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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
DOE OSTI2024

Breakthrough innovations in carbon dioxide mineralization for a sustainable future

Greenhouse gas emissions and climate change concerns have prompted worldwide initiatives to lower carbon dioxide (CO 2 ) levels and prevent them from rising in the atmosphere, thereby controlling global warming. Effective CO 2 management through carbon capture and storage is essential for safe and permanent storage, as well as synchronically meeting carbon reduction targets. Lowering CO 2 emissions through carbon utilization can develop a wide range of new businesses for energy security, material production, and sustainability. CO 2 mineralization is one of the most promising strategies for producing thermodynamically stable solid calcium or magnesium carbonates for long-term sequestration using simple chemical reactions. Current advancements in CO 2 mineralization technologies, focusing on pathways and mechanisms using different industrial solid wastes, including natural minerals as feedstocks, are briefly discussed. However, the operating costs, energy consumption, reaction rates, and material management are major barriers to the application of these technologies in CO 2 mineralization. Further, the optimization of operating parameters, tailor-made equipment, and smooth supply of waste feedstocks require more attention to make the carbon mineralization process economically and commercially viable. Here, carbonation mechanisms, technological options to expedite mineral carbonation, environmental impacts, and prospects of CO 2 mineralization technologies are critically evaluated to suggest a pathway for mitigating climate change in the future. The integration of industrial wastes and brine with the CO 2 mineralization process can unlock its potential for the development of novel chemical pathways for the synthesis of calcium or magnesium carbonates, valuable metal recovery, and contribution to sustainability goals while reducing the impact of global warming.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2025

Direct Air Capture Using Aqueous Amino Acid Solvents in a Crossflow Absorber

Carbon dioxide (CO 2 ) is the most abundant of all greenhouse gases (GHGs). CO 2 levels in the atmosphere are 50% higher than in the preindustrial era, trapping heat. CO 2 removal from the atmosphere by direct air capture (DAC) is needed to achieve the internationally agreed global temperature goals. The most common CO 2 capture technology is absorption by aminebased solvents in packed columns. Amino acid solutions have recently gained attention due to their advantages over traditional amine solvents. To be implemented effectively, DAC industrial processes need to handle large airflow rates in separation absorbers. The large air and solvent flow rates preclude the use of countercurrent columns due to high-pressure drops and the occurrence of flooding. Crossflow air−liquid absorbers are used to handle large air and liquid volumes due to their lower-pressure drop. The objective of this work is to study the influence of crossflow absorber geometric parameters and operating conditions on product formation and process efficiency. An already derived theoretical model for countercurrent absorbers has been modified to simulate the operation of a crossflow DAC absorber. The predictive model was implemented into a computer code that was used to study the efficiency of the processes as geometric equipment dimensions and operating parameters vary. Practical suggestions are made to design more efficient DAC processes.

Absorption↗
DOE OSTI2024

Preparing an on-Demand Cloud Processing Workflow for NISAR Ecosystems Science Products

In preparation for the NISAR launch and data collection in 2024, the NISAR Project Science Team is building workflows for each Science Team discipline (Ecosystems, Cryosphere, and Solid Earth). This abstract focuses on the Ecosystem disciplines and the development of on-demand cloud-processing workflows for wetlands inundation, forest biomass, agricultural active crop area, and forest disturbance. The workflow simulates NISAR data using UAVSAR or ALOS-2 Single Look Complex data, which are processed to Level 2 geocoded polarimetric covariance matrix products using InSAR Scientific Computing Environment 3.0 software and to Level 3 science products using the Algorithm Theoretical Basis Documents. In this presentation, we describe these workflows and efforts to improve efficiency and data accessibility by using a cloud processing system. We present preliminary sample products from each Ecosystem discipline: inundation, forest biomass, crop area, and forest disturbance.

Christensen, Alexandra↗
DOE OSTI2026

Independent and interactive effects of wet bulb globe temperature and air pollution exposures on suicide mortality

Background: Individual components of the ambient environment, such as temperature and air pollution, exist as part of a complex mixture and have been associated with suicide; however, their interactive effects remain poorly understood. This study examined the independent and interactive effects of wet bulb globe temperature (WBGT), nitrogen dioxide (NO 2 ), and fine particulate matter (PM 2.5 ) on suicide mortality. Methods: We identified 7,551 suicide cases in Utah, USA, from 2000 to 2016 and assigned exposure to daily maximum WBGT (sourced from the European Center for Medium-Range Weather Forecasts) and PM 2.5 and NO 2 concentrations (sourced from a national spatiotemporal ensemble model) using decedent’s residential address at the time of death. A case-crossover design with conditional logistic regression was used to estimate the independent and interactive effects of WBGT max , PM 2.5 , and NO 2 on suicide. For exposure windows, we considered single days preceding suicide (lag 0 to 6) and their averages across preceding days (lag 0–1, 0–3, and 0–6). Analyses were stratified by season. Results: We identified a significant association between WBGT max and suicide across all seasons (odds ratio [OR] = 1.05, 95% confidence interval [CI]: 1.01, 1.10; per 5 °C increase on lag 0–3 days). The associations were stronger in the warm season (March 22 to September 21), with ORs and 95% CIs ranging from 1.08 (1.02, 1.15) to 1.20 (1.10, 1.30) per 5 °C increase depending on the lag periods. We observed synergistic interactions between WBGT max and PM 2.5 and NO 2 in the warm season, associated with higher odds of suicide. The associations of WBGT max with suicide were most pronounced at high NO 2 levels. Conclusions: We found evidence of synergistic interactions between WBGT max and PM 2.5 and NO 2 on suicide in the warm season, emphasizing the need for considering the combined effects of heat stress and air pollution in suicide prevention strategies.

Fine particulate matter↗
DOE OSTI2022

Diurnal rainfall response to the physiological and radiative effects of CO 2 in tropical forests in the Energy exascale earth system model v1

Understanding how the connection between rainfall and tropical forests will respond to increasing CO$_2$ concentrations is a key element in understanding how the tropical water cycle will respond to increasing CO$_2$. The plant physiological and radiative impacts of CO$_2$ on rainfall patterns over tropical forest regions are examined in the Energy Exascale Earth System Model version 1.1 (E3SMv1.1-BGC) biogeochemistry experiments. Composite analysis reveals a dampening of the diurnal cycle of rainfall over the Amazon, Congo, and Maritime Continent in response to rising CO$_2$ levels, regardless of the sign of total rainfall change. A full factorial model experiment confirms that the CO$_2$ radiative and CO$_2$ plant physiological effects can individually or jointly reduce the magnitude of the rainfall diurnal cycle, though the physical pathway giving rise to the reduction differs between the two effects. For the physiological response, stomatal closure reduces evapotranspiration, which dries the boundary layer and raises the lifting condensation level. These effects combine to reduce deep convective rainfall during its peak occurrence in the late daytime to early nighttime period. For the radiative response, a relative reduction in daytime CAPE (consistent with a reduction in the diurnal temperature range) leads to less frequent triggering of deep convection and a reduction of rainfall diurnal amplitude. These diurnal rainfall changes are structurally similar across seasons, and show little sensitivity to representation of nutrient coupling for the land biogeochemistry. In agreement with previous findings, the physiological response has only minor impact on extreme rainfall relative to the radiative response.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Plastic Waste Product Captures Carbon Dioxide in Nanometer Pores

We discuss, plastic waste (PW) and increasing atmospheric carbon dioxide (CO 2 ) levels are among the top environmental concerns presently facing humankind. With an ambitious 2050 zero-CO 2 emissions goal, there is a demand for economical CO 2 capture routes. Here we show that the thermal treatment of PW in the presence of potassium acetate yields an effective carbon sorbent with pores width of 0.7–1.4 nm for CO 2 capture. The PW to carbon sorbent process works with single or mixed streams of polyolefin plastics. The CO 2 capacity of the sorbent at 25 °C is 17.0 ± 1.1 wt % (3.80 ± 0.25 mmol g –1 ) at 1 bar and 5.0 ± 0.6 wt % (1.13 ± 0.13 mmol g –1 ) at 0.15 bar, and it regenerates upon reaching 75 ± 5 °C. The CO 2 capture cost from flue gas via this technology is estimated to be <$21 ton –1 CO 2 , much lower than competing CO 2 capture technologies. Hence, this PW-derived carbon material should find utility in the capture of CO 2 from point sources of high CO 2 emissions while providing a use for otherwise deleterious PW.

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2023

Rational design of a genetically encoded NMR zinc sensor

Elucidating the biochemical roles of the essential metal ion, Zn 2+ , motivates detection strategies that are sensitive, selective, quantitative, and minimally invasive in living systems. Fluorescent probes have identified Zn 2+ in cells but complementary approaches employing nuclear magnetic resonance (NMR) are lacking. Recent studies of maltose binding protein (MBP) using ultrasensitive 129 Xe NMR spectroscopy identified a switchable salt bridge which causes slow xenon exchange and elicits strong hyperpolarized 129 Xe chemical exchange saturation transfer (hyper-CEST) NMR contrast. To engineer the first genetically encoded, NMR-active sensor for Zn 2+ , we converted the MBP salt bridge into a Zn 2+ binding site, while preserving the specific xenon binding cavity. The zinc sensor (ZS) at only 1 μM achieved ‘turn-on’ detection of Zn 2+ with pronounced hyper-CEST contrast. This made it possible to determine different Zn 2+ levels in a biological fluid via hyper-CEST. ZS was responsive to low-micromolar Zn 2+ , only modestly responsive to Cu 2+ , and nonresponsive to other biologically important metal ions, according to hyper-CEST NMR spectroscopy and isothermal titration calorimetry (ITC). Protein X-ray crystallography confirmed the identity of the bound Zn 2+ ion using anomalous scattering: Zn 2+ was coordinated with two histidine side chains and three water molecules. Penta-coordinate Zn 2+ forms a hydrogen-bond-mediated gate that controls the Xe exchange rate. Metal ion binding affinity, 129 Xe NMR chemical shift, and exchange rate are tunable parameters via protein engineering, which highlights the potential to develop proteins as selective metal ion sensors for NMR spectroscopy and imaging.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2021

An analytic hybrid halo + perturbation theory model for small-scale correlators: baryons, halos, and galaxies

In this work, we update Halo Zeldovich Perturbation Theory (HZPT, [1]), an analytic model for the two-point statistics of dark matter, to describe halo and galaxy clustering, and galaxy-matter cross-correlation on nonlinear scales. The model correcting Zeldovich has an analytic Fourier transform, and therefore is valid in both configuration space and Fourier space. The model is accurate at the 2%-level or less for P_mm (k< 1 h/Mpc), P_hm (k< 1 h/Mpc), P_hh (k< 2 h/Mpc), P gm (k< 1 h/Mpc), P gg (k< 1 h/Mpc), ξ mm (r> 1 Mpc/h), ξ hm (r> 2 Mpc/h), ξ hh (r> 2 Mpc/h), ξ gm (r> 1 Mpc/h), ξ gg (r> 2 Mpc/h), for LRG-like mock galaxies. We show that the HZPT model for matter correlators can account for the effects of a wide range of baryonic feedback models and provide two extended dark matter models which are of 1% (3%) accuracy for k < 10 (8) h/Mpc. We explicitly model the non-perturbative features of halo exclusion for the halo-halo and galaxy-galaxy correlators, as well as the presence of satellites for galaxy-matter and galaxy-galaxy correlation functions. We perform density estimation using N-body simulations and a wide range of HOD galaxy mocks to obtain correlations of model parameters with the cosmological parameters Ω m and σ 8 . HZPT can provide a fast, interpretable, and analytic model for combined-probe analyses of redshift surveys using scales well into the non-linear regime.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2021

Cdkn1a transcript variant 2 is a marker of aging and cellular senescence

Cellular senescence is a cell fate response characterized by a permanent cell cycle arrest driven primarily the by cell cycle inhibitor and tumor suppressor proteins p16 Ink4a and p21 Cip1/Waf1 . In mice, the p21 Cip1/Waf1 encoding locus, Cdkn1a , is known to generate two transcripts that produce identical proteins, but one of these transcript variants is poorly characterized. We show that the Cdkn1a transcript variant 2, but not the better-studied variant 1, is selectively elevated during natural aging across multiple mouse tissues. Importantly, mouse cells induced to senescence in culture by genotoxic stress (ionizing radiation or doxorubicin) upregulated both transcripts, but with different temporal dynamics: variant 1 responded nearly immediately to genotoxic stress, whereas variant 2 increased much more slowly as cells acquired senescent characteristics. Upon treating mice systemically with doxorubicin, which induces widespread cellular senescence in vivo , variant 2 increased to a larger extent than variant 1. Variant 2 levels were also more sensitive to the senolytic drug ABT-263 in naturally aged mice. Thus, variant 2 is a novel and more sensitive marker than variant 1 or total p21 Cip1/Waf1 protein for assessing the senescent cell burden and clearance in mice.

60 APPLIED LIFE SCIENCES↗
DOE OSTI2020

Observation of Road Salt Aerosol Driving Inland Wintertime Atmospheric Chlorine Chemistry

Inland sources of particulate chloride for atmospheric nitryl chloride (ClNO2) formation remain unknown and unquantified, hindering air quality assessments. Globally each winter, tens of millions of tons of road salt are spread on roadways for deicing. Here, we identify road salt aerosol as the primary chloride aerosol source, accounting for 80–100% of ClNO 2 formation, at an inland urban area in the wintertime. This study provides experimental evidence of the connection between road salt and air quality through the production of this important reservoir for nitrogen oxides and chlorine radicals, which significantly impact atmospheric composition and pollutant fates. A numerical model was employed to quantify the contributions of chloride sources to ClNO 2 production. The traditional method for simulating ClNO 2 considers chloride to be homogeneously distributed across the atmospheric particle population; yet, we show that only a fraction of the particulate surface area contains chloride. Our new single-particle parametrization considers this heterogeneity, dramatically lowering overestimations of ClNO 2 levels that have been routinely reported using the prevailing methods. The identification of road salt as a ClNO 2 source links this common deicing practice to atmospheric composition and air quality in the urban wintertime environment.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2025

Ocean liming effect on a North Atlantic microbial community: changes in composition and rates

The ongoing rise in atmospheric CO 2 levels and the consequent global warming make it increasingly difficult to maintain the global temperature within the 1.5 - 2°C target set by the Paris Agreement. Therefore, strategies to remove carbon dioxide from the atmosphere are being developed, with ocean alkalinity enhancement (OAE) gaining most attention. Within OAE, ocean liming- the addition of quicklime (CaO) or hydrated lime (Ca(OH) 2 )- can not only remove CO 2 from the atmosphere but potentially counteract the effects of ocean acidification. Although quite attractive, these technologies have yet to be tested regarding ecological safety and efficacy. Here we report the impacts of ocean liming on the abundance, composition and extracellular enzymatic activity (EEA) rates of a North Atlantic planktonic community. The results demonstrate that OAE led to a decreased phytoplankton development, mainly diatoms. The bacterial response to OAE was community-specific, with a consistent increase in the relative abundance of the order Oceanospirillales. OAE also led to increased EEA rates, especially within the bacterial community. These findings suggest that while initial effects on phytoplankton may be limited, the specific impacts on bacterial groups suggest that OAE could influence the remineralization of organic matter. If our results apply to other communities, OAE might initially affect marine microbial dynamics, but further studies are needed to determine if these effects are long-term.

16S↗
DOE OSTI2020

A phytophotonic approach to enhanced photosynthesis

Photosynthesis is the dominant biotic carbon sink on earth and hence presents an opportunity for enhanced sequestration of CO 2 . If the average net carbon fixation efficiency of terrestrial plants could be increased by 3.3%, all anthropogenic CO 2 accumulating in the atmosphere could instead be reduced and incorporated into terrestrial biomass. Plants make inefficient use of the overly abundant sunlight available to them, a result of having evolved to be competitive and survive highly dynamic environmental conditions rather than maximize photosynthetic productivity. We explore herein a phytophotonic approach to enhanced photosynthesis, whereby sunlight is redistributed by means of luminescent or persistent luminescent (PersL) materials. Phytophotonics has potential at varied scales, ranging from photobioreactors to greenhouses all the way to crops in the field, the latter having the potential to impact planetary CO 2 levels. The approach is three-fold: a spectral redistribution to relieve high-light-stress at the top surface of leaves and increasingly drive photosynthesis deeper in leaves and canopies; a minute-scale temporal redistribution to bridge periods of intermittent shade and reduce shock associated with variable light conditions; and a multiple-hour temporal redistribution to shift a fraction of high-intensity midday lighting to evening hours. Based on simulations of photoluminescent materials and light quality experiments with a model algal system, it is shown that while lengthening daylight hours will require significant improvements in PersL materials, the other two approaches show more immediate promise. We demonstrate a means of concentrating PersL light from SrAl 2 O 4 :Eu,Dy, approaching levels needed to effectively bridge periods of natural shade, and outline the scientific questions and technical hurdles remaining to realize the benefits of the proposed spectral shift.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2020

Metabolic Profiling Reveals Biochemical Pathways Responsible for Eelgrass Response to Elevated CO2 and Temperature

Abstract As CO 2 levels in Earth’s atmosphere and oceans steadily rise, varying organismal responses may produce ecological losers and winners. Increased ocean CO 2 can enhance seagrass productivity and thermal tolerance, providing some compensation for climate warming. However, the metabolic shifts driving the positive response to elevated CO 2 by these important ecosystem engineers remain unknown. We analyzed whole-plant performance and metabolic profiles of two geographically distinct eelgrass ( Zostera marina L.) populations in response to CO 2 enrichment. In addition to enhancing overall plant size, growth and survival, CO 2 enrichment increased the abundance of Calvin Cycle and nitrogen assimilation metabolites while suppressing the abundance of stress-related metabolites. Overall metabolome differences between populations suggest that some eelgrass phenotypes may be better suited than others to cope with an increasingly hot and sour sea. Our results suggest that seagrass populations will respond variably, but overall positively, to increasing CO 2 concentrations, generating negative feedbacks to climate change.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2024

Ultraviolet H 2 luminescence in molecular clouds induced by cosmic rays

Context. Galactic cosmic rays (CRs) play a crucial role in ionisation, dissociation, and excitation processes within dense cloud regions where UV radiation is absorbed by dust grains and gas species. CRs regulate the abundance of ions and radicals, leading to the formation of more and more complex molecular species, and determine the charge distribution on dust grains. A quantitative analysis of these effects is essential for understanding the dynamical and chemical evolution of star-forming regions. Aims. The CR-induced photon flux has a significant impact on the evolution of the dense molecular medium in its gas and dust components. This study evaluates the flux of UV photons generated by CRs to calculate the photon-induced dissociation and ionisation rates of a vast number of atomic and molecular species, as well as the integrated UV photon flux. Methods. To achieve these goals, we took advantage of recent developments in the determination of the spectra of secondary electrons, in the calculation of state-resolved excitation cross sections of H 2 by electron impact, and of photodissociation and photoionisation cross sections. Results. We calculated the H 2 level population of each rovibrational level of the X, B, C, B′, D, B″, D′, and a states. We then computed the UV photon spectrum of H 2 in its line and continuum components between 72 and 700 nm, with unprecedented accuracy, as a function of the CR spectrum incident on a molecular cloud, the H 2 column density, the isomeric H 2 composition, and the dust properties. The resulting photodissociation and photoionisation rates are, on average, lower than previous determinations by a factor of about 2, with deviations of up to a factor of 5 for the photodissociation of species such as AlH, C 2 H 2 , C 2 H 3 , C 3 H 3 , LiH, N 2 , NaCl, NaH, O 2 + , S2, SiH, l-C 4 , and l-C 5 H. A special focus is given to the photoionisation rates of H 2 , HF, and N 2 , as well as to the photodissociation of H 2 , which we find to be orders of magnitude higher than previous estimates. We give parameterisations for both the photorates and the integrated UV photon flux as a function of the CR ionisation rate, which implicitly depends on the H 2 column density, as well as the dust properties.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2024

Ultraviolet H 2 luminescence in molecular clouds induced by cosmic rays

Context. Galactic cosmic rays (CRs) play a crucial role in ionisation, dissociation, and excitation processes within dense cloud regions where UV radiation is absorbed by dust grains and gas species. CRs regulate the abundance of ions and radicals, leading to the formation of more and more complex molecular species, and determine the charge distribution on dust grains. A quantitative analysis of these effects is essential for understanding the dynamical and chemical evolution of star-forming regions. Aims. The CR-induced photon flux has a significant impact on the evolution of the dense molecular medium in its gas and dust components. This study evaluates the flux of UV photons generated by CRs to calculate the photon-induced dissociation and ionisation rates of a vast number of atomic and molecular species, as well as the integrated UV photon flux. Methods. To achieve these goals, we took advantage of recent developments in the determination of the spectra of secondary electrons, in the calculation of state-resolved excitation cross sections of H 2 by electron impact, and of photodissociation and photoionisation cross sections. Results. We calculated the H 2 level population of each rovibrational level of the X, B, C, B', D, B", D', and a states. We then computed the UV photon spectrum of H 2 in its line and continuum components between 72 and 700 nm, with unprecedented accuracy, as a function of the CR spectrum incident on a molecular cloud, the H 2 column density, the isomeric H 2 composition, and the dust properties. The resulting photodissociation and photoionisation rates are, on average, lower than previous determinations by a factor of about 2, with deviations of up to a factor of 5 for the photodissociation of species such as AlH, C 2 H 2 , C 2 H 3 , C 3 H 3 , LiH, N 2 , NaCl, NaH, O$^+_2$, S 2 , SiH, l-C 4 , and l-C 5 H. A special focus is given to the photoionisation rates of H 2 , HF, and N 2 , as well as to the photodissociation of H 2 , which we find to be orders of magnitude higher than previous estimates. We give parameterisations for both the photorates and the integrated UV photon flux as a function of the CR ionisation rate, which implicitly depends on the H 2 column density, as well as the dust properties.

79 ASTRONOMY AND ASTROPHYSICS↗
DOE OSTI2020

P-Type Electrochemical Doping Can Occur by Cation Expulsion in a High Performing Polymer for Organic Electrochemical Transistors

We investigate the mechanism of ion-dependent charge compensation during electrochemical oxidation (doping) of the model mixed ionic/electronic transporting polythiophene derivative poly(3-{[2-(2-methoxyethoxy)ethoxy]methyl}thiophene-2,5-diyl) (P3MEEMT). Using a combination of electrochemical quartz microbalance gravimetry and glow discharge optical emission spectroscopy, we show that charge compensation during polymer redox processes proceeds via a cation-dependent mechanism. For p-type polymer oxidation in certain electrolytes, charge compensation is achieved by both eventual injection of anions into the film, as well as initial expulsion of cations from the film. We compare doping mechanisms for a variety of electrolyte salts including potassium chloride, tetrabutylammonium chloride, potassium hexafluorophosphate (KPF6), and tetrabutylammonium hexafluorophosphate. For the electrolyte KPF6, both the cations and anions coexist in the water-swelled polymer even prior to application of electrical bias. Our data indicate that electrochemical doping (hole injection into the polymer and ionic charge compensation) proceeds via the following mechanism: (1) hydration of the neutral film by electrolyte (water, cations, anions), (2) cation (K+) expulsion from the film upon initial application of an oxidative bias, and (3) anion injection into the film at higher oxidation/doping levels (>~2 × 1020/cm3). Understanding the mechanism of charge compensation during the doping process should allow for the design of improved mixed ionic/electronic conductors for use in applications ranging from organic supercapacitors and redox flow batteries to bioelectronic sensors, thermoelectrics, and devices for neuromorphic computing.

Flagg, Lucas Q.↗
DOE OSTI2025

Techno-economic evaluation of emission control configurations for AMP/PZ-based post-combustion CO 2 capture

Minimizing the environmental impacts of amine-based post-combustion carbon capture technologies is essential for regulatory compliance and public acceptance. Experimental campaigns at RWE's CO 2 capture pilot plant in Niederaussem using CESAR1 demonstrated that combining existing emission abatement technologies can substantially reduce the concentration of amines and degradation products in the CO 2 -depleted flue gas to below the detection limit of an infrared spectrometer. The campaign confirmed that a proprietary dry bed technology (OEASE aerozone™) or a second water wash can reduce AMP and PZ emissions to below 1 mg/Nm 3 . However, an acid or chemically active wash downstream of the water wash is necessary to reduce NH 3 emissions to very low levels (<2 mg/Nm 3 ). Combining a dry bed with an acid wash significantly reduces both the required acid solution and the resulting acid waste. The techno-economic analysis indicates that implementing emission mitigation technologies provides substantial environmental benefits for the CESAR1 process, with only a marginal increase (<1 €/tCO 2 ) in both the carbon capture cost (CCC) and CO 2 avoidance cost (CAC). The additional capital cost associated with extra column packing is offset by operational cost savings from reduced solvent losses. For stringent emission permits targeting NH 3 , a configuration combining a dry bed upstream of the water wash followed by an acid wash achieves the best balance between emission control and cost efficiency. This configuration results in a Levelized Cost of Electricity (LCOE) of 143 €/MWh, a CCC of 45.4 €/tCO 2 , and a CAC of 88.4 €/tCO 2 .

AMP↗
DOE OSTI2021

Diel Transcriptional Oscillations of a Plastid Antiporter Reflect Increased Resilience of Thalassiosira pseudonana in Elevated CO 2

Acidification of the ocean due to high atmospheric CO 2 levels may increase the resilience of diatoms causing dramatic shifts in abiotic and biotic cycles with lasting implications on marine ecosystems. Here, we report a potential bioindicator of a shift in the resilience of a coastal and centric model diatom Thalassiosira pseudonana under elevated CO 2 . Specifically, we have discovered, through EGFP-tagging, a plastid membrane localized putative Na + (K + )/H + antiporter that is significantly upregulated at >800 ppm CO 2 , with a potentially important role in maintaining pH homeostasis. Notably, transcript abundance of this antiporter gene was relatively low and constant over the diel cycle under contemporary CO 2 conditions. In future acidified oceanic conditions, dramatic oscillation with >10-fold change between nighttime (high) and daytime (low) transcript abundances of the antiporter was associated with increased resilience of T. pseudonana. By analyzing metatranscriptomic data from the Tara Oceans project, we demonstrate that phylogenetically diverse diatoms express homologs of this antiporter across the globe. We propose that the differential between night- and daytime transcript levels of the antiporter could serve as a bioindicator of a shift in the resilience of diatoms in response to high CO 2 conditions in marine environments.

59 BASIC BIOLOGICAL SCIENCES↗