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  • Other Sources  (1,369)
  • FLUID MECHANICS  (1,203)
  • ASTROPHYSICS
  • Animals
  • Humans
  • Inorganic Chemistry
  • 1970-1974  (1,369)
Collection
Source
Keywords
Years
Year
  • 1
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    Short-range repulsive forces between atoms and molecules of atmospheric gases (1974)
    In:  CASI
    Details
    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
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    An investigation of the cosmic radiation in the vicinity of the moon on the Luna 10, 11, and 12 artificial lunar satellites (1974)
    In:  CASI
    Details
    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
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    Structural formations in the interplanetary medium (1974)
    In:  CASI
    Details
    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
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    High-frequency turbulence in the cosmic plasma (1974)
    In:  CASI
    Details
    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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    Dissipation of energy in model experiments (1974)
    In:  CASI
    Details
    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
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    Certain problems in the physics of the magnetosphere (1974)
    In:  CASI
    Details
    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
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    The Coanda effect in gas-dynamic noise control (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: The principle types of silencers are discussed for gas dynamic noise of free steam and gas expansions, as well as the results of research in gas dynamics of jets and applied acoustics. Gas dynamic noise attenuation by means of the Coanda effect is due to fluid decompression in a Coanda ejector of the external type, where a structural change takes place in the acoustic frequency spectrum and in its direction, as well as a substantial decrease in the fluid's velocity, temperature and concentration. This process is continued in the second phase with absorption of the acoustic waves by means of an active structure.
    Keywords: FLUID MECHANICS
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 143-149
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  • 8
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    Neutron stars with main sequence binary companions as low luminosity X-ray sources (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 37; 1, De; Dec. 197
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  • 9
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    The interaction of interstellar gas with stellar density wave packets (1974)
    In:  Other Sources
    Details
    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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  • 10
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    The Apsidal-motion test for models of main-sequence stars (1974)
    In:  Other Sources
    Details
    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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  • 11
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    Main sequence models for massive zero-metal stars (1974)
    In:  Other Sources
    Details
    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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  • 12
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    Interplanetary sector structure - 1970-1972 (1974)
    In:  Other Sources
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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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  • 13
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    Distinctive patterns on the surface of slowly rotating stars whose oscillations are nonlinearly coupled (1974)
    In:  Other Sources
    Details
    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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  • 14
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    The ethynyl radical C2H - A new interstellar molecule (1974)
    In:  Other Sources
    Details
    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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  • 15
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    Influence of opacity on the pulsational stability of massive stars with uniform chemical composition. II - Modified Kramers opacity (1974)
    In:  Other Sources
    Details
    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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  • 16
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    Equation of state at ultrahigh densities. I (1974)
    In:  Other Sources
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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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  • 17
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    Cometary coma ions (1974)
    In:  Other Sources
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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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  • 18
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    An empirical line-blanketing study of Am stars (1974)
    In:  Other Sources
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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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  • 19
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    Li production in alpha-alpha reactions (1974)
    In:  Other Sources
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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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  • 20
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    New diagnostic technique for the study of turbulent boundary-layer separation (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Description of a diagnostic technique for determining the unsteady character of turbulent boundary-layer separation. The technique uses thin platinum films mounted flush with the model surface. Voltages from these films provide measurements related to the flow character above the film. For illustration, results obtained by this technique are presented for the interaction of a hypersonic shock wave and a turbulent boundary layer, with and without separation.
    Keywords: FLUID MECHANICS
    Type: AIAA Journal; 12; Oct. 197
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  • 21
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    Reynolds-shear-stress measurements in a compressible boundary layer within a shock-wave-induced adverse pressure gradient (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: FLUID MECHANICS
    Type: Journal of Fluid Mechanics; 65; Aug. 12
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  • 22
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    Evolution of a moderately short turbulent boundary layer in a severe pressure gradient (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The early and intermediate development of a highly accelerated (or decelerated) turbulent boundary layer is analyzed. For sufficiently large accelerations (or pressure gradients) and for total normal strains which are not excessive, the equation for the Reynolds shear stress simplifies to give a stress that remains approximately constant as it is convected along streamlines. The theoretical results for the evolution of the mean velocity in favourable and adverse pressure gradients agree well with experiment for the cases considered. A calculation which includes mass injection at the wall is also given.
    Keywords: FLUID MECHANICS
    Type: Journal of Fluid Mechanics; 64; July 24
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  • 23
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    Turbulent diffusion with memories and intrinsic shear (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The first part of the present theory is devoted to the derivation of a Fokker-Planck equation. The eddies smaller than the hydrodynamic scale of the diffusion cloud form a diffusivity, while the inhomogeneous, bigger eddies give rise to a nonuniform migratory drift. This introduces an eddy-induced shear which reflects on the large-scale diffusion. The eddy-induced shear does not require the presence of a permanent wind shear and is intrinsic to the diffusion. Secondly, a transport theory of diffusivity is developed by the method of repeated-cascade and is based upon a relaxation of a chain of memories with decreasing information. The full range of diffusion consists of inertia, composite, and shear subranges, for which variance and eddy diffusivities are predicted. The coefficients are evaluated. Comparison with experiments in the upper atmosphere and oceans is made.
    Keywords: FLUID MECHANICS
    Type: Zeitschrift fuer Naturforschung; vol. 29a
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  • 24
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    On numerical methods to impose asymptotic boundary conditions of boundary-layer equations (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The error minimization method proposed by Nachtsheim and Swigert (1965) to satisfy the asymptotic boundary conditions of boundary layer equations is proved to be equivalent to imposing the condition of fastest decay. As a consequence, a uniqueness problem is not arising in the solutions of boundary layer equations obtained by their method.
    Keywords: FLUID MECHANICS
    Type: Computers and Fluids; 2; Mar. 197
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  • 25
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    Method for producing a uniform, low Reynolds number jet (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: In one attempt to produce a simple inexpensive nozzle, a 2-in. diam plate with 37 holes was investigated (Stadler, 1960), anticipating that the small jets emanating from the plate would combine to form a uniform stream. This experiment was unsuccessful because a uniform flow was not established until the flow had progressed many nozzle diameters downstream. However, an extension of this concept to a much larger number of very small jets, viz., a porous plate, did provide a method for producing a uniform, low Reynolds number jet almost immediately downstream of the nozzle (Greene, 1973). The method is described and some typical jet velocity profiles for nozzle Reynolds numbers from 50 to 1000 are given.
    Keywords: FLUID MECHANICS
    Type: Journal of Spacecraft and Rockets; 11; Aug. 197
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  • 26
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    Approach to the origin of turbulence on the basis of two-point kinetic theory (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Equations for the fluctuation correlation in an incompressible shear flow are derived on the basis of kinetic theory, utilizing the two-point distribution function which obeys the BBGKY hierarchy equation truncated with the hypothesis of 'ternary' molecular chaos. The step from the molecular to the hydrodynamic description is accomplished by a moment expansion which is a two-point version of the thirteen-moment method, and which leads to a series of correlation equations, viz., the two-point counterparts of the continuity equation, the Navier-Stokes equation, etc. For almost parallel shearing flows the two-point equation is separable and reduces to two Orr-Sommerfeld equations with different physical implications.
    Keywords: FLUID MECHANICS
    Type: Physics of Fluids; 17; Jan. 197
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  • 27
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    Computation of steady nozzle flow by a time-dependent method (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The equations of motion governing steady, inviscid flow are of a mixed type, that is, hyperbolic in the supersonic region and elliptic in the subsonic region. These mathematical difficulties may be removed by using the so-called time-dependent method, where the governing equations become hyperbolic everywhere. The steady-state solution may be obtained as the asymptotic solution for large time. The object of this research was to develop a production type computer program capable of solving converging, converging-diverging, and plug two-dimensional nozzle flows in computational times of 1 min or less on a CDC 6600 computer.
    Keywords: FLUID MECHANICS
    Type: AIAA Journal; 12; Apr. 197
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  • 28
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    Flow properties in expansion tube with helium, argon, air, and CO2 (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Test flow velocities from 5 to 7 km/sec were generated in a 6-in. expansion tube using helium, argon, air, and CO2 test gases. Pitot pressure profiles across the flow at the test section are presented for the four test gases, and measured flow quantities are compared to computer predicted values. Comparison of predicted and measured flow quantities suggests the expansion to be near thermochemical equilibrium for all test gases and implies the existence of a totally reflected shock at the secondary diaphragm. Argon, air, and CO2 flows were observed to attenuate while traversing the acceleration section, whereas no attenuation was observed for helium.
    Keywords: FLUID MECHANICS
    Type: AIAA Journal; 12; Apr. 197
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  • 29
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    Non-equilibrium ionized blast wave (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The structure of a cylindrical blast wave with ionization at non-LTE conditions was calculated using equations previously developed by Wu and Fu (1970). The degree of ionization was predicted by a modified Saha equation. Temperature profiles show that the temperature at non-LTE conditions is lower than at LTE near the shock front. This corresponds to a higher degree of ionization for the non-LTE limit, which indicates that the neutral gas absorption is much more efficient at non-LTE than at the LTE limit. The decaying velocity under non-LTE is approximately 15% less than under LTE.
    Keywords: FLUID MECHANICS
    Type: Physical Society of Japan; vol. 36
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  • 30
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    The stability of supermassive stars in the Parametrized Post-Newtonian framework (1974)
    In:  Other Sources
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    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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  • 31
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    A comparison of homogeneous stellar models based on the Cox-Stewart and Carson opacities (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 194; Dec. 15
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  • 32
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    Fine-scale structure of a cold hydrogen layer (1974)
    In:  Other Sources
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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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  • 33
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    Degeneracy effects of neutrino mass ejection in supernovae (1974)
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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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  • 34
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    Weak interstellar lines in the visible spectrum of zeta Ophiuchi (1974)
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    Publication Date: 2011-08-16
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 193; Oct. 1
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  • 35
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    On the theory of thermal runaway in the hydrogen envelope of a white dwarf (1974)
    In:  Other Sources
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    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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  • 36
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    Estimates of the Venus atmosphere optical characteristics with application to the problem of photographing its clouds and surface (1974)
    In:  Other Sources
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    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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  • 37
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    Applicability of the diffusion approximation (1974)
    In:  Other Sources
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    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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  • 38
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    Remarks on the decay of homogeneous turbulence from a given state (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A previous theory which did not require a usual closure assumption required three or more initial spectra. By allowing a simple physical assumption (a modification of Kovasznay's (1948) hypothesis), the required number of spectra is reduced to two. Agreement with experiment is good.
    Keywords: FLUID MECHANICS
    Type: Physics of Fluids; 17; Mar. 197
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  • 39
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    Progress and problems in erosion prediction (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Methods for predicting erosion resulting from repeated localized impulsive loadings, such a impacts from droplets or in cavitation flow from microjets and bubbles, are examined. The parameters which determine the adequacy of a component to resist the loads put upon it are identified. The development of erosion rate models is discussed. The expected accuracy of the prediction and the sources of error are analyzed.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failure; p 107-114
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  • 40
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    Effects of viscoelasticity on cavitation in drag reducing fluids (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: To study cavitation inception in polymer solutions, a blow-down water tunnel with short running times was used. Tests were made using 1/4 and 1/2 inch diameter models of hemispherical-nose cylinders. To accurately detect the inception of cavitation, a reliable technique was developed using a continuously operating He-Ne gas laser. The laser beam was adjusted to grazing incidence with the model at the minimum pressure point where cavitation inception was to be expected. A sensitive photocell was placed at ninety degrees to detect the beam. As incipient cavitation occurred, the bubbles caused scattering of the laser beam which was picked up by the photocell. Static pressure near the model in the working section of the tunnel was measured using a solid-state pressure pick-up. The signals from the photocell and the pressure pick-up were recorded on an oscillograph. Velocity field visualization was achieved using one microsecond duration light pulses scattered by small polystryrene latex spheres in the flow.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 100-106
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  • 41
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    Effect of cavitation on fluid stability in polymer thickened fluids and lubricants (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The effects of cavitating flow on the polymeric additives used in functional fluids are described. A comparison of thermal and mechanical stability tests for these polymer solutions show distinct differences in the machanism of the polymer degradation. The thermal degradation tests appear to cause an unzippering or depolymerization type of reaction in which there is no particular selectivity based on molecular weight. The mechanical degradation of these fluids appears to be based on molecular weight. Measurements of molecular weight distributions during mechanical degradation show that for a given level of intensity only molecules above a certain minimum size are degraded. The effects of ultrasonic radiation on polymer degradation are reported. Tests were conducted to demonstrate the mechanism of mechanical polymer degradiation in an orifice. A more severe test than the orifice test in which two tapered roller bearings loaded against each other produce the mechanical breakdown is discussed.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 88-99
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  • 42
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    Lubricant pressure rippling in dynamic Hertzian contacts induced by surface roughness (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A numerical analysis of the pressure distribution of a lubricant in contact with a rough surface was conducted. The magnitude of the pressures was determined by their root mean square value for the contact of two dimensional cylinders. The pressure was found to vary in the following manner: (1) the location in the contact, (2) the spectrum or frequency content of the surface roughness, (3) the mean plateau film thickness, and (4) the root mean square value of the surface roughness. Mathematical models are developed to show the relationships of the parameters.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 62-73
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  • 43
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    Examples of oil cavitation erosion in positive displacement pumps (1974)
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    Publication Date: 2011-08-16
    Description: The effects of cavitation flow on piston type, positive displacement, hydraulic pumps are discussed. The operating principles of the pump and the components which are most subject to erosion effects are described. The mechanisms of cavitation phenomena are identified from photographic records. Curves are developed to show the solubility of air in water, oil-water emulsion, and industrial hydraulic oil.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 48-53
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  • 44
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    Some practical examples of cavitation erosion and their prevention (1974)
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    Publication Date: 2011-08-16
    Description: The problem of failures caused by cavitation erosion are discussed. The concepts of intensity of erosion, erosion strength, and the time dependence of erosion rate are analyzed. The relation of these parameters to system variables such as pressure and velocity, and to the properties of materials are investigated. Using several examples of actual cavitation erosion, methods of prevention and their limitations are examined.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 39-47
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  • 45
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    Recent theories of cavitation damage including non-symmetrical bubble collapse effects (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Theories of cavitation damage mechanisms are discussed. Photographic evidence has shown that the actual collapse of bubbles near a symmetry-destroying feature such as a nearby wall results in a toroidal-like collapse, with the final generation of a liquid microjet oriented toward the wall. Numerical analyses indicate that the shock wave intensity emitted during collapse is not likely to be strong enough to be damaging to most materials. It has been determined that actual damage is usually a result of a combination of impact effect of the microjet and the shock wave pressures generated by bubble rebounds.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 31-35
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  • 46
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    The role of mechanical properties in cavitation erosion resistance (1974)
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    Publication Date: 2011-08-16
    Description: Methods for determining the correlations of erosion resistance and mechanical properties of materials are discussed. The most common method of testing cavitation erosion resistance of materials is the vibratory cavitation probe. The instrument and its operation are described. The use of the whirling arm device is considered as a second method. Metallographic investigations of the earliest stages of cavitation erosion damage of metallic materials was conducted. The materials show plastic deformation occurring during the incubation period and increasing until cracks form and metal fragments are lost. The parameters of the work done to cause material fractures are identified. The reactions obtained with specific materials are reported.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 23-30
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  • 47
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    Role of physical properties of liquids in cavitation erosion (1974)
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    Publication Date: 2011-08-16
    Description: The dependence of erosion rates on the ambient temperature of water is discussed. The assumption that the gas inside the bubble is compressed adiabatically during collapse gives better agreement with experiments than the assumption that the gas is isothermally compressed. Acoustic impedance is an important liquid parameter that governs the erosion intensity in vibratory devices. The investigation reveals that the major physical properties of liquids governing the intensity of erosion include density, sound speed, surface tension, vapor pressure, gas content, and nuclei distribution.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 13-22
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  • 48
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    Physics associated with cavitation induced material damage (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The role of cavitation in mechanical failure is discussed. Some of the most common types of material damage associated with the presence of cavitation are surface material removal, delamination and structural vibration. This occurs in external flows such as on propellers, hydrofoils, and high speed non-lifting surfaces. In internal flows, pipe bends, inlets, constructions, pumps and turbines are typical. Nominally nonflowing liquids are also susceptible in, for example, strong acoustic fields and high energy particle detectors. For flowing systems, Bernoulli's equation shows how a local pressure is reduced as the fluid's velocity is increased. At sufficiently high velocities, a tension can actually develop and this has, in fact, been demonstrated experimentally. Once the pressure is reduced below the fluid vapor pressure a vapor cavity can be nucleated. Various aspects of this process are simply shown by considering the flow over a lifting surface.
    Keywords: FLUID MECHANICS
    Type: NBS The Role of Cavitation in Mech. Failures; p 3-12
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  • 49
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    Lyman-alpha imagery of Comet Kohoutek (1974)
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    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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  • 50
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    Interpretation of the anti-tail of Comet Kohoutek as a particle flow phenomenon (1974)
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    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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  • 51
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    A comment on gamma ray lines from He-4 (1974)
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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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  • 52
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    Violation of the Vogt-Russell theorem for homogeneous nondegenerate stars (1974)
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    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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  • 53
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    Neutrino emission from plasmons in strong magnetic fields (1974)
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    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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  • 54
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    X rays predicted from flares of UV Ceti stars (1974)
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    Publication Date: 2011-08-16
    Keywords: ASTROPHYSICS
    Type: Nature; 252; Dec
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  • 55
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    Evidence for a corona of beta Geminorum (1974)
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    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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  • 56
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    Tentative identification of U93.174 as the molecular ion N2H/+/ (1974)
    In:  Other Sources
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    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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  • 57
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    Absolute radiometry and the solar constant (1974)
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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).
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    An experimental test of the homogeneity of the interstellar medium (1974)
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    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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  • 59
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    Origin of fifteen cosmic dust particles intercepted by Pioneer 8 and 9 (1974)
    In:  Other Sources
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    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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  • 60
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    Wall shear in strongly retarded and separated compressible turbulent boundary layers (1974)
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    Publication Date: 2011-08-16
    Keywords: FLUID MECHANICS
    Type: AIAA Journal; 12; Oct. 197
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  • 61
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    Experimental study of the shock-induced unsteady laminar boundary layer on a flat plate (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The behavior of the unsteady laminar boundary layer induced by the incident shock wave passing over a flat plate mounted in a shock tube has been experimentally studied for shock speeds ranging from 2.35 to 7.34 km/sec by measuring unsteady heat transfer rates to the plate using thin-film heat-flux gages. Theoretical heat-transfer rates were predicted from analytical solutions in the literature which describe the unsteady flat plate boundary layer development for equilibrium real-gas flows. Experimental results obtained for both air and nitrogen were found to be in good agreement with the theoretical predictions.
    Keywords: FLUID MECHANICS
    Type: Physics of Fluids; 17; May 1974
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  • 62
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    Conservation equations of gasdynamics in curvilinear coordinate systems (1974)
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    Publication Date: 2011-08-16
    Description: Description of a new method of writing the conservation equations of gasdynamics in curvilinear coordinates which eliminates undifferentiated terms. It is thus possible to readily apply difference schemes derived for Cartesian coordinates which conserve mass, momentum, and energy in the total flow field. The method is derived for orthogonal coordinates, and then extended to cover the most general class of coordinate transformations, using general tensor analysis. Several special features of the equations are discussed.
    Keywords: FLUID MECHANICS
    Type: Journal of Computational Physics; 14; Feb. 197
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  • 63
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    Comments on Crocco's solution and the independence principle for compressible turbulent boundary layers (1974)
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    Publication Date: 2011-08-16
    Description: The purpose of the present note is to show that on a flat plate where both the wall temperature and mean wall pressure are constant, neither of the limitations of parallel flow or of unity for the turbulent Prandtl number are required in order for the Crocco solution to apply to the turbulent boundary-layer flow. It is shown herein that this result is subject to restrictions on the magnitude of pressure fluctuations. The same analysis is generalized to show that the compressible turbulent boundary layer on an isothermal swept flat plate is independent of the spanwise flow if the molecular Prandtl number is unity.
    Keywords: FLUID MECHANICS
    Type: AIAA Journal; 12; Feb. 197
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  • 64
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    Upper atmospheres and diagnostic measurements (1974)
    In:  CASI
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    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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  • 65
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    Estimates of the size of particles in Saturn's rings and their cosmogonic implications (1974)
    In:  CASI
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    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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  • 66
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    The atmosphere of the rings of Saturn (1974)
    In:  CASI
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    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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  • 67
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    Distribution and size of elements of Saturn's rings as inferred from 12-cm radar observations (1974)
    In:  CASI
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    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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  • 68
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    Variations in the infrared brightness temperature of Saturn's rings (1974)
    In:  CASI
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    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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  • 69
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    Saturn's ring particles and space vehicle design (1974)
    In:  CASI
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    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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  • 70
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    Ring particle sizes and composition derived from eclipse cooling curves and reflection spectra (1974)
    In:  CASI
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    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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  • 71
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    Model of Saturn's rings that satisfies the observed phase curve for optical scattering (1974)
    In:  CASI
    Details
    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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  • 72
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    Structure of Saturn's rings: Optical and dynamical considerations (1974)
    In:  CASI
    Details
    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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  • 73
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    Studies of liquid floating zones on SL-IV, the third Skylab mission (1974)
    In:  Other Sources
    Details
    Publication Date: 2019-01-25
    Description: The behavior of liquid floating zones in a zero-gravity environment was studied by Dr. E. Gibson on SL-4. These experiments were designed from the results of previous work on floating zones in a simulated zero-gravity model. Molten floating zones are used on earth for the crystal growth and zone refining of reactive materials. The Skylab studies give some insight into the problems associated with the development of the technique for the future space processing of materials. Preliminary results are presented on the stability of the liquid zone surface under static, rotational and vibrational conditions without gravitational constraints.
    Keywords: FLUID MECHANICS
    Type: NASA. Marshall Space Flight Center Proc. of the 3d Space Processing Symp. on Skylab Results, Vol. 2; p 837-856
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  • 74
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    Fluid motions in a low-G environment (1974)
    In:  Other Sources
    Details
    Publication Date: 2019-01-25
    Description: The importance of natural convection and other fluid motions in low-g space processing is now well recognized. Recent space experiments in the areas of natural convection and material processing, as well as results of theoretical studies, have yielded much needed information on fluid behavior in low-g environments. The state of knowledge of fluid motions in low-g environments is reviewed and the dimensional analysis approach used to assess the relative importances of various driving forces for fluid flow in four of the Skylab material processing experiments outlined. Results of dimensional analyses for the Skylab experiments, subsequently confirmed by actual space data, are presented. Finally, the limits of dimensional analysis in assessment studies are indicated.
    Keywords: FLUID MECHANICS
    Type: NASA. Marshall Space Flight Center Proc. of the 3d Space Processing Symp. on Skylab Results, Vol. 2; p 691-727
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  • 75
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    Rotating stars (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Keywords: ASTROPHYSICS
    Type: JPL Proc. of the Intern. Colloq. on Drops and Bubbles, Vol. 1; p 11-34
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  • 76
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    The fission theory of binary stars (1974)
    In:  CASI
    Details
    Publication Date: 2016-06-07
    Keywords: ASTROPHYSICS
    Type: JPL Proc. of the Intern. Colloq. on Drops and Bubbles, Vol. 1; p 1-10
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  • 77
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    Limits on the neutral hydrogen content of Coma and other clusters of galaxies (1974)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Keywords: ASTROPHYSICS
    Type: Astronomy and Astrophysics; 36; 3, De; Dec. 197
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  • 78
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    Binary stellar winds (1974)
    In:  Other Sources
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    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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  • 79
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    A search for microwave emission from CH in Comet Kohoutek /1973f/ (1974)
    In:  Other Sources
    Details
    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
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  • 80
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    Molecule searches in Comet Kohoutek /1973f/ at microwave frequencies (1974)
    In:  Other Sources
    Details
    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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  • 81
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    On the nature of the anti-tail of Comet Kohoutek /1973f/. I - A working model (1974)
    In:  Other Sources
    Details
    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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  • 82
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    An upper limit on the evolution of carbon monoxide from Comet Kohoutek (1974)
    In:  Other Sources
    Details
    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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  • 83
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    Interstellar carbon I lines in zeta Ophiuchi (1974)
    In:  Other Sources
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    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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  • 84
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    CNO abundances and hydrodynamic models of the nova outburst. III - 0.5 solar mass models with enhanced carbon, oxygen, and nitrogen (1974)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: Consideration of the evolution of thermonuclear runaways in the hydrogen-rich envelopes of 0.5 solar mass carbon-oxygen white dwarfs. The larger radii of these stars, compared with the 1.00 solar mass white dwarfs, results in a lesser degree of degeneracy at the same depth in the star. Four models of luminosity with .00355 solar luminosity, differing only in the initial abundances of C-12, N-14, and O-16, are presented. The degree of enhancement required to produce mass ejection, and thereby a nova-type outburst, is greater than for the 1.00 solar mass model. Nevertheless, the evolution of the 0.5 solar mass model that ejected material is very similar to that of the 1.00 solar mass models, and it also ejects significant amounts of C-13, N-15, and O-17 into the interstellar medium. The 0.5 solar mass outburst is considerably less intense than the 1.00 solar mass outburst (even under optimum conditions), and this lower mass behavior is interpreted as associated with the observed outburst of the slowest novae.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 192; Sept. 15
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  • 85
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    Ultraviolet spectrophotometry of Sirius from Gemini 12 (1974)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The spectral energy distribution of Sirius between 2500 and 3700 A at a resolution of 7 A is obtained from plates taken on Gemini 12. The agreement with other observations and the most recent line-blanketed model atmospheres is good. The equivalent width of the Mg II doublet near 2800 A is 6.0 A, if the continuum level is represented by regions near 2650 and 2910 A. This is consistent with expectations for a hot Am star and implies line blocking of up to 15% in this wavelength region.
    Keywords: ASTROPHYSICS
    Type: Astrophysical Journal; 192; Sept. 15
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  • 86
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    Experiments on confined turbulent jets in cross flow (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Results are reported of experiments on the effects of an opposite wall on the characteristics of turbulent jets injected into a cross flow, for unheated and heated jets. Longitudinal and transverse distributions of velocity and temperature are presented for single and multiple circular jets, and trajectories are presented for two-dimensional jets. The opposite wall has relatively little effect on a single jet unless the ratio of jet to cross flow momentum flux is large enough for the jet to impinge on the opposite wall. For a row of jets aligned perpendicularly to the cross flow, the opposite wall exerts progressively larger influence as the spacing between jets decreases. Much of the effect of jet and wall proximity can be understood by considering the interaction of the vortex flow which is the major feature of the structure of a single jet in a cross flow. Smoke photographs are shown to elucidate some of the interaction patterns.
    Keywords: FLUID MECHANICS
    Type: NASA-CR-2392
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  • 87
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    Decay of far flow field in trailing vortices (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A finite difference machine code is used in the wake vortex problems in the quasi-cylindrical boundary layer approximation. A turbulent energy model containing new features is developed that accounts for the major effects disclosed by more advanced models in which the parameters are not yet established. Several puzzles that arose in previous theoretical investigations of wake vortices are resolved.
    Keywords: FLUID MECHANICS
    Type: NASA-TN-D-7568 , A-5181
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  • 88
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    Effect of throttling on interface behavior and liquid residuals in weightlessness (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An experimental investigation was conducted to study liquid-vapor interface behavior and subsequent vapor ingestion in a flat-bottomed cylindrical tank following a single-step throttling in outflow rate in a weightless environment. A throttling process in which the final Weber number was one-tenth of the initial Weber number tended to excite large-amplitude symmetric slosh, with the amplitude generally increasing as initial Weber number increased. As expected, liquid residuals were lower than those obtained without throttling and, for moderate values of initial Weber number, could be adequately predicted by assuming that all draining took place at the final Weber number. At large values of Weber number, residuals tended to be lower than this predicted value.
    Keywords: FLUID MECHANICS
    Type: NASA-TM-X-3034 , E-7833
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  • 89
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    Comparison of measured and calculated velocity profiles of a laminar incompressible free jet at low Reynolds numbers (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: A comparison of the measured and calculated velocity profiles of a laminar, incompressible, low Reynolds number jet is presented. The experimental jet was produced by a nozzle which consists of a porous metal plate covering the end of a pipe. This nozzle produces a uniform exit velocity profile at Reynolds numbers well below those at which conventional contoured nozzles are completely filled by the boundary layer. A jet mixing analysis based on the boundary-layer equations accurately predicted the velocity field for each test condition. The Reynolds number based on nozzle diameter ranged from 50 to 1000 with jet exit velocity either 30 or 61 m/s (100 or 200 ft/sec).
    Keywords: FLUID MECHANICS
    Type: NASA-TN-D-7510 , L-9277
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  • 90
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    An experimental investigation of wall boundary layer transition Reynolds numbers in an expansion tube (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Experimental measurements of boundary-layer transition in an expansion-tube test-gas flow are presented along with radial distributions of pitot pressure. An integral method for calculating constant Reynolds number lines for an expansion-tube flow is introduced. Comparison of experimental data and constant Reynolds number calculations has shown that for given conditions, wall boundary-layer transition occurs at a constant Reynolds number in an expansion-tube flow. Operating conditions in the expansion tube were chosen so that the effects of test-gas nonequilibrium on boundary-layer transition could be studied.
    Keywords: FLUID MECHANICS
    Type: NASA-TN-D-7541 , L-9337
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  • 91
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    The application of Riegels' rule and time-like damping to transonic flow calculations (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Finite difference relaxation solutions of the nonlinear small perturbation equations have proven reliable and successful in determining the transonic flowfields about thin airfoils. However, application of the small perturbation approach to thick airfoils usually results in an accuracy less than desirable. The incorporation of Riegels' Rule and time-like damping into the small perturbation approach and their application to thick and thin airfoils in transonic flow are discussed. Studies for thick and thin airfoils are presented. It is concluded that Riegels' Rule and damping should both be included in small perturbation transonic flow calculations.
    Keywords: FLUID MECHANICS
    Type: NASA-CR-138181 , TAMRF-3033-7401 , AIAA Southwestern Student Paper Competition; Arlington, TX; United States
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  • 92
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    A weak interaction study of the viscous flow about oscillating airfoils (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: An incompressible inviscid and a viscous flow calculation procedure is developed by assuming the viscous correction to the inviscid flow pressure distribution is small (weak interaction) to predict the flow about airfoils oscillating in pitch and heave. The calculations made in the investigation predict the detailed viscous flow regions including transition and separation phenomena and provide a detailed analysis of leading edge separation, transition, and reattachment. Results from the calculation show the leading edge viscous flow field to be quasi-steady although the imposed inviscid pressure distribution shows significant unsteady effects. Although unable to predict the flow field about a stalled airfoil, the indications are that the present procedure can indicate the onset of catastrophic flow separation.
    Keywords: FLUID MECHANICS
    Type: NASA-CR-132425
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  • 93
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    Topics in structural dynamics: Nonlinear unsteady transonic flows and Monte Carlo methods in acoustics (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The results are reported of two unrelated studies. The first was an investigation of the formulation of the equations for non-uniform unsteady flows, by perturbation of an irrotational flow to obtain the linear Green's equation. The resulting integral equation was found to contain a kernel which could be expressed as the solution of the adjoint flow equation, a linear equation for small perturbations, but with non-constant coefficients determined by the steady flow conditions. It is believed that the non-uniform flow effects may prove important in transonic flutter, and that in such cases, the use of doublet type solutions of the wave equation would then prove to be erroneous. The second task covered an initial investigation into the use of the Monte Carlo method for solution of acoustical field problems. Computed results are given for a rectangular room problem, and for a problem involving a circular duct with a source located at the closed end.
    Keywords: FLUID MECHANICS
    Type: NASA-CR-138110 , ESS-4022-113-74
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  • 94
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    Drag and distribution measurements of single-element fuel injectors for supersonic combustors (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The drag caused by several vortex generating fuel injectors for scramjet combustors was measured in a Mach 2 to 3.5 airstream. Injector drag was found to be strongly dependent on injector thickness ratio. The distribution of helium injected into the stream was measured both in the near field and the far field of the injectors for a variety of pressure ratios. The far field results differed appreciably from measurements in the near field. Injection pressure ratio was found to profoundly influence the penetration. One of the aerowing configurations tested yielded low drag consistent with desirable penetration and spreading characteristics.
    Keywords: FLUID MECHANICS
    Type: NASA-TM-X-3015 , E-7662
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  • 95
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    Numerical calculations of two dimensional, unsteady transonic flows with circulation (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: The feasibility of obtaining two-dimensional, unsteady transonic aerodynamic data by numerically integrating the Euler equations is investigated. An explicit, third-order-accurate, noncentered, finite-difference scheme is used to compute unsteady flows about airfoils. Solutions for lifting and nonlifting airfoils are presented and compared with subsonic linear theory. The applicability and efficiency of the numerical indicial function method are outlined. Numerically computed subsonic and transonic oscillatory aerodynamic coefficients are presented and compared with those obtained from subsonic linear theory and transonic wind-tunnel data.
    Keywords: FLUID MECHANICS
    Type: NASA-TN-D-7605 , A-5265
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  • 96
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    Wind tunnel investigation of aerodynamic characteristics of a scale model of a D5 bulldozer and an M109 self-propelled 155 mm Howitzer (1974)
    In:  CASI
    Details
    Publication Date: 2019-06-27
    Description: Wind tunnel tests were conducted on a scale model of a D5 bulldozer and an M109 self-propelled 155 MM howitzer to determine the aerodynamic characteristics of these typical externally-suspended heavy lift helicopter cargo configurations. Tests were made over a large range of pitch and yaw attitudes at a nominal Reynolds number per unit length of 1.5 x 10 to the 6th power.
    Keywords: FLUID MECHANICS
    Type: NASA-TM-X-62330
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  • 97
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    Ionisation structure and transfer of radiation in dusty nebulae (1974)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: Analytic expressions describing the infrared radiation and hydrogen to helium line intensity ratios from a dusty nebula are presented. Implications of these results are discussed briefly.
    Keywords: ASTROPHYSICS
    Type: ESRO H2 Regions and the Galactic Centre; p 173-178
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  • 98
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    Dust in H2 regions (1974)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: The effects of dust inside H2 regions were studied by means of theoretical models of dusty nebulae. Infrared observations were analyzed and clear evidence was found that the emitting dust is mostly mixed with the ionized gas. Some information about the amount, distribution, and properties of dust grains was also derived.
    Keywords: ASTROPHYSICS
    Type: ESRO H2 Regions and the Galactic Centre; p 163-171
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  • 99
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    Evolutionary characteristics of a bimodal grain model (1974)
    In:  Other Sources
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    Publication Date: 2019-06-27
    Description: A bimodal model of interstellar grains consisting of silicate cores of size approximately 0.06 micron with modified ice mantles of approximately 0.1 micron and very small particles of silicate and/or graphite of size approximately 0.005 micron is followed through various stages of evolution. Starting with a distribution of core-mantle cylinders producing average wavelength dependence of polarization and extinction, changes in physical and optical characteristics of the model are studied going first into regions of dense cloud condensation and coming out at the other end of star formation into young H2 regions. Physical justification is presented to show that not only in dense clouds must the core mantle grains be larger than normal, but also in young H2 regions.
    Keywords: ASTROPHYSICS
    Type: ESRO H2 Regions and the Galactic Centre; p 153-162
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  • 100
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    Expected far infrared polarization of H2 regions and the nuclei of galaxies (1974)
    In:  Other Sources
    Details
    Publication Date: 2019-06-27
    Description: The expected polarization of far infrared sources is discussed, and it is shown that the observed degree of polarization generally depends on two factors: (1) the availability of a mechanism that can produce polarization, and (2) the gain in polarization which absorption or stimulated emission can produce within a source. It is pointed out that stimulated emission could produce sizeable gain changes in compact dust clouds such as those associated with H2 regions and possibly also in dense regions exhibiting OH and H2O masers. Whether such a gain can actually become positive (maser-like behavior) is not clear, but this would in any case depend on the chemical structure of the grain material and the spectral range of interest.
    Keywords: ASTROPHYSICS
    Type: ESRO H2 Regions and the Galactic Centre; p 179-184
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