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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 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

Decay rate of the second radiation belt

Variations in the Earth's trapped (Van Allen) belts produced by solar flare particle events are not well understood. Few observations of increases in particle populations have been reported. This is particularly true for effects in low Earth orbit, where manned spaceflights are conducted. This paper reports the existence of a second proton belt and it's subsequent decay as measured by a tissue-equivalent proportional counter and a particle spectrometer on five Space Shuttle flights covering an eighteen-month period. The creation of this second belt is attributed to the injection of particles from a solar particle event which occurred at 2246 UT, March 22, 1991. Comparisons with observations onboard the Russian Mir space station and other unmanned satellites are made. Shuttle measurements and data from other spacecraft are used to determine that the e-folding time of the peak of the second proton belt. It was ten months. Proton populations in the second belt returned to values of quiescent times within eighteen months. The increase in absorbed dose attributed to protons in the second belt was approximately 20%. Passive dosimeter measurements were in good agreement with this value.

Badhwar, G. D.↗
NASA NTRS2002

Ring Current Ion Coupling with Electromagnetic Ion Cyclotron Waves

A new ring current global model has been developed that couples the system of two kinetic equations: one equation describes the ring current (RC) ion dynamic, and another equation describes wave evolution of electromagnetic ion cyclotron waves (EMIC). The coupled model is able to simulate, for the first time self-consistently calculated RC ion kinetic and evolution of EMIC waves that propagate along geomagnetic field lines and reflect from the ionosphere. Ionospheric properties affect the reflection index through the integral Pedersen and Hall conductivities. The structure and dynamics of the ring current proton precipitating flux regions, intensities of EMIC global RC energy balance, and some other parameters will be studied in detail for the selected geomagnetic storms.

Khazanov. G. V.↗
NASA NTRS1976

A statistical study of the upstream wave boundary outside the earth's bow shock

The location of the forward boundary of the upstream wave region ahead of the earth's bow shock is investigated statistically using plasma and magnetic-field data obtained by Heos 1. The analysis is conducted on the assumption that the waves are produced by protons reflected from the bow shock and traveling upstream with an effective velocity equal to the product of a parameter, p, and the solar-wind bulk velocity. The data-reduction methods are summarized, and uncertainties in the determination of the value of p are discussed. It is found that the overall average boundary corresponds to a velocity of approximately twice the solar-wind velocity for protons reflected from the daytime sector of the bow shock. More refined analysis of the data shows that the value of p is approximately 1.6 near the subsolar point and greater than 2 along the daytime flanks of the bow shock.

Diodato, L.↗
NASA NTRS1984

Carbon-13 and proton nuclear magnetic resonance analysis of shale-derived refinery products and jet fuels and of experimental referee broadened-specification jet fuels

A proton and carbon-13 nuclear magnetic resonance (NMR) study was conducted of Ashland shale oil refinery products, experimental referee broadened-specification jet fuels, and of related isoprenoid model compounds. Supercritical fluid chromatography techniques using carbon dioxide were developed on a preparative scale, so that samples could be quantitatively separated into saturates and aromatic fractions for study by NMR. An optimized average parameter treatment was developed, and the NMR results were analyzed in terms of the resulting average parameters; formulation of model mixtures was demonstrated. Application of novel spectroscopic techniques to fuel samples was investigated.

Dalling, D. K.↗
NASA NTRS1985

A simple model for the formation of 'reflected', 'intermediate', and 'diffuse' ion distributions upstream of earth's bow shock

Detailed energetic ion and low-frequency wave experiments on ISEE 1, 2, and 3, have established correlations between the types of ion populations and waves observed to exist in the earth's foreshock region. The present calculation has the objective to quantitatively test the picture obtained for the earth's foreshock region. An analysis is conducted of the coupled spatial and temporal evolution of upstream protons and hydromagnetic waves by means of a simple model in which the protons are represented by counterstreaming beams which resonate with hydromagnetic waves, exciting the outward propagating modes and damping the inward propagating modes at a single wave number.

Lee, M. A.↗
NASA NTRS2020

Analysis of a 100-W Regenerative Fuel Cell Demonstration

A 100-W regenerative fuel cell (RFC) demonstration was successfully completed at the NASA Glenn Research Center on December 11, 2014. This effort was funded by Advanced Space Power Systems milestone and represented the first demonstration of passive laboratory-scale stacks arranged as an RFC, consisting of a non-flow-through fuel cell and a static-feed electrolyzer. Once developed, these stacks present the potential to minimize system mass, volume, and parasitic power in comparison to existing terrestrial electrochemical systems and nonnuclear power generation options. Testing involved the fuel cell powering a simulated load then recycling fuel cell product water by subsequently electrolyzing it to regenerate hydrogen and oxygen gases for fuel cell operations. A total of five cycles were completed over a 2-week period, yielding cell voltage data for stack performance and quality measures for regenerated reactants. Overall, round-trip efficiency was calculated to be 47.4 percent. Gas crossover was observed in electrolyzer gas products, as residual gas analysis showed 1.1 percent hydrogen in oxygen and 0.4 percent oxygen in hydrogen. Fuel cell product water was determined to be more acidic and conductive and have a higher fluoride content when compared to deionized water.

fuel cell↗
NASA NTRS2016

Re-Thinking the Use of the OML Model in Electric-Sail Development

The Orbit Motion Limited (OML) model commonly forms the basis for calculations made to determine the effect of the long, biased wires of an Electric Sail on solar wind protons and electrons (which determines the thrust generated and the required operating power). A new analysis of the results of previously conducted ground-based experimental studies of spacecraft-space plasma interactions indicate that the expected thrust created by deflected solar wind protons and the current of collected solar wind electrons could be considerably higher than the OML model would suggest. Herein the experimental analysis will be summarized and the assumptions and approximations required to derive the OML equation-and the limitations they impose-will be considered.

Stone, Nobie H.↗
NASA NTRS1986

Viscosity and the Chew-Goldberger-Low equations in the solar corona

A general discussion of the dominant terms in the stress tensor in a magnetized plasma such as the solar corona is presented. The importance of dissipative terms such as electrical resistivity, heat conduction, and interspecies collisions is assessed. For average coronal conditions, the proton stress tensor is found to reduce to the dominant terms in the classical expression for the viscous stress. The classical expression can fail in the transition region, however. In the diffusion region of reconnection, classical viscosity will be appropriate if the resistivity is very large, so that the diffusion region is broad, but in that case the viscous heating is small compared to the resistive heating. On the other hand, the more general expression for the stress tensor is required if the diffusion region is thin; the stress tensor will be important in this case. The electron stress tensor is also considered, and it is shown how the classical expression for electron viscosity can fail in the transition region and lower corona.

Hollweg, J. V.↗
NASA NTRS1992

Experimental studies of the far-infrared spectra of cosmic-type ices

Work performed during the period is reported. The abstract of a paper presented at the Second International Workshop on the Nature of Cometary Organic Matter is included. Far infrared spectra of amorphous and crystalline water ice before and after proton irradiation is presented. Also, a study of clathrate hydrates was conducted in which a methanol (CH3OH) clathrate hydrate was prepared and its far-infrared spectrum investigated. This paper is also included.

Hudson, Reggie L.↗
NASA NTRS2016

Electromagnetic Cyclotron Waves in the Solar Wind: Wind Observation and Wave Dispersion Analysis

Wind observed long-lasting electromagnetic cyclotron waves near the proton cyclotron frequency on 11 March 2005, in the descending part of a fast wind stream. Bi-Maxwellian velocity distributions are fitted for core protons, beam protons, and alpha-particles. Using the fitted plasma parameters we conduct kinetic linear dispersion analysis and find ion cyclotron and/or firehose instabilities grow in six of 10 wave intervals. After Doppler shift, some of the waves have frequency and polarization consistent with observation, thus may be correspondence to the cyclotron waves observed.

cyclotron↗
NASA NTRS1982

The proton concentration in the vicinity of the Io plasma torus

Observations of lightning-generated whistlers conducted with the aid of the Voyager 1 plasma wave instrument during the March, 1979 encounter of Jupiter have been employed in numerous studies involving Jupiters's inner magnetosphere. In an investigation carried out by Tokar et al. (1982), the Voyager whistler observations were combined with heavy ion charged particle measurements in the Io torus to determine the light ion charge concentration along the whistler propagation paths. In the investigation, simple models were used for the plasma distribution along the propagation paths. In the present study, an improved model is used for the plasma distribution in the inner magnetosphere. The adopted model treats a plasma in diffusive equilibrium under the action of gravitational, centrifugal, and ambipolar electric field forces.

Tokar, R. L.↗
NASA NTRS2020

Laboratory Studies of Astronomical Ices: Reaction Chemistry and Spectroscopy

In this article, we will describe the work of the Cosmic Ice Laboratory at NASA’s Goddard Space Flight Center to characterize the composition of and to understand the chemistry occurring in icy bodies in the Solar System and beyond. Our work has touched on a wide range of extraterrestrial environments including icy interstellar grains, small bodies such as comets and asteroids, and planets and moons. We are especially interested in the chemical and physical changes that occur in ices as a result of thermal changes or exposure to radiation. To this end, we conduct experiments designed to simulate cold extraterrestrial environments and measure physical properties of single- and multi-component ices. We expose ices to radiation (e.g., MeV protons or keV-MeV electrons) or high-energy photons (e.g., UV) to initiate physical and chemical changes. We conduct experiments using cryo-vacuum chambers equipped with analytical tools and radiation sources to make most of our measurements, including the collection of all spectroscopic data,in situ. When possible and appropriate, we also collect reaction products for further ex situ analysis. The work of the Cosmic Ice Lab provides critical data to astrochemists and others seeking to understand observations, make predictions, and plan future space missions.

Christopher K Materese↗
NASA NTRS2004

Ionic Liquids and New Proton Exchange Membranes for Fuel Cells

There is currently a great surge of activity in fuel cell research as laboratories across the world seek to take advantage of the high energy capacity provided by &el cells relative to those of other portable electrochemical power systems. Much of this activity is aimed at high temperature fie1 cells, and a vital component of such &el cells must be the availability of a high temperature stable proton-permeable membrane. NASA Glenn Research Center is greatly involved in developing this technology. Other approaches to the high temperature fuel cell involve the use of single- component or almost-single-component electrolytes that provide a path for protons through the cell. A heavily researched case is the phosphoric acid fuel cell, in which the electrolyte is almost pure phosphoric acid and the cathode reaction produces water directly. The phosphoric acid fie1 cell delivers an open circuit voltage of 0.9 V falling to about 0.7 V under operating conditions at 170 C. The proton transport mechanism is mainly vehicular in character according to the viscosity/conductance relation. Here we describe some Proton Transfer Ionic Liquids (PTILs) with low vapor pressure and high temperature stability that have conductivities of unprecedented magnitude for non-aqueous systems. The first requirement of an ionic liquid is that, contrary to experience with most liquids consisting of ions, it must have a melting point that is not much above room temperature. The limit commonly suggested is 100 C. PTILs constitute an interesting class of non-corrosive proton-exchange electrolyte, which can serve well in high temperature (T = 100 - 250 C) fuel cell applications. We will present cell performance data showing that the open circuit voltage output, and the performance of a simple H2(g)Pt/PTIL/Pt/O2(g) fuel cell may be superior to those of the equivalent phosphoric acid electrolyte fuel cell both at ambient temperature and temperatures up to and above 200 C. My work at NASA Glenn Research Center during this summer is to develop and characterize proton exchange membranes doped with ionic liquids. The main techniques used to characterize these materials are: Impedance Spectroscopy, NMR, DSC, TGA, DMA, IR, and SEM ...

Belieres, Jean-Philippe↗
NASA NTRS1975

Coulomb collisions of ring current particles: Indirect source of heat for the ionosphere

The additional energy requirements of the topside ionosphere during a magnetic storm are less than one quarter of the ring current energy. This energy is supplied largely by Coulomb collisions of ring current protons of energy less than about 20 keV with background thermal electrons which conduct the heat to the ionosphere. Past criticisms are discussed of this mechanism for the supply of energy to the SAR-arc and neighboring regions of the ionosphere.

Cole, K. D.↗
NASA NTRS1977

Analogies between respiration and a light-driven proton pump as sources of energy for active glutamate transport in Halobacterium halobium

Halobacterium halobium is known to contain sheets of bacteriorhodopsin, a pigment which upon exposure to light undergoes cyclic protonation and deprotonation, resulting in net H(+) translocation. In this paper, experiments were conducted to test H. halobium cell envelope vesicles for respiration-induced glutamate uptake. It is shown that glutamate transport in H. halobium cell envelope vesicles can occur as a result of respiration, as well as light acting on bacteriorhodopsin. Glutamate transport can be energized by the oxidation of dimethyl phenylenediamine, and the properties of the transport system are entirely analogous to those observed with illumination as the source of energy. In the case of respiration-dependent glutamate transport, the transportation is also driven by a Na(+) gradient, thereby confirming the existence of a single glutamate transport system independent of the source of energy. The analogy observed is indirect evidence that the cytochrome oxidase of H. halobium functions as a H(+) pump.

Belliveau, J. W.↗
NASA NTRS1989

ARCS 3 ionospheric artificial argon ion beam injections - Waves near the heavy ion gyrofrequencies

Low-frequency electric field data below the proton gyrofrequency are presented for the duration of the argon ion beam experiment conducted as part of the Argon Release for Controlled Studies (ARCS) program. An argon ion beam was injected from the subpayload antiparallel or perpendicular to the magnetic field at altitudes from 250 to 405 km. During the injections, the wave spectra were broadband near the subpayload and narrow-band near heavy ion gyrofrequencies at perpendicular separation distances between 42 and 254 m. It is suggested that the narrow-band waves are associated with both the perpendicular argon ion beam and an unexpected flux of low-energy ions which peaked in energy near 15 eV and pitch angle near 90 deg with respect to the magnetic field.

Erlandson, R. E.↗
NASA NTRS1978

Long-term variations of selected solar wind properties - IMP 6, 7, and 8 results

Studies of the variability of the solar wind are extended to include the minimum of solar cycle 20; attention is given to the He abundance, the relative He-H velocity difference, the He-H temperature ratio, the solar coronal proton density, speed, rms velocity variation, temperature and number flux, and the kinetic and total energy fluxes. The solar wind data are from observations conducted by the IMP-6, -7 and -8 satellites. A well-developed corotating stream structure appearing in January 1973 and disappearing in mid-1976 receives particular consideration. An increase in proton number and total energy fluxes after September 1972 may be due to areal expansion of both polar coronal holes, and may be associated with compression of the low-speed equatorial disk-shaped region postulated to surround the sun in interplanetary space.

Feldman, W. C.↗