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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 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRSDate not supplied

Dusty Environment Classification and Testing: Dust Mitigation Slide Cleaning Material Study

During the Apollo missions many mechanisms, equipment, and surfaces were contaminated by lunar dust and often negatively affected. The methods used to clear these devices of dust proved ineffective, which led to premature failure in some cases. Systems being designed for upcoming missions to the Moon will need to address the performance degradation risk of dust contamination. Surfaces at risk include thermal control surfaces, solar cells, camera and sensor optics, seals, metal joints and tools, and space suit assemblies. To improve state of the art dust mitigation approaches, the dust mitigation team at NASA Glenn Re-search Center (GRC) explored the effects imposed on substrates during cleaning activities in the presence of lunar dust. The Uniform Dust Deposition System (UDDS) was used to conduct a study of various cleaning techniques on different substrates. Test substrates and cleaning media were selected to represent a wide range of structural and functional materials. Substrates included orthofabric, thermal radiator coating, aluminum, quartz glass, silicone rubber, aluminized Mylar, and FEP. Cleaning materials included cloth wipes, tapes, a brush, and a pliable cleaner concept. Cleaning material / substrate pairs were rated on cleaning efficiency, substrate damage, cleaning material longevity, and ease of use. The best performing cleaning method varied based on application.

dust mitigation↗
DOE OSTI2023

Using Magnetic Proximity Effects to Build Designer Quantum Materials [Slides]

The properties of naturally occurring materials are not necessarily commensurate with those needed for next-generation devices. Counter to conventional thought, we find magnetic proximity effects can be asymmetric. In fact, our experimental data and DFT calculations indicate this effect is universal, with material and heterostructure specificity being vital for predictive modeling. This work suggests routes towards rational design of device component materials via selective control over spin valley states.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Hierarchical Tactile Sensation Integration from Prosthetic Fingertips Enables Multi-Texture Surface Recognition

Multifunctional flexible tactile sensors could be useful to improve the control of prosthetic hands. To that end, highly stretchable liquid metal tactile sensors (LMS) were designed, manufactured via photolithography, and incorporated into the fingertips of a prosthetic hand. Three novel contributions were made with the LMS. First, individual fingertips were used to distinguish between different speeds of sliding contact with different surfaces. Second, differences in surface textures were reliably detected during sliding contact. Third, the capacity for hierarchical tactile sensor integration was demonstrated by using four LMS signals simultaneously to distinguish between ten complex multi-textured surfaces. Four different machine learning algorithms were compared for their successful classification capabilities: K-nearest neighbor (KNN), support vector machine (SVM), random forest (RF), and neural network (NN). The time-frequency features of the LMSs were extracted to train and test the machine learning algorithms. The NN generally performed the best at the speed and texture detection with a single finger and had a 99.2 ± 0.8% accuracy to distinguish between ten different multi-textured surfaces using four LMSs from four fingers simultaneously. The capability for hierarchical multi-finger tactile sensation integration could be useful to provide a higher level of intelligence for artificial hands.

Abd, Moaed A. (ORCID:0000000284954244)↗
NASA NTRS1986

Cytogenetic analyses of peripheral lymphocytes subjected to simulated solar flare radiation

Solar flare protons share many radiological health characteristics of the inner Van Allen Belt protons, and both types of radiation pose serious dangers to a number of missions planned. It is appropriate to evaluate crew dose determination procedures in terms of the type of radiation responsible for the major part of the projected exposure, i.e., protons in the neighborhood of 100 MeV. Monitoring chromosome abnormalities in peripheral lymphocytes is one method to determine an individual's accumulated radiation dosage. Cell culture and harvest is a relatively simple procedure and is well within the capabilities of a station health facility, but the evaluation of prepared microscopic slides is a time consuming and subjective procedure. This project is part of an effort to demonstrate the utility of automated image processing and evaluation procedures in expediting dose evaluation. The initial goal of this project is to produce a set of reference chromosome spreads produced from control lymphocytes and from lymphocytes exposed in whole blood to protons or gamma rays. The results of manual and automated aberration scoring will ultimately be compared to test for systematic differences between the two evaluation procedures and between the two radiation qualities. Proton irradiations are performed at the University of Texas Health Science Center at Houston Cyclotron Facility. Proton dosimetry is supplemented by TLD packets from and by assay of short-lived proton activation products in the irradiation blood samples.

Prichard, H. M.↗
NASA NTRS2009

X-48B Preliminary Flight Test Results

This slide presentation reviews the preliminary Flight tests of the X-48B development program. The X-48B is a blended wing body aircraft that is being used to test various features of the BWB concept. The research concerns the following: (1) Turbofan Development, (2) Intelligent Flight Control and Optimization, (3) Airdata Calibration (4) Parameter Identification (i.e., Determination of the parameters of a mathematical model of a system based on observation of the system inputs and response.)

Taylor, Brian R.↗
NASA NTRS2017

International Space Agency CIO Forum Industrial Control System (ICS) and Cyber

This briefing covers Industrial Control System (ICS) best practices for enhancing cyber protection. The briefing provides a very high-level overview of best practices currently being pursued by NASA as well as by other US government agencies such as NIST and DHS ICS-CERT. All information presented in this slide deck is publicly available and no sensitive information is provided in these slides. These slides will be used to generate discussion around best practices within the international community in the area of ICS cyber protections.

Powell, Robert↗
DOE OSTI2023

Uniaxial stress increases layer stacking disorder in calcium silicate hydrates with low calcium content

The long-term stress response of concrete is controlled by the intergrain and intragrain interactions of calcium-silicate-hydrates (C-S-H), nanocrystalline forms of tobermorites. To investigate both types of interactions, we examined the deviatoric stress response of 11 Å tobermorite powder with X-ray diffraction, finding that its layer stacking (i.e., sliding) disorder significantly increases. A similar experiment was performed on nanocrystalline C-S-H powders before and after applying a 360 MPa uniaxial stress. Layer stacking disorder (in the form of intragrain deformation) increases when there is low water content and when the basal spacing is large. We also find that grains with a smaller thickness-to-diameter aspect ratio are first to develop preferred orientation (in the form of intergrain sliding), facilitated by gel water. Furthermore, these findings show that intragrain deformations in C-S-H can occur at relatively low stresses and provide insights into the creep mechanism of C-S-H.

36 MATERIALS SCIENCE↗
NASA NTRS1980

Adhesion and friction of iron-base binary alloys in contact with silicon carbide in vacuum

Single pass sliding friction experiments were conducted with various iron base binary alloys (alloying elements were Ti, Cr, Mn, Ni, Rh, and W) in contact with a single crystal silicon carbide /0001/ surface in vacuum. Results indicate that atomic size and concentration of alloying elements play an important role in controlling adhesion and friction properties of iron base binary alloys. The coefficient of friction generally increases with an increase in solute concentration. The coefficient of friction increases linearly as the solute to iron atomic radius ratio increases or decreases from unity. The chemical activity of the alloying elements was also an important parameter in controlling adhesion and friction of alloys, as these latter properties are highly dependent upon the d bond character of the elements.

Miyoshi, K.↗
NASA NTRS1980

Adhesion, friction, and wear of binary alloys in contact with single-crystal silicon carbide

Sliding friction experiments, conducted with various iron base alloys (alloying elements are Ti, Cr, Mn, Ni, Rh and W) in contact with a single crystal silicon carbide /0001/ surface in vacuum are discussed. Results indicate atomic size misfit and concentration of alloying elements play a dominant role in controlling adhesion, friction, and wear properties of iron-base binary alloys. The controlling mechanism of the alloy properties is as an intrinsic effect involving the resistance to shear fracture of cohesive bonding in the alloy. The coefficient of friction generally increases with an increase in solute concentration. The coefficient of friction increases as the solute-to-iron atomic radius ratio increases or decreases from unity. Alloys having higher solute concentration produce more transfer to silicon carbide than do alloys having low solute concentrations. The chemical activity of the alloying element is also an important parameter in controlling adhesion and friction of alloys.

Miyoshi, K.↗
NASA NTRS1980

The adhesion, friction, and wear of binary alloys in contact with single-crystal silicon carbide

Sliding friction experiments were conducted with various iron-base alloys (alloying elements were Ti, Cr, Ni, Rh, and W) in contact with a single-crystal silicon carbide (0001) surface in vacuum. Results indicate atomic size misfit and concentration of alloying elements play a dominant role in controlling adhesion, friction, and wear properties of iron-base binary alloys. The controlling mechanism of the alloy properties is an intrinsic effect involving the resistance to shear fracture of cohesive bonding in the alloy. The coefficient of friction generally increases with an increase in solute concentration. The coefficient of friction increases as the solute-to-iron atomic radius ratio increases or decreases from unity. Alloys having higher solute concentration produce more transfer to silicon carbide than do alloys having low solute concentrations. The chemical activity of the alloying element is also an important parameter in controlling adhesion and friction of alloys.

Miyoshi, K.↗
NASA NTRS1986

Ion-Plated Soft Metallic Films Reduce Friction and Wear

Ion plating is ion-assisted or glow-discharge surface-deposition technique. In this process, ions or energetic atoms transfer energy, momentum, and charge to substrate and deposited surface film. Process controlled to modify physical characteristics of surface, subsurface chemical conditions, and surface and subsurface microstructures as well. Ion plating with such soft, thin metallic films as gold, silver, or lead has great potential for producing self-contained lubricating surfaces. Such films reduce friction, wear, and corrosion on sliding or rotating mechanical surfaces used in wide range of environments.

Spalvins, T.↗
NASA NTRS2010

Utilizing NX Advanced Simulation for NASA's New Mobile Launcher for Ares-l

This slide presentation reviews the use of NX to simulate the new Mobile Launcher (ML) for the Ares-I. It includes: a comparison of the sizes of the Saturn 5, the Space Shuttle, the Ares I, and the Ares V, with the height, and payload capability; the loads control plan; drawings of the base framing, the underside of the ML, beam arrangement, and the finished base and the origin of the 3D CAD data. It also reviews the modeling approach, meshing. the assembly Finite Element Modeling, the model summary. and beam improvements.

Brown, Christopher↗
NASA NTRS2019

Tribological Performance of PM400 Bushings in Oscillatory Sliding from 25 to 927 °C

Small bore (6.35 millimeter) bushings, made from NASA PM400 solid lubricant composite, were evaluated in oscillatory sliding contact against a nickel-based superalloy shaft. Tests were conducted in air from 25 to 900 degrees Centigrade for extended periods (1 million cycles, plus or minus 15 degrees, 1 hertz) to assess the suitability of PM400 in gas turbine and reciprocating engine exhaust gas path control valve applications. Operating torque and estimated friction was monitored throughout the test duration and wear was measured at the end of test. In general, friction, torque and wear was low. At temperatures above 600 degrees Centigrade, bushing dimensional stability was achieved via short duration pre-test furnace exposure heat treatments. Preliminary test results show that bushings made from NASA PM400 are feasible for aerospace and industrial applications.

high temperature solid lubricants↗
DOE OSTI2021

Nuclear Forensics National Frameworks [Slides]

Nuclear forensics is the examination of nuclear or other radioactive material, or of evidence contaminated with radionuclides, in the context of legal proceedings under international or national law related to nuclear security. The goal of forensic science is to discover linkages among people, places, materials, and events. Nuclear forensics is an essential component of national response plans to events involving nuclear or other radioactive materials out of regulatory control and informs prevention, detection, and response.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2022

Investigation Support Scenario-based Policy Discussion Development [Slides]

Nuclear forensics is the examination of nuclear or other radioactive material, or of evidence contaminated with radionuclides, in the context of legal proceedings under international or national law related to nuclear security. The goal of forensic science is to discover linkages among people, places, materials and events. Nuclear forensics is an essential component of national response plans to events involving nuclear or other radioactive materials out of regulatory control and informs prevention, detection and response.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2024

X-ray Security Imaging on Personal Dosimetry [Slides]

Federal regulations mandate that personal dosimetry devices — like optically stimulated luminescence (OSLs) — must be worn by all US Department of Energy (DOE) and associated radiation workers to track their occupational dose. Unfortunately, the inadvertent passage of OSLs through x-ray security scanners can compromise their validity. With the advent of high energy, advanced resolution security technology used in airports, this once insignificant issue now requires that Radiological Control (RadCon) be able to accurately discern non-occupational dose to effected OSLs. This presentation will discuss the principles, methods, and, rather surprising, models for establishing the corrective dose estimates at the Idaho National Laboratory (INL), and its implication across the DOE.

61 RADIATION PROTECTION AND DOSIMETRY↗