High Temperature Electrochemical Engineering and Clean Energy Systems

Global power demand is projected to more than double by 2050 and meeting this increased power demand will require maintaining or increasing power output from all existing energy sources while adding a large amount of new capacity. The power sources that have the greatest opportunity to fulfill this demand gap over this time period are clean energy sources including solar and nuclear power. One of the areas of expertise that SRNL has been applying to help with a variety of clean energy technologies is in high temperature electrochemistry. Savannah River National Laboratory (SRNL) in collaboration with industrial and university partners has used high temperature electrochemical engineering to make improvements in solar power, nuclear fuel reprocessing, and fusion energy technologies. This article describes how high temperature electrochemistry has been applied at SRNL to mitigate corrosion in high temperature CSP systems, develop novel methods of nuclear fuel processing, and recover tritium in fusion energy technologies

A revised Plio-Pleistocene age model and paleoceanography of the northeastern Caribbean Sea: IODP Site U1396 off Montserrat, Lesser Antilles

Site U1396 was piston cored as a part of Integrated Ocean Drilling Project Expedition 340 to establish a long record for Lesser Antilles volcanism. A ~150 m sediment succession was recovered from three holes on a bathymetric high ~33 km southwest of Montserrat. A series of shipboard and newly-generated chronostratigraphic tools (biostratigraphy, magnetostratigraphy, astrochronology, and stable isotope chemostratigraphy) were employed to generate an integrated age model. Two possible chronostratigraphic interpretations for the Brunhes chron are presented, with hypotheses to explain the discrepancies seen between this study and Wall-Palmer et al. (2014). The recent Wade et al. (2011) planktic foraminiferal biostratigraphic calibration is tested, revealing good agreement between primary datums observed at Site U1396 and calibrated ages, but significant mismatches for some secondary datums. Sedimentation rates are calculated, both including and excluding the contribution of discrete volcanic sediment layers within the succession. Rates are found to be ‘pulsed’ or highly variable within the Pliocene interval, declining through the 1.5-2.4 Ma interval, and then lower through the Pleistocene. Different explanations for the trends in the sedimentation rates are discussed, including orbitally-forced biogenic production spikes, elevated contributions of cryptotephra (dispersed ash), and changes in bottom water sources and flow rates with increased winnowing in the area of Site U1396 into the Pleistocene

Computational thermal, chemical, fluid, and solid mechanics for geosystems management.

This document summarizes research performed under the SNL LDRD entitled - Computational Mechanics for Geosystems Management to Support the Energy and Natural Resources Mission. The main accomplishment was development of a foundational SNL capability for computational thermal, chemical, fluid, and solid mechanics analysis of geosystems. The code was developed within the SNL Sierra software system. This report summarizes the capabilities of the simulation code and the supporting research and development conducted under this LDRD. The main goal of this project was the development of a foundational capability for coupled thermal, hydrological, mechanical, chemical (THMC) simulation of heterogeneous geosystems utilizing massively parallel processing. To solve these complex issues, this project integrated research in numerical mathematics and algorithms for chemically reactive multiphase systems with computer science research in adaptive coupled solution control and framework architecture. This report summarizes and demonstrates the capabilities that were developed together with the supporting research underlying the models. Key accomplishments are: (1) General capability for modeling nonisothermal, multiphase, multicomponent flow in heterogeneous porous geologic materials; (2) General capability to model multiphase reactive transport of species in heterogeneous porous media; (3) Constitutive models for describing real, general geomaterials under multiphase conditions utilizing laboratory data; (4) General capability to couple nonisothermal reactive flow with geomechanics (THMC); (5) Phase behavior thermodynamics for the CO2-H2O-NaCl system. General implementation enables modeling of other fluid mixtures. Adaptive look-up tables enable thermodynamic capability to other simulators; (6) Capability for statistical modeling of heterogeneity in geologic materials; and (7) Simulator utilizes unstructured grids on parallel processing computers

Heat flow in the Lesser Antilles island arc and adjacent back arc Grenada basin

Using temperature gradients measured in 10 holes at 6 sites, we generate the first high fidelity heat flow measurements from Integrated Ocean Drilling Program drill holes across the northern and central Lesser Antilles arc and back arc Grenada basin. The implied heat flow, after correcting for bathymetry and sedimentation effects, ranges from about 0.1 W/m² on the crest of the arc, midway between the volcanic islands of Montserrat and Guadeloupe, to 15 km from the crest in the back arc direction. Combined with previous measurements, we find that the magnitude and spatial pattern of heat flow are similar to those at continental arcs. The heat flow in the Grenada basin to the west of the active arc is 0.06 W/m², a factor of 2 lower than that found in the previous and most recent study. There is no thermal evidence for significant shallow fluid advection at any of these sites. Present-day volcanism is confined to the region with the highest heat flow.American Geophysical Union – Geochemistry, Geophysics, Geosystems. This is the publisher’s final pdf. The published article is copyrighted by the American Geophysical Union and can be found at: http://www.agu.org/journals/gc/.Keywords: volcanic arc., Lesser Antilles, IODP, heat flow, back arc, Grenada basinKeywords: volcanic arc., Lesser Antilles, IODP, heat flow, back arc, Grenada basi

Permeability and pressure measurements in Lesser Antilles submarine slides: Evidence for pressure-driven slow-slip failure

Recent studies hypothesize that some submarine slides fail via pressure-driven slow-slip deformation. To test this hypothesis, this study derives pore pressures in failed and adjacent unfailed deep marine sediments by integrating rock physics models, physical property measurements on recovered sediment core, and wireline logs. Two drill sites (U1394 and U1399) drilled through interpreted slide debris; a third (U1395) drilled into normal marine sediment. Near-hydrostatic fluid pressure exists in sediments at site U1395. In contrast, results at both sites U1394 and U1399 indicate elevated pore fluid pressures in some sediment. We suggest that high pore pressure at the base of a submarine slide deposit at site U1394 results from slide shearing. High pore pressure exists throughout much of site U1399, and Mohr circle analysis suggests that only slight changes in the stress regime will trigger motion. Consolidation tests and permeability measurements indicate moderately low (~10⁻¹⁶–10⁻¹⁷ m²) permeability and overconsolidation in fine-grained slide debris, implying that these sediments act as seals. Three mechanisms, in isolation or in combination, may produce the observed elevated pore fluid pressures at site U1399: (1) rapid sedimentation, (2) lateral fluid flow, and (3) shearing that causes sediments to contract, increasing pore pressure. Our preferred hypothesis is this third mechanism because it explains both elevated fluid pressure and sediment overconsolidation without requiring high sedimentation rates. Our combined analysis of subsurface pore pressures, drilling data, and regional seismic images indicates that slope failure offshore Martinique is perhaps an ongoing, creep-like process where small stress changes trigger motion

Results of the COVID-19 mental health international for the general population (COMET-G) study.

INTRODUCTION: There are few published empirical data on the effects of COVID-19 on mental health, and until now, there is no large international study. MATERIAL AND METHODS: During the COVID-19 pandemic, an online questionnaire gathered data from 55,589 participants from 40 countries (64.85% females aged 35.80 ± 13.61; 34.05% males aged 34.90±13.29 and 1.10% other aged 31.64±13.15). Distress and probable depression were identified with the use of a previously developed cut-off and algorithm respectively. STATISTICAL ANALYSIS: Descriptive statistics were calculated. Chi-square tests, multiple forward stepwise linear regression analyses and Factorial Analysis of Variance (ANOVA) tested relations among variables. RESULTS: Probable depression was detected in 17.80% and distress in 16.71%. A significant percentage reported a deterioration in mental state, family dynamics and everyday lifestyle. Persons with a history of mental disorders had higher rates of current depression (31.82% vs. 13.07%). At least half of participants were accepting (at least to a moderate degree) a non-bizarre conspiracy. The highest Relative Risk (RR) to develop depression was associated with history of Bipolar disorder and self-harm/attempts (RR = 5.88). Suicidality was not increased in persons without a history of any mental disorder. Based on these results a model was developed. CONCLUSIONS: The final model revealed multiple vulnerabilities and an interplay leading from simple anxiety to probable depression and suicidality through distress. This could be of practical utility since many of these factors are modifiable. Future research and interventions should specifically focus on them

Pollutants and Foraminiferal Assemblages in Torrecillas Lagoon: An Environmental Micropaleontology Approach

Torrecillas Lagoon in the North Coast of Puerto Rico has experienced extensive anthropogenic influence over the past 400 years. Elevated concentrations of Potential Toxic Elements (PTEs) have been reported in surficial sediments. The main goal of this dissertation was to implement in Puerto Rico the use of benthic foraminifers as a bioindicators of PTEs and to compare the impact of Cu(II) on field samples with results of experimental work using cultures. Analyses included geochemical assessment for bulk and carbonate- soluble bioavailable concentrations of PTEs in surface, core and pore-water samples, as well as analyses of grain-size, Percent Total Organic Carbon (%TOC), Percent Carbonate (%CO3), foraminiferal assemblages and distribution, and ecological indices. PTEs of concern (Cu, Zn, Ni, Pb, Cr, As, Li, Se, Fe, Mn, V, Se) have relatively uniform spatial distributions. Areas with higher concentrations are associated with higher %TOC and %mud, as well as with anoxic conditions. Temporal distributions show limited variability although an overall decrease in enrichment indicates improvement of environmental conditions in the 20th century. Ammonia beccarii, Quinquloculina rhodiensis, Q. seminulum, and Ammobaculites agglutinans are the dominant foraminifers in the lagoon and are characteristic of stressed coastal environments. Several PTEs, including bioavailable Cu and Zn are negatively correlated with the dominant foraminiferal taxa and with diversity indices, indicating that these pollutants are influencing the spatial and temporal distributions of foraminiferal assemblages. Ammonia beccarii abundance negatively correlates with bulk concentration of Cu(II) and exhibits no correlation with its bioavailable fraction. These observations suggest that fractionation and bioavailability of PTEs need to be considered more in depth as influences on ecological indices and foraminiferal behavior. Exchangeable and oxidizable fractions are considered the most likely to influence the ecology of foraminifers under most circumstances. Ammonia aomoriensi was exposed to Cu(II) concentrations (0–0.32 µmol/L) under controlled conditions (25ºC, 35PSU and pH= 7.8). After a 23-day treatment, foraminifers exposed to 0.22 and 0.32 µmol/L concentrations exhibited reduced growth and morphological deformities in which the long axis of the chamber extended ventrally, increasing the height of the trochospire. The waters in Torrecillas lagoon show strong stratification, with hypoxic/anoxic (DO/L) and corrosive (pH\u3c 7.4) conditions below 4 m depth. The presence of such strong gradients in very shallow water represents a dynamic chemical environment, with changes occurring on day-night cycles, tidal cycles, and especially with storm activity that induces mixing of otherwise highly stratified, very localized waters. Recognizing the potential for sequestered PTEs to be mobilized is essential insight for coastal management agencies that must assess the risks of existing PTEs during coastal engineering activities (e.g., dredge and fill activities) and major storm events

Pollutants and Foraminiferal Assemblages in Torrecillas Lagoon: An Environmental Micropaleontology Approach

Torrecillas Lagoon in the North Coast of Puerto Rico has experienced extensive anthropogenic influence over the past 400 years. Elevated concentrations of Potential Toxic Elements (PTEs) have been reported in surficial sediments. The main goal of this dissertation was to implement in Puerto Rico the use of benthic foraminifers as a bioindicators of PTEs and to compare the impact of Cu(II) on field samples with results of experimental work using cultures. Analyses included geochemical assessment for bulk and carbonate- soluble bioavailable concentrations of PTEs in surface, core and pore-water samples, as well as analyses of grain-size, Percent Total Organic Carbon (%TOC), Percent Carbonate (%CO3), foraminiferal assemblages and distribution, and ecological indices. PTEs of concern (Cu, Zn, Ni, Pb, Cr, As, Li, Se, Fe, Mn, V, Se) have relatively uniform spatial distributions. Areas with higher concentrations are associated with higher %TOC and %mud, as well as with anoxic conditions. Temporal distributions show limited variability although an overall decrease in enrichment indicates improvement of environmental conditions in the 20th century. Ammonia beccarii, Quinquloculina rhodiensis, Q. seminulum, and Ammobaculites agglutinans are the dominant foraminifers in the lagoon and are characteristic of stressed coastal environments. Several PTEs, including bioavailable Cu and Zn are negatively correlated with the dominant foraminiferal taxa and with diversity indices, indicating that these pollutants are influencing the spatial and temporal distributions of foraminiferal assemblages. Ammonia beccarii abundance negatively correlates with bulk concentration of Cu(II) and exhibits no correlation with its bioavailable fraction. These observations suggest that fractionation and bioavailability of PTEs need to be considered more in depth as influences on ecological indices and foraminiferal behavior. Exchangeable and oxidizable fractions are considered the most likely to influence the ecology of foraminifers under most circumstances. Ammonia aomoriensi was exposed to Cu(II) concentrations (0–0.32 µmol/L) under controlled conditions (25ºC, 35PSU and pH= 7.8). After a 23-day treatment, foraminifers exposed to 0.22 and 0.32 µmol/L concentrations exhibited reduced growth and morphological deformities in which the long axis of the chamber extended ventrally, increasing the height of the trochospire. The waters in Torrecillas lagoon show strong stratification, with hypoxic/anoxic (DO/L) and corrosive (pH\u3c 7.4) conditions below 4 m depth. The presence of such strong gradients in very shallow water represents a dynamic chemical environment, with changes occurring on day-night cycles, tidal cycles, and especially with storm activity that induces mixing of otherwise highly stratified, very localized waters. Recognizing the potential for sequestered PTEs to be mobilized is essential insight for coastal management agencies that must assess the risks of existing PTEs during coastal engineering activities (e.g., dredge and fill activities) and major storm events

Foraminifera as Bioindicators of Water Quality: The FoRAM Index Revisited

Coral reefs worldwide are degrading at alarming rates due to local and global stressors. There are ongoing needs for bioindicator systems that can be used to assess reef health status, the potential for recovery following destructive events such as tropical storms, and for the success of coral transplants. Benthic foraminiferal shells are ubiquitous components of carbonate sediment in reef environments that can be sampled at minimal cost and environmental impact. Here we review the development and application of the FoRAM Index (FI), which provides a bioindicator metric for water quality that supports reef accretion. We outline the strengths and limitations of the FI, and propose how it can be applied more effectively across different geographical regions

Temporal Variability in Potentially Toxic Elements (Pte\u27S) and Benthic Foraminifera in an Estuarine Environment in Puerto Rico

Bulk concentrations of PTEs (potentially toxic elements) were assessed and compared with foraminiferal assemblages from core sediments from TL (Torrecillas Lagoon), on the north coast of Puerto Rico. Temporal distributions of mud, Fe, Al (proxy for terrigenous sedimentation), and rhenium (proxy for anoxia) reflected changes in land use within the drainage basin associated with human activities over the past century. The mud-dominated sediments provided a major sink for PTEs, while Fe oxides and sulfides served as a secondary sinks . Temporal variability of Re revealed intervals of aerobic vs anaerobic conditions in the lagoon. The dominant foraminiferal taxa, Ammonia beccarii, Quinqueloculina rhodiensis, Quinqueloculina seminula, and Ammobaculites agglutinans, coupled with low foraminiferal densities and species diversities, as well as barren samples, are characteristic of stressed estuarine environments. Overall bulk concentrations of Cu and Zn negatively correlated with foraminiferal absolute/relative abundances, diversity indices and incidences of test deformities. However, there are no correlations with the assumed bioavailable counterparts (F2Tess-Cu and F2Tess-Zn) were observed. These results indicate that fractionation of PTEs need to be considered in relation to their biological significance to foraminiferal ecology, which may differ substantially from bioavailability to metazoans that ingest sediments. The application of the acid-soluble F2Tess is not recommended in environmental studies using foraminifers as bioindicators, as PTEs in this fraction are likely not bioavailable to these protists