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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

Machine Learned Force Field Modeling of Metal Organic Frameworks for CO2 Direct Air Capture

Metal organic frameworks (MOFs) are a large class of porous materials and have garnered significant interest due to their large surface areas and their tunable physical and chemical properties. Numerous prior studies have been performed to screen large databases of this material class for promising DAC sorbent materials. These studies have often relied on classical model potentials. While density functional theory (DFT) calculations have been shown to be very accurate for modeling the interaction of CO2 with MOFs, such calculations are too computationally demanding for statistically significant adsorption predictions. To overcome this barrier, we developed methods for training models to achieve DFT-level accuracy for the forces and energies associated with MOF flexibility and CO2 adsorption using machine learned force fields (MLFFs). These methods were parametrized based on DFT calculations of CO2 in a flexible MOF and used to predict MOF structural properties as well as CO2 adsorption in several MOFs.

Findley, John↗
DOE OSTI2025

Building partnerships for development of sustainable energy systems with atmospheric measurements

Atmospheric dynamics often play a critical role in the sustainability and reliability of diverse forms of energy production. This is especially true for the growing number of renewable energy deployments that harness aspects of the environment for power production. While the University of Memphis has a strong research background in energy systems, we have little experience working with the Earth and Environmental Systems Science Division (EESSD) and their associated User Facilities. Of particular interest to us is the Atmospheric Science Research and the Atmospheric Radiation Measurement (ARM) user facility to address surface-boundary layer interactions and physical phenomena. One of the major challenges for understanding and developing energy systems and management platforms is accurate modeling/forecasting of atmospheric conditions across disparate spatial and temporal scales. These conditions are often required to understand the lowest levels of the atmospheric boundary layer, but are also important to understand higher atmospheric conditions where aerosols affect cloud development. The objective of this work was to develop partnerships with national laboratories for collaboration on environmental science and its intersection with sustainable energy systems, as well as to leverage the ARM user facility data repositories to enhance our research capabilities in energy systems and their inter-dependence on environmental systems for future engagement with EESSD. Specifically, we accomplished these objectives by (1) developing collaborations with Oakridge National Laboratory ARM Data Science and Integration Group which resulted in student internships, (2) employed ARM data to develope modeling of the atmospheric boundary layer optical turbulence, and (3) optimally-sized large-scale renewable energy systems and their associated energy storage systems with ARM repository data.

29 ENERGY PLANNING, POLICY, AND ECONOMY↗
DOE OSTI2016

Effects of liquid subcooling and initial rod temperature on the minimum film boiling temperature

This paper presents an experimental study on the minimum film boiling temperature (T{sub min}) and its sensitivity to liquid subcooling and initial rod temperature. T{sub min} is measured through a quenching experiment using a vertical stainless steel rod that is quenched in a distilled water bath. The cylindrical stainless steel rod has a flat circular end with diameter of 9.5 mm similar to that of a fuel rod and length of 25 cm. Physically, T{sub min} is used to define the boundary between film boiling and transition boiling, beyond which temperature liquid would not be able to come into physical contact with the solid surface. Results show that the quenching curves are affected by varying the liquid subcooling but are not significantly altered by the initial rod temperature. Additionally, the experiments include visualization of the boiling regimes. The visualization gives insight into the film flow behavior that is found to depend strongly on the liquid subcooling. It also provides an understanding of the phenomenon for quench front axial propagation (authors)

22 GENERAL STUDIES OF NUCLEAR REACTORS↗
DOE OSTI2016

Development of SiC-based Cladding for Accident Tolerant Fuels

Fuels and core structures in current light water reactors (LWR's) are vulnerable to catastrophic failure in severe accidents. This vulnerability is attributed primarily to the rapid oxidation kinetics of zirconium alloys in a water vapor environment at very high temperatures. Alternative materials to zirconium alloys with reduced oxidation kinetics are sought to enable enhanced accident-tolerant fuels and cores. Among the candidate alternatives, silicon carbide (SiC) - based materials, in particular continuous SiC fiber-reinforced SiC matrix ceramic composites (SiC/SiC composites), are considered to offer outstanding safety benefits. The primary objective of this work is to provide with updated overviews of the concepts, development status, and future prospect for the SiC-based accident-tolerant fuel (ATF) claddings. A systematic technology evaluation program plan was developed and updated to review the technologies needed, to identify and analyze critical gaps, and to lay out a road-map toward establishing key technologies. The technology review and the gap analysis in this exercise were based on an early study and community workshops. Many of the technical gaps identified are related with the three key feasibility issues: hydrothermal corrosion, mechanical failure, and fuel compatibility. Additional performance issues including accident-tolerance features and fission product retention during the normal operation have also been identified. The program plan was designed to systematically address the key gap issues and is formulated in a work breakdown structure. Simultaneously, the plan is being established to set a technical program for advancing the technological readiness levels of concept non-specific essential technologies in three top-level categories of Design and Failure, Environmental Effects, and Off-normal Behavior. The execution of the program plan is in progress across the U.S. Department of Energy laboratories, industries, universities, and international collaborators. The critical issues for SiC composite-based fuel cladding concepts were found to be related to the performance in the normal operation. In particular, radiation-assisted hydrothermal corrosion and the gaseous fission product (FP) retention are identified to be the most critical issues. The primary ORNL concept pursues the use of dual-purpose coating on the SiC composite cladding wall to mitigate the corrosion and the gas permeation issues at the same time, whereas the alternative approaches such as the dense monolithic SiC protective layer combined with the water chemistry control may be feasible. Surface metallization through variations of physical vapor deposition and electroplating are being demonstrated. The FP gas retention is an issue associated with the cracking for the ceramic matrix composite cladding. To establish the probabilistic failure behavior, the relevant test methods were developed in ASTM Committee C28 on Advanced Ceramics. Toward the end-plugging technology development, various methods for joining SiC to SiC had been developed and tested for mechanical properties, irradiation effects, and environmental effects. Multiple methods including the pressureless transient eutectic SiC joining and CVD-based SiC joining were identified particularly promising. In addition, a multi-physics, three-dimensional finite element-based modeling is in progress toward an integrated simulation of the SiC composite-cladded fuel evolutions. (authors)

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2025

Data Centers and Digital Assurance Workshop 2 – Prioritizing Digital Assurance Challenges, Session 2

The second session of the TADA (Technical Assistance for Digital Assurance) Data Centers Cohort, held on November 10, 2025, focused on prioritizing digital assurance challenges at the intersection of data centers and the electric grid. Building on the foundational concepts introduced in Workshop 1, this session deepened the application of the Threat–Vulnerability–Consequence (TVC) framework and emphasized the urgency of addressing cybersecurity, supply chain integrity, and operational reliability. Participants explored the growing convergence of digital and physical systems, the expanding attack surface due to global supply chain dependencies, and the implications of AI-driven load behavior. Real-world incidents—including the Volt Typhoon campaign and vulnerabilities in Solarman and Deye platforms—were analyzed to illustrate the risks of unpatched systems, insecure APIs, and inadequate vendor oversight. Key themes included architecture and interface weaknesses, governance gaps, and human and procedural shortcomings. The workshop also examined the evolving regulatory landscape, highlighting new federal mandates around Foreign Entity of Concern (FEOC) compliance and large-load reliability standards. Through interactive exercises, stakeholders ranked and mapped digital assurance risks from their respective perspectives—utilities, operators, and vendors—laying the groundwork for mitigation strategies and shared accountability models to be developed in Workshop 3. Session 2 of 3.

24 - POWER TRANSMISSION AND DISTRIBUTION↗
DOE OSTI2014

Cholesterol enhances surface water diffusion of phospholipid bilayers

Elucidating the physical effect of cholesterol (Chol) on biological membranes is necessary towards rationalizing their structural and functional role in cell membranes. One of the debated questions is the role of hydration water in Chol-embedding lipid membranes, for which only little direct experimental data are available. Here, we study the hydration dynamics in a series of Chol-rich and depleted bilayer systems using an approach termed {sup 1}H Overhauser dynamic nuclear polarization (ODNP) NMR relaxometry that enables the sensitive and selective determination of water diffusion within 5–10 Å of a nitroxide-based spin label, positioned off the surface of the polar headgroups or within the nonpolar core of lipid membranes. The Chol-rich membrane systems were prepared from mixtures of Chol, dipalmitoyl phosphatidylcholine and/or dioctadecyl phosphatidylcholine lipid that are known to form liquid-ordered, raft-like, domains. Our data reveal that the translational diffusion of local water on the surface and within the hydrocarbon volume of the bilayer is significantly altered, but in opposite directions: accelerated on the membrane surface and dramatically slowed in the bilayer interior with increasing Chol content. Electron paramagnetic resonance (EPR) lineshape analysis shows looser packing of lipid headgroups and concurrently tighter packing in the bilayer core with increasing Chol content, with the effects peaking at lipid compositions reported to form lipid rafts. The complementary capability of ODNP and EPR to site-specifically probe the hydration dynamics and lipid ordering in lipid membrane systems extends the current understanding of how Chol may regulate biological processes. One possible role of Chol is the facilitation of interactions between biological constituents and the lipid membrane through the weakening or disruption of strong hydrogen-bond networks of the surface hydration layers that otherwise exert stronger repulsive forces, as reflected in faster surface water diffusivity. Another is the concurrent tightening of lipid packing that reduces passive, possibly unwanted, diffusion of ions and water across the bilayer.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2019

Electrochemical-Reaction-Driven Interfacial Stress in a Solid-Solid Layered Architecture

Reaction-driven interfacial growth causes significant strain in layered architectures accompanied by mass transfer and moving boundaries. We present an analytical construct of the stress generated in a multilayer film, which incorporates the elastic-plastic strain of the growth layer, which suggests its strong dependence on the mechanical properties and thickness. This analytical formalism is further applied to a layered all-solid-state lithium battery architecture. This study demonstrates that mechanical stability can be enhanced by using a positive electrode material with high stiffness, porous hosts for lithium plating, and small external elastic constraints to buffer the volumetric changes in the electrode material. Furthermore, our results also reveal that small surface flaws in the solid electrolyte and high internal hydrostatic pressure can alleviate lithium dendrite growth through surface cracks.

25 ENERGY STORAGE↗
DOE OSTI2021

Quantifying the Impacts of Land Surface Modeling on Hub-Height Wind Speed under Different Soil Conditions

We investigate the impact of three land surface models (LSMs) on hub-height wind speed under three different soil regimes (dry, wet, and frozen) to understand and improve the physics of wind energy forecasts using the Weather Research and Forecasting (WRF) model. A six-day representative period is selected for each soil condition. The simulated wind speed, surface energy budget and soil properties are compared with the observations collected from the second Wind Forecast Improvement Project (WFIP2). For the selected cases, our simulation results suggest that, the impact of LSMs on hub-height wind speed are sensitive to the soil states but not so much to the choice of LSM. The simulated hub-height wind speed is in much better agreement with the observations for the dry soil case than the wet and frozen soil cases. Over the dry soil, there is a strong physical connection between the land surface and hub-height wind speed through near-surface turbulent mixing. Over the wet soil, the simulated hub-height wind speed is less impacted by land surface due to weaker surface fluxes and more dominated by large-scale synoptic disturbances. Over the frozen soil, the land surface model seems to have limited impact on hub-height wind speed variability due to the decoupling of the land surface with the overlying atmosphere. Two main sources of modeling uncertainties are proposed. The first are the insufficient model physics representing the surface energy budget, especially the ground heat flux, and the second are the inaccurate initial soil states such as soil temperature and soil moisture.

Xia, Geng↗
DOE OSTI2018

Identifying microturbulence regimes in a TCV discharge making use of physical constraints on particle and heat fluxes

Reducing the uncertainty on physical input parameters derived from experimental measurements is essential towards improving the reliability of gyrokinetic turbulence simulations. This can be achieved by introducing physical constraints. Amongst them, the zero particle flux condition is considered here. A first attempt is also made to match as well the experimental ion/electron heat flux ratio. This procedure is applied to the analysis of a particular Tokamak à Configuration Variable discharge. A detailed reconstruction of the zero particle flux hyper-surface in the multi-dimensional physical parameter space at fixed time of the discharge is presented, including the effect of carbon as the main impurity. Both collisionless and collisional regimes are considered. Hyper-surface points within the experimental error bars are found. In conclusion, the analysis is done performing gyrokinetic simulations with the local version of the GENE code, computing the fluxes with a Quasi-Linear (QL) model and validating the QL results with non-linear simulations in a subset of cases.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2016

Low Cost, High Capacity Regenerable Sorbent for Carbon Dioxide Capture from Existing Coal-fired Power Plants

In this project TDA Research, Inc (TDA) has developed a new post combustion carbon capture technology based on a vacuum swing adsorption system that uses a steam purge and demonstrated its technical feasibility and economic viability in laboratory-scale tests and tests in actual coal derived flue gas. TDA uses an advanced physical adsorbent to selectively remove CO 2 from the flue gas. The sorbent exhibits a much higher affinity for CO 2 than N 2 , H 2 O or O 2 , enabling effective CO 2 separation from the flue gas. We also carried out a detailed process design and analysis of the new system as part of both sub-critical and super-critical pulverized coal fired power plants. The new technology uses a low cost, high capacity adsorbent that selectively removes CO 2 in the presence of moisture at the flue gas temperature without a need for significant cooling of the flue gas or moisture removal. The sorbent is based on a TDA proprietary mesoporous carbon that consists of surface functionalized groups that remove CO 2 via physical adsorption. The high surface area and favorable porosity of the sorbent also provides a unique platform to introduce additional functionality, such as active groups to remove trace metals (e.g., Hg, As). In collaboration with the Advanced Power and Energy Program of the University of California, Irvine (UCI), TDA developed system simulation models using Aspen PlusTM simulation software to assess the economic viability of TDA’s VSA-based post-combustion carbon capture technology. The levelized cost of electricity including the TS&M costs for CO 2 is calculated as $116.71/MWh and $113.76/MWh for TDA system integrated with sub-critical and super-critical pulverized coal fired power plants; much lower than the $153.03/MWhand $147.44/MWh calculated for the corresponding amine based systems. The cost of CO 2 captured for TDA’s VSA based system is $38.90 and $39.71 per tonne compared to $65.46 and $66.56 per tonne for amine based system on 2011 $ basis, providing 40% lower cost of CO 2 captured. In this analysis we have used a sorbent life of 4 years. If a longer sorbent life can be maintained (which is not unreasonable for fixed bed commercial PSA systems), this would lower the cost of CO 2 captured by $0.05 per tonne (e.g., to $38.85 and $39.66 per tonne at 5 years sorbent replacement). These system analysis results suggest that TDA’s VSA-based post-combustion capture technology can substantially improve the power plant’s thermal performance while achieving near zero emissions, including greater than 90% carbon capture. The higher net plant efficiency and lower capital and operating costs results in a substantial reduction in the cost of carbon capture and cost of electricity for the power plant equipped with TDA’s technology.

20 FOSSIL-FUELED POWER PLANTS↗
DOE OSTI2021

Characterizing the plasma-induced thermal loads on a 200 kW light-ion helicon plasma source via infra-red thermography

The light-ion helicon plasma source of the Proto-MPEX linear plasma device has been recently upgraded to enable pulsed (0.5–1 s) operation up to 200 kW. The main objective of this work is to report on the plasma-induced surface heat fluxes incident on the helicon window during high power operation (60–150 kW net power) for the purpose of the design of the upcoming material plasma exposure eXperiment (MPEX). The IR imaging system and associated physics models for the extraction of surface heat fluxes are presented. Furthermore, experimental results demonstrate that the control of the plasma strike point via magnetic flux mapping and the use of dedicated limiters is effective at reducing the heat loads on the dielectric window. Moreover, it is found that the flux mapping must create a gap between the plasma and the dielectric window of at least the plasma radial decay length. Extrapolated to 200 kW net RF power, this mode of operation can reduce the power lost to the dielectric window by 33%. The results presented have direct application to the design of high-powered helicon plasma sources that operate in a steady state. Examples include linear divertor simulators such as MPEX, electric thrusters, negative ion sources for NBI and linear plasma–material interaction test stands.

70 PLASMA PHYSICS AND FUSION TECHNOLOGY↗
DOE OSTI2019

The Techniques of Surface Alignment of Liquid Crystals

Alignment of liquid crystal (LC) molecules is an important topic of physics of anisotropic fluids. Here, the boundary conditions and the surface properties of the material in contact with an LC dictate the preferred orientation of the molecules at the interface.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2023

Molecular Dynamics Investigation of Nanoscale Hydrophobicity of Polymer Surfaces: What Makes Water Wet?

The wettability of a polymer surface–related to its hydrophobicity or tendency to repel water–can be crucial for determining its utility, such as for a coating or a purification membrane. While wettability is commonly associated with the macroscopic measurement of a contact angle between surface, water, and air, the molecular physics that underlie these macroscopic observations are not fully known, and anticipating relative behavior of different polymers is challenging. To address this gap in molecular-level understanding, we use molecular dynamics simulations to investigate and contrast interactions of water with six chemically distinct polymers: polytetrafluoroethylene, polyethylene, polyvinyl chloride, poly(methyl methacrylate), Nylon 66, and polyvinyl alcohol. We show that several prospective quantitative metrics for hydrophobicity agree well with experimental contact angles. Moreover, the behavior of water in proximity to these polymer surfaces can be distinguished with analysis of interfacial water dynamics, extent of hydrogen bonding, and molecular orientation–even when macroscopic measures of hydrophobicity are similar. The predominant factor dictating wettability is found to be the extent of hydrogen bonding between polymer and water, but the precise manifestation of hydrogen bonding and its impact on surface-water structure varies. In the absence of hydrogen bonding, other molecular interactions and polymer mechanics control hydrophobic ordering. Furthermore, these results provide new insights into how polymer chemistry specifically impacts water-polymer interactions and translates to surface hydrophobicity. Such factors may facilitate the design or processing of polymer surfaces to achieve targeted wetting behavior, and presented analyses can be useful in studying the interfacial physics of other systems.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2013

Mathematical analysis as required by a tachyonic observer

We rely on an analysis of initial states of the wave function associated with the simplest relativistic particle—the Weyl neutrino—to construct two series of representations of SL(2,R), or of the twofold cover of this group, by operators acting on scalar functions defined on the real line. The first one, which depends on a parameter p= 0, 1, …, contains the usual one-dimensional metaplectic, or oscillator, representation. The second one, a series of representations no longer unitary but, for certain values of the parameter, pseudo-unitary with respect to some non-degenerate indefinite pseudo-scalar product, is built in a comparable way, only exchanging the time coordinate with one of the spatial ones. The first series of representations was originally introduced in connection with automorphic pseudodifferential analysis; the second one is new, except for one value of the (continuous, in this case) parameter ρ, in which case it coincides with the recently introduced anaplectic representation. For each value of the parameter λ (=p or ρ), the basic operators Q and P from the usual Heisenberg pair give way to a new pair (Q, P{sub λ}) and to another analysis of functions on the real line, with as rich a collection of (most of the time totally new) symmetries as the usual one. The unusual set of coordinates in Minkowski's space under consideration can be regarded as corresponding to a “tachyonic observer,” a notion which does not require venturing into debatable questions of Physics. On the other hand, the paper indicates in a special example the way one may recover well-posedness (in a non-classical sense) for an initial-value problem with data on a timelike surface.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2016

Atomistic modeling of dropwise condensation

The basic aim of the atomistic modeling of condensation of water is to determine the size of the stable cluster and connect phenomena occurring at atomic scale to the macroscale. In this paper, a population balance model is described in terms of the rate equations to obtain the number density distribution of the resulting clusters. The residence time is taken to be large enough so that sufficient time is available for all the adatoms existing in vapor-phase to loose their latent heat and get condensed. The simulation assumes clusters of a given size to be formed from clusters of smaller sizes, but not by the disintegration of the larger clusters. The largest stable cluster size in the number density distribution is taken to be representative of the minimum drop radius formed in a dropwise condensation process. A numerical confirmation of this result against predictions based on a thermodynamic model has been obtained. Results show that the number density distribution is sensitive to the surface diffusion coefficient and the rate of vapor flux impinging on the substrate. The minimum drop radius increases with the diffusion coefficient and the impinging vapor flux; however, the dependence is weak. The minimum drop radius predicted from thermodynamic considerations matches the prediction of the cluster model, though the former does not take into account the effect of the surface properties on the nucleation phenomena. For a chemically passive surface, the diffusion coefficient and the residence time are dependent on the surface texture via the coefficient of friction. Thus, physical texturing provides a means of changing, within limits, the minimum drop radius. The study reveals that surface texturing at the scale of the minimum drop radius does not provide controllability of the macro-scale dropwise condensation at large timescales when a dynamic steady-state is reached.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗
DOE OSTI2015

Model catalysis by size-selected cluster deposition

This report summarizes the accomplishments during the last four years of the subject grant. Results are presented for experiments in which size-selected model catalysts were studied under surface science and aqueous electrochemical conditions. Strong effects of cluster size were found, and by correlating the size effects with size-dependent physical properties of the samples measured by surface science methods, it was possible to deduce mechanistic insights, such as the factors that control the rate-limiting step in the reactions. Results are presented for CO oxidation, CO binding energetics and geometries, and electronic effects under surface science conditions, and for the electrochemical oxygen reduction reaction, ethanol oxidation reaction, and for oxidation of carbon by water.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗