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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 595 records · Page 33
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Investigating Electric Field and Light Induced Degradation in Perovskite Solar Cells through Nanometer-Scale Potential Imaging

Electric field and light induced degradations in perovskite solar cells were evaluated through nanometer-scale potential imaging across the device by using in-situ Kelvin probe force microscopy (KPFM). We derived the electric field profile from potential profiles at different bias voltages to evaluate the locations and quality of junctions across the device. We found relative changes in electric field peak intensity at the HTL/perovskite and perovskite/ETL interfaces upon stressing devices separately under voltage or light. KPFM results during 12-hour stress/rest cycling under electrical bias show both reversible and irreversible changes in the device's interfacial fields. We also observed change in the electric field profile between control and degraded devices after 100 hours of stress/rest cycling under light. Our results demonstrate how nanometer-scale potential imaging can be used to understand the impacts of external electric fields and light soaking on both irreversible degradation and reversible metastability in perovskite solar cells.

Kelvin probe force microscopy↗
DOE OSTI2022

A Robotics Enabled Eddy Current Testing System for Autonomous Inspection of Heat Exchanger Tubes

The objective of the project is to develop a robotics enabled eddy current testing system (REECTS) in automatic probe deployment, inspection, and data acquisition and analysis. The main functions of the REECTS are to: 1) identify geometry and locations of heat exchange tubes with assistance of an imaging recognition system; 2) precisely control the position and motion speed of ECT probes by an adaptive control system; 3) facilitate data analysis and real-time decision making for autonomous inspection assisted by machine learning algorithms.

20 FOSSIL-FUELED POWER PLANTS↗
NASA NTRSDate not supplied

Multi-Wavelength Comparison of Jupiter’s Zonal Winds During the New Horizons and Cassini Flybys

We present Jovian zonal wind speeds measured during the Cassini and New Horizons Jupiter flybys in 2000 and 2007, respectively. We performed our cloud tracking wind measurements using an automated, two-dimensional correlation imaging velocimetry technique. We analyzed all LORRI panchromatic images from the New Horizons Jupiter flyby dataset. This LORRI measurement documents the state of Jupiter’s zonal mean wind speed in 2007 and extends the historical record of Jupiter’s winds that serve as useful points of comparison for Juno observations. Among the Cassini ISS images, we analyzed the CL1CL2, CB2, UV3, BL1, BL2, GRN, RED, IR1, IR2, IR3, IR4, MT2, and MT3 filters. Our Cassini measurements provide valuable context to understand the altitudes probed by LORRI. Comparing the panchromatic LORRI measurements against past wind measurements using images captured with various narrow and wide-band camera filters is not straightforward. Because the Cassini ISS CL1CL2 “clear” filter’s performance is similar to that of LORRI, comparing CL1CL2 winds against LORRI results will help determine if the New Horizons measurements represent Jupiter’s cloud-top zonal wind speeds or if they are sensitive to different altitudes. In addition to placing our New Horizons measurements in altitudinal context, the Cassini ISS's IR4, IR2, RED, GRN, and BL1 filters are similar to those on Europa Clipper EIS camera. Wind measurements performed using those ISS filters will enable comparison to future missions, including anticipated observations to be taken by Europa Clipper.

Jupiter↗
NASA NTRSDate not supplied

Preparing for Europa Clipper Jupiter Observations: Multi-Wavelength Zonal Winds During the New Horizons and Cassini Flybys

We present Jovian zonal wind speeds measured during the Cassini and New Horizons Jupiter flybys in 2000 and 2007, respectively. We performed our cloud tracking wind measurements using an automated, two-dimensional correlation imaging velocimetry technique. We analyzed all LORRI panchromatic images from the New Horizons Jupiter flyby dataset. This LORRI measurement documents the state of Jupiter’s zonal mean wind speed in 2007 and extends the historical record of Jupiter’s winds. Among the Cassini ISS images, we processed the CL1CL2, CB2, UV3, BL1, BL2, GRN, RED, IR1, IR2, IR3, IR4, MT2, and MT3 filters. Our Cassini measurements provide valuable context to understand the altitudes probed by LORRI. Comparing the panchromatic LORRI measurements against past wind measurements using images captured with various narrow and wide-band camera filters is not straightforward. Because the Cassini ISS CL1CL2 “clear” filter’s performance is similar to that of LORRI, comparing CL1CL2 winds against LORRI results will help determine if the New Horizons measurements represent Jupiter’s cloud-top zonal wind speeds or if they are sensitive to different altitudes. In addition to placing our New Horizons measurements in altitudinal context, the Cassini ISS's IR4, IR2, RED, GRN, and BL1 filters are similar to those on Europa Clipper EIS camera. Wind measurements performed using those ISS filters will enable comparison to future missions, including anticipated observations to be taken by Europa Clipper

Jupiter↗
NASA NTRS2007

Nanoscale Subsurface Imaging of Nanocomposites via Resonant Difference-Frequency Atomic Force Ultrasonic Microscopy

A scanning probe microscope methodology, called resonant difference-frequency atomic force ultrasonic microscopy (RDF-AFUM), has been developed. The method employs an ultrasonic wave launched from the bottom of a sample while the cantilever of an atomic force microscope engages the sample top surface. The cantilever is driven at a frequency differing from the ultrasonic frequency by one of the contact resonance frequencies of the cantilever. The nonlinear mixing of the oscillating cantilever and the ultrasonic wave at the sample surface generates difference-frequency oscillations at the cantilever contact resonance. The resonance-enhanced difference-frequency signals are used to create amplitude and phase-generated images of nanoscale near-surface and subsurface features. RDF-AFUM phase images of LaRC-CP2 polyimide polymer containing embedded nanostructures are presented. A RDF-AFUM micrograph of a 12.7 micrometer thick film of LaRC-CP2 containing a monolayer of gold nanoparticles embedded 7 micrometers below the specimen surface reveals the occurrence of contiguous amorphous and crystalline phases within the bulk of the polymer and a preferential growth of the crystalline phase in the vicinity of the gold nanoparticles. A RDF-AFUM micrograph of LaRC-CP2 film containing randomly dispersed carbon nanotubes reveals the growth of an interphase region at certain nanotube-polymer interfaces.

Cantrell, Sean A.↗
DOE OSTI2023

Selective oxidation and nickel enrichment hinders the repassivation kinetics of multi-principal element alloy surfaces

Robust and sustained corrosion resistance in multi-principal element alloys (MPEA) requires rapid repassivation, i.e. regrowth of the passive layer once it is damaged or destroyed at the surface. In this study, we show that the repassivation of Al 0.1 CrCoFeNi MPEA in 0.6 M NaCl solution is hindered at pH of ~ 2.4 - 6.8 due to the formation of a Ni-enriched subsurface layer as a result of selective oxidation and dissolution of several principal elements, which can be fully restored at pH of ~ 14 from the oxidation of all principal elements. Specifically, surface characterization via X-ray photoelectron spectroscopy (XPS), high-angle annular dark-field (HAADF) imaging in scanning transmission electron microscopy (STEM), and atom probe tomography (APT), are coupled with density functional theory (DFT) calculations to determine surface composition, oxidation state, and electron work function to uncover the structural origin of the pH-dependent repassivation mechanisms. It was found that selective oxidation of Cr, Co, and Fe in the acidic to neutral solutions altered the surface composition to be significantly enriched in Ni as compared to the bulk. Once the original passive film is destroyed locally by either pitting or tribocorrosion, this altered surface composition exhibited a much poorer repassivation capability due to the increased electron work function and reduced surface reactivity at higher Ni concentration. Finally, these understandings could shed light on the future compositional design of non-equiatomic MPEAs towards sustained repassivation and corrosion resistance over a wide pH range.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Anomalously slow hot carrier cooling and insulator-to-metal transition in a photo-doped Mott insulator

Photo-doped Mott insulators can exhibit novel photocarrier transport and relaxation dynamics and non-equilibrium phases. However, time-resolved real-space imaging of these processes are still lacking. Here, we use scanning ultrafast electron microscopy (SUEM) to directly visualize the spatial-temporal evolution of photoexcited species in a spin-orbit assisted Mott insulator α-RuCl 3 . At low optical fluences, we observe extremely long hot photocarrier transport time over one nanosecond, almost an order of magnitude longer than any known values in conventional semiconductors. At higher optical fluences, we observe nonlinear features suggesting a photo-induced insulator-to-metal transition, which is unusual in a large-gap Mott insulator. Our results demonstrate the rich physics in a photo-doped Mott insulator that can be extracted from spatial-temporal imaging and showcase the capability of SUEM to sensitively probe photoexcitations in strongly correlated electron systems.

42 ENGINEERING↗
DOE OSTI2020

Implementation of a Talbot–Lau x-ray deflectometer diagnostic platform for the OMEGA EP laser

A Talbot–Lau X-ray Deflectometer (TXD) was implemented in the OMEGA EP laser facility to characterize the evolution of an irradiated foil ablation front by mapping electron densities >10 22 cm -3 by means of Moiré deflectometry. The experiment used a short-pulse laser (30–100 J, 10 ps) and a foil copper target as an x-ray backlighter source. In the first experimental tests performed to benchmark the diagnostic platform, grating survival was demonstrated and x-ray backlighter laser parameters that deliver Moiré images were described. Finally, the necessary modifications to accurately probe the ablation front through TXD using the EP-TXD diagnostic platform are discussed.

36 MATERIALS SCIENCE↗
DOE OSTI2026

An ultra-fast method for generating synthetic down-scattered neutron data for inertial confinement fusion implosions

In inertial confinement fusion experiments at the National Ignition Facility, asymmetries are probed by a variety of neutron diagnostics, including neutron imaging systems, real-time neutron activation diagnostics (RTNADs), and neutron spectrometers. It is often useful to generate synthetic data based on these diagnostics to validate and tune models. However, current methods of doing so using Monte Carlo particle tracing are time-consuming. In this paper, an ultra-fast method is presented for generating synthetic neutron images, RTNAD data, and spectrometry data using line integrals and 3D convolutions. While it does not contain as much physics as particle tracing codes, it is thousands of times faster and produces nearly identical data. This enables analysis techniques that depend on generating large amounts of synthetic data, which will prove very useful for the study of asymmetries going forward.

Deuterium↗
DOE OSTI2025

Solitons in Arbitrary Dimensions Stabilized by Photon-Mediated Interactions

We propose a scheme to generate solitons in arbitrary dimensions, in a matter-wave interferometer, without the need of quantum degeneracy. In our setting, solitons emerge by balancing the single-particle dispersion with engineered cavity-mediated exchange interactions between two wave packets, which, at the appropriate conditions, remain bound to each other and dispersion-free. For detection in thermal gases, we propose an interferometric probing scheme instead of traditional time-of-flight imaging.

cavity quantum electrodynamics↗
DOE OSTI2025

Efficient near-field ptychography reconstruction using the Hessian operator

X-ray ptychography is a powerful and robust coherent imaging method providing access to the complex object and probe (illumination). Ptychography reconstruction is typically performed using first-order methods due to their computational efficiency. Higher-order methods, while potentially more accurate, are often prohibitively expensive in terms of computation. In this study, we present a mathematical framework for reconstruction using second-order information derived from an efficient computation of the bilinear Hessian and Hessian operator. The formulation is provided for Gaussian-based models, enabling the simultaneous reconstruction of the object, probe, and object positions. Synthetic data tests, along with experimental near-field ptychography data processing, demonstrate a ten-fold reduction in computation time compared to first-order methods. The derived formulas for computing the Hessians, along with the strategies for incorporating them into optimization schemes, are well-structured and easily adaptable to various ptychography problem formulations.

Carlsson, Marcus [Lund Univ. (Sweden)] (ORCID:0000↗
DOE OSTI2025

Quantitative Nonlinear Optical Polarimetry with High Spatial Resolution

Nonlinear optical microscopy such as in the optical second-harmonic generation (SHG) modality has become a popular tool today for probing materials in the physical and biological sciences. While imaging and spectroscopy are widely used in the microscopy mode, nonlinear polarimetry, which can shed light on materials’ symmetry and microstructure, is relatively underdeveloped. This is partly because quantitative analytical modeling of the optical SHG response for anisotropic crystals and films largely assumes low-numerical aperture (NA) focusing of light, where the plane-wave approximation is sufficient. Tight focusing provides unique benefits in revealing out-of-plane polarization responses, which cannot be detected by near-plane-wave illumination at normal incidence. Here, we outline a method for quantitatively analyzing SHG polarimetry measurements obtained under high-NA focusing within a microscope geometry. Experiments and simulations of a variety of standard samples, from single crystals to thin films, are in good agreement, including measured and simulated spatial SHG maps of ferroelectric domains. A solution to the inverse problem is demonstrated, where the spatial distribution of an SHG tensor with unknown tensor coefficient magnitudes is determined by experimentally measured polarimetry. The ability to extract the out-of-plane component of the nonlinear polarization in normal incidence is demonstrated, which can be valuable for high-resolution polarimetry of 2D materials, thin films, heterostructures, and uniaxial crystals with a strong out-of-plane response.

36 MATERIALS SCIENCE↗
DOE OSTI2024

The Evolution of Galaxies and Clusters at High Spatial Resolution with Advanced X-ray Imaging Satellite (AXIS)

Stellar and black hole feedback heat and disperse surrounding cold gas clouds, launching gas flows off circumnuclear and galactic disks, producing a dynamic interstellar medium. On large scales bordering the cosmic web, feedback drives enriched gas out of galaxies and groups, seeding the intergalactic medium with heavy elements. In this way, feedback shapes galaxy evolution by shutting down star formation and ultimately curtailing the growth of structure after the peak at redshift 2–3. To understand the complex interplay between gravity and feedback, we must resolve both the key physics within galaxies and map the impact of these processes over large scales, out into the cosmic web. The Advanced X-ray Imaging Satellite (AXIS) is a proposed X-ray probe mission for the 2030s with arcsecond spatial resolution, large effective area, and low background. AXIS will untangle the interactions of winds, radiation, jets, and supernovae with the surrounding interstellar medium across the wide range of mass scales and large volumes driving galaxy evolution and trace the establishment of feedback back to the main event at cosmic noon. This white paper is part of a series commissioned for the AXIS Probe mission concept; additional AXIS white papers can be found at the AXIS website.

47 OTHER INSTRUMENTATION↗
NASA NTRS1974

Background starlight observed from Pioneer 10

The results of background starlight observations are reviewed that were obtained by the Pioneer 10 asteroid-Jupiter probe when, after passage beyond the asteroid belt, its imaging photopolarimeter observed integrated starlight and diffuse galactic light for the first time in the absence of zodiacal light. Brightnesses in the blue are presented with and without individually resolved stars for regions of the sky observed when Pioneer 10 was 4.64 astronomical units from the sun.

Weinberg, J. L.↗
NASA NTRS1974

Uranus science planning

Recommendations for a 1979 Mariner Jupiter-Uranus mission are discussed with the possibility of launching the first outer planet atmospheric entry probe. Measurement categories considered for the mission include conducting imaging experiments, observations in both the IR and UV spectral range, experiments associated with magnetic fields, plasma, charged particles, and S- and X-band occultation measurements.

Moore, J.↗
NASA NTRS1983

Titan exploration with advanced systems. A study of future mission concepts

The requirements, capabilities, and programmatic issues associated with science-intensive mission concepts for the advanced exploration of Saturn's largest satellite are assessed. The key questions to be answered by a Titan exploratory mission are: (1) the atmospheric composition; (2) the atmospheric structure; (3) the nature of the surface; and (4) the nature of the interior of Titan. Five selected mission concepts are described in terms of their design requirements. Mission hardware concepts include balloons and/or blimps which will allow both atmospheric and surface observations for a long period of time. Key aspects of performance analysis are presented. Mission profiles and cost summaries are given. Candidate payloads are identified for imaging and nonimaging orbiters, a buoyant station, a haze probe, and a penetrator.

Source record↗
NASA NTRS1986

Infrared observations of planetary atmospheres

Infrared data was obtained on planetary atmospheres which provides critical information on atmospheric structure, composition, and cloud properties in support of planetary missions such as Voyager and Galileo. Mapping of Jupiter and Saturn in thermal and reflected solar radiation is a high-priority monitoring and exploratory activity. Some of these images of Jupiter are shown. Radiation at 17.8 micrometer probes the upper tropospheric temperature structure where spatial structure bears a strong resemblance to visible and near-infrared reflected sunlight such as at 2.0 micrometer. At 7.8 micrometer, stratospheric temperatures appear to have a three-banded structure, enhancements near the magnetic poles and occasional transient features such as the equatorial filament near the right limb. Clouds or hazes are observed high in the stratosphere looking at wavelengths such as 2.2 micrometer, where gaseous opacity is very strong. Other maps examine cloud properties from thermal radiation not strongly influenced by gaseous opacity and the distribution of condensable gases, such as ammonia. Millimeter and submillimeter filtered radiometric observations were made of Jupiter, Uranus and Neptune via collaborative work. Radiometric observations of Uranus and Neptune at 21 and 32 micrometer were acquired and analyzed as well as grating array spectra in the ranges of 8 to 14 micrometer, 16 to 23 micrometer, and 18 to 32 micrometer. These showed evidence for C2H2 in the stratosphere of Uranus and C2H4 in the stratosphere of Neptune.

Orton, G. S.↗