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  • SPACE SCIENCES  (6,789)
  • STRUCTURAL MECHANICS  (1,510)
  • AERODYNAMICS
  • 1970-1974  (9,555)
Collection
Keywords
Years
Year
  • 1
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    A method for determining optimum re-entry trajectories (1974)
    In:  CASI
    Details
    Publication Date: 2006-04-02
    Description: The Pontryagin Maximum Principle is used to formulate the problem of finding optimum atmospheric vehicular reentry trajectories. The optimization problem is that of minimizing an integral which is a function of the state and control variables. The vehicle's motion is assumed to be influenced by a gravitational force and an aerodynamic force. The problem is formulated and the necessary equations are developed simultaneously for three sets of Euler angles. Computational procedures are suggested so that numerical trajectories may be generated.
    Keywords: SPACE SCIENCES
    Type: Multivariant Function Model Generation; 93 p
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  • 2
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    Vehicle control for fuel optimization (1974)
    In:  CASI
    Details
    Publication Date: 2006-04-02
    Description: The problem of predicting the minimum fuel trajectory for a six degree of freedom vehicle which has a motion characterized by the first order differential equations of translational and rotational dynamics is considered. The thrust direction and center of gravity of the vehicle are assumed to be fixed with respect to the vehicle. Thrust magnitude and the control moment are used as control variables and appear linearly in the equation of motion. Pontryagin's Maximum Principle is used to solve the variational problem. With this formulation, the extremal controls are bang-bang with the exception of the singular case.
    Keywords: SPACE SCIENCES
    Type: Multivariant Function Model Generation; 18 p
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  • 3
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    Space flights and questions of law (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Juridical aspects of space flights and international law are elaborated. Considered are manned orbital space stations, as well as lunar or planetary bases and the international exploration of extraterrestrial resources.
    Keywords: SPACE SCIENCES
    Type: Inhabited Space, Pt. 2 (NASA-TT-F-820); p 170-175
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  • 4
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    Are interstellar flights possible? (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: It is shown that ionic relativistic rockets are most suitable for carrying out interstellar flights in comparison with photonic rockets or nuclear interstellar aircraft. Slow interstellar flights are much more probable than fast flights.
    Keywords: SPACE SCIENCES
    Type: Inhabited Space, Pt. 2 (NASA-TT-F-820); p 154-160
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  • 5
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    Searching for extra-terrestrial civilizations (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: The probability of radio interchange with extraterrestrial civilizations is discussed. Difficulties constitute absorption, scattering, and dispersion of signals by the rarified interstellar medium as well as the deciphering of received signals and convergence of semantic concept. A cybernetic approach considers searching for signals that develop from astroengineering activities of extraterrestrial civilizations.
    Keywords: SPACE SCIENCES
    Type: Inhabited Space, Pt. 2 (NASA-TT-F-820); p 83-110
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  • 6
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    Multiplicity of inhabited worlds and the problem of setting up contacts among them (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: The numerous planetary systems in our galaxy appear to a high degree of probability to contain some planets with a biosphere similar to earth' environment. The possibility of communicating with those extraterrestrial alien planetary civilizations centers on the high level of technological development that is required to overcome the problem of distance. It is conceivable that advanced civilizations can produce energy at a level of 10 to the 43rd power erg/year and that an artificial biosphere can be developed within the limits of 10 to the 22nd power to 10 to the 23rd power cm.
    Keywords: SPACE SCIENCES
    Type: Inhabited Space, Pt. 2 (NASA-TT-F-820); p 67-78
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  • 7
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    Problem of searching for extra-terrestrial civilizations (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Possible criteria characterizing extraterrestrial civilizations and their detection are: (1) deduction of their existence by evaluating astronomical prerequisites for the development of life in remote planetary systems; (2) detection and communication with extraterrestrial civilizations; and (3) the problem of language and content of information in transmitted signals.
    Keywords: SPACE SCIENCES
    Type: Inhabited Space, Pt. 2 (NASA-TT-F-820); p 62-66
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  • 8
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    Research on development of equations for performance trajectory computation (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: A computer program for computing the performance trajectory of spacecraft was developed. An analytical study of a minimum fuel flight for high speed aircraft was conducted. The computer program to compute a minimum time reentry into the atmosphere for an Apollo-type capsule is presented. A technical summary of the minimum fuel problem is provided.
    Keywords: SPACE SCIENCES
    Type: Multivariant Function Model Generation; 34 p
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  • 9
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    Noise and vibration level reduction by covering metal structures with layers of damping materials (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: One of the most important methods of reducing the noise and vibration level is the damping of the secondary sources, such as metal plates, often used in vehicle structures, by means of covering materials with high internal viscosity. Damping layers are chosen at an optimum thickness corresponding to the frequency and temperature range in which a certain structure works. The structure's response corresponding to various real situations is analyzed by means of a measuring chain including electroacoustical or electromechanical transducers. The experimental results provide the dependence of the loss factor and damping transmission coefficient as a function of the damping layer thickness or of the frequency for various viscoelastic covering materials.
    Keywords: STRUCTURAL MECHANICS
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 246-253
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  • 10
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    Vibration and recoil control of pneumatic hammers (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Vibration sources are described for pneumatic hammers used in the mining industry (pick hammers), in boiler shops (riveting hammers), etc., bringing to light the fact that the principal vibration source is the variation in air pressure inside the cylinder. The present state of the art of vibration control of pneumatic hammers as it is practiced abroad, and the solutions adopted for this purpose, are discussed. A new type of pneumatic hammer with a low noise and vibration level is presented.
    Keywords: STRUCTURAL MECHANICS
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 79-84
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  • 11
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    Vibration control in forge hammers (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Special measures are discussed for calculating, designing and executing a forge hammer foundation, so that the vibrations that occur during its working will not be transmitted to neighboring machinery, workrooms and offices. These vibrations are harmful to the workers near the forge hammer.
    Keywords: STRUCTURAL MECHANICS
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 73-78
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  • 12
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    Experimental determination of the vibration level in 5,100 kW electric locomotive assemblies (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Because of the high vibration level occurring during the running of electric locomotives, mechanical defects occur in the control mechanisms of auxiliary services. This fact has given rise to the necessity of determining the values of these vibrations in electric locomotives during their running. Measurements were conducted on the Craiova-Drobeta-Turnu Severin line, and measures to reduce the vibration level in electric locomotives were instituted.
    Keywords: STRUCTURAL MECHANICS
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 50-54
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  • 13
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    Random vibrations of linear viscoelastic beams with lumped masses (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: A method is presented of determining the mean square transversal deflection of an isotropic and homogeneous linear viscoelastic beam having a certain number of lengthwise distributed lumped masses. It is assumed that the beam is acted upon by a stationary random process uniformly distributed along the beam. The method is useful in vibration level control by means of additional lumped masses.
    Keywords: STRUCTURAL MECHANICS
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 36-42
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  • 14
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    Random vibrations of quadratic damping systems (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: An oscillating system with quadratic damping subjected to white noise excitation is replaced by a nonlinear, statistically equivalent system for which the associated Fokker-Planck equation can be exactly solved. The mean square responses are calculated and the optimum damping coefficient is determined with respect to the minimum mean square acceleration criteria. An application of these results to the optimization of automobile suspension damping is given.
    Keywords: STRUCTURAL MECHANICS
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 29-35
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  • 15
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    The response of many-storied structures under seismic actions (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: A seismic action which is characterized by the acceleration function of the seismic motion is analyzed. The equations of motion in the direction of the seismic action are determined for a completely rigid ground and for a ground with linear deformability characteristics (rotation deformability). The equation for the rotation motion is derived by considering elastic and viscoelastic properties of the foundation ground. The differential equations are written by treating the mechanical model of a many-storied structure as a fixed vertical beam with a uniformly distributed mass as well as with concentrated masses on each floor.
    Keywords: STRUCTURAL MECHANICS
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 43-49
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  • 16
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    Insulation of nonlinear and random vibrations in the mining industry (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: The insulation of nonlinear and random vibrations is considered for some ore preparing and sorting implements: rotary crushers, resonance screens, hammer mills, etc. The appearance of subharmonic vibrations is analyzed, and the conditions for their appearance are determined. A method is given for calculating the insulation of these vibrations by means of elastic elements made of rubber. The insulation of the random vibrations produced by Symons crushers is calculated by determining the transmissability and deformation of the insulation system for a narrow band random response.
    Keywords: STRUCTURAL MECHANICS
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 22-28
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  • 17
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    A mathematical model for storied buildings subjected to automatic loom stresses (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Expressions are derived for the displacements of a many storied building subjected to the action of classical weaving looms located at different levels of the building. The building is regarded as a vertical fixed beam with a uniformly distributed mass as well as concentrated masses at each level. The calculation relations are obtained on the assumption of harmonic variation of the forces acting at each level as well as the assumption of narrow band stationary random excitatory forces.
    Keywords: STRUCTURAL MECHANICS
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 15-21
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  • 18
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    Study of vibrations produced by a vibrating beam used for vibrating concretes (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: For compacting concretes in building, vibrating beams are used. The vibrations are generated by inertial vibrators, and the beam is normally displaced by the operator by means of a handle that is elastically fastened to the beam by means of rubber pads. Considered are vibrations transmitted to the operator, taking into account the beam's shock vibration motions. The steady state motion of a dynamic beam pattern is studied, and results of experimental tests with existing equipment are presented.
    Keywords: STRUCTURAL MECHANICS
    Type: The 4th Natl. Conf. on Acoustics, Vol. 1A (NASA-TT-F-15375); p 9-14
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  • 19
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    Diurnal and seasonal trends in the incidence of Sudden Commencements (SC) and Sudden Impulses SI (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Based on world data for the period 1 January 1955 to 31 December 1968, reports of 894 SC cases and 2152 SI cases were collected. A study was made of the diurnal and seasonal trends in the incidence of their appearances. It is shown that the diurnal trend is pronounced for all events with a maximum at (06-8)h universal time. The diurnal trend for SC in the resultant period is more pronounced. The seasonal trend in incidence of appearances of SC and SI is absent. Thus, geomagnetic disturbances of both SC and SI are monitored by world time. These results lead to the conclusion that the presence or absence of SC and SI during geomagnetic storms is determined not only by the nature of the corpuscular flux, the presence of shock waves and tangential discontinuities, but also by purely terrestrial conditions.
    Keywords: SPACE SCIENCES
    Type: in its Space Res. in the Ukraine, No. 3 (NASA-TT-F-15537); p 54-68
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  • 20
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    Study of the moon and planets at the Khar'kov State University Astronomical Observatory (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: The results of observations of the moon and planets are presented and include: (1) data on the discovery of high porosity values and the broken terrain of the lunar surface, and (2) data on the coloration of lunar rocks. A comparative description is given of data obtained by astronomical and by satellite observations.
    Keywords: SPACE SCIENCES
    Type: Space Res. in the Ukraine, No. 3 (NASA-TT-F-15537); p 29-43
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  • 21
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    Long-term integrated radiophysical studies of the ionosphere, near space, and the propagation of radio waves from space objects (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: The radiophysical studies reported consist of direct measurements of certain effects induced in the propagation of radio waves from space objects. From measured effects and from data on the motion and position of space objects, physical parameters of the medium and bodies are determined.
    Keywords: SPACE SCIENCES
    Type: Space Res. in the Ukraine, No. 3 (NASA-TT-F-15537); p 1-28
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  • 22
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    Development of an analog of lunar soil (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Volcanic tuff from the Artik deposit in Armenia is especially suited for experiments in simulating lunar soil, with the aid of compaction by vibration.
    Keywords: SPACE SCIENCES
    Type: Current Concepts Regarding the Moon (NASA-TT-F-766); p 186-191
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  • 23
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    Laboratory simulation of processes of evaporation, condensation, and sputtering taking place on the surface of the moon (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Study of evaporation, condensation and sputtering on the moon can provide information on the same processes on other planets, and reveal details of the formation of the lunar regolith. Simulation methods include vacuum evaporation, laser evaporation, and bubbling gas through melts.
    Keywords: SPACE SCIENCES
    Type: Current Concepts Regarding the Moon (NASA-TT-F-766); p 155-185
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  • 24
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    Geological mapping of the moon (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: Compilation and labelling of geological and morphological charts on a scale of 1:1,000,000 are discussed with emphasis on the regions of Maria Tranquilitatis, Crisium, Fecunditatis, Humorum and Nukium as well as certain prominent craters.
    Keywords: SPACE SCIENCES
    Type: Current Concepts Regarding the Moon (NASA-TT-F-766); p 97-138
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  • 25
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    Results of investigation of the surface layer of the moon on the basis of its intrinsic radiation (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: The intrinsic thermal radiation of the moon is an indicator of the temperature regime of the lunar surface, its physical conditions and structure, as indicated by data from Luna 9 and 13, as well as Surveyor 1 to 7.
    Keywords: SPACE SCIENCES
    Type: Current Concepts Regarding the Moon (NASA-TT-F-766); p 63-96
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  • 26
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    The problem of the structure of the surface of the lunar maria (1974)
    In:  CASI
    Details
    Publication Date: 2006-01-11
    Description: The results are described of geological and morphological interpretation of large-scale photographs of the surface of lunar maria. A morphological classification is proposed for small craters. It is shown that the classification of a crater in a given morphological category, reflecting the degree of its morphological maturity, is determined by the age of the given crater. A check on the nature of distribution of small craters, as done on the basis of the nearest neighbor method, show that the distribution is governed by a near-random law. It is found that variations of the probability density function for the craters conform to a normal distribution law. An empirical relation is found for the coefficient of variation as a function of crater diameter and the dimensions of the area on which the counts are made. The rockfalls near craters of various morphological classes are described.
    Keywords: SPACE SCIENCES
    Type: Current Concepts Regarding the Moon (NASA-TT-F-766); p 25-62
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  • 27
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    Stresses in dome-shaped shells of revolution with discontinuities at the apex (1974)
    In:  CASI
    Details
    Publication Date: 2006-04-02
    Description: Asymptotic solutions of Novozhilov's equations of shells of revolution are derived for axisymmetric and first harmonic loadings. The solutions obtained are valid throughout the shallow and nonshallow regions. Stresses in dome shaped shells of revolution with a discontinuity in the form of a circular hole, a circular rigid insert, or a nozzle at the apex have been investigated. Numerical results are obtained for spheres, ellipsoids, and paraboloids, containing a discontinuity under a internal pressure and moment. Curves depicting stress distributions are given. The influence of three types of discontinuity on the stresses of the shells is also given.
    Keywords: STRUCTURAL MECHANICS
    Type: Multivariant Function Model Generation; 118 p
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  • 28
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    Current structural vibration problems associated with noise (1974)
    In:  CASI
    Details
    Publication Date: 2011-10-14
    Description: As the performance of aerospace vehicles has increased, the noise generated by the propulsion system and by the passage of the vehicle through the air has also increased. Further increases in performance are now underway for space vehicles such as the space shuttle vehicle and for short distance takeoff and landing (STOL) aircraft, and are being planned for supersonic aircraft. The flight profiles and design features of these high-performance vehicles are reviewed and an estimate made of selected noise-induced structural vibration problems. Considerations for the prevention of acoustic fatigue, noise transmission, and electronic instrument malfunction are discussed.
    Keywords: STRUCTURAL MECHANICS
    Type: AGARD Noise Mech.; 16 p
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  • 29
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    Lifting-surface theory for a semi-infinite wing in oblique gust (1974)
    In:  Other Sources
    Details
    Publication Date: 2011-08-16
    Description: An unsteady lifting-surface theory is developed for the calculation of the airload on a semi-infinite-span thin wing in a compressible flow due to interaction with an oblique gust. By using the solutions obtained for a two-dimensional wing, the problem is formulated so that the unknown is taken to be the difference between the airload on the semi-infinite wing and that on a two-dimensional wing under the same gust conditions. Since this airload difference is nonzero only near the wing tip, the control points need be distributed in the tip region only; this significantly simplifies the numerical procedure. Results are presented for a wing with rectangular tip. The implication for noise and unsteady loads due to blade-vortex interaction for helicopter rotors is discussed.
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; Dec. 197
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  • 30
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    Inclusion of transverse shear deformation in finite element displacement formulations (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A stiffness matrix is derived for a beam element with transverse shear deformation. It is shown that straightforward energy minimization yields the correct stiffness matrix in displacement formulations when transverse shear effects are considered. Since the TIM4 beam element does not represent the geometric boundary conditions for a cantilever beam the rotation of the normal must be retained as a grid point degree of freedom.
    Keywords: STRUCTURAL MECHANICS
    Type: AIAA Journal; 12; Nov. 197
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  • 31
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    Planetary entry aerothermodynamics. II - Computational analyses and flight experience (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Limitations concerning the possibility to simulate all the significant flow and thermal phenomena occurring during the entry of a space vehicle into a planetary atmosphere make it necessary to rely on computational analyses to obtain the required data for the design of the spacecraft needed for the NASA missions planned for the next two decades. 'Benchmark' computer programs concerned with complete, detailed, and accurate computational solutions of entry problems are considered along with programs representing engineering approximations for cases in which the accuracy provided by the benchmark programs is not needed. The information obtainable by computational analysis has to be supplemented by actual flight experience in order to meet the goals of the NASA entry-technology program. The individual space missions planned for the coming years are examined together with the possibilities for obtaining the data needed to satisfy the entry requirements in each case.
    Keywords: AERODYNAMICS
    Type: Astronautics and Aeronautics; 12; Dec. 197
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  • 32
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    Infrared astronomy and the Shuttle (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The infrared spectral range extends approximately from 1 micron to 1000 microns. Observations in infrared astronomy are made with the aid of ground-based telescopes and telescopes flown in aircraft, balloons, or rockets. Advantages and drawbacks of infrared studies conducted by different approaches are discussed. Infrared astronomers are looking forward to observations made from orbiting spacecraft. Present plans call for placing a large telescope aboard the Space Shuttle Orbiter for short missions lasting from seven days to three weeks several times a year. However, the occurrence of a pollution of the spacecraft environment by dust particles and gases coming from the spacecraft might present a problem for the observations. Possible approaches for solving this problem are discussed.
    Keywords: SPACE SCIENCES
    Type: Astronautics and Aeronautics; 12; Oct. 197
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  • 33
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    Galactic X-ray sources (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Data on galactic X-ray sources from rocket and balloon experiments and the UHURU satellite are reported. The outline emphasizes general discrete source models and begins with some a priori considerations about X-ray emission mechanisms and their applicability, after which contemporary data are interpreted according to these models. Topics covered include the production of X-rays by various mechanisms, source regimes, observational parameters, stellar distributions, individual stars, flare stars, supernovae and pulsars, the Crab nebula, old and young remnants, binary systems, and others.
    Keywords: SPACE SCIENCES
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  • 34
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    Radio astronomy (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The origins, generation, detection, and interpretation of radio signals are discussed for signals with an assumed random polarization. After defining the basic parameters, the discussion moves to such topics as synchrotron radiation, plasma effects, changes in the electron energy spectrum in the radiating regions, energy loss to ionization, bremsstrahlung, radio astronomical observations of high-energy particles, emission by energetic particles, observation of supernova remnants and pulsars, galactic background continuum radiation, and others.
    Keywords: SPACE SCIENCES
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  • 35
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    Analysis of acoustic radiation in a jet flow environment (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The analysis of sound fields from arbitrary source distributions in terms of Legendre and spherical Hankel functions is well known. The purpose of this paper is to extend this classical method of analysis to environments such as jet flows where flow and flow gradients are inherently present. The wave-equation governing the radiation of sound in such an environment is derived. The steady state flow and flow gradients in the axial and transverse directions appear as coefficients in the terms of the wave-equation. A semi-numerical method is used to solve the wave-equation in terms of modified spherical harmonics yielding the phase velocities and the directivities of an infinite set of modes. The directivity of each mode is obtained in terms of modified Legendre functions by numerical integration. Some results of these directivity and phase-velocity calculations are presented for a limited number of frequency and flow parameters. Both convective and shear refraction are shown to be important.
    Keywords: AERODYNAMICS
    Type: Journal of Sound and Vibration; 36; Sept. 8
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  • 36
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    Jupiter emission observed near 1 MHz (1974)
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    Publication Date: 2011-08-16
    Description: Emission from Jupiter has been observed by the IMP-6 spacecraft at 19 frequencies between 600 and 9900 kHz covering the period from April 1971 to October 1972. The Jovian bursts were identified in the IMP-6 data through the phase of the observed modulated signal detected from the spinning dipole antenna. Initial data reduction has isolated 177 events over a span of 500 days. These events persisted over a period between 1 and 60 min. Of these events at least 48 occurred during times in which Jupiter emission was being observed at either 16.7 or 22.2 MHz by ground-based instruments of the Goddard Space Flight Center Jupiter monitoring system. Large bursts were detectable from 9900 kHz down to 600 kHz, while smaller bursts ranged down to 1030 kHz.-
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 192; Sept. 1
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    The interplanetary and near-Jupiter meteoroid environments (1974)
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    Publication Date: 2011-08-16
    Description: The meteoroid penetration detectors on the Pioneer 10 spacecraft recorded 67 meteoroid penetrations through the 25-micron stainless steel test material while the spacecraft was between 1.0 and 5.1 AU. Ten of these penetrations occurred during the encounter with Jupiter. The cumulative spatial density of meteoroids with masses greater than 2 nanograms has been calculated from these data for interplanetary space and for the near-Jupiter space. The spatial density is found to be essentially constant in interplanetary space between 1 and 5 AU, approximately 1 meteoroid per cubic km, and 1-2 orders of magnitude greater near Jupiter. There was no increase in the spatial density of meteoroids in the asteroid belt and hence no evidence that there is a significant asteroidal component of 2-nanogram meteoroids. It is uncertain whether the meteoroids detected near Jupiter were in orbit about Jupiter or were gravitationally focused toward the planet from solar orbits.
    Keywords: SPACE SCIENCES
    Type: Journal of Geophysical Research; 79; Sept. 1
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    Mapping of the moon: Past and present (1974)
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    Publication Date: 2011-08-16
    Description: The present work provides an outline of the history of the efforts to map the topography of the surface of the moon, from the days of pre-telescopic astronomy to the present. The first part of the book covers the time span from 1600 to 1960 and reproduces numerous examples of this early, earth-based selenographic work. The manned lunar missions in the 1960's revolutionized the science of lunar mapping with their high-resolution, close-range photography of the moon. In 1959, a comprehensive lunar mapping program was initiated by two DOD mapping agencies - the U.S. Air Force Aeronautical Chart and Information Center (ACIC) and the U.S. Army Map Service (AMS). In the course of this program, the cause of lunar mapping enlisted for the first time the services of professional cartographers; the outcome of their efforts speedily relegated all previous work into absolescence. The methods and results of this work are described, and the underlying principles of physical selenodesy are set forth, including the definition of lunar coordinates and the methods for a determination of three-dimensional coordinates of lunar features. A section is included on lunar mapping in the U.S.S.R.
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    Influence of rotation on the maximum mass of pulsationally stable stars (1974)
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    Publication Date: 2011-08-16
    Description: The critical mass for stability against radial pulsations in rotating, homogeneous main-sequence stars is found to be greater than in the case of no rotation. Analytic and detailed numerical models show that the critical mass rises steeply with increasing concentration of angular momentum to the center of the star. For uniform rotation near breakup velocity at the star's equator the critical mass is about 850 solar masses if an electron-scattering opacity is used, or about 5000 solar masses if the opacities of Cox and Stewart are used. For nonuniform rotation with a constant ratio of centrifugal force to gravity in the star, the critical mass becomes 'infinite' long before breakup velocity is attained. The relevance of the present results to several observational problems is noted.
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 192; Aug. 15
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  • 40
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    Unified approach to aerodynamic sound generation in the presence of solid boundaries (1974)
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    Publication Date: 2011-08-16
    Description: A general equation governing aerodynamic sound generation in the presence of solid boundaries is derived. It is shown that all the theories in the literature appear as special cases of this general equation. Derived special equations for propeller and fan noise are likewise shown to be more general than the conventional equations in that they make allowance for variation in retarded time over the blade surfaces.
    Keywords: AERODYNAMICS
    Type: Acoustical Society of America; vol. 56
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  • 41
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    The peculiar A star HD 200311 - A photographic region line-identification study (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: SPACE SCIENCES
    Type: vol. 28; June 197
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  • 42
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    Cosmogony of the asteroidal belt (1974)
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    Publication Date: 2011-08-16
    Description: In the plot of asteroids considered the mass density is substituted for the number density. This approach provides a better definition of the limits of the main belt, and demonstrates more clearly that the asteroids, like the Saturnian rings, have condensed from partially corotating plasma. A diagram shows that the whole main belt is located below 2/3 of Jupiter's orbit. This means that the main belt asteroids may have been derived from condensation which took place inside Jupiter's orbit.
    Keywords: SPACE SCIENCES
    Type: Nature; 250; Aug. 23
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  • 43
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    Exploring Jupiter and its satellites with an orbiter (1974)
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    Publication Date: 2011-08-16
    Description: Review of the initial studies that define a challenging Mariner Jupiter Orbiter mission. Elegant and precise astrodynamics are shown to make possible a bravura examination of the entire Jovian system with two Mariner-class spacecraft to be launched in 1981. This mission is expected to advance considerably our understanding of the origin and evolution of the solar system.
    Keywords: SPACE SCIENCES
    Type: Astronautics and Aeronautics; 12; Sept
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  • 44
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    Lunar electrical conductivity (1974)
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    Publication Date: 2011-08-16
    Description: It is pointed out that the lunar magnetometer experiment has made important contributions to studies of the lunar interior. Numerical inversions of the lunar electromagnetic response have been carried out, taking into account a void region behind the moon. The amplitude of the transfer function of an eight-layer model is considered along with a model of the temperature distribution inside the moon and the amplitude of the transfer function of a semiconductor lunar model.
    Keywords: SPACE SCIENCES
    Type: Nature; 250; Aug. 16
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  • 45
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    Radio detection of Jupiter-like extra-solar planets (1974)
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    Publication Date: 2011-08-16
    Keywords: SPACE SCIENCES
    Type: British Interplanetary Society; vol. 27
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  • 46
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    Microcraters formed in glass by projectiles of various densities (1974)
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    Publication Date: 2011-08-16
    Description: An experiment was conducted investigating the effect of projectile density on the structure and size of craters in soda lime glass and fused quartz. The projectiles were spheres of polystyrene-divinylbenzene (PS-DVB), aluminum, and iron with velocities between 0.5 and 15 km/sec and diameters between 0.4 and 5 microns. The projectile densities spanned the range expected for primary and secondary particles of micrometer size at the lunar surface, and the velocities spanned the lower range of micrometeoroid velocities and the upper range of secondary projectile velocities. There are changes in crater morphology as the impact velocity increases, and the transitions occur at lower velocities for the projectiles of higher density. The sequence of morphological features of the craters found for PS-DVB impacting soda lime glass for increasing impact velocity, described in a previous work (Mandeville and Vedder, 1971), also occurs in fused quartz and in both targets with the more dense aluminum and iron projectiles. Each transition in morphology occurs at impact velocities generating a certain pressure in the target. High density projectiles require a lower velocity than low-density projectiles to generate a given shock pressure.
    Keywords: STRUCTURAL MECHANICS
    Type: Journal of Geophysical Research; 79; Aug. 10
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  • 47
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    Radiative transitions involving the /2p2/ 3Pe metastable autodetaching state of H- (1974)
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    Publication Date: 2011-08-16
    Description: A Hylleraas bound-state wave function and 1s-2s-2p close-coupling continuum wave functions are used to calculate the absorption coefficient for the free-bound transition of H(1s) + e + quantum to a H anion in (2p2,3Pe) and the differential emission rate for the inverse process. The absorption and emission spectral maximum is found to be at a photon wavelength of 1219.5 A, an improvement of 2 A on other calculations. This free-bound absorption process appears to be a significant source of continuous ultraviolet opacity.
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 191; Aug. 1
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  • 48
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    Electron-ion relaxation in a dense plasma (1974)
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    Publication Date: 2011-08-16
    Description: The microscopic physics of the thermonuclear runaway in highly degenerate carbon-oxygen cores is investigated to determine if and how a detonation wave is generated. An expression for the electron-ion relaxation time is derived under the assumption of large degeneracy and extreme relativity of the electrons in a two-temperature plasma. Since the nuclear burning time proves to be several orders of magnitude shorter than the relaxation time, it is concluded that in studying the structure of the detonation wave the electrons and ions must be treated as separate fluids.
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 191; Aug. 1
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  • 49
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    Rotational excitation of HCN by collisions (1974)
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    Publication Date: 2011-08-16
    Description: Rate constants for the rotational excitation of HCN by collisions with He atoms at temperatures below 100 K were computed from first principles and are presented in tabular form. The potential energy surface was obtained by using the uniform electron gas model of Gordon and Kim (1972) and then joined smoothly to the asymptotic long-range perturbation theory potential valid at large separations. Quantum close-coupling theory was used to analyze the collision dynamics. Individual rates are believed to be accurate to within 50% above 30 K and within a factor of two below 20 K. The results should be extendable to excitation by collision with H2 and may therefore be of value in the study of interstellar clouds.
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 191; Aug. 1
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  • 50
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    Prediction of radio structure in the two largest redshift QSOs (1974)
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    Publication Date: 2011-08-16
    Description: The radio spectral data of OH471 and OQ172 are shown in a graph along with decompositions of the spectra into canonical self-absorbed synchrotron components. The minimum number of canonical components consistent with the data is used. Theoretically expected angular radii and time scales are presented in a table. The estimation of the angular size of a compact radio source with known spectral form rests upon the establishment of its maximum brightness temperature.
    Keywords: SPACE SCIENCES
    Type: Nature; 250; Aug. 9
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  • 51
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    Automatic numerical generation of body-fitted curvilinear coordinate system for field containing any number of arbitrary two-dimensional bodies (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: A method for automatic numerical generation of a general curvilinear coordinate system with coordinate lines coincident with all boundaries of a general multi-connected region containing any number of arbitrarily shaped bodies is presented. With this procedure the numerical solution of a partial differential system may be done on a fixed rectangular field with a square mesh with no interpolation required regardless of the shape of the physical boundaries, regardless of the spacing of the curvilinear coordinate lines in the physical field, and regardless of the movement of the coordinate system. Numerical solutions for the lifting and nonlifting potential flow about Joukowski and Karman-Trefftz airfoils using this coordinate system generation show excellent comparison with the analytic solutions. The application to fields with multiple bodies is illustrated by a potential flow solution for multiple airfoils.
    Keywords: AERODYNAMICS
    Type: Journal of Computational Physics; 15; July 197
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    Approximate techniques of structural reanalysis (1974)
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    Publication Date: 2011-08-16
    Description: A study is made of two approximate techniques for structural reanalysis. These include Taylor series expansions for response variables in terms of design variables and the reduced-basis method. In addition, modifications to these techniques are proposed to overcome some of their major drawbacks. The modifications include a rational approach to the selection of the reduced-basis vectors and the use of Taylor series approximation in an iterative process. For the reduced basis a normalized set of vectors is chosen which consists of the original analyzed design and the first-order sensitivity analysis vectors. The use of the Taylor series approximation as a first (initial) estimate in an iterative process, can lead to significant improvements in accuracy, even with one iteration cycle. Therefore, the range of applicability of the reanalysis technique can be extended. Numerical examples are presented which demonstrate the gain in accuracy obtained by using the proposed modification techniques, for a wide range of variations in the design variables.
    Keywords: STRUCTURAL MECHANICS
    Type: Computers and Structures; 4; Aug. 197
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    Ozone and the polar hood of Mars (1974)
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    Publication Date: 2011-08-16
    Description: Ozone co-appears with the clouds of the polar hood in the winter hemisphere of Mars, but each is variable from day to day and location to location. Both the appearance of ozone and the polar hood clouds correlate with the temperature of the atmosphere which varies from day to day and location to location. A cold, clean, dry atmosphere is conducive to the formation of ozone.
    Keywords: SPACE SCIENCES
    Type: Icarus; 22; June 197
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    Possible H2/+/ ultraviolet spectrum of Jupiter (1974)
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    Publication Date: 2011-08-16
    Description: An ultraviolet spectral probe for a hydrogen-rich planetary atmosphere, such as that of Jupiter, is suggested, utilizing discrete lines in the H2(+) 2p pi u - /s sigma g electronic transition. For the Jovian atmosphere, the dominant mechanism for exciting H2(+) to its 2p pi u state appears to be photoexcitation, principally through absorption of the solar Lyman-alpha line. The critical role of corrections to the Born-Oppenheimer approximation in the use of an H2(+) probe is discussed.
    Keywords: SPACE SCIENCES
    Type: Icarus; 22; June 197
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    Models of the giant planets (1974)
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    Publication Date: 2011-08-16
    Description: Models of the giant planets were constructed based on the assumption that the hydrogen to helium ratio is solar in these planets. This assumption, together with arguments about the condensation sequence in the primitive solar nebula, yields models with a central core of rock and possibly ice surrounded by an envelope of hydrogen, helium, methane, ammonia, and water. These last three volatiles many be individually enhanced due to condensation at the period of core formation. Jupiter was found to have a core of about 40 earth masses and a water enhancement in the atmosphere of about 7.5 times the solar value. Saturn was found to have a core of 20 earth masses and a water enhancement in the atmosphere of about 25 times the solar value. Rock plus ice constitute 75-85% of the mass of Uranus and Neptune.
    Keywords: SPACE SCIENCES
    Type: Icarus; 22; June 197
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  • 56
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    Analysis of propagation of waves of acoustic frequencies in curved ducts (1974)
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    Publication Date: 2011-08-16
    Description: The propagation of waves of acoustic frequencies in curved ducts of rectangular cross section is studied for the first four modes. The analysis makes use of Bessel functions of the order (n + 1/2) to construct curves of wavenumber in the duct versus imposed wavenumber and to determine the profile of vibrational velocities. A wide range of duct widths and unrestricted radii of curvature have been considered. The characteristics of motion in a bend are compared with propagation of waves in a straight duct, and important differences in the behavior of waves are noted.
    Keywords: AERODYNAMICS
    Type: Acoustical Society of America; vol. 56
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    Axial flow measurements in trailing vortices (1974)
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    Publication Date: 2011-08-16
    Description: A scanning laser Doppler velocimeter was used to measure the axial velocity defect in the cores of trailing vortices behind a lifting airfoil of rectangular planform. Data were obtained at several different angles of attack and downstream distances ranging from 30 to 1000 chord lengths. The test was designed to obtain continuous data from the near field into the far field while removing uncertainties associated with the interpretation of data obtained by the hydrogen bubble technique. The measured velocities of V sub x/U sub infinity are compared with those predicted. The agreement is remarkably good over the entire range of downstream distances, which supports the credibility of calculating axial velocities using the results of Moore and Saffman (1973).
    Keywords: AERODYNAMICS
    Type: AIAA Journal; 12; Aug. 197
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  • 58
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    Roche limit of a solid body (1974)
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    Publication Date: 2011-08-16
    Description: Tidal fission of both impacting and orbiting linear elastic solid bodies based on Kelvin's theory of earth tides is considered. It is shown that there can be more than one mutually exclusive modes of fracture - the particular mode in which a body fractures depending on its size and strength. The analysis gives a vivid picture of the propagation of the fracture with a decreasing distance from the planet. Expressions for the initiation and completion of fracture are obtained which are displayed graphically for a rigid body. The effect of elasticity on the breakup altitude is discussed. For orbiting solid bodies, the study gives the upper limit of the breakup altitude as 0.38R (where R is the radius of planet), which is much less than the value 1.44R used for such bodies in the past. The results presented include a previously given theory by Sekiguchi as a part. For the special case of a liquid body, comparison is made with Roche's calculation and the difference explained.
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 191; July 15
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    Energy source for comet outbursts (1974)
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    Publication Date: 2011-08-16
    Description: Development of a mechanism explaining the internal source of energy of comet outbursts. A mechanism is proposed which automatically provides a source of particulate matter which creates a huge surface area which contains a substantial percentage of amorphous ice, so that the phase transition of the amorphous ice to a cubic structure provides a release of energy which may be responsible for the outbursts observed in many comets. In addition, the volume into which the transition can propagate is estimated for a spherical comet with a radius of 5 km.
    Keywords: SPACE SCIENCES
    Type: Nature; 250; July 26
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  • 60
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    On Jupiter's rate of rotation (1974)
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    Publication Date: 2011-08-16
    Description: It is suggested that the apparent lag of Jupiter's mean rotation rate in extratropical latitudes (System II) behind the rotation rate of Jupiter's radio emissions (System III) is caused by the difference between phase speeds and true speeds in extratropical latitudes. An estimate of the difference based on the formula for the phase speed of Rossby waves agrees with the difference calculated from the two rotation rates.
    Keywords: SPACE SCIENCES
    Type: Journal of the Atmospheric Sciences; 31; July 197
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    350-micron mapping of the Orion molecular cloud (1974)
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    Publication Date: 2011-08-16
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 191; July 1
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    Neutron propagation and 2.2 MeV gamma-ray line production in the solar atmosphere (1974)
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    Publication Date: 2011-08-16
    Description: Calculation of the 2.2-MeV gamma-ray line intensity from the sun using a Monte Carlo method for neutron propagation in the solar atmosphere. Detailed results are provided concerning the total gamma-ray yield per neutron and the time profile of the 2.2-MeV line from an instantaneous and monoenergetic neutron source. The parameters which have the most significant effects on the line intensity are the energies of the neutrons, the position of the neutron source on the sun, and the abundance of He-3 in the photosphere. For an isotropic neutron source which is not too close to the limb of the sun, the gamma-ray yield is between about 0.02 to 0.2 photons per neutron, provided that the neutron energies are in the range from 1 to 100 MeV and the ratio He-3/H is less than about .00005.
    Keywords: SPACE SCIENCES
    Type: Solar Physics; 36; May 1974
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    The atmosphere of Titan (1974)
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    Publication Date: 2011-08-16
    Description: Review of the currently available knowledge on Titan's atmosphere, based on the report of the 1973 Titan Atmosphere Workshop. The atmosphere composition, clouds, haze, and thermal structure are discussed, along with the photochemistry, escape, and recycling of the atmosphere.
    Keywords: SPACE SCIENCES
    Type: Icarus; 22; May 1974
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    Interstellar scattering of the Vela pulsar (1974)
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    Publication Date: 2011-08-16
    Description: The frequency dependence of the parameters of interstellar scattering between 837 and 8085 MHz for the Vela pulsar are consistent with thin-screen models of strong scattering. The magnitudes of the parameters indicate an anomalous turbulence along the path when they are compared with results for other pulsars with comparable column densities of free electrons in the line of sight. This anomaly is due presumably to the Gum Nebula. The decorrelation frequency, appropriately defined, is related to the pulse broadening time by 2 pi as predicted theoretically.
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 190; June 15
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    Infrared observations of Phobos from Mariner 9 (1974)
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    Publication Date: 2011-08-16
    Description: Radiometric measurements of Phobos at 10 and 20 microns show that the surface is covered by a material whose conductivity is extremely low, around .000001 cal per cm per sec per deg K. It is concluded that Phobos is covered with a layer of dust at least 1 mm thick.
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 190; June 1
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    Jupiter's clouds - Equatorial plumes and other cloud forms in the Pioneer 10 images (1974)
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    Publication Date: 2011-08-16
    Description: The imaging photopolarimeter experiment aboard the Pioneer 10 spacecraft produced two-dimensional maps of intensity and polarization in red and blue light at high resolution during flyby of Jupiter in December 1973. The present article describes cloud forms seen in the equatorial zone and compares them with rotational periods as a function of latitude derived from earth-based observations of features on Jupiter. A striking new feature consists of a bright, well-defined nucleus in the equatorial zone, with a plume apparently drawn out from the core of the nucleus.
    Keywords: SPACE SCIENCES
    Type: Science; 184; June 21
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    Vortex measurements behind a swept wing transport model (1974)
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    Publication Date: 2011-08-16
    Description: A backscatter laser Doppler velocimeter which simultaneously senses the axial and the tangential components of the velocity has been used to measure the velocity distributions in the near wake of a swept wing semispan transport model in a wind tunnel. The model configuration included nacelles, pylons, antishock bodies, and wing flaps which could be deflected 27 deg. Typical wake vortex velocity profiles are presented for the flaps-retracted and the flaps-deployed 27 deg configurations, respectively.
    Keywords: AERODYNAMICS
    Type: Journal of Aircraft; 11; June 197
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    Convection in the moon - Effect of variable viscosity (1974)
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    Publication Date: 2011-08-16
    Description: This work determines criteria for stability of the lunar interior to thermal convection in the case of variable viscosity. The conditions necessary for solid convection to play an important role in the moon's revolution are determined by application of the calculated stability criteria to a variety of thermal history models. Most thermal history temperature profiles would be unstable to solid convection at the present time, if currently used estimates of the viscosity function are applicable. A possible explanation of lunar seismic data is that temperatures near the melting point of silicates exist at depths greater than 800 km. If this is the case, either the lunar interior is stable, or solid convection is occurring at a rate insufficient to cool the lunar interior substantially. If the former is true, the viscosity of lunar material is higher than that usually assumed.
    Keywords: SPACE SCIENCES
    Type: Journal of Geophysical Research; 79; July 10
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  • 69
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    Thermophysical properties of lunar media. II - Heat transfer within the lunar surface layer (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Heat transfer within the lunar surface layer depends on several thermophysical properties of the lunar regolith, including the thermal conductivity, the specific heat, the thermal diffusivity, and the thermal parameter. Results of property measurements on simulated lunar materials are presented where appropriate as well as measurements made on the actual samples themselves. The variation of temperature on the moon with depth is considered, taking into account various times of the lunar day. The daily variation in temperature drops to about 1 deg at a depth of only 0.172 meters. The steady temperature on the moon below this depth is 225 K.
    Keywords: SPACE SCIENCES
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  • 70
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    Behaviour of comet Kohoutek /1973f/ (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The spectral identification of CH3CN and HCN provides the first support for the hypothesis first proposed by Wurm (1943), of chemically stable 'parent molecules' for the less stable radicals and ions seen in the coma and the tail. These two molecules were among the earliest discovered in dense interstellar clouds. Circumstantial evidence for the presence of water as the dominant volatile component in the nucleus has been growing for some time. However, a much more volatile species is required to explain the observed behavior of the comet. CO, formaldehyde, or methane would quickly evaporate as the comet approached the sun.
    Keywords: SPACE SCIENCES
    Type: Nature; 249; June 7
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  • 71
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    One- and multi-component models of the upper photosphere based on molecular spectra. II - CN/1, 1/ of the CN violet system (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: SPACE SCIENCES
    Type: Solar Physics; 35; Apr. 197
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  • 72
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    Hydrogen ionization in the shock layer for entry into the outer planets (1974)
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    Publication Date: 2011-08-16
    Description: Approximate assessments are presented for the chemical state of the shock layer with respect to the hydrogen ionization reaction for representative entries into Saturn, Uranus, and Jupiter. It is shown that, except for a steep entry into the Saturn nominal atmosphere, the computation of all entry probe gascaps for the outer planets can probably be considered on either a frozen or chemical equilibrium basis.
    Keywords: SPACE SCIENCES
    Type: AIAA Journal; 12; June 197
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  • 73
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    A ten-day observation of Hercules X-1 from the OSO-7 satellite (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The MIT X-ray detectors aboard the OSO-7 spacecraft viewed Hercules X-1 from November 14 to 24, 1972. X-ray turn-on in the 35-day cycle was observed to occur between phases 0.67 and 0.70 (November 18.64-18.70). A significant decrease in the X-ray intensity occurred near mid-orbital phase, approximately 1.5 days after X-ray turn-on. Using the 1-6 keV data obtained during the 35-day off state, we conclude that if the optical light curve is due to heating of the large star by a blackbody source of soft X-rays, then the source must be large (radius greater than 5,000 km) and cool (temperature (kT) less than 90 eV). During one eclipse period (November 20.8-21.0) we find evidence for 1-6 keV X-ray emission.
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 188; Feb. 15
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  • 74
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    Depletion of interstellar sodium and calcium (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: New measurements of the Ca II/Ca I ratios in interstellar clouds lead to the conclusion that not only Ca, but also Na, is underabundant in these regions. Recent calculations of element depletion by accretion of atoms onto dust grains probably cannot account for the observed abundance range. The extreme underabundance of Ca, and some part of the abundance range, probably reflect the composition of the grain cores.
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 187; Feb. 1
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  • 75
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    Static, stability, and dynamic analysis of shells of revolution by numerical integration - A comparison (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Recent innovations in digital computer technology have enabled engineers to analyze shell structures of complex configurations without unduly restrictive approximations. An attempt is made to compare the various programs now generally available from the point of view of the advantages of the relative technique utilized, as well as the programmed state of the art. Many of the comparisons are based on the sample problems solved by the STARS-2 system of programs. These examples indicate both the structural detail which can be analyzed by, and the analytical capabilities available in, the numerical shell-of-revolution programs. All advantages and differences are demonstrated by use of solutions for realistic shell problems in the areas of statics, stability, vibrations, and dynamic response of shells subjected to time-dependent loadings.
    Keywords: STRUCTURAL MECHANICS
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  • 76
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    Millisecond temporal structure in Cygnus X-1 (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 189; Apr. 1
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  • 77
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    Statistical time-dependent model for the interstellar gas (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: We present models for temperature and ionization structure of low, uniform-density (approximately 0.3 per cu cm) interstellar gas in a galactic disk which is exposed to soft X rays from supernova outbursts occurring randomly in space and time. The structure was calculated by computing the time record of temperature and ionization at a given point by Monte Carlo simulation. The calculation yields probability distribution functions for ionized fraction, temperature, and their various observable moments. These time-dependent models predict a bimodal temperature distribution of the gas that agrees with various observations. Cold regions in the low-density gas may have the appearance of clouds in 21-cm absorption. The time-dependent model, in contrast to the steady-state model, predicts large fluctuations in ionization rate and the existence of cold (approximately 30 K), ionized (ionized fraction equal to about 0.1) regions.
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 189; Apr. 1
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  • 78
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    Magnetic remanence mechanisms in iron and iron-nickel alloys, metallographic recognition criteria and implications for lunar sample research (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: SPACE SCIENCES
    Type: The Moon; 9; Mar
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  • 79
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    Laboratory simulation of the herringbone pattern associated with lunar secondary crater chains (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: V-shaped ridge components of the herringbone pattern associated with lunar secondary crater chains have been simulated by simultaneous and nearly simultaneous impact of two projectiles near one another. The impact velocities and angles of the projectiles were similar to those of the fragments that produced secondary craters found at various ranges from large lunar craters. Variables found to affect the included angles of the V-shaped ridges are: relative time of impact of the projectiles, impact angle, relative projectile mass, and azimuth angle of the crater chain relative to the projection of the flight line onto the target surface. The functional relationships between the forms of the ridges and many of these variables are similar to those observed for lunar V-shaped ridges. Comparison of the magnitudes of the ridge angles of both laboratory crater pairs and secondary crater chains of the crater Copernicus implies that material was ejected from Copernicus at angles in excess of 60 deg, measured from the normal, to form many of Copernicus' satellite craters.
    Keywords: SPACE SCIENCES
    Type: The Moon; 9; Mar
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  • 80
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    Possible lunar ring dikes (1974)
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    Publication Date: 2011-08-16
    Description: A search for lunar features that showed characteristics of terrestrial ring dikes was conducted, using the Lunar Orbiter series of photographs. Features exhibiting one or more of the following four criteria were included as lunar analogs to terrestrial ring dikes: (1) inner ridges approximately concentric with the crater wall, (2) inner rills approximately concentric with the crater wall, (3) outer ridges and/or rills approximately concentric with the crater wall, and (4) interior and exterior slopes of the crater wall approximately equal. Features exhibiting each of the four criteria were found, and some had combinations of two or more including rills merging into ridges - e.g., in Taruntius and Posidonius. Gambart is an example of equal inner and outer slopes, while Hesiodus A and Marth are two of the best examples of complete inner rings concentric with the outer rings. Ten per cent of the candidates were probable impact craters but had subsequent volcanic activity of a ring dike nature. The initial search showed a distribution of the possible lunar ring dikes that was nonrandom and strongly associated with the margins of the maria, further implying that they are volcanic features.
    Keywords: SPACE SCIENCES
    Type: The Moon; 9; Mar
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  • 81
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    The nature of microturbulence in the solar photosphere (1974)
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    Publication Date: 2011-08-16
    Description: It is shown that the increase in apparent Doppler width as the limb is approached is a natural consequence of the fact that the solar atmosphere is not homogeneous. The work on the sodium D line cores which assumes the solar atmosphere to be homogeneous is reviewed. It appears that the cores of the sodium D lines have been distorted by fluctuations in the solar atmosphere in a systematic manner. It is concluded that the increase in apparent Doppler width observed in the sodium D line is a natural consequence of the temperature fluctuations in the solar atmosphere. The presence of a velocity field is not required to produce this effect.
    Keywords: SPACE SCIENCES
    Type: Royal Astronomical Society; vol. 166
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  • 82
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    Two new physical processes in the far-ultraviolet spectrum of zeta Tauri (1974)
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    Publication Date: 2011-08-16
    Description: We have detected absorption features in the far-ultraviolet spectrum of zeta Tau (B3pe), one of which corresponds to a new transition involving quasi-H/-/, and the other to a transition involving quasi-H2/+/. The former transition produces a broad absorption feature on the red wing of L-alpha. It is the result of the absorption of a photon by a ground-state hydrogen atom and colliding electron, and it leads to the excitation of both electrons to the 2p2 3Pe state of H/-/.
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 187; Jan. 1
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  • 83
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    Atmosphere of Venus: Implications of Venera 8 sunlight measurements (1974)
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    Publication Date: 2011-08-16
    Description: Venera 8 measurements of solar illumination within the atmosphere of Venus are quantitatively analyzed by using a multilayer model atmosphere. The analysis shows that there are at least three different scattering layers in the atmosphere of Venus and the total cloud optical thickness is about 10 or greater. However, because of the nature of the observations, it is not possible to determine the vertical distribution of absorbed solar energy, which would reveal the drive for the atmospheric dynamics and the strength of the greenhouse effect. Future spacecraft observations should be designed to (1) measure both upward and downward solar fluxes, (2) include measurements of the highest cloud layers, and (3) employ narrow-band and broad-band sensors.-
    Keywords: SPACE SCIENCES
    Type: Science; 184; May 31
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  • 84
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    Forced vibrations of multi-component compliant tanks and feedlines (1974)
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    Publication Date: 2011-08-16
    Description: An analytical and experimental research program was performed to investigate the effects of flexible tanks and lines and the total system dynamic response of a simple physical system which had some of the essential features of a liquid-fueled launch vehicle. Several vessel-wall materials were used to obtain a range of elastic moduli. Water was used to simulate the fuel and an electromagnetic shaker provided external excitation such as might originate from a rocket-propulsion system. Experimental data were compared to values obtained from mathematical models for the many degree-of-freedom lumped-mass representation.
    Keywords: STRUCTURAL MECHANICS
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  • 85
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    Profiles of emission lines in Be stars. III (1974)
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    Publication Date: 2011-08-16
    Description: The long-period V/R emission variations in three Be stars, HD 20336, 25 Ori, and beta-one Mon have been studied according to the mathematical formulation of the eccentric rotating model presented in a previous paper. The predictions of the theory fit satisfactorily the general trend of observed data. Periods, eccentricities, and sizes of the emitting ring with respect to the stellar radius are thereby derived and found to be consistent with results of the previous investigation of 105 Tauri.
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 189; May 1
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  • 86
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    The local complex of O and B stars. I - Distribution of stars and interstellar dust (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The O-B5 stars, supergiants, young clusters, and associations within 1 kpc of the sun populate two flat systems inclined to each other by 19 to 22 deg. The historical background, statistical significance, composition, spatial arrangement of the contents, and interstellar extinction in the two belts are discussed. A more or less random distribution in space and in age characterizes the O-B5 stars of the 'galactic belt', which is aligned nearly along the Milky Way. The 'Gould belt' is inclined to the Milky Way (north in Sco-Oph and south in Orion), and exhibits a projected distribution of O-B5 stars in its mean plane that resembles a 'dragonfly', with five major features defining it. A crude 'diameter' of the system is 750 to 1000 pc, and the sun's position is eccentric, lying toward Ophiuchus. The nuclear age of the system, while not unique, may be characterized as 30 m.y. from the spectral type of the broad main-sequence turnup near B2-5. Most of the O-B2 stars and youngest stellar groups near the sun belong to the Gould belt, but both belts have approximately equal space densities of B3-B5 stars and similar average values of interstellar extinction.-
    Keywords: SPACE SCIENCES
    Type: Astronomical Journal; 79; Apr. 197
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  • 87
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    Solar coronal line profiles in the extreme-ultraviolet (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 189; Apr. 1
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  • 88
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    Galactic arm structure and gamma-ray astronomy (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: In an attempt to explain the observed unexpectedly high-energy gamma-radiation over a broad region of the galactic plane in the general direction of the galactic center, a model is proposed wherein the galactic cosmic rays are preferentially located in the high-matter-density regions of galactic arm segments, as a result of the weight of the matter in these arms tying the magnetic fields and hence the cosmic rays to these regions. The presently observed longitudinal distribution of galactic gamma-rays can be explained with the current estimate of the average galactic matter density, if the average ratio of arm to interarm matter is 5:1 for the major arm segments toward the galactic center from the sun, and if the cosmic-ray density normalized to its local value is assumed to be directly proportional to the matter density.
    Keywords: SPACE SCIENCES
    Type: Astrophysical Journal; 189; Apr. 15
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  • 89
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    The atmosphere of Mars (1974)
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    Publication Date: 2011-08-16
    Description: The atmosphere of Mars is essentially a pure carbon dioxide atmosphere that contains a small and seasonably varying amount of water vapor. A number of minor constituents which arise from the interactions of solar radiation with water vapor and carbon dioxide include carbon monoxide, atomic oxygen, molecular oxygen, ozone, and atomic hydrogen. At the surface of Mars the atmospheric pressure is less than one hundredth of the pressure at the surface of the earth. Extensive cloud systems appear on Mars. The structure of the lower Martian atmosphere is discussed together with variations in the lower atmosphere and the characteristics of the upper atmosphere. Reactions of photochemistry are considered along with the atmospheric escape and interactions between the atmosphere and the polar caps.
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  • 90
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    Modified Brans-Dicke gravitational theory with nonzero divergence of the energy-momentum tensor (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The Brans-Dicke theory of gravitation is modified by assuming that the divergence of the energy-momentum tensor is proportional to the covariant derivative of the scalar curvature. No ad hoc additions to the usual Brans-Dicke field equations are required as in Rastall's modification of the Einstein theory or as in the steady-state theories, of which this is a natural possibility. Three parameters emerge from the theory - namely, the unnormalized gravitational constant, the usual Brans-Dicke parameter, and the proportionality constant. In the post-Newtonian approximation, these parameters can be fixed by experiment. However, there exists a certain choice of the parameters for which the theory reduces to an Einstein theory with constant scalar curvature.
    Keywords: SPACE SCIENCES
    Type: Physical Review D - Particles and Fields; vol. 9
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  • 91
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    Correlation between region of enhanced mare flooding on the lunar farside and Apollo orbital results (1974)
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    Publication Date: 2011-08-16
    Keywords: SPACE SCIENCES
    Type: The Moon; 9; Mar
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  • 92
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    Square-root algorithm for evaluating mismodeled process noise (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: As the application of sequential filters has grown, the need has arisen to evaluate the sensitivity of these filters to mismodeling of the random process. A numerically reliable square-root algorithm is developed for calculating the covariances of estimates from a sequential filter which incorrectly models process noise. Mismodeling is restricted to the correlation time and standard deviation of a random process represented as a first-order Gauss-Markov sequence. Using a computer program which employs this algorithm, a sensitivity analysis was performed for several types of earth-based tracking data from an interplanetary spacecraft.
    Keywords: SPACE SCIENCES
    Type: Journal of Spacecraft and Rockets; 11; Apr. 197
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  • 93
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    On the mass determination of collapsed objects in close binaries - Applications to black-holes and neutron stars (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Keywords: SPACE SCIENCES
    Type: Astrophysics and Space Science; 27; Apr. 197
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  • 94
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    Evidence about hydrate and solid water in the Martian surface from the 1969 Mariner infrared spectrometer (1974)
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    Publication Date: 2011-08-16
    Description: Results of laboratory simulation studies and comparative computer analyses of infrared spectral data regarding the presence, distribution, and form of condensed-phase water in the Martian surface. The data were obtained with the aid of the Mariner 6 and 7 spacecraft which were equipped with infrared spectrometers recording the infrared spectrum from 1.9 to 14.4 microns. From the analysis of these data evidence is obtained which signifies some sort of compositional and/or particle size variability of the extent and nature of hydration. Changes are noted which could be due to ice thinly covering a small fraction of the planetary surface in particularly cold spots, possibly on partially shaded slopes. At southerly latitudes, the fraction so covered seems to increase as the polar cap edge is approached. It is therefore concluded that there is strong evidence of ice formation on the planetary surface at the edge of the polar cap.
    Keywords: SPACE SCIENCES
    Type: Journal of Geophysical Research; 79; Apr. 10
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  • 95
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    Mariner 10 pictures of Mercury - First results (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Mercury has a heavily cratered surface containing basins up to at least 1300 kilometers diameter flooded with mare-like material. Many features are closely similar to those on the moon, but significant structural differences exist. Major chemical differentiation before termination of accretion is implied.
    Keywords: SPACE SCIENCES
    Type: Science; 184; Apr. 26
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  • 96
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    The Toulon meteorite - A new chondrite from Illinois (1974)
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    Publication Date: 2011-08-16
    Description: Toulon is an olivine-bronzite chondrite found near Toulon, Illinois in 1962. It contains abundant, well preserved chondrules, as well as glasses that are not well devitrified. Most of the metal has been weathered out. Olivine and pyroxene are well equilibrated. It has been classified as an H5 chondrite.
    Keywords: SPACE SCIENCES
    Type: Meteoritics; 9; Mar. 30
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  • 97
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    Photometry of Comet Kohoutek /1973f/ (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Data are reported which provide the first large, homogeneous set of photoelectric and infrared photometry obtained for any comet. Assuming an albedo of 0.5 (a high albedo is assumed because of the large ratio of gas to dust in Kohoutek), the diameter of the nucleus of the comet is estimated to be 10 to 15 km. Based on a comparison with the infrared spectrum of Comet Bennett, it was calculated that the latter had about 16 times as much dust as Kohoutek. The data are used to obtain an evaluation of O'Dell's (1971) expression for the albedo of cometary dust grains in terms of the integrated infrared surface brightness and the surface brightness of scattered light in the continuum.
    Keywords: SPACE SCIENCES
    Type: Nature; 248; Apr. 26
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  • 98
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    Creation of an artificial lunar atmosphere (1974)
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    Publication Date: 2011-08-16
    Description: It is pointed out that the tenuous nature of the lunar atmosphere is maintained by rapid loss of gases released at the lunar surface. The loss of gases from the lunar atmosphere in the case of a greatly increased atmospheric density is investigated. It is found that in the case of such an increase in the density of the lunar atmosphere, a point can be reached where loss occurs so slowly that it is negligible over human time scales. In the event an artificial lunar atmosphere were to be created, gases can be obtained by heating or vaporization of the lunar soil. This could be done with the aid of nuclear devices.
    Keywords: SPACE SCIENCES
    Type: Nature; 248; Apr. 19
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  • 99
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    Nonproportional loading limit for structures (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: The design of most structures involves ensuring integrity for several independent loading conditions. Often, it is rational to design these, exploiting the ductility of the materials to reduce structural costs. Then, ensuring integrity evokes the need for nonmonotonic limit analyses. A groundwork is laid for implementing these analyses. An alternate limit load characterization to that of Greenberg is provided, a mathematical statement of the problem leading to both monotonic (proportional) and nonmonotonic limit loads values is formulated, a direct limit load analysis procedure for analysis within a finite-element framework is described, and limit loads for sets of simple structures are evaluated. A direct limit analysis process is described, and monotonic limit loads are characterized. The process furnishes 'exact' values of limit loads with increasing efficiency as the number of structural elements and force redundancy decreases. Tests show that the accuracy of predicting nonmonotonic limit loads is very sensitive to the number of degrees of freedom in the analysis compared with the total number in the model.
    Keywords: STRUCTURAL MECHANICS
    Type: Computers and Structures; 4; Mar. 197
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  • 100
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    The galloping chromosphere (1974)
    In:  Other Sources
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    Publication Date: 2011-08-16
    Description: Oscillating velocity fields can be observed on H-alpha filtergrams as a shifting pattern of intensity fluctuations known as 'the galloping chromosphere'. The characteristics of this activity are those of horizontal running waves of typical period of about 300 sec and long wavelength (about 20,000 km) that can be interpreted as acoustic-gravity waves propagating in the acoustic domain. Periods are longer in dark, structured regions, and in fibrils, and the change is quantitatively consistent with the reduction of resonance frequency in a magnetic field of 1 to 10 gauss. These easily observed fluctuations thus offer a means of estimating magnetic-field strength at specific locations in the chromosphere. Phase velocities are high, ranging upward from typical values between 50 and 100 km per sec, and tending to be lower in active regions and toward the limb.
    Keywords: SPACE SCIENCES
    Type: Solar Physics; 35; Mar. 197
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