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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 37 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2016

Immunotoxicological and neurotoxicological profile of health effects following subacute exposure to geogenic dust from sand dunes at the Nellis Dunes Recreation Area, Las Vegas, NV

Exposure to geogenic particulate matter (PM) comprised of mineral particles has been linked to human health effects. However, very little data exist on health effects associated with geogenic dust exposure in natural settings. Therefore, we characterized particulate matter size, metal chemistry, and health effects of dust collected from the Nellis Dunes Recreation Area (NDRA), a popular off-road vehicle area located near Las Vegas, NV. Adult female B6C3F1 mice were exposed to several concentrations of mineral dust collected from active and vegetated sand dunes in NDRA. Dust samples (median diameter: 4.4 μm) were suspended in phosphate-buffered saline and delivered at concentrations ranging from 0.01 to 100 mg dust/kg body weight by oropharyngeal aspiration. ICP-MS analyses of total dissolution of the dust resulted in aluminum (55,090 μg/g), vanadium (70 μg/g), chromium (33 μg/g), manganese (511 μg/g), iron (21,600 μg/g), cobalt (9.4 μg/g), copper (69 μg/g), zinc (79 μg/g), arsenic (62 μg/g), strontium (620 μg/g), cesium (13 μg/g), lead 25 μg/g) and uranium (4.7 μg/g). Arsenic was present only as As(V). Mice received four exposures, once/week over 28-days to mimic a month of weekend exposures. Descriptive and functional assays to assess immunotoxicity and neurotoxicity were performed 24 h after the final exposure. The primary observation was that 0.1 to 100 mg/kg of this sand dune derived dust dose-responsively reduced antigen-specific IgM antibody responses, suggesting that dust from this area of NDRA may present a potential health risk. - Graphical abstract: During periods of heavy wind erosion, dense dust clouds of locally emitted geogenic dust enrobe the central Nellis Dune Recreation Area dunes. - Highlights: • Toxicological effects were characterized specific to geogenic dust exposure from a recreational sand dune site in Nevada. • The geogenic dust is a mixture of many metals and crystalline silica. • Exposure to geogenic dust dose-responsively decreased IgM antibody responses in a mouse model.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2014

Coherent manipulation of an NV center and one carbon nuclear spin

We study a three-qubit system formed by the NV center’s electronic and nuclear spin plus an adjacent spin 1/2 carbon {sup 13}C. Specifically, we propose a manipulation scheme utilizing the hyperfine coupling of the effective S=1 degree of freedom of the vacancy electrons to the two adjacent nuclear spins to achieve accurate coherent control of all three qubits.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2024

First-principles study of the Stark shift effect on the zero-phonon line of the NV center in diamond

Point defects in semiconductors are attractive candidates for quantum information science applications owing to their ability to act as spin-photon interface or single-photon emitters. However, the coupling between the change of dipole moment upon electronic excitation and stray electric fields in the vicinity of the defect, an effect known as Stark shift, can cause significant spectral diffusion in the emitted photons. In this work, using first principles computations, we revisit the methodology to compute the Stark shift of point defects up to the second order. The approach consists of applying an electric field on a defect in a slab and monitoring the changes in the computed zero-phonon line (i.e., difference in energy between the ground and excited state) obtained from constraining the orbital occupations (constrained-DFT). Here, we study the Stark shift of the negatively charged nitrogen-vacancy (NV) center in diamond using this slab approach. We discuss and compare two approaches to ensure a negatively charged defect in a slab and we show that converged values of the Stark shift measured by the change in dipole moment between the ground and excited states (Δ⁢μ) can be obtained. We obtain a Stark shift of Δ⁢μ = 2.68⁢D using the semilocal GGA-PBE functional and of Δ⁢μ = 2.23⁢D using the HSE hybrid functional. These values are in good agreement with experimental results. We also show that modern theory of polarization can be used on constrained-DFT to obtain Stark shifts in very good agreement with the slab computations.

36 MATERIALS SCIENCE↗
DOE OSTI2019

Creation of Localized NV Center Ensembles in CVD Diamond by Electron Beam Irradiation

Creation of localized NV center ensembles, produced by irradiation of CVD diamond with nitrogen doped delta-layer with 200 keV electron beam and the subsequent annealing is demonstrated. Results of optical measurements of activated areas at different irradiation doses are presented. Issues concerning defect formation in diamond lattice during the electron beam impact are discussed.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2021

Stewardship Considerations for Nevada FFACO Corrective Action Units Closed through the EM NV Soils Activity based on Monitoring of Radionuclide Transport

This report summarizes the EM NV/DRI work with the intent of conveying this information to the long-term land managers who will assume responsibility as EM NV completes its environmental restoration mission. A brief description of each of the six evaluated Soils Activity sites is provided, which is followed by a discussion of the findings regarding radionuclide transport learned at the sites. The implications of these findings are examined for site management, routine monitoring, and monitoring during potentially adverse events. Possible mitigation actions are also identified. The appendices provide a more detailed examination of the conditions under which radionuclide transport occurs at these sites.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Modeling Urban Acoustic Noise in the Las Vegas, NV Region

Ambient infrasound noise in quiet, rural environments has been extensively studied and well-characterized through noise models for several decades. More recently, creating noise models for high-noise rural environments has also become an area of active research. However, far less work has been done to create generalized low-frequency noise models for urban areas. The high ambient noise levels expected in cities and other highly populated areas means that these environments are regarded as poor locations for acoustic sensors, and historically, sensor deployment in urban areas were avoided for this reason. However, there are several advantages to placing sensors in urban environments, including convenience of deployment and maintenance, and increasingly, necessity, as more previously rural areas become populated. This study seeks to characterize trends in low-frequency urban noise by creating a background noise model for Las Vegas, NV, using the Las Vegas Infrasound Array (LVIA): a network of eleven infrasound sensors deployed throughout the city. Data included in this study spans from 2019 to 2021 and provides a largely uninterrupted record of noise levels in the city from 0.1–500 Hz, with only minor discontinuities on individual stations. We organize raw data from the LVIA sensors into hourly power spectral density (PSD) averages for each station and select from these PSDs to create frequency distributions for time periods of interest . These frequency distributions are converted into probability density functions (PDFs), which are then used to evaluate variations in frequency and amplitude over daily to seasonal timescale s. In addition to PDFs, the median, 5 th percentile, and 95 th percentile amplitude values are calculated across the entire frequency range. This methodology follows a well-established process for noise model creation.

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗
DOE OSTI2015

Great Basin NV Play Fairway Analysis - Carson Sink

All datasets and products specific to the Carson Sink Basin. Includes a packed ArcMap (.mpk), individually zipped shapefiles, and a file geodatabase for the Carson Sink area; a GeoSoft Oasis montaj project containing GM-SYS 2D gravity profiles along the trace of our seismic reflection lines; a 3D model in EarthVision; spreadsheet of links to published maps; and spreadsheets of well data.

15 GEOTHERMAL ENERGY↗
DOE OSTI2016

Health effects following subacute exposure to geogenic dusts from arsenic-rich sediment at the Nellis Dunes Recreation Area, Las Vegas, NV

Geogenic dust from arid environments is a possible inhalation hazard for humans, especially when using off-road vehicles that generate significant dust. This study focused on immunotoxicological and neurotoxicological effects following subacute exposure to geogenic dust generated from sediments in the Nellis Dunes Recreation Area near Las Vegas, Nevada that are particularly high in arsenic; the naturally-occurring arsenic concentrations in these surficial sediments ranged from 4.8 to 346 μg/g. Dust samples from sediments used in this study had a median diameter of 4.5 μm and also were a complex mixture of naturally-occurring metals, including aluminum, vanadium, chromium, manganese, iron, cobalt, copper, zinc, strontium, cesium, lead, uranium, and arsenic. Adult female B6C3F1 mice exposed via oropharyngeal aspiration to 0.01 to 100 mg dust/kg body weight, four times, a week apart, for 28 days, were evaluated 24 h after the last exposure. Peripheral eosinophils were increased at all concentrations, serum creatinine was dose responsively increased beginning at 1.0 mg/kg/day, and blood urea nitrogen was decreased at 10 and 100 mg/kg/day. Antigen-specific IgM responses and natural killer cell activity were dose-responsively suppressed at 0.1 mg/kg/day and above. Splenic CD4 + CD25 + T cells were decreased at 0.01, 0.1, 10, and 100 mg/kg/day. Antibodies against MBP, NF-68, and GFAP were selectively reduced. A no observed adverse effect level of 0.01 mg/kg/day and a lowest observed adverse effect level of 0.1 mg/kg/day were determined from IgM responses and natural killer cell activity, indicating that exposure to this dust, under conditions similar to our design, could affect these responses. - Highlights: • Toxicity of geogenic dust from arsenic-rich sediment in Nevada was characterized. • The geogenic dust is a mixture of many metals and crystalline silica. • Geogenic dust exposure decreased IgM antibodies and natural killer cell activity.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2026

Optical properties of a diamond NV color center from capped embedded multiconfigurational correlated wavefunction theory

Diamond defects are among the most promising qubits. Modeling their properties through accurate quantum mechanical simulations can further their development into robust units of information. We use the recently developed capped density functional embedding theory (capped-DFET) with the multiconfigurational n-electron valence second-order perturbation theory to characterize the electronic excitation energies for different spin manifolds of the well-characterized negatively charged substitutional N defect adjacent to a vacancy (V C ) in diamond (N C V C − ). We successfully reproduce vertical excitation energies for both triplet and singlet states of N C V C − with errors < 0.1 eV. Unlike other embedding methods, capped-DFET exhibits robust predictions that are approximately independent of the embedded cluster size: it only requires a cluster to contain the defect atoms and their nearest neighbors (as small as a 40-atom capped cluster). Furthermore, our method is free from slowly converging Coulomb interactions between charged defects, and thus also only weakly dependent on supercell size.

Chemistry↗
DOE OSTI2018

Spatially-resolved study of the Meissner effect in superconductors using NV-centers-in-diamond optical magnetometry

Non-invasive magnetic field sensing using optically-detected magnetic resonance of nitrogen-vacancy centers in diamond was used to study spatial distribution of the magnetic induction upon penetration and expulsion of weak magnetic fields in several representative superconductors. Vector magnetic fields were measured on the surface of conventional, elemental Pb and Nb, and compound LuNi 2 B 2 C and unconventional iron-based superconductors Ba 1-x K x Fe 2 As 2 (x = 0.34 optimal hole doping), Ba(Fe 1-x Co x )2As2 (x = 0.07 optimal electron doping), and stoichiometric CaKFe 4 As 4 , using variable-temperature confocal system with diffraction-limited spatial resolution. Magnetic induction profiles across the crystal edges were measured in zero-field-cooled and field-cooled conditions. While all superconductors show nearly perfect screening of magnetic fields applied after cooling to temperatures well below the superconducting transition, T c , a range of very different behaviors was observed for Meissner expulsion upon cooling in static magnetic field from above T c . Substantial conventional Meissner expulsion is found in LuNi 2 B 2 C, paramagnetic Meissner effect is found in Nb, and virtually no expulsion is observed in iron-based superconductors. In all cases, good correlation with macroscopic measurements of total magnetic moment is found.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗