19,445 research outputs found
Digital correlation of DDRS data
The reduction of digital SAR (synthetic aperture radar) data to radar images for use in remote sensing applications was investigated. The critical software operations are discussed in detail, and suggestions and recommendations are made for improving the algorithms currently being used
APQ-102 imaging radar digital image quality study
A modified APQ-102 sidelooking radar collected synthetic aperture radar (SAR) data which was digitized and recorded on wideband magnetic tape. These tapes were then ground processed into computer compatible tapes (CCT's). The CCT's may then be processed into high resolution radar images by software on the CYBER computer
Development of a ground signal processor for digital synthetic array radar data
A modified APQ-102 sidelooking array radar (SLAR) in a B-57 aircraft test bed is used, with other optical and infrared sensors, in remote sensing of Earth surface features for various users at NASA Johnson Space Center. The video from the radar is normally recorded on photographic film and subsequently processed photographically into high resolution radar images. Using a high speed sampling (digitizing) system, the two receiver channels of cross-and co-polarized video are recorded on wideband magnetic tape along with radar and platform parameters. These data are subsequently reformatted and processed into digital synthetic aperture radar images with the image data available on magnetic tape for subsequent analysis by investigators. The system design and results obtained are described
Introduction: The Challenge of Risk Communication in a Democratic Society
The symposium editors review key issues concerning the relationship between risk communication and public participation
Dielectronic recombination of W^20+ (4d^10 4f^8): addressing the half-open f-shell
A recent measurement of the dielectronic recombination (DR) of W^20+
[Schippers et al Phys. Rev. A83, 012711 (2011)] found an exceptionally large
contribution from near threshold resonances (<1eV). This still affected the
Maxwellian rate coefficient at much higher temperatures. The experimental
result was found to be a factor 4 or more than that currently in use in the
100-300eV range which is of relevance for modeling magnetic fusion plasmas. We
have carried-out DR calculations with AUTOSTRUCTURE which include all
significant single electron promotions. Our intermediate coupling (IC) results
are more than a factor of 4 larger than our LS-coupling ones at 1eV but still
lie a factor 3 below experiment here. If we assume complete (chaotic) mixing of
near-threshold autoionizing states then our results come into agreement (to
within 20%) with experiment below about 2eV. Our total IC Maxwellian rate
coefficients are 50-30% smaller than those based-on experiment over 100-300eV.Comment: 10 pages, 8 figures, submitted to Phys.Rev.
SELECTING FUNCTIONAL FORM IN PRODUCTION FUNCTION ANALYSIS
Functional form selection is a sometimes neglected aspect of applied research in production analysis. To provide an improved and uniform basis for form selection, a number of traditional and popular functional forms are catalogued with respect to intrinsic properties. Guidelines for the conduct of form selection are also discussed.Production Economics, Research Methods/ Statistical Methods,
Simultaneous measurements of particulate and gas-phase water-soluble organic carbon concentrations at remote and urban-influenced locations
The sources, sinks, and overall importance of watersoluble organic carbon (WSOC) in the atmosphere are not well understood. Although the primary historical focus has been on particulate WSOC (WSOCP), here we also present results obtained using a newly developed technique that additionally measures gas-phase water-soluble organic carbon (WSOCG). These first-of-their-kind measurements show that WSOCG can often be more than ten times larger than WSOCP at both urban and remote locations. The average fraction of WSOC residing in the gas phase (fg = WSOCG/(WSOCG + WSOCP)) at five various field sites ranged from 0.64 to 0.93, implying significant differences in WSOC phase partitioning between locations. At Houston, TX, and Summit, Greenland, a repeatable diurnal pattern was observed, with minimum values for fg occurring at night. These trends likely are due, at least in part, to temperature and/or relative humidity related gas-to-particle partitioning. These coincident measurements of WSOC in both the gas and particle phases indicate that a relatively large reservoir of water-soluble organic mass is not taken into account by measurements focused only on WSOCP. In addition, a significant amount of WSOCG is available to form WSOCP or enter cloud droplets depending on the chemical and physical properties of the droplets and/or aerosols present. Citation: Anderson, C., J. E. Dibb, R. J. Griffin, and M. H. Bergin (2008), Simultaneous measurements of particulate and gas-phase water-soluble organic carbon concentrations at remote and urban-influenced locations, Geophys. Res. Lett., 35, L13706, doi:10.1029/2008GL033966
Multiobjective analysis for the design and control of an electromagnetic valve actuator
The electromagnetic valve actuator can deliver much improved fuel efficiency and reduced emissions in spark ignition (SI) engines owing to the potential for variable valve timing when compared with cam-operated, or conventional, variable valve strategies. The possibility exists to reduce pumping losses by throttle-free operation, along with closed-valve engine braking. However, further development is required to make the technology suitable for accept- ance into the mass production market. This paper investigates the application of multiobjective optimization techniques to the conflicting objective functions inherent in the operation of such a device. The techniques are utilized to derive the optimal force–displacement characteristic for the solenoid actuator, along with its controllability and dynamic/steady state performance
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