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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 91 records · Page 5
All sourcesNASA NTRSDOE OSTI
DOE OSTI2025

X-ray thermal diffuse scattering as a texture-robust temperature diagnostic for dynamically compressed solids

We present a model of x-ray thermal diffuse scattering (TDS) from a cubic polycrystal with an arbitrary crystallographic texture, based on the classic approach of Warren [B. E. Warren, Acta Crystallogr. 6, 803 (1953)]. We compare the predictions of our model with femtosecond x-ray diffraction patterns gathered from ambient and dynamically compressed rolled copper foils obtained at the High Energy Density instrument of the European X-Ray Free-Electron Laser facility and find that the texture-aware TDS model yields more accurate results than does the conventional powder model owed to Warren. Nevertheless, we further show: with sufficient angular detector coverage, the TDS signal is largely unchanged by sample orientation and in all cases strongly resembles the signal from a perfectly random powder; shot-to-shot fluctuations in the TDS signal resulting from grain-sampling statistics are at the percent level, in stark contrast to the fluctuations in the Bragg-peak intensities (which are over an order of magnitude greater); and TDS is largely unchanged even following texture evolution caused by compression-induced plastic deformation. We conclude that TDS is robust against texture variation, making it a flexible temperature diagnostic applicable just as well to off-the-shelf commercial foils as to ideal powders.

Crystal lattices↗
NASA NTRS2004

Development of Advanced Low Conductivity Thermal Barrier Coatings

Advanced multi-component, low conductivity oxide thermal barrier coatings have been developed using an approach that emphasizes real-time monitoring of thermal conductivity under conditions that are engine-like in terms of temperatures and heat fluxes. This is in contrast to the traditional approach where coatings are initially optimized in terms of furnace and burner rig durability with subsequent measurement in the as-processed or furnace-sintered condition. The present work establishes a laser high-heat-flux test as the basis for evaluating advanced plasma-sprayed and electron beam-physical vapor deposited (EB-PVD) thermal barrier coatings under the NASA Ultra-Efficient Engine Technology (UEET) Program. The candidate coating materials for this program are novel thermal barrier coatings that are found to have significantly reduced thermal conductivities and improved thermal stability due to an oxide-defect-cluster design. Critical issues for designing advanced low conductivity coatings with improved coating durability are also discussed.

Zhu, Dong-Ming↗
DOE OSTI2021

Directed energy deposition additive manufacturing of functionally graded Al-W composites

Directed energy deposition using laser heat sources (DED-L) is a metal additive manufacturing method that can be used to fabricate functionally graded materials by feeding multiple powder streams directly into a laser-generated melt pool. Additionally, the composition can be spatially varied by independent control of the materials feed rates. DED-L additive manufacturing is used in this work to create continuously graded Al/W composites that span 0–55 vol% W in Al over length scales from 0.6 to 1.2 mm with individual layers on the order of 0.1 mm and powder particle sizes on the order of 10 µm. The obtained composition and thickness ranges are comparable to those typically achieved using conventional powder metallurgy approaches and enables fabrication of composites to be used as a high impedance graded density impactor (GDI) in dynamic ramp compression experiments to study matter under extreme conditions. DED-L additive manufacturing of a GDI presents an opportunity to reduce GDI fabrication time to less than a day compared to many weeks by conventional methods. It is also possible to scale the deposition by DED-L to essentially unlimited dimensions in the lateral directions, whereas conventional methods become limited.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Selective CW Laser Synthesis of MoS2 and Mixture of MoS2 and MoO2 from (NH4)2MoS4 Film

Very recently, the synthesis of 2D MoS2 and WS2 through pulsed laser-directed thermolysis can achieve wafer-scale and large-area structures, in ambient conditions. In this paper, we report the synthesis of MoS2 and MoS2 oxides from (NH4)2MoS4 film using a visible continuous-wave (CW) laser at 532 nm, instead of the infrared pulsed laser for the laser-directed thermolysis. The (NH4)2MoS4 film is prepared by dissolving its crystal powder in DI water, sonicating the solution, and dip-coating onto a glass slide. We observed a laser intensity threshold for the laser synthesis of MoS2, however, it occurred in a narrow laser intensity range. Above that range, a mixture of MoS2 and MoO2 is formed, which can be used for a memristor device, as demonstrated by other research groups. We did not observe a mixture of MoS2 and MoO3 in the laser thermolysis of (NH4)2MoS4. The laser synthesis of MoS2 in a line pattern is also achieved through laser scanning. Due to of the ease of CW beam steering and the fine control of laser intensities, this study can lead toward the CW laser-directed thermolysis of (NH4)2MoS4 film for the fast, non-vacuum, patternable, and wafer-scale synthesis of 2D MoS2.

(NH4)2MoS4↗
DOE OSTI2020

Parallel Broadband Femtosecond Reflection Spectroscopy at a Soft X-Ray Free-Electron Laser

X-ray absorption spectroscopy (XAS) and the directly linked X-ray reflectivity near absorption edges yield a wealth of specific information on the electronic structure around the resonantly addressed element. Observing the dynamic response of complex materials to optical excitations in pump–probe experiments requires high sensitivity to small changes in the spectra which in turn necessitates the brilliance of free electron laser (FEL) pulses. However, due to the fluctuating spectral content of pulses generated by self-amplified spontaneous emission (SASE), FEL experiments often struggle to reach the full sensitivity and time-resolution that FELs can in principle enable. Here, we implement a setup which solves two common challenges in this type of spectroscopy using FELs: First, we achieve a high spectral resolution by using a spectrometer downstream of the sample instead of a monochromator upstream of the sample. Thus, the full FEL bandwidth contributes to the measurement at the same time, and the FEL pulse duration is not elongated by a monochromator. Second, the FEL beam is divided into identical copies by a transmission grating beam splitter so that two spectra from separate spots on the sample (or from the sample and known reference) can be recorded in-parallel with the same spectrometer, enabling a spectrally resolved intensity normalization of pulse fluctuations in pump–probe scenarios. We analyze the capabilities of this setup around the oxygen K- and nickel L-edges recorded with third harmonic radiation of the free electron laser in Hamburg (FLASH), demonstrating the capability for pump–probe measurements with sensitivity to reflectivity changes on the per mill level.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Direct Laser Impulse (DLI) System Alignment: Requirements Engineering Project

The National Ignition Facility (NIF) is the world’s largest and most energetic laser, and it is comprised of 192 laser beams that must align onto one target for the purpose of learning about Internal Confinement Fusion (ICF) and High Energy Density (HED) physics. A new NIF capability under development is the Direct Laser Impulse (DLI). The DLI capability will provide a test environment where high pulsed laser energy is delivered to a three-dimensional target. Achieving this delivery to target relies on a precision alignment and positioning of the two redirected NIF beams, as shown in Figure 1. When aligned, the two combined beams—with a frequency converted from infrared (IR) to green laser light, at a fluence (energy per unit area) of roughly 20 joules per square centimeter—will be capable of delivering up to 30 kilojoules of direct, unfocused energy to a one cubic foot target. The 40-cm x 40-cm aligned impulse area at the DLI target interaction plane (TIP) is achieved by using a beam path comprised of pickoff and transport mirrors, frequency conversion crystals, optics serving as environmental barriers, and debris shields. A separate aligned diagnostic beam path is also required for impulse to TIP characterization. Final in-situ alignment is required for the two populated diverted NIF beam paths onto the DLI target as well as the diagnostic optical beam path. Existing NIF alignment subsystems do not offer references that meet DLI’s unique demand. The new DLI Red Box, which has been designed to allow for alignment, has been shown to require deviation from the intended configuration and operational use case to obtain adequate functionality. A systems engineering evaluation has identified a solution that meets the stakeholder requirements while optimizing key performance parameters. The solution, referred to in this document as the Red Box “+” Rotated, was determined to be an improved version of the current DLI Red Box. This system offers improved system repeatability and alignment stability while maintaining similar interfaces and decreasing the demand for engineer/operator interaction.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2024

Broadband Frequency Conversion of Spectrally Incoherent Pulses and Initial Laser-Plasma Instabilities Mitigation Experiments

There is a need for efficient broadband frequency conversion schemes from the infrared, where optical pulses are efficiently amplified by solid-state laser materials, to the ultraviolet, a wavelength range more suitable for inertial confinement fusion (ICF). The current schemes are inadequate for broadband, spectrally incoherent optical pulses composed of a large number of frequency components distributed over a large frequency range. Implementing novel technologies that generate optical pulses with a large number of spectral components improves the laser-target interaction. In particular, it has long been believed that broad bandwidth mitigates the electron-plasma-wave instabilities that generate suprathermal electrons, which degrade ICF performance by increasing the fuel adiabat and reducing the shell areal density. It is important to develop a platform to demonstrate hot electron suppression caused by the larger available bandwidth, which has not previously been feasible in the laboratory. Experimentally measuring and theoretically assessing these effects with adequately benchmarked simulation codes are paramount to the design and development of novel laser facilities aiming at producing energy via laser fusion. The Laboratory for Laser Energetics is building a new laser facility, the Fourth-generation Laser for Ultrabroadband eXperiments (FLUX), to generate high-energy nanosecond laser pulses with fractional bandwidth larger than 1% in the ultraviolet and perform combined experiments with the 60-beam Omega facility. This large increase in bandwidth from the ~ 0.1% currently available on high-energy laser systems, is achieved by combining amplification in nonlinear optical parametric amplifiers (OPAs) around 1053 nm (1w) with nonlinear frequency conversion to the ultraviolet (around 351 nm, 3w). The novel scheme for frequency conversion is based on the noncollinear sum-frequency generation (SFG) of the angularly dispersed amplified 1w output with a narrowband 2w pulse, which is also used to pump the OPA system. The proposal funded scientific and engineering studies necessary to implement this novel laser facility, accelerated the SFG deployment by funding additional project team resources (shop time, engineers, and technicians), and funded preliminary experiments on the Omega Laser.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
NASA NTRS2005

NASA Tech Briefs, February 2005

Topics discussed include: Instrumentation for Sensitive Gas Measurements; Apparatus for Testing Flat Specimens of Thermal Insulation; Quadrupole Ion Mass Spectrometer for Masses of 2 to 50 Da; Miniature Laser Doppler Velocimeter for Measuring Wall Shear; Coherent Laser Instrument Would Measure Range and Velocity; Printed Microinductors for Flexible Substrates; Digital Receiver for Microwave Radiometry; Printed Antennas Made Reconfigurable by Use of MEMS Switches; Traffic-Light-Preemption Vehicle-Transponder Software Module; Intersection-Controller Software Module; Central-Monitor Software Module; Estimating Effects of Multipath Propagation on GPS Signals; Parallel Adaptive Mesh Refinement Library; Predicting Noise From Aircraft Turbine-Engine Combustors; Generating Animated Displays of Spacecraft Orbits; Diagnosis and Prognosis of Weapon Systems; Training Software in Artificial-Intelligence Computing Techniques; APGEN Version 5.0; Single-Command Approach and Instrument Placement by a Robot on a Target; Three-Dimensional Audio Client Library; Isogrid Membranes for Precise, Singly Curved Reflectors; Nickel-Tin Electrode Materials for Nonaqueous Li-Ion Cells; Photocatalytic Coats in Glass Drinking-Water Bottles; Fast Laser Shutters With Low Vibratory Disturbances; Series-Connected Buck Boost Regulators; Space Physics Data Facility Web Services; Split-Resonator, Integrated-Post Vibratory Microgyroscope; Blended Buffet-Load-Alleviation System for Fighter Airplane; Gifford-McMahon/Joule-Thomson Refrigerator Cools to 2.5 K; High-Temperature, High-Load-Capacity Radial Magnetic Bearing; Fabrication of Spherical Reflectors in Outer Space; Automated Rapid Prototyping of 3D Ceramic Parts; Tissue Engineering Using Transfected Growth-Factor Genes; Automation of Vapor-Diffusion Growth of Protein Crystals; Atom Skimmers and Atom Lasers Utilizing Them; Gears Based on Carbon Nanotubes; Patched Off-Axis Bending/Twisting Actuators for Thin Mirrors; and Improving Control in a Joule-Thomson Refrigerator.

Source record↗
NASA NTRS2014

Terrain Physical Properties Derived from Orbital Data and the First 360 Sols of Mars Science Laboratory Curiosity Rover Observations in Gale Crater

Physical properties of terrains encountered by the Curiosity rover during the rst 360 sols of operations have been inferred from analysis of the scour zones produced by Sky Crane Landing System engine plumes, wheel touch down dynamics, pits produced by Chemical Camera (ChemCam) laser shots, rover wheel traverses over rocks, the extent of sinkage into soils, and the magnitude and sign of rover-based slippage during drives. Results have been integrated with morphologic, mineralogic, and thermophysical properties derived from orbital data, and Curiosity-based measurements, to understand the nature and origin of physical properties of traversed terrains. The hummocky plains (HP) landing site and traverse locations consist ofmoderately to well-consolidated bedrock of alluvial origin variably covered by slightly cohesive, hard-packedbasaltic sand and dust, with both embedded and surface-strewn rock clasts. Rock clasts have been addedthrough local bedrock weathering and impact ejecta emplacement and form a pavement-like surface in whichonly small clasts (5 to 10 cm wide) have been pressed into the soil during wheel passages. The beddedfractured (BF) unit, site of Curiositys rst drilling activity, exposes several alluvial-lacustrine bedrock unitswith little to no soil cover and varying degrees of lithication. Small wheel sinkage values (1 cm) for both HPand BF surfaces demonstrate that compaction resistance countering driven-wheel thrust has been minimaland that rover slippage while traversing across horizontal surfaces or going uphill, and skid going downhill,have been dominated by terrain tilts and wheel-surface material shear modulus values.

Mars Science Laboratory Curiosity Gale Crater↗
NASA NTRS2000

Lidar Technology at the Goddard Laser and Electro-Optics Branch

The Laser and Electro-Optics Branch at Goddard Space flight Center was established about three years ago to provide a focused center of engineering support and technology development in these disciplines with an emphasis on spaced based instruments for Earth and Space Science. The Branch has approximately 15 engineers and technicians with backgrounds in physics, optics, and electrical engineering. Members of the Branch are currently supporting a number of space based lidar efforts as well as several technology efforts aimed at enabling future missions. The largest effort within the Branch is support of the Ice, Cloud, and land Elevation Satellite (ICESAT) carrying the Geoscience Laser Altimeter System (GLAS) instrument. The ICESAT/GLAS primary science objectives are: 1) To determine the mass balance of the polar ice sheets and their contributions to global sea level change; and 2) To obtain essential data for prediction of future changes in ice volume and sea-level. The secondary science objectives are: 1) To measure cloud heights and the vertical structure of clouds and aerosols in the atmosphere; 2) To map the topography of land surfaces; and 3) To measure roughness, reflectivity, vegetation heights, snow-cover, and sea-ice surface characteristics. Our efforts have concentrated on the GLAS receiver component development, the Laser Reference Sensor for the Stellar Reference System, the GLAS fiber optics subsystems, and the prelaunch calibration facilities. We will report on our efforts in the development of the space qualified interference filter [Allan], etalon filter, photon counting detectors, etalor/laser tracking system, and instrument fiber optics, as well as specification and selection of the star tracker and development of the calibration test bed. We are also engaged in development work on lidar sounders for chemical species. We are developing new lidar technology to enable a new class of miniature lidar instruments that are compatible with small Discovery-class orbiters now in the NASA planetary program. The purpose of the lidar is to continuously profile the water vapor and dust in the Mars atmosphere from orbit in order to quantify its dynamics, their relationship in the diurnal cycles, and to infer water vapor exchange with the Mars surface. To remotely measure the water-vapor height profiles, we will use the differential absorption lidar (DIAL) technique. We are also developing a laser sensor for measuring the total column content of CO2 in the atmosphere of the earth. CO2 is the principal greenhouse gas and has increased by roughly 80 ppm in the last century and a half. We will report our efforts in the development of the laser transmitter and photon counting detector components for a Mars Orbiting DIAL system and for the CO2 sounder.

Heaps, William S.↗
NASA NTRS2001

Flame-Vortex Interactions Imaged in Microgravity - To Assess the Theory Flame Stretch

The goals of this research are to: 1) Assess the Theory of Flame Stretch by operating a unique flame-vortex experiment under microgravity conditions in the NASA Glenn 2.2 Second Drop Tower (drops to identify operating conditions have been completed); 2) Obtain high speed shadowgraph images (500-1000 frames/s) using the drop rig (images were obtained at one-g, and the NASA Kodak RO camera is being mounted on the drop rig); 3) Obtain shadowgraph and PIV images at 1-g while varying the effects of buoyancy by controlling the Froude number (completed); 4) Numerically model the inwardly-propagating spherical flame that is observed in the experiment using full chemistry and the RUN 1DL code (completed); 5) Send images of the flame shape to Dr. G. Patniak at NRL who is numerically simulating the entire flame-vortex interaction of the present experiment (data transfer completed); and 6) Assess the feasibility of obtaining PIV velocity field images in the drop rig, which would be useful (but not required) for our assessment of the Theory of Flame Stretch (PIV images were obtained at one-g using same low laser power that is available from fiber optic cable in drop tower). The motivation for the work is to obtain novel measurement needed to develop a physically accurate model of turbulent combustion that can help in the control of engine pollutants. The unique experiment allows, for the first time, the detailed study of a negatively-curved (negatively stretched) flame, which is one of the five fundamental types of premixed flames. While there have been studies of flat flames, positively-curved (outwardly-propagating) cases and positively-strained (counterflow) cases, this is the first detailed study of a negatively-curved (inwardly-propagating) flame. The first set of drops in the 2.2 Second Drop Tower showed that microgravity provides more favorable conditions for achieving inwardly-propagating flames (IPFs) than 1-g. A vortex interacts with a flame and creates a spherical pocket, which burns inwardly. Shadowgraphs at 1000 frames/sec quantify the Markstein number and flame speed. A Low-Laser Power PIV System was developed and is being added to the drop package. Numerical computations were required to explain why the Markstein numbers measured for the inwardly-propagating flames differ from those of outward propagating flames; this is an important research issue in the assessment of the Theory of Flame Stretch. The RUN-1DL code (developed by Prof. B. Rogg) was run for IPF and OPFs with complex methane and propane chemistry. Results confirmed that Ma for the IPFs are larger than for OPFs as was observed experimentally. Physical reasons for these new findings about the Theory of Flame Stretch are being determined from the experiments and the computations. Several journal papers have been published; the drop package is described in the AIAA Journal, while the one-g results appear in three other journal papers.

Driscoll, James F.↗
DOE OSTI2021

Fuel properties effects on wall-wetting and fuel-in-lube dilution under stochastic pre ignition prone conditions

Fuel-engine interactions have been shown to influence stochastic pre-ignition (SPI), however there is uncertainty on the root causes, participially if effects are primarily physical or chemical in nature. To better delineate the physical and chemical dependencies of fuel properties on SPI, this work studies interactions between aromatics, distillation, and particle matter index on SPI with a laser induced fluorescence (LIF) diagnostic to observe wall wetting. Fuels with high aromatic components or higher distillation temperatures tend to increase SPI events, but it is not well understood if the increased fuel dilution or a chemical aspect of this process is the primary mechanism for SPI. By employing the novel LIF in this work we measure fuel dilution in real-time in a running single cylinder research engine operated at SPI conditions. Three fuels were used in the present work, with the LIF diagnostic. Each fuel was operated at two injection timings, generating fuel specific effects on wall wetting. The LIF measurements are coupled with engine combustion measurements and SPI event counts. Results enable a deconvolution of fuel physical and chemical properties on SPI propensity, providing unique and novel insights into the dominant fuel effects affecting SPI.

Splitter, Derek↗
DOE OSTI2026

Control of Nonlinear Compton Scattering in a Squeezed Vacuum

Electromagnetic radiation by accelerated charges is a fundamental process in physics. Here, we introduce a quantum-optical framework for controlling the emission of radiation of an electron in an intense laser field via squeezed vacuum states. By engineering the quantum fluctuations of the emission modes, we demonstrate that the probability of nonlinear Compton scattering can be significantly enhanced or suppressed through tunable squeezing amplitude and angle. We show numerically that our predictions are experimentally accessible with current squeezing technologies, establishing a new paradigm for quantum control in high-intensity light-matter interactions.

Light-matter interaction↗
DOE OSTI2023

Cadmium Magnesium Telluride for Next-Generation X-Ray Free Electron Laser, Synchrotron, and Many Other Applications

We developed a picosecond photodetector based on our Bridgman-grown and specially engineered cadmium magnesium telluride (Cd 1–x MgxTe) single crystal that is sensitive to both optical and X-ray pulses for coarse timing in free-electron laser applications. Cd 1–x MgxTe is a widebandgap semiconductor with potential applications, not only in optoelectronics, but also in particle physics as an intense pulse radiation detector for bremsstrahlung, X-ray/gamma-ray radiation, thermal neutrons, and medical imaging. For femtosecond optical and X-ray crosscorrelation, the material must have a very short lifetime, a condition that is opposite to that required for nuclear spectroscopy applications. At the same time, the material also needs to have a very low bulk leakage current, in the 10–90 nA range for voltages to even 1000 V. Hence, the ability to tailor or engineer the material is very crucial. Picosecond response and the crystal growth of this specially engineered Cd 1–x MgxTe material are presented. Furthermore, other characterization and transient measurements are discussed along with room-temperature semiconductor detector performance for other nuclear radiation detection applications.

36 MATERIALS SCIENCE↗