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  • Other Sources  (689)
  • NASA Technical Reports  (689)
  • GEOPHYSICS  (449)
  • AIRCRAFT PROPULSION AND POWER  (240)
  • 1975-1979  (689)
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  • 1900-1904
  • 1976  (689)
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  • 1975-1979  (689)
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  • 1
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    Mathematical modelling of undrained clay behavior (1976)
    In:  CASI
    Details
    Publication Date: 2006-08-09
    Description: The proposed general analytical model describes the anisotropic, elastoplastic, path-dependent, stress-strain properties of inviscid saturated clays under undrained conditions. Model parameters are determined by using results from strain-controlled simple shear tests on a saturated clay. The model's accuracy is evaluated by applying it to predict the results of other tests on the same clay, including monotonic and cyclic loading. The model explains the very anisotropic shear strength behavior observed for weak marine clays.
    Keywords: GEOPHYSICS
    Type: NASA. Langley Res. Center Advan. in Eng. Sci., Vol. 1; p 95-102
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  • 2
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    Geodynamics experiment MA-128 (1976)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: The Apollo Soyuz Test Project Geodynamics Experiment was performed to assess the feasibility of tracking and recovering high frequency components of the earth gravity field by utilizing a synchronous orbiting tracking station such as Applications Technology Satellite 6. Two prime areas of data collection were selected for this experiment. The first area is the center of the African continent, and the second area is the Indian Ocean depression centered at latitude 5 N and longitude 75 E. Preliminary results show that the detectability objective of the experiment has been achieved in both areas as well as in several additional anomalous areas around the globe. Gravity anomalies of the Karakoram and Himalayan mountain ranges of ocean trenches, and of the Diamantina depth are specific examples.
    Keywords: GEOPHYSICS
    Type: Apollo-Soyuz Test Project; 16 p
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  • 3
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    Doppler tracking experiment MA-089 (1976)
    In:  CASI
    Details
    Publication Date: 2006-01-12
    Description: The Doppler tracking experiment was designed to test the feasibility of improved mapping of earth gravity field anomalies by means of the low-low satellite-to-satellite tracking method. All prescribed data have been retrieved and are currently being reduced and analyzed. Baseline data taken while the docking module was still attached to the command and service module indicated that the equipment operated satisfactorily. The efficacy of the two frequency ionospheric correction method has been demonstrated, and preliminary reduction of a data sample has successfully removed extraneous signatures down to the 50-millihertz level, where the rotational motion of the docking module is revealed. Photographs of the docking module, taken shortly after jettison, show that its rotation was stable.
    Keywords: GEOPHYSICS
    Type: NASA. Lyndon B. Johnson Space Center Apollo-Soyuz Test Project; 31 p
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  • 4
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    Earth's bowshock and its vicinity (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Phenomena associated with the bowshock, such as its thickness, velocity, and associated waves are described. There are transverse waves radiating away from the shock and at times stationary waves fixed to it. Reflected protons generate waves far upstream. Electrostatic waves occur in the shock.
    Keywords: GEOPHYSICS
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  • 5
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    Heat budget of ionospheric electrons (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Heat input calculations were detached from solar extreme UV data and monatomic oxygen densities were derived from simultaneously measured data sets (ion composition 146-191 km) in a study of the heat budget of ionosphere electrons. Earlier inferences that cooling predominates over heating are supported. A search for additional heat sources or a revision of the cooling rates is recommended, by way of balancing the heat budget. Importance is attached to electron cooling by fine structure excitation of monatomic oxygen.
    Keywords: GEOPHYSICS
    Type: Annales de Geophysique; 32; Oct
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  • 6
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    The mesosphere (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The mesosphere is an atmospheric region characterized by a negative gradient of solar energy absorption and temperature. Although the distribution of most minor constituents is dominated by photochemistry, vertical transport does have a pronounced effect on many of them. The basic dynamic principles are discussed along with their application to the important mesospheric motions: acoustic-gravity waves, tides, planetary-scale waves, and eddy motions. Oxides of nitrogen and hydrogen are also examined which strongly influence the balance of odd oxygen (O and O3). Brief discussions of the chemistry of carbon compounds and of excited species are also included. The chemistry of ionic species in the mesosphere is very important because it strongly influences the propagation and absorption of radio waves. Because of ion clustering and negative-ion formation, such chemistry is extremely complex. The current state of knowledge is discussed in some detail. The principles involved in constructing models for predicting the distribution of minor constituents, both neutral and ionic, are presented.
    Keywords: GEOPHYSICS
    Type: Geophysical Surveys; 2; 1976
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  • 7
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    Coincident observations of ionospheric troughs and the equatorial plasmapause (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Electron-density observations made in the topside ionosphere by the Ariel 4 and Isis 2 satellites are examined in conjunction with results obtained by Explorer 45 when it traversed the near-equatorial plasmapause with one hour (both UT and MLT) of the Ariel and Isis traversals of the same L coordinate. Both dusk and night observations are analyzed, and an attempt is made to show that depressions in ionospheric electron density occur in the vicinity of the plasmapause field line. It is concluded that the electron distributions observed in the electron-density troughs at 550 km near dusk by Ariel and at 1400 km near midnight by Isis do not always parallel variations in the light-ion distribution inferred from the Explorer plasmapause traversals and that there appears to be no specific feature of the main ionospheric trough which can be used to identify the plasmapause field line except in a statistical sense.
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science; 24; Dec. 197
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  • 8
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    Some aspects of the stratospheric Cl-ClO-Cl cycle - Possible roles of ClO, ClNO3 and HOCl (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The possible inhibitory effect of excited ClO produced during chlorine-sensitized ozone decomposition on the stratospheric Cl-ClO-Cl cycle is investigated. Collisional deactivation of excited ClO is discussed, chemical reactions involving excited ClO are examined, and the possible roles of HO2 and NO2 in weakening the Cl-ClO-Cl cycle are evaluated. It is noted that the formation of HOCl through a reaction between ClO and HO2 implies that the Cl-ClO-Cl cycle has not been completed.
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science; 24; Dec. 197
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  • 9
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    Effects of the atmosphere on remote sensing (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The interaction between electromagnetic radiation and the earth's atmosphere is considered, taking into account windows in the electromagnetic spectrum, solar and terrestrial radiation, physical properties of the atmosphere, and clouds. The characteristics of upwelling radiation in the visible wavelengths are discussed along with infrared radiation and microwaves. Attention is given to radiant emittance, radiance, contrast, effects of atmospheric turbulence, ocean color, and questions concerning the classification of surface features with the aid of computers.
    Keywords: GEOPHYSICS
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  • 10
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    Magnetospheric whistler ducts observed by ISIS satellites (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The latitudinal width of the magnetospheric whistler duct has been estimated by the first and final invariant latitudes of whistler echoes and the conservation of the magnetic flux for the centered dipole field, using 105 whistler echoes in ISIS VLF data received at Kashima, Japan for 1972-1973. The latitudinal distribution of whistler duct occurrence shows a maximum at invariant latitudes of 40-45 degrees near the maximum occurrence latitude of ground whistlers. The radial width of magnetospheric whistler duct in the geomagnetically equatorial plane increases with invariant latitude of the geomagnetic flux tube in which whistlers propagate.
    Keywords: GEOPHYSICS
    Type: Radio Research Laboratories; vol. 23
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  • 11
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    Terrestrial kilometric radiation. I - Spatial structure studies (1976)
    In:  Other Sources
    Details
    Publication Date: 2011-08-17
    Description: Observations of lunar occultations of earth at 250 kHz, obtained with the Radio Astronomy Explorer 2 satellite, have been used to derive two-dimensional maps of the location of the sources of terrestrial kilometric radiation (TKR). By examining the two-dimensional source distributions as a function of the observer's location (lunar orbit) with respect to the magnetosphere, the average three-dimensional location of the emission regions can be estimated. Although TKR events at 250 kHz can often be observed at projected distances corresponding to the 250-kHz electron gyro or plasma level (about 2 earth radii), many events are observed much farther from earth (about 5 to 15 radii). On the dayside, emission was apparently observed in the region of the polar cusp and the magnetosheath at a magnetic latitude of about 70 deg; in the night hemisphere, emission is found to be associated with regions of the magnetotail at latitudes of at least 70 deg. The nightside emission is suggestive of a mechanism involving plasma-sheet electron precipitation in the premidnight sector.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Dec. 1
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  • 12
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    Thermospheric storms and related ionospheric effects (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: A comparative study of thermospheric storms for equinox and winter conditions is presented based on neutral-composition measurements from the Aeros-A neutral-atmosphere temperature experiment. The main features of the two storms as inferred from changes in N2, Ar, He, and O are described, and their implications for current theories of thermospheric storms are discussed. On the basis of the study of the F-region critical frequency measured from a chain of ground-based ionospheric stations during the two storm periods, the general characteristics of the ionospheric storms and the traveling ionospheric disturbances are described. It is suggested that the positive and negative phases of ionospheric storms are different manifestations of thermospheric storms.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Oct. 1
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  • 13
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    The Nimbus 4 infrared spectroscopy experiment. III - Observations of the lower stratospheric thermal structure and total ozone (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Dec. 20
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  • 14
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    Field-aligned currents observed by the Ogo 5 and Triad satellites (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The Triad (at a height of 800 km) and Ogo 5 (in the high altitude magnetosphere) magnetic field observations have shown the existence of a field-aligned current system consisting of currents flowing in the polar cap boundary layer and those flowing in another layer located equatorward of the former. In the polar cap boundary layer (identified as the high-latitude boundary of the plasma sheet in the nightside magnetosphere), the current flows into the ionosphere on the morning side and away from the ionosphere on the afternoon side. In the lower-latitude layer, the current directions are reversed. The current in the polar cap boundary layer is considered as the primary field-aligned current system.
    Keywords: GEOPHYSICS
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  • 15
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    Geomagnetic storm effects on the thermosphere and the ionosphere revealed by in situ measurements from OGO 6 (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The temporal response of the densities of upper-atmospheric ion and neutral constituents to a particular geomagnetic storm is studied using simultaneous ion and neutral-composition data obtained by the OGO 6 satellite during consecutive orbits at altitudes greater than 400 km. The investigated constituents include H(+), O(+), N2, O, He, and H. Derivation of the H density is reviewed, and the main effects of the storm are discussed, particularly temporal and global variations in the densities. It is found that: (1) the H and He densities began to decrease near the time of sudden commencement, with the decrease amounting to more than 40% of the quiet-time densities during the maximum stage at high latitudes; (2) the O and N2 densities exhibited an overall increase which began later than the change in H and He densities; (3) the H(+) density decreased differently in two distinct regions separated near the low-latitude boundary of the light-ion trough; and (4) the O(+) density showed an increase during earlier stages of the storm and decreased only in the Northern Hemisphere during the recovery phase. Certain physical and chemical processes are suggested which play principal roles in the ionospheric response to the storm
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science; 24; Nov. 197
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  • 16
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    Diffusive isothermal partitioning in a layered medium with geologic applications (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The diffusive isothermal partitioning of solute in a layered two-phase material has been analyzed to help elucidate the phenomenon of solute partitioning in multiphase lunar and terrestrial materials and to estimate the cooling history of samples. After reviewing the physical chemistry of partitioning and the case of an infinite one-dimensional diffusion couple, we solve in analytic form the case of a finite one-dimensional couple. The solution can be used to estimate cooling histories or to interpret laboratory experiments on partitioning. A sample calculation is included.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Nov. 10
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  • 17
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    On the magnetic mirroring as the basic cause of parallel electric fields (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Among the different proposed mechanisms for generating parallel electric fields, magnetic mirroring of charged particles seems to be the most plausible. In the present paper, it is suggested that magnetic mirroring is the basic cause of parallel electric fields in the magnetosphere and that the magnetic mirroring effect may be able to form the basis of an auroral theory that can remove a major portion of the ambiguity of observations. In the model proposed, the parallel electric field is due to a magnetic confinement of a negatively charged hot collision-free plasma. A transfer of electron gyroenergy into wave energy tends to weaken this confinement; if this energy transfer becomes too strong, the parallel potential gradient will break down. Hence, from this model, in contrast to certain other models of parallel electric fields, only a small fraction of the total auroral particle energy may be expected to be transformed into electromagnetic wave energy during the acceleration process.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Nov. 1
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  • 18
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    Energetics of the midlatitude thermosphere (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Thermospheric energetics is examined from the point of view of atomic and molecular processes which convert solar EUV radiative energy into kinetic energy of the ambient electron, ion, and neutral gases. The energy flow from photon to photoelectron-ion pair through energy loss and ion-molecule transfer to eventual electron-ion recombination is traced in detail. Upper and lower bounds are placed on the efficiency of conversion of radiative to thermal energy. Implications for the question of consistency of measured solar EUV fluxes and ionospheric models are discussed.
    Keywords: GEOPHYSICS
    Type: Journal of Atmospheric and Terrestrial Physics; 38; Aug. 197
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  • 19
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    Dynamical effects in the distribution of helium in the thermosphere (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The paper discusses some phenomena, mainly observed by satellites, which illustrate the use of helium as a tracer for studying the morphology and history of atmospheric responses to energy inputs of varying amplitudes and durations. The effects observed include (1) the annual north-south excursion of the sub-solar point producing the winter helium bulge, (2) the 24-hour diurnal variation, where the helium density peak is phase-shifted to the morning in the lower thermosphere, (3) high latitude magnetospheric heating of the thermosphere, with helium indicating regions of probable upwelling of the heated gas, and (4) gravity wave formation and propagation, with the attendant implications for transport of energy from one region of the atmosphere to another.
    Keywords: GEOPHYSICS
    Type: Journal of Atmospheric and Terrestrial Physics; 38; Aug. 197
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  • 20
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    Algorithms for computing the geopotential using a simple density layer (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Several algorithms have been developed for computing the potential and attraction of a simple density layer. These are numerical cubature, Taylor series, and a mixed analytic and numerical integration using a singularity-matching technique. A computer program has been written to combine these techniques for computing the disturbing acceleration on an artificial earth satellite. A total of 1640 equal-area, constant surface density blocks on an oblate spheroid are used. The singularity-matching algorithm is used in the subsatellite region, Taylor series in the surrounding zone, and numerical cubature on the rest of the earth.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Sept. 10
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  • 21
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    Molecular oxygen abundances in the thermosphere from atmosphere Explorer-C ion composition measurements (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Sept. 1
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  • 22
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    V.L.F. emission from ring-current electrons (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Characteristics of VLF emissions detected by satellite in association with enhancements of ring-current electrons during magnetic storms and substorms are described along with the associated enhancements in electron intensities and the anisotropies of the ring-current electron distribution. It is shown that the emissions are observed only when the satellite is outside the plasmasphere, that the beginning of the emissions coincides with the satellite's encounter with the large electron fluxes in that region, and that the increase in electron intensities associated with the observed emissions is limited only to low-energy electrons. The frequency distributions of emissions with peak frequencies above and below half the electron gyrofrequency at the equator is analyzed. The bimodal frequency distribution of the equatorial whistler-mode emissions is explained in terms of different production regions for emissions at frequencies above and below half the equatorial electron gyrofrequency.
    Keywords: GEOPHYSICS
    Type: Nature; 263; Sept. 2
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  • 23
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    Lidar measurement of stratospheric dust from St. Augustine Volcano (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: The detection of a stratospheric dust layer of probable volcanic origin over Hampton, Va., on the evening of Jan. 28, 1976, with a 20-inch lidar system is reported. A digitized cathode-ray-tube trace of a return signal from altitudes of 12 to 24 km on January 28 is provided, and it is shown that 38% of the return was due to stratospheric aerosol. Noting that measurements on January 22 and February 2 showed no traces of this stratospheric dust layer, trajectories of dust-laden air parcels are followed from initiation at 0000 GMT on January 24 at the St. Augustine Volcano on Augustine Island, Alaska (59 deg N, 153 deg W). Analysis of the trajectories indicates that dust injected into the stratosphere at 59 deg N, 153 deg W could have been transported to Virginia in about 4 days. It is concluded that if the St. Augustine Volcano was the source of the dust, at least 23 deg of meridional transport from polar latitudes was observed.
    Keywords: GEOPHYSICS
    Type: American Meteorological Society; vol. 57
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  • 24
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    Composition effects in thermospheric gravity waves (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Classical linearized gravity wave theory is employed to derive relationships between amplitude ratios and phase angles of atmospheric constituents undergoing acoustic-gravity wave oscillations. These results are compared with recently reported Atmospheric Explorer-C satellite data. Calculated amplitude and phase characteristics, for a large class of pure internal gravity wave oscillations, are in accord with the AE-C satellite measurements.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters; 3; Dec. 197
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  • 25
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    OH emission intensity measurements during the 1969 NASA Airborne Auroral Expedition (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Absolute intensity measurements of the (8, 6) OH band obtained during 10 flights of the December 1969 NASA Auroral Airborne Expedition are presented. Nightglow intensities higher by a factor of 2 than the usual values are recorded during flights 8, 14, and 15. The OH variations are compared with the evolution of the green line and O2(1 Delta g) emissions measured by other experimenters on board the aircraft. Before sunrise the twilight variations of OH down to a solar depression angle of 5 deg show a rapid decrease. A theoretical prediction of the OH, O I 5577 A, and O2(1 Delta g) emissions is evaluated by means of an extensive time-dependent oxygen-hydrogen model of the 25- to 150-km region. Twilight decrease of the OH emission is interpreted in terms of mesospheric ozone photodissociation. Nighttime variations of the emissions may be reproduced if modifications of the dynamic regime are introduced into the model.
    Keywords: GEOPHYSICS
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  • 26
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    Topside optical view of the dayside cleft aurora (1976)
    In:  Other Sources
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    Publication Date: 2011-08-17
    Description: Photometers on the ISIS-II spacecraft provide a view of the atomic oxygen 5577-A and 6300-A emissions and the N2(+) 3914-A emission detected as dayside aurora in the magnetospheric cleft region. The 6300-A emission forms a continuous and permanent band across the noon sector, at about 78 deg invariant latitude, with a defined region of maximum intensity that is never less than 2 kR (uncorrected for albedo) and is centered near magnetic noon. There are significant differences in the intensity patterns on either side of noon and their responses to geomagnetic activity. Discrete 3914-A auroral forms appear within this region at preferred locations that cannot be precisely specified but which tend to the poleward edge of the 6300-A emission in the evening and the equatorward edge in the morning, where the difference between the two emissions is greatest. It is concluded that the discrete auroras observed by all-sky cameras in the day sector follow the 6300-A emission through the cleft region, though a definite cleft boundary is not defined.
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science; 24; Oct. 197
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  • 27
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    Effect of nearby supernova explosions on atmospheric ozone (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: An investigation has been conducted of the probable effects of a nearby supernova event on the ozone layer of the earth. It is found that the ozone depletion, although smaller than that estimated by Ruderman (1974), is still significant, and could, as a result of cosmic rays, extend over periods of time from 1000 to 10,000 years. However, the probability of the occurrence of such an event within the past 100 million years appears to be low. The calculated ozone depletion seems to be the major effect of a supernova on a earth-like planet at a distance in the range from 5 to 10 pc.
    Keywords: GEOPHYSICS
    Type: Nature; 263; Sept. 30
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  • 28
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    Evolution of the ionosphere (1976)
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    Publication Date: 2011-08-16
    Description: Studies were made of the electron density profiles at various stages of atmospheric evolution, with the assumption that the atmospheric composition has changed due to the gradual increase of oxygen while the nitrogen level has remained constant. The result of model calculations indicates that when the oxygen content is less than about 1% of the present earth's atmosphere level, the major ions in the F2 region will change from O(+) to N(+). The maximum number density of N(+) ions reaches approximately 10 million per cu cm because of the absence of a rapid loss mechanism for N(+). The height of the N(+) ion density peak is much lower than the height of the F2 layer peak of the current ionosphere.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Sept. 1
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  • 29
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    Ion chemistry of N2/+/ and the solar ultraviolet flux in the thermosphere (1976)
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    Publication Date: 2011-08-16
    Description: We have analyzed daytime composition measurements in the thermosphere from Atmosphere Explorer-C by use of a theory of the ion chemistry. Predicted and measured N2(+) densities are compared to infer global variation of the solar ionizing flux. Results indicate that the solar flux of Hinteregger measured on Atmosphere Explorer-C provides an adequate basis for the calculation of solar ultraviolet photoionization rates. The role of metastable species is examined, and theoretical O+(2D) densities are presented.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Aug. 1
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  • 30
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    The interpretation of ionospheric radio drift measurements. IX - Direct comparisons between field-aligned ion drifts by incoherent scatter and Kinesonde measurements (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: GEOPHYSICS
    Type: Journal of Atmospheric and Terrestrial Physics; 38; July 197
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  • 31
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    Representation of magnetic fields in space (1976)
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    Publication Date: 2011-08-16
    Description: Several mathematical methods which are available for the description of magnetic fields in space are reviewed. Examples of the application of such methods are given, with particular emphasis on work related to the geomagnetic field, and their individual properties and associated problems are described. The methods are grouped in five main classes: (1) methods based on the current density, (2) methods using the scalar magnetic potential, (3) toroidal and poloidal components of the field and spherical vector harmonics, (4) Euler potentials, and (5) local expansions of the field near a given reference point. Special attention is devoted to models of the magnetosphere, to the uniqueness of the scalar potential as derived from observed data, and to the L parameter.
    Keywords: GEOPHYSICS
    Type: Reviews of Geophysics and Space Physics; 14; May 1976
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    Stratospheric ozone as viewed from the Chappuis band (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Total stratospheric ozone values above high-altitude stations in southern California from 1912 to 1950 and northern Chile from 1918 to 1948 are determined using data obtained by the Smithsonian Astrophysical Observatory, including transmission measurements made in the Chappuis band (0.5 to 0.7 micron). The results show that at both sites, total ozone amounts commonly exhibit variations of as much as 20% to 30% on time scales ranging from months to decades. Consideration of the amount of incident solar energy absorbed by the Chappuis band suggests that ozone acts as a shutter on the incoming solar radiation and provides a trigger mechanism between solar activity and climatic change.
    Keywords: GEOPHYSICS
    Type: Nature; 261; May 27
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    Nitric oxide formation by meteoroids in the upper atmosphere (1976)
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    Publication Date: 2011-08-16
    Description: The process of nitric oxide formation during atmospheric entry of meteoroids is analyzed theoretically. An ablating meteoroid is assumed to be a point source in a uniform flow with a continuum regime evolving in its wake. The amount of nitric oxide produced by high-temperature reactions of air in the continuum regime is calculated by numerical integration of chemical-rate equations. The results, when summed over the observed mass, velocity, and entry-angle distributions of meteoroids, provide annual global production rates of nitric oxide as a function of altitude. The peak production of nitric oxide is found to occur at altitudes between 90 and 100 km, the total annual rate being about 40 million kg. The present results suggest that the large concentration of nitric oxide observed below 95 km could be attributed to meteoroids instead of photodissociation of nitrogen.
    Keywords: GEOPHYSICS
    Type: Atmospheric Environment; 10; 7, 19; 1976
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  • 34
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    Field-aligned fluxes in the geomagnetic equator (1976)
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    Publication Date: 2011-08-16
    Description: During 12 electron injection events observed by Explorer 45 during the December, 1971, and February, 1972, in magnetic storms it was found that the lowest observable pitch angle particles (down to 7 degrees in one case) arrived first. Pitch angle dispersion and shell-splitting effects are shown to be inadequate explanations for most of these pitch angle distributions. It is suggested that parallel electric fields may be supplying 1- to 5-keV electrons to the magnetosphere from the ionosphere. Various models of parallel electric fields are discussed.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Apr. 1
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    Cyclotron side-band emissions from ring-current electrons (1976)
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    Publication Date: 2011-08-16
    Description: The paper examines temporal variations in electron energy spectra and pitch-angle distributions during a VLF-emission event observed by Explorer 45 in the main phase of a magnetic storm. It is noted that the observed event occurred outside the plasmasphere on the night side of the magnetosphere and that the dusk-side plasmapause had a double structure during the event. It is found that the VLF emissions consisted of two frequency bands, corresponding to the whistler and electrostatic modes, and that there was a sharp band of 'missing emissions' along frequencies equal to half the equatorial electron gyrofrequency. A peculiar pitch-angle distribution for high-energy electrons (50 to 350 keV) is noted. It is concluded that the VLF-producing particles were enhanced low-energy (about 5 keV) ring-current electrons which penetrated into the night side of the magnetosphere from the magnetotail plasma sheet and which drifted eastward after encountering the steep gradient of the geomagnetic field.
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science; 24; Apr. 197
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  • 36
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    Deuteron whistler and trans-equatorial propagation of the ion cyclotron whistler (1976)
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    Publication Date: 2011-08-16
    Description: The paper investigates two unusual types of ion cyclotron whistlers that were found in the low-latitude topside ionosphere by analyzing ISIS VLF electric-field data received at Kashima, Japan. One type is characterized by an asymptotic frequency equal to one half the local proton gyrofrequency; the asymptotic frequency of the other type corresponds to the minimum proton gyrofrequency along the geomagnetic field line passing through the satellite. The observations are compared with theoretical spectrograms of the ion cyclotron whistlers computed for appropriate model distributions of electrons and ions in the topside ionosphere. It is found that the whistlers with the asymptotic frequency of one half the local proton gyrofrequency are deuteron whistlers and that the other whistlers are due to the transequatorial propagation of proton or deuteron whistlers originating in the southern hemisphere.
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science; 24; Apr. 197
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  • 37
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    A parameterization for the absorption of solar radiation by water vapor in the earth's atmosphere (1976)
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    Publication Date: 2011-08-16
    Description: A parameterization for the absorption of solar radiation as a function of the amount of water vapor in the earth's atmosphere is obtained. Absorption computations are based on the Goody band model and the near-infrared absorption band data of Ludwig et al. A two-parameter Curtis-Godson approximation is used to treat the inhomogeneous atmosphere. Heating rates based on a frequently used one-parameter pressure-scaling approximation are also discussed and compared with the present parameterization.
    Keywords: GEOPHYSICS
    Type: Journal of Applied Meteorology; 15; Jan. 197
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  • 38
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    Composition waves in the thermosphere (1976)
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    Publication Date: 2011-08-16
    Description: Neutral-composition waves excited by auroral heat sources are investigated. For horizontal wavelengths of the order of 1000 km, it is concluded that diffusion processes (1) play a significant role such that deviations from diffusive equilibrium prevail for He throughout the thermosphere; (2) produce phase differences of about 220 deg (or -140 deg) between He and N2, and (3) account for He amplitudes comparable to those of N2. These results basically explain recent AE-C satellite measurements which have revealed an anticorrelation between the heavier and lighter constituents of the thermosphere. The calculations also indicate that temperature and N2 concentration are generally out of phase by about 100 deg.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Feb. 1
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  • 39
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    Apollo 16 far ultraviolet imagery of the polar auroras, tropical airglow belts, and general airglow (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Far-ultraviolet imagery of the earth in the wavelength ranges from 1050 to 1600 A and from 1250 to 1600 A was obtained from the lunar surface during the Apollo 16 mission on Apr. 21, 1972. The images have an angular resolution of about 2 arcmin (230-km linear resolution) and have been quantitatively analyzed to obtain absolute intensities and spatial distributions of the polar auroras (both wavelength ranges), the day and night airglow, and tropical airglow belts (1250-A to 1600-A wavelength range). The observations are consistent with previous results obtained from the OGO-4 spacecraft, but they have also provided details on the spatial distributions of the various emissions over an entire hemisphere at a single time. A general night airglow, at least in the Northern Hemisphere, is indicated.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Feb. 1
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  • 40
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    Perturbation theory in thermosphere dynamics (1976)
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    Publication Date: 2011-08-16
    Description: It is shown that density and pressure throughout the thermosphere can be adequately described in a logarithmic expansion that provides a sound basis for the application of perturbation theory. This expansion eliminates most of the important nonlinearities associated with density variations. On the basis of this expansion, the validity of perturbation theory can be extended to cover a large variety of atmospheric conditions in which the relative temperature amplitude is less than 0.5 and wind velocities are significantly less than the speed of sound.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Mar. 1
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  • 41
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    Wind-enhanced escape with application to terrestrial helium (1976)
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    Publication Date: 2011-08-16
    Description: We derive a simple expression for the escape flux which takes into account horizontal winds at the exobase. The escape flux is shown to increase with the wind velocity and becomes much larger than the Jeans escape flux for velocities approaching the thermal velocity. This model is applied to terrestrial He-4, where we determine the conditions required for wind-enhanced escape to contribute to the overall He-4 budget. For completeness, we also derive an expression for the escape flux when only a vertical wind is present at the exobase.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Mar. 1
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  • 42
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    Magnetic fields of the magnetosheath (1976)
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    Publication Date: 2011-08-16
    Description: The magnetic field of the magnetosheath is most naturally discussed in terms of its steady state and its fluctuating components. The theory of the steady-state field is quite well developed, and its essential features have been confirmed by observations. The interplanetary field is convected through the bow shock, where its magnitude is increased and its direction changed by the minimal amount necessary to preserve the normal component across the shock. Convection within the magnetosheath usually increases the magnitude still further near the subsolar point and further distorts the direction until the field is aligned approximately tangent to the magnetopause. Fluctuations of the magnetosheath field are very complex, variable, and not well understood. Transverse waves are often dominant at frequencies below 0.002 Hz, and compressional waves are often dominant at somewhat higher frequencies. Perturbation vectors of hydromagnetic waves tend to be aligned with the shock and magnetopause surfaces. Magnetosheath waves may be generated upstream, within the magnetosheath, at the bow shock, or at the magnetopause.
    Keywords: GEOPHYSICS
    Type: Reviews of Geophysics and Space Physics; 14; Feb. 197
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    A comparison of one-dimensional theoretical models of stratospheric minor constituents (1976)
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    Publication Date: 2011-08-16
    Description: The density profiles of stratospheric minor constituents are compiled from several one-dimensional theoretical models that have appeared in the literature. The models are compared with each other and also with observations if data are available. The similarity and disparity of the models are clarified and discussed. If a large difference exists among the models, attempts are made to interpret it as much as possible in terms of the physical and chemical data employed in each model. The inadequacy of one-dimensional models in calculating the realistic ozone density distributions and the problems related to it are briefly discussed.
    Keywords: GEOPHYSICS
    Type: Reviews of Geophysics and Space Physics; 14; Feb. 197
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  • 44
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    Diurnal and seasonal variations in atomic and molecular oxygen inferred from Atmosphere Explorer-C (1976)
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    Publication Date: 2011-08-16
    Description: Mass-spectrometer measurements of O and N2, obtained with the Atmosphere Explorer-C satellite during December 1974 and January 1975, are used to derive the O2 concentration near 250 km from several ionization reactions. In order to separate temperature effects from diffusion effects, the measured O and inferred O2 concentrations are employed to determine, under the assumption of diffusive equilibrium, the O/N2 and O2/N2 ratios at 120 km. It is found that the latitudinal and diurnal variations in the O concentration at 120 km are consistent with previous results obtained with OGO 6 and that the O2 concentration in the Northern (winter) Hemisphere is about twice as high as that in the Southern (summer) Hemisphere. The possible importance of photodissociation in the diurnal O2 variations is discussed.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters; 3; Feb. 197
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  • 45
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    High-latitude troughs and the polar cap boundary (1976)
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    Publication Date: 2011-08-16
    Description: OGO 6 observations of troughs in the thermal plasma densities in the topside ionosphere are discussed. Ion mass spectrometer measurements were correlated with energetic electron detector and electric field measurements. It is shown that the variation of ion composition at high latitudes is complex and frequently characterized by mid-latitude and high-latitude density depression. Prominent high-latitude troughs in the atomic ion (H, He, O) distributions were seen to lie frequently near the polar cap boundary. This indicates that these troughs are unrelated to the plasmapause which is found on closed magnetic field lines away from the trapping boundary. The production of the high-latitude troughs is shown to be related to enhancements in the soft electron flux and/or to the convection electric field.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Feb. 1
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  • 46
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    Satellite measurements of ion composition and temperatures in the topside ionosphere during medium solar activity (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Information on both ion density and temperature is obtained from analysis of Retarding Potential Analyzer data from the OGO-4 and Explorer-31 satellites. Results obtained from data in the altitude range of 700-2000 km during medium solar activity are presented. An attempt is made to describe the major altitude variations of ion densities and temperatures at middle and low latitudes. The transition heights, where the heavier and lighter ions are equal, are found to be about 1600 and 1300 km at middle and low latitudes, respectively, for daytime and 700 km at night for middle latitudes. Based on the observed data and using diffusive equilibrium as a first-order approximation, topside ionospheric composition models are given for medium solar activity.
    Keywords: GEOPHYSICS
    Type: Journal of Atmospheric and Terrestrial Physics; 38; Apr. 197
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  • 47
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    Rb, Sr and strontium isotopic composition, K/Ar age and large ion lithophile trace element abundances in rocks and glasses from the Wanapitei Lake impact structure (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Shock metamorphosed rocks and shock-produced melt glasses from the Wanapitei Lake impact structure have been examined petrographically and by electron microprobe. Eleven clasts exhibiting varying degrees of shock metamorphism and eight impact-produced glasses have been analyzed for Rb, Sr and Sr isotopic composition. Five clasts and one glass have also been analyzed for large ion lithophile (LIL) trace element abundances including Li, Rb, Sr, and Ba and the REE's. The impact event forming the Wanapitei Lake structure occurred 37 m.y. ago based on K/Ar dating of glass and glassy whole-rock samples. Rb/Sr isotopic dating failed to provide a meaningful whole-rock or internal isochron. The isotopic composition of the glasses can be explained by impact-produced mixing and melting of metasediments.
    Keywords: GEOPHYSICS
    Type: Geochimica et Cosmochimica Acta; 40; Jan. 197
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  • 48
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    Absorption cross sections of some atmospheric molecules for resonantly scattered O I 1304-A radiation (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Absorption cross sections for O2, N2, CO2, CH4, N2O, and CO have been measured at each of the lines of the atomic oxygen triplet at 1302, 1305, and 1306 A. Radiation resonantly scattered from oxygen atoms at a temperature of about 300 K was used for the line source. Absorber temperatures were also near 300 K. Direct application of the Lambert-Beer absorption equation yielded pressure-dependent cross sections for carbon monoxide at each line of the O I triplet. Reasons for this apparent dependence are presented and discussed.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; July 1
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    Tests and comparisons of satellite-derived geoids with Skylab altimeter data (1976)
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    Publication Date: 2011-08-16
    Description: During the Skylab 4 mission, the S-193 radar altimeter was operated nearly continuously for a revolution around the world on Jan. 31, 1974. This direct measurement to the sea surface has provided an independent basis for the evaluation of the precision of global geoids computed from satellite-derived earth gravity models. This paper presents comparisons between the Skylab data and several recent gravity models published by Goddard Space Flight Center, the Smithsonian Astrophysical Observatory, and the National Oceanic and Atmospheric Administration. The differences between the altimeter geoid and the satellite geoids were as large as 20 m, rms values ranging from 8 to 10 m. These differences also indicated a systematic long-wavelength variation (about 100 deg) not related to error in the Skylab orbits. Truncation of the models to degree and order 8 did not eliminate the long-wavelength variation, but in every case the rms agreement between the satellite geoids and the altimeter geoid was slightly improved. Orbits computed with the truncated models were found to be inferior to those computed with the complete models.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; July 10
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    A comparison of measured and inferred temperatures from AEROS-B (1976)
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    Publication Date: 2011-08-17
    Description: The neutral composition and the temperature data obtained from the AEROS-B Neutral Atmosphere Temperature Experiment (NATE) and the Neutral and Ion Mass Spectrometer (NIMS) are compared, and the general validity of inferring gas temperatures from N2 and Ar density profiles is examined by comparing them with the in situ measured values of the neutral kinetic temperature (NATE). At times serious discrepancies are noted between the inferred and the measured temperature. This is particularly evident during periods of increased magnetic activity when the normally observed latitudinal variations are apparently modulated by waves propagating from the polar region to low latitudes. Under these conditions the N2 and Ar densities and temperature oscillations are usually out of phase, and the temperatures inferred from N2 and Ar at a given point become meaningless.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters; 3; Dec. 197
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    Quasi-biennial geomagnetic variation caused by the sun (1976)
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    Publication Date: 2011-08-17
    Description: Clear evidence for the existence of a quasi-biennial geomagnetic variation is shown by an analysis of annual averages of the horizontal (H) component of the geomagnetic field observed at five observatories. The analysis uses a numerical filter, which is equivalent to taking the second order time derivative of the time series. The cause for the variation is external to the earth because its amplitude depends on magnetic activity. The second order time derivative of H is well correlated with the corresponding time derivatives of the relative sunspot number and 10.7 cm solar flux. It is suggested that quasi-biennial oscillations observed in the geomagnetic field, cosmic rays, stratospheric zonal wind and temperature, total ozone, and other meteorological parameters could be produced by a common cause on the sun.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters; 3; Nov. 197
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    Dependence of the charge exchange lifetimes on mirror latitude (1976)
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    Publication Date: 2011-08-17
    Description: The dependence of the charge exchange lifetimes on the mirror latitude for ions mirroring off the geomagnetic equator has been re-computed using improved hydrogen distribution models. The Chamberlain model, with the input parameters determined by recent satellite observations, has been used to define the spatial distribution of the neutral hydrogen environment through which the ring current ions traverse. The resultant dependence of the charge exchange lifetime, tau, on mirror latitude, lambda-m, is best fit by the approximation tau-m = tau-e cos 3.5 lambda-m, where tau-e is the charge exchange lifetime for the equatorial particles.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters; 3; Nov. 197
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    Solar activity geomagnetic field and terrestrial weather (1976)
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    Publication Date: 2011-08-17
    Description: Spectral analysis is used as an independent test of the reported association between interplanetary-magnetic-field structure and terrestrial weather. Spectra of the Ap geomagnetic activity index and the vorticity area index for the years from 1964 to 1970 are examined for common features that may be associated with solar-related phenomena, specifically for peaks in the power spectra of both time series with periods near 27.1 days. The spectra are compared in three ways, and the largest peak with the smallest probability estimate is found to occur at a period of 27.49 days. This result is considered to be statistically significant at the 98% level. It is concluded that the period derived from the Ap spectrum is related to solar rotation and that the analysis provides supporting evidence for a connection between the vorticity area index and solar activity.
    Keywords: GEOPHYSICS
    Type: Nature; 264; Nov. 18
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  • 54
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    Discrepancy between electron heating and cooling rates derived from Atmosphere Explorer-C measurements (1976)
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    Publication Date: 2011-08-17
    Description: The present theory of electron temperature in the daytime mid-latitude ionosphere is tested by using Atmosphere Explorer-C measurements. In the region below 300 km, where a balance is expected between electron heating by photoelectron impact and electron cooling to ions and neutrals, we find an imbalance in which the cooling rate is consistently higher than the heating rate. The shapes of the altitude profiles also differ substantially. The cooling rate has a sharp peak at about 220 km, while the heating rate exhibits a broad peak about 30 km lower. Improved agreement is achieved at higher altitudes by using an oxygen fine structure loss rate smaller by a factor of 2, based on more recent collision strength calculations. Although this improves the overall agreement of the heating and cooling rates, the shape discrepancy remains, and the new cooling rate falls consistently below the heating rate below 200 km.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Nov. 1
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    Chinese records on the correlation of heliocentric planetary alignments and earthquake activities (1976)
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    Publication Date: 2011-08-17
    Keywords: GEOPHYSICS
    Type: Icarus; 29; Nov. 197
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  • 56
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    New fine structure cooling rate (1976)
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    Publication Date: 2011-08-16
    Description: One of the dominant electron cooling processes in the ionosphere is caused by electron impact induced fine structure transitions among the ground state levels of atomic oxygen. This fine structure cooling rate is based on theoretical cross sections. Recent advances in the numerical cross section determinations to include polarization effects and more accurate representations of the atomic target result in new lower values. These cross sections are employed in this paper to derive a new fine structure cooling rate which is between 40% and 60% of the currently used rate. A new generalized formula is presented for the cooling rate (from which the fine structure cooling rate is derived), valid for arbitrary mass and temperature difference of the colliding particles and arbitrary inelastic energy difference.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters; 3; Sept
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    A mid-latitude ozone model for the 1976 U.S. standard atmosphere (1976)
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    Publication Date: 2011-08-16
    Description: A mid-latitude northern hemisphere model of the daytime ozone distribution in the troposphere, stratosphere, and lower mesosphere has been constructed. Data from rocket soundings in the latitude range of 45 deg N + or - 15 deg N, results of balloon soundings at latitudes from 41 to 47 deg N, and latitude gradients from satellite ozone observations have been combined to produce estimates of the annual mean ozone concentration and its variability at heights up to 74 km for an effective latitude of 45 deg N. This model is a revision for heights above 26 km of the tentative mid-latitude ozone model, included in the U.S. Standard Atmosphere Supplements, 1966, and has been adopted for use in the U.S. Standard Atmosphere, 1976.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Aug. 20
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    Injection boundary dynamics during a geomagnetic storm (1976)
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    Publication Date: 2011-08-16
    Description: A series of proton and electron injections were observed by Explorer 45 associated with several substorms during the main phase of the Feb. 24, 1972 geomagnetic storm. The 1- to 290-keV protons and 1- to 560-keV electrons were observed in the evening quadrant up to L of about 5.2. A model distorted dipole magnetic field and McIlwain's E3 convection electric field were used to backtrack the energy-dispersed electron and proton fluxes to their source at the time of injection. The source turns out to be a region extending over several earth radii outside an injection boundary. In the night magnetosphere, the inferred injection boundary is displaced inward with each successive substorm. The energy dispersion plot of the particles injected during orbit 314 indicates that as the energy of the observed particles decreases there is a smooth transition to the position of the plasmapause. This suggests that for that substorm the injection boundary and the plasmapause were one and the same. The proton 'noses' reported by Smith and Hoffman (1974) are discussed.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Aug. 1
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    Aeroacoustics: Jet noise, combustion and core engine noise (1976)
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    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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    Comparison of the San Marco 3 Nace neutral composition data with the extrapolated Ogo 6 empirical model (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: An investigation is conducted concerning the feasibility to extrapolate the data of the Ogo 6 empirical composition model to altitudes which are lower than 450 km. Extrapolated Ogo 6 model densities are, therefore, compared with data obtained in the Neutral Atmospheric Composition Experiment (Nace) carried out during the time from April to November 1971. The results of the investigation support the conclusions of an earlier comparison of Ogo 6 and Nace data conducted by Newton et al. (1973).
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Mar. 1
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    Behavior of the sodium and hydroxyl nighttime emissions during a stratospheric warming (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The behavior of the sodium and hydroxyl nighttime emissions during a stratospheric warming has been studied principally by use of data from the airglow photometers on the OGO 4 satellite. During the late stages of a major warming, both emissions increased appreciably, with the sodium emission returning to normal values prior to the decrease in the hydroxyl emission. The emission behaviors are attributed to temperature and density variations from 70 to 94 km, and a one-dimensional hydrostatic model for that altitude range is used to calculate the effects on the emissions and on the mesospheric ozone densities. These results support the existence of a warming in the upper part of the mesosphere that is correlated with a major stratospheric warming.
    Keywords: GEOPHYSICS
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    Measurements of atmospheric ozone made from a GASP-equipped 747 airliner Mid-March, 1975 (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: This paper presents data on the ozone mixing ratio, static air temperature, wind speed, and wind direction obtained at altitudes from 8 to 12 km during several flights of a commercial airliner equipped with a fully automated air-sampling system developed for the NASA Global Atmospheric Sampling Program (GASP). The objectives of GASP are reviewed, and the data-gathering techniques are described. Two data sets are discussed which illustrate variations of the upper-tropospheric and lower-stratospheric ozone mixing ratios as a function of geographical location and aircraft altitude. Good agreement is found between the GASP data and the tropopause height obtained from National Meteorological Center gridded data.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters; 3; Feb. 197
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  • 63
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    Contributions to the National Geodetic Satellite Program by Goddard Space Flight Center (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The major scientific contributions of Goddard Space Flight Center to the National Geodetic Satellite Program between 1965 and 1973 are presented and discussed. The primary results described are the determination of the earth's gravitational field from satellite tracking and surface gravimeter data to an accuracy of about 4 mGal for wavelengths of about 1000 km and larger; the construction of a detailed geoid suitable for geodetic, tectonic, and altimetry data analysis accurate to about 2 m over continents and to 2-5 m over the northeast Pacific and Atlantic oceans; and the positioning of globally distributed tracking stations to an accuracy of 5-10 m for the interconnecting of local geodetic datums. In addition, work on the observation of the earth and ocean tidal perturbations of satellites is discussed and reviewed.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Feb. 10
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  • 64
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    Observations of magnetospheric ionization enhancements using upper hybrid resonance noise band data from the RAE 1 satellite (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research vol. 81; Jan. 1
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  • 65
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    Repeated sharp flux dropouts observed at 6.6 earth radii during a geomagnetic storm (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A number of repeated rapid flux dropouts have been observed at 6.6 earth radii by the low-energy proton detectors on board the ATS 6 satellite during the July 4-6, 1974, geomagnetic storm period. These rapid flux changes are caused by the fact that the outer boundary of the trapped radiation region moves back and forth past the satellite. Although a tilting field line configuration can cause the boundary to pass the satellite, as has frequently been reported in the literature, the boundary is shown to be distorted by a large surface wave traveling eastward around the earth. The maximum velocity of the wave was observed to be about 40 km/s.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Jan. 1
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  • 66
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    Source location measurements of terrestrial kilometric radiation obtained from lunar orbit (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Two-dimensional source locations of individual terrestrial kilometric radiation (TKR) events have been measured by the Radio Astronomy Explorer-2 (RAE-2) spacecraft in lunar orbit. Although the average source location at 250 kHz is above the polar regions near the earth (r nearly 2-3 earth radii), approximately 10% of the events occur at a distance larger than 7 earth radii from the earth. Furthermore, there is considerable evidence for multiple sources and source motion over the time scale of tens of minutes. Recent TKR mechanism theories which assume that the emission occurs at or near the local electron plasma or gyrofrequency would predict generation much closer to the earth's surface. Alternative emission mechanisms or special propagation conditions are required to explain many TKR events.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters; 3; Jan. 197
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  • 67
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    Polar enhancements of nightglow emissions near 6230A (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Night airglow emissions near 6230A, as observed from the Ogo 4 spacecraft in 1967-8, show enhancements at polar latitudes by more than a factor of ten over mid and low latitude values. The enhancements are generally not symmetrical with either the north pole or the auroral oval. They are attributed in part to increases in the Meinel band emissions of OH, particularly as associated with a stratospheric warming event, and in part to increases in nitric oxide densities in the lower thermosphere.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters; 3; Jan. 197
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  • 68
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    An evaluation of temperature profiles from falling sphere soundings (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: An evaluation of 30 pairs of high-altitude inflatable falling spheres and independent thermistor soundings with a mean rocket-launch-time separation of 27 min shows average temperature differences within 6 C at 32-70 km, except for an average difference of 10 C at 68 km near Mach 1 in the sphere descent curve. The mean difference is exhibited as a negative bias (sphere temperature colder) for which various explanations are considered. The rms temperature differences are greatest near 50 km (7 C) and 68 km (11 C). From 70 to approximately 87.5 km, confidence in the reliability of the sphere temperature soundings is based on the 'repeatability' of pairs of sphere soundings taken within 20 min, temperature differences generally being less than 10 C. Illustrations of large atmospheric variations measured by the sphere soundings are given along with verification from independent measurements.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Jan. 20
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  • 69
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    Kinematical constraints on the observation of slow monopoles at the top of the atmosphere (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Relativistic kinematics of monopole production and propagation in earth's atmosphere and magnetic field have been examined in the light of the observation of a magnetic monopole by Price et al. It has been shown that the observed monopole cannot result from nuclear interactions in the atmosphere and that the extraterrestrial origin of this monopole is very unlikely.
    Keywords: GEOPHYSICS
    Type: Physical Review Letters; 36; Jan. 19
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  • 70
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    The approximation of particulate scattering coefficients in the determination of total ozone (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: GEOPHYSICS
    Type: Royal Meteorological Society; vol. 102
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  • 71
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    Earth tides, volcanos and climatic change (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The effect of variations in tidal stresses on the earth caused by the sun and moon on volcanic activity and climate is investigated. A statistically significant correlation is found between the derivatives of the envelopes of peak tidal stresses at high northern latitudes and the mean temperature of the Northern Hemisphere as reflected in oxygen isotope ratios in the Greenland ice cap. It is suggested that variations in tidal stresses cause changes in the amount of stratospheric dust produced by volcanic activity, which affects the thickness of the stratospheric dust veil and the atmospheric radiation balance. For a simple model, periodic variations in tidal stress account for 13% of the variance in the ice-core temperature record.
    Keywords: GEOPHYSICS
    Type: Nature; 261; June 24
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  • 72
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    Ring current proton decay by charge exchange (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Explorer 45 (S3-A) measurements were made during the recovery phase of the moderate magnetic storm of February 24, 1972, in which a symmetric ring current had developed and effects due to asymmetric ring current losses could be eliminated. It was found that after the initial rapid decay of the proton flux, which is a consequence of the dissipation of the asymmetric ring current, the equatorially mirroring protons in the energy range 5-30 keV decayed throughout the L value range of 3.5-5.0 at the charge exchange decay rate calculated by Liemohn (1961). After several days of decay, the proton fluxes reached a lower limit where an apparent equilibrium was maintained, between weak particle source mechanisms and the loss mechanisms, until fresh protons were injected into the ring current region during substorms. While other proton loss mechanisms may also be operating, the results indicate that charge exchange is more than sufficient as a particle loss mechanism for the storm time proton ring current decay.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; June 1
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  • 73
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    Direct measurements of natural tropospheric levels of OH via an aircraft borne tunable dye laser (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters; 3; June 197
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  • 74
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    Local vertical motions and kinetic temperature from AE-C as evidence for aurora-induced gravity waves (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: In situ measurements of local vertical neutral particle motions have been made using the Neutral Atmosphere Temperature Instrument (NATE) on Atmosphere Explorer-C from observations of the direction of flow of neutral particles into the antechamber of the sensor (mass spectrometer). Values ranging from a few to more than 80 meters per second have been observed. The data show vertical motions greater than a few meters per second to be present most of the time, the magnitude being a function of many factors including magnetic activity, location, and magnetic storm history. In a specific case, it is concluded that the observed vertical motions and kinetic temperature are evidence of a travelling disturbance originating as a gravity wave in the auroral zone.
    Keywords: GEOPHYSICS
    Type: Geophysical Research Letters; 3; June 197
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  • 75
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    Effects on the plasmasphere of irregular electric fields (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A conservative convection electric field model developed by Volland (1973) to describe the solar wind induced plasma flow within the inner magnetosphere is modified to include a noisy spatial component. Under steady state conditions such a random component will result in spatial irregularities in the thermal plasma density distribution in the vicinity of the plasmapause. Spatial irregularities in the convection can produce longitudinally restricted perturbations near the plasmapause, some of which are detached from the main body of the plasmasphere. Temporal variations in the midnight to noon flow intensity produce elongated extensions of the plasmasphere, but even short period variations of the overall magnitude of the convection cannot produce longitudinally localized perturbations in the thermal plasma distribution. Convection models based on the 3 hr magnetic index K sub p yield plasmasphere structures which are qualitatively similar to those based on shorter period variations, but the exact location at any given time of the plasmapause is dependent upon the characteristic time scale employed.
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science; 24; July 197
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  • 76
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    Transient thermospheric heating and movement caused by an auroral electric field (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science; 24; Aug. 197
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  • 77
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    Diurnal variation of thermal plasma in the plasmasphere (1976)
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    Publication Date: 2011-08-16
    Description: All of the OGO-5 light ion density measurements were used to determine the average global topology of the equatorial plasmasphere density distribution. The variation of the light ion equatorial density at L less than or equal to 3.2 with local time was deduced by determining the average density observed within one hour of a specific local time and within 0.1 of a given L coordinate. The average H(+) density showed a semidiurnal variation with peaks near noon and midnight. The He(+) observations also revealed multiple peaks throughout the day but with smaller amplitudes than those of H(+). At L above 3.2 plasma trough conditions increase the scatter of densities. The average variation of the H(+) density with L within the plasmasphere is found to be steepest near midnight and can be least-squares fitted equally well to either an exponential variation or to a power law.
    Keywords: GEOPHYSICS
    Type: Planetary and Space Science; 24; Aug. 197
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  • 78
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    Comparisons of measured and theoretical thermospheric daily composition variations (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A comparison of the diurnal component of the daily variation in the neutral composition data from the San Marco 3 Nace (Neutral Atmospheric Composition Experiment) mass spectrometer at 220, 250, and 280 km, the OGO-6 model data at 450 km, rocket measurements of nitrogen between 140 and 300 km, and the two-constituent theoretical model of Mayr and Volland (1973) gives good agreement for molecular nitrogen and atomic oxygen. The Nace and rocket measurements overlap in altitude, and there is good agreement in the amplitude and phase of the diurnal and semidiurnal components for molecular nitrogen. The helium diurnal amplitude and phase of the theoretical model are in fair agreement with the Nace results, while the amplitude from the OGO-6 model at 450 km is much larger than the model predicts, a result suggesting that the OGO-6 model diurnal amplitude may be overestimated as the result of an incomplete separation of local-time and seasonal effects.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; May 1
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  • 79
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    A model study of diurnal behavior of the ionosphere and the protonosphere coupling (1976)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A new method to study dynamic behavior of the ionosphere-protonosphere coupling within the plasmasphere is developed and used to calculate ion distributions above 500 km using observed electron densities at 500 km. The method is based on the relation between the total magnetic flux tube content of H(+) above some reference height (e.g., 3000 km) and the H(+) flux at that height, which is uniquely determined by the coupled momentum and continuity equations for the quasi-steady state. The O(+) profile is perturbed from diffusive equilibrium only by ion drag with H(+). The time dependency is taken into account by applying self-consistent boundary conditions which are obtained from the solution of the time-dependent equation for the tube content of H(+). Calculations are carried out for two models. The first model deals with the ion dynamics in a tube of force which rotates with the earth. In the second model, effects of the cross-L plasma drifts are considered. Both models produce diurnal variations of H(+) and O(+) densities near 1000 km similar to observational results.
    Keywords: GEOPHYSICS
    Type: Journal of Geophysical Research; 81; Apr. 1
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  • 80
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    Turbofan compressor dynamics during afterburner transients (1976)
    In:  CASI
    Details
    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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  • 81
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    Assessment of Variable-Cycle Engines for Supersonic Transports (1976)
    In:  CASI
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    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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  • 82
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    Considerations of high altitude emissions (1976)
    In:  CASI
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    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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    Technology for controlling emissions of oxides of nitrogen from supersonic cruise aircraft (1976)
    In:  CASI
    Details
    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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    Composite materials research in support of supersonic propulsion systems (1976)
    In:  CASI
    Details
    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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  • 85
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    YF-12 propulsion research program and results (1976)
    In:  CASI
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    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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  • 86
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    Control of propulsion systems for supersonic cruise aircraft (1976)
    In:  CASI
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    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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  • 87
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    Supersonic cruise inlets for variable-cycle engines (1976)
    In:  CASI
    Details
    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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  • 88
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    Variable stream control engine concept for advanced supersonic aircraft: Features and benefits (1976)
    In:  CASI
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    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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  • 89
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    Advanced Supersonic Technology Study: Engine Program Summary. Supersonic Propulsion: 1971 to 1976 (1976)
    In:  CASI
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    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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  • 90
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    Component test program for variable-cycle engines (1976)
    In:  CASI
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    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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  • 91
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    Review of measurement and testing problems (1976)
    In:  CASI
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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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  • 92
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    Review of measurement and testing problems (1976)
    In:  CASI
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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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  • 93
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    Summary of the general aviation manufacturers' position on aircraft piston engine emissions (1976)
    In:  CASI
    Details
    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
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 94
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    Alternative general-aircraft engines (1976)
    In:  CASI
    Details
    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
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 95
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    Emissions and new technology programs for conventional spark-ignition aircraft engines (1976)
    In:  CASI
    Details
    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
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 96
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    Future development programs (1976)
    In:  CASI
    Details
    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
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 97
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    Avco Lycoming/NASA contract status (1976)
    In:  CASI
    Details
    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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    NASA TECHNICAL REPORTS
  • 98
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    Introduction to NASA contracts (1976)
    In:  CASI
    Details
    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
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 99
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    Future development programs (1976)
    In:  CASI
    Details
    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
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 100
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    Flight test summary of modified fuel systems (1976)
    In:  CASI
    Details
    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
    Format: application/pdf
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    NASA TECHNICAL REPORTS
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