Quarterly Report for the period March 13 ...

Energy Technology Data Exchange (ETDEWEB)

Thermophotovoltaic energy conversion achieves direct conversion of thermal energy to electricity without the need for complex dynamic machinery operating in one of several possible thermodynamic cycles. This paper presents an analysis of a hybrid solar thermophotovoltaic (STPV) energy conversion system in which a receiver/photovoltaic (PV) array subsystem is powered by either a solar concentrator or a fossil fuel combustion source. The overall TPV system efficiency is calculated using an appropriate selective emitter and a spectrally tuned solar cell designed to achieve maximum conversion efficiency in the narrow band emitted by the selective emitter. Two limiting cases are examined to place upper and lower bounds on system performance. The estimates of system performance are based on actual experimental data from PV cells and selective emitters.

Energy Technology Data Exchange (ETDEWEB)

The economy of medicinal plant production is burdened considerably by the energy costs of drying. To substitute fossil energy, a solar heated dryer was developed, taking a plastic film greenhouse as superstructure to lower the initial costs. The solar air heaters, being incorporated into the roof, consist of a black absorber tissue, which is placed between the transparent cover of the greenhouse and an insulating air-bubble foil. To obtain a modular design, the system is structured along the ridge into segments of 2 m width. Each segment forms an independent solar air heater/batch dryer unit and is operated by a fan with a power consumption of 500 W. A prototype was tested in Yugoslavia, drying mint, sage and hops. (author).

Science.gov (United States)

shading trellis. This array powers all of the electric appliances, including an oven, cooktop, dishwasher, clothes washer and dryer, home entertainment systems (television and...

Science.gov (United States)

... A detailed analysis of QCM errors is ... Surface Effects of Satellite Outgassing Products." AIAA Journal ... 9. Rauschenbach, H. S. Solar Cell Array Design ...

Energy Technology Data Exchange (ETDEWEB)

Today's building industry is promoting the use of renewable sources of energy to heat, cool, and illuminate commercial buildings. Societies such as the International Solar Energy Society sponsor conferences such as this one to share knowledge and experience in the area of solar energy. However, the technologies presented here assume a need for heating, cooling or illumination. A simple technique is presented for determining the actual heating, cooling, and lighting requirements for commercial buildings, and for reducing those requirements through proper building design before applying solar technologies. The energy nomographs are a graphic energy design tool developed to aid designers in making cost effective decisions about energy alternatives early in the design process. Reducing loads at this point can help reduce the expense of a passive or active solar system which is usually sized to meet ...

British Library Electronic Table of Contents (United Kingdom)

Developing a test standard/protocol for solar box type cookers has drawn a considerable interest among the researchers throughout the world. Recent publications on solar cookers emphasize the need of introducing the thermal performance indicators determined through exergy analysis. In the present paper, the time variation of instantaneous exergy output and energy output as function of its temperature and also of the instantaneous ambient temperature have been reported for truncated pyramid type solar box cooker and compared with those of box type cooker. Further, variations in the exergy lost with temperature difference have been depicted for the selected water temperature range from 60 degreeC to 95 degreeC. Based on this study, quality factor, exergy temperature difference gap product, a...

Energy Technology Data Exchange (ETDEWEB)

This thesis deals with the evaluation of Solar Grade Silicon (SoG-Si) purified by different techniques, and also the fabrication and characterization of high efficiency and advanced bifacial solar cells. In the beginning of Chapter 1, various SoG-Si production methods relevant for this work are qualitatively described. The three feedstock materials used in this work are from the Fluidized Bed Reactor (FBR) process, metallurgical feedstock-I and feedstock-II process. In metallurgical feedstock-I, the lifetime of the minority charge carriers in multicrystalline silicon (mc-Si) samples at the grain boundaries are found to be higher than the grains themselves possibly due to lower resistivities in the grain boundaries. The efficiency of the best solar cell obtained using the mc-Si metallurgical feedstock-I is 16.1%. It has been identified that the fast light induced degradation, whose magnitude is lower than that of a reference ...

Energy Technology Data Exchange (ETDEWEB)

The failure of receivers has been one of the main operating problems at the White Cliffs solar thermal power plant. This Technical Note reports the results of an initial investigation that identifies the cause as having been their thermal fatiguing of the tube walls. The fatigue appears to be caused by unstable heat transfer at vapor qualities below the point where critical heat flux is generally exceeded. Methods for avoiding this problem are tested.

Energy Technology Data Exchange (ETDEWEB)

A solar unit is described which contains a cavity radiation receiver, parabolic-cylindrical concentrator, and reflector arranged between the radiation receiver and the concentrator symmetrically in relation to the optical plane of the latter. In order to expand the range of use, it contains a pair of flat mirrors with 2 working surfaces installed at an angle and symmetrically to the optical plane of the parabolic cylindrical concentrator between them and the reflector, while the latter is made in the form of 2 flat mirrors installed at an angle on the cavity radiation receiver.

Energy Technology Data Exchange (ETDEWEB)

The interest in efficient solar collector design has stimulated investigation of two-dimensional (trough-like) cavity structures. A novel principle for designing cavity enclosures is described. The present method maintains high transmission albeit at the expense of some concentration in the presence of gaps as large as the radius between reflector and receiver. The new method can be applied to advantage to nonimaging concentrator design as well as to line focus concentrators.

Science.gov (United States)

We study the daily incidence of myocardial infarction deaths in Mexico for 4 years (1996-99) with a total of 129 917 cases in all the country, collected at the General Directorate of Epidemiology (National Ministry of Health). We divided the cases by sex and age and perform two kinds of analysis. First, we did an spectral analysis using the Maximum Entropy Method, considering the complete period, and minimum and maximum epochs of solar activity. The results show that the most persistent periodicity at higher frequencies in the myocardial infarction death occurrence is that of seven days. Considering the solar cycle phases, we found that during solar minimum times some frequencies are not detectable compared with solar maximum epochs, particularly that of seven days. Biological rhythms close to seven days, the circaseptans, are in general thought to be only the result of the social organization of life. ...

Energy Technology Data Exchange (ETDEWEB)

The NREL Sensitized Solar Cell (SSC) Core Program supports the Solar America Initiative by: (1) targeting new devices and processes for commercialization by 2015 that are less expensive, more efficient, highly reliable, and environmentally benign; (2) collaborating with DOE OS/BES to conduct basic research targeting breakthroughs in key areas, such as ultra-high efficiency and/or ultra-low cost materials and devices.

Energy Technology Data Exchange (ETDEWEB)

A gas diffusion semiconductor electrode and solar cell and a process for gaseous fixation, such as nitrogen photoreduction, CO/sub 2/ photoreduction and fuel gas photo-oxidation are described. The gas diffusion photosensitive electrode has a central electrolyte porous matrix with an activated semiconductor material on one side adapted to be in contact with an electrolyte and a hydrophobic gas diffusion region on the opposite side adapted to be in contact with a supply of molecular gas.

Energy Technology Data Exchange (ETDEWEB)

Theoretical and experimental results of investigating a cylindrical heat receiver with secondary reflectors are presented. One important element of solar thermal power plants (STPP) is the heat receiver. Several forms of heat receiver exist; the main form is the heat receiver of cavity form (including cylindrical, rectangular, and cubic heat receivers with a noncircular aperture). The linear dimension of such heat receivers is equal to, or larger than, the theoretical diameter of the concentrator focal spot.

Energy Technology Data Exchange (ETDEWEB)

This is an executive summary of a final subcontract report that describes the successful completion of a closed-loop demonstration of a regenerative thermoelectromechanical device using solar heat input for the production of electricity. The full report, which contains a detailed description of the two-year effort, is currently subject to a government secrecy order which precludes public release of the information. Copies of the full report will be made available for general release whenever the secrecy order is lifted.

Energy Technology Data Exchange (ETDEWEB)

The National Center for Photovoltaics sponsored the 17th Workshop on Crystalline Silicon Solar Cells & Modules: Materials and Processes, held in Vail, CO, August 5-8, 2007. This meeting provided a forum for an informal exchange of technical and scientific information between international researchers in the photovoltaic and relevant non-photovoltaic fields. The theme of this year's meeting was 'Expanding Technology for a Future Powered by Si Photovoltaics.'

Energy Technology Data Exchange (ETDEWEB)

The main objective of the present study is twofold: (i) to analyze thermal loads of the geothermally and passively heated solar greenhouses; and (ii) to investigate wind energy utilization in greenhouse heating which is modeled as a hybrid solar assisted geothermal heat pump and a small wind turbine system which is separately installed in the Solar Energy Institute of Ege University, Izmir, Turkey. The study shows 3.13% of the total yearly electricity energy consumption of the modeled system (3568 kWh) or 12.53% of the total yearly electricity energy consumptions of secondary water pumping, brine pumping, and fan coil (892 kWh) can be met by using small wind turbine system (SWTS) theoretically. According to this result, modeled passive solar pre heating technique and combined with geothermal heat pump system (GHPS) and SWTS can be economically preferable to the conventional space heating/cooling systems ...

Energy Technology Data Exchange (ETDEWEB)

III-V semiconductors, GaAs and in particular InGaP, are used in many different electronic applications, such as high power and high frequency devices, laser diodes and high brightness LED. Their direct bandgap and high reliability make them ideal candidates for the realisation of high efficiency solar cells: in the past years they have been successfully used as power sources for satellites in space, where they are able to produce electricity from sunlight with an overall efficiency of around 30%. Nowadays, the use of arsenides and phosphides as photovoltaic (PV) devices is confined only to space applications since their price is much higher than conventional Si flat panel modules, the leading PV market technology. But with the introduction of multijunction solar cells capable of operating in high concentration solar light, the area and, therefore, the cost of these cells can be reduced and will eventually find an ...

International Nuclear Information System (INIS)

We present 14 years of contemporaneous photometric and spectroscopic observations of 28 solar analog stars, taken with the Tennessee State University Automatic Photometric Telescopes at Fairborn Observatory and the Solar-Stellar Spectrograph at Lowell Observatory. These are the best observed and most nearly Sun-like of the targets in our magnitude-limited (V #<=# 7.5) sample. The correlations between luminosity and activity reveal the expected inverse activity-brightness correlations for active stars. Strong direct correlations between activity and brightness are not prevalent for the less active solar age stars, but are precision limited. The Sun does not appear to have unusually low photometric variability when compared with the most Sun-like inactive solar analogs. We present evidence that the activity index R'_H_K is not a good discriminant of Maunder Minimum candidate stars. On the basis of a ...

Energy Technology Data Exchange (ETDEWEB)

Last year a team of US and French scientists using the Odeillo (France) 1MW/sub th/ solar furnace showed concentrated solar radiation to be an effective means for rapidly volatilizing biomass materials. The results of continuing research in the U.S. on radiant flash pyrolysis of biomass as a source of fluid fuels, industrial feedstocks and chemicals are described. Bench scale sources of intense, visible radiant energy have been used to simulate the concentrated solar flux available at the focus of solar towers. Windowed transport reactors are being developed, which act as cavity receivers for the focused radiant energy and provide a means for direct use of the radiation to rapidly pyrolyze the entering biomass. One of these reactors will be operated at the focus of the Georgia Tech 400kW/sub th/ solar furnace next August. Preliminary results from the bench scale reactor experiments, ...

Science.gov (United States)

New comparative tests on two different types of solar collectors are presented in this paper. A standard glazed flat plate collector and an evacuated tube collector are installed in parallel and tested at the same working conditions; the evacuated collector is a direct flow through type with external compound parabolic concentrator (CPC) reflectors. Efficiency in steady-state and quasi-dynamic conditions is measured following the standard and it is compared with the input/output curves measured for the whole day. The first purpose of the present work is the comparison of results in steady-state and quasi-dynamic test methods both for flat plate and evacuated tube collectors. Besides this, the objective is to characterize and to compare the daily energy performance of these two types of collectors. An effective mean for describing and analyzing the daily performance is the so called input/output diagram, in which the collected solar energy is ...

Energy Technology Data Exchange (ETDEWEB)

A wider use of renewable energy sources is considered to be the solution to fossil fuel depletion and environmental pollution. This paper discusses various design considerations for line focussing technology to achieve high efficiency and the possibility of generating power in the megawatt range based on solar thermal technologies. The impacts on the environment of conventional thermal power plants is outlined and an estimate made of the cost of pollution abatement measures. A cost benefit analysis is made using a typical 200 megawatt solar thermal plant, 500 km from the load centre, compared with a 220 megawatt coal fired and a similar capacity gas fired power plant, as examples. The results indicated that the energy from the solar thermal power plant is almost twice as expensive compared to conventionally generated electricity. If, however, impacts on the environment and notional cost associated with are considered, ...

Energy Technology Data Exchange (ETDEWEB)

The use of concentrated solar energy for co-producing Zn and synthesis gas from Zn O and natural gas upgrades the calorific value of the initial reactants by 39% and, when compared to the traditional carbothermic reduction of Zn O, has the potential of reducing CO{sub 2} emissions by up to 78%. An economic assessment for an industrial thermochemical plant, 30 to 51 MW solar input, indicates that the cost of solar production of zinc ranges between 89-133 $/t (excluding the cost of Zn O feed and credit for pollution abatement), and thus might be competitive with conventional fossil-fuel-based processes at current fuel prices. The cost of solar H{sub 2}, produced by splitting water with zinc, is estimated to be in the range 0.10-0.14 $/kWh, and it is a favorable long term prospect once the cost of energy will account for the environmental externalities from fossil fuel burning such as the costs for CO{sub ...

Energy Technology Data Exchange (ETDEWEB)

Progress in the development of high-efficiency GaAs solar cells on low-cost, large-area, large-grain, optical-grade polycrystalline Ge substrates is described in this paper. First, we present results on the growth of specular GaAs-AlGaAs layers, across the various crystalline orientations of a polycrystalline Ge substrate, by metallorganic chemical vapor deposition (MOCVD). Second, we present the preliminary optimization of minority-carrier properties of GaAs-AlGaAs structures on poly-Ge substrates towards the improvement of GaAs solar cells. We have demonstrated comparable minority-carrier lifetimes in GaAs double-hetero structures grown on optical-grade poly-Ge substrates and electronic-grade single-crystal Ge substrates. In addition, we describe device-structure optimization that have led us to achieve a open-circuit voltage of {approximately}1 Volt in a GaAs solar cell on poly-Ge and to improve our previous best ...

Energy Technology Data Exchange (ETDEWEB)

The convection heat loss from cavity receiver in parabolic dish solar thermal power system can significantly reduce the efficiency and consequently the cost effectiveness of the system. It is important to assess this heat loss and subsequently improve the thermal performance of the receiver. This paper aims to present a comprehensive review and systematic summarization of the state of the art in the research and progress in this area. The efforts include the convection heat loss mechanism, experimental and numerical investigations on the cavity receivers with varied shapes that have been considered up to date, and the Nusselt number correlations developed for convection heat loss prediction as well as the wind effect. One of the most important features of this paper is that it has covered numerous cavity literatures encountered in various other engineering systems, such as those in electronic cooling devices and buildings. The studies related to those applications ...

Energy Technology Data Exchange (ETDEWEB)

The United States and Russia have agreed to jointly develop a solar dynamic (SD) system for flight demonstration on the Russian Mir space station starting in late 1997. Two important components of this SD system are the solar concentrator and heat receiver provided by Russia and the US, respectively. This paper describes optical analysis of the concentrator and solar flux predictions on target receiver surfaces. The optical analysis is performed using the code CIRCE2. These analyses account for finite sun size with limb darkening, concentrator surface slope and position errors, concentrator petal thermal deformation, gaps between petals, and the shading effect of the receiver support struts. The receiver spatial flux distributions are then combined with concentrator shadowing predictions. Geometric shadowing patterns are traced from the concentrator to the target receiver surfaces. These patterns vary with time depending on ...

CERN Document Server

We study the high-energy emission of the Galactic black hole candidate GX 339-4 using INTEGRAL/SPI and simultaneous RXTE/PCA data. By the end of January 2007, when it reached its peak luminosity in hard X-rays, the source was in a bright hard state. The SPI data from this period show a good signal to noise ratio, allowing a detailed study of the spectral energy distribution up to several hundred keV. As a main result, we report on the detection of a variable hard spectral feature (>150 keV) which represents a significant excess with respect to the cutoff power law shape of the spectrum. The SPI data suggest that the intensity of this feature is positively correlated with the 25 - 50 keV luminosity of the source and the associated variability time scale is shorter than 7 hours. The simultaneous PCA data, however, show no significant change in the spectral shape, indicating that the source is not undergoing a canonical ...

Energy Technology Data Exchange (ETDEWEB)

The reduction of transient enhanced diffusion (TED) with reduced implantation energy has been investigated and quantified. A fixed dose of 1{times}10{sup 14} cm{sup {minus}2} Si{sup +} was implanted at energies ranging from 0.5 to 20 keV into boron doping superlattices and enhanced diffusion of the buried boron marker layers was measured for anneals at 810, 950, and 1050{degree}C. A linearly decreasing dependence of diffusivity enhancement on decreasing Si{sup +} ion range is observed at all temperatures, extrapolating to {approximately}1 for 0 keV. This is consistent with our expectation that at zero implantation energy there would be no excess interstitials from the implantation and hence no TED. Monte Carlo modeling and continuum simulations are used to fit the experimental data. The results are consistent with a surface recombination length for interstitials of {lt}10 nm. The data presented here demonstrate that in the range of annealing ...

International Nuclear Information System (INIS)

The formation of porous structures of nanometre size (nanoporous structures) on germanium (Ge) surfaces by focused ion beam (FIB) irradiations was investigated using various FIB conditions such as ion species, irradiation energies, total fluences, fluence rates, and incident angles. FIB-irradiated regions were observed using a scanning electron microscope and an atomic force microscope. It is found that, using a focused Ga ion beam (Ga FIB) at an energy of 100 keV, the irradiated Ge surface swelled up to ion fluence of 2 x 10"1"7 cm"-"2 with nanoporous structures and then was etched for larger fluences. The shape of swollen nanoporous structures depended on the fluence rate and the incident angle of the Ga FIB. However, such porous structures were observed neither for low-energy (15-30 keV) FIB irradiations using Si and Au ions nor for high-energy (200 keV), heavy ion (Au) irradiation. These observations might be helpful in ...

International Nuclear Information System (INIS)

The measurements of the K X-ray intensity ratio I(K#alpha# _2/K#alpha# _1), I(K#beta# _1/K#alpha# _1) and I(K#beta#/K#alpha#) for elements V, Mn, Zn, Tc, Ru, Cd, Xe, Ba, Cs, Hg and Rn were experimentally determined both by photon excitation, in which 59.5 keV #gamma#-rays from a "2"4"1Am and 123.6 keV #gamma#-rays from a "6"0Co were used, and following the radioactive decay of "5"1Cr, "5"5Fe, "6"7Ga, "9"9Tc, "1"1"1In, "1"3"1I, "1"3"3Ba, "1"3"3Xe, "1"3"7Cs, "2"0"1Tl and "2"2"6Ra. K X-rays emitted by samples were counted by a Si(Li) detector with resolution 160 eV at 5.9 keV. Obtained values were compared with the theoretical values. It was observed that present values agree with the previous theoretical and other experimental results.

International Nuclear Information System (INIS)

The localized Pt deposition on Si by 30 keV Ga"+ focused ion beam (FIB), 10 keV electron beam (EB) or dual beams (FIB and EB) using precursor gas has been compared by analysis using a 300 keV Be"2"+ microprobe with a beam spot size of 80 nm. The distribution of deposited Pt, Ga from the ion beam itself, and C from the precursor gas was obtained at and nearby the deposited areas by micro-RBS spectra and RBS mapping. All of the beam processed areas showed a uniform Pt distribution at the deposited areas. The amount of Pt atoms increased with the increase in ion or electron dose due to the decomposition of precursor gas. The thickness of Pt layer by EB is considerably less than that by FIB due to the reduced deposition rate. Ga atoms from the center of processed areas partly redeposited at and nearby the FIB processed areas within #approx#3 #mu#m. The Ga incorporation by dual beam processing was reduced compared with that by ...

International Nuclear Information System (INIS)

Total M shell X-ray production cross section for 11 elements with 69 #<=# Z #<=# 92 have been measured using an incident photon energy of 5.96 keV. Measurements have been performed using an "5"5Fe annular source and a Si(Li) detector. Average M shell fluorescence yield at each incident photon energy has been deduced, using the experimental total M X-ray production cross section and theoretical M shell photoionization cross section. Present experimental results are compared with other experimental and theoretical values. Reasonable agreement (to within 0.3-28%) is typically obtained between present and other experimental and theoretical values.

Science.gov (United States)

The Micro-X instrument is a NASA funded, rocket borne X-ray imaging spectrometer planned for launch in January 2011. An array of Transition Edge Sensors (TESs) will observe incoming photons in the 0.2-3 keV energy band with an energy resolution of 2-4 eV at 1 keV. This will be a substantial improvement over current non-dispersive detectors for X-ray spectroscopy of extended sources and will be the first demonstration of a TES-based microcalorimeter in space. The TESs will utilize the 50 mK stage of an Adiabatic Demagnetization Refrigerator (ADR) as a heat sink, and will be read out by a SQUID time division multiplexer. X-rays will be focused onto the TES array of 128 pixels on a 600 micron pitch by a conically approximated Wolter optic with an effective area of 200 cm2. The spectrometer will have a field of view of 11.8 arcmin. We describe the design and development progress of the instrument.

International Nuclear Information System (INIS)

The decay of "1"0"1Mo to levels in "1"0"1Tc has been studied using the three-parameter (#gamma#-#gamma#-t) coincidence system of HpGe-HpGe detectors. From the coincidence data, the new decay scheme was constructed. The previously reported 104.70, 105.95 and 774.15 keV #gamma# rays were observed, and have been assigned to the decay scheme for the first time. A newly observed 1508.01 keV #gamma# ray has also been assigned to the scheme for the first time. The intensities of #beta#"- and the values of log ft to most levels were calculated

International Nuclear Information System (INIS)

The L-shell x-ray intensity ratios I(L_#beta#)/I(L_#alpha#) and I(L_#gamma#)/I(L_a_l_p_h_a) for elements with 73 #<=# Z #<=# 83 have been measured at photon incident energies of 17.8, 25.8 and 46.9 keV. The emitted x-rays were measured with a Si(Li) detector system. The results for Re, Pt and Tl are being reported for the first time. A comparison is made of the experimental results with the calculated values obtained by using the theoretical x-ray emission rates, subshell ionisation cross sections, subshell fluorescence yields and Coster-Kronig transition probabilities. The experimental results are in reasonable agreement with the theoretical values. (author).

Energy Technology Data Exchange (ETDEWEB)

Research preformed consisted of: (1) publication of an experimental paper for the n + {sup 40}Ar high resolution total cross section and submission of a theoretical paper dealing with the prediction of the average parameters deduced from the the data; (2) preliminary R-matrix analysis of the neutron total cross section data for the n + {sup 208}Pb systems, up to an energy of 1.7 MeV; (3) completed the analysis of neutron total cross section of data for n + {sup 54}Fe up to energy of 500 keV, with j{sup {pi}} values confirmed, in most cases, by differential scattering data; (4) analysis of total cross section data for the n + {sup 88}Sr system up to an energy of 175 keV; (5) development of a graphical interface for the code RFUNC, used to calculate the differential scattering cross sections, for comparison with measurements.

International Nuclear Information System (INIS)

An ytterbium-169 high dose rate brachytherapy source, distinguished by an intensity-weighted average photon energy of 92.7 keV and a 32.015#+-#0.009 day half-life, is characterized in terms of the updated AAPM Task Group Report No. 43 specifications using the MCNP5 Monte Carlo computer code. In accordance with these specifications, the investigation included Monte Carlo simulations both in water and air with the in-air photon spectrum filtered to remove low-energy photons below 10 keV. TG-43 dosimetric data including S_K, D(r,#theta#), #LAMBDA#, g_L(r), F(r,#theta#), #phi#_a_n(r), and #phi#_a_n were calculated and statistical uncertainties in these parameters were derived and calculated in the appendix.

Energy Technology Data Exchange (ETDEWEB)

The optical emission of excited H reflected from clean Cu(110) after impingement of H/sup +/ and H/sub 2//sup +/ in the energy range of 250 eV to 20 keV per nucleon at 70/sup 0/ angle of incidence to the surface normal was measured. For incident 10 keV H/sub 2//sup +/, the highest excited hydrogen state detected was the n=10 level. The Hsub(..cap alpha..) yield was found to be fluence and energy dependent. This effect is attributed either to fast sputtered hydrogen, surface roughness or to an increase with hydrogen concentration in electron states of p-like symmetry near the Fermi level of copper. The Hsub(..cap alpha..) yield per reflected nucleon shows approximately an exponential dependence on both projectile energy per nucleon and scattered particle reciprocal velocity perpendicular to the surface.

Energy Technology Data Exchange (ETDEWEB)

We report on recent studies of the effects of 50 keV focused ion beam (FIB) exposure on MOS transistors. We demonstrate that the changes in value of transistor parameters (such as threshold voltage, V{sub t}) are essentially the same for exposure to a Ga+ ion beam at 30 and 50 keV under the same exposure conditions. We characterize the effects of FIB exposure on test transistors fabricated in both 0.5 {micro}m and 0.225 {micro}m technologies from two different vendors. We report on the effectiveness of overlying metal layers in screening MOS transistors from FIB-induced damage and examine the importance of ion dose rate and the physical dimensions of the exposed area.

Energy Technology Data Exchange (ETDEWEB)

The measurements of the K X-ray intensity ratio I(K{sub {beta}})/I(K{sub {alpha}}) for the 17 elements Mn, Fe, Co, Ni, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Y, Zr, Nb and Mo have been done following ionization by 59.5keV {gamma}-rays from a {sup 241}Am point source. Ratios of emission probabilities of Auger electrons and the vacancy transfer coefficients have been extracted in terms of the intensity ratios. It is found that the present results agree well with earlier fitted values and the semi-empirical values.

Energy Technology Data Exchange (ETDEWEB)

We review our recent work on an atomistic approach to the development of predictive process simulation tools. First principles methods, molecular dynamics simulations, and experimental results are used to construct a database of defect and dopant energetics in Si. This is used as input for kinetic Monte Carlo simulations. C and B trapping of the Si self- interstitial is shown to help explain the enormous disparity in its measured diffusivity. Excellent agreement is found between experiments and simulations of transient enhanced diffusion following 20-80 keV B implants into Si, and with those of 50 keV Si implants into complex B-doped structures. Our simulations predict novel behavior of the time evolution of the electrically active B fraction during annealing.

International Nuclear Information System (INIS)

A numerical and experimental investigation is carried out in a solar thermochemical reactor for the thermal dissociation of ZnO at 2000 K using concentrated solar energy. The reactor consists of a cavity-receiver lined with ZnO particles and directly exposed to high-flux irradiation. A transient heat transfer model is formulated to link the rate of radiation, convection, and conduction heat transfer to the reaction kinetics. The radiosity and Monte Carlo methods are applied to obtain the distribution of net radiative fluxes at the internal surfaces of the reactor cavity and at the surface of the ZnO bed. Validation is accomplished in terms of the calculated and measured transient temperature profiles and chemical reaction rates.

British Library Electronic Table of Contents (United Kingdom)

The antimicrobial activity of simulated solar disinfection (SODIS) in the presence and absence of riboflavin against various protozoa and helminth organisms was investigated in this study. Assays were conducted in transparent 12 well microtitre plates containing a suspension of test organisms in the presence or absence of 250mM riboflavin. Plates were exposed to simulated sunlight at an optical irradiance of 550Wm^-^2 (watts per square metre) delivered from a SUNTEST(TM) CPS+ solar simulator. Aliquots of the test suspensions were taken at set time points and the viability of the test organisms was determined by either culture, microscopy or flow cytometry where applicable. With Acanthamoeba, Naegleria, Entamoeba and Giardia exposure to SODIS at an optical irradiance of 550Wm^-^2 for up to ...