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  • 1
    Electronic Resource
    Electronic Resource
    Calculation of He II flow in tubes (1992)
    Springer
    Journal of low temperature physics 86 (1992), S. 177-211 
    Details
    ISSN: 1573-7357
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Notes: Abstract The flow of superfluid helium through a tube with different temperatures at the ends differs considerably from that of a Newtonian fluid. The strong dependence of the thermodynamic properties on temperature, the internal convection mechanism and the structure of superfluid turbulence causes unusual flows. The equations for the flow of He II are integrated using a new one-dimensional, steady state model to study the flow in a tube. A wide range of driving conditions is studied. The temperature and pressure profiles along the tube fall into four classes. A dimensionless parameter called σ is defined which determines the progression through the four classes of behavior. The deviation of the flow from Newtonian is measured by σ. Significant maxima of the temperature and pressure can occur between the ends of the tube for large values of σ. The shapes of the profiles and the mass flux depend primarily on σ, the geometry and the boundary conditions. Formulas are presented which relate the variables of interest to the boundary conditions. These formulas result from averaging the equations of motion along the tube. A general and unified approach, based on σ, is presented for analyzing experimental data and designing new experiments. It is shown that the common practice of neglecting the pressure term in the energy equation results in poor prediction for many situations. The occurrence of large maxima of pressure and temperature imply that the interpretation of some of the experimental data of the literature should be reconsidered.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01151801
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    Paper (German National Licenses)
    Fulltext
  • 2
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    Infrared Spectrum of the Orion Nebula Between 55 and 200 Microns (1973)
    Institute of Physics
    Details
    Publication Date: 1973-07-01
    Print ISSN: 0004-637X
    Electronic ISSN: 1538-4357
    Topics: Physics
    Published by Institute of Physics
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    PAPER CURRENT
  • 3
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    Infrared spectrum of the Orion Nebula between 55 and 200 microns. (1973)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 183; July 15
    Format: text
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    NASA TECHNICAL REPORTS
  • 4
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    Water vapor absorption spectra of the upper atmosphere /45-185 per cm/ (1975)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: The far IR nighttime absorption spectrum of the earth's atmosphere above 14 km is determined from observations of the bright moon. The spectra were obtained using a Michelson interferometer attached to a 30-cm telescope aboard a high-altitude jet aircraft. Comparison with a single-layer model atmosphere implies a vertical column of 3.4 plus or minus 0.4 microns of precipitable water on 30 August 1971 and 2.4 plus or minus 0.3 microns of precipitable water on 6 January 1972.-
    Keywords: GEOPHYSICS
    Type: Applied Optics; 14; Sept
    Format: text
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    NASA TECHNICAL REPORTS
  • 5
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    Simulation of electronic registration of multispectral remote sensing images to 0.1 pixel accuracy (1984)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: Band-to-band coregistration of multispectral remote sensing images can be achieved by electronic signal processing techniques rather than by costly and difficult mechanical alignment. This paper describes the results of a study of the end-to-end performance of electronic registration. The software simulation includes steps which model the performance of the geometric calibration process, the instrument image quality, detector performance and the effects of achieving coregistration through image resampling. The image resampling step emulates the Pipelined Resampling Processor, a real-time image resampler. The study demonstrates that the electronic alignment technique produces multispectral images which are superior to those produced by an imager whose pixel geometry is accurate to 0.1 pixel rms. The implications of this approach for future earth observation programs are discussed.
    Keywords: EARTH RESOURCES AND REMOTE SENSING
    Format: text
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    NASA TECHNICAL REPORTS
  • 6
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    BASD: SIRTF Telescope Instrument Changeout and Cryogen Replenishment (STICCR) study (1985)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The Space Infrared Telescope Facility (SIRTF) is a long-life cryogenically cooled space-based telescope for infrared astronomy from 2 micrometer to 700 miocrometers currently under study by NASA-ARC, and planned for launch in approximately the mid 90's. SIRTF will operate as a multi-user facility, initially carrying 3 instruments at the focal plane. It will be cooled to below 2 K by superfluid liquid helium to achieve radiometric sensitivity limited only by the statistical fluctuations in the natural infrared background radiation over most of its spectral range. The lifetime of the mission will be limited by the lifetime of the liquid helium supply, and is currently baselined to be 2 years. The telescope changes required to allow in-space replenishment of the 2,000 liter superfluid helium tank are investigated. A preliminary design for the space services equipment is also developed. The impacts of basing the equipment and servicing on the space station are investigated. Space replenishment and changeout of instruments requires changes to the telescope design and preliminary concepts are presented.
    Keywords: SPACECRAFT DESIGN, TESTING AND PERFORMANCE
    Type: NASA-CR-177381 , NAS 1.26:177381 , F85-06
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 7
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    Concepts for on-orbit servicing of SIRTF (1986)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: The usable lifetime of the Space Infrared Telescope Facility (SIRTF) has been assumed to be limited to about two years by the lifetime of the superfluid helium carried in the telescope dewar. Concepts are presented for extending the system life by replenishing the cryogen on orbit, and for replacing the focal plane instruments. The operational aspects and the modifications to the baseline SIRTF are examined. It appears to be feasible to perform these servicing operations based on either the Space Shuttle or on the Space Station.
    Keywords: SPACE TRANSPORTATION
    Format: text
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    NASA TECHNICAL REPORTS
  • 8
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    Flow of superfluid helium in tubes with heated walls (1991)
    In:  Other Sources
    Details
    Publication Date: 2019-08-28
    Description: The equations for superfluid helium flowing through a straight tube with heated walls are integrated. The model equations are based on those of Landau as modified for superfluid turbulence by Gorter and Mellink (1949). The model is implemented by the program SUPERFLOW which runs on a personal computer. The effect of the heating level on the mass flux, the energy flux, and the pressure and temperature profiles is investigated. The four types of profiles which occur without sidewall heating are also found with heated walls. The progression through these four types is shown to depend primarily on the dimensionless parameter, defined previously to characterize the unheated profiles, and a dimensionless ratio of heat fluxes. The pressure and temperature maxima which rise well above the boundary values increase significantly with sidewall heating. Approximate design equations for estimating the mass flux and the profiles are presented. The physical basis of the results is discussed. These results are useful in the design of optimal cooling loops and other superfluid flow systems.
    Keywords: FLUID MECHANICS AND HEAT TRANSFER
    Type: In: Advances in cryogenic engineering. Vol. 37A - Proceedings of the 1991 Cryogenic Engineering Conference, Univ. of Alabama, Huntsville, June 11-14, 1991 (A93-48578 20-37); p. 81-88.
    Format: text
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  • 9
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    System design parameter study for Shuttle Infrared Telescope Facility (SIRTF) (1983)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: SIRTF is a high-sensitivity, cooled astronomical telescope operating from 2 to 1000 microns. The techniques used in analyzing the sensitivity of the SIRTF system performance to several technical issues are presented. Lowering the telescope temperature to near 4K is found to produce margin in several areas. A refined observing requirements model relieves the hardware performance requirements, and identifies extended source size/observing strategy as an important system specification. Other major conclusions are presented.
    Keywords: ASTRONOMY
    Type: Infrared technology IX; Aug 23, 1983 - Aug 25, 1983; San Diego, CA
    Format: text
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    NASA TECHNICAL REPORTS
  • 10
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    Experiments on transferring helium II with a thermomechanical pump (1988)
    In:  Other Sources
    Details
    Publication Date: 2019-07-13
    Description: Porous plugs were tested as thermomechanical pumps for the transfer of helium II from one dewar to another through a transfer line and two valves. SEM images for two different size porous plugs are presented. The present pump design was shown to transfer 80 liters at a maximum flow rate of 90 liters/hr. Temperature, pressure, flow rate, and heater power data are compared with theoretical results.
    Keywords: ENGINEERING (GENERAL)
    Type: Advances in cryogenic engineering.; Jun 14, 1987 - Jun 18, 1987; Saint Charles, IL; United States
    Format: text
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    NASA TECHNICAL REPORTS
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