16,676 research outputs found

    A digitally controlled very high frequency synthesizer

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    Breadboard model of digitally controlled very high frequency synthesizer for use in aviation navigation receive

    Technique for extending the frequency range of digital dividers

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    A technique for extending the frequency range of a presettable digital divider is described. The conventional digital divider consists of several counter stages with the count of each stage compared to a preselected number. When the counts for all stages are equal to the preselected numbers, an output pulse is generated and all stages are reset. For high input frequencies, the least significant stage of the divider has to be reset in a very short time. This limits the frequency that can be handled by the conventional digital divider. This invention provides a technique in which the second least significant and higher stages are reset and the least significant stage is permitted to free-run. Hence, the time in which the reset operation can be performed is increased thereby extending the frequency range of the divider

    Modeling the light curves of ultraluminous X-ray sources as precession

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    We present a freely available xspec model for the modulations seen in the long-term light curves of multiple ultraluminous X-ray sources (ULXs). By incorporating the physics of multiple electron scatterings (ray traced with a Monte-Carlo routine), we go beyond analytical predictions and show that the geometrical beaming of radiation in the conical outflow can be more than a factor of 100 for opening angles smaller than 10∘10^\circ. We apply our new model to the long-term, well sampled Swift light curve of the recently confirmed ULX pulsar NGC 5907 X-1 with an established period of 78 days. Our results suggest that geometrical beaming together with a slight precession of the conical wind can describe the light curve with a consistent set of parameters for the wind. The small opening angle of roughly 10−13∘10\mathrm{-}13^\circ implies a highly super-critical flow and boosting factors at the order of B=60−90\mathcal{B}=60\mathrm{-}90 that would yield a fairly low surface magnetic field strength of 2×1010 2\times 10^{10}\,Gauss.Comment: accepted by MNRAS for publication (7 pages, 6 figures

    Water Markets in Georgia: An Overview of Ongoing Sales of Water

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    This paper addresses considerations of direct relevance for ongoing debate in the state as to whether or not water should be sold "like a commodity". The primary point made in the paper is that water is and has long been bought and sold as a commodity in the state. Thus, in the author's view the ongoing debate is simply out of touch with reality.This paper presents case studies showing that there are currently wholesale and retail water markets in Georgia. Moreover, such markets have benefitted many Georgians. In each case, the market in water was created in response to the need to support economic development and lower customer's costs. These markets are subject to regulatory oversight, serve the interest of rural communities, and work in concert with the object of planning and managing water resources. Working Paper # 2003-00

    A system for aerodynamic design and analysis of supersonic aircraft. Part 1: General description and theoretical development

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    An integrated system of computer programs was developed for the design and analysis of supersonic configurations. The system uses linearized theory methods for the calculation of surface pressures and supersonic area rule concepts in combination with linearized theory for calculation of aerodynamic force coefficients

    A computational system for aerodynamic design and analysis of supersonic aircraft. Part 1: General description and theoretical development

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    An integrated system of computer programs was developed for the design and analysis of supersonic configurations. The system uses linearized theory methods for the calculation of surface pressures and supersonic area rule concepts in combination with linearized theory for calculation of aerodynamic force coefficients. Interactive graphics are optional at the user's request. Schematics of the program structure and the individual overlays and subroutines are described

    Hydrographic charting from LANDSAT Satellite: A comparison with aircraft imagery

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    The relative capabilities of two remote-sensing systems in measuring depth and, consequently, bottom contours in sandy-bottomed and sediment-laden coastal waters were determined quantitatively. The multispectral scanner (MSS), orbited on the LANDSAT-2 Satellite, and the ocean color scanner (OCS), flown on U-2 aircraft, were used. Analysis of imagery taken simultaneously indicates a potential for hydrographic charting of marine coastal and shallow shelf areas, even when water turbidity is a factor. Several of the eight optical channels examined on the OCS were found to be sensitive to depth or depth-related information. The greatest sensitivity was in OCS-4(0.544 + or - 0.012 microns) from which contours corresponding to depths up to 12m were determined. The sharpness of these contours and their spatial stability through time suggests that upwelling radiance is a measure of bottom reflectance and not of water turbidity. The two visible channels on LANDSAT's MSS were less sensitive in the discrimination of contours, with depths up to 8m in the high-gain mode (3x) determined in MSS-4(0.5 to 0.6 microns)

    Atmospheric variability and air-sea interaction

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    The topics studied include: (1) processing of Northern Hemispheric precipitation data, in order to fill in the transition seasons to provide a continuous 40 year data base on the variability of continental precipitation; (2) comparison of seasonally averaged fields of sea surface temperature obtained from ship observations in the North Atlantic and North Pacific in 1970 with the corresponding fields inferred from satellite observations; (3) estimation of seasonal average of total precipitable water at those admittedly few oceanic stations where repeated vertical soundings were made in 1970 and comparison with corresponding values inferred from satellite measurements; (4) comparison of seasonally averaged evaporation fields determined from ground based observations in 1970 with the field of divergence of the seasonal total horizontal water vapor flux inferred from satellite total water measurements and NMC wind data for the lower troposphere; (5) examination of meaning of convection-inversion index

    Aerodynamic design and analysis system for supersonic aircraft. Part 1: General description and theoretical development

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    An integrated system of computer programs has been developed for the design and analysis of supersonic configurations. The system uses linearized theory methods for the calculation of surface pressures and supersonic area rule concepts in combination with linearized theory for calculation of aerodynamic force coefficients. Interactive graphics are optional at the user's request. This part presents a general description of the system and describes the theoretical methods used

    Circular 17

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    Raise Your Calf Right— Feed your freshening cow / Take care of your freshening cow / Give ihe Calf a good place to live / Teach the calf to drink right away / Start your calf on grain early / Feed your calf roughage within 2 weeks. / Remember water and salt / Keep your heifers growing / -- Raise Your Calf Economically— Compare these rations: Whole milk, Skim milk, Skim milk powder, Gruel, Milk-Flo, Calf Manna, Calf meal / Follow recommended feeding programUnited States Department of Agriculture in cooperation with the Agricultural Research Administratio
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