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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 1,135 records · Page 63
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

Source of Scatter in the Creep Lives of NiAl(Hf) Single Crystals Revealed

In recent years, there has been an increased emphasis in developing NiAl-based alloys for high- temperature applications in aircraft engines. In comparison to commercial superalloys, binary NiAl has a higher melting temperature, lower density, larger thermal conductivity, and better oxidation resistance. These properties make it a desirable material to replace superalloys as blades and vanes in aircraft engines. Despite this attractive combination of properties, binary NiAl cannot be used as a reliable structural material because of its low-temperature brittleness and poor high-temperature creep strength. GE Aircraft Engines in Cincinnati, Ohio, has recently developed NiAl(Hf) alloys that have creep strengths comparable to commercial superalloys while maintaining the other desirable properties of binary NiAl. The microstructures of these alloys consist of finely distributed G-phase (Ni_(16)Hf_(6)Si_(7)) precipitates, which strengthen the NiAl matrix. However, while the creep properties of these alloys were being evaluated, considerable scatter was observed in the creep lives of specimens tested under identical stress and temperature conditions. Although these alloys had nominally the same composition, the test specimens were obtained from four different ingots (A, B, C, and D) that had been heat treated under similar conditions. The NASA Lewis Research Center began the present study at the request of GE Aircraft Engines under a Space Act Agreement to identify the source of this scatter.

Source record↗
NASA NTRS2007

High-Performance, Radiation-Hardened Electronics for Space Environments

The Radiation Hardened Electronics for Space Environments (RHESE) project endeavors to advance the current state-of-the-art in high-performance, radiation-hardened electronics and processors, ensuring successful performance of space systems required to operate within extreme radiation and temperature environments. Because RHESE is a project within the Exploration Technology Development Program (ETDP), RHESE's primary customers will be the human and robotic missions being developed by NASA's Exploration Systems Mission Directorate (ESMD) in partial fulfillment of the Vision for Space Exploration. Benefits are also anticipated for NASA's science missions to planetary and deep-space destinations. As a technology development effort, RHESE provides a broad-scoped, full spectrum of approaches to environmentally harden space electronics, including new materials, advanced design processes, reconfigurable hardware techniques, and software modeling of the radiation environment. The RHESE sub-project tasks are: SelfReconfigurable Electronics for Extreme Environments, Radiation Effects Predictive Modeling, Radiation Hardened Memory, Single Event Effects (SEE) Immune Reconfigurable Field Programmable Gate Array (FPGA) (SIRF), Radiation Hardening by Software, Radiation Hardened High Performance Processors (HPP), Reconfigurable Computing, Low Temperature Tolerant MEMS by Design, and Silicon-Germanium (SiGe) Integrated Electronics for Extreme Environments. These nine sub-project tasks are managed by technical leads as located across five different NASA field centers, including Ames Research Center, Goddard Space Flight Center, the Jet Propulsion Laboratory, Langley Research Center, and Marshall Space Flight Center. The overall RHESE integrated project management responsibility resides with NASA's Marshall Space Flight Center (MSFC). Initial technology development emphasis within RHESE focuses on the hardening of Field Programmable Gate Arrays (FPGA)s and Field Programmable Analog Arrays (FPAA)s for use in reconfigurable architectures. As these component/chip level technologies mature, the RHESE project emphasis shifts to focus on efforts encompassing total processor hardening techniques and board-level electronic reconfiguration techniques featuring spare and interface modularity. This phased approach to distributing emphasis between technology developments provides hardened FPGA/FPAAs for early mission infusion, then migrates to hardened, board-level, high speed processors with associated memory elements and high density storage for the longer duration missions encountered for Lunar Outpost and Mars Exploration occurring later in the Constellation schedule.

Keys, Andrew S.↗
NASA NTRS2011

Kinetic Simulation and Energetic Neutral Atom Imaging of the Magnetosphere

Advanced simulation tools and measurement techniques have been developed to study the dynamic magnetosphere and its response to drivers in the solar wind. The Comprehensive Ring Current Model (CRCM) is a kinetic code that solves the 3D distribution in space, energy and pitch-angle information of energetic ions and electrons. Energetic Neutral Atom (ENA) imagers have been carried in past and current satellite missions. Global morphology of energetic ions were revealed by the observed ENA images. We have combined simulation and ENA analysis techniques to study the development of ring current ions during magnetic storms and substorms. We identify the timing and location of particle injection and loss. We examine the evolution of ion energy and pitch-angle distribution during different phases of a storm. In this talk we will discuss the findings from our ring current studies and how our simulation and ENA analysis tools can be applied to the upcoming TRIO-CINAMA mission.

Fok, Mei-Ching H.↗
NASA NTRS2014

Coordinated Chemical and Isotopic Imaging of Bells (CM2) Meteorite Matrix

Meteoritic organic matter is a complex conglomeration of species formed in distinct environments and processes in circumstellar space, the interstellar medium, the Solar Nebula and asteroids. Consequently meteorites constitute a unique record of primordial organic chemical evolution. While bulk chemical analysis has provided a detailed description of the range and diversity of organic species present in carbonaceous chondrites, there is little information as to how these species are spatially distributed and their relationship to the host mineral matrix. The distribution of organic phases is nevertheless critical to understanding parent body processes. The CM and CI chondrites all display evidence of low temperature (< 350K) aqueous alteration that may have led to aqueous geochromatographic separation of organics and synthesis of new organics coupled to aqueous mineral alteration. Here we present the results of the first coordinated in situ isotopic and chemical mapping study of the Bells meteorite using a newly developed two-step laser mass spectrometer (mu-L(sup 2)MS) capable of measuring a broad range of organic compounds.

Clemett, S. J.↗
NASA NTRSDate not supplied

Accelerating SNP Development with Radiation Source Approximations for Far-Field Environment Modeling

The successful development and deployment of space nuclear power and propulsion technology requires a high-fidelity, efficient means of modeling ex-core radiation fields. Monte Carlo particle transport codes provide enable the highest level of fidelity in radiation field modeling but are inefficient for modeling ex-core radiation without modification. This paper details the development of an approach to ex-core radiation field modeling that maintains the fidelity of a Monte Carlo transport approach without sacrificing computational efficiency. This approach is based on recent improvements to an existing Monte Carlo transport acceleration technique known as surface source banking. As the transport of many particles is required to ensure adequate uncertainty in far field transport, analytical reconstruction techniques are employed to represent surface source banks as sampleable series of distributions in particle phase from which an arbitrarily large number of particles can be generated and simulated. All steps of this approach are incorporated into an AMA model to test both the underlying mathematics of the analytical source reconstruction process, as well as the relevance of the technique as a whole towards SNP applications. These tests demonstrated that this approach is capable of accelerating far-field radiation modeling in SNP-relevant scenarios by factors of at least nine over purely eigenvalue-based scenarios without significantly sacrificing simulation accuracy.

Surface Source Banking↗
DOE OSTI2014

Sensing the wavefront of x-ray free-electron lasers using aerosol spheres

Characterizing intense, focused x-ray free electron laser (FEL) pulses is crucial for their use in diffractive imaging. We describe how the distribution of average phase tilts and intensities on hard x-ray pulses with peak intensities of 10 21 W/m 2 can be retrieved from an ensemble of diffraction patterns produced by 70 nm-radius polystyrene spheres, in a manner that mimics wave-front sensors. Besides showing that an adaptive geometric correction may be necessary for diffraction data from randomly injected sample sources, the paper demonstrates the possibility of collecting statistics on structured pulses using only the diffraction patterns they generate and highlights the imperative to study its impact on single-particle diffractive imaging.

43 PARTICLE ACCELERATORS↗
DOE OSTI2014

Development and Testing of an Americium/Lanthanide Separation Flowsheet Using Sodium Bismuthate

The separation of Am from the lanthanides and curium is a key step in proposed advanced fuel cycle scenarios. The partitioning and transmutation of Am is desirable to minimize the long-term heat load of material interred in a future high-level waste repository. A separation process amenable to process scale-up remains elusive. Given only subtle chemistry differences within and between the ions of the trivalent actinide and lanthanide series this separation is challenging ; however, higher oxidation states of americium can be prepared using sodium bismuthate and separated via solvent extraction using diamylamylphosphonate (DAAP) extraction. Among the other trivalent metals only Ce is also oxidized and extracted. Due to the long-term instability of Am(VI) , the loaded organic phase is readily selectively stripped to partition the actinide to a new acidic aqueous phase. Batch extraction distribution ratio measurements were used to design a flowsheet to accomplish this separation. Additionally, crossflow filtration was investigated as a method to filter the bismuthate solids from the feed solution prior to extraction. Results of the filtration studies, flowsheet development work and flowsheet performance testing using a centrifugal contactor are detailed.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2018

MICRO-CELLULOSE FIBER REINFORCED BIOCOMPOSITES FOR ADDITIVE MANUFACTURING

Polymer additive manufacturing (AM) technology is rapidly growing and it is transitioning from being primarily a prototyping method to an advanced manufacturing technique. Melt extrusion/fused deposition modeling, a method in which molten thermoplastic-based feedstock material is deposited in a raster pattern layer by layer, is the most commonly used technique in polymer AM. The technique enables direct digital manufacturing of desired geometry with controlled anisotropic distribution of reinforcing phase. While thermoplastic composites are being used in many areas of industry including AM, due to increasing environmental and long-term sustainability concerns, there is an increasing interest in bio-based renewable alternatives. Nano-to-mm scale plant-based fibers are utilized to improve properties of thermoplastics and produce bio-composites. The effect of commercially available micro-scale cellulose fibers (MFC) on the mechanical and rheological behavior of polylactic acid to produce fully bio-based composites are being investigated and selected formulations will be 3D-printed to investigate the effect of printing process on MFC alignment. Significant increases in both tensile strength and elastic modulus of compression-molded MFC-PLA composites were observed at 40 % (by wt) fiber levels.

Tekinalp, Halil↗
DOE OSTI2021

Dihadron beam spin asymmetries on an unpolarized hydrogen target with CLAS12

The semi-inclusive deep inelastic scattering process, where an electron scatters off a proton target at high enough energy that the process can be described by the scattering off a single constituent particle, offers targeted access to the internal structure of the nucleon. The process can be described in two phases by parton distribution functions (PDFs), which describe the likelihood of finding a quark or gluon in a particular state inside of the nucleon and then by fragmentation functions (FFs) which describe the likelihood of forming a particular final state particle.

Hayward, Timothy↗
DOE OSTI2013

Review of the Development and Testing of a New Family of Boron and Gadolinium-Bearing Dual Thermal Neutron Absorbing Alloys - 13026

The development of a new class of Fe-based thermal neutron absorbing alloys (patent pending) containing both natural boron (B) and gadolinium (Gd) is reviewed. Testing has shown that Ar and N inert gas atomized powder metallurgy (PM) variants offer superior processability coupled with improved mechanical properties that exhibit reduced anisotropy and reduced corrosion rates compared to conventional cast/wrought processed material. PM processing results in a microstructure containing a uniform distribution of second phase borides and gadolinides, and the morphology of the gadolinides prevents the formation low melting point Gd-bearing phases at solidifying austenite boundaries. The new T316-based materials containing both B and Gd exhibit superior corrosion resistance compared to straight B-bearing T304 materials. By keeping the B content < 1 weight percent (%) and using Gd to attain an equivalent B (B{sub Eq}) content higher than that achievable through the use of B only, the new materials exhibit superior ductility, toughness and bendability as a result of significantly reduced area fraction of Cr-rich M{sub 2}B borides. Limiting the total area fraction of second phase particles to < 22% insures a product with superior bendability. By restricting B to < 1% and using Gd up to 2.5%, B{sub Eq} levels approaching 12% can be attained that provide a cost effective improvement in thermal neutron absorption capability compared to using B-10 enriched boron. The new materials can be easily bent during fabrication compared to existing metal matrix composite materials while offering similar thermal neutron absorption capability. Production lots containing B{sub Eq} levels of 4.0 and 7.5% (Micro-Melt{sup R} DuoSorb{sup TM} 316NU-40 and 75, respectively) are in the process of being fabricated for customer trial material. (authors)

36 MATERIALS SCIENCE↗
DOE OSTI2024

Risk Considerations of Transitioning CO2-EOR Field to CO2 storage Field: Case Study

In the United States (U.S.), carbon dioxide (CO2) injection wells at EOR sites are currently regulated as Class II wells under the U.S. Environmental Protection Agency’s (EPA) Underground Injection Control (UIC) program while dedicated geological CO2 storage (GCS) wells are considered Class VI wells. A CO2-EOR facility considering a transitioning from tertiary oil recovery to injecting CO2 for the primary purpose of long-term storage is required to obtain a Class VI permit where this transition poses an increased risk to underground sources of drinking water. This study considers how transitioning operations from CO2-EOR to storage can impact reservoir plume and pressure transient in the storage envelope, and how these changes could impact area of review and potential unwanted fluid migration. We developed a case study to assess subsurface response and leakage risks associated with a representative, hypothetical operation in a carbonate reservoir. This reservoir transitions from tertiary hydrocarbon recovery to dedicated GCS. Reservoir simulations were run for a set of credible CO2-EOR scenarios to estimate distributions of fluids phases and pressures throughout the model domain after CO2 flooding as well as forecasting the behavior of the reservoir after the transition to a dedicated storage phase. The evolutions from all simulated scenarios were used as the basis for leakage risk quantification using the National Risk Assessment Partnership’s Open-Source Integrated Assessment Model (NRAP-Open-IAM) with a novel reduced-order model to estimate time-dependent leakage of CO2, brine, and hydrocarbon fluids through potentially leaky wells. Results include a description of reservoir response, an estimate of the areal extent that could potentially be impacted by leakage to underground sources of drinking water, and estimates of the magnitude of potential leakage. Considerations for dedicated storage injection well selection, injectivity, and injection scheme performance and potential leakage risk are presented, with implications for risk assessment of well transition discussed. This study presents a risk-based workflow for the Class II to Class VI well transition. Integrating credible numerical simulation of viable CO2-EOR to dedicated CO2 storage with quantitative risk assessment tools, such as the NRAP-Open-IAM, will provide a valuable means to devise operational scenarios and inform decision-making related to storage benefit, leakage risk, and liability. Presented at the SPE/AAPG/SEG Carbon Capture Utilization and Storage Conference in Houston, TX, March 11-13, 2024.

Liu, Guoxiang↗
DOE OSTI2024

Development of a Computational Framework for Multiphysics Multiphase Species Tracking using NEAMS Tools

This report implements a high-fidelity multiphysics modeling framework using the Nuclear Energy Advanced Modeling and Simulation (NEAMS) program tools to track isotopic species in Molten Salt Reactors (MSRs), with a specific focus on the 91-depletion chain within the Molten Salt Reactor Experiment (MSRE). The model integrates neutronics, thermal-hydraulics, depletion, and thermochemistry to simulate the production, transport, and phase transitions of isotopes under steady-state and transient conditions. The main findings reveal that isotopes such as bromine-91 largely remain in the liquid phase, while others, including krypton-91and yttrium-91, transition to the gas phase, significantly influencing the reactor’s radiological source term. The study also shows that during transients, like a reactivity insertion transient, rapid void formation and the expansion of the liquid-gas interface led to substantial transfers of dissolved isotopes into the gas phase, altering isotope distribution and largely increasing the source term in the off-gas system. Additionally, the research highlights that short-lived isotopes dominate the initial off-gas response during transients, while longer-lived isotopes determine the equilibrium state, underscoring the necessity of dynamic simulations for accurate species tracking and reactor safety analysis. The developed methodology will be applied in the future to the tracking of a larger number of species and introduce other species tracking mechanisms, such as deposition and plating.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2016

GAMMA-RAY EMISSION FROM PSR J0007+7303 USING SEVEN YEARS OF FERMI LARGE AREA TELESCOPE OBSERVATIONS

Based on more than seven years of Fermi Large Area Telescope Pass 8 data, we report on a detailed analysis of the bright gamma-ray pulsar (PSR) J0007+7303. We confirm that PSR J0007+7303 is significantly detected as a point source also during the off-peak phases with a test statistic value of 262 (∼16 σ ). In the description of the off-peak spectrum of PSR J0007+7303, a power law with an exponential cutoff at 2.7 ± 1.2 ± 1.3 GeV (the first/second uncertainties correspond to statistical/systematic errors) is preferred over a single power law at a level of 3.5 σ . The possible existence of a cutoff hints at a magnetospheric origin of the emission. In addition, no extended gamma-ray emission is detected that is compatible with either the supernova remnant (CTA 1) or the very high-energy (>100 GeV) pulsar wind nebula. A flux upper limit of 6.5 × 10{sup −12} erg cm{sup −2} s{sup −1} in the energy range 10–300 GeV is reported, for an extended source assuming the morphology of the VERITAS detection. During on-peak phases, a sub-exponential cutoff is significantly preferred (∼11 σ ) for representing the spectral energy distribution, in both the phase-averaged and phase-resolved spectra. Three glitches are detected during the observation period and we found no flux variability at the time of the glitches or in the long-term behavior. We also report the discovery of a previously unknown gamma-ray source in the vicinity of PSR J0007+7303, Fermi J0020+7328, which we associate with the z = 1.781 quasar S5 0016+73. A concurrent analysis of this source is needed to correctly characterize the behavior of CTA 1 and it is also presented in the paper.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1988

What ferric oxide/oxyhydroxide phases are present on Mars

The weathering history of Mars can be deduced largely from the mineralogy and distribution of ferric oxide/oxyhydroxide phases. As discussed, some insights can be gained through spectrophotometric remote sensing, but absolute determinations must depend on direct laboratory analysis of returned Martian samples.

Morris, Richard V.↗
DOE OSTI2018

Role of refractory inclusions in the radiation-induced microstructure of APMT

Kanthal APMT is a promising FeCrAl-based alloy for accident-tolerant fuel cladding because of its excellent high-temperature oxidation resistance. In this study, powder metallurgy Kanthal APMT alloy, neutron irradiated to 1.8 dpa at nominally 382 °C, was characterized. On-zone STEM imaging revealed that radiation-induced dislocation loops with Burgers vectors of a/2 <111 > or and black dots tended to agglomerate in the vicinity of refractory inclusions. The densities and sizes of these loops decreased with distance from the inclusion-matrix interfaces. In addition, high-resolution energy-dispersive X-ray spectroscopy mapping was used to determine the inclusions to be either yttrium- or silicon-rich, as well as to detect the radial distribution of radiation-enhanced α' phase near these inclusions. A high density of randomly distributed Cr-rich α' phase was found, regardless of the presence of inclusions. Here, the results from this study provide insights into how microstructural features can locally tailor the radiation-induced defects in FeCrAl-based alloys.

36 MATERIALS SCIENCE↗
DOE OSTI2015

A SEARCH FOR PULSATIONS FROM GEMINGA ABOVE 100 GeV WITH VERITAS

We present the results of 71.6 hr of observations of the Geminga pulsar (PSR J0633+1746) with the VERITAS very-high-energy gamma-ray telescope array. Data taken with VERITAS between 2007 November and 2013 February were phase-folded using a Geminga pulsar timing solution derived from data recorded by the XMM- Newton and Fermi-LAT space telescopes. No significant pulsed emission above 100 GeV is observed, and we report upper limits at the 95% confidence level on the integral flux above 135 GeV (spectral analysis threshold) of 4.0 × 10{sup –13} s{sup –1} cm{sup –2} and 1.7 × 10{sup –13} s{sup –1} cm{sup –2} for the two principal peaks in the emission profile. These upper limits, placed in context with phase-resolved spectral energy distributions determined from 5 yr of data from the Fermi-Large Area Telescope (LAT), constrain possible hardening of the Geminga pulsar emission spectra above ∼50 GeV.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS2018

Auralization of an Unmanned Aerial Vehicle Under Propeller Phase Control

Community noise has been identified as a major barrier to entry into service of unmanned aerial vehicle platforms. Common among such vehicle architectures is a distributed electric propulsion system, in which many propellers and/or rotors are used for thrust and/or lift. A promising noise reduction technique was recently developed to favorably modify the vehicle source noise directivity, by adjusting the relative azimuthal position of the prop/rotor blades between propulsors. Un- der idealized conditions, such phase control can yield noise reductions on the order of 20 dB at a ground observer relative to the average case having a random phase distribution. However, human perception of the resulting noise may not be fully captured by such a simple acoustic measure. To this end, this paper under- takes the auralization of the tonal vehicle noise. Specifically, total propeller tonal noise is optimized over a set of observer zones, e.g., 45 deg. wedges, around the vehicle. Each zone represents a unique set of relative phases. The forward flight of the vehicle adjacent to a noise-sensitive area is simulated by prescribing a series of zones over the flight path having minimum noise in the direction of the ob- server. Auralizations and their associated metrics are compared with a reference condition.

Pascioni, Kyle A.↗
DOE OSTI2021

High-Entropy 2D Carbide MXenes: TiVNbMoC 3 and TiVCrMoC 3

Two-dimensional (2D) transition metal carbides and nitrides, known as MXenes, are a fast-growing family of 2D materials. MXenes 2D flakes have n + 1 (n = 1-4) atomic layers of transition metals interleaved by carbon/nitrogen layers, but to-date remain limited in composition to one or two transition metals. In this study, by implementing four transition metals, we report the synthesis of multi-principal-element high-entropy M 4 C 3 T x MXenes. Specifically, we introduce two high-entropy MXenes, TiVNbMoC 3 T x and TiVCrMoC 3 T x , as well as their precursor TiVNbMoAlC 3 and TiVCrMoAlC 3 high-entropy MAX phases. We used a combination of real and reciprocal space characterization (X-ray diffraction, X-ray photoelectron spectroscopy, energy dispersive X-ray spectroscopy, and scanning transmission electron microscopy) to establish the structure, phase purity, and equimolar distribution of the four transition metals in high-entropy MAX and MXene phases. We use first-principles calculations to compute the formation energies and explore synthesizability of these high-entropy MAX phases. We also show that when three transition metals are used instead of four, under similar synthesis conditions to those of the four-transition-metal MAX phase, two different MAX phases can be formed (i.e., no pure single-phase forms). This finding indicates the importance of configurational entropy in stabilizing the desired single-phase high-entropy MAX over multiphases of MAX, which is essential for the synthesis of phase-pure high-entropy MXenes. The synthesis of high-entropy MXenes significantly expands the compositional variety of the MXene family to further tune their properties, including electronic, magnetic, electrochemical, catalytic, high temperature stability, and mechanical behavior.

2D materials↗