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All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Recent Progress in Extreme Environment Durable SiC JFET-R Integrated Circuit Technology

This work updates recent progress made by NASA Glenn Research Center on further advancement of its uniquely durable silicon carbide junction field effect transistor and resistor (SiC JFET-R) integrated circuit (IC) technology since HiTEC 2021. Key fabrication process improvements compared to earlier NASA Glenn IC prototype runs have been ascertained via extensive “back end of line” (BEOL) processing experiments conducted on practice wafers over the past two years. The resulting changes to the BEOL process flow employed in the fabrication of “Generation 12” SiC JFET-R wafers are described. The NASA Glenn SiC JFET-R IC prototype “Generation 12” chipset design realizes significantly higher complexity digital and analog integrated ICs aimed at flexibly implementing a broad variety of mission-enabling extreme-environment electronics demonstrations. SPICE simulations have verified circuit designs ranging from simple amplification of analog sensor signals up through long-duration Venus lander operations and microprocessor-based of electric motor drive.

Silicon Carbide↗
NASA NTRSDate not supplied

GOES-R GN&C Capabilities Used to Support Instrument Anomaly Investigations

The Geostationary Operational Environmental Satellite-R program (GOES-R) has launched three of the latest generation geostationary weather satellites, of which all three are now fully operational. In this paper we discuss how the robust capabilities inherent in the design have been used to address off-nominal instrument performance observed in flight, and to subsequently provide acceptable data return from two of the instruments exhibiting off-nominal performance. The primary science instrument, the Advanced Baseline Imager (ABI), performed well on GOES-16, but on GOES-17 ABI exhibited anomalous IR-channel imaging early in the mission. Unfortunately, lower than expected thermal control capability did not cool the IR detectors to the expected temperatures. This paper presents spacecraft operations undertaken to calibrate the off-nominal performance of the instrument thermal control, and to develop spacecraft operational mitigation steps to recover near-nominal instrument performance. On GOES-16, the magnetometer (MAG) instrument experienced performance that was less than expected. As part of the MAG performance investigation, an improved calibration procedure was developed that required use of the entire GOES-R performance envelope. This paper presents an overview of the performance issues and provides details on the specific accommodations implemented to help maximize science return.

Jim Chapel↗
NASA NTRS2023

Recent Progress in Extreme Environment Durable SiC JFET-R Integrated Circuit Technology

This work updates recent progress made by NASA Glenn Research Center on further advancement of its uniquely durable silicon carbide junction field effect transistor and resistor (SiC JFET-R) integrated circuit (IC) technology since HiTEC 2021. Key fabrication process improvements compared to earlier NASA Glenn IC prototype runs have been ascertained via extensive “back end of line” (BEOL) processing experiments conducted on practice wafers over the past two years. The resulting changes to the BEOL process flow employed in the fabrication of “Generation 12” SiC JFET-R wafers are described. The NASA Glenn SiC JFET-R IC prototype “Generation 12” chipset design realizes significantly higher complexity digital and analog integrated ICs aimed at flexibly implementing a broad variety of mission-enabling extreme-environment electronics demonstrations. SPICE simulations have verified circuit designs ranging from simple amplification of analog sensor signals up through long-duration Venus lander operations and microprocessor-based of electric motor drive.

Silicon Carbide↗
DOE OSTI2021

DeepGhostBusters: Using Mask R-CNN to Detect and Mask Ghosting and Scattered-Light Artifacts from Optical Survey Images

Wide-field astronomical surveys are often affected by the presence of undesirable reflections (often known as "ghosting artifacts" or "ghosts") and scattered-light artifacts. The identification and mitigation of these artifacts is important for rigorous astronomical analyses of faint and low-surface-brightness systems. However, the identification of ghosts and scattered-light artifacts is challenging due to a) the complex morphology of these features and b) the large data volume of current and near-future surveys. In this work, we use images from the Dark Energy Survey (DES) to train, validate, and test a deep neural network (Mask R-CNN) to detect and localize ghosts and scattered-light artifacts. We find that the ability of the Mask R-CNN model to identify affected regions is superior to that of conventional algorithms and traditional convolutional neural networks methods. We propose that a multi-step pipeline combining Mask R-CNN segmentation with a classical CNN classifier provides a powerful technique for the automated detection of ghosting and scattered-light artifacts in current and near-future surveys.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2022

Conversion of Resonance Parameters Between Wigner-Eisenbud R-matrix and Transition Matrix Pole Representation

The goal of this research is to develop a numerical code for translation between the current standard, Wigner-Eisenbud R-matrix parameters and a novel pole-representation of cross sections. The method follows Ducru et al. and constructs the conversion between these parametric representations of the scattering and reaction data. This pole representation, which expresses cross sections as a sum of simple poles (and their attendant residues), is examined in the context of the advantages provided by this compact, computationally efficient representation. These advantages include the ability to doppler broaden cross sections on-the-fly as well as a lower memory footprint when generating cross sections, an attractive feature to those interested in parallel GPU based Monte Carlo. Some conversion methods between R-matrix parameters and S-matrix poles have relied on curve fitting techniques. It is unknown weather these numerical methods necessarily preserve certain underlying physics properties of the standard R-matrix cross section model (such as unitarity). The direct conversion studied here aim to preserve such properties. This knowledge is of interest for future work into the generation of resonance parameter sensitivities.

CLUTCH↗
DOE OSTI2020

An Overview of R and D on Retrievability and Retrieval Technology in Germany - 20462

Retrievability is a term that is included in most radioactive waste management programs around the world. Although national definitions vary, the overall understanding of retrievability concerns the ability to recover waste packages from the repository mine after their emplacement. Different countries may implement retrievability in very different ways, ranging from a built-in reversibility into the emplacement process to the stipulation that retrievability may in no way impede passive safety in the post-closure phase. Germany takes a middle course such that retrievability in a HLW repository (repository for high level radioactive waste) may have no significant detrimental effect on passive safety. In Germany, the current siting process considers rock salt, clay rock, and crystalline rock as potential host rocks. Therefore, Research and Development (R and D) has been investigating repository concepts and retrievability in all host rocks. After introduction of retrievability in 2010, existing repository concepts were modified to facilitate retrieval. The changes made comprised, for example, equipping boreholes with steel liners, developing new technologies, and modifying existing emplacement devices. Apart from retrieval of HLW, retrieval of other wastes from underground repositories that were designed and operated without retrievability in mind, poses major technical and scientific challenges. Currently, studies are under way to investigate the feasibility and costs of partial retrieval of waste from an underground repository for hazardous and highly toxic waste in France, Stocamine. With regard to retrieval, the rock-mechanical conditions are deteriorating rapidly, so time is of the essence. In the Asse II mine in Germany, about 126,500 waste casks with low and intermediate level waste await retrieval. The repository mine suffers from difficult rock-mechanical conditions and inflow of brine, locally into emplacement areas. The Federal Company for Radioactive Waste Disposal (BGE) is legally required to retrieve all wastes from the Asse. Due to the specific challenges, R and D is needed to develop technical solutions for the safe retrieval from each of the emplacement chambers. R and D on retrievability and retrieval technology does not only address challenges in radioactive or toxic waste retrieval but may also help to germinate innovation to better master complex underground situations in general, e.g. in deep mining, tunneling, or repository construction. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2024

Benchmark Testing of Two Residential Refrigerators Using R-600a

Household refrigerators provide a convenient and safe means of food preservation and storage. More than 100 million refrigerators are used in US homes, resulting in significant primary energy consumption and carbon emissions. As a greenhouse gas with a 100-year global warming potential of 1,430, R-134a has been banned in new US domestic refrigerators and freezers since 2021, and R-600a with a global warming potential of 3 is widely employed as a working fluid in the current US household refrigerator market. In this paper, benchmark testing was conducted for two 2023 refrigerators using R-600a. Moreover, the effect of representative customer use patterns, such as door opening and warm food storage, was studied to evaluate the effect on the energy consumption of the refrigerators. These results will provide background knowledge for facilitating the integration of new technologies to achieve significantly reduced greenhouse gas emissions in future efficient refrigerators.

Gao, Zhiming↗
DOE OSTI2024

Experimentation on Finned-Tube Microchannel Heat Exchanger Incorporating Phase Change Material and R-410A

Integrating latent heat thermal energy storage, particularly phase change materials (PCM), in building heating, ventilation, air conditioning, and refrigeration (HVAC&R) systems, offers substantial benefits for peak load shifting and energy efficiency. While numerous studies explore PCM-embedded heat exchangers (PCM-HX) using single-phase heat transfer fluids, there needs to be more investigation regarding PCM-HX utilizing two-phase refrigerant flow. This gap is even more pronounced for microchannel heat exchanger (MCHX) configurations. In this study, an MCHX-based PCM-HX was built and tested to analyze and evaluate the performance of a PCM-HX operating with a two-phase refrigerant as the working fluid. A commercially available MCHX condenser unit was embedded with 2.6 kg of RT35 PCM and tested using R-410A as the working fluid, using an in-house test loop to control the refrigerant inlet conditions precisely. Thin and minimally invasive T-type thermocouples traced the temperature evolution along MCHX channels and tube banks. Additional larger T-type thermocouple probes at the refrigerant inlet and outlet measured the average power of the PCM-HX during condensing tests, ranging from 0.7 kW to 1.6 kW based on mass flow rates varying from 3.5 g/s to 8 g/s. This experimental study on MCHX-based PCM-HX with a two-phase refrigerant has the potential to offer practical design guidelines for the direct integration of PCM-TES in HVAC&R systems without the use of a secondary loop, while caution is advised to avoid a substantial increase in the refrigerant charge amount.

42 ENGINEERING↗
DOE OSTI2023

Summary of Expansions and Updates in R&D GREET ® 2023

The Greenhouse gases, Regulated Emissions, and Energy use in Technologies (GREET®) model was developed by Argonne National Laboratory (Argonne) with the support of the U.S. Department of Energy (DOE) and other federal agencies. R&D GREET is a life cycle analysis (LCA) model, structured to systematically examine the energy and environmental effects of a wide variety of transportation fuels and vehicle technologies in major transportation sectors (i.e., road, air, marine, and rail), other end-use sectors, and energy systems. Argonne has expanded and updated the model in various areas in R&D GREET 2023. This report provides a summary of the expansions and updates.

33 ADVANCED PROPULSION SYSTEMS↗
NASA NTRS1989

The outer R Aquarii nebula - Comparison of 6 centimeter radio continuum and Balmer line emission

The 6 cm radio continuum structure of the R Aquarii outer nebula is compared with CCD imagery of H-alpha and H-beta line emission. It is shown that the 6 cm VLA imagery is morphologically similar and quantitatively related spatially to Balmer line imagery. There is negligible interstellar or circumstellar absorption along the line of sight to the outer nebula. The 6 cm structure of the outer nebula is consistent with thermal bremsstrahlung emission by a hot, optically thin gas. Spectra of the outer R Aquarii nebula are suggestive of shock-wave heating. The approximate equality of mass loss and radiative cooling suggests that the system's wind is probably enough to power the outer nebula and may account for its long-term persistence.

Hollis, J. M.↗
NASA NTRS1990

Symmetrical jet action in the R Aquarii binary system

Collimated mass flow in opposite directions is detected in the R Aqr binary-system jet by means of high-resolution long-slit spectroscopy of several optical emission lines. Also presented are images of the jet structure in the forbidden line of O III, which clearly show bipolar symmetry extending to distances of about 2750 AU on either side of the central Mira variable. The Mira light was greatly reduced by utilization of a vignetting disk on the window of the imaging CCD. This result confirms the recent report of morphological evidence for an R Aqr jet from the detection of bipolar radio continuum emission at 6 cm, and provides the necessary kinematical evidence to show that jet action is actually taking place.

Hollis, J. M.↗
NASA NTRS1994

Prediction of R-curves from small coupon tests

R-curves were predicted for Alclad 2024-T3 and C188-T3 sheet using the results of small-coupon Kahn tear tests in combination with two-dimensional elastic-plastic finite element stress analyses. The predictions were compared to experimental R-curves from 6.3, 16 and 60-inch wide M(T) specimens and good agreement was obtained. The method is an inexpensive alternative to wide panel testing for characterizing the fracture toughness of damage-tolerant sheet alloys. The usefulness of this approach was demonstrated by performing residual strength calculations for a two-bay crack in a representative fuselage structure. C188-T3 was predicted to have a 24 percent higher load carrying capability than 2024-T3 in this application as a result of its superior fracture toughness.

Yeh, J. R.↗
NASA NTRS1994

Magnetopause encounters in the magnetotail at distances of approximately 80 R(sub e)

The GEOTAIL satellite experienced several encounters with the magnetopause during the interval 0300 to 0600 hours on 27 October 1992 at a gsm location of (X,Y,Z) approximately (-81, -8, 7.5) R(sub e). Energetic ions of both solar wind and ionospheric origin (H(+), He(++), and O(+)) were observed streaming in the anti-solar direction on both the lobe and magnetosheath side of the plasma mantle-magnetosheath boundary, with maximum fluxes occuring at the boundary. Even though the mantle plasma had penetrated well into the lobe through convective drift, the energetic ions were observed only at the magnetopause and provided a clear signature of the boundary region. Using a measured convective drift velocity and observed ergetic particle anisotropies, we estimated that the maximum distance from GEOTAIL that the energetic ions could have been accelerated or made contact with the boundary field lines was less than 8 - 39 R(sub e), implying that both solar wind and ionospheric ions are accelerated and contact the magnetopause many tens of earth radii behind the earth. We further found that the unusual magnetopause positions encountered at this time could be explained in part by solar wind aberration effects. However additional processes (e. g., magnetospheric breathing modes, convoluted tail topologies) are required to fully explain these observations.

Williams, D. J.↗
NASA NTRS2008

Pre-Launch Algorithms and Risk Reduction in Support of the Geostationary Lightning Mapper for GOES-R and Beyond

The Geostationary Lightning Mapper (GLM) is a single channel, near-IR imager/optical transient event detector, used to detect, locate and measure total lightning activity over the full-disk as part of a 3-axis stabilized, geostationary weather satellite system. The next generation NOAA Geostationary Operational Environmental Satellite (GOES-R) series with a planned launch in 2014 will carry a GLM that will provide continuous day and night observations of lightning from the west coast of Africa (GOES-E) to New Zealand (GOES-W) when the constellation is fUlly operational. The mission objectives for the GLM are to 1) provide continuous, full-disk lightning measurements for storm warning and nowcasting, 2) provide early warning of tornadic activity, and 3) accumulate a long-term database to track decadal changes of lightning. The GLM owes its heritage to the NASA Lightning Imaging Sensor (1997-Present) and the Optical Transient Detector (1995-2000), which were developed for the Earth Observing System and have produced a combined 13 year data record of global lightning activity. Instrument formulation studies were completed in March 2007 and the implementation phase to develop a prototype model and up to four flight models is expected to be underway in the latter part of 2007. In parallel with the instrument development, a GOES-R Risk Reduction Team and Algorithm Working Group Lightning Applications Team have begun to develop the Level 2 ground processing algorithms and applications. Proxy total lightning data from the NASA Lightning Imaging Sensor on the Tropical Rainfall Measuring Mission (TRMM) satellite and regional test beds (e.g., Lightning Mapping Arrays in North Alabama and the Washington DC Metropolitan area)

Goodman, Steven J.↗
NASA NTRS2016

Initial Navigation Alignment of Optical Instruments on GOES-R

Post-launch alignment errors for the Advanced Baseline Imager (ABI) and Geospatial Lightning Mapper (GLM) on GOES-R may be too large for the image navigation and registration (INR) processing algorithms to function without an initial adjustment to calibration parameters. We present an approach that leverages a combination of user-selected image-to-image tie points and image correlation algorithms to estimate this initial launch-induced offset and calculate adjustments to the Line of Sight Motion Compensation (LMC) parameters. We also present an approach to generate synthetic test images, to which shifts and rotations of known magnitude are applied. Results of applying the initial alignment tools to a subset of these synthetic test images are presented. The results for both ABI and GLM are within the specifications established for these tools, and indicate that application of these tools during the post-launch test (PLT) phase of GOES-R operations will enable the automated INR algorithms for both instruments to function as intended.

geolocation↗
NASA NTRS2020

GJ 1252 b: A 1.2 R⊕ Planet Transiting an M3 Dwarf at 20.4 pc

We report the discovery of GJ 1252 b, a planet with a radius of 1.193 ± 0.074 R⊕ and an orbital period of 0.52 days around an M3-type star (0.381 ± 0.019 M⊕, 0.391 ± 0.020 R⊕) located 20.385 ± 0.019 pc away. We use Transiting Exoplanet Survey Satellite (TESS) data, ground-based photometry and spectroscopy, Gaia astrometry, and high angular resolution imaging to show that the transit signal seen in the TESS data must originate from a transiting planet. We do so by ruling out all false-positive scenarios that attempt to explain the transit signal as originating from an eclipsing stellar binary. Precise Doppler monitoring also leads to a tentative mass measurement of 2.09 ± 0.56 M⊕. The host star proximity, brightness (V = 12.19 mag, K = 7.92 mag), low stellar activity, and the system's short orbital period make this planet an attractive target for detailed characterization, including precise mass measurement, looking for other objects in the system, and planet atmosphere characterization.

Avi Shporer↗
DOE OSTI2022

Measurement of R = σ L / σ T and the separated longitudinal and transverse structure functions in the nucleon-resonance region

Here we report on a detailed study of longitudinal strength in the nucleon resonance region, presenting new results from inclusive electron-proton cross sections measured at Jefferson Lab Hall C in the four-momentum transfer range 0.2 < Q 2 < 5.5 GeV 2 . The data have been used to accurately perform over 170 Rosenbluth-type longitudinal/transverse separations. The precision R = $\sigma_{L} /\sigma _{T}$ data are presented here, along with the first separate values of the inelastic structure functions F 1 and F L in this regime. The resonance longitudinal component is found to be significant. With the new data, quark-hadron duality is observed above Q 2 = 1 GeV 2 in the separated structure functions independently.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2022

Promising Technologies and R&D Directions for the Future Muon Collider Detectors

Among the post-LHC generation of particle accelerators, the muon collider represents a unique machine with capability to provide very high energy leptonic collisions and to open the path to a vast and mostly unexplored physics programme. However, on the experimental side, such great physics potential is accompanied by unprecedented technological challenges, due to the fact that muons are unstable particles. Their decay products interact with the machine elements and produce an intense flux of background particles that eventually reach the detector and may degrade its performance. In this paper, we present technologies that have a potential to match the challenging specifications of a muon collider detector and outline a path forward for the future R&D efforts.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗