Search

One of the objectives of the Deep Convective Clouds and Chemistry (DC3) field experiment was to determine the scavenging of soluble trace gases by thunderstorms. We present an analysis of scavenging of hydrogen peroxide (H2O2) and methyl hydrogen peroxide (CH3OOH) from six DC3 cases that occurred in Oklahoma and northeast Colorado. Estimates of H2O2 scavenging efficiencies are comparable to previous studies ranging from 79 to 97% with relative uncertainties of 5–25%. CH3OOH scavenging efficiencies ranged from 12 to 84% with relative uncertainties of 18–558%. The wide range of CH3OOH scavenging efficiencies is surprising, as previous studies suggested that CH3OOH scavenging efficiencies would be

Despite a substantial impact on various economic and cell technology factors, the influence of electrolyte quantities is rarely addressed in research. This study examines the impact of varying electrolyte quantities on cell performance and aging processes using three different electrolytes: LP57 (1 M LiPF6 in ethylene carbonate:ethyl methyl carbonate (EC:EMC 3:7 w/w), LP572 (LP57+2 wt.% vinylene carbonate (VC)) and LP57 + absVC (18.351 mg VC). Comprehensive analytical post mortem investigations revealed that continuous excessive electrolyte decomposition determines the performance of cells using LP57, leading to enhanced irreversible lithium-ion loss and interphase thickening with increasing electrolyte volume. Impedance rise due to the growth of the interphase was also identified as the cause of degrading cell performance with rising amounts of LP572, attributed to an increasingly pronounced consumption of VC rather than electrolyte aging effects. By varying the electrolyte quantity while maintaining a constant amount VC within the cell system, the differences in cell performance were minimized, and observed deteriorating effects were suppressed. This study demonstrates the sensitive interdependence of electrolyte volume and additive concentration, practically affecting aging behavior. Comprehensively understanding the characteristics of each individual electrolyte component and tailoring the electrolytes to cell-specific cell properties proves to be crucial to optimize cell performance., (© 2024 The Author(s). Advanced Science published by Wiley‐VCH GmbH.)

Continuous lithium (Li) depletion shadows the increase in energy density and safety properties promised by zero-excess lithium metal batteries (ZELMBs). Guiding the Li deposits toward more homogeneous and denser lithium morphology results in improved electrochemical performance. Herein, a lithium nitrate (LiNO 3 ) enriched separator that improves the morphology of the Li deposits and facilitates the formation of an inorganic-rich solid-electrolyte interphase (SEI) resulting in an extended cycle life in Li||Li-cells as well as an increase of the Coulombic efficiency in Cu||Li-cells is reported. Using a LiNi 0.6 Co 0.2 Mn 0.2 O 2 positive electrode in NCM622||Cu-cells, a carbonate-based electrolyte, and a LiNO 3 enriched separator, an extension of the cycle life by more than 50 cycles with a moderate capacity fading compared to the unmodified separator is obtained. The relative constant level of LiNO 3 in the electrolyte, maintained by the LiNO 3 enriched separator throughout the cycling process stems at the origin of the improved performance. Ion chromatography measurements carried out at different cycles support the proposed mechanism of a slow and constant release of LiNO 3 from the separator. The results indicate that the strategy of using a LiNO 3 enriched separator instead of LiNO 3 as a sacrificial electrolyte additive can improve the performance of ZELMBs further by maintaining a compact and thus stable SEI layer on Li deposits., (© 2023 The Authors. Small published by Wiley-VCH GmbH.)

Fire is an integral component of ecosystems globally and a tool that humans have harnessed for millennia. Altered fire regimes are a fundamental cause and consequence of global change, impacting people and the biophysical systems on which they depend. As part of the newly emerging Anthropocene, marked by human-caused climate change and radical changes to ecosystems, fire danger is increasing, and fires are having increasingly devastating impacts on human health, infrastructure, and ecosystem services. Increasing fire danger is a vexing problem that requires deep transdisciplinary, trans-sector, and inclusive partnerships to address. Here, we outline barriers and opportunities in the next generation of fire science and provide guidance for investment in future research. We synthesize insights needed to better address the long-standing challenges of innovation across disciplines to (i) promote coordinated research efforts; (ii) embrace different ways of knowing and knowledge generation; (iii) promote exploration of fundamental science; (iv) capitalize on the "firehose" of data for societal benefit; and (v) integrate human and natural systems into models across multiple scales. Fire science is thus at a critical transitional moment. We need to shift from observation and modeled representations of varying components of climate, people, vegetation, and fire to more integrative and predictive approaches that support pathways toward mitigating and adapting to our increasingly flammable world, including the utilization of fire for human safety and benefit. Only through overcoming institutional silos and accessing knowledge across diverse communities can we effectively undertake research that improves outcomes in our more fiery future., (Published by Oxford University Press on behalf of National Academy of Sciences 2022.)

The Amazon rainforest suffers increasing pressure from anthropogenic activities. A key aspect not fully understood is how anthropogenic atmospheric emissions within the basin interact with biogenic emissions and impact the forest's atmosphere and biosphere. We combine a high-resolution atmospheric chemical transport model with an improved emissions inventory and in-situ measurements to investigate a surprisingly high concentration of ozone (O 3 ) and secondary organic aerosol (SOA) 150-200 km downwind of Manaus city in an otherwise pristine forested region. We show that atmospheric dynamics and photochemistry determine a gross production of secondary pollutants seen in the simulation. After sunrise, the erosion of the nocturnal boundary layer mixes natural forest emissions, rich in biogenic volatile organic compounds, with a lofted pollution layer transported overnight, rich in nitrogen oxides and formaldehyde. As a result, O 3 and SOA concentrations greater than ∼47 ppbv and 1.8 μg m -3 , respectively, were found, with maximum concentrations occurring at 2 pm LT, 150-200 km downwind of Manaus city. These high concentrations affect a large primary forested area of about 11,250 km 2 . These oxidative areas are under a NO x -limited regime so that changes in NO x emissions from Manaus have a significant impact on O 3 and SOA production.

Carbonaceous emissions from wildfires are a dynamic mixture of gases and particles that have important impacts on air quality and climate. Emissions that feed atmospheric models are estimated using burned area and fire radiative power (FRP) methods that rely on satellite products. These approaches show wide variability and have large uncertainties, and their accuracy is challenging to evaluate due to limited aircraft and ground measurements. Here, we present a novel method to estimate fire plume-integrated total carbon and speciated emission rates using a unique combination of lidar remote sensing aerosol extinction profiles and in situ measured carbon constituents. We show strong agreement between these aircraft-derived emission rates of total carbon and a detailed burned area-based inventory that distributes carbon emissions in time using Geostationary Operational Environmental Satellite FRP observations (Fuel2Fire inventory, slope = 1.33 ± 0.04, r 2 = 0.93, and RMSE = 0.27). Other more commonly used inventories strongly correlate with aircraft-derived emissions but have wide-ranging over- and under-predictions. A strong correlation is found between carbon monoxide emissions estimated in situ with those derived from the TROPOspheric Monitoring Instrument (TROPOMI) for five wildfires with coincident sampling windows (slope = 0.99 ± 0.18; bias = 28.5%). Smoke emission coefficients (g MJ -1 ) enable direct estimations of primary gas and aerosol emissions from satellite FRP observations, and we derive these values for many compounds emitted by temperate forest fuels, including several previously unreported species.

Background: Systemic lupus erythematosus (SLE) is an autoimmune condition with a wide spectrum of clinical manifestations encompassing most organs and systems. Its treatment approach includes different immunomodulatory treatments, of which B-cell targeted therapies are part of. Rituximab (an anti-CD20 antibody) had encouraging results in observational studies but failed when tested in clinical trials. It is theorized that this could have been partially due to BAFF upregulation, leading to rituximab failure. Therefore, targeting BAFF with belimumab after rituximab therapy, may have a synergic effect in SLE. Objective: We review the available observational data regarding sequential rituximab/belimumab therapy in SLE patients. Results: Twenty-four patients from 6 studies were included. The results suggest a benefit with this combined therapy, with reduction of the mean SLEDAI. However, there was significant drug regimen and patient selection heterogeneity. Conclusion: Further randomized clinical trials are needed to examine this drug sequencing protocol in SLE patients.

Although cyclodextrins (CDs) have been used as additives to small molecule surfactants, there are only a few examples of this cyclic oligosaccharide being used as a surfactant template. Herein, we present a novel ionic β-CD derivative that shows significant surface activity and stabilizes oil-in-water emulsions prepared with hexadecane as a model oil. The macrocyclic surfactant strongly reduces the oil-water surface tension with increasing concentration and shows a critical micelle concentration (CMC) around 5 mM. We demonstrate the stability of the oil-in-water emulsions and verify the possibility to address the emulsion droplet surface using molecular recognition of the β-CD cavity at the oil-water interface.

Deep convective transport of surface moisture and pollution from the planetary boundary layer to the upper troposphere and lower stratosphere affects the radiation budget and climate. This study uses cloud-parameterized Weather Research and Forecasting model coupled with Chemistry simulations to analyze the subgrid deep convective transport of CO at 12- and 36-km horizontal resolution in supercell and mesoscale convective systems observed during the 2012 Deep Convective Clouds and Chemistry field campaign and compares the simulation results with aircraft measurements and cloud-resolved simulations. The best Weather Research and Forecasting simulation of these storms was obtained with the use of the Grell-Freitas convective scheme. The default Weather Research and Forecasting model coupled with Chemistry subgrid convective transport scheme was replaced with a scheme to compute convective transport within the Grell-Freitas subgrid cumulus parameterization, which resulted in improved transport simulations. We examined the CO tendencies due to subgrid- and grid-scale convective transport. Results showed that the subgrid convective transport started earlier than the grid-scale convective transport. The subgrid-scale convective transport reached its maximum during the hour prior to the formation of the grid-scale constant-altitude detrainment layer. After that, both the subgrid- and grid-scale convective transport began to decrease. The subgrid-scale convective transport played a more significant role in the supercell case than the mesoscale convective system case. Subgrid contribution reached ~90% at the beginning of the storm and decreased to ~30% (17%) for the 36-km (12-km) domain 4 hr later.

Deep convective transport of gaseous precursors to ozone (O 3 ) and aerosols to the upper troposphere is affected by liquid phase and mixed-phase scavenging, entrainment of free tropospheric air and aqueous chemistry. The contributions of these processes are examined using aircraft measurements obtained in storm inflow and outflow during the 2012 Deep Convective Clouds and Chemistry (DC3) experiment combined with high-resolution (d x ≤ 3 km) WRF-Chem simulations of a severe storm, an air mass storm, and a mesoscale convective system (MCS). The simulation results for the MCS suggest that formaldehyde (CH 2 O) is not retained in ice when cloud water freezes, in agreement with previous studies of the severe storm. By analyzing WRF-Chem trajectories, the effects of scavenging, entrainment, and aqueous chemistry on outflow mixing ratios of CH 2 O, methyl hydroperoxide (CH 3 OOH), and hydrogen peroxide (H 2 O 2 ) are quantified. Liquid phase microphysical scavenging was the dominant process reducing CH 2 O and H 2 O 2 outflow mixing ratios in all three storms. Aqueous chemistry did not significantly affect outflow mixing ratios of all three species. In the severe storm and MCS, the higher than expected reductions in CH 3 OOH mixing ratios in the storm cores were primarily due to entrainment of low-background CH 3 OOH. In the air mass storm, lower CH 3 OOH and H 2 O 2 scavenging efficiencies (SEs) than in the MCS were partly due to entrainment of higher background CH 3 OOH and H 2 O 2 . Overestimated rain and hail production in WRF-Chem reduces the confidence in ice retention fraction values determined for the peroxides and CH 2 O.