SEARCH · Search NASA

Results for “DEUTERIUM”

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.

SourceResearch connectionFrom yearThrough year

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

At least 91 records · Page 5

All sources NASA NTRS DOE OSTI

NASA NTRS1972

Field emission energy distributions of hydrogen and deuterium on the /100/ and /110/ planes of tungsten.

Total energy distributions of field emitted electrons from the tungsten (110) and (100) planes as a function of coverage by hydrogen and deuterium have been recorded utilizing a spherical deflection energy analyzer. The elastic tunneling resonance spectrum gives a plot of the 'local density of states' in the adsorbate. The inelastic tunneling spectrum reveals those discrete excitation energies available in the adsorbate-substrate complex. These spectroscopic data have been used to infer the chemical nature of the binding states which have been observed in the flash desorption spectrum of hydrogen from tungsten.

Plummer, E. W.↗

NASA NTRS1973

Gas phase recombination of hydrogen and deuterium atoms

Rate constants for the reaction H + H + M - H2 + M, with M = H2, He, and Ar were measured over the temperature range 77 to 298 K. Hydrogen atoms were produced by thermal dissociation and absolute atom concentrations were measured through use of self-balancing, isothermal catalytic probe detector. The specific rate constants were 8.1 + or - 0.4 x 10 to the minus 33rd power, 7.0 + or - 0.4 x 10 to the minus 33rd power, and 9.2 + or - 0.6 x at 298 K for M = H2, He, and Ar respectively; these values rising to 18.5 + or - 2.2 x 10 to the minus 33rd power, 12.0 + or - 1.5 x 10 to the minus 33rd power, and 27.4 + or - 4.6 x 10 to the minus 33rd power cm to the 6th power/molecules sq/sec at 77 K. for the equivalent deuterium atom process with D2 as the third body, the rate constants are 6.1 + or - 0.3 x 10 to the minus 33rd power cm to the 6th power/molecules sq/sec at 298 K and 15.1 + or - 1.0 x 10 to the minus 33rd power cm to the 6th power/molecules sq/sec at 77 K. These values are compared with previous experimental measurements and with recent theoretical calculations.

Trainor, D. W.↗

NASA NTRS1972

Access to uncombined titanium through an inhibiting film in sublimation pumping of deuterium.

In principle, titanium bulk sublimator pumping should be ideal for removing large quantities of deuterium from a vacuum system. In practice, much of the deposited titanium remains uncombined and is wasted. We have demonstrated, through a series of experiments, that it is possible (by the addition of a thin layer of titanium to an apparently occluded surface) to gain access to previously deposited sublayers of uncombined titanium in spite of the presence of an inhibiting film (such as an oxide) on the surface.

Steinberg, R.↗

NASA NTRS1973

Deuterium in the early solar system.

An attempt is made to construct a self-consistent picture of the deuterium abundance in the early solar system based on the assumption of chemical equilibrium in the solar nebula. A recent determination of the D/H ratio for the atmosphere of Jupiter is consistent with a previous estimate of the D/H ratio for the protosun. The high (greater than .00015) D/H ratios determined from analyses of carbonaceous meteorites imply an equilibrium temperature less than 270 K, in marked disagreement with the equilibrium temperature determined for the same material by oxygen isotope cosmothermometry.

Black, D. C.↗

NASA NTRS1973

The deuterium puzzle in the symmetric universe

An attempt was made to use deuterium abundance in the symmetric universe to prove that no nucleosynthesis takes place during annihilation and therefore neutrons were loss before nucleosynthesis. Data cover nucleosynthesis during the radiative era, cross section estimates, maximum abundance of He-4 at the end of nucleosynthesis area, and loss rate.

Leroy, B.↗

NASA NTRS1977

Analysis of diffential absorption lidar technique for measurements of anhydrous hydrogen chloride from solid rocket motors using a deuterium fluoride laser

An active optical technique (differential absorption lidar (DIAL)) for detecting, ranging, and quantifying the concentration of anhydrous HCl contained in the ground cloud emitted by solid rocket motors (SRM) is evaluated. Results are presented of an experiment in which absorption coefficients of HCl were measured for several deuterium fluoride (DF) laser transitions demonstrating for the first time that a close overlap exists between the 2-1 P(3) vibrational transition of the DF laser and the 1-0 P(6) absorption line of HCl, with an absorption coefficient of 5.64 (atm-cm) to the -1 power. These measurements show that the DF laser can be an appropriate radiation source for detecting HCl in a DIAL technique. Development of a mathematical computer model to predict the sensitivity of DIAL for detecting anhydrous HCl in the ground cloud is outlined, and results that assume a commercially available DF laser as the radiation source are presented.

Bair, C. H.↗

NASA NTRS1978

On the deuterium-to-hydrogen ratio in the atmosphere of Uranus

Photoelectric observations and recently published laboratory measurements of HD imply an upper limit on the deuterium-to-hydrogen ratio in Uranus's atmosphere of D/H less than 9.6 x 10 to the -5th power. This is much closer to values currently being proposed for Jupiter

Trafton, L.↗

NASA NTRS1980

Deuterium in carbonaceous chondrites

Hydrogen isotopic compositions in seven carbonaceous chondrites lie in the range -70 to +771 per thousand relative to standard mean ocean water. These values decrease, to a range from -145 to +219 per thousand, after low-temperature oxidation in an oxygen plasma. Deuterium enrichment is therefore concentrated in the organic matter, the hydrous silicates probably lying close to the terrestrial range for such material. Calculated values for delta D of the organic fraction are +450 per thousand for Orgueil and Ivuna and up to +1600 per thousand for Renazzo. These enrichments, at least for Orgueil and Ivuna, suggest equilibration with protosolar hydrogen at very low temperatures. Assuming a value of 2.5 x 10 to the -5th for the protosolar D/H ratio, nominal equilibration temperatures of 230 K for silicates and 180 K for organic matter may be derived.

Kolodny, Y.↗

NASA NTRS1980

Water-deuterium oxide exchange in polymers used in spacecraft applications

The replacement of water (H2O) by deuterium oxide (D2O) and the exchange between atmospheric water and adsorbed or absorbed D2O were investigated for the polymeric materials Kapton and Mylar using thermal gravimetric analysis and infrared spectroscopy. Replacement of H2O by D2O is easily accomplished. However, exposure of D2O samples to the ambient atmosphere or gases containing H2O results in rapid proton and deuteron exchange between H2O vapor and adsorbed D2O. Replacement of H2O by D2O would not be a practical solution to alleviate spectral interferences that would result from water outgassing in spacecraft orbital environments. Maintaining the materials of interest in a dehydrated state is a more reasonable approach.

Carre, D. J.↗

NASA NTRS1980

Hydrogen fluoride and deuterium fluoride lasers. Citations from the International Aerospace Abstracts data base

Research cited from the international literature adresses various aspects of hydrogen fluoride and deuterium fluoride lasers. Topics covered include flows, laser outputs, molecular relaxation, molecular rotation, energy conversion efficiency, reaction kinetics, and laser materials. Continous wave and pulsed laser are considered. This updated bibliography contains 283 citations, 53 of which are new additions to the previous edition.

Mauk, S. C.↗

NASA NTRS1981

Ordered ground states of metallic hydrogen and deuterium

The physical attributes of some of the more physically distinct ordered states of metallic hydrogen and metallic deuterium at T = 0 and nearby are discussed. The likelihood of superconductivity in both is considered with respect to the usual coupling via the density fluctuations of the ions.

Ashcroft, N. W.↗

NASA NTRS1980

Theoretical predictions of deuterium abundances in the Jovian planets

Current concepts for the origin of the Jovian planets and current constraints on their interior structure are used to support the argument that the presence of large amounts of 'ice' (H2O, CH4, and NH3) in Uranus and Neptune indicates temperature low enough to condense these species at the time Uranus and Neptune formed. Such low temperatures, however, imply orders-of-magnitude fractionation effects for deuterium into the 'ice' component if isotopic equilibration can occur. The present models thus imply that Uranus and Neptune should have D/H ratio at least four times primordial, contrary to observation for Uranus. It is found that the Jovian and Saturnian D/H should be close to primordial regardless of formation scenario.

Hubbard, W. B.↗

NASA NTRS1983

Identification of deuterium ions in the ionosphere of Venus

The dominant mass two ion in the ionosphere of Venus is identified as D(+) through analysis of the height variation of (mass two ion)/(H(+)) measured in the chemical equilibrium region by the ion mass spectrometer on the Pioneer Venus Orbiter. This result leads to (D)/(H) = (2.2 + or - 0.6) x 10 to the -2 at the turbopause, which agrees with the ratio measured in the lower atmosphere by the large probe mass spectrometer. The 100-fold deuterium enrichment supports previous suggestions that Venus has lost at least 0.3 percent of a terrestrial ocean.

Hartle, R. E.↗

NASA NTRS1985

Results of a search for deuterium at 25-50 GC/c using a magnetic spectrometer

A method is presented for separately identifying isotopes using a Cerenkov detector and a magnet spectrometer. Simulations of the method are given for separating deuterium from protons. The simulations are compared with data gathered from the 1979 flight of the New Mexico State University balloonborne magnet spectrometer. The simulation and the data show the same general characteristics lending credence to the technique. The data show an apparent deuteron signal which is (11 + or - 3)% of the total sample in the rigidity region 38.5 to 50 GV/c. Until further background analysis and subtraction is performed this should be regarded as an upper limit to the deuteron/(deuteron+proton) ratio.

Golden, R. L.↗

NASA NTRS1984

Theory of the spin-1 bosonic liquid metal - Equilibrium properties of liquid metallic deuterium

The theory of a two-component quantum fluid comprised of spin-1/2 fermions and nonzero spin bosons is examined. This system is of interest because it embodies a possible quantum liquid metallic phase of highly compressed deuterium. Bose condensation is assumed present and the two cases of nuclear-spin-polarized and -unpolarized systems are considered. A significant feature in the unpolarized case is the presence of a nonmagnetic mode with quadratic dispersion owing its existence to nonzero boson spin. The physical character of this mode is examined in detail within a Bogoliubov approach. The specific heat, bulk modulus, spin susceptibility, and thermal expansion are all determined. Striking contrasts in the specific heats and thermal-expansion coefficients of the liquid and corresponding normal solid metallic phase are predicted.

Oliva, J.↗

NASA NTRS1985

Astration of cosmological deuterium

Attention is given to the degree of primordial deuterium's astration through the continuous galactic processes of star formation and chemical evolution. Exact analytic solutions are given for galactic chemical evolution when infall of constant composition occurs at a rate, f(t), which is presently defined. Solutions are given for the linear model with instantaneous recycling and with constant return fraction R. The results suggest that big bang D/H was at least three times larger than the largest values observed in today's solar neighborhood, and even larger if matter falling into the disk is already astrated.

Clayton, D. D.↗

NASA NTRS1985

Ultrahigh pressures - Optical observations and Raman measurements of hydrogen and deuterium to 1.47 Mbar

Hydrogen and deuterium have been pressurized under static conditions to 1.47 Mbar, which is higher by a factor of 2 than the static data of Sharma et al. (1980). Measurements of the vibron indicate an initial increase and then a sharp decrease in frequency at pressures above 0.5 Mbar. At 1.14 Mbar the vibron frequency decreased to the zero-pressure value, and at 1.47 Mbar the frequency of the vibron in hydrogen is 90/cm below the value of the vibrational mode of the isolated molecule. This pronounced softening of the vibron suggests strengthened intermolecular interaction.

Mao, H. K.↗

NASA NTRS1985

Deuterium on Venus - Model comparisons with Pioneer Venus observations of the predawn bulge ionosphere

A self-consistent model of the Venus ionosphere in the predawn bulge region where the mass-two ion density is observed to be maximum was prepared in order to examine the question of mass-two ion identification in detail. The model calculations are compared to the Pioneer Venus observations of ion composition and structure in the 153-250 km altitude range. The observed densities of major ions O2(+) and O(+) are used to constrain the source of ionization. Once the source is determined, the density distribution of D(+) and H2(+) is calculated for various values of D and H2 in the atmosphere. It is found that mass-two ion is clearly due to deuterium and that the H2 contribution to the mass-two ion is small, if present at all.

Kumar, S.↗