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At least 577 records · Page 32
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on Te2MoWSeS by Materials Project

WTe2MoTe2MoSe2WS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoSe2 sheet oriented in the (0, 0, 1) direction; one MoTe2 sheet oriented in the (0, 0, 1) direction; one WS2 sheet oriented in the (0, 0, 1) direction; and one WTe2 sheet oriented in the (0, 0, 1) direction. In the MoSe2 sheet, Mo6+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing MoSe6 pentagonal pyramids. All Mo–Se bond lengths are 2.56 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the MoTe2 sheet, Mo6+ is bonded to six equivalent Te2- atoms to form distorted edge-sharing MoTe6 pentagonal pyramids. All Mo–Te bond lengths are 2.71 Å. Te2- is bonded in a 12-coordinate geometry to three equivalent Mo6+ atoms. In the WS2 sheet, W2+ is bonded to six S2- atoms to form distorted edge-sharing WS6 pentagonal pyramids. All W–S bond lengths are 2.47 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted T-shaped geometry to three equivalent W2+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms. In the WTe2 sheet, W2+ is bonded to six Te2- atoms to form distorted edge-sharing WTe6 pentagonal pyramids. All W–Te bond lengths are 2.72 Å. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms. In the second Te2- site, Te2- is bonded in a 12-coordinate geometry to three equivalent W2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Te4Mo3W(SeS)2 by Materials Project

WTe2MoTe2MoSe2MoS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoS2 sheet oriented in the (0, 0, 1) direction; one MoSe2 sheet oriented in the (0, 0, 1) direction; one MoTe2 sheet oriented in the (0, 0, 1) direction; and one WTe2 sheet oriented in the (0, 0, 1) direction. In the MoS2 sheet, Mo+4.67+ is bonded to six equivalent S2- atoms to form distorted edge-sharing MoS6 pentagonal pyramids. All Mo–S bond lengths are 2.47 Å. S2- is bonded in a 3-coordinate geometry to three equivalent Mo+4.67+ atoms. In the MoSe2 sheet, Mo+4.67+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing MoSe6 pentagonal pyramids. All Mo–Se bond lengths are 2.56 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent Mo+4.67+ atoms. In the MoTe2 sheet, Mo+4.67+ is bonded to six equivalent Te2- atoms to form distorted edge-sharing MoTe6 pentagonal pyramids. All Mo–Te bond lengths are 2.71 Å. Te2- is bonded in a 12-coordinate geometry to three equivalent Mo+4.67+ atoms. In the WTe2 sheet, W2+ is bonded to six Te2- atoms to form distorted edge-sharing WTe6 pentagonal pyramids. All W–Te bond lengths are 2.72 Å. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms. In the second Te2- site, Te2- is bonded in a 12-coordinate geometry to three equivalent W2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MoW(SeS)2 by Materials Project

WSe2MoSe2WS2MoS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoS2 sheet oriented in the (0, 0, 1) direction; one MoSe2 sheet oriented in the (0, 0, 1) direction; one WS2 sheet oriented in the (0, 0, 1) direction; and one WSe2 sheet oriented in the (0, 0, 1) direction. In the MoS2 sheet, Mo6+ is bonded to six equivalent S2- atoms to form distorted edge-sharing MoS6 pentagonal pyramids. All Mo–S bond lengths are 2.43 Å. S2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the MoSe2 sheet, Mo6+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing MoSe6 pentagonal pyramids. All Mo–Se bond lengths are 2.53 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the WS2 sheet, W2+ is bonded to six equivalent S2- atoms to form distorted edge-sharing WS6 pentagonal pyramids. All W–S bond lengths are 2.44 Å. S2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms. In the WSe2 sheet, W2+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing WSe6 pentagonal pyramids. All W–Se bond lengths are 2.54 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Te2Mo3W(SeS2)2 by Materials Project

MoTe2MoSe2WS2MoS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoS2 sheet oriented in the (0, 0, 1) direction; one MoSe2 sheet oriented in the (0, 0, 1) direction; one MoTe2 sheet oriented in the (0, 0, 1) direction; and one WS2 sheet oriented in the (0, 0, 1) direction. In the MoS2 sheet, Mo+4.67+ is bonded to six equivalent S2- atoms to form distorted edge-sharing MoS6 pentagonal pyramids. All Mo–S bond lengths are 2.44 Å. S2- is bonded in a 3-coordinate geometry to three equivalent Mo+4.67+ atoms. In the MoSe2 sheet, Mo+4.67+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing MoSe6 pentagonal pyramids. All Mo–Se bond lengths are 2.54 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent Mo+4.67+ atoms. In the MoTe2 sheet, Mo+4.67+ is bonded to six Te2- atoms to form distorted edge-sharing MoTe6 pentagonal pyramids. All Mo–Te bond lengths are 2.70 Å. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 12-coordinate geometry to three equivalent Mo+4.67+ atoms. In the second Te2- site, Te2- is bonded to three equivalent Mo+4.67+ atoms to form distorted corner-sharing TeMo3 cuboctahedra. In the WS2 sheet, W2+ is bonded to six S2- atoms to form distorted edge-sharing WS6 pentagonal pyramids. All W–S bond lengths are 2.45 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted T-shaped geometry to three equivalent W2+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TeMoWSeS2 by Materials Project

WTe2MoSe2WS2MoS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoS2 sheet oriented in the (0, 0, 1) direction; one MoSe2 sheet oriented in the (0, 0, 1) direction; one WS2 sheet oriented in the (0, 0, 1) direction; and one WTe2 sheet oriented in the (0, 0, 1) direction. In the MoS2 sheet, Mo6+ is bonded to six S2- atoms to form distorted edge-sharing MoS6 pentagonal pyramids. All Mo–S bond lengths are 2.45 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted T-shaped geometry to three equivalent Mo6+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the MoSe2 sheet, Mo6+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing MoSe6 pentagonal pyramids. All Mo–Se bond lengths are 2.54 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the WS2 sheet, W2+ is bonded to six equivalent S2- atoms to form distorted edge-sharing WS6 pentagonal pyramids. All W–S bond lengths are 2.45 Å. S2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms. In the WTe2 sheet, W2+ is bonded to six Te2- atoms to form distorted edge-sharing WTe6 pentagonal pyramids. All W–Te bond lengths are 2.71 Å. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms. In the second Te2- site, Te2- is bonded in a 12-coordinate geometry to three equivalent W2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on MoW(SeS)2 by Materials Project

WSe2MoSe2WS2MoS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoS2 sheet oriented in the (0, 0, 1) direction; one MoSe2 sheet oriented in the (0, 0, 1) direction; one WS2 sheet oriented in the (0, 0, 1) direction; and one WSe2 sheet oriented in the (0, 0, 1) direction. In the MoS2 sheet, Mo6+ is bonded to six S2- atoms to form distorted edge-sharing MoS6 pentagonal pyramids. There are three shorter (2.43 Å) and three longer (2.44 Å) Mo–S bond lengths. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted T-shaped geometry to three equivalent Mo6+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the MoSe2 sheet, Mo6+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing MoSe6 pentagonal pyramids. There are three shorter (2.53 Å) and three longer (2.54 Å) Mo–Se bond lengths. Se2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the WS2 sheet, W2+ is bonded to six equivalent S2- atoms to form distorted edge-sharing WS6 pentagonal pyramids. All W–S bond lengths are 2.44 Å. S2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms. In the WSe2 sheet, W2+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing WSe6 pentagonal pyramids. All W–Se bond lengths are 2.54 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Te2Mo3W(SeS2)2 by Materials Project

MoTe2MoSe2WS2MoS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoS2 sheet oriented in the (0, 0, 1) direction; one MoSe2 sheet oriented in the (0, 0, 1) direction; one MoTe2 sheet oriented in the (0, 0, 1) direction; and one WS2 sheet oriented in the (0, 0, 1) direction. In the MoS2 sheet, Mo+4.67+ is bonded to six S2- atoms to form distorted edge-sharing MoS6 pentagonal pyramids. All Mo–S bond lengths are 2.45 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted T-shaped geometry to three equivalent Mo+4.67+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent Mo+4.67+ atoms. In the MoSe2 sheet, Mo+4.67+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing MoSe6 pentagonal pyramids. All Mo–Se bond lengths are 2.54 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent Mo+4.67+ atoms. In the MoTe2 sheet, Mo+4.67+ is bonded to six Te2- atoms to form distorted edge-sharing MoTe6 pentagonal pyramids. All Mo–Te bond lengths are 2.70 Å. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Mo+4.67+ atoms. In the second Te2- site, Te2- is bonded in a 12-coordinate geometry to three equivalent Mo+4.67+ atoms. In the WS2 sheet, W2+ is bonded to six equivalent S2- atoms to form distorted edge-sharing WS6 pentagonal pyramids. All W–S bond lengths are 2.45 Å. S2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Te2Mo3W(Se2S)2 by Materials Project

MoTe2WSe2MoSe2MoS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoS2 sheet oriented in the (0, 0, 1) direction; one MoSe2 sheet oriented in the (0, 0, 1) direction; one MoTe2 sheet oriented in the (0, 0, 1) direction; and one WSe2 sheet oriented in the (0, 0, 1) direction. In the MoS2 sheet, Mo+4.67+ is bonded to six equivalent S2- atoms to form distorted edge-sharing MoS6 pentagonal pyramids. All Mo–S bond lengths are 2.46 Å. S2- is bonded in a 3-coordinate geometry to three equivalent Mo+4.67+ atoms. In the MoSe2 sheet, Mo+4.67+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing MoSe6 pentagonal pyramids. All Mo–Se bond lengths are 2.55 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent Mo+4.67+ atoms. In the MoTe2 sheet, Mo+4.67+ is bonded to six Te2- atoms to form distorted edge-sharing MoTe6 pentagonal pyramids. All Mo–Te bond lengths are 2.71 Å. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Mo+4.67+ atoms. In the second Te2- site, Te2- is bonded in a 12-coordinate geometry to three equivalent Mo+4.67+ atoms. In the WSe2 sheet, W2+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing WSe6 pentagonal pyramids. All W–Se bond lengths are 2.55 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Te2MoWSeS by Materials Project

WTe2MoTe2MoSe2WS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoSe2 sheet oriented in the (0, 0, 1) direction; one MoTe2 sheet oriented in the (0, 0, 1) direction; one WS2 sheet oriented in the (0, 0, 1) direction; and one WTe2 sheet oriented in the (0, 0, 1) direction. In the MoSe2 sheet, Mo6+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing MoSe6 pentagonal pyramids. All Mo–Se bond lengths are 2.56 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the MoTe2 sheet, Mo6+ is bonded to six Te2- atoms to form distorted edge-sharing MoTe6 pentagonal pyramids. All Mo–Te bond lengths are 2.71 Å. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the second Te2- site, Te2- is bonded in a 12-coordinate geometry to three equivalent Mo6+ atoms. In the WS2 sheet, W2+ is bonded to six equivalent S2- atoms to form distorted edge-sharing WS6 pentagonal pyramids. All W–S bond lengths are 2.47 Å. S2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms. In the WTe2 sheet, W2+ is bonded to six equivalent Te2- atoms to form distorted edge-sharing WTe6 pentagonal pyramids. All W–Te bond lengths are 2.72 Å. Te2- is bonded in a 12-coordinate geometry to three equivalent W2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Te2MoW3(SeS2)2 by Materials Project

WTe2WSe2WS2MoS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoS2 sheet oriented in the (0, 0, 1) direction; one WS2 sheet oriented in the (0, 0, 1) direction; one WSe2 sheet oriented in the (0, 0, 1) direction; and one WTe2 sheet oriented in the (0, 0, 1) direction. In the MoS2 sheet, Mo6+ is bonded to six S2- atoms to form distorted edge-sharing MoS6 pentagonal pyramids. All Mo–S bond lengths are 2.45 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted T-shaped geometry to three equivalent Mo6+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the WS2 sheet, W+3.33+ is bonded to six equivalent S2- atoms to form distorted edge-sharing WS6 pentagonal pyramids. All W–S bond lengths are 2.45 Å. S2- is bonded in a 3-coordinate geometry to three equivalent W+3.33+ atoms. In the WSe2 sheet, W+3.33+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing WSe6 pentagonal pyramids. All W–Se bond lengths are 2.55 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent W+3.33+ atoms. In the WTe2 sheet, W+3.33+ is bonded to six Te2- atoms to form distorted edge-sharing WTe6 pentagonal pyramids. All W–Te bond lengths are 2.71 Å. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent W+3.33+ atoms. In the second Te2- site, Te2- is bonded in a 12-coordinate geometry to three equivalent W+3.33+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TeMoWSeS2 by Materials Project

WTe2MoSe2WS2MoS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoS2 sheet oriented in the (0, 0, 1) direction; one MoSe2 sheet oriented in the (0, 0, 1) direction; one WS2 sheet oriented in the (0, 0, 1) direction; and one WTe2 sheet oriented in the (0, 0, 1) direction. In the MoS2 sheet, Mo6+ is bonded to six S2- atoms to form distorted edge-sharing MoS6 pentagonal pyramids. All Mo–S bond lengths are 2.45 Å. There are two inequivalent S2- sites. In the first S2- site, S2- is bonded in a distorted T-shaped geometry to three equivalent Mo6+ atoms. In the second S2- site, S2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the MoSe2 sheet, Mo6+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing MoSe6 pentagonal pyramids. All Mo–Se bond lengths are 2.54 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the WS2 sheet, W2+ is bonded to six equivalent S2- atoms to form distorted edge-sharing WS6 pentagonal pyramids. All W–S bond lengths are 2.45 Å. S2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms. In the WTe2 sheet, W2+ is bonded to six equivalent Te2- atoms to form distorted edge-sharing WTe6 pentagonal pyramids. All W–Te bond lengths are 2.71 Å. Te2- is bonded in a 12-coordinate geometry to three equivalent W2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on TeMoWSe2S by Materials Project

MoTe2WSe2MoSe2WS2 is Molybdenite-derived structured and crystallizes in the trigonal P3m1 space group. The structure is two-dimensional and consists of one MoSe2 sheet oriented in the (0, 0, 1) direction; one MoTe2 sheet oriented in the (0, 0, 1) direction; one WS2 sheet oriented in the (0, 0, 1) direction; and one WSe2 sheet oriented in the (0, 0, 1) direction. In the MoSe2 sheet, Mo6+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing MoSe6 pentagonal pyramids. All Mo–Se bond lengths are 2.55 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the MoTe2 sheet, Mo6+ is bonded to six Te2- atoms to form distorted edge-sharing MoTe6 pentagonal pyramids. There are three shorter (2.70 Å) and three longer (2.71 Å) Mo–Te bond lengths. There are two inequivalent Te2- sites. In the first Te2- site, Te2- is bonded in a 3-coordinate geometry to three equivalent Mo6+ atoms. In the second Te2- site, Te2- is bonded in a 12-coordinate geometry to three equivalent Mo6+ atoms. In the WS2 sheet, W2+ is bonded to six equivalent S2- atoms to form distorted edge-sharing WS6 pentagonal pyramids. All W–S bond lengths are 2.46 Å. S2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms. In the WSe2 sheet, W2+ is bonded to six equivalent Se2- atoms to form distorted edge-sharing WSe6 pentagonal pyramids. All W–Se bond lengths are 2.55 Å. Se2- is bonded in a 3-coordinate geometry to three equivalent W2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Addendum to ICSBEP Logbooks 12r, 13r, 14r and 15r for Polyethylene and Graphite Reflected HEU Metal Critical Experiments

This report documents the experimenters’ data sheets that were recently (2023) discovered for critical experiments with highly enriched uranium metal with polyethylene and graphite reflectors. These data sheets were produced at the time of the measurements, when the dimensional inspection reports for the polyethylene and graphite were available. However, at this writing, those inspection reports are not available but may be in unmarked storage for the Y-12 National Security Complex. However, the data sheets presented herein contain sketches of the experimental configurations and other additional information that is not in the logbooks, such as dimensions and masses of the graphite measurements. This report reproduces the experimental data sheets that complement the logbooks. Some of the data on these sheets and the logbooks can be used to infer the dimensions and masses that are not documented. Some obvious mistakes in the logbook and data sheets have been corrected. In the reproduced data sheets, some of the information is not clearly visible: some information, such as average values, can be obtained from other data in the sheets or logbook. This report should be sent to the International Criticality Safety Benchmark Program at Idaho National Laboratory to complement the existing Oak Ridge Critical Facility logbooks there.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Glacial geology of the Hudson Mountains, Amundsen Sea sector, West Antarctica

The Hudson Mountains are situated in the eastern Amundsen Sea sector of the West Antarctic Ice Sheet, adjacent to Pine Island Glacier. They form a volcanic field of 17 stratovolcanoes and parasitic vents, preserved as nunataks. Two former tributaries of Pine Island Glacier (Larter and Lucchitta glaciers) flow through the mountains. Here we present a detailed study of the glacial geology of the area. We describe field observations and measurements of geomorphological features from 15 of the nunataks, meltwater ponds found on the surface of three nunataks and supraglacial features (ice dolines) from two sites near the present grounding line. Together these provide constraints on the past ice sheet extent, flow pathways and thermal regime, and enhance our understanding of the present hydrological regime – all of which are important as context for the observed modern ice sheet behaviour. We find evidence suggesting that all nunataks in the Hudson Mountains were covered by ice during the Last Glacial Maximum (defined here as 26.5-19 ka) and have since deglaciated. Faceted and polished erratic cobbles and boulders of exotic lithologies (syenites, alkali granites, granites, granodiorites, tonalites and gabbros) are numerous and perched on nunatak surfaces. A marked difference between the dominant erratic lithologies on nunataks adjacent to Pine Island Glacier (granite) and Lucchitta Glacier (granodiorite-tonalite) indicates that the ice sheet was transporting clasts from at least two distinct upstream source regions. The similarity in degree of weathering suggests, however, that all the erratics were transported by one phase of (warm-based) glaciation; their presence on or close to the summits of all except one nunatak indicates that the ice sheet during that time was at least 700 m thicker than present. These results are consistent with ice sheet model simulations which suggest that all nunataks in the Hudson Mountains were completely submerged by the Last Glacial Maximum ice sheet.

58 GEOSCIENCES↗
DOE OSTI2020

Self-powered and reversible light-directed electrophoretic deposition device for use in smart windows and photodetector displays

According to one embodiment, a method includes receiving light on a photoconductive layer of an electrophoretic deposition (EPD) device, the EPD device having a chamber defined by a first sheet, a second sheet and a spacer between the first and second sheets, where the first sheet is nonopaque and includes the photoconductive layer, where the second sheet is nonopaque and spaced from the first sheet, where a fluidic solution having a plurality of particles is in the chamber. The particles in the solution are attracted from suspension to illuminated portions of the photoconductive layer in the absence of an external voltage applied to the first and second sheets. The particles become deposited on the illuminated portions of the photoconductive layer.

42 ENGINEERING↗
DOE OSTI2024

Crystallography Reveals Metal‐Triggered Restructuring of β‐Hairpins

Abstract Metal binding to β‐sheets occurs in many metalloproteins and is also implicated in the pathology of Alzheimer's disease. De novo designed metallo‐β‐sheets have been pursued as models and mimics of these proteins. However, no crystal structures of canonical β‐sheet metallopeptides have yet been obtained, in stark contrast to many examples for ɑ‐helical metallopeptides, leading to a poor understanding for their chemistry. To address this, we have engineered tryptophan zippers, stable 12‐residue β‐sheet peptides, to bind Cu(II) ions and obtained crystal structures through single crystal X‐ray diffraction (SC‐XRD). We find that metal binding triggers several unexpected supramolecular assemblies that demonstrate the range of higher‐order structures available to metallo‐β‐sheets. Overall, these findings underscore the importance of crystallography in elucidating the rich structural landscape of metallo‐β‐sheet peptides.

Thuc Dang, Viet↗
DOE OSTI2020

Solvent–Solvent Correlations across Graphene: The Effect of Image Charges

Wetting experiments show pure graphene to be weakly hydrophilic, but its contact angle (CA) also reflects the character of the supporting material. Measurements and Molecular Dynamics simulations on suspended and supported graphene often reveal a CA reduction due to the presence of the supporting substrate. A similar reduction is consistently observed when graphene is wetted from both sides. The effect has been attributed to transparency to molecular interactions across the graphene sheet, however, the possibility of substrate-induced graphene polarization has also been considered. Computer simulations of CA on graphene have so far been determined by ignoring the material’s conducting properties. We improve the graphene model by incorporating its conductivity according to the Constant Applied Potential Molecular Dynamics. Using this method, we compare the wettabilities of suspended graphene and graphene supported by water by measuring the CA of cylindrical water drops on the sheets. The inclusion of graphene conductivity and concomitant polarization effects lead to a lower CA on suspended graphene but the CA reduction is significantly bigger when the sheets are also wetted from the opposite side. The stronger adhesion is accompanied by a profound change in the correlations among water molecules across the sheet. While partial charges on water molecules interacting across an insulator sheet attract charges of the opposite sign, apparent attraction among like charges is manifested across the conducting graphene. The change is associated with graphene polarization, as the image charges inside the conductor attract equally signed partial charges of water molecules on both sides of the sheet. Additionally, by using a non-polar liquid (diiodomethane), we affirm a detectable wetting translucency when liquid-liquid forces are dominated by dispersive interactions. Furthermore, our findings are important for predictive modeling toward a variety of applications including sensors, fuel cell membranes, water filtration, and graphene-based electrode materials in high-performance supercapacitors.

77 NANOSCIENCE AND NANOTECHNOLOGY↗
DOE OSTI2025

Moisture Effect on Chitin Decomposition Biogeochemistry

This dataset contains data files for multiple measurements of sample biogeochemistry and function collected for the Soils SFA Chitin Decomposition project in task 2.2. Samples were generated from soil incubated under different moisture levels, with and without chitin. Each sheet in the file refers to the preprocessed data collected. Sheet 1 "Respiration" measures CO2 production daily for the course of the incubation. Sheet 2 "Biomass" contains the microbial biomass and salt extractable measurements for carbon and nitrogen. Sheet 3 "Chitin" is for HPLC measured chitin from each sample. Sheet 4 "Extracellular Enzyme Assays" records the level of activity for several enzyme assays. Sheet 5 "Enzyme Kinetics" measures degradation of substrate over time for all samples.

Reichart, Nicholas J [Pacific Northwest National L↗