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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,243 records · Page 69
All sourcesNASA NTRSDOE OSTI
NASA NTRS2014

Rapid Electrochemical Detection and Identification of Microbiological and Chemical Contaminants for Manned Spaceflight Project

Microbial control in the spacecraft environment is a daunting task, especially in the presence of human crew members. Currently, assessing the potential crew health risk associated with a microbial contamination event requires return of representative environmental samples that are analyzed in a ground-based laboratory. It is therefore not currently possible to quickly identify microbes during spaceflight. This project addresses the unmet need for spaceflight-compatible microbial identification technology. The electrochemical detection and identification platform is expected to provide a sensitive, specific, and rapid sample-to-answer capability for in-flight microbial monitoring that can distinguish between related microorganisms (pathogens and non-pathogens) as well as chemical contaminants. This will dramatically enhance our ability to monitor the spacecraft environment and the health risk to the crew. Further, the project is expected to eliminate the need for sample return while significantly reducing crew time required for detection of multiple targets. Initial work will focus on the optimization of bacterial detection and identification. The platform is designed to release nucleic acids (DNA and RNA) from microorganisms without the use of harmful chemicals. Bacterial DNA or RNA is captured by bacteria-specific probe molecules that are bound to a microelectrode, and that capture event can generate a small change in the electrical current (Lam, et al. 2012. Anal. Chem. 84(1): 21-5.). This current is measured, and a determination is made whether a given microbe is present in the sample analyzed. Chemical detection can be accomplished by directly applying a sample to the microelectrode and measuring the resulting current change. This rapid microbial and chemical detection device is designed to be a low-cost, low-power platform anticipated to be operated independently of an external power source, characteristics optimal for manned spaceflight and areas where power and computing resources are scarce.

Pierson, Duane↗
NASA NTRS2014

Native Fluorescence Detection Methods and Detectors for Naphthalene and/or Other Volatile Organic Compound Vapors

Naphthalene, benzene, toluene, xylene, and other volatile organic compounds have been identified as serious health hazards. This is especially true for personnel working with JP8 jet fuel and other fuels containing naphthalene as well as other hazardous volatile organic compounds (VOCs). Embodiments of the invention are directed to methods and apparatus for near-real-time in-situ detection and accumulated dose measurement of exposure to naphthalene vapor and other hazardous gaseous VOCs. The methods and apparatus employ excitation of fluorophors native or endogenous to compounds of interest using light sources emitting in the ultraviolet below 300 nm and measurement of native fluorescence emissions in distinct wavebands above the excitation wavelength. The apparatus of some embodiments are cell-phone-sized sensor/dosimeter "badges" to be worn by personnel potentially exposed to naphthalene or other hazardous VOCs. The badge sensor of some embodiments provides both real time detection and data logging of exposure to naphthalene or other VOCs of interest from which both instantaneous and accumulated dose can be determined. The badges employ a new native fluorescence based detection method to identify and differentiate VOCs. The particular focus of some embodiments are the detection and identification of naphthalene while other embodiments are directed to detection and identification of other VOCs like aromatic hydrocarbons such as benzene, toluene, and xylene.

Hug, William F.↗
NASA NTRS1984

Effect of a buried-wire gage on the separation bubble Numerical study

A numerically simulated buried-wire separation gage is investigated with emphasis on its effect on the separation bubble. The conjugated problem of a supersonic, time-dependent, two-dimensional flowfield above a conductive solid wall with an embedded heat source is solved using implicit finite difference algorithms. Steady-state and transient cases were computed for different locations of the heat source within the bubble. Results show that by using a steady heat source, the flow direction near the wall can be detected, without distorting the flowfield, only if the source is located in regions where the bubble is thick (i.e., not too close to the separation). The flow direction near separation can be detected by using a temperature pulse at the solid/fluid interface with insignificant distortion of the flowfield.

Degani, D.↗
DOE OSTI2020

Volume IV. The DUNE far detector single-phase technology

The preponderance of matter over antimatter in the early universe, the dynamics of the supernovae that produced the heavy elements necessary for life, and whether protons eventually decay -- these mysteries at the forefront of particle physics and astrophysics are key to understanding the early evolution of our universe, its current state, and its eventual fate. DUNE is an international world-class experiment dedicated to addressing these questions as it searches for leptonic charge-parity symmetry violation, stands ready to capture supernova neutrino bursts, and seeks to observe nucleon decay as a signature of a grand unified theory underlying the standard model. Central to achieving DUNE's physics program is a far detector that combines the many tens-of-kiloton fiducial mass necessary for rare event searches with sub-centimeter spatial resolution in its ability to image those events, allowing identification of the physics signatures among the numerous backgrounds. In the single-phase liquid argon time-projection chamber (LArTPC) technology, ionization charges drift horizontally in the liquid argon under the influence of an electric field towards a vertical anode, where they are read out with fine granularity. A photon detection system supplements the TPC, directly enhancing physics capabilities for all three DUNE physics drivers and opening up prospects for further physics explorations. The DUNE far detector technical design report (TDR) describes the DUNE physics program and the technical designs of the single- and dual-phase DUNE liquid argon TPC far detector modules. Volume IV presents an overview of the basic operating principles of a single-phase LArTPC, followed by a description of the DUNE implementation. Each of the subsystems is described in detail, connecting the high-level design requirements and decisions to the overriding physics goals of DUNE.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
NASA NTRS1997

Utility of BRDF Models for Estimating Optimal View Angles in Classification of Remotely Sensed Images

Statistical classification of remotely sensed images attempts to discriminate between surface cover types on the basis of the spectral response recorded by a sensor. It is well known that surfaces reflect incident radiation as a function of wavelength producing a spectral signature specific to the material under investigation. Multispectral and hyperspectral sensors sample the spectral response over tens and even hundreds of wavelength bands to capture the variation of spectral response with wavelength. Classification algorithms then exploit these differences in spectral response to distinguish between materials of interest. Sensors of this type, however, collect detailed spectral information from one direction (usually nadir); consequently, do not consider the directional nature of reflectance potentially detectable at different sensor view angles. Improvements in sensor technology have resulted in remote sensing platforms capable of detecting reflected energy across wavelengths (spectral signatures) and from multiple view angles (angular signatures) in the fore and aft directions. Sensors of this type include: the moderate resolution imaging spectroradiometer (MODIS), the multiangle imaging spectroradiometer (MISR), and the airborne solid-state array spectroradiometer (ASAS). A goal of this paper, then, is to explore the utility of Bidirectional Reflectance Distribution Function (BRDF) models in the selection of optimal view angles for the classification of remotely sensed images by employing a strategy of searching for the maximum difference between surface BRDFs. After a brief discussion of directional reflect ante in Section 2, attention is directed to the Beard-Maxwell BRDF model and its use in predicting the bidirectional reflectance of a surface. The selection of optimal viewing angles is addressed in Section 3, followed by conclusions and future work in Section 4.

Valdez, P. F.↗
DOE OSTI2024

Specialized protist communities on mycorrhizal fungal hyphae

Abstract Arbuscular mycorrhizal (AM) fungi not only play a crucial role in acquiring nutrients for plants but also serve as a habitat for soil microbes. Recent studies observed that AM fungal hyphae are colonized by specific bacterial communities. However, so far it has not been explored whether fungal hyphae and mycorrhizal networks also harbor specific communities of protists, a key group of microbes in the soil microbiome. Here, we characterized protist communities in soil in a compartment with plant roots and on hyphae collected from hyphal compartments without plant roots. We detected specific protist communities on fungal hyphae. Fourteen protistan amplicon sequences variants (ASVs) were significantly associated with fungal hyphae, half of which belonged to the Cercozoa group. This research, for the first-time detected specific protist ASVs directly associated with abundant AM fungus hyphae, highlighting the complexity of the hyphal food web.

Mycology↗
DOE OSTI2023

Online detection of airborne nanoparticle composition with mass spectrometry: Recent advances, challenges, and opportunities

Airborne nanoparticles are receiving growing attention due to their impacts on human health, air quality, and climate. Additionally, there are increasing applications of aerosol-based nanotechnology. Real-time measurement of airborne nanoparticle composition is challenging due to their small masses and the difficulties in effectively separating them from larger particles. Custom-built instruments based on mass spectrometry have been developed for nanoparticle composition, including thermal desorption-based, laser-based, and solution-based techniques. They have significantly promoted the understanding of airborne nanoparticles in the last two decades. However, they are affected by molecular fragmentation, lack of mass-resolving power, incomplete species detection, and difficulties in directly comparing to gas-phase measurements. Recent developments in atmospheric mass spectrometry provide possible solutions. Here, this review presents the potential application of these new advances to real-time measurements of the molecular nanoparticle composition and discusses the associated challenges. Such measurements present opportunities for a more comprehensive view of airborne nanoparticles and their impacts.

47 OTHER INSTRUMENTATION↗
DOE OSTI2021

Climatology and Evolution of the Antarctic Peninsula Föhn Wind-Induced Melt Regime From 1979–2018

Warm and dry föhn winds on the Antarctic Peninsula (AP) cause surface melt that can destabilize vulnerable ice shelves. Topographic funneling of these downslope winds through mountain passes and canyons can produce localized wind-induced melt that is difficult to quantify without direct measurements. Our Föhn Detection Algorithm (FöhnDA) identifies the surface föhn signature that causes melt from measurement by 12 Automatic Weather Stations on the AP, that train a machine learning model to detect föhn in 5 km Regional Atmospheric Climate Model 2 (RACMO2.3p2) simulations and in the ERA5 reanalysis model. We estimate the fraction of AP surface melt attributed to föhn and possibly katabatic winds and identify the drivers of melt, temporal variability, and long-term trends and evolution from 1979–2018. We find that föhn wind-induced melt accounts for 3.1% of the total melt on the AP and can be as high at 18% close to the mountains where the winds funnel through mountain canyons. Föhn-induced surface melt does not significantly increase from 1979–2018, despite a warmer atmosphere and more positive Southern Annular Mode. However, a significant increase (+0.1 Gt y-1) and subsequent decrease/stabilization occur in 1979–1998 and 1999–2018, consistent with the AP warming and cooling trends during the same time periods. Föhn occurrence, more than föhn strength, drives the annual variability in föhn-induced melt. Long-term föhn-induced melt trends and evolution are attributable to seasonal changes in föhn occurrence, with increased occurrence in summer, and decreased occurrence in fall, winter, and early spring over the past 20 years.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Integrating N -glycan and CODEX imaging reveal cell-specific protein glycosylation in healthy human lung

Identifying cell-specific glycan structures in human lungs is critical for understanding the chemistry and mechanisms that guide cell–cell and cell–matrix interactions and determining nuanced functions of specific glycosylation. Our dual-modality omics platform, which uses matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) to profile glycan chemistry at 50 μm × 50 μm scale, combined with co-detection by indexing (CODEX) to provide cell identification from the exact same tissue section, is a significant step in this direction. It enabled us to detect, differentiate, and reveal chemical properties of N-glycans in the various cell types of a human lung, suggesting the cell-specific function of distinct carbohydrate moieties. This innovative technological combination bridges the gap between the specific protein glycosylation and their cellular origin, paving the way for targeted studies in the lungs and many other human tissues where glycans mediate cell–cell recognition events.

Veličković, Dušan [Pacific Northwest National Labo↗
DOE OSTI2021

Use of nucleic acid amplification testing for rapid detection of Mycobacterium tuberculosis complex among U.S. tuberculosis patients from 2011–2017

Background: Nucleic acid amplification (NAA) tests rapidly detect Mycobacterium tuberculosis complex directly from clinical specimens, providing valuable results for those evaluated for tuberculosis. Methods: We analyzed characteristics of cases with NAA testing performed, compared cases with positive and negative NAA test results, and calculated turnaround time and time to treatment for all verified cases reported to the National Tuberculosis Surveillance System in the United States during 2011–2017. Results: Among 67082 verified tuberculosis cases with NAA testing information, 30820 (45.9%) were reported as not having an NAA test performed; the proportion without NAA testing declined annually, from 60.5% in 2011 to 33.6% in 2017. Of 67082 verified cases, 27912 (41.6%) had positive, 8215 (12.2%) had negative, and 135 (0.2%) had indeterminate NAA test results. Among the 33937 cases with an acid-fast bacilli (AFB) smear-positive result, 24093 (70.9%) had an NAA test performed; 11490 of the 30244 (38.0%) with an AFB smear-negative result had an NAA test performed. Although sputum was the most common specimen type tested, 79.8% (7023/8804) of nonsputum specimen types had a positive NAA test result. Overall, 63.7% of cases with laboratory testing had NAA test results reported <6 days following specimen collection; for 13891 cases not yet on treatment, median time to treatment after the laboratory report date was 2 days. Conclusions: Our analyses demonstrate increased NAA test utilization between 2011 and 2017. However, a large proportion of cases did not have an NAA test performed, reflecting challenges in broader uptake, suggesting an opportunity to expand use of this diagnostic methodology.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Prediction of spin polarized Fermi arcs in quasiparticle interference in CeBi

We predict that CeBi in the ferromagnetic state is a Weyl semimetal. Our calculations within density functional theory show the existence of two pairs of Weyl nodes on the momentum path (0,0,k z ) at 15meV above and 100meV below the Fermi level. Two corresponding Fermi arcs are obtained on surfaces of mirror-symmetric (010)-oriented slabs at E=15meV and both arcs are interrupted into three segments due to hybridization with a set of trivial surface bands. By studying the spin texture of surface states, we find the two Fermi arcs are strongly spin polarized but in opposite directions, which can be detected by spin-polarized ARPES measurements. Here, our theoretical study of quasiparticle interference (QPI) for a nonmagnetic impurity at the Bi site also reveals several features related to the Fermi arcs. Specifically, we predict that the spin polarization of the Fermi arcs leads to a bifurcation-shaped feature only in the spin-dependent QPI spectrum, serving as a fingerprint of the Weyl nodes.

36 MATERIALS SCIENCE↗
DOE OSTI2022

BICEP/ K e c k XIV: Improved constraints on axionlike polarization oscillations in the cosmic microwave background

We present an improved search for axionlike polarization oscillations in the cosmic microwave background (CMB) with observations from the Keck Array . An all-sky, temporally sinusoidal rotation of CMB polarization, equivalent to a time-variable cosmic birefringence, is an observable manifestation of a local axion field and potentially allows a CMB polarimeter to detect axionlike dark matter directly. We describe improvements to the method presented in previous work, and we demonstrate the updated method with an expanded dataset consisting of the 2012–2015 observing seasons. We set limits on the axion-photon coupling constant for mass m in the range 10 - 23 – 10 - 18 eV , which corresponds to oscillation periods on the order of hours to years. Our results are consistent with the background model. For periods between 1 and 30 d ( 1.6 × 10 - 21 ≤ m ≤ 4.8 × 10 - 20 eV ), the 95%-confidence upper limits on rotation amplitude are approximately constant with a median of 0.27°, which constrains the axion-photon coupling constant to g φ γ < ( 4.5 × 10 - 12 GeV - 1 ) m / ( 10 - 21 eV ) , if axionlike particles constitute all of the dark matter. More than half of the collected BICEP dataset has yet to be analyzed, and several current and future CMB polarimetry experiments can apply the methods presented here to achieve comparable or superior constraints. In the coming years, oscillation measurements can achieve the sensitivity to rule out unexplored regions of the axion parameter space.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

Termination switching of antiferromagnetic proximity effect in topological insulator

This work reports the ferromagnetism of topological insulator, (Bi,Sb) 2 Te 3 (BST), with a Curie temperature of approximately 120 K induced by magnetic proximity effect (MPE) of an antiferromagnetic CrSe. The MPE was shown to be highly dependent on the stacking order of the heterostructure, as well as the interface symmetry: Growing CrSe on top of BST results in induced ferromagnetism, while growing BST on CrSe yielded no evidence of an MPE. Cr-termination in the former case leads to double-exchange interactions between Cr 3+ surface states and Cr 2+ bulk states. This Cr 3+ -Cr 2+ exchange stabilizes the ferromagnetic order localized at the interface and magnetically polarizes the BST Sb band. In contrast, Se-termination at the CrSe/BST interface yields no detectable MPE. These results directly confirm the MPE in BST films and provide critical insights into the sensitivity of the surface state.

42 ENGINEERING↗
DOE OSTI2025

Higgs-portal dark matter in Brane-world cosmology

Abstract The Higgs-portal scalar dark matter (DM) model is a simple extension of the Standard Model (SM) to incorporate a DM particle to the SM, where a $$Z_2$$ Z 2 -odd real scalar field is introduced as a DM candidate. We consider this DM model in the context of 5-dimensional brane-world cosmology, where our 3-dimensional space is realized as a hyper-surface embedded in 4-dimensional space. In the setup, all the SM and DM fields reside on the hyper-surface while graviton lives in the bulk. We consider two well-known brane-world cosmologies, namely, the Randall–Sundrum (RS) and the Gauss–Bonnet (GB) brane-world cosmologies, in which the standard Big Bang cosmology is reproduced at low temperatures below the so-called “transition temperature” while at high temperatures the expansion law of the universe is significantly modified. Such a non-standard expansion law directly impacts the prediction for the relic density of the Higgs-portal DM. We investigate the brane-world cosmological effects and identify the allowed model parameter region by combining the constraints from the observed DM relic density, and the direct and indirect DM detection experiments. It is well-known that only DM masses in the vicinity of half the Higgs boson mass are allowed in the Higgs-portal scalar DM model. We find that the allowed parameter region becomes more severely constrained and even disappears in the RS cosmology, while the GB cosmological effect significantly enlarges the allowed region. Upon discovering Higgs-portal DM, we can determine transition temperature in the GB brane-world cosmology.

Liu, Taoli↗
DOE OSTI2020

Noncontact Flow Rate Using Laser Ultrasonics

Several types of advanced nuclear reactors are cooled with high-temperature liquid metal or molten salt flows. There is a critical need to measure flow velocity in flow channels for test purposes, and eventually in operational reactors. In conventional ultrasonic flow sensors, ultrasonic waves traveling in both the upstream and downstream directions are generated and detected by transducers that must contact the flow channels. A shift in the frequency or transit time between the two ultrasonic waves is measured to determine flow velocity. We describe here an initial effort to apply that sensing concept when the contact transducers are replaced by laser-based generation and detection instrumentation. This noncontact sensing avoids many practical problems associated with contact transducers when implemented on flow channels at high temperature. Laser-based flow monitoring can also be applied to hot-process piping in the geothermal energy, chemical-processing and petroleum-refining industries. Our effort has included theoretical simulation of noncontact laser-based flow monitoring, indicating capability of measuring flow velocities relevant to reactor cooling. It also included a room-temperature experimental demonstration using water as the flow liquid, and indicating capability of measuring flow velocity at a responsivity roughly consistent with simulation predictions. Plans were made for an experimental demonstration at Oregon State University using liquid metal at 110 degrees C.

02 PETROLEUM↗
DOE OSTI2021

Mid-infrared Pulsed Upconversion Imaging in a Rotating Detonation Combustor

To meet the challenges associated with performing mid-InfraRed (IR) imaging in Rotating Detonation Combustors (RDCs), a novel pulsed mid-IR UpConversion Imaging (UCI) diagnostic has been implemented. UCI is an alternative to direct mid-IR detection that uses nonlinear optical frequency mixing to shift mid-IR wavelengths carrying a target image to shorter wavelengths that can be imaged with high-performance silicon-based CCD/CMOS cameras. This approach offers several favorable properties including high spectral selectivity, high temporal resolution, and superior low-light detectivity. A hydrogen-air research RDC was operated with carbon dioxide addition to allow pulsed UCI imaging of mid-IR luminosity within the combustion channel from spontaneous thermal emissions. The resulting measurements demonstrate high spatiotemporal resolution capable of imaging small structures near the supersonically propagating detonation wave front. The results show how this technique can be used to observe sharp gradients and millimeter-scale structures in the high-temperature, high-pressure zones RDC flow fields.

White, Logan W.↗
DOE OSTI2022

The Solvation of the E. coli CheY Phosphorylation Site Mapped by XFMS

The Escherichia coli CheY protein belongs to a large bacterial response regulator superfamily. X-ray hydroxy radical foot-printing with mass spectroscopy (XFMS) has shown that allosteric activation of CheY by its motor target triggers a concerted internalization of aromatic sidechains. We reanalyzed the XFMS data to compare polar versus non-polar CheY residue positions. The polar residues around and including the 57D phosphorylated site had an elevated hydroxy radical reactivity. Bioinformatic measures revealed that a water-mediated hydrogen bond network connected this ring of residues with the central 57D. These residues solvated 57D to energetically stabilize the apo-CheY fold. The abundance of these reactive residues was reduced upon activation. This result was supported by the bioinformatics and consistent with the previously reported activation-induced increase in core hydrophobicity. It further illustrated XFMS detection of structural waters. Direct contacts between the ring residues and the phosphorylation site would stabilize the aspartyl phosphate. In addition, we report that the ring residue, 18R, is a constant central node in the 57D solvation network and that 18R non-polar substitutions determine CheY diversity as assessed by its evolutionary trace in bacteria with well-studied chemotaxis. These results showcase the importance of structured water dynamics for phosphorylation-mediated signal transduction.

59 BASIC BIOLOGICAL SCIENCES↗
NASA NTRS1972

A technique for position sensing and improved momentum evaluation of microparticle impacts in space.

The design of a three element piezoelectric microparticle impact sensing diaphragm is described which is sensitive to the detection of momentum propagated by the bending wave. The design achieves a sensitivity of .03 microdyn/sec and optimizes the detection of the direct-path pulse from impact relative to secondary reflections and interference from discontinuities. Measurement of the relative arrival times and the maximum amplitudes of the outputs from the three piezoelectric sensors leads to the determination of the impact position and the normally resolved impact momentum exchange. Coincidence of the signals and a partial redundancy of data leads to a very high noise discrimination.

Mcdonnell, J. A. M.↗