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At least 397 records · Page 22
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Materials Data on CsRbMg6 by Materials Project

CsRbMg6 is Magnesium tetraboride-derived structured and crystallizes in the monoclinic Pm space group. The structure is three-dimensional. Cs is bonded in a 10-coordinate geometry to two equivalent Rb and eight Mg atoms. Both Cs–Rb bond lengths are 3.77 Å. There are a spread of Cs–Mg bond distances ranging from 3.96–4.27 Å. Rb is bonded in a 8-coordinate geometry to two equivalent Cs and seven Mg atoms. There are a spread of Rb–Mg bond distances ranging from 3.91–4.27 Å. There are six inequivalent Mg sites. In the first Mg site, Mg is bonded in a 8-coordinate geometry to one Cs, one Rb, and six Mg atoms. There are two shorter (3.02 Å) and four longer (3.24 Å) Mg–Mg bond lengths. In the second Mg site, Mg is bonded in a 7-coordinate geometry to one Cs and six Mg atoms. There are two shorter (3.02 Å) and four longer (3.24 Å) Mg–Mg bond lengths. In the third Mg site, Mg is bonded in a 8-coordinate geometry to two equivalent Cs, two equivalent Rb, and four Mg atoms. Both Mg–Mg bond lengths are 3.07 Å. In the fourth Mg site, Mg is bonded in a 8-coordinate geometry to two equivalent Cs, two equivalent Rb, and four Mg atoms. There are one shorter (3.03 Å) and one longer (3.11 Å) Mg–Mg bond lengths. In the fifth Mg site, Mg is bonded in a 8-coordinate geometry to two equivalent Rb and six Mg atoms. In the sixth Mg site, Mg is bonded in a 8-coordinate geometry to two equivalent Cs and six Mg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsZrOF5 by Materials Project

CsZrOF5 crystallizes in the triclinic P-1 space group. The structure is three-dimensional. Cs is bonded in a 11-coordinate geometry to one O and ten F atoms. The Cs–O bond length is 3.46 Å. There are a spread of Cs–F bond distances ranging from 3.04–3.68 Å. Zr is bonded in a 8-coordinate geometry to one O and seven F atoms. The Zr–O bond length is 2.28 Å. There are a spread of Zr–F bond distances ranging from 2.03–2.29 Å. O is bonded in a single-bond geometry to one Cs and one Zr atom. There are five inequivalent F sites. In the first F site, F is bonded in a 1-coordinate geometry to two equivalent Cs and one Zr atom. In the second F site, F is bonded in a distorted single-bond geometry to two equivalent Cs and one Zr atom. In the third F site, F is bonded in a distorted trigonal non-coplanar geometry to one Cs and two equivalent Zr atoms. In the fourth F site, F is bonded in a distorted single-bond geometry to three equivalent Cs and one Zr atom. In the fifth F site, F is bonded in a distorted water-like geometry to two equivalent Cs and two equivalent Zr atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs2Na6Al6Ge7O30 by Materials Project

Cs2Na6Al6Ge7O30 crystallizes in the trigonal P3 space group. The structure is three-dimensional. there are two inequivalent Cs sites. In the first Cs site, Cs is bonded in a 6-coordinate geometry to six equivalent O atoms. There are three shorter (3.19 Å) and three longer (3.64 Å) Cs–O bond lengths. In the second Cs site, Cs is bonded in a 6-coordinate geometry to six equivalent O atoms. There are three shorter (3.19 Å) and three longer (3.65 Å) Cs–O bond lengths. There are two inequivalent Na sites. In the first Na site, Na is bonded to five O atoms to form distorted NaO5 square pyramids that share corners with three AlO4 tetrahedra, corners with three GeO4 tetrahedra, corners with two equivalent NaO5 trigonal bipyramids, and an edgeedge with one GeO6 octahedra. There are a spread of Na–O bond distances ranging from 2.34–2.58 Å. In the second Na site, Na is bonded to five O atoms to form distorted NaO5 trigonal bipyramids that share corners with two equivalent GeO6 octahedra, corners with two equivalent NaO5 square pyramids, corners with three AlO4 tetrahedra, and corners with three GeO4 tetrahedra. The corner-sharing octahedra tilt angles range from 21–62°. There are a spread of Na–O bond distances ranging from 2.38–2.49 Å. There are two inequivalent Al sites. In the first Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share corners with two equivalent NaO5 square pyramids, corners with four GeO4 tetrahedra, and a cornercorner with one NaO5 trigonal bipyramid. There are a spread of Al–O bond distances ranging from 1.76–1.78 Å. In the second Al site, Al is bonded to four O atoms to form AlO4 tetrahedra that share a cornercorner with one NaO5 square pyramid, corners with four GeO4 tetrahedra, and corners with two equivalent NaO5 trigonal bipyramids. There are a spread of Al–O bond distances ranging from 1.76–1.78 Å. There are three inequivalent Ge sites. In the first Ge site, Ge is bonded to four O atoms to form GeO4 tetrahedra that share corners with two equivalent NaO5 square pyramids, corners with four AlO4 tetrahedra, and a cornercorner with one NaO5 trigonal bipyramid. There is two shorter (1.76 Å) and two longer (1.77 Å) Ge–O bond length. In the second Ge site, Ge is bonded to four O atoms to form GeO4 tetrahedra that share a cornercorner with one NaO5 square pyramid, corners with four AlO4 tetrahedra, and corners with two equivalent NaO5 trigonal bipyramids. There is one shorter (1.76 Å) and three longer (1.77 Å) Ge–O bond length. In the third Ge site, Ge is bonded to six O atoms to form GeO6 octahedra that share corners with six equivalent NaO5 trigonal bipyramids and edges with three equivalent NaO5 square pyramids. There is three shorter (1.86 Å) and three longer (1.88 Å) Ge–O bond length. There are ten inequivalent O sites. In the first O site, O is bonded in a distorted trigonal planar geometry to one Na, one Al, and one Ge atom. In the second O site, O is bonded in a distorted trigonal planar geometry to one Na, one Al, and one Ge atom. In the third O site, O is bonded in a distorted T-shaped geometry to two Na and one Ge atom. In the fourth O site, O is bonded in a distorted trigonal non-coplanar geometry to two Na and one Ge atom. In the fifth O site, O is bonded in a 2-coordinate geometry to two equivalent Cs, one Al, and one Ge atom. In the sixth O site, O is bonded in a 2-coordinate geometry to two equivalent Cs, one Al, and one Ge atom. In the seventh O site, O is bonded in a distorted trigonal planar geometry to one Na, one Al, and one Ge atom. In the eighth O site, O is bonded in a distorted trigonal non-coplanar geometry to one Na, one Al, and one Ge atom. In the ninth O site, O is bonded in a distorted trigonal planar geometry to one Na, one Al, and one Ge atom. In the tenth O site, O is bonded in a distorted trigonal planar geometry to one Na, one Al, and one Ge atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsHg by Materials Project

CsHg is delta Molybdenum Boride-like structured and crystallizes in the triclinic P-1 space group. The structure is three-dimensional. there are two inequivalent Cs sites. In the first Cs site, Cs is bonded in a 6-coordinate geometry to seven Hg atoms. There are a spread of Cs–Hg bond distances ranging from 4.02–4.44 Å. In the second Cs site, Cs is bonded in a 7-coordinate geometry to seven Hg atoms. There are a spread of Cs–Hg bond distances ranging from 3.95–4.37 Å. There are two inequivalent Hg sites. In the first Hg site, Hg is bonded in a 9-coordinate geometry to seven Cs and two equivalent Hg atoms. There are one shorter (3.09 Å) and one longer (3.14 Å) Hg–Hg bond lengths. In the second Hg site, Hg is bonded in a 9-coordinate geometry to seven Cs and two equivalent Hg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs3SbH2S4O by Materials Project

Cs3SbH2S4O crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional. there are three inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 1-coordinate geometry to three H1+, seven S2-, and one O2- atom. There are a spread of Cs–H bond distances ranging from 3.35–3.50 Å. There are a spread of Cs–S bond distances ranging from 3.60–3.85 Å. The Cs–O bond length is 3.53 Å. In the second Cs1+ site, Cs1+ is bonded in a 9-coordinate geometry to one H1+, seven S2-, and one O2- atom. The Cs–H bond length is 3.29 Å. There are a spread of Cs–S bond distances ranging from 3.68–4.00 Å. The Cs–O bond length is 3.45 Å. In the third Cs1+ site, Cs1+ is bonded in a 7-coordinate geometry to one H1+, four S2-, and two equivalent O2- atoms. The Cs–H bond length is 3.33 Å. There are a spread of Cs–S bond distances ranging from 3.47–3.76 Å. There are one shorter (3.32 Å) and one longer (3.43 Å) Cs–O bond lengths. Sb5+ is bonded in a tetrahedral geometry to four S2- atoms. There are one shorter (2.35 Å) and three longer (2.37 Å) Sb–S bond lengths. There are two inequivalent H1+ sites. In the first H1+ site, H1+ is bonded in a single-bond geometry to two Cs1+ and one O2- atom. The H–O bond length is 1.00 Å. In the second H1+ site, H1+ is bonded in a single-bond geometry to three Cs1+ and one O2- atom. The H–O bond length is 0.99 Å. There are four inequivalent S2- sites. In the first S2- site, S2- is bonded to five Cs1+ and one Sb5+ atom to form distorted edge-sharing SCs5Sb octahedra. In the second S2- site, S2- is bonded in a 1-coordinate geometry to five Cs1+ and one Sb5+ atom. In the third S2- site, S2- is bonded in a 1-coordinate geometry to four Cs1+ and one Sb5+ atom. In the fourth S2- site, S2- is bonded in a distorted single-bond geometry to four Cs1+ and one Sb5+ atom. O2- is bonded in a water-like geometry to four Cs1+ and two H1+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsNa2 by Materials Project

Na2Cs is Hexagonal Laves structured and crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. Cs is bonded in a 12-coordinate geometry to four equivalent Cs and twelve Na atoms. There are a spread of Cs–Cs bond distances ranging from 4.73–4.79 Å. There are a spread of Cs–Na bond distances ranging from 4.55–4.58 Å. There are four inequivalent Na sites. In the first Na site, Na is bonded to six equivalent Cs and six Na atoms to form a mixture of corner, edge, and face-sharing NaCs6Na6 cuboctahedra. There are two shorter (3.88 Å) and four longer (3.89 Å) Na–Na bond lengths. In the second Na site, Na is bonded to six equivalent Cs and six Na atoms to form a mixture of corner, edge, and face-sharing NaCs6Na6 cuboctahedra. There are a spread of Na–Na bond distances ranging from 3.89–3.91 Å. In the third Na site, Na is bonded to six equivalent Cs and six Na atoms to form a mixture of corner, edge, and face-sharing NaCs6Na6 cuboctahedra. There are one shorter (3.88 Å) and one longer (3.90 Å) Na–Na bond lengths. In the fourth Na site, Na is bonded to six equivalent Cs and six Na atoms to form a mixture of corner, edge, and face-sharing NaCs6Na6 cuboctahedra.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs3LiPb4 by Materials Project

Cs3LiPb4 crystallizes in the orthorhombic Cmcm space group. The structure is three-dimensional. there are two inequivalent Cs sites. In the first Cs site, Cs is bonded in a 2-coordinate geometry to eight Pb atoms. There are a spread of Cs–Pb bond distances ranging from 4.06–4.45 Å. In the second Cs site, Cs is bonded in a 1-coordinate geometry to seven Pb atoms. There are a spread of Cs–Pb bond distances ranging from 3.89–4.21 Å. Li is bonded in a distorted hexagonal planar geometry to six Pb atoms. There are two shorter (3.16 Å) and four longer (3.26 Å) Li–Pb bond lengths. There are two inequivalent Pb sites. In the first Pb site, Pb is bonded in a 2-coordinate geometry to five Cs, two equivalent Li, and three Pb atoms. There are two shorter (3.14 Å) and one longer (3.25 Å) Pb–Pb bond lengths. In the second Pb site, Pb is bonded in a 10-coordinate geometry to six Cs, one Li, and three Pb atoms. The Pb–Pb bond length is 3.10 Å.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsMg6C by Materials Project

CsMg6C crystallizes in the orthorhombic Amm2 space group. The structure is three-dimensional. Cs is bonded in a 12-coordinate geometry to two equivalent Cs and ten Mg atoms. Both Cs–Cs bond lengths are 3.38 Å. There are a spread of Cs–Mg bond distances ranging from 3.46–4.23 Å. There are four inequivalent Mg sites. In the first Mg site, Mg is bonded in a distorted L-shaped geometry to one Cs, two equivalent Mg, and two equivalent C atoms. Both Mg–Mg bond lengths are 3.24 Å. Both Mg–C bond lengths are 2.26 Å. In the second Mg site, Mg is bonded in a 10-coordinate geometry to two equivalent Cs and eight Mg atoms. There are a spread of Mg–Mg bond distances ranging from 3.32–3.38 Å. In the third Mg site, Mg is bonded in a single-bond geometry to two equivalent Cs, three Mg, and one C atom. The Mg–Mg bond length is 3.39 Å. The Mg–C bond length is 2.36 Å. In the fourth Mg site, Mg is bonded to two equivalent Cs and ten Mg atoms to form a mixture of face and corner-sharing MgCs2Mg10 cuboctahedra. Both Mg–Mg bond lengths are 3.38 Å. C is bonded in a 6-coordinate geometry to six Mg atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Mercury and Radiocesium Accumulation and Associations With Sublethal Endpoints in the Florida Green Watersnake ( Nerodia floridana )

Mercury (Hg) and radiocesium ( 137 Cs) are well-known environmental contaminants with the potential to impact the health of humans and wildlife. Snakes have several characteristics conducive to studying environmental contamination but have rarely been included in the monitoring of polluted sites. We investigated the bioaccumulation of Hg and 137 Cs and associations with sublethal effects (standard metabolic rate [SMR] and hemoparasite infections) in Florida green watersnakes (Nerodia floridana). We captured 78 snakes from three former nuclear cooling reservoirs on the US Department of Energy's Savannah River Site in South Carolina (USA). For captured snakes, we (1) determined whole-body 137 Cs, (2) quantified total Hg (THg) using snake tail clips, (3) conducted hemoparasite counts, and (4) measured the SMR. We used multiple regression models to determine associations among snake body size, capture location, sex, tail THg, whole-body 137 Cs, Hepatozoon spp. prevalence and parasitemia, and SMR. Average whole-body 137 Cs (0.23 ± 0.08 Becquerels [Bq]/g; range: 0.00–1.02 Bq/g) was correlated with snake body size and differed significantly by capture site (Pond B: 0.67 ± 0.05 Bq/g; Par Pond: 0.10 ± 0.02 Bq/g; Pond 2: 0.03 ± 0.02 Bq/g). Tail THg (0.33 ± 0.03 mg/kg dry wt; range: 0.16–2.10 mg/kg) was significantly correlated with snake body size but did not differ by capture site. We found no clear relationship between SMR and contaminant burdens. However, models indicated that the prevalence of Hepatozoon spp. in snakes was inversely related to increasing whole-body 137 Cs burdens. Our results indicate the bioaccumulation of Hg and 137 Cs in N. floridana and further demonstrate the utility of aquatic snakes as bioindicators. Furthermore, our results also suggest a decrease in Hepatozoon spp. prevalence related to increased burdens of 137 Cs. Although the results are intriguing, further research is needed to understand the dynamics between 137 Cs and Hepatozoon spp. infections in semiaquatic snakes.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Stabilization of Preternatural Barium Oxidation States as an Unexpected Byproduct of β-Decay: Discovery of a New Halide Semiconductor Alloy

137 Cs has a wide range of roles in the nuclear industry. The solid material, safely encapsulated in CsCl as 137 CsCl, is stored as fission product waste from nuclear power production and legacy waste from nuclear weapons production; it has also served as a radiation source in food and sewage irradiators as well as medical devices. However, because of the solubility of the chloride salt and the relatively high specific activity of 137 Cs, damaged or broken capsules can lead to severe radiological accidents. Safe capsule design and material recycling are complicated by the unclear structural evolution during β-decay, which remains ambiguous due to the differing oxidation states of Cs (1+) and Ba (2+). Here, in this study, we use first-principles calculations to investigate the evolving structure–property relationships of Cs 1–x Ba x Cl during β-decay. Despite the well-established 2+ formal oxidation state of alkali-earth metals, we find that Ba 1+ can be stabilized in the form of a mixed-valence alloy at low concentrations. Specifically, we identify three regimes for the β-decay of 137 Cs into CsCl: Ba-doped CsCl (Ba ≤ 14%), wherein Ba has the expected 2+ oxidation state; Cs–Ba–Cl alloys, where Ba has a mix of the usual Ba 2+ and highly unusual Ba 1+ oxidation state in the form of a quasi-disordered mixed-valence alloy (Ba = 25%); and phase separation into a CsCl + BaCl 2 + Ba (m) mechanical mixture, where Ba reverts to its expected 2+ oxidation state (Ba > 25%). Surprisingly, the Cs 0.75 Ba 0.25 Cl mixed-valence alloy is a narrow indirect band gap semiconductor (1.05 eV) despite the insulating nature of both CsCl and BaCl 2 . It also exhibits strongly excitonic polarized optical properties, has glass-like ultralow thermal conductivity (directional average of 0.21 W/mK at 300 K), and shows greater resistance to deformation under both tensile and volumetric strengths compared with the original CsCl structure (e.g., shear and Young’s modulus of 9.04 and 31.62 GPa, respectively). These findings imply that transmutation of 137 Cs leads to highly unusual chemical bonding that stabilizes Ba 1+ in local regions of the quasi-disordered Cs 0.25 Ba 0.75 Cl, resulting in anomalous physical properties. Moreover, this discovery provides valuable insight for safe nuclear waste capsule design, which can aid in preventing environmental or human exposure to radioactive materials.

Fuhr, Addis S. [Oak Ridge National Laboratory (ORN↗
DOE OSTI2020

Revisiting heat treatment and surface activation of GaAs photocathodes: In situ studies using scanning tunneling microscopy and photoelectron spectroscopy

The lifetime of GaAs photocathodes in polarized electron guns is limited due to the delicate activation layer. An atomically clean and smooth GaAs surface is needed to deposit a robust activation layer, such as Cs 2 Te, with longer lifetime compared to traditional (Cs,O) activation. A previous experiment with Cs 2 Te activation on GaAs used heat cleaning temperatures around 400°C to avoid an increase in surface roughness [Bae et al., Appl. Phys. Lett. 112, 154101 (2018)]. Furthermore, high-temperature heat cleaning around 580°C, which results in a relatively contamination-free surface, could be one possible way to improve quantum efficiency. However, one should be cautious about surface roughness degradation during high-temperature heat cleaning. In this paper, we report results of surface roughness measurements on native, heat cleaned, and (Cs,O) activated GaAs photocathodes under vacuum. The results, measured by ultrahigh vacuum scanning tunneling microscopy, show that the surface roughness improves as the heat cleaning temperature is increased, by at least a factor of three for 580°C heat cleaning, compared to the native sample. Activation with (Cs,O) is shown to increase surface roughness by a factor of four compared to a 580°C heat cleaned sample. This confirms that high-temperature heat cleaning can be useful for depositing good quality robust activation layers on GaAs. Additionally, we also report chemical analysis for each step of preparation for p-doped GaAs photocathodes using X-ray photoelectron spectroscopy (XPS), angle-resolved XPS, and ultraviolet photoelectron spectroscopy. Our results indicate that the (Cs,O) activation layer forms a sandwich structure consists of Cs and oxygen. We found no formation of any specific compound such as Cs 2 O or Cs 11 O 3 .

43 PARTICLE ACCELERATORS↗
DOE OSTI2024

Cooled Spray Technology for Particulate Reduction in a Heavy-Duty Engine

Cooled spray (CS) technology passively reduces particulate matter (PM) emissions from diesel engines compared to non-CS-equipped diesel engines. CS inserts are mounted near the injector nozzle and control mixing so that the fuel and air can premix while limiting combustion near fuel-rich zones, thereby reducing the formation of particulate matter. CS components contain no moving parts and could be installed as a retrofit or built into new engines. However, CS technology is early in its development, and further investigations are needed to understand the overall performance implications and practicality of the technology. In this paper, we investigate several important aspects of CS, providing a clearer picture of some challenges and potential benefits of CS. Two alignment techniques are used to characterize measurement ease and bias, namely, an optical alignment and spray-plug impact alignment. While the optical technique facilitates alignment more easily, a bias was measured between the optical and spray-plug techniques, suggesting the optical technique may have insufficient accuracy without additional corrections. We also evaluate the engine performance of a well-aligned and poorly aligned CS insert, compared to the baseline configuration. The poorly aligned insert shows slower combustion than the baseline and mixed overall performance. However, the well-aligned insert shows faster combustion than the baseline and PM emission reduction at most operating conditions, with some conditions showing PM reduction up to 80%. Furthermore, the results of this paper highlight the alignment challenges of CS technology as well as the potential PM reduction benefit of the technology.

33 ADVANCED PROPULSION SYSTEMS↗
DOE OSTI2024

Assessing Suitable Geologic Carbon Storage Sites Across Utah

Utah has a wealth of potential geological reservoirs for carbon dioxide storage (CS) and a long history of geologic research resulting in an abundance of available subsurface data to evaluate CS potential. Reservoirs may include sandstone, carbonate, and basalt; these rock types are plentiful in Utah’s subsurface and the complex Phanerozoic history throughout the state requires evaluating each geologic region individually for promising reservoir-seal pairs for CO2 storage. Classifying Utah by geologic provinces (or “geo-regions”) allows for customized thinking about suitable CS reservoir and seal distribution, CO2 point sources, land use, and existing infrastructure. Preliminary results from this study highlight the geologic CS potential across 15 geo-regions. Four regions stand out as having high CS potential: the Uinta Basin, San Rafael Swell, Paradox Basin, and the southern Basin and Range Province. The Uinta Basin and San Rafael Swell geo-regions are well suited for CS and have several projects ongoing to evaluate Cretaceous Frontier and Naturita Formations, Jurassic Navajo Sandstone and Entrada Sandstone, and Permian Weber Sandstone reservoir units that lie beneath robust sealing units like the ~5000-ft-thick Mancos Shale and Carmel Formation. Reservoirs such as the Navajo and Weber Sandstones have been demonstrated to be suitable reservoirs through a long history of oil and gas exploration in Utah. New areas of interest include the southern Basin and Range in southwest Utah, where the Jurassic Navajo Sandstone is overlain by the sealing Carmel Formation at suitable depths (>3000 ft), and has good porosities based on outcrop analogue data. Just to the north (e.g., central Basin and Range), legacy wells and 2D seismic data show possible salt and subsurface basalt flows that may provide additional possible CS reservoirs and seals. This geo-region also has the advantage of being coupled with geothermal energy resources that may be used to power burgeoning direct air capture technologies. In the Paradox Basin of southeastern Utah, the Leadville Limestone is a potential storage reservoir beneath the thick (4000–5000 ft), salt-bearing Pennsylvanian Paradox Formation. Although the northern and western parts of Utah offer CS potential, these areas typically contain less infrastructure and subsurface penetrations, creating geologic uncertainty associated with subsurface seals and reservoirs due to a lack of data. Overall, this statewide assessment and ranking is the first step to aid in evaluating CS potential across Utah and provides a foundation for future research in the most favorable locations.

58 GEOSCIENCES↗
DOE OSTI2024

On the connection between least squares, regularization, and classical shadows

Classical shadows (CS) offer a resource-efficient means to estimate quantum observables, circumventing the need for exhaustive state tomography. Here, we clarify and explore the connection between CS techniques and least squares (LS) and regularized least squares (RLS) methods commonly used in machine learning and data analysis. By formal identification of LS and RLS ``shadows'' completely analogous to those in CS---namely, point estimators calculated from the empirical frequencies of single measurements---we show that both RLS and CS can be viewed as regularizers for the underdetermined regime, replacing the pseudoinverse with invertible alternatives. Through numerical simulations, we evaluate RLS and CS from three distinct angles: the tradeoff in bias and variance, mismatch between the expected and actual measurement distributions, and the interplay between the number of measurements and number of shots per measurement. Compared to CS, RLS attains lower variance at the expense of bias, is robust to distribution mismatch, and is more sensitive to the number of shots for a fixed number of state copies---differences that can be understood from the distinct approaches taken to regularization. Conceptually, our integration of LS, RLS, and CS under a unifying ``shadow'' umbrella aids in advancing the overall picture of CS techniques, while practically our results highlight the tradeoffs intrinsic to these measurement approaches, illuminating the circumstances under which either RLS or CS would be preferred, such as unverified randomness for the former or unbiased estimation for the latter.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2022

Corrosion of Stainless and Carbon Steel in Aqueous Piperazine for CO2 Capture

Current obstacles that prevent commercial implementation of amine-scrubbing CO2 capture are the high costs. Reducing capital costs by appropriate selection of construction materials, which requires knowledge of material corrosion performance for the process, will improve the economic feasibility of this technology. Corrosion was evaluated in three pilot plant campaigns using aqueous piperazine with the Advanced Stripper (PZAS). 316L stainless steel (SS) experienced higher corrosion than 304 SS and 2205 duplex SS, and the corrosion rate showed strong dependence on the temperature. 304 and 2205 performed well at all locations and should be good construction materials for PZAS. Degraded PZ exacerbated 316L corrosion, and removal of PZ degradation products using a carbon adsorption bed significantly reduced corrosion. Carbon steel (CS) corrosion showed a weak temperature effect because the corrosion was more dependent on the protective siderite film. The protectiveness of the films was related to fluid velocity. Ni-based alloys corroded in PZ, and the rate increased with temperature. Corrosion of C1010 CS and SS (304, 316L, 430) was measured at absorber and water wash conditions on the bench-scale. Corrosion rate decreases with increasing PZ. 8 With more than 0.003 m PZ in solution, CS has acceptable corrosion performance. Corrosion of CS increases with increasing partial pressure of CO2, suggesting loading is another dominant parameter for carbon steel corrosion. Temperature has a less significant effect than PZ concentration and loading. CS corrosion increases with increasing flow velocity at both absorber and water wash conditions. SS had little corrosion at this lower temperature. Performance of siderite (FeCO3) protective films on CS was studied at representative stripper conditions on the bench-scale. Siderite films can deposit on the surface of CS in CO2-loaded PZ solution at temperatures >100 °C and protect CS from corrosion. The protection may fail in degraded PZ. Ethylenediamine (EDA) is one of the major contributors for the loss of film protectiveness or can be the surrogate for the effect of PZ degradation on siderite film protection. A link between protectiveness and the apparent density of siderite films was discovered. The apparent density of siderite films decreases with increasing flow velocity and decreasing CO2 loading, resulting in higher corrosion of CS.

Liu, Ching-Ting↗
DOE OSTI2020

Materials Data on Cs2PtC2(OF)4 by Materials Project

Cs2PtC2(OF)4 crystallizes in the triclinic P1 space group. The structure is three-dimensional. there are four inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded to four O2- and eight F1- atoms to form distorted CsO4F8 cuboctahedra that share corners with two equivalent CsO4F8 cuboctahedra, a cornercorner with one PtO2F4 octahedra, faces with two equivalent CsO4F8 cuboctahedra, and faces with three PtO2F4 octahedra. The corner-sharing octahedral tilt angles are 17°. There are a spread of Cs–O bond distances ranging from 3.25–3.36 Å. There are a spread of Cs–F bond distances ranging from 3.13–3.28 Å. In the second Cs1+ site, Cs1+ is bonded in a 11-coordinate geometry to four O2- and seven F1- atoms. There are a spread of Cs–O bond distances ranging from 3.19–3.41 Å. There are a spread of Cs–F bond distances ranging from 3.11–3.29 Å. In the third Cs1+ site, Cs1+ is bonded to four O2- and eight F1- atoms to form distorted CsO4F8 cuboctahedra that share corners with two equivalent CsO4F8 cuboctahedra, a cornercorner with one PtO2F4 octahedra, faces with two equivalent CsO4F8 cuboctahedra, and faces with three PtO2F4 octahedra. The corner-sharing octahedral tilt angles are 16°. There are a spread of Cs–O bond distances ranging from 3.19–3.32 Å. There are a spread of Cs–F bond distances ranging from 3.16–3.33 Å. In the fourth Cs1+ site, Cs1+ is bonded in a 11-coordinate geometry to four O2- and seven F1- atoms. There are a spread of Cs–O bond distances ranging from 3.22–3.44 Å. There are a spread of Cs–F bond distances ranging from 3.12–3.32 Å. There are two inequivalent Pt2+ sites. In the first Pt2+ site, Pt2+ is bonded to two O2- and four F1- atoms to form PtO2F4 octahedra that share a cornercorner with one CsO4F8 cuboctahedra and faces with three CsO4F8 cuboctahedra. Both Pt–O bond lengths are 2.01 Å. There are a spread of Pt–F bond distances ranging from 1.97–2.01 Å. In the second Pt2+ site, Pt2+ is bonded to two O2- and four F1- atoms to form PtO2F4 octahedra that share a cornercorner with one CsO4F8 cuboctahedra and faces with three CsO4F8 cuboctahedra. There are one shorter (2.01 Å) and one longer (2.02 Å) Pt–O bond lengths. There are a spread of Pt–F bond distances ranging from 1.97–2.01 Å. There are four inequivalent C4+ sites. In the first C4+ site, C4+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.23 Å) and one longer (1.32 Å) C–O bond length. In the second C4+ site, C4+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.22 Å) and one longer (1.33 Å) C–O bond length. In the third C4+ site, C4+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.23 Å) and one longer (1.32 Å) C–O bond length. In the fourth C4+ site, C4+ is bonded in a bent 120 degrees geometry to two O2- atoms. There is one shorter (1.22 Å) and one longer (1.33 Å) C–O bond length. There are eight inequivalent O2- sites. In the first O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Cs1+, one Pt2+, and one C4+ atom. In the second O2- site, O2- is bonded in a single-bond geometry to two Cs1+ and one C4+ atom. In the third O2- site, O2- is bonded in a distorted water-like geometry to two Cs1+, one Pt2+, and one C4+ atom. In the fourth O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Cs1+, one Pt2+, and one C4+ atom. In the fifth O2- site, O2- is bonded in a single-bond geometry to two Cs1+ and one C4+ atom. In the sixth O2- site, O2- is bonded in a single-bond geometry to two Cs1+ and one C4+ atom. In the seventh O2- site, O2- is bonded in a distorted bent 120 degrees geometry to two Cs1+, one Pt2+, and one C4+ atom. In the eighth O2- site, O2- is bonded in a single-bond geometry to two Cs1+ and one C4+ atom. There are eight inequivalent F1- sites. In the first F1- site, F1- is bonded in a distorted single-bond geometry to four Cs1+ and one Pt2+ atom. In the second F1- site, F1- is bonded in a distorted single-bond geometry to four Cs1+ and one Pt2+ atom. In the third F1- site, F1- is bonded in a distorted single-bond geometry to four Cs1+ and one Pt2+ atom. In the fourth F1- site, F1- is bonded in a distorted single-bond geometry to four Cs1+ and one Pt2+ atom. In the fifth F1- site, F1- is bonded in a distorted single-bond geometry to three Cs1+ and one Pt2+ atom. In the sixth F1- site, F1- is bonded in a distorted single-bond geometry to four Cs1+ and one Pt2+ atom. In the seventh F1- site, F1- is bonded in a distorted single-bond geometry to three Cs1+ and one Pt2+ atom. In the eighth F1- site, F1- is bonded in a distorted single-bond geometry to four Cs1+ and one Pt2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsSn by Materials Project

CsSn crystallizes in the tetragonal I4_1/acd space group. The structure is three-dimensional. there are two inequivalent Cs sites. In the first Cs site, Cs is bonded in a 6-coordinate geometry to six equivalent Sn atoms. There are a spread of Cs–Sn bond distances ranging from 4.06–4.21 Å. In the second Cs site, Cs is bonded in a 12-coordinate geometry to eight equivalent Sn atoms. There are a spread of Cs–Sn bond distances ranging from 4.09–4.19 Å. Sn is bonded in a 10-coordinate geometry to seven Cs and three equivalent Sn atoms. There are one shorter (2.99 Å) and two longer (3.00 Å) Sn–Sn bond lengths.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cs4Li2(Si2O5)3 by Materials Project

Cs4Li2(Si2O5)3 crystallizes in the monoclinic P2_1/m space group. The structure is three-dimensional. there are eight inequivalent Cs1+ sites. In the first Cs1+ site, Cs1+ is bonded in a 2-coordinate geometry to eight O2- atoms. There are a spread of Cs–O bond distances ranging from 3.08–3.61 Å. In the second Cs1+ site, Cs1+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Cs–O bond distances ranging from 3.12–3.67 Å. In the third Cs1+ site, Cs1+ is bonded in a 10-coordinate geometry to ten O2- atoms. There are a spread of Cs–O bond distances ranging from 3.19–3.75 Å. In the fourth Cs1+ site, Cs1+ is bonded in a 5-coordinate geometry to four O2- atoms. There are two shorter (3.12 Å) and two longer (3.20 Å) Cs–O bond lengths. In the fifth Cs1+ site, Cs1+ is bonded in a 9-coordinate geometry to nine O2- atoms. There are a spread of Cs–O bond distances ranging from 3.20–3.42 Å. In the sixth Cs1+ site, Cs1+ is bonded in a 12-coordinate geometry to twelve O2- atoms. There are a spread of Cs–O bond distances ranging from 3.17–3.66 Å. In the seventh Cs1+ site, Cs1+ is bonded in a 11-coordinate geometry to eleven O2- atoms. There are a spread of Cs–O bond distances ranging from 3.19–3.56 Å. In the eighth Cs1+ site, Cs1+ is bonded in a 4-coordinate geometry to four O2- atoms. There are two shorter (3.06 Å) and two longer (3.23 Å) Cs–O bond lengths. There are two inequivalent Li1+ sites. In the first Li1+ site, Li1+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.87 Å) and two longer (1.88 Å) Li–O bond length. In the second Li1+ site, Li1+ is bonded in a trigonal planar geometry to three O2- atoms. There is one shorter (1.87 Å) and two longer (1.88 Å) Li–O bond length. There are six inequivalent Si4+ sites. In the first Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.59–1.66 Å. In the second Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.59–1.67 Å. In the third Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.59–1.67 Å. In the fourth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.58–1.67 Å. In the fifth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There is one shorter (1.59 Å) and three longer (1.66 Å) Si–O bond length. In the sixth Si4+ site, Si4+ is bonded to four O2- atoms to form corner-sharing SiO4 tetrahedra. There are a spread of Si–O bond distances ranging from 1.59–1.67 Å. There are eighteen inequivalent O2- sites. In the first O2- site, O2- is bonded in a linear geometry to one Cs1+ and two equivalent Si4+ atoms. In the second O2- site, O2- is bonded in a distorted bent 150 degrees geometry to four Cs1+, one Li1+, and one Si4+ atom. In the third O2- site, O2- is bonded in a distorted bent 150 degrees geometry to one Cs1+ and two Si4+ atoms. In the fourth O2- site, O2- is bonded in a linear geometry to two Cs1+ and two equivalent Si4+ atoms. In the fifth O2- site, O2- is bonded in a distorted linear geometry to four Cs1+, one Li1+, and one Si4+ atom. In the sixth O2- site, O2- is bonded in a distorted linear geometry to three Cs1+, one Li1+, and one Si4+ atom. In the seventh O2- site, O2- is bonded in a bent 150 degrees geometry to two Cs1+ and two Si4+ atoms. In the eighth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Cs1+ and two Si4+ atoms. In the ninth O2- site, O2- is bonded in a bent 150 degrees geometry to two Cs1+ and two Si4+ atoms. In the tenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Cs1+ and two Si4+ atoms. In the eleventh O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Cs1+, one Li1+, and one Si4+ atom. In the twelfth O2- site, O2- is bonded in a linear geometry to two Cs1+ and two equivalent Si4+ atoms. In the thirteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to three Cs1+, one Li1+, and one Si4+ atom. In the fourteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Cs1+, one Li1+, and one Si4+ atom. In the fifteenth O2- site, O2- is bonded in a distorted bent 150 degrees geometry to two Cs1+ and two Si4+ atoms. In the sixteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Cs1+ and two equivalent Si4+ atoms. In the seventeenth O2- site, O2- is bonded in a distorted linear geometry to one Cs1+ and two equivalent Si4+ atoms. In the eighteenth O2- site, O2- is bonded in a bent 150 degrees geometry to two Cs1+ and two equivalent Si4+ atoms.

36 MATERIALS SCIENCE↗