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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 667 records · Page 37
All sourcesNASA NTRSDOE OSTI
NASA NTRS2016

Team Update on North American Proton Facilities for Radiation Testing

In the wake of the closure of the Indiana University Cyclotron Facility (IUCF), this presentation provides an overview of the options for North American proton facilities. This includes those in use by the aerospace community as well as new additions from the cancer therapy regime. In addition, proton single event testing background is provided for understanding the criteria needed for these facilities for electronics testing.

Single event effects testing↗
NASA NTRS2016

Team Update on North American Proton Facilities for Radiation Testing

In the wake of the closure of the Indiana University Cyclotron Facility (IUCF), this presentation provides an overview of the options for North American proton facilities. This includes those in use by the aerospace community as well as new additions from the cancer therapy regime. In addition, proton single event testing background is provided for understanding the criteria needed for these facilities for electronics testing.

Cancer therapy↗
NASA NTRSDate not supplied

Adaptive Stress Testing of Trajectory Predictions in Flight Management Systems

To find failure events and their likelihoods in flight-critical systems, we investigate the use of an advanced black-box stress testing approach called adaptive stress testing. We analyze a trajectory predictor from a developmental commercial flight management system which takes as input a collection of lateral waypoints and en-route environmental conditions. Our aim is to search for failure events relating to inconsistencies in the predicted lateral trajectories. The intention of this work is to find likely failures and report them back to the developers so they can address and potentially resolve shortcomings of the system before deployment. To improve search performance, this work extends the adaptive stress testing formulation to be applied more generally to sequential decision-making problems with episodic reward by collecting the state transitions during the search and evaluating at the end of the simulated rollout. We use a modified Monte Carlo tree search algorithm with progressive widening as our adversarial reinforcement learner. The performance is compared to direct Monte Carlo simulations and to the cross-entropy method as an alternative importance sampling baseline. The goal is to find potential problems otherwise not found by traditional requirements-based testing. Results indicate that our adaptive stress testing approach finds more failures and finds failures with higher likelihood relative to the baseline approaches.

adaptive stress testing↗
NASA NTRS2021

Climate model projections from the Scenario Model Intercomparison Project (ScenarioMIP) of CMIP6

The Scenario Model Intercomparison Project (ScenarioMIP) defines and coordinates the main set of future climate projections, based on concentration-driven simulations, within the Coupled Model Intercomparison Project phase 6 (CMIP6). This paper presents a range of its outcomes by synthesizing results from the participating global coupled Earth system models. We limit our scope to the analysis of strictly geophysical outcomes: mainly global averages and spatial patterns of change for surface air temperature and precipitation. We also compare CMIP6 projections to CMIP5 results, especially for those scenarios that were designed to provide continuity across the CMIP phases, at the same time highlighting important differences in forcing composition, as well as in results. The range of future temperature and precipitation changes by the end of the century (2081–2100) encompassing the Tier 1 experiments based on the Shared Socioeconomic Pathway (SSP) scenarios (SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5) and SSP1-1.9 spans a larger range of outcomes compared to CMIP5, due to higher warming (by close to 1.5 °C) reached at the upper end of the 5 %–95 % envelope of the highest scenario (SSP5-8.5). This is due to both the wider range of radiative forcing that the new scenarios cover and the higher climate sensitivities in some of the new models compared to their CMIP5 predecessors. Spatial patterns of change for temperature and precipitation averaged over models and scenarios have familiar features, and an analysis of their variations confirms model structural differences to be the dominant source of uncertainty. Models also differ with respect to the size and evolution of internal variability as measured by individual models' initial condition ensemble spreads, according to a set of initial condition ensemble simulations available under SSP3-7.0. These experiments suggest a tendency for internal variability to decrease along the course of the century in this scenario, a result that will benefit from further analysis over a larger set of models. Benefits of mitigation, all else being equal in terms of societal drivers, appear clearly when comparing scenarios developed under the same SSP but to which different degrees of mitigation have been applied. It is also found that a mild overshoot in temperature of a few decades around mid-century, as represented in SSP5-3.4OS, does not affect the end outcome of temperature and precipitation changes by 2100, which return to the same levels as those reached by the gradually increasing SSP4-3.4 (not erasing the possibility, however, that other aspects of the system may not be as easily reversible). Central estimates of the time at which the ensemble means of the different scenarios reach a given warming level might be biased by the inclusion of models that have shown faster warming in the historical period than the observed. Those estimates show all scenarios reaching 1.5 °C of warming compared to the 1850–1900 baseline in the second half of the current decade, with the time span between slow and fast warming covering between 20 and 27 years from present. The warming level of 2 °C of warming is reached as early as 2039 by the ensemble mean under SSP5-8.5 but as late as the mid-2060s under SSP1-2.6. The highest warming level considered (5 °C) is reached by the ensemble mean only under SSP5-8.5 and not until the mid-2090s.d-2090s.

Scenario Model Intercomparison Project (ScenarioMI↗
NASA NTRSDate not supplied

Certification Considerations for Adaptive Stress Testing of Airborne Software

eduAdaptive Stress Testing (AST) has shown promise in identifying errant corner cases in complex software used in aerospace applications including Flight Management Systems (FMS). The strength of AST is performing test-based verification of complex aerospace software intensive systems at scale in simulated operational environments.Simulating and capturing the realistic operational complexities in integrated verification environments may exposeflaws in the softwareprior to field deployment, whereas the software may perform just fine to traditional requirements-basedunit and component level testing.AST can be used to test the whole system.Individual components may behave safely, but together can result in complex interactions and emergent failures, so it is important to test at the integrated system level.Motivated by the observed benefitsat the prototype proof of concept scale, this paper considers how AST may be integrated into a production workflow and used to generate objective evidence in a processthat delivers certified aerospace software.The research includes evaluation of alignment with both DO-178C and Overarching Properties(OP). The paper addresses questions such as “where should AST fit in the Plan for Software Aspects of Certification (PSAC) and Software Verification Plan (SVP), what aspects of AST do not fit, and what objectives does it satisfy?” The paper concludes that AST is in fact useful at locating errors in complex airborne application software and in doing so provides benefits to suppliers and end users. Furthermore, AST appears appropriate to add value in both DO-178Cbased and Overarching Properties based certification approaches.

certification↗
NASA NTRSDate not supplied

BurstCube: Behind the Scenes of a Do-No-Harm I&T Production

BurstCube is one of the most recent 6-U CubeSats built and developed by NASA Goddard Spaceflight Center (GSFC). As an astrophysics mission, BurstCube will be a rapid detection alert end-to-end mission system for short astrophysical gamma-ray bursts with the aim of increasing the chance of coincident detection of gamma-ray bursts. In addition, the mission is intended to augment the current fleet of gamma-ray astronomy satellites. The payload instrument includes 4 scintillator heads read out by arrays of silicon photomultipliers which will detect short astrophysical gamma-ray bursts. BurstCube provides a high field of view previously unavailable to larger missions and is intended to provide rapid alerts for follow up observations with other assets, increasing the chance of a coincident detection of an event. From the design to the integration and test phases, the project aimed to provide realistic test plans and stimulus to help verify and validate reachable areas of this innovative payload/instrument system and even spacecraft performance. Typical robust integration and test phases for space missions are unaligned with the budget and risk postures of small satellite or CubeSat missions, often designated as “Do No Harm” projects where the primary requirement is not harming the host platform or other payloads. Despite this status, CubeSats are complex missions that mix new and prior technologies. Integration and test for these missions requires responsible engineering, creative collaboration, and careful observation to deliver a reliable mission. This paper will provide an overview of the payload instrument and mission system, areas of injected automation (current and future), environmental testing results, and lessons learned during the integration and test phase.

CubeSats↗
NASA NTRS2024

NPCC4: Climate Risk and Equity—Advancing Knowledge Toward a Sustainable Future: Introduction

This Introduction to NPCC4 provides an overview of the first three NPCC Reports and contextualizes NPCC4's deliberate decision to address justice, equity, diversity, and inclusion in its collective work and in its own practices, procedures, and methods of assessment. Next, it summarizes the assessment process, including greater emphasis on sustained assessment. Finally, it introduces the NPCC4 chapters and their scope.

New York City Panel on Climate Change (NPCC)↗
DOE OSTI2020

Flow through suppressor with enhanced flow dynamics

An improved firearm suppressor is provided. The firearm suppressor generally includes a primary flow path and a secondary flow path. The primary flow path is centrally disposed within the suppressor and includes multiple internal chambers that are separated by conical baffles. The secondary flow path is helically disposed within the firearm suppressor. A diverter directs a portion of the propellant gas rearward, over a firearm barrel, before entering spiral lanes in the forward direction. The primary flow path slows the movement of propellant gas escaping through a projectile exit port, while the secondary flow path slows the movement of propellant gas escaping through a plurality of propellant gas exit ports.

42 ENGINEERING↗
DOE OSTI2021

High-speed, high-resolution electrophysiology in-vivo using conformal electronics

Provided herein are biomedical devices and methods of making and using biomedical devices for sensing and actuation applications. For example, flexible and/or stretchable biomedical devices are provided including electronic devices useful for establishing in situ conformal contact with a tissue in a biological environment. The invention includes implantable electronic devices and devices administered to the surfaces(s) of a target tissue, for example, for obtaining electrophysiology data from a tissue such as cardiac, brain tissue or skin.

Rogers, John A.↗
DOE OSTI2021

SNS Warm Linac Circulator Breakdown Considerations for the PPU Project

Multipacting in accelerating structures is a complex phenomenon about which there is much to be understood. While multipacting research efforts have primarily been focused on superconducting radio frequency (SRF) systems, normal conducting accelerating structures which have a higher thermal capacity, and a greater vacuum pressure tolerance could benefit from additional investigation. This research details multipacting simulation methods and the results of 3-D electromagnetic simulations of RF vacuum windows used on normal conducting linac (NCL) cavities. Benchmarking of the peak electric fields in these structures, benefits of material processing and possible techniques for reducing or eliminating multipacting activities are discussed.

Toby, George↗