Engineering Papers⌕ Search

SEARCH · Engineering Papers

Results for “Ions Separations”

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 991 records · Page 55
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Effect of Ionic Strength and Anion Identity on Rare‐Earth Element Chelation by Poly(acrylic acid)

Abstract Rare‐earth elements (REEs) are critical components of many modern technologies, but their efficient separation and purification continue to pose significant challenges. Metal‐binding polymers may enable the development of promising alternative approaches to conventional separation techniques (e.g., solvent extraction), and insights into the interactions between the metal ions and polymers in solution are crucial to such development. In this work, the effect of ionic strength on the chelation of REEs by poly(acrylic acid) is investigated using isothermal titration calorimetry (ITC) to measure the metal‐binding thermodynamics. ITC experiments revealed that when ionic strength increases from increasing the sodium acetate buffer strength, polymer‐REE binding becomes increasingly disfavored. However, when ionic strength is increased by the addition of sodium chloride, binding again becomes increasingly disfavored, but to a lesser extent than when ionic strength increases from increasing the buffer strength. Additionally, the reduction in binding affinity is enthalpically driven when ionic strength is raised with sodium chloride, while it is entropically driven when raised with sodium acetate buffer, suggesting competive binding by the acetate ions. These results highlight the importance of ionic strength in polymer‐metal binding thermodynamics and will guide the development of new processes for the purification of critical metals.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

Emerging investigator series: local pH effects on carbon oxidation in capacitive deionization architectures

In this work, the effect of pH and potential is examined for the oxidation of carbon cloth electrodes used in capacitive deionization (CDI) processes. The degree of oxidation of the electrode surface, examined using the electrode's potential of zero charge (E pzc ) and measured using chronoamperometry and cyclic voltammetry, is found to be strongly correlated to the pH of the solution at the interface. Local pH measurements are examined at anodes and cathodes in full CDI and membrane-assisted capacitive deionization (MCDI) cells at cell voltages ranging from 0.3–1.2 V. The cathode is shown to be basic under charging potentials while the anode is found to be acidic. This local pH is found to be highly transient during charging and discharging in CDI cells while the pH is found to be relatively static in the MCDI cells, maintaining a basic pH at the cathode and an acidic pH at the anode even when the cell is discharged. Ion exchange membranes (IEM) are found to have two functions: (1) limiting co-ion expulsion that results from specific ion adsorption and (2) limiting the effects of parasitic Faradaic reactions on the separation process by stabilizing the local pH thereby mitigating dissolved oxygen reduction at the cathode and lessening carbon oxidation at the anode. Performance comparisons including the salt adsorption capacity and charge efficiency are also compared for these systems.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Jet modification via 𝜋 0 -hadron correlations in Au + Au collisions at $\sqrt{s_{NN}}$ = 200 GeV

High-momentum two-particle correlations are a useful tool for studying jet-quenching effects in the quark-gluon plasma. Angular correlations between neutral-pion triggers and charged hadrons with transverse momenta in the range 4–12 GeV/𝑐 and 0.5–7 GeV/𝑐, respectively, have been measured by the PHENIX experiment in 2014 for Au + Au collisions at $\sqrt{s_{NN}}$ = 200 GeV. Suppression is observed in the yield of high-momentum jet fragments opposite the trigger particle, which indicates jet suppression stemming from in-medium partonic energy loss, while enhancement is observed for low-momentum particles. The ratio and differences between the yield in Au + Au collisions and 𝑝 + 𝑝 collisions, 𝐼 𝐴⁢𝐴 and Δ 𝐴⁢𝐴 , as a function of the trigger-hadron azimuthal separation, Δ⁢𝜙, are measured for the first time at the BNL Relativistic Heavy Ion Collider. Finally, these results better quantify how the yield of low-𝑝 𝑇 associated hadrons is enhanced at wide angle, which is crucial for studying energy loss as well as medium-response effects.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS1973

On the field anomaly of near wakes in a collisionless plasma.

A variational approach is presented for determining the electric field induced by charge separation in the near wake of a large negatively charged body moving at mesothermal speeds in a tenuous plasma. It is shown that the presence of a potential well in the wake is due to the charge separation resulting from the unequal mass motions with which the ambient electrons and ions move into the wake.

Liu, V. C.↗
NASA NTRS1978

An experiment to study energetic particle fluxes in and beyond the earth's outer magnetosphere

This experiment is designed to take advantage of the ISEE Mother/Daughter dual spacecraft system to study energetic particle phenomena in the earth's outer magnetosphere and beyond. Large geometric factor fixed voltage electrostatic analyzers and passively cooled semiconductor detector telescopes provide high time resolution coverage of the energy range from 1.5 to 300 keV for both ions and electrons. Essentially identical instrumentation is placed on the two spacecraft to separate temporal from spatial effects in the observed particle phenomena.

Anderson, K. A.↗
NASA NTRS1979

An electric propulsion long term test facility

An existing test facility was modified to provide for extended testing of multiple electric propulsion thruster subsystems. A program to document thruster subsystem characteristics as a function of time is currently in progress. The facility is capable of simultaneously operating three 2.7-kW, 30-cm mercury ion thrusters and their power processing units. Each thruster is installed via a separate air lock so that it can be extended into the 7m x 10m main chamber without violating vacuum integrity. The thrusters exhaust into a 3m x 5m frozen mercury target. An array of cryopanels collect sputtered target material. Power processor units are tested in an adjacent 1.5m x 2m vacuum chamber or accompanying forced convection enclosure. The thruster subsystems and the test facility are designed for automatic unattended operation with thruster operation computer controlled. Test data are recorded by a central data collection system scanning 200 channels of data a second every two minutes. Results of the Systems Demonstration Test, a short shakedown test of 500 hours, and facility performance during the first year of testing are presented.

Trump, G.↗
NASA NTRS1985

Far-infrared line observations of planetary nebulae. 1: The O 3 spectrum

Observations of the far-infrared fine structure lines of O III have been obtained for six planetary nebulae. The infrared measurements are combined with optical O III line fluxes to probe physical conditions in the gas. From the observed line intensity ratios, a simultaneous solution was obtained for electron temperature and density, as well as means of evaluating the importance of inhomogeneities. Densities determined from the far-infrared O III lines agree well density diagnostics from other ions, indicating a fairly homogeneous density in the emitting gas. Temperatures are determined separately from the O III 4363/5007 A and 5007 A/52 micron intensity ratios and compared. Systematically higher values are derived from the former ratio, which is expected from a nebula which is not isothermal. Allowance for the presence of temperature variations within these nebulae raises their derived oxygen abundances, determinations to be reconciled with the solar value.

Dinerstein, H. L.↗
NASA NTRS1985

Far-infrared line observations of planetary nebulae. I - The forbidden O III spectrum

Observations of the far-infrared fine structure lines of O III have been obtained for six planetary nebulae. The infrared measurements are combined with optical O III line fluxes to probe physical conditions in the gas. From the observed line intensity ratios, a simultaneous solution was obtained for electron temperature and density, as well as means of evaluating the importance of inhomogeneities. Densities determined from the far-infrared O III lines agree well with density diagnostics from other ions, indicating a fairly homogeneous density in the emitting gas. Temperatures are determined separately from the O III 4363/5007 A and 5007 A/52 micron intensity ratios and compared. Systematically higher values are derived from the former ratio, which is expected from a nebula which is not isothermal. Allowance for the presence of temperature variations within these nebulae raises their derived oxygen abundances, determinations to be reconciled with the solar value.

Dinerstein, H. L.↗
NASA NTRS1987

Non-enzymatic synthesis of the coenzymes, uridine diphosphate glucose and cytidine diphosphate choline, and other phosphorylated metabolic intermediates

Using urea and cyanamide, the two condensing agents considered to have been present on the primitive earth, uridine diphosphate glucose (UDPG), cytidine diphosphate choline (CDP-choline), glucose-1-phosphate (G1P), and glucose-6-phosphate (G6P) were synthesized under simulated prebiotic conditions. The reaction products were separated and identified using paper chromatography, thin layer chromatography, enzymatic analyses, and ion-pair reverse-phase high performance liquid chromatography. The possibility of nonenzymatic synthesis of metabolic intermediates on the primitive earth from simple precursors was thus demonstrated.

Mar, A.↗
NASA NTRS1988

GAS 450: A space payload for the People Central Coast Student Experimenters

The Get Away Special 450 is described. This discussion includes the peoples efforts, the experiments, lessons learned, and a few powerful positive steps toward community involvement. The following is a list of experiment titles: Guppies in Space; Electrophoresis of Enzymes in Microgravity; Diffusion of Ions in Solution; Space Cement; Bubbles in Space; Small Particle Studies; and Liquid Separation in Microgravity.

Ray, Glen↗
NASA NTRS1992

Charge, energy, and LET spectra measurements of charged particles in P0006 experiment of LDEF

Measurements are under way of the charged particle radiation environment of the LDEF satellite using stacks of plastic nuclear track detectors (PNTDs) placed in different locations of the satellite. In the initial work, the charge, energy, and linear energy transfer (LET) spectra of charged particles were measured with CR-39 double layer PNTDs located on the west end of the satellite. Primary and secondary stopping heavy ions as well as relativistic galactic cosmic rays (mostly iron particles) were measured separately. The results will be compared with similar measurements in other locations on LDEF with different orientation and shielding conditions. The remarkably detailed study of the charged particle radiation environment of the LDEF satellite will lead to a better understanding of the radiation environment of the Space Station Freedom. It will enable more accurate prediction of single event upsets (SEUs) in microelectronics and, especially, more accurate assessment of the risk, contributed by the different components of the radiation field to the health and safety of crew members.

Benton, E. V.↗
NASA NTRS1993

Waves generated in the vicinity of an argon plasma gun in the ionosphere

Wave and particle observations were made in the close vicinity of an argon plasma gun carned to over 600 km altitude on a sounding rocket. The gun was carned on a subpayload, separated from the main payload early in the flight. Twelve-second argon ion ejections were energized alternately with a peak energy of 100 or 200 eV. They produced waves, with multiple harmonics, in the range of ion cyclotron waves, 10 to 1000 Hz at rocket altitudes. Many of these waves could not be identified as corresponding to the cyclotron frequencies of any of the ions, argon or ambient, known to be present. In addition, the wave frequencies were observed to rise and fall and to change abruptly during a 12-s gun operation. The wave amplitudes, near a few hundred Hertz, were of the order of O. 1 V/m. Some of the waves may be ion-ion hybrid waves. Changes in ion populations were observed at the main payload and at the subpayload during gun operations. A gun-related, field-aligned, electron population also appeared.

Cahill, L. J., Jr.↗
NASA NTRS1998

From the Chemistry Lab to Licensing

This is a story of technology maturation and transfer, and licensing. It traces the history of the recently patented ion- exchange material (IEM) from the accidental discovery that this polymer, a battery separator of marginal performance, picked up copper from distilled water passing through corroded copper tubing in the laboratory, to a point where five organizations and one individual have applied for licenses to manufacture and market it or to use it in a wide variety of applications. This story discusses in detail the problems of converting an immature technology into a mature and eventually commercialized technology, without dedicated resources. Readers will develop an appreciation for how the obstacles to maturation and licensing of the technology were faced and overcome. The lessons learned will be discussed, with the hope of enhancing the technology transfer process.

Savino, Joseph M.↗
NASA NTRS2002

Microgravity Compatible Reagentless Instrumentation for Detection of Dissolved Organic Acids and Alcohols in Potable Water

The Organic Acid and Alcohol Monitor (OAAM) program has resulted in the successful development of a computer controlled prototype analyzer capable of accurately determining aqueous organic acids and primary alcohol concentrations over a large dynamic range with high sensitivity. Formic, acetic, and propionic acid were accurately determined at concentrations as low as 5 to 10 micrograms/L in under 20 minutes, or as high as 10 to 20 mg/L in under 30 minutes. Methanol, ethanol, and propanol were determined at concentrations as low as 20 to 100 micrograms/L, or as high as 10 mg/L in under 30 minutes. Importantly for space based application, the OAAM requires no reagents or hazardous chemicals to perform these analyses needing only power, water, and CO2 free purge gas. The OAAM utilized two membrane processes to segregate organic acids from interfering ions. The organic acid concentration was then determined based upon the conductiometric signal. Separation of individual organic acids was accomplished using a chromatographic column. Alcohols are determined in a similar manner after conversion to organic acids by sequential biocatalytic and catalytic oxidation steps. The OAAM was designed to allow the early diagnosis of under performing or failing sub-systems within the Water Recovery System (WRS) baselined for the International Space Station (ISS). To achieve this goal, several new technologies were developed over the course of the OAAM program.

Akse, James R.↗
DOE OSTI2021

Electrolyte compositions for stabilizing silicon electrodes in lithium batteries

A lithium-ion electrochemical cell comprises a first electrode, a second electrode comprising elemental silicon, a microporous separator membrane between the first and second electrodes, and an electrolyte in contact with the electrodes and the membrane. The electrolyte comprises a lithium salt at a concentration in the range of about 0.1 M to about 5 M, and an additional metal salt at a concentration in the range of about 0.001 to about 5 M dissolved in an organic solvent. The additional metal salt comprises a metal cation that can form a lithium-silicon-metal Zintl phase; and the first electrode comprises metallic lithium or a cathode active material capable of donating and accepting lithium ions to and from the second electrode during electrochemical cycling. Electrolytes for use with silicon-containing electrodes also are described.

Vaughey, John T.↗
DOE OSTI2025

Ligand‐Directed Actinide Oxo‐Bond Manipulation in Actinyl Thiacalix[4]arene Complexes

Abstract Understanding the chemistry of the inert actinide oxo bond in actinyl ions AnO 2 2+ is important for controlling actinide behavior in the environment, during separations, and in nuclear waste (An=U, Np, Pu). The thioether calixarene TC4A (4‐ tert ‐butyltetrathiacalix[4]arene) binds equatorially to the actinyl cation forming a conical pocket that differentiates the two trans‐ oxo groups. The ‘ate’ complexes, [A] 2 [UO 2 (TC4A)] (A=[Li(DME) 2 ], HNEt 3 ) and [HNEt 3 ] 2 [AnO 2 (TC4A)] (An=U, Np, Pu), enable selective oxo chemistry. Silylation of the U VI oxo groups by bis(trimethylsilyl)pyrazine occurs first at only the unencapsulated exo oxo and only one silylation is needed to enable migration of the endo oxo out of the cone, whereupon a second silylation affords the stable U IV cis‐ bis(siloxide) [A] 2 [U(OSiMe 3 ) 2 (TC4A)]. Calculations confirm that only one silylation event is needed to initiate oxo rearrangement, and that the putative cis dioxo isomer of [UO 2 (TC4A)] 2− would be stable if it could be accessed synthetically, at only 23 kcal.mol −1 in energy above the classical trans dioxo. Calculations for the transuranic cis [AnO 2 (TC4A)] 2− (An=Np, Pu) are at higher energies, 30–35 kcal.mol −1 , retaining the U complexes as the more obvious target for a cis ‐dioxo actinyl ion. The aryloxide (OAr) groups of the macrocycle are essential in stabilizing this as‐yet unseen uranyl geometry as further bonding in the TC4A U‐O Ar groups stabilizes the U=O ‘yl’ bonds, explaining the stability of the putative cis [UO 2 (TC4A)] 2− in this ligand framework.

Pyrch, Mikaela M. [College of Chemistry University↗
DOE OSTI2025

What is the Role of Relative Humidity on Conductivity in Polymer Electrolytes?

Ion transport properties in polymer electrolytes have been widely studied under rigorously dry and highly water-swollen conditions. However, the transition between these extremes, i.e., the low hydration regime, is still poorly understood at the molecular level and relevant to applications ranging from battery electrolytes to electrophoretic separations. Here, in this study, we apply atomistic molecular dynamics simulations to probe the role of hydration on ion mobilities and conductivities in LiTFSI-doped polyethers at low water content (less than 10% water by volume), which corresponds to 0−80% relative humidity conditions. With increasing water content, Li + ions exhibit two distinct regimes in their mobilities. At low water content, the majority of the Li + ions are weakly hydrated (two or fewer water molecules per Li + ion), maintaining strong interactions with their polymer solvation cage, and therefore exhibit only a weak increase in mobility relative to dry conditions. As water content increases, Li + ions form complete hydration shells, residing within water-rich domains that promote faster mobilities. Further, Li + mobilities increase more significantly in polymer electrolytes composed of more hydrophilic polymers and higher salt concentrations due to the formation of larger water-rich domains. In contrast, TFSI − has comparatively weak interactions with both the polymer and water, exhibiting a monotonic increase in mobility as a function of water content. Overall, these results help clarify the molecular mechanisms underlying ionic mobilities and conductivities in polymer electrolytes at low water content.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Beyond the acceptance limit of DRAGON: The case of the 6 Li(α,γ) 10 B reaction

Radiative capture reactions play a pivotal role for our understanding of the origin of the elements in the cosmos. Recoil separators provide an effective way to study these reactions, in inverse kinematics, and take advantage of the use of radioactive ion beams. However, a limiting factor in the study of radiative capture reactions in inverse kinematics is the momentum spread of the product nuclei, which can result in an angular spread larger than the geometric acceptance of the separator. The DRAGON facility at TRIUMF is a versatile recoil separator, designed to study radiative capture reactions relevant to astrophysics in the A~10–30 region. In this work we present the first attempt to study with DRAGON a reaction, 6 Li(α, γ) 10 B, for which the recoil angular spread exceeds DRAGON’s acceptance. Furthermore, our result is in good agreement with the literature value, showing that DRAGON can measure resonance strengths of astrophysically important reactions even when not all the recoils enter the separator.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗