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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 55 records · Page 3
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Blood Plasma Self-Separation Technologies during the Self-Driven Flow in Microfluidic Platforms

Blood plasma is the most commonly used biofluid in disease diagnostic and biomedical analysis due to it contains various biomarkers. The majority of the blood plasma separation is still handled with centrifugation, which is off-chip and time-consuming. Therefore, in the Lab-on-a-chip (LOC) field, an effective microfluidic blood plasma separation platform attracts researchers’ attention globally. Blood plasma self-separation technologies are usually divided into two categories: active self-separation and passive self-separation. Passive self-separation technologies, in contrast with active self-separation, only rely on microchannel geometry, microfluidic phenomena and hydrodynamic forces. Passive self-separation devices are driven by the capillary flow, which is generated due to the characteristics of the surface of the channel and its interaction with the fluid. Comparing to the active plasma separation techniques, passive plasma separation methods are more considered in the microfluidic platform, owing to their ease of fabrication, portable, user-friendly features. We propose an extensive review of mechanisms of passive self-separation technologies and enumerate some experimental details and devices to exploit these effects. The performances, limitations and challenges of these technologies and devices are also compared and discussed.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1996

Development of a Technique for Separating Raman Scattering Signals from Background Emission with Single-Shot Measurement Potential

Raman scattering is a powerful technique for quantitatively probing high temperature and high speed flows. However, this technique has typically been limited to clean hydrogen flames because of the broadband fluorescence interference which occurs in hydrocarbon flames. Fluorescence can also interfere with the Raman signal in clean hydrogen flames when broadband UV lasers are used as the scattering source. A solution to this problem has been demonstrated. The solution to the fluorescence interference lies in the fact that the vibrational Q-branch Raman signal is highly polarized for 90 deg. signal collection and the fluorescence background is essentially unpolarized. Two basic schemes are available for separating the Raman from the background. One scheme involves using a polarized laser and collecting a signal with both horizontal and vertical laser polarizations separately. The signal with the vertical polarization will contain both the Raman and the fluorescence while the signal with the horizontal polarization will contain only the fluorescence. The second scheme involves polarization discrimination on the collection side of the optical setup. For vertical laser polarization, the scattered Q-branch Raman signal will be vertically polarized; hence the two polarizations can be collected separately and the difference between the two is the Raman signal. This approach has been used for the work found herein and has the advantage of allowing the data to be collected from the same laser shot(s). This makes it possible to collect quantitative Raman data with single shot resolution in conditions where interference cannot otherwise be eliminated.

Hartfield, Roy↗
NASA NTRS2004

Computational Methods for Dynamic Stability and Control Derivatives

Force and moment measurements from an F-16XL during forced pitch oscillation tests result in dynamic stability derivatives, which are measured in combinations. Initial computational simulations of the motions and combined derivatives are attempted via a low-order, time-dependent panel method computational fluid dynamics code. The code dynamics are shown to be highly questionable for this application and the chosen configuration. However, three methods to computationally separate such combined dynamic stability derivatives are proposed. One of the separation techniques is demonstrated on the measured forced pitch oscillation data. Extensions of the separation techniques to yawing and rolling motions are discussed. In addition, the possibility of considering the angles of attack and sideslip state vector elements as distributed quantities, rather than point quantities, is introduced.

Green, Lawrence L.↗
NASA NTRS2003

Computational Methods for Dynamic Stability and Control Derivatives

Force and moment measurements from an F-16XL during forced pitch oscillation tests result in dynamic stability derivatives, which are measured in combinations. Initial computational simulations of the motions and combined derivatives are attempted via a low-order, time-dependent panel method computational fluid dynamics code. The code dynamics are shown to be highly questionable for this application and the chosen configuration. However, three methods to computationally separate such combined dynamic stability derivatives are proposed. One of the separation techniques is demonstrated on the measured forced pitch oscillation data. Extensions of the separation techniques to yawing and rolling motions are discussed. In addition, the possibility of considering the angles of attack and sideslip state vector elements as distributed quantities, rather than point quantities, is introduced.

Green, Lawrence L.↗
NASA NTRS1978

A new boundary-layer interaction techniques for separated flows

A new viscous-inviscid interation procedure is presented which is applicable to separated flows. The new procedure is simple, converges rapidly, and does not require numerical smoothing and underrelaxation at least in the cases computer thus far. Calculations are presented for the low-speed separated flow in the juncture region between an axisymmetric body and ting. The viscous computation is done with an inverse boundary-layer procedure which was previously developed. The inviscid computation is made with an axisymmetric transonic code called RAXBOD. The main advantage of the new interaction procedure is that it combines an inverse boundary-layer technique, which is applicable to separated flows, with an existing inviscid analysis code with only a slight boundary condition change required in the inviscid code.

Carter, J. E.↗
DOE OSTI2022

Ion Separations Based on Spontaneously Arising Streaming Potentials in Rotating Isoporous Membranes

Highly selective ion separations are vital for producing pure salts, and membrane-based separations are promising alternatives to conventional ion-separation techniques. Our previous work demonstrated that simple pressure-driven flow through negatively charged isoporous membranes can separate Li+ and K+ with selectivities as high as 70 in dilute solutions. The separation mechanism relies on spontaneously arising streaming potentials that induce electromigration, which opposes advection and separates cations based on differences in their electrophoretic mobilities. Although the separation technique is simple, this work shows that high selectivities are possible only with careful consideration of experimental conditions including transmembrane pressure, solution ionic strength, the K+/Li+ ratio in the feed, and the extent of concentration polarization. Separations conducted with a rotating membrane show Li+/K+ selectivities as high as 150 with a 1000 rpm membrane rotation rate, but the selectivity decreases to 1.3 at 95 rpm. These results demonstrate the benefits and necessity of quantitative control of concentration polarization in highly selective separations. Increases in solution ionic strength or the K+/Li+ feed ratio can also decrease selectivities more than an order of magnitude.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS1976

Electrophoretic separator for purifying biologicals

This technique separates a single narrow zone of sample mixture in an electrolyte medium into many zones containing a single component of the mixture and electrolyte between them. Since the densities of the separated zones generally differ from that of the intervening medium, such systems are gravitationally unstable and stabilization is required. The various techniques for stabilization include using the capillary space provided by thin films, the interstices of solid material such as filter paper and a variety of gel-forming substances.

Source record↗
DOE OSTI2022

Exploring rapid chemical separations of Sc-47 produced from photonuclear reactions on natural vanadium targets

Scandium-47 ( 47 Sc) production via bremsstrahlung irradiation of natural vanadium targets offers significant advantages for producing high purity 47 Sc; this work evaluates several rapid dissolution and chemical separation techniques for recovering high purity 47 Sc from irradiated vanadium. Here, techniques developed are combined into a simple, gram-scale, semi-automated target processing system that enables 47 Sc recovery from irradiated vanadium targets with chemical yields as high as 93 ± 3% and 47 Sc/V separation factors of 6 ± 3 ·10 11 within 90 min total processing times. Future research into H 2 O 2 resistant separation techniques and their applicability for direct process coupling to chelation are recommended.

07 ISOTOPE AND RADIATION SOURCES↗
NASA NTRS1979

A new boundary-layer inviscid iteration technique for separated flow

A new viscous-inviscid iteration procedure is presented which is applicable to separated flows. The new procedure is simple, converges rapidly, and does not require numerical smoothing, at least in the cases computed thus far. Calculations are presented for both incompressible and compressible separated flow in the juncture region between an axisymmetric body and sting. The viscous computation is obtained with a recently developed inverse boundary-layer procedure which is no more complicated than a standard direct finite-difference boundary-layer technique. The inviscid computation is made with an axisymmetric transonic code called RAXBOD, in which surface injection is used to represent the viscous effects.

Carter, J. E.↗
NASA NTRS1990

Production of oxygen from lunar ilmenite

The following subjects are addressed: (1) the mechanism and kinetics of carbothermal reduction of simulated lunar ilmenite using carbon and, particularly, CO as reducing agents; (2) the determination of the rate-limiting steps; (3) the investigation of the effect of impurities, particularly magnesium; (4) the search for catalysts suitable for enhancement of the rate-limiting step; (5) the comparison of the kinetics of carbothermal reduction with those of hydrogen reduction; (6) the study of the combined use of CO and hydrogen as products of gasification of carbonaceous solids; (7) the development of reduction methods based on the use of waste carbonaceous compounds for the process; (8) the development of a carbothermal reaction path that utilizes gasification of carbonaceous solids to reducing gaseous species (hydrocarbons and carbon monoxide) to facilitate the reduction reaction kinetics and make the process more flexible in using various forms of carbonaceous feeds; (9) the development of advanced gas separation techniques, including the use of high-temperature ceramic membranes; (10) the development of an optimum process flow sheet for carbothermal reduction, and comparison of this process with the hydrogen reduction scheme, as well as a general comparison with other leading oxygen production schemes; and (11) the use of new and advanced material processing and separation techniques.

Zhao, Y.↗
NASA NTRS1989

Turbulent flow separation control through passive techniques

Several passive separation control techniques for controlling moderate two-dimensional turbulent flow separation over a backward-facing ramp are studied. Small transverse and swept grooves, passive porous surfaces, large longitudinal grooves, and vortex generators were among the techniques used. It was found that, unlike the transverse and longitudinal grooves of an equivalent size, the 45-deg swept-groove configurations tested tended to enhance separation.

Lin, J. C.↗
DOE OSTI2023

Sequential separation of battery electrode materials and metal foils in aqueous media

To recycle high-value lithium-ion battery components, it is imperative to efficiently separate electrode materials from current collector foils and to separate cathodes from anodes. This study investigates the delamination behaviors of cathodes and anodes from their respective current collectors in aqueous media. Whereas anode films can easily detach from copper foils in water, the delamination of cathode films does not exhibit the same behavior in water; instead, the cation exchange reaction results in lithium leaching and aluminum corrosion in the presence of water. Here, a buffer solution with surfactant additives has been designed to prevent aluminum corrosion and to improve solution wetting behavior, thereby facilitating cathode delamination. The delamination difference enables the sequential recovery of electrode materials and metal foils at different separation stages, simplifying the traditionally intricate processes within a one-pot recovery system. The recovered materials retain their crystal structure and morphology, and there are no signs of aluminum corrosion or residues on the metal foils. The sequential separation technique achieves nearly 100% separation efficiency for electrode materials from metal foils and over 98% separation efficiency for cathode and anode materials.

25 ENERGY STORAGE↗
DOE OSTI2021

Origins of Clustering of Metalate–Extractant Complexes in Liquid–Liquid Extraction

Effective and energy-efficient separation of precious and rare metals is very important for a variety of advanced technologies. Liquid-liquid extraction (LLE) is a relatively less energy intensive separation technique, widely used in separation of lanthanides, actinides, and platinum group metals (PGMs). In LLE, the distribution of an ion between an aqueous phase and an organic phase is determined by enthalpic (coordination interactions) and entropic (fluid reorganization) contributions. The molecular scale details of these contributions are not well understood. Preferential extraction of an ion from the aqueous phase is usually correlated with the resulting fluid organization in the organic phase, as the longer-range organization increases with metal loading. However, it is difficult to determine the extent to which organic phase fluid organization causes, or is caused by, metal loading. In this study, we demonstrate that two systems with the same metal loading may impart very different organic phase organizations and investigate the underlying molecular scale mechanism. Small-angle X-ray scattering shows that the structure of a quaternary ammonium extractant solution in toluene is affected differently by the extraction of two metalates (octahedral PtCl 6 2- and square-planar PtCl 6 2- ), although both are completely transferred into the organic phase. The aggregates formed by the metalate-extractant complexes (approximated as reverse micelles) exhibit a more long-range order (clustering) with PtCl 6 2- compared to that with PtCl 6 2- . Vibrational sum frequency generation spectroscopy and complementary atomistic molecular dynamics simulations on model Langmuir monolayers indicate that the two metalates affect the interfacial hydration structures differently. Furthermore, the interfacial hydration is correlated with water extraction into the organic phase. Overall, these results support a strong relationship between the organic phase organizational structure and the different local hydration present within the aggregates of metalate-extractant complexes, which is independent of metalate concentration.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Investigating Radiation-Induced Actinide Species in Solution

Used nuclear fuel (UNF) separation techniques that strive to separate radiotoxic americium (Am) from trivalent lanthanide fission products through oxidation state control have increased research efforts surrounding Am(V) and Am(VI). However, equivalent knowledge of the tetravalent state, Am(IV), has remained elusive, particularly in conditions more representative of UNF reprocessing, i.e., in concentrated nitric acid (HNO3). With this in mind, we have used electron pulse radiolysis to study the radiation-induced redox reaction of Am(III) with the oxidizing nitrate radical (NO3?) in 6 M HNO3: Am(III) + NO3? ? Am(IV) + NO3? . These experiments enabled us to observe the growth and decay of Am(IV) in a concentrated acidic solution for the first time. The transient Am(IV) species was found to have a lifetime of ~16 µs?sufficiently long-lived to play a critical mechanistic role in UNF reprocessing systems. Additionally, we performed the first-ever temperature-dependent kinetics study of an actinide element, elucidating unprecedented Arrhenius and Eyring activation parameters for the reaction of Am(III) with NO3?. This new knowledge provides much-needed molecular-level insights into the radiation-induced behavior of Am.

actinide↗
NASA NTRS2014

Initial Results from the Kwajalein Micrometeorite Collections

Micrometeorites are constantly arriving at the Earth's surface, however, they are quickly diluted by the natural and anthropogenic back-ground dust. The successful collection of micromete-orites requires either the employment of a separation technique (e.g. using magnets to separate metal-bearing micrometeorites from deepsea sediments [e.g. 1,2] and dissolved pre-historic limestones and salts [e.g. 3,4]), or an approach that limits contamination by terrestrial dust (e.g. collecting from ice, snow and well water in polar regions - locations where the terrestrial dust flux is so low that micrometeorites repre-sent the major dust component [e.g. 5-7]). We have recently set up a micrometeorite collection station on Kwajalein Island in the Republic of the Marshall Is-lands in the Pacific Ocean, using high volume air samplers to collect particles directly from the atmosphere. Collecting at this location exploits the considerably reduced anthropogenic background; Kwajalein is >1000 miles from the nearest continent and for much of the year, trade winds blow from the northeast at 15 to 20 knots providing a continuous stream of oceanic aerosol for sampling. By collecting directly from the atmosphere, the terrestrial age of the particles, and hence weathering they experience, is minimal. We therefore anticipate that the Kwajalein col-lection may include particles that are highly susceptible to weathering and either not preserved well or not found at all in other collections. In addition, this collection method allows for particle arrival times to be constrained so that collections can be timed to correlate with celestial events (e.g. meteor showers). Here we describe the collections and their preparation and report on the initial results.

Wozniakiewicz, P. J.↗
DOE OSTI2022

Machine Straightness Error Measurement Based on Optical Fiber Fabry–Pérot Interferometer Monitoring Technique

Abstract In this research, we propose an Error Separation Technique (EST) based on optical fiber sensors for on-machine straightness error measurement. Two fiber optic Fabry–Pérot interferometers have been developed serving as two displacement sensors. The displacement distance is computed according to the reflected spectrum from interferometers, which can achieve a sub-micrometer resolution. The two-point method has been employed to separate the straightness error of the slides and the profile error of a fine-polished standard block. The spacing distance between two interferometers is determined by the diameter of optical fibers so that the EST's resolution has the potential to reach the sub-millimeter scale. In the experiment, the straightness error has been measured on a commercially available computer numerical control machine tool, and the measurement has been conducted on its x-axis. The spacing distance between two optical fiber sensors is 1.5 mm which equals the EST's resolution along the machine tool's x-axis. The separated profile error of the measured standard block is around 30 µm which has been verified by a high precision Coordinate Measurement Machine (CMM). The magnitude of the separated straightness error is around 40 µm. This technique is flexible and simple to be conducted, which can contribute to the micro-machine tool calibration and other straightness error applications.

Engineering↗
NASA NTRS1990

Aerodynamic separation and glideback of a Mach 3 staged booster

A study has been conducted of the staging maneuver for a two-stage, vertical-takeoff, launch vehicle and the subsequent glideback of the booster to a launch site runway. The booster and orbiter are both winged, fully reusable, and have liquid rocket main propulsion. for the staging maneuver, which nominally occurs at Mach 3, a flight control system and separation technique were devised which produced successful separations over a wide range of staging angles of attack. A guidance algorithm was developed for the unpowered glide-back of the booster from the completion of the staging maneuver to touchdown on a runway in the vicinity of the launch site. Using this guidance technique, the booster successfully touched down on the runway while being subjected to a wide range of seasonal and perturbed atmospheric conditions with and without wids as well as errors in staging state conditions and errors in predicted aerodynamics.

Naftel, J. C.↗