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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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All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

A Closer Look at a Stronger Titanium

An improved titanium alloy – stronger than any commercial titanium alloy currently on the market – gets its strength from the novel way atoms are arranged to form a special nanostructure. For the first time, researchers at Pacific Northwest National Laboratory have been able to see this alignment and then manipulate it to make it even stronger. Using powerful electron microscopes and a unique atom probe imaging approach at EMSL, the Environmental Molecular Sciences Laboratory, a DOE Office of Science User Facility located at PNNL, they were able to peer deep inside the alloy’s nanostructure to see what was happening.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Alignments in the orientation of radio jets from AGN and their host galaxies

It is well established that active galactic nuclei (AGNs) play an important role in the evolution of galaxies. These AGNs can be linked to the accretion processes onto massive black holes and past merger events in their host galaxies, which may lead to different alignments of the jets with respect to the host galaxies. This paper presents a study of the position angle (PA) differences between radio and optical images of radio-AGNs based on the second data release (DR2) of the Low Frequency Array (LOFAR) Two-Meter Sky Survey (LoTSS), theKarl G. JanskyVery Large Array Faint Images of the Radio Sky at Twenty-Centimeters Survey (FIRST), the Dark Energy Spectroscopic Instrument (DESI) Legacy Imaging Surveys, and the Sloan Digital Sky Survey (SDSS). We assessed PA measurement biases in the data and classified the radio-AGNs based on the radio luminosity and infrared colour from the Wide-field Infrared Survey Explorer (WISE). This resulted in the largest sample of radio AGNs with reliable radio and optical PA measurements published to date, with a total of 3682 AGNs. The PA difference (dPA) distributions for the radio-AGN sample show a prominent minor-axis alignment tendency. Based on some simple assumptions, we simulated the projection effect to estimate the intrinsic jet-galaxy alignment. The observed dPA distribution can be well described by a two-component jet-alignment model in which one component is more aligned with the minor axis of the host galaxy than the other. The fitting results indicate that the jet alignment is dependent on radio luminosity and the shape of the host galaxies, with the jets being more likely to be aligned with the minor axis of the galaxy for lower radio luminosity and for optically more elongated radio-AGNs. The minor-axis alignment of the entire sample may suggest a coherent accretion model present in most AGN host galaxies, while a considerable number of luminous radio-AGNs with massive host galaxies might have undergone accretion – according to the chaotic model – or past merger events.

Astronomy & Astrophysics↗
NASA NTRS1994

Interplanetary magnetic field dependency of stable Sun-aligned polar cap arcs

This is the first analysis, using a statistically significant data set, of the morphological dependence of the presence, orientation, and motion of stable sun-aligned polar cap arcs upon the vector interplanetary magnetic field (IMF). For the one winter season analyzed we had 1392 all-sky 630.0-nm images of 2-min resolution containing a total of 150 polar cap arcs, all with corresponding values of the IMF as measured by International Monitoring Platform (IMP) 8 or International Sun Earth Explorer (ISEE) 2. After demonstrating an unbiased data set with smooth normal distributions of events versus the dimensions of time, space, and IMF component, we examine IMF dependencies of the properties of the optical arcs. A well-defined dependence for B(sub z) is found for the presence/absence of stable Sun-aligned polar cap arcs. Consistent with previous statistical studies, the probability of observing polar cap aurora steadily increases for larger positive values of B(sub z), and linearly decreases when B(sub z) becomes more negative. The probability of observing Sun-aligned arcs within the polar cap is determined to vary sharply as a function of the arc location; arcs were observed 40% of the time on the dawnside and only 10% on the duskside. This implies an overall probability of at least 40% for the whole polar cap. 20% of the arcs were observed during 'southward IMF conditions,' but in fact under closer inspection were found to have been formed under northward IMF conditions; these 'residual' positive B(sub z) arcs ha d a delayed residence time in the polar cap of about what would be expected after a north to south transition of B(sub z). A firm dependence on B(sub y) is also found for both the orientation and the dawn-dusk direction of motion of the arcs. All the arcs are Sun-aligned to a first approximation, but present deviations from this orientation, depending primarily upon the location of the arc in corrected geomagnetic (CG) coordinates. The arcs populating the 06-12 and the 12-18 quadrants of the CG coordinate system point toward the cusp. The B(sub y) dependency of the arc alignment is consistent with a cusp displacement in local time according to the sign of B(sub y). We found that the arc direction of motion depended both on B(sub y) and the arc location within the polar cap. For a given value of B(sub y) two well-defined regions (or cells) exist. Within each cell the arcs move in the same direction toward the boundary between the cells. The arcs located in the duskside move dawnward; those in the dawnside move duskward. The relative size of these dusk and dawn regions (or cells) are controlled by the magnitude of B(sub y). This persistent dusk-dawn motion fo the polar cap arcs is interpreted in terms of newly open flux tubes entering the polar cap and exerting a displacement of the convective cells and the polar cap arcs that are embedded within them.

Valladares, C. E.↗
DOE OSTI2019

Angular alignment and fidelity of neutron phase-gratings for improved interferometer fringe visibility

The recent development of phase-grating moiré neutron interferometry promises a wide range of impactful experiments from dark-field imaging of material microstructure to precise measurements of fundamental constants. However, the contrast of 3% obtained using this moiré interferometer was well below the theoretical prediction of 30% using ideal gratings. It is suspected that non-ideal aspects of the phase-gratings was a leading contributor to this deficiency and that phase-gratings needed to be quantitatively assessed and optimized. Here we characterize neutron diffraction from phase-gratings using Bragg diffraction crystals to determine the optimal phase-grating orientations. We show well-defined diffraction peaks and explore perturbations to the diffraction peaks and the effects on interferometer contrast as a function of grating alignment. This technique promises to improve the contrast of the grating interferometers by providing in-situ aides to grating alignment.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

A study on different morphological structures of zinc oxide nanostructures for humidity sensing application

Effects of different morphological structures of ZnO to the performance of the device in the humidity sensing have been studied. Two different kinds of nanostructures were obtained which are nanords and nanoflakes. From the surface morphology image, the ZnO nanoflakes has lower diameter size of 100 nm compared to ZnO nanorods of 250 nm. The ZnO nanoflakes are not aligned and has low porous structure compared to ZnO nanorods. The humidity sensor performance of ZnO nanorods has superior performance compared to ZnO nanoflakes. The sensitivity of the ZnO nanorods sensor is 3.20 which are almost two times higher than the ZnO nanoflakes of 1.65. The structural properties of the samples have been characterized using field emission scanning electron microscopy (FESEM) electrical properties has been characterized using current voltage (I-V) measurement.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2016

eHXI: A permanently installed, hard x-ray imager for the National Ignition Facility

We have designed and built a multi-pinhole imaging system for high energy x-rays (≥ 50 keV) that is permanently installed in the equatorial plane outside of the target chamber at the National Ignition Facility (NIF). It records absolutely-calibrated, time-integrated x-ray images with the same line-of-sight as the multi-channel, spatially integrating hard x-ray detector FFLEX [McDonald et al., Rev. Sci. Instrum. 75 (2004) 3753], having a side view of indirect-drive inertial confinement fusion (ICF) implosion targets. The equatorial hard x-ray imager (eHXI) has recorded images on the majority of ICF implosion experiments since May 2011. Lastly, eHXI provides valuable information on hot electron distribution in hohlraum experiments, target alignment, potential hohlraum drive asymmetries and serves as a long term reference for the FFLEX diagnostics.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2015

SU-E-J-37: Feasibility of Utilizing Carbon Fiducials to Increase Localization Accuracy of Lumpectomy Cavity for Partial Breast Irradiation

Purpose To investigate the feasibility of utilizing carbon fiducials to increase localization accuracy of lumpectomy cavity for partial breast irradiation (PBI). Methods Carbon fiducials were placed intraoperatively in the lumpectomy cavity following resection of breast cancer in 11 patients. The patients were scheduled to receive whole breast irradiation (WBI) with a boost or 3D-conformal PBI. WBI patients were initially setup to skin tattoos using lasers, followed by orthogonal kV on-board-imaging (OBI) matching to bone per clinical practice. Cone beam CT (CBCT) was acquired weekly for offline review. For the boost component of WBI and PBI, patients were setup with lasers, followed by OBI matching to fiducials, with final alignment by CBCT matching to fiducials. Using carbon fiducials as a surrogate for the lumpectomy cavity and CBCT matching to fiducials as the gold standard, setup uncertainties to lasers, OBI bone, OBI fiducials, and CBCT breast were compared. Results Minimal imaging artifacts were introduced by fiducials on the planning CT and CBCT. The fiducials were sufficiently visible on OBI for online localization. The mean magnitude and standard deviation of setup errors were 8.4mm ± 5.3 mm (n=84), 7.3mm ± 3.7mm (n=87), 2.2mm ± 1.6mm (n=40) and 4.8mm ± 2.6mm (n=87), for lasers, OBI bone, OBI fiducials and CBCT breast tissue, respectively. Significant migration occurred in one of 39 implanted fiducials in a patient with a large postoperative seroma. Conclusion OBI carbon fiducial-based setup can improve localization accuracy with minimal imaging artifacts. With increased localization accuracy, setup uncertainties can be reduced from 8mm using OBI bone matching to 3mm using OBI fiducial matching for PBI treatment. This work demonstrates the feasibility of utilizing carbon fiducials to increase localization accuracy to the lumpectomy cavity for PBI. This may be particularly attractive for localization in the setting of proton therapy and other scenarios in which metal clips are contraindicated.

60 APPLIED LIFE SCIENCES↗
NASA NTRS2006

NASA Tech Briefs, April 2006

The topics covered include: 1) Replaceable Sensor System for Bioreactor Monitoring; 2) Unitary Shaft-Angle and Shaft-Speed Sensor Assemblies; 3) Arrays of Nano Tunnel Junctions as Infrared Image Sensors; 4) Catalytic-Metal/PdO(sub x)/SiC Schottky-Diode Gas Sensors; 5) Compact, Precise Inertial Rotation Sensors for Spacecraft; 6) Universal Controller for Spacecraft Mechanisms; 7) The Flostation - an Immersive Cyberspace System; 8) Algorithm for Aligning an Array of Receiving Radio Antennas; 9) Single-Chip T/R Module for 1.2 GHz; 10) Quantum Entanglement Molecular Absorption Spectrum Simulator; 11) FuzzObserver; 12) Internet Distribution of Spacecraft Telemetry Data; 13) Semi-Automated Identification of Rocks in Images; 14) Pattern-Recognition Algorithm for Locking Laser Frequency; 15) Designing Cure Cycles for Matrix/Fiber Composite Parts; 16) Controlling Herds of Cooperative Robots; 17) Modification of a Limbed Robot to Favor Climbing; 18) Vacuum-Assisted, Constant-Force Exercise Device; 19) Production of Tuber-Inducing Factor; 20) Quantum-Dot Laser for Wavelengths of 1.8 to 2.3 micron; 21) Tunable Filter Made From Three Coupled WGM Resonators; and 22) Dynamic Pupil Masking for Phasing Telescope Mirror Segments.

Source record↗
NASA NTRS2000

Horizon: A Proposal for Large Aperture, Active Optics in Geosynchronous Orbit

In 1999, NASA's New Millennium Program called for proposals to validate new technology in high-earth orbit for the Earth Observing-3 (NMP EO3) mission to fly in 2003. In response, we proposed to test a large aperture, active optics telescope in geosynchronous orbit. This would flight-qualify new technologies for both Earth and Space science: 1) a future instrument with LANDSAT image resolution and radiometric quality watching continuously from geosynchronous station, and 2) the Next Generation Space Telescope (NGST) for deep space imaging. Six enabling technologies were to be flight-qualified: 1) a 3-meter, lightweight segmented primary mirror, 2) mirror actuators and mechanisms, 3) a deformable mirror, 4) coarse phasing techniques, 5) phase retrieval for wavefront control during stellar viewing, and 6) phase diversity for wavefront control during Earth viewing. Three enhancing technologies were to be flight- validated: 1) mirror deployment and latching mechanisms, 2) an advanced microcontroller, and 3) GPS at GEO. In particular, two wavefront sensing algorithms, phase retrieval by JPL and phase diversity by ERIM International, were to sense optical system alignment and focus errors, and to correct them using high-precision mirror mechanisms. Active corrections based on Earth scenes are challenging because phase diversity images must be collected from extended, dynamically changing scenes. In addition, an Earth-facing telescope in GEO orbit is subject to a powerful diurnal thermal and radiometric cycle not experienced by deep-space astronomy. The Horizon proposal was a bare-bones design for a lightweight large-aperture, active optical system that is a practical blend of science requirements, emerging technologies, budget constraints, launch vehicle considerations, orbital mechanics, optical hardware, phase-determination algorithms, communication strategy, computational burdens, and first-rate cooperation among earth and space scientists, engineers and managers. This manuscript presents excerpts from the Horizon proposal's sections that describe the Earth science requirements, the structural -thermal-optical design, the wavefront sensing and control, and the on-orbit validation.

Chesters, Dennis↗
NASA NTRS2006

Pointing Reference Scheme for Free-Space Optical Communications Systems

A scheme is proposed for referencing the propagation direction of the transmit laser signal in pointing a free-space optical communications terminal. This recently developed scheme enables the use of low-cost, commercial silicon-based sensors for tracking the direction of the transmit laser, regardless of the transmit wavelength. Compared with previous methods, the scheme offers some advantages of less mechanical and optical complexity and avoids expensive and exotic sensor technologies. In free-space optical communications, the transmit beam must be accurately pointed toward the receiver in order to maintain the communication link. The current approaches to achieve this function call for part of the transmit beam to be split off and projected onto an optical sensor used to infer the pointed direction. This requires that the optical sensor be sensitive to the wavelength of the transmit laser. If a different transmit wavelength is desired, for example to obtain a source capable of higher data rates, this can become quite impractical because of the unavailability or inefficiency of sensors at these wavelengths. The innovation proposed here decouples this requirement by allowing any transmit wavelength to be used with any sensor. We have applied this idea to a particular system that transmits at the standard telecommunication wavelength of 1,550 nm and uses a silicon-based sensor, sensitive from 0.5 to 1.0 micrometers, to determine the pointing direction. The scheme shown in the figure involves integrating a low-power 980-nm reference or boresight laser beam coupled to the 1,550-nm transmit beam via a wavelength-division-multiplexed fiber coupler. Both of these signals propagate through the optical fiber where they achieve an extremely high level of co-alignment before they are launched into the telescope. The telescope uses a dichroic beam splitter to reflect the 980- nm beam onto the silicon image sensor (a quad detector, charge-coupled device, or active-pixel-sensor array) while the 1,550- nm signal beam is transmitted through the optical assembly toward the remotely located receiver. Since the 980-nm reference signal originates from the same single-mode fiber-coupled source as the transmit signal, its position on the sensor is used to accurately determine the propagation direction of the transmit signal. The optics are considerably simpler in the proposed scheme due to the use of a single aperture for transmitting and receiving. Moreover, the issue of mechanical misalignment does not arise because the reference signal and transmitted laser beams are inherently co-aligned. The beam quality of the 980-nm reference signal used for tracking is required to be circularly symmetric and stable at the tracking-plane sensor array in order to minimize error in the centroiding algorithm of the pointing system. However, since the transmit signal is delivered through a fiber that supports a single mode at 1,550 nm, propagation of higher order 980-nm modes is possible. Preliminary analysis shows that the overall mode profile is dominated by the fundamental mode, giving a near symmetric profile. The instability of the mode was also measured and found to be negligible in comparison to the other error contributions in the centroid position on the sensor array.

Wright, Malcolm↗
DOE OSTI2026

Atomic Evolution of Hydrogen Intercalation Wave Dynamics in Palladium Nanocrystals Revealed by Liquid-Phase Transmission Electron Microscopy

Solute-intercalation-induced phase separation creates spatial heterogeneities in host materials, a phenomenon ubiquitous in batteries, hydrogen storage, and other energy devices. Despite many efforts, probing intercalation processes at the atomic scale has been a significant challenge. By utilizing liquid-phase transmission electron microscopy (TEM), we study hydrogen (de)intercalation in palladium nanocrystals as a model system and have achieved unprecedented atomic-resolution imaging of hydrogen intercalation wave dynamics. Our observations reveal that intercalation wave mechanisms, instead of shrinking-core mechanisms, prevail at ambient temperature for palladium nanocubes ranging from ∼60 nm down to ∼10 nm. Systematic image analysis uncovers the atomic evolution of the hydrogen intercalation wave, transitioning from nonplanar and inclined boundaries to those closely aligned with {100} planes. Our kinetic Monte Carlo simulations demonstrate that the observed intercalation wave dynamics correspond to sorption pathways minimizing the lattice mismatch strain at the phase boundary. In conclusion, unveiling the atomic intercalation pathways holds profound implications for engineering intercalation-mediated devices and advancements in energy sciences.

Lee, Daewon [Lawrence Berkeley National Laboratory↗
DOE OSTI2014

Molecular Electronic Level Alignment at Weakly Coupled Organic Film/Metal Interfaces

Electronic level alignment at interfaces of molecular materials with inorganic semiconductors and metals controls many interfacial phenomena. How the intrinsic properties of the interacting systems define the electronic structure of their interface remains one of the most important problems in molecular electronics and nanotechnology that can be solved through a combination of surface science experimental techniques and theoretical modeling. In this article, we address this fundamental problem through experimental and computational studies of molecular electronic level alignment of thin films of C6F6 on noble metal surfaces. The unoccupied electronic structure of C6F6 is characterized with single molecule resolution using low-temperature scanning tunneling microscopy-based constant-current distance-voltage spectroscopy. The experiments are performed on several noble metal surfaces with different work functions and distinct surface-normal projected band structures. In parallel, the electronic structures of the quantum wells (QWs) formed by the lowest unoccupied molecular orbital state of the C6F6 monolayer and multilayer films and their alignment with respect to the vacuum level of the metallic substrates are calculated by solving the Schrödinger equation for a semiempirical one-dimensional (1D) potential of the combined system using input from density functional theory. Our analysis shows that the level alignment for C6F6 molecules bound through weak van der Waals interactions to noble metal surfaces is primarily defined by the image potential of metal, the electron affinity of the molecule, and the molecule surface distance. We expect the same factors to determine the interfacial electronic structure for a broad range of molecule/metal interfaces.

Environmental Molecular Sciences Laboratory↗
DOE OSTI2016

Inference from the small scales of cosmic shear with current and future Dark Energy Survey data

Cosmic shear is sensitive to fluctuations in the cosmological matter density field, including on small physical scales, where matter clustering is affected by baryonic physics in galaxies and galaxy clusters, such as star formation, supernovae feedback and AGN feedback. While muddying any cosmological information that is contained in small scale cosmic shear measurements, this does mean that cosmic shear has the potential to constrain baryonic physics and galaxy formation. We perform an analysis of the Dark Energy Survey (DES) Science Verification (SV) cosmic shear measurements, now extended to smaller scales, and using the Mead et al. 2015 halo model to account for baryonic feedback. While the SV data has limited statistical power, we demonstrate using a simulated likelihood analysis that the final DES data will have the statistical power to differentiate among baryonic feedback scenarios. We also explore some of the difficulties in interpreting the small scales in cosmic shear measurements, presenting estimates of the size of several other systematic effects that make inference from small scales difficult, including uncertainty in the modelling of intrinsic alignment on nonlinear scales, `lensing bias', and shape measurement selection effects. For the latter two, we make use of novel image simulations. While future cosmic shear datasets have the statistical power to constrain baryonic feedback scenarios, there are several systematic effects that require improved treatments, in order to make robust conclusions about baryonic feedback.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

Meso-Structured Polymer Electrolyte Fuel Cell Electrode

Increasing the utilization of Pt and Pt alloy catalysts in polymer electrolyte fuel cell cathodes is critical to improving the high power density operation, particularly at low Pt loadings. State of the art electrodes are fabricated in an ink deposition process that leads to uncontrolled electrode architecture with random aggregates of functional domains (catalyst, ionomer, and pore volume) (1). The randomness in the domains induces high tortuosity transport pathways for ions and fluids, which cause severe transport resistance during high current density operation. Thin ionomer films cause additional transport resistance and poisoning of the Pt catalyst, which becomes more significant at low Pt loadings. Reducing the amount of ionomer in the catalyst domain without affecting the ionic transport resistance is key to improving the utilization of the Pt and reducing the transport resistance at low Pt loading. Rational design of the electrode structure with controlled low tortuous ionic transport pathways could improve performance. The introduction of the ionomer pathways could also enable reduction of the ionomer volume in the catalyst domain, reducing the transport resistance. Middelmen et al. proposed electrode structures consisting of aligned components in a low tortuosity configuration to improve performance (2). In this work, we present an alternative electrode structure based on a vertically aligned array of Nafion pillars in the cathode catalyst layer, as shown in Figure 1a. Figure 1b shows the SEM image of the Nafion pillars. Furthermore, Pt supported on carbon catalyst was deposited on the Nafion pillars to fabricate a meso-structured electrode. Nafion pillars provide high conductive and low tortuous pathways for protons, reducing the effective transport distance, and enabling reduction of the ionomer binder in the catalyst domain.

25 ENERGY STORAGE↗
DOE OSTI2016

Full report of laser doppler velocimetry (Het-V) data, results , and analysis for pRad shot 0632

This was a collaborative shot with AWE investigators Paul Willis-Patel, David Bell, Seth Grant, David Tarr, and James Richley. The shot was assembled in Los Alamos, after which David Bell set up the probe holder and finalized the alignment. The probe holder location and configuration was modified from previous years to make room for the laser illuminated visible imaging diagnostic. The LANL pRad PDV team was Dale Tupa, Amy Tainter, and Patrick Medina. This shot had three PDV probes: one aimed at the center, one aimed at a feature, one aimed at the reverse side of the shot. The shot also had 9 points of a spectroscopy diagnostic. The pRad team helped set up and field the spectroscopy, but did not help with any data analysis. (The support documentation for the PDV results includes a timing map for the spectroscopy.) Please direct questions on the velocimetry to Dale Tupa or Amy Tainter. The shot radiographs were classified, but the data from the optical diagnostics are not.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2021

Cloud Droplet Measurement System for the ARM Tethered Balloon System (TBS) Field Campaign Report

The Mesa Photonics' cloud droplet measurement system (CDMS) performs in situ measurement of droplet size distribution and droplet number density in clouds. These characteristics are important cloud microphysical properties that are critical input parameters for atmospheric models and are also useful for proper calibration and validation of performance of other atmospheric measurement instrumentation. This small campaign was the first project (out of two) that involved integration of the CDMS into the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) user facility’s tethered balloon system (TBS) and its initial testing at the ARM Southern Great Plains (SGP) atmospheric observatory. The follow-up campaign (AFC07016) involved testing of the CDMS under relevant conditions at the third ARM Mobile Facility (AMF3) at Oliktok Point, Alaska and making in situ measurements in clouds. The goal of this small field campaign was to deploy the CDMS on the ARM TBS, demonstrate its integrity and compatibility with the TBS, and test the wireless telecommunication system in preparation for subsequent in-cloud measurements at ARM’s North Slope of Alaska (NSA) observatory at Utqiagvik (formerly Barrow). The specific technical objectives included: (1) Integration of the Mesa Photonics' CDMS into the ARM TBS, (2) testing of the wireless telecommunication system of the CDMS, (3) evaluating the data acquisition software and image processing algorithms especially under high-background-illumination conditions, and (4) testing the ruggedness of the instrument's optical alignment and other performance characteristics. All objectives have been successfully met. The mounting hardware was designed and built mostly at Sandia National Laboratories (SNL), which allowed reliable mounting of the CDMS on the TBS and co-locating the CDMS with other instruments. The field tests were performed by the principal investigator (PI) in collaboration with the TBS operational crew led by D. Dexheimer. The field testing demonstrated good compatibility of the CDMS with the TBS. During the TBS flights, the crew did not experience any operational issues with the CDMS. The instrument demonstrated reliable operational characteristics, including sufficient battery life and good thermal management. The wireless telecommunication system has been successfully tested at TBS flight altitudes of up to 1000 m. During all flights, the CDMS raw data were wirelessly transmitted to the ground station and processed in real time. The ruggedness of the instrument's optical alignment was evaluated by performing calibration of the CDMS (using Mesa Photonics' fixed-size monodisperse droplet generator) before and after the campaign. The calibration was stable within the instrument's measurement precision. In summary, the campaign demonstrated good compatibility of the Mesa Photonics' CDMS with the ARM TBS. The flight tests confirmed the mechanical integrity of the CDMS and stability of its optical layout, as well as reliability of the wireless telecommunication system. Successful completion of this campaign provided a solid basis for the next campaign (AFC07016, November 2020), that involved testing of the CDMS during in-cloud TBS flights at AMF3 at Oliktok Point.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2019

Parametric Survey of a Natural Gas-Air Rotating Detonation Engine at Elevated Pressure

Detonation dynamics in a rotating detonation engine were studied to characterize the operability and performance of rotating detonation based pressure gain combustion systems at application-relevant conditions. The combustor was developed to operate with natural gas and air as the primary propellants at elevated chamber pressures and high air pre-heat temperatures representative of land based power generation systems. Measurements of chamber wave dynamics were performed using high-frequency pressure transducers and high speed imaging of broadband combustion luminescence. The rotating detonation engine was tested across a broad range of flow conditions to determine how operating parameters affect the propagation of detonation waves in the combustor. Enriching the air with additional oxygen was shown to broaden the range of conditions that allowed detonation fronts to stably propagate within the chamber, though all tested conditions exhibited counter-rotating waves. This range was shifted to lower oxygen content by increasing the oxidizer preheat temperature, which suggests a dependence on the chemical kinetics of the reactant mixture. Some conditions exhibited modulations in pressure fluctuation amplitude and frequency measured by chamber pressure probes. Analysis of high speed images identified the source of the modulation as the intersection point of the counter-propagating detonation waves rotating to align with different pressure measurement ports throughout the test duration.

20 FOSSIL-FUELED POWER PLANTS↗
NASA NTRS1985

Observations of E and F region Mg(+) from Spacelab 1

Images of airglow at 2800 A were taken on the Spacelab 1 Shuttle mission and have been interpreted to be solar resonant emission of magnesium ions. On two orbital passes, observations were made near the magnetic equator while observing in the 2800-A channel. The observations were made near the sunset terminator (approximately 1800 LT), in winter (1983, day 335). Three separate emission clouds were observed, all of which extended well into the F region. The location of the clouds in horizontal space is shown. The processed images have been pseudocolored to highlight the intensity distribution in the clouds. Observations included clouds with apparent magnetic-field aligned striations. Bright emissions were observed at the magnetic equator, at 12-deg north magnetic latitude, and at 12-deg south magnentic latitude. Cloud-center brightnesses varied between 680 rayleighs and 1700 rayleighs.

Mende, S. B.↗