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  • 1
    ISSN: 1573-9686
    Keywords: Sinusoidal ; CSF ; Cerebrospinal fluid ; System identification
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine , Technology
    Notes: Abstract Cerebrospinal fluid dynamics have been studied in the past by analyses of responses to bolus, constant rate or constant pressure inputs. In this study, we present a method for analyzing CSF pressure responses to sinusoidal variation in the infusion rate. Infusion of artificial CSF into the cisterna magna of adult rats was modulated sinusoidally between 0 and 30 μl/min. The resulting sinusoidal variation in intracranial pressure was recorded on a strip chart recorder simultaneously with the infusion rate signal. The two signals were analyzed for peak-to-peak variation, mean value, and phase shift for input frequencies in the range of 0.0015 to 0.01 Hz (0.00942 to 0.0628 radians/sec). The system was analyzed at each mean infusion rate as a parallel resistance and compliance with a first order linear model. The resistance to CSF outflow was determined as the change in mean steady-state pressure divided by the change in mean infusion rate. The compliance was then obtained from the frequency dependent phase shift between input and output using the first-order linear model. Resistance values were lower for higher average infusion rates consistent with our previous work, while compliance remained constant over the measured pressure range.
    Type of Medium: Electronic Resource
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  • 2
    Publication Date: 2019-06-28
    Description: Studies of the cost and performance of flexible arrays have shown that the most dramatic reductions in the $/Watt figure of merit are achieved by increasing performance. An examination of those properties that contribute to array performance indicated areas where radical changes in current design practice and philosophy would result in significant cost and performance impacts. To take advantage of the predicted cost reductions, modules were fabricated and tested that had ultra-thin superstrates as a load carrying member and large area dielectric wraparound (DWA), gridded back surface and copper contacted solar cells.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Format: text
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  • 3
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    In:  Other Sources
    Publication Date: 2019-07-13
    Description: A system-level approach has been applied in designing a cost-effective 300-1000 kW solar array for Low Earth Orbit (LEO) application with a mission time frame of mid-1980's. Technology investigations and performance and cost prognoses in the area of solar cells and reflector material form a key influence on array design and performance. Major tradeoffs were conducted between planar and concentrator concepts and between silicon and GaAs solar cells. Three baseline design concepts emerged: planar, low-CR concentrator (CR = 5), and high-CR concentrator (CR = 125). Combinations of these concepts with silicon and GaAs solar cells were analyzed in terms of electrical performance, thermal behavior, structural configuration, weight, stowed and deployed volume, and installation/deployment method. To identify the most cost-effective designs, a cost analysis of the candidate arrays was performed. The low-CR/GaAs array and the planar/silicon array demonstrate the greatest cost-effectiveness of the candidate arrays in terms of dollars/watt and energy life-cycle cost. Due to the high uncertainty of GaAs cell-cost prognoses, the sensitivity of the results to the GaAs cell cost is discussed.
    Keywords: SPACECRAFT PROPULSION AND POWER
    Type: Energy to the 21st century; Aug 18, 1980 - Aug 22, 1980; Seattle, WA
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