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  • Other Sources  (1,368)
  • MACHINE ELEMENTS AND PROCESSES  (1,202)
  • ASTROPHYSICS
  • Humans
  • Inorganic Chemistry
  • 1970-1974  (1,368)
  • 1950-1954
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  • 1
    Publication Date: 2006-01-11
    Description: Experimental determination of the paired interaction potential of atoms and molecules composing the atmospheres of the earth and the planets is described.
    Keywords: ASTROPHYSICS
    Type: Interplanet. Medium and Phys. of the Magnetosphere (NASA-TT-F-784); p 275-281
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  • 2
    Publication Date: 2006-01-11
    Description: Research on the primary cosmic radiation and solar cosmic rays from the Luna 10, 11, and 12 artificial lunar satellites is reviewed. Data on the vertical distribution of cosmic rays above the moon's surface are presented, and the albedo for the primary radiation is determined. The fluxes of electrons with energies from 30 to 300 keV were registered in the solar cosmic rays. Rapid variations of the electron flux were observed. The angular distributions of 0.5-10 MeV protons moving together with the corpuscular streams responsible for Forbush decreases were investigated.
    Keywords: ASTROPHYSICS
    Type: Interplanet. Medium and Phys. of the Magnetosphere (NASA-TT-F-784); p 151-173
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  • 3
    Publication Date: 2006-01-11
    Description: Research on the fine structure of the interplanetary medium is reviewed. The characteristics of shock waves, filaments, and contact surfaces according to space probe measurements are discussed.
    Keywords: ASTROPHYSICS
    Type: Interplanet. Medium and Phys. of the Magnetosphere (NASA-TT-F-784); p 103-123
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  • 4
    Publication Date: 2006-01-11
    Description: The problem of quasistationary high frequency Langmuir turbulence, which is one of the types of turbulence encountered in the cosmic plasma, is examined theoretically.
    Keywords: ASTROPHYSICS
    Type: Interplanet. Medium and Phys. of the Magnetosphere (NASA-TT-F-784); p 83-102
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  • 5
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    In:  CASI
    Publication Date: 2006-01-11
    Description: Interaction studies of a plasma stream with a magnetic dipole have shown that the thickness of the plasma/field interlayer is considerably greater than the characteristic plasma dimension c/omega sub 0. Broadening of the layer is due to the formation of a collisionless shock wave. To demonstrate collisionless dissipation, the Joulean losses were calculated using the conductivity value obtained from the skin layer thickness. Analysis of the various physical processes showed that the hypothesis of collisionless dissipation of the directional plasma flow is justified.
    Keywords: ASTROPHYSICS
    Type: Interplanet. Medium and Phys. of the Magnetosphere (NASA-TT-F-784); p 59-67
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  • 6
    Publication Date: 2006-01-11
    Description: A review of experimental and theoretical studies devoted to analysis of physical processes in the magnetosphere is presented. Attention is focused on the interrelationships among the most important geophysical phenomena in the magnetosphere: magnetic storms, auroras, the radiation belts, and processes in the geomagnetic tail. Recommendations are submitted for future experiments that are needed for development of a theory of magnetospheric phenomena.
    Keywords: ASTROPHYSICS
    Type: Interplanet. Medium and Phys. of the Magnetosphere (NASA-TT-F-784); p 1-33
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  • 7
    Publication Date: 2006-01-11
    Description: Noise sources in pneumatic drills are studied bringing to light the fact that air exhaust is the most important source. The present state of the art of noise control is discussed for pneumatic percussion drills abroad, indicating the different solutions adopted in this respect. Drills produced in Rumania are described and the results of noise measurements are shown.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 177-181
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  • 8
    Publication Date: 2006-01-11
    Description: Results of experimental research on the noise and vibrations of radial ball and roller bearings are reported. Analysis of the frequency spectra disclosed dependences among vibration and noise, load, rpm and cage material. Some peculiar aspects of the frequency spectrum are also mentioned.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 131-135
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  • 9
    Publication Date: 2006-01-11
    Description: Noise sources in gears and ways of improving their silence by profile shape alterations and wheel surface smoothness are discussed. Practical results obtained, from the noise point of view are reported, for textile machinery.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 124-130
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  • 10
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    In:  CASI
    Publication Date: 2006-01-11
    Description: The influence of profile displacements on the acoustic pressure level of running gears is studied. The conclusion is reached that extra polar gears function well, reducing the acoustic pressure level by about 2-3 db which, at the level of the total noise of 80-90 db, can be easily felt. This result can be explained by the fact that in this gear the pitch point is situated outside of the gearing segment, so that a certain change in the direction of the friction force between the tooth flanks is eliminated.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 118-123
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  • 11
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    Publication Date: 2006-01-11
    Description: An original mathematical model is proposed to derive equations for calculation of gear noise. These equations permit the acoustic pressure level to be determined as a function of load. Application of this method to three parallel gears is reported. The logical calculation scheme is given, as well as the results obtained.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 112-117
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  • 12
    Publication Date: 2006-01-11
    Description: Experimental results and conclusions are presented about the noise characteristics of gears as a function of their operating conditions. The interpretive possibilities offered by real time noise and vibration spectrum analysis are emphasized. The noise reducing effects of light weight insulation boxes are also discussed.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 104-111
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  • 13
    Publication Date: 2006-01-11
    Description: A mechano-acoustic model is reported for calculating acoustic energy radiated by a working gear. According to this model, a gear is an acoustic coublet formed of the two wheels. The wheel teeth generate cylindrical acoustic waves while the front surfaces of the teeth behave like vibrating pistons. Theoretical results are checked experimentally and good agreement is obtained with open gears. The experiments show that the air noise effect is negligible as compared with the structural noise transmitted to the gear box.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 98-103
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  • 14
    Publication Date: 2006-01-11
    Description: The acoustic analysis method permits detection of any cracks that might take place and their manner of propagation. The study deals with the cracks produced in experiments to determine the welding technology for a welded gray cast iron workpiece by using piezoelectric transducers to determine vibration acceleration.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 93-97
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  • 15
    Publication Date: 2006-01-11
    Description: American equipment for drilling in the lunar surface is discussed, with emphasis on rotary-percussive methodology and core-sample retrieval techniques.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Current Concepts Regarding the Moon (NASA-TT-F-766); p 192-205
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  • 16
    Publication Date: 2011-08-16
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 37; 1, De; Dec. 197
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  • 17
    Publication Date: 2011-08-16
    Description: We have numerically studied the interaction between interstellar gas and a gravitational perturbation produced by a fluctuation in the stellar mass distribution. For a simple equation of state, shock waves develop even if the gravitational perturbation is aperiodic and transient. In a medium which can change thermal phase, shocks do not form and the gas makes a transition directly to the cold, dense phase. The cold material has an anomalous velocity imparted to it by the gravitational perturbation and it becomes an accretion front moving through the hot gas and capturing it. The accretion fronts trigger thermal phase change on a large scale and can reproduce the extent of observed cold clouds. Furthermore their high mass is favorable to gravitational instability and subsequent star formation.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 36; 2, No; Nov. 197
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  • 18
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    Publication Date: 2011-08-16
    Description: Apsidal-motion constants, k2, have been determined for models of homogeneous main-sequence stars constructed with the new 'Thomas-Fermi' opacities of Carson. These models are similar to those constructed with the 'hydrogenic' opacities of Cox and Stewart up to about 7 solar masses, but yield smaller values of k2 at higher masses. Nevertheless, the new theoretical constants are still systematically too large compared with most of the empirical constants known for members of well-observed binary systems. Uniform rotation is found to lower the theoretical constants only slightly. The effect of normal evolution during core hydrogen burning, however, produces good detailed agreement with observations. The primary of alpha Vir is probably evolving normally if Carson's opacities are adopted.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 194; Dec. 15
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  • 19
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    Publication Date: 2011-08-16
    Description: Zero-age main-sequence models for stars of 20, 10, 5, and 2 solar masses with no heavy elements are constructed for three different possible primordial helium abundances: Y=0.00, Y=0.23, and Y=0.30. The latter two values of Y bracket the range of primordial helium abundances cited by Wagoner. With the exceptions of the two 20 solar mass models that contain helium, these models are found to be self-consistent in the sense that the formation of carbon through the triple-alpha process during premain sequence contraction is not sufficient to bring the CN cycle into competition with the proton-proton chain on the ZAMS. The zero-metal models of the present study have higher surface and central temperatures, higher central densities, smaller radii, and smaller convective cores than do the population I models with the same masses.
    Keywords: ASTROPHYSICS
    Type: Astrophysics and Space Science; 31; Nov. 197
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  • 20
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    Publication Date: 2011-08-16
    Description: Determinations of interplanetary sector structure for the years 1970-1972 reveal the persistence of sector patterns during the decreasing portion of the solar cycle. The simple two-sector pattern of 1969 persists through 1970 but develops greater complexity in 1971-1972.-
    Keywords: ASTROPHYSICS
    Type: Journal of Geophysical Research; 79; Dec. 1
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  • 21
    Publication Date: 2011-08-16
    Description: Slowly rotating stars which are oscillating at small amplitude in a broad spectrum of g-modes should display strong surface nonuniformities if even weak nonlinear coupling exists between the modes. Oscillatory power will be concentrated into distinctive patterns which rotate rigidly in spite of differential rotation in the outer stellar layers. Each pattern rotates at a constant rate slower than the star as a whole according to a very simple law of rotation. Virtually all the rotation rates are within 9 per cent of the stellar rate. Evidence is cited that the sun may be oscillating, so other stars along the main sequence may be oscillating, also. If zones obeying the predicted rotation law can be detected in a star, then the rotation rate of the stellar interior becomes known, and differential rotation is negligible over most of the stellar mass.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 193; Nov. 1
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  • 22
    Publication Date: 2011-08-16
    Description: Four new interstellar lines have been detected near 87.3 GHz. Based on laboratory ESR data these lines have been positively defined as hyperfine components of the lowest rotational transition of the ethynyl radical C2H. The observations gave precise values for the C2H rotation, spin-doubling, and hyperfine constants. C2H is probably one of the most abundant interstellar polyatomic molecules yet detected.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 193; Nov. 1
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  • 23
    Publication Date: 2011-08-16
    Description: The pulsational stability of massive, chemically homogeneous stars of Population I has been investigated for a range of simple opacity representations consisting of a straight sum of electron-scattering and modified Kramers opacity. The critical mass for stability against nuclear-energized pulsations is found to be extraordinarily sensitive to small changes in the coefficient and/or temperature exponent of the absorption part of the opacity law. A gradual increase in the atomic absorption (dominant near the stellar surface) first raises the critical mass, then restricts the upper mass limit for instability, and finally eliminates pulsational instability at all masses.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 193; Nov. 1
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  • 24
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    Publication Date: 2011-08-16
    Description: Particular attention is given to the physics involved in the derivation of an equation of state for a density range from 10 g/ccm to 200,000 billion g/ccm and for the density region from 200,000 billion g/ccm to 2,000,000 billion g/ccm. Conditions in a high density regime with densities exceeding 500,000 billion g/ccm are examined. Equations of state for a gas of pure neutrons and for a gas of nucleons, electrons, and hyperons are considered.
    Keywords: ASTROPHYSICS
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  • 25
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    Publication Date: 2011-08-16
    Description: For comets whose nuclei are composed of water ice conglomerates it is shown that the ion H3O(+) can predominate to distances of 5000 km in the subsolar direction. Beyond this distance H2O(+) is the most important ion. The crossover point is a sensitive function of the rate of evaporation from the nucleus. The presence of ammonia or metals such as sodium, in concentrations greater than 0.1% H2O, can lead to NH4(+) and Na(+) ions.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 193; Oct. 1
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  • 26
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    Publication Date: 2011-08-16
    Description: Metallic line-blanketing coefficients have been measured over the wavelength range from 3800 to 4700 A in a sample of 20 Am and normal A stars. An expression for the logarithmic iron abundance has been calibrated in terms of effective temperature and a mean line-blocking coefficient. This makes it possible to determine the atmospheric iron abundance in sharp-lined Am and A stars with an accuracy of better than plus or minus 0.1 dex, using only line-blocking measurements and a photometric effective temperature.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 193; Oct. 1
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  • 27
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    Publication Date: 2011-08-16
    Description: The cross section for Li-7 production in alpha-alpha reactions is shown to be increased by about a factor of 2 due to the excitation levels of Li-7 and Be-7 at 478 keV and 431 keV, respectively. The cross section for Li-6 production, however, remains the same as calculated on the basis of the detailed balance principle. The lines at 478 keV and 431 keV may link Li-7 production to feasible gamma-ray observations.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 34; 3, Se; Sept
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  • 28
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    Publication Date: 2011-08-16
    Description: A description of the joint design, materials, equipment, qualification testing, inspection methods, and applications involved in performing induction brazing on hyperbolic propellants tubing at Kennedy Space Center. Induction brazing is a form of brazing in which the energy is transmitted to the workpiece by electrical induction; the eddy currents generated in the metal produce heat by resistance losses. Since induction heating is fast and highly localized, undesirable heat effects are minimized and the resulting braze is of high quality.
    Keywords: MACHINE ELEMENTS AND PROCESSES
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  • 29
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    Publication Date: 2011-08-16
    Description: The results of impact tests on large, fiber composite fan blades for aircraft turbofan engine applications are discussed. Solid composite blades of two different sizes and designs were tested. Both graphite/epoxy and boron/epoxy were evaluated. In addition, a spar-shell blade design was tested that had a boron/epoxy shell bonded to a titanium spar. All blades were tested one at a time in a rotating arm rig to simulate engine operating conditions. Impacting media included small gravel, two inch diameter ice balls, gelatin and RTV foam-simulated birds, as well as starlings and pigeons. The results showed little difference in performance between the graphite and boron/epoxy blades. The results also indicate that composite blades may be able to tolerate ice ball and small bird impacts but need improvement to tolerate birds in the small duck and larger category.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: SAMPE Quarterly; 5; July 197
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  • 30
    Publication Date: 2011-08-16
    Description: The use of silicone rubber adhesive (particularly, G.E. RTV-108) for sealing large leaks in high vacuum systems subject to mechanical and thermal stresses is shown to be more effective than that of epoxy cements. The sealant is applied externally to the leak while the system is partially evacuated so that it is drawn into the hole.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Journal of Vacuum Science and Technology; 11; July-Aug
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  • 31
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    Publication Date: 2011-08-16
    Description: Description of an aluminized alloy coating technique that involves first the application of a ductile, oxidation-resistant overlay, such as NiCrAl, which is then partially aluminized. The duplex protective system has performance advantages over conventional aluminide coatings in that it provides higher-temperature hot corrosion resistance over a longer service life.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Metal Progress; 106; Aug. 197
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  • 32
    Publication Date: 2011-08-16
    Description: Results of friction and thermal tests of molded polyimide and pyrrone polymers are presented. The coefficient of sliding friction up to surface velocities of 2 m/sec and the coefficient of thermal expansion from 300 to 500 K were measured. An apparatus was constructed to measure simultaneously the coefficient of sliding friction and the friction-generated temperature. Measurements were made at a nominal pressure-velocity product of 0.25 MN/msec and at temperatures between 300 and 500 K.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Polymer Engineering and Science; 14; Apr. 197
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  • 33
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    Publication Date: 2011-08-16
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  • 34
    Publication Date: 2011-08-16
    Description: The requirements involved in choosing ultrasonic devices, the factors that affect testing, and recommended calibration methods are discussed. The ultrasonic testing method is the only method that up to now permits detection of defects in welded joints of great thickness. The results are conditioned by the performances of the devices employed as well as by the degree of instruction of the personnel.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: the 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 199-203
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  • 35
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    Publication Date: 2011-08-16
    Description: On the basis of study of the electrolytic polishing of metal pieces, the following conclusions can be drawn: (1) Utilization of ultrasonically irradiated electrolytes in the electrolytic polishing of copper and steel pieces leads to enhanced polishing quality. (2) Polishing time for the reference pieces was twice as long as for the test pieces. (3) The chemical attack exerted on the surface of the test pieces in order to get the structure of the respective metal lasted less than half as long and yielded superior qualitative results in the copper as well as in the OT 60-2 steel test pieces polished with ultrasonically irradiated electrolytes. (4) The utilization of higher polishing current densities can be explained by the fact that the cavitational effect that arises in the electrolyte owing to ultrasounds contributes to an increase in the solution's electrical conductivity and elimination of gases from the electrolyte.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: the 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 210-214
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  • 36
    Publication Date: 2011-08-16
    Description: The binding energy and stability of supermassive stars (SMS's) are examined in the framework of the Parametrized Post-Newtonian (PPN) formalism of Will and Nordvedt. The PPN formalism encompasses the post-Newtonian limit of virtually every theory of gravity, differentiating between theories by means of nine PPN parameters. A general expression is derived for the energy integral in the PPN framework, and those theories in which the energy will be conserved are defined. In all such theories, a SMS of radius less than a critical radius will be unstable against adiabatic radial perturbations. Present experimental limits on the PPN parameters gamma and beta do not exclude the possibility of the existence of stable, non-rotating, hydrogen-burning SMS's of masses an order of magnitude larger than the upper limit for the mass of such stars predicted in general relativity.
    Keywords: ASTROPHYSICS
    Type: Astrophysics and Space Science; 31; Dec. 197
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  • 37
    Publication Date: 2011-08-16
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 194; Dec. 15
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  • 38
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    Publication Date: 2011-08-16
    Description: Neutral-hydrogen absorption-line interferometer observations are reported for five continuum radio sources situated behind an extensive layer of cold interstellar H I gas. In contrast to low-spatial-resolution emission-line observations reported earlier which show the large-scale uniformity of the layer, the high-spatial-resolution absorption-line observations reveal variations in the velocity and density within the layer. The new results together with the old indicate the apparent coexistence of a large-scale mechanism for triggering the formation of cold hydrogen and an instability mechanism leading to small-scale irregularities.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 194; Dec. 1
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  • 39
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    Publication Date: 2011-08-16
    Description: A neutrino mechanism is discussed in order to explain supernovae in massive stars. An argument is presented for supernova mass ejection through leptonic neutrino transport characteristics suppressed by the arbitrary zero chemical potential condition. Results show that lepton conservation effects may be important in supernova neutrino transport. At low temperature and density the diffusion approximation becomes less precise because of the long mean free paths of low energy neutrinos. The amount of equilibrium neutrino spectrum affected here is small over most of the collapsing supernova structure.
    Keywords: ASTROPHYSICS
    Type: Nature; 252; Nov. 22
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  • 40
    Publication Date: 2011-08-16
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 193; Oct. 1
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  • 41
    Publication Date: 2011-08-16
    Description: An evolutionary sequence was calculated for a white dwarf on which a hydrogen rich envelope is assumed to increase with time. The stellar models were computed by integrating numerically the system of stellar structure equations by means of the Henyey method. The accretion of matter was assumed to be quasi-static. Near the point of the chemical discontinuity, a temperature maximum is shown to arise, and hydrogen ignites; a thin shell energy source is formed which is thermally unstable. The resulting thermal runaway was investigated numerically and by means of a simple approximation based on the energy balance in the hydrogen burning shell source.
    Keywords: ASTROPHYSICS
    Type: Astrometrics and Astrophysics, No. 17 (NASA-TT-F-15768); p 1-55
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  • 42
    Publication Date: 2011-08-16
    Description: Optical parameters investigated and solved for included: (1) cloud layer albedo and cloud cover optical thickness; (2) planetary surface self-radiation influence; (3) light flux distribution as function of atmospheric height; (4) upper estimate of the observed contrasts; (5) surface optical parameters; and (6) contrast decrease with altitude.
    Keywords: ASTROPHYSICS
    Type: Space Iconics (NASA-TT-F-798); p 121-135
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  • 43
    Publication Date: 2011-08-16
    Description: Several methods using an approximate form of the scattering indicatrix are discussed for simplifying the calculation of radiation transport in planetary atmospheres.
    Keywords: ASTROPHYSICS
    Type: Space Iconics (NASA-TT-F-798); p 75-84
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  • 44
    Publication Date: 2011-08-16
    Description: The methods for monitoring the presence of foreign bodies in radio electronic equipment are discussed. Descriptions of the structural design under the operating principle of the device for detecting foreign bodies weighing to 0.0026 grams are given.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 100-102
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  • 45
    Publication Date: 2011-08-16
    Description: Peculiarities are described of the manufacturing process and the control of elements of slit collimators, the structural design of the required equipment and the process or assembling the collimators.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 89-91
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  • 46
    Publication Date: 2011-08-16
    Description: A method follows for applying a mirror reflecting layer to the surfaces of parts, instruments, apparatus, and so on. A brief analysis is presented of the existing methods of obtaining the mirror surface and the advantages of the new method of obtaining the mirror surface by polymer casting mold are indicated.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 84-88
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  • 47
    Publication Date: 2011-08-16
    Description: The small module geared coupling of an undulatory transmission is considered. Versions of the manufacture of gears with internal coupling and the instruments and equipment used, are reported.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 77-79
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  • 48
    Publication Date: 2011-08-16
    Description: The process of manufacturing grids, the peculiarities of the structural design, the fittings, the requirements on the tools and work area are discussed.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 80-83
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  • 49
    Publication Date: 2011-08-16
    Description: The average labor of individual types of operations in the percentage ratio of the total labor consumption of manufacturing scientific instruments and apparatus for space research is presented. The prospective areas in the production technology of billet, machining, mechanical assembly, installation and assembly, adjustment and regulation and testing and control operations are noted. Basic recommendations are made with respect to further reduction of labor consumption and an increase in the productivity of labor when manufacturing scientific equipment for space research.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 69-76
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  • 50
    Publication Date: 2011-08-16
    Description: The development of a potentiometric servosystem is described that has a dc microservomotor, which is the built in drive of an undulatory reducing gear. The operation of the system and the structural design of the undulatory reducing gear are elaborated. Results are presented from analyzing some tests of various types of undulatory reducing gear generators.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Technol. for the Production of Space Equipment (NASA-TT-F-15766); p 44-53
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  • 51
    Publication Date: 2011-08-16
    Description: A study was made of the efficiency of solid lubricating coatings, based on MoS2 with various binders, during friction and under highvacuum conditions. Mass spectrometry was used for an analysis of the composition of the gas evolved from the coatings in the friction process. It is shown that the vacuum level, loading, and sliding velocity influence coating effectiveness. In the friction process the solid lubricant coatings yield characteristic decay products associated with the chemical nature of the binders. The mechanism of coating breakdown during friction is associated with the binder breakdown mechanism.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Space Studies in the Ukraine, No. 1 (NASA-TT-F-15535); p 99-112
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  • 52
    Publication Date: 2011-08-16
    Description: A brief review of studies on low-temperature friction are briefly reviewed. A facility and technique for studying friction both in air and in vacuum at temperatures of +20 and -190 C is described. Results of a wear study of structural steels operating together with chromium steel are presented. It is shown that reduction of the test temperature in vacuum leads in certain cases to marked increase of the wear magnitude and friction coefficient. This is associated not only with the general change of the mechanical properties of the materials but also with the influence of temperature reduction on the hardening and structural formation taking place in the surface layers during friction.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Space Studies in the Ukraine, No. 1 (NASA-TT-F-15535); p 65-75
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  • 53
    Publication Date: 2011-08-16
    Description: The solar spectrum at the surface of the earth is analyzed. A facility for creating concentrated solar radiant energy flux is described, and data on its energetic capabilities are presented. The technology of solar welding by the fusion technique and joining by high-temperature brazing is examined. The use of concentrated solar radiant energy for welding and brazing metals and alloys is shown. The results of mechanical tests and microscopic and macroscopic studies are presented.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Space Studies in the Ukraine, No. 1 (NASA-TT-F-15535); p 9-18
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  • 54
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    Publication Date: 2011-08-16
    Description: The basic aspect of parallel-surface lubrication that distinguishes it from other areas of lubrication technology is that classical lubrication theory does not predict the existence of a stable hydrodynamic film for steady-state, isothermal, incompressible flow between smooth, parallel surfaces. Hydrodynamic films between apparently parallel surfaces have been observed in practice and are often essential for the reliable performance of thrust bearings and seals. In order to account for this fortunate discrepancy between classical theory and experiment, load-support mechanisms relating to accidential features characteristic of seal performance, which relax one or more of the assumptions in the classical theory and permit the theoretical prediction of load support are proposed. Some of the features that have been analyzed are vibratory effects such as wobble and bounce, surface waviness, nonsymmetric rotation resulting from various types of misalignment, lubricant density change, non-Newtonian lubricant effects, and surface roughness.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NBS The Role of Cavitation in Mech. Failures; p 77-87
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  • 55
    Publication Date: 2011-08-16
    Description: The criteria for the stability of the subharmonic, harmonic, or superharmonic oscillations determine the relation between acoustic field parameters and particle parameters. The derived formulas underlie the destruction of the fragile Widmanstatten structure in weldings and therefore the designing of the generators that must be used for this welding process.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 131-138
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  • 56
    Publication Date: 2011-08-16
    Description: The exposure of saturated hydrocarbons to ultrasound (800 kHz, 6 W/sq cm) in the presence of water results in: (1) cleavage of the carbon chain, producing saturated and unsaturated hydrocarbons with a lower number of carbons than the initial hydrocarbon (cracking); and (2) recombination after cleavage, producing saturated and unsaturated hydrocarbons with a higher number of carbons than the initial hydrocarbon (reformation). The addition of argon facilitates these phenomena. The effects are attributed to a homolytic (radical) mechanism occurring within the cavitation bubbles under the effects of microsparks.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 139-147
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  • 57
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    Publication Date: 2011-08-16
    Description: The results of an investigation indicate the following: (1) The deposition of incrustations on the heating surfaces of steam boilers can be prevented by inserting between heating surface and water an insulating layer on which the boiler incrustation will be deposited. (2) The insulating layer reduces the coefficient of heat transmission by 2%. (3) The insulating layer can be removed by macrosounds with a frequency of about 20 kHz, after any interval of boiler operation.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 126-130
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  • 58
    Publication Date: 2011-08-16
    Description: During the treatment of an electric welding arc with ultrasonic oscillations, an improvement was found in overall source-arc stability. Theoretical explanations are provided for this phenomenon and formulas of equivalence between the classical arc and the treated arc are derived, taking stability as their criterion. A knowledge of this phenomenon can be useful in extending the applications of ultrasounds to different forms of electric arcs.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 118-125
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  • 59
    Publication Date: 2011-08-16
    Description: Electrographic imagery of Comet Kohoutek in the 1100-1500 A wavelength range was obtained from a sounding rocket on Jan. 8, 1974, and from the Skylab space station on 13 occasions between Nov. 26, 1973 and Feb. 2, 1974. These images are predominantly due to Lyman-alpha (1216 A) emission from the hydrogen coma of the comet. The rocket pictures have been calibrated for absolute sensitivity and a hydrogen production rate has been determined. However, the Skylab camera suffered degradation of its sensitivity during the mission, and its absolute sensitivity for each observation can only be estimated by comparison of the comet images with those taken by the rocket camera, with imagery of the geocoronal Lyman-alpha glow, of the moon in reflected Lyman-alpha, and of ultraviolet-bright stars. The rocket and geocoronal comparisons are used to derive a preliminary, qualitative history of the development of the cometary hydrogen coma and the associated hydrogen production rate.
    Keywords: ASTROPHYSICS
    Type: Icarus; 23; Dec. 197
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  • 60
    Publication Date: 2011-08-16
    Description: The appearance of a 'sunward' spike, opposite in apparent orientation to the normal Type-II tail in Comet Kohoutek is interpreted as evidence for large particles ejected near perihelion. It is shown that the shape and orientation can be satisfactorily explained in this manner, after consideration of the increased mass flow at decreasing heliocentric distance. The apparent length of the spike can be a measure of the particle size and density, and a value of about 0.004 g/sq cm for the product of particle size and density fits the Skylab observations.
    Keywords: ASTROPHYSICS
    Type: Icarus; 23; Dec. 197
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  • 61
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    Publication Date: 2011-08-16
    Description: It is pointed out that excited states of He-4 cannot produce gamma ray line emission of astrophysical significance, contrary to a recent suggestion of Reina et al. (1974). The only possible gamma-ray lines in He-4 are above 25 MeV, but their excitation cross sections appear to be so small that they are probably of little astrophysical significance.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 36; 2, No; Nov. 197
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  • 62
    Publication Date: 2011-08-16
    Description: A systematic study is made of the number and types of solutions of the equilibrium equations of stellar structure, in the case of homogeneous stars of Population I over the mass range 2-1000 solar masses, with four different opacity representations. A variant of the usual fitting method permits the simultaneous investigation of convergence and tendency toward multiplicity of the solutions. Quadratic interpolation and extrapolation of Carson's new opacity tables produces a very large opacity at low temperatures that greatly affects the loose outer layers of massive stars, while leaving the cores practically unaffected. As a result, over a small mass range, well above 100 solar masses, triple solutions exist, always near an effective temperature of log Te = 4.73. A simple classification of the known exceptions to the Vogt-Russell theorem on the uniqueness of stellar structure is given.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 194; Dec. 15
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  • 63
    Publication Date: 2011-08-16
    Description: Neutrino pair emission from stellar interiors is investigated. The paper indicates that the proposed enhanced emission mode is a part of a transverse mode spectrum with a refraction index in the limit of infinity. It is concluded that in an astrophysical sense a very strong magnetic field does not have a significant effect on the emission rate of neutrinos from plasmons.
    Keywords: ASTROPHYSICS
    Type: Astrophysics and Space Science; 31; Nov. 197
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  • 64
    Publication Date: 2011-08-16
    Keywords: ASTROPHYSICS
    Type: Nature; 252; Dec
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  • 65
    Publication Date: 2011-08-16
    Description: A spectrometer was used on the satellite Copernicus to observe a chromospheric L alpha emission from the K0 giant beta Gem at 1218.4 A. This emission appears to be in the corona at temperatures near 260,000 deg K, since the ion it is identified with requires 77.4 eV to be produced.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 193; Nov. 1
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  • 66
    Publication Date: 2011-08-16
    Description: On the basis of a consideration of the rotation constant and the hyperfine structure together with the results of an ab initio structural calculation it is suggested that the three closely space new interstellar lines near 93.174 GHz reported by Turner (1974) might have been produced by the molecular ion N2H(+). It is pointed out that the identification of N2H(+) is reasonable also in terms of current ideas of interstellar chemistry.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 193; Oct. 15
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  • 67
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    Publication Date: 2011-08-16
    Description: A series of active cavity radiometers (ACRs) are described which have been developed as standard detectors for the accurate measurement of irradiance in absolute units. It is noted that the ACR is an electrical substitution calorimeter, is designed for automatic remote operation in any environment, and can make irradiance measurements in the range from low-level IR fluxes up to 30 solar constants with small absolute uncertainty. The instrument operates in a differential mode by chopping the radiant flux to be measured at a slow rate, and irradiance is determined from two electrical power measurements together with the instrumental constant. Results are reported for measurements of the solar constant with two types of ACRs. The more accurate measurement yielded a value of 136.6 plus or minus 0.7 mW/sq cm (1.958 plus or minus 0.010 cal/sq cm per min).
    Keywords: ASTROPHYSICS
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  • 68
    Publication Date: 2011-08-16
    Description: Observations of nonthermal continuum radio emission at 750 MHz and hydrogen-line emission at 1420 MHz have been compared in order to test the extent to which cosmic-ray electrons, magnetic fields, and hydrogen gas coexist in the interstellar medium. If the interstellar medium is homogeneous in the sense that its constituents are mixed together and can interact, then regions of line and continuum emission should be spatially correlated. The measurements indicate that at most 28% of continuum emission in the Galaxy comes from such a homogeneous medium. The remaining nonthermal emission agrees in magnitude with the residual emission found by Berkhuijsen after subtraction of the polarized component of nonthermal emission. In addition, the data discussed here show that the major filamentary structures found in the two forms of emission rarely coincide spatially. Consequently, both the average and the exceptional structure in the medium indicate that the synchrotron-radiating magnetoplasma and the neutral hydrogen gas are not closely interacting in the present state of the medium.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 194; Dec. 1
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  • 69
    Publication Date: 2011-08-16
    Description: Consistent data for more than 8 years have been obtained from two identical cosmic dust particle experiments on board the space probes Pioneer 8 and 9. The two spacecraft are in direct heliocentric orbits with perihelia between 0.75 AU and 1.00 AU. On the basis of the data it is concluded that the majority of dust particles having elliptical orbits detected by the two space probes show orbital characteristics of Apollo group asteroids which originated from residual nuclei of short-period comets.
    Keywords: ASTROPHYSICS
    Type: Nature; 252; Dec. 13
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  • 70
    Publication Date: 2011-08-16
    Description: It is pointed out that many space-manufacturing processes will require the manipulation of weightless molten material within a container in such a way that the material does not touch the container wall. A description is given of an acoustical method which can be used for the positioning and shaping of any molten material including nonconductors such as glasses. The new approach makes use of an acoustical standing wave which is excited within an enclosure or resonator.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Astronautics and Aeronautics; 12; July-Aug
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  • 71
    Publication Date: 2011-08-16
    Description: The use of Auger electron spectroscopy (AES) to search for transferred polymer must contend with the fact that there has been no published work on Auger analysis of polymers. Since this is a new area for AES, the Auger spectra of polymers and of halogenated polymers in particular is discussed. It is shown that the Auger spectra of halogenated polymers have certain characteristics that permit an assessment of whether a polymeric transfer film has been established by sliding contact. The discussion is general and the concepts should be useful in considering the Auger analysis of any polymer. The polymers chosen for this study are the halogenated polymers polytetrafluoroethylene (PTFE), polyvinyl chloride (PVC), and polychlorotrifluorethylene (PCTFE).
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Journal of Applied Physics; 45; July 197
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  • 72
    Publication Date: 2011-08-16
    Description: Woodworking often requires the wood to be bent into different shapes. In view of the fact that macrosonic waves compress and expand the medium through which they are being propagated we assumed that wood subjected to the action of these waves during the bending process would have enhanced plasticity as a result of the loosening-up that takes place in it, as well as of the reduction in effort. To this effect, the bending of wood plasticized in a macrosonic field was studied. This bending took place under good conditions, and structural analyses conducted with the aid of an electron microscope proved initial premises to be corrent. Applied on an industrial scale, this procedure would contribute to improving the technology of wood bending as well as to eliminating factory spoilage.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 234-237
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  • 73
    Publication Date: 2011-08-16
    Description: The results are discussed which were obtained with a new method of desorption of collector reagents connected with improving the selectivity of the flotation of copper and lead concentrate through the action of ultrasounds. Analysis of the results obtained by treating copper and lead concentrate in an ultraacoustic field indicates an increase in the copper content of the copper concentrate, of the lead content in the lead concentrate and, at the same time, a reduction in the lead of the copper concentrate.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics Vol. 2, B (NASA-TT-F-15663); p 112-117
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  • 74
    Publication Date: 2011-08-16
    Description: In the case of macrosonic drawing, it was experimentally determined that tube eccentricity is less than in the case of tube drawing without macrosonics. On this basis, a theoretical analysis was carried out of the effect of macrosounds on tube eccentricity, an analysis that qualitatively confirms the experimental data.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-15663); p 102-111
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  • 75
    Publication Date: 2011-08-16
    Description: The results are discussed of studies of the influence of macrosounds on a metal's friction and deformation conditions at the focus of deformation, on the mechanical characteristics of cold-drawn tubes, and on the dynamic stability of the focus of deformation. In the course of these studies, experimental equipment was developed and perfected. Under the proposed conditions the cold drawing of tubes on an ultrasonically activated plug turned out to be viable and efficient.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 89-96
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  • 76
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    Publication Date: 2011-08-16
    Description: An investigation was conducted to extend the technology of powder product manufacturing to new forms and sizes, to improve their quality as well as pressing efficiency and to reduce waste. In the course of metal and nonmetal powder briquette pressing, macrosounds were associated with the external static pressing force, which led to an increase in the relative height, density and physicomechanical characteristics of the briquettes. This method permits the extension of the range of products that can be manufactured from powders and the improvement of their quality.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics, Vol. 2, B (NASA-TT-F-15663); p 77-83
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  • 77
    facet.materialart.
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    Publication Date: 2011-08-16
    Description: The application of ultrasonic radiation for metal working of steel is discussed. It is stated that the productivity of the ultrasonic working is affected by the hardness of the material to be worked, the oscillation amplitude, the abrasive temperature, and the grain size. The factors that contribute to an increase in the dislocation speed are analyzed. Experimental data are provided to substantiate the theoretical parameters.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics Vol. 2, B (NASA-TT-F-15663); p 60-66
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  • 78
    facet.materialart.
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    Publication Date: 2011-08-16
    Description: Problems in the industrial application of ultrasounds are discussed. Starting from the industrial characteristics of ultrasonic working, especially of hard and fragile materials that are difficult to work by means of conventional methods, the characteristics of the feed system, the circulation system of the abrasive suspension, and the ultra-acoustic unit of machines for ultrasonic working are described. Experiments on the behavior of different types of ultra-acoustic unit design and on the optimal operating conditions connected with the manner of execution, fixation, and excitation conditions are analyzed.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: The 4th Natl. Conf. on Acoustics Vol. 2, B (NASA-TT-F-15663); p 53-59
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  • 79
    facet.materialart.
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    In:  CASI
    Publication Date: 2016-06-07
    Description: Candidate space missions to study the temperature profiles, and ratios of hydrogen to helium in outer planet atmospheres are discussed in terms of scientific payloads for optical occultation, radio occultation, and thermometer measurements.
    Keywords: ASTROPHYSICS
    Type: Dynatrend, Inc. Proc. of Outer Planet Probe Technol. Workshop, Sect. 1 through 11; 8 p
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  • 80
    Publication Date: 2016-06-07
    Description: Near infrared ice band measurements, radar and radio observations, and implications of the size estimates of particles in Saturn's rings are discussed. The measurements are compared to the Poynting-Robetson effect and a possible mechanism by which the size of the particles may significantly change after the initial formulation of the material in the rings is proposed.
    Keywords: ASTROPHYSICS
    Type: The Rings of Saturn; p 107-123
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  • 81
    facet.materialart.
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    In:  CASI
    Publication Date: 2016-06-07
    Description: Outgassing of H and OH from Saturn's rings and the possibility of detecting it are examined. The source gas around the rings is computed after which the products of ice, H2O, H, and OH and the physical mechanisms that produce these species are given. Production rates for the ice products are discussed.
    Keywords: ASTROPHYSICS
    Type: NASA, Washington The Rings of Saturn; p 125-129
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  • 82
    Publication Date: 2016-06-07
    Description: A 64m radar antenna was used to observe Saturn's rings at 12.6 cm wavelength, with reduced Doppler spread. The results show a positive radar return corresponding to about a 60 percent return from an isotropic scatterer with the projected area of the rings, allowing for the Cassini division. A radar spectrogram of the rings is shown with power density plotted against Doppler frequency shift.
    Keywords: ASTROPHYSICS
    Type: NASA, Washington The Rings of Saturn; p 73-82
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  • 83
    Publication Date: 2016-06-07
    Description: After adjusting for the decreased Sun-Saturn distance and adjusting all measurements to B ring values only, it is shown that the temperature variations are not as large as was thought. Various models of the multilayer agglomerate of particles of Saturn's rings are evaluated. It is recommended that the difference between the 11 and 20 micron brightness temperatures should be explained by a satisfactory model.
    Keywords: ASTROPHYSICS
    Type: NASA, Washington The Rings of Saturn; p 65-72
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  • 84
    facet.materialart.
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    In:  CASI
    Publication Date: 2016-06-07
    Description: Spacecraft design is discussed for probing Saturn's rings. Ring particles are also considered, emphasizing material outside of ring A and the hazard this might imply to a spacecraft crossing the ring plane beyond ring A.
    Keywords: ASTROPHYSICS
    Type: NASA, Washington The Rings of Saturn; p 29-38
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  • 85
    Publication Date: 2016-06-07
    Description: The probable chemistry of the Saturn rings is reviewed. Reflectance spectra for H20 and NH3 frosts and Saturn's rings are compared, along with temperature dependence of 1.6 microns water frost feature. The reflection spectra of Galilean satellite J2 and water frost are also reviewed.
    Keywords: ASTROPHYSICS
    Type: NASA, Washington The Rings of Saturn; p 51-63
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  • 86
    Publication Date: 2016-06-07
    Description: The effects of multiple anisotropic scattering were calculated, including the solar penumbra effect for shadowing computations. The classical model was matched to observations, including the wavelength dependence, by varying the particle albedo as a function of wavelength. A scattering diagram is also presented showing the relative amount of primary and higher-order scattering necessary to match the B ring brightness and the shape of the phase curve.
    Keywords: ASTROPHYSICS
    Type: NASA, Washington The Rings of Saturn; p 17-28
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  • 87
    Publication Date: 2016-06-07
    Description: The photometric phase curves of Saturn's rings are considered, as well as a conflict between dynamical and photometric models of the rings. The dependence of ring brightness on angular separation of the earth and sun as viewed from Saturn is discussed. The nonlinear brightness surge is interpreted. Some quantitative calculations were carried out for bodies in and near the asteroidal belt. Predicted density profiles of the ring obtained with Mimas in an eccentric orbit and in a circular orbit are also included.
    Keywords: ASTROPHYSICS
    Type: NASA, Washington The Rings of Saturn; p 3-15
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  • 88
    Publication Date: 2019-01-25
    Description: The unique conditions offered by the earth orbital environment in material processing involving both solid and liquid phases, such as liquid phase sintering, were studied. An experimental development program involving both test and theoretical work was initiated. Experimental work using material combinations selected such that maximum information about the effect of gravity can be derived has been conducted. Wetting of the solid phase by the liquid during sintering is an important phenomenon in liquid phase sintering, and gravity has influence on both capillary phenomenon and density segregation; hence, material combinations were selected such that these two effects can be suitably studies. The experimental work is meant to form the basis for similar comparative work done under low-g conditions. The part of the model dealing with the capillary phenomenon, as related to liquid phase sintering and the effect of gravity on it, suggest that gravity will have negligible effect on the Bond number and that the cohesive force is dependent on both the amount of liquid phase and the angle of contact.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: Proc. of the 3d Space Processing Symp. on Skylab Results, Vol. 2; p 963-1001
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  • 89
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    Publication Date: 2019-01-25
    Description: The non-contact positioning of materials in a space processing chamber is accomplished using a new type of acoustic levitator. Liquid and solid materials are positioned using a single source of sound. Fine control of position may be obtained by motion of an acoustical reflector. Electrical power required is usually less than 100 watts. The system operates satisfactorily at high and low temperatures and is adaptable as an add-on feature to existing space experiments. Containerless melting and solidification can be performed and a freely suspended liquid can be shaped to the contour of the sound field. Experiments are described in which aluminum, glass and plastic materials are melted and solidified in the containerless state. The system has applications to containerless crystal growth, melting and related processes.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA. Marshall Space Flight Center Proc. of the 3d Space Processing Symp. on Skylab Results, Vol. 2; p 647-677
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  • 90
    Publication Date: 2019-01-25
    Description: By readily levitating, positioning, and manipulating materials placed in it, the acoustical resonator can serve a variety of space processing operations, such as drawing crystals, degassing, and stirring of melts, and casting.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA. Marshall Space Flight Center Proc. of the 3d Space Processing Symp. on Skylab Results, Vol. 2; p 679-690
    Format: text
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  • 91
    Publication Date: 2019-01-25
    Description: The design constraints for orbiting materials processing systems are dominated by the limitations of the flight vehicle/crew and not by the processes themselves. Although weight, size and power consumption are all factors in the design of normal laboratory equipment, their importance is increased orders of magnitude when the equipment must be used in an orbital facility. As a result, equipment intended for space flight may have little resemblance to normal laboratory apparatus although the function to be performed may be identical. The same considerations influence the design of the experiment itself. The processing requirements must be carefully understood in terms of basic physical parameters rather than defined in terms of equipment operation. Preliminary experiments and analysis are much more vital to the design of a space experiment than they are on earth where iterative development is relatively easy. Examples of these various considerations are illustrated with examples from the M518 and MA-010 systems. While these are specific systems, the conclusions apply to the design of flight materials processing systems both present and future.
    Keywords: MACHINE ELEMENTS AND PROCESSES
    Type: NASA. Marshall Space Flight Center Proc. of the 3d Space Processing Symp. on Skylab Results, Vol. 2; p 595-601
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  • 92
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    Unknown
    In:  CASI
    Publication Date: 2016-06-07
    Keywords: ASTROPHYSICS
    Type: JPL Proc. of the Intern. Colloq. on Drops and Bubbles, Vol. 1; p 11-34
    Format: application/pdf
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  • 93
    facet.materialart.
    Unknown
    In:  CASI
    Publication Date: 2016-06-07
    Keywords: ASTROPHYSICS
    Type: JPL Proc. of the Intern. Colloq. on Drops and Bubbles, Vol. 1; p 1-10
    Format: application/pdf
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  • 94
    Publication Date: 2019-06-27
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 36; 3, De; Dec. 197
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  • 95
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    Unknown
    In:  Other Sources
    Publication Date: 2019-06-27
    Description: Stellar winds from a binary star will interact with each other along a contact discontinuity. We discuss qualitatively the geometry of the flow and field resulting from this interaction in the simplest case where the stars and winds are identical. We consider the shape of the critical surface (defined as the surface where the flow speed is equal to the sound speed) as a function of stellar separation and the role of shock waves in the flow field. The effect of stellar spin and magnetic sectors on the field configuration is given. The relative roles of mass loss and magnetic torque in the evolution of orbital parameters are discussed.
    Keywords: ASTROPHYSICS
    Type: Astrophysics and Space Science; 31; Dec. 197
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  • 96
    Publication Date: 2019-06-27
    Description: A search was conducted for the three 9-cm transitions of the ground state Lambda-doublet of CH in comet Kohoutek, using the CSIRO 64-m radio telescope and the Onsala Space Observatory's 25.6-m telescope. No lines were detected during the observing periods, and upper limits are given for the corresponding antenna temperatures.
    Keywords: ASTROPHYSICS
    Type: Icarus; 23; Dec. 197
    Format: text
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  • 97
    Publication Date: 2019-06-27
    Description: Nine transitions of the possible parent molecules H2O, NH3, CH3OH and N2O as well as the OH radical were searched for in Comet Kohoutek (1973f) in the frequency range 22.2-25.2 GHz. These molecules were not detected, but the upper limits for the optical depth, mean column density and the production rate are derived for each of the molecules. These results are discussed and compared with the reported detections of HCN and CH3CN emission and OH absorption.
    Keywords: ASTROPHYSICS
    Type: Icarus; 23; Dec. 197
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  • 98
    Publication Date: 2019-06-27
    Description: The model derived for the anti-tail of Comet Kohoutek describes it as a flat formation, confined essentially to the comet's orbit plane and composed of relatively heavy particles (mostly in the size range 0.1-1 mm) whose motions are controlled by solar gravity and solar radiation pressure. Almost all the material was produced by the comet before perihelion at a rate about an order of magnitude higher than for Comets Arend-Roland and Bennett. The latent heat of vaporization of the particle material is estimated at 40-45 kcal/mole or higher.
    Keywords: ASTROPHYSICS
    Type: Icarus; 23; Dec. 197
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  • 99
    Publication Date: 2019-06-27
    Description: An upper limit on the rate of evolution of CO from Comet Kohoutek has been obtained from a search for resonant scattering of sunlight near 4.7 microns. The observations were made approximately two months after perihelion. The rate of evolution of CO at that time was apparently less than that of CH3CN observed before perihelion.
    Keywords: ASTROPHYSICS
    Type: Icarus; 23; Dec. 197
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  • 100
    facet.materialart.
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    In:  Other Sources
    Publication Date: 2019-06-27
    Description: With two f-values of C I lines obtained from the spectra of zeta Pup and gamma(2) Vel, it is shown that the interstellar C I spectrum in zeta Oph obeys an optical-depth relation similar to that for Na I, and the relative strengths of 19 multiplets are determined from this relation. The dominant processes which excite neutral carbon are used to calculate populations of the fine-structure levels as functions of the density of H nuclei and the temperature, and evidence is found that the C I lines are formed in the dense cloud in front of zeta Oph at a heliocentric velocity of -14.4 km/s. It is noted that the observed column-density ratios of the neutral carbon fine-structure levels lead to a total H nuclei density of about 220 to 660 per cu cm, while the electron density and observed C(+) abundance indicate a value of 10,000 per cu cm, with a 0.05 pc thick gas layer.
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 37; 2, De; Dec. 197
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