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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 217 records · Page 12
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Amine functionalized supported ionic liquid membranes (SILMs) for CO 2 /N 2 separation

Supported ionic liquid membranes (SILMs), containing aprotic N-heterocyclic anion ionic liquids (AHA ILs) in an inorganic inert support, exhibit CO 2 /N 2 permselectivity values as high as 640 at 35.0 °C and 0.03 bar CO 2 , which represents conditions similar to post-combustion carbon capture (PCCC) from a natural gas power plant. A Fickian model fit to the experimental data estimates CO 2 permeability at direct air capture (DAC) conditions of 10,400 barrer and a CO 2 /N 2 permselectivity of 4000 for the best performing IL, triethyl(octyl)phosphonium 4-bromopyrazolide ([P 2228 ][4-BrPyra]). The most important criterion for high selectivity is a large equilibrium constant for binding between the IL and CO 2 , which results in high CO 2 solubility. ILs with smaller molar volumes and with no fluoroalkyl chains enhance N 2 rejection. As a result, low viscosity and high IL molar density also enhance CO 2 /N 2 permselectivity and CO 2 permeance.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRSDate not supplied

Meteorite Ablation at the HYMETS ARC-JET Facility

One of the primary goals of the Asteroid Threat Assessment Program (ATAP) is to understand the ablation phenomena of meteors (e.g., spallation, evaporation, melt flow, etc.). Therefore, a test campaign was executed at the Hypersonic Material Test System (HYMETS) facility on samples of an ordinary chondrite (e.g., Tamdakht) and samples of basalt from the Columbia plateau. High melt viscosities and low ablation rates are predicted for basalt due to higher concentrations of silica and alumina in the matrix phase. However, high-speed video and post-test analysis reveal that basalt experiences greater rates of ablation than Tamdakht. Post-test analysis of emission spectra reveals the presence of volatile species that may explain the discrepancy between model predictions and observed phenomena.

Meteor↗
NASA NTRS1988

Novel polyamide-imines

An account is given of tough, thermally stable linear polyimides containing amide linkages that recommend themselves for use in high temperature-resistant films and coatings as well as matrix resins for graphite-reinforced structures. Four such polymers were synthesized from unsubstituted amide diamines, and two others from N-substituted amide diamines. High inherent viscosities and glass transition temperatures were obtained. The films exhibit good resistance to organic solvents. Films of the 4,4-prime-isomer polyamide-imide yielded exceptionally high modulus and toughness during impact evaluation.

Dezern, James F.↗
DOE OSTI2025

Low viscosity of solid MgO at high pressures and strain rates measured using the laser-driven Richtmyer-Meshkov instability

Solids are often assumed to behave as viscous fluids under high-strain rates. This behavior has been studied experimentally in metals but largely unexplored in brittle ceramic materials. Here, in this study, we present a technique for measuring the viscosity of MgO using time-resolved velocimetry to track the growth rate of a perturbation caused by the Richtmyer-Meshkov instability at the OMEGA EP laser facility. To interpret the results, we use an in-house Eulerian hydrocode to simulate our experiments and model the plastic deformation of solid MgO as a viscous fluid. Results indicate that MgO has a surprisingly low upper bound to its effective viscosity of ∼10 2 ⁢ Pa s at 175 ± 15⁢ GPa, ∼3500⁢K, and 10 6 −10 7 s −1 strain rate.

Perez, Tyler M. [Johns Hopkins Univ., Baltimore, M↗
NASA NTRS2014

Electrolyte Suitable for Use in a Lithium Ion Cell or Battery

Electrolyte suitable for use in a lithium ion cell or battery. According to one embodiment, the electrolyte includes a fluorinated lithium ion salt and a solvent system that solvates lithium ions and that yields a high dielectric constant, a low viscosity and a high flashpoint. In one embodiment, the solvent system includes a mixture of an aprotic lithium ion solvating solvent and an aprotic fluorinated solvent.

McDonald, Robert C.↗
NASA NTRS1988

Directional solidification of Al-Ni/SiC composites during parabolic trajectories

Aluminum-6.1 wt. pct. nickel-silicon carbide composites containing varying volume fractions and particle sizes of SiC were directionally solidified at different translation rates and temperature gradients, under variable gravity levels. High-gravity, high-volume fractions of particles or high effective viscosity of liquid favored the engulfment of particles by the melt interface. Solidification under low gravity seemed to deflocculate the SiC particle agglomerates, while opposite results were obtained when solidifying under high gravity. Intercellular spacings were higher under low gravity solidfication.

Dhindaw, B. K.↗
NASA NTRS2018

Faraday Forcing of High-Temperature Levitated Liquid Metal Drops for the Measurement of Surface Tension

In this work, a method for the measurement of surface tension using continuous periodic forcing is presented. To reduce gravitational effects, samples are electrostatically levitated prior to forcing. The method, called Faraday forcing, is particularly well suited for fluids that require high temperature measurements such as liquid metals where conventional surface tension measurement methods are not possible. It offers distinct advantages over the conventional pulse-decay analysis method when the sample viscosity is high or the levitation feedback control system is noisy. In the current method, levitated drops are continuously translated about a mean position at a small, constant forcing amplitude over a range of frequencies. At a particular frequency in this range, the drop suddenly enters a state of resonance, which is confirmed by large executions of prolate/oblate deformations about the mean spherical shape. The arrival at this resonant condition is a signature that the parametric forcing frequency is equal to the drop’s natural frequency, the latter being a known function of surface tension. A description of the experimental procedure is presented. A proof of concept is given using pure Zr and a Ti(sub 39.5)Zr(sub 39.5)Ni(sub 21) alloy as examples. The results compare favorably with accepted literature values obtained using the pulse-decay method.

Nevin Brosius↗
DOE OSTI2022

Stomatal conductance, not biochemistry, drives low temperature acclimation of photosynthesis in Populus balsamifera , regardless of nitrogen availability

Low temperature thermal acclimation may require adjustments to nitrogen and water use to sustain photosynthesis due to slow enzyme functioning and high-water viscosity. However, understanding of photosynthetic acclimation to temperatures below 11°C is limited. Here, we acclimated Populus balsamifera to 6 °C and 10 °C (6A and 10A, respectively) and provided the trees with either high or low N fertilizer. We measured net CO 2 assimilation rates (A net ), stomatal conductance (g s ), maximum rates of Rubisco carboxylation (V cmax ) and electron transport (J max ), and dark respiration (R d ) at leaf temperatures of 2, 6, 10, 14 and 18 °C, along with leaf N concentrations. The 10A trees had higher A net than the 6A trees at warmer leaf temperatures, which was correlated with higher g s in the 10A trees. The instantaneous temperature responses of V cmax , J max and R d were similar for trees from both acclimation temperatures. While soil N availability increased leaf N concentrations, this had no effect on acclimation of photosynthesis or respiration. Our results indicate that acclimation below 11°C occurred primarily through changes in stomatal conductance, not photosynthetic biochemistry, and was unaffected by short-term N supply. Thermal acclimation of stomatal conductance should therefore be a priority for future carbon cycle model development.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1984

The effect of viscosity on impact cratering and possible application to the icy satellites of Saturn and Jupiter

Impact experiments in Newtonian fluids with a range of viscosities of 0.001 to 60 Pa s demonstrate that transient crater volume and shape depend on target viscosity as well as on gravity. Volume is reduced, and depth-to-diameter ratio is increased for cratering events in which viscosity plays a dominant role. In addition to being affected by target kinematic viscosity, viscous scaling is most strongly influenced by projectile diameter, less strongly by projectile velocity, and least strongly by gravity. In a planetary context, viscous effects can occur for craters formed by small or slow moving impacting bodies, low planetary surface densities, high surface viscosities, and low gravity values; conditions all likely for certain impacts into the icy satellites of Saturn and Jupiter, especially if liquid mantles were still present beneath solid crusts. Age dating based on crater counts and size-frequency distributions for these icy bodies may have to be modified to account for the possibility that viscosity-dominated craters were initially smaller and deeper than their gravity-controlled counterparts.

Fink, J.↗
NASA NTRS2016

Water in the Cratonic Mantle Lithosphere

The fact that Archean and Proterozoic cratons are underlain by the thickest (>200 km) lithosphere on Earth has always puzzled scientists because the dynamic convection of the surrounding asthenosphere would be expected to delaminate and erode these mantle lithospheric "keels" over time. Although density and temperature of the cratonic lithosphere certainly play a role in its strength and longevity, the role of water has only been recently addressed with data on actual mantle samples. Water in mantle lithologies (primarily peridotites and pyroxenites) is mainly stored in nominally anhydrous minerals (olivine, pyroxene, garnet) where it is incorporated as hydrogen bonded to structural oxygen in lattice defects. The property of hydrolytic weakening of olivine [4] has generated the hypothesis that olivine, the main mineral of the upper mantle, may be dehydrated in cratonic mantle lithospheres, contributing to its strength. This presentation will review the distribution of water concentrations in four cratonic lithospheres. The distribution of water contents in olivine from peridotite xenoliths found in kimberlites is different in each craton (Figure 1). The range of water contents of olivine, pyroxene and garnet at each xenolith location appears linked to local metasomatic events, some of which occurred later then the Archean and Proterozoic when these peridotites initially formed via melting. Although the low olivine water contents (<10 ppm wt H2O) at > 6 GPa at the base of the Kaapvaal cratonic lithosphere may contribute to its strength, and prevent its delamination, the wide range of those from Siberian xenoliths is not compatible with providing a high enough viscosity contrast with the asthenophere. The water content in olivine inclusions from Siberian diamonds, on the other hand, have systematically low water contents (<20 ppm wt H2O). The xenoliths may represent a biased sample of the cratonic lithosphere with an over-­abundance of metasomatized peridotites with high water contents. The olivine inclusions, however, may have been protected from metasomatism by their host diamond and record the overall low olivine water content of the cratonic lithosphere. Water may thus still play a role in cratonic keel longevity.

Peslier, A. H.↗
NASA NTRS2003

High-Pressure Transport Properties Of Fluids: Theory And Data From Levitated Drops At Combustion-Relevant Temperatures

Although the high pressure multicomponent fluid conservation equations have already been derived and approximately validated for binary mixtures by this PI, the validation of the multicomponent theory is hampered by the lack of existing mixing rules for property calculations. Classical gas dynamics theory can provide property mixing-rules at low pressures exclusively. While thermal conductivity and viscosity high-pressure mixing rules have been documented in the literature, there is no such equivalent for the diffusion coefficients and the thermal diffusion factors. The primary goal of this investigation is to extend the low pressure mixing rule theory to high pressures and validate the new theory with experimental data from levitated single drops. The two properties that will be addressed are the diffusion coefficients and the thermal diffusion factors. To validate/determine the property calculations, ground-based experiments from levitated drops are being conducted.

Bellan, Josette↗
NASA NTRS2006

Viscosity Measurement for Tellurium Melt

The viscosity of high temperature Te melt was measured using a new technique in which a rotating magnetic field was applied to the melt sealed in a suspended ampoule, and the torque exerted by rotating melt flow on the ampoule wall was measured. Governing equations for the coupled melt flow and ampoule torsional oscillation were solved, and the viscosity was extracted from the experimental data by numerical fitting. The computational result showed good agreement with experimental data. The melt velocity transient initiated by the rotating magnetic field reached a stable condition quickly, allowing the viscosity and electrical conductivity of the melt to be determined in a short period.

Lin, Bochuan↗
DOE OSTI2020

Experimental determination of the temperature-dependent Van Hove function in a Zr 80 Pt 20 liquid

Even though the viscosity is one of the most fundamental properties of liquids, the connection with the atomic structure of the liquid has proven elusive. By combining inelastic neutron scattering with the electrostatic levitation technique, the time-dependent pair-distribution function (i.e., the Van Hove function) has been determined for liquid Zr 80 Pt 20 . We show that the decay time of the first peak of the Van Hove function is directly related to the Maxwell relaxation time of the liquid, which is proportional to the shear viscosity. This result demonstrates that the local dynamics for increasing or decreasing the coordination number of local clusters by one determines the viscosity at high temperature, supporting earlier predictions from molecular dynamics simulations.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1941

Damping characteristics of dashpots

An investigation of the damping characteristics of dashpots was carried out combining theory and experiment. Laminar flow was assumed and three equations for the steady velocity of a piston moving in a cylinder filled with liquid were derived. In the first equation, the piston was assumed coaxial in the cylinder and, in the second equation, the piston was assumed eccentric in the cylinder with an element of the piston in contact with the cylinder wall. The third equation is for a piston of circular cross section in an elliptical cylinder. Experiments showed that the piston is normally eccentric in the cylinder. The pistons tested were 1.25 and 2 inches in diameter 0.062 to 1.00 inch long, and the clearances varied from 1.36 to 5.16 x 10 to the 3rd power inch. The difference in pressure on the two sides of the piston varied from about 2 to 55 pounds per square inch. The piston velocities for each assembly were measured with damping liquids of three different viscosities. At high piston velocities, when turbulent flow exists, the observed velocities were much lower than the velocities calculated on the basis of laminar flow. Results for a wide range of Reynolds numbers are presented in graphical form.

INSTRUMENTS-MICROMETERS↗
NASA NTRS1988

Polyenamines from aromatic diacetylenic diketones and diamines

The synthesis and characterization of several ployenamine ketones are discussed wherein conjugated diacetylenic diketones and aromatic diamines are used as a route to the formation of high molecular weight polyenamine ketones which exhibit good mechanical properties and can be cast into creasible films. Typical polymerization conditions involved the reaction of stoichiometric amounts of 1,4- or 1,3-PPPO and a diamine at 60°-130° C. in m-cresol at (w/w) solids content of 8-26% for a specified period of time under a nitrogen atmosphere. Novel polyenamine ketones were prepared with inherent viscosities as high as 1.99 dl/g and tough, clear amber films with tensile strengths of 12,400 psi and tensile moduli of 397,000 psi were cast from solutions of the polymers in chloroform. The polymers exhibited T g s as high as 235° C. and weight losses of 14% after aging at 232° C. in circulating air for sixty hours. The specific conditions for the preparation of the various polyenamine ketones are presented in Table I. In most cases, the elemental analyses for the polyenamine ketones, shown in Table II, agree within ±0.3% of the theoretical values.

Paul M Hergenrother↗
DOE OSTI2025

Rippled shock propagation in a laser-driven target at multimegabar pressures

The evolution of non-uniform shocks produced by modulated laser irradiation or surface perturbations is relevant to studies of inertial confinement fusion and material properties at high-energy-density conditions. We present results from an experiment conducted at the OMEGA EP laser facility, where a 300 GPa shock was driven into a fused silica sample with pre-fabricated single-mode surface modulations. Using time-resolved optical velocimetry, we captured the continuous evolution of rippled shock motion, enabling a comprehensive mapping of the spatial amplitude history from formation to phase reversal in a single experiment. Initially, the ablation-driven shock inherits a fraction of the surface modulation amplitude from the sample, which subsequently grows before decaying, ultimately leading to the flattening of the rippled shock and a phase reversal. We find that two-dimensional inviscid hydrodynamic simulation of the experiment is able to qualitatively capture many aspects of the rippled shock evolution but over-predicts the initial amplitude growth. This experimental platform, capable of accommodating varying ripple wavelengths, lays the groundwork for a potential viscometry method at extreme pressures, where viscous effects manifest as differences in shock flattening times between rippled shocks of two distinct wavelengths propagating through the sample.

36 MATERIALS SCIENCE↗
NASA NTRS1987

Polyenamines from aromatic diacetylenic diketones and diamines

The synthesis and characterization of several polyenamine ketones are discussed wherein conjugated diacetylenic diketones and aromatic diamines are used as a route to the formation of high molecular weight polyenamine ketones which exhibit good mechanical properties and can be cast into creasible films. Typical polymerization conditions involved the reaction of stoichiometric amounts of 1,4- or 1,3-PPPO and a diamine at 60 to 130 C in m-cresol at (w/w) solids content of 8 to 26% for a specified period of time under a nitrogen atmosphere. Novel polyenamine ketones were prepared with inherent viscosities as high as 1.99 dl/g and tough, clear amber films with tensile strengths of 12,400 psi and tensile moduli of 397,000 psi were cast from solutions of the polymers in chloroform. In most cases, the elemental analyses for the polyenamine ketones agree within + or - 0.3% of the theoretical values.

Hergenrother, Paul M.↗