Search NASA⌕ Search

SEARCH · Search NASA

Results for “HIGH INTENSITY”

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.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

The multiple junction edge illuminated solar cell

The multiple junction edge illuminated solar cell (M-J Cell) was devised for high voltage, low current applications. Devices to be flight-tested in early 1974 with 96 series-connected PNN+ junctions in a 2 cm x 2.3 cm size deliver 36 volts at 1 milliampere. Test data of M-J Cells fabricated with resistivities of 10, 50, 100, 200, 450, and 1000 ohm-cm silicon are presented and problem areas are discussed. An additional potential application of the M-J Cell lies in utilization of its high-intensity performance that has been demonstrated at levels in excess of 100 AMO suns.

Sater, B. L.↗
NASA NTRS1974

Jupiter's magnetosphere as observed with Pioneer 10

During November and December 1973 the spacecraft Pioneer 10 provided the first in situ observations of energetic particles in the magnetosphere of Jupiter. Observations made with a University of Iowa instrument are reported. It is found that Jupiter's magnetosphere consists of two quite different parts. The outer magnetosphere has the form of a thin, disk-like, quasi-trapping region extending from about 20 to 100 planetary radii. The inner magnetosphere is characterized by a dipolar magnetic field and very high intensities of durably trapped energetic particles. Particle intensities throughout both regions are discussed, taking into account conditions at the orbits of Io, Europa, and Ganymede.

Van Allen, J. A.↗
NASA NTRS1974

Model systems for life processes on Mars

In the evolution of life forms nonphotosynthetic mechanisms are developed. The question remains whether a total life system could evolve which is not dependent upon photosynthesis. In trying to visualize life on other planets, the photosynthetic process has problems. On Mars, the high intensity of light at the surface is a concern and alternative mechanisms need to be defined and analyzed. In the UV search for alternate mechanisms, several different areas may be identified. These involve activated inorganic compounds in the atmosphere, such as the products of photodissociation of carbon dioxide and the organic material which may be created by natural phenomena. In addition, a life system based on the pressure of the atmospheric constituents, such as carbon dioxide, is a possibility. These considerations may be important for the understanding of evolutionary processes of life on another planet. Model systems which depend on these alternative mechanisms are defined and related to presently planned and future planetary missions.

Mitz, M. A.↗
NASA NTRS1976

The X-ray variability of Vela X-1 (3U 0900-40)

From observations of Vela X-1 with the MSSL 2.5-7.5 keV detector onboard Copernicus, the behavior of the source can be characterized by three phases: (1) high intensity, (2) low intensity, and (3) eclipse. Combining data from the 1972 Uhuru observations with eclipse observation yields a binary period of 8.963 + or - 0.001 days with zero phase on 1975 Feb. 6.97 + or - 0.04 UT. The low intensity phase is interpreted as being due to increased absorption in an accretion wake traveling across the line of sight (the spectral slope remains relatively constant throughout the cycle). Another period of enhanced absorption immediately after exit from eclipse may be due to a bow shock. Comparison of the two observations suggests that these structures vary from cycle to cycle and, since the orbital period is long, probably during each cycle.

Charles, P. A.↗
NASA NTRS1976

X-ray emission from high temperature plasmas

The physical processes occurring in plasma focus devices were studied. These devices produce dense high temperature plasmas, which emit X rays of hundreds of KeV energy and one to ten billion neutrons per pulse. The processes in the devices seem related to solar flare phenomena, and would also be of interest for controlled thermonuclear fusion applications. The high intensity, short duration bursts of X rays and neutrons could also possibly be used for pumping nuclear lasers.

Harries, W. L.↗
NASA NTRS1976

Method and apparatus for generating coherent radiation in the ultra-violet region and above by use of distributed feedback

Helium in the superfluid state emits copious amounts of radiation in the ultraviolet region when excited by an electron stream. Conventional laser action using mirrors is impossible in superfluid helium because there are no mirrors that will reflect VUV radiation. By utilizing the distributed feedback method, the superfluid helium can be made to lase. By setting up a standing wave in superfluid helium that has a wavelength equal to, or harmonically related to, half the wavelength of the photon radiation chosen to be emitted as laser radiation by the superfluid helium, the need for end mirrors to produce reflection of the laser radiation is eliminated and reflection occurs instead at the wavefronts of the standing wave. The photons leave the superfluid helium at right angles to the standing wave as coherent radiation having a very high intensity. The standing wave established in the superfluid helium may be an acoustical standing wave, a thermal standing wave (second sound), or an electric standing wave.

Saffren, M. M.↗
NASA NTRS1976

Investigation of applications for high-power, self-critical fissioning uranium plasma reactors

Analytical studies were conducted to investigate potentially attractive applications for gaseous nuclear cavity reactors fueled by uranium hexafluoride and its decomposition products at temperatures of 2000 to 6000 K and total pressures of a few hundred atmospheres. Approximate operating conditions and performance levels for a class of nuclear reactors in which fission energy removal is accomplished principally by radiant heat transfer from the high temperature gaseous nuclear fuel to surrounding absorbing media were determined. The results show the radiant energy deposited in the absorbing media may be efficiently utilized in energy conversion system applications which include (1) a primary energy source for high thrust, high specific impulse space propulsion, (2) an energy source for highly efficient generation of electricity, and (3) a source of high intensity photon flux for heating working fluid gases for hydrogen production or MHD power extraction.

Rodgers, R. J.↗
NASA NTRS1975

Soft X-ray search of centre of Cygnus Loop

Equipment on the Copernicus satellite has been used to search for evidence of a compact object in the center of the Cygnus Loop supernova remnant. Rocket measurements reported by Rappaport et al. (1973) indicate that a central object exists. However, the study conducted with the aid of the satellite was negative. This negative result could indicate that the X-ray source was simply not in its high-intensity mode at the time of observation, or could arise because the source is at some other location in the Loop.

Snyder, W. A.↗
NASA NTRS1976

Evidence for a 17-d periodicity from Cyg X-3

Data are presented from the Ariel-V All-Sky Monitor which indicate a 17-day periodicity of the X-ray spectra from Cyg X-3 (3U2030+40). The data are consistent with data from the Ariel V Sky Survey Experiment. Assuming that the high intensity state of Cyg X-3 is well fitted by a structureless black body (Serlemitsos et al., 1975), and that the 17-day maxima correspond to increased electron scattering in the source, it is suggested that the 17-day effect is analogous to the 35-day variation in Her X-1. The possible explanation of this phenomenon as a result of the 17-day orbital period of the binary system containing Cyg X-3 is severely constrained by the stability of the well-known 4.8-hour variation.

Holt, S. S.↗
NASA NTRS1976

Aeroacoustics: Acoustic wave propagation; Aircraft noise prediction; Aeroacoustic instrumentation

The papers in this volume deal with recent research into acoustic-wave propagation through the atmosphere and progress in aeroacoustic instrumentation, facilities, and test techniques. Topics include the propagation of aircraft noise over long distances in the lower atmosphere, measured effects of turbulence on the rise time of a weak shock, sound scattering from atmospheric turbulence, saturation effects associated with sound propagation in a turbulent medium, and a computer model of the lightning-thunder process. Other papers discuss the development of a computer system for aircraft noise prediction; aircraft flyover noise measurements; and theories and methods for the prediction of ground effects on aircraft noise propagation, for the prediction of airframe aerodynamic noise, for turbine noise prediction, and for combustion noise prediction. Attention is also given to the use of Hartmann generators as sources of high-intensity sound in a large absorption flow-duct facility, an outdoor jet noise facility, factors in the design and performance of free-jet acoustic wind tunnels, and the use of a laser shadowgraph for jet noise diagnosis.

Schwartz, I. R.↗
NASA NTRS1976

A device for rapid determination of thermophysical properties of phase-change wind-tunnel models

An experimental method for direct measurement of the thermophysical properties of wind tunnel heat transfer models was developed. The technique consists of placing the model under a bank of high intensity, radiant heaters so that the fast opening water cooled shutters, which isolate the heater bank from the model, allow a step-input heat rate to be applied. Measurements of the heat transfer rate coupled with a surface-temperature time history of the same material are sufficient to determine the material thermophysical properties. An infrared thermometer is used to measure model surface temperature and a slug calorimeter provides heat transfer rate information. The output from the infrared thermometer and calorimeter is then fed into an analog-to-digital converter which provides digitized data to a computer. This computer then calculates combined thermophysical properties and a teleprinter prints out all the data. Thus, results are available within 7 minutes of test initiation as opposed to the weeks or months required using prior techniques.

Creel, T. R., Jr.↗
NASA NTRS1977

The Influence of Forward Flight on Propeller Noise

The effect of flight on blade surface pressures and propeller noise was reported. There were significant differences in blade surface pressures and far-field noise between static and flight conditions. The static data showed many high-intensity, tone-like peaks whereas the flight data was generally free from tones. The turbulence ingested by the propeller operating statically was dominated by long, thin eddies. In flight the scale of the turbulence was greately reduced from that observed statically.

Magliozzi, B.↗
NASA NTRS1977

Experimental study of outdoor propagation of spherically speading periodic acoustic waves of finite amplitude

The outdoor propagation of spherically spreading sound waves of finite amplitude was investigated. The main purpose of the experiments was to determine the extent to which the outdoor environment, mainly random inhomogeneity of the medium, affects finite amplitude propagation. Periodic sources with fundamental frequencies in the range 6 to 8 kHz and source levels SPLlm from 140 to 149 dB were used. The sources were an array of 7 to 10 horn drivers and a siren. The propagation path was vertical and parallel to an 85 m tower, whose elevator carried the traveling microphone. The general conclusions drawn from the experimental results were as follows. The inhomogeneities caused significant fluctuations in the instantaneous acoustic signal, but with sufficient time averaging of the measured harmonic levels, the results were comparable to results expected for propagation in a quiet medium. Propagation data for the fundamental of the siren approached within 1 dB of the weak shock saturation levels. Extra attenuation on the order of 8 dB was observed. The measurements generally confirmed the predictions of several theoretical models. The maximum propagation distance was 36 m. The narrowbeam arrays were much weaker sources. Nonlinear propagation distortion was produced, but the maximum value of extra attenuation measured was 1.5 dB. The maximum propagation distance was 76 m. The behavior of the asymetric waveforms received in one experiment qualitatively suggested that beam type diffraction effects were present. The role of diffraction of high intensity sound waves in radiation from a single horn was briefly investigated.

Theobald, M. A.↗
NASA NTRS1976

Evaluation of nuclear-reactor-produced iodine-123

Iodine-123 has such great potential for nuclear medicine that all possible production methods should be considered. In this report, an experimental study related to I-123 production at a high-intensity fast-flux reactor using the reaction Xe-124(n,2n)Xe-123 is considered. The conclusion is that I-123 could be made in small quantities and the cost would be higher than the cyclotron methods presently used.

Blue, J. W.↗
NASA NTRS1977

Recurrent X-ray outbursts from Aquila X-1

Ariel V All-Sky Monitor observations of Aql X-1 are reported and compared with previous observations that indicate the existence of 'low' and 'high' intensity states. All the data considered are shown to be consistent with flaring episodes having a mean flare interval of 435 days with an rms scatter of about 10%. It is suggested that the observations are most easily interpreted in terms of an 'X-ray dwarf nova' binary of the type proposed for the transient X-ray source A0620-00. Constraints on more detailed features of the source model are discussed.

Kaluzienski, L. J.↗
NASA NTRS1977

Production

The manufacturing tasks and life support systems that would pertain to a space habitat located at the Lagrange equilibrium point L5 are examined. Aluminum and titanium could be obtained from the moon minerals anorthosite and ilmenite, respectively. Although hydrogen required for purifying the metals would probably have to be imported from earth, the L5 project should have abundant energy for the processing. Methods of utilizing various glasses and ceramics common in the moon are being investigated. Manufacturing processes, such as capillary brazing, ceramic melting, laser welding, and other techniques, are considered with respect to their suitability at zero gravity and in a vacuum. With regard to life support, high-intensity agriculture is discussed, with attention to the use of a mirror system to provide continuous illumination.

Hibbs, A. R.↗
NASA NTRS1977

Variability of LMC X-4

X-rays in the 2-11-keV band were detected from LMC X-4 using the rotating modulation collimator system on SAS-3. The derived X-ray luminosity of LMC X-4 is of the order of 10 to the 38th power ergs/s. A transition to a high-intensity state which lasted about 40 minutes was detected during which short-time-scale flares (about 20 s) were observed. The temporal and spectral behavior of LMC X-4 is found to be similar to that of several X-ray binaries. A derived 90% error circle with a radius of 1 arcmin is also presented.

Epstein, A.↗