Search NASA⌕ Search

SEARCH · Search NASA

Results for “ALUMINIUM IONS”

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.

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

At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Advanced rechargeable aluminium ion battery with a high-quality natural graphite cathode

There has been some interest in aluminium ion batteries with aluminium anodes, graphite cathodes and ionic liquid electrolytes has increased; however, much remains to be done to increase the cathode capacity and to understand details of the anion–graphite intercalation mechanism. An aluminium ion battery cell made using pristine natural graphite flakes achieves a specific capacity of B110 mAhg -1 with Coulombic efficiency B98%, at a current density of 99mAg -1 (0.9 C) with clear discharge voltage plateaus (2.25–2.0 V and 1.9–1.5 V). The cell has a capacity of 60mAhg -1 at 6 C, over 6,000 cycles with Coulombic efficiency B 99%. Raman spectroscopy shows two different intercalation processes involving chloroaluminate anions at the two discharging plateaus, while C–Cl bonding on the surface, or edges of natural graphite, is found using X-ray absorption spectroscopy. Lastly, theoretical calculations are employed to investigate the intercalation behaviour of choloraluminate anions in the graphite electrode.

25 ENERGY STORAGE↗
DOE OSTI2017

Reversible magnesium and aluminium ions insertion in cation-deficient anatase TiO 2

In contrast to monovalent lithium or sodium ions, the reversible insertion of multivalent ions such as Mg 2+ and Al 3+ into electrode materials remains an elusive goal. In this work, we demonstrate a new strategy to achieve reversible Mg 2+ and Al 3+ insertion in anatase TiO 2 , achieved through aliovalent doping, to introduce a large number of titanium vacancies that act as intercalation sites. We present a broad range of experimental and theoretical characterizations that show a preferential insertion of multivalent ions into titanium vacancies, allowing a much greater capacity to be obtained compared to pure TiO 2 . In conclusion, this result highlights the possibility to use the chemistry of defects to unlock the electrochemical activity of known materials providing a new strategy for the chemical design of materials for practical multivalent batteries.

25 ENERGY STORAGE↗
NASA NTRS1993

Aluminium and hydrogen ions inhibit a mechanosensory calcium-selective cation channel

The tension-dependent activity of mechanosensory calcium-selective cation channels in excised plasmalemmal patches from onion bulb scale epidermis is modulated by pH in the physiologically meaningful range between 4.5 and 7.2. It is rapidly lowered by lowering pH and rapidly raised by raising pH. Channel activity is effectively inhibited by low levels of aluminium ions and activity can be partially restored by washing for a few minutes. We suggest that under normal conditions the sensitivity of the mechanosensory channels to pH of the wall free space plays important roles in regulation of plant activities such as growth. We further suggest that, when levels of acid and aluminium ions in the soil solution are high, they might inhibit similar sensory channels in cells of the root tip, thus contributing critically to the acid soil syndrome.

NASA Discipline Plant Biology↗
DOE OSTI2016

Multiparticle losses in a linear quadrupole Paul trap

A linear quadrupole Paul trap is fabricated for capturing magnesium and aluminium ions. An experimental cycle performed has demonstrated ion capture and holding in a trap with an average ion lifetime of 1.7 s. Modelling of ion dynamics in the trap shows that the main mechanism responsible for losses of hot ions is multiparticle interaction, which results in that a kinetic energy of some ions increases and they leave the trapping zone. This mechanism is completely suppressed if ions are cooled. Another mechanism is the charge exchange; however, it is not substantial at a high average energy of ions produced in the result of an electron impact. Parameters of the trap allow one to perform precision spectroscopic measurements and to control ion quantum states. (laser cooling)

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2021

Understanding of the factors slowing down metakaolin reaction in limestone calcined clay cement (LC3) at late ages

Factors which could explain the slowing down of the metakaolin reaction in LC{sup 3} blends are investigated. Portlandite availability and the presence of aluminium ions in the pore solution are shown not to be limiting factors. Hydrates can only precipitate in solution filled pores. Internal relative humidity measurements indicate that at 28 days solution is present only in pores with radii below 13 nm. An enhancement of metakaolin reaction was obtained at late ages when the larger capillaries are filled with solution. The lower limit of the water filled pores was more difficult to analyse since there is a lack of precision in determining interfacial energies of hydrates and pore solution of the system. However, this study gives an indication of order of magnitude where the growth of hydrates could be slowed down.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Al-doped TiO{sub 2} mesoporous material supported Pd with enhanced catalytic activity for complete oxidation of ethanol

Pd catalysts supported on Al-doped TiO{sub 2} mesoporous materials were evaluated in complete oxidation of ethanol. The catalysts synthesized by wet impregnation based on evaporation-induced self-assembly were characterized by X-ray diffraction, measurement of pore structure, XPS, FT-IR, temperature programmed reduction and TEM. Characteristic results showed that the aluminium was doped into the lattice of mesoporous anatase TiO{sub 2} to form Al-O-Ti defect structure. Catalytic results revealed that Al-doped catalysts were much more active than the pristine one, especially at low temperature (≤200 °C). This should be ascribed to the introduction of aluminium ions that suppressed the strong metal-support interaction and increased the active sites of Pd oxides, enhanced the stabilized anatase TiO{sub 2}, improved well dispersed high valence palladium species with high reducibility and enriched chemisorption oxygen. - Graphical abstract: Al-doped Pd/TiO{sub 2} exhibited optimal catalytic performance for ethanol oxidation and CO{sub 2} yield by the suppression of SMSI. - Highlights: • Palladium catalysts supported on Al-doped TiO{sub 2} mesoporous materials were studied. • The introduction of Al can enhance anatase stabilization and increase defect TiO{sub 2}. • The Pd/Al-TiO{sub 2} catalysts show higher ethanol conversion and CO{sub 2} yield than Pd/TiO{sub 2}. • The influence of Al on SMSI and catalytic performance were evaluated by TPR and XPS.

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

Cation substitution in β-tricalcium phosphate investigated using multi-nuclear, solid-state NMR

The substitution of aluminium, gallium and sodium cations into β-tricalcium phosphate (β-TCP; Ca{sub 3}(PO{sub 4}){sub 2}) has been investigated, and the Ca sites involved successfully determined, using a combination of 1D {sup 31}P, {sup 27}Al, {sup 71}Ga, {sup 23}Na and {sup 43}Ca (natural abundance) NMR and 2D {sup 27}Al({sup 31}P), {sup 71}Ga({sup 31}P) and {sup 23}Na({sup 31}P) rotary-resonance-recoupled heteronuclear multiple-quantum correlation (R{sup 3}-HMQC) NMR. Over the compositional range studied, substitution of Ca{sup 2+} by Al{sup 3+} or Ga{sup 3+} was observed only on the Ca(5) site, whilst substitution by Na{sup +} was confined to the Ca(4) site. Some AlPO{sub 4} or GaPO{sub 4} second phase was observed at the highest doping levels in the Al{sup 3+} and Ga{sup 3+} substituted samples. - Graphical abstract: 2D contour plots with skyline projections showing recoupling of {sup 27}Al, {sup 71}Ga and {sup 23}Na to different {sup 31}P sites. - Highlights: • β-Ca{sub 3}(PO{sub 4}){sub 2} has been prepared pure and also with Al{sup 3+}, Ga{sup 3+} and Na{sup +} substituents. • Multi-nuclear 1D NMR and heteronuclear X({sup 31}P) recoupling have been used. • Models for substitution correctly predict site preference and occupancy. • Progressive changes in {sup 31}P spectra have been explained. • Al{sup 3+} and Ga{sup 3+} substitute onto the Ca(5) site, and Na{sup +} onto the Ca(4) site.

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

Investigating the plasma parameters of an Ar/O{sub 2} discharge during the sputtering of Al targets in an inverted cylindrical magnetron

The plasma parameters and reaction kinetics in an inverted cylindrical magnetron chamber have been studied with an energy resolved mass spectrometer during the sputtering of aluminum targets in an Ar/O{sub 2} discharge. Mixtures of argon and oxygen were studied as a function of oxygen percentage (0%–90%) in the discharge. The plasma was powered at 4 kW and 40 kHz at a process pressure of 5 mTorr. Al{sup +}, Al, AlO, AlO{sup +}, O{sub 2}{sup +}, O{sup +}, Al{sub 2}O{sup +}, and Ar{sup +} were among the species detected in the discharge. The deposition rate of the deposited thin film decreased with increasing oxygen percentage in the discharge and results indicated that the pure gamma-alumina was obtained when the percentage of oxygen was approximately 70%. The linear plot of energy distributions of the positively charged film forming species changed from a single peak to a bimodal distribution as the percentage of oxygen exceeds 65%. In a log plot, however, the distributions showed multiple peaks ranging from 2 eV to 78 eV. Fluctuations of about 1 eV in peak energies were observed.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Local structure and structural rigidity of the green phosphor β-SiAlON:Eu{sup 2+}

Eu{sup 2+} inserted in β-Si{sub 3−x}Al{sub x}O{sub x}N{sub 4−x} is a material that shows exceptional promise as a green-emitting phosphor. Synchrotron X-ray and neutron scattering, in conjunction with first-principles calculations and Eu L{sub 3} X-ray absorption measurements, yield a consistent picture of the composition, and the favorable position for Eu{sup 2+} substitution in the crystal structure. The Debye temperature Θ{sub D}, which is a proxy for structural rigidity relating to effectiveness as a phosphor, is very high for the starting β-Si{sub 3}N{sub 4} framework and is determined to decrease only slightly for the small amounts of Al{sup 3+} and O{sup 2−} co-substitution that are required for charge balance associated with Eu{sup 2+} insertion.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Electronic state of Er in sputtered AlN:Er films determined by magnetic measurements

The optoelectronic and piezoelectric properties of AlN:Er thin films have been of great recent interest for potential device applications. In this work, the focus is on the electronic state of Er in AlN:Er thin films prepared by reactive magnetron sputtering on (001) p-type Si substrate. X-ray diffraction shows that Er doping expands the lattice and the AlN:Er film has preferential c-plane orientation. To determine whether Er in AlN:Er is present as Er metal, Er{sub 2}O{sub 3}, or Er{sup 3+} substituting for Al{sup 3+}, detailed measurements and analysis of the temperature dependence (2 K–300 K) of the magnetization M at a fixed magnetic field H along with the M vs. H data at 2 K up to H = 90 kOe are presented. The presence of Er{sub 2}O{sub 3} and Er metal is ruled out since their characteristic magnetic transitions are not observed in the AlN:Er sample. Instead, the observed M vs. T and M vs. H variations are consistent with Er present as Er{sup 3+} substituting for Al{sup 3+} in AlN:Er at a concentration x = 1.08% in agreement with x = 0.94% ± 0.20% determined using x-ray photoelectron spectroscopy (XPS). The larger size of Er{sup 3+} vs. Al{sup 3+}explains the observed lattice expansion of AlN:Er.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2018

Biogas reforming over Ni catalysts dispersed in different mixed oxides containing Zn2+, Al3+ and Zr4+cations

Highlights: • The oxides mixture containing NiO, ZnO, Al{sub 2}O{sub 3}, NiAl{sub 2}O{sub 4} and ZnAl{sub 2}O{sub 4} was detected. • The results exhibited intermediate interactions between Ni0 and other phases. • Dry reforming of methane was applied to production of synthesis gas. • Deposition of the carbon filamentous on the catalysts surface was observed. - Abstract: The active phase plays an important role in the catalytic activity. However, its applicability is directly associated with other present phases in the mixture. In view of this, we report the performance of Ni catalysts dispersed on mixed oxides containing Zn{sup 2+}, Al{sup 3+} and Zr{sup 4+}cations in biogas reforming. For this purpose, the samples were characterized by X-ray powder diffraction, which showed the formation of a homogeneous mixture of binary (NiO, ZnO, ZrO{sub 2} and Al{sub 2}O{sub 3}) and ternary (NiAl{sub 2}O{sub 4} and ZnAl{sub 2}O{sub 4}) oxides. The temperature-programmed reduction (H{sub 2}-TPR) provided information on the catalyst reduction. The performance of the catalysts was evaluated using two reduction temperatures (650 °C and 750 °C). The reactions were carried out at 750 °C, where the Ni/ZnAlZr catalyst presented the highest CO{sub 2} conversion attributed to the basic sites, which favored the CO{sub 2} adsorption. Otherwise, the Ni/ZnZr catalyst (reduced at 650 °C) showed a high CH{sub 4} conversion. The catalysts were also reduced at 750 °C and a lower conversion of both reactants (CH{sub 4} and CO{sub 2}) was observed. We argued that the agglomeration process during the reduction condition deteriorates the performance of the catalysts reduced at 750 °C.

09 BIOMASS FUELS↗
DOE OSTI2012

Lamellar {gamma}-AlOOH architectures: Synthesis and application for the removal of HCN

Using hexadecyl trimethyl ammonium bromide (CTAB) as a structure-directing agent and precipitator, the complete synthesis of lamellar {gamma}-AlOOH architectures was successfully accomplished via a hydrothermal route. Different product structures were obtained by varying the molar ratio of aluminum nitrate and CTAB. Several techniques, including X-ray powder diffraction, Fourier transform infrared spectroscopy, field-emission scanning electron microscopy, transmission electron microscopy, and differential scanning calorimetry thermal analysis, were used to characterize the products. The effects of CTAB concentration, reaction temperature and time, and the molar ratio of Al{sup 3+}/CTAB on the product morphologies were investigated. The nitrogen adsorption and desorption measurements indicated that the {gamma}-AlOOH architectures possess a Brunauer-Emmett-Teller surface area of approximately 75.02 m{sup 2}/g. It was also demonstrated that 10 mg {gamma}-AlOOH architectures can remove 45.3% of the HCN (1.68 {mu}g/mL) from model wastewater. When 0.03 mg/cig {gamma}-AlOOH architectures were combined with cigarette paper, 8.12% of the present HCN was adsorbed. These results indicate that lamellar {gamma}-AlOOH architectures may be a potential adsorbent for removing HCN from highly toxic pollutant solutions and harmful cigarette smoke. Highlights: Black-Right-Pointing-Pointer Hexadecyl trimethyl ammonium bromide (CTAB) was used as a structure-directing agent and precipitator. Black-Right-Pointing-Pointer Hydrothermal treatment enables growth of lamellar {gamma}-AlOOH architectures. Black-Right-Pointing-Pointer Lamellar {gamma}-AlOOH architectures were demonstrated to exhibit high BET surface area and excellent adsorptive capacity. Black-Right-Pointing-Pointer HCN in contaminated water and cigarette smoke can be effectively removed by the prepared lamellar {gamma}-AlOOH superstructures.

36 MATERIALS SCIENCE↗
DOE OSTI2014

Exchange bias effect in Bi{sub 2}Fe{sub 3}AlO{sub 9} ceramics

The exchange bias (EB) effect is observed in Bi{sub 2}Fe{sub 3}AlO{sub 9} polycrystalline ceramics. The EB field (H{sub EB}), vertical magnetization shift, and coercive field show a strong dependence on the cooling fields. When a larger applied field is used to measure the hysteresis loop, the EB effect is suppressed. The induced spin-glass-like phase via Al{sup 3+} doping is responsible for the EB effect below the spin-glass temperature (T{sub SG}) of ∼25 K. Moreover, the H{sub EB} varies nonmonotonically with temperature above T{sub SG}, which is interpreted using a random field model with the exchange coupling between ferromagnetic clusters and an antiferromagnetic phase.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
NASA NTRS1992

Characterization of GTP binding and hydrolysis in plasma membranes of zucchini

We have investigated the possibility that G-protein-like entities may be present in the plasma membrane (PM) of zucchini (Cucurbita pepo L.) hypocotyls by examining a number of criteria common to animal and yeast G-proteins. The GTP binding and hydrolysis characteristics of purified zucchini PM are similar to the characteristics of a number of known G-proteins. Our results demonstrate GTP binding to a single PM site having a Kd value between 16-31 nM. This binding has a high specificity for guanine nucleotides, and is stimulated by Mg2+, detergents, and fluoride or aluminium ions. The GTPase activity (Km = 0.49 micromole) of zucchini PM shows a sensitivity to NaF similar to that seen for other G-proteins. Localization of GTP mu 35S binding to nitrocellulose blots of proteins separated by SDS-PAGE indicates a 30-kDa protein as the predominant GTP-binding species in zucchini PM. Taken together, these data indicate that plant PM contains proteins which are biochemically similar to previously characterized G-proteins.

NASA Discipline Plant Biology↗
DOE OSTI2019

Cationic Effect of Ferrous Ions on Sulfide Capacity of CaO-Fe{sub t}O-Al{sub 2}O{sub 3}-SiO{sub 2} Slag System

The cationic effect of ferrous ions on the sulfide capacity of CaO-Fe{sub t}O-Al{sub 2}O{sub 3}-SiO{sub 2} slags was studied from the viewpoint of the ionic structure in the slag using micro-Raman spectroscopy. In the cation-excess region (M{sup 2+}/2(Fe{sup 3+} + Al{sup 3+}) > 1.0), the sulfide capacity was directly proportional to the basicity of the slags, owing to the S{sup 2−} stabilizing effect of excess cations. However, in the cation-deficient region (M{sup 2+}/2(Fe{sup 3+} + Al{sup 3+}) < 1.0), the sulfide capacity was independent of the basicity of the slags owing to the deficiency of cations required for charge compensation with Al{sup 3+} and Fe{sup 3+}. The cation-substitution effect on the sulfide capacity of the CaO-rich slags (Fe{sub t}O/(Fe{sub t}O + CaO < 0.5) exhibited a linear relationship with the Fe{sup 2+} content because Fe{sup 2+} had a stronger affinity with S{sup 2−} compared to that with Ca{sup 2+}. However, in the Fe{sub t}O-rich slags (Fe{sub t}O/(Fe{sub t}O + CaO > 0.5), the sulfide capacity decreased with the increase of the Fe{sup 2+} content owing to the Q{sup n} unit affinity of the Fe{sup 2+} ion. The sulfide capacity was determined by the competition between the Q{sup n} unit affinity and stability of the S{sup 2−} ion, depending on the type of cation. Therefore, the partial covalent bonding between the M{sup 2+} cations (M: Ca, Fe) and aluminosilicate affected the ionic interactions with the S{sup 2−} ions.

36 MATERIALS SCIENCE↗
DOE OSTI2012

Metal versus rare-gas ion irradiation during Ti{sub 1-x}Al{sub x}N film growth by hybrid high power pulsed magnetron/dc magnetron co-sputtering using synchronized pulsed substrate bias

Metastable NaCl-structure Ti{sub 1-x}Al{sub x}N is employed as a model system to probe the effects of metal versus rare-gas ion irradiation during film growth using reactive high-power pulsed magnetron sputtering (HIPIMS) of Al and dc magnetron sputtering of Ti. The alloy film composition is chosen to be x = 0.61, near the kinetic solubility limit at the growth temperature of 500 Degree-Sign C. Three sets of experiments are carried out: a -60 V substrate bias is applied either continuously, in synchronous with the full HIPIMS pulse, or in synchronous only with the metal-rich-plasma portion of the HIPIMS pulse. Alloy films grown under continuous dc bias exhibit a thickness-invariant small-grain, two-phase nanostructure (wurtzite AlN and cubic Ti{sub 1-x}Al{sub x}N) with random orientation, due primarily to intense Ar{sup +} irradiation leading to Ar incorporation (0.2 at. %), high compressive stress (-4.6 GPa), and material loss by resputtering. Synchronizing the bias with the full HIPIMS pulse results in films that exhibit much lower stress levels (-1.8 GPa) with no measureable Ar incorporation, larger grains elongated in the growth direction, a very small volume fraction of wurtzite AlN, and random orientation. By synchronizing the bias with the metal-plasma phase of the HIPIMS pulses, energetic Ar{sup +} ion bombardment is greatly reduced in favor of irradiation predominantly by Al{sup +} ions. The resulting films are single phase with a dense competitive columnar structure, strong 111 orientation, no measureable trapped Ar concentration, and even lower stress (-0.9 GPa). Thus, switching from Ar{sup +} to Al{sup +} bombardment, while maintaining the same integrated incident ion/metal ratio, eliminates phase separation, minimizes renucleation during growth, and reduces the high concentration of residual point defects, which give rise to compressive stress.

36 MATERIALS SCIENCE↗
DOE OSTI2017

Spectra of optical absorption and energy levels diagram of Er{sup 3+} ions in bulk crystals of aluminum nitride

The absorption spectra of the Er{sup 3+} ions embedded in the AlN matrix have been investigated. The admixture of erbium was introduced in bulk AlN crystals by diffusion. The absorption lines, which are associated with the intraconfigurational electronic f–f-transitions from the ground {sup 4}I{sub 15/2}-state to the levels of ion Er{sup 3+} excited states have been observed in the spectral range of 370–700 nm. The transitions to the state levels {sup 4}F{sub 9/2}, {sup 2}H{sub 11/2}, {sup 4}F{sub 7/2}, {sup 4}F{sub 5/2}, {sup 2}H{sub 9/2}, and {sup 4}G{sub 11/2} have been investigated in detail at the temperature T = 2 K. The number of the observed lines for these transitions coincides with the theoretically possible one for the electronic f–f-transitions in the ions Er{sup 3+}, which are in the crystal field with the symmetry below cubic. The narrowness of the observed lines and their number convincingly testify the replacement of preferably one regular crystalline position by erbium ions. The implementation of Er{sup 3+} in the Al{sup 3+} position with the local symmetry C{sub 3v} appears the most probable. The energy positions of the levels of excited states for the investigated transitions have been determined. The diagram of the Er{sup 3+} ion energy levels in the AlN crystals has been built.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2014

Importance of ion bombardment during coverage of Au nanoparticles on their structural features and optical response

This work studies the changes in the optical response and morphological features of 6 ± 1 nm diameter Au nanoparticles (NPs) when covered by a layer of a-Al{sub 2}O{sub 3} by pulsed laser deposition (PLD). The laser fluence used for ablating the Al{sub 2}O{sub 3} target is varied in order to modify the kinetic energy (KE) of the species bombarding the NPs during their coverage. When the ion KE < 200 eV, the structural features and optical properties of the NPs are close to those of uncovered ones. Otherwise, a shift to the blue and a strong damping of the surface plasmon resonance is observed as fluence is increased. There are two processes responsible for these changes, both related to aluminum ions arriving to the substrate during the coverage process, i.e., sputtering of the metal and implantation of aluminum species in the metal. Both processes have been simulated using standard models for ion bombardment, the calculated effective implanted depths allow explaining the observed changes in the optical response, and the use of a size-dependent sputtering coefficient for the Au NPs predicts the experimental sputtering fractions. In spite of the work is based on PLD, the concepts investigated and conclusions can straightforwardly be extrapolated to other physical vapor deposition techniques or processes involving ion bombardment of metal NPs by ions having KE > 200 eV.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗