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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 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
NASA NTRS2006

Self-Consistent Ring Current Modeling with Propagating Electromagnetic Ion Cyclotron Waves in the Presence of Heavy Ions

The self-consistent treatment of the RC ion dynamics and EMIC waves, which are thought to exert important influences on the ion dynamical evolution, is an important missing element in our understanding of the storm-and recovery-time ring current evolution. Under certain conditions, relativistic electrons, with energies 21 MeV, can be removed from the outer radiation belt by EMIC wave scattering during a magnetic storm. That is why the modeling of EMIC waves is critical and timely issue in magnetospheric physics. To describe the RC evolution itself this study uses the ring current-atmosphere interaction model (RAM). RAM solves the gyration and bounce-averaged Boltzmann-Landau equation inside of geosynchronous orbit. Originally developed at the University of Michigan, there are now several branches of this model currently in use as describe by Liemohn namely those at NASA Goddard Space Flight Center This study will generalize the self-consistent theoretical description of RC ions and EMIC waves that has been developed by Khazanov and include the heavy ions and propagation effects of EMIC waves in the global dynamic of self-consistent RC - EMIC waves coupling. The results of our newly developed model that will be presented at GEM meeting, focusing mainly on the dynamic of EMIC waves and comparison of these results with the previous global RC modeling studies devoted to EMIC waves formation. We also discuss RC ion precipitations and wave induced thermal electron fluxes into the ionosphere.

Khazanov, George V.↗
NASA NTRS2006

Self-Consistent Model of Magnetospheric Ring Current and Propagating Electromagnetic Ion Cyclotron Waves: Waves, Precipitating Ring Current Ions, and Thermal Electron Heating - 2

This paper is dedicated to further presentations and discussions of the results from our new global self-consistent theoretical model of interacting ring current ions and electromagnetic ion cyclotron waves [Khazanov et al., 2006; here referred to as Paper 1]. In order to adequately take into account the wave propagation and refraction in a multi-ion plasmasphere, we explicitly include the ray tracing equations in our previous self-consistent model and use the general form of the wave kinetic equation [for details see Paper 1]. To demonstrate the effects of the EMIC wave propagation and refraction on the RC proton precipitations and heating of the thermal plasmaspheric electrons we simulate the May 1998 storm. The main findings of our simulation can be summarized as follows. Firstly, the wave induced precipitations have a quite fine structure, and are highly organized by location of the plasmapause gradient. The strongest fluxes of about 4 (raised dot) 10(exp 6) [(cm (raised dot) s (raised dot) sr)(sup -l)] are observed during the main and early recovery phases of the storm. The very interesting and probably more important finding is that in a number of cases the most intense precipitating fluxes are not simply connected to the most intense EMIC waves. The character of the EMIC wave power spectral density distribution over the equatorial wave normal angle is an extremely crucial for the effectiveness of the RC ion scattering. Secondly, comparison of the global proton precipitating patterns with the results from other ring current model [Kozyra et al., 1997] reveals that although we observe a qualitative agreement between localizations of the wave induced fluxes in the models, there is no quantitative agreement between the magnitudes of these fluxes. These differences are mainly due to a qualitative difference between the characters of the EMIC wave power spectral density distributions over the equatorial wave normal angle. Finally, the two energy sources to the plasmaspheric electrons are considered; (i) the heat fluxes caused by the EMIC wave energy absorption due to Landau resonance, and (ii) the heat fluxes due to Coulomb energy degradation of the RC o(+) ions. The heat fluxes caused by the EMIC wave energy absorption due to Landau resonance are observed in the postnoon-premidnight MLT sector, and maximize at the magnitude of 10l1 (eV/(cm(sup 2)(raised dot) s) at L=3.25, MLT=22 at 3400 UT after 1 May, 0000 UT. The greatest Coulomb energy deposition rates are about 2 (raised dot) 10(sup 10)(eV/(cm(sup 2)(raised dot) s) and observed during two periods; 32-48 hours, and 76-86 hours after 1 May, 0000 UT. The theoretically derived spatial structure of the thermal electron heating caused by interaction of the RC with plasmasphere is strongly supported by concurrent and conjugate plasma measurements from the plasmasphere, the RC, and the topside ionosphere [Gurgiolo et al., 20051.

Khazanov, G. V.↗
NASA NTRS2006

Self-Consistent Ring Current Modeling with Propagating Electromagnetic Ion Cyclotron Waves in the Presence of Heavy Ions

The self-consistent treatment of the RC ion dynamics and EMlC waves, which are thought to exert important influences on the ion dynamical evolution, is an important missing element in our understanding of the storm-and recovery-time ring current evolution. Under certain conditions, relativistic electrons, with energies greater than or equal to 1 MeV, can be removed from the outer radiation belt by EMlC wave scattering during a magnetic storm (Summers and Thorne, 2003; Albert, 2003). That is why the modeling of EMlC waves is critical and timely issue in magnetospheric physics. This study will generalize the self-consistent theoretical description of RC ions and EMlC waves that has been developed by Khazanov et al. [2002, 2003] and include the heavy ions and propagation effects of EMlC waves in the global dynamic of self-consistent RC - EMlC waves coupling. The results of our newly developed model that will be presented at Huntsville 2006 meeting, focusing mainly on the dynamic of EMlC waves and comparison of these results with the previous global RC modeling studies devoted to EMlC waves formation. We also discuss RC ion precipitations and wave induced thermal electron fluxes into the ionosphere.

Khazanov, G. V.↗
NASA NTRS2007

Space Plasma Ion Processing of Ilmenite in the Lunar Soil: Insights from In-Situ TEM Ion Irradiation Experiments

Space weathering on the moon and asteroids results largely from the alteration of the outer surfaces of regolith grains by the combined effects of solar ion irradiation and other processes that include deposition of impact or sputter-derived vapors. Although no longer considered the sole driver of space weathering, solar ion irradiation remains a key part of the space weathering puzzle, and quantitative data on its effects on regolith minerals are still in short supply. For the lunar regolith, previous transmission electron microscope (TEM) studies performed by ourselves and others have uncovered altered rims on ilmenite (FeTiO3) grains that point to this phase as a unique "witness plate" for unraveling nanoscale space weathering processes. Most notably, the radiation processed portions of these ilmenite rims consistently have a crystalline structure, in contrast to radiation damaged rims on regolith silicates that are characteristically amorphous. While this has tended to support informal designation of ilmenite as a "radiation resistant" regolith mineral, there are to date no experimental data that directly and quantitatively compare ilmenite s response to ion radiation relative to lunar silicates. Such data are needed because the radiation processed rims on ilmenite grains, although crystalline, are microstructurally and chemically complex, and exhibit changes linked to the formation of nanophase Fe metal, a key space weathering process. We report here the first ion radiation processing study of ilmenite performed by in-situ means using the Intermediate Voltage Electron Microscope- Tandem Irradiation facility (IVEM-Tandem) at Argonne National Laboratory. The capability of this facility for performing real time TEM observations of samples concurrent with ion irradiation makes it uniquely suited for studying the dose-dependence of amorphization and other changes in irradiated samples.

Christoffersen, R.↗
NASA NTRS2018

Computational Investigation of the Near-Field Plasma Plume in Ion-Ion Propulsion

A two-fluid computational model of plasma flows was developed to investigate the plume of an ion-ion propulsion system. The densities of positive and negative ions, along with the associated values of net charge, electric field, and electric potential were calculated throughout the domain. The computational domain was chosen to be large enough (25 thruster diameters downstream of the accelerating grids) to examine the neutralization of the plume. The resulting plasma electric potential and charge neutrality at the downstream end of the domain are shown. The results from this simulation are compared to existing literature on ion-ion plasma thrusters.

Sankaran, K.↗
DOE OSTI2018

Comparison of Different Ion Mobility Setups Using Poly (Ethylene Oxide) PEO Polymers: Drift Tube, TIMS, and T-Wave Comparison of Different Ion Mobility Setups Using Poly (Ethylene Oxide) PEO Polymers: Drift Tube, TIMS, and T-Wave

Over the years, polymer analyses using ion mobility-mass spectrometry (IM-MS) measurements have been performed on different ion mobility spectrometry (IMS) setups. In order to be able to compare literature data taken on different IM(-MS) instruments, ion heating and ion temperature evaluations have already been explored. Nevertheless, extrapolations to other analytes are difficult and thus straightforward same-sample instrument comparisons seem to be the only reliable way to make sure that the different IM(-MS) setups do not greatly change the gas-phase behavior. We used a large range of degrees of polymerization (DP) of poly(ethylene oxide) PEO homopolymers to measure IMS drift times on three different IM-MS setups: a homemade drift tube (DT), a trapped (TIMS), and a traveling wave (T-Wave) IMS setup. The drift time evolutions were followed for increasing polymer DPs (masses) and charge states, and they are found to be comparable and reproducible on the three instruments. .

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Ion Tracks and Microstructures in Barium Titanate Irradiated with Swift Heavy Ions: A Combined Experimental and Computational Study

Tetragonally structured BaTiO3 single crystals were irradiated using 635 MeV 238U+ ions to fluences of 1E7, 5E10 and 1.4E12 ions/cm2 at room temperature. Subsequent sample characterizations were performed using ion channeling, x-ray diffraction (XRD), helium ion microscopy, and transmission electron microscopy. The results show that there are lattice relaxation and recovery of pre-existing defects in the irradiated samples. Various structures representing different regimes of electronic and nuclear interactions along the ion track are observed. The track on the surface has an amorphous core of up to ~10 nm in diameter, surrounded by a strained lattice structure. The core size is roughly proportional to the square root of the electronic stopping power. Satellite-like defects around the core are also present. The ring of cubic phase expected to form around the amorphous core does not appear, probably due to a reversible phase transition as confirmed by an in-situ XRD study. Modeling and simulation are also attempted to interpret the data and gain physical insights. We have developed a partial charge model for cubic BaTiO3 that reproduces its lattice constants, elastic constants, and melting temperature. Using the interatomic potential, we have performed molecular dynamics simulations of the irradiation damage in BaTiO3. The results show that an amorphous track of ~1.2 nm in radius forms under thermal energy deposition at dE(T)/dx = 5 keV/nm. At 20 keV/nm, the radius increases to ~4.5 nm with an order of magnitude increase in the number of defects. The simulation also reveals details of the bonding environments and shows that the amorphous zones produced at different dE(T)/dx values have different densities. The combined experimental and computational data suggest that there is a significant interfacial recrystallization of the as-created amorphous cores during the cooling-down stage of thermal spikes.

barium titanate↗
DOE OSTI2019

Vanadium Oxide Pillared by Interlayer Mg 2+ Ions and Water as Ultralong-Life Cathodes for Magnesium-Ion Batteries

Magnesium-ion batteries (MIBs) show great potential for large-scale energy storage because of the advantages of low cost and safety, but their application is severely hindered by the difficulty in finding desirable electrode materials. In this work, we develop a bilayer-structured vanadium oxide (Mg 0.3 V 2 O 5 ·1.1H 2 O) with synergistic effect of Mg 2+ ions and lattice water as the cathode material for MIBs. The pre-intercalated Mg 2+ ions provide high electronic conductivity and excellent structural stability. The lattice water enables fast Mg 2+ ions mobility because of its charge shielding effect. As a result, the Mg 0.3 V 2 O 5 ·1.1H 2 O exhibits excellent rate performance and an unprecedented cycling life with capacity retention of 80.0% after 10,000 cycles. Furthermore, the Mg 0.3 V 2 O 5 ·1.1H 2 O exhibits good electrochemical performance in full MIBs. This scalable Mg 2+ host material is an enticing candidate as a cathode for MIBs, and its high performance is expected to meet the requirements for large-scale storage applications.

25 ENERGY STORAGE↗
DOE OSTI2018

Sb nanoparticles encapsulated in 3D porous carbon as anode material for lithium-ion and potassium-ion batteries

Highlights: • The Sb nanoparticle completely embedded in 3D porous carbon (Sb@PC) was synthesized. • This novel 3D structure contribute to relieve the intense volume expansion while ensure the integrity of the structure. • As Li-ion and K-ion batteries anode materials, which both showed excellent electrochemical performance. - Abstract: In the current research project, we have synthesized a novel Sb/Carbon nanocomposite with 3D porous structure which is successfully applied to the Li/K-ion batteries as anode materials. The unique structure shows the homogeneous Sb nanoparticles embedded into a 3D porous carbon (Sb@PC), relieving the intense volume expansion of inner Sb alloying and contributing to the integrity of the structure. As anode materials of Li-ion and K-ion batteries, they both showed an excellent electrochemical performance.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2017

Unravelling the origin of irreversible capacity loss in NaNiO 2 for high voltage sodium ion batteries

Layered transition metal compounds have attracted much attention due to their high theoretical capacity and energy density for sodium ion batteries. However, this kind of material suffers from serious irreversible capacity decay during the charge and discharge process. Here, using synchrotron-based operando transmission X-ray microscopy and high-energy X-ray diffraction combined with electrochemical measurements, the visualization of the dissymmetric phase transformation and structure evolution mechanism of layered NaNiO2 material during initial charge and discharge cycles are clarified. Phase transformation and deformation of NaNiO2 during the voltage range of below 3.0 V and over 4.0 V are responsible for the irreversible capacity loss during the first cycling, which is also confirmed by the evolution of reaction kinetics behavior obtained by the galvanostatic intermittent titration technique. These findings reveal the origin of the irreversibility of NaNiO2 and offer valuable insight into the phase transformation mechanism, which will provide underlying guidance for further development of high-performance sodium ion batteries.

high voltage↗
DOE OSTI2024

Bioleaching ion-unexchangeable rare earth in ion-adsorption type rare earth waste tailing

Ion-adsorption type rare earth ores (IREO) in China serve as the primary source of medium and heavy rare earth globally. With the rapidly growing demand for rare earth elements (REEs) and the dwindling supply of premium IREO, enhancing the recovery of REEs, especially the ion-unexchangeable REEs with ultra-low content and ambiguous speciation from IREO or its tailing, has become a critical trend and challenge. Here, this study identified the occurrences of ion-unexchangeable REEs, primarily detected in Fe-enriched minerals, xenotime, and monazite of IREO using TESCAN integrated mineral analyzer (TIMA) and laser ablation inductively coupled plasma mass spectrometer (LA-ICP-MS) analysis. To extract these elusive REEs, a bioleaching technique utilizing Aspergillus niger (A. niger) metabolites was proposed, achieving a leaching yield of 31.4 wt%. Complementary sequential chemical extraction methods (SCEM), X-ray photoelectron spectroscopy (XPS), and density functional theory (DFT) calculations further elucidate the underlying mechanism, involving the carboxylic acid produced by the metabolic process of microbes that dissolves goethite by disrupting Fe—O bonds and liberating REEs, which complexed with carboxylate (R—COO—), to promote further dissolution. This work offers insight into enhancing the recovery of ion-unexchangeable REEs from IREO or its tailing, paving the way for sustainable and efficient rare earth mining practices.

42 ENGINEERING↗
DOE OSTI2016

Effects of Propylene Carbonate Content in CsPF 6 -Containing Electrolytes on the Enhanced Performances of Graphite Electrode for Lithium-Ion Batteries

The effects Of propylene carbonate (PC) content in CsPF6-containing electrolytes on the performances of graphite electrode in lithium half cells and in graphite parallel to LiNi0.80Co0.15Al0.05O2 (NCA) full cells are investigated. It is found that the performance of graphite electrode is significantly-affected by PC content in the CsPF6-containing electrolytes. An optimal PC content of 20% by weight in the solvent mixtures is identified. The enhanced electrochemical performance of graphite electrode can be attributed to the synergistic effects of the PC solvent and the Cs+ additive. The synergistic effects of Cs+ additive and appropriate amount of PC enable the formation of a robust, ultrathin, and compact solid electrolyte interphase (SEI) layer on the surface of graphite electrode, which is only permeable for desolvated Li+ ions and allows fast Li+ ion transport through it. Therefore, this SEI layer effectively suppresses the PC cointercalation and largely alleviates the Li dendrite formation on graphite electrode during lithiation even at relatively high current densities. The presence of low-melting-point PC solvent improves the sustainable operation of graphite parallel to NCA full cells under a wide temperature range. The fundamental findings also shed light On the importance of manipulating/maintaining the electrode/electrolyte interphasial stability in various energy-storage devices.

25 ENERGY STORAGE↗
DOE OSTI2013

The change of microstructure and thermal properties in ion irradiated carbon nanotube mats as a function of ion penetration depth

A stack of three carbon nanotube (CNT) mats was irradiated with 3 MeV He ions. The change in structural and thermal properties of individual mats as a function of ion penetration depth was characterized using electron microscopy and laser flash techniques. Ion irradiation can enhance thermal conductivity of the mats by introducing inter-tube displacements, which improve phonon transport across adjacent nanotubes. The enhancement, however, is reduced at higher damage levels due to the increasing phonon-defect scattering within the tubes. This study demonstrates the feasibility of using ion irradiation to manipulate thermal transport in carbon nanotubes.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2014

Plasma characteristics of single- and dual-electrode ion source systems utilized in low-energy ion extraction

Discharge characteristics in the upstream as well as in the downstream regions of a 50-eV positive ion beam were measured along the beam axis. Single- and dual-electrode configurations made of 0.1-mm diameter tungsten wires were tested. By varying the upstream discharge parameters, the shape of the sheath edge around the extractors, which can either be “planar” or “cylindrical,” can be controlled. The sheath eventually affected the simultaneous extraction of ions and neutralizing electrons. The dual-electrode configuration at the lower discharge current, revealed a homogeneous discharge downstream. At this condition, the edge of the sheath can be inferred to be “planar” which allowed the uniform extraction and propagation of low-energy ions at longer distances. The dual-electrode configuration was capable of transmitting low-energy ions up to 70 mm downstream.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2014

Oblique propagation of ion acoustic soliton-cnoidal waves in a magnetized electron-positron-ion plasma with superthermal electrons

The oblique propagation of ion-acoustic soliton-cnoidal waves in a magnetized electron-positron-ion plasma with superthermal electrons is studied. Linear dispersion relations of the fast and slow ion-acoustic modes are discussed under the weak and strong magnetic field situations. By means of the reductive perturbation approach, Korteweg-de Vries equations governing ion-acoustic waves of fast and slow modes are derived, respectively. Explicit interacting soliton-cnoidal wave solutions are obtained by the generalized truncated Painlevé expansion. It is found that every peak of a cnoidal wave elastically interacts with a usual soliton except for some phase shifts. The influence of the electron superthermality, positron concentration, and magnetic field obliqueness on the soliton-cnoidal wave are investigated in detail.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2014

Line spectrum and ion temperature measurements from tungsten ions at low ionization stages in large helical device based on vacuum ultraviolet spectroscopy in wavelength range of 500–2200 Å

Vacuum ultraviolet spectra of emissions released from tungsten ions at lower ionization stages were measured in the Large Helical Device (LHD) in the wavelength range of 500–2200 Å using a 3 m normal incidence spectrometer. Tungsten ions were distributed in the LHD plasma by injecting a pellet consisting of a small piece of tungsten metal and polyethylene tube. Many lines having different wavelengths from intrinsic impurity ions were observed just after the tungsten pellet injection. Doppler broadening of a tungsten candidate line was successfully measured and the ion temperature was obtained.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2014

Enhanced 1.53 μm emission of Er{sup 3+} ions in phosphate glass via energy transfer from Cu{sup +} ions

Optimizing the efficiency of Er{sup 3+} emission in the near-infrared telecommunication window in glass matrices is currently a subject of great interest in photonics research. In this work, Cu{sup +} ions are shown to be successfully stabilized at a high concentration in Er-containing phosphate glass by a single-step melt-quench method, and demonstrated to transfer energy to Er{sup 3+} thereby enhancing the near-infrared emission about 15 times. The spectroscopic data indicate an energy conversion process where Cu{sup +} ions first absorb photons broadly around 360 nm and subsequently transfer energy from the Stokes-shifted emitting states to resonant Er{sup 3+} absorption transitions in the visible. Consequently, the Er{sup 3+} electronic excited states decay and the {sup 4}I{sub 3/2} metastable state is populated, leading to the enhanced emission at 1.53 μm. Monovalent copper ions are thus recognized as sensitizers of Er{sup 3+} ions, suggesting the potential of Cu{sup +} co-doping for applications in the telecommunications, solar cells, and solid-state lasing realizable under broad band near-ultraviolet optical pumping.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗