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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 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Tansey_MICRE_AAD_lidar_cloud_and_precip_phase_V2.0_20160406_201601120

This data file contains retrievals of cloud-base and below-cloud precipitation phase base for the MICRE campaign. The retrieved base is largely based on AAD depolarization lidar measurements. BOM cloud radar (BASTA), ARM ceilometer, and U. Canterbury ceilometer data are used to locate cloud base and below-cloud precipitation. Details on the algorithm and analysis of results are given in Tansey et al. 2023 (submitted DOI: 10.22541/essoar.168394768.89694625/v1). The data is limited to the period 20160406 to 201601120 during which both AAD lidar data and BoM radar data was collected.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Adaptive anomaly detection for identifying attacks in cyber-physical systems: A systematic literature review

Modern cyberattacks in cyber-physical systems (CPS) rapidly evolve and cannot be deterred effectively with most current methods, which focus on characterizing past threats. Adaptive anomaly detection (AAD) is among the most promising techniques to detect evolving cyberattacks, with an emphasis on fast data processing and model adaptation. AAD has been researched extensively; however, to the best of our knowledge, our work is the first systematic literature review (SLR) on current research in this field. We present a comprehensive SLR, gathering 397 relevant papers and systematically analyzing 65 of them (47 research and 18 survey papers) on AAD in CPS from 2013 to November 2023. We introduce a novel taxonomy considering attack types, CPS application, learning paradigm, data management, and algorithms. Our findings show that most studies addressed either model adaptation or data processing, but rarely both simultaneously. This indicates a research gap in fully adaptive solutions. We also categorize algorithms, datasets, and attack characteristics, and summarize strengths and weaknesses across the literature. Our review provides a structured and accessible reference for researchers and practitioners, offering insights into key trends and highlighting limitations in current approaches. Finally, we outline several future research directions, including the need for integrated real-time processing and adaptive learning, explainability, and uncertainty quantification in AAD for CPS.

Adaptation↗
NASA NTRS1981

Postflight analysis of the Space Shuttle ascent air data system

An analysis of measurements recorded by the ascent air data system (AADS) located on the nose of the external tank of the Shuttle during the first flight is presented. The 30/10 deg biconic spike has five pressure ports for tracking yaw and pitch attitude, total pressure, and static pressure; comparison of AADS data with wind tunnel data allowed determination of angle of attack, angle of sideslip, Mach number, and dynamic pressure. Program goals for AADS development are reviewed, and specific design features are described. Wind tunnel test data were compared with best estimates simulations and initial flight data where possible; only wind tunnel derived Mach number predictions for time intervals 90 sec after launch are noted to deviate significantly from actual flight data.

Hillje, E. R.↗
NASA NTRS2013

Autonomous Aerobraking Development Software: Phase 2 Summary

NASA has used aerobraking at Mars and Venus to reduce the fuel required to deliver a spacecraft into a desired orbit compared to an all-propulsive solution. Although aerobraking reduces the propellant, it does so at the expense of mission duration, large staff, and DSN coverage. These factors make aerobraking a significant cost element in the mission design. By moving on-board the current ground-based tasks of ephemeris determination, atmospheric density estimation, and maneuver sizing and execution, a flight project would realize significant cost savings. The NASA Engineering and Safety Center (NESC) sponsored Phase 1 and 2 of the Autonomous Aerobraking Development Software (AADS) study, which demonstrated the initial feasibility of moving these current ground-based functions to the spacecraft. This paper highlights key state-of-the-art advancements made in the Phase 2 effort to verify that the AADS algorithms are accurate, robust and ready to be considered for application on future missions that utilize aerobraking. The advancements discussed herein include both model updates and simulation and benchmark testing. Rigorous testing using observed flight atmospheres, operational environments and statistical analysis characterized the AADS operability in a perturbed environment.

Cianciolo, Alicia D.↗
DOE OSTI2026

Higher-order interaction effects among operating conditions and feedstocks shape reactor microbiomes and fatty acid production profiles

Arrested anaerobic digestion (AAD) offers a promising route for producing fatty acids (FAs) from organic residues, yet optimal conditions for selectively generating medium-chain fatty acids (MCFAs) remain poorly defined. Here, we systematically evaluated the main and interaction effects of pH (5, 7, 9), feedstock (food waste, manure), temperature (35 and 45 °C), and inoculum source on microbiome composition and FA production. Anaerobic digester sludge and a novel bison rumen inoculum were compared. Significant higher-order interactions among operating parameters governed FA profiles and microbiome structure. Butyric acid production was driven by a three-way interaction among pH, feedstock, and temperature (p < 0.001), with maximum concentrations achieved in food waste reactors at pH 5.0 and 35 °C (1.2 ± 0.1 g L −1 with sludge and 1.1 ± 0.3 g L −1 with rumen). MCFA production exhibited significant four-way interactions (p < 0.1 to p < 0.001). At 45 °C and pH 5.0, inoculum source tuned MCFA selectivity: sludge favored pentanoic acid (0.4 ± 0.1 g L −1 ), whereas rumen favored hexanoic and heptanoic acids (up to 0.4 ± 0.2 g L −1 ). Manure reactors produced < 0.2 g L −1 MCFAs under all conditions. Genera, including Megasphaera, Prevotella, and Lactobacillus, were associated with production of specific MCFAs. PICRUSt2-based pathway predictions were consistent with MCFA production patterns and suggested a potential role for lactic acid–driven chain elongation pathways. This study provides insights into how interacting operating conditions shape AAD microbiomes, their FA profiles, and advances the trajectory of research aimed at engineering robust and controllable microbiomes for waste valorization.

09 BIOMASS FUELS↗
DOE OSTI2023

An emerging Asian aerosol dipole pattern reshapes the Asian summer monsoon and exacerbates northern hemisphere warming

Since the early 2010s, anthropogenic aerosols have started decreasing in East Asia (EA) while have continued to increase in South Asia (SA). Yet the climate impacts of this Asian aerosol dipole (AAD) pattern remain largely unknown. Using a state-of-the-art climate model, we demonstrate that the climate response is distinctly different between the SA aerosol increases and EA aerosol decreases. The SA aerosol increases lead to ~2.7 times stronger land summer precipitation change within the forced regions than the EA aerosol decreases. Contrastingly, the SA aerosol increases, within the tropical monsoon regime, produce weak and tropically confined responses, while the EA aerosol decreases yield a pronounced northern hemisphere warming aided by extratropical mean westerly and positive air-sea feedbacks over the western North Pacific. By scaling the observed instantaneous shortwave radiative forcing, we reveal that the recent AAD induces a pronounced northern hemisphere extratropical (beyond 30°N) warming (0.024 ± 0.010 °C decade -1 ), particularly over Europe (0.049 ± 0.009 °C decade -1 ). These findings highlight the importance of the pattern effect of forcings in driving global climate and have important implications for decadal prediction.

54 ENVIRONMENTAL SCIENCES↗
NASA NTRS1980

The Ascent Air Data System for the Space Shuttle

The Ascent Air Data System (AADS) consists of a biconic spike probe on the nose of the Space Shuttle External Tank. The final configuration of the AADS was selected on the basis of pressure measurement accuracy and simplification of the configuration. Wind tunnel calibrations were formulated to convert the 30 deg/10 deg spike measured pressures to the desired air data parameters for postflight analyses. Estimates of the system performance show that in general the user requirements for angle of attack and sideslip, and dynamic pressure are met or only slightly exceeded by the estimated errors.

Hillje, E. R.↗
NASA NTRS2011

Implementation and Simulation Results using Autonomous Aerobraking Development Software

An Autonomous Aerobraking software system is currently under development with support from the NASA Engineering and Safety Center (NESC) that would move typically ground-based operations functions to onboard an aerobraking spacecraft, reducing mission risk and mission cost. The suite of software that will enable autonomous aerobraking is the Autonomous Aerobraking Development Software (AADS) and consists of an ephemeris model, onboard atmosphere estimator, temperature and loads prediction, and a maneuver calculation. The software calculates the maneuver time, magnitude and direction commands to maintain the spacecraft periapsis parameters within design structural load and/or thermal constraints. The AADS is currently tested in simulations at Mars, with plans to also evaluate feasibility and performance at Venus and Titan.

Maddock, Robert W.↗
DOE OSTI2024

Descriptors of water aggregation

For this work, we rely on a total of 23 (cluster size, 8 structural, and 14 connectivity) descriptors to investigate structural patterns and connectivity motifs associated with water cluster aggregation. In addition to the cluster size n (number of molecules), the 8 structural descriptors can be further categorized into (i) one-body (intramolecular): covalent OH bond length (r OH ) and HOH bond angle (θ HOH ), (ii) two-body: OO distance (r OO ), OHO angle (θ OHO ), and HOOX dihedral angle ($\phi$ HOOX ), where X lies on the bisector of the HOH angle, (iii) three-body: OOO angle (θ OOO ), and (iv) many-body: modified tetrahedral order parameter (q) to account for two-, three-, four-, five-coordinated molecules (q m , m = 2, 3, 4, 5) and radius of gyration (R g ). The 14 connectivity descriptors are all many-body in nature and consist of the AD, AAD, ADD, AADD, AAAD, AAADD adjacencies [number of hydrogen bonds accepted (A) and donated (D) by each water molecule], Wiener index, Average Shortest Path Length, hydrogen bond saturation (% HB), and number of non-short-circuited three-membered cycles, four-membered cycles, five-membered cycles, six-membered cycles, and seven-membered cycles. We mined a previously reported database of 4 948 959 water cluster minima for (H 2 O) n , n = 3–25 to analyze the evolution and correlation of these descriptors for the clusters within 5 kcal/mol of the putative minima. It was found that r OH and % HB correlated strongly with cluster size n, which was identified as the strongest predictor of energetic stability. Marked changes in the adjacencies and cycle count were observed, lending insight into changes in the hydrogen bond network upon aggregation. A Principal Component Analysis (PCA) was employed to identify descriptor dependencies and group clusters into specific structural patterns across different cluster sizes. The results of this study inform our understanding of how water clusters evolve in size and what appropriate descriptors of their structural and connectivity patterns are with respect to system size, stability, and similarity. The approach described in this study is general and can be easily extended to other hydrogen-bonded systems.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Deep learning-based spatio-temporal fusion for high-fidelity ultra-high-speed X-ray radiography

Full-field ultra-high-speed (UHS) X-ray imaging experiments have been well established to characterize various processes and phenomena. However, the potential of UHS experiments through the joint acquisition of X-ray videos with distinct configurations has not been fully exploited. In this paper, we investigate the use of a deep learning-based spatio-temporal fusion (STF) framework to fuse two complementary sequences of X-ray images and reconstruct the target image sequence with high spatial resolution, high frame rate and high fidelity. We applied a transfer learning strategy to train the model and compared the peak signal-to-noise ratio (PSNR), average absolute difference (AAD) and structural similarity (SSIM) of the proposed framework on two independent X-ray data sets with those obtained from a baseline deep learning model, a Bayesian fusion framework and the bicubic interpolation method. The proposed framework outperformed the other methods with various configurations of the input frame separations and image noise levels. With three subsequent images from the low-resolution (LR) sequence of a four times lower spatial resolution and another two images from the high-resolution (HR) sequence of a 20 times lower frame rate, the proposed approach achieved average PSNRs of 37.57 dB and 35.15 dB, respectively. When coupled with the appropriate combination of high-speed cameras, the proposed approach will enhance the performance and therefore the scientific value of UHS X-ray imaging experiments.

deep learning↗
DOE OSTI2023

Volatile Fatty Acid Recovery from Arrested Anaerobic Digestion for the Production of Sustainable Aviation Fuel: A Review

The process of producing sustainable aviation fuel (SAF) from organic waste involves the use of volatile fatty acids (VFAs) as intermediates that are obtained via arrested anaerobic digestion (AAD) and VFA recovery. This recovery process often requires several steps, including dewatering, filtration, extraction, and purification. The recovery of VFAs is crucial for their upgrading and can pose a challenge in the production of SAF from organic waste due to high costs and compatibility issues. This review discusses various dewatering methods, including centrifuges, belt filter presses, and screw presses, and explores conditioning technologies that can improve dewatering performance. It also introduces filtration technologies, with a focus on dynamic filtration, which shows promise in addressing the issue of membrane fouling. Additionally, the review describes extraction technologies such as electrodialysis, adsorption, and liquid–liquid extraction (LLE). By providing insights into these different techniques, the review aims to contribute to the development of an integrated VFA recovery process with low carbon footprint.

09 BIOMASS FUELS↗
NASA NTRS1976

Results of test IA137 in the NASA/ARC 14 foot transonic wind tunnel of the 0.07 scale external tank forebody (model 68-T) to determine auxiliary aerodynamic data system feasibility

Tests were conducted in a 14 foot transonic wind tunnel to examine the feasibility of the auxiliary aerodynamic data system (AADS) for determining angles of attack and sideslip during boost flight. The model used was a 0.07 scale replica of the external tank forebody consisting of the nose portion and a 60 inch (full scale) cylindrical section of the ogive cylinder tangency point. The model terminated in a blunt base with a 320.0 inch diameter at external tank (ET) station 1120.37. Pressure data were obtained from five pressure orifices (one total and four statics) on the nose probe, and sixteen surface static pressure orifices along the ET forebody.

Thornton, D. E.↗
NASA NTRS1983

Advanced automotive diesel assessment program

Cummins Engine Company completed an analytical study to identify an advanced automotive (light duty) diesel (AAD) power plant for a 3,000-pound passenger car. The study resulted in the definition of a revolutionary diesel engine with several novel features. A 3,000-pound car with this engine is predicted to give 96.3, 72.2, and 78.8 MPG in highway, city, and combined highway-city driving, respectively. This compares with current diesel powered cars yielding 41.7, 35.0, and 37.7 MPG. The time for 0-60 MPH acceleration is 13.9 sec. compared to the baseline of 15.2 sec. Four technology areas were identified as crucial in bringing this concept to fruition. They are: (1) part-load preheating, (2) positive displacement compounding, (3) spark assisted diesel combustion system, and (4) piston development for adiabatic, oilless diesel engine. Marketing and planning studies indicate that an aggressive program with significant commitment could result in a production car in 10 years from the date of commencement.

Sekar, R.↗
NASA NTRS1983

Advanced Automotive Diesel Assessment Program, executive summary

The objectives of this analytical study were: to select one advanced automotive diesel engine (AAD) concept which would increase the tank mileage of a 3,000 pound passenger car from the present 35 mpg to at least 52 mpg; to identify long term component research and development work required to bring the selected concept to fruition; and to prepare a development strategy that will bring the selected concept to a prototype testing phase. Cummins Engine Company has completed this study. The selected concept is a 4 stroke cycle, direct injection, spark assisted, advanced adiabatic diesel engine with positive displacement compounding plus expander and part load air preheating. The engine does not use a liquid coolant nor liquid lubricants. It is a 4 cylinder, in-line, 77 mm bore x 77 mm stroke, 1.434 liters displacement engine weighing 300 lb, and rated at 70 BHP at 3000 rpm. Installation dimensions are 621 mm length x 589 mm width x 479 mm height (24.4 inch x 22 inch x 18.9 inch).

Source record↗
NASA NTRS1983

Long term technology development program

In the Advanced Adiabatic Development program, the following technology were identified as critical: piston development for oil-less, adiabatic engine; positive displacement compounding and charge system; experimental evaluation of the preheat concept; combustion system with positive ignition assist; and ceramic manufacturing technology. Of these five areas, ceramic manufacturing technology is the pacing item, and is already being addressed by several organizations. Therefore the four remaining areas need immediate attention. Since the lead time involved in engine development and production is long, this technology development should be done concurrently with the AAD engine development. A four year program is outlined which will simultaneously study these first four areas. This program requires two test rigs; one single cylinder adiabatic engine; and one multicylinder adiabatic turbocompound engine.

Sekar, R.↗
NASA NTRS1987

Correlation between aircraft MSS and lidar remotely sensed data on a forested wetland

Inland wetland in a portion of the Savannah River swamp forest were mapped with an overall accuracy of 88.5 percent on April 26,l985 using high resolution aircraft Daedalus AADS-1268 MSS data. In addition, data were acquired using a NASA sensor system flown along two flight lines over the Steel Creek Delta. The data were significantly correlated with in situ tree height measurements. The data were registered to the wetland classification map and correlated. Statistical analyses demonstrated that the laser derived canopy height information was significantly associated with the Steel Creek Delta wetland classes encountered along the transect (an F-value of 58.46 at the 0.0001 level of confidence). The relationship between vegetation height and vegetation type was then used to produce a three-dimensional model of the landscape which can be of value when computing biomass or canopy density in this forested wetland environment.

Jensen, John R.↗