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34 records · Page 2
All sourcesNASA NTRSDOE OSTI
DOE OSTI2024

Mercury Detection Utilizing an Aquatic Animal as a Remote-Sensing Platform

Mercury species in open water, especially the accumulated methylmercury ion, pose a threat to fish and environment. Therefore, it is important to develop a small sensor package that can be integrated into a biotelemetry sensor carried by an aquatic animal, enhancing the ability to detect mercury contamination in large water areas. A quartz crystal microbalance (QCM) sensor using metal-organic framework (MOF) as sensing material was developed to detect mercury and methylmercury ions in real time based on acoustic wave perturbation. Thiol groups were introduced into the MOF UiO-66 through the organic linker to prepare the UiO-66-SH which was confirmed by infrared spectroscopy results. Batch adsorption experiments were conducted for the Hg 2+ , CH 3 Hg + , and Ca 2+ ions adsorption in the UiO-66-SH. The adsorption capacities of the mercury ions were more than an order of magnitude higher than those of the competing Ca 2+ ions at the same concentration. The frequency changes of the QCM sensor with the UiO-66-SH sensing film were an order of magnitude higher than those of the controlled baseline QCM sensor without a sensing film. Additionally, the frequency change can be tailored by adjusting the thickness of the MOF film and the adsorption properties of the sensing material. The sensor frequency change correlates well with ion adsorption capacities.

47 OTHER INSTRUMENTATION↗
DOE OSTI2020

Materials Data on RbHg(NO2)3 by Materials Project

Rb(NO2)3Hg crystallizes in the cubic Pm-3 space group. The structure is three-dimensional and consists of one mercury molecule and one Rb(NO2)3 framework. In the Rb(NO2)3 framework, Rb1+ is bonded to twelve equivalent O2- atoms to form edge-sharing RbO12 cuboctahedra. All Rb–O bond lengths are 3.55 Å. N3+ is bonded in a linear geometry to two equivalent O2- atoms. Both N–O bond lengths are 1.24 Å. O2- is bonded in a single-bond geometry to two equivalent Rb1+ and one N3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CsHg(NO2)3 by Materials Project

Cs(NO2)3Hg crystallizes in the cubic Pm-3 space group. The structure is three-dimensional and consists of one mercury molecule and one Cs(NO2)3 framework. In the Cs(NO2)3 framework, Cs1+ is bonded to twelve equivalent O2- atoms to form edge-sharing CsO12 cuboctahedra. All Cs–O bond lengths are 3.59 Å. N3+ is bonded in a linear geometry to two equivalent O2- atoms. Both N–O bond lengths are 1.24 Å. O2- is bonded in a single-bond geometry to two equivalent Cs1+ and one N3+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Hg15(As2Cl3)4 by Materials Project

Hg(Hg7(As2Cl3)2)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of two mercury molecules and one Hg7(As2Cl3)2 framework. In the Hg7(As2Cl3)2 framework, there are eight inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded to six Cl1- atoms to form edge-sharing HgCl6 octahedra. There are two shorter (2.75 Å) and four longer (2.76 Å) Hg–Cl bond lengths. In the second Hg2+ site, Hg2+ is bonded to six Cl1- atoms to form edge-sharing HgCl6 octahedra. All Hg–Cl bond lengths are 2.76 Å. In the third Hg2+ site, Hg2+ is bonded to two As+2.25- and four Cl1- atoms to form distorted HgAs2Cl4 octahedra that share corners with eight HgAs2Cl4 octahedra, corners with two AsHg3As tetrahedra, and edges with six HgCl6 octahedra. The corner-sharing octahedra tilt angles range from 16–88°. There are one shorter (2.56 Å) and one longer (2.57 Å) Hg–As bond lengths. There are a spread of Hg–Cl bond distances ranging from 3.01–3.40 Å. In the fourth Hg2+ site, Hg2+ is bonded to two As+2.25- and four Cl1- atoms to form distorted HgAs2Cl4 octahedra that share corners with eight HgAs2Cl4 octahedra, corners with two AsHg3As tetrahedra, and edges with six HgCl6 octahedra. The corner-sharing octahedra tilt angles range from 16–88°. There are one shorter (2.56 Å) and one longer (2.57 Å) Hg–As bond lengths. There are a spread of Hg–Cl bond distances ranging from 3.01–3.41 Å. In the fifth Hg2+ site, Hg2+ is bonded to two As+2.25- and four Cl1- atoms to form distorted HgAs2Cl4 octahedra that share corners with eight HgAs2Cl4 octahedra, corners with two AsHg3As tetrahedra, and edges with six HgAs2Cl4 octahedra. The corner-sharing octahedra tilt angles range from 16–88°. Both Hg–As bond lengths are 2.57 Å. There are a spread of Hg–Cl bond distances ranging from 3.01–3.41 Å. In the sixth Hg2+ site, Hg2+ is bonded to two As+2.25- and four Cl1- atoms to form distorted HgAs2Cl4 octahedra that share corners with eight HgAs2Cl4 octahedra, corners with two AsHg3As tetrahedra, and edges with six HgAs2Cl4 octahedra. The corner-sharing octahedra tilt angles range from 16–88°. Both Hg–As bond lengths are 2.56 Å. There are a spread of Hg–Cl bond distances ranging from 3.01–3.40 Å. In the seventh Hg2+ site, Hg2+ is bonded to two As+2.25- and four Cl1- atoms to form distorted HgAs2Cl4 octahedra that share corners with eight HgAs2Cl4 octahedra, corners with two AsHg3As tetrahedra, and edges with six HgCl6 octahedra. The corner-sharing octahedra tilt angles range from 16–88°. Both Hg–As bond lengths are 2.57 Å. There are a spread of Hg–Cl bond distances ranging from 3.01–3.41 Å. In the eighth Hg2+ site, Hg2+ is bonded to two As+2.25- and four Cl1- atoms to form distorted HgAs2Cl4 octahedra that share corners with eight HgAs2Cl4 octahedra, corners with two AsHg3As tetrahedra, and edges with six HgCl6 octahedra. The corner-sharing octahedra tilt angles range from 16–88°. There are one shorter (2.56 Å) and one longer (2.57 Å) Hg–As bond lengths. There are a spread of Hg–Cl bond distances ranging from 3.01–3.40 Å. There are four inequivalent As+2.25- sites. In the first As+2.25- site, As+2.25- is bonded to three Hg2+ and one As+2.25- atom to form AsHg3As tetrahedra that share corners with three HgAs2Cl4 octahedra, corners with four ClHg5 square pyramids, and corners with three AsHg3As tetrahedra. The corner-sharing octahedral tilt angles are 70°. The As–As bond length is 2.51 Å. In the second As+2.25- site, As+2.25- is bonded to three Hg2+ and one As+2.25- atom to form AsHg3As tetrahedra that share corners with three HgAs2Cl4 octahedra, corners with two ClHg5 square pyramids, corners with three AsHg3As tetrahedra, and an edgeedge with one ClHg5 square pyramid. The corner-sharing octahedral tilt angles are 74°. The As–As bond length is 2.51 Å. In the third As+2.25- site, As+2.25- is bonded to three Hg2+ and one As+2.25- atom to form AsHg3As tetrahedra that share corners with three HgAs2Cl4 octahedra, corners with four ClHg5 square pyramids, corners with three AsHg3As tetrahedra, and edges with two ClHg5 square pyramids. The corner-sharing octahedral tilt angles are 74°. In the fourth As+2.25- site, As+2.25- is bonded to three Hg2+ and one As+2.25- atom to form AsHg3As tetrahedra that share corners with three HgAs2Cl4 octahedra, corners with two ClHg5 square pyramids, corners with three AsHg3As tetrahedra, and edges with three ClHg5 square pyramids. The corner-sharing octahedral tilt angles are 70°. There are six inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 5-coordinate geometry to five Hg2+ atoms. In the second Cl1- site, Cl1- is bonded to five Hg2+ atoms to form distorted ClHg5 square pyramids that share corners with five ClHg5 square pyramids, corners with four AsHg3As tetrahedra, and edges with two AsHg3As tetrahedra. In the third Cl1- site, Cl1- is bonded in a 5-coordinate geometry to five Hg2+ atoms. In the fourth Cl1- site, Cl1- is bonded to five Hg2+ atoms to form distorted ClHg5 square pyramids that share corners with seven ClHg5 square pyramids, corners with four AsHg3As tetrahedra, edges with two equivalent ClHg5 square pyramids, and edges with two AsHg3As tetrahedra. In the fifth Cl1- site, Cl1- is bonded to five Hg2+ atoms to form distorted ClHg5 square pyramids that share corners with seven ClHg5 square pyramids, corners with four AsHg3As tetrahedra, edges with two equivalent ClHg5 square pyramids, and edges with two AsHg3As tetrahedra. In the sixth Cl1- site, Cl1- is bonded in a 5-coordinate geometry to five Hg2+ atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on Cd2Hg13(As2Cl3)4 by Materials Project

Hg(Hg6Cd(As2Cl3)2)2 crystallizes in the monoclinic P2_1/c space group. The structure is three-dimensional and consists of two mercury molecules and one Hg6Cd(As2Cl3)2 framework. In the Hg6Cd(As2Cl3)2 framework, there are six inequivalent Hg2+ sites. In the first Hg2+ site, Hg2+ is bonded to two As+2.25- and four Cl1- atoms to form distorted HgAs2Cl4 octahedra that share corners with eight HgAs2Cl4 octahedra, corners with two AsHg3As tetrahedra, edges with two CdCl6 octahedra, and edges with four HgAs2Cl4 octahedra. The corner-sharing octahedra tilt angles range from 18–89°. Both Hg–As bond lengths are 2.56 Å. There are a spread of Hg–Cl bond distances ranging from 3.03–3.41 Å. In the second Hg2+ site, Hg2+ is bonded to two As+2.25- and four Cl1- atoms to form distorted HgAs2Cl4 octahedra that share corners with eight HgAs2Cl4 octahedra, corners with two AsHg3As tetrahedra, edges with two CdCl6 octahedra, and edges with four HgAs2Cl4 octahedra. The corner-sharing octahedra tilt angles range from 18–89°. There are one shorter (2.56 Å) and one longer (2.57 Å) Hg–As bond lengths. There are a spread of Hg–Cl bond distances ranging from 3.02–3.40 Å. In the third Hg2+ site, Hg2+ is bonded to two As+2.25- and four Cl1- atoms to form distorted HgAs2Cl4 octahedra that share corners with eight HgAs2Cl4 octahedra, corners with two AsHg3As tetrahedra, edges with two equivalent CdCl6 octahedra, and edges with four HgAs2Cl4 octahedra. The corner-sharing octahedra tilt angles range from 18–89°. There are one shorter (2.56 Å) and one longer (2.57 Å) Hg–As bond lengths. There are a spread of Hg–Cl bond distances ranging from 3.02–3.41 Å. In the fourth Hg2+ site, Hg2+ is bonded to two As+2.25- and four Cl1- atoms to form distorted HgAs2Cl4 octahedra that share corners with eight HgAs2Cl4 octahedra, corners with two AsHg3As tetrahedra, edges with two equivalent CdCl6 octahedra, and edges with four HgAs2Cl4 octahedra. The corner-sharing octahedra tilt angles range from 18–89°. Both Hg–As bond lengths are 2.56 Å. There are a spread of Hg–Cl bond distances ranging from 3.02–3.41 Å. In the fifth Hg2+ site, Hg2+ is bonded to two As+2.25- and four Cl1- atoms to form distorted HgAs2Cl4 octahedra that share corners with eight HgAs2Cl4 octahedra, corners with two AsHg3As tetrahedra, edges with two CdCl6 octahedra, and edges with four HgAs2Cl4 octahedra. The corner-sharing octahedra tilt angles range from 18–89°. There are one shorter (2.56 Å) and one longer (2.57 Å) Hg–As bond lengths. There are a spread of Hg–Cl bond distances ranging from 3.03–3.40 Å. In the sixth Hg2+ site, Hg2+ is bonded to two As+2.25- and four Cl1- atoms to form distorted HgAs2Cl4 octahedra that share corners with eight HgAs2Cl4 octahedra, corners with two AsHg3As tetrahedra, edges with two CdCl6 octahedra, and edges with four HgAs2Cl4 octahedra. The corner-sharing octahedra tilt angles range from 18–89°. There are one shorter (2.56 Å) and one longer (2.57 Å) Hg–As bond lengths. There are a spread of Hg–Cl bond distances ranging from 3.02–3.41 Å. There are two inequivalent Cd2+ sites. In the first Cd2+ site, Cd2+ is bonded to six Cl1- atoms to form CdCl6 octahedra that share edges with twelve HgAs2Cl4 octahedra. All Cd–Cl bond lengths are 2.70 Å. In the second Cd2+ site, Cd2+ is bonded to six Cl1- atoms to form CdCl6 octahedra that share edges with twelve HgAs2Cl4 octahedra. There are two shorter (2.69 Å) and four longer (2.70 Å) Cd–Cl bond lengths. There are four inequivalent As+2.25- sites. In the first As+2.25- site, As+2.25- is bonded to three Hg2+ and one As+2.25- atom to form AsHg3As tetrahedra that share corners with three HgAs2Cl4 octahedra and corners with three AsHg3As tetrahedra. The corner-sharing octahedral tilt angles are 70°. The As–As bond length is 2.50 Å. In the second As+2.25- site, As+2.25- is bonded to three Hg2+ and one As+2.25- atom to form AsHg3As tetrahedra that share corners with three HgAs2Cl4 octahedra and corners with three AsHg3As tetrahedra. The corner-sharing octahedral tilt angles are 74°. The As–As bond length is 2.51 Å. In the third As+2.25- site, As+2.25- is bonded to three Hg2+ and one As+2.25- atom to form AsHg3As tetrahedra that share corners with three HgAs2Cl4 octahedra and corners with three AsHg3As tetrahedra. The corner-sharing octahedral tilt angles are 74°. In the fourth As+2.25- site, As+2.25- is bonded to three Hg2+ and one As+2.25- atom to form AsHg3As tetrahedra that share corners with three HgAs2Cl4 octahedra and corners with three AsHg3As tetrahedra. The corner-sharing octahedral tilt angles are 70°. There are six inequivalent Cl1- sites. In the first Cl1- site, Cl1- is bonded in a 5-coordinate geometry to four Hg2+ and one Cd2+ atom. In the second Cl1- site, Cl1- is bonded in a 5-coordinate geometry to four Hg2+ and one Cd2+ atom. In the third Cl1- site, Cl1- is bonded in a 5-coordinate geometry to four Hg2+ and one Cd2+ atom. In the fourth Cl1- site, Cl1- is bonded in a 5-coordinate geometry to four Hg2+ and one Cd2+ atom. In the fifth Cl1- site, Cl1- is bonded in a 5-coordinate geometry to four Hg2+ and one Cd2+ atom. In the sixth Cl1- site, Cl1- is bonded in a 5-coordinate geometry to four Hg2+ and one Cd2+ atom.

36 MATERIALS SCIENCE↗
DOE OSTI2020

Materials Data on CaHg(IO2)4 by Materials Project

Ca(O2I)4Hg crystallizes in the tetragonal P4_2/mbc space group. The structure is three-dimensional and consists of eight mercury molecules and one Ca(O2I)4 framework. In the Ca(O2I)4 framework, there are two inequivalent Ca sites. In the first Ca site, Ca is bonded in a 8-coordinate geometry to eight O atoms. There are four shorter (2.44 Å) and four longer (2.53 Å) Ca–O bond lengths. In the second Ca site, Ca is bonded in a 8-coordinate geometry to eight O atoms. There are four shorter (2.51 Å) and four longer (2.69 Å) Ca–O bond lengths. There are four inequivalent O sites. In the first O site, O is bonded in a bent 120 degrees geometry to one Ca and one I atom. The O–I bond length is 1.83 Å. In the second O site, O is bonded in a distorted trigonal planar geometry to one Ca and two I atoms. There are one shorter (1.89 Å) and one longer (2.52 Å) O–I bond lengths. In the third O site, O is bonded in a bent 120 degrees geometry to one Ca and one I atom. The O–I bond length is 1.89 Å. In the fourth O site, O is bonded in a bent 120 degrees geometry to one Ca and one I atom. The O–I bond length is 1.84 Å. There are three inequivalent I sites. In the first I site, I is bonded in a water-like geometry to two equivalent O atoms. In the second I site, I is bonded in a water-like geometry to two equivalent O atoms. In the third I site, I is bonded in a distorted water-like geometry to three O atoms.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Maternal provisioning interacts with incubation temperature to affect hatchling mercury exposure in an oviparous reptile

The thermal environment experienced by developing embryos can influence the utilization of maternally provisioned resources. Despite being particularly consequential for oviparous ectotherms, these dynamics are largely unexplored within ecotoxicological frameworks. Here, we test if incubation temperature interacts with maternally transferred mercury to affect subsequent body burdens and tissue distributions of mercury in hatchling American alligators (Alligator mississippiensis). Nine clutches of alligator eggs were collected from a mercury-contaminated reservoir and incubated at either female- or male-promoting temperatures. Total mercury (THg) concentration was measured in egg yolk collected during incubation and in a suite of tissues collected from hatchlings. THg concentrations in residual yolk and blood were higher in hatchlings incubated at cooler, female-promoting temperatures compared to the warmer, male-promoting temperatures. THg concentrations in most tissues were positively correlated with THg concentrations in blood and dermis, and egg yolk THg concentration was the best predictor of THg concentration in many resultant tissues. Furthermore, our results highlight a hereto unknown role of the developmental environment in mediating tissue specific uptake of contaminants in an oviparous reptile.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Novel Remediation of Mercury-Contaminated Sediments Using Manganese Oxide and Activated Carbon Amendments - 20394

Mercury contamination in sediments poses a challenging remediation problem because of its ability to biogeochemically cycle and biomagnify in the food chain as methylmercury from low resident sediment and porewater concentrations. One mitigation approach is to lower the overall rate of net methylmercury production by creating conditions unfavorable for sulfate and iron reduction or methanogenesis, the primary pathways for methylation of inorganic mercury. Manganese oxides and other redox-active amendments are a promising and novel in situ amendment technology aimed at reducing net methylation of mercury though control of redox conditions in mercury-contaminated sediment-water systems. This paper reviews the thermodynamic and kinetic framework for this remediation technology, presents experimental and spectroscopic data illustrating the approach using solid manganese oxides, and discusses potential advantages, disadvantages, and applications. (authors)

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2022

Interfacial interactions between polymers and selective adsorbents influence ion transport properties of boron scavenging ion-exchange membranes

The recent emergence of adsorptive ion-exchange membranes (IEMs), designed by the synergistic integration of highly selective porous aromatic frameworks (PAFs) with ion-exchange polymers, has enabled simultaneous desalination and targeted removal of specific solutes (e.g., mercury, iron, boron, etc.). While the addition of highly selective PAFs to IEMs yields membranes with entirely new functions, PAF-polymer interactions, and the effects of such interactions on ion transport properties of the membranes, are not well understood. In this study, we developed cross-linked adsorptive cation- and anion-exchange membranes (CEMs and AEMs) for simultaneous desalination and boron removal via in-situ formation of the cross-linked polymer network around the boron selective PAF particles. Here we systematically investigated the influence of PAF loading level on PAF-polymer interactions as well as the equilibrium and transport properties of the adsorptive IEMs. The interactions between the PAF and the ion-exchange polymer matrix differed for the CEMs and AEMs due to differences in the fixed charge group chemistry. Notably, the sulfonate groups of the CEMs can form hydrogen bonds with the hydroxyl groups of the PAF, while the quaternary ammonium groups in the AEMs cannot. These differences in interfacial interactions did not significantly impact counter-ion transport across the adsorptive IEMs but had a significant influence on co-ion transport, which affected the counter-ion/co-ion selectivity of the membranes. The selectivity of the adsorptive CEMs decreased while that of the adsorptive AEMs increased with PAF loading level. The results of this study underscore the importance of controlling interfacial interactions when designing adsorptive IEMs for simultaneous water desalination and solute capture and recovery.

36 MATERIALS SCIENCE↗
DOE OSTI2022

Benchmarking and Exploring Parameter Space of the 2-Phase Bubble Tracking Model for Liquid Mercury Target Simulation

High intensity proton pulses strike the Spallation Neutron Source (SNS)’s mercury target to provide bright neutron beams. These strikes deposit extensive energy into the mercury and its steel vessel. Prediction of the resultant loading on the target is difficult when helium gas is intentionally injected into the mercury to reduce the loading and to mitigate the pitting damage on the vessel. A 2-phase material model that incorporates the Rayleigh-Plesset (R-P) model is expected to address this complex multi-physics dynamics problem by including the bubble dynamics in the liquid mercury. We present a study comparing the measured target strains in the SNS target station with the simulation results of the solid mechanics simulation framework. We investigate a wide range of various physical model parameters, including the number of bubble families, bubble size distribution, viscosity, surface tension, etc. to understand their impact on simulation accuracy. Our initial findings reveal that using 8-10 bubble families in the model renders a simulation strain envelope that covers the experimental ones. Further optimization studies are planned to predict the strain response more accurately.

Lin, Lianshan↗
DOE OSTI2021

Determination of Arsenic Content in Water Using a Silver Coordination Polymer

In this report, we describe a practical method for the colorimetric determination of dissolved inorganic arsenic content in water samples, using a silver coordination polymer as the sensing material. We demonstrate that a crystalline polymer framework can be used to stabilize silver(I) ions, greatly reducing both photosensitivity and water solubility, while still affording sufficient reactivity to detect arsenic in water samples at low parts-per-billion (ppb) levels. Test strips fabricated with the silver-based polymer are shown to be effective for field tests of groundwater under real-world operating conditions and display performance that is competitive with commercially available mercury-based test strips. Spectroscopic methods are also used to probe the reaction products formed, in order to better understand the sensing mechanism. Thus, our work provides the foundation for an improved field test that could be deployed to help manage groundwater usage in regions where arsenic contamination is problematic but sophisticated lab testing is not readily available.

36 MATERIALS SCIENCE↗
DOE OSTI2024

Calibration of the 2-Phase Bubble Tracking Model for Liquid Mercury Target Simulation with Machine Learning Surrogate Models

The Spallation Neutron Source (SNS) at Oak Ridge National Laboratory is one of the most powerful accelerator-driven neutron sources in the world. The intense protons strike on SNS's mercury target to provide bright neutron beams, which also leads to severe fluid-structure interactions inside the target. Prediction of resultant loading on the target is difficult particularly when helium gas is injected into mercury to reduce the loading and mitigate the pitting damage on vessel walls. A 2-phase material model that incorporates the Rayleigh-Plesset (R-P) model is expected to address this multi-physics problem. However, several uncertain parameters in the R-P model require intensive simulations to determine their optimal values. With the help of machine learning and the measured target strain, we have studied the major uncertain parameters in this R-P model and developed a framework to identify optimal parameters that significantly reduce the discrepancy between simulations and experimental strains. The preliminary results show the possibility of using this mercury/helium mixture and surrogate models to predict a better match of target strain response when the helium gas is injected.

Lin, Lianshan↗
DOE OSTI2023

Sample Size Effects on Petrophysical Characterization and Fluid-to-Pore Accessibility of Natural Rocks

Laboratory-scale analysis of natural rocks provides petrophysical properties such as density, porosity, pore diameter/pore-throat diameter distribution, and fluid accessibility, in addition to the size and shape of framework grains and their contact relationship with the rock matrix. Different types of laboratory approaches for petrophysical characterization involve the use of a range of sample sizes. While the sample sizes selected should aim to be representative of the rock body, there are inherent limitations imposed by the analytical principles and holding capacities of the different experimental apparatuses, with many instruments only able to accept samples at the μm–mm scale. Therefore, a total of nine (three limestones, three shales, two sandstones, and one dolomite) samples were collected from Texas to fill the knowledge gap of the sample size effect on the resultant petrophysical characteristics. The sample sizes ranged from 3 cm cubes to <75 μm particles. Using a combination of petrographic microscopy, helium expansion pycnometry, water immersion porosimetry, mercury intrusion porosimetry, and (ultra-) small-angle X-ray scattering, the impact of sample size on the petrophysical properties of these samples was systematically investigated here. The results suggest that the sample size effect is influenced by both pore structure changes during crushing and sample size-dependent fluid-to-pore connectivity.

36 MATERIALS SCIENCE↗
DOE OSTI2023

HIGH-LOW FIDELITY THERMAL HYDRAULIC COUPLING USING AI/MACHINE LEARNING ALGORITHMS

The primary goal of the US Department of Energy (DOE) office of Nuclear Energy Integrated Energy Systems (IES) program is to develop the tools and framework for coupling multi-scale and multi-physical thermal and electrical energy usage and storage systems. High- and low-fidelity (high–low) coupling is a key feature of multi-scale, multi-component systems and has been an important focus of research in the nuclear energy community for the past two decades. An essential feature of demonstrating the capability to couple high-fidelity and low-fidelity systems for real-time applications are surrogate/reduced order models (ROM). For the purposes of this study, surrogate models are essentially Blackbox models, typically developed using supervised Machine learning (ML) algorithms. The surrogate models can be used to mimic the response of high-fidelity models to represent large historical datasets and coupled with more general low-fidelity system models distributed as Functional Mock-up Interface (FMI) or Functional Mock-up Units (FMU) modules. The example is demonstrated with Spallation Neutron Source (SNS) First Target Station flow loop data. The flow loop is a liquid mercury loop with a pump, piping, heat exchange, and internal heat generation in the target window. This work elucidates some of the potential benefits and future needs of developing tools for high–low system coupling of energy systems.

Williams, Wesley↗
DOE OSTI2023

Toggling Stereochemical Activity through Interstitial Positioning of Cations between 2D V 2 O 5 Double Layers

The 5/6s 2 lone-pair electrons of p-block cations in their lower oxidation states are a versatile electronic and geometric structure motif that can underpin lattice anharmonicity and often engender electronic and structural instabilities that underpin the function of active elements in nonlinear optics, thermochromics, thermoelectrics, neuromorphic computing, and photocatalysis. In contrast to periodic solids where lone-pair-bearing cations are part of the structural framework, installing lone-pair-bearing cations in the interstitial sites of intercalation hosts provides a means of a systematically modulating electronic structure through the choice of the group and the period of the inserted cation while preserving the overall framework connectivity. The extent of stereochemical activity and the energy positioning of lone-pair-derived mid-gap states depend on the cation identity, stoichiometry, and strength of anion hybridization. V 2 O 5 polymorphs are versatile insertion hosts that can accommodate a broad range of s-, p-, and d-block cations. However, the insertion of lone-pair-bearing cations remains largely underexplored. In this article, we examine the implications of varying the 6s 2 cations situated in interlayer sites between condensed [V 4 O 10 ] n double layers. Systematic modulations of lattice distortions, electronic structure, and magnetic ordering are observed with increasing strength of stereochemical activity from group 12 to group 14 cations. We compare and contrast p-block-layered M x V 2 O 5 (M = Hg, Tl, and Pb) compounds and map the significance of local off-centering arising from the stereochemical activity of lone-pair cations to the emergence of filled antibonding lone-pair 6s 2 –O 2p-hybridized mid-gap states mediated by second-order Jahn–Teller distortions. Crystallographic studies of cation coordination environments and the resulting modulation of V–V interactions have been used in conjunction with variable-energy hard X-ray photoelectron spectroscopy measurements, first-principles electronic structure calculations, and crystal orbital Hamilton population analyses to decipher the origins of stereochemical activity. Magnetic susceptibility measurements reveal antiferromagnetic signatures for all the three compounds. However, the differences in V–V interactions significantly affect the energy balance of the superexchange interactions, resulting in an ordering temperature of 160 and 260 K for Hg 0.5 V 2 O 5 and δ-Tl 0.5 V 2 O 5 , respectively, as compared to 7 K for δ-Pb 0.5 V 2 O 5 . In δ-Pb 0.5 V 2 O 5 , the strong stereochemical activity of electron lone pairs and the resulting electrostatic repulsions enforce superlattice ordering, which strongly modifies the electronic localization patterns along the [V 4 O 10 ] slabs, resulting in disrupted magnetic ordering and an anomalously low ordering temperature. The results demonstrate a versatile strategy for toggling the stereochemical activity of electron lone pairs to modify the electronic structure near the Fermi level and to mediate superexchange interactions.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗