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  • Other Sources  (412)
  • SOLAR PHYSICS  (252)
  • NONMETALLIC MATERIALS  (160)
  • 1980-1984  (412)
  • 1950-1954
  • 1982  (412)
  • 1
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    Shuttle tile environments and loads (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The Shuttle tile ascent environments are discussed and the procedures used to convert these environments into tile loads are outlined. Testing which was performed to quantify or verify the loads are discussed, along with the load combination rationale which was used. The discussion of the ascent environment is limited to the transonic/supersonic portion of the mission since mechanical design loads occur during this time, and to specific regions of the vehicle, in particular those regions in which undensified critical (black) tiles are located.
    Keywords: NONMETALLIC MATERIALS
    Type: Shock and Vibration Inform. Center The Shock and Vibration Bull., No. 52. Part 2; p 111-125
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  • 2
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    Structural characteristics of the shuttle orbiter ceramic thermal protection system (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The thermal protection system (TPS) of the Space Shuttle Orbiter is described as well as the results of dynamic reponse studies conducted in support of the efforts to certify the TPS for flight. The ceramic Thermal Protection System consists of ceramic tiles bonded to felt pads which are in turn bonded to the Orbiter substructure to protect the aluminum substructure from the heat of reentry.
    Keywords: NONMETALLIC MATERIALS
    Type: Shock and Vibration Inform. Center The Shock and Vibration Bull., No. 52. Part 2; p 101-110
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  • 3
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    Fibrous ceramic insulation (1982)
    In:  CASI
    Details
    Publication Date: 2006-04-12
    Description: Some of the reusable heat shielding materials used to protect the Space Shuttles, their manufacturing processes, properties, and applications are discussed. Emphases is upon ceramic materials. Space Shuttle Orbiter tiles are discussed.
    Keywords: NONMETALLIC MATERIALS
    Type: NASA. Langley Research Center Advan. Mater. Technol.; p 261-274
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  • 4
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    Polymer research at NASA Langley Research Center (1982)
    In:  CASI
    Details
    Publication Date: 2006-04-12
    Description: Polymer synthesis programs involve the development of Novel thermoplastics, pseudothermoplastics, and thermosets. These systems are prepared to elucidate structure-property relationships involving thermal capabilities, toughness, processability and environmental stability. Easily processable polyimides, solvent-resistant polysulfones and polyphenylquinoxalines, and tougher high and intermediate temperature polymers were developed. Characterization efforts included high pressure liquid chromatography methodology, the development of toughness tests for fiber reinforced composites, a study of electrical properties of metal ion filled polyimides, and a study of the mutagenicity of aromatic diamines. Also the mechanism of cure/degradation of experimental polymers was studied by rheology, mechanical behavior, separation techniques and spectroscopy. The degradative crosslinking of alkyl-containing polyimides, the separation and identification of crosslinked phenylquinoxalines, the rheological behavior of hot-melt polyimides, and the elucidation of the cure of norbornene endcapped imides were also studied.
    Keywords: NONMETALLIC MATERIALS
    Type: Advan. Mater. Technol.; p 29-48
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  • 5
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    Polymer materials research at NASA Ames Research Center (1982)
    In:  CASI
    Details
    Publication Date: 2006-04-12
    Description: Polymers that provide significant improvements in both efficiency and safety for civilian transport aircraft and military combat aircraft were developed. High strength to weight structures such as carbon fiber composites with long term durability are requirements common to both classes of aircraft. Aircraft safety improvements in fire resistance and crashworthiness of primary and secondary structures are long term objectives for transport aircraft. Void filler ballistic foams, intumescent coatings, and radiation-resistant transparent plastics contribute to vulnerability reduction in combat military aircraft. Low and high velocity impact tolerance, fire resistance, thermal stability, and long term durability of polymers and components are emphasized.
    Keywords: NONMETALLIC MATERIALS
    Type: NASA. Langley Research Center Advan. Mater. Technol.; p 49-64
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  • 6
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    Synthesis of aminosilane and aromatic diamine intermediates for polymerization (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: The preparation of monomers for use in a study to improve properties of epoxy polymers and silicone elastomers is described. Various approaches to the solution of the synthesis of aminosilane and diamine curing agents were examined. Ortho-, meta-, and para-substituted diamines where X is CH2, C(CH3)2, O, S, NH, or SO2 and n = 0, 1, 2, and 3 were investigated.
    Keywords: NONMETALLIC MATERIALS
    Type: The 1981 NASA(ASEE Summer Fac. Fellowship Program; 9 p
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  • 7
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    Development of high strength, high temperature ceramics (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: Improvement in the high-pressure turbopumps, both fuel and oxidizer, in the Space Shuttle main engine were considered. The operation of these pumps is limited by temperature restrictions of the metallic components used in these pumps. Ceramic materials that retain strength at high temperatures and appear to be promising candidates for use as turbine blades and impellers are discussed. These high strength materials are sensitive to many related processing parameters such as impurities, sintering aids, reaction aids, particle size, processing temperature, and post thermal treatment. The specific objectives of the study were to: (1) identify and define the processing parameters that affect the properties of Si3N4 ceramic materials, (2) design and assembly equipment required for processing high strength ceramics, (3) design and assemble test apparatus for evaluating the high temperature properties of Si3N4, and (4) conduct a research program of manufacturing and evaluating Si3N4 materials as applicable to rocket engine applications.
    Keywords: NONMETALLIC MATERIALS
    Type: Alabama Univ. in Huntsville The 1981 NASA(ASEE Summer Fac. Fellowship Program; 11 p
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  • 8
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    Development of toughened epoxy polymers for high performance composite and ablative applications (1982)
    In:  CASI
    Details
    Publication Date: 2006-02-14
    Description: A survey of current procedures for the assessment of state of cure in epoxy polymers and for the evaluation of polymer toughness as related to nature of the crosslinking agent was made to facilitate a cause-effect study of the chemical modification of epoxy polymers. Various conformations of sample morphology were examined to identify testing variables and to establish optimum conditions for the selected physical test methods. Dynamic viscoelasticity testing was examined in conjunction with chemical analyses to allow observation of the extent of the curing reaction with size of the crosslinking agent the primary variable. Specifically the aims of the project were twofold: (1) to consider the experimental variables associated with development of "extent of cure" analysis, and (2) to assess methodology of fracture energy determination and to prescribe a meaningful and reproducible procedure. The following is separated into two categories for ease of presentation.
    Keywords: NONMETALLIC MATERIALS
    Type: Alabama Univ. in Huntsville The 1981 NASA(ASEE Summer Fac. Fellowship Program; 17 p
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  • 9
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    Polymer matrix composites research at NASA Lewis Research Center (1982)
    In:  CASI
    Details
    Publication Date: 2006-04-12
    Description: The in situ polymerization of monomer reactants (PMR) approach was demonstrated to be a powerful approach for solving many of the processing difficulties associated with the use of high temperature resistant polymers as matrix resins in high performance composites. The PMR-15 polyimide provides the best overall balance of processing characteristics and elevated temperature properties. The excellent properties and commercial availability of composite materials based on PMR-15 led to their acceptance as viable engineering materials. The PMR-15 composites are used to produce a variety of high quality structural components.
    Keywords: NONMETALLIC MATERIALS
    Type: NASA. Langley Research Center Advan. Mater. Technol.; p 65-90
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  • 10
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    Corrosion protection coating (1982)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: NONMETALLIC MATERIALS
    Type: NASA Technol. Appl. Team; p 40
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  • 11
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    Ion beam deposition of amorphous carbon films with diamond like properties (1982)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Description: Carbon films were deposited on silicon, quartz, and potassium bromide substrates from an ion beam. Growth rates were approximately 0.3 micron/hour. The films were featureless and amorphous and contained only carbon and hydrogen in significant amounts. The density and carbon/hydrogen ratio indicate the film is a hydrogen deficient polymer. One possible structure, consistent with the data, is a random network of methylene linkages and tetrahedrally coordinated carbon atoms.
    Keywords: NONMETALLIC MATERIALS
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  • 12
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    Energetic electrons associated with solar radio storms (1982)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: SOLAR PHYSICS
    Type: Osservatorio Astronomico Solar Radio Storms. Proc. of the 4th CESRA Workshop on Solar Noise Storms; p 320-323
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  • 13
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    Solar radio storms in the hectometer-kilometer wavelength range (1982)
    In:  Other Sources
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    Publication Date: 2011-08-19
    Keywords: SOLAR PHYSICS
    Type: Osservatorio Astronomico Solar Radio Storms. Proc. of the 4th CESRA Workshop on Solar Noise Storms; p 70-88
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  • 14
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    Solar variability (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The variability in the total radiant energy flux, or solar irradiance, is discussed. Direct techniques of measuring irradiance, including ground-based, balloon and rocket-borne, and spacecraft-based measurements are compared; the latter type has led to dramatic advances in accuracy since it eliminates the need for corrections for atmospheric absorption. Correlations of the measured irradiance with solar activity are described. Indirect techniques that monitor other solar parameters such as photospheric conditions or the solar diameter are reviewed, and theoretical studies which attempt to interpret the measurements are discussed. Physical mechanisms which can lead to changes in the solar luminosity are addressed, as is global time-dependent modeling of the response of the sun to structural perturbations. Finally, findings from all techniques are summarized, their weak and strong points are assessed, and suggestions for future research are made.
    Keywords: SOLAR PHYSICS
    Type: Comments on Modern Physics; vol. 9
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  • 15
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    Morphological and frictional behavior of sputtered MoS2 films (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-22387)
    Keywords: NONMETALLIC MATERIALS
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  • 16
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    Measurement of the rugged invariants of magnetohydrodynamic turbulence in the solar wind (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Measurements of the total energy, cross helicity, and magnetic helicity of the solar wind at 1, 2.8, and 5 AU are presented. These quantities are the three rugged invariants of three-dimensional ideal incompressible MHD turbulence theory. The theoretical technique for measuring the magnetic helicity from the matrix of two-point correlations is shown. The length scales characterizing the magnetic helicity are found to be equal to or greater than those which characterize the magnetic energy. The magnetic helicity typically lies at scales larger than the magnetic correlation length, consistent with the expectations of the inverse cascade and selective decay hypotheses of three-dimensional MHD turbulence. At smaller scales, the magnetic helicity oscillates in sign. Measurements of the cross helicity are not fully consistent with the usual interpretation in terms of outward propagating Alfvenic functions. Especially during the interval at 5 AU the cross helicity is found to oscillate in sign indicating fluctuations propagating both outward and inward.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 87; Aug. 1
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  • 17
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    Type II solar radio events observed in the interplanetary medium. I - General characteristics (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N81-15927)
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 78; May 1982
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  • 18
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    S IV emission-line ratios in the sun (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: New atomic data are presented for transitions between the five lowest levels in S IV, taking into account the fine-structure rates between the individual J levels together with the electron impact mixing rates within the levels. The values are found to differ significantly from previously published values. Using the atomic data, ionic level populations are deduced for a range of electron temperatures and densities. The results are used to calculate theoretical line intensity ratios for S IV. Excellent agreement is found with intensity ratios for a variety of solar features observed with the NRL normal incidence spectrograph on Skylab.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 257
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  • 19
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    Solar irradiance variations due to active regions (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Questions regarding changes in solar irradiance due to activity are important, since such changes may have a significant effect on the earth's climate. Solar irradiance measurements conducted outside the earth's atmosphere and, therefore, not affected by it have become possible by utilizing for such measurements satellites, such as the Nimbus 7 and the Solar Maximum Mission satellite (ACRIM experiment). The present investigation has the objective to show that a combination of sunspots and faculae is capable of representing the observed variations in the values of ACRIM data to a satisfactory degree, given the current level of uncertainties in the ground-based data.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 256
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  • 20
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    Radial variation of the solar wind speed between 1 and 15 AU (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Pioneer 10 and 11 solar wind speeds measured between 1.4 and 15.2 AU are compared with those of IMP 6, 7, and 8 measured at 1 AU for 90-day intervals centered on six solar radial alignments between 1973 and 1978. The time profile of the solar wind speed undergoes change as the distance from the sun increases, which is due to interaction of adjacent solar wind streams. Speed variations are smaller at greater radial distance and both the highest and lowest speeds disappear as radial distance increases. For periods with extremely high speed solar wind streams, the mean solar wind speed decreases as the distance from the sun increases, which must be due to the disappearance of the highest speeds of the streams with increasing distance. It is concluded that at distances from the sun greater than 30-40 AU, the solar wind behavior may closely resemble that of a radially expanding constant speed plasma.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 87; Apr. 1
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  • 21
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    Measurement of the profile of solar He I resonance lines (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The analysis of data obtained by a rocket-borne helium-filled spectrometer employing a curve-of-growth technique in 1977 and 1980 is used in an investigation of the 584-A helium resonance line from the full solar disk. Between 6.5 and 13% of the Gaussian core area was found to be missing through self-reversal. Line widths from 1980 and 1977 were 101 + or - 10 mA and 128 + or - 20 mA full width at half maximum, respectively. No consistent relationship is found between the measured widths and solar activity.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 87; Mar. 1
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  • 22
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    Fluid motions the solar chromosphere-corona transition region. II Active region flows in C IV from narrow slit Dopplergrams (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 261
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  • 23
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    Performance of laser-glazed zirconia thermal barrier coatings in cyclic oxidation and corrosion burner rig tests (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-22346)
    Keywords: NONMETALLIC MATERIALS
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  • 24
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    Some properties of r.f.-sputtered hafnium nitride coatings (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-21331)
    Keywords: NONMETALLIC MATERIALS
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  • 25
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    Sputtered silicon nitride coatings for wear protection (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-20314)
    Keywords: NONMETALLIC MATERIALS
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  • 26
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    The combined effects of Fe and H2 on the nitridation of silicon (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: In view of the support offered by previous work for the suggestion that Fe may affect alpha-Si3N4 formation and microstructural development, a two-part study was conducted to differentiate the effects of H2 and Fe in, first, the nitridation of pure and of Fe-containing powder in N2 and N2-4% H2, and then the nitridation of (1 1 1) Si single crystal wafers with and without Fe powder on the surface. The degree of nitridation is most strongly affected by H2 at 1200 C, but by Fe at 1375 C, where Fe-containing samples in either atmosphere were almost completely nitrided. While neither H2 nor Fe alone changed the ratio of alpha-Si3N4 to beta-Si3N4, the combination of H2 and Fe increased it at both temperatures.
    Keywords: NONMETALLIC MATERIALS
    Type: Journal of Materials Science Letters; 1; Aug. 198
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  • 27
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    Experimental studies of the vapor phase nucleation of refractory compounds. I - The condensation of SiO (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The critical partial pressure of SiO necessary to initiate avalanche nucleation in the SiO-H2 system is measured as a function of the ambient temperature in the range 750-1000 K. Results show that the condensate produced at low temperatures is Si2O3, while a mixture of Si2O3 and amorphous SiO2 is produced at high temperatures. A surface energy of approximately 500 ergs/sq cm for the particles is found by analyzing the critical partial pressure vs temperature using classical nucleation theory. It is concluded that classical nucleation theory is not applicable to this system, because several inconsistencies in the thermodynamic analysis are demonstrated, and it is suggested that a kinetic theory of nucleation may be the preferential way to describe the condensation process.
    Keywords: NONMETALLIC MATERIALS
    Type: Journal of Chemical Physics; 77; Sept. 1
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  • 28
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    Mass motions in the solar chromosphere and transition zone (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A comparison is made between H-alpha and C IV observations of Active Region 2717 on October 9, 1980. On the basis of this comparison, it is found that upward velocities are present above sunspots in the chromosphere-corona transition zone (20 km/s). The downward velocities are found to be well correlated in both lines. Doppler-shift ratios between C IV and H-alpha levels (approximately 10) are seen to be much smaller than expected from density ratio estimates. The comparison is seen as suggesting that flow lines are probably far from vertical in the transition zone. It is pointed out, however, that this depends on model densities that may not be correct. A simple method for comparing matter flows is presented. The best fit between H-alpha and C IV levels is obtained when C IV Doppler shifts are multiplied by the line intensity to the power 0.5 (approximately) in order to make allowance for density fluctuations.
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics; 111; 1, Ju; July 198
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  • 29
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    The solar spectrum of O IV, including photoexcitation by Fe IX 171.07 A (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The extreme and far ultraviolet doublet spectrum of O IV, emitted from the solar transition region, is calculated taking account of expected photo-excitation by Fe IX at the wavelength 171.07 A. Four multiplets are shown to be sensitive to such photoexcitation, of which two in particular are potentially observable and could provide an estimate of the local Fe IX radiation field.
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics; 108; 2, Ap; Apr. 198
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  • 30
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    Spatial and temporal evolution of soft and hard X-ray emission in a solar flare (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Hard X-ray burst spectrometer and imaging spectrometer data are used to study the spatial and temporal characteristics of the 3.5-30.0 keV emission in an Apr. 10, 1980 solar flare. It is found that: (1) continuous energy release is needed to sustain the increase of the emission through the flare's rising phase, before and after the impulsive phase in hard X-rays, and the release is characterized by the production of 50 million-150 million K thermal regions within the flare loop structures; (2) the observational parameters which characterize the impulsive burst indicate that it is probably associated with nonthermal processes, such as particle acceleration; and (3) the continuous energy release is associated with strong chromospheric evaporation, in view of spectral line behavior. Both particle acceleration and chromospheric evaporation stop just before flare maximum, and the subsequent evolution is probably governed by the radiative cooling of the flare plasma.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 79; July 198
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  • 31
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    The solar O III spectrum. I - Photoexcitation of EUV lines by He II Lyman-alpha (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 257
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  • 32
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    Statistical properties of MHD fluctuations associated with high-speed streams from Helios-2 observations (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-18117)
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 78; June 198
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  • 33
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    Latest rocket measurements of the solar constant (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Three rocket flights which carried a payload of absolute radiometers to measure the solar constant with an accuracy of plus or minus 0.5 per cent have been accomplished. Several of the rocket radiometers were duplicates of those aboard the Solar Maximum Mission and Nimbus spacecrafts. The values for the solar constant obtained by the rocket sensors for the three flight dates indicate an increase between the first and latter two flights approximately equivalent to the uncertainty of the measurements. The values for the solar constant for the three flights are 1367, 1372 and 1374 W/sq m.
    Keywords: SOLAR PHYSICS
    Type: Solar Energy; 28; 5, 19; 1982
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  • 34
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    Compliance calibration of the short rod chevron-notch specimen for fracture toughness testing of brittle materials (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The short rod chevron-notch specimen has the advantages of (1) crack development at the chevron tip during the early stage of test loading, and (2) convenient calculation of plane-strain fracture toughness from the maximum test load and from a calibration factor which depends only on the specimen geometry and manner of loading. For generalized application, calibration of the specimen over a range of specimen proportions and chevron-notch configurations is necessary. Such was the objective of this investigation, wherein calibration of the short rod specimen was made by means of experimental compliance measurements converted into dimensionless stress intensity factor coefficients.
    Keywords: NONMETALLIC MATERIALS
    Type: International Journal of Fracture; 18; Feb. 198
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  • 35
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    Solar irradiance variations and solar activity (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A mean value for the 1 AU total solar irradiance of 1368.2 W/sq m and a downward trend of 0.05% per year were derived from measurements by the Active Cavity Radiometer Irradiance Monitor (ACRIM) experiment on the Solar Maximum Mission during 1980. Distinct temporary solar irradiance decreases associated with solar activity maxima were observed with a series of nine dips from April to October recurring at fairly regular intervals averaging 24 days. The decreases correlate inversely with sunspot area, 2800-MHz flux, and Zurich sunspot number. Dominant periods common to the irradiance and sunspot area power spectra link the irradiance decreases to sunspot flux deficit in solar active regions. Evidence of significant total irradiance modulation by facular flux excess is cited. A persistent radiative cycle of active regions consistent with the ACRIM irradiance results and the morphology of solar active regions was found. The pattern of regularly recurrent active region maxima between April and October suggests an asymmetry in solar activity generation during this period.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 87; June 1
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  • 36
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    Solar transition region response to variations in the heating rate (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The response of a numerical model for the upper chromosphere, transition region, and corona to variations in the energy input has been examined. The numerical model solves the set of one-dimensional two-fluid hydrodynamic equations in a simple vertical magnetic flux tube. The atmosphere responds to both the increase and decrease in energy deposition by smoothly readjusting the temperature gradient and the amount of material in the region of peak radiating efficiency to radiate away energy being deposited. At no time during this readjustment is a departure from a thin laminar transition region structure seen. In addition, a time-dependent description of the nonequilibrium ionization of all of the ionization stages of oxygen has been included. This calculation is coupled with the self-consistent calculations of the dynamical variables. It is found that the nonequilibrium ionization balance calculations for both heating and cooling small loops in the quiet sun predict relative ionic abundances which differ substantially from those which would be predicted by an equilibrium calculation
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 255
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  • 37
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    Dynamics of solid dispersions in oil during the lubrication of point contacts. II - Molybdenum disulfide (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N81-20275)
    Keywords: NONMETALLIC MATERIALS
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  • 38
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    Test methodology for evaluation of fireworthy aircraft seat cushions (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Aircraft seat materials were evaluated in terms of their thermal performance. The materials were evaluated using (a) thermogravimetric analysis, (b) differential scanning calorimetry, (c) a modified NBS smoke chamber to determine the rate of mass loss and (d) the NASA T-3 apparatus to determine the thermal efficiency. In this paper, the modified NBS smoke chamber will be described in detail since it provided the most conclusive results. The NBS smoke chamber was modified to measure the weight loss of materials when exposed to a radiant heat source over the range of 2.5 to 7.5 W/cm sq. This chamber has been utilized to evaluate the thermal performance of various heat blocking layers utilized to protect the polyurethane cushioning foam used in aircraft seats. Various kinds of heat blocking layers were evaluated by monitoring the weight loss of miniature seat cushions when exposed to the radiant heat. The effectiveness of aluminized heat blocking systems was demonstrated when compared to conventional heat blocking layers such as neoprene. All heat blocking systems showed good fire protection capabilities when compared to the state-of-the-art, i.e., wool-nylon over polyurethane foam.
    Keywords: NONMETALLIC MATERIALS
    Type: Journal of Fire and Flammability; 13; Jan. 198
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  • 39
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    Doppler wavelength shifts of ultraviolet spectral lines in solar active regions (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Doppler shifts are measured for solar UV emission lines formed in the lower transition region of active regions. Doppler shifts in different regions at the same solar location, variations of Doppler shift with position of an active region on the disk, and variations of Doppler shift with time at the same solar location in the same active region were studied. Observations were made with the NRL slit spectrograph on Skylab. Excluding flare and flare-related phenomena, only redshifts are found whose magnitudes correspond to downflow velocities between about 4 and 17 km/s. Shifts are largest for lines formed between about 50,000 and 100,000 K, and are distinctly less for lines formed above 100,000 K. The shifts persist out to the limb, but not above it. There is no obvious change in redshift for lines measured at the same solar location over time intervals of about 20 minutes.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 255
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  • 40
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    Ultraviolet continuum absorption /less than about 1000 A/ above the quiet sun transition region (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Lyman continuum absorption shortward of 912 A in the quiet sun solar transition region is investigated by combining spectra obtained from the Apollo Telescope Mount experiments on Skylab. The most recent atomic data are used to compute line intensities for lines that fall on both sides of the Lyman limit. Lines of O III, O IV, O V, and S IV are considered. The computed intensity ratios of most lines from O IV, O V, and S IV agree with the experimental ratios to within a factor of 2. However, the discrepancies show no apparent wavelength dependence. From this fact, it is concluded that at least part of the discrepancy between theory and observation for lines of these ions can be accounted for by uncertainties in instrumental calibration and atomic data. However, difficulties remain in reconciling observation and theory, particularly for lines of O III, and one line of S IV. The other recent results of Schmahl and Orrall (1979) are also discussed in terms of newer atomic data.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 254
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  • 41
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    The condensational instability in the solar transition region and corona (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The stability of plasmas at temperatures and densities typical of the solar transition region and corona is investigated using both a linear analysis and nonlinear time-dependent numerical simulations. Growth rates, decay rates, and oscillation frequencies of the perturbations determined from the linear analysis are in excellent agreement with the simulations. The nonlinear regime is characterized by a bifurcation of the plasma into a cool dense condensation surrounded by a hot tenuous corona. The condensation may then be accelerated by forces in the plasma such as those arising from gravity or differential heating. Finally, the results of the detailed simulation show that the transition region is a dynamically stable structure which is the result of the nonlinear evolution of the condensational instability.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 254
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  • 42
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    Transition region oscillations in sunspots (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Time series observations of the profile of the C IV resonance line 1548.19 A obtained in eight sunspots with the Ultraviolet Spectrometer and Polarimeter (UVSP) on the Solar Maximum Mission are discussed. All of the sunspots exhibit significant oscillations in line-of-sight velocity with frequencies in the range from 5.8 mHz to 7.8 mHz (periods of 129-173 s). Significant intensity oscillations are observed at the same periods in four of the time series; the maximum intensity is in phase with maximum blueshift. Difference spectroheliograms ('Dopplergrams') of the two halves of the C IV line, as well as observations in the Si IV resonance line 1402.77 A and the O IV intersystem line 1401.16 A, also reveal velocity oscillations at similar frequencies but only over sunspots.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 253
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  • 43
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    The vertical filamentary structures of quiescent prominences (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The thin vertical filaments making up the quiescent prominence plasma, as revealed by fine spatial resolution H-alpha photographs, are characterized by a magnetostatic theory in which a horizontal row of long vertical filaments whose weights are supported by bowed magnetic field lines is described by a class of exact equilibrium solutions. The Kippenhahn-Schlueter (1957) solution for a long sheet without filamentary structures is a member of this class of solutions. In illustrating the role of the magnetic field in supporting and thermally shielding the filament plasma, it is found that the filament can have a sharp transition perpendicular to the local field, while the transition in the direction of the local field is diffuse. A consequence of the filamentary structure is that its support by the Lorentz force requires the electric current to have a component along the magnetic field.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 75; Jan. 198
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  • 44
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    Microstructure and property characterization of sintered Si3N4, SiC, and SiAlON (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Commercially-produced, pressureless sintered Si3N4, SiC, and SiAlON were characterized with respect to density, phases present, bend strength, and oxidation resistance. The room-temperature bend strengths of sintered Si3N4, SiC, and SiAlON are comparable. However, the room-temperature strengths are much lower (approximately 40 to 50%) than the room-temperature strength of hot-pressed Si3N4 (NC-132). The strength loss in Si3N4 and SiAlON materials at high temperature was attributed to a viscous grain-boundary phase, retained during cooling from the sintering temperature. The oxidation resistance of sintered alpha-SiC was the best of any materials tested.
    Keywords: NONMETALLIC MATERIALS
    Type: American Ceramic Society; vol. 65
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  • 45
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    A new brominated polymeric additive for flame retardant glass-filled polybutylene terephthalate (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Attention is called to the undesirable effects (poor ultraviolet light stability and blooming) sometimes introduced by brominated flame retarders. A brominated polymeric additive (BPA) with little or none of these undesirable side effects is compared with decabromobiphenyl oxide (DBBPO). The additive bears the product name F-2300. It is found to be more easily dispersed than DBBPO. The F-2300 is as effective as the DBBPO in the oxygen index test. The improved efficiency of the F-2300 may be explained by its better dispersion in polybutylene terephthalate (PBT). Glass-filled PBT containing F-2300 is found to be more resistant to UV degradation than DBBPO-containing formulas. Formulations with F-2300 therefore have a longer useful outdoor life. F-2300 is a diglycidyl-type polymer containing 50 percent aromatically bound bromine. Its melting point is 112 C, and it is stable up to 372 C. It is pointed out that since its melts at a relatively low temperature, it can be introduced into the formulation as a large agglomerate and still be dispersed evenly throughout the polymer.
    Keywords: NONMETALLIC MATERIALS
    Type: Journal of Fire Retardant Chemistry; 9; Aug. 198
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  • 46
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    XPS, AES and friction studies of single-crystal silicon carbide (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The surface chemistry and friction behavior of a single crystal silicon carbide surface parallel to the 0001 plane in sliding contact with iron at various temperatures to 1500 C in a vacuum of 3 x 10 nPa are investigated using X-ray photoelectron and Auger electron spectroscopy. Results show that graphite and carbide-type carbon are seen primarily on the silicon carbide surface in addition to silicon at temperatures to 800 C by both types of spectroscopy. The coefficients of friction for iron sliding against a silicon carbide surface parallel to the 0001 plane surface are found to be high at temperatures up to 800 C, with the silicon and carbide-type carbon at maximum intensity in the X-ray photoelectron spectroscopy at 800 C. The concentration of the graphite increases rapidly on the surface as the temperature is increased above 800 C, while the concentrations of the carbide-type carbon and silicon decrease rapidly and this presence of graphite is accompanied by a significant decrease in friction. Preheating the surfaces to 1500 C also gives dramatically lower coefficients of friction when reheating in the sliding temperature range of from room temperature to 1200 C, with this reduction in friction due to the graphite layer on the silicon carbide surface.
    Keywords: NONMETALLIC MATERIALS
    Type: Applications of Surface Science (ISSN 0378-5963); 10; 1982
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  • 47
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    A surge observed in H alpha and C IV (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Results are presented of simultaneous measurements of H-alpha (MSDP at Meudon) and C IV (UVSP onboard SMM) of Active Region 2701 made on October 2, 1980. Isodensity and velocity maps were obtained for both lines and these maps were superimposed. Results show a good correlation between the H-alpha and C IV velocities with a surge being observed for 10 minutes. The base of the surge was determined to be located in a bright point in C IV and H-alpha, while the escaping matter followed the same channel ('absorbing' in H-alpha, 'emitting' in C IV). It was found that the velocity along the surge was about 80 km/s in H-alpha and 100 km/s in C IV. In addition, a loop appeared in C IV during the surge. It is concluded that the vertical pressure gradient was capable of driving the surge.
    Keywords: SOLAR PHYSICS
    Type: (ISSN 0273-1177)
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  • 48
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    About the onsets of closely-consecutive homologous flares (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The onsets of closely consecutive homologous flares (CCHF), which are separated by less than 6 hours and most often by about 1 hour, are compared with that of isolated flares (no flare in the region half a day before). Isolated flares appear to be formed of two components, a surging arch and a flaring arch, while a set of CCHF may be composed of consecutive elementary flares or of a series of complex ones. It is shown that the onset of eruptive flare phenomena is not the same for an isolated event and for a member of CCHF (excluding the first) as found in H-alpha and EUV observations, and probably in X-ray observations also. It is suggested that a CCHF set would become a single flare with episodic enhancement of brightness by taking account of the common H-alpha behavior of surging and flaring arches as well as the EUV emission.
    Keywords: SOLAR PHYSICS
    Type: (ISSN 0273-1177)
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  • 49
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    Observations of the longitudinal magnetic field in the transition region and photosphere of a sunspot (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The Ultraviolet Spectrometer and Polarimeter on the Solar Maximum Mission spacraft has observed for the first time the longitudinal component of the magnetic field by means of the Zeeman effect in the transition region above a sunspot. The data presented here were obtained on three days in one sunspot, have spatial resolutions of 10 arcsec and 3 arcsec, and yield maximum field strengths greater than 1000 G above the umbrae in the spot. The method of analysis, including a line-width calibration feature used during some of the observations, is described in some detail in an appendix; the line width is required for the determination of the longitudinal magnetic field from the observed circular polarization. The transition region data for one day are compared with photospheric magnetograms from the Marshall Space Flight Center. Vertical gradients of the magnetic field are compared from the two sets of data; the maximum gradients of 0.41 to 0.62 G/km occur above the umbra and agree with or are smaller than values observed previously in the photosphere and low chromosphere.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 81; Dec. 198
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  • 50
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    Stationarity of magnetohydrodynamic fluctuations in the solar wind (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N83-11007)
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 87; Dec. 1
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  • 51
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    A three-component model of the variability of the solar ultraviolet flux 145-200 nM (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The variability of the ultraviolet flux between 145 and 200 nm over both the eleven-year cycle and the 27-day solar rotation period is examined in terms of chromospheric activity, as determined from ground-based observations of the CaII K chromosphere. A three-component model of the solar UV flux is developed which includes the contributions to the full disk flux from both plage and active network emission. Solar cycle and solar rotation variations derived from the model are compared with the results of satellite and rocket experiments and with the two-component model of Cook et al (1980). Finally, possible ways of improving the model are discussed.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 87; Dec. 1
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  • 52
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    Active-region evolution and solar rotation variations in solar UV irradiance, total solar irradiance, and soft X rays (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Variations in the total solar irradiance, solar UV spectral irradiance, and solar soft X-ray emission caused by active region evolution and solar rotation are analyzed by using concurrent measurements from the NIMBUS 7 and GOES satellites. The observations are interpreted by using simple empirical models that relate ground-based observations of the size and location of sunspots and plages to the full-disk temporal variations. It is found that the major dips in the photospheric total solar irradiance S, which are evident in both satellite measurements and model predictions, are usually not accompanied by outstanding enhancements in the chromospheric and upper photospheric UV spectral irradiance or coronal X rays. The main cause of this difference between the variability of S and of the UV flux is that the total chromospheric plage enhancements are not outstanding at those times when the total sunspot are outstanding. X rays are even more variable because of a much wider CMD sensitivity.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 87; Dec. 1
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  • 53
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    Charging and discharging characteristics of dielectric materials exposed to low- and mid-energy electrons (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Charging and discharging characteristics of dielectric samples exposed to 1-25 keV and 25-100 keV electrons in a laboratory environment are reported. The materials examined comprised OSR, Mylar, Kapton, perforated Kapton, and Alphaquartz, serving as models for materials employed on spacecraft in geosynchronous orbit. The tests were performed in a vacuum chamber with electron guns whose beams were rastered over the entire surface of the planar samples. The specimens were examined in low-impedance-grounded, high-impedance-grounded, and isolated configurations. The worst-case and average peak discharge currents were observed to be independent of the incident electron energy, the time-dependent changes in the worst case discharge peak current were independent of the energy, and predischarge surface potentials are negligibly dependent on incident monoenergetic electrons.
    Keywords: NONMETALLIC MATERIALS
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  • 54
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    Magnetic clouds - Voyager observations between 2 and 4 AU (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-13593)
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 81; Nov. 198
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  • 55
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    Proposed Mg V, Fe XIV and forbidden Fe XVII line identifications in the EUV solar spectrum (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 81; Nov. 198
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  • 56
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    Dynamics of the eruptive prominence of 6 May 1980 and its relationship to the coronal transient (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The active prominence of the 6 May 1980 has been observed between 5.23 and 10.22 UT with the Ultraviolet Spectrometer and Polarimeter (UVSP) on board the Solar Maximum Mission (SMM) satellite. Intensities of 1548 A line of CIV and dopplershifts have been derived. A motion of the magnetic tube maintaining the prominence material is noted. This motion is followed by a coronal transient observed with the Coronagraph and Polarimeter (C/P) between 11 and 13 UT. It is suggested that the event is related to a MHD wave induced by a flare occurring behind the solar disk, and a MHD modeling of the perturbation is proposed.
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics; 114; 1, Oc; Oct. 198
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  • 57
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    Laser processing (1982)
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    Publication Date: 2011-08-18
    Description: Progress in the Progress ceramic materials is reported. Experiments and models for sintering and microstructure evolution are described. Models and data for understanding the kinetics of grain boundary motion and of pore coarsening and new materials for fuel cells and batteries; are developed. New experimental techniques using lasers for forming fine, monosized powders and for forming stable and metastable structures from liquids, and solar materials research are also developed. Colloidal science and ceramics processing are explored; and research programs on the presintering science necessary for controlled green microstructures are outlined.
    Keywords: NONMETALLIC MATERIALS
    Type: The Mater. Process. Res. Base of the Mater. Process. Center; p 198-209
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  • 58
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    Evaluation of waveguide coating materials (1982)
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    Publication Date: 2011-08-18
    Description: Waveguide coating materials were tested at 8470 MHz for insertion loss. Samples of these coatings on waveguide pieces without flanges were tested in an environmental chamber to simulate the effects of high power microwave heating. Test results indicated that three types of coating materials are acceptable with regard to insertion loss. However, simulated microwave heating caused debonding of Metcot 7 and BD-991 coatings, resulting in peelings in the waveguide. The higher cost Chemglaze R104 does not exhibit this problem.
    Keywords: NONMETALLIC MATERIALS
    Type: The Telecommun. and Data Acquisition Rept.; p 68-71
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  • 59
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    Numerical modeling and optimization of polymer melt processing operations (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The application of finite element computer analyses to polymer flows of the type encountered in melt processing operations is described. A code capable of predicting values of fluid veleocity, pressure, shear stress, and temperature at any point within the flow field was developed. As such, is is of value in diagnosing such processing problems as regions of fluid stagnation at which thermal degradation may occur, or regions of excessive shear deformation which lead to thermomechanical damage. It is further able to generate predictions of the forces which must be applied to the melt to achieve the desired flow, and this information is of value in designing processing equipment of optimal efficiency and minimum energy consumption.
    Keywords: NONMETALLIC MATERIALS
    Type: The Mater. Process. Res. Base of the Mater. Process. Center; p 117-119
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  • 60
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    Rapid quenching effects in glassy polymers (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Using a specially constructed microbalance for hydrostatic weighing, density changes in PVC thin film due to rapid quenching through the glass transition temperature were observed. The more severe the quench, the greater the free volume content. Isobaric volume recovery of PVC was also studied by volume dilatometry. Both show aging of relaxing molecular rearrangements taking place as a linear function of logarithmic aging time at room temperature. Distribution of retardation times and Primak's distributed activation energy spectra were applied to the volume recovery data. The concomitant changes in mechanical properties of PVC after quenching were monitored by tensile creep stress-stran to failure rates. All reflect the presence of excess free volume content due to rapid quenching.
    Keywords: NONMETALLIC MATERIALS
    Type: The Mater. Process. Res. Base of the Mater. Process. Center; p 79-89
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  • 61
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    The structure, stability and flaring of solar coronal loops (1982)
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    Publication Date: 2011-08-18
    Description: A review is given of recent progress in the theory of the magnetohydrodynamic behavior of coronal loops, beginning with a brief characterization of thy observations. The equilibrium magnetic field is described, along with the consequences of the empirical requirement for short-term, or infinite-conductivity, stability which is shown to be dominated by the end-effect influence of thy quasi-rigid photosphere. A new loop-flare model is then developed, which takes account of the finite loop length. The primary resistive-sausage-mode instability exhibits the necessary threshold behavior, and produces a number of spatially and energetically distinct flare-release manifestations.
    Keywords: SOLAR PHYSICS
    Type: Societa Astronomica Italiana; vol. 53
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  • 62
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    Quadrupole distortions of the heliospheric current sheet in 1976 and 1977 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Latitudinal variations in the position of the heliospheric current sheet were investigated using interplanetary measurements from Helios A, Helios B, IMP 8, and white light corona measurements in the period May 1976 to May 1977. The latitude of the heliospheric current sheet between 0.3 AU and I AU is consistent with that of the maximum brightness curve of white light polarization brightness at 1.75 solar radii within approximately + or - 7 deg. The combined data sets show that the four-sector magnetic sector pattern observed in the ecliptic plane for most of this epoch could be attributed to a warped current sheet whose shape near the sun resembles a saddle surface that is nearly symmetrical about the equatorial plane. The latitudinal extent of the current sheet is on the average 8 deg and the maximum extent is 15 deg (except on one rotation, when it is 20 deg). These results can be interpreted as a consequence of the solar magnetic field, the dominant components of the field being due to a dipole nearly aligned with the sun's spin axis and a quadrupole component whose strength is about 17 percent of the dipole.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 87; Dec. 1
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  • 63
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    Measurements of solar transition zone velocities and line broadening using the ultraviolet spectrometer and polarimeter on the Solar Maximum Mission (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The UVSP instrument on SMM is able to observe solar regions at two wavelengths in the same line with a band-pass of 0.3 A. Intensity and Doppler velocity maps are derived. It is shown that the numerical values are sensitive to the adopted Doppler width and the range of velocities is limited to within 30 km/sec. A method called Double Dopplergram Determination (DDD) is described for deriving both the Doppler width and the velocity (up to 80 km/sec), and the main sources of uncertainties are discussed. To illustrate the method, a set of C IV 1548 A observations is analyzed according to this procedure. The mean C IV Doppler width measured (0.15 A) is comparable to previous determinations. A relation is found between bright regions and down-flows. Large Doppler widths correspond to strong velocity gradients.
    Keywords: SOLAR PHYSICS
    Type: Astronomy and Astrophysics; 115; 2, No; Nov. 198
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  • 64
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    A dispersion law for solar oscillations (1982)
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    Publication Date: 2011-08-18
    Description: The simple model of p-mode solar oscillations of Liebacher and Stein (1981), in which the acoustic vibrations are trapped in a resonant cavity taking the form of a spherical shell below the solar surface, is compared with Doppler shift observations of vertical velocities. The model is shown to predict a modified dispersion law in which the sound travel time across the cavity is a function of the ratio of the temporal frequency to the horizontal wavenumber, resulting in a single curve when the temporal frequency is plotted against the wavenumber. Frequencies derived from a two-dimensional power spectrum of velocity observations are found to conform to a modified version of the dispersion relation, and that only when the fundamental mode is excluded. Results thus suggest that all modes with the same frequency/wavenumber ratio are trapped in an identical cavity, or, more plausibly, that the difference in upper boundary conditions for different modes has minimal effect on the resulting frequencies.
    Keywords: SOLAR PHYSICS
    Type: Nature; 300; Nov. 18
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  • 65
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    Flare buildup in X-rays, UV, microwaves and white light (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Coordinated observations using space and ground-based instruments were made of active region complex numbers 2522/2530, 24-30 June, 1980. The 10 largest flares from these regions were of importance M1-M6 in X-rays, and all were observed from satellites, except for one observed from a balloon. Several kinds of buildup signature have been found in the tens of minutes before these flares. Among these signatures are the following: (1) relative faintness in X-ray lines of the pre-flare pixels, (2) X-ray (5-15 keV) 'flashes' at points displaced by 1-2 arcmin from the flare site, (3) rising filaments seen in H-alpha and ultraviolet, (4) microwave intensification, polarization increase, and polarization flip, and (5) coronal disturbances above limb flares at or before the impulsive phase.
    Keywords: SOLAR PHYSICS
    Type: (ISSN 0273-1177)
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  • 66
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    Flare build-up study: Homologous flares group - Interim report (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: When homologous flares are broadly defined as having footpoint structures in common, it is found that a majority of flares fall into homologous sets. Filament eruptions and mass ejection in members of an homologous flare set show that maintainance of the magnetic structure is not a necessary condition for homology.
    Keywords: SOLAR PHYSICS
    Type: (ISSN 0273-1177)
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  • 67
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    Particle acceleration by coronal and interplanetary shock waves (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Utilizing many years of observation from deep space and near-earth spacecraft a theoretical understanding has evolved on how ions and electrons are accelerated in interplanetary shock waves. This understanding is now being applied to solar flare-induced shock waves propagating through the solar atmosphere. Such solar flare phenomena as gamma-ray line and neutron emissions, interplanetary energetic electron and ion events, and Type II and moving Type IV radio bursts appear understandable in terms of particle acceleration in shock waves.
    Keywords: SOLAR PHYSICS
    Type: (ISSN 0273-1177)
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  • 68
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    A magnetic cloud and a coronal mass ejection (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An interplanetary magnetic cloud observed by the Helios 1 spacecraft was found to be associated with a coronal mass ejection observed by the NRL Solwind coronagraph on the spacecraft P78-1. The magnetic cloud was observed on June 20, 1980, when Helios 1 was at 0.54 AU and nearly 90 deg west of the earth-sun line. This was associated with a large loop-like coronal mass ejection observed over the west limb on June 18, 1980, moving toward Helios 1. The speed of the front of the event at Helios 1 was (470 + or - 10) km/s, which is close to the mean transit speed (approximately 500 km/s). The magnetic cloud was similar to others described in the literature: The magnetic field strength was higher than average; the density was relatively low; the magnetic pressure greatly exceeded the ion thermal pressure; and the magnetic field direction changed through the cloud by rotating parallel to a plane which was highly inclined with respect to the ecliptic.
    Keywords: SOLAR PHYSICS
    Type: Geophysical Research Letters; 9; Dec. 198
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  • 69
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    Scaling-law equilibria for calcium in canopy-type models of the solar chromosphere (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Scaling laws for resonance line formation are used to obtain approximate excitation and ionization equilibria for a three-level model of singly ionized calcium. The method has been developed for and is applied to the study of magnetograph response in the 8542 A infrared triplet line to magnetostatic canopies which schematically model diffuse, nearly horizontal fields in the low solar chromosphere. For this application, the method is shown to be efficient and semi-quantitative, and the results indicate the type and range of effects on calcium-line radiation which result from reduced gas pressure inside the magnetic regions.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 79; Aug. 198
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  • 70
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    Hydromagnetic stability of coronal arcade structures The effects of photospheric line tying (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A model is given of the magnetic-field equilibrium and possible dynamic excitations of a solar coronal arcade. Such structures are well observed in the spectral range from H-alpha to X-rays and often give rise to two-ribbon flares. However, the preflare state must be stable to ideal magnetohydrodynamic disturbances, and this problem is treated with particular attention to the necessary foot-point boundary conditions. With reasonably general perturbation set, an energy-principle analysis is used to show the strong stabilizing influence of inertial field-line tying at the photosphere.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 79; Aug. 198
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  • 71
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    The three-dimensional structure of atmospheric magnetic fields in two active regions (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The magnetic field above two unrelated active regions on September 11-12, 1974 has been studied by means of magnetograms obtained in C I 9111, Fe I 8688, Ca II 8542, and H-alpha. In C I, originating low in the photosphere, the fields are strong and sharply defined, by contrast with Ca II and H-alpha, where they are very diffuse. The similar diffuseness of Fe I is due to the spreading of the field with height to form nearly horizontal magnetic canopies over regions free of field at lower levels. Within a region between two small sunspots some 140 Mm apart, the canopy height is typically 300-400 km, and it is about 150-250 km within a small superpenumbra. It is hypothesized that the chromospheric fibrils taken to delineate the field configuration are not due primarily to lateral variations in field, but rather to differences in density or excitation of gas across the lines of force.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 79; Aug. 198
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  • 72
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    Magnetograph response to canopy-type fields (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The response of longitudinal-field magnetographs to magnetic fields which are semi-infinite or confined to a horizontal layer is discussed with respect to the interpretation of solar diffuse fields, observed towards the limb, in terms of magnetic canopy models. Numerical results are presented for several reference solar models and typical 'calibration' curves are shown for the CI 9111 A, Fe I 8688 A, and Ca II 8542 A lines in magnetostatic atmospheres derived from a mean model. A procedure is developed for determining the base heights of magnetic canopies from observations with an uncertainty not exceeding the order of a pressure scale height. Until definitive information regarding atmospheric structure inside flux tubes can be developed from theory or observation, reliable field strengths cannot be derived from the data.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 79; Aug. 198
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  • 73
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    Evidence for a poleward meridional flow on the sun (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Two subsets of all polar zone filaments, designated polemost filament and polar filament bands, are defined for observational study of their behavior, which is compared with the evolution of the polar magnetic field over Howard and LaBonte's (1981) activity cycle. The magnetic data show that the polar magnetic fields are built up and maintained by the episodic arrival of discrete f-polarity regions originating in active region latitudes and subsequently drifting to the poles. F-polarity regions are carried poleward by a meridional flow, rather than by diffusion. It is noted that the mean latitude of the polemost filaments tracks the boundary of the polar field cap, and undergoes an equatorward dip during each arrival of additional polar field, and that the polar filament bands track the boundary latitudes of the unipolar regions, drifting poleward with the regions at about 10 m/sec.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 79; Aug. 198
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  • 74
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    Unusual coronal activity following the flare of 6 November 1980 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The major two-ribbon flare that occurred on November 6, 1980 is discussed, using data from the hard X-ray imaging spectrometer aboard the SMM satellite. The post-flare X-ray arch and loops are analyzed, showing the flare characteristics, the coronal arch, the time variations of X-rays after the flare, and the time variation of the maximum intensity at the top of the coronal arch in the 3.5-5.5 keV range. A comparison is made with an earlier arch. The post-flare conronal brightness variations are discussed, including a correlation with a 169 MHz noise stomr, the absence of chromospheric excitation, the brightness and temperature of the X-ray arch, the locations of the brightenings, and the details of the first and fifth brightenings. Problems posed by the observations are discussed.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 80; Sept
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  • 75
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    Solar irradiance modulation by active regions during 1980 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The solar irradiance modulation due to active regions during 1980 has been investigated in detail. Specifically, the uncertainties caused by ground-based data used as input in the modeling effort, and by currently incomplete knowledge of the proper parameters that describe the angular variation of sunspot and facular contrasts are estimated. It is concluded that the most significant uncertainties are due to errors in area measurements and, possibly, varying spot and facular brightness. A 'standard model' for later use is derived to a best-fit technique of the currently available ACRIM irradiance data and the predictions of models with appropriately varied parameters. Finally, the expected irradiance for the entire year of 1980 is computed.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 80; Sept
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  • 76
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    The dynamics of accelerating coronal bullets (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Results are presented of computer simulations of the jets that accelerate through the corona at velocities of 50 to 400 km/s. Particular emphasis is placed on the sensitivity of the induced acceleration to the form in which energy is put into the system. A comparison is made between the observed and predicted physical characteristics of the high-velocity bullets; the potential contribution of the bullets to the mass and energy balance of the solar corona is considered. It is found that the velocity and temperature evolution of the bullets can be modeled successfully by assuming energy input in the form of an external force, pushing continuously on the ejected material. From the physical characteristics of the model bullets and the energy input required to reproduce the observations, it is concluded that the bullets may constitute a significant fraction of the coronal mass flux but only a negligible component of the coronal energy budget.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 261
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  • 77
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    Development of low-thermal expansion mullite bodies (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A series of ceramic compositions based on variations in the crystal-glass ratio of a mullite body were developed. The thermal expansion of these compositions varies from 3.7 to 5.0 x 10 to the -6th/deg C to 800 C. The materials are particularly useful for applications involving silicon, in that an identical thermal expansion is available. The high-temperature creep data for the lower-expansion compositions are inferior as a result of their higher glass contents. Raw material sources and fabrication procedures for specific compositions are given.
    Keywords: NONMETALLIC MATERIALS
    Type: American Ceramic Society; vol. 65
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  • 78
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    High-resolution X-ray spectra of solar flares. VI - Impulsive soft X-ray flares (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Doschek et al. (1980) and Feldman et al. (1980) have discussed high-resolution soft X-ray spectra of solar flares. The present investigation is concerned with the characteristics of the impulsive events as observed in soft X rays and the cooling of the flare plasma in terms of energy loss processes. A class of intense, short-lived solar flares which appear to be characterized by very high densities at high temperatures is found. For the 1979 November 6 event, the cooling time is so rapid that the density obtained may be a lower limit. The main cooling mechanism for the flares is found to be radiative. Two of the events are associated with strong gamma-ray emission and both of these events are very unusual in their soft X-ray emission. The 1979 November 9 flare shows extremely broad X-ray emission lines during the rise phase, indicative of nonthermal velocities of the order of 300 km/s.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 260
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  • 79
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    Quantitative tests of a steady state theory of solar wind electrons (1982)
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    Publication Date: 2011-08-18
    Description: A comparison is made of IMP 6, 7 and 8 electron data with the predictions of a solar wind electron steady state theory in which the control of transport by the macroscopic interplanetary electric and magnetic fields, as well as elastic Coulomb collisions with solar wind protons and thermal electrons, is assumed. While a ratio of forward to backward phase density for field-aligned extrathermal electrons of 6:1 is predicted, electron distribution measurements within the high speed solar wind show this ratio to be typically about an order of magnitude larger. A set of solar wind bulk speed anticorrelations predicted by the theory on the basis of a larger set of assumptions cannot be found in the IMP electron data set, so that improved agreement may require such modifications of the theory's assumptions as the inclusion of inelastic Coulomb and/or wave electron collisions.
    Keywords: SOLAR PHYSICS
    Type: Journal of Geophysical Research; 87; Sept. 1
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  • 80
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    Magnetic energy storage and conversion in the solar atmosphere (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N81-33114)
    Keywords: SOLAR PHYSICS
    Type: Space Science Reviews; 31; 4, 19; 1982
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  • 81
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    Observational constraints for a theoretical model describing the soft X-ray flare (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: High-resolution solar flare X-ray spectra have recently been obtained from X-ray spectrometer experiments flown on an Air Force spacecraft (P78-1) launched on 1979 February 24. Interpretation of the spectra has produced new results concerning the physical conditions and time behavior of the thermal soft X-ray emitting plasma at temperatures near 20,000,000 K. It is argued that soft and hard X-ray events are not causally related to each other, but are simply two different manifestations of flare energy release. They probably occur in different plasma volumes. The source of the preflare plasma appears to be in the cooler parts of the solar atmosphere, perhaps transition region loops with initial temperatures of 100,000 K and densities of 10 to the 11th per cu cm. Continuous energy input, rather than sequential activation of loops, is required to explain the observations. Compression coupled with chromospheric ablation may produce the high densities in coronal flare loops.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 255
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  • 82
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    Addition polyimide adhesives containing various end groups (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Addition polyimode oligomers have been synthesized from 3,3 prime, 4,4 prime-benzophenone tetracarboxylic acid dianhydride and 3,3 prime-methylenedianiline using a variety of latent crosslinking groups as end-caps. The nominal 1300 molecular weight imide prepolymers were isolated and characterized for solubility in amide, chlorinated and ether solvents, melt-flow and cure properties, glass transition temperature, and thermal stability on heating in an air atmosphere. Adhesive strengths of the polyimides were obtained both at ambient and elevated temperatures before and after aging at 232 C. Properties of the novel addition polyimides were compared to a known nadic end-capped adhesive, LARC-13.
    Keywords: NONMETALLIC MATERIALS
    Type: Polymer Engineering and Science; 22; 1, Ja; Jan. 198
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  • 83
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    Observations of solar flare transition zone plasmas from the Solar Maximum Mission (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The spatial and temporal evolution of the Si IV and O IV intensity, density and mass motions in preflare and flare transition zone plasmas are studied for the case of the April 8, 1980 flare. It is found that: (1) the UV flare observed in the Si IV and O IV lines is unambiguously identified as occurring in a low-lying, preexisting transition zone loop which spanned the magnetic neutral line separating a larger leader spot and a newly emerged, isolated spot of opposite polarity; (2) at the onset of the flare, the easternmost footpoint, which was anchored in an isolated spot region of high longitudinal magnetic field gradient, showed sudden, impulsive brightening with large intensity increases; and (3) the release flare energy was transported by way of large-scale connecting field lines to other parts of the active region, producing the hot plasma and H-alpha kernels observed near the trailing spot.
    Keywords: SOLAR PHYSICS
    Type: Astrophysical Journal; vol. 253
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  • 84
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    Recurrence of solar activity - Evidence for active longitudes (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: It is pointed out that the autocorrelation coefficients of the daily Wolf sunspot numbers over a period of 128 years reveal a number of interesting features of the variability of solar activity. Besides establishing periodicities for the solar rotation, solar activity cycle, and, perhaps, the 'Gleissberg Cycle', they suggest that active longitudes do exist, but with much greater strength and persistence in some solar cycles than in others. Evidence is adduced for a variation in the solar rotation period, as measured by sunspot number, of as much as two days between different solar cycles.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 76; Feb. 198
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  • 85
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    The equatorial photospheric rotation rate (1982)
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    Publication Date: 2011-08-18
    Description: The equatorial photospheric rotation rate was observed on 14 days in 1978-1980. The resulting rate, 14.14 + or - 0.04 deg/day, is found to be 2% slower than the rate observed for long-lived sunspots. Tables giving sidereal equatorial rotation rates measured with the line 10905 A Cr I and 6315 A Ni I are included.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 76; Feb. 198
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  • 86
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    Quick matching technique to study the relationship between solar radius and luminosity variations (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: A simple matching technique is developed which makes it possible to compute the response of the solar envelope to perturbations which occur within the solar convective region in timescales of importance to climate. The technique is applied to perturbation of the convective efficiency (alpha-mechanism) and of the nongas component of the pressure in different regions of the convection zone (beta-mechanism). The results indicate that whereas either perturbation affects the solar luminosity, the alpha-mechanism has almost no effect on the solar outer radius, regardless of the affected region. The beta-mechanism, however, produces radius changes which may be large if the location of perturbation is deep enough.
    Keywords: SOLAR PHYSICS
    Type: Solar Physics; 76; Feb. 198
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  • 87
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    Effect of X-ray flux on polytetrafluoroethylene in X-ray photoelectron spectroscopy (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The effect of the X-ray flux in X-ray photoelectron spectroscopy (STAT) on the constitution of the polytetrafluoroethylene (PTFE) surface has been examined. The radiation dose rate for our specimen was about 10 to the 7th rad/s. The structure, magnitude and binding energy of the C(1s) and F(1s) features of the XPS spectrum and the mass spectrum of gaseous species evolved during irradiation are observed. The strong time dependence of these signals over a period of several hours indicated that the surface constitution of PTFE is greatly affected by this level of radiation dose. The results are consistent with the development of a heavily cross-linked or branched structure in the PTFE surface region and the evolution of short chain fragments into the gas phase.
    Keywords: NONMETALLIC MATERIALS
    Type: Journal of Vacuum Science and Technology; 20; Feb. 198
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  • 88
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    Solar irradiance modulation by active regions from 1969 through 1980 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: The solar irradiance variations resulting from sunspot deficits and facular excesses in emission have been calculated from 1969 through 1980. Agreement appears to exist between the calculations and the major features seen with the Nimbus 7 cavity pyrheliometer and with both the major and minor features detected by the Solar Maximum Mission ACRIM experiment. The 12-year irradiance variations calculated suggest a larger variance with increased solar activity, and little change in the average irradiance with solar activity. The largest excursions over these 12 years show a 0.4% variation. Removal of the activity influences upon solar irradiance during the numerous rocket experiments observing the solar constant may allow a better value for this quantity to be determined.
    Keywords: SOLAR PHYSICS
    Type: Geophysical Research Letters; 9; Jan. 198
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  • 89
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    Creep of plasma-sprayed-ZrO2 thermal-barrier coatings (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Specimens of plasma-sprayed-zirconia thermal-barrier coatings with three different porosities and different initial particle sizes were deformed in compression at initial loads of 6900, 13,800, and 24,100 kPa (1000, 2000, and 3500 psi) and temperatures of 1100, 1250, and 1400 C. The coatings were stabilized with lime, MgO, and two different concentrations of Y2O3. Creep began as soon as the load was applied and continued at a constantly decreasing rate until the load was removed. Temperature and stabilization had a pronounced effect on creep rate while the stress, particle size, and porosity had a lesser effect. Creep deformation was due to cracking and particle sliding.
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  • 90
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    Some inelastic effects of thermal cycling on ZrO2-Y2O3 materials (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: An analysis has been developed which relates the effects of inelastic behavior of Y2O3 stabilized ZrO2 (YSZ) materials. The results show these materials to be sensitive to small changes in temperature and are supported by measurements of inelastic behavior in disk and bar specimens at temperatures as low as 1010 C (1850 F). At higher thermomechanical loads, the test specimens can deform to strains greater than 1 percent and for bar specimens, with sufficient strength, to remain bonded to the metallic substrate.
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  • 91
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    Use of fiber-like materials to augment cycle life of thick, thermoprotective-seal coatings (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-32633)
    Keywords: NONMETALLIC MATERIALS
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  • 92
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    Effects of arc current on the life in burner-rig thermal cycling of plasma-sprayed ZrO2-O3 (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: (Previously announced in STAR as N82-17453)
    Keywords: NONMETALLIC MATERIALS
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  • 93
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    A ceramic nozzle for the NASA-Langley 2.4-m /8.0-ft/ high temperature structures tunnel (1982)
    In:  Other Sources
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    Publication Date: 2011-08-18
    Description: Two materials, a refractory castable ceramic and a SiO2-SiO2 composite, were fabricated as nozzle inserts for the Langley Research Center's 2.4-m (8.0-ft) high temperature structures tunnel. The high pressure and intense heat of the CH4-air products of the combustion-gas stream limits the materials that can be used in this tunnel. The castable-ceramic material showed good resistance to erosion and the thermal loads imposed on it by the gas stream but failed in tension when subjected to high hoop stresses. The SiO2-SiO2-composite nozzle insert withstood the thermomechanical loads but eroded unacceptably with increasing test temperature and pressure.
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  • 94
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    Some characteristics of polymers in composite materials and as electrical conductors (1982)
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    Publication Date: 2011-08-18
    Description: The characteristics of carbon fibers (CF) made from polyacrylonitrile (PAN) materials are discussed, together with research on conducting polymers. CF materials have better mechanical properties, chemical inertness, and higher stiffness than metallic materials but are subject to environmental instability, flammability, and delamination fatigue. Polymerization procedures for the monopolymer PAN are described, noting the use of SEM and X-ray diffraction techniques for studying the fiber structure. High modulus and strength of CF are caused by covalent sp(2) bonds in hexagonal carbon rings, which are stronger than the same links in diamonds. Details of the molecular chain structures and macroformations, stress-strain as a function of temperature, and thermosetting and glass transition temperatures of polymers are provided. Computational quantum chemistry techniques are being applied to studying electrical conductance in polymers, mainly to discover ways to stabilize the materials. Doped CH(x) has exhibited photovoltaic properties and other polymers have become superconductors at cryogenic temperatures.
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  • 95
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    Ultrahigh molecular weight aromatic siloxane polymers (1982)
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    Publication Date: 2016-06-07
    Description: The condensation of a diol with a silane in toluene yields a silphenylene-siloxane polymer. The reaction of stiochiometric amounts of the diol and silane produced products with molecular weights in the range 2.0 - 6.0 x 10 to the 5th power. The molecular weight of the product was greatly increased by a multistep technique. The methodology for synthesis of high molecular weight polymers using a two step procedure was refined. Polymers with weight average molecular weights in excess of 1.0 x 10 to the 6th power produced by this method. Two more reactive silanes, bis(pyrrolidinyl)dimethylsilane and bis(gamma butyrolactam)dimethylsilane, are compared with the dimethyleminodimethylsilane in ability to advance the molecular weight of the prepolymer. The polymers produced are characterized by intrinsic viscosity in tetrahydrofuran. Weight and number average molecular weights and polydispersity are determined by gel permeation chromatography.
    Keywords: NONMETALLIC MATERIALS
    Type: NASA. Marshall Space Flight Center The 1982 NASA(ASEE Summer Fac. Fellowship Program; 13 p
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  • 96
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    Structural application of high strength, high temperature ceramics (1982)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Description: The operation of rocket engine turbine pumps is limited by the temperature restrictions of metallic components used in the systems. Mechanical strength and stability of these metallic components decrease drastically at elevated temperatures. Ceramic materials that retain high strength at high temperatures appear to be a feasible alternate material for use in the hot end of the turbopumps. This project identified and defined the processing parameters that affected the properties of Si3N4, one of candidate ceramic materials. Apparatus was assembled and put into operation to hot press Si3N4 powders into bulk material for in house evaluation. A work statement was completed to seek outside contract services to design, manufacture, and evaluate Si3N4 components in the service environments that exists in SSME turbopumps.
    Keywords: NONMETALLIC MATERIALS
    Type: NASA. Marshall Space Flight Center The 1982 NASA(ASEE Summer Fac. Fellowship Program; 11 p
    Format: application/pdf
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  • 97
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    Ion Beam Sputtered Coatings of Bioglass (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The ion beam sputtering technique available at the NASA-Lewis was used to apply coatings of bioglass to ceramic, metallic, and polymeric substrates. Experiments in vivo and in vitro described investigate these coatings. Some degree of substrate masking was obtained in all samples although stability and reactivity equivalent to bulk bioglass was not observed in all coated samples. Some degree of stability was seen in all coated samples that were reacted in vitro. Both metallic and ceramic substrates coated in this manner failed to show significantly improved coatings over those obtained with existing techniques. Implantation of the coated ceramic substrate samples in bone gave no definite bonding as seen with bulk glass; however, partial and patchy bonding was seen. Polymeric substrates in these studies showed promise of success. The coatings applied were sufficient to mask the underlying reactive test surface and tissue adhesion of collagen to bioglass was seen. Hydrophilic, hydrophobic, charged, and uncharged polymeric surfaces were successfully coated.
    Keywords: NONMETALLIC MATERIALS
    Type: NASA-CR-188778 , NAS 1.26:188778
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  • 98
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    Advanced Strain-Isolation-Pad Material with Bonded Fibrous Construction (1982)
    In:  CASI
    Details
    Publication Date: 2019-06-28
    Description: The feasibility of utilizing air lay and liquid lay felt deposition techniques to fabricate strain isolation pad (SIP) materials for the Space Shuttle Orbiter was demonstrated. These materials were developed as candidate replacements for the present needled felt SIP used between the ceramic tiles and the aluminum skin on the undersurface of the Orbiter. The SIP materials that were developed consisted of high temperature aramid fibers deposited by controlled fluid (air or liquid) carriers to form low density unbonded felts. The deposited felts were then bonded at the fiber intersections with a small amount of high temperature polyimide resin. This type of bonded felt construction can potentially eliminate two of the problems associated with the present SIP, viz., transmittal of localized stresses into the tiles and load history dependent mechanical response. However, further work is needed to achieve adequate through thickness tensile strength in the bonded felts.
    Keywords: NONMETALLIC MATERIALS
    Type: NASA-CR-166599 , NAS 1.26:166599
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  • 99
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    Serf studies of mass motions arising in flares (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: It is believed that radio type IVs, co-spatial with dense hot plasmoids, may be the result of a plasma radiation emission mechanism. The injection of mass into the corona was recently observed in chromospheric and coronal lines with magnetic field changes and also at very high speeds into loops. The start time of coronal loop transients, if extrapolated to the chromosphere, in most cases precedes flare H-alpha or X-ray emission. Observational inferences from polarization and other studies are seen as favoring the three-dimensional bubble over the planar loop as a description of coronal mass motions.
    Keywords: SOLAR PHYSICS
    Type: (ISSN 0273-1177)
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  • 100
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    Propagation of energetic particles in the solar wind (1982)
    In:  Other Sources
    Details
    Publication Date: 2019-06-28
    Description: A summary is given of recent results from the direct determination of the charge states of He, C, O, and Fe. These results are used in discussing compositional variations during individual solar particle events. It is shown that ratio changes by a factor of approximately 10 during the onset phase of solar particle events can be explained not only by rigidity-dependent interplanetary propagation but also by rigidity-dependent diffusive propagation in the corona. Increasing experimental evidence is seen that other processes, such as compositional variations at the source and discontinuities of the interplanetary magnetic field separating two different particle populations, may be important. No common explanation is seen for all the variations, and it is concluded that each must be investigated on its own.
    Keywords: SOLAR PHYSICS
    Type: (ISSN 0273-1177)
    Format: text
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