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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 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
NASA NTRS2021

Summertime Transport Pathways from Different Northern Hemisphere Regions into the Arctic

Trace gases and aerosols play an important role in Arctic chemistry and climate. As most Arctic tracers and aerosols are transported from midlatitude source regions, long-range transport into the Arctic is one of the key factors to understand the current and future states of Arctic climate. While previous studies have investigated the airmass fraction and transit time distribution in the Arctic, the actual transport pathways and their underlying dynamics and efficiencies are yet to be understood. In this study, we implement a large ensemble of idealized tagged pulse passive tracers in the Whole Atmosphere Community Climate Model version 5 to identify and analyze summertime transport pathways from different Northern Hemisphere surface regions into the Arctic. Three different transport pathways are identified as those associated with fast, intermediate and slow time scales. Midlatitude tracers can be transported into the Arctic in the troposphere via the fast transport pathway (~8 days), which moves tracers northward from the source region mainly through transient eddies. For the intermediate transport pathway, which happens on 1~3 weeks’ time scales, midlatitude tracers are first zonally transported by the jet stream, and then advected northward into the Arctic over Alaska and northern North Atlantic. Tropical and subtropical tracers are transported into the Arctic lower stratosphere via the slow transport pathway (1~3 months), as the tracers are lifted upward into the tropical and subtropical lower stratosphere, and then transported into the Arctic following the isentropic surfaces.

Trace gases↗
DOE OSTI2024

Emergent Ferromagnetism in CaRuO 3 /CaMnO 3 (111)-Oriented Superlattices

The boundary between CaRuO 3 and CaMnO 3 is an ideal test bed for emergent magnetic ground states stabilized through interfacial electron interactions. In this system, nominally antiferromagnetic and paramagnetic materials combine to yield interfacial ferromagnetism in CaMnO 3 due to electron leakage across the interface. In this work, we show that the crystal symmetry at the surface is a critical factor determining the nature of the interfacial interactions. Specifically, by growing CaRuO 3 /CaMnO 3 heterostructures along the (111) instead of the (001) crystallographic axis, we achieve a 3-fold enhancement of the magnetization and involve the CaRuO 3 layers in the ferromagnetism, which now spans both constituent materials. Importantly, the stabilization of a net magnetic moment in CaRuO 3 through strain effects has been long-sought but never consistently achieved, and our observations demonstrate the importance of interface engineering in the development of new functional heterostructures.

36 MATERIALS SCIENCE↗
DOE OSTI2022

An Energetic Diagnostic of Tropical Cyclone Size in f –Plane Simulations

As a major feature of tropical cyclones (TCs), controlling factors of TC outer size or size scaling remains a fundamental scientific question. The Rossby deformation radius and a natural extent associated with potential intensity have been proposed as two scalings of TC size. But neither of them satisfactorily captures the sensitivity of TC size to sea surface temperature (SST) in idealized f-plane simulations. Inspired by the studies of the Hadley circulation, here we proposed a new TC scaling based on an energetic diagnostic scaling. TC size is primarily a ratio of the secondary circulation strength to subsidence velocity, further determined by the total atmospheric heating in the ascending area, the gross moist stability, the diabatic cooling, and the dry static stability. The former two is based on the moist energetic budget applied to the whole storm structure, while the latter two is based on the dry thermodynamic budget applied to the subsidence areas. The new scaling well captured the sensitivity of TC size to SST in idealized f-plane simulations, partly resulted from expanded ascending area, increased surface moisture deficit, and weakened subsidence with increased SST.

58 GEOSCIENCES↗
DOE OSTI2026

Variability of MHD instabilities in benign termination of high-current runaway electron beams in the JET and DIII-D tokamaks

Benign termination, in which magnetohydrodynamic (MHD) instabilities deconfine runaway electrons (REs) following hydrogenic injections, is a promising strategy for mitigating dangerous RE loads after disruptions. Recent experiments on the Joint European Torus (JET) have explored this scenario at higher pre-disruptive plasma currents than are achievable on other devices, revealing challenges in obtaining benign terminations at I p ≥2.5 MA. This work analyzes the evolution of these high-current RE beams and their terminating MHD events using fast magnetic sensor measurements and EFIT equilibrium reconstructions for approximately 40 JET and 20 DIII-D tokamak discharges. On JET, unsuccessful non-benign terminations occur at low edge safety factor (q edge ≈ 2), and are preceded by intermittent, non-terminating MHD events at higher rational qedge. Trends in the internal inductance I i indicate more peaked RE current profiles in the high-I p non-benign population, which may hinder successful recombination through re-ionization of the companion plasma. In contrast, benign terminations on JET typically occur at higher q edge ≥3 and exhibit less peaked RE current profiles. DIII-D displays a broader range of terminating edge safety factors, again correlated with the measured values. Across both tokamaks, the RE current peaking is therefore found to determine which MHD instability boundary is encountered, a result confirmed by linear resistive MHD modeling with the CASTOR3D code. Measured growth rates are similar for benign and non-benign cases, indicating that ideal MHD timescales at low density after hydrogenic injection do not alone explain efficient RE deconfinement. Instead, non-benign cases are most readily characterized by their comparably lower overall MHD perturbation amplitudes δB. These observations suggest that the interplay between ideal and resistive dynamics governs the termination process, with implications for extrapolating benign RE termination to high-I p reactor scenarios.

MHD instabilities↗
DOE OSTI2022

Numerical investigation of laser-driven shock interaction with a deformable particle

A laser-driven shock propagating through an isolated particle embedded in a plastic (CH) target was studied using the radiation-hydrodynamic code FLASH. Preliminary simulations using IONMIX equations of state (EOS) showed significant differences in the shock Hugoniot of aluminum compared to experimental data in the low-pressure regime [O(10) GPa], resulting in higher streamwise compression and deformation of an aluminum particle. Hence, a simple modification to the ideal gas EOS was developed and employed to describe the target materials and examine the particle dynamics. The evolution of the pressure field demonstrated a complex wave interaction, resulting in a highly unsteady particle drag which featured two drag minima due to shock focusing at the rear end of the particle and rarefaction stretching due to laser shut-off. Although ~30% lateral expansion and ~25% streamwise compression were observed, the aluminum particle maintained considerable integrity without significant distortion. Additional simulations examined the particle response for a range of particle densities, sizes, and acoustic impedances. The data revealed that lighter particles such as aluminum gained significant momentum, reaching up to ~96% of the shocked CH's speed, compared to ~29% for the heavier tungsten particles. Despite the differences seen in the early stage of shock interaction, particles with varying acoustic impedances ultimately reached the same peak velocity. This identified particle-to-host density ratio is an important factor in determining the inviscid terminal velocity of the particle. In addition, the modified EOS model presented in this study could be used to approximate solid materials in hydrocodes that lack material strength models.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2024

High-throughput approach for investigating interdiffusion in medium- and high-entropy alloys

Interdiffusion experiments are usually time-consuming and tedious since diffusion couples must be annealed at several temperatures for a long time. The efforts required to study interdiffusion in multicomponent alloys increase dramatically as multiple diffusion couples are required to cover broad composition ranges and determine the diffusivities of individual elements in different chemical environments. To circumvent this challenge, we present a high-throughput approach applicable to single-phase and compositionally complex alloys, which are assumed to approximate ideal solid solutions. Here, a simple diffusion-multiple experiment combined with a physically based kinetic model is proposed to efficiently determine the diffusion coefficients of the constituent elements in quaternary CrFeCoNi alloys. Compared with tracer diffusivities reported in the literature, the results, thus, obtained do not differ by more than a factor of 2 and were obtained from a single interdiffusion experiment. In contrast, the diffusivities simulated with commercial mobility and thermodynamic databases are strongly overestimated by a factor ranging from 1 to 16. Therefore, our approach enables high-throughput determination of diffusivities and can help in the design of alloys for high-temperature applications where diffusion plays a key role.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Pipeline Hydrogen Decarbonization and Repurposing Analyzers (P-HyDRAs)

The Pipeline Hydrogen Decarbonization and Repurposing Analyzers (P-HyDRAs) are a set of prototype computational tools for simulating and optimizing midstream natural gas pipeline system operations subject to location and time-dependent hydrogen blending. The models can accurately resolve dynamic gas flows through large-scale pipeline networks using non-ideal gas equations of state. The codes can be used as decision support for planning and design decisions involving intra-day energy flow schedules as well as spatiotemporal economic values of natural gas, hydrogen, and net energy delivered to consumers while ensuring that pipeline hydraulic limitations, gas compressor station constraints, operational factors, and pre-existing shipping contracts are satisfied. The inputs to the codes are a model of the pipeline system as well as time-series data that specify boundary conditions on the network. For optimization, the code module requires price and quantity offers for natural gas and hydrogen and price and quantity bids for energy, which are used as time-dependent constraints in an optimal control problem. The outputs are time-series data that provide a predictive simulation of gas flows, mass fractions, and pressures, or with additional degrees of freedom give an approximately optimal solution for gas injections/withdrawals, compressor settings, and sensitivities to the objective function that provide locational values of energy.

Zlotnik, Anatoly↗
NASA NTRS2007

Radiative Heating Methodology for the Huygens Probe

The radiative heating environment for the Huygens probe near peak heating conditions for Titan entry is investigated in this paper. The task of calculating the radiation-coupled flowfield, accounting for non-Boltzmann and non-optically thin radiation, is simplified to a rapid yet accurate calculation. This is achieved by using the viscous-shock layer (VSL) technique for the stagnation-line flowfield calculation and a modified smeared rotational band (SRB) model for the radiation calculation. These two methods provide a computationally efficient alternative to a Navier-Stokes flowfield and line-by-line radiation calculation. The results of the VSL technique are shown to provide an excellent comparison with the Navier-Stokes results of previous studies. It is shown that a conventional SRB approach is inadequate for the partially optically-thick conditions present in the Huygens shock-layer around the peak heating trajectory points. A simple modification is proposed to the SRB model that improves its accuracy in these partially optically-thick conditions. This modified approach, labeled herein as SRBC, is compared throughout this study with a detailed line-by-line (LBL) calculation and is shown to compare within 5% in all cases. The SRBC method requires many orders-of-magnitude less computational time than the LBL method, which makes it ideal for coupling to the flowfield. The application of a collisional-radiative (CR) model for determining the population of the CN electronic states, which govern the radiation for Huygens entry, is discussed and applied. The non-local absorption term in the CR model is formulated in terms of an escape factor, which is then curve-fit with temperature. Although the curve-fit is an approximation, it is shown to compare well with the exact escape factor calculation, which requires a computationally intensive iteration procedure.

Johnston, Christopher O.↗
NASA NTRS1983

Rain estimation from satellites: An examination of the Griffith-Woodley technique

The Griffith-Woodley Technique (GWT) is an approach to estimating precipitation using infrared observations of clouds from geosynchronous satellites. It is examined in three ways: an analysis of the terms in the GWT equations; a case study of infrared imagery portraying convective development over Florida; and the comparison of a simplified equation set and resultant rain map to results using the GWT. The objective is to determine the dominant factors in the calculation of GWT rain estimates. Analysis of a single day's convection over Florida produced a number of significant insights into various terms in the GWT rainfall equations. Due to the definition of clouds by a threshold isotherm the majority of clouds on this day did not go through an idealized life cycle before losing their identity through merger, splitting, etc. As a result, 85% of the clouds had a defined life of 0.5 or 1 h. For these clouds the terms in the GWT which are dependent on cloud life history become essentially constant. The empirically derived ratio of radar echo area to cloud area is given a singular value (0.02) for 43% of the sample, while the rainrate term is 20.7 mmh-1 for 61% of the sample. For 55% of the sampled clouds the temperature weighting term is identically 1.0. Cloud area itself is highly correlated (r=0.88) with GWT computed rain volume. An important, discriminating parameter in the GWT is the temperature defining the coldest 10% cloud area. The analysis further shows that the two dominant parameters in rainfall estimation are the existence of cold cloud and the duration of cloud over a point.

Negri, A. J.↗
NASA NTRS1984

Rain estimation from satellites - An examination of the Griffith-Woodley Technique

The Griffith-Woodley Technique (GWT) is an approach to estimating precipitation using infrared observations of clouds from geosynchronous satellites. It is examined in three ways: an analysis of the terms in the GWT equations; a case study of infrared imagery portraying convective development over Florida; and the comparison of a simplified equation set and resultant rain map to results using the GWT. The objective is to determine the dominant factors in the calculation of GWT rain estimates. Analysis of a single day's convection over Florida produced a number of significant insights into various terms in the GWT rainfall equations. Due to the definition of clouds by a threshold isotherm the majority of clouds on this day did not go through an idealized life cycle before losing their identity through merger, splitting, etc. As a result, 85 percent of the clouds had a defined life of 0.5 or 1 h. For these clouds, the terms in the GWT which are dependent on cloud life history become essentially constant. The empirically derived ratio of radar echo area to cloud area is given a singular value (0.02) for 43 percent of the sample, while the rainrate term is 20.7 mmh-1 for 61 percent of the sample. For 55 percent of the sampled clouds, the temperature weighting term is identically 1.0. Cloud area itself is highly correlated (r = 0.88) with GWT computed rain volume. An important, discriminating parameter in the GWT is the temperature defining the coldest 10 percent cloud area. The analysis further shows that the two dominant parameters in rainfall estimation are the existence of cold cloud and the duration of cloud over a point. Previously announced in STAR as N84-13735

Negri, A. J.↗
NASA NTRS2015

Options for Staging Orbits in Cis-Lunar Space

NASA has been studying options to conduct missions beyond Low Earth Orbit, but within the Earth-Moon system, in preparation for deep space exploration including human missions to Mars. Referred to as the Proving Ground, this arena of exploration activities will enable the development of human spaceflight systems and operations to satisfy future exploration objectives beyond the cis-lunar environment. One option being considered includes the deployment of a habitable element or elements, which could be used as a central location for aggregation of supplies and resources for human missions in cis-lunar space and beyond. Characterizing candidate orbit locations for this asset and the impacts on system design and mission operations is important in the overall assessment of the options being considered. The orbits described in this paper were initially selected by taking advantage of previous studies conducted by NASA and the work of other authors. In this paper orbits are assessed for their relative attractiveness based on various factors. First, a set of constraints related to the capability of the combined Orion and SLS system to deliver humans and cargo to and from the orbit are evaluated. Second, the ability to support potential lunar surface activities is considered. Finally, deployed assets intended to spend multiple years in the Proving Ground would ideally require minimal station keeping costs to reduce the mass budget allocated to this function. Additional mission design drivers include potential for uninterrupted communication with deployed assets, thermal, communications, and other operational implications. The results of the characterization and evaluation of the selected orbits indicate a Near Rectilinear Orbit (NRO) is an attractive candidate as an aggregation point or staging location for operations. In this paper, the NRO is further described in terms which balance a number of key attributes that favor a variety of mission classes to meet multiple, sometimes competing, constraints.

Whitley, Ryan↗
NASA NTRS1973

Two-dimensional analytical and experimental performance comparison for a compressor stator section with D-factor of 0.47

Analytically computed flow parameters were compared to measured values for the midspan double-circular-arc section of a stator in subsonic flow. Analytical procedures included calculations for inviscid flow, blade surface boundary layers, and loss coefficients. Comparisons were made at three incidence angles. Methods for prescribing the exit fluid angle in inviscid flow calculations were investigated. Measured loss coefficients were compared to calculated values. Two methods for predicting performance involving iterative use of ideal flow and boundary layer calculations were investigated.

Sanger, N. L.↗
DOE OSTI2023

Utah FORGE 4-2492: Design and Implementation of Innovative Stimulation Treatments to Maximize Energy Recovery - Workshop Presentation

This is a presentation on the Design and Implementation of Innovative Stimulation Treatments to Maximize Energy Recovery Efficiency at the Utah FORGE Site project by The University of Texas at Austin, presented by Professor Mukul M. Sharma. The project's objectives were to place fractures uniformly in a horizontal well (improve cluster efficiency) to ensure uniform distribution of flow into all hydraulic fractures, maximize the area of the created fracture network, ensure connectivity of the fractures from the injector to the producer, and optimize fracture size. This presentation was featured in the Utah FORGE R&D Annual Workshop on September 7, 2023. The workshop provided a valuable opportunity to explore the progress made in each of the 17 Research and Development projects funded under Solicitation 2020-1 which aim to enhance our understanding of the crucial factors influencing the development of Enhanced Geothermal Systems (EGS) reservoirs and resources.

15 GEOTHERMAL ENERGY↗
NASA NTRS1976

Rocket-borne time-of-flight mass spectrometry

Theoretical and numerical analyses are made of planar, cylindrical and spherical-electrode two-field time-of-flight mass spectrometers in order to optimize their operating conditions. A method is introduced which can improve the resolving power of these instruments by a factor of 7.5. Potential barrier gating in time-of-flight mass spectrometers is also analyzed. Experimental studies of a miniature cylindrical-electrode and a hemispherical-electrode time-of-flight mass spectrometer are presented. Their sensitivity and ability to operate at D-region pressures with an open source make them ideal instruments for D-region ion composition measurements. A sounding rocket experiment package carrying a cylindrical electrode time-of-flight mass spectrometer was launched. The data indicate that essentially 100% of the positive electric charge on positive ions is carried by ions with mass-to-charge ratios greater than 500 below an altitude of 92 km. These heavy charge carriers were present at altitudes up to about 100 km.

Reiter, R. F.↗
NASA NTRS2007

Evaluating the Use of Tribocharging in the Electrostatic Beneficiation of Lunar Simulant

Any future lunar base needs materials to provide thermal and radiation protection. Many factors point to the use of lunar materials as industrial feedstocks. Sintering of full-scale bricks using whole lunar dust has been accomplished. Refinement of soil beneficial before processing means less energy. Triboelectric separation of coal from minerals, quartz from feldspar, and phosphorous from silica and iron ore successively achieved. The Lunar environment ideal for electrostatic separation (1) lack of moisture (2) lower gravitational pull (3) higher voltages in vacuum

Trigwell, S.↗
NASA NTRS2016

Key Elements of a Low Voltage, Ultracompact Plasma Spectrometer

Taking advantage of technological developments in wafer-scale processing over the past two decades, such as deep etching, 3-D chip stacking, and double-sided lithography, we have designed and fabricated the key elements of an ultracompact 1.5cm (exp 3)plasma spectrometer that requires only low-voltage power supplies, has no microchannel plates, and has a high aperture area to instrument volume ratio. The initial design of the instrument targets the measurement of charged particles in the 3-20keV range with a highly directional field of view and a 100 duty cycle; i.e., the entire energy range Is continuously measured. In addition to reducing mass, size, and voltage requirements, the new design will affect the manufacturing process of plasma spectrometers, enabling large quantities of identical instruments to be manufactured at low individual unit cost. Such a plasma spectrometer is ideal for heliophysics plasma investigations, particularly for small satellite and multispacecraft missions. Two key elements of the instrument have been fabricated: the collimator and the energy analyzer. An initial collimator transparency of 20 with 3deg x 3deg angular resolution was achieved. The targeted 40 collimator transparency appears readily achievable. The targeted energy analyzer scaling factor of 1875 was achieved; i.e.20 keV electrons were selected for only a 10.7V bias voltage in the energy analyzer.

Scime, E. E.↗
DOE OSTI2023

Linking impact melt redox with crustal weathering regime

Abstract Impact melting and outgassing of impact melts were important processes shaping the crust and atmosphere of early Earth and Mars. The redox state of impact melts influences the gases they release, but the controls on impact melt redox are not well understood. Here, we present Fe micro–X-ray absorption near edge structure (μ-XANES) measurements of a suite of impact melt glasses from Lonar crater, India. As an impact into continental flood basalts, Lonar crater is an ideal analog for impacts into basaltic crust on early Earth and Mars. The Fe-μ-XANES technique permits robust characterization of the Fe3+/ΣFe ratio and therefore redox conditions in Lonar glasses. We found a range in Fe3+/ΣFe of 0.21–0.49 among Lonar glasses, including substantial intraclast variations. We conclude that a primary factor driving these variations was pre-impact oxidative weathering of target rocks. The coupling between crustal weathering regime and speciation of gases released from impact melts implies that impact melt outgassing could act as a feedback mechanism to reinforce prevailing surface redox conditions.

Geology↗
DOE OSTI2022

A Novel EGFRvIII T-Cell Bispecific Antibody for the Treatment of Glioblastoma

Abstract T-cell bispecific antibodies (TCB) are engineered molecules that bind both the T-cell receptor and tumor-specific antigens. Epidermal growth factor receptor variant III (EGFRvIII) mutation is a common event in glioblastoma (GBM) and is characterized by the deletion of exons 2–7, resulting in a constitutively active receptor that promotes cell proliferation, angiogenesis, and invasion. EGFRvIII is expressed on the surface of tumor cells and is not expressed in normal tissues, making EGFRvIII an ideal neoantigen target for TCBs. We designed and developed a novel 2+1 EGFRvIII-TCB with optimal pharmacologic characteristics and potent antitumor activity. EGFRvIII-TCB showed specificity for EGFRvIII and promoted tumor cell killing as well as T-cell activation and cytokine secretion only in patient-derived models expressing EGFRvIII. Moreover, EGFRvIII-TCB promoted T-cell recruitment into intracranial tumors. EGFRvIII-TCB induced tumor regression in GBM animal models, including humanized orthotopic GBM patient-derived xenograft models. Our results warrant the clinical testing of EGFRvIII-TCB for the treatment of EGFRvIII-expressing GBMs.

Oncology↗