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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 199 records · Page 11
All sourcesNASA NTRSDOE OSTI
NASA NTRS1994

Real-time RMS active damping augmentation: Heavy and very light payload evaluations

Controls-Structures Integration Technology has been applied to the Space Shuttle Remote Manipulator System (RMS) to improve on-orbit performance. The objective was to actively damp undesired oscillatory motions of the RMS following routine payload maneuvering and Shuttle attitude control thruster firings. Simulation of active damping was conducted in the real-time, man-in-the-loop Systems Engineering Simulator at NASA's Johnson Space Center. The simulator was used to obtain qualitative and quantitative data on active damping performance from astronaut operators. Using a simulated three-axis accelerometer mounted on the RMS, 'sensed' vibration motions were used to generate joint motor commands that reduced the unwanted oscillations. Active damping of the RMS with heavy and light attached payloads was demonstrated in this study. Five astronaut operators examined the performance of active damping following operator commanded RMS maneuvers and Shuttle thruster firings. Noticeable improvements in the damping response of the RMS with the heavy, Hubble Space Telescope payload and the very light, astronaut in Manipulator Foot Restraint payload were observed. The potential of active damping to aid in precisely maneuvering payloads was deemed significant.

Demeo, Martha E.↗
DOE OSTI2024

Revealing complex subsurface dynamics with continuous seismic monitoring: Observations using distributed acoustic sensing and surface orbital vibrators during hydraulic fracturing

Understanding hydraulic fracturing is crucial to improving the stimulation of unconventional reservoirs and increasing fluid production. This study develops a novel seismic monitoring technology using distributed acoustic sensing (DAS) and surface orbital vibrators (SOV) to capture fracture seismic response and mechanical properties at high temporal intervals. We analyze continuous time-lapse vertical seismic profiling (VSP) data acquired every hour during the first nine days of treatment of an unconventional reservoir in the Austin Chalk/Eagle Field Laboratory. The VSP data contain clear seismic signals scattered from the activated fractures. The spatiotemporal changes of the fracture reflectivity revealed by the SOV/DAS data correlate well with the observations of fracture locations inferred from low-frequency DAS data. These results capture the fracture opening and closure processes, as well as highlight potential prestage activations of the fractures due to hydraulic connectivity with preexisting fracture systems. Therefore, analysis of the presented data set provides a unique opportunity to understand fracture initiation and subsequent evolution, not only in the context of unconventional resources but also in enhanced geothermal systems.

Correa, Julia↗
NASA NTRS2010

SPARCLE: Electrostatic Dust Control Tool Proof of Concept

Successful exploration of most planetary surfaces, with their impact-generated dusty regoliths, will depend on the capabilities to keep surfaces free of the performance-compromising dust. Once in contact with surfaces, whether set in motion by natural or mechanical means, regolith fines, or dust, behave like abrasive Velcro, coating surfaces, clogging mechanisms, making movement progressively more difticult, and being almost impossible to remove by mechanical mcans (brushing). The successful dust removal strategy will deal with dust dynamics resulting from interaction between Van der Waals and Coulombic forces. Here, proof of concept for an electrostatically-based concept for dust control tool is described and demonstrated. A low power focused electron beam is used in the presence of a small electrical field to increase the negative charge to mass ratio of a dusty surface until dust repulsion and attraction to a lower potential surface, acting as a dust collector, occurred. Our goal is a compact device of less than 5 kg mass and using less than 5 watts of power to be operational in less than 5 years with heritage from ionic sweepers for active spacecraft potential control (e.g ., on POLAR). Rovers could be fitted with devices that could hamess the removal of dust for sampling as part of the extended exploration process on Mercury, Mars, asteroids or outer solar system satellites, as well as the Moon.

Clark, P. E.↗
NASA NTRS1995

Overview of the effects of neutral gas releases on high-voltage sounding rocket platforms

Four recent sounding rocket experiments demonstrate that the release of neutral gas from both positively and negatively charged vechicles returns the vehicle potential to near the plasma potential. Early active experiment payloads, CHARGE-2 and Space Power Experiments Aboard Rockets 1 (SPEAR-1) observed enhanced currents from/to the vehicles during unplanned attitude thruster firings. The follow-on CHARGE-2B ad SPEAR-3 payloads directly measured the changes to the vehicle potential caused by both planned argon and unplanned nitrogen releases. The gas releases from positively charged CHARGE-2B consistently reduced the potential to 20-50 V, wheras the gas releases from negatively charged SPEAR-3 brought the potential to between -200 and -500 V. The difference in grounding levels for positively and negatively charged payloads suggests that the gas responsible for grounding is near the vehicle, within a small fraction of the sheath size.

Berg, G. A.↗
DOE OSTI2020

Identification of highly active surface iron sites on Ni(OOH) for the oxygen evolution reaction by atomic layer deposition

Atomic layer deposition (ALD) has become a versatile tool in catalysis, allowing for precise synthesis of catalysts useful for gaining fundamental understanding of complex systems. In this work, ALD was used to perform surface-directed modification of Ni(OH) 2 /Ni(OOH) electrocatalysts for the oxygen evolution reaction (OER) to elucidate the different roles of iron as a surface dopant and as iron distributed throughout the NiOOH structure. Electrochemical and material characterization of FeO x ALD-modified Ni(OH) 2 indicates that iron is deposited on the surface of Ni(OH) 2 sheets without modifying its bulk properties. Sub-monolayer amounts of iron were deposited on the surface of Ni(OH) 2 using low cycle numbers of ALD. This surface iron results in high OER activity, characteristic of Ni-Fe(OOH) catalysts. Ni(OH) 2 /Ni(OOH) catalysts modified to incorporate iron throughout the structure were prepared by depositing large cycle numbers of FeO x ALD, which results in the deposition of a Fe 2 O 3 overlayer. Corrosion of this Fe 2 O 3 overlayer during electrochemical cycling in alkaline electrolyte leads to the incorporation of iron throughout the structure of Ni(OH) 2 /Ni(OOH) while leaving some Fe at the surface. Incorporation of iron throughout the Ni(OH) 2 /Ni(OOH) structure was found to increase OER geometric activity for thick, high surface area Ni(OH) 2 /Ni(OOH) catalysts. Lastly, NiFeO x electrocatalysts synthesized fully by ALD were investigated for the OER; these catalysts demonstrated high OER activity and potential for photocatalysis applications.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
NASA NTRS2005

HEMT Frequency Doubler with Output at 300 GHz

An active frequency doubler in the form of an InP-based monolithic microwave integrated circuit (MMIC) containing a high-electron-mobility transistor (HEMT) has been demonstrated in operation at output frequencies in the vicinity of 300 GHz. This is the highestfrequency HEMT doubler reported to date, the next-highest-frequency active HEMT doubler having been previously reported to operate at 180 GHz. While the output power of this frequency doubler is less than that of a typical Schottky diode, this frequency doubler is considered an intermediate product of a continuing effort to realize the potential of active HEMT frequency doublers to operate with conversion efficiencies greater than those of passive diode frequency doublers. An additional incentive for developing active HEMT frequency doublers lies in the fact that they can be integrated with amplifiers, oscillators, and other circuitry on MMIC chips. The circuitry of the doubler MMIC (see Figure 1) features grounded coplanar waveguides. Air bridges and vias are used to make contact with the ground plane. The HEMT is biased for Class-A operation (in which current is conducted throughout each cycle of oscillation), which would ordinarily be better suited to linear amplification than to frequency doubling. Ordinarily, class-B operation (in which current is conducted during about half of each cycle of oscillation) would be more suitable for frequency doubling because of the essential nonlinearity of partial-cycle conduction. The reason for the unusual choice of class A was that computational simulations had shown that in this case, the efficiency in class B would be less than in class A. The input matching circuit of this doubler includes transmission lines that afford a good impedance match at the fundamental frequency, plus an open stub to prevent leakage of the second harmonic through the input terminals. The output circuit was designed to suppress the fundamental while providing a good match for the second harmonic.

Samoska, Lorene↗
NASA NTRS1991

Impact of active controls technology on structural integrity

This paper summarizes the findings of The Technical Cooperation Program to assess the impact of active controls technology on the structural integrity of aeronautical vehicles and to evaluate the present state-of-the-art for predicting the loads caused by a flight-control system modification and the resulting change in the fatigue life of the flight vehicle. The potential for active controls to adversely affect structural integrity is described, and load predictions obtained using two state-of-the-art analytical methods are given.

Noll, Thomas↗
NASA NTRS1987

Orbital transfer vehicle concept definition and system analysis study. Volume 4, Appendix A: Space station accommodations. Revision 1

Orbit Transfer Vehicle (OTV) processing at the space station is divided into two major categories: OTV processing and assembly operations, and support operations. These categories are further subdivided into major functional areas to allow development of detailed OTV processing procedures and timelines. These procedures and timelines are used to derive the specific space station accommodations necessary to support OTV activities. The overall objective is to limit impact on OTV processing requirements on space station operations, involvement of crew, and associated crew training and skill requirements. The operational concept maximizes use of automated and robotic systems to perform all required OTV servicing and maintenance tasks. Only potentially critical activities would require direct crew involvement or supervision. EVA operations are considered to be strictly contingency back-up to failure of the automated and robotic systems, with the exception of the initial assembly of Space-Based OTV accommodations at the space station, which will require manned involvement.

Randall, Roger M.↗
DOE OSTI2022

Residential Demand Flexibility: Modeling Occupant Behavior using Sociodemographic Predictors

Demand flexibility (DF) has the potential to increase the saturation of renewables in the grid and reduce operating costs for both utilities and customers. However, less than 8% of U.S. residential electric customers are enrolled in DF programs. A major research gap on this topic is an uneven understanding of behavioral drivers of electricity use and DF program participation at the household level. In this study, we employ machine learning models to predict residential occupant behavior in activities relevant to DF. We model occupants' extensive decisions (i.e., choice of action) and intensive behaviors (i.e., amount of time spent) during peak and off-peak time periods using the publicly available American Time Use Survey, which includes activities data for approximately 200,000 respondents. In our machine learning models, predictions for both extensive and intensive behavior fell within a +/-20% error margin at the aggregate level. We identify 13 key sociodemographic predictors of DF-related intensive behavior using LASSO inference and beta coefficient ranking. However, these top predictors differ by activity, suggesting potential scope for differential user targeting for DF events and technologies during program design. This work also contributes to understanding when and who might adopt these DF technologies based on their daily routine activities.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2024

Ternary complexes of isopentenyl phosphate kinase from Thermococcus paralvinellae reveal molecular determinants of non‐natural substrate specificity

Abstract Isopentenyl phosphate kinases (IPKs) have recently garnered attention for their central role in biocatalytic “isoprenol pathways,” which seek to reduce the synthesis of the isoprenoid precursors to two enzymatic steps. Furthermore, the natural promiscuity of IPKs toward non‐natural alkyl‐monophosphates (alkyl‐Ps) as substrates has hinted at the isoprenol pathways' potential to access novel isoprenoids with potentially useful activities. However, only a handful of IPK crystal structures have been solved to date, and even fewer of these contain non‐natural substrates bound in the active site. The current study sought to elucidate additional ternary complexes bound to non‐natural substrates using the IPK homolog fromThermococcus paralvinellae(TcpIPK). Four such structures were solved, each bound to a different non‐natural alkyl‐P and the phosphoryl donor substrate/product adenosine triphosphate (ATP)/adenosine diphosphate (ADP). As expected, the quaternary, tertiary, and secondary structures ofTcpIPK closely resembled those of IPKs published previously, and kinetic analysis of a novel alkyl‐P substrate highlighted the potentially dramatic effects of altering the core scaffold of the natural substrate. Even more interesting, though, was the discovery of a trend correlating the position of two α helices in the active site with the magnitude of an IPK homolog's reaction rate for the natural reaction. Overall, the current structures ofTcpIPK highlight the importance of continued structural analysis of the IPKs to better understand and optimize their activity with both natural and non‐natural substrates.

Biochemistry & Molecular Biology↗
NASA NTRS2009

Active Flap Control of the SMART Rotor for Vibration Reduction

Active control methodologies were applied to a full-scale active flap rotor obtained during a joint Boeing/ DARPA/NASA/Army test in the Air Force National Full-Scale Aerodynamic Complex 40- by 80-foot anechoic wind tunnel. The active flap rotor is a full-scale MD 900 helicopter main rotor with each of its five blades modified to include an on-blade piezoelectric actuator-driven flap with a span of 18% of radius, 25% of chord, and located at 83% radius. Vibration control demonstrated the potential of active flaps for effective control of vibratory loads, especially normal force loads. Active control of normal force vibratory loads using active flaps and a continuous-time higher harmonic control algorithm was very effective, reducing harmonic (1-5P) normal force vibratory loads by 95% in both cruise and approach conditions. Control of vibratory roll and pitch moments was also demonstrated, although moment control was less effective than normal force control. Finally, active control was used to precisely control blade flap position for correlation with pretest predictions of rotor aeroacoustics. Flap displacements were commanded to follow specific harmonic profiles of 2 deg or more in amplitude, and the flap deflection errors obtained were less than 0.2 deg r.m.s.

Hall, Steven R.↗
DOE OSTI2020

Mechanism and inhibition of Streptococcus pneumoniae IgA1 protease

Opportunistic pathogens such as Streptococcus pneumoniae secrete a giant metalloprotease virulence factor responsible for cleaving host IgA1, yet the molecular mechanism has remained unknown since their discovery nearly 30 years ago despite the potential for developing vaccines that target these enzymes to block infection. Here we show through a series of cryo-electron microscopy single particle reconstructions how the Streptococcus pneumoniae IgA1 protease facilitates IgA1 substrate recognition and how this can be inhibited. Specifically, the Streptococcus pneumoniae IgA1 protease subscribes to an active-site-gated mechanism where a domain undergoes a 10.0 Å movement to facilitate cleavage. Monoclonal antibody binding inhibits this conformational change, providing a direct means to block infection at the host interface. These structural studies explain decades of biological and biochemical studies and provides a general strategy to block Streptococcus pneumoniae IgA1 protease activity to potentially prevent infection.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS2025

Informing Planetary Protection Policies for the Future Exploration of Ceres: State of Understanding after the Dawn Mission

We review the current state of understanding of Ceres as it relates to planetary protection policy for future landed missions, including for sample return, to the dwarf planet. The Dawn mission found Ceres to be an intriguing target for a mission, with evidence for the presence of regional, possibly extensive liquid at depth, and local expressions of recent and potentially ongoing activity. The Dawn mission also found a high abundance of carbon in the regolith, interpreted as a mix of carbonates and amorphous carbon, as well as locally high concentrations of organic matter. Key findings from this review are as follows: (1) outside of the region of Occator crater, Ceres shows no geological evidence for conduits from the surface to the interior; and (2) considering the biological potential of Ceres’ deep interior, a surface sample return mission should be considered Category V restricted, unless it can be demonstrated that evaporites sourced from Ceres’ deep brine region, and recently exposed in Occator crater, have not been scattered to the rest of Ceres’ surface; in that case, the probability of returning an unsterilized particle to an acceptably low value is to be determined by a future study. Key Words: Ceres—Planetary protection—Brines—Future missions.

Julie Castillo-Rogez↗
DOE OSTI2023

Revolutionizing Lithium Storage Capabilities in TiO 2 by Expanding the Redox Range

TiO 2 is a widely recognized intercalation anode material for lithium-ion batteries (LIBs), yet its practical capacity is kinetically constrained due to sluggish lithium-ion diffusion, leading to a lithiation number of less than 1.0 Li + (336 mAh g -1 ). Here, the growth of TiO 2 crystallites is restrained by integrating Si into the TiO 2 framework, thereby enhancing the charge transfer and creating additional active sites potentially residing at grain boundaries for Li + storage. This strategy is corroborated by the expanded redox range of Ti, as thoroughly demonstrated via synchrotron radiation-based X-ray spectroscopy and Cs-corrected electron microscopy. Consequently, when deployed for lithium storage, the tailored material achieves an extraordinarily high reversible capacity of 559 mAh g -1 , 116% of the theoretical maximum of 483 mAh g -1 calculated based on all active species, while simultaneously retaining superior rate capability and robust cycling stability. Further, this work offers fresh perspectives on the revitalization of traditional electrode materials to achieve enhanced capacities.

25 ENERGY STORAGE↗
NASA NTRSDate not supplied

Assessing the Viability of Using GEOS-Forecast Product for Landslides Forecasting: A Step Toward Early Warning System

Landslides across the globe are mostly triggered by extreme rainfall events affecting infrastructure, transportation and livelihoods. The risks are rarely quantified due to lack of data, analytical skills and limited modeling techniques. Knowledge of local to global scale landslide risks provides communities and national agencies the ability to adapt disaster management practices to mitigate and recover from these hazards. In order to minimize the risks and improve characterization of community resilience to landslides, it is vital to have reliable information about the factors triggering landslides such as rainfall, well ahead in time. Forecasting potential landslide activity and impacts can be achieved through reliable precipitation forecast models. However, it is challenging because of the temporal and spatial variability of precipitation, an important factor in triggering landslides. Evaluation of the precipitation field, associated errors, and sampling uncertainties is integral for development of efficient and reliable landslide forecasting and early warning system. This study develops a methodology to assess the viability of using a precipitation field provided by a global model and its potential integration in the landslide forecasting system. The study focuses on the comparison between the IMERG (Integrated Multi-satellitE Retrievals for Global Precipitation Mission) and GEOS (NASA Goddard Earth Observing System)-Forecast product over contiguous United States (CONUS). GEOS model assimilates new observations every 6 hours, at 00, 06, 12, and 18 UTC. The framework is tested on the GEOS-Forecast Model initialized at 00 UTC using daily IMERG early product as reference using both categorical and continuous statistics. The categorical statistics includes the probability of detection (POD), success ratio (SR), critical success index (CSI), and the hit bias. Continuous statistics such as correlation, normalized standard deviation, and root-mean-square error are also evaluated. Overall, GEOS-Forecast precipitation field over the analysis period (~1 year) show underestimation with respect to IMERG early for the daily accumulated rainfall. However, the probability distribution function and cumulative distribution function of both show similar patterns. In terms of correlations, POD, SR, CSI, hit bias, the performance varies with respect to the rainfall threshold used.

Sana Khan↗
DOE OSTI2022

Tank Waste LDR Organics Data Summary for Sample-and-Send (Rev.1A)

The presence of organic chemicals regulated under the Resource Conservation and Recovery Act (RCRA) Land Disposal Restrictions (LDR) adds complexity to treating and disposing of the low activity fraction of Hanford tank waste if a low temperature treatment method such as grouting is used (SRNL-STI-2020-00228). The complexity arises from the fact that the baseline vitrification method is considered by the Washington State Department of Ecology (Ecology) as providing adequate thermal treatment for organics; a status not automatically extended to a lowtemperature process, such as solidifying the waste in a cementitious waste form. In addition, the Environmental Protection Agency (EPA) LDR program is intended to ensure that wastes are properly treated prior to disposal. Proper treatment makes hazardous waste less harmful to groundwater by reducing the mobility and/or toxicity of the hazardous constituents in the waste. EPA guidance indicates that stabilization/solidification of waste for organics could be considered impermissible dilution under the LDR dilution prohibition. In addition, waste storage activities at Hanford have required transferring and blending waste within the tank system and these activities have potentially altered the concentrations of the hazardous constituents. The LDR dilution prohibition found in 40 Code of Federal Regulations (CFR) 268.3 states that “… no generator, transporter, handler, or owner or operator of a treatment, storage, or disposal facility shall in any way dilute a restricted waste or the residual from treatment of a restricted waste as a substitute for adequate treatment …”. Hence, if LAW is to be treated using low temperature stabilization (such as cementation), then it is important to demonstrate both how past storage activities have contributed to the removal (by vacuum evaporation), or destruction (by in situ decomposition) of the LDR organics and how future retrieval and waste feed preparation will contribute to their removal (by filtration and ion exchange). Demonstrating these processes helps validate that cementation without additional organic treatment does not necessarily represent impermissible dilution. To aid in implementing cementitious solidification of Low Activity Waste (LAW), WRPS has been developing a regulatory and processing LDR treatment variance strategy termed “Sampleand-Send” that relies, in part, on demonstrating that in situ decomposition reactions along with historic evaporation of tank waste has destroyed or removed most of the LDR organics possibly associated with Hanford Tank Waste (SRNL-STI-2020-00582, SRNL-STI-2021-00453, SRNL-STI-2022-00391). Under the Sample-and-Send concept, Hanford tank waste would be retrieved, processed through a Tank-Side Cesium Removal-like system, and staged as a candidate feed that would then be sampled to confirm the waste acceptance criteria is met for solidification in an LAW cementitious treatment facility. If it can be shown that LDR organics are at concentrations below the waste acceptance criteria (WAC) for cementitious stabilization and have been sufficiently removed (by historic evaporation or by filtration and ion exchange during Cs removal), destroyed (by historic in situ decomposition), or are not soluble in LAW above the WAC then additional organic treatment is not needed prior to creating a cementitious final waste form and the concept of Sample-and-Send would be proposed to establish a non-rulemaking site-specific treatment variance using the specified method of treatment “STABL” to remove sampling requirements of the waste form after treatment. Waste not meeting the WAC could either be routed to the Hanford Waste Treatment and Immobilization Plant for LAW vitrification, or further processed by evaporation or chemical oxidation before solidifying in a cementitious waste form. A key component in implementing the Sample-and-Send strategy is identifying which of the 207 LDR organic compounds associated with the RCRA Part A permit application waste codes for the Double Shell Tanks (DSTs) and Single Shell Tanks (SSTs) and any applicable Underlying Hazardous Constituents (UHCs) from 40 CFR 268.48 should be considered as potentially present and thus subject to regulation. In addition, it is also necessary to understand the solubility volatility, and reactivity of these compounds in LAW to identify which of the potentially present LDR organic compounds are not soluble above regulatory levels or are likely to have been removed by historic evaporation or destroyed by in situ decomposition reactions. If there are potentially present LDR organic compounds that have not been removed or destroyed and are soluble above regulatorily significant concentrations then a treatability variance may be needed for these species to eliminate any concerns pertaining to impermissible dilution. The spreadsheet accompanying this calculation report contains the data and logic computations needed to screen the list of 207 LDR organics associated with Hanford tank waste to identify those potentially present and to indicate which compounds may need to be included in a treatability variance.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
NASA NTRSDate not supplied

TPSAS-NF1676L-14834-DND

A recent spin-off from flight deck adaptive automation research at NASA Langley Research Center is a biocybernetic invention referred to informally as MindShift. When using the MindShift technology, a person is able to play off-the-shelf Nintendo Wii games enhanced with biofeedback, which is used to improve self-regulation of physiological functioning. Therefore, the user experiences the challenge of regulating their physiological responses during gameplay in addition to the intended challenges presented in the video game. The research projects being conducted under the supervision of Dr. Alan Pope and Chad Stephens at NASA Langley Research Center examine the effects of interacting with the MindShift invention technology on subjects' self-regulation of heart rate and brainwave activity, performance in the games, performance on cognitive tasks, and subjective experience of effort (i.e., workload). The MindShift invention's effects are being compared to the effects of interacting with the games without the MindShift technology and to the effects of interacting with commercial-off-the-shelf (COTS) brain-computer interface (BCI) technology, specifically the Mattel Mind Flex and the Uncle Milton Star Wars Force Trainer. A 32-channel electroencephalograph system is used to record subjects' brainwave and electrocardiographic activity. The potential for biofeedback game system applications is wide-ranging - from a more engaging form of clinical biofeedback training to a new challenge for avid gamers. Consequently, research needs to be conducted to fully understand the effects that these new games have on a person's physiological and psychological functioning. Biocybernetic technology like MindShift developed from the idea that operators of critical systems such as aerospace systems could hone their stress management and attention skills in biofeedback-augmented leisure activities while off-the-job in order to positively affect their on-the-job performance. This human performance enhancement technology is applicable to skill training on manually controlled critical tasks, such as unmanned aerial vehicle teleoperation, thus enabling the training of cognitive skills to be concurrent with manual skills. Furthermore, this type of technology can apply to medical and clinical uses of biofeedback by serving as an additional form of clinical biofeedback training that may be particularly useful for those with ADHD.

Brittany N Neilson↗