786 research outputs found
Electricity from photovoltaic solar cells: Flat-Plate Solar Array Project final Report. Volume III: Silicon sheet: wafers and ribbons
The Flat-Plate Solar Array (FSA) Project, funded by the U.S. Government and managed by the Jet Propulsion Laboratory, was formed in 1975 to develop the module/array technology needed to attain widespread terrestrial use of photovoltaics by 1985. To accomplish this, the FSA Project established and managed an Industry, University, and Federal Government Team to perform the needed research and development.
The primary objective of the Silicon Sheet Task of the FSA Project was the development of one or more low-cost technologies for producing silicon sheet suitable for processing into cost-eompetitive solar cells. Silicon sheet refers to high-purity crystalline silicon of size and thickness for fabrication into solar cells.
The Task effort began with state-of-the-art sheet technologies and then solicited and supported any new silicon sheet alternatives that had the potential to achieve the Project goals.
A total of 48 contracts were awarded that covered work in the areas of ingot growth and casting, wafering, ribbon growth, other sheet technologies, and programs of supportive research. Periodic reviews of each sheet technology were held, assessing the technical progress and the long-range potential. Technologies that failed to achieve their promise, or seemed to have lower probabilities for success in comparison with others, were dropped. A series of workshops was initiated to assess the state of the art, to provide insights into problems remaining to be addressed, and to support technology transfer.
The Task made and fostered significant improvements in silicon sheet including processing of both ingot and ribbon technologies. An additional important outcome was the vastly improved understanding of the characteristics associated with high-quality sheet, and the control of the parameters required for higher efficiency solar cells. Although significant sheet cost reductions were made, the technology advancements required to meet the Task cost goals were not achieved.
This FSA Final Report (JPL Publication 86-31, 5101-289, DOE/JPL 1012-125, October 1986) is composed of eight volumes, consisting of an Executive Summary and seven technology reports:
Volume I: Executive Summary.
Volume II: Silicon Material.
Volume III: Silicon Sheet: Wafers and Ribbons
Volume IV: High-Efficiency Solar Celis.
Volume V: Process Development.
Volume VI: Engineering Sciences and Reliability.
Volume VII: Module Encapsulation.
Volume VIII: Project Analysis and Integration.
Two supplemental reports included in the final report package are:
FSA Project: 10 Years of Progress, JPL Document 400-279. 5101-279, October 1985.
Summary of FSA Project Documentation: Abstracts of Published Documents, 1975 to 1986, JPL Publication 82-79 (Revision 1),5101-221, DOE/JPL-1 012-76, September 1986
Hereditary osteopetrosis in aberdeen-angus calves. II. — Genetical aspects
International audienc
Hereditary osteopetrosis in aberdeen-angus calves. I. - Pathological changes
International audienc
Flat-plate solar array project. Volume 3: Silicon sheet: Wafers and ribbons
The primary objective of the Silicon Sheet Task of the Flat-Plate Solar Array (FSA) Project was the development of one or more low cost technologies for producing silicon sheet suitable for processing into cost-competitive solar cells. Silicon sheet refers to high purity crystalline silicon of size and thickness for fabrication into solar cells. Areas covered in the project were ingot growth and casting, wafering, ribbon growth, and other sheet technologies. The task made and fostered significant improvements in silicon sheet including processing of both ingot and ribbon technologies. An additional important outcome was the vastly improved understanding of the characteristics associated with high quality sheet, and the control of the parameters required for higher efficiency solar cells. Although significant sheet cost reductions were made, the technology advancements required to meet the task cost goals were not achieved
Pygomelia or supernumerary limbs in a crossbred calf
A crossbred (Sindhi Ă— local indigenous) calf that was 12 days old was admitted to the Teaching Veterinary Hospital, Chittagong Government Veterinary College, Bangladesh, with two accessory hind limbs attached to the pelvic region in between the hind legs. This was clinically identified as a congenital anomaly popularly called pygomelia. The pygomelia was successfully corrected by surgical excisions
Improved Collective Thomson Scattering measurements of fast ions at ASDEX Upgrade
Understanding the behaviour of the confined fast ions is important in both
current and future fusion experiments. These ions play a key role in heating
the plasma and will be crucial for achieving conditions for burning plasma in
next-step fusion devices. Microwave-based Collective Thomson Scattering (CTS)
is well suited for reactor conditions and offers such an opportunity by
providing measurements of the confined fast-ion distribution function resolved
in space, time and 1D velocity space. We currently operate a CTS system at
ASDEX Upgrade using a gyrotron which generates probing radiation at 105 GHz. A
new setup using two independent receiver systems has enabled improved
subtraction of the background signal, and hence the first accurate
characterization of fast-ion properties. Here we review this new dual-receiver
CTS setup and present results on fast-ion measurements based on the improved
background characterization. These results have been obtained both with and
without NBI heating, and with the measurement volume located close to the
centre of the plasma. The measurements agree quantitatively with predictions of
numerical simulations. Hence, CTS studies of fast-ion dynamics at ASDEX Upgrade
are now feasible. The new background subtraction technique could be important
for the design of CTS systems in other fusion experiments.Comment: 4 pages, 4 figures, to appear in Proc. of "Fusion Reactor
Diagnostics", eds. F. P. Orsitto et al., AIP Conf. Pro
Displaced geostationary orbit design using hybrid sail propulsion
Because of an increase in the number of geostationary spacecraft and the limits imposed by east–west spacing
requirements, the geostationary orbit is becoming congested. To increase its capacity, this paper proposes to create
new geostationary slots by displacing the geostationary orbit either out of or in the equatorial plane by means of
hybrid solar sail and solar electric propulsion. To minimize propellant consumption, optimal steering laws for the
solar sail and solar-electric-propulsion thrust vectors are derived and the performance in terms of mission lifetime is
assessed. For comparison, similar analyses are performed for conventional propulsion, including impulsive and pure
solar electric propulsion. It is shown that hybrid sails outperform these propulsion techniques and that out-of-plane
displacements outperform in-plane displacements. The out-of-plane case is therefore further investigated in a
spacecraft mass budget to determine the payload mass capacity. Finally, two transfers that enable a further
improvement of the performance of hybrid sails for the out-of-plane case are optimized using a direct pseudospectral
method: a seasonal transit between orbits displaced above and below the equatorial plane and a transit to a parking
orbit when geostationary coverage is not needed. Both transfers are shown to require only a modest propellant
budget, outweighing the improvements they can establish
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