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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 775 records · Page 43
All sourcesNASA NTRSDOE OSTI
DOE OSTI2021

Transforming Energy through Computational Excellence. Exascale Computing: Combustion; Simulating Effects of Fuel Injection Location in Supersonic Jet Engines

Computational tractable simulations using an adaptive-mesh-refinement solverfor compressible reacting flows help researchers understand how variations in fuel injection location within the supersonic flow cavity impacts combustion efficiency. By identifying the important physical determinants of the combustion processes, this study shows a promising pathway to improving flame stability and combustion efficiency, as well as reducing emissions.

adaptive mesh refinement↗
DOE OSTI2021

Ethanol as a Liquid Organic Hydrogen Carrier for Seasonal Microgrid Application: Catalysis, Theory, and Engineering Feasibility

Here, we describe the benefits and challenges of a green approach to seasonal energy storage using ethanol as a liquid organic hydrogen carrier (LOHC). We evaluate the cycling efficiency of hydrogen release from ethanol (EtOH) to form ethyl acetate (EtOAc) as the spent LOHC and the subsequent regeneration of EtOH from EtOAc catalyzed by a single molecular catalyst, Ru-MACHO, at a moderate pressure of H 2 , mild reaction temperature, and high selectivity. From experimental and computational studies, we were able to minimize catalyst deactivation, regenerate the active catalyst post reactions, and establish the energy profile of the deactivation pathway relative to the on-cycle pathway catalyzed by Ru-MACHO. Based upon these findings, we performed a reactor design analysis to determine the footprint of an EtOH-based storage system to provide 85 MWh of energy by storing 5 metric tons (MT) of H 2 . We conclude that the heating and cooling required to maintain H 2 partial pressure present a significant engineering challenge for widespread deployment of this system.

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

Understanding Fracture Aperture and Permeability Evolution due to Carbonate Mineralization Utilizing 3D Printing

Caprock formations are a crucial part of subsurface-engineered systems. Composed largely of shale, caprocks act as natural barriers that prevent the upward migration of fluids, thereby ensuring the containment of stored substances in subsurface formations. Fractures in these formations are potential leakage pathways for stored fluids. Mineral precipitation reactions in these fractures, particularly calcite, can significantly restrict the fluid permeability, reducing leakage potential. However, predictive capabilities of mineral precipitation in fractures and associated permeability evolution are limited due to a lack of fundamental understanding of such reactions in natural samples, complicated by mineral heterogeneity and the complexity of the fracture structure. In this study, 3D-printed fracture samples are used to understand the impact of carbonate mineralization on fracture aperture and permeability evolution. Samples were printed using a digital light processing (DLP) 3D printer and commercial liquid resin. Calcite precipitation was first tested on printed 2D films before conducting plug flow column experiments aimed to understand fracture permeability changes due to mineral precipitation. Contact angle measurement and Fourier transform infrared (FTIR) spectroscopy on printed 2D films show evidence of a substantial amount of surface energy for calcite nucleation and precipitation. Surface topography analysis of printed fractured surfaces reveals comparable values, highlighting the high replicability of the printed samples. During the column experiments, the permeability reduces exponentially due to a decrease in fracture aperture. Reductions in fracture aperture estimated from effluent concentration and 3D X-ray computed tomography (CT) show comparable results. Moreover, 3D X-ray CT images suggest the impact of local flow velocities on precipitation. The insights gained from this research contribute to a deeper understanding of the permeability evolution due to carbonate mineralization in caprock formations.

3D printing↗
DOE OSTI2023

Realizing high-capacity all-solid-state lithium-sulfur batteries using a low-density inorganic solid-state electrolyte

Abstract Lithium-sulfur all-solid-state batteries using inorganic solid-state electrolytes are considered promising electrochemical energy storage technologies. However, developing positive electrodes with high sulfur content, adequate sulfur utilization, and high mass loading is challenging. Here, to address these concerns, we propose using a liquid-phase-synthesized Li 3 PS 4 -2LiBH 4 glass-ceramic solid electrolyte with a low density (1.491 g cm −3 ), small primary particle size (~500 nm) and bulk ionic conductivity of 6.0 mS cm −1 at 25 °C for fabricating lithium-sulfur all-solid-state batteries. When tested in a Swagelok cell configuration with a Li-In negative electrode and a 60 wt% S positive electrode applying an average stack pressure of ~55 MPa, the all-solid-state battery delivered a high discharge capacity of about 1144.6 mAh g −1 at 167.5 mA g −1 and 60 °C. We further demonstrate that the use of the low-density solid electrolyte increases the electrolyte volume ratio in the cathode, reduces inactive bulky sulfur, and improves the content uniformity of the sulfur-based positive electrode, thus providing sufficient ion conduction pathways for battery performance improvement.

25 ENERGY STORAGE↗
DOE OSTI2025

Data for "Decompartmentalization of the yeast mitochondrial metabolism to improve chemical production in Issatchenkia orientalis "

Microbial production of chemicals may suffer from inadequate cofactor provision, a challenge further exacerbated in yeasts due to compartmentalized cofactor metabolism. Here, we perform cofactor engineering through the decompartmentalization of mitochondrial metabolism to improve succinic acid (SA) production in Issatchenkia orientalis . We localize the reducing equivalents of mitochondrial NADH to the cytosol through cytosolic expression of its pyruvate dehydrogenase (PDH) complex and couple a reductive tricarboxylic acid pathway with a glyoxylate shunt, partially bypassing an NADH-dependent malate dehydrogenase to conserve NADH. Cytosolic SA production reaches a titer of 104 g/L and a yield of 0.85 g/g glucose, surpassing the yield of 0.66 g/g glucose constrained by cytosolic NADH availability. Additionally, expressing cytosolic PDH, we expand our I. orientalis platform to enhance acetyl-CoA-derived citramalic acid and triacetic acid lactone production by 1.22- and 4.35-fold, respectively. Our work establishes I. orientalis as a versatile platform to produce markedly reduced and acetyl-CoA-derived chemicals.

bioproducts↗
DOE OSTI2023

Modeling and Simulation Development Pathways to Accelerating KP-FHR Licensing (Final Report)

This project assembles a strong U.S. industry and national laboratory team to complete scope of work. Kairos Power (KP), headquartered in Alameda, CA, is the leader of this effort and has built an internal team of highly competent engineers and managers with extensive combined experience in nuclear power, conventional power, product development, and licensing. INL, ANL, and LANL bring unique capabilities in advanced reactor R&D and licensing. The project funding source is the result of FOA No. 0001817, U. S. Industry Opportunities for Advanced Nuclear Technology Development. There has been on-going work and this Access Cooperative Research and Development Agreement (CRADA) will cover the remaining work scope of FOA 0001817. KP is implementing innovative strategies that can reduce the cost and accelerate the initial demonstration of the Kairos Power Fluoride-salt-cooled, High-temperature Reactor (KP-FHR) to meet the needs of the U.S. electricity market by 2030. Licensing of the KP-FHR could be significantly accelerated using advanced computing methods with sufficient predictive capabilities to be able to extrapolate potential response of the structure in different scenarios. However, currently used computational methods heavily rely on empirical fits and cannot be used for extrapolation. The scope focuses on improving the modeling capability in the NEAMS Grizzly structural mechanics code and the NEAMS BISON fuel performance code and the NEAMS SAM systems analysis code. This work leverages the expertise and know-how gathered in three DOE National Laboratories – INL, ANL, and LANL.

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS↗
DOE OSTI2022

Robust silane self-assembled monolayer coatings on plasma-engineered copper surfaces promoting dropwise condensation

Dropwise condensation is well known to result in better heat transfer performance owing to efficient condensate/droplet removal, which can be harnessed in various industrial heat/mass transfer applications such as power generation and conversion, water harvesting/desalination, and electronics thermal management. The key to enhancing condensation via the dropwise mode is thin low surface energy coatings (<100 nm) with low contact angle hysteresis. Ultrathin (<5 nm) silane self-assembled monolayers (or SAMs) have been widely studied to promote dropwise condensation due to their minimal thermal resistance and scalable integration processes. Such thin coatings typically degrade within an hour during condensation of water vapor. After coating failure, water vapor condensation transitions to the inefficient filmwise mode with poor heat transfer performance. We enhance silane SAM quality and durability during water vapor condensation on copper compared to state-of-the-art silane coatings on metal surfaces. We achieve this via (i) surface polishing to sub-10 nm levels, (ii) pure oxygen plasma surface treatment, and (iii) silane coating integration with the copper substrate in an anhydrous/moisture-free environment. The resulting silane SAM has low contact angle hysteresis (≈20°) and promotes efficient dropwise condensation of water for >360 hours without any visible sign of coating failure/degradation in the absence of non-condensable gases. We further demonstrate enhanced heat transfer performance (≈5-7× increase over filmwise condensation) over an extended period of time. Surface characterization data post-condensation leads us to propose that in the absence of non-condensable gases in the vapor environment, the silane SAM degrades due to reduction and subsequent dissolution of copper oxide at the oligomer-substrate interface. The experiments also indicate that the magnitude of surface subcooling (or condensation rate) affects the rate of coating degradation. Finally, this work identifies a pathway to durable dropwise promoter coatings that will enable efficient heat transfer in industrial applications.

42 ENGINEERING↗
DOE OSTI2022

Advancing biological processing for valorization of plastic wastes

We report the useful applications of plastics are as significant as the problems associated with their disposal. Current waste management strategies are ineffective at preventing the flow of plastics into landfills, wastewater treatment, and the environment. Despite the importance of recycling technologies, most plastics are used for consumables and are discarded after limited usage. Moreover, only certain plastics are recycled, and those that are generally yield lower value products. Discovering alternative routes for valorizing plastic wastes is essential. Emerging research involves the use of biocatalysts (i.e., enzymes and microorganisms) to produce valuable products like specialty polymers, biosurfactants, and drug precursors from these feedstocks. These bioprocesses commonly integrate physio-chemical pretreatments (to generate biologically reactive intermediates) and biological upgrading (to convert intermediates to products). Herein, publications that explore plastic deconstruction technologies and bioprocesses are reviewed with an emphasis on plastic waste valorization. Understanding how microorganisms metabolize the intermediates of plastic degradation and manage their inhibitory effects is a prerequisite for engineering bioprocesses. For these heterogeneous wastes, a paradigm shift from axenic cultivation of microorganisms to cultivation of microbial consortia may benefit conversion efficiency and stress resilience. Thus, a summary is provided for metabolic pathways and constituent enzymes required to synthesize biofuels, biomaterials, and chemicals from biologically reactive intermediates. Colossal challenges associated with the use of plastics as feedstocks for direct biological processing highlight the need for integrating physical, chemical, and biological technologies.

59 BASIC BIOLOGICAL SCIENCES↗
DOE OSTI2025

Electron Sextets as Optically Addressable Molecular Qubits: Triplet Carbenes

There is a growing demand in quantum information science and sensing for electron spin purification and readout via a spin-optical interface. This technique, known as optically detected magnetic resonance (ODMR), has been applied to diamond-NV centers and transition-metal complexes. Metal-free counterparts of these optically addressable spin qubits promise to be cheaper, more sustainable color centers with prolonged polarization lifetimes. However, progress has been hindered by the low ODMR signals of carbon-based π-diradicals, partly due to the lack of a ground singlet-to-triplet intersystem crossing (ISC). In this work, we propose exploring organic systems that are even more electron-deficient: electron sextets. Using triplet carbenes as an example, we illustrate how the ground singlet-triplet gap can be widened beyond thermal energy with the associated singlet-to-triplet ISC made available by vibronic effects. Through careful molecular engineering, this ISC can occur at a rate similar to and with an opposite spin selectivity from the excited-state ISC well-established in π-diradicals, unlocking a new ODMR pathway with potential signal gains. Persistent triplet carbenes are a renascent field, with multiple stable molecules being isolated in the past five years. To motivate further development of its emissive properties, we illustrate our design in three realistic carbene candidates that incorporate existing strategies for carbene stabilization. Furthermore, we believe that a new realm of quantum materials can be uncovered by expanding our scope toward stable electron sextets.

Carbene compounds↗
DOE OSTI2026

Unlocking superplasticity in medium and high-entropy alloys

Superplasticity, the capacity of materials to sustain extraordinary tensile elongations at elevated temperatures, underpins a range of advanced metal-forming technologies. Conventionally, it is achieved in fine-grained alloys where deformation is dominated by grain-boundary sliding, accommodated by diffusion and dislocation activity. The advent of medium- and high-entropy alloys (M/HEAs), with their high chemical complexity and unconventional phase stability, offers new pathways to superplastic behavior beyond traditional alloy systems. Although investigated only recently, several M/HEAs already exhibit elongations that rival or exceed those of classical superplastic materials, particularly when ultrafine or metastable microstructures are engineered. Here, we review progress in understanding superplastic deformation in M/HEAs, emphasizing the interplay among composition, initial microstructure, thermomechanical processing, and microstructural evolution during high-temperature deformation. We discuss approaches to generating the fine-grained structures necessary for grain-boundary sliding, including severe plastic deformation and tailored heat treatments. We further highlight dynamic phenomena such as phase transformations, evolving grain-boundary chemistry, and deformation-induced grain refinement that can enhance plasticity in these systems. These mechanisms often shift the balance of deformation processes, enabling large elongations even outside classical criteria. Finally, we outline key challenges for application, including cost, scalability, recyclability, and microstructural stability.

klenam, Desmond [University of the Witwatersrand, ↗
DOE OSTI2022

Achieving complete electrooxidation of ethanol by single atomic Rh decoration of Pt nanocubes

Significance Direct ethanol fuel cells are attracting growing attention as portable power sources due to their advantages such as higher mass-energy density than hydrogen and less toxicity than methanol. However, it is challenging to achieve the complete electrooxidation to generate 12 electrons per ethanol, resulting in a low fuel utilization efficiency. This manuscript reports the complete ethanol electrooxidation by engineering efficient catalysts via single-atom modification. The combined electrochemical measurements, in situ characterization, and density functional theory calculations unravel synergistic effects of single Rh atoms and Pt nanocubes and identify reaction pathways leading to the selective C–C bond cleavage to oxidize ethanol to CO 2 . This study provides a unique single-atom approach to tune the activity and selectivity toward complicated electrocatalytic reactions.

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

A New Generation of Innovation

This presentation discussed how the consortium approach can help advance all early-stage water splitting technologies and enable a new generation of innovation. Presented during the Advanced Pathways Breakout Panel Session at the DOE Hydrogen Shot Summit, September 1, 2021.

advanced water splitting materials↗
DOE OSTI2021

Cryo-EM structures of engineered active bc 1- cbb 3 type CIII 2 CIV super-complexes and electronic communication between the complexes

Respiratory electron transport complexes are organized as individual entities or combined as large supercomplexes (SC). Gram-negative bacteria deploy a mitochondrial-like cytochrome (cyt) bc 1 (Complex III, CIII 2 ), and may have specific cbb 3 -type cyt c oxidases (Complex IV, CIV) instead of the canonical aa 3 -type CIV. Electron transfer between these complexes is mediated by soluble ( c 2 ) and membrane-anchored ( c y ) cyts. Here, we report the structure of an engineered bc 1 - cbb 3 type SC (CIII 2 CIV, 5.2Å resolution) and three conformers of native CIII 2 (3.3 Å resolution). The SC is active in vivo and in vitro, contains all catalytic subunits and cofactors, and two extra transmembrane helices attributed to cyt c y and the assembly factor CcoH. The cyt c y is integral to SC, its cyt domain is mobile and it conveys electrons to CIV differently than cyt c 2 . The successful production of a native-like functional SC and determination of its structure illustrate the characteristics of membrane-confined and membrane-external respiratory electron transport pathways in Gram-negative bacteria.

42 ENGINEERING↗
DOE OSTI2021

Chapter 4: What We Can Learn from Measuring Metabolic Fluxes in Cyanobacteria

Cyanobacteria with the capability of oxygen-evolving photosynthesis play a vital role in the global carbon, oxygen, and nitrogen cycles. From a biochemical perspective, all phenotypic traits and functions of cyanobacteria are derived from the potential of their metabolism and mirrored in metabolic fluxes through an integrated metabolic network. Metabolic flux, the rate of turnover of molecules through a metabolic pathway, is therefore of great importance for an in-depth understanding of the role of cyanobacteria in the biosphere. Recent interest in cyanobacteria metabolic fluxes is also motivated by the prospect to utilize their light-driven CO2 fixation for sustainable production of valuable chemicals and biofuels. Valorization of cyanobacterial metabolism will require engineering of the native metabolic network - a challenge that can benefit from a quantitative understanding of metabolic reactions taking place intracellularly. In this chapter, we will discuss some intriguing questions relevant to metabolic fluxes in cyanobacteria: How are metabolic fluxes predicted or measured? What do we know about the fluxome inside various cyanobacteria thus far? How are they different between strains as well as in different conditions? And how can we use fluxomics information to guide metabolic engineering and synthetic biology? This chapter will highlight updated knowledge on cyanobacterial metabolism. Specifically, we will focus on providing readers a quantitative vision to understand how this photosynthetic model works.

BASIC BIOLOGICAL SCIENCES,INORGANIC, ORGANIC, PHYS↗
DOE OSTI2022

For the Public Good: Connecting, Retaining, and Recognizing Current and Future RSEs at U.S. National Research Laboratories and Agencies

U.S. national research laboratories and agencies play an integral role in advancing science and technology for the public good. The authors of this article, as research software engineers (RSEs) and allies from eight unique national R&D organizations, came together to explore RSE needs from the perspective of national institutions. We identified three key areas of improvement for future RSEs to pursue science in the national interest: community establishment, hiring and retention, and recognition. In conclusion, to retain and cultivate this essential talent, U.S. national institutions must evolve to support appropriate career pathways for RSEs, and to recognize and reward RSEs’ work.

42 ENGINEERING↗
DOE OSTI2025

A small number of point mutations confer formate tolerance in Shewanella oneidensis

ABSTRACT Microbial electrosynthesis (MES) is a sustainable approach to chemical production from CO 2 and clean electricity. However, limitations in electron transfer efficiency and gaps in understanding of electron transfer pathways in MES systems prevent full realization of this technology. Shewanella oneidensis could serve as an MES biocatalyst because it has a well-studied, efficient transmembrane electron transfer pathway. A key first step in MES in this organism could be CO 2 reduction to formate. However, we report that wild-type S. oneidensis does not tolerate high levels of formate. In this work, we created and characterized formate-tolerant strains of S. oneidensis for further engineering and future use in MES systems through adaptive laboratory evolution. Two different point mutations in a gene encoding a predicted sodium-dependent bicarbonate transporter and a DUF2721-containing protein separately confer formate tolerance to S. oneidensis . The mutations were further evaluated to understand their role in improving formate tolerance. We also show that the wild-type and mutant versions of the putative sodium-dependent bicarbonate transporter improve formate tolerance of Zymomonas mobilis , indicating the potential of transferring this formate tolerance phenotype to other organisms. IMPORTANCE Shewanella oneidensis is a bacterium with a well-studied, efficient extracellular electron transfer pathway. This capability could make this organism a suitable host for microbial electrosynthesis using CO 2 or formate as feedstocks. However, we report here that formate is toxic to S. oneidensis , limiting the potential for its use in these systems. In this work, we evolve several strains of S. oneidensis that have improved formate tolerance, and we investigate some mutations that confer this phenotype. The phenotype is confirmed to be attributed to several single point mutations by transferring the wild-type and mutant versions of each gene to the wild-type strain. Finally, the formate tolerance mechanism of one variant is studied using structural modeling and expression in another host. This study, therefore, presents a simple method for conferring formate tolerance to bacterial hosts.

Cross, Megan C. Gruenberg (ORCID:0000000291589900)↗