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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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At least 1,099 records · Page 61
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NASA NTRS1975

Clusters in the distribution of pulsars in period, pulse-width, and age

The question of whether pulsars form a single group or whether pulsars come in two or more different groups is discussed. It is proposed that such groups might be related to several factors such as the initial creation of the neutron star, or the orientation of the magnetic field axis with the spin axis. Various statistical models are examined.

Baker, K. B.↗
NASA NTRS1976

A research project to develop and evaluate a technical education component on materials technology for orientation to space-age technology

A project was initiated to develop, implement, and evaluate a prototype component for self-pacing, individualized instruction on basic materials science. Results of this project indicate that systematically developed, self-paced instruction provides an effective means for orienting nontraditional college students and secondary students, especially minorities, to both engineering technology and basic materials science. In addition, students using such a system gain greater chances for mastering subject matter than with conventional modes of instruction.

Jacobs, J. A.↗
NASA NTRS1976

On the Age of Cosmic Rays as Derived from the Abundance of Be-10

The isotopic composition of cosmic ray Be, B, C, and N was studied using a new range versus total light technique. Special emphasis was placed on the Be isotopes and in particular, on the radioactive isotope Be-10 due to its mean lifetime against decay. The experiment consisted of a thin trigger scintillator, an acrylic plastic Cerenkov detector and a spark chamber, followed by a totally active stack of 14 scintillation detectors. This stack of scintillators made possible the measurement of range, and also permitted the removal of interacting events by continuously monitoring their identities along their trajectories. The experiment was carried by balloon to atmospheric depths ranging from 3.5 to 5.0 g sq cm residual atmosphere for a total exposure time of 23 hr. Results indicate the survival of ( 55 + or -21) % of the Be-10 in the arriving cosmic rays; the data were interpreted using the leaky box model of cosmic ray propagation.

Hagen, F. A.↗
NASA NTRS1975

The cosmic-ray age deduced from the Be-10 abundance

Satellite measurements of the radioactive cosmic-ray species Be-10 are reported. The abundance was measured near 100 MeV per nucleon with high-resolution solid-state telescopes on the IMP-7 and IMP-8 satellites during 1973 and 1974. These two independent measurements yield Be-10/Be ratios of less than 10 percent. Taken together with a galactic propagation model, these results show that the cosmic-ray 'clock' lifetime (most probable value of the order of 20 million years) is significantly greater than that deduced for a nominal interstellar gas density of the order of 1 to 3 atoms per cu cm.

Garcia-Munoz, M.↗
NASA NTRS1975

The seven ages of a planet

On the basis of almost universally held assumptions concerning the formation of the planets and the isolation of the solar system from outside influences it follows rather plausibly that all terrestrial planets pass in principle through seven stages. The processes involved include the solidification of grains from gas in the condensation stage, planetesimal interactions, and formation processes. Vigorous convection processes lead to the gravitational separation of iron and the outgassing of oceans. Other stages are related to plate tectonics and terminal volcanism. The ultimate stage of quiescence is characterized by a thick lithosphere and no volcanism.

Kaula, W. M.↗
NASA NTRS1976

Rb, Sr and strontium isotopic composition, K/Ar age and large ion lithophile trace element abundances in rocks and glasses from the Wanapitei Lake impact structure

Shock metamorphosed rocks and shock-produced melt glasses from the Wanapitei Lake impact structure have been examined petrographically and by electron microprobe. Eleven clasts exhibiting varying degrees of shock metamorphism and eight impact-produced glasses have been analyzed for Rb, Sr and Sr isotopic composition. Five clasts and one glass have also been analyzed for large ion lithophile (LIL) trace element abundances including Li, Rb, Sr, and Ba and the REE's. The impact event forming the Wanapitei Lake structure occurred 37 m.y. ago based on K/Ar dating of glass and glassy whole-rock samples. Rb/Sr isotopic dating failed to provide a meaningful whole-rock or internal isochron. The isotopic composition of the glasses can be explained by impact-produced mixing and melting of metasediments.

Winzer, S. R.↗
NASA NTRS1978

Space-age vacuum cleaning

Varied concepts for brushes and air handling remove dirt more effectively. Vacuum-cleaning techniques may be used in combination. Many of these concepts, while not appropriate for household cleaning, may find use in industry, research, and medicine.

Schneider, H. W.↗
NASA NTRS1977

Be-10 abundance and the age of cosmic rays - A balloon measurement

A balloon-borne payload was launched from Thompson, Canada, on August 15, 1973. The float depth averaged 4.5 g/sq cm of residual atmosphere, and the experiment live time was 31,500 sec. A total-energy-versus-range technique was used in the measurements. Preliminary results from this experiment have been given by Hagen et al. (1975). The final results are reported along with a detailed description of the analysis techniques. Information is provided concerning improved atmospheric and energy corrections, an updated estimation of the modulation effects, and a revised lifetime estimate.

Hagen, F. A.↗
NASA NTRS1976

The realities of recoil - Ar-39 recoil out of small grains and anomalous age patterns in Ar-39-Ar-40 dating

Excess Ar-39 in olivine from neutron-irradiated mixtures of olivine and K-rich glass was measured to determine the amount of Ar-39 transferred by recoil out of the glass and into the surrounding olivine grains. It was found that a total of 9.0% of the total Ar-39 recoiled out of the 3-micron glass grains and 2.45% out of the 15-micron glass grains. The mean depth of Ar-39 depletion of the surface of the glass grains was 0.1 micron.

Huneke, J. C.↗