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At least 19 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on AgO by Materials Project

AgO crystallizes in the tetragonal I4_1/a space group. The structure is three-dimensional. there are two inequivalent Ag2+ sites. In the first Ag2+ site, Ag2+ is bonded in a distorted linear geometry to six equivalent O2- atoms. There are a spread of Ag–O bond distances ranging from 2.15–2.96 Å. In the second Ag2+ site, Ag2+ is bonded in a distorted square co-planar geometry to four equivalent O2- atoms. All Ag–O bond lengths are 2.08 Å. O2- is bonded in a distorted trigonal non-coplanar geometry to five Ag2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AgO by Materials Project

AgO crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ag2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. There are two shorter (2.16 Å) and two longer (2.17 Å) Ag–O bond lengths. O2- is bonded to four equivalent Ag2+ atoms to form a mixture of edge and corner-sharing OAg4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Si(AgO)4 by Materials Project

Si(AgO)4 crystallizes in the tetragonal P4_2/n space group. The structure is three-dimensional. Ag1+ is bonded in a distorted T-shaped geometry to three equivalent O2- atoms. There are a spread of Ag–O bond distances ranging from 2.15–2.65 Å. Si4+ is bonded in a tetrahedral geometry to four equivalent O2- atoms. All Si–O bond lengths are 1.66 Å. O2- is bonded in a 4-coordinate geometry to three equivalent Ag1+ and one Si4+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AgO by Materials Project

AgO is Zincblende, Sphalerite structured and crystallizes in the cubic F-43m space group. The structure is three-dimensional. Ag2+ is bonded to four equivalent O2- atoms to form corner-sharing AgO4 tetrahedra. All Ag–O bond lengths are 2.19 Å. O2- is bonded to four equivalent Ag2+ atoms to form corner-sharing OAg4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AgO by Materials Project

AgO crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are two inequivalent Ag2+ sites. In the first Ag2+ site, Ag2+ is bonded in a distorted linear geometry to two equivalent O2- atoms. Both Ag–O bond lengths are 2.14 Å. In the second Ag2+ site, Ag2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. There are two shorter (2.07 Å) and two longer (2.08 Å) Ag–O bond lengths. O2- is bonded in a distorted trigonal non-coplanar geometry to three Ag2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cu(AgO)2 by Materials Project

Cu(AgO)2 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Ag1+ is bonded in a linear geometry to two O2- atoms. There are one shorter (2.13 Å) and one longer (2.14 Å) Ag–O bond lengths. Cu2+ is bonded in a square co-planar geometry to four O2- atoms. There are two shorter (2.02 Å) and two longer (2.03 Å) Cu–O bond lengths. There are two inequivalent O2- sites. In the first O2- site, O2- is bonded in a square co-planar geometry to two equivalent Ag1+ and two equivalent Cu2+ atoms. In the second O2- site, O2- is bonded in a square co-planar geometry to two equivalent Ag1+ and two equivalent Cu2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Ba(AgO)2 by Materials Project

Ba(AgO)2 crystallizes in the tetragonal I4_1/amd space group. The structure is three-dimensional. Ba2+ is bonded to six equivalent O2- atoms to form a mixture of edge and corner-sharing BaO6 octahedra. The corner-sharing octahedral tilt angles are 4°. There are two shorter (2.62 Å) and four longer (3.00 Å) Ba–O bond lengths. Ag1+ is bonded in a linear geometry to two equivalent O2- atoms. Both Ag–O bond lengths are 2.10 Å. O2- is bonded to three equivalent Ba2+ and two equivalent Ag1+ atoms to form a mixture of distorted edge and corner-sharing OBa3Ag2 trigonal bipyramids.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on AgO by Materials Project

AgO crystallizes in the monoclinic C2/c space group. The structure is three-dimensional. Ag2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. There are two shorter (2.16 Å) and two longer (2.18 Å) Ag–O bond lengths. O2- is bonded to four equivalent Ag2+ atoms to form a mixture of edge and corner-sharing OAg4 tetrahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cu(AgO)2 by Materials Project

Cu(AgO)2 crystallizes in the orthorhombic Immm space group. The structure is three-dimensional. Ag1+ is bonded in a 4-coordinate geometry to four equivalent O2- atoms. There are two shorter (2.27 Å) and two longer (2.66 Å) Ag–O bond lengths. Cu2+ is bonded in a square co-planar geometry to four equivalent O2- atoms. All Cu–O bond lengths are 1.97 Å. O2- is bonded to four equivalent Ag1+ and two equivalent Cu2+ atoms to form a mixture of distorted corner and edge-sharing OCu2Ag4 octahedra. The corner-sharing octahedra tilt angles range from 0–10°.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Dynamics of the abrupt change in Pacific Plate motion around 50 million years ago

Changes in Pacific Plate motion combined near equally with hotspot drift to generate the prominent bend in the Hawaiian-Emperor seamount chain some 50 million years ago, according to kinematic plate reconstruction and global dynamic models. A drastic change in plate tectonics and mantle convection occurred around 50 Ma as exemplified by the prominent Hawaiian-Emperor Bend. Both an abrupt Pacific Plate motion change and a change in mantle plume dynamics have been proposed to account for the Hawaiian-Emperor Bend, but debates surround the relative contribution of the two mechanisms. Here we build kinematic plate reconstructions and high-resolution global dynamic models to quantify the amount of Pacific Plate motion change. We find Izanagi Plate subduction, followed by demise of the Izanagi-Pacific Ridge and Izu-Bonin-Mariana subduction initiation alone, is incapable of causing a sudden change in plate motion, challenging the conventional hypothesis on the mechanisms of Pacific Plate motion change. Instead, Palaeocene slab pull from Kronotsky intraoceanic subduction in the northern Pacific exerts a northward pull on the Pacific Plate, while its Eocene demise leads to a sudden 30-35 degrees change in plate motion, accounting for about half of the Hawaiian-Emperor Bend. We suggest the Pacific Plate motion change and hotspot drift due to plume dynamics could have contributed nearly equally to the formation of the Hawaiian-Emperor Bend. Such a scenario is consistent with available constraints from global plate circuits, palaeomagnetic data and geodynamic models.

Hu, Jiashun↗
DOE OSTI2020

The Road to Trinity: Seventy-five years ago, Los Alamos scientists detonated the world’s first nuclear explosion

With a brilliant hot flash and a loud boom, the giant mushroom cloud with its fiery core filled the predawn sky above the New Mexico desert. The nuclear age had begun. It was 75 years ago on July 16, 1945, that Los Alamos scientists changed the world with the successful detonation of “the Gadget” – the device created to test the Fat Man implosion-type plutonium weapon before it was taken into combat. However, the road to Trinity, as the test was named by J. Robert Oppenheimer, who is thought to have been inspired by a line in a John Donne poem, was a difficult one.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2021

First atomic weapons following WWII were detonated 75 years ago Operation Crossroads kicks off era of testing Los Alamos-created weapons [Slides]

It was time to test. After the Los Alamos-created atomic bombs helped end World War II, the no-longer-secret Lab transitioned into an era of weapons testing, starting 75 years ago with Operation Crossroads with the goal of studying nuclear weapons’ effects on warships. In August 1945, U.S. Senator Brien McMahon, who later authored the Atomic Energy Act of 1946, said: “In order to test the destructive powers of the atomic bomb against naval vessels, I would like to see these (Japanese naval) ships taken to sea and an atomic bomb dropped on them. The resulting explosion should prove to us just how effective the atomic bomb is when used against the giant naval ships.”

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗
DOE OSTI2020

Materials Data on Ni(AgO)2 by Materials Project

Ag2NiO2 is Calaverite-derived structured and crystallizes in the trigonal R-3m space group. The structure is two-dimensional and consists of three Ag2NiO2 sheets oriented in the (0, 0, 1) direction. Ni2+ is bonded to six equivalent O2- atoms to form edge-sharing NiO6 octahedra. All Ni–O bond lengths are 2.06 Å. Ag1+ is bonded in a 3-coordinate geometry to three equivalent O2- atoms. All Ag–O bond lengths are 2.42 Å. O2- is bonded to three equivalent Ni2+ and three equivalent Ag1+ atoms to form a mixture of edge and corner-sharing ONi3Ag3 octahedra. The corner-sharing octahedral tilt angles are 0°.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Neutralizing Antibodies to SARS-CoV-2 Selected from a Human Antibody Library Constructed Decades Ago

Combinatorial antibody libraries not only effectively reduce antibody discovery to a numbers game, but enable documentation of the history of antibody responses in an individual. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has prompted a wider application of this technology to meet the public health challenge of pandemic threats in the modern era. Herein, a combinatorial human antibody library constructed 20 years before the coronavirus disease 2019 (COVID-19) pandemic is used to discover three highly potent antibodies that selectively bind SARS-CoV-2 spike protein and neutralize authentic SARS-CoV-2 virus. Compared to neutralizing antibodies from COVID-19 patients with generally low somatic hypermutation (SHM), these three antibodies contain over 13–22 SHMs, many of which are involved in specific interactions in their crystal structures with SARS-CoV-2 spike receptor binding domain. The identification of these somatically mutated antibodies in a pre-pandemic library raises intriguing questions about the origin and evolution of these antibodies with respect to their reactivity with SARS-CoV-2.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2025

Effect of seasonal anoxia on geochemical cycling in a stratified pond: Comparison to cooler pond conditions 40 years ago

Seasonal stratification in temperate lakes deeper than a few meters creates favorable conditions for pronounced vertical redox zones, often resulting in anaerobic hypolimnions and significant geochemical changes. Here, this study examined thermocline formation and trace element behavior in a seasonally stratified pond amid rising air temperatures. Over two years, data were collected from Pond B at the US Department of Energy Savannah River Site in Aiken, South Carolina. Pond B, a man-made monomictic reservoir, received cooling water from a nuclear reactor from 1961 to 1964. Strong thermal stratification forms a distinct thermocline in May and progresses downward until November. Compared to the 1980s, this study shows a delayed onset and extended duration of stratification. The prolonged summer stratification reduces deep water oxygen replenishment, extending hypoxic conditions. Trace and major elements sampled in the water column revealed strong correlations between As, Fe, and Mn profiles, with concentrations increasing by 1–2 orders of magnitude in the anaerobic hypolimnion. This period captured the seasonal transition from winter mixing to summer stratification to fall overturn. Under anoxic conditions, Fe(III) reduces to Fe(II) in the sediment, releasing dissolved iron into the water column. The extended anoxic periods likely promoted arsenic release from sediments. Prolonged anoxia may enhance arsenic mobilization and solubility in the lake. This study illustrates how climate-induced changes in seasonal stratification of contaminated waters can convert contaminant sinks into sources, offering insights into the cycling of arsenic and other dissolved ions in stratified lakes and their implications for water quality management.

Anoxic conditions↗
DOE OSTI2024

Stellar populations and merger rates of brightest cluster galaxies a billion years ago: SDSS MaNGA IFU spectroscopy

ABSTRACT We investigate the spectroscopic properties of 85 brightest cluster galaxies (BCGs) and their companions observed with the SDSS MaNGA integral field unit. Galaxy redshifts are between 0.08 < z < 0.15, allowing for a field-of-view up to 80 × 80 kpc. For the main galaxies: the average age of the BCG cores is 7.66$\, \pm \,$1.36 Gyr with no significant gradient out to $2\, R_ {e}$; the average metallicity of the BCG cores is $[Z/H]=0.23\, \pm \, 0.03$ with a negative gradient of Δ[Z/H]/Δ(R/Re) = –0.14$\, \pm \, 0.09$ which flattens beyond $1.2\, R_ {e}$. Velocity dispersion gradients are mostly flat, but a few positive slopes are seen in the most massive galaxies. Emission lines are present in 12 of the BCGs, most often confined to the central $\sim 2\,$ kpc with emission line ratios well-described by a LINER or AGN excitation source. There are 78 companion galaxies identified and 9 have nebular emission lines that indicate recent star formation. The companions with flux ratios of 4:1 and 20:1 within 30 kpc of their BCG’s core are studied. The companion galaxies have a median age of 7.65$\, \pm \,$1.55 Gyr and are high-metallicity systems, with a median [Z/H] = 0.17 ± 0.07. Close spectroscopic companions with higher merging probabilities have an average merging time of 0.5 ± 0.2 Gyr. The average merger rate is 0.08$\, \pm \, 0.12 \,$ Gyr−1 for 4:1 companions and 0.26$\, \pm \, 0.22 \,$ Gyr−1 for 20:1 companions, allowing for an increase in mass of 2.3$\, \pm \,$3.4 per cent Gyr−1 and 3.5$\, \pm \,$3.2 per cent Gyr−1, respectively.

Edwards, Louise O. V. (ORCID:000000029135997X)↗