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Comet C2012 S1 (ISON): Observations of the Dust Grains From SOFIA and of the Atomic Gas From NSO Dunn and Mcmath-Pierce Solar Telescopes

Comet C/2012 S1 (ISON) is unique in that it is a dynamically new comet derived from the Oort cloud reservoir of comets with a sun-grazing orbit. Infrared (IR) and visible wavelength observing campaigns were planned on NASA's Stratospheric Observatory For Infrared Astronomy (SOFIA) and on National Solar Observatory Dunn (DST) and McMath-Pierce Solar Telescopes, respectively. We highlight our SOFIA (+FORCAST) mid- to far-IR images and spectroscopy (approx. 5-35 microns) of the dust in the coma of ISON are to be obtained by the ISON-SOFIA Team during a flight window 2013 Oct 21-23 UT (r_h approx. = 1.18 AU). Dust characteristics, identified through the 10 micron silicate emission feature and its strength, as well as spectral features from cometary crystalline silicates (Forsterite) at 11.05-11.2 microns, and near 16, 19, 23.5, 27.5, and 33 microns are compared with other Oort cloud comets that span the range of small and/or highly porous grains (e.g., C/1995 O1 (Hale-Bopp) and C/2001 Q4 (NEAT) to large and/or compact grains (e.g., C/2007 N4 (Lulin) and C/2006 P1 (McNaught)). Measurement of the crystalline peaks in contrast to the broad 10 and 20 micron amorphous silicate features yields the cometary silicate crystalline mass fraction, which is a benchmark for radial transport in our protoplanetary disk. The central wavelength positions, relative intensities, and feature asymmetries for the crystalline peaks may constrain the shapes of the crystals. Only SOFIA can look for cometary organics in the 5-8 micron region. Spatially resolved measurements of atoms and simple molecules from when comet ISON is near the Sun (r_h< 0.4 AU, near Nov-20-Dec-03 UT) were proposed for by the ISON-DST Team. Comet ISON is the first comet since comet Ikeya-Seki (1965f) suitable for studying the alkalai metals Na and K and the atoms specifically attributed to dust grains including Mg, Si, Fe, as well as Ca. DST's Horizontal Grating Spectrometer (HGS) measures 4 settings: Na I, K, C2 to sample cometary organics (along with Mg I), and [OI] as a proxy for activity from water (along with Si I and Fe I). State-of-the-art instruments that will also be employed include IBIS, which is a Fabry-Perot spectral imaging system that concurrently measures lines of Na, K, Ca II, or Fe, and ROSA (CSUN/QUB), which is a rapid imager that simultaneously monitors Ca II or CN. From McMath-Pierce, the Solar-Stellar Spectrograph also will target ISON (320-900 nm, R approx. 21,000, r_h<0.3 AU). Assuming survival, the intent is to target ISON over r_h<0.4 AU, characteristic of prior Na detections.

Oort cloud comets↗

Physical, Chemical, and Petrological Characteristics of Chondritic Materials and Their Relationships to Small Solar System Bodies: Chapter - 2

Chondrite materials with varying abundances of volatile-bearing phases are expected at the destinations for the asteroid sample-return missions Hayabusa2 and OSIRIS-REx. The targets of the missions are 162173 (1999 JU3) Ryugu and 101955 (1999 RQ36) Bennu. Spectroscopic analyses of these asteroids suggest that their surface materials are related to types 1 and 2 carbonaceous chondrites. Some studies suggest that the parent bodies of these chondrites may have also experienced some thermal and/or shock metamorphism. The physical properties of boulders at asteroid surfaces and fine particles in asteroid regoliths are consequences of the diverse processes that fragmented them, mobilized them, and redeposited them in unique accumulations. Sample-return missions are likely to encounter a broad range of carbonaceous chondrite (CC)-like materials, to which aqueous alteration, thermal, and shock metamorphism imparted changes affecting their sub-micron- to meter-scale physical properties. Consequently, implementation of scale-dependent analytical techniques to the study of the chemical, physical, and geotechnical characteristics of these CC-like materials is fundamental to safe mission operations, sample selection, and return. However, most of the available knowledge for informing and formulating expectations about regolith processes, products, and properties on carbonaceous small bodies comes from missions that studied anhydrous (e.g., Itokawa studied by Hayabusa) and/or much larger asteroids (e.g., Vesta studied by Dawn). No previous mission is likely directly relevant to small ice-free carbonaceous NEOs 162173 Ryugu or 101955 Bennu, although the Rosetta Spaceraft performed a flyby of the large asteroid Lutetia which has variously been classified as M and C type (Pätzold et al., 2011). Carbonaceous chondrites carry the best record of the history, distribution, and activity of water in the early solar system. Ordinary and Enstatite chondrites carry only partial records, but these are still critical to understanding the full story. We will describe the records of water-rock interactions on asteroids, as recorded in these meteorites, with particular emphasis on the timing, nature, settings, and fluid compositions. An integral part of this story is the rare, but fortunate, preservation of actual early solar system water as aqueous fluid inclusions.

Zolensky, Michael E.↗

Merging Analytic Collaborative Frameworks with New Observing Strategies Toward a Digital Twin: Earth – Episodic Pulse Event Impacts on Ocean Carbon Cycle as an Example

Virtual representations of the Earth will allow us to address some of the most critical environmental issues of our time. Here, we show the first steps toward representation of riverine, estuarine, and coastal carbon processes to enable scenario driven “what-if” analyses of the carbon system and human footprint. Excess sediment and nutrient runoff from land-based human activities impact water quality and can pose serious threats to coastal and marine ecosystems. Episodic pulse events, such as extreme precipitation events, can increase the amount of nutrients entering estuaries and coastal regions, potentially leading to large phytoplankton blooms followed by anoxic conditions. Consequences of coastal runoff are predicted to increase with the higher intensity and frequency of extreme events. Beyond the threat to coastal ecosystems, recent findings suggest these episodic pulses might play a significant role for biological production influencing regional and global carbon fluxes and budgets. An improved understanding of these events through optimal, dynamic observing strategies will increase our knowledge of the land-ocean continuum and how regional events and nutrient fluxes affect the carbon cycle and ocean ecosystem. This conceptual framework enables focused science investigations by pairing data analytics and artificial intelligence tools (otherwise termed an Analytic Center Framework, ACF) with targeted measurement acquisition through distributed sensing and intelligent asset tasking (or New Observing Strategies, NOS). This NOS and ACF iterative approach acquires and integrates complementary and coincident satellite, in-situ and model data to build a more complete and in-depth picture of science phenomena. Specifically, Apache Science Data Analytic Platform (SDAP) is extended to incorporate relevant datasets for data access, harmonized analysis, and anomaly detection. When conditions are met for a likely pulse event, NASA’s D-SHIELD (Distributed Spacecraft with Heuristic Intelligence to Enable Logistical Decisions) tool is triggered to optimize asset overpass frequency and schedule observations for persistent monitoring. Targeted data is ingested by SDAP for enhanced investigation via iterative analysis until the trigger criteria is no longer met - steps toward a digital twin.

Laura Rogers↗

Modeling Initial Stage of Ablation Material Pyrolysis: Graphitic Precursor Formation and Interfacial Effects

Reactive molecular dynamics simulations are used to study initial stage of pyrolysis of ablation materials and their composites with carbon nanotubes and carbon fibers. The products formed during pyrolysis are characterized and water is found as the primary product in all cases. The water formation mechanisms are analyzed and the value of the activation energy for water formation is estimated. A detailed study on graphitic precursor formation reveals the presence of two temperature zones. In the lower temperature zone (less than 2000 K) polymerization occurs resulting in formation of large, stable graphitic precursors, and in the high temperature zone (greater than 2000 K) polymer scission results in formation of short polymer chains/molecules. Simulations performed in the high temperature zone on the phenolic resin composites (with carbon nanotubes and carbon fibers) shows that the presence of interfaces had no substantial effect on the chain scission rate or the activation energy value for water formation.

Desai, Tapan G.↗

Y-12 Groundwater Protection Program Groundwater and Surface Water Sampling and Analysis Plan (CY 2021)

This plan provides a description of the groundwater and surface water quality monitoring activities planned for calendar year (CY) 2021 at the U.S. Department of Energy Y-12 National Security Complex (Y-12) that will be managed by the Y-12 Groundwater Protection Program (GWPP). Groundwater and surface water monitoring is performed by the GWPP. Groundwater and surface water monitoring will be performed in three hydrogeologic regimes at Y-12: the Bear Creek Hydrogeologic Regime (Bear Creek Regime), the Upper East Fork Poplar Creek Hydrogeologic Regime (East Fork Regime), and the Chestnut Ridge Hydrogeologic Regime (Chestnut Ridge Regime). The Bear Creek and East Fork regimes are located in Bear Creek Valley and the Chestnut Ridge Regime is located south of Y-12. Additional surface water monitoring will be performed north of Pine Ridge along the boundary of the Oak Ridge Reservation. The following sections of this report provide details regarding the CY 2021 groundwater and surface water monitoring activities. Section 2 describes the monitoring locations in each regime and the processes used to select the sampling locations. A description of the field measurements and laboratory analytes is provided in Section 3. Sample collection methods and procedures are described in Section 4, and Section 5 lists the documents cited for more detailed operational and technical information. The narrative sections of the report reference several appendices. Figures (maps and diagrams) and tables (excluding a data summary table presented in Section 4) are in Appendix A and Appendix B, respectively. Groundwater Monitoring Schedules (when issued throughout CY 2021) will be inserted in Appendix C, and addenda to this plan (if issued) will be inserted in Appendix D. Laboratory requirements (bottle lists, holding times, etc.) are provided in Appendix E, and an approved Waste Management Plan is provided in Appendix F. Modifications to the CY 2021 monitoring program may be necessary during implementation. Changes in programmatic requirements may alter the analytes specified for selected monitoring wells or may add or remove wells from the planned monitoring network. Each modification to the monitoring program will be approved by the Y-12 GWPP manager and documented as an addendum to this sampling and analysis plan.

54 ENVIRONMENTAL SCIENCES↗

Y-12 Groundwater Protection Program Groundwater and Surface Water Sampling and Analysis Plan for Calendar Year 2022

This plan provides a description of the groundwater and surface water quality monitoring activities planned for calendar year (CY) 2022 at the U.S. Department of Energy Y-12 National Security Complex (Y-12) that will be managed by the Y-12 Groundwater Protection Program (GWPP). Groundwater and surface water monitoring will be performed in three hydrogeologic regimes at Y-12: the Bear Creek Hydrogeologic Regime (Bear Creek Regime), the Upper East Fork Poplar Creek Hydrogeologic Regime (East Fork Regime), and the Chestnut Ridge Hydrogeologic Regime (Chestnut Ridge Regime). The Bear Creek and East Fork regimes are located in Bear Creek Valley and the Chestnut Ridge Regime is located south of Y-12. Additional surface water monitoring will be performed north of Pine Ridge along the boundary of the Oak Ridge Reservation. The following sections of this report provide details regarding the CY 2022 groundwater and surface water monitoring activities. Section 2 describes the monitoring locations in each regime and the processes used to select the sampling locations. A description of the field measurements and laboratory analytes is provided in Section 3. Sample collection methods and procedures are described in Section 4, and Section 5 lists the documents cited for more detailed operational and technical information.

54 ENVIRONMENTAL SCIENCES↗

Pathogenesis of sudden death following water immersion (immersion syndrome)

Sympathetic activity under cold stress is investigated. Predominantly vagal cardio-depressive reflexes are discussed besides currently known mechanisms of sudden death after water immersion. Pronounced circulatory centralization in diving animals as well as following exposure in cold water indicates additional sympathetic activity. In cold water baths of 15 C, measurements indicate an increase in plasma catecholamine levels by more than 300 percent. This may lead to cardiac arrhythmias by the following mechanisms: cold water essentially induces sinus bradycardia; brady-and tachycardiarrhythmias may supervene as secondary complications; sinusbradycardia may be enhanced by sympathetic hypertonus. Furthermore, ectopic dysrhythmias are liable to be induced by the strictly sympathetic innervation of the ventricle. Myocardial ischemia following a rise in peripheral blood pressure constitutes another arrhythmogenic factor. Some of these reactions are enhanced by alcohol intoxication.

Buhring, M.↗

Comparison of liquid absorption-release of superabsorbent polymers in alkali-activated slag and Portland cement systems: An NMR study combined with additional methods

In this study, {sup 1}H low-field NMR was used to compare the liquid absorption-release behaviour of superabsorbent polymers (SAPs) in Portland cement (PC) paste, NaOH-activated slag (SH-AAS) paste, and water glass-activated slag (WG-AAS) paste. The liquid absorption of SAPs in the PC paste was lower than that in the SH-AAS paste and the WG-AAS paste. The liquid release was also faster, which was mainly due to the higher Ca{sup 2+} concentration in the pore fluid of the PC system. In the AAS system, although the Ca{sup 2+} concentration in the pore fluid was low, the Na{sup +} concentration was much higher than that in the PC system due to the activator. The Ca{sup 2+} in the PC system is an important factor affecting the swelling of SAPs, while in the AAS system, the swelling limitation of SAPs is the result of the combined effects of Ca{sup 2+} and Na{sup +}, with Na{sup +} being dominant.

36 MATERIALS SCIENCE↗

Tuning electrochemically driven surface transformation in atomically flat LaNiO 3 thin films for enhanced water electrolysis

Structure–activity relationships built on descriptors of bulk and bulk-terminated surfaces are the basis for the rational design of electrocatalysts. However, electrochemically driven surface transformations complicate the identification of such descriptors. In this work, we demonstrate how the as-prepared surface composition of (001)-terminated LaNiO 3 epitaxial thin films dictates the surface transformation and the electrocatalytic activity for the oxygen evolution reaction. Specifically, the Ni termination (in the as-prepared state) is considerably more active than the La termination, with overpotential differences of up to 150 mV. A combined electrochemical, spectroscopic and density-functional theory investigation suggests that this activity trend originates from a thermodynamically stable, disordered NiO 2 surface layer that forms during the operation of Ni-terminated surfaces, which is kinetically inaccessible when starting with a La termination. Our work thus demonstrates the tunability of surface transformation pathways by modifying a single atomic layer at the surface and that active surface phases only develop for select as-synthesized surface terminations.

36 MATERIALS SCIENCE↗

Optimization of a Nafion Membrane-Based System for Removal of Chloride and Fluoride from Lunar Regolith-Derived Water

A long-term human presence in space will require self-sustaining systems capable of producing oxygen and potable water from extraterrestrial sources. Oxygen can be extracted from lunar regolith, and water contaminated with hydrochloric and hydrofluoric acids is produced as an intermediate in this process. We investigated the ability of Nafion proton exchange membranes to remove hydrochloric and hydrofluoric acids from water. The effect of membrane thickness, product stream flow rate, and acid solution temperature and concentration on water flux, acid rejection, and water and acid activity were studied. The conditions that maximized water transport and acid rejection while minimizing resource usage were determined by calculating a figure of merit. Water permeation is highest at high solution temperature and product stream flow rate across thin membranes, while chloride and fluoride permeation are lowest at low acid solution temperature and concentration across thin membranes. The figure of merit varies depending on the starting acid concentration; at low concentration, the figure of merit is highest across a thin membrane, while at high concentration, the figure of merit is highest at low solution temperature. In all cases, the figure of merit increases with increasing product stream flow rate.

Anthony, Stephen M.↗

Review of historical monitoring data on Techa River contamination

The Mayak Production Association was the first Russian site for the production and separation of plutonium. The extensive increase in plutonium production during 1948-1955, as well as the absence of reliable waste-management technology, resulted in significant releases of liquid radioactive effluent into the rather small Techa River. This resulted in chronic external and internal exposure of about 30,000 residents of riverside communities; these residents form the cohort of an epidemiologic investigation. Analysis of the available historical monitoring data indicates that the following reliable data sets can be used for reconstruction of doses received during the early periods of operation of the Mayak Production Association: Temporal pattern of specific beta activity of river water for several sites in the upper Techa region since July 1951; average annual values of specific beta activity of river water and bottom sediments as a function of downstream distance for the whole river since 1951; external gamma-exposure rates near the shoreline as a function of downstream distance for the whole Techa River since 1952; and external gamma-exposure rate as a function of distance from the shoreline for several sites in the upper and middle Techa since 1951.

NASA Discipline Radiation Health↗

Water Vapor Column Measurements with Infrared Active Optical IPDA Lidar

Development of a novel triple-pulsed 2-μm direct detection Integrated Path Differential Absorption (IPDA) lidar to measure column average carbon dioxide (XCO2) and water vapor (XH2O) from an airborne platform provides a new tool to advance atmospheric science studies. Column water vapor measurements are used in global mapping of weather fronts, weather forecast, and in studies of atmospheric transport, radiation, clouds and climate. Water vapor interference is source of biases in XCO2 measurements due to overlap in absorption, line broadening, and retrieval of dry air mixing of carbon dioxide. Model calculations show a XH2O measurement capability of 0.5% accuracy over 1.0 km spatial scales from the NASA B-200 aircraft. Ground testing of the integrated IPDA was in progress during December 2017-January 2018, and airborne measurements and validation of XH2O measurements over land and ocean are planned during January-February 2018. Technology developments in the measurement of XH2O are presented along with performance projections, and results from ground and airborne testing and validations in this paper.

Singh, Upendra N.↗

Ruthenium-lead oxide for acidic oxygen evolution reaction in proton exchange membrane water electrolysis

Developing an active and stable anode catalyst for the proton exchange membrane water electrolyzer (PEM-WE) is a critical objective to enhance the economic viability of green hydrogen technology. However, the expensive iridium-based electrocatalyst remains the sole practical material with industrial-level stability for the acidic oxygen evolution reaction (OER) at the anode. Ruthenium-based catalysts have been proposed as more cost-effective alternatives with improved activity, though their stability requires enhancement. The current urgent goal is to reduce costs and noble metal loading of the OER catalyst while maintaining robust activity and stability. Here, in this study, we design a Ru-based OER catalyst incorporating Pb as a supporting element. This electrocatalyst exhibits an OER overpotential of 201 mV at 10 mA.cm -2 , simultaneously reducing Ru noble metal loading by similar to 40%. Normalization of the electrochemically active surface area unveils improved intrinsic activity compared to the pristine RuO 2 catalyst. During a practical stability test in a PEM-WE setup, our developed catalyst sustains stable performance over 300 h without notable degradation, underscoring its potential for future applications as a reliable anodic catalyst.

Electrocatalysis↗

Applications of MODIS Fluorescent Line Height Measurements to Monitor Water Quality Trends and Algal Bloom Activity

Recent advances in satellite and airborne remote sensing, such as improvements in sensor and algorithm calibrations, processing techniques and atmospheric correction procedures have provided for increased coverage of remote-sensing, ocean-color products for coastal regions. In particular, for the Moderate Resolution Imaging Spectrometer (MODIS) sensor calibration updates, improved aerosol retrievals and new aerosol models has led to improved atmospheric correction algorithms for turbid waters and have improved the retrieval of ocean color in coastal waters. This has opened the way for studying ocean phenomena and processes at finer spatial scales, such as the interactions at the land-sea interface, trends in coastal water quality and algal blooms. Human population growth and changes in coastal management practices have brought about significant changes in the concentrations of organic and inorganic, particulate and dissolved substances entering the coastal ocean. There is increasing concern that these inputs have led to declines in water quality and have increase local concentrations of phytoplankton, which cause harmful algal blooms. In two case studies we present MODIS observations of fluorescence line height (FLH) to 1) assess trends in water quality for Tampa Bay, Florida and 2) illustrate seasonal and annual variability of algal bloom activity in Monterey Bay, California as well as document estuarine/riverine plume induced red tide events. In a comprehensive analysis of long term (2003-2011) in situ monitoring data and satellite imagery from Tampa Bay we assess the validity of the MODIS FLH product against chlorophyll-a and a suite of water quality parameters taken in a variety of conditions throughout a large optically complex estuarine system. A systematic analysis of sampling sites throughout the bay is undertaken to understand how the relationship between FLH and in situ chlorophyll-a responds to varying conditions and to develop a near decadal trend in water quality changes. In situ monitoring locations that correlated well with satellite imagery were in depths greater than seven meters and were located over five kilometers from shore. Water quality parameter of total nitrogen, phosphorous, turbidity and biological oxygen demand had high correlations with these sites, as well. Satellite FLH estimates show improving water quality from 2003-2007 with a slight decline up through 2011. Dinoflagellate blooms in Monterey Bay, California (USA) have recently increased in frequency and intensity. Nine years of MODIS FLH observations are used to describe the annual and seasonal variability of bloom activity within the Bay. Three classes of MODIS algorithms were correlated against in situ chlorophyll measurements. The FLH algorithm provided the most robust estimate of bloom activity. Elevated concentrations of phytoplankton were evident during the months of August-November, a period during which increased occurrences of dinoflagellate blooms have been observed in situ. Seasonal patterns of FLH show the on- and offshore movement of areas of high phytoplankton biomass between oceanographic seasons. Higher concentrations of phytoplankton are also evident in the vicinity of the land-based nutrient sources and outflows, and the cyclonic bay-wide circulation can transport these nutrients to the northern Bay bloom incubation region. Both of these case studies illustrate the utility MODIS FLH observations in supporting management decisions in coastal and estuarine waters.

Fischer, Andrew↗

Tradeoffs in forest resilience to satellite-based estimates of water and productivity losses

Climate change is expected to intensify the global hydrological cycle via increased evapotranspiration (ET). Changes in ET have important consequences for water-related ecosystem services as well as for forest productivity. Forests play a critical role in ET: active trees sequester carbon at the expense of losing water, yet if they are not active, water remains in the trees, but productivity stalls. Here, we estimated the capacity of forests to recover (resilience) from extreme water or productivity losses based on modeled ET through remote sensing methods across the conterminous USA. Results show there is a spatial tradeoff in resilience to water or productivity losses. Forests were more resilient to water loss in the drier west, and more resilient to productivity loss in the wetter east. Still, resilience was highly heterogeneous across the continent. Projections under climate change indicate both declines and increases of up to 13% in forest resilience, with broad regional trends but high spatial heterogeneity within regions. This study brings crucial satellite-based insights on how water dynamics, and consequentially productivity and water provision in forests, might be impacted by climate change.

54 ENVIRONMENTAL SCIENCES↗

Green Hydrogen: A Briefing for Land Managers

Decarbonization goals for the U.S. are emphasizing reliance on clean hydrogen produced from renewable resources. Hydrogen can be produced by splitting water, stored, transported, and converted to energy or chemicals. These activities require land, water, and energy. This fact sheet provides insight for federal and state land managers on the resources required to facilitate clean hydrogen production and related activities.

electrolysis↗

Structural Implications of Interfacial Hydrogen Bonding in Hydrated Wyoming-Montmorillonite Clay

Montmorillonite (MMT) clay - a layered porous nanomaterial used as seals in engineered waste containment barriers for spent nuclear fuel - adopts discrete hydration/swelling states depending upon surrounding water and ion activities and confining pressure. The structure of nanoconfined water and charge-balancing counterions in the clay mineral interlayers dictate the swelling and mechanical behavior of MMT, so a molecular model for this clay with high structural fidelity is required to accurately predict the reliability of long-term nuclear waste storage. Here, we present a molecular model for MMT that is based on high resolution transmission electron microscopy of Wyoming-MMT single crystals. Imaging data unambiguously show a cis-vacant arrangement of structural hydroxyl groups in the octahedral sheet, whereas existing molecular models assume a centrosymmetric trans-vacant configuration for MMT. Furthermore, using atomistic simulations, we find that the cis-vacant arrangement of structural hydroxyl groups significantly affects the structure of adsorbed water yielding a larger population of hydrogen bonds with bridging oxygens on the tetrahedral sheet and weak hydrogen bonding between the hydroxyl groups in the octahedral sheet and water in the clay mineral interlayers. As a result, water adsorbed in the interlayer is more "ice-like", with stronger ordering and lower density, although the diffusivity of the interlayer species is not significantly diminished. Our improved structural model for MMT provides insight into the energetics of water adsorption, which ultimately dictates its pore- to macro-scale swelling, transport, and fracture properties.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗