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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 1,333 records · Page 74
All sourcesNASA NTRSDOE OSTI
NASA NTRS1989

Image-Enhancement Aid For The Partially Sighted

Digital filtering enhances ability to read and to recognize objects. Possible to construct portable vision aid by combining miniature video equipment to observe scene and display images with very-large-scale integrated circuits to implement real-time digital image-data processing. Afflicted observer views scene through magnifier to shift spatial frequencies downward and thereby improves perceived image. However, less magnification needed, larger the scene observed. Thus, one measure of effectiveness of new system is amount of magnification required with and without it. In series of tests, found 27 to 70 percent more magnification needed for afflicted observers to recognize unfiltered words than to recognize filtered words.

Lawton, T. A.↗
NASA NTRS1989

Demonstrating system for servicing satellites

NASA has initiated a program to demonstrate a Satellite Servicer System prototype in a series of flight tests with the Space Shuttle. When the commitment to an operational system has been demonstrated, it is anticipated that a variety of missions will develop that can productively use the servicing capability. Rendezvous and proximity operations contain key enabling technologies needed for an effective operational system. Guidance, navigation and control hardware and operational techniques must be integrated into the program. Supporting sensor technology may limit or enhance the capability of the system depending on its readiness. Requirements for docking the spacecraft in the system concept development and technology requirements are reviewed. Examples of the initial assessment of technology readiness and applications opportunities are discussed. The degree of autonomy is of particular interest.

Jenkins, Lyle M.↗
NASA NTRS1992

Single event phenomena: Testing and prediction

Highly integrated microelectronic devices are often used to increase the performance of satellite systems while reducing the system power dissipation, size, and weight. However, these devices are usually more susceptible to radiation than less integrated devices. In particular, the problem of sensitivity to single event upset and latchup is greatly increased as the integration level is increased. Therefore, a method for accurately evaluating the susceptibility of new devices to single event phenomena is critical to qualifying new components for use in space systems. This evaluation includes testing devices for upset or latchup and extrapolating the results of these tests to the orbital environment. Current methods for testing devices for single event effects are reviewed, and methods for upset rate prediction, including a new technique based on Monte Carlo simulation, are presented.

Kinnison, James D.↗
NASA NTRS1995

Review Of Existing Facilities: Shock Tunnels, Part of AIAA Short Course On Aerothermodynamic Facilities and Applications

This review is divided into two main sections. The first section described the various types of shock tunnel facilities - reflected shock tunnels, non-reflected shock tunnels and expansion tubes/tunnels. Driver technology is then described, followed by a discussion of the performance obtainable from various driver-driven combinations. A survey of a number of facilities is then presented. The second part of the review deals with details of the operation of the facilities. Operation of combustion drivers, electrically heated drivers and piston compression drivers is discussed in some detail. Main diaphragm break techniques are discussed, with particular attention being paid to maintaining the integrity of the diaphragm petals. Secondary diaphragm techniques are discussed. Phenomena which limit test time are discussed and a number of techniques to increase test time are presented. Contamination of the flow with material ablated from the wall is discussed along with the relative suitability of various materials for lining the tubes and nozzle. Finally, boundary layer effects in shock tunnels and expansion tubes are discussed.

Bogdanoff, David W.↗
NASA NTRS2011

Hardware Specific Integration Strategy for Impedance-Based Structural Health Monitoring of Aerospace Systems

The Integrated Vehicle Health Management (IVHM) Project, sponsored by NASA's Aeronautics Research Mission Directorate, is conducting research to advance the state of highly integrated and complex flight-critical health management technologies and systems. An effective IVHM system requires Structural Health Monitoring (SHM). The impedance method is one such SHM technique for detection and monitoring complex structures for damage. This position paper on the impedance method presents the current state of the art, future directions, applications and possible flight test demonstrations.

Owen, Robert B.↗
NASA NTRS2009

RAPID: Collaboration Results from Three NASA Centers in Commanding/Monitoring Lunar Assets

Three NASA centers are working together to address the challenge of operating robotic assets in support of human exploration of the Moon. This paper describes the combined work to date of the Ames Research Center (ARC), Jet Propulsion Laboratory (JPL) and Johnson Space Center (JSC) on a common support framework to control and monitor lunar robotic assets. We discuss how we have addressed specific challenges including time-delayed operations, and geographically distributed collaborative monitoring and control, to build an effective architecture for integrating a heterogeneous collection of robotic assets into a common work. We describe the design of the Robot Application Programming Interface Delegate (RAPID) architecture that effectively addresses the problem of interfacing a family of robots including the JSC Chariot, ARC K-10 and JPL ATHLETE rovers. We report on lessons learned from the June 2008 field test in which RAPID was used to monitor and control all of these assets. We conclude by discussing some future directions to extend the RAPID architecture to add further support for NASA's lunar exploration program.

Torres, R. Jay↗
NASA NTRSDate not supplied

NASA Progress on the Development and Qualification of a 12-kW Hall-Effect, Solar Electric Propulsion Thruster

I. Motivation and Background Beginning in 2014, the National Aeronautics and Space Administration (NASA) Space Technology Mission Directorate (STMD) began a project to increase the state of the art for the Hall-Effect Solar Electric Propulsion (SEP) technology. The resulting Advanced Electric Propulsion System (AEPS) project has developed a 12 kW Hall Current Thruster in support of the NASA mission to establish a permanent human presence in lunar orbit and to land the next American astronauts on the South Pole of the Moon. The project is led by the NASA Glenn Research Center, supported by the Jet Propulsion Laboratory and development, qualification & flight hardware all provided by L3 Harris Aerojet Rocketdyne (AR).The AEPS project has completed the development testing of a high power, solar electric propulsion Hall Current thruster that will be used on the NASA Power & Propulsion Element (PPE) of the Gateway space station. NASA initially built three Technology Development Units to understand key characteristics of the hall-effect rocket with magnetic shielding. The design led to development testing on two Engineering Test Unit Thrusters and multiple critical components. The project has begun production of the three flight thrusters and entered qualification testing at the component and thruster levels. II. Approach NASA and AR teams completed all development phases of the project, including full development and integration testing of the Engineering Model hardware, Critical Design Review, and ground test equipment validation, as well as fabrication and acceptance testing of the initial qualification thruster. Qualification and verification of the environmental and life requirements of the AEPS design was initiated in the Fall of 2023 and will be accomplished on two thruster units and using a series of component-level tests during 2024 and 2025. Environmental testing will incorporate functional reference firings, shock, vibration, and Thermal Vacuum (TVAC) testing. Life verification will assess the thruster wear and performance over the lifetime of the Gateway spacecraft. Critical component qualification tests include cathode heater, magnet coils, magnet heaters, temperature sensors, and a cathode assembly that will undergo life cycle testing on multiple units. Flight thrusters will complete assembly and acceptance testing and be delivered to the PPE program in early 2025. III. Preliminary and Anticipated Results The program has completed the acceptance testing, including dynamic testing and hot fire characterization, of the first qualification thruster. In the Fall of 2023, the program entered the environmental qualification phase for thruster testing. This paper will present an overview of the AEPS thruster project, thruster capabilities and flight design, preliminary results from the thruster acceptance and qualification testing, component life cycle testing and flight hardware status.

Clayton Kachele↗
DOE OSTI2021

Cross Section Generation Capability in Griffin

The Griffin code is a Multiphysics Object-Oriented Simulation Environment (MOOSE) based reactor multiphysics analysis application jointly developed by Idaho National Laboratory and Argonne National Laboratory. The code includes a variety of steady-state solvers for fixed-source, k-eigenvalue, adjoint, and subcritical multiplication, as well as transient solvers for point-kinetics, improved quasi-static, and spatial dynamics. The code reads multigroup cross sections in the ISOXML format generated from external deterministic or Monte Carlo cross section generation codes. The implementation of the cross section generation capability in Griffin was initiated last year by plugging in the cross section application programming interface (CSAPI) and reviewing the methodologies for treating particulate fuels. The focus this year was on improving the CSAPI integration and implementing advanced self-shielding methods for applications to advanced reactor problems with TRISO fuels. First, the process for cross section library generation was updated to accurately and rigorously produce isotopic cross section data. Second, the equivalent Dancoff factor cell method performing slowing down calculations on the fly for the resonance treatment was implemented in CSAPI to improve the accuracy of effective multigroup cross sections in the resonance energy range. Third, the iterative local spatial self-shielding method was implemented under the calculation framework of the equivalent Dancoff factor cell method to accurately deal with the double heterogeneity effect of particulate fuel. The updated CSAPI with the advanced self-shielding methods, together with the cross section libraries generated based on the improved process, were tested for pin-cell, unit-cell, and fuel assembly problems with various resonance self-shielding conditions based on very high temperature reactor, high temperature test reactor, and Empire benchmark cores, indicating that the updated CSAPI in Griffin is able to produce multigroup cross sections accurately and efficiently. We also showed that the methodology worked well for pebble bed fuel from HTR-10, but the capability still needs to be fully integrated into CSAPI. In the future, further benchmark tests will be performed for various thermal reactor core problems, including particulate fuel-based pebble bed reactors.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Antiviral discovery using sparse datasets by integrating experiments, molecular simulations, and machine learning

Computational methods have demonstrated success in identifying virucidal agents, effectively contributing to the discovery of novel virucidal molecules. In this study, we developed a machine learning (ML) model, trained on a small dataset, to predict inhibitors of human enterovirus 71 (EV71), a pathological agent that causes severe disease in children and immunocompromised adults. Despite the dataset’s limitation, comprising of only 36 compounds tested, our ML framework demonstrated significant predictive capability. Notably, experimental validation revealed that five out of the eight compounds predicted by our model from the Chinese cosmetic material list exhibited virucidal activity. The inhibitor effects displayed by the main active compounds were further confirmed by molecular dynamics simulation. This underscores the potential of our AI-driven approach to bypass data constraints in identifying active molecules against viral pathogens.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2022

Benchmarking Solid-State Batteries Containing Sulfide Separators: Effects of Electrode Composition and Stack Pressure

Integrating sulfide separators into solid-state batteries (SSBs) containing high energy cathodes typically requires one or more materials and engineering solutions including: (i) applying interfacial coatings to mitigate electrolyte decomposition, (ii) applying high stack pressures to form robust solid-solid contacts, and (iii) using alloying anodes to avoid Li dendrite formation. Despite the promise of these approaches, a lack of standardized testing protocols makes it difficult to directly compare results among different studies. To address this problem, the present work benchmarks the performance of SSBs containing β-Li 3 PS 4 (LPS) separators and composite cathodes. By systematically varying the anode/cathode composition and stack pressure, this work demonstrates that cathode design is a major bottleneck for solid-state cells cycled at low rates (<100 µA cm -2 ). Operando stack pressure measurements show that, while mechanical confinement generally promotes higher active material utilization and cycling stability, this strategy alone does not address interfacial reactivity between LPS and high voltage cathodes. Here, these results also demonstrate that stress evolution during cycling is dominated by volume changes at the Li metal anode. Finally, we show that FeS 2 cathodes with moderate operating voltages (<3 V vs Li/Li + ) exhibit superior cycling performance compared to high voltage cathodes by facilitating formation of stable cathode/electrolyte interfaces.

25 ENERGY STORAGE↗
DOE OSTI2024

Development of a Hardware-in-The-Loop Testbed for a Decentralized, Data-Driven Electric Vehicle Charging Control Algorithm

This study presents the design of an electric vehicle (EV)-grid integration (EVGI) hardware test-bed to implement smart EV charging algorithms. Here, the proposed test-bed also allows to create different grid events via flexible integration of other power hardware (e.g., controllable loads and battery energy storage systems) and test their impacts on EV charging. The design uses a real-time digital simulator to realize a complex distribution grid model with primary and secondary networks. A grid simulator physically realizes the selected nodes of the simulated grid to power an actual EV, forming a hardware-in-the-loop (HIL) test setup. The EV-grid integration is demonstrated based on the custom hardware and software implementation of the J1772 charging protocol using dSPACE MicroLabBox, operating as a custom EV Supply Equipment (EVSE). The HIL test-bed features a novel testing platform for accurate implementation and analysis of scalable charging algorithms. To this end, a data-driven, decentralized, model-free charging controller based on the Additive Increase and Multiplicative Decrease (AIMD) algorithm is presented and validated on an EV using the HIL test-bed. We tested the proposed algorithm under various case studies, and presented a comparison study with an existing droop-based, decentralized charging solution. The results showed that the EV successfully performed charging commands generated by the EVSE and regulated its charging power to effectively reduce the system loading caused by high EV penetration.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2022

Type IIB at eight derivatives: insights from Superstrings, Superfields and Superparticles

We study the non-linear structure of Type IIB eight-derivative couplings involving the metric and the complexified three-form G 3 . We show that, at the level of five-point string amplitudes, the kinematics in the maximally R-symmetry-violating sector is fully matched by standard superspace integrals and by superparticle amplitudes in M-theory on a two-torus. The latter approach is used to determine the complete effective action in this sector and to verify its invariance under SL(2, Z) duality. We further comment on the general structure of the higher-point kinematics. Compactifications to lower dimensions provide both tests for our results and the arena for their applications. We verify that K 3 reductions are fully consistent with the constraints of six-dimensional supersymmetry, and derive the four-dimensional flux scalar potential and axion kinetic terms at order (α') 3 in Calabi-Yau threefold reductions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2023

Stabilizing a Li–Mn–O Cathode by Blocking Lattice O Migration through a Nanoscale Phase Complex

Among all intercalation cathodes for Li-ion batteries, Li–Mn–O layered oxides offer the highest initial energy density at the lowest cost, due to the joint contribution from cationic and anionic redox chemistry. However, the poor cycling capability, resulting from the continuous lattice O loss at high potentials (>4.5 V), hinders practical applications. Herein, we employed phase complex engineering to obtain a new Li–Mn–O nanohybrid cathode featuring the uniform and coherent integration of layered nanodomains and spinel nanodomains. The combination of DFT calculations, synchrotron-based transmission X-ray microscopy, in situ differential electrochemical mass spectrometry, in situ synchrotron XRD, and electrochemical tests demonstrated that the O migration path in layered nanodomains was blocked by the neighboring spinel nanodomains with a higher oxygen vacancy migration energy, thus effectively suppressing the irreversible lattice O loss at high potentials and enhancing the cycling stability in both capacity and average voltage. Finally, the strategy is experimentally demonstrated to be effective and it leads to a new path for developing stable high-energy-density cathode materials.

25 ENERGY STORAGE↗
DOE OSTI2024

Twenty Years of Progress, Challenges, and Opportunities in Measuring and Understanding Soil Respiration

Abstract Soil respiration (Rs), the soil‐to‐atmosphere flux of CO 2 , is a dominant but uncertain part of the carbon cycle, even after decades of study. This review focuses on progress in understanding Rs from laboratory incubations to global estimates. We survey key developments of in situ ecosystem‐scale Rs observations and manipulations, synthesize Rs meta‐analyses and global flux estimates, and discuss the most compelling challenges and opportunities for the future. Increasingly sophisticated lab experiments have yielded insights into the interaction among heterotrophic respiration, substrate supply, and enzymatic kinetics, and extended incubation‐based analyses across space and time. Observational and manipulative field‐based experiments have used improved measurement approaches to deepen our understanding of the integrated effects of environmental change and disturbance on Rs. Freely‐available observational databases have enabled meta‐analyses and studies probing the magnitude of, and constraints on, the global Rs flux. Key challenges for the field include expanding Rs measurements, experiments, and opportunities to under‐represented communities and ecosystems; reconciling independent estimates of global respiration fluxes and trends; testing and leveraging the power of machine learning and process‐based models, both independently and in conjunction with each other; and continuing the field's tradition of using novel experiments to explore diverse mechanisms and ecosystems.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Integrated Framework of Multisource Data Fusion for Outage Location in Looped Distribution Systems

Accurate outage location is essential for expediting post-outage power restoration, minimizing outage duration, and enhancing the resilience of distribution networks. With the advent of advanced metering infrastructure, data-driven outage location methods have significantly advanced beyond traditional approaches that rely on manual inspections. However, existing methods still face critical challenges, like reliance on single-source data, limited ability to handle partially observable systems or difficulties with loop networks. To the best of our knowledge, no single approach has comprehensively addressed all of these challenges at once. To this end, this paper proposes a comprehensive multisource data fusion framework for outage locations via probabilistic graph networks. The framework consists of three key phases. First, a novel method for reconstituting distribution networks with loops is developed, transforming looped networks into multiple radial subnetworks that retain all outage causalities of the original network. Second, Bayesian network (BN) models are established for each subnetwork, integrating multiple data sources and network structures. Finally, a joint Gibbs sampling mechanism, featuring forward and backward information flow, is designed to merge data from separate BN models and maximize the utilization of limited evidence, ensuring accurate outage location identification. In conclusion, the framework was validated on two modified public test systems, and comparative studies confirmed its effectiveness.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2024

Open Call LDRD: Physically Informed Autoencoders for Galactic Redshift Regression

Physical constraints have been suggested to make neural network models more generalizable, act scientifically plausible, and be more data-efficient over unconstrained baselines. In this report, we present preliminary work on evaluating the effects of adding soft physical constraints to computer vision neural networks trained to estimate the conditional density of redshift on input galaxy images for the Sloan Digital Sky Survey. We introduce physically motivated soft constraint terms that are not implemented with differential or integral operators. We frame this work as a simple ablation study where the effect of including soft physical constraints is compared to an unconstrained baseline. We compare networks using standard point estimate metrics for photometric redshift estimation, as well as metrics to evaluate how faithful our conditional density estimate represents the probability over the ensemble of our test dataset. We find no evidence that the implemented soft physical constraints are more effective regularizers than augmentation.

97 MATHEMATICS AND COMPUTING↗
DOE OSTI2024

Computationally evaluating high-yield metabolites for sustainable aviation fuel (SAF) using machine learning

The computational tool described in this report helps identify promising biological pathways that produce SAF platform molecules (either a drop-in SAF, or a precursor that can be easily converted to a drop-in SAF). The workflow the computational tool follows first identifies possible biological pathways from a user-defined metabolite. These pathways may, or may not lead to a SAF platform molecule, thus the second step involves insilico testing of the end product of each pathway to assess whether it is, or is not, a SAF platform molecule. The identification of biological pathways performed in the first step is facilitated by linking the metabolite to a biological reaction database. Pathways are found by identifying pathways in the reaction database that include the metabolite. The computational tool includes an alternative way to find pathways. The alternative way develops a Flux Balanced Analysis (FBA), and modifying the FBA to include reactions that transform the metabolite. These modifications serve as a basis for understanding, in a semi-quantitative way, if there is an increase in the flux to desirable products. The second step, in silico testing of the end-products, is accomplished by estimating key physical properties relevant to SAF. When good models are available, we have integrated those models into the computational tool. In a few instances, we have developed our own models. In all instances, we have validated the models against available measured data. Finally, we have evaluated the effectiveness of our computational tool by genetically engineering Rhodosporidium toruloides. Validation occurred without the use of a FBA, and further validation is required.

09 BIOMASS FUELS↗
NASA NTRS1973

Wind tunnel test of the 0.010-scale space shuttle integrated vehicle in the NASA-Ames 3.5 foot hypersonic wind tunnel (IA10)

Experimental aerodynamic investigations were conducted in the NASA Ames Research Center 3.5-Foot Hypersonic Wind Tunnel on a 0.010-scale model of the space shuttle vehicle orbiter and external tank (model no. 32 0T). The purpose of the test was to evaluate the basic hypersonic stability characteristics of the external tank and orbiter and to define orbiter plume effects on aero characteristics using solid plumes. The test was conducted at angles of attack from minus 10 deg to 30 deg and angles of sideslip of minus 10 deg thru 10 deg. Six component force data and static base pressures were recorded during the test.

Fitzgerald, F. F.↗