Relativistic perturbed oscillator.
Relativistic perturbed oscillator, solving problem via canonical transformation
CANONICAL PROBLEM↗
SEARCH · Engineering Papers
Results for “particle methods”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Flash heating of seeded gases.
Radiative heating of H and He containing suspension of solid particle absorbers, noting proportionality between gas particle dispersion decrease and energy absorption
ENERGY ABSORPTION↗
Transport Coefficients of Ionized Gases
Chapman-Enskog transport collision integrals calculated for repulsive and attractive screened Coulomb potentials in ionized gases
COULOMB POTENTIAL↗
Systems of self-gravitating particles in general relativity and the concept of an equation of state
Equilibrium configurations of self-gravitating particles systems by self consistent fields method
Bonazzola, S.↗
Theoretical aspects of atomic collisions - Classical, variational, and Faddeev methods.
Atomic collision theory, discussing cross section calculations by Gryzinski classical method, variational methods and Fadeev equations for three particles
Gerjuoy, E.↗
Velocity synchronized Fourier transform hologram camera system
Hologram camera system recording hypervelocity particles by velocity synchronized Fourier transform method, employing interferometer
Dyes, W. A.↗
Prediction and measurement of radiation damage to CMOS devices on board spacecraft
The CMOS Radiation Effects Measurement (CREM) experiment is presently being flown on the Explorer-55, to evaluate device performance in the actual space radiation environment and to correlate the respective measurements to on-the-ground laboratory irradiation results. The experiment contains an assembly of CMOS and P-MOS devices shielded in front over 2 pi steradian by flat slabs of aluminum of 40, 80, 150, and 300 mils (1.02, 2.04, 3.81, and 7.62 mm) thicknesses, and by a practically infinite shield in the back. Initial results from the CREM experiment are reported. Predictions of radiation damage to CMOS devices are based on standard environment models and computational techniques. Measured space damage is smaller than predicted by about a factor of 2-3 for thin shields but agrees well with predictions for thicker shields. It is not clear at this time how the trapped particle environment models or the computational methods should be modified in order to achieve better agreement between experimental results and predicted damage curves.
Cliff, R. A.↗
Optical measurements of the droplet size distribution in the case of fuel atomization in swirl nozzles and planar airblast diffusers
The theoretical principles of optical methods for the determination of the particle sizes of sprays are considered and aspects of the experimental implementation of these principles are discussed. An experimental device for point-intensity measurements makes use of a helium-neon laser. The cross-sectional area of the laser beam is enlarged with the aid of a lens system to the size of the measurement cross-section. The intensity of the laser light scattered by the spray particles is measured as a function of light direction. Approaches which take into account the total energy of the diffractively scattered light are also discussed and an investigation is conducted regarding the measurement error sources. A description is presented of experimental results obtained in studies of a number of fuel nozzle sprays.
Kayser, A.↗
Cloud microphysics - Analysis of the clouds of Earth, Venus, Mars, and Jupiter
The probable microphysics of a cloud is deduced by a described method which requires information on cloud particle mean size, composition, number density, and atmospheric structure, but does not require any additional information. The analysis is applied to the sulfuric acid clouds of Venus, the water ice and dust clouds of Mars, and the ammonia-water and ammonia ice clouds of Jupiter. The Venus cloud layer is found to have some resemblance to smog and haze layers on earth. The water ice clouds on Mars resemble tenuous nonprecipitating cirrus clouds on earth. Precipitation, vertical distribution of gases, and vertical transport of heat in the clouds on Jupiter are considered.
Rossow, W. B.↗
Energy conservation - A test for scattering approximations
The roles of the extinction theorem and energy conservation in obtaining the scattering and absorption cross sections for several light scattering approximations are explored. It is shown that the Rayleigh, Rayleigh-Gans, anomalous diffraction, geometrical optics, and Shifrin approximations all lead to reasonable values of the cross sections, while the modified Mie approximation does not. Further examination of the modified Mie approximation for the ensembles of nonspherical particles reveals additional problems with that method.
Acquista, C.↗
Comparisons between geometrical optics and Lorenz-Mie theory
Both the Lorenz-Mie and geometrical optics theories are used in calculating the scattered light patterns produced by transparent spherical particles over a wide range of diameters, between 1.0 and 100 microns, and for the range of forward scattering angles from zero to 20 deg. A detailed comparison of the results shows the greater accuracy of the geometrical optics theory in the forward direction. Emphasis is given to the simultaneous sizing and velocimetry of particles by means of pedestal calibration methods.
Ungut, A.↗
Lunar rock surfaces as detectors of solar processes
Lunar rock surfaces exposed at or just below the lunar surface are considered as detectors of the solar wind, solar flares and solar-derived magnetic fields through their interactions with galactic cosmic rays. The degradation of the solar detector capabilities of lunar surface rocks by meteoroid impact erosion, accreta deposition, loose dust, and sputtering, amorphous layer formation and accelerated diffusion due to solar particles and illumination is discussed, and it is noted that the complex interactions of factors affecting the outer micron of exposed surface material has so far prevented the development of a satisfactory model for a particle detector on the submicron scale. Methods for the determination of surface exposure ages based on the accumulation of light solar wind noble gases, Fe and Mg, impact craters, solar flare tracks, and cosmogenic Kr isotopes are examined, and the systematic variations in the ages determined by the various clocks are discussed. It is concluded that a means of obtaining satisfactory quantitative rate or flux data has not yet been established.
Hartung, J. B.↗
Harmonic well matter densities and Pauli correlation effects in heavy-ion collisions
A generalized optical model heavy ion reaction theory is extended to include correlation effects between projectile and target constituents according to the Pauli exclusion principle. These correlation effects are significant for accurately predicting cross sections for projectile nucleus abrasions, but are relatively unimportant for determining total and absorption cross sections for heavy ion collisions. For lighter nuclei, predictive capabilities were also improved by developing an analytic method for extracting their nuclear single particle density distributions from experimentally measured harmonic well charge density distributions. This improved theory is compared with previous theoretical predictions and recent experimental results.
Townsend, L. W.↗
Electrophoresis tests on STS-3 and ground control experiments - A basis for future biological sample selections
Static zone electrophoresis is an electrokinetic method of separating macromolecules and small particles. However, its application for the isolation of biological cells and concentrated protein solutions is limited by sedimentation and convection. Microgravity eliminates or reduces sedimentation, floatation, and density-driven convection arising from either Joule heating or concentration differences. The advantages of such an environment were first demonstrated in space during the Apollo 14 and 16 missions. In 1975 the Electrophoresis Technology Experiment (MA-011) was conducted during the Apollo-Soyuz Test Project flight. In 1979 a project was initiated to repeat the separations of human kidney cells. One of the major objectives of the Electrophoresis Equipment Verification Tests (EEVT) on STS-3 was to repeat and thereby validate the first successful electrophoretic separation of human kidney cells. Attention is given to the EEVT apparatus, the preflight electrophoresis, and inflight operational results.
Morrison, D. R.↗
Comments on the measurements of multiple muon phenomena
The extensive air showers in the energy around 10 to the 15th power eV include those initiated by astrophysical primary gamma-rays. The observations need a precise measurement on the directions of primary particles. It is one of the methods to measure the directions of high-energy muons in air showers. The accuracy in measuring the direction, by calculating the cosmic-ray phenomena in the atmosphere at very high energy was investgated. The results calculated by Monte Carlo method suggest that one may determine the direction of primary cosmic-rays within errors of 10/3 rad in observing muons of above 100 GeV at sea level.
Sato, T.↗
Planetary astronomy: Rings, satellites, and asteroids
Studies of planetary rings focus on the dynamical processes that govern astronomically observable ring properties and structure. These investigations thus help reveal properties of the rings as well as probe the gravity fields of the planets. Satellite studies involve interpretation of orbital motion to extract information regarding the gravity fields of the outer planets and the physical properties of the satellites themselves. Asteroid lightcurve work is designed to investigate the large-scale shapes of the asteroids, as well as to reveal anomalous features such as major topography, possible satellites, or albedo variations. Work on the nature of viscous transport in planetary rings, emphasizing the role of individual particles' physical properties, has yielded a method for estimating both angular momentum and mass transport given an optical-thickness gradient. This result offers the prospect of ringlet instability, which may explain the square-profile ringlets in Saturn's C Ring. Thermal and reflected lightcurves of 532 Herculina have been interpreted to show that albedo variations cannot be the primary cause of variations. A lightcurve simulation has been developed to model complex asteroidal figures. Bamberga was observed during the December occultation as part of the joint LPL-Lowell program.
Greenberg, Richard↗
Digital image velocimetry
Digital image velocimetry is proposed for the measurement of the instantaneous velocity fields of time dependent flows. This technique improves the flow measurement by eliminating some of the restrictions on existing optical methods (i.e., laser speckle velocimetry and particle image velocimetry). Among these restrictions are the limited dynamic range of the velocity measurement, directional ambiguity of the velocity vector, and the difficulty of a real-time capability. The present technique greatly enhances the dynamic range of the velocity measurement and unequivocally determines the direction of the velocity vector.
Cho, Y.-C.↗
Light scattering instrumentation for micro gravity research
The analysis of light scattered from an ensemble of particles has long been a preferred method for characterizing their physical properties. Instrumentation to perform the measurements which forms the basis for such analysis is available in many forms based upon a variety of different experimental techniques. A system is presented which is singularly applicable for making many types of measurements in a microgravity environment. The commercial version of this device, the DAWN-F, has been used in many labs throughout the world to perform analyses of particular importance for both research and production. Light scattering theory is reviewed and the structure and function of the system is described.
Wyatt, Philip J.↗