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  • 1
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    Roundoff noise analysis for digital Doppler processors in radar scatterometers (1986)
    In:  Other Sources
    Details
    Publication Date: 2013-08-29
    Description: The noise due to finite word length effects for digital Doppler processors (DPP) in radar scatterometers, is analyzed. The roundoff noise-to-signal ratio in the measurement of the radar return signal power is derived. Computer simulations which validate the analytical results are presented. The results can be used in tradeoff studies of hardware design such as number of bits required at each processing stage. The results are used in the design of a DPP for the NASA scatterometer planned to be launched in 1990.
    Keywords: COMMUNICATIONS AND RADAR
    Type: ESA Proceedings of the 1986 International Geoscience and Remote Sensing Symposium (IGARSS '86) on Remote Sensing: Today's Solutions for Tomorrow's Information Needs, Volume 1; p 579-584
    Format: text
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  • 2
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    Kinetic Study of Methyl Acetate Oxidation in a Pt/Al2O3 Fixed-Bed Reactor (1994)
    In:  CASI
    Details
    Publication Date: 2004-10-30
    Description: To support technology development for future long-term missions, a metabolic simulator will be used in a closed chamber to test the functions of a Controlled Ecological Life Support System (CELSS). Methyl acetate (MA) was selected as the fuel because its metabolic respiratory quotient is near that of humans. A kinetic study of the catalytic oxidation of MA over Pt/Al203 was then conducted to support the design and operation of the simulator. Kinetic data were obtained as a conversion percentage of MA versus retention time. The reaction was studied at one atmosphere and temperatures from 220 to 340 deg. C. The inlet MA concentration was varied from 100 to 2000 ppm with retention times from 0.01 to 10 sec. A first-order rate law and a Langmuir-Hinshelwood rate equation were tested by nonlinear regression of the kinetic data to estimate rate constants in the rate law. Regression results of the L-H equation explain the kinetic data better than the results of the first-order rate law. A Taguchi experimental design was used to study the effects of temperature, retention time, and concentrations of MA, CO2, and O2 on the conversion of MA. Results indicate that temperature has greatest effect, followed by retention time, and finally MA concentration. It was further determined that the effects of CO2 and O2 concentrations, and the cross effects, are negligible.
    Keywords: Man/System Technology and Life Support
    Type: Dual-Use Space Technology Transfer Conference and Exhibition; Volume 1; 226-235; NASA-CP-3263-Vol-1
    Format: text
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    NASA TECHNICAL REPORTS
  • 3
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    New technologies for solar energy silicon - Cost analysis of BCL process (1980)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: New technologies for producing polysilicon are being developed to provide lower cost material for solar cells which convert sunlight into electricity. This article presents results for the BCL Process, which produces the solar-cell silicon by reduction of silicon tetrachloride with zinc vapor. Cost, sensitivity, and profitability analysis results are presented based on a preliminary process design of a plant to produce 1000 metric tons/year of silicon by the BCL Process. Profitability analysis indicates a sales price of $12.1-19.4 per kg of silicon (1980 dollars) at a 0-25 per cent DCF rate of return on investment after taxes. These results indicate good potential for meeting the goal of providing lower cost material for silicon solar cells.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Energy; 24; 4, 19; 1980
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  • 4
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    New technologies for solar energy silicon - Cost analysis of dichlorosilane process (1981)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A reduction in the cost of silicon for solar cells is an important objective in a project concerned with the reduction of the cost of electricity produced with solar cells. The cost goal for the silicon material is about $14 per kg (1980 dollars). The process which is currently employed to produce semiconductor grade silicon from trichlorosilane is not suited for meeting this cost goal. Other processes for producing silicon are, therefore, being investigated. A description is presented of results obtained for the DCS process which involves the production of dichlorosilane as a silicon source material for solar energy silicon. Major benefits of dichlorosilane as a silicon source material include faster reaction rates for chemical vapor deposition of silicon. The DCS process involves the reaction 2SiHCl3 yields reversibly SiH2Cl2 + SiCl4. The results of a cost analysis indicate a total product cost without profit of $1.29/kg of SiH2Cl2.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: Solar Energy; 27; 6, 19; 1981
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  • 5
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    Economics of polysilicon processes (1986)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: Techniques are being developed to provide lower cost polysilicon material for solar cells. Existing technology which normally provides semiconductor industry polysilicon material is undergoing changes and also being used to provide polysilicon material for solar cells. Economics of new and existing technologies are presented for producing polysilicon. The economics are primarily based on the preliminary process design of a plant producing 1,000 metric tons/year of silicon. The polysilicon processes include: Siemen's process (hydrogen reduction of trichlorosilane); Union Carbide process (silane decomposition); and Hemlock Semiconductor process (hydrogen reduction of dichlorosilane). The economics include cost estimates of capital investment and product cost to produce polysilicon via the technology. Sensitivity analysis results are also presented to disclose the effect of major paramentes such as utilities, labor, raw materials and capital investment.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: JPL Proceedings of the Flat-Plate Solar Array Project Workshop on Low-Cost Polysilicon for Terrestrial Photovoltaic Solar-Cell Applications; p 79-121
    Format: application/pdf
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  • 6
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    High-performance packaging for monolithic microwave and millimeter-wave integrated circuits (1992)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Packaging schemes are developed that provide low-loss, hermetic enclosure for enhanced monolithic microwave and millimeter-wave integrated circuits. These package schemes are based on a fused quartz substrate material offering improved RF performance through 44 GHz. The small size and weight of the packages make them useful for a number of applications, including phased array antenna systems. As part of the packaging effort, a test fixture was developed to interface the single chip packages to conventional laboratory instrumentation for characterization of the packaged devices.
    Keywords: ELECTRONICS AND ELECTRICAL ENGINEERING
    Type: AIAA PAPER 92-1935
    Format: text
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  • 7
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    Estimating three-demensional energy transfer in isotropic turbulence (1980)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: To obtain an estimate of the spectral transfer function that indicates the rate of decay of energy, an x-wire probe was set at a fixed position, and two single wire probes were set at a number of locations in the same plane perpendicular to the mean flow in the wind tunnel. The locations of the single wire probes are determined by pseudo-random numbers (Monte Carlo). Second order spectra and cross spectra are estimated. The assumption of isotropy relative to second order spectra is examined. Third order spectra are also estimated corresponding to the positions specified. A Monte Carlo Fourier transformation of the downstream bispectra corresponding to integration across the plane perpendicular to the flow is carried out assuming isotropy. Further integration is carried out over spherical energy shells.
    Keywords: THEORETICAL MATHEMATICS
    Type: NASA-CR-164217
    Format: application/pdf
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  • 8
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    Process feasibility study in support of silicon material task 1 (1981)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Results for process system properties, chemical engineering and economic analyses of the new technologies and processes being developed for the production of lower cost silicon for solar cells are presented. Analyses of process system properties are important for chemical materials involved in the several processes under consideration for semiconductor and solar cell grade silicon production. Major physical, thermodynamic and transport property data are reported for silicon source and processing chemical materials.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA-CR-164009
    Format: application/pdf
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  • 9
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    Process feasibility study in support of silicon material task 1 (1978)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: Process system properties are analyzed for materials involved in the alternate processes under consideration for solar cell grade silicon. The following property data are reported for trichlorosilane: critical constants, vapor pressure, heat of vaporization, gas heat capacity, liquid heat capacity, density, surface tension, viscosity, thermal conductivity, heat of formation, and Gibb's free energy of formation. Work continued on the measurement of gas viscosity values of silicon source materials. Gas phase viscosity values for silicon tetrafluoride between 40 C and 200 C were experimentally determined. Major efforts were expended on completion of the preliminary economic analysis of the silane process. Cost, sensitivity and profitability analysis results are presented based on a preliminary process design of a plant to produce 1,000 metric tons/year of silicon by the revised process.
    Keywords: ENERGY PRODUCTION AND CONVERSION
    Type: NASA-CR-158034 , ERDA/JPL-954343-78/13 , QTPR-13
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  • 10
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    Application of an optimization method to high performance propeller designs (1984)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The application of an optimization method to determine the propeller blade twist distribution which maximizes propeller efficiency is presented. The optimization employs a previously developed method which has been improved to include the effects of blade drag, camber and thickness. Before the optimization portion of the computer code is used, comparisons of calculated propeller efficiencies and power coefficients are made with experimental data for one NACA propeller at Mach numbers in the range of 0.24 to 0.50 and another NACA propeller at a Mach number of 0.71 to validate the propeller aerodynamic analysis portion of the computer code. Then comparisons of calculated propeller efficiencies for the optimized and the original propellers show the benefits of the optimization method in improving propeller performance. This method can be applied to the aerodynamic design of propellers having straight, swept, or nonplanar propeller blades.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AIAA PAPER 84-1203
    Format: text
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