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NASA NTRS2014

Spinoff 2013

Topics covered include: Innovative Software Tools Measure Behavioral Alertness; Miniaturized, Portable Sensors Monitor Metabolic Health; Patient Simulators Train Emergency Caregivers; Solar Refrigerators Store Life-Saving Vaccines; Monitors Enable Medication Management in Patients' Homes; Handheld Diagnostic Device Delivers Quick Medical Readings; Experiments Result in Safer, Spin-Resistant Aircraft; Interfaces Visualize Data for Airline Safety, Efficiency; Data Mining Tools Make Flights Safer, More Efficient; NASA Standards Inform Comfortable Car Seats; Heat Shield Paves the Way for Commercial Space; Air Systems Provide Life Support to Miners; Coatings Preserve Metal, Stone, Tile, and Concrete; Robots Spur Software That Lends a Hand; Cloud-Based Data Sharing Connects Emergency Managers; Catalytic Converters Maintain Air Quality in Mines; NASA-Enhanced Water Bottles Filter Water on the Go; Brainwave Monitoring Software Improves Distracted Minds; Thermal Materials Protect Priceless, Personal Keepsakes; Home Air Purifiers Eradicate Harmful Pathogens; Thermal Materials Drive Professional Apparel Line; Radiant Barriers Save Energy in Buildings; Open Source Initiative Powers Real-Time Data Streams; Shuttle Engine Designs Revolutionize Solar Power; Procedure-Authoring Tool Improves Safety on Oil Rigs; Satellite Data Aid Monitoring of Nation's Forests; Mars Technologies Spawn Durable Wind Turbines; Programs Visualize Earth and Space for Interactive Education; Processor Units Reduce Satellite Construction Costs; Software Accelerates Computing Time for Complex Math; Simulation Tools Prevent Signal Interference on Spacecraft; Software Simplifies the Sharing of Numerical Models; Virtual Machine Language Controls Remote Devices; Micro-Accelerometers Monitor Equipment Health; Reactors Save Energy, Costs for Hydrogen Production; Cameras Monitor Spacecraft Integrity to Prevent Failures; Testing Devices Garner Data on Insulation Performance; Smart Sensors Gather Information for Machine Diagnostics; Oxygen Sensors Monitor Bioreactors and Ensure Health and Safety; Vision Algorithms Catch Defects in Screen Displays; and Deformable Mirrors Capture Exoplanet Data, Reflect Lasers.

Source record↗

NASA NTRS1987

Soft x ray window encapsulant for HgI2 detectors

HgI2 is an excellent semiconductor material for a low energy, room temperature x-ray spectrometer. The high values of the atomic numbers for its constituent elements gives high x-ray and gamma ray stopping power. The band gap of HgI2 is significantly higher than other commonly used semiconductors. Owing to the large value band gap, the leakage current for HgI2 devices is smaller, thus allowing low noise performance. Devices fabricated from HgI2 crystals have demonstrated energy resolution sufficient to distinguish the x-ray emission from the neighboring elements on the periodic table. Also the power requirements of HgI2 are very low. These characteristics make a HgI2 spectrometer an ideal component in a satellite based detection system. Unfortunately, HgI2 crystals tend to deteriorate with time, even if protected by standard semiconductor encapsulants. This degradation ruins the performance of the device in terms of its energy resolution and pulse amplitude. The degrading mechanism is believed to be material loss occurring from below the electrodes, due to high vapor pressure of HgI2 at room temperature. To address this major obstacle to rapid expansion of HgI2 technology, a research program aimed at improving device stability by encapsulation with inert polymeric materials was carried out. The program focused specifically on optimizing the encapsulant materials and their deposition techniques. The principal objectives for this program were device encapsulation, device testing, and accelerated testing to ensure very long term stability of these high resolution sensors. A variety of encapsulants were investigated with the selection criteria based on their chemical diffusion barrier properties, mechanical stability, reactivity, and morphology of encapsulant films. The investigation covered different classes of encapsulants including solvent based encapsulants, vapor deposited encapsulants, and plasma polymerized encapsulants. A variety of characterization techniques were employed to examine their effectiveness in stabilizing HgI2 devices; these included permeability evaluation, vacuum and heat testing, scanning electron microscopy (SEM) as well as studying the detector performance of coated detectors. The plasma polymerized films appear to have entirely solved the HgI2 degradation problem. Another achievement of this program was the development of an accelerated testing technique which correlates extremely well with long term tesing.

Entine, G.↗

DOE OSTI2018

Structure-induced switching of interpolymer adhesion at a solid–polymer melt interface

In this paper, we report a link between the interfacial structure and adhesive property of homopolymer chains physically adsorbed (i.e., via physisorption) onto solids. Polyethylene oxide (PEO) was used as a model and two different chain conformations of the adsorbed polymer were created on silicon substrates via the well-established Guiselin's approach: “flattened chains” which lie flat on the solid and are densely packed, and “loosely adsorbed polymer chains” which form bridges jointing up nearby empty sites on the solid surface and cover the flattened chains. We investigated the adhesion properties of the two different adsorbed chains using a custom-built adhesion testing device. Bilayers of a thick PEO overlayer on top of the flattened chains or loosely adsorbed chains were subjected to the adhesion test. The results revealed that the flattened chains do not show any adhesion even with the chemically identical free polymer on top, while the loosely adsorbed chains exhibit adhesion. Neutron reflectivity experiments corroborated that the difference in the interfacial adhesion is not attributed to the interfacial brodening at the free polymer–adsorbed polymer interface. Instead, coarse-grained molecular dynamics simulation results suggest that the tail parts of the loosely adsorbed chains act as “connector molecules”, bridging the free chains and substrate surface and improving the interfacial adhesion. Finally, these findings not only shed light on the structure–property relationship at the interface, but also provide a novel approach for developing sticking/anti-sticking technologies through precise control of the interfacial polymer nanostructures.

36 MATERIALS SCIENCE↗

DOE OSTI2016

Mini array of quantum Hall devices based on epitaxial graphene

Series connection of four quantum Hall effect (QHE) devices based on epitaxial graphene films was studied for realization of a quantum resistance standard with an up-scaled value. The tested devices showed quantum Hall plateaux R{sub H,2} at a filling factor v = 2 starting from a relatively low magnetic field (between 4 T and 5 T) when the temperature was 1.5 K. The precision measurements of quantized Hall resistance of four QHE devices connected by triple series connections and external bonding wires were done at B = 7 T and T = 1.5 K using a commercial precision resistance bridge with 50 μA current through the QHE device. The results showed that the deviation of the quantized Hall resistance of the series connection of four graphene-based QHE devices from the expected value of 4×R{sub H,2} = 2 h/e{sup 2} was smaller than the relative standard uncertainty of the measurement (<1 × 10{sup −7}) limited by the used resistance bridge.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

NASA NTRSDate not supplied

TPSAS-NF1676L-33512-DND

INTRODUCTION: In an effort to quantify the predictive capability of the Livermore Software Technology Corporation (LSTC)-provided Hybrid III (small female, mid-size male, and large male) anthropomorphic test device (ATD) finite element models (FEMs) within aerospace loading environments, the National Aeronautics and Space Administration (NASA) performed a series of sled tests with the isolated head-neck complex of each ATD. These tests and subsequent modeling efforts revealed significant deficiencies in the large male head neck FEM. Differences in both the shape and material properties between the FEM and the physical ATD were identified. In order to improve the predictive response of the FEM, a model development effort was undertaken to update the head-neck complex to better represent the geometric and material properties of the physical ATD.METHODS: To better match the physical geometry, a new neck component model was meshed and implemented into the Hybrid III large male head-neck complex. The updated geometry and weight were verified against measurements of the physical ATD to insure accuracy. The primary source of material discrepancy between the physical ATD and FEM was found to be in the material definition of the rubber neck pucks. Using LS-Opt the material properties of this part were calibrated to match physical response of the head-neck complex in the isolated head-neck testing performed. RESULTS AND DISCUSSION: The updated geometry and calibrated material properties were shown to significantly improve the FEM predictive accuracy under lateral, rear, and frontal impacts with combined horizontal and vertical loading. The results of this study demonstrate an effective means for improving ATD FEM response through isolated component level testing and material parameter optimization. The improved and quantified accuracy of the Hybrid III large male FEM head-neck complex stemming from with work lends to confidence in its future use for occupant protection evaluation of large male occupants

J Putnam↗

DOE OSTI2015

TASK 2: QUENCH ZONE SIMULATION

Aerojet Rocketdyne (AR) has developed an innovative gasifier concept incorporating advanced technologies in ultra-dense phase dry feed system, rapid mix injector, and advanced component cooling to significantly improve gasifier performance, life, and cost compared to commercially available state-of-the-art systems. A key feature of the AR gasifier design is the transition from the gasifier outlet into the quench zone, where the raw syngas is cooled to ~ 400°C by injection and vaporization of atomized water. Earlier pilot plant testing revealed a propensity for the original gasifier outlet design to accumulate slag in the outlet, leading to erratic syngas flow from the outlet. Subsequent design modifications successfully resolved this issue in the pilot plant gasifier. In order to gain greater insight into the physical phenomena occurring within this zone, AR developed a cold flow simulation apparatus with Coanda Research & Development with a high degree of similitude to hot fire conditions with the pilot scale gasifier design, and capable of accommodating a scaled-down quench zone for a demonstration-scale gasifier. The objective of this task was to validate similitude of the cold flow simulation model by comparison of pilot-scale outlet design performance, and to assess demonstration scale gasifier design feasibility from testing of a scaled-down outlet design. Test results did exhibit a strong correspondence with the two pilot scale outlet designs, indicating credible similitude for the cold flow simulation device. Testing of the scaled-down outlet revealed important considerations in the design and operation of the demonstration scale gasifier, in particular pertaining to the relative momentum between the downcoming raw syngas and the sprayed quench water and associated impacts on flow patterns within the quench zone. This report describes key findings from the test program, including assessment of pilot plant configuration simulations relative to actual results on the pilot plant gasifier and demonstration plant design recommendations, based on cold flow simulation results.

01 COAL, LIGNITE, AND PEAT↗

DOE OSTI2018

Report on Design and Failure Limits of SiC/SiC and FeCrAl ATF Cladding Concepts under RIA

Pellet-cladding mechanical interaction (PCMI) is a possible failure scenario during a postulated reactivity-initiated accident (RIA). This report summarizes fiscal year 2018 research activities that were undertaken to evaluate the PCMI-like hoop strain–driven mechanical response of accident tolerant fuel cladding candidates of silicon carbide fiber/silicon carbide matrix composite (SiC/SiC) and iron–chromium–aluminum (FeCrAl) tube specimens. To achieve various RIA-like conditions, the modified-burst test device developed during fiscal years 2016 and 2017 was used. A heating capability was also added to the system for high-temperature testing of FeCrAl samples.The first section of this report assesses the accuracy of the two-dimensional digital image correlation calculated strain values for tube samples. The speckle patterns are computer generated in a two-dimensional plane, and the generated images were wrapped into a cylindrical surface for the validation using digital image correlation technique on curved geometries. Subsequent sections address the failure behavior of SiC/SiC composites and long-term heat treated and as-drawn FeCrAl alloy tubes at various strain rates relevant to the postulated RIA events. In the last part, the effect of possible design parameters of failure strain and the strain rate are discussed for SiC/SiC composites and FeCrAl alloys during the PCMI phase of RIA.Future work is planned to develop and design safety tests for accident tolerant fuel cladding candidates and the advanced fuel forms with respect to their transient responses. A broader perspective on the mechanical behavior of the unirradiated and irradiated accident tolerant fuel cladding candidates will be developed using the modified-burst test and other mechanical tests.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗

NASA NTRS1983

Limited flight test experience with a laser transit velocimeter

Limited flight testing of a laser transit velocimeter provided insight into the problems associated with the use of such instruments for flight research. Although the device tested was not designed for flight application, it had certain features such as fiber optics and low laser power which are attractive in the airborne environment. During these tests, operation of the velocimeter was limited by insufficient concentrations of light-scattering particles and background light interference. Normal operation was observed when these conditions were corrected by utilizing cloud particles and flying at night. A comparison between the laser flow velocity measurements and corresponding pressure measurements is presented and shows a coarse correlation. Statistical bias due to turbulence in the flow is suspected to have affected the laser measurements.

Curry, R. E.↗

NASA NTRS1990

Peeled film GaAs solar cells for space power

Gallium arsenide (GaAs) peeled film solar cells were fabricated, by Organo-Metallic Vapor Phase Epitaxy (OMVPE), incorporating an aluminum arsenide (AlAs) parting layer between the device structure and the GaAs substrate. This layer was selectively removed by etching in dilute hydrofloric (HF) acid to release the epitaxial film. Test devices exhibit high series resistance due to insufficient back contact area. A new design is presented which uses a coverglass superstrate for structural support and incorporates a coplanar back contact design. Devices based on this design should have a specific power approaching 700 W/Kg.

Wilt, D. M.↗

NASA NTRS2006

Method and Apparatus for the Portable Identification Of Material Thickness And Defects Along Uneven Surfaces Using Spatially Controlled Heat Application

A method and apparatus for testing a material such as the water-wall tubes in boilers includes the use of a portable thermal line heater having radiation shields to control the amount of thermal radiation that reaches a thermal imager. A procedure corrects for variations in the initial temperature of the material being inspected. A method of calibrating the testing device to determine an equation relating thickness of the material to temperatures created by the thermal line heater uses empirical data derived from tests performed on test specimens for each material type, geometry, density, specific heat, speed at which the line heater is moved across the material and heat intensity.

Reilly, Thomas L.↗

NASA NTRS2011

High Broadband Spectral Resolving Transition-Edge Sensors for High Count-Rate Astrophysical Applications

We are developing arrays of transition-edge sensor (TES) X-ray detectors optimized for high count-rate solar astronomy applications where characterizing the high velocity motions of X-ray jets in solar flares is of particular interest. These devices are fabricated on thick Si substrates and consist of 35x35micron^2 TESs with 4.5micron thick, 60micron pitch, electroplated absorbers. We have tested devices fabricated with different geometric stem contact areas with the TES and surrounding substrate area, which allows us to investigate the loss of athermal phonons to the substrate. Results show a correlation between the stem contact area and a non-Gaussian broadening in the spectral line shape consistent with athermal phonon loss. When the contact area is minimized we have obtained remarkable board-band spectral resolving capabilities of 1.3 plus or minus 0.leV at an energy of 1.5 keV, 1.6 plus or minus 0.1 eV at 5.9 keV and 2.0 plus or minus 0.1 eV at 8 keV. This, coupled with a capability of accommodating 100's of counts per second per pixel makes these devices an exciting prospect of future x-ray astronomy applications.

Smith, Stephen↗

NASA NTRS1979

Diode step stress program for JANTX1N649-1

The effect of power/temperature step stress when applied to a variety of semiconductor devices is evaluated. A total of 48 samples were submitted to be processed. Control sample units were maintained for verification of the electrical parametric testing. The test circuit was used to power all of the test devices during the power/temperature stress conditions.

Source record↗

NASA NTRS2009

Metabolic Cost of Experimental Exercises

Although the type and duration of activity during decompression was well documented, the metabolic cost of 1665 subject-exposures with 8 activity profiles from 17 altitude decompression sickness (DCS) protocols at Brooks City-Base, TX from 1983-2005 was not determined. Female and male human volunteers (30 planned, 4 completed) performed activity profiles matching those 8 activity profiles at ground level with continuous monitoring of metabolic cost. A Cosmed K4b2 Cardio Pulmonary Exercise Testing device was used to measure oxygen uptake (VO2) during the profiles. The results show levels of metabolic cost to the females for the profiles tested varied from 4.3 to 25.5 ml/kg/min and from 3.0 to 12.0 ml/kg/min to the males. The increase in VO2 from seated rest to the most strenuous of the 8 activity profiles was 3.6-fold for the females and 2.8-fold for the males. These preliminary data on 4 subjects indicate close agreement of oxygen uptake for activity performed during many subject-exposures as published earlier. The relatively low average oxygen uptake required to perform the most strenuous activity may imply the need for adjustment of modeling efforts using metabolic cost as a risk factor. Better definition of metabolic cost during exposure to altitude, a critical factor in DCS risk, may allow refinement of DCS prediction models.

Webb, James T.↗

DOE OSTI2013

Magnetic Fe3O4@TiO2 Nanoparticles-based Test Strip Immunosensing Device for Rapid Detection of Phosphorylated Butyrylcholinesterase

An integrated magnetic nanoparticles-based test-strip immunosensing device was developed for rapid and sensitive quantification of phosphorylated butyrylcholinesterase (BChE), the biomarker of exposure to organophosphous pesticides (OP), in human plasma. In order to overcome the difficulty in scarce availability of OP-specific antibody, here magnetic Fe3O4@TiO2 nanoparticles were used and adsorbed on the test strip through a small magnet inserted in the device to capture target OP-BChE through selective binding between TiO2 and OP moiety. Further recognition was completed by horseradish peroxidase (HRP) and anti-BChE antibody (Ab) co-immobilized gold nanoparticles (GNPs). Their strong affinities among Fe3O4@TiO2, OP-BChE and HRP/Ab-GNPs were characterized by quartz crystal microbalance (QCM), surface plasmon resonance (SPR) and square wave voltammetry (SWV) measurements. After cutting off from test strip, the resulted immunocomplex (HRP/Ab-GNPs/OP-BChE/Fe3O4@TiO2) was measured by SWV using a screen printed electrode under the test zone. Greatly enhanced sensitivity was achieved by introduction of GNPs to link enzyme and antibody at high ratio, which amplifies electrocatalytic signal significantly. Moreover, the use of test strip for fast immunoreactions reduces analytical time remarkably. Coupling with a portable electrochemical detector, the integrated device with advanced nanotechnology displays great promise for sensitive, rapid and in-filed on-site evaluation of OP poisoning.

biomarkers↗

DOE OSTI2014

Radiochemically-Supported Microbial Communities: A Potential Mechanism for Biocolloid Production of Importance to Actinide Transport

Due to the legacy of Cold War nuclear weapons testing, the Nevada National Security Site (NNSS, formerly known as the Nevada Test Site (NTS)) contains millions of Curies of radioactive contamination. Presented here is a summary of the results of the first comprehensive study of subsurface microbial communities of radioactive and nonradioactive aquifers at this site. To achieve the objectives of this project, cooperative actions between the Desert Research Institute (DRI), the Nevada Field Office of the National Nuclear Security Administration (NNSA), the Underground Test Area Activity (UGTA), and contractors such as Navarro-Interra (NI), were required. Ultimately, fluids from 17 boreholes and two water-filled tunnels were sampled (sometimes on multiple occasions and from multiple depths) from the NNSS, the adjacent Nevada Test and Training Range (NTTR), and a reference hole in the Amargosa Valley near Death Valley. The sites sampled ranged from highly-radioactive nuclear device test cavities to uncontaminated perched and regional aquifers. Specific areas sampled included recharge, intermediate, and discharge zones of a 100,000-km2 internally-draining province, known as the Death Valley Regional Flow System (DVRFS), which encompasses the entirety of the NNSS/NTTR and surrounding areas. Specific geological features sampled included: West Pahute and Ranier Mesas (recharge zone), Yucca and Frenchman Flats (transitional zone), and the Western edge of the Amargosa Valley near Death Valley (discharge zone). The original overarching question underlying the proposal supporting this work was stated as: Can radiochemically-produced substrates support indigenous microbial communities and subsequently stimulate biocolloid formation that can affect radionuclides in NNSS subsurface nuclear test/detonation sites? Radioactive and non-radioactive groundwater samples were thus characterized for physical parameters, aqueous geochemistry, and microbial communities using both DNA- and cultivation-based tools in an effort to understand the drivers of microbial community structure (including radioactivity) and microbial interactions with select radionuclides and other factors across the range of habitats surveyed.

54 ENVIRONMENTAL SCIENCES↗

NASA NTRS1979

Programmable charge-coupled device /CCD/ correlator for pattern classification

The potential use of charge coupled device (CCD) programmable digital/analog correlators for multispectral data classification is discussed. CCD digital/analog correlator technology and the experimental evaluation of a 32-stage 4-bit test device are presented. The design of an IC for use in a multispectral classification system for 16 sensors and 8 bit accuracy is reviewed.

Mayer, D. J.↗

DOE OSTI2017

Counter Unmanned Aerial Systems Testing: Evaluation of VIS SWIR MWIR and LWIR passive imagers.

This report contains analysis of unmanned aerial systems as imaged by visible, short-wave infrared, mid-wave infrared, and long-wave infrared passive devices. Testing was conducted at the Nevada National Security Site (NNSS) during the week of August 15, 2016. Target images in all spectral bands are shown and contrast versus background is reported. Calculations are performed to determine estimated pixels-on-target for detection and assessment levels, and the number of pixels needed to cover a hemisphere for detection or assessment at defined distances. Background clutter challenges are qualitatively discussed for different spectral bands, and low contrast scenarios are highlighted for long-wave infrared imagers.

47 OTHER INSTRUMENTATION↗

NASA NTRS2019

Astrophysics and Technical Study of a Solar Neutrino Spacecraft: NIAC (NASA Innovative Advanced Concepts) Grant - NASA 2018-Phase-1

We report on our study of the design of a neutrino detector, shielding and veto array needed to operate a neutrino detector in space close to the Sun. This study also took into account the expected rates of Galactic gamma and cosmic rays in addition to the particles from the Sun.These preliminary studies show that we can devise a detector such that a small signal of neutrino interactions can be extracted from a large random number of events from the background sources using a double timing method from the conversion electron produced in the neutrino interaction and a secondary delayed signal from the nuclear excited state produced from the initial neutrino interaction; in our case the conversion of Ga 69 or 71 into Ge 69 or 71, but this method could apply to other nuclei with large neutrino cross sections such as Ir 115. Although these types of events need to be above 0.405 megaelectronvolt (MeV) neutrino energy and are only 66 percent of all conversion neutrino interactions on Gallium, this is a small price to pay for an increase of 10,000 by going close to the Sun to enhance the neutrino rate over the background combatorical fake-signal events. The conclusion of this Phase-1 study is very positive in that we can get the backgrounds less than 20 percent fake signals, and in addition to this we have devised another shielding method that makes the Galactic gamma-ray rate a hundred fold less which will make further improvements over these initial estimates. Although these studies are very encouraging it suggests that the next step is a NIAC Phase-II to actually build a test device,measuring basic principles such as light attention within the scintillator with high dopants and to take data in the lab with a cosmic-ray test stand and triggered X-ray source for comparison with simulated expected performance of the detector. This would be the perfect lead into a future proposal beyond a NIAC (NASA Innovative Advanced Concepts) Phase-II for a test flight of a small one-pint detector in orbit of the detector concept beyond Earth outside of the radiation belts.

Astrophysics↗