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  • Other Sources  (378)
  • AIRCRAFT PROPULSION AND POWER  (240)
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  • SPACE RADIATION
  • 1975-1979  (378)
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  • 1976  (378)
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  • 1975-1979  (378)
  • 1960-1964
  • 1930-1934
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  • 1
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    In:  Bull. Seism. Soc. Am., San Francisco, Pergamon, vol. 66, no. 5496, pp. 639-666, pp. B05315, (ISSN: 1340-4202)
    Publication Date: 1976
    Keywords: SModelling ; Source mechanics ; Source ; BSSA
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  • 2
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    In:  Bull. Seism. Soc. Am., San Francisco, Pergamon, vol. 66, no. 6, pp. 1821-1846, pp. 1246
    Publication Date: 1976
    Keywords: Earth tides ; TIDES ; Inhomogeneity ; BSSA
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  • 3
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    In:  Bull. Seism. Soc. Am., Tulsa, 3-4, vol. 66, no. 3-4, pp. 173-187, pp. B09405, (ISBN: 0-12-018847-3)
    Publication Date: 1976
    Keywords: Seismology ; Location ; AUD ; Hypocenter determination ; BSSA
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  • 4
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    In:  Bull. Seism. Soc. Am., Roma, Polish Geothermal Association, vol. 66, no. 2, pp. 1459-1484, pp. B05406, (ISSN: 1340-4202)
    Publication Date: 1976
    Keywords: High frequency ... ; Data analysis / ~ processing ; Fault plane solution, focal mechanism ; Seismology ; BSSA
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  • 5
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    In:  Bulletin of the Seismological Society of America, Tokyo, Am. Geophys. Union, vol. 66, no. 6, pp. 2069-2074, pp. 8043
    Publication Date: 1976
    Keywords: Earthquake precursor: prediction research ; ethics ; Seismology ; society ; BSSA
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  • 6
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    In:  Bull. Seism. Soc. Am., Hannover, Bundesanstalt für Geowissenschaften und Rohstoffe, vol. 66, no. 40, pp. 1441-1457, pp. L08305
    Publication Date: 1976
    Keywords: Nuclear explosion ; Stress ; P-waves ; Seismology ; BSSA
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  • 7
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    In:  Bull. Seism. Soc. Am., London, Geological Society, vol. 66, no. 3, pp. 843-868, pp. L24307, (ISBN 1-86239-117-3)
    Publication Date: 1976
    Keywords: Seismicity ; Turkey ; BSSA
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  • 8
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    In:  Bull. Seism. Soc. Am., Amsterdam, Academic Press (Elsevier), vol. 66, no. 4, pp. 1293-1321, pp. 2486, (ISBN 1-86239-117-3)
    Publication Date: 1976
    Keywords: Site amplification ; Spectrum ; method ; noksp ; BSSA
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  • 9
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    In:  Bull. Seism. Soc. Am., Heidelberg, 1, vol. 66, no. 4-5, pp. 667-675, pp. B01401, (ISBN: 0534351875, 2nd edition)
    Publication Date: 1976
    Keywords: Crustal deformation (cf. Earthquake precursor: deformation or strain) ; Elasticity ; BSSA
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  • 10
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    In:  Bull. Seism. Soc. Am., Regensburg, Inst. Electrical & Electronics Engineers, vol. 66, no. 3, pp. 1501-1523, pp. TC5001, (ISBN: 0534351875, 2nd edition)
    Publication Date: 1976
    Keywords: Source parameters ; Magnitude ; Source ; BSSA
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  • 11
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    In:  Bull. Seism. Soc. Am., Regensburg, Inst. Electrical & Electronics Engineers, vol. 66, no. 3, pp. 1801-1804, pp. TC5001, (ISBN: 0534351875, 2nd edition)
    Publication Date: 1976
    Keywords: Body waves ; Stress drop ; Elasticity ; Seismology ; BSSA
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  • 12
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    In:  Bull. Seism. Soc. Am., Warszawa, Elsevier, vol. 66, no. 1, pp. 617-623, pp. 2091, (ISBN: 0-12-018847-3)
    Publication Date: 1976
    Keywords: Seismology ; BSSA
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  • 13
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    In:  Bull. Seism. Soc. Am., Hannover, FU Berlin, vol. 66, no. 3, pp. 1485-1499, pp. 5091692, (ISBN: 0-12-018847-3)
    Publication Date: 1976
    Keywords: Inversion ; Body waves ; Earthquake ; Source ; Source parameters ; BSSA
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  • 14
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    In:  Bull. Seism. Soc. Am., Houston, Akademie-Verlag, vol. 66, no. 6, pp. 1953-1964, pp. L08310, (ISSN: 1340-4202)
    Publication Date: 1976
    Keywords: Seismology ; Teleseismic events ; Seismic arrays ; Schafer ; BSSA
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  • 15
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    In:  Bull. Seism. Soc. Am., New York, Scientific American, vol. 66, no. Nov., pp. 979-985, pp. B10302, (ISSN: 1340-4202)
    Publication Date: 1976
    Keywords: Seismology ; Instruments ; Detectors ; BSSA
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  • 16
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    In:  Bull. Seism. Soc. Am., Warszawa, EGS, vol. 66, no. 4, pp. 1343-1373, pp. 1089, (ISSN: 1340-4202)
    Publication Date: 1976
    Keywords: Site amplification ; Earthquake engineering, engineering seismology ; Spectrum ; Strong motions ; Magnitude ; Attenuation ; Modelling ; noksp ; BSSA
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  • 17
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    In:  Bull. Seism. Soc. Am., Hannover, Elsevier, vol. 66, no. 4, pp. 1375-1380, pp. L15S14, (ISSN: 1340-4202)
    Publication Date: 1976
    Keywords: Detectors ; Data analysis / ~ processing ; ARRAY ; Seismic networks ; BSSA
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  • 18
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    In:  Bull. Seism. Soc. Am., Corvallis, x + 406 pp., Oregon State University Press, vol. 66, no. 1, pp. 1881-1885, pp. L13610, (ISSN: 1340-4202)
    Publication Date: 1976
    Keywords: EDV ; Energy (of earthquakes) ; Amplitude ; Data analysis / ~ processing ; Reflectivity ; BSSA
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  • 19
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    In:  CASI
    Publication Date: 2006-01-12
    Description: Working primarily from the recent SAS-2 observations of galactic gamma rays, the relation of these observations to the large scale distribution of cosmic rays and interstellar gas in the galaxy is reviewed and reexamined. Starting with a discussion of production rates, the case for pion decay being the predominant production mechanism in the galactic disk above 100 MeV is reestablished and it is also pointed out that Compton gamma rays can be a significant source. To facilitate discussion, the concepts of four distinct galactic regions are defined, viz. the nebulodisk, ectodisk, radiodisk and exodisk. Bremsstrahlung and pion decay gamma rays are associated with the first two (primarily the first) regions, and Compton gamma rays and synchrotron radiation are associated with the latter two regions. On a large scale, the cosmic rays, interstellar gas (primarily H2 clouds in the inner galaxy) and gamma ray emissivity all peak in a region between 5 and 6 kpc from the galactic center. This correlation is related to correlation with other population I phenomena and is discussed in terms of the density wave concept of galactic structure. The singular nature of the HI distribution appears to follow the supernova remnant and pulsar distributions in the galaxy.
    Keywords: SPACE RADIATION
    Type: The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 357-391
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  • 20
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    In:  CASI
    Publication Date: 2006-01-12
    Description: The distribution of nonthermal emissivity with height z above the galactic plane is examined. The main result is that recent observations of the distribution of brightness at intermediate latitudes in the galaxy and of the edge-on spiral galaxy NGC 891 indicate that the emissivity extends to heights of several kpc perpendicular to the plane. The relationship between the nonthermal emissivity and the neutral gas is also studied. In several galaxies the angular distributions of neutral hydrogen and nonthermal emission are roughly coextensive and show similar features such as spiral structure. If radio galaxies and normal galaxies with strong nuclear radio sources are excluded, there appears to be a proportionality between their total HI content and their nonthermal radio luminosity.
    Keywords: SPACE RADIATION
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 206-221
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  • 21
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    In:  CASI
    Publication Date: 2006-01-12
    Description: The detection of gamma rays from supernovae will provide interesting tests of current theory. Some current ideas on the expected gamma ray flux, as modified by recent theoretical results are reviewed.
    Keywords: SPACE RADIATION
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 289-298
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  • 22
    Publication Date: 2006-01-12
    Description: In October 1975 the high energy gamma ray flux from the Vela pulsar was measured by COS-B to be 1.6 to 2.1 times higher than the flux measured by SAS-2 in 1973. The existence is confirmed of a second region of enhanced radiation in the galactic anticenter in addition to that from the Crab pulsar.
    Keywords: SPACE RADIATION
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 45A-51
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  • 23
    Publication Date: 2006-01-12
    Description: Continuing analysis of the data from the SAS-2 high energy gamma-ray experiment has produced an improved picture of the sky at photon energies above 35 MeV. On a large scale, the diffuse emission from the galactic plane is the dominant feature observed by SAS-2. This galactic plane emission is most intense between galactic longitude 310 and 45 deg, corresponding to a region within 7kpc of the galactic center. Within the high-intensity region, SAS-2 observes peaks around galactic longitudes 315 deg, 330 deg, 345 deg, 0 deg, and 35 deg. These peaks appear to be correlated with such galactic features and components as molecular hydrogen, atomic hydrogen, magnetic fields, cosmic ray concentrations, and photon fields.
    Keywords: SPACE RADIATION
    Type: The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 1-11C
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  • 24
    Publication Date: 2006-01-12
    Description: A grazing incidence telescope sensitive to radiation in the 5- to 100-nanometer band was flown in the Apollo service module. On 10 nighttime revolutions, the command and service module was maneuvered to point the instrument at 30 different stellar targets for periods of 1 to 20 minutes, thus constituting the first sensitive search for extreme ultraviolet radiation from nonsolar sources. Several hours of supplementary data were also obtained during nighttime orbits when other experiments in the scientific instrument module bay were operating. Preliminary analysis of a small fraction of the total data indicates the definite detection of a strong source of extreme ultraviolet radiation during observations made during revolution 109. The source is located in Coma Berencies. The suggested optical identification is the white dwarf HZ 43. If this association is correct, the star has the highest temperature of any known white dwarf. Regardless of the optical identification, however, this object is the first nonsolar source to be detected in the extreme ultraviolet band.
    Keywords: SPACE RADIATION
    Type: NASA. Lyndon B. Johnson Space Center Apollo-Soyuz Test Project; 16 p
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  • 25
    Publication Date: 2006-01-12
    Description: The GSFC Cosmic X-ray Spectroscopy experiment aboard OSO-8 has operated successfully since launch providing spectral and temporal data on X-ray sources in tha energy range 2-60 keV. Analysis of quick look data shows a variety of spectral features, some stable, others variable, which will increase understanding of the nature of individual sources. In particular, observed emission and absorption features that can be attributed to iron will result in abundance measures of this important element in sources such as some X-ray binaries, the supernova remnant Cas A, and the nucleus of the galaxy Cen A.
    Keywords: SPACE RADIATION
    Type: X-ray Binaries; p 67-79
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  • 26
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    In:  CASI
    Publication Date: 2006-01-12
    Description: The cosmic rays, an active gaseous component of the disk of the galaxy, are considered along with their propagation and containment as a part of the general dynamics of the disk. The sources of cosmic rays are a matter of speculation. The disk is inflated by the cosmic ray gas pressure comparable to the magnetic pressure, but the rate of inflation is unknown. The time spent by the individual cosmic ray particles in the disk is inversely proportional to the cosmic ray production rate. It is evident from the decay of Be(1c) that the cosmic rays circulate through a volume of space perhaps ten times the thickness of the gaseous disk, suggesting a magnetic halo extending out approximately 1 kpc from either face of the disk. The cosmic rays may be responsible for the halo by inflating the magnetic fields of the disk. Extension of the fields to 1 kpc would imply a high production rate and short life of cosmic rays in the dense gaseous disk of the galaxy.
    Keywords: SPACE RADIATION
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 320-340
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  • 27
    Publication Date: 2006-01-12
    Description: Observation of 0.2-100 MeV diffuse gamma radiation emitted from the Galaxy can provide information on the intensities of 5-50 MeV/nucleon cosmic-rays and 50 MeV electrons in interstellar space. Recent measurements of gamma-rays emitted from the galactic center region provide evidence for a diffuse continuum between 10 and 100 MeV. The intensities of the recently reported nuclear line gamma rays, also observed in the direction of the galactic center, require the presence of intense fluxes of low-energy cosmic-rays in the inner Galaxy if the gamma-rays are produced on a galactic scale. Current detection techniques for 0.1-100 MeV gamma-ray measurements are summarized and their capabilities for measuring the diffuse galactic emission are evaluated.
    Keywords: SPACE RADIATION
    Type: NASA. Goddard Space Flight Center. The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 65-83
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  • 28
    Publication Date: 2006-01-12
    Description: The crystal activation experiment consisted of two sample packages that were flown in the command module and returned to earth for analysis of the radioactivity induced in them during the flight. The objective of the experiment was to define the background caused by detector activation that interferes when gamma radiation is measured in the 0.02- to 10-megaelectronvolt range from earth orbit. Preliminary results show that the activation of the NaI(Tl) crystal was a factor of 3 below that from a similar measurement on Apollo 17. The identification of certain species and the level of activation observed show an important contribution from the interactions of thermal and energetic neutrons produced as secondaries in the spacecraft. That the activation was reduced by only a factor of 3 compared with the Apollo 17 experiment, despite the geomagnetically shielded orbit, possibly indicates more efficient secondary neutron production by the more energetic cosmic rays.
    Keywords: SPACE RADIATION
    Type: Apollo-Soyuz Test Project; 10 p
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  • 29
    Publication Date: 2006-01-12
    Description: Many theoretical models were developed in an attempt to explain the spatial structure in the observed emission which results from interactions of energetic cosmic rays with the interstellar gas. The peaks in the observed distribution are remarkably well correlated with longitudes corresponding to tangential directions to known spiral arm features. Based on theoretical and experimental arguments, it is assumed that on the scale of galactic arms the cosmic rays are more intense where the mass of the gas to which they are coupled is greatest. Refining this model with the results of recent surveys of the interstellar gas, a good fit to the observations is obtained whether the cosmic rays are confined to the spiral arms in the disk or are more evenly confined as in a flat halo model.
    Keywords: SPACE RADIATION
    Type: The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 341-354
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  • 30
    Publication Date: 2006-01-12
    Description: High resolution data on the pulsed gamma ray emission from the Crab and Vela pulsars are presented. The light curves of these two pulsars at gamma ray energies show striking similarities.
    Keywords: SPACE RADIATION
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 52-64
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  • 31
    Publication Date: 2006-01-12
    Description: The COS-B satellite carries a single experiment, capable of detecting gamma rays with energies greater than 30 MeV. Its objectives are to study the spatial, energy, and time characteristics of high energy radiation of galactic and extragalactic origin. The capability to search for gamma ray pulsations is enhanced by the inclusion in the payload of a proportional counter sensitive to X-rays of 2-12 Kev. The experiment was calibrated using particle accelerators. The results of these measurements are presented and the performance of the system in orbit is discussed.
    Keywords: SPACE RADIATION
    Type: NASA. Goddard Space Flight Center The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 23-38
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  • 32
    Publication Date: 2006-01-12
    Description: The Apollo Soyuz Test Project Soft X-ray Experiment was designed to observe celestial X-ray sources in the energy range from 0.1 to 10 kiloelectronvolts. The instrument that was used in the experiment obtained energy and fast timing data to characterize both the spectrum and the variability of known X-ray sources. Data were obtained on approximately 12 sources. During the mission, the instrument developed an intermittent high voltage discharge problem that resulted in the loss of approximately 75 percent of the anticipated data, including the scans intended for mapping of the low energy diffuse X-ray background.
    Keywords: SPACE RADIATION
    Type: NASA. Lyndon B. Johnson Space Center Apollo-Soyuz Test Project; 11 p
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  • 33
    Publication Date: 2006-01-12
    Description: Gamma-ray emission was detected from the radio pulsars PSR1818-04 and PSR1747-46, in addition to the previously reported gamma-ray emission from the Crab and Vela pulsars. Since the Crab pulsar is the only one observed in the optical and X-ray bands, these gamma-ray observations suggest a uniquely gamma-ray phenomenon occurring in a fraction of the radio pulsars. Using distance estimates it is found that PSR1818-04 has a gamma-ray luminosity comparable to that of the Crab pulsar, while the luminosities of PSR1747-46 and the Vela pulsar are approximately an order of magnitude lower. This survey of SAS-2 data for pulsar correlations has also yielded upper limits to gamma-ray luminosity for 71 other radio pulsars.
    Keywords: SPACE RADIATION
    Type: The Struct. and Content of the Galaxy and Galactic Gamma Rays; p 12-22
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  • 34
    Publication Date: 2006-01-12
    Description: During the first months of operation, COS-B has observed galactic high energy gamma rays from the galactic disc. In the galactic center and Vela regions the disc emission distribution was measured. From these data the existence of a local ( 1 kpc) and a distant ( 3 kpc) emitting region is apparent in the general direction of the inner galaxy.
    Keywords: SPACE RADIATION
    Type: NASA. Goddard Space Flight Center The Galaxy and Galactic Gamma Rays; p 39-44
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  • 35
    Publication Date: 2006-01-12
    Description: The Apollo Soyuz Test Project Interstellar Helium Glow Experiment (MA-088) studied the motion of helium in the local interstellar medium as that medium passed through the solar system to determine several poorly known properties of the local interstellar gas. The instrument used was a photometer sensitive to two solar extreme ultraviolet spectral lines that are resonantly scattered by helium gas. The instrument surveyed the entire celestial sphere during a series of slow, rolling maneuvers by the Apollo spacecraft. The equipment operated properly, and usable data were obtained.
    Keywords: SPACE RADIATION
    Type: NASA. Lyndon B. Johnson Space Center Apollo-Soyuz Test Project; 15 p
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  • 36
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    Publication Date: 2011-08-17
    Description: Jupiter's decimetric emission is universally identified as synchrotron radiation from about 10 MeV electrons. These electrons radiate away their energy in a few months and hence must be continuously replaced. A theory in which electrons are injected at Jupiter's magnetopause and radially diffuse toward the planetary surface, gaining energy in the process is summarized. The radial diffusion coefficient in the inner magnetosphere is determined. This diffusion coefficient, which also holds for protons, is sufficiently small that the inner Galilean satellites can wipe out large fractions of the incoming proton and electron fluxes. The reduction of the proton flux is extremely important to the survival of the Pioneer experimental payloads.
    Keywords: SPACE RADIATION
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  • 37
    Publication Date: 2011-08-17
    Description: A candidate hodoscope uses arrays of scintillator fibers, followed by an image intensifier and imaging system such as that proposed for the X-ray shadowgraph. A literature search was performed to ascertain the experience of other workers with hodoscopes using this or similar principles. Calculations were performed to determine the feasibility of candidate systems and some laboratory experiments were performed to attempt to check these numbers.
    Keywords: SPACE RADIATION
    Type: The Specific Light Output of Cesium Iodide Crystals; p 45-58
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  • 38
    Publication Date: 2011-08-16
    Description: A study of the gas-to-dust ratio suggests that interstellar reddening may provide an accurate way of assessing column densities in various directions in the Galaxy. A gamma ray intensity of 7.25 x 10 to the -5th E sub B-V photon/sq cm/s/sterad is predicted for regions of the Galaxy where the medium cosmic ray density is equal to that observed close to the sun. It is found that in the longitude range of about 0-180 degrees, the large scale cosmic ray distribution producing the gamma rays follows that of extreme population I stars put in evidence by giant H II regions, and that of molecular hydrogen traced by carbon monoxide emission. The gamma-ray production exhibits a maximum at R roughly equal to 5 kpc, and practically vanishes at R not less than 11 kpc, beyond the location of the outermost H II regions.
    Keywords: SPACE RADIATION
    Type: Astronomy and Astrophysics; 50; 2, Ju; July 197
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  • 39
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    Publication Date: 2011-08-17
    Description: The paper considers the consistency of positrons and electrons with a propagation model in which the cosmic rays are stopped by nuclear collisions or energy losses before they can escape from the Galaxy (the closed-galaxy model). The fact that no inconsistency is found between the predictions and the data implies that the protons which produce the positrons by nuclear reactions could have their origin in a large number of distant sources, as opposed to the heavier nuclei which in this model come from a more limited set of sources. The closed-galaxy model predicts steep electron and positron spectra at high energies. None of these are inconsistent with present measurements; but future measurements of the spectrum of high-energy positrons could provide a definite test for the model. The closed-galaxy model also predicts that the interstellar electron intensity below a few GeV is larger than that implied by other models. The consequence of this result is that electron bremsstrahlung is responsible for about 50% of the galactic gamma-ray emission at photon energies greater than 100 MeV
    Keywords: SPACE RADIATION
    Type: Astrophysics and Space Science; 45; Nov. 197
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  • 40
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    Publication Date: 2011-08-17
    Description: High resolution measurement of the iron group nuclei was performed with the intention of determining individual abundances in the cosmic ray flux at the earth of particles with z = 22 to 30. Of the three types of dE/dx detectors used in the experiment, pulse ion chambers, Cerenkov radiators and scintillators, the first has the best z resolution over a wide range of particle z and energy. The plastic scintillators define the particle acceptance cone of the telescope while the Cerenkov detector aids in rejection of low energy particle background and measurement of particle velocity.
    Keywords: SPACE RADIATION
    Type: The Specific Light Output of Cesium Iodide Crystals; p 1-44
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  • 41
    Publication Date: 2011-08-16
    Description: The intensity and energy spectrum of primary cosmic electrons from 10 to about 250 GeV have been studied by using balloon-borne detectors. The detectors were large-area ionization calorimeters which sampled showering particles frequently and demonstrated an energy resolution of about 7% in calibration tests. On one of the flights a time-of-flight system and detectors to sample the lateral properties of showers were used to examine and to test background rejection. The results of the balloon flights from Alamogordo, N. Mex., in 1970 and Cape Girardeau, Mo., in 1972 indicated that the primary cosmic ray electron differential energy spectrum exhibits no change of slope in the energy range measured and is well represented by a power law. The results indicate that the cosmic electron spectrum is steeper than the cosmic ray proton spectrum. It is shown that these data are consistent with the leakage lifetime model for the propagation of cosmic electrons in the galaxy, although other more complex models cannot be excluded on the basis of these data.
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 81; Aug. 1
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  • 42
    Publication Date: 2011-08-16
    Description: The current theory of solar modulation can be used to argue that the cosmic-ray component at low energies, which is observed to have an anomalous composition, is not of galactic origin, i.e., it is not a component of the galactic cosmic-ray flux. The current theory predicts, from quite general considerations, that an unreasonably large intensity of cosmic rays, by many orders of magnitude, would be required in the interstellar medium to account for the observed fluxes. Conceivably, the current modulation theory could be modified so that only reasonable interstellar fluxes are predicted. One such modification involves an unusual scheme for particle diffusion in the interplanetary medium. Particles are assumed to diffuse not as a result of their own motion among small-scale irregularities in the magnetic field, but rather in a process in which they are trapped between time-varying constrictions in the large-scale field.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 206; May 15
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  • 43
    Publication Date: 2011-08-16
    Description: Results are presented for detailed Monte Carlo calculations of the interaction histories of ultrahigh-energy cosmic-ray nuclei with intergalactic radiation fields, using improved estimates of these fields and empirical determinations of photonuclear cross sections, including multinuclear disintegrations for nuclei up to Fe-56. Intergalactic and galactic energy-loss rates and nucleon-loss rates for nuclei up to Fe-56 are also given. Astrophysical implications are discussed in terms of expected features in the cosmic-ray spectrum between 10 to the 18th and 10 to the 21st power eV for the universal and supercluster origin hypotheses. The results of these calculations indicate that ultrahigh-energy cosmic rays cannot be universal in origin regardless of whether they are protons or nuclei. Both the supercluster and galactic origin hypotheses, however, are possible regardless of nuclear composition.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 205; Apr. 15
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  • 44
    Publication Date: 2011-08-16
    Description: Cosmic rays interact with mesoscale configurations of the interplanetary magnetic field. A technique is presented for calculating such configurations in the inner solar system, which are due to streams and source conditions near the sun, and maps of magnetic field are constructed for some plausible stream and source conditions. One effect of these mesoscale configurations on galactic cosmic rays is shown to be an out-of-the-ecliptic gradient drift sufficient to explain Forbush decreases. The effects on solar energetic particles include small polar drifts due to the field gradients and a possibly large modification of the time-intensity profiles and anisotropy characteristics due to the formation of mirror configurations in space. If a diffusion model is applicable to solar particles, the true diffusion coefficient will be masked by the effects of streams. A conceptual model which incorporates these ideas and those of several other models is presented.
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 81; May 1
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  • 45
    Publication Date: 2011-08-16
    Description: Corotating proton and electron streams are the dominant type of low-energy (i.e., 0.1-10 MeV per nucleon) particle event observed at 1 AU. The radial dependence of these events has been studied between 1 and 4 AU using essentially identical low-energy detector systems on IMP-7, Pioneer-10, and Pioneer-11. It had been expected that at a given energy, the intensity of these streams would decrease rapidly with heliocentric distance due to the effects of interplanetary adiabatic deceleration. Instead, it is observed that from event to event, the intensity either remains roughly constant or increases significantly (more than an order of magnitude) between 1 and 4 AU. It appears that interplanetary acceleration processes are the most plausible explanation. Several possible acceleration models are discussed.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 203; Feb. 1
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  • 46
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    Publication Date: 2011-08-17
    Description: Arrays of fibers made of scintillating material were used as position-sensitive detectors or hodoscopes for beam-finding at ion accelerators. Experiments were made with alpha's from an Am241 source incident upon one end of the fiber, the other end being viewed with a photomultiplier tube. The scintillation light was not detected in any of the fibers tested beyond about 5 cm. The effective useful lengths for detection of relativistic heavy ions were given.
    Keywords: SPACE RADIATION
    Type: The Specific Light Output of Cesium Iodide Crystals; p 59-63
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  • 47
    Publication Date: 2011-08-16
    Description: The paper examines the medium-energy (about 10-30 MeV) galactic gamma-ray radiation from primary and secondary electrons and calculates the expected gamma-ray distribution for the specific model of Bignami et al. (1975) on the assumption that the cosmic rays are correlated with the matter on the scale of galactic arms. The energy spectrum typical of regions near the galactic center indicates a dramatic shift from a predominantly cosmic-ray nucleonic mechanism at higher energies to a cosmic-ray electron mechanism at the lower energies. This provides a most important and direct means of probing the cosmic-ray electrons as a function of galactic position by making gamma-ray observations in the few to 40 MeV energy range. Medium-energy gamma-ray astronomy is shown to be a valuable tool in galactic research.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 208; Aug. 15
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  • 48
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    In:  Other Sources
    Publication Date: 2011-08-16
    Description: The papers in this volume deal essentially with the question whether the amplification of noise is due to the jet noise phenomenon or perhaps an interaction of airframe and core engine noise. In the area of jet noise suppression, various promising suppressor concepts are examined. The swirling flow jet noise suppressor is shown to provide significant noise reduction with minimal thrust losses. Progress in the aircraft engine core noise problem is reflected by seven research-type papers. Two possible mechanisms are seen to be responsible for core noise. One is the direct noise radiated from the turbulent combustion in the primary combuster and transmitted through the turbine, passing out the nozzle into the far field. The other mechanism is the noise that is emitted from hot spots being convected through the turbine. Which of these mechanisms (or perhaps both mechanisms) is responsible for core noise, and what are the coupling mechanisms of core engine noise and jet noise are the questions confronting researchers.
    Keywords: AIRCRAFT PROPULSION AND POWER
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  • 49
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    Publication Date: 2011-08-16
    Description: The paper reviews the current status of observational research into the highly puzzling problem of cosmic gamma-ray bursts. Up to now there is no convincing temporal or spatial correlation with any known celestial processes or objects. The typical burst source strength is somewhere between 10 to the 26th power ergs and 10 to the 52nd power ergs. A list of 39 confirmed and 9 unconfirmed cosmic gamma-ray bursts observed by satellite is given, showing times of occurrence and in some cases, the size in erg per square centimeter. Several approaches to the problem of source object identification are discussed: (1) accumulation of observation statistics with their present poor resolution and research for correlative phenomena, (2) mapping out celestial source distributions with moderate resolution in order to search for galactic or other anisotropies in direction or to look for repeating source regions, and (3) very high-accuracy localization of the source directions of one or several bursts in order to pinpoint a tiny fraction of the celestial sphere for correlative radio, optical and X-ray studies. Planned future instrumentation for deep space probes and multiple-balloon studies is described.
    Keywords: SPACE RADIATION
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  • 50
    Publication Date: 2011-08-16
    Description: A plasma strong turbulence, weak coupling, theory is applied to the problem of cosmic-ray pitch-angle scattering in magnetostatic turbulence. The theory used is a rigorous generalization of Weinstock's 'resonance broadening' theory and contains no ad hoc approximations. A detailed calculation is presented for a model of 'slab' turbulence with an exponential correlation function. The results agree well with numerical simulations. The rigidity dependence of the pitch-angle scattering coefficient differs from that found by previous researchers. The differences result from an inadequate treatment of particle trajectories near 90 deg pitch angle in earlier work.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 204; Mar. 15
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  • 51
    Publication Date: 2011-08-16
    Description: The flux density of cosmic-ray positrons and electrons was measured by a balloon-borne spark chamber magnetic spectrometer in two flights in an attempt to study the solar modulation of galactic cosmic rays. The total electron flux was found to be about 0.03/cu m/s/sr/MeV between 70 and 800 MeV and to increase toward lower energies, while the positron flux decreased sharply toward lower energies from about 0.008/cu m/s/sr/MeV at 650 MeV and only upper limits were obtained for positrons below 200 MeV. At energies above 180 MeV, the spherically symmetrical Fokker-Planck equation with a diffusion coefficient proportional to the particle rigidity provided a reasonable fit to both positron and total electron data, while at energies below 180 MeV, the data were consistent with a continuation of the same diffusion coefficient and local source of electrons, or a change in the diffusion coefficient to a constant value.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 204; Mar. 15
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  • 52
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    Publication Date: 2011-08-16
    Description: The indirect method of estimating the diffuse metagalactic flux of ionizing radiation proposed by Sunyaev (1969) is reconsidered in the light of further studies of the interaction of this radiation with galactic gas. An upper limit is derived for the intensity of the metagalactic background radiation to which the neutral interstellar medium is exposed. This limit on the ionizing radiation flux severely restricts the emission from a galactic corona containing gas in the temperature range 100,000 to 1,000,000 K. An upper limit of 10 to the 29.2 erg/sec/Hz is obtained for the mean luminosity radiated by a quasar in the energy band 40-170 eV. The 21-cm observations examined indicate that further than about 30 kpc from the center of the galaxy self-shielding by H II is possible only when the critical metagalactic ionizing flux is not exceeded.
    Keywords: SPACE RADIATION
    Type: Nature; 260; Apr. 8
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  • 53
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    In:  CASI
    Publication Date: 2016-06-07
    Keywords: SPACE RADIATION
    Type: Lunar Science Inst., Abstracts of Papers Presented at a Special Session of the Seventh Annual Lunar Science Conference on Utilization of Lunar Materials and Expertise for Large Scale Operations in Space; p 81-86
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  • 54
    Publication Date: 2017-10-02
    Description: The effects of afterburner light-off and shut-down transients on the compressor stability are investigated. The reported experimental results are based on detailed high response pressure and temperature measurements on the TF30-P-3 turbofan engine. The tests were performed in an altitude test chamber simulating high altitude engine operation. It is shown that during both types of transients, flow breaks down in the forward part of the fan bypass duct. At a sufficiently low engine inlet pressure this resulted in a compressor stall. Complete flow breakdown within the compressor was preceded by a rotating stall. At some locations in the compressor, rotating stall cells initially extended only through part of the blade span. For the shutdown transient the time between first and last detected occurrence of rotating stall is related to the flow Reynolds number. An attempt was made to deduce the number and speed of propagation of rotating stall cells.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AGARD Unsteady Phenomena in Turbomachinery; 12 p
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  • 55
    Publication Date: 2017-10-02
    Description: Propulsion systems are evaluated in terms of relative aircraft range for a fixed payload and takeoff gross weight with a design cruise Mach number of 2.7. In order to put the performance of these engines in perspective, a comparison of these engines and the former U.S. SST engine is made with an idealized variable cycle engine whose performance at all operating points matches that of an optimized point design cycle within specified limits. Range comparisons are made with and without noise level constraints to determine the influence of noise upon cycle selection. The critical areas requiring new or improved technology for each cycle are delineated.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AGARD Variable Geometry and Multicycle Eng.; 19 p
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  • 56
    Publication Date: 2016-06-07
    Description: The status of the Federal Aviation Administration's High Altitude Pollution Program is described which was instituted to develop the detailed quantitative information needed to judge whether or not regulatory action to limit such exhaust emissions would be necessary. The complexities of this question and the nature and magnitude of uncertainties still present in our scientific understanding of the potential interactions between aircraft exhaust emissions and stratospheric ozone and climate are reviewed. The direction and scope of future Federal and international activities are described.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Langley Res. Center Proc. of the SCAR Conf., Pt. 2,; 10 p
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  • 57
    Publication Date: 2016-06-07
    Description: Various experiments are sponsored and conducted by NASA to explore the potential of advanced combustion techniques for controlling aircraft engine emissions into the upper atmosphere. Of particular concern are the oxide of nitrogen (NOx) emissions into the stratosphere. The experiments utilize a wide variety of approaches varying from advanced combustor concepts to fundamental flame tube experiments. Results are presented which indicate that substantial reductions in cruise NOx emissions should be achievable in future aircraft engines. A major NASA program is described which focuses the many fundamental experiments into a planned evolution and demonstration of the prevaporized-premixed combustion technique in a full-scale engine.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Proc. of the SCAR Conf., Pt. 2,; 22 p
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  • 58
    Publication Date: 2016-06-07
    Description: Two engine components, fan blades and exhaust systems, were selected for composite materials development efforts in support of the supersonic cruise aircraft research (SCAR) engine program. The materials selected were boron/aluminum for fan blades and silicon carbide/superalloy sheet for the exhaust system. The current status of the research into applying these two composite materials to SCAR engines is reviewed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Proc. of the SCAR Conf., Part 1; p 457-468
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  • 59
    Publication Date: 2016-06-07
    Description: The objectives and status of the propulsion program, along with the results acquired in the various technology areas, are discussed. The instrumentation requirements for and experience with flight testing the propulsion systems at high supersonic cruise are reported. Propulsion system performance differences between wind tunnel and flight are given. The effects of high frequency flow fluctuations (transients) on the stability of the propulsion system are described, and shock position control is evaluated.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Proc. of the SCAR Conf., Part 1; p 417-456
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  • 60
    Publication Date: 2016-06-07
    Description: The propulsion control requirements of supersonic aircraft are presented. Integration of inlet, engine, and airframe controls is discussed. The application of recent control theory developments to propulsion control design is described. Control component designs for achieving reliable, responsive propulsion control are also discussed.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Proc. of the SCAR Conf., Part 1; p 399-415
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  • 61
    Publication Date: 2016-06-07
    Description: The performance of candidate supersonic cruise inlets is reviewed and the aerodynamic installation penalties for each type are defined. The main characteristics that affect the airflow schedules of variable cycle engines are defined. These schedules are compared with the airflow schedules of the candidate inlets, and appropriate inlets are matched to the variable-cycle engine characteristics. Auxiliary inlets are also considered.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Proc. of the SCAR Conf., Part 1; p 387-397
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  • 62
    Publication Date: 2016-06-07
    Description: The Variable Stream Control Engine is studied for advanced supersonic cruise aircraft. Significant environmental and performance improvements relative to first generation supersonic turbojet engines are cited. Two separate flow streams, each with independent burner and nozzle systems are incorporated within the engine. By unique control of the exhaust temperatures and velocities in two coannular streams, significant reduction in jet noise is obtained.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Langley Res. Center Proc. of the SCAR Conf., Part 1; p 341-352
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  • 63
    Publication Date: 2016-06-07
    Description: Sustained supersonic cruise propulsion systems for military applications are studied. The J79-5 in the Mach 2 B-58; YJ93 in the Mach 3.0 B-70 and the current F101 in the B-1, are all examples of military propulsion systems and airplanes operated at sustained supersonic cruise speeds. The Mach 2.7 B2707 transport powered by GE4 turbojet engines was the only non-military, sustained supersonic cruise vehicle intended for commercial passenger service.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA Proc. of the SCAR Conf., Part 1; p 353-370
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  • 64
    Publication Date: 2016-06-07
    Description: Variable cycle engine (VCE) concepts for a supersonic cruise aircraft were studied. These VCE concepts incorporate unique critical components and flow path arrangements that provide good performance at both supersonic and subsonic cruise and appear to be economically and environmentally viable. Certain technologies were identified as critical to the successful development of these engine concepts and require considerable development and testing. The feasibility and readiness of the most critical VCE technologies, was assessed, a VCE component test program was initiated. The variable stream control engine (VSCE) component test program, tested and evaluated an efficient low emission duct burner and a quiet coannular ejector nozzle at the rear of a rematched F100 engine.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Proc. of the SCAR Conf., Part 1; p 371-385
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  • 65
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    Publication Date: 2016-06-07
    Description: The exhaust emission test was designed to measure hydrocarbons, carbon monoxide, and oxides of nitrogen concentrations and determine mass emissions through calculations during a simulated aircraft landing-takeoff cycle. The calculations required to convert exhaust emission concentrations (raw emission measurements) into mass emissions were emphasized.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 357-378
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  • 66
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    Publication Date: 2016-06-07
    Description: Good instrumentation was required to obtain reliable and repeatable baseline data. Problems that were encountered in developing such a total system were: (1) accurate airflow measurement, (2) precise fuel flow measurement, and (3) the instrumentation used for pollutant measurement was susceptible to frequent malfunctions. Span gas quality had a significant effect on emissions test results. The Spindt method was used in the piston aircraft emissions program. The Spindt method provided a comparative computational procedure for fuel/air ratio based on measured emissions concentrations.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 337-356
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  • 67
    Publication Date: 2016-06-07
    Description: The General Aviation Manufacturers recommended that the EPA rescind the aircraft piston engine emissions regulations currently on the books. The reason was the very small emission reduction potential and the very poor benefit-cost ratio involved in this form of emission reduction. The limited resources of this industry can far better be devoted to items of much greater benefit to the citizens of this country - reducing noise, improving fuel efficiency (which will incidently reduce exhaust emissions), and improving the safety, operational, and economic aspects of aircraft, all far greater contributions to our total national transportation system.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 329-336
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  • 68
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    In:  CASI
    Publication Date: 2016-06-07
    Description: The most promising alternative engine (or engines) for application to general aircraft in the post-1985 time period was defined, and the level of technology was cited to the point where confident development of a new engine can begin early in the 1980's. Low emissions, multifuel capability, and fuel economy were emphasized. Six alternative propulsion concepts were considered to be viable candidates for future general-aircraft application: the advanced spark-ignition piston, rotary combustion, two- and four-stroke diesel, Stirling, and gas turbine engines.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aircraft Piston Eng. Exhaust Emissions Symp.; p 315-328
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  • 69
    Publication Date: 2016-06-07
    Description: A long-range technology plan in support of general aviation engines was formulated and is being implemented at the Lewis Research Center. The overall program was described, and that part of the program that represents the in-house effort at Lewis was presented in detail. Three areas of government and industry effort involving conventional general-aviation piston engines were part of a coordinated overall plan: (1) FAA/NASA joint program, (2) NASA contract exhaust emissions pollution reduction program, and (3) NASA in-house emissions reduction and new technology program.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aircraft Piston Eng. Exhaust Emissions Symp.; p 295-314
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  • 70
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    In:  CASI
    Publication Date: 2016-06-07
    Description: The emission problem or source points were defined and new materials, hardware, or operational procedures were developed to exercise the trends defined by the data collected. The programs to reduce the emission output of aircraft powerplants were listed. Continued establishment of baseline emissions for various engine models, continued characterization of effect of production tolerances on emissions, carbureted engine development and flight tests, and cylinder cooling/fin design programs were several of the programs investigated.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 283-294
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  • 71
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    Publication Date: 2016-06-07
    Description: The standards promulgated by the Environmental Protection Agency (EPA) for carbon monoxide (CO), unburned hydrocarbon (HC), and oxides-of-nitrogen (NOx) emissions were the basis in a study of ways to reduce emissions from aircraft piston engines. A variable valve timing system, ultrasonic fuel atomization, and ignition system changes were postulated.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 255-274
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  • 72
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    Publication Date: 2016-06-07
    Description: The NASA Lewis Research Center issued requests for proposal to Avco Lycoming and Teledyne Continental Motors for a contractual effort to establish and demonstrate engine modifications to reduce exhaust emissions safely with minimum adverse effects on cost, weight, and fuel economy. The secondary objective was reducing fuel consumption.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aircraft Piston Eng. Exhaust Emissions Symp.; p 225-226
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  • 73
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    Publication Date: 2016-06-07
    Description: A company program was planned which has a main drive to develop those emission reduction concepts that have the promise of earliest success. These programs were proposed in an attempt to enhance existing engine systems, exploiting their potential for emission reduction as far as is compatible with retaining the well established features in them that are well understood and in current production. The intended programs identified in the area of new concepts were: (1) upgrading the TCM fuel system, (2) evaluation of accelerator pump, (3) reduced cooling requirement, and (4) variable spark timing.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 275-282
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  • 74
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    In:  CASI
    Publication Date: 2016-06-07
    Description: Two different aircraft designs, each with two modified fuel control systems, were evaluated. Each aircraft was evaluated in a given series of defined ground and flight conditions while quantitative and qualitative observations were made. During this program, some ten flights were completed, and a total of about 13 hours of engine run time was accumulated by the two airplanes. The results of these evaluations with emphasis on the operational and safety aspects were analyzed. Ground tests of the engine alone were not able to predict acceptable limiting lean mixture settings for the flight envelopes of the Cessna Models 150 and T337.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 209-224
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  • 75
    Publication Date: 2016-06-07
    Description: Five different engine models were tested covering combinations of all engine categories in current production in the range from 100 to 435 brake horsepower. Engines were divided into five major types: carbureted, fuel injected, direct drive, geared, and turbocharged. Emissions data were categorized by three separate fuel system schedules: baseline, case 1, and case 2. Baseline was defined as the average fuel flow rate established by the fuel system's production tolerance band when operated with the mixture control at the full-rich position. Case 1 was defined as the minimum allowable fuel flow rate established by the engine certification. Case 2 was defined as the fuel rate corresponding to the leanest fuel-air ratio obtainable before a safety limit occurred with the engine operating on a propeller test stand. Safety limits that developed during testing were cylinder-head overheating or inadequate acceleration from a given mode of operation.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 179-208
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  • 76
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    In:  CASI
    Publication Date: 2016-06-07
    Description: The Avco Lycoming flight test program for reduced emissions was conducted to determine and document the lean fuel schedule limits for current production aircraft based on flight safety. Based on analysis of the emissions profile, Avco Lycoming proposed to evaluate the effect of leaner schedules in the idle/taxi, climb, and approach modes. These modes were selected as areas where it was felt that possible improvements could be made with the greatest improvement in cyclic emissions reduction. The fuel systems to produce these leaner stepped fuel schedules were tailored specifically for the flight test.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 141-178
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  • 77
    Publication Date: 2016-06-07
    Description: Exhaust gas pollutant emissions data under test stand conditions were obtained for the following: (1) full-rich baseline test (7-mode cycle), (2) lean-out tests for each power mode, and (3) different spark settings. The test data were also used to create a theoretical 5-mode cycle baseline. The emissions data in the framework of the theoretical 5-mode cycle were emphasized. There is no significant difference in the test results produced by data exhibited on the 7-mode cycle or 5-mode cycle. The 5-mode cycle was slightly more conservative for the carbon monoxide pollutant than the 7-mode cycle. The data were evaluated to determine which mode(s) had the greatest influence on improving general aviation piston engine emissions. Improvements that were achieved as a result of making lean-out adjustments to the fuel metering device were: (1) taxi mode only, (2) taxi and approach modes combined, and (3) leaning-out of the climb mode to best power.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 121-140
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  • 78
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    Publication Date: 2016-06-07
    Description: The computational procedures that are involved in exhaust emissions data reduction and the use of these computational procedures for determining the quality of the data that is obtained from exhaust measurements were considered. Four problem areas were calculated: (1) the various methods for performing the carbon balance, (2) the method for calculating water correction factors, (3) the method for calculating the exhaust molecular weight, and (4) assessing the quality of the data.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 73-84
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  • 79
    Publication Date: 2016-06-07
    Description: The importance of measuring accurate air and fuel flows as well as the importance of obtaining accurate exhaust pollutant measurements were emphasized. Some of the problems and the corrective actions taken to incorporate fixes and/or modifications were identified.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 45-72
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  • 80
    Publication Date: 2016-06-07
    Description: Five different engine models were tested to experimentally characterize emissions and to determine the effects of variation in fuel-air ratio and spark timing on emissions levels and other operating characteristics such as cooling, misfiring, roughness, power acceleration, etc. The results are given of two NASA reports covering the Avco Lycoming 0-320-D engine testing and the recently obtained results on the Teledyne Continental TSIO-360-C engine.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Aircraft Piston Eng. Exhaust Emissions Symp.; p 85-120
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  • 81
    Publication Date: 2016-06-07
    Description: The possibility was evaluated for achieving the EPA Standards for HC and CO emissions through the use of air-fuel ratio enleanment at selected power modes combined with improved air-fuel mixture preparation, and in some cases improved cooling. Air injection was also an effective approach for the reduction of HC and CO, particularly when combined with exhaust heat conservation techniques such as exhaust port liners.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 23-44
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  • 82
    Publication Date: 2016-06-07
    Description: Piston engine light aircraft are significant sources of carbon monoxide in the vicinity of high activity general aviation airports. Substantial reductions in carbon monoxide were achieved by fuel mixture leaning using improved fuel management systems. The air quality impact of the hydrocarbon and oxides of nitrogen emissions from piston engine light aircraft were insufficient to justify the design constraints being confronted in present control system developments.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA. Lewis Res. Center Aircraft Piston Eng. Exhaust Emissions Symp.; p 1-22
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  • 83
    Publication Date: 2016-06-07
    Description: Combustion research related to hypersonic scramjet (supersonic combustion ramjet) propulsion is discussed from the analytical point of view. Because the fuel is gaseous hydrogen, mixing is single phase and the chemical kinetics are well known; therefore, the potential for analysis is good relative to hydro-carbon fueled engines. Recent progress in applying two and three dimensional analytical techniques to mixing and reacting flows indicates cause for optimism, and identifies several areas for continuing effort.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Advan. in Eng. Sci., Vol. 4; p 1629-1639
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  • 84
    Publication Date: 2016-06-07
    Description: A digitally implemented integrated inlet/engine control system was developed and tested on a mixed compression, Mach 2.5, supersonic inlet and augmented turbofan engine. The control matched engine airflow to available inlet airflow so that in steady state, the shock would be at the desired location, and the overboard bypass doors would be closed. During engine induced transients, such as augmentor lights and cutoffs, the inlet operating point was momentarily changed to a more supercritical point to minimize unstarts. The digital control also provided automatic inlet restart.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: Advanced Control Technol. and its Potential for Future Transport Aircraft; p 503-524
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  • 85
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2016-06-07
    Description: A brief critique of spherically symmetric conventional modulation theory is supplied. Estimates are made of the cosmic ray intensity at high solar latitudes. Direct evidence for significant off-ecliptic cosmic ray gradients is reviewed in support of the requirement for an off-ecliptic spacecraft mission. The possibility of measuring the galactic spectrum is discussed. The effect of interplanetary magnetic fields on cosmic ray motion is examined, and calculations (Fokker-Planck equation) are shown.
    Keywords: SPACE RADIATION
    Type: NASA. Goddard Space Flight Center Proc. of the Symp. on the Study of the Sun and Interplanetary Medium in Three Dimensions; p 210-230
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  • 86
    Publication Date: 2017-10-02
    Description: Single stage fans designed for two levels of pressure ratio or blade loading were subjected to screen induced circumferential distortions of 90 degree extent. Both fan rotors were designed for a blade tip speed of 425 m/sec, blade solidity of 1.3 and a hub-to-tip radius ratio of 0.5. Circumferential measurements of total pressure, temperature, static pressure, and flow angle were obtained at the hub, mean and tip radii at five axial stations. Rotor loading level did not appear to have a significant influence on rotor response to distorted flow. Losses in overall pressure ratio due to distortion were most severe in the stator hub region of the more highly loaded stage. At the near stall operating condition tip and hub regions of (either) rotor demonstrated different response characteristics to the distorted flow. No effect of loading was apparent on interactions between rotor and upstream distorted flow fields.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: AGARD Unsteady Phenomena in Turbomachinery; 26 p
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  • 87
    Publication Date: 2019-06-27
    Description: A variable pitch fan actuation system was designed which incorporates a remote nacelle-mounted blade angle regulator. The regulator drives a rotating fan-mounted mechanical actuator through a flexible shaft and differential gear train. The actuator incorporates a high ratio harmonic drive attached to a multitrack spherical cam which changes blade pitch through individual cam follower arms attached to each blade trunnion. Detail design parameters of the actuation system are presented. These include the following: design philosophies, operating limits, mechanical, hydraulic and thermal characteristics, mechanical efficiencies, materials, weights, lubrication, stress analyses, reliability and failure analyses.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134852 , HSER-7001
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  • 88
    Publication Date: 2019-06-27
    Description: The mechanical design of the boiler plate nacelle and core exhaust nozzle for the QCSEE under the wing engine is presented. The nacelle, which features interchangeable hard-wall and acoustic panels, is to be utilized in the initial engine testing to establish acoustic requirements for the subsequent composite nacelle as well as in the QCSEE over the wing engine configuration.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135008 , R76AEG222
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  • 89
    Publication Date: 2019-06-27
    Description: The preliminary design and installation of high bypass, geared turbofan engine with a composite nacelle forming the propulsion system for a short haul passenger aircraft are described. The technology required for externally blown flap aircraft with under the wing (UTW) propulsion system installations for introduction into passenger service in the mid 1980's is included. The design, fabrication, and testing of this UTW experimental engine containing the required technology items for low noise, fuel economy, with composite structure for reduced weight and digital engine control are provided.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134868 , R75AEG349
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  • 90
    Publication Date: 2019-06-27
    Description: The aerodynamic and mechanical design of a fixed-pitch 1.36 pressure ratio fan for the over-the-wing (OTW) engine is presented. The fan has 28 blades. Aerodynamically, the fan blades were designed for a composite blade, but titanium blades were used in the experimental fan as a cost savings measure.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134915
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  • 91
    Publication Date: 2019-06-27
    Description: Energetic (energies greater than 1.6 and 3.9 MeV) trapped electron fluxes observed at the synchronous altitude during 1974 and 1975 by an experiment aboard ATS-6 exhibit a modulation in intensity which is correlated with the passage of sector-structure boundaries of the interplanetary magnetic field past the earth. The electron fluxes reach equilibrium intensities during the time the magnetosphere is in a given IMF sector; these fluxes are highest in the fall for (+) sectors and highest in the spring for (-) sectors.
    Keywords: SPACE RADIATION
    Type: Geophysical Research Letters; 3; May 1976
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  • 92
    Publication Date: 2019-06-27
    Description: The process of trapped particle absorption by the inner Jovian satellites is considered in detail taking into account both the particle and satellite motions in a magnetic dipole field which is displaced from the center of the planet and tilted with respect to the planetary rotation axis. An expression is derived for computing the sweeping time at a given satellite, defined as the time required for the satellite to sweep up a given fraction of the trapped particles within its sweeping region. By making use of the sweeping time and the radial diffusion equation of particle transport approximate expressions for the diffusion coefficient are derived. Measurements obtained by Pioneer 10 are then used to obtain estimates of the diffusion coefficient at the orbits of Io and Europa. We find that the diffusion coefficient is a function of energy and magnetic latitude for electrons in the energy range 0.7-14 MeV.
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 81; Mar. 1
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  • 93
    Publication Date: 2019-06-27
    Description: A cosmic gamma-ray burst is described which was observed from a balloon with a double-scatter gamma-ray telescope. The observed burst had a rise time of about 0.15 sec, a duration of 0.11 sec, and variations on a time scale of 5 msec. The variations are shown to imply a maximum source dimension of 1500 km. The integral energy distribution of the burst is determined along with the total energy above 0.5 MeV. The direction of the source is found, with 90% confidence, to be limited to a circle with a radius of 25 deg centered at +39 deg galactic latitude and 40 deg galactic longitude. Two additional candidate bursts observed with the same telescope are briefly discussed.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 203; Feb. 1
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  • 94
    Publication Date: 2019-06-27
    Description: Declining U.S. oil reserves and escalating energy costs underline the need for reducing fuel consumption in aircraft engines. The most promising unconventional aircraft engines based on their potential for fuel savings and improved economics are identified. The engines installed in both a long-range and medium-range aircraft were evaluated. Projected technology advances are identified and evaluated for their state-of-readiness for application to a commercial transport. Programs are recommended for developing the necessary technology.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-135065 , PWA-5434
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  • 95
    Publication Date: 2019-06-27
    Description: The acoustic tests and data analysis for a 0.508-scale fan vehicle of a 111,300 newton (25,000 pound) thrust, full-size engine, which would have application on an advanced transport aircraft, is described. The single-stage advanced technology fan was designed to a pressure ratio of 1.8 at a tip speed of 503 m/sec (1,650 ft/sec) to achieve the desired pressure ratio in a single-stage fan with low radius ratio (0.38), and to maintain adequate stall margin. The fan has 44 tip-shrouded rotor blades and 90 outlet guide vanes. The two basic approaches taken in the acoustic design were: (1) minimization of noise at the source, and (2) suppression of the generated noise in the inlet and bypass exhaust duct. Suppression of the generated noise was accomplished in the inlet through use of the hybrid concept (wall acoustic treatment plus airflow acceleration suppression) and in the exhaust duct with extensive acoustic treatment including a splitter. The goal of the design was attainment of twenty effective perceived noise decibels (20 EPNdB) below current Federal Air Regulation noise standards for a full-scale fan at the takeoff, cutback, and approach conditions. The suppression goal of FAR 36-20 was not reached, but improvements in the technology of both front and aft fan-noise suppression were realized. The suppressed fan noise was shown to be consistent with the proposed federal regulation on aircraft noise.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-134894
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  • 96
    Publication Date: 2019-06-27
    Description: Additional data obtained from the Apollo-16 and -17 missions, together with collateral calculations on background radiation effects, have enabled an improved subtraction of unwanted backgrounds from the diffuse cosmic gamma-ray data previously reported from Apollo-15. As a result, the 1- to 10-MeV spectrum is lowered significantly and connects smoothly with recent data at other energies. The inflection reported previously is much less pronounced and has no more than a 1.5-sigma significance. Sky occultation by the Apollo-16 spacecraft shows the bulk of the 0.3- to 1-MeV radiation to be diffuse. The analysis of spurious backgrounds points to important improvements for future experiments designed for this spectral region.
    Keywords: SPACE RADIATION
    Type: NASA-TM-X-71150 , X-682-76-128
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  • 97
    Publication Date: 2019-06-27
    Description: Computer program performance results of a Mach 6 hypersonic research engine during supersonic and subsonic combustion modes were presented. The combustion mode transition was successfully performed, exit surveys made, and effects of altitude, angle of attack, and inlet spike position were determined during these tests.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-TM-X-72822
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  • 98
    Publication Date: 2019-06-27
    Description: A brief summary of previous work carried out on end wall flow phenomena is presented with major emphasis on annulus wall boundary layer.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-148310
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  • 99
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2019-06-27
    Description: The major tasks undertaken were (1) analytical and laboratory experiments on the propagation of sound from sources near a flat surface of finite acoustic impedance; (2) laboratory experiments dealing with the reflection of sound from finite sized plane patches; and (3) the diffraction of sound by wedge-and trapezoidal-shape barriers. In addition, a series of measurements were made of the background noise levels for various jet flow conditions in the Anechoic Noise Facility of the Langley Research Center's Acoustic and Noise Reduction Laboratory.
    Keywords: AIRCRAFT PROPULSION AND POWER
    Type: NASA-CR-148321 , FTR-2
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  • 100
    Publication Date: 2019-06-27
    Description: Improved instrumentation suitable for measuring aircraft noise and sonic booms is described. An electric current proportional to the sound pressure level at a condenser microphone is produced and transmitted over a cable and amplified by a zero drive amplifier. The converter consists of a local oscillator, a dual-gate field-effect transistor mixer, and a voltage regulator/impedance translator. The improvements include automatic tuning compensation against changes in static microphone capacitance and means for providing a remote electrical calibration capability.
    Keywords: AIRCRAFT PROPULSION AND POWER
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