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At least 127 records · Page 7
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Pm3Pa by Materials Project

PaPm3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Pa is bonded to twelve Pm atoms to form PaPm12 cuboctahedra that share corners with four equivalent PaPm12 cuboctahedra, corners with eight equivalent PmPm8Pa4 cuboctahedra, edges with eight equivalent PaPm12 cuboctahedra, edges with sixteen equivalent PmPm8Pa4 cuboctahedra, faces with four equivalent PaPm12 cuboctahedra, and faces with fourteen PmPm8Pa4 cuboctahedra. There are four shorter (3.52 Å) and eight longer (3.55 Å) Pa–Pm bond lengths. There are two inequivalent Pm sites. In the first Pm site, Pm is bonded to four equivalent Pa and eight Pm atoms to form PmPm8Pa4 cuboctahedra that share corners with twelve equivalent PmPm8Pa4 cuboctahedra, edges with eight equivalent PaPm12 cuboctahedra, edges with sixteen PmPm8Pa4 cuboctahedra, faces with four equivalent PaPm12 cuboctahedra, and faces with fourteen PmPm8Pa4 cuboctahedra. There are four shorter (3.52 Å) and four longer (3.55 Å) Pm–Pm bond lengths. In the second Pm site, Pm is bonded to four equivalent Pa and eight equivalent Pm atoms to form distorted PmPm8Pa4 cuboctahedra that share corners with four equivalent PmPm8Pa4 cuboctahedra, corners with eight equivalent PaPm12 cuboctahedra, edges with twenty-four PmPm8Pa4 cuboctahedra, faces with six equivalent PaPm12 cuboctahedra, and faces with twelve PmPm8Pa4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pm3Er by Materials Project

ErPm3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Er is bonded to twelve Pm atoms to form ErPm12 cuboctahedra that share corners with four equivalent ErPm12 cuboctahedra, corners with eight equivalent PmPm8Er4 cuboctahedra, edges with eight equivalent ErPm12 cuboctahedra, edges with sixteen equivalent PmPm8Er4 cuboctahedra, faces with four equivalent ErPm12 cuboctahedra, and faces with fourteen PmPm8Er4 cuboctahedra. There are four shorter (3.61 Å) and eight longer (3.63 Å) Er–Pm bond lengths. There are two inequivalent Pm sites. In the first Pm site, Pm is bonded to four equivalent Er and eight Pm atoms to form PmPm8Er4 cuboctahedra that share corners with twelve equivalent PmPm8Er4 cuboctahedra, edges with eight equivalent ErPm12 cuboctahedra, edges with sixteen PmPm8Er4 cuboctahedra, faces with four equivalent ErPm12 cuboctahedra, and faces with fourteen PmPm8Er4 cuboctahedra. There are four shorter (3.61 Å) and four longer (3.63 Å) Pm–Pm bond lengths. In the second Pm site, Pm is bonded to four equivalent Er and eight equivalent Pm atoms to form PmPm8Er4 cuboctahedra that share corners with four equivalent PmPm8Er4 cuboctahedra, corners with eight equivalent ErPm12 cuboctahedra, edges with twenty-four PmPm8Er4 cuboctahedra, faces with six equivalent ErPm12 cuboctahedra, and faces with twelve PmPm8Er4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pm3Gd by Materials Project

GdPm3 is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Gd is bonded to twelve Pm atoms to form GdPm12 cuboctahedra that share corners with four equivalent GdPm12 cuboctahedra, corners with eight equivalent PmPm8Gd4 cuboctahedra, edges with eight equivalent GdPm12 cuboctahedra, edges with sixteen equivalent PmPm8Gd4 cuboctahedra, faces with four equivalent GdPm12 cuboctahedra, and faces with fourteen PmPm8Gd4 cuboctahedra. There are four shorter (3.64 Å) and eight longer (3.65 Å) Gd–Pm bond lengths. There are two inequivalent Pm sites. In the first Pm site, Pm is bonded to four equivalent Gd and eight Pm atoms to form PmPm8Gd4 cuboctahedra that share corners with twelve equivalent PmPm8Gd4 cuboctahedra, edges with eight equivalent GdPm12 cuboctahedra, edges with sixteen PmPm8Gd4 cuboctahedra, faces with four equivalent GdPm12 cuboctahedra, and faces with fourteen PmPm8Gd4 cuboctahedra. There are four shorter (3.64 Å) and four longer (3.65 Å) Pm–Pm bond lengths. In the second Pm site, Pm is bonded to four equivalent Gd and eight equivalent Pm atoms to form PmPm8Gd4 cuboctahedra that share corners with four equivalent PmPm8Gd4 cuboctahedra, corners with eight equivalent GdPm12 cuboctahedra, edges with twenty-four PmPm8Gd4 cuboctahedra, faces with six equivalent GdPm12 cuboctahedra, and faces with twelve PmPm8Gd4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on KPm3 by Materials Project

KPm3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. K is bonded to twelve Pm atoms to form KPm12 cuboctahedra that share corners with four equivalent KPm12 cuboctahedra, corners with eight equivalent PmK4Pm8 cuboctahedra, edges with eight equivalent KPm12 cuboctahedra, edges with sixteen equivalent PmK4Pm8 cuboctahedra, faces with four equivalent KPm12 cuboctahedra, and faces with fourteen PmK4Pm8 cuboctahedra. There are four shorter (3.72 Å) and eight longer (3.81 Å) K–Pm bond lengths. There are two inequivalent Pm sites. In the first Pm site, Pm is bonded to four equivalent K and eight Pm atoms to form PmK4Pm8 cuboctahedra that share corners with twelve equivalent PmK4Pm8 cuboctahedra, edges with eight equivalent KPm12 cuboctahedra, edges with sixteen PmK4Pm8 cuboctahedra, faces with four equivalent KPm12 cuboctahedra, and faces with fourteen PmK4Pm8 cuboctahedra. There are four shorter (3.72 Å) and four longer (3.81 Å) Pm–Pm bond lengths. In the second Pm site, Pm is bonded to four equivalent K and eight equivalent Pm atoms to form distorted PmK4Pm8 cuboctahedra that share corners with four equivalent PmK4Pm8 cuboctahedra, corners with eight equivalent KPm12 cuboctahedra, edges with twenty-four PmK4Pm8 cuboctahedra, faces with six equivalent KPm12 cuboctahedra, and faces with twelve PmK4Pm8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pm3Ho by Materials Project

HoPm3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ho is bonded to twelve Pm atoms to form HoPm12 cuboctahedra that share corners with four equivalent HoPm12 cuboctahedra, corners with eight equivalent PmPm8Ho4 cuboctahedra, edges with eight equivalent HoPm12 cuboctahedra, edges with sixteen equivalent PmPm8Ho4 cuboctahedra, faces with four equivalent HoPm12 cuboctahedra, and faces with fourteen PmPm8Ho4 cuboctahedra. There are four shorter (3.62 Å) and eight longer (3.63 Å) Ho–Pm bond lengths. There are two inequivalent Pm sites. In the first Pm site, Pm is bonded to four equivalent Ho and eight Pm atoms to form PmPm8Ho4 cuboctahedra that share corners with twelve equivalent PmPm8Ho4 cuboctahedra, edges with eight equivalent HoPm12 cuboctahedra, edges with sixteen PmPm8Ho4 cuboctahedra, faces with four equivalent HoPm12 cuboctahedra, and faces with fourteen PmPm8Ho4 cuboctahedra. There are four shorter (3.62 Å) and four longer (3.63 Å) Pm–Pm bond lengths. In the second Pm site, Pm is bonded to four equivalent Ho and eight equivalent Pm atoms to form PmPm8Ho4 cuboctahedra that share corners with four equivalent PmPm8Ho4 cuboctahedra, corners with eight equivalent HoPm12 cuboctahedra, edges with twenty-four PmPm8Ho4 cuboctahedra, faces with six equivalent HoPm12 cuboctahedra, and faces with twelve PmPm8Ho4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on BaPm3 by Materials Project

BaPm3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Ba is bonded to twelve Pm atoms to form BaPm12 cuboctahedra that share corners with four equivalent BaPm12 cuboctahedra, corners with eight equivalent PmBa4Pm8 cuboctahedra, edges with eight equivalent BaPm12 cuboctahedra, edges with sixteen equivalent PmBa4Pm8 cuboctahedra, faces with four equivalent BaPm12 cuboctahedra, and faces with fourteen PmBa4Pm8 cuboctahedra. There are eight shorter (3.77 Å) and four longer (3.83 Å) Ba–Pm bond lengths. There are two inequivalent Pm sites. In the first Pm site, Pm is bonded to four equivalent Ba and eight Pm atoms to form PmBa4Pm8 cuboctahedra that share corners with twelve equivalent PmBa4Pm8 cuboctahedra, edges with eight equivalent BaPm12 cuboctahedra, edges with sixteen PmBa4Pm8 cuboctahedra, faces with four equivalent BaPm12 cuboctahedra, and faces with fourteen PmBa4Pm8 cuboctahedra. There are four shorter (3.77 Å) and four longer (3.83 Å) Pm–Pm bond lengths. In the second Pm site, Pm is bonded to four equivalent Ba and eight equivalent Pm atoms to form PmBa4Pm8 cuboctahedra that share corners with four equivalent PmBa4Pm8 cuboctahedra, corners with eight equivalent BaPm12 cuboctahedra, edges with twenty-four PmBa4Pm8 cuboctahedra, faces with six equivalent BaPm12 cuboctahedra, and faces with twelve PmBa4Pm8 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pm3Sm by Materials Project

SmPm3 is alpha La-derived structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Sm is bonded to twelve Pm atoms to form SmPm12 cuboctahedra that share corners with four equivalent SmPm12 cuboctahedra, corners with eight equivalent PmPm8Sm4 cuboctahedra, edges with eight equivalent SmPm12 cuboctahedra, edges with sixteen equivalent PmPm8Sm4 cuboctahedra, faces with four equivalent SmPm12 cuboctahedra, and faces with fourteen PmPm8Sm4 cuboctahedra. All Sm–Pm bond lengths are 3.65 Å. There are two inequivalent Pm sites. In the first Pm site, Pm is bonded to four equivalent Sm and eight Pm atoms to form PmPm8Sm4 cuboctahedra that share corners with twelve equivalent PmPm8Sm4 cuboctahedra, edges with eight equivalent SmPm12 cuboctahedra, edges with sixteen PmPm8Sm4 cuboctahedra, faces with four equivalent SmPm12 cuboctahedra, and faces with fourteen PmPm8Sm4 cuboctahedra. All Pm–Pm bond lengths are 3.65 Å. In the second Pm site, Pm is bonded to four equivalent Sm and eight equivalent Pm atoms to form PmPm8Sm4 cuboctahedra that share corners with four equivalent PmPm8Sm4 cuboctahedra, corners with eight equivalent SmPm12 cuboctahedra, edges with twenty-four PmPm8Sm4 cuboctahedra, faces with six equivalent SmPm12 cuboctahedra, and faces with twelve PmPm8Sm4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pm3Tm by Materials Project

TmPm3 is beta Cu3Ti-like structured and crystallizes in the tetragonal I4/mmm space group. The structure is three-dimensional. Tm is bonded to twelve Pm atoms to form TmPm12 cuboctahedra that share corners with four equivalent TmPm12 cuboctahedra, corners with eight equivalent PmPm8Tm4 cuboctahedra, edges with eight equivalent TmPm12 cuboctahedra, edges with sixteen equivalent PmPm8Tm4 cuboctahedra, faces with four equivalent TmPm12 cuboctahedra, and faces with fourteen PmPm8Tm4 cuboctahedra. There are four shorter (3.61 Å) and eight longer (3.62 Å) Tm–Pm bond lengths. There are two inequivalent Pm sites. In the first Pm site, Pm is bonded to four equivalent Tm and eight Pm atoms to form PmPm8Tm4 cuboctahedra that share corners with twelve equivalent PmPm8Tm4 cuboctahedra, edges with eight equivalent TmPm12 cuboctahedra, edges with sixteen PmPm8Tm4 cuboctahedra, faces with four equivalent TmPm12 cuboctahedra, and faces with fourteen PmPm8Tm4 cuboctahedra. There are four shorter (3.61 Å) and four longer (3.62 Å) Pm–Pm bond lengths. In the second Pm site, Pm is bonded to four equivalent Tm and eight equivalent Pm atoms to form PmPm8Tm4 cuboctahedra that share corners with four equivalent PmPm8Tm4 cuboctahedra, corners with eight equivalent TmPm12 cuboctahedra, edges with twenty-four PmPm8Tm4 cuboctahedra, faces with six equivalent TmPm12 cuboctahedra, and faces with twelve PmPm8Tm4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Pm3Eu by Materials Project

EuPm3 is beta Cu3Ti-like structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. Eu is bonded to twelve Pm atoms to form EuPm12 cuboctahedra that share corners with six equivalent EuPm12 cuboctahedra, corners with twelve PmPm8Eu4 cuboctahedra, edges with eighteen PmPm8Eu4 cuboctahedra, faces with eight equivalent EuPm12 cuboctahedra, and faces with twelve PmPm8Eu4 cuboctahedra. All Eu–Pm bond lengths are 3.71 Å. There are two inequivalent Pm sites. In the first Pm site, Pm is bonded to four equivalent Eu and eight Pm atoms to form PmPm8Eu4 cuboctahedra that share corners with four equivalent EuPm12 cuboctahedra, corners with fourteen PmPm8Eu4 cuboctahedra, edges with six equivalent EuPm12 cuboctahedra, edges with twelve PmPm8Eu4 cuboctahedra, faces with four equivalent EuPm12 cuboctahedra, and faces with sixteen PmPm8Eu4 cuboctahedra. There are a spread of Pm–Pm bond distances ranging from 3.64–3.78 Å. In the second Pm site, Pm is bonded to four equivalent Eu and eight equivalent Pm atoms to form PmPm8Eu4 cuboctahedra that share corners with four equivalent EuPm12 cuboctahedra, corners with fourteen PmPm8Eu4 cuboctahedra, edges with six equivalent EuPm12 cuboctahedra, edges with twelve equivalent PmPm8Eu4 cuboctahedra, faces with four equivalent EuPm12 cuboctahedra, and faces with sixteen PmPm8Eu4 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Observationally constrained analysis on the distribution of fine- and coarse-mode nitrate in global models

Nitrate plays an important role in the Earth system and air quality. A key challenge in simulating the life cycle of nitrate aerosol in global models is to accurately represent mass size distribution of nitrate aerosol. In this study, we evaluate the performance of the Energy Exascale Earth System Model version 2 (E3SMv2) and the Community Earth System Model version 2 (CESM2), along with Aerosol Comparisons between Observations and Models (AeroCom) phase III models, in simulating spatial distribution of fine-mode nitrate, the mass size distribution of fine- and coarse-mode nitrate, and the gas–aerosol partitioning between nitric acid gas and nitrate, using long-term ground-based observations and measurements from multiple aircraft campaigns. We find that most models underestimate the annual mean PM 2.5 (particulate matter with diameter less than 2.5 µm) nitrate surface concentration averaged over all sites. The observed nitrate PM 2.5 / PM 10 and PM 1 / PM 4 ratios are influenced by the relative contribution of fine sulfate or organic particles and coarse dust or sea salt particles. Overall, the ground-based observations give an annual mean surface nitrate PM 2.5 / PM 10 ratio of 0.7. Most models underestimate the annual mean PM 2.5 / PM 10 ratio in all regions. There are large spreads in the modeled nitrate PM 1 / PM 4 ratios, which span the full range from 0 to 1. Most models underestimate the surface molar ratio of nitrate to total inorganic nitrate averaged across all sites. Our study indicates the importance of gas–aerosol partition parameterization and the simulation of dust and sea salt in correctly simulating the mass size distribution of nitrate.

Nitrate↗
DOE OSTI2023

Design and construction of the MUSE permanent magnet stellarator

This paper documents the design and construction of MUSE, the world's first permanent magnet (PM) stellarator and the first quasi-axisymmetric experiment. The purpose of MUSE is to develop and assess a new way of building optimised stellarators that uses simple planar coils PMs. Our PM optimisation algorithm consists of initialising a geometry to pack dipoles densely, running the FAMUS code to minimise surface field error subject to PM constraints and applying discrete jumps to reach a physically realisable solution. FAMUS treats the PM system as a set of ideal point dipoles. From there we construct finite-volume magnet towers to be housed in 3D-printed PM holders. We describe the design of the PM holders, which were validated by laser metrology. We analyse the effects of finite permeability, sensitivity to perturbations and magnetostatic forces. An exact analytic formula for the magnetic field from a finite-volume PM tower is presented to compute PM–PM forces and stress on the PM holder. Stellarator construction is complete and experiments are underway.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2022

Molecular speciation controls arsenic and lead bioaccessibility in fugitive dusts from sulfidic mine tailings

Communities nearby mine wastes in arid and semi-arid regions are potentially exposed to high concentrations of toxic metal(loid)s from fugitive dusts deriving from impoundments. To assess the relation between potentially lofted particles and human health risk, we studied the relationship between pharmacokinetic bioaccessibility and metal(loid) molecular speciation for mine tailings dust particulate matter (PM), with elevated levels of arsenic and lead (up to 59 and 34 mmol kg -1 , respectively), by coupling in vitro bioassay (IVBA) with X-ray absorption spectroscopy (XAS). Mine tailing efflorescent salts (PM ES ) and PM from the surface crust (0–1 cm, PM SC ) and near surface (0–25 cm) were isolated to <10 μm and <150 μm effective spherical diameter (PM 10 and PM 150 ) and reacted with synthetic gastric and lung fluid for 30 s to 100 h to investigate toxic metal(loid) release kinetics. Bioaccessible (BAc) fractions of arsenic and lead were about 10 and 100 times greater in gastric than in lung fluid simulant, respectively, and 10–100% of the maximum gastric BAc from PM 10 and PM 150 occurred within 30 s, with parabolic dissolution of fine, highly-reactive particles followed by slower release from less soluble sources. Evaporite salts were almost completely solubilized in gastric-fluid simulants. Arsenate within jarosite and sorbed to ferrihydrite, and lead from anglesite, were identified by XAS as the principal contaminant sources in the near surface tailings. In the synthetic lung fluid, arsenic was released continuously to 100 h, suggesting that residence time in vivo must be considered for risk determination. Analysis of pre- and post-IVBA PM indicated the release of arsenic in lung fluid was principally from arsenic-substituted jarosite, whereas in synthetic gastric fluid arsenic complexed on ferrihydrite surfaces was preferentially released and subsequently repartitioned to jarosite-like coordination at extended exposures. Lead dissolved at 30 s was subsequently repartitioned back to the solid phase as pyromorphite in phosphate rich lung fluid. The bioaccessibility of lead in surface tailings PM was limited due to robust sequestration in plumbojarosite. Kinetic release of toxic elements in both synthetic biofluids indicated that a single IVBA interval may not adequately describe release dynamics.

63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTAN↗
DOE OSTI2022

Impact of acute temperature and air pollution exposures on adult lung function: A panel study of asthmatics

Background Individuals with respiratory conditions, such as asthma, are particularly susceptible to adverse health effects associated with higher levels of ambient air pollution and temperature. This study evaluates whether hourly levels of fine particulate matter (PM 2.5 ) and dry bulb globe temperature (DBGT) are associated with the lung function of adult participants with asthma. Methods and findings Global positioning system (GPS) location, respiratory function (measured as forced expiratory volume at 1 second (FEV 1 )), and self-reports of asthma medication usage and symptoms were collected as part of the Exposure, Location, and Lung Function (ELF) study. Hourly ambient PM 2.5 and DBGT exposures were estimated by integrating air quality and temperature public records with time-activity patterns using GPS coordinates for each participant (n = 35). The relationships between acute PM 2.5 , DBGT, rescue bronchodilator use, and lung function collected in one week periods and over two seasons (summer/winter) were analyzed by multivariate regression, using different exposure time frames. In separate models, increasing levels in PM 2.5 , but not DBGT, were associated with rescue bronchodilator use. Conversely DBGT, but not PM 2.5 , had a significant association with FEV 1 . When DBGT and PM 2.5 exposures were placed in the same model, the strongest association between cumulative PM 2.5 exposures and the use of rescue bronchodilator was identified at the 0–24 hours (OR = 1.030; 95% CI = 1.012–1.049; p-value = 0.001) and 0–48 hours (OR = 1.030; 95% CI = 1.013–1.057; p-value = 0.001) prior to lung function measure. Conversely, DBGT exposure at 0 hours (β = 3.257; SE = 0.879; p-value>0.001) and 0–6 hours (β = 2.885; SE = 0.903; p-value = 0.001) hours before a reading were associated with FEV 1 . No significant interactions between DBGT and PM 2.5 were observed for rescue bronchodilator use or FEV 1 . Conclusions Short-term increases in PM 2.5 were associated with increased rescue bronchodilator use, while DBGT was associated with higher lung function (i.e. FEV 1 ). Further studies are needed to continue to elucidate the mechanisms of acute exposure to PM 2.5 and DBGT on lung function in asthmatics.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2026

Development of combined function dipole-quadrupole PMQs magnets for NSLS-II upgrade

This paper focuses on the R&D performed for the development of permanent magnets-based dipoles-quadrupoles combined function magnets (PMQs) for the future NSLSII upgrade “complex bend” lattice (CB). This new lattice uses PMQs that provide both bending (dipole) and strong focusing (quadrupole) magnetic field on the electron beam. The permanent magnet (PM) technology is suitable for the high magnetic field strengths (0.5 T, 130 T/m) required for such combine function magnets. PM technology leads to a compact magnet design that is essential in realizing the complex bend lattice concept, as well as a passive magnet solution which does not require electrical power supply reducing power consumption by ~ 80% (from 1.7 MW to 0.3 MW for NSLS-II). Two PMQs magnets designs are under consideration: A hybrid design that use both PM and soft iron poles, and Halbach type that is a pure PM design. Both PMQs designs present challenges in achieving the specified magnetic field quality due to their higher sensitivity to errors (mechanical tolerances and PM properties). This paper presents cost-effective designs and prototypes results for hybrid and Halbach PMQs, addressing various technical challenges while meeting the field requirements of the complex bend lattice for the NSLS-II upgrade.

N'gotta, Patrick [Brookhaven]↗
DOE OSTI2020

Pahute Mesa-Oasis Valley Hydrostratigraphic Framework Model for Corrective Action Units 101 and 102: Central and Western Pahute Mesa, Nye County, Nevada (Rev. 0)

A new, revised three-dimensional (3-D) hydrostratigraphic framework model (HFM) for the Central and Western Pahute Mesa Corrective Action Units 101 and 102 was completed in 2019. The initial (Phase I) model was completed in 2002 and was documented in A Hydrostratigraphic Model and Alternatives for the Groundwater Flow and Contaminant Transport Model of Corrective Action Units 101 and 102: Central and Western Pahute Mesa, Nye County, Nevada (BN, 2002). Subsequent flow and transport modeling revealed the need to collect additional data to reduce uncertainties. The Phase II data collection and characterization effort included extensive well drilling and testing activities, and rebuilding of the Phase I 3-D HFM, resulting in the Phase II HFM (NSTec, 2014). Further drilling (Well ER-20-12), data collection, and interpretive work (e.g., Thirsty Canyon Lineament [Wurtz and Day, 2018]) were incorporated into the Pahute Mesa-Oasis Valley (PM-OV) HFM. The PM-OV HFM incorporates the area of interest from the Phase II HFM and adds additional areas, primarily to the north and west with minor additions to the south and east. The new, expanded area matches the PM-OV groundwater basin as defined in Fenelon et al. (2016) and includes Pahute Mesa, a former nuclear testing area at the Nevada National Security Site; and Oasis Valley, a groundwater discharge area downgradient from contaminant source areas on Pahute Mesa. The data and information necessary to build the PM-OV HFM are provided in Navarro (2019). The PM-OV HFM will be used by hydrologic modelers who are tasked with developing a model to determine how contaminants are transported by groundwater flow in an area of complex geology. The model area is large (more than 6,250 square kilometers) and geologically complex, including Paleozoic- to Mesozoic-age structures (e.g., thrust faults, Thirsty Canyon Lineament), at least seven Tertiary-age calderas, several intrusive bodies, and many relatively recent basin-and-range normal faults. Investigators from the U.S. Geological Survey; National Security Technologies, LLC; National Laboratories; and U.S. Department of Energy contractors have organized the more than 300 volcanic units and other rocks in the model area into 77 hydrostratigraphic units (HSUs). The volcanic rocks are subdivided into 42 aquifers, 11 confining units, and 9 composite units (containing both aquifer and confining unit rocks). The underlying pre-Tertiary rocks were divided into 5 HSUs, comprising 2 aquifers and 3 confining units. The model also includes 1 alluvial aquifer unit, 8 intrusive confining units, and 1 granite confining unit. The model depicts the thickness, extent, and geometric relationships of these HSUs (“layers” in the model) along with all the major structural features that control them, including calderas and faults. The most substantive differences between the Phase II HFM and the PM-OVHFM include (1) addition of the new data and resulting revised interpretations from the additional area encompassed by the PM-OV groundwater basin; (2) incorporation of 16 new faults; (3) 12 boreholes from the northern extension; (4) 2 additional caldera-collapse collars; and (5) correlation of the simulated faulting and hydrostratigraphy in the eastern part of the model domain with the delineations represented in the neighboring Rainier Mesa-Shoshone Mountain HFM-Prime and Yucca Flat-Climax Mine HFM. All PM-OV HFM delineations were based on published and unpublished data from geophysical investigations, surface geologic maps, and drill-hole records. Phase II approached model uncertainty using the model-building software to test model configurations and hydrologic consequences using a range of values for parameters such as fault offset amounts and HSU elevations. The PM-OV HFM expands on this approach to encompass the entire PM-OV groundwater basin.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2020

Elevated-temperature cyclic properties of advanced manufactured materials

Microreactor developers at the 2019 GAIN Microreactors workshop expressed a need for advanced manufacturing to fabricate microreactor components. Powder metallurgy (PM) hot isostatic pressing (HIP) is more mature than other advanced manufacturing techniques for the following reasons: 1. a code case exists for Section III, Division 1, Subsection NB components of light water reactors to be manufactured using PM HIP Alloy 316L, and 2. tensile and creep properties have been shown to be equivalent to wrought material for Type 316 stainless steel and Grade 91. Thus, PM HIP is more readily deployable in the near term. Elevated-temperature cyclic properties of PM-HIP materials, however, have not been established. The scope of testing for Code qualification could be significantly reduced compared to a new material for the following reasons: 1. only a limited amount of time consuming creep testing would be required, and 2. testing of fatigue and creep-fatigue behavior could be reduced if it can be demonstrated that the properties are comparable to wrought material. The objective of this work package is to develop an understanding of the relationship of advanced materials processing on the material characteristics as they relate to elevated-temperature component design and construction. This will be achieved by the following: • Elevated-temperature fatigue and creep-fatigue testing of PM HIP and wrought Alloy 316L. • Fracture and microstructural characterization of the PM HIP and wrought Alloy 316L. • Analysis of the elevated-temperature fatigue and creep-fatigue properties of PM HIP Alloy 316L. • Draft a report evaluating the elevated-temperature fatigue and creep-fatigue properties of PM HIP Alloy 316L. • Pursue procurement of Alloy 316H and Grade 91 manufactured using PM HIP. • Initiate scoping studies of the procured Alloy 316H or Grade 91 manufactured using PM HIP contingent upon successful material procurement.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Influence of Fuel Properties on Gasoline Direct Injection Particulate Matter Emissions Over First 200 s of World-Harmonized Light-Duty Test Procedure Using an Engine Dynamometer and Novel “Virtual Drivetrain” Software

Abstract The influence of fuel properties on particulate matter (PM) emissions from a catalytic gasoline particulate filter (GPF) equipped gasoline direct injection (GDI) engine was investigated using novel “virtual drivetrain” software and an engine mated to an engine dynamometer. The virtual drivetrain software was developed in labview to operate the engine on an engine dynamometer as if it were in a vehicle undergoing a driving cycle. The software uses a physics-based approach to determine vehicle acceleration and speed based on engine load and a programed “shift” schedule to control engine speed. The software uses a control algorithm to modulate engine load and braking to match a calculated vehicle speed with the prescribed speed trace of the driving cycle of choice. The first 200 s of the World-harmonized Light-duty Test Procedure (WLTP) driving cycle was tested using six different fuel formulations of varying volatility, aromaticity, and ethanol concentration. The first 200 s of the WLTP was chosen as the test condition because it is the most problematic section of the driving cycle for controlling PM emissions due to the cold start and cold drive off. It was found that there was a strong correlation between aromaticity of the fuel and the engine-out PM emissions, with the highest emitting fuel producing more than double the mass emissions of the low PM production fuel. However, the post-GPF PM emissions depended greatly on the soot loading state of the GPF. The fuel with the highest engine-out PM emissions produced comparable post-GPF emissions to the lowest PM producing fuel over the driving cycle when the GPF was loaded over three cycles with the respective fuels. These results demonstrate the importance of GPF loading state when aftertreatment systems are used for PM reduction. It also shows that GPF control may be more important than fuel properties, and that regulatory compliance for PM can be achieved with proper GPF control calibration irrespective of fuel type.

Energy & Fuels↗
DOE OSTI2024

Air quality and health impacts of the 2020 wildfires in California

Abstract Background Wildfires in 2020 ravaged California to set the annual record of area burned to date. Clusters of wildfires in Northern California surrounded the Bay Area covering the skies with smoke and raising the air pollutant concentrations to hazardous levels. This study uses the Fire Inventory from the National Center for Atmospheric Research database and the Community Multiscale Air Quality model to estimate the effects of wildfire emissions on air quality during the period from August 16 to October 28 of 2020. In addition, low-cost sensor data for fine particulate matter (PM 2.5 ) from the PurpleAir network is used to enhance modeled PM 2.5 concentrations. The resulting impacts on ozone and PM 2.5 are used to quantify the health impacts caused by wildfires using the Benefits Mapping and Analysis Program – Community Edition. Results Wildfire activity significantly increased direct PM 2.5 emissions and emissions of PM 2.5 and ozone precursors. Direct PM 2.5 emissions surged up to 38 times compared to an average day. Modeling results indicated that wildfires alone led to a rise in ozone daily maximum 8-h average by up to 10 ppb and exceeded PM 2.5 air quality standards in numerous locations by up to 10 times. While modeled PM 2.5 concentrations were lower than measurements, correcting these with PurpleAir data improved the accuracy. The correction using PurpleAir data increased estimates of wildfire-induced mortality due to PM 2.5 exposure by up to 16%. Conclusions The increased hospital admissions and premature mortality attributed to wildfires were found to be comparable to the health impacts avoided by strategies aimed at meeting ozone and PM2.5 air quality standards. This suggests that widespread wildfire emissions can negate years of efforts dedicated to controlling air pollution. The integration of low-cost sensor data proved invaluable in refining the estimates of health impacts from PM2.5 resulting from wildfires.

54 ENVIRONMENTAL SCIENCES↗