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  • Inorganic Chemistry  (752)
  • SPACE RADIATION  (429)
  • COMMUNICATIONS  (315)
  • Cell & Developmental Biology
  • 1970-1974  (1,683)
  • 1972  (1,683)
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  • 1970-1974  (1,683)
Year
  • 1
    Publication Date: 2005-11-30
    Description: A two-axis drive system is described for pointing a high gain antenna. Motion about each axis is provided by identical drive mechanisms. Only three gear passes are required to obtain the necessary 900:1 gear reduction. The drive system is a primary element of an experiment that will provide a real time data link between Nimbus and ground stations. Data are transmitted from Nimbus to the applications technology satellite, which relays the data to ground stations.
    Keywords: COMMUNICATIONS
    Type: NASA. Ames Res. Center 6th Aerospace Mech. Symp.; p 117-120
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  • 2
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    In:  CASI
    Publication Date: 2005-11-30
    Description: The Intelsat 4 communications satellite has two spot beam antennas which are pointed to selected land masses by gimbaled positioners. The positioners employ drive motors with electromagnetic brakes and jackscrews that are self-caging during the launch. The positioner uses dry lubricants for ball bearings, spur gears, screw and nut, and various journal bearings. A coefficient of friction of approximately 0.05 was demonstrated in vacuum operation. Success of the positioner was demonstrated on the first Intelsat 4 placed in orbit in January 1971. The developmental problems that were encountered and their solutions are discussed.
    Keywords: COMMUNICATIONS
    Type: NASA. Ames Res. Center 6th Aerospace Mech. Symp.; p 109-116
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  • 3
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    In:  CASI
    Publication Date: 2005-11-30
    Description: Measurements of the positions of the sources of solar radio bursts at decameter wavelengths, 20- to 60-MHz range, provide information about physical conditions in a region of the corona extending from about one-half to several solar radii from the surface of the sun. Position measurements in the 20- to 60-MHz range were made with the Clark Lake sweep-frequency grating interferometer. Although the resolution of the instrument is sufficient to measure source position accurately, the highly variable effect of refraction in the earth's ionosphere severely limits the observations, distorting position determinations to such an extent as to make much of the position data useless unless ionospheric refraction can be taken into account. A method was developed for the removal of the refractive effect from the data to permit determination of true source position. With this technique it is considered possible to measure spatial extent of radio sources that will provide information about emission processes and physical parameters in the corona.
    Keywords: COMMUNICATIONS
    Type: Significant Accomplishments in Sci., 1970; p 149-153
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  • 4
    Publication Date: 2005-11-30
    Description: A technique is described for reducing near-in sidelobes in spacecraft antennas by cancellation. This technique takes a small portion of the radiation from the antenna aperture and generates the near-in lobes, which are then fed out of phase relative to the main signal. Results of sample cases indicate that the first three lobes can be nearly eliminated at a 40% reduction in aperture efficiency.
    Keywords: COMMUNICATIONS
    Type: JPL Quart. Tech. Rev., Vol. 1, No. 4; p 34-42
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  • 5
    Publication Date: 2005-11-30
    Description: The GE experiment consisted of two types of detectors: plastics and glasses located in panel 2 and the lower half of panel 3. In panel 2, the entire exposed detector area of 14.7 by 22.6 cm was composed of 31 sheets of 0.025-cm polycarbonate plastic 9070-112. In panel 3, 39 sheets of 0.02-cm cellulose triacetate with no plasticizer made up the major volume fraction. The lower part of panel 3 contained five types of glass detectors. Particles that entered the array after it was folded were recognized, if they crossed from one sheet to another, by means of a 2-mm relative shift of alternate sheets.
    Keywords: SPACE RADIATION
    Type: NASA. Lyndon B. Johnson Space Center Apollo 16 Prelim. Sci. Rept.; 9 p
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  • 6
    Publication Date: 2005-11-30
    Description: During the Apollo 16 mission, a solar flare produced an enormous amount of low-energy nuclei, many orders of magnitude greater than the level inferred from studies of tracks in the window of the Apollo 12 spacecraft during a time when the sun was quiet. The differential energy spectrum of nuclei with Z less than or equal to 6 falls by seven orders of magnitude over the interval from 0.1 to 20 MeV/nucleon, then remains almost flat up to approximately 100 MeV/nucleon. The two parts correspond to contributions from the sun and from galactic cosmic rays. Any maximum in the spectrum occurs below the lowest energy studied.
    Keywords: SPACE RADIATION
    Type: NASA. Lyndon B. Johnson Space Center Apollo 16 Prelim. Sci. Rept.; 8 p
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  • 7
    Publication Date: 2005-11-30
    Description: All mineral detectors exposed on Apollo 16 had high surface track densities probably produced by a solar flare that occurred during the mission. The heavy ions followed a power law spectrum with exponent approximately 3 down to approximately 200 KeV/nucleon. The abundance of low-energy particle tracks observed in this flare may explain the high track densities observed in lunar dust grains. Pristine heavy-particle tracks in feldspar give long tracks. Shallow pits similar to those expected from extremely heavy solar wind ions were observed in about the expected number. Initial results give a low apparent value of neutron albedo relative to theory.
    Keywords: SPACE RADIATION
    Type: NASA. Lyndon B. Johnson Space Center Apollo 16 Prelim. Sci. Rept.; 14 p
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  • 8
    Publication Date: 2005-11-30
    Description: Investigations on the Fe-group nuclei track density vs depth in lunar rocks and Surveyor 3 TV camera filter glass were critically examined considering more factors than previously. The analysis gives a firmer basis to the observation of the preferential leakage of low energy Fe nuclei from the accelerating region of the sun. The track density gradients in lunar rock 12022 and filter glass are used to determine the lunar erosion rate of 3 angstroms/yr. Track gradients are less steep than predicted from energy spectrum observed in the Surveyor glass, perhaps due to sputtering. High densities of etchable tracks were found at all depths down to 60 cm in fines from Apollo cores and also in thin sections of the Pesjanoe, Pantar, and Fayetteville gas-rich meteorites. It is felt unlikely that suprathermal heavy ions were responsible for the high track densities.
    Keywords: SPACE RADIATION
    Type: NASA, Washington Analysis of Surveyor 3 Mater. and Phot. Returned by Apollo 12; p 221-226
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  • 9
    Publication Date: 2005-11-30
    Description: Particle tracks were investigated in the glass plate of a neutral density (clear flint) optical filter housed in the Surveyor 3 TV camera but exposed directly to space. The track density vs depth curve was determined and descends sharply from approximately 2.6 million tracks/sq cm at a depth of 3.6 mg/sq cm to about 35/sq cm at 700 mg/sq cm. Several tracks were of V-shapes characteristic of high energy induced fission. The erosion rate on the moon due to solar wind ions was determined from the energy spectrum, and was found to be low (0 to 2 x 10 to the minus 8th power cm/yr).
    Keywords: SPACE RADIATION
    Type: NASA, Washington Analysis of Surveyor 3 Mater. and Phot. Returned by Apollo 12; p 213-216
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  • 10
    Publication Date: 2005-11-30
    Description: The proton-produced Na-22 content of samples of Surveyor 3 TV camera, surface sampler scoop, and other components was determined by nondestructive gamma ray spectrometry. The contributions of the nine most prominent solar flares to Na-22 production were calculated to be 18 dpm/kg. The observed activity in the Surveyor 3 samples was 62 + or - dpm/kg. This indicates a galactic proton contribution of about 44 dpm/kg, which adjusted for spallation of Al gives a value of 42 dpm/kg. This is compared to measurements of 88 dpm/kg in the Lost City meteorite which had an orbit extending to 2.35 AU, with a 4 pi bombardment as compared to the 2 pi bombardment of the samples on the lunar surface. The agreement between Na-22 production in Surveyor 3 and the Lost City meteorite offers evidence that the galactic cosmic ray flux is almost the same at 1 Au and at 2.35 AU.
    Keywords: SPACE RADIATION
    Type: NASA, Washington Analysis of Surveyor 3 Mater. and Phot. Returned by Apollo 12; p 196-200
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  • 11
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    Publication Date: 2005-11-30
    Description: A spacecraft recorder was developed with the objective of functioning continuously for 5 years. The resulting design employed a metallic tape wound in a 200-turn helix. A direct drive, brushless dc torquer and servo speed control drove the recorder at 3 rpm for recording and 54 rpm for playback.
    Keywords: COMMUNICATIONS
    Type: 6th Aerospace Mech. Symp.; p 89-93
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  • 12
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    In:  CASI
    Publication Date: 2005-11-30
    Description: Nimbus 3 and 4 observations of ultraviolet active regions of the sun have been investigated. It is not clear what is producing these UV-active regions, however, it could be changes in the overall intensity of the solar continuum near the region of the temperature minimum, or the solar flux variations that have been seen could be due to a continuous type of absorption like that associated with the ionization limits of elements such as aluminum, silicon, or magnesium.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci., 1970; p 159-163
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  • 13
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    In:  CASI
    Publication Date: 2005-11-30
    Description: Intuition regarding the stability of MHD tangential discontinuities of solar wind has been borne out by a linear stability analysis of the MHD equations. In performing the calculation, the model used had no plasma flow and thus corresponded to the solar wind rest frame. The method calculated the change in total energy, plasma plus magnetic, due to the perturbation. This type of stability analysis is analogous to the test of the stability of an equilibrium point in a mechanical potential.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci., 1970; p 134-139
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  • 14
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    In:  CASI
    Publication Date: 2005-11-30
    Description: The ability of a theoretical solar wind model to predict the energy flux density due to heat conduction was investigated. In order to demonstrate this capability, the analysis used simultaneous data from the electron plasma experiment of Ogilvie and Lind, and the vector magnetic field data of Heppner and Sugiura on OGO-5. On the strength of two independent, different, and consistent experimental determinations of the conduction of heat flux by electrons at 149.6 gigameters(1 AU), it was determined that the models for the solar wind must be able to predict a value for the heat conduction in the range 0.007 to 0.008 in order to be in agreement with the observations.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci., 1970; p 144-148
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  • 15
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    Publication Date: 2005-11-30
    Description: The process of solar flare acceleration of interplanetary particles, as measured by the fifth orbiting solar observatory, is explained. Data show the acceleration proceeds in two stages: (1) particle acceleration by induced electric fields arising from annihilating magnetic fields at the beginning stages of flares, and (2) a Fermi acceleration mechanism operating in a shock front produced by the flare.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci., 1970; p 171-175
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  • 16
    Publication Date: 2005-11-30
    Description: Extreme value theory is examined to explain the cause of the bias and spread in performance of communications systems characterized by low bit rates and high data reliability requirements, for cases in which underlying noise is Gaussian or perturbed Gaussian. Experimental verification is presented and procedures that minimize these effects are suggested. Even under these conditions, however, extreme value theory test results are not particularly more significant than bit error rate tests.
    Keywords: COMMUNICATIONS
    Type: JPL Quart. Tech. Rev., Vol. 1, No. 4; p 58-68
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  • 17
    Publication Date: 2005-11-30
    Description: Predictions of surface and near surface blockiness using earth based radar measurements were made. Two polarizations of the radar echoes were measured - polarized and depolarized. Particular attention was given to the depolarized echoes. North Ray and South Ray Craters and a 512-m diameter lunar crater in the Flamsteed Ring were used for the study.
    Keywords: COMMUNICATIONS
    Type: NASA. Lyndon B. Johnson Space Center Apollo 16 Prelim. Sci. Rept.; 3 p
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  • 18
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    Publication Date: 2005-11-30
    Description: The purpose of the reported experiment was to determine the principal electromagnetic and structural properties of the lunar surface from the observation of command and service module (CSM) radio transmissions that were reflected from the lunar surface and received on earth. These transmissions emanate from the CSM communication systems at wavelengths of 13 cm (S-band) and 116 cm (very high frequency (VHF)). Lunar crustal properties such as dielectric constant, average slope and slope probability, density, small-scale surface roughness, and embedded rocks to a depth of 20 m may be determined. The results are proving to be most useful in understanding the processes that have produced and modified the crust and in distingushing between adjacent and subjacent geological units. The experimental observations are also of intrinsic interest in the study of electromagnetic scattering.
    Keywords: COMMUNICATIONS
    Type: NASA. Lyndon B. Johnson Space Center Apollo 16 Prelim. Sci. Rept.; 13 p
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  • 19
    Publication Date: 2005-11-30
    Description: Samples of glass from the Surveyor 3 TV camera filter were examined for particle tracks by optical and scanning electron microscopy. The corrected density value is 1.7 million + or - 0.1 million tracks/sq cm, and the track density vs depth curve is determined. Comparisons with other estimated and calculated data are discussed, and lack of agreement between data sets is considered. It is felt that considerable erosion occurs, and that erosion also occurs by a flaking of small thicknesses of material, possibly caused by solar wind irradiation.
    Keywords: SPACE RADIATION
    Type: NASA, Washington Analysis of Surveyor 3 Mater. and Phot. Returned by Apollo 12; p 209-212
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  • 20
    Publication Date: 2005-11-30
    Description: A silica glass window from Apollo 12 CM and a piece of flint glass from the Surveyor 3 camera filter were examined for Fe nuclei tracks. A large difference between observed and predicted track densitites was found. At low rigidity (or energy), the solar particle Fe/He ratio is much higher than the photospheric abundance ratio, but decreases with increasing rigidity until it approaches the photospheric value at a rigidity of about 500 MV. It is felt that the low-energy Fe tracks are of solar origin. The implications that heavy nuclei can be preferentially emitted from a source of energetic particles are discussed. Other conclusions are the following: Rocks exposed on the lunar surface for 10 million yr would accumulate about 6 x 10 to the 12th power tracks/sq cm, and the rate of radiation-induced erosion is about 10 to the -9 cm/yr. The lunar soil should contain heavily irradiated small grains, some with track densities of about 10 to the 12th power/sq cm that have flaked from radiation-damaged rock surfaces and some that were irradiated while at the top of the soil layer.
    Keywords: SPACE RADIATION
    Type: NASA, Washington Analysis of Surveyor 3 Mater. and Phot. Returned by Apollo 12; p 217-220
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  • 21
    Publication Date: 2005-11-30
    Description: The Apollo 16 SWC experiment is a continuation of the earlier experiments; however, an essential change was introduced in the solar wind particle collection technique. Platinum surfaces were incorporated in the collector foil, and use was made of a layer technique for distinguishing particles of different energies and different directions of arrival. The improvements and the expanded scope of the Apollo 16 experiment, relative to the earlier SWC experiments, can be summarized as follows: elimination of possible residual dust contamination by treating the platinum foil sections with dilute hydrofluoric acid before analysis; increased accuracy of solar wind argon abundance; determination of solar wind albedo; and search for helium in the energy range above approximately 40 KeV/nucleon.
    Keywords: SPACE RADIATION
    Type: NASA. Lyndon B. Johnson Space Center Apollo 16 Prelim. Sci. Rept.; 10 p
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  • 22
    Publication Date: 2005-11-30
    Description: The passionate dream of the oppressed solar flare forecaster is the scientific discovery of the cause, the energy source, and the observable antecedent conditions for the solar flare. This tunnel vision has had a profound and deleterious effect on the state-of-the-art. It has diverted attention from many promising approaches and relegated them to limbo. More importantly, it has actually inhibited the scientific search for the underlying physical mechanisms. Examples of neglected aspects of the problem cover the entire range from observing techniques and equipment to the availability and accuracy of the archived scientific data. A cursory inspection of this data leads to an obvious conclusion: there are at least two suns up there.
    Keywords: SPACE RADIATION
    Type: NASA, Washington Phys. of the Space Environment; p 157-171
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  • 23
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    Publication Date: 2005-11-30
    Description: The radar augmentation device (RAD) serves to increase the radar response of a target body and thus expedite radar acquisition. The design and development of the RAD are discussed with particular emphasis on technical problems that were encountered and solved. Discussions of the mode of operation of the RAD and the ground test history are also included.
    Keywords: COMMUNICATIONS
    Type: NASA. Ames Res. Center 6th Aerospace Mech. Symp.; p 65-72
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  • 24
    Publication Date: 2005-11-30
    Description: The He-4 and Ne-20 contents in sections of the Surveyor 3 support strut samples were determined by optical and scanning electron microscopy and are compared to the results of the Apollo solar wind composition (SWC) experiments. The He-4/Ne-20 ratio in the samples from the sunlit side of the strut was approximately 300; the ratios determined in Apollo 12 lunar fines and SWC foil were below 100. The He-4/He-3 ratios were also determined, and the ratio obtained from Surveyor 3 material is higher than those found with Apollo 11 and 12 SWC experiments. The effects of spallation by cosmic rays or solar protons, stripping by cosmic ray or energetic solar alpha particles, recycling of solar wind He and radiogenic Ne, He from terrestrial atmosphere, mass discrimination near the moon, mass dependence of trapping probability, diffusion, and contamination by lunar dust are considered.
    Keywords: SPACE RADIATION
    Type: NASA, Washington Analysis of Surveyor 3 Mater. and Phot. Returned by Apollo 12; p 201-208
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  • 25
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    Publication Date: 2005-11-30
    Description: Observations, made by the RAE satellite, of earth magnetospheric noise are reported. The observations show radio noise exists at 700 kHz and below. The results are included in graphs.
    Keywords: COMMUNICATIONS
    Type: Significant Accomplishments in Sci., 1970; p 75-80
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  • 26
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    Publication Date: 2005-11-30
    Description: The results of an investigation on the effects of earth seasonal changes on solar activity, particularly sunspots, are given. These results show corpuscular and electromagnetic activity increased during the equinoctial months. In addition the electromagnetic aspect tends to increase during the winter months. It was suggested that seasonal changes in sunspot numbers may be caused by the tidal forces and the processional torques exerted by the various planets in the solar atmosphere.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci., 1970; p 164-170
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  • 27
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    Publication Date: 2005-11-30
    Description: Hydromagnetic heating in the solar wind was investigated using the heating model in which fast-mode hydromagnetic waves propagate outward from below the base and deposit energy by collisionless damping. Ray paths were found by solving Hamilton's equations. As the ray propagates along its path, it will damp, supplying thermal energy to the solar wind gas. The strong agreement of these results with observations is clear indication that the primary nonthermal heat source in the solar wind is the collisionless damping of hydromagnetic waves.
    Keywords: SPACE RADIATION
    Type: Significant Accomplishments in Sci., 1970; p 140-143
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  • 28
    Publication Date: 2006-03-12
    Description: There are two types of experimental measurement errors of the Doppler data associated with the radio occultation, random and systematic. Random errors are due to thermal noise in the transmission channel, and the phase lock loop, and quantization error in the digital circuitry. These are called noise type errors. The systematic errors are due to geometric uncertainty and equipment phase instability. Considered is the amount of uncertainty, due to random measurement errors, in the refractivity profiles reconstructed by this type of indirect sensing experiment. A class of refractivity profiles is defined which approximately fit the set of measured data. Bounds are placed on the extent of this class of solution profiles. To accomplish this, the sensivity of the reconstructed refractivity profiles to errors in the measured quantity and the statistics of the errors in the measurement are examined.
    Keywords: COMMUNICATIONS
    Type: NASA. Ames Res. Center Math. of Profile Inversion; 5 p
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  • 29
    Publication Date: 2006-03-12
    Description: A review of exact techniques for determining the surface of a three-dimensional perfectly conducting body is given, followed by some new results on the uniqueness question concerning the number of measurements that may be required to explicitly determine the surface of the body. It is then shown that the inhomogeneous but spherically symmetric dielectric electromagnetic case is reducible to a scalar inverse problem that can be treated by known techniques.
    Keywords: COMMUNICATIONS
    Type: NASA. Ames Res. Center Math. of Profile Inversion; 11 p
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  • 30
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    Publication Date: 2006-02-22
    Description: An estimate of the antenna noise temperature and the uplink signal-to-noise ratio has been made for Bremsstrahlung radiation emitted by a spacecraft ion beam; a worst-case situation in which the spacecraft antenna is located in the exit plane of the ion beam and directed at varying angles into the ion beam is assumed. Numerical results of the antenna noise temperature versus antenna pointing angle are given for a typical set of ion beam and antenna pattern parameters. The uplink signal-to-noise ratio due to the ion beam noise alone is given in terms of a critical range in AU at which a typical ranging transmission is received with S/N = 0 db. The effects of the ion beam divergence angle and antenna distance on the ion beam are also presented. Results of the study show typical increases in the antenna noise temperature of about 0.2 K and critical ranges of the order of 3-5 AU. An ion engine thus generally introduces an undetectable level of noise into a spacecraft receiver.
    Keywords: COMMUNICATIONS
    Type: JPL Quart. Tech. Rev., Vol. 2, No. 2; p 61-71
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  • 31
    Publication Date: 2006-02-22
    Description: Optimal design concepts are presented for two- and three-channel telemetry modes in the context of the Mariner Venus-Mercury 1973 mission and the usefulness of interplex modulation techniques is discussed. These ideas are applied as an example to one Mariner Venus-Mercury 1973 telemetry mode to demonstrate that interplex can reduce the required total average power by more than 2 dB in some cases.
    Keywords: COMMUNICATIONS
    Type: JPL Quarterly Tech. Rev., Vol. 2, No. 1; p 143-151
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  • 32
    Publication Date: 2006-02-22
    Description: A peripheral drive belt on the Mariner Mars 1971 tape recorder failed when a thin longitudinal strip separated off one edge. Analysis showed that the most probable cause of failure occurred from flexural fatigue initiating in mechanically weak locations which are introduced into the belt during fabrication. Methyl ethyl ketone, which is employed as a cleaning solvent during fabrication, was found to cause permanent reduction in engineering properties of polyester and could have contributed to the reduction of the fatigue resistance. Fatigue properties of the polyester drive belt are reviewed for the operating condition, as well as the sensitivity of polyester to cleaning solvents and the origin of mechanically weak locations.
    Keywords: COMMUNICATIONS
    Type: JPL Quarterly Tech. Rev., Vol. 2, No. 1; p 82-99
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  • 33
    Publication Date: 2006-02-22
    Description: Methods were developed for measuring frictional forces acting on a magnetic tape in motion or at rest, as well as the extent of stick slip. The effects of factors such as temperature, humidity, kind of gaseous atmosphere, and tape speed on the frictional interaction between various tapes and heads were investigated. Results were instrumental in the selection of a tape for the Mariner Mars 1971 spacecraft. Studies are reported on the stick slip behavior of tapes and the performance of a metallic tape, compared with the usual plastic tapes.
    Keywords: COMMUNICATIONS
    Type: JPL Quarterly Tech. Rev., Vol. 2, No. 1.; p 100-106
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  • 34
    Publication Date: 2006-04-24
    Description: The results of the reduction of simultaneous observations of 29 meteors are presented in tabular form. Fragmentation of the observations is discussed along with the 50 meteors not yet reduced.
    Keywords: COMMUNICATIONS
    Type: Meteor Res. Program; p 83-99
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  • 35
    Publication Date: 2006-04-24
    Description: The procedures used in the analysis of television and simultaneous observations are described. Starting with the right ascension and declination of the meteor, the celestrial triangle formed by Sidell and the meteor is solved, and the epochs of the beginning and end of the meteor observation as recorded on the video tape are determined.
    Keywords: COMMUNICATIONS
    Type: Meteor Res. Program; p 69-76
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  • 36
    Publication Date: 2006-04-24
    Description: The original image-orthicon equipment used for simultaneous radar and optical observations is described. The adaptations made to enhance its usefulness for meteor observations, and the specialized calibration and photometric procedures developed for this purpose are also described. Some brief comments concerning the use of the secondary electron conduction vidicon are included.
    Keywords: COMMUNICATIONS
    Type: Meteor Res. Program; p 29-36
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  • 37
    Publication Date: 2006-04-26
    Description: A method is examined for calculating the error of experimental data from a standard neutron monitor with the multiplicity of neutron generation. It is shown that use of the Poisson distribution to estimate the real statistical error is inadequate. The method proposed is for analysis of low-amplitude periodicities in the cosmic-ray variations.
    Keywords: SPACE RADIATION
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 79-81
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  • 38
    Publication Date: 2006-04-26
    Description: Median noon absorption values for each month from 1964 through 1967, the diurnal variations of absorption on the regular world days, and the seasonal variations of absorption are given. The dependence of the absorption coefficient on sunspot number is analyzed.
    Keywords: COMMUNICATIONS
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 99-112
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  • 39
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    Publication Date: 2006-04-26
    Description: It is shown based on data on the cosmic-ray neutron component, ionospheric soundings, and measurements of cosmic radio-emission absorption at Vostok station (Antarctica) that the ionization of the lower ionosphere increases during low intensity of Forbush-type cosmic rays. This is manifested in increased absorption and the appearance of strong sporadic layers in the E-region.
    Keywords: SPACE RADIATION
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 74-77
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  • 40
    Publication Date: 2006-04-26
    Description: Features of the cosmic-ray variations in the geomagnetic pole region and a smooth decrease in the cosmic rays intensity as a result of increased solar activity are reported. A 66-day variation of the cosmic rays was registered, in agreement with the maximum frequency and power of solar chromospheric flares.
    Keywords: SPACE RADIATION
    Type: Morphology of the Quiet and Disturbed Ionosphere; p 113-116
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  • 41
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    In:  CASI
    Publication Date: 2006-04-24
    Description: Based on the assumption that the ionized column left behind a moving meteroroid is underdense, it is shown that radar observations of the column yield resonable aproximations to the meteoriod's speed and trajectory. The principles and procedures for finding a meteor's position and vector velocity from the observed data are also presented.
    Keywords: COMMUNICATIONS
    Type: Meteor Res. Program; p 51-68
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  • 42
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    Publication Date: 2006-04-24
    Description: The procedures for calibrating the antenna patterns of the Havana radar system are described along with the reduction of the measurements made using a dipole towed behind an airplane. The power-gain pattern for the north, south, and joint troughs of sites 3 and 4 are plotted.
    Keywords: COMMUNICATIONS
    Type: Meteor Res. Program; p 37-50
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  • 43
    Publication Date: 2006-04-24
    Description: A general description is given of the eight-station system at Havana which incorporated high-gain antennas and a powerful transmitter to reach faint meteors on the order of magnitude of plus 12. The station location, principle of system design, systems connections, transmitter, receivers, logics, range measurement, and recording are described.
    Keywords: COMMUNICATIONS
    Type: Meteor Res. Program; p 19-27
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  • 44
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    In:  CASI
    Publication Date: 2006-02-22
    Description: Accurate estimation of signal power is an important Deep Space Network (DSN) consideration. Ultimately, spacecraft power and weight is saved if no reserve transmitter power is needed to compensate for inaccurate measurements. Spectral measurement of the received signal has proved to be an effective method of estimating signal power over a wide dynamic range. Furthermore, on-line spectral measurements provide an important diagnostic tool for examining spacecraft anomalies. Prototype equipment installed at a 64-m-diameter antenna site has been successfully used to make measurements of carrier power and sideband symmetry of telemetry signals received from the Mariner Mars 1971 spacecraft.
    Keywords: COMMUNICATIONS
    Type: JPL Quart. Tech. Rev., Vol. 2, No. 2; p 18-24
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  • 45
    Publication Date: 2011-08-16
    Description: Demonstration that, during the process of dielectronic recombination, the energy of a recombined ion after a resonance capture and subsequent stabilization may still be higher than the first ionization limit. If that happens, a secondary autoionization can take place and reduce the recombination coefficient. The importance of this effect is considered for iron ions Fe(9+) to Fe(13+).
    Keywords: SPACE RADIATION
    Type: Astrophysical Letters; 10; Apr. 197
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  • 46
    Publication Date: 2011-08-16
    Description: Evaluation of gamma-ray spectra calculated for relativistic-electron bremsstrahlung interactions at cosmological distances under the assumption of a single power-law source spectrum for the electrons. It is concluded that such spectra cannot match the form of the observed cosmic gamma-ray spectrum above 1 MeV, as has previously been suggested.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 171; Jan. 15
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  • 47
    Publication Date: 2011-08-16
    Description: The effect of mode coupling has been calculated for radio waves partially reflected from the lower ionosphere at vertical incidence. Calculations were made for parameters appropriate to the partial reflection experiments (Belrose, 1970). The four reflection coefficients (two direct and two coupled) are calculated for a plane discontinuity using a matrix perturbation analysis. The ratios of coupled to direct reflection coefficients are calculated for a general one-dimensional reflecting layer using the coupled equations of Clemmow and Heading (1954). At the highest electron density considered, 10,000 per cu cm, about 10% of the reflected extraordinary wave amplitude might be due to coupling from the incident ordinary wave. The effect is smaller at lower electron density.
    Keywords: COMMUNICATIONS
    Type: Radio Science; 7; Apr. 197
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  • 48
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    Publication Date: 2011-08-16
    Description: Most atoms that are evaporated from interplanetary dust near the sun are quickly ionized and are probably carried away by the interplanetary magnetic field and the solar wind. The contribution of these heavy ions to the solar-wind flux has been estimated by using estimates of the mass required to maintain the zodiacal cloud. This contribution appears to be small compared with the heavy-ion flux of coronal origin. Many ions from dust remain singly ionized; some of these, such as Ca(+), can resonantly scatter solar radiation. The contribution of this interplanetary glow to the background of twilight glow has been estimated. Interplanetary glow may be detectable. Some atoms from dust may be accelerated by radiation pressure before being ionized. Estimates of velocities and fluxes for Fe indicate that this acceleration is not very effective.
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 77; Apr. 1
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  • 49
    Publication Date: 2011-08-16
    Description: Measurement of the solar wind electron integral spectrum yielding electron temperatures ranging from 100,000 to 400,000 K and having an average value of 182,000 K, electron densities having an average value of 4.6 per cu cm, and electron-temperature anisotropies ranging from 1 to 1.4. The electron temperature is found to be independent of solar-wind speed over the range from 290 to 675 km/sec. Comparison of the simultaneous alignment of the local magnetic-field vector with the direction of the electron-temperature anisotropy reveals a high correlation. Necessary conditions for the fire-hose instabilities were satisfied in the electron and proton components of the solar-wind plasma immediately behind an interplanetary shock.
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 77; Apr. 1
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  • 50
    Publication Date: 2011-08-16
    Description: A high-sensitivity scan of the galactic plane from 70 to 30 deg was performed to search for 2-20-keV X rays from supernova remnants. The spectra of five X-ray sources detected between 44 and 31 deg longitude are presented, of which only two might be associated with suggested supernova remnants. Upper limits are given for the 19 possible supernova remnants scanned.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 173; Apr. 15
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  • 51
    Publication Date: 2011-08-16
    Description: A common intermediary connecting frequency-noise calibration or testing of an oscillator to useful applications is the spectral density of the frequency-deviating process. In attempting to turn test data into predicts of performance characteristics, one is naturally led to estimation of statistical values by sample-mean and sample-variance techniques. However, sample means and sample variances themselves are statistical quantities that do not necessarily converge (in the mean-square sense) to actual ensemble-average means and variances, except perhaps for excessively large sample sizes. This is especially true for the flicker noise component of oscillators. This article shows, for the various types of noises found in oscillators, how sample averages converge (or do not converge) to their statistical counterparts. The convergence rate is shown to be the same for all oscillators of a given spectral type.
    Keywords: COMMUNICATIONS
    Type: IEEE Transactions on Communications; COM-20; Apr. 197
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  • 52
    Publication Date: 2011-08-16
    Description: Differential energy spectra of cosmic-ray protons and He nuclei have been measured for the first time by an ionization spectrometer flown at balloon altitudes. The energy range extended from 50 to more than 1000 GeV. The observed differential intensities can be represented with power-law spectra with a slope of -2.75 (plus or minus 0.03) for protons and of -2.77 (plus or minus 0.05) for He nuclei. The proton-to-He ratio is 26 (plus or minus 3) at 40 GeV/nucleon and is constant within errors up to 400 GeV/nucleon.
    Keywords: SPACE RADIATION
    Type: Physical Review Letters; 28; Apr. 10
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  • 53
    Publication Date: 2011-08-16
    Description: The use of magnetometers for azimuth determination of balloon-borne X-ray astronomy payloads is examined, with special emphasis placed on the experiments of the University of Adelaide Cosmic Ray Group. A critical evaluation is made of the effectiveness of the magnetometers, including discussion of effects due to geomagnetic field variations, magnetometer misorientation and spurious contaminant magnetic fields. Calibration techniques and details of in-flight performance are also presented.
    Keywords: SPACE RADIATION
    Type: Planetary and Space Science; 20; Mar. 197
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  • 54
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    Publication Date: 2011-08-16
    Description: Two current models for Eta Carinae are discussed. It is shown that the recently observed soft X-ray flux seems to indicate a surprisingly high density for the ambient gas around Eta Carinae, and that some useful constraints on models of this object may result from X-ray observations.
    Keywords: SPACE RADIATION
    Type: Nature Physical Science; 236; Mar. 20
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  • 55
    Publication Date: 2011-08-16
    Description: Description of a high-sensitivity wide-bandwidth 10.6-micron heterodyne receiver for space and ground operational use. The receiver includes a cooled HgCdTe infrared mixer diode, a conical scanner for spatial tracking, an acquisition channel for spatial search and station alignment, and an automatic frequency-control channel to maintain a fixed laser frequency offset. The infrared mixer is designed to provide nearly quantum-noise-limited operation over an extended range of mixer temperature, bias voltage, and intermediate frequency. The resultant experimental receiver has a measured noise equivalent power of less than 10 to the minus 19th W/Hz over the 15- to 40-MHz i.f. band for mixer temperatures from 85 to 115 K, and less than 2 x 10 to the minus 19th W/Hz up to 140 K. Mixer 3-dB cutoff frequencies as high as 420 MHz were measured at a mixer temperature of 125 K. An analysis and engineering equations are given for receiver noise components, noise equivalent power, available mixer conversion gain, mixer transducer gain, and quantum-noise factor in terms of such factors as mixer parameters, quantum efficiency, mixer temperature, dynamic conductance, bias voltage, local oscillator power, and i.f. amplifier characteristics.
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  • 56
    Publication Date: 2011-08-16
    Description: Perturbations of the solar wind downstream of the moon and lying outside of the rarefaction wave that defines the diamagnetic cavity are used to define possible source regions comprised of intrinsically magnetized areas of the moon. A map of the moon is constructed showing that a model in which the sources are exposed to the grazing solar wind during the lunation yields a selenographically invariant set of regions strongly favoring the lunar highlands over the maria. An alternative model with the source due to electromagnetic induction is explored. The ages of the field sources should be consistent with those based on the basalt ages and possibly far older if the sources are connected with the formation of the highland rocks themselves. The perturbations are tentatively identified as weak shock waves, and a Mach angle in accord with nominal values for the solar wind is found.
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 77; Feb. 1
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  • 57
    Publication Date: 2011-08-16
    Description: Data from two flights of a new superconducting magnetic spectrometer are reported. This instrument was capable of a direct matter-antimatter separation in the cosmic rays. Antimatter events would appear in the spectrometer as trajectories which curve in the opposite direction to common matter, because of their negative charge. A brief description of the equipment and of the characteristics of the instrument is presented, along with the data processing techniques used. A new upper limit on the amount of antimatter in primary cosmic rays has been established. The limits are considerably lower than those for any previous experiment.
    Keywords: SPACE RADIATION
    Type: Nature; 236; Apr. 14
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  • 58
    Publication Date: 2011-08-16
    Description: The requirements for a tuned laser radar capable of detecting and ranging a high altitude barium ion cloud release are discussed. A high energy pulsed dye laser tuned to the 455.4 nm Ba II resonance line is considered as the transmitter. Photon counting detection is employed and the resultant signal is integrated over a number of successive laser firings. The solar induced radiance of the cloud is the major background noise source. Detection and ranging may be achieved with signal-to-noise ratios of the order of unity using currently available equipment. This technique has the potential of improved resolution as compared to photographic measurements previously made.
    Keywords: COMMUNICATIONS
    Type: Planetary and Space Science; 20; Mar. 197
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  • 59
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    Publication Date: 2011-08-16
    Description: Single-sideband phase modulation (SSBPM), in which a signal is simultaneously phase- and amplitude-modulated by a signal and its Hilbert transform, is shown to be suboptimum for binary signaling in white Gaussian noise. An alternative single-sideband technique based on the properties of binary suppressed-carrier phase modulation is proposed and shown to give performance equivalent to the double-sideband version.
    Keywords: COMMUNICATIONS
    Type: IEEE Transactions on Information Theory; IT-18; Jan. 197
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  • 60
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    Publication Date: 2011-08-16
    Description: The mechanism proposed involves the occurrence of a flare in a region of high magnetic field on the surface of a star. The flare produces oscillations in the magnetic field structure. The oscillations lead to heating of the plasma in a flux tube which emits thermal radiation. The heating may be caused by magnetic pumping or particles accelerated in periodic bursts by the flare. Synchrotron radiation from high energy particles accounts for the hard X-ray emission.
    Keywords: SPACE RADIATION
    Type: Nature; 235; Jan. 14
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  • 61
    Publication Date: 2011-08-16
    Description: An extensive set of curves for the aperture admittance of a waveguide-fed axial slot on a coated metal cylinder is presented for both an underdense plasma and a Teflon coating. Examination of these curves shows that a slot on a cylinder with a Ka of 2 to 3 has about the same aperture admittance as the identical slot opening onto a flat ground plane.
    Keywords: COMMUNICATIONS
    Type: IEEE Transactions on Antennas and Propagation; AP-20; Jan. 197
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  • 62
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    Publication Date: 2011-08-16
    Description: The model involves an assessment of the effect of beaming as indicated by the pulsations themselves rather than by assuming gamma-ray absorption by interaction with an isotropic photon field. The chief absorption process to be taken into account is that of pair production in the intense photon field. Most important is the pair production in the intense photon field which occurs during the pulse.
    Keywords: SPACE RADIATION
    Type: Nature Physical Science; 235; Jan. 3
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  • 63
    Publication Date: 2011-08-16
    Description: Results of observations of the solar eclipse of Mar. 7, 1970, with photometers sensitive to narrow bands of radiation at Lyman-alpha (1216 A) and at 2600 A included in the payloads of four Nike Apache rockets flown before and during the eclipse. At the center of totality, the flux of Lyman-alpha from the solar corona is 0.15% of the flux from the unobscured sun. The flux at second contact is 0.64%; at third contact, two observations give 0.52 and 0.59%. The brightness of the chromosphere in Lyman-alpha decreases exponentially over the range from 5 to 30 arc-sec from the limb with a scale height of 3835 plus or minus 70 km. In addition to the coronal and chromospheric Lyman-alpha a diffuse source is found. This is restricted to within 20 deg of the earth's horizon and is nearly uniform in azimuth at 170 km, the flux is about 3% of that from the unobscured sun. The flux of Lyman-alpha during the eclipse is considered in relation to the observed variation in electron density. It is concluded that, in totality, the ionosphere near 80 km is not in equilibrium with the ionizing radiation and that the production rate for electrons is not negligible if the loss process is recombination; it is negligible if the loss process is attachment-like.
    Keywords: SPACE RADIATION
    Type: Journal of Atmospheric and Terrestrial Physics; 34; Apr. 197
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  • 64
    Publication Date: 2011-08-16
    Description: Measurement of the absorption profiles and residual fluxes of three bands of solar X-rays before and during the eclipse of Mar. 7, 1970. In the bands 2 to 8 A, 8 to 20 A, and 44 to 60 A the residual flux in totality is found to be respectively 5, 7, and 16% of the flux from the uneclipsed sun. It is shown that the radiation maintaining the E-layer varies in proportion to the 44- to 60-A flux. In the D-layer, ionization by the residual flux of 2 to 8 A is less important in totality than is ionization of nitric oxide by Lyman-alpha.
    Keywords: SPACE RADIATION
    Type: Journal of Atmospheric and Terrestrial Physics; 34; Apr. 197
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  • 65
    Publication Date: 2011-08-16
    Description: Measurement of the charge composition for several of the multicharged nuclei and the energy spectra for hydrogen, helium, and medium (6 less than or equal to Z less than or equal to 9) nuclei in the Apr. 12, 1969, solar-particle event. The energy/nucleon spectral shape of the medium nuclei was again the same as that of the helium nuclei, and the ratio of these two species was consistent with the present best average of 58 plus or minus 5. By combining the results obtained here with previous work, improved estimates of the Ne/O and Mg/O values of 0.16 plus or minus 0.03 and 0.056 plus or minus 0.014, respectively, were obtained. Silicon and sulfur abundances relative to O were determined to be 0.208 plus or minus 0.008 plus or minus 0.006, respectively, and 85% confidence upper limits for Ar and Ca relative to O of 0.017 and 0.010 were obtained. Previously, these last four nuclei had only been listed as a group.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 171; Jan. 1
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  • 66
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    Publication Date: 2011-08-16
    Description: Determination of a relation for the detector-aperture size for spatially coherent detection when dependent scattering is present. This relation is applied to several realistic laser-radar situations. It is concluded that no distortion of laser-radar signal signatures due to spatial-detection effects should be expected for present typical operating conditions (i.e., mean wavelength of the source = 0.6943 micrometer, and the diameter of the receiving aperture is about 10 cm). With development of longer-wavelength laser radars, in order to monitor signal returns at pollutant-gas absorption lines concomitantly larger receiver apertures must be used or else widely varying signal signatures will result even though similar conditions prevail.
    Keywords: COMMUNICATIONS
    Type: Optical Society of America; vol. 62
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  • 67
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    Publication Date: 2011-08-16
    Description: An X-ray imaging system using a pin-hole camera and a position sensitive proportional counter at the image plane has been designed for an all-sky X-ray monitor for UK-5 satellite. This high-sensitivity device with real-time coverage of the entire celestial sphere would aid in programming satellite maneuvers such that transient events in the X-ray sky could be investigated in detail by the other primary satellite experiments. Discussion of design criteria for the camera geometry, the position sensitive proportional detector, and electronics to handle the data is presented in this paper.
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  • 68
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    Publication Date: 2011-08-16
    Description: The scattering of electromagnetic waves by arbitrarily oriented, infinitely long circular cylinders is solved by following the procedures outlined by van de Hulst. The far-field intensities for two cases of a linearly polarized incident wave are derived. The scattering coefficients involve the Bessel functions of the first kind, the Hankel functions of the second kind, and their first derivatives. Calculations are made for ice cylinders at three wavelengths: 0.7, 3, and 10 microns. The numerical results of intensity coefficients are presented as functions of the observation angle. A significant cross-polarized component for the scattered field, which vanishes only at normal incidence, is obtained. It is also shown that the numerous interference maxima and minima of the intensity coefficients due to single-particle effects depend on the size parameter as well as on the oblique incident angle.
    Keywords: COMMUNICATIONS
    Type: Applied Optics; 11; Mar. 197
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  • 69
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    Publication Date: 2011-08-16
    Description: A simple formula useful for predicting leakage through a circular hole array in a metallic flat plate is presented. A correction is given for plate thickness. The formula is applicable to arrays having either a 60-deg (staggered) or 90-deg (square) hole pattern, but is restricted to the case of (1) an obliquely incident plane wave with the E field polarized normal to the plane of incidence, and (2) large transmission loss. When theoretical values were compared to experimental data obtained on test samples having transmission losses greater than 20 dB, the agreement between theory and experiment was typically better than 1 dB at S band and 2 dB at X band.
    Keywords: COMMUNICATIONS
    Type: IEEE Transactions on Microwave Theory and Techniques; MTT-20; Mar. 197
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  • 70
    Publication Date: 2011-08-16
    Description: A procedure is given for deriving elevation-error and range-error correction equations in a form suitable for use in the rapid processing of satellite tracking data. The refractivity of the troposphere is assumed to have spherical symmetry, but may have any given profile that does not depart greatly from standard. When the procedure was tested for numerical accuracy by application to an exponential profile, the corrections calculated agreed with those obtained by ray tracing to 0.3% or better over a range of surface refractivity from 200 to 450 and a range of radiowave arrival angles from horizontal to vertical.
    Keywords: COMMUNICATIONS
    Type: Radio Science; 7; Feb. 197
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  • 71
    Publication Date: 2011-08-16
    Description: Detailed examination of the intensity variations of 3- to 12-MeV interplanetary electrons. The data are from the Goddard cosmic-ray experiment on the Imp satellites and cover the period from just before the last solar minimum through the onset of the present solar maximum (i.e., from December 1963 through August 1969). A morphology for the intensity changes is tentatively proposed that includes solar-flare-associated events, solar co-rotating increases, Forbush decreases, quiet-time increases, and the long-term 11-year variation. It is contended that the electron components observed both during quiescent times and during quiet-time increases are galactic in origin. The quiet-time increases represent a completely new phenomenon that appears to be unique to the low-energy electron population. During a quiet-time increase the electron intensity is enhanced by a factor of 3 to 5 over a period of days, and, in general, these periods anticorrelate with low-energy solar particle events. Qualitatively, their amplitude diminishes with increasing solar activity.
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 77; May 1
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  • 72
    Publication Date: 2011-08-16
    Description: Discussion of a possible explanation for the increases in the intensity range of 3- to 12-MeV interplanetary electrons that McDonald et al. (1972) have labeled as 'quiet-time electron increases.' It is argued that the electrons in quiet-time increases are galactic in origin but that the observed increases are not the result of any variation in the modulation of these particles in the inner solar system. It is suggested instead that quiet-time increases may occur when more electrons than normal penetrate a modulating region that lies far beyond the orbit of the earth. The number of electrons penetrating this region may increase when field lines that have experienced an unusually large random walk in the photosphere are carried by the solar wind out to the region. As evidence of this increased random walk, it is shown that five solar rotations before most of the quiet-time increases occur there is an extended period when the amplitude of the diurnal anisotropy (measured by the Deep River neutron monitor) is relatively low. A delay time of five rotations implies that the proposed modulating region lies at about 30 AU from the sun if the average solar-wind speed is assumed to be constant at about 400 km/sec over this distance. The implications for the correlation between periods of low-amplitude diurnal anisotropy and quiet-time increases on interplanetary conditions out to about 30 AU and some possible models for the proposed modulating region are also considered.
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 77; May 1
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  • 73
    Publication Date: 2011-08-16
    Description: A model for predicting the atmospheric effect for earth-to-orbit range or range-rate measurements is described. The model treats the dry and wet components of refractivity (N) as different functions of its surface value and of height above the earth. It provides a zenith integral of the dry component that is consistent with the equation for the zenith range effect in dry air. For low angle use, it gives a reasonable approximation of observed N profiles. The use of the model is discussed, and data and computed positions without and with a correction for the troposphere are presented.
    Keywords: COMMUNICATIONS
    Type: APL Technical Digest; 11; Mar
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  • 74
    Publication Date: 2011-08-16
    Keywords: SPACE RADIATION
    Type: Astrophysics and Space Science; 16; May 1972
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  • 75
    Publication Date: 2011-08-16
    Keywords: SPACE RADIATION
    Type: Nature Physical Science; 239; Oct. 23
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  • 76
    Publication Date: 2011-08-16
    Keywords: SPACE RADIATION
    Type: Astronomical Society of the Pacific; vol. 84
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  • 77
    Publication Date: 2011-08-16
    Description: The main characteristics of free oscillations of the sun are described, and the sources and sinks of energy are estimated. Adiabatic oscillations and damping are considered. It is shown how a large solar flare can exert a significant mechanical impulse on the sun by causing a wave of compression to move subsonically into the interior. The solar interior does not easily dissipate low-amplitude acoustical energy, and therefore a relatively large fraction of the energy should remain available to go into the normal modes. An estimate is made of how this energy might be distributed among the more interesting modes.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 176; Sept. 15
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  • 78
    Publication Date: 2011-08-16
    Description: Position and intensity measurements made with proportional counters in the 2 to 12 keV band are described. The instruments were launched from Johnson Atoll, and four scans were carried out during the 525 sec spent above 200 km. In comparing the results with the Uhuru survey, only a few differences are noted. One variable source, 2U 1908+0, was weaker. The case of the Magellanic Cloud sources is discussed.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 176; Sept. 15
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  • 79
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    Publication Date: 2011-08-16
    Description: An upper limit is presented for the torque exerted on the earth by the solar wind. It is found that the maximum possible torque is 3 or 4 orders of magnitude too small to be responsible for the slowing of the earth's rotation, contrary to Coleman's (1971) suggestion.
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 77; Sept. 1
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  • 80
    Publication Date: 2011-08-16
    Description: Review of the solar-wind disturbance models proposed by Piddington (1958), Gold (1959, 1962), Parker (1961), and De Young and Hundhausen (1971), in an attempt to determine what information and conclusions can be drawn about these models by examining the interplanetary magnetic field. The conclusions reached suggest that little, if any, flux is permanently ejected during the average solar-wind disturbance.
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 77; Sept. 1
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  • 81
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    Publication Date: 2011-08-16
    Description: Solar flares which produce relativistic electrons generally occur within sunspot groups which are active in the emission of meter type I noise storms. It is suggested that relativistic electrons in solar flares are accelerated from the keV-energy electrons responsible for the type I noise storms. The relationship between flare developments and the ejection of keV-electrons is briefly considered.
    Keywords: SPACE RADIATION
    Type: Planetary and Space Science; 20; Aug. 197
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  • 82
    Publication Date: 2011-08-16
    Description: A scintillation counter telescope consisting of eight liquid scintillation counters and four wide-gap spark chambers was used to search for particles with electric charge 1/3e and 2/3e in cosmic rays at 2750 m above sea level. No such particles were detected during the 1500-hr experimental run. Upper limits on the vertical fluxes are established, and estimates of the corresponding sea-level fluxes are made for comparison with previous results.
    Keywords: SPACE RADIATION
    Type: Physical Review D - Particles and Fields; vol. 6
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  • 83
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    Publication Date: 2011-08-16
    Description: The difference in objectives, physical assumptions, and results among the most recent detailed models aimed at understanding energy transport in the solar wind are analyzed. Models have been judged primarily by comparing their predictions against spacecraft observations near 1 AU. However, the observed values of flow speed, density, and temperature fluctuate over a wide range so that the criteria for agreement between theory and observation are necessarily somewhat subjective.
    Keywords: SPACE RADIATION
    Type: Cosmic Electrodynamics; 3; July 197
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  • 84
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    In:  Other Sources
    Publication Date: 2011-08-16
    Description: Rocket experiments were conducted to collect particles from noctilucent clouds at Kiruna, Sweden. The Pandora II inflight shadowing technique considered by Hallgren and Hemenway (1971) was used in the experiments. This technique makes it possible to study the collected particles as a function of time and altitude intervals. The particles observed consisted of an irregular electron-opaque core surrounded by a rounded, low density material. X-ray and electron opacity data suggest that the abundances of the heavy elements, such as Hf and Ta, in the particles are comparable to those of the light elements, such as Al and Si.
    Keywords: SPACE RADIATION
    Type: Nature; 238; Aug. 4
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  • 85
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    In:  Other Sources
    Publication Date: 2011-08-16
    Description: Use of observations of the solar wind by Explorers 34 and 43 to confirm the existence of a linear relationship between the relative abundance of helium and the bulk speed of the wind, recently described by Hirshberg et al. (1972). Use of this relationship allows the dependence of the relative abundance of helium on solar activity to be separated from its dependence on bulk speed. The proportion of helium in the solar wind at a given bulk speed is found to increase with increasing sunspot number, averaged over the period of observation. It is shown that the relationship between average relative abundance and temperature, deduced by using the bulk speed/temperature relation, is consistent with the data. The relative abundance of helium is not found to increase with increasing solar-wind flux. This confirms the result of Hirshberg et al.
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 77; Aug. 1
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  • 86
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    In:  Other Sources
    Publication Date: 2011-08-16
    Description: Calculation of the X-ray interaction cross sections for three cosmic mixtures over the range from 1 keV (12.4 A) to 1.5 MeV (0.008 A). The cosmic composition of elements as given by Aller and utilized by Bell and Kingston (1967) and the total photon interaction cross sections per atom of the elements as computed by Hubbell and collaborators are used for this purpose. The results are compared with a formula given by Heiles (1971). Approximate agreement exists between 10 to 20 keV.
    Keywords: SPACE RADIATION
    Type: Journal of Applied Physics; 43; Aug. 197
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  • 87
    Publication Date: 2011-08-16
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 77; July 1
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  • 88
    Publication Date: 2011-08-16
    Description: The causes of the variations in the relative abundance of helium in the solar wind are not understood. To define the theoretical problem more precisely, empirical relationships between helium abundances and other pertinent solar-wind parameters are necessary. In this report we show that the average percentage of helium increases with the solar-wind velocity. We also confirm that the abundance of helium tends to be higher for low solar-wind fluxes rather than lower as expected from theory. The interpretation of these results is discussed, and it is concluded that more realistic theoretical treatments of the problem are necessary before these results can be understood in terms of models of the solar corona and solar wind.
    Keywords: SPACE RADIATION
    Type: Journal of Geophysical Research; 77; July 1
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  • 89
    Publication Date: 2011-08-16
    Description: A search was made for a diffuse component of greater than 1.5 keV X rays associated with an interarm region of the Galaxy at galactic longitudes in the vicinity of 60 degrees. A statistically significant excess associated with a narrow disk component was detected. The angular extent of this component has a most probable value of 2 degrees. The best-fit spectrum yields an intensity of 2.9 photons/sq cm per sec per sterad over the 2-10 keV range. The 3-sigma upper limit to any emission in a 1.5 keV band centered at 7 keV from galactic latitudes not greater than 3.5 deg is 0.3 photons/sq cm per sec per sterad. Several possible emission models are evaluated, with the most likely choice being a population of unresolvable low-luminosity sources.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 174; June 1
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  • 90
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    In:  Other Sources
    Publication Date: 2011-08-16
    Description: It is shown that transition radiation generated during the passage of relativistic charged particles through interstellar grains can be an important source of cosmic X-rays. In order to account for recent X-ray observations below 300 eV by transition radiation, an energy density in interstellar space of about 10 eV per cu cm in 10 MeV electrons is required. This seems to rule out transition radiation as an important source of diffuse cosmic X-rays in any energy region.
    Keywords: SPACE RADIATION
    Type: Astrophysical Letters; 11; May 1972
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  • 91
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    In:  Other Sources
    Publication Date: 2011-08-16
    Description: An exact mathematical model is developed for a discrete loop of a general order particularly suitable for digital computation. The deterministic response of the loop to the phase step and the frequency step is investigated. The design of the digital filter for the second-order loop is considered. Use is made of the incremental phase plane to study the phase error behavior of the loop. The model of the noisy loop is derived and the optimization of the loop filter for minimum mean-square error is considered.
    Keywords: COMMUNICATIONS
    Type: IEEE Transactions on Aerospace and Electronic Systems; AES-8; Sept
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  • 92
    Publication Date: 2011-08-16
    Description: Satellite observations of traveling solar radio bursts provide information about the propagation of energetic solar particles through interplanetary space. This information leads to data on the solar wind density and gross magnetic field configuration over distances of 1 AU. By placing a radio telescope well above the ionosphere it is possible to observe the radio emission down to frequencies that correspond to emission at distances of the order of 1 AU. The observations reported provide the first 'radio picture' over 1 AU of the spiral magnetic field configuration in interplanetary space.
    Keywords: SPACE RADIATION
    Type: Science; 178; Nov. 17
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  • 93
    Publication Date: 2011-08-16
    Description: Simultaneous measurements of radar reflectivity and radio refractive index at several altitudes in clear air convection have been made. The experimental data were compared with the theoretical relationship which relates the reflectivity to the refractivity spectrum. The agreement between the measurements and the theory is excellent and shows that the radar returns in clear air are the result of, and can be quantitatively described as being from, fine-scale refractivity fluctuations due to turbulent mixing. Further, the data give strong support to the -5/3 spectral decay of the refractivity spectrum in the inertial subrange.
    Keywords: COMMUNICATIONS
    Type: Journal of Applied Meteorology; 11; Oct. 197
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  • 94
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    Publication Date: 2011-08-16
    Keywords: COMMUNICATIONS
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  • 95
    Publication Date: 2011-08-16
    Keywords: COMMUNICATIONS
    Type: IEEE Transactions on Communications; COM-20; Oct. 197
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  • 96
    Publication Date: 2011-08-16
    Description: It is shown that the production of small nitrogen to carbon ratios is possible, in contrast to the equilibrium production in the ordinary CN cycle. Associated with such a production are high ratios of C-13/C-12 and of N-15/N-14. The final ratios depend on the conditions under which cessation of hydrogen burning occurs under astrophysical circumstances. A table showing proton capture mean lifetimes of CN nuclei is provided together with tables of the equilibrium abundances in a fast CN cycle. The ratios of final abundances of nitrogen to carbon as functions of temperature are also presented.
    Keywords: SPACE RADIATION
    Type: Nature Physical Science; 238; July 10
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  • 97
    Publication Date: 2011-08-16
    Keywords: SPACE RADIATION
    Type: Space Science Reviews; 13; May 1972
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  • 98
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    In:  Other Sources
    Publication Date: 2011-08-16
    Description: Abstract missing.
    Keywords: SPACE RADIATION
    Type: Solar Physics; 23; Mar. 197
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  • 99
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    In:  Other Sources
    Publication Date: 2011-08-16
    Description: The extended X-ray sources associated with the Virgo, Perseus, and Coma clusters of galaxies can best be explained as a result of the Compton scattering of relativistic electrons (generated in the radio sources which are present in each of these clusters) on the microwave background radiation. The same physical process involving microwave infrared or optical photons generated in the nuclei of active galaxies may account for the more compact X-ray sources. Thermal bremsstrahlung of hot gas in clusters of galaxies is a less likely source of X-rays.
    Keywords: SPACE RADIATION
    Type: Nature; 237; June 23
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  • 100
    Publication Date: 2011-08-16
    Description: A Monte Carlo technique involving Stokes vectors is used to obtain the state of polarization and intensity of solar Lyman-alpha photons as they diffuse through a plane-parallel homogeneous model of earth's hydrogen envelope. Fine structure of Lyman-alpha and Doppler redistribution of frequencies are taken into account. Comparison of the results with Heath's observed upper limit for polarization of 1.5 per cent implies an optical thickness tau greater than 7 and intensities of 8-10 kilorayleighs for a solar Lyman-alpha flux of 5.8 ergs per sq cm per sec.
    Keywords: SPACE RADIATION
    Type: Astrophysical Journal; 175; July 1
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