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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 145 records · Page 8
All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

TWF Waste Container Intra-Facility Transfer and Outgoing Shipment

This procedure provides instructions for the inspection and transfer of Transuranic (TRU) Waste containers within the Transuranic Waste Facility (TWF) (Waste Storage Buildings [WSBs], Characterization Waste Storage Building [CWSB]) and Characterization Trailers. This also includes the preparation to transfer to other LANL facilities. Performance of this procedure meets the requirements of SR 4.2.1.1, 4.2.1.2, 4.2.1.4, 4.2.1.5, 4.3.4.1, SAC 5.9.1, SAC 5.9.3 and AC 5.8.13 2nd bullet, as well as requirements set forth in the Los Alamos National Laboratory (LANL) Hazardous Waste Facility Permit (HWFP).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2020

TWF Waste Container Receipt, Inspection and Transfer to Storage

This procedure provides instructions for the receipt, inspection, and transfer to storage of Transuranic (TRU) Waste Containers and Pipe Overpack Containers (POC) within the Transuranic Waste Facility (TWF) (Waste Storage Buildings [WSBs] and Characterization and Waste Storage Building [CWSB]). Performance of this procedure meets the requirements of AC 5.8.9, AC 5.8.13 2nd Bullet, SAC 5.9.1, SAC 5.9.3, SR 4.2.1.1, 4.2.1.2, 4.2.1.5, 4.2.1.6, 4.2.2.1, 4.2.2.2, 4.2.2.3, 4.2.2.4, 4.2.3.1, 4.2.3.2, 4.2.3.3, 4.3.4.1, 4.4.1.1, 4.4.1.2 and 4.4.1.3.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

Multi-Sourced Collaboration for the Production and Refining of Rare Elements and Critical Metals (Final Technical Report)

The project objective was to develop a feasible and cost-effective method for recovering rare earth elements (REEs) and critical materials (CMs) from coal and coal byproducts, resulting in high-purity individually separated REEs and CMs. The targeted REEs included Y, Pr, Nd, Gd, Dy, and Sm, with a purity of over 99.5%, while the CMs included Co, Mn, Ga, Sr, Li, Ni, Zn, and Ge, with a purity of over 90%. The project aimed to design a prototype facility capable of producing 1-3 tonnes/day of high-purity REO mixes. The work was divided into four designated circuits: 1) REE extraction and concentration, 2) REE separation and purification, 3) RE metal production, and 4) CM production. To achieve these goals, the project involved 11 tasks, including technology reviews, research, process flow diagram development, mass balance estimation, and preliminary technical-economic analysis. The project team included researchers from the University of Kentucky, University of Alabama and Virginia Tech as well as process specialists from Argonne National Laboratory. MP Materials provided technical support regarding rare earth markets and processing while Alliance Coal performed resource assessment. The project included a market analysis for Nd/Pr, Tb, Dy, Gd, Y, Co, Mn, Li, Sr, Ga, Ni, Zn, and Ge. These analyses provided insights into the supply and demand trends as well as historic and future projections of market price relative to purity requirements for these elements. Two coal resources were selected for the project: the West Kentucky No. 13 (Baker) Seam and an undisclosed lignite resource in the Illinois coal basin. The estimated quantities of REEs in these resources were calculated based on production samples and drilling data. It was estimated that there is adequate supply for an operation producing one metric ton daily of higher purity mixed rare earth oxides (MREO) for approximately 20 years at a site located in western Kentucky. In Circuit 1, project data was obtained from a pilot heap leach and REE concentration facility. It was concluded that the existing circuit, which generated a MREO concentrate, two types of CM mixed products, and Li- and Sr-containing waters, would be suitable feed for circuits 2-4. Data from the first-of-its-kind coal coarse refuse heap leach pilot pad played a crucial role in estimating reliable elemental concentrations of the pregnant leaching solution (PLS). The average total REE concentration in the PLS was found to be 28.6 ppm. In Circuit 2, several concepts were explored including a novel process referred to as solvent-assisted chromatography (SAC). This concept involved a novel columnar reactor that incorporated multiple mixer/settlers, thereby enabling the operation of counter-flowing aqueous and organic phases. Unfortunately, due to project time constraints, a complete fundamental modeling analysis could not be completed to fully evaluate the technology. Molten salt electrowinning was considered as an alternative for circuit 3 following circuit 2 purification circuit utilizing the novel SAC process. A mass and energy balance of Nd reduction to metal in a fluoride containing molten salt electrolyte was conducted. Comparisons were made with the current state of Asian molten salt electrorefining, and potential improvements in siphoning rare earth metals (REM) from the reactor were presented. A cost estimate was performed for the production of 1 tonne per day, which yielded a total of $2.29 million for the nine electrowinning (EW) cells required. The selected option for circuits 2 and 3 was a plasma distillation process, which initially separates rare earth elements (REEs) from other elements. This is followed by selective electrowinning in various ionic liquids. The selection was made on the basis of thermodynamic modeling and experimental data previously published by a project partner. The combination offers an innovative approach to integrated refining and RE metal production. For Circuit 4, an extensive literature review was conducted for the processing of the CMs. The ultimate decision was to utilize a combined plasma and ionic liquid process as well to produce individual high-purity concentrates of Zn, Ni, Co, Mn, and Mg. A separate flowsheet for Li and Sr was recommended, which would yield carbonates of these elements. Due to the lack of suitable experimental data at this time, a process recommendation could not be provided but several methods have been proposed for consideration. Lastly, a techno-economic analysis (TEA) was conducted to assess the effectiveness of the proposed process for further investigation. The TEA results revealed a capital expense (CapEx) of $737 million and an annual operational expense (OpEx) of $220 million. Due to the selected elements, the hypothetical heap leach pad can produce 1 metric tonne per day of REO equivalent, but a conscious decision was made to only treat targeted REEs, resulting in the production of 0.4 metric tonne of REM. An estimated annual revenue of $90.87 million was projected based on standard market pricing information provided by the funding agency. During the TEA, ten different modules were evaluated for costing purposes. The precipitation circuit was identified as the largest single operational expense, followed by the Mg/Mn process due to the amount of treated metal. In terms of capital expenditures, the heap leach process incurred the highest cost, followed by the Mg/Mn process. The scalability of the plasma process is a crucial consideration since the reactors cannot be scaled beyond the largest demonstrated size due to their reliance on surface area of the slag and vapor phase. The purity estimate for the REEs are generally 98%±2% to produce a metal. The purity level being lower than the project objective was due to the lack of specific experimental data needed to tighten the tolerance of the estimates. Based on literature and previous experience, the CMs are estimated as follows; Ga (95%+, metal), Sr (95%+, carbonate), Li (95%+, carbonate), Ni (98%±2%, metal), Zn (95%+, metal sponge), Ge (95%+, metal), Co (98%±2%, metal), and Mn (98%±2%, metal).

01 COAL, LIGNITE, AND PEAT↗
DOE OSTI2022

Effect of single atom Platinum (Pt) doping and facet dependent on the electronic structure and light absorption of Lanthanum Titanium Oxide (La 2 Ti 2 O 7 ): A Density Functional Theory study

Charge generation and separation are two key processes for semiconductor photocatalysis. Here, we use Pt as a single atom catalyst to systematically examine the facet-dependent electronic band structure and light absorption of the layered perovskite-type wide-gap semiconductor, lanthanum titanium oxide (La 2 Ti 2 O 7 , LTO) by means of density functional theory simulations. In this study, it is found that single Pt atom doping of different LTO surfaces (here, (100), (101) and (001)) can not only create states in the bandgap that would promote the formation of recombination centers, but also shift the optical absorption edge to the visible region. Interestingly, the Pt doping forms a heterojunction, with the valence band maximum consisting of Pt states and the conduction band minimum consisting of LTO states, respectively. To study the facet dependent surface activity, acetic acid (CH 3 COOH) was used as a model molecule to investigate the adsorption and charge transfer on the (101), (100) and (001) Pt-LTO surface facets. The results show that the (101) facet could enable stronger adsorption of CH 3 COOH by promoting more electron transfer during the interfacial interaction. Our theoretical findings aim to promote the design and optimization of the single atom catalysts (SACs) for photocatalytic applications and other broad catalysis systems.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2023

Nickel‐Based Single‐Molecule Catalysts with Synergistic Geometric Transition and Magnetic Field‐Assisted Spin Selection Outperform RuO 2 for Oxygen Evolution

Overcoming slow kinetics and high overpotential in electrocatalytic oxygen evolution reaction (OER) requires innovative catalysts and approaches that transcend the scaling relationship between binding energies for intermediates and catalyst surfaces. Inorganic complexes provide unique, customizable geometries, which can help enhance their efficiencies. However, they are unstable and susceptible to chemical reaction under extreme pH conditions. Immobilizing complexes on substrates creates single‐molecule catalysts (SMCs) with functional similarities to single‐atom catalysts (SACs). Here, in this work, an efficient SMC, composed of dichloro(1,3‐bis(diphenylphosphino)propane) nickel [NiCl 2 dppp] anchored to a graphene acid (GA), is presented. This SMC surpasses ruthenium‐based OER benchmarks, exhibiting an ultra‐low onset and overpotential at 10 mAcm −2 when exposed to a static magnetic field. Comprehensive experimental and theoretical analyses imply that an interfacial charge transfer from the Ni center in NiCl 2 dppp to GA enhances the OER activity. Spectroscopic investigations reveal an in situ geometrical transformation of the complex and the formation of a paramagnetic Ni center, which under a magnetic field, enables spin‐selective electron transfer, resulting in enhanced OER performance. The results highlight the significance of in situ geometric transformations in SMCs and underline the potential of an external magnetic field to enhance OER performance at a single‐molecule level.

in situ geometrical changes↗
DOE OSTI2020

Atomically Dispersed Nickel(I) on an Alloy‐Encapsulated Nitrogen‐Doped Carbon Nanotube Array for High‐Performance Electrochemical CO 2 Reduction Reaction

Abstract Single‐atom catalysts (SACs) show great promise for electrochemical CO 2 reduction reaction (CRR), but the low density of active sites and the poor electrical conduction and mass transport of the single‐atom electrode greatly limit their performance. Herein, we prepared a nickel single‐atom electrode consisting of isolated, high‐density and low‐valent nickel(I) sites anchored on a self‐standing N‐doped carbon nanotube array with nickel–copper alloy encapsulation on a carbon‐fiber paper. The combination of single‐atom nickel(I) sites and self‐standing array structure gives rise to an excellent electrocatalytic CO 2 reduction performance. The introduction of copper tunes the d‐band electron configuration and enhances the adsorption of hydrogen, which impedes the hydrogen evolution reaction. The single‐nickel‐atom electrode exhibits a specific current density of −32.87 mA cm −2 and turnover frequency of 1962 h −1 at a mild overpotential of 620 mV for CO formation with 97 % Faradic efficiency.

Zhang, Tianyu↗
DOE OSTI2020

In Situ Dispersion of Palladium on TiO 2 During Reverse Water–Gas Shift Reaction: Formation of Atomically Dispersed Palladium

The application of single-atom catalysts (SACs) to high-temperature hydrogenation requires materials that thermodynamically favor metal atom isolation over cluster formation. Here, we show that Pd can be predominantly dispersed as isolated atoms onto TiO 2 during the reverse water-gas shift (rWGS) reaction at 400 °C. Achieving atomic dispersion requires an artificial increase of the absolute TiO 2 surface area by an order of magnitude and can be accomplished by physically mixing a precatalyst (Pd/TiO 2 ) with neat TiO 2 prior to the rWGS reaction. Furthermore, the in situ dispersion of Pd was reflected through a continuous increase of rWGS activity over 92 h and supported by kinetic analysis, infrared and X-ray absorption spectroscopies and scanning transmission electron microscopy. The thermodynamic stability of Pd under high-temperature rWGS conditions is associated with Pd-Ti coordination, which manifests upon O-vacancy formation and the artificial increase in TiO 2 surface area.

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

Surface Density Dependent Catalytic Activity of Single Palladium Atoms Supported on Ceria

The analogy between single-atom catalysts (SACs) and molecular catalysts predicts that the specific catalytic activity of these systems is constant. Here we provide evidence that this prediction is not necessarily true. As a case in point, we show that the specific activity over ceria-supported single Pd atoms linearly increases with metal atom density, originating from the cumulative enhancement of CeO 2 reducibility. The long-range electrostatic footprints (≈1.5 nm) around each Pd site overlap with each other as surface Pd density increases, resulting in an observed deviation from constant specific activity. These cooperative effects exhaust previously active O atoms above a certain Pd density, leading to their permanent removal and a consequent drop in reaction rate. The findings of our combined experimental and computational study show that the specific catalytic activity of reducible oxide-supported single-atom catalysts can be tuned by varying the surface density of single metal atoms.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Oxygen–coordinated low–nucleus cluster catalysts for enhanced electrocatalytic water oxidation

The oxygen evolution reaction (OER) activity of single-atom catalysts (SACs) is closely related to the coordination environment of the active site. Oxygen-coordinated atomic metal species bring about unique features beyond nitrogen-coordinated atomic metal species due to the fact that the M–O bond is weaker than the M–N bond. Herein, a series of metal–oxygen–carbon structured low-nucleus clusters (LNCs) are successfully anchored on the surface of multiwalled carbon nanotubes (M-MWCNTs, M = Ni, Co, or Fe) through a foolproof low-temperature gas transfer (300°C) method without any further treatment. The morphology and coordination configuration of the LNCs at the atomic level were confirmed by comprehensive characterizations. The synthetic Ni-MWCNTs electrocatalyst features excellent OER activity and stability under alkaline conditions, transcending the performances of Co-MWCNTs, Fe-MWCNTs and RuO 2 . Density functional theory calculations reveal that the moderate oxidation of low-nucleus Ni clusters changes the unoccupied orbital of Ni atoms, thereby lowering the energy barrier of the OER rate-limiting step and making the OER process more energy-efficient. This study demonstrates a novel versatile platform for large-scale manufacturing of oxygen-coordinated LNC catalysts.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Boosting Electrochemical Catalysis and Nonenzymatic Sensing Toward Glucose by Single‐Atom Pt Supported on Cu@CuO Core–Shell Nanowires

Abstract It is critical to develop high‐performance electrocatalyst for electrochemical nonenzymatic glucose sensing. In this work, a single‐atom Pt supported on Cu@CuO core–shell nanowires (Pt 1 /Cu@CuO NWs) for electrochemical nonenzymatic glucose sensor is designed. Pt 1 /Cu@CuO NWs exhibit excellent electrocatalytic oxidation toward glucose with 70 mV lower onset potential (0.131 V) and 2.4 times higher response current than Cu NWs. Sensors fabricated using Pt 1 /Cu@CuO NWs also show high sensitivity (852.163 µA mM −1 cm −2 ), low detection limit (3.6 µM), wide linear range (0.01–5.18 µM), excellent selectivity, and great long‐term stability. The outstanding sensing performance of Pt 1 /Cu@CuO NWs, investigated by experiments and density functional theory (DFT) calculations, is attributed to the synergistic effect between Pt single atoms and Cu@CuO core–shell nanowires that generates strong binding energy of glucose on the nanowires. The work provides a new pathway for exploring highly active SACs for electrochemical nonenzymatic glucose sensor.

Chemistry↗
DOE OSTI2021

Operando XAS/SAXS: Guiding Design of Single-Atom and Subnanocluster Catalysts

Single-atom and subnanocluster catalysts (SSCs) represent a highly promising class of low-cost materials with high catalytic activity and high atom-utilization efficiency. However, SSCs are susceptible to undergo restructuring during the reactions. Exploring the active sites of catalysts through in situ characterization techniques plays a critical role in studying reaction mechanism and guiding the design of optimum catalysts. In situ X-ray absorption spectroscopy/small-angle X-ray scattering (XAS/SAXS) is promising and widely used for monitoring electronic structure, atomic configuration, and size changes of SSCs during real-time working conditions. Unfortunately, there is no detailed summary of XAS/SAXS characterization results of SSCs. The recent advances in applying in situ XAS/SAXS to SSCs are thoroughly summarized in this review, including the atomic structure and oxidation state variations under open circuit and realistic reaction conditions. Furthermore, the reversible transformation of single-atom catalysts (SACs) to subnanoclusters/nanoparticles and the application of in situ XAS/SAXS in subnanoclusters are discussed. To conlcude, the outlooks in modulating the SSCs and developing operando XAS/SAXS for SSCs are highlighted.

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
DOE OSTI2022

Regulating Electronic Structure of Single-Atom Catalysts toward Efficient Bifunctional Oxygen Electrocatalysis

We report electronic structure of single-atom catalysts (SACs) is critical for bifunctional oxygen electrocatalysis by adjusting the binding energy in oxygen-containing intermediates. However, the regulation of electronic structure has always been a challenge to improve catalytic reactivity. Herein, by introducing a heterogenous metal, the electronic structure through a direct bonding interaction to the active center atom is effectively adjusted. Partial charge transfer between the two atoms optimizes the binding energy of intermediates and reducing the energy barrier of the catalytic reaction. Theoretical calculations confirm these effects and the uniform distribution of 3d orbitals, leading to the improvement of bifunctional oxygen electrocatalytic reactivity. Benefiting from these attributes, the as-constructed bifunctional catalyst enables outstanding electrocatalytic performances in both oxygen reduction and hydrogen oxidation in various energy storage systems. The generality and expandability of this strategy is demonstrated by further successful development of other dual-metal catalysts systems with various active metals.

36 MATERIALS SCIENCE↗
DOE OSTI2023

Factors Influencing Propensity for Stress Relaxation Cracking in Inconel® Alloy 740H® and Practical Guidance for Applications

Inconel® alloy 740H® (UNS N07740) was the first age-hardenable nickel-based alloy approved by the ASME Boiler & Pressure Vessel Code for use in pressure-boundary applications. In recent years, advanced energy systems such as supercritical CO2 power cycles have utilized alloy 740H in large demonstration projects driven by the requirement for higher fluid temperatures and pressures. Stress relaxation cracking (SRxC) following post-weld heat-treatment (PWHT), also known as strain age cracking (SAC), has been identified in a limited number of weldments during these industrial builds resulting in focused research to further clarify factors influencing this cracking tendency. This paper will summarize some of the findings from shop and field fabrication leading to successful welds and characteristics of observed SRxC. Laboratory experiments supported by microstructural characterization will be presented to highlight the importance of variables such as strain, material starting condition, and PWHT temperatures. Finally, the results will be summarized within the context of practical guidance for industry to successfully weld the material in boiler, heat exchanger, and piping applications.

14 SOLAR ENERGY↗
DOE OSTI2026

Optimization of the FRIB beam dump: a hybrid genetic algorithm and reinforcement learning approach

The operational envelope of high-power-density systems, such as particle accelerators and advanced nuclear energy systems, is critically constrained by the need to manage extreme thermal loads. To address this, we present a novel hybrid optimization framework combining a genetic algorithm (GA) with a soft actor-critic (SAC) deep reinforcement learning agent. This framework was applied to a practical high-heat-flux problem: redesigning the beam dump at the Facility for Rare Isotope Beams (FRIB) for a power upgrade from 20 kW to 50 kW. The resulting design, validated by three-dimensional conjugate heat transfer simulations, suppresses hazardous hot spots and yields a markedly more uniform temperature distribution. This provides a robust operating margin, increasing the average power-handling capability by 72% relative to the current design, demonstrating the framework’s potential to solve complex thermal management challenges in both accelerator technology and advanced nuclear systems.

Accelerator↗
DOE OSTI2023

Online transfer learning strategy for enhancing the scalability and deployment of deep reinforcement learning control in smart buildings

In recent years, advanced control strategies based on Deep Reinforcement Learning (DRL) proved to be effective in optimizing the management of integrated energy systems in buildings, reducing energy costs and improving indoor comfort conditions when compared to traditional reactive controllers. However, the scalability and implementation of DRL controllers are still limited since they require a considerable amount of time before converging to a near-optimal solution. This issue is currently addressed in literature through the offline pre-training of the DRL agent. However this solution results in two main critical issues: (1) the need to develop a building surrogate model to perform the training task, and (2) the need to perform a fine-tuning process over several training episodes to obtain a near-optimal control policy. In this context, this paper introduces an Online Transfer Learning (OTL) strategy that exploits two knowledge-sharing techniques, weight-initialization and imitation learning, to transfer a DRL control policy from a source office building to various target buildings in a simulation environment coupling EnergyPlus and Python. A DRL controller based on discrete Soft Actor–Critic (SAC) is trained on the source building to manage the operation of a cooling system consisting of a chiller and a thermal storage. Several target buildings are defined to benchmark the performance of the OTL strategy with that of a Rule-Based Controller (RBC) and two DRL-based control strategies, deployed in offline and online fashion. The strategy adopted for OTL emulates the real world implementation with a simulation process by implementing the transferred DRL agent for a single episode in the target buildings. Target buildings have the same geometrical features and are served by the same energy system as the source building, but differ in terms of weather conditions, electricity price schedules, occupancy patterns, and building envelope efficiency levels. The results show that the OTL strategy can reduce the cumulated sum of temperature violations on average by 50% and 80% respectively when compared to RBC and online DRL while enhancing the energy system operation with electricity cost savings ranging between 20% and 40%. Furthermore, the OTL agent performs slightly worse than the offline DRL controller but it does not require any modeling effort and can be implemented directly on target buildings emulating a real-world implementation.

32 ENERGY CONSERVATION, CONSUMPTION, AND UTILIZATI↗
DOE OSTI2022

Development of simplified model for injection rate prediction of diesel injectors during transient and steady operation

Determining the injection rate of the diesel injector during the transient short injection operations is a critical matter to enhance the combustion process by improving air/fuel mixture formation. In this regard, numerous injection models have been suggested in the literature to predict the injection rate accurately. However, such algorithms have not precisely predicted the rate of injection (ROI) in transient short injection events. In addition, most of those models require many input parameters to characterize hydraulic and mechanical subsystems in the injector, which can make them inconvenient to tune for different injector specifications, in other words not suitable for universal usage. Therefore, our study aims to develop a simple injection model that can predict injection rate precisely in the short and long injection durations considering relatively fewer input parameters. The model traces the pressure variation inside the sac based on the bulk modulus theory to predict nozzle exit velocity, thus the injection rate of the injector. In the algorithm, the bulk modulus of fuel (E) and discharge coefficients of the nozzle hole and needle seat (C d,H and C d,N ) have been considered to vary rather than set constant during the injection process since such flow parameters would have a critical impact on the flow development at the transient stage, thus affecting the injection rate of diesel injectors. Here with this modelling strategy, the accuracy of the new model on ROI prediction was confirmed with acceptable model error for both short and long injection durations by validating against experimental results. To understand the effect of the new model scheme on ROI prediction, ROI results with the new model have been discussed by comparing it with the ROI results predicted with constant flow parameters.

42 ENGINEERING↗
DOE OSTI2021

Vortex Flow and Cavitation in Liquid Injection: A Comparison between High-Fidelity CFD Simulations and Experimental Visualizations on Transparent Nozzle Replicas

Experimental instantaneous shadowgraph visualizations on transparent glass nozzle replicas of high-pressure fuel injectors have been used to validate a novel in-house high-fidelity LES-VOF multiphase solver, to study the evolution of vortex flow and fuel cavitation. Both experiments and simulations capture the formation of an unsteady vapor structure inside the nozzle volume, which is referred to as 'string-cavitation'; strings are found at the core of the recirculation zones. Furthermore, high-fidelity simulations provide a very detailed insight into the vortex generation in the injector nozzle; strings appear within the time scales that are relevant for fast injection events (on the order of 0.1 milliseconds) and, for the problem under consideration, their generation seems mostly related to the flow pattern in the sac. It is also shown that vortexes interact, merge till they disrupt and favor the temporary inception of shear cavitation.

3-phase LES-VOF solver↗