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At least 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on SiO2 by Materials Project

SiO2 is quartz (alpha)-like structured and crystallizes in the tetragonal P4/mbm space group. The structure is three-dimensional. there are four inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is one shorter (1.62 Å) and three longer (1.64 Å) Si–O bond length. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is one shorter (1.62 Å) and three longer (1.63 Å) Si–O bond length. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is one shorter (1.62 Å) and three longer (1.63 Å) Si–O bond length. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is two shorter (1.61 Å) and two longer (1.63 Å) Si–O bond length. There are nine inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms. In the sixth O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the seventh O2- site, O2- is bonded in a linear geometry to two equivalent Si4+ atoms. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to two equivalent Si4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AlSi3O8 by Materials Project

AlSi3O8 is quartz (alpha)-derived structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with four SiO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.74–1.77 Å. There are three inequivalent Si sites. In the first Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra and corners with three SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.60–1.65 Å. In the second Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share corners with two equivalent AlO4 tetrahedra and corners with two SiO4 tetrahedra. There is one shorter (1.62 Å) and three longer (1.63 Å) Si–O bond length. In the third Si site, Si is bonded to four O atoms to form SiO4 tetrahedra that share a cornercorner with one AlO4 tetrahedra and corners with three SiO4 tetrahedra. There is one shorter (1.61 Å) and three longer (1.64 Å) Si–O bond length. There are eight inequivalent O sites. In the first O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the second O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the third O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the fourth O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the fifth O site, O is bonded in a bent 150 degrees geometry to two Si atoms. In the sixth O site, O is bonded in a bent 120 degrees geometry to one Al and one Si atom. In the seventh O site, O is bonded in a bent 150 degrees geometry to one Al and one Si atom. In the eighth O site, O is bonded in a bent 150 degrees geometry to two Si atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CeSe2 by Materials Project

CeSe2 is quartz (alpha)-like structured and crystallizes in the monoclinic Cc space group. The structure is three-dimensional. there are two inequivalent Ce4+ sites. In the first Ce4+ site, Ce4+ is bonded to four Se2- atoms to form corner-sharing CeSe4 tetrahedra. There are two shorter (2.72 Å) and two longer (2.73 Å) Ce–Se bond lengths. In the second Ce4+ site, Ce4+ is bonded to four Se2- atoms to form corner-sharing CeSe4 tetrahedra. There are two shorter (2.72 Å) and two longer (2.73 Å) Ce–Se bond lengths. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a bent 150 degrees geometry to two Ce4+ atoms. In the second Se2- site, Se2- is bonded in a bent 120 degrees geometry to two equivalent Ce4+ atoms. In the third Se2- site, Se2- is bonded in a bent 150 degrees geometry to two equivalent Ce4+ atoms. In the fourth Se2- site, Se2- is bonded in a bent 150 degrees geometry to two Ce4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Co2P2NO8 by Materials Project

(CoPO4)4N2 is quartz (alpha)-derived structured and crystallizes in the monoclinic C2/c space group. The structure is three-dimensional and consists of eight ammonia molecules and one CoPO4 framework. In the CoPO4 framework, there are two inequivalent Co+1.50+ sites. In the first Co+1.50+ site, Co+1.50+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with four PO4 tetrahedra. There are a spread of Co–O bond distances ranging from 1.84–1.87 Å. In the second Co+1.50+ site, Co+1.50+ is bonded to four O2- atoms to form CoO4 tetrahedra that share corners with four PO4 tetrahedra. There are a spread of Co–O bond distances ranging from 1.84–1.87 Å. There are two inequivalent P5+ sites. In the first P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four CoO4 tetrahedra. There is two shorter (1.54 Å) and two longer (1.55 Å) P–O bond length. In the second P5+ site, P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with four CoO4 tetrahedra. There are a spread of P–O bond distances ranging from 1.54–1.56 Å. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Co+1.50+ and one P5+ atom. In the second O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Co+1.50+ and one P5+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Co+1.50+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Co+1.50+ and one P5+ atom. In the fifth O2- site, O2- is bonded in a bent 150 degrees geometry to one Co+1.50+ and one P5+ atom. In the sixth O2- site, O2- is bonded in a bent 150 degrees geometry to one Co+1.50+ and one P5+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to one Co+1.50+ and one P5+ atom. In the eighth O2- site, O2- is bonded in a bent 150 degrees geometry to one Co+1.50+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CeSe2 by Materials Project

CeSe2 is quartz (beta)-like structured and crystallizes in the monoclinic C2/m space group. The structure is three-dimensional. there are three inequivalent Ce4+ sites. In the first Ce4+ site, Ce4+ is bonded to four Se2- atoms to form corner-sharing CeSe4 tetrahedra. There are three shorter (2.71 Å) and one longer (2.72 Å) Ce–Se bond lengths. In the second Ce4+ site, Ce4+ is bonded to four Se2- atoms to form corner-sharing CeSe4 tetrahedra. There are two shorter (2.71 Å) and two longer (2.72 Å) Ce–Se bond lengths. In the third Ce4+ site, Ce4+ is bonded to four Se2- atoms to form corner-sharing CeSe4 tetrahedra. There are one shorter (2.71 Å) and three longer (2.72 Å) Ce–Se bond lengths. There are eight inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a bent 150 degrees geometry to two Ce4+ atoms. In the second Se2- site, Se2- is bonded in a bent 150 degrees geometry to two equivalent Ce4+ atoms. In the third Se2- site, Se2- is bonded in a bent 150 degrees geometry to two Ce4+ atoms. In the fourth Se2- site, Se2- is bonded in a bent 150 degrees geometry to two Ce4+ atoms. In the fifth Se2- site, Se2- is bonded in a bent 150 degrees geometry to two equivalent Ce4+ atoms. In the sixth Se2- site, Se2- is bonded in a bent 150 degrees geometry to two equivalent Ce4+ atoms. In the seventh Se2- site, Se2- is bonded in a bent 150 degrees geometry to two equivalent Ce4+ atoms. In the eighth Se2- site, Se2- is bonded in a bent 150 degrees geometry to two Ce4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CeSe2 by Materials Project

CeSe2 is quartz (alpha)-like structured and crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Ce4+ sites. In the first Ce4+ site, Ce4+ is bonded to four Se2- atoms to form corner-sharing CeSe4 tetrahedra. There are a spread of Ce–Se bond distances ranging from 2.71–2.75 Å. In the second Ce4+ site, Ce4+ is bonded to four Se2- atoms to form corner-sharing CeSe4 tetrahedra. There are a spread of Ce–Se bond distances ranging from 2.72–2.74 Å. There are four inequivalent Se2- sites. In the first Se2- site, Se2- is bonded in a bent 150 degrees geometry to two Ce4+ atoms. In the second Se2- site, Se2- is bonded in a bent 150 degrees geometry to two Ce4+ atoms. In the third Se2- site, Se2- is bonded in a distorted bent 150 degrees geometry to two equivalent Ce4+ atoms. In the fourth Se2- site, Se2- is bonded in a bent 120 degrees geometry to two equivalent Ce4+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AlGa(PO4)2 by Materials Project

GaAl(PO4)2 is quartz (alpha)-derived structured and crystallizes in the monoclinic C2 space group. The structure is three-dimensional. Ga3+ is bonded to four O2- atoms to form GaO4 tetrahedra that share corners with four equivalent PO4 tetrahedra. All Ga–O bond lengths are 1.84 Å. Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four equivalent PO4 tetrahedra. All Al–O bond lengths are 1.75 Å. P5+ is bonded to four O2- atoms to form PO4 tetrahedra that share corners with two equivalent GaO4 tetrahedra and corners with two equivalent AlO4 tetrahedra. There is two shorter (1.54 Å) and two longer (1.55 Å) P–O bond length. There are four inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Ga3+ and one P5+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Al3+ and one P5+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to one Al3+ and one P5+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Ga3+ and one P5+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CrN2 by Materials Project

CrN2 is quartz (beta) structured and crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are three inequivalent Cr6+ sites. In the first Cr6+ site, Cr6+ is bonded to four N3- atoms to form corner-sharing CrN4 tetrahedra. There are a spread of Cr–N bond distances ranging from 1.69–1.79 Å. In the second Cr6+ site, Cr6+ is bonded to four N3- atoms to form corner-sharing CrN4 tetrahedra. There are a spread of Cr–N bond distances ranging from 1.68–1.79 Å. In the third Cr6+ site, Cr6+ is bonded to four N3- atoms to form corner-sharing CrN4 tetrahedra. There are a spread of Cr–N bond distances ranging from 1.68–1.78 Å. There are six inequivalent N3- sites. In the first N3- site, N3- is bonded in a bent 150 degrees geometry to two Cr6+ atoms. In the second N3- site, N3- is bonded in a bent 150 degrees geometry to two Cr6+ atoms. In the third N3- site, N3- is bonded in a bent 150 degrees geometry to two Cr6+ atoms. In the fourth N3- site, N3- is bonded in a bent 150 degrees geometry to two Cr6+ atoms. In the fifth N3- site, N3- is bonded in a bent 150 degrees geometry to two Cr6+ atoms. In the sixth N3- site, N3- is bonded in a bent 150 degrees geometry to two Cr6+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Al2Si3(NO5)2 by Materials Project

Al2Si3O10N2 is quartz (alpha)-derived structured and crystallizes in the orthorhombic Fdd2 space group. The structure is three-dimensional and consists of sixteen ammonia molecules and one Al2Si3O10 framework. In the Al2Si3O10 framework, Al3+ is bonded to four O2- atoms to form AlO4 tetrahedra that share corners with four SiO4 tetrahedra. There are a spread of Al–O bond distances ranging from 1.73–1.77 Å. There are two inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share corners with two equivalent AlO4 tetrahedra and corners with two equivalent SiO4 tetrahedra. All Si–O bond lengths are 1.63 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form SiO4 tetrahedra that share a cornercorner with one SiO4 tetrahedra and corners with three equivalent AlO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.61–1.64 Å. There are five inequivalent O2- sites. In the first O2- site, O2- is bonded in a bent 150 degrees geometry to one Al3+ and one Si4+ atom. In the second O2- site, O2- is bonded in a bent 150 degrees geometry to one Al3+ and one Si4+ atom. In the third O2- site, O2- is bonded in a bent 150 degrees geometry to two Si4+ atoms. In the fourth O2- site, O2- is bonded in a bent 150 degrees geometry to one Al3+ and one Si4+ atom. In the fifth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Al3+ and one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2025

Extinction Monitoring of Pulsed Proton Beams Using FPGA-Based Peak Detection

The Mu2e experiment at Fermilab imposes stringent requirements on the elimination of out-of-time beam in its pulsed proton beam - a requirement known as "extinction". We present a method to measure the out-of-time particle rates to calculate the level of extinction in the inter-pulse gaps. The proposed method utilizes an array of quartz Cherenkov radiators and photomultiplier tubes to detect particles scattered from a vacuum chamber in the M4 transfer beamline at Fermilab.The measurement will employ a new μTCA-based FPGA system for data acquisition and signal processing, utilizing real-time peak detection algorithms to count scattered beam particles. By integrating data over many transfers, the time profile of the out-of-time beam will be resolved to fractional levels relative to that of the in-time beam. These results are compared with G4beamline simulations to validate models of beam transport, dynamics, and extinction, providing critical input for optimizing beam delivery to Mu2e.

Hensley, Ryan [UC, Davis]↗
DOE OSTI2026

Calculating beam extinction in a pulsed proton beam using FPGA-based peak detection

The Mu2e experiment at Fermilab imposes stringent requirements on the elimination of out-of-time beam in its pulsed proton beam, a requirement known as “extinction”. Utilizing a new μTCA-based FPGA data acquisition system, we recorded live particle data from scattered particles incident on an array of quartz Cherenkov radiators and photomultiplier tubes to measure the extinction in the inter-pulse gaps in the pulsed proton beam. Minuscule errors in the derived signal period can make a measurement of the extinction impossible, so after taking a Fourier transform, further optimizations on the period were done based on the assumption that the signal period is stable over the full time of the beam spill while it is being resonantly extracted. After these optimizations, the beam extinction was shown to be on the level of 10^3.

Hensley, Ryan [UC, Davis]↗
DOE OSTI2022

Effects of Carbonic Acid-Rock Interactions on CO2/Brine Multiphase Flow Properties in the Upper Minnelusa Sandstones

Summary Carbon dioxide (CO2) injection into a deep saline aquifer can dissolve into formation brine and generate carbonic acid. The resulting acid can drive fluid-rock geochemical reactions. The impact of these fluid-rock geochemical reactions on porosity, permeability, and multiphase flow responses is relevant to the determination of CO2 storage capacity of deep saline aquifers. In this research, carbonic acid flooding experiments were performed on core samples consisting of poorly sorted, quartz-rich sand with laminated bedding from a possible CO2 storage target in northwest Wyoming. Complementary pre- and post-injection porosity and permeability, thin-section, Brunauer-Emmett-Teller (BET) surface area, mercury intrusion capillary pressure (MICP), and time-domain nuclear magnetic resonance (TD-NMR) measurements were conducted. Overall, both core porosity and permeability increased after a 7-day carbonic acid injection, from 6.2 to 8.4% and 1.6 to 3.7 md, respectively. We attributed these changes to carbonate mineral dissolution, which was evidenced by the effluent brine geochemistry, pore-throat size distribution (PTSD), and BET surface area. To be more specific, within the more-permeable section of core samples containing larger pore size, the permeability increment is apparent due to dolomite mineral grains and cements dissolution. However, for the lower-permeability section corresponding to the smaller pore size, mineral precipitation possibly lessened dissolution effects, leading to insignificant petrophysical properties changes. Consequently, the observed heterogeneous carbonic acid-rock interactions resulted in alterations of CO2/brine relative permeability (i.e., the initial CO2 saturation decreased and the CO2 flow capacity was enhanced). This research provides a fundamental understanding regarding effects of fluid-rock reactions on changes in static and multiphase flow properties of eolian sandstones, which lays the foundation for more accurate prediction/simulation of CO2 injection into deep saline aquifers.

Engineering↗
DOE OSTI2023

Gas-mediated trace element incorporation into rhyolite-hosted topaz: A synchrotron microbeam XAS study

Magmatic gas exsolving during late-stage cooling of shallow magmas has been considered an important facilitator of low-pressure alteration and metal transport. However, the chemical properties of such gas, particularly its metal transport mechanisms and capacity, remain elusive. Trace elements in minerals produced by gas-mediated surface reaction or precipitation from gas capture details of gas composition and reaction pathways. However, interpretation of mineral trace element contents is dependent on understanding crystallographic controls on gas/mineral partitioning. Here, this work investigates the structural accommodation of As, Mn, Ga, Ge, Fe, and Ti in vapor-deposited topaz of vesicular topaz rhyolite from the Thomas Range, Utah, through single-crystal synchrotron microbeam X-ray techniques on picogram quantities of those trace elements. X-ray absorption near edge structure (XANES) data indicates that these elements are incorporated into topaz as As 5+ , Fe 3+ , Mn 3+ , Ti 4+ , Ga 3+ , and Ge 4+ . Extended X-ray absorption fine structure (EXAFS) analysis for these trace elements, compared to EXAFS of structural Al and Si, reveals that As 5+ and Ge 4+ are incorporated directly into the tetrahedral site of the topaz structure, with the octahedral site accommodating Mn 3+ , Fe 3+ , Ga 3+ , and Ti 4+ . For As 5+ and Fe 3+ , the structural impact of substitution extends to at least second neighbors (other elements were only resolvable to first neighbors). Further interpretation of the EXAFS results suggests that the substitution of Ti 4+ results in increased distortion of the octahedral site, while the other trace elements induce more uniform expansion correlating in magnitude to their ionic radius. Comparison of quantified X-ray fluorescence (XRF) data for two topaz crystals from this rhyolite reveals variable trace element concentrations for As 5+ , Fe 3+ , Ga 3+ , and Ti 4+ , reflective of a source gas undersaturated in these trace elements changing in concentration over the period of topaz deposition. The identical Ge 4+ content of the two topaz crystals suggests that Ge 4+ in the gas was buffered by the growth of another Ge 4+ -bearing phase, such as quartz. The very low Mn 3+ content in the topaz crystals does not reflect the abundance of Mn 3+ in the gas (saturation of Mn is evidenced by coexisting bixbyite). Instead, it suggests a strong Jahn-Teller inhibitory effect to the substitution of Mn 3+ for Al 3+ in the distorted octahedral site of topaz. It is proposed that exsolution of an HF-enriched gas from cooling rhyolitic magma led to local scouring of Al, Si, and trace metals from the magma. Once topaz crystals nucleated, self-catalyzed reactions that recycle HF led to continued growth of topaz.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Sulfur speciation in dacitic melts using X-ray absorption near-edge structure spectroscopy of the S K -edge (S-XANES): Consideration of radiation-induced changes and the implications for sulfur in natural arc systems

Abstract The synchrotron technique of micro X-ray absorption near-edge structure spectroscopy at the sulfur K-edge (S-XANES) provides a unique opportunity to measure the proportion of different oxidation states of sulfur (S) in silicate glasses. Although applied extensively in the analysis of basaltic silicate glasses, few S-XANES studies have investigated variations in S oxidation states with fO2 in felsic silicate glasses. In addition, no study has systematically compared the S-XANES results obtained from the same samples at different photon flux densities to quantify the relationship between exposure time and changes in S speciation in silicate glass, as has been done for Fe and V. This study evaluates observed differences in S speciation measured in experimentally produced H2O-saturated dacitic glasses over a range of reducing to oxidizing conditions (from log fO2 = ΔFMQ-0.7 to ΔFMQ+3.3; FMQ is the fayalite-magnetite-quartz mineral redox buffer) and equilibrated at 1000 °C and 300 MPa. S-XANES spectra were collected at three different photon flux densities using three microspectroscopy beamlines. As is observed in S-XANES analyses of basaltic silicate glasses, beam-induced changes to the S6+/ΣS are observed as a function of photon flux density and beam exposure time. Our results demonstrate that silicate glasses of dacitic composition undergo beam-induced photo-reduction in samples equilibrated at ΔFMQ > +1.75 and photo-oxidation if equilibrated at ΔFMQ < +1. The time required to observe beam-induced changes in the spectra varies as a function of flux density, and our study establishes an upper photon density limit at ~1.0 × 1012 photons/µm2. The S6+/ΣS calculated from spectra collected below this absorbed photon limit at intermediate flux densities (~1–4 × 109 photons/s per µm2) are affected by beam damage, as no conditions were found to be completely free of beam-induced changes. However, the S6+/ΣS ratios calculated below the limit at intermediate flux densities are consistent with thermodynamic constraints, demonstrating that S6+/ΣS ratios calculated from S-XANES spectra can be considered reliable for estimating the oxygen fugacity. Our results carry important implications for the S budget of felsic magmas and dissolution mechanisms in evolved melts. While our results from all three flux densities show the presence of S4+ dissolved in relatively oxidized (ΔFMQ > +1.75) dacitic glass, even in the spectra exposed to the lowest photon densities, we are unable to rule out the possibility that the S4+ signal is the result of instantaneous X-ray irradiation induced beam damage using S-XANES alone. When our spectra are compared to S-XANES spectra from basaltic silicate glasses, important differences exist in the solubility of S2– and S6+ between dacitic silicate melts, pointing to differences in solubility mechanisms as melt composition changes. This study highlights the need for further investigation into beam damage systematics, presence of S4+, and the solubility mechanisms of different oxidation states of S as silicate melt composition changes.

Geochemistry & Geophysics↗
DOE OSTI2021

Mulan: a part-per-million measurement of the muon lifetime and determination of the Fermi constant

The part-per-million measurement of the positive muon lifetime and determination of the Fermi constant by the MuLan experiment at the Paul Scherrer Institute is reviewed. The experiment used an innovative, time-structured, surface muon beam and a near-4 \pi π , finely-segmented, plastic scintillator positron detector. Two in-vacuum muon stopping targets were used: a ferromagnetic foil with a large internal magnetic field, and a quartz crystal in a moderate external magnetic field. The experiment acquired a dataset of 1.6 \times 10^{12} 1.6 × 10 12 positive muon decays and obtained a muon lifetime \tau_{\mu} = 2\, 196\, 980.3(2.2) τ μ = 2 196 980.3 ( 2.2 ) ~ps (1.0~ppm) and Fermi constant G _F = 1.166\, 378\, 7(6) \times 10^{-5} F = 1.166 378 7 ( 6 ) × 10 − 5 GeV ^{-2} − 2 (0.5~ppm). The thirty-fold improvement in \tau_{\mu} τ μ has proven valuable for precision measurements in nuclear muon capture and the commensurate improvement in G _F F has proven valuable for precision tests of the standard model.

Carey, Rebecca↗
DOE OSTI2021

Evolution of Pore Structure and Permeability of Rocks Under Hydrothermal Conditions (Final Report)

The physical and transport properties of porous rocks can be altered by a variety of diagenetic, metamorphic, and tectonic processes, and the changes that result are of critical importance to such industrial applications as resource recovery, carbon dioxide sequestration, and waste isolation in geologic formations. The associated interrelationships between rocks, pore fluids and deformation are also key to understanding many natural processes, including dynamic metamorphism, fault mechanics, fault stability and pressure solution creep. In this project, we investigated the changes of permeability and pore geometry owing to inelastic deformation by solution-transfer, brittle fracturing and dislocation creep. In particular, we studied the coupling between pore fluids and deformation in fluid-filled quartz, calcite, mudstones and ultramafic rocks and examine the effects of coupled mechanical and chemical processes on the evolution of porosity and permeability under hydrothermal conditions. The investigations used a combination of techniques, that included triaxial laboratory experiments; uniaxial compressive loading with in situ observations of microstructure; permeability under hydrostatic compression; observations of microstructure using optical and electron microscopes, and micro-CT imaging; and numerical calculations. Laboratory experiments were designed to provide mechanical and transport data under conditions that isolate the particular mechanisms responsible for the changes. The data obtained were used to quantify changes in surface roughness, porosity, pore dimensions and their spatial fluctuations. The results of the experiments and data from image analyses were compared to the results of network, finite-difference and other numerical models to verify the validity of experimentally established relations between permeability and other rock properties. A bibliography for the period from 2015-2019 is appended below. New results obtained in the final year and the unfunded extension period are detailed below.

58 GEOSCIENCES↗
DOE OSTI2020

Niowave Power Converter Modeling and Testing

Niowave has designed, built and is now using in-beam a low power (up to 10 kW) lead bismuth eutectic (LBE) converter. In this concept, an electron beam is passed through a falling layer of LBE, converting the electron to neutrons which then pass into a vessel which is functionally a subcritical reactor configuration. A detailed report has been written by Niowave, entitled “LBE Neutron Converter Manual.” The LANL contribution has been modeling, followed by a flow visualization model made in quartz. The LANL contribution is reported herein.

43 PARTICLE ACCELERATORS↗
DOE OSTI2020

Hanford Double Shell Waste Tank Corrosion Studies (Final Report FY2019)

During fiscal year (FY) 2019, the Savannah River National Laboratory (SRNL) focused on four primary tasks for Hanford Double Shell Tanks (DSTs) corrosion studies. The first task, New Limits, was a continuation from the electrochemical work started in FY16, to expand electrochemical testing to elevated temperatures and elevated hydroxide concentrations and evaluate how these factors will influence pitting corrosion. Using the pitting factor (PF) equation, these new conditions were validated to provide a conservative estimate for the susceptibility of pitting corrosion on legacy carbon steel. The second task, Secondary Liner Corrosion, focused on Vapor Space Corrosion (VSC) and immersion testing studies using two commercially available vapor corrosion inhibitors (VCIs). For this FY, the VCI strategy was applied mid-experiment to determine performance on weathered coupons. The third task, Long-Term Open Circuit Potential (OCP) Drift, was performed using simplified simulated chemistries to evaluate change in pitting corrosion risk due to evolution of corrosion potential for mill-scale and freshly polished 600-grit surfaces. Finally, the fourth task, Microbiologically-Influenced Corrosion (MIC) studies, was focused on the study of leak detection pit (LDP) water sent from the Hanford tank farm for determination of bacteria that can be conducive to corrosion using commercially available kits: BART TM and MICkit® 5. In addition, this FY, a secondary task was added which was a continuation of the study of the Quartz-enhanced Photoacoustic Spectroscopy (QEPAS) system. Work was started but was ultimately not pursued. A summary of each task performed is presented below.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗