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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 NTRS1975

Hydrogen interactions with metals

Review of the literature on the nature and extent of hydrogen interactions with metals and the role of hydrogen in metal failure. The classification of hydrogen-containing systems is discussed, including such categories as covalent hydrides, volatile hydrides, polymeric hydrides, and transition metal hydride complexes. The use of electronegativity as a correlating parameter in determining hydride type is evaluated. A detailed study is made of the thermodynamics of metal-hydrogen systems, touching upon such aspects as hydrogen solubility, the positions occupied by hydrogen atoms within the solvent metal lattice, the derivation of thermodynamic functions of solid solutions from solubility data, and the construction of statistical models for hydrogen-metal solutions. A number of theories of hydrogen-metal bonding are reviewed, including the rigid-band model, the screened-proton model, and an approach employing the augmented plane wave method to solve the one-electron energy band problem. Finally, the mechanism of hydrogen embrittlement is investigated on the basis of literature data concerning stress effects and the kinetics of hydrogen transport to critical sites.

Mclellan, R. B.↗
NASA NTRS1993

Investigation of lunar base thermal control system options

Long duration human exploration missions to the Moon will require active thermal control systems which have not previously been used in space. The two technologies which are most promising for long term lunar base thermal control are heat pumps and radiator shades. Recent trade-off studies at the Johnson Space Center have focused development efforts on the most promising heat pump and radiator shade technologies. Since these technologies are in the early stages of development and many parameters used in the study are not well defined, a parametric study was done to test the sensitivity to each assumption. The primary comparison factor in these studies was the total mass system, with power requirements included in the form of a mass penalty for power. Heat pump technologies considered were thermally driven heat pumps such as metal hydride, complex compound, absorption and zeolite. Also considered were electrically driven Stirling and vapor compression heat pumps. Radiator shade concepts considered included step shaped, V-shaped and parabolic (or catenary) shades and ground covers. A further trade study compared the masses of heat pump and radiator shade systems.

Ewart, Michael K.↗
NASA NTRS2012

Method and apparatus for hydrogen production from water

A method, apparatuses and chemical compositions are provided for producing high purity hydrogen from water. Metals or alloys capable of reacting with water and producing hydrogen in aqueous solutions at ambient conditions are reacted with one or more inorganic hydrides capable of releasing hydrogen in aqueous solutions at ambient conditions, one or more transition metal compounds are used to catalyze the reaction and, optionally, one or more alkali metal-based compounds. The metal or alloy is preferably aluminum. The inorganic hydride is from a family of complex inorganic hydrides; most preferably, NaBH.sub.4. The transition metal catalyst is from the groups VIII and IB; preferably, Cu and Fe. The alkali metal-based compounds are preferably NaOH, KOH, and the like. Hydrogen generated has a purity of at least 99.99 vol. % (dry basis), and is used without further purification in all types of fuel cells, including the polymer electrolyte membrane (PEM) fuel cell.

Muradov, Nazim Z.↗
NASA NTRS1978

A resonant state and the ground state of positronium hydride

The lowest-lying resonance occurring in S-wave positronium-hydrogen scattering is reinvestigated, using the complex-rotation method. By employing a generalized Hylleraas-type wave function that includes all six interparticle coordinates, a very accurate value of the resonance position is obtained, along with a good value of the width. The present result for the resonance position (-1.205 plus or minus 0.001 Ry) is lower than the previous result of Drachman and Houston, who omitted the interelectronic coordinate in their trial function. In addition, the lowest ground-state energy of positronium hydride is obtained by using 210 terms in the trial wave function. The effect of the interelectronic coordinate and others on both the resonant energy and the binding energy of PsH is discussed.

Ho, Y. K.↗
NASA NTRS2001

Resonances in Positronium Hydride

Recently, Ho and his colleagues have calculated the positions and widths of a series of resonances in the Ps+H scattering system, using the complex -rotation method and have compared them with estimates that I made many years ago using a quite different technique. I assumed that the resonance mechanism was the existence in the rearrangement channel [e+ + H-] of an infinite series of perturbed Coulomb bound states. Although these must be broadened and shifted by coupling with the open scattering channel, I expected them to lie very close to the actual resonance positions. To verify this, I did a model calculation for S-waves, including the coupling, and found that the first two resonances were not shifted very far from their unperturbed position. The new, detailed calculation agrees with this result, but when the P-wave was examined it was found, surprisingly, that the lowest resonance indeed moved up in energy by a large amount. With the help of Joseph DiRienzi of the College of Notre Dame of Maryland I am now extending the old calculation to P- and D-waves, in an attempt to understand this unexpected energy shift. Results will be presented at the Workshop.

Drachman, Richard J.↗
NASA NTRS1984

The significance of far-infrared spectra of the interstellar medium

This paper deals with the analysis of interstellar clouds through infrared and submillimeter observations. The determination of temperature, density, state of ionization and abundance of different chemical constituents is discussed for clouds exhibiting a range of optical depths. There is a preferred choice of spectral features useful for examining different types of gaseous complexes. The prospects for improving the understanding of chemical reaction schemes in interstellar clouds are outlined. Prime advances may be expected in improved data on the abundance of atoms; diatomic hydrides; other small, hydrogen-containing molecules; and their ions.

Harwit, M.↗
NASA NTRSDate not supplied

Aluminum Borohydride Ammines as Fuels for Hybrid Rocket Motors: Theoretical Performance and Particle Synthesis

The aluminum borohydride ammines, Al(BH4)3·XNH3, are a family of complexes between aluminum borohydride and ammonia for which up to six moles of ammonia can be complexed per mole of aluminum borohydride. Two of these complexes, the diammine (X = 2) and hexammine (X = 6) are of particular interest for use in hybrid rocket motors as additives and stand alone fuels. This study compares these compounds against other metal hydride for their potential as additives to increase the regression rate of solid fuel grains. The theoretical performance of the diammine as a stand alone fuel paired with non-toxic oxidizers is also investigated. The low temperature and good performance of these combinations make them of interest for low cost orbital maneuvering thrusters. Finally, the synthesis process for Al(BH4)3·6NH3 is discussed and TGA/DSC results are presented.

hybrid rockets↗
NASA NTRSDate not supplied

Aluminum borohydride ammines as fuels for hybrid rocket motors: theoretical performance and particle synthesis

The aluminum borohydride ammines, Al(BH4)3·XNH3, are a family of complexes between aluminum borohydride and ammonia for which up to six moles of ammonia can be complexed per mole of aluminum borohydride. Two of these complexes, the diammine (X = 2) and hexammine (X = 6) are of particular interest for use in hybrid rocket motors as particle additives and stand alone fuels. This study compares these compounds against other metal hydrides for their potential to increase the regression rate of solid fuel grains. The theoretical performance of the diammine as a stand alone fuel paired with non-toxic oxidizers is also investigated. The low temperature and good performance of these combinations make them of interest for low cost orbital maneuvering thrusters. Finally, results on the synthesis of Al(BH4)3·6NH3 and its thermal characterization are presented.

hybrid rockets↗
NASA NTRS2001

Resonances in Positronium Hydride

We re-examine the problem of calculating the positions and widths of the lowest-lying resonances in the Ps + H scattering system which consists of two electrons, one positron and one proton. The first of these resonances, for L=0, was found by the methods of complex rotation and stabilization, and later described as a Feshbach resonance lying close to a bound state in the closed-channel e (+) + H (-) system. Recently, results for the L=1 and 2 scattering states were published, and it was found, surprisingly, that there is a larae shift in the positions of these resonances. In this work we repeat the analysis for L=1 and find an unexpected explanation for the shift.

DiRienzi, Joseph↗
NASA NTRS1995

NASA Tech Briefs, November 1995

The contents include: 1) Mission Accomplished; 2) Resource Report: Marshall Space Flight Center; 3) NASA 1995 Software of the Year Award; 4) Microbolometers Based on Epitaxial YBa2Cu3O(sub 7-x) Thin Films; 5) Garnet Random-Access Memory; 6) Fabrication of SNS Weak Links on SOS Substrates; 7) High-Voltage MOSFET Switching Circuit; 8) Asymmetric Switching for a PWM H-Bridge Power Circuit; 9) Better Ohmic Contacts for InP Semiconductor Devices; 10) Low-Bandgap Thermovoltaic Materials and Devices; 11) Digital Frequency-Differencing Circuit; 12) Imaging Magnetometer; 13) Computer-Assisted Monitoring of a Complex System; 14) Buffered Telemetry Demodulator; 15) Compact Multifunction Inspection Head; 16) Optical Detection of Fractures in Ceramic Diaphragms; 17) Eddy-Current Detection of Cracks in Reinforced Carbon/Carbon; 18) Apparent Thermal Conductivity of Multilayer Insulation; 19) Optimizing Misch-Metal Compositions in Metal Hydride Anodes; 20) Device for Sampling Surface Contamination; 21) Probabilistic Failure Assessment for Fatigue; 22) Probabilistic Fatigue and Flaw-Propagation Analysis; 23) Windows Program for Driving the TDU-850 Printer; 24) Subband/Transform MATLAB Functions for Processing Images; 25) Computing Equilibrium Chemical Compositions; 26) Program Processes Thermocouple Readings; 27) ICAN-Second-Generation Integrated Composite Analyzer; 28) Integrated Composite Analyzer with Damping Capabilities; 29) Computing Efficiency of Transfer of Microwave Power; 30) Program Calculates Power Demands of Electronic Designs; 31) Cost-Estimation Program; 32) Program Estimates Areas Required by Electronic Designs; 33) Program to Balance Mapped Turbopump Assemblies; 34) BiblioTech; 35) Controlling Mirror Tilt With a Bimorph Actuator; 36) Burst-Disk Device Simulates Effect of Pyrotechnic Device; 37) Bearing-Mounting Concept Accommodates Thermal Expansion; 38) Parallel-Plate Acoustic Absorbers for Hot Environments; 39) Adjustable-Length Strut Withstands Large Cyclic Loads; 40) Tool Indicates Contact Angles in Bearing Raceways; 41) Gravity Slides With Magnetic Braking; 42) High-Torque, Lightweight, Pneumatically Driven Wrench for Small Spaces; 43) Device for Testing Compatibility of an O-Ring; 44) Magnetic Heat Pump Containing Flow Diverters; 45) Variable-Tilt Helicopter Rotor Mast; 46) "Beach-Ball" Robotic Rovers; 47) Apparatus Would Measure Temperatures of Ball Bearings; 48) Flexible Borescope for Inspecting Ducts; 49) Texturing Copper To Reduce Secondary Emission of Electrons; 50) Automated Laser Cutting in Three Dimensions; 51) Algorithm Helps Monitor Engine Operation; 52) Flexible Revision of Data-Processing Communications; 53) Software for Managing the Use of Land; 54) Thermal Strap Increases Cryocooling Efficiency; 55) Reversible Nut With Engagement Indication; 56) Control Algorithms for Kinematically Redundant Manipulators; 57) Computed Hydrogen-Flow Splits in a Rocket Engine; 58) Pressure and Thermal Modeling of Rocket Launches; 59) Field of View of a Spacecraft Antenna: Analysis and Software; 60) Digital Controller for Laser-Beam-Steering Subsystem; 61) More About Beam-Steering Subsystem for Laser Communication; 62) Digital Controller for Laser-Beam-Steering Subsystem: Part 2; 63) Interface Circuit Board for Space-Shuttle Communications; 64) Automated Planning of Spacecraft Telecommunications; 65) Artifacts of Spectral Analysis of Instrument Readings; 66) Neural-Network Controller for Vibration Suppression; 67) Adaptive Finite-Element Computation in Fracture Mechanics; 68) Attitude Control for the Cassini Spacecraft; 69) Analytical Model for Fluid Dynamics in a Microgravity Environment; 70) Study of Rocket-Engine Joints Bonded by NVCU/NARloy-Z; 71) Improved Silicon Nitride for Advanced Heat Engines; 72) Parameters for Welding Aluminum/Lithium Alloys; 73) Lightweight Composite Intertank Structure; 74) Foil Patches Seal Small Vacuum Leaks; 75) Data Base on Cables and Connectors; 76) Effect of Clock Mode on Radiation Hardnessf an ADC; and 77) Fault-Tolerant Control for a Robotic Inspection System.

Source record↗
NASA NTRS1994

Structure and stability of hydrous minerals at high pressure

The presence of even small amounts of hydrogen in the Earth's deep interior may have profound effects on mantle melting, rheology, and electrical conductivity. The recent discovery of a large class of high-pressure H-bearing silicates further underscores the potentially important role for hydrous minerals in the Earth's mantle. Hydrogen may also be a significant component of the Earth's core, as has been recently documented by studies of iron hydride at high pressure. In this study, we explore the role of H in crystal structures at high pressure through detailed Raman spectroscopic and x ray diffraction studies of hydrous minerals compressed in diamond anvil cells. Brucite, Mg(OH)2, has a simple structure and serves as an analogue for the more complex hydrous silicates. Over the past five years, this material has been studied at high pressure using shock-compression, powder x ray diffraction, infrared spectroscopy, Raman spectroscopy, and neutron diffraction. In addition, we have recently carried out single-crystal synchrotron x-ray diffraction on Mg(OH)2 and Raman spectroscopy on Mg(OD)2 at elevated pressure. From all these studies, an interesting picture of the crystal chemical behavior of this material at high pressure is beginning to emerge. Some of the primary conclusions are as follows: First, hydrogen bonding is enhanced by the application of pressure. Second, layered minerals which are elastically anisotropic at low pressure may not be so at high pressure. Furthermore, the brucite data place constraints on the effect of hydrogen on seismic velocities and density at very high pressure. Third, the stability of hydrous minerals may be enhanced at high P by subtle structural rearrangements that are difficult to detect using traditional probes and require detailed spectroscopic analyses. Finally, brucite appears to be unique in that it undergoes pressure-induced disordering that is confined solely to the H-containing layers of the structure.

Duffy, T. S.↗
NASA NTRS1975

Positronium-hydrogen elastic scattering

Elastic scattering of positronium atoms by hydrogen atoms below the excitation threshold at 5.1 eV is investigated with the investigation limited to the spin-zero (singlet) state of the two electrons. Nonresonant S-wave phase shifts have been obtained from normalizable trial functions by extracting the center-of-mass wave function and examining its spatial behavior. An effective-range expansion is fitted to the phase shifts and the previously obtained positronium-hydride bound-state energy to yield a scattering length approximately equal to 5.3 Bohr radii as compared with Fraser's (1961) corrected exchange result of 7.28 Bohr radii. The stabilization method suggests that a resonance occurs at a scattering energy of 4.5 eV, about 0.6 eV below the excitation threshold. Using the complex-rotation method, evidence is obtained which confirms the existence of the resonance, and its width is estimated to be about 0.06 eV.

Drachman, R. J.↗
NASA NTRS1972

A discussion of CO and O on Venus and Mars

The absorption of solar ultraviolet radiation in the wavelength range 2000 to 2200 A by CO2 strongly reduces the dissociation rate of HCl on Venus. The Cl catalytic reaction for the rapid recombination of O and CO and the yellow coloration of the Venus haze by OCl(-) and Cl3(-) appears to be unlikely. At the time of the Martian dust storm, the dissociation of H2O in the vicinity of the surface may vanish. The increase of dissociation at high altitudes, however, can be the source of H atoms in the upper atmosphere. The H atoms from the dissociation of hydrides may catalyze the recombination of CO and O in the lower atmospheres of these planets according to the following scheme: H + CO + M yields HCO + M, and HCO + O yields H + CO2. In the case of Venus, there may be other kinds of sinks for the photodissociation products, and its chemical environment might be more complex than that of Mars.

Shimizu, M.↗
NASA NTRS2006

Experimental Evaluation of a Water Shield for a Surface Power Reactor

As part of the Vision for Space Exploration the end of the next decade will bring man back to the surface of the moon. One of the most critical issues for the establishment of human presence on the moon will be the availability of compact power sources. The establishment of man on the moon will require power from greater than 10's of kWt's in follow on years. Nuclear reactors are extremely we11 suited to meet the needs for power generation on the lunar or Martian surface. reactor system. Several competing concepts exist for lightweight, safe, robust shielding systems such as a water shield, lithium hydride (LiH), Boron Carbide, and others. Water offers several potential advantages, including reduced cost, reduced technical risk, and reduced mass. Water has not typically been considered for space reactor applications because of the need for gravity to remove the potential for radiation streaming paths. The water shield concept relies on predictions of passive circulation of the shield water by natural convection to adequately cool the shield. This prediction needs to be experimentally evaluated, especially for shields with complex geometries. MSFC has developed the experience and fac necessary to do this evaluation in the Early Flight Fission - Test Facility (EFF-TF).

Pearson, J. Boise↗
NASA NTRS2007

Preliminary Evaluation of Convective Heat Transfer in a Water Shield for a Surface Power Reactor

As part of the Vision for Space Exploration, the end of the next decade will bring man back to the surface of the moon. A crucial issue for the establishment of human presence on the moon will be the availability of compact power sources. This presence could require greater than 10's of kWt's in follow on years. Nuclear reactors are well suited to meet the needs for power generation on the lunar or Martian surface. Radiation shielding is a key component of any surface power reactor system. Several competing concepts exist for lightweight, safe, robust shielding systems such as a water shield, lithium hydride (LiH), and boron carbide. Water offers several potential advantages, including reduced cost, reduced technical risk, and reduced mass. Water has not typically been considered for space reactor applications because of the need for gravity to fix the location of any vapor that could form radiation streaming paths. The water shield concept relies on the predictions of passive circulation of the shield water by natural convection to adequately cool the shield. This prediction needs to be experimentally evaluated, especially for shields with complex geometries. NASA Marshall Space Flight Center has developed the experience and facilities necessary to do this evaluation in its Early Flight Fission - Test Facility (EFF-TF).

Pearson J. Boise↗
NASA NTRS2002

D-Wave Resonances in Positronium Hydride

The problem of calculating the position and width of the lowest-lying (L = 0, 1) resonances in the Ps + H scattering system has recently been re-examined by the authors [1]. In the model used, resonances axe assumed generated by bound Rydberg states in the closed re-arranged channel [e(+) + H(-)]. This infinite series of Coulomb bound states are shifted somewhat by the coupling with the open scattering channel [Ps + H]. Estimates using this approach, first carried out by one of the authors [2] using a simple form of scattering wavefunction, indicated an anticipated small shift of resonance away from the Rydberg energy in the S-wave (L = 0). More recent results by Ho and Yan [3] using the complex-rotation method showed unexpected significant shifting in the P (L = 1) and D (L = 2)-wave resonance energies from their respective unperturbed values. Our re-calculation of the resonances [I I for L = 0 and I indicates that, in each case, reasonably consistent resonance energies are obtained by coupling the two lowest lying states (IS and 2S for L = 0 and 2P and 3P for L = 1). For each L it is the higher state (2S and 3P, respectively) that produces the resonance. The lower state (1S and 2P, respectively) is effective only in increasing the non-resonant phase shift. In this work we extend the model to L = 2 (D-waves). Our results show that, unlike the S and P-waves, the 313-state alone produces a resonant energy that is very close to the result of Yan and Ho [3]. Inclusion of the 4D-state produces a second resonance in the scattering system shifted up slightly from its unperturbed Rydberg energy.

Drachman, Richard J.↗
NASA NTRSDate not supplied

Affordable Development Strategy for NEP Nuclear Systems

One nuclear electric propulsion (NEP) reactor systems under consideration is a hydride moderated thermal spectrum reactor fueled by high assay low enriched uranium (HALEU). While such a reactor is expected to yield the lightest HALEU reactor design, its development challenges grow exponentially with increasing mission demands, most notably power output, specific weight of the overall system (which may require operation at temperatures exceeding 1200 K), service lifetime, and human-rated reliability. Two of the greatest cost drivers are full-powered nuclear demonstrations and extensive material development campaigns, so it is important to consider options that can minimize the need for or complexity of such tasks. This paper discusses a structured framework being developed for assessing how NEP design choices, such as materials selection, neutronic features, and heat-removal technologies, can translate into project risk and how project performance goals can be traded with development cost.Reactors operating at high temperatures often require cutting-edge heat transfer technologies and creep-resistant materials. Use of new materials in high temperature reactors brings additional complication beyond those common to any new space materials development campaign. For example, such materials may not possess necessary neutronic cross-sectional or neutronic irradiation data. Similarly, use of new materials may significantly influence core neutronics; in some extreme cases, neutronic reactivity feed-back of certain new materials can vary during their service life as radiation damage impacts the scattering cross-section. In an affordable development approach, high fidelity modeling and simulation tools are used to identify and characterize potential ‘knees-in-the-curves’ in the relationship that exists between the mission characteristics and the project risk. Of particular significance is use of modern uncertainty management and variance reduction methods to perform gap analyses that feed into phenomena identification and ranking tables (PIRT) commonly used to communicate nuclear readiness levels. Model-based measurements techniques are used to design sub-scale experiments as a substitute to minimize orcompletely eliminate the need for nuclear demonstrations.This paper will describe the approach and present preliminary results. It will lay the groundwork for developing a set of metrics that can be broadly characterized as system nuclear readiness levels and advancement degree of difficulty for nuclear systems. Equally importantly, a goal of this paper is to initiate a dialogue among stakeholders on what is the sufficient level of maturity that is required for launching a demonstration unit.

Dasari V Rao↗
NASA NTRS1976

Interstellar molecules

Progress in the discovery and study of interstellar molecules is summarized. The 36 molecular species thus far identified in interstellar space are listed in several groups which include simple hydrides, oxides, and sulfides, various derivatives of ammonia, molecules involving linear carbon chains, cyanides, and molecules related in structure to formaldehyde, alcohols, or ethers. Several free radicals are described, the discovery of molecules in external galaxies is discussed, and possible mechanisms for molecular formation are noted. Methods for examining relative isotopic abundances by measuring molecules in interstellar clouds are outlined, mechanisms for the excitation of interstellar molecules are reviewed, and values are presented for the C-12/C-13 abundance ratio in a number of interstellar clouds. The detection of interstellar masers is discussed along with pumping mechanisms and masing transitions in H2CO, CH, OH, and SiO. The nature of dense interstellar clouds is examined in terms of several simple and complex cloud models, with emphasis on multiple condensation models.

Townes, C. H.↗