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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 289 records · Page 16
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Anthropogenic effects on flood hazards in a hyper-arid watershed: The 2015 Atacama floods

An unprecedented precipitation event in the hyper-arid Atacama Desert of Northern Chile occurred in March 2015. Geomorphic alterations to the river channel and the coastal zone, coupled with the exceptional magnitude of the rainfall, caused catastrophic damage and loss of life. On the coast of the El Salado watershed, legacy mine tailings infilled the watershed-ocean connection, while the river channel was altered both by tailings and urbanization. The consequences of this event resulted from the coupling of anthropogenic geomorphic changes with an unusual climate event. Lack of field data, complex geomorphology and sediment loads influenced by human activity make analysing floods in these regions especially challenging. The objective of this work is to improve our understanding of the factors that control flood hazards by using numerical simulations to reconstruct the 2015 flood in El Salado. We carry out unsteady two-dimensional simulations fully coupled with the sediment concentration to identify the influence of tailing deposits, considering high-resolution data of the pre- and post-2015 flood topography. In conclusion, the results highlight the importance of specific event-based studies, using models that can help designing better strategies for climate change adaptation and risk mitigation, while providing information for risk reduction and channel restoration.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1983

Viewer Makes Radioactivity "Visible"

Battery operated viewer demonstrates feasibility of generating threedimensional visible light simulations of objects that emit X-ray or gamma rays. Ray paths are traced for two pinhold positions to show location of reconstructed image. Images formed by pinholes are converted to intensified visible-light images. Applications range from radioactivity contamination surveys to monitoring radioisotope absorption in tumors.

Yin, L. I.↗
NASA NTRS1990

HEAVENS system for software artifacts

The HEAVENS system is a workstation-based collection of software for analyzing, organizing, and viewing software artifacts. As a prototype, the system was used for visualizing source code structure, analyzing dependencies, and reconstructing to simplify maintenance. The system was also used in the early stages of software design to organize and relate design objects, maintain design documentation, and provide ready-made framework for later coding.

Matthews, Paul↗
DOE OSTI2026

Associated Particle Imaging of Neutron Inelastic Scatter: 3-D Reconstruction, Capabilities, and Challenges

Associated particle imaging (API) offers unique advantages for 3-D imaging of neutron inelastic scatter, including single-view tomographic imaging and data acquisition when access is limited to only one side of the interrogated object. However, widespread adoption of neutron inelastic scatter imaging has been impeded by several inherent challenges, most prominently spatial resolution, self-attenuation, and statistical noise. Here, in this work, the capabilities and challenges of neutron inelastic scatter imaging are investigated. Instead of focusing on a single imaging application, we identify imaging principles that hold for various neutron inelastic scatter imaging techniques. The primary challenges for 3-D imaging are characterized. The inherent spatial resolution in the time-of-flight (TOF) dimension is derived based on the known system timing resolution and scan geometry. Three reconstruction algorithms are described and demonstrated, including the introduction of modern iterative reconstruction incorporating a physics-based system model. Simulation is leveraged to demonstrate imaging capability with varying coincidence count levels and system timing resolution. An example of measured data with both back-scatter and forward-scatter detector positioning is presented. System design characteristics and their effects on image quality are identified. The imaging framework presented in this article has the potential to facilitate growth of 3-D neutron inelastic scatter API by identifying applications that are a good match for the technique and by targeting system development resources toward the requirements of a specific imaging task.

Associated particle imaging (API)↗
DOE OSTI2022

GenASiS Mathematics: Object-oriented manifolds, operations, and solvers for large-scale physics simulations (version 2)

We report GenASiS Mathematics provides modern Fortran classes furnishing extensible object-oriented functionality for the solution of fields governed by selected partial differential equations. The initial release included extensible object-oriented implementations of simple meshes and the evolution of generic conserved currents thereon. This revision - Version 2 of Mathematics - includes significant reorganization and streamlining of these classes, higher-order reconstruction by a different method, a Poisson solver, coarsening to avoid Courant time step limitations near coordinate singularities, and the offloading of computational kernels to GPUs.

97 MATHEMATICS AND COMPUTING↗
NASA NTRS1985

High-spatial-resolution studies of young stellar objects. II - A thick disk surrounding Lynds 1551, IRS 5

Heavily oversampled, small (2 arcsec) beam 2 micron maps of the region surrounding Lynds 1551, IRS 5 provide the basis for reconstructing maximum-entropy 'images' which have an effective spatial resolution of about 0.6 arcsec. These images reveal an extended, cusp-like structure surrounding IRS 5. This structure most likely results as light from IRS 5 is scattered in our direction by dust grains located in a thick disk of diameter 1000 AU. The disk is viewed nearly edge-on and has a mass in dust grains of 2 to 5 x 10 to the -5th solar masses. Its polar axis lies along the observed direction of the bipolar mass outflow inferred from molecular line observations of the L1551 cloud. It is possible that the observed infrared disk may represent the inner regions of a much larger thick-disk structure, whose shape derives from the combined effects of disk rotation and the gravitational field of IRS 5.

Strom, S. E.↗
DOE OSTI2025

STEM Ptychographic Holography of Electric and Magnetic Potentials

The development of fast an efficient direct electron imaging detectors have enabled the advancement of phase-imaging techniques in STEM such as iterative ptychography. As beneficial as these techniques are to imaging phase objects, the information recorded in the raw data is due to phase gradients across the probe, so it can be challenging to reconstruct slowly varying phase at lower spatial frequencies such as those induced by electric or magnetic potentials within the specimen. STEM holography [1,2] is an interferometric 4D-STEM technique where electrons in the beam are coherently divided into a superposition of two or more spatially separated probes which are then scanned over the specimen. For example, in a two-beam superposition, the two probes form overlapping bright field discs at the detector which then interfere (left of Fig. 1). Furthermore, if one probe passes through vacuum while the other transmits through the specimen, the resulting relative phase shift can be measured by recording shifts in the interference pattern. STEM holography is thus directly sensitive to the phase of the probe relative to the reference beam, and this phase can be measured regardless of the convergence angle of the probe, unlike single beam ptychography.

Biological Sciences↗
NASA NTRS2016

Mars 2020 Entry, Descent and Landing Instrumentation 2 (MEDLI2)

The Mars Entry Descent and Landing Instrumentation 2 (MEDLI2) sensor suite will measure aerodynamic, aerothermodynamic, and TPS performance during the atmospheric entry, descent, and landing phases of the Mars 2020 mission. The key objectives are to reduce design margin and prediction uncertainties for the aerothermal environments and aerodynamic database. For MEDLI2, the sensors are installed on both the heatshield and backshell, and include 7 pressure transducers, 17 thermal plugs, and 3 heat flux sensors (including a radiometer). These sensors will expand the set of measurements collected by the highly successful MEDLI suite, collecting supersonic pressure measurements on the forebody, a pressure measurement on the aftbody, direct heat flux measurements on the aftbody, a radiative heating measurement on the aftbody, and multiple near-surface thermal measurements on the thermal protection system (TPS) materials on both the forebody and aftbody. To meet the science objectives, supersonic pressure transducers and heat flux sensors are currently being developed and their qualification and calibration plans are presented. Finally, the reconstruction targets for data accuracy are presented, along with the planned methodologies for achieving the targets.

Aerodynamics↗
NASA NTRS2022

VLTI-MATISSE L- and N-Band Aperture-Synthesis Imaging of the Unclassified B[e] star FS Canis Majoris

Context. FS Canis Majoris (FS CMa, HD 45677) is an unclassified B[e] star surrounded by an inclined dust disk. The evolutionary stage of FS CMa is still debated. Perpendicular to the circumstellar disk, a bipolar outflow was detected. Infrared aperture-synthesis imaging provides us with a unique opportunity to study the disk structure. Aims. Our aim is to study the intensity distribution of the disk of FS CMa in the mid-infrared L and N bands. Methods. We performed aperture-synthesis imaging of FS CMa with the MATISSE instrument (Multi AperTure mid-Infrared SpectroScopic Experiment) in the low spectral resolution mode to obtain images in the L and N bands. We computed radiative transfer models that reproduce the L- and N-band intensity distributions of the resolved disks. Results. We present L- and N-band aperture-synthesis images of FS CMa reconstructed in the wavelength bands of 3.4–3.8 and 8.6–9.0 μm. In the L-band image, the inner rim region of an inclined circumstellar disk and the central object can be seen with a spatial resolution of 2.7 milliarcsec (mas). An inner disk cavity with an angular diameter of ~6 × 12 mas is resolved. The L-band disk consists of a bright northwestern (NW) disk region and a much fainter southeastern (SE) region. The images suggest that we are looking at the bright inner wall of the NW disk rim, which is on the far side of the disk. In the N band, only the bright NW disk region is seen. In addition to deriving the inclination and the inner disk radius, fitting the reconstructed brightness distributions via radiative transfer modelling allows one to constrain the innermost disk structure, in particular the shape of the inner disk rim.

techniques↗
DOE OSTI2026

Autonomous Coupler Alignment Using Position-Based Visual Servoing in a ROS 2 Framework

As robotic arms are becoming increasingly common alongside humans as collaborative robots, their high precision in motion enables tasks to be performed at significantly higher speeds with reduced disruption in the environment. The Fermi National Accelerator Laboratory is exploring this application by incorporating a UR16e from Universal Robots in a cleanroom setting during assembly of couplers to superconducting radio frequency cavities as part of the PIP-II project. The goal of the robotic assembly process is to precisely position the UR16e robot so that the coupler flange, mounted on the robot’s end-effector, is accurately aligned with and pressed against the cavity flange, requiring only final fastening by a lab technician. This thesis builds upon an initial system in which the robotic process was limited to the alignment phase using position-based visual servoing with an eye-in-hand camera to only align the coupler to the cavity with an offset distance. The objective of this thesis is to further advance autonomous robotic assembly by extending the process. To this end, the entire software framework was reconstructed, as the previous development environment posed significant challenges in modifying the software and adapting to hardware changes. The main contributions of this thesis are as follows: (i) a modular and scalable software framework based on ROS~2 was developed to facilitate performance expansion and interchangeability of software and hardware components; (ii) the desired alignment position for position-based visual servoing was parameterized to enable flexible configuration; and (iii) a methodology was developed to close the offset distance between the coupler and cavity utilizing the internal force-torque sensing capability of the UR16e, as visual feedback is not available during the offset-closing phase. The proposed autonomous robotic assembly reduces assembly time and technician involvement, thereby minimizing the risk of airborne particulate contamination, which is essential in the cleanroom setting. Moreover, the ROS~2-based framework provides a foundation for further expansion and continued advancement of robotic automation in Fermilab.

Giffen, Nickolas [Northern Illinois U.]↗
NASA NTRS2001

Optical Design of the MOSES Sounding Rocket Experiment

The Multi-Order Solar EUV Spectrograph (MOSES) is a sounding rocket payload now being developed by Montana State University in collaboration with the Goddard Space Flight Center, Lockheed Martin Advanced Technology Center, and Mullard Space Science Laboratory. The instrument utilizes a unique optical design to provide solar EUV measurements with true 2-pixel resolutions of 1.0 arcsec and 60 mA over a full two-dimensional field of view of 1056 x 528 arcsec, all at a time cadence of 10 s. This unprecedented capability is achieved by means of an objective spherical grating 100 mm in diameter, ruled at 833 gr/mm. The concave grating focuses spectrally dispersed solar radiation onto three separate detectors, simultaneously recording the zero-order as well as the plus and minus first-spectral-order images. Data analysis procedures, similar to those used in X-ray tomography reconstructions, can then disentangle the mixed spatial and spectral information recorded by the multiple detectors. A flat folding mirror permits an imaging focal length of 4.74 m to be packaged within the payload's physical length of 2.82 m. Both the objective grating and folding flat have specialized, closely matched, multilayer coatings that strongly enhance their EUV reflectance while also suppressing off-band radiation that would otherwise complicate data inversion. Although the spectral bandpass is rather narrow, several candidate wavelength intervals are available to carry out truly unique scientific studies of the outer solar atmosphere. Initial flights of MOSES, scheduled to begin in 2004, will observe a 10 Angstrom band that covers very strong emission lines characteristic of both the sun's corona (Si XI 303 Angstroms) and transition-region (He II 304 Angstroms). The MOSES program is supported by a grant from NASA's Office of Space Science.

Thomas, Roger J.↗
DOE OSTI2024

Efficient boundary-guided scanning for high-resolution X-ray ptychography

In the realm of X-ray ptychography experiments, a considerable amount of ptychography scans are typically performed within a field of view encompassing the target sample. While it is crucial to obtain overlapping scans in small increments over the region of interest for achieving high-resolution sample reconstruction, a significant number of these scans often redundantly measure the empty background within the wide field of view. To address this inefficiency, an innovative algorithm is proposed that introduces automatic guidance for data acquisition. The algorithm first directs the scan point to actively search for the object of interest within the field of view. Subsequently, it intelligently scans along the perimeter of the sample, strategically acquiring measurements exclusively within the boundary of the region of interest. By employing this approach, a reduction in the number of measurements required to obtain high-resolution reconstruction images is demonstrated, as compared with conventional raster scanning methods. Furthermore, the automatic guidance provided by the algorithm offers the added advantage of saving valuable time during the reconstruction process. Through practical implementation on real experiments, these findings showcase the efficacy of the proposed algorithm in enhancing the efficiency and accuracy of X-ray ptychography experiments. This novel approach holds immense potential for advancing sample analysis and imaging techniques in various scientific disciplines.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
NASA NTRS1993

Silhouettes - An automated three-dimensional plume visualization and tracking system for environmental monitoring

The method of silhouettes proceeds from the premise that the 3D location and shape of an arbitrary object can be approximated via the cross section of a series of conical volumes whose focal points are arranged at sites surrounding the object; the projection of each conical volume onto a picture plane at each focal point is identical to a projection of the outline of the object onto that picture plane. Attention is presently given to the use of the silhouettes method for gas plume dispersion monitoring through the 3D reconstruction of plumes from imagery acquired at strategically located stations in the plumes' path.

Cambridge, Vivien J.↗
NASA NTRS2003

Sprectroscopic and time-resolved optical methods and apparatus for imaging objects in turbed media

Method and apparatus for imaging objects in turbid media. In one embodiment, the method comprises illuminating at least a portion of the turbid medium with substantially monochromatic light of at least two wavelengths in the 600-1500 nm spectral range. A first of the at least two wavelengths is equal to a resonance wavelength for an optical property of an object in the illuminated portion of the turbid medium but is not equal to a resonance wavelength for the turbid medium. A second of the at least two wavelengths is not equal to a resonance wavelength for either the object or the turbid medium. Light emergent from the turbid medium following each of the foregoing illuminations comprises a ballistic component, a snake component and a diffuse component. A direct shadowgram image may be obtained by preferentially passing from the emergent light, following each illumination. the ballistic and snake components thereof and detecting the preferentially passed light. Alternatively, an inverse reconstruction image may be obtained by determining, following each illumination, the intensity of the diffuse component at a plurality of points in time and then using these pluralities of intensity determinations and a mathematical inversion algorithm to form an image of the object in the turbid medium. An image of the object with higher contrast and better quality may be obtained by using the ratio or difference of the images recorded with resonant light and non-resonant light.

Alfano, Robert R.↗
DOE OSTI2026

Multiphysics and Multiscale Simulation Methods for Electromagnetic Energy Assisted Fossil Fuel to Hydrogen Conversion (Final Scientific/Technical Report)

This report summarizes the technical accomplishments of the four-year research project “Multiphysics and Multiscale Simulation Methods for Electromagnetic Energy Assisted Fossil Fuel to Hydrogen Conversion” (Award No. DE-FE0032092), conducted at Howard University and the University of Houston (subawardee) from September 2021 to August 2025. The project successfully achieved all four major objectives: 1. 3D Structural Characterization – Developed 3D optical imaging and mechanical sectioning methods to characterize catalyst distribution and support morphology in nickel foam substrates. Successfully reconstructed 3D geometries and imported them into COMSOL Multiphysics for electromagnetic simulations. 2. EM Hotspot Simulation – Created all-frequency stable electromagnetic formulations and 3D nodal discontinuous Galerkin (NDG) methods for coupled electromagnetic-thermal-fluid problems in multiscale catalytic media. Demonstrated stable solutions from DC to microwave frequencies. 3. Multiphysics Coupling – Developed multiscale simulation methods coupling FEM electromagnetic solvers with thermal transport equations. Reactive molecular dynamics (ReaxFF MD) simulations were performed to investigate catalytic reaction mechanisms at the atomistic level. Demonstrated electromagnetic-thermal co-simulation capabilities for porous catalyst structures. 4. System Optimization – Designed and optimized EM-assisted catalytic systems using nickel foam and carbon foam structures, demonstrating significant temperature increases due to microwave heating. Observed and characterized plasma generation in carbon fiber catalysts. Investigated multiple reaction chamber geometries for improved microwave energy deposition. The project produced significant scientific contributions including 15+ peer-reviewed publications, trained multiple Ph.D. students and undergraduate researchers, and advanced the understanding of microwave-assisted hydrogen production from fossil fuels.

08 HYDROGEN↗
NASA NTRS1979

Holography through optically active windows

By using two orthogonally polarized reference beams, holograms can be recorded through stressed windows and the reconstructed virtual image will show no stress pattern. As shown analytically, the stress-pattern-free hologram is recordable for any polarization state of the object illumination. Hence, the more efficient nondepolarizing diffuser can be used in performing holography through stressed windows if two reference beams are used. Results are presented for a pair of machined polysulfone windows intended for use in a holographic flow-visualization setup in a single-stage-compressor test rig.

Decker, A. J.↗
NASA NTRS1984

Optical tomography for flow visualization of the density field around a revolving helicopter rotor blade

In this paper, a tomographic procedure for reconstructing the density field around a helicopter rotor blade tip from remote optical line-of-sight measurements is discussed. Numerical model studies have been carried out to investigate the influence of the number of available views, limited width viewing, and ray bending on the reconstruction. Performance is measured in terms of the mean-square error. It is found that very good reconstructions can be obtained using only a small number of views even when the width of view is smaller than the spatial extent of the object. An iterative procedure is used to correct for ray bending due to refraction associated with the sharp density gradients (shocks).

Snyder, R.↗