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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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962 records · Page 54
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Capturing plume behavior in complex terrain: an overview of the Nevada National Security Site Meteorological Experiment (METEX21)

METEX21 was an atmospheric tracer release experiment executed at the Department of Energy’s Nevada National Security Site (NNSS) in the southwestern U.S to study terrain-induced wind and thermodynamic conditions that influence local-scale (<5-km) plume transport under varying atmospheric forcing conditions. Meteorological observations were collected using 10-m tall meteorological towers, 2-m tall tripods with 3-d sonic anemometers, a 3-m tall eddy covariance flux tower, Doppler profiling lidars, Doppler scanning lidars, weather-balloon launched radiosondes, and a tethered balloon equipped with wind, temperature, and aerosol sensors at heights up to 800 m. A smoke tracer was released along three transects in the horizontal and vertical directions and observed with video cameras, aerosol sensors and lidars (via aerosol backscatter). The observations showed evidence of large-scale/synoptic transience as well as local-scale upslope and downslope flows, along-axis valley flows, recirculation eddies on leeward slopes, and periods of strong shear and veer aloft. The release days were classified as either synoptically-driven or locally-driven, and a single case day is presented in detail for each. Synoptically-forced days show relatively narrow smoke plumes traveling down the valley from north to south (with the predominant wind direction), with little deviation in transport direction regardless of the elevation or ground locations of the smoke releases, except near the presence of leeside recirculation eddies. Locally-forced days exhibit a wider range of plume behavior due to the combination of thermally-induced valley and slope flows, which are often flowing in different cardinal directions, and wind shear found aloft at higher altitudes and elevations. We saw evidence of smoke lofting on top of the mesas due to strong upslope flows on these days. A major finding of this experiment was the effectiveness of scanning lidars to measure 2-dimensional plume transport out to a 2–3 km distance; much farther than could be visibly observed. METEX21 was the first of three planned tracer experiments at NNSS, and future experiments will incorporate multiple tracers to improve individual plume identification so that finer resolution flow details can be attained from these measurements, as well as deploy a larger suite of meteorological instrumentation, including more temperature profiling data.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Fabrication of OMT-Coupled Kinetic Inductance Detector for CMB Detection

Future cosmic microwave background (CMB) experiments, including the large scale ground-based Stage Four CMB Experiment (CMB-S4), satellites, and balloons, aim to map the CMB to an unprecedented precision in order to answer several key questions in cosmology. However, to reach the target noise sensitivity, more than 100,000 detectors will be needed. Arrays of kinetic inductance detectors (KIDs) are a promising alternative for experiments that require large number of detectors due to the intrinsic multiplexing capabilities. We present the fabrication procedure for a prototype planar orthomode transducer (OMT)-coupled multi-color KID array optimized for 220/270 GHz frequency bands. These devices are made from silicon-on-insulator wafers to provide a low-loss substrate for the KIDs. The OMT couples the two polarizations of light from a wide-band feedhorn to separate Nb/SiN/Nb microstrip lines, which are then coupled to Al/Nb lumped-element KIDs (LEKIDs). The silicon on the backside of the OMT is etched away using deep reactive ion etch to release the OMT membrane to enable operation over a wide bandwidth. Finally, the buried oxide is removed underneath the KID capacitors in order to minimize two-level system noise and loss mitigation. We achieved a good yield (> 80%) on our prototype devices.

47 OTHER INSTRUMENTATION↗
NASA NTRS2008

The Bess-Polar II Long Duration Flight Above Antarctica

The Balloon-borne Experiment with a Superconducting Spectrometer, BESS, has been developed to study elementary particle phenomena in the early universe through measurements of low energy antiprotons to investigate their origin and through a search for antihelium. The BESS collaboration carried out nine northern latitude flights between 1993 and 2002. BESS-Polar is an advanced program of the BESS collaboration to study these topics with much greater precision using long duration flights above Antarctica. The BESS-Polar spectrometer was successfully developed to accumulate much larger numbers of events during long duration flights around the South Pole. Approximately a factor of four reductions in the amount of material in the particle beam enables measurement of much lower energy antiprotons down to 100 MeV (at top of atmosphere). The first BESS-Polar flight (BESS-Polar I) of 8.5 days was carried out above Antarctica in December 2004. recording 900 million cosmic-ray events. The second BESS-Polar flight (BESS-Polar 11) was successfully carried out in the austral summer season of 2007-2008. Based on experience with BESS-Polar I, the spectrometer was improved in performance and achieved long term stability during the flight. A newly constructed magnet with a larger liquid He capacity and improved thermal insulation and an upgraded data storage system with larger capacity of hard disk drives (HDDs) enabled longer observation time. BESS-Polar II was launched on December 22, 2007 from Williams Field, McMurdo Station, in Antarctica. The spectrometer worked properly and observed cosmic rays for about 24.5 days at float altitude, recording 4.6 billion events on the HDDs until the limit of the magnet operation was reached on January 16, 2008. The flight was terminated and the spectrometer was safely landed on the West Antarctic ice sheet (1000 km from the South Pole) on January 21, 2008. Here, the BESS-Polar instrument is discussed, highlighting improvements made for BESS-Polar II, and overviews of the flight and performance are reported.

Sasaki, Makoto↗
NASA NTRS2010

NASA Tech Briefs, May 2010

Topics covered include: Instrument for Analysis of Greenland's Glacier Mills Cryogenic Moisture Apparatus; A Transportable Gravity Gradiometer Based on Atom Interferometry; Three Methods of Detection of Hydrazines; Crossed, Small-Deflection Energy Analyzer for Wind/Temperature Spectrometer; Wavefront Correction for Large, Flexible Antenna Reflector; Novel Micro Strip-to-Waveguide Feed Employing a Double-Y Junction; Thin-Film Ferro Electric-Coupled Microstripline Phase Shifters With Reduced Device Hysteresis; Two-Stage, 90-GHz, Low-Noise Amplifier; A 311-GHz Fundamental Oscillator Using InP HBT Technology; FPGA Coprocessor Design for an Onboard Multi-Angle Spectro-Polarimetric Imager; Serrating Nozzle Surfaces for Complete Transfer of Droplets; Turbomolecular Pumps for Holding Gases in Open Containers; Triaxial Swirl Injector Element for Liquid-Fueled Engines; Integrated Budget Office Toolbox; PLOT3D Export Tool for Tecplot; Math Description Engine Software Development Kit; Astronaut Office Scheduling System Software; ISS Solar Array Management; Probabilistic Structural Analysis Program; SPOT Program; Integrated Hybrid System Architecture for Risk Analysis; System for Packaging Planetary Samples for Return to Earth; Offset Compound Gear Drive; Low-Dead-Volume Inlet for Vacuum Chamber; Simple Check Valves for Microfluidic Devices; A Capillary-Based Static Phase Separator for Highly Variable Wetting Conditions; Gimballing Spacecraft Thruster; Finned Carbon-Carbon Heat Pipe with Potassium Working Fluid; Lightweight Heat Pipes Made from Magnesium; Ceramic Rail-Race Ball Bearings; Improved OTEC System for a Submarine Robot; Reflector Surface Error Compensation in Dual-Reflector Antennas; Enriched Storable Oxidizers for Rocket Engines; Planar Submillimeter-Wave Mixer Technology with Integrated Antenna; Widely Tunable Mode-Hop-Free External-Cavity Quantum Cascade Laser; Non-Geiger-Mode Single-Photon Avalanche Detector with Low Excess Noise; Using Whispering-Gallery-Mode Resonators for Refractometry; RF Device for Acquiring Images of the Human Body; Reactive Collision Avoidance Algorithm; Fast Solution in Sparse LDA for Binary Classification; Modeling Common-Sense Decisions in Artificial Intelligence; Graph-Based Path-Planning for Titan Balloons; Nanolaminate Membranes as Cylindrical Telescope Reflectors; Air-Sea Spray Airborne Radar Profiler Characterizes Energy Fluxes in Hurricanes; Large Telescope Segmented Primary Mirror Alignment; and Simplified Night Sky Display System.

Source record↗
DOE OSTI2024

New millimeter-wave diagnostics to locally probe internal density and magnetic field fluctuations in National Spherical Torus Experiment-Upgrade (invited)

A set of new millimeter-wave diagnostics will deliver unique measurement capabilities for National Spherical Torus Experiment-Upgrade to address a variety of plasma instabilities believed to be important in determining thermal and particle transport, such as micro-tearing, global Alfvén eigenmodes, kinetic ballooning, trapped electron, and electron temperature gradient modes. These diagnostics include a new integrated intermediate-k Doppler backscattering (DBS) and cross-polarization scattering (CPS) system (four channels, 82.5–87 GHz) to measure density and magnetic fluctuations, respectively. The system can access reasonably large normalized wavenumbers k θ ρ s ranging from ≤0.5 to 15 (where ion sound gyroradius ρ s = 1 cm and k θ is the binormal density turbulence wavenumber). The system addresses the challenges for making useful DBS/CPS measurements with a remote control of launch polarization (X- or O-mode), probed wavenumber, polarization match of the launch beam with the edge magnetic field pitch angle, and beam steering of the launched beam for wave-vector alignment. In addition, a low-k DBS system consisting of eight fixed frequencies (34–52 GHz) and four tunable frequencies (55–75 GHz) for low-k density turbulence and fast ion physics will be located at a nearby port location. Finally, the combined systems cover the near LCFS and pedestal regions (34–52 GHz), the pedestal or mid-radius (50–75 GHz), and core plasmas (82.5–87 GHz).

47 OTHER INSTRUMENTATION↗
DOE OSTI2018

Constraints on the diffuse high-energy neutrino flux from the third flight of ANITA

The Antarctic Impulsive Transient Antenna, a NASA long-duration balloon payload, searches for radio emission from interactions of ultrahigh-energy neutrinos in polar ice. The third flight of the Antarctic Impulsive Transient Antenna was launched in December 2014 and completed a 22-day flight. Here, we present the results of three analyses searching for Askaryan radio emission of neutrino origin. In the most sensitive of the analyses, we find one event in the signal region on an expected background of 0.7$+0.5\atop{-0.3}$. Though consistent with the background estimate, the event remains compatible with a neutrino hypothesis even after additional postunblinding scrutiny.

47 OTHER INSTRUMENTATION↗
NASA NTRS2004

Curved-Focal-Plane Arrays Using Deformed-Membrane Photodetectors

A versatile and simple approach to the design and fabrication of curved-focal-plane arrays of silicon-based photodetectors is being developed. This approach is an alternative to the one described in "Curved Focal-Plane Arrays Using Back- Illuminated High-Purity Photodetectors" (NPO-30566), NASA Tech Briefs, Vol. 27, No. 10 (October 2003), page 10a. As in the cited prior article, the basic idea is to improve the performance of an imaging instrument and simplify the optics needed to obtain a given level of performance by making an image sensor (in this case, an array of photodetectors) conform to a curved focal surface, instead of designing the optics to project an image onto a flat focal surface. There is biological precedent for curved-focal-surface designs: retinas - the image sensors in eyes - conform to the naturally curved focal surfaces of eye lenses. The present approach is applicable to both front-side- and back-side-illuminated, membrane photodetector arrays and is being demonstrated on charge-coupled devices (CCDs). The very-large scale integrated (VLSI) circuitry of such a CCD or other array is fabricated on the front side of a silicon substrate, then the CCD substrate is attached temporarily to a second substrate for mechanical support, then material is removed from the back to obtain the CCD membrane, which typically has a thickness between 10 and 20 m. In the case of a CCD designed to operate in back-surface illumination, delta doping can be performed after thinning to enhance the sensitivity. This approach is independent of the design and method of fabrication of the front-side VLSI circuitry and does not involve any processing of a curved silicon substrate. In this approach, a third substrate would be prepared by polishing one of its surfaces to a required focal-surface curvature. A CCD membrane fabricated as described above would be pressed against, deformed into conformity with, and bonded to, the curved surface. The technique used to press and bond the CCD membrane would depend on the nature of the supporting material (see figure). For example, if the third substrate were made of quartz frit, the substrate would be prepared by suffusing it with epoxy. Then one would take advantage of the porosity of the frit by applying a partial vacuum to the opposite surface of the frit, causing atmospheric pressure to push the CCD membrane against the curved surface. The curing of the epoxy would bond the CCD membrane to the curved surface. Alternatively, if the third substrate were made of a nonporous material, the curved substrate surface would be prepared by coating it with a wax or an uncured epoxy. The CCD membrane would be pressed against the coated, curved surface by use of a suitably pressurized balloon. The CCD membrane would then become bonded to the curved surface by curing of the epoxy or freezing of the wax.

Nikzad, Shouleh↗
DOE OSTI2017

A New Limit on CMB Circular Polarization from SPIDER

We present a new upper limit on cosmic microwave background (CMB) circular polarization from the 2015 flight of Spider, a balloon-borne telescope designed to search for B-mode linear polarization from cosmic inflation. Although the level of circular polarization in the CMB is predicted to be very small, experimental limits provide a valuable test of the underlying models. By exploiting the nonzero circular-to-linear polarization coupling of the half-wave plate polarization modulators, data from Spider's 2015 Antarctic flight provide a constraint on Stokes V at 95 and 150 GHz in the range 33<ℓ<307. No other limits exist over this full range of angular scales, and Spider improves on the previous limit by several orders of magnitude, providing 95% C.L. constraints on ℓ(ℓ+1)C{sub ℓ}{sup VV}/(2π) ranging from 141 to 255 μK{sup 2} at 150 GHz for a thermal CMB spectrum. As linear CMB polarization experiments become increasingly sensitive, the techniques described in this paper can be applied to obtain even stronger constraints on circular polarization.

79 ASTRONOMY AND ASTROPHYSICS↗