Results 1 - 10 of 206093
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[en] This proceedings is the compilation of all papers presented at the 11th PV Performance and Reliability Workshop held at the Doubletree Hotel in Cocoa Beach, Florida, on November 3-5, 1998. The workshop was hosted by the Florida Solar Energy Center. This year's workshop included presentations from 29 speakers and had 110 attendees
[en] The efficiency of materials developed for solar energy and technological applications depends on the interplay between molecular architecture and light-induced electronic energy redistribution. The spatial localization of electronic excitations is very sensitive to molecular distortions. Vibrational nuclear motions can couple to electronic dynamics driving changes in localization. The electronic energy transfer among multiple chromophores arises from several distinct mechanisms that can give rise to experimentally measured signals. Atomistic simulations of coupled electron-vibrational dynamics can help uncover the nuclear motions directing energy flow. Through careful analysis of excited state wave function evolution and a useful fragmenting of multichromophore systems, through-bond transport and exciton hopping (through-space) mechanisms can be distinguished. Such insights are crucial in the interpretation of fluorescence anisotropy measurements and can aid materials design. Finally, this Perspective highlights the interconnected vibrational and electronic motions at the foundation of nonadiabatic dynamics where nuclear motions, including torsional rotations and bond vibrations, drive electronic transitions.
[en] We report on the design of two hybrid lighting luminaires that blend light from a fiber optic end-emitted solar source with electric T8 fluorescent lamps. Both designs involve the retrofit of a commercially-available recessed fluorescent luminaire with minimal reductions in the original luminaire's optical efficiency. Two methods for high-angle dispersion of fiber optic end-emitted solar light are described and the resulting spatial intensity distributions, simulated using ZEMAX, are compared with standard cylindrical fluorescent tubes. Differences in spatial intensity distribution are qualitatively characterized and potential design improvements discussed
[en] Geothermal energy is a varied discipline that challenges many separate scientific domains. Geological constraints limit access to thermal reservoirs, strength of materials limits the ability to drill into hot strata, mechanical constraints limit the extraction of energy from fluid at a small temperature difference and environmental concerns restrict the fluids production because of the gases released. These problems are all being investigated, and progress is constant and hopeful. The uses of geothermal energy are varied. They range from direct use in space heating to using geothermal steam to power turbines. Ground source heat pumps are a popular alternative to conventional air conditioning systems, and water source heat pumps are another proven alternative. Many other applications are on the horizon, including absorption chillers able to operate at a small temperature difference, higher tonnage ground source equipment and new approaches to hot dry rock power production
[en] The development of microsatellites requires the development of engines to modify their orbit. It is natural to use solar energy to drive such engines. For an unlimited energy source the optimal thruster must use a minimal amount of expendable material to minimize launch costs. This requires the ejected material to have the maximal velocity and, hence, the ejected atoms must be as light as possible and be ejected by as high an energy density source as possible. Such a propulsion can be induced by pulses from an ultra-short laser. The ultra-short laser provides the high-energy concentration and high-ejected velocity. We suggest a microthruster system comprised of an inflatable solar concentrator, a solar panel, and a diode-pumped fiber laser. We will describe the system design and give weight estimates.
[en] A system and method for thermally regenerating an electrochemical concentration cell are described that has first and second aluminum electrodes, respectively, positioned in contact with first and second electrolytes separated by an ion exchange member, the first and second electrolytes being composed of different concentrations of an ionic solvent and a salt, preferably an aluminum halide. The ionic solvent may be either organic or inorganic with a relatively low melting point, the ionic solvent and the salt form a complex wherein the free energy of formation of said complex is less than about -5 kcal/mole. A distillation column using solar heat or low grade industrial waste heat receives the first and second electrolytes and thermally decomposes the salt-solvent complex to provide feed material for the two half cells
[en] Nucleon self-energies from the pion-ring series are studied in the relativistic mean-field theory of linear σ model with the ω meson and the Δ. Near the Fermi surface of nuclear matter, the pion rings generate attractive scalar and vector potentials of 10--15 % of the nucleon mass. These strongly energy-dependent potentials cause the nucleons to have a significant probability to be in a collective N-hole or Δ-hole configuration
[en] Positive, or at least neutral, community perceptions about, and reactions toward, geothermal development activities are desirable and necessary from exploration permit acquisition throughout the life of a project. This paper reports on developing an informal network of contacts throughout the impacted and adjacent communities with which to initiate and maintain meaningful dialogue and feedback that can be a valuable tool toward this end
[en] Nuclear, Te, Ti Project Briefs describe the status of all RandD programs submitted to the Power Information Center by the government sponsors in energy conversion from fission, fusion, and radioisotope power sources and other thermal systems that use thermionic systems. These briefs also follow related investigations of plasma dynamics. The document is not to be reproduced, in whole or in part, for dissemination outside your own organization nor may it be reproduced for advertising or sales promotion purposes