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  • 1
    ISSN: 1432-203X
    Keywords: Key words Somatic embryogenesis ; Picea glauca ; Nitrogen nutrition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of glutamine-based dipeptides, glutamine and casein hydrolysate, as well as the deletion of organic nitrogen, were investigated during white spruce [Picea glauca (Moench) Voss] somatic embryogenesis. There were no differences in the fresh weight increase of the tissue masses grown on initiation medium with different combinations of organic nitrogen. This was also the case for subsequent growth on kinetin medium, except that glutamine alone produced a significantly lower fresh weight increase than the other organic nitrogen combinations. Without organic (i.e. with only inorganic) nitrogen in the medium, the fresh weight increase was significantly less than with organic nitrogen on both initiation and kinetin medium. No differences were found between the dry/fresh weight ratios obtained with the various nitrogen treatments. The number of mature embryos produced per gram fresh weight when cultured in the absence of organic nitrogen was significantly higher than that obtained in its presence. There were no differences in the total number of mature embryos produced in cultures grown with various organic nitrogen combinations or without organic nitrogen. There were large clone differences with respect to the number of mature somatic embryos per gram tissue and the total number of somatic embryos produced. Hence, nitrogen type influences culture growth rate but not the number of mature somatic embryos produced. The latter was clone dependent.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-203X
    Keywords: Somatic embryogenesis ; Picea glauca ; Nitrogen nutrition
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The effects of glutamine-based dipeptides, glutamine and casein hydrolysate, as well as the deletion of organic nitrogen, were investigated during white spruce [Picea glauca (Moench) Voss] somatic embryogenesis. There were no differences in the fresh weight increase of the tissue masses grown on initiation medium with different combinations of organic nitrogen. This was also the case for subsequent growth on kinetin medium, except that glutamine alone produced a significantly lower fresh weight increase than the other organic nitrogen combinations. Without organic (i.e. with only inorganic) nitrogen in the medium, the fresh weight increase was significantly less than with organic nitrogen on both initiation and kinetin medium. No differences were found between the dry/fresh weight ratios obtained with the various nitrogen treatments. The number of mature embryos produced per gram fresh weight when cultured in the absence of organic nitrogen was significantly higher than that obtained in its presence. There were no differences in the total number of mature embryos produced in cultures grown with various organic nitrogen combinations or without organic nitrogen. There were large clone differences with respect to the number of mature somatic embryos per gram tissue and the total number of somatic embryos produced. Hence, nitrogen type influences culture growth rate but not the number of mature somatic embryos produced. The latter was clone dependent.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 7 (1987), S. 1013-1033 
    ISSN: 0271-2091
    Keywords: Convection-Diffusion-Reaction Finite Elements Petrov-Galerkin ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: New finite element procedures based on the streamline-upwind/Petrov-Galerkin formulations are developed for time-dependent convection-diffusion-reaction equations. These procedures minimize spurious oscillations for convection-dominated and reaction-dominated problems. The results obtained for representative numerical examples are accurate with minimal oscillations.As a special application problem, the single-well chemical tracer test (a procedure for measuring oil remaining in a depleted field) is simulated numerically. The results show the importance of temperature effects on the interpreted value of residual oil saturation from such tests.
    Additional Material: 12 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    International Journal for Numerical Methods in Fluids 11 (1990), S. 769-790 
    ISSN: 0271-2091
    Keywords: Heterogeneous Equations ; Finite Element ; Residual Oil Saturation ; Single-well Chemical Tracer Test ; Engineering ; Engineering General
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Heterogeneous equation systems in a pair of coupled co-ordinate systems are solved by a finite element method. The specific physical application studied is the effect of temperature on single-well chemical tracer (SWCT) tests to measure residual oil saturation (volume fraction of immobile oil phase) remaining after waterflooding of an oil reservoir. Since temperature effects are caused by injecting cooler surface fluid down a well into a warm reservoir, the vertical temperature profile in the wellbore as well as the temperature distribution in the porous oil-bearing layer must be considered.The entire system is modelled to account for the different transport mechanisms. However, it is expedient to divide the connected geometrical region into two model domains. The equations for each submodel are expressed in an appropriate set of co-ordinates. The variational formulation of each model is then discussed.A significant temperature effect on the estimation of residual oil saturation occurs when the radial temperature and concentration wave propagation speeds in the porous formation are about the same. In this case the temperature gradient is located across the chemical tracer bank, causing the chemical reaction rate to vary radially. The temperature effects are demonstrated for two actual field tests in complex reservoirs.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
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  • 5
    Publication Date: 2011-08-17
    Description: An INTELSAT/DOMSAT double hop bent pipe link for the Venus orbiting imaging radar synthetic aperture radar imaging data transfer from deep space stations 43 and 63 to the Jet Propulsion Laboratory was investigated. The cost for the bent pipe transfer was estimated and compared to that for the planned tape record/airfreight-the-tape transfer method.
    Keywords: COMMUNICATIONS AND RADAR
    Type: The Telecommun. and Data Acquisition Rept.; p 82-90
    Format: text
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  • 6
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    In:  Other Sources
    Publication Date: 2019-06-28
    Description: A design for a low-user-cost, 9000 channel capacity second generation mobile satellite system (Msat-2) for continental U.S., Alaska and Canada using two geostationary satellites at 90 and 130 deg west longitude, is presented. The increased capacity over the first generation system is obtained by use of a 20 m deployable antenna with an offset-fed antenna configuration, a high-power satellite bus, and by relaxing the north-south stationkeeping requirement to + or - 2 deg and the eclipse capability to 50 percent. Efficient frequency utilization is achieved for uplink and downlink spectra by a 7-frequency reuse scheme with 285 5-kHz channels per subband, and subband reuse of up to four times. Problems of interbeam interference and multipath fading contributed to the choice of a nonoverlapping feed for the Msat-2, and a proper modulation scheme using Gaussian baseband filtered minimum-shift-keying with differential detection.
    Keywords: COMMUNICATIONS AND RADAR
    Type: AIAA PAPER 86-0659
    Format: text
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  • 7
    Publication Date: 2019-06-28
    Description: In recent years, interest has grown in the mobile satellite (MSAT) system, a satellite-based communications system capable of providing integrated voice and data services to a large number of users. To explore the potential of a commercial mobile satellite system (MSS) beyond the horizon of the first generation, using technologies of the 1990's and to assist MSAT-X in directing its efforts, a conceptual design has been performed for a second-generation system to be launched around the mid-1990's. The design goal is to maximize the number of satellite channels and/or minimize the overall life-cycle cost, subject to the constraint of utilizing a commercial satellite bus with minimum modifications. To provide an optimal design, a series of trade-offs are performed, including antenna sizing, feed configurations, and interference analysis. Interference is a serious problem for MSAT and often an overlapping feed design is required to reduce interbeam interference. The trade-off studies will show that a simple non-overlapping feed is sufficient for the second-generation system, thus avoiding the need for the complicated beam-forming network that is associated with the overlapping feed designs. In addition, a system that operates at L-band, an alternative frequency band that is being considered by some for possible MSAT applications, is also presented.
    Keywords: COMMUNICATIONS AND RADAR
    Type: NASA-CR-176195 , NAS 1.26:176195
    Format: application/pdf
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  • 8
    Publication Date: 2019-07-13
    Description: Carrier tracking performance of the polarity type costas loop is analyzed for unbalanced quadriphase-shift-keyed (UQPSK) signals at low SNR. Squaring losses for various SNR, IF bandwidth, and data rate ratios are presented. The RMS phase jitter for a particular loop is computed for various I and Q channel power and data rate ratios. Experimental results using a breadboard costas loop are also included.
    Keywords: COMMUNICATIONS AND RADAR
    Type: In: ICC ''81; International Conference on Communications; Jun 14, 1981 - Jun 18, 1981; Denver, CO
    Format: text
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  • 9
    Publication Date: 2019-07-13
    Description: In this paper, the feasibility of a multi-channel sound broadcasting satellite system for operation in a band between 0.5 and 2.0 GHz is investigated. Considered are sound broadcasting satellite systems that provide conventional FM sound broadcasting for individual receivers in a wide geographical area. Comparative weight estimation of sound broadcasting satellites is carried out for various sizes of coverage area and spacecraft antenna, and for different carrier frequencies in the band from 0.5 to 2.0 GHz. It is concluded that relatively light (1200 to about 1500 lbs) spacecraft are feasible, even with low-cost portable or mobile receiving systems.
    Keywords: COMMUNICATIONS AND RADAR
    Type: AIAA PAPER 82-0538 , In: Communications Satellite Systems Conference; Mar 07, 1982 - Mar 11, 1982; San Diego, CA
    Format: text
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  • 10
    Publication Date: 2019-07-13
    Description: This paper is concerned with data pattern sensitivity in carrier tracking performance of an AC coupled Costas loop with a suppressed BPSK signal. The signal amplitude suppression factor is derived as a function of data 'asymmetry ratio' - the ratio of '1's to the total number of bits in a period of a periodic signal. For an asymmetric pattern, the effect of AC coupling is noticeable whereas there is almost no effect for symmetric square wave. The tracking performance with an asymmetric pattern is worse than that with a symmetric pattern. However, it is also shown that as expected, the tracking performance of a DC coupled loop with an asymmetric pattern is better than that with a symmetric pattern.
    Keywords: COMMUNICATIONS AND RADAR
    Type: ITC/USA/''79; Nov 19, 1979 - Nov 21, 1979; San Diego, CA
    Format: text
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