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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 NTRS1953

Application of a Channel Design Method to High-Solidity Cascades and Tests of an Impulse Cascade with 90 Degrees of Turning

A technique is developed for the application of a channel design method to the design of high-solidity cascades with prescribed velocity distributions as a function of arc length along the blade-element profile. The technique is applied to both incompressible and subsonic compressible, nonviscous, irrotational fluid motion. For compressible flow, the ratio of specific heats is assumed equal to -1.0. An impulse cascade with 90 degree turning was designed for incompressible flow and was tested at the design angle of attack over a range of downstream Mach number from 0.2 to coke flow. To achieve good efficiency, the cascade was designed for prescribed velocities and maximum blade loading according to limitations imposed by considerations of boundary-layer separation.

Stanitz, John D↗
NASA NTRS1997

Vibrational force alters mRNA expression in osteoblasts

Serum-deprived mouse osteoblastic (MC3T3E1) cells were subjected to a vibrational force modeled by NASA to simulate a space shuttle launch (7.83 G rms). The mRNA levels for eight genes were investigated to determine the effect of vibrational force on mRNA expression. The mRNA levels of two growth-related protooncogenes, c-fos and c-myc, were up-regulated significantly within 30 min after vibration, whereas those of osteocalcin as well as transforming growth factor-beta1 were decreased significantly within 3 h after vibration. No changes were detected in the levels of beta-actin, histone H4, or cytoplasmic phospholipase A2 after vibration. No basal levels of cyclooxygenase-2 expression were detected. In addition, the extracellular concentrations of prostaglandin E2 (PGE2), a potent autocrine/paracrine growth factor in bone, were not significantly altered after vibration most likely due to the serum deprivation state of the osteoblasts. In comparison with the gravitational launch profile, vibrational-induced changes in gene expression were greater both in magnitude and number of genes activated. Taken together, these data suggest that the changes in mRNA expression are due to a direct mechanical effect of the vibrational force on the osteoblast cells and not to changes in the local PGE2 concentrations. The finding that launch forces induce gene expression is of utmost importance since many of the biological experiments do not dampen vibrational loads on experimental samples. This lack of dampening of vibrational forces may partially explain why 1-G onboard controls sometimes do not reflect 1-G ground controls. These data may also suggest that scientists use extra ground controls that are exposed to launch forces, have these forces dampened on launched samples, or use facilities such as Biorack that provide an onboard 1-G centrufuge in order to control for space shuttle launch forces.

NASA Discipline Cell Biology↗
DOE OSTI2025

Developing the Science Basis for Understanding Polymer Encapsulant Degradation Mechanisms: DuraMAT 2.0 Final Project Report

Polymeric encapsulants are essential materials in photovoltaic modules, protecting sensitive electronics from the environment while providing mechanical integrity to the multilayered assembly. However, these polymeric materials are susceptible to degradation processes driven by the ingress of environmental species, ultraviolet radiation, thermal stresses, and mechanical loading. In this study, we employ a combined atomistic simulation and accelerated aging experimental approach to study the molecular-scale mechanisms of encapsulant degradation. Classical molecular dynamics simulations quantify the diffusion of environmental and degradation species through the polymer matrix, producing composition-specific diffusion coefficients. Reactive simulations characterize activation energy barriers and reaction rate constants for key chemical pathways. In parallel, thermal-desorption analyses coupled with mass spectrometry monitor the emergence and concentration profiles of degradation products under controlled stressor conditions. By integrating simulation and experiment, we establish quantitative correlations between polymer composition, species diffusivity, and chemical reactivity. We anticipate that these relations and quantitative values could serve as high-fidelity inputs to reaction-diffusion models, enabling physics-informed lifetime predictions and guiding the design of more durable encapsulant materials for solar energy applications.

36 MATERIALS SCIENCE↗
DOE OSTI2023

The Chemical and Electronic Properties of Stability-Enhanced, Mixed Ir-TiO x Oxygen Evolution Reaction Catalysts

Iridium has emerged as the leading catalyst material for the anodic oxygen evolution reaction (OER) in acidic media. Often, iridium is mixed with more stable materials such as titanium. For these materials, the electronic structure of titanium plays a crucial role since with varying degrees of oxidation titanium transforms to semiconducting or even insulating phases. Yet, the electronic properties of mixed Ir-TiO x catalysts have never been systematically studied. In this study, we correlate the catalytic performance of mixed Ir-TiO x -based OER catalysts with the electronic structure of the surface layers. For this, a thin film material library with a 20-70 at. % Ir (Ir/[Ir + Ti]) compositional gradient was prepared. We used inductively coupled plasma mass spectrometry to test the OER activity and stability of the set of mixed Ir-TiO x catalyst candidate materials. Complementary, Ti L 2,3 - and O K-edge X-ray absorption spectroscopy and depth-dependent X-ray photoelectron spectroscopy measurements were performed to correlate the catalytic performance with the composition and electronic property profiles of these mixed Ir-TiO x OER anode catalysts. The spectroscopic analysis reveals that titanium is present as an intermixed matrix of semiconductive but stable TiO 2 , conductive but less stable titanium-suboxides (TiO x ), and highly conductive but highly unstable metallic Ti(0). The extent of the titanium oxidation strongly depends on the titanium content, with a lower degree of oxidation observed for lower titanium (and thus higher iridium) contents. For an iridium loading of 70 at. %, the respective mixed Ir-TiO x catalyst showed a similar OER activity to that of the pure metallic iridium (1.74 vs 1.59 VRHE, respectively) but with a 71% lower iridium dissolution rate relative to the pure metallic iridium. This demonstrates the stabilization effect of titanium addition while maintaining high OER activity.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

A microfabricated, 3D-sharpened silicon shuttle for insertion of flexible electrode arrays through dura mater into brain

Electrode arrays for chronic implantation in the brain are a critical technology in both neuroscience and medicine. Recently, flexible, thin-film polymer electrode arrays have shown promise in facilitating stable, single-unit recordings spanning months in rats. While array flexibility enhances integration with neural tissue, it also requires removal of the dura mater, the tough membrane surrounding the brain, and temporary bracing to penetrate the brain parenchyma. Durotomy increases brain swelling, vascular damage, and surgical time. Insertion using a bracing shuttle results in additional vascular damage and brain compression, which increase with device diameter; while a higher-diameter shuttle will have a higher critical load and more likely penetrate dura, it will damage more brain parenchyma and vasculature. One way to penetrate the intact dura and limit tissue compression without increasing shuttle diameter is to reduce the force required for insertion by sharpening the shuttle tip. We describe a novel design and fabrication process to create silicon insertion shuttles that are sharp in three dimensions and can penetrate rat dura, for faster, easier, and less damaging implantation of polymer arrays. Sharpened profiles are obtained by reflowing patterned photoresist, then transferring its sloped profile to silicon with dry etches. We demonstrate that sharpened shuttles can reliably implant polymer probes through dura to yield high quality single unit and local field potential recordings for at least 95 days. On insertion directly through dura, tissue compression is minimal. Significance. This is the first demonstration of a rat dural-penetrating array for chronic recording. This device obviates the need for a durotomy, reducing surgical time and risk of damage to the blood-brain barrier. This is an improvement to state-of-the-art flexible polymer electrode arrays that facilitates their implantation, particularly in multi-site recording experiments. This sharpening process can also be integrated into silicon electrode array fabrication.

60 APPLIED LIFE SCIENCES↗
NASA NTRS1987

Integration of altitude and airspeed information into a primary flight display via moving-tape formats

A ground-based aircraft simulation study was conducted to determine the effect on pilot performance of replacing the electromechanical altimeter and airspeed indicators with electronically generated representations integrated into the primary flight display via moving-tape (linear moving scale) formats. Several key factors relating to moving-tape formats were examined during the study: tape centering, secondary (trend) information, and tape orientation. The factor of centering refers to whether the tape was centered about the actual airspeed or altitude or about some defined reference value. Tape orientation refers to whether the values represented are arranged in either descending or ascending order. Six pilots participated in this study, with each subject performing 18 runs along a single, known flight profile. Subjective results indicated that the moving-tape formats were generally better than that of the conventional instruments. They also indicated that an actual-centered fixed pointer was preferred to a reference-centered pointer. Performance data for a visual secondary task showed that formats not containing trend information produced better performance; however, no difference was noted in airspeed tracking or altitude tracking performance. Regarding tape orientation, subjective comments indicated that there was lower work load and better performance when the airspeed tape had the high numbers at the top.

Abbott, Terence S.↗
NASA NTRS2016

Development and Evaluation of Titanium Spacesuit Bearings

The Z-2 Prototype Planetary Extravehicular Space Suit Assembly is a continuation of NASA's Z-series of spacesuits, designed with the intent of meeting a wide variety of exploration mission objectives, including human exploration of the Martian surface. Incorporating titanium bearings into the Z-series space suit architecture allows us to reduce mass by an estimated 23 lbs per suit system compared to the previously used stainless steel bearing race designs, without compromising suit functionality. There are two obstacles to overcome when using titanium for a bearing race- 1) titanium is flammable when exposed to the oxygen wetted environment inside the space suit and 2) titanium's poor wear properties are often challenging to overcome in tribology applications. In order to evaluate the ignitability of a titanium space suit bearing, a series of tests were conducted at White Sands Test Facility (WSTF) that introduced the bearings to an extreme test profile, with multiple failures imbedded into the test bearings. The testing showed no signs of ignition in the most extreme test cases; however, substantial wear of the bearing races was observed. In order to design a bearing that can last an entire exploration mission (approx. 3 years), design parameters for maximum contact stress need to be identified. To identify these design parameters, bearing test rigs were developed that allow for the quick evaluation of various bearing ball loads, ball diameters, lubricants, and surface treatments. This test data will allow designers to minimize the titanium bearing mass for a specific material and lubricant combination and design around a cycle life requirement for an exploration mission. This paper reviews the current research and testing that has been performed on titanium bearing races to evaluate the use of such materials in an enriched oxygen environment and to optimize the bearing assembly mass and tribological properties to accommodate for the high bearing cycle life for an exploration mission.

Rhodes, Richard↗
NASA NTRS1982

Shuttle entry GN&C performance during STS-1 and STS-2

Data obtained during the entry segment of the descent phase of the flights are analyzed. The nominal entry profile is defined and a description is given of the guidance, navigation, and control subsystem. Emphasis is placed on the stability and control problems encountered during STS-1 and to the changes made in response to these anomalies. These are: (1) the first roll maneuver was done manually at a reduced roll rate; (2) the nominal elevator position was changed from one degree up to one degree down for Mach numbers greater than 12 to reduce the heat load on the body flap; (3) the pilot was directed to execute small roll maneuvers at dynamic pressures of 4, 8, and 18 psf to help determine the roll moment from the aft yaw jets; (4) the planned test inputs in the transonic region were reduced in magnitude; and (5) the targeted touchdown point was moved 500 feet closer to the runway threshold.

Mcwhorter, L. B.↗
NASA NTRS2010

NASA Tech Briefs, April 2010

Topics covered include: Active and Passive Hybrid Sensor; Quick-Response Thermal Actuator for Use as a Heat Switch; System for Hydrogen Sensing; Method for Detecting Perlite Compaction in Large Cryogenic Tanks; Using Thin-Film Thermometers as Heaters in Thermal Control Applications; Directional Spherical Cherenkov Detector; AlGaN Ultraviolet Detectors for Dual-Band UV Detection; K-Band Traveling-Wave Tube Amplifier; Simplified Load-Following Control for a Fuel Cell System; Modified Phase-meter for a Heterodyne Laser Interferometer; Loosely Coupled GPS-Aided Inertial Navigation System for Range Safety; Sideband-Separating, Millimeter-Wave Heterodyne Receiver; Coaxial Propellant Injectors With Faceplate Annulus Control; Adaptable Diffraction Gratings With Wavefront Transformation; Optimizing a Laser Process for Making Carbon Nanotubes; Thermogravimetric Analysis of Single-Wall Carbon Nanotubes; Robotic Arm Comprising Two Bending Segments; Magnetostrictive Brake; Low-Friction, Low-Profile, High-Moment Two-Axis Joint; Foil Gas Thrust Bearings for High-Speed Turbomachinery; Miniature Multi-Axis Mechanism for Hand Controllers; Digitally Enhanced Heterodyne Interferometry; Focusing Light Beams To Improve Atomic-Vapor Optical Buffers; Landmark Detection in Orbital Images Using Salience Histograms; Efficient Bit-to-Symbol Likelihood Mappings; Capacity Maximizing Constellations; Natural-Language Parser for PBEM; Policy Process Editor for P(sup 3)BM Software; A Quality System Database; Trajectory Optimization: OTIS 4; and Computer Software Configuration Item-Specific Flight Software Image Transfer Script Generator.

Source record↗
NASA NTRS1989

The MANTA: An RPV design to investigate forces and moments on a lifting surface

The overall goal was to investigate and exploit the advantages of using remotely powered vehicles (RPV's) for in-flight data collection at low Reynold's numbers. The data to be collected is on actual flight loads for any type of rectangular or tapered airfoil section, including vertical and horizontal stabilizers. The data will be on a test specimen using a force-balance system which is located forward of the aircraft to insure an undisturbed air flow over the test section. The collected data of the lift, drag and moment of the test specimen is to be radioed to a grand receiver, thus providing real-time data acquisition. The design of the mission profile and the selection of the instrumentation to satisfy aerodynamic requirements are studied and tested. A half-size demonstrator was constructed and flown to test the flight worthiness of the system.

Bryan, Kevin↗
DOE OSTI2022

Alkaline Oxidation of Lignin Using Reversibly-Soluble Bases

Production of oxidized aromatic monomers from lignin has been an intriguing process for decades, but widespread implementation has been inhibited by the high hydroxide:lignin ratios required for significant aldehyde yields. The high hydroxide loading in most scenarios renders the process uneconomical even for high-value products such as vanillin. In this work, we explore alkaline oxidation of a lignin-rich enzymatic hydrolysis residue isolated from corn stover, using alkaline earth metal hydroxides, such as Sr(OH)2 and Ba(OH)2 as base promoters. These materials are soluble at reaction temperature, but mostly insoluble at room temperature, allowing recovery and reuse by simple filtration. We show that monomer yields and profiles using these bases is similar to that obtained using NaOH as base, and that Sr(OH)2 can be recovered in yields above 90%. Preliminary TEA and LCA suggest that replacing NaOH with Sr(OH)2 can decrease monomer production costs by 40% and decrease global warming potential in lignin depolymerization by 30%, enabling a more economical and sustainable process.

BIOMASS FUELS↗
DOE OSTI2022

Alkaline Oxidation of Lignin Using Reversibly-Soluble Bases

Production of oxidized aromatic monomers from lignin has been an intriguing process for decades, but widespread implementation has been inhibited by the high hydroxide:lignin ratios required for significant aldehyde yields. The high hydroxide loading in most scenarios renders the process uneconomical even for high-value products such as vanillin. In this work, we explore alkaline oxidation of a lignin-rich enzymatic hydrolysis residue isolated from corn stover, using alkaline earth metal hydroxides, such as Sr(OH)2 and Ba(OH)2 as base promoters. These materials are soluble at reaction temperature, but mostly insoluble at room temperature, allowing recovery and reuse by simple filtration. We show that monomer yields and profiles using these bases is similar to that obtained using NaOH as base, and that Sr(OH)2 can be recovered in yields above 90%. Preliminary TEA and LCA suggest that replacing NaOH with Sr(OH)2 can decrease monomer production costs by 40% and decrease global warming potential in lignin depolymerization by 30%, enabling a more economical and sustainable process.

alkaline oxidation↗
DOE OSTI2021

Uncontrolled Electric Vehicle Charging Impacts on Distribution Electric Power Systems with Primarily Residential, Commercial or Industrial Loads

An increase in Electric Vehicles (EV) will result in higher demands on the distribution electric power systems (EPS) which may result in thermal line overloading and low voltage violations. To understand the impact, this work simulates two EV charging scenarios (home- and work-dominant) under potential 2030 EV adoption levels on 10 actual distribution feeders that support residential, commercial, and industrial loads. The simulations include actual driving patterns of existing (non-EV) vehicles taken from global positioning system (GPS) data. The GPS driving behaviors, which explain the spatial and temporal EV charging demands, provide information on each vehicles travel distance, dwell locations, and dwell durations. Then, the EPS simulations incorporate the EV charging demands to calculate the power flow across the feeder. Simulation results show that voltage impacts are modest (less than 0.01 p.u.), likely due to robust feeder designs and the models only represent the high-voltage (“primary”) system components. Line loading impacts are more noticeable, with a maximum increase of about 15%. Additionally, the feeder peak load times experience a slight shift for residential and mixed feeders (≈1 h), not at all for the industrial, and 8 h for the commercial feeder.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2021

COMPASO : A new halo finder for competitive assignment to spherical overdensities

We describe a new method (compaso) for identifying groups of particles in cosmological N-body simulations. compaso builds upon existing spherical overdensity (SO) algorithms by taking into consideration the tidal radius around a smaller halo before competitively assigning halo membership to the particles. In this way, the compaso finder allows for more effective deblending of haloes in close proximity as well as the formation of new haloes on the outskirts of larger ones. This halo-finding algorithm is used in the abacussummit suite of N-body simulations, designed to meet the cosmological simulation requirements of the Dark Energy Spectroscopic Instrument (DESI) survey. compaso is developed as a highly efficient on-the-fly group finder, which is crucial for enabling good load-balancing between the GPU and CPU and the creation of high-resolution merger trees. In this paper, we describe the halo-finding procedure and its particular implementation in abacus, accompanying it with a qualitative analysis of the finder. We test the robustness of the compaso catalogues before and after applying the cleaning method described in an accompanying paper and demonstrate its effectiveness by comparing it with other validation techniques. We then visualize the haloes and their density profiles, finding that they are well fit by the NFW formalism. Finally, we compare other properties such as radius–mass relationships and two-point correlation functions with that of another widely used halo finder, rockstar.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS1974

Highly loaded multi-stage fan drive turbine - performance of initial seven configurations

Experimental results of a three-stage highly loaded fan drive turbine test program are presented. A plain blade turbine, a tandem blade turbine, and a tangentially leaned stator turbine were designed for the same velocity diagram and flowpath. Seven combinations of bladerows were tested to evaluate stage performances and effects of the tandem blading and leaned stator. The plain blade turbine design point total-to-total efficiency was 0.886. The turbine with the stage three leaned stator had the same efficiency with an improved exit swirl profile and increased hub reaction. Two-stage group tests showed that the two-stage turbine with tandem stage two stator had an efficiency of 0.880 compared to 0.868 for the plain blade two-stage turbine.

Wolfmeyer, G. W.↗
NASA NTRS1983

Friction and hardness of gold films deposited by ion plating and evaporation

Sliding friction experiments were conducted with ion-plated and vapor-deposited gold films on various substrates in contact with a 0.025-mm-radius spherical silicon carbide rider in mineral oil. Hardness measurements were also made to examine the hardness depth profile of the coated gold on the substrate. The results indicate that the hardness is influenced by the depth of the gold coating from the surface. The hardness increases with an increase in the depth. The hardness is also related to the composition gradient in the graded interface between the gold coating and the substrate. The graded interface exhibited the highest hardness resulting from an alloy hardening effect. The coefficient of friction is inversely related to the hardness, namely, the load carrying capacity of the surface. The greater the hardness that the metal surface possesses, the lower is the coefficient of friction. The graded interface exhibited the lowest coefficient of friction.

Miyoshi, K.↗
NASA NTRS2000

Airfoil Dynamic Stall and Rotorcraft Maneuverability

The loading of an airfoil during dynamic stall is examined in terms of the augmented lift and the associated penalties in pitching moment and drag. It is shown that once stall occurs and a leading-edge vortex is shed from the airfoil there is a unique relationship between the augmented lift, the negative pitching moment, and the increase in drag. This relationship, referred to here as the dynamic stall function, shows limited sensitivity to effects such as the airfoil section profile and Mach number, and appears to be independent of such parameters as Reynolds number, reduced frequency, and blade sweep. For single-element airfoils there is little that can be done to improve rotorcraft maneuverability except to provide good static C(l(max)) characteristics and the chord or blade number that is required to provide the necessary rotor thrust. However, multi-element airfoils or airfoils with variable geometry features can provide augmented lift in some cases that exceeds that available from a single-element airfoil. The dynamic stall function is shown to be a useful tool for the evaluation of both measured and calculated dynamic stall characteristics of single element, multi-element, and variable geometry airfoils.

Bousman, William G.↗
NASA NTRS2008

A Modified LC/MS/MS Method with Enhanced Sensitivity for the Determination of Scopolamine in Human Plasma

Intranasal scopolamine is a choice drug for the treatment of motion sickness during space flight because of its quick onset of action, short half-life and favorable sideeffects profile. The dose administered usually ranges between 0.1 and 0.4 mg. Such small doses make it difficult to detect concentrations of scopolamine in biological fluids using existing sensitive LC/MS/MS method, especially when the biological sample volumes are limited. To measure scopolamine in human plasma to facilitate pharmacokinetic evaluation of the drug, we developed a sensitive LC/MS/MS method using 96 well micro elution plates for solid phase extraction (SPE) of scopolamine in human plasma. Human plasma (100-250 micro L) were loaded onto Waters Oasis HLB 96 well micro elution plate and eluted with 50 L of organic solvent without evaporation and reconstitution. HPLC separation of the eluted sample was performed using an Agilent Zorbax SB-CN column (50 x 2.1 mm) at a flow rate of 0.2 mL/min for 3 minutes. The mobile phase for separation was 80:20 (v/v) methanol: ammonium acetate (30 mM) in water. Concentrations of scopolamine were determined using a Micromass Quattro Micro(TM) mass spectrometer with electrospray ionization (ESI). ESI mass spectra were acquired in positive ion mode with multiple reaction monitoring for the determination of scopolamine m/z = 304.2 right arrow 138.1 and internal standard hyoscyamine m/z = 290.2 right arrow 124.1. The method is rapid, reproducible, specific and has the following parameters: scopolamine and the IS are eluted at about 1.1 and 1.7 min respectively. The linear range is 25-10000 pg/mL for scopolamine in human plasma with correlation coefficients greater than 0.99 and CV less than 0.5%. The intra-day and inter-day CVs are less than 15% for quality control samples with concentrations of 75,300, and 750 pg/mL of scopolamine in human plasma. SPE using 96 well micro elution plates allows rapid sample preparation and enhanced sensitivity for the LC/MS/MS determination of scopolamine in a small volume of biological samples. The new method is also cost effective since it uses a small volume of organic solvents compared to the methods using SPE cartridges or regular 96 well SPE plates. This method can be successfully used for bioavailability and pharmacokinetic evaluations of scopolamine, especially when volumes of biological samples are limited. Further investigation to use automated SPE system with 96 well micro elution plates is planned.

Wang, Zuwei↗