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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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At least 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1996

The Metabolic World: Sugars as an Energized Carbon Substrate for Prebiotic and Biotic Synthesis

To understand the origin of metabolism and biopolymer synthesis we investigated the energy sources that drive anabolic metabolism. We found that biosynthesis of amino acids and lipids from sugars is driven bz the free energy of redox disproportionation of carbon (see discussion or next page). The indispensable role of sugar disproportionation in the biosynthesis of amino acids and lipids suggests that the origin of life uses the same chemical engine, and was therefore based on nonenzymatic redox disproportionation reactions of sugars that occurred in the presence o ammonia and hydrogen sulfide. The chemistry of this 'metabolic' model of the origin of life is described.

Weber, Arthur L.↗
DOE OSTI2020

Formation and transformation of manganese(III) intermediates in the photochemical generation of manganese(IV) oxide minerals

As important natural oxidants and adsorbents, manganese (Mn) oxide minerals affect the speciation, bioavailability and fate of pollutants and nutrient elements. It was found that birnessite-type Mn(IV) oxide minerals can be formed in the presence of NO 3 – and solar irradiation. However, the photochemical formation and transformation processes from Mn 2+ to Mn(IV) oxide minerals remain unclear. In this work, the Mn(IV) oxide minerals were confirmed to be photochemically formed mainly due to the disproportionation of Mn(III) intermediates generated from the oxidation of Mn 2+ in the presence of NO 3 – under UV light irradiation. The oxidation rate of Mn 2+ to Mn(IV) oxide minerals decreased with increasing initial Mn 2+ concentration due to the lower disproportionation rate. The increase in NO 3 – concentration, pH and temperature promoted Mn 2+ photochemical oxidation. The photochemical formation rate of Mn(IV) oxide minerals increased with increasing ligand concentrations at low ligand concentrations. Ligands affected the formation of Mn(IV) oxide minerals by promoting the formation and reducing the reactivity of Mn(III) intermediates. Altogether, this work reveals the important role of Mn(III) intermediates in the formation of natural Mn oxide minerals.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Effect of processing hydrogen pressure on magnetic properties of HDDR Nd-Fe-B magnet

High coercivity and anisotropic Nd-Fe-B powders for making anisotropic bonded magnets have been prepared by hydrogenation-disproportionation-desorption-recombination (HDDR). In this work, we found that the processing hydrogen pressure is intimately correlated with the formation of c-axis crystal texture of Nd 2 Fe 14 B phase. There exists a critical hydrogen pressure, P crit , during hydrogen-disproportionation stage, that promotes the formation of c-axis crystal texture. When processing hydrogen pressure is higher than P crit , the formation of c-axis texture deteriorates and results in isotropic Nd-Fe-B magnetic powders. The existence of P crit is ascribed to the thermodynamics and kinetics origin during HDDR process.

36 MATERIALS SCIENCE↗
DOE OSTI2020

A lithium-sulfur battery with a solution-mediated pathway operating under lean electrolyte conditions

Lithium-sulfur (Li-S) battery is one of the most promising candidates for the next generation energy storage systems. However, several barriers, including polysulfide shuttle effect, the slow solid-solid surface reaction pathway in the lower discharge plateau, and corrosion of Li anode still limit its practical applications, especially under the lean electrolyte condition required for high energy density applications. Here, we propose a solution-mediated sulfur reduction pathway to improve the capacity and reversibility of the sulfur cathode and suppress dendrite growth on the Li metal anode simultaneously. With this method, a high coulombic efficiency (99%) and stable cycle life over 100 cycles were achieved under application-relevant conditions (S loading: 6.2 mg cm-2; electrolyte to sulfur ratio: 3 mLE gs-1; sulfur weigh ratio: 72 wt%). This result is enabled by a specially designed Li2S4-rich electrolyte, in which Li2S is formed through a chemical disproportionation reaction instead of electrochemical routes. A diglyme solvent was used to obtain electrolytes with the optimum range of Li2S4 concentration. Operando X-ray absorption spectroscopy confirms the solution pathway in a practical Li-S cell. This solution pathway not only introduces a new electrolyte regime for practical Li-S batteries, but also provides a new perspective for bypassing the inefficient surface pathway for other electrochemical processes.

Wang, Hui↗
DOE OSTI2026

Wildfire-Power Grid Interactions: Feedback, Impacts, Monitoring, Modeling, and Mitigation Strategies

Wildfires are increasingly interacting with electric power systems through a two-way hazard chain: fires damage grid assets and trigger cascading outages, while grid faults can ignite new fires under hot, dry, and windy conditions. This review synthesizes the state of knowledge across five domains: (i) physical impacts of flames, heat, and smoke on lines, towers, insulators, and substations; (ii) power-infrastructure-initiated ignitions via conductor clash, high-impedance faults, and corona discharge; (iii) widespread blackouts and disproportionate societal impacts; (iv) multi-scale monitoring spanning laboratory tests, in-situ and grid-integrated sensors, and Earth observation; (v) coupled modeling that links fire behavior with grid operations; and (vi) technological and strategic mitigation pathways spanning prevention, response, and recovery. We integrate these domains into a novel 'feedback-aware' socio-technical framework. Through a longitudinal analysis (2005-2025) of global incidents, we identify that while vegetation contact remains the most frequent ignition source, aging infrastructure failure has emerged as a critical driver of catastrophic 'mega-fires'. We further identify persistent gaps, including limited interoperability of high-frequency grid and environmental data, scarce real-time data assimilation, and under-developed equity metrics for outage management. We conclude by outlining a research agenda to (1) deploy interoperable sensing architectures, (2) advance feedback-coupled fire-grid simulations, and (3) evaluate mitigation portfolios through techno-economic and fairness lenses. Recognizing wildfire-grid interactions as coupled socio-technical systems is essential for protecting infrastructure and communities and for ensuring reliable, sustainable electricity in a changing world.

24 POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2025

Ligand Hole Driven Metal–Insulator Transition Exemplified in a Layered Transition Metal Oxide

The interplay of cooperative Jahn–Teller (JT) distortions and charge-disproportionation (CD) with a strong electronic correlation in transition metal oxides leads to structural symmetry breaking. Both JT and CD often manifest in the form of significant modifications in electronic and structural properties such as band splitting, metal–insulator transitions (MIT), and enhanced electron lattice interactions. Notably, the charge-disproportionation is a key electronic feature that drives the MIT. Here, we demonstrate and quantify it using first-principles calculations combining density-functional theory, dynamical mean-field theory, and spin–lattice Monte Carlo simulations. Taking Ca 2 FeMnO 6 as a prototypical example of a correlated oxide, our ab initio study shows that MIT in Ca 2 FeMnO 6 arises from the partial localization of oxygen ligand holes at alternate Fe sites that control both charge and magnetic ordering. Interestingly, the band gap was found to be fundamentally controlled by the strength of the charge-transfer energy and not by the Mott–Hubbard interactions. The novel physics and insights presented in this work reveal promising routes for tuning the electronic functionality in transition-metal oxides.

36 MATERIALS SCIENCE↗
DOE OSTI2021

Cis-Divacant Octahedral Fe(II) in a Dimensionally Reduced Family of 2-(Pyridin-2-yl)pyrrolide Complexes

Four-coordinate transition metal complexes can adopt a diverse array of coordination geometries, with square planar and tetrahedral coordination being the most prevalent. Previously, we reported the synthesis of a trinuclear Fe(II) complex, Fe 3 TPM 2 , supported by a three-fold symmetric 2-pyridylpyrrolide ligand (i.e., tris(5-(pyridin-2-yl)-1H-pyrrol-2-yl)methane), that featured a rare cis-divacant octahedral (CDO) geometry at each Fe(II) center. Here, a series of truncated 2-pyridylpyrrolide ligands is described that support mono- and binuclear Fe(II) complexes that also exhibit CDO geometries. Metallation of tetradentate ligand bis(5-(pyridin-2-yl)-1H-pyrrol-2-yl)methane (H 2 BPM) in THF results in a binuclear complex Fe 2 (BPM) 2 (THF) 2 in which both Fe(II) ions are octahedrally coordinated. The coordinated THF solvent ligands are labile: THF dissociation leads to Fe 2 (BPM) 2 , which features five-coordinate Fe(II) ions. The Fe–Fe distance in these binuclear complexes can be elongated by ligand methylation. Metalation of bis(5-(6-methylpyridin-2-yl)-1H-pyrrol-2-yl)methane (H 2 BPM Me ) in THF leads to the formation of four-coordinate, CDO Fe(II) centers in Fe(BPM Me ) 2 . Further ligand truncation affords bidentate ligands 2-(1H-pyrrol-2-yl)pyridine (PyrPyrrH) and 2-methyl-6-(1H-pyrrol-2-yl)pyridine (Pyr Me PyrrH). Metalation of these ligands in THF affords six-coordinate complexes Fe(PyrPyrr) 2 (THF) 2 and Fe(Pyr Me Pyrr) 2 (THF) 2 . Dissociation of labile solvent ligands provides access to fourcoordinate Fe(II) complexes. Ligand disproportionation at Fe(PyrPyrr) 2 results in the formation of Fe(PyrPyrr) 3 and Fe(0). Ligand methylation suppresses this disproportionation and enables isolation of Fe(Pyr Me Pyrr) 2 , which is rigorously CDO. Complete ligand truncation, by separating the 2-pyridylpyrrolide ligands into the constituent monodentate pyridyl and pyrrolide donors, affords Fe(Pyr) 2 (Pyrr) 2 in which the Fe(II) is tetrahedrally coordinated. Computational analysis indicates that the potential energy surface that dictates the coordination geometry in this family of four-coordinate complexes is fairly flat in the vicinity of CDO coordination. Furthermore, these synthetic studies provide the structural basis to explore the implications of CDO geometry on Fe-catalyzed reactions.

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

Role of Axial Ligation in Gating the Reactivity of Dimethylplatinum(III) Diimine Radical Cations

Electrochemical methods are coupled with chemical oxidant-based analytical strategies to evaluate the oxidative reactivity of the platinum(II) diimine complex (bpy)Pt II (CH 3 ) 2 (bpy = 2,2'-bipyridine) in coordinating and non-coordinating media. Through this mechanistic analysis, we show that the one-electron oxidation of (bpy)Pt II (CH 3 ) 2 generates a highly reactive, 15-electron Pt III radical cation and identify three reaction pathways that can follow this oxidation: radical–substrate dimerization, radical-radical dimerization, and oxidative disproportionation. Axial ligation of the initially generated [(bpy)Pt III (CH 3 ) 2 ] •+ species is a critical driver of this reactivity, gating the available mechanistic pathways and tuning the competition between radical–radical dimerization and oxidative disproportionation.

14 SOLAR ENERGY↗
DOE OSTI2020

Mechanism of the Accelerated Water Formation Reaction under Interfacial Confinement

Subnanoscale spaces at the interface between weakly coupled thin films and their metal supports offer exciting opportunities for studying chemical reactions under confinement. Here, we investigated the kinetics of water formation (from hydrogen and chemisorbed oxygen) in the confined space at the interface between bilayer (BL) silica and a Ru(0001) support, compared to the reaction on the bare Ru(0001) surface. Ambient pressure X-ray photoelectron spectroscopy (AP-XPS) experiments were carried out at different temperatures at elevated pressures of H 2 to follow the reaction kinetics. The apparent activation energy at the BL-silica/Ru(0001) interface was found to be 0.38 eV lower than that on bare Ru(0001), consistent with a recent report by Prieto et al. (Angew. Chem., Int. Ed.2018, 57(28), 8749–8753) carried out at lower H 2 pressures using low-energy electron microscopy. Density functional theory calculations revealed that the rate-limiting step in the direct hydrogenation pathway on the Ru(0001) surface is the first hydrogen addition step (*H + *O ↔ *OH). The confinement at the BL-silica/Ru(0001) interface only marginally affects the energy barrier of the first hydrogen addition. Instead, it activates an alternative disproportionation reaction pathway (*H 2 O + *O ↔ 2*OH). On the bare Ru(0001) surface, the disproportionation pathway can only occur at cryogenic temperatures or under high water vapor pressures. However, the presence of the BL-silica increases the desorption barrier for water molecules at the interface. The increased residence time allows trapped water molecules to react with chemisorbed oxygen to produce two *OH per H 2 O with an activation energy 0.25 eV lower than that of the first hydrogen addition step. Finally, this work reveals the origin of the observed accelerated water formation reaction at the BL-silica/Ru(0001) interface in the low-temperature regime (T < 350 K) and points to a route to engineer chemical reaction pathways by leveraging subnanoscale confined spaces at metal–oxide interfaces.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Deciphering the Mechanism of Base-Triggered Conversion of Ammonia to Molecular Nitrogen and Methylamine to Cyanide

Here we report an in-depth investigation into the ammonia oxidation mechanism by the catalyst [Ru III (tpy)(dmabpy)NH 3 ] 3 + ([Ru(NH 3 )] 3 + ). Stoichiometric reactions of [Ru(NH 3 )] 3 + were carried out with exogenous noncoordinating bases to trigger a proposed redox disproportionation reaction, which was followed using variable-temperature NMR spectroscopy. An intermediate species was identified as a dinitrogen-bridged complex using 15 N NMR and Raman spectroscopy on isotopically labeled complexes. This intermediate is proposed to derive from coupling of nitridyl species formed upon sequential redox disproportion reactions. Acetonitrile displaces the dinitrogen bridge to yield free N 2 . DFT calculations support this lower-energy pathway versus that previously reported for ammonia oxidation by the parent [Ru III (tpy)(bpy)NH 3 ] 3 + complex. These experimental and computational results are consistent with the interpretation of redox disproportionation involving sequential hydrogen atom transfer reactions by an amide/aminyl intermediate, [Ru(NH 2 ) – ] + $\Leftrightarrow$ [Ru(NH 2 ) • ] + , formed upon deprotonation of the parent complex. Control experiments employing a large excess of ammonia as a base indicate this new proposed lower-energy pathway contributes to the oxidation of ammonia to dinitrogen in conditions relevant to electrocatalysis. In addition, analogous methylamine complexes, [Ru(NH 2 CH 3 )] 2 + /3 + , were prepared to further test the proposed mechanism. Treating [Ru(NH 2 CH 3 )] 3 + with a base cleanly yields two products [Ru(NH 2 CH 3 )] 2 + and [Ru(CN)] + in an ~3:1 ratio, fully consistent with the proposed cascade of hydrogen atom transfer reactions by an intermediate.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

An Experimental and Theoretical Study of the High Temperature Reactions of the Four Butyl Radical Isomers

The high temperature gas phase chemistry of the four butyl radical isomers (n-butyl,sec-butyl, iso-butyl, andtert-butyl) was investigated in a combined experimental and theoretical study. Organic nitrites were used as convenient and clean sources of each of the butyl radical isomers. Rate coefficients for dissociation of each nitrite were obtained experimentally and are at, or close to, the high pressure limit. Low pressure experiments were performed in a diaphragmless shock tube with laser schlieren densitometry at post-shock pressures of 65, 130, and 260 Torr and post-shock temperatures of 700-1000 K. Additional experiments were conducted with iso-butyl radicals at 805 K and 8.7 bar to elucidate changes in mechanism at higher pressures. These experiments were performed in a miniature shock tube with synchrotron-based photoionization mass spectrometry. The mass spectra confirmed that scission of the O-NO bond is the primary channel by which the precursors dissociate, but they also provided evidence of a minor channel (<7.7%) through HNO loss and formation of an aldehyde. These high pressure experiments were also used to determine the disproportionation/recombination ratio for iso-butyl radicals as 0.3. Reanalysis of the lower-temperature literature and the present data yielded rate constants for the disproportionation reaction, iso-butyl + iso-butyl = iso-butene + iso-butane. A chemical kinetics model was developed for the reactions of the butyl isomers that included new paths for highly energized adducts. These adducts are formed by the addition of H, CH 3 or C 2 H 5 to the butyl radicals. Accompanying theoretical investigations show that chemically activated pathways are competitive with stabilization of the adduct by collision under the conditions of the laser schlieren experiments. These calculations also show that at 10 bar and T< 1000 K stabilization is the only important reaction, but at higher temperatures, even at 10 bar, chemically activated product channels should also be considered. Branching fractions and rate coefficients are presented for these reactions. Furthermore, this study also highlights the importance of the radical structure for determining branching ratios for disproportionation and recombination of alkyl radicals, and these were facilitated by theoretical calculations of recombination rate coefficients for the four butyl radical isomers. Overall, the results reveal previously unknown features of butyl radical chemistry under conditions that are relevant to a wide range of applications and reaction mechanisms are presented that incorporate pressure dependent rate coefficients for the key steps.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2020

Adsorption and reaction of methanol on Fe 3 O 4 (001)

The interaction of methanol with iron oxide surfaces is of interest due to its potential in hydrogen storage, and from a fundamental perspective as a chemical probe of the reactivity. We present here a study examining the adsorption and reaction of methanol on magnetite Fe 3 O 4 (001) at cryogenic temperatures using a combination of temperature programmed desorption, x-ray photoelectron spectroscopy, and scanning tunneling microscopy. We report the methanol desorption profile from Fe 3 O 4 (001) is complex, exhibiting peaks at 145, 175, 238, and 273 K, corresponding to the desorption of intact methanol, as well as peaks at 350 and 500 K due to the reaction of methoxy intermediates. The saturation of a monolayer of methanol corresponds to ~5 molecules/unit cell (u.c.), which is slightly higher than the number of surface octahedral iron atoms of 4/u.c. We probe the kinetics and thermodynamics of the desorption of molecular methanol using inversion analysis. The deconvolution of the complex desorption profile into individual peaks allows for calculations of both the desorption energy and the prefactor of each feature. The initial 0.7 methanol/u.c. reacts to form a methoxy and hydroxy intermediates by 180 K, which remains on the surface above room temperature after intact methanol has desorbed. The methoxy species react via one of two channels, a recombination reaction with surface hydroxyls to form additional methanol at ~350 K, and a disproportionation reaction to form methanol and formaldehyde at ~500 K. Only 20% of the methoxy species undergo the disproportionation reaction, with most of them reacting via the 350 K pathway.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2026

Analyzing Land Characteristics Associated with Historical Large-Scale Solar Photovoltaic Deployment in the United States

Large-scale solar (LSS) deployment has accelerated rapidly across the United States, yet comprehensive understanding of its siting patterns remains limited. Here, we present a national-scale geospatial assessment of land characteristics converted for LSS development and apply statistical analyses to evaluate whether installations are disproportionately concentrated within specific land types. We find that siting patterns are strongly correlated with high solar irradiance, underscoring the role of resource quality in shaping deployment decisions. LSS projects are disproportionately concentrated on agricultural lands and shrubland. Within agricultural areas, installations predominantly occur on croplands and are strongly associated with irrigated systems. Notably, more than 90% of projects are deployed on agricultural land with Productive, Versatile, and Resilient (PVR) index values of land quality exceeding the national median. These findings highlight the need for strategic siting frameworks that reconcile solar development with the conservation of agriculturally valuable land.

14 SOLAR ENERGY↗
DOE OSTI2026

Small Co-doping induced magnetic and electrical transitions in single crystal CaF⁢e 0.95 ⁢C⁢o 0.05 ⁢O 3

CaFe⁢O 3 and CaF⁢e 0.95 ⁢C⁢o 0.05 ⁢O 3 single crystals were grown by combing floating-zone method with high oxygen pressure treatment. Both crystals show charge disproportionation of Fe (F⁡e 4+ → F⁡e 3+ + F⁡e 5+ ) accompanied by a metal-to-insulator transition as well as a crystal structural transformation from Pbnm to 𝑃⁢2 1 /𝑛. However, the slight introduction of Co significantly suppresses the critical temperature of charge disproportionation from 290 K in CaFe⁢O 3 to 260 K in CaF⁢e 0.95 ⁢C⁢o 0.05 ⁢O 3 . Different from the single antiferromagnetic phase transition as observed in the polycrystalline CaFe⁢O 3 , two sequential antiferromagnetic transitions are found to occur in these two single crystals with the Néel temperatures around 119 and 112 K for CaFe⁢O 3 crystal and 109 and 98 K for CaF⁢e 0.95 ⁢C⁢o 0.05 ⁢O 3 crystal, respectively. Neutron diffraction illustrates the formation of a spiral antiferromagnetic structure. Moreover, as the temperature further decreases to 65 K, a third magnetic transition accompanied by a second electrical transition is observed in the slightly Co-doped CaF⁢e 0.95 ⁢C⁢o 0.05 ⁢O 3 crystal. In conclusion, first-principles calculations suggest that the introduction of a moderate amount of Co and the peculiar spiral spin texture play an important role in the presence of such new magnetic and electrical transitions.

Xia, Hailiang [Chinese Academy of Sciences (CAS), ↗
DOE OSTI2025

Geographic, sectoral, and constituent characteristics of US off‐site manufacturing wastewater disposal

This study employs recent US Environmental Protection Agency off-site manufacturing wastewater disposal data and a socioenvironmental assessment tool for the United States to understand the characteristics of such disposal in terms of geography, major contributing sectors and pollutants, and environmental impacts. Environmental impact analyses of manufacturing are insufficient without encompassing the extended physical boundary of waste management. Our analysis reveals that off-site manufacturing wastewater disposal occurs disproportionately in populations residing in census tracts already negatively impacted by environmental hazards (impacted populations, or IPs) with 44% of transfers and 55% of Risk Screening Environmental Indicators (RSEI) Hazard going to these areas, compared to their national share of 37%. Disposal hazard is concentrated in a small number of populations, with a Gini coefficient of 0.99 for RSEI Hazard. Four manufacturing sub-sectors are significant generators: Chemicals, Fabricated Metals, Primary Metals, and Transportation Equipment, with Chemicals off-site wastewater disposal largely occurring in IPs. For individual contaminants, chromium compounds and chromium represent more than 85% of the hazard but less than 10% of transfers. We explore transfer distances and waste generation and disposal hotspots, finding that the Midwest hosts a disproportionate share of off-site wastewater disposal. Further, RSEI Hazard steeply rises at shorter distances and plateaus over distances >500 miles, revealing opportunities to reduce hazard by reducing 20–500-mile transfers. Our findings strongly support targeted mitigation strategies like process substitutions, control technologies, on-site recycling and treatment, and minimizing transfer distances. This article met the requirements for a gold-gold JIE data openness badge described at http://jie.click/badges.

Fuchs, Heidi [Lawrence Berkeley National Laborator↗
DOE OSTI2023

Justice 40 Tool (J40 Tool) v1.0

The Justice 40 tool provides a quantitative framework to support decision-making around equitable energy interventions at the community level. The tool calculates the optimal portfolio of policy interventions that explicitly mitigates energy insecurity of an eligible population, by reducing its disproportionate energy burden. The place-based analysis assumes a spatial census tract-level resolution and distinguishes different sociodemographic groups within each tract. Instead of focusing on a specific technology, the underlying J40 model captures the combined effect of a set of policy interventions, currently including weatherization, rooftop solar, community solar and community wind. For each tract, the model chooses the optimal (least cost) combination of interventions to address the disproportionate burden, considering the specific population demographics and techno-economic potentials of technologies. Mathematically, this problem is formalized as an optimization model and formulated as a linear program.

Heleno, Miguel↗
DOE OSTI2022

Utilizing Novel Field and Data Exploration Methods to Explore Hot Moments in High-Frequency Soil Nitrous Oxide Emissions Data: Opportunities and Challenges

Soil nitrous oxide (N 2 O) emissions are an important driver of climate change and are a major mechanism of labile nitrogen (N) loss from terrestrial ecosystems. Evidence increasingly suggests that locations on the landscape that experience biogeochemical fluxes disproportionate to the surrounding matrix (hot spots) and time periods that show disproportionately high fluxes relative to the background (hot moments) strongly influence landscape-scale soil N 2 O emissions. However, substantial uncertainties remain regarding how to measure and model where and when these extreme soil N 2 O fluxes occur. High-frequency datasets of soil N 2 O fluxes are newly possible due to advancements in field-ready instrumentation that uses cavity ring-down spectroscopy (CRDS). Here, we outline the opportunities and challenges that are provided by the deployment of this field-based instrumentation and the collection of high-frequency soil N 2 O flux datasets. While there are substantial challenges associated with automated CRDS systems, there are also opportunities to utilize these near-continuous data to constrain our understanding of dynamics of the terrestrial N cycle across space and time. Finally, we propose future research directions exploring the influence of hot moments of N 2 O emissions on the N cycle, particularly considering the gaps surrounding how global change forces are likely to alter N dynamics in the future.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2023

Development of a Heavy-Duty Electric Vehicle Integration and Implementation (HEVII) Tool

As demand for consumer electric vehicles (EVs) has drastically increased in recent years, manufacturers have been working to bring heavy-duty EVs to market to compete with Class 6-8 diesel-powered trucks. Many high-profile companies have committed to begin electrifying their fleet operations, but have yet to implement EVs at scale due to their limited range, long charging times, sparse charging infrastructure, and lack of data from in-use operation. Thus far, EVs have been disproportionately implemented by larger fleets with more resources. To aid fleet operators, it is imperative to develop tools to evaluate the electrification potential of heavy-duty fleets. However, commercially available tools, designed mostly for light-duty vehicles, are inadequate for making electrification recommendations tailored to a fleet of heavy-duty vehicles. The main challenge is that light-duty tools do not estimate real-time vehicle mass, a factor that has a disproportionate impact on the energy consumption of large commercial vehicles. The Heavy-Duty Electric Vehicle Integration and Implementation (HEVII) tool advances the state of the art in evaluating electrification potential and infrastructure requirements for fleets of commercial vehicles. In this work, the HEVII tool is demonstrated with non-uniformly sampled telematics data from an existing fleet to assess the suitability for electrification of each individual vehicle, determine optimal locations for charging infrastructure to support a fleet of EVs and analyze associated costs. Payload mass is predicted using sparse ground-truth data for all input drive cycles and an initial data analysis is conducted to assess the characteristics driving behaviors and energy consumption of the fleet using an adaptable vehicle model. Battery size requirements are determined by applying a novel charger placement algorithm to maximize routes that are viable for EVs and balance time delays with infrastructure development costs. This work details and demonstrates the different aspects of the HEVII tool, presenting preliminary results from an example use case.

ADVANCED PROPULSION SYSTEMS↗