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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 19 records
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Nuclear chemistry of returned lunar samples: Nuclide analysis by gamma-ray spectrometry

Concentrations of primordial radioelements and of cosmogenic radionuclides in crystalline rocks, breccias, and soils from the Ocean of Storms were determined. Concentrations of K, Th, U, Al-26, and Na-22 were determined for seven clastic or brecciated rocks, three sieved samples of fines, and one composite sample of sawdust from the cutting of a fragmental rock, all from samples obtained on the Apollo 14 mission. The K, Th, and U concentrations and cogmogenic radionuclide abundances in rocks and soils from Apollo 15 are also discussed.

Kelley, G. D.↗
NASA NTRS1975

Nuclear chemistry of returned lunar samples: Nuclide analysis by gamma-ray spectrometry

Primordial and cosmogenic radionuclide concentrations are determined nondestructively by gamma-ray spectrometry in soil and rock samples from the returned Apollo 17 sample collection from Taurus-Littrow and Descartes. Geochemical evidence in support of field geology speculation concerning layering of the subfloor basalt flows is demonstrated along with a possible correlation of magmatic fractionation of K/U as a function of depth. The pattern of radionuclide concentrations observed in these samples is distinct due to proton bombardment by the intense solar flares of August 4-9, 1972. Such radionuclide determinations are used in determining lunar sample orientation and characterizing solar flare activity.

Okelley, G. D.↗
NASA NTRS1988

Supernova neutrinos, neutral currents and the origin of fluorine

An argument is made for the existence of a significant role for neutrinos in the nuclear chemistry of an exploding supernova. Emphasis is given to the neutrino-induced nucleosynthesis of fluorine. It is shown that fluorine's solar abundance constrains the temperature of muon and tauon neutrinos to values near what is expected from the standard model.

Woosley, S. E.↗
NASA NTRS1973

Studies related to primitive chemistry. A proton and nitrogen-14 nuclear magnetic resonance amino acid and nucleic acid constituents and a and their possible relation to prebiotic

Preliminary proton nuclear magnetic resonance (NMR) studies were made to determine the applicability of this technique for the study of interactions between monomeric and polymeric amino acids with monomeric nucleic acid bases and nucleotides. Proton NMR results for aqueous solutions (D2O) demonstrated interactions between the bases cytosine and adenine and acidic and aromatic amino acids. Solutions of 5'-AMP admixed with amino acids exhibited more complex behavior but stacking between aromatic rings and destacking at high amino acids concentration was evident. The multisite nature of 5'-AMP was pointed out. Chemical shift changes for adenine and 5'-AMP with three water soluble polypeptides demonstrated that significant interactions exist. It was found that the linewidth-pH profile of each amino acid is unique. It is concluded that NMR techniques can give significant and quantitative data on the association of amino acid and nucleic acid constituents.

Manatt, S. L.↗
NASA NTRS2026

The Trajectory of Recent Solid State Fusion Results

Both NASA and Google have explored and funded Low Energy Nuclear Reaction (LENR) aka Solid-State Fusion or Lattice Confinement Fusion (LCF) research. NASA has funded efforts since 1989, and Google Research began in 2014. Google, and researchers initially-funded by Google, published significant scientific papers in Nature, Nature Communications and the Journal of Applied Physics. NASA began a significant set of LENR-triggering programs in 2012 resulting in papers in Physical Review C, the Journal of Electroanalytical Chemistry and the Journal of Condensed Matter Nuclear Science. Both NASA and Google engaged researchers across fields of nuclear physics, chemistry, electrochemistry, material science and more. NASA built upon early novel gas pumping experiments then followed the patented work of the US Navy SPAWAR (US8,419,919, “System and Method to Generate Particles”) and experiments with the Naval Surface Warfare Centers. Google supported researchers at Lawrence Berkeley National Laboratory (LBNL), the University of British Columbia (UBC), MIT and others. This resulted in patent applications and two granted patents (US10264661B2, “Target structure for enhanced electron screening” and US10566094B2 “Enhanced electron screening through plasmon oscillations”). These separate efforts, unknown to the researchers at the time, provided the impetus for the DoE ARPA-E LENR program followed by the DARPA DSO “Mechanisms for Amplification of Fusion Reaction Rates in Solids” (MARRS) program. This document briefly describes the overlapping NASA and Google Research efforts in plasma loading and electron screening emphasizing the results of the latest paper in Nature Communications. The papers and patents cited are listed.

electron screening↗
NASA NTRSDate not supplied

Knudsen Effusion Mass Spectrometry: Principles and Applications

Knudsen Effusion Mass Spectrometry (KEMS) is a well-established technique in physical chemistry. First, we discuss the basic principles of the technique. It is based on a small enclosure which sets up a condensed/vapor near equilibria. A small, well-defined orifice allows the vapor to be sampled a mass spectrometer. Although the number of groups utilizing this method has decrease significantly from its height in 1960s, we will show that it is still useful for many problems in physical chemistry, materials science, geology, and nuclear science. Specific examples illustrate its versatility: Measurement of the enthalpy of formation of HfO(g); measurement of activities in the Ti-Al-O and Ni-Al systems; measurement of activities in several rare earth silicate systems; measurement of vapor pressures above olivine; dating of minerals with K/Ar method; and determination of adsorption/desorption behavior on nuclear fission products on graphite. These are only a small sampling of the many applications of this versatile technique.

Mass spectrometry, thermodynamics, high temperatur↗
NASA NTRS1979

The challenge of detecting gravitational radiation is creating a new chapter in quantum electronics: Quantum nondemolition measurements

Future gravitational wave antennas will be approximately 100 kilogram cylinders, whose end-to-end vibrations must be measured so accurately (10 to the -19th power centimeters) that they behave quantum mechanically. Moreover, the vibration amplitude must be measured over and over again without perturbing it (quantum nondemolition measurement). This contrasts with quantum chemistry, quantum optics, or atomic, nuclear, and elementary particle physics where measurements are usually made on an ensemble of identical objects, and care is not given to whether any single object is perturbed or destroyed by the measurement. Electronic techniques required for quantum nondemolition measurements are described as well as the theory underlying them.

Braginsky, V. B.↗
NASA NTRS2021

Extreme Ozone Loss Following Nuclear War Results in Enhanced Surface Ultraviolet Radiation

For the first time, we use a modern climate model with interactive chemistry including the effects of aerosols on photolysis rates to simulate the consequences of regional and global scale nuclear wars (injecting 5 and 150 Tg of soot respectively) for the ozone layer and surface ultraviolet (UV) light. For a global nuclear war, heating in the stratosphere, reduced photolysis, and an increase in catalytic loss from the Hox cycle cause a 15 year-long reduction in the ozone column, with a peak loss of 75% globally and 65% in the tropics. This is larger than predictions from the 1980s, which assumed large injections of nitrogen oxides (NOx),but did not include the effects of smoke. NOx from the fireball and the fires provide a small (5%) Increase to the global average ozone loss for the first few years. Initially, soot would shield the surface from UV-B, but UV Index values would become extreme: greater than 35in the tropics for 4years, and greater than 45during the summer in the southern polar regions for 3 years. For a regional war, global column ozone would be reduced by 25% with recovery taking 12 years. This is similar to previous simulations, but with a faster recovery time due to a shorter lifetime for soot in our simulations. In-line photolysis provides process specific action spectra enabling future integration with biogeochemistry models and allows output that quantifies the potential health impacts from changes in surface UV for this and other larger aerosol injections.

nuclear war↗
NASA NTRS1987

Megawatt level electric propulsion perspectives

For long range space missions, deliverable payload fraction is an inverse exponential function of the propellant exhaust velocity or specific impulse of the propulsion system. The exhaust velocity of chemical systems are limited by their combustion chemistry and heat transfer to a few km/s. Nuclear rockets may achieve double this range, but are still heat transfer limited and ponderous to develop. Various electric propulsion systems can achieve exhaust velocities in the 10 km/s range, at considerably lower thrust densities, but require an external electrical power source. A general overview is provided of the currently available electric propulsion systems from the perspective of their characteristics as a terminal load for space nuclear systems. A summary of the available electric propulsion options is shown and generally characterized in the power vs. exhaust velocity plot. There are 3 general classes of electric thruster devices: neutral gas heaters, plasma devices, and space charge limited electrostatic or ion thrusters.

Jahn, Robert G.↗
NASA NTRS1976

Gas phase chemistry in comets

The significance of gas phase reactions in determining the nuclear structure of comets is discussed. The sublimation of parent molecules such as H2O, CH4, CO2, and NH3 from the surface of the nucleus and their subsequent photodissociation and ionization in forming observed cometary molecular species are elaborated.

Oppenheimer, M.↗
NASA NTRS2021

Physics and Chemistry of Te and HgTe-based Ternary Melts

Historically, the theoretical treatment of the liquid phases has always been more difficult and complicated than that for solid and gas phases. A liquid has no lattice structure as crystalline solids and the atoms/molecules in the liquid can migrate through it relatively rapidly. On the other hand, it is also interacting with many other atoms/molecules so that the simplifications of the kinetic theory of gases cannot be employed. For more complicated liquids, such as the liquids of high ionicity and those containing hydrogen bonds and electric dipoles, the understanding is far from complete. At the same time, accurate information on the physics and chemistry of semiconductor melts is needed for the quantitative descriptions of the process of crystal growth from melt. The pre-crystallization phenomena in the liquid phase are critical because the properties of the grown crystals depend on the state and structure of the melt as well as the thermal history of the melt during solidification process. However, the data on the liquid phase, such as thermophysical properties of semiconductor melts are scarce, especially for the HgTe-based II-VI ternary compound semiconductors because of their high vapor pressure and extreme toxicity. Analysis of the thermophysical properties of the melt can provide information about structural transitions of the melt during the solidification process. From a broader point of view, the structure of liquids is much more complicated than the crystalline solids, especially the relaxation behavior through different thermal histories. The theory of hetero-phase fluctuations of liquids is applicable to any many-body systems including condensed-matter physics, field theory, physics of nuclear-matter, cosmology, biology and even sociology. This book summarizes the physics and chemistry from the experimental measurements and theoretical analyses of phase diagram, thermodynamic properties, density, thermal conductivity, viscosity, and electrical conductivity on the binary, pseudo-binary and ternary melts of the most advanced IR-detector material systems of HgCdTe and HgZnTe as well as the analyses of these results. The main objectives of this study are: (1) to provide the phase diagrams and thermodynamic properties of Hg-Cd-Te and Hg-Zn-Te systems through quantitatively fitting the experimental data by assuming an associated solution model for the liquid phase, (2) to experimentally measure the thermophysical properties of the Hg-Cd-Te and Hg-Zn-Te melts, including density, viscosity, electrical conductivity and thermal conductivity as functions of temperature and composition and (3) to enhance the fundamental knowledge of hetero-phase fluctuations and relaxation phenomena in the melts and extend our understanding of the solidification process in order to interpret the experimental results of crystal growth so as to improve the melt growth processes of the compound semiconductor. The physics and chemistry of Te and HgTe-based ternary melts were explored through the studies of the structural transformation during melting, the supercooling during solidification, the relaxation phenomena after rapid cooling of the melts and the metal-semiconductor transition in the melts through the analyses of electrical conductivity and Lorenz number. An in-depth study on the thermophysical properties and their time-dependent structural dynamic processes taking place in the vicinity of the solid-liquid phase transition of the narrow homogeneity range HgTe-based ternary semiconductors as well as the analysis of the homogenization process in the melt will also be presented.

Thermophysical properties↗