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At least 775 records · Page 43

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NASA NTRS1975

ATS-5 observations of plasma sheet particles before the expansion-phase onset, appendix C.

Behavior of the plasma sheet around its earthward edge during substorms was studied by using high resolution (every 2.6 sec) measurements of proton and electron fluxes by ATS-5. In the injection region near midnight the flux increase at the expansion-phase onset is shown to lag behind the onset of the low-latitude positive bay by several minutes. Depending upon the case, before the above increase (1) the flux stays at a constant level, (2) it gradually increases for some tens of minutes, or (3) it briefly drops to a low level. Difference in the position of the satellite relative to the earthward edge and to the high-latitude boundary of the plasma sheet is suggested as a cause of the above difference in flux variations during the growth phase of substorms. Magnetograms and tables (data) are shown.

Fujii, K.↗

NASA NTRS1975

The current sheet in Jupiter's magnetosphere

A theoretical model is presented for the plasma in the Jovian magnetosphere whose pressure is comparable to the corotational energy density. The model predicts a thin current sheet of 1 Jupiter radius to 2 Jupiter radii half-thickness. The current sheet lies almost precisely in the magnetic equatorial plane and is not appreciably warped as suggested previously.

Goertz, C. K.↗

NASA NTRS1976

A metal sheet stiffened by a partially debonded composite quarter-plate

An isotropic sheet stiffened by means of an orthotropic quarter-plate is considered. The quarter-plate is assumed to be perfectly bonded to the metal sheet everywhere except an area of debonding which may develop due to high stress concentrations. The adhesive which has a small constant thickness is treated as a shear spring. The loads are applied at infinity and supposed to be transmitted through the metal plate. Shear stress distribution between the two plates was obtained from the continuity of displacements along an area where they were bonded to each other.

Arin, K.↗

NASA NTRS1976

The current sheet in Jupiter's magnetosphere

A theoretical model is presented for the plasma in the Jovian magnetosphere whose pressure is comparable to the corotational energy density. The model is consistent with a thin current sheet of half thickness equal to 1 or 2 Jupiter radii. The current sheet lies almost precisely in the magnetic equatorial plane and is not appreciably warped, as has been suggested previously. Warping would occur only if the plasma pressure were much less than the corotational energy density

Goertz, C. K.↗

NASA NTRS1977

Molding cork sheets to complex shapes

Partially cured cork sheet is easily formed to complex shapes and then final-cured. Temperature and pressure levels required for process depend upon resin system used and final density and strength desired. Sheet can be bonded to surface during final cure, or can be first-formed in mold and bonded to surface in separate step.

Sharpe, M. H.↗

NASA NTRS1976

Variations in plasma characteristics near D sheets in the solar wind

A strong interplanetary shock was detected by the Pioneer 8 magnetometer, plasma probe, and wave instrument at 0048 UT, on June 11, 1968. During the rest of this day the interplanetary medium was highly disturbed as seven well-defined current layers or D sheets, as well as a number of other localized interaction regions, swept past the spacecraft. The local plasma characteristics that were best correlated with passage of the D sheets appeared to involve changes in the suprathermal electron population. Changes in the 400-Hz wave levels were also detected near the discontinuities during periods when the local ion plasma frequency was near 400 Hz, but the limited measurement capability of the Pioneer 8 wave instrument does not allow an unambiguous identification of the wave-particle interactions associated with these measurements.

Scarf, F. L.↗

NASA NTRS1977

Observations of energetic electrons /E no less than about 200 keV/ in the earth's magnetotail - Plasma sheet and fireball observations

An earlier paper by the authors (1976) has reported on energetic electron anisotropies observed in conjunction with the acceleration regions identified by Frank et al., (1976). The present paper gives more detailed analyses of observations in the distant plasma sheet, including specific features of intensities, energy spectra, and pitch angle distributions of the very energetic electrons associated with intense plasma particle events, with energies ranging between 50 eV and 45 keV, detected with an electron/isotope spectrometer aboard the earth-orbiting spacecraft Imp 8. Two domains are considered: the plasma sheet and the regions near and within the localized magnetotail acceleration regions known as the fireball regions. The instrumentation used offered a number of observational advantages over many previous studies, including inherently low background, large geometric factors, excellent species identification, good angular distribution measurement capability, and availability of high resolution of differential intensities.

Baker, D. N.↗

NASA NTRS1977

Observations of magnetic merging and the formation of the plasma sheet in the earth's magnetotail

Particle and magnetic field observations of the field line merging process in the earth's magnetotail are presented. By analyzing the lunar shadow pattern of electron fluxes detected by the lunar-orbiting Apollo 16 subsatellite it has been possible to identify the topology and to measure the velocity of the magnetotail field lines. The observations reported here were made as the moon crossed the separatrix between premerging and merged field lines. The measured field line velocities toward the merging region were 30-60 km/s, and the thickness of the separatrix was estimated to be about 2000 km. Most of the magnetic energy released in the merging process appears to go into the energization of particles. The length and the thickness of the merging region are inferred to be of the order of about 10 earth radii and about 4000 km, respectively. The energized particles travel away from the merging region along the separatrix. Those headed earthward may form the plasma sheet by being trapped on closed field lines. The rate of energization and the energy spectrum of those particles are consistent with those required for formation of the plasma sheet.

Lin, R. P.↗

NASA NTRS1979

Controlling the growth of silicon sheets

Automated systems regulates sheet width, thickness, and composition. Deviations from preset brightness levels create error signals that alter gas flow, crystal-pulling speed, and melt temperature to produce uniform single-crystal sheets.

Ciszek, T. F.↗

NASA NTRS1978

Subsonic longitudinal and lateral-directional static aerodynamic characteristics of a general research fighter configuration employing a jet sheet vortex generator

A configuration concept for developing vortex lift, which replaces the physical wing strake with a jet sheet generated fluid strake, was investigated on a general research fighter model. The vertical and horizontal location of the jet sheet with respect to the wing leading edge was studied over a momentum coefficient range from 0 to 0.24 in the Langley 7- by 10-foot high speed tunnel over a Mach number range from 0.3 to 0.8. The angle of attack range studied was from -2 to 30 deg at sideslip angles of 0, -5, and 5 deg. Test data are presented without analysis.

Huffman, J. K.↗

NASA NTRS1978

Aerodynamic characteristics of a jet sheet vortex generator

A configuration concept for augmenting the lift capability of low aspect ratio, thin wings, typically used on fighter aircraft was investigated. The fluid strake concept uses a jet sheet formed by blowing from a series of small orifices located in the side of the fuselage ahead of the wing to generate a stable vortex flow over the wing at high angle of attack. The effect of the location of the fluid strake relative to the wing was investigated for three different designs of the in-line orifices using a half-span model tested in a 7 by 10 foot low speed tunnel. Based on the results of the low speed test, a jet sheet producing module was incorporated into a NASA general research fighter model and tested in the Langley 7 by 10 foot high speed tunnel to determine the effectiveness of the fluid strake as a lift-enhancement device in the high-speed maneuver regime. Tests were conducted over a Mach number range from 0.3 to 0.8, with a jet momentum coefficient range from 0 to 0.24. Significant lift increments resulted at the higher angles of attack and drag polars were improved.

Ziegler, H.↗

NASA NTRS1978

An investigation of the astronomical theory of the ice ages using a simple climate-ice sheet model

The astronomical theory of the Quaternary ice ages is incorporated into a simple climate model for global weather; important features of the model include the albedo feedback, topography and dynamics of the ice sheets. For various parameterizations of the orbital elements, the model yields realistic assessments of the northern ice sheet. Lack of a land-sea heat capacity contrast represents one of the chief difficulties of the model.

Pollard, D.↗

NASA NTRS1978

Rb-Sr isochron age of the Manicouagan melt sheet, Quebec, Canada

Rb-Sr isotopic data for mineral separates from a rock of the Manicouagan impact melt sheet define an isochron of age T = 214 + or - 5 (2 sigma) m.y. which agrees with the K-Ar age of 210 + or - 8 (2 sigma) calculated by Wolfe (1971). The initial Sr-87/Sr-86 ratio I is found to be 0.70991 + or - 0.00007 (2 sigma); four whole rock samples yield age-corrected I values ranging from 0.70965 to 0.71006. These high I values support the hypothesis that the melt sheet was derived by total melting of Grenville basement rocks during the impact event 214 m.y. ago.

Jahn, B.↗

NASA NTRS1977

Petrology of Apollo 15 black-and-white rocks 15445 and 15455 - Fragments of the Imbrium impact melt sheet

The paper describes two macroscopically similar black-and-white rocks, 15445 and 15455, which were collected from the rim of Spur Crater on the Apennine Front. The two Apollo 15 rocks are very similar in chemistry and clast population, but the matrix of 15455 is finer grained than that of 15445. The 15445 sample contains a lithic clast assemblage of plutonic/metamorphic spinel troctolite, troctolite, norite, and anorthosite, and its fine-grained vesicular black coherent matrix consists of a melt-bonded aggregate of small mineral clasts which are mainly olivine, plagioclase, and pink spinel. The two rocks are distinct from any other large samples from the Apollo 15 site. It is suggested that the rocks are samples of an impact melt sheet which forms a bedrock unit of the Apennine Front, and that this melt sheet did not form in a local small-scale event but was produced during the Imbrium impact event.

Ryder, G.↗

NASA NTRS1975

The effect of local magnetic fields on the lunar photoelectron layer while the moon is in the plasma sheet

Data from the Charged Particle Lunar Environment Experiment (CPLEE), at the Apollo 14 site, are used to investigate the interactive properties of the plasma sheet and the lunar photoelectron layer. It is shown that the predictions of the Guernsey-Fu model are compatible with SIDE but not CPLEE observations. The apparent contradiction is resolved by fitting the remanent magnetic field to that of a dipole buried about 1.1 km beneath the surface. In this case a charge separation layer must form above the instrument due to the different rigidities of plasma sheet electrons and protons. The qualitative properties of the charge separation layer needed to reconcile CPLEE and SIDE observations are presented.

Burke, W. J.↗

NASA NTRS1980

Safe bending of boron/aluminum sheets

Low cost procedure utilizing aluminum backing sheets protects boron/aluminum sheet from cracking during bending. Process utilizes inexpensive universal-brake bending dies rather than special hydroforming dies.

Liskay, G. G.↗

NASA NTRS1977

Atomization of water jets and sheets in axial and swirling airflows

Axial and swirling airflows were used to break up water jets and sheets into sprays of droplets to determine the overall effects of orifice diameter, weight flow of air, and the use of an air swirler on fineness of atomization as characterized by mean drop size. A scanning radiometer was used to determine the mean drop diameter of each spray. Swirling airflows were produced with an axial combustor, 70 deg blake angle, air swirling. Water jets were injected axially upstream, axially downstream and cross stream into the airflow. In addition, pressure atomizing fuel nozzles which produced a sheet and ligament type of breakup were investigated. Increasing the weight flow rate of air or the use of an air swirling markedly reduced the spray mean drop size.

Ingebo, R. D.↗

NASA NTRS1979

Atomization of water jets and sheets in axial and swirling airflows

Ingebo, R. D.↗