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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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All sourcesNASA NTRSDOE OSTI
NASA NTRS1978

Mercury - Magnetic field and interior

Present-day knowledge about the planetary magnetic field and interior of Mercury is reviewed. Radar observations are discussed which delineated the correct rotation rate of Mercury (58.646 days) and the planet's 3:2 spin-orbit resonance. The data obtained in Mariner 10 magnetic-field observations during the first and third encounters with Mercury are examined in detail, and theoretical studies of the planet's interior are summarized, including both steady-state models and those describing the thermal evolution of the planet. Two possible source mechanisms for the observed intrinsic planetary magnetic field are evaluated: an active dynamo and a passive paleomagnetic field frozen into the planet's outer layers at an earlier epoch. It is noted that neither the available magnetic-field data nor models of the planetary interior permit one to distinguish uniquely between the two mechanisms. The spin-orbit commensurability of Mercury is explained in the framework of the solar tides induced in the body of the planet, a nonaxisymmetric moment of inertia, and the highly eccentric orbit of the planet.

Ness, N. F.↗
DOE OSTI2020

Expanded Phylogenetic Diversity and Metabolic Flexibility of Mercury-Methylating Microorganisms

Methylmercury is a potent bioaccumulating neurotoxin that is produced by specific microorganisms that methylate inorganic mercury. Methylmercury production in diverse anaerobic bacteria and archaea was recently linked to the hgcAB genes. However, the full phylogenetic and metabolic diversity of mercury-methylating microorganisms has not been fully unraveled due to the limited number of cultured experimentally verified methylators and the limitations of primer-based molecular methods. Here, we describe the phylogenetic diversity and metabolic flexibility of putative mercury-methylating microorganisms by hgcAB identification in publicly available isolate genomes and metagenome-assembled genomes (MAGs) as well as novel freshwater MAGs. We demonstrate that putative mercury methylators are much more phylogenetically diverse than previously known and that hgcAB distribution among genomes is most likely due to several independent horizontal gene transfer events. The microorganisms we identified possess diverse metabolic capabilities spanning carbon fixation, sulfate reduction, nitrogen fixation, and metal resistance pathways. We identified 111 putative mercury methylators in a set of previously published permafrost metatranscriptomes and demonstrated that different methylating taxa may contribute to hgcA expression at different depths. Overall, we provide a framework for illuminating the microbial basis of mercury methylation using genome-resolved metagenomics and metatranscriptomics to identify putative methylators based upon hgcAB presence and describe their putative functions in the environment.

59 BASIC BIOLOGICAL SCIENCES↗
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↗
NASA NTRS1988

Mercury's magnetic field and interior

The magnetic-field data collected on Mercury by the Mariner-10 spacecraft present substantial evidence for an intrinsic global magnetic field. However, studies of Mercury's thermal evolution show that it is most likely that the inner core region of Mercury solidified or froze early in the planet's history. Thus, the explanation of Mercury's magnetic field in the framework of the traditional planetary dynamo is less than certain.

Connerney, J. E. P.↗
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↗
NASA NTRS2019

The Rate of Surface Evolution on the Moon and Mercury

We are converging on a model for how the topography of airless bodies evolves, including process and rate. This understanding provides a framework for constraining the age of individual craters, features, and surfaces. Landform evolution was much faster on Mercury than the Moon. This may have important consequences for understanding early Mercury history.

Fassett, Caleb↗
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↗
NASA NTRS1981

Application of ring tectonic theory to Mercury and other solar system bodies

It is pointed out that multiringed structures, by their presence or absence, provide a powerful tool for deciphering the thermal histories of the solid planets. The theory of ring tectonics considered by Melosh and McKinnon (1978) and Melosh et al. (1980) establishes the framework of that undertaking. The present investigation has the objective to apply this conceptualization in detail to the multiringed basins on Mercury, taking into account also a brief review concerning the current state of understanding of ring tectonics on the moon, Mars, earth, Ganymede, and Callisto. The small, icy satellites of Saturn are also discussed. The mechanics of multiple ring formation are related to the collapse of the transient basin cavity when the excavation depth and lithosphere thickness are comparable. Attention is given to the Caloris Basin on Mercury, the peak ring basins on Mercury, and the Argyre Basin on Mars.

Mckinnon, W. B.↗
NASA NTRS1977

Mercury

Information about Mercury obtained with the Mariner 10 spacecraft is summarized together with results of theoretical studies and ground-based observations. It is shown that Mercury is very likely a differentiated body, probably contains a large earthlike iron-rich core, and displays a surface similar to the moon's, which suggests a similar evolutionary history. The size and mass of Mercury are discussed along with its orbit, rotation, atmosphere, magnetic field, and magnetosphere. Surface features of Mercury are described on the basis of Mariner 10 pictures, with detailed attention given to the major physiographic provinces, the structure of the Caloris basin, the tectonic framework of the planet, crater morphology, the planet's optical and thermal properties, and cartography. The composition and structure of the interior are examined, and the thermal history of Mercury is considered. The planet's geologic history is divided into five stages or epochs: (1) accretion and differentiation, (2) terminal heavy bombardment, (3) Caloris basin formation, (4) basin flooding, and (5) postfilling lighter bombardment.

Gault, D. E.↗
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↗
NASA NTRS2020

Mercury Lander: Transformative Science from the Surface of the Innermost Planet

As an end-member of terrestrial planet formation, Mercury holds unique clues about the original distribution of elements in the earliest stages of solar system development and how planets and exoplanets form and evolve in close proximity to their host stars. This Mercury Lander mission concept enables in situ surface measurements that address several fundamental science questions raised by MESSENGER’s pioneering exploration of Mercury. Such measurements are needed to understand Mercury’s unique mineralogy and geochemistry; to characterize the proportionally massive core’s structure; to measure the planet’s active and ancient magnetic fields at the surface; to investigate the processes that alter the surface and produce the exosphere; and to provide ground truth for current and future remote datasets. NASA’s Planetary Mission Concept Studies (PMCS) program awarded this study to a multidisciplinary team led by Dr. Carolyn Ernst of the Johns Hopkins Applied Physics Laboratory (APL), to evaluate the feasibility of accomplishing transformative science through a New-Frontiers-class, landed mission to Mercury in the next decade. The resulting mission concept achieves one full Mercury year (~88 Earth days) of surface operations with an ambitious, high-heritage, landed science payload, corresponding well with the New Frontiers mission framework.

Mercury lander↗
NASA NTRS2005

Motion of the Mantle in the Translational Modes of the Earth and Mercury

Slichter modes refer to the translational motion of the inner core with respect to the outer core and the mantle. The polar Slichter mode is the motion of the inner core along the axis of rotation. Busse presented an analysis of the polar mode which yielded an expression for its period. Busse's analysis included the assumption that the mantle was stationary. This approximation is valid for planets with small inner cores, such as the Earth whose inner core is about 1/60 of the total planet mass. On the other hand, many believe that Mercury's core may be enormous. If so, the motion of the mantle should be expected to produce a significant effect. We present a formal framework for including the motion of the mantle in the analysis of the translational motion of the inner core. We analyze the effect of the motion of the mantle on the Slichter modes for a non-rotating planet with an inner core of arbitrary size. We omit the effects of viscosity in the outer core, magnetic effects, and solid tides. Our approach is perturbative and is based on a linearization of Euler's equations for the motion of the fluid and Newton's second law for the motion of the inner core. We find an analytical expression for the period of the Slichter mode. Our result agrees with Busse's in the limiting case of small inner core. We present the unexpected result that even for Mercury the motion of the mantle does not significantly change the period of oscillation.

Grinfeld, Pavel↗