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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 127 records · Page 7
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DOE OSTI2025

On the bulk compaction of brittle granular materials, Part III: Brittle‐to‐ductile transition and yield strength

A new and simple method is presented that enables the estimation of the yield strength (σ y ) of brittle materials (e.g., ceramics, glasses). It results from the combination of sufficiently high-stress compaction of their granular form, postmortem analysis of the crushed particles to identify the critical particle size corresponding to their brittle-to-ductile transition, and the use of a developed and simple analytical expression. Here, this method was an outcome from Part I of this three-paper series. To execute it, a granular brittle material is compacted to a sufficiently high stress, whereby the acting comminution produces both a fraction of particles having a sufficiently small size formed by ductile or plastic-like deformation and a remaining fraction of larger particles formed from brittle fracture. Postmortem microscopy is then used to identify the smallest particle size whose morphology indicates it formed from brittle fracture (d B2D ). The brittle material's σ y can then be estimated using a combination of the d B2D , Kendall's and Griffith's theories, a priori knowledge of the material's fracture toughness (K Ic ), and a fracture mechanics shape factor constant (Y) using σ y = √((32 π K Ic 2 )/(3 Y 2 d B2D )). The method's development and its use to estimate σ y for several vitreous silicates, α-quartzes, and NaCl are provided.

Compaction↗
DOE OSTI2026

Production of High Yield, Ultra‐Shallow Nitrogen‐Vacancy Centre Ensembles Through High Purity Forming gas Annealing

Dense, ultra‐shallow (<10 nm from the surface) ensembles of nitrogen‐vacancy (NV) centers in diamond are sought‐after for realising practical quantum sensing at the nanoscale. However, these ensembles typically suffer from reduced NV creation efficiency and spin coherence compared to their deeper and bulk counterparts. Consequently, most demonstrations in the literature to date have been restricted to using single NV centers with atypical coherence and charge stability properties not achievable across entire ensembles. Here, in this work, we demonstrate that controlled annealing in a high purity forming gas atmosphere improves near‐surface NV formation efficiency to over 20%. This environment preserves a high quality hydrogen termination throughout the anneal, avoiding material etching over many hours at temperatures up to 1100°C and possibly helping to suppress vacancy out‐diffusion. We show that high temperature annealing is especially vital for improving spin properties in high density, ultra‐shallow implanted samples due to the localised damage profiles produced. By allowing the formation of high yield NV ensembles with improved spin properties, the optimised forming gas anneal can facilitate the reliable production of more sensitive diamond sensors than have previously been accessible.

Healey, Alexander J. [Royal Melbourne Institute of↗
DOE OSTI2026

MoS 2 Catalysts Selectively Achieve High Yield of Liquid Oxygenate from Direct Conversion of Methane via Hydroxyl Radicals

Directly converting methane (CH 4 ) into liquid oxygenates (e.g., methanol) can circumvent the cost and engineering limits of natural gas transportation and storage. However, oxygenate yields from CH 4 remain low, and sulfur present in natural gas hinders activity in most catalysts. Here, to overcome these barriers, we employ bulk molybdenum disulfide (MoS 2 ), a low-cost, robust catalyst which selectively produces large quantities of liquid oxygenates (>900 µmol/g cat ∙hr) from methane in the presence of hydroxyl (OH • ) radicals produced from dilute hydrogen peroxide (H 2 O 2 ) at 75°C. Under realistic reaction conditions, MoS 2 partially and reversibly adopts a metastable, more electrically conductive phase (1T’) that can only be observed through in situ structural probes. Herein, we elucidate that redox synergy between H 2 O 2 and MoS 2 produces active OH • radical species that selectively transform CH 4 to surface methoxy species at the gas-solid liquid interface, leading to the unitary production of liquid oxygenate at a rate competitive with more costly precious metal catalysts, without additional catalyst preparation steps.

36 MATERIALS SCIENCE↗
DOE OSTI2025

2D Multivariate‐Metal‐Organic Frameworks (2D‐M 2 OF) for High Yield Ammonia Synthesis from Nitrate

Ammonia synthesis from nitrate offers a promising approach for both nitrate removal and nitrogen recycling. In this study, a series of 2D multivariate-metal-organic frameworks (M 2 OFs) is synthesized, incorporating transition metals such as Co, Ni, Mn, and Ag to enhance these processes. These M 2 OFs exhibit remarkable ammonia production performance, with the highest performance achieved using the quaternary structure exceeding a current density of 1 A cm −2 at −0.8 V vs RHE, with an ammonia Faradic efficiency (F.E.) of ≈90%, and a yield rate of 68 mg h −1 cm −2 . Our findings reveal that the synergy among different metal centers in M 2 OFs provides a new efficient reaction pathway for nitrate reduction via surface hydrogen co-adsorption, a mechanism not attainable with single-metal MOFs.

2D-M2OF↗
DOE OSTI2026

Dual Chemical Looping/Catalytic Process for Alkylation of Benzene With Ethane and Propane Yielding Ethylbenzene and Cumene Over Copper‐Containing Mordenite

Given the sustained demand for alkylated aromatics and the strained olefin market, there is an urgent need to develop efficient one‐step processes for the direct alkylation of aromatics using alkanes instead of olefins. Such technologies offer greater energy efficiency and sustainability by eliminating the need for separate, energy‐intensive alkane dehydrogenation steps. In this work, we report a dual chemical looping / catalytic process that couples alkane dehydrogenation with aromatic alkylation over a copper‐containing mordenite yielding up to 25% of alkylated aromatics with >97% selectivity per cycle. In situ MAS NMR and FTIR spectroscopies combined with DFT calculations showed that the alkylation of benzene with alkanes proceeds via a π‐bounded Cu(I)‐olefin intermediate, which subsequently interacts with benzene, catalyzed by Brønsted acid sites, leading to alkylated products that readily desorb from the active material into the gas phase. DFT calculations show that alkylation mediated solely by Cu(I) has prohibitively high barriers (>1.8 eV), whereas a bi‐functional pathway involving both Cu(I) and Brønsted acid sites can proceed with significantly lower barrier (0.8 eV) through a concerted C–C bond formation and proton transfer step.

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

The Staged, Pressurized Oxy-Combustion Technology: Status and Application to Boiler Retrofits to Yield Carbon-Negative Power via Biomass

Recognizing the benefits of pressurization and fuel staging on the efficiency of oxy-combustion, the staged, pressurized oxy-combustion (SPOC) process was introduced in 2012. The combination of fuel staging and pressurized oxy-combustion results in a more compact plant, a higher plant efficiency and reduced costs for pollutant and greenhouse gas removal compared with plants equipped with conventional carbon capture. This approach to power generation enables a modular boiler design and optimizes the plant for flexible operation, which is essential to meet the demands of the modern grid when it contains intermittent power sources. Originally designed to burn coal, the SPOC process is well-suited for biomass because the combustion of biomass leads to a high moisture content in the flue gas and the SPOC process is able to recover the latent heat of this moisture, enhancing system performance over that of traditional biomass combustion at atmospheric pressure. The present work is focused on evaluating the potential for utilizing the SPOC process in retrofit applications wherein the boilers of an existing plant are replaced with the SPOC process, and woody biomass is used as the fuel to yield carbon-negative power. Two applications are considered: power generation and cogeneration (heat and power). Modeling these systems in Aspen Plus demonstrates that the SPOC process surpasses the performance of baseline plants with post-combustion capture (PCC) for both power generation and cogeneration. Specifically, compared to a PCC equipped plant, the SPOC power plant has 33% higher efficiency, and the SPOC cogeneration plant reaches 42% higher net energy. Experimentally, the existing SPOC facility was fired for the first time with 100% biomass and after minor improvements were made to the feeding system, the facility demonstrated excellent performance during startup, steady-state operation and turndown.

Carbon capture and storage↗
DOE OSTI2024

Use of tritium-rich fuel to improve the yield of layered deuterium/tritium inertial fusion capsules

In deuterium–tritium (DT) ice layered implosions, nearly all hot spot mass at peak burn comes from the dense fuel. Accurate prediction of the fuel mass ablation, including the enthalpy associated with mass inflow into the hot spot from the dense fuel, is essential to understanding the energetics and ignition of the hot spot in layered implosions. A recently published boundary layer analysis (Daughton et al., 2023) indicates a faster mass ablation rate than in previous analyses of layered implosions. Inclusion of this effect provides a better match to simulations and leads to a new ignition threshold where the temperature of the dense fuel plays a critical role. This analysis motivates possible new directions for improved capsule performance. Here, the authors present evidence in support of one such approach: the use of tritium-rich ice to decrease 14 MeV neutron scattering and heating of the dense fuel, resulting in less mass ablation and more robust burn of the hot spot. It is found from numerical simulations that despite a less favorable D:T ratio in the ice, the use of a 40:60 D:T ratio leads to an increase in capsule yield of 17% percent compared with that of a 50:50 D:T ratio fuel for capsules resembling those of the recent N210808 ignition experiment on the NIF (Abu-Shawareb et al., 2022) and an increase of 74% compared with that of a 60:40 D:T ratio fuel capsule. Finally, these results are potentially important for modeling all layered implosions, since some degree of DT fractionization may arise naturally during the beta layering process. In addition, this physics is important for the feasibility of high-gain capsule designs that seek to minimize tritium usage, as in some inertial fusion energy concepts.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Utilizing machine learning to predict tensile ductility and yield strength of CoNiV-based multi-principal elements alloys

This study explores the use of machine learning (ML) as a computational tool to accelerate the design of multi-principal element alloys (MPEAs) with improved tensile elongation. An ML model was trained using available experimental data from the literature along with theoretically derived features to predict yield strength (YS) and ductility. A subset of ML-predicted compositions—CoNiVFe, CoNiVTi, CoNiVTiFe, and CoCrNiVTi—was synthesized and evaluated through tensile testing. The ML model underpredicted YS by approximately 20–30 % and overpredicted ductility by 60–70 % for Ti-containing alloys. Microstructural analysis revealed that Ti segregation at interdendritic regions contributed to early fracture, leading to discrepancies in ductility predictions. Ti segregation at these regions likely drives the increased YS due to segregation strengthening. In contrast, the CoNiVFe alloy showed good agreement with both experimental YS and elongation, with prediction errors of ∼10.2 % and ∼20.7 %, respectively. Microstructural characterization revealed minimal segregation in this alloy, suggesting that the ML model can reliably predict the properties of alloys with little to no segregation. These findings highlight the capability of ML in predicting YS with good accuracy but underscore its limitations in capturing defect-driven failure mechanisms such as segregation-induced embrittlement.

36 MATERIALS SCIENCE↗
DOE OSTI2026

Ultrafast Proton-Coupled Electron Transfer Reactions at Unit Quantum Yield

Proton-coupled electron transfer (PCET) reactions mediate essential biological energy-conversion processes, yet dynamical experiments that distinguish concerted electron/proton motion from sequential electron-transfer/proton-transfer pathways are unprecedented on ultrafast time scales. Here we report a tightly coupled donor–spacer–acceptor assembly, NDI-Sp-PhOH/BI, that enables direct interrogation of light-triggered and ultrafast PCET dynamics. Photoexcitation of the naphthalene diimide chromophore drives charge separation forming NDI radical anion and benzimidazolium phenoxy radical (PhO●/BIH+) products with a 440 fs time constant, followed by thermal charge recombination on a 5 ps time scale. Transient visible/near-infrared and mid-infrared spectroscopies independently track electron and proton motion and reveal coincident formation and decay of the charge-separated PCET products, excluding detectable phenol radical cation or phenoxide intermediates expected for sequential electron transfer-proton transfer (ET-PT) pathways. Surface-hopping quasiclassical trajectory simulations demonstrate rapid proton relocation coupled to evolution from locally excited to charge-transfer states, congruent with a concerted mechanism. These combined spectroscopic and computational results establish NDI-Sp-PhOH/BI as an archetype for ultrafast, concerted PCET occurring with unit quantum yield; further, because this platform provides distinct electronic and vibrational spectroscopic handles in its ground, electronically excited, and charge-separated states, it provides new opportunities to characterize mechanistic crossover in biomimetic PCET systems.

10 SYNTHETIC FUELS↗
DOE OSTI2026

A unifying equation for fermentation sustainability across the titer-rate-yield landscape

Industrial fermentation is central to the sustainable production of fuels and chemicals, yet commercial viability of emerging technologies hinges on improving fermentation titer, rate, and yield (TRY). How these metrics shape system cost remains difficult to generalize due to complex interactions among feedstocks, fermentation, separations, catalytic upgrading, waste management, and facility design. Here, we systematically map theoretical fermentation performance spaces (formed by all potential TRY combinations) for 32 representative biomanufacturing facilities—spanning distinct choices for feedstocks, fermentation regimes and products, separations, and catalytic upgrading—by simulating and evaluating them (via techno-economic analysis, TEA) under uncertainty (600,000 Monte Carlo simulations) and across TRY combinations (7500 TRY combinations for each of 32 configurations). Across this wide design and thermodynamic simulation space, we find the relationship between fermentation TRY and system cost is captured by a simple, generalizable mathematical equation (R 2 of 0.992 − 1.000 across our simulations; 0.954 − 1.000 when validated against prior studies that used different tools). We use this equation to elucidate key drivers that shape cost sensitivity to fermentation performance, generating widely applicable insights. By demonstrating a unifying relationship governs the impact of fermentation on biomanufacturing economics, this work establishes a foundation for agile, holistically predictive, resource-efficient strategies to prioritize fermentation research and development needs and accelerate commercialization of emerging biomanufacturing technologies.

applied mathematics↗
DOE OSTI2024

Non-covalent planarizing interactions yield highly ordered and thermotropic liquid crystalline conjugated polymers

Controlling the multi-level assembly and morphological properties of conjugated polymers through structural manipulation has contributed significantly to the advancement of organic electronics. In this work, a redox active conjugated polymer, TPT–TT, composed of alternating 1,4-(2-thienyl)-2,5-dialkoxyphenylene (TPT) and thienothiophene (TT) units is reported with non-covalent intramolecular S⋯O and S⋯H–C interactions that induce controlled main-chain planarity and solid-state order. As confirmed by density functional theory (DFT) calculations, these intramolecular interactions influence the main chain conformation, promoting backbone planarization, while still allowing dihedral rotations at higher kinetic energies (higher temperature), and give rise to temperature-dependent aggregation properties. Thermotropic liquid crystalline (LC) behavior is confirmed by cross-polarized optical microscopy (CPOM) and closely correlated with multiple thermal transitions observed by differential scanning calorimetry (DSC). This LC behavior allows us to develop and utilize a thermal annealing treatment that results in thin films with notable long-range order, as shown by grazing-incidence X-ray diffraction (GIXD). Specifically, we identified a first LC phase, ranging from 218 °C to 107 °C, as a nematic phase featuring preferential face-on π–π stacking and edge-on lamellar stacking exhibiting a large extent of disorder and broad orientation distribution. A second LC phase is observed from 107 °C to 48 °C, as a smectic A phase featuring sharp, highly ordered out-of-plane lamellar stacking features and sharp tilted backbone stacking peaks, while the structure of a third LC phase with a transition at 48 °C remains unclear, but resembles that of the solid state at ambient temperature. Furthermore, the significance of thermal annealing is evident in the ∼3-fold enhancement of the electrical conductivity of ferric tosylate-doped annealed films reaching 55 S cm −1 . More importantly, thermally annealed TPT–TT films exhibit both a narrow distribution of charge-carrier mobilities (1.4 ± 0.1) × 10 −2 cm 2 V −1 s −1 along with a remarkable device yield of 100% in an organic field-effect transistor (OFET) configuration. This molecular design approach to obtain highly ordered conjugated polymers in the solid state affords a deeper understanding of how intramolecular interactions and repeat-unit symmetry impact liquid crystallinity, solution aggregation, solution to solid-state transformation, solid-state morphology, and ultimately device applications.

Chemistry↗
DOE OSTI2025

Depolymerization of PET by common alkanolamines yields tunable monomers to expand the design space of 3D-printable, intrinsically self-healing polyamide-ionenes

Polyethylene terephthalate (PET), a ubiquitous thermoplastic used in textiles and packaging, is one of the primary contributors to plastic pollution. While PET is also one of the most recycled plastics, it has value as a rich source of chemical building blocks. When PET is depolymerized by amino alcohols (“alkanolamines”) such as monoethanolamine (MEA), terephthalamide-diol molecules are produced. In the presence of thionyl chloride (SOCl2), these diols are amenable to transformation to the corresponding dichloride monomers, which can then be polymerized via condensation methods (i.e., Menshutkin reaction) with bisimidazole compounds followed by ion-exchange to yield polyamide (PA)-ionenes with tailored structures. The PA-ionenes produced from these methods are intrinsically self-healing and possess thermal and mechanical properties which make them amenable to 3D printing. This study reports on synthetic methods and structure–property relationships in PA-ionenes that arise from the choice of molecular building blocks.

Bepari, Mousumi R. [Univ. of Alabama, Tuscaloosa, ↗
DOE OSTI2025

Ultra broadband yellow emitting lead-free metal halide perovskite like compounds with near-unity emission quantum yields

Metal halide perovskites (MHPs) are interesting semiconductor materials with potential for use in optoelectronic and photonic devices. Their practical applications are hindered due to the negative environmental effects of the lead ions (Pb 2+ ) used in these materials and stability issues. Exploring new environmentally friendly materials with lead-free metal halides and investigating the factors affecting their optical properties and stability are essential. The broadband emission and high (near-unity; ~100%) photoluminescence quantum yield (PLQY) of low-dimensional copper(I) halides make them great candidates for the next-generation luminescent materials for lighting applications. Here, a Cu(I) iodide based organic/inorganic hybrid halide (benzo-15-crown-5) 2 NaH 2 OCu 4 I 6 (BCNCI) with a zero-dimensional (0D) cluster was prepared. The BCNCI has a broadband yellow emission peaked at 548 nm with a near-unity PLQY (99.1%) upon excitation at 365 nm (ultraviolet). Upon excitation at 450 nm (blue), a high PLQY of 82% was also achieved. The luminescence mechanism was discussed in detail. Interestingly, BCNCI exhibits ultra-broad band excitation in the 300–500 nm range, which matches commercially available UV and blue-emitting chips. Compared to commercial YAG:Ce 3+ phosphors, the emission spectrum is sufficiently broad to cover the visible spectral region. This work illustrates a good example of developing an environmentally friendly white light source, using high-performance copper halides with adequate broadband excitation and emission.

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

Deciphering yield modification of hadron-triggered semi-inclusive recoil jets in heavy-ion collisions

Jet quenching is recognized as critical evidence for the existence of the quark-gluon plasma (QGP) and serves as an essential probe to study its transport properties. Measurements of hadron-triggered semi-inclusive recoil jets have gained popularity due to its capability to probe jets over an extended phase space at low transverse momenta (p T ) and large radii. Recent ALICE measurements showed that the I AA , yield ratio of recoil jets between heavy-ion and p+p collisions, rises with jet p T and exceeds unity at high p T , contradicting conventional expectations that jet quenching should result in I AA values less than one. In this contribution, we re-examine the surface bias and study the effects of energy losses for both trigger hadrons and recoil jets on I AA , employing the Linear Boltzmann Transport (LBT) model to simulate jet-medium interactions. Our findings suggest that a large portion of hadrons used for the triggers undergoes substantial energy loss, despite surface bias. In particular, the energy loss of the trigger hadrons elevates the I AA baseline, corresponding to the case of no energy loss for recoil jets, to be greatly larger than unity. This enhancement of the baseline implies that the measured I AA values being larger than unity could still signal jet quenching.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Quantifying fission yields at the National Ignition Facility using depleted uranium foil experiments

There are programs for high-Z shell experiments at the National Ignition Facility (NIF). For shells made of actinide material, a quantitative fission diagnostic is needed in order to determine how much fission took place and whether the fission was sufficient to produce a non-negligible heat source in the burning capsule. Here, we present a viable coupled experimental and theoretical technique for making quantitative fission measurements possible. The proposed scheme involves using a well-characterized set of depleted uranium foils outside an NIF capsule to verify the conversion of xenon and krypton fission fragments collected at the Radiochemical Analysis of Gaseous Samples (RAGS) facility into total fission yield. We present the calculations needed for this conversion, including the decays in and out of fission fragment chains during the RAGS pump-down of the NIF chamber.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2025

Burn propagation in magnetized high-yield inertial fusion

Recent experiments at the National Ignition Facility (NIF) have demonstrated ignition for the first time in an inertial confinement fusion (ICF) experiment, a major milestone allowing the possibility of high energy gain through burn propagation. Use of external magnetic fields, applied primarily to reduce thermal losses, could increase hotspot temperature and ease requirements for ignition, opening up the capsule design space for high energy gain. However, this same restriction of thermal transport has the potential to inhibit burn propagation, which is vital in the attainment of high gain. In this work, radiation-magnetohydrodynamics (MHD) simulations carried out using the code Chimera are used to investigate the effect of a pre-imposed magnetic field on ignition and burn propagation. This paper studies the propagation of burn using both an idealized planar model and in fully integrated 2D MHD simulations of an igniting NIF capsule. A study of magnetized burn propagation in the idealized planar model identifies three regimes of magnetized burn propagation: (1) thermal conduction driven; (2) alpha transport driven; and (3) fully suppressed burn. Simulations of NIF shot N210808 with an applied 40 T axial field show clear indication of burn suppression perpendicular to field lines, with rapid burn observed along field lines. Implosion shape is altered by the field, and anisotropic conduction causes significant modification to the rate of ablation during stagnation. These results highlight the fundamental changes to implosion dynamics in high-yield magnetized ICF and motivate further study to better optimize future magnetized target designs for high gain.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2025

Natural variation in growth and yield to waterlogging across climate-diverse pennycress accessions

Many winter annual crops, such as pennycress ( Thlaspi arvense L.), are subjected to heavy precipitation events during their growing season. Therefore, it is essential to identify pennycress accessions with natural variation in flooding resilience. We used climate modeling data to assess spring soil moisture levels in the geographic origins of 471 natural pennycress accessions. We selected 34 accessions with variation in predicted soil moisture and tested survivability under prolonged waterlogging at the rosette stage. It took seven weeks for the first accessions to die, indicating that pennycress is hardy to prolonged waterlogging at the vegetative stage. Furthermore, we chose ‘susceptible’ and ‘tolerant’ accessions to waterlog for one week at the reproductive stage, the growth stage aligned with spring rainfall. Six accessions had significantly reduced seed weight at maturity and two had minimal impacts on growth and seed yield after waterlogging and can be further explored for adaptive traits.

59 BASIC BIOLOGICAL SCIENCES↗