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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 271 records · Page 15
All sourcesNASA NTRSDOE OSTI
DOE OSTI2026

Laboratory Investigations of Aerosol-Cloud Interactions in an Entraining, Turbulent Environment (Final Technical Report)

The effects that aerosol particles have on clouds in Earth’s atmosphere and the role that clouds play in determining the fate of aerosol particles play a crucial role in determining the human experience on this planet. These interwoven interactions can determine whether it rains or snows, is comfortable, hot or cold, or whether the cloud you gaze at in the sky looks like a tiger or a lump of porridge. How clouds mix with the air surrounding them, a process known as entrainment, further affects these processes. We conducted laboratory experiments of aerosol-cloud interactions in a setting in which we can measure the effects of entrainment – the first laboratory experiments since the pioneering work of Latham and Reed in 1977. We measured the effects of entrainment on aerosol-cloud interactions in the Pi Chamber and also used a state-of-the-art large eddy simulation (LES) to investigate processes in fine detail.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2024

Constraining the Dense Matter Equation of State with New NICER Mass–Radius Measurements and New Chiral Effective Field Theory Inputs

Pulse profile modeling of X-ray data from the Neutron Star Interior Composition Explorer is now enabling precision inference of neutron star mass and radius. Combined with nuclear physics constraints from chiral effective field theory (χEFT), and masses and tidal deformabilities inferred from gravitational-wave detections of binary neutron star mergers, this has led to a steady improvement in our understanding of the dense matter equation of state (EOS). Here, we consider the impact of several new results: the radius measurement for the 1.42 M ⊙ pulsar PSR J0437−4715 presented by Choudhury et al., updates to the masses and radii of PSR J0740+6620 and PSR J0030+0451, and new χEFT results for neutron star matter up to 1.5 times nuclear saturation density. Using two different high-density EOS extensions—a piecewise-polytropic (PP) model and a model based on the speed of sound in a neutron star (CS)—we find the radius of a 1.4 M ⊙ (2.0 M ⊙ ) neutron star to be constrained to the 95% credible ranges ${12.28}_{-0.76}^{+0.50}$ km (${12.33}_{-1.34}^{+0.70}$ km) for the PP model and ${12.01}_{-0.75}^{+0.56}$ km (${11.55}_{-1.09}^{+0.94}$ km) for the CS model. The maximum neutron star mass is predicted to be ${2.15}_{-0.16}^{+0.14}$M ⊙ and ${2.08}_{-0.16}^{+0.28}$M ⊙ for the PP and CS models, respectively. We explore the sensitivity of our results to different orders and different densities up to which χEFT is used, and show how the astrophysical observations provide constraints for the pressure at intermediate densities. Moreover, we investigate the difference R 2.0 − R 1.4 of the radius of 2 M ⊙ and 1.4 M ⊙ neutron stars within our EOS inference.

gravitational wave sources↗
DOE OSTI2022

Measurement of cold nuclear matter effects for inclusive J / ψ in p +Au collisions at s NN = 200 GeV

Measurement by the STAR experiment at RHIC of the cold nuclear matter (CNM) effects experienced by inclusive J / ψ at mid-rapidity in 0-100% p +Au collisions at s NN = 200 GeV is presented. Such effects are quantified utilizing the nuclear modification factor, R p Au , obtained by taking a ratio of J / ψ yield in p +Au collisions to that in p + p collisions scaled by the number of binary nucleon-nucleon collisions. The differential J / ψ yield in both p + p and p +Au collisions is measured through the dimuon decay channel, taking advantage of the trigger capability provided by the Muon Telescope Detector in the RHIC 2015 run. Consequently, the J / ψ R p Au is derived within the transverse momentum ( p T ) range of 0 to 10 GeV/ c . A suppression of approximately 30% is observed for p T < 2 GeV/ c , while J / ψ R p Au becomes compatible with unity for p T greater than 3 GeV/ c , indicating the J / ψ yield is minimally affected by the CNM effects at high p T . Comparison to a similar measurement from 0-20% central Au+Au collisions reveals that the observed strong J / ψ suppression above 3 GeV/ c is mostly due to the hot medium effects, providing strong evidence for the formation of the quark-gluon plasma in these collisions. Several model calculations show qualitative agreement with the measured J / ψ R p Au , while their agreement with the J / ψ yields in p + p and p +Au collisions is worse.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2021

County Economic Impact Index: Measuring the ongoing economic effects of COVID-19

The County Economic Impact Index (CEII) estimates the change in overall county-level economic activity during the COVID-19 pandemic relative to January 2020. It shows which counties may be more susceptible to large reductions in economic activity compared to normal conditions by looking at which industries make up each county’s economy and then tracking monthly changes in industry employment at the national level. Economic activity in the CEII is measured by the total value added of all industries within the county. Counties with economic activities dominated by industries experiencing rising unemployment can expect larger direct impacts to their local economies, particularly if the industries account for a large portion of the economic output of that county. Results are available for all U.S. counties, as well as the District of Columbia, Puerto Rico municipios, and the U.S. Virgin Islands.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2024

Measurement of the thermal effects in the dispersion relation of the dust acoustic wave in the presence of a magnetic field

This award supported an experimental study of the properties of the dust acoustic wave, low-frequency, l ongitudinal wave mode that propagates through the dust component of a dusty plasma system and is self-excited by the free energy from the ion streaming p ast the dust, in the presence of a high magnetic fiel d. In particular, this project measured the thermal state of dusty plasma system by measuring the dispersi on relation of the dust acoustic wave while varying (1) the strength and direction of the magnetic field relative to the propagation direction of the wave and (2) the neutral gas pressure. By exploiting the unique ability of the MDPX facility to generate a dusty plasma in a high magnetic field environment, it is possible to create a preferential ion flow along the magnetic field lines as the ions become magnetized. In this way, the magnetic field strength can be used to control t he strength of the ion flow through the dust cloud an d provide insight into the contribution that one of the physical mechanisms, a two-stream ion-dust instability, thought to be responsible for high temperatures that have been previously observed might have. This work was completed over two, one-week long runs o n the Magnetized Dusty Plasma eXperiment (MDPX) in the Magnetized Plasma Research Laboratory at Auburn University and supported by work at Wittenberg University (development of an electrode system that would allow for the wave mode to propagate in th e direction of gravity as the orientation of the magnetic field is changed by rotating the magnets on the M DPX device, analysis of data acquired during the experimental campaigns, testing alternative strategies to form a dust cloud based on what was learned the first experimental campaign, etc.).

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Analysis of Two Models for the Angular Structure of the Outflows Producing the Swift/XRT “Larger-angle Emission” of Gamma-Ray Bursts

The quasi-instantaneous emission from a relativistic surface endowed with a Lorentz factor that decreases away from the outflow symmetry axis can naturally explain the three phases observed by Swift X-Ray Telescope (XRT) in gamma-ray bursts (GRBs) and their afterglows (GRB tail, afterglow plateau, and postplateau) based only on the angular change of the relativistic Doppler boost across the outflow surface. We develop further the analytical formalism of the “larger-angle emission” model for the case of “n-exponential” outflows (where the Lorentz factor Γ dependence of the angular location θ is Γ ~ exp{-(θ/θ c ) n }), and compare its ability to account for the X-ray emission of XRT afterglows relative to that of “power-law” outflows (Γ ∼ θ −g ). Power-law outflows yield longer afterglow plateaus, followed by slower postplateau flux decays than n-exponential outflows, features which may be used in identifying which type of angular structure is at work in a given afterglow. Identifying the Γ(θ) angular structure that accommodates XRT light curves is slightly complicated by the fact that the afterglow X-ray light curve is also determined by how two characteristics of the comoving-frame emission spectrum (peak energy $E'_p$ and peak intensity $i'_p$) change with the angular location or, equivalently, with the Lorentz factor. Here, we assume power-law Γ dependences of those spectral characteristics and find that, unlike power-law outflows, n-exponential outflows cannot account for plateaus with a temporal dynamical range larger than 100 (2 dex in logarithmic space). To capture all the information contained in XRT afterglow measurements (0.3–10 keV unabsorbed flux and effective spectral slope), we calculate 0.3 and 10 keV light curves using a broken-power-law emission spectrum of peak energy and low- and high-energy slopes that are derived from the effective slope measured by XRT. This economical peak energy determination is found to be consistent with the results of more expensive spectral fits. The angular distributions of the Lorentz factor, comoving frame peak energy, and peak intensity (Γ(θ), $E'_p$(θ), $i'_p$(θ)) constrain the (yet-to-be determined) convolution of various features of the production of relativistic jets by solar-mass black holes and of their propagation through the progenitor/circumburst medium, while the $E'_p$(Γ) and $i'_p$(Γ) dependences may constrain the GRB dissipation mechanism and the GRB emission process.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Sample environment effects on synchrotron-measured temperature profiles in an approximant of optical floating zone crystal growth

Even though the growth of crystals using optical floating zone furnaces has had an immense scientific impact, the implementation of this method remains more of an art than a science due to the difficulty of obtaining quantitative information about the sample thermal profile during crystal growth. Building on recent work demonstrating that in situ synchrotron studies can be used to map sample rod temperatures during heating, investigations were carried out to better understand how the sample environment affects the sample temperature profile. Through a combination of experimental studies and modeling efforts, it is shown that the environment in the furnace can strongly influence the sample temperature at the lamp focus, the steepness of the vertical temperature gradient, and the timescale required for sample heating and cooling - effects which can combine to produce a strong history-dependence to sample temperature profiles. It is demonstrated that the furnace effects can be effectively captured in thermal models, allowing both the steady-state and time-dependent behavior of the sample to be accurately reproduced with predictive models, and providing a launching point for improved furnace designs that can more readily deliver desired thermal profiles.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Effects of knock intensity measurement technique and fuel chemical composition on the research octane number (RON) of FACE gasolines: Part 1 – Lambda and knock characterization

The Research and Motor Octane Number (RON and MON) rate the knock propensity of gasoline in the Cooperative Fuel Research (CFR) engine by comparing the knock intensity of sample fuels relative to that of primary reference fuels (PRF), a binary blend of iso-octane and n-heptane. Important differences exist between standard octane testing and automotive spark ignition (SI) engine knock testing including speed, load, air-to-fuel equivalence ratio (lambda), and knock characterization, which lead to a discrepancy between a fuel’s RON rating and its knock resistance characterized on an automotive SI engine based on knock-limited spark advance. This publication is the first of a set of three publications which modify operating parameters of the RON test method (ASTM D2699) to investigate the effects of these differences with automotive SI engine knock-limited spark advance testing. A fuel’s standard RON is evaluated at the lambda of the highest knock intensity, whereas automotive SI engines typically operate at stoichiometry. Here, we analyze the effects of a stoichiometric RON rating methodology. Additionally, the knock intensity response from the standard CFR knockmeter system is compared to a cylinder pressure oscillation-based knock intensity at several lambda settings. All experiments were performed with a set of seven Coordinating Research Council (CRC) Fuels for Advanced Combustion Engines (FACE) gasolines with approximately 95 RON. The fuel chemical composition impacted the lambda of the highest knock intensity, which resulted in fuel-specific offsets between the standard and stoichiometric RON ratings. The knock system comparison showed significant offsets between cylinder pressure-based and knockmeter-based knock intensity levels.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Design progress for the 22 GeV CEBAF energy upgrade

In this work we examine the progress made in the design of the proposed FFA upgrade to the Continuous Electron Beam Accelerator Facility (CEBAF). This proposed upgrade will double the number of passes through the two linacs by replacing the two highest energy arcs with new Fixed Field Alternating Gradient (FFA) arcs, roughly doubling the energy. These FFA arcs will use permanent magnets in a Halbach configuration to shape their fields. The design involves new optics for the linacs and remaining electromagnetic arcs, as well as new electromagnetic separators. These feed into the permanent magnet FFA arcs. We also report on ongoing studies of the dynamics of the beams, and an experiment to measure the effects of radiation on the permanent magnets.

Accelerator Physics↗
DOE OSTI2025

EMC Effect of Tritium and Helium-3 from the JLab MARATHON Experiment

Measurements of the EMC effect in the tritium and helium-3 mirror nuclei are reported. The data were obtained by the MARATHON Jefferson Lab experiment, which performed deep inelastic electron scattering from deuterium and the three-body nuclei, using a cryogenic gas target system and the high resolution spectrometers of the Hall A Facility of the Lab. The data cover the Bjorken 𝑥 range from 0.20 to 0.83, corresponding to a squared four-momentum transfer 𝑄 2 range from 2.7 to 11.9 (GeV/𝑐) 2 , and to an invariant mass 𝑊 of the final hadronic state greater than 1.84 GeV/𝑐 2 . The tritium EMC effect measurement is the first of its kind. The MARATHON experimental results are compared to results from previous measurements by DESY-HERMES and JLab–Hall C experiments, as well as with few-body theoretical predictions.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Analysis of limited coverage effects on areal density measurements in inertial confinement fusion implosions

Accurate diagnosis of areal density ($\textit{ρR}$) is critical for the inference of performance metrics in inertial confinement fusion implosions. One potential source of error in this diagnosis is the existence of low mode perturbations in the imploding target, which lead to asymmetries in the inference of the $\textit{ρR}$ from different lines of sight. Here, the error accrued as a result of limited coverage of the sphere due to a finite number of detectors is quantified, and the development of a forward scatter measurement from the OMEGA neutron time-of-flight detectors is motivated. In this work, a method by which the 1D-equivalent 4 π-averaged $\langleρR\rangle$ can be reconstructed, if accurate mode information can be diagnosed by other means, is validated.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2024

Measuring the molecular Migdal effect with neutron scattering on diatomic gases

The Migdal effect is a key inelastic signal channel which could be used to detect low-mass dark matter, but it has never been observed experimentally using Standard Model probes. Here we propose a conceptual design for an experiment which could detect the Migdal effect in diatomic molecules through low-energy neutron scattering, and we provide the requirements on the beam spectrum and reducible backgrounds such that a detection may be achieved. The enhancement of the Migdal rate through non-adiabatic couplings, which are absent in isolated atoms, combined with the distinctive photon energies of electronic transitions in CO, suggest that a positive detection of the molecular Migdal effect may be possible with modest beam times at existing neutron facilities. Published by the American Physical Society 2024

74 ATOMIC AND MOLECULAR PHYSICS↗
DOE OSTI2021

Interfacial Effects on Transport Coefficient Measurements in Li-ion Battery Electrolytes

Development of Li + -containing electrolytes with improved transport properties requires reliable, reproducible, and ideally low volume techniques to rigorously understand ion-transport with varying composition. Precisely measuring the complete set of transport coefficients in liquid electrolytes under battery-relevant operating conditions is difficult and the reliability of these methods are sparsely described in electrolyte transport literature. In this work, we apply a potentiostatic polarization-based transport characterization approach typically used for polymer electrolytes to liquid electrolyte systems in an attempt to fully measure all transport coefficients (conductivity, total salt diffusion coefficient, thermodynamic factor and transference number) for the model system of LiPF 6 in an ethylene carbonate—ethyl methyl carbonate (EC:EMC) mixture. Using systematic timescale and statistical analyses, we find that transport coefficients measured using potentiostatic polarization of Li-Li symmetric cells exhibit strong correlation to Li electrode interfacial resistance, indicating that such methods are probing both bulk and interfacial phenomena. This reveals a major roadblock in characterizing electrolyte systems where the interfacial resistance is significantly larger than ohmic electrolyte resistance. As a result, we find that methods that rely on potentiostatic Li metal stripping/plating do not readily result in reliable liquid electrolyte transport coefficients, unlike similar methods for solid polymer electrolytes, where interfacial resistances are typically smaller than electrolyte resistances at the elevated temperatures typically of interest for such electrolytes.

25 ENERGY STORAGE↗
DOE OSTI2020

Data for Post-Access Report: Tidal Energy Resource Characterization and Model Validation via the Assessment of Cost-effective Spatially Distributed Current Measurements from microFloat Swarms

This project evaluated how high-resolution, spatially distributed field data can be used to refine and validate site-scale hydrodynamic simulations of tidal channels. Use of such spatially-distributed field observations or site-scale hydrodynamic simulations will be needed for producing accurate predictions of tidal energy production over larger arrays of tidal turbines. The data contained in this archive includes field observations of water velocity from a series of short surveys in Agate Pass taken on August 20th, 2020 using station-keeping ADCP (acoustic doppler current profiler) measurements, drifting downward-looking ADCPs, and microFloats, gathered by researchers at APL-UW under a previous project. It also includes high-resolution hydrodynamic model runs for the site during that time generated under TEAMER support. An explanatory file (.pdf format) describes the survey and field data structure. Processed data is stored in .mat format. Survey summary: start time, number of floats, water level. microFloat data: - Cleaned data for each float in survey, - Time series of position (lat., lon.), depth (relative to surface), and horizontal velocity (u, v) Drifting ADCP data: - Cleaned data for each drifting ADCP in survey - Time series of position (lat., lon.), sample depth (relative to surface), and observed water velocity (u,v,w) Stationary ADCP data: - Cleaned data for each station-keeping data set in survey - Time series of position (lat., lon.), sample depth (relative to surface), and observed water velocity (u,v,w) FVCOM (Finite Volume Coastal Ocean Model) model outputs: Water level and velocity, as well as derived variables (e.g., power density) from the final refined model simulations for the Agate Pass subdomain. Contained in NetCDF and ASCII files for the duration of August 18th and 20th 2020 field surveys. Additional scripts for processing the data and generating the figures in the report are included.

16 TIDAL AND WAVE POWER↗
DOE OSTI2022

Processing and Archiving Camera Data Effectively for Operando Neutron Measurement of Metal Additive Manufacturing

As the name suggests, The Operando Neutron Measurement of Metal Additive Manufacturing project conducted by ORNL’s Manufacturing Demonstration Facility (MDF) is experimenting with advanced additive metal manufacturing techniques while analyzing the process using the Spallation Neutron Source’s (SNS) beamline. As part of this experiment, the MDF is seeking to employ 2 XIMEA visible light cameras and a single infrared camera to analyze and correct manufacturing in real-time. The MDF requires a solution for capturing the high-resolution data feed from the cameras with compression while preserving enough detail for their software to detect and correct errors in real time. Our solution was to develop a Robot Operating System (ROS) driver to feed the camera data into ROS. From ROS, the feed is compressed and temporarily stored locally to a stripped 4 NVMe SSD RAID array. Post-experiment, the data is transitioned to long-term storage for archival purposes.

36 MATERIALS SCIENCE↗